Ultrasonic fingerprint identification module

Abstract

The invention relates to the field of fingerprint identification, and discloses an ultrasonic fingerprint identification module, which comprises a plurality of ultrasonic fingerprint sensor arrays arranged in an array, and is characterized in that each ultrasonic fingerprint sensor array comprises a plurality of ultrasonic fingerprint sensor array elements arranged in an array, and the ultrasonic fingerprint sensor array elements are ultrasonic fingerprint sensors; the ultrasonic fingerprint sensor comprises a silicon substrate and a micro-capacitance structure arranged on the silicon substrate, the micro-capacitance structure comprises a piezoelectric layer, a lower electrode arranged above the piezoelectric layer and an upper electrode arranged above the lower electrode, an insulating layer is formed between the lower electrode and the upper electrode, and the insulating layer is used for isolating the upper electrode from the lower electrode. The upper electrode and the lower electrode form a capacitor structure, and the piezoelectric layer is used for transmitting and receiving ultrasonic waves; the micro-capacitor structure is electrically connected with the silicon substrate. The micro-capacitor structure has good adaptability to various fingerprint states. The fingerprint identification effect is good.

Description

Technical Field

[0001] The present invention relates to the technical field of fingerprint recognition, and in particular to an ultrasonic fingerprint recognition module. Background Art

[0002] 3D ultrasonic fingerprint recognition sensors are based on the pulse-echo time measurement method of sound waves, and use the characteristics of ultrasound waves that are easy to propagate in human tissues to achieve three-dimensional imaging recognition of fingerprints, improve the security and applicability of mobile payments, and improve user experience. On the one hand, ultrasonic fingerprint sensors can obtain the in-plane relationship between the papilla and furrow of the fingerprint, and can also obtain the relative relationship between the two, and collect three-dimensional details and unique fingerprint feature data that cannot be obtained by current traditional fingerprint technology. At the same time, ultrasound penetrates the epidermis of the finger skin to obtain personal fingerprint subcutaneous biometric information. These unique features can greatly improve information security. On the other hand, ultrasonic fingerprint sensors can penetrate materials such as glass and plastic, and can be placed under the screen or mobile phone shell to complete fingerprint scanning, which provides convenience for mobile phone manufacturers' terminal design. At the same time, fingerprint scanning can be unaffected by possible dirt on the finger, such as sweat, hand cream or condensation, which also improves user experience. However, the efficiency of ultrasonic transmission and reception of traditional ultrasonic sensors is low, and the accuracy and stability are relatively general. Summary of the invention

[0003] The purpose of the present invention is to provide an ultrasonic fingerprint recognition module, aiming to solve the problem of poor fingerprint recognition effect in the prior art.

[0004] The present application provides an ultrasonic fingerprint recognition module, comprising a plurality of ultrasonic fingerprint sensor arrays arranged in an array, wherein the ultrasonic fingerprint sensor array comprises a plurality of ultrasonic fingerprint sensor array elements arranged in an array, and the ultrasonic fingerprint sensor array elements are ultrasonic fingerprint sensors;

[0005] The ultrasonic fingerprint sensor includes a silicon substrate and a micro-capacitor structure arranged on the silicon substrate, the micro-capacitor structure includes a piezoelectric layer, a lower electrode arranged above the piezoelectric layer, and an upper electrode arranged above the lower electrode, an insulating layer is formed between the lower electrode and the upper electrode, the insulating layer is used to isolate the upper electrode from the lower electrode, the upper electrode and the lower electrode form a capacitor structure, the piezoelectric layer is used to transmit and receive ultrasonic waves; the micro-capacitor structure is electrically connected to the silicon substrate.

[0006] Furthermore, a protective substrate is provided above the upper electrode, and the protective substrate is used to protect the micro-capacitor structure. The upper surface of the protective substrate is used to contact the fingerprint of the finger. The micro-capacitor structure is electrically connected to the protective substrate, and the protective substrate is electrically connected to the silicon substrate.

[0007] Furthermore, the insulating layer is made of an insulating material, and the insulating material is silicon dioxide or silicon nitride.

[0008] Furthermore, the upper electrode is made of conductive metal or transparent conductive oxide.

[0009] Furthermore, the piezoelectric layer is made of piezoelectric material, and the piezoelectric material is single crystal ceramic or polycrystalline ceramic.

[0010] Furthermore, the lower electrode is made of conductive metal or transparent conductive oxide.

[0011] Furthermore, a conductive column is provided between the upper surface of the micro-capacitor structure and the lower surface of the protective substrate to achieve electrical connection between the micro-capacitor structure and the protective substrate, and a gap is formed between the micro-capacitor structure and the protective substrate to protect the micro-capacitor structure.

[0012] Furthermore, a conductive support is connected between the lower surface of the protection substrate and the upper surface of the silicon substrate to achieve electrical connection between the protection substrate and the silicon substrate, and a gap exists between the silicon substrate and the micro-capacitor structure.

[0013] Furthermore, the ultrasonic fingerprint sensor array includes ultrasonic fingerprint sensor array elements arranged in a 4×4 array.

[0014] Furthermore, the ultrasonic fingerprint recognition module includes an ultrasonic fingerprint sensor array arranged in a 100×100 array.

[0015] Compared with the prior art, the ultrasonic fingerprint recognition module provided by the present application is provided with a plurality of ultrasonic fingerprint sensor arrays, which are in turn composed of a plurality of ultrasonic fingerprint sensors. The upper electrode is in direct contact with the finger and is used to receive ultrasonic signals. The lower electrode is located below the upper electrode and forms a capacitor structure with the upper electrode. The piezoelectric layer is located below the lower electrode and is used to transmit and receive ultrasonic waves. When the ultrasonic signal acts on the piezoelectric layer, it will produce a slight deformation, thereby causing a change in the capacitance value. When working, the finger presses on the surface of the ultrasonic fingerprint sensor to make the upper electrode contact with the finger. When the ultrasonic signal is emitted to the finger, part of the signal is reflected back and received by the upper electrode. These reflected signals will produce a slight deformation in the piezoelectric layer, thereby changing the capacitance value. By measuring the change in the capacitance value, the fingerprint information of the finger can be obtained. The micro-capacitor structure has good adaptability to various fingerprint states. Whether it is a dry finger, a wet finger, or a finger with slight stains, as long as the finger and the sensor plate can form an effective capacitive coupling, the fingerprint information can be collected. For example, in some humid environments, capacitive fingerprint recognition can still obtain fingerprints more accurately, which is difficult to do with optical fingerprint recognition technology. The fingerprint recognition effect of this application is good. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 is a schematic diagram of the structure of an ultrasonic fingerprint recognition module provided by an embodiment of the present invention;

[0017] Figure 2 Schematic diagram of the structure of an ultrasonic fingerprint sensor provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0018] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be understood as limiting the present invention.

[0019] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0020] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0021] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0022] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being "above", "above" or "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below", "below" or "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0023] The implementation of the present invention is described in detail below in conjunction with specific embodiments.

[0024] Reference Figure 1-2 , an ultrasonic fingerprint recognition module, comprising a plurality of ultrasonic fingerprint sensor arrays arranged in an array, wherein the ultrasonic fingerprint sensor array comprises a plurality of ultrasonic fingerprint sensor array elements arranged in an array, and the ultrasonic fingerprint sensor array elements are ultrasonic fingerprint sensors;

[0025] The ultrasonic fingerprint sensor includes a silicon substrate 5 and a micro-capacitor structure arranged on the silicon substrate 5, the micro-capacitor structure includes a piezoelectric layer 1, a lower electrode 3 arranged above the piezoelectric layer 1, and an upper electrode 2 arranged above the lower electrode 3, an insulating layer 4 is formed between the lower electrode 3 and the upper electrode 2, the insulating layer 4 is used to isolate the upper electrode 2 from the lower electrode 3, the upper electrode 2 and the lower electrode 3 form a capacitor structure, the piezoelectric layer 1 is used to transmit and receive ultrasonic waves; the micro-capacitor structure is electrically connected to the silicon substrate 5.

[0026] Furthermore, a protective substrate 8 is provided above the upper electrode 2, and the protective substrate 8 is used to protect the micro-capacitor structure. The upper surface of the protective substrate 8 is used to contact the fingerprint of the finger. The micro-capacitor structure is electrically connected to the protective substrate 8, and the protective substrate 8 is electrically connected to the silicon substrate 5.

[0027] Furthermore, the insulating layer 4 is made of an insulating material, and the insulating material is silicon dioxide or silicon nitride.

[0028] Furthermore, the upper electrode 2 is made of conductive metal or transparent conductive oxide.

[0029] Furthermore, the piezoelectric layer 1 is made of piezoelectric material, and the piezoelectric material is single crystal ceramic or polycrystalline ceramic.

[0030] Furthermore, the lower electrode 3 is made of conductive metal or transparent conductive oxide.

[0031] Furthermore, a conductive column 6 is provided between the upper surface of the micro-capacitor structure and the lower surface of the protective substrate 8 to achieve electrical connection between the micro-capacitor structure and the protective substrate 8, and a gap is formed between the micro-capacitor structure and the protective substrate 8 to protect the micro-capacitor structure.

[0032] Furthermore, a conductive support member 7 is connected between the lower surface of the protective substrate 8 and the upper surface of the silicon substrate 5 to achieve electrical connection between the protective substrate 8 and the silicon substrate 5, and a gap exists between the silicon substrate 5 and the micro-capacitor structure.

[0033] Furthermore, the ultrasonic fingerprint sensor array includes ultrasonic fingerprint sensor array elements arranged in a 4×4 array.

[0034] Furthermore, the ultrasonic fingerprint recognition module includes an ultrasonic fingerprint sensor array arranged in a 100×100 array.

[0035] The present application provides an ultrasonic fingerprint recognition module, which is provided with a plurality of ultrasonic fingerprint sensor arrays, which are in turn composed of a plurality of ultrasonic fingerprint sensors. The upper electrode is in direct contact with the finger and is used to receive ultrasonic signals. The lower electrode is located below the upper electrode and forms a capacitor structure with the upper electrode. The piezoelectric layer is located below the lower electrode and is used to transmit and receive ultrasonic waves. When the ultrasonic signal acts on the piezoelectric layer, it will produce a slight deformation, thereby causing a change in the capacitance value. When working, the finger presses on the surface of the ultrasonic fingerprint sensor to make the upper electrode contact with the finger. When the ultrasonic signal is emitted to the finger, part of the signal is reflected back and received by the upper electrode. These reflected signals will produce a slight deformation in the piezoelectric layer, thereby changing the capacitance value. By measuring the change in capacitance value, the fingerprint information of the finger can be obtained. The micro-capacitor structure has good adaptability to various fingerprint states. Whether it is a dry finger, a wet finger, or a finger with slight stains, as long as the finger and the sensor plate can form an effective capacitive coupling, the fingerprint information can be collected. For example, in some humid environments, capacitive fingerprint recognition can still obtain fingerprints more accurately, which is difficult for optical fingerprint recognition technology to do. This application has good fingerprint recognition effect.

[0036] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0037] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.

Claims

1. An ultrasonic fingerprint recognition module, characterized in that: An ultrasonic fingerprint sensor array including a plurality of array-arranged ultrasonic fingerprint sensor arrays, wherein the ultrasonic fingerprint sensor array includes a plurality of array-arranged ultrasonic fingerprint sensor array elements, and the ultrasonic fingerprint sensor array elements are ultrasonic fingerprint sensors; The ultrasonic fingerprint sensor includes a silicon substrate and a micro-capacitor structure arranged on the silicon substrate, the micro-capacitor structure includes a piezoelectric layer, a lower electrode arranged above the piezoelectric layer, and an upper electrode arranged above the lower electrode, an insulating layer is formed between the lower electrode and the upper electrode, the insulating layer is used to isolate the upper electrode from the lower electrode, the upper electrode and the lower electrode form a capacitor structure, the piezoelectric layer is used to transmit and receive ultrasonic waves; the micro-capacitor structure is electrically connected to the silicon substrate.

2. The ultrasonic fingerprint recognition module according to claim 1, characterized in that: A protective substrate is also provided above the upper electrode, and is used to protect the micro-capacitor structure. The upper surface of the protective substrate is used to contact the fingerprint of a finger. The micro-capacitor structure is electrically connected to the protective substrate, and the protective substrate is electrically connected to the silicon substrate.

3. The ultrasonic fingerprint recognition module according to claim 1, characterized in that: The insulating layer is made of insulating material, and the insulating material is silicon dioxide or silicon nitride.

4. The ultrasonic fingerprint recognition module according to claim 1, characterized in that: The upper electrode is made of conductive metal or transparent conductive oxide.

5. The ultrasonic fingerprint recognition module according to claim 1, characterized in that: The piezoelectric layer is made of piezoelectric material, and the piezoelectric material is single crystal ceramic or polycrystalline ceramic.

6. The ultrasonic fingerprint recognition module according to claim 1, characterized in that: The lower electrode is made of conductive metal or transparent conductive oxide.

7. The ultrasonic fingerprint recognition module according to claim 2, characterized in that: A conductive column is arranged between the upper surface of the micro-capacitor structure and the lower surface of the protective substrate to achieve electrical connection between the micro-capacitor structure and the protective substrate, and a gap is formed between the micro-capacitor structure and the protective substrate to protect the micro-capacitor structure.

8. The ultrasonic fingerprint recognition module according to claim 7, characterized in that: A conductive support is connected between the lower surface of the protection substrate and the upper surface of the silicon substrate to achieve electrical connection between the protection substrate and the silicon substrate, and a gap exists between the silicon substrate and the micro-capacitor structure.

9. The ultrasonic fingerprint recognition module according to claim 1, characterized in that: The ultrasonic fingerprint sensor array includes ultrasonic fingerprint sensor array elements arranged in a 4×4 array.

10. The ultrasonic fingerprint recognition module according to claim 1, characterized in that: The ultrasonic fingerprint recognition module includes an ultrasonic fingerprint sensor array arranged in a 100×100 array.

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