Liquid crystal cells – elements and systems – Particular structure – Having significant detail of cell structure only
Reexamination Certificate
2002-12-12
2004-08-10
Dudek, James A. (Department: 2871)
Liquid crystal cells, elements and systems
Particular structure
Having significant detail of cell structure only
C349S190000
Reexamination Certificate
active
06774972
ABSTRACT:
This application claims the benefit of the Korean Application No. P2001-88452 filed on Dec. 29, 2001, 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 liquid crystal displays and a method for fabricating the same, and more particularly to a liquid crystal display and a method for fabricating a liquid crystal display, wherein adhesive characteristics of a sealant arranged between two substrates is enhanced.
2. Background of the Related Art
Compared to cathode-ray tubes (CRTs), flat panel displays (e.g., liquid crystal displays (LCDs), plasma display panels (PDPs), field emission displays (FEDs), etc.) display high quality images, consume a relatively low amount of power, produce a low amount of heat, and may be fabricated in small sizes. Due to these characteristics, LCDs in particular are extensively used in devices such as watches, calculators, personal digital assistants (PDAs), cellular phones, notebook computers, monitors for personal computers (PCs), televisions, TV receivers, monitors in airplanes, etc.
LCDs typically include a liquid crystal display panel for displaying a picture and a driving circuit for providing driving signals to the liquid crystal display panel. The liquid crystal display panel includes first and second glass substrates bonded to, and spaced apart from each other by a cell gap into which a layer of liquid crystal material is injected.
The first glass substrate (i.e., the TFT array substrate) supports a plurality of gate lines arranged at a fixed interval and oriented along a first direction, a plurality of data lines arranged at a fixed interval and oriented along a second direction, perpendicular to the first direction, a plurality of pixel electrodes arranged in a matrix pattern at pixel regions where the plurality of gate and data lines cross each other, and a plurality of switching devices (e.g., thin film transistors) responsive to signals supplied from gate lines for switching signal supplied from corresponding data lines and for transmitting the switched signals to corresponding pixel electrodes.
The second glass substrate (i.e., the color filter substrate) supports a black matrix layer for shielding light from parts excluding the pixel regions, an RGB color filter layer for transmitting light at predetermined wavelengths to thereby display colors, and a common electrode.
The first and second substrates are bonded together with sealant, the cell gap is maintained by spacers, and the layer of liquid crystal material is injected into the cell gap between the two substrates.
Sealants are typically provided as thermosetting or photosetting sealants. Typical thermosetting sealants are formed of a mixture of an epoxy resin and an amine or an amide curing agent. Thermosetting sealants are capable of bonding the two substrates when heated at approximately 100° C. for about one hour. Typical photosetting sealants include UV photosetting sealants and are formed of a mixture of an acrylate resin and a photosetting agent capable of forming radicals when exposed to UV light. Photosetting sealants are capable of bonding the two substrates when exposed to UV light for approximately 30 seconds.
The aforementioned sealants have excellent adhesive characteristics when bonded to glass substrates, but relatively poor adhesive characteristics when bonded to organic films. Nonetheless, organic films are used as protection films in reflective or semi-transmissive LCDs and in providing large aperture LCDs. In order to enhance the adhesive characteristics of sealants within large aperture LCDs containing an organic protection film, a portion of the organic protection film located under where the sealant is to be formed is removed. Accordingly, the sealant may contact the glass substrates and bond the two substrates together via strong adhesive characteristics.
FIG. 1
illustrates a related art LCD and a method for fabricating the LCD.
Referring to
FIG. 1
, though not shown, the first glass substrate
100
supports a plurality of gate lines arranged at a fixed interval and oriented along a first direction, a plurality of data lines arranged at a fixed interval and oriented along a second direction, perpendicular to the first direction, a plurality of pixel electrodes arranged in a matrix pattern at pixel regions where the plurality of gate and data lines cross each other, and a plurality of switching devices (e.g., thin film transistors) responsive to signals supplied from gate lines for switching signal supplied from corresponding data lines and for transmitting the switched signals to corresponding pixel electrodes.
Though not shown, the second glass substrate
150
supports a black matrix layer
130
for shielding a light from parts excluding the pixel regions, an RGB color filter layer for transmitting light at predetermined wavelengths to thereby display colors, and a common electrode.
A sealant
110
is coated on a periphery of the first or second glass substrate
100
or
150
for bonding the two substrates together. The black matrix layer
130
is arranged between an active display region
120
and the sealant
110
.
Referring to
FIG. 1
, the first glass substrate
100
is formed larger than the second glass substrate
150
and a plurality of gate PAD connection lines
103
and a plurality of data PAD connection lines
104
are formed for applying signals to the plurality of gate and data lines, respectively.
Components are mounted on gate and data PCBs
105
and
106
, respectively, are formed outside the first substrate
100
. The components on the PCBs generate input signals (e.g., control signals, power signals, data signals, etc.) to a gate driver IC
107
a
and a data driver IC
107
b
included within gate and data TCPs
101
and
102
, respectively. The gate and data driver ICs
107
a
and
107
b
, respectively, provide voltages to the gate and data lines, respectively. Connected to the gate PAD connection lines
103
and the data PAD connection lines
104
, the gate and data TCPs
101
and
102
receive signals from the gate PCD
105
and the data PCB
106
, respectively, and provide signals to the gate and data lines.
FIG. 2A
illustrates a sectional view of area “E” shown in FIG.
1
.
FIG. 2B
illustrates a back side view of the first glass substrate
100
having the sealant, PAD connection lines, and protection film coated thereon in area shown in FIG.
2
A.
As described above, adhesive characteristics of the sealant are greater with respect to glass substrates than to organic films. In order to enhance adhesive characteristics between bonded substrates including an organic protection film
108
, a portion of the organic protection film
108
, located under where the sealant
110
is to be formed, is removed thereby allowing the sealant
110
to directly contact the first glass substrate
100
.
Referring to
FIGS. 2A and 2B
, the gate PAD connection lines
103
are formed on the first glass substrate
100
and the data PAD connection lines
104
are formed on a gate insulating film (not shown) also formed on the first glass substrate
100
. The organic protection film
108
, being an insulating film, is formed over an entire surface of the first substrate
100
, including the gate and data PAD connection lines
103
and
104
.
The gate insulating film (not shown) and the organic protection film
108
are is selectively removed to expose portions of the first glass substrate
100
between the gate and data PAD connection lines, thereby forming opened areas
109
. The sealant
110
is then coated on the organic protection film
108
such that the sealant
110
directly contacts the first glass
100
substrate at the opened areas
109
.
Since thermosetting and photosetting sealants have better adhesive characteristics with glass substrates compared to the organic protection film
108
, the opened area
109
allows the sealant
110
to directly contact the first glass substrate
100
and maximize the adhesive characteristic
Dudek James A.
LG.Philips LCD Co. , Ltd.
McKenna Long & Aldridge LLP
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