JPH0396922A - Matrix type display device - Google Patents

Abstract

PURPOSE:To obtain necessary capacity without decreasing the aperture rate of a picture element by forming one electrode of a storage capacitor by using a transparent conductive film, connecting this electrode to the gate electrode line of the precedent stage, and using a picture element electrode as the other electrode, and forming an insulating film between both the electrodes. CONSTITUTION:On a transparent insulating substrate 10 of glass, etc., the transparent conductive film of an ITO, etc., is deposited by an EB vapor-depositing method, etc. Then this film is patterned by normal etching, etc., to form an island-shaped storage capacitor electrode 1. This is patterned by photoetching, etc., to form a gate electrode line 3. At such a time, the gate electrode line of the precedent stage and the electrode 1 of the storage capacitor are connected electrically. Therefore, the picture element of the 1st stage has no precedent stage, so a gate electrode line corresponding to a (0)th stage is formed and this and the electrode 1 of the storage capacitor of the 1st stage are connected. Then the transparent electrode of an ITO, etc., is patterned in an island shape to form the picture element electrode 8 and then the insulating film is formed between the electrodes 1 and 8.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a matrix type display device.

[Conventional technology]

A matrix type display device is usually configured such that a display material such as a liquid crystal is sandwiched between two opposing substrates, and a voltage is selectively applied to the display material. Pixel electrodes arranged in a matrix are provided on at least one of the substrates, and an active element such as a transistor is provided for each pixel electrode in order to selectively apply a voltage to these pixel electrodes.

Furthermore, in order to improve image quality, a storage capacitor is provided for each pixel.

Conventionally, there have been devices of this type as shown in FIGS. 4 to 6. FIG. 4 is a circuit diagram of a thin film transistor (hereinafter referred to as "TFTJ") used in a conventional liquid crystal display device.

In FIGS. 4 and 5, α0 is a transparent insulating substrate;
(1) is one N. pole of a storage capacitor made of a transparent conductive film such as indium tin oxide (hereinafter referred to as ITOJ) formed on this insulating substrate (11);
(2) is an insulating film, (3) is a gate electrode line, (4) is a gate insulating film, (5) is a semiconductor film, (6) is a source electrode line,
(7) is a drain electrode, (8) is a pixel electrode connected to this drain electrode, and (9) is a protective film. One electrode (1) of the storage capacitor is connected to the electrode of the storage capacitor of the other pixel so that it is always kept at a constant potential (usually ground potential) while the liquid crystal display device is in operation. connected to the external terminal of the Therefore, it is necessary to insulate the electrode (1) of the storage capacitor from the gate electrode line (3) and the source electrode line (6), and an insulating film (2) is formed after the electrode (1) is formed. Note that the pixel WL pole (8) serves as the other electrode of the storage capacitor.

Further, as other conventional examples, there are those shown in FIGS. 7 to 9. FIG. 7 is a plan view showing the main parts of another conventional example, FIG. 8 is a cross-sectional view taken along line 1-2 in FIG. 7, and FIG. 9 is an equivalent circuit thereof. The structure shown in Fig. 7 first consists of a transparent insulating substrate (1
A gate electrode line (3) is formed at 0J-. At this time, one electrode (1) of the storage capacitor is also formed at the same time and connected to the previous gate electrode line (3). The reason why one electrode (1) of the storage capacitor and the gate electrode line (3) may be connected in this way is that when scanning signals during operation, the previous scanning line, that is, the previous gate electrode line, is connected to the previous scanning line. This is because it is at ground potential except when it is being scanned.

[Problem to be solved by the invention]

Since the conventional matrix type liquid crystal display device is constructed as described above, the one shown in FIG. There are problems such as a short circuit between the storage capacitor electrode (1), the gate electrode line (3), and the source electrode line (6), resulting in a decrease in yield.

In addition, in the case shown in FIG. 7, although the number of steps for forming the storage capacitor electrode is not increased, the gate electrode line (3) in the previous stage is used as the electrode (1) of the storage capacitor, and this gate electrode line ( 3) is usually made of opaque metal, so there was a dilemma that if it was made too large, the aperture ratio of the pixel would be lowered, and if it was too small, it would not be possible to obtain the necessary capacity as a storage capacitor.

This invention was made in order to solve the conventional problems as described above, and it is possible to create a matrix that does not significantly increase the number of steps, does not reduce the aperture ratio of pixels, and does not cause a decrease in yield due to short circuits as described above. The purpose is to obtain a type display device.

[Means for deciding issues]

In the matrix type display device according to the present invention, one electrode of the storage capacitor is formed with a transparent conductive film and connected to the gate electrode line of the previous stage, the other electrode is also used as the pixel electrode, and the space between the two electrodes is By providing an insulating film, a storage capacitor is constructed.

[For production]

Since the storage capacitor constructed as described above has one electrode formed of a transparent conductive film, the aperture ratio of the pixel does not decrease. Further, since this electrode does not intersect with the gate electrode line or the source electrode line, there is no risk of short circuit.

〔Example〕

An embodiment of the present invention will be described with reference to FIGS. 1 to 3. FIG. 1 is a plan view showing the main parts of a T-fFT array substrate according to an embodiment of the present invention, FIG. 2 is a sectional view taken along the line T in FIG. 1, and FIG. 3 is an equivalent circuit diagram thereof. . In FIGS. 1 to 3, the same reference numerals as in FIGS. 4 to 9 indicate the same or corresponding parts, respectively.

First, a transparent conductive film such as ITO is deposited on a transparent insulating substrate 0* such as glass by EB evaporation or the like. Thereafter, this film is patterned by ordinary etching or the like to form an island-shaped storage capacitor electrode (1). Next, a metal such as Cr or Mo is deposited by sputtering or the like, and patterned by photoetching or the like to form a gate electrode line (3). At this time, the gate electrode line (3) at the previous stage and the electrode (]) of the storage capacitor are electrically connected. Therefore, since the first stage pixel has no previous stage, a gate electrode line corresponding to the Oth stage is formed, and this and the first stage storage capacitor electrode (1) are formed.
Connect with.

Next, a silicon nitride film (S l
3N4) or silicon oxide film (5102), and hydrogenated amorphous silicone (a-
Si:H) etc. are continuously deposited by CVD method or the like. Next, the semiconductor film is patterned into an island shape, and the insulating film (4) is further patterned. The insulating film (4) serves as a gate insulating film and an insulating film between the electrodes of the storage capacitor.

Next, a metal such as Ae or Mo is deposited by sputtering or the like,
After patterning, the source electrode line (6) and drain electrode (
7). Next, a transparent conductive film such as ITO is deposited by EB method or the like, and this is further patterned into an island shape to form a pixel electrode (8). Thereafter, Si3N4 or Si02 or the like is deposited by CVD and patterned to form a protective film (9).

In this example, an electrode (1) made of a transparent conductive film
, a pixel electrode (8), and an insulating film (4) between these electrodes constitute a storage capacitor.

A matrix type display device is constructed by sandwiching a display material such as a liquid crystal between the thus formed TFT array substrate and a counter electrode substrate having transparent conductive electrodes, color filters, etc.

In the above embodiment, a method was explained in which the gate electrode line (3) was formed after forming one N tFM (].) of the storage capacitor, but the process order was changed and the gate electrode line (3) was formed first. Even if the electrode wire (3) is formed and then one electrode (1) of the storage capacitor is formed, a storage capacitor similar to that of the above embodiment can be constructed and the same effects can be obtained.

〔Effect of the invention〕

Since the present invention is structured as described above, it produces the following effects.

Since the electrode of the storage capacitor is made of a transparent conductive film, the necessary capacitance can be obtained without reducing the aperture ratio of the pixel.

Furthermore, since the storage capacitor electrode does not intersect with the gate electrode line or the source electrode line, there is no reduction in yield due to short circuits.

[Brief explanation of drawings]

1 is a plan view showing the main parts of a TFT array substrate according to an embodiment of the present invention, FIG. 2 is a sectional view taken along line It-1 in FIG. 1, FIG. 3 is an equivalent circuit diagram thereof, and FIG. is a conventional TFT
A plan view showing the main parts of the array substrate, Figure 5 is V in Figure 4.
-V sectional view, FIG. 6 is its equivalent circuit diagram, FIG. 7 is a plan view showing the main parts of another conventional TFT array substrate, FIG. 8 is a sectional view taken along the line ■1-■ in FIG. FIG. 9 is an equivalent circuit diagram thereof. In the figure, (1) is one electrode of the storage capacitor, (
3) is a gate electrode line, (4) is an insulating film, (5) is a semiconductor film, (6) is a source electrode line, (7) is a drain electrode, (
8) is a pixel electrode, and OQ is an insulating substrate. Note that the same reference numerals in the figures indicate the same or equivalent parts.

Claims (1)

[Claims] Multiple gate electrode lines arranged in parallel on a transparent insulating substrate,
A plurality of source electrode lines intersect with the gate electrode line, a thin film transistor provided at the intersection of the two electrode lines and having a gate connected to the gate line and a source connected to the source line, and a thin film transistor connected to the drain of the thin film transistor. In a matrix type display device having pixel electrodes, one electrode is formed on the insulating substrate and is made of a transparent conductive film and connected to the previous gate electrode line; the other electrode is made of the pixel electrode; A matrix display device including a storage capacitor made of an insulating film formed between one electrode and another electrode.