TW201828006A - Acoustic fingerprint recognition device, manufacturing method thereof and electronic device using same - Google Patents

Abstract

The sonic fingerprint identification device includes a circuit substrate, a supersonic sensing unit formed on the surface of the circuit substrate, and a flexible circuit board, the circuit substrate includes a circuit, the flexible circuit board is formed with a connection pad, and the supersonic sensing unit includes A first electrode, a piezoelectric polymer layer, and a second electrode disposed on a surface of the circuit substrate and electrically connected to the circuit, the flexible circuit board are electrically connected to the circuit and the second electrode through connection pads, respectively To realize signal transmission, the connection pad electrically connected to the circuit board is located on the surface of the circuit board, and the connection pad electrically connected to the second electrode is stacked with the second electrode. The invention also provides a preparation method of the sonic fingerprint identification device, and an electronic device using the sonic fingerprint identification device.

Description

Sonic fingerprint identification device, manufacturing method thereof, and electronic device using the same

The invention relates to a sonic fingerprint identification device, a manufacturing method thereof, and an electronic device using the sonic fingerprint identification device.

As portable electronic devices are widely used, users have put forward more functional requirements for portable electronic devices. The fingerprint recognition device is installed in the portable electronic device due to its privacy protection function to increase the user experience. Fingerprint recognition devices can be divided into optical, capacitive, sonic, etc. The sonic fingerprint identification device is widely used because its operation is not easily affected by the ambient temperature and humidity, and has a long life and high resolution.

The ultrasonic fingerprint identification element can identify the finger fingerprint placed on the fingerprint identification element. When the user places his finger on the surface of the fingerprint identification element, the fingerprint of the user's finger will be recognized, and then the identity of the user is verified.

The supersonic sensing unit of the receiving / transmitting integrated sonic fingerprint identification device is arranged on the circuit substrate. The supersonic sensing unit has a silver electrode on the side away from the circuit substrate. The silver electrode surface is pasted with a protective reinforcement layer, the silver electrode and the circuit The substrate is electrically connected to the control device through a flexible circuit board to provide driving electrical signals. In the traditional structure, because the surface of the silver electrode is pasted with a protective reinforcement layer, the silver electrode is provided to extend from below the protective reinforcement layer to the circuit substrate to be electrically connected to one end of the flexible circuit board, and the flexible circuit board is connected to the silver electrode At the same time, one end is electrically connected to the circuit board by a golden finger, and the other end of the flexible circuit board is connected to the control device. During the layout of the flexible circuit board, due to the limited size of the circuit board, the gold fingers used to electrically connect the circuit board on the flexible circuit board partially extend from the edge of the circuit board in a suspended state, from the edge of the circuit board The extended gold finger part is easy to break and damage, causing the sonic fingerprint identification device to malfunction. How to avoid the occurrence of the above-mentioned failure is a problem urgently needed to be solved by those skilled in the art.

In view of this, the present invention provides an sonic fingerprint recognition device, which effectively solves the problem that the flexible circuit board extends from the edge of the circuit substrate in a suspended state, and the gold finger portion extending from the edge of the circuit substrate is easily broken and damaged The problem of the sound wave fingerprint identification device malfunctioning.

In addition, a manufacturing method of the sonic fingerprint identification device and an electronic device using the sonic fingerprint identification device are also provided.

An sonic fingerprint identification device includes a circuit substrate, a supersonic sensing unit formed on the surface of the circuit substrate, and a flexible circuit board, the circuit substrate includes a circuit, the flexible circuit board is formed with a connection pad, and the supersonic sensing unit It includes a first electrode, a piezoelectric polymer layer and a second electrode disposed on a surface of the circuit board and electrically connected to the circuit. The flexible circuit board is electrically connected to the circuit and the second electrode through connection pads, respectively In order to realize signal transmission, the connection pad electrically connected to the circuit board is located on the surface of the circuit board, and the connection pad electrically connected to the second electrode is stacked with the second electrode.

A method for preparing a sonic fingerprint identification device includes the following steps:

A circuit substrate is provided, the circuit substrate contains a circuit and the surface of the circuit substrate contains a first electrode electrically connected to the circuit, and a piezoelectric polymer layer is coated on the surface of the first electrode;

The piezoelectric polymer layer is dried and crystallized and polarized;

A second electrode layer is coated on the surface of the piezoelectric polymer layer by one process;

Providing a flexible circuit board with connection pads to electrically connect the flexible circuit board to the second electrode;

Electrically connecting the flexible circuit board and the circuit of the circuit substrate;

The connection pad on the flexible circuit board is firmly combined with the circuit substrate and the second electrode by a single pressing process.

An electronic device includes a body and the sonic fingerprint identification device disposed in the body.

In the sonic fingerprint identification device of the present invention, the area where the flexible circuit board is electrically connected to the two electrodes is changed, and the area where the flexible circuit board is electrically connected to one of the electrodes is not located on the surface of the circuit board, and this area overlaps the ultrasonic sensing unit . Correspondingly, the routing method of the flexible circuit board has also changed, and the golden fingers in the flexible circuit board are no longer located at the above edge positions. Therefore, the breaking of the golden finger is effectively avoided, and the probability of failure of the sonic fingerprint identification device is reduced.

At the same time, the structure of the sonic fingerprint identification device has changed, and the corresponding manufacturing method has changed. In the traditional structure, one electrode of the ultrasonic sensing unit is a silver paste material, which is manufactured by coating. The silver paste electrode needs to be coated on the surface of the piezoelectric layer in the ultrasonic sensing unit first, and then by another One coating process extends the electrode to the surface of the circuit board; during the pressing process of the electrical connection area of the flexible circuit board and the electrode, the electrical connection area of the flexible circuit board and the two electrodes is in different levels, so it needs to be performed twice Suppression process. In this case, since the electrical connection area corresponding to the silver paste electrode overlaps with the ultrasonic sensing unit, only the silver paste needs to be coated on the surface of the piezoelectric layer in the ultrasonic sensing unit, which reduces a process compared with the traditional structure ; And, in this case, the electrical connection area of the flexible circuit board and the two electrodes are in the same level direction, so the above-mentioned pressing can be completed by one process. In addition, in the traditional structure, a flexible circuit board that extends beyond the sonic fingerprint recognition device and contains gold fingers needs to be coated with a protective layer; and in this case, the flexible circuit boards containing gold fingers are located on the Inside the structure, there is no need to apply a protective layer.

In summary, compared with the traditional structure, the sonic fingerprint identification device in this case can effectively avoid the breakage of gold fingers, reduce the probability of failure of the sonic fingerprint identification device, and can also simplify the manufacturing process and save costs.

In order to make the technical content disclosed in this application more detailed and complete, reference may be made to the drawings and the following various specific embodiments of the present invention. The same symbols in the drawings represent the same or similar components. However, those of ordinary skill in the art should understand that the embodiments provided below are not intended to limit the scope of the present invention. In addition, the drawings are for illustrative purposes only, and are not drawn according to their original dimensions.

The specific embodiments of the present invention will be further described in detail below with reference to the drawings.

First embodiment

Please refer to FIGS. 1 and 2 at the same time. The sonic fingerprint identification device 100 according to the first embodiment of the present invention includes a supersonic sensing unit 110, a signal transmission unit 120, a circuit substrate 130, a cover 140, a protection unit 150, and a control unit 160.

The circuit substrate 130 is fixed on one side of the cover plate 140, the ultrasonic sensing unit 110 is disposed on the side of the circuit substrate 130 away from the cover plate 140, the signal transmission unit 120 and the control unit 160, the ultrasonic sensing unit 110 and the circuit substrate 130 respectively Electrically connected to realize signal transmission between the control unit 160, the ultrasonic sensing unit 110 and the circuit substrate 130.

The cover plate 140 includes a cover glass 142 and a cover adhesive layer 141. The cover glass 142 is combined with the circuit substrate 130 through the cover adhesive layer 141. The surface of the cover glass 142 facing the cover adhesive layer 141 can be coated with an ink layer to shield or decorate. In other embodiments, the cover glass 142 can also be replaced by a transparent plastic cover.

The ultrasonic sensing unit 110 includes a piezoelectric polymer layer 113, a conductive adhesive layer 114, a first electrode 111, and a second electrode 112. The first electrode 111 is formed on the surface of the circuit substrate 130 away from the cover plate 140; the piezoelectric polymer layer 113 is formed on the surface of the first electrode 111 and covers the first electrode 111; the second electrode 112 is provided on the surface of the piezoelectric polymer layer 113 ; The conductive adhesive layer 114 is formed on the surface of the second electrode 112 and covers the second electrode 112. The material of the first electrode 111 may be indium tin oxide (ITO). The conductive adhesive layer 114 is a conductive adhesive. The material of the second electrode 112 may be silver paste.

The circuit substrate 130 includes a first surface 131 and a second surface 132 opposite to the first surface 131. The first surface 131 is in contact with the cover adhesive layer 141. The circuit substrate 130 contains circuits (not shown), which can be used to receive, process, and transmit the coupled electrical signals generated when the ultrasonic sensing unit 110 receives ultrasonic waves. The first electrode 111 is electrically connected to the circuit. The sonic fingerprint identification device 100 defines an active identification area (AA area). The projection area of the effective identification area on the cover plate 140 is an area where the sonic fingerprint identification device 100 can effectively identify fingerprints. The first electrode 111 Corresponding to the effective identification area setting. In this embodiment, the circuit substrate 130 is a thin film transistor (TFT) array substrate. The TFT array substrate includes an array of pixel circuits. Each pixel circuit may include one or more TFTs. Each TFT includes at least one pixel. An electrode, a plurality of pixel electrodes are combined to form the first electrode 111. Please refer to FIG. 3 further. The circuit substrate 130 further includes a third metal connection pad 1321 for electrically connecting the signal transmission unit 120. The third metal connection pad 1321 is electrically connected to the circuit, and is disposed on the area where the second surface 132 of the circuit substrate 130 is not covered by the conductive adhesive layer 114. In other embodiments, the circuit substrate 130 may also be a printed circuit board, a flexible circuit board, or a circuit board having a conductive structure that can serve as the first electrode 111.

Please further refer to FIG. 4. The signal transmission unit 120 includes a flexible circuit board 123, a first metal connection pad 121, and a second metal connection pad 122. The first metal connection pad 121 and the second metal connection pad 122 are formed on the flexible circuit board 123 and electrically connected thereto. The first metal connection pad 121 is adhered to the second electrode 112 through the conductive adhesive layer 114 and is electrically connected to the second electrode 112. The flexible circuit board 123 is electrically connected to the third metal connection pad 1321 of the circuit substrate 130 through the second metal connection pad 122.

The flexible circuit board 123 includes four different areas, namely a first area 1231, a second area 1232, a third area 1233, and a fourth area 1234. The first area 1231 is a complete continuous structure that overlaps the effective identification area and is slightly larger than the effective identification area. The first metal connection pad 121 is located on the side of the first area 1231 near the conductive adhesive layer 114. The flexible circuit board 123 covers the conductive adhesive layer 114. The conductive adhesive layer 114 is disposed along the surface of the first area 1231. The conductive adhesive layer 114 covers the second electrode 112 and is effectively identified with the The areas overlap. In the overlapping direction, the area of the conductive adhesive layer 114 is greater than the area of the effective identification area, and the distance between the edge of the conductive adhesive layer 114 and the edge of the effective identification area is greater than 50 μm. One end of the second area 1232 is adjacent to the first area 1231, and the other end is connected to the control unit 160. The third region 1233 is connected to the first region 1231 on one side and to the fourth region 1234 on the other side. In this embodiment, the third area 1233 is attached to a side of the third metal connection pad 1321 of the ultrasonic sensing unit 110 facing the circuit substrate 130. The fourth area 1234 is located on the portion of the second surface 132 of the circuit substrate 130 that is not covered by the piezoelectric polymer layer 113. The second metal connection pad 122 is located on the side of the fourth area 1234 near the second surface 132.

The protection unit 150 is formed on a side of the ultrasonic sensing unit 110 away from the circuit substrate 130. The protective unit 150 includes a protective layer 151 and a protective adhesive layer 153. The protective layer 151 is adhered to the surface of the flexible circuit board 123 away from the circuit substrate 130 by the protective adhesive layer 153 and is disposed corresponding to the ultrasonic sensing unit 110.

A working cycle of the sonic fingerprint identification device 100 includes two parts: a transmitting stage and a receiving stage. In the emission phase, the control unit 160 gives different voltage signals to the first electrode 111 and the second electrode 112 at the same time by the flexible circuit board 123, so that a potential difference is formed between the two sides of the piezoelectric polymer layer 113, thereby generating mechanical vibration to emit ultrasonic waves. In the receiving stage, the flexible circuit board 123 only provides an operating voltage to the first electrode 111 and the second electrode 112 so that the two electrodes jointly maintain the normal operation of the piezoelectric polymer layer 113. At this stage, the first electrode 111 also has the function of electrical coupling. That is, in the receiving stage, the piezoelectric polymer layer 113 receives reflected ultrasonic waves and generates induced charges. The first electrode 111 couples the induced charges of the piezoelectric polymer layer 113 to the circuit substrate 130, and the circuit substrate 130 collects the coupling current And analysis, and then transmitted to the control device through the flexible circuit board 123.

In the sonic fingerprint identification device 100 described above, the area where the flexible circuit board 123 and the second electrode 112 are electrically connected is not located on the surface of the circuit board 130 but located in the effective identification area. Correspondingly, the layout method of the flexible circuit board 123 also changes, and the second metal connection pad 122 electrically connected to the flexible circuit board 123 and the circuit substrate 130 no longer exceeds the edge position of the circuit substrate 130. Therefore, the breakage of the second metal connection pad 122 is effectively avoided, and the probability of failure of the sonic fingerprint identification device 100 is reduced.

Second embodiment

Please refer to FIGS. 5 and 6 at the same time. The sonic fingerprint identification device 200 of the second embodiment of the present invention includes an electric supersonic sensing unit 210, a signal transmission unit 220, a circuit substrate 230, a cover 240, a protection unit 250 and a control unit 260 .

The circuit substrate 230 is fixed on one side of the cover plate 240. The ultrasonic sensing unit 210 and the signal transmission unit 220 are placed on the side of the circuit substrate 230 away from the cover plate 240. The signal transmission unit 220 and the control unit 260 and the ultrasonic sensing unit are respectively 210 and the circuit board 230 are electrically connected to realize signal transmission between the control unit 260, the ultrasonic sensing unit 210 and the circuit board 230.

The cover plate 240 includes a cover glass 242 and a cover adhesive layer 241. The cover glass 242 is combined with the circuit substrate 230 through the cover adhesive layer 241. The surface of the cover glass 242 facing the cover adhesive layer 141 can be coated with an ink layer to shield or decorate. In other embodiments, the cover glass 242 can also be replaced by a transparent plastic cover.

The ultrasonic sensing unit 210 includes a piezoelectric polymer layer 213, a conductive adhesive layer 214, a first electrode 211, and a second electrode 212. The first electrode 211 is formed on the surface of the circuit board 230 away from the cover plate 240; the piezoelectric polymer layer 213 is formed on the surface of the first electrode 211 and covers the first electrode 211; the second electrode 212 is disposed on the surface of the piezoelectric polymer layer 213 ; The conductive adhesive layer 214 is formed on the surface of the second electrode 212 and is disposed around the edge of the second electrode 212. The material of the first electrode 211 may be indium tin oxide (ITO). The conductive adhesive layer 214 is a conductive adhesive. The material of the second electrode 212 may be silver paste.

The circuit substrate 230 includes a first surface 231 and a second surface 232 opposite to the first surface 231. The first surface 231 is in contact with the cover plate adhesive layer 241. The circuit board 230 contains a circuit (not shown), which can be used to receive, process, and transmit the coupled electrical signals generated when the ultrasonic sensing unit 210 receives ultrasonic waves. The first electrode 211 is electrically connected to the circuit. The sonic fingerprint identification device 200 defines an active identification area (AA area). The projection area of the effective identification area on the cover plate 240 is an area where the sonic fingerprint identification device 200 can effectively identify fingerprints. The first electrode 211 Corresponding to the effective identification area setting. In this embodiment, the circuit substrate 230 is a thin film transistor (TFT) array substrate. The TFT array substrate includes an array of pixel circuits. Each pixel circuit may include one or more TFTs. Each TFT includes at least one pixel. An electrode, a plurality of pixel electrodes are combined to form the first electrode 211. Please refer to FIG. 7 further. The circuit substrate 230 further includes a third metal connection pad 2321 for electrically connecting the signal transmission unit 220. The third metal connection pad 2321 is electrically connected to the circuit, and is disposed on the area where the second surface 232 of the circuit substrate 230 is not covered by the second electrode 212. In other embodiments, the circuit substrate 230 may also be a printed circuit board, a flexible circuit board, or a circuit board having a conductive structure that can serve as the first electrode 211.

Please refer to FIG. 8 together. The signal transmission unit 220 includes a flexible circuit board 223, a first metal connection pad 221, and a second metal connection pad 222. The first metal connection pad 221 and the second metal connection pad 222 are formed on the flexible circuit board 223 and electrically connected thereto. The first metal connection pad 221 is bonded to the second electrode 212 through the conductive adhesive layer 214 and electrically connected to the second electrode 212. The flexible circuit board 223 is electrically connected to the third metal connection pad 2321 of the circuit substrate 230 through the second metal connection pad 222.

The flexible circuit board 223 has an opening 2230 corresponding to the effective identification area, so that the flexible circuit board 223 is disposed around the effective identification area. The conductive adhesive layer 214 is disposed corresponding to the area where the flexible circuit board 223 and the second electrode 212 overlap. In this example, the flexible circuit board 223 includes four different areas, namely a first area 2231, a second area 2232, a third area 2233, and a fourth area 2234. The first area 2231 is in the shape of a "mouth", and the opening 2230 is opened so that the first area 2231 is disposed around the effective identification area and partially overlaps the second electrode 212, and the first metal connection pad 221 is located The area 2231 is close to the side of the conductive adhesive layer 214. The flexible circuit board 223 covers the conductive adhesive layer 214. The conductive adhesive layer 214 is disposed along the surface of the first region 2231. The conductive adhesive layer 214 is disposed around the outer edge of the second electrode 212. The distance from the inner edge of the conductive adhesive layer 214 to the outer edge of the effective identification area is greater than 75 μm. One end of the second area 2232 is adjacent to the first area 2231, and the other end is connected to the control unit 260. The third region 2233 is connected to the first region 2231 on one side, and connected to the fourth region 2234 on the other side. In this embodiment, the third area 1233 is attached to a side of the third metal connection pad 1321 of the ultrasonic sensing unit 110 facing the circuit substrate 130. The fourth region 2234 is located on the portion of the second surface 232 of the circuit substrate 230 that is not covered by the piezoelectric polymer layer 213. The second metal connection pad 222 is located on the side of the fourth region 2234 near the second surface 232.

The protection unit 250 is formed on a side of the ultrasonic sensing unit 210 away from the circuit substrate 230. The protective unit 250 includes a protective layer 251 and a protective adhesive layer 253. The protective layer 251 is adhered to the surface of the flexible circuit board 223 away from the circuit substrate 230 by the protective adhesive layer 253, and is disposed corresponding to the ultrasonic sensing unit 210.

A working cycle of the sonic fingerprint identification device 200 includes two parts: a transmitting stage and a receiving stage. In the transmitting stage, the control unit 260 gives different voltage signals to the first electrode 211 and the second electrode 212 at the same time by the flexible circuit board 223, so that a potential difference is formed on both sides of the piezoelectric polymer layer 213, and then mechanical vibration is generated to emit ultrasonic waves. In the receiving stage, the flexible circuit board 223 only provides the first electrode 211 and the second electrode 212 with an operating voltage so that the two electrodes jointly maintain the normal operation of the piezoelectric polymer layer 213. At this stage, the first electrode 211 also has the function of electrical coupling. That is, in the receiving stage, the piezoelectric polymer layer 213 receives reflected ultrasonic waves and generates induced charges. The first electrode 211 couples the induced charges of the piezoelectric polymer layer 213 to the circuit substrate 230, and the circuit substrate 230 collects the coupling current And analysis, and then transmitted to the control device through the flexible circuit board 223.

In the sonic fingerprint identification device 200, the area where the flexible circuit board 223 and the second electrode 212 are electrically connected is not located on the surface of the circuit board 230, but is located in the effective identification area. Correspondingly, the layout method of the flexible circuit board 223 also changes, and the second metal connection pad 222 electrically connected between the flexible circuit board 223 and the circuit board 230 no longer exceeds the edge position of the circuit board 230. Therefore, the breakage of the second metal connection pad 122 is effectively avoided, and the probability of failure of the sonic fingerprint identification device 200 is reduced.

Example Three

As shown in FIG. 9, the preparation method of the sonic fingerprint identification device in this case includes the following steps:

Step S91, a circuit substrate is provided, the circuit substrate includes a circuit and a first electrode on the surface of the circuit substrate electrically connected to the circuit, and a piezoelectric polymer is coated on the surface area of the circuit substrate where the first electrode is formed Physical layer. In this embodiment, the circuit substrate is a TFT array substrate. The TFT array substrate includes an array of pixel circuits. Each pixel circuit includes one or more TFTs. Each TFT includes at least one pixel electrode. The pixel electrodes are combined to form the first electrode, and a piezoelectric polymer material is coated on the surface of the first electrode. The piezoelectric polymer material can be coated on the surface of the first electrode by spin coating, spray coating, dipping, dispensing or other feasible coating process.

In step S92, the piezoelectric polymer layer is dried and crystallized and polarized. The method for reducing the humidity may be baking, standing, ventilating or another drying process.

In step S93, a second electrode layer is coated on the surface of the piezoelectric polymer layer. The second electrode layer can be manufactured by one coating process. The method for reducing the humidity may be baking, standing, ventilating or another drying process. The coating material forming the second electrode is silver paste.

In step S94, a flexible circuit board is provided, the flexible circuit board includes a connection pad, the flexible circuit board is electrically connected to the second electrode, and the connection pad electrically connected to the second electrode and the second electrode are stacked. The connection pads on the flexible circuit board are metal connection pads. The metal connection pads include a first metal connection pad and a second metal connection pad. The flexible circuit board is bonded by a conductive adhesive layer between the first metal connection pad and the second electrode to achieve electrical connection.

Step S95, a protective layer is provided, and the protective layer is adhered to one side of the flexible circuit board. The area where the protective layer is bonded to the flexible circuit board overlaps with the first metal connection pad and completely covers the first metal connection pad.

In step S96, the flexible circuit board is electrically connected to the circuit of the circuit board, so that the connection pad electrically connected to the circuit board is located on the surface of the circuit board. The flexible circuit board is electrically connected to the circuit substrate through a second metal connection pad. The circuit substrate includes a third metal connection pad. The third metal connection pad and the second metal connection pad are electrically connected.

In step S97, the connection pad on the flexible circuit board is firmly combined with the circuit substrate and the second electrode by a pressing process.

In the traditional structure, one electrode of the ultrasonic sensing unit is a silver paste material, which is manufactured by coating. It needs to be coated on the surface of the piezoelectric layer in the ultrasonic sensing unit first, and then through another coating process The electrode is extended to the surface of the circuit substrate; during the pressing process of the electrical connection area between the flexible circuit board and the electrode, since the electrical connection area between the flexible circuit board and the two electrodes is in different levels, two pressing processes are required. In this case, since the electrical connection area corresponding to the silver paste electrode overlaps with the ultrasonic sensing unit, only the silver paste needs to be coated on the surface of the piezoelectric layer in the ultrasonic sensing unit, which reduces a process compared with the traditional structure ; And, in this case, the electrical connection area of the flexible circuit board and the two electrodes are in the same level direction, so the above-mentioned pressing can be completed by one process. In addition, in the traditional structure, a flexible circuit board that extends beyond the sonic fingerprint recognition device and contains gold fingers needs to be coated with a protective layer; and in this case, the flexible circuit boards containing gold fingers are located on the Inside the structure, there is no need to apply a protective layer.

10 and FIG. 11 together, the present invention also provides an electronic device 10 including a body 12 and an sonic fingerprint recognition device 900 disposed in the body 12. The sonic fingerprint recognition device 900 can be implemented as described above Any one of the sonic fingerprint identification devices described in Example 1 and Example 2. In FIG. 9, only the electronic device 10 is used as a mobile phone as an example. In other embodiments, the electronic device 10 may also be a personal computer, a smart home appliance, an industrial controller, or the like. When the electronic device 10 is a mobile phone, the sonic fingerprint identification device 900 can be set corresponding to the home button of the mobile phone, so that the home button has a function of touch operation.

In the foregoing, specific embodiments of the present invention have been described with reference to the accompanying drawings. However, those of ordinary skill in the art can understand that various changes and replacements can be made to the specific implementation of the present invention without departing from the spirit and scope of the present invention. These changes and replacements all fall within the scope defined by the claims of the present invention.

100, 200, 900 ‧‧‧sonic fingerprint recognition device

110, 210‧‧‧ Ultrasonic sensing unit

120, 220‧‧‧ signal transmission unit

130, 230‧‧‧ circuit board

140、240‧‧‧cover

150, 250‧‧‧Protection unit

160, 260‧‧‧ control unit

111、211‧‧‧First electrode

112、212‧‧‧Second electrode

113, 213‧‧‧ piezoelectric polymer layer

114, 214‧‧‧ conductive adhesive layer

121、221‧‧‧First metal connection pad

122, 222‧‧‧ Second metal connection pad

1321, 2321‧‧‧The third metal connection pad

123, 223‧‧‧ flexible circuit board

2230‧‧‧ opening

1231, 2231‧‧‧ First area

1232、2232‧‧‧Second area

1233, 2233 ‧‧‧ third area

1234, 2234‧‧‧ fourth area

131, 231‧‧‧ First surface

132, 232‧‧‧Second surface

142, 242‧‧‧ cover glass

141, 241‧‧‧ Cover adhesive layer

151, 251‧‧‧Protection layer

153, 253‧‧‧ protective adhesive layer

10‧‧‧Electronic device

12‧‧‧Body

FIG. 1 is a schematic top view of a sonic fingerprint identification device according to a first embodiment of the invention.

FIG. 2 is a cross-sectional view of FIG. 1 along II-II.

FIG. 3 is a schematic top view of the sonic fingerprint identification device of the first embodiment of the present invention after the flexible circuit board and the protective layer are removed.

4 is a schematic plan view of the signal transmission unit of the sonic fingerprint identification device according to the first embodiment of the invention.

FIG. 5 is a schematic top view of a sonic fingerprint identification device according to a second embodiment of the invention.

6 is a cross-sectional view of FIG. 5 along VI-VI.

7 is a schematic top view of the sonic fingerprint identification device of the second embodiment of the present invention after removing the flexible circuit board and the protective layer.

8 is a schematic plan view of a signal transmission unit of an sonic fingerprint identification device according to a second embodiment of the invention.

FIG. 9 is a schematic flow chart of the method for preparing the sonic fingerprint identification device of the present invention.

10 is a schematic diagram of an electronic device applying a preferred embodiment of the sonic fingerprint identification device of the present invention.

11 is a schematic cross-sectional view of FIG. 10 along XI-XI.

no

Claims (10)

A sonic fingerprint identification device includes a circuit board, a supersonic sensing unit formed on the surface of the circuit board, and a flexible circuit board. The circuit board includes a circuit, and a connection pad is formed on the flexible circuit board. The improvement lies in the The supersonic sensing unit includes a first electrode, a piezoelectric polymer layer, and a second electrode disposed on a surface of the circuit board and electrically connected to the circuit. The flexible circuit board is electrically connected to the circuit through a connection pad, respectively The second electrode is used for signal transmission. The connection pad electrically connected to the circuit board is located on the surface of the circuit board, and the connection pad electrically connected to the second electrode is stacked with the second electrode. The sonic fingerprint identification device according to claim 1, wherein the circuit substrate is a TFT array substrate, the TFT array substrate includes a pixel circuit array, and the circuit is the pixel circuit array; each pixel The circuit includes at least one TFT and has a pixel electrode electrically coupled to the pixel circuit, and a plurality of the pixel electrodes are combined to form the first electrode. The sonic fingerprint identification device according to claim 1, wherein the ultrasonic sensing unit further includes a conductive adhesive layer, and the connection pad electrically connected to the second electrode is bonded to the conductive adhesive layer by the conductive adhesive layer The second electrode is electrically connected to the second electrode. The sonic fingerprint identification device according to claim 3, wherein the sonic fingerprint identification device has an effective identification area, the flexible circuit board covers the conductive adhesive layer, and the conductive adhesive layer covers the first Two electrodes overlap with the effective identification area. The sonic fingerprint identification device according to claim 3, wherein the sonic fingerprint identification device has an effective identification area, the flexible circuit board has an opening corresponding to the effective identification area, and the conductive adhesive layer corresponds to the flexible circuit board The area overlapping the second electrode is provided. The sonic fingerprint identification device according to claim 1, wherein the piezoelectric polymer layer covers the first electrode, and the second electrode covers the piezoelectric polymer layer. An electronic device includes a body and a sonic fingerprint identification device disposed in the body, wherein the sonic fingerprint identification device is the sonic fingerprint identification device according to any one of the claims 1-6. A preparation method of an sonic fingerprint identification device includes the following steps: providing a circuit substrate including a circuit and a first electrode on the surface of the circuit substrate electrically connected to the circuit, and forming the circuit substrate on the circuit substrate A piezoelectric polymer layer is coated on the surface area of the first electrode; the piezoelectric polymer layer is dried and crystallized and polarized; and a second electrode layer is coated on the surface of the piezoelectric polymerized and crystallized layer Providing a flexible circuit board containing a connection pad, electrically connecting the flexible circuit board to the second electrode, so that the connection pad electrically connected to the second electrode and the second electrode are stacked; The flexible circuit board is electrically connected to the circuit of the circuit board, so that the connection pad electrically connected to the circuit board is located on the surface of the circuit board; the connection pad on the flexible circuit board is connected to the circuit board and the second electrode by a pressing process Firmly combined. The method for preparing a sonic fingerprint identification device according to claim 8, wherein the circuit substrate is a TFT array substrate, the TFT array substrate includes a pixel circuit array, and the circuit is the pixel circuit array; each A pixel circuit includes at least one TFT and has a pixel electrode electrically coupled to the pixel circuit, and a plurality of the pixel electrodes are combined to form the first electrode. The preparation method of the sonic fingerprint identification device according to claim 8, wherein the flexible circuit board and the second electrode are bonded by a conductive adhesive layer; the connection pads on the flexible circuit board are bonded by the conductive adhesive The adhesive layer is adhered to the second electrode and electrically connected to the second electrode.