OPTICAL DISTANCE SENSOR

Description

[0001] The invention relates to an optical distance sensor.

[0002] These types of optical distance sensors are used to determine the distance to objects and are employed for various measurement or monitoring tasks.

[0003] Optical distance sensors can perform distance measurements, particularly using a pulse-time-of-flight method. The optical distance sensor has a transmitter that emits light beams and sends them into a monitoring area. These light beams are reflected by an object to be detected within the monitoring area and directed back to a receiver of the optical distance sensor. In an evaluation unit, the distance is determined by analyzing the received signals from the receiver, specifically by calculating the time of flight of the light pulses to the object and back to the receiver.

[0004] For distance measurement, integrated time-of-flight modules are advantageously used. These modules employ a VCSEL (vertical-cavity surface-emitting laser) diode or a VCSEL array as the transmitter, emitting laser light in the infrared range. The VCSEL array consists of VCSELs arranged as close together as possible on a single chip. The time-of-flight modules typically use an array of SPADs (single-photon avalanche diodes) as the receiver. These time-of-flight modules offer high performance in a compact form factor.

[0005] The disadvantage here is that such optical distance sensors operate with light beams in the non-visible wavelength range.

[0006] However, visible light beams are required in numerous applications, particularly to be able to optically control the beam guidance of the light beams or to simplify the adjustment of the optical distance sensors during their commissioning.

[0007] In principle, runtime modules with VCSEL diodes or VCSEL arrays that emit light beams in the visible wavelength range can be used to meet this requirement.

[0008] However, a disadvantage is that their resistance to ambient light is an order of magnitude worse than that of VCSEL units that emit infrared light. This leads to a significant reduction in the reliability of the optical distance sensor.

[0009] DE 20 2021 106 330 U1 relates to an optoelectronic sensor comprising at least one measuring light source for emitting at least one measuring light beam in the infrared wavelength range into a monitoring area, at least one pilot light source for emitting at least one pilot light beam in the visible wavelength range into the monitoring area, an optical element for coaxially superimposing the measuring light beam and the pilot light beam, a light receiver for receiving measuring light beams emitted or reflected from the monitoring area and generating corresponding received signals, and a control and evaluation unit for controlling the light receiver, the measuring light source and / or the pilot light source and for evaluating the received signals. The optical element has at least one first optical metasurface for coaxially superimposing the measuring light beam and the pilot light beam.

[0010] In DE 10 2020 106 041 A1, an optoelectronic sensor of the type of a photoelectric sensor is specified, comprising at least one measuring light source for emitting measuring light beams in the infrared wavelength range into a monitoring area, at least one pilot light source for emitting pilot light beams in the visible wavelength range into the monitoring area, an optical element for coaxially superimposing measuring light beams and pilot light beams, a light receiver for receiving measuring light beams remitted or reflected from the monitoring area and generating corresponding received signals, and a control and evaluation unit for controlling the light receiver, the measuring light source and / or the pilot light source and for evaluating the received signals, wherein the optical element for coaxially superimposing measuring light beams and pilot light beams is designed as an optical waveguide.

[0011] The invention is based on the objective of providing an optical distance sensor of the type mentioned above, which on the one hand has a high detection sensitivity and on the other hand enables visual control of the guidance of its light beams.

[0012] The features of claim 1 are provided to solve this problem. Advantageous embodiments and expedient further developments of the invention are described in the dependent claims.

[0013] The invention relates to an optical distance sensor comprising a transmitter emitting light beams in a non-visible wavelength range, a receiver configured to receive light beams reflected from an object, and an evaluation unit designed to determine the object's distance based on received signals from the receiver. A pilot transmitter unit is provided, emitting visible pilot light beams. These pilot light beams are coupled into the path of the light beams by means of coupling means, such that the pilot light beams and the light beams are coaxial with at least partially overlapping cross-sections. A variable aperture is provided, which shapes the pilot light beams to illuminate a portion of the light spot.

[0014] The optical distance sensor according to the invention, or the method for operating this optical distance sensor, achieves high sensor functionality.

[0015] According to the invention, the transmitter of the optical distance sensor emits light beams in the non-visible wavelength range, particularly in the infrared range. This results in high detection sensitivity of the optical sensor when detecting objects in a monitored area. In particular, the optical distance sensor exhibits significantly increased resistance to ambient light compared to an optical distance sensor whose transmitter emits light beams in the visible wavelength range.

[0016] According to the invention, the optical distance sensor comprises a pilot transmitter unit that emits pilot light beams in the visible wavelength range. The pilot light beams are coupled into the beam path by coupling means such that the pilot light beams and the light beams are at least partially overlapping and coaxial, with the coaxial orientation being advantageously maintained throughout the entire monitoring area.

[0017] The visible pilot light beams provide a visualization of the measuring, invisible light beams. This means the user can see the path of the measuring, invisible light beams based on the pilot light beams and thus check their path. This can be used to calibrate the optical distance sensor before commissioning. Furthermore, the user can continuously monitor the path of the light beams during operation following the calibration.

[0018] A key aspect here is that the pilot light beams are not laterally offset, but rather coaxial to the light beams. In the case of the

[0019] With laterally offset pilot light beams, a user would have to employ additional measuring instruments to determine the path of the invisible light beams based on the visible pilot light beams. This effort is eliminated with the optical distance sensors according to the invention, since the pilot light beams are coaxial with the light beams, so that the pilot light beams directly and immediately provide the desired information about the spatial path of the light beams.

[0020] In a particularly advantageous embodiment, the pilot transmitter and the coupling means are designed such that the light beams and the pilot light beams not only run coaxially throughout the entire monitoring area, but also have approximately the same beam cross-section. This has the advantage that the sensor can be aligned without additional aids even if only a portion of the light beams falls on an object in the monitoring area. With only partial overlap of the beam cross-sections of the light beams and pilot light beams, it can happen that the pilot light beams miss an object that is only partially illuminated by the light beams, or conversely, that the pilot light beams strike an object that is missed by the light beams.

[0021] The pilot transmitter unit can emit diffuse or directed, in particular collimated, pilot light beams, wherein the beam characteristic is advantageously adapted to the beam characteristic of the light beams.

[0022] In principle, the distance measurement in the optical distance sensor according to the invention can be carried out using a phase measurement method.

[0023] The transmitter emits light beams in the form of light pulses, which is particularly advantageous. The distance measurement is then carried out using a pulse-time-of-flight method.

[0024] To achieve high performance of the optical distance sensor, integrated components are used as transmitters, with a VCSEL unit being particularly advantageous.

[0025] The VCSEL unit can be formed by a single VCSEL diode emitting only one, preferably directional, light beam. Alternatively, the VCSEL unit can be formed by a VCSEL array emitting multiple light beams. This latter embodiment allows for a particularly large beam angle of the emitted light beams and increases the overall emitted optical power, thus improving the performance of the measurement system.

[0026] Advantageously, and particularly well-suited to the transmitter in the form of a VCSEL unit, the receiver is designed in the form of one or more SPADs (single photon avalanche diodes).

[0027] Instead of a VCSEL, a laser diode (edge ​​emitter) can also be used as the transmitting light source with infrared radiation. This allows for the creation of small light spots with high irradiance.

[0028] According to a first embodiment, the transmitter and the pilot transmitter are each formed by a semiconductor chip, the semiconductor chips being arranged one above the other and fixed relative to each other. For example, the semiconductor chip forming the transmitter can be arranged on top of the semiconductor chip forming the pilot transmitter, the transmitter having a hole in its center as a coupling element through which the pilot transmitter emits the pilot light beams, which then propagate coaxially to the light beams of the transmitter. Of course, the reverse arrangement is also possible, in which the top semiconductor chip with the hole forms the pilot transmitter, with the transmitter emitting the light beams through the hole of the semiconductor chip forming the pilot transmitter.

[0029] According to a further embodiment, a material can be applied to the light-emitting surface of the transmitter, which is designed in the form of a semiconductor chip, in particular a VCSEL array, that converts the infrared light beams of the transmitter into visible pilot light beams. The material does not extend over the entire light-emitting surface of the transmitter, so that the transmitter emits infrared light beams into the monitoring area in the uncovered areas.

[0030] According to a further embodiment, optical fibers are provided as coupling means. The optical fibers are preferably placed around the transmitter so that pilot light beams emitted by the pilot transmitting unit are coupled parallel into the beam path of the light beams via the optical fibers. The optical fibers can also be formed in the form of glass fibers.

[0031] According to a further advantageous embodiment, an optical deflection element is provided as the coupling means.

[0032] The optical deflection element generally deflects pilot light beams from the pilot transmitter unit in such a way that the pilot light beams are coupled coaxially into the beam path of the light beams.

[0033] The optical deflection element is advantageously a dichroic mirror or forms an interference filter.

[0034] This means that the optical deflection element exhibits wavelength-selective properties.

[0035] The optical deflection element can be in the form of a coated glass pane.

[0036] The optical deflection element can be a purely reflective element or can be designed in the form of a beam splitter mirror that reflects light in a first wavelength range and is transparent to light in a second wavelength range.

[0037] In general, it is possible to define the shape of the beam cross-section of the pilot light beams using the optical deflection element.

[0038] In particular, the optical deflection element can be designed such that it reflects only certain portions of the incident pilot light beams. This allows specific patterns of the pilot light beams to be generated, for example in the form of rectangles, rings, or multiple points.

[0039] According to an advantageous embodiment, the size of the light spot of the pilot light rays is adapted to the size of the light spot of the light rays by means of an aperture.

[0040] The aperture can be positioned directly in front of the pilot transmitter unit. Alternatively, the aperture can be positioned at a distance from the pilot transmitter unit.

[0041] According to the invention, a variable aperture is provided by means of which the pilot light rays are shaped in such a way that a part of the light spot of the light rays is illuminated with them.

[0042] An electronically controlled variable aperture is particularly advantageous. Specifically, the variable aperture can be designed as a TFT (thin-film transistor) matrix, in which individual matrix elements can be switched between transparent and opaque. This allows the size and shape of the aperture opening to be set quickly and precisely.

[0043] If the pilot beams are generated by an aperture, the opening angle of the pilot beams can be changed by varying the size of the aperture opening. This allows the pilot beam to be adjusted to the actual viewing range of the receiver, particularly SPAD arrays, depending on the measured distance. In this configuration, the pilot beam spot is no longer adjusted to the size of the transmitted beam spot.

[0044] The variable aperture is particularly advantageous when used in combination with a transmitter that emits light beams at a wide angle. The transmitter is then preferably a VCSEL array. This allows the light beams to cover a large measurement area. The variable aperture can then be used to selectively mark, i.e., visualize, individual sub-areas of the measurement area, for example, the areas within which objects are to be detected.

[0045] According to another advantageous embodiment, a controllable lens is provided by means of which the course of the pilot light rays is adapted to the course of the light rays.

[0046] The lens can be controlled, particularly based on measured distance values, to adjust the size of the pilot light spot to the respective object distance. Specifically, the lens can be controlled so that the size of the pilot light spot corresponds to the size of the main light spot throughout the entire monitoring area.

[0047] According to a further advantageous embodiment, an adjustment mechanism is provided which is designed to change the direction of the pilot light beams.

[0048] The adjustment mechanism is used to predefine the direction of the pilot light beams in an adjustment process during device assembly, so that the coupling means can then couple the pilot light beams into the beam path of the light beams in such a way that the pilot light beams and light beams run coaxially.

[0049] The adjustment mechanism is particularly advantageously implemented by means of a swivel bearing, with which the direction of the pilot light beams can be adjusted in one or two spatial directions.

[0050] It is particularly advantageous if the pilot transmitter unit is arranged on a circuit board which can be swivelled by means of a swivel bearing.

[0051] Generally, fixing devices are available to permanently fix an optimized position, particularly the swivel position of the pilot transmitter unit, found during adjustment. Soldered and adhesive bonds are suitable as fixing devices.

[0052] According to a particularly advantageous embodiment, switching means are provided by means of which the pilot transmitter unit can be switched on and off.

[0053] The pilot transmitter can then be selectively activated only during predefined time periods when visualization of the light beams with the pilot light beams is required. Activation and deactivation of the pilot transmitter can be achieved by inputting control signals into the optical distance sensor or by operating a control element on the optical distance sensor. In particular, the pilot transmitter can remain activated for a preset time after operator-guided activation.

[0054] The functionality of the optical distance sensor can be further enhanced by using the pilot light beams as a display means for showing sensor information.

[0055] The sensor information to be displayed can include status states, especially error states.

[0056] In particular, the optical distance sensor can also be designed in such a way that, depending on the determined distance values, a binary switching signal is generated, the switching states of which indicate whether an object is present within a predefined distance range or not. The switching states of the signal can then be displayed as sensor information.

[0057] Different flashing frequencies of the visible pilot light beams can display several different sensor information.

[0058] Alternatively or additionally, different sensor information can be displayed using different colors of the pilot light beams, whereby different colors of the pilot light beams can be generated by the pilot transmitter unit having several transmitter elements that emit light in different colors.

[0059] For example, the pilot transmitter unit can have two transmitter elements, such as LEDs, which generate pilot light beams of different colors. The coupling means can be used to guide the beams so that the differently colored pilot light beams run parallel to each other. Different sensor information can then be displayed by activating either both transmitter elements or only one of them.

[0060] The invention will be explained below with reference to the drawings. The drawings show: Figure 1: First embodiment of the optical distance sensor according to the invention. Figure 1a: Beam cross-sections of light beams and pilot light beams for the optical distance sensor according to the invention. Figure 1 Figure 2: Further embodiment of the optical distance sensor according to the invention. Figure 3: Further embodiment of the optical distance sensor according to the invention. Figure 4: Further embodiment of the optical distance sensor according to the invention. Figure 5: Further embodiment of beam cross-sections of pilot light beams and light beams. Figures 6a, 6b: Examples of structures of optical deflection elements for the optical distance sensor. Figure 7: Example of a visualization of a partial range of light beams using pilot light beams. Figure 8: Further embodiment of the optical distance sensor according to the invention. Figure 8a: Variant of the embodiment according to Figure 8Figure 9: Beam cross-sections of light beams and pilot light beams for the optical distance sensor according to Figure 8 Figure 10: First example of coupling means in the form of optical fibers for the optical distance sensor according to the invention. Figure 11: Second example of coupling means in the form of optical fibers for the optical distance sensor according to the invention. a) Top view b) Sectional view

[0061] Figure 1 schematically shows components of a first embodiment of the optical distance sensor according to the invention 1.

[0062] With the optical distance sensor 1 according to Figure 1In all the following embodiments, the distance to objects within a monitored area is determined. The distance measurements are performed using a pulse-time-of-flight method. For this purpose, the optical distance sensor 1 generally comprises a light beam 2 emitting transmitter 3 and a light beam 2 receiving receiver 4. The transmitter 3 emits light beams 2 in the non-visible wavelength range. The transmitter 3 emits the light beams 2 in the form of light pulses. The time of flight of the light pulses emitted by the transmitter 3 to an object and back to the receiver 4 is used to determine the distance. The distance determination takes place in an evaluation unit (not shown) depending on the received signals at the output of the receiver 4.

[0063] The optical distance sensor 1 can directly output the distance value via an output not shown. Alternatively, the evaluation unit generates a binary switching signal as an output signal, depending on the determined distance values. The switching states of this signal indicate whether an object is within a predefined monitoring range.

[0064] Transmitter 3 is advantageously formed by an infrared light-emitting diode, in particular a laser diode. Transmitter 3 is particularly advantageously formed by a VCSEL diode.

[0065] The receiver 4 advantageously consists of one or more SPADs (singlephoton avalanche diodes).

[0066] The evaluation unit consists of a processor system, which in the simplest case can be a single processor. Generally, the processor system can also have a multi-channel processor arrangement, especially if the optical distance sensor 1 is a safety sensor.

[0067] How Figure 1 As shown, the transmitter 3 and the receiver 4 are combined in a runtime module 5 forming an integrated component, which is mounted on a circuit board 6.

[0068] To shape the light rays 2 emitted by the transmitter 3, a transmitting optic in the form of a transmitting lens 7 is arranged downstream of the transmitter 3. This results in collimated light rays 2. To focus the light rays 2 reflected back from an object to the optical distance sensor 1, a receiving optic in the form of a receiving lens 8 is arranged upstream of the receiver 4.

[0069] According to the invention, the optical distance sensor 1 (in all embodiments) is provided with a pilot transmitter 9 which emits visible pilot light beams 10. In the present case, the pilot transmitter 9 emits green light. The pilot transmitter 9 can also emit pilot light beams 10 of other colors, in particular red.

[0070] The pilot transmitter unit 9 can, for example, consist of a light-emitting diode arrangement, which can include one or more light-emitting diodes.

[0071] In the embodiment according to Figure 1 The pilot transmitter unit 9 is mounted on the same circuit board 6 on which the runtime module 5 is also mounted.

[0072] An aperture 11 is mounted on the pilot transmitter unit 9, which adjusts the size of the light spot 2a of the pilot light beams 10 to the size of the light spot 2a of the light beams 2. Alternatively, the aperture 11 can be located at a distance from the pilot transmitter unit 9. In this case, a variable aperture 11 can be used, particularly in the form of a TFT matrix.

[0073] According to the invention, coupling means are provided by means of which the pilot light beams 10 are coupled into the beam path of the light beams 2 in such a way that the pilot light beams 10 and light beams 2 run coaxially, preferably within the entire monitoring area. Figure 1a The diagram shows, in a cross-sectional view, the light spot 2a of light rays 2 and the light spot 10a of pilot light rays 10. As shown from Figure 1a These light spots 2a and 10a clearly overlap partially.

[0074] In the present case, a deflecting mirror 12 and a deflecting element 13 in the form of a dichroic mirror are provided as coupling means. The pilot light rays 10 are reflected at the deflecting mirror 12. The dichroic mirror has a wavelength-dependent characteristic and reflects the pilot light rays 10. On the other hand, the dichroic mirror is transparent to the light rays 2.

[0075] These coupling means create a coaxial beam path for light rays 2 and pilot light rays 10, so that the beam path of light rays 2 is visualized with the pilot light rays 10.

[0076] A first lens 14 is located between the pilot transmitter unit 9 and the deflecting mirror 12. A second lens 15 is located between the deflecting mirror 12 and the dichroic mirror.

[0077] The lenses 14, 15 are preferably controllable in order to be able to variably adjust the course of the pilot light beams 10 in the monitoring area.

[0078] Figure 2 Figure 1 shows another embodiment of the optical distance sensor. In contrast to the embodiment according to Figure 2, the following applies: Figure 1 The pilot transmitter 9 is arranged on a further circuit board 16, which is pivotably mounted on the first circuit board 6. By pivoting the circuit board 16 (illustrated by the double arrow I), the direction of the visible pilot light beams 10 emitted by the pilot transmitter 9 can be adjusted.

[0079] A shutter 11 is mounted on the pilot transmitting unit 9. The only coupling means is the dichroic mirror, through which the pilot light beams 10 are coupled in coaxially to the light beams 2.

[0080] Figure 3 shows a variant of the embodiment according to Figure 2The transmitter 3 and the receiver 4 form spatially separate units in this case. The transmitter 3, with the additional circuit board 16 which carries the pilot transmitter unit 9, is located on a first circuit board 6a, and the receiver 4 on a second circuit board 6b.

[0081] The pilot light beams 10 are coupled back into the beam path of the light beams 2 via a dichroic mirror. A lens 15 is located between the pilot transmitter unit 9, possibly with an upstream aperture 11 (not shown), and the dichroic mirror.

[0082] The transmitting lens 7 is located between transmitter 3 and the dichroic mirror.

[0083] Between receiver 4 and receiving optics there is an optical filter 17, with which the pilot light rays 10 and ambient light are blocked, so that only light rays 2 hit the receiver 4.

[0084] Such an optical filter 17 can also be used in the embodiments according to the Figure 1 and 2 to be available.

[0085] Figure 4 shows a variant of the embodiment according to Figure 3 In this case, the transmitting lens 7 is arranged in the beam path of the light rays 2 behind the dichroic mirror and also serves to shape the pilot light rays 10 so that the lens 15 can be omitted.

[0086] Figure 5 shows a variant of transmitter 3 in the form of a VCSEL array that generates multiple light beams 2, where Figure 5 whose light spots 2a are shown in a cross-sectional view. The light spot 10a of the pilot light rays 10 surrounds these light spots 2a. Here too, the light rays 2 and pilot light rays 10 run coaxially. The optical distance sensor 1 can be configured according to the Figure 1 , 2 , 3 or 4 exhibit.

[0087] The Figures 6a, 6bFigure 1 shows exemplary embodiments of deflection elements 13 in the form of geometric beam splitters, which have reflective surfaces 18 on a transparent glass substrate 19. The transparent glass substrate is transparent to the light rays 2. The pilot light rays 10 are reflected at the reflective surfaces 18, whereby specific beam patterns of the pilot light rays 10 can be generated according to the design of the reflective surfaces 18.

[0088] By implementing transmitter 3 as a VCSEL array with specially designed optics, a large opening angle of the light beams 2 can be achieved, as sufficient transmission power is available to ensure that the irradiance on the object is precisely as shown in Figure 7 depicted.

[0089] In this case, a variable aperture 11 in the form of a TFT matrix is ​​connected to the pilot transmitter unit 9. By appropriately controlling the TFT matrix, individual areas 20 of the light beams 2 can be visualized and thus marked, as Figure 7 shows.

[0090] Figure 8 shows an extension of the embodiment according to Figure 1 .

[0091] The embodiment according to Figure 8 differs from the embodiment according to Figure 1This is achieved by the fact that, in addition to the pilot light beam 10 emitting pilot light beams 10, there is another pilot light beam 9' which emits further pilot light beams 10'. A shutter 11' and a lens 14' are also arranged downstream of the further pilot light beam 9'. The pilot light beams 9 and 9' emit pilot light beams 10 and 10' of different colors. In this case, pilot light beam 9 emits green pilot light beams 10, and pilot light beam 9' emits red pilot light beams 10'.

[0092] The pilot light beams 10, 10' of both pilot transmitting units 9, 9' are each deflected via a deflecting mirror 12, 12' and guided to the dichroic mirror.

[0093] Through these coupling means, the pilot light rays 10 run coaxially to the light rays 2 and the further pilot light rays 10' are laterally offset to them, like the corresponding light spots 2a of the light rays 2 and the light spots 10a, 10a' of the pilot light rays 10, 10' according to Figure 9 show.

[0094] Different sensor information can be displayed using the different pilot light beams 10, 10' and their different colors.

[0095] Different sensor information can also be displayed by different flashing frequencies of the pilot light beams 10, 10'.

[0096] Advantageously, the optical distance sensor 1 according to the invention includes switching means by which the pilot transmitter unit 9, 9' can be switched on and off. This allows the pilot transmitter unit 9, 9', or each pilot transmitter unit, to be activated for specific periods of time.

[0097] The switching means can be formed by control signals read into the optical distance sensor 1 or by operating elements on the optical distance sensor 1. The switching means can be used to activate the pilot transmitter unit 9, 9'. The pilot transmitter unit 9, 9' can then remain active for a predefined period. Alternatively, the pilot transmitter unit 9, 9' can be switched off via the switching means.

[0098] Figure 8a shows a variant of the embodiment according to Figure 8 In this case, the pilot light beams 10, 10' are guided together over the deflecting mirror 12, 12'.

[0099] The Figures 10 and 11a, 11b schematically show coupling means in the form of light guides 21 with which the pilot light beams 10, 10' of the pilot transmitting units 9, 9' are coupled into the beam path of the light beams 2, so that the pilot light beams 10, 10' run coaxially to the light beams 2. Reference symbol list

[0100] (1) Optical distance sensor (2) Light beams (2a) Light spot (3) Transmitter (4) Receiver (5) Time-of-flight module (6) Circuit board (6a) First circuit board (6b) Second circuit board (7) Transmitting lens (8) Receiving lens (9, 9') Pilot transmitter unit (10, 10') Pilot light beam (10a) Light spot (11, 11') Aperture (12, 12') Deflection mirror (13) Deflection element (14, 14') First lens (15) Second lens (16) Circuit board (17) Optical filter (18) Area (19) Star support (20) Region (21) Steel support (I) Double arrow

Claims

1. Optical distance sensor (1) with a transmitter (3) that emits light beams (2) in a non-visible wavelength range, and with a receiver (4) which is designed to receive light beams (2) reflected back from an object, and with an evaluation unit which is designed to determine the distance of the object depending on reception signals from the receiver (4), wherein a pilot transmission unit (9, 9') is provided which emits visible pilot light beams (10, 10') are emitted, wherein the pilot light beams (10, 10') are coupled into the beam path of the light beams (2) by means of coupling means in such a way that the pilot light beams (10, 10') and light beams (2) run coaxially with at least partially overlapping beam cross-sections, characterised in that a variable aperture (11, 11') is provided, by means of which the pilot light beams (10, 10') are shaped in such a way that they illuminate part of the light spot (2a) of the light beams (2).

2. Optical distance sensor (1) according to claim 1, characterised in that the transmitter (3) emits light beams (2) in the form of light pulses, and that the distance measurement is carried out according to a pulse transit time method.

3. Optical distance sensor (1) according to one of claims 1 or 2, characterised in that the transmitter (3) is a VCSEL unit.

4. Optical distance sensor (1) according to one of claims 1 to 3, characterised in that the transmitter (3) and the pilot transmission unit (9, 9') are each formed by a semiconductor chip, wherein these are arranged one above the other and wherein the upper semiconductor chip has a hole as a coupling means, wherein light from the other semiconductor chip is guided through this hole, or that a material is applied to a partial surface of the transmitter (3) which converts invisible light into visible light, or that light guides are provided as coupling means.

5. Optical distance sensor (1) according to one of claims 1 to 3, characterised in that an optical deflection element (13) is provided as a coupling means.

6. Optical distance sensor (1) according to claim 5, characterised in that the optical deflection element (13) is a dichroic mirror or forms an interference filter.

7. Optical distance sensor (1) according to one of claims 5 or 6, characterised in that the optical deflection element (13) is used to predetermine the shape of the beam cross-section of the pilot light beams (10, 10').

8. Optical distance sensor (1) according to one of claims 1 to 7, characterised in that the size of the light spot (2a) of the pilot light beams (10, 10') is adjusted to the size of the light spot (2a) of the light beams (2) by means of an aperture (11, 11').

9. Optical distance sensor (1) according to one of claims 1 to 8, characterised in that a controllable lens (14, 14') is provided, by means of which the path of the pilot light beams (10, 10') is adjusted to the path of the light beams (2).

10. Optical distance sensor (1) according to one of claims 1 to 9, characterised in that an adjustment mechanism is provided which is designed to change the beam direction of the pilot light beams (10, 10').

11. Optical distance sensor (1) according to one of claims 1 to 10, characterised in that switching means are provided by means of which the pilot transmission unit (9, 9') can be switched on and off.

12. Optical distance sensor (1) according to one of claims 1 to 11, characterised in that the pilot light beams (10, 10') form a display means for displaying sensor information.

13. Optical distance sensor (1) according to claim 12, characterised in that different sensor information is displayed by different colours and / or different flashing frequencies of the pilot light beams (10, 10').

14. Optical distance sensor (1) according to one of claims 1 to 13, characterised in that different colours of the pilot light beams (10, 10') are generated by the pilot transmitting unit (9, 9') having several transmitting elements that emit light in different colours.