JP2003237463A - Lighting system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lighting system for a number plate capable of constituting a number plate part into a thin (compact) type with simple constitution, to provide a versatile lighting system applicable to a general number plate, and to provide a lighting system capable of enhancing effectively visibility for a number plate. <P>SOLUTION: This lighting system is provided with a light source, and a light guide panel arranged in a front face side of the number plate, to which light of the light source is introduced, and for emitting the introduced light from a side surface of the number plate. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to improvement of a license plate portion of a vehicle. Specifically, it relates to a lighting device for a license plate.

[0002]

2. Description of the Related Art As a method of improving the visibility of a license plate of an automobile, a method of irradiating the license plate surface with the light of a valve installed above or below the license plate, and a method of using a letter-light type license plate Is used. Various improvements have been proposed for the letter-light type license plate (see, for example, Patent Documents 1 to 3). Also, see Patent Documents 4 and 5 as technologies related to the present invention.

[0003]

[Patent Document 1] JP-A-10-129344

[Patent Document 2] Japanese Patent Laid-Open No. 2000-313279

[Patent Document 3] Japanese Patent Laid-Open No. 10-119669

[Patent Document 4] US Pat. No. 5,934,798

[Patent Document 5] US Pat. No. 6,471,379

[0004]

Since the light of the bulb used in the former method has a low directivity, even if the bulb is installed so as to face the license plate, some of the light emitted from the bulb will not be reflected by the number. Head in a direction other than the plate. Such light is not used for illuminating the license plate, but rather becomes a hindrance when checking the license plate and becomes a factor that reduces the visibility of the license plate. In addition, the design of the license plate portion is deteriorated. From a design point of view, it is not preferable that the valve itself is observed from the outside. Considering the above, the valve periphery other than the license plate side was covered with garnish. On the other hand, it is necessary to incline the license plate obliquely with respect to the mounting surface so that the light from the bulb can be easily irradiated onto the surface. As described above, in the conventional method, it is necessary to cover the periphery of the light source with the garnish and to provide the license plate with an inclination, and as a result, the license plate portion must be thick in the entire length direction of the vehicle.

On the other hand, even in the case of the light-lit type license plate, it is necessary to secure a space for arranging the backlight on the back surface side of the license plate, which is a thick device as a whole. In addition, since it is necessary to use a specially processed license plate, a general license plate cannot be used, and the versatility is poor. In addition, the structure is complicated and the manufacturing cost is high. The present invention has been made in view of the above problems, and an object of the present invention is to provide an illuminating device for a license plate with a simple structure in which the license plate portion can be made thin (compact). Also,
It is an object of the present invention to provide a highly versatile lighting device that can be applied to general license plates. Furthermore, it aims at providing the illuminating device which can improve the visibility of a license plate effectively.

[0006]

The present invention has the following constitution in order to achieve at least one of the above objects. That is, the illumination device includes a light source and a light guide plate arranged on the front side of the license plate, the light guide plate introducing the light from the light source and radiating the introduced light from the license plate side surface.

In the illuminating device constructed as described above, first, the light emitted from the light source is introduced into the light guide plate, and then the introduced light is emitted from the license plate side surface of the light guide plate. Then, the emitted light irradiates the license plate surface to enhance the visibility of characters and numbers on the license plate surface. In addition, the light guide plate is placed on the front side of the license plate, and the light emitted from the surface of the light guide plate is used to illuminate the license plate surface. There is no need to tilt the license plate. Therefore, it is possible to prevent the license plate portion from becoming thicker as the license plate is inclined, that is, the license plate portion can be made thinner.
The fact that the license plate part can be made compact or thin also has the effect of increasing the degree of freedom in designing the license plate part.

Further, the illuminating device of the present invention can be applied to a general license plate, that is, a special license plate such as a conventional letter-light type is not required.
The versatility is high and the configuration is simple. Further, the light from the light source is converted into planar light through the light guide plate, and the planar light is used to illuminate the surface of the license plate, so that illumination with a high illumination effect is performed. This also means that it is possible to construct a license plate portion having a high design. Therefore, according to the illuminating device of the present invention, it is possible to configure a license plate portion having high visibility and excellent designability. Hereinafter, each member of the present invention will be described.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION (Light Source) As a light source, an LED,
A light bulb (bulb), a fluorescent lamp, a cold cathode tube, etc. can be used. Above all, it is preferable to adopt the LED. LE
Since the D light source consumes less power and generates less heat and has a long life, it is a light source suitable for continuous lighting for a long time. Further, since the size is small, the space for the light source is small, and the license plate portion can be downsized and thinned. As a result, there is also a secondary effect that the degree of freedom in designing the license plate portion is improved. At the same time, the handleability of the lighting device is also improved. Further, since the LED is strong against vibration and shock, there is an advantage that a highly reliable lighting device can be configured. The type of LED is not particularly limited, and various types such as a bullet type and a chip type can be adopted.

The light emission color of the light source adopted is not particularly limited, either.
A light source that emits light in the 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 adopted, the numbers and the like displayed on the license plate and the background can be observed (visually recognized) in the original color. 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 or the design can be improved, for example, by adding color to the license plate background on a white background.

It is also possible to use a light source that emits light in the ultraviolet region. In this case, a phosphor that receives fluorescence in the ultraviolet region and fluoresces can be used together. A light source capable of emitting light in the visible region and the ultraviolet region may be used. For example, a layer containing a phosphor can be provided on the surface of a light guide plate described later (the surface on which light from a light source is introduced, the surface on the license plate side, etc.). Such a layer containing the phosphor can be formed by printing or coating ink or paint containing the phosphor, or by sticking a sheet containing the phosphor. Further, the phosphor can be contained in the light guide plate described later. With such a configuration, fluorescence is generated in the light guide plate, and the license plate is illuminated by radiating the fluorescence from the surface of the light guide plate. When the phosphor is contained in the light guide plate, 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. On the other hand, the phosphor may be contained in the license plate to which the lighting device of the present invention is applied. For example, it is possible to form a display portion (characters, numbers) of the license plate using a paint or ink containing a phosphor, or to separately provide a layer containing a phosphor 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 surface via the light guide plate to excite the phosphor of the display unit. As a result, the display section is luminescently displayed by fluorescence.

The type of phosphor is not particularly limited, and may be an organic type,
Any inorganic type can be adopted. By using an organic fluorescent substance, it is possible to obtain a clear fluorescent light. On the other hand, when an inorganic phosphor is used, it is possible to obtain fluorescent light having a matt feeling. Phosphors having various fluorescent colors can be adopted. For example, in addition to phosphors having fluorescent colors of red, green, or blue which are the three primary colors of light, phosphors that emit intermediate colors thereof can be used. . A plurality of phosphors may be used in combination, and for example, a red phosphor, a green phosphor, and a blue phosphor may be mixed and used.

The light source of the present invention may be constructed using a plurality of LEDs, bulbs and the like. In this case, it is possible to use a plurality of light sources of the same kind or to use light sources of different emission colors in combination. By using a plurality of light sources, it is possible to obtain effects such as enhancement of illuminance or illumination of various emission colors by color mixing 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 plate, the required illuminance, and the like. As an example using a plurality of light sources, for example, a red LED, a green LED
White light can be obtained using three types of ED and blue LEDs. In this case, by controlling the light emitting state and light emitting amount of each LED, it is possible to obtain light of a desired color.

The light source is arranged at a position where light can be introduced into the light guide plate described later. It is preferable to arrange the light source so as to face the end surface of the light guide plate. With this configuration, the introduced light is well guided in the light guide plate, and as a result, it is possible to irradiate the light from a wider range of the light guide plate surface (light emitting surface) on the license plate side, and the uneven illuminance Light can be emitted in a smaller amount. For example, the upper end surface, the lower end surface, the left end surface of the light guide plate,
And / or one or more light sources may be arranged to face the right end face. Above all, it is preferable to dispose the light source so as to face the upper end surface of the light guide plate. That is, it is preferable to irradiate from above the light guide plate toward the lower end. When the observation surface of the light guide plate is subjected to a light diffusion treatment as described below, for example, if light from the light source is introduced from the lower end surface of the light guide plate, a large amount of light obliquely upward from the back surface side enters the observation surface. Most of the light emitted from the surface to the outside is obliquely upward or upward. Here, since the viewpoint of the observer (for example, the driver of another vehicle) is normally located obliquely upward when viewed from the illumination device, a large amount of light travels toward the viewpoint of the observer, resulting in the license plate. The observation surface of the light guide plate emits light and is observed, and the license plate becomes difficult to see. On the other hand, if the light source is arranged above the light guide plate and the light is introduced from the upper end of the light guide plate, most of the light emitted from the observation surface of the light guide plate is light directed obliquely downward or downward, that is, the viewpoint of the observer. A small amount of light travels in the direction, and as a result, the phenomenon that the observation surface of the light guide plate emits light and the license plate becomes difficult to see is prevented. The same effect can be obtained when the light source is arranged at the side of the light guide plate (either the left or right end portion, or the left and right end portions), but when it is arranged above the light source, it is closer to the observer's viewpoint. Since the amount of emitted light is small, it can be said that the position above the light guide plate is most suitable as the position of the light source. Here, as a specific example of the arrangement mode of the light source, there may be mentioned an aspect in which a plurality of LEDs are linearly arranged in a state of facing one end surface (preferably the upper end surface) of the light guide plate. In such a mode, there is also an advantage that the configuration of the circuit used for lighting each LED can be simplified.

Here, when the light amount of the light source is not sufficient,
In the case where a good light guiding action cannot be obtained, there is a possibility that the light distribution in the light guiding plate may be uneven. For example, the amount of light decreases in a region away from the light source, and as a result, illuminance unevenness may occur in the light emitted from the surface of the light guide plate.
In such a case, it is preferable to arrange the light sources so that light is introduced from the upper and lower sides or the left and right ends of the light guide plate. For example, a row of LEDs is arranged facing the upper end surface of the light guide plate, and a row of LEDs is similarly arranged facing the lower end surface of the light guide plate.
To place. Alternatively, one row of LEDs is used so as to face the left end surface and the right end surface of the light guide plate, respectively. The LEDs may be arranged in four directions so as to face the upper, lower, left, and right end surfaces. Further, the LEDs can be arranged on three sides of the left and right end faces and the upper end face, or the left and right end faces and the lower end face. From the viewpoint of light introduction efficiency and compactness of the device, it is preferable to dispose the light source close to the light guide plate.

(Light Guide Plate) The light guide plate is a member which is composed of a plate-shaped light guide and is arranged on the front side of the license plate. A light guide plate having a plan view area that can cover the entire display surface of the license plate is used. In order to make the lighting device compact, it is preferable to use a light guide plate whose plan view shape is substantially the same as or slightly larger than that of the license plate. In addition, it is preferable to use the thinnest light guide plate as long as the effect of the light guide plate of introducing the light from the light source and irradiating the introduced light to the license plate surface can be sufficiently obtained. For example, 1 mm
A 15 mm thick light guide plate can be used. If it is thinner than this, sufficient mechanical strength cannot be obtained, which is not preferable. Further, if the thickness is thicker than this, the number plate portion becomes thick, which is not preferable, and it is also not preferable because the manufacturing cost increases. Preferably from 2 mm
A light guide plate having a thickness of 10 mm, more preferably 3 mm to 5 mm is used.

When the illumination device of the present invention is used (mounted on the license plate portion), it is preferable that the light guide plate is close to the license plate. This is because the license plate portion can be made thinner. For example, it is preferable to configure the lighting device so that the light guide plate is in close contact with the license plate when in use. However, it is also possible to use a light guide plate in which a space is formed between the light guide plate and the license plate during use. By adopting a configuration in which the seal of the license plate is housed inside such a light guide plate, it is not necessary to seal the seal portion, and the light guide plate can be opened and closed without removing the seal. In addition, a layer or the like for promoting diffusion of light may be interposed between the light guide plate and the license plate. For example,
A light guide plate in which a layer containing a light diffusing material is formed on the surface facing the license plate can be used. A layer containing such a light diffusing material is used for attaching a sheet in which the light diffusing material is dispersed,
It can be formed by applying a resin containing a light diffusing material.

A concavo-convex portion is formed on the license plate side surface of the light guide plate (also referred to as "light emitting surface" in this specification) or the surface opposite to the license plate side (also referred to as "observation surface" in this specification). Preferably. It is also possible to form uneven portions on both sides. The irregularities can reflect the light of the light source introduced into the light guide plate and promote diffuse reflection and diffusion of the light in the light guide plate. Thereby, the introduced light can be efficiently radiated to the outside from the surface of the light guide plate on the license plate side, and thus the license plate surface can be efficiently illuminated. Further, it is possible to radiate planar light with little unevenness of luminous intensity from the surface of the light guide plate on the license plate side, so that the illumination effect is improved and the design of the license plate portion is improved.

The irregularities herein include groove shapes such as triangular grooves, square grooves, and round grooves, and pit shapes. You may use combining the unevenness of different shape in multiple numbers. Such unevenness can be formed continuously, or can be formed discontinuously such as dots. Further, it may be formed regularly or randomly. Such an uneven portion can be formed by cutting off a part of the surface of the light guide plate using a needle-shaped or saw-tooth-shaped processing tool, or by subjecting the surface of the light guide plate to a cutting process or a polishing process. . Alternatively, such a concavo-convex portion can be formed also by producing the light guide plate by molding using a mold in which a desired concavo-convex portion is formed.

Preferably, the uneven portion as described above is provided on the observation surface of the light guide plate. With this configuration, the light introduced into the light guide plate can be diffusely reflected and diffused on the observation surface and efficiently emitted from the light emitting surface of the light guide plate. Therefore, the license plate surface can be efficiently illuminated.
Since the observation surface of the light guide plate is a surface that is directly observed from the outside, when an uneven portion is provided on the observation surface, the shape and size are such that the unevenness is visually recognized and the designability of the license plate is not deteriorated. It is preferable to employ irregularities such as. It is preferable to provide the uneven portion as described above on the entire observation surface of the light guide plate so that the light is emitted from the light emission surface in a state where the light emission is more uniform. Further, it is preferable to form the unevenness on the surface of the light guide plate such that the density of the unevenness becomes higher in the region farther from the surface where the light of the light source is introduced. In this way, more efficient diffuse reflection and diffusion of light occur in the area where the amount of light reaching the surface decreases, and as a result, uneven emission of light emitted from the light emitting surface is further reduced. It It should be noted that such a change in the uneven density may be continuous or stepwise. When a light guide plate having a larger shape in plan view than the license plate is used, a part (for example, an edge) of the light guide plate may have a region where no unevenness is formed.

On the observation surface of the light guide plate, it is possible to form a surface that tapers toward the license plate side as the distance from the light source increases. The entire surface of the light guide plate may be formed with such a tapered surface. For example, when the LED light source is arranged to face the upper end surface of the light guide plate, the surface of the light guide plate may be a surface that tapers from the upper end surface toward the lower end surface. When such a tapered surface is provided, for example, if the light of the LED light source is introduced from the upper end surface of the light guide plate with its optical axis parallel to the light emitting surface of the light guide plate, the introduced light is guided by the tapered surface. The light can be reflected in the light emitting surface direction. Thereby, the radiation efficiency of the light from the light emitting surface of the light guide plate is increased, and the license plate can be efficiently illuminated.

A cover may be provided to cover the light source and the end surface and edge of the light guide plate. This cover is provided for the purpose of preventing the light source from being observed from the outside, preventing light from leaking from the end surface and the edge portion of the light guide plate, and protecting the edge portion of the light guide plate. .

Depending on how the end face of the light guide plate is processed,
In some cases, the light that escapes can be almost ignored. Also, depending on the viewpoint, observing light from the end surface (and / or edge portion) of the light guide plate has a decorative effect. Further, the end surface (and / or the edge portion) of the light guide plate may be subjected to a cutting process or the like to create a light emitting mode in which a more decorative effect is obtained. That is, it is possible to positively emit light from the end surface (and / or edge portion) of the light guide plate and use this for decoration of the license plate portion. Thus, depending on the design of the light guide plate, it may not be necessary to hide the end surface of the light guide plate, or it may be preferable to leave the end face exposed. So in such cases,
Instead of the cover as described above, a cover that covers only the light source, a cover that covers only a part of the light source and the end surface (for example, the upper end surface), a light source, a part of the end surface (for example, the upper end surface), and an edge continuous with the cover. A cover or the like that covers only the portion can be used.

The material of the light guide plate is not particularly limited as long as it is transparent to the light of the light source. Preferably, the light guide plate is made of a transparent material (including colorless and transparent and colored and transparent).
Further, it is preferable that the light guide plate is made of a material that is easy to process and has excellent durability. As the material of the light guide plate, for example, polycarbonate resin, acrylic resin, epoxy resin, glass or the like can be used.

A light source is arranged inside or outside the light guide plate. In the former case, for example, a space for accommodating the light source is provided in a part of the light guide plate. For example, a groove for accommodating a light source can be provided on the end surface (upper end surface, lower end surface, or left and right end surfaces) of the light guide plate. In such a configuration in which the light guide plate has a space for accommodating the light source, the light source and the light guide plate are integrally formed, so that the sealing performance is improved, and the lighting device has a high dustproof and waterproof effect. In addition, good light guiding efficiency and reduction in assembly man-hours can be expected. On the other hand, since it becomes necessary to design the light guide plate in consideration of waterproofing measures for the light source unit, the structure of the light guide plate becomes complicated. On the other hand, if the light source is arranged outside the light guide plate, that is, if the light source part is separate from the light guide plate, the degree of freedom in designing the light source part and the light guide plate is increased, and both can be made compact. Also, the configuration of the entire lighting device is simplified. Further, with respect to the light source section, a sufficient waterproof / dustproof effect can be obtained even with a simple structure.
In addition, at the time of use, the light source unit is fixed to the vehicle side,
It is possible to adopt a configuration in which the license plate can be attached by sliding, opening and closing the light guide plate. With such a configuration, the light source unit does not move during the work of attaching or detaching the license plate, the risk of damaging the light source unit during the work is reduced, and the wiring to the light source unit is easy and simple. And a further simplification of the overall structure of the lighting device is achieved.

(Seal member) A state in which the lighting device of the present invention is attached to a vehicle and a license plate is attached (at the time of use)
In, it is preferable to provide a member for sealing the inside of the lighting device (that is, the space where the license plate is installed).
This is to impart waterproofness and dustproofness and to secure high visibility of the license plate for a long period of time. As such a seal member, one that directly seals between the edge portion of the light guide plate and the vehicle body can be adopted. In such a configuration, the light guide plate is directly connected to the vehicle body via the seal member. Therefore, the support plate (base frame) used for installing and fixing the lighting device can be omitted,
As a result, a reduction in the number of parts and a consequent reduction in weight and manufacturing cost are achieved. The seal member may be made of a known material such as silicone rubber. As the shape of the seal member, a shape used for normal sealing such as a rib shape can be adopted.

The lighting device of the present invention comprises a license plate,
Alternatively, it is used by being attached to the rear part of the vehicle body such as a bumper or a trunk lid where a license plate is installed. The lighting device of the present invention can be configured integrally with the license plate. In this case, the lighting device of the present invention incorporating the license plate is attached to a bumper, a trunk grid or the like.

[0028]

EXAMPLES The constitution of the present invention will be described in more detail with reference to examples. FIG. 1 is a perspective view showing a license plate illuminating device 1 (hereinafter referred to as “illuminating device 1”) which is an embodiment of the present invention. FIG. 2 is a sectional view taken along the line AA of FIG. Further, FIG. 3 is a cross-sectional view showing a mounting mode of the lighting device 1. The illumination device 1 is roughly configured by a light guide plate 10, a plurality of LEDs 20 arranged on a substrate 25, a support plate 30, and a casing 40. The light guide plate 10 is made of an acrylic resin material and is a flat plate member having a thickness of about 4 mm.
The plan view shape is substantially the same as the license plate 100.
It should be noted that the license plate 100 is not exclusively used for the lighting device 1 but is widely and generally used. Surface of light guide plate opposite to license plate 100 (observation surface)
A large number of grooves 12 each having a substantially triangular shape and extending in a dotted line in the vertical direction are formed so as to be staggered in the horizontal direction. The innumerable grooves are formed more densely in a region farther from the upper end surface 13. Specifically, in the region closest to the upper end surface 13 side, grooves having a length of about 1.77 mm, a width of about 0.22 mm, and a depth of about 0.1 mm are formed at a pitch of about 0.5 mm in the vertical direction. ing. The lateral pitch of the grooves is about 1.47 mm. On the other hand, in the vicinity of the center of the light guide plate 10, the pitch is about 0.49 mm in the vertical direction, the length is about 1.62 mm, the width is about 0.21 mm, and the depth is about 0.08 mm.
Grooves are formed. The lateral pitch of the groove is about 1.1.
It is 6 mm. In the region farthest from the upper end surface 13, the pitch is about 0.27 mm in the vertical direction and the length is about 1.2.
A groove having a size of 6 mm, a width of about 0.22 mm and a depth of about 0.06 mm is formed. Horizontal groove pitch is approximately 0.36 mm
Is. Such a groove can be formed by treating the light guide plate observation surface 12 so as to scratch it with a processing tool having an infinite number of metal needles on the surface. The surface (light emitting surface) 11 of the light guide plate on the license plate 100 side is a mirror surface.

The LEDs 20 are mounted in a line on the substrate 25. Then, the board 25 is fixed at a predetermined position of the casing 40 described later, so that each LE
D20 are arranged in a row so as to face the upper end surface 13 of the light guide plate 10. Further, each LED 20 is arranged at a position close to the upper end surface 13 of the light guide plate 10 so that the light of the LED 20 is efficiently introduced into the light guide plate 10.

On the substrate 25, a protection resistor is mounted in addition to the LEDs 20, and a wiring pattern for connecting the LEDs 20 in series is formed. In addition, each LE
The D20 may be connected in parallel. In this embodiment, a total of 16 cannonball type, white light emitting LEDs 20 are used. A current is supplied to the LED 20 via a wire (not shown).

The support plate 30 is a member provided to fix the position of the license plate 100. As shown in FIG. 2, the license plate 100 includes the support plate 30.
And the light guide plate 10. When the license plate 100 is attached to the vehicle body, the screw 50
And 51 are used (see FIGS. 1 and 3), and the position of the license plate 100 is fixed by being sandwiched between the light guide plate 10 and the support plate 30. The support plate 30 may be provided integrally with the casing 40 described below.

A frame-shaped casing 40 for accommodating the light guide plate 10 and the LEDs 20 is used. Casing 40
Is a frame member made of resin. The surface may be plated (for example, the same color as the vehicle body to be installed). The casing 40 can also be manufactured using a metal material. For example, the casing 40 may be formed by processing a metal plate into a frame shape and painting the surface thereof.
The casing 40 and the light guide plate 10 are sealed (reference numerals 41 and 42) for the purpose of fixing the position of the light guide plate 10, waterproofing, and dustproofing. The casing 40 can be configured so that the license plate 100 can be slidably inserted into the casing 40 from above, below, or from the side. For example, an opening for inserting a license plate is provided on the upper surface of the casing 40. As described above, the lighting device 1 incorporating the license plate 100
Is installed and fixed to the body 70 of the automobile using the screws 50 and 51 (see FIG. 3).

Next, the illumination mode of the illumination device 1 will be described.
First, each L is linked to the lighting of the side lights (small lights).
Electric current is supplied to the ED 20, and white light is emitted from each LED 20. This white light is introduced into the light guide plate 10 from the upper end surface 13 of the light guide plate 10. The light guided through the light guide plate 10 is reflected and diffused by the groove provided on the light guide plate observation surface 12. As a result, light is generated toward the light guide plate light emitting surface 11, and the light is emitted through the light guide plate light emitting surface 11. Further, the action of the groove promotes diffusion of light in the light guide plate 10. Here, as described above, the upper end surface 13
Since the grooves are formed so that the density becomes higher as the distance from the upper end surface is increased, diffused reflection and diffusion of light are more efficiently performed in a region farther from the upper end surface 13, and the light distribution in the light guide plate 10 is made uniform. Therefore, the light emitted from the light guide plate light emitting surface 11 has extremely reduced unevenness in luminous intensity over the whole. As a result, planar light with uniform luminous intensity is emitted from the light guide plate light emitting surface 11. Therefore, the surface of the license plate is illuminated by the surface light (white light) with less unevenness in illuminance, and the visibility of the characters and numbers displayed there is effectively enhanced.

FIG. 4 shows a perspective view of a license plate illuminating device 2 (hereinafter referred to as "illuminating device 2") which is another embodiment of the present invention. The same members in the lighting device 2 as those in the lighting device 1 are designated by the same reference numerals, and the description thereof will be omitted. In the lighting device 2, a casing 45 having openings on the lower surface side and the lower surface side is used (see FIG. 4). A plurality of LEDs 20 are built in the casing 45 as in the above-described lighting device 1, and each LED 20 is arranged so as to face the upper end surface of the light guide plate 10.

The lighting device 2 uses screws 50 and 51,
At the same time as the license plate 100 is attached, it is installed and fixed to the body 70 of the automobile (see FIG. 5). As shown in FIG. 5, the license plate 100 is sandwiched between the light guide plate 10 and the body 70.

When the illuminating device 2 is used, the surface of the license plate 100 is illuminated by the planar light emitted from the light emitting surface 11 of the light guide plate and the visibility thereof is enhanced. Light is also emitted from the lower end surface and the left and right end surfaces. That is, the end face of the light guide plate emits light and is observed. This light emission has a decorative effect and improves the design of the license plate portion. As described above, in the configuration of the illumination device 2, the light from the LED light source is used for both improving the visibility of the license plate portion and providing decorativeness.

FIG. 6 shows a license plate illuminating device 3 (hereinafter referred to as "illuminating device 3") which is another embodiment of the present invention. FIG. 6 shows a state in which the lighting device 3 is fixed to the body 70. 6, the same members as those of the illumination device 1 or 2 described above are denoted by the same reference numerals, and the description thereof will be omitted.
In the lighting device 3, the light guide plate 60 in which the concave portion 63 is formed on the side facing the license plate 100 is used. The recess 63 is formed in the entire area of the light guide plate 60 except for the edge 64 so that the plan view area thereof is slightly larger than the plan view area of the license plate 100. The bottom surface 61 of the recess 63 is mirror-like. A light diffusion layer (not shown) is formed on the surface (observation surface) 62 of the light guide plate opposite to the side where the recess 63 is formed. This light diffusion layer is a layer in which acrylic beads having an average particle diameter of about 10 μm are dispersed in a base material made of an acrylic resin, and the thickness thereof is about 12 μm.
Is. The content of acrylic beads in the light diffusing layer is 40 based on the weight of the base material 100. Such a light diffusing layer can be formed by printing or applying a clear ink containing a desired amount of acrylic beads on a region of the light guide plate observation surface 62 where the light diffusing layer is to be formed. By printing, it is possible to easily form a light diffusion layer having a desired plan view pattern (for example, a dot matrix shape).

Edge 6 of the light guide plate on the license plate 100 side
A groove 65 is formed on the entire circumference of the groove 4, and a seal member 67 is loaded in the groove 65 when the lighting device 3 is used. The seal member 67 is made of silicone rubber and seals between the light guide plate 60 and the body 70 to prevent rainwater and dust from entering the lighting device 3 (the space where the license plate 100 is installed). To do. Here, in the lighting device 3, the seal member 67 directly seals the space between the light guide plate 60 and the body 70 in this way, and the support plate (base frame) is not interposed between the light guide plate 60 and the body 70. That is, the support plate is omitted. As a result, the configuration of the lighting device 3 becomes simpler,
At the same time, weight reduction and manufacturing cost reduction are achieved by reducing the number of parts. Reference numeral 46 in the drawing is a casing that also serves as a design cover, and is attached to the light guide plate 60 so as to cover the outer edge portion of the light guide plate 60. When the lighting device 3 is installed, a part of the casing 46 is fixed to the body 70.

In the illuminating device 3 as well, similar to the case of the illuminating device 1, good diffusion of light is performed in the light guide plate 60 by the action of the light diffusion layer formed on the observation surface 62 of the light guide plate 60. As a result, planar light with little unevenness in luminous intensity is emitted from the light emitting surface 61 of the light guide plate 60. As a result, the visibility of the letters and numbers displayed on the surface of the license plate 100 is effectively enhanced. In addition, in the illuminating device 3, only the license plate 100 is fixed to the body 70 with the screw 50 to perform sealing. Therefore, it is not necessary to provide the light guide plate 60 with a hole for sealing. Accordingly, the light guide plate 60
The diffusion of light in the interior is further homogenized, and light is emitted from the entire light guide plate light emitting surface 61, so that an illumination aspect having an extremely excellent design is obtained.

FIG. 7 shows a license plate illumination device 4 (hereinafter referred to as "illumination device 4") which is another embodiment of the present invention. FIG. 7 shows a state in which the lighting device 4 is fixed to the body 70. In FIG. 7, the same members as those of the illumination device 1 or 2 described above are designated by the same reference numerals, and the description thereof will be omitted.
In the lighting device 4, the light source unit 80 is configured as a separate body from the light guide plate 90. The light source unit 80 is a cylindrical case 81.
And the LED 20 mounted therein via the substrate 25. In the case 81, a portion (lower side wall) to be located in the light emission direction of the LED 20 is formed of a light transmissive material. The other parts of the case 81 are made of a light impermeable material. Case 8 like this
1 can be produced by two-color molding using a colorless acrylic resin and a colored acrylic resin such as black. Further, in the case 81, the inner walls other than the lower side wall may be formed of a reflective material. In the usage pattern shown in FIG. 7,
After fixing the light source unit 80 to the body 70, the garnish 110 is formed so as to cover the surface of the light source unit 80.
Is installed.

The light guide plate 90 is made of an acrylic resin material, is a flat plate member having a thickness of about 4 mm, and is substantially the same in plan view shape as the license plate 100. On the light guide plate surface (observation surface) 92 opposite to the license plate 100,
Similar to the light guide plate 10 in the illuminating device 1, a number of substantially triangular grooves extending in a dotted line in the vertical direction are formed so as to be staggered in the horizontal direction. On the other hand, the light guide plate surface (light emitting surface) 91 on the license plate 100 side is mirror-finished.

The light guide plate 90 is connected to the support plate 97 in such a manner that its upper portion can be opened and closed by a hinge mechanism (not shown) provided at the lower end thereof. License plate 100
When attaching (or detaching) the license plate 100, the hinge plate is used to pull the upper part of the light guide plate 90 toward the front side to open it, and the license plate 100 is placed at a predetermined position.
Place on top of 7. The light guide plate 90 is temporarily held in a state opened by a predetermined angle (reference numeral 95) by the action of the stopper provided in the hinge mechanism. Due to the action of the stopper, workability at the time of attaching (or detaching) the license plate is improved.

In the illuminating device 4 configured as described above, L
The light emitted from the ED 20 passes through the lower portion (light-transmitting portion) of the case 81, is once extracted to the outside, and is then introduced into the light guide plate 90 from the upper end surface of the light guide plate 90. Then, as in the case of the illumination device 1, good light diffusion is performed in the light guide plate 90 by the action of the groove formed in the light guide plate observation surface 92, and as a result, the planar light with less unevenness of light intensity is guided. The light is emitted from the light emitting surface 91 of the light plate. As a result, the visibility of the letters and numbers displayed on the surface of the license plate 100 is effectively enhanced. In the lighting device 4, the light source unit 80 is provided separately from the light guide plate 90, so that the light source unit 80 can be waterproofed with a simple structure. Further, the light source unit 80 does not move when the license plate 100 is attached (and removed),
The possibility that the light source unit 80 will be damaged by the mounting (detachment) work is extremely small. Further, the wiring mode to the light source unit 80 is also simplified. As described above, according to the configuration of the illumination device 4, a highly reliable and simpler illumination device is provided.

In the above lighting devices 1 to 4, LE is used as a light source.
Although D is used, a bulb, a cold cathode tube, or the like can be used instead of this.

The present invention is not limited to the above description of the embodiments of the invention. Various modifications are also included in the present invention within a range that can be easily conceived by those skilled in the art without departing from the scope of the claims.

[0046]

According to the present invention, by disposing the light guide plate on the front side of the license plate, it is not necessary to incline the license plate in consideration of light irradiation efficiency. Therefore, the license plate portion can be made extremely thin. You can In addition, as shown in the embodiments, the lighting device of the present invention is highly versatile because it can be applied to a general license plate rather than a specially processed one. Further, unlike the conventional letter-light type, it does not require a special license plate, and its configuration is simple. Also,
In one aspect of the present invention, it is possible to install and fix the license plate (and the rear part of the vehicle body such as the bumper and the trunk lid) on the license plate only by using a screw that is usually used for fixing the license plate. Needless to say, it can be used as a retrofit part to an existing automobile, and its range of use is wide. in addition,
By performing illumination with a high illumination effect by the planar light, it is possible to effectively enhance the visibility and design of the license plate portion.

The following matters will be disclosed below. (10) The light source is arranged to face an end surface of the light guide plate, and a surface of the light guide plate opposite to the license plate side is formed with a surface that tapers toward the license plate side as the distance from the end surface increases. Claims 1-9
The lighting device according to any one of 1. (11) The illumination device according to any one of claims 1 to 9 and (10), which includes a cover that covers the light source and the end surface and the edge portion of the light guide plate. (12) A cover for covering the light source is provided.
9. The lighting device according to any one of 9 and (10). (13) The lighting device according to any one of (1) to (9), including a cover that covers a part of an end surface of the light source and the light guide plate. (14) A cover for covering the light source and a part of an end surface of the light guide plate and an edge portion continuous with the end surface is provided.
~ 9, the lighting device according to any one of (10). (15) The illumination device according to any one of (1) to (9), wherein the plan view shape of the light guide plate is substantially the same as that of the license plate. (20) A number characterized by introducing light from a light source into a light guide plate arranged on the front side of a license plate, and radiating the introduced light from the license plate side surface of the light guide plate to illuminate the license plate surface. How to illuminate the plate. (21) The illumination method according to (20), characterized in that light from the light source is introduced through an end surface of the light guide plate. (22) The illumination method according to (20) or (21), wherein the light source emits white light, and illumination is performed with white light. (23) (20) to (2), wherein the light source is an LED.
The illumination method according to any one of 2).

[Brief description of drawings]

FIG. 1 is a perspective view showing a license plate illuminating device 1 which is an embodiment of the present invention.

FIG. 2 is a sectional view taken along the line AA in FIG.

FIG. 3 is a cross-sectional view showing how the license plate lighting device 1 is attached.

FIG. 4 is a perspective view showing a license plate lighting device 2 according to another embodiment of the present invention.

FIG. 5 is a cross-sectional view showing a mounting mode of the license plate lighting device 2.

FIG. 6 is a sectional view showing a license plate lighting device 3 according to another embodiment of the present invention.

FIG. 7 is a sectional view showing a license plate lighting device 4 according to another embodiment of the present invention.

[Explanation of symbols]

1 2 3 4 License plate lighting device 10 60 90 Light guide plate 11 61 91 Light guide plate Light emitting surface 12 62 92 Light guide plate observation surface 13 Light guide plate upper end surface 20 white LED 30 Support plate 40 45 46 casing 50 51 screw 80 light source unit 81 Light source unit case 100 license plate

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Akihiro Misawa             Aichi Prefecture Kasuga-cho, Nishikasugai-gun Ochiai character Nagahata 1             Address within Toyoda Gosei Co., Ltd. (72) Inventor Keima Obito             Aichi Prefecture Kasuga-cho, Nishikasugai-gun Ochiai character Nagahata 1             Address within Toyoda Gosei Co., Ltd. F term (reference) 3K039 LB01 LB05 LD06 LE17

Claims (9)

[Claims] 1. A lighting device comprising: a light source; and a light guide plate disposed on the front side of the license plate, the light guide plate introducing the light from the light source and radiating the introduced light from the license plate side surface. 2. The lighting device according to claim 1, wherein a concavo-convex portion is formed on a surface of the light guide plate on the license plate side and / or a surface opposite to the license plate side. 3. The lighting device according to claim 1, wherein the light source is arranged so as to face an end surface of the light guide plate. 4. The lighting device according to claim 1, wherein the light source is configured as a separate body from the light guide plate. 5. The lighting device according to claim 4, wherein the light source is fixed to a vehicle side and the light guide plate is connected to the vehicle in an openable and closable state when in use. 6. The lighting device according to claim 1, further comprising a seal member that directly seals between a peripheral portion of the light guide plate and a vehicle body when in use. 7. The light source comprises an LED.
The illumination device according to any one of 6 above. 8. The illumination according to claim 1, wherein the light source includes a plurality of LEDs, and the plurality of LEDs are linearly arranged so as to face one end surface of the light guide plate. apparatus. 9. The lighting device according to claim 1, wherein the light source emits white light.