Headlight control device

Abstract

To suppress glare to a vehicle ahead or the like, even in headlights provided on a vehicle with a high ground height or headlights with high illuminance.　Provided is a headlight control device that controls a headlight unit. The headlight control device is provided with: a vehicle-to-vehicle distance acquisition unit that acquires a vehicle-to-vehicle distance (d) between the vehicle and a vehicle traveling ahead of the vehicle; and an irradiation control unit that, when the vehicle-to-vehicle distance falls below a predetermined distance (L1), reduces an irradiation quantity of low beams emitted by the headlight unit.

Description

Headlamp control device

[0001] The present invention relates to a headlamp control device that controls headlamps mounted on a vehicle.

[0002] Headlights mounted on vehicles project light emitted from a light source through an optical system such as a lens toward the front of the vehicle, and can switch between low beam and high beam as needed (see Patent Document 1). The illumination ranges of the low beam and high beam of the headlights are adjusted in accordance with the laws and regulations of the country in which the vehicle equipped with the headlights travels. Generally, the low beam is adjusted so that the upper end of the illumination range (cutoff line) is below the ground clearance of the headlight to prevent glare (dazzle) for preceding and oncoming vehicles, and the high beam is adjusted to illuminate a higher and farther distance than the low beam.

[0003] In a vehicle equipped with headlights, for example, when driving at night, high beams are normally used to ensure visibility for the driver, but when there are vehicles ahead, such as a preceding vehicle or an oncoming vehicle, or pedestrians, low beams are used to reduce glare to the vehicles ahead or pedestrians.

[0004] In addition, when light distribution control is performed on the headlights using ADB (Adaptive Driving Beam), the presence and location of vehicles or pedestrians ahead is identified while driving with high beams, and the headlight illumination range corresponding to the identified location is partially dimmed or turned off to reduce glare on vehicles ahead, etc.

[0005] JP 2019-43260 A

[0006] However, in vehicles with a high vehicle height or vehicles with headlights mounted high above the ground, the headlights are relatively high above the ground, and the illumination range of the low beam and high beam is accordingly higher, which can easily cause glare to vehicles ahead, etc. In particular, headlights that emit a large amount of light and have high illuminance, which have become popular in recent years, are more likely to cause glare to vehicles ahead, etc., due to the high illuminance.

[0007] As mentioned above, low beams limit the illumination range downward by adjusting the upper end of the illumination range to be below the ground clearance of the headlights. However, even with such low beams, glare may be generated on vehicles ahead if the headlights are relatively high above the ground or if the headlights have a high illumination output. On the other hand, adjusting the low beam illumination range downward to offset the high ground clearance of the headlights may reduce the driver's visibility. Furthermore, if the headlight illumination range is located high, even if the ADB partially dims or turns off the headlight illumination range, glare may not be sufficiently suppressed.

[0008] The present invention addresses such a situation by suppressing glare on vehicles ahead, even when using headlights mounted on vehicles with high ground clearance or high illuminance.

[0009] In order to solve the above problems, a light axis adjusting device according to the present invention has the following configuration: That is, one aspect of the present invention provides a headlight control device that controls a headlight unit that irradiates light ahead of a host vehicle, the headlight control device including: an inter-vehicle distance acquisition unit that acquires the inter-vehicle distance between the host vehicle and a preceding vehicle traveling ahead of the host vehicle; and an illumination control unit that reduces the amount of light illuminated in a low beam by the headlight unit when the inter-vehicle distance falls below a predetermined distance L1.

[0010] According to the optical axis adjusting device having such characteristics, even when the headlight is positioned high above the ground, it is possible to optimize the illumination range and reduce glare.

[0011] It is an explanatory diagram showing a schematic configuration of a vehicle control system including a headlamp ECU according to an embodiment of the present invention. It is an explanatory diagram showing a schematic configuration of a headlamp ECU according to an embodiment of the present invention. It is a flowchart showing a control process of a headlamp unit by a headlamp ECU according to an embodiment of the present invention. It is a flowchart showing a control process of a headlamp unit by a headlamp ECU according to a modified embodiment of the embodiment of the present invention.

[0012] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following description, the same reference numerals in different drawings denote parts with the same functions, and duplicated descriptions in each drawing will be omitted as appropriate.

[0013] 1 and 2 , a headlamp ECU (headlamp control device) 11 according to an embodiment of the present invention controls a headlamp unit 21 (described later) attached to a vehicle 100, and functions as part of a vehicle control system 1 mounted on the vehicle 100. The vehicle control system 1 includes a plurality of on-board ECUs (Electronic Control Units) 10 that control various electronic devices required for driving the vehicle 100, and includes a headlamp ECU 11 and an external monitoring ECU 12 as one of the on-board ECUs 10.

[0014] The on-board ECUs 10, headlight ECU 11, external monitoring ECU 12, etc. are connected to each other via an on-board network 3 such as a controller area network (CAN) or a local interconnect network (LIN) so as to be able to communicate with each other, and are also connected to a central gateway (CGW) 4 as a relay device to form a vehicle control system 1. The on-board ECUs 10, headlight ECU 11, and external monitoring ECU 12 are connected to the electronic devices that they control, and control the operation of the connected electronic devices based on information (data) acquired from the on-board network 3. Furthermore, each on-board ECU outputs information indicating the operating state and other status of the connected electronic devices to the on-board network 3.

[0015] Each of the on-board ECUs 10, headlamp ECU 11, and external monitoring ECU 12 may be configured to include, for example, a processor such as a central processing unit (CPU) or a micro processing unit (MPU), electrical circuits, and storage elements such as a random access memory (RAM) or a read-only memory (ROM). Some or all of the operations performed by the on-board ECUs may also be implemented by hardware such as an application specific integrated circuit (ASIC), a field-programmable gate array (FPGA), or a graphics processing unit (GPU). In the following description, detailed descriptions and illustrations of electronic devices not directly involved in the operation of the headlamp ECU 11, the on-board ECU 10, etc. will be omitted.

[0016] The headlamp ECU 11 is connected to a headlamp unit 21 provided in front of the vehicle 100 and controls the headlamp unit 21. The headlamp ECU 11 is also connected to a light axis adjustment unit 22 that adjusts the light axis of the headlamp unit 21 in accordance with instructions from the headlamp ECU 11. Details of the headlamp ECU 11 will be described later.

[0017] The headlamp units 21 are typically provided on the left and right sides of the front of the vehicle, and include a low beam unit 21A that emits a low beam called a passing headlamp, and a high beam unit 21B that emits a high beam called a driving headlamp. The low beam unit 21A and the high beam unit 21B each include a light source such as an LED, a reflector that guides the light emitted from the light source to the front of the vehicle 100, and a lens that irradiates the light emitted from the light source in a predetermined light distribution pattern (none of which are shown).

[0018] In order to reduce glare on vehicles and pedestrians around the vehicle 100, the low beam unit 21A illuminates an area lower than the high beam illumination area and closer to the vehicle 100. Therefore, the low beam illumination area of ​​the low beam unit 21A is set so that it is possible to check for potential obstacles to the traveling of the vehicle 100, such as preceding vehicles and pedestrians located approximately 40 m ahead of the vehicle 100.

[0019] High beam unit 21B irradiates light at a greater illuminance than the low beam illumination range to increase the driver's visibility while driving vehicle 100. Therefore, the illumination range of the high beam emitted by high beam unit 21B is set so that the driver can see any obstacles that may be present in the driving of vehicle 100, such as preceding vehicles or pedestrians located approximately 100 meters ahead of vehicle 100.

[0020] The optical axis adjustment unit 22 includes a drive mechanism such as an electric actuator, and adjusts the optical axis of the low beam unit 21A and the optical axis of the high beam unit 21B by operating the drive mechanism in accordance with instructions from the headlamp ECU 11. The optical axis adjustment unit 22 swings the optical axis of the low beam unit 21A and the optical axis of the high beam unit 21B up and down, changing the angle of each optical axis relative to the horizontal direction, thereby displacing each illumination range.

[0021] The external monitoring ECU 12 constitutes, for example, a part of an ADAS (Advanced Driver-Assistance Systems) that assists the driving of the vehicle 100, and monitors the environment outside the vehicle 100 using a group of sensors including a camera 23, a radar 24, and various other sensors included in the ADAS. That is, the external monitoring ECU 12 outputs, as surrounding information to the in-vehicle network 3, images and various data acquired from the group of sensors described above, or moving objects, structures, road shapes, etc. including pedestrians around the vehicle and other vehicles around the vehicle that are understood from these images and various data, as well as the distances and positional relationships between these and the vehicle.

[0022] The camera 23 is provided, for example, above the windshield of the vehicle 100 and in the center in the vehicle width direction, and captures an image of a predetermined range in front of the vehicle 100. The radar 24 is provided at multiple locations on the vehicle 100, and measures the distance and direction to objects in front of, behind, and to the sides of the vehicle 100, such as other vehicles, pedestrians, and structures, by transmitting radio waves of a predetermined wavelength and receiving the reflected waves.

[0023] (Headlamp ECU) The following describes the headlamp control device, ie, the headlamp ECU 11. The headlamp ECU 11 controls the headlamp unit 21 by referring to information acquired from the above-described in-vehicle ECUs via the in-vehicle network 3.

[0024] As shown in Fig. 2, the headlamp ECU 11 includes a CPU (Central Processing Unit) 111, a ROM 112, and a RAM 113. The CPU 111 executes various processes based on programs stored in the ROM 112. In this embodiment, the CPU 111 loads the programs stored in the ROM 112 into a memory such as the RAM 113 and executes them, thereby functioning as an inter-vehicle distance acquisition unit 121, a light distribution control unit 122, and an illumination control unit 123 shown in Fig. 2. The inter-vehicle distance acquisition unit 121 and the illumination control unit 123 will be described below.

[0025] The inter-vehicle distance acquisition unit 121 acquires the inter-vehicle distance d between the vehicle 100 and a preceding vehicle traveling ahead of the vehicle 100. The preceding vehicle includes an oncoming vehicle traveling in the opposite direction to the traveling direction of the vehicle 100, and a preceding vehicle traveling ahead of the vehicle 100 in the same traveling direction as the vehicle 100.

[0026] The inter-vehicle distance acquisition unit 121 can acquire, for example, from the external monitoring ECU 12, the inter-vehicle distance d, which is the distance between the vehicle 100 and a preceding vehicle, calculated based on an image of a predetermined range ahead of the vehicle 100 captured by the camera 23, or the inter-vehicle distance d measured based on transmitted waves and received waves by the radar 24. The inter-vehicle distance acquisition unit 121 may acquire the image captured by the camera 23 via the external monitoring ECU 12 and perform predetermined image processing on the image to acquire the inter-vehicle distance d.

[0027] The light distribution control unit 122 sets light distribution patterns for the low beam unit 21A and the high beam unit 21B to illuminate their respective illumination ranges, and outputs drive signals according to the set light distribution patterns to the headlamp unit 21. The light distribution control unit 122 can also perform variable light distribution control known as ADB (Adaptive Driving Beam) (hereinafter referred to as ADB control). For example, when the vehicle 100 is traveling with its high beams illuminated and a vehicle ahead is present, the light distribution control unit 122 uses ADB control to set the illumination range of the high beam unit 21B and to set a light distribution pattern that specifies a region within this illumination range that partially dims or blocks light in an area corresponding to the position of the vehicle ahead, etc.

[0028] When the inter-vehicle distance d between the vehicle 100 and the preceding vehicle acquired by the inter-vehicle distance acquisition unit 121 becomes equal to or less than a certain distance, i.e., when the inter-vehicle distance d becomes less than a predetermined distance L1, the illumination control unit 123 controls the headlamp unit 21 to reduce the amount of light emitted by the low beam unit 21A. The predetermined distance L1 can be set arbitrarily, and for example, the predetermined distance L1 can be set to a distance shorter than the distance at which switching from low beam to high beam is performed. In this way, the illumination control unit 123 suppresses glare caused by the high beam when switching from high beam to low beam and illuminating the low beam, and can also suppress glare that may occur when the preceding vehicle approaches the vehicle 100 even closer.

[0029] The illumination control unit 123 can gradually or stepwise reduce the amount of light emitted by the low beam unit 21A according to the inter-vehicle distance d. In other words, the illumination control unit 123 can control the amount of light emitted by the low beam unit 21A to be reduced as the inter-vehicle distance d becomes shorter. In this way, glare on the vehicle ahead can be more effectively suppressed.

[0030] In addition, regardless of whether the aforementioned ADB control is being performed or not, when the inter-vehicle distance d between the vehicle 100 and the vehicle ahead falls below a predetermined distance L1, the illumination control unit 123 controls the headlight unit 21 to reduce the amount of light illuminated by the headlight unit 21.

[0031] The amount of light irradiated by the headlight unit 21 can be determined appropriately based on the ground height of the headlight unit 21 on the vehicle 100, the illumination capacity of the headlight unit 21, etc., and the amount of light irradiated before reduction, the amount of light irradiated to be reduced, the amount of light irradiated after reduction, etc., and stored in the ROM 112 of the headlight ECU 11, for example.

[0032] In addition, the illumination control unit 123 reduces the amount of low beam light emitted when the inter-vehicle distance d falls below a predetermined distance L1, and then controls the headlight unit 21 to return to the amount of light emitted before the change in the following cases.

[0033] When the preceding vehicle is a preceding vehicle traveling ahead of vehicle 100 in the same traveling direction as vehicle 100, and the inter-vehicle distance d between the preceding vehicle and vehicle 100 exceeds a predetermined distance L2, the illumination control unit 123 returns the illumination light intensity to the level before the change. When the preceding vehicle is an oncoming vehicle of vehicle 100, the illumination control unit 123 returns the illumination light intensity to the level before the change after vehicle 100 and the oncoming vehicle have passed each other. In this manner, glare on vehicles ahead of vehicle 100 and the like is suppressed, while ensuring visibility for the driver of vehicle 100.

[0034] The control process for the headlamp unit 21 by the headlamp ECU 11 configured as above will now be described with reference to the flowchart in Figure 3. The vehicle 100 travels in a dark environment, such as at night, while emitting low beam or high beam from the headlamp unit 21 in accordance with the light distribution pattern set by the light distribution control unit 122 of the headlamp ECU 11. In this embodiment, the predetermined distance L1 is set to a distance shorter than the inter-vehicle distance d at which the headlamp is switched from high beam to low beam.

[0035] At this time, in the vehicle 100, the camera 23 captures images ahead of the vehicle 100 at a predetermined cycle, and the radar 24 measures the positional relationship and distance to other vehicles (including the vehicle ahead) and pedestrians present around the vehicle 100 at a predetermined cycle, and outputs the results to the external monitoring ECU 12. Based on the image output from the camera 23 or the measurement results by the radar 24, if there is another vehicle ahead of the vehicle 100, the external monitoring ECU 12 outputs an inter-vehicle distance d indicating the distance between the vehicle 100 and the vehicle ahead.

[0036] In the headlamp ECU 11, the inter-vehicle distance acquisition unit 121 acquires the inter-vehicle distance d from the external monitoring ECU 12 via the in-vehicle network 3 (step S11), and monitors whether the inter-vehicle distance d is less than a predetermined distance L1 (step S12). If the inter-vehicle distance d is less than the predetermined distance L1 (YES in step S12), the inter-vehicle distance acquisition unit 121 notifies the illumination control unit 123 of this fact, and the illumination control unit 123 controls the headlamp unit 21 to reduce the amount of illumination light (step S13).

[0037] At this time, the low beam unit 21A of the headlamp unit 21 is emitting a low beam, and the illumination control unit 123 reduces the illumination intensity of the low beam to a level lower than the current illumination intensity. Even after reducing the illumination intensity, the inter-vehicle distance acquisition unit 121 continues to acquire the inter-vehicle distance d between the vehicle 100 and the forward vehicle (step S14).

[0038] The illumination control unit 123 determines whether the vehicle 100 has passed a preceding vehicle based on the inter-vehicle distance d (step S15), and if the vehicle has not passed another preceding vehicle (NO in step S15), determines whether the inter-vehicle distance d exceeds a predetermined distance L2 (step S16). If the inter-vehicle distance d exceeds the predetermined distance L2 (YES in step S16) or if the vehicle 100 has passed another preceding vehicle (YES in step S15), the illumination control unit 123 is notified of this, and the illumination control unit 123 controls the headlamp unit 21 to return the reduced illumination light intensity to the illumination light intensity before reduction (step S17).

[0039] (Modification) As the light sources of the low beam unit 21A and the high beam unit 21B, for example, a light source unit including a plurality of segments arranged in a matrix and each of which can be independently controlled to light up, or an array light source having a plurality of light-emitting elements arranged in a matrix, can be used. In this case, when the inter-vehicle distance d between the vehicle 100 and the preceding vehicle acquired by the inter-vehicle distance acquisition unit 121 becomes equal to or less than a certain distance, that is, when the inter-vehicle distance d falls below a predetermined distance L1, the light distribution control unit 122 can set a light distribution pattern including the illumination range of the low beam unit 21A and a region within this illumination range that corresponds to the position of the preceding vehicle, etc., as a specific region that is partially dimmed or blocked.

[0040] The illumination control unit 123 outputs a drive signal indicating the lighting state of each segment or each light-emitting element corresponding to the illumination range of the low beam unit 21A to the headlamp unit 21 in accordance with the light distribution pattern set by the light distribution control unit 122. This allows control to partially dim or block light in a specific area of ​​the illumination range of the low beam unit 21A that corresponds to the position of a vehicle ahead, etc.

[0041] Specifically, the illumination control unit 123 controls the headlight unit 21 to reduce the amount of light emitted by each segment or each light-emitting element corresponding to a specific area among the segments or each light-emitting element corresponding to the illumination range of the low beam unit 21A, or controls the headlight unit 21 to change each segment or each light-emitting element corresponding to a specific area from a lit state to a non-lit state.

[0042] The control process for the headlamp unit 21 by the headlamp ECU 11 in this modified example will now be described with reference to the flowchart in Figure 4. The vehicle 100 travels in a dark environment, such as at night, while emitting low beam or high beam from the headlamp unit 21 in accordance with the light distribution pattern set by the light distribution control unit 122 of the headlamp ECU 11. In this modified example, the predetermined distance L1 will also be described as being set to a distance shorter than the inter-vehicle distance d at which the high beam is switched to the low beam.

[0043] At this time, in the vehicle 100, the camera 23 captures images ahead of the vehicle 100 at a predetermined cycle, and the radar 24 measures the positional relationship and distance to other vehicles (including the vehicle ahead) and pedestrians present around the vehicle 100 at a predetermined cycle, and outputs the results to the external monitoring ECU 12. Based on the image output from the camera 23 or the measurement results by the radar 24, if there is another vehicle ahead of the vehicle 100, the external monitoring ECU 12 outputs an inter-vehicle distance d indicating the distance between the vehicle 100 and the vehicle ahead.

[0044] In the headlamp ECU 11, the inter-vehicle distance acquisition unit 121 acquires the inter-vehicle distance d from the external monitoring ECU 12 via the in-vehicle network 3 (step S21), and monitors whether the inter-vehicle distance d is less than a predetermined distance L1 (step S22). If the inter-vehicle distance d is less than the predetermined distance L1 (YES in step S22), the inter-vehicle distance acquisition unit 121 notifies the light distribution control unit 122 and the irradiation control unit 123 of this fact.

[0045] The light distribution control unit 122 sets a light distribution pattern that includes the illumination range of the low beam unit 21A and a specific area within the illumination range that corresponds to the position of a vehicle ahead, etc., to be partially dimmed or blocked (step S23). The illumination control unit 123 controls the headlamp unit 21 in accordance with the light distribution pattern set by the light distribution control unit 122 to reduce the amount of light irradiated onto the specific area or to block light from the specific area (step S24).

[0046] The inter-vehicle distance acquisition unit 121 continues to acquire the inter-vehicle distance d between the vehicle 100 and the preceding vehicle even after reducing the amount of illumination light (step S25). The illumination control unit 123 determines whether the vehicle 100 has passed the preceding vehicle based on the inter-vehicle distance d (step S26), and if the vehicle 100 has not passed the preceding vehicle (NO in step S26), determines whether the inter-vehicle distance d exceeds a predetermined distance L2 (step S27).

[0047] If the inter-vehicle distance d exceeds the predetermined distance L2 (YES in step S27) or if the vehicle 100 passes a vehicle ahead (YES in step S26), the illumination control unit 123 is notified of this, and the illumination control unit 123 controls the headlamp unit 21 to return the amount of light irradiated on the specific area that has been dimmed or blocked to the amount of light irradiated before the dimming or blocking (step S28).

[0048] In this way, by reducing the amount of light irradiated onto a specific area corresponding to the vehicle ahead or by shading the specific area, it is possible to dim or shade areas of the irradiated area that may cause glare to the vehicle ahead, so even for vehicles with headlights that are high above the ground or with headlights that have high illuminance, the illumination range can be optimized to reduce glare to oncoming or preceding vehicles.

[0049] Furthermore, in the case where the vehicle ahead is an oncoming vehicle, if the vehicle 100 and the oncoming vehicle pass each other after the specific area has been dimmed or blocked, the amount of light irradiated to the dimmed or blocked specific area is restored, thereby ensuring visibility for the driver of the vehicle 100. Similarly, in the case where the vehicle ahead is a leading vehicle, if the inter-vehicle distance d exceeds the predetermined distance L2 after the specific area has been dimmed or blocked and a sufficient distance is secured so that the low beam illumination of the vehicle 100 does not cause glare to the leading vehicle, the amount of light irradiated to the dimmed or blocked specific area is restored, thereby ensuring visibility for the driver of the vehicle 100.

[0050] Although the embodiments of the present invention have been described in detail with reference to the drawings, the specific configurations are not limited to these embodiments, and the present invention also includes design changes within the scope of the present invention. Furthermore, the above-described embodiments can be combined by utilizing each other's technologies as long as there are no particular contradictions or problems in their purposes, configurations, etc.

[0051] 1: Vehicle control system, 3: In-vehicle network, 11: Headlight ECU, 12: External monitoring ECU, 21: Headlight unit, 21A: Low beam unit, 21B: High beam unit, 22: Optical axis adjustment unit, 23: Camera, 24: Radar, 121: Inter-vehicle distance acquisition unit, 122: Light distribution control unit, 123: Irradiation control unit

Claims

1. A headlight control device that controls a headlight unit that emits light ahead of a vehicle, comprising: an inter-vehicle distance acquisition unit that acquires the inter-vehicle distance between the vehicle and a preceding vehicle traveling in front of the vehicle; and an illumination control unit that reduces the amount of low beam light illuminated by the headlight unit when the inter-vehicle distance falls below a predetermined distance L1.

2. The headlamp control device according to claim 1, wherein the illumination control unit dims or blocks light in a specific area within the illumination range of the low beam that corresponds to the vehicle ahead.

3. The headlamp control device according to claim 2, wherein the headlamp unit includes an array light source having a plurality of light-emitting elements arranged in a matrix, and the illumination control unit controls the lighting state of the light-emitting elements to dim or block light from the specific area.

4. A headlamp control device as claimed in claim 2, wherein the headlamp unit comprises a light source unit including a plurality of segments each of which can be independently controlled to be lit, and the illumination control unit controls the lighting state of the plurality of segments to dim or block light in the specific area.

5. A headlamp control device as described in any one of claims 1 to 4, wherein the illumination control unit reduces the amount of illumination light gradually or stepwise in accordance with the inter-vehicle distance when the inter-vehicle distance falls below a predetermined distance L1.

6. A headlamp control device as described in any one of claims 1 to 4, wherein, when the forward vehicle is a preceding vehicle traveling ahead of the host vehicle in the same traveling direction as the host vehicle, the illumination control unit returns the reduced illumination light amount to the illumination light amount before the change when the inter-vehicle distance between the preceding vehicle and the host vehicle exceeds a predetermined distance L2.

7. A headlamp control device as described in any one of claims 1 to 4, wherein, when the vehicle ahead is an oncoming vehicle of the host vehicle, the illumination control unit returns the reduced amount of illumination light to the amount of illumination light before the change after the host vehicle and the oncoming vehicle have passed each other.

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