Liquid crystal cells – elements and systems – Particular excitation of liquid crystal – Electrical excitation of liquid crystal
Reexamination Certificate
1998-05-26
2002-05-21
Sikes, William L. (Department: 2164)
Liquid crystal cells, elements and systems
Particular excitation of liquid crystal
Electrical excitation of liquid crystal
C349S054000, C349S192000
Reexamination Certificate
active
06392719
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a liquid crystal display (LCD) device and more particularly, to an LCD device in which a shorting bar of a data line is divided to improve accuracy in testing and measuring a cell.
2. Discussion of the Related Art
Generally, in the fabricating process steps of an LCD device, undesired static electricity is produced and subsequently is applied to the inside of a thin film transistor TFT-LCD array. The discharging of the static electricity can destroy a device such as a TFT. To prevent the inner device from being destroyed by static electricity discharge and also to facilitate TFT-LCD array testing, after formation of the TFT-LCD array, a shorting bar is utilized.
A conventional LCD device including a shorting bar will now be described with respect to the accompanying drawings.
FIG. 1
is a schematic layout of a conventional LCD device.
FIG. 2
is a schematic layout illustrating an interconnection relationship between a data line and a shorting bar of FIG.
1
.
The conventional TFT-LCD array, as shown in
FIG. 1
, includes a plurality of gate lines
1
a
and
1
b
formed at predetermined intervals in one direction and a plurality of data lines
2
a
and
2
b
formed at predetermined intervals in a direction perpendicular to the plurality of gate lines
1
a
and
1
b.
As shown in
FIG. 1
, a pixel electrode (not shown) is formed at each pixel region where the gate lines
1
a
and
1
b
cross the data lines
2
a
and
2
b
. A TFT
3
is formed, at each line and gate crossing and applies picture signals of the data lines
2
a
and
2
b
to the pixel electrode. The picture signals correspond to driving signals of the gate lines
1
a
and
1
b.
A plurality of shorting bars
4
,
5
,
6
, and
7
are formed around the TFT-LCD array. The plurality of gate lines
1
a
and
1
b
and the plurality of data lines
2
a
and
2
b
are divided into even and odd numbered lines. The first shorting bar
6
is connected to each of the data lines
2
a
, and are designated as the even numbered data lines. The second shorting bar
7
is connected to each of the data lines
2
b
and are designated as the odd numbered data lines. The third shorting bar
4
is connected to the gate lines
1
a
which are designated as the even numbered gate lines. The fourth shorting bar
5
is connected to the gate lines
1
b
which are designated as the odd numbered gate lines.
The interconnection relationship between the data lines
2
a
and
2
b
and the shorting bars
6
and
7
, of the LCD device of
FIG. 1
, will now be described with reference to FIG.
2
.
As shown in
FIG. 2
, the first shorting bar
6
is integrally formed with the data line
2
a
and is composed of the same material as data lines
2
a
and
2
b
. Similarly (although not shown), the second shorting bar
7
is composed of the same material as gate lines
1
a
and
1
b
and is integrally formed with gate lines
1
a
and
1
b
. The second shorting bar
7
and the data line
2
b
are connected to each other by a transparent electrode
9
.
The shorting bars
4
,
5
,
6
, and
7
in the conventional LCD device are used to prevent an inner device from being destroyed because of an electro-static discharge. Static electricity is produced during the course of manufacture of the TFT-LCD array and during the testing of the TFT-LCD array to determine whether or not the gate lines and the data lines have been shorted out. The testing is accomplished by maintaining an equipotential voltage between the data lines.
In other words, a power source is applied to the shorting bars which are connected to one end of each of the gate lines, the other end of each of the gate line is then checked to determine whether or not the gate lines are shorted out. In a similar manner, as employed for the gate lines, the data lines are tested to determine whether or not the data lines are shorted out.
The shorting bars are not an active element of the TFT-LCD array. The shorting bars are only used in testing the TFT-LCD. array and the prevention of destructive discharges of accumulated static electricity. After forming the TFT-LCD array and testing the same, an upper plate and lower plate of the TFT-LCD are adhered to each other. The shorting bars are then removed by scribing and grinding processes.
The conventional LCD device has several problems. Since the gate lines
1
a
and
1
b
and the data lines
2
a
and
2
b
are divided into odd numbered lines and even numbered lines, respectively, and the shorting bars are formed at each of the gate lines and data lines to test the TFT-LCD array and prevent the destructive discharge of static electricity, respectively, it is difficult to check characteristics of the R (Red), G (Green), and B (Blue) colors when testing the TFT-LCD array. In other words, since the shorting bar is formed by dividing each of the data lines, it is difficult to separately check the characteristics of each of the R, G, and B colors.
Furthermore, the first shorting bar
6
is integrally formed with the data line and is formed of the same material as the data line. The second shorting bar
7
is formed of the same material as the gate line and connected to the data line by means of the transparent electrode
9
. With this configuration, it is likely that if a poor image occurs it is probably due to resistance differences between the first shorting bar
6
and the data line and between the second shorting bar
7
and the data line.
SUMMARY OF THE INVENTION
Accordingly, the present invention is directed to an LCD device that substantially obviates one or more of the problems due to limitations and disadvantages of the related art.
An object of the present invention is to provide an LCD device which reduces damage due to a destructive discharge of static electricity, which occurs in the course of manufacturing, and testing of a TFT-LCD array.
A further object of the present invention is to improve the accuracy of cell testing by dividing a shorting bar of a data line into three segments.
Additional features and advantages of the invention will be set forth in the description which follows, and in part will be apparent from the description, or may be learned by practice of the invention. The objectives and other advantages of the invention will be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings.
To achieve these and other advantages and in accordance with the purpose of the present invention, as embodied and broadly described, an LCD device according to the present invention includes a plurality of gate lines formed at predetermined intervals in one direction, a plurality of data lines formed at predetermined interval in a direction perpendicular to the plurality of gate lines, a first shorting bar connected to (3n-2)th data lines of the plurality of data lines, a second shorting bar connected to (3n-1)th data lines of the plurality of data lines wherein n is a natural number, and the first and third shorting bars are adapted to prevent static electricity, and a third shooting bar connected to (3n)th data lines of the plurality of data lines.
It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are intended to provide further explanation of the invention as claimed.
REFERENCES:
patent: 5668032 (1997-09-01), Holmberg et al.
patent: 5859679 (1999-01-01), Song
patent: 6014191 (2000-01-01), Kim et al.
patent: 6111621 (2000-08-01), Kim et al.
patent: 5-333329 (1993-12-01), None
patent: 8-201843 (1996-08-01), None
Chowdhury Tarifur R.
LG Electronics Inc.
Morgan & Lewis & Bockius, LLP
Sikes William L.
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