DE102015223024A1 - Laser distance measuring device - Google Patents

Abstract

The invention relates to a laser range finding device (10, 10 ', 10 "), in particular a hand-held laser range finder (10', 10"), which is provided by a device for measuring laser distance with at least one transmitting device (28) for emitting laser radiation (30). a receiving optical system (56) for receiving laser radiation (30 ') returning from a remote object (34) and at least one detector device (22) for detecting received laser radiation (30'), the laser radiation (30) being generated by means of a projection device (20) the transmitting device (28) an angle range α (46) is transmitted periodically sweeping, so that a projected laser line (52) on the remote object (34) can be displayed. According to the invention, the receiving optics (56) of the laser distance measuring device (10, 10 ', 10' ') comprise laser radiation (30') from an angular range γ (60) for detecting facet optics (62) projecting onto the detector device (22). Further, a method for determining a distance on a surface of a remote object (34) by means of the laser range finder (10, 10 ', 10 ") is proposed.

Description

State of the art

The present invention relates to a laser rangefinder, in particular a hand-held laser rangefinder, according to the preamble of claim 1.

There are already proposed generic laser distance measuring devices, in which laser radiation by means of a projection device of a transmitting device an angular range is transmitted periodically sweeping. Such laser rangefinders are for example in DE 10 0163 09 A1 , in DE 10 2011 005 277 A1 and DE 10 2011 089 325 A1 been proposed.

Disclosure of the invention

The proposed laser range finder, in particular a handheld laser range finder, is based on a laser rangefinder with at least one transmitting device for emitting laser radiation, receiving optics for receiving from a remote object returning laser radiation and at least one detector device for detecting received laser radiation, wherein the laser radiation by means of a Projection device of the transmitting device is an angle range α periodically scanned out, so that a projected laser line on the remote object can be displayed. According to the invention, the receiving optics has a laser radiation from an angular range γ for detecting facet optics projecting onto the detector device.

In one exemplary embodiment, the laser rangefinder is a hand-held measuring device that can be guided only with the hands, preferably with one hand, without the aid of a transport device and / or a holding device. In particular, the hand-held laser rangefinder is provided to be at least guided by a user by hand in a measuring operation, preferably carried, particularly preferably held. For this purpose, the total mass of the laser rangefinder is in particular less than 2 kg, preferably less than 1 kg, more preferably less than 500 g. Furthermore, in a preferred embodiment of the laser rangefinder, all the components of the measuring device are accommodated in a housing substantially enclosing the components. In particular, the length of the longest side of this housing is less than 30 cm, advantageously less than 20 cm, particularly advantageously less than 15 cm. For example, in one example of an application, the hand-held laser range finder can be used to measure objects or interiors in crafting activities.

In an alternative or additional embodiment, the laser range finding device according to the invention can also be realized as a stationary device and / or used as a stationary device.

In one embodiment of the laser range finding device, the laser range finding device according to the invention is used in a vehicle, in particular in a motor vehicle. In such a designed embodiment, the integrated laser rangefinder can be used preferably for measuring distances during navigation of the vehicle and / or in connection with a safety device of the vehicle, in particular in connection with a brake device.

The term "intended" should be understood to mean in particular "programmed", "designed" and / or "equipped". By "providing" an object for a particular function, it should be understood, in particular, that the object fulfills and / or executes this particular function in at least one application and / or operating state or is designed to perform the function.

The transmitting device of the laser distance measuring device for emitting laser radiation has at least one light source, preferably in the form of a laser, a semiconductor laser or a laser diode, in particular temporally modulated light, preferably laser radiation, in the direction of a distant object - synonymous hereinafter: in the direction of a Target object - sends out. A temporal modulation can take place here continuously and / or periodically, for example sinusoidally. Likewise, light pulses can be emitted in the direction of a target object. Furthermore, pulse trains, such as non-periodic such as e.g. in the form of so-called pseudo-noise pulse sequences, are sent out. In particular, the transmitting device can also comprise a plurality of radiation-emitting devices of uniform or nonuniform nature, in particular a plurality of laser light sources.

In one embodiment, the laser radiation may be in a spectral wavelength range visible to the human eye, ie in particular between 380 nm and 780 nm. Advantageously, an operator of the laser rangefinder can detect the laser radiation emitted by the laser range finder without the aid of optical aids and in particular their projection onto a distant object as projected Perceive laser marking. In an alternative embodiment, the laser radiation may also lie in a spectral wavelength range which is invisible to the human eye, ie in particular below 380 nm or above 780 nm. In this case, the laser radiation emitted by the laser rangefinder is recognizable to the operator of the laser rangefinder only with the aid of optical aids (for example an infrared camera with laser radiation in the wavelength range of infrared).

The transmitting device is intended to emit laser radiation in different directions, in particular different relative directions with respect to the laser distance measuring device and / or a reference direction. The transmitting device is preferably provided to emit laser radiation in such a way that a laser beam representing the laser radiation periodically sweeps over an angular range α. For setting and changing the emission direction of the laser radiation, the transmitting device has a projection device. The projection device is provided for deflecting and / or diverting the laser radiation - in the following synonymously: the laser beam - in different directions, in particular different relative directions, relative to the laser range finder, for example relative to a housing of the laser range finder. For this purpose, the projection device has at least one laser beam steering means. A laser beam steering means is a device that appears appropriate to a person skilled in the art, but preferably a spatial light modulator (SLM), a refractive optical system, a mechanism for pivoting a laser and / or an optical system of the transmitting device, a micromirror array with a plurality of micromirrors, but particularly preferably a single optical system Micromirror, to understand.

In one embodiment of the laser range finding device, the projection device of the transmitting device has at least one at least one dimensionally deflectable mirror mounted, under the use of which laser radiation can be emitted under periodically variable relative directions in the angular range α or is emitted.

The at least one mirror can be realized as a micromirror. In particular, a micro mirror has a mirror surface is greater than 0.5 mm ^2, advantageously greater than 1 mm ^2, particularly advantageously greater than 2 mm ² on. Preferably, the mirror surface is pivotable by means of an electrical signal, in particular via at least one electrostatic actuator, at least in one direction. Alternatively or additionally, the mirror surface can be pivotable in two directions, in particular in two orthogonal directions, by means of an electrical signal, in particular via at least one electrostatic actuator.

The laser beam steering means continuously pivots the emitted laser beam over a particularly constant, preferably predefinable, angular range α. The projection device and / or a control device of the laser rangefinder is designed to adjust an angle of the emitted laser radiation, i. in particular an angle between relative directions of the emitted laser radiation, to detect, to control and / or preferably to regulate. In one embodiment, the projection device allows the laser beam to emit the angular range α periodically by swiveling the laser beam back and forth between two relative directions which define and limit the angular range α, in particular continuously. A "relative direction" is to be understood as meaning a direction relative to the laser range finder, for example relative to a housing of the laser range finder, or relative to a reference direction. Consequently, the laser beam periodically sweeps over the angular range α, i. he is deflected periodically. The periodic sweep of the angle range α is carried out in particular with a frequency greater than 20 Hz, preferably greater than 40 Hz, more preferably greater than 60 Hz. At a high periodic repetition rate of the deflection of the laser beam, the laser point projected onto the target object by means of a laser beam is transferred so rapidly the target object moves that a viewer, in particular the operator of the laser rangefinder, on the remote object perceives a projected, in particular solid, preferably continuously lit projection line or laser line, which corresponds in particular to the distance to be measured.

In addition to the light source and the projection device, the transmitting device can also have other optical elements, in particular beam-shaping and / or beam-directing and / or influencing the properties of the laser radiation, for example lenses, filters, diffractive elements, mirrors, reflectors, optically transparent panes or the like. In particular, optical elements may be provided which favorably focus and / or collimate the laser beam.

A laser beam reflected and / or scattered by the target object illuminated by the emitted laser beam, ie returning laser beam, is at least partially detected by the laser range finder and used to determine a distance to be measured. The returning laser beam is thereby by means of a detector device for detecting received light, in particular received returning laser radiation, at least partially detected. In this case, the detector device should be understood to mean at least one detector element which supplies a detection signal as a function of an incident light intensity. The term "detector element" is understood to mean radiation-sensitive, in particular photosensitive, elements such as photodiodes, for example PIN diodes or avalanche photo diodes (APD), but also (modulated) CCD chips and CMOS pixels. In one embodiment, the at least one detector element is formed by a single-photon avalanche diode (SPAD), in a further embodiment by a plurality of uncoupled or coupled SPADs, in particular from a SPAD array.

Using a control device and / or an evaluation device of the laser rangefinder, a light transit time can be determined from a phase comparison carried out between the emitted laser radiation and the laser radiation returning from the surface of the target object, and the sought distance between the laser range finder and the target object in the direction of the emitted laser beam via the speed of light be determined. A typical measuring range of the laser rangefinder is in a distance range of a few centimeters to several hundred meters. The determined distance measurement value in the direction of the emitted laser beam is then further processed by the control device and / or an evaluation device of the laser rangefinder and / or output by an output device of the laser rangefinder, for example using a display or an acoustic output device to an operator of the laser rangefinder. Alternatively or additionally, the distance measurement value can also be transmitted to a further device, for example a vehicle control system, an external data processing device or the like, for further processing.

The laser beam returning from the target object, in particular by reflection and / or scattering, is received using a receiving optical system. The receiving optical system is intended to receive light and in particular laser radiation from an angular range γ and to project it onto the detector device, in particular the detector element, preferably to image it. Preferably, the receiving optical system is provided to receive light and in particular laser radiation from a plurality of different angular sub-ranges σ and to project it onto the detector device. According to the invention, the receiving optics has laser radiation from an angular range γ on the detector device projecting facet optics.

By means of the receiving optics according to the invention in the form of the facet optics, light and in particular laser radiation can be projected onto the detector device from a preferably wide angular range γ. In particular, laser radiation which is emitted by the laser distance measuring device at a large transmission angle by means of the projection device can be projected onto the detector device by the facet optics, so that a distance determination is also possible in directions under great deflection of the emitted laser radiation.

Furthermore, the laser range finding device, in particular its control device and / or its projection device and / or its evaluation device and / or its detector device, is provided for distances to at least two, preferably to a plurality of different measuring points, i. in different directions of emission of the laser beam to determine promptly. Particularly preferably, the laser range finding device is provided to determine a certain number of distances with different relative directions, in particular in a timely manner, on a plane (also referred to below as the projection plane) in the angular range α. Preferably, the laser range finding device, in particular its projection device and / or its control device, detects an orientation of the relative directions, in particular relative to one another and / or advantageously relative to the laser rangefinder or relative to a component of the laser rangefinder. By "timely" is to be understood in an embodiment in particular that the laser rangefinder, in particular its control device and / or its projection device and / or its evaluation and / or its detector device, is provided to at least two distances within 500 ms, advantageously within 100 ms, particularly advantageous within 50 ms to determine.

In one embodiment, the number of distances with different relative directions into which the laser range finder determines distances may be predetermined or selectable by a user. In an alternative or additional embodiment, this number can also be specified inside the device, for example by the control device and / or the evaluation device. Thus, the number of distance measurements in different relative directions depending on the angular range α or the length of the indirectly to be measured distance on the target object can be estimated and / or calculated and specified.

Due to the inventive design of the laser rangefinder is particularly convenient design a comfortable, indirect measurement of a distance between two achievable only with the laser beam points on the target object possible without the laser rangefinder must be created at one of the points. Preferably, the distance to be determined indirectly is determined using trigonometric functions from a plurality of distance measurements in different relative directions between the laser distance measuring device and the target object and the angles enclosed between the relative directions. Such a route can be measured particularly advantageously at the push of a button within a short period of time, in particular less than one second. The operator may advantageously be at a distance from the track to measure the distance. At the same time a marking of the route to be measured in the form of the projected laser line is possible.

In addition to determining the length of a distance spaced from the laser range finder, the laser range finder is further provided to determine and output a direct distance between the laser range finder and the target object with the laser beam.

A "facet optics" is to be understood in particular as a receiving optics which divides the angular range γ - the so-called visual field of the receiving optics - into angular subareas σ - and thus into partial fields of view. In this case, each angular section σ is projected onto the detector device, in particular its detector element, preferably imaged. Preferably, the angle subareas σ are each projected onto the detector device with one facet of the facet optic, preferably imaged. Advantageously, in this way by means of the faceted optics as receiving optics from a remote object returning, i. In particular, reflected and / or scattered laser radiation from a preferably large angular range γ onto the detector device, in particular the detector element, can be projected, preferably imaged.

Advantageously, faceted optics can be used to replace classic, high-intensity and correspondingly expensive wide-angle optics. Such Weitwinkeloptiken must - starting from the requirement that the detector element for cost and design reasons should be as small as possible (for example, 10 mm in length) - have a small focal length of, for example f = 10 mm. Moreover, the requirement to project as much radiant power from each laser spot on the target object onto the detector device requires a small f-number f / #, which in the example given is approximately f / # = 0.9. The facet optics make it possible to circumvent these disadvantages of classical, high-intensity wide-angle optics, which are particularly complex and expensive both in terms of production and adjustment due to their f-number close to 1. In particular, using the facet optics, the number of lenses and strongly curved surfaces in the receiving optics of the laser range finder can be greatly reduced. By dividing the angular range γ into angular sub-ranges σ, which can be projected in particular simultaneously on the detector device, in particular its detector element, by means of the facet optics, the design-related requirements for the receiving optics can be significantly mitigated for a given angular range γ and predetermined detector size. In the case of the facet optics, each of the angle subareas σ is preferably projected onto the detector device by one of the facets corresponding to the number of angular subareas σ, preferably imaged. A particularly short focal length - as would be necessary with wide-angle optics - can thus be counteracted while simultaneously relaxing the critical f-number f / #.

Since the laser range finder operates to scan over the angular range α, i. the laser radiation by means of the projection device of the transmitting device, the angular range α is emitted periodically sweeping, only one laser point of the field of view of the receiving optics, i. in the angular range γ, illuminated. As a result, an unambiguous association between the pixel on the detector device and the laser spot on the target object-for example, determined by a deflection angle of the projection device-can advantageously be made possible.

In particular, the facet optics permit returning laser radiation from the entire angular range γ to be received in a timely manner over the angular range α in a scanning manner on the target object.

In one embodiment of the laser range finding device, the facet optics consists of a plurality of n facets in the form of focusing optical lenses, the n facets dividing the angular range γ into the number n of angular facets corresponding to the facets, and each of the n facets dividing the associated angular portion σ onto the detector device projected.

Thus, the entire field of view of the receiving optics, ie the angular range γ, is divided into n angular sub-ranges σ, each angular sub-range σ being preferably projected onto the detector device, in particular its detector element. The projection or the image of the corresponding angular subareas σ takes place via focusing optical lenses, so that returning laser radiation is preferred at long distances focused on the at least one detector element of the detector device is imaged.

By dividing the field of view or the angle range γ into n partial fields of view or angular sections σ, the focal length of the receiving optics can be increased by the factor n while the critical f-number f / # is relaxed by the factor n.

In one embodiment of the laser range finder, the facet optic consists of a plurality of spherical or aspherical optical lenses.

Spherical lenses, by design, are particularly simple lenses in which optically active surfaces are spherical, i. are shaped as surface cutouts of a sphere. Advantageously, the use of spherical lenses can help reduce manufacturing costs. Furthermore, in particular focusing converging lenses can be produced as spherical lenses with two convex surfaces or with a convex and a flat surface economically particularly simple and thus cost.

Similar to spherical lenses, aspherical lenses are rotationally symmetric, but not circular in section. For this reason, aspherical lenses can have advantageous imaging properties compared to spherical lenses, since in particular principle-related aberrations such as aberration, astigmatism or the like occur only greatly reduced.

In an alternative embodiment, the facet optics may also consist of a plurality of gradient lenses, in which the refractive index changes spatially.

In particular, the facets of the facet optics can each be embodied identically or alternatively be designed differently in each case to improve the projection properties of the facet optics.

In one embodiment of the laser range finder, the facet optics between adjacent facets have first means that counteract optical crosstalk of light between the facets.

Such first means may, for example, be filters provided between the optical lenses of the facet optics, reflectors, absorbers or the like. The first means make it possible to reduce, in particular completely avoid, optical crosstalk of light between neighboring facets.

In this context, an "absorber" should be understood to mean, in particular, an element which is at least partially provided for receiving and / or transforming energy. This is preferably understood to mean, in particular, an element which is provided for absorption of radiation, preferably of electromagnetic radiation and particularly preferably of visible light. Preferably, this is to be understood as meaning, in particular, an element having an absorptivity of at least 0.6, preferably of at least 0.8 and particularly preferably of at least 0.9 in the case of visible light.

In one embodiment, the first means, in particular the filters, the reflectors and / or the absorbers, are each formed in the form of a separating layer. The separating layer preferably extends completely between each adjacent facets of the facet optical system.

In this way, an optical separation between the lenses of individual facets of the facet optics can take place. In this way, overlaps and / or superimpositions of received signals, in particular overlaps and / or superimpositions of laser radiation and background light, can be avoided by means of different facets of different angular sub-ranges σ projected.

In one embodiment of the laser range finding device, the receiving optical system has second means which allow angular subareas Ω, in particular the angular subareas σ, to be sequentially projected onto the detector device via the n facets.

In this case, the second means may be designed as a mechanical shutter or shutter which forms an at least partially light-tight, mechanically movable element and is in the receiving path of the laser rangefinder in front of the detector device, in particular in front of the detector element.

The second means may in principle be provided at different locations in the reception path, for example in the direction of the reception path, either in front of or behind the reception optics, in particular in front of or behind the facet optics. In one embodiment, the second means, in particular the shutter, seen in the direction of the reception path immediately behind the receiving optics, i. between receiving optics and detector element provided.

In an exemplary embodiment, the second means in the form of a slit closure, in particular a slat-type slit closure, a spherical shell closure, a Roller shutter, a shutter shutter, a guillotine closure or in the form of another, a professional appear appropriate closure and / or light modulator designed to cover at least substantially light-tight selectable areas of the receiving optics. By means of light-tight coverage of selectable regions of the receiving optics, it is possible to generate defined, selectable and light-transmissive regions of the receiving optics. The light-permeable areas of the receiving optics are "activatable" in this way. These defined, selectable and light-transmissive regions of the receiving optics also allow selectable angular sub-ranges Ω, preferably the angular sub-ranges σ of individual facets, to be projected onto the detector device.

The closure may be adjustable, preferably electronically adjustable, such that, at least during an operating state of the laser range finding device, the regions of the receiving optics which are defined in terms of their angular extent and which are selectable and permeable to light - i.e. the angular sub-regions Ω, preferably the angular sub-regions σ of the receiving optics-changed with regard to their position, in particular can be displaced relative to the receiving optical system. The displacement can take place either in discrete steps or in a continuous movement. In this way, in one embodiment of the laser range finding device, a light-transmissive region, in particular the angular sub-region Ω, preferably the angular sub-region σ, can be moved or scanned above or relative to the receiving optical system. Furthermore, individual and / or several adjacent facets can be activated with angular sections σ, while all other angular sections are covered in a light-tight manner.

The angle subareas Ω at this point generally designate angle subareas of arbitrary extent with Ω <α, so that, for example, a single, several or even subareas of one or more facets - which in turn each define an angular subareas σ - can be covered in a light-tight manner. Preferably, the angle portions Ω exactly the angular portions of a facet σ represents, so that the shutter or shutter allows light entry through individual facets or more facets selectively enable ("activate"), while other facets are covered in a light-tight manner and thus light through these covered facets is blocked. In this way, as a result of a sequential covering of individual areas or individual facets, the adjustable shutter allows angular subareas Ω or in particular the angular subareas σ defined by the n facets to be sequentially projected onto the detector device by means of the n facets.

In one embodiment of the laser range finder, the second means are formed as an at least partially light-tight, mechanically movable element having a double curtain or a slit. The opening of the curtain or the slot can be moved substantially perpendicular to the receiving path through the receiving path, so that viewed from the detector element, an angular range Ω, in particular an angular range σ, remains free for the passage of light. The remaining, covered by the shutter part of the angular range γ of the receiving optics is advantageously covered light-tight. If the opening of the curtain or the slot is moved, the angular subareas Ω, in particular the angular subareas σ, can be sequentially projected onto the detector device by means of the n facets.

It is advantageously possible to achieve an improvement in the radiometric performance of the receiving optics by at least partial areas of the facetted optics being light-tightly concealed by reducing the transmission of the facets or facet areas or facet subareas that are not relevant for the imaging of an angular subarea Ω.

In an alternative or additional embodiment, the second means may also be realized as an LC display which is provided in or close to the aperture stop plane of the receiving optics.

In one embodiment of the laser range finding device, the relative direction under which laser radiation can be emitted by means of the projection device is coupled to the angle subarea Ω, in particular the angle subarea σ, from which incident electromagnetic radiation is projected onto the detector device.

By "ausendbar" is meant in particular that laser radiation by means of the projection device during the operation of the laser rangefinder, in particular during a distance measurement, actually emitted.

Advantageously, by coupling the direction under which laser radiation is emitted by means of the projection device with the angular sub-ranges Ω, preferably with the angular sub-range σ, from which incident electromagnetic radiation is projected onto the detector device, a transmission during a measurement of unused and / or unneeded Angle portions Ω, preferably unnecessary facets, the facet optics are reduced. In particular, by an actively controlled, preferably scanning second means such as a shutter, shutter, LC display or the like, which directly with the size of the entrance pupil, in particular with the number of Facets, linearly increasing detection of background radiation, in particular background light, to be counteracted.

The proportion of the background radiation, in particular the proportion of background light, which is projected onto the detector device together with returning laser radiation during a measuring operation, can thus be reduced significantly. Thus, the signal-to-noise ratio in the distance measurement can be significantly improved, in particular significantly increase. Furthermore, such a duration of a measurement performed can be reduced and a quality of the measurement can be increased.

In one embodiment of the laser range finding device, the receiving optical system has third means, in particular a spectral filter, which allow at least partially to filter electromagnetic radiation incident from the angular range γ.

In one embodiment, the third means are designed as a spectral filter which selects or filters incident electromagnetic radiation, in particular light, according to defined criteria. Advantageously, radiation incident in this way, which initially consists of backscattered or reflected laser radiation and other radiation contributions, in particular background light or the like, can be at least partially reduced to the laser radiation of interest. For example, filters for selective filtering by wavelength, polarization state or the direction of incidence of the electromagnetic radiation can preferably be used.

Spectral bandpass filters or color filters, for example, are suitable for filtering the wavelength of the electromagnetic radiation incident through the receiving optics and thus for allowing only the desired laser radiation to pass unhindered onto the detector device, in particular the detector element.

In one embodiment, the third means are applied directly on at least one surface of the receiving optics, in particular on at least one surface of each of the facets.

In one embodiment of the laser range finding device, a maximum angle range α _max , in which the laser radiation is transmitted by means of the projection device of the transmitting device periodically sweeping the angular range α, at least 30 degrees, preferably at least 60 degrees, more preferably at least 90 degrees.

The projection device is adapted accordingly to deflect the laser beam in a maximum angular range α _max of at least 30 degrees, preferably of at least 60 degrees, more preferably of at least 90 degrees. The deflection of the laser beam can take place within this angular range, at least in discrete steps of, in particular, less than 1 degree, preferably less than 0.1 degrees. Particularly preferably, the deflection of the laser beam in the corresponding angular range takes place continuously or quasi-continuously, ie in particular with steps of less than 0.01 degrees.

It should be noted at this point that the maximum angular range α _{max predetermines} the technically possible angular range for deflecting the laser radiation, ie the angular range in which the laser radiation can be emitted periodically by sweeping the angular range α. The maximum angle range α _max is therefore not to be confused with the basically arbitrary angular range α, in which the actual, periodic deflection (scanning) of the laser beam takes place. In particular, the laser beam can thus be emitted periodically sweeping over any angle ranges α (α ≦ α _max ) within the maximum angular range α _max , for example an angular range of 5 degrees, 13 degrees, 26 degrees or the like up to α _max .

Thus, in this way, the emitted laser beam can be deflected over a large angular range α, in particular scanned.

In one embodiment of the laser range finding device, the angular range γ is greater than or equal to the maximum angular range α _max . In this way, the entire angular range α periodically swept by the laser radiation by means of the projection device can be projected onto the detector device with α ≦ α _max by means of the receiving device, in particular by means of the facet optical system. The angular range γ of the receiving optics preferably overlaps with the entire angular range α _{max of} the projection device, so that returning laser radiation of each laser beam emitted in any direction of the angular range α within the maximum angular range α _max is detected by the receiving optics and for detection on the detector device, in particular the detector element is projectable.

In an exemplary embodiment of the laser range finding device, the facet optics consists of five facets in the form of focusing optical lenses, in particular in the form of laser lenses focusing optical lenses, the five facets an angular range γ of at least 60 ° in five angular portions σ divided into 12 ° and each of five facets projected and / or imaged the associated angle portion σ of 12 ° on the detector device.

An angular range γ of at least 60 ° represents an application-oriented angular range which is preferred for the realization of the laser rangefinder. The subdivision of the angular range γ of at least 60 ° into five angular sub-ranges σ of 12 ° each further represents a preferred embodiment of the laser rangefinder in which the the receiving optics asked technical requirements - large entrance pupil per facet, focal length of the facet optics and the like - and with regard to their production to consider economic boundary conditions - number of strongly curved surfaces, design of the individual facet lenses and the like - are weighed against each other.

It should be noted, however, that the facet optics can alternatively also be embodied from a different number of facets with different angular subareas σ and a different angular range γ.

In one embodiment of the laser range finding device, the facet optics are realized in one piece, in particular realized as a one-piece injection-molded component or an injection-molded component.

By "in one piece" is to be understood in particular that the faceted optics is made as a single, preferably cohesive component, so that it preferably does not consist of several individual facets joined together and the individual facets of the facet optics can not be detached from one another without being destroyed ,

In one embodiment, the facet optic is manufactured as an injection molding component in an injection molding process. As an injection-molded component, the faceted optics is produced using an injection mold, in particular an injection mold, into which a suitable material is injected and then cured. In particular, transparent glasses or plastic materials such as, for example, polycarbonates, polymethyl methacrylates or cyclo-olefin (co) polymers are suitable for producing the faceted optics by means of an injection molding process. In this way, the faceted optics can be manufactured in a particularly simple and cost-effective manner. Advantageously, a subsequent grinding of the facet optics to comply with quality requirements can be largely avoided.

In one embodiment of the laser range finding device, the detector device has at least one SPAD, preferably a SPAD array.

A single-photon avalanche diode, SPAD for short, can, insofar as it is operated in the so-called Geiger mode, have the property that it does not deliver a detection signal linearly dependent on the incident radiation, as with conventional analog light-sensitive elements, but with a single signal is generated for each incident photon. The SPAD has a paralyzable response, so that it can not be reactivated after a photon has hit it for a certain dead time, which can range from, for example, 1 to 100 ns. The count rate with which a SPAD can count incident photons is thus limited by the dead time. The detector device, in particular the detector element, therefore advantageously has a multiplicity of smaller SPADs in the form of a SPAD array instead of a single large-area SPAD. Preferably, in each case a plurality of SPADs of the SPAD array can be combined to form a pixel of the detector element, wherein detection signals of SPADs contained in a single pixel are combined by means of a combiner, in particular an OR gate or in the form of a bus. In this way, the maximum achievable by a pixel photon counting rate can be increased or the dead time of the pixel between individual detection events are shortened. Further, a pulse shortener may be disposed between a SPAD and a combiner or bus to temporally shorten a digital signal generated by the SPAD, thereby enabling a shortened overall dead time and an increased photon counting rate of the system.

Due to the digital output of the detector circuit, in particular comprising combiners, OR gates or the like, advantageously a particularly fast and simple provision of the detection signal can be realized. Compared to analog photosensitive elements, such as avalanche photodiodes (APDs), a detection and signal delivery speed can be increased.

Since each facet of the receiving optics images the laser point projected onto the target object over an angular segment σ onto the detector element, the point of light of the returning laser beam projected onto the detector element migrates over the detector element as a function of the direction in which the laser radiation is emitted. The use of a SPAD array advantageously makes it possible to ensure that laser radiation received by means of the facets is always projected onto the detector device, in particular onto the detector element. In particular, the SPAD array may have an elongated (elongated) extent with a multiplicity of SPADs in at least one direction. In this case, the SPAD array is preferably oriented in such a way that this elongated extent of the SPAD array lies in the projection plane.

It should be noted that an optical position corresponding to the number of facets ambiguous position of the imaged light spot on the detector element can be assigned to each optical transmission angle of the laser radiation. Preferably, the ambiguity can be resolved by an unambiguous association between the image on the detector device and the laser spot on the target object, ie between the light spot on the detector device and the optical transmission angle of the emitted laser radiation.

In one embodiment of the laser range finder, the facet optic focusing optical lenses project laser radiation onto the SPAD array of the detector device such that at least 2 × 2 SPADs of the SPAD array are illuminated. In particular, at least 2 × 2 SPADs of the SPAD array are illuminated under optimal imaging conditions.

Thus, it is ensured by design that a projected or imaged light spot of the returning laser beam is at least not smaller than a SPAD of the SPAD array. In this way, it can be ruled out that detection gaps or blind spots in the detectable field of view or angle range γ that would occur when the laser spot falls between adjacent active areas, in particular photosensitive areas, of the SPADs, are eliminated. In particular, illumination of a plurality of SPADs, particularly at least 2 × 2 SPADs of the SPAD array, is important if the SPADs of the SPAD array used have a low fill factor, i. a low ratio of light-sensitive to light-insensitive surfaces, have.

The requirement for illumination of at least 2 × 2 SPADs of the SPAD array can be achieved in one embodiment by adjusting the focusing optical lenses of the facet optics or by the optical design of the facet optics.

Finally, it should be mentioned that the preceding remarks in an analogous manner obvious to the person skilled in the art can also be applied to a two-dimensional application of the laser range finding device according to the invention. In such an embodiment, the laser beam is transmitted by means of an alternatively configured projection device of the transmitting device a solid angle range A periodically sweeping. The receiving optical system furthermore has a two-dimensionally configured facet optical system, by means of which laser light returning from the solid angle range γ is projected onto the detector device for detection, preferably being imaged. The individual facets divide the solid angle range Г into solid angle partial ranges Σ.

• • Laserstrahlung mittels einer Projektionsvorrichtung der Sendevorrichtung einen Winkelbereich α periodisch überstreichend auf ein entferntes Objekt hin ausgesendet wird,
• • von dem entfernten Objekt rücklaufende Laserstrahlung mittels einer Facettenoptik auf zumindest eine Detektorvorrichtung projiziert wird,
• • wobei Entfernungen in verschiedene Relativrichtungen zwischen dem Laserentfernungsmessgerät und dem entfernten Objekt sowie Winkel zwischen den Relativrichtungen ermittelt werden und unter Verwendung trigonometrischer Funktionen aus zumindest zwei in unterschiedliche Relativrichtungen ermittelten Entfernungen sowie dem zwischen diesen zumindest zwei Relativrichtungen eingeschlossenen Winkel die Distanz auf der Oberfläche des entfernten Objekts berechnet wird.

Furthermore, an inventive method for determining a distance on a surface of a remote object by means of the laser range finding device according to the invention is proposed, in which

• Laser radiation is transmitted by means of a projection device of the transmitting device an angle range α periodically sweeping towards a distant object,
• • laser radiation returning from the remote object is projected onto at least one detector device by means of facet optics,
• Wherein distances in different relative directions between the laser range finder and the remote object and angles between the relative directions are determined and using trigonometric functions from at least two distances determined in different relative directions and the included between these at least two relative directions the distance on the surface of the remote object is calculated.

In one embodiment, the laser radiation may be in a spectral wavelength range visible to the human eye, i. in particular between 380 nm to 780 nm. Advantageously, an operator of the laser distance measuring device can recognize the laser radiation emitted by the laser distance measuring device without the aid of optical aids and, in particular, perceive its projection onto a distant object as projected laser marking. In an alternative embodiment, the laser radiation may also be present in a spectral wavelength range invisible to the human eye, i. especially below 380 nm or above 780 nm. In this case, the laser radiation emitted by the laser rangefinder is recognizable to the operator of the laser rangefinder only with the aid of optical aids (for example an infrared camera with laser radiation in the wavelength range of infrared).

In one embodiment of the method for determining a distance, the laser radiation is emitted periodically sweeping the angle range α such that a projected laser line is displayed on the remote object.

Preferably, the laser radiation is transmitted by means of a laser beam steering means continuously over a particular constant, preferably predeterminable, angular range α. The periodic sweep of the angular range α is carried out in particular with a frequency greater than 20 Hz, preferably greater than 40 Hz, more preferably greater than 60 Hz. At a high periodic repetition rate of the deflection of the laser beam of the means Laser beam projected onto the target object laser point so quickly moved over the target object that a viewer, in particular the operator of the laser rangefinder on the remote object a projected, especially solid, preferably continuously lit projection line or laser line perceives that corresponds in particular to the track to be measured.

In one embodiment of the method for determining a distance, a length of a distance on the remote object which is swept periodically by the laser radiation, in particular the length of the projected laser line, is determined. In particular, the length of the route is calculated using trigonometric functions from at least two distances determined in different relative directions as well as the angle enclosed between these at least two relative directions.

In one embodiment of the method for determining a distance, the projection device is controlled and / or regulated in an operating state of the laser rangefinder such that the distance on the remote object, which is swept periodically by the laser radiation, in particular the projected laser line, assumes a predeterminable length.

In this way, an operator of the laser rangefinder can be particularly comfortable represent distances on a remote object and check in particular with regard to a length. For example, the operator can quickly check if a cabinet of a given width fits into an existing niche. An "operating state" is to be understood here as an operator-influenceable state, at least of the control device of the laser range finding device, in which the control device executes operator-selectable control routines, control routines and / or calculation routines.

The control device regulates the length of the projected line by first determining the distance of the end points between which the emitted laser beam is reciprocated and comparing it with the length value predetermined by the operator in particular. Subsequently, the control device alters the angle between the two relative directions which define the length of the projected line, such that the end points are spaced apart from each other by the predetermined distance.

For user-friendly input of a length value and / or an angle between the two relative directions which define and limit the angle range α, the laser rangefinder can have an input unit by means of which an angle and / or a length value can be set and / or entered.

drawings

The invention is explained in more detail in the following description with reference to exemplary embodiments illustrated in the drawings. The drawings, the description and the claims contain numerous features in combination. The person skilled in the art will expediently also consider the features individually and combine them into meaningful further combinations. Like reference numerals in the figures indicate like elements.

1 Perspective view of an embodiment of the laser rangefinder according to the invention in the form of a hand-held 1D-line laser rangefinder

2 Schematic sectional view of the hand-held 1D line laser rangefinder 1

3 Schematic view of the handheld 1D line laser rangefinder 1 that is in an exemplary environment to be measured

4 Schematic representation of beam paths in an embodiment of the laser range finding device (a) according to the invention in side elevation and (b) in front elevation

5 Representation of coordinates (a) of the projected light spot on the detector element and (b) of the laser spot on the surface of the target object plotted against the emission angle of the emitted laser beam

6a , b Schematic representation of beam paths in an embodiment of the laser rangefinder according to the invention with a shutter in side-view

7 Perspective view of an alternative embodiment of the laser rangefinder according to the invention in the form of a hand-held laser rangefinder

8th Embodiment of a method according to the invention for determining a distance on a surface of a remote object.

Description of the embodiments

1 shows a perspective view of an embodiment of a laser rangefinder 10 in the form of a hand-held 1D Line laser distance measuring device 10 ' as it is, for example, in activities in the craft sector, for example, in the measurement of objects or interiors, can be used. Such an application in the context of an exemplary measurement constellation is in a schematic plan in FIG 3 shown in the hand-held laser rangefinder 10 is used in an environment to be measured. The essential components of the laser rangefinder for operation 10 are in a sectional view of the laser rangefinder 10 in 2 shown schematically.

The principles of the hand-held 1D line laser range finder described below with reference to the figures 10 ' are in the context of other embodiments also to other embodiments of a laser rangefinder according to the invention 10 transferable, which can perform similar or other tasks. In particular, the principles are also applicable to stationary and integrable laser rangefinders 10 transferable, for example to laser distance measuring devices integrated in motor vehicles 10 which are used to measure distances during a navigation of the motor vehicle and / or in connection with a safety device of the motor vehicle.

The laser rangefinder 10 points as in 1 represented a housing 12 , a display 14 as well as actuators 16 . 16 ' to turn the laser rangefinder on and off 10 and to start or configure a measurement process. Furthermore, the laser rangefinder has 10 to the energy supply to a power supply device, not shown, in particular a battery or a rechargeable battery, preferably a lithium-ion battery, on. The housing 12 takes the for the operation of the laser rangefinder 10 relevant and / or useful components of the laser rangefinder 10 on. Preferably encloses the housing 12 These components and thus protects them against the ingress of contaminants, moisture and mechanical action as a result of shocks or the like.

The laser rangefinder 10 is using a control device 18 for controlling the functional components of the laser rangefinder 10 operated. The control device 18 is connected to these components by signal technology. Under the control device 18 should be understood in particular a device with at least one control electronics, the means for communication with the other components of the laser rangefinder 10 For example, means for controlling and / or regulating a projection device 20 and / or means for data processing and / or further, to those skilled appears reasonable means. The control device 18 Provides operational function parameters of the laser rangefinder 10 as a function of at least one operator input and / or an evaluation result of a measurement. Under the control electronics of the control device 18 For example, a processor unit is to be understood in connection with a memory unit and with an operating program stored in the memory unit, which is executed during the control process. In particular, the electronic components of the control device 18 arranged on a circuit board (printed circuit board) and preferably in the form of a microcontroller. The control device 18 allowed, the laser rangefinder 10 to control and to enable its operation. The control device 18 communicates with the other functional components of the laser rangefinder 10 , in particular at least one projection device 20 , a detector device 22 , a data interface 24 , especially the display 14 and the actuators 16 . 16 ' , as well as a shutter control 26 ' and other components which appear appropriate to the person skilled in the art.

The hand-held laser rangefinder 10 is intended to be guided by an operator only with the hands, preferably with one hand. For this purpose, the total mass is less than 500 g and the dimension of the longest side is less than 15 cm.

The laser rangefinder 10 has an in 2 transmitting device shown in detail 28 for generating and emitting time-modulated laser radiation 30 on. The sending device 28 includes a laser diode 32 for generating time-modulated, in particular continuously and / or periodically modulated, laser radiation 30 in the visible spectral range (for example 630 nm). To measure the distance of the laser rangefinder 10 to a target object 34 (see in particular 3 ) is in operation of the laser rangefinder 10 essentially collimated laser radiation 30 via a transmission optics 36 the transmitting device 28 in the direction of the target object 34 Posted. The transmission optics 36 exists in the in 2 illustrated embodiment of the hand-held laser rangefinder 10 from lenses 36b . 36c , a beam collimator 36d as well as one in the housing 12 of the laser rangefinder 10 integrated exit window 36a , In an alternative embodiment, the transmission optics 36 also other beam-shaping and / or beam-directing and / or the properties of the laser radiation 30 influencing optical elements, for example lenses, filters, diffractive elements, mirrors, reflectors, optically transparent discs or the like.

The sending device 28 of the laser rangefinder 10 has a projection device 20 on, by means of laser radiation 30 using a laser beam steering means 38 in different directions - synonymous in the following: in different relative directions 84a . 84b . 84c - with different outside angles 40 relative to the laser rangefinder 10 or a reference direction 42 , from the laser rangefinder 10 can be emitted (see in particular also 3 ). The laser beam steering means 38 is in the in the 2 illustrated embodiment as a micromirror 38 ' realized. The micromirror 38 ' has a mirror surface of about 1 mm ² and is deflectably mounted in one-dimensional direction, as in the 2 . 4a . 6a and 6b each by a small bidirectional arrow next to the micromirror 38 ' is indicated.

The micromirror 38 ' is with an actor 44 connected, here an electrostatic actuator, using a control unit 20 ' the projection device 20 is controlled, so the micromirror 38 ' defined in one-dimensional direction and in particular can be continuously pivoted or deflected over an angular range of at least 30 °. In particular, panning is to be understood as panning with steps of less than 0.005 degrees. Such can be done by means of the control unit 20 ' the projection device 20 the transmission angle 40 under which the laser radiation 30 out of the case 12 of the laser rangefinder 10 is emitted, in particular one-dimensional direction predetermined and adjusted, in particular controlled and / or regulated. Because the micromirror 38 ' is pivotable in one-dimensional direction, which spans in different relative directions 84a . 84b . 84c emitted laser radiation 30 a projection plane ("laser fan") on.

The control unit 20 ' the projection device 20 allows the angle under which the laser radiation 30 relative to the laser rangefinder 10 or a reference direction 42 is emitted. For this purpose, the control unit 20 ' an information input, an information processing, an information output, a processor and in a memory of the control unit 20 ' stored operating programs and / or control routines and / or control routines and / or calculation routines. In particular, the term "adjust" should be understood to mean that the control unit 20 ' at least outputs a parameter that is intended to the actuator 44 the laser beam steering means 38 for adjusting the relative direction 84a . 84b . 84c to control and / or to regulate.

By means of in 2 . 4 . 6a and 6b shown projection device 20 becomes in at least one operating mode of the laser range finder 10 as a result of suitable activation of the actuator 44 through the control unit 20 ' the micromirror 38 ' so continuously, in particular periodically pivoted that the laser radiation 30 between two relative directions 84a . 84b . 84c which has an angular range α (cf. 4a , Reference number 46 ), and is continuously swung back and forth. Like in the 3 can be represented by continuous, periodic pivoting of the micromirror 38 ' in a deflection range of the mirror of up to ± 15 degrees, the emitted laser radiation 30 - Also continuously - over an angular range α (reference numeral 46 ) are pivoted by up to 60 degrees, in particular be pivoted periodically. The emitted laser radiation 30 lies in the so-called projection level. In particular, the projection plane is defined by those two laser beams (in relative directions 84a . 84b in 3 ) of the laser radiation 30 defined under positive and negative full excursion of the micromirror 38 ' be emitted.

Will the laser radiation 30 , as in 3 shown on a target object 34 projected, migrates as a result of the continuous pivoting of the micromirror 38 ' one by means of the laser radiation 30 on the target object 34 projected laser spot 48 continuously over the surface of the target object 34 , This is in the 3 with a bidirectional arrow 50 represents the periodic swinging of the laser spot 48 symbolizes. Thus, the emitted laser radiation passes over 30 the angular range α ( 46 ) periodically, in particular in a periodic and / or cyclical reciprocation. The periodic sweep of the angular range α ( 46 ) takes place with a frequency greater than 20 Hz. In doing so, the laser radiation 30 on the target object 34 projected laser spot 48 so swiftly over the target object 34 that moves a viewer on the target object 34 a projected, solid and continuously lit projection line or laser line 52 perceives. In other words, the laser radiation 30 in at least one mode of operation of the laser range finder 10 time-scanned for a target object 34 emitted so that on the target object 34 a one-dimensional laser line 52 projected and thus for an operator of the laser rangefinder 10 becomes visible.

Further, the control unit 20 ' the projection device 20 provided, the laser beam steering means 38 , in particular the actuator 44 in an operating mode of the laser range finder 10 to regulate such that the projected laser line 52 takes a given length. In this way, an operator of the laser rangefinder 10 particularly comfortable routes on the target 34 show and check. For example, the operator can quickly check if a cabinet of a given width fits into an existing niche. In particular, a clamping angle and / or a length of the laser line 52 by means of the actuators 16 in particular by means of an input unit provided for inputting angles 16 ' , specifiable by the operator.

Under an operating mode, an operating state that can be influenced by an operator is intended to be at least one operating state of the control device 18 to be understood, in which the control device 18 executes operator-selectable control routines, control routines and / or calculation routines. The control device 18 is intended to perform various modes of operation.

In this context, rules should in particular be understood to mean that the control device 18 a distance between the two endpoints 54a . 54b the laser line 52 determined to each other, which compares the determined distance with the distance given by the operator (in 3 : 2.00 m) and then the angle between the endpoints 54a . 54b the laser line 52 defining relative directions 84a . 84b changed so much that the endpoints 54a . 54b are spaced apart at the predetermined distance. A determination of the distance of the two endpoints 54a . 54b the laser line 52 , and thus the length of the laser line 52 , is preferably indirectly using trigonometric functions from multiple range measurements in different relative directions 84a . 84b . 84c between the laser rangefinder 10 and the target object 34 as well as between the relative directions 84a . 84b . 84c enclosed angles determined (see in particular 3 ).

The from a surface of the target object 34 reflected and / or backscattered laser radiation 30 ' (not shown here in detail; 5c ) is via a receiving optics 56 of the laser rangefinder 10 on a detector element 22 ' a detector device 22 imaged and detected there. The detector device 22 including detector element 22 ' is in 2 shown. The detector device 22 includes in this embodiment - and in particular in the in the 4 . 6a . 6b illustrated embodiments - a SPAD array 58 as a detector element 22 ' (see in particular 5c ). The SPAD array 58 has an elongated shape in the direction of the projection plane. For example, the dimensions of the SPAD array are 58 in the projection plane 10 mm and perpendicular to this 1 mm. The SPAD array 58 delivers depending on an incident light intensity, in particular laser radiation intensity, a spatially resolved detection signal. This is the SPAD array 58 from a multiplicity of uncoupled or coupled, in particular couplable, SPADs 58 ' , In one embodiment, the SPAD array 58 500x50 photosensitive SPADs 58 ' on. The detector device 22 is signal technology with the control device 18 of the laser rangefinder 10 connected to the forwarding of detection signals.

From one between the emitted laser radiation 30 and that of the surface of the target object 34 returning, ie reflected and / or backscattered laser radiation 30 ' performed phase comparison can by means of the control device 18 of the laser rangefinder 10 , in particular an evaluation unit of the control device 18 , Determines a light transit time and the speed of light, the distance between the laser rangefinder 10 and the impact point on the target object 34 be determined. The specific distance corresponds to the distance of the laser rangefinder 10 from the target object 34 in the direction of the target object at that time 34 emitted laser radiation 30 , From the detection signals from the control device 18 determined distance measurement values in the direction of the emitted laser radiation 30 are subsequently from the control device 18 of the laser rangefinder 10 further processed and / or by means of a data interface 24 of the laser rangefinder 10 to an operator of the laser rangefinder 10 output. In particular, an output can be made using the display 14 respectively. Alternatively or additionally, the distance measurement value can also be used for further processing using the data interface 24 to another device, such as a mobile data processing device such as a smartphone, a tablet, a PC, a computer or the like, are transmitted.

As in the 1 - 3 already indicated and in the 4 . 6a and 6b shown in more detail, has the laser rangefinder 10 According to the invention, a receiving optics 56 on, the at least one laser radiation 30 ' from an angular range γ ( 60 ) for detection on the detector device 22 projecting faceted optics 62 includes. In this case, the angular range γ ( 60 ) of the receiving optics 56 the angular range α ( 46 ), in the laser radiation 30 by means of the projection device 20 is emitted or can be emitted. In other words, the angular range γ ( 60 ) includes the angular range α _max (not shown in detail), the maximum technically with laser radiation 30 paintable angle range α ( 46 ) from here 60 degrees. As related to 5a will be explained, the faceted optics 62 In an exemplary embodiment, an angular range γ ( 60 ) of 60 degrees, from the returning laser radiation 30 ' on the detector device 22 can be projected. The faceted look 62 consists of five facets 64a . 64b . 64c . 64d . 64e (hereinafter also: 64a -one Shape of focusing, in particular spherical or aspherical, optical lenses. Every facet 64a E forms an angular range σ (reference numeral 66a -E) of 12 ° on the detector device 22 from. The faceted look 62 is economically simple and inexpensive to manufacture as a one-piece injection-molded component in an injection molding process. As a material of faceted optics 62 For example, a transparent glass or plastic material, for example polymethyl methacrylate, is preferably used. The faceted look 62 represents a single component whose facets 64a -E can not be solved without the facet optics 62 to destroy.

It should be noted that the numerical values mentioned concerning facet optics 62 such as 60 degrees, 12 degrees, and the like in this embodiment are merely exemplary selected preferred values of this embodiment. Deviating values for the angular range γ (which appear reasonable to a person skilled in the art) 60 ) and the maximum swept angle range α _max are conceivable. It should also be noted that the transmitting and the receiving optics of the in the 1 - 3 illustrated embodiment of the laser rangefinder 10 lie next to each other in the projection plane, while in the 4 and 6 illustrated embodiment, the transmitting and receiving optics are arranged side by side perpendicular to the projection plane.

The faceted look 62 points between adjacent facets 64a -E each first means 68 in the form of an absorber 68 ' and / or filters 68 '' on, which is an optical crosstalk of light between the facets 64a -E counteract. The absorber 68 ' and / or filters 68 '' are each as one completely between each adjacent facets 64a -E the receiving optics 56 extending separating layer carried out (see, in particular 4a and 4b ). Furthermore, the faceted optics 62 on the surface not shown third means 70 in the form of a spectral color filter 70 ' on, which allow, from the angular range γ ( 60 ) to at least partially filter incident electromagnetic radiation with respect to its wavelength. Using the first and third means, spurious background radiation, which has a detrimental effect on the accuracy of measurement results, is advantageously reduced.

In 4a and 4b are the essential optical components of the laser rangefinder 10 - Projection device 20 with micromirror 38 ' , Detector element 22 ' and faceted optics 62 - Shown schematically in a side view (the considered xz plane corresponds to the projection plane) or a front view (xy plane). laser radiation 30 is first using lenses 36b . 36c and a collimator 36d formed into a focused laser beam or laser beam. This shaped laser radiation 30 is through the micromirror 38 ' deflected and at a given time at a defined angle relative to a reference direction 42 from the laser rangefinder 10 emitted. The from every facet 64a -E the faceted optics 62 on the detector element 22 ' Imaged angular sections σ ( 66a -E) are represented by dashed lines in the context of geometric optics, the respective angular sub-regions σ ( 66a -E). The sum of the angular sub-ranges σ ( 66a -E) biases the angular range γ ( 60 ) on.

As in 4b shown in the front view, are the optical components of the laser rangefinder 10 , in particular the transmission and the reception path, in the y-direction by an offset distance 74 spaced. In this way, the transmission and reception paths are independent of each other, so that the emitted laser radiation 30 optically from the received laser radiation 30 ' is decoupled. Furthermore, such parallax effects can be avoided, which can make evaluation of the received measurement signals more difficult.

In the operating mode in which the laser range finder 10 scanning, ie the laser radiation 30 by means of the projection device 20 the transmitting device 28 the angular range α (reference numeral 46 ) is periodically scanned (cf. 3 ), always only one laser point at any one time 48 the visual field of the receiving optics 56 from the angular range γ ( 60 ) illuminated. This is the laser point 48 typically in the angular range σ ( 66a -E) one, in particular a single, facet 64a e. In the in 4a shown constellation is the laser point 48 (if on a target object 34 projected) in the angular section area σ of the fourth facet from the left (facet 64d ) and from this to the detector element 22 ' displayed.

The graphic representation of the 5b Represents the dependency of the position 76 of the target object 34 projected laser spot 48 the emitted laser radiation 30 from the outside angle 40 of the emitted laser beam 30 (Optical transmission angle) in the projection plane - and thus indirectly from the tilt angle of the micromirror 38 ' (mechanical deflection angle) - dar. The mechanical tilt angle is thereby half the value of the optical emission angle 40 given. The ordinate of the graphic in 5b is given in arbitrary units.

5a shows in an analogous way the position 78a -E each by means of the five facets 64a -E on the detector element 22 ' pictured points of light 80 depending on the transmission angle 40 of the emitted laser beam 30 (Optical transmission angle) in the projection plane - and thus again indirectly from the tilt angle of the micromirror 38 ' (mechanical deflection angle) - dar. Here, every facet forms 64a -E the on the target object 34 projected laser spot 48 over an angular range σ ( 66a -E) of at least 12 degrees on the detector element 22 ' from. The whole, on the detector element 22 ' Imaged angular range γ ( 60 ) is the sum of the angular sections σ ( 66a -E) at 60 degrees. Each optical transmission angle 40 the laser radiation 30 can a position 78a -E of the pictured point of light 80 on the detector element 22 ' be clearly assigned.

Advantageously, a unique association between image on the detector device 22 and laser point 48 on the target object 34 - ie between the point of light 80 on the detector device 22 and the optical transmission angle 40 the emitted laser radiation 30 - be enabled.

The faceted look 62 of the laser rangefinder 10 is designed with regard to its focal length such that the focusing optical facets 64a -E received laser radiation 30 ' so on the SPAD array 58 the detector device 22 project that at least 2 × 2 SPADs 58 ' of the SPAD array 58 be illuminated. This is schematically in 5c based on a section of the SPAD array 58 with a plurality of SPADs 58 ' shown, wherein at least 2 × 2 SPADs 58 ' of the SPAD array 58 from the point of light 80 incident laser radiation 30 ' be illuminated. The arrangement of the four illuminated SPADs 58 ' in 2 × 2 arrangement is in 5c with reference number 88 characterized.

Using the laser rangefinder 10 It is possible for the operator, distances to several different measuring points, ie in different relative directions 84a . 84b . 84c the laser radiation 30 to determine promptly. In this embodiment, the laser rangefinder allows 10 within a second a plurality of distance measurements in the periodically swept angular range α ( 46 ). The number of distance measurements to be made can be made via a menu using the actuators 16 be set by an operator. In addition, the number of distance measurements to be performed and their relative directions 84a . 84b . 84c , ie its associated angle under which the measurement is performed, automatically by the control device 18 of the laser rangefinder 10 determined and thus be specified internally. Due to the inventive design of the laser rangefinder 10 is a comfortable, indirect measurement of a distance between two inaccessible points on the target object that can only be reached with laser beams 34 possible without the laser rangefinder 10 must be created at one of the points. The route to be determined indirectly becomes, using trigonometric functions, several distance measurements in different relative directions 84a . 84b . 84c between the laser rangefinder 10 and the target object 34 as well as between the relative directions 84a . 84b . 84c included angles from the controller 18 of the laser rangefinder 10 determined. The measurement and / or projection of such a distance is measured with a push of a button within a short period of time, in particular less than one second. The operator may advantageously stay in a spaced-apart position during the measuring process. At the same time, a marking of the distance to be measured in the form of the projected laser line 52 possible.

As in 6a and 6b is shown, the receiving optics 56 in this embodiment also second means 82 in the form of a shutter 26 on, which forms a light-tight, mechanically movable element and in the receiving path of the laser rangefinder 10 between the faceted optics 62 and the detector device 22 located (in 2 shown schematically as a box). The shutter 26 is as one by means of a shutter control 26 ' electrically adjustable focal plane shutter realized and provided, each a single, selectable facet 64a -E do not cover, while all other facets 64a -E the faceted optics 62 be covered light-tight. The viewing window is in 6a and 6b with reference number 86 shown. In this way, only laser radiation 30 ' from selectable angular sub-ranges Ω, which in this exemplary embodiment are identical to selectable angular sub-ranges σ ( 66a -E) of a facet 64a -one 6a facet 64d ; in 6b facet 64c ), individually on the detector device 22 displayed. Electromagnetic radiation passing through the other facets 64a -E would enter the receive path is through the shutter 26 blocked.

The choice of a translucent facet 64a E takes place in a particularly simple embodiment of the second means 82 by changing the position of the shutter 26 , in particular relative to the receiving optics 56 , The shift takes place in discrete steps, each of which has an angle subrange σ ( 66a -E). This is done by comparing the 6b with the 6a clear. Will the opening of the shutter 26 moves, the angular subareas σ ( 66a -E) (generally the angular subdomains Ω) by means of the n facets 64a -E sequentially on the detector device 22 project (here in the order from right to left: angular section 66d , then angle section 66c ).

The choice of the imaging facet 64a -E, ie the associated angular subrange σ ( 66a -E), is with the direction, under the laser radiation 30 by means of the projection device 20 is sent out, coupled. Thus, light transmission from angular sub-ranges σ ( 66a -E), from which no returning laser radiation 30 ' is received during a measurement hidden. In 6a are, for example, the angle sections 66a , b, c and 66e hidden while angular section area 66d is translucent. As a result, the amount of backlight that is used in a measurement process together with backscattered or reflected laser radiation 30 ' on the detector device 22 is projected, significantly reduced and thus reduces the duration of a measurement performed and increases their quality.

7 finally shows in perspective view an alternative embodiment of a laser range finding device according to the invention 10 in the form of a hand held 2D laser rangefinder 10 '' that has a two-dimensional faceted look 90 has, the laser radiation 30 ' can map from two dimensions. The essential components of the invention differ only in that the projection device and the receiving optics 56 are intended to laser radiation 30 emit in two dimensions different relative directions or return laser radiation 30 ' to receive from two dimensions. The laser radiation 30 is transmitted by means of an alternatively configured projection device of the transmitting device, a solid angle range A periodically sweeping. By means of the two-dimensional facet optics 90 is reflected from a solid angle range Г returning laser light for detection on a detector device. The individual facets divide the solid angle range Г into solid angle partial ranges Σ.

In an alternative or additional embodiment of the laser rangefinder 10 this has a non-illustrated position detection unit, which is intended to an orientation of the laser rangefinder 10 and / or the projection device 20 in the room. Using the data determined by the position detection unit in conjunction with a fine motor actuator, the laser range finder 10 and / or the projection device 20 be aligned particularly precise and stable during a measurement process, so advantageously a dithering of the hand of the operator can be damped and / or further information for distance determination and / or orientation can be determined. A position detection unit should in particular be understood to mean a unit which is at least provided with a view of at least the laser distance measuring device 10 and / or the projection device 20 at least relative to gravity. Preferably, the position detection unit is also provided to determine an acceleration in a spatial direction and / or a rotation about an axis, which is aligned for example for determining a horizontal distance parallel to the direction of gravity. For example, the operator could have a vertical and / or horizontal arrangement of a measuring plane of the projection device 20 be issued.

In 8th a process diagram is shown, which is an embodiment of the method according to the invention for determining a distance on a surface of the target object 34 by means of the laser rangefinder 10 illustrated. It is in a first step 100 laser radiation 30 by means of the projection device 20 the transmitting device 28 an angular range α ( 46 ) periodically sweeping over to the target object 34 sent out. In particular, the laser rangefinder transmits 10 upon execution of the process step 100 the laser radiation 30 the angular range α ( 46 ) periodically sweeping out so quickly that on the remote object 34 a projected laser line 52 is pictured.

From the target object 34 returning laser radiation 30 ' is in a second process step 102 by means of the faceted optics 62 on the detector device 22 projected.

In a third process step 104 becomes a distance in that relative direction 84a . 84b . 84c determined in which at this time laser radiation 30 from the laser rangefinder 10 is sent out. Also in this process step 104 the associated transmission angle 40 the relative direction 84a . 84b . 84c , For example, about the deflection angle of the projection device 20 , determined.

In one process step 106 will be the length of the route on the distant object 34 that periodically from the laser radiation 30 is swept, in particular the length of the projected laser line 52 , using trigonometric functions of at least two in different relative directions 84a . 84b . 84c determined distances and between these at least two relative directions 84a . 84b . 84c included angle (for example, determined as the difference of the transmission angle 40 ).

Furthermore, in a further optional method step 108 the track on the target object 34 that periodically from the laser radiation 30 is swept over, in particular the projected laser line 52 , controlled or controlled to a specified length.

The procedure is repeated as in 8th is shown by an arrow.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 10016309 A1 [0002]
• DE 102011005277 A1 [0002]
• DE 102011089325 A1 [0002]

Claims (18)

Laser rangefinder ( 10 . 10 ' . 10 '' ), in particular handheld laser rangefinder ( 10 ' . 10 '' ), with at least one transmitting device ( 28 ) for emitting laser radiation ( 30 ), a receiving optics ( 56 ) for receiving from a remote object ( 34 ) returning laser radiation ( 30 ' ) as well as with at least one detector device ( 22 ) for detecting received laser radiation ( 30 ' ), whereby the laser radiation ( 30 ) by means of a projection device ( 20 ) of the transmitting device ( 28 ) an angular range α ( 46 ) is periodically scanned so that a projected laser line ( 52 ) on the remote object ( 34 ), characterized in that the receiving optics ( 56 ) a laser radiation ( 30 ' ) from an angular range γ ( 60 ) for detection on the detector device ( 22 ) projecting facet optics ( 62 ) having. Laser rangefinder ( 10 . 10 ' . 10 '' ) according to claim 1, characterized in that the facet optics ( 62 ) of a plurality of n facets ( 64a . 64b . 64c . 64d . 64e ) in the form of focusing optical lenses, the n facets ( 64a . 64b . 64c . 64d . 64e ) the angular range γ ( 60 ) in the number n of facets ( 64a . 64b . 64c . 64d . 64e ) corresponding angular sections σ ( 66a -E) and each of the n facets ( 64a . 64b . 64c . 64d . 64e ) the associated angular range σ ( 66a -E) on the detector device ( 22 ) projected. Laser rangefinder ( 10 . 10 ' . 10 '' ) according to one of claims 1-2, in particular according to claim 2, characterized in that the faceted optics ( 62 ) consists of a plurality of spherical or aspheric optical lenses. Laser rangefinder ( 10 . 10 ' . 10 '' ) according to any one of claims 1-3, characterized in that the faceted optics ( 62 ) between neighboring facets ( 64a . 64b . 64c . 64d . 64e ) first means ( 68 . 68 ' . 68 '' ), which is an optical crosstalk of light between facets ( 64a . 64b . 64c . 64d . 64e ) counteract. Laser rangefinder ( 10 . 10 ' . 10 '' ) according to one of claims 1-4, characterized in that the receiving optics ( 56 ) second means ( 82 . 26 ), which allow the angular subareas σ ( 66a -E) over the n facets ( 64a . 64b . 64c . 64d . 64e ) sequentially on the detector device ( 22 ) to project. Laser rangefinder ( 10 . 10 ' . 10 '' ) according to any one of claims 1-5, characterized in that the receiving optics ( 56 ) third means ( 70 ), in particular a spectral filter ( 70 ' ), which allow, from the angular range γ ( 60 ) to at least partially filter incident electromagnetic radiation. Laser rangefinder ( 10 . 10 ' . 10 '' ) according to any one of claims 1-6, characterized in that a maximum angular range α _max ( 48 ' ), in which the laser radiation ( 30 ) by means of the projection device ( 20 ) of the transmitting device ( 28 ) the angular range α ( 46 ) is periodically swept, is at least 30 degrees, preferably at least 60 Degree is, more preferably at least 90 degrees. Laser rangefinder ( 10 . 10 ' . 10 '' ) according to claim 7, characterized in that the angular range γ ( 60 ) greater than or equal to the angular range α _max ( 48 ' ). Laser rangefinder ( 10 . 10 ' . 10 '' ) according to any one of claims 1-8, characterized in that the facet optics ( 62 ) is realized in one piece, in particular as a one-piece injection-molded component or injection-molded component is realized. Laser rangefinder ( 10 . 10 ' . 10 '' ) according to any one of claims 1-9, characterized in that the detector device ( 22 ) at least one SPAD ( 58 ' ), in particular a SPAD array ( 58 ) having. Laser rangefinder ( 10 . 10 ' . 10 '' ) according to claim 10, characterized in that the focusing optical lenses of the facet optics ( 62 ) Laser radiation ( 30 ' ) on a SPAD array ( 58 ) of the detector device ( 22 ) projects that at least 2 × 2 SPADs ( 58 ' ) of the SPAD array ( 58 ). Laser rangefinder ( 10 . 10 ' . 10 '' ) according to any one of claims 1-11, characterized in that the projection device ( 20 ) of the transmitting device ( 28 ) at least one at least one-dimensionally deflectable mirror ( 38 ' ), with the use of laser radiation ( 30 ) under periodically variable relative directions ( 84a . 84b . 84c ) in the angular range α ( 46 ) is sent out. Laser rangefinder ( 10 . 10 ' . 10 '' ) according to one of claims 1-12, in particular according to claim 5, characterized in that the relative direction ( 84a . 84b . 84c ), under the laser radiation ( 30 ) by means of the projection device ( 20 ) is emitted, with the angular range σ ( 66a -E), from the incident electromagnetic radiation on the detector device ( 22 ) is coupled. Laser rangefinder ( 10 . 10 ' . 10 '' ) according to at least one of the preceding claims for use in a vehicle, in particular for use in a motor vehicle. Method for determining a distance on a surface of a remote object ( 34 ) by means of a laser rangefinder ( 10 . 10 ' . 10 '' ), in particular a laser rangefinder ( 10 . 10 ' . 10 '' ) according to one of claims 1-14, in which 30 ) by means of a projection device ( 20 ) a transmitting device ( 28 ) an angular range α ( 46 ) periodically sweeping over to the removed object ( 34 ), • from the remote object ( 34 ) returning laser radiation ( 30 ' ) by means of a faceted optical system on at least one detector device ( 22 ), where distances in different relative directions ( 84a . 84b . 84c ) between the laser rangefinder ( 10 ) and the remote object ( 34 ) and angles between the relative directions ( 84a . 84b . 84c ) and using trigonometric functions of at least two in different relative directions ( 84a . 84b . 84c ) determined distances and between these at least two relative directions ( 84a . 84b . 84c ) included angle the distance on the surface of the removed object ( 34 ) is calculated. Method for determining a distance according to claim 15, wherein the laser radiation ( 30 ) the angular range α ( 46 ) is emitted so periodically sweeping that on the remote object ( 34 ) a projected laser line ( 52 ) is pictured. A method for determining a distance according to any one of claims 15-16, wherein a length of a distance on the remote object ( 34 ), which are periodically interrupted by the laser radiation ( 30 ), in particular the length of the projected laser line ( 52 ), is determined. Method for determining a distance according to one of Claims 15-17, the projection device ( 20 ) in an operating state of the laser distance measuring device ( 10 . 10 ' . 10 '' ) is controlled and / or regulated such that a distance on the remote object ( 34 ), which are periodically interrupted by the laser radiation ( 30 ), in particular the projected laser line ( 52 ), takes a predetermined length.

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