Electricity: measuring and testing – Impedance – admittance or other quantities representative of... – Lumped type parameters
Reexamination Certificate
2002-10-01
2004-08-24
Zarneke, David A. (Department: 2829)
Electricity: measuring and testing
Impedance, admittance or other quantities representative of...
Lumped type parameters
Reexamination Certificate
active
06781402
ABSTRACT:
This application claims the benefit of the Korean Application No. P2002-011969 filed on Mar. 6, 2002, which is hereby incorporated by reference for all purposes as if fully set forth herein.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a liquid crystal display (hereinafter “LCD”) panel, and more particularly, to an apparatus and a method for testing a size of a unit LCD panel and status of cut surface after cutting LCD panels fabricated on a large mother substrate into individual unit LCD panels.
2. Discussion of the Related Art
In general, an LCD 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 through liquid crystal molecules of the liquid crystal cells.
In the LCD device, TFT (hereinafter “TFT”) array substrates are formed on a large mother substrate and color filter substrates are formed on an additional mother substrate. Then, by attaching the two mother substrates, a plurality of LCD panels are simultaneously formed. Because yield can be increased by simultaneously forming a plurality of LCD panels on a glass substrate of a large area, a process of cutting the attached two mother substrates into unit LCD panels is required.
Conventionally, the cutting processing includes forming a predetermined cutting line on the surface of the substrate with a pen having a higher hardness than the glass substrate and propagating a crack along the predetermined cutting line. The cutting process of the unit LCD panel will be described in detail with reference to the accompanied drawings.
FIG. 1
is a schematic plan view showing a unit LCD panel formed with a TFT array substrate and color filter substrate attached to face into each other.
In
FIG. 1
, the LCD 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 a plurality of data lines of the picture display unit
13
.
The gate pad unit
14
and the data pad unit
15
are formed at the marginal portion of the TFT array substrate
1
. The marginal 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 receive picture information and the gate lines receive the scan signal. The data lines and gate lines cross orthogonally on the TFT array substrate
1
of the picture display unit
13
. At each of the crossed portion, a thin film transistor (TFT) is formed for switching the liquid crystal cells that are defined by the crossing of the data and gate lines. A pixel electrode is formed in each liquid crystal cell to be connected to the TFT for driving the liquid crystal cell. Further, a protective film is formed over the entire surface to protect the pixel electrode and the TFT.
A plurality of color filters are formed on the color filter substrate
2
. The color filters for a cell region are separated from adjacent cell regions by a black matrix. Common transparent electrodes corresponding to the pixel electrodes are formed on the color filter substrate
2
.
A cell gap is formed between the TFT array substrate
1
and the color filter substrate
2
so that the two substrates are spaced apart and face each other. The TFT 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 in the space between the TFT array substrate
1
and the color filter substrate
2
.
FIG. 2
illustrates a cross-sectional view showing a plurality of unit LCD panels formed in the first mother substrate having the TFT array substrates and the second mother substrate having the color filter substrates.
As shown in
FIG. 2
, a plurality of unit LCD panels are formed in such a manner that one side of the unit LCD panel TFT array substrates
1
protrudes by as much as a dummy region
31
of the unit LCD panel color filter substrates.
The protrusion of the unit LCD panel is provided because the gate pad unit
14
and the data pad unit
15
are formed at the marginal portion provided by the protrusion where the TFT array substrates
1
and the color filter substrates
2
do not overlap.
Thus, the color filter substrates
2
formed on the second mother substrate
30
are formed to be isolated by as much as dummy regions
31
which correspond to the protrusions of the TFT array substrates
1
.
Each unit LCD panel is disposed at the first and second mother substrates
20
and
30
so that the area of the first and the second mother substrates
20
and
30
are used at the maximum. Depending on a model of unit LCD panel being fabricated, the unit LCD panels are generally formed to be isolated by as much as the second dummy regions
32
.
After the first mother substrate
20
where the TFT array substrates
1
are formed and the second mother substrate
30
where the color filter substrates
2
are formed are attached each other, the LCD panels are individually cut. The dummy regions
31
formed at the region where the color filter substrates
2
of the second mother substrate
30
are isolated and the second dummy regions
32
isolating the unit LCD panels, are simultaneously removed.
FIG. 3
is an exemplary view showing a testing apparatus for LCD panel according to related art.
As shown in
FIG. 3
, the testing apparatus comprises a first and a second testing bars
101
and
102
for testing the cutting status of longer sides of the unit LCD panel
100
(that is, a side where the data pad unit is formed and the opposite side of the unit LCD panel). A third and a fourth testing bars
103
and
104
for testing the cutting status of shorter sides of the unit LCD panel
100
(that is, a side where the gate pad unit is formed and the opposite of the unit LCD panel.
The first and second testing bars
101
and
102
test whether or not a burr remains on the longer sides of the unit LCD panel
100
in a touch method. The third and fourth testing bars
103
and
104
test whether or not a burr is remains on the shorter sides of the unit LCD panel
100
by the same method as the first and second testing bars
101
and
102
.
On the other hand, the size of the unit LCD panel
100
can be varied according to the models of unit LCD panel being fabricated. Therefore, the first and second testing bars
101
and
102
and the third and fourth testing bars
103
and
104
are formed to have same lengths as the longer sides and the shorter sides, respectively of the largest unit LCD panel
100
that may be fabricated, and thereby, the test can be performed for all models of unit LCD panel
100
.
Also, in the unit LCD panel
100
, a color filter substrate
120
is stacked on a TFT array substrate
110
, and two sides of the TFT array substrate
110
are formed to protrude beyond the color filter substrate
120
. This is because that the gate pad unit and data pad unit are formed on the TFT array substrate
110
in a marginal portion that does not overlap the color filter substrate
120
, as described with reference to FIG.
1
.
Therefore, one of the longer sides and one of the shorter sides of the unit LCD panel
100
have a step shape. The first testing bar
101
corresponds to the one of the longer sides of the unit LCD panel
100
on which the data pad unit is formed. The third testing bar
103
corresponds to the one of the shorter sides of the unit LCD panel
100
on which the gate pad unit is formed. Thus, to test the longer sides of the unit LCD panel
100
, the first testing bar
101
is formed to be engaged with the one of longer sides of the unit LCD panel
100
h
Shin Sang-Sun
Uh Ji-Heum
LG.Philips LCD Co. , Ltd.
McKenna Long & Aldridge LLP
Nguyen Trung Q.
Zarneke David A.
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