JPH11167109A - Liquid crystal display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the function of light reflection of a half-transmissive reflecting means as to a half-transmission type liquid crystal display device. SOLUTION: The liquid crystal display device which is equipped with a back light unit 2 arranged on the back of the liquid crystal display panel and having a half-transmissive reflecting means formed on a polarizing plate 3 formed on the back-light side surface of the liquid crystal display panel is constituted by using a metallic film 5 having many holes 5a bored as the half- transmissive reflecting means.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display, and more particularly, to a liquid crystal display called a transflective type.

[0002]

2. Description of the Related Art A liquid crystal display device called a transflective type is provided with a backlight on the surface (rear surface) of the liquid crystal display panel opposite to the observation side. Is configured to reflect an ambient light without recognizing an image and to recognize an image.

The liquid crystal display panel itself has only a function of controlling the amount of transmitted light in a large number of pixels constituting the display section.

[0004] For this reason, a backlight is provided on the back surface of the liquid crystal display panel, and the light of the backlight is transmitted to the viewer side through the liquid crystal display panel, or a reflection film is formed on the back surface of the liquid crystal display panel. After the ambient light is made incident on the reflective film, the light must be reflected toward the observer via the liquid crystal display panel.

[0005] The transflective liquid crystal display device has a configuration in which both of the above configurations are incorporated, and a transflective reflecting means is formed on the upper surface of the polarizing plate on the backlight side of the liquid crystal display panel. By means, the light of the backlight can be semi-transmitted to the liquid crystal display panel side, and the surrounding light can be reflected to the liquid crystal display panel side after entering.

Specifically, this means is to apply a semi-transparent film to the surface of a polarizing plate attached to the back surface of a liquid crystal display panel via an adhesive mixed with a large number of light diffusing materials. It is configured.

Here, the light diffusing material is provided to make the light transmitted through the light transmitting film and the light reflected from the light transmitting film uniform.

[0008]

However, in the liquid crystal display device configured as described above, the improvement of the reflection function of the transflective film is not limited, and the background of the image becomes dark even if various measures are taken. The problem has been pointed out.

The present invention has been made in view of such circumstances, and an object of the present invention is to provide a liquid crystal display device capable of improving the function of light reflection.

[0010]

SUMMARY OF THE INVENTION Among the inventions disclosed in the present application, the outline of a representative one will be briefly described.
It is as follows. That is, a liquid crystal display panel, and a backlight disposed on the back surface of the liquid crystal display panel, wherein a semi-transmissive reflecting means is formed on the upper surface of a polarizing plate formed on the surface of the liquid crystal display panel on the backlight side. In the liquid crystal display device described above, the semi-transmissive reflecting means is a metal film provided with a large number of holes.

The liquid crystal display device thus configured uses a metal film having excellent reflection efficiency as a reflection means, and has a large number of holes for providing a semi-transmission function.

[0012] From this, it is possible to easily cope with a case where the function of reflection is to be further improved by reducing the size or the number of holes formed therein.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the liquid crystal display device according to the present invention will be described below with reference to the drawings. FIG. 1A is a cross-sectional view of a liquid crystal display device including a liquid crystal display panel 1 and a backlight unit 2 disposed on the back of the liquid crystal display panel 1.

The liquid crystal display panel 2 is constituted by a pair of transparent substrates 1a and 1b which are arranged to face each other with a liquid crystal therebetween as an envelope. An electronic circuit for controlling the amount of light transmitted through the liquid crystal is formed for each of a large number of pixels constituting the display unit.

[0015] A polarizing plate is attached to the surface of each transparent substrate opposite to the liquid crystal.

The pixel structure of the above-mentioned liquid crystal display panel is not particularly limited, and may be, for example, a vertical electric field type or a horizontal electric field type. Nor.

Here, in the vertical electric field method, a pixel electrode is formed on each of the transparent substrates facing each other, and an electric field is generated in the direction of these electrodes (perpendicular to the transparent substrate) to reduce the light transmittance of the liquid crystal. The horizontal electric field method is to form a display electrode and a counter electrode on one side of an opposing transparent substrate, and generate an electric field in the direction of these electrodes (horizontal direction to the transparent substrate). This is a method of controlling the light transmittance of the liquid crystal at least.

As shown in FIG. 1B, of the polarizing plates formed on the liquid crystal display panel 1, the upper surface of the polarizing plate 3 formed on the surface on the side of the backlight unit 2 has a semi-transmissive surface. Is formed.

The transflective reflecting means includes a metal film 5 attached to the polarizing plate 3 via an adhesive 4 and a metal film 5
And a transparent polyester-based film 6 which is adhered and covered.

The metal film 5 is made of, for example, an aluminum film or a silver film. As shown in FIG. 2, the surface of the metal film 5 has a hole 5a having a diameter of, for example, 2 to 50 microns.
Are formed in the range of 10 to 1000 / cm ² .
Such holes can be formed, for example, by using a selective etching method using a known photolithography technique.

The metal film 5 having such a structure is formed as shown in FIG.
As shown in (b), the light A incident from one surface (observation side) can be reflected by a portion where the hole 5a is not formed, and the other surface (backlight unit 2 side). Can be transmitted through the portion where the hole 5a is formed,
It has a function as a transflective reflecting means.

In this case, when the reflectance is to be improved, it can be easily dealt with by reducing the size or the number of holes formed therein.

When the aluminum film is selected as the metal film 5, for example, the polyester film 6 is formed for the purpose of preventing the oxidation because the surface is easily oxidized. For this reason, it goes without saying that when a metal film having no fear of oxidation is selected, such an antioxidant film is not particularly required.

The backlight unit 2 includes a transparent light guide plate 2a having substantially the same size as the liquid crystal display panel 1;
A cold cathode ray tube 2b disposed on an end surface of one side of the light guide plate 2a; and a light guide plate 2a for transmitting light from the cold cathode ray tube 2b.
And a reflecting plate 2c for reflecting light toward the end face.

Light from the cold cathode ray tube 2b guided into the light guide plate 2a is reflected in the light guide plate 2a and emitted from the surface facing the liquid crystal display panel 1.

FIG. 3 shows a conventional semi-transmissive reflecting means, in which a large number of light diffusing materials 7 are mixed into the surface of the polarizing plate 3 attached to the back surface of the liquid crystal display panel 1. The translucent film 9 is adhered via the adhesive 8.

As described above, in this case, the semi-transmissive film 9 has a disadvantage that the background of the image is darkened even if various measures are taken, because the improvement of the reflection function is limited.

As is apparent from the above description, according to the liquid crystal display device of the present invention, a metal film having excellent reflection efficiency is used as the reflection means, and a large number of holes are formed in order to have a semi-transmission function. It is provided.

From this fact, it is possible to easily cope with a case where the reflection function is further improved by reducing the size or the number of holes formed therein.

[0030]

As is apparent from the above description,
According to the transflective liquid crystal display device of the present invention, the function of light reflection in the transflective reflecting means can be improved.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing one embodiment of a liquid crystal display device according to the present invention.

FIG. 2 is a plan view showing one embodiment of a metal film used in the liquid crystal display device according to the present invention.

FIG. 3 is a configuration diagram showing an example of a semi-transmissive reflection unit of a conventional liquid crystal display device.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Liquid crystal display panel, 1b ... Transparent substrate, 3 ... Polarizing plate, 4
... adhesive, 5 ... metal plate, 5a ... holes, 6 ... polyester film.

Claims (3)

[Claims] 1. A liquid crystal display panel, and a backlight disposed on the back side of the liquid crystal display panel, and a semi-transmissive reflecting means on an upper surface of a polarizing plate formed on a surface of the liquid crystal display panel on a backlight side. Wherein the semi-transmissive reflecting means is a metal film provided with a large number of holes. 2. The liquid crystal display device according to claim 1, wherein the large number of holes have a diameter of 2 to 50 microns and are provided at 10 to 1000 holes / cm ² . 3. The liquid crystal display device according to claim 1, wherein a transparent antioxidant film is formed on the surface of the metal provided with a large number of holes.