JP2002350889A - Liquid crystal display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a printed circuit board having a structure by which the quality for connecting the printed circuit board to a flexible wiring board can be enhanced. SOLUTION: In a liquid crystal display device wherein a plurality of panel terminal groups formed at least one side of a liquid crystal display panel 5 and a plurality of printed circuit board terminal groups formed at the printed circuit board 1 are respectively connected to each other via the flexible wiring board 3, a notched part 6 is formed at the outer peripheral part of the printed circuit board 1 and in at least one part between a terminal group of the part between the printed circuit board terminal groups.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device, and more particularly to a liquid crystal display device in which a plurality of flexible wiring boards connected to a liquid crystal display panel and a printed board are electrically connected via an adhesive material.

[0002]

2. Description of the Related Art Generally, a liquid crystal display panel 11 built in a liquid crystal display device is driven by a group of panel terminals formed on a side portion of the liquid crystal display panel 11, as shown in FIG. Panel terminal group (not shown)
(Tape Carrier Package) and other flexible wiring boards 1
3 is electrically connected to a terminal group (not shown) formed at one end of the flexible wiring board 1.
A terminal group (not shown) formed at the other end of the circuit board 3 is electrically connected to a printed circuit board terminal group formed on a printed circuit board 12 such as a bus board or a circuit board. This is performed by supplying necessary signals to the liquid crystal display panel 11 via the flexible wiring board 13.

In the step of connecting the liquid crystal display panel 11 to the flexible printed circuit board 13 and the flexible wiring board 13 to the printed circuit board 12, the panel terminals provided on the liquid crystal display panel 11 correspond to the terminals. The output terminal provided on the flexible printed circuit board 13, the input terminal provided on the flexible printed circuit board 13, and the corresponding printed circuit board terminal provided on the printed circuit board 12 are connected to each other by using a dedicated crimping device 14. The connection is usually made through an adhesive material 15 such as an anisotropic conductive film or solder.

FIGS. 3A and 3B are explanatory views showing main parts of the general crimping device 14, wherein FIG. 3A is a front view of the main parts, and FIG.
FIG.

[0005] The crimping device 14 includes an air cylinder 16A.
A heater block 17 that is moved up and down by the heater block driving device 16 is attached to the lower surface side of the heater block driving device 16.

Below the heater block 17, the panel terminals of the liquid crystal display panel 11, the output terminals of the flexible wiring board 13, and the flexible wiring board 13
Input terminal formed on the other end of the printed circuit board 12
The heater block 18 for thermocompression bonding the printed circuit board terminals mounted on the
Is fixed so as to protrude from the lower surface.

The heater block 17 has a built-in heater 19 for heating the heater bar 18.

Further, the liquid crystal display panel 11 and the flexible wiring board 13 or the flexible wiring board 13
A mounting table (not shown) for mounting the printed circuit board 12 is provided.

Next, a panel terminal of the liquid crystal display panel 11, an output terminal of the flexible wiring board 13, an input terminal formed at the other end of the flexible wiring board 13, and a printed circuit board terminal of the printed circuit board 12 are connected. A connection method using the crimping device 14 will be described taking the latter connection as an example.

When connecting the input terminal formed at the other end of the flexible wiring board 13 to the printed board terminal of the printed board 12, first, the printed board 12 is placed on the mounting table, and the terminal is placed on the upper surface. And place it so that it is exposed. Then, an adhesive material 15 such as an anisotropic conductive film is arranged above the printed circuit board terminals. Next, the flexible printed circuit board 13 already connected to the liquid crystal display panel 11 is placed above the printed circuit board 12 such that the printed circuit board terminals of the printed circuit board 12 and the corresponding input terminals of the flexible printed circuit board 13 face each other. Align and place. Then, the heater bar 18 heated by the heater 19 is lowered by driving the air cylinder 16A to the upper surface of the portion where the printed circuit board terminal and the input terminal of the flexible wiring board 13 face each other. The printed circuit board 1 via the adhesive material 15
2 and the flexible wiring board 13 are electrically connected by thermocompression bonding.

By the way, as shown in FIG. 4, the connection method using the heater bar 18 includes all the flexible wiring boards for each side of the liquid crystal display panel 11 to which the plurality of flexible wiring boards 13 are connected. 13, the flexible wiring board 13 is attached to each side of each side as shown in FIG.
Connection method (hereinafter, individual crimping method) and FIG. 6
As shown in (1), there is a method in which a plurality of adjacent flexible wiring boards 13 are divided into groups each of which is adjacent to each side and connected to each of the groups (hereinafter referred to as a divided pressure bonding method).

The crimping device 14 shown in FIG. 3 is a crimping device 14 used in the case of the collective crimping method. Also,
The crimping device 14 used for the individual crimping method and the split crimping method is different from the crimping device 14 used for the collective crimping method of FIG.
It is assumed that moving means for relatively moving the heater block 6, the heater block 17, and the like in the arrangement direction of the flexible wiring boards 13 is provided.

[0013]

When terminals are connected by using the above-described crimping device 14, the printed circuit board 12 is temporarily heated and pressurized at the time of connection with the flexible wiring board 13. It shows thermal stress that elongates at the connection part and shrinks to return to its original size again by cooling (including natural cooling) after connection, and finally elongates from the original printed circuit board 12 It will be.

The thermal stress of the printed circuit board 12 may cause the printed circuit board terminal of the printed circuit board 12 to be aligned with the input terminal of the other end of the flexible wiring board 13 before the heat compression bonding. Eventually, the two terminals are displaced at the time of connection, resulting in a problem that connection stability between the printed circuit board 12 and the flexible wiring board 13 is deteriorated.

In particular, when the printed circuit board 12 and the flexible wiring board 13 are electrically connected by the collective pressure bonding method, the thermal expansion and contraction of the printed circuit board 12 at the time of connection is large, and the above-mentioned problems are remarkable. Had become. After the connection, the printed circuit board 12 tends to return to the original size as the heat of the printed circuit board 12 is released,
A large force is constantly applied to the connection part, and in the worst case, the connection part between the printed circuit board 12 and the flexible wiring board 13 or the connection part between the flexible wiring board 13 and the liquid crystal display panel 11 may be separated. .

To solve this problem, as shown in FIG. 7A, the expansion and contraction of the printed circuit board 12 during thermocompression bonding is taken into account, and the printed circuit board 12 is reduced in advance and formed. As shown in FIG. 7B, after the crimping, the printed circuit board 12 is positioned so that the corresponding printed circuit board terminal 12A and the input terminal 13A of the flexible printed circuit board 13 are properly aligned. It is also being studied to form the printed circuit board terminals by correcting the positions of the terminals. However, this method uses the printed circuit board 1
There is another problem in that numerical data for the correction must be obtained every time the design is changed.

When the connection between the printed circuit board 12 and the flexible wiring board 13 is performed by using the individual pressure bonding method and the split pressure bonding method,
2, since the thermal shrinkage is small, the above-mentioned problem of connection quality is less likely to occur than in the case of using the collective pressure bonding method. However, a plurality of pressure bonding operations are required per side of the printed circuit board 12. There was a problem that productivity was poor.

The present invention has been made in view of these points, and in particular, in a connection method using a crimping device, a liquid crystal having a connection structure that can improve the connection quality between a printed board and a flexible wiring board. It is an object to provide a display device.

[0019]

According to a first aspect of the present invention, there is provided a liquid crystal display device comprising: a plurality of panel terminal groups formed on at least one side of a liquid crystal display panel; In a liquid crystal display device in which a plurality of printed circuit board terminal groups formed on a printed circuit board for supplying signals to a liquid crystal display panel are connected via a flexible wiring board, respectively, at an outer peripheral portion of the printed circuit board, and A notch is formed in at least one of the printed circuit board terminal groups.

According to the first aspect of the present invention, even if the printed circuit board expands and contracts due to its thermal stress during thermocompression bonding, the expansion and contraction can be buffered by the notch, so that it is arranged on the printed circuit board. Misalignment between the terminal and the terminal of the flexible wiring board can be reduced to such a degree that the connection quality is not supported.

According to a second aspect of the present invention, in the liquid crystal display device according to the first aspect, the notch is formed between all adjacent printed circuit board terminal groups. Features.

According to the second aspect of the present invention, expansion and contraction of the printed circuit board during thermocompression bonding can be buffered in the minimum unit.

According to a third aspect of the present invention, in the liquid crystal display device according to the first or second aspect, the notch formed in the printed circuit board has a notch forming side having a depth. Is formed in a substantially rectangular shape having a size not less than the dimension up to the side opposite to the notch forming side in the formation portion of the printed circuit board terminal group, and having a width of not less than 0.5 mm and not more than the dimension between adjacent printed circuit board terminal groups. It is characterized by having.

According to the third aspect of the present invention, by securing the notch depth, the expansion and contraction direction of the printed board requiring alignment at the connection portion between the printed board and the flexible wiring board is completely divided. By ensuring the width of the notch, the expansion and contraction of the printed circuit board portion divided by the notch during thermocompression bonding can be sufficiently buffered.

[0025]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIG.

The printed board shown in FIG. 1 is a bus board 1 for supplying external signals, and a plurality of flexible wiring boards TCP 3 are connected to the bus board 1. A plurality of printed circuit board terminals 2 are formed on a portion of the bus board 1 where the individual TCPs 3 are connected, and the plurality of printed circuit board terminals 2 and the plurality of input terminals 4 formed on the TCP 3 are connected to each other. They are arranged to face each other and are electrically connected by an anisotropic conductive film (not shown). The printed circuit board terminal group is an individual TCP3.
Of the printed circuit board terminals 2 connected to
One printed circuit board terminal group corresponds to each TCP3. The same can be said for the panel terminal group. The hatching shown at the right end of TCP 3 in FIG. 1 indicates a connection portion of the terminal, and is not shown in other TCPs.

The bus board 1 according to the present embodiment is formed in a long and substantially rectangular shape, and one side in the longitudinal direction is arranged along one side of the liquid crystal display panel 5.

The width of the bus board 1 is determined by connecting the TCP 3 and the bus board 1 to each other.
The side of the TCP 3 on the side opposite to the liquid crystal display panel 5 is formed so as to fit in the bus board 1.

In the embodiment shown in FIG. 1,
The printed board terminal 2 is formed on the upper surface side of the bus board 1 on the side opposite to the liquid crystal display panel, and when the TCP 3 is connected to the bus board 1, the input terminal 4 of the TCP 3 and the printed board terminal 2 are overlapped. Bus board 1 positioned
A constant width (hereinafter, connection width) in the width direction is a connection portion.

On the side of the bus board 1 close to the connection site, a notch 6 for buffering a change in expansion and contraction due to thermal stress of the bus board body 1A at the time of connection is formed between adjacent TCPs 3. Have been.

The notch 6 has a notch depth equal to or greater than the dimension between the notch forming side of the bus board 1 and the anti-notch forming side at the connection portion between the input terminal 4 of the TCP 3 and the printed circuit board terminal 2. The bus board body 1A is formed in a substantially rectangular shape having a width dimension capable of buffering shrinkage due to thermal stress of the bus board body 1A. In other words, in the embodiment shown in FIG. 1, the notch 6 is formed on the side of the liquid crystal display panel opposite to the side where the printed circuit board terminal 2 is formed, with a width of 0.5 mm or more, which is equal to or less than the arrangement interval of the TCP 3. And the TC
A substantially rectangular shape having a notch depth equal to or greater than the width obtained by adding the connection width to the misalignment width (tip protrusion width) between the side of the liquid crystal display panel on P3 and the side of the bus substrate 1 on the anti-liquid crystal panel side. Is formed.

By securing the notch depth in this way, the expansion and contraction direction of the bus board main body 1A which needs to be aligned can be completely divided at the connection portion of the bus board 1, and the notch 6 By securing the width dimension,
The expansion and contraction at the time of thermocompression bonding of the bus substrate body 1A divided by the notch 6 can be sufficiently buffered.

Next, a bus board 1 as a printed board and a TCP as a flexible wiring board according to this embodiment
3 will be described. Note that the crimping device 14 used in the present embodiment is the crimping device 14 for performing the above-described collective crimping connection, and a description thereof will be omitted. The components of the crimping device 14 will be described using the same reference numerals as in the conventional example.

First, the bus board 1 is mounted on the mounting table of the crimping device 14 such that the printed circuit board terminals 2 aligned in a line face upward. Next, an anisotropic conductive film 7 as an adhesive material is disposed on the upper surface of the printed circuit board terminal 2, that is, on the connection site.
P3 is connected to the printed circuit board terminal 2 and the input terminal 4 of the TCP.
Are placed above the bus substrate 1 while performing positioning so that the substrates face each other.

Then, the heater bar 18 heated to a predetermined temperature (about 200 ° C.) by the heater 19 of the crimping device 14 is connected to the connection portion where the printed board terminal 2 and the input terminal 4 of the TCP are aligned. The printed circuit board terminals 2 aligned on the bus board 1 are thermocompression-bonded at a time via the corresponding TCP input terminals 4 and the anisotropic conductive film 7, respectively.

At this time, the bus board 1 having the shape having the notch 6 as in the present embodiment is expanded and contracted at the connection portion of the bus board body 1A due to heating and pressurization when connecting the terminals. Can be buffered by the notch 6 formed between the adjacent printed circuit board terminal groups. That is, the notch 6 can function as a buffer zone. Therefore, expansion and contraction of the bus board main body 1A can be reduced, and as described above, there is a problem of misalignment between the printed circuit board terminal 2 and the input terminal 4 of the TCP at the time of connection, separation of the connection portion after connection, and the like. Can be solved.

Hereinafter, the bus board 1 of this embodiment will be described.
Specific effects will be described as compared with the case where a conventional bus board is used.

As shown in FIG. 1, in a case where eight TCPs 3 connected to the liquid crystal display panel are connected to one side of the bus board 1, between the TCPs 3 located on both sides of the eight TCPs 3 When the distance dimension is 200 mm,
When the eight TCPs are connected to the conventional bus board having no notch formed thereon by the collective crimping method, the final extension dimension of the conventional bus board body is about 0.4.
mm, and the connection operation took about 20 seconds.

When the eight TCPs are connected to the conventional bus board having no notch by the individual crimping method, the extension of the conventional bus board body is about 0.1 mm. However, the connection took about 200 seconds.

On the other hand, the bus board 1 of this embodiment, in which the notch 6 is formed, is subjected to the collective pressure bonding method.
Bus board main body 1A when connecting three TCP3s
Was about 0.1 mm, and the time required for the connection operation was about 20 seconds.

As described above, the bus board 1 of the present embodiment is
Also in the connection method using the crimping device 14 of the collective crimping method, the same connection quality between the bus board 1 and the TCP 3 as in the case of employing the individual crimping method can be obtained. Since the required time is much shorter than the time required when the individual thermocompression bonding method is employed and the same as the time required when the batch compression bonding method is employed, the workability is not deteriorated. In addition, the thermal contraction of the bus board body 1A during thermocompression bonding is taken into account, and a good connection with the TCP 3 can be achieved without employing a complicated means such as reducing and forming the bus board 1 in advance. The quality can be obtained.

As described above, the present invention has a remarkable effect when the connection is performed by the collective compression bonding method. The expansion and contraction of the substrate due to the thermal stress can be buffered by the notch 6.

The present invention is not limited to the above embodiment, but can be variously modified as needed. For example, the formation side of the notch is not limited to the side opposite to the liquid crystal display panel as described above, and the formation of the notch need not necessarily be formed between all the terminal groups. For example, if the terminal group is 2
The crimping device may be of a split crimping type that enables crimping of two terminal groups by forming a notch between each group.

The connection member may be, for example, solder in addition to the anisotropic conductive film. Also in this case, the connection between the terminals is performed using a crimping device using the heater bar. The same effect as that of the embodiment can be obtained.

[0045]

As described above, the liquid crystal display device according to the present invention has the effects of improving the connection quality between the flexible wiring board and the printed board without lowering the productivity.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing the shape of a printed board (bus board) of a liquid crystal display device according to the present invention and the connection of the printed board to a flexible wiring board (TCP).

FIG. 2 is a schematic diagram showing a conventional general connection of a liquid crystal display panel, a flexible wiring board, and a printed board, and the shape of the conventional printed board.

FIG. 3 is a schematic view of a general crimping device, (A) is a front view thereof, and (B) is a side view thereof.

FIG. 4 is an explanatory view of a connection method when terminals are connected by a collective crimping method.

FIG. 5 is an explanatory diagram of a connection method when terminals are connected by an individual crimping method.

FIG. 6 is an explanatory diagram of a connection method when terminals are connected by a split crimping method.

FIG. 7A is a conceptual diagram showing a positional relationship between a terminal of a printed circuit board before thermocompression bonding and a terminal of a flexible printed circuit board, and FIG. Conceptual diagram showing the positional relationship between the terminals of the printed circuit board and the terminals of the flexible wiring board after crimping

[Explanation of symbols]

 Reference Signs List 1 bus board (printed board) 1A bus board main body 2 printed board terminal 3 TCP (flexible wiring board) 3A TCP main body 4 TCP input terminal 5 liquid crystal display panel 6 notch 7 anisotropic conductive film

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2H092 GA50 NA27 NA29 5E338 AA02 AA12 BB02 BB12 BB17 BB71 EE01 EE26 5E344 AA01 AA12 AA22 AA28 BB02 BB04 CC01 CC05 CC11 CD02 DD06 EE02 EE16 EE21 EE23

Claims (3)

[Claims] 1. A plurality of panel terminal groups formed on at least one side of a liquid crystal display panel, and a plurality of printed circuit board terminal groups formed on a printed circuit board for supplying signals to the liquid crystal display panel. A liquid crystal display device connected via a flexible wiring board, wherein a notch is formed in an outer peripheral portion of the printed board and at least one between each printed board terminal group. . 2. The semiconductor device according to claim 1, wherein the notch is formed between all adjacent printed circuit board terminal groups.
3. The liquid crystal display device according to 1. 3. The notch formed in the printed circuit board has a depth equal to or greater than a dimension from a notch forming side to a side opposite to the notch forming side in a portion where the printed circuit board terminal group is formed.
The liquid crystal display device according to claim 1, wherein the liquid crystal display device is formed in a substantially rectangular shape having a width of 0.5 mm or more and a dimension between adjacent printed circuit board terminal groups or less.