Liquid crystal cells – elements and systems – Nominal manufacturing methods or post manufacturing... – Injecting liquid crystal
Reexamination Certificate
1998-10-13
2001-08-07
Parker, Kenneth (Department: 2871)
Liquid crystal cells, elements and systems
Nominal manufacturing methods or post manufacturing...
Injecting liquid crystal
C349S076000, C349S153000, C349S190000
Reexamination Certificate
active
06271907
ABSTRACT:
FIELD OF THE INVENTION AND RELATED ART
The present invention relates to a color liquid crystal device for use in a display apparatus etc.
With an increasing size of display images, a liquid crystal display apparatus capable of lightening an apparatus weight has attracted notice. In recent years, there has been extensively studied principally a TV image displaying method by using an active matrix-type liquid crystal device wherein a nematic liquid crystal is directly driven by providing each pixel with a switching element. Further, there has been required a high density (resolution) display (of XGA (extended graphics array)-mode or SXGA (super extended graphics array)-mode) represented by, e.g., a display monitor for a personal computer.
On the other hand, a liquid crystal device of the type which controls transmission of light in combination with a polarizing device by utilizing a refractive index anisotropy of chiral smectic (ferroelectric) liquid crystal molecules, has been proposed by Clark and Lagerwall (Japanese Laid-Open Patent Application (JP-A) 56-107216, U.S. Pat. No. 4,367,924). The chiral smectic liquid crystal generally has chiral smectic C phase (SmC*) or H phase (SmH*) in a specific temperature range and, in the phase, shows a property of assuming either one of a first optically stable state and a second optically stable state in response to an electric field applied thereto and maintaining such a state in the absence of an electric field, namely bistability, and also have a very quick response speed. Accordingly, the chiral smectic liquid crystal is expected to be applied to a display device of a high speed and a memory-type, particularly a display device of a high resolution and a large picture area driven by a simple matrix-driving scheme, thus allowing a higher duty ratio of at most 1/3000 which is impossible for the nematic liquid crystal.
FIG. 14A
is a schematic plan view of a conventional liquid crystal device driven by a simple matrix-driving scheme, and
FIG. 14B
is a schematic sectional view thereof.
Referring to the figures, the liquid crystal device include a substrate
1
provided with a group of scanning electrodes formed in a stripe shape (not shown) (herein, such a substrate
1
is referred to as “scanning-side substrate”). The group of scanning electrodes are electrically connected to driver ICs (integrated circuits) as external drive circuits (not shown) each provided with a TAB (tape automated bonding) film
3
. The liquid crystal device also includes a substrate
2
provided with a group of data electrodes formed in a stripe shape (not shown) (herein, such a substrate
4
is referred to as “data-side substrate”). The group of data electrodes intersect the group of scanning electrodes at right angles and are electrically connected to driver ICs as external drive circuits (not shown) each provided with a TAB film
3
at mutually opposite sides (in which the data electrodes are divided) of the data-side substrate
4
in an extension (longitudinal) direction of the data electrodes.
The (scanning-side and data-side) substrates
1
and
4
are applied to each other at the periphery thereof via a sealing agent
7
formed in a prescribed pattern so as to leave a liquid crystal injection port
8
which is sealed up with a injection port sealing material
9
after a liquid crystal injection.
In the conventional simple matrix-type liquid crystal device, a smaller number of the scanning electrodes are electrically connected to the external drive circuits at one of mutually opposite sides of the scanning-side substrate in the extension direction of the scanning electrodes. On the other hand, the data electrodes on the data-side substrate are electrically connected to the external drive circuits at the opposite sides (in the data electrode extension direction) between which the data electrodes are alternately apportioned for electrical connection.
In such a conventional liquid crystal device, the liquid crystal injection port has been provided at a side opposite to the side where the scanning electrodes are electrically connected with the external drive circuits, i.e., a side free from electrical connection with the external drive circuits.
However, when a (ultra-) higher resolution color display of a level of 300 dpi (300 pixels per 1 inch) is required, a larger picture area (e.g., of 15 in.-size) includes a large number of scanning and data electrodes each for exceeding 5000 lines. In this instance, in view of a connection pitch with the external drive circuits at the opposite two sides (in the electrode extension direction) for both the scanning-side substrate and the data-side substrate. When the external drive circuits are electrically connected with corresponding scanning electrodes or data electrodes, the substrate to be subjected to external electrical connection is required to be disposed so as to be protruded (outward) from the other substrate end (edge) as shown in FIG.
1
.
Referring to
FIG. 1
, (stripe) scanning electrodes
2
and (stripe) data electrodes
5
are required to be extended to corresponding side portions in electrode extension directions, respectively, in order to effect electrical connection with corresponding external drive circuits (TAB films
3
and
6
).
For each substrate
1
(or
4
), at other opposite two sides, the scanning electrodes
2
(or the data electrodes
5
) are not required to be formed in the vicinity of the sides because of no electrical connection with the external drive circuits.
In the case where the above-mentioned electrical connection structure (as shown in
FIG. 1
) is employed in a color liquid crystal device including a color filter
32
disposed on a substrate
30
and a flattening film
33
(e.g., of a resin) covering the color filter
32
and stripe electrodes
34
(e.g., of ITO (indium tin oxide) film) formed on the flattening film
33
as shown in
FIG. 3
, at the sides where the stripe electrodes
34
are electrically connected with external drive circuits, the color filter
32
and the flattening film
33
are also extended to the electrically connected side portions.
In such a case, a liquid crystal injection port
8
is also located in the vicinity of one of four electrically connected side portions of a rectangular (color) liquid crystal device as shown in FIG.
1
. After the liquid crystal injection is completed, when an excessive liquid crystal portion attached to an inner surface of a (protruded) substrate (the substrate
1
in
FIG. 1
) is wiped up with a cotton swab impregnated with a wiping solvent for the liquid crystal, the flattening film
33
(as shown in
FIG. 3
) is removed from the substrate
30
if the substrate
1
(
FIG. 1
) is provided with the color filter
32
and the flattening film
33
as in the substrate
30
(FIG.
3
). As a result a part of the scanning electrodes
2
(
FIG. 1
) is also removed from the substrate
1
, thus causing electrical connection failure (electrode breakage).
SUMMARY OF THE INVENTION
An object of the present invention is to provide a color liquid crystal device of a high reliability, a high resolution (definition) and a large picture area and free from a problem of electrode breakage while keeping a mass-productive liquid crystal injection scheme with respect to a rectangular cell structure to be electrically connected with external drive circuits at all the four sides thereof.
Another object of the present invention is to provide a process for producing the color liquid crystal device.
According to the present invention, there is provided a color liquid crystal device, comprising: a pair of rectangular substrates disposed opposite to each other to form a cell structure having a liquid crystal injection port, and a liquid crystal injected into the cell structure through the liquid crystal injection port, the pair of rectangular substrates including a first substrate provided with a color filter and stripe electrodes disposed on the color filter and a second substrate provided with stripe electrodes disposed opposite to and intersecting the s
Masaki Yuichi
Suzuki Masa-aki
Canon Kabushiki Kaisha
Fitzpatrick ,Cella, Harper & Scinto
Parker Kenneth
Qi Mike
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