JPH06194527A - Photoconductive plate - Google Patents

Abstract

PURPOSE:To obtain a convenient photoconductive plate excellent in mass productivity at a lower cost by transiently printing a reflecting pattern on a thin sheet of plastic, etc., and bonding the sheet to an acrylate sheet. CONSTITUTION:A rear reflecting pattern 3 is previously formed on a thin white plastic sheet 2 with an ink contg. a material made sticky when heated or humidified in a fixed condition and suitable for reflection, and the sheet 2 is bonded to an acrylate sheet 1, etc., with the formed reflecting pattern 3 as an adhesive. The light injected from the end face is projected into the pattern 3, irregularly reflected by a reflecting material in the pattern 3 and injected into the sheet, and most of the light component is projected from the front since the incident angle is large. Meanwhile, the light projected on the part except the pattern and transmitted through the acrylate sheet 1 is totally reflected as it is and transmitted, since the incident angle of the light is small and the refractive index of the air in contact with the sheet is smaller than that of the acrylate sheet 1.

Description

Detailed Description of the Invention

This invention relates to a light guide plate used for back lighting of a liquid crystal display device or the like.

[0001]

2. Description of the Related Art In a conventional light guide plate, a reflection pattern is directly printed on the back surface of an acrylic plate as shown in FIG. In the light guide plate, the light incident from the end surface of the plate has a refractive index of acrylic much higher than that of air, so the light is totally reflected on the inner wall surfaces of the front and back surfaces of the plate and does not go outside to the other end surface. By utilizing the fact that light is propagated, if a reflective layer is provided on the back surface, which is one of the reflective surfaces, with an appropriate pattern, light will be diffusely reflected where there is a pattern and irradiated to the front side, and where there is no The surface light source is obtained as if the light that was totally reflected and propagated, and as a result, the light incident from the end face is appropriately dispersed over the entire surface. In this case, the reflection pattern has often been adopted by directly forming an ink by mixing a powder of metal or the like, which is a material suitable for reflection, on an acrylic plate by screen printing.

[0002]

As described above, the method of directly forming a pattern on an acrylic plate by screen printing seems to be simple and mass-produced, but in reality, there are many problems in the process. The biggest problem is the lack of continuity. That is, the number of sheets that can be printed in one stroke is limited in screen printing, and the rest period is inevitable until the next stroke. In order to eliminate such a problem, for example, a roller transfer method or the like may be adopted, but when the object is an acrylic plate, a mass production effect cannot be expected so much due to the difficulty of handling it. Further, in the case of the above method, when a problem such as clogging of the screen occurs during the process, the acrylic plate becomes a defective product and causes great damage. In view of the problems of the above conventional method, the present invention proposes a light guide plate structure which is simple, excellent in mass productivity, and lower in cost.

[0003]

As a means for solving the above problems, in the present invention, a light guide plate is constructed by printing a reflection pattern on a thin sheet of plastic or the like and adhering it to an acrylic plate. It is a proposal. What is important in this case is that the reflection pattern itself adheres to the acrylic plate with adhesiveness.

[0004]

The operation of the present invention will be described with reference to the sectional view of FIG. The function of the light guide plate is exactly the same as that of the conventional light guide plate. The light incident from the end face is irradiated to the outside, that is, in the pattern from the plate by the adhesive having a refractive index higher than that of the acrylic because the pattern is in close contact with the acrylic in a part of the pattern, but is diffusely reflected by the reflective material in the pattern. It enters the plate again. At that time, most of the light components have a large incident angle, and thus are directly irradiated from the front surface.
On the other hand, the light propagating inside the acrylic plate, which is irradiated to a portion other than the pattern portion, has a small incident angle, and since the air in contact with the plate has a smaller refractive index than acrylic, it is totally reflected and propagates as it is. Since the plastic sheet on which the pattern is formed in advance is white, the light leaking from the acrylic plate is effectively applied to the front surface.

[0005]

1 is a perspective view showing one of the embodiments and FIG. 2 is a sectional view of the embodiment, and in terms of performance, the light leaking from the end portion of the conventional light guide plate is As shown in FIG. 3, the amount of leakage was large because the end face of the metallic frame body 6 provided outside was bent to form a reflecting face. Since it is glued, the leakage light is almost negligible. Further, since the sheet portion is a reflection plate that reflects leaked light and protects the reflection pattern and the back surface of the acrylic plate, a metallic frame body as in the past is not necessary.

[0010]

[Brief description of drawings]

FIG. 1 is a perspective view of an example showing a state in which a part of a sheet is peeled off.

FIG. 2 is a sectional view of an example.

FIG. 3 is a sectional view of a conventional lighting device including a light guide plate.

[Explanation of symbols]

 1 transparent acrylic plate 2 sheet 3 reflection pattern 4 light incident end 5 end reflection pattern 6 frame

Claims (1)

[Claims] 1. A light guide plate used for back lighting of a liquid crystal display device, etc., is made of a material having a back surface reflection pattern which is tacky when a constant condition such as heating or humidification is applied and is suitable for reflection. A light guide plate having a structure in which the contained ink is formed on a thin white plastic sheet in advance, and then the plastic sheet is adhered to an acrylic plate or the like using the formed reflection pattern as an adhesive.