JPH0580324A - Liquid crystal display element - Google Patents

Abstract

PURPOSE:To increase response speed and to improve display quality. CONSTITUTION:The twist angle of the STN type high-speed response liquid crystal material of a liquid crystal display cell 1 is set at 220 deg., the stretching axial angle of a lower phase plate 2 at 67 deg., the stretching axial angle of an upper phase plate 3 at 33 deg., the absorption axial angle of an upper polarizing plate 4 at 90 deg., the absorption axial angle of a lower polarizing plate 5 at 165 deg., the retardation value DELTAn.d of the liquid crystal display cell 1 at 860nm, and the retardation values DELTAn.d of the lower phase plate 2 and the upper phase plate 3 at 390nm, respectively.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an STN type phase plate type black and white liquid crystal display device.

[0002]

2. Description of the Related Art A conventional STN type phase plate type black-and-white liquid crystal display element has two phase plates and has a retardation value Δn · d of a liquid crystal display cell, that is, a refractive index anisotropy Δn of liquid crystal. The product with the layer thickness d is 775 nm, and the retardation value Δn · d of one phase plate is 400 nm.

In such a liquid crystal display device, the response speed is very slow, and the total time required for rising and falling is about 500 ms. When the pointer is moved at high speed by mouse operation, the pointer disappears. There are problems such as being lost.

Therefore, it is considered to use a high-speed response liquid crystal material as the liquid crystal material of the liquid crystal display cell.

As a device related to this type of device, there is one described in Japanese Patent Laid-Open No. 64-51900.

[0006]

However, when a high-speed response liquid crystal material is used as the liquid crystal material of the liquid crystal display cell, the brightness and contrast ratio are low. For example, the brightness when on is 35 cd and the contrast ratio is 5 to 6. In addition, since the viewing angle is small, the display quality is not good.

The present invention has been made to solve the above problems, and an object of the present invention is to provide a liquid crystal display device having a high response speed and good display quality.

[0008]

To achieve this object, in the present invention, the twist angle is 200 to 300.
A liquid crystal display cell having a STN type fast response liquid crystal material,
In a monochrome display liquid crystal display device having a lower phase plate, an upper phase plate, an upper plate polarizing plate, and a lower plate polarizing plate, the stretching axis angle of the lower phase plate is 62 to 72 degrees, and the upper phase is The stretching axis angle of the plate is 28 to 38 degrees, the absorption axis angle of the upper plate polarizing plate is 85 to 95 degrees, the absorption axis angle of the lower plate polarizing plate is 160 to 170 degrees, and the retardation of the liquid crystal display cell is set. The value is set to 800 to 950 nm, and the value obtained by subtracting the sum of the retardation value of the lower phase plate and the retardation value of the upper phase plate from the retardation value of the liquid crystal display cell is set to 90 nm or less.

[0009]

In this liquid crystal display element, even if a fast response liquid crystal material is used as the liquid crystal material of the liquid crystal display cell, the brightness,
High contrast ratio and wide viewing angle.

[0010]

1 is a front view showing a liquid crystal display element according to the present invention, and FIG. 2 is a plan view showing the liquid crystal display element shown in FIG. In the figure, 1 is a liquid crystal display cell having a STN type fast response liquid crystal material, 2 is a lower phase plate provided on the upper plate side of the liquid crystal display cell 1, and 3 is an upper phase plate provided on the lower phase plate 2. Reference numeral 4 denotes an upper plate polarizing plate provided on the upper phase plate 3, and 5 denotes a lower plate polarizing plate provided on the lower plate side of the liquid crystal display cell 1, which are arranged on the liquid crystal molecule distribution axes A and B of the liquid crystal display cell 1. The angle formed, that is, the twist angle is 220 degrees, the angle formed by the extension axis C of the lower phase plate 2 and the line that bisects the twist angle, that is, the center line G, that is, the extension axis angle c of the lower phase plate 2 is 67 degrees, and The angle formed by the extension axis D of the phase plate 3 and the center line G, that is, the extension axis angle d of the upper phase plate 3 is 33 degrees, and the angle formed by the absorption axis E of the upper plate polarizer 4 and the center line G, that is, the upper plate polarization. The absorption axis angle e of the plate 4 is 90 degrees, and the angle formed between the absorption axis F of the lower plate polarizing plate 5 and the center line G, that is, the lower plate polarizing plate 5 A Osamujiku angle f is 165 degrees, the retardation value [Delta] n · d of the liquid crystal display cell 1 is 860 nm, the lower phase plate 2, the retardation value [Delta] n · d of the upper phase plate 3 are each 390 nm.

In this liquid crystal display element, even if a fast response liquid crystal material is used as the liquid crystal material of the liquid crystal display cell 1,
The brightness and contrast ratio are high, for example, the brightness when turned on is 50 cd, the contrast ratio is 12, and the viewing angle is large, so that the response speed is fast, and the total time required for rising and falling is about 280 to 280, for example. 300
ms, and the display quality is good.

In the above embodiment, the twist angle of the liquid crystal display cell 1 is 220 degrees, but the liquid crystal display cell 1 has a twist angle of 220 degrees.
The twist angle may be 200 to 300 degrees. Also,
In the above-mentioned embodiment, the stretching axis angle c of the lower phase plate 2 is 67 degrees, the stretching axis angle d of the upper phase plate 3 is 33 degrees, the absorption axis angle e of the upper polarizing plate 4 is 90 degrees, and the lower polarizing plate is polarized. Although the absorption axis angle f of the plate 5 is 165 degrees, the stretching axis angle c of the lower phase plate 2 is 62 to 72 degrees, and the stretching axis angle d of the upper phase plate 3 is 28 degrees.
Up to 38 degrees, the absorption axis angle e of the upper polarizing plate 4 is 85 to 95
And the absorption axis angle f of the lower plate polarizing plate 5 may be 160 to 170 degrees. Further, in the above-mentioned embodiment, the retardation value Δn · d of the liquid crystal display cell 1 is set to 860 nm, but the retardation value Δn · d of the liquid crystal display cell 1 is set to 80.
It may be 0 to 950 nm. In addition, in the above-described embodiment, the retardation values Δn · d of the lower phase plate 2 and the upper phase plate 3 are set to 390 nm, respectively, but the retardation value Δn · d of the liquid crystal display cell 1 is changed to The value obtained by subtracting the total value of d and the retardation value Δn · d of the upper phase plate 3 may be 90 nm or less.

[0013]

As described above, in the liquid crystal display element according to the present invention, even if a fast response liquid crystal material is used as the liquid crystal material of the liquid crystal display cell, the brightness and contrast ratio are high and the viewing angle is large. Therefore, the response speed is fast and the display quality is good. As described above, the effect of the present invention is remarkable.

[Brief description of drawings]

FIG. 1 is a front view showing a liquid crystal display element according to the present invention.

FIG. 2 is a plan view showing the liquid crystal display element shown in FIG.

[Explanation of symbols]

 1 ... Liquid crystal display cell 2 ... Lower phase plate 3 ... Upper phase plate 4 ... Upper plate polarizing plate 5 ... Lower plate polarizing plate

Claims (1)

[Claims] 1. A liquid crystal display cell having a STN type high-speed response liquid crystal material having a twist angle of 200 to 300 degrees, a lower phase plate, an upper phase plate, an upper polarizing plate, and a lower polarizing plate. In the monochrome display liquid crystal display device, the stretching axis angle of the lower phase plate is 62 to 72 degrees, the stretching axis angle of the upper phase plate is 28 to 38 degrees, and the absorption axis angle of the upper polarizing plate is 85 to 85 degrees. The angle of the absorption axis of the lower polarizing plate is set to 95 degrees.
A value obtained by subtracting the total value of the retardation value of the lower phase plate and the retardation value of the upper phase plate from the retardation value of the liquid crystal display cell at 60 to 170 degrees, the retardation value of the liquid crystal display cell at 800 to 950 nm. Is 90 nm or less, a liquid crystal display device.