JP2004284393A - License plate lighting system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lighting system capable of effectively enhancing visibility of a license plate by simple constitution. <P>SOLUTION: This lighting system is constituted by combining a light source and a rod-shaped or frame-shaped light guide body introducing light of the light source and radiating the introduced light to the outside via a side surface arranged on a display surface side of the license plate along an outer edge of the license plate. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
[Industrial applications]
The present invention relates to a lighting device used for lighting a vehicle license plate.
[0002]
[Prior art]
Light is applied to a display surface of a license plate of a vehicle in order to enhance visibility at night or the like. In such a front light type lighting method, a method of directly irradiating the license plate directly with light from a light source installed above, below, or on the side of the license plate is generally used. A method has also been proposed in which light is converted into planar light using a light guide plate (light guide) and then used as illumination light. For example, a light guide is installed so as to cover the display surface of the license plate, and light from a light source is introduced from above the light guide, thereby emitting planar light from the surface of the light guide facing the license plate to license the license plate. A license plate lighting device that illuminates a plate has been proposed (see Patent Document 1).
On the other hand, there has been proposed a configuration in which a plurality of light emitting diodes are arranged so as to surround a license plate in a spaced state, and the light of these light emitting diodes is used to improve the visibility of the license plate (Patent Document 2). See).
[0003]
[Patent Document 1]
US Pat. No. 5,150,960 [Patent Document 2]
JP-A-9-58338
[Problems to be solved by the invention]
In the lighting device disclosed in Patent Document 1, since a light guide (light guide) installed to cover the entire surface of the license plate is used, the lighting device becomes considerably heavy, and its handling (particularly, attaching and detaching work) is difficult. . In addition, in consideration of replacing the license plate after installing the lighting device, it is necessary to provide a light guide opening / closing mechanism, which complicates the configuration. Furthermore, in order to ensure good visibility for a long period of time, it is necessary to seal the license plate and the light guide to prevent moisture and dust from entering between them. Is required.
On the other hand, in the configuration disclosed in Patent Literature 2, since the light of each light emitting diode directly illuminates the license plate, the irradiation efficiency is low, and thus a good lighting effect can be obtained despite the large number of light emitting diodes used. There was no one. In addition, the number of light emitting diodes to be used is large, and the manufacturing cost must be high. Further, a part of the light emitted from the light emitting diode goes forward, not in the direction of the license plate, and is directly viewed, giving glare to the observer. As a result, the visibility of the license plate is rather lowered.
The present invention has been made in view of the above problems, and an object of the present invention is to provide a lighting device with a simple configuration capable of effectively improving the visibility of a license plate.
[0005]
[Means for Solving the Problems]
The present invention provides the following configuration to achieve the above object.
A light source, and a rod-shaped or frame-shaped light guide that introduces light from the light source and externally radiates the introduced light through a part of the side surface such that a part of the side surface is along an outer edge of the license plate. And a light guide disposed on the display surface side of the license plate.
[0006]
According to the above configuration, the light from the light source does not directly illuminate the license plate, but is illuminated by light emitted from a part of the side surface of the light guide after being once introduced into the light guide. That is, illumination is performed by light converted into a linear or planar shape by the light guide. By the action of such a light guide, light having uniform illuminance over a wide range illuminates the license plate. Therefore, the visibility of the license plate is effectively improved. On the other hand, a light guide such as a rod is arranged along the outer edge of the license plate, not along the entire surface of the license plate, and the license plate is illuminated by light emitted from the side surface of the light guide. Therefore, the amount of the light guide used is reduced, and as a result, the weight of the lighting device is reduced and the manufacturing cost is reduced. In addition, by arranging the light guide on the display surface side of the license plate such that the side surface is along the outer edge of the license plate, the license plate can be attached and detached without moving the light guide. That is, the lighting device is excellent in the workability of attaching the license plate. Further, since the license plate can be attached and detached in this manner, a special structure for attaching and detaching the license plate is not required, and the entire configuration is simplified. The simplification of the configuration also achieves a further reduction in manufacturing cost.
[0007]
BEST MODE FOR CARRYING OUT THE INVENTION
(light source)
As the light source, an LED (light emitting diode), a light bulb (bulb), a fluorescent lamp, a cold cathode tube, or the like can be used. Among them, it is preferable to use an LED. The LED light source is a light source suitable for continuous lighting for a long time because of its low power consumption and heat generation and long life. In addition, because of its small size, the space for the light source is small, and the lighting device of the present invention can be reduced in size and thickness. This also improves the handling of the lighting device. In addition, since the LED is resistant to vibration and impact, there is an advantage that a highly reliable lighting device can be configured.
[0008]
The type of the LED is not particularly limited, and various types such as a bullet type and a chip type can be adopted. The emission color of the light source used is not particularly limited, and a light source that emits light in a visible region such as white, red, orange, green, and blue can be used. Preferred light sources include those that emit white light. This is because, if a light source that emits white light is employed, the numbers, characters, and background displayed on the license plate can be observed (visually recognized) in their original colors. On the other hand, if a light source of a color other than white is used, the design of the license plate can be changed, for example, by adding a color to the license plate, or the design can be enhanced.
[0009]
A light source that emits light in the ultraviolet region can also be used. In this case, a phosphor that receives light in the ultraviolet region and fluoresces can also be used. Note that a light source capable of emitting light in the visible region and the ultraviolet region may be used.
When a phosphor is used, for example, a layer containing the phosphor can be provided on the surface of the light guide. Such a layer containing a phosphor can be formed by printing or applying a phosphor-containing ink or paint, or by attaching a sheet containing a phosphor. Further, the phosphor can be contained in the light guide plate. In such a configuration, fluorescent light is generated in the light guide, and the fluorescent light is emitted from the light emitting surface of the light guide to perform illumination. When the phosphor is contained in the light guide, it is particularly preferable to use an organic phosphor. This is because if an organic phosphor is used, the transparency of the light guide plate can be maintained, and a clear lighting effect can be obtained.
[0010]
Instead of including the phosphor in the light guide, it may be included in the license plate to be illuminated. For example, a display portion (numerals, characters, and the like) of the license plate can be formed using a paint or ink containing a phosphor, or a layer containing a phosphor can be separately provided on the surface of the display portion. In such a configuration, the light in the ultraviolet region emitted from the light source irradiates the license plate via the light guide to excite the phosphor of the display unit. As a result, the display portion of the license plate is illuminated by fluorescent light.
[0011]
The kind of the phosphor is not particularly limited, and it can be adopted regardless of an organic type or an inorganic type. By using an organic phosphor, it is possible to obtain a fluorescent color light with a clear feeling as described above. On the other hand, when an inorganic phosphor is used, fluorescent light having a matte feeling can be obtained. Phosphors having various fluorescent colors can be employed.For example, phosphors having red, green, or blue fluorescent colors, which are the three primary colors of light, as well as phosphors that emit intermediate colors thereof can be used. . A plurality of phosphors can be used in combination. For example, a red phosphor, a green phosphor, and a blue phosphor can be mixed and used.
[0012]
The light source in the present invention may be configured using a plurality of LEDs, bulbs, and the like. In this case, a plurality of light sources of the same type can be used, or a combination of light sources having different emission colors can be used. By using a plurality of light sources, it is possible to obtain effects such as enhancement of illuminance or illumination of various luminescent colors by mixing colors of light. The number of light sources used can be determined by comprehensively considering the brightness of each light source, the size of the light guide, the required illuminance, and the like. As an example of using a plurality of light sources, there can be cited one in which three types of red LED, green LED, and blue LED are used in combination. According to such a light source, white light can be obtained by mixing colors of the LEDs. By controlling the light emission state and the light emission amount of each LED, light of a desired color can be obtained.
[0013]
A light source is arranged facing a position where light can be introduced into the light guide (for example, one or more end faces of the light guide). It is preferable that the light source is arranged to face the end surface of the light guide. In this way, the introduced light guides the light inside the light guide satisfactorily, so that light can be emitted from a wider area of the light emitting surface of the light guide, and the light is emitted with less illuminance unevenness. Can emit radiation. For example, when a rod-shaped light guide is used, a light source can be arranged so as to face each end face thereof.
In terms of light introduction efficiency and compactness of the device, it is necessary to design the light source to be arranged in a state close to the light guide or in a state buried in a hole formed in the light guide. preferable.
[0014]
(Light guide)
The light from the light source is introduced into the light guide. The light guide includes a surface for introducing light from the light source (light introduction surface) and a surface for emitting the introduced light to the outside (light emission surface). The light introduction surface is formed at a position (typically, a position facing the light source) where light from the light source irradiates the light guide. The light emitting surface is formed on a side surface facing the license plate so that light emitted from the light emitting surface can illuminate the license plate. The light guide is arranged on the display surface side of the license plate such that the side surface on which the light emitting surface is formed is along the outer edge of the license plate. Note that a light guide may be installed at a certain distance from the display surface of the license plate so that the light from the light emitting surface can illuminate a wide area of the license plate with more uniform illuminance. Preferably, the light guide may be in contact with the license plate, or the light guide may be arranged close to the license plate.
[0015]
A rod-shaped or frame-shaped light guide is used. When a rod-shaped light guide is used, a part of the side surface becomes a light emitting surface, and linear or planar light can be obtained. Therefore, in this case, if one light guide is used, the display surface of the license plate is illuminated by linear or planar light from one direction. For example, if such a light guide is installed along the top, bottom, right or left edge of the license plate, the license plate is illuminated from above, below, right or left, respectively. You. On the other hand, it is possible to illuminate the license plate from multiple directions by using a plurality of light guides. For example, if a bar-shaped light guide is installed along the upper edge and the lower edge of the license plate, the upper and lower light guides can be illuminated. The license plate is illuminated by light from below.
When a frame-shaped light guide is used, the license plate can be illuminated with light from four directions, up, down, left, and right.
[0016]
A reflecting surface is formed on a part of the light guide, and the traveling direction of the introduced light can be changed by the reflecting surface. For example, a reflection surface is formed at the end of the light guide, and the light source is arranged such that the introduced light is reflected by the reflection surface to be converted into light in the longitudinal axis direction of the light guide (for example, The light source is arranged to face the end side surface of the light guide). The use of such a reflective surface increases the degree of freedom in arranging the light source, which is advantageous in design (for example, it is easy to adopt a light source position suitable for an installation target).
[0017]
It is preferable that surfaces other than the light introduction surface and the light emission surface of the light guide are covered with a light-reflective material. That is, it is preferable that the light reflecting layer is formed on the surface. This is for preventing light from leaking from the surface to efficiently emit light from the light emitting surface. In addition, if a light reflecting layer is provided, not only light reflection but also light diffusion is carried out, so that light diffusion in the light guide can be promoted, so that light with more uniform illuminance can be emitted from the light emitting surface. can do.
[0018]
An uneven portion can be formed on a part of the light guide surface (for example, a light emitting surface). The irregularities reflect the light of the light source introduced into the light guide, and can promote irregular reflection and diffusion of light in the light guide. The unevenness here includes a groove shape such as a triangular groove, a square groove, a round groove, and a pit shape. A plurality of irregularities having different shapes may be used in combination. Such irregularities can be formed continuously, or they can be formed discontinuously, such as in a dot shape. Further, they may be formed regularly or randomly.
Such an uneven portion can be formed by shaving a part of the surface of the light guide using a needle-shaped or saw-tooth-shaped processing tool, or by performing a cutting process, a polishing process, or the like on the surface of the light guide. it can. Alternatively, such a concavo-convex portion can be formed by producing the light guide by molding using a mold that forms a desired concavo-convex portion.
[0019]
The material of the light guide is not particularly limited as long as it is transparent to light from the light source. Preferably, the light guide is made of a transparent (including colorless and colored transparent) material. It is preferable that the light guide is made of a material that is easy to process and has excellent durability. As a material of the light guide, for example, acrylic resin, polyethylene terephthalate (PET), polycarbonate resin, epoxy resin, glass, or the like can be used.
[0020]
A light source is arranged inside the light guide or outside the light guide. In the former case, for example, a space for accommodating the light source is provided in a part of the light guide. For example, a space (groove) for accommodating the light source can be provided at the end of the light guide. In such a configuration, since the light source and the light guide are integrally formed, the sealing performance is improved, and a lighting device having a high dustproof and waterproof effect is obtained. In addition, good light guiding efficiency and reduction in the number of assembly steps can be expected. On the other hand, according to the configuration in which the light source is disposed outside the light guide, that is, the configuration in which the light source is separate from the light guide, the degree of freedom in designing the light source and the light guide is increased, and both can be made compact. Also, the configuration of the entire lighting device is simplified. Furthermore, a sufficient waterproof / dustproof effect can be obtained for the light source section even with a simple structure.
[0021]
A surface that tapers toward the light emitting surface as the distance from the light source increases can be formed on the side of the light guide opposite to the light emitting surface. The entire side surface of the light guide may be such a tapered surface. For example, when the light source is arranged to face the end face of the light guide, the side surface of the light guide may be a surface that tapers from the end face facing the light source to another end face. In the case where such a tapered surface is formed, for example, if light from a light source is introduced such that its optical axis is parallel to the light emitting surface of the light guide, the introduced light is efficiently reflected and diffused by the tapered surface. Thereby, the light density distribution in the light guide is made more uniform.
[0022]
The lighting device of the present invention is used by being attached to a rear part of a vehicle body such as a license plate or a bumper or a trunk grid on which the license plate is installed.
Hereinafter, the configuration of the present invention will be described in more detail using examples.
[0023]
【Example】
FIG. 1 is a perspective view showing a license plate lighting device 1 (hereinafter, referred to as a “lighting device 1”) according to an embodiment of the present invention. FIG. 2 is an enlarged perspective view showing a part of the light guide 10 used in the lighting device 1. FIG. 3 is a sectional view taken along line AA in FIG.
The lighting device 1 is schematically composed of a light guide 10, two light emitting diodes 20 and 21, and a design cover 30. The light guide 10 is a member formed by molding an acrylic resin material into a rod shape. In this embodiment, a light guide 10 having a rectangular cross section is used. When the license plate 100 is installed, the light guide 10 is positioned obliquely above the license plate 100, and its longitudinal axis is parallel to the upper edge of the license plate 100. The LEDs 20 and 21 face the end faces 11 and 12 of the light guide 10, respectively. That is, both end surfaces of the light guide 10 become light introduction surfaces. A layer (light reflecting layer) made of a light reflecting material is formed on the surface (14, 15, and 16) of the side surface of the light guide 10 other than the surface (ie, the lower surface) facing the license plate 100. By providing the light reflecting layer in this manner, light is prevented from leaking from the surfaces 14, 15 and 16 on which the light reflecting layer is formed, while the lower surface where the light reflecting layer is not formed is the light emitting surface 13 As a result, efficient light emission is performed from there. The light reflecting layer can be formed by, for example, a paint or ink having a white or metallic luster.
Instead of or in addition to the light reflecting layer, the side surface of the light guide 10 may be subjected to light diffusion processing (graining, engraving, etc.).
[0024]
The LEDs 20 and 21 are both bullet-type and white-emitting LEDs. A current is supplied to these LEDs 20 and 21 via wiring (not shown). In order to achieve efficient light introduction into the light guide 10, the LEDs 20 and 21 are arranged in close proximity to the opposing light guide end faces (light introduction surfaces) 10 and 11, respectively.
[0025]
The design cover 30 is a resin member having a U-shaped cross section with an open bottom. The surface of the design cover 30 may be subjected to plating or painting (for example, the same color as the body of the vehicle to be installed). Further, the design cover 30 can be manufactured using a metal material. For example, the design cover 30 may be formed by processing a metal plate into a predetermined shape and then performing surface painting.
[0026]
When the license plate 100 is mounted, first, the lighting device 1 is installed and fixed to a vehicle body 70 such as a bumper or a trunk lid, and then the license plate 100 is fixed to a predetermined position using a screw 50 (FIG. 3). See).
[0027]
Next, the lighting mode of the lighting device 1 will be described. First, an electric current is supplied to each of the LEDs 20 and 21 in conjunction with the lighting of the vehicle width lamp (small lamp), and white light is emitted from each of the LEDs 20 and 21. This white light is introduced into the light guide 10 from the end faces 11 and 12 of the light guide 10, respectively. The guided light is reflected and diffused by the light reflecting layers formed on the surfaces of the light guide side surfaces 14, 15 and 16 in the process of guiding the light guide 10. As a result, light in the direction of the light emitting surface 13 is generated, and light is finally emitted through the light emitting surface 13. In addition, the diffusion of light in the light guide 10 is promoted by the function of the light reflection layer, and the light density in the light guide 10 is made uniform. As a result, planar light 18 having uniform illuminance is emitted from the light emitting surface 13. Then, as shown in FIG. 3, almost the entire display surface of the license plate 100 is illuminated by the planar light, and the visibility is effectively enhanced.
[0028]
FIG. 4 shows a license plate lighting device 2 (hereinafter, referred to as “lighting device 2”) according to another embodiment of the present invention. FIG. 5 is a cross-sectional view taken along the line BB in FIG. 4 and schematically illustrates the mounting mode and the lighting mode of the lighting device 2. In each drawing, the same members as those of the license plate lighting device 1 described above are denoted by the same reference numerals, and description thereof will be omitted.
In the illumination device 2, a pair of light source units 2a and 2b are used. Each of the light source units 2a and 2b corresponds to the license plate lighting device 1, and is installed so as to sandwich the license plate 100 from above and below. Then, as shown in FIG. 5, the light 19a and 19b emitted from each of the light source units 2a and 2b illuminate the display surface of the license plate 100. By illuminating the license plate 100 from above and below, higher illuminance can be obtained. In addition, uneven illuminance in the vertical direction is reduced. As described above, the illumination device 2 illuminates with high illuminance and light with low illuminance unevenness, and the visibility of the license plate 100 becomes extremely good.
[0029]
In the lighting device 2, the license plate 100 is illuminated from the upper and lower directions. As shown in FIG. 6, the license plate 100 is illuminated using the light source units 3a and 3b (the lighting device 3) arranged on both sides of the license plate 100. It can also be illuminated from two directions. By illuminating from two directions in the left and right directions as described above, higher illuminance can be obtained as in the case of using the illumination device 2 and illuminance unevenness in the left and right directions can be reduced. The light source units 3a and 3b used in this example are different from the light source units 2a and 3b used in the lighting device 2 except that the length of the light guide 17 incorporated therein and the size of the design cover 35 are different. This is the same configuration as 2b.
[0030]
Next, still another embodiment of the present invention will be described with reference to FIGS. FIG. 7 is a perspective view showing a license plate illuminating device 4 (hereinafter, referred to as “illuminating device 4”) of this embodiment, and FIG. 8 is an enlarged view of a part of a light guide 40 used in the illuminating device 4. FIG. In the illumination device 4, a light guide 40 having reflection surfaces 41 and 42 formed at each end thereof is used. Hereinafter, the configuration of the light guide 40 will be described by taking an end on the side where the reflection surface 41 is formed as an example (see FIG. 8). The reflection surface 41 forms a predetermined interior angle α with the light guide side surface 46 facing the light source. In the light guide 40 of this embodiment, α is set to 45 °. However, the angle is not limited to α, and an appropriate angle can be set as appropriate within a range where the introduced light can be efficiently reflected. A light-reflective layer made of a white material is formed on the surface of the reflection surface 41 in order to increase the reflection efficiency.
Light emitted from the LED 20 is introduced into the light guide 40 through a partial area (approximate area is indicated by oblique lines) of the light guide side surface 46. Most of the introduced light 25 reaches the reflection surface 41 and is reflected and converted into light 26 in the longitudinal direction of the light guide. As described above, in the illumination device 4, the light guide action in the longitudinal direction of the light guide is generated by the reflection surface 41 formed at the end, and the same illumination mode as the illumination device 1 is obtained. In addition, a light reflection layer is formed on the surface of the side surfaces 44 and 45 and the side surface 46 of the light guide 10 which is not involved in the introduction of light, so as to prevent light leakage from the portion and to diffuse light. By promoting the light emission, light emission with less illuminance unevenness from the light emission surface 43 is enabled.
[0031]
In the above-described license plate lighting devices 1 to 4, LEDs are used as light sources, but bulbs, cold cathode tubes, and the like can be used instead.
[0032]
In the lighting devices of the above embodiments, a light guide having a rectangular cross section is used. For example, a light guide 60 having a semicircular cross section as shown in FIG. 9 may be used. In such a light guide body 60, the curved surface portion becomes the light emitting surface 63, and a light refracting action corresponding to the curved surface shape occurs at the time of light emission. By utilizing such an operation, it is possible to control the mode of light emitted from the light guide 60. It is to be noted that the entire curved surface portion may not be the light emitting surface, but may be only a part of the light emitting surface (for example, a light reflecting layer may be formed on a part of the curved surface portion, and light may be emitted from the portion. Not to be).
[0033]
On the other hand, various configurations can be adopted for the shape of the side surface other than the light emitting surface of the light guide. An example is shown in FIG. In the example shown in FIG. 10A, the upper surface 81 of the light guide is tapered so as to continuously approach the lower surface (light emitting surface) 83 from the end of the light guide toward the center. With such a tapered surface, the received light can be efficiently converted into light in the direction of the light emitting surface 83, so that the illuminance of external radiated light can be improved. In the upper surface 81, a region farther from the light source disposed to face the end surfaces 85 and 86 is closer to the optical axis of the light source, so that more efficient light reception and reflection can be performed. As a result, the illuminance of the light emitted from the light emitting surface 83 is further uniformed. In this example, the upper surface 81 is a flat surface, but may be a curved surface 81a as shown in FIG. The same effect as in the case of (a) can be expected in the light guide having such a configuration.
On the other hand, FIGS. 10C and 10D show examples of a light guide whose upper surface is processed in a stepped manner. First, in the light guide (c), inclined surfaces approaching the lower surface (light emitting surface) 83 from the end of the light guide toward the center are formed at predetermined intervals on the upper surface 81b. By providing such an inclined surface, the illuminance can be improved and the illuminance can be made uniform, as in the example of (a).
In the example of (d), the inclined surfaces are formed at predetermined intervals on the upper surface 81c as in the case of (c), but a curved surface is employed as the shape of each inclined surface. By adopting such a curved inclined surface, it is easy to secure a light incident angle sufficient to cause efficient reflection of light received by each inclined surface. As a result, improvement in light use efficiency, that is, improvement in illuminance of illumination light can be expected. Further, it is expected that the light density distribution in the light guide can be made more uniform because light is reflected in a curved surface to generate light in multiple directions.
[0034]
The present invention is not limited to the description of the embodiment of the present invention at all. Various modifications are included in the present invention without departing from the scope of the claims and within the scope of those skilled in the art.
[0035]
【The invention's effect】
In the lighting device of the present invention, the light from the light source is converted into linear or planar light by the light guide, and light capable of illuminating a wide area with little illuminance unevenness is obtained. Therefore, it is possible to effectively increase the visibility of the numbers and the like displayed on the license plate. In addition, by using a rod-shaped or frame-shaped light guide, the amount of light guide used can be reduced, and the lighting device can be reduced in weight and the manufacturing cost can be reduced.
[Brief description of the drawings]
FIG. 1 is a perspective view showing a license plate lighting device 1 according to one embodiment of the present invention.
FIG. 2 is a partially enlarged view of a light guide 10 used in the license plate lighting device 1.
FIG. 3 is a sectional view taken along line AA of FIG. 1;
FIG. 4 is a perspective view showing a license plate lighting device 2 according to another embodiment.
FIG. 5 is a sectional view taken along line BB of FIG. 4;
FIG. 6 is a perspective view showing a license plate lighting device 3 according to another embodiment.
FIG. 7 is a perspective view showing a license plate lighting device 4 according to another embodiment.
FIG. 8 is a partially enlarged view of a light guide 40 used in the license plate lighting device 4.
FIG. 9 is a perspective view showing an example of a light guide 60 that can be used in the present invention.
FIG. 10 is a sectional view showing another example of a light guide usable in the present invention.
[Explanation of symbols]
1 2 3 4 License plate lighting device 10 17 40 60 Light guide 11 12 Light introduction surface 13 43 63 Light emission surface 20 21 White LED
30 35 Design cover 41 42 Reflective surface 100 License plate

Claims (8)

A light source, and a rod-shaped or frame-shaped light guide that introduces the light of the light source and externally radiates the introduced light through a part of the side surface, such that a part of the side surface is along an outer edge of the license plate. And a light guide disposed on the display surface side of the license plate. 2. The license plate lighting device according to claim 1, wherein the light guide has a rod shape, and a longitudinal axis thereof is installed along an upper edge or a lower edge of the license plate. 3. Two said light guides are used, one light guide is rod-shaped and its longitudinal axis is arranged along the upper edge of the license plate, and the other light guide is rod-shaped and its longitudinal axis is The license plate lighting device according to claim 1, wherein the license plate illumination device is installed along a lower edge of the license plate. Two said light guides are used, one light guide is rod-shaped and its longitudinal axis is arranged along the left edge of the license plate, the other light guide is rod-shaped and its longitudinal axis is The license plate lighting device according to claim 1, wherein the license plate lighting device is installed along a right edge of the license plate. The license plate lighting device according to claim 1, wherein the light source is arranged to face an end surface of the light guide. A reflection surface is formed at an end of the light guide,
The light source is arranged to face an end side surface of the light guide so that light introduced from the light source is converted into light in a longitudinal axis direction of the light guide by being reflected by the reflection surface. The license plate lighting device according to claim 1, wherein: The license according to any one of claims 1 to 6, wherein a surface of the light guide other than a region for introducing light of the light source and a region for externally radiating the introduced light is covered with a light-reflective material. Plate lighting device. The license plate lighting device according to claim 1, wherein the light source comprises an LED.

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