JP3561714B2 - Light guide plate type circular light emitting display - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a traffic sign displaying traffic information such as a speed limit or a no-entry road, and a light guide plate type circular light emitting display used for a signboard for advertisement and publicity, and more particularly to a support for a large light guide plate. The present invention relates to a light guide plate type circular light emitting display having a structure.
[0002]
[Prior art]
Conventionally, lighting methods for outdoor traffic signs and signboards include an external illumination type that illuminates the display surface with a light source such as a neon tube or fluorescent tube, and an internal illumination type that illuminates the display surface from inside the sign. It has been known. Recently, a surface-emitting method has been attracting attention as an illumination method having no unevenness in brightness (for example, see Patent Document 1).
[0003]
[Patent Document 1]
JP-A-11-140830 (page 2, FIG. 1-5)
[0004]
The surface emission method is a method mainly used for a backlight of a liquid crystal display, and an EL (electroluminescence) method and a light guide plate method are conventionally known. In the EL method, an AC pulse is applied to a light-emitting layer composed of a solid inorganic thin film laminated on a substrate, and high-energy electrons are generated by the electric stimulation, and the energy is emitted as light when returning to a ground state. This is a phenomenon that takes advantage of the phenomenon.
[0005]
On the other hand, in the light guide plate system, light is introduced from the end surface of a light guide plate made of a material with high refractive index and transmittance such as a transparent plastic plate, and one surface (reflection surface) of which is subjected to special processing such as dot printing or embossing. Then, the light is totally reflected inside the light guide plate, and the light is emitted from the surface (light output surface) of the light guide plate, which is the opposite surface by changing the direction on one surface (reflection surface) specially processed, that is, It utilizes the prism effect. At present, such a light guide plate system is mainly used for a backlight of a liquid crystal display.
[0006]
[Problems to be solved by the invention]
However, in the conventional illumination system using a neon tube or a fluorescent tube as described above, 1) vibration or impact is applied, or the connection or the filament in the neon tube or the fluorescent tube is broken due to deterioration or the like, so that the so-called “unusable” is used. "Breakdown problem", 2) "Maintenance problem" that requires a short life and requires regular maintenance and replacement, 3) "Consumption" which requires a lot of power due to light emission using the discharge phenomenon Problems have been pointed out, such as "problems with power" and 4) "complex device configuration" which requires additional devices such as starter lamps, transformers, and stabilizers in addition to neon tubes and fluorescent tubes.
[0007]
On the other hand, in the illumination method using the EL method, which is a surface-emitting method, the emission color of the EL is bluish-green. Therefore, when used as a backlight of a light guide plate type light emitting display, an orange color sheet is provided on the EL plate. It is necessary to take measures such as whitening the emission color, which causes "cost increase". In addition, problems such as "low brightness" and "short life" due to aging are pointed out.
[0008]
Further, in the light guide plate method, since light is incident from the end face of the light guide plate by a point light source, problems such as "light ray streaks appear on the light emission surface" and "light / dark unevenness" appear. Further, when a large circular light guide plate having a large display surface area with respect to the thickness is used, in addition to solving these problems, it is difficult to fix the light guide plate to the housing. The practical application of the circular light emitting display has been hindered.
[0009]
That is, as a method of fixing the light guide plate to the housing, screwing with a fixing tool such as a spiral, bonding to a reinforcing plate such as a metal plate or the like can be considered, but if a light guide plate is provided with a fixing spiral hole or the like. Since the propagation of light is disturbed at that portion, problems such as "a shadow is projected on the display surface" and "light emission unevenness" occurs. On the other hand, if the light guide plate is adhered and fixed to the metal plate, the vibration is directly transmitted to the light guide plate, causing "deterioration / breakage of the light guide plate". The difference in the thermal expansion coefficient between the light guide plate and the metal plate causes problems such as "stress is applied to the light guide plate", and the use of the metal plate causes "the weight of the device increases".
[0010]
Therefore, an object of the present invention is to provide a light guide plate type circular light emitting display which has no problem of broken balls, requires no maintenance (maintenance free), consumes little power, has low manufacturing costs, and has little light streaks and uneven brightness. An object of the present invention is to provide a light guide plate type circular light-emitting display device having a light guide plate support structure that suppresses generation of stress and propagation of vibration without projecting a shadow on a display surface in order to put the device into practical use.
[0011]
[Means for Solving the Problems]
In order to achieve the above object, the invention according to claim 1 is a light guide plate type circular light emitting display comprising a light guide plate, a dial plate, a light source arranged on a side surface of the light guide plate, and a housing for housing them. The light source is composed of a plurality of linear light-emitting bodies constituted by light-emitting diodes arranged in a row, is arranged in a concave portion provided on the peripheral surface of the light guide plate, and is engaged and held by the light guide plate, and the housing is provided on the inner wall. The light guide plate and the dial are housed by contacting the outer edges of the light guide plate to regulate the movement of the light guide plate in the radial direction, and the elastic plate is compressed and inserted between the light guide plate and the bottom surface of the housing. Then, a configuration is adopted in which the movement of the light guide plate in the thickness direction is restricted by the repulsive force of the elastic plate.
[0012]
Here, the material of the elastic plate used in the present invention is not limited to a specific material as long as sufficient elasticity can be obtained, but it is lightweight and has excellent cushioning property and durability. Polyurethane foam is preferably used because it has good shock absorption, heat insulation, heat resistance, and chemical resistance, and is easy to perform various processes such as cutting, punching, and bonding.
[0013]
[Action]
According to the present invention, there is provided a light guide plate type circular light emitting display including a light guide plate, a dial, a light source arranged on a side surface of the light guide plate, and a housing for accommodating them, wherein the light sources are arranged in rows. Composed of a plurality of linear light emitters constituted by light emitting diodes, arranged in a concave portion provided on the peripheral surface of the light guide plate, and engaged with and held by the light guide plate, so that there is no displacement between the light guide plate and the light source, and The housing contacts the outer edge of the light guide plate with the inner wall to house the light guide plate and the dial, restricting the movement of the light guide plate in the radial direction, and compressing the light guide plate and the bottom surface of the housing. The elastic plate is inserted and fitted, and the movement of the light guide plate in the thickness direction is restricted by the repulsive force of the elastic plate, so that the fixing process of the fixture to the light guide plate becomes unnecessary, and the display surface is eliminated. Not only is there no shadow projected on the light guide plate, Raw, propagation of vibration to the light guide plate is suppressed, the light guide plate, the dial plate and a light source not located.
[0014]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, preferred embodiments of a light guide plate type circular light emitting display according to the present invention will be described with reference to the drawings. FIG. 1 is a partially cutaway perspective view of a light guide plate type circular light emitting display according to the present invention, and FIG. 2 is a schematic sectional view of a light guide plate type circular light emitting display according to the present invention. In FIG. 1, the thickness and length are shown on a different scale in order to clearly describe the configuration in the cross section.
[0015]
As shown in the schematic cross-sectional view of FIG. 2, the light guide plate type circular light emitting display according to one embodiment of the present invention shown in FIG. 1 has a light guide plate 1 made of a transparent plastic plate having a thickness of 10 mm and a maximum diameter of 873 mm. A dial plate 4 made of a transparent plastic plate provided facing the upper surface (light emitting surface 1b) of the light guide plate 1, and a reflective plate 3 made of an aluminum plate provided on the lower surface (reflective surface 1a) side of the light guide plate 1. Has a laminated structure. A number indicating the speed limit is printed on the inner surface of the dial 4 (the surface on the side of the light guide plate), and on the reflection surface 1a of the light guide plate 1, the side of the light guide plate (light entrance end). A dot pattern is printed to scatter and reflect light that enters from 1c) and is totally reflected inside the light guide plate 1.
[0016]
These laminated structures are composed of an upper and lower divided housing consisting of a cylindrical lid housing 7a having an opening 7c for exposing the display surface of the dial 4 and a bottomed cylindrical bottom housing 7b. It is housed together with an elastic plate 13 made of resin or the like, is aligned with the open side edges of the two divided housings, and is pressed against by the case fastener band 9 so as to be urged with a uniform pressure from the rear surface. It is supported and fixed in the housing. The lid housing 7a and the bottom housing 7b are both made of aluminum, and the surface is subjected to a so-called alumite treatment for forming an anodic oxide film, thereby improving decorativeness and rust prevention.
[0017]
The thickness of the elastic plate 13 and the height of the housing need to be at least larger than the thickness of the light guide plate in order to apply sufficient pressure to the laminated structure. When the lid housing 7a and the bottom housing 7b are aligned, that is, when a single housing is formed by the lid housing 7a and the bottom housing 7b, the elasticity of the elastic plate 13 is sufficient for the laminated structure. , The height of the housing composed of the lid housing 7a and the bottom housing 7b is adjusted. In this embodiment, the elastic plate 13 made of urethane resin having a thickness of 40 mm is compressed to 20 mm by the alignment of the lid housing 7a and the bottom housing 7b, and the elasticity is uniformly applied to the entire surface of the light guide plate 1. It is being rushed. The elasticity of the elastic plate 13 not only enables the light guide plate 1 to be urged, but also allows the wire harnesses 11 and 12 and the connector 10 connected to the light source to follow the housing bottom without requiring any special support member. Can be held.
[0018]
In FIGS. 1 and 2, members indicated by reference numerals 6 and 8 are waterproof packing for preventing rainwater or the like from entering the inside of the light guide plate type circular light emitting display from outside. In this embodiment, a synthetic rubber containing polychloroprene as a basic component, which is excellent in light resistance, weather resistance, and chemical resistance, has a wide operating temperature range, and has excellent flame retardancy, is used.
[0019]
Next, the light source used in the present invention will be described in detail with reference to FIG. On a side portion (light incident end 1c) of the light guide plate 1, a linear illuminant for entering light into the light guide plate is installed over the entire circumference of the light guide plate as shown in FIG. I have. In this embodiment, as a linear light emitter, as shown in FIG. 3A, the length of the light guide plate 1 is approximately equal to the length of a chord when the entire circumference of the light guide plate 1 is divided into 24, and the width is the thickness of the light guide plate 1. A light-emitting diode array is used in which a plurality of light-emitting diodes 2 are arranged on an epoxy resin substrate 5 having substantially the same size and in a straight line in parallel with each other.
[0020]
As shown in FIG. 3 (b), the band of light emitted from the 24 linear light emitters reflects the center of the light guide plate 1 while totally reflecting between the light exit surface 1b and the reflection surface 1a of the light guide plate 1. pass. Then, the light is scattered and reflected by dots provided on the reflection surface 1a of the light guide plate 1 by dot printing. As a result of the scattered reflection, light having a component whose incident angle with respect to the light guide plate is smaller than the total reflection angle is emitted from the light exit surface 1b to the outside. Since the reflection plate 3 made of an aluminum plate is disposed in contact with the reflection surface 1a of the light guide plate 1, the scattered and reflected light does not leak behind the light guide plate.
[0021]
Each light emitting diode 2 is printed and wired in series and / or parallel on the back surface of the epoxy resin substrate 5 and connected to a control circuit by a wire harness 11. Also, by coating the front surface 5a of the epoxy resin substrate 5 white, light leaked from the side portion (light incident end 1c) of the light guide plate 1 is reflected and made to enter the light guide plate 1 again. Therefore, the front luminance can be further improved.
[0022]
As shown in FIG. 3 (a), a method for attaching the linear illuminant is to form a recess by cutting out the circumferential end of the light guide plate 1 according to the shape of the illuminant, and to attach the illuminant to the recess. By performing the combined holding, the luminous body can be fixed facing the light guide plate side (light incident end 1c) without using a special holding member. In this case, the back portion 1f of the illuminant support portion 1d formed between the illuminators arranged adjacent to each other contacts the inner wall of the housing and regulates the movement of the light guide plate in the radial direction.
[0023]
In this embodiment, a light guide plate made of a transparent plastic plate having a thickness of 10 mm and a maximum diameter of 873 mm is used, but the size of the light guide plate is not limited to this. However, in the case of a light guide plate having a large area with respect to a thickness such that the aspect ratio α, which is the ratio of the diameter L of the circle inscribed in the incident end face to the thickness T of the incident end face, satisfies the relationship of 80 ≦ α, the outer edge of the light guide plate When the light guide plate is supported by restricting the movement of the light guide plate in the radial direction by the outer edge of the light guide plate and the movement of the light guide plate in the thickness direction due to the elasticity of the elastic plate because the support by the part alone cannot sufficiently secure the light guide plate. In particular, it exerts its effect.
[0024]
【The invention's effect】
According to the invention according to claim 1, a light guide plate type circular light emitting display comprising a light guide plate, a dial, a light source disposed on a side surface of the light guide plate, and a housing for accommodating them, wherein the light source is: It consists of a plurality of linear light-emitting bodies constituted by light-emitting diodes arranged in a row, is arranged in a concave portion provided on the peripheral surface of the light guide plate, and is engaged and held by the light guide plate, and the housing has a light guide plate on the inner wall. The light guide plate and the dial are housed by contacting the outer edges to regulate the movement of the light guide plate in the radial direction, and the elastic plate is compressed and inserted between the light guide plate and the bottom surface of the housing, Since the movement of the light guide plate in the thickness direction is restricted by the repulsive force of the elastic plate, there is no need to attach a fixture or the like to the light guide plate, thereby reducing "production cost" and improving the display surface. "Uniform surface emission luminance" without shadows of the support structure etc. is realized. Since the occurrence of stress in the light guide plate is suppressed, "the life of the light guide plate", "improvement of reliability" can be achieved.
[0025]
The present invention realizes a large light guide plate type circular light emitting display using a light guide plate method, which has been considered to be difficult to put to practical use. Since a light guide plate type circular light emitting display with less unevenness can be obtained, its industrial technical significance is extremely high.
[Brief description of the drawings]
FIG. 1 is a schematic perspective view in which a part of a light guide plate type light emitting display according to an embodiment of the present invention is cut.
FIG. 2 is a schematic sectional view of the light guide plate type circular light emitting display shown in FIG.
FIG. 3 is a view for explaining a mounting structure of a light emitter used in the light guide plate type circular light emitting display shown in FIG. 1;
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Light guide plate 2 ... Light emitting diode 3 ... Reflection plate 4 ... Letter plate 5 ... Epoxy resin board 6 ... Waterproof packing 7 ... Case 8 ... Waterproof packing 9 ... Case fastener band 10 ... Connectors 11, 12 ... Wire harness 13 ... Elastic member

Claims (1)

A light guide plate, a dial, and a light source disposed on a side surface of the light guide plate, and a light guide plate type circular light emitting display including a housing for housing these,
The light source is composed of a plurality of linear light emitters constituted by light emitting diodes arranged in a row, arranged in a recess provided on the peripheral surface of the light guide plate, and is engaged and held by the light guide plate,
The housing accommodates the light guide plate and the dial by bringing the outer edge of the light guide plate into contact with an inner wall, and regulates the movement of the light guide plate in the radial direction. A light guide plate-type circular light emitting display, wherein a compressed elastic plate is inserted between the bottom surfaces, and the movement of the light guide plate in the thickness direction is restricted by the repulsive force of the elastic plate.

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