JPH089709Y2 - Color liquid crystal display - Google Patents

Description

The present invention relates to a color liquid crystal display device used in a liquid crystal television or the like, and more particularly to an electrostatic shield for the display device,
And the electromagnetic shield.

(Prior Art) In recent years, in order to reduce the thickness, weight and power consumption of displays of televisions and personal computers, color liquid crystal display devices have been actively developed and commercialized in place of conventional CRTs. There is. Such color liquid crystal display devices are based on liquid crystal technology and thin film forming technology.

FIG. 3 shows the structure of the color liquid crystal display device. The color liquid crystal display device mainly includes a liquid crystal panel 51, an IC substrate 52, a metal shield cover 53, and a metal shield case 54. A drive circuit IC55 is arranged on the IC substrate 52. The metal shield lid 53 and the metal shield case 54 are provided to shield the periphery of the liquid crystal panel 51 and the drive circuit IC55 on the IC substrate 52. The liquid crystal panel 51 is driven by the drive circuit IC to display an image.

FIG. 4 shows a sectional view of an example of a conventional liquid crystal panel 51 used in the color liquid crystal display device of FIG. The liquid crystal panel 51 uses an active matrix system, and the liquid crystal layer 10 is sandwiched between the picture element drive circuit substrate 15 and the counter substrate 16. In the picture element drive circuit board 15, a thin film transistor (hereinafter referred to as “TFT”) 1 is formed on a glass substrate 4. The pixel electrode 2 made of ITO is connected to the drain electrode 12 of the TFT1. An alignment film 3a is laminated on the entire surface to cover the TFT1 and the pixel electrode 2.

In the counter substrate 16, the color filter 5 is formed on the glass substrate 9.
And a conductive light-shielding film 6 made of a metal thin film such as Cr is formed. The conductive light-shielding film 6 is formed on a portion of the pixel circuit board 15 other than the portion overlapping the pixel electrode 2. The conductive light-shielding film 6 is provided to reduce crosstalk between the picture elements. A protective film 7, a counter electrode 8 made of ITO, and an alignment film 3b are sequentially laminated on the entire surface of the color filter 5 and the conductive light-shielding film 6 so as to cover them. Picture element drive circuit board 15
The counter substrate 16 and the counter substrate 16 are adhered to each other with an adhesive 36.
The counter electrode 8 is connected to the electrode wiring 13 on the picture element drive circuit board 15 by a conductive connector 18. Two alignment films 3a
The above-mentioned liquid crystal layer 10 is sealed between 3 and 3b. Polarizing plates 11a and 11b are provided outside the glass substrates 4 and 9, respectively.
Is provided.

In the liquid crystal panel of FIG. 4, the backlight 14 is provided in the liquid crystal layer 10.
And through the color filter 5 and the like. Light transmitted through the liquid crystal layer 10 is controlled by changing the alignment state of liquid crystal molecules in the liquid crystal layer 10. The alignment state of the liquid crystal molecules is controlled by the voltage applied to the pixel electrode 2 via the TFT1.

(Problems to be Solved by the Invention) In the color liquid crystal display device shown in FIG. 3, a portion for displaying an image of the liquid crystal panel 51 is exposed in a large opening. Since this display part cannot be shielded, MOS
The configuration TFT1 is easily affected by static electricity. That is,
The gate insulation film of TFT1 is destroyed by the influence of static electricity, and TF
T1 may malfunction. In order to prevent the electrostatic breakdown of the gate insulating film, it is necessary to increase the thickness of the gate insulating film. In addition, a liquid crystal panel used for a television display has a problem that it is easily affected by electromagnetic noise generated in a high frequency circuit of a receiving circuit such as a tuner section. Furthermore, there is a problem that the static electricity generated on the liquid crystal panel 51 causes the voltage applied to the liquid crystal layer 10 to fluctuate and the image quality to deteriorate.

The present invention solves such a problem,
An object of the present invention is to provide a color liquid crystal display device that is not easily affected by electrostatic noise and electromagnetic noise on the liquid crystal panel.

(Means for Solving the Problems) A color liquid crystal display device of the present invention includes a pixel drive circuit substrate having a pixel electrode, a color filter, a conductive light-shielding film formed around the color filter, a counter electrode, And a counter substrate having a protective film for insulating between the conductive light-shielding film and the counter electrode, and a liquid crystal layer sealed between the pixel drive circuit substrate and the counter substrate. A liquid crystal display device, wherein the conductive light-shielding film is electrically connected to an electrode provided on the picture element drive circuit board and fixed at a ground potential via a conductive connector. The film and the counter electrode are electrically independent from each other, whereby the above object is achieved.

(Operation) In the color liquid crystal display device of the present invention, the conductive light-shielding film is electrically connected to the electrodes provided on the pixel driving circuit substrate. This electrode makes it possible to fix the potential of the conductive light-shielding film. When the potential of the conductive light-shielding film is constant, the influence on the voltage applied to the liquid crystal layer is reduced and a stable image can be obtained. Further, it is possible to prevent the influence of electrostatic noise and electromagnetic noise on the liquid crystal panel.

(Embodiment) An embodiment of the present invention will be described below.

FIG. 1 is a sectional view of a liquid crystal panel used in one embodiment of the color liquid crystal display device of the present invention. This liquid crystal panel uses an active matrix system, and a liquid crystal layer 10 is sandwiched between a picture element drive circuit substrate 15 and a counter substrate 16. In the picture element drive circuit substrate 15, the gate insulating film 23 is formed on the entire surface of the glass substrate 4, and the gate insulating film 23 is formed on the gate insulating film 23.
TFT1 is formed. The drain electrode 37 of TFT1 has IT
A pixel electrode 2 made of O is connected. The pixel electrodes 2 are formed in a matrix on the gate insulating film 23. TF
An alignment film 3a is laminated on the entire surface to cover T1 and the pixel electrode 2.

The configuration of the cross section of TFT1 will be described. Gate bus wiring is formed on the glass substrate 4, and a part of the gate bus wiring functions as the gate electrode 22. A gate insulating film 23 is formed on the entire surface to cover the gate bus wiring. A semiconductor layer 24 is formed on the gate electrode 22 via a gate insulating film 23. An etching stopper 25 is formed in the center of the semiconductor layer 24. The etching stopper 25 is provided to protect the upper surface of the semiconductor layer 24 from the etchant used to form the contact layer 26, the source electrode 27, and the drain electrode 37. Contact layers 26, 26 are formed on the semiconductor layer 24 and the etching stopper 25. A source electrode 27 and a drain electrode 37 are formed on the contact layers 26, 26, respectively. The above is the configuration of the TFT1. The above-mentioned pixel electrode 2 is connected to the drain electrode 37.

In the counter substrate 16, a color filter 5 and a conductive light-shielding film 6 made of a conductive thin film are formed on a glass substrate 9. As the material used for the conductive light-shielding film 6, in addition to metals such as Cr and Ni, carbon can be used. The conductive light-shielding film 6 is provided to reduce crosstalk between the picture elements and to prevent an increase in dark current due to light incident on the TFT 1. The conductive light-shielding film 6 is formed in a portion other than the portion overlapping the pixel electrode 2. Therefore, although the conductive light-shielding film 6 is shown discontinuously in FIG.
It is continuous in the part that does not overlap with. That is, the conductive light-shielding film 6 has a mesh shape. In addition, the conductive light-shielding film 6
The shape of may be a stripe shape. The end of the conductive light-shielding film 6 extends to the end of the glass substrate 9, and is electrically connected to the electrode 30 on the pixel drive circuit board 15 by a conductive connector 31 made of a conductive paste. The electrode 30 is further grounded or electrically connected to a metal shield lid 53 or a metal shield case 54 as shown in FIG.

A protective film 7, a counter electrode 8 made of ITO, and an alignment film 3b are formed on the entire surface of the color filter 5 and the conductive light-shielding film 6 so as to cover them.
Are sequentially stacked. The protective film 7 is made of transparent resin, SiO ₂ ,
It consists of an insulating thin film such as SiN _X. Therefore, the conductive light-shielding film 6
And the counter electrode 8 are electrically insulated. The picture element drive circuit board 15 and the counter substrate 16 are bonded to each other with an adhesive 36. The counter electrode 8 is connected to the electrode wiring 13 on the picture element drive circuit board 15 by a conductive connector 18. The above-mentioned liquid crystal layer 10 is enclosed between the two alignment films 3a and 3b. A polarizing plate 11 is provided outside the glass substrates 4 and 9, respectively.
a and 11b are provided.

The liquid crystal panel having the above structure is further assembled as a color liquid crystal display device together with the IC substrate 52, the metal shield cover 53 and the metal shield case 54 as shown in FIG.

In this embodiment, since the conductive light-shielding film 6 that functions as an electrostatic shield and an electromagnetic shield is formed on the liquid crystal panel, it is possible to prevent the generation of static electricity on the liquid crystal panel. Therefore, the fluctuation of the voltage applied to the liquid crystal layer 10 is suppressed, and a stable image is obtained. In addition, since the conductive light-shielding film 6 is formed so as to cover the TFT 1, it is
It is possible to prevent dielectric breakdown of the gate insulating film 23 of the TFT1. Furthermore, the influence of electromagnetic noise can be prevented.

FIG. 2 shows a sectional view of a liquid crystal panel used in another embodiment of the present invention. In this embodiment, in addition to the structure shown in FIG. 1, a transparent conductive film 34 made of ITO is provided on the entire surface between the glass substrate 9 and the polarizing plate 11b. The transparent conductive film 34 is electrically connected to the end portion of the conductive light-shielding film 6 by the conductive paste 32. As described above, the conductive light-shielding film 6 is formed on the pixel drive circuit board 15 by the conductive connector 31 made of a conductive paste.
It is electrically connected to the upper electrode 30. The electrode 30 is further grounded or connected to a metal shield lid 53 or a metal shield case 54 as shown in FIG.

In this embodiment, a conductive transparent conductive film 34 is formed on the surface of the liquid crystal panel.
Is formed, the generation of static electricity is more effectively prevented. Therefore, the fluctuation of the voltage applied to the liquid crystal layer 10 is further suppressed, and a stable image can be obtained. Also,
It is possible to more effectively prevent the dielectric breakdown of the gate insulating film 23 of the TFT 1 due to static electricity and the influence of electromagnetic noise.

In this embodiment, the transparent conductive film 34 is connected to the electrode 30 via the conductive light-shielding film 6 and the conductive connector 31, but
As shown by the broken line in the figure, the conductive paste 33 may be directly connected to the electrode 30. In this case, the other electrodes formed on the picture element drive circuit board 15 and the conductive paste 33 must be connected at a position where a short circuit does not occur. Further, in the present embodiment, the transparent conductive film 34 is connected to the electrode 30 to which the conductive light-shielding film 6 is connected. A pattern may be formed on the drive circuit board 15.

(Effect of the Invention) In the color liquid crystal display device of the present invention, by fixing the conductive light-shielding film electrically independent of the counter electrode to the ground potential, not only preventing crosstalk between picture elements, The liquid crystal panel display portion provided with the conductive light-shielding film acts as an electrostatic shield and an electromagnetic shield for the liquid crystal layer to suppress the effects of electrostatic noise and electromagnetic noise, and efficiently remove these noises. Therefore, it is possible to prevent fluctuations in the voltage applied to the liquid crystal layer and obtain stable image display. Moreover, electrostatic breakdown of the functional element formed on the liquid crystal panel can be prevented. Further, the color liquid crystal display device of the present invention having the above characteristics has an advantage that it can be manufactured without using a new process.

[Brief description of drawings]

FIG. 1 is a sectional view of a liquid crystal panel used in one embodiment of the color liquid crystal display device of the present invention, FIG. 2 is a sectional view of a liquid crystal panel used in another embodiment of the present invention, and FIG. 3 is a color liquid crystal display. FIG. 4 is a schematic view of a display device, and FIG. 4 is a sectional view of a liquid crystal panel used in a conventional color liquid crystal display device. 1 ... TFT, 2 ... Pixel electrodes, 3a, 3b ... Alignment film, 4,9 ...
... glass substrate, 5 ... color filter, 6 ... conductive light-shielding film, 7 ... protective film, 8 ... counter electrode, 10 ... liquid crystal layer,
11a, 11b …… polarizer, 13 …… electrode wiring, 15 …… picture element drive circuit board, 16 …… opposite board, 18,31 …… conductive connector, 2
2 ... Gate electrode, 23 ... Gate insulating film, 24 ... Semiconductor layer, 27 ... Source electrode, 30 ... Electrode, 32, 33 ... Conductive paste, 34 ... Transparent conductive film, 37 ... Drain electrode .

Claims (1)

[Scope of utility model registration request] 1. A pixel drive circuit substrate having a pixel electrode, a color filter, a conductive light-shielding film formed around the color filter, a counter electrode, and between the conductive light-shielding film and the counter electrode. A color liquid crystal display device comprising: a counter substrate having a protective film that insulates the liquid crystal layer; and a liquid crystal layer enclosed between the pixel drive circuit substrate and the counter substrate. The conductive light-shielding film is electrically connected to an electrode provided above and fixed to the ground potential via a conductive connector, and the conductive light-shielding film and the counter electrode are electrically independent Is a color liquid crystal display device.