TW202028940A - Curved surface self-alignment bonding device and method thereof - Google Patents

Abstract

The invention provides a curved surface self-alignment bonding device and method thereof, which comprises:a touch sensing layer, a flexible printed circuit board and a self-polymerizing resin. The touch sensing layer has a plurality of lower electrodes. The flexible printed circuit board and the touch sensing layer are disposed corresponding to each other, and the flexible printed circuit board has a plurality of upper electrode faces for the plurality of lower electrodes of the touch sensing layer. The self-polymerizing resin comprises a plurality of metal alloy particle spheres and a thermosetting polymer glue uniformly disposed between the touch sensing layer and the flexible printed circuit board. When pressing down the upper electrode of the flexible printed circuit board, the temperature of the self-assembly paste is increased by a heating method, make the metal alloy particles is melted, then the molten metal alloy particles will collecte between the upper electrode and the lower electrode, completed the bonding of the upper electrode and the lower electrode.The present invention also comprises a curved surface self-alignment bonding method.

Description

Surface self-aligning joining device and method

The invention relates to a curved surface joining technology.

Despite the evolution of the times, touch screens have gradually replaced buttons on products, and in response to the rapid development of in-vehicle systems and wearable systems, the development of curved touch screens is imperative in order to meet modern people's pursuit of fashion trends. Due to the demand for curved touch screens, the protective glass and touch sensing layer on the touch panel must also be designed to be curved when designing the panel. In the previous "curved surface pressing" technology, first design a The pulse-type indenter and fixture that protect the curvature of the glass and the touch sensing layer are used to connect the flexible printed circuit (FPC) and the touch sensing layer through anisotropic conductive film (ACF) The pressing is performed directly in the curved surface, so that the upper and lower electrodes can be connected and conducted without extending the bonding pad, which brings benefits to the manufacturing process and products.

Although the above method can bring some slight benefits to the process, however, during the pressing process of ACF, the overlap area of the upper and lower electrodes must reach at least 2/3 of the electrode, and the overlap area must deform at least 5 conductive particles by 20% ~60% can achieve a good conduction rate. This flat-to-curve pressing may cause offset due to the different focal lengths during the pressing process. Even if the front end is slightly bent when making FPC, it may be inaccurate. Moreover, it is not easy to manufacture the biaxial bending indenter. A slight deviation in the manufacture may result in uneven pressure distribution during pressing, and even lead to uneven deformation of the conductive particles in the ACF, resulting in poor conductivity. Therefore, in order to solve the above-mentioned conventional problems and deficiencies, the present invention proposes a curved surface self-alignment joining technology, which can solve the current situation that the upper and lower electrodes cannot get good contact due to misalignment.

Based on the above, those with ordinary knowledge in the field should understand that if future users have higher requirements for curved displays or curved touch panels, such as biaxial bends, multiaxial bends, or other more complex combinations of curved surfaces, Today’s ACF pressing will face more and more challenges, and may even be unsuitable. Therefore, the inventor of the present invention, in view of solving the deficiencies or deficiencies in ACF pressing, has made multiple evaluations and considerations, and has accumulated experience in this industry. With many years of experience, he designed this kind of invention patentee.

The present invention provides a self-alignment bonding device for curved surfaces, comprising: a touch sensing layer with a plurality of lower electrodes; a flexible printed circuit board arranged corresponding to the touch sensing layer, with a plurality of upper electrode surfaces facing each other The plurality of bottom electrodes of the touch sensing layer; a self-polymerizing resin, including a plurality of metal alloy particle balls and a thermosetting polymer glue, evenly arranged between the touch sensing layer and the flexible printed circuit board; When pressing down directly above the upper electrode of the flexible printed circuit board, the temperature of the self-polymerizing resin rises through heating. When the temperature of the self-polymerizing resin rises, the metal alloy particle ball is melted, and the molten metal The alloy particle balls gather between the upper electrode and the lower electrode to align and conduct the upper electrode and the lower electrode. The thermosetting polymer glue further solidifies as the temperature rises to complete the connection between the upper electrode and the lower electrode. Splice.

The present invention provides a curved surface self-alignment bonding method, which includes the following steps: S1: providing a touch sensing layer, which is arranged on a protective cover, and the edge of the touch sensing layer has a bottom electrode; S2: providing a cover, Located directly above the touch sensing layer, and the bottom electrode surface faces the cover plate; S3: Provides a flexible printed circuit board, located between the cover plate and the bottom electrode of the touch sensing layer, and has an upper electrode surface for the touch The bottom electrode at the edge of the sensing layer; S4: Provide self-polymerizing resin, including metal alloy particle balls and thermosetting polymer glue, evenly coated between the upper electrode and the bottom electrode; S5: Make the cover facing the flexible printed circuit board When the cover is pressed directly above the upper electrode of the flexible printed circuit board, the temperature of the self-polymerizing resin rises through heating; S6: When the temperature of the self-polymerizing resin rises, the metal The alloy particle ball melts, and the molten metal alloy particle ball gathers between the upper electrode and the lower electrode to align and conduct the upper electrode and the lower electrode. The thermosetting polymer glue further solidifies as the temperature rises to complete the upper electrode and the lower electrode.的连接。 Joining.

Preferably, the metal alloy particle ball contains tin-bismuth alloy, etc., a metal alloy with self-aggregating properties in the molten state.

Preferably, the thermosetting polymer glue includes polyacrylic resin glue, amino resin glue, furan resin glue, phenolic resin glue, unsaturated polyester glue, silicone resin glue, polyurethane glue, resorcinol-formaldehyde resin glue, Any one or a combination of polyimide glue, melamine silicone resin glue, xylene-formaldehyde resin glue, urea-formaldehyde resin glue, silicone plastic, polydiacrylophthalate glue, epoxy glue .

Preferably, the touch sensing layer and the flexible printed circuit board can be corresponding flexible curved surfaces or flat surfaces.

Preferably, the touch sensing layer and the flexible printed circuit board may be a flexible curved surface or a flat surface that is not completely opposed.

Preferably, the flexible curved surface includes a multi-curvature surface or a single-curvature surface.

Preferably, the cover includes a surface of the cover, wherein the surface of the cover includes a surface with the same curvature structure as the touch sensing layer and the flexible printed circuit board.

Among them, when the cover plate is pressed down directly above the upper electrode of the flexible printed circuit board, the temperature of the self-polymerizing resin rises through heat conduction, causing the metal alloy particle ball to melt, and the molten metal alloy particle ball faces between the upper electrode and the lower electrode. Assemble, so that the upper electrode and the lower electrode are aligned and connected, and the thermosetting polymer glue is further cured as the temperature rises to complete the connection of the upper electrode and the lower electrode.

In order to achieve the above objectives and effects, the technical means and structure adopted by the present invention are drawn to illustrate the characteristics and functions of the preferred embodiments of the present invention in detail. The size of the coating and the range can be exaggerated, so as to fully understand it, but should It is understood that such content does not constitute a limitation of the present invention.

Referring to FIG. 1, it is a schematic diagram of an implementation of a self-aligning joining device for curved surfaces of the present invention. A curved surface self-aligning bonding device includes: a touch sensing layer 10, a flexible printed circuit board 20, and a self-polymerizing resin 50.

The touch sensing layer 10 has a plurality of bottom electrodes 11.

The flexible printed circuit board 20 and the touch sensing layer 10 are disposed corresponding to each other, and have a plurality of upper electrodes 21 facing the plurality of lower electrodes 11 of the touch sensing layer 10.

The self-polymerizing resin 50 includes a plurality of metal alloy particle balls 51 and a thermosetting polymer glue 52, which are evenly disposed between the touch sensing layer 10 and the flexible printed circuit board 20.

When pressing down directly above the upper electrode 21 of the flexible printed circuit board 20, the temperature of the self-polymerizing resin 50 is increased by heating. When the temperature of the self-polymerizing resin 50 rises, the metal alloy particle ball 51 Melting, the molten metal alloy particle ball 51 gathers between the upper electrode 21 and the lower electrode 11, so that the upper electrode 21 and the lower electrode 11 are aligned and connected. The thermosetting polymer glue 52 increases with the temperature Further curing completes the joining of the upper electrode 21 and the lower electrode 11.

Please refer to Figure 1 and Figure 2 at the same time. Figure 2 is a schematic diagram of the layering of a curved touch panel. It can be seen from the figure that the curved touch panel can include a protective layer 12 and a touch sensing layer 10, and has a decorative layer 13 interposed between the protective layer 12 and the touch-sensing layer 10, wherein a lower electrode 11 is provided at the edge of the touch-sensing layer 10 for joining the upper electrode 21 of the flexible printed circuit board 20.

Referring to FIG. 3, it is a flowchart of the steps of the curved surface joining method according to the present invention. First step S1: provide the touch sensing layer, which is arranged on the protective layer 12, and the bottom electrode 11 is provided at the edge of the touch sensing layer 10; then step S2: provide the cover plate 30, which is located in front of the touch sensing layer 10. And the bottom electrode 11 faces the cover plate 30; then step S3: provide a flexible printed circuit board 20 between the cover plate 30 and the bottom electrode 11 of the touch sensing layer 10, and has the top electrode 21 facing the contact Control the bottom electrode at the edge of the sensing layer 10; then step S4: Provide a self-assembled resin 50 (Self-Assembly Paste, SAP), including metal alloy particle balls 51 and thermosetting polymer glue 52, uniformly coated on the top electrode 21 And the lower electrode 11; then step S5: press the cover plate toward the upper electrode 21 of the flexible printed circuit board 20, when the cover plate 30 is pressed toward the upper electrode 21 of the flexible printed circuit board 20, The temperature of the self-polymerizing resin 50 is increased by heating; the final step S6: when the temperature of the self-polymerizing resin 50 rises, the metal alloy particle ball 51 is melted, and the molten metal alloy particle ball 51 faces between the upper electrode 21 and the lower electrode 11 In order to align and conduct the upper electrode 21 and the lower electrode 11, the thermosetting polymer glue 52 further solidifies as the temperature rises to complete the bonding of the upper electrode and the lower electrode.

In summary, the above steps will be described in detail below.

4, in order to realize the schematic diagram of the bonding jig according to the embodiment of the present invention, the bonding jig has a placement plane 40 for placing the curved touch panel and a cover plate 30 on which the curved touch panel is placed on the placement plane 40. And the bottom electrode 11 of the touch sensing layer 10 faces the cover plate 30, and then the flexible printed circuit board 20 with the upper electrode 21 is placed between the cover plate 30 and the touch sensing layer 10, and the flexible printed circuit board The upper electrode 21 of 20 faces the lower electrode 11 of the touch sensing layer 10, where the upper electrode and the lower electrode contain any one of gold, silver, copper, tin, etc., or alloys containing the above materials, and then provide a joint development with Sekisui Chemical The self-polymerizing resin 50 is uniformly coated between the lower electrode 11 and the upper electrode 21, and finally the cover plate 30 is pressed down, so that the upper electrode 21 of the flexible printed circuit board 20 is pressed down to the lower electrode of the touch sensing layer 10 11. Those with ordinary knowledge in the art should understand that this joint jig is only a detailed description of the spirit and scope of the present invention, and is not a limitation of the present invention.

5(a) to 5(b), which are schematic diagrams of the downward pressure of the curved surface joining method of the present invention. It can be seen from the figures that the self-polymerizing resin 50 may include metal alloy particle balls 51 and thermosetting polymer glue 52, wherein the metal alloy The particle balls 51 are uniformly distributed in the thermosetting polymer glue 52. The metal alloy particle balls 51 may include tin-bismuth alloy particle balls and other alloy metals that have the ability to self-polymerize in the molten state, and the thermosetting polymer glue 52 may include polyacrylic resin. Glue, amino resin glue, furan resin glue, phenolic resin glue, unsaturated polyester glue, silicone resin glue, polyurethane glue, resorcinol-formaldehyde resin glue, polyimide glue, melamine resin glue , Xylene-formaldehyde resin glue, urea-formaldehyde resin glue, silicone plastic, poly-diacrylate phthalate glue, epoxy resin glue and other related thermosetting materials. When the cover plate 30 is pressed down, the temperature of the self-polymerizing resin 50 is increased through a heating method. The heating method can include heat conduction, laser heating or reflow furnace, etc., any of which can increase the temperature of the self-polymerizing resin 50 The heating method of the present invention has been used as an example to illustrate the spirit and scope of the present invention.

6 is a binary metallographic diagram of the tin-bismuth alloy particle ball 51 according to the embodiment of the present invention. In the figure, the dotted line on the left is the tin liquidus, the dotted on the right is the bismuth liquidus, and the solid line is the tin-bismuth The binary metallurgical line of the alloy, the area A in the figure shows the common phase area of tin and bismuth, and the area B in the figure shows the tin-rich solid solution area. It can be seen from the figure that when the weight percentage concentration of tin is 100%, its melting point is 231.9℃ , And when the weight percent concentration of bismuth is 100%, its melting point is 271.4°C. As the weight percentage concentration of bismuth in tin becomes higher and higher, the melting point of tin becomes lower and lower. Conversely, when the weight percentage concentration of tin in bismuth becomes higher and higher, the melting point of bismuth becomes lower and lower. At 57%, the melting points of tin and bismuth cross at 139°C, and the tin-bismuth alloy enters the tin-bismuth common phase. Therefore, it can be seen that the tin-bismuth alloy particle ball 51 has a weight percentage of 43% and 57%, respectively. When heated to 139°C, the tin-bismuth alloy particle ball 51 forms a eutectic structure, and many alloys have similar properties.

7(a) and 7(b), which are the top view of the OM (Optical Microscope) and the SEM (Scanning Electron Microscope, SEM) cross-sectional view of the electrode bonding surface of the present invention after planar bonding. The SAP50 (Self- Assembly Paste) is evenly coated between the upper electrode 21 and the lower electrode 11 (the two electrodes overlap in the figure) before heating and pressing, and then as the temperature of the SAP50 rises to 139°C, refer to Figure 6(c) 6(d) is a plan view and a cross-sectional view of the electrode joint surface taken by SEM after the curved surface of the present invention is joined. It can be seen from FIG. 6(c) that the tin-bismuth alloy particle ball 51 in the SAP50 faces the upper electrode 21 and the lower electrode 21 It can be seen from Figure 6(d) that the tin-bismuth alloy particle balls 51 not only gather between the upper electrode 21 and the lower electrode 11, but also align the upper electrode 21 and the lower electrode 11 up and down. It is joined, and finally the thermosetting polymer glue 52 in the SAP50 is cured to complete the joining, and then the self-aligning joining of the curved surfaces is completed.

From the above method, the temperature of the SAP 50 rises to 139°C by heating during the pressing process, so the tin-bismuth alloy particle ball 51 in the SAP 50 is in a molten state. The conventional ACF bonding method, if encountered If the deflection is different or the electrodes are not accurately aligned, it will not be easy to crush and deform the conductive particles in the ACF to cause the upper and lower electrodes to be connected. Therefore, the curved self-alignment bonding method proposed by the present invention is more adaptable than ACF. Deflection of curved surface joints.

Through the above detailed description, the purpose and effect of the present invention can be fully demonstrated. The above description only clearly illustrates the spirit and scope of the present invention, and does not limit the present invention. Therefore, those with ordinary knowledge in the art should understand that all applications Equivalent replacements and obvious changes made in the description and illustrations of the present invention are all included in the protection scope of the present invention.

10: Touch sensing layer 11: Lower electrode 12: protective layer 13: decorative layer 20: Flexible printed circuit board 21: Upper electrode 30: cover 40: Place a plane 50: Self-polymerizing resin 51: Metal alloy particle ball 52: Thermosetting polymer glue S1-S6: steps

FIG. 1 is a schematic diagram of the implementation of the self-aligning joining device for curved surfaces of the present invention.

Figure 2 is a schematic diagram of the layering of the curved touch panel.

Figure 3 is a flow chart of the steps of the curved surface joining method of the present invention.

Fig. 4 is a schematic diagram of a joining jig implementing an embodiment of the present invention.

Figures 5(a) to 5(b) are schematic diagrams of the downward pressing of the curved surface joining method of the present invention.

Fig. 6 is a binary metallographic diagram of a tin-bismuth alloy particle ball according to an embodiment of the present invention.

FIG. 7(a) is a top view of an optical microscope (OM) of the electrode bonding surface after planar bonding of the present invention.

Fig. 7(b) is a cross-sectional view of an electrode taken by a scanning electron microscope (Scanning Electron Microscope, SEM) of the electrode joining surface after planar joining of the present invention.

Fig. 7(c) is a top view of the optical microscope (OM) of the electrode joint surface after the curved surface joint of the present invention

Fig. 7(d) is a cross-sectional view of the electrode taken by the scanning electron microscope (Scanning Electron Microscope, SEM) of the electrode joining surface after the curved surface joining of the present invention.

10: Touch sensing layer

11: Lower electrode

12: protective layer

20: Flexible printed circuit board

21: Upper electrode

50: Self-polymerizing resin

51: Metal alloy particle ball

52: Thermosetting polymer glue

Claims (10)

A curved surface self-aligning joining device, including: A touch sensing layer having a plurality of bottom electrodes; A flexible printed circuit board, which is arranged corresponding to the touch sensing layer, and has a plurality of upper electrode surfaces facing the plurality of lower electrodes of the touch sensing layer; A self-polymerizing resin, including a plurality of metal alloy particle balls and a thermosetting polymer glue, evenly arranged between the touch sensing layer and the flexible printed circuit board; When pressing down directly above the upper electrode of the flexible printed circuit board, the temperature of the self-polymerizing resin rises through heating. When the temperature of the self-polymerizing resin rises, the metal alloy particle ball is melted and the molten Metal alloy particle balls gather between the upper electrode and the lower electrode to align and conduct the upper electrode and the lower electrode. The thermosetting polymer glue further solidifies as the temperature rises to complete the upper electrode and the lower electrode的连接。 Joining. A self-alignment joining method for curved surfaces, which includes the following steps: S1: Provide a touch sensing layer, which is arranged on the protective cover, and the edge of the touch sensing layer has a bottom electrode; S2: Provide a cover plate, which is located directly above the touch sensing layer, and the bottom electrode surface faces the cover plate; S3: providing a flexible printed circuit board, located between the cover plate and the bottom electrode of the touch sensing layer, and having an upper electrode surface facing the bottom electrode at the edge of the touch sensing layer; S4: Provide a self-polymerizing resin, including metal alloy particle balls and thermosetting polymer glue, uniformly coated between the upper electrode and the lower electrode; S5: Press the cover plate directly above the upper electrode of the flexible printed circuit board. When the cover plate is pressed down directly above the upper electrode of the flexible printed circuit board, the self-aggregating resin is heated The temperature rises; S6: When the temperature of the self-polymerizing resin rises, the metal alloy particle ball is caused to melt, and the molten metal alloy particle ball gathers between the upper electrode and the lower electrode, so as to align the upper electrode and the lower electrode. When turned on, the thermosetting polymer glue further solidifies as the temperature rises to complete the bonding of the upper electrode and the lower electrode. According to the self-alignment joining method for curved surfaces as described in item 2 of the scope of patent application, the metal alloy particle ball comprises a tin-tin-bismuth alloy. As described in the second item of the scope of patent application, the curved surface self-alignment bonding method, wherein the thermosetting polymer glue includes polyacrylic resin glue, amino resin glue, furan resin glue, phenolic resin glue, unsaturated polyester glue, silicone resin Glue, polyurethane glue, resorcinol-formaldehyde resin glue, polyimide glue, triamine silicone resin glue, xylene-formaldehyde resin glue, urea-formaldehyde resin glue, silicone plastic, polyphthalic acid two Any one or a combination of acrylic glue and epoxy glue. As described in the second item of the scope of patent application, the self-alignment joining method for curved surfaces, wherein the heating method is one of heat conduction, laser heating or reflow furnace. The curved surface self-alignment bonding method described in the second item of the scope of patent application, wherein the touch sensing layer and the flexible printed circuit board are correspondingly a flexible curved surface or a flat surface. According to the self-alignment bonding method for curved surfaces as described in item 2 of the scope of patent application, the touch sensing layer and the flexible printed circuit board are a flexible curved surface or a flat surface that is not completely opposed. According to the self-alignment joining method of curved surfaces described in item 6 or item 7 of the scope of patent application, the flexible curved surface includes a multi-curvature surface or a single-curvature surface. The curved surface self-alignment joining method described in item 8 of the scope of patent application, wherein the cover plate includes a cover plate surface. According to the curved surface self-alignment bonding method described in claim 9, wherein the surface of the cover includes a surface with the same curvature structure as the touch sensing layer and the flexible printed circuit board.

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