JP2005084541A - Color filter structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a color filter structure that can not only effectively decrease the number of photomasks in use, but also greatly reduce the complexity and production cost of a manufacturing process. <P>SOLUTION: The color filter structure has a substrate, a light blocking layer provided in a peripheral area on a substrate surface, and a plurality of conductive filters which are provided on the substrate surface not in the peripheral area to form a common electrode. A filter is formed of a conductive material, so it can be used as a common electrode of a liquid crystal display unit. Therefore, it is not necessary to define a design pattern by forming a transparent conductive layer on a filter substrate and forming a common electrode. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a color filter structure, and more particularly, to a color filter structure of a liquid crystal display (LCD).

  A color filter of a conventional liquid crystal display is formed on both glass substrates facing each other in parallel with a thin film transistor (TFT) component as a pixel driving circuit. The thin film transistor component is formed on the surface of a lower glass substrate (also referred to as a thin film transistor substrate) by a plurality of micro etching processes. On the other hand, the color filter is formed on the upper glass substrate (also referred to as a filter substrate) by a micro process or a printing technique, so that each pixel of the liquid crystal display has a high luminance. In the manufacturing process of a liquid crystal display, a black matrix is usually formed on the filter substrate and used as a light shielding layer, thereby avoiding light beam interference between adjacent filters, improving the contrast of the LCD, and improving the light of the TFT component. In addition to preventing leakage current, it also improves problems such as oblique light leakage defects that occur during display on a liquid crystal display.

  Reference is now made to FIGS. FIG. 1 is a plan view of a conventional filter substrate, and FIG. 2 is a cross-sectional view taken along the line AA 'of the filter substrate of FIG. As shown in FIGS. 1 and 2, the filter substrate surface 10 has a predetermined area 12 and a peripheral area 14 surrounding the predetermined area 12. The planned area 12 is provided in the center of the filter substrate 10 and corresponds to the pixel area of the thin film transistor substrate. The planned area 12 includes a light shielding layer 16a formed of a black matrix and a plurality of color filters 18. These color filters are, for example, a red filter R, a green filter G, and a blue filter B, and are provided between black matrices. Thereby, when light rays pass through the filters of the respective colors, light of three primary colors such as red, green, and blue is generated, so that a color image is formed.

The peripheral area 14 is provided mainly for applying an adhesive. By such adhesive application, the filter substrate and the thin film transistor substrate of the liquid crystal display are bonded to each other. Generally speaking, the peripheral area 14 includes a light shielding layer 16b that surrounds the outside of the planned area 12, thereby preventing light rays from passing through the peripheral edge of the substrate and interfering with the image. Further, the filter substrate 10 includes a transparent conductive layer 20 that covers the surface of the filter 18, which is used as a common electrode and provides a fixed voltage (Vcom). This fixed voltage forms an appropriate voltage difference with the voltage applied to the pixel electrode of the thin film transistor substrate, and controls the gray level of each pixel.
JP 2000-089240 A JP 2001-281703 A

  When the filter substrate 10 is manufactured by the conventional method, at least four light masks are required, and the light shielding layers 16a and 16b, the red filter R, the green filter G, the blue filter B, and the like are defined. Further, a fifth photomask is required to define the pattern of the transparent conductive layer 20. Alternatively, the fabrication of the transparent conductive layer 20 and the definition of the design pattern are completed simultaneously using a shading mask. On the other hand, in order to reduce the number of optical masks used, those skilled in the art often seek other methods that can improve the utilization of a single optical mask and also define a design pattern. Alternatively, research and development is proceeding in the direction in which the transparent conductive layer is formed on the entire surface of the filter substrate (the design pattern of the transparent conductive layer need not be defined) to reduce the complexity of the manufacturing process and the production cost. For example, design patterns such as a red filter R, a green filter G, and a blue filter B are defined by sharing one light mask. As a result, the usage rate of a single optical mask can be improved and the production cost can be reduced. Certainly, by using this method, the number of light masks used can be reduced, but still utilizing the three yellow light production processes, the red filter R, the green filter G, and the blue filter It is necessary to define a design pattern such as B. After all, the effect of reducing the complexity of the manufacturing process is not significant.

  It has also been proposed to form the light shielding layers 16a and 16b using a photosensitive resin material instead of a metal material. Since the photosensitive resin material becomes a pattern pattern of the light shielding layers 16a and 16b by the exposure process and the development process, the etching process for defining the pattern pattern of the metal material can be omitted. Then, a color filter is manufactured using a photosensitive resin material, and a special design pattern in which the red filter R, the green filter G, and the blue filter B are superimposed on each other is formed by controlling the exposure intensity. Then, since the overlapping area of both filters adjacent to each other can be used as the light shielding layer, the manufacturing process can be simplified. However, whether the light shielding layer is formed using a photosensitive resin or the color filter is formed, it is necessary to precisely define the exposure position using a corresponding optical mask. It is not easy to reduce the number of optical masks that are applied.

  Therefore, how to effectively reduce the number of optical masks used and how to reduce the complexity and production cost of the manufacturing process is certainly an issue to be solved immediately in the liquid crystal display production industry. .

  Accordingly, an object of the present invention is to provide a color filter structure of a liquid crystal display so as to solve the above-described problems.

  A color filter structure according to a preferred embodiment of the present invention includes a substrate, a light shielding layer provided in a peripheral area of the substrate surface, and a plurality of conductive elements provided on the substrate surface other than the peripheral area so that a common electrode is formed. With a filter.

  Since the filter of the present invention is made of a conductive material, it can be used as a common electrode of a liquid crystal display. Therefore, in the present invention, there is no need to define a design pattern by forming a common electrode by forming a transparent conductive layer on a filter substrate. This not only effectively reduces the number of optical masks used, but also greatly reduces the complexity and production cost of the manufacturing process.

  Reference is now made to FIGS. 3 is a plan view of the filter substrate of the present invention, and FIG. 4 is a cross-sectional view taken along the line BB ′ of the filter substrate of FIG. As shown in FIGS. 3 and 4, the filter substrate surface 30 has a predetermined area 32 and a peripheral area 34 surrounding the predetermined area 32. The planned area 32 is provided in the center of the filter substrate 30 and corresponds to the pixel area of the thin film transistor substrate. The planned area 32 includes a plurality of color filters 36 formed of a conductive material. These color filters are, for example, a red filter R, a green filter G, and a blue filter B. In this way, light rays pass through these filters and generate three primary colors such as red, green and blue, so that a color image is formed. In addition, since the filters 36 in the planned area 32 are adjacent to each other or overlap each other, it is possible to form a conductive material layer continuously, and a conventional transparent conductive material such as indium tin oxide (ITO) is used. ) Can be used as a common electrode of a liquid crystal display.

  As a preferred embodiment of the present invention, it is possible to make each adjacent filter 36 have the same potential by adding the same type of conductive material to each filter 36. For example, a conductive polymer material is mixed in the filter 36 so as to have conductivity. For example, a conductive material having high transparency in the visible light region such as polyethylene dioxythiophene / polystyrene sulfate (PEDT / PSS, BAYTRON P, BAYER AG) disclosed by US Pat. No. 6,083,635 is added as an additive. It is possible. The surface impedance of the filter to which this is added is less than 300Ω / □, and the visible light transmittance for a film thickness of less than 50 μm exceeds 85%. Therefore, it is appropriate to use such a material as a common electrode of a liquid crystal display instead of a transparent conductive material such as indium tin oxide. Further, the conductive property is imparted to the filter 36 by adding another conductive additive having a small influence on the optical characteristics of the filter 36, such as metal fine particles.

  The peripheral area 34 is provided mainly for applying an adhesive. By such adhesive application, the filter substrate and the thin film transistor substrate of the liquid crystal display are bonded to each other. In addition, the peripheral area 34 includes a light shielding layer 38 that surrounds the outside of the planned area 32, thereby preventing light rays from passing through the peripheral edge of the substrate and interfering with the image. In a preferred embodiment of the present invention, the light shielding layer 38 can be made of a conductive material such as chromium metal or other alloy metal, but can also be made of an insulating material such as a photosensitive resin material. In the present invention, the design pattern of the filter 36 can be further controlled, so that the filter 36 includes a protrusion, which extends to the peripheral area 34 and covers the light shielding layer 38, Used as an internal articulating back 40. In this manner, a contact plug can be fabricated above the internal connection backing 40, and the common electrode 36 can be electrically connected to another conductive material layer.

  Reference is now made to FIG. FIG. 5 is a view showing a cross section of the filter substrate according to the second embodiment of the present invention. In the present embodiment, the peripheral area 34 includes a light shielding layer 38 b, and a light shielding layer 38 a formed of a black matrix is included in the planned area 32, and is provided between both adjacent filters 36. Thereby, the light beam interference between the adjacent filters 36 is effectively avoided. The light shielding layer 38a needs to be formed of a conductive material, and the filters 36 on both sides of each light shielding layer 38a partially cover the light shielding layer 38a. Thereby, each filter 36 in the filter substrate 30 is connected to the light shielding layer 38a to form a conductive material layer, and is used as a common electrode. The light shielding layer 38b provided in the peripheral area 34 can be formed of a conductive material or an insulating material.

  Reference is now made to FIG. FIG. 6 is a view showing a cross section of the filter substrate according to the third embodiment of the present invention. In this embodiment, the peripheral area 34 includes a light shielding layer 38 b, and a light shielding layer 38 a formed of a black matrix is included in the planned area 32, and is provided between both adjacent filters 36. Thereby, the light beam interference between the adjacent filters 36 is effectively avoided. The light shielding layer 38a is formed of an insulating material, and the filters 36 on both sides of each light shielding layer 38a are adjacent to each other and partially cover the light shielding layer 38a. Thereby, each filter 36 in the filter substrate 30 is connected to each other to form a conductive material layer, and is used as a common electrode. The light shielding layer 38b provided in the peripheral area 34 can be formed of a conductive material or an insulating material.

  Compared to a conventional color filter structure, the filter of the present invention is formed of a conductive material, and therefore can be used as a common electrode of a liquid crystal display. Therefore, in the present invention, there is no need to define a design pattern by forming a common electrode by forming a transparent conductive layer on a filter substrate. This not only effectively reduces the number of optical masks used, but also greatly reduces the complexity and production cost of the manufacturing process.

  What has been described above is only the preferred embodiments of the present invention, and equivalent changes and modifications made based on the claims of the present invention are within the scope of the patent of the present invention.

It is a top view of the filter substrate which concerns on a prior art. It is sectional drawing of the filter substrate which concerns on a prior art. It is a top view of the filter substrate of the present invention. It is sectional drawing which shows the filter substrate which concerns on the 1st Example of this invention. It is sectional drawing which shows the filter substrate which concerns on the 2nd Example of this invention. It is sectional drawing which shows the filter substrate which concerns on the 3rd Example of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Filter board | substrate 12 Scheduled area 14 Peripheral area 16a Light shielding film 16b Light shielding film 18 Filter 20 Transparent conductive layer 30 Filter substrate 32 Scheduled area 34 Peripheral area 36 Filter 38 Light shielding film 38a Light shielding film 40b Light shielding layer 40

Claims (7)

A substrate, a light shielding layer provided in a peripheral area of the substrate, and a plurality of conductive filters provided on a surface of the substrate other than the peripheral area so as to form a common electrode corresponding to the pixel area of the thin film transistor substrate. A color filter structure characterized by that. 2. The color filter structure according to claim 1, wherein the conductive filter includes at least one red filter, at least one green filter, and at least one blue filter. The color filter structure according to claim 1, wherein the conductive filter includes a conductive polymer material. The color filter structure according to claim 1, wherein the conductive filter includes conductive fine particles. A plurality of light shielding layers are included between the conductive filters, and these light shielding layers are positioned on the substrate surface other than the peripheral area of the substrate, so that light beam interference between adjacent conductive filters is avoided. 2. The color filter structure according to claim 1, wherein these light shielding layers are made of a conductive material. A plurality of light shielding layers are included between the conductive filters, and these light shielding layers are positioned on the substrate surface other than the peripheral area of the substrate, so that light beam interference between adjacent conductive filters is avoided. 2. The color filter structure according to claim 1, wherein the conductive filters are electrically connected to each other. The light shielding layer is made of an insulating material, and the conductive filter includes a protruding structure, the protruding structure extends to the peripheral area and covers the upper side of the light shielding layer, and is a back for internal connection. The color filter structure according to claim 1, wherein the color filter structure is used as a coating material.

Images