Liquid crystal cells – elements and systems – Particular structure – Having significant detail of cell structure only
Reexamination Certificate
2000-09-05
2001-11-27
Dudek, James A. (Department: 2871)
Liquid crystal cells, elements and systems
Particular structure
Having significant detail of cell structure only
C349S155000
Reexamination Certificate
active
06323921
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to a color filter substrate and a liquid crystal display device.
PRIOR ART
Liquid crystal display devices generally used are of a structure in which liquid crystal is put or held between two glass substrates respectively having electrodes, the peripheries of the two substrates are fixed by adhesive agent in a manner except for the liquid-crystal filling hole, and the liquid crystal filling hole is hermetically sealed by sealing agent. Moreover, as spacer for allowing the distance between these two substrates to be held or kept constant, plastic beads of uniform particle diameter, etc. are scattered between the substrates.
However, in such liquid crystal display devices, at the process step for scattering spacers between two substrates, spacers are unequally disposed so that display becomes unsatisfactory, resulting in lowered yield.
In view of the above, in the color type liquid crystal display device, as shown in
FIG. 6
, colored layers R, G, B serving as color filters were respectively extended to the portions outside the pixel regions on a substrate
50
to stack these colored layers R, G, B at the portions except for the pixel regions to use the colored layers thus stacked as respective spacers to thereby eliminate the above-described problems.
However, in the liquid crystal display device of the structure in which colored layers R, G, B are stacked to thereby form spacers, there is the problem that the layer formed in such a manner that the uppermost layer of the spacer portion and the colored layer on the pixel area are continuous, e.g., the colored layer B is such that it is generally difficult to control the width dimension W of the spacer portion, and there are also instances where the width dimension W becomes great so that the spacer portion is admitted into the pixel region, resulting in reduced aperture ratio. Moreover, since the colored layer B is formed in such a manner that the uppermost layer of the spacer portion and the colored layer on the pixel region are continuous, in the case where orientation film is formed on the colored layer B, unsatisfactory orientation is apt to take place in the orientation film on a boundary region
60
. (see
FIG. 6
) between the colored layer on the pixel region and the spacer portion. For this reason, in the case where the region where such unsatisfactory orientation has taken place is admitted into the pixel region, the problem that there results unsatisfactory display takes place.
SUMMARY OF THE INVENTION
This invention has been made in consideration of the above-mentioned circumstances, and its object is to provide a color filter substrate and a color liquid crystal display device having high aperture ratio and capable of preventing unsatisfactory display as far as possible.
A color filter substrate of this invention is characterized in that it comprises: a substrate; a color filter portion composed of colored layers of plural colors disposed on the substrate; a first spacer portion constituted so that the colored layers of at least two different colors of the colored layers of the plural colors are stacked on the substrate, and one colored layer of the stacked colored layers and the colored layer of the same color as that of the one colored layer of the color filter portion are continuous with each other; and a second spacer portion constituted so that the colored layers of at least two different colors of the colored layers of the plural colors are stacked on the substrate, and all of these stacked colored layers become discontinuous with respect to any one of the colored layers constituting the color filter portion.
In other words, the first spacer portion is such that either one of colored layers of two colors constituting the spacer portion is continuous from the colored layer constituting the color filter portion, and the second spacer portion is such that both of the colored layers of two colors constituting the spacer portion are spaced from the colored layer constituting the color filter portion when viewed from the plane.
Moreover, the liquid crystal display device of this invention is characterized in that it includes the above-mentioned color filter substrate.
At the spacer portion where the uppermost layer is disposed in such a manner that it covers the stacked colored layers except for the uppermost layer, the thickness of the spacer portion changes by the mutual relationship between viscosity of colored layer material of the uppermost layer and the thickness or height of the spacer portion of the colored layers except for the uppermost layer, etc. For this reason, control of the width of the spacer portion is difficult. However, in the color filter substrate and the liquid crystal display device of this invention, there is provided the second spacer portion of the structure in which the uppermost layer of the colored layers constituting the spacer portion is discontinuous with respect to any one of the colored layers constituting the color filter portion, i.e., is spaced therefrom when viewed from the plane. For this reason, it is sufficient to control only the shape of the uppermost layer of the spacer portion. Thus, it is possible to easily control the width of the spacer portion so as to take arbitrary shape.
This invention is effective particularly in the case where there is employed the structure to dispose spacer portion such that colored layers are stacked within the pattern region of the colored layers of the color filter portion. For example, in the case where the spacer portions are formed simultaneously with formation of colored layers constituting the color filter portion and the spacer portions are disposed within the colored layer regions every respective colors of the color filter portion composed of colored layers of three colors, when the colored layer of the uppermost layer constituting the spacer portion and the colored layer of the color filter portion where that spacer portion is disposed have the same color, the uppermost layer of the spacer portion and the colored layer pattern where that spacer portion is disposed are caused to be discontinuous as in the case of the second spacer portion, whereby control of the spacer width of the uppermost layer becomes easy. Thus, it becomes possible to control the unsatisfactory orientation region resulting from the fact that the spacer portion exists within a narrow range.
Moreover, since at least one layer of the colored layers constituting the first spacer portion takes a form continuous with the colored layer constituting the color filter portion, the region where no colored layer is formed does not exist in any sense within the pattern region of the colored layers of the color filter portion, thus making it possible to prevent missing of light from the region where no colored layer is formed. Further, there is employed the structure in which the colored layer of the lower layer side of the first spacer portion is continuous from the colored layer constituting the color filter portion, whereby since the uppermost layer and the colored layer of the color filter portion are discontinuous at the first spacer portion where the colored layer of the uppermost layer constituting the spacer portion and the colored layer of the color filter portion where that spacer portion is disposed have not the same color, control of the spacer width becomes easy.
As stated above, the color filter substrate and the liquid crystal display device of this invention include the first spacer portion including colored layer continuous with the colored layer of the color filter portion and the second spacer portion including discontinuous colored layer with respect thereto to thereby form the spacer portions and the color filter portion at the same time, thus making it possible to easily control the width of the spacer portion so that the spacer portion can be disposed at an arbitrary position.
Further, another color filter substrate of this invention is characterized in that it comprises: a substrate; a color filter portion
Hatoh Hitoshi
Kurauchi Shoichi
Midorikawa Teruyuki
Miyazaki Daisuke
Dudek James A.
Finnegan Henderson Farabow Garrett & Dunner L.L.P.
Kabushiki Kaisha Toshiba
Schechter Andrew
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