Liquid crystal cells – elements and systems – Nominal manufacturing methods or post manufacturing...
Reexamination Certificate
1999-01-14
2001-10-02
Sikes, William L. (Department: 2871)
Liquid crystal cells, elements and systems
Nominal manufacturing methods or post manufacturing...
C349S189000, C349S190000
Reexamination Certificate
active
06297869
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a liquid crystal display panel, and more particularly to a structure of an upper and lower substrates of the liquid crystal display panel which is cut into an unit panel before a liquid crystal is introduced between the upper and lower substrates integrated with each other. Further, the present invention relates to a manufacturing the liquid crystal display panel which is capable of being cut by a laser light.
2. Description of the Prior Art
Recently, a liquid crystal display (hereinafter, referred to as a LCD) module is widely used as a display unit instead of a cathode ray tube, because of its small size, light weight, and low consumption of power. The LCD module is a plan display unit using a liquid crystal as a light shutter transmitting and screening a transmission of the light, according to the electric signal.
A thin film transistor LCD module (hereinafter, referred to as TFT LCD module) is provided with a TFT substrate, a color filter substrate, and a liquid crystal introduced between the TFT substrate and the color filter substrate. The TFT substrate and the color filter substrate are made of two parent glass substrates which are respectively divided into six LCD panels.
The parent glass substrate which is used for the TFT substrate has a plurality of gate lines, a plurality of data lines which are respectively intersected with each gate line, TFT devices respectively formed at each intersection of the gate lines and the data lines, and pixel electrodes.
Another parent glass substrate which is used for the color filter substrate includes color filter layers respectively having red, green, and blue, a black matrix, and corresponding electrodes. The black matrix prevents a mixture of light in the color filter layers and keeps the thin film transistors from operating in an off-state.
The TFT substrate and the color filter substrate as constructed above are arranged, assembled together and cut along a cutting line into a plurality of the LCD panels before the liquid crystal is introduced between the substrates.
FIGS. 1 and 2
are views showing processes of cutting the integrated substrate by using a diamond scriber and attaching a polarizing plate to the substrate.
Referring to
FIG. 1
, a method of manufacturing an LCD panel according to the conventional art includes a step ST
1
of integrating substrates, a step ST
2
of cutting the integrated parent substrates using the diamond scriber, a step ST
3
of filling the liquid crystal between the integrated substrates, a step ST
4
of sealing a liquid crystal introducing inlet of the integrated substrates, a step ST
5
of attaching the polarizing plates to outer surfaces of the integrated substrates, a step ST
6
of grinding a cut surface of the substrates using a grinder, and a step ST
7
of transferring the substrates to an assembling stage.
Referring to
FIG. 2
, a method of manufacturing an LCD panel according to another conventional art includes a step of cutting the integrated parent substrates using a diamond scriber, a step of filling the liquid crystal between the integrated substrates, a step of sealing a liquid crystal introducing inlet of the integrated substrates, a step of grinding a cut surface of the substrates using a grinder, a step of attaching the polarizing plates to outer surfaces of the integrated substrates, and a step ST
7
of transferring the substrates to an assembling stage.
Regarding methods of manufacturing the LCD panel according to the conventional art, at the grinding step, one of the integrated substrates is cut along cutting lines C
1
, C
2
and G
1
, and then has been grinded at a predetermined angle at the corner of cut surfaces thereof, as shown in
FIGS. 3 and 4
. In
FIGS. 3 and 4
, a reference numeral
14
denotes a short bar connecting gate lines
12
with each other and a reference numeral
16
indicates a short bar connecting data lines with each other. The short bars
14
and
16
discharge the static electricity generated while cutting the substrates.
The grinding step removes glass chips remaining at edges of the substrates from the substrates, prevents damage to a printed circuit board attached to a pad and protects the gate line, the data lines and the panel from cracking.
According to the method referred in
FIG. 1
, the glass chips around the edges of the substrates generated during the cutting step cause defects in attaching the polarizing plates to the substrates. The defect in the attachment of the polarizing plates forces the polarizing plates to be re-attached, which increases a manufacturing cost.
The method in which the substrate is ground before attaching the polarizing plates as referred in
FIG. 2
may remarkably reduce defects in the polarizing plate attachment. However, the removal of the short bar
14
from the substrates cut along the cutting line G
1
as shown in
FIGS. 3 and 4
, causes malfunction of the panel's TFTs due to the static charges due to a friction during the grinding step.
Referring to
FIG. 3
again, the cutting of the parent substrate using the laser light starts at an outer surface of the substrate. The parent glass substrate can be cut along the cutting lines, but the interconnection lines
12
formed on an inner surface of the substrate are occasionally not cut. As shown in
FIGS. 5
a
and
5
b,
even though the parent glass substrate
10
is exactly cut along the cutting lines C
1
and C
2
, the crack generated in the parent glass substrate
10
may not be transferred to the interconnection lines
12
disposed on the inner surface of the substrate and the interconnection lines
12
are not exactly cut.
It is considered that the cutting problems are caused by the ductility and heat expansion difference of metals used for the interconnection lines.
Sealant is coated on the inner surface of one substrate in order to integrate the substrates together.
FIG. 6
is a view showing the sealant coated on the substrate, the liquid crystal introducing inlet
37
, and the cutting line
39
a
on the substrate according to the present invention. Reference numerals
38
a,
38
b,
39
a,
and
39
b
respectively denote the cutting line and reference numeral
34
indicates the black matrix.
Referring to
FIG. 6
, a seal line formed on the substrate, except for the liquid crystal introducing inlet is not overlapped with the cutting line. However, a part of the seal line forming the liquid crystal introducing inlet extends across the cutting line
39
a.
Therefore, since the cutting line
39
a
near the liquid crystal introducing inlet
37
is cut under a cutting condition different from another cutting lines, it is difficult to cut the integrated substrate into a plurality of panels by laser. Thus, different cutting conditions for the portion near the liquid crystal introducing inlet and for the rest of the substrate have to be set up, which complicates the cutting process.
As shown in
FIG. 12
, in the case that the cutting line
39
a
extends across a neck portion of the liquid crystal introducing inlet
37
, there is a problem in that when the sealant
66
is supplied to close the liquid crystal introducing inlet
37
, air is introduced through the liquid crystal introducing inlet
37
into a liquid crystal layer between the integrated substrate
32
.
SUMMARY OF THE INVENTION
The present invention has been made to overcome the above described problems of the prior art.
It is an object of the present invention to provide a substrate for a liquid crystal display panel, in which glass chips are prevented from being created during a cutting of the substrate.
It is another object of the present invention to provide a liquid crystal display panel of which substrates are grinded without generating static charges. .
It is still an objet of the present invention to provide a method of manufacturing a liquid crystal display panel capable of being cut by a laser light, in which a conducting layer formed in an inner surface of a substrate can be prevented from being cut during
Choo Dae-ho
Jung Sung-Uk
Kim Bum-soo
Kim Byeong-ill
Lee Woo-shik
Chowdhury Tarifur R.
Howrey Simon Arnold & White , LLP
Samsung Electronics Co,. Ltd.
Sikes William L.
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