JPH0641213Y2 - Color liquid crystal display element - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a color liquid crystal display device of the present invention.

[Conventional technology]

As is well known, a matrix-type liquid crystal display element for displaying a television image or the like has a large number of stripe-shaped transparent signal electrodes arranged in parallel on one of a pair of transparent substrates facing each other with a liquid crystal layer in between, On the other substrate, a large number of stripe-shaped transparent scanning electrodes that intersect and intersect the scanning electrodes are arranged in parallel, and a color liquid crystal display element that displays a full-color image is red on each electrode of one of the substrates.
The configuration is such that green and blue stripe color filters are alternately provided.

As this color liquid crystal display element, it is generally known that red, green, and blue color filters are provided on the electrodes (on the liquid crystal layer side). In this way, the color filters are provided on the electrodes. The existing color liquid crystal display device has a problem that the voltage applied to the liquid crystal layer is lowered due to the voltage drop in the color filter and the contrast of the displayed image is deteriorated.

For this reason, recently, it has been considered to form electrodes on the red, green, and blue color filters. If the electrodes are provided on the color filters in this way, the voltage is applied between the electrodes of both substrates. Since a voltage can be applied to the liquid crystal layer without causing a voltage drop in the color filter, a full-color image with good contrast can be displayed.

FIG. 3 shows a cross section of a conventional color liquid crystal display device having electrodes provided on a color filter, taken along the length direction of the scanning electrodes. The color liquid crystal display device has the following structure. In the figure, reference numerals 1 and 2 denote a pair of upper and lower transparent substrates (glass plates) facing each other across the liquid crystal layer LC. A large number of transparent signal electrodes 3 each having a stripe shape are arranged in parallel. On the inner surface of the lower substrate 2 (the surface facing the upper substrate 1), a plurality of stripe-shaped transparent scanning electrodes 4 which intersect and oppose the signal electrodes 3 are arrayed in parallel, and each scanning electrode 4 is formed. Are provided on the striped color filters FR, FG, FB formed on the lower substrate 2 surface so as to face the respective signal electrodes 3 on the upper substrate 1 surface. FR is a red filter, FG is a green filter, and FB is a blue filter.The color filters FR, FG, and
The FBs are arranged in an alternating manner as shown in the figure. In each of the color filters FR, FG, FB, a filter base film made of a photosensitive resin is formed on the surface of the lower substrate 2 and the filter base film is patterned into stripes by exposure and development processing, and then the filter base film is dyed. The color filters FR, FG, FB for each color
Are formed in the order of, for example, the red filter FR, the green filter FG, and the blue filter FB, and the side edges of the adjacent color filters are wrapped as shown. The surface of each of the color filters FR, FG, FB is transparently covered with a protective film 5, and the scanning electrodes 4 are formed on the protective film 5.
The end portion of the scanning electrode 4 is led to the surface of the substrate 2 and led to the side edge portion of the substrate as a drive circuit connecting terminal 4a. Also,
Reference numeral 6 denotes a thin stripe light-shielding film made of chrome or the like formed on the surface of the lower substrate 2 so as to face the gap between the signal electrodes 3 on the surface of the upper substrate 1. This light-shielding film 6 is used for each signal electrode 3
The color filters FR, FG, and FB are provided in order to prevent light from leaking from the gap between them, and the filter side edges are formed on the light-shielding film 6. In addition, 7a, 7b
Is an alignment treatment film provided on the electrode formation surface of both substrates 1 and 2, 8
Is a sealing material, and 9a and 9b are polarizing plates.

[Problems to be solved by the invention]

However, since the above-mentioned conventional color liquid crystal display element has the scanning electrode 4 provided on the color filters FR, FG, FB, it is applied between the signal electrode 3 and the scanning electrode 4 on both substrates 1 and 2. Although a voltage can be applied to the liquid crystal layer without causing a voltage drop, in this color liquid crystal display element, the side edge portions of the color filters FR, FG, FB overlap the light shielding film 6, and Since the side edges of the adjacent color filters overlap each other on the light-shielding film 6, the wrap portion of the color filter rises considerably, and therefore the scanning electrode formed on the color filter through the protective film 5 is formed. 4 becomes extremely thin at the portion along the rising surface of the raised portion where the color filter is wrapped, and this portion of the scanning electrode 4 has a large electric resistance or is disconnected. I had a problem that That is, the scan electrode 4 has the color filters FR, FG, FB and the protective film 5 formed on the surface of the substrate 2, and
A transparent conductive film made of a transparent conductive material such as ITO is formed on the entire surface of the substrate 2 by a sputtering method and the transparent conductive film is patterned. When forming the scanning electrode 4, the transparent conductive film is formed on the substrate surface. When depositing a conductive material, the transparent conductive material cannot be deposited sufficiently on the rising surface of the raised portion, so that the thickness of the transparent conductive film at this portion cannot be made sufficiently thick. This part of 4 will become extremely thin and will have a large electric resistance or will be disconnected.

The present invention has been made in view of the above situation, and the purpose thereof is to provide an electrode on the color filter while increasing the contrast by providing the electrode on the color filter. It is an object of the present invention to provide a color liquid crystal display element capable of preventing an increase in electric resistance of this electrode and a disconnection by forming the electrode with a sufficient thickness over its entire length.

[Means for solving problems]

In order to achieve the above-mentioned object, the present invention applies a high-viscosity organic substance having a viscosity of 150 to 200 cps in a liquid state on a color filter formed on a substrate, flattens it with the fluidity of the liquid high-viscosity organic substance, and then bake To form a transparent protective film comprising an upper layer film formed by applying an organic substance having a viscosity lower than that of the high-viscosity organic substance on the lower layer film and then baking the lower layer film. The transparent electrode is formed on the top.

[Action]

That is, in the color liquid crystal display device of the present invention, the protective film formed on the color filter is a two-layer film as described above. And
Since the high-viscosity organic substance having a viscosity of 150 to 200 cps, which is the lower layer film of the protective film, is difficult to flow, when this high-viscosity organic substance is applied to the uneven coated surface, the organic substance remains thick in the low portion of the coated surface. The lower layer film formed by applying the high-viscosity organic substance has a surface irregularity that is considerably smaller than that of the coating surface. Therefore, the protective film formed by applying an organic substance having a lower viscosity than the high-viscosity organic substance as the upper layer film on the lower layer film has a substantially flat film surface, and thus is transparent on the protective film. When forming the electrodes, the transparent conductive material can be applied over the entire protective film in a substantially uniform and sufficient thickness. Therefore, according to the present invention, the electrodes on the color filter can be provided with a sufficient thickness over the entire length. It is possible to prevent the increase of the electric resistance of this electrode and the breakage of the wire.

〔Example〕

 An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows a cross section along the length direction of the scanning electrodes of the color liquid crystal display element. In FIG. 1, the same components as those of the conventional color liquid crystal display element shown in FIG. 3 are designated by the same reference numerals and the description thereof will be omitted. In FIG.
FR, FG, and FB are red, green, and blue striped color filters that are alternately arranged on the lower substrate 2 side. These color filters FR, FG, FB are formed so as to face the stripe-shaped signal electrodes 3 on the surface of the upper substrate 1, and the color filters FR, FG, FB have a gap between them. Is formed. 10 is the above color filter
A transparent protective film formed on the front surface of the lower substrate 2 on the FR, FG, and FB. The protective film 10 includes a lower layer film 11 formed by applying an organic substance having a high viscosity, and the lower layer film 11. It is a two-layer film including an upper layer film 12 formed by applying an organic substance having a low viscosity thereon. And the lower layer film of this protective film 10
11 is the lower part of the coated surface, that is, each color filter F
The gap between R, FG, and FB and the substrate surface outside the color filter formation area are thick, and the high portion of the coating surface, that is, the portion on the color filters FR, FG, and FB are thin, and each color filter FR, The thickness of the lower layer film 11 on the side edges of the FG and FB, that is, on the raised portion that overlaps the light-shielding film 6, is smaller than the thickness on the central portion of the color filter. That is, the lower layer film 11 is a film in which the unevenness of the surface is considerably smaller than the unevenness of the coating surface, and therefore, the surface of the protective film 12 (upper layer having the upper film 12 formed on the lower layer film 11 The surface of the film 12) is a substantially flat surface with almost no unevenness.

The stripe-shaped scanning electrodes 4 formed on the lower substrate 2 side so as to cross each signal electrode 3 on the surface of the upper substrate 1 are formed on the protective film 10, and on the scanning electrodes 4. Is an alignment treatment film over the entire area surrounded by the sealing material 8.
7b is formed.

FIG. 2 shows a method for manufacturing the lower substrate 2, and the lower substrate 2 is manufactured as follows. First, as shown in FIG. 2A, a light-shielding film 6 in the form of narrow stripes is formed on the surface of the substrate 2. The light-shielding film 6 is formed by depositing a metal such as amorphous silicon or chrome on the surface of the substrate 2 by sputtering to a thickness of 1000 to 3000 Å, and patterning it by photoetching. Second
As shown in FIG. 2B, a color filter is formed on the substrate 2.
FR, FG, FB are formed sequentially. In this color filter, a filter base film made of a photosensitive resin is applied to almost the entire surface of the substrate 2 and the filter base film is exposed through an exposure mask. After patterning the base film in a stripe shape with a predetermined width, after baking the patterned filter base film, it is dyed in any one of red, green and blue colors,
It is formed by a method of applying a stain-proof treatment.

After that, a high-viscosity organic substance (polymer material such as polyimide) having a viscosity of 150 to 200 cps is applied to the entire surface of the substrate 2 by a spin coating method, and is baked at 160 to 200 ° C., as shown in FIG. 2 (c). As shown, the lower layer film 11 of the protective film 10 is formed. Since the lower layer film 11 is formed by applying a high-viscosity organic substance, the surface of the lower layer film 11 is a flat surface with little unevenness. This is because the high-viscosity organic substance that forms the lower layer film 11 is difficult to flow.When this high-viscosity organic substance is applied to the uneven coated surface, the high-viscosity organic substance remains thick in the low portion of the coated surface. The unevenness on the surface of the lower layer film 11 formed by applying the organic substance is considerably smaller than the unevenness on the applied surface. Next, a low-viscosity organic substance (polymer material such as polyimide) having a viscosity of 10 to 30 cps is applied over the entire surface of the lower layer film 11 by a spin coating method, and is baked at 160 to 200 ° C. A lower layer film 12 of the protective film 10 is formed as shown in FIG. This upper layer film 12 is
It is formed in order to make the surface of the protective film 10 closer to a flat surface and to smooth the surface of the protective film 10, and the protective film completed by forming the upper layer film 12 on the lower layer film 11.
10 is a film having a substantially flat film surface with almost no unevenness.

After that, the electrode 4 may be formed on the protective film 5 by scanning, and then the alignment treatment film 7b may be formed thereon. The scanning electrode 4 is formed by forming a transparent conductive film made of a transparent conductive material such as ITO on the entire surface of the protective film 5 by a sputtering method or the like and patterning the transparent conductive film.

Therefore, in the color liquid crystal display element, the protective film 10 formed on the color filters FR, FG, and FB is a two-layer film as described above, so that the surface of the protective film 10, that is, the electrode forming surface is uneven. Since there is almost no flat surface, the transparent conductive material can be deposited to a substantially uniform and sufficient thickness over the entire protective film when forming the electrode 4 on the protective film 10. Therefore, according to this color liquid crystal display element, the electrodes are provided on the color filters to increase the contrast, but the electrodes 4 on the color filters FR, FG, FB are made to have a sufficient thickness over their entire length. By forming it, it is possible to prevent an increase in the electric resistance of the electrode 4 and a disconnection.

In the above embodiment, the color filters FR, FG, FB are formed with a gap between them, but the color filters FR, FG, FB are the conventional color liquid crystal shown in FIG. It may be formed by wrapping the side edges together like a display element, and even in that case, if the protective film on the color filter is a two-layer film as described above, the surface of the protective film is made substantially flat. , The electrode can be formed on it over its entire length to a sufficient thickness. Further, although the color filters FR, FG, and FB are formed in the stripe shape in the above-described embodiment, the color filter may be formed in a dot shape, and the color filter and the protective film 10 are formed on the signal electrode 3 on the upper substrate 1 side. It may be formed below.

[Effect of device]

According to the color liquid crystal display device of the present invention, the electrodes are provided on the color filter to increase the contrast, but the electrode on the color filter is formed to have a sufficient thickness over its entire length. It is possible to prevent an increase in electric resistance and disconnection.

[Brief description of drawings]

1 and 2 show an embodiment of the present invention. FIG. 1 is a sectional view taken along the length direction of the scanning electrodes of a color liquid crystal display device, and FIG. 2 is a lower substrate on which a color filter is formed. FIG. FIG. 3 is a cross-sectional view of a conventional color liquid crystal display element taken along the length direction of the scanning electrodes. 1 ... upper substrate, 2 ... lower substrate, 3 ... scanning electrode, 4 ...
Signal electrode, FR ... Red filter, FG ... Green filter,
FB: Blue filter, 6 ... Shading film, 7a, 7b ... Alignment treatment film, LC ... Liquid crystal layer, 9a, 9b ... Polarizing plate, 10 ... Protective film, 11 ... Underlayer film, 12 ... Upper membrane.

Claims (1)

[Scope of utility model registration request] 1. A plurality of transparent electrodes are formed on one of a pair of transparent substrates facing each other across a liquid crystal layer, and a color filter is formed on the other substrate so as to face each electrode of the one substrate. In a color liquid crystal display device in which a plurality of transparent electrodes facing each electrode of the one substrate are formed in parallel on the color filter, a high viscosity of 150 to 200 cps is provided on the color filter formed on the other substrate. A lower layer film formed by applying a viscous organic substance in a liquid state, flattening the fluidity of the liquid high viscous organic substance by fluidity, and then firing, and applying an organic substance having a lower viscosity than the high viscosity organic substance on the lower layer film. A color liquid crystal display device, comprising: forming a transparent protective film including an upper layer film formed by post-baking, and forming the transparent electrode on the protective film.