Liquid crystal cells – elements and systems – Particular structure – Having significant detail of cell structure only
Reexamination Certificate
1999-07-13
2001-11-27
Parker, Kenneth (Department: 2871)
Liquid crystal cells, elements and systems
Particular structure
Having significant detail of cell structure only
C349S138000, C349S153000
Reexamination Certificate
active
06323924
ABSTRACT:
BACKGROUND OF INVENTION
The present invention relates to a liquid crystal display device, and more particularly, to a liquid crystal display device which prevents stripping or corrosion of a wiring layer formed on a peripheral portion of an insulative substrate.
FIG. 1
is a schematic block diagram of a conventional active matrix type liquid crystal display device. The pixel portion (display panel)
101
comprises a plurality of scanning lines (gate wiring) G
1
-Gm, a plurality of data lines (drain wiring) D
1
-Dm crossing orthogonally with the gate wiring G
1
-Gm, and pixels
102
provided at each of the intersections of the gate wirings and the drain wirings. A gate signal (a scanning signal) from a gate driver
103
is applied to the gate wirings G
1
-Gm A data signal (a video signal) from a drain driver (data driver )
104
is applied to the drain wirings D
1
-Dm. The gate and drain drivers
103
and
104
form a peripheral driver circuit
105
. A liquid crystal display device which comprises the driver
103
or
104
and the pixel portion
101
formed on an insulative substrate
11
(
FIG. 3
) is generally called a driver built-in liquid crystal display device. The gate driver
103
may be provided on both sides of the pixel portion
101
. The drain driver
104
may be provided on both sides of the pixel portion
101
.
FIG. 2
is an equivalent circuit diagram of one of the pixels
102
. The pixel
102
comprise an TFT (Thin Film Transistor)
106
as a pixel drive element, a liquid crystal cell LC and a supplementary capacitor (a storage capacitor or an additional capacitor) SC. The gate wiring Gn is connected to the gate of the TFT
106
, and the drain wiring Dn is connected to the drain of TFT
106
. The source of the TFT
106
is connected to the supplementary capacitor SC and a display electrode (pixel electrode)
107
of the liquid crystal cell LC. The liquid crystal cell LC and the supplementary capacitor SC form a signal storage element. An opposite electrode (common electrode)
108
, which is arranged opposite to the display electrode
107
of the liquid crystal cell LC, receives a voltage Vcom. The supplementary capacitor SC comprises a storage electrode
109
connected to the source of the TFT
106
and a supplementary capacitor electrode
110
to which a constant voltage VR is applied. The opposite electrode
108
of the liquid crystal cell LC is common to all of the pixels
102
. Static capacity is formed between the display electrode
107
and the opposite electrode
108
. The supplementary capacitor electrode
110
may be alternatively connected to the adjacent gate wiring Gn+1.
FIG. 3
is a partial cross sectional view of the conventional display panel
101
. A liquid crystal layer
13
is provided between opposing first and second insulative substrates
11
and
12
which are preferably made of transparent glass material. An aluminum alloy film
14
which forms a wiring layer, a planarizing insulation film
15
preferably made of acrylic resin and an orientation film
16
preferably made of polyimide resin are laminated on the first substrate
11
. An opposite electrode
17
(i.e., the opposite electrode
108
) preferably made of ITO (Indium Tin Oxide) and a second orientation film
18
preferably made of polyimide resin are laminated on the second substrate
12
. A sealing material
19
preferably an epoxy resin is provided between the insulative substrates
11
and
12
to prevent leakage of the liquid crystal layer
13
. Specifically, the sealing material
19
is provided between the orientation films
16
and
18
at the peripheral portions of the substrates
11
and
12
.
On the peripheral portions of the insulative substrates
11
and
12
to which the sealing material
19
is provided, the aluminum alloy film
14
is formed all over the first insulative substrate
11
. Adhesion strength of the aluminum alloy film
14
to the planarizing insulation film
15
is lower than that of the planarizing insulation film
15
to the insulative substrate
11
. Therefore, the planarizing insulation film
15
may easily peel off the aluminum alloy film
14
.
FIG. 4
is a partial cross sectional view of a second conventional liquid crystal display device in which the aluminum alloy film
14
is formed as a lead wiring on the peripheral portion of the insulative substrate
11
. The sealing material
19
is formed between the opposite electrode
17
and the planarizing insulation film
15
to enclose liquid crystal layer
13
and the orientation films
16
and
18
at the peripheral portions of the insulative substrates
11
and
12
.
A portion of the aluminum alloy film
14
forms a contact pad
20
The contact pad
20
may be made of a different material from the aluminum alloy film
14
. The opposite electrode
17
is formed to extend to the edge of the substrate
12
, and an extended portion of the opposite electrode
17
is connected to the contact pad
20
via a conductive material
21
. The conductive material
21
is preferably made of resin mixed with conductive material. The contact pad
20
receives a voltage Vcom via the input terminal (not shown) of the lead wiring of the aluminum alloy film
14
. The voltage Vcom is applied to the opposite electrode
17
via the conductive material
21
.
Various input terminals (a power supply input terminal of voltage Vcom or VR, a power supply input terminal of the peripheral drive circuit
105
and an input terminal of the data signal) are concentrated on the lead wiring of the aluminum alloy film
14
. The arrangement of the input terminals facilitates drawing wirings of an equipment when the liquid crystal display device is mounted into various apparatus, such as a personal computer, a word processor, an electronic notebook, or a television display monitor.
The area of the contact pad
20
provided on the peripheral portion of the insulative substrate
11
is larger than the area necessary to connect the liquid crystal display device with an external circuit and is exposed out of the peripheral portion of the substrate
11
. If the exposed portion of the contact pad
20
is exposed to air, it may cause corrosion of the aluminum alloy film
14
of the contact pad
20
. Moreover, moisture or contaminants in the air may penetrate between the contact pad
20
and the conductive material
21
, adversely affecting the liquid crystal layer
13
and the TFT
106
.
It is an object of the present invention to provide a liquid crystal display device which prevents stripping of the insulation film from the wring layer.
It is a secondary object of the present invention to provide a liquid crystal display device which prevents corrosion of the wiring layer and penetration of moisture or contaminants.
SUMMARY OF THE INVENTION
Briefly stated, the present invention provides a liquid crystal display device. The liquid crystal display device includes first and second insulative substrates arranged opposite to each other. A liquid crystal layer is provided between the first and second insulative substrates. A supplementary layer is located on the first insulative substrate. The supplementary layer has at least one slit formed near a peripheral portion thereof which exposes a portion of the first insulative substrate. A planarizing insulation film is located on the supplementary layer and on the exposed portion of the first insulative substrate. A sealing material is provided between the planarizing insulation film and the second insulative substrate to seal the liquid crystal layer.
The present invention provides a liquid crystal display device including first and second insulative substrates arranged opposite to each other. A crystal layer is provided between the first and second insulative substrates. A wiring layer is located on the first insulative substrate. A contact pad is located on a peripheral portion of the first insulative substrate and electrically connected to the wiring layer. A common electrode is located on the second insulative substrate. A conductive material is provided between the first and second insulative
Matsuoka Hideki
Nakano Minoru
Noritake Kazuto
Oima Susumu
Oku Norio
Parker Kenneth
Qi Mike
Sanyo Electric Co,. Ltd.
Sheridan & Ross P.C.
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