Liquid crystal cells – elements and systems – Nominal manufacturing methods or post manufacturing...
Reexamination Certificate
2002-04-22
2004-08-10
Nguyen, Dung T. (Department: 2871)
Liquid crystal cells, elements and systems
Nominal manufacturing methods or post manufacturing...
C349S158000, C225S096500, C083S885000
Reexamination Certificate
active
06774978
ABSTRACT:
This application claims the benefit of the Korean Patent Application No. P2002-07774 filed on Feb. 9, 2002, which is hereby incorporated by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a liquid crystal display panel, and more particularly, to a device for cutting a liquid crystal display panel and a method for cutting using the same to separate a unit liquid crystal display panel from the mother substrate.
2. Discussion of the Related Art
In general, a liquid crystal display device displays a desired picture by individually supplying a data signal according to picture information to the liquid crystal cell arranged in a matrix form and controlling light transmittance of the liquid crystal cells.
The liquid crystal display device includes a liquid crystal display panel on which liquid crystal cells of a pixel unit are arranged in a matrix form, and a driver integrated circuit (IC) for driving the liquid crystal cells.
The liquid crystal display panel includes a color filter substrate and a thin film transistor array substrate that are facing into each other and a liquid crystal filled between the color filter substrate and the thin film transistor array substrate.
On the thin film transistor array substrate of the liquid crystal display panel, there are a plurality of data lines for transmitting a data signal supplied from a data driver integrated circuit to the liquid crystal cell and a plurality of gate lines for transmitting a scan signal supplied from a gate driver integrated circuit to the liquid crystal cells. The liquid crystal cells are defined at each portion where the data lines and the gate lines cross each other.
The gate driver integrated circuit sequentially supplies a scan signal to the plurality of gate lines so that the liquid crystal cells arranged in a matrix form are sequentially selected line by line. A data signal is supplied from the data driver integrated circuit to the selected line of the liquid crystal cells.
Meanwhile, a common electrode and a pixel electrode are formed the color filter substrate and the thin film transistor array substrate to face into each other for applying an electric field to the liquid crystal layer.
The pixel electrode is formed by liquid crystal cells on the thin film transistor array substrate, while the common electrode is integrally formed on the entire surface of the color filter substrate.
Accordingly, by controlling a voltage applied to the pixel electrode while a voltage is applied to the common electrode, the light transmittance of the liquid crystal cells is individually controlled.
In order to control the voltage applied to the pixel electrode by each liquid crystal cell, a thin film transistor used as a switching device is formed at each liquid crystal cell.
To improve yield in fabricating a liquid crystal display device, a plurality of thin film transistor array substrates are formed on one large mother substrate, and a plurality of color filter substrates are formed on the other mother substrate. The two mother substrates are the attached to simultaneously form the plurality of liquid crystal display panels. Thus, a process for cutting the liquid crystal display panel into a plurality of unit panels is required.
Cutting the liquid crystal display panel is performed by a scribing process for forming a scribing line on the surface of the mother substrate with a pen made of diamond having a hardness higher than that of glass and a breaking process for cutting by applying a mechanical force along the scribing line.
The cutting process will now be described in detail with reference to the accompanying drawings.
FIG. 1
is a schematic plane view showing a unit liquid crystal display panel formed with a thin film transistor array substrate
1
and a color filter substrate
2
attached to face into each other.
In
FIG. 1
, the liquid crystal display panel
10
includes a picture display unit
13
having a plurality of liquid crystal cells arranged in a matrix form, a gate pad unit
14
connected to a plurality of gate lines of the picture display unit
13
, and a data pad unit
15
connected to the gate pad unit
14
and a plurality of data lines.
The gate pad unit
14
and the data pad unit
15
are formed at the marginal portion of the thin film transistor array substrate
1
. The portion does not overlap the color filter substrate
2
.
The gate pad unit
14
supplies a scan signal supplied from the gate driver integrated circuit to the gate lines of the picture display unit
13
. The data pad unit
15
supplies picture information supplied from the data driver integrated circuit to the data lines of the picture display unit
13
.
The data lines receiving the picture information and the gate lines receiving the scan signal are disposed to be crossed orthogonally on the thin film transistor array substrate
1
of the picture display unit
13
. At the crossed portion, a thin film transistor is formed for switching the liquid crystal cells, and a pixel electrode is formed to be connected to the thin film transistor for driving the liquid crystal cell. Further, a protective film is formed at the entire surface to protect the electrode and the thin film transistor.
At the color filter substrate
2
of the picture display unit
13
, a plurality of color filters are coated to be separated by cell regions with a black matrix, and a common transparent electrode to the pixel electrode are formed at the thin film transistor array substrate
1
.
A cell gap is formed between the thin film transistor array substrate
1
and the color filter substrate
2
so that the two substrates are spaced apart and face into each other. The thin film transistor array substrate
1
and the color filter substrate
2
are attached by a sealant (not shown) formed at the exterior of the picture display unit
13
. A liquid crystal layer (not shown) is formed at the space between the thin film transistor array substrate
1
and the color filter substrate
2
.
FIG. 2
is a cross-sectional view showing a plurality of unit liquid crystal display panels formed in the first mother substrate having the thin film transistor array substrates
1
and the second mother substrate with the color filter substrate
2
.
As shown in
FIG. 2
, a plurality of unit panels are formed in such a manner that one side of the thin film transistor array substrate
1
is protruded as much as a dummy region
31
.
This is because the gate pad unit
14
and the data pad unit
15
are formed at the marginal portion where the thin film transistor array substrate
1
and the color filter substrate
2
do not overlap.
Thus, the color filter substrate
2
formed on the second mother substrate
30
is formed to be isolated as much as dummy regions
31
corresponding to the area that the thin film transistor array substrates
1
formed on the first mother substrate
20
are protruded.
Each unit panel is disposed at the first and second mother substrates
20
and
30
so that the first and the second mother substrates
20
and
30
are used at the maximum. Depending on a model, the unit liquid crystal display panels are generally formed to be isolated as much as the dummy region
32
.
After the first mother substrate
20
where the thin film transistor array substrates
1
are formed and the second mother substrate
30
, where the color filter substrates
2
are formed, are attached each other, the liquid crystal display panels are individually cut through the scribing process and the breaking process. The dummy regions
31
formed at the region where the color filter substrates
2
of the second mother substrate
30
are isolated. The dummy region
32
isolating the unit panels are simultaneously removed.
The cutting process to the unit panels will now be described with reference to
FIGS. 3A
to
3
J.
As shown in
FIG. 3A
, the first mother substrate
20
and the second mother substrate
30
are loaded on a first table
33
.
Next, as shown in
FIG. 3B
, the first table
33
is moved in one direction to sequentially form a plurality of
LG.Philips LCD Co. , Ltd.
Morgan & Lewis & Bockius, LLP
Nguyen Dung T.
Schechter Andrew
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