JPS62278706A - Manufacture of pattern sheet - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] 3. Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a method for producing a plastic film with a patterned conductive layer used as an electrode of a liquid crystal display device. .

(Prior Art and Problems) Electrode substrates for liquid crystal displays are changing from conventional glass to plastic films, but unlike glass, plastic films undergo dimensional changes due to environmental changes, and cannot be manufactured using the same manufacturing methods as glass. Currently, various plastic films are beginning to be used as electric boards,
The biggest problem in the manufacturing process is how to reduce dimensional expansion and contraction of plastic films, whose usage changes due to environmental changes, and manufacture them into optical functional parts that require high precision. The present inventors have conducted various studies focusing on how to satisfy the dimensional accuracy required for an optical electrode substrate when using a -axis stretched polyester film as an electrode cover plate for a liquid crystal display element. As a result, we have arrived at the present invention.

(Means for Solving the Problems) The present invention provides a method for manufacturing a pattern for a liquid crystal display made of a plastic substrate, which takes into account dimensional changes due to the environment when uniaxially stretched polyester films are used for the upper and lower substrates. Before etching the transparent conductive layer of the transparent conductive plastic film into a predetermined pattern, the transparent conductive plastic film is annealed at high temperature and then exposed to higher humidity than standard conditions to accelerate etching. This is a method for producing a patterned sheet, characterized in that the dimensions are achieved under standard conditions.

A uniaxially stretched film is not limited to one that has been stretched strictly in one direction, but includes one that has been stretched in two directions. Rather, from the viewpoint of the overall strength of the film, it is better to use a pseudo-axially stretched film that is biaxially stretched and has different stretching ratios between the two wheels.

The material of the uniaxially stretched film used in the present invention is not particularly limited, but polyethylene terephthalate is currently preferred.

Using a -axis stretched film like this, the angles formed by the sides at the four corners of the rectangular substrate with respect to the orientation axis are 45°.
By positioning the film within ±2.5° and cutting it out (Japanese Patent Application No. 60-197236), or depending on the pattern design, by cutting it out at right angles to the MD and TD force directions of the film. It is possible to obtain a display screen without distortion or shading similar to that of a liquid crystal display element using .

In this way, when patterned electrodes for liquid crystal display are formed on the cut out film sheet, several steps are performed. When using a uniaxially stretched polyester film, it is necessary to selectively dissolve and remove low molecular weight polyester precipitates to create a film with reduced light transmittance (
JP-A-60-175031> For these reasons, the process after cutting out is slightly different from that of a conventional glass substrate, and is as shown in FIG. Particularly when handling flexible substrates such as films, opening reference holes after cleaning for processes such as film transport and exposure makes handling easier by using them for positioning the substrate in subsequent processes.
It must be handled with great precision. However, the standard system conditions set in relation to the final product are as follows: 25°C, for example.
After stabilizing the film at 150% RH,
It is necessary to leave a reference hole open. In particular, the accuracy of the pattern is determined by the time when drilling the aUL hole, the exposure and printing of the pattern,
It is necessary that the film be dimensionally the same at the last inspection. In the case of a film, unlike a glass substrate, the rate of shrinkage due to heat, expansion due to temperature, and expansion due to humidity is large, so when etching is performed with high precision, sufficient consideration must be given to changes in the dimensions of the film.

There are three types of dimensional changes in polyester film: ■thermal shrinkage, ■temperature expansion, and ■temperature expansion. ■Irreversible change■,■
is an irreversible change. Therefore, it is necessary to consider the manufacturing method in consideration of these dimensional changes.

The present inventors have studied in detail the heat loss rate, temperature expansion coefficient, temperature expansion coefficient, and humidity expansion coefficient of the uniaxially stretched polyester film used, and have determined that the dimensional difference when changing from one environment to another. These factors were reflected in the patterning process by determining the time it takes to stabilize (relaxation time).

As a result, the dimensional recovery time after annealing and cleaning is 25°C.
It was found that aging for about 4 hours at 150% and 1.5 hours at 180% at 25°C is the time required to recover to the stable dimensions at 25°C and 150%. That is, it was found that the relaxation time was significantly shortened by placing it under high humidity. Therefore, it is sufficient to measure the relaxation time under high humidity through a preliminary experiment and determine the time to maintain the substrate under high humidity. Standard conditions are set as appropriate, but in general they are 25°C, 150% R, H.

Therefore, the explanation for that case is as above. If reference holes are then drilled, the distance accuracy between the holes can be maintained within ±10 μm. In addition, although there are processes in which the film is immersed in water such as developing, etching, and resist stripping, the film is dried and then aged for at least 4 hours under the test environment conditions (25°C, 150%). It is necessary to keep it. By performing such processing, the dimension measurement for inspection can be evaluated with an accuracy of ±10 μm.

(Effects of the Invention) The main point of the present invention is that it has developed a processing method that takes into account the dimensional change of the film when processing a patterned sheet for liquid crystal display using a uniaxially stretched polyester film. Processing and inspection can be performed with an accuracy of ±10 μm.

If manufacturing and inspection can be performed using the process of the present invention, patterned products with almost no dimensional variation can be obtained. If a patterned product is manufactured by simply returning the temperature to standard conditions for dimensional recovery after aging, the product may have dimensions that are significantly different from the design values, or there may be variations in dimensional accuracy between lots. However, according to the present invention, products of constant quality can be manufactured in a relatively short time, although uniformity in performance as a liquid crystal display element cannot be ensured.

[Brief explanation of drawings]

Figure 1 is a flow sheet of the main manufacturing process of pattern sheets.

Claims (1)

[Claims] Prior to etching the transparent conductive layer of the transparent conductive plastic film into a predetermined pattern, the transparent conductive plastic film is annealed at high temperature and then exposed to higher humidity than standard conditions to accelerate the etching process under standard conditions. A method for producing a patterned sheet, characterized in that the dimensions of the patterned sheet are reached.