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`(12) United States Patent
`US 6,583,845 B1
`(10) Patent N0.:
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`Chung et al. Jun. 24, 2003 (45) Date of Patent:
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`USOO6583845B1
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`(54) LIQUID CRYSTAL DISPLAY DEVICE AND
`METHOD OF FABRICATING THE SAME
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`(75)
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`(73)
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`(*)
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`Inventors: Nag Su Chung, Kumi (KR); Ju Sung
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`Ch0, Kumi (KR)
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`Assignee: LG.Philips LCD C0., Ltd., Seoul (KR)
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`Subject to any disclaimer, the term of this
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`patent is extended or adjusted under 35
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`U.S.C. 154(b) by 452 days.
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`Notice:
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`Appl. No.:
`Filed:
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`(21)
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`(22)
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`(30)
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`09/585,399
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`Jun. 2, 2000
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`Foreign Application Priority Data
`(KR) ........................................ 2000—08667
`Feb. 23, 2000
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`(51)
`Int. Cl.7 .......................... G02F 1/1345; H05K 7/10
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`(52) US. Cl. ................. 349/150; 349/149; 361/769
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`(58) Field of Search ................................. 349/150, 152,
`349/149; 361/749, 777; 174/250
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`(56)
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`(57)
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`ABSTRACT
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`References Cited
`U.S. PATENT DOCUMENTS
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`5,889,572 A *
`3/1999 Takahashi et a1.
`.......... 349/149
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`6,323,930 B1 * 11/2001 Higuchi et a1.
`............. 349/152
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`* cited by examiner
`Primary Examiner—Toan Ton
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`Assistant Examiner—Dung Nguyen
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`(74) Attorney, Agent,
`or Firm—McKenna,
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`Aldridge LLP
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`Aliquid crystal display having dummy pads that are capable
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`of fortifying a bonding force between a tape carrier package
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`and a liquid crystal panel. In the liquid crystal display, the
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`tape carrier package has first and second dummy pads to
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`Which signals are not applied. The first dummy pad has a
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`larger Width than the second dummy pad. The liquid crystal
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`panel has third and fourth dummy pads corresponding to the
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`first and second dummy pads, respectively.
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`9 Claims, 6 Drawing Sheets
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`Long &
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`62
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`70 72
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`66
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`68
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`Page 1 of 10
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`Tianma Exhibit 1010
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`Page 1 of 10
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`Tianma Exhibit 1010
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`US. Patent
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`Jun. 24, 2003
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`Sheet 1 0f 6
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`US 6,583,845 B1
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`FIG.
`1
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`CONVENTIONAL ART
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`4V—{:1
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`10
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`FIG. 2
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`CONVENTIONAL ART
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`2\—
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`s—
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`- T
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`6 —
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`14
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`.12
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`US. Patent
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`Jun. 24, 2003
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`Sheet 2 0f 6
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`US 6,583,845 B1
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`FIG. 3
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`CONVENTIONAL ART
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`”NE E?”
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`17
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`4:
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`Page 3 of 10
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`US. Patent
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`Jun. 24, 2003
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`Sheet 3 0f 6
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`US 6,583,845 B1
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`FIG. 4
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`CENVENTIONAL ART
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`US. Patent
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`Jun. 24, 2003
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`Sheet 4 0f 6
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`US 6,583,845 B1
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`FIG. 5
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`CONVENTIONAL ART
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`22,24
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`US. Patent
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`Jun. 24, 2003
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`Sheet 5 0f 6
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`US 6,583,845 B1
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`FIG. 6
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`CONVENTIONAL ART
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`42
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`50 52
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`48
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`US. Patent
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`Jun. 24, 2003
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`Sheet 6 0f 6
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`US 6,583,845 B1
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`FIG. 7
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`62
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`70 72
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`68
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`70d
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`7DC
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`70b
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`70a
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`Page 7 of 10
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`Page 7 of 10
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`1
`LIQUID CRYSTAL DISPLAY DEVICE AND
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`METHOD OF FABRICATING THE SAME
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`US 6,583,845 B1
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`2
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`As shown in FIG. 4, the TCP 12 employed in the TAB
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`system includes a base film 22 on which is mounted an IC
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`14. The base film 22 is also provided with input and output
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`pads 24 and 26 connected to input and output pins of the ICs
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`14. The input and output pads 24 and 26 have a two-layer
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`structure in which copper(Cu) is plated with tin(Sn) for
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`preventing an oxidation. Line widths of the input pads 24 are
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`set to be larger than those of the output pads 26. As shown
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`in FIG. 5,
`the input pads 24 of the base film 22 are
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`connected, via an anisotropic conductive film (ACF) 30, to
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`pads 28 on the PWB 6. The output pads 26 are also
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`connected via the ACF 30 to pads 28 on the liquid crystal
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`panel 2.
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`Recently, in order to fortify a bonding force between the
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`liquid crystal panel and the TCP 42, separate dummy pads
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`50 and 52 have been provided at a liquid crystal panel 44 and
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`a TCP 42 as shown in FIG. 6. The dummy pads 50 and 52
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`function to increase a bonding force between the TCP 42 and
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`the liquid crystal panel 44 by widening a bonded area
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`without being connected to a signal wiring. The dummy
`pads 50 and 52 are bonded to each other with the ACF 30
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`therebetween upon bonding the output pads 46 of the TCP
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`42 to the gate/data pads 48 of the liquid crystal panel 44.
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`Line widths of the dummy pads 52 and 54 are set to be equal
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`to those of the output pads 46 of the TCP 42 and the
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`gate/data pads 48 of the liquid crystal panel 44. Accordingly,
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`the bonding forces of each dummy pad 50 and 52 are the
`same.
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`However,
`the TCP 42 and the liquid crystal panel 44
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`having the conventional dummy pads have a problem in that,
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`since the bonding forces of each dummy pad 50 and 52 are
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`same, a bonding force generated by the dummy pads 50 and
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`52 is not satisfactory. As a result, in the liquid crystal display
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`with the conventional dummy pads, the TCP 42 can be
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`separated from the liquid crystal panel 44 due to an impact
`force applied from the exterior thereof in the course of its
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`fabrication process or its usage. The conventional TCPs 12
`and 42 have limited usefulness because of such weak
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`bonding force.
`SUMMARY OF THE INVENTION
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`Accordingly, it is an object of the present invention to
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`provide a liquid crystal display having dummy pads with an
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`increased bonding force between a tape carrier package and
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`a liquid crystal panel.
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`A further object of the present invention is to provide a
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`method of fabricating a liquid crystal display having dummy
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`pads that with an increased bonding force between a tape
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`carrier package and a liquid crystal panel.
`In order
`to achieve these and other objects of the
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`invention, a liquid crystal display with dummy pads accord-
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`ing to one aspect of the present invention includes a tape
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`carrier package including first and second dummy pads to
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`which signals are not applied, the first dummy pad having a
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`larger width than the second dummy pad; and a liquid crystal
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`panel including third and fourth dummy pads corresponding
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`to the first and second dummy pads, respectively.
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`A liquid crystal display with dummy pads according to
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`another aspect of the present
`invention includes a tape
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`carrier package including output pads for outputting signals
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`from an integrated circuit and dummy pads to which signals
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`are not applied, at least one of said dummy pads having a
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`width different from the output pads; and a liquid crystal
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`panel including dummy pads corresponding to said dummy
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`pads.
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`A method of fabricating a liquid crystal display with
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`dummy pads according to still another aspect of the present
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`BACKGROUND OF THE INVENTION
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`This application claims benefit of Korean patent applica-
`tion number P2000-08667, filed Feb. 23, 2000, which is
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`hereby incorporated by reference for all purposes as if fully
`set forth herein.
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`FIELD OF THE INVENTION
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`This invention relates to a liquid crystal display having a
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`tape carrier package including a mounted integrated circuit,
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`and more particularly to a tape carrier package with dummy
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`pads that are capable of fortifying a bonding force in
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`bonding the tape carrier package onto a liquid crystal panel.
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`Also, the present invention is related to a method of fabri-
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`cating a liquid crystal display with dummy pads that are
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`capable of fortifying a bonding force between the tape
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`carrier package and the liquid crystal panel.
`DESCRIPTION OF THE RELATED ART
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`Generally, an active matrix liquid crystal display uses thin
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`film transistors (TFTs) as switching devices to display a
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`natural-looking moving picture. Since such a liquid crystal
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`display can be made into a smaller-size device than a
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`cathode ray tube,
`it is commercially viable for use as a
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`monitor such as a portable television,
`lap-top personal
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`computer or other consumer device.
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`The active matrix liquid crystal display displays a picture
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`corresponding to video signals such as television signals on
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`a pixel (or picture element) matrix having pixels arranged at
`each intersection between gate lines and data lines. Each
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`pixel includes a liquid crystal cell for controlling a trans-
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`mitted light quantity in accordance with a voltage level of a
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`data signal from a data line. A TFT (thin film transistor) is
`installed at an intersection between a gate line and a data line
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`to switch a data signal to be transferred to the liquid crystal
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`cell in response to a scanning signal (i.e., a gate pulse) from
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`the gate line.
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`Such a liquid crystal display requires a number of inte-
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`grated circuits (ICs) connected to the data lines and the gate
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`lines to apply data signals and scanning signals to the data
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`lines and the gate lines, respectively. The ICs are installed
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`between the print wiring board (PWB) and the liquid crystal
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`panel to apply signals supplied from the PWB to the data
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`lines and the gate lines. IC mounting methods include chip
`on board, hereinafter referred to as “COB”, tape automated
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`bonding, hereinafter referred to as “TAB”, and chip on glass,
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`hereinafter referred to as “COG”. (Other methods are also
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`possible.) The COB system is ainly used for a monochro-
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`matic liquid crystal display having a pixel pitch of more than
`300 pm. As shown in FIG. 1, in this COB system, ICs 8 are
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`mounted on a PWB 6 and a heat-seal connector 10 connects
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`the PWB 6 and a glass substrate 3 in a liquid crystal panel
`2. In this case, a back light unit 4 used as a light source is
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`provided between the liquid crystal panel 2 and the PWB 6.
`As shown in FIG. 2, in the TAB system, ICs 14 are mounted
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`on a tape carrier package (TCP) 12. The TCP 12 is connected
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`between the PWB 6 and the liquid crystal panel 3. As shown
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`in FIG. 3, in the COG system, an IC chip 20 is directly
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`mounted on a glass substrate 17 in a liquid crystal panel 16.
`The above mentioned TAB IC mounting method has been
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`widely employed because it can widen an effective area of
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`the panel and has a relatively simple mounting process.
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`US 6,583,845 B1
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`3
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`invention includes the steps of forming first and second
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`dummy pads on the tape carrier package in such a manner
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`that the first dummy pad has a width different from the
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`second dummy pad; forming third and fourth dummy pads
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`corresponding to the first and second dummy pads,
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`respectively, on the liquid crystal panel; and bonding the
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`tape carrier package on the liquid crystal panel in such a
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`manner that the first and second dummy pads correspond to
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`the third and fourth dummy pads, respectively.
`BRIEF DESCRIPTION OF THE DRAWINGS
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`These and other objects of the invention will be apparent
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`from the following detailed description of the embodiments
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`of the present invention with reference to the accompanying
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`drawings, in which:
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`FIG. 1 is a sectional view showing the structure of a liquid
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`crystal display employing the conventional chip on board
`system;
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`FIG. 2 is a sectional view showing the structure of a liquid
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`crystal display employing the conventional tape automated
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`bonding system;
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`FIG. 3 is a sectional view showing the structure of a liquid
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`crystal display employing the conventional chip on glass
`system;
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`FIG. 4 is a detailed perspective view of the tape carrier
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`package shown in FIG. 2;
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`FIG. 5 is a plan view showing a connection state between
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`the input and output pads of the tape carrier package and the
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`pads on the liquid crystal panel or the print wiring board in
`FIG. 2;
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`FIG. 6 is a plan view showing the bonding of the tape
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`carrier package and the liquid crystal panel having the
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`conventional dummy pads; and
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`FIG. 7 is a plan view showing the bonding of the tape
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`carrier package and the liquid crystal panel having dummy
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`pads according to an embodiment of the present invention.
`DETAILED DESCRIPTION OF THE
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`PREFERRED EMBODIMENT
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`Referring to FIG. 7, a TCP 62 and a liquid crystal panel
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`64 of a liquid crystal display according to an embodiment of
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`the present invention include first and second dummy pad
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`groups 70 and 72, wherein a width of at least one dummy
`pad in each group set to be different from the widths of
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`output pads 66 and signal pads 68 in such a manner to have
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`a different bonding force. The TCP 62 is provided with
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`output pads 66 connected to a signal wiring in parallel to
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`dummy pads having a different line width. The first dummy
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`pad group 70 of the TCP 62 includes a first dummy pad 70a,
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`a second dummy pad 70b and a fourth dummy pad 70d that
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`have the same line width, and a third dummy pad 706 having
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`a larger line width than the dummy pads 70a, 70b and 70d.
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`The third dummy pad 706 has a larger line width than the
`first, second and fourth dummy pads 70a, 70b and 70d or the
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`output pads 66. For instance, the third dummy pad 706 is
`formed to have a line width of more than twice the line width
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`of the first, second and fourth dummy pads 70a, 70b and 70d
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`or the output pads 66. Because the line width of dummy pad
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`706 is greater, the surface area available for bonding on the
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`TCP 62 is more effectively used.
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`The liquid crystal panel 64 is provided with signal pads 68
`connected to the gate lines and the data lines in parallel to
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`the output pads 66 and the dummy pads 72 of the TCP 62
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`and the second dummy pad group 72 on a rear glass
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`substrate 63. The second dummy pad group 72 includes a
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`first dummy pad 72a, a second dummy pad 72b and a fourth
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`dummy pad 72d having a small line width to be opposed to
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`the respective pads 70a, 70b and 70d of the first dummy pad
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`group 70, and a third dummy pad 726 having a larger line
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`width than the dummy pads 72a, 72b and 72d. The third
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`dummy pad 726 has a larger line width than the first, second
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`and fourth dummy pads 70a, 70b and 70d or the signal pads
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`68 like the third dummy pad 706 of the TCP 62. For instance,
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`the third dummy pad 726 is formed to have a line width of
`more than twice the line width of the first, second and fourth
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`dummy pads 72a, 72b and 72d or the signal pads 68.
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`Upon bonding of the TCP 62 to the liquid crystal panel 64,
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`the dummy pads 70 and 72 are bonded to each other with the
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`ACF 30 therebetween. If the dummy pads 70 and 72 are
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`bonded in this manner,
`then the bonding force of each
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`dummy pad becomes different in accordance with the line
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`width thereof. In other words, the first dummy pads 70a and
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`the second dummy pads 70b and 72b and the fourth
`72a,
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`dummy pads 70d and 72d have the same bonding force,
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`whereas the third dummy pads 70c and 726 have a larger
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`bonding force than the dummy pads 70a and 72a; 70b and
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`72b; and 70d and 72d. Those of skill in the art will recognize
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`that it is also possible to provide all dummy terminals with
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`a greater
`line width than non-dummy terminals.
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`Furthermore, it is also possible to provide a single terminal
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`with an elongated width, such as a single terminal having a
`width equal to the combined width of terminals 70a—d and
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`the space there between.
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`As described above, the liquid crystal display according
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`to the present invention includes dummy pads with a dif-
`ferent
`line width in such a manner to have a different
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`bonding force,
`thereby increasing the bonding force. A
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`method of fabricating a liquid crystal display according to
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`the present invention includes the steps of forming dummy
`pads with a different line width at both of the TCP and the
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`liquid crystal panel in such a manner that a bonding force
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`exerting on each dummy pad is different, thereby fortifying
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`a bonding force between the TCP and the liquid crystal
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`panel.
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`Accordingly, a bonding force between the TCP and the
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`liquid crystal panel is increased, so that the liquid crystal
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`display can be normally operated even when subjected to a
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`large impact and force from the exterior thereof.
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`Although the present invention has been explained in
`connection with the embodiments shown in the drawings
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`described above, it should be understood by a person of
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`ordinary skill in the art that the invention is not limited to
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`these embodiments, but rather that various changes or modi-
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`fications thereof are possible without departing from the
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`spirit of the invention. Accordingly, the scope of the inven-
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`tion shall be determined only by the appended claims and
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`their equivalents.
`What is claimed is:
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`1. A liquid crystal display, comprising:
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`a tape carrier package including first and second dummy
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`pads to which no signals are applied, the first dummy
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`pad having a larger width than the second dummy pad;
`and
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`a liquid crystal panel including third and fourth dummy
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`pads corresponding to the first and second dummy
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`pads, respectively.
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`2. The liquid crystal display according to claim 1, wherein
`one of said dummy pads has a width of more than twice the
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`width of other dummy pads.
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`3. A liquid crystal display, comprising:
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`a tape carrier package including a plurality of output pads
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`for outputting signals from an integrated circuit and at
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`10
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`Page 9 of 10
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`Page 9 of 10
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`6
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`least one dummy pad on the tape carrier
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`*
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`*
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`*
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`forming at
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`package;
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`wherein each dummy pad has a width greater than a width
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`of at least one signal pad.
`6. The method of claim 5, wherein the width of each
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`dummy pad is at least twice the width of the at least one
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`signal pad.
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`7. The method of claim 5, further comprising the steps of
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`forming additional dummy pads on the tape carrier package
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`and the liquid crystal panel.
`8. The method of claim 7, wherein widths of the addi-
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`tional dummy pads are greater than widths of the dummy
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`9. The method of claim 7, wherein widths of the addi-
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`tional dummy pads are equal to widths of the dummy pads.
`*
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`US 6,583,845 B1
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`5
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`least one first dummy pad to which signals are not
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`applied, the at least one first dummy pad having a width
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`different from a width of the output pads; and
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`a liquid crystal panel
`including at
`least one second
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`dummy pad corresponding to said first dummy pad.
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`4. The liquid crystal display according to claim 3, wherein
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`said first and second dummy pads have a width of more than
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`twice a width of the output pads.
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`5. A method of fabricating a liquid crystal display com-
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`prising the steps of:
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`providing a liquid crystal panel;
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`forming a plurality of signal pads on the liquid crystal
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`paneh
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`forming at least one dummy pad on the liquid crystal
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`paneh
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`providing a tape carrier package;
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`forming a plurality of signal pads on the tape carrier
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`package; and
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`10
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`Page 10 of 10
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`Page 10 of 10
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