JP3929473B2 - Method and apparatus for connecting signal cable of plasma display panel - Google Patents

Description

  The present invention relates to a method for manufacturing a plasma display panel, and more particularly to a method for electrically connecting an electrode terminal of a display panel and a circuit board using a flexible cable. In recent years, plasma display panels tend to be large, and the handling of display panels during the manufacturing process has become troublesome, so that it is necessary to simplify the manufacturing process.

  FIG. 6 is a perspective view for explaining the connection between a display panel (PDP) and a circuit board in a plasma display panel (hereinafter referred to as PDP) unit, and shows a state in which only a part is connected.

  In the PDP unit, as shown in FIG. 6, a metallic chassis 55 is attached to a display panel 53 including a pair of glass substrates, that is, a front glass substrate 51 and a rear glass substrate 52, and a circuit board 56 mounted on the chassis 55. And the electrode terminals of the glass substrates 51 and 52 are connected by a flexible cable 54.

  The flexible cable 54 and the glass substrates 51 and 52 are connected by a thermocompression bonding technique in which heat is applied via an anisotropic conductor. For example, as disclosed in JP-A-8-255568, a display panel is used. The pressure bonding part 53 is placed on a cradle and pressed by a pressure bonding head heated from above with the flexible cable 54 interposed.

Since the front glass substrate 51 and the rear glass substrate 52 constituting the display panel 53 are formed with electrode terminals on different surfaces, that is, opposite surfaces, the conventional method of heating and pressing from above the display panel 53 is described above. After the connection to one glass substrate, the display panel was inverted and the flexible cable was connected to the other glass substrate.
In FIG. 6, a part of the circuit board 56 and the flexible cable 54 mounted on the chassis 55 are omitted.
JP-A-8-255568

As described above, in the conventional thermocompression bonding process of the flexible cable 54, since the display panel 53 needs to be reversed, a manual operation or a large reversing device is required.
Such a process not only deteriorates the production efficiency but also increases the possibility of breakage of the display panel.
In particular, due to the layout of the circuit board mounted on the display panel, multiple flexible cables may be connected to the same circuit board, and multiple flexible cables are connected to the circuit board in advance by thermocompression bonding. In this state, when thermocompression bonding to the glass substrate is performed, it is difficult to position the terminals.

  The present invention solves these problems and eliminates the need for the inversion operation of the display panel in the connection process between the display panel and the flexible cable, thereby improving production efficiency and preventing damage to the display panel. An object of the present invention is to provide a signal display cable connection method and a connection apparatus for a plasma display panel.

In order to solve the above problems, the present invention has a plurality of display electrodes on the surface, the surfaces having the electrodes face each other, and the terminal rows of the electrodes led out to the edge are exposed. A front glass substrate and a rear glass substrate bonded together, and the electrode terminal rows of the front glass substrate are arranged at opposite ends of the substrate, and the electrode terminal rows of the rear glass substrate are front side In the method of connecting the electrode terminal row and the signal cable through an anisotropic conductive film of a plasma display panel arranged on the edge of a side intersecting the both edge sides of the glass substrate, the back glass substrate in a state of facing upward to support the plasma display panel, heat crimping a signal cable to be connected from above to the electrode terminal array derived in both edges of the front-side glass substrate A step of connecting at Rukoto, a step of connecting by thermocompression bonding by positioning the signal cable to be connected from the lower side of the electrode terminal sequence derived at one end edge of the rear side glass substrate, When continuously connecting a plurality of signal cables connected in advance to the circuit board in each connection step by heating and pressing each cable unit, the circuit board is attached to bend the signal cable. The plasma display panel is mounted on a mounting table having a level difference with respect to the surface on which the plasma display panel is supported, and the thermocompression bonding for each cable unit is sequentially performed .

According to the signal cable connecting method of the plasma display panel of the present invention, since the heat pressing is performed from both the upper side and the lower side when the signal cable and the display panel are connected, the display panel composed of a pair of substrates is provided. This eliminates the need for inversion, improving the production efficiency and preventing damage to the display panel.
In particular, since the mounting table having a step is designed to place and position a circuit board to which a plurality of communication cables are connected, the thermocompression bonding process can be performed after the communication cables have some bending. Since one communication cable that has already been crimped is not pulled by the other communication cable crimping due to the bending of the communication cable due to the stepped portion of the mounting table, it is possible to suppress the occurrence of misalignment.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a plan view for explaining a thermocompression bonding process between an electrode terminal of a PDP and a flexible cable according to an embodiment of the present invention, and FIG. 2 is a sectional view of the same.
As described above, the PDP unit is a circuit that drives display electrodes on the back surface of a display panel (PDP) in which a pair of glass substrates having display electrodes and the like are bonded together via a discharge space that encloses a discharge gas. It is configured with a substrate attached.
In this embodiment, a process of connecting a flexible cable for connection with a circuit board to an electrode of a glass substrate by thermocompression bonding will be described.

  As shown in FIG. 1, the front glass substrate 1 and the back glass substrate 2 are bonded together in consideration of the external dimensions and the opposing positional relationship so that the end face portions are exposed. Electrode terminals 3 a and 3 b are led out from the exposed end surface portion of the front glass substrate 1, and electrode terminals 4 are led out from the inside of the end surface portion of the rear glass substrate 2.

The present embodiment is directed to a three-electrode surface discharge type PDP, and each electrode terminal 3a, 3b, 4 corresponds to a pair of display electrodes and address electrodes.
The thermocompression bonding process in the present embodiment is carried out using thermocompression bonding units 5, 6 and 7 for crimping flexible cables corresponding to the electrode terminals 3a, 3b and 4, respectively. , 7 can slide as indicated by arrows and move up and down in the direction perpendicular to the paper surface.

  Although the details will be described later, after the display panel on which the pair of glass substrates are bonded is conveyed to a predetermined position, a predetermined number of flexible cables are first connected to the electrode terminals 3a of the front glass substrate 1 by the thermocompression bonding unit 5. Thereafter, a predetermined number of flexible cables are sequentially connected to the electrode terminal 3 b by the thermocompression bonding unit 6 and to the electrode terminal 4 by the thermocompression bonding unit 7.

The thermocompression bonding units 5 and 6 corresponding to the electrode terminals 3a and 3b of the front glass substrate 1 and the thermocompression bonding unit 7 corresponding to the electrode terminal 4 of the rear glass substrate 2 have different structures. That is, the thermocompression bonding units 5 and 6 are structured to perform heating and pressing from above, and the thermocompression bonding unit 7 is structured to perform heating and pressing from below. With such a structure, it is possible to continuously perform the thermocompression bonding process without inverting the display panel.
In addition, the expression of the front surface and the back surface in a glass substrate shows that it is located in the display surface side which image | photographs an image, and the back surface side which mounts a circuit board in the completion state of PDP.

  FIG. 2 is a cross-sectional view for explaining a specific crimping process by the thermocompression bonding units 5 and 6 for the front glass substrate 1 and the thermocompression bonding unit 7 for the back glass substrate 2. FIG. FIG. 2B illustrates the pressure bonding by the heat bonding unit 5 and FIG. 2B illustrates the pressure bonding by the heat bonding unit 7.

  As shown in FIG. 2A, the thermocompression bonding unit 5 for connecting the flexible cable 8 to the electrode terminal 3a (see FIG. 1) of the front glass substrate 1 moves the flexible cable 8 from the upper side to the front glass substrate 1 side. The heater block 9 to be pressed, the backup block 11 positioned on the lower side, and the suction pad 12 positioned on the lower side of the front glass substrate 1 and in the vicinity of the backup block 11 are configured.

When the display panel on which the front glass substrate 1 and the rear glass substrate 2 are bonded is conveyed to the crimping process, the backup block 11 is fixed so as to contact the lower surface of the crimped portion of the front glass substrate 1, and the same surface. The suction pad 12 that holds the vicinity of is disposed.
In this state, the flexible cable 8 is installed at a predetermined position on the front glass substrate 1 through an anisotropic conductive film (not shown), and the flexible cable 8 is pressed from above by the heater block 9. A heater 10 is built in the heater block 9, and heat is applied to the flexible cable 8 simultaneously with pressing.

  By the above operation, the electrode terminal of the front glass substrate 1 and the terminal of the flexible cable 8 are electrically connected via the anisotropic conductive film that melts. Since the anisotropic conductive film used for connection is in a state where conductive fine pieces are dispersed, adjacent terminals are not short-circuited.

At this time, the thermocompression bonding units 6 and 7 (see FIG. 1) for crimping the flexible cable to the other electrode terminal 3b of the front glass substrate 1 and the electrode terminal 4 of the rear glass substrate 2 are retracted to a region not involved in the crimping. The other pressure-bonding portion of the front glass substrate 1 is a free end, which enables a minute rotation as indicated by an arrow.
This rotation suppresses the occurrence of distortion due to the pressing of the heater block 9 on the glass substrates 1 and 2, and serves as a means for preventing the glass substrate from being damaged.
When the area of the glass substrate to be used is increased, the substrate is easily cracked due to distortion, so that the above means becomes effective as the display device is increased in size.

  After the connection of the predetermined number of flexible cables 8 to one electrode terminal 3 a of the front glass substrate 1 is completed, the flexible cable connection to the other electrode terminal 3 b of the front glass substrate 1 is performed using the thermocompression bonding unit 6. Since the thermocompression bonding unit 6 has the same configuration as the thermocompression bonding unit 5, it is not particularly illustrated.

  Thereafter, a flexible cable is connected to the electrode terminal 4 on the rear glass substrate 2. FIG. 2B is a cross-sectional view showing a crimping process by the thermocompression bonding unit 7. The thermocompression bonding unit 7 is positioned above the heater block 14 that presses the flexible cable 13 toward the rear glass substrate 2 from below. The back-up block 16 and the suction pad 17 located in the vicinity of the back-up block 16 above the rear glass substrate 2 are configured.

In this step, the backup block 16 is fixed so as to be in contact with the upper surface of the crimped portion of the rear glass substrate 2, and the suction pad 17 that holds the vicinity of the same surface is disposed.
In this state, the flexible cable 13 is installed at a predetermined position below the rear glass substrate 2 through an anisotropic conductive film (not shown), and the flexible cable 13 is pressed from below by the heater block 14. A heater 15 is built in the heater block 14, and heat is applied to the flexible cable 13 simultaneously with pressing.
By the above operation, the electrode terminal of the back glass substrate 2 and the terminal of the flexible cable 13 are electrically connected via the anisotropic conductive film that melts.

As with the cable connection to the front glass substrate 1, the other end of the rear glass substrate 2 becomes a free end, and the glass substrate can be prevented from being damaged by allowing a minute rotation as indicated by an arrow. Yes.
Note that the contact surfaces of the thermocompression bonding units 5 and 7 with the heater blocks 9 and 14 and the backup blocks 11 and 16 with the glass substrate are made of silicon rubber or the like, and a protective film for alleviating the impact at the time of contact. Is coated.
As described above, since it is possible to perform the thermocompression bonding process from different directions for the electrode terminals formed on the opposing surfaces, the troublesome process of inverting the display panel is not required, so that productivity is improved. In addition, the glass substrate can be prevented from being damaged.

Next, the structure of the thermocompression bonding portion of the flexible cable will be specifically described. 3A and 3B are diagrams showing the structure of the thermocompression bonding part, FIG. 3A is a perspective view, and FIG. 3B is a cross-sectional view.
The flexible cable 8 sandwiches a conductive wire between the base film 18 and the cover film 20, and is configured so that the leading end of the conductive wire is exposed as a terminal 19.
On the other hand, on the front glass substrate 1 to which the flexible cable 8 is connected, a plurality of electrode terminals 3a are formed, and these terminals are connected in a positioned state.

  At the time of connection, as shown in FIG. 3A, the anisotropic conductive film 21 is applied to the surface of the terminal 19 of the flexible cable 8 and the adhesive 22 for securing the connection strength is applied to the end of the cover film 20. To do. Such a flexible cable 8 is connected to the front glass substrate 1 by the thermocompression described in FIGS.

The anisotropic conductive film 21 and the adhesive 22 are attached to the flexible cable 8 by light adhesiveness before pressure bonding, and are melt-cured and bonded to the flexible cable 8 and the front glass substrate 1 by thermocompression bonding.
Then, the connection process to the front glass substrate 1 of the flexible cable 8 is complete | finished by apply | coating the sealing agent 23 which consists of silicon resin etc. and prevents electromigration.

  According to the thermocompression bonding structure of the present embodiment, reliable connection can be achieved, and crimping portion peeling due to external force after connection can be prevented. That is, even if an unexpected force in the direction of peeling from the front glass substrate 1 is applied to the flexible cable 8, the gap between the cover film 20 and the front glass substrate 1 is reinforced by the adhesive 22, so that the terminal There is little influence on the crimping part.

3A and 3B, the description has been given of the case where the flexible cable 8 is thermocompression bonded to the front glass substrate 1 from the upper side. However, the same applies to the crimped portion of the flexible cable 13 to the rear glass substrate 2 that performs crimping from the lower side. The structure is
Although not shown, the other end of the flexible cable 8 to be thermocompression bonded is connected to the circuit board in advance. And this circuit board is mounted on the back glass board | substrate 2 via a metallic chassis after the thermocompression-bonding process to the glass board | substrate of a flexible cable.

Next, another embodiment of the thermocompression bonding method will be described with reference to FIG. FIG. 4 is a perspective view and a cross-sectional view for explaining another embodiment of the thermocompression bonding method.
Due to the layout of the circuit board mounted on the display panel, multiple flexible cables may be connected to the same circuit board, and multiple flexible cables are connected to the circuit board in advance by thermocompression bonding or the like. In the state, when thermocompression bonding to the glass substrate is performed, positioning of the terminals becomes difficult.

  That is, for example, when thermocompression bonding is performed in a state where two flexible cables are connected to the same circuit board, immediately after crimping one flexible cable, it is already crimped when crimping the other flexible cable. The flexible cable is pulled toward the other flexible cable, and one flexible cable that is not completely fixed is displaced.

Therefore, in this embodiment, a plurality of (two) flexible cables are used as shown in FIG. 4 in order to suppress misalignment when thermocompression bonding is performed with a plurality of flexible cables connected to the same circuit board. The circuit board 34 to which the cable 33 is connected is placed on a mounting table 35 having a predetermined height, and the flexible cable 33 is given some bending, and then the thermocompression bonding process is performed.
If the flexible cable 33 is thermocompression bonded to the front glass substrate 31 in such a state, one flexible cable that has already been crimped due to the bending of the flexible cable 33 at the stepped portion of the mounting table 35 is replaced with the other flexible cable. Since it is not pulled by cable crimping, it is possible to suppress the occurrence of displacement.
Although the suction pad is omitted, the thermocompression bonding using the heater block 36 and the backup block 37 is not particularly different from the means described in FIG.

In addition, when a plurality of flexible cables are continuously thermocompression bonded, the tape-like anisotropic conductive film is applied to the back surface of the flexible cable while being cut into a predetermined length. Is briefly described below.
The anisotropic conductive film is cut with a metal cutter, but it is not easy to cut the anisotropic conductive film reliably for reasons such as the cutter being difficult to wear or adjusting the parallelism.

Therefore, cutting is performed while the anisotropic conductive film is thermally cured by a cutter heated to a predetermined temperature. The anisotropic conductive film has a property of being cured at a predetermined temperature, and is easily cut by being cured. Therefore, by weakening the contact pressure between the cutter and the anisotropic conductive film, it is possible to reliably cut only the anisotropic conductive film without cutting the terminals of the flexible cable and the base film.
In addition, since the contact pressure with the anisotropic conductive film can be weakened, wear can be suppressed.

In the thermocompression bonding process described above, in the unlikely event that the position of the flexible cable is displaced, it is necessary to perform re-bonding (repair). A suitable means for the flexible cable peeling method at the time of repair will be described below. .
FIG. 5 is a perspective view for explaining a peeling process at the time of repair.

Since the anisotropic conductive film is softened by heating to a high temperature of about 200 ° C. and weakens the adhesive force, this embodiment uses this, and a hot air nozzle 46 shown in FIG. 5 is used.
The hot air nozzle 46 is located above the anisotropic conductive film 45 that connects the flexible cable 43 and the electrode terminal 44 of the front glass substrate 41, and supplies hot air partially.
When the anisotropic conductive film 45 is softened by the hot air, the flexible cable 43 is pulled in the direction indicated by the arrow, and the crimping portion is peeled off.

When hot air directly hits the front glass substrate 41 or the back glass substrate 42, the temperature of the glass substrate may rise locally and cracks due to thermal distortion may occur. Since the hot air is supplied from the nozzle 46, it is possible to partially apply the hot air to a necessary portion, thereby avoiding the problem of substrate cracking.
An anisotropic conductive film may remain on the substrate, but it can be removed with a heated solvent.
As described above, after the flexible cable 43 is peeled off and the residue of the anisotropic conductive film is removed, alignment is performed again and a thermocompression bonding process is performed.

It is a top view for demonstrating the thermocompression-bonding process which concerns on this invention. It is sectional drawing for demonstrating the thermocompression bonding process which concerns on this invention. It is the perspective view and sectional drawing which show the structure of the thermocompression bonding part which concerns on this invention. It is a figure for demonstrating the other Example of the thermocompression bonding which concerns on this invention. It is a perspective view for demonstrating the peeling process which concerns on this invention. It is a perspective view which shows the connection state of the display panel of a PDP unit, and a circuit board.

Explanation of symbols

1 Front glass substrate 2 Rear glass substrate 3a, 3b, 4 Electrode terminal 8, 13 Signal cable (flexible cable)
21 Anisotropic conductive film 22 Adhesive

Claims (2)

A front glass substrate and a back surface bonded together so that each surface has a plurality of display electrodes, the surfaces having the electrodes face each other, and the terminal rows of the electrodes led out to the edge are exposed. The electrode terminal row of the front side glass substrate is constituted by a glass substrate, and the electrode terminal row of the back side glass substrate is arranged on the opposite side edge side of the front side glass substrate. In the method of connecting the electrode terminal array and the signal cable of the plasma display panel arranged on the edge via an anisotropic conductive film,
With the back glass substrate facing up and supporting the plasma display panel, the signal cable to be connected to the electrode terminal array led to both end edges of the front glass substrate is connected by thermocompression bonding from above. And a process of
The step of connecting by thermocompression bonding the signal cable to be connected to the electrode terminal array derived to an edge of the rear side glass substrate is positioned from the lower side, with continuously performed,
The plasma display panel supports the circuit board so as to impart a bending state to the signal cable when the plurality of signal cables connected in advance to the circuit board in each connection step are connected by heating and pressing each cable unit. A signal cable connection method for a plasma display panel, which is mounted on a mounting table having a level difference with respect to the surface to be heated and sequentially subjected to thermocompression bonding for each cable unit . Front side glass substrate and rear side glass each having a plurality of display electrodes on the surface, the surfaces having the electrodes facing each other, and the terminal rows of the electrodes led out to the edge are exposed. The electrode terminal rows of the front glass substrate are arranged at opposite opposite edges of the substrate, and the electrode terminal rows of the rear glass substrate are ends of sides intersecting the both edge sides of the front glass substrate. In the apparatus for connecting the electrode terminal row and the signal cable of the plasma display panel arranged on the edge via an anisotropic conductive film,
Support means for supporting the plasma display panel to be connected in a state in which the glass substrate on the back side is on top,
Means for positioning from above the signal cable to be connected to the electrode terminal row led to both end edges of the front glass substrate;
A backup block that contacts the lower surface of the substrate arranged corresponding to each of the electrode arrangement positions on both ends of the front glass substrate, and a heater block that can be crimped by moving in the arrangement direction of the electrode terminal row above the substrate. A pair of front side thermocompression bonding units consisting of:
Means for positioning from the lower side a signal cable to be connected to the electrode terminal row led to one end edge of the rear side glass substrate;
From a backup block that comes into contact with the upper surface of the substrate arranged corresponding to the electrode arrangement position of one end edge of the rear glass substrate, and a heater block that can be crimped by moving in the arrangement direction of the electrode terminal row below the substrate A back side thermocompression unit
The positioning means of the signal cable to be connected has a configuration of a mounting table having a step with respect to a surface on which a plasma display panel for imparting a bent state to the signal cable of a circuit board previously connected to the signal cable is supported. A signal cable connecting device for a plasma display panel , characterized by comprising:

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