JPH11153964A - Liquid crystal display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To extremely reduce the internal thermal stress of a tape carrier package LSI after connection when the input terminals of the tape carrier package LSI in which the output terminals are connected to a liquid crystal panel, are heat-pressed to a printed circuit wiring board. SOLUTION: In this liquid crystal display 12, an input terminal 3 of a tape carrier package LSI 1 on which a liquid crystal driving LSI 5 is mounted, is connected to a terminal 71 of a printed circuit wiring board 7 and an output terminal 2 is connected to a terminal 61 of a liquid crystal panel 6. Opening sections 4 which reduce the rigidity in a planer direction, are formed on the flexible board of a region P1, where the terminal 3 of the LSI 1 and the terminal 2 are formed, and other than a region P2 where the LSI 5 is mounted. Then, the terminal 3 is connected to the terminal 71 and the terminals 2 and 61 are connected through anisotropic electrically conductive adhesive sheets 8, 8.

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 LSI for connecting a liquid crystal panel and a printed circuit board to each other.
The present invention relates to a liquid crystal display device connected by using a liquid crystal display.

[0002]

2. Description of the Related Art As a method of connecting a tape carrier package LSI connected to a liquid crystal panel and a printed circuit wiring board, a method using soldering and a method using an anisotropic conductive adhesive sheet are known.

The former connection method by soldering has been used in the past, but with the recent increase in the definition of liquid crystal panels, the input terminals of the tape carrier package LSI have been miniaturized. A short circuit between them has become a problem, and a method using an anisotropic conductive adhesive sheet that allows connection at a narrower pitch has been widely used.

[0004]

FIG. 4 shows a conventional tape carrier package LSI (9), a liquid crystal panel (6) and a printed circuit board via an anisotropic conductive adhesive sheet (8).
9 shows a cross section of a liquid crystal display device (12) to which (7) is connected.

The order of connection of these liquid crystal display devices (12) is as follows: first, the output terminal (11) of the tape carrier package LSI (9).
The terminal (61) of the liquid crystal panel (6) and the anisotropic conductive adhesive sheet
(8), and then the input terminal (10) of the tape carrier package LSI (9) and the printed circuit wiring board (7)
To the terminal (71) through an anisotropic conductive adhesive sheet (8).

This is because the connection pitch between the liquid crystal panel (6) and the output terminal (11) of the tape carrier package LSI (9) is
This is because the printed circuit wiring board (7) and the input terminal (10) of the tape carrier package LSI are small.

However, in the conventional connection method, as shown in FIG. 4, the tape carrier package LSI (9)
And the printed circuit board (7), the tape carrier package LSI (9) and the printed circuit board (7)
And a problem arises in that distortion occurs.

This is a tape carrier package LSI.
The output terminal (11) of (9) is already connected and fixed to the liquid crystal panel (6), and in this state, the printed circuit wiring board (7) and the input terminal (10) of the tape carrier package LSI (9) are connected. The printed circuit wiring board (7) and the tape carrier package LSI (9) extend mainly in the width direction (the direction of the paper back in FIG. 4 and the direction of the arrow in FIG. 5) due to the heating at the time of connection.
In that state, the anisotropic conductive adhesive sheet (8) is cured.

When the temperature returns to normal temperature after connection, the printed circuit wiring board (7) and the tape carrier package LSI (9) contract in the direction opposite to the arrow in FIG. 5 due to the thermal expansion. The tape carrier package LSI (9) cannot absorb this shrinkage amount, and the tape carrier package LSI (9) is distorted.

In particular, the tape carrier package L of FIG.
Since the distortion is accumulated toward both ends (9A) and (9B) in the width direction of the SI (9), the distortion increases. As a result, there has been a problem that a signal line provided in the tape carrier package LSI (9) is disconnected, and an abnormality occurs on a display screen of the liquid crystal display device (12).

An object of the present invention is to solve the above-mentioned conventional problems and to provide a highly reliable liquid crystal display device.

[0012]

According to a first aspect of the present invention, there is provided a liquid crystal display device including a region in which an input terminal and an output terminal of a tape carrier package LSI are formed, and a liquid crystal driving LSI mounted thereon. An opening for lowering the rigidity in the planar direction is formed in the flexible substrate of the liquid crystal driving LSI other than the region where the liquid crystal is driven.

According to this configuration, the printed circuit wiring board and the tape carrier package LSI expand during the heating connection, but the shrinkage when the temperature returns to the normal temperature after the connection is absorbed by the flexible board whose rigidity in the plane direction is reduced. The internal stress of the tape carrier package LSI after the connection can be extremely reduced, and the disconnection of the signal line and the like can be eliminated, and high reliability can be secured.

According to a second aspect of the present invention, in the liquid crystal display device according to the first aspect, the opening is formed by two or more slits extending in a direction perpendicular to a side where the input terminal and the output terminal are formed.

At the same time, the stress is reduced by the slits, and the local stress generated around the slits is reduced by using two or more slits. According to a third aspect of the present invention, in the liquid crystal display device of the second aspect, two or more slits are respectively provided at symmetrical positions sandwiching the liquid crystal driving LSI on the flexible substrate.

By forming the slits symmetrically on the flexible substrate, the stress distribution can be made uniform.

[0017]

According to a first aspect of the present invention, there is provided a liquid crystal display device wherein an input terminal connected to an input pad portion of the liquid crystal driving LSI is formed on one side of a flexible substrate on which the liquid crystal driving LSI is mounted. Using a tape carrier package LSI having a region in which an output terminal connected to an output pad portion of the liquid crystal driving LSI is formed on a side opposite to a side of the region in which the input terminal is formed, and In a liquid crystal display device connected to a terminal of a printed circuit wiring board and the output terminal connected to a terminal of a liquid crystal panel, a region where the input terminal and the output terminal of the tape carrier package LSI are formed and the liquid crystal drive An opening for reducing rigidity in a planar direction is formed in a flexible substrate other than a region where the LSI is mounted, and the input terminal is connected to an end of the printed circuit wiring board. And the said output terminal terminals of the liquid crystal panel is made by connecting via an anisotropic conductive adhesive sheet.

With this configuration, the output terminals of the tape carrier package LSI are already connected to the liquid crystal panel, and the tape carrier package LSI is fixed.
Printed circuit wiring board and tape carrier package LS
When heat is applied to the input terminal of I, the printed circuit wiring board and the tape carrier package LSI expand by heating during connection, but after the connection, the contraction of the expanded printed circuit wiring board when the temperature returns to normal temperature is opened. Since the internal stress of the tape carrier package LSI after connection can be extremely reduced, high reliability can be ensured.

According to a second aspect of the present invention, in the liquid crystal display device of the first aspect, the opening is a slit extending in a direction perpendicular to a side where the input terminal and the output terminal are formed. It is characterized by being formed side by side.

The direction of expansion and contraction of the tape carrier package LSI due to heat during heating and cooling is the direction along the side of the flexible substrate on which the input terminals are provided. Therefore, by providing a slit in a direction perpendicular to this side, expansion and contraction in a direction along the side is reduced. In addition, if the number of slits is two or more, the expansion of the printed circuit wiring board due to heat and pressure can be reduced by only one tape carrier package LSI
This is because not only can not fully absorb but also stress such as vibration and impact after the liquid crystal display device is incorporated into the product concentrates on one slit, which adversely affects the slit.

If the number is two or more, the stress generated around the slit is dispersed, and the influence on the overall strength is greatly reduced. According to a third aspect of the present invention, in the liquid crystal display device of the second aspect, two or more slits are provided at symmetrical positions sandwiching the liquid crystal driving LSI on the flexible substrate.

The stress relaxation state generated in the flexible substrate is caused to be symmetrical with respect to the center of the substrate to prevent irregular distortion due to the uneven stress relaxation state. Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a plan view showing an embodiment of a tape carrier package LSI according to the present invention.
FIG. 2 is a sectional view of a liquid crystal display device connected by using the tape carrier package LSI of FIG.

In FIG. 2, the liquid crystal panel (6) is made of a light-transmitting glass substrate, on which an aluminum electrode (hereinafter referred to as "Al electrode") (61) is formed.

The thickness of the Al electrode (61) is usually from 2000 to 30.
It is about 00 °. An anisotropic conductive adhesive sheet (8) in which conductive particles are dispersed is attached to the surface of the Al electrode (61).

At this time, the state is temporarily fixed, and the pressing temperature is 1
00 to 150 ° C. As the anisotropic conductive adhesive sheet (8), CP7621F manufactured by Sony Chemical Corporation was used.
Next, the output terminal of the tape carrier package LSI (1)
(3) and the Al electrode (61) of the liquid crystal panel (6) faced each other, and were aligned and overlapped.

After that, the tape carrier package LSI
From the (1) side, heat and pressure is applied with a constant heating type bonding tool, and the output terminal of the tape carrier package LSI (1)
(3) and the Al electrode (61) of the liquid crystal panel (6) were electrically connected.

At this time, the heat press conditions are 190 ° C., 40 k
gf / cm 2 and 20 sec. In order to more evenly apply heat and pressure, a cushioning material is provided between the bonding tool and the tape carrier package LSI (1).
A Teflon sheet (not shown) having a thickness of 0 μm was inserted.

The printed circuit wiring board (7) is made of glass / epoxy and has a thickness of 1.0 mm. Input terminal of tape carrier package LSI (1)
Connection terminal (7) of printed circuit board (7) connected to (2)
1) 0.02 to 3-5 μm thick nickel plating
The flash gold plating of 0.03μm thickness is applied,
It is patterned at a pitch of 300 μm.

Connection terminal (71) of printed circuit wiring board (7)
Anisotropic conductive adhesive sheet with conductive particles dispersed on top
(8) is adhered. At this time, a temporary fixing state was set as described above, and the pressure bonding temperature was 70 to 80 ° C.

As the anisotropic conductive adhesive sheet (8), CP7652K manufactured by Sony Chemical Corporation was used. Next, the input terminals (2) of the tape carrier package LSI (1) and the connection terminals (71) of the printed circuit wiring board (7) faced each other, and were aligned and overlapped.

After that, the tape carrier package LSI
From the (1) side, heat and pressure is applied by a constant heating bonding tool, and the input terminal of the tape carrier package LSI (1)
(2) and the connection terminal (71) of the printed circuit wiring board (7) were electrically connected.

At this time, the heat press conditions are 190 ° C., 40 k
gf / cm 2 and 20 sec. In order to more evenly apply heat and pressure, a cushioning material is provided between the bonding tool and the tape carrier package LSI (1).
A Teflon sheet (not shown) having a thickness of 0 μm was inserted, and a silicon rubber (not shown) having a thickness of 300 μm was further inserted thereon. At this time, the hot pressing condition is 180 ° C., 30 ° C.
kgf / cm2 and 20 sec.

As the tape carrier package LSI (1) used in the above steps, after the printed circuit wiring board (7) is heated and pressurized, the printed circuit wiring board (7) is stretched when the temperature returns to normal temperature. In order that the tape carrier package LSI (1) absorbs the shrinkage of the tape carrier package LSI, the area P1 where the input terminal (2) and the output terminal (3) are formed and the liquid crystal driving LSI (5) are mounted. The slits (4)... (4) extending in a direction parallel to the input terminal (2) and the output terminal (3) of the tape carrier package LSI (1) are formed in the flexible substrate 1A in the region P2 other than the region where ,
A liquid crystal display device (12) was assembled by preparing two units each arranged side by side and a tape carrier package LSI (9) having no slit at all, and providing them to the above steps.

When the abnormal rate of the display screen was examined for a large number of assembled liquid crystal display devices, the defective rate of less than 1% was obtained using the same tape carrier package LSI (9) as the conventional example having no slit. However, in the case of using the tape carrier package LSI (1) of the present invention, the defect occurrence rate was almost zero.

The tape carrier package LSI (1)
The slits (4)... (4) are not limited to the shape as shown in FIG.
If there is a flexible substrate at both ends of the liquid crystal driving LSI (5) other than the area (P1) where the input terminal and the output terminal are formed and the area where the liquid crystal driving LSI (5) is mounted,
Any shape such as a circle, an ellipse, an oblong, a crescent, a triangle, or a combination thereof may be used.

[0037]

As described above, according to the liquid crystal display device of the present invention, the output terminal of the tape carrier package LSI is already connected to the liquid crystal panel, and the tape carrier package LS
When the printed circuit wiring board and the input terminal of the tape carrier package LSI are heated and pressurized in a state where I is fixed, the printed circuit wiring board and the tape carrier package LSI are stretched by heating at the time of connection. By providing an opening, the tape carrier package LSI having reduced rigidity can be absorbed by providing an opening to expand the contraction of the printed circuit wiring board when the temperature returns to normal temperature, and the internal stress of the tape carrier package LSI after connection is extremely small. Therefore, high reliability can be ensured.

Further, the slit extending in the direction perpendicular to the side where the input terminal and the output terminal of the tape carrier package LSI are formed is formed in the portion where the dimensional change at the time of hot pressing is the largest, that is, the input terminal of the tape carrier package LSI. And a liquid crystal driving L other than a region where the output terminal is formed and a region where the liquid crystal driving LSI is mounted.
By providing the flexible printed circuit board at both ends of the SI, the shrinkage of the printed circuit wiring board can be reduced by the tape carrier package LS.
I can absorb more.

[Brief description of the drawings]

FIG. 1 is a plan view of a tape carrier package LSI according to claim 1;

FIG. 2 is a sectional view of a liquid crystal display device connected using the tape carrier package LSI of FIG. 1;

FIG. 3 is a plan view of a conventional tape carrier package LSI.

FIG. 4 is a cross-sectional view of a liquid crystal display device connected using a conventional tape carrier package LSI.

FIG. 5 is an enlarged view of a liquid crystal display device connected using a conventional tape carrier package LSI.

[Explanation of symbols]

Reference Signs List 1 Tape carrier package LSI of the present invention 2 Input terminal of tape carrier package LSI of the present invention 3 Output terminal of tape carrier package LSI of the present invention 4 Slit 5 LSI for driving liquid crystal 6 Liquid crystal panel 7 Printed circuit wiring board 8 Anisotropic conductivity Adhesive sheet 9 Conventional tape carrier package LSI 10 Input terminal of conventional tape carrier package LSI 11 Output terminal of conventional tape carrier package LSI 12 Liquid crystal display

Claims (3)

[Claims] 1. A region in which an input terminal connected to an input pad of the liquid crystal driving LSI is formed on one side of a flexible substrate on which the liquid crystal driving LSI is mounted, and a side of the region in which the input terminal is formed. The input terminal is connected to a terminal of a printed circuit wiring board using a tape carrier package LSI having a region where an output terminal connected to an output pad portion of the liquid crystal driving LSI is formed on a side opposite to the above. In a liquid crystal display device in which an output terminal is connected to a terminal of a liquid crystal panel, a flexible portion other than a region where the input terminal and the output terminal of the tape carrier package LSI are formed and a region where the liquid crystal driving LSI is mounted are provided. An opening for reducing rigidity in a planar direction is formed in the flexible substrate, and the input terminal is connected to the terminal of the printed circuit wiring board and the output terminal is connected to the liquid crystal panel. A liquid crystal display device characterized by comprising of a terminal connected via an anisotropic conductive adhesive sheet. 2. The liquid crystal display device according to claim 1, wherein the opening is a slit extending in a direction perpendicular to a side where the input terminal and the output terminal are formed, and two or more slits are formed side by side. A liquid crystal display device characterized by the above-mentioned. 3. The liquid crystal display device according to claim 2, wherein two or more slits are respectively provided at symmetrical positions sandwiching the liquid crystal driving LSI on the flexible substrate.