CN115641618B - Fingerprint sensor and electronic equipment - Google Patents

Abstract

The embodiment of the application provides a fingerprint sensor and electronic equipment. The fingerprint sensor comprises a light emitting component, a magnetic film, a magneto-optical medium layer, an analyzer and an image sensor. The light exit assembly is configured to emit linearly polarized light. The magnetic film is arranged on one side of the light emitting component. The surface of the magnetic film facing away from the light emitting component is a fingerprint receiving area. The magneto-optical medium layer is arranged on the other side of the light emitting component. The magnetic thin film is arranged opposite to the magneto-optical medium layer. The magneto-optical medium layer is located in the magnetic field generated by the magnetic film. The magneto-optical medium layer is configured to receive linearly polarized light and rotate the linearly polarized light. The analyzer is arranged on one side of the magneto-optical medium layer, which is opposite to the light emitting component. The analyzer has a first polarization direction that allows light to pass therethrough. The vibration direction of the linearly polarized light intersects the first polarization direction. The image sensor is arranged on one side of the analyzer, which is away from the magneto-optical medium layer. The image sensor is configured to receive the linearly polarized light exiting the analyzer. The fingerprint sensor can effectively improve fingerprint identification accuracy.

Description

Fingerprint sensors and electronic devices

Technical field

Embodiments of the present application relate to the field of terminal technology, and in particular to a fingerprint sensor and electronic equipment.

Background technique

With the explosive growth of electronic devices such as smartphones or tablet computers (PADs), electronic devices have more and more functions. As users become more aware of information data security, more and more electronic devices have added different encryption methods. For example, the distal pads of human fingers have fingerprints formed by uneven skin. Each person's fingerprint pattern is different in patterns, breakpoints and intersections, making the fingerprint unique and stable. Since the fingerprint characteristics of the human body are unique and stable, with the development of technology, more and more electronic devices use fingerprint recognition technology to unlock or encrypt electronic devices, thereby effectively improving the security of electronic devices during use. Security of Personal Information.

Currently, the fingerprint recognition technology used in electronic devices is optical fingerprint recognition technology. When performing related operations through fingerprints, the finger is placed on the fingerprint contact area, and a fingerprint image is formed on the image sensor through the refraction and reflection of light. The acquired fingerprint image is compared with the fingerprint image recorded for the first time in the electronic device, and finally the identification judgment is made. However, when the user's fingers are in a wet state, the user's fingers cannot be recognized by the optical fingerprint recognition system, causing the optical fingerprint recognition to fail and affecting the convenience and experience of using the electronic device.

Contents of the invention

Embodiments of the present application provide a fingerprint sensor and an electronic device, which can effectively improve the recognition accuracy of the fingerprint sensor, reduce the possibility of fingerprint recognition failure, and improve the convenience and experience of using the electronic device.

A first aspect of this application provides a fingerprint sensor, which at least includes a light emitting component, a magnetic film, a magneto-optical medium layer, a polarizer and an image sensor. The light emitting component is configured to emit linearly polarized light. The magnetic film is arranged on one side of the light emitting component. The surface of the magnetic film facing away from the light emitting component is the fingerprint receiving area. The magneto-optical medium layer is disposed on the other side of the light emitting component. The magnetic film is arranged opposite to the magneto-optical medium layer. The magneto-optical medium layer is located in the magnetic field generated by the magnetic film. The magneto-optical medium layer is configured to receive linearly polarized light and rotate the linearly polarized light. The analyzer is disposed on the side of the magneto-optical medium layer facing away from the light emitting component. The analyzer has a first polarization direction that allows light to pass through. The vibration direction of linearly polarized light intersects the first polarization direction. The image sensor is arranged on the side of the analyzer facing away from the magneto-optical medium layer. The image sensor is configured to receive linearly polarized light emerging from the analyzer.

In the fingerprint sensor of the embodiment of the present application, when the user's fingerprint does not press the magnetic film, the intensity of the linearly polarized light passing through the magneto-optical medium layer and the analyzer does not change, so the image on the image sensor does not change. When the user's fingerprint presses the magnetic film, the magnetic induction intensity of the magnetic field generated by the magnetic film changes accordingly. Therefore, in the area corresponding to the fingerprint, the light intensity of the linearly polarized light that passes through the magneto-optical medium layer and the analyzer and emerges changes. The intensity of light received on the image sensor changes, causing the image on the image sensor to change and imaging the corresponding fingerprint outline. Then, by identifying and comparing the fingerprint outline, the electronic device executes the corresponding instructions.

When the user's fingerprint is in a wet state and the user's fingerprint comes into contact with the magnetic film, the user's skin and the magnetic film will squeeze the liquid together, causing the liquid to flow to other areas. The thickness of the area will change, so that the magnetic induction intensity will still change and will not be affected by the liquid. Therefore, the fingerprint sensor can still accurately obtain fingerprint data, effectively improve the recognition accuracy of the fingerprint sensor, reduce the possibility of fingerprint recognition failure, and improve the convenience and experience of using electronic devices.

In a possible implementation, the light emitting component includes a light emitting unit and a polarizer. The polarizer is arranged between the light-emitting unit and the magneto-optical medium layer. The polarizer is configured to convert the light emitted from the light-emitting unit into linearly polarized light. The polarizer has a second polarization direction that allows light to pass through. The first polarization direction intersects the second polarization direction. In the initial state when the fingerprint sensor is not in contact with the fingerprint, the linearly polarized light emitted from the polarizer passes through the magneto-optical medium layer and the analyzer, and then part of the linearly polarized light can pass through the analyzer, thereby allowing the image sensor to receive The surface displays a predetermined brightness.

In a possible implementation, the light emitting component includes a light guide layer and a polarizer. The polarizer is arranged between the light guide layer and the magneto-optical medium layer. The polarizer is configured to convert light emitted from the light guide layer into linearly polarized light. The polarizer has a second polarization direction that allows light to pass through. The first polarization direction intersects the second polarization direction. In the fingerprint sensor, the magnetic film, light guide layer, polarizer, magneto-optical medium layer and analyzer do not need to input or output electrical signals, so there is no need to set up additional corresponding circuit modules, making the overall circuit module design of the fingerprint sensor Simple, thus making the overall structure of the fingerprint sensor simple.

In a possible implementation, the angle between the first polarization direction and the second polarization direction ranges from 70° to 80°.

In a possible implementation, a polarizer is directly provided on the surface of the magneto-optical medium layer facing the magnetic film. There are no additional connections between the polarizer and the magneto-optical medium layer, so on the one hand, the linearly polarized light emitted from the polarizer can be directly incident into the magneto-optical medium layer, which is beneficial to reducing the attenuation rate of the linearly polarized light. At the same time, it is helpful to reduce the possibility of linearly polarized light being refracted or reflected in additional connectors and causing interference to linearly polarized light; on the other hand, it can reduce the overall thickness of the polarizer and the magneto-optical medium layer, which is beneficial to Ensure that the magnetic field of the magnetic film effectively acts on the magneto-optical medium layer, and reduce the weak magnetic induction intensity at the magneto-optical medium layer due to the large overall thickness of the polarizer and magneto-optical medium layer, making it impossible to make the lines in the magneto-optical medium layer It is possible that the polarized light rotates or the rotation angle does not reach a predetermined angle; on the other hand, it can help reduce the overall thickness of the fingerprint sensor, thereby making the overall structure of the fingerprint sensor more compact and realizing a miniaturized design of the fingerprint sensor.

In a possible implementation, the analyzer is directly disposed on the surface of the magneto-optical medium layer facing the image sensor. There are no additional connections between the analyzer and the magneto-optical medium layer, so the linearly polarized light emitted from the magneto-optical medium layer can be directly incident on the analyzer, which is beneficial to reducing the attenuation rate of the linearly polarized light and at the same time Reduce the possibility of linearly polarized light being refracted or reflected in additional connectors and causing interference to linearly polarized light.

In a possible implementation, the polarizer is a polarizing plate; or the analyzer is a polarizing plate. The thickness of the polarizer or analyzer itself is small, which is beneficial to reducing the overall thickness of the fingerprint sensor. When the polarizer is a polarizing plate, it can effectively reduce the possibility of adverse effects on the magnetic field of the magnetic film due to the large thickness of the polarizer itself.

In one possible implementation, the material of the magneto-optical medium layer is a rare earth garnet crystal, which can make the Verdet constant of the magneto-optical medium layer larger, which is beneficial to reducing the thickness of the magneto-optical medium layer.

In a possible implementation, the magnetic film is a nanomagnetic liquid film, so that the magnetic film has good flexibility and is easily deformed when pressed by a fingerprint.

In a possible implementation, the light emitting component includes a light emitting part. The light output part is arranged facing the magneto-optical medium layer. The light emitted from the light emitting component propagates toward the magneto-optical medium layer, thereby effectively reducing the amount of light emitted from the light emitting component toward the magnetic film, and reducing the light emitted from the light emitting component from propagating toward the magnetic film, causing the light reflected by the magnetic film or the light reflected by the finger itself to eventually be projected onto on the image sensor, thereby affecting the clarity of the fingerprint image on the image sensor and the possibility of fingerprint recognition accuracy.

In a possible implementation, the fingerprint sensor further includes a light-blocking layer. The light-isolating layer is disposed between the magnetic film and the light-emitting component. The light-isolating layer is configured to isolate the light-emitting component and the magnetic film, so that on the one hand, it can block the light emitted from the light-emitting component from propagating toward the magnetic film; on the other hand, it can block the external light from the fingerprint sensor from passing through the magnetic film and being incident on the magneto-optical medium and Image sensor, which helps reduce the possibility of external light imaging on the image sensor and affecting the clarity of the fingerprint image and the accuracy of fingerprint recognition.

In a possible implementation, a light-isolating layer is formed on the surface of the light-emitting component facing the magnetic film through a plating process or a coating process, so that the thickness of the light-isolating layer itself is smaller.

In a possible implementation, the material of the light-blocking layer is a material with light-absorbing properties. After the light emitted from the light-emitting component is incident on the light-isolating layer, the light-isolating layer can absorb the light, thereby helping to reduce the possibility of light reflection on the light-isolating layer, thereby reducing the risk of the light reflected from the light-isolating layer being imaged on the image sensor. The possibility of affecting the clarity of the fingerprint image and the accuracy of fingerprint recognition.

A second aspect of the present application provides an electronic device, which at least includes the above fingerprint sensor. The fingerprint sensor at least includes a light emitting component, a magnetic film, a magneto-optical medium layer, a polarizer and an image sensor. The light emitting component is configured to emit linearly polarized light. The magnetic film is arranged on one side of the light emitting component. The surface of the magnetic film facing away from the light emitting component is the fingerprint receiving area. The magneto-optical medium layer is disposed on the other side of the light emitting component. The magnetic film is arranged opposite to the magneto-optical medium layer. The magneto-optical medium layer is located in the magnetic field generated by the magnetic film. The magneto-optical medium layer is configured to receive linearly polarized light and rotate the linearly polarized light. The analyzer is disposed on the side of the magneto-optical medium layer facing away from the light emitting component. The analyzer has a first polarization direction that allows light to pass through. The vibration direction of linearly polarized light intersects the first polarization direction. The image sensor is arranged on the side of the analyzer facing away from the magneto-optical medium layer. The image sensor is configured to receive linearly polarized light emerging from the analyzer.

In a possible implementation, the light emitting component includes a light emitting unit and a polarizer. The polarizer is arranged between the light-emitting unit and the magneto-optical medium layer. The polarizer is configured to convert the light emitted from the light-emitting unit into linearly polarized light. The polarizer has a second polarization direction that allows light to pass through. The first polarization direction intersects the second polarization direction. In the initial state when the fingerprint sensor is not in contact with the fingerprint, the linearly polarized light emitted from the polarizer passes through the magneto-optical medium layer and the analyzer, and then part of the linearly polarized light can pass through the analyzer, thereby allowing the image sensor to receive The surface displays a predetermined brightness.

In a possible implementation, the light emitting component includes a light guide layer and a polarizer. The polarizer is arranged between the light guide layer and the magneto-optical medium layer. The polarizer is configured to convert light emitted from the light guide layer into linearly polarized light. The polarizer has a second polarization direction that allows light to pass through. The first polarization direction intersects the second polarization direction. In the fingerprint sensor, the magnetic film, light guide layer, polarizer, magneto-optical medium layer and analyzer do not need to input or output electrical signals, so there is no need to set up additional corresponding circuit modules, making the overall circuit module design of the fingerprint sensor Simple, thus making the overall structure of the fingerprint sensor simple.

In a possible implementation, the angle between the first polarization direction and the second polarization direction ranges from 70° to 80°.

In a possible implementation, a polarizer is directly provided on the surface of the magneto-optical medium layer facing the magnetic film. There are no additional connections between the polarizer and the magneto-optical medium layer, so on the one hand, the linearly polarized light emitted from the polarizer can be directly incident into the magneto-optical medium layer, which is beneficial to reducing the attenuation rate of the linearly polarized light. At the same time, it is helpful to reduce the possibility of linearly polarized light being refracted or reflected in additional connectors and causing interference to linearly polarized light; on the other hand, it can reduce the overall thickness of the polarizer and the magneto-optical medium layer, which is beneficial to Ensure that the magnetic field of the magnetic film effectively acts on the magneto-optical medium layer, and reduce the weak magnetic induction intensity at the magneto-optical medium layer due to the large overall thickness of the polarizer and magneto-optical medium layer, making it impossible to make the lines in the magneto-optical medium layer It is possible that the polarized light rotates or the rotation angle does not reach a predetermined angle; on the other hand, it can help reduce the overall thickness of the fingerprint sensor, thereby making the overall structure of the fingerprint sensor more compact and realizing a miniaturized design of the fingerprint sensor.

In a possible implementation, the analyzer is directly disposed on the surface of the magneto-optical medium layer facing the image sensor. There are no additional connections between the analyzer and the magneto-optical medium layer, so the linearly polarized light emitted from the magneto-optical medium layer can be directly incident on the analyzer, which is beneficial to reducing the attenuation rate of the linearly polarized light and at the same time Reduce the possibility of linearly polarized light being refracted or reflected in additional connectors and causing interference to linearly polarized light.

In a possible implementation, the polarizer is a polarizing plate; or the analyzer is a polarizing plate. The thickness of the polarizer or analyzer itself is small, which is beneficial to reducing the overall thickness of the fingerprint sensor. When the polarizer is a polarizing plate, it can effectively reduce the possibility of adverse effects on the magnetic field of the magnetic film due to the large thickness of the polarizer itself.

In a possible implementation, the thickness of the magneto-optical medium layer is greater than the thickness of the polarizer. The thickness of the magneto-optical medium layer is greater than the thickness of the analyzer.

In one possible implementation, the material of the magneto-optical medium layer is a rare earth garnet crystal, which can make the Verdet constant of the magneto-optical medium layer larger, which is beneficial to reducing the thickness of the magneto-optical medium layer.

In a possible implementation, the magnetic film is a nanomagnetic liquid film, so that the magnetic film has good flexibility and is easily deformed when pressed by a fingerprint.

In a possible implementation, the light emitting component includes a light emitting part. The light output part is arranged facing the magneto-optical medium layer. The light emitted from the light emitting component propagates toward the magneto-optical medium layer, thereby effectively reducing the amount of light emitted from the light emitting component toward the magnetic film, and reducing the light emitted from the light emitting component from propagating toward the magnetic film, causing the light reflected by the magnetic film or the light reflected by the finger itself to eventually be projected onto on the image sensor, thereby affecting the clarity of the fingerprint image on the image sensor and the possibility of fingerprint recognition accuracy.

In a possible implementation, the fingerprint sensor further includes a light-blocking layer. The light-isolating layer is disposed between the magnetic film and the light-emitting component. The light-isolating layer is configured to isolate the light-emitting component and the magnetic film, so that on the one hand, it can block the light emitted from the light-emitting component from propagating toward the magnetic film; on the other hand, it can block the external light from the fingerprint sensor from passing through the magnetic film and being incident on the magneto-optical medium and Image sensor, which helps reduce the possibility of external light imaging on the image sensor and affecting the clarity of the fingerprint image and the accuracy of fingerprint recognition.

In a possible implementation, a light-isolating layer is formed on the surface of the light-emitting component facing the magnetic film through a plating process or a coating process, so that the thickness of the light-isolating layer itself is smaller.

In a possible implementation, the material of the light-blocking layer is a material with light-absorbing properties. After the light emitted from the light-emitting component is incident on the light-isolating layer, the light-isolating layer can absorb the light, thereby helping to reduce the possibility of light reflection on the light-isolating layer, thereby reducing the risk of the light reflected from the light-isolating layer being imaged on the image sensor. The possibility of affecting the clarity of the fingerprint image and the accuracy of fingerprint recognition.

Description of the drawings

Figure 1 is a schematic structural diagram of an electronic device provided by an embodiment of the present application;

Figure 2 is a schematic diagram of the exploded structure of the electronic device provided by the implementation of this application;

Figure 3 is a partial cross-sectional structural schematic diagram of a fingerprint sensor provided by an embodiment of the present application;

Figure 4 is a schematic diagram of a state where the fingerprint sensor and the fingerprint are not in contact according to an embodiment of the present application;

Figure 5 is a schematic diagram of a state in which a fingerprint sensor is in contact with a fingerprint according to an embodiment of the present application;

Figure 6 is a schematic diagram of a partially exploded structure of a fingerprint sensor provided by an embodiment of the present application;

Figure 7 is a schematic diagram of the state of the magnetic induction intensity when the magnetic film and the fingerprint are not in contact according to an embodiment of the present application;

Figure 8 is a schematic diagram of the magnetic induction intensity when a magnetic film contacts a fingerprint according to an embodiment of the present application;

Figure 9 is a schematic partial cross-sectional structural diagram of a fingerprint sensor provided by another embodiment of the present application;

FIG. 10 is a schematic partial cross-sectional structural diagram of a fingerprint sensor provided by yet another embodiment of the present application.

Tag description:

10. Electronic equipment;

20. Display components;

30. Shell; 30a. Opening;

40. Motherboard;

50. Electronic devices;

60. Fingerprint sensor;

61. Light emitting component; 61a, light emitting part; 611, light emitting unit; 612, polarizer; 613, light guide layer;

62. Magnetic film; 62a. Fingerprint receiving area;

63. Magneto-optical medium layer;

64. Polarizer;

65. Image sensor;

66. Light barrier layer;

70. External light source;

100. Finger; 110. Fingerprint; 110a, protrusion; 110b, concave part;

X, thickness direction;

P1, first polarization direction;

P2, second polarization direction.

Detailed ways

The electronic device in the embodiment of the present application may be called user equipment (UE) or terminal (terminal), etc., for example, the electronic device may be a tablet computer (portable android device, PAD), personal digital assistant (personal digital assistant, PDA), handheld devices with wireless communication functions, computing devices, vehicle-mounted devices, wearable devices, virtual reality (VR) terminal devices, augmented reality (AR) terminal devices, industrial control (industrial control) Wireless terminals, wireless terminals in self-driving, wireless terminals in remote medical, wireless terminals in smart grid, wireless terminals in transportation safety, smart city ), mobile terminals or fixed terminals such as wireless terminals in smart homes. In the embodiments of this application, there is no specific limitation on the form of the terminal device.

In the embodiment of the present application, FIG. 1 schematically shows the structure of an electronic device 10 according to an embodiment. Referring to FIG. 1 , the electronic device 10 is a handheld device with a wireless communication function as an example for description. The handheld device with wireless communication function may be a mobile phone, for example.

FIG. 2 schematically shows a partially exploded structure of the electronic device 10 . Referring to FIG. 2 , the electronic device 10 according to the embodiment of the present application includes a display assembly 20 , a housing 30 , a motherboard 40 and an electronic device 50 .

The display component 20 has a display area for displaying image information. The display component 20 is installed on the housing 30, and the display area of the display component 20 is exposed to facilitate presenting image information to the user. The motherboard 40 is connected to the casing 30 and is located inside the display assembly 20 , so that the motherboard 40 is not easily visible to the user outside the electronic device 10 . The electronic device 50 is provided on the motherboard 40 . The main board 40 may be a printed circuit board (PCB). The electronic device 50 is welded to the motherboard 40 through a welding process. The electronic device 50 includes, but is not limited to, a central processing unit (CPU), an intelligent algorithm chip, or a power management IC (PMIC).

The electronic device 10 provided in the embodiment of the present application also includes a fingerprint sensor 60 . In some examples, the fingerprint sensor 60 may be disposed on the back of the electronic device 10 . Corresponding openings 30 a are provided on the back of the housing 30 to avoid the fingerprint sensor 60 . The fingerprint sensor 60 may cover the opening 30a. The opening 30 a of the housing 30 also has a guiding function, so that the user can easily place his finger on the fingerprint sensor 60 when holding the electronic device 10 . It is understandable that the fingerprint sensor 60 can also be disposed on the side of the housing 30 to implement the side fingerprint recognition function. The fingerprint sensor 60 can be communicatively connected with the motherboard 40 . When the user uses the electronic device 10 , the user's fingerprint data can be generated in advance by the fingerprint sensor 60 and stored in the electronic device 10 , so that the electronic device 10 can be encrypted through fingerprint encryption. When the user uses the electronic device 10 again, the electronic device 10 can identify the user's fingerprint through the fingerprint sensor 60. If it is determined that the current fingerprint matches the pre-stored fingerprint information, the electronic device 10 executes unlocking or other corresponding instructions. If it is determined that the current fingerprint does not match the pre-stored fingerprint information, the electronic device 10 does not execute relevant instructions and can maintain the current state.

It should be noted that the fingerprint 110 is formed by uneven skin, so that the fingerprint 110 includes protrusions 110a and concave portions 110b. For example, there is a recess 110b between two adjacent protrusions 110a. The user's fingerprint 110 may be the skin texture of the finger 100, palm, toe or sole. This application uses the fingerprint 110 of the finger 100 as an example for description, but does not limit the scope of protection of this application.

The implementation of the fingerprint sensor 60 provided in the embodiment of the present application is described below.

FIG. 3 schematically shows a partial cross-sectional structure of a fingerprint sensor 60 according to an embodiment. As shown in FIG. 3 , the fingerprint sensor 60 in the embodiment of the present application at least includes a light emitting component 61 , a magnetic film 62 , a magneto-optical medium layer 63 , a polarizer 64 and an image sensor 65 .

The light emitting component 61 is configured to emit linearly polarized light. Linearly polarized light can refer to light waves whose light vector vibrates only in one fixed direction. The light emitting component 61 is used to provide linearly polarized light for the fingerprint sensor 60 , and the emitted linearly polarized light can be used as excitation light for the fingerprint sensor 60 . For example, the linearly polarized light emitted by the light emitting component 61 may include visible light.

Along the thickness direction X of the magnetic film 62 , the magnetic film 62 is located on one side of the light emitting component 61 . The surface of the magnetic film 62 facing away from the light emitting component 61 is the fingerprint receiving area 62a. The fingerprint receiving area 62a is an area for contact with the user's skin. The magnetic film 62 itself has magnetism and can generate a magnetic field. The magnetic film 62 itself is flexible and will deform in the area pressed by the fingerprint 110.

FIG. 4 schematically shows a state where the fingerprint sensor 60 and the fingerprint 110 are not in contact. Referring to FIG. 4 , the user's finger 100 is located above the fingerprint receiving area 62 a. The magnetic film 62 is not in contact with the fingerprint 110 of the finger 100 . The magnetic film 62 is in an initial state. FIG. 5 schematically shows a state in which the fingerprint sensor 60 is in contact with the fingerprint 110 . As shown in FIG. 5 , the magnetic film 62 undergoes compression deformation in the area pressed by the protrusion 110 a of the fingerprint 110 and becomes smaller in thickness, while the area of the magnetic film 62 corresponding to the concave portion 110 b of the fingerprint 110 undergoes bulge deformation and becomes thicker. When the thickness of the magnetic film 62 is deformed, the magnetic field distribution corresponding to the deformed area will change accordingly, and accordingly, the magnitude of the magnetic induction intensity will also change. After the fingerprint 110 recognition work is completed and the user removes the finger 100 from the fingerprint receiving area 62a, the magnetic film 62 can return to the initial state under its own elastic recovery force, thereby not affecting the next fingerprint 110 pressing and fingerprint 110 recognition operations.

The magneto-optical medium layer 63 is located on the other side of the light-emitting component 61, so that the magnetic film 62 and the magneto-optical medium layer 63 are arranged oppositely, that is, the magnetic film 62 and the magneto-optical medium layer 63 are located on both sides of the light-emitting component 61 respectively. The magneto-optical medium layer 63 is located in the magnetic field of the magnetic film 62 . The magneto-optical medium layer 63 is configured to receive the linearly polarized light emitted by the light emitting component 61 and rotate the linearly polarized light. The magneto-optical medium layer 63 is a medium layer that can produce a magneto-optical effect.

FIG. 6 schematically shows a partially exploded structure of the fingerprint sensor 60 . As shown in FIG. 6 , since the magneto-optical medium layer 63 is located in the magnetic field of the magnetic film 62 , after the linearly polarized light is incident on the magneto-optical medium layer 63 and propagates along the direction of the magnetic field, the magneto-optical medium layer 63 in the magnetic field will The linearly polarized light is rotated, so that there is an included angle β between the linearly polarized light emitted from the magneto-optical medium layer 63 and the linearly polarized light incident on the magneto-optical medium layer 63 . The angle β is also called the optical rotation angle. The direction of the magnetic field is the same as the thickness direction X of the magnetic thin film 62 . The rotation plane when the linearly polarized light is rotated is perpendicular to the thickness direction X of the magnetic film 62 . For example, the value range of the included angle β may be, but is not limited to, 2° to 30°. For example, the value range of the included angle β may be, but is not limited to, 5°, 8°, 10°, 15° or 20°. The size of the angle β is positively related to the thickness d of the magneto-optical medium layer 63, the magnetic induction intensity B, and the Verdet constant of the material of the magneto-optical medium layer 63 itself. When at least one of the thickness d of the magneto-optical medium layer 63, the magnetic induction intensity B, and the Verdet constant of the material of the magneto-optical medium layer 63 itself increases, the angle β increases, and accordingly, at least one of them decreases. If it is small, the angle β will decrease.

For example, FIG. 7 schematically shows the state of the magnetic induction intensity when the magnetic film 62 is not in contact with the fingerprint 110 . Referring to FIG. 7 , when the fingerprint 110 of the finger 100 is not in contact with the magnetic film 62 , the magnetic film 62 is in an initial state, and the magnetic induction intensity of the magnetic field generated by it is B0. Each area of the magneto-optical medium layer 63 is located in a magnetic field with a magnetic induction intensity B0. The linearly polarized light emitted from each region of the magneto-optical medium layer 63 has the same optical rotation angle β.

FIG. 8 schematically shows the state of the magnetic induction intensity when the magnetic film 62 is in contact with the fingerprint 110 . As shown in FIG. 8 , when the user contacts the fingerprint 110 of the finger 100 with the magnetic film 62 and applies a pressing force, the pressed area of the magnetic film 62 deforms, causing the thickness to change, thereby causing the magnetic induction intensity of the magnetic field generated in this area. are B1 and B2 respectively, wherein the magnetic induction intensity of the magnetic field corresponding to the protrusion 110a of the fingerprint 110 is B1, and the magnetic induction intensity of the magnetic field corresponding to the concave portion 110b of the fingerprint 110 is B2. The thickness of the unpressed areas of the magnetic film 62 does not change, so that the magnetic induction intensity of the magnetic field generated in these areas remains B0. A partial area of the magneto-optical medium layer 63 is located in a magnetic field with a magnetic induction intensity of B0, while the area corresponding to the protrusion 110a of the fingerprint 110 is located in a magnetic field with a magnetic induction intensity of B1, and the area corresponding to the recessed portion 110b of the fingerprint 110 is located in a magnetic field with a magnetic induction intensity of B1. in the magnetic field of B2. Since the thickness of the magneto-optical medium layer 63 and the Verdet constant of its own material are the same, but any two of the magnetic induction intensity B0, the magnetic induction intensity B1 and the magnetic induction intensity B2 are different, the corresponding magnetic induction intensity on the magneto-optical medium layer 63 The optical rotation angle β of the linearly polarized light emitted from the areas of B0, magnetic induction intensity B1 and magnetic induction intensity B2 is different.

The analyzer 64 is located on the side of the magneto-optical medium layer 63 facing away from the light emitting component 61 . The analyzer 64 is used to receive the linearly polarized light emitted from the magneto-optical medium layer 63 . The analyzer 64 has a first polarization direction P1 that allows light to be transmitted. The vibration direction of linearly polarized light intersects the first polarization direction P1.

Since the vibration direction of the linearly polarized light intersects with the first polarization direction P1 of the analyzer 64 , a part of the linearly polarized light can pass through the analyzer 64 , and the light emitted from the analyzer 64 has a vibration direction consistent with the first polarization direction. P1 is the same linearly polarized light, so the intensity of the linearly polarized light emitted from the analyzer 64 is smaller than the intensity of the linearly polarized light incident on the analyzer 64 . For example, the greater the optical rotation angle β of the linearly polarized light emitted from the magneto-optical medium layer 63 , the greater the light intensity and the higher the brightness that the linearly polarized light can pass through the analyzer 64 . Correspondingly, the smaller the optical rotation angle β is, the smaller the intensity of linearly polarized light that can pass through the analyzer 64 is, and the lower the brightness.

The image sensor 65 is located on the side of the analyzer 64 facing away from the magneto-optical medium layer 63 . Image sensor 65 is configured to receive linearly polarized light emitted from analyzer 64 . The linearly polarized light emitted from each area of the analyzer 64 can be projected on the image sensor 65 to form a corresponding image.

For example, when the magnetic film 62 of the fingerprint sensor 60 does not contact the fingerprint 110, the magnetic induction intensity generated by the magnetic film 62 does not change. The angle of rotation of the linearly polarized light in the magneto-optical medium layer 63 is the same, so the image formed by the linearly polarized light passing through the analyzer 64 does not change.

When the fingerprint 110 of the finger 100 is placed on the magnetic film 62 of the fingerprint sensor 60, the protrusions 110a and recesses 110b of the fingerprint 110 cause the thickness of the magnetic film 62 to change, so that the areas on the magnetic film 62 corresponding to the protrusions 110a and the recesses 110b The degree of deformation is different, and the magnetic field distribution corresponding to the protrusions 110a and the concave portions 110b on the magnetic film 62 is different, so that the generated magnetic induction intensity is also different. In the area where the magnetic induction intensity does not change, the optical rotation angle β of the linearly polarized light in the magneto-optical medium layer 63 does not change, so the intensity of the light passing through the analyzer 64 does not change, and the image generated on the image sensor 65 does not change. Variety. In the area where the magnetic induction intensity changes, the optical rotation angle β of the linearly polarized light in the magneto-optical medium layer 63 will change, so the intensity of the light passing through the analyzer 64 will change, and the image generated on the image sensor 65 will change. , and then the corresponding outline of the fingerprint 110 can be imaged on the image sensor 65 . The image sensor 65 may convert image information into electrical signals and output them to the controller. The controller compares it with the original pre-stored fingerprint 110 data. If the two match, the electronic device 10 can execute instructions such as unlocking. If the two do not match, the electronic device 10 maintains the current state, such as a locked state.

In the fingerprint sensor 60 of the embodiment of the present application, when the user's fingerprint 110 does not press the magnetic film 62, the intensity of the linearly polarized light passing through the magneto-optical medium layer 63 and the analyzer 64 does not change, so the image on the image sensor 65 does not change. changes occur. When the user's fingerprint 110 presses the magnetic film 62, the magnetic induction intensity of the magnetic field generated by the magnetic film 62 changes accordingly. Therefore, in the area corresponding to the fingerprint 110, the lines that pass through the magneto-optical medium layer 63 and the analyzer 64 are emitted. The intensity of the polarized light changes, so that the intensity of the light received on the image sensor 65 changes, causing the image on the image sensor 65 to change and form a corresponding outline of the fingerprint 110 . Then, the electronic device 10 executes corresponding instructions by identifying and comparing the outline of the fingerprint 110 .

When the user's fingerprint 110 is in a wet state and the user's fingerprint 110 comes into contact with the magnetic film 62, the user's skin and the magnetic film 62 will squeeze the liquid together, causing the liquid to flow to other areas, so that the magnetic film 62 is in contact with the fingerprint 110. The thickness of the area corresponding to the protrusion 110a and the recess 110b will change, so that the magnetic induction intensity will still change and will not be affected by the liquid. Therefore, the fingerprint sensor 60 can still accurately obtain fingerprint 110 data, effectively improving the recognition accuracy of the fingerprint sensor 60 , reducing the possibility of fingerprint 110 recognition failure, and improving the convenience and experience of using the electronic device 10 .

In some implementable ways, as shown in FIG. 5 , the light emitting component 61 includes a light emitting unit 611 and a polarizer 612 . The light-emitting unit 611 itself can actively emit light when powered on. The light emitted by the light emitting unit 611 may include visible light. For example, the light emitting unit 611 may be a surface light source or a point light source. For example, the light emitting unit 611 may include a cold cathode fluorescent lamp (Cold Cathode Fluorescent Lamp, CCFL) or an organic light-emitting diode (OLED).

The polarizer 612 is disposed between the light emitting unit 611 and the magneto-optical medium layer 63 . Part of the light emitted from the light emitting unit 611 passes through the polarizer 612 . The polarizer 612 is configured to convert the light emitted from the light emitting unit 611 into linearly polarized light. Polarizer 612 has a second polarization direction P2 that allows light to pass through. Among the light emitted from the light-emitting unit 611, the light whose vibration direction is the same as the second polarization direction P2 can pass through the polarizer 612 and form linearly polarized light. After the light emitted from the light emitting unit 611 passes through the polarizer 612, the intensity of the linearly polarized light emitted from the polarizer 612 will decrease, that is, the intensity of the linearly polarized light is smaller than the intensity of the light emitted from the light emitting component 61.

In the fingerprint sensor 60 , the magnetic film 62 , the polarizer 612 , the magneto-optical medium layer 63 and the analyzer 64 do not require additional corresponding circuit modules, thus making the overall circuit module design of the fingerprint sensor 60 simple, thereby making the fingerprint sensor 60 The overall structure is simple.

In some examples, as shown in FIG. 6 , the first polarization direction P1 of the analyzer 64 intersects the second polarization direction P2 of the polarizer 612 . The angle between the first polarization direction P1 of the analyzer 64 and the second polarization direction P2 of the polarizer 612 may range from 70° to 80°. Therefore, in the initial state when the fingerprint sensor 60 is not in contact with the fingerprint 110, the linearly polarized light emitted from the polarizer 612 passes through the magneto-optical medium layer 63 and the analyzer 64, and then part of the linearly polarized light can pass through the analyzer. 64, so that the receiving surface of the image sensor 65 exhibits a predetermined brightness.

The resolution of the image formed by receiving light on the receiving surface of the image sensor 65 depends on the value of the angle between the first polarization direction P1 of the analyzer 64 and the second polarization direction P2 of the polarizer 612 and the optical rotation angle. The value of β is related. Therefore, appropriately selecting the angle between the first polarization direction P1 of the polarizer 612 and the second polarization direction P2 of the analyzer 64 can ensure that the image brightness and image resolution obtained on the image sensor 65 are both better. 110 images of fingerprints.

In other implementable ways, FIG. 9 schematically shows a partial cross-sectional structure of the fingerprint sensor 60 . As shown in FIG. 9 , the light emitting component 61 includes a light guide layer 613 and a polarizer 612 . The polarizer 612 is disposed between the light guide layer 613 and the magneto-optical medium layer 63 . The polarizer 612 is configured to convert light emitted from the light guide layer 613 into linearly polarized light. In some examples, external light source 70 is provided outside fingerprint sensor 60 . The external light source 70 may be located on the side of the light guide layer 613 . The light guide layer 613 is configured to receive light from the external light source 70 . The light guide layer 613 can guide and distribute the incident light from the outside to make the incident light uniform. The light that has been homogenized by the light guide layer 613 can be incident on the polarizer 612 . For example, the material of the light guide layer 613 may be polymethyl methacrylate (PMMA). The external light source 70 may include organic light emitters. For example, the external light source 70 may be disposed on one side of the light guide layer 613 . Alternatively, two or more external light sources 70 may be arranged at intervals along the circumferential direction of the light guide layer 613 .

In the fingerprint sensor 60, the magnetic film 62, the light guide layer 613, the polarizer 612, the magneto-optical medium layer 63 and the analyzer 64 do not require additional corresponding circuit modules, thus making the overall circuit module design of the fingerprint sensor 60 simple. , thereby making the overall structure of the fingerprint sensor 60 simple.

In some implementable ways, the fingerprint sensor 60 also includes a transparent adhesive layer (not shown in the figure). A transparent adhesive layer is provided between the surface of the light-emitting component 61 facing the magnetic film 62 and the magnetic film 62 to connect the light-emitting component 61 and the magnetic film 62 . A transparent adhesive layer is disposed between the surface of the magneto-optical medium layer 63 facing the magnetic film 62 and the polarizer 612 to connect the magneto-optical medium layer 63 and the polarizer 612 . A transparent adhesive layer is provided between the surface of the magneto-optical medium layer 63 facing the analyzer 64 and the analyzer 64 to connect the magneto-optical medium layer 63 and the analyzer 64 . The transparent adhesive layer has good light transmittance, which is conducive to reducing the attenuation rate of linearly polarized light when passing through the transparent adhesive layer, ensuring that the intensity of light passing through the transparent adhesive layer meets the requirements.

In other implementable ways, the polarizer 612 is directly disposed on the surface of the magneto-optical medium layer 63 facing the magnetic film 62 . There are no additional connections between the polarizer 612 and the magneto-optical medium layer 63. Therefore, on the one hand, the linearly polarized light emitted from the polarizer 612 can be directly incident into the magneto-optical medium layer 63, which is beneficial to reducing the linearly polarized light. The attenuation rate is conducive to reducing the possibility of linearly polarized light being refracted or reflected in additional connectors and causing interference to linearly polarized light; on the other hand, the polarizer 612 and the magneto-optical medium layer 63 can be reduced The overall thickness is conducive to ensuring that the magnetic field of the magnetic film 62 effectively acts on the magneto-optical medium layer 63, and reducing the deviation of the magnetic induction intensity at the magneto-optical medium layer 63 caused by the large overall thickness of the polarizer 612 and the magneto-optical medium layer 63. Weak, it is impossible to rotate the linearly polarized light in the magneto-optical medium layer 63 or the rotation angle does not reach the predetermined angle; on the other hand, it can be beneficial to reduce the overall thickness of the fingerprint sensor 60, thereby making the overall structure of the fingerprint sensor 60 It is more compact and can realize the miniaturization design of the fingerprint sensor 60 .

In some examples, a layered polarizer 612 is formed on the surface of the magneto-optical medium layer 63 facing the magnetic film 62 through a plating process or a coating process, so that the thickness of the polarizer 612 itself is smaller.

In other implementable ways, the analyzer 64 is directly disposed on the surface of the magneto-optical medium layer 63 facing the image sensor 65 . There are no additional connections between the analyzer 64 and the magneto-optical medium layer 63, so the linearly polarized light emitted from the magneto-optical medium layer 63 can be directly incident on the analyzer 64, which is beneficial to reducing the attenuation rate of the linearly polarized light. , and at the same time, it is beneficial to reduce the possibility of linearly polarized light being refracted or reflected in additional connectors and causing interference to linearly polarized light.

In some examples, a layered analyzer 64 is formed on the surface of the magneto-optical medium layer 63 facing the image sensor 65 through a plating process or a coating process, so that the thickness of the analyzer 64 itself is smaller.

In some implementable ways, the polarizer 612 or the analyzer 64 is a polarizing plate, so that the thickness of the polarizer 612 or the analyzer 64 itself is small, which is beneficial to reducing the overall thickness of the fingerprint sensor 60 . When the polarizer 612 is a polarizing plate, the possibility of adversely affecting the magnetic field of the magnetic film 62 due to the large thickness of the polarizer 612 can be effectively reduced. The polarizing plate can be a polarizing optical device that produces linearly polarized light.

In some possible implementations, both the polarizer 612 and the analyzer 64 are polarizing plates.

In some examples, the polarizing plate may include a layer structure formed by processing a material with a linear polarization function. For example, the polarizing plate may include a protective film and a polarizing layer. The polarizing layer is located between the two protective films. The polarizing layer plays the role of polarization. The protective film has high light transmittance, good water resistance and high mechanical strength. Exemplarily, the material of the polarizing layer may be polyvinyl alcohol (PVA). The material of the protective film may be triacetylcellulose (TAC).

In some implementable ways, the thickness of the magneto-optical medium layer 63 is greater than the thickness of the polarizer 612 . The thickness of the magneto-optical medium layer 63 is greater than the thickness of the analyzer 64 . When linearly polarized light propagates through the magneto-optical medium layer 63, the thickness d of the magneto-optical medium layer 63 is positively related to the size of the optical rotation angle β. When the magnetic induction intensity B of the magnetic field generated by the magnetic film 62 and the Verdet constant of the magneto-optical medium layer 63 remain unchanged, the smaller the thickness d of the magneto-optical medium layer 63, the smaller the optical rotation angle β, correspondingly , the greater the thickness d of the magneto-optical medium layer 63, the greater the optical rotation angle β. Therefore, the thickness d of the magneto-optical medium layer 63 needs to be appropriately designed to ensure that the value of the optical rotation angle β meets the requirements.

If the optical rotation angle β is too small, for example, less than 2°, there is a possibility that the light intensity of the linearly polarized light passing through the analyzer 64 will be weak, resulting in darker image brightness and lower image resolution that can be obtained on the image sensor 65 . Poor fingerprint 110 images reduce fingerprint 110 recognition accuracy.

When the optical rotation angle β is too large, for example, greater than 8°, there is a possibility that the thickness d of the magneto-optical medium layer 63 will be too large, thereby making the overall thickness of the fingerprint sensor 60 too large, which is not conducive to the miniaturization design of the fingerprint sensor 60 .

In some examples, the thickness of the magneto-optical medium layer 63 may range from, but is not limited to, 0.3 mm to 0.8 mm. For example, the thickness of the magneto-optical medium layer 63 may be 0.5 mm.

In some feasible ways, the magneto-optical medium layer 63 has a relatively high hardness and is not easily deformed under force. The material of the magneto-optical medium layer 63 is rare earth garnet crystal, which can make the Verdet constant of the magneto-optical medium layer 63 larger, which is beneficial to reducing the thickness of the magneto-optical medium layer 63 . In addition, the wavelength of the linearly polarized light can be selected according to the optimal working band of the material of the magneto-optical medium layer 63 , thereby ensuring that the linearly polarized light achieves a better rotation angle after passing through the magneto-optical medium layer 63 . In some examples, the material of the magneto-optical medium layer 63 may be, but is not limited to, yttrium iron garnet crystal (YIG). Correspondingly, the wavelength of linearly polarized light may be 589 nanometers.

In some feasible ways, the magnetic film 62 is a nanomagnetic liquid film, so that the magnetic film 62 has good flexibility and is easily deformed when pressed by the fingerprint 110 of the finger 100 . In some examples, the thickness of the magnetic film 62 may range from, but is not limited to, 0.3 mm to 0.7 mm. For example, the thickness of the magnetic film 62 may be 0.5 mm.

In some implementable ways, the light emitting component 61 includes a light emitting part 61a. The light emitting part 61 a of the light emitting component 61 is disposed facing the magneto-optical medium layer 63 . The light emitting component 61 can emit light from one side. The light emitted from the light emitting part 61a propagates towards the magneto-optical medium layer 63 and can be incident on the polarizer 612, thereby effectively reducing the amount of light emitted from the light emitting part 61a towards the magnetic film 62 and reducing the amount of light emitted from the light emitting part 61a propagating towards the magnetic film 62. As a result, the light reflected by the magnetic film 62 or the light reflected by the finger 100 itself is finally projected onto the image sensor 65 , thereby affecting the clarity of the fingerprint 110 image on the image sensor 65 and the possibility of fingerprint 110 recognition accuracy.

In some implementable ways, FIG. 10 schematically shows a partial cross-sectional structure of the fingerprint sensor 60 . As shown in FIG. 10 , the fingerprint sensor 60 also includes a light-blocking layer 66 . The light-blocking layer 66 is disposed between the magnetic film 62 and the light-emitting component 61 . The light-blocking layer 66 is configured to isolate the light-emitting component 61 and the magnetic film 62, so that on the one hand, it can block the light emitted from the light-emitting component 61 from propagating toward the magnetic film 62; on the other hand, it can block the external light from the fingerprint sensor 60 from passing through the magnetic film. 62 is incident on the magneto-optical medium and the image sensor 65, which is beneficial to reducing the possibility that external light is imaged on the image sensor 65 and affects the clarity of the fingerprint 110 image and the fingerprint 110 recognition accuracy.

On the premise that the light-blocking layer 66 meets the light-blocking requirements, the smaller the thickness of the light-blocking layer 66, the smaller the impact of the light-blocking layer 66 on the magnetic field generated by the magnetic film 62, and at the same time, it can help reduce the thickness of the fingerprint sensor 60, thereby reducing the thickness of the fingerprint sensor 60. The overall structure of the fingerprint sensor 60 is made more compact, and a miniaturized design of the fingerprint sensor 60 can be achieved. When the thickness of the light-isolating layer 66 is too large, the distance between the magnetic film 62 and the magneto-optical medium layer 63 is large, so that the magnetic field generated by the magnetic film 62 has a weakened effect on the magneto-optical medium layer 63 , resulting in the magneto-optical medium layer 63 The magnetic induction intensity at the magneto-optical medium layer 63 is weak, so there is a possibility that the linearly polarized light in the magneto-optical medium layer 63 does not rotate or the rotation angle of the linearly polarized light in the magneto-optical medium layer 63 does not reach a predetermined angle, which affects the fingerprint 110 recognition accuracy. and adversely affect accuracy.

In some examples, the light-isolating layer 66 is formed on the surface of the light-emitting component 61 facing the magnetic film 62 through a plating process or a coating process, so that the thickness of the light-isolating layer 66 itself is smaller.

In some examples, the material of the light-blocking layer 66 is a material with light-absorbing properties. After the light emitted from the light-emitting component 61 is incident on the light-isolating layer 66, the light-isolating layer 66 can absorb the light, thereby reducing the possibility of the light being reflected on the light-isolating layer 66, thereby reducing the possibility of the light reflected from the light-isolating layer 66 being reflected. The possibility of imaging on the image sensor 65 affecting the clarity of the fingerprint 110 image and the fingerprint 110 recognition accuracy.

In some implementable ways, the image sensor 65 may be a CMOS (Complementary Metal Oxide Semiconductor) sensor or a CCD (Charge Coupled Device) sensor.

In the description of the embodiments of this application, it should be noted that, unless otherwise clearly stated and limited, the terms "installation", "connection" and "connection" should be understood in a broad sense. For example, it can be a fixed connection or a fixed connection. Indirect connection through an intermediary can be the internal connection between two elements or the interaction between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the embodiments of this application can be understood according to specific circumstances.

The devices or elements mentioned in the embodiments of this application or by implication must have a specific orientation, be constructed and operate in a specific orientation, and therefore cannot be understood as limiting the embodiments of this application. In the description of the embodiments of this application, "plurality" means two or more, unless otherwise precisely and specifically specified.

The terms "first", "second", "third", "fourth", etc. (if present) in the description and claims of the embodiments of this application and the above-mentioned drawings are used to distinguish similar objects, and It is not necessary to describe a specific order or sequence. It is to be understood that the data so used are interchangeable under appropriate circumstances so that the embodiments of the application described herein can be practiced in sequences other than those illustrated or described herein.

In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, e.g., a process, method, system, product, or apparatus that encompasses a series of steps or units and need not be limited to those explicitly listed. Those steps or elements may instead include other steps or elements not expressly listed or inherent to the process, method, product or apparatus.

The term "plurality" as used herein means two or more. The term "and/or" in this article is just an association relationship that describes related objects, indicating that three relationships can exist. For example, A and/or B can mean: A exists alone, A and B exist simultaneously, and they exist alone. B these three situations. In addition, the character "/" in this article generally indicates that the related objects before and after are an "or" relationship; in the formula, the character "/" indicates that the related objects before and after are a "division" relationship.

It can be understood that the various numerical numbers involved in the embodiments of the present application are only for convenience of description and are not used to limit the scope of the embodiments of the present application.

It can be understood that in the embodiments of the present application, the size of the sequence numbers of the above-mentioned processes does not mean the order of execution. The execution order of each process should be determined by its functions and internal logic, and should not be used in the implementation of the present application. The implementation of the examples does not constitute any limitations.

Claims (12)

1. A fingerprint sensor (60), characterized in that it comprises at least:

a light-emitting assembly (61) configured to emit linearly polarized light;

the magnetic film (62) is arranged on one side of the light emitting component (61), and the surface of the magnetic film (62) facing away from the light emitting component (61) is a fingerprint receiving area (62 a); wherein the magnetic film (62) is a magnetic film having flexibility;

a magneto-optical medium layer (63) disposed on the other side of the light emitting component (61), the magnetic film (62) being disposed opposite to the magneto-optical medium layer (63), the magneto-optical medium layer (63) being located in a magnetic field generated by the magnetic film (62), the magneto-optical medium layer (63) being configured to receive the linearly polarized light and rotate the linearly polarized light;

an analyzer (64) disposed on a side of the magneto-optical medium layer (63) facing away from the light-emitting element (61), the analyzer (64) having a first polarization direction (P1) allowing light to pass therethrough, and a vibration direction of the linearly polarized light intersecting the first polarization direction (P1);

an image sensor (65) disposed on a side of the analyzer (64) facing away from the magneto-optical medium layer (63), the image sensor (65) being configured to receive the linearly polarized light exiting the analyzer (64);

When the fingerprint presses the magnetic film (62), the thickness of the region of the magnetic film (62) corresponding to the protrusion and the concave part of the fingerprint changes, so that the magnetic induction intensity of the magnetic field generated by the magnetic film (62) in the region changes, the light intensity of the linearly polarized light which passes through the magneto-optical medium layer (63) and the analyzer (64) and exits changes, and the light intensity received by the image sensor (65) correspondingly changes to form a fingerprint profile.

2. Fingerprint sensor (60) according to claim 1, wherein the light exit assembly (61) comprises a light emitting unit (611) and a polarizer (612), the polarizer (612) being arranged between the light emitting unit (611) and the magneto-optical medium layer (63), the polarizer (612) being configured to convert light rays exiting the light emitting unit (611) into the linearly polarized light, the polarizer (612) having a second polarization direction (P2) allowing light rays to pass through, the first polarization direction (P1) intersecting the second polarization direction (P2).

3. The fingerprint sensor (60) of claim 1, wherein the light exit assembly (61) comprises a light guiding layer (613) and a polarizer (612), the polarizer (612) being arranged between the light guiding layer (613) and the magneto-optical medium layer (63), the polarizer (612) being configured to convert light rays exiting from the light guiding layer (613) into the linearly polarized light, the polarizer (612) having a second polarization direction (P2) allowing light rays to pass through, the first polarization direction (P1) intersecting the second polarization direction (P2).

4. A fingerprint sensor (60) according to claim 2 or 3, characterized in that the angle between the first polarization direction (P1) and the second polarization direction (P2) is in the range of 70 ° to 80 °.

5. A fingerprint sensor (60) according to claim 2 or 3, wherein the polarizer (612) is provided directly on the surface of the magneto-optical medium layer (63) facing the magnetic thin film (62); alternatively, the analyzer (64) is directly disposed on a surface of the magneto-optical medium layer (63) facing the image sensor (65).

6. A fingerprint sensor (60) according to claim 2 or 3, wherein the polarizer (612) is a polarizer; alternatively, the analyzer (64) is a polarizer.

7. A fingerprint sensor (60) according to any one of claims 1 to 3, wherein the material of the magneto-optical medium layer (63) is a rare earth garnet crystal; alternatively, the magnetic film (62) is a nano magnetic liquid film.

8. A fingerprint sensor (60) according to any one of claims 1-3, wherein the light exit assembly (61) comprises a light exit portion (61 a), the light exit portion (61 a) being arranged facing the magneto-optical medium layer (63).

9. A fingerprint sensor (60) according to any one of claims 1-3, wherein the fingerprint sensor (60) further comprises a light barrier layer (66), the light barrier layer (66) being arranged between the magnetic thin film (62) and the light extraction assembly (61).

10. The fingerprint sensor (60) of claim 9, wherein the light blocking layer (66) is formed by a plating process or a coating process on a surface of the light emitting component (61) facing the magnetic thin film (62).

11. The fingerprint sensor (60) of claim 9, wherein the light blocking layer (66) is of a material having light absorbing properties.

12. Electronic device (10), characterized in that it comprises at least a fingerprint sensor (60) according to any one of claims 1 to 11.