Vehicle headlight

Abstract

This vehicle headlight (10) comprises: a cut-off line (CL); a first optical unit (70) that irradiates a region including a region below the cut-off line (CL) with light; a second optical unit (80) that can dim any region in a region above the cut-off line (CL); and a third optical unit (90) that emits light so as to overlap at least a portion of the cut-off line (CL). The vehicle headlight (10) turns on the first optical unit (70) and the second optical unit (80) when a high beam is turned on, and turns on the first optical unit (70) and the third optical unit (90) when a low beam is turned on. The first optical unit (70) emits light such that an irradiation region, which is a portion below the cut-off line (CL) and is irradiated with light reflected by a road surface in front of the vehicle, is darker than the other portions of the irradiation region.

Description

Vehicle headlamp

[0001] The present disclosure relates to a vehicle headlamp.

[0002] A vehicle headlamp that forms a low-beam light distribution pattern is known. When driving in rainy weather, a part of the light emitted as a low-beam light distribution pattern from the vehicle headlamp is reflected by the road surface in front of the vehicle, and may cause glare to oncoming vehicles or the like.

[0003] Patent Document 1 discloses a vehicle headlamp provided with a liquid crystal shutter in order to suppress glare to oncoming vehicles during rainy weather driving. The liquid crystal shutter includes a pair of transparent substrates, a liquid crystal member disposed between the pair of transparent substrates, and a pair of polarizing plates disposed outside the pair of transparent substrates. The liquid crystal member is disposed only in a first region and a second region between the pair of transparent substrates, and the pair of polarizing plates are disposed only in regions corresponding to the regions where the liquid crystal member is disposed on the outer surfaces of the pair of transparent substrates. The pair of polarizing plates disposed corresponding to the second region are formed to have a lower degree of polarization than the pair of polarizing plates disposed corresponding to the first region, and are configured to reduce the light contributing to road surface reflection.

[0004] Japanese Patent Application Laid-Open No. 2011-233305

[0005] Although the vehicle headlamp of Patent Document 1 suppresses glare due to road surface reflection during rainy weather driving, it may also cause glare to a vehicle in front or the like due to road surface reflection even during sunny weather driving.

[0006] Also, from the viewpoint of not causing glare to a vehicle in front or an oncoming vehicle, etc., the cut-off line of the low-beam light distribution pattern is preferably clear in terms of light and darkness. On the other hand, when the driver wants to see a dark area in the distance, if the contrast ratio between light and darkness is too large, the dark area becomes difficult to see, so a cut-off line with a gentle gradient between light and darkness is preferable.

[0007] Therefore, an object of the present disclosure is to provide a vehicle headlamp that forms a light distribution pattern that is difficult to cause glare to a vehicle in front or the like even during sunny weather driving and has good visibility.

[0008] A vehicle headlight according to one aspect of the present disclosure comprises: a cutoff line; a first optical unit that irradiates light to an area including at least an area below the cutoff line; a second optical unit that can irradiate light to an area including at least an area above the cutoff line and can dim any area thereof; and a third optical unit that irradiates light so as to overlap at least a portion of the cutoff line, wherein when the high beam is on, the first optical unit and the second optical unit are lit; when the low beam is on, the first optical unit and the third optical unit are lit; and the first optical unit irradiates light to a portion of the illumination area below the cutoff line such that the illumination area where light reflected from the road surface in front of the vehicle is irradiated is darker than other portions of the illumination area.

[0009] According to this disclosure, when the low beam is illuminated, the third optical unit illuminates the area so as to overlap with the cutoff line formed by the first optical unit. As a result, a low beam light distribution pattern is formed that is blurred and has good visibility compared to the cutoff line formed by the first optical unit alone.

[0010] On the other hand, when the high beams are on, a so-called ADB (Adaptive Deposition) light distribution pattern is projected, forming a distinct cutoff line. However, since the cutoff line only appears in the dimmed area, it does not significantly worsen visibility.

[0011] Furthermore, according to this disclosure, the first optical unit illuminates a portion of the illumination area below the cutoff line, such that the illumination area contributing to road surface reflection is darker than other portions of the illumination area. Since the illumination area contributing to road surface reflection receives less light than other portions of the illumination area, it is possible to reduce glare to vehicles ahead due to road surface reflection.

[0012] According to this disclosure, a vehicle headlight is provided that is less likely to cause glare to vehicles ahead, even when driving in sunny conditions, and that forms a light distribution pattern with good visibility.

[0013] 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 luminous intensity of some of the first light distribution patterns in the first embodiment. Figure 7 is a diagram illustrating the luminous intensity of some of the first light distribution patterns in the second embodiment. Figure 8 is a diagram illustrating the luminous intensity of some of the first light distribution patterns in a modified example of the second embodiment. Figure 9 is a diagram illustrating the luminous intensity of some of the first light distribution patterns in the third embodiment. Figure 10 is a cross-sectional view of the first optical unit according to the fourth embodiment. Figure 11 is a diagram illustrating the luminous intensity of the first light distribution pattern emitted by one first sub-optical unit in the fourth embodiment. Figure 12 is a diagram illustrating the luminous intensity of the first light distribution pattern emitted by one first sub-optical unit in a modified example of the fourth embodiment.

[0014] 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.

[0015] 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.

[0016] (First Embodiment) A vehicle headlight 10 according to the first embodiment will be described with reference to Figures 1 to 6. 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.

[0017] 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 comprises the vehicle headlight 10, a camera 30, a light switch 40, and a vehicle control unit 50.

[0018] The vehicle headlight 10 comprises a lamp control unit 60, a first optical unit 70, a second optical unit 80, and a third optical unit 90. Details of the vehicle headlight 10 will be described later.

[0019] 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.

[0020] The light switch 40 is located near the steering mechanism 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.

[0021] 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.

[0022] 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.).

[0023] 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.

[0024] 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 optical unit 70, the second optical unit 80, and the third optical unit 90 based on surrounding environment information received from the vehicle control unit 50.

[0025] 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. A lamp control unit 60, a first optical unit 70, a second optical unit 80, and a third optical unit 90 are housed in the lamp chamber 13 formed by the lamp body 11 and the outer cover 12.

[0026] The first optical unit 70 is configured to illuminate a region including the cutoff line and at least the region below the cutoff line. Furthermore, the first optical unit 70 illuminates a portion of the illumination region below the cutoff line such that the illumination region illuminated by light reflected from the road surface in front of the vehicle is darker than other portions of the illumination region. Details of the light distribution pattern illuminated by the first optical unit 70 will be described later.

[0027] The first optical unit 70 includes, 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.

[0028] The second optical unit 80 is configured to irradiate light to a region that includes at least a region above the cutoff line. Furthermore, the second optical unit 80 can dim any region within the region above the cutoff line. In this specification, the term "dimming" includes blocking at least a portion of the light emitted from the second optical unit 80 and weakening the intensity of the light emitted from the second optical unit 80. The second optical unit 80 can irradiate, for example, an ADB (Adaptive Driving Beam) light distribution pattern. The ADB light distribution pattern is a high beam light distribution pattern PH that does not irradiate light to regions where objects such as preceding vehicles or oncoming vehicles are present, and is a light distribution pattern that changes the un-irradiated region depending on the presence and location of such objects.

[0029] 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.

[0030] 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.

[0031] Next, with reference to Figure 3, the first light distribution pattern P11 emitted from the first optical unit 70, 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 light distribution pattern P11, 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.

[0032] As illustrated in Figure 3, the first light distribution pattern P11 has a cutoff line CL. The first light distribution pattern P11 is irradiated by the first optical unit 70 onto the area including the cutoff line CL and the area below the cutoff line CL (the area with downward sloping hatching in Figure 3).

[0033] The second light distribution pattern P12, together with the first light distribution pattern P11, forms a so-called high-beam light distribution pattern PH. The second light distribution pattern P12 is irradiated by the second optical unit 80 to a region that includes 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 region 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 light distribution pattern P11 (the portion with vertical hatching in Figure 3). In this embodiment, the third light distribution pattern P13 together with the first light distribution pattern P11 forms 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 low beam light distribution pattern PL, which consists of a first light distribution pattern P11 and a third light distribution pattern P13, by illuminating the first optical unit 70 and the third optical unit 90. That is, in this embodiment, the low beam light distribution pattern PL includes the third light distribution pattern P13, and the third light distribution pattern P13 is illuminated so as to overlap with the right side of the cutoff line CL (the part of the cutoff line CL that is higher in height). Therefore, the area illuminated by the overlapping first light distribution pattern P11 and the third light distribution pattern P13 is brighter than the area illuminated only by the first light distribution pattern P11 and not by the third light distribution pattern P13. In this way, the brightness of the cutoff line of the light distribution pattern PL when the low beam is selected changes in two stages. If we count from the area where no light is illuminated, it can also be said that the brightness of the cutoff line of the light distribution pattern PL when the low beam is selected changes in three stages.

[0037] As illustrated in Figure 5, when the high beams are on, the vehicle headlight 10 illuminates the first optical unit 70 and the second optical unit 80 to emit a high beam light distribution pattern PH consisting of a first light distribution pattern P11 and a second light distribution pattern P12.

[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 light distribution pattern P11 and the region not illuminated by the first light distribution pattern P11, 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 details of road surface reflection and the first light distribution pattern P11. A portion of the light emitted from the vehicle headlight 10 that is directed below the horizontal line (the H-H line in Figure 3) is reflected from the road surface in front of the vehicle, becoming light directed above the horizontal line, which may cause glare to the preceding vehicle 1B. On the virtual vertical screen, a portion of the light emitted from the first optical unit 70 that is directed below the cutoff line CL is reflected from the road surface in front of the vehicle, becoming light directed above the cutoff line CL, which may reach the eye point of the driver of the preceding vehicle 1B.

[0040] The illumination area that contributes to road surface reflection can be determined in advance by simulation or actual measurement before the vehicle headlight 10 is mounted on the vehicle 1. The illumination area that contributes to road surface reflection may also be determined by at least one of the vehicle control unit 50 and the lamp control unit 60 performing real-time image analysis of the imaging data acquired by the camera 30 of the vehicle 1 while the vehicle 1 is in motion.

[0041] The first optical unit 70 illuminates a portion of the illumination area below the cutoff line CL, such that the illumination area illuminated by light reflected from the road surface in front of the vehicle is darker than other portions of the illumination area. In this embodiment, the first optical unit 70 has a plurality of light sources 71, and controls the current value applied to at least one light source to be smaller than the current value applied to another light source.

[0042] Figure 6 is a diagram illustrating the luminous intensity of a portion of the first light distribution pattern P11 in the first embodiment. In this specification, "luminous intensity" refers to the solid angle density of a light beam traveling in a predetermined direction. The first optical unit 70 includes a plurality of light sources 71, namely light source 71A, light source 71B, light source 71C, and light source 71D. Light sources 71A, 71B, 71C, and 71D are arranged at equal intervals in the left-right direction (the width direction of the vehicle 1). The light distribution pattern irradiated from light source 71A is referred to as the first light distribution pattern P11A. The light distribution pattern irradiated from light source 71B, which is to the right of the first light distribution pattern P11A, is referred to as the first light distribution pattern P11B. The light distribution pattern irradiated from light source 71C, which is to the right of the first light distribution pattern P11B, is referred to as the first light distribution pattern P11C. The first light distribution pattern P11D is the light distribution pattern to the right of the first light distribution pattern P11C, which is emitted from the light source 71D. On the virtual screen, the size of the light distribution patterns emitted from each light source 71 is the same. A portion of the right side of the first light distribution pattern P11A overlaps with a portion of the left side of the first light distribution pattern P11B. The same applies to the other first light distribution patterns.

[0043] The lower the current applied to a single light source 71, the lower the luminous intensity of the light distribution pattern irradiated from that light source 71. Figure 6 illustrates a case where the first light distribution pattern P11C is identified as the irradiation area contributing to road surface reflection through simulation or the like. In this case, the current applied to the light source 71C corresponding to the first light distribution pattern P11C is set to be smaller than the current applied to the light source 71B. The current applied to the light source 71C is, for example, 60% of the current applied to the light source 71B. Because the current applied to the light source 71C is relatively small, the luminous intensity of the first light distribution pattern P11C irradiated from the light source 71C is lower than the luminous intensity of the first light distribution pattern P11B irradiated from the light source 71B. As a result, the region RC of the first light distribution pattern P11C that does not overlap with other light distribution patterns becomes dimmer than the region RB of the first light distribution pattern P11B that does not overlap with other light distribution patterns.

[0044] As described above, according to the present embodiment, when the low beam is lit, light is irradiated by the third optical unit 90 so as to overlap the cut-off line CL formed by the first optical unit 70. Therefore, a low beam light distribution pattern PL that is blurred and has good visibility is formed as compared with the cut-off line CL formed only by the first optical unit 70.

[0045] On the other hand, when the high beam is lit, a so-called ADB light distribution pattern is irradiated, and although a distinct cut-off line CL is formed, the cut-off line CL appears only in the dimmed region, so it is difficult to deteriorate visibility.

[0046] Furthermore, the first optical unit 70 irradiates light so that a part of the irradiation region below the cut-off line CL, which is an irradiation region contributing to road surface reflection, becomes darker than other parts of the irradiation region. In the example of FIG. 6, the current value applied to the light source 71C corresponding to the first light distribution pattern P11C as the region contributing to road surface reflection is lower than the current value applied to the light source 71B corresponding to the first light distribution pattern P11B. In this case, the luminous intensity of the first light distribution pattern P11C is lower than that of the first light distribution pattern P11B. Therefore, the region RC of the first light distribution pattern P11C is not irradiated with light as strongly as the region RB of the first light distribution pattern P11B. For this reason, it is possible to make it difficult to give glare to the preceding vehicle 1B due to road surface reflection in the first light distribution pattern P11C.

[0047] Note that the first optical unit 70 may irradiate light to the first light distribution pattern P11B below the cut-off line CL and the first light distribution pattern P11C below the cut-off line CL and darker than the first light distribution pattern P11B, and the third optical unit 90 may irradiate light so as to overlap at least a part of the first light distribution pattern P11C. More specifically, as illustrated in FIG. 6, the third light distribution pattern P13 may be irradiated so as to overlap the upper part of the region RC of the first light distribution pattern P11C. The first light distribution pattern P11B is an example of the first irradiation region. The first light distribution pattern P11C is an example of the second irradiation region.

[0048] According to such a configuration, the first optical unit 70 can darken the first light distribution pattern P11C as the irradiation region that contributes to the road surface reflection, making it difficult to shine the oncoming vehicle 1B due to road surface reflection. Further, when the low beam is lit, the third optical unit 90 irradiates the third light distribution pattern P13 so as to overlap the region RC of the first light distribution pattern P11C, thereby preventing the region RC from becoming too dark.

[0049] (Second Embodiment) Referring to FIG. 7, the first light distribution pattern P111 of the first optical unit 70 according to the second embodiment will be described.

[0050] In the first embodiment, the current value applied to one light source is set to be smaller than the current value applied to another light source. In the second embodiment, the total current value applied to two adjacent light sources is set to be smaller than the total current value applied to two other adjacent light sources.

[0051] FIG. 7 is a diagram illustrating the luminous intensity of a part of the first light distribution pattern P111 in the second embodiment. In the configuration shown in FIG. 7, the same components as those shown in FIG. 6 are denoted by the same reference numerals, and the description thereof is omitted. FIG. 7 illustrates a case where, by simulation or the like, a region RCD where a part on the right side of the first light distribution pattern P11C and a part on the left side of the first light distribution pattern P11D overlap is specified as the irradiation region that contributes to the road surface reflection. In this case, the total current value applied to the adjacent light sources 71C and 71D is set to be smaller than the total current value applied to the adjacent light sources 71A and 71B. The total current value applied to the light sources 71C and 71D is, for example, 60% of the total current value applied to the light sources 71A and 71B.

[0052] Here, the region where a portion of the right side of the first light distribution pattern P11C irradiated from light source 71C overlaps with a portion of the left side of the first light distribution pattern P11D irradiated from light source 71D is defined as region RCD. The region where a portion of the right side of the first light distribution pattern P11A irradiated from light source 71A overlaps with a portion of the left side of the first light distribution pattern P11B irradiated from light source 71B is defined as region RAB. Because the total current applied to light sources 71C and 71D is relatively low, the luminous intensity of region RCD is lower than that of region RAB. As a result, region RCD is dimmer than region RAB.

[0053] Thus, when a region RCD is identified as an illumination area contributing to road surface reflection, the total current applied to light sources 71C and 71D corresponding to the region RCD can be made smaller than the total current applied to light sources 71A and 71B, thereby reducing the glare caused to the preceding vehicle 1B due to road surface reflection in the region RCD.

[0054] (Modified Version of the Second Embodiment) Referring to Figure 8, the first light distribution pattern P211 of the first optical unit 70 according to a modified version of the second embodiment will be described. Figure 8 is a diagram illustrating the luminosity of a part of the first light distribution pattern P211 in a modified version of the second embodiment. In the configuration shown in Figure 8, the same reference numerals are used for components that are the same as those shown in Figure 6, and their descriptions are omitted.

[0055] Figure 8 illustrates a case where, through simulation or other means, a region RBC is identified as the illumination area contributing to road surface reflection, where a portion of the right side of the first light distribution pattern P11B and a portion of the left side of the first light distribution pattern P11C overlap. In this case, the total current applied to adjacent light sources 71B and 71C is set to be smaller than the total current applied to adjacent light sources 71A and 71B. For example, the current applied to light source 71B and the current applied to light source 71C are each 60% of the current applied to light source 71A.

[0056] Here, the region where a portion of the right side of the first light distribution pattern P11B irradiated from light source 71B and a portion of the left side of the first light distribution pattern P11C irradiated from light source 71C overlap is defined as region RBC. Because the current values ​​applied to light sources 71B and 71C are relatively low, the luminous intensity of region RBC is lower than that of region RAB. As a result, region RBC is dimmer than region RAB.

[0057] Thus, when the RBC region is identified as an illumination area that contributes to road surface reflection, by making the total current value applied to light sources 71B and 71C corresponding to the RBC region smaller than the total current value applied to light sources 71A and 71B, it is possible to reduce the glare caused to the preceding vehicle 1B due to road surface reflection in the RBC region.

[0058] (Third Embodiment) Referring to Figure 9, the first light distribution pattern P311 of the first optical unit 70 according to the third embodiment will be described.

[0059] In the first and second embodiments, the multiple light sources 71 were arranged at equal intervals. In the third embodiment, the multiple light sources 71 are arranged such that the distance between two adjacent light sources 71 is greater than the distance between any other two adjacent light sources 71.

[0060] Figure 9 illustrates the luminous intensity of a portion of the first light distribution pattern P311 in the third embodiment. In the configuration shown in Figure 9, components identical to those shown in Figure 6 are denoted by the same reference numerals, and their descriptions are omitted. Figure 9 illustrates a case where, through simulation or other means, a region RCD is identified as the illumination area contributing to road surface reflection, where a portion to the right of the first light distribution pattern P11C and a portion to the left of the first light distribution pattern P11D overlap. In this case, multiple light sources 71 are arranged such that the distance between adjacent light sources 71C and 71D is longer than the distance between adjacent light sources 71A and 71B. For example, the distance between adjacent light sources 71C and 71D is 1.5 times longer than the distance between adjacent light sources 71A and 71B. In this case, as illustrated in Figure 9, region RCD becomes smaller than the light region RAB. As a result of the reduced overlap of the two first light distribution patterns, region RCD becomes darker than region RAB.

[0061] As described above, according to this embodiment, when a region RCD is identified as an illumination area that contributes to road surface reflection, by making the distance between light sources 71C and 71D corresponding to the region RCD longer than the distance between light sources 71A and 71B, it is possible to reduce the glare caused to the preceding vehicle 1B due to road surface reflection in the region RCD.

[0062] (Fourth Embodiment) The first optical unit 470 of the vehicle headlight 10 according to the fourth embodiment will be described with reference to Figures 10 and 11. Figure 10 is a cross-sectional view of the first optical unit 470 according to the fourth embodiment. As illustrated in Figure 10, the first optical unit 470 comprises a single light source 74 and at least one first sub-optical unit 470S having a primary lens 75 and a secondary lens 76. Although one first sub-optical unit 470S is illustrated in Figure 10, the first optical unit 470 may comprise a plurality of first sub-optical units 470S arranged in the left-right direction.

[0063] A single light source 74 may be composed of, for example, an LED (Light Emitting Diode) element or an LD (Laser Diode) element. The light source 74 is configured to emit light toward the primary lens 75.

[0064] The primary lens 75 is configured to direct light emitted from the light source 74 toward the secondary lens 76. The primary lens 75 has a first primary section 751 and a second primary section 752. The first primary section 751 is positioned directly opposite the emission surface of the light source 74. The first primary section 751 is, for example, an aspherical lens with a convex front surface and a flat rear surface. The first primary section 751 is configured to guide light emitted from the light source 74 at a first emission angle θ1 through the secondary lens 76 to a first illumination region R1 below the cutoff line CL. The first emission angle θ1 is the angle between the optical axis AX extending in the front-rear direction through the center of the light source 74 and the upper or lower end of the incident surface of the first primary section 751. Details of the first illumination region R1 will be described later.

[0065] The second primary section 752 is provided to be connected to the first primary section 751. In this embodiment, the second primary section 752 extends upward from the upper part of the first primary section 751. The second primary section 752 has an incident surface 7521 extending rearward from the upper end of the rear surface of the first primary section 751, and a total reflection surface 7522 extending diagonally upward and forward from the rear end of the incident surface 7521. The second primary section 752 takes some of the light emitted from the light source 74 at a second emission angle θ2 which is greater than the first emission angle θ1, and reflects the upward-facing light from the incident surface 7521 and the total reflection surface 7522. Furthermore, the second primary section 752 is configured to guide the reflected light reflected by the total reflection surface 7522 to a third irradiation region R3 which is below the cutoff line CL and separated from the first irradiation region R1, via a secondary lens 76. Details of the third irradiation region R3 will be described later.

[0066] The secondary lens 76 is positioned in front of the primary lens 75. The front surface of the secondary lens 76 is a convex surface that is convex forward, and the rear surface of the secondary lens 76 is a convex surface that is convex backward. The secondary lens 76 is configured to project the light emitted from the first primary section 751 and the second primary section 752 onto the front area of ​​the vehicle 1.

[0067] Next, the first light distribution pattern P411 of the first optical unit 470 according to the fourth embodiment will be described. Figure 11 is a diagram illustrating the luminous intensity of the first light distribution pattern P411S irradiated by one first sub-optical unit 470S in the fourth embodiment. As illustrated in Figure 11, the first sub-optical unit 470S irradiates a first irradiation region R1 and a third irradiation region R3. The first irradiation region R1 is a region below the cutoff line CL and is formed by light irradiated from the first primary unit 751. The first irradiation region R1 is formed by relatively high-intensity light emitted from the light source 74 at a first emission angle θ1. Therefore, the luminous intensity of the first irradiation region R1 irradiated from the first primary unit 751 is relatively high.

[0068] On the other hand, the third irradiation region R3 is a region below the cutoff line CL and is separated below the first irradiation region R1, and is formed by light irradiated from the second primary section 752. The third irradiation region R3 is formed by relatively low-intensity light emitted from the light source 74 at a second emission angle θ2 which is greater than the first emission angle θ1. Therefore, the luminous intensity of the third irradiation region R3 irradiated from the second primary section 752 is relatively low. Furthermore, a region RS that is not irradiated by light is formed between the first irradiation region R1 and the third irradiation region R3.

[0069] If, through simulation or other means, region RS is identified as an illumination area contributing to road surface reflection, according to this embodiment, the primary lens 75 can guide light to the first illumination area R1 and the third illumination area R3, which is separated from the first illumination area R1. Since a region RS that is not illuminated can be formed between the first illumination area R1 and the third illumination area R3, it is possible to reduce the glare caused to the preceding vehicle 1B due to road surface reflection in region RS.

[0070] (Modification of the fourth embodiment) Referring to Figure 12, the first light distribution pattern P411 of the first optical unit 470 according to a modification of the fourth embodiment will be described.

[0071] Except for the configuration of the second primary section 752, the configuration of the first sub-optical unit 470S according to this modified example is the same as that of the first sub-optical unit 470S according to the fourth embodiment. The second primary section 752 of this modified example reflects upward-facing light from a portion of the light emitted from the light source 74 at a large second emission angle θ2 with the total reflection surface 7522. Furthermore, the second primary section 752 is configured to guide the reflected light reflected by the total reflection surface 7522 to a second illumination region R31 via a secondary lens 76, which is below the cutoff line CL and darker than the first illumination region R11. The second illumination region R31 is located below the first illumination region R11. The second illumination region R31 may be separated from the first illumination region R11, or it may overlap with a portion of the lower part of the first illumination region R11.

[0072] Figure 12 illustrates the luminous intensity of the first light distribution pattern P411P irradiated by a single first sub-optical unit 470S in a modified example of the fourth embodiment. In the configuration shown in Figure 12, components identical to those shown in Figure 11 are denoted by the same reference numerals, and their descriptions are omitted. As illustrated in Figure 12, the first sub-optical unit 470S irradiates the first irradiation area R11 and the second irradiation area R31.

[0073] Since the intensity of the light emitted from the light source 74 at the first emission angle θ1 is high, the luminous intensity of the first illumination region R11 is relatively high, and the first illumination region R11 is brightly illuminated. On the other hand, since the intensity of the light emitted from the light source 74 at the second emission angle θ2 is low, the luminous intensity of the second illumination region R31 is relatively low, and the second illumination region R31 is dimmer compared to the first illumination region R11.

[0074] If the second illumination region R31 is identified as an illumination region that contributes to road surface reflection through simulations, according to this modified example, by actively guiding low-intensity light toward the second illumination region R31 with the primary lens 75, it is possible to reduce the glare caused to the preceding vehicle 1B due to road surface reflection in the second illumination region R31.

[0075] (Fifth Embodiment) In the first to third embodiments, the first optical unit 70 had a plurality of light sources 71, and in the fourth embodiment, the first sub-optical unit 470S of the first optical unit 470 had a single light source 74. However, the first optical unit 70 is not limited to these light sources. The first optical unit 70 or the first optical unit 470 may be, for example, a two-dimensional LED array. The first optical unit 70 or the first optical unit 470 may be, for example, a micro-LED array. With such a configuration, the illumination area of ​​the first optical unit 70 or the first optical unit 470 is divided into a plurality of areas in which any area can change its brightness independently of each other. If an illumination area that contributes to road surface reflection is identified by simulation or the like, the current value of the LED corresponding to the identified illumination area can be reduced to reduce glare to the preceding vehicle 1B due to road surface reflection. Alternatively, the vehicle headlight 10 may, in conjunction with the camera 30, identify the illumination area that contributes to road surface reflection in real time and reduce the total current value of the plurality of LEDs corresponding to the identified illumination area.

[0076] The configurations described in each of the following items also constitute part of this disclosure. Item 1: A vehicle headlight comprising: a cutoff line; a first optical unit that irradiates light onto an area including at least a region below the cutoff line; a second optical unit capable of irradiating light onto an area including at least a region above the cutoff line, and capable of dimming any of the areas thereon; and a third optical unit that irradiates light so as to overlap at least a portion of the cutoff line, wherein when the high beam is on, the first optical unit and the second optical unit are illuminated; when the low beam is on, the first optical unit and the third optical unit are illuminated; and the first optical unit irradiates light onto a portion of the illumination area below the cutoff line such that the illumination area where light reflected from the road surface in front of the vehicle is irradiated is darker than other portions of the illumination area. Item 2: The vehicle headlight according to Item 1, wherein the first optical unit has a plurality of light sources, and the current value applied to at least one light source corresponding to the portion of the illumination area is lower than the current value applied to another light source corresponding to the other portion of the illumination area. Item 3: The vehicle headlight according to item 1 or 2, wherein the first optical unit has a plurality of light sources, and the total current applied to two adjacent light sources corresponding to a portion of the illumination area is lower than the total current applied to two other adjacent light sources corresponding to another portion of the illumination area. Item 4: The vehicle headlight according to any one of items 1 to 3, wherein the first optical unit has a plurality of light sources, and the distance between two adjacent light sources is longer than the distance between two other adjacent light sources, and the two adjacent light sources form the portion of the illumination area. Item 5: The vehicle headlight according to any one of items 1 to 4, wherein the first optical unit comprises at least one first sub-optical unit having a single light source, a primary lens, and a secondary lens, the primary lens having a first primary portion that directs light to a first illumination area below the cutoff line, and a second primary portion that directs light to a third illumination area below the cutoff line and spaced apart from the first illumination area.Item 6: The vehicle headlight according to any one of items 1 to 4, wherein the first optical unit comprises a single light source, a primary lens, and at least one first sub-optical unit having a secondary lens, the primary lens having a first primary portion that directs light emitted from the light source at a first emission angle to a first illumination area below the cutoff line, and a second primary portion that directs a portion of light emitted from the light source at a second emission angle greater than the first emission angle to a second illumination area below the cutoff line and darker than the first illumination area. Item 7: The vehicle headlight according to any one of items 1 to 6, wherein the illumination area of ​​the first optical unit is divided into a plurality of areas in which any area can change brightness independently of each other. Item 8: A vehicle headlight according to any one of items 1 to 7, wherein the first optical unit illuminates a first illumination area below the cutoff line and a second illumination area below the cutoff line and darker than the first illumination area, and the third optical unit illuminates light so as to overlap with at least a portion of the second illumination area.

[0077] This application claims priority under Japanese application No. 2024-175923, filed on 7 October 2024, and incorporates all the provisions of the said Japanese application.

Claims

1. A vehicle headlight comprising: a cutoff line; a first optical unit that irradiates light to an area including at least a region below the cutoff line; a second optical unit capable of irradiating light to an area including at least a region above the cutoff line, and capable of dimming any of the areas therein; and a third optical unit that irradiates light so as to overlap at least a portion of the cutoff line, wherein when the high beam is on, the first optical unit and the second optical unit are illuminated; when the low beam is on, the first optical unit and the third optical unit are illuminated; and the first optical unit irradiates light to a portion of the illumination area below the cutoff line such that the illumination area where light reflected from the road surface in front of the vehicle is irradiated is darker than other portions of the illumination area.

2. The vehicle headlight according to claim 1, wherein the first optical unit has a plurality of light sources, and the current value applied to at least one light source is lower than the current value applied to another light source.

3. The vehicle headlight according to claim 1, wherein the first optical unit has a plurality of light sources, and the total current value applied to two adjacent light sources is lower than the total current value applied to two other adjacent light sources.

4. The vehicle headlight according to claim 1, wherein the first optical unit has a plurality of light sources, and the distance between two adjacent light sources is longer than the distance between two other adjacent light sources.

5. The vehicle headlight according to claim 1, wherein the first optical unit comprises a single light source, a primary lens, and at least one first sub-optical unit having a secondary lens, the primary lens having a first primary portion that directs light to a first illumination region below the cutoff line, and a second primary portion that directs light to a third illumination region below the cutoff line and spaced apart from the first illumination region.

6. The vehicle headlight according to claim 1, wherein the first optical unit comprises a single light source, a primary lens, and at least one first sub-optical unit having a secondary lens, the primary lens having a first primary portion that guides light emitted from the light source at a first emission angle to a first illumination region below the cutoff line, and a second primary portion that guides a portion of light emitted from the light source at a second emission angle greater than the first emission angle to a second illumination region below the cutoff line and darker than the first illumination region.

7. The headlight for a vehicle according to claim 1, wherein the illumination area of ​​the first optical unit is divided into a plurality of areas in which the brightness of any area can be changed independently of each other.

8. The vehicle headlight according to any one of claims 1 to 7, wherein the first optical unit irradiates light into a first illumination region below the cutoff line and a second illumination region below the cutoff line and darker than the first illumination region, and the third optical unit irradiates light so as to overlap with at least a portion of the second illumination region.

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