Light distribution control device, vehicle lighting system, and light distribution control method

Abstract

A light distribution control device (6), if a first upper limit number (N1) is greater than or equal to the number of near-distance targets (T1), controls a variable light distribution lamp (2) to irradiate the near-distance targets with light having illuminance according to attributes of the near-distance targets; if a remaining number (M) obtained by subtracting the number of near-distance targets (T1) from the first upper limit number (N1) is greater than or equal to the number of long-distance targets (T2), controls the variable light distribution lamp (2) to irradiate the long-distance targets with light having illuminance according to attributes of the long-distance targets; if the first upper limit number (N1) is less than the number of near-distance targets (T1), controls the variable light distribution lamp (2) to form a light distribution pattern (PTN) that does not depend on the near-distance targets and the long-distance targets; and, if the remaining number (M) is less than the number of long-distance targets (T2), controls the variable light distribution lamp (2) to form a light distribution pattern (PTN) that does not depend on the long-distance targets.

Description

[Technical Field]

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

[0002] ADB (Adaptive Dynamic Braking) is a system that dynamically and adaptively controls the light distribution pattern based on the vehicle's surroundings. ADB control is a method to prevent high-intensity light exposure. The system uses a camera to detect the presence or absence of a vehicle ahead and shades the area corresponding to the vehicle ahead (see, for example, Patent Document 1). By shading the area corresponding to the vehicle ahead, it is possible to reduce the glare given to the driver of the vehicle ahead and improve the visibility of the driver of the vehicle itself. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-088224 Summary of the Invention [Problem to be solved by the invention]

[0004] In conventional ADB control, the target of light distribution control has been mainly the vehicle ahead. However, in order to further improve the driver's visibility, it is desirable to also target objects other than the vehicle ahead with light distribution control. For example, light-reflecting objects such as road signs, delineators, and billboards can cause the driver of the vehicle to be distracted by the reflected light. person For this reason, it is desirable to set the area corresponding to the light-reflecting object as a target of light distribution control and reduce the light. It is also desirable for the driver of the vehicle to be able to see pedestrians, obstacles on the road (such as fallen objects), road markings, etc., as soon as possible. For this reason, it is desirable to set the area corresponding to pedestrians, etc. as a target of light distribution control and increase the light.

[0005] On the other hand, as the number of targets for light distribution control increases, the light distribution pattern will change frequently. If the light distribution pattern changes frequently, the driver of the vehicle may feel visually annoyed. This visual annoyance may lead to a decrease in the driver's visibility.

[0006] The present invention has been made in view of the above circumstances, and one of its objectives is to provide a technique for reducing the visual annoyance experienced by a driver due to light distribution control. [Means for solving the problem]

[0007] In order to solve the above problems, one aspect of the present invention is a light distribution control device that controls the light distribution of a variable light distribution lamp in accordance with targets present in a region ahead of a vehicle. The targets include short-distance targets located within a predetermined distance from the vehicle and long-distance targets located beyond the predetermined distance. This light distribution control device controls the variable light distribution lamp to irradiate short-distance targets with light of an illuminance corresponding to the attributes of the long-distance targets when a first upper limit number N1 of targets that can be subject to light distribution control is equal to or greater than the number T1 of short-distance targets; controls the variable light distribution lamp to irradiate long-distance targets with light of an illuminance corresponding to the attributes of the long-distance targets when a remaining number M obtained by subtracting the number T1 of short-distance targets from the first upper limit number N1 is equal to or greater than the number T2 of long-distance targets; controls the variable light distribution lamp to form a light distribution pattern that is independent of short-distance targets and long-distance targets when the first upper limit number N1 is less than the number T1 of short-distance targets; and controls the variable light distribution lamp to form a light distribution pattern that is independent of long-distance targets when the remaining number M is less than the number T2 of long-distance targets.

[0008] Another aspect of the present invention is a vehicle lighting system including a variable light distribution lamp capable of irradiating a forward area with a visible light beam having a variable intensity distribution, and the light distribution control device according to the above aspect.

[0009] Another aspect of the present invention is a light distribution control method for controlling the light distribution of a variable light distribution lamp according to targets present in a region ahead of a vehicle. The targets include short-distance targets located within a predetermined distance from the vehicle and long-distance targets located beyond the predetermined distance. This light distribution control method controls the variable light distribution lamp to irradiate the short-distance targets with light at an illuminance corresponding to the attributes of the short-distance targets when a first upper limit number N1 of targets that can be subject to light distribution control is equal to or greater than the number T1 of short-distance targets; controls the variable light distribution lamp to irradiate the long-distance targets with light at an illuminance corresponding to the attributes of the long-distance targets when a remaining number M obtained by subtracting the number T1 of short-distance targets from the first upper limit number N1 is equal to or greater than the number T2 of long-distance targets; controls the variable light distribution lamp to form a light distribution pattern that is independent of short-distance targets and long-distance targets when the first upper limit number N1 is less than the number T1 of short-distance targets; and controls the variable light distribution lamp to form a light distribution pattern that is independent of long-distance targets when the remaining number M is less than the number T2 of long-distance targets.

[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 visual annoyance experienced by the driver due to light distribution control. [Brief explanation of the drawings]

[0012] [Figure 1] 1 is a block diagram of a vehicle lighting system according to an embodiment; [Figure 2] FIG. 2 is a diagram showing the state of the area ahead of the host vehicle. [Figure 3] 10 is a flowchart illustrating a flow of light distribution control executed by a light distribution control device. [Figure 4] 10 is a flowchart illustrating a flow of light distribution control executed by a light distribution control device. [Figure 5] 5(A) and 5(B) are flowcharts illustrating the flow of light distribution control executed by the 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 block diagram 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 an adjustable light distribution lamp 2, an imaging device 4, and a light distribution control device 6. These may all be housed in the same housing, or some components may be provided outside the housing. For example, the adjustable light distribution lamp 2, imaging device 4, and light distribution control device 6 are housed in a lamp chamber. The lamp chamber is defined by a lamp body having an opening on the front side of the vehicle and a translucent cover attached to cover the opening of the lamp body. The imaging device 4 and light distribution control device 6 may be located outside the lamp chamber, for example, on the vehicle side. In this case, the imaging device 4 may be an on-board camera. Furthermore, the light distribution control device 6 may be configured, for example, in whole or in part, by a vehicle ECU.

[0016] The variable light distribution lamp 2 is capable of irradiating a visible light beam L1 with a variable intensity distribution onto an area in front of the vehicle. The variable light distribution lamp 2 is capable of individually changing the illuminance of light irradiated onto a plurality of individual areas R arranged in the area in front of the vehicle. The plurality of individual areas R are arranged, for example, in a matrix. The variable light distribution lamp 2 receives information instructing a light distribution pattern PTN from a light distribution control device 6, and emits a visible light beam L1 having an intensity distribution according to the light distribution pattern PTN. This forms the light distribution pattern PTN in front of the vehicle. The light distribution pattern PTN can be understood as the two-dimensional illuminance distribution of an irradiation pattern 902 formed by the variable light distribution lamp 2 on a virtual vertical screen 900 in front of the vehicle.

[0017] The configuration of the variable light distribution lamp 2 is not particularly limited, and may include, for example, a plurality of light sources arranged in a matrix and a lighting circuit that independently drives and lights each light source. Preferred examples of light sources include semiconductor light sources such as LEDs (light-emitting diodes), LDs (laser diodes), and organic or inorganic ELs (electroluminescence). Each individual region R is associated with a light source, and each light source individually irradiates each individual region R with light. The resolution of the variable light distribution lamp 2, in other words, the light distribution resolution, is, for example, 1,000 to 2,000,000 pixels. The resolution of the variable light distribution lamp 2 refers to the number of unit regions whose illuminance can be independently changed in the light distribution pattern PTN.

[0018] The variable light distribution lamp 2 uses a matrix type pattern forming device such as a DMD (Digital Mirror Device) or a liquid crystal device to form an illuminance distribution according to the light distribution pattern PTN. The device may include a chair, a scanning optical pattern forming device that scans the area in front of the vehicle with light from a light source, or the like.

[0019] The imaging device 4 is sensitive to the visible light region and repeatedly captures images of the area ahead of the vehicle. The imaging device 4 captures reflected light L2 of the visible light beam L1 by an object ahead of the vehicle, light emitted by a vehicle ahead, and the like. It is sufficient for the imaging device 4 to be sensitive to at least the wavelength region of the visible light beam L1. The image IMG generated by the imaging device 4 is sent to the light distribution control device 6.

[0020] The image IMG acquired by the light distribution control device 6 may be RAW image data, or may be image data that has undergone predetermined image processing by the imaging device 4 or another processing unit. In the following description, "image IMG based on the imaging device 4" means that it may be either RAW image data or data that has undergone image processing. In addition, both types of image data may sometimes be expressed as "image IMG" without making a distinction between them.

[0021] The light distribution control device 6 executes ADB control, which dynamically and adaptively controls the light distribution of the variable light distribution lamp 2 according to the target object present in the forward area. The light distribution control device 6 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 an FPGA (Field Programmable Gate Array) or an ASIC (Application Specific IC). The light distribution control device 6 includes, for example, a target object analysis unit The light distribution control device 6 has a control unit 8 and a pattern determination unit 10. Each unit operates when the integrated circuit that constitutes it executes a program stored in the memory. Hereinafter, the control of the formation of a light distribution pattern by the light distribution control device 6 will be described.

[0022] FIG. 2 is a diagram showing the state of the area ahead of the host vehicle V. The target analysis unit 8 classifies the targets present in the area ahead. Specifically, the targets present in the area ahead are classified into forward vehicles 12, including preceding vehicles and oncoming vehicles, and other targets. Targets other than the forward vehicle 12 include pedestrians, road signs, delineators, signboards, road markings, obstacles, etc. The target analysis unit 8 also classifies the targets other than the forward vehicle 12 into short-distance targets 14 located within a predetermined distance from the host vehicle and long-distance targets 16 located outside the predetermined distance. The target analysis unit 8 then calculates the number S of the forward vehicles 12, the number T1 of the short-distance targets 14, and the number T2 of the long-distance targets 16.

[0023] For example, the target analysis unit 8 stores a predetermined distance threshold in advance, and a target at a distance less than the predetermined distance threshold is considered to be a short-distance target 14, and a target at a distance equal to or greater than the distance threshold is considered to be a long-distance target 16. The distance threshold is determined, for example, based on the braking distance of the host vehicle V. Therefore, the distance threshold changes according to the vehicle speed of the host vehicle V. In other words, a short-distance target 14 is a target that the host vehicle V cannot stop in front of, and a long-distance target 16 is a target that the host vehicle V can stop in front of. The distance threshold can be set appropriately based on experiments or simulations.

[0024] Furthermore, the target analysis unit 8 grasps the attributes of each of the short-distance target 14 and the long-distance target 16. The target analysis unit 8 of this embodiment grasps the brightness and position of each target as the attributes of the target.

[0025] As an example, the target analysis unit 8 classifies targets and identifies their attributes using the image IMG captured by the imaging device 4. The target analysis unit 8 can determine the type of target, i.e., whether it is a preceding vehicle 12 or a target other than the preceding vehicle 12, by performing known image processing and image analysis on the image IMG. In addition, the distance to each target can be detected from the ground position of each target in the image IMG. This allows for classification into close-range targets 14 and long-range targets 16. In addition, the attributes of each target, i.e., its position and brightness, can be identified from the image IMG.

[0026] The target analysis unit 8 may separate targets and ascertain their attributes using target information obtained from a ranging sensor or the like. The ranging sensor is oriented in the measurement direction toward the forward area and acquires information about the forward area. The ranging sensor may be configured with, for example, a millimeter-wave radar or a LiDAR (Light Detection and Ranging or Laser Imaging Detection and Ranging).

[0027] Then, the target analysis unit 8 sends the target classification results, including the number of each target, and information on the attributes of each target to the pattern determination unit 10.

[0028] 3, 4, 5(A), and 5(B) are flowcharts illustrating the flow of light distribution control (ADB control) executed by the light distribution control device 6. Connector A in Fig. 3 is connected to connector A in Fig. 4. Connector B in Fig. 3 is connected to connector B in Fig. 4. This flow is repeatedly executed at 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.

[0029] 3, first, the pattern determination unit 10 determines whether an instruction for the light distribution pattern PTN to be formed has been received from the vehicle ECU (S101). If an instruction for the light distribution pattern PTN has been received from the vehicle ECU (Y in S101), the pattern determination unit 10 controls the variable light distribution lamp 2 to form the light distribution pattern PTN in accordance with the instruction from the vehicle ECU (S102), and ends this routine. Note that if an instruction for the light distribution pattern PTN has been received from the vehicle ECU, the target analysis by the target analysis unit 8 can be omitted. Furthermore, the processing of step S101 can be omitted if the light distribution control device 6 is configured by the vehicle ECU.

[0030] If there is no instruction for a light distribution pattern PTN from the vehicle ECU (N in S101), the pattern determination unit 10 determines whether a target exists in the area ahead of the host vehicle V based on information obtained from the target analysis unit 8 (S103). The pattern determination unit 10 determines whether there are any targets, including the preceding vehicle 12, the short-distance target 14, and the long-distance target 16. If there are no targets in the area ahead (N in S103), the pattern determination unit 10 determines a light distribution pattern PTN that prioritizes ensuring visibility for the driver of the host vehicle V as the light distribution pattern PTN to be formed. In this embodiment, as an example, a well-known high-beam light distribution pattern Hi is determined as the light distribution pattern PTN to be formed. Then, the variable light distribution lamp 2 is controlled to form the high-beam light distribution pattern Hi (S104), and this routine ends.

[0031] If a target object is present in the forward area (Y in S103), the pattern determination unit 10 determines whether the second upper limit number N2 is equal to or greater than the number S of forward vehicles 12 (S105). The second upper limit number N2 is stored in advance in the pattern determination unit 10. As an example, the second upper limit number N2 is the maximum number of targets that can be subject to light distribution control in the light distribution control device 6. The second upper limit number N2 can be set appropriately based on experiments or simulations depending on, for example, the relationship between the frequency of switching the light distribution pattern by ADB control and the visual annoyance felt by the driver of the host vehicle V, the performance of the light distribution control device 6, etc. The second upper limit number N2 is a value greater than the first upper limit number N1, which will be described later.

[0032] If the second upper limit number N2 is less than the number S of forward vehicles 12 (N in S105), the pattern determination unit 10 determines, as the light distribution pattern PTN to be formed, a light distribution pattern PTN that does not depend on the presence of forward vehicles 12, the presence and attributes of short-distance targets 14, or the presence and attributes of long-distance targets 16. In this embodiment, as an example, a well-known low-beam light distribution pattern Lo is determined as the light distribution pattern PTN to be formed. Then, the variable light distribution lamp 2 is controlled to form the low-beam light distribution pattern Lo (S106), and this routine ends.

[0033] If the second upper limit number N2 is equal to or greater than the number S of forward vehicles 12 (Y in S105), the pattern determination unit 10 controls the variable light distribution lamp 2 to form a light-blocking portion relative to the forward vehicles 12. In this embodiment, as shown in FIG. 4, a first light distribution pattern PTN1 including a light-blocking portion relative to the forward vehicles 12 is determined as the light distribution pattern PTN to be formed (S107). This results in ADB control being performed at least for the forward vehicles 12. As an example, the illuminance of the light-blocking portion is substantially zero. Note that the illuminance of the light-blocking portion may be higher than zero and can be appropriately set based on experiments or simulations. Then, the pattern determination unit 10 subtracts the number S of forward vehicles 12 from the second upper limit number N2 to calculate a first upper limit number N1 (N1 = N2 - S) (S108). The first upper limit number N1 refers to the number of targets other than the forward vehicles 12 that can be subject to light distribution control by the light distribution control device 6.

[0034] Next, the pattern determination unit 10 determines whether the first upper limit number N1 is equal to or greater than the number T1 of short-distance targets 14 (S109). If the first upper limit number N1 is less than the number T1 of short-distance targets 14 (N in S109), the pattern determination unit 10 determines, as the light distribution pattern PTN to be formed, a light distribution pattern PTN that is independent of the existence and attributes of short-distance targets 14 and the existence and attributes of long-distance targets 16. In this embodiment, the first light distribution pattern PTN1 is determined as the light distribution pattern PTN to be formed. Then, the variable light distribution lamp 2 is controlled to form the first light distribution pattern PTN1 (S110), and this routine ends.

[0035] When the first upper limit number N1 is equal to or greater than the number T1 of short-distance targets 14 (Y in S109), the pattern determination unit 10 controls the variable light distribution lamp 2 to irradiate the short-distance targets 14 with light of an illuminance according to the attributes of the short-distance targets 14. The pattern determination unit 10 of the present embodiment executes a process of determining a second light distribution pattern PTN2 (S111) in order to determine the illuminance according to the attributes of the short-distance targets 14. As a result, ADB control is executed for at least the preceding vehicle 12 and the short-distance targets 14.

[0036] As shown in FIG. 5A, in the process of determining the second light distribution pattern PTN2, the pattern determination unit 10 first determines whether there is a high-luminance short-distance target 14 (S201). For example, the pattern determination unit 10 stores a predetermined luminance threshold value in advance. Then, based on information obtained from the target analysis unit 8, the pattern determination unit 10 determines a short-distance target 14 whose luminance is equal to or greater than the predetermined luminance threshold value as a high-luminance short-distance target 14. The luminance threshold value can be appropriately set based on experiments or simulations. For example, the luminance threshold value is set to a value that can distinguish light-reflecting objects, including road signs, delineators, signboards, etc., from other targets. An example of a light-reflecting object is a target having a retroreflective surface at least in a portion that is visible from the vehicle.

[0037] If there is a high-luminance short-distance target 14 (Y in S201), the pattern determination unit 10 controls the variable light distribution lamp 2 to reduce the illuminance of light irradiated onto the high-luminance short-distance target 14. That is, the pattern determination unit 10 adds a dimming section for the high-luminance short-distance target 14 to the first light distribution pattern PTN1 (S202). The illuminance of the dimming section is, for example, higher than that of the shading section and lower than that before dimming, and is an illuminance that can suppress the glare that a light-reflecting object causes to the driver of the vehicle V. The illuminance of the dimming section can be set appropriately based on experiments or simulations. If there is no high-luminance short-distance target 14 (N in S201), the pattern determination unit 10 skips step S202.

[0038] Next, the pattern determination unit 10 determines whether there is a low-luminance short-distance target 14 on the roadway of the host vehicle V, i.e., within the lane (S203). A low-luminance short-distance target 14 is a short-distance target 14 whose luminance is less than a luminance threshold. If there is a low-luminance short-distance target 14 within the lane (Y in S203), the pattern determination unit 10 controls the variable light distribution lamp 2 to increase the illuminance of light irradiated onto the low-luminance short-distance target 14 within the lane. That is, the pattern determination unit 10 adds a light-increasing portion for the low-luminance short-distance target 14 within the lane to the first light distribution pattern PTN1 (S204). The illuminance of the light-increasing portion is higher than before dimming and is an illuminance that can guide the line of sight of the driver of the host vehicle V to the short-distance target 14 within the lane. The illuminance of the light-increasing portion can be set appropriately based on experiments or simulations. If there is no low-luminance short-distance target 14 within the lane (N in S203), the pattern determination unit 10 skips step S204.

[0039] Through the above processing, the pattern determination unit 10 determines a second light distribution pattern PTN2 in which, if there is a high-luminance short-distance target 14, a dimming section is added for the short-distance target 14, and if there is a low-luminance short-distance target 14 within the lane, a brightening section is added for the short-distance target 14 (S205). For low-luminance short-distance targets 14 outside the lane, light irradiation at the illuminance before dimming is maintained. Next, as shown in FIG. 4, the pattern determination unit 10 subtracts the number T1 of short-distance targets 14 from the first upper limit number N1 to calculate the remaining number M (M = N1 - T1) (S112). The remaining number M refers to the number of targets, other than the preceding vehicle 12 and the short-distance targets 14, that can be subject to light distribution control by the light distribution control device 6.

[0040] Next, the pattern determination unit 10 determines whether the remaining number M is equal to or greater than the number T2 of long-distance targets 16 (S113). If the remaining number M is less than the number T2 of long-distance targets 16 (N in S113), the pattern determination unit 10 determines a light distribution pattern PTN that is independent of the existence and attributes of long-distance targets 16 as the light distribution pattern PTN to be formed. In this embodiment, the second light distribution pattern PTN2 is determined as the light distribution pattern PTN to be formed. Then, the variable light distribution lamp 2 is controlled to form the second light distribution pattern PTN2 (S114), and this routine ends.

[0041] When the remaining number M is equal to or greater than the number T2 of long-distance targets 16 (Y in S113), the pattern determination unit 10 controls the variable light distribution lamp 2 to irradiate the long-distance targets 16 with light of an illuminance according to the attributes of the long-distance targets 16. In this embodiment, the pattern determination unit 10 executes a process of determining a third light distribution pattern PTN3 (S115) in order to determine the illuminance according to the attributes of the long-distance targets 16. As a result, ADB control is executed for the forward vehicle 12, the short-distance targets 14, and the long-distance targets 16.

[0042] As shown in FIG. 5(B), in the process of determining the third light distribution pattern PTN3, the pattern determination unit 10 first determines whether or not there is a high-luminance long-distance target 16 (S301). The method of determining whether or not there is a high-luminance long-distance target 16 is the same as the method of determining whether or not there is a high-luminance short-distance target 14. If there is a high-luminance long-distance target 16 that is equal to or greater than a predetermined luminance threshold (Y in S301), the pattern determination unit 10 controls the variable light distribution lamp 2 to reduce the illuminance of the light irradiating the high-luminance long-distance target 16. That is, the pattern determination unit 10 adds a dimming section for the high-luminance long-distance target 16 to the second light distribution pattern PTN2 (S302). The method of setting the illuminance of the dimming section is the same as the method of setting the illuminance of the dimming section in the process of determining the second light distribution pattern PTN2. If there is no high-luminance long-distance target 16 (N in S301), the pattern determination unit 10 skips step S302.

[0043] Next, the pattern determination unit 10 determines whether there is a low-luminance long-distance target 16 on the roadway of the host vehicle V, i.e., within the lane (S303). A low-luminance long-distance target 16 is a long-distance target 16 whose luminance is less than the luminance threshold value. If there is a low-luminance long-distance target 16 within the lane (Y in S303), the pattern determination unit 10 controls the variable light distribution lamp 2 to increase the illuminance of light irradiated onto the low-luminance long-distance target 16 within the lane. That is, the pattern determination unit 10 adds a light-increasing section for the low-luminance long-distance target 16 within the lane to the second light distribution pattern PTN2 (S304). The method for setting the illuminance of the light-increasing section is the same as the method for setting the illuminance of the light-increasing section in the process for determining the second light distribution pattern PTN2. If there is no low-luminance long-distance target 16 within the lane (N in S303), the pattern determination unit 10 skips step S304.

[0044] Through the above processing, the pattern determination unit 10 determines a third light distribution pattern PTN3 in which, if there is a high-luminance long-distance target 16, a dimming section is added for that long-distance target 16, and if there is a low-luminance long-distance target 16 within the lane, a brightening section is added for that long-distance target 16 (S305). Note that light irradiation at the illuminance before dimming is maintained for low-luminance long-distance targets 16 outside the lane. Next, as shown in FIG. 4, the pattern determination unit 10 controls the variable light distribution lamp 2 to form the determined third light distribution pattern PTN3 (S116), and ends this routine.

[0045] The variable light distribution lamp 2 is driven to form the light distribution pattern PTN determined by the pattern determination unit 10. For example, if the dimming method of the light source is analog dimming, the variable light distribution lamp 2 adjusts the DC level of the drive current flowing through the light source. If the dimming method of the light source is PWM (Pulse Width Modulation) dimming, the variable light distribution lamp 2 adjusts the average level of the drive current by switching the current flowing through the light source and adjusting the ratio of the on period. If the variable light distribution lamp 2 includes a DMD, it may control the on / off switching of each mirror element that makes up the DMD. If the variable light distribution lamp 2 has a liquid crystal device, it may control the light transmittance of the liquid crystal device. As a result, the light distribution pattern PTN is formed in front of the vehicle.

[0046] As described above, when the first upper limit number N1 of targets that can be subject to light distribution control is equal to or greater than the number T1 of short-distance targets 14, the light distribution control device 6 according to this embodiment controls the light distribution variable lamp 2 to irradiate the short-distance targets 14 with light at an illuminance according to the attributes of the short-distance targets 14. Furthermore, when the remaining number M obtained by subtracting the number T1 of short-distance targets 14 from the first upper limit number N1 is equal to or greater than the number T2 of long-distance targets 16, the light distribution control device 6 controls the light distribution variable lamp 2 to irradiate the long-distance targets 16 with light at an illuminance according to the attributes of the long-distance targets 16.

[0047] That is, in this embodiment, an upper limit (first upper limit number N1) is set for the number of targets for ADB control for the short-range targets 14 and the long-range targets 16. First, if the number T1 of the short-range targets 14 is equal to or less than the first upper limit number N1, ADB control is performed on the short-range targets 14. Next, if the number T2 of the long-range targets 16 is equal to or less than the number of targets (remaining number M) remaining after allocation to the short-range targets 14, ADB control is performed on the long-range targets 16. Therefore, the short-range targets 14 are given priority over the long-range targets 16 in the ADB control. The short-range targets 14 are more likely to affect the traveling of the host vehicle V than the long-range targets 16. Therefore, by giving priority to the ADB control on the short-range targets 14, the visibility of the short-range targets 14 to the driver of the host vehicle V can be improved, thereby improving the safety of vehicle driving.

[0048] Furthermore, when the number T1 of short-range targets 14 exceeds the first upper limit number N1, the light distribution control device 6 determines the illuminance of light to be irradiated onto the short-range targets 14 and the long-range targets 16 without depending on these targets. In other words, it abandons ADB control for the short-range targets 14 and the long-range targets 16. Furthermore, when the number T2 of long-range targets 16 exceeds the remaining number M, it determines the illuminance of light to be irradiated onto the long-range targets 16 without depending on the long-range targets 16. In other words, it abandons ADB control for the long-range targets 16. This makes it possible to prevent the light distribution pattern from switching frequently even if the number of targets subject to ADB control increases. This reduces the risk that the driver of the host vehicle V will feel visual annoyance, and prevents a decrease in the driver's visibility.

[0049] Furthermore, in this embodiment, a second upper limit number N2 of targets that can be subject to light distribution control is set, and the second upper limit number N2 is greater than the first upper limit number N1. When the second upper limit number N2 is equal to or greater than the number S of forward vehicles 12, the light distribution control device 6 controls the variable light distribution lamp 2 to form a light-blocking portion for the forward vehicles 12. The first upper limit number N1 is calculated by subtracting the number S of forward vehicles 12 from the second upper limit number N2. Therefore, the forward vehicles 12 are given priority in the ADB control over the short-range targets 14 and the long-range targets 16. This makes it possible to more reliably reduce the glare imparted to the driver of the forward vehicle 12, thereby improving the safety of vehicle driving.

[0050] Furthermore, when the number S of forward vehicles 12 exceeds the second upper limit number N2, the light distribution control device 6 determines the illuminance of light to be irradiated onto the forward vehicles 12, the short-distance target 14, and the long-distance target 16 without depending on these targets. In other words, ADB control is abandoned for all targets. This further reduces the risk that the driver of the host vehicle V will feel visual annoyance, and suppresses a decrease in the driver's visibility.

[0051] Furthermore, when illuminating a short-distance target 14 with light of an illuminance according to the attribute of the short-distance target 14, the light distribution control device 6 of this embodiment controls the variable light distribution lamp 2 to reduce the illuminance of the light to be irradiated to a high-luminance short-distance target 14. This makes it possible to reduce the glare received by the driver of the host vehicle V from the high-luminance short-distance target 14, thereby improving the safety of vehicle driving. Furthermore, the variable light distribution lamp 2 is controlled to increase the illuminance of the light to be irradiated to a low-luminance short-distance target 14 located on the roadway of the host vehicle V. This makes it easier for the driver of the host vehicle V to see a low-luminance short-distance target 14 within the lane, thereby improving the safety of vehicle driving.

[0052] Low-luminance short-distance targets 14 outside the lane are less likely to affect the traveling of the host vehicle V than high-luminance short-distance targets 14 or low-luminance short-distance targets 14 inside the lane. Therefore, ADB control is not performed for low-luminance short-distance targets 14 outside the lane. In this way, by selecting the short-distance targets 14 to be subject to ADB control, it is possible to reduce the risk of the driver of the host vehicle V feeling visual annoyance and suppress a decrease in visibility for the driver.

[0053] Furthermore, when illuminating the long-distance target 16 with light of an illuminance according to the attribute of the long-distance target 16, the light distribution control device 6 of this embodiment controls the variable light distribution lamp 2 to reduce the illuminance of the light to be irradiated to a high-luminance long-distance target 16. This makes it possible to reduce the glare received by the driver of the host vehicle V from the high-luminance long-distance target 16, thereby improving the safety of vehicle driving. Furthermore, the variable light distribution lamp 2 is controlled to increase the illuminance of the light to be irradiated to a low-luminance long-distance target 16 located on the roadway of the host vehicle V. This makes it easier for the driver of the host vehicle V to see the low-luminance long-distance target 16 within the lane, thereby improving the safety of vehicle driving.

[0054] A low-luminance long-range target 16 outside the lane is less likely to affect the traveling of the host vehicle V than a high-luminance long-range target 16 or a low-luminance long-range target 16 inside the lane. Therefore, ADB control is not performed for a low-luminance long-range target 16 outside the lane. In this way, by selecting the long-range targets 16 to be subject to ADB control, it is possible to reduce the risk of the driver of the host vehicle V feeling visual annoyance and suppress a decrease in visibility for the driver.

[0055] 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.

[0056] The invention according to the above-described embodiment may be specified by the following items. [Item 1] A light distribution control device (6) that controls the light distribution of a variable light distribution lamp (2) according to a target present in a forward area of ​​a vehicle (V), The targets include a short-distance target (14) located within a predetermined distance from the vehicle (V) and a long-distance target (16) located outside the predetermined distance, When a first upper limit number N1 of targets that can be subject to light distribution control is equal to or greater than the number T1 of short-distance targets (14), the light distribution variable lamp (2) is controlled so as to irradiate the short-distance targets (14) with light of an illuminance according to the attributes of the short-distance targets (14); When the remaining number M obtained by subtracting the number T1 of the short-distance targets (14) from the first upper limit number N1 is equal to or greater than the number T2 of the long-distance targets (16), the variable light distribution lamp (2) is controlled so as to irradiate the long-distance targets (16) with light of an illuminance according to the attributes of the long-distance targets (16); When the first upper limit number N1 is less than the number T1 of short-distance targets (14), the variable light distribution lamp (2) is controlled to form a light distribution pattern (PTN, PTN1) that is not dependent on the short-distance targets (14) and the long-distance targets (16), and when the remaining number M is less than the number T2 of long-distance targets (16), the variable light distribution lamp (2) is controlled to form a light distribution pattern (PTN, PTN2) that is not dependent on the long-distance targets (16). Light distribution control device (6). [Item 2] The targets include a vehicle ahead (12), When a second upper limit number N2 of targets that can be subject to light distribution control, which is greater than the first upper limit number N1, is equal to or greater than the number S of forward vehicles (12), the light distribution variable lamp (2) is controlled to form a light blocking portion for the forward vehicles (12), and the first upper limit number N1 is calculated by subtracting the number S of forward vehicles (12) from the second upper limit number N2; When the second upper limit number N2 is less than the number S of the forward vehicles (12), the variable light distribution lamp (2) is controlled to form a light distribution pattern (PTN, Lo) that is independent of the forward vehicles (12), the short-distance target (14), and the long-distance target (16). The light distribution control device (6) according to item 1. [Item 3] When irradiating the short-distance target (14) with light of an illuminance according to the attribute of the short-distance target (14), When the brightness of the short-distance target (14) is equal to or greater than a predetermined value, the variable light distribution lamp (2) is controlled to reduce the illuminance of the light irradiated onto the short-distance target (14); When the luminance of the short-distance target (14) is less than a predetermined value and the short-distance target (14) is located on the travel path of the vehicle (V), the variable light distribution lamp (2) is controlled to increase the illuminance of the light irradiated onto the short-distance target (14). The light distribution control device (6) according to item 1 or 2. [Item 4] When irradiating the long-distance target (16) with light of an illuminance according to the attribute of the long-distance target (16), When the brightness of the long-distance target (16) is equal to or greater than a predetermined value, the variable light distribution lamp (2) is controlled to reduce the illuminance of the light irradiated onto the long-distance target (16); When the brightness of the long-distance target (16) is less than a predetermined value and the long-distance target (16) is located on the travel path of the vehicle (V), the variable light distribution lamp (2) is controlled to increase the illuminance of the light irradiated onto the long-distance target (16). A light distribution control device (6) according to any one of items 1 to 3. [Item 5] a variable light distribution lamp (2) capable of irradiating a forward area with a visible light beam (L1) having a variable intensity distribution; The light distribution control device (6) according to any one of items 1 to 4 is provided. Vehicle lighting system (1). [Item 6] A light distribution control method for controlling the light distribution of a variable light distribution lamp (2) in accordance with a target present in a forward area of ​​a vehicle (V), comprising: The targets include a short-distance target (14) located within a predetermined distance from the vehicle (V) and a long-distance target (16) located outside the predetermined distance, When a first upper limit number N1 of targets that can be subject to light distribution control is equal to or greater than the number T1 of short-distance targets (14), the light distribution variable lamp (2) is controlled so as to irradiate the short-distance targets (14) with light of an illuminance according to the attributes of the short-distance targets (14); When the remaining number M obtained by subtracting the number T1 of the short-distance targets (14) from the first upper limit number N1 is equal to or greater than the number T2 of the long-distance targets (16), the variable light distribution lamp (2) is controlled so as to irradiate the long-distance targets (16) with light of an illuminance according to the attributes of the long-distance targets (16); When the first upper limit number N1 is less than the number T1 of short-distance targets (14), the variable light distribution lamp (2) is controlled to form a light distribution pattern (PTN, PTN1) that is not dependent on the short-distance targets (14) and the long-distance targets (16), and when the remaining number M is less than the number T2 of long-distance targets (16), the variable light distribution lamp (2) is controlled to form a light distribution pattern (PTN, PTN2) that is not dependent on the long-distance targets (16). Light distribution control method. [Industrial Applicability]

[0057] The present invention can be used in a light distribution control device, a vehicle lighting system, and a light distribution control method. [Explanation of symbols]

[0058] 1 Vehicle lighting system, 2 Variable light distribution lamp, 6 Light distribution control device, 12 Forward vehicle, 14 Short-range target, 16 Long-range target.

Claims

1. A light distribution control device that controls the light distribution of a variable light distribution lamp according to a target present in a forward area of ​​a vehicle, The targets include short-distance targets located within a predetermined distance from the vehicle and long-distance targets located outside the predetermined distance, when a first upper limit number N1 of targets that can be subject to light distribution control is equal to or greater than the number T1 of short-distance targets, controlling the variable light distribution lamp so as to irradiate the short-distance targets with light having an illuminance according to an attribute of the short-distance targets; when a remaining number M obtained by subtracting the number T1 of the short-distance targets from the first upper limit number N1 is equal to or greater than the number T2 of the long-distance targets, controlling the variable light distribution lamp to irradiate the long-distance targets with light having an illuminance according to an attribute of the long-distance targets; When the first upper limit number N1 is less than the number T1 of short-distance targets, the variable light distribution lamp is controlled to form a light distribution pattern that is not dependent on the short-distance targets and the long-distance targets, and when the remaining number M is less than the number T2 of long-distance targets, the variable light distribution lamp is controlled to form a light distribution pattern that is not dependent on the long-distance targets. Light distribution control device.

2. The target includes a vehicle ahead, a second upper limit number N2 of targets that can be subject to light distribution control, the second upper limit number N2 being greater than the first upper limit number N1, when the second upper limit number N2 is equal to or greater than the number S of the preceding vehicles, controlling the variable light distribution lamp to form a light blocking portion for the preceding vehicles, and calculating the first upper limit number N1 by subtracting the number S of the preceding vehicles from the second upper limit number N2; When the second upper limit number N2 is less than the number S of the preceding vehicles, the variable light distribution lamp is controlled to form a light distribution pattern that is not dependent on the preceding vehicles, the short-distance target, and the long-distance target. The light distribution control device according to claim 1 .

3. When irradiating the short-distance target with light of an illuminance according to the attribute of the short-distance target, When the luminance of the short-distance target is equal to or greater than a predetermined value, the variable light distribution lamp is controlled to reduce the illuminance of the light irradiated onto the short-distance target; when the luminance of the short-distance target is less than a predetermined value and the short-distance target is located on a roadway of the vehicle, the variable light distribution lamp is controlled to increase the illuminance of the light irradiated onto the short-distance target. The light distribution control device according to claim 1 or 2.

4. When irradiating the long-distance target with light of an illuminance according to the attribute of the long-distance target, When the luminance of the long-distance target is equal to or greater than a predetermined value, the variable light distribution lamp is controlled to reduce the illuminance of the light irradiated onto the long-distance target; when the luminance of the long-distance target is less than a predetermined value and the long-distance target is located on a roadway of the vehicle, controlling the variable light distribution lamp so as to increase the illuminance of the light irradiated onto the long-distance target. The light distribution control device according to claim 1 or 2.

5. a variable light distribution lamp capable of irradiating the forward area with a visible light beam having a variable intensity distribution; The light distribution control device according to claim 1 or 2, Vehicle lighting system.

6. A light distribution control method for controlling a light distribution of a variable light distribution lamp according to a target present in a forward area of ​​a vehicle, comprising: The targets include short-distance targets located within a predetermined distance from the vehicle and long-distance targets located outside the predetermined distance, when a first upper limit number N1 of targets that can be subject to light distribution control is equal to or greater than the number T1 of short-distance targets, controlling the variable light distribution lamp so as to irradiate the short-distance targets with light having an illuminance according to an attribute of the short-distance targets; when a remaining number M obtained by subtracting the number T1 of the short-distance targets from the first upper limit number N1 is equal to or greater than the number T2 of the long-distance targets, controlling the variable light distribution lamp to irradiate the long-distance targets with light having an illuminance according to an attribute of the long-distance targets; When the first upper limit number N1 is less than the number T1 of short-distance targets, the variable light distribution lamp is controlled to form a light distribution pattern that is not dependent on the short-distance targets and the long-distance targets, and when the remaining number M is less than the number T2 of long-distance targets, the variable light distribution lamp is controlled to form a light distribution pattern that is not dependent on the long-distance targets. Light distribution control method.

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