EP3380868A1

EP3380868A1 - Laser distance measuring apparatus

Info

Publication number: EP3380868A1
Application number: EP16770932.8A
Authority: EP
Inventors: Hartmut Spennemann; Boris Riedel; Bernd Schmidtke
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 2015-11-23
Filing date: 2016-09-27
Publication date: 2018-10-03
Also published as: CN108351416A; WO2017089006A1; DE102015223024A1

Abstract

A laser distance measuring apparatus (10, 10', 10"), in particular a hand-held laser distance measuring apparatus (10', 10"), is proposed which is based on a device for laser distance measurement comprising at least one transmitting device (28) for emitting laser radiation (30), a receiving optical unit (56) for receiving laser radiation (30') returning from a distant object (34), and comprising at least one detector device (22) for detecting received laser radiation (30'), wherein the laser radiation (30) is emitted by means of a projection device (20) of the transmitting device (28) in a manner periodically sweeping over an angular range α (46), such that a projected laser line (52) can be represented on the distant object (34). According to the invention, the receiving optical unit (56) of the laser distance measuring apparatus (10, 10', 10") comprises a facet optical unit (62) that projects laser radiation (30') from an angular range γ (60) onto the detector device (22) for detection purposes. Furthermore a method for determining a distance on a surface of a distant object (34) by means of the laser distance measuring apparatus (10, 10', 10") is proposed.

Description

description

title

Laser distance measuring device

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 have been proposed, for example, in DE 10 0163 09 A1, in DE 10 201 1 005 277 A1 and DE 10 201 1 089 325 A1.

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 emitted periodically sweeping over an angle range α, so that a projected laser line can be displayed on the remote object. 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 specific function in at least one application and / or operating state, or is designed to do so

To fulfill 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. 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 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 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. Preferably, the transmitting device is provided to emit laser beam in such a way that a laser beam representing the laser beam

Angular range α periodically sweeps. 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 micromirror has a mirror surface greater than 0.5 mm ² , advantageously greater than 1 mm ² , particularly advantageously greater than 2 mm ² . 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 a. The projection device and / or a control device of the laser range finding device is provided for detecting, controlling and / or preferably regulating an angle of the emitted laser radiation, ie in particular a curvature between relative directions of the emitted laser radiation. 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 angle 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 Thus, the laser beam periodically sweeps over the angle range α, ie it is periodically deflected The periodic sweep of the angle range α takes place in particular with a frequency greater than 20 Hz, preferably greater than 40 Hz, particularly 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 moved so quickly over the target object 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 emitted by the laser beam Laser distance measuring device at least partially detected and used to determine a distance to be measured. The returning laser beam is at least partially detected by means of a detector device for detecting received light, in particular received returning laser radiation. 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 Photon avalanche diode (SPAD) formed 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 for this purpose laser radiation from an angular range γ on the detector device projecting

Facet optics on.

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. Especially

Laser radiation, which is emitted by the projection device at a large transmission angle from the laser rangefinder can be projected by the facet optics on the detector device, so that a distance determination in directions under large deflection of the emitted laser radiation is possible.

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 multiplicity of different ones

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. Under "timely" should in one embodiment In particular, it can be understood that 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 at least two distances within 500 ms, advantageously within 100 ms, particularly advantageously 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 can be estimated and / or calculated and predefined as a function of the angle I range α or the length of the distance to be measured indirectly on the target object.

The inventive design of the laser rangefinder comfortable, indirect measurement of a distance between two achievable only with the laser beam points on the target object is possible with very little design effort, 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 connect with the laser beam determine and output direct distance between the laser rangefinder and the target object.

A "facet optics" is to be understood in particular as a receiving optics which the angular range γ - the so-called visual field of the receiving optics - in

Angular sections σ - and thus in partial fields of view - divides. 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. Can be beneficial to this

Way by means of the facet optics as receiving optics from a remote object returning, i. In particular, reflected and / or scattered, laser radiation from a preferably large Wnkelbereich γ on the detector device, in particular the detector element, projected, preferably imaged.

Advantageously, faceted optics can be used to replace classic, high-intensity and correspondingly expensive wide-angle optics. Such wide-angle optics 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) - a small focal length of, for example f =

10 mm own. 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 Wnkelbereichs γ in Wnkelteilbereiche o, by means of

Facet optics in each case in particular simultaneously on the detector device, in particular its detector element, can be projected, the design-related requirements for the receiving optics for a given angular range γ and predetermined detector size can be significantly mitigated. In the case of the facet optics, each of the curved part regions σ is preferred 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 scanning over the angle 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 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 allows returning laser radiation of the laser beam, which is emitted over the angle range α to scan on the target object, to be received from the entire angular range γ. In one embodiment of the laser rangefinder, the

Facet optics of a plurality of n facets in the form of focusing optical lenses, wherein the n facets the angular range γ in the number n of the facets corresponding angular sections σ divided and each of the n facets the associated angular section σ projected onto the detector device.

Thus, the entire field of view of the receiving optics, i. the angle range Y, divided into n Wnkelteilbereiche σ, wherein each Wnkelteilbereich σ on the detector device, in particular its detector element, projected, is preferably imaged. The projection or imaging of the corresponding angular subareas σ takes place via focusing optical lenses, so that returning laser radiation is preferably imaged focused at large distances onto the at least one detector element of the detector device.

By dividing the field of view or the angle range γ into n partial fields of view or angular partial ranges σ, the focal length of the Increase receiving optics by a factor of n, with simultaneous relaxation of the critical f-number f / # by a factor of n.

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

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 rangefinder, the

Facet optics between adjacent facets first means, which counteract an optical crosstalk of light between the facets.

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

In this context, an "absorber" is to be understood as meaning, in particular, an element which is at least partially provided for absorbing and / or transforming energy, which is preferably to be understood as meaning in particular an element which absorbs radiation, preferably electromagnetic radiation and particularly preferably visible light, and is to be understood as meaning in particular an element with an absorption coefficient 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 o, 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 in the receiving path of the Laser distance measuring device in front of the detector device, in particular in front of the detector element is located.

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 closure, a blind closure, a guillotine closure or in the form of another, a

Experts appear appropriate shutter and / or light modulator, which is intended to cover selectable areas of the receiving optics at least substantially light-tight. 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-transmissive regions of the receiving optics are "activatable." 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

Angle portions Ω, preferably the angular portions σ of the receiving optics - changed in position, in particular can be moved relative to the receiving optics. The displacement can take place either in discrete steps or in a continuous movement. In this way, it is possible in one embodiment of the laser range finding device translucent area, in particular the angle portion .OMEGA., preferably the angle portion o, above or relative to the receiving optics move or scan. 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 curved sections Ω at this point generally designate angular sections of arbitrary extent with Ω <a, so that, for example, a single, several or even partial sections of one or more facets - which in turn each define a curved sections σ - can be covered in a light-tight manner. Preferably, the angular sub-regions Ω represents exactly the angular sub-regions σ of a facet, so that the shutter or shutter allows light to be selectively ("activated") by individual facets or also several facets, while other facets are covered in a light-tight manner and thus light incidence by these covered facets is blocked.

In this way, as a result of a sequential covering of individual regions or individual facets, the adjustable closure allows curved partial regions Ω or in particular the angular partial regions 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 from the

Detector element considered from a Wnkelteilbereich Ω, in particular an angular portion o, for the passage of light remains free. The remaining, covered by the shutter part of Wnkelbereichs γ of the receiving optics is advantageously covered light-tight. Wrd moves the opening of the curtain or the slot, so can the angular portions Ω, in particular the

Angle portions o, project by means of n facets sequentially on the detector device.

Advantageously, it is possible to improve the radiometric performance of at least partial areas of the facet optics by means of light-tight covering Receive optical system by the transmission of the non-relevant for the imaging of an angular range Ω facets or facet portions or facet portions is reduced. 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 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 o, from which incident electromagnetic radiation is projected onto the detector device. In particular, "sendable" means that laser radiation is actually emitted by means of the projection device during operation of the laser range finding device, in particular during a distance measurement. preferably with the Wnkelteilbereich o, from the 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 can be reduced.

In particular, by an actively controlled, preferably scanning second means such as a shutter, shutter, LC display or the like, the 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 can 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, thereby the signal-to-noise ratio in the Clearly improve distance measurement, especially increase significantly. 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 rangefinder, the

Receiving optics third means, in particular a spectral filter, which allow at least partially to filter from the angular range γ incident electromagnetic radiation. 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, in this way incident radiation, which initially consists of backscattered or reflected laser radiation and other radiation contributions, in particular background light or the like, at least partially to the interest

Laser radiation can be reduced. 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 angular range c, in which the laser radiation is emitted 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 accordingly designed to deflect the laser beam in a maximum angular range cw of at least 30 degrees, preferably of at least 60 degrees, particularly 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 Wnkelbereich 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 c specifies the technically possible angular range for the deflection of the laser radiation, i. the Wnkelbereich in which the laser radiation the Wnkelbereich α periodically sweeping can be sent out. The maximum angular range c is therefore not to be confused with the basically arbitrary angular range a, in which the actual, periodic deflection (scanning) of the laser beam takes place. In particular, the laser beam can thus be emitted periodically over the entire angle range α (α <cw) within the maximum angular range c, for example an angular range of 5 degrees, of 13 degrees, of 26 degrees or the like, up to ömax

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 rangefinder, the angular range γ is greater than or equal to the maximum angular range cw. 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 <cw 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 cw of the projection device, so that returning laser radiation of each laser beam emitted in an arbitrary direction of the angular range α within the maximum angular range cw is detected by the receiving optics and for detection by 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-related 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 highly curved surfaces, design of the individual facets 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 is the facet optics manufactured 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 subarea σ onto the detector element, the point of light of the returning one projected onto the detector element moves

Laser beam depending on the direction in which the laser radiation is emitted, via the detector element. 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 may be due to a unique association between the image on the detector device and the laser spot on the target object - i. between

Light spot on the detector device and the optical transmission angle of the emitted laser radiation - to be resolved.

In one embodiment of the laser range finder, the focusing optical lenses of the facet optic project laser radiation onto the beam

SPAD array of the detector device that at least 2x2 SPADs of the SPAD array are illuminated. In particular, at least 2x2 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, the illumination of a plurality of SPADs, in particular of at least 2 × 2 SPADs of the SPAD array, is important if the SPADs of the SPAD array used have a low fill factor, ie a low ratio of light-sensitive to light-insensitive surfaces.

The requirement for illumination of at least 2 × 2 SPADs of the SPAD array can be achieved in one embodiment via the adjustment of the focusing optical lenses of the facet optics or via 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 region Γ is projected onto the detector device for detection, preferably being imaged. The individual facets divide the solid angle range Γ into solid angle partial ranges Σ.

Furthermore, a method according to the invention for determining a distance on a surface of a remote object by means of the invention

Laser rangefinder proposed in the

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 emitted by means of a laser beam steering means continuously over a particular constant, preferably predeterminable, angle range a. 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 high periodic repetition rate of the deflection of the laser beam, the projected laser beam on the target object is 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 , which corresponds in particular to the route 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 and the angle enclosed between these at least two relative directions.

In one embodiment of the method for determining a distance, the projection device is in an operating state of the

Laser distance measuring device controlled and / or controlled such that the distance on the remote object, which is swept periodically by the laser radiation, in particular the projected laser line, assumes a predetermined 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 the distance of the endpoints, between which the emitted laser beam is periodically reciprocated, first determined and compared with the, in particular from the operator, predetermined length value. 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 range finding device according to the invention in the form of a hand-held 1 D-line laser rangefinder FIG. 2 Schematic sectional view of the hand-held 1 D line

Laser rangefinder of Figure 1

FIG. 3 is a schematic plan view of the hand-held 1 D line

Laser distance measuring device of Figure 1, which is located in an exemplary environment to be measured

Figure 4 Schematic representation of beam paths in one

Embodiment of the laser range finding device (a) according to the invention in side elevation and (b) in front elevation

FIG. 5 shows the 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

Figure 6a, b Schematic representation of beam paths in one

Embodiment of the laser rangefinder according to the invention with a closure in side-view Figure 7 Perspective view of an alternative embodiment of the laser range finding device according to the invention in the form of a hand-held laser rangefinder

Figure 8 embodiment of a method according to the invention for

Determining a distance on a surface of a distant object.

Description of the embodiments

FIG. 1 shows a perspective view of an exemplary embodiment of a laser range finding device 10 in the form of a hand-held 1 D-line laser rangefinder 10 ', which can be used, for example, for activities in the field of craftsmanship, for example in the measurement of objects or interior spaces. Such an application in the context of an exemplary measurement constellation is shown in a schematic plan view in FIG. 3, in which the hand-held laser range finding device 10 is used in an environment to be measured. The essential components of the laser range finding device 10 are shown schematically in a sectional view of the laser rangefinder 10 in FIG.

The principles of the hand-held 1-line laser range finding device 10 'described below with reference to the figures can also be applied to other embodiments of a laser range finding device 10 according to the invention that can perform similar or different tasks. In particular, the principles are also applicable to stationary and integrable laser range finders 10, such as laser range finders 10 integrated into motor vehicles, which are used to measure distances during navigation of the motor vehicle and / or in connection with a safety device of the motor vehicle. As shown in FIG. 1, the laser range finding device 10 has a housing 12, a display 14 and actuating elements 16, 16 'for switching the laser range finding device 10 on and off and for starting or configuring a measuring process. Furthermore, the laser range finding device 10 has a power supply device not shown in detail, in particular a battery or an accumulator, preferably a lithium-ion accumulator, for its power supply. The housing 12 accommodates the relevant and / or useful components of the laser range finding device 10 for the operation of the laser range finding device 10. The housing 12 preferably encloses these components and thus protects them against penetration by

Impurities, moisture and mechanical action as a result of shocks or the like.

The laser range finder 10 is operated by using a control device 18 for driving the functional components of the

Laser rangefinder 10 operated. The control device 18 is connected to these components by signal technology. The control device 18 should in particular be understood to mean a device having at least one control electronics, the means for communication with the other components of the laser range finding device 10, for example means for controlling and / or regulating a projection device 20 and / or data processing means and / or further Professional has deemed appropriate means. The control device 18 sets operating function parameters of the laser distance measuring device 10 as a function of at least one operator input and / or an evaluation result of a measurement. By the control electronics of the control device 18 is meant, for example, a processor unit 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 are arranged on a printed circuit board (printed circuit board) and preferably designed in the form of a microcontroller. The controller 18 allows the laser range finder 10 to be controlled and enabled to operate. The control device 18 communicates with the other functional components of the laser range finding device 10, in particular at least one projection device 20, a detector device 22, a Data interface 24, in particular the display 14 and the actuators 16, 16 ', as well as a shutter control 26' and other, the skilled person appear appropriate components. The hand-held laser range finder 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 a detail shown in Figure 2

Transmitting device 28 for generating and emitting time-modulated laser radiation 30. The transmitting device 28 comprises 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 distance measuring device 10 to a target object 34 (see in particular Figure 3) is transmitted in the operation of the laser rangefinder 10 substantially collimated laser radiation 30 via a transmitting optics 36 of the transmitting device 28 in the direction of the target object 34. The transmitting optics 36 consists in the embodiment of the hand-held illustrated in FIG

Laser distance measuring device 10 from lenses 36b, 36c, a beam collimator 36d and an integrated into the housing 12 of the laser rangefinder 10 exit window 36a. In an alternative exemplary embodiment, the transmitting optics 36 may also comprise other beam-shaping and / or beam-directing and / or optical properties influencing the properties of the laser radiation 30

Elements, for example lenses, filters, diffractive elements, mirrors, reflectors, optically transparent panes or the like, have.

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

The micromirror 38 'is connected to an actuator 44, in this case an electrostatic actuator which is actuated using a control unit 20' of the projection device 20, so that the micromirror 38 'is defined in one-dimensional direction and, in particular, continuously swiveled over an angular range of at least 30 ° can be deflected. In particular, panning is to be understood as panning with steps of less than 0.005 degrees. In this way, by means of the control unit 20 'of the projection device 20, the transmission angle 40 at which the laser radiation 30 is emitted from the housing 12 of the laser rangefinder 10 can be predetermined and adjusted in particular one-dimensional direction, in particular controlled and / or regulated. Since the micromirror 38 'can be pivoted in one-dimensional direction, the laser radiation 30 emitted in various relative directions 84a, 84b, 84c biases a projection plane ("laser fan").

The control unit 20 'of the projection device 20 allows the angle at which the laser radiation 30 is emitted relative to the laser range finder 10 or a reference direction 42 to be adjusted. For this purpose, the control unit 20 'an information input, an information processing, a

Information output, a processor and stored in a memory of the control unit 20 '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 'outputs at least one parameter which is intended to control the actuator 44 of the

Laser beam steering means 38 for adjusting the relative direction 84a, 84b, 84c to control and / or to regulate.

By means of the projection device 20 shown in FIGS. 2, 4, 6a and 6b, in at least one operating mode of the laser distance measuring device 10 in succession the control of the actuator 44 by the control unit 20 'of the micromirrors 38' continuously, in particular periodically, swivels and defines the laser radiation 30 between two relative directions 84a, 84b, 84c which define and limit an angular range α (see FIG , is continuously swung back and forth. As shown in FIG. 3, by continuous, periodic pivoting of the micromirror 38 'in a range of deflection of the mirror of up to ± 15 degrees, the emitted laser radiation 30 can also be continuous over a range of angles α (reference 46) of up to 60 degrees be pivoted, in particular be pivoted periodically. The emitted laser radiation 30 lies in the so-called projection plane. In particular, the projection plane is defined by those two laser beams (in relative directions 84a, 84b in FIG. 3) of the laser radiation 30, which are emitted with positive and negative full excursion of the micromirror 38 '.

If the laser radiation 30 is projected onto a target object 34, as shown in FIG. 3, as a result of the continuous pivoting of the micromirror 38 ', a laser spot 48 projected onto the target object 34 by means of the laser radiation 30 moves continuously over the surface of the target object 34 3 represents a bidirectional arrow 50, which symbolizes the periodic swinging back and forth of the laser point 48. Thus, the emitted laser radiation 30 sweeps over the angular range α (46) periodically, in particular in a periodic and / or cyclical reciprocating motion. The periodic sweep of the Wnkelbereichs α (46) takes place with a frequency greater than 20 Hz. In this case, the laser beam 30 projected onto the target object 34 laser point 48 is so quickly moved over the target object 34 that a viewer on the target object 34 is a projected, solid and continuously lit projection line or laser line 52 perceives. In other words, in at least one operating mode of the laser range finder 10, the laser radiation 30 is temporally scanned toward a target 34, so that a one-dimensional laser line 52 is projected on the target 34 and thus becomes visible to an operator of the laser range finder 10. Furthermore, the control unit 20 'of the projection device 20 is provided to regulate the laser beam steering means 38, in particular the actuator 44, in an operating mode of the laser rangefinder 10 such that the projected laser line 52 assumes a predetermined length. In this way, an operator of the laser range finding device 10 can particularly comfortably display and check distances on the target object 34. 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 can be predetermined by the operator by means of the actuating elements 16, in particular by means of an input unit 16 'provided for inputting angles.

An operating mode is to be understood as an operating state which can be influenced by an operator, at least one operating state of the control device 18, 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 determines a distance of the two end points 54a, 54b of the laser line 52 from one another, compares the determined distance with the distance preset by the operator (in FIG. 3: 2.00 m) and then the Angle between the relative directions 84a, 84b defining the end points 54a, 54b of the laser line 52 such that the end points 54a, 54b are arranged at a predetermined distance from each other. A determination of the distance of the two end points 54a, 54b of the laser line 52, and thus the length of the laser line 52, is preferably indirectly using trigonometric functions of several distance measurements in different relative directions 84a, 84b, 84c between the laser rangefinder 10 and the target object 34 and Determined between the relative directions 84a, 84b, 84c Wnkeln determined (see in particular Figure 3). The laser radiation 30 'reflected and / or backscattered by a surface of the target object 34 (not shown in detail here, see FIG. 5c) is imaged on a detector element 22' of a detector device 22 via a receiving optics 56 of the laser rangefinder 10 and detected there. The detector device 22 together with the detector element 22 'is shown in FIG.

In this exemplary embodiment-and in particular also in the exemplary embodiments illustrated in FIGS. 4, 6 a, 6 b-the detector device 22 comprises a SPAD array 58 as detector element 22 '(cf., in particular, FIG. 5 c). The SPAD array 58 has an elongated shape in the direction of the projection plane. For example, the amount

Dimensions of the SPAD array 58 in the projection plane 10 mm and perpendicular to this 1 mm. Depending on an incident light intensity, in particular laser radiation intensity, the SPAD array 58 delivers a spatially resolved detection signal. For this purpose, the SPAD array 58 consists of a multiplicity of uncoupled or coupled, in particular couplable, SPADs 58 '. In one

Embodiment, the SPAD array 58 500 ^χ 50 photosensitive SPADs 58 'on. The detector device 22 is signal-wise connected to the control device 18 of the laser range finding device 10 for the transmission of detection signals.

From a returned between the emitted laser radiation 30 and the surface of the target object 34, i. By means of the control device 18 of the laser range finding device 10, in particular an evaluation unit of the control device 18, a light transit time can be determined and the distance between the laser range finder 10 and the point of impact on the target object 34 can be determined via the speed of light. The determined distance corresponds to the distance of the laser distance measuring device 10 from the target object 34 in the direction of the laser radiation 30 emitted at that time onto the target object 34

Detection signals of distance measurement values determined by the control device 18 in the direction of the emitted laser radiation 30 are then further processed by the control device 18 of the laser range finding device 10 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. Alternatively or additionally, the distance measurement value can also be transmitted for further processing using the data interface 24 to another device, for example a mobile data processing device such as a smartphone, a tablet, a PC, a computer or the like.

As already indicated in FIGS. 1-3 and shown in greater detail in FIGS. 4, 6a and 6b, the laser range finding device 10 according to the invention has a receiving optical system 56 which comprises at least one laser radiation 30 'from a

Angle range γ (60) for detecting on the detector device 22 projecting facet optics 62 includes. In this case, the angular range γ (60) of the receiving optics 56 includes the angular range α (46) into which laser radiation 30 is emitted or can be emitted by means of the projection device 20. In other words, the angle range γ (60) encompasses the angular range c (itself not shown in greater detail), which represents the maximum range of angles α (46) that can be swept by laser radiation 30 from 60 degrees here. As will be explained in connection with FIG. 5a, the facet optic 62 in an exemplary embodiment has an angular range γ (60) of 60 degrees, from which the returning laser radiation 30 'can be projected onto the detector device 22. For this purpose, the facet optics 62 consists of five facets 64a, 64b, 64c, 64d, 64e (hereinafter also: 64a-e) in the form of focusing, in particular spherical or aspherical, optical lenses. Each facet 64a-e images a tilting portion σ (reference numerals 66a-e) of 12 ° onto the detector apparatus 22. The facet optic 62 is economically simple and inexpensive to manufacture as a one-piece injection molding component in an injection molding process. The material of the faceted optics 62 is preferably a transparent glass or plastic material, for example polymethylmethacrylate. The facet optic 62 represents a single component whose facets 64a-e can not be disengaged without destroying the facet optic 62.

It should be noted that the aforementioned numerical values regarding the facet optics 62 such as 60 degrees, 12 degrees, and the like in this embodiment are merely exemplary selected preferred values of this embodiment represent. Deviating values which appear reasonable to a person skilled in the art for the angular range γ (60) and the maximum swept angular range c are conceivable. It should also be noted that the transmitting and receiving optics of the embodiment shown in Figures 1-3 of the laser rangefinder 10 in the projection plane are adjacent to each other, while in the embodiment shown in Figures 4 and 6, the transmitting and receiving optics perpendicular to the projection plane side by side are arranged. Facet optic 62 has first ones between adjacent facets 64a-e

Means 68 in the form of an absorber 68 'and / or filters 68 ", which counteract optical crosstalk of light between the facets 64a-e. The absorbers 68' and / or filters 68" are each as one completely between each adjacent facets 64a-e of the receiving optics 56 extending separating layer executed (see in particular Figures 4a and 4b).

Furthermore, the facet optics 62 have third means 70 in the form of a spectral color filter 70 'which are not shown in greater detail on their surface and allow at least partial filtering of incident electromagnetic radiation from the angular range γ (60). Using the first and third means, spurious background radiation, which has a detrimental effect on the accuracy of measurement results, is advantageously reduced.

In FIGS. 4 a and 4b, the essential optical components of the laser range finding device 10 - projection device 20 with micromirror 38 ', detector element 22' and facet optics 62 - are shown schematically in one

Side view (the considered xz plane corresponds to the projection plane) or a front view (xy plane). Laser radiation 30 is first formed into a focused laser beam or laser beam by means of lenses 36b, 36c and a collimator 36d. This laser radiation 30 shaped in this way is deflected by the micromirror 38 'and emitted at a given time at a defined angle relative to a reference direction 42 from the laser range finding device 10. The curved partial regions σ (66a-e) which are projected onto the detector element 22 'by each facet 64a-e of the facet optical system 62 are represented by dashed lines in the context of geometrical optics, which show the respective angular partial regions σ (66a). e) define. The sum of the angle subareas σ (66a-e) spans the angular range γ (60).

As shown in Figure 4b in the front view, the optical components of the laser range finder 10, in particular the transmitting and

Receive path, spaced in the y direction by an offset distance 74. In this way, the transmission and reception paths are independent of one another, so that the emitted laser radiation 30 is optically decoupled from the received laser radiation 30 '. 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 is scanning, i. E. If the laser radiation 30 is emitted periodically by the projection device 20 of the transmitting device 28 (see Fig. 3), only one laser point 48 of the field of view of the receiving optics 56 is illuminated from the angular range γ (60) at each time point , In this case, the laser point 48 is typically located in the angular range σ (66a-e) of one, in particular a single, facet 64a-e. In the constellation shown in FIG. 4a, the laser point 48 (if projected onto a target object 34) is located in the angle subarea σ of the fourth facet from the left (facet 64d) and is imaged by this onto the detector element 22 '.

The graph of Figure 5b illustrates the dependence of the position 76 of projected on the target object 34 laser point 48 of the emitted laser radiation

30 of the emission 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) -. The mechanical tilt angle is given by half the value of the optical transmission angle 40. The ordinate of the graph in FIG. 5b is given in arbitrary units.

FIG. 5a shows in an analogous manner the position 78a-e of the light spots 80 respectively imaged on the detector element 22 'by means of the five facets 64a-e as a function of the emission angle 40 of the emitted laser beam 30 (optical In this case, each facet 64a-e forms the laser point 48 projected onto the target object 34 over an angular sub-range σ (66a-e) of at least 12 Degrees to the detector element 22 'from. The entire, on the detector element 22 'mapped

Angular range γ (60) is given as the sum of the angular parts σ (66a-e) of 60 degrees. Each optical transmission angle 40 of the laser radiation 30 can be unambiguously assigned a position 78a-e of the imaged light point 80 on the detector element 22 '.

Advantageously, a unique association between the image on the detector device 22 and the laser spot 48 on the target object 34 - i. between light spot 80 on the detector device 22 and the optical transmission angle 40 of the emitted laser radiation 30 - are possible.

The facet optics 62 of the laser range finder 10 is designed with respect to its focal length such that the focusing optical facets 64a-e project laser radiation 30 'onto the SPAD array 58 of the detector device 22 such that at least 2x2 SPADs 58' of the SPAD array 58 are illuminated , This is shown schematically in FIG. 5c with reference to FIG

Section of the SPAD array 58 with a plurality of SPADs 58 'shown, wherein at least 2x2 SPADs 58' of the SPAD array 58 of the light spot 80 incident laser radiation 30 'are illuminated. The arrangement of the four illuminated SPADs 58 'in a 2x2 arrangement is identified by reference numeral 88 in FIG. 5c.

Using the laser range finder 10, the operator is able to travel distances to several different measurement points, i. in various relative directions 84a, 84b, 84c of the laser radiation 30 to determine promptly. In this embodiment, this allows

Laser rangefinder 10, within a second a plurality of distance measurements in the periodically swept angular range α (46) perform. The number of distance measurements to be made can be adjusted via a menu using the actuators 16 by an operator. In addition, the number of performed Distance measurements and their relative directions 84a, 84b, 84c, ie their associated angle at which the measurement is performed, automatically determined by the control device 18 of the laser rangefinder 10 and thus be specified inside the device. The embodiment of the laser range finding device 10 according to the invention allows a comfortable, indirect measurement of a distance between two inaccessible points on the target object 34 that can be reached only with laser beams, without having to apply the laser range finder 10 at one of the points. The distance to be determined indirectly is determined by using trigonometric functions from a plurality of distance measurements in different relative directions 84a, 84b, 84c between the laser rangefinder 10 and the target 34 and the angles included between the relative directions 84a, 84b, 84c by the control device 18 of the laser rangefinder 10. 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 route to be measured in the form of the projected laser line 52 is possible.

As shown in FIGS. 6a and 6b, the receiving optics 56 in this exemplary embodiment also have second means 82 in the form of a shutter 26, which forms a light-tight, mechanically movable element and is located in the receiving path of the laser rangefinder 10 between the facet optics 62 and the detector device 22 is (shown schematically in Figure 2 as a box). Shutter 26 is realized as a slot shutter which can be set electrically by means of a shutter control 26 'and is intended not to cover a single, selectable facet 64a-e, while all other facets 64a-e of facet optic 62 are covered in a light-tight manner. The viewing window is shown in Figure 6a and 6b with reference numeral 86. In this way, only laser radiation 30 'of selectable angular portions Ω, which are identical in this embodiment with selectable Wnkelteilbereichen σ (66a-e) of a facet 64a-e (in Figure 6a facet 64d, in Figure 6b facet 64c), individually on the Detector device 22 shown. Electromagnetic radiation, the would enter the receive path through the further facets 64a-e is blocked by the shutter 26.

The choice of a translucent facet 64a-e is made 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 displacement takes place in discrete steps, each corresponding to an angular range σ (66a-e). This becomes clear by a comparison of FIG. 6b with FIG. 6a. When the opening of the shutter 26 is moved, the rolling portions .sigma. (66a-e) (generally the

Angular portions Ω) by means of the n facets 64a-e sequentially project onto the detector device 22 (here in the order from right to left: angular section 66d, then angular section 66c). The choice of the imaging facet 64a-e, i. of the associated

Angled portion range σ (66a-e) is coupled to the direction under which laser radiation 30 is emitted by means of the projection device 20. Thus, light transmission from angular portions σ (66a-e), from which no returning laser radiation 30 'is received, is blanked out during a measurement. In FIG. 6a, for example, the angle sections 66a, b, c and

66e hidden while angular portion 66d is translucent. Consequently, the amount of backlight that is projected onto the detector device 22 during a measurement process together with backscattered or reflected laser radiation 30 'is significantly reduced, thus reducing the duration of a measurement performed and increasing its quality.

Finally, FIG. 7 shows a perspective view of an alternative embodiment of a laser range finding device 10 according to the invention in the form of a handheld 2D laser rangefinder 10 "comprising a two-dimensional facet optic 90, the laser radiation 30 'of two

Can map dimensions. The components essential to the invention differ only in that the projection device and the receiving optics 56 are provided to receive laser radiation 30 in different relative directions with respect to two dimensions or to receive returning laser radiation 30 'from two dimensions. The Laser radiation 30 is emitted by means of an alternatively configured projection device of the transmitting device a solid angle range A periodically sweeping. By means of the two-dimensionally configured facet optics 90, laser light returning from a solid angle range Γ is imaged for detection on a detector device.

The individual facets divide the solid angle range Γ into solid angle partial ranges Σ.

In an alternative or additional embodiment of the laser range finding device 10, this has a non-illustrated

Location detection unit, which is intended to detect an alignment of the laser rangefinder 10 and / or the projection device 20 in space. Using the data determined by the position detection unit in conjunction with a fine-motor actuator, the laser rangefinder 10 and / or the projection device 20 can be aligned very precisely and stably during a measurement process, so advantageously a dithering of the hand of the operator attenuated and / or further information for distance determination and / or orientation can be determined. A position detection unit is to be understood in particular as meaning a unit which is at least provided to detect a view of at least the laser range finding device 10 and / or the projection device 20 at least relative to the force of 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, a vertical and / or horizontal arrangement of a measuring plane of the projection device 20 could be output to the operator. FIG. 8 shows a method diagram illustrating 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 range finding device 10. In this case, in a first method step 100 laser radiation 30 by means of the projection device 20 of the transmitting device 28 is an angle range α (46) periodically sweeping towards the target object 34 sent out. In particular, when performing the method step 100, the laser range finder 10 emits the laser radiation 30 periodically sweeping the angular range α (46) so fast that a projected laser line 52 is displayed on the remote object 34.

Laser radiation 30 'returning from the target object 34 is projected onto the detector device 22 in a second method step 102 by means of the facet optical system 62.

In a third method step 104, a distance is determined in that relative direction 84a, 84b, 84c into which laser radiation 30 is emitted by the laser range finding device 10 at this time. Also, in this method step 104, the associated transmission angle 40 of the relative direction 84a, 84b, 84c, for example via the deflection angle of the projection device 20, is determined.

In a method step 106, the length of the distance on the remote object 34, which is swept periodically by the laser radiation 30, in particular the length of the projected laser line 52, using trigonometric functions of at least two in different relative directions 84 a, 84 b, 84 c determined distances and the angle enclosed between these at least two relative directions 84a, 84b, 84c (determined, for example, as the difference between the transmission angles 40).

Furthermore, in a further optional method step 108, the path on the target object 34, which is swept periodically by the laser radiation 30, in particular the projected laser line 52, can be regulated or controlled to a predefinable length.

The sequence of the method is repeated, as shown in Figure 8 by an arrow.

Claims

claims

1. A laser rangefinder (10, 10 ', 10 "), in particular hand-held laser range finder (10', 10"), with at least one transmitting device (28) for emitting laser radiation (30), a receiving optical system (56) for receiving from a remote Object (34) returning laser radiation (30 ') and at least one detector device (22) for detecting received laser radiation (30'), wherein 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) can be displayed, characterized in that the receiving optics (56) laser radiation (30 ') from an angular range γ (60) for detection on the detector device (22) has projecting facet optics (62).

2. A laser rangefinder (10, 10 ', 10' ') according to claim 1, characterized in that the facet optics (62) consists of a plurality of n facets (64a, 64b, 64c, 64d, 64e) in the form of focusing optical lenses, wherein the n facets (64a, 64b, 64c, 64d, 64e) divide the angular range γ (60) into the number n of the facets (64a, 64b, 64c, 64d, 64e) corresponding to wobble portions σ (66a-e) and each of n facets (64a, 64b, 64c, 64d, 64e), the associated angular portion σ (66a-e) is projected onto the detector device (22).

3. Laser distance measuring device (10, 10 ', 10 ") according to any 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 aspherical optical lenses.

4. A laser rangefinder (10, 10 ', 10'') according to any one of claims 1 -3, characterized in that the facet optics (62) between adjacent facets (64a, 64b, 64c, 64d, 64e) first means (68, 68' , 68 "), which counteract optical crosstalk of light between facets (64a, 64b, 64c, 64d, 64e).

5. A laser rangefinder (10, 10 ', 10' ') according to any one of claims 1 -4, characterized in that the receiving optics (56) second means (82, 26), which allow the angular portions σ (66a-e) over sequentially projecting the n facets (64a, 64b, 64c, 64d, 64e) onto the detector device (22).

6. Laser distance measuring device (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 Angle range γ (60) to filter incident electromagnetic radiation at least partially.

7. Laser distance measuring device (10, 10 ', 10 ") according to one of claims 1 to 6, characterized in that a maximum angular range c (48') in which the laser radiation (30) by means of the projection device (20) of the transmitting device (28 ) is the angle range α (46) periodically sweeping, at least 30 degrees, preferably at least 60 degrees, more preferably at least 90 degrees.

8. Laser distance measuring device (10, 10 ', 10 ") according to claim 7, characterized in that the angular range γ (60) is greater than or equal to the angular range c (48').

9. Laser distance measuring device (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.

10. Laser distance measuring device (10, 10 ', 10 ") according to any one of claims 1-9, characterized in that the detector device (22) has at least one SPAD (58'), in particular a SPAD array (58).

1 1. A laser rangefinder (10, 10 ', 10'') according to claim 10, characterized in that the focusing optical lenses of the facet optics (62) laser radiation (30') projected onto a SPAD array (58) of the detector device (22) in that at least 2x2 SPADs (58 ') of the SPAD array (58) are illuminated.

12. Laser distance measuring device (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 mounted mirror (38'), with its use Laser radiation (30) is emitted under periodically variable relative directions (84a, 84b, 84c) in the angular range α (46).

13. Laser distance measuring device (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 coupled to the angular portion σ (66a-e) from which incident electromagnetic radiation is projected onto the detector device (22).

14. Laser distance measuring device (10, 10 ', 10 ") according to at least one 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 range finding device (10, 10 ', 10 "), in particular a laser range finder (10, 10', 10") according to one of claims 1-14 the

Laser radiation (30) by means of a projection device (20) of a transmitting device (28) an angle range α (46) periodically sweeping over the remote object (34) out,

• laser radiation (30 ') returning from the remote object (34) is projected onto at least one detector device (22) by means of a facet optical system,

Wherein distances in different relative directions (84a, 84b, 84c) between the laser range finder (10) and the remote object (34) and angles between the relative directions (84a, 84b, 84c) are determined and using trigonometric functions of at least two different ones Relative directions (84a, 84b, 84c) determined distances and the between these at least two Relative directions (84a, 84b, 84c) included angle the distance on the surface of the removed object (34) is calculated.

16. A 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 shown.

17. 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 is swept periodically by the laser radiation (30), in particular the length of the projected laser line (52) determined becomes.

18. A method for determining a distance according to any one of claims 15-17, wherein 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 is swept periodically by the laser radiation (30), in particular the projected laser line (52), a predetermined Length takes up.