JP2010129311A - Lighting fixture for vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lighting fixture for a vehicle with a light guide plate, capable of forming a light distribution pattern that includes maximum luminance required for a headlamp and of reducing the depth dimension thereof than the conventional types. <P>SOLUTION: The lighting fixture for a vehicle includes a light guide plate of a material transparent in a visible light band, a light source, and a projection lens. The light guide plate includes a light guide plate body which is bent toward the projection lens side and a reflecting surface; a base end part includes an incidence surface, a first emission surface, and a first rear surface on the opposite side thereof; the light guide plate body includes a second emission surface, a second rear surface on the opposite side thereof, and a prism surface; the reflecting surface is a surface to form a high-luminance portion which is brighter than the surroundings of the first emission surface and the second emission surface. The projection lens is a lens for inverting, magnifying and projecting the luminance distribution formed on the first emission surface and the second emission surface, and for forming a predetermined light distribution pattern. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a vehicular lamp using a light guide plate, and more particularly to a vehicular lamp that can form a light distribution pattern including the maximum luminous intensity.

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

  As shown in FIG. 27A, 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. 27B 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, the light guide plate 210 is a flat light guide plate and the light source 220 faces the end surface of the light guide plate 210 as shown in FIG. 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.

  Further, as shown in FIG. 28, 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 vehicle lamp There is also a problem that the depth dimension of 200 cannot be shortened any further.

  The present invention has been made in view of such circumstances, and provides a vehicular lamp using a light guide plate capable of forming a light distribution pattern including the maximum luminous intensity required for a headlamp. Is the first problem. 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 ever.

  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. Lens, wherein the first emission surface and the second reversing the formed intensity distribution on the exit surface, expanding and projecting a lens for forming a predetermined light distribution pattern.

  According to the first aspect of the present invention, the light guide plate main body is bent toward the projection lens near 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). A reflection surface is formed on the back 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, the reflective surface has an elliptical system in which the first focal point is set near the light source and the second focal point is set near the focal point of the projection lens. It is a reflective surface.

  According to the second 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). 1), an elliptical reflecting surface is formed. For this reason, a light beam from a light source that is incident on the light guide plate from the incident surface and is guided and reaches the elliptical reflecting surface has a critical incident angle with respect to the first and second emitting surfaces by the elliptical reflecting surface. The light is reflected toward the vicinity of the focal point (second focal point) of the projection lens so as to be within the corner, 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 portion 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 a third aspect of the present invention, in the second aspect of the present invention, the first focal point is formed by refracting a light beam from the light source incident and guided into the light guide plate at the incident surface. It is characterized in that it is set near the center of the virtual image.

  According to the invention described in claim 3, by setting the first focal point in the vicinity of the center of the virtual image, a higher maximum luminous intensity can be obtained, and a light distribution pattern suitable for the headlamp can be formed.

  According to a fourth aspect of the present invention, in the first aspect of the present invention, the reflecting surface is a reflecting surface having a planar shape or a curved shape having the same inclination angle as the second back surface.

  According to the fourth 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). On the first back surface, a reflection surface having a planar shape or a curved surface having the same inclination angle as that of the second back surface is formed. For this reason, the light beam from the light source that has entered the light guide plate from the incident surface and is guided to reach the reflection surface (the reflection surface having the same inclination angle as that of the second back surface or a curved surface) is reflected on the reflection surface. The light is reflected toward the vicinity of the focal point of the projection lens so that the incident angles with respect to the first emission surface and the second emission surface are within the critical angle, and 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 portion 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.

  The invention according to claim 5 is the invention according to claim 1, wherein the reflection surface is a reflection surface having a planar shape or a curved shape having a different inclination angle from the second back surface.

  According to the fifth 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). On the first back surface, a reflection surface having a planar shape or a curved surface shape having a different inclination angle from the second back surface is formed. For this reason, the light from the light source that has entered the light guide plate from the incident surface and is guided and guided to the reflection surface (a reflection surface having a plane shape or a curved surface having a different inclination angle from the second back surface) is reflected by the reflection surface. The light is reflected toward the vicinity of the focal point of the projection lens so that the incident angles with respect to the first emission surface and the second emission surface are within the critical angle, and are 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 portion 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.

  The invention according to claim 6 is the invention according to claim 4 or 5, wherein a light beam from the light source is incident on the reflection surface so that an incident angle with respect to the first emission surface and the second emission surface is within a critical angle. A prism surface is formed on the first emission surface and the second emission surface so as to form a high-luminance portion that is higher than the surrounding luminance. It is characterized by.

  According to the sixth 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). A prism surface is formed on the back surface. For this reason, the incident light with respect to the first emission surface and the second emission surface is critical for the light beam from the light source incident on the light guide plate from the incident surface and guided to reach the reflection surface (prism surface). The light is reflected toward the focal point of the projection lens so as to be within the corner, 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 portion 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.

  The invention according to claim 7 is the invention according to any one of claims 1 to 6, wherein the first back surface and the second back surface are covered with a reflection sheet.

  According to the seventh aspect of the present invention, since the light from the light source transmitted to the outside from the first back surface and the second back surface is returned to the inside of the light guide plate again by the reflection sheet, the light use efficiency can be improved. It becomes.

  The invention according to an eighth aspect is the invention according to the seventh aspect, wherein the reflection sheet makes the light from the light source transmitted to the outside from the first back surface or the second back surface incident on the light guide plate again. And having a convex reflection surface on the outside for reflection so as to be incident on the projection lens through the second emission surface.

  According to the eighth aspect of the present invention, the light beam from the light source transmitted to the outside from the first back surface or the second back surface is incident again on the light guide plate by the reflective surface that is convex outward, and the second light exit surface. Therefore, the light utilization efficiency can be improved.

  The invention according to claim 9 is the invention according to any one of claims 1 to 8, wherein the first emission surface is covered with a reflection sheet having an upper end edge extending along a line corresponding to a horizontal line. It is characterized by that.

  According to the ninth aspect of the present invention, since the light from the light source transmitted to the outside from the first emission surface is returned to the inside of the light guide plate again by the reflection sheet, the light use efficiency can be improved. According to the ninth aspect of the present invention, since the first emission surface is covered with the reflection sheet having the upper edge extending along the line corresponding to the horizontal line, it is a clear cut-off line suitable for the low beam. It is possible to form a light distribution pattern having

  A tenth aspect of the present invention is the invention according to any one of the first to ninth aspects, wherein the first emission surface transmits a light beam from a light source that has reached the first emission surface to an end portion of the light guide plate body. It is characterized by being formed as a reflective surface that reflects toward the surface.

  According to the tenth aspect of the present invention, the light beam from the light source that has reached the first emission surface is reflected toward the end of the light guide plate body by the first emission surface and guided to the light guide plate body. Therefore, it is possible to improve the light utilization efficiency.

  According to an eleventh aspect of the present invention, in the invention according to any one of the first to tenth aspects, an inclination between the first emission surface and the second emission surface increases as the distance from the second emission surface increases. Thus, a curved surface inclined is formed.

  According to the eleventh aspect of the invention, the reflected light from the reflecting surface that transmits the curved surface formed between the first emitting surface and the second emitting surface is bent upward by the action of the curved surface. For this reason, the reflected light from the reflecting surface that passes through the curved surface hardly enters the lower half of the projection lens (for example, a cylindrical lens).

  For this reason, according to the eleventh aspect of the present invention, glare light caused by reflected light from the reflecting surface that passes through the curved surface is incident on the lower half of the projection lens (for example, a cylindrical lens) is prevented or reduced. It becomes possible.

The invention according to claim 12 is 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, wherein the light guide plate has a base end portion and a base end portion. A light guide plate body bent toward the projection lens in the vicinity of the focal point of the projection lens, and the base end portion includes an incident surface, a first emission 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 opposite to the second emission surface, and a prism surface, and the incident surface is configured to allow light emitted from the light source to enter the light guide plate. A light incident surface, wherein the first and second light exit surfaces are formed on the projection lens side, and the first and second back surfaces are formed on the opposite side of the projection lens. The prism surface is incident and guided from the incident surface into the light guide plate, and the light incident from the light source reaching the prism surface has a critical incident angle with respect to the first and second output surfaces. The projection lens is a lens cut surface for reflecting toward the first emission surface and the second emission surface so as to be within a corner and forming a luminance distribution on the first emission surface and the second emission surface, Is a brightness formed on the first emission surface and the second emission surface. Distribution inverted, enlarged projection, characterized in that it is a lens for forming a predetermined light distribution pattern.

  According to the twelfth aspect of the 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 the invention described in claim 12, by adjusting the prism angle of the prism surface, the luminance suitable for the headlamp (or a fog lamp other than the headlamp, for example) over almost the entire area of the first and second emission surfaces. A distribution (light flux divergence distribution) is formed, and this luminance distribution is inverted and magnified by a projection lens to form a predetermined light distribution pattern.

  ADVANTAGE OF THE INVENTION According to this invention, it becomes possible to provide the vehicle lamp using the light-guide plate which can form the light distribution pattern containing the maximum luminous intensity. In addition, it is possible to provide a vehicular lamp using a light guide plate that can make the depth dimension of the vehicular lamp shorter than before.

  Hereinafter, a vehicular lamp according to a first embodiment of the present invention will be described with reference to the drawings.

  FIG. 1A is a top view of a vehicular lamp according to the first embodiment of the present invention, FIG. 1B is a front view of the vehicular lamp according to the first embodiment of the present invention, and FIG. FIG. 2 is a side view of the vehicular lamp according to the first embodiment of the present invention. 2A is a top view of a light guide plate unit used in the vehicular lamp according to the first embodiment of the present invention, and FIG. 1B is used in the vehicular lamp according to the first embodiment of the present invention. FIG. 1C is a side view of the light guide plate unit used in the vehicular lamp according to the first embodiment of the present invention. FIG. 3 is a side view of the vehicular lamp according to the first 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 with respect to the base end portion 11a. 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.

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 (the first emission surface 11 a 2 and the first light emitting surface 11 a 2 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 confirm that the light distribution pattern formed by the vehicular lamp 100 having the above configuration is a light distribution pattern suitable for a headlamp by performing a simulation using a predetermined program. did.

  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.

  As described above, 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 in the vicinity of the focal point F3 of the projection lens 20 with respect to the base end portion 11a. The reflective surface 11c as an elliptical reflective 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.

  Next, Modification 1 will be described.

  FIG. 11 is a diagram for pointing out problems that may occur in the first embodiment. FIG. 12 is a diagram for explaining the first modification.

  In the said 1st Embodiment, 1st output surface 11a2 which comprises a run-up area was demonstrated so that it might be a vertical surface (refer FIG. 3).

  However, as shown in FIG. 11, when the first exit surface 11a2 constituting the run-up section is a vertical surface, the first exit surface 11a2 depends on the length of the run-up section and the shape of the reflection surface 11c (elliptic reflection surface). Since the light beam from the light source 12 reflected by the light beam is reflected toward the incident surface 11a1 side by the reflection surface 11c (or the back-side reflection sheet 14), the light use efficiency decreases.

  In order to solve this problem, in the first modification, as shown in FIG. 12, the first emission surface 11a2 transmits the light beam from the light source 12 that has reached the first emission surface 11a2 to the end portion of the light guide plate body 11b. It is formed as a reflective surface that reflects toward the surface. FIG. 12 shows an example in which the first emission surface 11a2 is formed as a slope inclined toward the projection lens 20 (that is, a slope inclined such that the base end portion 11a becomes thicker as the distance from the incident surface 11a1 increases). The slope may be a curved surface or a flat surface.

  According to the first modification, the light beam from the light source 12 that has reached the first exit surface 11a2 is reflected by the first exit surface 11a2 toward the end of the light guide plate body 11b and guided to the light guide plate body 11b. Therefore, the light use efficiency can be improved.

  In FIG. 12, the front reflecting sheet 13 is arranged along the first emission surface 11a2 as an inclined surface. However, since the incident angle of the light beam from the light source 12 is usually larger than the critical angle, The light is totally reflected at one exit surface 11a2. For this reason, even if it does not cover the 1st output surface 11a2 with the front side reflection sheet 13, the light ray from the light source 12 does not permeate | transmit outside from the 1st output surface 11a2.

  Next, Modification 2 will be described.

  FIG. 13 is a diagram for pointing out problems that may occur in the first embodiment or the first modification. 14 and 25 are diagrams for explaining the second modification.

  As shown in FIG. 13, depending on the shape of the approach section, the light from the light source 12 reflected by the lower portion of the first back surface 11a3 and the first exit surface 11a2 constituting the approach section is reflected by the reflection surface 11c (or the reflection sheet 14). Since the light is reflected toward the incident surface 11a1, the light utilization efficiency may be reduced.

  In order to solve this problem, in the second modification, as shown in FIGS. 14 and 25, the space between the first emission surface 11a2 and the second emission surface 11b1 is from the light source 12 that has reached the first emission surface 11a2. Is formed as a reflection surface (corner R) that reflects the light beam toward the end of the light guide plate body 11b. The corner R is a curved surface that is inclined so that the inclination becomes larger as it approaches the second emission surface 11b1.

  According to the second modification, the reflected light from the lower part of the first back surface 11a3 that has reached the reflecting surface (corner R) is reflected toward the end of the light guide plate body 11b by the reflecting surface (corner R), Since the light is guided to the light guide plate body 11b, the light use efficiency can be improved.

  Further, according to the second modification, it is possible to prevent or reduce the incidence of light rays on the lower half of the cylindrical lens 21a (the range indicated by the slanted line in FIG. 1B), thereby reducing glare light. It becomes possible.

  That is, when light rays enter the lower half of the cylindrical lens 21a (the range indicated by the oblique lines in FIG. 1B) from the left or right direction or from an oblique direction, the light spreads above the horizontal line and becomes glare light as shown in FIG. . FIG. 26 shows a light distribution simulation result in the case where a light beam is incident on the lower half of the cylindrical lens 21a (the range indicated by the slanted line in FIG. 1B) from the left or right direction or from the slanted direction. This means that the light spreads and becomes glare light.

  However, according to the second modification, the reflected light from the reflecting surface 11c (or the reflecting sheet 14) that passes through the reflecting surface (corner R) acts on the reflecting surface (corner R) as shown in FIG. Is bent upward. For this reason, the reflected light from the reflecting surface 11c (or the reflecting sheet 14) that passes through the reflecting surface (corner R) hardly enters the lower half of the cylindrical lens 21a (the range indicated by the oblique lines in FIG. 1B). .

  Therefore, according to the second modification, the glare light caused by the reflected light from the reflecting surface 11c (or the reflecting sheet 14) that passes through the reflecting surface (corner R) is incident on the lower half of the cylindrical lens 21a. Can be prevented or reduced.

  Next, Modification 3 will be described.

  FIG. 15 is a diagram for pointing out problems that may occur in the first embodiment or the first and second modifications. FIG. 16 is a diagram for explaining the third modification.

  As shown in FIG. 15, light rays that are not totally reflected by the respective prism surfaces 11 b 3 but are transmitted to the outside from the second back surface 11 b 2 and returned to the inside of the light guide plate 11 by the back side reflection sheet 14 (for example, the light emitting surface 12 a of the light source 12). There is a ray from the end, not the center). Since this light beam is reflected by the back-side reflection sheet 14, it is emitted downward from the first and second emission surfaces 11 a 2 and 11 b 1 and does not enter the projection lens 20. For this reason, light utilization efficiency falls.

  In order to solve this problem, in the third modification, as shown in FIG. 16, the reflection sheet 14 causes the light from the light source 12 that has been transmitted to the outside from the second back surface 11 b 2 or the reflection surface 11 c to enter the light guide plate 11 again. It includes a reflecting surface 14a having an outward convex slope that is incident and reflected so as to be incident on the projection lens 20 via the second exit surface 11b1. The outwardly inclined reflective surface 14a covers, for example, the vicinity of the boundary between the second back surface 11b2 and the reflective surface 11c where total reflected light and transmitted light are mixed.

  According to the third modification, the light beam from the light source 12 that has been transmitted to the outside from the second back surface 11b2 or the reflecting surface 11c is incident on the light guide plate 11 again by the reflecting surface 14a that is inclined outward, and is emitted from the second light source. The light enters the projection lens 20 through the surface 11b1. For this reason, it becomes possible to improve light utilization efficiency.

  Next, Modification 4 will be described.

  FIG. 17 is a diagram for explaining the fourth modification.

  In the said 1st Embodiment, the reflective surface 11c (elliptic system reflective surface) demonstrated the example formed between the 2nd back surface 11b2 of the light-guide plate main body 11b, and the 1st back surface 11a3 of the base end part 11a (refer FIG. 3). However, the present invention is not limited to this.

  For example, as shown in FIG. 17, the reflection area of the reflection surface 11c may be expanded by forming the reflection surface 11c (elliptic reflection surface) up to the second back surface 11b2 of the light guide plate body 11b. According to the fourth modification, the light use efficiency can be improved.

  Next, Modification 5 will be described.

  FIG. 18 is a diagram for explaining the fifth modification.

  In the first embodiment, the reflective surface 11c is described as an elliptical reflective surface (see FIG. 3), but the present invention is not limited to this.

  For example, as shown in FIG. 18, the reflecting surface 11c may be a reflecting surface having a planar shape (or curved surface shape) having the same inclination angle as that of the second back surface 11b1. In this case, the light guide plate body 11b may be 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 so that the reflected light from the reflection surface 11c is directed to the focal point F3 of the projection lens 20. preferable.

  According to the fifth modification, the light enters the light guide plate 11 from the incident surface 11a1 and is guided, and reaches the reflecting surface 11c (a reflecting surface having the same inclination shape as that of the second back surface 11b2 or a curved surface). The light beam from the light source 12 is reflected by the reflecting surface 11c toward the vicinity of the focal point F3 of the projection lens 20 so that the incident angles with respect to the first emission surface 11a2 and the second emission surface 11b1 are within the critical angle, and the first emission. The light exits from the surface 11a2 and the second exit 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 portion 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.

  In FIG. 18, the light beam from the light source 12 may be totally reflected or transmitted by a part of the second back surface 11b2 (reflecting surface 11c) of the light guide plate body 11b. This is because the prism surface 11b3 is not formed on a part (reflective surface 11c) of the second back surface 11b2 of the light guide plate body 11b, so that the normal line of the back side reflection sheet 14 can be made the same as that of the second back surface 11b2. For this reason, even if the light passes through the second back surface 11b2, the direction of the light beam reflected by the back-side reflection sheet 14 and returned to the light guide plate 11 again is a part of the second back surface 11b2 of the light guide plate body 11b (reflective surface). This is because the direction of the light beam totally reflected in 11c) is the same.

  Next, Modification 6 will be described.

  FIG. 19 is a diagram for explaining the sixth modification.

  In the first embodiment, the reflective surface 11c is described as an elliptical reflective surface (see FIG. 3), but the present invention is not limited to this.

  For example, as shown in FIG. 19, the light incident from the light source 12 (and the reflected light from the reflective sheet 14) is incident on the reflecting surface 11c so that the incident angle with respect to the first emitting surface 11b1 and the second emitting surface 11a2 is within the critical angle. A prism surface 11b4 is formed on the first emission surface 11b1 and the second emission surface 11a2 so as to form a high luminance part higher than the surrounding luminance. It may be.

  According to the sixth modification, the light beam 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 (prism surface 11b4) is first emitted by the prism surface 11b4. The light is reflected toward the vicinity of the focal point F3 of the projection lens 20 so that the incident angles with respect to the surface 11a2 and the second emission surface 11b1 are within the critical angle, and are emitted from the first emission surface 11a2 and the second emission 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 portion 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.

  Next, Modification 7 will be described.

  20 and 21 are diagrams for explaining the modification example 7. FIG.

  In the first embodiment, the reflective surface 11c is described as an elliptical reflective surface (see FIG. 3), but the present invention is not limited to this.

  For example, as shown in FIG. 20, the reflective surface 11c may be a planar reflective surface having a different inclination angle from the second back surface 11b1, or, as shown in FIG. 21, a curved surface shape (with a predetermined curvature). A curved surface). When the reflecting surface 11c has the curved shape shown in FIG. 21, the light source 12 is larger than the thickness of the light guide plate 11, and reflects light rays from the light source 12 that are close to parallel rays toward the vicinity of the focal point F3 of the projection lens 20. It becomes possible.

  According to the seventh modification, the light source is incident and guided from the incident surface 11a1 to the inside of the light guide plate 11, and reaches the reflecting surface 11c (a reflecting surface having a plane shape or a curved surface shape having a different inclination angle from the second back surface 11b2). 12 is reflected by the reflection surface 11c toward the vicinity of the focal point F3 of the projection lens 20 so that the incident angles with respect to the first emission surface 11a2 and the second emission surface 11b1 are within the critical angle. The light is emitted from 11a2 and the second emission 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 portion 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.

  Next, Modification 8 will be described.

  22 and 23 are diagrams for explaining the eighth modification.

  In the said 1st Embodiment and each modification 1-6, although the prism surface 11b3 was demonstrated to the 2nd back surface 11b2 of the light-guide plate main body 11b (refer FIG. 4), this invention is not limited to this.

  For example, as shown in FIG. 22, the prism surface 11b3 may be formed on the second emission surface 11b1 of the light guide plate body 11b, or as shown in FIG. 23, the second back surface 11b2 and the second back surface 11b2 of the light guide plate body 11b. You may form on both surfaces of 2 output surface 11b1.

  Next, Modification 9 will be described.

  FIG. 24 is a diagram for explaining the modification 9.

  In the first embodiment, the projection lens 20 has been described as a solid lens body extending in the longitudinal direction, but the present invention is not limited to this.

  For example, as shown in FIG. 24, the projection lens 20 may be an aspherical convex lens. When an aspherical convex lens is used as the projection lens 20, it is preferable to arrange the light source 12 on a vertical section including the rotation axis (optical axis) of the projection lens 20 in order to obtain max luminous intensity. Moreover, in order to form the diffused light distribution pattern, it is preferable to arrange the light sources 12 on both sides of the light source 12 arranged on the vertical section.

  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.

(A) is a top view of the vehicular lamp according to the first embodiment of the present invention, (b) is a front view of the vehicular lamp according to the first embodiment of the present invention, and (c) is a view of the present invention. It is a side view of the vehicular lamp which is 1st Embodiment. (A) is a top view of a light guide plate unit used in the vehicular lamp according to the first embodiment of the present invention, and (b) is a light guide plate unit used in the vehicular lamp according to the first embodiment of the present invention. (C) is a side view of the light-guide plate unit used for the vehicle lamp which is 1st Embodiment of this invention. It is a side view of the vehicle lamp which is 1st Embodiment of this 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 surface 11a2, 11b1, and the measured light intensity distribution (actual value) of the conventional general projector type headlamp. It is a figure for pointing out the problem which may occur in 1st Embodiment. It is a figure for demonstrating the modification 1. FIG. It is a figure for pointing out the problem which may occur in 1st Embodiment or the modification 1. FIG. It is a figure for demonstrating the modification 2. FIG. It is a figure for pointing out the problem which may occur in 1st Embodiment or the modifications 1 and 2. FIG. FIG. 10 is a diagram for explaining a third modification. It is a figure for demonstrating the modification 4. FIG. FIG. 10 is a diagram for explaining a modification example 5; It is a figure for demonstrating the modification 6. FIG. FIG. 10 is a diagram for explaining a modification example 7; FIG. 10 is a diagram for explaining a modification example 7; FIG. 10 is a diagram for explaining a modification example 8; FIG. 10 is a diagram for explaining a modification example 8; It is a figure for demonstrating the modification 9. FIG. It is a figure for demonstrating the modification 2. FIG. It is a figure for demonstrating the modification 2. FIG. It is a figure for demonstrating the vehicle lamp using the conventional light-guide plate. It is a figure for demonstrating the vehicle lamp using the conventional light-guide plate.

Explanation of symbols

  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 ... Emitting surface, 11b2 ... back surface, 11b light guide plate body, 11b3 ... prism surface, 11b4 ... prism surface, 11c ... reflecting surface, 11d ... prism, 12 ... light source, 12a ... light emitting surface, 13 ... front reflecting 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

Claims (12)

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 to the projection lens side 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 reflective surface is formed between the first back surface and the second back surface or on the first back surface,
The prism surface is incident and guided from the incident surface to the inside of the light guide plate, and a light beam from the light source that has reached the prism surface is incident at a critical angle with respect to the first and second output surfaces. A lens cut surface for reflecting toward the first and second emission surfaces to form a luminance distribution on the first and second emission surfaces,
The reflection surface is guided by being incident on the light guide plate from the incident surface, and the incident angle with respect to the first emission surface and the second emission surface is a critical angle for the light beam from the light source that has reached the reflection surface. A reflecting 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 vehicle lamp according to claim 1, wherein the projection lens is a lens for inverting and enlarging the luminance distribution formed on the first emission surface and the second emission surface to form a predetermined light distribution pattern.   2. The vehicular lamp according to claim 1, wherein the reflection surface is an elliptical reflection surface having a first focal point set in the vicinity of the light source and a second focal point set in the vicinity of the focal point of the projection lens. .   The first focus is set in the vicinity of the center of a virtual image formed by refraction of a light beam from the light source incident and guided into the light guide plate at an incident surface. 2. A vehicular lamp according to 2.   2. The vehicular lamp according to claim 1, wherein the reflection surface is a reflection surface having a planar shape or a curved shape having the same inclination angle as that of the second back surface.   2. The vehicular lamp according to claim 1, wherein the reflection surface is a reflection surface having a planar shape or a curved shape having a different inclination angle from the second back surface.   The reflection surface reflects the light beam from the light source toward the focal point of the projection lens so that the incident angle with respect to the first emission surface and the second emission surface is within a critical angle, and the first emission 6. The vehicular lamp according to claim 4, wherein a prism surface for forming a high-luminance portion having a higher luminance than the surrounding luminance is formed on the surface and the second emission surface.   The vehicular lamp according to any one of claims 1 to 6, wherein the first back surface and the second back surface are covered with a reflection sheet.   The reflection sheet causes the light beam from the light source transmitted to the outside from the first back surface or the second back surface to enter the light guide plate again and to enter the projection lens through the second output surface. The vehicular lamp according to claim 7, wherein the vehicular lamp includes a convex reflecting surface on the outside to be reflected.   The vehicular lamp according to any one of claims 1 to 8, wherein the first emission surface is covered with a reflection sheet having an upper end edge extending along a line corresponding to a horizontal line.   The said 1st output surface is formed as a reflective surface which reflects the light beam from the light source which reached the said 1st output surface toward the edge part of a light-guide plate main body. The vehicle lamp according to any one of the above.   The curved surface inclined so that inclination may become large so that it is close to the said 2nd output surface between the said 1st output surface and the 2nd output surface is characterized by the above-mentioned. The vehicle lamp as described in 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 and a light guide plate main body bent toward the projection lens in the vicinity of the focal point of the projection lens with respect to the base end portion,
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 prism surface is incident and guided from the incident surface to the inside of the light guide plate, and a light beam from the light source that has reached the prism surface is incident at a critical angle with respect to the first and second output surfaces. A lens cut surface for reflecting toward the first and second emission surfaces to form a luminance distribution on the first and second emission surfaces,
The vehicle lamp according to claim 1, wherein the projection lens is a lens for inverting and enlarging the luminance distribution formed on the first emission surface and the second emission surface to form a predetermined light distribution pattern.

Images