DE102008009139A1 - Laterally emitting step index fiber for e.g. contour illumination of ship, has scattering zone located between core and jacket, where particles are embedded in zone that includes refractive index differing from refractive index of jacket - Google Patents

Abstract

The index fiber has a light guiding core (1) and a transparent and/or translucent jacket (2) made of glass. The core and the jacket include refractive indexes, respectively. A discrete scattering zone (3) located between the core and the jacket is made of glass. Scattering particles are embedded in the scattering zone. The scattering zone includes a refractive index, which differs from the refractive index of the jacket. The particles contain oxides, metals, diamond-like carbon and/or glass ceramic particles. Glass in which scattering centers are embedded is an arsenic-lead silicate glass. An independent claim is also included for a method for producing a laterally emitting step index fiber.

Description

The The invention relates to side-emitting step index fibers, preforms and methods of making the same and side-emitting step index fibers containing fiber bundles and fabrics and their applications.

As step index fibers are understood to be light-conducting fibers, wherein the light conduction in the fiber core by total reflection of the guided light in the core takes place at the fiber core along the fiber axis enclosing jacket. The total reflection occurs when the cladding has a lower refractive index than the light-conducting fiber core. However, the condition of total reflection is possible only up to a critical angle of the light striking the cladding, which depends on the refractive indices of the core and cladding. The critical angle β _Min , ie the smallest angle at which the total reflection occurs, can be calculated by sin (β _Min ) = n ₂ / n ₁ , where β _{min is} measured from a plane perpendicular to the fiber axis, n _{1 is} the refractive index of the Fiber core and n _{2 represents} the refractive index of the cladding.

in the general, the best possible guidance of the Light in the fiber, d. H. it should as possible little light when coupled into the fiber and during transport get lost in the fiber. A side-emitting step index fiber is a step index fiber, intentionally emitting light from the fiber core and is decoupled from the fiber. In general, is a uniform Decoupling is desired, which is a side-emitting step index fiber ideally as a uniformly luminous band or line. This makes them for varied Applications especially in lighting technology interesting.

Seitenemittierend in the sense of the invention means that the fiber is capable of is to emit light sideways, regardless of whether she is in operation, d. H. whether actually a light source connected and the light is on.

The fibers are produced as generally known by means of fiber drawing processes, wherein at least the preform of the fiber core is heated to the softening temperature of the material of the preform or of the fiber core or beyond, and a fiber is drawn out. The principles of the fiber drawing process are, for example, in German patents DE 103 44 205 B4 and DE 103 44 207 B3 described in detail.

diverse Methods for generating the effect of the page emission are from the Known in the art. A well-known method is, for to provide a light extraction in the fiber core.

The Japanese patent application JP 9258028 A2 discloses side-emitting step index fibers in which light extraction is to be produced by a non-circular core. The decoupling takes place when light strikes the interface between the fiber core and the cladding at angles which are smaller than the critical angle of total reflection β _Min . The described non-circular core geometries, for example square, triangular or star shapes, generate geometric regions in the core in which light guided otherwise by total reflection can be coupled out. However, the generation of side emitting fibers by such core geometries has the problem that the outcoupling of the light in this case is very inefficient. The light is directed into the cladding at substantially shallow angles of incidence to the cladding, and the described core geometries extend along the fiber axis. Accordingly, there are hardly any surfaces in which β _min is exceeded. Furthermore, it is very expensive, in the JP 9258028 A2 disclosed glass fiber core geometries because it is very difficult to fabricate corresponding preforms as needed for the fiber tow. In addition, especially with glass fibers, the breaking strength of such fibers with non-round fiber core diameters is greatly reduced. For this reason, this document probably also discloses only fibers of polymers.

Another method to extract the light from the fiber core, in the US 4,466,697 described. Accordingly, light-reflecting and / or scattering particles are mixed in the fiber core. In this case, it is difficult to produce longer fibers with uniform side-emitting properties, since the light conduction in the core is attenuated by the added particles in the core by absorption, since there are no completely scattering particles, but only those that scatter only almost all of the incident light. Because the probability of uniformly distributed particles in the nucleus is very high that the light guided in the core hits such particles, the absorption probability is very high, even if the total number of particles is small. As a result, the coupling-out effect is also very difficult to scale, which makes reproducible results in the fiber tow extremely costly or nearly impossible, at least for fibers over 3 m in length, at least as long as glass fibers are to be produced.

Under Scalability in the sense of the present disclosure becomes the possibility the selective adjustment of the side emission effect understood the length of the fiber. This is necessary because Fiber lengths for different applications very much can vary greatly, but as even as possible Intensity of illumination over the entire fiber length should be achieved.

As an alternative to decoupling the light directly from the fiber core, side-emitting properties of fibers can also be caused by effects in the interface between the fiber core and the cladding or in the cladding itself. Thus, it is known from the prior art that crystallization reactions between core and cladding glasses are undesirable because the crystallites in the interface between core and cladding can serve as scattering centers, so that light decouples from the fiber and thus reduces its optical conductivity. This effect is generally undesirable in optical fibers, and glass fibers are as in the German patent DE 102 45 987 B3 described usually designed specifically designed so that a crystallization between the core and cladding does not take place. However, it would be conceivable that the crystallization between core and cladding is specifically used to produce side-emitting properties. Crystallization occurs during the fiber draw as the core and clad merge and the fiber cools again. However, it has been found in experiments that the crystallization process is difficult to adjust and control during the fiber draw, so that a reproducible and scalable production of side-emitting glass fibers whose side-emitting properties are based on the presence of crystallites in the interface between core and cladding, has not yet succeeded in an economic way.

For generating page-emitting properties due to scattering centers in the interface between core and cladding is described in the patent LV 11644 B For quartz glass fibers, it is proposed to apply a coating on the extended quartz glass fiber containing scattering particles. The outer protective sheath around the quartz glass fiber can then be applied. As is common with quartz glass fibers, the coatings of both the diffusing layer and the outer shell are made of plastics. This has the disadvantage that the extended fiber core must be subjected to further coating steps and is unprotected during this time. Dirt particles that settle between the core and the coating lead to possible breakage and / or to points with strong light extraction. Quart fibers are already extremely expensive as such because of the material, but the complex manufacturing process required in this document makes them even more expensive.

The US 2005/0074216 A1 discloses a side emitting fiber having a transparent plastic core having first a transparent first jacket and then a second jacket, both also made of plastic. In the second jacket, which is the outer jacket, scattering particles are embedded. This method is only possible with fibers with very large core diameters of 4 mm or more, because the light conducted in the fiber core must be coupled out by the inhomogeneities inevitably present at the very large interface between the core and the first cladding. In this case, the second shell with the incorporated scattering particles serves to homogenize the decoupled light over all solid angles. However, fibers with such a large core diameter are less flexible and can therefore be difficult to install. Made of glass such fibers can only be produced as rigid fiber rods and completely inflexible.

One serious disadvantage in all described solutions, which contain plastic is further that the described plastic shells all are flammable. Therefore, such fibers should generally be undesirable be. That being said, they can at least be in areas with increased fire safety regulations, for example within of aircraft cabins, are not allowed.

glass fibers are not flammable as such. Side emitting fibers are but also already known. The established method for Production of glass fibers with side-emitting properties sees before, the preform of the fiber core by grinding or sandblasting roughen. Through these machining processes are on the peripheral surface created the fiber core in the fiber core protruding structures, which should disengage the guided light. Here too shown that the process of generating the page emission inefficient and difficult to scale. About that In addition, editing of preforms, especially if these Made of glass, often expensive and expensive. The in the fiber core In addition, structures pose injuries of the fiber core, of which at bending loads load peaks and thereby cracks can occur, causing such fibers suffer from a reduced breaking strength. That's why it appears this technique needs improvement.

Against this background, it is an object of the invention to provide a side-emitting step index fiber that is economical to produce that efficiently decouples the light to the side, the Effect should be easily scalable, and which is also not flammable. Another object of the invention is to provide a method for producing such side-emitting fibers, as well as fiber bundles including such side-emitting fibers and their applications.

The Task and / or subtasks are solved by the independent claims. Preferred embodiments emerge from the dependent claims.

A side-emitting step index fiber according to the invention comprises a light-conducting core made of a glass with the refractive index n ₁ and a transparent and / or translucent cladding made of a glass with the refractive index n ₂ enclosing the core along the fiber axis, at least one scattering region being present between the core and the cladding, which is formed from a glass which has substantially the same refractive index n ₁ as the core and in which scattering particles are embedded. A side-emitting step index fiber of the invention may be flexible or rigid.

Of the Sheath encloses both as usual with fibers the core but also the or the scattering regions along the fiber axis Completely. The or the scattering areas are accordingly on the surface of the fiber core, protected by the coat.

Of the Side emission effect is achieved in the present invention Scattering of the light guided in the nucleus in a ratio to the core diameter thin area between core and cladding generated. This is located between core and mantle in immediate Contact between both a scattering area in which the scattering takes place. Responsible for the scattering are scattering particles, which are stored in the scattering area. Within the meaning of the invention scattering particles are all particles, of whatever shape, of which material and / or what size, which is the conducted light can scatter. Stray particles can be replaced by classic ones Scattering, especially Rayleigh and / or Mie scattering, as well as by Diffraction and / or reflection as well as multiple processes of these mechanisms unfold their scattering effect among each other. Your task is merely to distract light incident individually or in their totality.

The inventors have recognized that the effect of the side emission is best scalable if the scattering occurs mainly on the scattering particles themselves. For this purpose, the light guided in the core must first be able to reach it. Therefore, the refractive index of the material in which the scattering particles are incorporated is substantially equal to the refractive index n _{1 of} the core. The incorporation of the scattering particles in a matrix of glass is therefore necessary in the context of the invention in order to be able to apply it in the first place in an economical manner to the core. A refractive index of the matrix material deviating significantly from n ₁ would lead to the matrix material itself causing effects on the light conduction in the core. For example, if the refractive index were significantly less than n ₁ , the light guided in the core would be reflected from the material of the matrix rather than from the scattering particles, so that little to no scattering could occur on the scattering particles. Such a fiber would only couple out a little light to the side. If, on the other hand, the refractive index of the material of the matrix were significantly greater than n ₁ , the light conducted in the core would be very quickly released to the outside and the fiber would lose its entire light intensity over a very short length, so that only very short fiber lengths would be possible. Is the refractive index of the matrix material, however, is substantially equal to the refractive index n ₁ of the core, guided in the core light is disturbed at most insignificantly from the matrix material, so that the run in the core of light can be incident from the matrix material without hindrance to the scattering particles. Thus, the choice of the concentration of the scattering particles in the scattering range, an efficient scaling of the lateral emission is possible.

The greatest effect of the side emission can be achieved if there is at least one scatter zone between the core and the cladding, which completely surrounds the core along the fiber axis. This means that the scattering area extends over the entire circumferential surface of the fiber core. In turn, the jacket in turn encloses the entire structure of core and scattering area in turn. In this embodiment, the scattering particles are preferably distributed homogeneously in the scattering area. Such a scattering area is generated in the context of the invention during the fiber drawing by the fusion of several inlay bars, which consist of the matrix material into which the scattering particles are incorporated. The drawing method and the inlay bars are explained in more detail in connection with the description of the preform and the production method according to the invention. The use of the inlay bars and the resulting formation of a scattering area closed by the core by fusion of inlay bars makes it possible to dispense with the use of a tube to produce the scattering preform used for the fiber draw. This is advantageous because thus this preform does not have to be made by a tube of a glass in which scattering particles are incorporated. Such would be disadvantageous because a Rohrzuganlage would only needed for the production of these provided with scattering particles preforms, as in also for üb Liche glass pipes used Rohrzuganlagen scattering particles would usually be undesirable and their addition would contaminate the entire system. By dispensing with such a tubular preform, the side-emitting fiber according to the invention is thus more economical to produce.

A Another preferred embodiment provides that between core and shell at least one scattering area is located, the the core in a partial area along the fiber axis fully encloses. In other words, that means the scattering particles embedded only in parts of the matrix glass, these parts enclose the core in a ring shape. Is the distance between areas where scattering particles are present and such which have no scattering particles sufficiently large, can specifically a side-emitting fiber are produced, which shows the emission effect in some areas and in other areas Not. Such a fiber may be advantageous to a corresponding Design effect to achieve, or the light once with as possible little loss through the area without the side emission effect too to direct the place where the page emission is to take place. This allows the separation of light source, which in the Fiber is to be coupled, and the lighting location. fibers of this type can be made when inlay bars be used in the only partial areas along its axis Stray particles are stored. However, the fiber rope merges also the area of the inlay bars not doped with scattering particles with the fiber core, so that the amount of the sum of core diameter and Thickness of the scattering area without embedded scattering particles and with embedded scattering particles over the entire fiber length remains essentially the same.

In In a particularly preferred embodiment, the page-emitting Step index fiber at least a discrete range between Core and coat on, located on a portion of the core circumference extending along the fiber axis. This means that in this At least one scattering area along the fiber axis or partial areas extends along the fiber axis but does not completely surround the fiber. Such scattering areas can be generated when the inlay bars not at all or not completely at the fiber pull merge together. The generation of such discrete scattering areas can be determined by the number and / or diameter and thus adjust the volume of the used Inlaystäbe. Accordingly, at least one exists in this embodiment extending along the fiber axis region on the peripheral surface the core, which is not occupied with the material, in which otherwise the scattering particles are embedded. Of course But it is also possible that the or the along the Fiber axis extending discrete scattering areas as with respect to the preceding Embodiment described along the fiber axis regions in which no scattering particles are incorporated, so that the Fiber according to the invention in this case not over their entire length has the side emission effect, so that, for example, alternate areas with side emission to follow areas without page emissions.

The Lichtauskopplung the side-emitting step index fiber leaves characterized by the number of substantially along the fiber axis Scaling outstanding discrete scattering areas. There usually an efficient lateral extraction from the fiber is desired, has a particularly preferred inventive Side-emitting step index fiber between core and cladding several discrete scattering areas, each on a subarea of the core perimeter along the fiber axis. Preferred is the number of discrete scattering ranges from 5 to 100, particularly preferred from 10 to 50.

Usually be in the inventive page-emitting Step index fiber scattering particles used their melting temperature greater than the melting temperature of the glass, in which they are embedded. Because the scattering particles in this At least their scattering properties in the manufacturing process not change, their choices are facilitated and they can be purchased as raw material accordingly.

Prefers the scattering particles have a diameter between 10 nm and 5000 nm, more preferably between 100 nm and 1200 nm not round scattering particles is considered as diameter in the sense of the invention understood their maximum extent.

The scattering particles may be selected from a variety of materials. They preferably consist essentially of SiO ₂ and / or BaO and / or MgO and / or BN and / or AlN and / or SN and / or ZrO ₂ and / or Y ₂ O ₃ and / or Al ₂ O ₃ and / or TiO ₂ and / or Ru and / or Os and / or Rh and / or Ir and / or Ag and / or Au and / or Pd and / or Pt and / or diamond-like carbon and / or glass-ceramic particles. Mixtures of scattering particles made of different materials, compounds and / or conglomerates of these or fused together and / or sintered scattering particles are also conceivable and of the invention comprises as well as the metallic components of the aforementioned oxides and nitrides alone.

The Efficiency of decoupling from the scattering area and thus from the Fiber is next to the scattering property of the scattering particles as intrinsic parameter also on the concentration of scattering particles depending on the spread. It was found that concentrations the scattering particles in the scattering range between 10 ppm and 1000 ppm enable efficient decoupling, with the preferred Range is between 20 ppm and 100 ppm. The concentration information in ppm refers to the proportion of scattering particles in Ratio to the mass fractions of the constituents of the glass, in which the scattering particles are embedded. The parameters, with which preferably sets the side emission effect and thus Thus, the number of discrete scattering areas can be scaled along the fiber axis, the scattering properties of the scattering particles used and their concentration. By the suitable combination of these Parameters will be possible for the human Eye largely homogeneous appearing side-emitting fibers of different Length manufacture, so a variety of applications at all only possible.

Next the efficiency and homogeneity of the page emission but also the fibers of the invention as possible resist mechanical loads well. Are the fibers mechanical? Too sensitive, fiber breaks occur easily, which the Make fiber unusable. In particular, need the fibers of the invention repeatedly bent can be without breaking. A criterion to To judge the breaking strength of fibers is the so-called Loop test. A loop is formed from a fiber, which is drawn. The smaller the diameter of the sling, where the fiber breaks, the more break-proof it is.

Appropriate Breaking strengths can be produced by prestressed fibers. This means for the invention Fibers that the thermal expansion coefficient of the core glass greater than the thermal expansion coefficient of the jacket glass. In the manufacturing process of the fiber is Thus, the coat during cooling on the Core and / or the spreading area pulled, so that the coat a tension to the core and / or the spreading area. Such preloaded Fibers are usually much more resistant to breakage than unbiased ones Fibers. In addition to the described thermal preload are natural Other methods for generating the voltage possible. For example, the fiber could be during the manufacturing process or be chemically tempered afterwards. It would preferably by known processes for chemical toughening ions placed in the mantle, which is used to build up the tension responsible.

at a preferred side-emitting according to the invention Step index fiber is the diameter of the core of 10 microns to 150 microns, the at least one scattering range has a thickness of 100 nm to 2 μm and the cladding is between 500 nm and 2 μm thick.

Of course become the page-emitting Step index fibers in the rarest cases as single Fibers used but along with other side-emitting Step index fibers or together with other optical fibers, which have no side emission effect, in fiber bundles. The fiber bundle is itself usually from a protective outer coat surrounded, which consists in most cases of plastic. Fiber bundles have compared to a single fiber with the same diameter the advantage that they are much more flexible and can be installed in smaller bending radii. Out For this reason, almost only fiber bundles find a commercial Use in lighting applications. Because of this fact are also fiber bundles, which are the previously described side-emitting Step index fiber include, subject of this invention.

Also The fiber bundle does not necessarily have to be in the sense of the invention be flexible, it is also possible that the fiber bundle is designed as a rigid fiber rod, by later Forming, such as bending and / or pressing, in its final Shape is brought.

One includes fiber bundle according to the invention a variety of glass fibers and a variety of glass fibers along the fiber bundle axis completely enclosing outer Cloak, wherein the glass fibers have a variety of the previously described side-emitting step index fibers of the invention include and the outer jacket at least in Partial areas along the fiber bundle axis transparent and / or translucent. The transparency and / or translucency of the outer Mantels is therefore necessary for that of the individual fibers laterally emitted light also leave the fiber bundle can and therefore becomes visible to the viewer. Will be in place a transparent outer shell a translucent outer shell used, it is possible the side emitting light to homogenize the individual fibers.

The Fiber bundles according to the invention may typically from 100 to 10000 individual fibers.

Around highest demands regarding the fire safety of the to ensure fiber bundles according to the invention consists of the outer shell of the fiber bundle preferably made of flame-resistant plastics or of a fabric of Glass fibers. But it is also possible that the outer Coat by wrapping the plurality of glass fibers with one or a variety of glass fibers is produced. It is too possible, the individual fibers of the bundle together to spin, so that a kind of rope and / or yarn is produced, the no separate coat more needed.

By the invention makes possible side-emitting step index fibers with an efficient side emission where: the side emission effect also very good according to the requirements scalable, and thus the amount of decoupled light over the fiber length is easily adjustable. This will make it possible the side-emitting step index fibers of the invention also together with other light guides and / or other side emitting Step index fibers and / or textile fibers into a sheet connect to. A sheet is within the meaning of the invention an object, which in relation to its thickness one has large area. That way you can up the basis of the page-emitting invention Step index fibers a self-luminous, flat structure be generated, which light is homogeneous over the surface can emit distributed. Such a sheet is preferably designed so that a viewer it as a homogeneous luminous Surface perceives when the sheet is in operation is, d. H. when light enters the side-emitting step index fibers of the fabric is coupled.

In In a preferred embodiment, the page-emitting Step index fibers in such a sheet substantially are arranged parallel to each other. According to the radiation characteristic differently arranged side-emitting step index fibers within of the fabric are but of course equally possible.

Around to obtain a stable sheet are the side-emitting Step index fibers preferably fixed on a carrier element. In this way, a composite element of carrier element and side-emitting step index fibers. The carrier element is preferably also flat, but can be any shapes and have bulges.

alternative on the fixation of the side-emitting step index fibers on the Carrier element, these can also be in the carrier element be embedded and in this way a composite element of support element and form side-emitting step index fibers. This can be done by a Injection molding process, in which preferably transparent Plastic represents an encapsulation of the optical fibers. To can thermoplastic materials, eg. Polycarbonate, PVC, thermoplastic elastomers or silicones are used.

Prefers become the side-emitting step index fibers on the support element fixed by sewing and / or weaving. It is the same possible, the step index fibers also together and / or to sew with the support element. As sewing thread Both textile yarns and glass fibers can be used be used.

As a general rule The sheet can also by connecting the invention side-emitting step index fibers with a suitable carrier take place, for example by gluing, laminating if necessary together with a film and / or other suitable methods.

Especially preferred is the carrier element of the invention Sheet, on and / or in the side-emitting Step index fibers are fixed, transparent and / or translucent, so that the light through the step index fibers emits light through the carrier element can pass. To achieve Color effects can be colored the carrier element be.

to further stabilization of the fabric is in one another preferred embodiment of the invention also provided that the composite element of carrier element and side-emitting step index fibers having a stabilizing element connected is.

Especially Preferably, the stabilizing element is arranged so that the side emitting step index fibers between a surface the carrier element and a surface of the stabilizing element are located. The stabilizing element can thus also for protection contribute to the step index fibers. It is preferred on the back as a cover layer in the form of a film or a rigid plate arranged.

To increase the luminous efficacy, the side facing the side-emitting step index fibers is Preferably, the carrier element and / or the stabilization element is designed such that it can reflect the light emitted by the side-emitting step index fibers. This means that the side of the carrier element or the stabilizing element facing the step index fibers can be dyed white or formed in a mirror-like manner. This can be achieved particularly easily, for example, if aluminum foil is used as the stabilizing element. The carrier element in this case preferably consists of a transparent and / or translucent plastic such as Plexiglas. Of course, it is also possible to connect further stabilization elements with the composite element.

to Lichteinkopplung are the optical fibers by means of an optical fiber bundling summarized, wherein the light guides by means of end sleeves and / or adhesive tapes combined, usually glued and the end surfaces are ground and polished so that an optimal light coupling can take place. To increase the Luminance of the radiating surface can be the optical fibers Also be summarized on both sides, so that a two-sided Lichteinkopplung can be realized.

To the Operating the sheet according to the invention can emit light into the optical fibers and thus the side-emitting Step index fibers are coupled. As a light source to be preferably uses punctiform light sources, the optimal light output, the light by means of a lens attachment in such a way Focus that light within for the optical fibers specific acceptance angle is radiated. Because of your compact design and comparatively high light output in particular LEDs, particularly preferably white light LEDs or RGB LEDs proposed for light coupling. To light in the inventive To initiate the fabric it prefers measures for connection of at least one LED as a light source. Particularly preferred an inventive sheet Measures to connect at least one LED at opposite edges of the sheet before, leaving the light in the faces on both sides the step index fibers can couple.

Because the generation of the scattering range in the inventive side emitting fiber is a serious problem, is also the preform used in the manufacturing process, an essential part of the invention. The term "preform" is the One skilled in the art of fiber drawing. He includes that Structure from which the fiber is drawn. A conventional one Preform, which is used to produce glass fibers without side-emitting Properties used is usually a core bar made of glass, around the coaxial a cladding made of a glass is. The core rod can be made by pouring the glass into a mold be generated. Mostly a post-processing is for example by grinding or fire polishing necessary. The cladding tube can come from a pipe train. Method of making glass tubes are well known. When pulling the preform to the fiber merges the cladding tube with the core rod, leaving the Core rod of the fiber core and out of the cladding of the coat is formed. The fiber has a much smaller one Diameter than the preform on and off a single preform can In this way many kilometers of fiber are pulled.

A preform according to the invention for producing a side-emitting step index fiber includes a core rod of glass of refractive index n ₁ and a cladding of a glass of refractive index n ₂ , wherein the cladding surrounds the core rod along the core rod axis. Between core rod and cladding tube at least one inlay rod made of a glass is arranged parallel to the core rod axis, which essentially has the refractive index n ₁ and in which scattering particles are embedded. From the Inlaystäben the scattering areas are formed during fiber drawing.

Prefers has a preform according to the invention between core rod and cladding tube 5 to 100 inlay bars, which are parallel are arranged to the core rod axis. The inlay bars can arranged substantially at equal distances from each other be. However, the exact positioning of the inlay bars in the preform not necessarily essential for the later Appearance of the fiber bundle described, since due to inaccurate positioning resulting inhomogeneities by the plurality of side-emitting ones present in the fiber bundle Pick up fibers each other.

Prefers are used for the preform inlay bars whose Diameter of 0.2 mm to 2 mm.

Of the Diameter of the scattering particles in an inlay bar may be preferred from 10 nm to 2000 nm, more preferably between 100 nm and 1200 nm.

The scattering particles incorporated in the material of the inlay tube preferably include SiO ₂ and / or SiN and / or BaO and / or MgO and / or ZnO and / or Al ₂ O ₃ and / or AlN and / or TiO ₂ and / or ZrO ₂ and / or Y ₂ O ₃ and / or the metals of these oxides alone and / or BN and / or B ₂ O ₃ and / or Ru and / or Os and / or Rh and / or Ir and / or Ag and / or Au and / or Pd and / or Pt and / or diamond-like carbon and / or glass-ceramic particles.

Your Concentration in the at least one inlay bar is preferably between 10 ppm and 1000 ppm, more preferably between 20 ppm and 100 ppm.

To produce the side-emitting step index fiber according to the invention, at least one preform described above is first prepared as an intermediate product. For this purpose, a core rod made of a glass with the refractive index n _{1 is} provided, and around the core rod at least one inlay rod made of a glass with the refractive index n _{1 is arranged} parallel to the core rod axis. In the glass of Inlaystabes and / or the Inlaystäbe the scattering particles described above are stored. Then, around the core rod and inlay rods, a cladding tube made of a glass with the calculation index n _{2 is} arranged so that the core rod and the inlay rod and / or the inlay rods are located inside the cladding tube. However, it is also possible to arrange the or the inlay bars after the arrangement of core rod and inlay rod in the space between the core rod and cladding. The preform thus obtained is then fixed in a heating unit, heated in this and pulled out in a manner known to those skilled in the art to a glass fiber.

While of the fiber strand merge the core, and the respective inlay bar at the interface between core and inlay rod. The inlay bar is also transformed, d. H. if he has a round diameter in the preform showed, he forms after the fiber train a flat, slightly curved Area on the core perimeter area. Are in this area the scattering particles incorporated, so a along the fiber axis generated extensive spread. The scattering particles are on this way, so to speak, on certain areas of the core peripheral surface distributed. Merge several inlay bars together, It is possible that the scattering area is the core of the fiber in full, d. H. on its entire peripheral surface, encloses.

The Temperature at which the fiber pull occurs is drawing temperature called and lies above the softening temperature of the glass, from which the cladding tube consists. Usually are used for the core glasses, which is a have a lower softening temperature than the glass of the cladding tube, so that during heating in the heating unit also in the core rod, a temperature is reached, which is above the softening temperature the glass of the core rod lies. However, heating methods are also known, which allow the softening temperature of the core rod can be above the cladding tube. Prefers the drawing temperature is also above the softening temperature of the refractory glass used in the preform place. About setting the drawing temperature is the Viscosity of the glass during the fiber tension so influences that in conjunction with the pulling speed of a fiber the desired thickness can be obtained.

The Inlaystäbe, in which the scattering particles are embedded, must be essentially the same as previously described Have refractive index as the core rod. This is the easiest by achieving that same glass for core rod and inlay bars is used. Deviations of the refractive indices of Core rod and inlay rod and thus of fiber core and matrix glass of the Scattering caused by variations in the production of the glass can occur, are of the invention of course also includes.

Around the aforementioned discrete, extending along the fiber axis, but the core peripheral surface is not completely enclosing To get scattered areas, it sees the inventive Procedure before that when pulling out the preform at least one inlay bar merges with the core rod. If more than one inlay bar is used, they are arranged so that they are not completely together can merge. However, it is also possible that the inlay bars are arranged so that some with each other others merge, but not others. That way you can different width discrete scattering regions along the fiber axis be generated.

It However, it is also possible that generates a scattering area is to be, the full extent of the core along the fiber axis encloses. The scattered area then occupies the so to speak entire core perimeter area. This is achieved by the invention Method achieved when a plurality of Inlaystäben used and arranged in the preform so that they take off the preform merge both with the core rod and with each other. The thickness of the scattering area is by number and diameter the inlay bars adjustable.

Preferably, when the fiber is pulled out of the preform, a negative pressure is applied to it, ie a pressure is generated in the intermediate spaces of the preform which is lower than the pressure of the preform giving medium. As a result, the application of the cladding tube or of the jacket to the core rod or the fiber core and / or the inlay rods or the scattering area is assisted during the drawing process. This process aspect supports the application of the shell to the scattering area and / or core during the fiber draw and thus helps to avoid unwanted gaps in the drawn-out fibers.

In a preferred embodiment of the invention Method is used for the cladding tube a glass whose thermal expansion coefficient is smaller than the thermal expansion coefficient of the core glass used. The core glass is the glass from which the core rod and thus the Consist fiber core. As described above is achieved with that the sheath puts a tension on the fiber core and / or the one or the other Spreads exerts, so that the resulting fiber one has increased breaking strength.

The process according to the invention is particularly preferably used in a multi-fiber drawing machine. In a multi-fiber drawing machine, a corresponding number of fibers are drawn simultaneously from a plurality of preforms. In this way, fiber bundles can be produced efficiently. A Vielfaserfaserziehanlage is for example in the German patents DE 103 44 205 B4 and DE 103 44 207 B3 described in detail. In essence, several preforms are arranged side by side in a heating unit of a multi-fiber drawing machine and several side-emitting step fibers are pulled out simultaneously in a multi-fiber drawing machine, so that a fiber bundle is obtained which contains side-emitting step index fibers.

The fiber bundles obtained in this way can either be further processed or with other fiber bundles with or without side-emitting Properties to a larger fiber bundle be further processed. To protect the fiber bundle looks it is a particularly preferred embodiment of the invention Procedure before that around the fiber bundle an outer Sheath made of transparent and / or translucent plastic is extruded. Preferably, the plastic used is flameproof.

alternative The fiber bundle can be surrounded with glass fibers, which an outer non-combustible transparent and / or translucent coat to form the fiber bundle. This can by looping with other fibers or flipping with a fabric made of glass fibers.

Prefers becomes the page-emitting Step index fiber together with other light guides and / or others side-emitting step index fibers in a fiber bundle used, which as described above from an outer transparent and / or translucent coat is surrounded.

Around To produce rigid fiber bundles, the preforms are not as in the case of the flexible fiber bundles to fibers with diameters drawn from typically 50 microns to 150 microns, but to fiber rods of about 0.5 mm to 1 mm in diameter. Thereafter, about 200 to 10,000 of these fiber rods in a Jacket tube tightly packed, its diameter of about 10 mm 60 mm, and to a rigid fiber bundle with a diameter of about 0.5 mm to 20 mm pulled out. This fiber bundle has substantially the same side-emitting properties like a flexible fiber bundle. This results in above all application possibilities to typically about 2 m length for exactly straight lighting. By thermal deformation, such as bending and / or pressing, can from the straight fiber rods two-dimensional or three-dimensional Objects are produced. These can all be in the following be mentioned lighting solutions, but also lettering o. Ä .. Also, the production of flat fiber rods or generally non-round rigid fiber rods or plates is possible. Both fiber bundles of fiber rods as well as from flexible fibers are within the meaning of the invention of the Term fiber bundle includes.

One Fiber bundle according to the invention can be used for the accent lighting of interiors and / or facades to be used in architecture. Preference is given to the Fiber bundles along contours of interior components, for example, passages, support elements, outlines of buildings etc. and attached to suitable light sources connected. So it is possible to see the contours of a building or building parts through the fiber bundle with side-emitting Imitate fibers and a linear light source to realize.

Particularly preferably, the fiber bundle comprising the side-emitting fibers according to the invention is used for the accentuated illumination of interior spaces of vehicles, in particular of automobiles, aircraft, ships and / or trains. In this case, the fiber bundle can be attached anywhere or inserted in contours of these interiors. When light is coupled into the fiber bundle, it preferably appears as a luminous band or luminous line along these contours. As a result of that The fiber bundle can be designed so that it contains only flame-resistant materials, it can meet even very strict fire safety regulations. This makes it particularly suitable for use in vehicles of all kinds. In automobiles, a preferred mounting location of a fiber bundle according to the invention may be, for example, a door inner lining in which the contour of the recesses of the door opener, armrest, the transitions in the cladding material, etc. can be highlighted in this way. For airplanes and ships, the attachment along the window ribbons, hand luggage compartments, etc. offers. In aircraft and ships that the fiber bundle according to the invention can be used advantageously for marking escape routes.

As well preferred is the use of the invention Fiber bundles as part of furniture, in particular of seating, vehicle seats, living spaces and / or Kitchens. If the fiber bundle, for example, in the seams of seating such as armchairs, sofas, chairs etc., the contours of this furniture can be incorporated when lighting the fiber bundle accentuated as a luminous band become. When integrating into shelves, let cabinets in this way entire living landscapes with targeted lighting effects shape.

Especially in the automotive industry, the headlamps are increasingly being used by special lighting devices a recognition value Produce the manufacturer. Therefore, some automotive headlights Parking light rings, which surround the low beam and with activated Light appear as largely homogeneously luminous ring. Other For example, manufacturers use a band of LEDs in their headlights one. The fiber bundle according to the invention is preferably used in headlamps, especially of vehicle headlights of all kinds, especially preferred in headlamps of automobiles. The fiber bundle according to the invention allows it, any preferred homogeneous luminous structures in headlights to create. For various reasons LEDs also find increasingly applications in automotive headlights. Across from arranged in bands LEDs has this use according to the invention the advantage that few LEDs are sufficient to produce the lighting. In addition, compared to a band of LEDs no single points of light visible, which also for design reasons can be preferred. Also, one or more LEDs in the face of the invention Fiber bundles are coupled. In the sense of the invention Use is the function as position light within headlights which, in turn, for example, the applications as a parking light and include as daytime running lights.

A further preferred use of the invention Fiber bundle is the contour lighting of vehicles, in particular of automobiles, aircraft, ships and / or trains. If necessary, this contour lighting can be applied to the corresponding Vehicles replace or supplement the prescribed position lights and thus contribute to traffic safety.

Prefers is also the use of the invention Fiber bundles for the illumination of runways for Aircraft, such as airplanes, helicopters, airships etc .. So far, runways are covered by a variety of in one Row of arranged light bulbs lit. These have one limited lifetime, which is why in such a series again and again the failed light bulbs during operation of the airport must be replaced. Will the invention Fiber bundles along the runways and / or in their Centered, becomes a line-shaped luminous structure generates the location of the runway in the dark and / or bad Visibility conditions marked. The illumination source can the light into the fiber bundles at a few central points dock, which is not even in the immediate vicinity the runway must be located. The invention Fiber bundle is largely maintenance-free, so that itself the maintenance of this runway lighting on the few light sources used limited. In this way, for example the runways are marked by airports, but also of aircraft carriers, helipads and other aircraft.

Another preferred application of the sheet according to the invention is the backlighting of displays. Displays can be display devices of all types, but preferably flat-panel displays, for example computer monitors, flat-screen televisions and the displays of mobile telephones and PDAs (personal digital assistants). So far, large-format displays that require a backlight, illuminated by fluorescent tubes, which are located at the edge of the display or behind the display surface of the display. A possible homogeneous illumination of the display surface is desired, which is why between the fluorescent tubes and the display surface usually a diffuser plate is located, which homogenizes the light emitted from the fluorescent light. In diffuser plates, the light can also be coupled in laterally, for example when the fluorescent tubes are arranged at the edge of the display. The diffuser plate then acts as a light guide. For smaller displays, such as displays of mobile phones and / or PDAs, light from LEDs is usually coupled laterally into the diffuser plate. For larger displays, the LED lighting is still not a significant application, although it would be cheaper than the lighting with fluorescent tubes, because so far could not be realized sufficiently homogeneously illuminated light area. Remedy the page-emitting fiber bundles according to the invention can provide. If they are laid in suitable structures behind the display surface, behind or behind a diffuser plate as required, LEDs can couple light into the end faces of the fiber bundles, so that the fiber bundle or side emission features provide for the backlighting of the display. If the arrangement of the fiber bundle is matched with the intensity profile of the laterally emitted light, a large-area homogeneous background illumination for displays can be achieved in a cost-efficient manner.

All The above applications are also possible with a such fabrics. In particular, such a sheet can also designed as part of the seat of seating furniture but also of clothing and all for textiles known applications.

The The invention will be further explained with reference to the accompanying drawings. They show:

1a FIG. 5 is a longitudinal cross-sectional view along the fiber axis of a non-side-emitting step index fiber of the prior art. FIG.

1b FIG. 4 shows the cross-section of a non-side-emitting step index fiber of the prior art. FIG.

2a FIG. 2: the longitudinal section along the fiber axis of a side-emitting step index fiber according to the invention with the core completely enclosing the scattering region. FIG.

2 B FIG. 2: the cross section of a side-emitting step index fiber according to the invention with the core completely enclosing the scattering range. FIG.

3a FIG. 2: the longitudinal section along the fiber axis of a side-emitting step index fiber according to the invention with scatter regions which completely surround the core in partial regions along the fiber axis.

3b FIG. 2: the cross-section of a side-emitting step index fiber according to the invention with scattering regions which completely surround the core in partial regions along the fiber axis.

4a FIG. 4: the longitudinal section along the fiber axis of a side-emitting step index fiber according to the invention with discrete scattering regions which extend on a partial region of the core circumference along the fiber axis. FIG.

4b FIG. 3 shows the cross-section of a side-emitting step index fiber of the invention having discrete scattering regions extending on a portion of the core perimeter along the fiber axis. FIG.

5a FIG. 2: the longitudinal section along the fiber axis of a side-emitting step index fiber according to the invention with discrete scattering regions, which extend in each case over a partial region of the core periphery over partial regions along the fiber axis.

5b FIG. 2: shows the cross-section of a side-emitting step index fiber according to the invention with discrete scattering regions, each of which extends on a partial region of the core periphery over partial regions along the fiber axis.

6a a preform according to the invention for producing a side-emitting step index fiber.

6b A fiber bundle including side-emitting step index fibers.

7 : the scheme of a multi-fiber drawing machine.

8th a section transverse to the fiber axis through a sheet according to the invention, wherein the side-emitting step index fibers are fixed between a support member and a stabilizing element.

9 FIG. 4: a section transverse to the fiber axis through an alternative sheet according to the invention, in which the side-emitting step index fibers are embedded in a carrier element.

10 a section transverse to the fiber axis through a sheet according to the invention, wherein the side-emitting step index fibers are fixed as a fiber bundle on a support member and the structure is encapsulated in a housing.

11 : a sheet with measures for connecting light sources

12 : the schematic section through a display including a surface element according to the invention for backlighting of the display.

13 : a sheet corresponding 11 but with measures to connect light sources to both faces of the side-emitting step index fibers.

14 : an aircraft interior with applications of fiber bundles with side emitting properties.

15a : An automotive headlamp with fiber bundles with side emitting properties.

15b Another automobile headlamp with fiber bundles with side-emitting properties.

16 : a building with an accentuated luminous top.

17 : the runway of an airport with a luminous runway marker.

18 : Measurement curves of the brightness distribution of inventive side-emitting step index fibers in comparison to the prior art.

19 : Measuring curves of the spectral transmission of inventive side-emitting step index fibers.

All Figures are schematic, the diameters of their elements are not To scale and also the proportions All elements can interact with each other in the real objects differ from the drawings.

1a shows the longitudinal section along the fiber axis (A) of a step index fiber of the prior art. This step index fiber consists of a core ( 1 ) with the refractive index n ₁ . This is completely from the coat ( 2 ), which has the refractive index n ₂ . Incident light ( 4 ) is in the core ( 1 ), because due to the smaller refractive index n ₂ total reflection on the cladding ( 2 ) occurs. However, the condition of total reflection is possible only up to a critical angle of the light incident on the cladding, which depends on the values of the refractive indices of the core and cladding. The critical angle β _min can be calculated by sin (β _min ) = n ₂ / n ₁ , where β _{min is} measured from a plane perpendicular to the fiber axis.

The refractive indices of the fiber core and of the surrounding cladding are also relevant for the acceptance angle α _Max , which, measured from the fiber axis (A), describes the maximum angle of the light striking the end face of the fiber which can couple into the fiber. As a measure of the ability of the fiber to introduce obliquely incident light, the numerical N _{A operation of} the fiber is in use. It is calculated as N _A = n sin (α _Max ) = (n ₁ ² -n ₂ ² ) ^1/2 , where n represents the refractive index of the medium that passes through the light before coupling into the fiber.

1b shows the cross section of the fiber 1a ie a section transverse to the fiber axis (A). In the 1a and 1b The fibers shown have no side-emitting properties because they do not contain a scattering range.

2a shows a side-emitting step index fiber according to the invention in its longitudinal section along the fiber axis (A). This fiber has a scattering range ( 3 ) located between core ( 1 ) and coat ( 2 ) of the fiber is located and the core ( 1 ) completely encloses. Light coupled into the fiber ( 4 ) becomes in the spreading area ( 3 ) to the outside, ie radially decoupled from the fiber, even if the angle β _{Min is} exceeded. Without the existence of the spread ( 3 ) otherwise the condition of the total reflection would be fulfilled and the fiber would be the light essentially in the core ( 1 ) conduct. Responsible for the extraction of light ( 4 ) is the scattering of light ( 4 ) to the in the spreading area ( 3 ) stored scattering particles. Because the material of the spread ( 3 ), in whose matrix the scattering particles are embedded, has substantially the same refractive index n ₁ as the material of the core ( 1 ), the light ( 4 ) pass from the matrix material largely unhindered to the scattering particles. By single or multiple interaction with the scattering particles, it can be deflected by the scattering particles from its original angle of incidence so that the angle of incidence on the shell ( 2 ) is reduced so that it is smaller than β _min and can decouple the light from the fiber. Is the angle of incidence on the mantle ( 2 ) greater than β _min , there is a back reflection into the scattering range ( 3 ) or depending on the impact and / or interaction with the scattering particles in the nucleus ( 1 ).

Meets the light ( 4 ) on its way through the spreading area ( 3 ) randomly on no scattering particles, it hits the mantle ( 2 ) and behaves as if there were no scatter area. This means in this case that if the angle of passage through the scattering area ( 3 ) and thus the angle of impact on the jacket ( 2 ) is greater than β _min , the light from the cladding ( 2 ) back to the scatter area ( 3 ) is reflected back. The back-reflected light can in turn impinge on scattering particles as described above, which can result in beam paths which ultimately lead to a coupling out of the light from the fiber or to its conduction in the core (FIG. 1 ) being able to lead.

That the spreading area ( 3 ) completely encloses the core is based on 2 B clearly visible, which the cross section of the fiber after 2a shows.

In 3a is are scattered area ( 3 ) of the fiber shown are configured to alternately have regions with embedded scattering particles extending along the fiber axis (A) and the core (FIG. 1 ) according to the cross section 3b completely enclose and alternate with areas along the fiber axis (A), which indeed have the matrix material of the scattering area, but in which no scattering particles are embedded. Does that happen in the core ( 1 ) guided light ( 4 ) on scattered areas ( 3 ) with embedded scattering particles, the light ( 4 ) are radially decoupled according to the mechanisms described above with a certain probability. Meets in the core ( 1 ) guided light ( 5 ) but on areas of the scattering area, which have no scattering particles, it passes through these areas largely unhindered because they as described the same refractive index n ₁ as the core ( 1 ) and can by total reflection on the mantle ( 2 ) in the fiber. By selective adjustment of the interval between the scattering areas ( 3 ) with stored scattering particles and the areas without stored scattering particles, the amount of decoupled light can be adjusted. As already described, however, other parameters are responsible for the efficiency of decoupling.

4a shows the longitudinal section of a step index fiber according to the invention along the fiber axis (A), the discrete scattering regions ( 3 ), which extend along the fiber axis (A), which, however, according to the cross-section 4b can only extend to partial areas of the core circumference. In other words, in this case, only partial areas of the core circumferential area with scatter areas ( 3 ) covered. Therefore, in this case we are talking about discrete scattering areas. As previously described, these discrete scattering regions are created by fusing inlay rods with a core rod. In the 4b The form shown is purely schematic. The discrete scatter area ( 3 ) can be shaped anyway. In essence, the merging process determines the actual shape of the discrete scattering area ( 3 ). As based on 2a described, light ( 4 ) through the discrete scattering regions ( 3 ) are radially decoupled from the fiber.

Analogous to the embodiment according to 3a it is also in the presence of discrete scattering regions ( 3 ) corresponding 4a possible that the discrete scattering regions ( 3 ) are provided with scattering particles only on parts of their extent along the fiber axis (A). A longitudinal section along the fiber axis (A) of such a fiber is shown in FIG 5a shown, a cross section in 5b ,

6a shows a preform ( 10 ), which is suitable for producing a fiber bundle according to the invention with the core completely enclosing scattering areas or the core only on partial areas of the core circumference enclosing discrete scattering areas. It is thus necessary as a precursor of the fiber according to the invention. The preform ( 10 ) includes a core rod ( 11 ) around which the inlay bars ( 13 ) are arranged. The core rod ( 11 ) and the inlay bars ( 13 ) are of a cladding tube ( 12 ) surround. In most cases, core rod ( 11 ) and cladding tube ( 12 ) are aligned coaxially to each other, ie that the axis of Core rod ( 11 ) and cladding tube ( 12 ) lie substantially on top of each other, and between core rod ( 11 ) and cladding tube ( 12 ) the inlay bars ( 13 ) are located. The axes of the inlay bars ( 13 ) are usually parallel to the axis of core rod ( 11 ) and cladding tube ( 12 ).

In 6b is a fiber bundle ( 23 ) which comprises a multiplicity of side-emitting step index fibers ( 22 ) contains. In the present form, it is of an outer shell ( 24 ), which protects the bundle from mechanical stresses and which may consist of plastics and / or glass fibers as described.

The core rod consists of a glass with the refractive index n ₁ and the cladding made of a glass with the refractive index n ₂ . The inlay rods also consist of a glass with the refractive index n ₁ , in which the scattering particles are embedded. As described, it is preferred if the glass of the inlay bars ( 13 ) largely identical to that of the core rod ( 11 ), because the match of the refractive indices can best be ensured and there is also the least danger of undesirable contact reactions which can occur during fiber drawing and which can decisively reduce the fiber quality. To obtain a live fiber, the glass of the cladding tube ( 12 ) is preferably chosen such that its thermal expansion is smaller than that of the glass of the core rod ( 11 ).

When removing the preform ( 10 ) is removed from the core rod ( 11 ) the fiber core ( 1 ) and from the cladding tube ( 12 ) the coat ( 2 ). The inlay bars ( 13 ) with the stored scattering particles merge during fiber drawing with the core rod ( 11 ) and the cladding tube ( 12 ) and become the scattering areas ( 3 ). It is also possible that the inlay bars ( 13 ) merge with each other. Is there a correspondingly strong fusion and / or are there a sufficient number of inlay bars ( 13 ) in the preform ( 10 ), the inlay bars ( 13 ) during fiber pulling a range ( 3 ) forming the fiber core ( 1 ) according to the 2a to 3b completely encloses. Is the merger of the inlay bars ( 13 ) incomplete with each other, the discrete scattering areas ( 3 ) according to the 4a to 5b ,

7 shows the simultaneous fiber drawing of fibers ( 22 ) from several preforms ( 10 ) in a multi-fiber drawing machine. The preforms ( 10 ) are placed in a heating unit ( 20 ) brought in. At least the lower part of the preforms ( 10 ) drawing temperature is brought. Usually the heating unit ( 20 ) several heating bushes, each preform ( 10 ) is assigned a Heizbuchse. In the Heizbuchse are usually the means for heating the preform ( 10 ) contain. Multiple fibers ( 22 ) are pulled simultaneously according to the drawing, via a pulley ( 21 ) and wound on a take-up spool. On the take-up reel is a fiber bundle ( 23 ), which in this case is not surrounded by an outer jacket. The number of fibers in the fiber bundle corresponds to the number of simultaneously drawn fibers ( 22 ).

8th shows the basic structure of a sheet according to the invention as a section transverse to the fiber bundle axis (A). The individual side-emitting step index fibers ( 22 ) are here as a monolayer on a transparent support element ( 71 ) and thus fixed with this. This is due to the side-emitting step index fibers ( 22 ) emitted light ( 4 ) passes through the carrier element ( 71 ) and is preferably radiated from there in all possible spatial directions. The surface of the carrier element facing away from the step index fibers (US Pat. 71 ) thus acts as preferably homogeneous luminous radiating surface. At the back is a stabilizing element ( 72 ) are joined to the side-emitting step index fibers so that they are bonded to the support element ( 71 ) and the stabilizing element ( 72 ) form a sandwich structure. As a stabilizing element ( 72 ), for example, an aluminum foil can be used, the fixation can be done in a simple manner by gluing.

In 9 a variant is shown in which the predominantly parallel aligned side-emitting step index fibers ( 22 ) are encapsulated by a transparent plastic, which in this way the carrier element ( 71 ). This can be done in sections as an injection molding process or quasi endless as an extrusion process. The light emitted by the step index fibers ( 4 ) can preferably emit from both surfaces of the fabric. But it is also possible that a surface of the sheet is provided with a reflective layer, so that only the light emission can take place in one direction, but the intensity is increased.

In 10 the side-emitting step index fibers lie at least as part of spaced-apart fiber bundles ( 23 in which a multiplicity of side-emitting step index fibers ( 22 ) is included. The fiber bundles ( 23 ) on a carrier element ( 71 ) fixed with a reflective cover layer. The whole arrangement encapsulated ( 75 ). That of the fiber bundles ( 23 ) emitted light ( 4 ) occurs through the encapsulation ( 75 ). This can consist of a transparent plastic. However, other materials are also possible, so that a hermetic encapsulation of the sheet is made possible. Of course, it is also possible that in this encapsulation solution instead of the fiber bundles ( 23 ) also page-emitting step index fibers ( 22 ) on the carrier element ( 71 ) are fixed.

11 shows a sheet in which the page-emitting step index fibers ( 22 ) and / or fiber bundles ( 23 ) comprising the side-emitting step index fibers are arranged predominantly in parallel. The step index fibers ( 22 ) and / or the fiber bundles ( 23 ) are fixed to each other and / or with not shown support elements ( 71 ) and / or stabilizing elements ( 72 ). A light source ( 81 ) can be in the face of the step index fibers of the invention ( 22 ) and / or the fiber bundles ( 23 ) are coupled. For this purpose, the step index fibers ( 22 ) and / or the fiber bundles ( 23 ) by means of optical fiber bundling ( 83 ), so that the planar arrangement to a coupling surface ( 82 ) is transformed. In the coupling surface ( 82 ) are the faces of the step index fibers ( 22 ) Preferably summarized as possible. Will light from the light source ( 81 ) via the coupling surface ( 82 ) into the step index fibers ( 22 ) and / or the fiber bundles ( 23 ) and thus coupled into the fabric can, by the parallel stepped index fibers ( 22 ) and / or fiber bundles ( 23 ) are laterally coupled out and emitted from the surface ( 4 ).

Corresponding 13 the sheet can also have two coupling surfaces ( 81 . 82 ), so that in the fiber bundle ( 23 ) and / or the side-emitting step index fibers ( 22 ) light can be coupled from both end faces. Depending on the type of arrangement of the fiber bundles ( 23 ) and / or the side-emitting step index fibers ( 22 ) but also a higher number of coupling surfaces ( 81 . 82 ) possible.

12 1 shows the schematic section through a display including a surface element according to the invention for backlighting the display. In this case, a display unit (FIG. 91 ) by means of a plurality of spaced apart, mutually parallel optical fiber bundles ( 23 ) each having a plurality of side-emitting step index fibers ( 22 ) backlit. The fiber bundle ( 23 ) is on a support element ( 72 ), preferably on the fiber bundle ( 23 ) facing side is mirrored. The display unit ( 91 ) may be, for example, a TFT unit with the two polarizing plates and the liquid crystals in between. That of the fiber bundle ( 23 ) emitted light ( 4 ) passes through the TFT unit. In this application example, LEDs are particularly preferred as the light source ( 81 ) used.

In 14 the interior of an aircraft is shown, for example the cabin of a passenger plane. Fiber bundles incorporating the side emitting fibers of the invention can find a variety of applications in aircraft cabins. When the outer shells of the fiber bundles are formed from materials that are flame resistant, the fiber bundles that otherwise contain glass meet the approval requirements of the passenger airline certification authorities and the applicable manufacturer requirements. In 14 The side-emitting fiber bundles are sometimes shown as wide bands. This representation does not have to be scalable. Usually, the fiber bundles are used as a narrow fiber strand, which appears as a luminous line.

Such a light strip can be used as contour lighting ( 30 ) be installed along windows of the aircraft cabin, drawers of hand luggage storage or interior partitions. In general, any form of contour lighting within the aircraft cabin is possible. In the floor of the aircraft cabin is the side-emitting fiber bundle for marking the paths ( 31 ) mounted inside the aircraft. This way mark is particularly advantageous ( 31 ) to mark the routes to the emergency exits. It is also possible to use the side-emitting fiber bundles as contour lighting for seats ( 33 ) to use. In addition to the decorative effect, this application has the advantage that ambient light can be reduced to adjust nighttime conditions in the cabin, which are used by passengers to assist in sleep, but passengers can still find their seats. It has been recognized that, especially on long-haul flights, the insertion of sleep phases makes the journey more stress-free for the passengers. Therefore, more and more emphasis is placed on a suitable night equipment of aircraft interior cabins.

If the side-emitting optical fibers are used in the form of a sheet, for example by being woven with textile fibers, they can be integrated into the fabric of the seat covers. Then it is not only possible with the fibers to realize contour lighting, but also areas such as parts of the surface of the seats ( 32 ) bright.

15a shows an automobile headlight ( 40 ), take in the side-emitting fiber bundle lighting tasks. In this example, they enclose as a ring ( 41 ) Dimmed headlights ( 42 ) and or High beam ( 42 ). The side-emitting fiber bundles can thus be inside the headlight ( 40 ) are used as parking lights or daytime running lights.

In 15b is also an automobile headlamp ( 40 ) in which the side-emitting fiber bundle ( 45 ) as a strand below the main headlights ( 42 ) is arranged. Also in this example, it can perform the functions as a parking and / or daytime running lights in addition to decorative functions.

The application of the fiber bundle according to the invention ( 41 . 45 ) in automobile headlamps ( 40 ) is advantageous because the fiber bundle ( 41 . 45 ) consists at least predominantly of glass and thus is resistant to heat and weathering, which can be enhanced by the action of aggressive substances. The glass fiber bundle according to the invention is less susceptible to weathering and heat stress than side-emitting fiber bundles made of plastics. In addition, much higher light outputs can be coupled into fiber bundles of glass, as it is possible in fiber bundles made of plastic.

In particular, LEDs are particularly well suited for coupling into side-emitting fiber bundles, since their small compared to incandescent or gas discharge lamps radiating surface allows efficient coupling without a grußvolumige optics. This way, costs, weight and space can be saved in an automobile headlight. Compared to the attachment of band-shaped LEDs has the use of a side-emitting fiber bundle ( 41 . 45 ) in automobile headlamps ( 40 ) has the advantage that the light is emitted homogeneously, so that the aesthetically unsightly impression of individual luminous dots does not arise, other road users are not irritated by a large number of luminous spots, the luminous effect is largely independent of angle and the number of LEDs is reduced and thus energy in use of the headlamp can be saved, which in turn can reduce the fuel consumption of the vehicle.

16 shows the contour lighting ( 51 ) of parts of a building ( 50 ). In the present example, the building is a skyscraper, with the outlines of the dome appearing bright to the viewer through the side-emitting fiber bundles.

Based 17 is the application of the fiber bundles according to the invention with side-emitting properties as marking of runways of aircraft ( 60 ). Both the side mark ( 61 ) as well as a median strip ( 62 ) can be realized advantageously as described above by means of the side-emitting step index fibers according to the invention.

In 18 are the measured brightnesses of the side emission of side-emitting step index fibers according to the invention ( 90 . 91 . 92 ) in against the distance from the end face of the fiber applied. The curves ( 93 ) and ( 94 ) represent side-emitting step index fibers of the prior art as a comparison. The measurement of the brightness as a function of the distance gives the brightness distribution profile of the side-emitting fiber. The greatest possible brightness over the largest possible distance is desirable for most applications. The brightness values in the 18 are given in arbitrary units. Curve ( 91 ) shows the brightness distribution profile of a side-emitting step index fiber according to the invention, which were drawn out of a preform with 45 inlay bars, curve ( 92 ) one of a preform with 93 inlay bars and curve ( 90 ) one from a preform with 15 inlay bars. The scattering particles in all cases consisted of Pt. As can be seen, the brightnesses and thus the coupling-out efficiency of the side-emitting step index fibers according to the invention ( 90 . 91 . 92 ) are significantly larger than those known from the prior art ( 93 . 94 ).

Curve ( 94 ) represents a step index fiber in which a groove was milled into the preform of the core bar parallel to the core bar axis. The drawn-out fiber accordingly has a non-circular core with a notch along the fiber axis. As can be seen from the very low brightness values, the coupling-out efficiency of such a fiber is only very small, which is why it shows only a very weak side emission effect. It glows, so to speak, only very dark, which is why such a fiber is useless for most applications.

In the case of fiber, which by curve ( 93 ), the core of the fiber was doped with scattering particles. As you can see, such a fiber decouples reasonably well the guided light, however, within a short distance no side emission can be detected. As a result, even such a fiber is only disadvantageous for applications which require longer fiber lengths.

By comparing the curves of the side-emitting step index fibers ( 90 . 91 . 92 ) with those of the prior art ( 93 . 94 ) it can be seen immediately that the fibers according to the invention in useful brightness ranges (brightness values above 2) over a longer fiber length have the side emission effect than the fibers of the prior art. The decoupling efficiency correlates with the number of inlay bars, in particular by comparing the curves ( 91 ) and ( 92 ). Such fibers shine very bright over shorter distances. If longer fiber lengths are desired, a more homogeneous distribution of brightness is possible by reducing the inlay bars, such as curve ( 90 ) shows. By comparing the curves ( 90 . 91 . 92 ) of the side-emitting step index fibers according to the invention can also very well demonstrate the scalability of the side emission effect by the number of inlay bars in the preform.

Further proof of the scalability of the page emission effect by the number of inlay bars 19 in which the transmission of side-emitting step index fibers according to the invention is plotted against the wavelength of the light conducted in the fiber. The greater the transmission, the more of the injected light is conducted in the fiber. Since the measured fiber in fact had no absorption in the fiber core, the transmission is also a measure of the efficiency of the desired lateral outcoupling from the fibers. This means that the greater the transmission, the lower the effect of the side emission. A fiber which has a higher transmission accordingly shines weaker.

Curve ( 95 ) represents a side-emitting step index fiber of the present invention drawn from a preform having 15 inlay bars whose diameter was 2.8 mm. The scattering particles consisted essentially of nanofine Pt powder in all dargestellen curves. At curve ( 95 ), a size distribution was chosen such that the diameter of the scattering particles was from 500 nm to 1200 nm. Curve ( 96 ) represents a side-emitting step index fiber according to the invention, which was also drawn from a preform with 15 inlay bars of diameter 2.8 mm, wherein the size distribution of the scattering particles was chosen so that their diameter was from 150 nm to 450 nm. How to compare the curves ( 95 ) and ( 96 ), smaller scattering particles in the wavelength range up to about 560 nm cause a slightly lower transmission, in the range above about 560 nm a slightly larger transmission.

The curves ( 97 ) and ( 98 ) represent side-emitting step index fiber according to the invention, which was also drawn from a preform with 30 Inlaystäben the diameter 2.8 mm. The scattering particles consisted essentially of nanofine Pt powder. At curve ( 97 ) the diameter of the scattering particles was from 150 nm to 450 nm, at curve ( 98 ) from 500 nm to 1200 nm. At a wavelength up to about 700 nm, the fiber with smaller scattering particles (curve ( 97 )) greater transmission than the fiber with larger scattering particles (curve ( 98 )), at wavelengths above about 700 nm the ratio is reversed.

Comparison of the transmissions of the fibers drawn from preforms with 15 inlay bars (curves ( 95 ) and ( 96 ), with fibers consisting of preforms with 30 inlay rods (curves ( 97 ) and ( 98 )) shows that fibers, increasing the number of inlay bars in the preform reduces the transmission of the resulting fiber and thus increases the efficiency of lateral outcoupling from the fiber. Again, the scalability of the page emission effect can be demonstrated by choosing the number of inlay bars in the preform.

In order to produce a preferred embodiment of the side-emitting step index fiber according to the invention, a core rod ( 11 ) with fire-polished surface together with inlay rods ( 13 ) and a cladding tube pulled out to a fiber according to the described method. The core rod had a diameter of 30 mm. The cladding tube ( 12 ) had an outer diameter of 35 mm and an inner diameter of 33.5 mm. Into the cladding tube fused at one end ( 12 ) the core rod ( 11 ) and in the gap between 1 and 100 Inlaystäbe ( 13 ) of a glass of the same composition as the core rod ( 11 ), to which, however, nanofine zirconium particles or nanofine noble metal particles in the concentration range from 1 ppm to 100 ppm were added in the melt. The diameter of the inlay bars was between 0.1 mm and 2 mm. The closed end of the resulting preform ( 10 ) was applied by applying a negative pressure at the open end of the preform between core rod ( 11 ) and cladding tube ( 12 ) in the heating unit ( 20 ) retracted a known drawing system and heated to the drawing temperature. After softening the end of the preform ( 10 ) this was down from the heater ( 20 ) and thus rejuvenated into a fiber. Through this process, the inlay bars ( 13 ) softened so much that they deformed and finally a range ( 3 ) between core ( 1 ) and coat ( 2 ) of the fiber ( 22 ). By tracking the preform ( 10 ) in the heating unit ( 20 ), a continuous fiber drawing process was possible, the result being a page-emitting step index fiber of diameter from 5 μm to 300 μm and a length of several kilometers.

Can be used as materials for the core rod ( 11 ) and thus for the core ( 1 ) Glasses are used with the compositions mentioned below.

Core glass variant 1 with refractive index n ₁ of 1.65 to 1.75, containing (in mol% on oxide basis) SiO ₂ 25 to 45 Ta ₂ O ₅ 0.1 to 6 B ₂ O ₃ 13 to 25 ZrO ₂ 0.1 to 8 CaO 0 to 16 ZnO 0.1 to 8 SrO 0 to 8 CaO + SrO + BaO + ZnO> 33 BaO 17 to 35 Al ₂ O ₃ 0 to 5 La ₂ O ₃ 2 to 12

• SiO₂ 54,5 bis 65
• ZnO 18,5 bis 30
• Summe der Alkalioxide 8 bis 20
• La₂O₃ 0 bis 3
• ZrO₂ 2 bis 5
• HfO₂ 0,02–5
• ZrO₂ + HfO₂ 2,02 bis 5
• BaO 0,4 bis 6
• SrO 0 bis 6
• MgO 0 bis 2
• CaO 0 bis 2
• Summe der Erdalkalioxide 0,4 bis 6
• Li₂O 0,5 bis 3, jedoch nicht mehr als 25 Mol% der Summe der Alkalioxide SbO + ZrO₂ + HfO₂ > 58,5
• Verhältnis ZnO:Summe der Erdalkalioxide > 3,5:1

Core glass variant 2 with refractive index n ₁ of 1.65 to 1.75, containing (in mol% on oxide basis)

• SiO ₂ 54.5 to 65
• ZnO 18.5 to 30
• Sum of alkali oxides 8 to 20
• La ₂ O ₃ 0 to 3
• ZrO ₂ 2 to 5
• HfO ₂ 0.02-5
• ZrO ₂ + HfO ₂ 2.02 to 5
• BaO 0.4 to 6
• SrO 0 to 6
• MgO 0 to 2
• CaO 0 to 2
• Sum of alkaline earth oxides 0.4 to 6
• Li ₂ O 0.5 to 3, but not more than 25 mol% of the sum of the alkali oxides SbO + ZrO ₂ + HfO ₂ > 58.5
• ZnO ratio: sum of alkaline earth oxides> 3.5: 1

Core glass variant 3 with refractive index n ₁ of 1.58 to 1.65, including (in mol% on oxide basis) SiO ₂ 50 to 60 Nb ₂ O ₅ 0 to 4 B ₂ O ₃ 0 to 15 La ₂ O ₃ + Y ₂ O ₃ + Nb ₂ O ₅ 0 to 4 BaO 10 to 35 Na ₂ O 4.5 to 10 SrO 0 to 18 K ₂ O 0.1 to 1 Sr + Ba 10 to 35 Rb ₂ O 0 to 1.5 ZnO 0 to 15 Cs ₂ O 0 to 1.5 Sr + Ba + Zn 10 to 40 Rb ₂ O + Cs ₂ O 0 to 1.5 B ₂ O ₃ + ZnO 5 to 35 Sum of alkaline earth oxides 4,8-11 Al ₂ O ₃ 0.1 to 1.9 MgO 0 to 6 ZrO ₂ 0 to 4 CaO 0 to <5 La ₂ O ₃ 0 to 4 Y ₂ O ₃ 0 to 4

• SiO₂ 42 bis 53
• ZnO 30 bis 38
• Na₂O < 14
• K₂O < 12
• Na₂O + K₂O ≥ 2
• BaO < 0,9

Core glass variant 4 with refractive index including (in% by weight based on oxide)

• SiO ₂ 42 to 53
• ZnO 30 to 38
• Na ₂ O <14
• K ₂ O <12
• Na ₂ O + K ₂ O ≥ 2
• BaO <0.9

• SiO₂ 30 bis 45
• B₂O₃ < 12
• ZnO < 10
• BaO 25 bis 40
• Na₂O < 10
• K₂O < 2
• Al₂O₃ < 1
• La₂O₃ < 10

Core glass variant 5 with refractive index containing (in% by weight on an oxide basis)

• SiO ₂ 30 to 45
• B ₂ O ₃ <12
• ZnO <10
• BaO 25 to 40
• Na ₂ O <10
• K ₂ O <2
• Al ₂ O ₃ <1
• La ₂ O ₃ <10

Jacket glass variant 1 (in wt .-% on oxide basis), including SiO ₂ 70 to 78 MgO 0 to 1 Al ₂ O ₃ 0 to 10 CaO 0 to 2 B ₂ O ₃ 5 to 14 SrO 0 to 1 Na ₂ O 0 to 10 BaO 0 to 1 K ₂ O 0 to 10 F0 to 1 and essentially no Li ₂ O.

Cladding glass variant 2 (in% by weight based on oxide), including SiO ₂ 63 to 75 MgO 0 to 5 Al ₂ O ₃ 1 to 7 CaO 1 to 9 B ₂ O ₃ 0 to 3 BaO 0 to 5 Na ₂ O 8 to 20 F0 to 1 K ₂ O 0 to 6 and essentially no Li ₂ O.

• SiO₂ 75 bis 85
• Al₂O₃ 1 bis 5
• B₂O3 10 bis 14
• Na₂O 2 bis 8
• K₂O 0 bis 1

und im wesentlichen kein Li₂O und MgO.Cladding glass variant 3 (in% by weight based on oxide), including

• SiO ₂ 75 to 85
• Al ₂ O ₃ 1 to 5
• B ₂ O ₃ 10 to 14
• Na ₂ O 2 to 8
• K ₂ O 0 to 1

and substantially no Li ₂ O and MgO.

• SiO₂ 62 bis 70
• B₂O₃ > 15
• Li₂O > 0.1
• Na₂O 0 bis 10
• K₂O 0 bis 10
• MgO 0 bis 5
• CaO 0 bis 5
• SrO 0 bis 5
• BaO 0 bis 5
• ZnO 0 bis 5
• F 0 bis 1

Cladding glass variant 4 (in% by weight based on oxide), including

• SiO ₂ 62 to 70
• B ₂ O ₃ > 15
• Li ₂ O> 0.1
• Na ₂ O 0 to 10
• K ₂ O 0 to 10
• MgO 0 to 5
• CaO 0 to 5
• SrO 0 to 5
• BaO 0 to 5
• ZnO 0 to 5
• F0 to 1

• SiO₂ 60 bis 72
• B₂O₃ < 20
• Al₂O₃ < 10
• Na₂O < 18
• K₂O < 15
• Li₂O < 5
• F ≤ 1

Cladding glass variant 5 (in% by weight based on oxide), including

• SiO ₂ 60 to 72
• B ₂ O ₃ <20
• Al ₂ O ₃ <10
• Na ₂ O <18
• K ₂ O <15
• Li ₂ O <5
• F ≤ 1

• SiO₂ 72–78
• B₂O₃ 5 bis 15
• Al₂O₃ 5 bis 10
• Na₂O < 10
• K₂O < 10
• Li₂O < 5
• F ≤ 1

Jacket glass variant 6 (in% by weight based on oxide), including

• SiO ₂ 72-78
• B ₂ O ₃ 5 to 15
• Al ₂ O ₃ 5 to 10
• Na ₂ O <10
• K ₂ O <10
• Li ₂ O <5
• F ≤ 1

• SiO₂ 70–80
• B₂O₃ < 5
• Al₂O₃ < 10
• La₂O₃ < 2
• Na₂O < 10
• K₂O < 10
• ZrO₂ < 2

Jacket glass variant 7 (in% by weight based on oxide), including

• SiO ₂ 70-80
• B ₂ O ₃ <5
• Al ₂ O ₃ <10
• La ₂ O ₃ <2
• Na ₂ O <10
• K ₂ O <10
• ZrO ₂ <2

As described, all glasses used for the core glasses according to the invention can also be used for the glass of the inlay bars (FIG. 13 ) and thus as a matrix glass for the production of the scattering range ( 3 ) serve by storing scattered particles in the glass.

The glass fiber obtained in this way has excellent breaking strength. The looping tests carried out for side-emitting step fibers, which were drawn from the aforementioned glasses at a drawing temperature of 1040 ° C., gave the following values in the loop test: N _l = 15 FF = 150-450 N _l = 15 FF = 500-1200 N _l = 30 FF = 150-450 N _l = 30 FF = 500-1200 d _min [mm] 1 1 1 1 d _max [mm] 4 3 2 4 d _fraction [mm] 1.84 1.36 1.88 1.64

The scattering particles consisted mainly of Pt. N _l denotes the number of used inlay bars in the preform, FF the form factor, equivalent to the diameter of the scattering particles. FF = 150-450 thus symbolizes the presence of scattering particles in a particle size distribution with the diameters 150 nm to 450 nm. FF = 500-1200 accordingly scattering particles in a particle size distribution with the diameters 500 nm to 1200 nm. For each combination of N _l and FF 25 loop tests were carried out. d _Min indicates the smallest diameter of the loop in mm at which the fiber breaks, d _Max the maximum diameter of the loop in mm, at which a fiber break was observed. d _Break is the arithmetic mean of the individual results of each 25 loop tests in mm.

From the table it can be seen that the increase of the diameter of the scattering particles seems to lead to a slight improvement of the breaking strength due to the decrease of d _fracture . An increase in the number of inlay bars, however, seems to slightly reduce the breaking strength. However, the comparison to a glass fiber without the scattering regions according to the invention, which has a value of d _break = 1.25 mm, proves that the side-emitting step index fibers according to the invention still guarantee a very good breaking strength. Side-emitting step index fibers with non-round core diameters, as known in the art, break much earlier in the loop tests.

In addition to the side-emitting step index fibers known from the prior art, the side-emitting step index fibers according to the invention have the further advantage that they more efficiently decouple the light sideways that the effect of the side emission by the use of the inlay bars ( 13 ) is very well scalable for the applications in question and that the side-emitting step index fibers of the present invention are fire resistant due to the material of which they are made. Therefore, they can be used in areas with increased fire safety regulations. These are application areas, which are closed in particular fibers made of plastics. With the method according to the invention, fiber bundles comprising the page-emitting step index fibers according to the invention can be produced economically by machine.

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• - DE 10344205 B4 [0005, 0064]
• - DE 10344207 B3 [0005, 0064]
• - JP 9258028 A2 [0007, 0007]
• US 4466697 [0008]
• - DE 10245987 B3 [0010]
• LV 11644 B [0011]
• US 2005/0074216 A1 [0012]

Claims (51)

Side-emitting step index fiber including a photoconductive core ( 1 ) of glass with the refractive index n ₁ and a core along the fiber axis (A) enclosing transparent and / or translucent sheath ( 2 ) of glass with the refractive index n ₂ , characterized in that between the core and the cladding at least one scattering region ( 3 ), which is formed from a glass, which essentially has the refractive index n ₁ and in which scattering particles are incorporated. Side emitting step index fiber according to claim 1, characterized in that between core ( 1 ) and coat ( 2 ) at least one spread ( 3 ) which completely surrounds the core along the fiber axis (A). Side emitting step index fiber according to claim 1, characterized in that between core ( 1 ) and coat ( 2 ) at least one spread ( 3 ), which encloses the core in a partial area along the fiber axis (A) in its entirety. Side emitting step index fiber according to claim 1, characterized in that between core ( 1 ) and coat ( 2 ) at least one discrete scattering area ( 3 ) extending on a portion of the core circumference along the fiber axis (A). Side-emitting step index fiber according to claim 4, characterized in that between core ( 1 ) and coat ( 2 ) several discrete scattering regions ( 3 ), each extending on a portion of the core circumference on portions along the fiber axis (A). Side-emitting step index fiber after at least one of the preceding claims, characterized that the melting temperature of the scattering particles larger is the melting temperature of the glass in which it is stored are. Side-emitting step index fiber after at least one of the preceding claims, characterized that the scattering particles have a diameter of 10 nm to 5000 nm, preferably from 100 nm to 1200 nm. Side-emitting step index fiber according to at least one of the preceding claims, characterized in that the scattering particles SiO ₂ and / or SiN and / or BaO and / or MgO and / or ZnO and / or Al ₂ O ₃ and / or AlN and / or TiO ₂ and or ZrO ₂ and / or Y ₂ O ₃ and / or the metals of these oxides alone and / or BN and / or B ₂ O ₃ and / or Ru and / or Os and / or Rh and / or Ir and / or Ag and / or Au and / or Pd and / or Pt and / or diamond-like carbon and / or glass-ceramic particles. Side-emitting step index fiber after at least one of the preceding claims, characterized that the concentration of scattering particles in the scattering range of 10 ppm to 1000 ppm, preferably from 20 ppm to 100 ppm. Side-emitting step index fiber after at least one of the preceding claims, characterized that the thermal expansion coefficient of the core glass is larger is the thermal expansion coefficient of the cladding glass. Side-emitting step index fiber according to at least one of the preceding claims, characterized in that the diameter of the core ( 1 ) of 10 .mu.m and 150 .mu.m, the at least one scattering range ( 3 ) has a thickness of 100 nm to 2 μm and the cladding ( 2 ) is from 500 nm to 2 μm thick. Fiber bundles ( 23 ) comprising a multiplicity of glass fibers and an outer shell completely enclosing the plurality of glass fibers along the fiber bundle axis ( 24 ), characterized in that the fiber bundle ( 23 ) a plurality of side-emitting step index fibers ( 22 ) according to at least one of the preceding claims and the outer jacket ( 24 ) is transparent and / or translucent. Sheet comprising a plurality of page-emitting step index fibers ( 22 ) according to at least one of the preceding claims. A fabric according to claim 13, wherein the side-emitting step index fibers ( 22 ) are arranged substantially parallel to each other. The fabric of at least one of claims 13 to 14, wherein the side-emitting step index fibers are supported on a support member (10). 71 ) are fixed and so a composite element of support element ( 71 ) and side-emitting step index fibers. The fabric of at least one of claims 13 to 14, wherein the side-emitting step index fibers are formed into a support member (12). 71 ) are embedded and so a composite element of carrier element ( 71 ) and side-emitting step index fibers. The sheet according to at least one of claims 13 to 15, wherein the side-emitting step index fibers with each other and / or with the carrier element ( 71 ) are fixed by sewing. The sheet according to at least one of claims 13 to 15, wherein the side-emitting step index fibers with each other and / or with the carrier element ( 71 . 72 ) are glued. Fabrics after at least one of Claims 13 to 18, wherein the carrier element transparent and / or translucent. The sheet according to at least one of claims 13 to 19, wherein the composite element of carrier element ( 71 ) and side-emitting step index fibers with a stabilizing element ( 72 ) connected is. A fabric according to claim 20, wherein the stabilizing element ( 72 ) is arranged so that the side-emitting step index fibers between a surface of the support element ( 72 ) and a surface of the carrier element ( 71 ) are located. The sheet according to at least one of claims 15 to 21, wherein the side of the step-emitting index fibers facing side of the support element ( 71 ) and / or the stabilizing element ( 72 ) is adapted to reflect the light emitted from the side emitting step index fibers. Fabrics after at least one of Claims 13 to 22, wherein the sheet about Measures to connect at least one LED as the light source has. Preform 10 ) for producing a side-emitting step index fiber comprising a core rod ( 11 ) of a glass with the refractive index n ₁ and a cladding tube ( 12 ) of a glass with the refractive index n ₂ , wherein the cladding tube ( 12 ) the core rod ( 11 ) along the core rod axis, characterized in that between core rod ( 11 ) and cladding tube ( 12 ) substantially parallel to the core rod axis at least one inlay rod ( 13 ) is arranged from a glass, which essentially has the refractive index n ₁ and in which scattering particles are embedded. Preform 10 ) according to claim 24, characterized in that between core rod ( 11 ) and cladding tube ( 12 ) from 5 to 100 inlay bars ( 13 ) are arranged in essences parallel to the core bar axis. Preform 10 ) according to at least one of claims 24 to 25, characterized in that the diameter of the inlay bars ( 13 ) from 0.2 mm to 2 mm. Preform 10 ) according to at least one of claims 24 to 26, characterized in that the scattering particles have a diameter of 10 nm to 2000 nm, preferably from 100 nm to 1200 nm. Preform 10 ) according to at least one of claims 24 to 27, characterized in that the scattering particles consist essentially of Al ₂ O ₃ and / or TiO ₂ and / or Ru and / or Os and / or Rh and / or Ir and / or Ag and / or Au and / or Pd and / or Pt. Preform 10 ) according to at least one of claims 24 to 28, characterized in that the concentration of the scattering particles in the at least one inlay bar ( 13 ) from 10 ppm to 1000 ppm, preferably from 20 ppm to 100 ppm. Method for producing a page-emitting step index fiber, comprising the method steps - providing a core rod ( 11 ) of a glass with the refractive index n ₁ , Arranging a cladding tube ( 12 ) of a glass with the refractive index n ₂ , so that the core rod ( 11 ) within the cladding tube ( 12 ) and a Perform ( 10 ), - heating the preform ( 10 ), - removing the preform ( 10 ) to a glass fiber ( 22 ), characterized in that to obtain the preform ( 10 ) at least one inlay bar ( 13 ) is arranged from a glass with substantially the refractive index n ₁ parallel to the core rod axis, wherein in the glass of the inlay rod ( 13 ) Scattered particles are stored. A method according to claim 30, characterized in that when pulling out the preform ( 10 ) at least one inlay bar ( 13 ) with the core rod ( 11 ) merges, so that a discrete scattering area is formed which extends at least on a partial circumference of the fiber core (FIG. 1 ) extends along the fiber axis (A). Method according to at least one of claims 30 to 31, characterized in that the preform ( 10 ) a plurality of inlay bars ( 13 ), which when pulling out the preform ( 10 ) with both the core rod ( 11 ) as well as merge together, so that at least one discrete scattering area ( 3 ) is formed, at least on a partial circumference of the fiber core ( 1 ) extends along the fiber axis (A). Method according to claim 30, characterized in that the preform ( 10 ) a plurality of inlay bars ( 13 ), which when pulling out the preform ( 10 ) with both the core rod ( 11 ) as well as merge together so that a spread ( 3 ) forming the fiber core ( 1 ) completely encloses along the fiber axis (A). Method according to at least one of claims 30 to 33, characterized in that to the preform ( 10 ) is applied when removing negative pressure. Method according to at least one of claims 30 to 34, characterized in that for the cladding tube ( 12 ) a glass is used whose thermal expansion coefficient is smaller than the thermal expansion coefficient of the glass used in the core rod ( 11 ). Method according to at least one of claims 30 to 35, characterized in that a plurality of preforms ( 10 ) side by side in a heating unit ( 20 ) of a multi-fiber drawing machine and several side-emitting step fibers ( 22 ) are pulled out simultaneously in a multi-fiber drawing machine so that a fiber bundle ( 22 ) containing side-emitting step index fibers. Method according to claim 36, characterized in that around the fiber bundle ( 22 ) an outer shell of a transparent and / or translucent plastic is extruded. Method according to claim 36, characterized in that the fiber bundle ( 22 ) is surrounded with glass fibers which form an outer non-combustible transparent and / or translucent sheath around the fiber bundle. Use of at least one page-emitting step index fiber according to at least one of claims 1 to 11 together with other optical fibers and / or other side-emitting step index fibers at least one of claims 1 to 11 in a fiber bundle, which of an outer transparent and / or surrounded by translucent coat. Use according to claim 39 for the accent lighting of interiors and / or facades ( 51 ) in architecture. Use according to claim 39 for the accent lighting of interiors of vehicles ( 30 . 31 . 32 . 33 ), in particular of automobiles, aircraft, ships and / or trains. Use according to claim 41 as part of interior linings ( 30 ) of vehicles, in particular automobiles, aircraft, ships and / or trains. Use according to claim 39 as part of furniture, in particular vehicle seats ( 32 . 33 ), Residential landscapes and / or kitchens. Use according to claim 39 as component ( 41 . 45 ) of a headlamp ( 40 ), in particular of Vehicle headlights. Use according to claim 44 in automobile headlamps ( 40 ), whereby through the fiber bundle ( 41 . 45 ) containing the side-emitting step index fiber, the light is extracted from point sources such as LEDs. 46. Use according to claim 39 for contour lighting of vehicles, in particular automobiles, aircraft, ships and / or trains. Use according to claim 39 for illuminating runways ( 61 . 62 ) for aircraft. Use of at least one page-emitting step index fiber according to at least one of claims 1 to 11 together with other optical fibers and / or other side-emitting step index fibers at least one of claims 1 to 11 in a sheet. Use of a fabric after at least one of claims 13 to 23 as a lighting fixture. Use according to claim 49 for backlighting of displays. Use according to claim 49 for ambient lighting in vehicle interiors, in particular motor vehicles, aircraft and ships. Use according to claim 49 for ambient lighting in architecture.