Ultrasonic sensor system and electronic equipment

Abstract

The embodiment of the utility model relates to the field of ultrasonic fingerprint sensors, and discloses an ultrasonic sensor system and electronic equipment. The ultrasonic sensor system comprises an ultrasonic fingerprint identification module, a matching layer and a screen or a cover plate, the matching layer is clamped between the ultrasonic fingerprint identification module and the screen or the cover plate; the matching layer at least comprises a first subarea and a second subarea which are not overlapped in position, the first subarea and the second subarea have different acoustic impedance characteristics respectively, the resonant frequency of one of the first subarea and the second subarea is matched with the skin epidermis layer, and the resonant frequency of the other one of the first subarea and the second subarea is matched with other structural layers of the skin; the first subarea and the second subarea have the same thickness, and the direction of the thickness is the direction of the vertical distance between the ultrasonic fingerprint identification module and the screen or the cover plate. The safety verification of the detection of the at least two structural layer features of the skin is realized, and the reliability of the safety verification is improved.

Description

TECHNICAL FIELD

[0001] The utility model relates to the field of ultrasonic sensor, especially relates to an ultrasonic sensor system and electronic equipment. BACKGROUND

[0002] The ultrasonic sensor works by using the piezoelectric and inverse piezoelectric characteristics of piezoelectric materials, on the one hand, by the inverse piezoelectric effect, the high voltage excitation sensor output by the drive circuit emits ultrasonic signals to the outside, on the other hand, through the piezoelectric effect, the ultrasonic signals reflected from the outside are converted into electrical signals, thereby obtaining the outside sensing surface information. After decades of development, the current ultrasonic fingerprint sensor can be widely used in medical imaging, structure detection, biometric identification field. For example, the ultrasonic sensor is applied to an ultrasonic fingerprint module, which is arranged in a specific area of the screen of electronic equipment including but not limited to a smart phone, can be used for fingerprint identification, realizes user identity authentication, enhances the anti-interference and security of the product.

[0003] The inventor finds that the current ultrasonic fingerprint sensor applied to fingerprint identification at least has the following disadvantages: since the fingerprint can usually be imitated, for example, using a finger-shaped object or a finger sleeve including silicone rubber, gel, glycerol, etc. on the outer surface of which a fingerprint pattern of a legal user is forged, therefore, the security verification by simply identifying the fingerprint pattern has poor reliability, and it is easy to cause information loss or illegal authorization problems. UTILITY MODEL CONTENT

[0004] The purpose of the embodiment of the utility model is to provide an ultrasonic sensor system and electronic equipment, by arranging the matching layer with multiple partitions, different frequency ultrasonic signals are emitted at the same time, and then the detection of the characteristics of at least two structure layers in the skin is completed, the security verification is realized by detecting the characteristics of at least two structure layers, and the reliability of the security verification is improved.

[0005] In order to solve the above technical problems, the embodiment of the utility model provides an ultrasonic sensor system, which comprises: an ultrasonic fingerprint identification module, a matching layer, and a screen or a cover plate; the matching layer is arranged between the ultrasonic fingerprint identification module and the screen or the cover plate; the matching layer comprises at least a first partition and a second partition which are not overlapped with each other, wherein the first partition and the second partition have different acoustic impedance characteristics respectively, the resonant frequency of one of the first partition and the second partition is matched with the skin epidermis layer, and the resonant frequency of the other one is matched with other structure layers of the skin; the first partition and the second partition are respectively attached to different areas of the surface of the ultrasonic fingerprint identification module, and the thickness of the first partition and the second partition is the same, and the thickness direction is the vertical distance direction between the ultrasonic fingerprint identification module and the screen or the cover plate.

[0006] The embodiment of the utility model discloses still provide an electronic equipment, include: above-mentioned ultrasonic sensor system.

[0007] The utility model discloses embodiment relative to prior art, the matching layer of clamping between ultrasonic fingerprint identification module and screen or cover plate includes at least first partition and second partition, because first partition and second partition respectively with the different area of ultrasonic fingerprint identification module surface is in line with, position does not overlap each other, and first partition and second partition respectively have different acoustic impedance characteristics, the resonant frequency of one of first partition and second partition is matched with the skin epidermis layer, and the resonant frequency of another is matched with the other structure layer of skin. Therefore, the signal that ultrasonic signal that ultrasonic fingerprint identification module sends is exported respectively with the different frequency response effect of first partition and second partition, therefore can detect the feature of skin epidermis layer and the feature of other structure layer except epidermis layer simultaneously. Through the detection of at least two structure layer features realizes security authentication, improves the reliability of security authentication.

[0008] In addition, the first partition and the second partition are both multi-layer structures, and the first partition and the second partition each include a first glue layer, a metal layer and a second glue layer arranged in sequence from the ultrasonic fingerprint identification module to the screen or the cover plate.

[0009] In addition, the first glue layer in the first partition and the second partition respectively has the same thickness, the metal layer in the first partition and the second partition respectively has the same thickness, and the second glue layer in the first partition and the second partition respectively has the same thickness.

[0010] In addition, the second glue layer in the first partition and the second partition respectively has different material acoustic impedances.

[0011] In addition, the material acoustic impedance of the second glue layer in the first partition and the second partition is 2.28E6 Rayl and 17.5E6 Rayl respectively.

[0012] In addition, the thickness of the first glue layer ranges from 1 micrometer to 10 micrometers, the thickness of the metal layer ranges from 5 micrometers to 50 micrometers, and the thickness of the second glue layer ranges from 1 micrometer to 40 micrometers.

[0013] In addition, the layout form of the first partition and the second partition is a side-by-side arrangement form or a ring distribution form.

[0014] In addition, the acoustic impedance of the first partition is smaller than the acoustic impedance of the second partition, the response effect of the first partition to a low-frequency signal is higher than the response effect of the first partition to a high-frequency signal, and the response effect of the second partition to a low-frequency signal is lower than the response effect of the second partition to a high-frequency signal.

[0015] In addition, the ultrasonic fingerprint identification module comprises, in sequence, a substrate, a bottom electrode, a piezoelectric layer, a top electrode and a protective layer; the screen or cover plate is fixed to the side of the ultrasonic fingerprint identification module close to the substrate, and the matching layer is arranged between the substrate and the screen or cover plate, and the matching layer is attached to the substrate. BRIEF DESCRIPTION OF DRAWINGS

[0016] One or more embodiments are illustrated by way of example in the figures that form a part of this patent document, these example are not to be construed as limiting the embodiments, elements having the same reference numbers in figures are to be interpreted as the same elements, unless otherwise specifically noted, the figures in the drawings are not to scale limitation.

[0017] Figure 1 is a structural schematic diagram of an ultrasonic sensor system according to an embodiment of the present scheme;

[0018] Figure 2 is a simple structural schematic diagram of a user's finger skin according to an embodiment of the present scheme;

[0019] Figure 3 is a frequency response curve diagram of a first subzone in an ultrasonic sensor system according to an embodiment of the present scheme;

[0020] Figure 4 is a frequency response curve diagram of a second subzone in an ultrasonic sensor system according to an embodiment of the present scheme;

[0021] Figure 5 is a layout structural schematic diagram of a first subzone and a second subzone in an ultrasonic sensor system according to an embodiment of the present scheme;

[0022] Figure 6 is a layout structural schematic diagram of a first subzone and a second subzone in an ultrasonic sensor system according to an embodiment of the present scheme;

[0023] Figure 7 is a layout structural schematic diagram of a first subzone and a second subzone in an ultrasonic sensor system according to an embodiment of the present scheme;

[0024] Figure 8 is a layout structural schematic diagram of a plurality of subzones in an ultrasonic sensor system according to an embodiment of the present scheme;

[0025] Figure 9 is a structural schematic diagram of an ultrasonic fingerprint identification module in an ultrasonic sensor system according to an embodiment of the present scheme;

[0026] Figure 10 is a structural schematic diagram of an ultrasonic fingerprint identification module in an ultrasonic sensor system according to an embodiment of the present scheme;

[0027] Figure 11 is a flow chart of a fingerprint identification detection method according to an embodiment of the present solution. DETAILED DESCRIPTION

[0028] In order to make the purposes, technical solutions and advantages of the embodiments of the present application clearer, the embodiments of the present application will be described in detail below with reference to the drawings. However, those skilled in the art can understand that, in the embodiments of the present application, many technical details are proposed in order to make the readers better understand the present application. However, even without these technical details and various changes and modifications based on the following embodiments, the technical solutions claimed by the present application can be implemented.

[0029] The division of the following embodiments is for the convenience of description, and should not constitute any limitation on the specific implementation of the present application, and the embodiments can be combined and referenced with each other on the premise of no contradiction.

[0030] Embodiments of the present application relate to an ultrasonic sensor system, as shown in Figure 1 The ultrasonic sensor system comprises an ultrasonic fingerprint identification module 1, a matching layer 2, and a screen or cover plate 3; the matching layer 2 is arranged between the ultrasonic fingerprint identification module 1 and the screen or cover plate 3; the matching layer 2 comprises at least a first sub-area 21 and a second sub-area 22 which do not overlap with each other, wherein the first sub-area 21 and the second sub-area 22 have different acoustic impedance characteristics, the resonance frequency of one of the first sub-area 21 and the second sub-area 22 matches the skin epidermis layer, and the resonance frequency of the other sub-area matches the other structure layer of the skin; the first sub-area 21 and the second sub-area 22 are respectively attached to different areas of the surface of the ultrasonic fingerprint identification module 1, and the thicknesses of the first sub-area 21 and the second sub-area 22 are the same, and the thickness direction is the direction of the vertical distance between the ultrasonic fingerprint identification module 1 and the screen or cover plate 2.

[0031] When the ultrasonic sensor system is used for fingerprint identification, the user will press the finger onto the screen or cover plate, and the simplified structure of the skin of the user's finger is as shown in Figure 2 The skin of the finger close to the screen or cover plate is sequentially divided into epidermis layer, dermis layer and subcutaneous blood vessel layer structure in the direction away from the screen or cover plate, and the structural characteristics of different layers of the skin are different, so the frequency of the ultrasonic signal required for imaging the structural characteristics of different layers is different, for example, the epidermis fingerprint imaging often requires a relatively high resonance frequency, for example, 15MHz or higher; the sub-epidermis feature imaging often requires a relatively low frequency, for example, less than 12MHz. In the present case, the matching layer is divided into sub-areas, and the resonance frequency is matched for different structural layers of the skin, thereby realizing the collection and verification of the structural characteristics of different layers of the skin.

[0032] The utility model embodiment relative to prior art, the matching layer is sandwiched between ultrasonic fingerprint identification module and screen or cover plate, and the matching layer comprises at least first partition and second partition, because first partition and second partition respectively with the different area of ultrasonic fingerprint identification module surface is in conformity with, position does not overlap each other, and first partition and second partition respectively have different acoustic impedance characteristics, the resonant frequency of one of first partition and second partition is matched with skin epidermis layer, and the resonant frequency of another is matched with other structure layer of skin. Therefore, the signal that ultrasonic fingerprint identification module sends through the signal that first partition and second partition output respectively has different frequency response effect, so can detect the feature of skin epidermis layer and the feature of other structure layer except epidermis layer simultaneously. Through the detection of at least two structure layer characteristics, realize security authentication, improve the reliability of security authentication.

[0033] The first partition and the second partition in the utility model embodiment are all multilayer structures, as shown in Figure 1 For example, the first partition and the second partition all include three layers of structures (three layers of different base patterns as shown in Figure 1 The first glue layer, the metal layer and the second glue layer are sequentially arranged from the ultrasonic fingerprint identification module to the screen or the cover plate. The first glue layer is arranged close to the ultrasonic fingerprint identification module, and the second glue layer is arranged close to the screen or the cover plate. The first glue layer and the second glue layer change the acoustic impedance of the matching layer, and are conducive to the adhesion of the matching layer to the ultrasonic fingerprint identification module and the screen or the cover plate, and better fix the position of the matching layer.

[0034] The first glue layer and the second glue layer can use dry film adhesive, and the materials can be selected from epoxy resin, acrylic and the like. The metal layer can use one or more of aluminum (Al), copper (Cu), gold (Au), platinum (Pt), tin (Sn), nickel (Ni), silver (Ag) and the like. By adjusting the thickness or acoustic impedance characteristics of each layer of material of the first partition and the second partition, the multi-frequency signal output of the ultrasonic sensor system can be realized. When adjusting the thickness of each layer of material of the first partition and the second partition, the sum of the thickness of each layer of material of the first partition and the sum of the thickness of each layer of material of the second partition need to be kept the same, so that the ultrasonic signal of the ultrasonic fingerprint identification module can be vertically incident into the screen or the cover plate through the matching layer, avoiding the loss of the ultrasonic signal in the transmission process, and improving the imaging effect. The thickness of each layer of material in each partition can be set in the range of 1 micrometer to 10 micrometers for the first glue layer, 5 micrometers to 50 micrometers for the metal layer, and 1 micrometer to 40 micrometers for the second glue layer.

[0035] In order to make the first partition and the second partition have different acoustic impedance characteristics respectively, the matching layer parameters can be set by starting from the physical quantity affecting the acoustic impedance in the field of ultrasound. The acoustic impedance is a physical quantity describing the hindering effect of the medium on the propagation of ultrasonic waves, commonly represented by the symbol Z, and Rayl is used as the unit of acoustic impedance. The acoustic impedance is closely related to the density (p) of the material and the propagation speed (v) of sound in the material, and is commonly represented by the following formula:

[0036] Z = p * v;

[0037] Therefore, in practical applications, the material can be made to have different acoustic impedance characteristics by changing the composition or element ratio of the material.

[0038] The embodiment of the utility model provides a kind of control first partition and each corresponding material layer thickness of second partition is identical, only the way of adjusting the material density of each corresponding material layer, make different partition have different acoustic impedance characteristics. For example, the thickness of the first glue layer corresponding in the first partition and the second partition is identical, and is 5 microns;The thickness of the metal layer corresponding in the first partition and the second partition is identical, and is 18 microns;And the thickness of the second glue layer corresponding in the first partition and the second partition is identical, and is 35 microns. Only by changing the density of single-layer material layer or the density of multilayer material layer, the first partition and the second partition have different acoustic impedance characteristics. As can be set the material density of the second glue layer corresponding in the first partition and the second partition to 1200kg / m 3 And 9200kg / m 3 , So that its acoustic impedance is 2.28E6 Rayl and 17.5E6 Rayl respectively. The frequency response effect obtained by the above setting parameters experiment of the first partition and the second partition is as shown in Figures 3-4 , The acoustic impedance of the first partition is less than that of the second partition, the response effect of the first partition to low frequency signal is higher than that of the first partition to high frequency signal, and the response effect of the second partition to low frequency signal is lower than that of the second partition to high frequency signal. Assuming that the acoustic impedance value is lower than 5E6 Rayl is called low impedance, the output signal of the first partition with low impedance characteristics is dominated by low frequency, and high frequency signal is weak. The output signal of the second partition with high impedance characteristics is dominated by high frequency, and low frequency signal is weak. The first partition is suitable for imaging the dermis layer features and blood vessel structure distribution inside the skin structure, and the second partition is suitable for imaging the epidermis layer fingerprint features on the surface of the skin.

[0039] The layout form of the first partition and the second partition can be side-by-side arrangement or ring distribution. As shown in Figure 5 , The first partition 21 and the second partition 22 are arranged side by side, as shown in Figure 6The first partition 21 and the second partition 22 are arranged in an up-down and side-by-side manner, as shown in Figure 7 The first partition 21 surrounds the second partition 22, as shown. In addition, the matching layer can also be provided with more than two partitions, as shown in Figure 8 Four partitions are provided, i.e., the first partition 21, the second partition 22, the third partition 23 and the fourth partition 24, which together form a cross-shaped structure, as shown. The above-mentioned layout forms of the partitions and the settings of the number of partitions can be flexibly adjusted according to actual conditions, as shown in Figures 5-8 The electrode array of the ultrasonic fingerprint identification module is below each partition of the matching layer, and it is necessary to ensure that the positions of the matching layer and the electrode array overlap in the ultrasonic signal transmission direction, so that the ultrasonic signal can pass through the matching layer.

[0040] In addition, as shown in Figure 9 The ultrasonic fingerprint identification module 1 comprises, in sequence, a substrate 11, a bottom electrode 12, a piezoelectric layer 13, a top electrode 14 and a protective layer 15, and a pad area 16 is provided on the substrate 11. As shown in Figure 1 The screen or cover plate 3 is fixed to the side of the ultrasonic fingerprint identification module 1 close to the substrate 11, and the matching layer 2 is arranged between the substrate 11 and the screen or cover plate 3, and the matching layer 2 is attached to the substrate 11.

[0041] The bottom electrode, the piezoelectric layer, the top electrode and the protective layer together form an acoustic-electric conversion structure. When the ultrasonic fingerprint identification module is in an acoustic emission mode, the bottom electrode is grounded, and the top electrode is used to apply an excitation signal to excite the piezoelectric layer to emit an ultrasonic signal; when the ultrasonic fingerprint identification module is in an acoustic receiving mode, the top electrode is grounded, and the bottom electrode is used to receive the returned ultrasonic signal to generate a voltage echo signal between the top electrode and the bottom electrode. The top electrode partially overlaps the pad area to realize the extraction of the electrical signal, and the bottom electrode is connected to the pad area through internal wiring (not shown in the figure).

[0042] The thickness control range of each material stack in the ultrasonic fingerprint identification module includes: piezoelectric layer (5-30 microns (μm)), top electrode layer (0.1-30 μm), protective layer (5-40 μm), bottom electrode layer (0.01-1 μm), substrate layer (50-200 μm).

[0043] As shown in Figure 10As shown, the ultrasonic fingerprint identification module further comprises a flexible printed circuit board (FPC) 17 connected to the pad area, a reinforcing member 19, electronic components 18 and a connector 10 disposed on the flexible printed circuit board. The flexible printed circuit board is connected to the pad area by low-temperature bonding, and the bonding medium includes but is not limited to anisotropic conductive adhesive (ACF); the electronic components include but are not limited to passive devices such as inductors, capacitors and resistors, and active devices such as boost chips and signal preprocessing chips, which mainly provide excitation signals for the ultrasonic fingerprint identification module and pre-process the echo signals; the connector at the end of the FPC away from the ultrasonic sensor is used to connect to the master control chip of the back-end system to provide communication and interaction. The cover plate in the ultrasonic sensor system can be any suitable material that can be acoustically coupled to the ultrasonic fingerprint identification module system, for example, including plastic, ceramic, sapphire, metal and glass.

[0044] Another feasible embodiment of the utility model relates to an electronic device, comprising: the ultrasonic fingerprint identification module.

[0045] Compared with the related art, the electronic device provided in the embodiment of the utility model is provided with the ultrasonic fingerprint identification module provided in the foregoing embodiment, so it also has the technical effects provided in the foregoing embodiment, which will not be described here.

[0046] The following describes the fingerprint identification application mode of the electronic device and the ultrasonic fingerprint identification module provided in the utility model:

[0047] As shown in the embodiment, Figure 11 The control chip can be a logic device inside the ultrasonic sensor system, or one or more external general logic devices. In the embodiment, the control chip first configures the ultrasonic sensor into a transmission mode, then controls the ultrasonic sensor to emit a first ultrasonic wave, which can include a first frequency. Then the control chip controls the ultrasonic sensor to emit a second ultrasonic wave, which can include a second frequency. After the transmission is completed, the control chip configures the ultrasonic sensor into a receiving mode; the control chip first controls the ultrasonic sensor to receive the echo signal of the first ultrasonic wave, which comes from the reflection on the surface of the finger skin; then the control chip controls the ultrasonic sensor to receive the echo signal of the second ultrasonic wave, which comes from the reflection inside the finger skin; according to the first echo signal, the second echo signal or the combination of the two echo signals, the epidermal fingerprint and the subcutaneous feature are imaged at the same time, and the fingerprint feature is extracted to realize identity authentication.

[0048] Those skilled in the art can understand that the above embodiments are specific embodiments for implementing the utility model, and in actual application, various changes can be made in form and details without departing from the spirit and scope of the utility model.

Claims

1. An ultrasonic sensor system, characterized by The ultrasonic fingerprint identification module, the matching layer, and the screen or cover plate are included. The matching layer is arranged between the ultrasonic fingerprint identification module and the screen or cover plate. The matching layer includes a first sub-region and a second sub-region which are not overlapped with each other, and the first sub-region and the second sub-region have different acoustic impedance characteristics, one of the first sub-region and the second sub-region has a resonant frequency matched with a skin epidermis layer, and the other has a resonant frequency matched with other structure layers of the skin. The first sub-region and the second sub-region are respectively attached to different areas of the surface of the ultrasonic fingerprint identification module, and the first sub-region and the second sub-region have the same thickness, and the thickness direction is perpendicular to the distance between the ultrasonic fingerprint identification module and the screen or cover plate.

2. The ultrasonic sensor system according to claim 1, wherein The first sub-region and the second sub-region are both multi-layer structures, and each of the first sub-region and the second sub-region includes a first glue layer, a metal layer, and a second glue layer arranged in sequence from the ultrasonic fingerprint identification module to the screen or cover plate.

3. The ultrasonic sensor system according to claim 2, wherein The thickness of the first glue layer corresponding to the first sub-region and the second sub-region is the same, the thickness of the metal layer corresponding to the first sub-region and the second sub-region is the same, and the thickness of the second glue layer corresponding to the first sub-region and the second sub-region is the same. The material acoustic impedance of the second glue layer corresponding to the first sub-region and the second sub-region is different.

4. The ultrasonic sensor system of claim 3, wherein, The material acoustic impedance of the second glue layer corresponding to the first sub-region and the second sub-region is 2.28E6 Rayl and 17.5E6 Rayl respectively.

5. The ultrasonic sensor system of claim 4, wherein, The thickness of the first glue layer ranges from 1 micrometer to 10 micrometers, the thickness of the metal layer ranges from 5 micrometers to 50 micrometers, and the thickness of the second glue layer ranges from 1 micrometer to 40 micrometers.

6. The ultrasonic sensor system of claim 2, wherein, The layout form of the first sub-region and the second sub-region is side-by-side arrangement or ring distribution.

7. The ultrasonic sensor system of claim 1, wherein, The acoustic impedance of the first sub-region is smaller than that of the second sub-region, the response effect of the first sub-region to low-frequency signals is higher than that of the first sub-region to high-frequency signals, and the response effect of the second sub-region to low-frequency signals is lower than that of the second sub-region to high-frequency signals.

8. The ultrasonic sensor system of claim 1, wherein, 9. The ultrasonic sensor system according to any one of claims 1 to 8, wherein The ultrasonic fingerprint identification module includes a substrate, a bottom electrode, a piezoelectric layer, a top electrode, and a protective layer arranged in sequence. The screen or cover plate is fixed to the side of the ultrasonic fingerprint identification module close to the substrate, the matching layer is arranged between the substrate and the screen or cover plate, and the matching layer is attached to the substrate. The ultrasonic sensor system according to any one of claims 1 to 9.

10. An electronic device, comprising: ​ ​

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