JP5882755B2 - Lighting control device for vehicle headlamp, vehicle headlamp system - Google Patents

Description

  The present invention relates to a technique for controlling an irradiation state of a vehicle headlamp.

  When driving the vehicle at night, the driver basically irradiates the road surface with a low beam with a headlamp, and confirms the front of the vehicle by irradiating a high beam as necessary. However, if light is irradiated above the so-called cut-off line, glare may be imparted to oncoming vehicles and preceding vehicles (hereinafter referred to as “front vehicles”). For this reason, in recent years, various techniques for detecting the position of the vehicle ahead and controlling the irradiation pattern of the high beam so as not to irradiate light to these existing positions and suppressing glare have been proposed (for example, Japanese Patent Application Laid-Open No. 2010-2010). No.-232081). In determining the light-shielding range where the high beam is not irradiated, for example, the front vehicle is photographed by a camera mounted on the host vehicle, and the position of the lamp (tail lamp or head lamp) of the front vehicle is detected using the photographed image. The area where the vehicle ahead is present is set as a light shielding range. The high beam irradiation pattern is configured to be able to individually irradiate a plurality of irradiation areas, and each irradiation area is selectively irradiated according to a set light shielding range. By appropriately controlling the irradiation pattern of the high beam in this way, it is possible to irradiate light to other areas while preventing glare to the vehicle ahead, which contributes to early detection of pedestrians and improvement of distance visibility. be able to.

  By the way, when performing the above light distribution control, the relative positional relationship between the preceding vehicle and the host vehicle may fluctuate, resulting in a situation in which the preceding vehicle enters and exits the boundary between the two irradiation areas of the high beam. is there. For example, when the position of a front vehicle that is relatively far from the host vehicle fluctuates and the right end of the front vehicle enters and exits the boundary between two irradiation areas, the front vehicle This detection / non-detection is repeated, and accordingly, light irradiation / non-irradiation of the right irradiation area frequently occurs. The same applies to the case where there are a forward vehicle that is stably detected relatively far from the host vehicle and a forward vehicle that moves in and out of the irradiation area with the position in the traveling direction fluctuating back and forth in front of the host vehicle. It is. In this case, along with repeated detection / non-detection of the front vehicle obliquely forward, light irradiation / non-irradiation to the irradiation area between this front vehicle and another front vehicle frequently occurs. If light irradiation / non-irradiation occurs frequently as described above, it is not preferable because it gives a visually uncomfortable feeling to the passengers of the own vehicle or other vehicles.

JP 2010-238201

  A specific aspect of the present invention aims to provide a light irradiation technique capable of avoiding frequent occurrence of light irradiation / non-irradiation of a headlamp regardless of the positional relationship between the host vehicle and a preceding vehicle. I will.

A lighting control device for a vehicle headlamp according to an aspect of the present invention is a lighting control device for controlling a light irradiation state by a vehicle headlamp, and (a) a vehicle's headlight photographed by a camera. A vehicle detection unit that detects position information of the preceding vehicle based on a front image; and (b) a vehicle heading arranged along the horizontal direction based on the position information of the preceding vehicle obtained at predetermined intervals. A vehicle presence degree determination unit that determines the presence degree of a preceding vehicle within a certain period for each of a plurality of irradiation areas that are selectively irradiated with light from a lamp; and (c) presence of a preceding vehicle in each of the plurality of irradiation areas select an irradiation area to be light irradiated to set the light distribution pattern corresponding to the degree seen including a light distribution controller for outputting to the headlamp for a vehicle and generates a control signal corresponding to the light distribution pattern, (D) Vehicle presence The determination unit detects the appearance frequency of the front vehicle within a certain period in each of the plurality of irradiation areas, and determines that the presence degree of the front vehicle is relatively low for the irradiation area where the appearance frequency is less than a predetermined reference. (E) The appearance frequency counts at least one of the number of times the detection state of the preceding vehicle has changed from non-detection to detection and the number of times the detection state of the preceding vehicle has changed from detection to non-detection within a certain period. (F) The light distribution control unit selects the irradiation area that is determined by the vehicle presence degree determination unit as having a relatively low presence degree of the preceding vehicle as the irradiation area to be irradiated with light. This is a lighting control device for a vehicle headlamp. Here, the “appearance frequency” means, for example, that the detection state of the preceding vehicle has changed from “detected” to “non-detected” in a certain irradiation area, or conversely changed from “non-detected” to “detected”, or It can detect by detecting the frequency | count of both.

According to the said structure, the presence degree of the front vehicle in a fixed period is determined about each irradiation area, and the irradiation area which should be irradiated with light according to the presence degree is selected. Since the determination is based on the degree of existence within a certain period, even if there is no forward vehicle at a certain timing, there is no immediate switch between light irradiation / non-irradiation to the irradiation area. Even when the relative positional relationship of the vehicle fluctuates, regardless of the positional relationship, frequent occurrence of light irradiation / non-irradiation of the headlamp can be avoided, and the uncomfortable feeling of the passengers of the host vehicle and the preceding vehicle can be reduced. It becomes possible. Moreover, if the appearance frequency of the preceding vehicle within a certain period is less than a predetermined reference, it can be said that the degree of presence of the preceding vehicle in the irradiation area is low, so by selecting the irradiation area as an irradiation area to be irradiated with light. Appropriate irradiation conditions can be obtained.

  In the above vehicle headlamp lighting control device, the vehicle presence degree determination unit detects, for example, the presence or absence of a forward vehicle in each of a plurality of irradiation areas, and the state in which no forward vehicle is present continuously exceeds a predetermined reference. Therefore, it can be determined that the presence degree of the forward vehicle is relatively low with respect to the generated irradiation area. And the light distribution control part can select the irradiation area determined as a relatively low presence degree by the vehicle presence degree determination part as an irradiation area which should be irradiated with light.

  If a state in which no preceding vehicle is present is continuously detected within a certain period, it can be said that the degree of presence of the preceding vehicle in the irradiation area is low, so by selecting the irradiation area as an irradiation area to be irradiated with light. Appropriate irradiation conditions can be obtained.

  It is also preferable that the vehicle presence degree determination unit determines that the appearance frequency is less than a predetermined reference when the number of times the detection state of the preceding vehicle has changed from non-detection to detection is less than three. It is also preferable that the above-mentioned fixed period is at least 10 times the above-mentioned predetermined period.

  The vehicle headlamp described above preferably includes a plurality of light emitting elements, and each of the light emitting elements can be turned on and off individually.

  A vehicle headlamp system according to one aspect of the present invention includes the above-described vehicle headlamp lighting control device and the vehicle headlamp controlled by the lighting control device.

  Thus, a bright vehicle headlamp system capable of avoiding frequent light irradiation / non-irradiation regardless of the positional relationship between the host vehicle and the preceding vehicle is provided.

It is a block diagram which shows the structure of the vehicle headlamp system of one Embodiment. It is a disassembled perspective view which shows the structural example of an optical unit. It is a schematic diagram for demonstrating the specific example of a light distribution pattern. It is a figure which shows the example of a detection of the front vehicle in each irradiation area. It is a flowchart which shows the operation | movement procedure of a vehicle headlamp system. It is a figure for demonstrating an example of the detection state of a front vehicle, the state of the counter corresponding to it, and the lighting / extinguishing state of an irradiation area. It is a flowchart which shows the operation | movement procedure of a vehicle headlamp system. It is a figure for demonstrating an example of the detection state of the front vehicle, its measurement period, the state of the counter corresponding to them, and the lighting-on / off state of an irradiation area. It is a flowchart which shows the operation | movement procedure of a vehicle headlamp system.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 is a block diagram illustrating a configuration of a vehicle headlamp system according to an embodiment. The vehicle headlamp system shown in FIG. 1 performs light irradiation by setting a light distribution pattern based on an image obtained by photographing a space (target space) in front of the host vehicle with a camera 11. A central control unit (lighting control device) 10 and two optical units 15R and 15L connected thereto are provided. The central control unit 10 includes a vehicle detection unit 12, a vehicle presence degree determination unit 13, and a light distribution control unit 14. The central control unit 10 is realized by executing a predetermined operation program in a computer system having, for example, a CPU, a ROM, a RAM, and the like.

  The camera 11 is installed at a predetermined position (for example, in the vicinity of an indoor mirror) of the host vehicle, and captures a space in front of the host vehicle.

  The vehicle detection unit 12 obtains an image (image data) obtained by photographing the space ahead of the host vehicle from the camera 11 and performs image recognition processing on the image, whereby the vehicle ahead (target vehicle). The position information of is detected. The “front vehicle” here is a preceding vehicle or an oncoming vehicle.

  The vehicle presence degree determination unit 13 determines the presence degree of the front vehicle in the front area of the host vehicle based on the position information of the front vehicle detected by the vehicle detection unit 12. In the present embodiment, the front area (area in the image) of the host vehicle is divided into a plurality of irradiation areas in the horizontal direction, and the presence degree of the front vehicle in each irradiation area is determined.

  The light distribution control unit 14 exists in front of the host vehicle based on the position information of the preceding vehicle obtained by the vehicle detection unit 12 and the degree of existence of the preceding vehicle in each irradiation area obtained by the vehicle presence degree determination unit 13. A light distribution pattern having a light shielding range according to the position of the vehicle ahead is set, and a control signal (light distribution control) is sent to each of the optical units 15R and 15L so that light is emitted according to the set light distribution pattern. Signal).

  The optical unit 15R is installed on the front right side of the host vehicle and used to irradiate light that illuminates the front of the host vehicle. Similarly, the optical unit 15L is installed on the front left side of the host vehicle, and is used for irradiating light that illuminates the front of the host vehicle. As shown in the figure, the optical units 15R and 15L have a common configuration. Specifically, each of the optical units 15R and 15L includes a unit-side control unit 21, an LED lighting circuit 22, and nine LEDs (light emitting devices) connected in parallel to each other. Element) 1-9.

  The unit-side control unit 21 receives a control signal (LED lighting / lighting signal) from the light distribution control unit 14 and gives a control signal to the LED lighting circuit 22 to turn on / off the LEDs 1 to 9 and the luminous intensity of each LED. Are controlled individually.

  The LED lighting circuit 22 controls the turning on and off of the LEDs 1 to 9 by individually supplying drive signals (drive currents) to the LEDs 1 to 9 based on the control signal from the light distribution control unit 14. Each luminous intensity is controlled by the magnitude of the current.

  FIG. 2 is an exploded perspective view illustrating a configuration example of the optical unit. As shown in FIG. 2, the optical unit 15R (or 15L) is disposed behind the projection lens 41 disposed on the optical axis AX extending in the vehicle front-rear direction and the rear focal plane of the projection lens 41. The light source unit 30, a lens holding frame 40 that holds the projection lens 41 in a predetermined position, and a heat sink 50 attached to the light source unit 30 are configured. The optical unit 15R is integrated by attaching the projection lens 41 to the lens holding frame 40 and fixing the lens holding frame 40 to the heat sink 50 with screws. The light source unit 30 includes an interference prevention member 32 formed by integrating a plurality of light guide lens portions 31 and a plurality of LEDs arranged in one direction (horizontal direction) and is disposed behind the interference prevention member 32. The light emitting element substrate 33 is included. The LEDs provided on the light emitting element substrate 33 are the LEDs 1 to 9 connected to the LED lighting circuit 22 described above. The light emitted from each LED is guided to the projection lens 41 by each light guide lens portion 31 of the interference preventing member 32 and projected in front of the host vehicle. At this time, the light distribution pattern can be freely controlled by, for example, partially shielding the high beam irradiation area by individually controlling lighting / extinction of each light emitting element.

  FIG. 3A and FIG. 3B are schematic diagrams for explaining a specific example of a light distribution pattern. Specifically, FIG. 3 schematically shows a landscape when looking forward from the host vehicle. In the drawing, a high beam region is arranged on the upper side, and a region not irradiated with light is shown in color. The high beam region includes five irradiation areas a, b, c, d, and e that are selectively irradiated in a line along the horizontal direction. Each irradiation area ae is formed by combining the light irradiated from each of the optical units 15R and 15L. In the example shown in FIG. 3A, the irradiation area c where the vehicle ahead is present in the high beam region is not irradiated with light, and the other irradiation areas a, b, d, and e are irradiated with light. Yes. The example shown in FIG. 3B is a case where the relative positional relationship in the horizontal direction between the preceding vehicle and the host vehicle changes in the high beam region, and a part of the preceding vehicle is in the irradiation area d. The irradiation areas c and d where the vehicle ahead is present are not irradiated with light, and the other irradiation areas a, b and e are irradiated with light.

  Here, when the positional relationship between the preceding vehicle and the host vehicle changes and the preceding vehicle repeatedly enters and exits the irradiation area d at the boundary between the irradiation area c and the irradiation area d, light irradiation to the irradiation area d (FIG. 3). (See (A)) and non-irradiation (see FIG. 3 (B)) are performed many times in succession, giving a sense of discomfort or discomfort to the passengers of the host vehicle or the vehicle ahead. In order to eliminate such inconvenience, the vehicle headlamp system according to the present embodiment detects the degree of presence of a preceding vehicle in each irradiation area, and controls the light distribution pattern using the detection result. FIG. 4 is a diagram illustrating an example of detection of a preceding vehicle in each irradiation area. The vehicle presence degree determination unit 13 detects the presence or absence of the front vehicle for each irradiation area based on the position information of the front vehicle. Here, a flag of “0” is used when a preceding vehicle is detected, and “1” is used when it is not detected. In the detection example shown in FIG. 4, the front vehicle is not detected in the irradiation areas a, b, e (flag = 1), the front vehicle is continuously detected in the irradiation area c (flag = 0), and the front vehicle is in the irradiation area d. Detection (flag = 0) and non-detection (flag = 1) are repeated.

  Hereinafter, the operation of the vehicle headlamp system of the present embodiment will be described in detail. FIG. 5 is a flowchart showing an operation procedure of the vehicle headlamp system.

  Whether the vehicle ahead degree is detected for each irradiation area based on the detection result of the position information of the vehicle ahead by the vehicle detection unit 12 at every fixed period (for example, every 500 milliseconds). Is determined (step ST11).

  The vehicle presence degree determination unit 13 increases the value of the counter c corresponding to the irradiation area by 1 for an irradiation area in which no preceding vehicle is detected (step ST12). On the other hand, the vehicle presence determination unit 13 resets the value of the counter c corresponding to the irradiation area where the vehicle ahead is detected to 0 (step ST13). The irradiation area where the vehicle ahead is detected is immediately turned off (shielded) by the light distribution control unit 14 (step ST16).

  Next, the vehicle presence degree determination unit 13 determines whether or not the value of the counter c corresponding to each irradiation area is equal to or greater than a front vehicle presence / absence confirmation value T (for example, T = 10) that is a predetermined reference value. (Step ST14). In the present embodiment, when the value of the counter c is equal to or greater than T, it is determined that the vehicle is low in the irradiation area corresponding to the counter c, and when the value of the counter c is smaller than T, the counter It is determined that there is a high degree of vehicle presence in the irradiation area corresponding to. That is, the value of the counter c represents the degree of presence of the preceding vehicle.

  Next, the light distribution control unit 14 sets an irradiation area to be shielded in the light distribution pattern based on the determination result by the vehicle presence degree determination unit 13, and each light is irradiated according to the light distribution pattern. A control signal (light distribution control signal) is output to each of the optical units 15R and 15L. Specifically, the light distribution control unit 14 sets a light distribution pattern so that an irradiation area whose counter c is equal to or greater than T is turned on (light irradiation) (step ST15), and the value of the counter c is A light distribution pattern is set so that an irradiation area smaller than T is turned off (shielded) (step ST16).

  FIGS. 6A to 6C are diagrams for explaining an example of the detection state of the preceding vehicle, the state of the counter corresponding to the detection state, and the lighting / lighting state of the light distribution area. For example, the situation (refer FIG. 4) where the front vehicle repeats entering / exiting the irradiation area d (refer FIG. 3) as mentioned above and the presence or absence of a front vehicle is detected corresponding to it is assumed. When the presence / absence of a forward vehicle is detected as shown in FIG. 6A (detection = 0, non-detection = 1), as shown in FIG. 6B, a counter is displayed while no forward vehicle is detected. When the vehicle ahead is detected, the counter is reset to zero. Then, as shown in FIG. 6C, the irradiation area is turned off while the value of the counter is smaller than T, and the irradiation area is turned on when the value of the counter becomes T or more.

  By the way, in above-mentioned embodiment, the presence or absence of the front vehicle was counted for every irradiation area, and when the front vehicle did not exist in a specific irradiation area over a fixed time, the irradiation area was made into the lighting state. On the other hand, the appearance frequency of the preceding vehicle is counted for each irradiation area, and when the preceding vehicle enters and exits at a frequency higher than a certain standard, the irradiation area can be turned off. Hereinafter, an embodiment in this case will be described. FIG. 7 is a flowchart showing an operation procedure of the vehicle headlamp system in this embodiment.

  Whether the vehicle ahead degree is detected for each irradiation area based on the detection result of the position information of the vehicle ahead by the vehicle detection unit 12 at every fixed period (for example, every 500 milliseconds). Is determined (step ST21). The irradiation area where the vehicle ahead is detected is immediately shielded (turned off) (step ST24).

  On the other hand, the vehicle presence degree determination unit 13 determines the number of times that the detection state of the front vehicle has changed from “non-detection to detection” within a certain period in the past (for example, 5 seconds) for an irradiation area in which the front vehicle is not detected (hereinafter referred to as “detection”). , “State change count”) is less than a predetermined reference value (for example, 3 times) (step ST22).

  When the number of state changes of the preceding vehicle is less than the reference value k (step 22; Y), the vehicle presence degree determining unit 13 determines that there is no preceding vehicle in the irradiation area. On the other hand, the vehicle presence degree determination part 13 determines with the front vehicle existing in the irradiation area, when the frequency | count of state change of a front vehicle is more than the reference value k (step 22; N). That is, the number of state changes represents the presence degree of the preceding vehicle.

  Next, the light distribution control unit 14 sets an irradiation area to be shielded in the light distribution pattern based on the determination result by the vehicle presence degree determination unit 13, and each light is irradiated according to the light distribution pattern. A control signal (light distribution control signal) is output to each of the optical units 15R and 15L. Specifically, a light distribution pattern is set so that light irradiation (lights up) is applied to the irradiation area determined by the light distribution control degree determination unit 13 that the front vehicle does not exist (step ST23). Then, a light distribution pattern is set so that the determined irradiation area is shielded (turned off) (step ST24).

  FIG. 8A to FIG. 8D are diagrams for explaining an example of the detection state of the preceding vehicle and its measurement cycle, the state of the counter corresponding to them, and the on / off state of the light distribution area. For example, the situation (refer FIG. 4) where the front vehicle repeats entering / exiting the irradiation area d (refer FIG. 3) as mentioned above and the presence or absence of a front vehicle is detected corresponding to it is assumed. As shown in FIG. 8 (A), when a change in the state of the presence or absence of the preceding vehicle is detected at a constant cycle (500 milliseconds in the example) (detection = 0, non-detection = 1), it is shown in FIG. 8 (B). Thus, the value of the counter is determined as shown in FIG. 8C in accordance with the number of times the front vehicle is detected to be non-detected within a certain past period (in the example, 5 seconds). Then, as shown in FIG. 8D, the irradiation area whose counter value is greater than or equal to the reference value k is turned off, and when the counter value is less than the reference value k, the irradiation area is turned on. .

  Note that the operation procedure shown in FIG. 5 and the operation procedure shown in FIG. 7 can be combined, and an example of the operation procedure in that case will be briefly described below. FIG. 9 is a flowchart showing an operation procedure of the vehicle headlamp system.

  The vehicle presence degree determination unit 13 determines whether or not a forward vehicle is currently detected in the irradiation area based on the detection result by the vehicle detection unit 12 at regular intervals (step ST31).

  The vehicle presence degree determination unit 13 increments the value of the counter c corresponding to the irradiation area by 1 for the irradiation area in which no preceding vehicle is detected (step ST32). On the other hand, for the irradiation area in which the preceding vehicle is detected, the value of the counter c corresponding to the irradiation area is reset to 0 (step ST33), and this irradiation area is immediately turned off (shielded) by the light distribution control unit 14. (Step ST37)

  When the preceding vehicle is not detected, the vehicle presence determination unit 13 determines whether or not the value of the counter c corresponding to each irradiation area is equal to or larger than the preceding vehicle presence / absence confirmation value T that is a predetermined reference value. Determination is made (step ST34).

  When the value of the counter c is equal to or greater than T (step 34; Y), the vehicle presence degree determination unit 13 determines that the degree of presence of the vehicle in the irradiation area corresponding to this counter is low. On the other hand, when the value of the counter c is less than T (step 34; N), the vehicle presence degree determination unit 13 determines that the degree of presence of the vehicle in the irradiation area corresponding to this counter is high, and immediately controls the light distribution. This area is turned off (light-shielded) by the unit 14 (step ST37).

  When it is determined that the degree of presence of the vehicle is low, the vehicle presence degree determination unit 13 counts the number of times that the detection state of the preceding vehicle has changed from “non-detection to detection” for each irradiation area in the past certain period. It is determined whether (number of state changes) is less than a predetermined reference value k (step ST35). When the number of state changes of the preceding vehicle is less than k (step 35; Y), it is determined that there is no preceding vehicle in the irradiation area. On the other hand, the vehicle presence degree determination part 13 determines with the front vehicle existing in the irradiation area, when the state change frequency of a front vehicle is k or more (step 35; N).

  Next, the light distribution control unit 14 sets an irradiation area to be shielded in the light distribution pattern based on the determination result by the vehicle presence degree determination unit 13, and each light is irradiated according to the light distribution pattern. A control signal (light distribution control signal) is output to each of the optical units 15R and 15L. Specifically, the light distribution control unit 14 sets a light distribution pattern so that the irradiation area determined by the vehicle presence degree determination unit 13 that there is no preceding vehicle is irradiated (lighted) (step ST36). ), A light distribution pattern is set so that the irradiation area determined to have a vehicle ahead is shielded (turned off) (step ST37).

  According to the present embodiment as described above, the existence degree of the preceding vehicle is determined for each irradiation area within a certain period, and the irradiation area to be shielded is selected according to the existence degree. Since the determination is based on the degree of existence within a certain period, even if there is no forward vehicle at a certain timing, there is no immediate switch between light irradiation / non-irradiation to the irradiation area. Even when the relative positional relationship of the vehicle fluctuates, regardless of the positional relationship, frequent occurrence of light irradiation / non-irradiation of the headlamp can be avoided, and the uncomfortable feeling of the passengers of the host vehicle and the preceding vehicle can be reduced. It becomes possible.

  In addition, this invention is not limited to the content of embodiment mentioned above, In the range of the summary of this invention, it can change and implement variously. For example, in the above-described embodiment, the number of times the detection state of the preceding vehicle has changed from “non-detection to detection” is counted as the “number of state changes”. The number of times of “change from state to state” may be counted as “the number of times of state change”, or the number of times of both “detection to non-detection” and “non-detection to detection” may be counted as “the number of state changes”. Further, although the light distribution control has been described with an example in which the LED is turned on and off, the light source such as the LED may be turned on, and the area to be turned off may be shielded by the light shielding unit.

1-9: LED
DESCRIPTION OF SYMBOLS 10: Central control part 11: Camera 12: Vehicle detection part 13: Vehicle presence degree determination part 14: Light distribution control part 15R, 15L: Optical unit 21: Unit side control part 22: LED lighting circuit

Claims (5)

A lighting control device for controlling a light irradiation state by a vehicle headlamp,
A vehicle detection unit that detects position information of the preceding vehicle based on an image in front of the host vehicle photographed by the camera;
Based on the position information of the preceding vehicle obtained at predetermined intervals, a certain period for each of a plurality of irradiation areas of light due to the vehicle headlamp are arranged along the horizontal direction are selectively irradiated A vehicle presence degree determination unit for determining the presence degree of the preceding vehicle in
A light distribution pattern is set by selecting an irradiation area to be irradiated with light in accordance with the degree of presence of the preceding vehicle in each of the plurality of irradiation areas, and a control signal corresponding to the light distribution pattern is generated to generate the vehicle Light distribution controller that outputs to the headlamp,
Only including,
The vehicle presence degree determination unit detects an appearance frequency of the front vehicle within a predetermined period in each of the plurality of irradiation areas, and the presence degree of the front vehicle is in an irradiation area where the appearance frequency is less than a predetermined reference. It is judged to be relatively low,
The appearance frequency is obtained by counting at least one of the number of times that the detection state of the preceding vehicle has changed from non-detection to detection and the number of times that the detection state of the preceding vehicle has changed from detection to non-detection within the predetermined period. Sought after,
The light distribution control unit selects, as the irradiation area to be irradiated with light, an irradiation area that is determined by the vehicle presence determination unit to be relatively low in the degree of presence of the preceding vehicle.
Lighting control device for vehicle headlamps. When the number of times that the detection state of the preceding vehicle has changed from non-detection to detection is less than three times, the vehicle presence degree determination unit assumes that the appearance frequency is less than a predetermined reference.
The lighting control device for a vehicle headlamp according to claim 1 . The certain period is at least 10 times the predetermined period;
The lighting control device for a vehicle headlamp according to claim 1 or 2 . The vehicle headlamp is provided with a plurality of light emitting elements and can individually turn on and off the light emitting elements.
The lighting control device for a vehicle headlamp according to any one of claims 1 to 3 . A lighting control device for a vehicle headlamp according to any one of claims 1 to 4,
A vehicle headlamp controlled by the lighting control device,
Including a vehicle headlamp system.