Lighting device and occupant monitoring device

Abstract

To irradiate a wide range with uniform illuminance.SOLUTION: A lighting device 101 includes: an LED 12 mounted on a substrate 11; a light distribution member 13 which distributes light emitted from the LED 12; and an emission surface which emits the light emitted from the LED 12 and distributed by the light distribution member 13 toward an occupant of a vehicle. The light distribution member 13 has an incident section 131 on which the light emitted from the LED 12 is incident and an emission section 132 which directs the light incident on the incident section 131 to the emission surface. The emission section 132 has a projecting shape with respect to the emission surface. The larger a deflection angle of light from a center axis X of the LED 12 is when the light is emitted from the LED 12, the smaller a refraction angle θ is when the light is emitted from the emission section 132.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to a lighting device that irradiates an occupant in a vehicle interior.

Background Art

[0002] In recent years, a driver monitoring system (DMS) that monitors the driving state of a driver by an in-vehicle camera to prevent dangerous driving or accidents has been utilized. The DMS is also called an occupant monitoring device. In the DMS, it is necessary to irradiate light onto an occupant of a vehicle and then photograph the occupant with a camera.

[0003] A lighting device that irradiates light onto an occupant includes an LED and a light distribution member that distributes light from the LED. Patent Document 1 discloses a configuration of a light distribution member in which an incident side where light from an LED is incident is composed of a cylindrical lens and a prism. According to the configuration of Patent Document 1, light with a small deflection angle from the central axis of the LED and high radiation intensity passes through the light distribution member and is irradiated onto the periphery of the occupant's face. Further, light with a large deflection angle from the central axis of the LED and low radiation intensity is totally reflected on the side surface of the light distribution member and is irradiated onto the central portion of the occupant's face.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] According to the configuration of Patent Document 1, there is a problem that the illuminance of the central portion of the occupant's face becomes high, but the illuminance of the periphery of the face becomes low, resulting in uneven illuminance.

[0006] The present disclosure has been made to solve the above problems, and an object thereof is to irradiate a wide range with uniform illuminance.

Means for Solving the Problem

[0007] The lighting device of the present disclosure is a lighting device for illuminating a vehicle occupant, and includes an LED mounted on a substrate, a light distribution member for distributing the light emitted from the LED, and an emission surface from which the light emitted from the LED and distributed by the light distribution member is emitted toward the vehicle occupant. The light distribution member includes an incident portion into which the light emitted from the LED enters, and an emission portion for guiding the light incident on the incident portion to the emission surface. The emission portion is convex with respect to the emission surface, and the larger the deflection angle from the central axis of the LED at the time of emission from the LED, the smaller the refraction angle at the time of emission from the emission portion.

Advantages of the Invention

[0008] According to the lighting device of the present disclosure, it is possible to irradiate a wide range with uniform illuminance.

Brief Description of the Drawings

[0009]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Modes for Carrying Out the Invention

[0010] <A. Embodiment 1> FIG. 1 is an exploded perspective view of a lighting device 101 according to Embodiment 1.

[0011] The lighting device 101 includes a substrate 11, at least one LED 12, a light distribution member 13, a camera 14, and a chassis 15. Although two LEDs 12 are shown in FIG. 1, the number of LEDs 12 provided in the lighting device 101 may be one or three or more. In the present embodiment, the LED 12 is an infrared LED, but it may be an LED that emits visible light. The LED 12 is mounted on the substrate 11. The light distribution member 13 is disposed at the rear stage of the LED 12 and distributes the infrared light emitted from the LED 12. The camera 14 is assembled to the chassis 15 together with the light distribution member 13 and the substrate 11. The camera 14 may be mounted on the substrate 11 on which the LED 12 is mounted. The chassis 15 is, for example, a sheet metal and is a support member for the substrate 11, the light distribution member 13, and the camera 14.

[0012] Further, the lighting device 101 includes a first resin housing 17, a second resin housing 18, and an infrared transmission resin 16. The first resin housing 17, the second resin housing 18, and the infrared transmission resin 16 are combined with each other to form the outer surface of the lighting device 101. The first resin housing 17 forms the upper surface and three side surfaces of the lighting device 101, and the second resin housing 18 forms the lower surface of the lighting device 101. The infrared transmission resin 16 forms one side surface of the lighting device 101. The first resin housing 17, the second resin housing 18, and the infrared transmission resin 16 accommodate the substrate 11, at least one LED 12, the light distribution member 13, the camera 14, and the chassis 15. The chassis 15 is overlapped with the second resin housing 18 and is exposed from the opening of the second resin housing 18. The exposed portion of the chassis 15 from the second resin housing 18 serves as an attachment portion for attaching the lighting device 101 to a vehicle.

[0013] The infrared light emitted from LED12 is distributed by the light distribution member 13 and then emitted from the infrared transmitting resin 16 to the outside of the lighting device 101 to irradiate the face of the vehicle occupant or the like. That is, the infrared transmitting resin 16 is the emission surface for emitting the infrared light of the lighting device 101. Since the infrared transmitting resin 16 blocks visible light, components such as the camera 14 cannot be seen from the outside of the lighting device 101. However, the infrared transmitting resin 16 is not an essential component of the lighting device 101. In this case, the emission surface of the lighting device 101 is defined as a virtual surface parallel to the main surface of the substrate 11 at the rear stage of the light distribution member 13.

[0014] The infrared light reflected from the face of the occupant or the like enters the interior of the lighting device 101 through the infrared transmitting resin 16 and is incident on the lens of the camera 14. Thereby, the camera 14 can image the face of the occupant or the like. In this way, the camera 14 functions as an imaging unit for imaging the vehicle occupant. Although the camera 14 is provided inside the lighting device 101 in FIG. 1, the camera 14 may be provided outside the lighting device 101.

[0015] FIG. 2 is a cross-sectional view of the lighting device 101 showing the shape of the light distribution member 13. Among the light distribution members 13, the portion where the infrared light emitted from the LED12 is incident is referred to as the incident portion 131. Further, among the light distribution members 13, the portion where the infrared light incident on the incident portion 131 is emitted toward the outside of the light distribution member 13 is referred to as the emission portion 132. That is, the emission portion 132 guides the light incident on the incident portion 131 to the emission surface.

[0016] In FIG. 2, the incident portion 131 is a Fresnel lens. By using the incident portion 131 of the light distribution member 13 as a Fresnel lens, it becomes possible to receive infrared light having a large deflection angle from the central axis X of the LED12 among the infrared light emitted from the LED12 toward the light distribution member 13.

[0017] In FIG. 2, the emission portion 132 has a shape convex toward the side of the infrared transmitting resin 16. In other words, the emission portion 132 is convex with respect to the emission surface.

[0018] The infrared light emitted from LED12 enters the light distribution member 13 at the incident portion 131, and when it exits from the light distribution member 13 at the exit portion 132, it is refracted by a refraction angle θ in the direction of the central axis X of LED12.

[0019] Incidentally, the radiation intensity of the infrared light emitted from the bullet-shaped LED12 is lower as the deflection angle from the central axis X of LED12 is larger. And according to the shape of the exit portion 132 of the light distribution member 13 shown in Fig. 2, when exiting from LED12, the larger the deflection angle of the infrared light from its central axis X, the smaller the refraction angle θ at the exit portion 132. In Fig. 2, the refraction angles θ11, θ21 of the infrared light with a large deflection angle from the central axis X of LED12 at the exit portion 132 are smaller than the refraction angles θ12, θ22 of the infrared light with a small deflection angle from the central axis X of LED12 at the exit portion 132.

[0020] Therefore, the higher the radiation intensity of the infrared light, the more it is emitted in a direction greatly inclined with respect to the central axis X of LED12 at the rear stage of the infrared transmission resin 16. Assuming a plane parallel to the main surface of the substrate 11, in the example of Fig. 2, the main surface of the infrared transmission resin 16 is the exit surface, the higher the radiation intensity of the infrared light, the larger the deflection angle from the normal direction of the exit surface when exiting from the exit surface. In other words, the lighting device 101 has a distribution in which the radiation intensity increases as the deflection angle from the normal direction of the exit surface (infrared transmission resin 16) increases.

[0021] Although Fig. 2 shows a bullet-shaped LED12, as long as the radiation intensity becomes weaker as the deflection angle from the central axis X is larger, other types of LEDs such as planar types may be used.

[0022] The infrared light incident on the upper side of the light distribution member 13 in Fig. 2 from LED12 exits from the exit portion 132 toward the lower side in Fig. 2. Also, the infrared light incident on the lower side of the light distribution member 13 in Fig. 2 from LED12 exits from the exit portion 132 toward the upper side in Fig. 2. In this way, in the lighting device 101, the infrared light exits crossing from the exit surface. Therefore, even when the LED12 is mounted at a deep position inside the housing or when the LED light is irradiated over a wide range, the scattering due to the housing or the like is suppressed.

[0023] In the example of FIG. 2, at the time of emission from the LED 12, the infrared light with the largest deflection angle from its central axis X, that is, the infrared light with the lowest emission intensity, is emitted in the normal direction of the emission surface (the infrared transmitting resin 16).

[0024] FIG. 3 shows an installation example of the lighting device 101 inside the vehicle cabin. The lighting device 101 is installed, for example, between the steering wheel and the meter display, or near the rearview mirror. For example, the lighting device 101 is installed so that the normal direction of the infrared transmitting resin 16 faces the center of the face of the occupant to be photographed by the camera 14. Thereby, infrared light with a low emission intensity can be emitted toward the center of the occupant's face, and infrared light with a higher emission intensity than that can be emitted toward the periphery of the face. Here, the periphery of the face is farther from the normal direction of the infrared transmitting resin 16 and has a longer distance from the lighting device 101 than the center of the face. And the illuminance is inversely proportional to the square of the distance from the light source. Therefore, according to the lighting device 101, it is possible to illuminate the center of the face and the periphery of the face with a uniform illuminance.

[0025] FIG. 4 is a block diagram showing the configuration of the occupant monitoring device 301 including the lighting device 101. The occupant monitoring device 301 includes the lighting device 101 and the state monitoring unit 201. The state monitoring unit 201 acquires the photographed image of the camera 14, analyzes the photographed image, and monitors whether the occupant is in a state suitable for driving the vehicle. For example, the state monitoring unit 201 detects the wakefulness of the occupant or the state of distracted driving.

[0026] Note that in FIG. 4, the lighting device 101 includes the camera 14, but the camera 14 may be provided outside the lighting device 101. Also, in FIG. 4, the state monitoring unit 201 is provided outside the lighting device 101, but it may be provided inside the lighting device 101. In this case, the lighting device 101 may be referred to as an occupant monitoring device.

[0027] FIG. 5 is a diagram showing the hardware configuration of the state monitoring unit 201. The state monitoring unit 201 is realized by the processing circuit 81 shown in FIG. 5. That is, the processing circuit 81 includes the state monitoring unit 201. For the processing circuit 81, dedicated hardware may be applied, or a processor that executes a program stored in a memory may be applied. The processor is, for example, a central processing unit, a processing device, an arithmetic device, a microprocessor, a microcomputer, a DSP (Digital Signal Processor), or the like.

[0028] When the processing circuit 81 is dedicated hardware, the processing circuit 81 corresponds to, for example, a single circuit, a composite circuit, a programmed processor, a parallel-programmed processor, an ASIC (Application Specific Integrated Circuit), an FPGA (Field-Programmable Gate Array), or a combination thereof.

[0029] When the processing circuit 81 is a processor, the functions of the state monitoring unit 201 are realized by a combination with software or the like (software, firmware, or a combination of software and firmware). The software or the like is described as a program and stored in a memory. As shown in FIG. 6, the processor 82 applied to the processing circuit 81 realizes the functions of the state monitoring unit 201 by reading and executing the program stored in the memory 83. That is, the occupant monitoring device 301 includes a memory 83 for storing a program that, when executed by the processing circuit 81, will result in the functions of the state monitoring unit 201 being executed. In other words, this program can also be said to cause a computer to execute the procedures or methods of the state monitoring unit 201. Here, the memory 83 may be, for example, a non-volatile or volatile semiconductor memory such as RAM (Random Access Memory), ROM (Read Only Memory), flash memory, EPROM (Erasable Programmable Read Only Memory), EEPROM (Electrically Erasable Programmable Read Only Memory), an HDD (Hard Disk Drive), a magnetic disk, a flexible disk, an optical disk, a compact disk, a mini disk, a DVD (Digital Versatile Disk) and its drive device, etc., or any storage medium to be used in the future.

[0030] The configuration in which the functions of the state monitoring unit 201 are realized by either hardware or software or the like has been described above. However, it is not limited to this, and a configuration in which some of the functions of the state monitoring unit 201 are realized by dedicated hardware and another part of the functions are realized by software or the like may also be possible.

[0031] Although the preferred embodiments and the like have been described in detail above, the present invention is not limited to the above-described embodiments and the like, and various modifications and substitutions can be made to the above-described embodiments and the like without departing from the scope described in the claims.

[0032] Hereinafter, aspects of the present disclosure will be collectively described as appendices.

[0033] (Appendix 1) A lighting device for illuminating an occupant of a vehicle, an LED mounted on a substrate, a light distribution member for distributing the light emitted from the LED, and an emission surface from which the light emitted from the LED and distributed by the light distribution member is emitted toward the occupant of the vehicle. The light distribution member includes an incident portion into which the light emitted from the LED enters, and an emission portion that guides the light incident on the incident portion to the emission surface. The emission portion is convex with respect to the emission surface, and the larger the deflection angle of the light from the central axis of the LED at the time of emission from the LED, the smaller the refraction angle at the time of emission from the emission portion. Lighting device.

[0034] (Appendix 2) The greater the deflection angle of the light from the central axis of the LED at the time of emission from the LED, the smaller the radiation intensity. The lighting device according to Appendix 1.

[0035] (Appendix 3) The light with the maximum deflection angle from the central axis of the LED at the time of emission from the LED is emitted from the emission surface in the normal direction thereof. The lighting device according to Appendix 1 or Appendix 2.

[0036] (Appendix 4) The light emitted from the LED is infrared light. The lighting device according to any one of Appendices 1 to 3.

[0037] (Appendix 5) The incident portion is a Fresnel lens. The lighting device according to any one of Appendices 1 to 4.

[0038] (Appendix 6) Further comprising an imaging unit mounted on the substrate for imaging an occupant of the vehicle. The lighting device according to any one of Appendices 1 to 5.

[0039] (Appendix 7) Further comprising a state monitoring unit for monitoring whether the occupant of the vehicle is in a state suitable for driving the vehicle based on an image captured by the imaging unit. The lighting device according to Appendix 6.

[0040] (Appendix 8) The lighting device according to any one of Appendices 1 to 5, An imaging unit for imaging an occupant of the vehicle irradiated with light by the lighting device, And a state monitoring unit for monitoring whether the occupant of the vehicle is in a state suitable for driving the vehicle based on an image captured by the imaging unit. Occupant monitoring device.

Explanation of Reference Signs

[0041] 11 Substrate, 12 LED, 13 Light distribution member, 14 Camera, 15 Chassis, 16 Infrared transmitting resin, 17 First resin housing, 18 Second resin housing, 81 Processing circuit, 82 Processor, 83 Memory, 101 Lighting device, 131 Incident portion, 132 Exit portion, 201 State monitoring unit, 301 Occupant monitoring device, X Central axis, θ Refraction angle.

Claims

1. A lighting device for illuminating an occupant of a vehicle, comprising: an LED mounted on a substrate; a light distribution member for distributing the light emitted from the LED; an emission surface from which the light emitted from the LED and distributed by the light distribution member is emitted toward the occupant of the vehicle. The light distribution member includes an incident portion into which the light emitted from the LED is incident, and an emission portion for guiding the light incident on the incident portion to the emission surface. The emission portion is convex with respect to the emission surface. The larger the deflection angle of the light from the central axis of the LED at the time of emission from the LED, the smaller the refraction angle at the time of emission from the emission portion. A lighting device.

2. The larger the deflection angle of the light from the central axis of the LED at the time of emission from the LED, the smaller the radiation intensity. The lighting device according to Claim 1.

3. The light having the maximum deflection angle from the central axis of the LED at the time of emission from the LED is emitted from the emission surface in the normal direction thereof. The lighting device according to Claim 1.

4. The light emitted from the LED is infrared light. The lighting device according to Claim 1.

5. The incident portion is a Fresnel lens. The lighting device according to Claim 1.

6. Further comprising an imaging unit mounted on the substrate for imaging the occupant of the vehicle. The lighting device according to Claim 1.

7. Further comprising a state monitoring unit for monitoring whether or not the occupant of the vehicle is in a state suitable for driving the vehicle based on the image captured by the imaging unit. The lighting device according to Claim 6.

8. A lighting device according to any one of Claims 1 to 5; an imaging unit for imaging the occupant of the vehicle irradiated with light by the lighting device; and a state monitoring unit for monitoring whether or not the occupant of the vehicle is in a state suitable for driving the vehicle based on the image captured by the imaging unit. An occupant monitoring device.

Images