JPH0239130A - Liquid crystal display device - Google Patents

Abstract

PURPOSE:To suppress the variation of a source signal and to prevent the generation of crosstalk by inserting a parasitic capacity reducing insulating film into an intersecting part between an additional capacity electrode and a source bus line connected to the source electrode of a thin film transistor(TFT). CONSTITUTION:A gate electrode 2 is formed on an insulating substrate 1, a transparent conductive film mainly consisting of indium oxide is formed on the surface of the electrode 2 and then the conductive film is photoetched to pattern a Cs electrode 10. Then, a gate insulating film 3 consisting of SiNx is formed and a semiconductor film 4 consisting of a-Si and insulating film 5 consisting of SiNx are successively formed. Consequently, the capacity reducing insulating film 11 can be formed on the intersecting part between the semiconductor film 4, the insulating film and the Cs (additional capacity) electrode 10 and the source bus line 7' by patterning the films 4, 5. Consequently, capacity generated at the intersecting part between the Cs electrode 10 and the source bus line 7' can be reduced and the variation of a source signal can be suppressed, so that the generation of crosstalk can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to an inverted starch type thin film transistor (hereinafter referred to as "T") using amorphous silicon as a semiconductor film.
The present invention relates to a liquid crystal display element having a liquid crystal cell substrate formed by arranging an additional capacitance electrode (referred to as "PT"), an additional capacitance electrode, and a picture element electrode in a matrix.

<Prior Art> An example of a liquid crystal display device that uses TPT as an address element to perform matrix display is shown in FIGS. 4, 5, and 6. This liquid crystal display device has a gate electrode 2 on an insulating substrate 1. Gate insulating film 3. Amorphous silicon (a-
5i ] I! '4, absolutely Rf'A 51 n"-a-
3i membrane6. Source/drain electrode7. Picture element electrode 8. It is formed by sequentially laminating protective films 9. Here, in order to improve the picture element electrode potential retention characteristic, C8 is formed to form an additional capacitor (hereinafter referred to as R (sI+)) in parallel with the liquid crystal capacitor.
An electrode 10 is provided directly below the picture element electrode 10.

In the conventional structure, a CS is formed in parallel with the liquid crystal capacitor in order to improve the pixel potential retention characteristics, but the capacitance generated between the C5 electrode and the source bus line causes fluctuations in the source signal. Crosstalk occurs. In order to improve this, there is a method to increase the thickness of the gate insulating film or to use a material with low conductivity for the gate insulating film, but in that case, the gap between the C5 electrode and the pixel electrode is Capacity becomes smallerC
5, it no longer functions sufficiently.

Means for Solving the Problems> The present invention further provides an insulation film between the C8 electrode and the pixel electrode by adding an insulating film only to the intersection of the source bus line connected to the C5 electrode and the source electrode of the TFT. C5 formed
TET that makes it possible to reduce the capacitance generated at the intersection of the C5 electrode and the source bus line without reducing the capacitance of
This is a liquid crystal display device characterized by having a drive type liquid crystal cell substrate.

<Operation> The above structure reduces the capacitance generated at the intersection between the C5 electrode and the source bus line, suppresses fluctuations in the source signal, and thereby prevents crosstalk from occurring.

<Example> An example of the present invention will be described using FIGS. 1, 2, and 3. Fig. 1 is a configuration diagram showing the arrangement structure of TPT, Fig. 2 is a sectional view taken along line AA in Fig. 1, and Fig. 3 is a sectional view taken along line B-B in Fig. 1.
FIG. Ti is deposited on an insulating substrate 1 made of glass by sputtering.

Mo, W, Ta, etc. are formed and patterned by photo-etching to form the gate electrode 2.

Next, a transparent conductive film containing indium oxide as a main component is formed by sputtering or electron beam evaporation, and this is patterned by photo etching to form a C8 electrode 10. Next, a gate insulating film 3 made of SiNx is formed by plasma CVD, and then a semiconductor film made of a-3i and an insulating film made of SiNx are formed and patterned by photo-Φ etching. Membrane 4. Insulating film 5 and Cs? [An insulating film 11 for capacitance reduction is formed at the intersection of the pole 1o and the source bus line.

Next, a semiconductor film 6 is formed by forming an n''-a-5i semiconductor film by plasma CVD and patterning it by photo-etching.Next, Ti, Mo, W, etc. are formed by sputtering and photonumbered. A transparent conductive film containing indium oxide as a main component is formed by sputtering or electron beam evaporation.
A substantially rectangular picture element electrode 8 is formed by patterning by etching. Next, Si
A protective film 9 made of Nx is formed. The picture element electrodes 8 are arranged in a matrix on the insulating substrate 1, and a TPT is arranged corresponding to each picture element chamber (iB).The drain electrode of the TPT is connected to one end of the picture element electrode 8, and the source electrode and the gate pole 2 are connected to the source bus line and the gate pass line, respectively.As described above, the TPT substrate for a liquid crystal display cell has the insulating film 11 for capacitance reduction formed at the intersection of the c8i pole and the source bus line. Incidentally, in this embodiment, the C3 electrode 10 is formed of a transparent conductive film, but it may be formed using the same material as the gate electrode 2 when forming the gate electrode 2.

A matrix display type liquid crystal display device can be obtained by stacking and integrating the TPT substrate and the cell substrate on which the other counter electrode is formed, and filling the gap with a liquid crystal material.

A two-layer structure consisting of the SiNx layer of the gate insulating film 3 and the insulating film 11 for capacitance reduction is interposed between the CS electrode 10 and the source bus line 7. Therefore, the C8 electrode 10 acts as an electrode for additional capacitance with the picture element electrode 8, but does not capacitively couple with the source bus line 7', and does not affect the signal on the source bus line 7'. Not at all.

<Effects of the Invention> As described above, the C8? Fluctuations in the source signal due to the capacitance between the CSI pole and the source bus line can be suppressed without changing the additional capacitance between the iE pole and the picture element electrode, and crosstalk can be prevented from occurring.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a plan view of a liquid crystal display cell substrate for explaining an embodiment of the present invention, and FIG. 2 is a sectional view taken along line A-X in FIG. 1. FIG. 3 is a sectional view taken along line B-X in FIG. FIG. 4 is a plan view of a conventional liquid crystal display cell substrate. FIG. 5 is a sectional view taken along line XX in FIG. 4. FIG. 6 shows a YY' cross-sectional view of FIG. 4. DESCRIPTION OF SYMBOLS 1... Insulating substrate, 2... Gate electrode, 3°... Insulating film, 4, 6... Semiconductor film, 7... Source-in electrode, 8... Picture element electrode, 9...・Protective film, 1 electrode. , 11 Dore 0...C5 Agent Patent Attorney Takeshi Sugiyama (and 1 other person) also 2? Kotaka 3 figure $1 figure 11!4 figure

Claims (1)

[Claims] 1. In a liquid crystal display device in which a thin film transistor, a picture element electrode connected to the drain electrode of the thin film transistor, and an additional capacitance electrode forming an additional capacitance between the picture element electrode are arranged in a matrix on a liquid crystal cell substrate. . A liquid crystal display device, wherein an insulating film for reducing parasitic capacitance is interposed at the intersection of the additional capacitance electrode and the source bus line connected to the source electrode of the thin film transistor.