JPS63253331A - Electrooptical device and its production - Google Patents

Abstract

PURPOSE:To attain the excellent display performance and to facilitate production by providing a place, in which a drive electrode and a signal line electrode overlap, on the end part of the opening of the signal line electrode and exposing from the back of a transparent substrate. CONSTITUTION:The place in which the signal line electrode 3 and the liquid crystal drive electrode 5 overlap is provided less than 3mum the both sides of the opening of the signal line electrode 3 and a signal electrode line. Since a nonlinear resistance film 4 can be formed transparent much the same as an insulating film made of silicon, oxygen, nitrogen and carbon, the fully formed film 4 including the lower surface of the liquid crystal drive electrode 5 being a transparent conductive film never affects display. In a stage where exposure and development are carried out from the back of a transparent insulating plate 1, the exposure quantity is set higher than a normal case, so that a photoresist 10 can be exposed up to the inside of the signal line electrode 3. Meanwhile, a photomask stage is done only once, and no mask matching is needed. Thus an active matrix panel using a nonlinear resistance element can be easily produced, and moreover picture quality identical to that generated on a CRT can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to an electro-optical device such as a liquid crystal display device in which a nonlinear element is provided for each pixel, and a method for manufacturing the same.

[Summary of the Invention] The present invention provides an electro-optical device using a nonlinear resistance film and a method for manufacturing the same, in which an overlapping portion of a drive electrode and a signal line electrode is provided at the end of an opening of the signal line electrode, and a transparent substrate is By performing exposure from the back side, the display performance is excellent and the manufacturing method is easy.

[Prior art] Liquid crystal display as a small, lightweight, low-SaW display device
! 4r11 has been put into practical use. In recent years, for the purpose of increasing the display information ffi at the H position of this type of display, research has been carried out on liquid crystal display devices using MIM type nonlinear elements such as diodes and metal-seamless film-metal structures. FIG. 4 is an equivalent circuit diagram of a matrix liquid crystal display H@ using a conventional nonlinear element. In FIG. 4, 11 is a group of row electrodes, and 2 is a group of column electrodes.1 At the intersection of the 0th row electrode and the column electrode, which usually consist of 100 to 1000 electrodes each, a liquid crystal 13 and a nonlinear element 14 are connected in series. It is formed. When a voltage is applied across these ends to drive the liquid crystal 13, a sudden change in resistance of the nonlinear element 14 consisting of an equivalent resistance and an equivalent capacitance RNL, CNL causes the rise characteristics of the liquid crystal 13 consisting of an equivalent resistance and an equivalent capacitance R1c, C1c to change as follows. The slope is much steeper than when the liquid crystal is driven alone.

In an active matrix liquid crystal display*at using such a nonlinear element, CNL is sufficiently smaller than C1c (
This is necessary for the voltage pulse applied to the unit pixel to be applied to the nonlinear element to cause a large resistance change in Rlc, and to be written to Clc as the liquid crystal drive voltage. In conventional MIM, the thickness of the insulating film is 100~5.
Since it uses materials such as tantalum oxide with a thickness of 100 angstroms, it has a large capacitance per unit area, making it smaller than a normal pixel (100 angstroms).
In the case of a size of 0 to 500J1m2), the area of the nonlinear element must be several μm square or less, and the alignment accuracy of the gap in element formation must be several μm square or less. The alignment accuracy must be within several μrn, and therefore a device such as an aligner capable of precise alignment is required, which has been difficult to put into practical use due to manufacturing costs, yields, etc. Furthermore, in conventional liquid crystal display devices using MIM, the manufacturing process is complicated, requiring two or more photomask steps, and the insulating film is thin, resulting in insufficient reliability. there were.

[Problems to be Solved by the Invention] Therefore, this invention was made to solve these conventional drawbacks, and the first purpose is to provide a nonlinear resistance element with excellent reliability and display quality. A second purpose is to provide a method for manufacturing an electro-optical device using a nonlinear element, which can significantly reduce the number of manufacturing steps.

[Means for Solving the Problems] In order to solve the above problems, the present invention performs self-aligned mask alignment using the signal line electrode as a mask using light incident from the back side, and eliminates the wraparound light at the edge of the mask. The transparent conductive film, which is the drive field, is selectively removed, with the area exposed in step 2 as the active area of the nonlinear resistance element.

[Function] By using the signal line electrode as a mask and performing self-aligned mask alignment using incident light from the back side as described above, it is possible to form the substrate of a liquid crystal display device without precise alignment, and the liquid crystal drive electrode and Since the area of the active region of the nonlinear resistance element can be reduced by setting the overlap of the signal electrodes within 3 μrn, the nonlinear resistance element connected in series with the liquid crystal can be operated by effectively applying a voltage from the outside.

[Example] The first txi shows an example of a cross-sectional structure of a matrix liquid crystal display device according to the present invention. The substrate includes a signal line electrode 3 made of a metal such as chromium or aluminum on a transparent insulating substrate l made of glass, a nonlinear resistive film 4 thereon, and an ITO film selectively formed on the nonlinear resistive film 4. It consists of a liquid crystal drive electrode 5 which is a transparent conductive film such as (indium tin oxide).

The liquid crystal G is sandwiched between a transparent insulating substrate 2 and a transparent insulating substrate 1 on which a tα crystal drive electrode 7 made of a transparent conductive film is formed. When the liquid crystal 6 is a TN field effect liquid crystal, polarizing plates 8.9 are provided on the back surfaces of the transparent insulating substrate 1 and the transparent insulating substrate 2, which are perpendicular to each other. The composition of the nonlinear resistor M4 is silicon, M1! : Contains more silicon than an insulating film made of nitrogen, carbon, etc. FIG. 2 shows an example of the planar structure of the substrate (substrate 1 in FIG. 1) on the side on which the nonlinear resistive film 4 of the matrix liquid crystal display device of the present invention is provided. The overlapping part of the signal line electrode 3 and the liquid crystal drive electrode 5 is the opening of the signal line electrode 3 and the signal line electrode 3. l! They are provided along the polar line within 3 μm from both ends of the polar line. The nonlinear resistance film 4 can be formed to be almost transparent like an insulating film made of silicon, oxygen, nitrogen, carbon, etc., so even if it is formed on the entire surface including the lower surface of the liquid crystal drive electrode 5, which is a transparent conductive film, it will not display. There is no problem at all. Here, since there are liquid crystal drive electrodes 5' between adjacent signal line electrodes, there is a possibility that crosstalk may occur between them. This situation is shown in the equivalent circuit diagram of the panel of the present invention in FIG.
Since it is divided by CI and C2, the nonlinear resistance film does not become conductive. Further, the voltage applied to the liquid crystal drive electrode 5' via the liquid crystal layer is tCO and C! Or it is divided into C2. Since the area is much smaller than the area of the liquid crystal drive electrode 5 in the display section, the ratio of CO and 01 is the pixel capacity ratio CLC/
Since it is much smaller than Ci, the nonlinear resistive film in this part does not become conductive with the voltage applied to the iα product drive electrode 5°, so crosstalk between adjacent signal electrode lines can be ignored. .

FIGS. 3(a) to 3(cl) are cross-sectional views of one embodiment showing the order of manufacturing steps of the substrate of the matrix liquid crystal display device of the present invention.
A process of selectively forming signal line electrodes 3 made of metal such as chromium or aluminum on a transparent insulating substrate l (see Fig. 3).
a)) After successively depositing the nonlinear resistor M4 and the transparent conductive film 5, a photoresist 10 is applied and exposed from the back side of the transparent insulating substrate 1 (FIG. 3(b)), and the photoresist 10 is developed. Figure 3(C)), photoresist lO
The transparent conductive layer 1115 is selectively removed using the mask as a mask (FIG. 3(d)). In the step of exposing and developing from the back surface of the transparent insulating substrate 1, the exposure amount is set to be higher than generally used so that the photoresist 10 is exposed to the inside of the pattern of the signal line electrodes 3. The normally possible overexposure length is 0.5 to 3 [mu][n]. In the embodiments of the present invention described above, the photomask process is performed only once, and mask alignment is not required.

[Effects of the Invention] As described above, according to the present invention, an active matrix panel using non-linear resistance elements can be manufactured by only one photomask process without the need for mask alignment. Manufacturing yield can be improved by simplifying the manufacturing process. The present invention has the remarkable effect of being able to provide a flat panel with image quality comparable to that of a CRT at a low cost.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing an embodiment of an active matrix device according to the present invention, FIG. 2 is a plan view showing an embodiment of an active matrix device am according to the present invention, and FIGS.
(d) is a cross-sectional view of another embodiment showing the manufacturing process order of the substrate of the matrix device of the present invention, and FIG. 4 is a diagram showing an equivalent circuit of an active panel using a conventional non-linear resistance element. FIG. 5 is a diagram showing an equivalent circuit of the active panel of the present invention. DESCRIPTION OF SYMBOLS 1... Lower substrate, 2... Upper substrate, 3... Signal line electrode, 4... Nonlinear resistance film, 6... Liquid crystal drive electrode,
G...More than liquid crystal (however, 1 power) - "'

Claims (2)

[Claims] (1) Two opposing substrates, an electro-optic material layer sandwiched between the substrates, a driving electrode provided on each of the two opposing substrates, and a drive electrode provided for each pixel on at least one of the substrates. It consists of a nonlinear resistance film sandwiched between a first drive electrode and a signal line electrode, and the first drive electrode is located within 3 μm from the end of the signal line electrode in an opening provided in the signal line electrode surface. An electro-optical display device characterized in that the display device overlaps two-dimensionally along the . (2) a) First step of selectively forming a signal line electrode made of a first conductive film and having an opening on a transparent insulating substrate c) Third step of depositing a transparent conductive film d) Applying photoresist After that, a fourth step of selectively removing the transparent conductive film by exposing and developing the transparent insulating substrate from the back surface and using the planar shape of the photoresist as a mask.