JPH07119918B2 - Liquid crystal display - Google Patents

Description

The present invention relates to a liquid crystal display device, and more particularly to the structure of a storage capacitor.

(B) Conventional Technology In general, liquid crystal display devices are being developed at a rapid pace because low power consumption and large capacity can be achieved.

However, when the screen size is increased and the pixel size is reduced, a large number of defects and mask shifts are generated, and the actual yield rate is extremely low. In addition, the liquid crystal generally has a drawback that it is very difficult to see as compared with an image on a cathode ray tube. Therefore, each company proposes various structures to solve this problem. An example of this is FIG. 2, which will be explained.

First, there is an insulating transparent substrate, such as a glass substrate (50),
A gate line (51) is provided on this substrate. An auxiliary capacitance electrode (52), which is formed at the same time as the gate line (51) and is a problem of the present application, is provided as shown by a broken line. An insulating film made of a silicon nitride film or the like is covered therewith to form an active layer (53) made of a semiconductor layer. Here, the active layer (53) is made of, for example, amorphous silicon or polysilicon. Further, after the insulating layer is covered, a drain electrode (54) shown by a solid line is formed on one side of the active layer (53), and a source electrode (55) shown by a solid line is formed on the other side. A display electrode (56) made of ITO is formed in contact with the source electrode. Here, the drain electrode is integrally formed with the image line of the figure number (57). Further, an alignment film covering the display electrode (56), the drain electrode (54) and the transistor is formed.

On the other hand, a common electrode and an alignment film are formed in the lower layer of another glass substrate facing the glass substrate (50), and these two glass substrates are provided so as to face each other, and a liquid crystal is sealed between them. ing.

(C) Problem to be Solved by the Invention Here, the light shielding film is generally formed on the counter electrode substrate. However, when the liquid crystal display device is viewed from an oblique direction, parallax may occur and the transmitted light may be visually observed, and the original effect of the light-shielding film, the so-called black matrix effect (avoidance of color mixture by separating color pixels) may be lost. is there.

In order to solve this problem, there is a configuration in which a light shielding film is formed on the TFT substrate, which is the reverse of the configuration described above.

In either case, the light shielding film is generally provided between the display electrodes (56).

Now, considering the light-blocking area in FIG. 2, the light-shielding film provided between the auxiliary capacitance electrode (52) and the display electrode (56) shown by the broken line corresponds to the auxiliary capacitance which actually becomes the display area. Around the area where the electrode (52) and display electrode (56) do not overlap,
This blocking area is formed very wide, and there is a problem that the generally-known presence of the black matrix becomes very remarkable.

Moreover, when this display device is applied to a liquid crystal projector, there is a problem that the presence of the black matrix becomes more remarkable because it is enlarged.

(D) Means for Solving the Problems The present invention has been made in view of the above problems, and the auxiliary having a width substantially equal to the distance from the display electrode (13) to another adjacent display electrode (13). This is solved by providing the auxiliary capacitance electrode (14) so that the display electrode regions D that do not overlap with the capacitance electrode (14) are substantially evenly spaced.

(E) Action The lines of the light-shielding film formed between the display electrodes (13) and the lines of the auxiliary capacitance electrodes (14) are evenly arranged on the grid as shown in FIG. A region where the auxiliary capacitance electrode (14) and the display electrode (13) do not overlap each other, that is, the periphery of a so-called display region D is formed of a light shielding layer having a uniform width,
Further, since the display region D is formed by being divided into a plurality of parts, the presence of the black matrix is apparently reduced.

(F) Example The present invention will be described with reference to FIG.

First, there is an insulating transparent substrate (10), for example, a glass substrate.
On this glass substrate (10), a gate electrode (11) (formed integrally with the gate line (1)) formed by Cr sputtering is provided on the left and right between the display electrodes (13) to be formed. It is extended and provided. An auxiliary capacitance electrode (14) is formed at the same time as the gate electrode (11) as shown by a broken line.

Further, the entire surface of the substrate including the gate electrode (11) and the auxiliary capacitance electrode (14) is covered with a gate insulating film made of a silicon nitride film.

A semiconductor active layer (15) made of N-type amorphous silicon is formed on the gate insulating film corresponding to the gate electrode.
Is provided.

Further, on the gate insulating film, a display electrode made of ITO (13)
Are formed.

Contact layers made of N ⁺ type amorphous silicon are formed on both ends of the semiconductor active layer (15).
Here, for convenience of drawing, the contact layer is not shown. Further, between the contact layers formed on both ends, a silicon nitride film of an insulating layer is formed in order to prevent the semiconductor active layer from being etched when the contact layers are etched.

Further, a source electrode (16) is formed between the contact layer corresponding to the source region and the display electrode, and a drain electrode (18) is formed integrally with the drain line (17) on the contact layer corresponding to the drain region. ) Has been formed. Further, the cell has a triangle structure in which two display electrodes (13), (13) adjacent to each other and the lower display electrode (13) have a triangle structure for color correspondence. The upper display electrodes also have a triangle structure. Therefore, in reality, the drain line extends in a zigzag pattern in the vertical direction.

Further, an alignment film covering the display electrode, the source electrode, the drain electrode, the drain line, and the transistor is formed, and a common electrode and an alignment film are formed under the other glass substrate, and the one substrate and the other substrate are formed. The substrates are provided so as to face each other, and a liquid crystal is sealed between them.

Here, as described in the section of the problem to be solved by the invention, the light shielding film is formed on the glass substrate (10) on which the transistor is formed or on the glass substrate on which the counter electrode is formed. The formation region is mainly provided in a region corresponding to the display electrode (13), and the overlapping region of the light shielding film and the display electrode (13) is made as small as possible so that the display portion D is as large as possible.

The feature of the present invention lies in the shape of the auxiliary capacitance electrode (14). As shown in FIG. 1, the auxiliary capacitance electrode (14) apparently divides the display electrode (13) into a plurality of parts, and in this case, it is divided into four parts, and the width is adjacent to the display electrode (13). The distance from the electrode (13) is substantially the same.

As described above, the light-shielding film formation region is provided between the display electrodes (13), and the overlapping region of the light-shielding film and the display electrode (13) is made as small as possible so that the display portion D is as large as possible. Therefore, the line formed between the display electrodes (13) is substantially the same as the region formed by the light shielding film, and this region is one of the black stripes. Further, since the auxiliary capacitance electrode (14) is made of the same material as the gate electrode (11), it is impermeable, and this is the other of the black matrix. Therefore, the two black matrices form an apparently integrated and uniformly formed lattice.

Here, the non-overlapping region D of the auxiliary capacitance electrode (14) and the display electrode (13) is formed to be very small for the convenience of the drawing, but in reality, the width A of the auxiliary capacitance electrode (14) is set to 1 Assuming that, one side B of the non-overlapping area is about 10 to 20.
For example, for an apparent black matrix having a width of 5 to 30 μm, one side of the display area D is 50 μm to 200 μm. Therefore, the apparent black matrix width is narrower than that of the conventional structure, and since one pixel is divided into a plurality of parts, the presence of the black matrix is apparently reduced.

Here, the display area D is shown as a square, but it may be a rectangle or the like, and the number of divisions is not limited to four divisions, but six divisions and eight divisions.
It may be split ... However, the apparent display area D is
All must be of substantially the same size and evenly distributed.

(G) Effect of the Invention As is apparent from the above description, the apparent black matrix width is made small, the width between the display electrodes and the width of the auxiliary capacitance electrode are substantially the same, and the display area is evenly divided. The presence of the black matrix can be reduced by dispersing it in the.

Therefore, even if the display device having this structure is applied to a projector, it is possible to provide a clear image to the user because the presence of the display device can be far removed.

[Brief description of drawings]

FIG. 1 is a plan view of a liquid crystal display device of the present invention, and FIG.
It is a top view of the conventional liquid crystal display device.

Claims (3)

[Claims] 1. A plurality of gate lines and a plurality of image lines cross-arranged in a matrix shape, a transistor controlled by the gate line at the intersection, and a transistor connected to the transistor, and the transistor via the transistor. A liquid crystal cell having at least a display electrode to which an image signal is supplied from an image line, an auxiliary capacitance electrode made of an opaque material that supplements the liquid crystal cell, and a display adjacent to the display electrode. In a liquid crystal display device having at least a light-shielding film provided to shield light between electrodes, the auxiliary capacitance electrode has a width substantially equal to a distance from the display electrode to another display electrode adjacent to the auxiliary capacitance electrode. A liquid crystal display device characterized in that non-overlapping regions of the display electrodes with the auxiliary capacitance electrodes are arranged at substantially equal intervals on their four sides. Place 2. A plurality of gate lines and a plurality of image lines cross-arranged in a matrix form, a transistor controlled by the gate line at the intersection, and a transistor connected to the transistor, and the transistor via the transistor. A liquid crystal cell having at least a display electrode to which an image signal is supplied from an image line, an auxiliary capacitance electrode made of an opaque material that supplements the liquid crystal cell, and a display adjacent to the display electrode. In a liquid crystal display device having at least a light-shielding film provided to shield light between electrodes, the auxiliary capacitance electrode is formed to have a width substantially equal to that of the light-shielding film and is overlapped with the display electrode in vertical and horizontal directions. By this, the light-shielding region formed by the auxiliary capacitance electrode and the light-shielding film is formed in a grid shape having substantially the same width, and the grid-shaped eye A liquid crystal display device, wherein a non-overlapping region of the display electrode with the auxiliary capacitance is present in a portion. 3. The liquid crystal display device according to claim 1, wherein the light shielding film is formed on at least one of a pair of glass substrates forming the liquid crystal display device.