JP2004184947A - Light guide plate type circular light emission display unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a light guide plate support structure which projects no shadow on a display surface and deters stress from being generated and vibration from being propagated. <P>SOLUTION: The light guide plate support structure for a light guide plate type circular light emission display unit has in a housing 7 a combination of a light guide plate 1, a dial 4, and a light source; and at least a portion of an outer edge of the light guide plate comes into contact with an inner wall of the housing to restrict radial direction movement of the light guide plate and an elastic plate 13 which has a radius nearly equal to the radius of the housing and a thickness larger than the thickness of the light guide plate is fitted between the light guide plate and the bottom surface of the housing to restrict perpendicular-directional movement of the light guide plate with the elastic force of the elastic plate. <P>COPYRIGHT: (C)2004,JPO&NCIPI

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. It is about 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. In recent years, a surface-emitting method has been attracting attention as an illumination method without uneven 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 method using a neon tube or a fluorescent tube as described above, 1) a so-called "use" in which a connection or a filament in the neon tube or the fluorescent tube breaks due to vibration or impact or deterioration or the like due to deterioration or the like. "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. Practical use 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 support structure in which generation of stress and propagation of vibration are suppressed without shadows being projected on a display surface in order to put a practical use of the device.
[0011]
[Means for Solving the Problems]
In order to achieve the above object, an invention according to claim 1 is a light guide plate support structure of a light guide plate type circular light emitting display having a combination of a light guide plate, a dial, and a light source in a housing, wherein the light guide plate is provided. At least a portion of the outer edge of the light guide plate contacts the inner wall of the housing to regulate the movement of the light guide plate in the radial direction, and has a radius substantially equal to the radius of the housing between the light guide plate and the bottom surface of the housing. An elastic plate having a thickness larger than the thickness of the light guide plate is inserted and the movement of the light guide plate in the perpendicular direction is restricted by the elasticity 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]
According to a second aspect of the present invention, in addition to the configuration of the first aspect of the present invention, the housing comprises a bottomed cylindrical bottomed housing and a cylindrical lid housing having an opening window. By aligning the body and the lid housing, the elastic plate is compressed and the elasticity is uniformly urged to the entire surface of the light guide plate.
[0014]
Further, in the invention according to claim 3, in addition to the configuration according to claim 1 or 2, the light guide plate has a ratio L / T of a diameter L of a circle inscribed in the incident end face to a thickness T of the incident end face. Is such that the aspect ratio α satisfies the relationship of 80 ≦ α.
[0015]
[Action]
According to the invention according to claim 1, at least a part of the outer edge of the light guide plate in the light guide plate support structure of the light guide plate type circular light emitting display having a combination of the light guide plate, the dial, and the light source in the housing. Is in contact with the inner wall of the housing and regulates the movement of the light guide plate in the radial direction, and between the light guide plate and the bottom surface of the housing, a radius substantially equal to the radius of the housing and having a thickness greater than the thickness of the light guide plate. The elastic plate is inserted, and the movement of the light guide plate in the perpendicular direction is restricted by the elasticity of the elastic plate. Therefore, the mounting process of the fixture or the like to the light guide plate becomes unnecessary, and the shadow is projected on the display surface. Accordingly, generation of stress in the light guide plate and propagation of vibration to the light guide plate are suppressed.
[0016]
According to the second aspect of the present invention, in addition to the function of the first aspect, the housing comprises a bottomed cylindrical bottom housing and a cylindrical lid housing having an opening window. By aligning the housing and the lid housing, the elastic plate is compressed and the elasticity is uniformly urged to the entire surface of the light guide plate, so that pressure is applied without uneven distribution to the entire surface of the light guide plate. In addition, a special processing step for supporting the light guide plate is not required, and the assembling step is simplified.
[0017]
According to the third aspect of the present invention, in addition to the function of the first or second aspect, the light guide plate has a ratio L / L of the diameter L of the circle inscribed in the incident end face to the thickness T of the incident end face. Since the aspect ratio α as T satisfies the relationship of 80 ≦ α, the light guide plate has a relatively large area with respect to the thickness. And contribute to weight reduction. In addition, despite the large area, the shadow of the support for fixing the light guide plate is not projected on the display surface, and the effective light emitting display area is increased.
[0018]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, preferred embodiments of a light guide plate support structure 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 for explaining a configuration of a light guide plate support structure according to the present invention, and FIG. 2 employs a light guide plate support structure according to the present invention. It is a schematic sectional drawing of the light-guide-plate-type circular light-emitting display device shown. In FIG. 1, the thickness and length are shown on a different scale in order to clearly describe the configuration in the cross section.
[0019]
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 reflector plate 3 made of an aluminum plate provided on the lower surface (reflection surface 1a) 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.
[0020]
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. The housing is accommodated together with the elastic member 13 and the like, and the two divided housings are aligned and pressed by the case fastener band 9 to be supported in the housing in a state of being urged by a uniform pressure from the back surface. Fixed. 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.
[0021]
The thickness of the elastic plate and the height of the housing need to use an elastic plate having a thickness at least larger than the thickness of the light guide plate in order to apply sufficient pressure to the laminated structure. Then, when the lid housing 7a and the bottom housing 7b are aligned, the height of the housing composed of the lid housing 7a and the bottom housing 7b is set so that the elasticity of the elastic member 13 is sufficiently added to the laminated structure. Has been adjusted. In this embodiment, the urethane elastic plate 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 urged to the entire surface of the light guide plate. I have. Due to the elasticity of the elastic plate, not only is it possible to urge the light guide plate, but also the wire harnesses 11 and 12 and the connector 10 connected to the light source are held along the bottom surface of the housing without requiring a special support member. It becomes possible to do.
[0022]
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.
[0023]
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.
[0024]
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 in contact with the reflection surface 1a of the light guide plate 1, the light scattered and reflected does not leak behind the light guide plate.
[0025]
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 (not shown) by a wire harness. 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.
[0026]
The method of attaching the linear illuminant is not particularly limited, but as shown in FIG. 3A, the circumferential end of the light guide plate 1 is cut out according to the shape of the illuminant to form a concave portion. By engaging and holding the luminous body in the concave portion, 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.
[0027]
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 The light guide plate is supported by the outer edge of the light guide plate and the vertical movement of the light guide plate due to the elasticity of the elastic body. The support structure of the invention exerts its effects in particular.
[0028]
【The invention's effect】
According to the invention according to claim 1, in the light guide plate supporting structure of the light guide plate type circular light emitting display having a combination of the light guide plate, the dial, and the light source, at least a part of the outer edge portion of the light guide plate is a housing. In addition to restricting the radial movement of the light guide plate by contacting the inner wall of the light guide plate, an elastic plate having a radius substantially equal to the radius of the housing and having a thickness larger than the thickness of the light guide plate is provided between the light guide plate and the bottom surface of the housing. Since the light guide plate is configured to be inserted and fitted to restrict the movement of the light guide plate in the perpendicular direction by the elasticity of the elastic plate, it is not necessary to attach a fixture or the like to the light guide plate, thereby reducing the manufacturing cost. Further, since the shadow of the support structure or the like is not projected on the display surface, “uniform surface emission luminance” can be realized. Furthermore, since the generation of stress in the light guide plate and the propagation of vibration to the light guide plate are suppressed, “extending the life of the light guide plate” and “improving reliability” can be achieved.
[0029]
According to the invention according to claim 2, in addition to the effects achieved by the invention according to claim 1, the housing is formed of a bottom housing having a bottomed cylindrical shape and a cylindrical lid housing having an opening window. By aligning the housing and the lid housing, the elastic plate is compressed and the elasticity is uniformly urged to the entire surface of the light guide plate, so that pressure is applied without uneven distribution to the entire surface of the light guide plate. In addition, since a special processing step for supporting the light guide plate is not required, "simplification of the assembling step" can be realized.
[0030]
According to the third aspect of the invention, in addition to the effects of the first or second aspect of the invention, the light guide plate has a ratio L / L of the diameter L of the circle inscribed in the incident end face to the thickness T of the incident end face. The aspect ratio α that is T satisfies the relationship of 80 ≦ α, so that the light guide plate has a relatively large area with respect to the thickness, but is used for fixing the light guide plate to the display surface. Since the shadow of the support structure is not projected, the “large-size and light-weight” of the light guide plate type circular light emitting display is achieved.
[0031]
The present invention has realized a large-sized light guide plate type circular light emitting display using a light guide plate, which has been considered difficult to put into practical use, and 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 diagram illustrating a mounting structure of a light emitting body 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 ... Reflector 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 (3)

A light guide plate, a dial, and a light guide plate supporting structure of a light guide plate type circular light emitting display having a combination of a light source and a housing in a housing,
At least a portion of the outer edge of the light guide plate contacts the inner wall of the housing to regulate movement of the light guide plate in the radial direction,
An elastic plate having a radius substantially equal to the radius of the housing and having a thickness greater than the thickness of the light guide plate is inserted between the light guide plate and the bottom surface of the housing, and the elasticity of the elastic plate allows the light guide plate to be inserted. A light guide plate support structure for a light guide plate type circular light emitting display, wherein movement of the light guide plate in a perpendicular direction is restricted. The housing is composed of a cylindrical lid housing having a bottom housing having a bottomed cylindrical shape and an opening window,
2. The light guide according to claim 1, wherein by aligning the bottom housing and the lid housing, the elastic plate is compressed and the elasticity is uniformly urged to the entire surface of the light guide plate. 3. Light guide plate support structure of light plate type circular light emitting display. 2. The light guide plate according to claim 1, wherein an aspect ratio α, which is a ratio L / T of a diameter L of a circle inscribed in the incident end face to a thickness T of the incident end face, satisfies a relationship of 80 ≦ α. A light guide plate supporting structure for a light guide plate type circular light emitting display according to claim 2.

Images