Liquid crystal cells – elements and systems – Nominal manufacturing methods or post manufacturing...
Reexamination Certificate
2002-01-14
2004-02-10
Chowdhury, Tarifur R. (Department: 2871)
Liquid crystal cells, elements and systems
Nominal manufacturing methods or post manufacturing...
C349S189000, C349S106000, C349S156000, C349S113000
Reexamination Certificate
active
06690448
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of Invention
The present invention relates to transflective liquid crystal devices by which a reflective display that uses light reflected after passing through a liquid crystal layer and a transmissive display that uses light transmitted through the liquid crystal layer can be manufactured, and in which a color filter can be disposed on a light path so that color display can be realized.
2. Description of Related Art
Recently, liquid crystal devices have come into widespread use in electronic devices, such as mobile phones, portable computers, etc. In such liquid crystal devices, reflective liquid crystal devices, in which a light reflecting film is provided on an inside or outside surface of a substrate disposed at the side opposite to the observer's side of a liquid crystal layer, are known in the art. In reflective liquid crystal devices, light incident from the observer's side is reflected at the light reflecting film, and is used as a light source for display.
In addition, transmissive liquid crystal devices, in which an illuminating device, that is, a so-called backlight, is disposed at the side opposite to the observer's side of a liquid crystal layer and is used as a light source for display, are also know in the art. In addition, transflective liquid crystal devices, in which openings are formed in a light reflecting film, and in which reflective display is realized using regions excluding the openings in the light reflecting film and transmissive display is realized using the light passing the openings in the light reflecting film, are also known in the art.
On the other hand, recently, color display is often realized in liquid crystal devices by disposing a color filter having R (red), G(green), and B(blue) or C(cyan), M(magenta), and Y(yellow) subpixels, in a display area of the liquid crystal devices.
SUMMARY OF THE INVENTION
According to a known technique of color transflective displays, in which openings are formed in a light reflecting film and a color filter is used, uniform color display over the display area cannot be realized. The inventors have performed various experiments to discover the reason for this, and found that color display cannot be made uniform if the relationship between the openings in the light reflecting film and the R, G, and B or C, M, and Y subpixels regarding position and shape are not adequately coordinated.
In view of the above-described finding, an object of the present invention is to provide a transflective liquid crystal device in which color display can be made uniform over the display surface in both the reflective display mode and the transmissive display mode.
In order to attain the above-described object, according to a first aspect of the present invention, a liquid crystal device can include a pair of substrates which sandwich liquid crystal, a light reflecting film formed on at least one of the substrates, and a color filter formed on the light reflecting film. The color filter can include a partitioning member, which divides the surface of the substrate into a plurality of sections, and subpixels, which are individually formed in the sections, and openings are formed in the light reflecting film at regions corresponding to thickest parts of the subpixels.
The partitioning member may be formed by, for example, applying an ink-repellent resin at a uniform thickness by a known deposition method, for example, spin coating, and forming a predetermined pattern by a known patterning method, for example, photolithography. In addition, the above-described subpixels are formed by, for example, an inkjet method, that is, by ejecting, in the form of drops, a subpixel material from nozzles of an inkjet head toward the sections devided by the partitioning member.
In the liquid crystal device according to the first aspect of the present invention, as shown in
FIG. 5
, openings
18
are formed in a light reflecting film
9
at regions corresponding to thickest parts of subpixels
16
. Thus, in the reflective display mode, light that passes through the subpixels
16
to and from the light reflecting film
9
at parts excluding the thickest parts of the subpixels
16
, as shown by the arrow X
0
, is used for color display. In addition, in the transmissive display mode, light that passes through the subpixels
16
at thickest parts thereof, as shown by the arrow X
1
, is used for color display.
Accordingly, light that is transmitted through the subpixels
16
once at the thickest parts thereof is used in the transmissive display mode, and light that is transmitted through the subpixels
16
twice at relatively thin parts thereof is used in the reflective display mode. Accordingly, the optical thickness in the reflective display mode and that in the transmissive display mode can be made close or approximately the same, so that color display can be made uniform between the reflective display mode and the transmissive display mode.
According to a second aspect of the present invention, a liquid crystal device can include a pair of substrates which sandwich liquid crystal, a light reflecting film formed on at least one of the substrates, and a color filter formed on the light reflecting film. The color filter can include a partitioning member, which divides the surface of the substrate into a plurality of sections, and subpixels, which are individually formed in the sections, and openings are formed in the light reflecting film at regions corresponding to central parts of the sections.
The partitioning member may be formed by, for example, applying an ink-repellent resin at a uniform thickness by a known deposition method, for example, spin coating, and forming a predetermined pattern by a known patterning method, for example, photolithography. In addition, the above-described subpixels are formed by, for example, the inkjet method, that is, by ejecting, in the form of drops, a subpixel material from nozzles of an inkjet head toward the sections.
As shown in FIG.
5
(
a
) and FIG.
5
(
c
), in the case in which the subpixels
16
are formed by the inkjet method, the subpixels
16
tend to swell upward at central regions of the sections divided by a partitioning member
14
. Accordingly, when the openings
18
are formed in the light reflecting film
9
at regions corresponding to the central parts of the sections divided by the partitioning member
14
, the optical thickness in the reflective display mode and that in the transmissive display mode can be made close or approximately the same. Thus, color display can be made uniform between the reflective display mode and the transmissive display mode.
According to a third aspect of the present invention, a liquid crystal device can include a pair of substrates which sandwich liquid crystal, a light reflecting film formed on at least one of the substrates, and a color filter formed on the light reflecting film. The color filter can include a partitioning member, which divides the surface of the substrate into a plurality of rectangular sections, and subpixels, which are individually formed in the rectangular section, and openings are formed in the light reflecting film in such a manner that the openings extend in the longitudinal direction of the rectangular sections.
The partitioning member may be formed by, for example, applying an ink-repellent resin at a uniform thickness by a known deposition method, for example, spin coating, and forming a predetermined pattern by a known patterning method, for example, photolithography. In addition, the above-described subpixels are formed by, for example, the inkjet method, that is, by ejecting, in the form of drops, a subpixel material from nozzles of an inkjet head toward the sections.
Generally, in order to realize color display, especially full-color display, a unit including R, G, and B subpixels functions as a pixel, and a full-color image is displayed by controlling the color illuminated in each pixel. The R, G, and B subpixels are often formed in a rectangular shape. In such a case, as shown i
Aruga Hisashi
Ito Tatsuya
Katagami Satoru
Kawase Tomomi
Chowdhury Tarifur R.
Seiko Epson Corporation
LandOfFree
Liquid crystal device, liquid crystal device manufacturing... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Liquid crystal device, liquid crystal device manufacturing..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Liquid crystal device, liquid crystal device manufacturing... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3345534