JPH0815714A - Liquid crystal display element - Google Patents

Abstract

PURPOSE:To obtain a liquid crystal display element of a wide visual angle with simple constitution by providing at least either of the electrodes formed on one substrate or on another substrate with apertures from which conductors are removed. CONSTITUTION:This liquid crystal display element has the one substrate 1 formed with the electrodes 3 consisting of the conductors, the other substrate 2 formed with the electrodes 3 consisting of the conductors facing the electrodes 3 of the one substrate 1 and liquid crystals 11 sealed between both substrates 1 and 2. The apertures from which the conductors are removed are formed on at least either of the electrodes 3 formed on the one substrate 1 or the electrodes 7 formed on the other substrate 2. The electric fields between the electrodes 3, 7 facing each other are made non-parallel by these apertures and the orientation states of the liquid crystal molecules in the respective pixels are not made uniform and vary in the respective parts when voltage is impressed between the electrodes 3, 7 facing each other. Namely, the plural domains varying in the orientation states of the liquid crystal molecules are formed within the respective pixels, by which 1 visual field angle of the liquid crystal display element is widened.

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, and more particularly to a liquid crystal display device having a wide viewing angle.

[0002]

2. Description of the Related Art An active matrix type liquid crystal display device includes a pixel electrode and one substrate on which a plurality of active devices connected to the pixel electrode are arranged in a matrix, and another substrate on which a counter electrode facing the pixel electrode is formed. It is composed of a substrate, a sealing material that joins the both substrates, and a liquid crystal sealed between the substrates and the sealing material. In this liquid crystal display element, an active element is turned on to apply a voltage to a pixel electrode, and liquid crystal molecules in a pixel formed by a liquid crystal between the pixel electrode and a counter electrode are aligned according to the applied voltage to generate an arbitrary voltage. Get the display.

[0003]

DISCLOSURE OF THE INVENTION In a display device,
It is desirable that the display image has a constant contrast and color regardless of the viewing direction. However, in the case of a liquid crystal display element, since the optical change based on the change of the alignment state of the liquid crystal molecules is detected and displayed by the polarizing plate, the orientation of the liquid crystal molecules with respect to the line of sight is relative to the viewing position. However, there is a problem that the contrast and the display color of the display image change. That is, there is a problem that the viewing angle is narrow.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a liquid crystal display element having a simple structure and a wide viewing angle. The present invention has been made in view of the above situation, and an object thereof is to provide an active matrix type liquid crystal display element having a wide viewing angle.

[0005]

In order to achieve the above object, the liquid crystal display element of the present invention comprises one substrate on which an electrode made of a conductor is formed, and a conductor opposite to the electrode of the one substrate. And a liquid crystal sealed between the one substrate and the other substrate,
An opening from which a conductor is removed is formed in at least one of the electrode formed on the one substrate and the electrode formed on the other substrate.

[0006]

With the above structure, according to the liquid crystal display element of the present invention, when a voltage is applied between the electrodes facing each other, an electric field (line of electric force) between the electrodes facing each other is generated due to the opening. They are non-parallel, and the strength of the electric field has different values depending on the location, and the alignment state of the liquid crystal molecules in each pixel is not uniform and is different at each site. That is, in each pixel,
A plurality of domains (regions) having different alignment states of liquid crystal molecules are formed. Therefore, the viewing angle of the liquid crystal display element is widened.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A wide viewing angle liquid crystal display device according to embodiments of the present invention will be described in detail below with reference to the drawings. 1 is a sectional view of the liquid crystal display device of this embodiment, FIG. 2 is a plan view of a substrate on which pixel electrodes and thin film transistors are formed, and FIG.
FIG. 4 is an enlarged perspective view of one pixel of the above configuration, and FIG. 4 is a conceptual diagram for explaining an alignment state of liquid crystal molecules.

This liquid crystal display element is of the active matrix type, and as shown in FIG.
And a pair of polarizing plates 1 arranged with the liquid crystal cell 16 interposed therebetween.
3 and 14 are formed. The liquid crystal cell 16 includes a transparent substrate 1 made of glass or the like, a transparent substrate 2 arranged to face the transparent substrate 1, a sealing material 10 for joining the transparent substrates 1 and 2 at their peripheral portions, a transparent substrate 1, 2 and a liquid crystal 11 sealed in a space formed by the sealing material 10.

As shown in FIGS. 2 and 3, a transparent pixel electrode 3 and a pixel electrode 3 are provided on the lower transparent substrate 1 in FIG.
And TFTs (thin film transistors) 4 connected to each other are arranged in a matrix. The pixel electrode 3 is made of, for example, a transparent conductive material such as ITO having a substantially square shape with one side of 100 to 400 nm, and a substantially circular opening with a diameter of 50 to 200 nm in which the transparent conductive material is removed. A part (hole) 31 is formed.

Gate lines 5 are arranged between the rows of the pixel electrodes 3 and data lines 6 are arranged between the columns of the pixel electrodes 3. The gate electrode of each TFT 4 is connected to the corresponding gate line 5, and the drain electrode is corresponding to the data line 6
And the source electrode is connected to the corresponding pixel electrode 3. The gate line 5 is connected to the row driver 21, and the data line 6 is connected to the column driver 22.

In FIG. 1, a transparent counter electrode 7 is formed on the upper transparent substrate 2 so as to face the pixel electrode 3 and to which a constant reference voltage V0 is applied. Each pixel includes a pixel electrode 3, a portion of the counter electrode 7 facing the pixel electrode 3,
And the liquid crystal 11 in between. Transparent substrates 1, 2
Alignment films 8 and 9 are respectively formed on the electrode formation surfaces of. The alignment films 8 and 9 are formed of, for example, an organic polymer compound such as polyimide, and the opposing surfaces thereof are subjected to alignment treatment such as rubbing.

The liquid crystal 11 is composed of a nematic liquid crystal or the like to which a chiral liquid crystal is added. According to the alignment treatment of the alignment films 8 and 9, the transparent substrates 1 and 2 are twisted at a predetermined angle.
It is sealed in between. The gap between the transparent substrates 1 and 2 (more accurately, the gap between the alignment films 8 and 9 = the liquid crystal layer thickness d) is held at a constant value by the gap material 12.

When a voltage is applied between the pixel electrode 3 and the counter electrode 7 of the liquid crystal display element having such a structure, the director of the liquid crystal molecule 33 changes according to the magnitude of the applied voltage, as schematically shown in FIG. The transparent substrates 1 and 2 are arranged so as to be perpendicular to the main surfaces thereof. However, because of the opening 31 formed in the pixel electrode 3, the electric field in each pixel does not become parallel as illustrated by the broken line in FIG. 4, and moreover, the liquid crystal molecule 33 becomes closer to the center of the opening 31. The applied voltage becomes small, and it becomes difficult for the liquid crystal molecules 33 to be vertically aligned.

Therefore, as shown in FIG. 4, the alignment state of the liquid crystal molecules varies depending on the position in the pixel, and the liquid crystal molecules 33 having different director directions are mixed in each pixel. That is, domains (small regions) having different alignment states are formed in each pixel. Therefore, even if the viewing direction changes, the orientation of the liquid crystal molecules 33 with respect to the line of sight does not change uniformly, and the viewing angle becomes wider.

The pixel electrode 3 having the opening 31 can be formed, for example, by forming a transparent conductive film by sputtering or the like and etching the opening 31 at the same time when the pixel electrode 3 is formed by patterning the transparent conductive film. .

The shape of the opening 31 is not limited to a circle, and may be a polygon (triangle, pentagon, hexagon ...), an ellipse, etc. as illustrated in FIG. Further, as shown in FIG. 6, a plurality of openings 31 may be formed in one pixel electrode 3.

Further, in the above embodiment, the pixel electrode 3
Although the opening portion (hole) 31 is formed in, the opening portion 71 may be formed in a portion of the counter electrode 7 facing the pixel electrode 3, as shown in FIG. 7, for example. Further, openings 31 and 71 may be formed in both the electrodes 3 and 7.

The present invention can be applied to various liquid crystal display devices. For example, a TN type liquid crystal in which the liquid crystal is twisted in the range of 90 ° to 180 ° or a liquid crystal of 180 ° to 2 ° is used.
STN type liquid crystal display element with twist alignment in the range of 70 °, twist nematic type birefringence control type color liquid crystal display element with twisted alignment of liquid crystal and displaying color by its birefringence effect, liquid crystal with homogeneous alignment The present invention can be applied to monochrome or color liquid crystal display elements having splay alignment, bend alignment, etc., and color liquid crystal display elements for performing color display by arranging red, green, and blue color filters on each pixel electrode. The type of liquid crystal used is not limited to nematic liquid crystal.

Further, in the above embodiment, an example in which the present invention is applied to a TFT liquid crystal display element using a TFT as an active element is shown, but the present invention is a liquid crystal display element using an MIM as an active element, It is also applicable to a matrix type liquid crystal display device and the like.

As described above, in the liquid crystal display element according to the embodiment of the present invention, since the opening 31 is formed in at least one of the electrodes facing each other, the electric field applied to the liquid crystal molecules in each pixel is reduced. The orientation and strength are not uniform. Therefore, the alignment state of the liquid crystal molecules is not uniform, and domains having different alignment states are formed in each pixel. Therefore, the viewing angle of the liquid crystal display element is widened. Further, since the opening 31 can be formed in the step of patterning the transparent conductive film to form the pixel electrode 3 or the counter electrode 7, an additional step for forming the opening 31 is not required, and the manufacturing thereof is easy. is there.

[0021]

As described above, according to the present invention, it is possible to obtain a liquid crystal display element having a wide viewing angle with a simple structure.

[Brief description of drawings]

FIG. 1 is a sectional view of a liquid crystal display element according to an embodiment of the present invention.

FIG. 2 is a plan view of a substrate on which pixel electrodes and thin film transistors are formed.

FIG. 3 is an enlarged perspective view for explaining the configuration of a pixel electrode.

FIG. 4 is a diagram for explaining an alignment state of liquid crystal molecules.

FIG. 5 is a diagram showing a modified example of an opening formed in a pixel electrode.

FIG. 6 is a diagram showing a modified example of an opening formed in a pixel electrode.

FIG. 7 is a diagram for explaining an example in which an opening is formed in a counter electrode.

[Explanation of symbols]

1 ... Transparent substrate, 2 ... Transparent substrate, 3 ... Pixel electrode, 4 ...
TFT (thin film transistor), 5 ... Gate line, 6 ...
..Data lines, 7 ... Counter electrode, 8 ... Alignment film, 9 ...
Alignment film, 10 ... Sealing material, 11 ... Liquid crystal, 12 ... Gap material, 13 ... Polarizing plate, 14 ... Polarizing plate, 16 ... Liquid crystal cell, 21 ... Row driver , 22 ... Column driver, 31 ...
・ Aperture, 33 ... Liquid crystal molecule, 71 ... Aperture

Claims (4)

[Claims] 1. A substrate on which one electrode made of a conductor is formed, another substrate on which an electrode made of a conductor is formed facing the electrode of the one substrate, and between the one substrate and the other substrate. A liquid crystal encapsulated in a substrate, and an opening from which a conductor is removed is formed in at least one of the electrode formed on the one substrate and the electrode formed on the other substrate. Liquid crystal display device. 2. A substrate on which a pixel electrode having an opening and a plurality of active elements connected to the pixel electrode are arranged in a matrix, and another substrate on which a counter electrode facing the pixel electrode is formed, And a liquid crystal sealed between the one and the other substrates. 3. A substrate on which a plurality of pixel electrodes and active elements connected to the pixel electrodes are arranged in a matrix, and another substrate on which a counter electrode having an opening is formed at a position facing the pixel electrode. And a liquid crystal sealed between the one and the other substrates. 4. Each pixel includes each pixel electrode, a portion of the counter electrode facing the pixel electrode, and liquid crystal disposed therebetween, and molecules of the liquid crystal are different in the pixel. 4. The liquid crystal display element according to claim 2 or 3, comprising a plurality of regions in different alignment states.