JPH10301503A - Plane display device and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To adapt the device to high definition achieved by increasing the number of electrodes and to prevent breakage by reducing stress on a display panel by connecting electrode terminals of the display panel and terminals of a flexible cable by conductive wires. SOLUTION: On a front glass substrate 1 at a fixed interval to the electrode terminals 4, the flexible cable 5 is fixed by using an adhesive, and the cable terminals led out to the end part of the flexible cable 5 and the electrode terminals 4 are electrically connected by the wires 7 such as gold wires. Then the part where the wires 7 are formed is coated with insulating resin 8 for protection. Namely, the terminals 4 and 6 are connected by the thin wires 7, so even if the terminal pitch becomes narrow as the definition is improved, the flexible cable 5 can precisely be connected. Further, the stress on the display panel 3 is reduce since the wire 7 is connected under weak pressure to prevent breakage.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flat display device such as a plasma display panel or a liquid crystal display panel comprising a pair of substrates having display electrodes, and a method of manufacturing the same. The present invention relates to an apparatus having a configuration for electrically connecting using a flexible cable and a manufacturing method.

2. Description of the Related Art In recent years, flat display devices have tended to have higher definition and the pitch between electrode terminals has become narrower. Therefore, it is necessary to connect electrode terminals of a display panel to a flexible cable with high precision. It has become.

[0003]

2. Description of the Related Art FIG. 8 is a diagram for explaining a conventional flat panel display device and a manufacturing method. Here, a plasma display panel (hereinafter referred to as a PDP) will be described as an example.
FIG. 8A is a perspective view of a state in which a flexible cable is connected to a display panel of a PDP, and FIG. 8B is a cross-sectional view illustrating a connection process.

A PDP is a display panel formed by bonding a pair of glass substrates on which display electrodes and the like are formed via a predetermined discharge space, and a substrate on which a circuit for driving the display electrodes is mounted (hereinafter, a circuit board). ) And the display panel and the circuit board are connected by a flexible cable. A connection structure and a connection method of a flexible cable for connecting the display electrode and the circuit board to the display panel will be described below.

[0005] A front glass substrate 21 serving as a display surface and a rear glass substrate 22 serving as a circuit board mounting surface are bonded so that electrodes face each other and an electrode terminal 24 serving as an electrode lead-out portion is exposed. ing. FIG. 8A shows only a part of the electrode terminals 24. This electrode terminal 2
As means for electrically connecting the circuit board 4 to the circuit board, a flexible cable 25 having a conductive cable disposed in a film sheet is used. The connection is directly performed by thermocompression bonding to the electrode terminals 24.

[0008] In FIG. 8, the electrode terminals 24 of the front glass substrate 21 are turned upward, and a state in which a flexible cable 25 is crimped to the electrode terminals 24 can be seen. Although the back glass substrate 22 side is hidden downward and cannot be seen,
Similarly, the electrode terminal and the flexible cable are crimped. A printed circuit board 26 is also connected in advance to the other end of the flexible cable 25 by thermocompression bonding. The printed circuit board 26 is formed by bending the flexible cable 25 onto the rear glass substrate 22 via a chassis (not shown). Will be installed.

In the thermocompression bonding step, first, a tape-like anisotropic conductive film is applied so as to cover a cable terminal (not shown) of the flexible cable 25, and an adhesive tape for temporary bonding is applied to the film portion, and this is displayed. Temporary bonding is performed at a predetermined position of the panel 23, that is, in a state where the terminals overlap each other. Then, FIG.
Compression is performed using a thermocompression device 27 as shown in FIG.
The thermocompression bonding device 27 is composed of a heater block 28 having a built-in heater 29 and a backup block 30. By sandwiching the flexible cable 25 and the display panel 23 at a predetermined temperature and pressure, an anisotropic conductive film is used. The flexible cable 25 and the electrode terminal 24 are fused.

The contact portion between the heater block 28 and the backup block 30 is covered with an elastic member for preventing the display panel from being damaged. The conventional thermocompression bonding process described above is also disclosed in, for example, JP-A-8-255568.

[0009]

As described above, according to the conventional connection of the flexible cable 25 to the display panel 23 by thermocompression bonding, the electrode terminals 24 formed on the display panel 23 and the terminals of the flexible cable 25 are in direct contact. Connection, a slight misalignment leads to poor connection.

In particular, when the terminal pitch becomes narrow due to an increase in the number of electrodes or the like, the possibility increases, and when the positional deviation increases, the connection of different terminals causes a malfunction of the device. Therefore, it will not be possible to cope with future high definition in PDP and the like.

In the thermocompression bonding step, since the display panel 3 is heated and pressed from above and below as described above, the stress on the thin glass substrate is large, and may cause breakage depending on the state of the glass substrate. For example, if a flexible cable is simultaneously pressed against opposite ends of a display panel, the glass substrate will be broken due to distortion.

Therefore, the crimping of the flexible cable to the display panel must be performed for each end, which lowers the production efficiency. The present invention solves the above-mentioned problems, and by accurately connecting a flexible cable even in a narrow terminal pitch, it is possible to cope with a high definition in which the number of electrodes is increased and to reduce stress on a display panel. The purpose is to prevent damage.

[0013]

In order to solve the above-mentioned problems, the present invention employs a structure in which the electrode terminals 4 of the display panel 3 and the terminals 6 of the flexible cable 5 are connected by conductive wires 7. . According to such a configuration,
Since the terminals are connected by the thin wire 7, the connection of the flexible cable can be performed accurately even at a narrow terminal pitch, and the connection can be performed with a small pressure, so that the stress on the display panel is reduced. It is possible to mitigate and prevent breakage.

[0014]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a perspective view and a sectional view showing a main part of an embodiment in which the present invention is applied to a plasma display panel (hereinafter, referred to as a PDP). As described in the section of the related art, the PDP includes a display panel formed by bonding a pair of glass substrates on which display electrodes and the like are formed through a predetermined discharge space, and a circuit board that controls the display electrodes. FIG. 1A and FIG. 1B show a characteristic portion of the present invention, that is, a connection portion between a display panel and a flexible cable.

As apparent from FIG. 1A, the front glass substrate 1 serving as a display surface and the rear glass substrate 2 on which a circuit board is mounted have different external dimensions, and a predetermined discharge space is interposed therebetween. In the state of the display panel 3 bonded together, both ends protrude outward from the other edge. The terminal 4 of the display electrode is led out to the overhanging portion. FIG. 1 shows only the electrode terminal 4 at one end of the front glass substrate 1.

In this embodiment, a flexible cable 5 is provided on the front glass substrate 1 at a fixed distance from the electrode terminal 4.
Are fixed using an adhesive, and a cable terminal 6 led out to an end of the flexible cable 5 and the electrode terminal 4 are electrically connected by a wire 7 such as a gold wire. Then, as shown in FIG. 1B, a portion where the wire 7 is formed is covered with a protective insulating resin 8.

2 to 4 are views for explaining a method of manufacturing the PDP shown in FIG. 1, FIG. 2 is a sectional view, and FIGS. 3 and 4 are plan views. 2 to 4, the same parts as those in FIG. 1 are denoted by the same reference numerals. A display panel 3 in which a front glass substrate 1 and a rear glass substrate 2 are bonded to each other and a discharge gas such as a mixed gas of neon and xenon is sealed in a discharge space, as shown in FIG. 2
Is transported to a predetermined processing apparatus by the transport path 18 in a state in which the electrode terminals 4 of the front glass substrate 1 face upward, that is, with the electrode terminals 4 facing upward.

In connecting the flexible cable to the display panel 3, first, as shown in FIG. 2A, a band-shaped adhesive tape 9 is attached to the back surface of the flexible cable 5 from which the cable terminal 6 is led out. In this step, the long adhesive tape wound in a roll shape is cut to a desired length and attached to the back surface of the flexible cable 5 by an automatic device.

As shown in FIGS. 2B and 3B, the flexible cable 5 to which the adhesive tape 9 is attached
It is fixed to the end of the front glass substrate 1 facing the electrode terminal 4 with a slight gap therebetween by the adhesive force of the adhesive tape 9. This step is performed simultaneously on both ends of the front glass substrate 1 by an automatic device (not shown) which is disposed on both sides of the transport path 18 in FIG. 3 and has an arm for holding and moving the flexible cable 5. At this time, the front glass substrate 1 and the flexible cable 5 are positioned by an alignment mark provided in advance.

Incidentally, at one end of the flexible cable 5,
As shown in FIG. 3B, a printed circuit board 17 mounted on the rear glass substrate 2 is fixed in advance by, for example, thermocompression bonding over a plurality of (here, two) flexible cables 5. The display panel 3 to which such a flexible cable 5 is fixed is further transported by a transport path 18, and
The processing described below is performed.

In this step, for example, what is called wire bonding performed in the field of semiconductors is performed.
As shown in FIG. 3C and FIG.
The electrode terminal 4 and the cable terminal 6 are electrically connected by a wire 7 made of a gold wire. As will be described later with reference to the drawings, the wires 7 are bonded in a loop between the electrode terminals 4 and the cable terminals 6 by using bonding devices disposed on both sides of the transport path 18.

When the bonding of the wire 7 is completed,
As shown in FIGS. 2 (d) and 3 (d), the insulating resin for protection, for example, silicon, is transported on the transport path 18 so as to cover all the electrode terminals 4 and the cable terminals 6 including the wires 7 as shown in FIGS. The resin 8 is applied. The application of the insulating resin 8 is also performed simultaneously by the coating devices arranged on both sides of the transport path 18.

As described above, the connection of the flexible cable 5 to the front glass substrate 1 is completed by applying the insulating resin 8. In this embodiment, the electrodes formed on the front glass substrate 1 are discharge electrodes for generating a discharge between a pair of electrodes by applying a voltage, and the electrode terminals 4 are alternately provided at both ends of the front glass substrate 1. Is derived. The electrodes formed on the rear glass substrate 2 are address electrodes for selecting discharge regions in the discharge electrodes of the front glass substrate 1, and are led out only to one end.

Therefore, the process of connecting the flexible cable to the front glass substrate 1 described above is performed simultaneously at both ends of the substrate. On the other hand, the back glass substrate 2 described below
, A flexible cable is connected to only one end. After the connection of the flexible cable 5 to the front glass substrate 1 is completed, the display panel 3
Is turned over by a reversing device (not shown), and the front glass substrate 1 is set on the transport path 18 ′ as shown in FIG. 4, with the electrode terminals 4 ′ of the rear glass substrate 2 facing upward.

In the rear glass substrate 2, since the address electrodes are led out only to one end of the substrate as described above, each processing is performed only from one side of the transport path 18 '. The connection of the flexible cable 5 'to the rear glass substrate 2 is, like the connection to the front glass substrate 1, first fixed to a printed circuit board 17' as shown in FIG. The fixed flexible cable 5 'is fixed at a position facing the electrode terminal 4'.

Thereafter, as shown in FIG. 4B, the electrode terminals 4 'and the cable terminals of the flexible cable 5' are electrically connected by wires 7 '. Then, although not shown, an insulating resin for protecting the wires 7 ', the electrode terminals 4', and the cable terminals is applied to complete the connection of the flexible cable. The cross-sectional structure of the connection of the flexible cable 5 'to the rear glass substrate 2 is the same as that shown in FIG.

FIGS. 5 and 6 are views for explaining the wire bonding step according to the present invention. FIG. 5 is an external perspective view, and FIG. 6 is a sectional view showing the internal structure of the bonding apparatus. The perspective view of FIG. 5 shows a state in which the display panel 3 in which the flexible cable 5 is fixed to the front glass substrate 1 is placed on a processing stage, and bonding apparatuses 10 are arranged on both sides of the processing stage. I have.

The bonding apparatus 10 is installed on a rail 12 arranged in parallel with the edge of the display panel 3 and shown in FIG.
As shown in the figure, a capillary 11 for supplying a wire 13 from the tip is provided via a movable arm 19.
In a state where the display panel 3 to which the flexible cable 5 is fixed is placed on a processing stage, the cable terminal 6 of the flexible cable 5 is connected to the electrode terminal 4 of the front glass substrate 1 (all shown in FIG. 2). The wires are sequentially bonded, and a specific example thereof will be described below.

First, as shown in FIG. 6, the capillary 11 for supplying the wire 13 is positioned above the flexible cable 5, and a ball is generated at the end of the wire by a flame obtained by burning hydrogen gas at the end. Then, the wire 13 is crimped to the cable terminal of the flexible cable 5 by lowering the capillary 11. Then, the capillary 11 is moved so as to draw a loop, the other end of the wire 13 is crimped to the electrode terminal 4, and then the wire is cut to complete the electrical connection by the wire.

The capillary 11 is provided with a pair of optical fibers 14 for emitting and receiving light. After the presence or absence of the cable terminal is recognized by the reflected light from the cable terminal, wire bonding is performed. I have.
Further, the movable arm 19 is provided with a recognition camera 15 for recognizing whether or not the electrode terminal 4 exists at a position facing the cable terminal.

When it is confirmed by the optical fiber 14 and the recognition camera 15 that the terminal is not at a predetermined position, a signal is sent to a control unit (not shown) for controlling the bonding apparatus to move the capillary 11 before bonding. Let it. Therefore, even if the flexible cable is displaced or the like, a connection failure does not occur.

By repeating the above processing,
Wire bonding is performed between a plurality of terminals. still,
In the present embodiment, the connection of a plurality of flexible cables is sequentially performed by moving one bonding apparatus on one side. However, a plurality of bonding apparatuses are installed so as to correspond to the flexible cable, and are simultaneously connected. By performing the wire connection, it is possible to further increase the production efficiency.

FIG. 7 is a diagram showing a wiring example of a flexible cable in a state where a printed circuit board fixed to the flexible cable is mounted on a rear glass substrate. A chassis 16 made of aluminum or the like is fixed to the rear glass substrate 2 with an adhesive, and a printed board 17 ′ for controlling electrodes is mounted on the chassis with screws or the like.

The flexible cable 5 ′ connected to the electrode terminal of the rear glass substrate 2 is drawn out to the surface of the chassis 16 along the side surface of the rear glass substrate 2 and the side surface of the chassis 16. Therefore, when fixing the flexible cable 5 ′ to the end of the rear glass substrate 2, the adhesive tape 9 ′ is arranged from the surface to the side surface of the rear glass substrate 2 as shown in FIG.

According to this configuration, the fixing strength of the flexible cable 5 'is increased, and it is possible to prevent conduction failure due to intrusion of moisture or the like without applying a protective resin to the bonding surface. However, when the flexible cable is connected to the front glass substrate 1, it does not contact the side surface of the substrate, so it is necessary to apply a protective resin.

The PDP has been described as an example in the embodiments, but the present invention can be applied to a configuration including a display panel having electrodes for display at night and a circuit board, such as a liquid crystal display device.

[0037]

According to the flat display device and the manufacturing method of the present invention, since the terminals are connected to each other by the fine wire, the flexible cable can be precisely formed even if the terminal pitch is narrowed with high definition. And the wire connection is performed with a weak pressure, so that stress on the display panel can be reduced to prevent breakage.

[Brief description of the drawings]

FIG. 1 is a view showing one embodiment of a flat panel display device of the present invention.

FIG. 2 is a cross-sectional view for explaining one embodiment of the manufacturing method of the present invention.

FIG. 3 is a plan view (1) for explaining one embodiment of the manufacturing method of the present invention.

FIG. 4 is a plan view (2) for explaining one embodiment of the manufacturing method of the present invention.

FIG. 5 is a perspective view for explaining wire bonding according to the present invention.

FIG. 6 is a sectional view for explaining wire bonding according to the present invention.

FIG. 7 is a sectional view showing a wiring example of the flexible cable according to the present invention.

FIG. 8 is a view for explaining a conventional flat panel display device and a manufacturing method.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Front glass substrate 2 Back glass substrate 3 Display panel 4, 4 'Electrode terminal 5, 5' Flexible cable 6 Cable terminal 7, 7 'Wire 8, 8' Insulating resin 9 Adhesive tape 10 Bonding device

Claims (5)

[Claims] 1. A flat panel display device comprising a display panel and a circuit for driving the display panel, wherein the display panel and the drive circuit are electrically connected by a flexible cable. A flat display device, wherein an electrode terminal exposed at an end and a terminal of the flexible cable are connected by a conductive wire. 2. The flat display device according to claim 1, wherein the flexible cable is fixed to an end portion of the substrate where the electrode terminal is exposed so as to face the electrode terminal with an adhesive. 3. A display panel comprising a pair of substrates having display electrodes bonded together so that the display electrodes are exposed at ends, and a circuit for driving the display electrodes, wherein the display panel and the drive In a method of manufacturing a flat display device in which a circuit is electrically connected to a flexible cable by a flexible cable, a first step of fixing a flexible cable for leading a cable terminal to an end of a substrate facing the electrode terminal at a predetermined interval, A second step of connecting between the electrode terminal and the cable terminal to be connected by a conductive wire, and a third step of forming a protective film covering the electrode terminal and the cable terminal connected by the wire. A method for manufacturing a flat display device characterized by the above-mentioned. 4. The first to third steps are performed on one of the substrates in a state where the display panel is installed such that the electrode terminals of one of the substrates constituting the display panel face upward. 4. The method according to claim 3, wherein the display panel is turned over, and the first to third steps are performed on the other substrate. 5. The flat display device according to claim 3, wherein the first to third steps are simultaneously performed on electrode ends led to both ends of a substrate forming the display panel. Production method.