JP3337045B2 - Liquid crystal display - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a substrate having a common electrode film on one surface and a peripheral wiring film on the periphery of one surface and a substrate having a display pixel electrode film inside the substrate. The present invention relates to a liquid crystal display device in which a liquid crystal is sealed in a space formed between substrates in a direction facing each other and adhered to a peripheral portion at a predetermined interval therebetween.

[0002]

2. Description of the Related Art FIG. 4 shows a known liquid crystal display device. In the drawing, reference numeral 1 denotes a TFT substrate on which a thin film transistor is formed, and further, display pixel electrode films 2, 2,..., And a peripheral wiring film 3 located outside thereof are formed on the surface thereof. Is formed. This peripheral wiring film 3 forms a power supply voltage line of, for example, 14V.
Reference numeral 4 denotes a common connection film serving as a relay point for applying a predetermined potential to a common electrode film (7) described later, and reference numeral 5 denotes a TFT-side alignment film that covers the display pixel electrode films 2, 2,. 6
Is a CF substrate, on the surface of which a color filter is formed, and on the surface of the color filter, a common electrode film 7 is formed on substantially the entire surface except for the peripheral portion. Reference numeral 8 denotes a CF-side alignment film formed on the surface of the common electrode film 7.

In the TFT substrate 1 and the CF substrate 6, the surfaces on which the thin film transistors, the display pixel electrode films 2, 2,..., Etc. and the common electrode film 7 are formed are opposed to each other. For example, a thermosetting resin is adhered to the peripheral portion so as to form a gap of about 3.8 μm), and a liquid crystal 9 is sealed in a space formed therebetween. In this liquid crystal display device, a DC potential of, for example, 5.6 V is applied to the common electrode film 7 on the surface of the CF substrate 6 during use. Then, a potential of 5.6 V is applied to each display pixel electrode film 2 in the case of non-lighting. In the case of lighting, a potential higher than 5.6 V, for example, 4.5 V (that is, 1 V).
0.1V) and a pulsating potential that changes at a constant cycle between a potential 4.5V lower than 5.6V (i.e., 1.1V).

[0004]

By the way, in the conventional liquid crystal display device as shown in FIG. 4, there is provided between the peripheral wiring film 3 forming a 14V power supply line and the common electrode film 7.
As a result, a potential difference of 8.4 V is generated, and as a result, a DC voltage of 8.4 V is applied to the portion of the liquid crystal layer 9 on the peripheral wiring film 3, and as shown in FIG. An electric double layer is formed between the alignment film 8 and the liquid crystal layer 9 to deteriorate the image quality. As shown in FIG. 5B, the electric double layer gradually becomes deeper with the passage of time (for example, several hours). There was a problem that spread. Such an electric double layer is substantially saturated when it extends about 1 mm, and does not extend any further. For example, in the case of a liquid crystal display device used for a small screen such as a view finder of a video camera, the width of 1 mm depends on Image quality degradation is not allowed. Such an electric double layer, when the temperature of the liquid crystal display device increases, for example,
When the temperature is 50 to 70 ° C. or higher, the temperature is more likely to occur.

[0005] The present invention has been made to solve the above problem, display the peripheral wiring film on the inside perimeter of the substrate and one surface with a common electrode film on one surface
In a liquid crystal display device in which a substrate having an indicator pixel electrode film is adhered to a peripheral portion thereof at a predetermined interval in a direction in which the respective surfaces face each other and a liquid crystal is sealed in a space generated between the substrates, On the substrate side on which the film is formed, an object is to prevent an electric double layer from being formed on a portion of the liquid crystal display pixel electrode film due to a potential difference between the peripheral wiring film and the common electrode film, thereby preventing image quality deterioration. I do.

[0006]

Means for Solving the Problems] The liquid crystal display device according to claim 1, provided with the peripheral wiring film, an electrically floating dummy pixel electrode film not receive a signal voltage between the display pixel electrode film and wherein the Do that.

According to a second aspect of the present invention, there is provided the liquid crystal display device according to the first aspect, wherein a plurality of the dummy pixel electrode films are viewed in a cross section extending from the center to the outside of the substrate on which the dummy pixel electrode film is formed. And

[0008]

SUMMARY OF] According to the liquid crystal display device according to claim 1, since the electrically floating the dummy pixel electrode film is provided between the display pixel electrode film and the peripheral wiring film, the dummy pixel electrode film This prevents the formation of an electric double layer in the liquid crystal, thereby preventing the image quality from deteriorating.

[0009] According to the liquid crystal display device according to claim 2, the number of electrically floating the dummy pixel electrode film present between the table <br/>示画pixel electrode film and the peripheral wiring film is more Thus, generation of an electric double layer can be more effectively prevented, and image quality deterioration due to the electric double layer can be prevented.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the illustrated embodiments. FIG. 1 is a sectional view showing one embodiment of the liquid crystal display device of the present invention. This liquid crystal display device is different from the conventional liquid crystal display device shown in FIG. 4 in that the peripheral wiring film 3 is covered with a shield wiring film (11) via an insulating film (10), and the shield wiring film (11) is Although they are greatly different in that they are electrically connected to the common electrode film 7, they are common in other points, and the common points have already been described. Therefore, the description is omitted, and only the differences are described. I decided to.
In addition, common portions are denoted by common reference numerals throughout the drawings.

Reference numeral 10 denotes an insulating film that covers the peripheral wiring film 3 forming a power supply line. Reference numeral 11 denotes a shield wiring film that covers the peripheral wiring film 3 via the insulating film 10 and electrically connects with the common electrode film 7 of the CF substrate 6. It is connected. According to such a liquid crystal display device, the lower portion of the liquid crystal 9 on the peripheral wiring film 3 is in contact with the shield 3 and has substantially the same potential as the upper common electrode film 3, so that there is no potential difference between the upper and lower portions. Therefore, there is no possibility that an electric double layer is formed, and there is no possibility that image quality is deteriorated in a peripheral portion of the screen.

FIG. 2 is a sectional view showing a second embodiment of the liquid crystal display device of the present invention. The present liquid crystal display device will also be described only for the points different from the conventional liquid crystal display device. The present liquid crystal display device is formed such that the common electrode film 8 on the surface of the CF substrate 6 (the surface on the liquid crystal side) hardly protrudes from a position corresponding to the formation region of the display pixel electrode films 2, 2,. I have. Specifically, between the peripheral edge of the peripheral wiring film 7 and the outer surface of the display pixel electrode film 2 corresponding to the peripheral edge, the peripheral edge of the peripheral wiring film 7 is located slightly outside, and the deviation d is 100
μm or less.

In the present liquid crystal display device, the common electrode film 8 is formed so as to hardly protrude from a position corresponding to the formation region of the display pixel electrode films 2, 2,.
The common electrode film 7 does not exist at a position corresponding to the peripheral wiring film 3 of FIG. Therefore, the potential difference between the common electrode film 8 and the peripheral wiring film 3 is not applied to the portion of the liquid crystal 9 on the peripheral wiring film 3. Therefore, there is no possibility that an electric double layer is formed, and thus there is no possibility that image quality is deteriorated in the peripheral portion of the screen.

FIG. 3 is a sectional view showing a third embodiment of the liquid crystal display device of the present invention. The present liquid crystal display device will also be described only for the points different from the conventional liquid crystal display device. In the present liquid crystal display device, of the display pixel electrode films 2, 2,..., The outer display pixel electrode film 2 closest to the peripheral wiring film 3 is a dummy pixel electrode film 2a and is not used for display. That is, the display voltage is not applied to the dummy pixel electrode film 2a. Specifically, it is made electrically floating. Therefore, the effective pixel exists inside it.

Since there is a dummy pixel electrode film 2a between the effective pixel and the peripheral wiring film 3, the display pixel electrode closest to the peripheral wiring film 3 among the display pixel electrode films 2, 2,. The film 2 also has a distance of about 100 μm between the film 2 and the peripheral wiring film 3. As a result, the DC applied portion of the liquid crystal 9 is far from the effective pixels, and the electric double layer hardly affects the effective pixel region. Therefore, according to the present liquid crystal display device, there is little possibility that the image quality is deteriorated in the peripheral portion of the screen.

It is noted that not only the display pixel electrode film 2 closest to the peripheral wiring film 3 but also the display pixel electrode film 2 on the inner side thereof is electrically floating as shown by a two-dot chain line in FIG. The dummy pixel electrode film 2a may be used. Then
Since the display pixel electrode film 2 closest to the peripheral wiring film 3 among the display pixel electrode films 2, 2,... The effect on the effective pixel area due to the multilayer is less likely to occur, and the effect of preventing image quality deterioration can be enhanced.

[0017]

According to the liquid crystal display device according to claim 1, according to the present invention, since an electrically floating dummy pixel electrode film between the <br/> display pixel electrode film and the peripheral wiring film is provided,
The formation of an electric double layer in the liquid crystal is prevented by the dummy pixel electrode film, and the image quality does not deteriorate due to the electric double layer.

According to the liquid crystal display device according to claim 2, the number of electrically floating the dummy pixel electrode film present between the table <br/>示画pixel electrode film and the peripheral wiring film is more Thus, generation of an electric double layer can be more effectively prevented, and image quality deterioration due to the electric double layer can be prevented.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a first embodiment of the liquid crystal display device of the present invention.

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

FIG. 3 is a sectional view showing a third embodiment of the liquid crystal display device of the present invention.

FIG. 4 is a sectional view showing a conventional example of a liquid crystal display device.

FIGS. 5A and 5B are cross-sectional views showing problems of a conventional liquid crystal display device.

[Explanation of symbols]

 Reference Signs List 1 TFT substrate 2 display pixel electrode film 2a dummy pixel electrode film 3 peripheral wiring film 6 CF substrate 7 common electrode film 9 liquid crystal 10 insulating film 11 shield wiring film

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) G02F 1/1345 G02F 1/1368

Claims (2)

(57) [Claims] 1. A substrate having a common electrode film on one surface and a peripheral wiring film on a peripheral portion of the one surface inside a display image.
A substrate having an element electrode film is adhered at a peripheral portion with a predetermined interval between the surfaces in a direction facing each other,
In the liquid crystal display device in which liquid crystal is sealed space formed between the substrate and the peripheral wiring film, an electrically be provided floating dummy pixel electrode film not receive a signal voltage between the display pixel Characteristic liquid crystal display 2. The liquid crystal display device according to claim 1, wherein there are a plurality of said dummy pixel electrode films as viewed in a cross section extending from the center to the outside of the substrate on which said dummy pixel electrode films are formed.