JP2000357854A - Fpc for electrode connection and display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an FPC(flexible printed circuit) which realizes easy repairing work as an FPC subjected to be ACF(anisotropic conducting film) connection with a driving circuit board or a display panel in a display device. SOLUTION: In an FPC 3 which is connected with a driving circuit board and a display panel of a display device by using an ACF, reinforcing films 32 formed of metal films are formed in regions on which wirings turning to FPC electrodes 31 are not formed. In the case that position deviation is generated when ACF connection is performed, and repairing work peeling the FPC 3 and regenerating the driving circuit board and a display panel is performed, since the reinforcing films 32 are formed on the FPC 3, polyimide films left on the driving circuit board and electrodes of the display panel can be reduced when the FPC 3 is peeled from the driving circuit board and the display panel. As a result, an ACF stuck on the driving circuit board and the electrodes of the display panel can be easily eliminated in the repairing work, and easy repairing work can be realized.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an anisotropic conductive film having thermosetting properties (hereinafter referred to as "ACF").
ive Film) ". FPC (Flexible Printed Circui) for electrode connection electrically connected to the substrate electrode via
t), and a display device using such an FPC for electrode connection, for example, a display panel and a display device of a display device used for image display such as television broadcast and information display such as a computer system. The present invention relates to an electrode connection FPC used for connection with a printed circuit board (hereinafter, referred to as a "drive circuit board") provided with the above drive circuit.

[0002]

2. Description of the Related Art Conventionally, when connecting electrodes of a display panel of a flat panel display such as a plasma display or a liquid crystal display device to electrodes of a driving circuit board, a flexible structure is provided between the display panel and the driving circuit board. An FPC for electrode connection in which wirings are formed on a film having the following is provided.

[0003] For connection between a display panel or a drive circuit board and an FPC, an electrode connection using an ACF (hereinafter, referred to as "ACF connection") is used to realize electrode connection at a fine pitch. FIGS. 14 to 16 show an example of a conventional ACF connection.
FIG. 9 is a diagram for explaining a state of connection with C.

FIG. 14 is an enlarged view showing the vicinity of an electrode (hereinafter, referred to as “substrate electrode”) 911 of a drive circuit substrate 901, and an ACF 912 attached to the substrate electrode 911 is shown by an imaginary line. FIG. 15 shows that the substrate electrode 911 has an ACF 91
2 is an enlarged view showing the vicinity of an electrode (hereinafter, referred to as an “FPC electrode”) 921 of a conventional FPC 902 connected via the second FPC 902. Note that the FPC electrode 921 is formed on the lower surface of the FPC 902 in FIG. FIG. 16 is a diagram showing a state where the substrate electrode 911 shown in FIG. 14 and the FPC electrode 921 shown in FIG. 15 are connected. In FIG. 16, the ACF 912 is omitted.

FIGS. 17 and 18 show an arrow 9A in FIG.
FIG. 17 is a cross-sectional view showing a cross section from the arrow 9B.
Shows a cross section at a position where the substrate electrode 911 and the FPC electrode 921 overlap, and FIG. 18 shows a cross section at a position where no electrode exists. In these figures, the cross sections are partially shown without parallel oblique lines.

As shown in FIG. 17, at the position where the electrodes exist, the substrate electrodes 91 are sequentially arranged from the drive circuit substrate 901 side.
1, the ACF 912 and the FPC electrode 921 are positioned so as to overlap. The ACF 912 is formed by dispersing conductive particles having a specific particle diameter in a binder component such as an epoxy resin having an excellent insulating property and an adhesive property to form a film. ACF on 901
912 and the FPC 902 in order,
Pressing is performed with a heat tool from the 02 side.

When pressing and heating are performed by the heat tool, the ACF 912 is temporarily softened and the substrate electrode 91 is softened.
1 and the FPC electrode 921, and the substrate electrode 911 and the FPC electrode 921.
The conductive particles are crushed between the PC electrode 921 and the two electrodes are electrically connected. After that, the ACF 912 is cured by heating, and the drive circuit board 901 and the FPC 902 are physically bonded.

On the other hand, as shown in FIG. 18, the base of the drive circuit board 901 and the FPC 902
Is physically bonded to the polyimide film, which is the main body, by ACF912.

The other end of the wiring of the FPC electrode 921 of the FPC 902 is connected to the display panel using the same ACF connection, thereby electrically connecting the drive circuit board 901 to the display panel.

By the method described above, the drive circuit board 9
Although the connection between the substrate electrode 911 and the FPC electrode 921 at a fine pitch has been performed conventionally, the drive circuit substrate 901 and the FPC electrode 921 are connected to each other.
02 may be shifted due to some trouble. At this time, since the drive circuit board 901 is expensive, it is generally collected (hereinafter, this collection work is referred to as “repair work”).

In a normal repair operation, first, an FPC 90
2 is peeled off from the drive circuit board 901, and the ACF 912 exposed on the drive circuit board 901 is immersed in a solvent such as toluene or acetone. Thereafter, the ACF 912 attached to the substrate electrode 911 is wiped off to remove the drive circuit substrate 9.
01 is reproduced.

[0012]

However, the FPC90
The polyimide film as the base material of No. 2 is generally 30 μm.
m, the thickness of which is only about m.
In the operation of peeling off the 902, a part of the polyimide film may remain on the drive circuit board 901 together with the ACF 912.

The polyimide film is used as the drive circuit board 901
Is left behind, the polyimide film covers the ACF 912 during the repair work, and the ACF 912
The removal of ACF 912 is very difficult.

In view of the above, the present invention has been made in view of the above-described problems, and an object of the present invention is to reduce the amount of polyimide film remaining when the FPC 902 is peeled off from the drive circuit board 901 in the repair work, thereby realizing easy repair work. It is an object.

[0015]

The first aspect of the present invention is an electrode connecting FPC which is electrically connected to a substrate electrode through an anisotropic conductive film having thermosetting properties. And a wiring formed on the film and connected to the substrate electrode via the anisotropic conductive film, and a reinforcing film formed in a non-wiring region on the film.

According to a second aspect of the present invention, in the electrode connecting FPC according to the first aspect, the reinforcing film is a metal film formed when the wiring is formed.

According to a third aspect of the present invention, in the electrode connecting FPC according to the first or second aspect, a notch is formed in the reinforcing film.

According to a fourth aspect of the present invention, in the electrode connecting FPC according to the third aspect, the notch is formed in a portion of the reinforcing film near an outer edge of the film.

A fifth aspect of the present invention is the electrode connecting FPC according to any one of the first to fourth aspects, wherein a hole is formed in the reinforcing film.

According to a sixth aspect of the present invention, there is provided a display device, comprising: a display panel which performs display based on a signal input through a substrate electrode of a panel substrate; and a drive circuit substrate which generates a signal to the display panel. And the display panel is electrically connected to the drive circuit board by being connected to at least one of the panel electrodes of the panel substrate or the drive circuit board via a thermosetting anisotropic conductive film. An electrode connecting FPC according to any one of claims 1 to 5.

The invention according to claim 7 is the display device according to claim 6, wherein the display panel is a plasma display panel.

[0022]

DESCRIPTION OF THE PREFERRED EMBODIMENTS First Embodiment 1 and 2 are a front view and a rear view, respectively, showing a part of an internal configuration of a plasma display which is a display device 1 according to the present invention. As shown in FIGS. 1 and 2, the display device 1 includes a display panel having a structure in which a front panel 11a and a rear panel 11b, which are panel substrates, are stacked, and a drive circuit board 2 for supplying control signals and drive power to the display panel. And an electrode connection FPC 3 for electrically connecting the electrodes of the front panel 11a or the rear panel 11b to the electrodes of the drive circuit board 2.

The front panel 11a and the rear panel 11
The connection between the electrode b and the FPC 3 is performed by an ACF connection via an ACF 4 (shown by hatching in FIGS. 1 and 2) which is a thermosetting anisotropic conductive film. The connection between the board electrode of the drive circuit board 2 and the FPC 3 is also ACF4.
Via the ACF connection. Thus, the display panel is electrically connected to the drive circuit board 2 via the FPC 3, and the display panel is driven by a signal from the drive circuit board 2.

1 and 2, the drive circuit board 2
Are arranged around the display panel, but when the internal structure of the display device 1 shown in FIGS. 1 and 2 is housed in the casing, the drive circuit board 2 utilizing the flexibility of the FPC 3 is used.
Are arranged on the rear panel 11b side.

FIG. 3 is a plan view showing a state near the substrate electrode 21 of the drive circuit substrate 2 in a state where the FPC 3 is not connected. In FIG. 3, the state in which the ACF 4 is attached is shown by imaginary lines. The substrate electrode 21 is the drive circuit substrate 2
Of the wiring 22 extending from the circuit of FIG.
This is a part to be connected to the PC 3 by ACF. Although the actual substrate electrodes 21 are formed at a fine pitch, they are somewhat simplified in FIG. The same applies to corresponding parts in the following figures.

FIG. 4 is a view showing the vicinity of the FPC electrode 31 of the FPC 3. Wiring for electrically connecting the drive circuit board 2 and the display panel is formed on the FPC 3 on the polyimide film, and the vicinity of the tip of the wiring is an FPC electrode 31 for performing ACF connection. FIG.
The FPC electrode 31 is formed on the lower surface of the film.

A reinforcing film 32 is formed on a region of the lower surface of the film where the FPC electrode 31 is not formed. As the reinforcing film 32, for example, one formed as a metal film pattern at the same time when a wiring pattern including the FPC electrode 31 is formed on the FPC 3 is used. In FIG. 4, in order to clearly show the reinforcing film 32, a region where the reinforcing film 32 is formed is indicated by parallel oblique lines (the same applies to the following drawings).

FIG. 5 shows that the drive circuit board 2 and the FPC 3 are AC-connected.
It is a figure which shows the state which carried out ACF connection using F4 (illustration omitted in FIG. 5, and FIG. 9, FIG. 12). That is, FIG. 3 is a view showing a state in which after the ACF 4 is attached to the substrate electrode 21 of the drive circuit board 2, the substrate electrode 21 and the FPC electrode 31 are aligned, and further, heat-pressing is performed from the FPC 3 side using a heat tool. FIG. 6 is a cross-sectional view from the direction indicated by arrow 1A in FIG.
FIG. 3 is a diagram showing a cross section at a position where an FPC electrode 31 exists. FIG. 7 is a cross-sectional view from the direction indicated by the arrow 1B in FIG. 5, and a cross-sectional view at a position where the substrate electrode 21 and the FPC electrode 31 are not present.

In FIG. 6, the substrate base 23, the substrate electrode 21, the ACF 4, the FPC electrode 3
1 and the polyimide film 33 are laminated, and the conductive particles contained in the ACF 4 are crushed between the substrate electrode 21 and the FPC electrode 31 by pressing with a heat tool, and these electrodes are electrically connected. You. Further, the substrate electrode 21 and the FPC electrode 31 are physically connected by the adhesive action of the ACF 4.

On the other hand, as shown in FIG.
In a region where the PC electrode 31 is not located, the base 23, the ACF 4, the reinforcing film 32, and the polyimide film 33 are sequentially stacked from the drive circuit board 2 side. Therefore, the base 23 and the polyimide film 33 are
Instead of being connected by F4, the base 23 and the reinforcing film 3
2 are bonded by the bonding action of ACF4.

The FPC 3 according to the first embodiment and the display device 1 using the FPC 3 have been described above. As shown in FIG. 4, the FPC 3 is provided with a reinforcing film 32 in a non-wiring region on a polyimide film 33. When the FPC 3 is peeled off from the drive circuit board 2 in the repair work, the polyimide film 3
3 hardly remains.

That is, when the reinforcing film 32 is not present, a part of the polyimide film as thin as several tens of μm may remain together with the ACF. Metal reinforcing film 3
2, polyimide film 33 and A
Since the adhesive area with CF4 can be reduced and the apparent strength of the polyimide film 33 is improved by the reinforcing film 32, the polyimide film 33 is removed together with the reinforcing film 32 when the FPC 3 is peeled from the drive circuit board 2. Peeled off. Thereby, it is possible to suppress the polyimide film 33 from remaining on the substrate electrode 21 during the repair work.

As a result, the work of removing the ACF 4 on the substrate electrode 21 can be easily performed, and the cost of the repair work can be reduced.

By forming a pattern for the reinforcing film 32 around the wiring pattern when forming the wiring pattern of the FPC 3 as the reinforcing film 32, the cost required for forming the reinforcing film 32 can be reduced.

Second Embodiment FIG. 8 is a diagram illustrating an FPC 3 according to the second embodiment. The FPC 3 according to the second embodiment is different from the FPC 3 according to the first embodiment only in that a notch 321 is formed on the outer peripheral portion of the reinforcing film 32. In the following description, the same members as those in the first embodiment are denoted by the same reference numerals as those in the first embodiment.

FIG. 9 is a view corresponding to FIG. 5 in the first embodiment, and shows a state in which the drive circuit board 2 and the FPC 3 according to the second embodiment are connected. That is, A is applied to the substrate electrode 21 of the drive circuit substrate 2 shown in FIG.
After the CF4 is attached and the FPC electrodes 31 of the FPC 3 are aligned with the substrate electrodes 21, the drive circuit board 2 and the FPC 3 are heat-pressed using a heat tool.

FIG. 10 is a cross-sectional view as viewed from the arrow 2B shown in FIG. 9, and shows a cross section at a position where the cutout portion 321 of the reinforcing film 32 is formed. The state of the cross section at the position where the electrode exists is the same as that in FIG. As shown in FIG.
At the portion where the notch 321 is not formed, the base 23, the ACF4, the reinforcing film 32, and the polyimide film 33 are laminated in this order from the drive circuit board 2 side, and at the portion where the notch 321 is formed, Drive circuit board 2
The base 23, the ACF4, and the polyimide film 33 are sequentially laminated from the side.

By forming the notch 321 in the reinforcing film 32 of the FPC 3 as shown in FIG. 8, there is an effect that the adhesive strength of the FPC 3 to the drive circuit board 2 can be increased. That is, since the area where the cutout portion 321 is formed is in a state where irregularities are formed on the surface of the FPC 3, the resin temporarily softened by heat during the ACF connection flows into the irregularities. After that, by further applying heat, the resin flowing into the unevenness is hardened.
The bonding area between the drive circuit board 2 and the FPC 3 increases due to the so-called anchor effect (also referred to as “zipper effect”). In addition,
The fact that the polyimide film has a higher adhesive force by the ACF than the metal film also contributes to the improvement of the adhesive strength of the FPC 3 by the cutout portion 321.

When the reinforcing film 32 is formed in the same step as the formation of the wiring pattern on the FPC 3, gold plating for stabilizing the quality of the electrode is applied to the reinforcing film 32 as well as the wiring pattern. Since the gold-plated reinforcing film 32 has a lower adhesive strength due to the ACF4 than the polyimide film 33, there is a possibility that the adhesive strength cannot be maintained depending on the bonding conditions. Therefore, in the FPC 3 according to the second embodiment, the notch 321 is formed in the outer peripheral portion of the reinforcing film 32, so that the repair work by the reinforcing film 32 can be easily performed and the drive circuit board 2 and the FPC 3 can be connected to each other. It is realized that the adhesive strength between them is kept high and stably.

As shown in FIG. 8, by forming a large number of notches 321 near the outer edge of the FPC 3 (that is, the polyimide film 33), the FPC 3 can be effectively prevented from peeling from the outer edge. be able to.

Third Embodiment FIG. 11 is a diagram illustrating an FPC 3 according to the third embodiment. The FPC 3 according to the third embodiment differs from the FPC 3 according to the first embodiment only in that a hole 322 is formed in the reinforcing film 32. In the following description, the same members as those in the first embodiment are denoted by the same reference numerals as those in the first embodiment.

FIG. 12 is a view corresponding to FIG. 5 in the first embodiment, and shows a state in which the drive circuit board 2 and the FPC 3 according to the third embodiment are connected. That is, after the ACF 4 is attached to the substrate electrode 21 of the drive circuit board 2 shown in FIG. 3 and the FPC electrode 31 of the FPC 3 is aligned with the board electrode 21, the drive circuit board 2 and the FPC 3 are Indicates a state in which thermocompression bonding is performed.

FIG. 13 is a cross-sectional view when viewed from the arrow 3B shown in FIG. 12, and shows a cross section at a position where the hole 322 of the reinforcing film 32 is formed. The state of the cross section at the position where the electrode exists is the same as that in FIG. As shown in FIG. 13, at a portion where the hole 322 is not formed, the base 23, the ACF 4, the reinforcing film 32, and the polyimide film 33 are laminated in this order from the drive circuit board 2 side. The portion where the portion 322 is formed has a structure in which the base 23, the ACF 4, and the polyimide film 33 are sequentially stacked from the drive circuit board 2 side.

As shown in FIG. 11, the reinforcing film 32 of the FPC 3
A hole 322 is formed in the drive circuit board 2 like the FPC 3 according to the second embodiment.
The effect that the adhesive strength of C3 can be increased is produced. That is, the area where the hole 322 is formed is the FPC3
ACF is formed on the surface of the ACF.
4 and the FPC 3 increase, and the bonding strength between the drive circuit board 2 and the FPC 3 increases due to the so-called anchor effect.

As a result, similarly to the second embodiment, the FPC 3 according to the third embodiment realizes an easy repair work by the reinforcing film 32, and simultaneously connects the drive circuit board 2 to the FPC.
It is realized that the adhesive strength with the PC 3 is maintained stably high.

Modified example. Although the embodiment according to the present invention has been described above, the present invention is not limited to the above embodiment, and various modifications are possible.

For example, in the above embodiment, the reinforcing film 32
As described above, a metal film that can be formed in the step of forming the wiring pattern of the FPC 3 is used, but a reinforcing film made of another material may be used.

In the second embodiment, the notch 321 is formed on the outer periphery of the reinforcing film 32. However, the position where the notch 321 is formed is limited to that shown in FIG. However, it may be formed at any position. Further, the shape and size of the hole 322 in the third embodiment may be arbitrarily designed, and both the notch 321 and the hole 322 may be formed. The reinforcing film 32 does not need to be formed so as to extend over the entire non-wiring region, but may be partially (particularly, ACF).
However, the effect of reducing the remaining film can be achieved even if it is formed only in the region where the polyimide film is adhered and the polyimide film is likely to remain.

In the above embodiment, the ACF connection between the substrate electrode 21 of the drive circuit board 2 and the FPC electrode 31 of the FPC 3 has been described as an example. The present invention can also be used for ACF connection between a substrate electrode of a panel substrate constituting a display panel, and also in this case, an easy repair operation can be realized.

In the above embodiment, a PDP (Plasma Display Panel) is taken as an example of the display panel.
A in a display panel of another display device such as a liquid crystal display device
ACF used for CF connection and other than display device
It can also be used for connection. The materials of the film and the wiring constituting the FPC 3 are not limited to those in the above embodiment, and the present invention can be used as long as the material has the same properties.

[0051]

According to the first and sixth aspects of the present invention, the film remaining on the substrate electrode during the repair operation can be reduced by the reinforcing film, and the easy repair operation can be realized.

According to the second aspect of the present invention, the cost required for forming the reinforcing film can be reduced.

According to the third and fifth aspects of the present invention, the adhesive strength of the electrode connecting FPC to the substrate electrode can be kept high while realizing an easy repair work using the reinforcing film.

According to the fourth aspect of the present invention, the electrode connecting F
Peeling from the outer edge of the PC can be effectively prevented.

According to the seventh aspect of the invention, an easy repair operation can be realized when manufacturing a display device having a plasma display panel.

[Brief description of the drawings]

FIG. 1 is a front view showing an internal configuration of a plasma display which is a display device according to the present invention.

FIG. 2 is a rear view of the internal configuration of the plasma display shown in FIG.

FIG. 3 is a plan view showing a state near a substrate electrode of a drive circuit substrate.

FIG. 4 is a plan view showing the vicinity of an FPC electrode of the FPC according to the first embodiment.

FIG. 5 illustrates a method of connecting a drive circuit board and an FPC using an ACF.
It is a figure showing the state where CF connection was performed.

FIG. 6 is a cross-sectional view from the direction indicated by arrow 1A in FIG.

FIG. 7 is a cross-sectional view from the direction indicated by arrow 1B in FIG.

FIG. 8 is a plan view showing the vicinity of an FPC electrode of an FPC according to a second embodiment.

FIG. 9 illustrates a method of connecting a drive circuit board and an FPC to each other by using an ACF.
It is a figure showing the state where CF connection was performed.

FIG. 10 is a cross-sectional view from the direction indicated by arrow 2B in FIG.

FIG. 11 is a plan view showing the vicinity of an FPC electrode of an FPC according to a third embodiment.

FIG. 12 is a diagram illustrating a state in which a drive circuit board and an FPC are connected to each other by ACF using an ACF.

FIG. 13 is a cross-sectional view from the direction indicated by arrow 3B in FIG.

FIG. 14 is a plan view showing a state near a substrate electrode of a drive circuit substrate.

FIG. 15 is a plan view showing the vicinity of an FPC electrode of a conventional FPC.

FIG. 16 is a diagram illustrating a state in which a drive circuit board and a conventional FPC are ACF-connected using an ACF.

FIG. 17 is a cross-sectional view from the direction indicated by arrow 9A in FIG.

FIG. 18 is a cross-sectional view from the direction indicated by arrow 9B in FIG.

[Explanation of symbols]

1 display device, 2 drive circuit board, 3 FPC, 4A
CF, 11a front panel, 11b rear panel, 21
Substrate electrode, 31 FPC electrode, 32 Reinforcement film, 33
Polyimide film, 321 notch, 322 hole.

 ──────────────────────────────────────────────────の Continuing on the front page (72) Inventor Hiroshi Seki 2-3-2 Marunouchi, Chiyoda-ku, Tokyo Mitsubishi Electric Corporation F-term (reference) 2H092 GA48 GA49 GA50 GA55 GA57 HA25 HA28 JB74 MA32 MA35 MA37 MA49 NA25 NA29 NA30 5E338 AA12 AA16 BB72 CC01 CD32 EE26 5E344 AA02 BB02 BB04 BB10 CC03 CD04 DD10 EE21 5G435 AA00 AA17 BB06 EE33 EE34 EE37 EE42 EE47 KK05

Claims (7)

[Claims] An FPC for electrode connection electrically connected to a substrate electrode via an anisotropic conductive film having thermosetting properties, comprising: a flexible film; and a flexible film formed on the film. An electrode connection FPC, comprising: a wiring connected to the substrate electrode via the anisotropic conductive film; and a reinforcing film formed in a non-wiring region on the film. 2. The FPC for electrode connection according to claim 1, wherein the reinforcing film is a metal film formed at the time of forming the wiring. 3. The electrode connection F according to claim 1 or 2,
An electrode-connecting FPC, wherein a notch is formed in the reinforcing film. 4. The electrode connecting FPC according to claim 3, wherein the notch is formed in a portion of the reinforcing film near an outer edge of the film.
C. 5. The electrode connecting FPC according to claim 1, wherein a hole is formed in the reinforcing film. 6. A display device, comprising: a display panel that performs display based on a signal input through a substrate electrode of a panel substrate; a drive circuit substrate that generates a signal to the display panel; The display panel is electrically connected to the drive circuit board by being connected to at least one of substrate electrodes of the drive circuit board via a thermosetting anisotropic conductive film. 5. A display device, comprising: the electrode connection FPC according to any one of 5. 7. The display device according to claim 6, wherein the display panel is a plasma display panel.