JPH103008A - Light guiding plate of liquid crystal display panel, and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a light guiding plate which unnecessitates a lens sheet, reduces the production cost of a liquid crystal display panel and makes a screen of the liquid crystal display panel bright and easy to see and a manufacturing method thereof. SOLUTION: A lens face having a sectional form successively provided with a lot of minute hills having angular corners and the light guiding plate main body are integratedly formed on the surface to form the light transmission plate. In the manufacturing method of the light guiding plate, a lens face forming mold 8 in which a lot of V-shaped minute grooves are successively provided is disposed in a metallic mold 7 for injection molding for forming the light guiding plate of the liquid crystal display panel. The lens face forming mold 8 is heated to a temp. at or above the glass transition point of a raw material resin and, then, the molten raw material resin is injected in a cavity 9. Thus, the lens face and the light guiding plate main body are integrally formed on the surface.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light guide plate constituting a liquid crystal display panel built in a portable personal computer, a television, or the like.

[0002]

2. Description of the Related Art Conventionally, a light guide plate constituting a liquid crystal display panel.
Reference numeral 15 denotes a lens sheet 16 thereon, as shown in FIG.
The diffusion plate 17 was laminated, and the silk printing sheet 18 and the reflection plate 19 were laminated in that order under the diffusion plate 17. However, the lens sheet 16 is expensive, and a step of laminating the lens sheet 16 on the light guide plate 15 is required.

The lens surface 20 of the lens sheet 16 has a peak
It is known that the higher the height of 21 and the more square it is, the brighter the screen of the liquid crystal display panel becomes, making it easier to see,
Since the mold formed by the conventional molding method has poor transferability of the mold, as shown in FIG.
The height of 21 was limited to about 23 μ (micron), and only a round product could be manufactured. Therefore, in many cases, two lens sheets 16 are used in an overlapping manner.
The cost was high.

[0004]

SUMMARY OF THE INVENTION Therefore, the present invention
It is an object of the present invention to provide a light guide plate which can eliminate the need for a lens sheet, can reduce the manufacturing cost of a liquid crystal display panel, and can make the screen of the liquid crystal display panel bright and easy to see, and a method for manufacturing the same.

[0005]

In order to solve the above-mentioned problems, the present invention employs the following technical means.

The light guide plate of the liquid crystal display panel according to the present invention has a lens surface having a surface in which a large number of fine angular ridges having a cross section are continuously formed, and formed integrally with the light guide plate body.

According to the method of manufacturing a light guide plate of a liquid crystal display panel of the present invention, a large number of fine V-shaped grooves are continuously provided in an injection molding die for forming a light guide plate of a liquid crystal display panel. The lens surface molding die is provided, and the lens surface molding die is heated to a temperature equal to or higher than the glass transition point of the raw material resin, and the molten raw material resin is injected into the cavity, so that the lens surface is formed on the surface with the light guide plate body. They are formed integrally.

Further, the lens surface forming die may be heated at a high frequency. As a result of employing the above-described means, the present invention has the following operation.

The light guide plate of the liquid crystal display panel of the present invention has a lens surface formed integrally with the light guide plate main body on its surface, so that there is no need to stack lens sheets, and the cost is low. In addition, since the minute peaks on the lens surface are square, the screen of the liquid crystal display panel becomes bright.

According to the method for manufacturing a light guide plate of a liquid crystal display panel of the present invention, the temperature of the lens surface forming mold is higher than the glass transition point of the raw material resin, so that the flowability of the raw material resin is increased and the transferability is improved. Therefore, a lens surface having an angular peak higher than the peak of the lens surface of the conventional lens sheet can be formed.

Further, if the lens surface mold is heated by high frequency, the temperature near the surface of the lens surface mold can be raised to a temperature higher than the glass transition point in a short time.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described.
This will be described with reference to the drawings.

The light guide plate 1 of the liquid crystal display panel according to the present invention comprises:
The lens surface 3 is formed integrally with the light guide plate main body 4 on the surface thereof and has a shape in which a large number of fine angular ridges 2 are continuously formed in a cross section.

FIG. 1 is a perspective view showing an embodiment of a light guide plate 1 of a liquid crystal display panel according to the present invention. The light guide plate 1 is made of an acrylic resin, and has a gate surface 5 on the outer periphery of a two-dot chain line in the figure.
A use area 6 through which light constituting an image is transmitted is formed inside, and the surface has a height of 25 μm as shown in FIG.
The degree peaks 2 are formed such that the vertices are lined up every about 50 μm.

As described above, since the peak 2 of the lens surface 3 is higher than that of the conventional lens and is substantially perpendicular,
The liquid crystal display panel using the light guide plate 1 has a bright screen and is very easy to see.

Next, a method for manufacturing the light guide plate 1 will be described. The light guide plate 1 of this liquid crystal display panel is a mold 7 for injection molding for forming the light guide plate 1 of the liquid crystal display panel.
Is provided with a lens surface forming die 8 formed by connecting a number of fine V-shaped grooves, and the lens surface forming die 8 is heated at a high frequency to a temperature equal to or higher than the glass transition point of the raw material resin. It is formed by injecting a molten acrylic resin into the cavity 9.

FIG. 3 is a view showing a state where the mold 7 is opened before the acrylic resin is injected. The mold 7 includes a mold 7a on the left side of the figure that forms the light guide plate main body 4 and a mold 7b on the right side that forms the lens surface 3 on the surface of the light guide plate 1. The high-frequency oscillator 10 enters and exits the cavity 9 thereof. ing.

The lens mold 8 is provided on the right mold 7b. The lens surface forming die 8 is a rectangular plate having a thickness of 0.3 mm made by nickel electroforming, and is fitted into a 0.33 mm deep recess 11 formed in the right die 7b. Attached.

The lens surface forming die 8 is mounted with the bottom portion of the recess 11 as a mounting surface 12, and its surface is lower than the surface of the die 7b by 0.03 mm. The size of the lens surface forming die 8 is larger than the light guide plate 1 to be formed.
When forming the light guide plate 1 of 5 mm × 216 mm, 320 mm
It may be about 280 mm.

The high-frequency oscillator 10 is composed of an inductance coil, and is connected to the power supply 13 as shown in FIG. 3, and oscillates a high-frequency of 35 to 50 kHz at an output of 30 kW. The high frequency generated by the high frequency oscillator 10 is of type 7a,
An eddy current is generated in 7b, and the eddy current generates heat on the surfaces of the molds 7a and 7b.

In order to manufacture the light guide plate 1 using the mold 7, first, the mold 7 is heated by the high-frequency oscillator 10.
The heating of the mold 7 is performed until the surface of the lens surface forming mold 8 reaches a temperature higher than the glass transition point of the acrylic resin, for example, 180 ° C. or higher. According to the heating by the high frequency, a larger calorific value is obtained than in the case of heating by the electric heater, and it takes only about several seconds until the temperature becomes equal to or higher than the glass transition point.

Next, the high-frequency oscillator 10 is taken out, the two molds 7a and 7b are closed as shown in FIG. 4, and the surface of the lens surface molding die 8 is maintained at a temperature equal to or higher than the glass transition point. The molten acrylic resin is injected from the nozzle 14 into the cavity 9 and filled. Since the filled acrylic resin has exceeded the glass transition point for a while, it has extremely high fluidity and can reach the corner of the groove of the lens surface forming die 8. Therefore, the transferability is extremely excellent, and it is possible to form the ridges 2 and the grooves that are more angular than the ridges 21 of the conventional lens surface 20 in almost eight lens surface molding dies.

Then, the mold 7 is cooled. The mold 7 was heated at a high temperature equal to or higher than the glass transition point.
Since only the vicinity of the surface is heated, not the whole, cooling can be performed in a relatively short time. After that, the mold 7 is opened and the formed light guide plate 1 is taken out.

In the mold 7, since the lens surface forming die 8 provided on the right side die 7b is not integral with the die 7b, the lens surface forming die 8 can be removed. Therefore, even if the lens surface forming mold 8 is worn or deformed, the mold 7 is newly added.
Need not be manufactured, the lens surface molding die 8 is removed,
It only needs to be replaced with a new lens surface molding die 8.

The lens surface forming die 8 may be provided integrally with the die 7b.

[0026]

The light guide plate of the liquid crystal display panel according to the present invention comprises:
With the above-described configuration, the lens surface is formed integrally with the light guide plate body on the surface, and there is no need to stack lens sheets, so that the manufacturing cost of the liquid crystal display panel can be reduced, In addition, since the peak of the lens surface is high and angular, the screen of the liquid crystal display panel becomes bright and can be easily viewed.

According to the method of manufacturing a light guide plate for a liquid crystal display panel of the present invention, the lens surface molding die is set at a temperature equal to or higher than the glass transition point of the raw material resin to increase the fluidity of the raw material resin. The transferability of the light guide plate is extremely excellent, and the light guide plate, which has never existed before, can be manufactured.

[Brief description of the drawings]

FIG. 1 is a perspective view of a light guide plate of a liquid crystal display panel according to the present invention.

FIG. 2 is a partially omitted sectional view of a light guide plate of the liquid crystal display panel according to the present invention.

FIG. 3 is a cross-sectional view showing an open state of a mold for forming a light guide plate of a liquid crystal display panel according to the present invention.

FIG. 4 is a sectional view showing a closed state of a mold for forming a light guide plate of a liquid crystal display panel according to the present invention.

FIG. 5 is a perspective view showing a disassembled state of a light guide plate of a conventional liquid crystal display panel.

FIG. 6 is a partially omitted cross-sectional view of a light guide plate of a conventional liquid crystal display panel.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Light guide plate 2 Mountain 3 Lens surface 4 Light guide plate main body 7 Mold 8 Lens surface forming die 9 Cavity

Claims (3)

[Claims] 1. A light guide plate for a liquid crystal display panel, wherein a lens surface having a surface in which a number of fine peaks having a fine cross section are formed continuously is formed integrally with a light guide plate main body. 2. An injection molding die for forming a light guide plate of a liquid crystal display panel is provided with a lens surface molding die having a large number of minute V-shaped grooves continuously provided. A liquid crystal display characterized in that a lens surface is formed integrally with the light guide plate main body by heating the glass to a temperature equal to or higher than the glass transition point of the raw resin and injecting the molten raw resin into the cavity. Manufacturing method of light guide plate for panel. 3. The method for manufacturing a light guide plate of a liquid crystal display panel according to claim 2, wherein the lens surface forming die is heated at a high frequency.