Liquid crystal cells – elements and systems – Particular structure – Having significant detail of cell structure only
Reexamination Certificate
2000-03-24
2003-01-14
Parker, Kenneth (Department: 2871)
Liquid crystal cells, elements and systems
Particular structure
Having significant detail of cell structure only
C349S150000, C349S151000, C349S152000
Reexamination Certificate
active
06507384
ABSTRACT:
BACKGROUND
1. Industrial Field of the Invention
The present invention relates to an electro-optical device, such as a liquid crystal device or an EL (electroluminescent) electro-optical device. The present invention also relates a flexible printed wiring board for use in the electro-optical device, and to electronic equipment including the electro-optical device.
2. Description of the Related Art
In recent years, electro-optical devices have been widely used as information display terminals in portable devices, homes, offices, factories, automobiles, and the like. In particular, liquid crystal display devices have characteristics of low profile, low weight, low voltage, and low power consumption. For this reason, liquid crystal devices are the dominant devices of electronic display both now and in the future, and are actively applied to PDA (Personal Digital Assistants) and the like by making use of the low power consumption.
As one example of conventional liquid crystal display devices,
FIG. 9
shows a passive-matrix-driven-type liquid crystal display device
1
. The liquid crystal display device
1
is basically composed of a liquid crystal display panel
2
and a printed board
3
. The liquid crystal display panel
2
and the printed board
3
are electrically connected via first and second flexible printed wiring boards
4
and
5
.
The liquid crystal display panel
2
has a pair of glass substrates
6
and
7
that are arranged to oppose each other. A sealing material (not shown) is provided between the glass substrates
6
and
7
so as to surround a display area. Liquid crystal is sealed in a gap formed by the glass substrates
6
and
7
and the sealing material. On a surface of the glass substrate
6
opposing the glass substrate
7
(opposing surface of the glass substrate
6
), a plurality of signal electrodes
8
are formed in parallel with each other. On the other hand, on a surface of the glass substrate
7
opposing the glass substrate
6
(opposing surface of the glass substrate
7
), a plurality of scanning electrodes
9
are formed in a direction perpendicular to the signal electrodes
8
.
At a predetermined side edge portion (lower side edge portion in
FIG. 9
) of the liquid crystal panel
2
, an edge of the glass substrate
6
is set to project sideways (downward in
FIG. 9
) from an edge of the glass substrate
7
. The projected area (area in which the glass substrate
6
does not overlap the glass substrate
7
) constitutes a wiring connection area
6
A. In addition, at a side edge portion (left side edge portion) of the liquid crystal display panel
2
adjacent to the above-described side edge portion, an edge of the glass substrate
7
is set to project sideways (leftward in
FIG. 9
) from the edge of the glass substrate
6
. The projected area (area in which the glass substrate
7
does not overlap the glass substrate
6
) constitutes a wiring connection area
7
A. Signal driver IC chips
10
and
11
are mounted by a COG (Chip on Glass)-technique on the wiring connection area
6
A of the glass substrate
6
. These signal driver IC chips
10
and
11
are connected to output terminals
8
A having a plurality of the extended signal electrodes
8
and to input terminals
12
formed on the edge of the wiring connection area
6
A. A scanning driver IC chip
13
is COG-mounted on the wiring connection area
7
A of the glass substrate
7
. The scanning driver IC chip
13
is connected to output terminals
9
A having a plurality of the extended scanning electrodes
9
and to input terminals
14
formed on the edge of the wiring connection area
7
A.
An output terminal area
4
A of the first flexible printed wiring board
4
is connected via an anisotropic conductive film (ACF) so as to be electrically connected to the plurality of input terminals
12
arranged along the long side of the wiring connection area
6
A of the glass substrate
6
. Similarly, an output terminal area
5
A of the second flexible printed wiring board
5
is connected via an anisotropic conductive film so as to be electrically connected to the plurality of input terminals
14
disposed along the long side of the wiring connection area
7
A of the glass substrate
7
.
An input terminal area
4
B of the first flexible printed wiring board
4
is connected to output terminals
15
formed on the printed board
3
via an anisotropic conductive film or a filter. An input terminal area
5
B of the second flexible printed wiring board
5
is connected to output terminals
16
formed on the printed board
3
via an anisotropic conductive film or a filter. The printed board
3
has a predetermined wiring formed thereon and various types of electronic parts mounted thereon. The input terminal area
4
B of the first flexible printed wiring board
4
and the input terminal area
5
B of the second flexible printed wiring board
5
are connected by different portions, which are offset from each other, of the printed board
3
.
As an example of the electronic equipment using the liquid crystal display device having the above-described construction, an electronic equipment includes an input unit, such as a keyboard or a 10-button keypad and displays data by a liquid crystal display panel according to input operation to the input unit. In such an electronic equipment, a liquid crystal display panel and a printed board are incorporated into a chassis (panel-accommodating frame). In this case, two flexible printed wiring boards are bent into the device so that the printed board is arranged at the back of the liquid crystal display panel.
In the above-described liquid crystal display device and the electronic equipment using the liquid crystal display device, however, a display area of the liquid crystal display panel may become small and visibility may be deteriorated when the weight and thickness of the device are reduced to pursue portability. In a portable information device, such as a mobile phone or a pocket size personal computer in which portability is very important, a width of a casing or a width of a frame outside the display area has been reduced to the limit.
As shown in
FIG. 10
, in the liquid crystal display
1
having the above-described construction, the wiring connection area
7
A exists in the lateral direction (left side in the figure), and the wiring connection area
7
A is required to secure a width x
1
for mounting the scanning driver IC chip
13
, a predetermined connection margin x
2
for connecting the output terminal area
5
A of the flexible printed wiring board
5
, and a size x
3
for separating the scanning driver IC chip
13
and the output terminal area
5
A of the flexible printed wiring board
5
. For this reason, there is a problem in that the ratio of the display area accounting for the entire surface of the liquid crystal display panel
2
decreases with a decrease in the width of the liquid crystal display panel
2
.
The problem caused by the wiring connection area in the liquid crystal display panel is not limited to a case where a liquid crystal display device or an electronic equipment using the liquid crystal display device is reduced in size. That is, even in an electronic equipment including a relatively large liquid crystal display device, it is demanded that a display area in a casing, such as a chassis, for accommodating the display device is enlarged to the fullest extent by reducing a width of a frame outside a display area of the liquid crystal display panel.
Furthermore, in the above-described liquid crystal display device
1
, it is necessary to independently join the flexible printed wiring board
4
, which is to be connected to a wiring connection area
6
A of the glass substrate
6
having the signal driver IC chips
10
and
11
mounted thereon, and the flexible printed wiring board, which is to be connected to the wiring connection area
7
A of the glass substrate
7
having the scanning driver IC chip
13
mounted thereon, to the surface and the back of the printed board
3
. For this reason, a modular process becomes complicated and lacks conv
Aruga Yasuhito
Endo Kogo
Oishi Eiji
Chung David
Harness & Dickey & Pierce P.L.C.
Parker Kenneth
Seiko Epson Corporation
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