JP3641665B2 - Edge light panel and production method thereof - Google Patents

Description

[0001]
[Industrial application fields]
The present invention relates to an edge light panel for an edge light illuminating device used for a liquid crystal backlight of a television receiver, a computer or the like, or other backlighting, and a method for producing the same.
[0002]
[Prior art]
This kind of edge light illuminating device including a liquid crystal backlight is used to illuminate the incident light from the primary light source that is arranged on the incident end face by irregular reflection in the surface and to guide the incident light in the light source separation direction. , Edge light panels provided with irregular reflection means are used.
[0003]
The irregular reflection means comprises a halftone dot pattern in which an area ratio is increased stepwise in the light source separation direction in an equally spaced matrix arrangement as disclosed in Japanese Patent Laid-Open No. 63-62104 of the present inventors. A screen printed on a transparent substrate is most commonly used, and this edge light panel is particularly suitable for a liquid crystal backlight to ensure brightness and uniformity, and is used as a liquid crystal backlight. Was pioneered and its practical application was realized.
[0004]
[Problems to be solved by the invention]
However, liquid crystal backlights using this kind of edge light panel are limited to those for monochrome liquid crystal display surfaces. In general, backlights for color liquid crystal display surfaces require significantly improved high brightness. However, it is difficult to apply the above-mentioned edge light panel as a liquid crystal backlight for these colors, and even if this is actually done, the luminance is insufficient and cannot be practically used.
[0005]
Naturally, the luminance can be improved considerably by increasing the number of primary light sources, such as arranging the primary light sources in two upper and lower stages. However, increasing the number of primary light sources in this way leads to an increase in the thickness and power consumption of the edge light illumination device. For example, it is conspicuous in portable television receivers, computers, word processors, and the like. As described above, this type of liquid crystal display device goes against the trend of thinning and power saving, and cannot be used as a means for improving luminance as a liquid crystal backlight mounted on these devices.
[0006]
The present invention has been made on the basis of such circumstances, and the subject of the present invention is a high-luminance edge that can maintain the characteristics of the edge light panel as being thin and uniform and can realize a dramatic improvement in luminance. It is in providing a light panel and its production method.
[0007]
[Means for Solving the Problems]
As a result of diligent research along the above-mentioned problems, the present inventors have found that when the laminated reflecting means is arranged in close contact with the irregular reflecting means such as the halftone dot pattern so as to cover a part or all of the surface thereof. In this case, the diffused light reflection means is made of a transparent resin integrally formed with the transparent substrate, and the laminated reflection means is an ultraviolet curable reflection containing a reflective pigment. Forming a reflective ink or a thermal transfer layer, making the irregular reflection means into a micro hemisphere and covering it with the multilayer reflection means, making the irregular reflection means into a minute rectangular shape or a trapezoidal shape or a minute bulge, and forming the multilayer reflection layer It is known that covering the top surface part of the surface partially, making the top surface part of the transparent resin into a bowl shape, etc. are effective for the above dramatic brightness improvement or advantageous in production. It was obtained.
[0008]
The present invention has been made on the basis of such knowledge, and the invention described in claims 1 to 4 is an invention relating to an edge light panel, and the invention described in claim 1 is applied to the back surface of the transparent resin substrate. Random reflection means formed so as to steplessly expand the area ratio in the direction of light source separation with a transparent resin integrally molded with the resin substrate, and thermal transfer containing a reflective pigment so as to cover part or all of the surface of the irregular reflection means An edge light panel comprising a layered reflection means formed in close contact with the irregular reflection means by a layer, wherein the irregular reflection means is formed in a micro hemispherical shape. The laminated reflection means is formed so as to substantially cover the entire surface of the irregular reflection means. The edge light panel according to claim 1, wherein the invention according to claim 3 2. The edge according to claim 1, wherein the projecting means is formed in a minute rectangular shape or a trapezoidal shape or a minute bulging shape, and the laminated reflective layer is formed so as to partially cover the top surface portion of the irregularly reflecting means surface. A light panel is provided, and the invention according to claim 4 is the edge light panel according to claim 1 or 3, wherein the top surface portion of the irregular reflection means surface is roughened in a bowl shape. The invention described in No. 5 is an invention relating to a method for producing an edge light panel, and this is applied to a transparent substrate provided with irregularly reflecting means for transparent resin by integral molding on the back surface so as to increase the area ratio steplessly in the light source separation direction. On the other hand, a method for producing an edge light panel, characterized in that a thermal transfer step of forming a partial laminated reflecting means on the top surface portion of the irregular reflecting means surface is performed by a thermal transfer sheet containing a reflective pigment. A. The present invention uses each of these as the gist of the invention as means for solving the above problems. In the present invention, the laminated reflecting means is formed on the surface or top portion of the irregular reflecting means. When the laminated reflecting means is formed so as to cover the transparent substrate surface outside the irregular reflecting means in the transparent resin substrate, the transparent reflecting means is transparent. The laminated reflecting means formed on the substrate surface exhibits an incident light absorbing function and depletes the amount of incident light on the transparent substrate, which is a hindrance to the realization of dramatic brightness improvement according to the present invention. The laminated reflecting means is used to exclude those formed so as to cover the transparent resin substrate surface.
[0009]
[Action]
In the present invention, the diffused reflection means or the laminated reflective means arranged in close contact with the transparent substrate via the diffused reflection means directs the incident light reaching the diffused reflection means toward the front side of the edge light panel, that is, the illumination surface side. Therefore, the luminance is improved by reflecting or irregularly reflecting as much as possible and preventing the incident light emission outside the back surface as much as possible. In the invention according to claim 2, the condensing effect by the lens is set so that the irregular reflection means and the multilayer reflection means are focused on the position in the edge light panel by making the irregular reflection means a micro hemisphere and covering the multilayer reflection means. As a result of the fact that the condensing part shines, the brightness of the edge light panel is further improved.
[0010]
【Example】
Hereinafter, the present invention will be described in more detail with reference to the drawings showing embodiments. In FIGS. 1 and 2, reference numeral 10 denotes an edge light panel of a liquid crystal backlight mounted on a liquid crystal display device. For example, a diffusion sheet made of a milk white polyester film having a thickness of 75 μm is formed on the front surface side, and a reflection sheet made of a white polyester low foam film having a thickness of 75 μm and bent in a C-shaped cross section on the back surface side. By arranging a tube-shaped primary light source composed of a cold cathode tube on the incident end face 12 as one end face on one side as an incident end face 12 and a reflection end face 13 having a mirror finish on the opposite end face to increase the reflectivity. It is intended to be used to constitute a liquid crystal backlight.
[0011]
The edge light panel 10 includes irregular reflection means 20 formed on the back surface of the transparent resin substrate 11 so as to increase the area ratio steplessly in the light source separation direction by using a transparent resin integrally formed with the transparent resin substrate 11, and the irregular reflection means 20. And the laminated reflection means 30 formed in close contact with the irregular reflection means 20 by a thermal transfer layer containing a reflective pigment so as to cover part or all of the surface of the irregular reflection means. 20 is formed into a small rectangular shape or a trapezoidal shape or a minute bulging shape, in this example, a minute trapezoidal shape, and the top surface portion of the surface of the irregular reflection means 20 formed in the minute trapezoidal shape has a bowl shape. The laminated reflecting means 30 is formed so as to partially cover the top surface portion of the irregularly reflecting means 20 surface.
[0012]
In this example, the edge light panel 10 has a top surface portion on the surface of the irregular reflection means 20 by a thermal transfer sheet containing a reflective pigment with respect to the transparent resin substrate 11 provided with the irregular reflection means 20 of the transparent resin by integral molding. This is produced by performing a thermal transfer process for forming a partial laminated reflecting means 30 on the substrate.
[0013]
In the edge light panel 10 of the present example, a halftone dot pattern irregular reflection means 20 is formed on the back surface of a transparent resin substrate 11 made of acrylic resin, and the halftone dot pattern is arranged in an equally spaced matrix to change its positional relationship. Without increasing the area ratio steplessly, the area ratio was gradually increased steplessly from the incident end face 12 side of the transparent resin substrate 11 toward the inner surface of the separation surface. At this time, in the present example, the peak position having the maximum area ratio is set to the intermediate position between the incident end face 12 and the reflecting end face 13 so as to gradually increase from the reflecting end face 13 side as well. The pattern irregular reflection means 20 is based on a peak position displacement pattern, whereby the entire edge light panel 10 is made uniform by supplying incident light from one primary light source on one side. It is then adapted to control the diffused reflection amount such that the luminance.
[0014]
That is, the edge light panel 10 in this example is relatively small, for example, 4 mm thick to 77 mm × 125 mm so that the warp during the molding can be prevented by integrally molding the edge light panel 10. Further, the irregular reflection means 20 by the halftone dot pattern is arranged so as to have a trapezoidal shape having a minute height of about 20 to 50 μm, and in this example, a minute height of about 20 to 30 μm. Yes, at this time, the edge light panel 10 is molded by using a molding die in which a halftone dot pattern is formed by, for example, a photoetching method. By controlling the etching conditions such as the processing time or the amount of these liquids used in the etching of acid, alkali, etc. The bottom wall of the halftone dot is roughened like a bowl, and the edge light panel 10 is molded using the molding die so as to perform the integral molding. The top surface is roughened in the above-mentioned bowl shape.
[0015]
The irregular reflection means 20 of the edge light panel 10 formed by integrally molding in this way has its top surface roughened like a bowl and improves irregularity by promoting irregular reflection. The roughening of the top surface portion in the example requires that the surface be roughened while being flat enough not to interfere with the formation of the laminated irregular reflection means 30 by thermal transfer.
[0016]
The laminated irregular reflection means 30 of this example forms this as a thermal transfer layer on the top surface portion by the above thermal transfer process. In this thermal transfer process, for example, a white thermal transfer sheet containing, for example, titanium oxide toner as a reflective pigment (for example, Is placed on the top surface of the irregularly reflecting means 20 of the transparent resin substrate 11 so as to continuously contact the roller, and the roller is rolled under heating at 80 ° C., for example. Thus, the irregular reflection means 30 may be formed by thermal transfer on the top surface of each halftone dot in this example.
[0017]
At this time, the thermal transfer sheet is slightly tensioned so that the transfer layer is formed on the transparent resin substrate 11 other than the top surface portion of the irregular reflection means 20, so that the transfer layer is other than the irregular reflection means 20. Therefore, it is necessary to form the laminated irregular reflection means 30 so as to prevent the incident light absorbing function from being exhibited.
[0018]
The edge light panel 10 thus configured further reflects as much as possible the incident light that the diffuse diffuse reflection means 30 reaches the irregular reflection means 20 and diffusely reflects, and emits incident light out of the back surface of the edge light panel 10. It is possible to prevent and to dramatically improve the brightness.
[0019]
The illustrated example is as described above. However, the irregular reflection means is formed in a micro hemisphere, and the laminated reflection means is formed so as to substantially cover the entire surface of the irregular reflection means. In the present invention, it is inappropriate to form the irregular reflection means so as to have a concave shape. However, the height of the irregular reflection means is not suitable for the transparent substrate. In contrast, the shape should be as small as about 20 to 50 μm, the shape should be a micro-cylindrical shape, and the cross-sectional shape should be a suitable shape such as a micro trapezoidal shape, a mountain shape, and a bulging shape. In addition to horizontal ones, it should be curved and bulged, the pattern of irregular reflection means arrangement should be a radial or reverse radial line or halftone dot pattern, and heat transfer using a thermal transfer sheet of laminated reflection means Use method If the temperature of the thermal transfer is, for example, a transparent resin substrate made of acrylic resin, the temperature should be about 130 ° C. or less so as not to be affected by this. The laminated reflecting means is of a mirror type by heating at about 80 ° C. so that thermal transfer can be reliably performed, and by using a metallic toner such as aluminum as the reflective pigment. Edge light panels, transparent resin substrates, diffuse reflection means, laminated reflection means, thermal transfer sheets to be used as needed, specific materials, shapes, structures, applications, production methods for the thermal transfer process, etc. The relationship, addition to these, etc. can be in various forms as long as they do not contradict the gist of the invention.
[0020]
【The invention's effect】
Since the present invention is configured as described above, the invention according to claims 1 to 4 forms the laminated reflecting means in the irregular reflecting means, so that the production can be performed relatively easily and the laminated reflecting means is Since the thermal transfer layer is formed in close contact with the diffuse reflection means, it does not increase the thickness of the edge light panel, and thus can improve brightness dramatically by several percent or more. A high-luminance edge light panel can be provided, and an edge-light panel suitable for a liquid crystal backlight for a color liquid crystal display surface can be provided. A production method suitable for the production of edge light panels can be provided.
[Brief description of the drawings]
FIG. 1 is an enlarged vertical sectional view of an edge light panel.
FIG. 2 is a rear view of the edge light panel.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Edge light panel 11 Transparent resin board | substrate 12 Incident end surface 13 Reflective end surface 20 Random reflection means 30 Laminated reflection means

Claims (5)

The irregular reflection means formed on the back surface of the transparent resin substrate so as to increase the area ratio steplessly in the light source separation direction by the transparent resin integrally molded with the transparent resin substrate, and a part or all of the surface of the irregular reflection means is covered An edge light panel, comprising: a reflective layer containing a reflective reflection layer formed in close contact with the irregular reflection unit by a thermal transfer layer containing a reflective pigment. 2. The edge light panel according to claim 1, wherein the irregular reflection means is formed in a minute hemisphere, and the laminated reflection means is formed so as to substantially cover the entire surface of the irregular reflection means. 2. The irregular reflection means is formed in a minute rectangle or a trapezoidal shape or a minute bulge, and the laminated reflection means is formed so as to partially cover the top surface portion of the irregular reflection means surface. Edge light panel. 4. The edge light panel according to claim 1, wherein the top surface portion of the irregular reflection means is roughened in a bowl shape. The top surface of the surface of the irregular reflection means is formed by a thermal transfer sheet containing a reflective pigment on a transparent substrate having an irregular reflection means of transparent resin integrally molded so as to steplessly increase the area ratio in the light source separation direction on the back surface. A method for producing an edge light panel, wherein a thermal transfer process for forming a partial laminated reflection means is performed on the edge light panel.

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