Electricity: conductors and insulators – Conduits – cables or conductors – Preformed panel circuit arrangement
Reexamination Certificate
2002-03-25
2004-12-28
Zarneke, David (Department: 2827)
Electricity: conductors and insulators
Conduits, cables or conductors
Preformed panel circuit arrangement
C174S254000, C174S260000, C361S767000, C361S795000, C349S149000
Reexamination Certificate
active
06835896
ABSTRACT:
This application claims the benefit of Korean Patent Application No. 2001-15563, filed on Mar. 26, 2001 in Korea, 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 (LCD) device and more particularly, to a packaging structure of a driving circuit for a liquid crystal display device and a packaging method of the driving circuit for the liquid crystal display device.
2. Discussion of the Related Art
Flat panel display devices, that are thin, low weight and low power consumption, have been required as the information age rapidly evolves. The liquid crystal display device is widely used for notebook computers and desktop monitors, etc. because of its superior resolution, color image display and quality of displayed images.
Generally, the liquid crystal display device has upper and lower substrates, which are spaced apart and facing each other. Each of the substrates includes an electrode and the electrodes of each upper and lower substrate face each other. Liquid crystal is interposed between the upper substrate and the lower substrate. A voltage is applied to the liquid crystal through the electrodes of each substrate, and thus an alignment of the liquid crystal molecules is changed according the applied voltage to display images.
The liquid crystal display device mainly consists of a liquid crystal panel, which includes liquid crystal between the upper substrate and the lower substrate, a back light behind the liquid crystal panel and a driving unit in an outer side edge of the liquid crystal panel. The driving unit includes a driving circuit, i.e., a drive integrated circuit for applying signals to electric lines of the liquid crystal panel and the driving unit can be one of the following: a chip on glass (COG), a chip on film (COF) and a tape carrier package (TCP) depending on a packaging method of the drive integrated circuit to the liquid crystal panel. With a chip on glass (COG), the drive integrated circuit is packaged on an array substrate of the liquid crystal panel, a size of the liquid crystal panel increases. Whereas a compact structure can be obtained with a chip on film (COF) or the tape carrier package (TCP), because the drive integrated circuit is packaged using a film with the drive integrated circuit that can be bent toward a rear side of the liquid crystal panel. Accordingly, the chip on film (COF) or the tape carrier package (TCP) has been primarily used in the field. The chip on film (COF) or the tape carrier package (TCP) includes the film in which the drive integrated circuit is included.
FIG. 1
is a plan view illustrating a schematic structure of a typical liquid crystal display device that uses the chip on film (COF) or the tape carrier package (TCP). As shown in the figure, the liquid crystal panel
10
includes an array substrate
11
and a color filter substrate
12
and a liquid crystal layer (not shown) is interposed between the array substrate
11
and the color filter substrate
12
. Because the array substrate
11
is larger than the color filter substrate
12
, a portion of the array substrate
11
is not covered with the color filter substrate
12
, and a pad (not shown) is formed on an outer, marginal space of the array substrate
11
to receive a signal to the electric line of the liquid crystal panel
10
. The pad of the array substrate
11
is connected to the tape carrier package (TCP) (or the chip on film (COF))
30
and the tape carrier package. (TCP) (or the chip on film (COF))
30
includes the drive integrated circuit
31
for driving the liquid crystal panel
10
. The tape carrier package (TCP) (or the chip on film (COF))
30
is also connected to a printed circuit board (PCB)
20
. Alternatively, a back light (not shown) is positioned behind the liquid crystal panel
10
for a light source. The printed circuit board (PCB) is a board on which a plurality of elements such as an integrated circuit (IC) is formed and generates various control signals and data signals for driving the liquid crystal panel
10
.
An anisotropic conductive film (ACF) is used for connecting the tape carrier package (TCP) (or the chip on film (COF))
30
to the liquid crystal panel
10
or to the printed circuit board (PCB)
20
. The anisotropic conductive film (ACE) is a type of a thermosetting resin containing a number of conductive particles. The connecting method for the liquid crystal panel
10
and the tape carrier package (TCP) (or the chip on film (COF))
30
is as follows. First, the anisotropic conductive film (ACF) is pasted on the pad of the liquid crystal panel
10
and then the tape carrier package (TCP) (or the chip on film (COF))
30
is attached to the anisotropic conductive film (ACF) on the pad of the liquid crystal panel
10
. Finally, if the tape carrier package (TCP) is pressed to the anisotropic conductive film (ACF) using heat, the tape carrier package (TCP) and the anisotropic conductive film (ACE) are electrically connected each other. Next, it is desirable to apply the proper heat and pressure suited for material of the tape carrier package (TCP) and the anisotropic conductive film (ACF). The connecting method for the tape carrier package (TCP) (or the chip on film (COF))
30
and the printed circuit board (PCB)
20
can be performed with the same process as that of the tape carrier package (TCP)
30
and the liquid crystal panel
10
. Since the tape carrier package (TCP) and the chip on film (COF) use a film that is flexible, they are suitable for a compact structure. However, because a metal line thickness of the chip on film (COF) is thinner than a metal line thickness of the tape carrier package (TCP), the chip on film (COF) is suitable for patterning, and can have a finer structure than the tape carrier package (TCP).
A structure and a manufacturing process of the chip on film (COF) will be described hereinafter with reference to the figures. FIG.
2
A and
FIG. 2B
being plan views illustrating a structure of a conventional chip on film (COF).
FIG. 2A
illustrates the chip on film (COF) of a gate driving circuit for applying a voltage to a gate signal line of the liquid crystal panel.
FIG. 2B
illustrates the chip on film (COF) of a data driving circuit for applying a voltage to a data signal line of the liquid crystal panel. As shown in the figures, a plurality of input metal lines
60
and a plurality of output metal lines
70
are formed on a base film
50
, maintaining a certain distance between them. An overcoat layer
80
is formed on the input metal lines
60
and the output metal lines
70
. The overcoat layer
80
exposes terminals of the input metal lines
60
and the output metal lines
70
; the drive integrated circuit
90
is connected to the terminals at one end of the input metal lines
60
and the output metal lines
70
, respectively. Other terminals at the other end of the output metal lines
70
are connected to a gate pad (not shown) or a data pad (not shown) and other terminals at the other end of the input metal lines
60
are connected to the external printed circuit board (PCB). Each of the output metal lines
70
must correspond to each signal line of the liquid crystal panel. However, the number of input metal lines
60
only have to be sufficient to deliver a signal generated in the printed circuit board (PCB) to the drive integrated circuit
90
. Accordingly, fewer input metal lines
60
may be formed than the output metal lines
70
with a larger space between them than the output metal lines
70
.
FIGS. 3A
to
3
C are plan views illustrating a packaging process of a chip on film (COF) of a data driving circuit according to the related art. In
FIG. 3A
, a plurality of input metal lines
60
and a plurality of output metal lines
70
are formed by patterning a metal film on a base film
50
. Next, the input metal lines
60
and the output metal lines
70
are formed keeping a certain distance respectively between them. As described before, the inpu
Hwang Kwang-Jo
Kim Woo-Hyun
LG.Philips LCD Co. , Ltd.
McKenna Long & Aldridge LLP
Patel I B
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