Active solid-state devices (e.g. – transistors – solid-state diode – Housing or package
Reexamination Certificate
1999-08-19
2001-02-20
Abraham, Fetsum (Department: 2811)
Active solid-state devices (e.g., transistors, solid-state diode
Housing or package
C257S700000, C257S668000, C257S785000
Reexamination Certificate
active
06191471
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to a tape carrier package (TCP) which supports an integrated circuit and transmits a signal between a section external to the tape carrier package and the integrated circuit, particularly concerns a tape carrier package which supports a liquid crystal driver integrated circuit (IC) chip for driving a liquid crystal panel disposed in a liquid crystal display device, and which transmits a signal among the liquid crystal driver IC, the liquid crystal panel, and the section external to the TCP.
BACKGROUND OF THE INVENTION
Conventionally, in many cases, a liquid crystal driver IC chip for driving a liquid crystal panel has been installed in the liquid crystal panel as a tape carrier package, which is one of the packages for a semiconductor device. Such a liquid crystal driver IC is installed, for example, in a liquid crystal panel module shown in FIG.
22
.
As shown in
FIG. 22
, a liquid crystal panel
70
is provided with a plurality of tape carrier packages
72
, each having a liquid crystal driver IC chip
71
. Each tape carrier package
72
includes outer leads (not shown) connected to output terminals and the liquid crystal driver IC chip
71
respectively. The liquid crystal driver IC chip IC
71
is connected with the liquid crystal panel
70
via the outer leads for the output terminals and is connected with a flexible substrate
73
via the outer leads for the input terminals. A signal is transmitted and power is supplied to each of the liquid crystal driver IC chips
71
via wires disposed on the flexible substrate
73
.
In recent years, because of a growing need for more compact and lightweight products in the marketplace, it has been necessary to develop a smaller version of a semiconductor device disposed in a liquid crystal panel. In order to meet such a demand, Japanese Unexamined Patent Publication No. 3684/1994(Tokukaihei
6-3684
, published on Jan. 14, 1994) discloses a liquid crystal driver IC tape carrier package.
FIG. 23
shows a construction of the liquid crystal driver IC tape carrier package disclosed in the above publication.
The above-mentioned liquid crystal driver IC tape carrier package is provided with a liquid crystal driver IC chip
117
at the center, input/output signal terminals
111
and
112
which are bilaterally symmetrical, and a liquid crystal drive output terminal
115
at the center. This construction supplies electricity and transmits various signals (for example, controlling signals such as a clock, a start signal, and a synchronizing signal) by using wires in the liquid crystal driver IC chip
117
. With this arrangement, it is not necessary to provide a flexible substrate for supplying power and transmitting various signals.
Generally, it has been required that such a liquid crystal panel module be still more compact and lightweight at lower cost.
However, in the construction which supplies power and transmits various signals by using the wires of the liquid crystal driver IC chip
117
, when a number of tape carrier packages are connected, a voltage drop may occur especially on power supplying wires due to an increase in the number of connected tape carrier packages, resulting in degradation in display quality of the liquid crystal panel.
Here, the power supplying wires, which use the wires of the liquid crystal driver IC chip
117
, are, for example, those connected to liquid crystal driving power source.
Voltage from the liquid crystal driving power source causes a voltage drop due to resistance on the wires of the liquid crystal driver IC chip
117
, and proper driving conditions are not satisfied, resulting in degradation in display quality of the liquid crystal panel. Further, voltage from a logic driving power source is also supplied by using the wires inside the chip; thus, again, a voltage drop may cause an adverse effect on a logic operation. Generally, a liquid crystal panel is normally driven by connecting a number of liquid crystal driver IC chips to the liquid crystal panel, and the greater is the number of LCD IC chips connected, the more serious is the described problem of voltage drop.
SUMMARY OF THE INVENTION
An objective of the present invention is to provide a tape carrier package which can prevent a voltage drop caused by wire resistance.
In order to achieve the objective, the tape carrier package of the present invention, that supports an integrated circuit and transmits a signal between a section external to the tape carrier package and the integrated circuit, including: a tape substrate having a first region and a second region on one of the surfaces thereof, a plurality of leads which are formed in the first region and transmit a signal between the section external to the tape carrier package and the integrated circuit, and signal transmitting wires which are formed in the second region and transmit a signal among a plurality of the leads, is characterized in that the tape substrate can be folded into 180 degrees along a boundary so as to allow the first region and the second region to oppose each other, and a plurality of the leads are electrically connected to the signal transmitting wires in a state in which the tape substrate is folded.
With this arrangement, when the tape substrate is folded into 180 degrees so as to overlay the leads onto the signal transmitting wires, along a boundary serving as a fold between the first region in which a plurality of the leads are formed and the second region in which the signal transmitting wires are formed, it is possible to electrically connect the leads to the signal transmitting wires by soldering, etc. This arrangement makes it possible to transmit input signals and supply power among a plurality of the leads by using mainly the signal transmitting wires disposed on the tape carrier package (TCP), which have lower wire resistance as compared with the wires of the integrated circuit.
Therefore, it is possible to prevent a voltage drop, that has been caused by wire resistance (especially, a power supplying wire) of the integrated circuit when a number of TCPs are connected in a conventional construction, which uses merely the wires of the integrated circuit for transmitting input signals and supplying electricity. For example, this arrangement makes it possible to prevent a degradation in display quality of a liquid crystal display device. Furthermore, with this arrangement, the signal transmitting wires are disposed in a horizontal space of the tape substrate, so that this arrangement can have virtually the same external dimension as the arrangement without signal transmitting wire.
Additionally, it is possible to overlay the input leads of the tape substrate onto the signal transmitting wires of another tape substrate so as to connect the input leads to the signal transmitting wires. In this case, a shift tends to occur between the input leads and the signal transmitting wires due to an error upon overlaying the tape substrate onto the other. Meanwhile, in the above-mentioned arrangement, the input leads and the signal transmitting wires are disposed on the same tape substrate so as to regulate an error occurring upon overlaying the tape substrate (shift upon folding the tape substrate). Consequently, it is possible to improve accuracy upon overlaying the input leads onto the signal transmitting wires.
For a fuller understanding of the nature and advantages of the invention, reference should be made to the ensuing detailed description taken in conjunction with the accompanying drawings.
REFERENCES:
patent: 4833568 (1989-05-01), Berhold
patent: 63684 (1994-01-01), None
Gyouten Seijirou
Tamai Shigeki
Abraham Fetsum
Sharp Kabushiki Kaisha
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