JPH1152428A - Liquid crystal display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily satisfy standards regarding electromagnetic radiation and to actualize the EMI-countermeasure-free liquid crystal display device by providing a shield electrode across an insulating film so that at least part of a peripheral driving circuit is covered. SOLUTION: Each pixel electrode 8 is connected to the corresponding pixel TFT 6 through a through hole of an insulating film 7. A data output circuit part and a scanning circuit part are provided as a peripheral driving circuit part 5 at the periphery of the display part of an active matrix substrate 1 and connected to respective data signal lines and scanning signal lines. The peripheral driving circuit part 5 is covered with the insulating film 7 provided over the entire surface of the substrate and a shield electrode 9 formed of the same conductive thin film with the pixel electrode 8 is provided thereupon. Further, the counter substrate 2 is provided with the counter electrode 13. Thus, the peripheral driving circuit part 5 is covered with the shield electrode 9 to eliminate malfunction due to noise entry into the peripheral driving circuit part 5 from outside and an outward leak of an electromagnetic wave generated by the operation of the peripheral driving circuit part 5.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a liquid crystal display device used as, for example, a display of a personal computer.

[0002]

2. Description of the Related Art In recent years, among flat panel displays, liquid crystal display devices having characteristics of high definition and high image quality have been actively developed. Among them, a driver monolithic liquid crystal display device in which a display portion and a drive circuit portion are formed on the same substrate by using a polycrystalline silicon thin film transistor has attracted attention.

Hereinafter, a conventional liquid crystal display device will be described with reference to FIGS.

FIG. 4 is a plan view showing a conventional driver monolithic liquid crystal display device, FIG. 5 is a sectional view taken along the line AA 'in FIG. 4, and FIG. 6 shows one pixel of the liquid crystal display device. It is an equivalent circuit diagram shown.

In this liquid crystal display device, a plurality of parallel signal lines (data signal lines) 11 and a plurality of parallel scanning lines (scan signal lines) 12 are provided on a display section 10 of an active matrix substrate 1. The data signal lines 11 and the scanning signal lines 12 are provided so as to intersect. In the vicinity of the intersection between each data signal line 11 and scanning signal line 12, a pixel thin film transistor (hereinafter, referred to as a pixel thin film transistor) for switching pixels is provided.
A TFT 6 is provided, and a pixel electrode 8 is connected to each pixel TFT 6. The data output circuit section 5a and the scanning circuit section 5 are provided around the display section 10 as the drive circuit section 5.
b and are connected to the data signal line 11 and the scanning signal line 12, respectively. When the pixel TFT 6 is driven by the scanning signal from the scanning signal line 12, the data signal line 12
Is applied to the pixel electrode 8. The liquid crystal molecules in the liquid crystal layer 4 react according to the potential difference between the voltage applied to the pixel electrode 8 and the counter electrode 13 provided on the counter substrate 2, thereby performing display.

[0006]

When such a liquid crystal display device is used as a display of a personal computer or the like, it is important to block electromagnetic waves radiated from the peripheral drive circuit. In particular, when the definition of the display unit is increased and the scale of the peripheral driving circuit is increased, the frequency of the driving clock signal is increased, so that the amount of unnecessary radiation of the electromagnetic wave is further increased. However, the amount of unnecessary radiation of electromagnetic waves is determined by standards, and the regulations are becoming stricter year by year. Therefore, it is necessary to take various countermeasures after manufacturing the liquid crystal display device in order to suppress the radiation amount, which is one of the factors for increasing the cost.

SUMMARY OF THE INVENTION The present invention has been made to solve such problems of the prior art, and has as its object to provide a liquid crystal display device capable of suppressing unnecessary radiation of electromagnetic waves without increasing the number of manufacturing steps.

[0008]

According to the liquid crystal display device of the present invention, a plurality of pixel electrodes are provided in a matrix on one of a pair of substrates opposed to each other with a liquid crystal layer interposed therebetween. In addition, in a liquid crystal display device in which a peripheral driver circuit is provided outside the display portion having the pixel electrode on the one substrate, the one substrate covers at least a part of the peripheral driver circuit, and A shield electrode made of the same conductive thin film as the pixel electrode is provided between the peripheral drive circuit and the peripheral drive circuit via an insulating film, thereby achieving the above object.

[0009] The shield electrode may be adapted to apply a predetermined potential.

[0010] The shield electrode may be made of a material that does not transmit light.

[0011] The peripheral drive circuit and the shield electrode may be provided inside a portion of the one substrate facing an end of the other substrate.

At least a part of the shield electrode may be provided in contact with a sealing material for bonding the pair of substrates.

The operation of the present invention will be described below.

In the present invention, the shield electrode is provided via the insulating film so as to cover at least a part of the peripheral drive circuit, and the electromagnetic wave does not pass through the shield electrode due to the electrostatic shielding effect. Therefore, the electromagnetic wave generated in the peripheral driving circuit portion does not propagate outside the liquid crystal display device, and the peripheral driving circuit does not malfunction due to the external electromagnetic wave. This shield electrode is made of the same conductive thin film as the pixel electrode, and the shield electrode can be formed simultaneously in the pixel electrode formation process. Therefore, the number of manufacturing steps does not increase, and there is no need to separately take measures against unnecessary radiation.

When a predetermined potential is applied to the shield electrode by, for example, grounding the shield electrode, the stability as a shield is improved.

In the case of the reflection type liquid crystal display device, since the shield electrode is made of a material which does not transmit light, it can be used as a light shielding film for the peripheral drive circuit portion.

When the peripheral drive circuit and the shield electrode are provided inside a portion facing the edge of the other substrate, the outer shape of the liquid crystal display device is reduced, and the manufacturing cost can be further reduced.

If at least a part of the shield electrode is provided so as to be in contact with a sealing material for bonding a pair of substrates, the adhesion between the sealing material made of an epoxy resin or the like and one of the substrates is increased. Peeling of the substrate is less likely to occur.

[0019]

Embodiments of the present invention will be described below with reference to the drawings. In the following drawings, parts having the same functions are denoted by the same reference numerals as those of the conventional liquid crystal display device.

Embodiment 1 FIG. 1 is a sectional view showing a liquid crystal display device of Embodiment 1.

In this liquid crystal display device, an active matrix substrate 1 and a counter substrate 2 are bonded together with a sealing material 3, and a liquid crystal is filled between the two substrates to form a liquid crystal layer 4. In the display section of the active matrix substrate 1, a plurality of parallel signal lines (data signal lines) and a plurality of parallel scan lines (scan signal lines) cross each data signal line and each scan signal line. It is provided to be. A pixel TFT 6 for switching a pixel is provided near the intersection of each data signal line and the scanning signal line, and is connected to the corresponding data signal line and scanning signal line. An insulating film 7 is provided on the entire surface of the substrate so as to cover them, and pixel electrodes 8 made of a conductive thin film are provided thereon in a matrix. Each pixel electrode 8 is connected to a corresponding pixel TFT 6 via a through hole in the insulating film 7. A data output circuit section and a scanning circuit section are provided as a peripheral drive circuit section 5 around the display section of the active matrix substrate 1, and are connected to the data signal lines and the scanning signal lines, respectively. Peripheral drive circuit section 5 includes insulating film 7 provided on the entire surface of the substrate.
, And a shield electrode 9 made of the same conductive thin film as the pixel electrode 8 is provided thereon. Counter substrate 2
Is provided with a counter electrode 13.

In this liquid crystal display device, since the peripheral drive circuit section 5 is covered with the shield electrode 9, external noise does not enter the peripheral drive circuit section 5 and malfunction does not occur. Further, the electromagnetic wave generated by the operation of the peripheral drive circuit unit 5 does not leak to the outside.

Since the shield electrode 9 can be formed simultaneously with the pixel electrode 8, the number of manufacturing steps does not increase. Further, the insulating film 7 between the peripheral drive circuit unit 5 and the shield electrode 9 may be provided separately. However, the use of the insulating film 7 provided in the display unit as in this embodiment increases the number of manufacturing steps. Nothing. Furthermore, since there is no need to separately take measures against unnecessary radiation, manufacturing costs can be reduced.

In the first embodiment, it is desirable that the shield electrode 9 be provided so as to cover the entire peripheral drive circuit section 5.

(Embodiment 2) FIG. 2 is a sectional view showing a liquid crystal display device of Embodiment 2.

This liquid crystal display device is arranged so that the edge of the active matrix substrate 1 and the edge of the counter substrate 2 are substantially aligned, and the peripheral drive circuit section 5 and the shield electrode 9 are connected to the counter substrate of the active matrix substrate 1. It is provided on the inner side than the portion facing the second end. The sealing material 3 for bonding the active matrix substrate 1 and the counter substrate 2 is provided on the insulating film 7 on the peripheral drive circuit unit 5 inside the shield electrode 9.

In this liquid crystal display device, the peripheral drive circuit section 5 and the shield electrode 9 are provided inside a portion of the active matrix substrate 1 facing the end of the counter substrate 2. Therefore, the outer shape of the liquid crystal display device can be reduced, and the number of liquid crystal display devices that can be manufactured using one glass substrate can be increased. Therefore, the manufacturing cost of the liquid crystal display device can be further reduced.

In addition, the substrate configuration of the liquid crystal display device is generally such as shown in FIG. 1 or FIG. Or the form shown in FIG. 3 described later.

(Embodiment 3) FIG. 3 is a sectional view showing a liquid crystal display device of Embodiment 3.

This liquid crystal display device is arranged so that the edge of the active matrix substrate 1 and the edge of the counter substrate 2 are almost aligned, and the peripheral drive circuit section 5 and the shield electrode 9 are connected to the counter substrate of the active matrix substrate 1. It is provided on the inner side than the portion facing the second end. The sealing material 3 for bonding the active matrix substrate 1 and the counter substrate 2 is provided on the shield electrode 9. The sealing material 3 is made of an epoxy resin or the like, and the adhesion between the sealing material 3 and the shield electrode 9 made of a conductive thin film is determined by the sealing material 3
Is better than the adhesion with the insulating film 7 made of acrylic resin, polyimide or the like.

In this liquid crystal display device, the sealing material 3
Is provided on the shield electrode 9, so that the sealing material 3
And the active matrix substrate 1 can be improved in adhesion. Therefore, defects such as peeling of the opposing substrate 2 can be reduced, and the yield of the liquid crystal display device can be improved.

In the third embodiment, it is desirable that the shield electrode 9 is provided in the entire region where the sealing material 3 is formed.

In the first to third embodiments, it is desirable to apply a constant potential to the shield electrode 9. The reason for this is that if the shield electrode 9 is kept electrically floating, electric charges may be accumulated between the peripheral drive circuit section 5 and the shield electrode 9, which may cause a malfunction. For example, the potential of the shield electrode 9 may be made constant by grounding the shield electrode 9, the potential of the counter electrode may be given to the shield electrode 9, or another circuit for giving a fixed potential to the shield electrode 9. May be separately provided.

In the first to third embodiments, when the liquid crystal display device is of a transmission type, a transparent conductive film such as ITO can be used as a material of the pixel electrode 8 and the shield electrode 9. When the liquid crystal display device is of a reflection type, a material that does not transmit light, such as a metal such as aluminum, is used as the material of the pixel electrode 8, so that the shield electrode 9 does not transmit light. Therefore, the shield electrode 9 can also be provided with a function as a light shielding film for the peripheral drive circuit unit 5.

[0035]

As described in detail above, according to the present invention,
Since the shield electrode is provided via an insulating film so as to cover at least a part of the peripheral driving circuit, the electromagnetic wave generated in the peripheral driving circuit does not leak out of the liquid crystal display device, and the electromagnetic wave from the outside does not leak. Does not cause the peripheral drive circuit to malfunction. Therefore, the standard regarding electromagnetic radiation can be easily satisfied, and a liquid crystal display device free of EMI measures can be realized.

Further, according to the present invention, since the shield electrode is made of the same conductive thin film as the pixel electrode, the number of manufacturing steps does not increase, and there is no need to take measures against unnecessary radiation. Thus, unnecessary radiation of electromagnetic waves can be suppressed, and the manufacturing cost of the liquid crystal display device can be reduced.

In the present invention, by applying a predetermined potential to the shield electrode, the stability as a shield can be improved. Therefore, the malfunction of the peripheral drive circuit can be prevented, and the reliability can be further improved.

Further, by applying the present invention to a reflection type liquid crystal display device, a shield electrode can be used as a light shielding film for a peripheral drive circuit portion. Therefore, the reliability of the liquid crystal display device can be further improved.

In the present invention, the outer shape of the liquid crystal display device can be reduced by providing the peripheral drive circuit and the shield electrode inside a portion of one substrate which is opposed to an end of the other substrate. . Therefore, the manufacturing cost of the liquid crystal display device can be further reduced.

Further, in the present invention, by providing at least a part of the shield electrode so as to be in contact with the sealing material for bonding the pair of substrates, the adhesion between the sealing material and one of the substrates can be improved. it can. Therefore, defects such as peeling of the other substrate can be reduced, and the yield of the liquid crystal display device can be increased.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a liquid crystal display device according to a first embodiment.

FIG. 2 is a cross-sectional view illustrating a liquid crystal display device according to a second embodiment.

FIG. 3 is a cross-sectional view of an active matrix substrate included in a liquid crystal display device according to a third embodiment.

FIG. 4 is a plan view showing a conventional driver monolithic liquid crystal display device.

FIG. 5 is a cross-sectional view taken along line A-A ′ of FIG. 4;

FIG. 6 is an equivalent circuit diagram illustrating one pixel of the liquid crystal display device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Active matrix substrate 2 Counter substrate 3 Sealing material 4 Liquid crystal layer 5 Peripheral drive circuit unit 5a Data output circuit unit 5b Scanning circuit unit 6 TFT 7 Insulating film 8 Pixel electrode 9 Shield electrode 10 Display unit 11 Data signal line 12 Scanning signal line 13 Counter electrode

Claims (5)

[Claims] 1. A plurality of pixel electrodes are provided in a matrix on one of a pair of substrates opposed to each other with a liquid crystal layer interposed therebetween, and the pixel electrodes on the one substrate are arranged in a matrix. In a liquid crystal display device provided with a peripheral driving circuit outside a display unit having the same, the one substrate covers at least a part of the peripheral driving circuit, and an insulating film is provided between the peripheral substrate and the peripheral driving circuit. A liquid crystal display device provided with a shield electrode made of the same conductive thin film as the pixel electrode. 2. The liquid crystal display device according to claim 1, wherein the shield electrode is adapted to apply a predetermined potential. 3. The liquid crystal display device according to claim 1, wherein the shield electrode is made of a material that does not transmit light. 4. The device according to claim 1, wherein the peripheral drive circuit and the shield electrode are provided inside a portion of the one substrate facing an end of the other substrate. Liquid crystal display device. 5. At least a part of the shield electrode,
The liquid crystal display device according to claim 1, wherein the liquid crystal display device is provided in contact with a sealant for bonding the pair of substrates.