Liquid crystal cells – elements and systems – Particular structure – Having significant detail of cell structure only
Reexamination Certificate
1998-03-27
2002-06-04
Sikes, William L. (Department: 2871)
Liquid crystal cells, elements and systems
Particular structure
Having significant detail of cell structure only
C349S123000, C349S153000, C349S158000
Reexamination Certificate
active
06400438
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a mother glass board used to produce a plurality of transparent insulator substrates.
Referring to
FIG. 1
, a conventional circuit configuration of an active matrix type liquid crystal display (LCD)
100
will now be described. The LCD
100
comprises a display panel
101
, a gate driver
103
and a drain (data) driver
104
.
The display panel
101
has a plurality of gate wirings (scanning lines) G
1
−Gn and Gn+1−Gm and a plurality of drain wirings (data lines) D
1
−Dn and Dn+1−Dm. The gate wirings G
1
−Gm and drain wirings D
1
−Dm orthogonally cross forming pixel
102
at each point of intersection. The gate driver
103
is connected to the gate wirings G
1
−Gm to supply a gate signal (a scanning signal) thereto. The drain (data) driver
104
is connected to the drain wirings D
1
−Dm to supply a data signal (a video signal) thereto.
The drivers
103
and
104
form a peripheral drive circuit
105
. A liquid crystal display, which includes the display panel
101
and at least one of the drivers
103
and
104
formed on an insulator substrate, is generally called a driver built-in liquid crystal display. The gate driver
103
or drain driver
104
may be provided on both sides of the display panel
101
.
FIG. 2
shows an equivalent circuit for the pixels
102
. Each pixel
102
comprises a TFT (Thin Film Transistor)
106
, a liquid crystal cell LC and a supplemental capacitor (a storage or added capacitor) SC. The TFT
106
comprises a gate connected to the gate wiring Gn, a drain connected to the drain wiring Dn and a source connected to the supplemental capacitor SC and a display electrode (pixel electrode)
107
of the liquid crystal cell LC. The liquid crystal cell LC and supplemental capacitor SC form a signal storage element.
The liquid crystal cell LC has the display electrode
107
and an opposite electrode
17
. The opposite electrode
17
is applied to a voltage of Vcom. The opposite electrode
17
is common to all of the pixels
102
and is also called a common electrode. The display electrode
107
and the opposite electrode
17
produce capacitance therebetween. The supplemental capacitor SC comprises a storage electrode
109
connected to the source of TFT
106
and a supplemental capacitor electrode
110
. A constant voltage VR is applied to the supplemental capacitor electrode
110
. The supplemental capacitor electrode
110
may be connected to the gate wiring Gn+1 adjacent to Gn.
Referring to
FIG. 3
, a partial cross-sectional view of the LCD
100
will now be described. The LCD
100
comprises opposing transparent insulator substrates
11
and
12
, which are preferably made of glass material. A liquid crystal layer
13
filled with liquid crystal is provided between the substrates
11
,
12
. An aluminum alloy film
14
forming a wiring layer, an inter-layer insulating film
15
and an orientation film
16
which is preferably made of polyimide resin are laminated in the substrate
11
. On the substrate
12
, the opposite electrode
17
preferably made of an ITO (Indium Tin Oxide) film is formed, and a second orientation film
18
preferably made of polyimide resin is laminated.
Between the orientation films
16
and
18
on the peripheral portion of the insulated substrates
11
and
12
, a sealing material
19
preferably made of epoxy resin is provided to prevent leakage of the liquid crystal of the liquid crystal layer
13
.
A part of the aluminum alloy film
14
extends to the edge of the substrate
11
and forms a contact pad
20
. The contact pad
20
may be a laminate of ITO and chromium (Cr) and be different from the film
14
. A part of the opposite electrode
17
extends to the edge of the substrate
12
and forms a contact portion
22
. The contact portion
22
is connected to the contact pad
20
with a conductive material
21
. The voltage Vcom is applied to the contact pad
20
. The voltage Vcom is supplied from the film
14
to the opposite electrode
17
via the conductive material
21
and the contact portion
22
. The conductive material
21
is preferably made of resin mixed with conductive material.
As described above, the opposite electrode
17
formed on the peripheral portion of the substrate
12
is connected to the contact pad
20
formed on the border of the insulator substrate
11
via the conductive material
21
. This arrangement facilitates wirings when mounting the liquid crystal display in various apparatus, such as a personal computer, a word processor, or an electronic notebook, using the contact pad
20
as a pad for the voltage Vcom, a power supply pad VR, a power supply pad for the peripheral drive circuit
105
, and an input pad for a data signal. A plurality of the insulator substrates
11
and
12
are produced from one large plate glass (a mother glass board).
As shown in FIG.
4
(
a
), a plurality of the insulator substrates
12
(
12
a
-
12
d
) are formed in square formation regions arranged in a matrix form on a mother glass board
31
. The contact portions
22
of the opposite electrodes
17
of the adjacent substrates
12
a
-
12
d
are connected to one another on the mother glass board
31
. The board
31
is cut along the dotted line in FIG.
4
(
a
) to provide separate insulator substrates
12
, as shown in FIG.
4
(
b
). When the substrates
12
a
-
12
d
are cut from the mother glass board
31
, the continued contact portions
22
of the opposite electrodes
17
are also cut off. Consequently, the edges of the contact portions
22
of the opposite electrodes
17
are exposed of extend outward from the border of the insulator substrate
12
.
When the insulator substrates
12
a
-
12
d
are cut away from the mother board, adhesion of the contact portions
22
to the substrates
12
is decreased by the stress applied to the mother board
31
, especially by the external force concentrated at the periphery of the substrates
12
a
-
12
d
. This permits moisture or contaminants to intrude into a clearance between the contact portions
22
and the substrates
12
, decreasing the display performance and reliability. Moreover, such contaminants may corrode the opposite electrodes
17
and affect the liquid crystal layer
13
and the TFT
106
.
Accordingly, it is an object of the present invention to provide a mother glass board for fabricating a liquid crystal display with improved reliability.
SUMMARY OF THE INVENTION
To achieve the above objective, the present invention provides a glass board for forming a plurality of liquid crystal display panels, comprising: a plurality of insulating substrates; an electrode formed on each of the insulating substrates, each of the electrodes having a main body portion, a peripheral edge and at least one contact portion extending from the peripheral edge, wherein the contact portions of adjacent insulating substrates are spaced from each other by a predetermined distance.
The present invention further provides a glass board for forming a plurality of liquid crystal display panels, comprising: a plurality of insulating substrates; an electrode formed on each of the insulating substrates, each of the electrodes having a main body portion, a peripheral edge and at least one contact portion extending from the peripheral edge, wherein the contact portions of adjacent insulating substrates are spaced from each so that when the insulating substrates are separated from each other, adhesion of the contact portions to their respective substrate is not compromised.
The present invention further provides a liquid crystal display apparatus comprising: a substrate; and a common electrode for liquid crystal cells located on the substrate within each formation region; wherein an end of each common electrode is located within the associated formation region such that adjacent ends of adjacent substrates are spaced from each other.
Other aspects and advantages of the invention will become apparent from the following description taken in conjunction with the accompanying dra
Kawabe Masahiko
Matsuoka Hideki
Nakano Minoru
Noritake Kazuto
Chowdhury Tarifur R.
Sanyo Electric Co,. Ltd.
Sheridan & Ross P.C.
Sikes William L.
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