JP2003195272A - Electrode board for liquid crystal display - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrode board for a liquid crystal display which can be easily manufactured, by simplifying as much as possible a structure of an electrode board advantageous in the accuracy of the whole display, in the manufacture of the electrode board for the liquid crystal display using a plastic substrate and forming switching elements and a transparent electrode for driving pixels on the same board. <P>SOLUTION: A transparent colored pattern layer 2 is provided on the plastic substrate 6 without a barrier layer thereon, a switching element 4 and the transparent electrode 5 for driving the pixel are formed thereon across a transparent coating layer 8. The transparent coating layer is an organic or inorganic electrically insulating gas shut-off film, and has a function of shutting off ionic impurities. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an electrode plate for a liquid crystal display device using a plastic substrate.

[0002]

2. Description of the Related Art Conventionally, a structure of a color liquid crystal display device using an active matrix type liquid crystal display device electrode plate in which switching elements such as thin film transistors and transparent electrodes for driving pixels are regularly arranged has a transparent colored pattern layer. Another substrate having a (color filter; abbreviated as CF hereinafter) was bonded to the electrode plate under accurate alignment with the liquid crystal sandwiched therebetween.

However, in recent years, when finer image display is realized on a large-sized panel and bright high-quality display is demanded, the accuracy of bonding two substrates constituting the panel becomes higher and higher. A slight misalignment in bonding, which is required, causes a situation in which the aperture ratio of the pixel is significantly reduced.

In order to solve the above problems, it is assumed that the electrodes including the switching elements and the CFs defining the display areas of the pixels are accurately aligned by photolithography.
There is a proposal to form it on a single substrate to eliminate the influence of the accuracy of bonding with a counter substrate in the panel manufacturing process. In this proposed form, for example, a switching element is formed on a substrate, then CF is formed, and a pixel driving transparent electrode is drawn out to the CF surface through a through hole to form an electrode plate.

However, to make the electrode plate having the above structure,
Not only is it difficult to ensure the reliability and reliability of the electrical connection through the through hole, but the manufacturing process is complicated. Therefore, as another simple form in which an electrode including a switching element and a CF defining a display area of a pixel are formed on one substrate, as shown in Japanese Patent Laid-Open No. 10-239680, A method of forming CF first, then interposing an overcoat, and forming a switching element and a pixel driving transparent electrode on the CF has been proposed and is considered to be promising. FIG. 2 is a cross-sectional view schematically showing this embodiment, in which a color filter (2) is provided on a glass substrate (1) and a switching element (4) and a pixel driving transparent layer are provided through an overcoat (3). The electrode (5) is formed.

In all of the above, a transparent glass substrate is generally used as the substrate, and it is premised that the process temperature is 200 ° C. or higher. However, in recent years, in order to fulfill the demand for a light, thin display device that does not break,
Liquid crystal display devices using plastic substrates have begun to be developed. Needless to say, high display quality is required for such new products as well, and both materials and processes are being developed in order to realize colorization with high precision and high aperture ratio even on plastic substrates.

Due to the flexibility of the plastic substrate, it is possible to realize a display device having a function which the glass substrate does not have, but there are many problems in resistance to heat, force, chemicals and the like. Although the development of materials can improve them, in particular, in order to manufacture a highly accurate display device, measures more than glass substrates are required.

That is, an electrode including a switching element and a CF for defining a display area of a pixel are formed on one substrate on the premise of accurate alignment by photolithography, and are bonded to a counter substrate in a panel manufacturing process. The above-mentioned promising method of eliminating the influence of the accuracy of the above, in particular, forming CF on the substrate first, then interposing the transparent covering layer, and forming the switching element and the pixel driving transparent electrode thereon. In order to realize the above with a plastic substrate, more measures than a glass substrate are required.

When a plastic substrate is applied to a liquid crystal display device, in an example in which a simple matrix drive liquid crystal display device of STN type or the like is used for both monochrome display and color display, moisture is first applied to the surface of the plastic substrate. It is common to provide a barrier layer for preventing the entry of gas and gas, and the substrate subjected to such treatment is positioned as the substrate. FIG. 3 schematically shows the structure of a plastic substrate used in a liquid crystal display device. The barrier layer (7) is formed on the front and back surfaces of the plastic substrate (6).
Is provided.

Further, for example, as shown in FIG. 2, when an overcoat is interposed on CF and a switching element and a pixel driving transparent electrode are formed on the CF, the function of the overcoat is to flatten the surface. Not only is it intended to prevent the impurity ions from CF from affecting the characteristics of the switching element as a semiconductor or penetrating into the liquid crystal side to cause a problem.

As described above, Japanese Patent Laid-Open No. 10-239
When the method disclosed in Japanese Patent No. 680 is applied to an electrode plate for a liquid crystal display device of a plastic substrate, first, a plastic substrate with a barrier film that secures a barrier property against moisture and gas as a substrate is supplied, and then CF Is formed under the process conditions adapted to the characteristics of the plastic substrate, then the overcoat is interposed, and the switching element and the pixel driving transparent electrode are formed on the overcoat. When the process steps from the original substrate are also included. It has become long and there has been a demand for shortening the process.

[0012]

SUMMARY OF THE INVENTION The present invention provides a liquid crystal display device electrode plate in which a switching element and a pixel driving transparent electrode are formed on the same substrate by using a plastic substrate, and an entire display device is provided. The electrode plate with a structure that is advantageous in terms of accuracy should be as simple as possible,
An object is to propose an electrode plate for a liquid crystal display device that can be easily manufactured.

[0013]

According to the present invention, a transparent coloring pattern layer is provided on a plastic substrate on which a barrier layer is not provided, and a switching element and a pixel driving transparent electrode are provided on the transparent coloring pattern layer. The electrode plate for a liquid crystal display device is characterized in that and are formed.

Further, in the present invention, in the electrode plate for a liquid crystal display device according to the above invention, the transparent coating layer is an organic or inorganic electrically insulating gas blocking film and has a function of blocking ionic impurities. Is an electrode plate for a liquid crystal display device.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION An electrode plate for a liquid crystal display device according to the present invention will be described below based on one embodiment thereof. FIG. 1 is a sectional view schematically showing an embodiment of an electrode plate for a liquid crystal display device according to the present invention. As shown in FIG. 1, on a plastic substrate (6) not provided with a barrier layer,
Transparent colored pattern layer (color filter (CF)) (2)
Is provided and the switching element (4) and the pixel driving transparent electrode (5) are formed on the transparent coating layer (8) via the transparent coating layer (8), and is transparent on the other surface of the plastic substrate (6). A covering layer (8) is provided.

The transparent coating layer (8) is a barrier layer for preventing moisture and oxygen gas from entering the plastic substrate surface, and CF.
When a switching element or the like is placed on the liquid crystal to drive the liquid crystal, it has two functions of a protective layer that prevents the impurity ions from seeping out from CF. The material of the transparent coating layer may be the same as the material for forming the gas barrier layer on a general plastic substrate. To reduce the gas permeability mainly to water and oxygen, for example, acrylic resin, polycarbonate resin,
Organic layers such as fluororesin, SiOx, AlOx, Si ₃
A multilayer film with an inorganic layer such as N ₄ may be used. A combination with an overcoat material applied to CF on a general glass substrate is also possible.

The plastic substrate (6) has a thickness of 100 to
There is no particular limitation as long as it is a polycarbonate, polyether sulfone, polyarylate, polyolefin or the like having a thickness of about 400 μm and various properties such as heat resistance and optical properties are satisfied for a liquid crystal display device. The transparent colored pattern layer (color filter (CF)) (2) is
The same characteristics as those formed on the glass substrate are required, but those satisfying the process constraint conditions and the like due to the characteristics of the substrate are preferable.

[0018]

According to the present invention, a transparent colored pattern layer is provided on a plastic substrate on which a barrier layer is not provided, and a transparent coating layer having two functions of a barrier layer and a protective layer provided thereon is interposed. Since it is an electrode plate for a liquid crystal display device in which a switching element and a pixel driving transparent electrode are formed, an electrode plate having a structure advantageous in terms of accuracy becomes simple, and a plastic substrate which can be easily manufactured is used. It becomes the electrode plate for the liquid crystal display device.

[Brief description of drawings]

FIG. 1 is a sectional view schematically showing an embodiment of an electrode plate for a liquid crystal display device according to the present invention.

FIG. 2 is a cross-sectional view schematically showing a form in which a CF and an overcoat are formed on a substrate, and a switching element and a pixel driving transparent electrode are formed thereon.

FIG. 3 is an explanatory diagram schematically showing a configuration of a plastic substrate used in a liquid crystal display device.

[Explanation of symbols]

1 ... Glass substrate 2 ... Transparent colored pattern layer (color filter (CF)) 3… Overcoat 4 ... Switching element 5 ... Pixel driving transparent electrode 6 ... Plastic substrate 7 ... Barrier layer 8 ... Transparent coating layer

Claims (2)

[Claims] 1. A transparent colored pattern layer is provided on a plastic substrate on which a barrier layer is not provided, and a switching element and a pixel driving transparent electrode are formed on the transparent colored pattern layer via a transparent coating layer. An electrode plate for a liquid crystal display device. 2. The electrode plate for a liquid crystal display device according to claim 1, wherein the transparent coating layer is an organic or inorganic electrically insulating gas blocking film and also has a function of blocking ionic impurities. .