JPH05289111A - Active matrix liquid crystal display device - Google Patents

Abstract

PURPOSE:To decrease the number of production stages for the active matrix liquid crystal display device having auxiliary capacitors. CONSTITUTION:A passivation film 32 consisting of a dielectric substance, such as silicon oxide, is formed atop thin-film transistors 3 and picture element electrodes 31. A counter electrode 23 consisting of ITO is formed atop the passivation film 32 above the picture element electrodes 31. The auxiliary capacitor parts are constituted by the picture element electrodes 31 and the counter electrode 23 as well as the passivation film 32 therebetween. Then, the stage for forming the dielectric thin film is saved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an active matrix liquid crystal display device.

[0002]

2. Description of the Related Art Some active matrix liquid crystal display devices have a circuit structure as shown in FIG. In this active matrix liquid crystal display device, a gate line (scanning electrode) 1 is provided in a row direction and a drain line (signal electrode) 2 is provided in a column direction, and each pixel corresponding to each intersection of the gate line 1 and the drain line 2 A thin film transistor (display driving element) 3, a pixel capacitance section 4 composed of a liquid crystal capacitance, and an auxiliary capacitance section 5 are provided for each of them, and when the thin film transistor 3 is turned on, display is performed on the pixel electrostatic capacitance section 4 and the auxiliary capacitance section 5. When data is written in the form of charges and the thin film transistor 3 is turned off, the pixels are driven by the written charges. In this case, the auxiliary capacitance section 5 is for compensating for the insufficient capacitance of the pixel capacitance section 4.

FIG. 3 shows an example of a concrete structure of such a conventional active matrix liquid crystal display device. In this active matrix liquid crystal display device, a common electrode panel 12 is superposed on a display drive panel 11 via a spacer (not shown), and the liquid crystal 1 is interposed therebetween.
It has a structure in which 3 is enclosed.

The display drive panel 11 has a glass substrate 21. An insulating film 22 made of silicon oxide, silicon nitride or the like is patterned on the upper surface of the glass substrate 21, and I is formed on a portion where the insulating film 22 is not formed.
The counter electrode 23 for the auxiliary capacitor made of TO is patterned after the insulating film 22 is formed. A dielectric thin film 24 made of silicon oxide or the like is formed on the upper surfaces of the insulating film 22 and the counter electrode 23. A gate electrode 25 made of chromium, aluminum or the like, which constitutes a part of the thin film transistor 3 shown in FIG. 2, is patterned at a predetermined position on the upper surface of the dielectric thin film 24. The gate electrode 25 is connected to the gate line 1 shown in FIG. A gate insulating film 26 made of silicon oxide is formed on the entire upper surface of the dielectric thin film 24 including the gate electrode 25. A semiconductor thin film 27 made of amorphous silicon or polysilicon is patterned on the upper surface of the gate insulating film 26 corresponding to the gate electrode 25 and its periphery. Semiconductor thin film 2
A drain electrode 28 and a source electrode 29 made of chromium, aluminum, or the like are patterned on the left and right sides of the upper surface of 6. The drain electrode 28 is connected to the drain line 2 shown in FIG.

The counter electrode 2 near the semiconductor thin film 26
A pixel electrode 31 made of ITO is patterned on the upper surface of the gate insulating film 26 above 3 before forming the semiconductor thin film 26 and before forming the drain electrode 28 and the source electrode 29. The pixel electrode 31 is connected to the source electrode 29. Then, the pixel electrode 31,
The opposing electrode 23 and the dielectric thin film 24 between them constitute the auxiliary capacitance section 5 shown in FIG. Semiconductor thin film 2
6, drain electrode 28, source electrode 29, pixel electrode 31
A passivation film 32 made of silicon oxide or the like is formed on the entire upper surface of the gate insulating film 26. An alignment film 33 is formed on the upper surface of the passivation film 32.

The common electrode panel 12 has a glass substrate 41. A common electrode 42 made of ITO is patterned on the lower surface of the glass substrate 41. An alignment film 43 is formed on the entire lower surface of the glass substrate 41 including the common electrode 42. Then, the pixel electrode 31 of the display drive panel 11,
The common electrode 42 of the common electrode panel 12 and the liquid crystal 13 between them constitute the pixel capacitance section 4 shown in FIG.

[0007]

However, in such a conventional active matrix liquid crystal display device,
Looking at the display drive panel 11, the step of forming the insulating film 22, the step of forming the counter electrode 23, the step of forming the dielectric thin film 24, the steps of forming the thin film transistor 3 including the gate electrode 25 and the pixel electrode 31, and the passivation film 3 are described.
There is a problem that the number of manufacturing steps is large, such as the step of forming No. 2 and the step of forming the alignment film 33. An object of the present invention is to provide an active matrix liquid crystal display device capable of reducing the number of manufacturing steps.

[0008]

The present invention provides a pixel electrode,
In an active matrix liquid crystal display device in which liquid crystal is sealed between a display drive panel having a display drive element and a passivation film covering them and a common electrode panel having a common electrode, the passivation film is provided on the pixel electrode. Along with the formation, a counter electrode is formed on the passivation film, and the passivation film serves as a dielectric for a storage capacitor.

[0009]

According to the present invention, the counter electrode of the pixel electrode is formed on the passivation film so that the passivation film serves as a dielectric thin film. The step of forming the thin film can be omitted, and accordingly, the number of manufacturing steps can be reduced accordingly.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 in which the same names as in FIG. 2 are assigned the same reference numerals shows the main part of an active matrix liquid crystal display device according to an embodiment of the present invention. In this active matrix liquid crystal display device, the structure of the display drive panel 11 is different from that of the conventional device shown in FIG. 2, and therefore the structure of the display drive panel 11 will be described below.

A predetermined position on the upper surface of the glass substrate 21 is patterned with a gate electrode 25 made of chromium, aluminum or the like. A gate insulating film 26 made of silicon oxide is formed on the entire upper surface of the glass substrate 21 including the gate electrode 25. A semiconductor thin film 27 made of amorphous silicon or polysilicon is patterned on the upper surface of the gate insulating film 26 corresponding to the gate electrode 25 and its periphery. Drain electrodes 28 made of chromium, aluminum, or the like are formed on the left and right sides of the upper surface of the semiconductor thin film 26.
And the source electrode 29 is patterned. A pixel electrode 31 made of ITO is patterned on the upper surface of the gate insulating film 26 in the vicinity of the semiconductor thin film 26 after the semiconductor thin film 26 is formed and before the drain electrode 28 and the source electrode 29 are formed. .. The pixel electrode 31 is connected to the source electrode 29. Semiconductor thin film 2
6, drain electrode 28, source electrode 29, pixel electrode 31
A passivation film 32 made of a dielectric material such as silicon oxide is formed on the entire upper surface of the gate insulating film 26. Passivation film 3 above pixel electrode 31
A counter electrode 23 made of ITO is formed on the upper surface of 2. An alignment film 33 is formed on the entire upper surface of the passivation film 32 including the counter electrode 23. The pixel electrode 31, the counter electrode 23, and the passivation film 32 therebetween form the auxiliary capacitance section 5 shown in FIG.

As described above, in this active matrix liquid crystal display device, the counter electrode 23 of the pixel electrode 31 is provided on the passivation film 32 and the passivation film 3 is formed.
2 has a role as a dielectric thin film, so that FIG.
Compared with the conventional one shown in FIG. 2, the step of forming the insulating film 22 and the step of forming the dielectric thin film 24 can be omitted,
Therefore, the number of manufacturing steps can be reduced accordingly. Moreover, since the formation of the thin film transistor 3 is completed before forming the counter electrode 23, the thin film transistor 3
It is possible to inspect the electrical characteristics at the time when the formation of the counter electrode is completed. Therefore, if the inspection result determines that the product is defective, it can be discarded before the formation of the counter electrode 23. It is also possible to reduce the overall cost.

In the above embodiment, the thin film transistor 3 is of the inverted stagger type, but it goes without saying that it may be of any other type.

[0014]

As described above, according to the present invention, since the passivation film serves as a dielectric thin film which constitutes the auxiliary capacitance portion, at least the dielectric film can be used as compared with the conventional one. The step of forming the thin film can be omitted, and accordingly, the number of manufacturing steps can be reduced accordingly.

[Brief description of drawings]

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

FIG. 2 is a diagram showing a circuit configuration of a conventional active matrix liquid crystal display device.

FIG. 3 is a sectional view showing an example of a specific structure of a conventional active matrix liquid crystal display device.

[Explanation of symbols]

 3 Thin Film Transistor (Display Driving Element) 11 Display Driving Panel 12 Common Electrode Panel 13 Liquid Crystal 23 Counter Electrode 31 Pixel Electrode 32 Passivation Film 42 Common Electrode

Claims (1)

[Claims] 1. An active matrix liquid crystal display device in which liquid crystal is sealed between a display drive panel including a pixel electrode, a display drive element and a passivation film covering them, and a common electrode panel including a common electrode. Forming the passivation film on the pixel electrode, and forming a counter electrode on the passivation film,
An active matrix liquid crystal display device, wherein the passivation film is a dielectric for a storage capacitor.