KR100939607B1 - Connecting structure and connecting method of circuit - Google Patents

Abstract

In the connection structure of the plasma display panel (PDP) and the flexible printed circuit board (FPC substrate), the purpose of preventing migration of the Ag electrode of the PDP, and the wiring terminal of the electrode of the PDP and the FPC substrate is anisotropic conductive adhesive (ACF) In the method of connecting by heating and pressing with a crimping tool, the width of the crimping tool 40 is a, the overlapping width of the electrode 3 and the wiring terminal 12 is b, and the width of the crimping tool from the FPC board side edge of the crimping tool. The distance to the electrode end c, the distance from the FPC board side edge of the crimping tool to the end of the coverlay 13 of the FPC board d, the width of the ACF 20 after connection e, the PDP of the crimping tool When the distance of the edge part 1 of the said wiring terminal from the side edge is f, and the average particle diameter of the electroconductive particle contained in the said ACF is m,

a ≥ e ≥ b

c ≥ 0

f ≥ 0

d: m = 20: 1 to 200: 1

Placed in the positional relationship of and pressurized by heating.

Plasma Display Panel, Crimping Tool, Electrode, Wiring Terminal, Anisotropic Conductive Adhesive, Coverlay

Description

Connection structure and connection method of circuit {CONNECTING STRUCTURE AND CONNECTING METHOD OF CIRCUIT}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technique for preventing migration of electrodes, particularly Ag electrodes, of a plasma display panel in a connection structure between a plasma display panel and a flexible printed circuit board.

As shown in FIG. 8, the connection structure of the electrodes of the plasma display panel generally includes the electrodes 3 on the glass substrate 2 of the plasma display panel 1 and the wiring terminals 12 of the flexible printed circuit board 10. ) Is connected by heat-pressing with a crimping tool via the anisotropic conductive adhesive 20.

Here, the electrode 3 of the plasma display panel 1 is formed of Cr / Cu / Cr, Al, Ag or the like, but most of them are formed using Ag paste in order to reduce cost.

On the other hand, as for the flexible printed circuit board 10, the wiring which consists of Cu etc. is formed on the flexible substrate 11 which consists of insulating sheets, such as PET, and the coverlay 13 was laminated | stacked on it, and a wiring terminal Gold plating is usually given to the surface of (12).

After connecting the electrode 3 of the plasma display panel 1 and the wiring terminal 12 of the flexible printed circuit board 10 by heat and pressure through the anisotropic conductive adhesive 20, the connection part is a silicone resin etc. It is sealed by the sealing resin 31 and 32 which consist of these.

By the way, a potential difference of 50 V or more occurs between the electrodes adjacent to the plasma display panel 1. In addition, since the pitch of the electrode 3 of the plasma display panel 1 is small, for example, about 0.2 mm, when the polarities between adjacent electrodes 3 are different, the electric field strength generated between the electrodes 3 becomes large. . For this reason, when the electrode 3 is exposed to moisture or moisture due to the use environment, the metal forming the electrode 3 is ionized, moves from one electrode to the other electrode, and the metal precipitates there. This may occur and a short circuit may occur between the electrodes 3. In particular, although Ag is widely used as the forming metal of the electrode 3, Ag easily migrates. In addition, in the manufacturing process of the plasma display panel 1, although halogen ions may enter an electrode from the compound contained in a board | substrate material, in this case, migration will occur more easily. Therefore, in order to prevent the electrode 3 from being exposed to moisture or moisture, the connection portion between the electrode 3 of the plasma display panel 1 and the wiring terminal 12 of the flexible printed circuit board 10 is sealed with a resin 31. , 32).

However, only the sealing of the connection part by the sealing resin 31 and 32 cannot fully prevent migration. On the other hand, although it is proposed to form a barrier between wirings with resin containing a cation exchanger and an anion exchanger (patent document 1), a connection process becomes complicated and a cost rises.

Patent Document 1: Japanese Patent Application Laid-Open No. 2000-183470

SUMMARY OF THE INVENTION An object of the present invention is to easily prevent migration of electrodes of a plasma display panel, particularly Ag electrodes, and to improve wiring reliability in a connection structure between a plasma display panel and a flexible printed board.

MEANS TO SOLVE THE PROBLEM This inventor connects the electrode of a plasma display panel and the wiring terminal of a flexible printed circuit board by heating and pressurizing it with a crimping tool through an anisotropic conductive adhesive, and the edge of a crimping tool, the electrode of a plasma display panel, and the wiring terminal of a flexible printed circuit board. It has been found that by placing in a specific positional relationship, the occurrence of migration can be significantly suppressed.

That is, the present invention relates to a circuit connecting method for connecting the electrode of the plasma display panel and the wiring terminal of the flexible printed circuit board by heating and pressing it with a crimping tool through an anisotropic conductive adhesive, wherein the width of the crimping tool is a B, the overlapping width of the electrode and the wiring terminal of the flexible printed circuit board, b, the distance from the flexible printed board side edge of the crimping tool to the electrode end of the plasma display panel, c, the flexible print from the flexible printed board side edge of the crimping tool. The distance to the end of the coverlay of the board | substrate d, the width of the anisotropically conductive adhesive agent after connection, e, and the distance from the plasma display panel side edge of a crimping tool to the wiring terminal end part of a flexible printed circuit board are included in the anisotropically conductive adhesive agent. When the average particle diameter of the conductive particles to be m is

a ≥ e ≥ b

c ≥ 0

f ≥ 0

d: m = 20: 1 to 200: 1

In order to satisfy this problem, there is provided a circuit connecting method characterized by disposing a plasma display panel, a flexible printed circuit board, and a crimping tool.

In addition, the present invention is a connection structure of a circuit obtained as described above, in a connection structure of a circuit in which an electrode of a plasma display panel and a wiring terminal of a flexible printed board are heated and pressed by an anisotropic conductive adhesive. The overlapping width of the electrode and the wiring terminal of the flexible printed circuit board b, the width of the anisotropic conductive adhesive e, the distance between the end of the coverlay of the flexible printed circuit board and the electrode end of the plasma display panel, contained in the anisotropic conductive adhesive When the average particle diameter of the conductive particles to be set to m,

e ≥ b

g: m = 20: 1 to 200: 1

This provides a connection structure of a circuit which is satisfied.

According to the present invention, it is possible to prevent migration of electrodes of the plasma display panel, particularly Ag electrodes, in the connection structure between the plasma display panel and the flexible printed circuit board using a conventional crimping tool, and to improve the reliability of the wiring.

1 is a cross-sectional view showing the arrangement of a plasma display panel, a flexible printed circuit board, and a crimping tool in the method of the present invention.

Fig. 2 is a sectional view showing the arrangement of the plasma display panel, the flexible printed circuit board and the crimping tool in the method of the present invention.

3 is a cross-sectional view showing the arrangement of the plasma display panel, the flexible printed circuit board, and the crimping tool in the comparative example.

4 is a cross-sectional view showing the arrangement of the plasma display panel, the flexible printed circuit board, and the crimping tool in the comparative example.

Fig. 5 is a sectional view showing the arrangement of the plasma display panel, the flexible printed circuit board, and the crimping tool in the comparative example.

6 is a cross-sectional view showing the arrangement of the plasma display panel, the flexible printed circuit board, and the crimping tool in the comparative example.

7 is a cross-sectional view showing the arrangement of the plasma display panel, the flexible printed circuit board, and the crimping tool in the comparative example.

Fig. 8 is a perspective view (Fig. 8 (a)) and an x-x cross-sectional view (Fig. 8 (b)) showing the connection structure of the electrodes of the plasma display.

<Description of the code>

1: plasma display panel

2: glass substrate

3: electrode (Ag electrode) of the plasma display panel

10: flexible printed circuit board

11: flexible substrate

12: wiring terminal

13: coverlay

20: anisotropic conductive adhesive

31, 32: sealing resin

40: Crimping Tool

EMBODIMENT OF THE INVENTION Hereinafter, this invention is demonstrated in detail, referring drawings. In addition, in each figure, the same code | symbol has shown the component of the same or equivalent structure.

1 shows a crimping tool (when connecting the plasma display panel 1 and the flexible printed circuit board 10 by heating and pressing the crimping tool 40 through the anisotropic conductive adhesive 20 according to one embodiment of the present invention). 40 is a cross-sectional view showing the positional relationship between the plasma display panel 1 and the flexible printed circuit board 10.

The plasma display panel 1 has the glass substrates 2 and 2 'opposed to each other with a discharge space, and an electrode 3 formed by printing Ag paste is provided on the lower glass substrate 2. The electrode 3 has a large number of electrode wires having a width of 0.05 to 1.0 mm at a pitch of 0.1 to 20 mm, and is exposed at the connecting portion of the flexible printed circuit board 10.

On the other hand, the flexible printed circuit board 10 laminates Cu wiring (thickness 5-40 micrometers) on the flexible substrate (thickness 10-100 micrometers) 11 which consists of polyimides etc., and is made with polyimide etc. on it. The coverlay (10-50 micrometers in thickness) 13 which consists of these is provided, and the wiring terminal 12 of this Cu wiring is exposed in the connection part of the plasma display panel 1. As shown in FIG.

The anisotropic conductive adhesive 20 disperse | distributes electroconductive particle of particle size 0.1-15 micrometers, Preferably 1-10 micrometers with an insulating adhesive, and shape | molds to the film form of thickness 10-50 micrometers. By heat-pressing, this anisotropic conductive adhesive 20 expresses electroconductivity only in the thickness direction, and does not show electroconductivity in the other direction. As the anisotropic conductive adhesive 20, a paint-type thing may be used, and the coating film may use what expresses anisotropic conductivity by heating and pressing.

As the crimping tool 40, what can heat-press pressurized object to a temperature of 150-200 degreeC, and a pressure of 2-10 Mpa is used.

In the method of the present invention shown in Fig. 1, the width of the crimping tool 40 is a, and the width of the electrode 3 of the plasma display panel 1 and the width of the wiring terminal 12 of the flexible printed circuit board 10 are overlapped. B, the distance from the flexible printed circuit board 10 side edge of the crimping tool 40 to the electrode end of the plasma display panel 1 (that is, the edge of the flexible printed circuit board 10 side of the crimping tool 40). Distance between the edge and the electrode end of the plasma display panel 1 when the direction from the center to the center of the plasma display panel 1 is positive; c, the flexible printed circuit board 10 of the crimping tool 40. Distance from the side edge to the end of the coverlay 13 of the flexible printed circuit board 10 (i.e. from the edge of the flexible printed circuit board 10 side of the crimping tool 40 to the center of the flexible printed circuit board 10). Distance between the edge and the end of the coverlay 13 when the direction of plus is positive, d, The width of the anisotropic conductive adhesive afterwards is e, and the distance from the edge of the plasma display panel 1 side of the crimping tool 40 to the end of the wiring terminal 12 of the flexible printed circuit board 10 (that is, of the crimping tool 40). Distance between the edge and the end of the wiring terminal 12 when the direction from the edge on the side of the plasma display panel 1 to the center of the flexible printed circuit board is positive; When the average particle diameter of the conductive particles to be set to m,

a ≥ e ≥ b

c ≥ 0

f ≥ 0

d: m = 20: 1 to 200: 1

The plasma display panel 1, the flexible printed circuit board 10, and the crimping tool 40 are disposed so as to be satisfied.

By setting e ≥ b, the exposed portion of the Ag electrode 3 in the connecting portion is reduced, and by setting a ≥ e, the anisotropic conductive adhesive 20 is sufficiently adhered to the entire connecting portion by the crimping tool 40. In addition, although FIG. 1 shows the form in which the anisotropically conductive adhesive 20 after connection did not reach the coverlay 13 of the flexible printed circuit board 10, as shown in FIG. 2, the anisotropically conductive adhesive 20 after connection is shown. ) May not only cover the Ag electrode of the connecting portion, but also partially cover the coverlay 13 of the flexible printed circuit board 10.

Moreover, in this invention, since the whole connection part can be crimped | bonded by the crimping tool 40 by setting it as c≥0 and f≥0, it becomes possible to fully adhere the anisotropic conductive adhesive 20 to the whole connection part.

Moreover, between the Ag electrode 3 and the wiring terminal 12, the anisotropic conductive adhesive 20 is heat-pressed by the crimping tool 40, and the electroconductive particle and insulating adhesive in the anisotropic conductive adhesive 20 are circumferentially connected to the connection part. When flowing, if d is small, the flow of the conductive particles may be disturbed by the coverlay 13 of the flexible printed circuit board 10, and the conductive particles gather on the coverlay 13 side of the connecting portion, where the short Happens easily. In addition, when heat-pressurizing with the crimping tool 40, the non-compression | bonding part of the flexible printed circuit board 10 may bend, and also in this case, electroconductive particle collects on the coverlay 13 side of a connection part, and a shot thereon Happens easily. In the present invention, on the other hand, d: m = 20: 1 to 200: 1, by making d sufficiently wide, such a short can be prevented.

In this way, in the connection structure of the heat-compression-bonded plasma display panel 1 and the flexible printed circuit board 10, it becomes e≥ b, Since the connection part is covered by the insulating adhesive of the anisotropically conductive adhesive firmly bonded, Ag This can prevent migration as the electrode is exposed to moisture or moisture. In addition, when the distance between the end of the coverlay 13 of the flexible printed circuit board 10 and the end of the electrode 3 of the plasma display panel 1 is set to g, g: m = 20: 1 to 200: 1, the connection part does not produce the short by electroconductive particle in an anisotropically conductive adhesive agent.

In the present invention, in order to further prevent the occurrence of migration of the electrode 3 of the plasma display panel 1, as in the conventional example shown in FIG. You may seal the center part side of a board | substrate with sealing resin 31 and 32, respectively.

<Example>

<1st Example, 1st-5th Comparative Example>

The glass substrate of the plasma display 1 in the arrangement shown in FIG. 1, using an anisotropic conductive adhesive (Sony Chemical Co., CP7642K, average particle diameter of conductive particles: 6 µm) generally used for connecting electrodes of the plasma display panel. (2) (Ag electrode, 10 micrometers in thickness, 0.2 mm in pitch, 100 lines) on the electrode 3 (made by Asahi Glass Co., Ltd., PD200), and the wiring terminal 12 of the flexible printed circuit board 10 (thickness 35) Ni-plated and Au-plated on a Cu wire of μm, pitch 0.2 mm (L / S = 1/1)] by heat crimp using a crimping tool (170 ° C, 3 MPa, 20 sec, cushioning material: 0.2 Mm silicon rubber).

Then, DC 100V application aging was performed for 500 hours in the environment of 60 degreeC and 95% RH, and the time until short-circuit was determined by the case where the connection resistance between adjacent terminals is less than 10 ⁶ ohms, and measured.

In addition, except that the above-mentioned distances a, b, c, d, e, f and d / m are as shown in Table 1, the plasma display panel and the flexible printed circuit board were similarly connected to investigate the occurrence of shortage due to aging. It was.

The results are shown in Table 1. In addition, the arrangement of the first to fifth comparative examples shown in Table 1 is shown in Figs.

Second Embodiment

Except using the thing prepared as follows as an anisotropically conductive adhesive agent, the plasma display panel and the flexible printed circuit board were connected like Example 1, and generation | occurrence | production of the short by aging was investigated. The results are shown in Table 1.

Method for preparing an anisotropic conductive adhesive: Mixing 40 parts by weight of phenoxy resin (Tosei Kasei, YP50), 30 parts by weight of epoxy resin (Emulsion Shell, EP828) and 30 parts by weight of latent curing agent (Asahi Kasei, HX3741) as an insulating adhesive What prepared was prepared and disperse | distributed 5 weight part of electroconductive particle (average particle diameter: 2.5 micrometers) (Sekisui Fine Chemical Co., Ltd., Micro Pearl Au 210) which nickel / plated the vinylidene benzone particle to 100 weight part of this insulating adhesive materials is anisotropic conductive It was made into an adhesive agent.

Third Embodiment

As the anisotropic conductive adhesive, 5 parts by weight of conductive particles (average particle size 10 µm) (Japan Chemical Co., Ltd.) having a nickel plating layer formed on the surface of the benzogamine resin particles were dispersed with respect to 100 parts by weight of the insulating adhesive of the second embodiment. Except for using the same, as in the first embodiment, the plasma display panel and the flexible printed circuit board were connected to investigate the occurrence of a short due to aging. The results are shown in Table 1.

TABLE 1

(Unit: mm)

a b c d d / m e f Time to short First embodiment 4 3 0.5 0.2 33.33 3.5 0.5 500 hr or more Second embodiment 4 3 0.5 0.2 80 3.5 0.5 500 hr or more Third embodiment 4 3 0.5 0.2 20 3.5 0.5 500 hr or more Comparative Example 1 2 3 -0.5 1.5 250 2.5 -0.5 60 hr 2nd comparative example 4 3 -0.5 0.2 33.33 3.2 1.5 70 hr Third Comparative Example 4 3 2 0.2 33.33 3.2 -One 70 hr Fourth Comparative Example 4 3 0.5 0.2 33.33 2.7 0.5 50 hr 5th comparative example 4 3 0.5 0.05 8.33 3.5 0.5 0 hr

From Table 1, according to the first to third embodiments of the present invention, even after 500 hours of aging, the resistance between adjacent terminals exceeded 10 ⁶ Ω and the wiring reliability was good. Occurred. In particular, in the fifth comparative example in which the distance d was 0.05 mm and the d / m was less than 20, the conductive particles of the anisotropic conductive adhesive were connected on the flexible printed circuit board 1 side of the connecting portion, and a short occurred immediately.

This invention is useful when connecting the electrode of a plasma display panel and the wiring terminal of a flexible printed circuit board using an anisotropic conductive adhesive agent.

Claims (3)

In the connection method of the circuit which connects the electrode of a plasma display panel and the wiring terminal of a flexible printed circuit board by heat-pressing with a crimping tool via an anisotropic conductive adhesive, The width of the crimping tool a, the overlap width of the electrode of the plasma display panel and the wiring terminal of the flexible printed circuit board b, the distance from the flexible printed board side edge of the crimping tool to the electrode end of the plasma display panel c, the crimping tool The distance from the flexible printed circuit board side edge of the flexible printed circuit board to the end of the coverlay of the flexible printed circuit board (plus direction from the crimping tool edge to the flexible printed circuit board center part) d, and the width of the anisotropic conductive adhesive after connection e, when the distance from the plasma display panel side edge of a crimping tool to the wiring terminal end part of a flexible printed circuit board is f, and the average particle diameter of the electroconductive particle contained in an anisotropic conductive adhesive is m, a ≥ e ≥ b c ≥ 0 f ≥ 0 d: m = 20: 1 to 200: 1 Plasma display panel, flexible printed circuit board, and crimping tool are arrange | positioned so that this may be satisfied. delete In the connection structure of the circuit which connects the electrode of a plasma display panel and the wiring terminal of a flexible printed circuit board by heat-pressing with a crimping tool through an anisotropic conductive adhesive, The width of the crimping tool a, the overlap width of the electrode of the plasma display panel and the wiring terminal of the flexible printed circuit board b, the distance from the flexible printed board side edge of the crimping tool to the electrode end of the plasma display panel c, the crimping tool The distance from the flexible printed circuit board side edge of the flexible printed circuit board edge to the end of the coverlay of the flexible printed circuit board (plus direction from the crimping tool edge to the flexible printed circuit board center part) d, and the width of the anisotropic conductive adhesive after connection e, when the distance from the plasma display panel side edge of a crimping tool to the wiring terminal end part of a flexible printed circuit board is f, and the average particle diameter of the electroconductive particle contained in an anisotropic conductive adhesive is m, a ≥ e ≥ b c ≥ 0 f ≥ 0 d: m = 20: 1 to 200: 1 Placing a plasma display panel, a flexible printed circuit board, and a crimping tool so that this is satisfied, The circuit connecting structure characterized by the above-mentioned.

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