Light-emitting devices, measuring devices

Abstract

In light-emitting devices, the red light emitted from infrared light-emitting elements is made less visible in a simpler way. [Solution] The light-emitting device comprises a first light-emitting element that emits first visible light in a first polarization state in a first direction, a second light-emitting element that emits second visible light in a second polarization state different from the first polarization state in a first direction, and a light-emitting optical system that has different refractive indices depending on the polarization state of the incident light, is positioned on the first direction side relative to the first and second light-emitting elements, and transmits the first visible light emitted by the first light-emitting element and the second visible light emitted by the second light-emitting element. The positional relationship between the first light-emitting element, the second light-emitting element and the light-emitting optical system is such that, at any position at a reference distance or more away from the light-emitting optical system in the first direction side, the entire irradiation range of the first visible light transmitted through the light-emitting optical system is included in the irradiation range of the second visible light transmitted through the light-emitting optical system, thus satisfying the condition.

Description

Technical Field

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

Background Art

[0002] In order to know the situation in front of a vehicle, a light-emitting device mounted on the vehicle and emitting infrared light is known. The light-emitting device includes an infrared light-emitting element that emits infrared light. There is a possibility that red light may be visible from the front of the light-emitting device for the infrared light emitted.

[0003] In order to make the red light visible from the front of the issuing device less noticeable, the light-emitting device may emit white light in the same direction as the direction in which the infrared light is emitted. As such a light-emitting device, a light-emitting device including an infrared light-emitting element for projecting infrared light around the vehicle, a white light-emitting element that emits white light, and a reflector formed of a transparent member having a surface on which vapor deposition is performed is known. Specifically, in the light-emitting device, either one of the infrared light-emitting element or the white light-emitting element is disposed at the focus of the reflecting surface, and the other is disposed close to the reflector so as to project light into the transparent member. And such a light-emitting device is configured to leak light inside the transparent member from at least a part of the reflecting surface (see Patent Document 1).

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] Regarding the light-emitting device that makes the red light as described above less noticeable, there is room for improvement. Such a problem is a common problem not only for light-emitting devices that emit red light but also for light-emitting devices that emit visible light that can be visually recognized.

[0006] This specification discloses a technology capable of solving the above-mentioned problems. [Means for solving the problem]

[0007] The technologies disclosed herein can be implemented, for example, in the following forms:

[0008] (1) The light-emitting device disclosed herein includes a first light-emitting element that emits first visible light in a first polarization state in a first direction, a second light-emitting element that emits second visible light in a second polarization state different from the first polarization state in the first direction, and a light-emitting optical system having different refractive indices depending on the polarization state of the incident light. The light-emitting optical system is positioned on the first direction side with respect to the first light-emitting element and the second light-emitting element, and transmits the first visible light emitted by the first light-emitting element and the second visible light emitted by the second light-emitting element. The positional relationship between the first light-emitting element, the second light-emitting element and the light-emitting optical system is such that, at any position at a reference distance or more away from the light-emitting optical system in the first direction, the entire irradiation range of the first visible light transmitted through the light-emitting optical system is included in the irradiation range of the second visible light transmitted through the light-emitting optical system, satisfying the condition. With this light-emitting device, the first visible light becomes difficult to see because the irradiation range of the first visible light is included in the irradiation range of the second visible light.

[0009] (2) In the above-described light-emitting device, the first polarization state may be circularly polarized and the second polarization state may be unpolarized, and the light-emitting optical system may be configured to convert incident circularly polarized light into parallel light and incident light other than circularly polarized light into diffuse light. With this configuration, the light-emitting optical system converts the first circularly polarized visible light into parallel light and the second unpolarized visible light into diffuse light, so that the irradiation range of the first visible light is included in the irradiation range of the second visible light.

[0010] (3) The above-mentioned light-emitting device may be configured to include a diffusion lens positioned on the first direction side, which further transmits the first visible light and the second visible light that have passed through the light-emitting optical system. With this configuration, by passing the first visible light and the second visible light that have passed through the light-emitting optical system through the diffusion lens, the illumination range of the first visible light can be included in the illumination range of the second visible light with a shorter optical path compared to a configuration without a diffusion lens.

[0011] (4) The above measuring device may be configured to include the above-mentioned light-emitting device, a light-receiving receiver, and a controller. With this configuration, when the first visible light is received by the light-receiving receiver of the measuring device, the first visible light of the measuring device becomes difficult to see.

[0012] Furthermore, the technologies disclosed herein can be implemented in various forms, for example, in the form of a light-emitting device, a measuring device, and the like. [Brief explanation of the drawing]

[0013] [Figure 1] Schematic diagram of the entire vehicle equipped with the measuring device in the embodiment. [Figure 2] Block diagram schematically showing the measuring device in the embodiment. [Figure 3] Diagram illustrating the light-emitting device in the embodiment. [Figure 4] Diagram illustrating the light emitted from the light-emitting device in the embodiment. [Figure 5] Diagram illustrating the measuring device in a comparative configuration. [Modes for carrying out the invention]

[0014] A. Embodiments: The embodiment will be described with reference to Figures 1 to 4. Figure 1 shows mutually orthogonal X, Y, and Z axes for determining direction. The positive X-axis direction is forward, and the negative X-axis direction is backward. The positive Y-axis direction is left, and the negative Y-axis direction is right. Also, the positive Z-axis direction is upward, and the negative Z-axis direction is downward.

[0015] Figure 1 is a perspective view of a vehicle 1 equipped with a measuring device 10 in an embodiment. The vehicle 1 is equipped with a pair of headlamps 70. The pair of headlamps 70 are each located on both sides in the left-right direction at the front end of the vehicle 1. Each headlamp 70 comprises a low-beam lamp unit 61, a high-beam lamp unit 62, and a measuring device 10. The low-beam lamp unit 61, the high-beam lamp unit 62, and the measuring device 10 are arranged in this order from the center side to the side side of the vehicle. The measuring device 10 in this embodiment also functions as a vehicle width lamp for the vehicle 1.

[0016] A-1. Configuration of measuring device 10: Figure 2 is a schematic block diagram showing the measuring device 10 in an embodiment. The measuring device 10 in this embodiment is a LiDAR. The measuring device 10 is installed, for example, in a vehicle equipped with an AD (automated drive) or ADAS (advanced driver assistance system). The measuring device 10 assists in detecting 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.

[0017] As shown in Figure 2, the measuring device 10 includes a light emitter 100, a light receiver 400, an information processing device 500, a communication interface 600, and a cover 50.

[0018] (Floodlight) The floodlight 100 comprises a light-emitting device 110 and a control circuit board 210. The light-emitting device 110 is a device that emits light outside the vehicle 1. The configuration of the light-emitting device 110 will be described in detail later.

[0019] The control circuit board 210 is a circuit board on which electronic components and the like for performing light emission control of the light emitting device 110 are mounted. The control circuit board 210 controls a power supply circuit (not shown) included in the light emitting device 110 and controls the infrared light emitting element 22 described later.

[0020] (Light receiver, etc.) As shown in FIG. 2, the light receiver 400 includes a light receiving optical system 410, a light receiving unit 420, and a TOF measurement device 430.

[0021] The light receiving optical system 410 is an optical system for causing the light (for example, a light beam (laser light), hereinafter referred to as "near-infrared light L1") emitted from the infrared light emitting element 22 of the light emitting device 110, which is irradiated from the vehicle 1 and reflected back by the measurement target W, to be received by the light receiving unit 420. The light receiving optical system 410 may be various lenses such as a condenser lens, may be various filters such as a wavelength filter, or may be a reflection mirror.

[0022] The light receiving unit 420 includes a light receiving element. The light receiving element is, for example, a photodiode. The light receiving unit 420 receives the reflected laser light Lre incident from the light receiving optical system 410 and converts it into a light receiving signal corresponding to the intensity and light receiving timing of the reflected laser light Lre and outputs the signal.

[0023] The cover 50 protects the light emitting device 110 and the light receiver 400 from the external environment of the vehicle 1. The cover 50 transmits the near-infrared light L1 irradiated from the light emitting device 110. The cover 50 irradiates the transmitted near-infrared light L1 to the outside of the vehicle 1 and transmits the reflected laser light Lre reflected by the measurement target W. The cover 50 is disposed in front of (in the positive X-axis direction) the light emitting device 110 and the light receiver 400. The cover 50 is, for example, a flat plate parallel to the YZ plane. The cover 50 is formed of a material that transmits the light irradiated from the light emitting device 110 and the reflected laser light Lre. The cover 50 is formed of, for example, a transparent material (for example, plastic, etc.).

[0024] 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 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 near-infrared light L1 was emitted and the timing at which 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.

[0025] 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), or a DSP (digital signal processor). 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 and the received signal from the TOF measuring device 430, 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. The information processing device 500 is a controller.

[0026] 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 estimation (SLAM: Simultaneous Localization and Mapping) using scan matching algorithms such as NDT (Normal Distributions Transform) or ICP (Iterative Closest Point).

[0027] A-2. Configuration of the light-emitting device 110: Figure 3 is an explanatory diagram of the light-emitting device 110 in an embodiment. Specifically, Figure 3 is a schematic view of the light-emitting device 110 as seen from above the vehicle 1 in the downward direction (negative Z-axis direction). The light-emitting device 110 includes a light-emitting unit 20, a light-emitting optical system 30, and a diffusion lens 40.

[0028] The light-emitting unit 20 includes an infrared light-emitting element 22, a white light-emitting element 24, and a light-emitting circuit board 26. The infrared light-emitting element 22 is an example of a first light-emitting element. The white light-emitting element 24 is an example of a second light-emitting element. The infrared light-emitting element 22 and the white light-emitting element 24 are arranged in the left-right direction relative to the vehicle 1. The infrared light-emitting element 22 and the white light-emitting element 24 are arranged on the light-emitting circuit board 26.

[0029] The infrared light-emitting element 22 emits near-infrared light L1. The near-infrared light L1 is circularly polarized (an example of a first polarization state). The wavelength of the near-infrared light is, for example, 750 nm or more and less than 1000 nm. A specific example of the wavelength of the near-infrared light L1 in this embodiment is 750 nm or more and 850 nm or less. The wavelength of the near-infrared light L1 may also be 750 nm or more and 900 nm or less. Furthermore, the wavelength of the near-infrared light L1 may also be 750 nm or more and 950 nm or less.

[0030] The white light-emitting element 24 emits white light L2. The white light L2 is unpolarized (an example of a second polarization state) and includes various polarization states. The white light L2 is visible light. The wavelength of visible light is less than 750 nm. A specific example of the wavelength of white light L2 in this embodiment is 380 nm or more and 700 nm or less. Alternatively, a specific example of the wavelength of white light L2 may be 400 nm or more and 700 nm or less. Furthermore, a specific example of the wavelength of white light L2 may be 400 nm or more and 740 nm or less. White light L2 is an example of a second visible light.

[0031] The infrared light-emitting element 22 and the white light-emitting element 24 each emit light in the same direction. The direction of the emitted light is the forward direction of the vehicle 1 (positive X-axis direction, an example of a first direction). Near-infrared light L1 has an optical axis Ax1 which is the center of the near-infrared light beam L1. White light L2 has an optical axis Ax2 which is the center of the white light beam L2.

[0032] The infrared light-emitting element 22 includes a near-infrared light source 27 and a polarizing element 28. The near-infrared light source 27 is a light source that outputs near-infrared light L1. The near-infrared light L1 output from the near-infrared light source 27 is unpolarized. The near-infrared light source 27 is, for example, a laser diode, a light-emitting diode, a surface light-emitting element (e.g., a VCSEL (Vertical Cavity Surface Emitting Laser), or a surface light-emitting element array (e.g., a VCSEL array) in which multiple surface light-emitting elements are arranged one-dimensionally or two-dimensionally on a substrate (semiconductor substrate, ceramic substrate, etc.). In this embodiment, the measuring device 10 is a FLASH-type LiDAR, and the light-emitting device 110 can also be configured by arranging, for example, multiple near-infrared light-emitting elements 27 linearly (one-dimensionally) or planarly (two-dimensionally).

[0033] The polarizing element 28 receives near-infrared light L1 emitted from the near-infrared light source 27. The polarizing element 28 is an element that converts the near-infrared light L1 emitted from the infrared light-emitting element 22 into circularly polarized light. The polarizing element 28 faces the near-infrared light source 27. The polarizing element 28 has a polarizing plate and a quarter-wave plate. The polarizing element 28 is arranged with the polarizing plate and the quarter-wave plate in that order from the side into which the near-infrared light L1 is incident. The polarizing plate converts the incident light into a wave that vibrates in a certain direction. The quarter-wave plate imparts a phase difference of λ / 4 (one-quarter of a wavelength) to the different vibrational components of the incident light.

[0034] The white light-emitting element 24 has a white light source 29. The white light source 29 emits white light L2. The white light-emitting element 24 is, for example, a light-emitting diode.

[0035] The light-emitting optical system 30 is positioned opposite the infrared light-emitting element 22 and the white light-emitting element 24 on the optical axes Ax1 and Ax2. The light-emitting optical system 30 is incident on near-infrared light L1 emitted from the infrared light-emitting element 22 and white light L2 emitted from the white light-emitting element 24. The light-emitting optical system 30 is an optical system that has different refractive indices depending on the polarization state of the incident light. In this embodiment, the light-emitting optical system 30 makes the light parallel when the incident light is circularly polarized. On the other hand, the light-emitting optical system 30 makes the light diffuse when the incident light is not circularly polarized. The light-emitting optical system 30 is, for example, a porographic element including liquid crystal. The light-emitting optical system 30 changes the refractive index of the incident light depending on the polarization state by adjusting the type of material constituting the liquid crystal and its arrangement (manetic, smectic, choletic, etc.).

[0036] The diffusion lens 40 is positioned opposite the light-emitting optical system 30 on the optical axes Ax1 and Ax2. The diffusion lens 40 receives near-infrared light L1 and white light L2 that have passed through the light-emitting optical system 30. The diffusion lens 40 diffuses the near-infrared light L1 and white light L2. For example, the emission side of the diffusion lens 40 is concave. The diffusion lens 40 is made of, for example, quartz glass.

[0037] The positional relationship between the infrared light-emitting element 22, the white light-emitting element 24, the light-emitting optical system 30, and the diffusion lens 40 is such that, in the cover 50 positioned in the forward direction of the vehicle 1 from the light-emitting device 110, the entire irradiation range Ar1 of the near-infrared light L1 emitted from the light-emitting device 110 is included in the irradiation range Ar2 of the white light L2 emitted from the light-emitting device 110 (see Figure 4).

[0038] Specifically, as shown in Figure 3, in the Y-axis direction (left-right direction of the vehicle 1) of the cover 50, the irradiation width Aw11 of the near-infrared light L1 (the width between the first near-infrared light L11 at the left end of the near-infrared light L1 and the second near-infrared light L12 at the right end of the near-infrared light L1) is inside the irradiation width Aw21 of the white light L2 (the width between the first white light L21 at the left end of the white light L2 and the second white light L22 at the right end of the white light L2) of the cover 50.

[0039] A-3. Operation of the light-emitting device 110: As shown in Figure 3, the light-emitting device 110 emits near-infrared light L1 from the near-infrared light source 27 of the light-emitting unit 20 toward the front of the vehicle 1 (positive X-axis direction). The emitted near-infrared light L1 is unpolarized diffuse light. The near-infrared light L1 emitted from the near-infrared light source 27 is converted into circularly polarized near-infrared light L1 by the polarizing element 28. The circularly polarized near-infrared light L1 is emitted from the infrared light-emitting element 22.

[0040] As shown in Figure 3, the light-emitting device 110 emits white light L2 from the white light source 29 of the light-emitting unit 20 toward the front of the vehicle 1 (positive X-axis direction). The white light L2 is unpolarized diffuse light. The white light L2 emitted from the white light source 29 is emitted from the white light-emitting element 24.

[0041] As shown in Figure 3, the near-infrared light L1, after being emitted from the infrared light-emitting element 22, diffuses to the left and right of the vehicle 1 as it moves forward (positive X-axis direction). That is, the width between the first near-infrared light L11 and the second near-infrared light L12 widens as it moves forward. The white light L2, after being emitted from the white light-emitting element 24, diffuses to the left and right of the vehicle 1 as it moves forward. That is, the width between the first white light L21 and the second white light L22 widens as it moves forward.

[0042] Near-infrared light L1 and white light L2 emitted from the light-emitting unit 20 both enter the light-emitting optical system 30. The circularly polarized near-infrared light L1 is selectively converted into parallel light by the light-emitting optical system 30, as shown in Figure 3. On the other hand, the unpolarized white light L2 is converted into diffuse light by the light-emitting optical system 30. The near-infrared light L1 that has passed through the light-emitting optical system 30 is emitted from the light-emitting optical system 30 as parallel light. On the other hand, the white light L2 that has passed through the light-emitting optical system 30 is emitted from the light-emitting optical system 30 as diffuse light.

[0043] The near-infrared light L1 and white light L2 emitted from the light-emitting optical system 30 both enter the diffusion lens 40. The near-infrared light L1 that has passed through the diffusion lens 40 is diffused again. That is, the near-infrared light L1 that has passed through the diffusion lens 40 becomes diffused light. On the other hand, the white light L2 that has passed through the diffusion lens 40 is diffused further. The near-infrared light L1 and white light L2 emitted from the diffusion lens 40 are irradiated to the outside of the vehicle 1 through the cover 50.

[0044] Figure 4 is an explanatory diagram of the light emitted from the light-emitting device 110 in the embodiment. Specifically, Figure 4 is a distribution diagram of the irradiation range of near-infrared light L1 and white light L2 irradiated from the light-emitting device 110 on the cover 50.

[0045] As shown in Figure 4, at the location of the cover 50, the entire irradiation range Ar1 of the near-infrared light L1 emitted from the light-emitting device 110 is included in the irradiation range Ar2 of the white light L2. An example of any location that is at least a reference distance away from the light-emitting optical system 30 in the front direction of the vehicle 1 is the cover 50.

[0046] The relationship between the illumination range Ar1 of near-infrared light L1 and the illumination range Ar2 of white light L2 is as shown in Figure 4 when the light-emitting device 110 is a vehicle side marker light for car 1. Specifically, at a position opposite the front of car 1 (negative X-axis direction), the white light L2 spreads in the left-right direction (Y-axis direction) of car 1 at an angle of 80° to the right and 45° to the left with respect to the optical axis Ax1. On the other hand, the near-infrared light L1 spreads at an angle of 20° to the left and right with respect to the optical axis Ax1. Furthermore, in the vertical direction toward car 1 (Z-axis direction), the white light L2 spreads at an angle of 15° up and down with respect to the optical axis Ax1. On the other hand, the near-infrared light L1 spreads at an angle of 10° to the left and right with respect to the optical axis Ax1. To achieve the relationship between the illumination range Ar1 of near-infrared light L1 and the illumination range Ar2 of white light L2 as described above, for example, the infrared light-emitting element 22 and the white light-emitting element 24 are positioned so that the direction from which the near-infrared light L1 and white light L2 are emitted is towards the front of the vehicle 1, and the emission positions of each light are positioned in the left-right direction. That is, the positions of optical axis Ax1 and optical axis Ax2 are adjusted.

[0047] A-4. Near-infrared light L1: Near-infrared light L1 is emitted from the infrared light-emitting element 22 of the light-emitting device 110. The near-infrared light L1 is irradiated in front of the car 1 (positive X-axis direction) through the cover 50. The irradiated near-infrared light L1 uses a light source intended to emit invisible infrared light during the irradiation stage. On the other hand, if the near-infrared light L1 is irradiated from the light-emitting device 110 without irradiating white light L2, it may be visible to people outside the car 1 (pedestrians, drivers of oncoming cars, etc.) as visible red light (hereinafter referred to as "red light," an example of "first visible light"). Two examples of the cause of this are as follows. The near-infrared light source 27 emits not only near-infrared light L1, but also visible light, specifically red light. When near-infrared light L1 emitted from the near-infrared light source 27 passes through optical elements (polarizing element 28, light-emitting optical system 30, diffusion lens 40, etc.) or air, a portion of the near-infrared light L1 becomes red light due to wavelength fluctuations. Therefore, the red light is visible on the cover 50.

[0048] To prevent the red light described above from being visible from outside the vehicle 1, the light-emitting device 110 emits white light L2 from the white light source 29 when it emits near-infrared light L1 from the near-infrared light source 27. Specifically, the light-emitting device 110 has a polarizing element 28, a light-emitting optical system 30, and a diffusion lens 40 as its optical system. With such a light-emitting device 110, the near-infrared light L1 and the red light are included in the white light L2 within the cover 50. That is, the entire irradiation range Ar1 of the near-infrared light L1 and red light irradiated from the light-emitting device 110 is included in the irradiation range Ar2 of the white light L2 (see Figure 4). Therefore, the red light becomes difficult to see from outside the vehicle 1.

[0049] (Comparative form) Figure 5 is an explanatory diagram of the light-emitting device 110 in a comparative form. Figure 5 is an explanatory diagram of the light-emitting device 110 in which the light-emitting optical system 30 is changed to a general collimating lens 35. The light-emitting device 110 in the comparative form is the same except that the light-emitting optical system 30 is changed to a general collimating lens 35.

[0050] In the comparative configuration of the light-emitting device 110, the collimating lens 35 converts the white light L2 into parallel light rather than diffuse light. That is, the near-infrared light L1 and white light L2 transmitted through the collimating lens 35 become parallel light between the collimating lens 35 and the diffusion lens 40. Subsequently, the near-infrared light L1 and white light L2 become diffuse light together through the diffusion lens 40. The near-infrared light L1 is irradiated to the outside of the car 1 via the cover 50. The white light L2 is irradiated to the outside of the car 1 via the cover 50. As shown in Figure 5, the irradiation width Aw12 of the near-infrared light L1 irradiated to the outside of the car 1 is not included inside the irradiation width Aw22 of the white light L2. In other words, a portion of the near-infrared light L1 leaks out from the irradiation range Ar2 of the white light L2. That is, the red light of the visible light portion of the near-infrared light L1 is visible from the front of the car 1.

[0051] A-5. Effects of this embodiment: As described above, the light-emitting device 110 of this embodiment includes an infrared light-emitting element 22 that emits near-infrared light L1 and red light, which are in a first polarization state, in front of the car, a white light-emitting element 24 that emits white light L2, which is in a second polarization state, in a first direction, and a light-emitting optical system 30 having different refractive indices depending on the polarization state of the incident light. The light-emitting optical system 30 is positioned on the first direction side relative to the infrared light-emitting element 22 and the white light-emitting element 24, and the near-infrared light L1 emitted by the infrared light-emitting element 22 and the white light L2 emitted by the white light-emitting element 24 are transmitted through it. The positional relationship between the infrared light-emitting element 22, the white light-emitting element 24 and the light-emitting optical system 30 is such that, for example, at the position of the cover 50, the entire irradiation range of the near-infrared light L1 and red light transmitted through the light-emitting optical system 30 is included in the irradiation range of the white light L2 transmitted through the light-emitting optical system 30, thus satisfying the condition. According to the light-emitting device 110 of this embodiment, the illumination range Ar1 of near-infrared light L1 and red light is included in the illumination range Ar2 of the second visible light, making the red light difficult to see. Furthermore, the near-infrared light L1 and red light become part of the various wavelengths of white light L2. Therefore, people outside the car 1 perceive it as white light, and the red light becomes invisible. In addition, the light-emitting device 110 can have a single light-emitting optical system 30. Therefore, the light-emitting device 110 does not need to have a complex structure and can be made more compact.

[0052] In the light-emitting device 110 of this embodiment, the first polarization state is circularly polarized and the second polarization state is unpolarized, and the light-emitting optical system 30 may be configured to convert incident circularly polarized light into parallel light and incident light other than circularly polarized light into diffuse light. According to the light-emitting device 110 of this embodiment, the light-emitting optical system 30 converts circularly polarized near-infrared light L1 into parallel light and unpolarized white light L2 into diffuse light, so that the irradiation range Ar1 of the near-infrared light L1 and red light is included in the irradiation range Ar2 of the second visible light.

[0053] In the light-emitting device 110 of this embodiment, a diffusion lens 40 may be provided, which is positioned in the first direction and further transmits the near-infrared light L1 and white light L2 that have passed through the light-emitting optical system 30. According to the light-emitting device 110 of this embodiment, by passing the near-infrared light L1 and white light L2 that have passed through the light-emitting optical system 30 further through the diffusion lens 40, the illumination range Ar1 of the near-infrared light L1 and red light can be included in the illumination range Ar2 of the second visible light with a shorter optical path compared to a configuration without a diffusion lens 40. In addition, the diffusion lens 40 converts the near-infrared light L1 that has passed through the light-emitting optical system 30 from parallel light to diffused light. As a result, as the intensity of the diffused white light L2 gradually weakens with distance from the car 1, the intensity of the diffused near-infrared light L1 also weakens.

[0054] In this embodiment, the system may be configured to include the light-emitting device 110, a light-receiving receiver 400, and an information processing device 500 which is a controller. With this configuration, when near-infrared light L1 is received by the light-receiving receiver 400 of the measuring device 10, the red light from the measuring device 10 becomes less visible.

[0055] B. Variations: The technologies disclosed herein are not limited to the embodiments described above and can be modified in various forms without departing from their essence, for example, the following modifications are possible. (1) In the above embodiment, a flash-type LiDAR was used as an example of the measuring device 10, but it is not limited to this, and for example, a scan-type LiDAR or an optical measuring device 10 other than LiDAR may also be used. (2) In the above embodiment, the measuring device 10 is a vehicle side marker light of the vehicle 1, but is not limited to a vehicle side marker light. For example, it may be a low beam lamp unit 61 or a high beam lamp unit 62. (3) In the above embodiment, the direction in which the light-emitting device 110 emits near-infrared light L1 and white light L2 (first direction) is the front of the vehicle 1, but it may also be the rear of the vehicle 1 or the side of the vehicle. (4) The "first light-emitting element that emits a first visible light in a first polarization state in a first direction" is not limited to an element that emits visible light (and near-infrared light L1), but may also be an element that emits only near-infrared light L1 and causes wavelength fluctuations when it passes through an optical system (polarizing element 28, light-emitting optical system 30, diffusion lens 40, etc.) or air, thereby irradiating the cover 50 with red light. (5) The white light-emitting element 24 in the above embodiment emits white light L2, but it does not have to be white light; it may emit light of a specific color. For example, it may emit orange light (for example, light with a wavelength of 590 nm or more and 630 nm or less) or green light (for example, light with a wavelength of 500 nm or more and 560 nm or less). (6) In the above embodiment, the white light source 29 is a light-emitting diode, but a halogen lamp or an incandescent light bulb may also be used. (7) In the above embodiment, the infrared light-emitting element 22 and the white light-emitting element 24 are arranged in the left-right direction relative to the vehicle 1, but are not limited to the left-right direction. For example, they may be arranged in the up-down direction or the front-back direction. Also, the infrared light-emitting element 22 and the white light-emitting element 24 are arranged on the same substrate, but they may be arranged on separate substrates. (8) In the above embodiment, the infrared light-emitting element 22 and the white light-emitting element 24 each emit light in the same direction, but on the first direction side, the near-infrared light L1 and the white light L2 emitted by each do not need to be parallel. (9) In the above embodiment, the near-infrared light L1 is circularly polarized and the white light L2 is unpolarized, but the embodiment is not limited to these, as long as the polarization state of the near-infrared light L1 and the polarization state of the white light L2 are different. For example, the near-infrared light L1 may be linearly polarized in the Y-axis direction and the white light L2 may be linearly polarized in the Z-axis direction, or vice versa. Also, when controlling the polarization state of the white light L2, the white light-emitting element 24 that emits the white light L2 may be equipped with a polarizing element 28. (10) In the above embodiment, the infrared light-emitting element 22 has a polarizing element 28, but the polarizing element 28 does not have to be arranged on the infrared light-emitting element 22. The polarizing element 28 may be arranged as a separate component on the front side of the vehicle 1, which is the first direction side of the infrared light-emitting element 22. Also, in the above embodiment, the polarizing element 28 is composed of a polarizing plate and a quarter-wave plate, but this can be changed as appropriate depending on the polarization state of the near-infrared light L1. For example, if the near-infrared light L1 is linearly polarized, the polarizing element 28 may consist only of a polarizing plate. (11) In the above embodiment, the light-emitting optical system 30 uses near-infrared light L1 as parallel light and white light L2 as diffuse light, but is not limited to this. For example, the near-infrared light L1 may be diffuse light, and the white light L2 may be diffuse light that is even more diffuse than the diffusion of the near-infrared light L1. (12) In the above embodiment, the cover 50 is positioned in front of the light-emitting device 110 and the light-receiving device 400, but it may be positioned only in front of the light-emitting device 110. In that case, a separate cover may be provided for the light-receiving device 400. Also, in the above embodiment, the cover 50 is made of a transparent material, but it may be made of other materials as long as it transmits near-infrared light L1. For example, in order to make the light emitted from the light-emitting device 110 appear orange, the material of the cover 50 may be made orange. Also, although the cover 50 has a shape that extends across the YZ plane of the vehicle 1, it does not have to be a flat surface, but may be a curved surface. (13) In the above embodiment, the entire irradiation range Ar1 of the near-infrared light L1 and red light irradiated from the light-emitting device 110 is included in the irradiation range Ar2 of the white light L2 irradiated from the light-emitting device 110. However, the location for determining whether the entire irradiation range Ar1 of the near-infrared light L1 and red light is included in the irradiation range Ar2 of the white light L2 does not have to be the cover 50. It is sufficient to be at least a certain distance away from the direction in which the near-infrared light L1 and white light L2 are irradiated from the light-emitting device 110 (in front of the car 1). Specifically, it may be 10m away from the car 1 (or cover 50) or 30m away. (14) In the above embodiment, the light-emitting device 110 is a component of the measuring device 10, but the light-emitting device 110 can be used for purposes other than measuring devices. For example, the light-emitting device 110 can also be used as a device for improving the sensitivity of an image sensor. In addition, the light-emitting device 110 can be used in a system for detecting the relative positions of vehicles by mounting a light receiver in a vehicle other than vehicle 1. [Explanation of symbols]

[0056] 1: Car 10: Measuring device 20: Light-emitting unit 22: Infrared light-emitting element 24: White light-emitting element 26: Light-emitting circuit board 27: Near-infrared light source 28: Polarizing element 29: White light source 30: Light-emitting optical system 35: Collimating lens 40: Diffusing lens 50: Cover 61: Low-beam lamp unit 62: High-beam lamp unit 70: Headlamp 100: Floodlight 110: Light-emitting device 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 L11: First near-infrared light L12: Second near-infrared light L1: Near-infrared light L21: First white light L22: Second white light L2: White light Lre: Reflected laser light W: Measurement target

Claims

1. A light-emitting device, A first light-emitting element emits a first visible light, which is a first polarization state, in a first direction. A second light-emitting element emits a second visible light, which has a second polarization state different from the first polarization state, in the first direction. A light-emitting optical system having different refractive indices depending on the deflection state of incident light, comprising: a light-emitting optical system arranged on the first direction side with respect to the first light-emitting element and the second light-emitting element, through which the first visible light emitted from the first light-emitting element and the second visible light emitted from the second light-emitting element are transmitted; The positional relationship between the first light-emitting element, the second light-emitting element, and the light-emitting optical system is such that, at any position at a reference distance or greater from the light-emitting optical system in the first direction, the entire irradiation range of the first visible light transmitted through the light-emitting optical system is included in the irradiation range of the second visible light transmitted through the light-emitting optical system, satisfying the conditions. Light-emitting device.

2. A light-emitting device according to claim 1, The first polarization state is circularly polarized, and the second polarization state is unpolarized. The aforementioned light-emitting optical system treats incident circularly polarized light as parallel light and incident light other than circularly polarized light as diffuse light. Light-emitting device.

3. A light-emitting device according to claim 2, The optical system includes a diffusing lens positioned on the first direction side, which further transmits the first visible light and the second visible light that have passed through the light-emitting optical system. Light-emitting device.

4. A measuring device comprising a light-emitting device according to any one of claims 1 to 3, a light-receiving device, and a controller.

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