CN118053183A - Ultrasonic fingerprint identification device and electronic equipment - Google Patents

Abstract

The invention discloses an ultrasonic fingerprint identification device and electronic equipment, wherein the ultrasonic fingerprint identification device comprises an ultrasonic fingerprint chip, a piezoelectric transducer and a connecting circuit, the piezoelectric transducer is arranged above the ultrasonic fingerprint chip, the piezoelectric transducer comprises a piezoelectric layer, an upper electrode positioned above the piezoelectric layer and a lower electrode positioned below the piezoelectric layer, the surface of the connecting circuit is provided with a first conducting sheet and a second conducting sheet, the first conducting sheet is electrically connected with the upper surface of the upper electrode, and the second conducting sheet is electrically connected with the ultrasonic fingerprint chip. The electronic equipment comprises a display screen and the ultrasonic fingerprint identification device, and the ultrasonic fingerprint identification device is arranged below the display screen. The invention effectively solves the problems of corner diffraction ripple and ESD pressure tolerance difference in the image; the ultrasonic fingerprint chip area can be reduced, which is beneficial to reducing the cost.

Description

Ultrasonic fingerprint identification device and electronic equipment

Technical Field

The invention relates to the technical field of fingerprint identification, in particular to an ultrasonic fingerprint identification device and electronic equipment.

Background

The structure of the conventional ultrasonic fingerprint sensor chip is shown in the plan view of fig. 1 and the cross-sectional view of fig. 2, and includes an ultrasonic fingerprint chip 1 and a piezoelectric transducer 2 disposed on the ultrasonic fingerprint chip 1, wherein the piezoelectric transducer 2 includes a piezoelectric layer 21, an upper electrode 22, and a lower electrode 23 disposed below the piezoelectric layer 21, and in order to connect the upper electrode 22 to a Bonding Pad (Bonding Pad) 12 of the ultrasonic fingerprint chip 1, the shape of the upper electrode 22 is specially designed, the upper electrode 22 includes a first electrode portion 221 disposed above the piezoelectric layer 21 and a second electrode portion 222 extending to the upper surface of the ultrasonic fingerprint chip 1 across the piezoelectric layer 21, the first electrode portion 221 is planar, the second electrode portion 222 is L-shaped, the second electrode portion 222 is connected to an upper electrode driving signal line 3 disposed on the upper surface of the ultrasonic fingerprint chip 1, and the upper electrode driving signal line 3 is connected to the Bonding Pad 12, thereby realizing connection of the upper electrode 22 and the Bonding Pad 12. This connection has the following disadvantages: the second electrode portion 222 of the upper electrode 22 is L-shaped, has abrupt changes in boundary, and the transmission of ultrasonic waves at this position can generate diffraction voiceprint, so that water ripple appears near this position in the image, and interference is caused to the image; the upper electrode driving signal line 3 needs to be connected with high voltage during ultrasonic wave emission, so that the chip area of the part of the upper electrode driving signal line 3 needs to be clear, the chip area of the part is wasted, and the cost is increased; the ESD (Electrostatic Discharge ) withstand voltage of the upper electrode driving signal line 3 may be weak.

Disclosure of Invention

Aiming at the defects of the prior art, the invention innovatively provides an ultrasonic fingerprint identification device and electronic equipment, wherein the first conducting strip on the surface of a connecting circuit is electrically connected with the upper surface of an upper electrode, and the second conducting strip on the surface of the connecting circuit is electrically connected with an ultrasonic fingerprint chip, so that the connection between the upper electrode and the ultrasonic fingerprint chip is realized, the upper electrode is only arranged above a piezoelectric layer and does not need to cross the part of the piezoelectric layer, and the problem of corner diffraction ripple in an image is effectively solved; the upper electrode driving signal wire is omitted, the occupied space of the electrode driving signal wire is not required to be arranged on the ultrasonic fingerprint chip, the area can be reduced, and the cost is reduced; the problem of the ESD voltage difference resistance of the upper electrode driving signal line is solved.

To achieve the above technical object, a first aspect of the present invention discloses an ultrasonic fingerprint identification device, comprising: the ultrasonic fingerprint chip, the piezoelectric transducer and the connecting circuit;

The piezoelectric transducer is arranged above the ultrasonic fingerprint chip and comprises a piezoelectric layer, an upper electrode positioned above the piezoelectric layer and a lower electrode positioned below the piezoelectric layer;

the surface of the connecting circuit is provided with a first conducting strip and a second conducting strip, the first conducting strip is electrically connected with the upper surface of the upper electrode, and the second conducting strip is electrically connected with the ultrasonic fingerprint chip.

Further, the first conductive sheet is disposed on an upper surface or a lower surface of the connection line.

Further, the second conductive sheet is arranged on the lower surface of the connecting circuit, and the second conductive sheet is electrically connected with the bonding pad on the upper surface of the ultrasonic fingerprint chip.

Further, the first conductive sheet and the upper electrode are electrically connected through a conductive adhesive layer, and/or the second conductive sheet and the ultrasonic fingerprint chip are electrically connected through a conductive adhesive layer.

Further, the first conductive sheet and the upper electrode are electrically connected through the structural adhesive layers and the conductive adhesive layers which are distributed in a staggered manner, and/or the second conductive sheet and the ultrasonic fingerprint chip are electrically connected through the structural adhesive layers and the conductive adhesive layers which are distributed in a staggered manner.

Further, the upper surface of the upper electrode is a plane or a step surface, and the lower surface of the upper electrode is a plane; when the upper surface of the upper electrode is a step surface, the part of the upper surface of the upper electrode, which is electrically connected with the first conductive sheet, is lower than other parts.

Further, the length of the first conductive sheet is greater than 30um, the horizontal distance between the first conductive sheet and the lower electrode is greater than 50um, and the horizontal distance between the first conductive sheet and the upper electrode, which is close to the edge of the connecting circuit, is greater than 30um.

Further, a protection layer is arranged on the upper surface of the upper electrode at a part which is not electrically connected with the first conductive sheet, and the horizontal distance between the first conductive sheet and the protection layer is larger than 30um.

Further, a first auxiliary positioning hole is formed in the connecting line, and second auxiliary positioning holes corresponding to the first auxiliary positioning holes in number are formed in the ultrasonic fingerprint chip.

Further, the connection circuit includes a first connection portion provided with the first conductive sheet, a second connection portion provided with the second conductive sheet, and a third connection portion connecting the first connection portion and the second connection portion.

Further, a shielding electrode is further arranged on the upper surface of the ultrasonic fingerprint chip, and the shielding electrode is arranged along the periphery of the lower electrode.

Further, the upper surface of the ultrasonic fingerprint chip is covered with a passivation layer, and windows are arranged at positions of the passivation layer corresponding to the shielding electrode and the lower electrode.

In order to achieve the above technical purpose, a second aspect of the present invention discloses an electronic device, which comprises a display screen and the ultrasonic fingerprint recognition device of the first aspect, wherein the ultrasonic fingerprint recognition device is disposed below the display screen.

The beneficial effects of the invention are as follows:

According to the ultrasonic fingerprint identification device, the first conducting strip on the surface of the connecting circuit is electrically connected with the upper surface of the upper electrode, and the second conducting strip on the surface of the connecting circuit is electrically connected with the ultrasonic fingerprint chip, so that the connection between the upper electrode and the ultrasonic fingerprint chip is realized, the upper electrode is only arranged above the piezoelectric layer, and the problem of corner diffraction ripple in an image is effectively solved without crossing the part of the piezoelectric layer; the upper electrode driving signal wire is omitted, the occupied space of the electrode driving signal wire is not required to be arranged on the ultrasonic fingerprint chip, the area can be reduced, and the cost is reduced; the problem of the ESD voltage difference resistance of the upper electrode driving signal line is solved.

Drawings

Fig. 1 is a plan view of a conventional ultrasonic fingerprint sensor chip.

Fig. 2 is a cross-sectional view of a conventional ultrasonic fingerprint sensor chip.

Fig. 3 is a plan view of an ultrasonic fingerprint recognition device according to a first embodiment of the present invention.

Fig. 4 is a sectional view of an ultrasonic fingerprint recognition device according to a first embodiment of the present invention.

Fig. 5 is a sectional view of an ultrasonic fingerprint recognition device according to a second embodiment of the present invention.

Fig. 6 is a sectional view of an ultrasonic fingerprint recognition device according to a third embodiment of the present invention.

Fig. 7 is a plan view of an ultrasonic fingerprint recognition device according to a fourth embodiment of the present invention.

Fig. 8 is a schematic block diagram of an electronic device of an embodiment of the invention.

In the drawing the view of the figure,

1. An ultrasonic fingerprint chip; 11. a signal receiving circuit; 12. a bonding pad; 2. a piezoelectric transducer; 21. a piezoelectric layer; 22. an upper electrode; 221. a first electrode portion; 222. a second electrode portion; 23. a lower electrode; 3. an upper electrode driving signal line; 4. a connection line; 41. a first conductive sheet; 42. a second conductive sheet; 43. a first auxiliary positioning hole; 44. a first connection portion; 45. a second connecting portion; 46. a third connecting portion; 5. a conductive adhesive layer; 6. a structural adhesive layer; 7. a shielding electrode; 8. a passivation layer; 9. a protective layer; 10. an ultrasonic fingerprint identification device; 20. and a display screen.

Detailed Description

The ultrasonic fingerprint recognition device and the electronic equipment provided by the invention are explained and illustrated in detail below with reference to the attached drawings.

The embodiment specifically discloses an ultrasonic fingerprint identification device, which can be arranged below a display screen 20 of an electronic device to realize on-screen ultrasonic fingerprint identification. As shown in fig. 3-7, the ultrasonic fingerprint recognition device comprises an ultrasonic fingerprint chip 1, a piezoelectric transducer 2 and a connecting circuit 4, wherein the piezoelectric transducer 2 is arranged above the ultrasonic fingerprint chip 1, the piezoelectric transducer 2 comprises a piezoelectric layer 21, an upper electrode 22 positioned above the piezoelectric layer 21 and a lower electrode 23 positioned below the piezoelectric layer 21, the lower electrode 23 is arranged on the upper surface of the ultrasonic fingerprint chip 1, a first conductive sheet 41 and a second conductive sheet 42 are arranged on the surface of the connecting circuit 4, the first conductive sheet 41 is electrically connected with the upper surface of the upper electrode 22, and the second conductive sheet 42 is electrically connected with the ultrasonic fingerprint chip 1. In this embodiment, the ultrasonic fingerprint chip 1 is provided with a signal receiving circuit 11, the signal receiving circuit 11 is electrically connected with a lower electrode 23, the connection circuit 4 can be connected with an external driving circuit, the driving circuit is used for generating an excitation signal and loading the excitation signal to an upper electrode 22 to excite a piezoelectric layer 21 to send an ultrasonic signal to a finger above a display screen 20, the signal receiving circuit 11 of the ultrasonic fingerprint chip 1 is connected with the lower electrode 23 to receive an ultrasonic detection signal generated between the upper electrode 22 and the lower electrode 23 when the ultrasonic signal returned by the finger acts on the piezoelectric layer 21, and the ultrasonic detection signal is used for acquiring a fingerprint image of the finger.

In the present embodiment, the ultrasonic fingerprint chip 1 is a complementary metal-Oxide-Semiconductor Transistor (CMOS) chip, and the simplification and miniaturization of the ultrasonic fingerprint identification device are realized while ensuring the signal processing sensitivity. The upper electrode 22 is a metal layer or a metal paste coating, such as a silver paste coating, formed on the upper surface of the piezoelectric layer 21. The lower electrode 23 may be an electrode array formed by a plurality of pixel electrodes, or may be a monolithic electrode plate, and the specific form may be selectively set according to the actual recognition environment. In the case that the lower electrode 23 is an electrode array, an ultrasonic fingerprint signal returned by the finger will generate an electrical signal between each pixel electrode in the electrode arrays of the upper electrode 22 and the lower electrode 23, and the electrical signal corresponding to each pixel electrode is taken as a pixel value of one pixel in the fingerprint pattern, and can be acquired and processed separately. The piezoelectric layer 21 is a piezoelectric film, and is formed of a material having a piezoelectric effect, such as polyvinylidene fluoride (PVDF) or polyvinylidene fluoride-trifluoroethylene copolymer (PVDF-TrFE). The connection circuit 4 may be a printed circuit board, a flexible circuit board (flexible printed circuit, FPC) or other circuit board having conductive lines, preferably a flexible circuit board in the present application, which may be provided in a suitable shape as needed so that the thickness of the ultrasonic fingerprint recognition device may be reduced.

Optionally, the first conductive sheet 41 and the second conductive sheet 42 are gold fingers, which can meet the related requirements of connection reliability.

In the embodiment, the upper surface of the upper electrode 22 and the ultrasonic fingerprint chip 1 are respectively electrically connected through the conductive sheet on the surface of the connecting line 4, so that the upper electrode 22 and the ultrasonic fingerprint chip 1 are electrically connected, the upper electrode 22 is only arranged above the piezoelectric layer 21, the upper electrode 22 does not need to be provided with a part extending across the piezoelectric layer 21 and in the direction of the upward electrode driving signal line 3, namely, the second electrode part 222 in fig. 1 and 2 is not provided, and the problem of corner diffraction ripple in an image is effectively solved; the upper electrode driving signal wire 3 is omitted, the ultrasonic fingerprint chip 1 can omit the part occupied by the upper electrode driving signal wire 3, the area can be reduced, and the cost is reduced; and the problem of ESD withstand voltage of the upper electrode driving signal line 3 is successfully eliminated.

In some embodiments, the first conductive sheet 41 is disposed on the upper surface or the lower surface of the connection line 4. As shown in fig. 4 and 5, the first conductive sheet 41 is provided on the lower surface of the connection wiring 4; as shown in fig. 6, the first conductive sheet 41 is provided on the upper surface of the connection line 4, and at this time, the area of the piezoelectric layer 21 may be appropriately increased for supporting the connection line 4. The first conductive sheet 41 is designed in such a way that the flexibility of the connection mode is improved, the position of the first conductive sheet 41 can be set according to actual requirements, and the thickness of the ultrasonic fingerprint identification device is reduced; and the upper electrode 22 is disposed only above the piezoelectric layer 21 regardless of whether the first conductive sheet 41 is disposed on the upper surface or the lower surface, there is no problem of corner diffraction ripple in the image.

Optionally, a second conductive sheet 42 is disposed on the lower surface of the connection circuit 4, and the second conductive sheet 42 is electrically connected to the pad 12 on the upper surface of the ultrasonic fingerprint chip 1, so as to reduce the thickness of the ultrasonic fingerprint recognition device.

In some embodiments, the first conductive sheet 41 is electrically connected to the upper electrode 22 through the conductive adhesive layer 5, and/or the second conductive sheet 42 is electrically connected to the ultrasonic fingerprint chip 1 through the conductive adhesive layer 5. As shown in fig. 4 and 5, when the first conductive sheet 41 is disposed on the lower surface of the connection line 4, a conductive adhesive layer 5 is disposed between the lower surface of the first conductive sheet 41 and the upper surface of the upper electrode 22, so as to electrically connect the first conductive sheet 41 and the upper electrode 22; as shown in fig. 6, when the first conductive sheet 41 is disposed on the upper surface of the connection circuit 4, the conductive adhesive layer 5 is in an inverted L shape, the bottom surface of the conductive adhesive layer 5 is adhered to the upper surface of the upper electrode 22, and the bottom surface of the horizontal section of the conductive adhesive layer 5 is adhered to the upper surface of the first conductive sheet 41, so as to electrically connect the first conductive sheet 41 and the upper electrode 22. As shown in fig. 4-6, a conductive adhesive layer 5 is disposed between the lower surface of the second conductive sheet 42 and the upper surface of the bonding pad 12 of the ultrasonic fingerprint chip 1, so as to electrically connect the second conductive sheet 42 and the ultrasonic fingerprint chip 1.

In some embodiments, the first conductive sheet 41 is electrically connected to the upper electrode 22 through the structural adhesive layers 6 and 5 that are staggered, and/or the second conductive sheet 42 is electrically connected to the ultrasonic fingerprint chip 1 through the structural adhesive layers 6 and 5 that are staggered. As shown in fig. 7, the first conductive sheet 41 and the upper electrode 22 are electrically connected through the structural adhesive layers 6 and the conductive adhesive layers 5 which are distributed in a staggered manner, 3 structural adhesive layers 6 are arranged in the horizontal direction, one conductive adhesive layer 5 is arranged between every two structural adhesive layers 6, and the bonding force between the first conductive sheet 41 and the upper electrode 22 is enhanced on the premise of not affecting the conductive connection. The staggered structural adhesive layers 6 and the conductive adhesive layers 5 are arranged between the lower surface of the second conductive sheet 42 and the upper surface of the bonding pad 12 of the ultrasonic fingerprint chip 1, so that the second conductive sheet 42 is electrically connected with the ultrasonic fingerprint chip 1, and the thickness of the ultrasonic fingerprint identification device is reduced.

Alternatively, the material of the conductive paste layer 5 is preferably silver paste, ACF (Anisotropic Conductive Film ) paste, or conductive ink.

In some embodiments, the upper surface of the upper electrode 22 is a planar or stepped surface, and the lower surface of the upper electrode 22 is a planar surface; when the upper surface of the upper electrode 22 is a stepped surface, the portion of the upper surface of the upper electrode 22 electrically connected to the first conductive sheet 41 is lower than the other portions. As shown in fig. 4, the upper surface of the upper electrode 22 is a plane, and as shown in fig. 5 and 6, the upper surface of the upper electrode 22 is a stepped surface, and the portion to be connected with the first conductive sheet 41 is arranged to be lower, so that the thickness of the entire ultrasonic fingerprint recognition device can be effectively reduced.

Optionally, the length b of the first conductive sheet 41 is greater than 30um, the horizontal distance d between the first conductive sheet 41 and the lower electrode 23 is greater than 50um, the horizontal distance c between the first conductive sheet 41 and the upper electrode 22 near the edge of the connection circuit 4 is greater than 30um, and the safe distance between each component is ensured while the area of the ultrasonic fingerprint identification device is reduced as much as possible.

Optionally, a portion of the upper surface of the upper electrode 22 not electrically connected to the first conductive sheet 41 is provided with the protective layer 9, and a horizontal distance a between the first conductive sheet 41 and the protective layer 9 is greater than 30um. The protection layer 9 protects the upper electrode 22 from oxidation or damage, and the connection circuit 4, the conductive adhesive layer 5, or the structural adhesive layer 6 and the conductive adhesive layer 5 which are distributed in a staggered manner are arranged above the part of the upper electrode 22 electrically connected with the first conductive sheet 41, so that the upper electrode 22 can be protected, and the service life of the ultrasonic fingerprint identification device is prolonged. Preferably, the material of the protective layer 9 is silicon nitride.

Optionally, as shown in fig. 3 and 7, a first auxiliary positioning hole 43 is provided on the connection circuit 4, and second auxiliary positioning holes (not shown in the figure) corresponding to the positions and the numbers of the first auxiliary positioning holes 43 are provided on the ultrasonic fingerprint chip 1, and by aligning the first auxiliary positioning holes 43 with the second auxiliary positioning holes corresponding to the positions, the first conductive sheet 41 and the upper electrode 22, and the second conductive sheet 42 and the bonding pad 12 can be aligned accurately, so that the safe distance between each component is maintained, and the accuracy is improved. Preferably, the number of the first auxiliary positioning holes 43 and the second auxiliary positioning holes is at least two, and one first auxiliary positioning hole 43 is arranged on each side of the first conductive sheet 41.

Alternatively, as shown in fig. 3 and 7, the connection line 4 includes a first connection portion 44 provided with the first conductive sheet 41, a second connection portion 45 provided with the second conductive sheet 42, and a third connection portion 46 connecting the first connection portion 44 and the second connection portion 45. Preferably, both ends of the third connection portion 46 are connected to the side portion of the first connection portion 44 and the side portion of the second connection portion 45, respectively, and the connection line 4 has a C-shape in plan view. The third connection portion 46 may be connected to other positions of the first connection portion 44 and the second connection portion 45 as long as the electrical connection with the first conductive sheet 41 and the second conductive sheet 42 can be achieved. As shown in fig. 4 to 6, the third connecting portion 46 has a longitudinal cross-sectional shape of an inclined shape or a bent shape with an inclined middle and horizontal ends, and the specific shape is set according to actual production requirements, so that the thickness of the ultrasonic fingerprint recognition device is reduced as much as possible.

Optionally, the upper surface of the ultrasonic fingerprint chip 1 is further provided with a shielding electrode 7, and the shielding electrode 7 is arranged along the periphery of the lower electrode 23 and is used for improving the uneven electric field of the edge area of the lower electrode 23 and improving the sensitivity of signal transmission and reception of the edge area of the lower electrode 23. The shielding electrode 7 is also capable of preventing external interference signals from being coupled to the lower electrode 23 through the edge region of the lower electrode 23, avoiding interference signals from affecting the reception sensitivity. As shown in fig. 4,5 and 6, the shielding electrode 7 is disposed on the right side of the lower electrode 23. In practice, the shielding electrode 7 may also be provided on the other side of the lower electrode 23 or around the lower electrode 23. The specific arrangement form of the shielding electrode 7 is flexibly arranged according to the installation position of the lower electrode 23 on the ultrasonic fingerprint chip 1.

Optionally, the upper surface of the ultrasonic fingerprint chip 1 is covered with a passivation layer 8, and windows are arranged at positions of the passivation layer 8 corresponding to the shielding electrode 7 and the lower electrode 23, so that the electrical connection between the piezoelectric layer 21 and the lower electrode 23 and between the passivation layer 8 and the shielding electrode 7 is ensured. The passivation layer 8 protects the ultrasonic fingerprint chip 1 from oxidation or damage, thereby prolonging the service life of the ultrasonic fingerprint recognition device. Preferably, the passivation layer 8 is made of silicon nitride.

According to the application, the connecting circuit 4 is respectively connected with the upper surface of the upper electrode 22 and the bonding pad 12 of the ultrasonic fingerprint chip 1 through the conductive sheet of the connecting circuit 4, so that the upper electrode 22 is connected with the ultrasonic fingerprint chip 1, the upper electrode 22 is only arranged above the piezoelectric layer 21, the piezoelectric layer 21 does not need to be extended, the special shape design is not needed, the problem of corner diffraction ripple in an image is effectively solved, the area of the ultrasonic fingerprint chip 1 can be reduced on the premise of ensuring the safe spacing of each component, the cost is reduced, and the problem of ESD pressure resistance difference does not occur.

The application also discloses an electronic device, as shown in fig. 8, comprising a display screen 20 and the ultrasonic fingerprint identification device 10 according to the above embodiment, wherein the ultrasonic fingerprint identification device 10 is arranged below the display screen 20, the display screen 20 is used for providing a pressing interface for a user finger and receiving the pressing of the user finger, and the ultrasonic fingerprint identification device 10 is used for identifying the fingerprint of the user finger pressed on the display screen 20, so that the ultrasonic fingerprint identification under the screen is realized.

The electronic device may be a portable or mobile computing device such as a terminal device, a mobile phone, a tablet computer, a notebook computer, a desktop computer, a game device, an on-board electronic device, or a wearable intelligent device, and other electronic devices such as an electronic database, an automobile, and a bank automatic teller machine (Automated TELLER MACHINE, ATM). Wearable smart devices include devices that are fully functional, large in size, and that can perform complete or partial functions independent of a smart phone, such as smart watches or smart glasses, and devices that focus only on certain types of application functions and that need to be used with other devices such as smart phones, such as various types of smart bracelets, smart jewelry, and the like.

In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings are merely for convenience in describing the present invention and simplifying the description, and do not indicate or imply that the device or element being referred to must have a specific orientation, be configured and operated in a specific orientation, and therefore should not be construed as limiting the present invention.

In the present invention, unless explicitly specified and limited otherwise, the terms "mounted," "connected," "secured," and the like are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally formed; can be mechanically or electrically connected; either directly or indirectly, through intermediaries, or both, may be in communication with each other or in interaction with each other, unless expressly defined otherwise. The specific meaning of the above terms in the present invention can be understood by those of ordinary skill in the art according to the specific circumstances.

In the description of the present specification, a description referring to the terms "present embodiment," "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the present invention. In this specification, schematic representations of the above terms are not necessarily directed to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any at least one embodiment or example. Furthermore, the different embodiments or examples described in this specification and the features of the different embodiments or examples may be combined and combined by those skilled in the art without contradiction.

Furthermore, the terms "first," "second," and the like, are used for descriptive purposes only and are not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include at least one such feature. In the description of the present invention, the meaning of "plurality" means at least two, for example, two, three, etc., unless specifically defined otherwise.

The above description is only of the preferred embodiments of the present invention, and is not intended to limit the invention, but any modifications, equivalents, and simple improvements made within the spirit of the present invention should be included in the scope of the present invention.

Claims (13)

1. An ultrasonic fingerprint recognition device, comprising: an ultrasonic fingerprint chip (1), a piezoelectric transducer (2) and a connecting circuit (4);

The piezoelectric transducer (2) is arranged above the ultrasonic fingerprint chip (1), and the piezoelectric transducer (2) comprises a piezoelectric layer (21), an upper electrode (22) arranged above the piezoelectric layer (21) and a lower electrode (23) arranged below the piezoelectric layer (21);

The surface of the connecting circuit (4) is provided with a first conducting strip (41) and a second conducting strip (42), the first conducting strip (41) is electrically connected with the upper surface of the upper electrode (22), and the second conducting strip (42) is electrically connected with the ultrasonic fingerprint chip (1).

2. The ultrasonic fingerprint recognition device according to claim 1, wherein the first conductive sheet (41) is provided on an upper surface or a lower surface of the connection line (4).

3. The ultrasonic fingerprint recognition device according to claim 1, wherein the second conductive sheet (42) is disposed on a lower surface of the connection line (4), and the second conductive sheet (42) is electrically connected to a pad (12) on an upper surface of the ultrasonic fingerprint chip (1).

4. An ultrasound fingerprint recognition device as claimed in any one of claims 1-3, characterized in that the first conductive sheet (41) is electrically connected to the upper electrode (22) by means of a conductive glue layer (5) and/or the second conductive sheet (42) is electrically connected to the ultrasound fingerprint chip (1) by means of a conductive glue layer (5).

5. An ultrasound fingerprint recognition device as claimed in any one of claims 1-3, characterized in that the first conductive sheet (41) is electrically connected to the upper electrode (22) by means of a staggered arrangement of structural adhesive layers (6) and conductive adhesive layers (5), and/or the second conductive sheet (42) is electrically connected to the ultrasound fingerprint chip (1) by means of a staggered arrangement of structural adhesive layers (6) and conductive adhesive layers (5).

6. The ultrasonic fingerprint recognition device according to claim 1 or 2, wherein an upper surface of the upper electrode (22) is a plane or a step surface, and a lower surface of the upper electrode (22) is a plane; when the upper surface of the upper electrode (22) is a step surface, the portion of the upper surface of the upper electrode (22) electrically connected to the first conductive sheet (41) is lower than the other portions.

7. The ultrasonic fingerprint recognition device according to claim 1, wherein the length of the first conductive sheet (41) is greater than 30um, the horizontal distance between the first conductive sheet (41) and the lower electrode (23) is greater than 50um, and the horizontal distance between the first conductive sheet (41) and the upper electrode (22) near the edge of the connection line (4) is greater than 30um.

8. The ultrasonic fingerprint recognition device according to claim 1 or 7, wherein a portion of the upper surface of the upper electrode (22) not electrically connected to the first conductive sheet (41) is provided with a protective layer (9), and a horizontal distance between the first conductive sheet (41) and the protective layer (9) is greater than 30um.

9. The ultrasonic fingerprint identification device according to claim 1, wherein the connecting line (4) is provided with first auxiliary positioning holes (43), and the ultrasonic fingerprint chip (1) is provided with second auxiliary positioning holes corresponding to the first auxiliary positioning holes (43) in position and number.

10. The ultrasonic fingerprint recognition device according to claim 1 or 9, wherein the connection line (4) includes a first connection portion (44) provided with the first conductive sheet (41), a second connection portion (45) provided with the second conductive sheet (42), and a third connection portion (46) connecting the first connection portion (44) and the second connection portion (45).

11. The ultrasonic fingerprint recognition device according to claim 1, wherein the upper surface of the ultrasonic fingerprint chip (1) is further provided with a shielding electrode (7), and the shielding electrode (7) is disposed along the periphery of the lower electrode (23).

12. The ultrasonic fingerprint identification device according to claim 11, characterized in that the upper surface of the ultrasonic fingerprint chip (1) is covered with a passivation layer (8), and the passivation layer (8) is provided with windows corresponding to the shielding electrode (7) and the lower electrode (23).

13. An electronic device, characterized by comprising a display screen (20) and an ultrasonic fingerprint recognition device (10) according to any one of claims 1-12, said ultrasonic fingerprint recognition device (10) being arranged below said display screen (20).