Liquid crystal cells – elements and systems – Particular structure – Having significant detail of cell structure only
Reexamination Certificate
2001-11-02
2003-11-25
Ngo, Julie (Department: 2871)
Liquid crystal cells, elements and systems
Particular structure
Having significant detail of cell structure only
C349S106000, C349S149000, C430S007000
Reexamination Certificate
active
06654084
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a liquid crystal display device having liquid crystal sealed in a space secured between an array substrate and a filter substrate.
BACKGROUND ART
As
FIGS. 7 and 8
show, a conventional liquid crystal display device
101
is provided with an array substrate
103
having display elements
102
(each composed of, for example, a thin-film transistor and a pixel electrode connected thereto) formed in a matrix-like array and a filter substrate
106
having an opposing electrode
105
(a transparent electrode made of ITO or the like) formed thereon with a color filter
104
and an insulating layer OC sandwiched in between. The opposing electrode
105
is, all around or at part of the periphery thereof, so formed as to cross and reach beyond a sealing member
107
provided between the two substrates
103
and
106
, thereby forming a lead portion. Through this lead portion, the two substrates
103
and
106
are electrically connected together by a connecting member
109
outside the sealing member
107
. The region enclosed by the sealing member
107
is filled with liquid crystal
108
.
However, in this structure, where the opposing electrode
105
crosses the bonding surface of the sealing member
107
as described above, the sealing member
107
is kept in intimate contact with the opposing electrode
105
. As a result, under the negative pressure applied when the liquid crystal
108
is injected, the adhesion between the filter substrate
106
and the sealing member
107
is insufficient, degrading the hermeticity of the liquid crystal display device
101
. The factor that degrades the hermeticity between the filter substrate
106
and the sealing member
107
is either insufficient adhesion between the opposing electrode
105
and the sealing member
107
or insufficient adhesion between the opposing electrode
105
and the insulating layer OC laid thereunder. In particular, as multiple layer structure becomes increasingly common in that portion of the filter substrate
106
which serves as the base layer to which the sealing member
107
is bonded, the base layer portion tends to exhibit poorer adhesion. An object of the present invention is to increase adhesion between a sealing member and a filter substrate.
On the other hand, the color filter
104
provided on the filter substrate
106
are composed of color elements (R, G, and B) arranged in a known arrangement, such as a stripe arrangement, mosaic arrangement, or delta (triangular) arrangement. Whereas low-resolution products adopt a mosaic or delta arrangement, high-resolution products adopt a stripe arrangement.
FIG. 9
is a sectional view of the conventional liquid crystal display device
101
, taken along the direction in which the stripes of the color filter
104
are arranged. As this figure shows, on a transparent substrate
110
(made of glass or the like) of the array substrate
103
are formed gate conductors
112
for scanning and source conductors (not shown) for signal transfer, and within the regions demarcated by those conductors are formed display elements
102
each composed of a thin-film transistor (not shown) and a pixel electrode
111
(a transparent electrode made of ITO or the like) connected thereto. The greater parts of the individual pixel electrodes
111
are located within the demarcated regions mentioned above, and are laid on a layer insulation film
116
composed of a single layer or multiple layers. The remaining parts of the individual pixel electrodes
111
, however, are located out of the demarcated regions mentioned above, and are laid over the gate conductors
112
with the gate insulation film
116
sandwiched in between.
On a transparent substrate
114
(made of glass or the like) of the filter substrate
106
are formed the color filter
104
provided with R, G, and B color elements, light-shielding patches constituting a black matrix
104
K, and the opposing electrode
105
covering all these. The color filter
104
, adopting a stripe arrangement, have their constituent color elements arranged so as to form stripes of different colors; that is, color elements of an identical color are arranged along each of the source conductors for signal transfer on the black matrix
104
K. As the figure shows, the color filter
104
, having a stripe arrangement, is formed continuously so as to cover the black matrix
104
K.
However, in this structure, where the color filter
104
covers the black matrix
104
K completely as described above, on the surface of the color filter
104
are formed elevated portions C that project toward the gate conductors
112
and the source conductors. This makes it difficult to stably hold spacers (not shown) for securing cell gaps on the gate conductors
112
and the source conductors. Moreover, the presence of the elevated portions C shortens the distances from the opposing electrode
105
to the gate conductors
112
and the source conductors, and thereby contributes to the emergence of parasitic capacitance. Another object of the present invention is to stabilize cell gaps. Still another object of the present invention is to reduce the parasitic capacitance appearing between an opposing electrode and gate and source conductors.
DISCLOSURE OF THE INVENTION
To achieve the above objects, according to the present invention, a liquid crystal display device is provided with: an array substrate having display elements formed in a matrix-like array; a filter substrate having a color filter and an opposing electrode formed thereon; a sealing member laid in the shape of a loop between the array and filter substrates in peripheral portions thereof, liquid crystal sealed in the region enclosed by the sealing member; and a connecting member for electrically connecting the array and filter substrates together in the peripheral portions thereof outside the sealing member. Here, a black matrix made of a metal and constituting part of the color filter and the opposing electrode are electrically connected together, and the black matrix and the opposing electrode are both so formed as to reach the peripheral portion of the filter substrate. Moreover, a region that is not covered by the opposing electrode is secured in the shape of a loop on the black matrix. The sealing member is arranged in this loop-shaped region.
Preferably, the black matrix is so formed as to be kept in direct contact with the opposing electrode.
Preferably, the opposing electrode is formed on the black matrix in a peripheral portion thereof outside the sealing member.
Preferably, the array substrate has, in a portion thereof lying inside the peripheral portion thereof, demarcated regions demarcated by a plurality of scanning conductors and signal-transfer conductors, and the display elements are each composed of a transistor and a pixel electrode, and are arranged individually in the demarcated regions. Moreover, the black matrix has openings formed therein so as to correspond to the demarcated regions, and the color filter adopts a stripe arrangement in which the openings located along each signal-transfer conductor are covered with color elements of an identical color, with grooves formed at boundaries between color elements of an identical color so that the black matrix is exposed through the grooves.
Preferably, the array substrate has, in a portion thereof lying inside the peripheral portion thereof, demarcated regions demarcated by a plurality of scanning conductors and signal-transfer conductors, and the display elements are each composed of a transistor and a pixel electrode, and are arranged individually in the demarcated regions. Moreover, the transistors and the pixel electrodes are arranged directly on a transparent substrate of the array substrate.
REFERENCES:
patent: 5488498 (1996-01-01), Fujii et al.
patent: 6022646 (2000-02-01), Kim et al.
patent: 63-287821 (1988-11-01), None
patent: 2-234122 (1990-09-01), None
patent: 6-301045 (1994-10-01), None
patent: 08-122824 (1996-05-01), None
patent: 408278499 (1996-10-01), None
patent: 40833478 (199
Ikemoto Takashi
Kametani Masayuki
Kanazawa Hideto
Kinoshita Takuo
Marukawa Yasuo
Ngo Julie
Rader Fishman & Grauer
Sanyo Electric Co,. Ltd.
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