JPS6161389A - Multileads connecting method - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to a connection method for connecting an extraction electrode provided on a rigid flat display panel and a flexible printed circuit board using an anisotropic conductive film.

<Prior art> In recent years, rigid flat display panels with a matrix electrode configuration have been actively developed, and thin film E
L (electroluminescent) panels, plasma display panels, liquid crystal dot matrix panels, etc. are being commercialized.

These panels have a large number of fine extraction electrodes, and require one-to-one interconnection with drive elements. It is required that this interconnection be performed reliably and inexpensively.

Conventionally, solder has been mainly used for such terminal connections, but as panels become larger and pitches become finer, problems such as solder bridges and thermal deformation of connection materials due to high-temperature processing have arisen.

It is a polymer film that allows permanent adhesion, conduction between corresponding electrodes, and insulation between patterns at the same time without selecting a specific pattern pitch, and has a lower processing temperature than soldering. This method also has the advantage of not requiring a terminal film. Therefore, it is judged to be the most suitable material to solve the above-mentioned problems with solder.

As a connection method using this anisotropic conductive film, a hot press method is generally used, in which the connecting part between the lead electrode part of the flat display panel and the flexible printed circuit board is pressurized using a block with a built-in heater and bonded by thermocompression. Are known.

FIG. 8 is a front view showing the configuration of a conventional example.

As shown in FIG. 8, a flat display panel 33 is set on a pedestal 38, an anisotropic conductive film 39 is sandwiched between the flexible printed circuit boards 34, and the flexible printed circuit board 34 is aligned and then temporarily fixed. A block 41 containing a heater can be moved vertically by an air cylinder or the like, and is heated to a set temperature by the heater, and a silicone rubber 40 is attached to the tip of the block 41 to uniformly transmit pressure to the connection part. ing.

With the above configuration, the connection is completed by sliding the bulb a including the heater, the joint 41, and the silicone rubber 40 downward and thermocompressing the connection portion.

However, although this method has the advantage of being able to process the process all at once and in a relatively short processing time, it also increases the temperature of the joint during thermocompression bonding, and the heater is not turned on while the temperature of the joint remains high. Since the containing block is removed, problems arise such as stretching of the flexible printed circuit board and deformation of the connection material due to residual stress.Furthermore, this can lead to connection failures such as poor conductivity and poor insulation, resulting in high-fine pitch .

Problems remain in terms of application to larger screens.

<Object of the invention> Therefore, the object of the present invention is to enable connection using an anisotropic conductive film instead of solder, prevent connection failures due to elongation or deformation of the connection material during connection, It is an object of the present invention to provide an effective method for making high-fine pitch connections possible.

<Structure of the invention> In order to achieve the above object, the structure and operation of this invention are as follows.
The panels to be connected are overlapped and fixed on the flexible printed circuit board, hydrostatic pressure is applied to the bottom surface of the flexible printed circuit board, and a heat source such as infrared rays provided above the panel is directed to a specific one of the multiple connection terminals. Focus the light,
Connect the terminals using an anisotropic conductive film, then move the heat source and connect the next terminal adjacent to the already connected terminal. It is characterized by expanding in the scanning direction and completing connections between all terminals.

<Example> Hereinafter, the present invention will be described in detail along with the apparatus used to carry out the present invention.

Figure 1 shows the planar view of the device for implementing the present invention, and Figure 2 shows the first view.
FIG. 3 is a perspective view showing the heat source scanning means shown in the figure, and FIG. 3 is a sectional view of the infrared spot lamp shown in FIG. 1 or 2. Figure 6 is a half plan view showing the configuration of the jig used in the above device;
The figure is also a half-sectional side view.

Figure 6 and! In Figure g7, there are gaskets 23 at several locations on the flange portion 22 of the container 21, which is made of deep-drawn metal material.
The periphery of the film 27 is tightened and fixed using the holding metal 24, the bolts 25a and 25b, and the nut 26. Therefore, the container 21 and the film 27 form an airtight chamber 28.

In short, the film 27 is airtight, can be elastically deformed under high temperature and high pressure, has heat resistance and mechanical strength, and is, for example, a polyimide film.

At the bottom of the container 21, an inflow pipe 29 for gas such as air, nitrogen gas, water, oil, etc. is provided. several clips 3
0 is fixed at one end to the flange 22 by a tightening bolt 25, and at the other end is pressed against a hard substrate 33 by a substrate holding jig 32 via a height adjustment screw 31. The clip 30 presses the flexible substrate 34 and at the same time presses the film holding jig 36 via the spacer 35 with its arm portion. The film holding jig 36 is made of a strong material such as metal that does not deform under the maximum pressure applied to the airtight chamber 28 and has an appropriate thickness. Since the substrates 33 and 34 are pressed so that they are almost in one plane,
The contact area at the connecting portion becomes large despite the presence of the step, and a sufficiently strong connection is achieved.

As shown in the figure, in order to connect the flexible substrate 34 to each of the four sides of the substrate 33, the film holding jig 36 is formed over the entire outer periphery of the substrate 33. A heat radiating plate 37 is provided to block the heat rays received by the substrate holding jig 32 and to improve cooling at that part.

In the above connection device, infrared rays are emitted from the direction of arrow A shown in the figure.

Next, in FIGS. 1, 2, and 3, the scanning means for moving the small infrared spot lamp 1 along the connection terminal strip includes a drive unit 2, a feed screw 3, a guide shaft 4, a carriage 5
, a relay device 6. The small infrared spot lamp 1 is supported by an arm 7 on a carriage 5. The carriage 5 moves along the guide shaft 4 in parallel to the connection terminal strip. As shown in FIG. 3, the small infrared spot lamp 1 consists of an infrared lamp 8 and a reflector 9. The infrared rays generated by the infrared lamp 8 are reflected by the reflector 9,
The reflected light is focused at a focal point.

Next, an embodiment of the present invention, ie, a method of using the above-described apparatus, will be described. Infrared rays are focused on one point on the connection terminal strip,
The holding jig 36 and the clip 30 are adjusted so as not to be heated, the driving speed of the feed screw 3 is set, and the end point of scanning is set by the limit switch 6. The infrared lamp 8 moves according to the drive of the feed screw 3, and the flexible film 2
The leads on 7 and the terminals on substrate 33 are successively heated and connected.

In addition, as a modified embodiment of the present invention, it is also possible to use four heat sources and connect each side in parallel.

FIG. 4 is a diagram illustrating adhesive force when connecting according to the present invention. In order to determine the connection state between the substrate 10 and the lead wire 11, the tensile strength when the lead wire 11 was peeled off from the substrate 10 in the vertical direction was measured. Figure 5 is 1.3
An example of measurement when connected at a pitch of 3 wood/Ichi is shown.

Since the anisotropic conductive film 12 is bonded not only under the lead wire 11 but also between adjacent leads by infrared irradiation, a larger bonding area can be expected compared to solder which connects only the lead portions.

Another embodiment of the present invention will be described below with reference to FIG.

FIG. 9 is a sectional view showing the wooden sword method. Liquid crystal cell 46 (4
The structure is the same as the conventional one up to the point where an anisotropic conductive film 43 and an FPC (flexible printed circuit board) 42 are combined with a polarizing plate 5. Next, the liquid crystal cell terminal section 44 is placed on the holding rubber plate 52 with the terminal section facing downward. The rubber plate is molded from silicone rubber. Next, place the presser glass 51 on top of the liquid crystal cell, and then place the upper presser metal fitting 5 on top of it.
Put 0. The presser metal fitting 50 is fixed to the lower presser metal fitting 53 with a tightening bolt 49. In addition, the part of the holding fitting 50 that corresponds to the liquid crystal cell terminal part is hollowed out (
54: <cutout part). Next, pressure F is applied to the lower presser fitting 53 so that a predetermined pressure is applied substantially to the terminal portion of the liquid crystal cell. After making preparations in this manner, the liquid crystal cell terminal portion is heated by the infrared irradiation lamp 47. The infrared irradiation lamp 47 gradually moves over the terminals of the liquid crystal cell in its length direction (from the front to the back of the drawing) by means of guide rails 48 and sequentially irradiates the terminals with light to heat them.

By using the wooden sword method, the anisotropic conductive film 43 is melted and crimped at the part that is irradiated with light by the infrared lamp 47 while pressure is applied.Moreover, as the infrared lamp moves, the melted and crimped part is melted and crimped. The product is naturally cooled while still retaining the water, which greatly improves quality. Also, the temperature is 2~
It reached nearly 200°C in 3 seconds, and reached 50-60°C in 2-3 seconds.
Since it is cooled to ℃, there is no deterioration in workability.

Note that the upper presser metal fitting 50 also functions as a mask material for shielding light (heat rays).

Although the above embodiment has been described using the connection between a liquid crystal cell and an FPC, its implementation is not limited to liquid crystal cells. For example, it could be applied to EL panels, etc. It may also be used to connect a PWB (printed wiring board) and an FPC.

Furthermore, instead of moving the infrared irradiation lamp, one display body, the anisotropic conductive film, and the FPC may be moved.

As the pressure application method, a method other than the hydrostatic pressure method may be used.

Moreover, it is also possible to use a heat seal connector instead of (FPC in an anisotropic conductive film).

, PA, -゛〈Effects of the Invention〉 According to the present invention, only the connection points are heated locally, and the heating points are moved sequentially, so the amount of residual heat in the flexible film is significantly reduced. , distortions caused by thermal expansion and adhesive misalignment between leads and terminals have been eliminated.

In addition, in general, in the sequential connection method using local heating,
A stress difference occurs between the connected part and the unconnected part due to the melting and solidification of the anisotropic conductive film, which tends to cause "warpage" and "undulation" due to uneven stress distribution over the entire surface. For example, since the entire surface of the connection part is pressurized with a constant hydrostatic pressure, the pressure acts evenly even if there are warps or undulations at the raw opening, resulting in a reliable connection between the wire and the terminal.

In addition, even if the panel has warps or undulations, the pressure acts uniformly as described above, and a reliable connection can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a plan view illustrating an embodiment of the present invention. FIG. 2 is a perspective view illustrating a hot ray source feeding means according to an embodiment of the present invention. FIG. 3 is a sectional view of a small infrared spot lamp. FIG. 4 is a diagram illustrating adhesive force in connection according to an embodiment of the present invention. FIG. 5 is a diagram showing an example of measurement of adhesive force according to an embodiment of the present invention. FIG. 6 is a half sectional view showing the structure of the present invention. FIG. 7 is a half-sectional side view showing the structure of the present invention. FIG. 8 is a front view showing a conventional connection method. Explanation of the dlh resistance or 1 meter code in the fc lettering of No. qt/ζ wood vinegar J3 1...Infrared small spot lamp, 2...Drive unit, 3...Feed screw, 4...
・Guide shaft, , 5... Reciprocating table, 88.・1 Ruu - Post Office 91...Address Brother - 27...Film,
28...airtight chamber, 30...clip, 33...
・Hard substrate (panel), 34...Flexible substrate. Agent Patent Attorney Aihiko Fukushi (and 2 others) Figure 2 Figure 3 1υ Figure 4 Figure 5 No. 612 JHNA Figure 7

Claims (1)

[Scope of Claims] 1. A connection device in which a connection part between an extraction electrode part provided on a rigid flat display panel and a flexible printed circuit board is bonded using an anisotropic conductive film, the flexible printed board as described above. The above-mentioned panel is stacked and fixed on top of the flexible printed circuit board, hydrostatic pressure is applied to the lower surface of the above-mentioned flexible printed circuit board, and a heat source such as infrared rays provided above the panel is focused on the above-mentioned joint to anisotropically transform the joint. 1. A multi-lead connection method, characterized in that the connection is made using a conductive film, and then all connections are completed by sequentially moving the heat source.