Vehicle lighting system, light distribution control device, and light distribution control method

Abstract

This vehicle light fixture system comprises: a low beam unit that is capable of forming a low-beam light distribution pattern (P5) having a cutoff line (CL) and that enables, in the low-beam light distribution pattern (P5), mutually independent adjustment of the illuminance of a plurality of partial areas (P3) that are below the cutoff line (CL) and aligned along the cutoff line (CL); and a light distribution control device that controls the low beam unit so as to form a first illuminance reduction section (46) in a partial area (P3), from among the plurality of partial areas (P3), for which the position thereof in the vehicle-width direction overlaps the position of a front vehicle (100) in the vehicle-width direction.

Description

[Technical Field]

[0001] The present invention relates to a vehicle lighting system, a light distribution control device, and a light distribution control method. [Background technology]

[0002] Vehicle lighting fixtures play an important role in ensuring safe driving at night and in tunnels. Prioritizing driver visibility by illuminating a wide area in front of the vehicle brightly can cause glare to drivers of preceding and oncoming vehicles. In response to this issue, conventional vehicle lighting fixtures reduce glare to drivers of preceding vehicles by forming a low-beam light distribution pattern that includes a cutoff line (see, for example, Patent Document 1).

[0003] Also, ADB (Adaptive Driving Beam) control has been proposed, which dynamically and adaptively controls the high beam distribution pattern based on the surrounding conditions of the vehicle. The system uses a camera or other device to detect the presence or absence of a vehicle ahead and dims or turns off the lights in the area corresponding to the vehicle ahead. By changing the high beam light distribution according to the position of the vehicle ahead, it is possible to reduce glare for the driver of the vehicle ahead and improve visibility for the driver of the vehicle. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2012-134091 Summary of the Invention [Problem to be solved by the invention]

[0005] The present inventors have conducted extensive research into light distribution control of vehicle lamps and have come to realize that there is room for reducing the glare that a driver of a vehicle ahead experiences with conventional light distribution control.

[0006] The present invention has been made in view of the above circumstances, and one of its objects is to provide a technique for reducing the glare given to the driver of a vehicle ahead. [Means for solving the problem]

[0007] One aspect of the present invention is a vehicle lighting system that includes a low beam unit that can form a low beam light distribution pattern having a cutoff line and that can independently adjust the illuminance of a plurality of partial regions that are aligned below and along the cutoff line in the low beam light distribution pattern, and a light distribution control device that controls the low beam unit to form a first illuminance reduction portion in a partial region that, in a vehicle width direction, overlaps with the position of a forward vehicle in the vehicle width direction.

[0008] Another aspect of the present invention is a light distribution control device that controls a low beam unit that can form a low beam light distribution pattern having a cutoff line and can independently adjust the illuminance of multiple partial regions that are aligned below and along the cutoff line in the low beam light distribution pattern. This light distribution control device controls the low beam unit to form a first illuminance reduction portion in a partial region, among the multiple partial regions, whose position in the vehicle width direction overlaps with the position of a forward vehicle in the vehicle width direction.

[0009] Another aspect of the present invention is a light distribution control method for controlling formation of a low-beam light distribution pattern having a cutoff line, the light distribution control method including forming a first illuminance reduction portion in a partial region of the low-beam light distribution pattern that is aligned below and along the cutoff line and whose position in the vehicle width direction overlaps with the position of a forward vehicle in the vehicle width direction.

[0010] Any combination of the above components and conversion of the present invention into a method, device, system, etc. are also valid aspects of the present invention. [Effects of the Invention]

[0011] According to the present invention, it is possible to reduce the glare given to the driver of the vehicle ahead. [Brief explanation of the drawings]

[0012] [Figure 1] 1 is a diagram showing a schematic configuration of a vehicle lighting system according to an embodiment; [Figure 2] Fig. 2(a) is a schematic diagram showing the ranges in which the low beam unit and the ADB unit can irradiate light, and Fig. 2(b) is a schematic diagram showing the low beam light distribution pattern and the ADB light distribution pattern. [Figure 3] 10A and 10B are schematic diagrams showing a light distribution pattern formed when a forward vehicle is detected; [Figure 4] 4 is a schematic diagram for explaining a method of setting the illuminance of a first illuminance reducing unit. FIG. [Figure 5] 4 is a flowchart showing an example of light distribution control executed by a light distribution control device. DETAILED DESCRIPTION OF THE INVENTION

[0013] The present invention will be described below with reference to the drawings based on preferred embodiments. The embodiments are illustrative and do not limit the invention, and all features and combinations thereof described in the embodiments are not necessarily essential to the invention. Identical or equivalent components, parts, and processes shown in each drawing are designated by the same reference numerals, and redundant description will be omitted where appropriate. The scale and shape of each part shown in each drawing are set for convenience to facilitate explanation and should not be interpreted as limiting unless otherwise specified. Furthermore, when terms such as "first" and "second" are used in this specification or claims, unless otherwise specified, these terms do not indicate any order or importance, but are used to distinguish one configuration from another. Furthermore, some components that are not important for explaining the embodiments are omitted from each drawing.

[0014] Fig. 1 is a diagram showing a schematic configuration of a vehicle lighting system 1 according to an embodiment. In Fig. 1, some of the components of the vehicle lighting system 1 are depicted as functional blocks. These functional blocks are realized as a hardware configuration by elements and circuits such as a computer CPU and memory, and as a software configuration by a computer program or the like. Those skilled in the art will understand that these functional blocks can be realized in various ways by combining hardware and software.

[0015] The vehicle lighting system 1 includes a low beam unit 2, an ADB unit 4, a vehicle detection device 6, and a light distribution control device 8. The vehicle lighting system 1 of this embodiment also includes a lamp body 10 having an opening on the front side of the vehicle, and a translucent cover 12 attached to cover the opening of the lamp body 10. The lamp body 10 and the translucent cover 12 form a lamp chamber. The low beam unit 2, the ADB unit 4, the vehicle detection device 6, and the light distribution control device 8 are housed in the lamp chamber. The vehicle detection device 6 and the light distribution control device 8 may be provided outside the lamp chamber, for example, on the vehicle side. For example, the vehicle detection device 6 may be configured as an on-board camera. The light distribution control device 8 may be configured as a vehicle ECU. The low beam unit 2 and the ADB unit 4 may also be housed in separate lamp chambers.

[0016] The low beam unit 2 includes a first irradiation section 14 and a second irradiation section 16. The first irradiation section 14 and the second irradiation section 16 are fixed to the lamp body 10 by a known connecting mechanism (not shown) in a state in which the optical axes of the respective irradiation sections can be adjusted in the horizontal and vertical directions.

[0017] The first irradiating section 14 of this embodiment is a so-called projector type (diffusion lens optical system) lighting unit, and has a first light source 18, a first heat sink 20, a reflector 22, a lens holder 24, and a first projection lens 26.

[0018] The first light source 18 has a structure in which a light-emitting element 18b is arranged on a circuit board 18a. The circuit board 18a is a thermally conductive insulating substrate made of ceramic or the like. Electrodes for transmitting power to the light-emitting element 18b are formed on the circuit board 18a. The light-emitting element 18b is, for example, an LED (light-emitting diode). Note that the light-emitting element 18b may be a semiconductor light-emitting element other than an LED, such as an LD (laser diode) or an organic or inorganic EL (electroluminescence). The first light source 18 may also be an incandescent lamp, a halogen lamp, a discharge lamp, or the like. The first light source 18 is mounted on a first heat sink 20.

[0019] The first heat sink 20 is a heat dissipation member that dissipates heat from the first light source 18. The first heat sink 20 has a flat surface 20a, and the first light source 18 is mounted on the flat surface 20a. A reflector 22 is also mounted on the flat surface 20a. The reflector 22 has a reflective surface 22a. The reflective surface 22a is configured, for example, as a part of a paraboloid of revolution. The positional relationship of the reflector 22 with the first light source 18 is determined so that the light emitting element 18b is located near the focal point of the reflective surface 22a. The first heat sink 20 has a protrusion 20b that protrudes toward the front of the lamp. The tip of the protrusion 20b abuts against the outer periphery of the first projection lens 26 to support the first projection lens 26.

[0020] Furthermore, a lens holder 24 is connected to the protrusion 20b. The lens holder 24 abuts against a portion of the outer periphery of the first projection lens 26 that is not connected to the protrusion 20b, thereby supporting the first projection lens 26. The entire outer periphery of the first projection lens 26 is surrounded by the protrusion 20b and the lens holder 24, and the first projection lens 26 is fixed on the optical axis of the first illumination unit 14. The first projection lens 26 is an optical member that illuminates light from the first light source 18 forward of the lamp while diffusing the light in the vehicle width direction (horizontal direction). As an example, the first projection lens 26 is a cylindrical lens with a convex front surface and a flat rear surface, and with a focal line extending horizontally.

[0021] The light emitted from the first light source 18 is reflected by the reflecting surface 22a of the reflector 22 toward the first projection lens 26. The light reflected by the reflecting surface 22a enters the first projection lens 26 and is diffused in the vehicle width direction by the first projection lens 26 while being irradiated onto the area ahead.

[0022] The second irradiator 16 is configured with a variable light distribution lamp that can irradiate a visible light beam L1 with a variable intensity distribution toward the area ahead of the vehicle. The second irradiator 16 of this embodiment has a light source array 27. The light source array 27 includes a plurality of light sources 27a arranged in a matrix and a circuit board 27b that turns on and off each light source 27a independently. Preferred examples of the light source 27a include semiconductor light-emitting elements such as LEDs, LDs, and organic or inorganic ELs.

[0023] The ADB unit 4 is fixed to the lamp body 10 by a known connecting mechanism (not shown) in a state in which the optical axis can be adjusted in the horizontal and vertical directions. The ADB unit 4 is composed of a variable light distribution lamp that can irradiate a visible light beam L2 with a variable intensity distribution toward the area in front of the vehicle. The ADB unit 4 of this embodiment is a so-called scanning optical type lamp unit, and has a second light source 28, a condensing lens 30, a rotating reflector 32, a second projection lens 34, a second heat sink 36, and a drive mechanism 38.

[0024] The second light source 28 has a structure in which a plurality of light-emitting elements 28b are arranged on a circuit board 28a. Each light-emitting element 28b is configured to be able to be turned on and off individually. The light-emitting elements 28b may be semiconductor light-emitting elements such as LEDs, LDs, organic or inorganic ELs. The second light source 28 may also be an incandescent bulb, a halogen lamp, a discharge bulb, or the like. The condensing lens 30 is an optical member that changes the optical path of the light emitted from the second light source 28 and directs the light toward the blades 32a of the rotating reflector 32.

[0025] The rotating reflector 32 is an optical element that rotates around a rotation axis R while reflecting light emitted from the second light source 28. The rotating reflector 32 has multiple blades 32a, a rotating cylinder 32b, and a motor 32c as a drive source. The multiple blades 32a function as a light reflecting surface and are fixed to the circumferential surface of the rotating cylinder 32b. The rotating cylinder 32b is oriented so that the central axis of the cylinder coincides with the output shaft of the motor 32c, and is fixed to the output shaft of the motor 32c. The output shaft of the motor 32c and the central axis of the rotating cylinder 32b coincide with the rotation axis R of the rotating reflector 32. When the motor 32c is driven, the blades 32a rotate in one direction around the rotation axis R. As the blades 32a rotate, they reflect light from the second light source 28, scanning the area in front of the lamp with light.

[0026] The second projection lens 34 is an optical element that projects the light reflected by the rotating reflector 32 forward of the lamp. The second projection lens 34 is made of, for example, a plano-convex aspherical lens. The second projection lens 34 of this embodiment has a notch 34a on part of its outer periphery. The presence of the notch 34a makes it less likely that the blades 32a of the rotating reflector 32 will interfere with the second projection lens 34, allowing the second projection lens 34 and the rotating reflector 32 to be closer together.

[0027] The second heat sink 36 is a heat dissipation member that dissipates heat from the second light source 28. The second heat sink 36 is disposed on the opposite side of the second light source 28 from the rotating reflector 32. The second light source 28 is fixed to the surface of the second heat sink 36 that faces the rotating reflector 32.

[0028] The ADB unit 4 has a lamp bracket 40. Each component of the ADB unit 4 is supported by the lamp body 10 via the lamp bracket 40. The lamp bracket 40 is, for example, a plate-like component arranged with its main surface facing the front-to-rear direction of the lamp fixture, and a second heat sink 36 is fixed to the main surface facing the front side of the lamp fixture. The second light source 28 is fixed to the lamp bracket 40 via the second heat sink 36. The rotating reflector 32 is fixed to the lamp bracket 40 via a base 42. The second projection lens 34 is fixed to the lamp bracket 40 via a lens holder (not shown).

[0029] A drive mechanism 38 is connected to the main surface of the lamp bracket 40 facing the rear of the lamp. The drive mechanism 38 is configured, for example, by a leveling actuator. The drive mechanism 38 has a rod 38a and a motor that extends and retracts the rod 38a in the fore-and-aft direction of the lamp. The tip of the rod 38a is fixed to the lamp bracket 40. The ADB unit 4 assumes a rearward tilt position when the rod 38a extends. The ADB unit 4 assumes a forward tilt position when the rod 38a contracts. Therefore, the pitch angle of the optical axis of the ADB unit 4 can be leveled by driving the drive mechanism 38.

[0030] The structures of the low beam unit 2 and the ADB unit 4 are merely examples and are not limited to those described above. For example, the first irradiator 14 may be a so-called reflective (parabolic optical system) lamp unit. That is, the first irradiator 14 may have a reflector instead of the first projection lens 26 as an optical member that diffuses the light of the first light source 18 in the vehicle width direction. The reflector has a reflective surface formed of, for example, a parabolic cylindrical surface, and is arranged so that the light emitting element 18b is located near the focal point of the reflective surface, and is fixed to the first heat sink 20.

[0031] The second irradiation unit 16 is a matrix such as a DMD (Digital Mirror Device) or a liquid crystal device. The ADB unit 4 may be a light source array, a matrix type pattern forming device, or the like. The low beam unit 2 and the ADB unit 4 may be integrated into one unit.

[0032] The vehicle detection device 6 detects vehicles ahead that are present in the area ahead of the vehicle itself. Forward vehicles include preceding vehicles and oncoming vehicles. The vehicle detection device 6 of this embodiment has an imaging device 43 as a means for detecting forward vehicles. The imaging device 43 has sensitivity in the visible light range and captures an image of the area ahead to generate an image IMG. The vehicle detection device 6 sends the image IMG generated by the imaging device 43 to the light distribution control device 8 as a detection result.

[0033] The vehicle detection device 6 may also include other detection means, such as a distance measurement sensor. The distance measurement sensor is directed toward the area ahead and acquires information about the area ahead. The distance measurement sensor may be configured, for example, with a millimeter-wave radar or LiDAR (Light Detection and Ranging or Laser Imaging Detection and Ranging). The distance measurement sensor can acquire the presence of a vehicle ahead and the distance to the vehicle ahead, which are associated with the reflected wave or light, based on the time from when millimeter waves or light are emitted toward the area ahead to when the reflected wave or light is detected. Furthermore, by accumulating such distance data in association with the detected position of the vehicle ahead, information about the movement of the vehicle ahead can be acquired.

[0034] The light distribution control device 8 controls the formation of a light distribution pattern by the low beam unit 2 and the ADB unit 4 based on the detection result of the vehicle detection device 6. The light distribution control device 8 can be configured with a digital processor, and may be configured, for example, by a combination of a microcomputer including a CPU and a software program, or may be configured with a FPGA (Field Programmable Gate Array) or A It may be configured as an SIC (Application Specific IC), etc. The light distribution control device 8 operates when the integrated circuit that configures it executes a program stored in a memory.

[0035] The shape of the light distribution pattern formed by each lamp unit and the control of the formation of the light distribution pattern by the light distribution control device 8 will be described below. FIG. 2(a) is a schematic diagram showing the ranges over which the low beam unit 2 and the ADB unit 4 can emit light. FIG. 2(b) is a schematic diagram showing a low beam light distribution pattern P5 and an ADB light distribution pattern P6. FIG. 3 is a schematic diagram showing a light distribution pattern formed when a forward vehicle is detected. Note that the relative positional relationship between each light irradiation range may deviate from the state shown in FIG. 2(a). Similarly, the relative positional relationship between each light distribution pattern may deviate from the state shown in FIG. 2(b) and FIG. 3. Furthermore, the light distribution pattern is understood to be a two-dimensional illuminance distribution of the irradiation pattern formed by each unit on a virtual vertical screen in front of the vehicle.

[0036] 2(a) and 2(b) by emitting light from the first light source 18. The diffusion pattern P1 is a pattern that extends below the H line at a pitch angle of 0° and beyond a cutoff line CL (described later) in the vehicle width direction.

[0037] The second irradiating section 16 can form a variable light distribution pattern P2 above the diffusion pattern P1 as shown in FIG. 2(a) by irradiating light from the multiple light sources 27a. At least a portion of the variable light distribution pattern P2 is formed in an area above the diffusion pattern P1. The variable light distribution pattern P2 has a structure in which multiple partial areas P3 arranged in a matrix are collected. As an example, each partial area P3 corresponds one-to-one to each light source 27a. The illuminance of each partial area P3 can be adjusted independently of one another by adjusting the lighting state of each light source 27a.

[0038] The second irradiator 16 can form a cutoff line pattern P4 as shown in FIG. 2(b) by adjusting the illuminance of each partial region P3. The cutoff line pattern P4 includes a cutoff line CL and multiple partial regions P3. The cutoff line CL is located above the diffusion pattern P1. The cutoff line CL is a boundary between a partial region P3 located above the cutoff line CL and having a relatively low illuminance (preferably 0 illuminance) and a partial region P3 located below the cutoff line CL and having a relatively high illuminance, and has a known shape. As an example, the cutoff line CL includes a first portion extending horizontally on the oncoming lane side, a second portion extending horizontally on the own lane side and at a position higher than the first portion, and a third portion extending obliquely between the first and second portions and connecting them. The multiple partial regions P3 are aligned along the cutoff line CL below the cutoff line CL. In this embodiment, the multiple partial regions P3 are also arranged in a direction perpendicular to the cutoff line CL.

[0039] The low beam unit 2 of this embodiment forms a low beam light distribution pattern P5 by combining a diffusion pattern P1 and a cutoff line pattern P4. Therefore, the low beam light distribution pattern P5 includes a diffusion pattern P1 that spreads in the vehicle width direction, a cutoff line CL located above the diffusion pattern P1, and a plurality of partial regions P3 located below the cutoff line CL.

[0040] The ADB unit 4 can form an ADB light distribution pattern P6 as shown in FIGS. 2(a) and 2(b) by a combination of turning on and off the second light source 28, rotating the rotating reflector 32, and driving the drive mechanism 38. At least a portion of the ADB light distribution pattern P6 is formed in an area above the cutoff line CL. As an example, the ADB light distribution pattern P6 is formed in an area where a known high beam light distribution pattern would be formed. Furthermore, when a forward vehicle is detected by the vehicle detection device 6, the ADB light distribution pattern P6 includes a second illuminance reduction portion 44 that overlaps with the forward vehicle as shown in FIG. 3. The formation of the second illuminance reduction portion 44 is controlled by the light distribution control device 8.

[0041] When there is a forward vehicle, the light distribution control device 8 controls the formation of a light distribution pattern by the low beam unit 2 and the ADB unit 4 as follows. That is, the light distribution control device 8 determines the position of the forward vehicle 100 based on the detection result of the vehicle detection device 6. The position of the forward vehicle 100 determined by the light distribution control device 8 includes the position (angle) of the host vehicle in the vehicle width direction. When the light distribution control device 8 acquires an image IMG as the detection result of the vehicle detection device 6, it can determine the position of the forward vehicle 100 by known image processing or image analysis.

[0042] The light distribution control device 8 determines a second illuminance reduction section 44 that overlaps with the forward vehicle 100 in the ADB light distribution pattern P6. Then, it controls the ADB unit 4 to form the ADB light distribution pattern P6 including the second illuminance reduction section 44. The second illuminance reduction section 44 in this embodiment is a shading section whose illuminance is substantially zero. Note that the second illuminance reduction section 44 may also be a dimming section whose illuminance is higher than that of the shading section and lower than that of other areas excluding the shading section. The illuminance of the second illuminance reduction section 44 can be set appropriately based on experiments and simulations, taking into account the degree of glare received by the driver of the forward vehicle, etc.

[0043] Furthermore, the light distribution control device 8 determines, as the specific partial area P3a, the partial area P3 that overlaps with the forward vehicle 100 in terms of its position in the vehicle width direction among the multiple partial areas P3 in the low beam light distribution pattern P5. Therefore, the position of the specific partial area P3a in the vehicle width direction of the host vehicle overlaps with the position of the forward vehicle 100 in the vehicle width direction. Then, the low beam unit 2 is controlled to reduce the illuminance of the specific partial area P3a below the illuminance of the other partial areas P3. As a result, a first illuminance reduction section 46 is formed in the specific partial area P3a. The first illuminance reduction section 46 can be made up of multiple partial areas P3.

[0044] The light distribution control device 8 of this embodiment determines the first illuminance reduction portion 46 based on the position of the second illuminance reduction portion 44. In other words, the light distribution control device 8 determines, as a specific partial region P3a, a partial region P3 whose position in the vehicle width direction overlaps with the position of the second illuminance reduction portion 44 in the vehicle width direction, among the multiple partial regions P3 in the low beam light distribution pattern P5, and forms the first illuminance reduction portion 46 in this specific partial region P3a. Note that this is not limiting, and the light distribution control device 8 may also determine the first illuminance reduction portion 46 directly from the detection result of the vehicle detection device 6.

[0045] The height direction range of the first illuminance reduction section 46, in other words, the extent to which the partial area P3 from the cutoff line CL is defined as the specific partial area P3a, can be set appropriately based on experiments and simulations, taking into account the pitching range of the vehicle, etc.

[0046] The light distribution control device 8 also determines the illuminance of the first illuminance reduction unit 46 as follows. FIG. 4 is a schematic diagram illustrating a method for setting the illuminance of the first illuminance reduction unit 46. As an example, the light distribution control device 8 reduces the illuminance of the first illuminance reduction unit 46 as the distance from the host vehicle to the forward vehicle 100 decreases. The light distribution control device 8 can determine the distance to the forward vehicle 100 based on the detection results of the distance measurement sensor provided in the vehicle detection device 6. The forward vehicle 100 tends to increase in its widthwise dimension on the image IMG as it approaches the host vehicle. Therefore, the distance to the forward vehicle 100 can be calculated from the widthwise dimension of the forward vehicle 100 on the image IMG. For example, the light distribution control device 8 previously stores a conversion table that associates the distance to the forward vehicle 100 with the illuminance of the first illuminance reduction unit 46, and determines the illuminance of the first illuminance reduction unit 46 using this conversion table. The dimension of the second illuminance reduction section 44 in the vehicle width direction may be considered as the dimension of the forward vehicle 100 in the vehicle width direction.

[0047] Furthermore, the distance from the host vehicle to the forward vehicle 100 can be estimated from the position of the forward vehicle 100 or the first illuminance reduction unit 46 in the vehicle width direction. In other words, the forward vehicle 100 tends to move outward in the vehicle width direction relative to the host vehicle as it approaches the host vehicle. If the forward vehicle 100 moves outward in the vehicle width direction, the first illuminance reduction unit 46 also moves outward in the vehicle width direction. Therefore, as another example, the light distribution control device 8 reduces the illuminance of the first illuminance reduction unit 46 as the forward vehicle 100 is positioned more outward in the vehicle width direction or the first illuminance reduction unit 46 is positioned more outward in the vehicle width direction. For example, the light distribution control device 8 previously stores a conversion table that associates the position of the forward vehicle 100 or the first illuminance reduction unit 46 in the vehicle width direction with the illuminance, and determines the illuminance of the first illuminance reduction unit 46 using this conversion table. The position of the forward vehicle 100 or the first illuminance reduction unit 46 in the vehicle width direction is based on, for example, the center in the vehicle width direction, or the inner or outer end in the vehicle width direction. Note that the position of the second illuminance reduction unit 44 in the vehicle width direction may be considered as the position of the forward vehicle 100 in the vehicle width direction.

[0048] Furthermore, the distance from the host vehicle to the forward vehicle 100 can be estimated from the vehicle width dimension of the forward vehicle 100 or the first illuminance reduction unit 46. That is, as described above, the forward vehicle 100 tends to increase in the vehicle width dimension on the image IMG as it approaches the host vehicle. As the forward vehicle 100 increases in size, the first illuminance reduction unit 46 also increases in size. Therefore, as another example, the light distribution control device 8 decreases the illuminance of the first illuminance reduction unit 46 as the vehicle width dimension of the forward vehicle 100 or the vehicle width dimension of the first illuminance reduction unit 46 increases. For example, the light distribution control device 8 previously stores a conversion table that associates the vehicle width dimension of the forward vehicle 100 or the first illuminance reduction unit 46 with the illuminance, and determines the illuminance of the first illuminance reduction unit 46 using this conversion table. Note that the vehicle width dimension of the second illuminance reduction unit 44 may be considered as the vehicle width dimension of the forward vehicle 100.

[0049] The illuminance of the first illuminance reduction section 46 for each distance to the forward vehicle 100, each position of the forward vehicle 100 or the first illuminance reduction section 46, and each size of the forward vehicle 100 or the first illuminance reduction section 46 can be set appropriately based on experiments and simulations, taking into account the degree of glare received by the driver of the forward vehicle, etc.

[0050] 5 is a flowchart showing an example of light distribution control executed by the light distribution control device 8. This flow is executed repeatedly at a predetermined timing when an instruction to execute light distribution control is given by a light switch (not shown), for example, and the ignition is on. Note that the following explanation illustrates a case where an image IMG is used as the detection result of the vehicle detection device 6.

[0051] The light distribution control device 8 determines whether an image IMG has been acquired (S101). If an image IMG has not been acquired (N in S101), this routine ends. If an image IMG has been acquired (Y in S101), the light distribution control device 8 determines whether a forward vehicle 100 exists using the image IMG (S102). If a forward vehicle 100 exists (Y in S102), the light distribution control device 8 determines a light distribution pattern for low beam P5 including the first illuminance reduction unit 46 and a light distribution pattern for ADB P6 including the second illuminance reduction unit 44 (S103).

[0052] If there is no forward vehicle 100 (N in S102), the light distribution control device 8 determines a low beam light distribution pattern P5 that does not include the first illuminance reduction unit 46 and an ADB light distribution pattern P6 that does not include the second illuminance reduction unit 44 (S104). Then, the light distribution control device 8 controls the low beam unit 2 and the ADB unit 4 to form the determined low beam light distribution pattern P5 and ADB light distribution pattern P6 (S105), and ends this routine.

[0053] As described above, the vehicle lighting system 1 according to this embodiment includes the low beam unit 2 and the light distribution control device 8. The low beam unit 2 is capable of forming a low beam light distribution pattern P5 having a cutoff line CL, and is also capable of independently adjusting the illuminance of a plurality of partial regions P3 in the low beam light distribution pattern P5 that are aligned along the cutoff line CL below the cutoff line. The light distribution control device 8 controls the low beam unit 2 to form a first illuminance reduction portion 46 in a partial region P3 (specific partial region P3a) among the plurality of partial regions P3 whose position in the vehicle width direction overlaps with the position of the forward vehicle 100 in the vehicle width direction.

[0054] By forming the second illuminance reduction portion 44 in the ADB light distribution pattern P6, the glare received by the driver of the forward vehicle 100 due to the ADB light distribution pattern P6 can be reduced. However, if the vehicle pitches due to an uneven road surface or the like, the pitching may cause the low beam light distribution pattern P5 to be irradiated onto the driver of the forward vehicle. Then, the driver of the forward vehicle 100 may be subjected to glare due to the irradiation of this low beam light distribution pattern P5.

[0055] In response to this, by forming the first illuminance reduction portion 46 in the partial region P3 in the low beam light distribution pattern P5 whose position in the vehicle width direction coincides with that of the forward vehicle 100, the first illuminance reduction portion 46 can be overlapped with the forward vehicle 100 when the host vehicle pitches. This makes it possible to reduce the glare received by the driver of the forward vehicle 100 due to the low beam light distribution pattern P5. Therefore, compared to conventional ADB control, the glare received by the driver of the forward vehicle 100 can be further reduced.

[0056] Furthermore, as an example, the light distribution control device 8 of this embodiment reduces the illuminance of the first illuminance reduction unit 46 as the distance to the forward vehicle 100 becomes shorter. Generally, the closer the forward vehicle 100 is, the more likely the driver of the forward vehicle 100 is to be subjected to glare due to light irradiation from the vehicle itself. Therefore, by reducing the illuminance of the first illuminance reduction unit 46 as the distance to the forward vehicle 100 becomes shorter, it is possible to further reduce the glare received by the driver of the forward vehicle 100. Furthermore, by increasing the illuminance of the first illuminance reduction unit 46 corresponding to a forward vehicle 100 that is farther away, it is possible to reduce the decrease in visibility for the driver of the vehicle itself.

[0057] As another example, the light distribution control device 8 of this embodiment reduces the illuminance of the first illuminance reduction unit 46 as the forward vehicle 100 or the first illuminance reduction unit 46 is positioned further outward in the vehicle width direction. In this way, by changing the standard for determining the illuminance of the first illuminance reduction unit 46 from the distance to the forward vehicle 100 to the position of the forward vehicle 100 or the first illuminance reduction unit 46 in the vehicle width direction, it is possible to simplify the light distribution control. As a result, it is possible to speed up the light distribution control and reduce the load on the light distribution control device 8.

[0058] As another example, the light distribution control device 8 of this embodiment reduces the illuminance of the first illuminance reduction unit 46 as the dimension in the vehicle width direction of the forward vehicle 100 or the first illuminance reduction unit 46 increases. In this way, by replacing the standard for determining the illuminance of the first illuminance reduction unit 46 from the distance to the forward vehicle 100 to the dimension in the vehicle width direction of the forward vehicle 100 or the first illuminance reduction unit 46, it is possible to simplify the light distribution control. As a result, it is possible to speed up the light distribution control and reduce the load on the light distribution control device 8.

[0059] The low-beam light distribution pattern P5 of this embodiment includes a diffusion pattern P1 that spreads in the vehicle width direction, a cutoff line CL located above the diffusion pattern P1, and a plurality of partial regions P3 located below the cutoff line CL. The low-beam unit 2 includes a first irradiation section 14 that has optical members (such as a first projection lens 26 and a reflector) that diffuse light from the first light source 18 in the vehicle width direction and forms the diffusion pattern P1, and a second irradiation section 16 that has a structure in which a plurality of light sources 27a that can be turned on and off independently are arranged and forms the cutoff line CL and the plurality of partial regions P3. This allows a first illuminance reduction section 46 to be formed in the low-beam light distribution pattern P5.

[0060] The vehicle lighting system 1 of the present embodiment also includes an ADB unit 4 capable of forming an ADB light distribution pattern P6 including a second illuminance reduction portion 44, at least a portion of which is formed in an area above the cutoff line CL and overlaps with the forward vehicle 100. The light distribution control device 8 determines the second illuminance reduction portion 44 in the ADB light distribution pattern P6, and forms a first illuminance reduction portion 46 in a partial area P3 of a plurality of partial areas P3 in the low beam light distribution pattern P5 whose position in the vehicle width direction overlaps with the position of the second illuminance reduction portion 44 in the vehicle width direction. This makes it possible to form the first illuminance reduction portion 46 in the low beam light distribution pattern P5 in cooperation with the formation of the second illuminance reduction portion 44 in the ADB light distribution pattern P6. As a result, light distribution control can be simplified, and the light distribution control can be speeded up and the load on the light distribution control device 8 can be reduced.

[0061] The above describes the embodiments of the present invention in detail. The above-described embodiments merely illustrate specific examples of implementing the present invention. The content of the embodiments does not limit the technical scope of the present invention, and many design modifications, such as changes, additions, and deletions of components, are possible within the scope of the inventive concept defined in the claims. A new embodiment incorporating design modifications will combine the effects of the combined embodiments and modifications. In the above-described embodiments, design modifications that are possible are emphasized by using notations such as "in this embodiment" or "in this embodiment," but design modifications are also permitted even in areas without such notation. Any combination of the above components is also valid as an aspect of the present invention. Hatching in cross sections in the drawings does not limit the materials of the hatched objects.

[0062] The light distribution control device 8 in the embodiment changes the illuminance of the first illuminance reduction unit 46 depending on the distance from the host vehicle to the preceding vehicle 100, or depending on the position of the preceding vehicle 100 or the first illuminance reduction unit 46 in the vehicle width direction, or depending on the dimension of the preceding vehicle 100 or the first illuminance reduction unit 46 in the vehicle width direction. However, this is not limiting, and the light distribution control device 8 may uniformly set the illuminance of the first illuminance reduction unit 46 to zero. This can further simplify the light distribution control, make it easier to speed up the light distribution control, and reduce the load on the light distribution control device 8. In addition, the glare received by the driver of the preceding vehicle can be further reduced.

[0063] The invention according to the above-described embodiment may be specified by the following items. (Item 1) a low beam unit (2) capable of forming a low beam light distribution pattern (P5) having a cutoff line (CL) and capable of independently adjusting the illuminance of a plurality of partial regions (P3) arranged below and along the cutoff line (CL) in the low beam light distribution pattern (P5); and a light distribution control device (8) that controls the low beam unit (2) to form a first illuminance reduction section (46) in a partial region (P3) among the plurality of partial regions (P3) whose position in the vehicle width direction overlaps with the position of a forward vehicle (100) in the vehicle width direction. Vehicle lighting system (1).

[0064] (Item 2) A light distribution control device (8) is capable of forming a low beam light distribution pattern (P5) having a cutoff line (CL), and controlling a low beam unit (2) that can independently adjust illuminance of a plurality of partial regions (P3) arranged below and along the cutoff line (CL) in the low beam light distribution pattern (P5), controlling the low beam unit (2) to form a first illuminance reduction portion (46) in a partial region (P3) whose position in the vehicle width direction overlaps with the position of a forward vehicle (100) in the vehicle width direction, among the plurality of partial regions (P3); Light distribution control device (8).

[0065] (Item 3) A light distribution control method for controlling the formation of a low beam light distribution pattern (P5) having a cutoff line (CL), forming a first illuminance reduction portion (46) in a partial region (P3) of a low beam light distribution pattern (P5) that is arranged below and along a cutoff line (CL), the partial region (P3) having a position in a vehicle width direction that overlaps with the position of a forward vehicle (100) in the vehicle width direction; Light distribution control method. [Industrial Applicability]

[0066] The present invention can be used in a vehicle lighting system, a light distribution control device, and a light distribution control method. [Explanation of symbols]

[0067] 1 vehicle lighting system, 2 low beam unit, 4 ADB unit, 8 light distribution control device, 14 first irradiation section, 16 second irradiation section, 44 second illuminance reduction section, 46 first illuminance reduction section, 100 forward vehicle.

Claims

1. a low beam unit capable of forming a low beam light distribution pattern having a cutoff line, and capable of independently adjusting illuminances of a plurality of partial regions arranged along the cutoff line below the cutoff line in the low beam light distribution pattern; a light distribution control device that controls the low beam unit to form a first illuminance reduction portion in a partial region, among the plurality of partial regions, whose position in a vehicle width direction overlaps with the position of a forward vehicle in the vehicle width direction, a range in a height direction of the first illuminance reducing unit is set based on a pitching range of the host vehicle; Vehicle lighting system.

2. the light distribution control device reduces the illuminance of the first illuminance reduction unit as the distance to the forward vehicle becomes shorter, 2. The vehicle lighting system according to claim 1.

3. the light distribution control device reduces the illuminance of the first illuminance reduction unit as the forward vehicle or the first illuminance reduction unit is positioned more outward in a vehicle width direction, 2. The vehicle lighting system according to claim 1.

4. the light distribution control device reduces the illuminance of the first illuminance reduction portion as the dimension of the forward vehicle or the first illuminance reduction portion in the vehicle width direction increases, 2. The vehicle lighting system according to claim 1.

5. The light distribution control device sets the illuminance of the first illuminance reducing unit to zero.

2. The vehicle lighting system according to claim 1.

6. the low beam light distribution pattern includes a diffusion pattern spreading in a vehicle width direction, the cutoff line located above the diffusion pattern, and the plurality of partial regions located below the cutoff line, The low beam unit includes a first irradiation unit that has an optical member that diffuses light from a light source in a vehicle width direction and forms the diffusion pattern, and a second irradiation unit that has a structure in which a plurality of light sources that can be turned on and off independently of each other are arranged and forms the cut-off line and the plurality of partial areas.

6. A vehicle lighting system according to claim 1.

7. the vehicle lighting system includes an ADB unit capable of forming an ADB light distribution pattern including a second illuminance reduction portion at least a portion of which is formed in an area above the cutoff line and overlaps with the forward vehicle, the light distribution control device determines the second illuminance reduction portion in the light distribution pattern for ADB, and forms a first illuminance reduction portion in a partial region of the plurality of partial regions in the light distribution pattern for low beam, the partial region having a position in the vehicle width direction that overlaps with a position of the second illuminance reduction portion in the vehicle width direction, 7. A vehicle lighting system according to claim 1.

8. A light distribution control device that controls a low beam unit capable of forming a low beam light distribution pattern having a cutoff line and independently adjusting illuminances of a plurality of partial regions arranged along the cutoff line below the cutoff line in the low beam light distribution pattern, controlling the low beam unit to form a first illuminance reduction portion in a partial region, among the plurality of partial regions, whose position in a vehicle width direction overlaps with a position of a forward vehicle in the vehicle width direction; a range in a height direction of the first illuminance reducing unit is set based on a pitching range of the host vehicle; Light distribution control device.

9. A light distribution control method for controlling formation of a low beam light distribution pattern having a cutoff line, forming a first illuminance reduction portion in a partial region, the partial region being positioned in a vehicle width direction and overlapping a position of a forward vehicle in the vehicle width direction, among a plurality of partial regions arranged below a cutoff line and along the cutoff line in the low beam distribution pattern, a range in a height direction of the first illuminance reducing unit is set based on a pitching range of the host vehicle; Light distribution control method.

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