Vehicle headlight
Patent Information
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- KOITO MFG CO LTD
- Filing Date
- 2026-01-16
- Publication Date
- 2026-07-30
Smart Images
Figure JP2026001275_30072026_PF_FP_ABST
Abstract
Description
Vehicle headlamp
[0006]
[0001] The present disclosure relates to a vehicle headlamp.
[0002] Vehicle headlamps that form a low beam light distribution pattern are known. Patent Document 1 discloses that, in order to ensure the visibility of the road surface in front of the vehicle, when the vehicle body rolls toward the forward lane side, the light source bulb is rotated in the direction opposite to the rolling direction to maintain a substantially upright state. As a result, the cut-off line of the low beam light distribution pattern is less likely to tilt downward toward the forward lane side.
[0003] Japanese Patent Application Laid-Open No. 2002-324417
[0004] When one optical unit irradiates light in the region near the lower side of the cut-off line as in Patent Document 1, when the vehicle turns and the vehicle body tilts, the light distribution pattern formed by the optical unit also tilts in the same direction as the direction in which the vehicle body tilts. If such a single tilted light distribution pattern is used so as not to dazzle the vehicle in front in front of the vehicle, it is necessary to lower the entire light distribution pattern downward. However, as the entire light distribution pattern is lowered downward, it becomes difficult to irradiate light far away, and the long-distance visibility deteriorates.
[0005] Therefore, an object of the present disclosure is to provide a vehicle headlamp that is less likely to dazzle a vehicle in front and is less likely to reduce long-distance visibility.
[0006] A vehicle headlight according to one aspect of the present disclosure is a vehicle headlight installed on a vehicle, comprising: a cutoff line extending in the left-right direction; a first left optical unit that irradiates light to an area including at least the area near the lower part of the cutoff line and the area to the left; a first right optical unit that irradiates light to the cutoff line and an area including at least the area near the lower part of the cutoff line and the area to the right; and a second optical unit that can irradiate light to an area including at least the area above the cutoff line and can dim any of the areas therein, wherein when the vehicle is turning and there is a vehicle ahead of the vehicle, the vehicle headlight dims the light from one of the optical units, the first left optical unit and the first right optical unit, which is more likely to cause glare to the vehicle ahead, and increases the light from the other optical unit of the first left optical unit and the first right optical unit.
[0007] According to this disclosure, two optical units are provided, one on the left and one on the right, which illuminate the area near the bottom of the cutoff line. In other words, the illumination area near the bottom of the cutoff line is divided into two. Even if the vehicle body is tilted and the illumination areas of the first left optical unit and the first right optical unit are tilted, both illumination areas are still near the bottom of the cutoff line. Therefore, by dimming the light from one of the optical units that is more likely to cause glare to the vehicle in front, it is possible to reduce the glare to the vehicle in front, and since the light is not turned off, it is still possible to illuminate the area near the bottom of the cutoff line without excessively reducing long-distance visibility. Furthermore, by increasing the light from the other optical unit that is less likely to cause glare to the vehicle in front, the other illumination area near the bottom of the cutoff line is brighter, further improving long-distance visibility.
[0008] According to this disclosure, a vehicle headlight is provided that is less likely to cause glare to vehicles in front and does not reduce long-distance visibility.
[0009] Figure 1 is a block diagram of the vehicle system configuration, including the vehicle headlights. Figure 2 is a cross-sectional view of the vehicle headlights. Figure 3 is a diagram illustrating the various light distribution patterns emitted by the vehicle headlights. Figure 4 is a diagram illustrating the low beam light distribution pattern when the low beams are on. Figure 5 is a diagram illustrating the high beam light distribution pattern when the high beams are on. Figure 6 is a diagram illustrating the high beam light distribution pattern according to a comparative example, when the vehicle is turning and there is a vehicle in front of the vehicle. Figure 7 is a diagram illustrating the high beam light distribution pattern according to the first embodiment, when the vehicle is turning and there is a vehicle in front of the vehicle.
[0010] The embodiments of this disclosure will be described below with reference to the drawings. For the sake of clarity, the description of components having the same reference numeral as those already described in the description of the embodiments will be omitted. Furthermore, the dimensions of the components shown in these drawings may differ from the actual dimensions of the components for the sake of clarity.
[0011] Furthermore, in the description of this embodiment, for the sake of clarity, the terms "left-right direction," "up-down direction," and "front-back direction" may be mentioned as appropriate. These directions are relative directions set for the vehicle headlight 10 illustrated in Figure 2. Here, the "left-right direction" includes the "left direction" and the "right direction," as well as the vehicle width direction of the vehicle on which the vehicle headlight 10 is mounted. The "up-down direction" includes the "up direction" and the "down direction." The "front-back direction" is the front-back direction of the vehicle, and includes the "forward direction" and the "rear direction." The front-back direction is perpendicular to the left-right direction and the up-down direction. In each figure, the symbol U indicates the upward direction. The symbol D indicates the downward direction. The symbol F indicates the forward direction. The symbol B indicates the rear direction. The symbol L indicates the left direction. The symbol R indicates the right direction. The left-right direction is an example of the horizontal direction.
[0012] (First Embodiment) A vehicle headlight 10 according to the first embodiment will be described with reference to Figures 1 to 7. The vehicle headlight 10 is mounted on the front right and front left sides of the vehicle 1, respectively. The vehicle headlight 10 is configured to form a high beam light distribution pattern PH and a low beam light distribution pattern PL.
[0013] Figure 1 is a block diagram of the system configuration of vehicle 1, including the vehicle headlight 10. As illustrated in Figure 1, vehicle 1 includes the vehicle headlight 10, a camera 30, a light switch 40, and a vehicle control unit 50. In addition, vehicle 1 includes a steering device 21 and a bank angle sensor 22.
[0014] A single vehicle headlight 10 comprises a lamp control unit 60, a first left optical unit 70L, a first right optical unit 70R, a second optical unit 80, and a third optical unit 90. Details of the vehicle headlight 10 will be described later.
[0015] The steering device 21 is installed, for example, inside the vehicle 1. The bank angle sensor 22 is configured to detect the tilt angle when the vehicle body 1 is tilted left or right with respect to the vertical line, and to transmit the detected tilt angle information to the vehicle control unit 50. The bank angle sensor 22 is, for example, a gyro sensor. The tilt angle of the vehicle body 1 may be calculated based on image data captured by the camera 30.
[0016] Camera 30 is positioned near the windshield of vehicle 1. Camera 30 is a camera that includes an image sensor such as a CCD (Charge-Coupled Device) or CMOS (Complementary MOS). Camera 30 acquires image data by imaging the area around vehicle 1 (for example, in front of vehicle 1). Camera 30 outputs the image data to vehicle control unit 50.
[0017] The light switch 40 is located near the steering device 21 of the vehicle 1. The light switch 40 is configured to switch the vehicle headlights 10 ON / OFF or to switch the light distribution pattern in response to an operation by the driver of the vehicle 1. When the driver of the vehicle 1 operates the light switch 40, the light switch 40 generates a control signal to illuminate with a light distribution pattern corresponding to the operation and transmits the signal to the vehicle control unit 50.
[0018] The vehicle control unit 50 is configured to control the driving of the vehicle 1. The vehicle control unit 50 is configured to determine the surrounding environment of the vehicle 1 based on surrounding environment information and to transmit the determination result to the lamp control unit 60 of the vehicle headlight 10. The vehicle control unit 50 is composed of, for example, at least one electronic control unit (ECU). The electronic control unit includes, for example, a computer system including one or more processors and one or more memories, and an electronic circuit composed of active elements such as transistors and passive elements.
[0019] The vehicle control unit 50 is configured to perform image analysis on the image data output from the camera 30. The vehicle control unit 50 detects ambient environment information indicating the surrounding environment of the vehicle 1 from the image data and transmits this ambient environment information to the lamp control unit 60 of the vehicle headlight 10. The ambient environment information includes, for example, position information of objects located in front of the vehicle 1 (oncoming vehicles, vehicles ahead, signs, etc.).
[0020] The vehicle control unit 50 transmits a signal to the lamp control unit 60 of the vehicle headlight 10 to control the vehicle headlight 10 based on the control signal from the light switch 40.
[0021] The lamp control unit 60 of the vehicle headlight 10 may have the same hardware configuration as the vehicle control unit 50. The lamp control unit 60 is configured to control the first left optical unit 70L, the first right optical unit 70R, the second optical unit 80, and the third optical unit 90 based on surrounding environment information received from the vehicle control unit 50.
[0022] Next, the details of the vehicle headlight 10 will be described. Figure 2 is a cross-sectional view of the vehicle headlight 10. As illustrated in Figure 2, the vehicle headlight 10 comprises a lamp body 11 having an opening in front of the vehicle headlight 10, and a translucent outer cover 12 that covers the opening of the lamp body 11. Inside the lamp chamber 13 formed by the lamp body 11 and the outer cover 12 are housed a lamp control unit 60, a first left optical unit 70L, a first right optical unit 70R, a second optical unit 80, and a third optical unit 90. The first left optical unit 70L and the first right optical unit 70R are housed in parallel in the left-right direction, and in Figure 2 only the first left optical unit 70L is illustrated.
[0023] The first left optical unit 70L is configured to illuminate a cutoff line extending in the left-right direction and a region that includes at least the area below and near the cutoff line, and the area to the left. Details of the light distribution pattern illuminated by the first left optical unit 70L will be described later.
[0024] The first right optical unit 70R is configured to illuminate a cutoff line extending in the left-right direction and a region that includes at least the area below and near the cutoff line, and the area to the right. Details of the light distribution pattern illuminated by the first right optical unit 70R will be described later.
[0025] The first left optical unit 70L and the first right optical unit 70R each include, for example, a plurality of light sources 71, a reflector 72, and a projection lens 73. The light sources 71 may be composed of, for example, LED (Light Emitting Diode) elements or LD (Laser Diode) elements. The light sources 71 are configured to emit light toward the reflector 72. The reflector 72 is configured to reflect the light emitted from the light sources 71 toward the projection lens 73. The projection lens 73 is, for example, an aspherical lens whose front surface is convex and its rear surface is flat. The projection lens 73 is configured to project the light reflected by the reflector 72 into the front area of the vehicle 1.
[0026] The second optical unit 80 is configured to illuminate a region including at least a region above the cutoff line. Furthermore, the second optical unit 80 can attenuate any region within the region above the cutoff line. In this specification, the term "attenuating" includes blocking at least a portion of the light emitted from one unit and reducing the intensity of the light emitted from one optical unit.
[0027] The second optical unit 80 can, for example, emit an ADB (Adaptive Driving Beam) light distribution pattern. The ADB light distribution pattern is a high beam light distribution pattern PH that does not emit light into areas where objects such as preceding vehicles or oncoming vehicles are present, and it is a light distribution pattern that changes the non-illuminated area depending on the presence and location of such objects.
[0028] The second optical unit 80 includes a light source 81 and a projection lens 82. The light source 81 may be composed of, for example, a plurality of micro-LED light-emitting elements. The lighting state of the plurality of micro-LED light-emitting elements included in the light source 81 can be changed independently of each other. In other words, in the vehicle headlight 10, the lamp control unit 60 can perform ON / OFF control and brightness adjustment for each of the micro-LED light-emitting elements included in the light source 81. The projection lens 82 may have a configuration similar to that of the projection lens 73, for example.
[0029] The third optical unit 90 is configured to emit light so as to overlap with at least a portion of the cutoff line. The third optical unit 90 includes, for example, a light source composed of an LED array. An LED array is, for example, a light source in which a plurality of micro-LED light-emitting elements are arranged in an array. The illumination state of the plurality of micro-LED light-emitting elements included in the third optical unit 90 can be changed independently of each other. In this case, the vehicle headlight 10 can perform ON / OFF control and brightness adjustment for each of the micro-LED light-emitting elements included in the third optical unit 90 using the lamp control unit 60.
[0030] Next, with reference to Figure 3, the first left light distribution pattern P11L emitted from the first left optical unit 70L, the first right light distribution pattern P11R emitted from the first right optical unit 70R, the second light distribution pattern P12 emitted from the second optical unit 80, and the third light distribution pattern P13 emitted from the third optical unit 90 will be described. Figure 3 is a diagram illustrating each light distribution pattern emitted by the vehicle headlight 10. In this embodiment, the case where the vehicle 1 is traveling in the right lane will be described. The first left light distribution pattern P11L, the first right light distribution pattern P11R, the second light distribution pattern P12, and the third light distribution pattern P13 illustrated in Figure 3 are shown projected onto a virtual vertical screen at a predetermined position in front of the vehicle 1 (for example, 25 m in front of the vehicle 1). The light distribution patterns illustrated in the following figures are also shown projected onto a virtual vertical screen at a predetermined position in front of the vehicle 1. Furthermore, Figure 3 shows a V-V line indicating the vertical direction (up and down direction in Figure 3) at the center of the illumination range of the vehicle headlight 10, and an H-H line perpendicular to the V-V line and extending horizontally (left and right direction in Figure 3). Similarly, subsequent diagrams illustrating light distribution patterns also show a V-V line indicating the vertical direction at the center of the illumination range of the vehicle headlight 10, and an H-H line perpendicular to the V-V line and extending horizontally.
[0031] As illustrated in Figure 3, the first left light distribution pattern P11L and the first right light distribution pattern P11R have a cutoff line CL that extends in the left-right direction. The first left light distribution pattern P11L is illuminated by the first left optical unit 70L to a portion of the left side of the cutoff line CL and to a region that includes the area near the bottom of the cutoff line CL and the area to the left (the left portion with downward-sloping diagonal hatching in Figure 3). Similarly, the first right light distribution pattern P11R is illuminated by the first right optical unit 70R to a portion of the right side of the cutoff line CL and to a region that includes the area near the bottom of the cutoff line CL and the area to the right (the right portion with downward-sloping diagonal hatching in Figure 3). The right portion of the first left light distribution pattern P11L may overlap with the left portion of the first right light distribution pattern P11R, or the right end of the first left light distribution pattern P11L may be in contact with the left end of the first right light distribution pattern P11R.
[0032] The left portion of the cutoff line CL illuminated from the first left optical unit 70L and the right portion of the cutoff line CL illuminated from the first right optical unit 70R combine to form the cutoff line CL. In the following description, "cutoff line CL" refers to the cutoff line illuminated by both the first left optical unit 70L and the first right optical unit 70R when vehicle 1 is moving straight.
[0033] The second light distribution pattern P12, together with the first left light distribution pattern P11L and the first right light distribution pattern P11R, forms the so-called high beam light distribution pattern PH. The second light distribution pattern P12 is irradiated by the second optical unit 80 to an area including at least the area above the cutoff line CL (the area with upward-sloping diagonal hatching in Figure 3). In this embodiment, the second optical unit 80 irradiates the ADB light distribution pattern. Therefore, any area in the second light distribution pattern P12 may be attenuated.
[0034] The third light distribution pattern P13 is irradiated by the third optical unit 90 so as to overlap with at least a portion of the cutoff line CL of the first left light distribution pattern P11L and the first right light distribution pattern P11R (the portion with vertical hatching in Figure 3). In this embodiment, the third light distribution pattern P13 together with the first left light distribution pattern P11L and the first right light distribution pattern P11R form the low beam light distribution pattern PL.
[0035] Next, with reference to Figures 4 and 5, the low-beam light distribution pattern PL emitted from the vehicle headlight 10 when the low beam is on, and the high-beam light distribution pattern PH emitted from the vehicle headlight 10 when the high beam is on will be explained. When the low beam is on, it refers to the time when the driver of vehicle 1 performs an operation on the light switch 40 to emit the low-beam light distribution pattern PL. When the high beam is on, it refers to the time when the driver of vehicle 1 performs an operation on the light switch 40 to emit the high-beam light distribution pattern PH. Figure 4 is an example of the low-beam light distribution pattern PL when the low beam is on. Figure 5 is an example of the high-beam light distribution pattern PH when the high beam is on. In this embodiment, the high-beam light distribution pattern PH emitted is an ADB light distribution pattern.
[0036] As illustrated in Figure 4, when the low beam is on, the vehicle headlight 10 illuminates the first left optical unit 70L, the first right optical unit 70R, and the third optical unit 90. This illuminates the low beam light distribution pattern PL, which consists of the first left light distribution pattern P11L, the first right light distribution pattern P11R, and the third light distribution pattern P13. In other words, the low beam light distribution pattern PL in this embodiment includes the third light distribution pattern P13, and the third light distribution pattern P13 is illuminated so as to overlap with the right side portion of the cutoff line CL (the portion of the cutoff line CL that is higher in height). Therefore, the area illuminated by the overlapping first right light distribution pattern P11R and the third light distribution pattern P13 is brighter than the area illuminated only by the first right light distribution pattern P11R and not by the third light distribution pattern P13. Similarly, the area illuminated by the overlapping first left light distribution pattern P11L and the third light distribution pattern P13 is brighter than the area illuminated only by the first left light distribution pattern P11L and not by the third light distribution pattern P13. Thus, the cutoff line of the light distribution pattern PL when the low beam is selected changes in brightness in two stages. Furthermore, if we count from the area that is not illuminated, it can be said that the cutoff line of the light distribution pattern PL when the low beam is selected changes in brightness in three stages.
[0037] As illustrated in Figure 5, when the high beams are on, the vehicle headlight 10 illuminates the first left optical unit 70L, the first right optical unit 70R, and the second optical unit 80. As a result, a high beam light distribution pattern PH, consisting of the first left light distribution pattern P11L, the first right light distribution pattern P11R, and the second light distribution pattern P12, is emitted.
[0038] In the example shown in Figure 5, since there is a preceding vehicle 1B in front of vehicle 1, camera 30 outputs imaging data related to the preceding vehicle 1B to vehicle control unit 50. Vehicle control unit 50 detects surrounding environment information, including the position information of the preceding vehicle 1B, from the imaging data output from camera 30, and transmits this surrounding environment information to lamp control unit 60. Based on the surrounding environment information received from vehicle control unit 50, lamp control unit 60 controls the second optical unit 80 so that light is not emitted toward the preceding vehicle 1B. For this reason, in the example shown in Figure 5, the area around the preceding vehicle 1B is shielded from light. Consequently, when the high beams are on, the area around the preceding vehicle 1B is shielded from light, and the third light distribution pattern P13 is not illuminated, so the portion C11 of the cutoff line CL located below the preceding vehicle 1B shows a clear difference in brightness. In other words, the cutoff line CL is formed by the region illuminated by the first right light distribution pattern P11R and the region not illuminated by the first right light distribution pattern P11R, and the brightness does not change in two steps near the cutoff line CL. If counted from the region not illuminated by light, the cutoff line of the high beam light distribution pattern PH only changes in brightness in two steps. For this reason, the cutoff line CL formed when the low beam light distribution pattern PL is illuminated appears blurred compared to at least a part (in this embodiment, part C11) of the cutoff line CL formed when the high beam light distribution pattern PH (ADB light distribution pattern) is illuminated. Note that a typical low beam light distribution pattern is formed by blocking some of the light, so the difference in brightness of the cutoff line is usually clear. The cutoff line of a typical low beam light distribution pattern does not change in brightness in two steps. For this reason, the cutoff line of the low beam light distribution pattern PL in this embodiment is blurred compared to the cutoff line of a typical low beam light distribution pattern.
[0039] Next, we will explain the case where vehicle 1 is turning and there is a preceding vehicle 1B in front of vehicle 1, and the high beams are on.
[0040] Figure 6 illustrates a comparative example of the high beam light distribution pattern PHZ when vehicle 1 is turning and there is a preceding vehicle 1B in front of vehicle 1. In the comparative example, unlike in this embodiment, there is only one optical unit that irradiates light to the area near the bottom of the cutoff line CL when the high beam is on. In other words, as illustrated in Figure 6, in the comparative example, one comparative light distribution pattern P11Z is irradiated to the area near the bottom of the cutoff line CL.
[0041] As illustrated in Figure 6, when vehicle 1 turns to the right and its body tilts to the right, the comparative light distribution pattern P11Z also tilts to the right. In order to prevent glare to the preceding vehicle 1B with such a tilted comparative light distribution pattern P11Z, the entire comparative light distribution pattern P11Z needs to be lowered. However, lowering the entire comparative light distribution pattern P11Z makes it more difficult to illuminate distant objects. In the example in Figure 6, in particular, it becomes more difficult to illuminate the area to the right front of vehicle 1. As a result, long-distance visibility decreases.
[0042] Therefore, in this embodiment, two optical units, a first left optical unit 70L and a first right optical unit 70R, are provided as optical units that irradiate light into the area near the lower part of the cutoff line CL. Furthermore, in this embodiment, when the vehicle 1 is turning and there is a vehicle 1B in front of the vehicle 1, the vehicle headlight 10 dims the light from one of the optical units, the first left optical unit 70L and the first right optical unit 70R, which is more likely to cause glare to the vehicle 1B, while increasing the light from the other optical unit. Details will be explained below.
[0043] Figure 7 illustrates the high beam light distribution pattern PHA according to the first embodiment when vehicle 1 is turning and there is a preceding vehicle 1B in front of vehicle 1.
[0044] As illustrated in FIG. 7, when the vehicle 1 turns to the right and the vehicle body of the vehicle 1 tilts to the right, the first left light distribution pattern P111L formed by the first left optical unit 70L also tilts to the right. The first left light distribution pattern P111L tilted to the right still irradiates light near the cut-off line CL when the vehicle 1 is going straight. Similarly, when the vehicle 1 turns to the right and the vehicle body of the vehicle 1 tilts to the right, the first right light distribution pattern P111R formed by the first right optical unit 70R also tilts to the right. The first right light distribution pattern P111R tilted to the right also still irradiates light near the cut-off line CL when the vehicle 1 is going straight. The first left light distribution pattern P111L and the first right light distribution pattern P111R tilted to the right are both not irradiated above the H-H line.
[0045] As illustrated in FIG. 7, when there is a preceding vehicle 1B in front of the right side of the vehicle 1, the optical unit that is likely to dazzle the preceding vehicle 1B is the first right optical unit 70R. The optical unit that is unlikely to dazzle the preceding vehicle 1B is the first left optical unit 70L. Whether it is an optical unit that is likely to dazzle the preceding vehicle 1B may be determined by the vehicle control unit 50 analyzing the imaging data captured by the camera 30. For example, when there is a preceding vehicle 1B in front of the vehicle 1, the vehicle control unit 50 may determine that the first right optical unit 70R is an optical unit that is likely to dazzle the preceding vehicle 1B.
[0046] In the present embodiment, the vehicle headlamp 10 dims and irradiates the light from the first right optical unit 70R that is likely to dazzle the preceding vehicle 1B, and brightens and irradiates the light from the first left optical unit 70L that is unlikely to dazzle the preceding vehicle 1B. Here, the first right optical unit 70R is an example of one of the optical units that is likely to dazzle the preceding vehicle 1B among the first left optical unit 70L and the first right optical unit 70R. The first left optical unit 70L is an example of the other optical unit among the first left optical unit 70L and the first right optical unit 70R.
[0047] The details of light dimming and brightening will be described. In the vehicle headlamp 10 of the present embodiment, it is assumed that the voltage values applied to the first left optical unit 70L and the first right optical unit 70R are a predetermined common constant value. Also, it is assumed that the current values applied to the first left optical unit 70L and the first right optical unit 70R are variable. The left normal power corresponding to the case where the first left optical unit 70L is lit without dimming or brightening is obtained by multiplying a constant voltage value applied to the first left optical unit 70L and a left normal current value that is applied to the first left optical unit 70L without reduction or increase. Similarly, the right normal power corresponding to the case where the first right optical unit 70R is lit without dimming or brightening is obtained by multiplying a constant voltage value applied to the first right optical unit 70R and a right normal current value that is applied to the first right optical unit 70R without reduction or increase.
[0048] Here, for the sake of brief explanation, it is assumed that the light source 71 of the first left optical unit 70L and the light source 71 of the first right optical unit 70R are the same LED element. Further, the number of light sources 71 of the first left optical unit 70L and the number of light sources 71 of the first right optical unit 70R are also the same, both being five.
[0049] When the first right optical unit 70R dims and irradiates light, a constant voltage value and a right reduction current value for lighting the five LED elements in a dimmed state are applied to the first right optical unit 70R. The right reduction current value is lower than the right normal current value. For example, when the right normal current value is 100, the right reduction current value is 80. The right reduction power supplied when the first right optical unit 70R dims and irradiates light is obtained by multiplying the constant voltage value and the right reduction current value. Since the voltage value is constant and the right reduction current value is lower than the right normal current value, the right reduction power is lower than the right normal power.
[0050] As the power supplied to the first right optical unit 70R decreases, less light is emitted from the first right optical unit 70R, and the first right light distribution pattern P111R emitted from the first right optical unit 70R becomes dimmer. The first right optical unit 70R is supplied with reduced right power, which is lower than the normal right power. As a result, the first right light distribution pattern P111R emitted from the first right optical unit 70R, as illustrated in Figure 7, is dimmer than the first right light distribution pattern P11R emitted from the first right optical unit 70R, as illustrated in Figure 3.
[0051] Furthermore, the surplus power on the right, obtained by subtracting the reduced power on the right from the normal power on the right, is supplied to the first left optical unit 70L.
[0052] When the first left optical unit 70L increases its brightness and emits light, a constant voltage value and a left-increasing current value that increases the brightness and lights up the five LED elements are applied to the first left optical unit 70L. The left-increasing current value is higher than the left-normal current value. For example, if the left-normal current value is 100, the left-increasing current value is 120. The left-increasing power supplied when the first left optical unit 70L increases its brightness and emits light is determined by multiplying the constant voltage value and the left-increasing current value. Since the voltage value is constant and the left-increasing current value is higher than the left-normal current value, the left-increasing power is higher than the left-normal power. More specifically, the left-increasing power is higher than the left-normal power by the amount of right-surplus power supplied from the first right optical unit 70R.
[0053] The more power supplied to the first left optical unit 70L, the more light is emitted from the first left optical unit 70L, and the brighter the first left light distribution pattern P111L emitted from the first left optical unit 70L becomes. The first left optical unit 70L is supplied with increased left power, which is higher than the normal left power. In other words, the first left optical unit 70L is supplied with not only normal left power but also excess right power. The voltage value is constant, the light source 71 of the first left optical unit 70L and the light source 71 of the first right optical unit 70R are the same LED elements, and the number of light sources 71 of the first left optical unit 70L and the number of light sources 71 of the first right optical unit 70R are also the same. For this reason, the first right light distribution pattern P111R emitted from the first right optical unit 70R becomes dimmer, while the first left light distribution pattern P111L emitted from the first left optical unit 70L becomes brighter. Thus, the first left light distribution pattern P111L irradiated from the first left optical unit 70L, as illustrated in Figure 7, becomes brighter than the first left light distribution pattern P11L irradiated from the first left optical unit 70L, as illustrated in Figure 3.
[0054] As explained above, in this embodiment, two optical units, the first left optical unit 70L and the first right optical unit 70R, are provided on the left and right sides as optical units that irradiate light into the area near the lower part of the cutoff line CL. In other words, the irradiation area near the lower part of the cutoff line CL is divided into two. Even if the vehicle 1 turns and the first left light distribution pattern P111L from the first left optical unit 70L and the first right light distribution pattern P111R from the first right optical unit 70R are tilted, both light distribution patterns are near the cutoff line CL as when the vehicle 1 is traveling straight. The vehicle headlight 10 reduces the amount of light emitted from the first right optical unit 70R, which is likely to cause glare to the vehicle in front 1B, thereby reducing the amount of glare to the vehicle in front 1B. At this time, the first right optical unit 70R does not turn off, so the vehicle headlight 10 can continue to illuminate the area below the cutoff line CL with light from the first right optical unit 70R, preventing excessive reduction in long-distance visibility. Furthermore, the first left optical unit 70L, which is less likely to cause glare to the preceding vehicle 1B, can utilize the surplus power from the right to increase the brightness of its light, thereby illuminating a brighter first left light distribution pattern P111L and further improving long-distance visibility.
[0055] Furthermore, the greater the turn of the vehicle 1, the greater the amount of dimming change in the optical units that dim the light and emit light, among the first left optical unit 70L and the first right optical unit 70R. In the example of Figure 7, the greater the turn of the vehicle 1 to the right, the less right-reduction power is supplied to the first right optical unit 70R. Whether or not the vehicle 1 is turning sharply can be determined by the vehicle control unit 50 receiving the tilt angle information of the vehicle 1 detected by the bank angle sensor 22, or by the vehicle control unit 50 receiving the imaging data from the camera 30. Since the voltage value applied to the first right optical unit 70R is constant, the greater the turn of the vehicle 1 to the right, the smaller the current value applied to the first right optical unit 70R becomes, and the amount of reduction change, which is the difference from the normal right current value, also becomes larger. For example, if the normal right current value is 100, the right-reduction current value when the vehicle 1 turns slightly is 80, and the right-reduction current value when the vehicle 1 turns sharply is 70. When vehicle 1 makes a small turn, the difference (decrease in change) between the normal current value and the reduced current value is 20, whereas when vehicle 1 makes a large turn, the difference (decrease in change) is 30. Thus, the larger the turn vehicle 1 makes, the larger the decrease in change.
[0056] The sharper the turn of vehicle 1, the greater the tilt of the first right light distribution pattern P111R, making it easier to cause glare to the preceding vehicle 1B and reducing long-distance visibility. However, according to this embodiment, the sharper the turn of vehicle 1, the greater the amount of dimming change of the first right optical unit 70R that dims the light and emits light. This makes it less likely to cause glare to the preceding vehicle 1B and prevents excessive reduction in long-distance visibility.
[0057] Of the first left optical unit 70L and the first right optical unit 70R, the optical unit that is more likely to cause glare to the preceding vehicle 1B may emit light at a reduced brightness such that the illuminated area gradually becomes darker. In the example of Figure 7, the first right optical unit 70R, which is more likely to cause glare to the preceding vehicle 1B, emits light at a reduced brightness such that the first right light distribution pattern P111R gradually becomes darker. Here, "gradually becoming darker" includes at least one of the following: the brightness of the light distribution pattern decreasing linearly or in a straight line over time, or decreasing nonlinearly or in an arbitrary curved line.
[0058] According to this embodiment, the first right optical unit 70R, which is prone to causing glare to the preceding vehicle 1B, dims the light so that the first right light distribution pattern P111R gradually becomes darker. As a result, the brightness of the first right light distribution pattern P111R changes relatively slowly, making it less likely to cause discomfort to the occupants of vehicle 1.
[0059] Of the first left optical unit 70L and the first right optical unit 70R, the dimming time for one optical unit, which is more likely to cause glare to the preceding vehicle 1B, to switch from the normal state to the dimmed state may be shorter than the brightening time for the other optical unit to switch from the normal state to the brightened state. The dimming time for switching from the normal state to the dimmed state refers to the time required from the normal state before one optical unit dims and emits light until that optical unit reaches the dimmed state where it dims and emits light. The brightening time for switching from the normal state to the brightened state refers to the time required from the normal state before the other optical unit brightens and emits light until that optical unit brightens and emits light. In the example in Figure 7, the dimming time of the first right optical unit 70R, which is more likely to cause glare to the preceding vehicle 1B, is shorter than the brightening time of the first left optical unit 70L, which is less likely to cause glare to the preceding vehicle 1B. In this case, the first right light distribution pattern P111R, illuminated from the first right optical unit 70R, dims relatively quickly, while the first left light distribution pattern P111L, illuminated from the first left optical unit 70L, brightens relatively slowly.
[0060] In some cases, reducing glare to the preceding vehicle 1B may take precedence over improving long-distance visibility. According to this embodiment, the dimming time of the first right optical unit 70R, which is prone to dazzling the preceding vehicle 1B, is shorter than the brightening time of the first left optical unit 70L, which is less prone to dazzling the preceding vehicle 1B. Because the first right optical unit 70R, which is prone to dazzling the preceding vehicle 1B, dims relatively quickly and emits light, it is less likely to cause glare to the preceding vehicle 1B.
[0061] Furthermore, the greater the turn of vehicle 1, the greater the increase in the optical unit that amplifies light and emits light among the first left optical unit 70L and the first right optical unit 70R. In the example in Figure 7, the greater the turn of vehicle 1 to the right, the greater the left increase power supplied to the first left optical unit 70L. Since the voltage value applied to the first left optical unit 70L is constant, the greater the turn of vehicle 1 to the right, the greater the current value applied to the first left optical unit 70L, and the larger the increase in the value, which is the difference from the normal left current value. For example, if the normal left current value is 100, the left increase current value when vehicle 1 makes a small turn is 120, and the left increase current value when vehicle 1 makes a large turn is 130. The difference (increase in value) between the normal left current value and the left increase current value when vehicle 1 makes a small turn is 20, while the difference (increase in value) between the normal left current value and the left increase current value when vehicle 1 makes a large turn is 30. Thus, the greater the turn of vehicle 1, the larger the increase in value.
[0062] The more sharply the vehicle 1 turns, the greater the tilt of the first left light distribution pattern P111L, which tends to reduce long-distance visibility. However, according to this embodiment, the greater the sharper the vehicle 1 turns, the greater the increase in the amount of light emitted by the first left optical unit 70L, thus improving long-distance visibility.
[0063] Of the first left optical unit 70L and the first right optical unit 70R, the optical unit that is less likely to cause glare to the preceding vehicle 1B may increase its brightness and emit light so that the illuminated area gradually becomes brighter. In the example of Figure 7, the first left optical unit 70L, which is less likely to cause glare to the preceding vehicle 1B, increases its brightness and emits light so that the first left light distribution pattern P111L gradually becomes brighter. Here, "gradually becoming brighter" includes at least one of the following: the brightness of the light distribution pattern increases linearly or in a straight line over time, or increases nonlinearly or in an arbitrary curved line.
[0064] According to this embodiment, the first left optical unit 70L, which is less likely to cause glare to the preceding vehicle 1B, increases its brightness so that the first left light distribution pattern P111L gradually becomes brighter, thus the brightness of the first left light distribution pattern P111L changes relatively slowly, which is less likely to cause discomfort to the occupants of vehicle 1.
[0065] Furthermore, the vehicle headlight 10 of this embodiment includes a third optical unit 90 that emits light so as to overlap with at least a portion of the cutoff line CL. When the low beam is on, the first left optical unit 70L, the first right optical unit 70R, and the third optical unit 90 are illuminated. In other words, when the low beam is on, the third optical unit 90 emits light so as to overlap with the cutoff line CL formed by the first left optical unit 70L and the first right optical unit 70R. As a result, a low beam light distribution pattern is formed that is blurred and has good visibility compared to the cutoff line CL formed by the first left optical unit 70L and the first right optical unit 70R. On the other hand, when the high beam is on, a so-called ADB light distribution pattern is emitted, and a clear cutoff line is formed, but since the cutoff line only appears in the dimmed area, it does not easily worsen visibility.
[0066] In the embodiment described above, the case where vehicle 1 turns to the right was explained, but the same applies when vehicle 1 turns to the left.
[0067] In the embodiment described above, the case where there is a preceding vehicle 1B to the right front of vehicle 1 was explained, but the same applies when there is an oncoming vehicle to the left front of vehicle 1. When there is an oncoming vehicle to the left front of vehicle 1, the optical unit that is likely to cause glare to the oncoming vehicle is the first left optical unit 70L, and the optical unit that is less likely to cause glare to the oncoming vehicle is the first right optical unit 70R. The vehicle headlight 10 dims the light from the first left optical unit 70L, which is likely to cause glare to the oncoming vehicle, and illuminates the light from the first right optical unit 70R, which is less likely to cause glare to the oncoming vehicle, by increasing the light. Because the vehicle headlight 10 dims the light from the first left optical unit 70L, which is likely to cause glare to the oncoming vehicle, it is less likely to cause glare to the oncoming vehicle, and it is possible to avoid excessively reducing long-distance visibility by still illuminating the area near the bottom of the cutoff line CL. Furthermore, in the vehicle headlight 10, the first right optical unit 70R, which is less likely to cause glare to oncoming vehicles, increases the brightness of its light, thereby brightly illuminating other illumination areas near the lower part of the cutoff line CL, and further improving long-distance visibility.
[0068] In the embodiments described above, the light source 71 of the first left optical unit 70L and the light source 71 of the first right optical unit 70R were the same LED element, but these light source elements may be different from each other. In the embodiments described above, the number of light source 71s of the first left optical unit 70L and the number of light source 71s of the first right optical unit 70R were the same, but these light source numbers may be different from each other. Even if the light source elements are different from each other or the number of light source numbers are different, the reduced power of one optical unit that is more likely to cause glare to the preceding vehicle 1B can be determined by multiplying a certain voltage value by a reduced current value that causes the one optical unit to dim and light up. Furthermore, the surplus power obtained by subtracting the reduced power from the normal power of one optical unit can be supplied to the other optical unit that is less likely to cause glare to the preceding vehicle 1B.
[0069] In the embodiments described above, the decrease in change was explained as 20 or 30, but the decrease in change is not limited to these values. The increase in change was explained as 20 or 30, but the increase in change is not limited to these values. The decrease in change may be the same as or different from the increase in change. For example, the absolute value of the increase in change may be smaller than the absolute value of the decrease in change.
[0070] In the embodiment described above, the current values applied to the first left optical unit 70L and the first right optical unit 70R were changed, but the control of power supply is not limited to this. The lamp control unit 60 of the vehicle headlight 10 may be configured to individually supply an electrical signal (for example, a PWM (Pulse Width Modulation) signal) to each of the plurality of light source elements provided in each optical unit. In this case, the lamp control unit 60 can individually select the light source elements to which the electrical signal is supplied, and can adjust the duty cycle of the electrical signal for each light source element. In other words, the lamp control unit 60 can select the light-emitting elements to be lit or turned off from among the plurality of light source elements, and can change the brightness of each lit light source element. By changing the duty cycle by such PWM control, the surplus power from one optical unit that is more likely to cause glare to the preceding vehicle 1B can be supplied to the other optical unit that is less likely to cause glare to the preceding vehicle 1B.
[0071] In the embodiment described above, two optical units, a first left optical unit 70L and a first right optical unit 70R, were provided as optical units that irradiate light to the area near the bottom of the cutoff line CL. However, the number of such optical units is not limited to two. There may be three or four optical units that irradiate light to the area near the bottom of the cutoff line CL. For example, the vehicle headlight 10 may further include a first central optical unit in addition to the first left optical unit 70L and the first right optical unit 70R. The first central optical unit is configured to irradiate light to the area between the first left light distribution pattern P11L irradiated by the first left optical unit 70L and the first right light distribution pattern P11R irradiated by the first right optical unit 70R, and includes the area near the bottom of the cutoff line CL. When vehicle 1 is turning and there is a vehicle ahead of vehicle 1, the light from at least one of the optical units among the first left optical unit 70L, the first right optical unit 70R, and the first central optical unit, which is likely to cause glare to the vehicle ahead, may be dimmed and illuminated, while the light from the other optical units may be dimmed and illuminated. This configuration also produces the same technical effect.
[0072] In the embodiment described above, when the high beams are on and there are no objects to block the light, such as the preceding vehicle 1B, the third optical unit 90 may be illuminated.
[0073] In the embodiment described above, the vehicle headlight 10 was equipped with a plurality of optical units: a first left optical unit 70L, a first right optical unit 70R, a second optical unit 80, and a third optical unit 90. However, the configuration of the vehicle headlight 10 is not limited to this. The vehicle headlight 10 may be equipped with a single optical unit, and this single optical unit may be provided with the optical system of the first left optical unit 70L, the optical system of the first right optical unit 70R, the optical system of the second optical unit 80, and the optical system of the third optical unit 90.
[0074] The configurations described in each of the following items also constitute part of this disclosure. Item 1: A vehicle headlight provided on a vehicle, comprising: a cutoff line extending in the left-right direction; a first left optical unit that illuminates a region including a region to the left of at least the area near the lower part of the cutoff line; a first right optical unit that illuminates the cutoff line including a region to the right of at least the area near the lower part of the cutoff line; and a second optical unit capable of illuminating a region including a region above at least the cutoff line, and capable of dimming any of the regions therein, wherein when the vehicle is turning and there is a vehicle ahead of the vehicle, the vehicle headlight dims the light from one of the optical units, the first left optical unit and the first right optical unit, which is more likely to cause glare to the vehicle ahead, and increases the light from the other optical unit of the first left optical unit and the first right optical unit. Item 2: A vehicle headlight according to Item 1, wherein the amount of dimming of the optical unit that dims and emits light among the first left optical unit and the first right optical unit increases as the vehicle makes a sharp turn. Item 3: A vehicle headlight according to Item 1 or 2, wherein one of the first left optical unit and the first right optical unit, which is more likely to cause glare to the vehicle in front, dims and emits light such that the illumination area gradually becomes darker. Item 4: A vehicle headlight according to any one of Items 1 to 3, wherein the dimming time for one of the first left optical unit and the first right optical unit, which is more likely to cause glare to the vehicle in front, to switch from a normal state to a dimmed state is shorter than the brightness-enhancing time for the other optical unit to switch from a normal state to a brightness-enhancing state. Item 5: A vehicle headlight according to any one of Items 1 to 4, wherein the amount of brightness-enhancing change of the optical unit that brightens and emits light among the first left optical unit and the first right optical unit increases as the vehicle makes a sharp turn. Item 6: A vehicle headlight according to any one of items 1 to 5, wherein the other optical unit of the first left optical unit and the first right optical unit emits light by increasing the brightness such that the illumination area gradually becomes brighter.Item 7: A vehicle headlight according to any one of items 1 to 6, further comprising a third optical unit that emits light so as to overlap with at least a portion of the cutoff line, wherein when the low beam is on, the first left optical unit, the first right optical unit, and the third optical unit are illuminated.
[0075] This application claims priority under Japanese application No. 2025-009072 filed on 22 January 2025, and incorporates all the provisions contained in the said Japanese application.
Claims
1. A vehicle headlight provided on a vehicle, comprising: a cutoff line extending in the left-right direction; a first left optical unit that illuminates a region including the left region, at least in the vicinity below the cutoff line; a first right optical unit that illuminates the cutoff line and a region including the right region, at least in the vicinity below the cutoff line; and a second optical unit capable of illuminating a region including at least the region above the cutoff line, and capable of dimming any region therein, wherein when the vehicle is turning and there is a vehicle ahead of the vehicle, the vehicle headlight dims the light from one of the optical units, the first left optical unit and the first right optical unit, which is more likely to cause glare to the vehicle ahead, and increases the light from the other optical unit, the first left optical unit and the first right optical unit.
2. The vehicle headlight according to claim 1, wherein the greater the turning of the vehicle, the greater the amount of dimming change of the optical unit that dims and emits light among the first left optical unit and the first right optical unit.
3. Of the first left optical unit and the first right optical unit, the optical unit that is more likely to cause glare to the preceding vehicle emits light by dimming the light so that the illuminated area gradually becomes darker, as described in claim 1.
4. The vehicle headlight according to claim 1, wherein, of the first left optical unit and the first right optical unit, the dimming time for one optical unit which is more likely to cause glare to the preceding vehicle to switch from the normal state to the dimmed state is shorter than the dimming time for the other optical unit to switch from the normal state to the dimmed state.
5. The vehicle headlight according to claim 1, wherein the greater the turning of the vehicle, the greater the amount of change in the brightness of the optical unit that brightens and emits light among the first left optical unit and the first right optical unit.
6. The headlight for a vehicle according to claim 1, wherein the other optical unit of the first left optical unit and the first right optical unit emits light by increasing its brightness so that the illumination area gradually becomes brighter.
7. A vehicle headlight according to any one of claims 1 to 6, further comprising a third optical unit that emits light so as to overlap with at least a portion of the cutoff line, wherein when the low beam is illuminated, the first left optical unit, the first right optical unit, and the third optical unit are illuminated.