JP2000066237A - Liquid crystal display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make it possible to decrease stripes, etc., and to improve image quality by forming light shielding films, which overlap via an insulating film on data lines formed finer than regions formed with black matrices and are part of the black matrices, to a electrically floating state. SOLUTION: The insulating film 23 covering the light shielding films 21 is formed on a transparent substrate 11. The light shielding films 21 are formed on the data lines 13 in the state of overlapping on layout on the data lines 13 formed narrower than the line width of the black matrices via the insulating film 23 and in the state of shielding the light from the regions formed with the conventional data lines functioning as the black matrices. Further, the light shielding films 21 are held in a so-called electrically floating state by the insulating film 23. The coupling from the adjacent data lines may be decreased, the generation of the strips, etc., may be lessened and the image quality may be improved according to this constitution.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a liquid crystal display device, and more particularly, to light shielding of a liquid crystal display device which forms a part of a black matrix using data lines.

[0002]

2. Description of the Related Art In a conventional liquid crystal display device, as shown in a layout diagram of a main part in FIG. 3, a data line 113 formed of a metal such as aluminum is used as a part of a black matrix for shielding light. Therefore, the line width of the data line 113 is formed to be equal to the width of the formation region of the black matrix.

[0003]

However, as the miniaturization of the liquid crystal display device progresses, adjacent data lines come closer to each other and so-called resonance between the data lines cannot be ignored. That is, when sampling ends and sampling starts next to the data line in the hold state, the potential fluctuation there affects the data line in the adjacent hold state.
As a result, image quality such as streaks is deteriorated.

Normally, there are two methods for suppressing the coupling between metal wirings, all of which have the following problems. That is, in the first method of reducing the thickness of the metal film used for the data line to suppress the coupling between the data lines, the resistance of the data line increases, and the low impedance of other circuits is reduced. This will have an adverse effect on what is required.

On the other hand, by reducing the line width of the data lines and providing a sufficient distance between the data lines, coupling from an adjacent data line is reduced, and stripes and the like are reduced, thereby improving image quality. In the second method, since the data lines are originally used as a black matrix, simply making the data lines thinner causes the reverse tilt domain region of the liquid crystal layer to be located outside the black matrix region. That portion will cause light leakage.

[0006]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and is directed to a liquid crystal display device using a data line to form a part of a black matrix. Is formed thinner than the black matrix formation area, and the light-shielding film that overlaps with the data line formed smaller than the black matrix formation area via the insulating film and becomes a part of the black matrix is electrically connected. Is formed in a floating state.

In the above liquid crystal display device, since the data lines are formed narrower than the black matrix forming region, a sufficient distance between the data lines can be obtained. Rings are reduced, lines and the like are reduced, and image quality is improved. In addition, since a light-shielding film that overlaps with the data line formed smaller than the formation region of the black matrix via an insulating film and forms a part of the black matrix is formed, the data line is originally covered with the black matrix. The reverse tilt domain region of the liquid crystal layer is covered with the light-shielding film even if the data line is made thinner, so that light leakage does not occur at that portion.
Further, since the light-shielding film is formed in an electrically floating state, the light-shielding film does not load the data lines.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An example of an embodiment of the liquid crystal display device of the present invention will be described with reference to a layout diagram and a schematic sectional view of a main part of FIG. In FIG. 1, the relationship between the light shielding film and the data lines is shown by a layout diagram, and in FIG.
1 shows a schematic configuration of a cross section of the liquid crystal display device taken along line AA of FIG.

As shown in FIG. 1 and FIG.
1, a region where the light-shielding film 21 overlaps the data line 13 narrower than the line width of the black matrix, which will be described later, on the layout, and where the conventional data line functioning as the black matrix is formed. It is formed so as to shield light. A quartz substrate is used as an example of the transparent substrate 11, and a metal film is used as an example of the light shielding film 21. As the metal film, for example, a titanium film or an aluminum film is used. Further, a light-shielding film 22 is provided on the transparent substrate 11 so as to shield light between the X-axis direction portions 14 of data lines forming a black matrix in the X-axis direction (for example, horizontal direction) in the drawing. This light shielding film 22
Like the light-shielding film 21, it is formed of, for example, a titanium film or an aluminum film. Therefore, the light shielding film 2
1 and the light shielding film 22 can be formed by patterning the same metal layer. In this figure, as described above, an example in which the same metal layer is used is shown.

Further, the light shielding film 2 is formed on the transparent substrate 11.
1 and an insulating film 23 covering the light shielding film 22 are formed. The insulating film 23 allows the light shielding film 21 and the light shielding film 2 to be formed.
2 is in a so-called electrically floating state. Although not shown, a TFT (Thin FilmT) serving as a pixel transistor of the liquid crystal display device is formed on the insulating film 23.
oransistor). Further, a first insulating film 12 is formed on the insulating film 23 so as to cover the TFT (not shown). The data lines 13 are formed on the first insulating film 12. This data line 13
Is to form a black matrix in a conventional liquid crystal display device, but here, the X-axis portion 14 of the data line forming the black matrix in the X-axis direction in the drawing is used.
Except for, the line width is formed to be narrower than the formation region of the black matrix.

A second insulating film 15 is formed on the first insulating film 12 so as to cover the data lines 13 and the X-direction portions 14 of the data lines. Further, a flattening insulating film 16 is formed on the second insulating film 15, and the surface thereof is almost flattened. A pixel electrode 31 is formed at a predetermined position on the planarization insulating film 16, and a counter substrate 34 having a counter electrode 33 provided on the liquid crystal layer 32 side with a liquid crystal layer 32 interposed therebetween is provided. Thus, the liquid crystal display device 1 is configured.

The light-shielding films 21 and 22 are for light-shielding only, and may be arranged between any layers as long as they are insulated from other layers.

In the liquid crystal display device 1, the data line 13 is formed to have a smaller line width than the data line shared with the conventional black matrix.
(13A), a sufficient distance between the data lines 13 (13B) can be obtained. Thus, the data lines 13A,
Since the distance between the data lines 13B and 13B can be sufficiently set, for example, the data line 1 in a hold state after sampling is completed.
Even if the sampling is started on the data line 13B adjacent to the data line 13A, the potential fluctuation there is caused by the data line 13A in the hold state.
Will not be affected. Therefore, for example, in the data line 13A, the coupling from the adjacent data line 13B is reduced, and the streak and the like are reduced, so that the image quality is improved.

A conventional data line functioning as a black matrix is formed on the data line 13 via an insulating film 23 so as to overlap the data line 13 narrower than the line width of the black matrix on the layout. Since the light-shielding film 21 is formed so as to shield the light-blocking region, the reverse tilt domain region of the liquid crystal layer 22 originally covered with the black matrix is protected from light-shielding even if the data line 13 is thinned. Covered by the film 21. Therefore, light does not leak through the reverse tilt domain region of the liquid crystal layer 22. Therefore, the reliability of the liquid crystal display device 1 does not decrease.

Since the light shielding film 21 is formed in an electrically floating state, it does not become a load on the data line 13.

Further, since the space between the data lines 13 is expanded,
Since the margin for short-circuiting between data lines due to foreign matter generated in the manufacturing process is increased, the yield in the manufacturing process can be improved.

Further, since the data line 13 is formed thin, the capacity of the data line 13 itself is reduced. Therefore, a switch for performing sampling (for example, an analog switch) can be formed small. This switch requires a large size and occupies a considerable area on the chip. Therefore, if the area of the switch occupying a chip is reduced, the overall chip size can be reduced, so that the yield can be increased for wafers of the same size.

[0018]

As described above, according to the liquid crystal display device of the present invention, since the data lines are formed narrower than the black matrix forming region, a sufficient distance between the data lines can be secured. . As a result, the coupling from the adjacent data line can be reduced, and the occurrence of streaks and the like can be reduced, so that the image quality of the liquid crystal display device can be improved. In addition, the light-shielding film that overlaps with the data line formed thinner than the black matrix formation area via the insulating film and forms a part of the black matrix is formed in that area, so that it is originally covered with the black matrix. The reverse tilt domain region of the liquid crystal layer can be covered with the light shielding film. Therefore, light does not leak through the reverse tilt domain region of the liquid crystal layer, and thus the performance of the liquid crystal display device does not deteriorate. Further, since the light-shielding film is formed in an electrically floating state, the light-shielding film does not load the data lines. Therefore, the signal transmission speed of the data line is not reduced.

[Brief description of the drawings]

FIG. 1 is a main part layout diagram showing an example of an embodiment of a liquid crystal display device of the present invention.

FIG. 2 is a schematic sectional view showing an example of an embodiment of the liquid crystal display device of the present invention.

FIG. 3 is a main part layout diagram for explaining a relationship between a data line and a black matrix in a conventional liquid crystal display device.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Liquid crystal display device, 13 ... Data line, 21 ... Light shielding film, 2
3 ... Insulating film

Claims (1)

[Claims] 1. A liquid crystal display device in which a part of a black matrix is formed by using a data line, wherein the data line is formed to be thinner than a region where the black matrix is formed. A liquid crystal display device, wherein a light-shielding film that overlaps with the data line formed thinner via an insulating film and becomes a part of the black matrix is formed in an electrically floating state.