Vehicle headlight

Abstract

This vehicle headlight is provided with: a plurality of light sources disposed in the left-right direction; a light source-side lens that is disposed in front of the plurality of light sources and that emits light forward; and a projection lens that is disposed in front of the light source-side lens and that illuminates an area in front of the vehicle with light emitted from the light source-side lens. The light source-side lens has an emission surface that emits light. A prism part is provided on a part of the emission surface. The prism part has a curved surface which is convex or concave relative to the emission surface and the ridge line between the curved surface and the emission surface has a curved shape extending around the whole circumference.

Description

Vehicle headlights

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

[0002] 2. Description of the Related Art Vehicle headlamps are known that form an ADB light distribution pattern in front of a vehicle by individually controlling the lighting states of a plurality of light sources such as LEDs.

[0003] JP 2018-98105 A

[0004] In a vehicle headlamp such as that described in Patent Document 1, it is required to appropriately adjust the illuminance distribution in the left-right direction of the ADB light distribution pattern.

[0005] The present invention has been made in view of the above, and has an object to provide a vehicle headlamp that is capable of appropriately adjusting the illuminance distribution in the left-right direction of an ADB light distribution pattern.

[0006] The vehicle headlamp of the present invention comprises a plurality of light sources arranged in the left-right direction, a light source side lens arranged in front of the plurality of light sources and emitting light forward, and a projection lens arranged in front of the light source side lens and emitting the light emitted from the light source side lens toward the front of the vehicle, wherein the light source side lens has an emission surface from which light is emitted, and a prism portion is provided on a part of the emission surface, and the prism portion has a curved surface that is convex or concave with respect to the emission surface, and the ridge line of the connection between the curved surface and the emission surface is curved around the entire circumference.

[0007] According to the present invention, it is possible to appropriately adjust the illuminance distribution in the left-right direction of the ADB light distribution pattern.

[0008] FIG. 1 is a front view showing an example of a vehicle headlamp according to this embodiment. FIG. 2 is a diagram showing a configuration along the A-A cross section in FIG. 1. FIG. 3 is a diagram showing a configuration along the B-B cross section in FIG. 1. FIG. 4 is a front view showing an example of a light source side lens. FIG. 5 is a vertical cross section showing an example of a light source side lens. FIG. 6 is an enlarged view of a portion of the exit surface in FIG. 5 (the portion surrounded by the dashed dotted line). FIG. 7 is a horizontal cross section showing the positional relationship between multiple light sources and the light source side lens. FIG. 8 is a diagram showing an example of the operation of the vehicle headlamp. FIG. 9 is a diagram showing an example of the illuminance distribution of an ADB pattern projected onto a virtual screen in front of a vehicle, using contour lines.

[0009] Hereinafter, an embodiment of a vehicle headlamp according to the present invention will be described with reference to the drawings. However, the present invention is not limited to this embodiment. Furthermore, the components in the following embodiments include those that are easily replaceable by those skilled in the art, or those that are substantially the same.

[0010] In the following description, the front-rear, up-down, left-right directions refer to directions when the vehicle headlamp is mounted on a vehicle and viewed from the driver's seat in the direction of vehicle travel. In this embodiment, the up-down direction is parallel to the vertical direction, and the left-right direction is horizontal. In this embodiment, the front and rear directions refer to directions when the vehicle headlamp is mounted on a vehicle (vehicle-mounted state). For example, when the vehicle headlamp is mounted on the front of the vehicle, the front is the front direction (front side), and the rear is the rear direction (rear side).

[0011] FIG. 1 is a front view showing an example of a vehicle headlamp 100 according to this embodiment. FIG. 2 is a diagram showing the configuration along the A-A cross section in FIG. 1. FIG. 3 is a diagram showing the configuration along the B-B cross section in FIG. 1. Note that in FIG. 3, the outline of some of the configuration is indicated by dashed lines. As shown in FIGS. 1 to 3, the vehicle headlamp 100 includes a plurality of light sources 10, a light source-side lens 20, a projection lens 30, and a support member 40.

[0012] The vehicle headlamp 100 forms an ADB light distribution pattern ahead of the vehicle by individually controlling the on / off of the multiple light sources 10. The vehicle headlamp 100 is disposed on the left and right sides of the front of the vehicle. In this embodiment, a vehicle headlamp 100 disposed on the right side of the vehicle will be described as an example. In this case, the left side of the vehicle headlamp 100 in the left-right direction is the inside of the vehicle, and the right side is the outside of the vehicle. Note that a vehicle headlamp disposed on the left side of the vehicle has a configuration symmetrical to, for example, the vehicle headlamp 100 according to this embodiment.

[0013] The light sources 10 are semiconductor elements such as light-emitting diodes (LEDs). The light sources 10 are arranged side by side in the left-right direction. In this embodiment, for example, 12 light sources 10 are arranged side by side in the left-right direction. The pitch of the light sources 10 in the left-right direction is not particularly limited, and may be the same for all the light sources 10, different for all the light sources 10, or at least two of the light sources 10 may be the same for all the light sources 10.

[0014] One of the multiple light sources 10 is arranged on the optical axis AX of the projection lens 30. The distance between adjacent light sources 10 in the left-right direction may vary depending on the light source 10. Furthermore, the number of light sources 10 arranged on the left side of the optical axis AX is greater than the number of light sources 10 arranged on the right side of the optical axis AX. The multiple light sources 10 have their light-emitting surfaces 11 facing forward of the vehicle. The multiple light sources 10 are mounted on a substrate 12 on which wiring and the like are formed. The substrate 12 is supported by a support member 40.

[0015] The light source-side lens 20 is disposed in front of the plurality of light sources 10. Fig. 4 is a front view showing an example of the light source-side lens 20. Fig. 5 is a longitudinal cross-sectional view showing an example of the light source-side lens 20. Fig. 6 is an enlarged view of a portion (the portion surrounded by the dashed dotted line) of the exit surface 22 in Fig. 5. Fig. 7 is a horizontal cross-sectional view showing the positional relationship between the plurality of light sources 10 and the light source-side lens 20. As shown in Figs. 4 to 7 , the light source-side lens 20 has an entrance surface 21 and an exit surface 22.

[0016] Light from the plurality of light sources 10 is incident on the incident surface 21. The incident surface 21 is curved so that the central portion in the up-down direction protrudes toward the light source 10 in a vertical cross-sectional view (see FIG. 5).

[0017] The incident surface 21 has grooves 24. The grooves 24 are arranged at positions offset in the left-right direction from the optical axis AX of the projection lens 30. In this embodiment, a plurality of grooves 24 are arranged, for example, four grooves 24 on the inside (left) of the vehicle and two grooves 24 on the outside (right) of the vehicle in the left-right direction with respect to the optical axis AX.

[0018] There may be only one groove portion 24. In addition, in the present embodiment, the groove portion 24 is arranged on both the left and right sides of the optical axis AX, but this configuration is not limited to this. For example, the groove portion 24 may be arranged only on one of the left and right sides of the optical axis AX. Also, for example, the groove portion 24 may not be arranged on the outer side of the vehicle (right side) in the left-right direction with respect to the optical axis AX. Also, the groove portion 24 may not be provided.

[0019] Light incident on the incident surface 21 exits from the exit surface 22. A prism portion 25 is provided on a part of the exit surface 22. As shown in Fig. 5, for example, the vertical cross section of the exit surface 22 is a curve that protrudes forward. The prism portion 25 is provided on a part of this curve.

[0020] The prism portion 25 is disposed on the inner side of the vehicle in the left-right direction relative to the optical axis AX of the projection lens 30. The prism portion 25 is also disposed on the lower side in the up-down direction relative to the optical axis AX of the projection lens 30. The prism portion 25 may be disposed on the outer side of the vehicle in the left-right direction relative to the optical axis AX of the projection lens 30, or may be disposed on the upper side in the up-down direction relative to the optical axis AX of the projection lens 30. The prism portion 25 may also be disposed at the same position in at least one of the up-down direction and the left-right direction relative to the optical axis AX of the projection lens 30.

[0021] Prism portion 25 has a curved surface 25a that is convex with respect to light exit surface 22. That is, prism portion 25 has a shape that protrudes forward. As shown in FIG. 6 , in this embodiment, prism portion 25 is provided on a portion of light exit surface 22 that curves downward and rearward. As shown in FIG. 7 , in this embodiment, prism portion 25 is provided on a portion of light exit surface 22 that has a width in the left-right direction in a cross-sectional view. Therefore, prism portion 25 has a shape that protrudes diagonally downward and forward. On the other hand, for example, when prism portion 25 is provided on a portion of light exit surface 22 that curves rearward toward the vehicle interior (left side) (see the dashed line portion in FIG. 7 ), prism portion 25 may have a shape that protrudes diagonally downward and diagonally leftward.

[0022] In this embodiment, the curved surface 25a has a shape based on a spherical surface. The curved surface 25a is smoothly connected to the light exit surface 22. That is, in a cross-sectional view of the prism portion 25 (see, for example, FIG. 6 ), the curved surface 25a and the light exit surface 22 are connected by a straight line or a curve, and no corners are formed. Note that the curved surface 25a of the prism portion 25 may be a curved surface other than a spherical surface. Furthermore, the prism portion 25 may have a curved surface that is concave with respect to the light exit surface 22, that is, a shape that is concave rearward or diagonally upward rearward.

[0023] Prism portion 25 has a closed curved ridgeline around the connection between curved surface 25a and light exit surface 22. In this embodiment, prism portion 25 has a circular ridgeline 25b (shown by a dashed line in the drawing) at the connection between curved surface 25a and light exit surface 22. The shape of ridgeline 25b is not limited to a circular shape, and may be other shapes such as an elliptical shape or an oval shape.

[0024] As shown in FIG. 6 , the curved surface 25a of the prism portion 25 is a spherical surface of radius r that is tangent at a tangent point 25c to a virtual curved surface 22S obtained by translating the exit surface 22 forward by a distance d1. In this embodiment, for example, d1 can be set to 0.3 mm, and r can be set to 1.3 mm. The vertical distance d2 between the optical axis AX of the projection lens 30 and the tangent point 25c can be set to 2.3 mm, for example. The horizontal distance d3 (see FIG. 7 ) between the optical axis AX of the projection lens 30 and the tangent point 25c can be set to 3.8 mm, for example. The curvature of the curved surface 25a changes toward the connecting portion (ridge line 25b) with the exit surface 22 so as to smoothly connect to the exit surface 22.

[0025] The light source side lens 20 is provided with attachment portions 23. The attachment portions 23 are arranged on both left and right sides of the light source side lens 20. The attachment portions 23 are attached via fixing members (not shown), such as screws.

[0026] The projection lens 30 is disposed in front of the light source side lens 20. The projection lens 30 is held by a holding portion or the like (not shown). The projection lens 30 has an incident surface 31 and an exit surface 32. Light from the light source side lens 20 is incident on the incident surface 31. The exit surface 32 emits the light incident from the incident surface 31 forward of the vehicle to form an ADB pattern.

[0027] Next, the operation of the vehicle headlamp 100 configured as described above will be described. Fig. 8 is a diagram showing an example of the operation of the vehicle headlamp 100. When the multiple light sources 10 of the vehicle headlamp 100 are turned on, light is emitted from the light-emitting surface 11. Note that Fig. 8 shows an example of a light ray emitted from one light source 10. Light rays emitted from the other light sources 10 are not shown, but can be similarly illustrated.

[0028] Light rays L emitted from the light source 10 enter the light source-side lens 20 from the incident surface 21. The light rays L incident on the light source-side lens 20 travel toward the exit surface 22. A portion of the light rays L, light rays L2, is emitted forward from the prism portion 25, and the other light rays L1 are emitted forward from the exit surface 22. The emitted light rays L1 and L2 enter the projection lens 30 from the incident surface 31 and exit from the exit surface 32, forming at least a portion of the ADB pattern ahead of the vehicle.

[0029] As shown in Figure 8, the light ray L1 emitted from the light exit surface 22 is emitted with a uniform amount of light in the left-right direction. On the other hand, the light ray L2 emitted from the curved surface 25a of the prism portion 25 crosses in front of the curved surface 25a and is diffused. Similarly, the light rays emitted from each light source 10 cross in front of the curved surface 25a of the prism portion 25 and is diffused. Therefore, the brightness of the portion of the ADB pattern formed in front of the vehicle corresponding to the light ray L2 is lower than that of the other portions. In this way, by forming a portion that is lower in brightness than the other portions, the illuminance distribution of the ADB pattern in the left-right direction can be appropriately adjusted.

[0030] FIG. 9 is a diagram schematically illustrating an example of the illuminance distribution of the ADB pattern P projected onto a virtual screen in front of the vehicle using contour lines. FIG. 9 shows an example in which all light sources 10 are turned on. FIG. 9 also shows a graph showing the change in illuminance of a portion of the ADB pattern P along line C-C above line H-H. In the illuminance graph of FIG. 9, the vertical axis represents illuminance, and the horizontal axis represents horizontal position. In FIG. 9, the illuminance distribution diagram of the ADB pattern P and the illuminance graph are shown corresponding to horizontal positions.

[0031] In the illuminance graph of Fig. 9, the solid line portion I1 indicates the illuminance of the ADB pattern P when the vehicle headlamp 100 of this embodiment has the prism portion 25. The dashed line portion I2 indicates, as a comparative example, the illuminance of the ADB pattern when the vehicle headlamp does not have the prism portion 25. The vehicle headlamp 100 of this embodiment is provided with the prism portion 25. Therefore, as shown in the illuminance distribution diagram and illuminance graph of Fig. 9, it can be seen that the illuminance of the portion of the ADB pattern P on line CC that is irradiated by the light beam emitted from the prism portion 25 (the portion indicated by the horizontal range S) is lower than that of a vehicle headlamp that does not have the prism portion 25.

[0032] As described above, the vehicle headlamp 100 according to this embodiment comprises a plurality of light sources 10 arranged in the left-right direction, a light source side lens 20 arranged in front of the plurality of light sources 10 and emitting light forward, and a projection lens 30 arranged in front of the light source side lens 20 and emitting light emitted from the light source side lens 20 toward the front of the vehicle, the light source side lens 20 having an emission surface 22 from which light is emitted, a prism portion 25 being provided on a part of the emission surface 22, the prism portion 25 having a curved surface 25a that is convex or concave with respect to the emission surface 22, and the ridge line 25b at the connection portion between the curved surface 25a and the emission surface 22 being curved all the way around.

[0033] According to this configuration, the prism portion 25 provided on a part of the exit surface 22 of the light-source-side lens 20 has a curved surface 25a that is convex or concave with respect to the exit surface 22, and the ridge line 25b at the connection portion between the curved surface 25a and the exit surface 22 is curved all the way around, so that the light rays exiting from the curved surface 25a of the prism portion 25 can be diffused relative to other light rays exiting from the exit surface 22. As a result, the brightness of the portion of the ADB pattern formed in front of the vehicle corresponding to the light rays exiting from the curved surface 25a is lower than that of the other portions. By forming such a portion that is lower in brightness than the other portions, the illuminance distribution of the ADB pattern in the left-right direction can be appropriately adjusted.

[0034] In the vehicle headlamp 100 according to this embodiment, the prism portion 25 has a circular ridge 25b at the connection between the curved surface 25a and the light exit surface 22.

[0035] According to this configuration, the ridge line 25b at the connection portion between the curved surface 25a of the prism portion 25 and the light exit surface 22a is circular, so that the curvature of the ridge line 25b is uniform in the circumferential direction, which makes it difficult for streaks to form along the ridge line 25b.

[0036] In the vehicle headlamp 100 according to this embodiment, the prism portion 25 is disposed on the inner side of the vehicle in the left-right direction relative to the optical axis AX of the projection lens 30 .

[0037] According to this configuration, the prism portion 25 is disposed laterally inside the vehicle relative to the optical axis AX of the projection lens 30, so that the brightness of a portion of the ADB pattern outside the vehicle can be reduced compared to other portions.

[0038] In the vehicle headlamp 100 according to this embodiment, the prism portion 25 is disposed below the optical axis AX of the projection lens 30 in the up-down direction.

[0039] With this configuration, the prism portion 25 is positioned vertically below the optical axis AX of the projection lens 30, so that the brightness of a portion of the ADB pattern above the horizontal line can be reduced compared to other portions.

[0040] In the vehicle headlamp 100 according to this embodiment, the prism portion 25 has a curved surface 25a that is basically spherical.

[0041] According to this configuration, the curved surface 25a of the prism portion 25 is made to be a part of a spherical surface, so that the curved surface 25a can be easily formed.

[0042] In the vehicle headlamp 100 according to this embodiment, the emission surface 22 has a vertical cross-sectional shape that is a curve that protrudes forward, and the prism portion 25 is provided on a part of the curve in the vertical cross-sectional view.

[0043] According to this configuration, the prism portion 25 is provided on a part of the curve that is the cross-sectional shape of the exit surface 22 when viewed in vertical section, so that the light rays exiting from the prism portion 25 can be diffused in the vertical direction as well.

[0044] The technical scope of the present invention is not limited to the above-described embodiment, and appropriate modifications can be made without departing from the spirit of the present invention. For example, in the above-described embodiment, the curved surface 25a of the prism portion 25 has a shape based on a spherical surface, but the present invention is not limited to this configuration. The curved surface 25a may be a curved surface other than a spherical surface.

[0045] In the above embodiment, a configuration in which one prism portion 25 is provided on the light-emitting surface 22 has been described as an example, but the present invention is not limited to this configuration. A plurality of prism portions 25 may be provided on the light-emitting surface 22.

[0046] AX...optical axis, L, L1, L2...light ray, 10...light source, 11...light emitting surface, 12...substrate, 20...light source side lens, 21, 31...incident surface, 22, 22a, 32...exit surface, 22S...virtual curved surface, 23...mounting portion, 24...groove portion, 25...prism portion, 25a...curved surface, 25b...ridge line, 25c...contact point, 30...projection lens, 40...support member, 100...vehicle headlamp

Claims

1. A vehicle headlamp comprising: a plurality of light sources arranged in the left-right direction; a light-source-side lens arranged in front of the plurality of light sources and emitting light forward; and a projection lens arranged in front of the light-source-side lens and emitting the light emitted from the light-source-side lens toward the front of the vehicle, wherein the light-source-side lens has an emission surface from which light is emitted, a prism portion is provided on a part of the emission surface, and the prism portion has a curved surface that is convex or concave with respect to the emission surface, and the ridge line of the connection between the curved surface and the emission surface is curved all the way around.

2. The vehicle headlamp according to claim 1, wherein the prism portion has a circular ridge at the connection between the curved surface and the light exit surface.

3. The vehicle headlamp according to claim 1, wherein the prism portion is disposed laterally inward of the optical axis of the projection lens.

4. The vehicle headlamp according to claim 1, wherein the prism portion is disposed vertically below the optical axis of the projection lens.

5. The vehicle headlamp according to claim 1, wherein the curved surface of the prism portion has a shape based on a spherical surface.

6. A vehicle headlamp as claimed in claim 1, wherein the vertical cross section of the light exit surface is a curve that protrudes forward, and the prism portion is provided on part of the curve in the vertical cross section.

Images