JP4241336B2 - Display device - Google Patents

Description

  The present invention relates to a vehicular illumination device for illuminating a display device installed in a driver's seat of a vehicle so as to be visible, and is suitable for use in an automobile or the like.

  As a conventional vehicle lighting device, for example, a vehicle lighting device equipped in an automobile, a light guide body made of a light-transmitting material and including a plate-like light emitting portion, and a light guide body disposed on the back side of the light guide body A light source that irradiates light in a direction perpendicular to the surface of the light source, and a reflective surface that is provided on the outer peripheral side periphery of the light guide and reflects light from the light source incident on the light guide toward the light emitting part of the light guide There exists a thing of the structure provided with (refer patent document 1).

  In this case, the light from the light source reflected by the reflecting surface travels through the light emitting portion of the light guide, is reflected by the diffuse reflection layer provided on the back surface of the light guide, and is emitted from the surface of the light emitting portion. Then, this light transmissively illuminates a display unit disposed on the surface side of the light guide, such as a dial or a liquid crystal display.

  Moreover, the reflective surface provided in a light guide is formed as a plane.

Also, as another conventional vehicular lighting device, a configuration in which a light source is disposed so that light is incident on the light guide body from its end face by eliminating the reflecting surface of the light guide body and making the light guide body shape a simple plate shape. (See Patent Document 2).
JP-A-8-41974 JP 7-218296 A

  Generally, light is emitted radially from a light source, such as a light emitting diode.

  Therefore, in the vehicle lighting device described in Patent Document 1 described above, a part of the light emitted from the light source and incident on the light guide is incident on the reflection surface and is reflected and reflected in the light emitting portion of the light guide. Proceed toward the tip. Some light is repeatedly reflected several times in the light guide before entering the reflecting surface.

  Here, when the light traveling in the light guide is reflected on the light guide surface, if the incident angle on the light guide surface is larger than the total reflection angle (about 42 degrees in the case of acrylic resin), the incident light A part goes out of the light guide from the surface of the light guide. This light cannot be used as illumination light emitted from the light emitting portion of the light guide, and is lost.

  In addition, since the reflection surface is a flat surface, the incident angle when the reflected light of the light emitted from the light source and immediately incident on the reflection surface is incident on the surface of the light emitting portion of the light guide becomes larger than the total reflection angle described above. Sometimes. Also in this case, since a part of the incident light goes out of the light guide body from the surface of the light guide body, it cannot be used as illumination light emitted from the light emitting portion of the light guide body and is lost.

  Thus, in the conventional vehicle lighting device, a part of the light emitted from the light source is emitted outside the light guide before reaching the light emitting part of the light guide, and the light emission luminance of the light emitting part of the light guide is high. There is a problem of being lowered. In other words, there is a problem that the utilization rate of the light emitted from the light source is low.

  By the way, in general, an electric circuit portion of a display device to which a vehicle illumination device is mounted, for example, a printed circuit board, is disposed on the back side of the light guide substantially parallel to the light guide, and includes a light source of the vehicle illumination device. The constituent electric parts of the display device, such as a movement and a hybrid IC, are mounted.

  For this reason, when a light source is arranged on the end face of the light guide as in the vehicle illumination device described in Patent Document 2, it is possible to increase the utilization rate of the light emitted from the light source as illumination light. However, some member for electrically connecting the light source and the printed circuit board is required, resulting in an increase in the number of parts and an increase in assembly man-hours.

  The present invention has been made in view of the above-described problems, and facilitates electrical connection with the position of the light source as the back side of the light guide and the light emission direction as the direction perpendicular to the surface of the light guide, It is an object of the present invention to provide a vehicular illumination device that is devised in configuration and can obtain high utilization efficiency of light from a light source.

  In order to achieve the above object, the present invention employs the following technical means.

The vehicle lighting device according to claim 1 of the present invention is formed on a light guide plate formed of a light-transmitting material and provided with a substantially flat light-emitting portion, a light source disposed on the back side of the light guide plate, and the light guide plate. An incident surface for introducing light from the light source into the light guide plate; a reflection surface formed on the light guide plate for reflecting light from the light source incident on the light incident surface toward the light emitting portion; and a back surface of the light guide plate. A lighting device for a vehicle that includes a reflecting means, reflects light from a light source that is reflected by a reflecting surface and travels in a light emitting section, and reflects the light by the reflecting means to be emitted from the surface of the light guide plate. Arranged so as to be orthogonal to the surface of the light guide plate, the shape of the incident surface is formed as a curved surface that refracts light such that the direction of emission from the light source is the direction outside the reflective surface of the light guide plate so as to enter the reflective surface. together, the portion where the light toward the reflection surface of the incident surface is incident, The light is emitted from the light source and reflected by the reflecting surface intersects at almost one point in the light guide plate, and the distance between the point and the surface is larger than the plate thickness of the light emitting part. It is set as the curved surface which becomes small.

  In the conventional vehicular lighting device, a part of the light incident on the light guide from the light source is repeatedly reflected several times in the light guide before entering the reflecting surface. At this time, if the incident angle on the surface of the light guide is larger than the total reflection angle (about 42 degrees in the case of acrylic resin), part of the incident light goes out of the light guide from the surface of the light guide. This light cannot be used as illumination light emitted from the light emitting portion of the light guide, and is lost.

Further, in the conventional vehicular lighting device, since the reflecting surface shape reflecting surface is a flat surface, the reflected light of the light emitted from the light source and immediately incident on the reflecting surface is incident on the surface of the light emitting part of the light guide. The incident angle may be larger than the total reflection angle described above. Also in this case, since a part of the incident light goes out of the light guide body from the surface of the light guide body, it cannot be used as illumination light emitted from the light emitting portion of the light guide body and is lost. In addition, light is generally emitted radially from a light source, such as a light emitting diode. For this reason, a part of the light emitted from the light source may enter the light guide plate directly after entering the light guide plate without entering the reflection surface. In this case, since the incident angle on the surface becomes large, that is, exceeds the total reflection angle, the light exits from the light guide plate, and cannot be used as illumination light emitted from the light emitting portion of the light guide, resulting in a loss.

On the other hand, in the vehicle lighting device according to claim 1 of the present invention, the shape of the reflecting surface is such that the light emitted from the light source and reflected by the reflecting surface intersects at almost one point in the light guide plate, and is guided to this one point. The distance between the surfaces of the optical plates is assumed to be a curved surface that is smaller than the thickness of the light emitting portion. In addition, since most of the light emitted from the light source can be incident on the reflecting surface, the light incident on the reflecting surface after being refracted by the incident surface is not directly above the focal point after being reflected by the reflecting surface. , Pass through the immediate vicinity.

In this case, the fact that the light reflected by the reflecting surface intersects at almost one point in the light guide plate means that the intersection serves the same function as the light emission center of the light source. In other words, the position of the light source is moved to the position of the intersection. Furthermore, since the distance between the intersection and the surface of the light guide plate is smaller than the thickness of the light emitting part, it is almost the same as when the light source is arranged at the end of the light guide plate so that light enters the light guide from the end face. Ri Do to, most of the light emitted from the light source is converged on the focal point or its immediate section, the focus of the light source, the same effect as when moving words into the light guide body is obtained.

  Therefore, the vehicle lighting device can use light emitted from the light source as illumination light with high efficiency while facilitating electrical connection with the position of the light source as the back side of the light guide plate and the light emitting direction as the direction perpendicular to the surface of the light guide plate. Can be provided.

  According to a second aspect of the present invention, there is provided a vehicular illumination device in which a line of intersection between a plane perpendicular to the surface of the light guide plate including one point and the light emission center point of the light source and the reflective surface is convex outside the reflective surface. The structure is a simple curve.

  The reflection surface in the conventional vehicular lighting device is formed in a planar shape. Further, light is emitted radially from the light source. Therefore, when the light emitted from the light source is reflected by the reflecting surface, the reflected light diffuses radially.

  On the other hand, if the reflecting surface has a smooth curve that is convex outward of the reflecting surface as in the vehicular illumination device according to claim 2 of the present invention, the light is emitted radially from the light source and reflected by the reflecting surface. The reflected light can be made to converge to a certain point without spreading radially.

  Therefore, since the reflected light from the reflecting surface can intersect at almost one point in the light guide plate, it is possible to provide a vehicular illumination device that can use the light emitted from the light source as illumination light with high efficiency.

  According to a third aspect of the present invention, there is provided a lighting device for a vehicle, wherein an intersection line between a plane that includes one point and the light emission center point of the light source and is perpendicular to the surface of the light guide plate and the reflecting surface is focused on one point and the light emission center point of the light source. The configuration is an ellipse.

  In this case, when the light emitted radially from the light source is reflected by the reflecting surface, it always converges toward another focal point and travels radially after passing through the focal point. The light can be converged at one point in the light guide plate.

  Hereinafter, a case where the vehicle illumination device according to the present invention is applied to an illumination unit 1 for illuminating a liquid crystal display 101 mounted on an automobile combination meter 100 will be described with reference to the drawings.

  FIG. 1 is a partial front view of a combination meter 100 on which a lighting unit 1 according to an embodiment of the present invention is mounted.

  FIG. 2 is a partial cross-sectional view of the combination meter 100 on which the illumination unit 1 according to the embodiment of the present invention is mounted, that is, a cross-sectional view of the liquid crystal display 101 portion, and is a cross-sectional view taken along the line II-II in FIG.

  FIG. 3 is a schematic diagram illustrating a light traveling path in the light guide plate 2 of the illumination unit 1 according to the embodiment of the present invention.

  FIG. 4 is a schematic diagram for explaining an electric circuit configuration of the combination meter 100 on which the illumination unit 1 according to the embodiment of the present invention is mounted.

  The combination meter 100 is disposed at a position visible from the driver in front of the driver's seat of the automobile, and includes a liquid crystal display 101, a pointer instrument (not shown), etc., and the driver visually recognizes various information related to the automobile. It is displayed as possible.

  As shown in FIG. 2, the liquid crystal display 101 is fitted and attached to an opening hole 102 a provided in the dial plate 102 of the combination meter 100. In one embodiment of the present invention, the liquid crystal display 101 is used as a speedometer that displays the traveling speed of an automobile as a number as shown in FIG.

  On the back side of the liquid crystal display 101, that is, the lower side of FIG. 2, an illumination unit 1 for transmitting and illuminating the liquid crystal display 101 is disposed.

  As shown in FIG. 2, the illumination unit 1 includes a light guide plate 2, a light emitting diode 3 as a light source, and a printed board 4 on which the light emitting diode 3 is mounted. Note that an electric circuit portion of the combination meter 100 is also formed on the printed circuit board 4. That is, on the printed circuit board 4, in addition to the light emitting diode 3 which is a light source of the illumination unit 1, a movement for driving a pointer instrument (not shown) and a light emitting diode which is a light source for illuminating the dial 102 (not shown). Etc. are implemented.

  Next, the shape of the light guide 2, particularly the shapes of the reflecting surface 22 and the incident surface 21, which is a feature of the lighting unit 1 according to the embodiment of the present invention, will be described mainly based on FIG. 3.

  The light guide plate 2 is made of a translucent material, for example, a transparent polycarbonate resin. As shown in FIG. 3, the light guide plate 2 includes a substantially flat light emitting section 23, an incident surface 21 for introducing light from the light emitting diode 3 as a light source into the light guide plate 2, and a light emitting diode incident from the incident surface 21. 3 is provided with a reflecting surface 22 that reflects the light from 3 toward the light emitting unit 23.

  As shown in FIG. 2, the light emitting unit 23 is formed in a shape equivalent to the liquid crystal panel 101 so that the planar shape can reliably transmit and illuminate the entire area of the liquid crystal panel 101. Further, on the back surface 23a of the light emitting portion 23, a textured surface 23b, which is a diffuse reflection layer, is formed as a reflecting means. When light from the light emitting diode 3 enters the light emitting portion 23 through the reflecting surface 22, it is diffusely reflected by the embossed surface 23b, and the light is emitted upward from the surface 23c of the light emitting portion 23 in FIG. In the lighting unit 1 according to the embodiment of the present invention, the textured surface 23b is provided. However, the illumination unit 1 is not limited to the textured surface 23b, and is not limited to the textured surface 23b. (A silver color or the like) A printing layer may be provided.

  As shown in FIG. 3, the reflecting surface 22 is formed so that the intersecting line shape with the plane that includes the light emission center point 31 of the light emitting diode 3 and is perpendicular to the surface 23 c is an ellipse that protrudes outward from the reflecting surface 22. Has been. The ellipse shape is set so that one of the two focal points of the ellipse is the light emission center point 31 of the light emitting diode 3 and the other is the focal point 24 which is almost one point in the light guide plate 2. Has been. Therefore, when the light emitted from the light emitting diode 3, that is, the light emitted from the light emission center point 31 of the light emitting diode 3 is incident on the reflection surface 22 and reflected there, all of the light passes through the focal point 24. In other words, the light emitted from the light emission center point 31 of the light emitting diode 3 travels through the light guide plate 2 after being reflected by the reflecting surface 22 and converging again to one point of the focal point 24. In other words, the light emission center point 31 of the light emitting diode 3 can be brought into a state substantially equivalent to the case where it is installed at the position of the focal point 24 in the light guide plate 2. Further, as shown in FIG. 3, the position of the focal point 24 is inside the light emitting portion 23 of the light guide plate 2, that is, inside the plate-like portion, and the distance between the focal point 24 and the surface 23 c is the thickness of the light emitting portion 21. It is set to be half of the dimension t. As a result, the light reflected by the reflecting surface 22 and converged at the focal point 24 is diffused almost evenly into the light emitting portion 21, so that the light enters the back surface 23a, that is, the embossed surface 23b, which is a diffuse reflection layer, with high efficiency. Can be made. The positional relationship between the reflecting surface 22 and the light emitting diode 3 is set so that the optical axis 32 of the light emitting diode 3 passes through the reflecting surface 22 as shown in FIG.

  As shown in FIG. 3, the incident surface 21 is formed in a curved line with an intersecting line shape with a plane including the light emission center point 31 of the light emitting diode 3 and perpendicular to the surface 23 c. This curve shape will be described in detail.

  Here, a basic concept for setting the shape of the incident surface 21 in the light guide plate 2 of the illumination unit 1 according to the embodiment of the present invention will be described. Of the light emitted from the light emitting diode 3, the light traveling in the direction of the reflection surface 22 is shaped so as to be incident on the reflection surface 22 in a straight line from the light emission center point 31. In other words, the shape is such that it is not refracted as much as possible when passing through the incident surface 21. On the other hand, of the light emitted from the light emitting diode 3, the light traveling outward from the reflecting surface 22 is refracted so as to enter the reflecting surface 22.

  If the shape of the incident surface 21 is as described above, the light directed from the light emitting diode 3 toward the reflecting surface 22 can be reflected by the reflecting surface 22 and reliably pass through the focal point 24. . Further, the light traveling in the outward direction of the reflection surface 22 is also refracted in the direction of the reflection surface 22 by the incident surface 21 and reflected by the reflection surface 22.

  Thereby, most of the light emitted from the light emitting diode 3 can be converged on the focal point 24 in the light guide plate 2 and the vicinity thereof. In other words, the light emission center point 31 of the light emitting diode 3 can be brought into a state substantially equivalent to the case where it is installed at the position of the focal point 24 in the light guide plate 2.

  Here, the vicinity of the focal point 24 means that the light emission luminance at the convergence point is equivalent to the light emission luminance at the light emission center point 31 of the light emitting diode 3 when the light emitted from the light emitting diode 3 and reflected by the reflecting surface 22 converges. For example, it is the inside of a sphere C whose diameter is half of the thickness t of the light emitting portion 23 with the focal point 24 as the center.

  Next, a specific shape of the incident surface 21 will be described.

  First, consider a limit line 33 that is a line connecting the light emission center point 31 and the end of the reflecting surface 22 on the light emitting portion 21 side.

  Of the light emitted from the light emitting diode 3, the light ray on the right side of the limit line 33 in FIG. 3 can directly enter the reflecting surface 22. Therefore, a portion of the incident surface 21 where these light rays are incident has a shape that does not refract light when entering the light guide plate 2, in other words, a shape that makes the incident angle to the incident surface 21 almost 0 degrees. Is set. That is, as shown in FIG. 3, it is formed as a curve A that is a concave curve on the outside.

  On the other hand, of the light emitted from the light emitting diode 3 on the incident surface 21, the portion where the light beam on the left side of the limit line 33 in FIG. 3 enters can refract the incident light toward the reflecting surface 22. The shape is set. That is, as shown in FIG. 3, it is formed as a curve B that is a convex curve outward.

  Therefore, the light emitted from the light emitting diode 3 and incident on the light guide plate 2 from the curve A portion of the incident surface 21 is reflected by the reflecting surface 22 and passes through the focal point 24 as indicated by an arrow in FIG. Further, the light emitted from the light emitting diode 3 and incident on the light guide plate 2 from the curve B portion of the incident surface 21 is reflected by the reflecting surface 22 as shown by the arrow in FIG. Passing through a sphere C having a diameter of t / 2.

  The light emitting diode 3 that is a light source allows light to enter the light guide plate 2 on the back side of the light guide plate 2, that is, the lower side in FIG. 2, and the optical axis 32 of the light emitting diode 3 is orthogonal to the surface 23 c of the light guide plate 2. Are arranged. The light emitting diode 3 is mounted on a printed circuit board 4 disposed on the back side of the light guide plate 2.

  The printed board 4 is made of, for example, a glass epoxy board, and forms an electric circuit of the lighting unit 1. The printed circuit board 4 also forms an electric circuit section of the combination meter 100. In addition to the liquid crystal panel 101, the printed circuit board 4 is a movement (not shown) that is a driving section of a pointer instrument and a light source for illuminating the dial 102. A light emitting diode (not shown) or the like is mounted.

  Next, the electrical circuit configuration of the illumination unit 1 according to an embodiment of the present invention will be described based on the schematic diagram showing the electrical circuit configuration of FIG.

  The electrical component in the lighting unit 1 according to the embodiment of the present invention is the light emitting diode 3, and the light emitting diode 3 is controlled to be turned on / off by the control device 103 of the combination meter 100 in which the lighting unit 1 is mounted. Yes.

  As shown in FIG. 4, power is always supplied from the battery 105 to the control device 103. Further, the control device 103 is connected to an ignition switch 104 so as to be able to detect its operating state (ON or OFF). Based on the detection result of the operation state of the ignition switch 104, the control device 103 performs lighting / extinguishing control of the light emitting diode 3 and the other light emitting diodes 106 mounted on the combination meter 100. Furthermore, various sensors for detecting the state of the vehicle are connected to the control device 103 so that detection signals can be input, and various types for displaying the state of the vehicle on the combination meter 100 based on the detection signals. The display means is connected by the control means 103 so that it can be driven. As various sensors, a vehicle speed sensor 107, a liquid level detection sensor 108 for detecting the liquid level in the fuel tank, a water temperature sensor 109 for detecting the cooling water temperature of the engine, and the like are connected. On the other hand, as various display means, movements 110 and 111 for driving a pointer instrument are connected in addition to the liquid crystal display 101 for displaying the vehicle speed.

  When the ignition switch 104 is turned on by the driver, the control device 103 turns on the light emitting diode 3. Thereby, the illumination unit 1 will be in a lighting state. At the same time, the control device 103 drives the liquid crystal display 101 so as to display the speed of the vehicle based on the detection signal from the vehicle speed sensor 107. Therefore, the speed of the automobile displayed on the liquid crystal display 101 is transmitted and illuminated by the irradiation light from the illumination unit 1 and is clearly recognized by the driver.

  In the illumination unit 1 according to the embodiment of the present invention described above, the reflecting surface 22 of the light guide plate 2 has an intersecting line shape with a plane including the light emission center point 31 of the light emitting diode 3 and perpendicular to the surface 23c. As an ellipse that protrudes outward from 22, one of the two focal points included in the ellipse is the light emission center point 31 of the light emitting diode 3, and the other is within the light guide plate 2, that is, the light emitting unit 23. It was formed to be one point (focal point 24).

  In this case, when the light emitted radially from the light emission center point 31 of the light emitting diode 3 is incident on the light guide plate 2, it is reflected by the reflecting surface 22 and converges again at one point of the focal point 24, and then proceeds through the light guide plate 2. It will be. In other words, the light emission center point 31 of the light emitting diode 3 can be brought into a state substantially equivalent to the state where the light emission center point 31 is installed at the position of the focal point 24 in the light guide plate 2.

  As a result, a decrease in illumination efficiency in a conventional vehicle lighting device, that is, a decrease in utilization efficiency as illumination light due to light transmitted from the light source entering the light guide plate and then transmitted to the outside of the light guide plate is suppressed. The illumination unit 1 that can use the light emitted from the diode 3 as illumination light with high efficiency can be realized.

  Furthermore, in the illumination unit 1 according to an embodiment of the present invention, the distance between the focal point 24 in the light guide plate 2 and the surface 23c is set to be smaller than the plate thickness t of the light emitting unit 23 and in detail approximately half of the plate thickness t. did.

  With this configuration, the light emitting diode 3 is almost the same as the case where light is incident on the light guide plate 2 from the end face of the light guide plate 2, that is, the end face of the light emitting portion 23. The converged light is diffused almost uniformly into the light emitting unit 23.

  Accordingly, the light-emitting diode 3 can be easily connected to the light-guide plate while eliminating the complication of the electrical connection between the light-emitting diode 3 and the printed circuit board 4, which is a drawback when the light-emitting diode 3 is disposed on the end face of the light-guide plate 2. The lighting unit 1 can be realized in which the effect of the arrangement on the end face 2, that is, the light emitted from the light emitting diode 3 can be used as the illumination light with high efficiency.

  Further, in the illumination unit 1 according to the embodiment of the present invention, the shape of the incident surface 21 is changed to the light emitted from the light emitting diode 3 toward the outside of the reflecting surface 22, that is, the limit line 33 in FIG. The portion where the light on the left side is incident is formed in a curved shape convex outward so that the incident light is refracted toward the reflecting surface 22. Further, of the light emitted from the light emitting diode 3, the light traveling toward the reflection surface 22, that is, the portion on the right side of the limit line 33 in FIG. 2 is incident on the reflection surface 22 in a straight line from the light emission center point 31. Therefore, the light guide plate 2 is formed in a shape that does not refract light when incident on the light guide plate 2, in other words, a concave curved shape on the outside so that the incident angle to the incident surface 21 is approximately 0 degrees.

  As a result, most of the light emitted radially from the light-emitting diode 3 can be converged at or near the focal point 24, so that the illumination unit 1 that can use the light emitted from the light-emitting diode 3 as illumination light with high efficiency can be obtained. Can be realized.

  In the illumination unit 1 according to the embodiment of the present invention described above, the number of the light emitting diodes 3 as light sources is not particularly limited. Therefore, the number of the light emitting diodes 3 may be one or more as required.

  In the illumination unit 1 according to the embodiment of the present invention described above, the light-emitting diode 3 is used as the light source. However, the light-emitting diode 3 is not limited to the light-emitting diode 3, and other types of light sources such as light bulbs and discharges are used. A tube, an EL panel, or the like may be used.

  Moreover, although one Embodiment of this invention demonstrated above has shown as an example the case where it applies to the illumination unit 1 for the liquid crystal display 101 transmission illumination of the combination meter 100 mounted in a motor vehicle, liquid crystal display 101 transmission is shown. You may use for uses other than the use for illumination, for example, for the transmitted illumination of the part corresponding to the various pointer instruments of the dial 102 of the combination meter 100.

  Moreover, you may use the illumination unit 1 by one Embodiment of this invention demonstrated above for the illumination of the display apparatus mounted in motor vehicles other than the combination meter 1. FIG.

It is a partial front view of the combination meter 100 in which the illumination unit 1 by one Embodiment of this invention is mounted. It is a fragmentary sectional view of combination meter 100 with which lighting unit 1 by one embodiment of the present invention is mounted, ie, a sectional view of a portion of liquid crystal display 101, and is a sectional view taken along line II-II of FIG. It is a schematic diagram explaining the advancing path | route of the light in the light-guide plate 2 of the illumination unit 1 by one Embodiment of this invention. It is a schematic diagram explaining the electric circuit structure of the combination meter 100 in which the illumination unit 1 by one Embodiment of this invention is mounted.

Explanation of symbols

1 Lighting unit (vehicle lighting system)
2 Light guide plate 21 Incident surface 22 Reflecting surface 23 Light emitting portion 23a Back surface 23b Textured surface (reflecting means)
23c Surface 24 Focus (one point)
3 Light emitting diode (light source)
31 Light emission center point 32 Optical axis 33 Limit line 4 Printed circuit board 100 Combination meter 101 Liquid crystal display 102 Dial 102a Through hole 103 Control device 104 Ignition switch 105 Battery 106 Light emitting diode 107 Vehicle speed sensor 108 Liquid level detection sensor 109 Water temperature sensor 110, 111 Movement A Curve B Curve C Sphere t Thickness

Claims (3)

A light guide plate formed of a light-transmitting material and provided with a substantially flat light-emitting portion;
A light source disposed on the back side of the light guide plate;
An incident surface formed on the light guide plate for introducing light from the light source into the light guide plate;
A reflective surface that is formed on the light guide plate and reflects light from the light source incident from the incident surface toward the light emitting unit;
And reflecting means formed on the back surface of the light guide plate,
A vehicle lighting device that reflects light from the light source that is reflected by the reflecting surface and travels through the light emitting unit by the reflecting means to be emitted from the surface of the light guide plate,
The light source is arranged so that its optical axis is orthogonal to the surface of the light guide plate,
The incident surface shape is formed as a curved surface that refracts light such that an emission direction from the light source is an outer direction of the reflection surface of the light guide plate so as to be incident on the reflection surface. The portion where the light toward the reflecting surface is incident is formed in a concave curved shape on the outside,
The reflection surface is such that light emitted from the light source and reflected by the reflection surface intersects at almost one point in the light guide plate, and the distance between the point and the surface is smaller than the plate thickness of the light emitting unit. A vehicular lighting device characterized by being formed as a curved surface. The line of intersection between the plane including the one point and the light emission center point of the light source and perpendicular to the surface of the light guide plate and the reflection surface is a smooth curve convex outward of the reflection surface. The lighting device according to claim 1. The intersection line between the plane including the one point and the light emission center point of the light source and perpendicular to the surface of the light guide plate and the reflection surface is an ellipse having the focal point at the light emission center point of the one point and the light source. The lighting device according to claim 1.

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