Liquid crystal cells – elements and systems – Particular structure – Having significant detail of cell structure only
Reexamination Certificate
1998-03-25
2001-08-21
Ton, Toan (Department: 2871)
Liquid crystal cells, elements and systems
Particular structure
Having significant detail of cell structure only
C349S149000, C349S152000
Reexamination Certificate
active
06278509
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a display device such as a liquid crystal display device used for information apparatus, home electrical appliances, and the like.
2. Description of the Related Art
With a recent growth of an information-oriented society, liquid crystal display devices have attracted increasing attention as display devices to be incorporated in information apparatus and home electrical appliances. This is because liquid crystal display devices are advantageous in that they are thin, light in weight, and operable with low power consumption.
FIG. 7
shows a conventional liquid crystal display device, and
FIG. 8
shows a sectional view taken along line C-C′ of FIG.
7
. The illustrated conventional liquid crystal device includes a liquid crystal panel
1
and a circuit board provided at the periphery of the liquid crystal panel
1
for driving pixels. The liquid crystal panel
1
includes a pair of substrates
1
a
and
1
b
each having an electrode and a liquid crystal layer interposed between the pair of substrates
1
a
and
1
b
. The circuit board includes a plurality of tape carrier packages (TCPs)
12
arranged in parallel, each of which includes an integrated circuit (IC)
3
for driving lines and pixels mounted on a flexible base. An output terminal group of each TCP is connected with the liquid crystal panel
1
via an anisotropic conductive film (ACF)
7
, while an input terminal group thereof is connected with a printed board
4
via an ACF or a solder
8
. The liquid crystal panel
1
is fixed to a chassis
5
with ribs
6
a
provided at the four corners of the liquid crystal panel
1
.
In order to realize further enhanced image quality and fineness for the liquid crystal display devices, the demand for reductions in pixel size has all the more increased. As the size of the pixels is reduced, the pixel pitch also needs to be smaller. This makes it extremely difficult to connect the liquid crystal panel
1
with the circuit board (i.e., the TCPs and the like) disposed at the periphery of the liquid crystal panel
1
. More specifically, as the pixel pitch of the liquid crystal panel
1
becomes smaller, the area of pixels which can be driven by one IC
3
becomes smaller, and thus the width of the input terminal group of the TCP
12
which includes the IC
3
is smaller. As the width of the input terminal group of the TCP
12
is smaller, the area of the TCP
12
which is in contact with the ACF or solder
8
is smaller. This makes it difficult to connect the TCP
12
with the printed board
4
.
In order to overcome the above problem, Japanese Laid-Open Publication No. 5-173166 discloses a liquid crystal display device as shown in FIG.
9
. In this conventional liquid crystal display device, the width of the input terminal side of each of TCPs
30
a
and
30
b
is different from the width of the output terminal side thereof. Moreover, the input terminal sides of the adjacent TCPs
30
a
and
30
b
are alternately shifted from each other, forming a zig-zag array. In this way, the width of the input terminal groups of the TCPs
30
a
and
30
b
can be made large compared with the width of the TCPs
12
of the uniform shape arranged in a line as shown in FIG.
7
. This facilitates the connection of the TCPs
30
a
and
30
b
with the printed board
4
via the ACF or solder
8
.
However, the conventional liquid crystal display device disclosed in the above-mentioned Japanese Laid-Open Publication No. 5-173166 has the following problem. Since two or more different shapes of TCPs are used, the process for connecting the TCPs is extremely complicated and troublesome. Two or more types of molds are also required to form these different shapes of TCPs.
In view of the foregoing, the objective of the present invention is to provide a display device where the connection between the input terminal group of the TCP and the printed circuit board is prevented from being easily disconnected and thus warping of a display panel is prevented.
SUMMARY OF THE INVENTION
The display device of this invention includes: a display panel; a printed circuit board; a plurality of tape carrier packages each having a first side, a second side, an output terminal group located near the first side, and an input terminal group located near the second side; and a chassis having a plurality of ribs for fixing the display panel, wherein the output terminal group of each of the plurality of tape carrier packages is connected with the display panel, the input terminal group of each of the plurality of tape carrier packages is connected with the printed circuit board, the first side of each of the plurality of tape carrier packages is shorter than the second side of each of the plurality of tape carrier packages, and at least one rib of the plurality of ribs is located between the plurality of tape carrier packages.
In one embodiment of the invention, a length of one of the plurality of ribs which is in contact with a side of the display panel opposing a side which is in contact with the at least one rib is larger than a length of the at least one rib.
In another embodiment of the invention, an electronic component is mounted on the printed circuit board, and the electronic component is located between the plurality of tape carrier packages.
In still another embodiment of the invention, the width of a portion of each of the plurality of tape carrier packages which overlaps the printed circuit board is smaller than the length of the second side so that a space for disposing an electronic component is secured.
In still another embodiment of the invention, the distance between the input terminal group of one of the plurality of tape carrier packages and the input terminal group of another one adjacent to the one of the plurality of tape carrier packages is shorter than the distance between the output terminal group of the one of the plurality of tape carrier packages and the output terminal group of the another one adjacent to the one of the plurality of tape carrier packages.
According to the present invention, the width of the output terminal side of each TCP which is connected with the substrate of the display panel is smaller than the width of the input terminal side thereof which is connected with the printed board. At least one rib for fixing the display panel is provided between the output terminal sides of the adjacent TCPs. This increases the strength for supporting the display panel and prevents the display panel from warping even if the size of the display screen is made large.
Since the width of the input terminal side of each TCP is larger than the width of the output terminal side thereof, the terminal pitch on the input terminal side can be increased. This increases the area of the TCP which is in contact with the ACF or solder, thereby facilitating the connection of the TCP with the printed board.
Since the width of the input terminal side of each TCP is large, the number of terminals on the input terminal side can be increased. This makes it possible to employ a signal input method called a two-port input method where the transfer frequency is halved and thus unnecessary radiation can be suppressed.
By arranging the TCPs in parallel so that the input terminal sides of the adjacent TCPs are close to each other, the width of the input terminal sides can be made large. This allows for a large terminal pitch or an increased number of terminals on the input terminal side
By forming a narrow portion of the TCP continuing from the output terminal side to an area of a predetermined range which overlies the printed board, spaces can be secured between the narrow portions of the adjacent TCPs on the printed board. Electronic components may be mounted at such spaces, thereby realizing effective use of otherwise unused spaces on the printed board.
Thus, the invention described herein makes possible the advantage of providing a display device where the connection between the input terminal group of the TCP and the printed circuit boa
Kawaguchi Hisao
Ohga Masaaki
Nixon & Vanderhye P.C.
Sharp Kabushiki Kaisha
Ton Toan
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