JPS6255624A - Liquid crystal display device - Google Patents

Abstract

PURPOSE:To enlarge a visual field angle of a liquid crystal display, and to improve the visibility of a panel display by forming at least a light scattering layer of a thin film to a polarizing plate side of a front substrate, or placing additionally a high refracting plate having an equal effect to the light spattering layer by making it adhere closely. CONSTITUTION:On a back light side substrate 2 of a panel substrate, an opposed electrode 4 is placed, also a TFT element 18 for a switching control of the electrode 4 is placed, and the surface side of the electrode 4 and the element 18 is covered with an insulating oriented film 17 to a liquid crystal layer 6. As for a glass substrate 1 of the panel front side, an R, G and B color filter forming layer 12, a transparent electrode 3, and the oriented film 17 are attached to the inner surface side, and to a front substrate 1, a polarizing plate 7 is made contacted and stuck, and constitutes a part of a liquid crystal shutter mechanism together with a polarizing plate 8 of a back substrate side. On the surface of the polarizing plate 7, a light spattering layer 10 having a low refractive index is formed as a thin film. It is used for scattering a display light corresponding to a liquid crystal cell coming out of the polarizing plate 7, in all the directions, and formed by sticking a light transmissive paint which has dispersed a metallic oxide fine particle into, for instance, an acryl compound resin.

Description

[Detailed Description of the Invention] [Summary] A liquid crystal panel configuration that improves the visibility of panel display by providing a visible light scattering layer that expands the viewing angle of 9 displays in a conventional liquid crystal display panel that constitutes a matrix electrode, for example. This is a presentation of the method.

[Industrial application field]

The present invention relates to a liquid crystal display device.

Liquid crystal displays use a system in which the alignment direction of liquid crystal molecules forming elongated chain molecules becomes optically transparent or opaque depending on the presence or absence of an electric field applied to an electrode.

There are various types of liquid crystals, including nematic, cholesteric, and smectic, which differ in the forces that act between aligned molecules.

The display panel of the present invention is a twisted nematic (Tw) display panel.
This was done in response to a request to improve the conventional narrow viewing angle of ISTED Nematic (abbreviated as TN) type liquid crystal display panels, etc., and the objective is to realize a panel display with a wide viewing angle and easy visibility.

[Conventional technology]

FIG. 2 is a schematic cross-sectional view of a liquid crystal display panel called a light transmission type, showing the driving principle of the panel.

A transparent electrode 3 and a counter electrode 4 are formed on the inside of the glass substrates 1 and 2, which are parallel flat plates, facing each other with a liquid crystal layer 6 of a very small thickness interposed therebetween. It is formed.

A separator 5 made of Mylar film with a thickness of about 10 μm is inserted between the substrates 1 and 2, and the gap between the inserted substrates is filled with liquid crystal.

In the figure, reference numerals 7 and 8 denote polarizing plates arranged outside the glass substrate, the directions of polarization of which are orthogonal to each other.

However, the polarized light incident on the liquid crystal through the polarizing plate 8 is
Since the light is rotated by 90 degrees by the TN type liquid crystal layer 6, the light passes through the other polarizing plate 7 and the panel enters a light transmitting state.

On the other hand, when a voltage is applied between each of the R, G, and B electrodes 3 and the counter electrode 4 of the set shown in FIG. This results in a dark pattern.

That is, in the liquid crystal display, a pattern is displayed by driving the cells sandwiched between the transparent electrode 3 and the counter electrode 4 in a matrix configuration.

[Problem that the invention seeks to solve]

The TN type liquid crystal display panel has advantages such as it is easy to form a large number of cell electrodes in a matrix structure when forming the panel, and it is also possible to arrange thin film transistors (TPTs, switching elements) made of amorphous silicon to drive the cells. However, since polarizing plates 7 and 8 are used,
A disadvantage of conventional display panels, such as CI'IT display devices, is that the viewing angle of the panel display is narrower.

Furthermore, as a similar display panel, a color display device has been developed that uses a bank light on the back side of the panel and uses this and a liquid crystal light shutter mechanism to control light transmission or non-transmission. As long as the device is used, the problem of the narrow viewing angle of the panel display remains.

[Means for solving problems]

Figure 2 is a cross-sectional view of a cell structure as an embodiment of the liquid crystal display device of the present invention, and Figure 5 is a light transmission type liquid crystal display panel that performs display using the bank light provided on the back side of the panel.

The present invention is a liquid crystal display device in which a thin light scattering layer 10 is formed on at least the polarizing plate 7 side of the front substrate 1, or a high refractive plate having the same effect as the light scattering layer is closely juxtaposed.

Further, a liquid crystal display device is provided in which a protective layer 11 for the light scattering layer, which is thinner than the front substrate 1, is formed on the surface of the thin film light scattering layer 10.

[For production]

Conventionally, the thin film light scattering layer 10 scatters the emitted light corresponding to the display pixels emitted from the polarizing plate 7 in all directions.
This has the effect of enlarging the narrow display viewing angle in a limited direction just in front of the polarizing plate 7.

Further, by making the protective layer 11 thinner than that of the front substrate, it is possible to eliminate the display from being recessed with respect to the display pixels.

〔Example〕

FIG. 1 is a sectional view showing a cell structure of a liquid crystal display filled with a TN type liquid crystal.

In the figure, the same panel components used in the description of the conventional panel structure j1 are given the same reference numerals.

Further, arrows 20 and 21 in the figure indicate the backlight irradiation direction and the viewing direction of the display pattern on the front side of the panel, respectively.

A counter electrode 4 is provided on the backlight side substrate 2 of the illustrated panel substrate.
are arranged, and a TPT element 18 for controlling switching of the electrode 4 is arranged.

The surface sides of the electrode 4 and the element 18 are insulatively oriented with respect to the liquid crystal layer 6 If! 17 is deposited.

The glass substrate 1 on the front side of the panel has R and G on the inner side.

The B color filter forming layer 12, the transparent electrode 3, and the above-mentioned alignment film 17 are deposited. A polarizing plate 7 is closely adhered to the front substrate 1, and forms part of a liquid crystal shutter mechanism together with the polarizing plate 8 on the rear substrate side.

Furthermore, a thin film of the light scattering layer 10 having a low refractive index according to the present invention is formed on the surface of the polarizing plate 70. This scatters the display light corresponding to the liquid crystal cell emitted from the polarizing plate 7 in all directions.1 For example, it is coated with a light-transmissive paint in which fine metal oxide particles are dispersed in acrylic resin to a thickness of several micrometers to several tens of micrometers. It was formed by wearing it.

In this way, the display viewing angle in a certain limited direction immediately in front of the conventional polarizing plate 7 is expanded.

However, instead of the above-mentioned light-transmitting paint, it is also possible to roughen the surface of a high refractive index material and adhere a thin plate having a thickness of several μm to several tens of μm.

The layer 11 on the display surface side of the front substrate 1 is a protective layer that protects the function of the light scattering layer 10. Attaching the protective layer 11 is effective in protecting the display panel from mechanical scratches and protecting the light scattering layer from contamination.In addition, in order to improve the visibility of the display panel, the thickness of the protective layer 11 is made sufficiently thicker than the front substrate. It is effective for wide-angle viewing and clear display of the light scattering layer of the liquid crystal display cell in the substrate by making it thin.

Note that the color filter formation Ji12 is composed of red (R), green (
It is composed of three primary colors, G) and blue (B), and can be displayed in any color including white by controlling the orientation of the TN type liquid crystal layer 6 using the transparent electrode 4 and the facing electrode 3. .

In the above embodiments, a TPT-driven TN type liquid crystal display device was mainly described, but it goes without saying that the present invention can also be applied to a guest-host type liquid crystal display device or a normal simple matrix type liquid crystal display device.

〔Effect of the invention〕

As is clear from the above description, according to the liquid crystal display device of the present invention incorporating a light scattering plate or an equivalent high refractive plate, the viewing angle of the liquid crystal display can be expanded.

This has the remarkable effect of improving the visibility of the panel display.

[Brief explanation of drawings]

FIG. 1 is a sectional view of an embodiment of the liquid crystal display device of the present invention. FIG. 2 is a schematic panel sectional view of a conventional liquid crystal display panel drive. In the figure, 1 and 2 are substrates, and 7 and 8 are polarizing plates.

Claims (2)

[Claims] (1) A liquid crystal display device, which is a light transmission type liquid crystal display panel, characterized in that a light scattering layer (10) is formed at least on the front substrate (1) side. (2) Protective layer (11) on the surface of the thin light scattering layer (10)
2. The liquid crystal display device according to claim 1, wherein the liquid crystal display device is formed with:.