LIGHT BULB HAVING SURFACES FOR REFLECTING LIGHT PRODUCED BY ELECTRONIC LIGHT GENERATING SOURCES Field of the Invention The present invention relates to light bulbs. More specifically, the invention relates to a lighting element for use in light bulbs. The lighting element is comprised of electronic light generating sources, such as light emitting diodes (LED's), which are mounted on a flexible form that is configured to produce increased luminescence and light dispersion provided by backlit LED's. Problem Light emitting diodes are constructed with semi-conductor material allowing a conversion of electricity into light. Incandescent lighting, on the other hand, creates light by heating a filament, such as a tungsten filament Fluorescent lighting creates light by bombarding gaseous mercury with electrons. Although the light generated by bombardment of the mercury is ultraviolet and invisible, the UV light engages with a white phosphor on the inside of the glass enabling the light to be converted to white light so that it is visible to the human eye. The LED light sources are actually more desirable than other forms of lighting since they provide a more natural color of light and, hence, they are supenor for many applications. LED bulbs can be designed to generate light in a variety of colors In fact, it has been found that LED light sources can be used for area lighting such as desktop work areas, hallways and pathways and the like. It would be quite advantageous to use LED light bulbs, as opposed to the more conventional incandescent lamps. Unfortunately, LED bulbs do not have a wide degree of light dispersion. Unlike incandescent bulbs, LED's do not generate a substantial amount of heat which oftentimes must be dissipated and can sometime lead to burn injuries. Moreover, conventional incandescent lamps have a limited life compared to electronic forms of lighting and associated with the long life of an electronic light source is the fact that it would not be necessary to constantly change the light source when the bulb burned out. Thus, the LED and other electronic light bulbs provide a rather significant advantage over conventional lamps. Attempts to improve the dispersion qualities of LED's used in illuminating devices, such as blinkers and warning signals, by using curved reflective surfaces to direct the light produced by the LED's outward in a straight path, which does improve the light paths from the LED's but it doesn't improve the dispersion of the light. Other applications attempt to improve the dispersion from LED's by applying a reflective material is disposed on the individual LED encapsulant surface that is disposed opposite the LED die surface. Again, this arrangement reflects light generally incident to the encapsulant possessing the reflective mateπal and not in a true omni directional fashion. Another attempt to increase the dispersion of light produced by LED's is to arrange a flexible substrate into a semi-sphencal or circular arrangement or shape This arrangement then provides lighting generally perpendicular to the flexible substrate at any given point, but does not provide omni directional
lighting. Other techniques include using concave reflector disposed over LED's which concentrates, instead of dispersing the light emitted from the LED's. It would therefore be desirable to provide a light bulb with organic or inorganic light sources capable of generating a substantial quantity of light which necessitates the use of many individual light elements and also to provide a wide angle of dispersion of the light generated from that bulb. Information relevant to attempts to address these problems can be found in U.S. Patent Nos
5,136,483 issued August 4, 1992 to Schδniger et al.; 6,674,096 issued January 6, 2004 to Sommers;
5,585,783 issued December 17, 1996 to Hall; and 5,782,553 issued July 21, 1998 to McDermott.
However, each one of these references suffers from one or more of the following disadvantages: lack of functionality and limited light dispersion properties
Solution In accordance with the present invention, there is provided an LED light bulb that uses a plurality of electronic light emitting elements, such as conventional light emitting diodes (LED's), and which are all mounted within a base. The LED's are thereupon mounted within a housing which may be formed of a plastic or synthetic resin mateπal as, for example, a suitable polyester resin, e.g. an epoxy type resin.
The housing is typically funnel shaped and has a shape somewhat similar to that of a conventional incandescent light bulb. However, the light bulb descnbed in this form, but without the modification offered by the present invention, would result in about 90 degree dispersion, and this is often insufficient for general lighting purposes. In the light bulb of the present invention, the interior surface of the housing and, particularly, the funnel shaped portion thereof is provided with a reflective surface. In this way, some light which does happen to reflect from the LEDs can remain in the housing and reflect back and forth in the housing until it exits through the substrate and optical opening of the housing This reflected light would tend to have a wider angle of dispersion since it has been reflected within the housing and would exit at an angle relative to the axis of the housing. In addition to the foregoing, there is also provided additional LEDs which are located on the inteπor surface of the lens or cap of the housing. It is also possible to use a plurality of light emitting diodes on the intenor of the lens, in addition to those which cause the generation of light on the exterior surface of the lens. This additional row of LEDs would cause light to be generated in the interior of the housing and purposely reflected until it exits through the lens. In this way, the light will reflect at various angles and there will therefore be provided a wide angle of light dispersion. It is possible to adjust the angle of dispersion of the light by adjusting the angle of taper of the reflector. Moreover, by adjusting the length of the light bulb from the base to the lens and adjusting the angle of taper of the light bulb, it is also possible to increase the amount of reflection and, hence, it is possible to adjust the amount of light dispersion. Thus, one of the advantages of the present invention is the fact that there can be a controlled amount of light dispersion. This was difficult to accomplish with
conventional light sources, such as incandescent lamps and fluorescent lamps. Another one of the unique advantages of the present light bulb is the fact that the circuit board upon which the LEDs are mounted can be located at or adjacent to the lens of the bulb. In this way, the light emitting diodes could be mounted directly to the printed circuit board itself and this combination becomes an integral part of the LED light bulb. Yet another unique advantage of the present light bulb is the use of an optical tuning element to control the dispersion of the light emitted from the light bulb. Specifically, the optical tuning element be shaped and include reflective portions, opaque portions, and transparent portions to control the reflection and dispersion of the light emitted from the light bulb. It is understood, however, that the present light bulb could be used with any of a variety of light sources and, particularly, light sources which are electronically activated or generated. As an example, in recent years there have been proposals to produce light sources using various known inorganic materials and, for that matter, some organic materials. Thus, the present light bulb is applicable with each of these light generating elements which are all electronically energized or operated. For purposes of the present application, however, the invention will be described in terms of light emitting diodes as the light generating elements, since they are the preferred form. However, it is to be understood that the invention is not so limited. This present invention thereby provides a unique and novel LED light bulb constructed so as to provide a wide angle of light dispersion and also a controlled light dispersion. The light bulb includes a plurality of LED's arranged to provide backlighting towards a reflective inside wall of the housing that is then reflected back through the transparent substrate and out an optical opening in a wide dispersion, omni directional pattern. The dispersion of the light is further controlled by an optical tuning element that includes reflective portions, opaque portions, and transparent portions located thereon for further providing light dispersion in an omni directional pattern. The light bulb thereby fulfills all of the above-identified objects and other objects which will become more fully apparent from the consideration of the forms in which it may be embodied. One of these forms is more fully illustrated in the accompanying drawings and described in the following detailed description of the invention. However, it should be understood that the accompanying drawings and this detailed description are set forth only for purposes of illustrating the general principles of the invention.
Brief Description of the Drawings Figure 1 illustrates a cross-section view of a light bulb having wide angle dispersion material incorporated therein and backlit light emitting elements in accordance with the invention; Figure 2 illustrates an expanded cross-section of a side wall and incorporated crystalline particulate material of a light bulb in accordance with the invention; Figure 3 illustrates a cross-section view of another embodiment of a light bulb having wide angle
dispersion material incorporated therein and backlit light emitting elements in accordance with the invention; Figure 4 illustrates a cross-section view of another embodiment of a light bulb housing having a wider angle side wall in accordance with the invention; Figure 5 illustrates a cross-section view of another embodiment of a light bulb having wide angle dispersion material incorporated therein in accordance with the invention; Figure 6 illustrates a top-section view of a light bulb substrate of the Figures 1 - 4 having wide angle dispersion material incorporated therein in accordance with the invention; Figure 7 illustrates a cross-section view of another embodiment of a light bulb including an optical tuning element; Figure 8 illustrates in block flow diagram form a process for dispersed light from a lighting device; and Figure 9 illustrates in block flow diagram form a process for manufacturing a light bulb having light generating sources. Detailed Description of the Drawings Referring now in more detail and by reference to Figure 1, there is provided an embodiment of a light bulb 100 including a housing 102 having a somewhat conically shaped side wall 104 having an inside surface 115 and which is provided at one end with a base 106 such as a conventional Edison base and which is provided at the other end with a transparent or translucent end cap 114. The base 106 is of the type which is used in a conventional incandescent light socket or other conventional lighting fixture socket, such as used in fluorescent lighting fixtures and the like. A cavity 116 is defined by the area between the side wall 104 and the transparent or translucent end cap 114. Mounted within the cavity 116 of the housing 102 is a support 110 for supporting a substrate 108 having a plurality of light emitting elements 112. The entire support 110 and light emitting elements 112 are covered partially or fully by the end cap 114. In the embodiment as shown, it should be understood that it is possible to eliminate the end cap 114 and use the substrate 108 as the end cap 114 for the housing 102. The substrate 108 is preferably transparent and may adopt the form of a printed circuit board. In this embodiment, a semi -hemispherical shaped insert 118 having an inside surface 122 is inserted into the housing 102 to provide a base for the support 110 and the inside surface 122 for reflecting light that enters the cavity 120 of the insert 118. An insert cavity 120 is defined by the area between the insert 118 and the translucent end cap 114. The substrate 108 has a first surface 136 and a second surface 134 and has an outside peripheral edge 132, generally defined as the circumferential outer perimeter of the substrate 108, which can be connected to a corresponding area of the housing 102, as described further below. The surfaces 136 and
134 are substantially planar, however, they may be formed to a desired shape. Attached to the first
surface 136 is the plurality of light emitting elements 112 as descπbed above. These light emitting elements 112 emit light toward the end cap 114. In addition to these light emitting elements 112, are light emitting elements 130 connected to the second surface 134 of the substrate 108. These light emitting elements 130 emit light substantially toward the inside wall 122 of the insert 118. In one aspect of the present light bulb, one or two rows of light emitting elements 130 are located around the outer peripheral edge 132 of the second surface 134. In another aspect of the present light bulb, the light emitting elements 130 may be located elsewhere on the second surface 134 of the substrate 108. Referring to Figure 2 is an expanded view of a portion of the insert 118 depicting a crystalline particulate material mcoφorated into the inside surface 122. As can be seen from Figure 2, the crystalline particulate mateπal 124 is incoφorated on the inside surface 122 of the insert 118 and also within the material comprising the insert. In one aspect of the present light bulb, the crystalline particulate matenal
124 can be mixed and formed with the housing 102, substrate side wall 104, inside surface 115, end cap
114, substrate 108, and support 110. In another aspect of the present light bulb, the crystalline particulate material 124 can be applied with adhesives or the like to the surfaces of the light bulbs after they have been formed or assembled. Referring to Figure 3 is another embodiment 150 of a light bulb including similar parts as those previously described in Figure 1, including a housing 102, a side wall 104 having an inside surface 115, a base 106, a cavity 116, an end cap 114, a plurality of light emitting elements 112, a substrate 108 having a first surface 136 and a second surface 134 and an outer peripheral edge 136. In this embodiment, the substrate 108 may be mounted on and supported at the outer peripheral edge 132 of the housing 102. As can be seen in Figure 3, light emitting elements 130 are attached to the second surface 134 of the substrate 108 similarly to those depicted in Figure 1. In addition, the light bulb 150 includes crystalline particulate material 124 incoφorated withm the side wall 104 of the housing 102 Referring to Figures 1 and 3, it is important to introduce the crystalline particulate mateπal 124 in the side wall 104 including the inside surface 115 and also the end cap 114 of the present light bulb. These light emitting elements 130 effectively backlight or produce light on the cavities 120 and 116 which is then reflected by the crystalline particulate mateπal 124 incoφorated in the inside surfaces 122 and 115, which can also be a mirrored surface mateπal. After reflection on the inside surfaces 122 and
115, this light will then exit through the transparent substrate 108 then through the end cap 114. In this way, there is a wide degree of dispersal of light. In addition, the support 110 may also comprise a mateπal including particulate matter In addition, electrical connectors 128 can be routed through the support 110 or through or along the side walls 104 of the housing 102 Electricity supplied to these electπcal connectors 128 can be AC or DC, in the case of AC the necessary circuitry 126 may be located in the base 106 for converting the AC power to DC power. This circuitry 126 may include resistors, rectifying diodes, and Zener diodes. Rectifying diodes convert AC to DC, should the power source to the LED's be AC. Rectifying diodes are not needed when the power supply is DC. In another aspect of the
present light bulb, the circuitry may be located elsewhere, such as in the support 110 and be covered with a cover plate (not shown) if desired, which may be transparent in construction. One of the unique aspects of the present light bulb is that in order to obtain the DC to AC conversion which is desired, a semiconductor rectifier 109 is used. In this aspect, the semiconductor rectifier 109 is located on substrate 108. In this aspect of the present light bulb, it is formed of a semiconductor matenal, such as silicon which may include a metallic oxide, and does effectively rectify the cmrent in order to achieve an AC current. In this respect, it is believed that the applicant is the first to actually use a semiconductor rectifier in a light emitting element light bulb. Referring to Figure 4, another embodiment 200 of the present light bulb 202 is depicted in which the side wall of the housing 204 is located at a more obtuse angle with respect to the base 106. In this way, the amount of reflectivity and light dispersion can then be controlled. This is one of the unique advantages of the present light bulb in that it is now possible to literally control the amount of light dispersion. By increasing the angle of the comcal shaped portion of the side wall 204, it is possible to obtain a greater degree of light incidence and angle of reflection. Hence, there will be a greater angle of light dispersion. In fact, there would appear to be a direct correlation between the angle of the side wall 204 with respect to the amount of light dispersion. Referring to Figure 5, is another embodiment 250 of a light bulb including a housing 252 including a somewhat comcally shaped side wall 254 with a flared end having an inside surface 266 and which is provided at one end with a base 256 and a transparent or translucent end cap 262 at the other end. A cavity 264 is defined by the area between the side wall 254 and the end cap 262. Mounted within the cavity 264 of the housmg 252 is a substrate 258 having a first surface 270 and a second surface 268 having a plurality of light emitting elements 112 connected to the first surface 270 and a plurality of light emitting elements 130 connected to the second surface 268. Light bulb 250 may further include a support (not shown) located within the cavity 264 for supporting the substrate 258, similar to the support 110 as depicted in Figure 1. Similarly as described with reference to the other embodiments of the light bulb, it is important to introduce crystalline particulate material 124 in the side wall 254 including the inside surface 266 and also the end cap 262. The light emitted from the light emitting elements 130 will reflect off inside surface 266 and back through the transparent substrate 258 and then through the end cap 262. In addition, if a support is used with this embodiment, the support may also comprise a material including crystalline particulate material 124. As descnbed with reference to Figures 1 and 3, one aspect of the present light bulb provides for the light emitting elements 130 to be arranged a single or double row around the outer peripheral edge 272 of the second surface 268 of the substrate 258. In another aspect, the light emitting elements 130 are arranged elsewhere on the second surface 268 to provide light toward the inside surface 266 to be reflected back through the substrate 258 and then through the end cap 262 to produce a wide angle dispersion of light.
Referring to Figure 6, is a top view 300 of an end cap 114, which is similar to the cap 262. As can be seen in Figure 6, a plurality of light emitting elements 112 are grouped together on substrate 108, which is similar to substrate 258. It is noted that in some aπangements of the light emitting elements 112, gaps 502 can be seen in the substrate 108 where light comes through after being reflected within the cavities 116, 120, and 264. Referring to Figure 7, is another embodiment 350 of the present light bulb having a housing 352 and many similar elements or parts as descnbed in Figure 1, including a side wall 104, a base 106, electrical connectors 128, insert cavity 120, support 110, insert 118, substrate 108 having a first surface 136 and a second surface 136, and a plurality of light emitting elements 112 connected to the first surface 136. In this embodiment, instead of an end cap 114, the light bulb 350 includes an optical tuning element 354 disposed substantially or wholly over the plurality of light emitting elements 112. The optical tuning element 354 preferably includes opaque portions 358 and mirrored portions 360 In this aspect of the present light bulb, the first surface 136 of the substrate 108 is provided with a mirrored surface 356 or a coating of substantial reflectivity. Disposed over the first surface 136 of the substrate 108 and the light emitting diodes 112 earned thereon is the optical tuning element 354. In one aspect of the present light bulb, the optical tuning element 354 is located under an outer lens 362 if the latter is employed Moreover, the optical tuning element 354 is provided with opaque areas 358 and transparent areas 364. Thus, light generated from several of the light emitting elements 112 will be reflected off of the opaque portions 358. These opaque portions 358 may also include mirrored portions 360. In this way, light can be reflected off of the miπored surface 356 on the substrate 108 and also reflected off of the mirrored portions 360. Light which reflects off of the mirrored portions 360 and the mirrored surface 356 will then pass through the transparent areas 364 of the optical tuning element 354 and out through the lens 362 in a wide angle of dispersion. In this aspect of the present light bulb, it is not necessary to use a crystalline particulate mateπal
124 or mirrored surface on the inside surface 122 of the insert 118. In another aspect of the present light bulb, crystalline particulate matenal 124 or mirrored surface could also be employed with the light emitting elements 130 if desired for additional light dispersion. In another aspect of the present light bulb, the aπangement described above in reference to Figure 7 may be employed without a support 110 or insert 118, similar to light bulb 150. In one aspect of the present light bulb, the individual parts herein descnbed can be molded or formed individually and then later assembled. In another aspect of the present light bulb, some portions of the light bulbs 100, 150, 200, 250, and 350 can be molded or formed together, while other parts are molded or formed individually and then later assembled. In one aspect of the present light bulbs 100, 150, 200, 250, and 350 the housings 102, 252, 202, and 352; end caps 114, 262, and lens 362; support 110, and substrates 108, 258, and 206 are molded or formed with a mixture of moldable or formable resin
including a crystalline particulate material 124. In one aspect of the present light bulb, end caps 114, 262, and lens may comprise different shapes, forms, thicknesses, patterns, and etchings to provide further dispersion of the light from the light bulbs 100, 150, 200, 250, and 350. In the formation of the housings 102, 252, 202, and 352; end caps 114, 262, and lens 362; support
110, and substrates 108, 258, and 206, it is important to use materials that are capable of incoφorating a particulate matter during the preparation of the materials prior to forming, molding, or shaping. In another aspect of the present light bulb, it is important to use materials that after being formed are capable of incoφorating particulate matter with the use of adhesives or other fixture means. Many resins are known and presently used to form these parts, including glass, plastics, polycarbonates, polymers, copolymers and suitable epoxies and acrylics. In another aspect of the present light bulb, a resin, such as acrylonitrile-butadiene-styrene, is effective for forming some or all of these described parts. In one aspect of the present light bulb, the housing 102, 252, 202, and 352 is preferably formed of a resinous material. However, if desired, it could be formed of glass and fitted to the base 106 with the end caps 114, 262, and lens 362 then secured to the housing 102, 252, 202, and 352. The light emitting elements 112 and 130 are generally light emitting diodes (LED's), but may be other types of diode lights, such as laser diodes and wide band gap LED's. Generally, these typical LED's are normally constructed using standard AlInGaN or AlInGaP processes and include a LED chip or die mounted to a reflective metal dish or reflector that is generally filled with a transparent or semi- transparent epoxy, thus encapsulating the LED chip. The epoxy or encapsulant serves the puφoses of reducing the total internal reflection losses and sealing the LED chip or die. Lensless LED's have the encapsulant removed from the reflective metal dish, thus exposing the diode. The present LED light bulb provides use of both of these types of LED's. The LED's used in the present LED light bulb provide a wide functional coverage according to the specific LED's employed with the LED light bulb. Any color of LED's can be used with the present LED light bulb, colored LED's such as red (R), blue (B), and green (G) can be use in addition to white (W) with the present LED light bulb to accommodate the desires of the user. For example, mood lighting can be achieved by combining the desired colored LED's together in the LED light bulb. The end desired light product can be achieved by using the RGB W LED's to accomplish the desired lighting. By way of illustration, if a 3,700 Kelvin color is desired, the mix of the LED's would be 50 red, 27 green, and 23 blue to achieve this color. In this aspect of the LED light bulb, a designed housing 102, 252, 202, and 352 incoφorating the proper microoptics, such as finishes or thin films, mixes the color to provide the desired end product. The number, aπangement, and color selection of the LED's on the formed substrate 108 and 258 creates a flexible LED light bulb that can meet the desired lighting requirements of a given situation. The LED's can be color shifted as well to increase the flexibility of the end product LED light bulb. The color can be adjusted as well to add greater flexibility. Generally, any number and color of
LED's can be used to provide the desired lighting requirements. By way of example, a department store may desire to have more of a full-spectrum lighting aπangement for its cosmetic counters. In this example, several different LED's will be used to provide a light with a fuller spectrum with optimal color rendering than may be needed for lighting a hallway or other room in a building. In addition to the lighting function provided by the LED light bulb, other functions can be provided by the LED light bulb, either independently or in concert with the lighting function. The present invention provides exemplary methods for producing a tuned dispersed light from the present light bulb. Figure 8 illustrates a block flow diagram of an exemplary method 400 in accordance with the present light bulb. In step 402, a housing 102, 202, 252, and 352 is provided generally including a base 106 and 256, however, the base 106 and 256 at this step may or may not be attached to the housing 102, 202, 252, and 352. The housing 102, 202, 252, and 352 is formed using a transparent, semi- transparent, or translucent material and is shaped to a desired shape. In addition, the housing 102, 202, 252, and 352 may be provided in a single piece or separate pieces to be attached together later in the process by adhesives or other fixture means. The base 104 and 256 also generally includes a formed socket a socket piece for inserting into a standard socket, Edison-style or standard electncal socket or connection Step 402 also includes providing housings 102, 202, 252, and 352 having optimized shapes and lengths to achieve the desired light dispersion characteristics from the present light bulb. This step includes providing housings 102, 202, 252, and 352 including a side wall 104, 204, and 266 having desired shape, form, and angle to provide the desired dispersion of light. In Step 404, a plurality of light emitting elements 112 and 130 are supported and connected on a substrate 108 and 258. Step 404 also comprises connecting the light emitting elements 112 and 130 to the necessary electncal connectors 128 and connecting those electncal connectors 128 to the base 106. Step 404 further compnses orienting the plurality of light emitting elements 112 and 130 to provide the desired dispersion of light. In step 406, the light emitting elements 112 and 130 are energized by supplying electncity, either DC or AC to the plurality of light emitting elements 112 and 130. In step 408, the light emitted from the light emitting elements 112 and 130 is tuned to produce a light of desired dispersion characteπstics. This tuning step includes providing an optical tuning element 354 that may also include opaque portions 358, mirrored portions 360, and transparent portions 364. The number and area of these portions 358, 360, and 364 are determinable by the desired amount of light dispersion to be provided by the present light bulb. In step 410, other tuning techniques in addition to those originally selected in step 408 are employed. The present invention also provides preparation a method 450 for manufactuπng a light bulb having light generating sources. Figure 9 illustrates a block flow diagram of an exemplary method 450 in accordance with the present light bulb 100, 150, 200, 250, and 350. In step 452, a housing 102, 202, 252, and 352 is formed using matenals and techniques herein described. In step 454, a substrate 108 and 258
is formed using materials and techniques herein described. In step 456, electrical connectors 128 are incoφorated into the substrate 108 and 258 in regions where the light emitting elements 112 and 130 are to be connected to the substrate 108 and 258. In step 458, light emitting elements 112 and 130 are connected to the electrical connectors 128 and to the substrate 108 and 258. These connections can be made by those methods commonly known in the arts, such as soldering or the like. In step 460, the substrate 108 and 258 is mounted to the housing 102, 202, 252, and 352. This step can include mounting a support 110 if one is used, or mounting the substrate 108 and 258 to the housing 102, 202, 252, and 352, or both. In step 462, the electrical connectors 128 are connected to the base 106 and the substrate 108 and 258. When an semiconductor rectifier 109 is used, then the electrical connectors 128 are connected to the semiconductor rectifier 109 which is then connected to the substrate 108 and 258. If other electrical circuitry is employed with the present light bulb, then it is connected to the electrical connectors 128 in order to provide the coπect circuitry desired. In step 464, the light emitting elements 112 and 130 and the optical opening is partially or wholly encapsulated by the optical tuning element 354 or end caps 114 and 262. The distance between the optical tuning element 354 and end caps 114 and the optical opening partly depends on whether the light emitting elements 112 and 130 have lenses or not and the desired dispersion to be provided by the light bulb 100, 150, 200, 250, and 350. Although there has been described what is at present considered to be the prefeπed embodiments of the present invention, it will be understood that the invention can be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The present embodiments are, therefore, to be considered in all aspects as illustrative and not restrictive. The scope of the invention is indicated by the appended claims rather than the foregoing description.