JP2001066621A - Tape carrier package for driving liquid crystal - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve reliability of soldered connection of a circuit substrate with input signal electrodes of a tape carrier package(TCP) for driving a liquid crystal of a liquid crystal display device. SOLUTION: In the TCP 10 for driving a liquid crystal, wherein a base film 2 is provided with an opening for mounting an LSI element 1 and output signal terminals 4 and input signal electrodes 5 of the LSI element 1, projecting into the opening of the film, and the LSI element 1 is mounted in the opening with the output signal terminals 4 and the input signal electrodes 5 connected, the base film 2 between the LSI element 1 and the end parts of the input signal electrodes 5 is provided with a notch part, and the notch part is filled with flexible resin 50 except soldering terminals 8 of a connection part with the circuit board of the input signal electrodes 5, and the input signal electrodes on the flexible resin 50 are provided with wiring curve parts 3a.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tape carrier package for driving a liquid crystal, and more particularly to a tape carrier package which is disposed around a liquid crystal panel display element and on which a liquid crystal driving integrated circuit element is mounted.

[0002]

2. Description of the Related Art A display device using liquid crystal has features such as low power and light weight which are not present in a conventional display, and its commercial power has been enhanced by the advancement of peripheral technology, and it has been used in various products. Among them, an active matrix type liquid crystal display device using thin film transistors as a switch for each pixel can provide a clear image display without crosstalk. It is used for displays and the like, and its market is rapidly expanding.

In order to supply signals to a liquid crystal panel, as shown in FIG. 5, a liquid crystal driving integrated circuit element (hereinafter abbreviated as an LSI element) 1 is formed by folding a base film 2 made of a polyimide film or the like. Copper foil (thickness 10 to 35 μm
), Mounted on a tape carrier package (hereinafter abbreviated as TCP) 10 on which the wiring 3, the output signal electrode 4, and the input signal electrode 5 are formed, and the surface of the LSI element 1 is coated with a protective material (not shown). .

[0006] Next, the TCP 10 is cut from the cutting outline 6, and as shown in FIG. 6, the signal line connection terminal 21 on the liquid crystal panel 20 and the output signal electrode 4 (shown in FIG. 5) on the TCP 10 are connected. The connection is performed by pressure welding using an anisotropic conductive material (hereinafter abbreviated as ACF) (not shown). The signal supply to the TCP 10 is performed by connecting the input signal electrode 5 of the TCP 10 to an electrode (not shown) formed on the circuit board 30 by soldering. As shown in FIG. 5, an opening 7 is formed on the input signal electrode 5 side of the base film 2 of the TCP 10, and a soldering terminal 8 is provided. The soldering terminal 8 is connected to an electrode (see FIG. (Not shown).

The wirings other than the openings of the input signal electrodes of the TCP 10 are adhered to a base film 2 made of polyimide, and are formed substantially linearly up to the IC chip including the exposed solder terminals 8. I have.

When the TCP 10 is soldered to the circuit board 30, a temperature of 260 to 300 ° C., which is the melting point of the solder, is applied to the circuit board 30 connected to the soldering terminal 8, and the TCP 10 and the circuit board 30 are expanded. Is connected and held.

[0007] As the soldering is completed and the TCP and the circuit board return to room temperature (cool), a stress in the contraction direction is applied to both due to a difference in the coefficient of thermal expansion. This stress increases as the length of the connection portion, the difference between the coefficients of thermal expansion thereof, and the difference between the soldering temperature and the use environment temperature increase.

[0008]

The circuit board 30 formed by laminating a copper foil and a glass cloth with an epoxy resin has a length close to the entire length of the liquid crystal panel as shown in FIG.
Much longer. Further, as described above, since the wiring of the TCP 10 is formed in a straight line, the TCP itself cannot absorb the stress generated at the time of cooling by soldering.

For this reason, the shrinkage stress (indicated by a thick arrow in FIG. 6) generated when the soldering is completed and the TCP and the circuit board return to room temperature is also applied to the liquid crystal panel 20 via the TCP 10. Due to this stress, the alignment state of the liquid crystal near the side to which the TCP 8 is connected changes, and there is a problem that a display abnormality (see a display abnormal part 60 in FIG. 6) occurs.

Further, since the wiring of the TCP 10 is made of a thin copper foil having a thickness of 15 to 20 μm as described above, the mechanical strength is inferior, and the TCP 10 is easily broken at the boundary with the base film (A in FIG. 6). There was a problem.

FIG. 7 shows this state. First, the circuit board 3
By the contraction of 0, the soldering terminal 8 of the TCP is pulled in the direction of the arrow. On the other hand, the base film 2 is made of polyimide having a thickness of about 70 μm, and is superior in mechanical strength to the wiring of the solder terminal 8. For this reason, the soldering terminal 8 is broken at the boundary surface with the base film (see the terminal portion broken portion 9 in FIG. 7).

As a method for absorbing a stress due to a difference in thermal expansion between a circuit board of a liquid crystal display device and a TCP in an operating environment, Japanese Patent Application Laid-Open Nos. 10-22086 and 11-1 are disclosed.
No. 21682 discloses an LSI for a TCP base film.
A method is disclosed in which a slit is provided between an element mounting portion and an input signal electrode of a TCP, a slit resist is filled with a soft polyimide resin, and the input signal electrode is joined to a circuit board by ACF. Even when the technique is applied to the connection between the circuit board and the TCP by soldering, it is not possible to prevent the wiring of the input signal electrode of the TCP from being broken.

As another method for preventing breakage of the input signal electrode of the TCP, measures to reduce the size of the circuit board by narrowing the space between the soldering terminals in FIG. 3 and arranging the TCP as close as possible to the TCP are studied. However, with the rapid progress of higher resolution and larger LCD screens, sufficient effects cannot be obtained and the yield and quality cannot be improved.

An object of the present invention is to provide a TCP mounted with a liquid crystal driving integrated circuit device which solves the above-mentioned problems of the prior art.

[0015]

According to the present invention, an opening for mounting an LSI element is provided on a flexible base film.
An output signal terminal and an input signal electrode of the LSI element are provided so as to protrude inside the opening on one surface of the film,
In the liquid crystal driving TCP configured by mounting the LSI element in the opening by connecting to the output signal terminal and the input signal electrode, the other of the LSI element and the other of the input signal electrode connected to the LSI element. A cutout portion is provided in the base film in a region where the input signal electrode is disposed between the end portion and the cutout portion, and the cutout portion is adjacent to the connection portion except for a connection portion between the input signal electrode and a circuit board. The structure is characterized by a structure in which the LSI element side is filled with a flexible resin.

As the soft resin, a soft polyimide resin, polyurethane resin, butadiene rubber or the like can be used.

In the above configuration of the present invention, a space between the side surfaces of the input signal electrode provided on the flexible resin may be filled with the flexible resin, and upper and lower surfaces of the input signal electrode may be filled with the flexible resin. May be coated.

In the present invention, the wiring shape of the input signal electrode on the flexible resin is curved, or the shape of the input signal electrode on the flexible resin is larger than the width of the input signal electrode outside the flexible resin region. It may be circular, oval, or rectangular with the largest width.

According to the present invention, as described above, a notch is provided in the base film between the connection portion of the input signal electrode to the circuit board and the LSI element, and the signal electrode installation region of the notch is provided. By providing a flexible resin to the
This resin can effectively absorb the stress caused by the difference in thermal expansion between the circuit board and the TCP when the TCP is soldered to the circuit board. Also, by bending the wiring of the input signal electrode in the flexible resin region, or by making the maximum width of the input signal electrode in the flexible resin region larger than the width of the input signal electrode outside the flexible resin region, The stress of the flexible resin can be more effectively absorbed, and the display quality stability of the liquid crystal display device can be improved.

[0020]

Next, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a plan view (a) and a sectional view (b) of a liquid crystal driving TCP according to a first embodiment of the present invention, as viewed from the wiring side. FIG. 1 (b) is a view taken from A- of FIG. 1 (a).
It is sectional drawing which followed the A 'line. As shown in FIG.
A wiring 3 formed of a copper foil of 5 to 20 μm is attached to a base film 2 made of a polyimide resin, and the LSI element 1 is connected from an opening of the base film 2 to an end of the output signal terminal and the input signal electrode within the opening. Mount and connect with solder or the like. A cutout portion is provided on the input signal electrode side of the base film 2, and a soft resin 50 is provided in the cutout portion except for an opening 7 for exposing a soldering portion (soldering terminal 8) of the input signal electrode. Is filled.

In this figure, the lower side of the TCP 10 is a portion to be connected to the circuit board by soldering, and the wiring exposed in the opening 7 becomes the soldering terminal 8 to be soldered to the circuit board. T
The upper side of CP10 is a liquid crystal panel and an anisotropic conductive resin (AC
This is the portion to be pressed in F). The soldering terminal 8 portion is first cut out of the base film 2 so as to include the portion where the flexible resin 50 is to be attached and the opening 7, and then the portion that exposes the terminal length required for soldering (the soldering terminal 8 portion). Except for (1), a flexible resin film is applied between the opening 7 and the base film 2 or a liquid resin is applied to insulate the resin. Here, the wiring of the portion bonded to the flexible resin is configured to be bent in a stepwise manner as in the wiring curved portion 3a of FIG.

As a material of the flexible resin 50, a soft polyimide resin, polyurethane resin, butadiene rubber or the like can be used. The flexible resin 50 is formed so as to fill the space between the wirings of the wiring curved portion 3a, or the flexible resin 50 is
May be formed so as to cover the upper and lower surfaces and the side surfaces.
By forming the flexible resin in this manner, the flexible resin 50 is formed.
The adhesion of the input signal electrode 5 in the region to the flexible resin 50 can be improved.

Next, the operation of the first embodiment of the present invention will be described with reference to FIG. In using the TCP 10, first, the base film 2 is punched out by a die or the like along a cutting outline 6 indicated by a dotted line, and cut into predetermined dimensions. The separated TCP 10 has its upper side (output signal terminal 4 side) pressed against the liquid crystal panel using ACF, and the lower (input signal electrode 5 side) soldering terminal 8 having an opening is soldered to the circuit board. .

According to the present invention, the flexible resin 50 is attached between the opening 7 having the soldering terminal 8 of the base film 2 and the mounting portion of the LSI element 1, and the wiring is bent to form a flexible structure. I have.

The TCP 10 and the circuit board are connected and held in a state expanded by the heat of soldering. The stress caused by the contraction when the soldering is completed and the circuit board and the TCP 10 return to normal temperature (cooled) can be absorbed by the deformation of the flexible structural part.
Disconnection of the input signal electrode 5 of the TCP due to the stress generated by the difference in thermal expansion of the TCP.

The structure of the wire bending portion 3a may be a bow-shaped structure as shown in FIG. 3 or a bent shape as shown in FIG. 4. Even with these structures, the same effect as in FIG. Obtainable. 3 and 4, (a) is a plan view, (b) is a cross-sectional view taken along the line AA ′ of (a), and the same reference numerals as those in FIG. Is shown.

Next, a TCP for driving a liquid crystal according to a second embodiment of the present invention will be described with reference to FIG. FIG. 2 is a plan view (a) and a cross-sectional view (b) of a liquid crystal driving TCP according to a second embodiment of the present invention, as viewed from the wiring side. FIG. 2B is a cross-sectional view taken along line AA ′ of FIG. 2A.

In the present embodiment, the shape of the curved wiring portion 3a of the wiring 3 in FIG. 1 is circular (see the circular wiring portion 3b in FIG. 2).
And In this embodiment, by making the shape of the wiring 3 on the flexible resin into a circle, the TC 3 of the first embodiment described above is used.
There is an effect that the adhesive strength with the flexible resin 50 is improved as compared with P, so that the stress absorption when the soldering terminal 8 of the input signal electrode 5 is soldered to the circuit board can be improved. Note that the diameter of the wiring circular portion needs to be larger than the width of the wiring connected to it. The same effect can be obtained by changing the shape of the circular wiring portion 3b to an elliptical or rectangular shape having a width larger than the wiring width at both ends. The flexible resin 50 may be formed so as to fill the space between the wirings on the flexible resin, or may be formed so as to cover the upper and lower surfaces and the side surfaces of the wiring on the flexible resin, as in the first embodiment. .

[0030]

As described above, according to the present invention, the TCP
Of connection of input signal electrode to circuit board and TCP LSI
Notches are provided in the base film for TCP between devices,
The following effects can be obtained by providing a flexible resin in the input signal electrode arrangement region of the cutout portion and making the input signal electrode in the flexible resin region curved or the like.
(1) This flexible resin can effectively absorb the stress caused by the difference in thermal expansion between the circuit board and the TCP when the TCP is soldered to the circuit board, and can prevent the input signal electrode from being broken. (2) As a result, it is possible to improve the production yield of the liquid crystal panel and the display quality stability of the liquid crystal display device.

[Brief description of the drawings]

FIG. 1 is a plan view and a sectional view of a liquid crystal driving TCP according to a first embodiment of the present invention.

FIG. 2 is a plan view and a cross-sectional view of a liquid crystal driving TCP according to a second embodiment of the present invention.

FIG. 3 is a plan view and a cross-sectional view of a liquid crystal driving TCP according to another embodiment of FIG. 1;

FIG. 4 is a plan view and a sectional view of a liquid crystal driving TCP according to another embodiment of FIG. 1;

FIG. 5 is a plan view and a sectional view of a conventional liquid crystal driving TCP.

FIG. 6 is a plan view of a liquid crystal display device on which a conventional liquid crystal driving TCP is mounted.

FIG. 7 is an enlarged plan view of a conventional connection portion between a liquid crystal driving TCP and a circuit board.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 LSI element 2 Base film 3 Wiring 3a Wiring curved part 3b Wiring circular part 4 Output signal electrode 5 Input signal electrode 6 Cutting outline 7 Opening 8 Soldering terminal 9 Terminal part broken part 10 TCP 20 Liquid crystal panel 30 Circuit board 50 Flexible Resin 60 display abnormal part

Claims (7)

[Claims] An opening for mounting an LSI element is provided in a flexible base film, and an output signal terminal and an input signal electrode of the LSI element are provided on one surface of the film inside the opening so as to protrude therefrom. In a liquid crystal driving tape carrier package configured by mounting the LSI element by connecting to the output signal terminal and the input signal electrode, the other end of the LSI element and the other end of the input signal electrode connected to the LSI element A cutout portion is provided in the base film in an area where the input signal electrode is disposed between the cutout portion and the cutout portion, adjacent to the connection portion except for a connection portion between the input signal electrode and a circuit board. A liquid crystal drive tape carrier package, characterized in that the LSI element side is filled with a flexible resin. 2. The liquid crystal drive tape carrier package according to claim 1, wherein a soft polyimide resin, urethane resin, or butadiene rubber is used as the soft resin. 3. The liquid crystal drive tape carrier package according to claim 1, wherein a space between the input signal electrode side surfaces disposed on the flexible resin is filled with the flexible resin. 4. The liquid crystal drive tape carrier package according to claim 1, wherein side surfaces and upper and lower surfaces of the input signal electrodes provided on the flexible resin are covered with the flexible resin. . 5. The liquid crystal drive tape carrier package according to claim 1, wherein a wiring shape of the input signal electrode on the flexible resin is curved. 6. The tape carrier package for driving a liquid crystal according to claim 5, wherein the curved shape of the input signal electrode on the flexible resin is a step shape or a bow shape. 7. The wiring shape of the input signal electrode on the flexible resin is circular, elliptical, or rectangular, and the maximum width of the circular, elliptical, or rectangular input signal electrode is the flexible resin. 2. The liquid crystal drive tape carrier package according to claim 1, wherein the width of the input signal electrode other than above is larger than the width of the input signal electrode.