Light detection device

Abstract

A laser radar device (100) is an optical detection device provided with a light emitting unit (20), a scanning unit (30), a light receiving unit (40), and an optical unit (60). In the light emitting unit (20), a plurality of laser oscillation elements (22) that radiate a light beam (SB) are arranged at intervals from each other in a light source arrangement direction (ADs). The scanning unit (30) scans the light beam (SB) radiated from the light emitting unit (20) and performs light projection to a measurement region. The light receiving unit (40) receives a reflected light beam (RB) from the measurement region. The optical unit (60) is located on an optical path of the light beam from the light emitting unit (20) toward the scanning unit (30). The optical unit (60) includes a collimator lens (61) having a positive focal power in a transmission direction of the light beam (SB), and a light beam shaping lens (66) located at a rear stage of the collimator lens (61) and having a positive focal power in the transmission direction on a sub-scanning surface (SS).

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to Japanese Patent Application No. 2020-184033 filed on November 3, 2020, the entire contents of which are incorporated herein by reference. TECHNICAL FIELD

[0003] The disclosure of this specification relates to a light detection device. BACKGROUND

[0004] A distance measuring device is disclosed in Patent Literature 1 that scans an irradiation region outside the device by reflecting laser light radiated from a plurality of end surface emitting lasers or surface emitting lasers arranged in one dimension by a deflection mirror that rotates. The distance measuring device measures the distance to an object present in the irradiation region by receiving reflected light of the laser light irradiated to the irradiation region.

[0005] Patent Literature 1: Japanese Patent No. 6025014

[0006] As in Patent Literature 1, in a structure in which light emitting sections such as end surface emitting lasers or surface emitting lasers are arranged, it is inevitable that gaps that become non-light emitting sections are generated between the plurality of light emitting sections. If such non-light emitting sections exist, non-emission regions are also generated between the respective laser lights irradiated to the irradiation region. Moreover, the non-emission regions of the laser light cause non-detection regions in which an object cannot be detected. As a result, a decrease in the resolution of detection can occur. SUMMARY

[0007] It is an object of the present disclosure to provide a light detection device capable of improving the resolution of detection.

[0008] To achieve the above object, one embodiment disclosed is a light detection device including: a light emitting unit that arranges a plurality of light emitting sections radiating light beams at intervals in a specific arrangement direction; a scanning unit that scans the light beams radiated from the light emitting unit to perform light projection to a measurement region; a light receiving unit that receives return light of the light beams from the measurement region; and an optical unit that is located on an optical path of the light beams from the light emitting unit toward the scanning unit, the optical unit including: a first optical element that has a positive refractive power in a transmission direction of the light beams from the light emitting unit toward the scanning unit; and a second optical element that is located at a rear stage of the first optical element and has a positive refractive power in the transmission direction on a specific cross section that expands in the transmission direction and the specific arrangement direction.

[0009] Another embodiment disclosed is an optical detection device including: a light emitting unit in which a plurality of light emitting sections that radiate light beams are arranged at intervals in a specific arrangement direction; a scanning unit that scans the light beams radiated from the light emitting unit to perform light projection to a measurement region; a light receiving unit that receives return light of the light beams from the measurement region; and an optical unit that is located on an optical path of the light beams from the light emitting unit toward the scanning unit, the optical unit including: a first optical element having a positive focal power in a transmission direction of the light beams from the light emitting unit toward the scanning unit; and a second optical element located at a rear stage of the first optical element, the second optical element causing diffracted light to be generated in a specific cross section that expands in the transmission direction and the specific arrangement direction.

[0010] In this embodiment, each of the light beams radiated from the plurality of light emitting sections arranged in the specific arrangement direction is adjusted in a traveling direction in the first optical element, and then expanded in the specific arrangement direction within the specific cross section by the positive focal power of the second optical element or the generation of the diffracted light. Therefore, even if there is a non-light emitting section between the plurality of light emitting sections in the light emitting unit, a gap that causes a non-detection region is not easily generated between each of the light beams that perform light projection to the measurement region. Thus, the resolution of detection of the optical detection device can be improved.

[0011] Another embodiment disclosed is an optical detection device including: a light emitting unit in which a plurality of light emitting sections that radiate light beams are arranged at intervals in a specific arrangement direction; a scanning unit that scans the light beams radiated from the light emitting unit to perform light projection to a measurement region; a light receiving unit that receives return light of the light beams from the measurement region; and an optical unit that is located on an optical path of the light beams from the light emitting unit toward the scanning unit, the optical unit including: a first optical element that forms a first cylindrical lens surface having a positive focal power in a transmission direction of the light beams from the light emitting unit toward the scanning unit, and is arranged in a posture such that a generatrix direction of the first cylindrical lens surface is along the specific arrangement direction; and a second optical element located at a rear stage of the first optical element, the second optical element forming a second cylindrical lens surface having a positive or negative focal power in the transmission direction, and being arranged in a posture such that a direction perpendicular to a generatrix of the second cylindrical lens surface is along the specific arrangement direction.

[0012] In this embodiment, each of the light beams radiated from the plurality of light emitting sections arranged in the specific arrangement direction is adjusted in a traveling direction in the first cylindrical lens surface, and then expanded in the specific arrangement direction by the positive or negative focal power of the second cylindrical lens surface. Therefore, even if there is a non-light emitting section between the plurality of light emitting sections in the light emitting unit, a gap that causes a non-detection region is not easily generated between each of the light beams that perform light projection to the measurement region. Thus, the resolution of detection of the optical detection device can be improved.

[0013] Another embodiment disclosed is a light detection device including: a light emitting unit in which a plurality of light emitting portions that radiate light beams are arranged at intervals in a specific arrangement direction; a scanning unit that scans the light beams radiated from the light emitting unit to perform light projection to a measurement region; a light receiving unit that receives return light of the light beams from the measurement region; and an optical unit that is located on an optical path of the light beams from the light emitting unit toward the scanning unit, the optical unit including: a homogenizer that makes the intensity of each of the light beams radiated from the plurality of light emitting portions uniform in the specific arrangement direction; and a shaping optical element that is located at a rear stage of the homogenizer and shapes the light beams imaged by the homogenizer into a linear shape extending in the specific arrangement direction.

[0014] In this embodiment, each of the light beams radiated from the plurality of light emitting portions arranged in the specific arrangement direction is made uniform in intensity in the specific arrangement direction in the homogenizer, and then shaped into a linear shape extending in the specific arrangement direction in the shaping optical element. Therefore, even if there is a non-light emitting portion between the plurality of light emitting portions in the light emitting unit, a gap that causes a non-detection region is not easily generated between each of the light beams that project light to the measurement region. Thus, the resolution of detection of the light detection device can be improved.

[0015] In addition, the reference numbers in parentheses in the claims and the like are only one example of a correspondence relationship with the specific configurations in the embodiments described later, and do not limit the technical scope in any way. BRIEF DESCRIPTION OF DRAWINGS

[0016] Figure 1 is a view that shows the configuration of a laser radar device of a first embodiment of the present disclosure.

[0017] Figure 2 is a view that shows the optical action of the optical unit in the sub-scanning surface.

[0018] Figure 3 is a view that shows the optical action of the optical unit in the main-scanning surface.

[0019] Figure 4 is a view that shows the structure of the optical unit on the sub-scanning surface.

[0020] Figure 5 is a view that shows the structure of the optical unit on the main-scanning surface.

[0021] Figure 6 is a view that shows the optical action of the optical unit on the sub-scanning surface of a comparative example.

[0022] Figure 7 is a view that shows the optical action in the sub-scanning surface of the optical unit of a second embodiment of the present disclosure.

[0023] Figure 8is a view that illustrates an optical action in a sub-scanning plane of the optical unit of the third embodiment of the present disclosure.

[0024] Figure 9 is a view that illustrates an optical action in a sub-scanning plane of the optical unit of the fourth embodiment of the present disclosure.

[0025] Figure 10 is a view that illustrates an optical action in a sub-scanning plane of the optical unit of the fifth embodiment of the present disclosure.

[0026] Figure 11 is a view that illustrates an optical action in a main-scanning plane of the optical unit of the fifth embodiment of the present disclosure.

[0027] Figure 12 is a view that illustrates an optical action in a sub-scanning plane of the optical unit of the sixth embodiment of the present disclosure.

[0028] Figure 13 is a view that illustrates an optical action in a sub-scanning plane of the optical unit of the seventh embodiment of the present disclosure.

[0029] Figure 14 is a view that illustrates an optical action in a main-scanning plane of the optical unit of the seventh embodiment of the present disclosure.

[0030] Figure 15 is a view that illustrates an optical action in a sub-scanning plane of the optical unit of the eighth embodiment of the present disclosure.

[0031] Figure 16 is a view that illustrates an optical action in a main-scanning plane of the optical unit of the eighth embodiment of the present disclosure.

[0032] Figure 17 is a view that illustrates an optical action in a sub-scanning plane of the optical unit of the first modification of the present disclosure. DETAILED DESCRIPTION

[0033] Hereinafter, a plurality of embodiments of the present disclosure will be described based on the drawings. In addition, sometimes, by adding the same reference numerals to the corresponding constituent elements in each embodiment, the repeated description is omitted. In each embodiment, only a part of the constitution is described, and the other part of the constitution can apply the constitution of the other embodiment described in the previous description. In addition, not only the combination of the constitution explicitly described in the description of each embodiment, but also the combination of the constitution of each of the plurality of embodiments can be partially combined with each other even if not explicitly described, as long as the combination does not particularly cause hindrance. Furthermore, the combination of the constitution of each of the plurality of embodiments and the modification described in the present disclosure is also disclosed by the following description.

[0034] (First Embodiment)

[0035] Figures 1-3The laser radar (LiDAR, Light Detection and Ranging / Laser Imaging Detection and Ranging) device 100 of the first embodiment of the present disclosure shown functions as a light detection device. The laser radar device 100 is mounted on a vehicle as a moving body. The laser radar device 100 is disposed, for example, at a front portion, left and right side portions, a rear portion, or a roof of the vehicle. The laser radar device 100 scans a prescribed surrounding area (hereinafter, referred to as a measurement area) of the vehicle outside the device by a projection light beam PB. The laser radar device 100 detects a return light (hereinafter, referred to as a reflection light beam RB) caused by reflection of the projection light beam PB irradiated to the measurement area by a measurement target object. The projection light beam PB generally uses light in the near-infrared region that is difficult for a person outside to visually confirm.

[0036] The laser radar device 100 is able to perform measurement of the measurement target object by detection of the reflection light beam RB. The measurement of the measurement target object is, for example, measurement of a direction (relative direction) in which the measurement target object exists, measurement of a distance (relative distance) from the laser radar device 100 to the measurement target object, and the like. In the laser radar device 100 applied to a vehicle, representative measurement target objects are moving objects such as pedestrians, cyclists, animals other than humans, and other vehicles, and stationary objects such as guardrails, road signs, roadside structures, and fallen objects on the road.

[0037] In addition, unless otherwise specified, each direction indicated by front and back, up and down, left and right is defined with reference to a vehicle that is stationary on a horizontal plane. In addition, the horizontal direction indicates a tangential direction with respect to the horizontal plane, and the vertical direction indicates a perpendicular direction with respect to the horizontal plane.

[0038] The laser radar device 100 has a light emitting unit 20, a scanning unit 30, a light receiving unit 40, a controller 50, and an optical unit 60, and a housing that houses these components.

[0039] The housing forms an outer shell of the laser radar device 100. The housing is composed of a light-shielding container and a cover plate, and the like. The light-shielding container is formed of synthetic resin or metal having light-shielding properties, and is a substantially rectangular parallelepiped box as a whole. A housing chamber and an optical window are formed in the light-shielding container. The housing chamber houses main optical components of the laser radar device 100. The optical window is a rectangular-shaped opening that allows both the projection light beam PB and the reflection light beam RB to reciprocate between the housing chamber and the measurement region. The cover plate is, for example, a cover formed of a light-transmissive material such as synthetic resin or glass. A transmission portion that transmits the projection light beam PB and the reflection light beam RB is formed in the cover plate. The cover plate is assembled to the light-shielding container in a state where the cover plate is disposed so as to block the optical window of the light-shielding container through the transmission portion. The housing is held to the vehicle in a posture where the long side direction of the optical window is along the horizontal direction of the vehicle.

[0040] The light emitting unit 20 has a plurality of laser oscillation elements 22. Each laser oscillation element 22 is electrically connected to the controller 50. Each laser oscillation element 22 radiates a light beam SB from each laser radiation window 24 at a light emission timing corresponding to an electric signal from the controller 50.

[0041] Each laser oscillation element 22 employs a laser diode. Each laser oscillation element 22 has a resonator structure. The resonator structure is a configuration that includes an active layer bonded between a P-type semiconductor and an N-type semiconductor, and a pair of reflecting mirrors disposed on both end surfaces of the active layer. In the resonator structure, electrons and holes are supplied to the active layer by applying a voltage to each semiconductor. The electrons and the holes emit light by recombination within the active layer. The light generated within the active layer is amplified by stimulated emission, and becomes coherent laser light in which phases are consistent by repetition based on reflection by the pair of reflecting mirrors disposed on both sides of the active layer. The resonator structure causes the laser light in a phase-in-phase state to be radiated through the laser radiation window 24, which is a semi-transparent mirror, provided to one of the reflecting mirrors. This light beam-shaped laser light (hereinafter referred to as a light beam SB) constitutes a part of the projection light beam PB. That is, a collection of the light beams SB oscillated from the plurality of laser oscillation elements 22 becomes the projection light beam PB.

[0042] As one example, the above laser oscillation element 22 employs an edge-emitting type element that emits a light beam SB from a side surface of the resonator structure. Alternatively, the laser oscillation element 22 can employ a vertical cavity surface emitting laser (VCSEL) that vertically configures the resonator structure with respect to a semiconductor substrate. The VCSEL emits a light beam SB in a vertical direction with respect to the semiconductor substrate.

[0043] The plurality of laser oscillation elements 22 are arranged in the long-side rectangular light emitting region 21 having the specific light source arrangement direction Ads as a long side on the main substrate of the light emitting unit 20. The light emitting region 21 is a region in which the laser oscillation elements 22 are mounted on the main substrate. The light emitting region 21 can be a planar region along the Z-X plane (described later), a planar region along the X-Y plane (described later), or a three-dimensional space region as long as it is a long-side shape having the light source arrangement direction Ads as a long side. The shape of the light emitting region 21 can be, for example, an elliptical shape or the like. The plurality of laser oscillation elements 22 are arranged at intervals from each other in the light emitting region 21 in the light source arrangement direction Ads. The plurality of laser oscillation elements 22 can be arranged in a single column (one column) or in a plurality of columns.

[0044] The laser emission window 24 described above is formed in each laser oscillation element 22 in a rectangular shape. Each laser oscillation element 22 is mounted on the main substrate so that the long-side direction of the laser emission window 24 is oriented along the light source arrangement direction Ads. By the arrangement of the plurality of laser emission windows 24 in a column, a thin strip-shaped laser light emission opening 25 extending in the light source arrangement direction Ads is formed in the light emitting region 21. The normal line on the center of the laser light emission opening 25 becomes an optical axis (hereinafter referred to as a beam optical axis BLA) of the light beam SB emitted from the laser light emission opening 25. In addition, the dimension in the light source arrangement direction Ads of the laser light emission opening 25 is, for example, 100 times or more with respect to the dimension in the width direction perpendicular to the light source arrangement direction Ads.

[0045] In addition, a light source structure in which a thin strip-shaped laser emission window is formed in one laser oscillation element instead of the laser light emission opening 25 constituted by the plurality of laser emission windows 24 is assumed. However, in such a light source structure, a decrease in light emission efficiency occurs, so it becomes difficult to secure the output of the light beam SB. In contrast to this, the above-described configuration in which the plurality of laser oscillation elements 22 are arranged in an array shape is suitable for forming a simulated thin elongated laser light emission opening 25 while securing the overall output of the light beam SB. However, a prescribed gap is secured between the elements of the plurality of laser oscillation elements 22, for example, for cooling properties, manufacturability, and securing of light emission efficiency, and the like. As a result, a non-light emission portion 23x (refer to FIG. 2) caused by the gap between the laser oscillation elements 22 inevitably occurs in the laser light emission opening 25. Figure 2

[0046] The scanning unit 30 scans the light beam SB emitted from each laser oscillation element 22 and projects it to the measurement region as a projection light beam PB. In addition to this, the scanning unit 30 causes a reflected light beam RB reflected in the measurement region to enter the light receiving unit 40. The scanning unit 30 is configured to include a drive motor 31 and a scanning mirror 33, and the like.

[0047] ​The drive motor 31 is, for example, a voice coil motor, a brush DC motor, or a step motor. The drive motor 31 has a shaft portion 32 mechanically coupled to the scanning mirror 33. The shaft portion 32 is disposed in a posture along the light source arrangement direction Ads of the laser oscillation element 22, and defines a rotation axis As of the scanning mirror 33. The rotation axis As is in a posture along the light source arrangement direction Ads, and is substantially parallel to the light source arrangement direction Ads. The drive motor 31 drives the shaft portion 32 with a rotation amount and a rotation speed corresponding to an electric signal from the controller 50.

[0048] The scanning mirror 33 performs a reciprocating rotation around the rotation axis As defined by the shaft portion 32 with the rotation axis As as a center of rotation, and performs a swinging motion within a limited angle range RA. The angle range RA of the scanning mirror 33 can be set by a mechanical stopper, an electromagnetic stopper, or drive control. The angle range RA is limited so that the projection light beam PB does not escape from the optical window of the housing.

[0049] The scanning mirror 33 has a main body portion 35 and a reflecting surface 36. The main body portion 35 is formed in a flat plate shape, for example, by glass or synthetic resin. The main body portion 35 is coupled to the shaft portion 32 of the drive motor 31 using a mechanical member formed of metal or the like. The reflecting surface 36 is a mirror surface formed by evaporating a metal film of aluminum, silver, gold, or the like on a surface of one side of the main body portion 35, and further forming a protective film of silicon dioxide or the like on the evaporated surface. The reflecting surface 36 is formed in a smooth rectangular planar shape. The reflecting surface 36 is disposed in a posture with the long side direction along the rotation axis As. As a result, the long side direction of the reflecting surface 36 substantially coincides with the light source arrangement direction Ads.

[0050] The scanning mirror 33 is disposed commonly to the projection light beam PB and the reflected light beam RB. That is, the scanning mirror 33 uses a part of the reflecting surface 36 as a light projection reflecting portion 37 used for light projection of the projection light beam PB, and uses another part of the reflecting surface 36 as a light receiving reflecting portion 38 used for light reception of the reflected light beam RB. The light projection reflecting portion 37 and the light receiving reflecting portion 38 can be defined as mutually separate regions on the reflecting surface 36, or can be defined as regions at least partially overlapping.

[0051] The scanning mirror 33 changes the deflection direction of the projection light beam PB according to a change in the orientation of the reflecting surface 36. The scanning mirror 33 moves the projection light beam PB irradiating the measurement region by rotation of the drive motor 31, and thereby scans the measurement region in time and space. The scanning of such a scanning mirror 33 becomes scanning around only the rotation axis As, and becomes one-dimensional scanning that omits scanning in the light source arrangement direction Ads.

[0052] By the above configuration, a plane orthogonal to the rotation axis AS in essence becomes the main scanning surface MS of the scanning mirror 33. On the other hand, a plane along both the beam optical axis BLA of the light beam SB that is emitted from the light emitting unit 20 into the scanning unit 30 and the rotation axis AS (in essence, parallel) becomes the sub-scanning surface SS of the scanning mirror 33. The main scanning surface MS and the sub-scanning surface SS are mutually orthogonal planes. The light source arrangement direction Ads is a direction in essence parallel to the sub-scanning surface SS, and becomes a direction in essence perpendicular to the main scanning surface MS. The scanning of the scanning mirror 33 becomes scanning that moves the irradiation range of the linear projection light beam PB that extends elongatedly along the light source arrangement direction Ads to and fro along the main scanning surface MS.

[0053] Here, in the vehicle-mounted state of the laser radar device 100, the posture becomes such that the light source arrangement direction Ads, the rotation axis AS, and the sub-scanning surface SS are along the vertical direction. On the other hand, the posture becomes such that the beam optical axis BLA and the main scanning surface MS are along the horizontal direction. By the above, the shape of the projection light beam PB that is irradiated to the measurement region becomes linear that extends elongatedly in the vertical direction, and determines the vertical angle of view of the laser radar device 100. On the other hand, the limited angle range RA at the time of scanning of the scanning mirror 33 defines the irradiation range of the projection light beam PB, and thus determines the horizontal angle of view in the laser radar device 100.

[0054] The light receiving unit 40 receives the reflected light beam RB from the measurement region. The reflected light beam RB is the projection light beam PB that has passed through the optical window of the housing, has been reflected by the measurement target existing in the measurement region, has passed through the optical window again, and has been emitted into the scanning mirror 33. Since the speed of the projection light beam PB and the reflected light beam RB is sufficiently large with respect to the rotation speed of the scanning mirror 33, the phase shift of the projection light beam PB and the reflected light beam RB is small to the extent that it can be ignored. Therefore, the reflected light beam RB is reflected by the reflection surface 36 at substantially the same reflection angle as the projection light beam PB, and is guided to the light receiving unit 40 in the direction opposite to the projection light beam PB.

[0055] The light receiving unit 40 is configured to include a detection section 41 and a light receiving lens 44, and the like. The detection section 41 is provided with a detection surface 42 and a decoder. The detection surface 42 is formed of a plurality of light receiving elements. The plurality of light receiving elements are arranged in an arrayed shape in a highly integrated state, and form an element array of a long-side rectangular shape in the detection surface 42. The long-side direction of the detection surface 42 is along the long-side direction of the laser light emission opening 25, that is, the light source arrangement direction Ads, and is in essence parallel to the light source arrangement direction Ads. By the above configuration, for the detection surface 42, it is possible to efficiently receive the reflected light beam RB that is linear along the light source arrangement direction Ads in the detection surface 42.

[0056] As an example, the light-receiving elements employ single photon avalanche diodes (hereinafter referred to as SPADs). A SPAD generates an electric pulse through an electron multiplication action based on avalanche multiplication if one or more photons are incident. The SPAD is capable of outputting the electric pulse as a digital signal without passing through an AD conversion circuit. As a result, high-speed readout of the detection result of the condensed reflected light beam RB at the detection surface 42 is enabled. In addition, an element other than a SPAD can be employed as the light-receiving element. For example, a general avalanche photodiode, and other photodiodes, etc. can be employed as the light-receiving element.

[0057] The decoder is a circuit portion that outputs the electric pulse generated by the light-receiving element to the outside. The decoder sequentially selects and extracts the target element of the electric pulse from a plurality of light-receiving elements. The decoder outputs the electric pulse of the selected light-receiving element to the controller 50. If the output from all of the light-receiving elements ends, the sampling for one time ends.

[0058] The light-receiving lens 44 is an optical element that is located on the optical path of the reflected light beam RB from the scanning mirror 33 toward the detection portion 41. The light-receiving lens 44 forms a light-receiving optical axis RLA. The light-receiving optical axis RLA is defined as an axis along a virtual light ray that passes through the curvature center of each refractive surface of the light-receiving lens 44. The light-receiving optical axis RLA is substantially parallel to the light beam optical axis BLA. The light-receiving lens 44 condenses the reflected light beam RB that has been reflected at the reflection surface 36 and focuses it onto the detection surface 42. The light-receiving lens 44 condenses the reflected light beam RB that has been reflected at the reflection surface 36 onto the detection surface 42 regardless of the orientation of the scanning mirror 33.

[0059] The controller 50 controls light detection of the measurement region. The controller 50 includes a control circuit portion and a drive circuit portion that drives the laser oscillation element 22 and the motor 31, and the control circuit portion includes a processor, a RAM, a storage portion, an input / output interface, and a bus that connects them, etc. The control circuit portion is, for example, a configuration that mainly employs a microcontroller that includes a CPU (Central Processing Unit) as the processor. The control circuit portion can also be a configuration that mainly employs an FPGA (Field-Programmable Gate Array) or an ASIC (Application Specific Integrated Circuit), etc.

[0060] The controller 50 is electrically connected to each of the laser oscillation elements 22, the drive motor 31, and the detection section 41. The controller 50 has a light emission control section 51, a scanning control section 52, a measurement arithmetic section 53, and the like. Each of the functional sections can be a configuration constructed in software based on a program, or can be a configuration constructed in hardware.

[0061] The light emission control section 51 outputs a drive signal to each of the laser oscillation elements 22 to radiate the light beam SB from each of the laser oscillation elements 22 at a light emission timing in cooperation with the light beam scanning of the scanning mirror 33. The light emission control section 51 causes the light beam SB to oscillate in a short pulse from each of the laser oscillation elements 22. The light emission control section 51 can control the oscillation of the light beam SB of the plurality of laser oscillation elements 22 to be substantially simultaneous, or can set a slight time difference to cause each of the laser oscillation elements 22 to oscillate sequentially.

[0062] The scanning control section 52 outputs a drive signal to the drive motor 31 to achieve the light beam scanning in cooperation with the light beam oscillation of the laser oscillation elements 22.

[0063] The measurement arithmetic section 53 performs arithmetic processing on the electric pulse input from the detection section 41 to determine the presence or absence of the measurement target object on the measurement region. In addition to this, the measurement arithmetic section 53 measures the distance to the measurement target object until the presence is grasped. The measurement arithmetic section 53 counts the number of electric pulses output from each of the light receiving elements of the detection section 41 after the light projection of the projection light beam PB in each sampling. The measurement arithmetic section 53 generates a histogram that records the number of electric pulses for each sampling. The level of the histogram indicates the time of flight (TOF) of light from the time of radiation of the light beam SB to the time of detection of the reflected light beam RB. In addition, the sampling frequency of the detection section 41 corresponds to the time resolution in the TOF measurement.

[0064] The optical unit 60 is a group of optical elements located on the optical path of the light beam SB from the light emission unit 20 toward the scanning unit 30. The optical unit 60 adjusts the shape of the light beam SB radiated from each of the laser oscillation elements 22 to be incident on the reflection surface 36. The optical unit 60 is configured to include a collimator lens 61, a beam shaping lens 66, and a lens barrel 70 (refer to Figure 4 and Figure 5 ).

[0065] Here, in order to describe the detailed configuration of the optical unit 60, an X-axis, a Y-axis, and a Z-axis are defined. The X-axis is orthogonal to the sub-scanning plane SS of the scanning unit 30 and is parallel to the main-scanning plane MS of the scanning unit 30. The X-axis corresponds to the fast axis (speed axis) of the laser light. The Y-axis is parallel to the light source arrangement direction ADs and the rotation axis AS. The Y-axis corresponds to the slow axis (delay axis) of the laser light. The Z-axis is parallel to the beam optical axis BLA from the light emitting region 21 toward the scanning mirror 33. The Z-direction is the transmission direction of the beam SB through the optical unit 60 and is the direction from the light emitting unit 20 toward the scanning unit 30. By the above, the Z-X plane of the optical unit 60 coincides with the main-scanning plane MS of the laser radar device 100 (see Figure 3 ). In addition, the Y-Z plane of the optical unit 60 coincides with the sub-scanning plane SS of the laser radar device 100 (see Figure 2 ).

[0066] The collimator lens 61 is formed of a light-transmissive material having excellent optical properties, such as synthetic quartz glass or synthetic resin. The collimator lens 61 employs an aspherical bi-convex lens. The collimator lens 61 has a convex entrance surface 62 on the light emitting unit 20 side and a convex exit surface 63 on the scanning unit 30 side. The collimator lens 61 is disposed on the optical path of the beam SB so that the beam optical axis BLA passes through the optical centers of the convex entrance surface 62 and the convex exit surface 63. The normal line on the optical centers of the convex entrance surface 62 and the convex exit surface 63, that is, the lens optical axis of the collimator lens 61 substantially coincides with the beam optical axis BLA.

[0067] The collimator lens 61 has a positive focal power in the transmission direction (Z-direction) of the beam SB from the light emitting unit 20 toward the scanning unit 30. The collimator lens 61 generates parallel light along the beam optical axis BLA within the main-scanning plane MS by the optical action of refracting the beam SB of the convex entrance surface 62 and the convex exit surface 63, so that the traveling direction of the beam SB is concentrated on the beam optical axis BLA side. The collimator lens 61 is located at the front stage of the beam shaping lens 66, so that the beam SB which becomes parallel light with respect to the beam optical axis BLA is incident into the beam shaping lens 66.

[0068] The beam shaping lens 66 is located at the rear stage of the collimator lens 61. The beam shaping lens 66 has a positive focal power in the transmission direction (Z-direction) on the sub-scanning plane SS which is expanded in the transmission direction of the beam SB and the light source arrangement direction ADs. The beam shaping lens 66 employs a cylindrical lens 166.

[0069] Cylindrical lens 166, like collimating lens 61, is formed of a light-transmitting material such as synthetic quartz glass or synthetic resin. Cylindrical lens 166 is an optical element with astigmatic properties. Cylindrical lens 166 has an entrance plane 165 and an exit plane 167. The entrance plane 165 is a smooth plane, substantially orthogonal to the optical axis BLA of the light beam. The exit plane 167 is a partially cylindrical surface that is either spherical or aspherical, forming a shape that is convexly curved towards the exit direction (Z direction) on the sub-scanning plane SS.

[0070] Cylindrical lens 166 is configured with a lens profile having positive optical power parallel to the sub-scanning plane SS. The position of cylindrical lens 166 along the X-Y plane is adjusted so that the optical center of the exit surface 167 of the cylindrical lens is on the beam axis BLA. Through the optical effect of refracting the beam SB at both the incident plane 165 and the exit surface 167, cylindrical lens 166 substantially stretches the beam SB in only one direction within the sub-scanning plane SS (see reference). Figure 2 On the other hand, cylindrical lens 166 does not substantially perform an optical function of deflecting beam SB within the main scanning plane MS (see reference). Figure 3 ).

[0071] Figure 4 as well as Figure 5 The lens barrel 70 shown is integrally formed into a cylindrical shape using a light-shielding synthetic resin or metal. The lens barrel 70 houses a collimating lens 61 and a cylindrical lens 166. A glass cover 27 is mounted on the lens barrel 70. The glass cover 27 is a component that protects the laser oscillation element 22. The glass cover 27 can be incorporated into either the light-emitting unit 20 or the optical unit 60. The lens barrel 70 precisely defines the positional relationships of each laser oscillation element 22, collimating lens 61, and beam-shaping lens 66. The lens barrel 70 is housed within a casing or similar structure. This defines the positional relationships between the collimating lens 61 and the cylindrical lens 166 and the reflecting surface 36.

[0072] The lens barrel 70 includes a cylindrical body 71, an injection-side component 72, an intermediate component 75, and an ejection-side component 77. The cylindrical body 71 is formed into a cylindrical shape. The cylindrical body 71 holds the injection-side component 72, the intermediate component 75, and the ejection-side component 77 through its inner peripheral wall.

[0073] The injection-side component 72 is formed into a bottomed cylindrical shape. The injection-side component 72 is embedded in the inner peripheral wall of the cylindrical body 71 with its bottom wall facing the light-emitting unit 20. The injection-side component 72 is located on the light-emitting unit 20 side of the collimating lens 61, restricting the movement of the collimating lens 61 towards the light-emitting unit 20. A field stop 73 is formed on the bottom wall of the injection-side component 72.

[0074] The field stop 73 divides the center of the bottom wall of the incident-side component 72 into an incident-side opening 74. The incident-side opening 74 is formed into a roughly rectangular shape with the light source arrangement direction Ads as its long side. The incident-side opening 74 is located within the main scanning plane MS and is positioned near the composite focal plane FPF of the optical unit 60. The light-emitting unit 20, mounted on the bottom wall of the incident-side component 72, allows the light beams SB radiated from each laser radiation window 24 to enter the lens barrel 70 through the incident-side opening 74. The field stop 73 is located on the incident side of the collimating lens 61, i.e., the pre-stage, and adjusts (limits) the angle of the light beams SB emitted from the laser radiation windows 24.

[0075] The intermediate component 75 is formed in a ring shape and is disposed between the collimating lens 61 and the cylindrical lens 166. The intermediate component 75 restricts the movement of the collimating lens 61 toward the scanning unit 30 and restricts the movement of the cylindrical lens 166 toward the light-emitting unit 20.

[0076] The emission-side component 77 is formed as a bottomed cylindrical shape. The emission-side component 77 is embedded in the inner peripheral wall of the cylindrical body 71 with its bottom wall facing the scanning unit 30. The emission-side component 77 is located on the scanning unit 30 side of the cylindrical lens 166, restricting the movement of the cylindrical lens 166 towards the scanning unit 30 side. An aperture stop 78 is formed on the bottom wall of the emission-side component 77.

[0077] An aperture stop 78 divides the center of the bottom wall of the emission-side component 77 into an emission-side opening 79. The emission-side opening 79 is formed into a roughly rectangular shape with the X-axis as its long side. The emission-side opening 79 is located within the sub-scanning surface SS at the position where the beam SB converges most. The emission-side opening 79 allows the beam SB, which has passed through the cylindrical lens 166, to exit toward the scanning unit 30. The aperture stop 78 is located on the emission side of the cylindrical lens 166, i.e., the rear stage, so that the amount of light emitted by the beam SB to the scanning unit 30 is adjusted to be the same regardless of the emission angle of the beam SB.

[0078] Next, we will further explain in detail the optical effects resulting from the addition of a cylindrical lens 166 after the collimating lens 61.

[0079] exist Figure 6 In the optical unit 60c of the comparative example shown, the beam-shaping lens 66 is omitted. Therefore, the beam SB transmitted through the collimating lens 61 does not extend in the light source alignment direction Ads. Consequently, the non-emitting portion 23x generated within the emitting region 21 between the laser radiation windows 24 also remains as a gap between the beams SB in the projected beam PB. Based on the above, the projected beam PB, composed of multiple beams SB, becomes a discontinuous line broken into multiple segments in the light source alignment direction Ads. The gaps generated between such beams SB become undetected areas NDA where the object under test cannot be detected.

[0080] In contrast, Figure 2 In the optical unit 60 shown, the composite focal plane FPF based on the collimating lens 61 and the cylindrical lens 166 on the incident side is located on the collimating lens 61 side (Z direction) in the sub-scanning plane SS (Y-Z plane) compared to the light-emitting region 21. That is, the light-emitting region 21 is located at a position far away from the optical unit 60 compared to the composite focal plane FPF. Therefore, in the sub-scanning plane SS, the collimating lens 61 and the cylindrical lens 166 perform the optical function of blurring the focus of the laser emission opening 25 and stretching the thin strip-shaped beam SB along the Y-axis. As a result, even if un-emitted portions 23x are generated between the multiple laser radiation windows 24, the undetected region NDA disappears because the beams SB that have passed through the optical unit 60 overlap with each other. Based on the above, the projection beam PB composed of multiple beams SB becomes a line that extends continuously in the light source arrangement direction Ads.

[0081] On the other hand, Figure 3 Within the main scanning plane MS (Z-X plane) shown, the combined focal plane FPF of the collimating lens 61 and the cylindrical lens 166 intersects with the light-emitting region 21. In other words, the distance between the light-emitting region 21 and the optical unit 60 is determined by the position of the combined focal plane FPF. Furthermore, each laser radiation window 24 disposed within the light-emitting region 21 can be slightly offset from the combined focal plane FPF. Specifically, each laser radiation window 24 can be slightly offset in the Z-direction relative to the combined focal plane FPF, or slightly offset in the -Z-direction relative to the combined focal plane FPF.

[0082] Based on the above configuration, the cylindrical lens 166 does not have positive optical power within the main scanning plane MS. Therefore, the beam SB, which becomes parallel light in the collimating lens 61, is transmitted through the cylindrical lens 166 substantially unchanged along the beam optical axis BLA. As a result, the collimating lens 61 and the cylindrical lens 166 can suppress the widening of the thin band-shaped beam SB, forming a linear projection beam PB that maintains a narrow beam width.

[0083] According to the first embodiment described so far, the travel direction of each beam SB radiated from a plurality of laser oscillating elements 22 arranged in a specific light source arrangement direction ADs is adjusted by a collimating lens 61. Furthermore, each beam SB is extended along the light source arrangement direction Ads within the sub-scanning surface SS due to the positive optical power of the beam shaping lens 66. Therefore, even if there are un-emitting portions 23x between the plurality of laser oscillating elements 22 in the light-emitting unit 20, gaps that would cause undetected areas NDA are less likely to occur between the beams SB projected onto the measurement area. Therefore, the detection resolution of the lidar device 100 can be improved.

[0084] In addition, in the first embodiment, within the sub-scanning surface SS, the position of the composite focal plane FPF of the collimator lens 61 and the beam shaping lens 66 is on the collimator lens 61 side as compared with the laser oscillation element 22. According to such a positional relationship of the composite focal plane FPF and the laser oscillation element 22, each light flux SB radiated from each laser oscillation element 22 is influenced by the positive power of the beam shaping lens 66 due to the optical unit 60, and can become a continuous linear shape in which the gap is eliminated. As a result, the non-detection area NDA can be substantially eliminated from the projection light flux PB projected toward the measurement region, so a laser radar device 100 of high resolution can be more reliably achieved.

[0085] In addition, in the first embodiment, the plurality of laser oscillation elements 22 are arranged within the light emitting region 21 in a long side shape having the light source arrangement direction Ads as a long side. If such a configuration is adopted, the projection light flux PB in which the light fluxes SB that have passed through the optical unit 60 are overlapped becomes continuous linear by the optical action of the beam shaping lens 66, and becomes a shape that is elongated along the light source arrangement direction Ads. As a result, the resolution in the direction along the sub-scanning surface SS can be easily ensured.

[0086] In addition, in the first embodiment, within the main scanning surface MS orthogonal to the sub-scanning surface SS and along the transmission direction of the light flux SB, i.e., the Z direction, the light emitting region 21 is disposed at the position of the composite focal plane FPF of the beam shaping lens 66 and the beam shaping lens 66. In this way, if the light emitting region 21 in which the laser oscillation elements 22 are arranged is defined at the position of the composite focal plane FPF, the expansion of the light flux within the main scanning surface MS can be suppressed. As a result, the expansion of the projection light flux projected toward the measurement region can be suppressed, so even if the beam shaping lens 66 is added to the optical path, a decrease in the detection resolution is not easily caused.

[0087] In addition, the optical unit 60 of the first embodiment has a field stop 73 located at a stage prior to the collimator lens 61. The field stop 73 forms an entrance side opening 74 having the light source arrangement direction Ads as a long side. If such a shape of the entrance side opening 74 is formed in the field stop 73, the entrance of the light flux SB that becomes stray light due to the package of the laser oscillation element 22 and the glass cover 27, etc. toward the collimator lens 61 can be effectively suppressed. Therefore, a decrease in the noise generated in the projection light flux PB can be achieved.

[0088] The optical unit 60 of the first embodiment has an aperture stop 78 located at a stage subsequent to the beam-shaping lens 66. The aperture stop 78 forms an emission-side opening 79 having a direction along the X-axis perpendicular to both the light source arrangement direction ADs and the Z-direction as a long side. Such a shaped emission-side opening 79 can transmit the light beam SB that is parallel light with respect to the beam optical axis BLA within the main scanning plane MS and suppress emission of stray light generated at each lens 61, 66, etc. within the sub-scanning plane SS. As a result, reduction of noise generated by the projection light beam PB can be achieved.

[0089] The scanning unit 30 of the first embodiment further has the scanning mirror 33 that rotates around the rotation axis AS along the light source arrangement direction ADs. In this way, if the light source arrangement direction ADs is substantially parallel to the rotation axis AS, scanning of the measurement region using a continuous line light beam as the projection light beam PB can be achieved. Therefore, it is easier to achieve the effect of increasing the resolution of the laser radar device 100.

[0090] In the first embodiment, the optical unit 60 includes the cylindrical lens 166 having a cylindrical lens emission surface 167 that is convexly curved toward the emission side in the sub-scanning plane SS as the beam-shaping lens 66. According to the adoption of the cylindrical lens 166, it is possible to limit the positive focal power to act within the sub-scanning plane SS. As a result, it is easy to achieve both the optical action of stretching the light beam SB within the sub-scanning plane SS and the optical action of imaging the light beam SB within the main scanning plane MS. As a result, it is easier to achieve a high-resolution light detection device.

[0091] In the first embodiment, the cylindrical lens 166 having the same positive focal power as the collimator lens 61 is disposed at a stage subsequent to the collimator lens 61 having the positive focal power. According to such a configuration, it is possible to reduce the curvature of the cylindrical lens emission surface 167. Therefore, it is easy to achieve both the assurance of the manufacturability and the assurance of the shape accuracy of the cylindrical lens 166.

[0092] In the scanning unit 30 of the first embodiment, the reflecting surface 36 is formed on one side surface of the main body portion 35 of the scanning mirror 33, and scanning of the projection light beam PB is performed by the oscillating motion of the scanning mirror 33. If, as a comparative example, both surfaces of the scanning mirror are made reflecting surfaces and the scanning mirror is rotated, in the comparative example, the projection light beam PB does not reach the edge portion of the reflecting surface, so an undetected period in which the irradiation of the projection light beam PB is interrupted occurs. In contrast, if the scanning mirror 33 is oscillated, the above-described undetected period does not substantially occur. Therefore, the scanning in which the scanning mirror 33 is reciprocally rotated is advantageous for increasing the resolution of the laser radar device 100.

[0093] Further, in the first embodiment, the laser oscillation element 22 corresponds to the "light emitting section", the scanning mirror 33 corresponds to the "rotating mirror", the collimator lens 61 corresponds to the "first optical element", and the beam shaping lens 66 corresponds to the "second optical element". Further, the field stop 73 corresponds to the "front-stage stop section", the entrance-side opening 74 corresponds to the "front-stage opening", the opening stop 78 corresponds to the "rear-stage stop section", the exit-side opening 79 corresponds to the "rear-stage opening", and the cylindrical lens exit surface 167 corresponds to the "exit surface". Furthermore, the light source arrangement direction ADs corresponds to the "specific arrangement direction", the main scanning surface MS corresponds to the "orthogonal cross section", the sub-scanning surface SS corresponds to the "specific cross section", and the Z direction corresponds to the "transmission direction of the light beam SB". Moreover, the reflected light beam RB corresponds to the "return light", and the laser radar device 100 corresponds to the "light detection device".

[0094] (Second Embodiment)

[0095] Figure 7 The second embodiment of the present disclosure shown is a modification example of the first embodiment. The optical unit 60 of the second embodiment employs a cylindrical lens 266 as the beam shaping lens 66. The cylindrical lens 266 is formed of a light-transmissive material such as synthetic quartz glass or synthetic resin, like the collimator lens 61. The cylindrical lens 266 includes a plurality of minute plano-convex lens sections 268. The cylindrical lens 266 is an optical element in which the plurality of plano-convex lens sections 268 are continuously arranged.

[0096] Each of the plano-convex lens sections 268 extends linearly along the X axis. The plurality of plano-convex lens sections 268 are continuously arranged along the light source arrangement direction ADs (Y axis). Each of the plano-convex lens sections 268 has a minute entrance surface 265 and a minute exit surface 267. The minute entrance surface 265 is formed as a smooth planar surface. The plurality of minute entrance surfaces 265 of the plano-convex lens sections 268 are continuously arranged without steps in the light source arrangement direction ADs, forming the entrance surface of the cylindrical lens 266. The cylindrical lens 266 is disposed in a posture in which the entrance surface is orthogonal to the light beam optical axis BLA. The minute exit surface 267 is a partial cylindrical surface that is spherical or aspherical, and is curved convexly in the Z direction, that is, the exit side, in the sub-scanning surface SS. The exit surface of the cylindrical lens 266 is formed by continuously arranging the plurality of minute exit surfaces 267 in the light source arrangement direction ADs.

[0097] The cylindrical lens 266 has a positive focal power in the sub-scanning surface SS. The cylindrical lens 266 substantially expands the light beam SB in only one direction in the sub-scanning surface SS by the optical action of refracting the light beam SB of each of the minute entrance surfaces 265 and the minute exit surfaces 267, forming a continuous linear projection light beam PB. In contrast, the cylindrical lens 266 substantially does not exert the optical action of expanding the light beam SB in the main scanning surface MS.

[0098] In the second embodiment described so far, the same effect as the first embodiment is exerted, and even if there is a non-light-emitting portion 23x between the laser oscillation elements 22 arranged in the light-emitting region 21, the projection light beam PB composed of the plurality of light beams SB can be shaped into a continuous line shape. Therefore, high-resolution detection can be achieved.

[0099] In addition, by employing the cylindrical lens 266 as in the second embodiment, it is possible to limit the positive focal power to act within the sub-scanning plane SS. As a result, it is possible to easily achieve both the optical action within the sub-scanning plane SS to stretch the light beam SB and the optical action within the main scanning plane MS to image the light beam SB.

[0100] Furthermore, even if the relative position of the cylindrical lens 266 with respect to the collimator lens 61 is shifted along the X-Y plane, the optical action on the light beam SB does not easily change. In this way, in the manner in which the cylindrical lens 266 is employed as the beam shaping lens 66, it is easy to allow a positional shift of the cylindrical lens 266. In addition, in the second embodiment, the minute emission surface 267 corresponds to the "emission surface".

[0101] (Third Embodiment)

[0102] Figure 8 The third embodiment of the present disclosure shown is another modification example of the first embodiment. The optical unit 60 of the third embodiment employs a Fresnel lens 366 as the beam shaping lens 66. The Fresnel lens 366 is formed of a light-transmissive material such as synthetic quartz glass or synthetic resin, like the collimator lens 61. The Fresnel lens 366 has a Fresnel entrance surface 365 and a Fresnel exit surface 367.

[0103] The Fresnel entrance surface 365 is a smooth planar shape and is substantially orthogonal to the beam optical axis BLA. The Fresnel exit surface 367 has a plurality of divided exit surface portions 368 arranged as a whole to be convexly curved toward the exit side in the sub-scanning plane SS. The divided exit surface portions 368 are elongated along the X axis and are discontinuously arranged in the light source arrangement direction ADs.

[0104] The Fresnel lens 366 is disposed on the optical path of the light beam SB in such a manner that the beam optical axis BLA passes through the respective optical centers of the Fresnel entrance surface 365 and the Fresnel exit surface 367. The normal line on the respective optical centers of the Fresnel entrance surface 365 and the Fresnel exit surface 367, that is, the lens optical axis of the Fresnel lens 366 is substantially coincident with the beam optical axis BLA.

[0105] In the third embodiment described so far, the same effect as the first embodiment is exerted, and even if there is the non-light-emitting portion 23x between the laser oscillation elements 22 arranged on the light-emitting region 21, the continuous linear projection light beam PB can be shaped. Therefore, high-resolution detection can be achieved. In addition to this, according to the adoption of the Fresnel lens 366 as in the third embodiment, the light beam shaping lens 66 can be thinned. Therefore, the optical unit 60 can be miniaturized.

[0106] (Fourth Embodiment)

[0107] Figure 9 The fourth embodiment of the present disclosure shown is another modification example of the first embodiment. The optical unit 460 of the fourth embodiment has a diffractive optical element 466 as an optical element instead of the light beam shaping lens 66 (refer to Figure 2 ). The diffractive optical element 466 is formed as a flat plate as a whole. The diffractive optical element 466 is disposed in the rear stage of the collimator lens 61 in a posture such that both surfaces are along the X-Y plane. The diffractive optical element 466 exerts an optical action of causing the transmitted light beam SB to branch in space, and causes diffraction light to be generated on the sub-scanning surface SS.

[0108] In the fourth embodiment described so far, the light beams SB each of which has the traveling direction adjusted by the collimator lens 61 are expanded in the light source arrangement direction Ads within the sub-scanning surface SS due to the generation action of the diffraction light of the diffractive optical element 466. Therefore, even if there is the non-light-emitting portion 23x between the plurality of laser oscillation elements 22 in the light-emitting unit 20, a gap that causes the non-detection region NDA to be generated is not easily generated between the light beams SB each of which projects light to the measurement region. Therefore, the resolution of the detection of the lidar device 400 can be improved.

[0109] In addition to this in the fourth embodiment, even if the relative position of the diffractive optical element 466 with respect to the light-emitting unit 20 is shifted along the X-Y plane, the optical action on the light beam SB is not easily changed. Therefore, the diffractive optical element 466 easily allows the positional shift on the X-Y plane. In addition, in the fourth embodiment, the diffractive optical element 466 corresponds to the "second optical element", and the lidar device 400 corresponds to the "light detection device".

[0110] (Fifth Embodiment)

[0111] Figure 10 In addition, in the fifth embodiment, the diffractive optical element 466 corresponds to the "second optical element", and the lidar device 400 corresponds to the "light detection device". Figure 11 The fifth embodiment of the present disclosure shown is another modification example of the first embodiment. The optical unit 560 of the fifth embodiment is composed of optical elements such as a first cylindrical lens 561 and a second cylindrical lens 566.

[0112] The first cylindrical lens 561 is a plano-convex cylindrical lens formed of a light-transmissive material such as synthetic quartz glass or synthetic resin. The first cylindrical lens 561 is formed with an entrance plane 562 and a convex cylindrical lens exit plane 563. The entrance plane 562 is a smooth planar surface that is substantially orthogonal to the beam optical axis BLA. The convex cylindrical lens exit plane 563 is a spherical or aspherical partial cylindrical surface that is convexly curved in the Z direction toward the exit side in the main scanning plane MS. The convex cylindrical lens exit plane 563 has positive power in the direction of transmission (Z direction) of the light beam SB.

[0113] The first cylindrical lens 561 is disposed on the optical path of the light beam SB such that the beam optical axis BLA passes through the optical center of each of the entrance plane 562 and the convex cylindrical lens exit plane 563. The first cylindrical lens 561 is disposed on the beam optical axis BLA such that the generatrix direction (non-power direction) of the convex cylindrical lens exit plane 563 is along the light source arrangement direction Ads. The first cylindrical lens 561 functions to refract each light beam SB in the main scanning plane MS and functions as a collimator to generate parallel light along the beam optical axis BLA.

[0114] The second cylindrical lens 566 is a plano-concave cylindrical lens formed of a light-transmissive material such as synthetic quartz glass or synthetic resin. The second cylindrical lens 566 is disposed at a position farther from the first cylindrical lens 561 in the rear stage of the first cylindrical lens 561. The second cylindrical lens 566 is formed with a concave cylindrical lens entrance plane 565 and an exit plane 567. The concave cylindrical lens entrance plane 565 is a spherical or aspherical partial cylindrical surface that is concavely curved in the sub-scanning plane SS toward the entrance side. The concave cylindrical lens entrance plane 565 has negative power in the direction of transmission (Z direction) of the light beam SB. The exit plane 567 is a smooth planar surface that is substantially orthogonal to the beam optical axis BLA.

[0115] The second cylindrical lens 566 is disposed on the optical path of the light beam SB such that the beam optical axis BLA passes through the optical center of each of the concave cylindrical lens entrance plane 565 and the exit plane 567. The second cylindrical lens 566 is disposed on the beam optical axis BLA such that the direction orthogonal to the generatrix of the concave cylindrical lens entrance plane 565 (power direction) is along the light source arrangement direction Ads. The second cylindrical lens 566 functions to refract each light beam SB in the sub-scanning plane SS and stretch each light beam SB in the light source arrangement direction Ads to form a linear projection light beam PB.

[0116] In the optical unit 560 described above, in the sub-scanning surface SS (Y-Z plane), the synthetic focal plane (slow-axis focal plane) FPB based on the first cylindrical lens 561 and the second cylindrical lens 566 is defined on the emission side (Z direction) with respect to the second cylindrical lens 566. On the other hand, in the main-scanning surface MS (Z-X plane), the synthetic focal plane (fast-axis focal plane) FPF based on each of the cylindrical lenses 561, 566 is defined on the emission side (-Z direction) with respect to the first cylindrical lens 561, and the synthetic focal plane coincides with the light-emitting region 21.

[0117] Further, in the first cylindrical lens 561 and the second cylindrical lens 566, the convex cylindrical lens emission surface 563 and the concave cylindrical lens emission surface 565 can be formed in a spherical shape or an aspherical shape. In addition to this, the first cylindrical lens 561 can also be a plano-convex cylindrical lens having a cylindrical lens surface that is convexly curved toward the emission side. Similarly, the second cylindrical lens 566 can also be a plano-concave cylindrical lens having a cylindrical lens surface that is concavely curved toward the emission side. Furthermore, the first cylindrical lens 561 and the second cylindrical lens 566 can also be cylindrical lenses having curvatures on both the emission surface and the emission surface.

[0118] In the laser radar device 500 of the fifth embodiment described so far, the same effects as those of the first embodiment are also obtained, and the traveling directions of each light beam SB emitted from the plurality of laser oscillation elements 22 arranged in the specific light source arrangement direction Ads are adjusted on the convex cylindrical lens emission surface 563. Furthermore, each light beam SB is expanded in the sub-scanning surface SS toward the light source arrangement direction Ads due to the negative optical power of the concave cylindrical lens emission surface 565. Therefore, even if there is a non-light-emitting portion 23x between the plurality of laser oscillation elements 22 in the light-emitting unit 20, a gap that causes a non-detection region is not easily generated between each light beam SB that projects light toward the measurement region. Therefore, it is possible to improve the resolution of the detection of the laser radar device 500.

[0119] Further, in the fifth embodiment, the first cylindrical lens 561 corresponds to the "first optical element", the convex cylindrical lens emission surface 563 corresponds to the "first cylindrical lens surface", and the concave cylindrical lens emission surface 565 corresponds to the "second cylindrical lens surface". Furthermore, the second cylindrical lens 566 corresponds to the "second optical element", and the laser radar device 500 corresponds to the "light detection device".

[0120] (Sixth Embodiment)

[0121] Figure 12 The sixth embodiment of the present disclosure shown is a modification of the fifth embodiment. The optical unit 560 of the sixth embodiment is composed of optical elements such as a first cylindrical lens 561 and a second cylindrical lens 666.

[0122] The second cylindrical lens 666 is a plano-convex cylindrical lens formed of a light-transmitting material such as synthetic quartz glass or synthetic resin. The second cylindrical lens 666 is the same as the incident surface 565 of the concave cylindrical lens in the fifth embodiment (see reference). Figure 10 The corresponding optical element is located after the first cylindrical lens 561. The second cylindrical lens 666 has an entrance plane 665 and a convex cylindrical lens exit surface 667. The entrance plane 665 is a smooth plane, substantially orthogonal to the optical axis BLA of the beam. The convex cylindrical lens exit surface 667 is a partially cylindrical surface that is either spherical or aspherical, forming a shape that is convexly curved towards the exit side from the sub-scanning plane SS. The convex cylindrical lens exit surface 667 can be formed either spherically or aspherically. The convex cylindrical lens exit surface 667 has positive optical power in the transmission direction (Z direction) of the beam SB.

[0123] The second cylindrical lens 666 is positioned on the optical path of the beam SB such that the beam optical axis BLA passes through the optical centers of the incident plane 665 and the exit surface 667 of the convex cylindrical lens. The second cylindrical lens 666 is positioned on the beam optical axis BLA in an orientation perpendicular to the generatrix of the exit surface 667 (optical power direction) along the light source arrangement direction Ads. The second cylindrical lens 666 functions to refract the beams SB within the sub-scanning plane SS, stretching the beams SB along the light source arrangement direction Ads to form a linear projected beam PB.

[0124] Based on the above optical configuration, a composite focal plane (slow-axis focal plane) FPF based on the first cylindrical lens 561 and the second cylindrical lens 666 is defined on the incident side (-Z direction) compared to the first cylindrical lens 561. The light-emitting region 21 is located at a position far away from the first cylindrical lens 561 compared to the composite focal plane FPF.

[0125] In the sixth embodiment described up to this point, the same effect as in the fifth embodiment is achieved: by forming a continuous linear projection beam PB, the detection resolution can be improved. Furthermore, in the sixth embodiment, the convex cylindrical lens exit surface 667 corresponds to the "second cylindrical lens surface," and the second cylindrical lens 666 corresponds to the "second optical element."

[0126] (Seventh Implementation)

[0127] Figure 13 as well as Figure 14 The seventh embodiment of this disclosure shown is another variation of the first embodiment. The optical unit 760 of the seventh embodiment is configured to include a homogenizer 80 and a collimating lens 761, etc.

[0128] The homogenizer 80 is located between the light emitting unit 20 and the collimator lens 761, and functions to make the intensity of each light beam SB radiated from the plurality of laser oscillation elements 22 uniform at least in the light source arrangement direction Ads. The homogenizer 80 is configured to include a first cylindrical lens 81, a second cylindrical lens 84, and a lens 87 having a positive focal power, and the like optical elements. Each optical element constituting the homogenizer 80 can have a spherical lens surface or a non-spherical lens surface.

[0129] The first cylindrical lens 81 and the second cylindrical lens 84 are substantially identical optical elements, and are optical elements in which a plurality of plano-convex lens portions are continuously arranged. The first cylindrical lens 81 and the second cylindrical lens 84 are disposed in opposition to each other in a posture in which the planar lens surfaces face each other in front of the lens 87 having a positive focal power.

[0130] The first cylindrical lens 81 has a plurality of convex entrance surface portions 82 and an exit plane 83. The convex entrance surface portions 82 are formed in a partial cylindrical shape, and are curved toward the entrance side in the sub-scanning surface SS. Each convex entrance surface portion 82 is continuously arranged in the light source arrangement direction Ads in a posture in which the focal power direction perpendicular to the generatrix is along the light source arrangement direction Ads, and forms the entrance surface of the first cylindrical lens 81. The convex entrance surface portions 82 have a positive focal power, and refract each light beam SB entering from each laser oscillation element 22 in a direction in which it converges. The exit plane 83 is a smooth planar surface, and transmits the light beams SB that have been refracted in each convex entrance surface portion 82.

[0131] The second cylindrical lens 84 is disposed in a rear stage of the first cylindrical lens 81. The second cylindrical lens 84 has an entrance plane 85 and a plurality of convex exit surface portions 86. The entrance plane 85 is a smooth planar surface, and is disposed in opposition to the exit plane 83 at a position separate from the first cylindrical lens 81. The convex exit surface portions 86 are formed in a partial cylindrical shape substantially identical to the convex entrance surface portions 82, and are curved toward the exit side in the sub-scanning surface SS. Each convex exit surface portion 86 is continuously arranged in the light source arrangement direction Ads in a posture in which the focal power direction perpendicular to the generatrix is along the light source arrangement direction Ads, and forms the exit surface of the second cylindrical lens 84. The position of each convex exit surface portion 86 in the X-Y plane substantially coincides with the position of each convex entrance surface portion 82. The convex exit surface portions 86 have a positive focal power, and further refract each light beam SB entering the entrance plane 85 in a direction in which it converges.

[0132] A lens 87 with positive optical power is disposed after the second cylindrical lens 84. The lens 87 with positive optical power has, for example, a convex entrance surface 88 and a convex exit surface 89. The lens 87 with positive optical power exerts positive optical power both within the main scanning plane MS and the sub-scanning plane SS. The lens 87 with positive optical power, located after the homogenizer 80, enables the intermediate imaging of a linear beam SB whose intensity is homogenized in the light source alignment direction ADs.

[0133] Collimating lens 761 is substantially the same as collimating lens 61 in the first embodiment (see reference). Figure 1 The same aspherical lens with positive optical power, for example, has a convex entrance surface 62 and a convex exit surface 63. A collimating lens 761 is located after the equalizer 80. The collimating lens 761 converts the beam SB transmitted through the equalizer 80 into parallel light along the beam axis BLA. The focal plane FPc on the entrance side of the collimating lens 761 is defined at the position in the equalizer 80 where the beam SB is centrally imaged. In other words, the collimating lens 761 is positioned away from the focal length at the central imaging position from the beam SB. The collimating lens 761 shapes the beam SB, which is centrally imaged through the equalizer 80, to form a projected beam PB that extends into a line.

[0134] In the lidar device 700 of the seventh embodiment described above, the same effect as in the first embodiment is achieved: the intensity of each beam SB radiated from the plurality of laser oscillating elements 22 arranged in a specific light source arrangement direction Ads is uniformized in the light source arrangement direction Ads by the homogenizer 80. Furthermore, each beam SB is shaped into a line extending in the light source arrangement direction ADs by the collimating lens 761. Therefore, even if there are un-emitting portions 23x between the plurality of laser oscillating elements 22 in the light-emitting unit 20, gaps that would cause undetected areas are less likely to occur between the beams SB projected onto the measurement area. Therefore, the detection resolution of the lidar device 700 can be improved.

[0135] In addition, as in the seventh embodiment, the homogenizer 80 uses a pair of cylindrical lenses 81 and 84, which effectively homogenizes the intensity of the beam SB. As a result, a projection beam PB can be projected, which not only eliminates the undetected area but also homogenizes the intensity overall. Therefore, the detection resolution of the lidar device 700 can be further improved.

[0136] In addition, in the seventh embodiment, the convex injection surface 82 is equivalent to the "first ejection surface", the convex ejection surface 86 is equivalent to the "second ejection surface", the collimating lens 761 is equivalent to the "shaping optical element", and the lidar device 700 is equivalent to the "light detection device".

[0137] (Eighth Implementation Method)

[0138] Figure 15 and Figure 16 The eighth embodiment of the present disclosure shown in FIG. 8 is a modification of the seventh embodiment. The homogenizer 80 of the eighth embodiment has a first convex lens array 181 and a second convex lens array 184 instead of the first cylindrical lens 81 and the second cylindrical lens 84, together with a lens 87 having a positive focal power. The first convex lens array 181 and the second convex lens array 184 are substantially identical optical elements to each other, and are optical elements in which a plurality of microlens portions are continuously two-dimensionally arranged. The first convex lens array 181 and the second convex lens array 184 are arranged in opposition to each other in a posture in which planar lens surfaces face each other in a stage preceding the lens 87 having a positive focal power.

[0139] The first convex lens array 181 has a plurality of convex entrance surface portions 182 and an exit plane 83. The convex entrance surface portions 182 are formed in a convex spherical shape, and are curved convexly toward an entrance side. The convex entrance surface portions 182 are continuously two-dimensionally arranged along the X-Y plane (the exit plane 83), and form an entrance surface of the first convex lens array 181. The convex entrance surface portions 182 have a positive focal power, and refract each light beam SB emitted from each laser oscillation element 22 in a direction in which it converges in both the main scanning plane MS and the sub-scanning plane SS. The exit plane 83 is a smooth planar surface, and transmits the light beams SB that have been refracted in the convex entrance surface portions 182.

[0140] The second convex lens array 184 is arranged in a stage succeeding the first convex lens array 181. The second convex lens array 184 has an entrance plane 85 and a plurality of convex exit surface portions 186. The entrance plane 85 is a smooth planar surface, and is arranged in opposition to the exit plane 83 at a position separate from the first convex lens array 181. The convex exit surface portions 186 are formed in a substantially identical semispherical shape to the convex entrance surface portions 182, and are curved convexly toward an exit side. The convex exit surface portions 186 are continuously two-dimensionally arranged along the X-Y plane (the entrance plane 85), and form an exit surface of the second convex lens array 184. The positions of the convex exit surface portions 186 on the X-Y plane substantially coincide with the positions of the convex entrance surface portions 182. The convex exit surface portions 186 have a positive focal power, and further refract each light beam SB that has entered the entrance plane 85 in a direction in which it converges in both the main scanning plane MS and the sub-scanning plane SS.

[0141] In the eighth embodiment described so far, the same effects as in the seventh embodiment are also obtained, and the homogenizer 80 can homogenize the intensity of the light beams SB in the light source arrangement direction Ads. As a result, the continuous linear projection light beams PB extending in the light source arrangement direction Ads are shaped, and thus high resolution of detection can be achieved.

[0142] In addition to this, as in the eighth embodiment, the intensity of the light flux SB can be effectively homogenized using the configuration of the homogenizer 80 using a pair of convex lens arrays 181, 184. As a result, the projection light flux PB in which not only the undetected region disappears but also the intensity is homogenized as a whole can be projected, so further improvement of the detection resolution can be achieved.

[0143] (Other Embodiments)

[0144] The above describes a plurality of embodiments of the present disclosure, but the present disclosure is not limited to the above-described embodiments for explanation, and can be applied to various embodiments and combinations within the scope of the gist of the present disclosure.

[0145] In Figure 17 In the lens barrel 970 of the above-described modification example 1 of the embodiment, an intermediate stop 76 is provided in addition to the field stop 73 and the opening stop 78. The intermediate stop 76 is a substantially rectangular opening formed in an intermediate member 975. The intermediate stop 76 passes the light flux SB from the convex emission surface 63 toward the incidence plane 165. The intermediate stop 76 suppresses generation of stray light inside the lens barrel 970.

[0146] In the above-described embodiment, the scanning mirror 33 common to the projection light flux PB and the reflected light flux RB is provided. The rotation axis AS of such a scanning mirror 33 can also be slightly inclined with respect to the Y axis of the optical unit 60. In addition, in the above-described modification example 2 of the embodiment, the scanning mirror that deflects the reflected light flux RB is provided independently of the scanning mirror that deflects the projection light flux PB. In addition to this, in the above-described modification example 3 of the embodiment, the scanning mirror that deflects the projection light flux SB is omitted. In the modification example 3, a plurality of laser light emission openings 25 are arranged along the X axis, and the light emission control section 51 causes each laser light emission opening 25 to radiate the light flux SB in turn. In addition, in the above-described modification example 4 of the embodiment, the scanning mirror that deflects the reflected light flux RB is further omitted. In the modification example 4, the detection section having a planar detection surface detects the reflected light flux RB in the light receiving unit.

[0147] In the above-described modification example 5 of the embodiment, the scanning mirror is not configured to perform a wobbling motion within a prescribed angle range RA, but performs a rotational motion of 360 degrees in one direction. In the scanning mirror of the modification example 5, a reflection surface is formed on both surfaces of the main body section. The scanning mirror can also be a reflection mirror such as a polygon mirror that performs two-dimensional scanning.

[0148] In Modification Examples 6 and 7 of the above-described embodiments, the beam optical axis BLA and the light-receiving optical axis RLA are not arranged in parallel. Specifically, in Modification Example 6, the interval between the beam optical axis BLA and the light-receiving optical axis RLA decreases as it approaches the reflecting surface 36 of the scanning mirror 33. On the other hand, in Modification Example 7, the interval between the beam optical axis BLA and the light-receiving optical axis RLA increases as it approaches the reflecting surface 36 of the scanning mirror 33.

[0149] The beam-shaping lens 66 of Modification Example 8 of the above-described embodiments has a positive power not only in the sub-scanning surface SS but also in the main-scanning surface MS. That is, the exit surface of the beam-shaping lens 66 has a slight curvature even in a cross section along the main-scanning surface MS. As in Modification Example 8 above, the beam-shaping lens 66 can be appropriately changed in other optical characteristics as long as it has a positive power in the sub-scanning surface SS.

[0150] In Modification Example 9 of the above-described embodiments, an arithmetic processing section corresponding to the controller 50 is provided outside the housing of the laser radar device. The arithmetic processing section can be provided as a separate in-vehicle ECU or can be installed as a functional section in a driving support ECU or an automatic driving ECU. In Modification Example 10 of the above-described embodiments, the function of the controller 50 is installed as a functional section in the detection section 41 of the light-receiving unit 40.

[0151] In Modification Example 11 of the above-described embodiments, the laser radar device is mounted on a moving body other than a vehicle. Specifically, the laser radar device can be mounted on a delivery robot or a drone that can move without a person, or the like. In Modification Example 12 of the above-described embodiments, the laser radar device is installed on a non-moving body. The laser radar device can be configured to be provided in a roadside device or the like road infrastructure and measure a measurement target such as a vehicle or a pedestrian.

[0152] The processor and the method thereof described in the present disclosure can also be implemented by a processing section of a special-purpose computer programmed to perform one or more functions embodied by a computer program. Alternatively, the processor and the method thereof described in the present disclosure can also be implemented by a special-purpose hardware logic circuit. Alternatively, the processor and the method thereof described in the present disclosure can also be implemented by discrete circuits. Alternatively, the processor and the method thereof described in the present disclosure can also be implemented by any combination of a processing section of one or more computers executing a computer program, one or more hardware logic circuits, and one or more discrete circuits. Alternatively, the computer program can be stored as instructions executed by a computer in a non-transitory tangible recording medium readable by the computer.

Claims

1. An optical detection apparatus comprising: a light emitting unit in which a plurality of light emitting portions radiating light beams are arranged at intervals in a specific arrangement direction; a scanning unit that scans the light beams radiated from the light emitting unit and performs light projection to a measurement region; a light receiving unit that receives return light of the light beams from the measurement region; and an optical unit located on an optical path of the light beams from the light emitting unit toward the scanning unit, the optical unit including: a first optical element having a positive focal power in a transmission direction of the light beams from the light emitting unit toward the scanning unit; a second optical element located at a rear stage of the first optical element and having a positive focal power in the transmission direction on a specific sectional plane extending in the transmission direction and in the specific arrangement direction; and a Fresnel lens formed by intermittently arranging divided emission surface portions curved convexly to an emission side on the specific sectional plane.

2. The optical detection apparatus according to claim 1, wherein a position of a composite focal point on an emission side of the first optical element and the second optical element is closer to the first optical element than the light emitting portions within the specific sectional plane.

3. An optical detection apparatus comprising: a light emitting unit in which a plurality of light emitting portions radiating light beams are arranged at intervals in a specific arrangement direction; a scanning unit that scans the light beams radiated from the light emitting unit and performs light projection to a measurement region; a light receiving unit that receives return light of the light beams from the measurement region; and an optical unit located on an optical path of the light beams from the light emitting unit toward the scanning unit, the optical unit including: a first optical element having a positive focal power in a transmission direction of the light beams from the light emitting unit toward the scanning unit; and a second optical element located at a rear stage of the first optical element and having a positive focal power in the transmission direction on a specific sectional plane extending in the transmission direction and in the specific arrangement direction, a position of a composite focal point on an emission side of the first optical element and the second optical element within the specific sectional plane being closer to the first optical element than a position of a composite focal point on the emission side of the first optical element and the second optical element within a normal sectional plane orthogonal to the specific sectional plane and along the transmission direction.

4. The optical detection apparatus according to claim 3, wherein the optical unit includes a cylindrical lens having an emission surface curved convexly to an emission side on the specific sectional plane as the second optical element.

5. The optical detection apparatus according to claim 3, wherein the optical unit includes a columnar lens formed by continuously arranging a plurality of emission surfaces curved convexly to an emission side on the specific sectional plane as the second optical element.

6. The optical detection apparatus according to claim 3, wherein the optical unit includes a Fresnel lens formed by intermittently arranging divided emission surface portions curved convexly to an emission side on the specific sectional plane as the second optical element.

7. The optical detection apparatus according to any one of claims 3 to 6, wherein ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ The plurality of light emitting portions are arranged in a long-side shape light emitting region with the specific arrangement direction as a long side.

8. The light detecting apparatus according to claim 7, wherein In an orthogonal cross section orthogonal to the specific cross section and along the transmission direction, the light emitting region is disposed at a position of a composite focal point on the incident side based on the first optical element and the second optical element.

9. The light detecting apparatus according to any one of claims 3 to 6, wherein The optical unit has a pre-stage diaphragm portion positioned in front of the first optical element, The pre-stage diaphragm portion forms a rectangular pre-stage opening.

10. The light detecting apparatus according to any one of claims 3 to 6, wherein The optical unit has a post-stage diaphragm portion positioned in back of the second optical element, The post-stage diaphragm portion forms a rectangular post-stage opening.

11. The light detecting apparatus according to any one of claims 3 to 6, wherein The scanning unit has a rotating mirror that rotates around a rotation axis along the specific arrangement direction.

12. A light detecting apparatus comprising: a light emitting unit in which a plurality of light emitting portions that radiate light beams are arranged at intervals in a specific arrangement direction; a scanning unit that scans the light beams radiated from the light emitting unit and performs light projection to a measurement region; a light receiving unit that receives return light of the light beams from the measurement region; and an optical unit that is positioned on an optical path of the light beams from the light emitting unit toward the scanning unit, The optical unit includes: a first optical element that forms a first cylindrical lens surface having a positive optical power in a transmission direction of the light beams from the light emitting unit toward the scanning unit, and is disposed in a posture in which a generatrix direction of the first cylindrical lens surface is along the specific arrangement direction; and a second optical element that is positioned in back of the first optical element, forms a second cylindrical lens surface having a negative optical power in the transmission direction, and is disposed in a posture in which a direction perpendicular to a generatrix of the second cylindrical lens surface is along the specific arrangement direction, a position of a composite focal point on the incident side based on the first optical element and the second optical element in a specific cross section that extends in the transmission direction and the specific arrangement direction is defined on the outgoing side of the second optical element.

13. A light detecting apparatus comprising: a light emitting unit in which a plurality of light emitting portions that radiate light beams are arranged at intervals in a specific arrangement direction; a scanning unit that scans the light beams radiated from the light emitting unit and performs light projection to a measurement region; a light receiving unit that receives return light of the light beams from the measurement region; and an optical unit that is positioned on an optical path of the light beams from the light emitting unit toward the scanning unit, The optical unit includes: a first optical element that forms a first cylindrical lens surface having a positive optical power in a transmission direction of the light beams from the light emitting unit toward the scanning unit, and is disposed in a posture in which a generatrix direction of the first cylindrical lens surface is along the specific arrangement direction; and a second optical element disposed behind the first optical element and forming a second cylindrical lens surface having a positive focal power in the transmission direction, and disposed in a posture such that a direction perpendicular to a generatrix of the second cylindrical lens surface is along the specific arrangement direction, a position of a composite focal point on an incident side based on the first optical element and the second optical element in a specific cross section extending in the transmission direction and the specific arrangement direction is closer to the first optical element than a position of a composite focal point on the incident side based on the first optical element and the second optical element in a cross section orthogonal to the specific cross section and along the transmission direction.

14. An optical detection device comprising: a light emitting unit in which a plurality of light emitting portions radiating light beams are arranged at intervals in a specific arrangement direction; a scanning unit that scans the light beams radiated from the light emitting unit and performs light projection to a measurement region; a light receiving unit that receives return light of the light beams from the measurement region; and an optical unit disposed on an optical path of the light beams from the light emitting unit toward the scanning unit, the optical unit includes: a homogenizer that makes the intensity of each of the light beams radiated from the plurality of light emitting portions uniform at least in the specific arrangement direction; and a shaping optical element disposed behind the homogenizer and shaping the light beams imaged by the homogenizer into a linear shape extending in the specific arrangement direction, the homogenizer includes: a first cylindrical lens formed by a plurality of first exit surfaces continuously arranged in the specific arrangement direction and convexly curved on a specific cross section extending in a transmission direction of the light beams and the specific arrangement direction; and a second cylindrical lens disposed behind the first cylindrical lens and formed by a plurality of second exit surfaces continuously arranged in the specific arrangement direction and convexly curved on the specific cross section.

15. An optical detection device comprising: a light emitting unit in which a plurality of light emitting portions radiating light beams are arranged at intervals in a specific arrangement direction; a scanning unit that scans the light beams radiated from the light emitting unit and performs light projection to a measurement region; a light receiving unit that receives return light of the light beams from the measurement region; and an optical unit disposed on an optical path of the light beams from the light emitting unit toward the scanning unit, the optical unit includes: a homogenizer that makes the intensity of each of the light beams radiated from the plurality of light emitting portions uniform at least in the specific arrangement direction; and a shaping optical element disposed behind the homogenizer and shaping the light beams imaged by the homogenizer into a linear shape extending in the specific arrangement direction, the homogenizer includes: a first convex lens array formed by a plurality of first exit surfaces continuously arranged two-dimensionally and convexly curved; and a second convex lens array disposed behind the first convex lens array and formed by a plurality of second exit surfaces continuously arranged two-dimensionally and convexly curved.

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