Fingerprint side key for electronic device

Abstract

The application discloses a fingerprint side key for electronic equipment, which is installed on an electronic equipment shell and comprises a flexible circuit substrate and a body provided with a fingerprint identification chip. One side surface of one end of the flexible circuit substrate is electrically connected with the fingerprint identification chip on the body. Each first chip pad and a corresponding first substrate pad and each second substrate pad and a corresponding second chip pad are connected through tin paste welding, so that a gap layer is formed between the flexible circuit substrate and the chip, and a communicating gap flow channel is formed between adjacent first substrate pads and between adjacent first substrate pads and second substrate pads. A glue layer filled in the gap flow channel is wrapped outside the welding points between the first chip pads and the first substrate pads. The application improves the overall structural strength and waterproof and dustproof performance and avoids corrosion of the pads and the welding points by chemical medicine water in subsequent reliability test processes.

Description

Technical Field

[0001] This invention relates to a fingerprint side button for electronic devices, belonging to the field of electronic device structure technology. Background Technology

[0002] With the rapid development of the mobile internet era, mobile phones have become more integrated with various functions. Today, mobile phone screen sizes have reached a critical point. In pursuit of better visual effects, another form of design innovation—the full-screen display—has emerged. The arrival of the full-screen display inevitably leads to a revolution in fingerprint recognition technology. One design solution is to place the fingerprint recognition component on the side of the phone, creating a side-mount fingerprint sensor. However, due to the smaller size of the side-mount fingerprint chip, surface-mount technology (SMT) is used to solder the chip onto the circuit board, which can easily result in poor waterproofing of the soldered components. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide a fingerprint side button for electronic devices, which not only improves the overall structural strength and waterproof and dustproof performance, but also avoids corrosion of the solder pads and solder joints by chemical solutions during subsequent reliability testing and other processes.

[0004] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is: a fingerprint side button for an electronic device, comprising: a flexible circuit board and a body containing a fingerprint recognition chip, wherein one side surface of one end of the flexible circuit board is electrically connected to the fingerprint recognition chip on the body, a plurality of first substrate pads are provided in the middle region of the flexible circuit board facing the fingerprint recognition chip, and at least one second substrate pad is provided on each side of the first substrate pads and at both ends of the flexible circuit board, and a plurality of first chip pads corresponding to the first substrate pads and second chip pads corresponding to the second substrate pads are provided on the side of the fingerprint recognition chip facing the flexible circuit board; The area of ​​the first chip pad is larger than the area of ​​the first substrate pad directly below it. The area of ​​the second chip pad is the same as that of the second substrate pad. Each first chip pad is connected to its corresponding first substrate pad, and each second substrate pad is connected to its corresponding second chip pad by solder paste. This forms a gap layer between the flexible circuit board and the chip, and a connecting gap channel is formed between adjacent first substrate pads and between adjacent first substrate pads and second substrate pads. An adhesive layer filled in the gap channel covers the outside of the solder joint between the first chip pad and the first substrate pad.

[0005] The following are further improvements to the above technical solution: 1. In the above scheme, the first substrate pad, the second substrate pad, the first chip pad, and the second chip pad are all rectangular pads.

[0006] 2. In the above scheme, the length of each first chip pad is greater than the length of the first substrate pad located directly below it.

[0007] 3. In the above scheme, the adhesive layer is an epoxy adhesive layer.

[0008] 4. In the above scheme, the two opposite side surfaces of the adhesive layer are flush with the side surfaces of the flexible circuit board.

[0009] 5. In the above scheme, a plurality of the first substrate pads are arranged at equal intervals along the length direction of the flexible circuit substrate.

[0010] 6. In the above scheme, a plurality of first substrate pads are arranged in two rows, and multiple first substrate pads in each row are equally spaced along the length direction of the flexible circuit substrate.

[0011] 7. In the above scheme, the flexible circuit board has a plurality of grooves on its surface facing the fingerprint recognition chip, and the surface of the first substrate pad embedded in the groove is lower than the surface of the flexible circuit board.

[0012] Due to the application of the above technical solution, the present invention has the following advantages compared with the prior art: This invention relates to a fingerprint side button for an electronic device. While achieving fingerprint recognition and physical pressure control, the flexible circuit board has several first substrate pads in the central region facing the fingerprint recognition chip. At least one second substrate pad is located on each side of the first substrate pads and at each end of the flexible circuit board. The fingerprint recognition chip has several first chip pads corresponding to the first substrate pads and several second chip pads corresponding to the second substrate pads on the side facing the flexible circuit board. The area of ​​the first chip pads is larger than the area of ​​the first substrate pad directly below them. The areas of the second chip pads are the same as the second substrate pads. A gap layer is formed between the flexible circuit board and the chip, and adjacent first substrate pads and adjacent first substrate pads are separated by a gap layer. A connecting gap channel is formed between the two substrate pads. An adhesive layer filled in the gap channel covers the outside of the solder joint between the first chip pad and the first substrate pad. By setting the pad size differently, the chip position can be avoided from shifting and affecting the soldering accuracy during the heating and cooling process. It can also prevent the flux in the solder paste from overflowing when it melts at high temperature and then solidifying when it cools down and blocking the adhesive channel. Through a simple single-sided adhesive injection process, the gap layer and gap channel can be fully filled, which not only improves the overall structural strength and waterproof and dustproof performance of the fingerprint side key, but also prevents the pads and solder joints from being corroded by chemical solutions during subsequent reliability testing and other processes, thus improving the overall weather resistance and reliability of the fingerprint side key for electronic devices. Attached Figure Description

[0013] Appendix Figure 1 This is a schematic diagram of the structure of the fingerprint side button for the electronic device of the present invention; Appendix Figure 2 This is an exploded view of the structure of the fingerprint side button for the electronic device of the present invention; Appendix Figure 3 A partial cross-sectional view of the fingerprint side button for the electronic device of the present invention. Figure 1 ; Appendix Figure 4 A partial cross-sectional view of the fingerprint side button for the electronic device of the present invention. Figure 1 ; Appendix Figure 5 This is a partial structural schematic diagram of the flexible circuit board in the fingerprint side key of the electronic device of the present invention.

[0014] In the above figures: 1. Flexible circuit board; 11. First substrate pad; 12. Second substrate pad; 13. Groove; 2. Fingerprint recognition chip; 21. First chip pad; 22. Second chip pad; 3. Gap layer; 31. Gap channel; 4. Adhesive layer; 5. Connector; 6. Cover plate; 7. Reinforcing plate; 8. Elastic support; 91. Positioning protrusion; 92. Positioning hole; 10. Pressing protrusion. Detailed Implementation

[0015] In the description of this patent, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used solely for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. The terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance. Furthermore, unless otherwise explicitly specified and limited, the terms "installed," "connected," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this patent based on the specific circumstances.

[0016] Example 1: A fingerprint side button for an electronic device, installed on the housing of the electronic device, includes: a flexible circuit board 1 and a body containing a fingerprint recognition chip 2. One side surface of one end of the flexible circuit board 1 is electrically connected to the fingerprint recognition chip 2 on the body 2, and a reinforcing plate 7 is connected to the other side surface opposite to the fingerprint recognition chip 2. The other end of the flexible circuit board 1 is equipped with a connector 5 for connecting to the motherboard of the electronic device. The flexible circuit board 1 has a plurality of first substrate pads 11 in the middle region facing the fingerprint recognition chip 2. At least one second substrate pad 12 is provided on each side of the first substrate pad 11 and at each end of the flexible circuit board 1. The fingerprint recognition chip 2 has a plurality of first chip pads 21 corresponding to the first substrate pads 11 and second chip pads 22 corresponding to the second substrate pads 12 on the side facing the flexible circuit board 1. The area of ​​the first chip pad 21 is larger than the area of ​​the first substrate pad 11 located directly below it, and the area of ​​the second chip pad 22 is the same as that of the second substrate pad 12. Each first chip pad 21 is soldered to its corresponding first substrate pad 11, and each second substrate pad 12 is soldered to its corresponding second chip pad 22, so that a gap layer 3 is formed between the flexible circuit substrate 1 and the chip 2, and a communicating gap channel 31 is formed between adjacent first substrate pads 11 and between adjacent first substrate pads 11 and second substrate pads 12. An adhesive layer 4 filled in the gap channel 31 covers the outside of the solder joint between the first chip pad 21 and the first substrate pad 11.

[0017] The first substrate pad 11, the second substrate pad 12, the first chip pad 21, and the second chip pad 22 are all rectangular pads; the length of each of the first chip pads 21 is greater than the length of the first substrate pad 11 located directly below it. Several of the aforementioned first substrate pads 11 are arranged in two rows, and multiple first substrate pads 11 in each row are equally spaced along the length of the flexible circuit board 1; the aforementioned connector 5 is used for electrical connection with the motherboard of the electronic device. The reinforcing plate 7 is a steel plate; the fingerprint recognition chip 2 and the connector 5 are respectively connected to the surfaces on both sides of the flexible circuit board 1; a plurality of grooves 13 are formed on the surface of the flexible circuit board 1 facing the fingerprint recognition chip 2, and the surface of the first substrate pad 11 embedded in the groove 13 is lower than the surface of the flexible circuit board 1. An elastic support 8 is connected to the surface of the reinforcing plate 7 opposite to the flexible circuit board 1; the elastic support 8 is a TPU support; the elastic support 8 is bonded to the reinforcing plate 7; a pressing protrusion 10 is provided on the side of the elastic support 8 opposite to the reinforcing plate 7, and the pressing protrusion 10 is used for the pressing contact of the power button of the electronic device. The elastic support member 8 and the reinforcing plate 7 are connected by at least one set of positioning protrusions 91 and positioning holes 92; the positioning protrusions 91 are located on the surface of the elastic support member 8 facing the reinforcing plate 7, and the positioning holes 92 are formed on the reinforcing plate 7.

[0018] Example 2: A fingerprint side button for an electronic device, comprising: a flexible circuit board 1 and a body equipped with a fingerprint recognition chip 2, wherein one side surface of one end of the flexible circuit board 1 is electrically connected to the fingerprint recognition chip 2 on the body 2. The flexible circuit board 1 has a plurality of first substrate pads 11 in the middle region facing the fingerprint recognition chip 2. At least one second substrate pad 12 is provided on each side of the first substrate pad 11 and at each end of the flexible circuit board 1. The fingerprint recognition chip 2 has a plurality of first chip pads 21 corresponding to the first substrate pads 11 and second chip pads 22 corresponding to the second substrate pads 12 on the side facing the flexible circuit board 1. The area of ​​the first chip pad 21 is larger than the area of ​​the first substrate pad 11 located directly below it, and the area of ​​the second chip pad 22 is the same as that of the second substrate pad 12. Each first chip pad 21 is soldered to its corresponding first substrate pad 11, and each second substrate pad 12 is soldered to its corresponding second chip pad 22, so that a gap layer 3 is formed between the flexible circuit substrate 1 and the chip 2, and a communicating gap channel 31 is formed between adjacent first substrate pads 11 and between adjacent first substrate pads 11 and second substrate pads 12. An adhesive layer 4 filled in the gap channel 31 covers the outside of the solder joint between the first chip pad 21 and the first substrate pad 11.

[0019] The adhesive layer 4 is an epoxy adhesive layer; the two opposite side ends of the adhesive layer 4 are flush with the side ends of the flexible circuit board 1; a plurality of the first substrate pads 11 are equally spaced along the length of the flexible circuit board 1. The aforementioned flexible circuit board 1 is a strip-shaped flexible circuit board; a cover plate 6 is bonded to the body on the side opposite to the flexible circuit board 1; the aforementioned cover plate 6 is a glass cover plate.

[0020] When using the fingerprint side button in the aforementioned electronic device, while achieving fingerprint recognition and physical pressure control, the flexible circuit board has several first substrate pads in the central area facing the fingerprint recognition chip. At least one second substrate pad is provided on each side of the first substrate pads and at each end of the flexible circuit board. The fingerprint recognition chip has several first chip pads corresponding to the first substrate pads and several second chip pads corresponding to the second substrate pads on the side facing the flexible circuit board. The area of ​​the first chip pad is larger than the area of ​​the first substrate pad directly below it. The second chip pads have the same area as the second substrate pads. A gap layer is formed between the flexible circuit board and the chip, and adjacent first substrate pads and adjacent first substrate pads... A connecting gap channel is formed between the pad and the second substrate pad. An adhesive layer filled in the gap channel covers the outside of the solder joint between the first chip pad and the first substrate pad. By setting the pad size differently, the chip position can be avoided from shifting and affecting the soldering accuracy during the heating and cooling process. It can also prevent the flux in the solder paste from overflowing when it melts at high temperature and then solidifying when it cools down and blocking the adhesive channel. Through a simple single-sided adhesive injection process, the gap layer and gap channel can be fully filled, which can improve the overall structural strength and waterproof and dustproof performance of the fingerprint side key. It can also prevent the pad and solder joint from being corroded by chemical solutions in subsequent reliability testing and other processes, thus improving the overall weather resistance and reliability of the fingerprint side key.

[0021] The above embodiments are only for illustrating the technical concept and features of the present invention, and are intended to enable those skilled in the art to understand the content of the present invention and implement it accordingly. They should not be construed as limiting the scope of protection of the present invention. All equivalent changes or modifications made in accordance with the spirit and essence of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A fingerprint side button for an electronic device, comprising: A flexible circuit board (1) and a body containing a fingerprint recognition chip (2), wherein one side surface of the flexible circuit board (1) is electrically connected to the fingerprint recognition chip (2) on the body (2), characterized in that: a plurality of first substrate pads (11) are provided in the middle region of the flexible circuit board (1) facing the fingerprint recognition chip (2), and at least one second substrate pad (12) is provided on both sides of the first substrate pads (11) and at both ends of the flexible circuit board (1), and a plurality of first chip pads (21) corresponding to the first substrate pads (11) and second chip pads (22) corresponding to the second substrate pads (12) are provided on the side of the fingerprint recognition chip (2) facing the flexible circuit board (1). The area of ​​the first chip pad (21) is larger than the area of ​​the first substrate pad (11) located directly below it. The second chip pad (22) and the second substrate pad (12) have the same area. Each first chip pad (21) is connected to the corresponding first substrate pad (11), and each second substrate pad (12) is connected to the corresponding second chip pad (22) by solder paste. This forms a gap layer (3) between the flexible circuit substrate (1) and the chip (2), and a connecting gap channel (31) is formed between adjacent first substrate pads (11) and between adjacent first substrate pads (11) and second substrate pads (12). An adhesive layer (4) filled in the gap channel (31) covers the outside of the solder joint between the first chip pad (21) and the first substrate pad (11).

2. The fingerprint side button for electronic devices according to claim 1, characterized in that: The first substrate pad (11), the second substrate pad (12), the first chip pad (21), and the second chip pad (22) are all rectangular pads.

3. The fingerprint side button for electronic devices according to claim 2, characterized in that: The length of each of the first chip pads (21) is greater than the length of the first substrate pad (11) located directly below it.

4. The fingerprint side button for electronic devices according to claim 1, characterized in that: The adhesive layer (4) is an epoxy adhesive layer.

5. The fingerprint side button for electronic devices according to claim 1, characterized in that: The two opposite side surfaces of the adhesive layer (4) are flush with the side surfaces of the flexible circuit board (1).

6. The fingerprint side button for an electronic device according to claim 1, characterized in that: Several first substrate pads (11) are arranged at equal intervals along the length of the flexible circuit substrate (1).

7. The fingerprint side button for an electronic device according to claim 1, characterized in that: Several first substrate pads (11) are arranged in two rows, and multiple first substrate pads (11) in each row are equally spaced along the length direction of the flexible circuit substrate (1).

8. The fingerprint side button for an electronic device according to claim 1, characterized in that: The flexible circuit board (1) has several grooves (13) on its surface facing the fingerprint recognition chip (2), and the surface of the first substrate pad (11) embedded in the groove (13) is lower than the surface of the flexible circuit board (1).

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