Measurement device, light receiver, and light projector

Abstract

A measurement device (100) is provided with a light projector and a light receiver that receives reflected light generated by projecting light toward a field of view by the light projector. The light receiver is provided with a light receiving unit (16) and a transmission-type diffraction grating (151). The diffraction grating (151) is disposed such that first reflected light from a first field of view (51a) is incident on the light receiving unit (16) as diffracted light of a first order, and second reflected light from a second field of view (51b) parallel to the first field of view (51a) is incident on the light receiving unit (16) as diffracted light of a second order.

Description

Technical Field

[0001] The present disclosure relates to a measuring device, a light receiver, and a light projector, and in particular to a technology for extending the field of view of the measuring device. Background Art

[0002] With the development of AD (Autonomous Driving) and ADAS (Advanced Driver Assistance System), LiDAR (Light Detection and Ranging) is being developed and researched as one of the measuring devices used to grasp the surrounding environment and estimate the vehicle's own position when the vehicle is driving. LiDAR has a projector that projects (irradiates) laser light to the measured object and a receiver that receives the reflected light returned by the laser reflected by the measured object. LiDAR measures the distance to the measured object based on the difference between the timing of the projector emitting laser light and the timing of the receiver receiving the reflected light, thereby providing information related to the measured object.

[0003] Patent document 1 describes a LiDAR system configured for installation on a vehicle. The LiDAR system includes a plurality of light emitters (VCSEL (Vertical Cavity Surface Emitting Laser) devices, etc.) that generate light beams. The LiDAR system converges the plurality of light beams into a converged light beam having a beam waist through a first lens, and projects the converged light beam to a target range through a second lens.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Application No. 2020-527724 Summary of the invention

[0007] Technical problem to be solved by the invention

[0008] One type of LiDAR is Flash LiDAR, which uses a projector to diffuse laser light within the field of view. Flash LiDAR does not include mechanical structures such as motors and MEMS (Micro Electro Mechanical Systems), so it has attracted attention as a strong candidate for LiDAR in fields that require durability, such as when used for vehicle-mounted purposes.

[0009] The field of view (FOV (Field Of View): field of view angle, beam profile, light distribution size) of the light receiver and light emitter of the flash LiDAR is determined by the size (area) of the light receiving part and the light emitting part and the focal length of the optical system (light receiving optical system, light projecting optical system). Therefore, when applying the flash LiDAR to various systems such as ranging sensors for vehicles, it is necessary to configure the field of view to meet the specifications required by the system to which it is applied.

[0010] As a method of expanding the field of view of the vehicle-mounted LiDAR, for example, multiple LiDARs may be arranged side by side. However, in this case, the increase in the number of components and the cost becomes a technical problem. In addition, for example, it is necessary to be able to flexibly respond to the need to improve the measurement accuracy of a specific field of view (light projection range, field of view range) (for example, to improve the long-distance visual recognition of the driving direction during driving).

[0011] The present disclosure has been made in view of such a background, and an object of the present disclosure is to provide a measuring device, a light projector, and a light receiver that can flexibly cope with the specifications required by a system of an application target.

[0012] Technical solutions for solving technical problems

[0013] One embodiment of the present disclosure is a measuring device, wherein the measuring device includes a light projector and a light receiver that receives reflected light generated by the light projector projecting light toward a field of view, the light receiver includes a light receiving portion and a transmission-type diffraction grating, and the diffraction grating is configured so that first reflected light from a first field of view is incident on the light receiving portion as first-order diffracted light, and second reflected light from a second field of view parallel to the first field of view is incident on the light receiving portion as second-order diffracted light.

[0014] Another embodiment of the present disclosure is a measuring device, wherein the measuring device includes a projector and a light receiver that receives reflected light generated by the light projector projecting light toward a field of view, the projector includes a light-emitting unit and a transmission-type diffraction grating, the diffraction grating being configured to emit a first order of diffracted light generated by light from the light-emitting unit passing through the diffraction grating toward a first field of view, and to emit a second order of diffracted light generated by light passing through the diffraction grating toward a second field of view parallel to the first field of view.

[0015] Another embodiment of the present disclosure is a measuring device, wherein the measuring device includes a light projector and a light receiver that receives reflected light generated by the light projector projecting light toward a field of view, the light receiver includes a light receiving portion and a transmission-type optical element, the optical element having: a first incident surface, the first incident surface for incident first reflected light from a first field of view; a second incident surface, the second incident surface is formed continuously with the first incident surface, and is for incident second reflected light from a second field of view continuous with the first field of view; an exit surface, the exit surface causes the first reflected light and the second reflected light to exit toward the light receiving portion; the first incident surface, the second incident surface, and the exit surface are all flat surfaces, and the second incident surface is inclined relative to the first incident surface with the boundary line with the first incident surface as a fold.

[0016] Another embodiment of the present disclosure is a measuring device, wherein the measuring device includes a light projector and a light receiver that receives reflected light generated by the light projector projecting light toward a field of view, the light projector includes a light-emitting unit and a transmission-type optical element, the optical element having: an incident surface, the incident surface for light from the light-emitting unit to be incident; a first exit surface, the first exit surface emits the light incident on the incident surface toward a first field of view; and a second exit surface, the second exit surface emits the light incident on the incident surface toward a second field of view, the incident surface, the first exit surface, and the second exit surface are all flat surfaces, and the second exit surface is inclined relative to the first exit surface with the boundary line with the second exit surface as a fold.

[0017] In addition, the technical problems disclosed in the present application and solutions thereto are clarified through the section of detailed description and the accompanying drawings.

[0018] Effects of the Invention

[0019] According to the present disclosure, it is possible to provide a measuring device, a light projector, and a light receiver that can flexibly cope with the specifications required by a system of an application target. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a diagram showing a schematic structure of a measuring device.

[0021] Figure 2A This is a diagram for explaining the relationship between the light receiving unit, the light receiving optical system, and the field of view.

[0022] Figure 2B This is a diagram for explaining the relationship between the light emitting unit, the light projection optical system, and the field of view.

[0023] Figure 3 This is a diagram for explaining the relationship between the light receiver and the field of view when a diffraction grating is used in the light receiving optical system according to the first embodiment.

[0024] Figure 4A This is a diagram for explaining one aspect of the structure of a measuring device for distinguishing from which field of view range the reflected light comes.

[0025] Figure 4B This is a diagram showing one embodiment of the arrangement of the diffraction grating.

[0026] Figure 5A Yes means Figure 4A A diagram showing the relationship between the field of view and the light-receiving image in the structure shown.

[0027] Figure 5B This is a diagram showing the relationship between the field of view range and the light-receiving image when the arrangement direction of the slits of the diffraction grating is not rotated around the optical axis.

[0028] Figure 6 This is a diagram for explaining parameters that determine the characteristics of the diffraction grating.

[0029] Figure 7 This is a diagram for explaining the relationship between the light projector and the field of view when a diffraction grating is used in the light projection optical system according to the second embodiment.

[0030] Figure 8 It is a diagram for explaining the relationship between the light receiver and the field of view according to the third embodiment.

[0031] Fig. 9A Is applied to Figure 8 A three-dimensional diagram of the appearance of the optical components of the light receiver.

[0032] Fig. 9B Is applied to Figure 8 Side view of the optical components of the light receptor.

[0033] Fig. 10A This is a diagram for explaining one aspect of the structure of a measuring device for distinguishing from which field of view range the reflected light comes.

[0034] Fig. 10B is Fig. 10A A perspective view of the appearance of the optical components used in the structure.

[0035] Fig.11 It is a diagram for explaining the relationship between the light projector and the field of view according to the fourth embodiment.

[0036] Fig. 12A Is applied to Fig.11 A three-dimensional diagram of the appearance of the optical components of the projector.

[0037] Fig. 12B Is applied to Fig.11 Side view of the optical components of the light projector. DETAILED DESCRIPTION

[0038] Hereinafter, the method for implementing the present disclosure will be described with reference to the accompanying drawings. In addition, in the following description, the same or similar structures are sometimes marked with the same reference numerals and repeated descriptions are omitted. In addition, in the following description, when it is necessary to distinguish the same structure, an identifier (such as a letter) is sometimes added after the reference numeral of the general structure.

[0039] Figure 1 The schematic structure (block diagram) of the measuring device 100 is shown as one embodiment of the present disclosure. The measuring device 100 includes a projector that projects (irradiates) a projection light (irradiation light, light beam (laser)) to a measuring object and a light receiver that receives reflected light (return light) that is reflected by the measuring object and returns, and functions as a flash LiDAR (Flash Light Detection and Ranging). The measuring device 100 measures the difference between the timing of the projector emitting the projection light and the timing of the light receiver receiving the reflected light (the flight time of the laser, hereinafter referred to as "TOF" (Time Of Flight)), and obtains information related to the measuring object.

[0040] The measuring device 100 is mounted on a vehicle equipped with an AD (Autonomous Driving) or an ADAS (Advanced Driver Assistance System). The measuring device 100 assists in detecting a person, another vehicle, or an object while the vehicle is driving, and provides various useful information to other devices or users, thereby ensuring the safety of the driver of the vehicle or people around the vehicle and reducing damage to surrounding objects during vehicle driving.

[0041] As shown in the figure, the exemplary measuring device 100 includes a light emitting unit 11, a light projection control device 112, a current source 113, a light projection optical system 14, a light receiving optical system 15, a light receiving unit 16, a TOF measuring device 117, a computing device 150, and a communication I / F 160 (I / F: Interface). The light emitting unit 11, the light projection control device 112, the current source 113, and the light projection optical system 14 constitute a light projector, and the light receiving optical system 15 and the light receiving unit 16 constitute a light receiver.

[0042] The light-emitting unit 11 constituting the light projector is constructed using one or more light-emitting elements or one or more light-emitting element arrays (for example, the light-emitting elements are arranged linearly (one-dimensionally) or planarly (two-dimensionally)). The light-emitting element is, for example, a laser diode, a surface-emitting laser light-emitting element (for example, VCSEL (Vertical Cavity Surface Emitting Laser: vertical cavity surface emitting laser). hereinafter referred to as a "surface-emitting element")), a surface-emitting element array (for example, a VCSEL array) in which a plurality of surface-emitting elements are arranged one-dimensionally or two-dimensionally on a substrate (a semiconductor substrate, a ceramic substrate, etc.).

[0043] The light projection control device 112 controls the current (driving current) supplied from the current source 113 to the light emitting element by generating a control signal of the current source 113 for supplying the driving current to the light emitting element constituting the light emitting unit 11 and inputting the control signal to the current source 113. The light projection control device 112 inputs a signal indicating the timing of light emission of the light emitting element (the timing of the projection light being emitted from the light emitting element, hereinafter referred to as "light projection timing") to the TOF measuring device 117. The light projection control device 112 controls the current flowing through each light emitting element to be periodically and repeatedly turned on and off, for example, so that the light emitting element periodically and repeatedly emits light.

[0044] The current source 113 supplies the light emitting elements with a current corresponding to a control signal input from the light projection control device 112. For example, the current source 113 supplies the light emitting elements with a periodic square wave current for turning on and off the current flowing through each light emitting element.

[0045] The light projection optical system 14 adjusts the light distribution of the projection light by applying an optical effect (refraction, scattering, diffraction, etc.) to the projection light emitted from the light emitting unit 11. The light projection optical system 14 is configured using optical components such as various lenses such as a collimator lens and a mirror.

[0046] The light receiving optical system 15 collects the reflected light (return light) projected by the light projector and reflected by the measuring object 50 and the like, and collects it on the light receiving unit 16. The light receiving optical system 15 is configured using optical components such as various lenses such as a condenser lens, various filters such as a wavelength filter, and a mirror.

[0047] The light receiving unit 16 is composed of one or more light receiving elements (a plurality of light receiving elements) or one or more light receiving element arrays (for example, the light receiving elements are arranged linearly (one-dimensionally) or planarly (two-dimensionally)). The light receiving element is, for example, a photodiode, a SPAD (Single Photon Avalanche Diode), a balanced photodetector, etc. The light receiving unit 16 generates a current (hereinafter referred to as "light receiving current") corresponding to the intensity of the reflected light by performing photoelectric conversion on the reflected light incident from the light receiving optical system 15. The light receiving unit 16 inputs a signal indicating the timing of receiving the reflected light (hereinafter referred to as "light receiving timing") of each light receiving element constituting the light receiving unit 16 and the light receiving current generated by each light receiving element to the TOF measuring device 117.

[0048] The TOF measuring device 117 obtains TOF based on the signal indicating the light projection timing input from the light projection control device 112 and the signal indicating the light reception timing input from the light receiving unit 16. The TOF measuring device 117 is configured using, for example, a time measurement IC (Integrated Circuit) equipped with a TDC (Time to Digital Converter) circuit. The TOF measuring device 117 inputs the obtained TOF and the light reception current input from the light receiving unit 16 to the computing device 150.

[0049] The computing device 150 is composed of a processor (CPU (Central Processing Unit), MPU (Micro Processing Unit), ASIC (Application Specific Integrated Circuit), FPGA (Field Programmable Gate Array), DSP (Digital Signal Processor), etc.). The computing device 150 generates various measurement information such as detection and distance measurement of the measuring object 50 based on the photoreceiving current and TOF input from the TOF measuring device 117. The above information is, for example, a histogram used in the time-correlated single photon counting method, a distance to each point of the measuring object 50, a point cloud (point group information: point cloud), etc. In addition, the computing device 150 controls the light projection control device 112 and the light receiving unit 16. The computing device 150 controls the above-mentioned light projection timing and light reception timing, for example, by controlling the light projection control device 112 and the light receiving unit 16, so as to speed up or optimize the processing involved in the generation of the histogram. The information generated by the computing device 150 is provided (sent) to the device that uses the information (hereinafter referred to as "various using devices 40") via the communication I / F 160.

[0050] Various utilization devices 40 perform, for example, the creation of an environment map based on a point cloud, self-position estimation (SLAM (Simultaneous Localization and Mapping)) using a scan matching algorithm (NDT (Normal Distributions Transform), ICP (Iterative Closest Point), etc.), and the like.

[0051] Figure 2A Schematic diagram for explaining the relationship between the light receiving unit 16 and the light receiving optical system 15 and the field of view 51 . The field of view 51 is determined by the size (shape, size, light receiving area) of the light receiving region of the light receiving unit 16 and the focal length of the light receiving optical system 15 .

[0052] Figure 2B Schematic diagram for explaining the relationship between the light emitting unit 11 and the light projection optical system 14 and the field of view 51. The field of view 51 is determined by the size (shape, size, light receiving area) of the light emitting region of the light emitting unit 11 and the focal length of the light projection optical system 14.

[0053] Thus, the size of the field of view 51 is limited by the size of the light receiving unit 16 and the size of the light emitting unit 11. Therefore, the field of view when using existing products as the light receiving unit 16 and the light emitting unit 11, for example, does not necessarily match the purpose and use of the system to which the measuring device 100 is applied. In addition, depending on the purpose and use of the measuring device 100, there is a demand to make the measurement accuracy of a specific field of view higher than that of other field of view. For example, when flash LiDAR is applied to AD or ADAS, there is a demand to improve the measurement accuracy of a specific field of view such as the far side of the oncoming lane. It is necessary to flexibly respond to such demands.

[0054] Therefore, in the measuring device 100 of the present embodiment, the above-mentioned demand is met by using a diffraction grating (diffractive optical element) as an element of the light receiving optical system 15 of the light receiver or the light projecting optical system 14 of the light projector.

[0055] <First Embodiment: Case of Using a Diffraction Grating in a Light Receiving Optical System>

[0056] Figure 3 This is a diagram for explaining the relationship between a light receiver and a field of view 51 of the light receiver (a first field of view 51a, a second field of view 51b, and a third field of view 51c arranged in the +x direction in the figure) when a diffraction grating (diffraction optical element) is used in the light receiving optical system 15 of the light receiver. The figure depicts the elements of the light receiver (the light receiving optical system 15, the light receiving unit 16) as a diagram of them observed from a direction perpendicular to the optical axis of the light receiving unit 16 (a diagram observed from the +y side). In addition, the figure depicts the field of view 51 as a diagram observed from the direction of the above-mentioned optical axis (a diagram observed from the -z side). The arrows shown in the figure represent reflected light that is incident on the light receiver from each field of view and is generated by projecting light toward each field of view 51 (the first field of view 51a, the second field of view 51b, and the third field of view 51c) by a light projector. The figure exaggerates the size of the light receiver.

[0057] As shown in the figure, the light receiving optical system 15 includes a diffraction grating 151 having periodic microscopic projections and depressions of wavelength order formed on the surface, and other optical systems 152 (various lenses, various filters, etc.) In the present embodiment, the diffraction grating 151 is a transmission type phase grating.

[0058] As shown in the figure, the reflected light (hereinafter referred to as "first reflected light") incident on the diffraction grating 151 from the first field of view 51a enters the other optical system 152 as +1-order diffracted light (first-order diffracted light). The reflected light (hereinafter referred to as "second reflected light") incident on the diffraction grating 151 from the second field of view 51b adjacent to the first field of view 51a enters the other optical system 152 as 0-order diffracted light (second-order diffracted light). The reflected light (hereinafter referred to as "third reflected light") incident on the diffraction grating 151 from the third field of view 51c adjacent to the second field of view 51b enters the other optical system 152 as -1-order diffracted light (third-order diffracted light). In addition, each reflected light (first reflected light, second reflected light, third reflected light) incident on the other optical system 152 is focused on the light receiving unit 16.

[0059] In this way, by using the diffraction grating 151 as an element of the light receiving optical system 15, the reflected light from each field of view 51 (the first field of view 51a, the second field of view 51b, and the third field of view 51c) can be focused on the light receiving unit 16. Therefore, the field of view (FOV) of the light receiver can be expanded without increasing the light receiving area of ​​the light receiving unit 16 (without increasing the number of light receiving elements).

[0060] In addition, as shown in the figure, in this structure, the reflected light (diffracted light) from each field of view 51 (the first field of view 51a, the second field of view 51b, and the third field of view 51c) is incident on the same light receiving element of the light receiving unit 16. Therefore, when installing it in the measurement device 100, a certain mechanism is required to distinguish which field of view 51 the reflected light is received from.

[0061] The above mechanism can be realized, for example, by making the light from the projector to each field of view 51 (the first field of view 51a, the second field of view 51b, and the third field of view 51c) be projected at different timings for each field of view 51. In this case, for example, the computing device 150 controls the light projection control device 112 so that the light from the projector is projected at different timings for each field of view 51, and distinguishes which field of view 51 the reflected light comes from based on the timing at which the light receiving element of the light receiving unit 16 receives the reflected light (hereinafter referred to as the "first method").

[0062] In addition, for example, in order to prevent the reflected light (+1-order diffracted light, 0-order diffracted light, -1-order diffracted light) from each of the first field of view 51a, the second field of view 51b, and the third field of view 51c from entering the same light receiving element of the light receiving unit 16, the light projector may select a portion of each field of view 51 (a portion of the first field of view 51a, a portion of the second field of view 51b, and a portion of the third field of view 51c so as not to enter the same light receiving element), and simultaneously project light onto each selected region (hereinafter referred to as the "second method"). According to the second method, since the regions of each of the above-mentioned field of view 51 can be simultaneously received, the time (scanning speed) required for projecting light onto all of the field of view 51 (the first field of view 51a, the second field of view 51b, and the third field of view 51c) can be shortened.

[0063] In addition, for example, Figure 4A As shown in FIG. 1 , the light projector simultaneously projects light on a strip area 55 spanning the first viewing range 51a, the second viewing range 51b, and the third viewing range 51c. Figure 4B As shown, the diffraction grating 151 may be configured as a slit 1511 (a unit of a grating composed of convex portions and concave portions ( Figure 6 )) is arranged in a direction relative to the extension direction of the above-mentioned band-shaped region 55 around the optical axis of the diffraction grating 151 (in Figure 4B The positional relationship is a rotation of a predetermined angle α (hereinafter referred to as the “third method”).

[0064] In this case, the thickness of the above-mentioned strip area 55 (the distance (width) in the y direction in the figure) is set to be shorter than the offset width with the adjacent field of view range 51 (the offset amount (step) in the y direction of the adjacent field of view range 51 in the example in the figure) so that the reflected light from different field of view ranges 51 will not be incident on the light receiving part 16 at the same time.

[0065] Figure 5A This is an example of an image (light receiving image) of the field of view 51 and the reflected light focused on the light receiving unit 16 when the third method is used. As shown in the figure, the reflected light (+1st order diffracted light, 0th order diffracted light, -1st order diffracted light) from each field of view 51 is focused on different light receiving elements of the light receiving unit 16.

[0066] Incidentally, for example, when the optical axis of the diffraction grating 151 is aligned with the extending direction of the band-shaped region 55, as shown in FIG. Figure 5B As shown, reflected light from each viewing range 51 (reflected light from the strip-shaped area 55 of each viewing range 51 ) is simultaneously overlapped and converged on the same light receiving element of the light receiving unit 16 .

[0067] According to the third method described above, light can be projected and received simultaneously on the strip-shaped area 55 from the first viewing range 51 a to the third viewing range 51 c , and the time (scanning speed) required for light projection in the entire viewing range 51 can be shortened.

[0068] As described above, by using the diffraction grating 151 as an element of the light receiving optical system 15, the field of view (FOV) of the light receiver can be easily expanded to the range from the first field of view 51a to the third field of view 51c without expanding the light receiving area of ​​the light receiving unit 16 (without increasing the number of light receiving elements).

[0069] However, the following relationship exists among the angle θ between the incident light and the diffracted light incident on the diffraction grating 151 , the grating pitch d (grating interval), the wavelength λ of the incident light, and the diffraction order M.

[0070] [Number 1]

[0071] M×λ=d×sinθ Formula 1

[0072] Therefore, by selecting the grating pitch d and the wavelength λ of the incident light, the field of view (FOV) of the light receiver can be adjusted. For example, when the wavelength λ of the incident reflected light is 905nm, in order to make the diffraction angle θ of the diffraction grating 151 40° (making the field of view angle of the first field of view 51a +20° to +60°, making the field of view angle of the second field of view 51b ±20°, and making the field of view angle of the third field of view 51c -20° to -60°), the grating pitch d can be set to 1.4μm.

[0073] Figure 6 1 is a diagram for explaining the parameters that determine the characteristics of the diffraction grating 151. The diffraction efficiency (transmittance) of the diffraction grating 151 is determined by the grating density (the proportion of the convex portion 1511a in the slit 1511) and the height of the convex portion 1511a shown in the figure. Therefore, by adjusting these values, the diffraction efficiency (the amount of reflected light incident on the light receiving unit 16) of each reflected light (+1st order diffracted light, 0th order diffracted light, -1st order diffracted light) from each viewing range 51 (first viewing range 51a, second viewing range 51b, third viewing range 51c) can be adjusted.

[0074] For example, in the diffraction grating 151 with a diffraction angle of 40° formed using a material (synthetic quartz, acrylic, etc.) with a refractive index of 1.5, when the height of the convex portion 1511a is 0.724μm and the grating density is 0.2, the light amount of the diffracted light is 21.8% of the +1st order diffracted light, 50% of the 0th order diffracted light, and 21.7% of the -1st order diffracted light when the light amount of the incident light is 100%. In addition, in the diffraction grating 151 with the same material and diffraction angle, when the height of the convex portion 1511a is 0.905μm and the grating density is 0.65, when the light amount of the incident light is 100%, the light amount of the +1st order diffracted light is 31.1%, the light amount of the 0th order diffracted light is 33.1%, and the light amount of the -1st order diffracted light is 31.3%.

[0075] In this way, by selecting the grating pitch d of the diffraction grating 151 and the wavelength λ of the incident light, the field of view 51 (light receiving range) of the light receiver can be adjusted to the field of view required by the system of the application object. In addition, by adjusting the values ​​of parameters such as the refractive index, grating density, and height of the convex portion 1511a of the diffraction grating 151, the diffraction efficiency (light quantity) of each diffracted light (+1st order diffracted light, 0th order diffracted light, -1st order diffracted light) emitted from the diffraction grating 151 can be adjusted. Therefore, for example, it is possible to meet the needs of improving the long-distance visual recognition of the driving direction during driving, and the need to improve the measurement accuracy of a specific field of view. In this way, according to the measurement device 100 of this embodiment, it is possible to flexibly meet the specifications required by the system of the application object.

[0076] <Second Embodiment: Case of Using Diffraction Grating in Light Projection Optical System>

[0077] Figure 7 This is a diagram for explaining the relationship between the projector and the field of view 51 (light projection range) (first field of view 51a, second field of view 51b, third field of view 51c) of the projector when the diffraction grating 141 having the same structure as the diffraction grating 151 used in the above-mentioned light receiving optical system 15 is used in the light projection optical system 14 of the light projector of the measuring device 100. This figure depicts the elements of the projector (the light projection optical system 14 and the light emitting unit 11) as a diagram observed from a direction perpendicular to the optical axis of the light emitting unit 11 (a diagram observed from the +y side). In addition, this figure depicts each field of view 51 as a diagram observed from the direction of the above-mentioned optical axis (a diagram observed from the -z side). The arrows shown in this figure indicate the correspondence between each diffracted light emitted from the projector and each field of view 51 (first field of view 51a, second field of view 51b, third field of view 51c). This figure exaggerates the size of the projector.

[0078] The light projection optical system 14 includes a diffraction grating 141 and other optical systems 142 (various lenses, various filters, etc.). As shown in the figure, the light emitted from the light emitting unit 11 is incident on the diffraction grating 141 through the other optical system 142, and thus, the +1st order diffracted light toward the first field of view 51a, the 0th order diffracted light toward the second field of view 51b, and the -1st order diffracted light toward the third field of view 51c are emitted from the diffraction grating 141.

[0079] In this way, by using the diffraction grating 141 as an element of the light projection optical system 14, the field of view (FOV) of the projector can be easily expanded to the range from the first field of view 51a to the third field of view 51c without expanding the light emitting area of ​​the light emitting unit 11 (without increasing the number of light emitting elements).

[0080] In addition, similarly to the case where the diffraction grating 151 is used in the light receiver, the field of view 51 of the light projector can be adjusted by selecting the grating pitch d of the diffraction grating 141 and the wavelength λ of the incident light. In addition, the diffraction efficiency (light quantity) of each diffracted light (+1st order diffracted light, 0th order diffracted light, -1st order diffracted light) can be adjusted by adjusting the values ​​of parameters such as the refractive index, grating density, and height of the convex portion of the diffraction grating 141. Therefore, it is possible to flexibly cope with the specifications required by the system to which the measuring device 100 is applied.

[0081] The first embodiment uses a diffraction grating (diffraction optical element) as an element of the light receiving optical system 15 of the light receiver. The second embodiment uses a diffraction grating (diffraction optical element) as an element of the light projection optical system 14 of the light projector. In the measurement device 100B of the third embodiment described below, the above-mentioned needs are met by using an optical element having a prism structure as an element of the light receiving optical system 15B of the light receiver or the light projection optical system 14B of the light projector. The specific structure is described below.

[0082] <Third Embodiment: When an Optical Element is Used in a Light Receiving Optical System>

[0083] Figure 8 This is a diagram for explaining the relationship between the light receiver and the field of view 51 of the light receiver (the first field of view 51a, the second field of view 51b, and the third field of view 51c arranged in the +x direction in the figure) when the optical element 151B having a prism structure is used in the light receiving optical system 15B of the light receiver. Figure 8 In the structure shown, Figure 3 The same structures as shown are denoted by the same reference numerals, and their description is omitted.

[0084] As shown in the figure, the light receiving optical system 15B includes an optical element 151B having a prism structure and other optical systems 152 (various lenses, various filters, etc.).

[0085] Fig. 9A The figure shows a three-dimensional view of the appearance of the optical element 151B. As shown in the figure, the optical element 151B has a first incident surface 151a, a second incident surface 151b, and a third incident surface 151c. The first incident surface 151a is formed on the upper surface side of the optical element 151B (the +z side in the figure), and the first reflected light from the first field of view 51a is incident on the first incident surface 151a. The second incident surface 151b is formed continuously with the first incident surface 151a, and the second reflected light from the second field of view 51b continuous with the first field of view 51a is incident on the second incident surface 151b. The third incident surface 151c is formed continuously with the second incident surface 151b, and the third reflected light from the third field of view 51c continuous with the second field of view 51b is incident on the third incident surface 151c. The optical element 151B has an exit surface 151o on the lower surface side (-z side in the figure) of the optical element 151B for emitting the refracted light of the first reflected light, the transmitted light of the second reflected light, and the refracted light of the third reflected light to the light receiving unit 16. The first incident surface 151a, the second incident surface 151b, the third incident surface 151c, and the exit surface 151o are all flat surfaces.

[0086] Fig. 9B is from Fig. 9A A side view of the optical element 151B observed from the +y side. The second incident surface 151b is parallel to the exit surface 151o. The first incident surface 151a is inclined toward the +z side at an inclination angle θ1 relative to the second incident surface 151b with the first boundary line 1511B with the second incident surface 151b as a fold, thereby forming a prism structure on one end side (-x side) of the optical element 151B. In addition, the third incident surface 151c is inclined toward the +z side at an inclination angle θ2 relative to the second incident surface 151b with the second boundary line 1512 with the second incident surface 151b as a fold, thereby forming a prism structure on the other end side (+x side) of the optical element 151B.

[0087] Back to Figure 8 The optical element 151B is arranged so that the optical axis of the optical element 151B (a line passing through the center line of the second incident surface 151b and perpendicular to the exit surface 151o (the normal line of the exit surface 151o)) is Fig. 9B The axis indicated by reference numeral 1515 in the figure is consistent with the optical axis of other optical systems 152 and the light receiving unit 16.

[0088] As shown in the figure, the first reflected light from the first field of view 51a is incident on the first incident surface 151a of the optical element 151B and refracted, then emitted from the emission surface 151o and passes through the other optical system 152, and converges to the light receiving unit 16. The second reflected light from the second field of view 51b is incident on the second incident surface 151b of the optical element 151B, then emitted from the emission surface 151o, and converges to the light receiving unit 16 through the other optical system 152. The third reflected light from the third field of view 51c is incident on the third incident surface 151c of the optical element 151B and refracted, then emitted from the emission surface 151o and passes through the other optical system 152, and converges to the light receiving unit 16.

[0089] In this way, by using the optical element 151B as an element of the light receiving optical system 15B, the reflected light from each field of view 51 (the first field of view 51a, the second field of view 51b, and the third field of view 51c) can be focused on the light receiving unit 16. Therefore, the field of view (FOV) of the light receiver can be expanded without increasing the light receiving area of ​​the light receiving unit 16 (without increasing the number of light receiving elements).

[0090] In addition, as shown in the figure, in this structure, the reflected light from each viewing range 51 (the first viewing range 51a, the second viewing range 51b, and the third viewing range 51c) is incident on the same light receiving element of the light receiving unit 16. Therefore, when installing it in the measurement device 100B, a certain mechanism is required to distinguish which viewing range 51 the reflected light is received from.

[0091] The above mechanism may also use the above-mentioned first method and second method, for example.

[0092] In addition, for example, Fig. 10A As shown in FIG. 1 , the light projector simultaneously projects light onto a strip-shaped area 55 spanning the first visual field 51a, the second visual field 51b, and the third visual field 51c. Fig. 10B As shown in FIG. 1 , the first incident surface 151a is further inclined relative to the second incident surface 151b along the first boundary line 1511B at an inclination angle φ1. Fig. 10B As shown, the third incident surface 151c is further inclined relative to the second incident surface 151b along the second boundary line 1512 in the direction opposite to the first incident surface 151a at an inclination angle φ2 (hereinafter referred to as the "fourth method").

[0093] In this case, the first incident surface 151a can be tilted by rotating around an axis 1516a set in the plane of the first incident surface 151a and parallel to the x-axis, or by rotating around an axis 1517a extending in the same direction as the x-axis. Similarly, the third incident surface 151c can be tilted by rotating around an axis 1516b set in the plane of the third incident surface 151c and parallel to the x-axis, or by rotating around an axis 1517b extending in the same direction as the x-axis.

[0094] Receiver Fig. 10A as well as Fig. 10B In the case of the structure shown in FIG. 1 , an example of the field of view 51 and an image (light receiving image) of the reflected light focused on the light receiving unit 16 is shown in FIG. Figure 5A As shown in the figure, the reflected light from each field of view range 51 is focused on different light receiving elements of the light receiving unit 16 .

[0095] Also, by the way, when using Fig. 9A When the structure shown in the figure is used as the optical element 151B to perform the same light projection (simultaneously projecting light to the strip area 55 from the first field of view 51a to the third field of view), as shown in FIG. Figure 5B As shown, reflected light from each viewing range 51 (reflected light from the strip-shaped area 55 of each viewing range 51 ) is simultaneously overlapped and converged on the same light receiving element of the light receiving unit 16 .

[0096] According to the fourth method described above, light can be projected and received simultaneously on the strip area 55 from the first viewing range 51 a to the third viewing range 51 c , and the time (scanning speed) required for light projection in the entire viewing range 51 can be shortened.

[0097] As described above, by using the optical element 151B having a simple structure as an element of the light receiving optical system 15B, the field of view (FOV) of the light receiver can be easily expanded to the range from the first field of view 51a to the third field of view 51c without expanding the light receiving area of ​​the light receiving unit 16 (without increasing the number of light receiving elements). In addition, by adjusting the tilt angles θ1, θ2 and the tilt angles φ1, φ2, the light receiving range (the first field of view 51a, the third field of view 51c) can be adjusted, and the specifications required by the system of the application object can be flexibly responded to.

[0098] <Fourth Embodiment: Case of Using Optical Element in Light Projection Optical System>

[0099] Fig.11This is a diagram for explaining the relationship between the light projector and the field of view 51 (light projection range) of the light projector (first field of view range 51a, second field of view range 51b, third field of view range 51c) when an optical element 141B having the same structure as the above-mentioned optical element 151B is used in the light projection optical system 14B of the light projector of the measuring device 100B. Fig.11 In the structure shown, Figure 7 The same configurations are denoted by the same reference numerals, and their description is omitted. The arrows shown in the figure indicate the correspondence between the light emitted from the optical element 141B and the respective viewing ranges 51 (the first viewing range 51 a , the second viewing range 51 b , and the third viewing range 51 c ).

[0100] As shown in the figure, the light projection optical system 14B includes an optical element 141B having a prism structure and other optical systems 142 (various lenses, various filters, etc.).

[0101] Fig. 12A The figure shows a perspective view of the appearance of the optical element 141B. As shown in the figure, the optical element 141B has an incident surface 141i on the lower surface side (-z side in the figure) of the optical element 141B, into which the light from the light emitting unit 11 is incident. In addition, the optical element 141B has a first exit surface 141a, a second exit surface 141b, and a third exit surface 141c. The first exit surface 141a is on the upper surface side (+z side in the figure) of the optical element 141B, and emits the light incident on the incident surface 141i from the light emitting unit 11 toward the first field of view 51a. The second exit surface 141b is formed continuously with the first exit surface 141a, and emits the light incident on the incident surface 141i from the light emitting unit 11 toward the second field of view 51b. The third exit surface 141c is formed continuously with the second exit surface 141b, and emits the light incident on the incident surface 141i from the light emitting unit 11 toward the third field of view 51c. The incident surface 141i, the first emission surface 141a, the second emission surface 141b, and the third emission surface 141c are all flat surfaces.

[0102] Fig. 12B is from Fig. 9A Side view of the optical element 141B observed from the -y side. The incident surface 141i is parallel to the second exit surface 141b. The first exit surface 141a is inclined toward the +z side at an inclination angle θ1 relative to the second exit surface 141b, with the first boundary line 1411 with the second exit surface 141b as a fold, thereby forming a prism structure on one end side (-x side) of the optical element 141B. The third exit surface 141c is inclined toward the +z side at an inclination angle θ2 relative to the second exit surface 141b, with the second boundary line 1412 with the second exit surface 141b as a fold, thereby forming a prism structure on the other end side (+x side) of the optical element 141B.

[0103] Back to Fig.11 The optical element 141B is arranged so that the optical axis of the optical element 141B (a line passing through the center line of the second exit surface 141b and perpendicular to the incident surface 141i (a normal line to the incident surface 141i, Fig. 12B The axis indicated by reference numeral 1415 in the figure is consistent with the optical axis of other optical systems 142 and the light-emitting unit 11.

[0104] As shown in the figure, the light emitted from the light emitting unit 11 is incident on the optical element 141B through the other optical system 142. Thus, the first transmitted light refracted by the first emission surface 141a toward the first field of view 51a, the second transmitted light transmitted through the second emission surface 141b toward the second field of view 51b, and the third transmitted light refracted by the third emission surface 141c toward the third field of view 51c are emitted from the optical element 141B.

[0105] In this way, by using the optical element 141B as an element of the light projection optical system 14B, the field of view (FOV) of the light projector can be easily expanded to a wide range from the first field of view 51a to the third field of view 51c without increasing the light emitting area of ​​the light emitting unit 11 (without increasing the number of light emitting elements). In addition, by adjusting the inclination angles θ1 and θ2, the light projection range (the first field of view 51a and the third field of view 51c) can be adjusted, and the specifications required by the system of the application target of the measuring device 100B can be flexibly responded to.

[0106] The embodiments of the present disclosure are described in detail above, but the present disclosure is not limited to the above embodiments, and includes various modified examples. In addition, the above embodiments describe the structure in detail in order to easily explain the present disclosure, and are not limited to having all the structures described. In addition, a part of the structure of the above embodiments can be added, deleted, or replaced in other structures.

[0107] For example, the above description takes the case where there are three viewing ranges (light projection range, light receiving range) (first viewing range 51a, second viewing range 51b, third viewing range 51c) as an example, but the present disclosure can also be applied to the case where there are two viewing ranges or the case where there are four or more viewing ranges.

[0108] In addition, for example, the structures of the light projector and the light receiver described above (the structure using the diffraction grating 151 as an element of the light receiving optical system 15, the structure using the diffraction grating 141 as an element of the light projecting optical system 14) can be applied to the measuring device 100 in both cases, or only one of them can be applied.

[0109] For example, in the above, the field of view is expanded using diffracted light of three different orders (+1st order, 0th order, and -1st order) of the diffraction grating, but the field of view may be expanded using diffracted light of orders other than these.

[0110] In addition, for example, the structures of the light projector and the light receiver described above (a structure in which the optical element 151B is used as an element of the light receiving optical system 15B, and a structure in which the optical element 141B is used as an element of the light projecting optical system 14B) can be applied to both of them in the measuring device 100B, or only one of them can be applied.

[0111] This application claims priority based on Japanese Application No. 2022-120204 filed on July 28, 2022 and Japanese Application No. 2022-120205 filed on July 28, 2022, and cites all the contents described in the above Japanese Applications.

Claims

1. A measuring device, wherein: The measuring device includes a light projector and a light receiver for receiving reflected light generated by the light projector projecting light toward a field of view. The light receiver includes a light receiving portion and a transmission type diffraction grating. The diffraction grating is configured so that the first reflected light from the first field of view enters the light receiving portion as the first order of diffracted light, and the second reflected light from the second field of view parallel to the first field of view enters the light receiving portion as the second order of diffracted light.

2. The measuring device according to claim 1, wherein The light projector projects light toward the first viewing range and the second viewing range at different timings, respectively.

3. The measuring device according to claim 1, wherein The light receiving unit includes a plurality of light receiving elements. The diffraction grating is configured such that the arrangement direction of the slits of the diffraction grating is consistent with the arrangement direction of the first field of view range and the second field of view range, The light projector projects light toward a portion of the first field of view and a portion of the second field of view simultaneously, and the portion of the first field of view and the portion of the second field of view are in a relationship where the first reflected light and the second reflected light do not enter the same light receiving element.

4. The measuring device according to claim 1, wherein The light receiving unit includes a plurality of light receiving elements arranged in a planar shape. The light projector simultaneously projects light to a strip area from the first field of view to the second field of view. The diffraction grating is arranged in a positional relationship such that the arrangement direction of the slits of the diffraction grating is rotated by a predetermined angle around the optical axis of the diffraction grating relative to the extending direction of the band-shaped region, so that the first reflected light and the second reflected light are respectively incident on different light receiving elements.

5. A measuring device, wherein: The measuring device includes a light projector and a light receiver for receiving reflected light generated by the light projector projecting light toward a field of view. The light receiver includes a light receiving portion and a transmission type diffraction grating. The diffraction grating is configured such that The first reflected light from the first field of view is incident on the light receiving unit as +1-order diffracted light. The second reflected light from the second field of view parallel to the first field of view enters the light receiving unit as 0th order diffracted light. The third reflected light from the third viewing range which is parallel to the second viewing range in the direction from the first viewing range to the second viewing range enters the light receiving unit as −1st order diffracted light.

6. The measuring device according to claim 5, wherein: The light projector projects light toward the first viewing range, the second viewing range, and the third viewing range at different timings.

7. The measuring device according to claim 5, wherein: The light receiving unit includes a plurality of light receiving elements arranged in a planar shape. The diffraction grating is configured such that the arrangement direction of the slits of the diffraction grating is consistent with the arrangement direction from the first field of view range to the third field of view range, The projector projects light toward a portion of the first field of view, a portion of the second field of view, and a portion of the third field of view simultaneously, and a portion of the first field of view, a portion of the second field of view, and a portion of the third field of view are in a relationship where the first reflected light, the second reflected light, and the third reflected light do not enter the light receiving element.

8. The measuring device according to claim 5, wherein: The light receiving unit includes a plurality of light receiving elements arranged in a planar shape. The light projector simultaneously projects light to a strip area from the first field of view to the third field of view. The diffraction grating is arranged in a positional relationship such that the arrangement direction of the slits of the diffraction grating is rotated by a predetermined angle around the optical axis of the diffraction grating relative to the extension direction of the band-shaped region, so that the first reflected light, the second reflected light, and the third reflected light are respectively incident on different light receiving elements.

9. A light receiver, the light receiver receiving reflected light generated by a light projector projecting light toward a field of view, wherein: The light receiver includes a light receiving portion and a transmission type diffraction grating. The diffraction grating is configured so that the first reflected light from the first field of view enters the light receiving portion as the first order of diffracted light, and the second reflected light from the second field of view parallel to the first field of view enters the light receiving portion as the second order of diffracted light.

10. A light receiver, the light receiver receiving reflected light generated by a light projector projecting light toward a field of view, wherein: The light receiver includes a light receiving portion and a transmission type diffraction grating. The diffraction grating is configured such that The first reflected light from the first field of view is incident on the light receiving unit as +1-order diffracted light. The second reflected light from the second field of view parallel to the first field of view enters the light receiving unit as 0th order diffracted light. The third reflected light from the third viewing range which is parallel to the second viewing range in the direction from the first viewing range to the second viewing range enters the light receiving unit as −1st order diffracted light.

11. A measuring device, wherein: The measuring device includes a light projector and a light receiver for receiving reflected light generated by the light projector projecting light toward a field of view. The light projector includes a light emitting unit and a transmission type diffraction grating. The diffraction grating is configured to emit a first order of diffracted light generated by light from the light-emitting portion passing through the diffraction grating toward a first field of view, and to emit a second order of diffracted light generated by light passing through the diffraction grating toward a second field of view parallel to the first field of view.

12. A measuring device, wherein: The measuring device includes a light projector and a light receiver for receiving reflected light generated by the light projector projecting light toward a field of view. The light projector includes a light emitting unit and a transmission type diffraction grating. The diffraction grating is configured such that emits +1st order diffracted light generated by the light from the light emitting unit passing through the diffraction grating toward the first field of view, emitting 0th-order diffracted light generated by the light passing through the diffraction grating toward a second field of view parallel to the first field of view, The -1st order diffracted light generated by the light passing through the diffraction grating is emitted toward a third viewing range that is parallel to the second viewing range in a direction from the first viewing range to the second viewing range.

13. A light projector, the light projector projects light toward a field of view, wherein: The light projector includes a light emitting unit and a transmission type diffraction grating. The diffraction grating is configured such that emitting a first-order diffracted light generated by the light from the light emitting portion passing through the diffraction grating toward a first field of view, The second-order diffracted light generated by the light passing through the diffraction grating is emitted toward a second viewing range parallel to the first viewing range.

14. A light projector, the light projector projects light toward a field of view, wherein: The light projector includes a light emitting unit and a transmission type diffraction grating. The diffraction grating is configured such that emits +1st order diffracted light generated by the light from the light emitting unit passing through the diffraction grating toward the first field of view, emitting 0th-order diffracted light generated by the light passing through the diffraction grating toward a second field of view parallel to the first field of view, The -1st order diffracted light generated by the light passing through the diffraction grating is emitted toward a third viewing range that is parallel to the second viewing range in a direction from the first viewing range to the second viewing range.

15. A measuring device, wherein: The measuring device includes a light projector and a light receiver for receiving reflected light generated by the light projector projecting light toward a field of view. The light receiver includes a light receiving portion and a transmissive optical element. The optical element has: a first incident surface, wherein the first reflected light from the first field of view is incident on the first incident surface; a second incident surface, the second incident surface being formed continuously with the first incident surface and receiving second reflected light from a second field of view continuous with the first field of view; an exit surface, the exit surface causing the first reflected light and the second reflected light to exit toward the light receiving portion; The first incident surface, the second incident surface and the exit surface are all flat surfaces, The second incident surface is inclined relative to the first incident surface with a boundary line with the first incident surface as a fold.

16. The measuring device according to claim 15, wherein The light projector projects light toward the first viewing range and the second viewing range at different timings, respectively.

17. The measuring device according to claim 15, wherein The light receiving unit includes a plurality of light receiving elements. The light projector projects light toward the first viewing range and the second viewing range so that the first reflected light and the second reflected light are respectively incident on different light receiving elements.

18. The measuring device according to claim 15, wherein The light receiving unit includes a plurality of light receiving elements arranged in a planar shape. The second incident surface is also inclined relative to the first incident surface along the boundary line, The light projector simultaneously projects light onto a strip-shaped area from the first viewing range to the second viewing range, so that the first reflected light and the second reflected light are respectively incident on different light receiving elements of the light receiving unit.

19. A measuring device, wherein: The measuring device includes a light projector and a light receiver for receiving reflected light generated by the light projector projecting light toward a field of view. The light receiver includes a light receiving portion and a transmissive optical element. The optical element has: a first incident surface, wherein the first reflected light from the first field of view is incident on the first incident surface; a second incident surface, the second incident surface being continuously formed with the first incident surface and being incident on the second reflected light from a second field of view; a third incident surface, the third incident surface being continuously formed with the second incident surface and being incident on the third reflected light from a third field of view; an exit surface, the exit surface causing the first reflected light, the second reflected light, and the third reflected light to be emitted toward the light receiving portion; The first incident surface, the second incident surface, the third incident surface and the exit surface are all flat surfaces, The first incident surface is inclined relative to the second incident surface with a first boundary line with the second incident surface as a fold, The third incident surface is inclined relative to the second incident surface with a second boundary line with the second incident surface as a fold.

20. The measuring device according to claim 19, wherein The light projector projects light toward the first viewing range, the second viewing range, and the third viewing range at different timings.

21. The measuring device according to claim 19, wherein The light receiving unit includes a plurality of light receiving elements. The light projector projects light toward the first viewing range, the second viewing range, and the third viewing range, so that the first reflected light, the second reflected light, and the third reflected light are respectively incident on different light receiving elements.

22. The measuring device according to claim 19, wherein The light receiving unit includes a plurality of light receiving elements arranged in a planar shape. The first incident surface is also inclined relative to the second incident surface along the first boundary line, The third incident surface is also inclined relative to the second incident surface along the second boundary line in a direction opposite to the first incident surface, The light projector simultaneously projects light on a strip-shaped area from the first viewing range to the third viewing range, so that the first reflected light, the second reflected light, and the third reflected light are respectively incident on different light receiving elements of the light receiving unit.

23. A light receiver, the light receiver receiving reflected light generated by a light projector projecting light toward a field of view, wherein: The light receiver includes a light receiving portion and a transmissive optical element. The optical element has: a first incident surface, wherein the first reflected light from the first field of view is incident on the first incident surface; a second incident surface, the second incident surface being formed continuously with the first incident surface and receiving second reflected light from a second field of view continuous with the first field of view; an exit surface, the exit surface causing the first reflected light and the second reflected light to exit toward the light receiving portion; The first incident surface, the second incident surface and the exit surface are all flat surfaces, The second incident surface is inclined relative to the first incident surface with a boundary line with the first incident surface as a fold.

24. The light receiver according to claim 23, wherein: The light receiving unit includes a plurality of light receiving elements arranged in a planar shape. The second incident surface is also inclined relative to the first incident surface along the boundary line.

25. A light receiver, the light receiver receiving reflected light generated by a light projector projecting light toward a field of view, wherein: The light receiver includes a light receiving portion and a transmissive optical element. The optical element has: a first incident surface, wherein the first reflected light from the first field of view is incident on the first incident surface; a second incident surface, the second incident surface being continuously formed with the first incident surface and being incident on the second reflected light from a second field of view; a third incident surface, the third incident surface being continuously formed with the second incident surface and being incident on the third reflected light from a third field of view; an exit surface, the exit surface causing the first reflected light, the second reflected light, and the third reflected light to be emitted toward the light receiving portion; The first incident surface, the second incident surface, the third incident surface and the exit surface are all flat surfaces, The first incident surface is inclined relative to the second incident surface with a first boundary line with the second incident surface as a fold, The third incident surface is inclined relative to the second incident surface with a second boundary line with the second incident surface as a fold.

26. The light receiver according to claim 25, wherein: The light receiving unit includes a plurality of light receiving elements arranged in a planar shape. The first incident surface is also inclined relative to the second incident surface along the first boundary line, The third incident surface is also inclined relative to the second incident surface along the second boundary line in a direction opposite to the first incident surface.

27. A measuring device, wherein: The measuring device includes a light projector and a light receiver for receiving reflected light generated by the light projector projecting light toward a field of view. The light projector includes a light emitting unit and a transmissive optical element. The optical element has: an incident surface, the incident surface being incident on the light from the light emitting portion; a first emitting surface, wherein the first emitting surface emits light incident on the incident surface toward a first field of view; a second emitting surface, the second emitting surface emitting light incident on the incident surface toward a second field of view; The incident surface, the first exit surface and the second exit surface are all flat surfaces, The second emission surface is inclined relative to the first emission surface with a boundary line with the second emission surface as a fold.

28. A measuring device, wherein: The measuring device includes a light projector and a light receiver for receiving reflected light generated by the light projector projecting light toward a field of view. The light projector includes a light emitting unit and a transmissive optical element. The optical element has: an incident surface, the incident surface being incident on the light from the light emitting portion; a first emitting surface, wherein the first emitting surface emits light incident on the incident surface toward a first field of view; a second emitting surface, the second emitting surface emitting light incident on the incident surface toward a second field of view; a third emitting surface, the third emitting surface emitting light incident on the incident surface toward a third field of view; The incident surface, the first exit surface, the second exit surface and the third exit surface are all flat surfaces, The first emission surface is inclined relative to the second emission surface with a first boundary line with the second emission surface as a fold, The third emission surface is inclined relative to the second emission surface with a second boundary line with the second emission surface as a fold.

29. A light projector, the light projector projects light toward a field of view, wherein: The light projector includes a light emitting unit and a transmissive optical element. The optical element has: an incident surface, the incident surface being incident on the light from the light emitting portion; a first emitting surface, wherein the first emitting surface emits light incident on the incident surface toward a first field of view; a second emitting surface, the second emitting surface emitting light incident on the incident surface toward a second field of view; The incident surface, the first exit surface and the second exit surface are all flat surfaces, The second emission surface is inclined relative to the first emission surface with a boundary line with the second emission surface as a fold.

30. A light projector, the light projector projects light towards a field of view, wherein: The light projector includes a light emitting unit and a transmissive optical element. The optical element has: an incident surface, the incident surface being incident on the light from the light emitting portion; a first emitting surface, wherein the first emitting surface emits light incident on the incident surface toward a first field of view; a second emitting surface, the second emitting surface emitting light incident on the incident surface toward a second field of view; a third emitting surface, the third emitting surface emitting light incident on the incident surface toward a third field of view; The incident surface, the first exit surface, the second exit surface and the third exit surface are all flat surfaces, The first emission surface is inclined relative to the second emission surface with a first boundary line with the second emission surface as a fold, The third emission surface is inclined relative to the second emission surface with a second boundary line with the second emission surface as a fold.

Images