Distance meter for measuring objects

Abstract

The present invention relates to a rangefinder for detecting objects in a monitoring area according to the triangulation principle, comprising a transmitting arrangement for emitting transmitted light signals into the monitoring area, comprising at least one receiving arrangement which includes at least one receiving optic configured for focusing received light signals generated by an object present in the monitoring area through reflection of incident transmitted light signals in at least one receiving light spot, and at least one light receiver configured for converting the at least one receiving light spot into electrical received signals, wherein the point of impact of the received light spot on the at least one light receiver with respect to a triangulation direction depends on the distance of the object from the rangefinder, comprising a fiber optic arrangement which is arranged upstream of the at least one light receiver and is configured toto detect received light and transmit it to at least one light receiver, and with an evaluation unit connected to the at least one light receiver, which is designed to determine the distance of a detected object from the rangefinder on the basis of the electrical received signals, depending on the point of impact of the received light spot on the at least one light receiver and depending on the light travel time of the emitted and received light signals.

Description

[0001] The present invention relates to a rangefinder for detecting objects in a monitoring area according to the triangulation principle, comprising a transmitting arrangement for emitting transmitted light signals into the monitoring area, comprising at least one receiving arrangement which includes at least one receiving optic configured for focusing received light signals generated by an object present in the monitoring area through reflection of incident transmitted light signals in at least one receiving light spot, and at least one light receiver configured for converting the at least one receiving light spot into electrical received signals, wherein the point of impact of the received light spot on the at least one light receiver with respect to a triangulation direction depends on the distance of the object from the rangefinder, and comprising an evaluation unit connected to the at least one light receiver, which is configured toto determine the distance of a detected object from the rangefinder based on the electrical received signals, depending on the point of impact of the received light spot.

[0002] In such a rangefinder, which can also be called a triangulation light sensor or, more generally, a triangulation sensor, the transmitting and receiving arrangements are laterally offset from each other in the so-called triangulation direction, so that the transmitting and receiving axes do not coincide. Such a configuration of a rangefinder is also called a biaxial arrangement.

[0003] In a rangefinder operating on the triangulation principle, the light receiver consists of at least two photosensitive receiving elements or is designed as a so-called line sensor with at least one line of photosensitive elements.

[0004] Depending on the distance between the rangefinder and a reflecting object, the position of a received light spot, generated by the receiving optics arrangement through the shapes of the reflected light (i.e., diffusely or specularly reflected light from the object) on the light receiver, changes in the triangulation direction. There is a unique geometric relationship between the point of impact of the received light spot on the light receiver and the distance to the detected object. By evaluating the light distribution on the light receiver, which can be detected, for example, by the photosensitive elements of a line sensor arranged side by side in a row along the triangulation direction, the distance between the rangefinder and the object can be determined, or it can be established whether a detected object is within a specified distance of the rangefinder.

[0005] If a detected object is located at the operating point of the rangefinder, i.e., the object lies within the set object distance of the receiving optics, the received light spot is a sharp image of a transmitted light spot created by the transmitted light signals on the detected object. If the object is at a distance from the operating point, the received light spot may also be a blurred image of the transmitted light spot.

[0006] Triangulating rangefinders, or more generally, triangulating optoelectronic sensors, are used in particular to detect objects within a monitoring area covered by the rangefinder, taking into account the object's distance from the rangefinder. For this purpose, a corresponding evaluation unit may be provided, which is at least connected to the light receiver and is configured to process electrical signals received by the light receiver by converting the received light signals into electrical signals, and to generate a corresponding object detection signal based on these electrical signals. Such an object detection signal may, for example, include information about the object's distance or it may be generated based on a comparison with a distance threshold.Such a comparison can, for example, include checking whether a determined object distance is greater or less than a specified distance threshold, or whether the determined object distance lies within or outside a specified distance range.

[0007] In conventional rangefinders of the type mentioned above, the optical and electronic components are usually housed in a single casing. The size of this casing is determined not only by the triangulation distance, i.e., the parallax between the transmitting and receiving axes, but also, to a considerable extent, by the space required for the components to be integrated into the casing. Due to the size of conventional rangefinders, their use in confined spaces is often not possible.

[0008] In principle, the triangulation deviation of the received light spot generated on the light receiver, which can be defined as the extent of a change in the position of the light spot when the distance to an object changes by a certain amount, inevitably decreases with increasing distance of the detected object in most optoelectronic sensors based on the triangulation principle due to geometric constraints. Accordingly, the distance resolution and thus the measurement accuracy are high in the near range, but decrease continuously towards the far range.

[0009] In DE 10 2004 037 137 A1 a method for distance measurement is described in which, in addition to a time-of-flight or phase-sensitive detection of the radiation remitted by an object, at least one further optical method for distance measurement is applied.

[0010] DE 10 2004 042 466 A1 describes a device for optical distance measurement which combines a distance measurement carried out according to the phase measurement principle, in which the distance to be sought is determined on the basis of a phase shift between a modulated transmitted light signal and a received light signal reflected by the object, with a triangulation measurement.

[0011] EP 2 278 361 A1 describes an optoelectronic sensor with a transmitting channel and two receiving channels, wherein the transmitting channel and the first receiving channel are arranged collinearly to each other and the second receiving channel forms a triangulation arrangement with the transmitting channel.

[0012] DE 38 07 077 A1 discloses a device for non-contact optical distance measurement using the triangulation method. A measuring head is coupled via an optical fiber and an optical fiber strip to a base unit in which a laser and a receiver element are arranged. The transmitted signals are guided through the optical fiber and the received signals through the optical fiber strip. The receiver element can be configured as a line array of photosensitive semiconductor elements, with each semiconductor element being assigned an optical fiber from the fiber strip.

[0013] From EP 2 711 667 A1 a device for distance measurement is known in which distance determination by triangulation is combined with distance determination by light time-of-flight determination, wherein the light time-of-flight principle is used for greater distances and the triangulation principle for shorter distances in order to improve the measurement accuracy.

[0014] DE 10 2018 222 416 A1 relates to a lidar system in which received light beams generated by various laser sources are detected by a common receiving optic and guided to a corresponding detector via several optical fibers. The optical fibers are linearly fanned out at the input and circularly bundled at the output. According to one embodiment, two bifurcated optical fibers rotating relative to each other are provided, of which a first optical fiber bundles fanned-out strands into concentric rings, and a second optical fiber has corresponding, also concentric rings at the input, which again divide into three separate strands.

[0015] EP 2 216 661 A1 discloses an optical sensor with background suppression in which the received light is guided to a detector unit via two optical receiving fibers spaced at different distances from the transmitting light axis. Depending on the distance of a detected object, different proportions of the light are directed either via the first optical receiving fiber, referred to as the near-field fiber, or via the second receiving fiber, referred to as the far-field or background fiber. The detector unit may contain a differential diode or two individual standard diodes for detecting the light signals transmitted via the different receiving fibers.

[0016] The object of the invention is to provide an improved rangefinder of the type mentioned above, which has a high resolution over a large distance range and can also be used under demanding environmental conditions.

[0017] The problem is solved by a rangefinder with the features of claim 1. According to the invention, a rangefinder for detecting objects in a monitoring area is provided according to the triangulation principle, comprising a transmitting arrangement for emitting transmitted light signals into the monitoring area, comprising at least one receiving arrangement which includes at least one receiving optic, which is configured to focus received light signals generated by an object present in the monitoring area through the reflection of incident transmitted light signals, in at least one receiving light spot, and at least one light receiver, which is configured to convert the at least one receiving light spot into electrical received signals, wherein the point of impact of the received light spot on the at least one light receiver with respect to a triangulation direction depends on the distance of the object from the rangefinder, with a fiber optic arrangement.which is arranged upstream of at least one light receiver and is configured to detect received light and transmit it to at least one light receiver, and with an evaluation unit connected to the at least one light receiver, which is configured to determine, on the basis of the electrical received signals, depending on the point of impact of the received light spot on the at least one light receiver and depending on the light travel time of the emitted and received light signals, a distance of a detected object from the rangefinder.

[0018] The aforementioned time of flight of the emitted and received light signals can be defined, in particular, as the sum of the time of flight of the emitted light signals between emission and arrival at the detected object and the time of flight of the received light signals between reflection by the object and arrival at the light receiver. Taking the speed of light into account, the distance of the object from the rangefinder can be determined from this. Determining the distance of the detected object from the rangefinder as a function of the time of flight of the emitted and received light signals is subsequently also referred to as TOF measurement or distance determination according to the TOF principle. The abbreviation "TOF" stands for the English term "Time of Flight" for the time of flight. Additional signal propagation times in the electronic components used can, for example,can be taken into account computationally or experimentally by means of a prior calibration process.

[0019] The invention uses both the triangulation principle and the time-of-flight principle for distance measurement.

[0020] Examples of light receivers that can be used include photodiodes, avalanche photodiodes, photodiode arrays, SPAD arrays (SPAD: short for Single Photon Avalanche Diode), CMOS arrays or the like.

[0021] By using a fiber optic arrangement in the receiving light path according to the invention, it is possible to position the light receiver, and in particular a circuit board that serves as a carrier and for the electrical contacting of the light receiver and, if applicable, other electronic components required for the operation of the light receiver, at a distance from both the receiving arrangement and the transmitting arrangement. This reduces the space required for the distance meter, at least in an area directly adjacent to the monitoring area, and in particular shifts the additional space requirement resulting from the combination of two different measuring principles to areas further away from the measuring point. The light receiver or...A circuit board carrying the light receiver, and optionally an evaluation unit for the rangefinder, can be positioned remotely from the receiving optics assembly in an area where application-related space constraints are no longer relevant. The length of the optical fiber assembly and the spatial path of the portion of the receiving light path passing through it are subject to only relatively minor restrictions. This allows for the implementation of a curved receiving light path.

[0022] The distance meter according to the invention is therefore not only suitable for space-constrained applications, but also for use under extreme environmental conditions, for example under the influence of high temperatures, e.g. in melting furnaces, strong magnetic fields, for example in MRIs for distance-based determination and subtraction of movements of a human body to be detected, in a vacuum, in a cleanroom, in closed systems (to improve hygiene or cleanability), in liquids or in contaminated environments.

[0023] Advantageously, the evaluation unit combines the distance determined by triangulation and the distance determined based on the time of flight of light in such a way that, for objects in the immediate vicinity, the distance determined by triangulation is primarily used, while for objects located at a distance, the distance determined by the time of flight of light is primarily used. In principle, both distance measurements can also be combined in a suitable manner, for example by averaging or by (subsequently) weighting the two components based on distance.

[0024] Many possible configurations arise from the combination of the two measurement principles, some of which are described below in the form of preferred embodiments. The inventive combination of triangulation measurement, time-of-flight measurement, and fiber optic arrangement is not limited to these embodiments, but expressly extends to other conceivable configurations as well.

[0025] According to an unclaimed embodiment, the receiving arrangement comprises a single light receiver, wherein the evaluation unit and the single light receiver are configured to determine the distance of the detected object from the rangefinder based on the electrical receiving signals generated by the single light receiver, both as a function of the point of impact of the received light spot and as a function of the time of flight of the emitted and received light signals. The single light receiver is designed to be spatially resolved in order to determine the point of impact of the received light spot on the light receiver and is simultaneously configured to be suitable for a time-of-flight (TOF) measurement. It can, for example, be configured as a one-dimensional or two-dimensional array of SPAD elements.Compared to the configuration described below with two light receivers, one responsible for triangulation measurement and the other for TOF measurement, detecting triangulation on a single light receiver configured as a TOF receiver offers advantages in terms of cost and required installation space. Furthermore, this can increase the level or signal-to-noise ratio (SNR) of the received signals.

[0026] According to the invention, the receiving arrangement comprises a first and a second light receiver, wherein the evaluation unit and the first light receiver are configured to determine the distance of the detected object from the rangefinder as a function of the point of impact of the received light spot, and wherein the evaluation unit and the second light receiver are configured to determine the distance of the detected object from the rangefinder as a function of the time of flight of the emitted and received light signals. Thus, the first light receiver is a spatially resolved light receiver and is used for distance measurement according to the triangulation principle, while the second light receiver is used exclusively for time-of-flight (TOF) measurement. Both light receivers are associated with the receiving arrangement.

[0027] It is understood that in both embodiments, the evaluation unit for performing a TOF measurement can additionally be connected to a light source of the transmitting arrangement, for example, to control it for an exact determination of the light transit time or to receive a synchronization signal from the light source, which represents a transmission time of the transmitted light signals. Preferably, the transmitted light signals are emitted in the form of short light pulses, and the light transit time is determined based on the time difference between a transmitted light pulse and a corresponding received light pulse. However, a light transit time measurement based on the phase measurement principle is also possible, in which modulated transmitted light is emitted and the light transit time is determined based on a phase shift between the transmitted and received light.Time-of-flight measurement is also possible using the principle of an FMCW lidar, whereby the transmitted light signals are emitted as frequency-modulated continuous wave signals (FMCW is short for frequency modulated continuous wave).

[0028] According to the invention, the optical fiber arrangement comprises a first optical fiber bundle with a plurality of individual optical fibers, which is configured to transmit an intermediate image of the receiving light spot, generated at the input of the optical fiber bundle, to the light receiver. The first optical fiber bundle is arranged upstream of the individual or the aforementioned first light receiver, wherein the individual optical fibers are arranged within the optical fiber bundle to transmit the intermediate image in an identical or similar form ("similar" in the geometric sense). The first optical fiber bundle can, for example, have a magnifying, reducing, or unchanged image scale. Transmitting an intermediate image of the receiving light spot does not require that the intermediate image be a sharp image of the receiving light spot. Depending on the geometric conditions, this intermediate image can also be a defocused image of the receiving light spot.

[0029] According to a further unclaimed embodiment, the optical fiber arrangement additionally comprises an optical fiber, which is configured as a single optical fiber or as a second optical fiber bundle with a plurality of single optical fibers and is assigned to the second light receiver. The input apertures of this optical fiber and the first optical fiber bundle are preferably arranged adjacent to each other in the triangulation direction. Preferably, the first optical fiber bundle is assigned to the first light receiver.

[0030] According to a further unclaimed embodiment, the optical fiber arrangement and the first and second light receivers are arranged and configured such that a received light spot is detected depending on the distance of the object from the first or the second light receiver, wherein preferably a received light spot generated by an object located in the near field is detected by the first light receiver and a received light spot generated by an object located in the far field is detected by the second light receiver. In this embodiment, the received light signals are thus introduced, depending on the object distance, either into the optical fiber intended for the TOF measurement or into the first optical fiber bundle intended for the triangulation measurement and detected by the respective assigned light receivers.

[0031] According to a preferred embodiment, the receiving arrangement comprises a first receiving optic and a second receiving optic arranged laterally offset from it, wherein the first receiving optic is assigned to the first light receiver and the second receiving optic to the second light receiver. Preferably, the first receiving optic is assigned to the first light guide bundle and the second receiving optic to the additional light guide, which may be configured as a single light guide or as a second light guide bundle. In contrast to the embodiment with only one common receiving optic for the first light guide bundle and the additional light guide, at least in a transition region between the near and far ranges, both receiving channels, i.e., the first and the second light receivers, can be simultaneously illuminated with received light.

[0032] According to the invention, the optical fiber bundle is designed as a forked optical fiber bundle, the individual optical fibers of which are combined in a common bundle on the input side and are divided into a first and a second sub-bundle on the output side such that an intermediate image of the received light spot generated at the input of the optical fiber bundle is transmitted by each sub-bundle in such a way that a respective image of the intermediate image is generated at the output of each sub-bundle, wherein the first sub-bundle is arranged upstream of the first light receiver and the second sub-bundle upstream of the second light receiver. The output-side sub-bundles or branches can be of the same size or of different sizes. The individual optical fibers of the two branches are mixed together in the common input-side sub-bundle.In this configuration as well, the near range can be measured using triangulation measurement with the first light receiver and the associated first partial light beam, and the far range can be measured using TOF measurement with the second light receiver together with the second partial beam.

[0033] According to a further preferred embodiment, the transmitting arrangement comprises at least one light source for generating the transmitted light signals, a transmitting optical fiber downstream of the light source, which has a transmitting path with an input aperture and an output aperture, wherein the transmitting path is configured to pass the transmitted light signals from the input aperture to the output aperture, and at least one transmitting optic downstream of the output aperture of the transmitting path, which is configured to focus the transmitted light signals generated by the light source into a transmitting light spot. The light sources can include, among others, LEDs, lasers, laser diodes, or VCSELs (short for Vertical-Cavity Surface-Emitting Lasers, a type of surface emitter). The transmitting lens can be applied directly to the transmitting optical fiber, for example, by fusing the end of the optical fiber or by a 3D printing process.The wavelength of the transmitted light can be in the visible or non-visible range, for example, in the infrared range. If the wavelength of the transmitted light emitted by a first light source is in the non-visible range, transmitted light with a visible wavelength emitted by a second light source can be coupled into the transmitting light guide. This makes the point of impact of the transmitted light spot visible to the user, particularly for alignment purposes. The coupling of the additional visible transmitted light can be achieved, for example, by designing the transmitting light guide as a forked optical fiber bundle similar to the aforementioned forked receiving optical fiber bundle. This allows the visible and non-visible transmitted light emitted by two different light sources to be appropriately mixed.

[0034] According to a further unclaimed embodiment, the transmitting optical fiber is designed as a forked optical fiber and additionally has a receiving path. In a section facing the transmitting optics, the transmitting path and the receiving path run in a common optical fiber section, while in a section facing away from the transmitting optics, they run in at least two separate optical fiber sections. A first of the separate optical fiber sections is assigned to the light source, and a second of the separate optical fiber sections is assigned to the second light receiver. Thus, the transmitting path and the receiving path assigned to the second light receiver run coaxially in certain sections. In this embodiment, the transmitting optics also serve as the receiving optics for the second light receiver.The forked transmitting optical fiber essentially forms a combined transmitting and receiving optical fiber, whereby at least the receiving path can be considered a component of the aforementioned optical fiber arrangement.

[0035] According to a modification, two separate light sources can be used for triangulation measurement and TOF measurement, preferably employing a triple-branched, combined transmitting and receiving optical fiber. While one branch of the triple-branched optical fiber can be designated for each of the two light sources, a third branch can be assigned to the second (TOF) light receiver.

[0036] In all embodiments, the transmitting optical fiber and / or the optical fiber arrangement, i.e., the first and / or the second optical fiber bundle or the individual optical fiber, are preferably flexible.

[0037] Further advantages of the rangefinder according to the invention and advantageous embodiments will become apparent from the following description of the drawings. The drawings illustrate exemplary embodiments of the invention. The drawings, the description, and the claims contain numerous features in combination. It will be advantageous for those skilled in the art to also consider these features individually and / or combine them into meaningful further combinations.

[0038] They show: Fig. 1 a schematic cross-sectional representation of a rangefinder according to an unclaimed first embodiment, Fig. 2 a schematic cross-sectional representation of a rangefinder according to a second embodiment not claimed, Fig. 3 a schematic cross-sectional representation of a rangefinder according to a third embodiment according to the invention, and Fig. 4 a schematic cross-sectional representation of a rangefinder according to an unclaimed fourth embodiment.

[0039] In the following, identical or similar elements or components are designated with the same reference symbols.

[0040] Fig. Figure 1 shows a distance meter 100 according to a first embodiment, which is set up to detect objects 14.1, 14.2 in a monitoring area 12 that have different distances from the distance meter 100.

[0041] The rangefinder 100 comprises a transmitting arrangement 20 for emitting transmitted light signals into the monitoring area 12 along a transmitted light path which is in Fig. 1 is represented by a transmitting light beam 28. The transmitting light arrangement 20 comprises a light source 22, which can be, for example, an LED, laser, laser diode, or VCSEL. The transmitted light emitted by the light source 22 is guided by means of a transmitting light guide 24 into the interior of a housing 16, in which a transmitting optic 26 is provided that focuses the originally divergent transmitted light into a convergent or at least parallel transmitting light beam 28.

[0042] The rangefinder 100 further comprises a receiving arrangement 30 with a receiving optics arrangement, which in the exemplary embodiment of Fig. 1 is formed by a single receiving optic 44, also arranged in the housing 16, and is configured to focus received light signals or received light beams 31.1, 31.2 into a received light spot. The received light signals or received light beams 31.1, 31.2, which are in Fig. 1, which for the sake of clarity are represented only by the respective center rays of the receiving optics 44, are generated by an object 14.1 or 14.2 present in the monitoring area 12 by remission, i.e. by specular and / or diffuse reflection, of incident transmitted light signals.

[0043] The receiving arrangement 30 further comprises a fiber optic arrangement 34, which in the exemplary embodiment of Fig. 1 is formed by a light guide bundle 36 with a plurality of individual light guides 39 or optical fibers. The received light rays 31.1, 31.2 incident on a light input surface 48 of the light guide bundle 36 are guided by the light guide bundle 36 out of the housing 16 to a light receiver 32 arranged outside the housing 16. The light receiver 32 has several photosensitive elements and is configured on the one hand for spatially resolved detection of the received light spot and on the other hand designed as a TOF sensor. It can be formed, for example, by a one-dimensional or two-dimensional array of SPAD elements. The distance measurement according to the TOF principle can be carried out, for example, by means of an evaluation unit (not shown), which can be coupled to the transmitting arrangement, in particular the light source 22, to determine the distance to an object 14.1, 14.2. The photosensitive elements of the light receiver 32 are arranged in a row extending in a triangulation direction T or form a two-dimensional array.

[0044] The transmitting arrangement 20 and the receiving arrangement 30, in particular the transmitting optics 26 and the receiving optics 44, are arranged apart from each other in the triangulation direction T, so that, according to the triangulation principle, the point of impact of the received light spot on the light input surface 48 or on the light receiver 32 with respect to the triangulation direction T depends on the distance of a detected object 14.1, 14.2 from the rangefinder 100.

[0045] As in Fig. As can be clearly seen, the light beam 31.1 from an object 14.1 present in the distance area strikes the light input surface 48 at an impact point which is spaced in the triangulation direction T from the impact point of the light beam 31.2, which was generated by an object 14.2 present in the near area.

[0046] In the exemplary embodiment of Fig. 1. The individual optical fibers 39 of the optical fiber bundle 36 are aligned parallel and have a constant thickness, so that the distance relationship between the respective points of impact of the received light spots during monitoring between the light input surface 48 and a light output surface 50 of the optical fiber bundle 36 coupled to the light receiver 32 is maintained. Thus, a received light pattern generated inside the housing 16 on the light input surface 48 is transferred to the remotely arranged light receiver 32 true to scale.

[0047] As explained at the beginning, in this and all subsequently described embodiments, other types of light guide bundles 36 can also be used, which change the scale relationship of the received light pattern between the light input surface 48 and the light output surface 50.

[0048] Fig. Figure 2 shows a rangefinder 200 according to a second embodiment, which is similar in many features to the rangefinder 100 of Fig. 1. Therefore, only the essential differences are explained below.

[0049] In the rangefinder 200, the optical fiber arrangement 34 comprises, in addition to the optical fiber bundle 36, an optical fiber 38, which in the exemplary embodiment is configured as a single optical fiber. The optical fiber 38 can alternatively also be configured as a (second) optical fiber bundle. Furthermore, the rangefinder 200 comprises a first light receiver 32.1 and a second light receiver 32.2. The first light receiver 32.1 is associated with the optical fiber bundle 36 and is configured as a spatially resolving light receiver, for example, as a line sensor, and serves to determine an object distance in a first measuring branch according to the triangulation principle. The second light receiver 32.2 is associated with the optical fiber 38 and is configured as a time-of-flight (TOF) sensor and serves to determine an object distance in a second measuring branch according to the time-of-flight principle.

[0050] Due to the arrangement of the optical fiber bundle 36 and the optical fiber 38 offset in the triangulation direction T, the distance determination is carried out in the first or the second measuring branch, depending on the distance. While the received light rays 31.1, 31.2, which are reflected by objects 14.1, 14.2 in a medium distance range or in the near range, strike a light input surface 48.1 of the optical fiber bundle 36 and are detected by the first light receiver 32.1, received light rays 31.3, which are reflected by an object present in the far range (not shown), strike a light input surface 48.2 of the optical fiber 38 and are guided by it to the second light receiver 32.2. Thus, the distances of objects in the near and medium range are determined according to the triangulation principle, while distances of objects in the far range are determined according to the time-of-flight principle.The assignment of the two measuring branches to the different distance ranges is only an example here and can of course be done in other ways.

[0051] Fig. Figure 3 shows a rangefinder 300 according to a third embodiment of the invention. Since the rangefinder 300 also shares many features with the rangefinders 100 and 200 of Fig. 1 and Fig. Since 2 is the same, only the essential differences will be explained below.

[0052] The receiving arrangement 30 comprises, similar to the rangefinder 200, Fig. 2 a first light receiver 32.1, which is designed as a position-resolving light receiver, and a second light receiver 32.2, which is designed as a TOF sensor.

[0053] The optical fiber arrangement 34 comprises, instead of the combination of the optical fiber bundle 36 and the optical fiber 38, a forked optical fiber bundle 36A, whose individual optical fibers 39 are combined in a common bundle on the input side and are divided on the output side into a first and a second sub-bundle 37.1, 37.2 such that an intermediate image of the received light spot generated at the input of the optical fiber bundle 36A is passed through each sub-bundle 37.1, 37.2 in such a way that a respective image of the intermediate image is generated at the output of each sub-bundle. The first sub-bundle 37.1 is arranged upstream of the first light receiver 32.1 and the second sub-bundle 37.2 upstream of the second light receiver 32.2. In the representation of Fig. In 3, the first subbundle 37.1 (with respect to diameter) is smaller than the second subbundle 37.2. According to variations, the size ratio of the subbundles 37.1, 37.2 can also be reversed, or both subbundles 37.1, 37.2 can be the same size.

[0054] The arrangement and orientation of the forked fiber optic bundle 36A with respect to its sub-bundles 37.1, 37.2 and the coupled light receivers 32.1, 32.2 is such that the received beams 31.1 emanating from an object 14.1 in the far range are detected by the second light receiver 32.2 designed as a TOF sensor, while the received beams 31.2 emanating from an object 14.2 in the near range are directed to the first light receiver 32.1 configured as a triangulation sensor.

[0055] Fig. Figure 4 shows a rangefinder 400 according to a fourth embodiment. In this embodiment, individual features of the second embodiment ( Fig. 2) and the third embodiment ( Fig. 3) united. Here too, only the essential distinguishing features are explained below.

[0056] In the rangefinder 400, a combined transmit and receive optical fiber 40 is provided instead of a transmit optical fiber, which is hereinafter also referred to as the combined optical fiber 40. The combined optical fiber 40 is designed as a forked optical fiber and has a receive path in addition to the transmit path. The transmit path and the receive path run in a common optical fiber section 42 in a section facing the transmitting optics 26 and in a section facing away from the transmitting optics, each in one of two separate optical fiber sections 42.1, 42.2, wherein a first optical fiber section 42.1 is assigned to the light source 22 and thus to the transmit path, and a second optical fiber section 42.2 is assigned to the second light receiver 32.2 and thus to the receive path.

[0057] Similar to the 100 rangefinder ( Fig.1) The first light receiver 32.1, in conjunction with the light guide bundle 36, detects received beams 31.1, 31.2, which are emitted by objects 14.1 in the far range as well as by objects 14.2 in the near range. The evaluation of these received beams 31.1, 31.2 is carried out according to the triangulation principle.

[0058] In addition, received beams 31.3, which are emitted by objects 14.1, 14.2 in the direction of the rangefinder 400 regardless of their distance, are also guided by the transmitting optics 26, which here also functions as a further receiving optics, through the common optical fiber section 42 and the optical fiber section 42.2 to the second light receiver 32.2, which is designed as a TOF sensor. A surface of the combined optical fiber 40 facing the transmitting optics 26 thus serves both as a light exit surface for the transmitted light and as a light entry surface 48.2 for the received light, i.e., the received beams 31.3. Reference symbol list 100, 200, 300, 400 rangefinder 12 Monitoring area 14, 14.1, 14.2 Object 16 cases 20. Transmission order 22 Light source 24 transmitting optical fibers 26 transmitting optics 28 transmitting light beams 30 Reception arrangement 31.1, 31.2, 31.3 Receiving light rays 32, 32.1, 32.2 Light receiver 34 Light guide arrangement 36, 36A Fiber optic bundle 37.1, 37.2 Subbundles 38 optical fibers 39 individual light guides 40 combined transmit and receive optical fiber 42, 42.1, 42.2 Fiber optic section 44 Reception optics 48, 48.1, 48.2 Light input area 50 Light output area T Triangulation direction

Claims

[1] Distance measuring device (100, 200, 300, 400) for detecting objects (14.1, 14.2) in a monitoring area (12) according to the triangulation principle, with a transmitting arrangement (20) for sending transmitting light signals into the monitoring area (12), with at least one receiving arrangement (30), which includes at least one receiving optic (44) for focusing received light signals generated by an object (14.1, 14.2) present in the monitoring area (12) by reflecting incident transmitted light signals into at least one receiving light spot, and at least one light receiver (32, 32.1, 32.2) for converting the at least one receiving light spot into electrical received signals, wherein the point of impact of the received light spot on the at least one light receiver (32, 32.1, 32.2) with respect to a triangulation direction (T) depends on the distance of the object (14.1, 14.2) from the rangefinder (100, 200, 300, 400), with a light guide arrangement (34) which is arranged upstream of the at least one light receiver (32, 32.1, 32.2) and is configured to detect received light and to transmit it to the at least one light receiver (32, 32.1, 32.2), and with an evaluation unit connected to the at least one light receiver (32, 32.1, 32.2), which is configured to determine, on the basis of the electrical received signals, as a function of the point of impact of the received light spot on the at least one light receiver and as a function of the light travel time of the emitted and received light signals, a distance of a detected object (14.1, 14.2) from the rangefinder (100, 200, 300, 400), wherein the receiving arrangement (30) comprises a first and a second light receiver (32.1, 32.2), wherein the evaluation unit and the first light receiver (32.1) are configured to determine the distance of the detected object (14.1, 14.2) from the rangefinder as a function of the point of impact of the received light spot, wherein the evaluation unit and the second light receiver (32.2) are configured to determine the distance of the detected object (14.1, 14.2) from the rangefinder (100, 200, 300, 400) as a function of the light travel time of the emitted and received light signals, wherein the optical fiber arrangement (34) comprises an optical fiber bundle (36, 36A) with a plurality of individual optical fibers (39) which is configured to transmit an intermediate image of the received light spot generated at the input of the optical fiber bundle (36, 36A) to the first and the second light receiver (32, 32.1, 32.2), wherein the optical fiber bundle (36, 36A) is designed as a forked optical fiber bundle (36A), the individual optical fibers of which are combined in a common bundle on the input side and are divided on the output side into a first and a second sub-bundle (37.1, 37.2) such that an intermediate image of the received light spot generated at the input of the optical fiber bundle (36A) is passed through each sub-bundle (37.1, 37.2) in such a way that a respective image of the intermediate image is generated at the output of each sub-bundle (37.1, 37.2), and wherein the first sub-bundle (37.1) is prior to the first light receiver (32.1) and the second sub-bundle (37.2) is prior to the second light receiver (32.2). [2] Rangefinder (100, 200, 300, 400) according to claim 1, characterized by, that the transmitting arrangement (20) comprises at least one light source (22) for generating the transmitting light signals, a transmitting optical fiber (24) downstream of the light source (22) which has a transmitting path with an input aperture and an output aperture, wherein the transmitting path is configured to pass the transmitting light signals from the input aperture to the output aperture, and at least one transmitting optic (26) which is downstream of the output aperture of the transmitting path and is configured to focus the transmitting light signals generated by the light source (22) into a transmitting light spot.

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