JP5228998B2 - Vehicle lighting - Google Patents

Description

  The present invention relates to a vehicular lamp using a light guide plate, and more particularly, to a vehicular lamp using a projection lens including a cylindrical lens portion and a light guide plate in which no illusion light appears (or hardly appears) above a horizontal line. .

  Conventionally, a vehicular lamp using a light guide plate instead of a reflector used in a general projector-type headlamp is known (see, for example, Patent Document 1).

  FIG. 19 is a diagram for explaining the vehicular lamp 200 described in Patent Document 1. In FIG.

  As shown in FIG. 19A, the vehicular lamp 200 described in Patent Document 1 includes a light guide plate 210, a light source 220, and a projection lens 230. A luminance control element (not shown) is formed on the back surface 211 of the light guide plate 210 opposite to the projection lens 230, and an exit surface 212 is formed on the light guide plate 210 side of the projection lens 230. .

  In the vehicular lamp described in Patent Document 1, the light beam from the light source 220 that is incident and guided into the light guide plate 210 and reaches the luminance control element is reflected toward the emission surface 212 by the luminance control element, Through the emission surface 212, a luminance distribution as shown in FIG. 19B is formed over almost the entire area of the emission surface 212. This luminance distribution is inverted and enlarged and projected by the projection lens 230, whereby a predetermined light distribution pattern is formed.

JP 2008-140729 A

  However, in the vehicular lamp 200 described in Patent Document 1, when a projection lens including a cylindrical lens unit is employed as the projection lens 230, the light distribution pattern formed by the vehicular lamp 200 includes, for example, FIG. There is a problem that illusion light P1 (also referred to as glare light) appears above the horizontal line H as shown in FIG.

  In the vehicular lamp 200 described in Patent Document 1, as shown in FIG. 19A, the light guide plate 210 is a flat light guide plate, and the light source 220 faces the end face of the light guide plate 210. Since the light from the light source 220 cannot be collected near the line L corresponding to the horizontal line on the emission surface 212, the current brightness of the LED light source assumed as the light source 220 in Patent Document 1 Now, there is a problem that a luminance distribution including a high luminance portion corresponding to a light distribution pattern including the maximum luminous intensity required for the headlamp cannot be formed.

  Furthermore, Patent Document 1 discloses an example in which the light guide plate 210 is disposed in an inclined state. However, since the light guide plate 210 is a flat light guide plate, the depth dimension of the vehicular lamp 200 is further increased. There is also a problem that it cannot be shortened.

  The present invention has been made in view of such circumstances, and a vehicular lamp using a projection lens including a cylindrical lens portion and a light guide plate in which no illusion light appears (or hardly appears) above the horizon. It is a first problem to provide the above.

  Another object of the present invention is to provide a vehicular lamp using a light guide plate capable of forming a light distribution pattern including the maximum luminous intensity required for a headlamp. Another object of the present invention is to provide a vehicular lamp using a light guide plate that can make the depth dimension of the vehicular lamp shorter than before.

  In order to solve the above-described problem, the invention according to claim 1 is directed to a vehicular lamp including a light guide plate made of a transparent material in a visible light region, a light source, and a projection lens. A light guide plate body bent toward the projection lens in the vicinity of the focal point of the projection lens and a reflection surface with respect to the base end, and the base end includes the incident surface, the first emission surface, and vice versa. The light guide plate main body includes a second emission surface, a second back surface on the opposite side, and a prism surface, and the incident surface is a light beam emitted from the light source. Is a light incident surface for making the light incident on the inside of the light guide plate, the first emission surface and the second emission surface are formed on the projection lens side, and the first back surface and the second back surface are the projections. Formed on the opposite side of the lens, the reflective surface The prism surface is formed between the first back surface and the second back surface or on the first back surface, and the prism surface enters the light guide plate from the incident surface and is guided to reach the prism surface. A light beam from the light source is reflected toward the first and second emission surfaces so that the incident angle with respect to the first and second emission surfaces is within a critical angle, and the first and second emission surfaces are reflected. 2 is a lens cut surface for forming a luminance distribution on the emission surface, and the reflection surface is guided from the incident surface into the light guide plate and reaches the reflection surface. Is reflected toward the vicinity of the focal point of the projection lens so that the incident angles with respect to the first and second emission surfaces are within a critical angle, and the surrounding luminance on the first and second emission surfaces is reflected. A reflective surface for forming a higher brightness portion than the projection surface. The lens is a lens for reversing and enlarging the luminance distribution formed on the first emission surface and the second emission surface to form a predetermined light distribution pattern, and includes at least a cylindrical lens portion. Further, among the light rays from the light source that are arranged between the light guide plate and the projection lens and are irradiated from the light guide plate, the light guide plate directs the light rays toward the lower half of the optical axis of the cylindrical lens portion. It is characterized by comprising a plurality of reflecting surfaces for reflecting toward the surface.

  According to the first aspect of the present invention, the plurality of reflecting surfaces are arranged between the light guide plate unit and the projection lens, so that the light rays irradiated from the first emission surface and the second emission surface and spreading in the left-right direction are Without reaching the lower half of the optical axis of the cylindrical lens portion, the light reaches a plurality of reflection surfaces and is reflected toward the light guide plate by the plurality of reflection surfaces. For this reason, it becomes possible to prevent the light beam spreading in the left-right direction from entering the lower half of the optical axis of the cylindrical lens portion. For this reason, it becomes possible to prevent the dazzling light resulting from the light rays spreading in the left-right direction entering the lower half of the optical axis of the cylindrical lens portion. That is, according to the first aspect of the present invention, it is possible to provide a vehicular lamp that can obtain a light distribution pattern suitable for a headlamp without causing illusion light above the horizontal line.

  According to the first aspect of the present invention, since the plurality of reflecting surfaces are arranged between the light guide plate unit and the projection lens, the light beams reflected toward the light guide plate by the plurality of reflecting surfaces are guided. A part of the light distribution pattern that enters the inside of the optical plate body, is reflected toward the projection lens by the second back surface, etc., and is inverted and magnified by the projection lens is formed. In other words, according to the first aspect of the present invention, it is possible to reuse light rays that spread in the left-right direction.

  According to the first aspect of the present invention, the light guide plate body is bent toward the projection lens in the vicinity of the focal point of the projection lens with respect to the base end portion, and between the first back surface and the second back surface (or The first back surface is formed with a reflecting surface. For this reason, the light from the light source that is incident on the light guide plate from the incident surface and guided and reaches the reflecting surface has an incident angle with respect to the first emitting surface and the second emitting surface within the critical angle by the reflecting surface. In this way, the light is reflected toward the vicinity of the focal point of the projection lens and is emitted from the first emission surface and the second emission surface. Thereby, the luminance distribution including the high luminance part higher than the surrounding luminance on the first emission surface and the second emission surface (the luminance including the high luminance part corresponding to the light distribution pattern including the maximum luminous intensity required for the headlamp). Distribution) is formed. The luminance distribution including the high luminance part is inverted and enlarged and projected by the projection lens. Thereby, it is possible to form a light distribution pattern including the maximum luminous intensity required for the headlamp.

  According to the first aspect of the present invention, the light guide plate body is bent toward the projection lens near the focal point of the projection lens with respect to the base end. For this reason, it is possible to shorten the dimension of the light guide plate body in the optical axis direction. For this reason, it becomes possible to make the depth dimension of a vehicle lamp shorter than before.

  According to a second aspect of the present invention, in the first aspect of the invention, each of the plurality of reflecting surfaces emits a light beam that travels toward the lower half of the optical axis of the cylindrical lens portion that has reached the reflecting surface. It is arranged in an inclined posture so as to be reflected toward the light guide plate immediately above the reflecting surface.

  According to the second aspect of the present invention, each of the plurality of reflecting surfaces directs the light beam that reaches the reflecting surface toward the lower half of the optical axis of the cylindrical lens portion toward the light guide plate immediately above the reflecting surface. It is arranged in an inclined posture so as to be reflected. For this reason, it is possible to efficiently (without waste) incident light beams directed toward the lower half of the optical axis of the cylindrical lens portion to the light guide plates directly above by the plurality of reflection surfaces.

  ADVANTAGE OF THE INVENTION According to this invention, it becomes possible to provide the vehicle lamp using the projection lens containing a cylindrical lens part and a light-guide plate in which a dazzling light does not appear above a horizontal line (or hardly appears).

(A) is a top view of a vehicular lamp that is an embodiment of the present invention, (b) is a front view of the vehicular lamp that is an embodiment of the present invention, and (c) is an embodiment of the present invention. It is a side view of a vehicle lamp. (A) is a top view of a light guide plate unit used in a vehicular lamp that is an embodiment of the present invention, (b) is a front view of a light guide plate unit used in a vehicular lamp that is an embodiment of the present invention, (C) is a side view of the light-guide plate unit used for the vehicle lamp which is embodiment of this invention. It is a side view of the vehicular lamp which is an embodiment of the present invention. It is sectional drawing for demonstrating the light-guide plate main body 11b (prism surface 11b3). It is a graph showing the directivity characteristic (up-down direction) for every prism angle (alpha) of the light beam irradiated from the 2nd output surface 11b1 of the light-guide plate main body 11b. This is an example in which the light guide plate body 11b is arranged in a posture inclined about 45 ° toward the projection lens 20 in the vicinity of the focal point F3 of the projection lens 20 with respect to the base end portion 11a. It is sectional drawing for demonstrating the reflective surface 11c (ellipsoidal reflective surface). It is a figure for demonstrating the virtual image F0 of the light source 12. FIG. It is a figure for demonstrating the motion of the horizontal direction of the light ray from each light source 12 light-guided by the light-guide plate main body 11b. It is the graph which plotted the luminous flux divergence curve (simulation value) of the vertical cross section of the 1st and 2nd output surfaces 11a2 and 11b1, and the measurement light intensity distribution (measurement value) of the conventional general projector type headlamp. It is an example of the light distribution pattern formed with the vehicle lamp 100 (without a main shade and a some reflective surface) of embodiment. It is a graph for demonstrating the angle distribution of the light ray which enters into the lower half of the cylindrical lens part 21a. It is a side view of the vehicle lamp 100 using the some reflective surfaces 30a-30e of embodiment. It is a perspective view of vehicular lamp 100 using a plurality of reflective surfaces 30a-30e of an embodiment. (A) is a top view of the vehicular lamp 100 using the plurality of reflecting surfaces 30a to 30e of the embodiment, and (b) is a front view of the vehicular lamp 100 using the plurality of reflecting surfaces 30a to 30e of the embodiment. FIG. 4C is a side view of the vehicular lamp 100 using the plurality of reflecting surfaces 30a to 30e of the embodiment, and FIG. 4D is a vehicular lamp 100 using the plurality of reflecting surfaces 30a to 30e of the embodiment. FIG. It is a figure for demonstrating the focal line FL. It is an example of the light distribution pattern formed with the vehicle lamp 100 using the some reflective surfaces 30a-30e of embodiment. It is a modification of the vehicle lamp 100 using the some reflective surfaces 30a-30e of embodiment. It is a figure for demonstrating the vehicle lamp using the conventional light-guide plate.

  Hereinafter, a vehicular lamp that is an embodiment of the present invention will be described with reference to the drawings.

  1A is a top view of a vehicular lamp that is an embodiment of the present invention, FIG. 1B is a front view of the vehicular lamp that is an embodiment of the present invention, and FIG. It is a side view of the vehicular lamp which is an embodiment of the invention. FIG. 2A is a top view of a light guide plate unit used in a vehicle lamp that is an embodiment of the present invention, and FIG. 1B is a light guide plate unit used in a vehicle lamp that is an embodiment of the present invention. FIG. 1C is a side view of a light guide plate unit used in a vehicular lamp that is an embodiment of the present invention. FIG. 3 is a side view of a vehicular lamp that is an embodiment of the present invention.

  The vehicular lamp 100 according to this embodiment is applied to a headlamp and a fog lamp, and includes a light guide plate unit 10 and a projection lens 20 as shown in FIGS. In the vehicular lamp 100 of the present embodiment, the luminance distribution (light flux divergence distribution) formed on the projection lens 20 side surface (first and second emission surfaces 11a2 and 11b1) of the light guide plate unit 10 (light guide plate 11). ) Is inverted and enlarged and projected by the projection lens 20, so that a predetermined light distribution pattern is formed. Hereinafter, an example in which the vehicular lamp 100 of the present embodiment is applied to a so-called projector-type headlamp will be specifically described.

  First, the light guide plate unit 10 will be described.

  As shown in FIGS. 2 and 3, the light guide plate unit 10 includes a light guide plate 11, a plurality of light sources 12, reflection sheets 13 and 14, and the like.

  As shown in FIG. 3, the light guide plate 11 includes a base end portion 11a, a light guide plate body 11b bent toward the projection lens 20 in the vicinity of the focal point F3 of the projection lens 20, and a reflection surface 11c. It is integrally formed by injection molding a transparent material (transparent or translucent resin such as acrylic or polycarbonate) in the visible light region. Thus, since the light guide plate body 11b is bent toward the projection lens 20 in the vicinity of the focal point F3 of the projection lens 20 with respect to the base end portion 11a, the size of the light guide plate body in the optical axis direction can be shortened. It becomes possible. For this reason, the depth dimension of the vehicular lamp 100 can be made shorter than before.

  The base end portion 11a includes an incident surface 11a1, a first exit surface 11a2, a first back surface 11a3 on the opposite side, and the like.

  The incident surface 11a1 is a light incident surface for causing the light irradiated from the light source 12 (also referred to as a light beam or a light beam) to enter the light guide plate 11. For example, the cross-sectional shape 11a1 illustrated in FIG. It is formed in the lower end of the base end part 11a as a horizontal surface extended in the direction orthogonal to the paper surface (left and right direction in FIG. 2A).

  The first emission surface 11a2 is, for example, a projection of the base end portion 11a as a vertical surface in which the cross-sectional shape 11a2 shown in FIG. 3 extends in the longitudinal direction (the direction perpendicular to the paper surface in FIG. 3; the left-right direction in FIG. 2A). It is formed on the lens 20 side. The first back surface 11a3 is, for example, a projection lens of the base end portion 11a as a vertical surface in which the cross-sectional shape 11a3 shown in FIG. 3 extends in the longitudinal direction (a direction perpendicular to the paper surface in FIG. 3; the left-right direction in FIG. 2A). 20 is formed on the opposite side. As shown in FIGS. 2 and 3, a part of the first emission surface 11 a 2 is covered with the front-side reflection sheet 13, and the first back surface 11 a 3 is covered with the back-side reflection sheet 14.

  2, 3, and 9, a plurality of light sources 12 (indicated by 12 a to 12 d in FIG. 9) face the optical axis upward, and the light emitting surface 12 a faces the light guide plate 11. It arrange | positions along the longitudinal direction in the state contacted to the entrance plane 11a1, and is fixed to the entrance plane 11a1 with a transparent resin or the like, for example.

  The light source 12 is, for example, an LED light source (or a cold cathode fluorescent lamp (CCFL)) such as an LED package in which one (or plural) LED chips of white (or RGB three colors) are packaged.

  In the present embodiment, in order to obtain the maximum luminous intensity, as shown in FIG. 9, the vertical section including the one rotation axis AX (optical axis) and the other rotation axis AX (optical axis) of the projection lens 20. On the top, light sources 12a and 12b are arranged, respectively. Further, in order to form a diffused light distribution pattern, light sources 12c and 12d are arranged at positions shifted inward from one rotation axis AX and the other rotation axis AX.

  As shown in FIG. 3, the light guide plate body 11b is a flat light guide plate including a second emission surface 11b1, a second back surface 11b2 on the opposite side, a plurality of prism surfaces 11b3 (sawtooth-shaped prism array), and the like. The base end portion 11a is disposed in a posture inclined toward the projection lens 20 in the vicinity of the focal point F3 of the projection lens 20. In order to emit all the light rays incident on the light guide plate main body 11b, the cross-sectional shape of the light guide plate main body 11b becomes tapered as approaching the tip as shown in FIG.

  The second emission surface 11b1 is a projection lens 20 of the light guide plate body 11b as an inclined surface in which the cross-sectional shape 11b1 shown in FIG. 3 extends in the longitudinal direction (a direction perpendicular to the paper surface in FIG. 3; the left-right direction in FIG. 2A). Formed on the side. The second back surface 11b2 has a cross-sectional shape 11b2 shown in FIG. 3 as an inclined surface extending in the longitudinal direction (a direction orthogonal to the paper surface in FIG. 3; the left-right direction in FIG. 2A) and the projection lens 20 of the light guide plate body 11b. Is formed on the opposite side.

  As shown in FIG. 4, the plurality of prism surfaces 11b3 are guided by being incident on the light guide plate 11 from the incident surface 11a1, and the light beams from the light source 12 reaching the plurality of prism surfaces 11b3 are converted into the first and first light beams. The light is reflected toward the first and second emission surfaces 11a2 and 11b1 so that the incident angle with respect to the two emission surfaces 11a2 and 11b1 is within the critical angle, and a luminance distribution is formed on the first and second emission surfaces 11a2 and 11b1. It is a lens cut surface for forming. The plurality of prism surfaces 11b3 is, for example, a second lens cut surface having a planar shape in which the cross-sectional shape 11b3 shown in FIG. 4 extends in the longitudinal direction (a direction orthogonal to the paper surface in FIG. 4; the left-right direction in FIG. 2A). The back surface 11b2 is formed in parallel in the vertical direction.

  Next, the operation of the prism surface 11b3 will be described.

  As shown in FIG. 4, the light beam from each light source 12 guided to the light guide plate body 11b repeats total reflection on each prism surface 11b3 and the second emission surface 11b1. The incident angle of this light ray with respect to the second exit surface 11b1 becomes smaller every time it is totally reflected by each prism surface 11b3. For this reason, the light beam from each light source 12 guided to the light guide plate body 11b eventually reaches the critical angle, and is emitted from the first and second emission surfaces 11a2 and 11b1 at that time. As a result, a luminance distribution (light flux divergence distribution) is formed over substantially the entire area of the first and second emission surfaces 11a2 and 11b1.

  The amount of light emitted from the first and second emission surfaces 11a2 and 11b1 increases as the prism angle α (vertical angle; see FIG. 4) of the prism surface 11b3 increases. FIG. 5 illustrates this. Therefore, by adjusting the prism angle α of the prism surface 11b3, it is possible to form a luminance distribution (light flux divergence distribution) suitable for the headlamp over almost the entire area of the first and second emission surfaces 11a2 and 11b1. Become. For example, it is possible to form a luminance distribution that naturally changes from high luminance to low luminance by gradually changing the prism angle α as the distance from the reflecting surface 11c increases. Further, by adjusting the prism angle α of the prism surface 11b3, a luminance distribution (light flux divergence distribution) suitable for, for example, a fog lamp other than the headlamp is formed over almost the entire area of the first and second emission surfaces 11a2 and 11b1. Is also possible.

  Next, the technical significance of inclining the light guide plate body 11b with respect to the base end portion 11a will be described.

  FIG. 5 is a graph showing the directivity (vertical direction) for each prism angle α of the light beam emitted from the second exit surface 11b1 of the light guide plate body 11b. The prism angle α (= small, small, medium, slightly large). , Large, and very large).

  In the present embodiment, in order to maximize the amount of light incident on the projection lens 20, the prism 11d having a prism angle α = “slightly large” as compared with other prism angles is employed, and FIG. As shown in FIG. 6, the light guide plate main body 11 b is disposed in a posture inclined about 45 ° toward the projection lens 20 near the focal point F <b> 3 of the projection lens 20 with respect to the base end portion 11 a.

  Next, the technical significance of the reflecting surface 11c will be described.

  The reflection surface 11c is formed between the second back surface 11b2 and the first back surface 11a3 as shown in FIG.

  As shown in FIG. 7, the reflection surface 11c is incident on the light guide plate 11 from the incident surface 11a1 and is guided, and the light from the light source 12 reaching the reflection surface 11c is converted into the first and second emission surfaces 11a2. , 11b1 is reflected toward the vicinity of the focal point F3 of the projection lens 20 so that the incident angle is within the critical angle, and high brightness portions higher than the surrounding brightness are formed on the first and second emission surfaces 11a2 and 11b1. It is a reflective surface for. The reflecting surface 11c is formed in a predetermined range including the optical axis of the light source 12, for example, in order to obtain max luminous intensity. In the reflecting surface 11c, for example, the first focal point F1 is set near the light source 12 (for example, near the center of the virtual image F0 of the light source 12 shown in FIG. 8), and the second focal point F2 is set near the focal point F3 of the projection lens 20. It is formed as an elliptical reflecting surface (see FIGS. 3 and 7).

  As shown in FIG. 8, the light beam emitted from the light source 12 (light emitting surface 12a) is refracted inward by the incident surface 11a1. This refracted light beam can be regarded as being irradiated from the virtual image F0 shown in FIG. The first focus F1 is set near the center of the virtual image F0 of the light source 12. Thus, by setting the first focus F1 in the vicinity of the center of the virtual image F0, the light condensing property to the second focus F2 is improved, and the emission surface near F2 has higher luminance, so that a high maximum luminous intensity is obtained. Thus, a light distribution pattern suitable for a headlamp can be formed. Note that the position, size, and focus of the virtual image F0 are determined by the shape of the incident surface 11a1, the size of the second exit surface 11b1, and the like. When the light emitting surface 12a is a flat surface, the image is relatively blurred.

  As shown in FIG. 7, the light beam from the light source 12 that is incident on the light guide plate 11 and guided and reaches the reflection surface 11c is directed toward the first and second emission surfaces 11a2 and 11b1 by the reflection surface 11c. The light is reflected, passes through the first and second emission surfaces 11a2 and 11b1, and is condensed near the focal point F3 (second focal point F2) of the projection lens 20. As a result, high brightness portions higher than the surrounding brightness are formed on the first and second emission surfaces 11a2 and 11b1.

  For example, as shown in FIGS. 3 and 7, when the second focal point F2 is set slightly above the focal point F3 of the projection lens 20 (for example, a position 1 mm above), the first and second emission surfaces 11a2 are used. , 11b1 is formed at a portion about 1 ° above the line L corresponding to the horizontal line, which is higher in luminance than the surrounding luminance (see FIG. 10). The luminance distribution (light flux divergence distribution) including this high luminance portion is inverted and enlarged and projected by the projection lens 20. As a result, a light distribution pattern suitable for a low beam whose luminous intensity is lower in the lower part than the horizontal line (for example, in a range corresponding to about 1 ° on the lower side) than the surrounding luminous intensity is formed.

  Further, for example, when the second focal point F2 is set to the focal point F3 of the projection lens 20, the portion corresponding to the intersection of the horizontal line and the vertical line of the first and second emission surfaces 11a2 and 11b1 is more than the surrounding luminance. A high high-luminance part is formed. The luminance distribution (light flux divergence distribution) including this high luminance portion is inverted and enlarged and projected by the projection lens 20. Thereby, a light distribution pattern suitable for a traveling beam in which the light intensity in the vicinity of the intersection of the horizontal line and the vertical line is higher than the surrounding light intensity is formed. In addition, when forming the light distribution pattern suitable for a traveling beam, it is preferable to omit the front side reflection sheet 13.

  The front-side reflection sheet 13 is a reflection sheet for reflecting the light beam from the light source 12 that has been transmitted to the outside from the first emission surface 11a2 and entering the light guide plate 11 again. As shown in FIGS. The lower side is covered rather than the line L corresponding to the horizontal line of 1 emission surface 11a2. The back-side reflection sheet 14 is a reflection sheet for reflecting the light beam from the light source 12 that has been transmitted to the outside from the first back surface 11a3 and the second back surface 11b2 and again entering the light guide plate body 11b. 2 The back surface 11b2 is covered. For this reason, since the light rays from the light source 12 transmitted to the outside from the first back surface 11a3 and the second back surface 11b2 are returned to the inside of the light guide plate 11 by the reflection sheets 13 and 14, the light use efficiency can be improved. It becomes possible. Each of the reflection sheets 13 and 14 is, for example, a high reflectance sheet such as a metal deposition sheet such as silver or aluminum, or a foamed resin sheet. In addition, it is preferable to arrange | position each reflection sheet 13 and 14 in parallel with respect to each surface 11a3.

  As shown in FIGS. 2 and 3, the front-side reflection sheet 13 is a shade that shields a part of light rays emitted from the first and second emission surfaces 11 b 1 and 11 a 2 toward the projection lens 20 and forms a cut-off line. It also serves as a role. In order to give the front-side reflection sheet 13 the role of a shade, the upper edge 13a of the front-side reflection sheet 13 extends in the horizontal direction along the line L corresponding to the horizontal line, as shown in FIG. A Z-shaped step portion is formed in the vicinity of the focal point F3 of the projection lens 20. Thus, since the 1st output surface 11a2 is covered with the front side reflection sheet 13 which has the upper end edge 13a extended along the line L corresponding to a horizontal line, the light distribution which has a clear cut-off line suitable for a passing beam A pattern can be formed.

  As shown in FIG. 1 and the like, in the projection lens 20 having two rotation axes (optical axes), in the case of left-hand traffic, only the portion corresponding to the left rotation axis AX (optical axis) when viewed from the front of the vehicle is Z. What is necessary is just to form in the level | step-difference part of a type | mold (refer FIG.2 (b)). In this way, since the light beam irradiated from the vicinity of the line L corresponding to the horizontal line on the light guide plate 11 shown in FIG. 2B does not enter the projection lens 20, the light beam is irradiated upward from the horizontal line of the opposite lane. It is possible to prevent this.

  Next, the projection lens 20 will be described.

  The projection lens 20 is a lens for inverting and enlarging the luminance distribution formed on the first and second emission surfaces 11a2 and 11b1 to form a predetermined light distribution pattern. For example, as shown in FIG. 1 is a solid lens body extending in the longitudinal direction (left-right direction in FIG. 1A) including the exit surface 21 and the entrance surface 22 on the opposite side. The projection lens 20 is integrally formed by injection molding of a resin transparent in the visible light region (for example, a transparent or translucent material such as acrylic or polycarbonate) or glass.

  The exit surface 21 is a lens surface including a cylindrical lens surface 21a, a right lens surface 21b, and a left lens surface 21c, and the entrance surface 22 is formed as a flat surface. Hereinafter, the lens portion between the cylindrical lens surface 21a and the incident surface 22 on the opposite side may be referred to as a cylindrical lens portion 21a. In addition, the lens portion between the right lens surface 21b (left lens surface 21c) and the incident surface 22 on the opposite side may be referred to as the right lens portion 21b (left lens portion 21c).

The cylindrical lens surface 21a is a cylindrical lens surface extending in the longitudinal direction (left-right direction in FIG. 1A), and a right lens surface 21b and a left lens surface 21c are formed on both left and right ends, respectively. The lens surface 21c is a hemispherical aspherical lens surface cut along a plane including the optical axis, and is formed as a lens surface in which the respective cut surfaces are flush with each other at the left and right ends of the cylindrical lens surface 21a. ing.

  According to the vehicular lamp 100 having the above-described configuration, as shown in FIGS. 4 and 7, the light beams from the respective light sources 12 incident from the base end portion 11 a are allowed to travel along the run-up section of the base end portion 11 a (the first emission surface 11 a 2 and the first output surface). The luminance unevenness is reduced by passing through the base end portion 11a) between the 1 back surface 11a3, and then guided to the light guide plate body 11b (or reaches the reflection surface 11c).

  As shown in FIG. 4, the light from each light source 12 guided to the light guide plate body 11b repeats total reflection at each prism 11d and the second exit surface 11b1. The incident angle of this light ray with respect to the second exit surface 11b1 becomes smaller every time it is totally reflected by each prism surface 11b3. For this reason, the light beam from each light source 12 introduced into the light guide plate body 11b eventually reaches the critical angle, and is emitted from the first and second emission surfaces 11a2 and 11b1 at that time. As a result, a luminance distribution (light flux divergence distribution) is formed over substantially the entire area of the first and second emission surfaces 11a2 and 11b1.

  On the other hand, as shown in FIG. 7, the light beam from each light source 12 that has reached the reflecting surface 11c is reflected by the reflecting surface 11c toward the first and second emitting surfaces 11a2 and 11b1, and the first and second light beams are reflected. The light passes through the emission surfaces 11a2 and 11b1, and is condensed near the focal point F3 (second focal point F2) of the projection lens 20. Thereby, the brightness | luminance part higher than the surrounding brightness | luminance is formed in 1st and 2nd output surface 11a2, 11b1.

  As described above, a luminance distribution (light flux divergence distribution) including a high luminance portion is formed on the first and second emission surfaces 11a2 and 11b1.

  In addition, as shown in FIG. 4, the light rays transmitted to the outside from the first emission surface 11a2 of the base end portion 11a and the second back surface 11b2 of the first back surface 11a3 and the light guide plate body 11b are reflected on the back side reflection sheet 14 (front side). Since the light is again returned to the inside of the light guide plate 11 by the reflection sheet 13) and emitted from the first and second emission surfaces 11a2 and 11b1, it is possible to improve the light utilization efficiency.

  Next, the horizontal movement of the light beam from each light source 12 guided to the light guide plate body 11b will be described. FIG. 9 is a diagram for explaining the horizontal movement of the light beam from each light source 12 guided to the light guide plate body 11b.

  As shown in FIG. 9, the light from each light source 12 that is guided and guided into the light guide plate 11 is partially shielded by the front-side reflection sheet 13, then passes through the projection lens 20, and the left and right lens surfaces 21b. , 21c is irradiated as condensed light condensed on the rotation axis AX side, and the light transmitted through the cylindrical lens portion 21a is irradiated as diffused light diffused in the left-right direction.

  For this reason, the light distribution pattern formed by reversing and enlarging the luminance distribution of the first and second emission surfaces 11a2 and 11b1 by the projection lens 20 is wide in the left-right direction having a clear cut-off line, and Thus, a light distribution pattern suitable for a headlamp in which the luminous intensity in the vicinity of the horizon is higher than the luminous intensity in the surroundings is obtained. Since the diffusion angle is substantially the same as the incident angle to the cylindrical lens portion, it is possible to obtain a light distribution that diffuses in the left-right direction by making the cylindrical lens portion longer in the longitudinal direction.

  The inventors of the present application performed a simulation using a predetermined program. As a result, in the vertical direction, as shown in FIG. 10, it was confirmed that the light distribution pattern formed by the vehicular lamp 100 having the above configuration is a light distribution pattern suitable for the headlamp. FIG. 10 is a graph plotting luminous flux divergence curves (simulated values) of vertical sections of the first and second exit surfaces 11a2 and 11b1, and measured light intensity distributions (measured values) of a conventional general projector type headlamp. It is.

  Referring to FIG. 10, the luminous flux divergence curves (simulation values) of the vertical sections of the first and second emission surfaces 11a2 and 11b1 are substantially the same as the actual luminous intensity distribution (measured values) of a conventional general projector type headlamp. That is, it can be confirmed that the light distribution pattern formed by the vehicular lamp 100 of the present embodiment is a light distribution pattern suitable for a headlamp in the vertical direction.

  On the other hand, the inventors of the present application performed a simulation using a predetermined program and observed a light distribution pattern (see FIG. 11) formed by the vehicular lamp 100 having the above configuration. As a result, in the horizontal direction, it has been found that the light distribution pattern includes the illusion light P1 (also referred to as glare light) above the horizontal line H. FIG. 11A is an example of a light distribution pattern formed by the vehicular lamp 100 of this embodiment, and FIG. 11B is from the optical axis AX of the cylindrical lens portion 21a of the vehicular lamp 100 of this embodiment. Is a light distribution pattern in which only the light emitted from the lower half is extracted, and shows that the illusion light P1 appears above the horizontal line H in the vicinity of 35 degrees on both the left and right sides. From these figures, it became clear that the light from which the source of the illusion light P1 is incident on the lower half of the optical axis AX of the cylindrical lens portion 21a generates the illusion light P1.

  The inventors of the present application diligently studied the cause of the appearance of the illusion light P1. As a result, first, since the prism surface 11b3 has a linear shape extending in the left-right direction (see FIG. 4 and the like), the light rays from the light sources 12a to 12b (also referred to as point light sources) are transmitted inside the light guide plate body 11b. Even after being irradiated from the light guide plate main body 11b (first and second emission surfaces 11a2 and 11b1), the light sources 12a to 12d spread radially (see FIG. 9). Of light beams spreading in the right and left direction (hereinafter simply referred to as light beams spreading in the left and right direction) are incident on the lower half of the optical axis AX of the cylindrical lens portion 21a (the region indicated by the oblique lines in FIG. 1). Third, the light beam spreading in the left-right direction is incident on the lower half of the optical axis AX of the cylindrical lens portion 21a, so that the light beam from the cylindrical lens portion 21a. Is irradiated obliquely upward, found glare P1 appears that above the horizontal line H.

  Then, as a result of further investigation based on the above knowledge, the inventors of the present application, as a result, emit light beams (including light beams spreading in the left-right direction) toward the lower half of the optical axis AX of the cylindrical lens portion 21a. If a reflecting surface is disposed between the light guide plate unit 10 and the projection lens 20 so as to reflect toward the light beam 11b (second emitting surface 11b1), first, the light beam spreading in the left-right direction is reflected on the reflecting surface. Since the light is shielded and can be prevented from entering the lower half of the optical axis AX of the cylindrical lens portion 21a, the light beam spreading in the left-right direction enters the lower half of the optical axis AX of the cylindrical lens portion 21a. It is possible to prevent the resulting illusion light P1, and secondly, light rays (including light rays spreading in the left-right direction) toward the lower half of the optical axis AX of the cylindrical lens portion 21a. There because that would be incident on to light guide plate main body 11b reflected by the reflective surface, it is possible to reuse the light spreading in the lateral direction, inspired with.

  However, the inventors of the present application measured the angular distribution of light rays incident on the lower half of the optical axis AX of the cylindrical lens portion 21a. As a result, first, the angular distribution of the light rays is shown in FIG. Thus, each range (Z0-5, Z5-10, Z10-Z15, Z15-20, Z20 ~) on the optical axis AX (Z axis with the base point Z0 and the tip Z35 indicated by the arrow A in FIG. 13) 25) different from each other, and secondly, due to this, the light guide plate transmits light incident on the lower half of the optical axis AX of the cylindrical lens portion 21a only by using a single reflecting surface. It has been found that it is not possible to enter the main body 11b (second emission surface 11b1) efficiently (without waste). The angle on the horizontal axis in FIG. 12 corresponds to the angle between 0 ° and 90 ° shown in FIG.

  In the present embodiment, based on the above knowledge and the like, the light beams reaching the respective ranges (Z0 to 5, Z5 to 10, Z10 to Z15, Z15 to 20, Z20 to 25) on the Z axis are guided to the light guide plate main body 11b (the first one). In order to make it efficiently (without waste) incident on the two exit surfaces 11b1), as shown in FIGS. 13, 14, and 15 (a) to (d), Z is placed between the light guide plate unit 10 and the projection lens 20. A plurality of reflecting surfaces 30a to 30e were arranged at positions corresponding to the respective ranges on the axis.

  As shown in FIG. 15A and the like, each of the reflecting surfaces 30a to 30e has an axial direction of the cylindrical lens portion 21a that has substantially the same length as the axial length of the cylindrical lens portion 21a (FIG. 15A). It is a flat reflection surface extending in the middle and left and right directions. Each of the reflecting surfaces 30a to 30e receives light (particularly light including peak light intensity) irradiated from the light guide plate body 11b (second emitting surface 11b1) that has reached the reflecting surfaces 30a to 30e. It arrange | positions with the inclination attitude | position so that it may reflect toward the light-guide plate 10 (2nd output surface 11b1) just above 30e.

  In the case of forming a clear cut-off line, as shown in FIGS. 14 and 15A to 15D, the focal lines FL of the left and right lens portions 21b and 21c are provided on both sides of the reflecting surfaces 30a to 30e, respectively. It is desirable to place a main shade 40 having an upper edge 41 extending along the edge. For example, as shown in FIG. 16, the focal line FL is included in a horizontal plane (or a horizontal plane parallel to the horizontal plane) including the optical axis AX (rotation axis) of the left and right lens portions 21b and 21c, and the optical axis. A plurality of parallel rays having different inclination angles with respect to AX (rotation axis) (FIG. 16 illustrates a plurality of parallel rays L1 to L4) are incident on the left and right lens portions 21b and 21c from the exit surface side of the left and right lens portions 21b and 21c. And a focal point group formed when the light is emitted from the incident surface 22 side. By disposing the main shade 40 with the upper end edge 41 along the focal line FL, it is possible to form a light distribution pattern having a clear cut-off line. However, even if only the main shade 40 is arranged without installing the plurality of reflecting surfaces 30a to 30e, the illusion light P1 in FIGS. 11A and 11B does not disappear, and the plurality of reflecting surfaces Only when 30a to 30e are installed, the illusion light P1 can be eliminated.

  According to the vehicular lamp 100 of the present embodiment, the plurality of reflecting surfaces 30a to 30e having the above-described configuration are disposed between the light guide plate unit 10 and the projection lens 20 (see FIGS. 13 to 15), thereby providing a light guide plate. 10 (the first emission surface 11a1 and the second emission surface 11b1) and a plurality of light rays (see FIG. 9) spreading in the left-right direction are incident on the lower half of the optical axis AX of the cylindrical lens portion 21a. Are reflected by the plurality of reflecting surfaces 30a to 30e toward the light guide plate 10 (second exit surface 11b1) immediately above the reflecting surfaces 30a to 30e. For this reason, it becomes possible to prevent the light beam spreading in the left-right direction from entering the lower half of the optical axis AX of the cylindrical lens portion 21a. For this reason, it becomes possible to prevent the dazzling light P1 resulting from the light rays spreading in the left-right direction entering the lower half of the optical axis AX of the cylindrical lens portion 21a (see FIG. 17). That is, according to the vehicular lamp 100 using the plurality of reflecting surfaces 30a to 30e of the present embodiment, no dazzling light appears above the horizon H, and a light distribution pattern suitable for a headlamp can be obtained. It becomes possible to provide a vehicular lamp.

  FIG. 17 is an example of a light distribution pattern formed by the vehicular lamp 100 using the plurality of reflecting surfaces 30a to 30e of the present embodiment. Referring to FIG. 17, the light distribution pattern formed by the vehicular lamp 100 using the plurality of reflecting surfaces 30 a to 30 e does not show illusion light more than the horizontal line H, and a light distribution pattern suitable for a headlamp is obtained. You can see that

  Moreover, according to the vehicle lamp 100 of the present embodiment, the plurality of reflecting surfaces 30a to 30e having the above-described configuration are disposed between the light guide plate unit 10 and the projection lens 20 (see FIGS. 13 to 15). The light beams reflected by the plurality of reflecting surfaces 30a to 30e toward the light guide plate 10 (second emission surface 11b1) immediately above the light incident on the inside of the light guide plate main body 11b, and the second back surface 11b2 (or outside of the second back surface 11b2). A portion of the light distribution pattern (see FIG. 17) reflected by the back-side reflection sheet 14 toward the projection lens 20 and reversed and enlarged by the projection lens 20 (see FIG. 17) is wide in the horizontal direction and the vertical direction. Appear as a light pattern). That is, according to the vehicular lamp 100 of the present embodiment, it is possible to reuse a light beam that spreads in the left-right direction.

  Further, according to the vehicular lamp 100 of the present embodiment, as shown in FIG. 3 and the like, the light guide plate body 11b is bent toward the projection lens 20 in the vicinity of the focal point F3 of the projection lens 20 with respect to the base end portion 11a. A reflection surface 11c as an elliptical reflection surface is formed between the first back surface 11a3 and the second back surface 11b2. For this reason, as shown in FIG. 7, the light from the light source 12 that is incident on the light guide plate 11 from the incident surface 11a1 and guided therethrough and reaches the reflecting surface 11c is reflected by the reflecting surface 11c to the first emitting surface 11a2. In addition, the light is reflected toward the vicinity of the focal point F3 (second focal point F2) of the projection lens 20 so that the incident angle with respect to the second outgoing surface 11b1 (mainly the first outgoing surface 11a2) is within the critical angle, and the first outgoing surface 11a2. And it radiates | emits from the 2nd output surface 11b1. Thereby, on the first emission surface 11a2 and the second emission surface 11b1, a luminance distribution including a high luminance part higher than the surrounding luminance (a high luminance part corresponding to a light distribution pattern including the maximum luminous intensity required for the headlamp is obtained. Brightness distribution). The luminance distribution including the high luminance part is inverted and enlarged and projected by the projection lens 20. Thereby, it is possible to form a light distribution pattern including the maximum luminous intensity required for the headlamp.

  Further, according to the vehicular lamp 100 of the present embodiment, as shown in FIG. 3 and the like, the light guide plate main body 11b is bent toward the projection lens 20 in the vicinity of the focal point of the projection lens 20 with respect to the base end portion 11a. Yes. For this reason, it becomes possible to shorten the dimension of the optical axis AX direction of the light-guide plate main body 11b. For this reason, the depth dimension of the vehicular lamp 100 can be made shorter than before.

  In addition, according to the vehicular lamp 100 of the present embodiment, the plurality of reflecting surfaces 30a to 30e are light beams directed toward the lower half of the optical axis AX of the cylindrical lens portion 21a that have reached the reflecting surfaces 30a to 30e, respectively. Are arranged in an inclined posture so as to be reflected toward the light guide plate 10 (second emission surface 11b1 thereof) immediately above the reflection surfaces 30a to 30e (see FIG. 13 and the like). For this reason, the light rays traveling toward the lower half of the optical axis AX of the cylindrical lens portion 21a are efficiently (without waste) sent to the light guide plate 10 (second emission surface 11b1) directly above by the plurality of reflection surfaces 30a to 30e. ) Can be incident.

  Next, a modified example will be described.

  Although the said embodiment demonstrated the example in which the space was formed between several reflective surfaces 30a-30e (refer FIG. 13, FIG. 14, etc.), this invention is not limited to this. For example, as shown in FIG. 18, you may block | close between several reflective surfaces 30a-30e.

  Moreover, although the said embodiment demonstrated the example in which the some reflective surfaces 30a-30e are five, this invention is not limited to this. For example, a plurality of reflective surfaces of less than 5, or 6 or more may be employed.

  Moreover, although the said embodiment demonstrated the example in which the some reflective surfaces 30a-30e are flat plate-shaped reflective surfaces, this invention is not limited to this. For example, a curved reflecting surface may be adopted as the plurality of reflecting surfaces.

  In the above-described embodiment, the plurality of reflection surfaces 30a to 30e have been described so as to be reflected toward the light guide plate 10 (second emission surface 11b1) directly above, but the present invention is not limited to this. For example, the plurality of reflecting surfaces 30a to 30e are configured to reflect toward a portion where light intensity is required in the light distribution pattern (for example, the reflecting surfaces 30a to 30e that adjust the inclination angles of the plurality of reflecting surfaces 30a to 30e). 30e may be adjusted).

  The above embodiment is merely an example in all respects. The present invention is not construed as being limited to these descriptions. The present invention can be implemented in various other forms without departing from the spirit or main features thereof.

  DESCRIPTION OF SYMBOLS 100 ... Vehicle lamp, 10 ... Light guide plate unit, 11 ... Light guide plate, 11a ... Base end part, 11a1 ... Incident surface (light-incidence surface), 11a2 ... Output surface, 11a3 ... Back surface, 11b ... Light guide plate main body, 11b1 ... Output surface, 11b2 ... back surface, 11b light guide plate body, 11b3 ... prism surface, 11b4 ... prism surface, 11c ... reflection surface, 11d ... prism, 12 ... light source, 12a ... light emitting surface, 13 ... front side reflection sheet, 13a ... top edge , 14 ... back side reflection sheet, 20 ... projection lens, 21 ... exit surface, 21a ... cylindrical lens surface, 21b ... right lens surface, 21c ... left lens surface, 22 ... entrance surface, 30 ... auxiliary shade (light-shielding shade), 31 ... reflecting surface, 40 ... main shade, 41 ... upper edge, 50 ... auxiliary reflecting surface, 60 ... prism

Claims (2)

In a vehicle lamp provided with a light guide plate made of a transparent material in the visible light region, a light source and a projection lens,
The light guide plate includes a base end portion, a light guide plate main body bent toward the projection lens in the vicinity of the focus of the projection lens with respect to the base end portion, and a reflective surface.
The base end includes an incident surface, a first exit surface, and a first back surface on the opposite side.
The light guide plate main body includes a second emission surface, a second back surface on the opposite side, and a prism surface,
The incident surface is a light incident surface for allowing light rays emitted from the light source to enter the light guide plate;
The first emission surface and the second emission surface are formed on the projection lens side,
The first back surface and the second back surface are formed on the side opposite to the projection lens,
The reflecting surface is formed between the first back surface and the second back surface or on the first back surface, and the prism surface is incident on the light guide plate from the incident surface and guided. The light from the light source that has reached the prism surface is reflected toward the first emission surface and the second emission surface so that the incident angle with respect to the first emission surface and the second emission surface is within a critical angle, A lens cut surface for forming a luminance distribution on the first emission surface and the second emission surface;
The reflection surface is incident and guided from the incident surface into the light guide plate, and a light beam from the light source that has reached the reflection surface is incident at a critical angle with respect to the first and second emission surfaces. A reflection surface for reflecting toward the focal point of the projection lens so as to be inside, and forming a high-luminance portion higher than the surrounding luminance on the first emission surface and the second emission surface,
The projection lens is a lens for reversing and enlarging the luminance distribution formed on the first emission surface and the second emission surface to form a predetermined light distribution pattern, and includes at least a cylindrical lens portion. And
further,
Of the light rays from the light source that are disposed between the light guide plate and the projection lens and are irradiated from the light guide plate, direct the light rays toward the lower half of the optical axis of the cylindrical lens portion toward the light guide plate. A vehicular lamp comprising a plurality of reflecting surfaces for reflecting light.   The plurality of reflecting surfaces are arranged in an inclined posture so as to reflect a light beam directed to the lower half of the optical axis of the cylindrical lens unit that has reached the reflecting surface toward a light guide plate immediately above the reflecting surface. The vehicular lamp according to claim 1, wherein the vehicular lamp is provided.