Liquid crystal cells – elements and systems – Particular structure – Having significant detail of cell structure only
Reexamination Certificate
2002-05-30
2004-07-06
Chowdhury, Tarifur R. (Department: 2871)
Liquid crystal cells, elements and systems
Particular structure
Having significant detail of cell structure only
C349S149000, C349S151000, C349S152000
Reexamination Certificate
active
06760090
ABSTRACT:
The present invention claims the benefit of Korean Patent Application No. P2001-62422 filed in Korea on Oct. 10, 2001, which is hereby incorporated by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a liquid crystal display device and a method of making a liquid crystal display device, and more particularly to a liquid crystal display device that prevents an electrical short circuit between electrodes that are formed on a tape carrier package.
2. Discussion of the Related Art
In general, a liquid crystal display (LCD) device of an active matrix driving system uses thin film transistors (TFT's) as switching devices to display image data as natural moving pictures. Such an LCD is commonly used for a monitor of a portable television or a laptop personal computer, for example, because of its small size as compared to a Brown tube device.
The active matrix liquid crystal display (LCD) device displays an image corresponding to a video signal on a pixel matrix (or picture element matrix) having pixels arranged at each intersections between gate lines and data lines. Each pixel includes a liquid crystal cell for controlling a quantity of light transmitted in accordance with a data signal voltage level transmitted along a data line. At least one of the TFT's is disposed at the intersection between the gate line and the data line in order to supply the data signal voltage level to the liquid crystal cell in response to a scanning signal that is transmitted along the gate line. Accordingly, such a liquid crystal display (LCD) requires a plurality of Driving Integrated Circuits (D-IC) for supplying data signals and scanning signals to the data and gate lines, respectively. The D-IC's are installed between a Printed Circuit Board (PCB) and a liquid crystal panel. The D-IC's respond to control signals received from the PCB, and supplies the data signals and the scanning signals to the data lines and the gate lines of the liquid crystal panel. Tape Automated Bonding (TAB) is a common method used for mounting the D-IC's where an effective area of the liquid crystal panel may be increased, thereby simplifying the mounting process of the D-IC's.
FIG. 1
is a cross sectional view showing a liquid crystal display device according to the conventional art. In
FIG. 1
, the liquid crystal display device includes a tape carrier package (TCP)
18
interconnected between a liquid crystal panel
11
and a PCB
24
, a D-IC (not shown) is mounted on the TCP
18
by a TAP method, and an anisotropic conductive film (ACF)
20
that attaches the TCP
18
onto the liquid crystal panel
11
.
The liquid crystal panel
11
includes an upper substrate
10
upon which a Color Filter Array (not shown) and an alignment film (not shown) are sequentially formed, a lower substrate
12
on which a TFT array (not shown) and an alignment film (not shown) are sequentially formed, and polarizing plates
14
and
16
sandwiching the upper substrate
10
and the lower substrate
12
. The lower substrate
12
of the liquid crystal panel
11
is attached to the TCP
18
by the ACF
20
under high temperature and high pressure, and is connected to the PCB
24
.
The D-IC (not shown) generates a driving signal in accordance with the control signal received from the PCB
24
. An electrode lead portion
26
of the TCP
18
is formed on a rear surface of the TCP
18
, and supplies the driving signal generated by the D-IC to the liquid crystal panel
11
. The PCB
24
is electrically connected to the liquid crystal panel
11
by an electrode lead portion
26
. One end region of the electrode lead portion
26
attached to the ACF
20
on a pad portion of the lower substrate
12
, and a second end region of the electrode lead portion
26
is soldered to the POB
24
. A solder resist
28
is formed on the electrode lead portion
26
for protection.
FIGS. 2A
to
2
C show a process for fabricating a liquid crystal display device according to the conventional art. In
FIG. 2A
, liquid crystal material is injected between the upper substrate
10
and the lower substrate
12
, and the upper substrate and the lower substrate are attached together. Then, polarizing plates
14
and
16
are attached to outside surfaces of the upper substrate
10
and the lower substrate
12
, thereby completing the liquid crystal display device. In addition, edge portions of the lower substrate
12
are ground in order to prevent any damaged during a grinding process.
In
FIG. 2B
, the ACF
20
is formed upon the lower substrate
12
of the liquid crystal panel
11
.
In
FIG. 2C
, the TCP
18
is formed upon the ACF
20
. The electrode lead portion
26
is electrically interconnected between the liquid crystal panel
11
with the PCB (
24
in
FIG. 1
) on the rear surface of the TCP
18
. Then, the solder resist
28
is formed at one end region of the electrode lead portion
26
. The solder resist
28
protects exposed regions of the electrode lead portion
26
formed at one side region of the rear surface of the TCP
18
. Accordingly, since the solder resist
28
is only formed in a region of the electrode lead portion
26
, an exposed area is created between the lower substrate
12
and the PCB
24
(in FIG.
1
).
FIG. 3
is a photograph showing an electrode lead portion of a tape carrier package shown in
FIG. 1
according to the conventional art. In
FIG. 3
, the exposed area created between the lower substrate
12
and the PCB
24
(in
FIG. 1
) is shown between the solder resist (S/R)
28
area and an adhesion area of the ACF
20
. Accordingly, when attaching the liquid crystal panel
11
to a top case (not shown) using a screw fastener, any metal impurities generated as a result of boring a pilot hole for the screw fastener in top case contaminate the exposed electrode lead portion
26
. Therefore, each electrode may electrically short circuit because of the contaminating metal impurities.
SUMMARY OF THE INVENTION
Accordingly, the present invention is directed to a liquid crystal display device and a method of making a liquid crystal display device that substantially obviates one or more of the problems due to limitations and disadvantages of the related art.
An object of the present invention is to provide a liquid crystal display that prevents an electrical short circuit between electrodes formed on a tape carrier package.
Additional features and advantages of the invention will be set forth in the description which follows, and in part will be apparent from the description, or may be learned by practice of the invention. The objective and other advantages of the invention will be realized and attained by the structure particularly pointed out in the written description hereof as well as the appended drawings.
To achieve these and other advantages and in accordance with the purposes of the present invention, as embodied and broadly described, a liquid crystal display a liquid crystal display includes a liquid crystal panel having a plurality of pads, a printed circuit board, a tape carrier package electrically interconnecting the liquid crystal panel and the printed circuit board, an electrode lead portion formed on a rear surface of the tape carrier package, an anisotropic conductive film connected to at least one of the plurality of pads of the liquid crystal panel and formed at a first side of the electrode lead portion, and a solder resist formed at a second side of the electrode lead portion and contacting the anisotropic conductive film.
In another aspect, a method for fabricating a liquid crystal display includes interconnecting a liquid crystal panel and a printed circuit board via a tape carrier package, forming an anisotropic conductive film on at least one of a plurality of pads of the liquid crystal panel and at a first side of an electrode lead portion formed on a rear surface of the tape carrier package, and forming a solder resist at a second side of the electrode lead portion to contact the anisotropic conductive film.
It is to be understood that both the fo
Chowdhury Tarifur R.
LG. Philips LCD Co. Ltd.
Morgan & Lewis & Bockius, LLP
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