TW201805791A - Capacitive fingerprint sensing module improves the accuracy of sensed result - Google Patents

Abstract

The capacitive fingerprint sensing module comprises a flexible printed circuit board, a lower conductive adhesive layer, an upper conductive adhesive layer, and a positioning frame. The flexible circuit board comprises an upper surface and a lower surface. The upper surface is provided with a finger pressing area and a first sensing area. The lower surface is provided with a second sensing area. The lower conductive adhesive layer is coated on the second sensing area, and covers the second sensing electrodes. The upper conductive adhesive layer is coated on the finger- pressing area. The positioning frame is provided with an insertion slot and an upward opening connected with the insertion slot. The flexible printed circuit board penetrates through the insertion slot to be embedded and fixed in the positioning frame, and the finger pressing area is located at the position corresponding to the opening and is exposed out of the opening; so that the accuracy of the sensed result of capacitive fingerprint sensing module can be improved.

Description

Capacitive fingerprint sensor module

This creation is about a capacitive sensor module, especially a capacitive fingerprint sensor module with a conductive adhesive package structure.

In response to the needs of users and the development of technology, capacitive touch technology has been widely used in electronic products. Taking capacitive touch technology for fingerprint identification as an example, fingerprint information is collected through miniaturized and thin capacitive sensors, and the characteristic points of the fingerprint are compared to identify the true identity of the user. False. Therefore, the technology of capacitive fingerprint recognition has been gradually applied to increase the security of user data, such as the fields of flash drives, laptops, mobile phones, credit cards, passports, ID cards, etc.

Since the accuracy of the fingerprint feature points collected by the capacitive sensor is related to the quality of the user's identity, the conductivity is increased to increase the accuracy of the sensed capacitance value. This is a breakthrough for professionals in this field. Technical key.

One of the objectives of this creation is to provide a capacitive fingerprint sensor module with good conductivity to improve the accuracy of the capacitance value sensed.

In order to achieve the purpose of previous disclosure, the capacitive fingerprint sensor module proposed in this creation includes a flexible circuit board, a lower conductive adhesive layer, an upper conductive adhesive layer, and a positioning frame. The flexible circuit board includes an upper surface and a lower surface. The upper surface has a finger pressing area and a first sensing area corresponding to the finger pressing area, wherein a plurality of first sensing electrodes are arranged on the first sensing area. The lower surface has a second sensing area corresponding to a finger pressing area, wherein a plurality of second sensing electrodes are arranged on the second sensing area. The lower conductive adhesive layer is coated on the second sensing area of the flexible circuit board and covers the second sensing electrodes. The upper conductive adhesive layer is coated on the finger pressing area. The positioning frame is formed with a slot and an upward opening. The slot is formed on a side wall of the positioning frame and communicates with the opening. The flexible circuit board passes through the slot to be embedded and fixed in the positioning frame, and the finger pressing area of the upper surface of the flexible circuit board is located at a position corresponding to the opening and exposed from the opening.

This creation uses the lower conductive adhesive layer used in the capacitive fingerprint sensing module to increase the conductivity of the sensing electrodes to improve the accuracy of the sensing results of the capacitive fingerprint sensing module.

In order to better understand the techniques, methods and effects adopted by this creation to achieve the intended purpose, please refer to the following detailed descriptions and drawings of this creation. I believe that the purpose, characteristics and features of this creation can be in-depth and Specific understanding, however, the drawings are provided for reference and explanation only, and are not intended to limit the creation.

The technical content and detailed description of this creation are described below in conjunction with the drawings.

Please refer to FIG. 1 and FIG. 2. The original capacitive fingerprint sensor module includes a flexible circuit board 41, a lower conductive adhesive layer 62, and a positioning frame 51.

In this creation, the flexible circuit board 41 is a double-side FPCB, which includes an upper surface 411 and a lower surface 412. The upper surface 411 has a finger pressing area 41R, wherein the finger pressing area 41R is an effective area of a user's finger. Please refer to FIG. 3A, the capacitive fingerprint sensor module further includes a control unit 71. Taking this embodiment as an example, the control unit 71 is disposed on the lower surface 412 of the flexible circuit board 41. However, the control unit 71 may also be disposed on the upper surface 411 of the flexible circuit board 41 without being limited to being disposed on the lower surface 412.

In addition, please refer to FIG. 3B. The upper surface 411 has a first sensing region 421R corresponding to the finger pressing region 41R of the upper surface 411, and the positional relationship between the finger pressing region 41R and the first sensing region 421R is in phase. Corresponding two areas. Please refer to FIG. 3C. The lower surface 412 has a second sensing region 422R corresponding to the finger pressing region 41R of the upper surface 411, and the positional relationship between the finger pressing region 41R and the second sensing region 422R is corresponding. Two areas. A plurality of first sensing electrodes 701 are laid out on the first sensing region 421R, and the first sensing electrodes 701 are arranged on the first sensing region of the upper surface 411 in a row manner. On 421R, the first sensing electrodes 701 may be row electrodes. The first sensing electrodes 701 are electrically connected to a first bus bar 711, wherein the first bus bar 711 receives a value of a sensing capacitance generated by the first sensing electrodes 701, which will be described later. A plurality of second sensing electrodes 702 are arranged on the second sensing region 422R, and the second sensing electrodes 702 are arranged on the second sensing region 422R of the lower surface 412 in a row manner. The second sensing electrodes 702 may be column electrodes. The second sensing electrodes 702 are electrically connected to a second bus bar 712, wherein the second bus bar 712 receives a value of an induced capacitance generated by the second sensing electrodes 702, which will be described later. However, the above-mentioned first sensing electrodes 701 and the second sensing electrodes 702 are not limited to a multi-row column structure and a multi-row row structure, respectively. The architectures are interchangeable, that is, the first sensing electrodes 701 are a multi-row row structure, and the second sensing electrodes 702 are a multi-row row structure. In addition, the lower conductive adhesive layer 62 is formed on the second sensing region 422R of the lower surface 412 of the flexible circuit board 41, and the lower conductive adhesive layer 62 covers the second sensing electrodes 702. The lower conductive adhesive layer 62 may be an anisotropic conductive adhesive layer, but the conductive material is not limited.

As shown in FIG. 1 and FIG. 2, the positioning frame 51 is formed with a slot 53 and an upward opening 52. The slot 53 is formed on a side wall of the positioning frame 51 and communicates with the opening 52.

The flexible circuit board 41 passes through the slot 53 to be embedded and fixed in the positioning frame 51, and the finger pressing area 41R is exposed through the opening 52 of the positioning frame 51. One side of the flexible circuit board 41 abuts against the other side wall of the positioning frame 51 far from the slot 53, so that the finger pressing area 41R of the upper surface 411 and the second sensing of the lower surface 412 The region 422R is located at a position corresponding to the opening 52, and the finger pressing region 41R is exposed from the opening 52.

The lower conductive adhesive layer 62 is applied between the bottom surface of the opening 52 of the positioning frame 51 and the second sensing area 422R of the flexible circuit board 41 to adhere and fix the flexible circuit board 41 in the positioning frame 51. After the lower conductive adhesive layer 62 is hardened, in addition to improving the conductivity, it also has the effect of supporting the flexible circuit board 41.

As shown in FIG. 3B and FIG. 3C, the control unit 71 is electrically connected to the first sensing electrodes 701 and the second sensing electrodes 702 through the wires arranged on the flexible circuit board 41. Each of the second sensing electrodes 702 receives a touch-pressure sensing signal to generate a sensing capacitance value correspondingly. For example, when a user's finger touches the staggered positions of the first sensing electrodes 701 and the second sensing electrodes 702, it is regarded as receiving the pressure sensing signal. The electrode 701 and the second sensing electrodes 702 will generate the sensing capacitance value correspondingly.

The control unit 71 receives the sensing capacitance values through the first bus 711 and the second bus 712, and determines whether the first sensing electrodes 701 and the second sensing electrodes 702 are detected by the sensing capacitance values. Touch. When the user's finger is pressed against the finger pressing area 41R of the upper surface 411, or when the user presses the finger pressing area 41R at a different position, the first sensing electrodes 701 and the second sensing electrodes are caused. The magnitude of each of the touch-pressure sensing signals received at 702 is different, and therefore the magnitude of each of the sensing capacitance values corresponding to each other is also different. Therefore, the control unit 71 determines whether the first sensing electrodes 701 and the second sensing electrodes 702 are touched according to the sensing capacitance values, and can also determine the position and range of the user's finger touch. .

The capacitive fingerprint sensor module further includes an integrated circuit 72. The integrated circuit 72 is disposed on the lower surface 412 of the flexible circuit board 41. However, the integrated circuit 72 may also be disposed on the upper surface 411 of the flexible circuit board 41 without being limited to being disposed on the lower surface 412. The integrated circuit 72 is electrically connected to the control unit 71 through a wire disposed on the flexible circuit board 41. The integrated circuit 72 receives information obtained by the control unit 71 that a user's finger presses on the first sensing electrodes 701 and the second sensing electrodes 702. Taking the integrated circuit 72 as a fingerprint-sensing integrated circuit as an example, the fingerprint-sensing integrated circuit analyzes the fingerprint information according to the touch-sensitive fingerprint information to identify the authenticity of the user's identity.

As shown in FIG. 4, the first embodiment of the capacitive fingerprint sensor module is created. The capacitive fingerprint sensor module includes the aforementioned structural features. In conjunction with FIG. 3A, the lower surface of the capacitive fingerprint sensor module is shown. The lower conductive adhesive layer 62 is coated on the second sensing region 422R of 412 to cover the second sensing electrodes 702. By coating the lower conductive adhesive layer 62 on the second sensing area 422R of the flexible circuit board 41, in addition to increasing the conductivity of the second sensing electrodes 702 and improving the sensing result of the capacitive fingerprint sensing module In addition to accuracy, it also has the effect of supporting the flexible circuit board 41.

In addition, the flexible circuit board 41 further forms an upper conductive adhesive layer 61. The upper conductive adhesive layer 61 is coated on the finger pressing area 41R and the first sensing area 421R of the upper surface 411 and is located in the opening 52 of the positioning frame 51. In this embodiment, the top surface of the upper conductive adhesive layer 61 and the top surface of the positioning frame 51 are located on the same plane. The upper conductive adhesive layer 61 is coated on the finger pressing area 41R of the upper surface 411 of the flexible circuit board 41, and the lower conductive surface 41R of the lower surface 412 of the flexible circuit board 41 is coated with the lower Conductive adhesive layer 62. The upper conductive adhesive layer 61 may be a hard conductive adhesive layer or a soft conductive adhesive layer. Furthermore, the upper conductive adhesive layer 61 may be an anisotropic conductive adhesive layer, however, the conductive material is not limited. In this way, by coating the upper conductive adhesive layer 61 and the lower conductive adhesive layer 62 at the same time, the conductivity of the first sensing electrodes 701 and the second sensing electrodes 702 is increased, and the sensing of the capacitive fingerprint sensing module is improved. The accuracy of the results. Furthermore, after the upper conductive adhesive layer 61 is hardened, it also has a scratch-resistant application.

As shown in FIG. 5, a second embodiment of the capacitive fingerprint sensing module of the present invention is created. The difference between this embodiment and the first embodiment shown in FIG. 4 lies in the soft circuit of the second embodiment shown in FIG. 5. The plate 41 further includes a scratch-resistant layer 63, wherein the scratch-resistant layer 63 is disposed on the upper conductive adhesive layer 61. In this embodiment, the top surface of the scratch-resistant layer 63 and the top surface of the positioning frame 51 are located on the same plane. When the user directly presses the finger against the scratch-resistant layer 63, not only can the finger press the finger pressing area 41R of the upper surface 411, but also the upper conductive adhesive layer 61 can be protected by the scratch-resistant layer 63. In order to avoid the user's fingers or other objects from directly scratching the upper conductive adhesive layer 61, thereby increasing the service life of the upper conductive adhesive layer 61 and maintaining the conductive effect.

This creation can be set on pen drives, laptops, mobile phones, credit cards, passports, ID cards for fingerprint identification. In summary, this creation has the following characteristics and advantages:

1. By using the lower conductive adhesive layer and the upper conductive adhesive layer used in the capacitive fingerprint sensing module, the conductivity of the first sensing electrodes and the second sensing electrodes is increased to improve the capacitive fingerprint The accuracy of the sensing module's sensing results.

2. The anti-scratch layer used by the capacitive fingerprint sensor module protects the upper conductive adhesive layer to prevent the user's fingers or other objects from directly scratching the upper conductive adhesive layer, thereby increasing the use of the upper conductive adhesive layer. Life and maintain conductive effect.

41‧‧‧flexible circuit board
411‧‧‧upper surface
412‧‧‧ lower surface
41R‧‧‧Finger press area
421R‧‧‧The first sensing area
422R‧‧‧Second sensing area
51‧‧‧ positioning frame
52‧‧‧ opening
53‧‧‧slot
61‧‧‧on conductive adhesive layer
62‧‧‧ lower conductive adhesive layer
63‧‧‧Anti-scratch layer
701‧‧‧first sensing electrode
702‧‧‧Second sensing electrode
711‧‧‧First bus
712‧‧‧Second bus
71‧‧‧control unit
72‧‧‧Integrated Circuit

Figure 1: Top view of the three-dimensional appearance of the capacitive fingerprint sensor module. Figure 2: A three-dimensional exploded bottom view of the capacitive fingerprint sensor module. FIG. 3A is a schematic side plan view of a flexible circuit board of the capacitive fingerprint sensor module. FIG. 3B is a schematic top plan view of a flexible circuit board of the capacitive fingerprint sensor module. FIG. 3C is a schematic bottom plan view of a flexible circuit board of the capacitive fingerprint sensor module of the present invention. FIG. 4 is a schematic cross-sectional view of the first embodiment of the capacitive fingerprint sensor module. FIG. 5 is a schematic cross-sectional view of a second embodiment of the capacitive fingerprint sensor module.

41‧‧‧flexible circuit board

412‧‧‧ lower surface

51‧‧‧ positioning frame

52‧‧‧ opening

53‧‧‧slot

62‧‧‧ lower conductive adhesive layer

702‧‧‧Second sensing electrode

712‧‧‧Second bus

71‧‧‧control unit

72‧‧‧Integrated Circuit

Claims (8)

A capacitive fingerprint sensor module includes: a flexible circuit board including: an upper surface having a finger pressing area and a first sensing area corresponding to the finger pressing area, wherein a plurality of first are arranged on the first sensing area A sensing electrode; and a lower surface having a second sensing area corresponding to a finger pressing area, wherein a plurality of second sensing electrodes are arranged on the second sensing area; a lower conductive adhesive layer is coated on the first surface of the flexible circuit board; Two sensing areas and covering the second sensing electrodes; a conductive adhesive layer coated on the finger pressing area; and a positioning frame forming a slot and an upward opening, wherein the plug A groove is formed on a side wall of the positioning frame and communicates with the opening; wherein the flexible circuit board passes through the slot to be embedded and fixed in the positioning frame, and the finger of the upper surface of the flexible circuit board is pressed by the finger The area is located at a position corresponding to the opening and is exposed from the opening. The capacitive fingerprint sensor module according to claim 1, wherein the top surface of the upper conductive adhesive layer and the top surface of the positioning frame are located on the same plane. The capacitive fingerprint sensor module according to claim 2, wherein the flexible circuit board further comprises: a scratch-resistant layer disposed on the upper conductive adhesive layer. The capacitive fingerprint sensor module according to claim 3, wherein the top surface of the scratch-resistant layer and the top surface of the positioning frame are located on the same plane. The capacitive fingerprint sensing module according to claim 1 or 2, wherein the lower conductive adhesive layer and the upper conductive adhesive layer are a hard conductive adhesive layer or a soft conductive adhesive layer. The capacitive fingerprint sensing module according to claim 5, wherein the lower conductive adhesive layer and the upper conductive adhesive layer are an anisotropic conductive adhesive layer. The capacitive fingerprint sensing module according to claim 1, further comprising: a control unit, which is disposed on the lower surface of the flexible circuit board, and electrically connects the first sensing electrodes and the first sensing electrodes through a plurality of wires. Two sensing electrodes; wherein each of the first sensing electrodes and each of the second sensing electrodes receive a touch pressure sensing signal to generate a sensing capacitance value correspondingly; the control unit receives the sensing capacitance values, and according to the sensing The capacitance value determines whether the first sensing electrodes and the second sensing electrodes are pressed. The capacitive fingerprint sensing module according to claim 1, further comprising: a control unit, which is disposed on the upper surface of the flexible circuit board and electrically connects the first sensing electrodes and the first sensing electrodes through a plurality of wires. Two sensing electrodes; wherein each of the first sensing electrodes and each of the second sensing electrodes receive a touch pressure sensing signal to generate a sensing capacitance value correspondingly; the control unit receives the sensing capacitance values, and according to the sensing The capacitance value determines whether the first sensing electrodes and the second sensing electrodes are pressed.