Vehicular lighting fixture

Abstract

To provide a vehicular lighting fixture that can reduce a brightness difference of a cutoff line in a light distribution pattern, appropriately set a brightness difference in a left-right direction in the light distribution pattern, and restrain light distribution unevenness from occurring.SOLUTION: A vehicular lighting fixture comprises: a light source; a projection lens provided on the vehicular front side of the light source; a shade arranged between the light source and the projection lens, and configured to form a cutoff line in a light distribution pattern; and a reflector configured to reflect light from the light source to the side of the projection lens. In the projection lens, a belt-like region 9 extending in the width direction of a vehicle is set in an incidence surface thereof, and a plurality of prisms 23 are provided in a line in the region. The plurality of prisms 23 comprise two kinds or more of prisms 23 having different curvature radii in the length direction of the belt-like region.SELECTED DRAWING: Figure 6

Description

Technical Field

[0001] The present disclosure relates to vehicle lamps.

Background Art

[0002] Generally, a vehicle lamp includes a projection lens provided at the front of a vehicle, a light source provided behind the projection lens, a reflector that reflects light from the light source toward the projection lens side, a shade for forming a cut-off line in a light distribution pattern, and the like. Conventionally, as this type of vehicle lamp, the one described in Patent Document 1 is known.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Patent Document 1 discloses a vehicle lamp provided with a vertical diffusion part for adjusting a cut-off line, which is composed of a projection lens element extending substantially parallel to a horizontal part at the upper edge of a shade, and it is described that the cut-off line is blurred by the vertical diffusion part. However, in this vehicle lamp, although the brightness difference of the cut-off line can be alleviated, in the left-right direction of the cut-off line, the degree of the brightness difference cannot be made different, and the brightness difference cannot be appropriately set for each part. In addition, since the projection lens element is configured to only diffuse light in the vertical direction, there is a problem that light distribution unevenness is likely to occur. In this type of technology, in order to improve the visibility of a driver, it is useful to appropriately set the brightness difference in the left-right direction of an illumination area, and it is also necessary to suppress the occurrence of light distribution unevenness.

[0005] The problem to be solved by the present disclosure is, in a vehicle lamp, to mitigate the brightness difference of the cut-off line in the light distribution pattern, appropriately set the brightness difference in the left-right direction in the light distribution pattern, and further suppress light distribution unevenness.

Means for Solving the Problem

[0006] The vehicle lamp according to the present disclosure includes a light source, a projection lens provided on the vehicle front side of the light source, a shade disposed between the light source and the projection lens and forming a cut-off line in the light distribution pattern, and a reflector that reflects the light from the light source toward the projection lens side. The projection lens has a strip-shaped region extending in the vehicle width direction set on its incident surface, and a plurality of prisms are provided in a row in the region. The plurality of prisms are composed of two or more types of prisms having different radii of curvature in the length direction of the strip-shaped region.

Effect of the Invention

[0007] According to the present disclosure, it is possible to mitigate the brightness difference of the cut-off line in the light distribution pattern, appropriately set the brightness difference in the left-right direction in the light distribution pattern, and further suppress the occurrence of light distribution unevenness.

Brief Description of the Drawings

[0008]

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Mode for Carrying Out the Invention

[0009] Hereinafter, with reference to the accompanying drawings, an embodiment of the present disclosure will be described. Throughout the description of the embodiments described herein, the same elements are denoted by the same numbers. Also, in the embodiments and the drawings, unless otherwise specified, "front" and "rear" indicate the "forward direction" and "backward direction" of the vehicle, respectively, and "up", "down", "left", and "right" indicate the directions as viewed from the driver riding in the vehicle, respectively.

[0010] The vehicle lamp according to the embodiment of the present disclosure is a vehicle lamp mounted on each of the left and right automotive headlights in front of the vehicle. Hereinafter, a vehicle lamp for left-hand driving and arranged on the left side of the vehicle when viewed from the front of the vehicle will be described.

[0011] FIG. 1 is a view of the headlight 1 as seen from the side opposite to its front surface. The headlight 1 shown in this figure includes a low-beam lamp unit 2 and a high-beam lamp unit 3 configured as an AHS (Adaptive High Beam System). This embodiment targets the low-beam lamp unit 2 of the headlight 1. Hereinafter, the low-beam lamp unit will be described as the vehicle lamp 2.

[0012] FIG. 2 is a longitudinal sectional view along the light irradiation optical axis X of the vehicle lamp 2. As shown in FIG. 2, the vehicle lamp 2 includes a light source 4, a reflector 5 arranged so as to cover the light source 4 in a semi-dome shape, a projection lens 6A arranged on the front side of the light source 4, and a shade 7 arranged between the reflector 5 and the projection lens 6A.

[0013] (Light source) The light source 4 can preferably use a semiconductor light source. In this embodiment, an LED, which is a semiconductor light source with a light-emitting chip provided on a substrate formed with power supply electrical wiring (not shown), etc., is used.

[0014] The number of light-emitting chips is not particularly limited, and it may be one or a plurality. Also, the shape of the light-emitting chip is not particularly limited, and it may be a square shape or a rectangular shape. Furthermore, in this embodiment, an example using an LED is shown, but a semiconductor light source such as an LD or an EL (organic EL) may be used instead.

[0015] As shown in FIG. 2, in this embodiment, the substrate is arranged such that the light-emitting surface of the light-emitting chip faces upward, and the light from the light source 4 is irradiated upward.

[0016] (Reflector) The reflector 5 is arranged to cover the light source 4 in a semi-dome shape, and the light from the light source 4 is reflected toward the projection lens 6A by the reflecting surface 8 of the reflector 5. The material used for the reflector 5 can be a metal material with high thermal conductivity (for example, aluminum, etc.) or a resin material, such as polycarbonate, etc.

[0017] The reflecting surface 8 of the reflector 5 is a free-form surface based on a rotational ellipsoid (ellipse). In this embodiment, as shown in FIG. 7, it includes a condensing segment 8A, a diffusing segment 8B, and other segments 8C. Note that FIG. 7 will be described in detail later.

[0018] (Projection lens) In this embodiment, as shown in FIG. 1, as the configuration of the projection lens 6 of the entire headlamp 1, a projection lens 6A for low beam and a projection lens 6B for high beam are integrally formed. When the vehicle is viewed from the side facing the front thereof, the projection lens 6 has a height dimension (width dimension) W1, extends in the vehicle width direction, and has a shape that extends obliquely upward from the center side in the vehicle width direction toward the outside.

[0019] In FIG. 1, the portion surrounded by the dashed-dotted line on the left side is the projection lens 6A for low beam, and the portion surrounded by the dashed-dotted line on the right side is the projection lens 6B for high beam. Details of the projection lens 6A for low beam will be described later. This projection lens 6 can be formed using a transparent resin material such as polycarbonate or acrylic, for example.

[0020] (Shade) The shade 7 can be preferably formed using a light-impermeable material, and as shown in FIG. 2, the upper end of the shade 7 is provided so as to be located near the second focal point of the reflector 5 (condensing segment 8A) and the rear focal point of the projection lens 6A.

[0021] Then, among the light reflected by the reflecting surface 8 of the reflector 5 and traveling toward the projection lens 6A, a part of the light is blocked to form the cut-off lines CL1 and CL2 of the low beam light distribution pattern PL.

[0022] The above is the description of the basic configuration of the vehicle lamp 2. When the light source 4 shown in FIG. 2 is lit in these configurations, the light from the light source 4 is reflected by the reflector 5 and travels toward the projection lens 6 as light that illuminates the front of the vehicle including the center side of the cut-off lines CL1 and CL2 of the light distribution pattern PL shown in FIG. 8, and light that illuminates the front of the vehicle including the outer side in the vehicle width direction of the light distribution pattern PL. In this case, since a part of the light from the reflector 5 is blocked by the shade 7, the cut-off lines CL1 and CL2 are formed in the irradiated light distribution pattern PL.

[0023] (Principal part of the projection lens) Next, the details of the aforementioned projection lens 6A will be described. FIG. 3 is a view showing the back surface of the projection lens 6, where the portion indicated by the one-dot chain line on the right side is the projection lens 6A for the low beam, and the portion surrounded by the one-dot chain line on the left side is the projection lens 6B for the high beam. As shown in this figure, in the projection lens 6A for the low beam, strip-shaped regions 9 extending in the left-right direction are provided in a plurality of rows (five rows in this embodiment) at intervals in the up-down direction on the back surface serving as the incident surface, and a plurality of prisms 23 described later are provided in these regions 9.

[0024] The position where the strip-shaped region 9 is provided within the projection lens 6A, the number of rows of the strip-shaped region 9, etc. are appropriately determined at appropriate positions, the number of rows, etc. according to the configuration, position, etc. of the reflector 5 and the shade 7 arranged behind the projection lens 6A.

[0025] Here, as shown in FIG. 1, the projection lens 6 has the height dimension (width dimension) W1 as described above, extends in the vehicle width direction, and has a shape that extends obliquely upward from the center side in the vehicle width direction toward the outside. However, as shown in FIG. 3, the above strip-shaped region 9 also extends in the vehicle width direction along the upper and lower contour lines of the projection lens 6 and is set to extend obliquely upward of the vehicle, and a plurality of prisms 23 are provided within this region 9.

[0026] The details of the back surface (light incident surface) of the projection lens 6A are shown in FIG. 4. As shown in the figure, the strip-shaped region 9 is set to extend in the left-right direction in the figure, that is, in the vehicle width direction. A plurality of vertical partition lines 22 in the vertical direction (up-down direction) are set at intervals in the direction in which the horizontal partition lines 21 extend with respect to the upper and lower horizontal partition lines 21, 21 that partition this region 9, and prisms 23 are formed within the parallelogram regions surrounded by these horizontal partition lines 21, 21 and vertical partition lines 22, 22.

[0027] As shown in FIG. 5, the prism 23 is formed to be convex or concave with respect to a reference plane 24 when the back surface of the projection lens 6A is taken as the reference plane 24 (FIG. 5 shows the convex case). The reference plane 24 is a convex surface that gently curves with a radius of curvature r1, and the relationship with the radius of curvature r2 of the prism 23 is r1 > r2.

[0028] The prism 23 is formed within a parallelogram region surrounded by the horizontal dividing lines 21, 21 and the vertical dividing line 22 in the strip-shaped region 9 shown in FIG. 4, and is formed to bulge (or dent) from the four horizontal dividing lines 21, 21, 22, 22 toward the central part of the parallelogram. Therefore, this prism 23 diffuses the light incident on the back surface side of the projection lens 6A in the vertical direction and also in the horizontal direction.

[0029] For the sake of convenience of explanation, FIG. 5 shows the case where a plurality of prisms 23 are provided in a state where adjacent prisms 23 are in contact with each other. Regarding the arrangement state of this plurality of prisms 23, not only the case where prisms 23 are provided in all of the adjacent parallelogram regions shown in FIG. 4, but also the case where an appropriate interval is provided between adjacent prisms 23, 23 regardless of the parallelogram region may be included.

[0030] By providing an interval or not between adjacent prisms 23 in this way, and further adjusting the thickness, size, etc. of the prism 23, the degree of light diffusion in the horizontal direction of the light distribution pattern PL can be adjusted, and the degree of light diffusion in the horizontal direction can be appropriately set.

[0031] As shown in FIG. 6, the back surface of the projection lens 6A is partitioned into a condensing area 25 on the right side and a diffusing area 26 on the left side with a vertical dividing line as a boundary. In this case, the condensing area 25 and the diffusing area 26 have a longer horizontal length and a larger area in the condensing area 25 than in the diffusing area 26. The strip-shaped region 9 is formed between these condensing area 25 and diffusing area 26, and the plurality of prisms 23 are formed within this region 9.

[0032] In this embodiment, in the longitudinal direction of the strip-shaped region 9, the prisms 23 in the condensing area 25 and the prisms 23 in the diffusing area 26 among the plurality of prisms 23 are in a relationship where the radius of curvature of the prisms 23 in the condensing area 25 is ≤ the radius of curvature of the prisms 23 in the diffusing area 26. By adopting this configuration, in the left-right direction of the cut-off lines CL1 and CL2 formed in the light distribution pattern PL, the degree of relaxation of the light brightness difference near the center of the cut-off lines CL1 and CL2 becomes larger, and the effect that the outside of the vehicle has a smaller degree of relaxation of the light brightness difference can be obtained.

[0033] The horizontal cross-section of this projection lens 6A in the horizontal direction is shown in FIG. 7. As shown in FIG. 7, the back surface 27 (reference surface 24) has a shape that bulges rearward. The condensing area 25 and the diffusing area 26 are formed within this bulging shape area. The radius of curvature of the condensing area 25 and the radius of curvature of the diffusing area 26 are such that the radius of curvature of the condensing area 25 > the radius of curvature of the diffusing area 26.

[0034] As shown in FIG. 7, the reflector 5 includes a condensing segment 8A, a diffusing segment 8B, and other segments 8C. The condensing segment 8A is configured to reflect the light from the light source 4 toward the condensing area 25 of the projection lens 6. The diffusing segment 8B is configured to reflect the light from the light source 4 toward the diffusing area 26 of the projection lens 6. The other segments 8C are configured to reflect the light from the light source 4 mainly toward the condensing area 25 of the projection lens 6.

[0035] In this configuration, the light reflected by the condensing segment 8A enters the condensing area 25 and then travels forward through the lens and includes the center portion side of the vehicle. The light reflected by the diffusing segment 8B enters the diffusing area 26 and then travels through the lens and in a direction that diffuses toward the outside of the vehicle. The light reflected by the other segments 8C mainly enters the condensing area 25 and then travels through the lens and forward across the entire width direction of the vehicle. In this case, for the condensing segment 8A, the first focal point of its light is near the light source 4, and the second focal point is located between the condensing segment 8A and the projection lens 6. Also, for the diffusing segment 8B, the first focal point of its light is near the light source 4, and the second focal point is located near the front surface of the projection lens 6.

[0036] FIG. 8 is a diagram showing the light distribution pattern irradiated from the projection lens 6. As shown in this figure, since a part of the light from the reflector 5 is blocked by the shade 7 within the light distribution pattern PL, cut-off lines CL1 and CL2 are formed in the irradiated light distribution pattern PL. In the figure, the region indicated by reference numeral 61 is the condensing irradiation region of the light reflected by the condensing segment 8A, 62 is the lateral irradiation region of the light reflected by the diffusing segment 8B, and 63 is the diffusing irradiation region of the light reflected by the other segment 8C.

[0037] FIGS. 9(a) and (b) are diagrams showing a state where the brightness difference of light is alleviated. In these figures, the brightness difference of light is shown roughly. FIG. 9(a) is a diagram when the prism 23 is not provided, and in the regions A1 and A2 at the cut-off lines CL1 and CL2, the brightness difference is distinct. FIG. 9(b) is a diagram when the prism 23 is provided, and it can be seen that the brightness difference in both regions A1 and A2 is alleviated.

[0038] As described above, the vehicle lamp 2 is configured such that a strip-shaped region 9 is set on the back surface of the projection lens 6, and a plurality of concave or convex prisms 23 are provided in the length direction of the region. Therefore, when the light from the light source 4 is incident on and exits from the prism 23, it is diffused in the vertical and horizontal directions. As a result, the brightness difference near the cut-off lines CL1 and CL2 within the light distribution pattern PL can be alleviated, and the occurrence of light distribution unevenness can be suppressed. Therefore, the driver's distant visibility can be improved.

[0039] In addition, since the prism 23 that irradiates light toward the center side of the vehicle is configured such that its radius of curvature is larger than that of the prism 23 that irradiates light outward, the brightness difference near the center of the cut-off lines CL1 and CL2 can be more significantly alleviated, the alleviation of the brightness difference on the outer side of the vehicle can be reduced, and the alleviation of the brightness difference in the left-right direction of the cut-off lines CL1 and CL2 can be appropriately performed.

[0040] In addition, by arranging the plurality of prisms 23 adjacent to each other at intervals in the direction in which the strip-shaped region 9 extends, the degree of alleviating the above-mentioned brightness difference can be appropriately set by appropriately adjusting the interval length, and it is possible to prevent the brightness difference from becoming too strong or the degree of the brightness difference from being too weak.

[0041] In addition, since the strip-shaped region 9 provided with the prism 23 is arranged along the contour line of the projection lens 6 and is configured along the design slant, an appearance with a good look without a sense of disharmony in design can be achieved.

Explanation of Signs

[0042] 1 Headlamp 2 Low-beam lamp unit (vehicle lamp) 3 High-beam lamp unit 4 Light source 5 Reflector 6 Projection lens 6A Projection lens for low beam 6B Projection lens for high beam 7 Shade 8 Reflective surface of reflector 8A Condensing segment 8B Diffusing segment 8C Other segments 9 Strip-shaped region 21 Horizontal dividing line 22 Vertical dividing line 23 Prism 24 Reference plane 25 Condensing area 26 Diffusing area 27 Rear surface 61 Light collection area 62 Side irradiation area 63 Diffuse irradiation area 71 Irradiation area of light of the light collection segment 72 Irradiation area of light of the diffusion segment PL Light distribution pattern CL1 Cut-off line CL2 Cut-off line

Claims

1. A light source, a projection lens provided on the front side of the vehicle of the light source, a shade disposed between the light source and the projection lens and forming a cut-off line in a light distribution pattern, and a reflector that reflects light from the light source toward the projection lens side, wherein the projection lens, a strip-shaped region extending in the vehicle width direction is set on its incident surface, and a plurality of prisms are provided in a row in the region, the plurality of prisms, A vehicle lamp composed of two or more types of prisms having different radii of curvature in the length direction of the strip-shaped region.

2. The projection lens includes a condensing area that irradiates the front of the vehicle with the light condensed by the reflector, and a diffusing area that irradiates the outside of the front of the vehicle with the light diffused by the reflector, the plurality of prisms include condensing prisms provided in the condensing area and diffusing prisms provided in the diffusing area, The vehicle lamp according to claim 1, wherein the radius of curvature of the condensing prism is configured to be equal to or less than the radius of curvature of the diffusing prism.

3. The vehicle lamp according to claim 1 or claim 2, wherein the plurality of prisms have prisms arranged adjacent to each other at intervals in the length direction.

4. The vehicle lamp according to claim 1 or claim 2, wherein a plurality of the strip-shaped regions are provided at intervals in the vertical direction of the projection lens, and a plurality of the prisms are provided in each of the strip-shaped regions.

5. When viewed from the side facing the front surface of the vehicle, the projection lens extends in the vehicle width direction with a height dimension in the vertical direction, and extends obliquely upward from the center side in the vehicle width direction toward the outside, The vehicle lamp according to claim 1 or claim 2, wherein the plurality of prisms are provided in the extending direction of the projection lens.

6. The reflector includes a condensing segment that guides light from the light source to the condensing area of the projection lens, and a diffusing segment that diffuses light from the light source to the diffusing area of the projection lens, The vehicle lamp according to claim 1 or claim 2, further comprising.

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