CN100416624C - Bonding structure of bonding electrode and circuit board electrode and flat display device - Google Patents

Abstract

The invention discloses a bonding structure of a bonding electrode and a circuit board electrode and a flat panel display device comprising the same. The bonding structure includes: a first substrate having a first surface; a plurality of bonding electrodes formed on the first surface of the first substrate with a second surface, the bonding electrodes having a third surface on an opposite side of the second surface and having bonding regions at edges of the first substrate and non-bonding regions; the anisotropic conductive adhesive layer is formed on the first surface of the first substrate and the third surface of the bonding electrode and completely covers the bonding area; and a circuit board with at least one circuit board electrode formed on the bonding layer, wherein the circuit board electrode is fixed on the corresponding bonding electrode by the bonding layer, and the circuit board electrode is tightly bonded with the corresponding bonding electrode by the bonding layer. The anisotropic conductive adhesive layer completely covers the bonding electrode and prevents the bonding electrode from being exposed, so that the bonding strength between the bonding electrode and the circuit board electrode can be further increased, and the stability of the product can be improved.

Description

Bonding structure of bonding electrode and circuit board electrode and flat display device

technical field

The invention relates to a bonding structure of a bonding electrode and a circuit board electrode, in particular to a bonding structure of a bonding electrode and a circuit board electrode used in a flat panel display device.

Background technique

In recent years, various new types of flat panel display (FPD) have been continuously developed and designed, such as liquid crystal display (liquid crystal display; LCD), organic light emitting display (organic light emitting diode, OLED) and plasma display, and there are Gradually replace the traditional cathode ray tube (cathode ray tube; CRT) trend. Among them, the plasma display is a flat display device that emits light by gas discharge, and its biggest feature is that it is light, thin, easy to enlarge and has no viewing angle problem.

In general plasma displays, after the front substrate and the rear substrate are sealed to form a closed discharge cell, a plurality of circuit board electrodes are connected to the bonding regions of the bonding electrodes on the front substrate and the rear substrate. Since the circuit board electrodes are used to form electrical connections to the outside, the strength and reliability of the bonding structure between the circuit board electrodes and the bonding electrodes will affect the quality of the plasma display.

Please refer to FIG. 1 , which shows a top view of the bonding area formed after the front substrate and the rear substrate of the plasma display are sealed. The plasma display 10 includes a front substrate 12 and a rear substrate 14 disposed in parallel above the front substrate 12 , and a plurality of bonding electrodes 16 are formed between the two substrates. Taking the bonding structure of the front substrate 12 as an example, the bonding electrodes 16 extend to the edge of the front substrate 12, and a dielectric layer 18 is formed on the plurality of bonding electrodes 16 to protect the bonding electrodes 16; And the bonding electrode 16 that is not covered by this dielectric layer 18 is used as a bonding area 20, wherein, has a circuit board electrode predetermined area 22 in this bonding area 20, and this bonding area 20 is used for connecting with a circuit board Make electrical connections.

And the bonding structure of the bonding electrode and circuit board electrode of traditional plasma display, please refer to Fig. In the cross-sectional view of line 3a-3a' in FIG. Finally, after thermocompression bonding (bonding), the circuit board electrode 42 is electrically connected to the bonding electrode 16 through the electrical connection layer 30 . Wherein, the electrical connection layer 30 is not only used for electrically connecting the bonding electrodes 16 and the circuit board electrodes 42 , but also used for bonding the front substrate 12 and the circuit board 40 .

However, in the bonding structure of the bonding electrode 16 and the circuit board electrode 42 of the conventional plasma display, the electrical connection layer 30 only exists in the overlapping portion of the bonding electrode 16 and the circuit board electrode 42, even after thermocompression bonding process, the electrical connection layer overflow region 32 formed by the overflowing electrical connection layer 30 cannot cover the bonding electrode exposed region 28 or exceed the boundary 13 of the front substrate 12, so the bonding strength of this structure is not very good, as shown in FIG. 3A.

In addition, since the bonding electrode 16 is still partly exposed, the exposed region 28 of the bonding electrode often needs to be additionally coated with a layer of silica gel layer 34, please refer to FIG. 3B to protect the bonding electrode 16 and simultaneously isolate the atmosphere and the The contact of the bonding electrode 16, thereby maintaining the stability of the plasma display and passing the reliability test; moreover, the silicone layer 34 can also be further formed between the edge 13 of the front substrate 12 and the circuit board 40 to increase the bonding strength . However, this additional silicone layer coating step will inevitably reduce the process speed of the product and increase the manufacturing cost.

Therefore, to further improve and design the relative relationship between the electrical connection layer, the bonding electrodes and the circuit board electrodes, so as to improve the strength of the bonding structure of the circuit board electrodes and the bonding electrodes and increase the reliability of the flat panel display device, is a A very important subject.

Contents of the invention

In view of this, in order to solve the above problems, the main purpose of the present invention is to improve and design the relative relationship between the anisotropic conductive adhesive layer, the bonding electrode and the circuit board electrode, so as to provide a bonding electrode and circuit with high bonding strength. The bonding structure of the plate electrode, in addition to electrically connecting the bonding electrode and the circuit board electrode, since the anisotropic conductive adhesive layer completely covers the bonding electrode to avoid its exposure, it can further increase the bonding electrode and the circuit board electrode. the bond strength.

Another object of the present invention is to provide a flat panel display device, which has a bonding structure of bonding electrodes and circuit board electrodes with high bonding strength. relationship, so that the anisotropic conductive adhesive layer completely covers the bonding electrode, not only increases the bonding strength between the bonding electrode and the circuit board electrode, and the anisotropic conductive adhesive layer further protects the bonding electrode, greatly improving the performance of the flat-panel display device. stability.

The planar display device of the present invention, if cooperate with the bonding electrode that forms with thick film (thick film) process mode, for example silver-containing electrode, then except the adhesive material that adds, completely cover the anisotropic conduction of bonding electrode The adhesive layer also constitutes a protective layer to block the infiltration of water vapor, reduce the migration of silver atoms (Agmigration), and then avoid the phenomenon of short circuit of the bonding electrode; Adding other adhesive materials can isolate the contact between the bonding electrode and the atmosphere and increase the stability of the product.

In order to achieve the above object, the bonding structure of the bonding electrode and the circuit board electrode according to the present invention includes a first substrate, the first substrate has a first surface, and on the first surface of the first substrate A plurality of bonding electrodes are formed, wherein the plurality of bonding electrodes contact the first surface of the first substrate with a second surface, and the bonding electrodes have a third surface on the opposite side of the second surface, And the bonding electrode has a bonding area and a non-bonding area at the edge of the first substrate. Part of the third surface of the plurality of bonding electrodes can also be further covered with a second substrate, exposing the bonding area. In addition, an anisotropic conductive adhesive layer is formed on the first surface of the first substrate and the third surface of the bonding electrode, and completely covers the bonding area, and a circuit board having at least one circuit board electrode is formed on the anisotropic conductive adhesive layer, and fixed on the bonding electrode with the anisotropic conductive adhesive layer, and the gap between the circuit board electrode and the bonding electrode is covered with the anisotropic conductive adhesive layer adaptation.

According to the bonding structure of the bonding electrode and the circuit board electrode of the present invention, an adhesive material is formed on the anisotropic conductive adhesive layer and the circuit board electrode to prevent water vapor from infiltrating.

According to the bonding structure of the bonding electrode and the circuit board electrode of the present invention, an insulating layer is formed on the non-bonding area of the third surface of the bonding electrode.

Based on another object of the present invention, a flat-panel display device having a bonding structure of bonding electrodes and circuit board electrodes with high bonding strength according to the present invention includes at least a first substrate, and the first substrate has a first surface , and a plurality of bonding electrodes are formed on the first surface of the first substrate, wherein the plurality of bonding electrodes contact the first surface of the first substrate with a second surface, and the bonding electrodes have a The third surface is opposite to the second surface. Part of the third surface of the plurality of bonding electrodes is also covered by a second substrate, and the other third surface not covered by the second substrate includes a bonding area and a non-bonding area. In addition, an anisotropic conductive adhesive layer is formed on the first surface of the first substrate and the third surface of the bonding electrode, and completely covers the bonding area, and a circuit board having at least one circuit board electrode is formed on the anisotropic conductive adhesive layer, and fixed on the bonding electrode with the anisotropic conductive adhesive layer, and the gap between the circuit board electrode and the bonding electrode is filled with the anisotropic conductive adhesive The layers are tight.

According to the flat panel display device of the present invention, wherein the first substrate can be a front panel, and the second substrate can be a rear panel; on the other hand, the first substrate can also be a rear panel, and the first substrate can be a rear panel. The second base board can also be a front board.

In order to make the above objects and features of the present invention more comprehensible, preferred embodiments will be described below in detail with accompanying drawings.

Description of drawings

Fig. 1 shows the top view of the bonding area formed after the front substrate and the rear substrate of the conventional plasma display are sealed;

Fig. 2 shows the top view of the bonding structure of the bonding electrode and the circuit board electrode of the traditional plasma display;

3A and 3B show a cross-sectional view of a bonding structure of a bonding electrode of a conventional plasma display and a circuit board electrode;

4A to 4C show a top view of the bonding structure of the bonding electrode and the circuit board electrode of the plasma display according to the present invention;

Fig. 5 shows the bonding structure sectional view of its bonding electrode and circuit board electrode of plasma display according to the present invention;

6A to 6C show cross-sectional views of the structure of a plasma display device according to a preferred embodiment of the present invention;

7 shows a cross-sectional view of the structure of a plasma display device according to other preferred embodiments of the present invention; and

FIG. 8 shows a perspective view of a flat display device according to a preferred embodiment of the present invention.

Explanation of reference signs

10 Plasma Display 12 Front Substrate

13 Boundary of front substrate 14 Rear substrate

16 Bonding electrode 18 Insulation layer

20 Bonding area 22 Circuit board electrode reservation area

28 Bonding electrode exposure area 30 Electrical connection layer

32 Overflow area of electrical connection layer 40 Circuit board

42 Circuit board electrode 100 Plasma display

102 First substrate 104 Second substrate

113 The boundary of the first substrate 115 The first interface

116 Bonding electrode 118 Insulation layer

120 Bonding area 128 Bonding electrode exposed area

130 Anisotropic conductive adhesive layer 140 Circuit board

142 Circuit board electrode 200 Flat panel display device

3a-3a’ along the section line of 3a-3a’ 5-5’ along the section line of 5-5’

Detailed ways

The bonding structure of the bonding electrode and the circuit board electrode and the flat display device comprising the structure according to the present invention are characterized in that the anisotropic conductive adhesive layer completely covers the bonding electrode not connected with the circuit board electrode. The exposed area of the bonding electrode, and the anisotropic conductive adhesive layer can further completely cover the edge of the bonding electrode, so that the bonding strength between the electrodes will be greatly improved, and the short circuit of the bonding electrode can be avoided. Hereinafter, the bonding structure of the high bonding strength bonding electrodes and the circuit board electrodes of the present invention will be described in detail with reference to the accompanying drawings and by taking a plasma display device as an example.

First, please refer to FIG. 4A , which shows a top view of the bonding structure designed on the substrate of the plasma display device according to the present invention, so as to further explain the definition and relative relationship of the components in the present invention. The plasma display device 100 includes a first substrate 102 and a second substrate 104 , and the second substrate 104 is disposed above the first substrate 102 in parallel after alignment. Taking the bonding structure of the first substrate 102 as an example, there is a bonding region 120 outside the sealing place between the first substrate 102 and the second substrate 104, and in the bonding region 120, there are multiple The bonding electrodes (not shown) that can be electrically connected are approximately in the shape of a strip. Wherein, an insulating layer 118 may also be formed on a plurality of bonding electrodes (not shown) outside the bonding region 120 to protect the bonding electrodes. The insulating layer 118 can be a dielectric layer; and the material of the bonding electrode can be an electrode containing silver, or any one or more of chromium, copper, aluminum, nickel, tungsten and cobalt. Alloys or laminates, and the manufacturing process of the bonding electrodes can be photosensitive thick film method, photosensitive thin film method or screen printing method.

Please still refer to FIG. 4A , the bonding structure of the present invention is connected to the first substrate 102 by a circuit board 140 . Please refer to FIG. 5 , which is a sectional view corresponding to the tangent line 5-5' in FIG. The bonding electrode 116 on the upper surface is connected, and the circuit board electrode 142 is fixed on the part of the surface of the bonding electrode 116 corresponding to it by the anisotropic conductive adhesive layer 130, and through the anisotropic conductive adhesive layer 130 realizes the electrical connection between the circuit board electrode 142 and the bonding electrode 116 . Wherein, the anisotropic conductive adhesive layer 130 is electrically connected at the place where it is pressed, and may be an anisotropic conductive film (ACF) containing conductive particles, and the conductive particles may be coated on the surface Metal particles of gold, silver or nickel; the circuit board electrode 142, which can be carried by a tape automatic bonding method or a flip-chip bonding method, is connected to the bonding electrode 116 through the anisotropic conductive adhesive layer 130 , to be formed on the bonding electrode 116 .

The key point of the design of the bonding structure of the present invention is that it is used as the anisotropic conductive adhesive layer 130 connecting the circuit board electrode 142 and the bonding electrode 116 to perform a thermocompression bonding process on the first substrate 102 and the circuit board 140 Afterwards, the anisotropic conductive adhesive layer 130 completely covers the bonding electrode exposed region 128 of the bonding electrode 116 that is not covered by the second substrate 104, the insulating layer 118 and the circuit board electrode 142, in other words, in the present invention In the above bonding structure, the anisotropic conductive adhesive layer 130 also serves as a bonding electrode protection layer and completely covers the bonding electrodes 116 in the bonding region 120 . Therefore, in addition to the strong bonding strength of the bonding structure described in the present invention, the anisotropic conductive adhesive layer 130 completely covers the bonding electrodes to isolate the contact with the outside world. The formed bonding electrodes can isolate the bonding electrodes from the atmosphere without adding other adhesive materials, thereby increasing the stability of the product. In addition, the anisotropic conductive adhesive layer 130 can also be connected to each other, as shown in FIG. 4B ; and the bonding structure of the bonding electrode and the circuit board electrode described in the present invention is also suitable for insulating layers with non-linear edges. 118, as shown in Figure 4C.

Please refer to FIG. 6A to FIG. 6C , which are schematic cross-sectional views of other preferred embodiments of the present invention. Wherein the anisotropic conductive adhesive layer 130 completely covers the bonding electrode 116, and the anisotropic conductive adhesive layer 130 may further cover the insulating layer 118 or the circuit board 140, as shown in FIG. 6A; On the one hand, in the bonding structure of the present invention, the anisotropic conductive adhesive layer 130 can also completely overflow a first interface 115, as shown in FIG. 6B, wherein the first interface 115 includes the first substrate The boundary 113 is perpendicular to the plane of the circuit board electrode 142 ; on the other hand, the anisotropic conductive adhesive layer 130 can also partially overflow the first interface 115 , as shown in FIG. 6C . In this way, the bonding electrode 116 and the circuit board electrode 142 will have optimal bonding strength.

In another preferred embodiment of the present invention, please refer to FIG. 7 for the bonding structure of the bonding electrode and the circuit board electrode described in the present invention. An adhesive material 134 can also be added to the anisotropic conductive adhesive layer and The circuit board electrode is used to prevent the infiltration of water vapor. The bonding structure of the above-mentioned plasma display can reduce the migration of silver atoms (Ag migration), thereby avoiding the phenomenon of short circuit of bonding electrodes, and is especially suitable for bonding electrodes formed by thick film process.

The preferred embodiment described above takes the bonding structure of the first substrate 102 as an example. Similarly, the bonding structure of bonding electrodes and circuit board electrodes described in the present invention is also applicable to the bonding structure corresponding to the first substrate 102. The bonding structure of the two substrates 104 .

Please refer to FIG. 8, which shows a perspective view of a flat panel display device 200 according to the bonding structure of the present invention, wherein the first substrate 102 can be a front substrate, and the second substrate 104 can be a rear substrate . It can be clearly seen from the figure that the bonding structure described in the present invention is also applicable to the connection between the front substrate or the rear substrate and the corresponding circuit board. Wherein, the circuit board 140 may be a flexible printed circuit (FPC).

The bonding structure of bonding electrodes and circuit board electrodes described in the present invention is not only suitable for plasma display devices, improving the bonding strength between its substrate and external circuits, but also suitable for other devices that need to be bonded with additional circuits. Flat panel display devices, such as liquid crystal displays and organic light emitting displays, are applicable to the bonding structure described in the present invention.

Although the present invention is disclosed above in conjunction with preferred embodiments, it is not intended to limit the scope of the present invention. Any person skilled in the art may make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention shall prevail as defined by the appended claims.

Claims (19)

1. the bonding structure of bonding electrode and circuit board electrode comprises:

One first substrate, this first substrate has a first surface;

A plurality of bonding electrodes, these a plurality of bonding electrodes are formed on the first surface of this first substrate with a second surface, and this bonding electrode has one the 3rd surface in the opposition side of this second surface, wherein these a plurality of bonding electrodes have the bonding region in the edge of first substrate, and a nonbonding district;

One anisotropic conductive gluing layer is formed on the 3rd surface of the first surface of this first substrate and this bonding electrode, and covers this bonding region fully; And

Circuit board with at least one circuit board electrode, be formed on this anisotropic conductive gluing layer, wherein this circuit board electrode is fixed on the corresponding bonding electrode with this anisotropic conductive gluing layer, and between this circuit board electrode bonding electrode corresponding with this with this anisotropic conductive gluing layer driving fit.

2. the bonding structure of bonding electrode as claimed in claim 1 and circuit board electrode wherein also comprises a glue material and is formed on this anisotropic conductive gluing layer and this circuit board electrode.

3. the bonding structure of bonding electrode as claimed in claim 1 and circuit board electrode also comprises in the nonbonding district on the 3rd surface that an insulation course is formed at these a plurality of bonding electrodes.

4. the bonding structure of bonding electrode as claimed in claim 3 and circuit board electrode, wherein this insulation course is a dielectric material.

5. the bonding structure of bonding electrode as claimed in claim 1 and circuit board electrode also comprises on part the 3rd surface that one second substrate is formed at these a plurality of bonding electrodes, and exposes this bonding region.

6. the bonding structure of bonding electrode as claimed in claim 1 and circuit board electrode, wherein the outward extending border of this first surface is one first boundary line, be positioned at this corresponding position of first boundary line and this circuit board electrode has one second boundary line, and this anisotropic conductive gluing layer exceeds one first interface that comprises this first boundary line and this second boundary line between the part of this circuit board electrode and this bonding electrode along normal direction in circuit board electrode.

7. the bonding structure of bonding electrode as claimed in claim 1 and circuit board electrode, wherein this anisotropic conductive gluing layer is an anisotropy conductiving glue.

8. the bonding structure of bonding electrode as claimed in claim 1 and circuit board electrode, wherein this circuit board is a flexible PCB.

9. flat display apparatus comprises:

One first substrate, this first substrate has a first surface;

A plurality of bonding electrodes, these a plurality of bonding electrodes are formed on the first surface of this first substrate with a second surface, and this bonding electrode has one the 3rd surface in the opposition side of this second surface;

One second substrate covers on part the 3rd surface of these a plurality of bonding electrodes, and the 3rd surface that is not covered by this second substrate comprises a bonding region and a nonbonding district;

One anisotropic conductive gluing layer is formed on the 3rd surface of the first surface of this first substrate and this bonding electrode, and covers this bonding region fully; And

Circuit board with at least one circuit board electrode, be formed on this anisotropic conductive gluing layer, wherein this circuit board electrode is fixed on the corresponding bonding electrode with this anisotropic conductive gluing layer, and between this circuit board electrode bonding electrode corresponding with this with this anisotropic conductive gluing layer driving fit

Wherein one of this first substrate and this second substrate person is the front board structure of a flat display apparatus, and another person is the back plate structure of a flat display apparatus.

10. flat display apparatus as claimed in claim 9, wherein this bonding electrode is a thick membrane electrode.

11. flat display apparatus as claimed in claim 9, wherein this bonding electrode is one to contain silver electrode.

12. flat display apparatus as claimed in claim 9 wherein also comprises a glue material and is formed on this anisotropic conductive gluing layer and this circuit board electrode.

13. flat display apparatus as claimed in claim 9, wherein this bonding electrode is a membrane electrode.

14. flat display apparatus as claimed in claim 9, wherein the material of this bonding electrode is selected in the alloy of free chromium, copper, aluminium, nickel, tungsten and cobalt or the group that laminated thing is formed.

15. flat display apparatus as claimed in claim 9 also comprises in the nonbonding district on the 3rd surface that an insulation course is formed at these a plurality of bonding electrodes.

16. flat display apparatus as claimed in claim 9, wherein this insulation course is a dielectric material.

17. flat display apparatus as claimed in claim 9, wherein the outward extending border of this first surface is one first boundary line, be positioned at this corresponding position of first boundary line and this circuit board electrode has one second boundary line, and this anisotropic conductive gluing layer exceeds one first interface that comprises this first boundary line and this second boundary line between the part of this circuit board electrode and this bonding electrode along normal direction in circuit board electrode.

18. flat display apparatus as claimed in claim 9, wherein this anisotropic conductive gluing layer is an anisotropy conductiving glue.

19. flat display apparatus as claimed in claim 9, wherein this circuit board is a flexible PCB.

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