Radiation imagery chemistry: process – composition – or product th – Radiation modifying product or process of making – Screen other than for cathode-ray tube
Reexamination Certificate
1999-09-03
2001-05-15
McPherson, John A. (Department: 1756)
Radiation imagery chemistry: process, composition, or product th
Radiation modifying product or process of making
Screen other than for cathode-ray tube
C349S106000, C347S107000
Reexamination Certificate
active
06232022
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a method for manufacturing a color filter applicable to a color liquid-crystal display used for a color television, a personal computer, a car navigation system, a small-size television or the like, and to a liquid-crystal device using a color filter manufactured by the method.
2. Description of the Related Art
Recently, in accordance with development of personal computers, particularly, portable personal computers, there is an increasing demand for liquid-crystal displays, particularly, color liquid-crystal displays. However, in order to realize further diffusion of such displays, it is necessary to reduce the production cost of the displays. Particularly, there is an increasing request for cost reduction of color filters whose cost occupies a considerable part of the cost of the displays.
Various approaches have been tried in order to respond to the above-described request while satisfying characteristics required for color filters. The first task in color-filter manufacturing methods is to uiformly color each pixel (a colored portion) of a color filter. Namely, it is necessary to make the amount of a coloring material per unit area for each pixel uniform.
Conventionally, in a pigment dispersion method which is widely used as a color-filter manufacturing method, the amount of a coloring material per unit area of a colored portion is made uniform by making the thickness of a film forming the colored portion constant. Recently, color-filter manufacturing methods according to an ink-jet method have been proposed, and various proposals for making the degree of coloring for each pixel uniform have been provided, for example, in Japanese Patent Laid-Open Application (Kokai) No. 9-281324 (1997), and the like. More specifically, the amount of discharged ink from each nozzle is obtained by discharging in advance ink from nozzles of an ink-jet head onto a medium, and the amount of supplied ink per unit area in the entire colored portion of a color filter is made constant based on the obtained result.
The assignee of the present application has proposed a method for making an optical effect of each pixel uniform. This method intends to reduce unevenness in color which is considered occur due, for example, to a difference in the distribution of coloring within a pixel depending on a position within a colored region. The optical effect indicates the density of coloring of a pixel. More specifically, the optical density is a physical amount related to the density of coloring. It is considered to be rational to use the radiant flux of light passing through each pixel when projecting light in the same condition as in the actual state of use of the concerned color filter as this physical amount. Actually, although illumination for a color filter is not entirely identical for each pixel, the illumination may, in many cases, be dealt with as substantially identical. In such cases, the radiant flux of light passing through each pixel for a constant amount of incident light is used as the above-described physical amount.
However, when measuring the radiant flux of light passing through each pixel in order to make the optical effect uniform, if the area of an aperture of a black matrix differs, the radiant flux of light passing through a pixel differs and therefore the optical effect differs even for the same density of coloring. Accordingly, even if coloring conditions are corrected so as to provide a uniform optical effect in the measured color filter, the optical effect differs when the area of an aperture of a black matrix differs in a color filter to be newly colored.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a method for manufacturing a color filter which does not have unevenness in color by exactly correcting coloring conditions in consideration of influence of the distribution of the areas of respective apertures of a black matrix.
It is another object of the present invention to provide a liquid-crystal device using a color filter manufactured by the above-described manufacturing method.
According to one aspect of the present invention, a method for manufacturing a color filter including a black matrix having apertures on a substrate, and pixels obtained by coloring the aperatures includes the step of correcting coloring conditions for the color filter based on a distribution of areas of the respective apertures.
In the present invention, by taking into consideration of the distribution of the areas of respective apertures of a black matrix for the optical effect of each pixel of a color filter, it is possible to improve unevenness in color due to the distribution of the areas of the respective aperatures of the black matrix.
In the present invention, by estimating the areas of respective apertures of a black matrix of a color filter, means for or a step of measuring the areas of the respective apertures of the black matrix becomes unnecessary, and therefore a manufacturing process can be simplified.
Particularly, when the filter is manufactured by dividing a region to be colored into a plurality of scanning regions, and each of the scanning regions is colored with the same conditions, the difference between measured values of the optical effect of pixels having the same coloring conditions reflects the difference between the areas of respective apertures. Hence, the area of an aperture can be estimated by comparing the measured values. It is also possible to determine the area of the aperture of a pixel positioned between these pixels by linear interpolation using the measured values. When coloring a region by dividing it into a plurality of scanning regions, unevenness in color tends to appear at the border between adjacent scanning regions. According to the present invention, however, such unevenness in color can be improved.
According to another aspect of the present invention, a liquid-crystal device includes a color filter manufactured by the above-described method, a facing substrate facing the color filter, and a liquid crystal sealed between the color filter and the facing substrate.
The foregoing and other objects, advantages and features of the present invention will become more apparent from the following description of the present invention taken in conjunction with the accompanying drawings.
REFERENCES:
patent: 5670205 (1997-09-01), Miyazaki et al.
patent: 5726724 (1998-03-01), Shirota et al.
patent: 8-292310 (1996-11-01), None
patent: 9-281324 (1997-10-01), None
Fujiike Hiroshi
Hayashi Satoshi
Marumoto Yoshitomo
Canon Kabushiki Kaisha
Fitzpatrick ,Cella, Harper & Scinto
McPherson John A.
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