Active solid-state devices (e.g. – transistors – solid-state diode – Lead frame – On insulating carrier other than a printed circuit board
Reexamination Certificate
2001-04-06
2004-01-13
Flynn, Nathan J. (Department: 2826)
Active solid-state devices (e.g., transistors, solid-state diode
Lead frame
On insulating carrier other than a printed circuit board
C349S058000, C349S150000
Reexamination Certificate
active
06677664
ABSTRACT:
BACKGROUND OF THE INVENTION
(1) Field of the Invention
This invention relates to a display driver module and its mounting structure and, more particularly, to a display driver module having a driver integrated circuit for driving a large-screen flat panel display, such as a plasma display, and a wiring board on which this driver integrated circuit is mounted and being suitable for fixing this driver integrated circuit on a metal chassis on the flat panel display to radiate heat and a mounting structure for a portion where such a display driver module is mounted on a plasma display panel.
(2) Description of the Related Art
Attention is riveted to a large-screen flat panel display with a plasma display panel on it as the likeliest candidate for a next-generation large-size television because of its small depth, wide view angle, and easiness of making a large screen. These are the merits of an ordinary flat display.
This plasma display has a large number of driver integrated circuits for leading display signals to a plasma display panel and is controlled and driven by a display driver module which received control signals from a control board. This is the same with a display device using a liquid crystal panel, being a flat display.
FIGS. 10 and 11
show the structure of such a conventional display driver module.
FIG. 10
is a perspective view showing an example of a conventional display driver module.
FIG. 11
is a cross-sectional view of a feature of a conventional display driver module.
A conventional display driver module with integrated circuit chips, which generate much heat, on it uses a flexible wiring board
101
with a wiring pattern (not shown) formed on its top, to the bottom of which an aluminum plate
102
for radiating heat is attached.
A hole
103
is made at an integrated circuit chip mounting portion (die bonding portion) in the flexible wiring board
101
. An integrated circuit chip
104
for a driver is attached through the hole
103
directly to the aluminum plate
102
for radiating heat by the use of an adhesive
105
. An electrode on the integrated circuit chip
104
and a copper pattern for wiring on the flexible wiring board
101
are connected with a gold wire
106
by wire bonding, and then the integrated circuit chip
104
is coated with resin
107
.
An input electrode portion
108
for connecting to a control board is formed at one end of the flexible wiring board
101
and an output electrode portion
109
for connecting to a plasma display panel is formed at the opposite end.
A display driver module having such a structure uses the flexible wiring board
101
with the aluminum plate
102
for radiating heat attached to it. This structure results in a high cost. Therefore, it is suggested that a metal chassis on a display should be used as a radiator for the integrated circuit chip
104
.
Furthermore, the integrated circuit chip
104
for a driver and a wiring pattern on the flexible wiring board
101
are connected by wires which are stretched one by one with a wire bonder. With an increase in production, however, the productivity of such wire bonding is becoming an issue, as with liquid crystal panels ahead of plasma display panels. That is to say, if there are a large number of terminals on which wire bonding must be performed, a wire bonding process will take much time. Furthermore, many wire bonders are necessary for mass production, resulting in a high equipment investment cost. Therefore, flip chip bonding suitable for mass production is attempted.
In some examples of the flip chip connection, an anisotropic conductive resin is used as the most economical structure. It is discussed in Japanese Patent Laid-Open Publication No.Hei9-244047, Japanese Patent Laid-Open Publication No.Hei9-146110, Japanese Patent Laid-Open Publication No.Hei7-211423, etc., in which it is used primarily for a liquid crystal panel. It is also applied to a printed circuit board, of course. Japanese Patent Laid-Open Publication No.Hei11-67832 discloses such an example.
FIGS.
12
(A) and (B) are fragmentary cross-sectional views showing a schematic of a mounting structure for a conventional display driver module. FIG.
12
(A) is a fragmentary cross-sectional view of its feature. FIG.
12
(B) is an enlarged cross-sectional view of its integrated circuit mounted portion.
With a plasma display panel, an X-side sustain circuit board for controlling and driving an X electrode on its front panel, a Y-side sustain circuit board for controlling and driving a Y electrode on its front panel, and a logic circuit board for controlling and driving an address (A) electrode on its back panel are signal processing circuits connected to it. The X-side sustain circuit board is connected to the plasma display panel via a flexible wiring board. Each of the Y-side sustain circuit board and the logic circuit board is connected to the plasma display panel via a display driver module, being a flexible wiring board with a driver integrated circuit mounted on it. Connections formed by these display driver modules and the plasma display panel have the same structure. In addition, connections formed by these display driver modules and the signal processing circuits also have the same structure. In
FIG. 12
, therefore, an address driver module which connects the logic circuit board and the A electrode is shown as an example.
A plasma display panel consists of a front panel
111
and aback panel
112
, which are supported with an aluminum chassis
114
via an adhesive sheet
113
. An address bus board
115
for connecting the aluminum chassis
114
and a logic circuit board is placed on the aluminum chassis
114
. A connector
116
is placed on the address bus board
115
.
An address driver module consists of an address integrated circuit
117
and a flexible wiring board
118
. One wiring end of the flexible wiring board
118
is connected to the address bus board
115
by the connector
116
and the other wiring end of the flexible wiring board
118
is connected to an A electrode on the back panel
112
by an anisotropic conductive film (ACF)
119
into which conductive particles are mixed.
The address integrated circuit
117
is connected to the flexible wiring board
118
by the eutectic soldering of gold bumps
120
formed on a circuit-formed surface of the address integrated circuit
117
and tin (not shown) on copper wiring formed on the flexible wiring board
118
. A portion around the connection is filled with an underfiller
121
.
As stated above, in a conventional mounting structure for a display driver module, the flexible wiring board
118
and the plasma display panel are connected by the anisotropic conductive film
119
and the flexible wiring board
118
and the signal processing circuit are connected by the connector
116
. An ampere-level powerful electric current which runs through a power-supply terminal of the address integrated circuit
117
must be handled. Furthermore, the address integrated circuit
117
must be replaced when it fails. If these things are taken into consideration, it is rational to use the connector
116
.
Even in a conventional display driver module in which bonding time is taken into consideration, however, an integrated circuit chip with bump electrodes on it is facedown-bonded to a flexible wiring board and a joint formed by them is solidified with an underfiller. The process for connected them therefore takes much time.
Furthermore, in a mounting structure especially for a conventional scan or address display driver module, a connection at gold bumps formed by a driver integrated circuit and a flexible wiring board, in the display driver module, is filled with an underfiller, an anisotropic conductive film is used at a connection formed by the display driver module and a plasma display panel, and a connector is used at a connection formed by the display driver module and a signal processing circuit. That is to say, these three connections differ in mounting structure. This results in a complex structure and an increase in the number of the types of
Hirohashi Osamu
Inoue Hirokazu
Kawada Toyoshi
Ohsawa Michitaka
Sano Yuji
Andujar Leonardo
Flynn Nathan J.
Fujitsu Hitachi Plasma Display Limited
Staas & Halsey , LLP
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