Liquid crystal cells – elements and systems – Particular structure – Having significant detail of cell structure only
Reexamination Certificate
1998-07-09
2001-09-18
Malinowski, Walter J. (Department: 2164)
Liquid crystal cells, elements and systems
Particular structure
Having significant detail of cell structure only
C349S150000, C349S151000
Reexamination Certificate
active
06292248
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a liquid crystal display apparatus, and more particularly, to a liquid crystal panel incorporating a “chips-on-glass” (COG) system wherein integrated circuit (IC) chips are directly mounted on a glass substrate. Also, the present invention is directed to a method of manufacturing a COG type liquid crystal panel.
2. Description of the Related Art
Since a liquid crystal display apparatus display has advantages including a light weight, a small thickness, a low power consumption and so on, its applications have been steadily enlarged. The liquid crystal display apparatus includes a picture display having picture elements or pixels of liquid crystal arranged in a matrix pattern, and driving IC chips, hereinafter referred to as D-IC chips, for driving the liquid crystal display. Recently, a liquid crystal display apparatus has been manufactured using the COG system in which D-IC chips are directly mounted on the edge of a glass substrate. Also, the COG type liquid crystal panel makes use of a flexible printed circuit (FPC) film for applying signals to the D-IC chips.
In such a COG type liquid crystal panel, since the D-IC chips and the FPC film are mounted at different positions on the glass substrate, the effective field area is small and the size of liquid crystal panel is large. Further, the FPC film includes a wiring for commonly applying electric signals to all the D-IC chips. This results in an increase in the wiring amount of the FPC film, as well as an increase in the manufacturing cost of FPC film and an increase in the manufacturing cost of liquid crystal panel.
For example, as shown in FIG.
1
A and
FIG. 1B
, the COG type liquid crystal panel includes D-IC chips
6
mounted on the edge of a lower glass substrate
4
in such a manner to be positioned between an upper glass substrate
2
and a FPC film
8
. A picture display having liquid crystal cells and thin film transistors (TFTs) arranged in a matrix pattern is formed between the lower glass substrate
4
and the upper glass substrate
2
. The edge of the lower glass substrate
4
mounted with the D-IC chips
6
and the FPC film
8
is usually referred to as a “pad area” because electrode pads for supplying signals to drive the TFTs are located at the edge of the lower glass substrate
4
. In this pad area, output wiring electrodes (not shown) are provided for connecting the D-IC chips
6
with the picture display and input wiring electrodes (not shown) are provided for connecting the D-IC chips
6
and the FPC film. The D-IC chips
6
are provided to drive the TFTs and are adhered to the pad area via an anisotropic conductive film (ACF)
10
and bumps
10
A in such a manner to be electrically connected to the input and output wiring electrodes. The FPC film
8
is mounted with a wiring for transferring electrical signals, e.g., video data signals, timing control signals and voltage signals, from a control circuit (not shown) to the D-IC chips
6
. Such a FPC film
8
also is adhered to the pad area via the ACF
10
and the bumps l
0
A in such a manner to be electrically connected to the input wiring electrodes.
As described above, in the conventional COG type liquid crystal panel, the D-IC chips and the FPC film are mounted in parallel at the pad area, causing the pad area to be enlarged. As a result of this mounting arrangement, the field area becomes small and the size of glass substrate becomes large. Further, in the conventional COG type liquid crystal panel, the FPC film is adhered to the pad area on the lower glass substrate such that it is located at positions corresponding to locations of all of the D-IC chips. This results in an increase in a wiring amount located at the FPC film and an increase in the manufacturing cost of the FPC film and a increase in the manufacturing cost of the liquid crystal panel.
SUMMARY OF THE INVENTION
In order to overcome the problems described above, preferred embodiments of the present invention provide a COG type liquid crystal panel that is adapted to enlarge a field area and to reduce the size of a glass substrate, and a method for such a COG type liquid crystal panel.
In addition, the preferred embodiments of the present invention provide a COG type liquid crystal panel that is adapted to simplify a FPC film, and a method for making such a COG type liquid crystal panel with a simplified FPC.
According to one aspect of preferred embodiments of the present invention, a liquid crystal panel incorporating a chips-on-glass (COG) system and having a plurality of pixels arranged between an upper glass substrate and a lower glass substrate, and electrode pads connected to the pixels on the lower glass substrate, including driving integrated circuit chips mounted on the lower glass substrate to apply signals to the electrode pads, and a flexible printed circuit film mounted on the lower glass substrate to overlap the driving integrated circuit chips for applying electrical signals to the driving integrated circuit chips.
According to another preferred embodiment of the present invention, a liquid crystal panel incorporating a COG system and having a plurality of pixels arranged between an upper glass substrate and a lower glass substrate includes first electrode pads connected to the pixels on the lower glass substrate and second electrode pads located on the lower glass substrate and substantially parallel to the first electrode pads, including a signal wiring disposed on the lower glass substrate to intersect the second electrode pads and to be coupled to a portion of the second electrode pads, a plurality of driving integrated circuit chips mounted on the lower glass substrate so as to be electrically coupled to the first and second electrode pads, and a flexible printed circuit film mounted on the lower glass substrate so as to be electrically coupled to the signal wiring and the remaining second electrode pads, for applying electrical signals to the driving integrated circuit chips.
According to still another aspect of preferred embodiments the present invention, there is provided with a liquid crystal panel of COG system having a plurality of pixels arranged between an upper glass substrate and a lower glass substrate, first electrode pads connected to the pixels on the lower glass substrate, and second electrode pads on the lower glass substrate and substantially parallel to the first electrode pads, including a signal wiring located on the lower glass substrate to intersect the second electrode pads and to be coupled to a part of the second electrode pads, a plurality of driving integrated circuit chips mounted on the lower glass substrate to be electrically coupled to the first and second electrode pads, a first flexible printed circuit film mounted on the lower glass substrate to be electrically coupled to the signal wiring for applying first electrical signals to the driving integrated circuit chips, and a second flexible printed circuit film mounted at the upper portion of the driving integrated circuit chips to apply second electrical signals to the driving integrated circuit chips.
According to still another preferred embodiment of the present invention, a method of manufacturing a liquid crystal panel incorporating a COG system and including the steps of preparing a glass substrate having a plurality of pixels and electrode pads formed thereon, the electrode pads being connected to the pixels, adhering a first anisotropic conductive film to the upper portions of the electrode pads, arranging first conductive bumps on the first anisotropic conductive film to correspond to positions of the electrode pads, disposing a flexible printed circuit film at the upper portions of the first conductive bumps, pressing the flexible printed circuit film, adhering a second anisotropic conductive film to the upper portion of the flexible printed circuit film, arranging second conductive bumps along both edges of the second anisotropic conductive film, arranging driving integrated circuit chips at
Kim Jin Kyu
Lee Joo Hong
LG. Philips LCD Co. Ltd.
Malinowski Walter J.
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