JP2000347592A - Method for connecting electrode terminals of flat display panel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress a short circuit from occurring between adjacent electrodes even if there are small conductive foreign matters, by thermally press-fixing an anisotropic conductive film so that electric connection parts between an electrode terminal group of the flat display panel and a conductive wire group of a flexible cable are in a staggered arrangement in the direction of the electrode terminal arrangement. SOLUTION: A flexible cable 3 is arranged to be opposed to electrode terminals 2. The flexible cable 3 is the one of which the base material is coated with a cladding material, and conductive wires 4 are coated with the cladding material except the connecting parts. An anisotropic conductive film 8 is provided between the display panel 1 and the flexible cable 3 to bring them into electric conduction. The flexible cable 3 is pressed on from the above by a press-fixing head 5 for heating. The press-fixing head 5 has plural projecting parts 6 in a staggered arrangement, and the anisotropic conductive film 8 is thermally press-fixed only at the parts contacted by the projecting parts 6 and they are brought into electric conduction.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for connecting a flexible cable to an electrode terminal of a flat display panel such as a plasma display panel (PDP) or a liquid crystal display panel (LCD).

2. Description of the Related Art Flat display panels tend to increase the number of display electrodes and shorten the pitch between the electrodes to improve the image quality, so-called high definition. It is being arranged at a pitch. Therefore, it is liable to be affected by minute foreign matter. However, there is a demand for a simple and reliable connection using a flexible cable while suppressing the influence of such foreign matter.

[0003]

2. Description of the Related Art A flexible connection structure of a plasma display device will be described as an example. FIG. 6 is a cross-sectional view and a plan view of the plasma display device.

FIG. 6A shows a plasma display device.
As shown in the cross-sectional view of FIG. 1, a display panel 31 formed by bonding a pair of glass substrates via a discharge space, and a circuit board 42 on which a circuit for driving the panel is mounted are mounted on a chassis 4.
1 and are electrically connected by a flexible cable 33.

As can be seen from the plan view of FIG. 6B, the connection by the flexible cable 33 is made at a plurality of locations around the display panel 31.

Display panel 31 and flexible cable 3
Reference numeral 3 denotes an electrically connected electrode terminal extending to the edge of the substrate of the display panel 31 and a conductive wire of the flexible cable 33 through a thermosetting or semi-thermosetting anisotropic conductive film. On the other hand, the circuit board 42 and the flexible cable 33
Are connected by a connector, and transmit an electric signal output from the circuit board 42 to the display panel 31 via the flexible cable 33.

[0007] The liquid crystal display device also has basically the same configuration as described above.

FIGS. 7A and 7B show a conventional connection technique using an anisotropic conductive film. FIG. 7A is a cross-sectional view for explaining a connection step by thermocompression bonding, and FIG. 7B is a sectional view showing electrode terminals and conductive wires after thermocompression bonding. 3 is a plan view showing a connection state of FIG.

[0009] As shown in FIG.
Is placed on a stage 37, and a flexible cable 33 is arranged on an electrode terminal 32 at the edge of the substrate via an anisotropic conductive film 38. At this time, the display panel 31 and the flexible cable 33 are aligned so that the electrode terminals 32 and the conductive wires 34 face each other.

In this state, the heated pressure bonding head 3
5 is brought into contact with the flexible cable 33 and a predetermined pressure is applied to the display panel 31 and the flexible cable 3.
3 is thermocompression-bonded. The anisotropic conductive film 38 is a material that conducts only in the thickness direction when pressure and heat are applied.
2 and the conductive line 34 are electrically connected.

FIG. 7B is a plan view of the display panel 31 and the flexible cable 33 connected in this manner, as viewed from above.
4 is shown in a transparent state. As shown in this figure, the electrode terminals 32 of the display panel 31 and the conductive wires 34 of the flexible cable 33 are in a state of being electrically connected by a crimping portion 39 pressed by a crimping head 35.

On the other hand, the other end of the flexible cable 33 is connected to the circuit board 42 as shown in FIG. 6, and the electric signal output from the circuit board 42 is transmitted to the electrodes of the display panel 31. A desired display is performed.

[0013]

In the above-mentioned plasma display device, the pitch of display electrodes has been reduced in order to achieve high-definition display. ing. That is, as shown in FIG. 7B, when the crimping is performed in a state where the conductive foreign matter 40 is attached so as to straddle between the adjacent electrodes, the adjacent crimping portions 39 are electrically short-circuited. That situation occurs. The occurrence of an electrical short circuit causes display quality deterioration, such as a signal from a circuit board being input to a part other than a desired electrode to cause improper lighting.

In order to improve the brightness simultaneously with the high definition, ALiS which alternately applies a voltage every other line is used.
(Alternate Lighting of Surfaces Method) There is a method, but when this method is adopted, the above-mentioned short circuit between the electrodes causes a further obstacle. In other words, since a voltage is applied every other line, the voltage difference between adjacent electrodes increases, and if a short circuit occurs, the display panel made of a glass substrate and the drive circuit will be damaged.

In order to prevent such a short circuit due to the conductive foreign matter, it is conceivable that the glass substrate and the flexible cable are washed before the thermocompression bonding or the thermocompression bonding apparatus is frequently cleaned. Cannot be completely suppressed, and the number of manufacturing steps increases.

The present invention has been made to solve the above-mentioned problem, and provides a method of connecting electrode terminals of a flat display panel which can suppress occurrence of a short circuit between adjacent electrodes even when minute conductive foreign matter is present. With the goal.

[0017]

According to the present invention, there is provided a method for connecting an electrode terminal of a flat display panel to an electrode terminal group extending to a peripheral portion of a display panel with an anisotropic conductive film interposed therebetween.
After overlapping the flexible cable joints, heat and pressure are applied and crimped so that the electrical connection between the electrode terminal of the display panel and the flexible cable joint is staggered. is there.

As described above, in the present invention, the pressure between the electrode terminals of the display panel and the conductive wires of the flexible cable is crimped so that the conductive portions are arranged in a staggered manner, thereby increasing the distance between adjacent conductive portions. . Therefore, the probability of occurrence of short circuit due to foreign matter is extremely small.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the present invention is applied to a plasma display device will be described below in detail with reference to the drawings.

FIGS. 1 to 3 are views for explaining a first embodiment of the present invention. FIG. 1 is a sectional view for explaining a thermocompression bonding step according to the first embodiment. Is a perspective view thereof, and FIG. 3 is a view showing a thermocompression bonding state according to the first embodiment.

In the present embodiment, as shown in FIGS. 1 and 2, a pressure bonding head 5 having a staggered projection 6 is provided.
The crimping is performed using

First, a flat display panel (plasma display panel) is mounted on the stage 7 shown in FIG.
The display panel 1 is transported to the stage 7 by a transport roller, and is fixed to a predetermined position by being brought into contact with a positioning block or the like.

Next, the flexible cable 3 is arranged so as to face the electrode terminal 2 while being supported by a support mechanism (not shown). Flexible cable 3
As shown in FIG. 2, a base material 3a is coated with a coating material 3b, and the conductive wire 4 is covered with the coating material 3b except for a joint. The conductive wire 4 is shown only in FIG.
Then it is invisible.

At this time, an anisotropic conductive film 8 for electrically connecting the display panel 1 and the flexible cable 3 is interposed between the display panel 1 and the flexible cable 3. Or affixed in advance to the portion of the flexible cable 3 where the conductive wire 4 is exposed.

In this state, the flexible cable 3 is pressed from above by the pressure bonding head 5 to be heated.

Since the pressure bonding head 5 has a structure having a plurality of protrusions 6 projecting in a staggered manner as described above, only the portion of the anisotropic conductive film 8 which comes into contact with the protrusions 6 is thermocompression-bonded. As a result, the other portions are not thermocompressed and are not electrically conducted.

FIG. 3A is a sectional view showing a mechanism of thermocompression bonding, and FIG. 3B is a plan view showing a state after thermocompression bonding.

When pressure and heat are applied by the crimping head 5, as shown in FIG.
The portions of the anisotropic conductive film 8 corresponding to the protruding portions 6 are deformed, and the conductive filler 9 inside the anisotropic conductive film 8 is connected in the thickness direction. The conduction with the electrode terminal 2 of the display panel 1 is established.

The conductive filler 9 in the anisotropic conductive film 8
Is contained densely in the thickness direction and roughly in the in-plane direction, and a plurality of conductive fillers 9 are connected by a pressure applied in the thickness direction to form a conductive state. on the other hand,
In the in-plane direction, since the conductive fillers 9 are not close to each other, the conductive state does not occur even if some pressure is applied.

By such a mechanism, only the portion of the anisotropic conductive film 8 in contact with the staggered projections 6 of the pressure bonding head 5 is thermocompression-bonded and electrically connected.

FIG. 3B is a plan view for clarifying the thermocompression bonding portion. Although FIG. 3B is a plan view seen from above, the conductive wire 4 of the flexible cable 3 is shown in a see-through state.

As shown in FIG. 3B, the electrode terminal 2 of the display panel 1 and the conductive wire 4 of the flexible cable 3 are connected to the crimping portion 9 pressed by the protrusion 6 of the crimping head 5.
Are in a state of being electrically connected to each other. FIG.
As can be seen from (b), the crimping portions 9 are staggered corresponding to the staggered protrusions 6 of the crimping head 5.

In contrast to the prior art (see FIG. 7 (b)) in which the entire portion (surface) where the electrode terminal of the display panel and the conductive wire of the flexible cable overlap each other is thermocompression-bonded (the crimping portion is on the wire). In the present embodiment, the point-like crimping portion 9
Are arranged in a zigzag manner in the electrode terminal arrangement direction, and the electrode terminals 2 and the conductive wires 4 are insulated from each other.

Therefore, the distance between the adjacent crimping portions becomes longer, and even if conductive foreign matter 10 is present as shown in FIG. Become. This is particularly effective when performing the ALIS driving in which the voltage difference between adjacent electrodes is large.

Although not shown, the electrode terminals are led out to the entire periphery of the display panel 1, and the flexible cables 3 are connected in a predetermined number unit.

Next, a second embodiment of the present invention will be described with reference to FIG. FIG. 4 is a diagram showing a flexible cable according to a second embodiment of the present invention. FIG. 4 (a) is an exploded perspective view, and FIG. 4 (b) is a plan view.

The flexible cable 1 according to the present embodiment
As shown in FIG. 4 (a), reference numeral 3 denotes a coating material 13b having through holes 15 arranged in a staggered pattern on the entire surface of a base material 13a on which conductive wires 14 are formed. is there. The covering material 13b is made of a thin sheet-like insulating material, covers the conductive wires 14 formed on the base material 13a, and exposes a part thereof in a staggered manner.

That is, as is apparent from the plan view of FIG. 4B, in a state where the covering material 13b is covered on the base material 13a,
The conductive wires 14 are partially exposed from the staggered through holes 15.

Using such a flexible cable 13, pressure bonding with an electrode terminal of a display panel is performed as in the first embodiment. This is performed by applying pressure with a heated pressure bonding head in a state where an anisotropic conductive film is interposed between the display panel and the flexible cable, as in the method described in FIG. 1 in the first embodiment. .

In the case of the present embodiment, a staggered conductive portion can be formed by using a normal pressure bonding head having a flat contact portion, and short-circuiting due to foreign matter can be prevented.

Next, a third embodiment of the present invention will be described with reference to FIG. 5A and 5B show a display panel according to a third embodiment of the present invention. FIG. 5A is an exploded perspective view, and FIG. 5B is a plan view.

The display panel 21 according to the present embodiment has the structure shown in FIG.
As shown in FIG. 1A, an electrode sheet 22 is covered with an insulating sheet 23 having through holes 24 arranged in a staggered manner. By covering the insulating sheet 23, the electrode terminals 22 are exposed in a staggered manner.

Using the display panel 21 as described above, pressure bonding of the flexible cable to the conductive wire is performed as in the first embodiment. This is performed by applying pressure with a heated pressure bonding head in a state where an anisotropic conductive film is interposed between the display panel and the flexible cable, as in the method described in FIG. 1 in the first embodiment. .

Also in this embodiment, by using a normal pressure bonding head having a flat contacting portion, a staggered conductive portion can be formed, and short-circuiting due to foreign matter can be prevented.

In this embodiment, the structure is such that the insulating sheet 23 is covered. However, after the electrodes are formed on the display panel, the insulating layer may be formed by a thick film process so as to expose the electrode terminals 22 in a staggered manner. good.

In the second embodiment and the third embodiment,
Heating and pressurizing were performed with a normal crimping head in a state where the conductive wires of the flexible cable or the electrode terminals of the display panel were exposed in a zigzag pattern, but in addition to the conductive wires or electrode terminals exposed in a zigzag pattern, By using the pressure bonding head according to the first embodiment having the protruding portions having the shape, the conductive portions can be reliably formed in a staggered manner, and the effect of preventing short circuit is further enhanced.

[0047]

As described above, according to the present invention, the crimping is performed so that the conductive portions between the electrode terminals of the display panel and the conductive wires of the flexible cable are arranged in a staggered manner.
The distance between adjacent conductive parts becomes longer. Therefore, the probability of occurrence of short circuit due to foreign matter is extremely small.

Therefore, it is possible to prevent the display quality from deteriorating and the display panel and the drive circuit from being damaged.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view for explaining a crimping step according to a first embodiment of the present invention.

FIG. 2 is a perspective view for explaining a crimping step according to the first embodiment of the present invention.

FIG. 3 is a view showing a crimped state according to the first embodiment of the present invention.

FIG. 4 is a view showing a flexible cable according to a second embodiment of the present invention.

FIG. 5 is a diagram showing a display panel according to a third embodiment of the present invention.

FIG. 6 is a cross-sectional view and a plan view of the plasma display device.

FIG. 7 is a sectional view and a plan view for explaining a conventional technique.

[Explanation of symbols]

 1,21 display panel 2,22 electrode terminal 3,13 flexible cable 4,14 conductive wire 5 crimping head 6 protrusion 7 stage 8 anisotropic conductive film 9 conductive filler

Claims (4)

[Claims] 1. A method of connecting an electrode terminal group formed on a substrate of a flat display panel to a conductive wire group of a flexible cable for external take-out using an anisotropic conductive film, wherein the electrode terminal of the flat display panel is connected. An electrode terminal connecting method for a flat display panel, wherein the anisotropic conductive film is thermocompression-bonded so that electrical connection portions between the group and the conductive line group of the flexible cable are staggered in the electrode terminal arrangement direction. 2. A crimping head having protrusions arranged in a zigzag manner facing the electrode terminal group of the display panel and the conductive wire group of the flexible cable is prepared, and the protrusion is brought into contact with the flexible cable; 2. The electrode terminal connection of a flat display panel according to claim 1, wherein the electrical connection between the electrode terminal group of the display panel and the conductive wire group of the flexible cable is formed in a staggered manner by heating and pressing. Method. 3. A conductive wire exposed in a staggered manner after covering the conductive wire group of the flexible cable with an insulating coating material having a staggered through hole and exposing the conductive wire group in a staggered manner. The electrode terminal group of the display panel is overlapped with the group of electrode terminals of the display panel via the anisotropic conductive film, and the overlapping portion of the flexible cable is heated and pressurized by a crimping head. 2. The method for connecting electrode terminals of a flat display panel according to claim 1, wherein the electrical connection portion with the conductive line group is formed in a staggered manner. 4. An insulating film is formed on a portion of the electrode terminal group of the display panel so as to have a through hole that opens in a staggered manner, so that the electrode terminal group is exposed in a staggered manner. The flexible cable is superimposed on the electrode terminal group via an anisotropic conductive film, and the overlapping portion of the flexible cable is heated and pressurized by a crimping head, so that the conductive property of the electrode terminal group of the display panel and the flexible cable is reduced. 2. The method for connecting electrode terminals of a flat display panel according to claim 1, wherein the electrical connection portions with the line groups are formed in a staggered manner.