Liquid crystal cells – elements and systems – Particular excitation of liquid crystal – Electrical excitation of liquid crystal
Reexamination Certificate
2002-03-26
2003-11-11
Kim, Robert H. (Department: 2871)
Liquid crystal cells, elements and systems
Particular excitation of liquid crystal
Electrical excitation of liquid crystal
C349S054000, C349S192000
Reexamination Certificate
active
06646694
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a method of repairing broken lines and, more particularly, to a method of repairing LCD data lines.
2. Description of the Related Art
Liquid crystal display(LCD) devices are a well-known form of flat panel displays with advantages of low power consumption, lightweight, thin profile, and low driving voltage. The liquid crystal molecules change their orientations when an electronic field is applied. In the display region of the LCD, an array of pixel regions is patterned by horizontally extended gate lines and vertically extended data lines. Each pixel region has a thin film transistor (TFT) and a pixel electrode. The TFT serves as a switching device.
As described above, the TFT array substrate has wiring patterns such as the gate lines and data lines, that supply image signals to drive the pixel electrodes. However, the wiring patterns may easily disconnect if the regions they pass are not smooth or during the heat treatments or etching processes, resulting in open or short circuits. As size and resolution of LCD device continue to increase, large numbers of data lines and gate lines with a narrower line width are required on the TFT array substrate. The fabricating difficulties are also increased, causing a greater possibility of broken wiring patterns. Accordingly, it is desirable to provide a repair method that allows the LCD to operate despite broken wiring.
FIG. 1
is a top view showing a conventional method of repairing the disconnected data lines. On a TFT array substrate
10
of an LCD, a display region
20
has a plurality of horizontally extended gate lines
12
and a plurality of vertically extended data lines
16
to form an array of rectangular pixel regions
22
. The TFT array substrate
10
also includes a plurality of gate pads
14
at an end of each gate line
12
, and a plurality of data pads
18
at an end of each data line
16
. In addition, a plurality of repair lines
24
A,
24
B and
24
C are formed to cross the data lines
16
outside the display region
20
.
For example, when a broken point A interrupts the image signals passing through the broken data line
16
A, laser fusing or other conventional techniques can be used to connect points
26
a
and
26
b
where the broken data line
16
A meet the repair line
24
A, and the repair line
24
A is cut off at positions
28
a
and
28
b.
Therefore, image signals can go through the repair line
24
A to reach the broken point A. However, a capacitor is existed between the repair line
24
A and the data line
16
A, the image signals will be distorted at the intersecting point
26
a
or
26
b
when passing through the repair line
24
A. Particularly, as the number of data lines
16
increases, the number of the intersecting points also increase, and thus the increased capacitors worsen the signal quality. Moreover, depending on the location of the broken data line, a large delay may be incurred due to the resistance and capacitance of the repair line between opposite ends of the broken data line. This increased delay may be unacceptable for large, high-resolution LCD devices. In addition, a single data line is generally repaired using a single repair line and the number of repair lines
24
is limited due to the size of the display region
20
. Therefore, a method of repairing the broken data lines without fabricating repair lines to solve the aforementioned problems is called for.
SUMMARY OF THE INVENTION
The present invention provides a method of repairing broken data lines without fabricating extra wiring patterns outside the display region. The repairing method forms a repair line vertically across pixel regions.
On a flat display panel, a substrate has a first pixel region and a second pixel region formed by a first data line and a second data line extending vertically, and a first gate line and a second gate line extending horizontally. A first pixel electrode and a second pixel electrode are formed in the first pixel region and the second region respectively. An opening is formed between a first broken point and a second broken point of the first data line in the second pixel region. A method of repairing the first data line comprises steps of: electrically connecting the first data line and the first pixel electrode within the first pixel region; electrically connecting the first pixel electrode and the second pixel electrode; and electrically connecting the second pixel electrode and the second broken point of the first data line within the second pixel region.
Accordingly, it is a major object of the invention to use laser fusing to form an electrical connection across the first pixel electrode and the second pixel electrode.
It is another object of the invention to repair the line defect on the substrate without fabricating extra wiring patterns on the peripheral region of the pixel region.
Yet another object of the invention is to prevent signal distortion caused by the repair line positioned across the adjacent data lines.
It is a further object of the invention to provide the electric connection vertically across more than two pixel electrodes if more than one opening is found on the same broken data line.
Still another object of the invention is to prevent the increase in RC delay time caused by resistance and capacitance of the repair line.
Another object of the invention is to provide an unlimited number of repair lines irrespective of the space and size of the flat display panel.
These and other objects of the present invention will become readily apparent upon further review of the following specification and drawings.
REFERENCES:
patent: 5600460 (1997-02-01), Yamamoto et al.
patent: 6476882 (2002-11-01), Sakurai
patent: 2002/0140896 (2002-10-01), Lee
AU Optronics Corp.
Kim Robert H.
Ladas & Parry
Nguyen Dung
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