JPH049818A - Liquid crystal display panel - Google Patents

Abstract

PURPOSE:To recognize a display of high quality at a wide angle by limiting the direction of light which is made incident on liquid crystal and properly controlling the transmissivity, and providing a polarizing element and a light scattering part right and scattering projection light right after the light passes through a liquid crystal layer. CONSTITUTION:Two light control films 2A and 2B are stuck having their axes of light absorption orthogonally to each other to limit the angle of incidence of a light beam which is made incident on a polarizing direction in two dimensions, and the light beam whose incidence angle is limited is made incident on the polarizing plate 3 and passed through a light-source side glass substrate 4. Then the phase state is controlled by the liquid crystal layer 7 and transmissivity modulation is imposed by a light source and a striped conductor film polarizing element 9 as a polarizing element corresponding to the substrate on the opposite side. This light beam is scattered at a wide angle in the border area between the glass substrate 5 as the light scattering part and a surface- flattened dielectric film 10. Consequently, the display panel which has good display quality at a wide field angle is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a liquid crystal display panel, and particularly to the structure of a liquid crystal display panel with a wide viewing angle.

[Conventional technology]

Conventionally, as a measure to reduce the viewing angle dependence of twisted nematic liquid crystal display panels, the birefringence Δn of the liquid crystal material has been
Attempts have been made to develop materials to make the size as small as possible and to improve the characteristics using a phase film as described below (IEICE technical research report EID89-94). Figure 5 is a diagram showing a liquid crystal display panel with improved viewing angle characteristics using a phase film, broken down into component parts.The retardation value of the phase film is 3QQnm, and the material is polycarbonate. . When the optical axes 18A and 18B of the two phase films 16A and 16B are orthogonal to each other, changes in the phase of the mutually orthogonal vibration components are canceled out for the vertically incident light that passes through the polarizing plate 15A and enters, resulting in a phase difference. However, for obliquely incident light, there is a phase difference between before it enters the two phase films and after it passes through it, and if this is an appropriate value, T
There is an effect of compensating for the phase shift with the vertically incident light that occurs when passing through the N liquid crystal layer 17, and as a result, the transmittance characteristics of the obliquely incident light after passing through the polarizing plate 15B approach those of the vertically incident light to some extent. .

Therefore, viewing angle characteristics are improved.

[Problem to be solved by the invention]

Display in each pixel of a liquid crystal display panel is performed by controlling light transmittance in accordance with the display data of that pixel.

Here, if the above-mentioned phase film can bring the light incident on the pixel from various directions into the same phase state as the vertically incident light, a liquid crystal display panel with a wide viewing angle can be realized. However, since the phase characteristics of these light rays differ greatly depending on the angle of incidence, it is theoretically impossible to correct this with a phase film with high precision and bring the phase to the same phase as the vertically incident light.

An object of the present invention is to provide a configuration of a wide viewing angle display panel that eliminates the problems that inevitably occur when controlling light rays having various incident angles.

[Means to solve the problem]

In order to achieve the above object, the liquid crystal display panel of the present invention has the following features:
In a transmissive liquid crystal display panel in which a liquid crystal layer is sandwiched between two substrates and polarizing elements are provided on both sides of the liquid crystal layer, the angle of incidence of light entering the liquid crystal layer is limited between the substrate on the light source side and the light source. The present invention is characterized in that an incident angle limiting element is provided between the liquid crystal layer and the other substrate, and a polarizing element corresponding to the substrate side and a light scattering section for scattering polarized light are provided between the liquid crystal layer and the other substrate.

[Effect]

The wide viewing angle property of the liquid crystal display panel of the present invention will be explained below based on the light passage process. Of the light emitted from the light source, only the light rays perpendicular to the liquid crystal display panel and the light rays having a direction close to the perpendicular to the liquid crystal display panel pass through the incident angle limiting element. Thereafter, the light is polarized by a polarizing plate, which is a polarizing element corresponding to the substrate on the light source side, and its phase is modulated in the liquid crystal layer according to display data. Here, regarding the incident light, only light in directions within a certain limit passes through the liquid crystal layer, so each light beam undergoes equal modulation.

The modulated light is polarized with high precision by a polarizing element corresponding to the substrate on the opposite side of the light source, and becomes light with desired transmittance characteristics. Since there is a light scattering section immediately after that, the light is scattered over a wide angle, allowing display with wide viewing angle characteristics. That is, since only light whose incident angle is limited enters the liquid crystal layer, it is uniformly modulated in the liquid crystal layer. Since this light is scattered so that it can be recognized from a wide angle, there is no problem like when using a phase film, and it can be viewed from any angle in the same display state as in the vertical direction.

〔Example〕

Embodiments of the present invention will be described below based on the drawings.

FIG. 1 is a structural diagram showing an example of a liquid crystal display panel of the present invention. A light beam 11 emitted from a light source 1 enters two light control films 2B, which are incident angle limiting elements. The structure of this film is shown in Figure 2.
1 and a light absorption layer 22, light rays with a large incident angle are absorbed by this light absorption layer and cannot pass through. Therefore, the light ray 23 having a wide range of incident angles becomes a light ray 24 having a limited output angle after passing through the light control film. In this example, a film made by 3M Company that limits the angle to ±6° was used. In FIG. 1, two light control films 2B are pasted together with their light absorption axes perpendicular to each other to limit the angle of incidence of light rays incident on the polarizing plate in a two-dimensional direction. The light beam whose incident angle is limited enters the polarizing plate 6 and further passes through the light source side glass substrate 4. After this, the phase state is controlled in the liquid crystal layer 7,
The light beam is modulated in transmittance by a striped conductive wire film polarizing element 9, which is a polarizing element corresponding to the substrate on the opposite side of the light source. This light beam is scattered at a wide angle in the boundary area between the glass substrate 5 and the surface flattening dielectric film 10, which is a light scattering portion. ITO electrode 6B on the side opposite to the light source, dielectric insulating film 8, conductive am polarizing element 9, surface flattening dielectric film 10
The glass substrate 5 with a diffusion function is integrated, and an example of the manufacturing process is shown in FIG. First, as shown in (a-1,), a surface flattened dielectric film 10 is placed on a glass substrate 5 which has a diffusion function by randomly forming irregularities on the surface.
Attach. The refractive index of this film is different from that of glass. In order to cause light scattering, the microlenses 14 may be configured in a matrix as shown in (a-2) to utilize light refraction. Next, a striped conductive line film polarizing element 9 is formed on the surface planarized dielectric film. Figure 4 shows a view from above, and the width of the conductive line hatched using excimer laser photography was 0.2
μm, and the line spacing is 0.2 μm. When configured with this value, a highly accurate photometric element whose absorption axis is in the longitudinal direction of the conductive wire film is obtained. Aluminum or the like is used for the conductive wire film. In order to insulate the upper side of this conductive wire film from the electrode, (C)
The dielectric insulating film 8 is constructed as shown in FIG. After that (d)
Attach the ITO electrode 6B as shown in FIG. In the configuration of the present invention, a light scattering part is provided immediately behind the conductive wire film 9, but since the angle of the light beam passing through the light control film 2 is ±6°, the surface flattening dielectric film 10 The thickness should be as thin as possible. With the configuration shown in FIG. 1, it was possible to obtain a liquid crystal display panel with good display quality over a wide viewing angle.

〔Effect of the invention〕

According to the wide viewing angle liquid crystal display panel of the present invention, the direction of light entering the liquid crystal is restricted, the transmittance is controlled more appropriately, and a polarizing element and a light scattering part are provided immediately after passing through the liquid crystal layer to emit light. Since the incoming light is scattered, high-quality display can be recognized from a wide angle.

[Brief explanation of drawings]

Fig. 1 is a structural diagram showing the basic configuration of the present invention, Fig. 2 is a structural diagram of a light control film, Fig. 3 is a process diagram for configuring an element on a glass substrate on the light emission side, and Fig. 4 is a structural diagram showing the basic configuration of the present invention. FIG. 5 is a plan view of a polarizing element using a conductive line film, and is a diagram showing the constituent elements of a conventional liquid crystal display panel. 1...Light source, 2A, 2B...Light control film,
3...Polarizing plate, 4.5...Glass substrate, 6A, 6B...ITO electrode, 7...Liquid crystal layer, 8...・Dielectric insulating film, 9... Conductive wire film polarizing element, 10... Surface flattening dielectric film, 11... Light beam, 14... Microlens , 21... Light transmitting film, 22... Light absorbing film. m1 figure 2 figure 3 figure 1 m figure 4 figure 5

Claims (1)

[Claims] In a liquid crystal display panel that has a liquid crystal layer sandwiched between two substrates, has polarizing elements on both sides of the liquid crystal layer, and transmits and modulates light from a light source, the liquid crystal layer is provided between the light source and the substrate on the light source side. An incident angle limiting element is provided to limit the incident angle of light incident on the liquid crystal layer, and the polarizing element corresponding to the substrate side and a light scattering part for scattering the polarized light are provided between the liquid crystal layer and the other substrate. A liquid crystal display panel characterized by: