Electric lamp and discharge devices – With gas or vapor – Three or more electrode discharge device
Reexamination Certificate
2000-03-20
2003-07-22
Patel, Ashok (Department: 2879)
Electric lamp and discharge devices
With gas or vapor
Three or more electrode discharge device
C313S048000, C345S205000
Reexamination Certificate
active
06597113
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a flat panel display such as a plasma display panel (abbreviated to “PDP”), and more specifically to a flat panel display having an improved structure for mounting on a panel a driver IC (integrated circuit) for driving display cells.
A PDP is generally constituted of a front transparent plate (glass plate) and a rear transparent plate (glass plate) bonded to each other to interpose therebetween a partition for confining a number of display cells, a rare gas being sealed within a display cell space confined by the partition and the front and rear transparent plates. On the front glass plate, a number of transparent scan electrodes and transparent sustain electrodes are located in parallel to one another, and on the rear glass plate, a number of data electrodes are located in parallel to one another, orthogonally to the scan electrodes and the sustain electrodes. By applying respective predetermined voltages to these three kinds of cell electrodes at predetermined timings, an electric discharge is generated between the electrodes, so that ultraviolet is generated by the electric discharge, with the result that a phosphor coated in the display cells generates a visible light in response to the generated ultraviolet. In a color display, different phosphors for respectively generating three primary colors of red, green and blue, are used in different display cells, so that the display cells are selectively driven for light generation, with the result that a desired color image can displayed.
As mentioned above, in order to cause the PDP to emit light from the respective display cells, it is necessary to supply the voltages to the respective electrodes at predetermined timings. For this purpose, a driver IC is required to be integrally mounted in the PDP.
Referring to
FIG. 8
, there is shown a partially broken, diagrammatic perspective view of a PDP apparatus
200
including a PDP module
1
having driver ICs mounted thereon. A PDP
10
included in the PDP module
1
, has a front glass plate
11
and a rear glass plate
12
bonded to each other, as mentioned above. A reinforcement plate
14
formed of for example aluminum is integrally mounted to a rear surface of the PDP
10
. This reinforcement plate
14
mechanically reinforces the PDP
10
, and also can be used as a mounting plate when the PDP module
1
is mounted within a casing
201
, in order to constitute the PDP apparatus
200
.
A display window
202
is formed in a front face of the casing
201
, and a protection plate
203
formed of for example a transparent acrylic resin, is mounted on the display window. The driver ICs mounted on the PDP
10
are located at a periphery of the PDP
10
, in such a manner that scan side driver ICs
3
connected to the scan electrodes and the sustain electrodes are mounted on one lateral side of the PDP
10
, and data side driver ICs
2
connected to the data electrodes are mounted on an upper or a lower side of the PDP
10
. These drivers ICs
2
and
3
are connected through a connector
204
fitted thereto to a not-shown control circuit and power supply, so that the drivers ICs
2
and
3
apply voltages supplied from the control circuit and power supply, to the respective electrodes.
Referring to
FIG. 9A
, there is shown a partial sectional view illustrating one example of a prior art mounting structure for mounting the data side driver IC
2
on the PDP
10
, which is disclosed by Japanese Patent Application Pre-examination Publication No. JP-A-10-260641. In this mounting structure, the data side driver IC
2
is constructed in the form of an IC package called a COF (chip on film), in which electrodes of an IC chip
40
are directly connected to an FPC (flexible printed circuit)
41
, and a region including the:electrodes of the IC chip
40
is encapsulated with a resin
42
. A back surface of the IC chip
40
is fixed by a heat conductive bonding agent
43
to a front face of an extension
14
a
of an aluminum reinforcement plate
14
, outwardly projected from a periphery of the PDP
10
for protecting the glass plates
11
and
12
of the PDP
10
. One end of the FPC
41
in the driver IC
2
is connected to a terminal
106
a
of the data electrodes formed on a front surface of the rear glass plate
12
, and the other end of the FPC
41
is connected to an input printed circuit board
18
which is integrally-provided on a periphery of a front surface of the aluminum reinforcement plate
14
. Incidentally, the reference number
19
designates a spacer inserted between the rear glass plate
12
and the aluminum reinforcement plate
14
.
In addition, the above referred patent publication discloses another mounting structure shown in
FIG. 9B
, in which the IC chip
40
of the driver IC of the COF structure is mounted on a rear surface of the aluminum reinforcement plate
14
. The FPC
41
is bent to extend over the peripheral edge of the aluminum reinforcement plate
14
so as to reach the rear surface of the periphery of the aluminum reinforcement plate
14
, as shown in
FIG. 9B. A
front side end of the FPC
41
is connected to the terminal
106
a
of the data electrode formed on the front surface of the rear glass plate
12
, and a rear side end of the FPC
41
is connected to the input printed circuit board
18
which is integrally provided on a rear surface of the aluminum reinforcement plate
14
.
The above mentioned prior art mounting structures can be said to have been designed to pay importance to heat dissipation of the IC chip
40
. Namely, as described in the above referred patent publication, in the color PDP, the heat generation of the driver IC
2
becomes remarkable because a load of the driver IC
2
increases with microminiaturization and the high density of the display cells. Therefore, it has become important to elevate the heat dissipation of the driver IC
2
. By mounting the driver IC on the aluminum reinforcement plate
14
to cause the heat generated in the IC chip
40
to be immediately transferred to the aluminum reinforcement plate
14
and to be dissipated from a surface of the aluminum reinforcement plate
14
, the above mentioned prior art mounting structure is intended to elevate the heat dissipation. On the other hand, in the prior art mounting structure shown in
FIG. 9B
proposed in the above referred patent publication for downsizing the PDP, by mounting the IC chip
40
on the rear surface of the aluminum reinforcement plate
14
, it becomes unnecessary to extend the periphery of the aluminum reinforcement plate
14
outwardly from the periphery of the PDP
10
, with the result that an outer scale of the PDP module is reduced.
The above mentioned mounting structures, however, since the IC chip
40
formed of a semiconductor such as silicon is directly fixed to the aluminum reinforcement plate
14
having a thermal expansion coefficient which is different from that of the semiconductor by one or more order of magnitude, when the driver IC
2
operates, a large heat stress acts on the IC chip
40
because of difference in heat expansion between the IC chip
40
and the aluminum reinforcement plate
14
caused by the heat generated in the IC chip
40
, with the result that a crack occurs in the IC chip
40
, so that reliability of the driver IC
2
lowers, and therefore, reliability of the PDP module
1
drops.
In the above mentioned mounting structures, furthermore, it is inevitable that the size of the PFC
41
in the COF structure, particularly, the length in a signal transmission direction from a signal input side to the terminal of the data electrode becomes long. Namely, in the mounting structure shown in
FIG. 9A
, since the IC chip
40
is fixed to the extension
14
a
of the aluminum reinforcement plate
14
extending outwardly from the periphery of the PDP
10
, the FPC
14
is bent in a thickness direction by a step difference corresponding to a thickness of the rear glass plate
12
, from the front surface of the rear glass plate
12
on which the terminals
106
of the data
NEC Corporation
Patel Ashok
Sughrue & Mion, PLLC
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