JPH10161102A - Liquid crystal display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the leakage of light due to disclination and to enlarge a numerical aperture. SOLUTION: A light shield part 6d of a right angled isosceles triangular shape is provided integrally on the inside of a bent part of a nearly L-shaped part consisting of a line part 6a and a left draw-out part 6b of a cumulative capacitance line 6. Then, the matter that a disclination occurrence area shown by diagonal lines is light shielded sufficiently by this light shield part 6d, the line part 6a in the vicinity of it and the left draw-out part 6b is made possible. Then, the necessity that the leakage of light due to the disclination is prevented by a black mask is eliminated. Thus, the left side of the opening part 15 of the black mask is arranged between the left side of a pixel electrode 5 and the right edge of the left draw-out part 6b, and the numerical aperture is enlarged.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a liquid crystal display device.

[0002]

2. Description of the Related Art An active matrix type liquid crystal display device includes a scanning line, a signal line and a storage capacitor line, and is connected to a pixel electrode near each intersection of the scanning line and the signal line and to the pixel electrode. Some include a thin film transistor as a switching element.

FIGS. 2 and 3 show a part of an active matrix panel of such a conventional liquid crystal display device. This active matrix panel has a glass substrate 1. A scanning line (gate line) 2 and a signal line (drain line) 3 are provided in a matrix on the upper surface side of the glass substrate 1, and a thin film transistor 4 and a pixel electrode 5 are provided near each intersection thereof. The storage capacitor line 6 is provided in parallel with.

That is, the scanning line 2 including the gate electrode 7 is formed at a predetermined position on the upper surface of the glass substrate 1, the storage capacitor line 6 is formed at another predetermined position, and the gate insulating film is formed over the entire upper surface. A film 8 is formed. In this case, the gate electrode 7 is formed at a predetermined location on the upper surface of the gate insulating film 8.
A semiconductor layer 9 made of amorphous silicon is formed at a portion corresponding to the above, and a blocking layer 10 is formed at the center of the upper surface of the semiconductor layer 9. Ohmic contact layers 11 and 12 made of n ⁺ silicon are formed on both sides of the upper surfaces of the semiconductor layer 9 and the blocking layer 10. The drain electrode 13 is formed on the upper surface of the ohmic contact layer 11 and the ohmic contact layer 1 is formed.
The source electrode 14 is formed on the upper surface of the substrate 2. Also,
Simultaneously with the formation of these electrodes 13 and 14, the drain electrode 13
Is formed. A pixel electrode 5 made of ITO is formed at a predetermined position on the upper surface of the gate insulating film 8 so as to be connected to the source electrode 14.

The storage capacitor line 6 includes a line portion 6 a provided in parallel with the scanning line 2 at a position corresponding to the upper side of the pixel electrode 5, and a line portion 6 a extending from the line portion 6 a to the pixel electrode 5.
Drawer 6b pulled out along the left side and right side of
6c. A line portion 6a and a drawing portion 6b,
Each predetermined portion of 6c is overlapped with each predetermined side of the pixel electrode 5, and the overlapped portion forms a storage capacitor portion. On the other hand, although not shown, a pixel capacitance portion is formed by the pixel electrode 5, a common electrode opposed to the pixel electrode 5, and a liquid crystal disposed therebetween. In addition,
In FIG. 1, what is indicated by an alternate long and short dash line is an opening 1 of a black mask formed on a common electrode panel having a common electrode.
5 is shown. Details of the opening 15 of the black mask will be described later.

[0006] When the liquid crystal display device is of a twisted nematic type, disclination (discretion) is required.
Deterioration of display quality due to the occurrence of crination is a major problem. That is, under certain conditions, as shown by hatching in FIG. 2, disclination occurs in a substantially L-shaped region at the intersection of the upper side and the left side of the pixel electrode 5. The area where the disclination has occurred serves as an abnormal display section in which light leakage occurs and white spots occur. As described above, when a white spot occurs in a part of one pixel, the contrast of the entire display unit of the liquid crystal display device is significantly reduced, and the display quality is significantly reduced.

As a method of improving this, conventionally, a light leakage due to the disclination is prevented by providing a black mask in accordance with the position where the disclination occurs. Therefore, next, the opening 15 of the black mask indicated by a dashed line in FIG. 2 will be described. The upper side of the opening 15 corresponds to the upper side of the pixel electrode 5 and the line section 6.
a, the left side is disposed inside the right edge of the left extraction portion 6b, the right side is disposed in the middle between the right side of the pixel electrode 5 and the left edge of the right extraction portion 6c, and the lower side is It is arranged inside the lower side of the pixel electrode 5. Among these, the reason why the right side of the opening 15 is arranged between the right side of the pixel electrode 5 and the left edge of the right lead-out portion 6c is when the active matrix panel and the common electrode panel are bonded together via a sealing material. In some cases, a positional deviation of about several μm may occur.
Is to be prevented from protruding from between the right side of the pixel electrode 5 and the left edge of the right lead-out portion 6c.

[0008]

By the way, when both panels are pasted together, if the position shifts in the left-right direction, it is assumed that
It is assumed that the right side of the opening 15 coincides with the right side of the pixel electrode 5. Then, according to the displacement amount in this case, the opening 1
The left side of 5 moves leftward in FIG.
However, even in such a case, the left side of the opening 15 is a left portion of the disclination occurrence area indicated by hatching (that is,
It is necessary to prevent the L-shaped generation region from being too close to the portion substantially parallel to the left side of the opening 15).
For this reason, the left side of the opening portion 15 is disposed at a position which is largely separated from the left side of the disclination generation area shown by oblique lines to some extent in anticipation of the above-described positional shift. As a result, there is a problem that the aperture ratio is reduced. An object of the present invention is to prevent light leakage due to disclination and to increase the aperture ratio.

[0009]

According to the present invention, the entire area of a disclination generation area is shielded from light by a storage capacitor line.

According to the present invention, since the entire area where the disclination occurs is shielded from light by the storage capacitor line, it is not necessary to prevent light leakage due to the disclination using the black mask. As a result, for example, FIG.
In this case, even if the left side of the opening 15 is moved to the left, light leakage due to disclination does not occur, so that the aperture ratio can be increased.

[0011]

FIG. 1 shows a main part of an active matrix panel of a liquid crystal display according to an embodiment of the present invention. In this figure, the same reference numerals are given to the same names as those in FIG. 2, and the description thereof will be omitted as appropriate. This active matrix panel also includes a scanning line 2, a signal line 3, and a storage capacitor line 6, and a pixel electrode 5 and a thin film transistor 4 connected to the pixel electrode 5 near each intersection of the scanning line 2 and the signal line 3. Is the same as the conventional case shown in FIG. One point of this active matrix panel different from the conventional case shown in FIG. 2 is that a light shielding portion 6d is provided inside a bent portion of a substantially L-shaped portion composed of a line portion 6a and a left extraction portion 6b of the storage capacitor line 6. Are provided integrally. The light-shielding portion 6d has a right-angled isosceles triangle shape having two sides at the inner end of the bent portion of the substantially L-shaped portion. Another point is that the left side of the opening 15 is located between the left side of the pixel electrode 5 and the right edge of the left lead-out portion 6b.

As described above, in this liquid crystal display device, a right-angled isosceles triangular light-shielding portion 6d is provided inside a substantially L-shaped bent portion including the line portion 6a and the left extraction portion 6b of the storage capacitor line 6. Is provided, the light-shielding portion 6d and the line portion 6a and the left lead-out portion 6b near the light-shielding portion 6d can sufficiently shield the disclination occurrence area indicated by oblique lines. Therefore, it is not necessary to prevent light leakage due to disclination with a black mask. As a result, as described above, the left side of the opening 15 can be arranged between the left side of the pixel electrode 5 and the right edge of the left extraction portion 6b, and the aperture ratio can be increased.

In the above embodiment, the light-shielding portion 6d has a right-angled isosceles triangle shape. However, the light-shielding portion 6d may have a simple right-angled triangle shape, and may have a quadrangular shape in some cases. Also, the position where the light shielding portion 6d is provided is, of course, the disclination occurrence region, so that if the disclination occurrence region is located at another position, it may be provided accordingly.

[0014]

As described above, according to the present invention, since the entire area where the disclination occurs is shielded from light by the storage capacitor line, it is not necessary to prevent light leakage due to the disclination using the black mask. As a result, the aperture ratio can be increased.

[Brief description of the drawings]

FIG. 1 is a plan view of a main part of an active matrix panel of a liquid crystal display device according to an embodiment of the present invention.

FIG. 2 is a plan view of a part of an active matrix panel of a conventional liquid crystal display device.

FIG. 3 is a sectional view taken along line AA of FIG. 2;

[Explanation of symbols]

 2 scanning line 3 signal line 4 thin film transistor 5 pixel electrode 6 storage capacitor line 6d light shielding part

Claims (3)

[Claims] 1. A liquid crystal display comprising a scanning line, a signal line, and a storage capacitor line, and a pixel electrode near each intersection of the scanning line and the signal line, and a switching element connected to the pixel electrode. 2. A liquid crystal display device according to claim 1, wherein the storage capacity line shields the entire area of the disclination occurrence area from light. 2. The storage capacitor line according to claim 1, wherein said storage capacitor line has a substantially L-shaped portion overlapping with predetermined two adjacent sides of said pixel electrode.
A liquid crystal display device comprising a light-shielding portion inside a bent portion of the character portion. 3. The liquid crystal display device according to claim 2, wherein the light-shielding portion has a right-angled triangular shape having two sides on an inner end of the bent portion of the substantially L-shaped portion.