Light projector and measuring device

Abstract

The present specification discloses a technology capable of solving the abovementioned problem. The present invention confirms whether or not a light-emitting element of a light projector normally emits light. This light projector comprises: a housing having a through-path; a light-emitting element that emits light toward the through-path of the housing; and a first light projection optical system disposed in the through-path. A light introduction hole is formed on an inner wall surface of the housing defining the through-path, and the light projector has a monitoring light-receiving element that receives, via the light introduction hole, light emitted from the light-emitting element.

Description

Light projector, measuring device

[0008] ,

[0007] ,

[0001] The technology disclosed in this specification relates to a light-emitting device and a measuring device.

[0002] With the development of autonomous driving systems (AD) and advanced driver assistance systems (ADAS), research and development of LiDAR (light detection and ranging) is underway as one of the measuring devices used for grasping the surrounding environment and estimating the vehicle's own position during vehicle travel. LiDAR includes a light projector that projects laser light onto a measurement target, and a light receiver that receives the reflected light that returns after the laser light is reflected by the measurement target. LiDAR measures the distance to the measurement target based on the difference between the timing when the light projector emits laser light and the timing when the light receiver receives the reflected light. The light projector has a plurality of light-emitting devices (see, for example, Patent Document 1).

[0003] Japanese Unexamined Patent Application Publication No. 2023-117256

[0004] In conventional light projectors, devices for confirming whether a light-emitting element is emitting light normally have not been sufficiently studied.

[0005] This specification discloses a technology capable of solving the above-described problems.

[0006] The technology disclosed in this specification can be realized, for example, in the following forms.

[0007] (1) The light projector disclosed in this specification includes a housing having a through-passage, a light-emitting element that emits light toward the through-passage of the housing, and a first light projection optical system disposed in the through-passage. Among the inner wall surfaces of the housing that form the through-passage, a light introduction hole is formed, and it has a light-receiving element for monitoring that receives the light emitted from the light-emitting element through the light introduction hole. According to this light projector, the path of the light emitted from the light-emitting element and received by the light-receiving element for monitoring becomes longer due to the light introduction hole. As a result, the irradiation range of the light that can be received by the light-receiving element for monitoring expands, and the installable range of the light-receiving element for monitoring expands.

[0008] (2) The light emitter may further include a second light-emitting optical system arranged in the through-pass and between the light-emitting element and the first light-emitting optical system, wherein the light introduction hole is formed in the inner wall surface of the housing, specifically in the portion of the inner wall surface between the first light-emitting optical system and the second light-emitting optical system. With this configuration, the path of light emitted from the light-emitting element and received by the monitor light-receiving element is further lengthened by the light introduction hole arranged between the first light-emitting optical system and the second light-emitting optical system. This further widens the illumination range of light that can be received by the monitor light-receiving element, and further widens the range in which the monitor light-receiving element can be installed.

[0009] (3) In the above-mentioned light emitter, the inside of the light intake hole may be hollow. With this configuration, because the light intake hole is hollow, the path of the light emitted from the light-emitting element and received by the monitoring light-receiving element does not become focused. This makes it possible to maintain the illumination range of the light that can be received by the monitoring light-receiving element.

[0010] (4) The light source disclosed herein is a light source comprising: a housing having a through passage; a light-emitting element of the housing that emits light toward the through passage; a first light-emitting optical system disposed in the through passage; a second light-emitting optical system disposed in the through passage and between the light-emitting element and the first light-emitting optical system; and a monitor light-receiving element disposed on the inner wall surface forming the through passage that receives the light emitted from the light-emitting element. According to this light source, by arranging the monitor light-receiving element on the inner wall surface forming the through passage, the path of the light emitted from the light-emitting element and received by the monitor light-receiving element is lengthened. As a result, the irradiation range of the light that can be received by the monitor light-receiving element is widened, and the range in which the monitor light-receiving element can be installed is widened.

[0011] (5) The measuring device may be configured to include the light emitter described in any one of claims 1 to 4. With this configuration, by providing the light emitter in the measuring device, the light-receiving element for monitoring can easily and reliably detect that the light-emitting element of the measuring device is operating normally.

[0012] Furthermore, the technologies disclosed herein can be implemented in various forms, for example, in the form of floodlights, measuring devices, and the like.

[0013] Block diagram schematically showing the configuration of the measuring device in the first embodiment. Explanatory diagram showing the internal configuration of the light-emitting device in the first embodiment. Explanatory diagram showing the internal configuration of the light-emitting device in the second embodiment.

[0014] A. First Embodiment: A-1. Configuration of Measurement Device 1: This embodiment will be described with reference to Figures 1 to 3. The measurement device 1 in this embodiment is a LiDAR. The measurement device 1 is installed, for example, in a vehicle equipped with AD (automated drive) or ADAS (advanced driver assistance system). The measurement device 1 assists in the detection of objects such as people and other vehicles while the vehicle is in motion, and provides various types of information useful for ensuring the safety of the vehicle driver and those around the vehicle, and for reducing damage to objects in the surrounding area while the vehicle is in motion, to other devices and users.

[0015] As shown in Figure 1, the measuring device 1 includes a light emitter 100, a light receiver 400, an information processing device 500, and a communication interface 600.

[0016] A-1-1. Floodlight: The floodlight 100 comprises a light source unit 110 and a control circuit board 210.

[0017] (Light source unit 110): The light source unit 110 has a plurality of light-emitting units 20. The measuring device 1 of this embodiment is a FLASH-type LiDAR, and the light source unit 110 has a configuration in which, for example, a plurality of light-emitting units 20 are arranged linearly (one-dimensionally) or planarly (two-dimensionally). The configuration of the light source unit 110 will be described later.

[0018] (Control circuit board): The control circuit board 210 is a circuit board on which electronic components for controlling the light emission of the light source unit 110 are mounted. The control circuit board 210 controls the power supply circuit (not shown) of the light source unit 110 and also controls the light emission unit 20.

[0019] A-1-2. Light receiver, etc.: As shown in Figure 1, the light receiver 400 includes a light receiving optical system 410, a light receiving unit 420, and a TOF measuring device 430.

[0020] The light-receiving optical system 410 is an optical system for receiving reflected laser light Lre, which is light that has been reflected back from the measurement target W by light emitted from the light source unit 110 (for example, a light beam (laser light), hereinafter referred to as "output laser light Lout"), into the light-receiving unit 420. The light-receiving optical system 410 may be various lenses such as focusing lenses, various filters such as wavelength filters, or reflective mirrors.

[0021] The light-receiving unit 420 is equipped with a light-receiving element. The light-receiving element is, for example, a photodiode. The light-receiving unit 420 receives reflected laser light Lre incident from the light-receiving optical system 410, converts it into a received signal corresponding to the intensity and reception timing of the reflected laser light Lre, and outputs it.

[0022] The TOF measuring device 430 has, for example, a time measurement IC (integrated circuit) equipped with a TDC (time-to-digital converter) circuit. The TOF measuring device 430 is communicatively connected to the control circuit board 210 and the light receiving unit 420. The TOF measuring device 430 receives a timing signal indicating the light emission timing output from the control circuit board 210 and a light receiving signal output from the light receiving unit 420, and based on these, it determines the difference between the timing at which the output laser light Lout was emitted and the timing at which the reflected laser light Lre was received, that is, the time of flight (TOF) of the laser light. The TOF measuring device 430 outputs a signal corresponding to the determined TOF and the light receiving signal received from the light receiving unit 420.

[0023] The information processing device 500 has a processor. The processor may be, for example, a CPU (central processing unit), an MPU (microprocessing unit), an ASIC (application specific integrated circuit), an FPGA (field programmable gate array), a DSP (digital signal processor), etc. The information processing device 500 is communicatively connected to the TOF measuring device 430. The information processing device 500 receives the signal corresponding to TOF output by the TOF measuring device 430 and the received light signal, and generates various information such as the distance to the measurement target W based on these. This information may include, for example, a histogram used in time-correlated single photon counting, the distance to each point of the measurement target W, and point cloud information. The information generated by the information processing device 500 is transmitted via the communication interface 600 to an external device 700 that utilizes this information.

[0024] The external device 700 may be, for example, a device that creates an environmental map using a point cloud, or a device that performs self-localization (SLAM: Simultaneous Localization and Mapping) using scan matching algorithms such as NDT (Normal Distributions Transform) and ICP (Iterative Closest Point).

[0025] A-2. Configuration of the light source unit 110: Next, the light source unit 110 of this embodiment will be described with reference to Figure 2. The light source unit 110 of this embodiment comprises a housing 10, a light-emitting unit 20, a first light-emitting optical system 30, a second light-emitting optical system 40, a light-introducing unit 50, and a light-receiving unit 60 for monitoring.

[0026] (Housing 10): Housing 10 comprises a cylindrical side portion 11 and a bottom portion 16 with one opening of the side portion 11 closed. The cavity of the side portion 11 is hereafter referred to as the through passage 11G. The inner surface of the side portion 11 is hereafter referred to as the inner wall surface 11S. The through passage 11G is formed by the inner wall surface 11S. The material of housing 10 is metal. The inner wall surface 11S is treated to have a surface reflectivity of 0.5 to 20%. The light-emitting portion 20 is arranged on the inner surface of the bottom portion 16. Housing 10 has a first mounting portion 18 on the circumference of the opening facing the bottom portion 16. The first light projection optical system 30 is arranged on the first mounting portion 18. Housing 10 has a second mounting portion 19 in the circumferential direction on the inner wall surface 11S near the center. The second light projection optical system 40 is arranged on the second mounting portion 19. In other words, the first light projection optical system 30 and the second light projection optical system 40 are arranged on the optical path of the output laser light Lout of the through passage 11G. The first light projection optical system 30 and the second light projection optical system 40 are arranged at positions separated from each other with respect to the axial direction of the side portion 11. Light introduction holes 50h are formed in the inner wall surface 11S of the housing 10 in the radial direction of the housing 10.

[0027] (Light-emitting unit 20): The light-emitting unit 20 has a light-emitting element 22 and a first circuit board 24. The shape of the first circuit board 24 is rectangular, but it may have a shape other than rectangular (for example, circular). The light-emitting element 22 is mounted on the first circuit board 24. The light-emitting element 22 is, for example, an infrared laser light-emitting element that emits infrared light. Laser light-emitting elements include, for example, laser diodes, light-emitting diodes, surface light-emitting elements (for example, VCSEL (Vertical Cavity Surface Emitting Laser), and surface light-emitting element arrays (for example, VCSEL arrays) in which multiple surface light-emitting elements are arranged one-dimensionally or two-dimensionally on a substrate (semiconductor substrate, ceramic substrate, etc.).

[0028] (Light projection optical system): The first light projection optical system 30 and the second light projection optical system 40 (collectively referred to simply as the "light projection optical system") adjust the light distribution of the output laser light output by, for example, applying an optical effect (refraction, scattering, diffraction, etc.) to the light output laser light output output of the light emitted by each light-emitting element 22 of the light-emitting unit 20. The light projection optical system is composed of optical components such as various lenses such as collimating lenses and reflectors (mirrors).

[0029] As shown in Figure 2, the first light projection optical system 30 is a diffusion lens. The first light projection optical system 30 forms a first incident surface 32S into which the output laser light Lout is incident. The first incident surface 32S is a convex curved surface. The first incident surface 32S is directed toward the second light projection optical system. The first light projection optical system 30 forms a first exit surface 34S from which the output laser light Lout is emitted. The first incident surface 32S is a concave curved surface.

[0030] The second light projection optical system 40 is a collimating lens. The second light projection optical system 40 forms a second incident surface 42S into which the output laser light Lout is incident. The second incident surface 42S is a concave curved surface. The second light projection optical system 40 forms a second exit surface 44S from which the output laser light Lout is emitted. The second exit surface 44S is a convex curved surface. The second incident surface 42S is directed toward the light-emitting unit 20. The second exit surface 44S is directed toward the first light projection optical system 30.

[0031] (Light introduction hole 50h): The light introduction hole 50h is formed in the inner wall surface 11S (hereinafter referred to as the "second inner wall surface portion 14S") between the first light projection optical system 30 and the second light projection optical system 40. The light introduction hole 50h is circular with a diameter of 8 mm on the surface of the second inner wall surface portion 14S. The light introduction hole 50h penetrates the second side portion 14, which is the side portion 11 between the first light projection optical system 30 and the second light projection optical system 40, perpendicular to the surface of the second inner wall surface portion 14S.

[0032] (Light introduction section 50): The light introduction section 50 is a cylinder having circular openings at both ends. The circular openings of the light introduction section 50 have a diameter of 8 mm. The light introduction section 50 is located on the outside of the second side portion 14 (opposite the second inner wall surface portion 14S). The opening at one end of the light introduction section 50 on the second side portion 14 side communicates with the light introduction hole 50h. The circumference of the opening of the light introduction section 50 coincides with the circumference of the light introduction hole 50h. That is, the inner surface of the light introduction section 50 and the side surface of the second side portion 14 that forms the light introduction hole 50h form the same surface (hereinafter, this surface is referred to as the "light introduction road surface 50S"). The surface of the light introduction road surface 50S is treated so that the surface reflectivity is 0.5 to 20%. The space enclosed by the light introduction road surface 50S is the light introduction path 50G. The optical introduction path 50G extends perpendicularly from the second side portion 14 to the second inner wall portion 14S. The optical introduction path 50G is hollow.

[0033] (Monitor light receiving unit 60): The monitor light receiving unit 60 has a monitor light receiving element 62 and a second circuit board 64. The shape of the second circuit board 64 is rectangular, but it may be a shape other than rectangular (for example, circular). The monitor light receiving element 62 receives light emitted from the light source unit 110 and passing through the light introduction path 50G via the light introduction hole 50h. The monitor light receiving element 62 is a photodiode. The monitor light receiving element 62 converts the received light into a received light signal (hereinafter referred to as the "monitor light receiving signal") corresponding to the intensity of the received light and outputs it to the control circuit board 210 of the light emitter 100 (see Figure 1). The monitor light receiving element 62 is positioned on the side of the second light projection optical system 40 that is closer to the tip of the opening of the light introduction unit 50.

[0034] A-3. Operation of the light source unit 110: The operation of the light source unit 110 will be explained with reference to Figure 2. The light source unit 110 emits output laser light (Lot) from the light-emitting element 22 of the light-emitting unit 20 toward the through-passage 11G (along the axial direction of the through-passage 11G). Most of the emitted output laser light (Lot) passes through the second light projection optical system 40 and the first light projection optical system 30 and is emitted to the outside (see Figure 1). On the other hand, a portion of the output laser light (Lot) undergoes optical phenomena such as reflection, refraction, and scattering in the first light projection optical system 30 and the second light projection optical system 40, passes through the light introduction path 50G, and is received by the monitor light receiving element 62 as monitor light Ls. The monitor light Ls is received by the monitor light receiving element via the following optical path as shown in Figure 2. Note that the following optical path is just one example. - The output laser light (Ls1) is reflected externally from the first incident surface 32S of the first projection optical system 30 and passes through the optical introduction path 50G. - The output laser light (Ls2) is reflected internally from the first exit surface 34S of the first projection optical system 30 and passes through the optical introduction path 50G. - The output laser light (Ls3) is reflected internally from the first exit surface 34S of the first projection optical system 30, and the reflected light is further reflected internally from the second incident surface 42S of the second projection optical system 40 and passes through the optical introduction path 50G. - The output laser light Lout is internally reflected off the first emission surface 34S of the first light projection optical system 30, and the reflected light is further externally reflected off the second emission surface 44S of the second light projection optical system 40, passing through the optical introduction path 50G to form an optical path (Ls4). - The output laser light Lout is refracted by the second light projection optical system 40 and passes through the optical introduction path 50G to form an optical path (not shown). The monitor light Ls may be light that has followed one of the above optical paths, or light that has followed two or more optical paths.

[0035] Light passing through the light introduction path 50G via the light introduction hole 50h formed in the second inner wall portion 14S is received by the monitoring light receiving element 62 as monitor light Ls. The monitoring light receiving element 62 converts the received monitor light Ls into a monitor received signal and outputs it to the control circuit board 210 of the light emitter 100 (see Figure 1). The control circuit board 210 determines whether the level of the monitor received signal is below a certain threshold. If the level of the monitor received signal is below a certain threshold, the control circuit board 210 determines that the light-emitting element 22 is abnormal (for example, the light-emitting element 22 is not emitting output laser light Lout, or the light-emitting element 22 is not emitting output laser light Lout of the amount of light required for measurement by the measuring device 1, etc.). The control circuit board 210 outputs this result to the information processing device 500.

[0036] A-4. Effects of this embodiment: According to this embodiment, the light projector 100 can determine whether or not output laser light Lout is being emitted from the light source unit 110's light-emitting element 22 (whether or not output laser light Lout is being emitted that is sufficient for the measuring device 1 to measure the distance) without directly checking the output laser light Lout emitted from the light projector 100 or by indirectly checking the voltage or current applied to the light-emitting element 22. The output laser light Lout emitted from the light-emitting element 22 undergoes optical phenomena such as reflection, scattering, and refraction by the first light projection optical system 30 and the second light projection optical system 40, etc., and the light that passes through the light introduction path 50G is received by the monitoring light-receiving element 62 as monitor light Ls. In this way, the optical path is longer by the length of the light introduction path 50G. When the optical path is longer, the intensity of the light decreases. A range of light with an intensity corresponding to a level of the monitor reception signal above a certain threshold extends over a certain range (hereinafter referred to as the "irradiation range") on the second circuit board 64. The monitor light receiving element 62 is positioned within this irradiation range. For example, the maximum and minimum values ​​of the intensity of the monitor light Ls within the irradiation range are 100 times or less. As a result, the monitor light receiving unit 60 does not need to employ a special light receiving element (for example, a light receiving element with a wide dynamic range) or design a circuit to process a wide range of monitor reception signals.

[0037] Furthermore, when the monitoring light-receiving element 62 is placed near the light-emitting element 22 (for example, on the first circuit board 24), the monitoring light-receiving element 62 directly receives the high-intensity output laser light (Out). Because the distance between the light-emitting element 22 and the monitoring light-receiving element 62 is short, a sufficient optical path for the monitoring light Ls cannot be secured. Therefore, for such monitoring light Ls, it is necessary to use a light-receiving element with a wide dynamic range. Consequently, power consumption will also increase.

[0038] According to this embodiment, the monitor light receiving unit 60 receives monitor light Ls, which is light that has passed through the light introduction path 50G extending from the second inner wall surface portion 14S between the first light projection optical system 30 and the second light projection optical system 40. That is, the optical path of the monitor light Ls is further lengthened by optical phenomena such as reflection, refraction, and scattering between the first light projection optical system 30 and the second light projection optical system 40. In other words, the illumination range of the monitor light Ls is further widened.

[0039] According to this embodiment, the monitor light Ls is received by the monitoring light-receiving element 62 via various optical paths due to various optical phenomena in the first light-emitting optical system 30 and the second light-emitting optical system 40. In other words, the monitor light Ls is light that enters the light-introducing hole 50h from various angles and passes through the light-introducing path 50G. This means that the illumination range of the monitor light Ls is further widened.

[0040] As described above, according to this embodiment, the optical path is lengthened by the optical introduction path 50G, and the irradiation range of the monitor light Ls that has passed through the optical introduction path 50G is widened. The monitor light receiving element 62 can be placed within this irradiation range. Therefore, the monitor light receiving element 62 can be placed within a certain range. This makes it easy to install the monitor light receiving element 62 on the light emitter 100. In this embodiment, the irradiation range is, for example, 10 times or more the area of ​​the light receiving surface of the monitor light receiving element 62.

[0041] The projector 100 of the present embodiment includes a side surface portion 11 of a housing 10 having a through passage 11G, a light emitting element 22 that emits output laser light Lout toward the through passage 11G, and a first light projecting optical system 30 disposed in the through passage 11G. Among the side surface portion 11, a light introduction hole 50h is formed in an inner wall surface 11S that forms the through passage 11G, and the projector 100 has a monitor light receiving element 62 that receives the output laser light Lout emitted from the light emitting element 22 through the light introduction hole 50h. According to the projector 100, the path of the light emitted from the light emitting element 22 and received by the monitor light receiving element 62 is lengthened by the light introduction hole 50h. As a result, the irradiation range of the light that can be received by the monitor light receiving element 62 is widened, and the installable range of the monitor light receiving element 62 is widened.

[0042] The projector 100 of the present embodiment further includes a second light projecting optical system 40 that is disposed in the through passage 11G and between the light emitting element 22 and the first light projecting optical system 30, and the light introduction hole 50h may be formed in a second inner wall surface portion 14S between the first light projecting optical system 30 and the second light projecting optical system 40 of the inner wall surface 11S of the side surface portion 11. According to this configuration, the path of the light emitted from the light emitting element 22 and received by the monitor light receiving element 62 is further lengthened by the light introduction hole 50h disposed between the first light projecting optical system 30 and the second light projecting optical system 40. As a result, the irradiation range of the light that can be received by the monitor light receiving element 62 is further widened, and the installable range of the monitor light receiving element 62 is further widened.

[0043] The projector 100 of the present embodiment may be configured such that the inside of the light introduction hole 50h is hollow. According to this configuration, according to the projector 100, since the light introduction hole 50h is hollow, focusing of the path of the light emitted from the light emitting element 22 and received by the monitor light receiving element 62 does not occur. As a result, the irradiation range of the light that can be received by the monitor light receiving element 62 can be maintained.

[0044] The measuring device 1 may be configured to include the projector 100. According to this configuration, by providing the projector 100 in the measuring device 1, the monitor light receiving element 62 can easily and stably detect that the light emitting element 22 of the measuring device 1 is operating normally.

[0045] B. Second Embodiment: The second embodiment will be described while referring to FIG. 3. Note that, among the components of the measuring device 1, the second embodiment is the same as the first embodiment except for the light introduction hole 50h of the light source unit 110, the light introduction unit 50, and the light receiving unit 60 for monitoring. Therefore, in the second embodiment, these descriptions will be omitted.

[0046] B-1. Configuration of Light Source Unit 110: In the second embodiment, the light source unit 110 is arranged on the second inner wall surface portion 14S, which is the inner wall surface 11S of the housing 10 between the first light projection optical system 30 and the second light projection optical system 40, with the light receiving unit 60 for monitoring. Different from the first embodiment, the light source unit 110 of the second embodiment does not have a light introduction hole 50h or a light introduction unit 50.

[0047] B-2. Effects of this Embodiment: The light projector 100 of this embodiment includes a side surface portion 11 of the housing 10 having a through passage 11G, a light emitting element 22 that emits output laser light Lout toward the through passage 11G, a first light projection optical system 30 arranged in the through passage 11G, and a second light projection optical system 40 arranged in the through passage 11G and between the light emitting element 22 and the first light projection optical system 30. The light projector 100 further includes a light receiving element 62 for monitoring that receives the monitor light Ls emitted from the light emitting element 22 and is arranged on the second inner wall surface portion 14S that forms the second through passage portion 14G, which is the through passage 11G between the first light projection optical system 30 and the second light projection optical system 40. According to the light projector 100, by arranging the light receiving element 62 for monitoring on the first inner wall surface portion 12S that forms the first through passage portion 12G formed in the first side surface portion 12 between the light emitting portion 20 and the second light projection optical system 40, the path of the light emitted from the light emitting element 22 and received by the light receiving element 62 for monitoring becomes longer. As a result, the irradiation range of the light that can be received by the light receiving element 62 for monitoring expands, and the installable range of the light receiving element 62 for monitoring expands.

[0048] C. Variation: The technology disclosed in this specification is not limited to the above-described embodiments, and can be modified into various forms without departing from the gist thereof. For example, the following variations are also possible.

[0049] In the above embodiment, a FLASH-type LiDAR was used as an example of the measuring device 1, but it is not limited to this, and may be a scan-type LiDAR, or an optical measuring device 1 other than LiDAR. Furthermore, the measuring device 1 may have a configuration having one light-emitting unit 20. The light-emitting unit 20 may have a configuration having multiple light-emitting elements 22. In the above embodiment, the light-emitting elements 22 were infrared laser light-emitting elements that emit infrared light, but it is not limited to this, and may be light-emitting elements that emit visible light, ultraviolet light, etc.

[0050] In the above embodiment, the shape of the housing 10 is cylindrical, but it is not limited to cylindrical as long as it has a through passage 11G. The material of the housing 10 is metal, but it may be made of other materials such as resin. Also, the through passage 11G does not need to be entirely covered by the inner wall surface 11S. For example, it may only be the first inner wall surface portion 12S, which is the inner wall surface 11S that forms the first through passage portion 12G, or the second inner wall surface portion 14S.

[0051] In the above embodiment, the inner wall surface 11S of the housing 10 and the surface of the light introduction path 50S are treated to have a surface reflectivity of 0.5 to 20%, but the material is not limited to this. For example, it may be an optical system material such as a mirror.

[0052] In the above embodiment, the first light projection optical system 30 and the second light projection optical system 40 are a diffusion lens and a commat lens, respectively, but are not limited to these. Furthermore, the surface shape of each light projection optical system can be appropriately changed depending on the function of the light projection optical system.

[0053] In the above embodiment, the monitoring light Ls is received by the monitoring light receiving element 62 and the monitoring light received signal is output to the control circuit board 210 of the light emitter 100, but the embodiment is not limited to this. For example, the monitoring light receiving element 62 may output the monitoring light received signal to the information processing device 500, and the information processing device 500 may determine whether the level of the monitoring received signal is below a certain threshold. In addition, other processing devices other than the control circuit board 210 and the information processing device 500 may be newly provided.

[0054] In the above embodiment 1, the light introduction path 50G formed by the light introduction hole 50h and the light introduction section 50 is formed in the second side portion 14, but it may also be formed in the first side portion 12, which is the side portion 11 that forms the first inner wall portion 12S. The light introduction path 50G is hollow, but an optical system may be arranged therein. In that case, the optical system may be a concave lens, a convex lens, or an irregularly shaped lens. Alternatively, a rod lens or a prism may also be used. The former can increase the intensity of the monitor light Ls. The latter can widen the illumination range compared to the optical system of the former.

[0055] In the above embodiment 1, the light introduction hole 50h penetrates from the inner wall surface 11S to the side surface 11, but it does not have to penetrate. In that case, the light receiving element 62 for monitoring is placed in the light introduction hole 50h. Also, the light introduction hole 50h is formed perpendicular to the side surface 11, but it does not have to be perpendicular.

[0056] In the above embodiment 1, the light introduction section 50 is cylindrical, but its shape is not particularly limited. Also, the circumference of the opening at the base end of the light introduction section 50 and the circumference of the light introduction hole 50h coincide, but they do not have to coincide. The light introduction section 50 extends perpendicularly from the side portion 11 to the inner wall surface 11S, but it does not have to be perpendicular.

[0057] In the above embodiment 1, the monitor light receiving unit 60 was positioned at a location where the monitor light receiving element 62 receives the monitor light Ls that has passed through the light introduction path 50G, but it may also be positioned along the path of the light introduction path 50G. For example, the monitor light receiving unit 60 may be positioned in the cavity of the light introduction unit 50.

[0058] In the above embodiment 1, the light introduction hole 50h is formed in the second inner wall surface portion 14S, but it may also be formed in the first inner wall surface portion 12S, for example. Accordingly, the light introduction section 50 and the monitoring light receiving section 60 may be arranged in the first inner wall surface portion 12S. This allows the monitoring light receiving element 62 to receive, for example, light reflected from the second incident surface 42S of the second light projection optical system 40 as monitor light Ls, in addition to the monitor light Ls described above. Furthermore, the light introduction hole 50h may also be formed on the inner wall surface outside the first light projection optical system 30 (downstream of the output laser light Lout). Accordingly, the arrangement positions of the light introduction section 50 and the monitoring light receiving section 60 can be changed as appropriate. Specifically, the monitoring light receiving element 62 may be positioned so that it can receive the output laser light Lout refracted by the first light projection optical system 30 as monitor light Ls.

[0059] In the above embodiment 2, the light-receiving unit 60 for monitoring is located on the second inner wall surface portion 14S, but it may also be located on the inner wall surface outside the first light-emitting optical system 30 (downstream of the output laser light Lout). Specifically, the light-receiving element 62 for monitoring may be located in a position where it can receive the output laser light Lout refracted by the first light-emitting optical system 30 as monitor light Ls.

[0060] This international application claims priority based on Japanese Patent Application No. 2024-189611, filed on 29 October 2024, and the entire contents of said Japanese Patent Application No. 2024-189611 are incorporated herein by reference.

[0061] The above description of specific embodiments of the present invention is provided for illustrative purposes only. It is not intended to be exhaustive or to limit the invention to the forms described. Numerous modifications and changes are possible in light of the above description, as will be obvious to those skilled in the art.

[0062] 1: Measuring device 10: Housing 11: Side section 11G: Through passage 11S: Inner wall surface 12: First side section 12G: First through passage section 12S: First inner wall surface section 14: Second side section 14G: Second through passage section 14S: Second inner wall surface section 16: Bottom section 18: First mounting section 19: Second mounting section 20: Light-emitting section 22: Light-emitting element 24: First circuit board 30: First light projection optical system 32S: First incident surface 34S: First exit surface 40: Second light projection optical system 42S: Second incident surface 44S: Second exit surface 50: Light introduction section 50G: Light introduction path 50S: Light introduction path surface 50h: Light introduction hole 60: Light receiving section for monitoring 62: Light-receiving element for monitoring 64: Second circuit board 100: Light emitter 110: Light source unit 210: Control circuit board 400: Light receiver 410: Light-receiving optical system 420: Light-receiving unit 430: TOF measuring device 500: Information processing device 600: Communication interface 700: External device Output: Output laser light Lre: Reflected laser light Ls: Monitor light W: Measurement target

Claims

1. A light projector comprising: a housing having a through passage; a light-emitting element that emits light toward the through passage of the housing; and a first light-projection optical system arranged in the through passage, wherein a light-inlet hole is formed in the inner wall surface of the housing that forms the through passage, and the light projector has a monitoring light-receiving element that receives the light emitted from the light-emitting element through the light-inlet hole.

2. A floodlight according to claim 1, further comprising a second light-emitting optical system arranged in the through-passage and between the light-emitting element and the first light-emitting optical system, wherein the light introduction hole is formed in the inner wall surface of the housing, in the portion of the inner wall surface between the first light-emitting optical system and the second light-emitting optical system.

3. A floodlight according to claim 2, wherein the inside of the light introduction hole is hollow.

4. A light source comprising: a housing having a through passage; a light-emitting element of the housing that emits light toward the through passage; a first light-emitting optical system disposed in the through passage; a second light-emitting optical system disposed in the through passage and between the light-emitting element and the first light-emitting optical system; and a light-receiving element for monitoring that is disposed on the inner wall surface forming the through passage and receives the light emitted from the light-emitting element.

5. A measuring device comprising the light emitter described in any one of claims 1 to 4.

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