Fingerprint module and electronic equipment

Abstract

The embodiment of the utility model provides a fingerprint module and electronic equipment. The fingerprint module comprises an ultrasonic sensor and an isolation layer, the ultrasonic sensor is arranged on the first side of the isolating layer; the ultrasonic sensor can emit an ultrasonic signal and receive a first ultrasonic reflection signal reflected by the object to be identified, converts the first ultrasonic reflection signal into an identification signal, and sends the identification signal to the processing unit, so that the processing unit performs fingerprint identification based on the identification signal; the isolation layer can reduce a second ultrasonic reflection signal received by the ultrasonic sensor, the second ultrasonic reflection signal is formed by transmitting an ultrasonic signal through a reflection structure located on the second side of the isolation layer, and the first side of the isolation layer is opposite to the second side of the isolation layer. According to the fingerprint module provided by the embodiment of the invention, the foreign matter image in the identified fingerprint image can be reduced.

Description

Technical Field

[0001] This application relates to the field of fingerprint module technology, and more particularly to a fingerprint module and electronic device. Background Technology

[0002] There are two main publicly disclosed under-display fingerprint recognition solutions: optical fingerprint and ultrasonic fingerprint. The performance of optical fingerprint modules is significantly affected by the screen's light transmittance. With the increasing complexity of internal display wiring and the development of flexible screen solutions, the screen's optical transmittance has decreased, rendering optical fingerprint solutions inadequate for application requirements. Ultrasonic fingerprint solutions, on the other hand, do not depend on the screen's optical transmittance and are a better alternative.

[0003] In existing ultrasonic fingerprint solutions, the fingerprint module is positioned relative to the screen in the electronic device.

[0004] However, the ultrasonic sensor in the fingerprint module receives ultrasonic signals reflected from the finger, as well as ultrasonic signals reflected from the internal structure of the electronic device. This causes the fingerprint image identified based on the ultrasonic signal to include images of foreign objects, thus reducing the fingerprint recognition success rate. Utility Model Content

[0005] In view of this, embodiments of this application provide a fingerprint module and an electronic device to at least partially solve the above-mentioned problems.

[0006] According to a first aspect of the present application, a fingerprint module is provided for use in an electronic device. The fingerprint module includes: an ultrasonic sensor and an isolation layer; the ultrasonic sensor is disposed on a first side of the isolation layer; the ultrasonic sensor is configured to emit an ultrasonic signal and receive a first ultrasonic reflection signal reflected back by an object to be identified, convert the first ultrasonic reflection signal into an identification signal, and send the identification signal to a processing unit so that the processing unit performs fingerprint identification based on the identification signal; the isolation layer is configured to reduce a second ultrasonic reflection signal received by the ultrasonic sensor, the second ultrasonic reflection signal being formed by a reflection structure located on a second side of the isolation layer emitting the ultrasonic signal, the first side and the second side of the isolation layer being opposite to each other.

[0007] In one possible implementation, the ultrasonic sensor includes: a first electrode, an acoustic layer, and a substrate; an electrode array on the substrate forms a second electrode; the acoustic layer is disposed between the first electrode and the second electrode; the acoustic layer is used to emit ultrasonic signals under the drive of the first electrode and the second electrode, and to receive the first ultrasonic reflected signal and convert the first ultrasonic reflected signal into an electrical signal; the substrate is used to convert the electrical signal into the identification signal.

[0008] In one possible implementation, the reflective structure includes: a first adhesive layer and a flexible circuit board; a first surface of the first adhesive layer is bonded to a second side of the isolation layer, a second surface of the first adhesive layer is bonded to the flexible circuit board, the first surface of the first adhesive layer and the second surface of the first adhesive layer are opposite to each other, and the flexible circuit board is electrically connected to the ultrasonic sensor; or, the reflective structure includes: a second adhesive layer and a support plate; a first surface of the second adhesive layer is bonded to a second side of the isolation layer, a second surface of the second adhesive layer is bonded to the support plate, the first surface of the second adhesive layer and the second surface of the second adhesive layer are opposite to each other.

[0009] In one possible implementation, the isolation layer includes: a third adhesive layer and a first reinforcing layer; a first surface of the first reinforcing layer is bonded to the ultrasonic sensor via the third adhesive layer; a second surface of the first reinforcing layer serves as a second side of the isolation layer and is bonded to the first surface of the first adhesive layer or the first surface of the second adhesive layer; the first surface of the first reinforcing layer is opposite to the second surface of the first reinforcing layer; the acoustic impedance of the third adhesive layer is different from that of the ultrasonic sensor, and the acoustic impedance of the third adhesive layer is different from that of the first reinforcing layer.

[0010] In one possible implementation, the acoustic impedance of the third adhesive layer is less than 5 MRayl, and the acoustic impedance of the first reinforcing layer is greater than 10 MRayl.

[0011] In one possible implementation, the thickness of the third adhesive layer is λ1 / 4 or 3λ1 / 4, where λ1 = V1 / f, V1 is used to characterize the transmission speed of the ultrasonic signal in the third adhesive layer, and f is used to characterize the frequency of the ultrasonic signal; and / or, the thickness of the first reinforcing layer is λ2 / 4 or 3λ2 / 4, where λ2 = V2 / f, and V2 is used to characterize the transmission speed of the ultrasonic signal in the first reinforcing layer.

[0012] In one possible implementation, the isolation layer includes a plurality of sub-isolation layers stacked together. Each sub-isolation layer includes a fourth adhesive layer and a second reinforcing layer bonded to a first surface of the fourth adhesive layer. The second surface of the fourth adhesive layer in the first sub-isolation layer is bonded to the ultrasonic sensor, and the first surface of the fourth adhesive layer is opposite to the second surface of the fourth adhesive layer. The second surface of the fourth adhesive layer in the i-th sub-isolation layer is bonded to the second surface of the second reinforcing layer in the (i-1)-th sub-isolation layer, where i is an integer greater than 1 and less than or equal to N, and N is the number of sub-isolation layers. The first surface of the second reinforcing layer is opposite to the second surface of the second reinforcing layer. The second surface of the second reinforcing layer in the N-th sub-isolation layer serves as a second side of the isolation layer and is bonded to the first surface of the first adhesive layer or the first surface of the second adhesive layer.

[0013] In one possible implementation, the acoustic impedance of the fourth adhesive layer is less than 5 MRayl, and the acoustic impedance of the second reinforcing layer is greater than 10 MRayl.

[0014] In one possible implementation, the thickness of the fourth adhesive layer is λ3 / 4 or 3λ3 / 4, where λ3 = V3 / f, V3 is used to characterize the transmission speed of the ultrasonic signal in the fourth adhesive layer, and f is used to characterize the frequency of the ultrasonic signal; and / or, the thickness of the second reinforcing layer is λ4 / 4 or 3λ4 / 4, where λ4 = V4 / f, and V4 is used to characterize the transmission speed of the ultrasonic signal in the second reinforcing layer.

[0015] In one possible implementation, the thickness of the substrate is λ5 / 4 or 3λ5 / 4, where λ5 = V5 / f, V5 is used to characterize the transmission speed of the ultrasonic signal in the substrate, and f is used to characterize the frequency of the ultrasonic signal.

[0016] According to a second aspect of the present application, an electronic device is provided, comprising: a processing unit and a fingerprint module as described in the first aspect, wherein the processing unit is configured to perform fingerprint recognition based on an identification signal transmitted by the fingerprint module.

[0017] According to the fingerprint module provided in the embodiments of this application, the fingerprint module includes an ultrasonic sensor and an isolation layer. The ultrasonic sensor can emit ultrasonic signals and receive a first ultrasonic reflection signal reflected back by the object to be identified. After converting the first ultrasonic reflection signal into an identification signal, the identification signal is sent to the processing unit of the electronic device. The processing unit performs fingerprint identification based on the identification signal, thereby realizing the fingerprint identification function. Compared with the fingerprint module in the prior art, since an isolation layer is provided between the fingerprint module and the reflective structure, the second ultrasonic reflection signal received by the ultrasonic sensor and formed by the reflection of the reflective structure can be reduced. The interference of the reflective structure can be reduced during the fingerprint identification process, so that the fingerprint image generated by the processing unit based on the identification signal is closer to the object to be identified, thereby making the fingerprint identification more accurate and improving the user experience. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings.

[0019] Figure 1 This is a schematic diagram of a fingerprint module provided in an embodiment of this application;

[0020] Figure 2 This is a schematic diagram of an ultrasonic sensor provided in an embodiment of this application;

[0021] Figure 3 This is a schematic diagram of a reflective structure provided in an embodiment of this application;

[0022] Figure 4 This is a schematic diagram of another reflection structure provided in an embodiment of this application;

[0023] Figure 5 This is a schematic diagram of an isolation layer provided in an embodiment of this application;

[0024] Figure 6 This is a schematic diagram of ultrasonic transmittance provided in an embodiment of this application;

[0025] Figure 7 This is a schematic diagram of another ultrasonic transmittance provided in an embodiment of this application;

[0026] Figure 8 This is a schematic diagram of another isolation layer provided in an embodiment of this application;

[0027] Figure 9 This is a schematic diagram of an electronic device provided in an embodiment of this application. Detailed Implementation

[0028] To enable those skilled in the art to better understand the technical solutions in the embodiments of this application, the technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art should fall within the protection scope of the embodiments of this application.

[0029] The terminology used in this application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. The singular forms “a,” “the,” and “the” used in this application and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the term “and / or” as used herein refers to and includes any or all possible combinations of one or more of the associated listed items.

[0030] It should be understood that although the terms first, second, third, etc., may be used in this application to describe various information, such information should not be limited to these terms. These terms are only used to distinguish information of the same type from one another. For example, without departing from the scope of this application, first information may also be referred to as second information, and similarly, second information may also be referred to as first information. Depending on the context, the word "if" as used herein may be interpreted as "when," "when," or "in response to determination."

[0031] As mentioned earlier, there are two main publicly disclosed under-display fingerprint recognition solutions: optical fingerprint and ultrasonic fingerprint. The performance of optical fingerprint modules is significantly affected by the screen's light transmittance. With the increasing complexity of internal wiring in displays and the development of flexible screen solutions, the screen's optical transmittance has decreased, rendering optical fingerprint solutions inadequate for application requirements. Ultrasonic fingerprint solutions, however, do not depend on the screen's optical transmittance and are a better alternative. In existing ultrasonic fingerprint solutions, the fingerprint module is positioned relative to the screen in the electronic device. However, the ultrasonic sensor in the fingerprint module receives ultrasonic signals reflected from the finger, as well as ultrasonic signals reflected from the internal structure of the electronic device. This results in the fingerprint image, based on the ultrasonic signal, including images of foreign objects, reducing the fingerprint recognition success rate.

[0032] This application provides a fingerprint module including an ultrasonic sensor and an isolation layer. The ultrasonic sensor can emit ultrasonic signals and receive a first ultrasonic reflection signal reflected back by the object to be identified. After converting the first ultrasonic reflection signal into an identification signal, the identification signal is sent to the processing unit of the electronic device. The processing unit performs fingerprint identification based on the identification signal, thereby realizing the fingerprint identification function. Compared with the fingerprint modules in the prior art, since an isolation layer is provided between the fingerprint module and the reflective structure, the second ultrasonic reflection signal received by the ultrasonic sensor and formed by the reflection of the reflective structure can be reduced. This reduces the interference of the reflective structure during the fingerprint identification process, making the fingerprint image generated by the processing unit based on the identification signal closer to the object to be identified, thereby making the fingerprint identification more accurate and improving the user experience.

[0033] Figure 1 This is a schematic diagram of a fingerprint module 100 provided in an embodiment of this application. The fingerprint module 100 is applied to electronic devices, such as... Figure 1 As shown, the fingerprint module 100 includes an ultrasonic sensor 101 and an isolation layer 103. The ultrasonic sensor 101 is disposed on the first side of the isolation layer 103. The ultrasonic sensor 101 can emit ultrasonic signals and receive a first ultrasonic reflection signal reflected back by the object to be identified. It converts the first ultrasonic reflection signal into an identification signal and sends the identification signal to the processing unit so that the processing unit can perform fingerprint identification based on the identification signal. The isolation layer 103 can reduce the second ultrasonic reflection signal received by the ultrasonic sensor 101. The second ultrasonic reflection signal is formed by the reflection structure located on the second side of the isolation layer 103 emitting ultrasonic signals. The first side and the second side of the isolation layer 103 are opposite to each other.

[0034] The fingerprint module 100 includes an ultrasonic sensor 101. One side of the ultrasonic sensor 101 is bonded to an electronic device, for example, one side of the ultrasonic sensor 101 is bonded to the display screen of the electronic device, and the other side of the ultrasonic sensor 101 is bonded to the first side of the isolation layer 103. The ultrasonic sensor 101 can emit ultrasonic signals. After the ultrasonic sensor 101 emits ultrasonic signals, at least part of the ultrasonic signals are reflected by the finger to form a first ultrasonic reflection signal. After receiving the first ultrasonic reflection signal, the ultrasonic sensor 101 generates an identification signal based on the first ultrasonic reflection signal and sends the identification signal to the processing unit of the electronic device. The processing unit identifies the fingerprint image based on the identification signal and compares the fingerprint image with the stored fingerprint template to realize the fingerprint recognition process.

[0035] It should be understood that when the ultrasonic sensor 101 emits ultrasonic signals, the ultrasonic signals do not propagate in a single direction. For example, the ultrasonic signals not only propagate to the outside of the electronic device, but also to the inside of the electronic device. Therefore, at least part of the ultrasonic signals are reflected by the reflective structure located on the second side of the isolation layer 103 to form a second ultrasonic reflection signal. For example, the ultrasonic signals are reflected by the device structure, air bubbles in the adhesive layer, etc. to form a second ultrasonic reflection signal. At this time, the ultrasonic sensor 101 will not only receive the first ultrasonic reflection signal reflected back by the finger, but also the second ultrasonic reflection signal. Therefore, the fingerprint image identified based on the first ultrasonic reflection signal will include the foreign object image based on the second ultrasonic reflection signal, which will reduce the fingerprint recognition success rate.

[0036] An isolation layer 103 is disposed between the ultrasonic sensor 101 and the reflective structure. The isolation layer 103 can reduce the second ultrasonic reflection signal. In one example, the isolation layer 103 can block the transmission of the ultrasonic signal from the ultrasonic sensor 101 to the reflective structure and can also block the transmission of the second ultrasonic reflection signal reflected by the reflective structure to the ultrasonic sensor 101. This reduces the second ultrasonic reflection signal, making the signal strength of the second ultrasonic reflection signal received by the ultrasonic sensor 101 lower. As a result, when the ultrasonic sensor 101 generates a fingerprint image based on the first ultrasonic reflection signal, the foreign object image generated based on the second ultrasonic reflection signal is weaker.

[0037] In this embodiment, the fingerprint module 100 includes an ultrasonic sensor 101 and an isolation layer 103. The ultrasonic sensor 101 can emit ultrasonic signals and receive a first ultrasonic reflection signal reflected back by the object to be identified. After converting the first ultrasonic reflection signal into an identification signal, the identification signal is sent to the processing unit of the electronic device. The processing unit performs fingerprint identification based on the identification signal, thereby realizing the fingerprint identification function. Compared with the fingerprint module 100 in the prior art, since an isolation layer 103 is provided between the fingerprint module 100 and the reflective structure, the second ultrasonic reflection signal received by the ultrasonic sensor 101 and formed by the reflection of the reflective structure can be reduced. This can reduce the interference of the reflective structure during the fingerprint identification process, making the fingerprint image generated by the processing unit based on the identification signal closer to the object to be identified, thereby making the fingerprint identification more accurate and improving the user experience.

[0038] Figure 2 This is a schematic diagram of an ultrasonic sensor provided in an embodiment of this application, as shown below. Figure 2As shown, the ultrasonic sensor 101 includes: a first electrode 1011, an acoustic layer 1012, and a substrate 1013. An electrode array on the substrate 1013 forms a second electrode 1014. The acoustic layer 1012 is disposed between the first electrode 1011 and the second electrode 1014. The acoustic layer 1012 is used to emit ultrasonic signals under the drive of the first electrode 1011 and the second electrode 1014, and to receive a first ultrasonic reflected signal and convert the first ultrasonic reflected signal into an electrical signal. The substrate 1013 is used to convert the electrical signal into an identification signal.

[0039] The ultrasonic sensor 101 includes a first electrode 1011, an acoustic layer 1012, and a substrate 1013. The substrate 1013 includes multiple complementary metal-oxide-semiconductor (CMOS) sensors. At least some of the CMOS sensors are arranged in a matrix to form a second electrode 1014. A voltage difference can be formed between the second electrode 1014 and the first electrode 1011, thereby powering the acoustic layer 1012. During fingerprint recognition, each CMOS sensor is equivalent to a "pixel". After the acoustic layer 1012 receives the first ultrasonic wave reflected back by the object to be recognized (e.g., a finger), the voltage signal converted on each CMOS sensor will be different depending on the intensity of the first ultrasonic wave reflected signal. The voltage signal of each CMOS sensor is calculated by an algorithm to generate a recognition signal and send it to the processing unit. The processing unit outputs a fingerprint image based on the recognition signal for fingerprint recognition.

[0040] Optionally, the first electrode 1011 can be grounded through an electrical connection area on the substrate 1013, thereby the first electrode 1011 can be grounded as a cathode layer, and the second electrode 1014 can be grounded as an anode layer. When receiving external pressure (e.g., when pressed by a finger during fingerprint recognition), a voltage difference can be formed between the second electrode 1014 and the first electrode 1011, which can then supply power to the acoustic layer 1012 to provide the voltage required for the acoustic layer 1012 to transmit and receive ultrasonic signals.

[0041] In one example, the acoustic layer 1012 in this application may include a piezoelectric material. A voltage can be applied to the piezoelectric material of the acoustic layer 1012 via the first electrode 1011 and the second electrode 1014. Based on the piezoelectric effect of the piezoelectric material, the acoustic layer 1012 can emit ultrasonic signals and receive first ultrasonic reflected signals reflected back from the object to be identified. Optionally, the piezoelectric material of the acoustic layer 1012 can be a film layer, which can be formed using a coating process. This application does not limit the piezoelectric material; for example, the piezoelectric material can be polyvinylidene fluoride (PVDF), including but not limited to PVDF and its copolymers. Therefore, the acoustic layer 1012 in this application includes a PVDF material layer, which can effectively meet the requirements of emitting ultrasonic signals and receiving ultrasonic signals reflected back from external structures.

[0042] In this embodiment, the ultrasonic sensor 101 includes a first electrode 1011, an acoustic layer 1012, and a substrate 1013. The acoustic layer 1012 can be powered by the substrate 1013 and the first electrode 1011, so that the acoustic layer 1012 emits ultrasonic signals and receives first ultrasonic reflection signals. The substrate 1013 can generate an identification signal based on the first ultrasonic reflection signal, thereby realizing fingerprint identification by emitting ultrasonic signals and performing fingerprint identification based on the first ultrasonic reflection signal formed by the reflection of the object to be identified.

[0043] Figure 3 This is a schematic diagram of a reflective structure provided in an embodiment of this application, such as... Figure 3 As shown, the reflective structure includes: a first adhesive layer 201 and a flexible circuit board 102. The first surface of the first adhesive layer 201 is bonded to the second side of the insulating layer 103, and the second surface of the first adhesive layer 201 is bonded to the flexible circuit board 102. The first surface and the second surface of the first adhesive layer 201 are opposite to each other. The flexible circuit board 102 is electrically connected to the ultrasonic sensor 101, or... Figure 4 This is a schematic diagram of another reflection structure provided in an embodiment of this application, such as... Figure 4 As shown, the reflective structure includes a second adhesive layer 202 and a support plate 104. The first surface of the second adhesive layer 202 is bonded to the second side of the isolation layer 103, and the second surface of the second adhesive layer 202 is bonded to the support plate 104. The first surface of the second adhesive layer 202 is opposite to the second surface of the second adhesive layer 202.

[0044] like Figure 3As shown, the reflective structure can be a first adhesive layer 201 and a flexible circuit board 102. The flexible circuit board 102 is bonded to the second side of the isolation layer 103 through the first adhesive layer 201. The flexible circuit board 102 can serve as a support structure for the ultrasonic sensor 101. At this time, due to the presence of wiring in the flexible circuit board 102, there is an air gap between the flexible circuit board 102 and the first adhesive layer 201. Furthermore, due to manufacturing processes, there are air bubbles and small particles in the first adhesive layer 201, such as air bubbles or sand contained in the first adhesive layer 201. When the ultrasonic signal is transmitted to the reflective structure, due to the presence of air bubbles and small particles in the first adhesive layer 201 and the air gap between the flexible circuit board 102 and the first adhesive layer 201, the signal will be diffracted by the air gap or the air bubbles and small particles in the first adhesive layer 201 to form a second ultrasonic reflection signal. It should be noted that the flexible circuit board 102 can be electrically connected to the ultrasonic sensor 101 and the processing unit in the electronic device, respectively. After the ultrasonic sensor 101 generates an identification signal, it can send the identification signal to the processing unit through the flexible circuit board 102.

[0045] like Figure 4 As shown, the reflective structure can also be a second adhesive layer 202 and a support plate 104. The support plate 104 is bonded to the second side of the isolation layer 103 through the second adhesive layer 202. The support plate 104 can serve as a support structure for the ultrasonic sensor 101. The support plate 104 can be made of metal such as steel plate or plastic. Due to process reasons, there may be air bubbles and small particles in the second adhesive layer 202, or the surface of the support plate 104 may be uneven, resulting in an air gap between the support plate 104 and the second adhesive layer 202. Similar to the above principle, a second ultrasonic reflection signal will be formed.

[0046] The isolation layer 103 can block the transmission of ultrasonic signals to the reflective structure and can also block the transmission of the second ultrasonic reflected signal formed by the reflective structure to the ultrasonic sensor 101. This can reduce the second ultrasonic reflected signal received by the ultrasonic sensor 101, and can reduce the second ultrasonic reflected signal while supporting the ultrasonic sensor 101 through the reflective structure.

[0047] In this embodiment, the reflective structure includes a first adhesive layer 201 and a flexible circuit board 102, or the reflective structure includes a second adhesive layer 202 and a support plate 104. Thus, the ultrasonic sensor 101 can be supported by the reflective structure. Since an isolation layer 103 is included between the ultrasonic sensor 101 and the reflective structure, the second ultrasonic reflection signal generated by the ultrasonic signal reflected by the reflective structure and received by the ultrasonic sensor 101 can be reduced. This can reduce the impact of the second ultrasonic reflection signal during fingerprint recognition, improve the quality of the recognized fingerprint image, and increase the fingerprint recognition success rate.

[0048] Figure 5 This is a schematic diagram of an isolation layer provided in an embodiment of this application, such as... Figure 5 As shown, the isolation layer 103 includes a third adhesive layer 1031 and a first reinforcing layer 1032. The first surface of the first reinforcing layer 1032 is bonded to the ultrasonic sensor 101 through the third adhesive layer 1031. The second surface of the first reinforcing layer 1032 serves as the second side of the isolation layer 103 and is bonded to the first surface of the first adhesive layer 201 or the first surface of the second adhesive layer 202. The first surface of the first reinforcing layer 1032 is opposite to the second surface of the first reinforcing layer 1032. The acoustic impedance of the third adhesive layer 1031 is different from that of the ultrasonic sensor 101, and the acoustic impedance of the third adhesive layer 1031 is different from that of the first reinforcing layer 1032.

[0049] The isolation layer 103 includes a third adhesive layer 1031 and a first reinforcing layer 1032. The third adhesive layer 1031 and the ultrasonic sensor 101 have different acoustic impedances. Specifically, the substrate of the ultrasonic sensor 101 is made of silicon, and the third adhesive layer 1031 is made of glue, adhesive layer, etc. The acoustic impedance of the third adhesive layer 1031 is different from that of the substrate of the ultrasonic sensor 101. It should be understood that during the transmission of ultrasonic signals, when the ultrasonic signal is incident from material 1 to material 2, it will be reflected. The greater the difference in acoustic impedance between the two materials, the greater the reflectivity and the smaller the corresponding transmittance. Since the acoustic impedance of the third adhesive layer 1031 and the ultrasonic sensor 101 are different, when the ultrasonic signal emitted by the ultrasonic sensor 101 is transmitted to the third adhesive layer 1031, the reflectivity is large and the transmittance is small, which can block the ultrasonic signal from being transmitted to the second side of the isolation layer 103.

[0050] Similarly, after the ultrasonic signal is transmitted through the third adhesive layer 1031, since the acoustic impedance of the third adhesive layer 1031 is different from that of the first reinforcing layer 1032, when the ultrasonic signal emitted by the ultrasonic sensor 101 is transmitted to the first reinforcing layer 1032, the reflectivity is large and the transmittance is small. This can block the ultrasonic signal from being transmitted to the second side of the isolation layer 103 again, thus playing the function of weakening the ultrasonic signal for the second time.

[0051] Conversely, when a portion of the ultrasonic signal is transmitted through the first reinforcing layer 1032, it is reflected or diffracted by the reflective structure to form a second ultrasonic reflected signal. The second ultrasonic reflected signal is transmitted to the ultrasonic sensor 101. Similar to the transmission process described above, since the acoustic impedance of the third adhesive layer 1031 is different from that of the first reinforcing layer 1032, and the acoustic impedance of the third adhesive layer 1031 is different from that of the ultrasonic sensor 101, it can block the ultrasonic signal from being transmitted to the first side of the isolation layer 103, thereby weakening the second ultrasonic reflected signal.

[0052] In this embodiment, the isolation layer 103 includes a third adhesive layer 1031 and a first reinforcing layer 1032. The first surface of the first reinforcing layer 1032 is bonded to the ultrasonic sensor 101 through the third adhesive layer 1031, and the second surface of the first reinforcing layer 1032 is bonded to the reflective structure. The reflective structure can support the isolation layer 103 and the ultrasonic sensor 101. Since the acoustic impedance of the third adhesive layer 1031 is different from that of the ultrasonic sensor 101, and the acoustic impedance of the third adhesive layer 1031 is different from that of the first reinforcing layer 1032, the reflectivity of the ultrasonic signal or the second ultrasonic reflected signal can be increased, the transmittance of the ultrasonic signal or the second ultrasonic reflected signal can be reduced, the transmission of the ultrasonic signal to the reflective structure can be weakened, and the transmission of the second ultrasonic reflected signal to the ultrasonic sensor 101 can be weakened, thereby reducing the second ultrasonic reflected signal received by the ultrasonic sensor 101.

[0053] In one possible implementation, the acoustic impedance of the third adhesive layer 1031 is less than 5 MRayl, and the acoustic impedance of the first reinforcing layer 1032 is greater than 10 MRayl.

[0054] The third adhesive layer 1031 can be a low acoustic impedance material such as glue, and the first reinforcing layer 1032 can be a high acoustic impedance material such as metal or ceramic. It should be understood that, as in the above embodiments, the greater the difference between the acoustic impedance of the third adhesive layer 1031 and the acoustic impedance of the first reinforcing layer 1032, the higher the reflectivity and the lower the transmittance of the ultrasonic signal. Therefore, materials with a large difference between the acoustic impedance of the first reinforcing layer 1032 and the acoustic impedance of the third adhesive layer 1031 are preferred.

[0055] Figure 6 This is a schematic diagram of ultrasonic transmittance provided in an embodiment of this application, as shown below. Figure 6 As shown, Figure 6 The vertical axis represents the transmittance of the ultrasonic signal. When the acoustic impedance of the third adhesive layer 1031 is fixed, and other conditions remain unchanged, such as the thickness of the third adhesive layer 1031 and the thickness of the first reinforcing layer 1032 remaining constant, the transmittance of the ultrasonic signal varies depending on the material used in the first reinforcing layer 1032. For example, the acoustic impedance of the first reinforcing layer 1032 made of silicon is 20 Mrayl, that of the first reinforcing layer 1032 made of aluminum is 17 Mrayl, that of the first reinforcing layer 1032 made of titanium alloy is 28 Mrayl, and that of the first reinforcing layer 1032 made of stainless steel is 45 Mrayl. Figure 6 It can be seen that when the acoustic impedance of the third adhesive layer 1031 is fixed, the greater the acoustic impedance of the first reinforcing layer 1032, the lower the transmittance of the ultrasonic signal. That is, the greater the difference between the acoustic impedance of the third adhesive layer 1031 and the acoustic impedance of the first reinforcing layer 1032, the higher the reflectivity of the ultrasonic signal and the lower the transmittance.

[0056] In this embodiment, the acoustic impedance of the third adhesive layer 1031 is less than 5 MRayl, and the acoustic impedance of the first reinforcing layer 1032 is greater than 10 MRayl. This allows for a larger difference between the acoustic impedance of the third adhesive layer 1031 and the acoustic impedance of the first reinforcing layer 1032, resulting in higher reflectivity and lower transmittance of the ultrasonic signal. This reduces the transmission of the ultrasonic signal to the reflective structure and also reduces the transmission of the second ultrasonic reflected signal to the ultrasonic sensor 101, thereby reducing the second ultrasonic reflected signal received by the ultrasonic sensor 101.

[0057] In one possible implementation, the thickness of the third adhesive layer 1031 is λ1 / 4 or 3λ1 / 4, where λ1 = V1 / f, V1 is used to characterize the transmission speed of the ultrasonic signal in the third adhesive layer 1031, f is used to characterize the frequency of the ultrasonic signal, and / or, the thickness of the first reinforcing layer 1032 is λ2 / 4 or 3λ2 / 4, where f2 = V2 / f, V2 is used to characterize the transmission speed of the ultrasonic signal in the first reinforcing layer 1032.

[0058] λ1 is the wavelength of the ultrasonic signal in the third adhesive layer 1031, and λ2 is the wavelength of the ultrasonic signal in the first reinforcing layer 1032.

[0059] The following explanation uses the third adhesive layer 1031 as an example. The substrate of the ultrasonic sensor 101 is made of silicon. The stack of ultrasonic sensor 101-third adhesive layer 1031-first reinforcing layer 1032 is silicon-adhesive-first reinforcing layer 1032. Figure 7 This is a schematic diagram of another ultrasonic transmittance provided in an embodiment of this application, as shown below. Figure 7 As shown, Figure 7 The horizontal axis in the figure represents the thickness of the third adhesive layer 1031. Figure 7 The vertical axis represents the transmittance of the ultrasonic signal. It should be understood that when the third adhesive layer 1031 is glue, the transmission speed of the ultrasonic signal within it is generally 2.5 km / s. Taking an ultrasonic signal frequency f of 12.5 MHz as an example, λ1 equals 200 μm. Figure 7As shown, for different materials of the first reinforcing layer 1032, when the thickness of the third adhesive layer 1031 is λ1 / 4 or 3λ1 / 4, that is, when the thickness of the third adhesive layer 1031 is 50um and 150um, the probability of ultrasonic signals passing through the third adhesive layer 1031 is the lowest. That is, when the thickness of the third adhesive layer 1031 is an odd multiple of one-quarter of the wavelength of the ultrasonic signal within the third adhesive layer 1031, the transmittance of the ultrasonic signal is low. Among them, the acoustic impedance of the first reinforcing layer 1032 made of silicon is 20Mrayl, the acoustic impedance of the first reinforcing layer 1032 made of aluminum is 17Mrayl, the acoustic impedance of the first reinforcing layer 1032 made of titanium alloy is 28Mrayl, and the acoustic impedance of the first reinforcing layer 1032 made of stainless steel is 45Mrayl.

[0060] Similar to the principle of the third adhesive layer 1031 described above, the first reinforcing layer 1032 has a different acoustic impedance than the third adhesive layer 1031. The first reinforcing layer 1032 serves as the ultrasonic transmission medium. The transmittance of the first reinforcing layer 1032 is lowest when its thickness is λ² / 4 or 3λ² / 4, meaning the thickness of the first reinforcing layer 1032 is an odd multiple of one-quarter of the wavelength of the ultrasonic signal within the first reinforcing layer 1032. In one example, the thickness of the third adhesive layer 1031 is λ¹ / 4 or 3λ¹ / 4, and the thickness of the first reinforcing layer 1032 is also λ² / 4 or 3λ² / 4, thus resulting in a lower transmittance of the ultrasonic signal. It should be noted that the transmission speed of the ultrasonic signal varies in different materials, but the ultrasonic frequency does not change; therefore, λ¹ is generally not equal to λ².

[0061] In this embodiment, the thickness of the third adhesive layer 1031 is an odd multiple of one-quarter of the wavelength of the ultrasonic signal within the third adhesive layer 1031, and / or the thickness of the first reinforcing layer 1032 is an odd multiple of one-quarter of the wavelength of the ultrasonic signal within the first reinforcing layer 1032. This can reduce the transmittance of the ultrasonic signal within the third adhesive layer 1031 and / or the first reinforcing layer 1032, thereby reducing the second ultrasonic reflection signal received by the ultrasonic sensor 101.

[0062] Figure 8 This is a schematic diagram of another isolation layer provided in an embodiment of this application, such as... Figure 8As shown, the isolation layer 103 includes multiple sub-isolation layers stacked together. Each sub-isolation layer includes a fourth adhesive layer 1033 and a second reinforcing layer 1034 bonded to the first surface of the fourth adhesive layer 1033. The second surface of the fourth adhesive layer 1033 in the first sub-isolation layer is bonded to the ultrasonic sensor 101. The first surface of the fourth adhesive layer 1033 is opposite to the second surface of the fourth adhesive layer 1033. The second surface of the fourth adhesive layer 1033 in the i-th sub-isolation layer is bonded to the second surface of the second reinforcing layer 1034 in the (i-1)-th sub-isolation layer. i is an integer greater than 1 and less than or equal to N, where N is the number of sub-isolation layers. The first surface of the second reinforcing layer 1034 is opposite to the second surface of the second reinforcing layer 1034. The second surface of the second reinforcing layer 1034 in the N-th sub-isolation layer serves as the second side of the isolation layer 103 and is bonded to the first surface of the first adhesive layer or the first surface of the second adhesive layer.

[0063] The isolation layer 103 includes at least two sub-isolation layers stacked together, forming a stacked structure of an ultrasonic sensor 101, a first sub-isolation layer, a second sub-isolation layer, a third sub-isolation layer... an Nth sub-isolation layer and a reflective structure. Each sub-isolation layer includes a fourth adhesive layer 1033 and a second reinforcing layer 1034. The second reinforcing layer 1034 of the first sub-isolation layer is bonded to the ultrasonic sensor 101 through the fourth adhesive layer 1033 in the first sub-isolation layer. The second reinforcing layers 1034 in the second to Nth sub-isolation layers are bonded to the second reinforcing layer 1034 in the previous sub-isolation layer through the fourth adhesive layer 1033 in the corresponding sub-isolation layer. The second reinforcing layer 1034 in the Nth sub-isolation layer is bonded to the reflective structure.

[0064] It should be noted that the fourth adhesive layer 1033 and the second reinforcing layer 1034 included in each sub-isolation layer are similar in principle to the third adhesive layer 1031 and the first reinforcing layer 1032 in the above embodiments. For details, please refer to the description of the third adhesive layer 1031 and the first reinforcing layer 1032 in the above embodiments, which will not be repeated here.

[0065] In this embodiment, the isolation layer 103 includes multiple sub-isolation layers stacked together. This allows the transmittance of the ultrasonic signal to be reduced through the multiple sub-isolation layers. Compared with the above embodiment where the isolation layer 103 only includes the third adhesive layer 1031 and the first reinforcing layer 1032, the multiple sub-isolation layers can further reduce the transmittance of the ultrasonic signal and the second ultrasonic reflection signal in the isolation layer 103, thereby reducing the second ultrasonic reflection signal received by the ultrasonic sensor 101.

[0066] In one possible implementation, the acoustic impedance of the fourth adhesive layer 1033 is less than 5 MRayl, and the acoustic impedance of the second reinforcing layer 1034 is greater than 10 MRayl.

[0067] In this embodiment, the acoustic impedance of the fourth adhesive layer 1033 is less than 5 MRayl, and the acoustic impedance of the second reinforcing layer 1034 is greater than 10 MRayl. This allows for a large difference between the acoustic impedance of the fourth adhesive layer 1033 and the acoustic impedance of the second reinforcing layer 1034, resulting in a higher reflectivity and lower transmittance of the ultrasonic signal. This reduces the transmission of the ultrasonic signal to the reflective structure and the transmission of the second ultrasonic reflected signal to the ultrasonic sensor 101, thereby reducing the second ultrasonic reflected signal received by the ultrasonic sensor 101.

[0068] In one possible implementation, the thickness of the fourth adhesive layer 1033 is λ3 / 4 or 3λ3 / 4, where λ3 = V3 / f, V3 is used to characterize the transmission speed of the ultrasonic signal in the fourth adhesive layer 1033, f is used to characterize the frequency of the ultrasonic signal, and / or, the thickness of the second reinforcing layer 1034 is λ4 / 4 or 3λ4 / 4, where λ4 = V4 / f, V4 is used to characterize the transmission speed of the ultrasonic signal in the second reinforcing layer 1034.

[0069] In this embodiment, the thickness of the fourth adhesive layer 1033 is an odd multiple of one-quarter of the wavelength of the ultrasonic signal within the fourth adhesive layer 1033, and / or the thickness of the second reinforcing layer 1034 is an odd multiple of one-quarter of the wavelength of the ultrasonic signal within the second reinforcing layer 1034. This can reduce the transmittance of the ultrasonic signal within the fourth adhesive layer 1033 and / or the second reinforcing layer 1034, thereby reducing the second ultrasonic reflection signal received by the ultrasonic sensor 101.

[0070] It should be noted that the fourth adhesive layer 1033 and the second reinforcing layer 1034 provided in this application embodiment are similar to the third adhesive layer 1031 and the first reinforcing layer 1032 in the above embodiment. When the thickness of the fourth adhesive layer 1033 and the second reinforcing layer 1034 is an odd multiple of one-quarter of the wavelength of the ultrasonic signal transmission, the transmittance of the ultrasonic signal in the fourth adhesive layer 1033 and the second reinforcing layer 1034 is low. For the specific principle, please refer to the description of the third adhesive layer 1031 and the first reinforcing layer 1032 in the above embodiment, which will not be repeated here.

[0071] In one possible implementation, the thickness of the substrate 1013 is λ5 / 4 or 3λ5 / 4, where λ5 = V5 / f, V5 is used to characterize the transmission speed of the ultrasonic signal in the substrate 1013, and f is used to characterize the frequency of the ultrasonic signal.

[0072] The substrate 1013 is a silicon substrate 1013. Similar to the principle described in the above embodiments, when the thickness of the substrate 1013 is an odd multiple of one-quarter of the wavelength of the ultrasonic signal when it is transmitted in the substrate 1013, the transmittance of the ultrasonic signal in the substrate 1013 is low. For the specific principle, please refer to the description in the above embodiments, which will not be repeated here.

[0073] In this embodiment, the thickness of the substrate 1013 in the ultrasonic sensor 101 is an odd multiple of one-quarter of the wavelength of the ultrasonic signal transmitted within the substrate 1013. This reduces the transmittance of the ultrasonic signal within the substrate 1013, thereby decreasing the transmittance of the ultrasonic signal and the second ultrasonic reflected signal within the substrate 1013 and thus reducing the second ultrasonic reflected signal received by the ultrasonic sensor 101.

[0074] Figure 9 This is a schematic diagram of an electronic device provided in an embodiment of this application, such as... Figure 9 As shown, the electronic device 300 includes a processing unit 301 and a fingerprint module 100 in any of the above embodiments. The processing unit 301 can perform fingerprint recognition based on the recognition signal transmitted by the fingerprint module 100.

[0075] In this embodiment, the processing unit 301 of the electronic device 300 can perform fingerprint recognition based on the recognition signal transmitted by the fingerprint module 100. Since the fingerprint module 100 includes an isolation layer 103, the intensity of the second ultrasonic wave reflection signal reflected back by the reflection structure received by the fingerprint module 100 is low. Therefore, the proportion of the recognition signal converted from the first ultrasonic wave reflection signal reflected back by the object to be recognized is high. The fingerprint image recognized by the processing unit 301 based on the recognition signal contains fewer foreign object images formed by the second ultrasonic wave reflection signal, which can improve the accuracy of the fingerprint image, thereby improving the accuracy of fingerprint recognition for the user and enhancing the user's fingerprint recognition experience.

[0076] It should be noted that, depending on the implementation needs, the various components / steps described in the embodiments of this application can be broken down into more components / steps, or two or more components / steps or parts of the operation of components / steps can be combined into new components / steps to achieve the purpose of the embodiments of this application.

[0077] Those skilled in the art will recognize that the units and method steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of the embodiments of this application.

[0078] The above embodiments are only used to illustrate the embodiments of this application, and are not intended to limit the embodiments of this application. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of the embodiments of this application. Therefore, all equivalent technical solutions also fall within the scope of the embodiments of this application, and the patent protection scope of the embodiments of this application should be defined by the claims.

Claims

1. A fingerprint module applied to an electronic device, characterized in that, The fingerprint module comprises: an ultrasonic sensor and an isolation layer; The ultrasonic sensor is arranged on a first side of the isolation layer; The ultrasonic sensor is configured to emit an ultrasonic signal, receive a first ultrasonic reflection signal reflected by a to-be-identified object, convert the first ultrasonic reflection signal into an identification signal, and send the identification signal to a processing unit of the electronic device, so that the processing unit performs fingerprint identification based on the identification signal. The isolation layer is configured to reduce a second ultrasonic reflection signal received by the ultrasonic sensor, the second ultrasonic reflection signal being formed by the ultrasonic sensor emitting the ultrasonic signal and being reflected by a reflection structure on a second side of the isolation layer, the first side of the isolation layer and the second side of the isolation layer being opposite.

2. The fingerprint module of claim 1, wherein, The ultrasonic sensor comprises: a first electrode, an acoustic layer, and a substrate; An electrode array on the substrate forms a second electrode, the acoustic layer is arranged between the first electrode and the second electrode, the acoustic layer is configured to emit an ultrasonic signal under the driving of the first electrode and the second electrode, receive the first ultrasonic reflection signal, and convert the first ultrasonic reflection signal into an electrical signal, and the substrate is configured to convert the electrical signal into the identification signal.

3. The fingerprint module of claim 1, wherein, The reflection structure comprises: a first adhesive layer and a flexible circuit board; A first surface of the first adhesive layer is bonded to the second side of the isolation layer, a second surface of the first adhesive layer is bonded to the flexible circuit board, the first surface of the first adhesive layer is opposite to the second surface of the first adhesive layer, and the flexible circuit board is electrically connected to the ultrasonic sensor; Alternatively, the reflection structure comprises: a second adhesive layer and a support plate; A first surface of the second adhesive layer is bonded to the second side of the isolation layer, a second surface of the second adhesive layer is bonded to the support plate, and the first surface of the second adhesive layer is opposite to the second surface of the second adhesive layer.

4. The fingerprint module of claim 3, wherein, The isolation layer comprises: a third adhesive layer and a first reinforcing layer; A first surface of the first reinforcing layer is bonded to the ultrasonic sensor through the third adhesive layer, a second surface of the first reinforcing layer is bonded to the first surface of the first adhesive layer or the first surface of the second adhesive layer as the second side of the isolation layer, the first surface of the first reinforcing layer is opposite to the second surface of the first reinforcing layer, the acoustic impedance of the third adhesive layer is different from that of the ultrasonic sensor, and the acoustic impedance of the third adhesive layer is different from that of the first reinforcing layer.

5. The fingerprint module of claim 4, wherein, The acoustic impedance of the third adhesive layer is less than 5 MRayl, and the acoustic impedance of the first reinforcing layer is greater than 10 MRayl.

6. The fingerprint module of claim 4, wherein, The thickness of the third adhesive layer is λ1 / 4 or 3λ1 / 4, where λ1=V1 / f, V1 is used to represent the transmission speed of the ultrasonic signal in the third adhesive layer, and f is used to represent the frequency of the ultrasonic signal; And / or, the thickness of the first reinforcing layer is λ2 / 4 or 3λ2 / 4, where λ2=V2 / f, V2 is used to represent the transmission speed of the ultrasonic signal in the first reinforcing layer.

7. The fingerprint module of claim 3, wherein the light source is a light emitting diode. The isolation layer comprises a plurality of sub-isolation layers arranged in a stack, the sub-isolation layers comprising a fourth adhesive layer and a second reinforcing layer bonded to a first surface of the fourth adhesive layer; A second surface of the fourth adhesive layer comprised by a first sub-isolation layer of the plurality of sub-isolation layers is bonded to the ultrasonic sensor, the first surface of the fourth adhesive layer being opposite to the second surface of the fourth adhesive layer; A second surface of the fourth adhesive layer comprised by an i-th sub-isolation layer of the plurality of sub-isolation layers is bonded to a second surface of the second reinforcing layer comprised by an (i-1)-th sub-isolation layer, i being an integer greater than 1 and less than or equal to N, N being the number of the sub-isolation layers, the first surface of the second reinforcing layer being opposite to the second surface of the second reinforcing layer; A second surface of the second reinforcing layer comprised by an N-th sub-isolation layer of the plurality of sub-isolation layers is bonded to the first surface of the first adhesive layer or the first surface of the second adhesive layer as a second side of the isolation layer.

8. The fingerprint module of claim 7, wherein, An acoustic impedance of the fourth adhesive layer is less than 5 MRayl, and an acoustic impedance of the second reinforcing layer is greater than 10 MRayl.

9. The fingerprint module of claim 7, wherein, A thickness of the fourth adhesive layer is λ3 / 4 or 3λ3 / 4, where λ3 = V3 / f, V3 being used to represent a transmission speed of the ultrasonic signal in the fourth adhesive layer, and f being used to represent a frequency of the ultrasonic signal. And / or, a thickness of the second reinforcing layer is λ4 / 4 or 3λ4 / 4, where λ4 = V4 / f, V4 being used to represent a transmission speed of the ultrasonic signal in the second reinforcing layer.

10. The fingerprint module of claim 2, wherein, A thickness of the substrate is λ5 / 4 or 3λ5 / 4, where λ5 = V5 / f, V5 being used to represent a transmission speed of the ultrasonic signal in the substrate, and f being used to represent a frequency of the ultrasonic signal.

11. An electronic device, comprising: Comprise: a processing unit and a fingerprint module as claimed in any one of claims 1-10; the processing unit is configured to perform fingerprint identification according to an identification signal transmitted by the fingerprint module.

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