JPH05203951A - Liquid crystal display element - Google Patents

Abstract

PURPOSE:To provide the liquid crystal display element with which a wide visual field is obtd. by dividing the element to plural regions by a simple structure. CONSTITUTION:This liquid crystal display element is constituted of a 1st substrate 11 which has plural pieces of orientation regions having arbitrary shapes and is applied with orientation regulating force so as to vary the directions by 180 deg. with the adjacent orientation regions from each other or the orientation regions adjacent via intermediate regions from each other, a 2nd substrate 12 which is applied with the orientation regulating force of a small pretilt angle uniformly over the entire surface of the substrate in the direction rotating +90 deg. or -90 deg. from the orientation regulating force of any of the orientation regions of the 1st substrate and a liquid crystal material which is clamped between the 1st substrate 11 and the 2nd substrate 12.

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 device,
In particular, it relates to a liquid crystal display device having a display image quality almost equal to that of a CRT.

[0002]

2. Description of the Related Art Currently, as a liquid crystal display device (LCD),
A TN (twisted nematic) type liquid crystal display element (TN-LCD) is known as a typical one.
The structure and characteristics of this element are well known.
P of "Liquid Crystal Device Handbook" (Nikkan Kogyo Shimbun)
329 et seq. Alignment treatment is important for LCDs including TN-LCDs, but regarding this, P241 of "Liquid Crystal Device Handbook" mentioned above is also relevant.
It is described below.

In the TN-LCD, while high contrast can be obtained, it has viewing angle dependency. As shown in FIG. 4, there is a drawback that the viewing angle dependency is particularly remarkable in the vertical direction when displaying halftone.

A conventional liquid crystal display device that solves the drawbacks of the TN type is disclosed in, for example, Japanese Patent Laid-Open No. 63-106624. FIG. 3 shows a schematic view of this conventional liquid crystal display device alignment method. As shown in FIG. 3 of this publication, an alignment direction treatment in which the directions of 180 ° in the regions I and II of both substrates are different is performed, thereby obtaining a wide viewing angle. That is, since the regions having different orientations of 180 ° are present adjacent to each other, when light is incident from an oblique direction inclined from the vertical direction with respect to the substrate, the respective regions compensate each other's optical characteristics. Fit. As a result, the viewing angle dependence is canceled by the regions having different alignment directions between the upper and lower substrates, and optical characteristics with little viewing angle dependence are obtained. Further, even in the case of gradation display, the regions having different alignment directions mutually compensate for the optical characteristics, so that gradation inversion hardly occurs.

[0005]

However, in this conventional liquid crystal display element, both substrates sandwiching the liquid crystal layer are divided and aligned, and the process of divided alignment and the process of aligning both substrates are complicated. Since the number of processes is increasing,
It is very difficult to manufacture at low cost and with good yield.

The object of the present invention is to provide the above-mentioned conventional TN-LC.
The object of the present invention is to eliminate the drawback that the viewing angle of D is narrow, and to provide at low cost a liquid crystal display element having a wide viewing angle almost equal to that of a CRT even in gradation display.

[0007]

A liquid crystal display element of the present invention has a plurality of alignment regions of arbitrary shape, and the alignment regions adjacent to each other or the alignment regions adjacent to each other via an intermediate region are 180 + 90 ° or −90 ° from the orientation control force direction of the first substrate to which the orientation control force is applied so that the direction is different, and the orientation region of any one of the first substrates.
In the rotated direction, the entire surface of the substrate is made uniform, and the second substrate is provided with an alignment regulating force with a small pretilt angle, and a liquid crystal substance sandwiched between the first substrate and the second substrate. .

[0008]

[Function] "180 ° in different directions" means exactly 180
It does not mean that they differ from each other, and it is sufficient that the directions differ by approximately 180 °. Further, “in the direction rotated by + 90 ° or −90 ° from the alignment regulating force direction of any of the alignment regions of the first substrate” does not mean strictly + 90 ° or −90 °. , About + 90 ° or −90 °.

[0009]

EXAMPLE A typical structure of a liquid crystal display device according to the present invention is shown in FIG. 1A is a plan view and FIG. 1B is a sectional view.

The first substrate 11 is divided into a plurality of orientation regions of arbitrary shape. Hereinafter, such an alignment process is referred to as a split alignment process. As a method for realizing this divisional alignment, it is practical to use a photoresist and limit the region to be rubbed. The entire surface of the second substrate 12 is rubbed uniformly.

In this way, the first substrate 1 which has been subjected to the split orientation treatment.
When 1 and the second substrate 12 subjected to uniform alignment treatment on the entire surface are combined, there is a problem whether the alignment treatment of the liquid crystal layer 7 is controlled by the alignment treatment of the first substrate or the second substrate. According to our experiments, by making the pretilt angle of the first substrate substantially equal to or larger than the pretilt angle of the second substrate, the alignment treatment of the first substrate causes the alignment of the liquid crystal layer to be dominant. And orientations different from each other by 180 ° were realized.

The method of manufacturing the first substrate 11 according to the present invention is as shown in FIG. In FIG. 2, as shown in (A), the polyimide-based alignment film 3 was applied on the transparent electrode 2 of the transparent substrate 1.

In this embodiment, glass is used for the transparent substrate and indium tin oxide (ITO) is used for the transparent electrode, but the present invention is not limited to this.

The first rubbing treatment is applied to the entire surface of the alignment film 3 (FIG. 2 (B)), the shielding material 6 is applied to the surface of the alignment film (FIG. 2 (C)), and partially removed. The area is shielded (FIG. 2D), and then 180 ° with the rubbing direction.
A rubbing process is performed in different directions (FIG. 2 (E)) to remove the shielding material 6, and the divided regions 4 and 5 are removed as shown in FIG. 2 (F).
The orientation control force in each direction was applied to. In this embodiment, the shielding material is photoresist.

On the second substrate 12, a polyimide-based alignment film 3 was formed on the transparent electrode 2, and the entire surface was uniformly rubbed.

The first substrate 11 manufactured by the above steps
The second substrate 12 and the rubbing direction between the substrates is 90 °.
Alternatively, the cells were superposed at −90 ° and bonded with an adhesive through a spherical spacer made of silica particles having a diameter of 5 μm to form a cell, and liquid crystal was injected into the cell. This liquid crystal material is a normal nematic liquid crystal in which the left chiral material is dissolved.

The liquid crystal display device thus obtained is
As shown in FIG. 1, two 1s corresponding to the divided areas 4 and 5 are formed.
A TN liquid crystal alignment having different 80 ° alignment directions was realized.
As a result, the wide viewing angle characteristics as shown in FIG. 5 were obtained by compensating the optical characteristics of these two regions. This viewing angle characteristic corresponds to the viewing angle characteristic of the lower visual field of a normal panel.

In the above embodiment, the pixel electrode and the divided region 4,
Although the positional relationship with No. 5 was not specified, almost the same wide viewing angle characteristics were obtained even if one pixel was divided into several areas or one pixel was made into one divided area. As described above, the method and pattern of the divisional alignment treatment are not limited to those in the above embodiment, and various patterns are possible.

In this embodiment, the thin film transistor (T
When applied to an active matrix LCD using FT) or a non-linear resistance, and further applied to a simple matrix LCD, a remarkable effect of improving the viewing angle was observed.

[0020]

According to the present invention, even if the alignment direction of the liquid crystal is changed depending on the strength of voltage application, optical compensation is performed within the device, so that not only the black and white display but also the result of FIG. As described above, it is possible to obtain a liquid crystal display element having a wide viewing field characteristic that does not depend on the viewing angle even at the time of gradation display, at low cost.

[Brief description of drawings]

FIG. 1 is a diagram schematically showing an example of a liquid crystal display element according to the present invention, where (A) is a plan view of a first substrate and (B) is a sectional view.

FIG. 2 is a cross-sectional view illustrating an example of a manufacturing process of a first substrate.

FIG. 3 is a diagram schematically showing a conventional liquid crystal display element.

FIG. 4 is a diagram showing measurement results of viewing angle dependence of transmittance in a lower visual field during gradation display in a conventional TN liquid crystal display device.

FIG. 5 is a diagram showing a measurement result of viewing angle dependence of transmittance in a lower visual field during gradation display of the liquid crystal display device according to the present invention.

[Explanation of symbols]

 1 Transparent Substrate 2 Transparent Electrode 3 Alignment Film 4, 5 Divided Area 6 Photoresist 7 Liquid Crystal Layer 11 First Substrate 12 Second Substrate

Claims (1)

[Claims] 1. A plurality of orientation regions having an arbitrary shape are provided, and the orientation regions adjacent to each other or the orientation regions adjacent to each other via an intermediate region are different in 180 ° direction,
Alignment regulation with a small pretilt angle uniformly over the entire surface in a direction rotated by + 90 ° or −90 ° from the orientation regulation force direction of the orientation regulation force of any one of the orientation regions of the first substrate and the orientation regulation force of the first substrate. A liquid crystal display device comprising a second substrate to which force is applied and a liquid crystal substance sandwiched between the first substrate and the second substrate.