Liquid crystal cells – elements and systems – Particular excitation of liquid crystal – Electrical excitation of liquid crystal
Reexamination Certificate
1999-09-16
2002-12-17
Ton, Toan (Department: 2871)
Liquid crystal cells, elements and systems
Particular excitation of liquid crystal
Electrical excitation of liquid crystal
C349S187000, C438S030000
Reexamination Certificate
active
06496234
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a liquid crystal display, and more particularly, to a method of eliminating static electricity introduced from the exterior of the liquid crystal display (LCD).
2. Description of the Prior Art
Generally, static electricity is substantially stationary as an electric charge existing on a nonconductor and is produced by friction or an electrostatic induction, or other such conditions. Static electricity creates problems in a liquid crystal panel during a manufacturing process of the liquid crystal panel so as to cause a reduction in a manufacturing yield of the liquid crystal panel.
For instance, as shown in
FIG. 1
, the conventional liquid crystal panel includes a thin film transistor (TFT) matrix
20
formed on a lower glass substrate
10
, a shorting bar for gate lines
22
for testing gate lines of the TFT matrix
20
, and a shorting bar for data lines
24
for testing data lines of the TFT matrix
20
. The gate lines of the TFT matrix
20
are connected to the gate line shorting bar
22
via gate line test electrodes
16
while the data lines of the TFT matrix
20
are connected to the data line shorting bar
24
via data line test electrodes
18
.
The upper end of the lower glass substrate
10
is provided with a gate pad area
10
a
including a gate driving integrated circuit(IC), and the left end of the lower glass substrate
10
is provided with a data pad area
10
b
including a data driving IC. Further, the center of the lower glass substrate
10
is provided with the TFT matrix
20
switched by control signals and video signals of the gate and data driving ICs.
The shorting bars
22
and
24
are connected to the TFT matrix
20
to test a characteristic of the TFT. For this purpose, the shorting bars
22
and
24
are connected to the gate line test electrodes
16
and the data line test electrodes
18
, respectively, each of which is connected to the gate lines and the data lines of the TFT matrix
20
, thereby forming an electrical path along with the TFT matrix
20
. Also, the shorting bars
22
and
24
deliver a test signal from outside of the TFT matrix
20
into the interior of the TFT matrix
20
to test the TFT matrix
20
. Such a characteristic test of the TFT matrix
20
is carried out after the TFT matrix
20
has been formed on the lower glass substrate and before a liquid crystal material is disposed thereon. Since the shorting bars
22
and
24
can be formed on the gate pad area
10
a
and the data pad area
10
b
due to a structural characteristic of the LCD, the shorting bars
22
and
24
are located at the opposite edges of the gate pad area
10
a
and the data pad area
10
b
. Such a structural characteristic may be applied to a liquid crystal panel of a chip on glass (COG) type or a TFT panel manufactured by a low-temperature poly-silicon process.
A liquid crystal material layer
14
and an upper glass substrate
12
are sequentially disposed on the lower glass substrate
10
which has been determined to be normal by the test of the TFT matrix
20
as described above. The lower glass substrate
10
along with the liquid crystal material layer
14
and the upper glass substrate
12
disposed on the lower glass substrate
10
is cut off along lines A-A′ and B-B′ as shown in
FIG. 1
, thereby providing a liquid crystal panel shown in FIG.
2
.
However, the cut gate line test electrodes
16
and data line test electrodes
18
are exposed at the edge of the lower glass substrate
10
of the liquid crystal panel having a sequentially disposed structure as shown in FIG.
2
. The exposed test electrodes
16
and
18
apply static electricity from the exterior to the gate lines and data lines of the TFT matrix
20
, respectively. This application of static electricity causes damage to the TFTs included in the TFT matrix
20
. As a result, a stripe-shaped defect is generated at the liquid crystal panel and a manufacturing yield of the liquid crystal panel is reduced.
SUMMARY OF THE INVENTION
To overcome the problems described above, preferred embodiments of the present invention provide a method of manufacturing a liquid crystal panel so as to prevent an introduction of static electricity from the exterior of the liquid crystal panel.
In order to achieve these and other advantages provided by preferred embodiments of the present invention, a method according to one aspect of preferred embodiments of the present invention includes an etching step for removing the ends of test electrodes formed on a lower glass substrate on which a liquid crystal material layer and an upper glass substrate are disposed.
REFERENCES:
patent: 5445711 (1995-08-01), Tanski et al.
patent: 6310666 (2001-10-01), Moon
patent: 9416852 (1992-12-01), None
Birch & Stewart Kolasch & Birch, LLP
Duong Thoi Van
LG LCD Inc.
Ton Toan
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