Fingerprint recognition device, display screen and electronic device

Abstract

The embodiments of the present application provide a fingerprint recognition device, a display screen, and an electronic device, which can effectively improve the performance of fingerprint recognition. The fingerprint recognition device is applied to an electronic device including a display screen, the display screen does not include a polarizer, and the fingerprint recognition device includes: a linear polarizer array, the polarization directions of two adjacent linear polarizers in the linear polarizer array are different, the linear polarizer array includes multiple groups of linear polarizers and each group of linear polarizers includes at least two adjacent linear polarizers, and the polarization directions of the linear polarizers in each group of linear polarizers are different from each other; a pixel unit array, which is arranged below the linear polarizer array, the pixel unit array includes multiple groups of pixel units, each group of pixel units in the multiple groups of pixel units includes at least two pixel units and corresponds to a group of linear polarizers in the linear polarizer array, each pixel unit in each group of pixel units is used to receive an optical signal, and the pixel values ​​of at least two pixel units in each group of pixel units are used to obtain a fingerprint image.

Description

Technical Field

[0001] The embodiments of the present application relate to the field of fingerprint recognition technology, and more specifically, to a fingerprint recognition device, a display screen, and an electronic device. Background Art

[0002] With the advent of the era of full-screen mobile phones, the application of fingerprint recognition devices set under or inside the screen in mobile phones and other terminal devices has also been widely developed. During the fingerprint recognition process, the fingerprint recognition device can not only receive the fingerprint light signal with fingerprint information reflected by the finger surface, but also receive the light signal reflected by the inside of the finger and the ambient light signal. The light signal reflected by the inside of the finger and the ambient light signal may affect the fingerprint recognition performance.

[0003] Therefore, how to avoid the influence of light signals reflected inside the finger and ambient light signals on fingerprint recognition in order to improve fingerprint recognition performance is an urgent problem to be solved. Summary of the invention

[0004] The embodiments of the present application provide a fingerprint recognition device, a display screen, and an electronic device, which can effectively improve the performance of fingerprint recognition.

[0005] In a first aspect, a fingerprint recognition device is provided, which is applied to an electronic device including a display screen, wherein the display screen does not include a polarizing plate, and the fingerprint recognition device includes: a linear polarizing plate array, including multiple groups of linear polarizing plates, each group of the multiple groups of linear polarizing plates includes at least two adjacent linear polarizing plates, and the polarization directions of the linear polarizing plates in each group of linear polarizing plates are different from each other; a pixel unit array, which is arranged below the linear polarizing plate, the pixel unit array includes multiple groups of pixel units, each group of pixel units in the multiple groups of pixel units includes at least two pixel units and corresponds to a group of linear polarizing plates in the linear polarizing plate array, each pixel unit in each group of pixel units is used to receive a light signal, the light signal includes a first light signal that is returned by a linearly polarized light signal emitted by a light source through a finger surface above the display screen, a second light signal that is returned by the linearly polarized light signal emitted by the light source through an inner part of the finger above the display screen, and an ambient light signal, and the pixel values ​​of at least two pixel units in each group of pixel units are used to obtain a fingerprint image.

[0006] In some possible embodiments, each group of linear polarizers includes two linear polarizers.

[0007] In some possible embodiments, polarization directions of the two linear polarizers are perpendicular to each other, and the polarization direction of the first light signal is parallel to the polarization direction of one of the two linear polarizers.

[0008] In some possible embodiments, the at least one group of pixel units includes a first pixel unit group, the first pixel unit group includes a pixel unit U and a pixel unit V, wherein the absolute value of the difference between the output signal of the pixel unit U and the output signal of the pixel unit V is used to determine the output signal LI of the first pixel unit group for the first light signal. OP , the output signal LI of the first optical signal OP Used to obtain the fingerprint image.

[0009] In some possible embodiments, the output signal LI of the first optical signal OP is equal to the absolute value of the difference between the output signal of the pixel unit U and the output signal of the pixel unit V.

[0010] In some possible embodiments, the second light signal and the ambient light signal are natural light signals, and the output signal of the pixel unit U, the output signal of the pixel unit V, and the output signal LI of the first light signal are OP Used to determine the output signal LI of the first pixel unit group to the natural light signal ON .

[0011] In some possible embodiments, the output signal LI of the natural light signal ON satisfy:

[0012] LI ON =LI U +LI V -LI OP

[0013] Among them, LI U is the output signal of the pixel unit U, LI V is the output signal of the pixel unit V.

[0014] In some possible embodiments, each group of linear polarizers includes three linear polarizers.

[0015] In some possible embodiments, each set of linear polarizers includes three linear polarizers with a step size of 60°.

[0016] In some possible embodiments, the at least one group of pixel units includes a first pixel unit group, the first pixel unit group includes a pixel unit X, a pixel unit Y and a pixel unit Z, wherein the absolute value of the difference between the output signals of at least two pixel units among the pixel unit X, the pixel unit Y and the pixel unit Z is used to determine the output signal LI of the first pixel unit group for the first light signal. OP , the output signal LI of the first optical signal OP Used to obtain the fingerprint image.

[0017] In some possible embodiments, the second light signal and the ambient light signal are natural light signals, and the output signal of the pixel unit X, the output signal of the pixel unit Y, the output signal of the pixel unit Z, and the output signal LI of the first light signal are OP Used to determine the output signal LI of the first pixel unit group to the natural light signal ON .

[0018] In some possible embodiments, the output signal LI of the first optical signal OP It is equal to the absolute value of the difference between the output signals of any two pixel units.

[0019] In some possible embodiments, the output signal LI of the natural light signal ON satisfy:

[0020]

[0021] Among them, LI X is the output signal of the pixel unit X, LI Y is the output signal of the pixel unit Y, LI Z is the output signal of the pixel unit Z.

[0022] In some possible embodiments, the output signal LI of the first optical signal OP satisfy:

[0023]

[0024] Among them, LI X-Y is the difference between the output signal of the pixel unit X and the output signal of the pixel unit Y, LI Y-Z is the difference between the output signal of the pixel unit Y and the output signal of the pixel unit Z, LI Z-X is the difference between the output signal of the pixel unit Z and the output signal of the pixel unit X.

[0025] In some possible embodiments, the output signal LI of the natural light signal ON satisfy:

[0026]

[0027] Among them, LI X is the output signal of the pixel unit X, LI Y is the output signal of the pixel unit Y, LI Z is the output signal of the pixel unit Z.

[0028] In some possible embodiments, the output signal LI of the first optical signal OP satisfy:

[0029] LI OP =|LI X-Y |+|LI Y-Z |+|LI Z-X |

[0030] Among them, LI X-Y is the difference between the output signal of the pixel unit X and the output signal of the pixel unit Y, LI Y-Z is the difference between the output signal of the pixel unit Y and the output signal of the pixel unit Z, LI Z-X is the difference between the output signal of the pixel unit Z and the output signal of the pixel unit X.

[0031] In some possible embodiments, the output signal LI of the natural light signal ON satisfy:

[0032]

[0033] Among them, LI X is the output signal of the pixel unit X, LI Y is the output signal of the pixel unit Y, LI Z is the output signal of the pixel unit Z.

[0034] In some possible embodiments, each group of linear polarizers includes four linear polarizers.

[0035] In some possible embodiments, each group of linear polarizers includes four linear polarizers with a step of 45°.

[0036] In some possible embodiments, the at least one group of pixel units includes a first pixel unit group, the first pixel unit group includes pixel unit A, pixel unit B, pixel unit C and pixel unit D, wherein the absolute value of the difference between the output signals of at least two pixel units among the pixel unit A, pixel unit B, pixel unit C and pixel unit D is used to determine the output signal LI of the first pixel unit group for the first light signal. OP , the output signal LI of the first optical signal OP Used to obtain the fingerprint image.

[0037] In some possible embodiments, the polarization direction of the polarizer corresponding to the pixel unit A is perpendicular to the polarization direction of the polarizer corresponding to the pixel unit C, and the polarization direction of the polarizer corresponding to the pixel unit B is perpendicular to the polarization direction of the polarizer corresponding to the pixel unit D.

[0038] In some possible embodiments, the second light signal and the ambient light signal are natural light signals, and the output signal of the pixel unit A, the output signal of the pixel unit B, the output signal of the pixel unit C, the output signal of the pixel unit D, and the output signal LI of the first light signal are OP Used to determine the output signal LI of the first pixel unit group to the natural light signal ON .

[0039] In some possible embodiments, the pixel value LI OP is equal to the absolute value of the difference between the output signal of the pixel unit A and the output signal of the pixel unit C; or

[0040] The output signal LI of the first optical signal OP is equal to the absolute value of the difference between the output signal of the pixel unit B and the output signal of the pixel unit D.

[0041] In some possible embodiments, the output signal LI of the first optical signal OP satisfy:

[0042]

[0043] Among them, LI A-C is the difference between the output signal of the pixel unit A and the output signal of the pixel unit C, LI B-D is the difference between the output signal of the pixel unit B and the output signal of the pixel unit D.

[0044] In some possible embodiments, the output signal LI of the natural light signal ON satisfy:

[0045] LI ON =LI A +LI B +LI C +LI D -LI OP

[0046] Among them, LI A is the output signal of the pixel unit A, LI B is the output signal of the pixel unit B, LI C is the output signal of the pixel unit C, LI D is the output signal of the pixel unit D.

[0047] In some possible embodiments, the output signal LI of the first optical signal OP satisfy:

[0048] LI OP =|LI A-C |+|LI B-D |

[0049] Among them, LI A-C is the difference between the output signal of the pixel unit A and the output signal of the pixel unit C, LI B-D is the difference between the output signal of the pixel unit B and the output signal of the pixel unit D.

[0050] In some possible embodiments, the output signal LI of the natural light signal ON satisfy:

[0051]

[0052] Among them, LI A is the output signal of the pixel unit A, LI B is the output signal of the pixel unit B, LI C is the output signal of the pixel unit C, LI D is the output signal of the pixel unit D.

[0053] In some possible embodiments, the fingerprint recognition device is disposed under the display screen or inside the display screen.

[0054] In some possible embodiments, the display screen includes a display pixel layer. When the fingerprint recognition device is used to be arranged in the display screen, the fingerprint recognition device and the display pixel layer are arranged in the same layer.

[0055] In some possible embodiments, the light source is at least a portion of display pixels of the display screen.

[0056] In some possible embodiments, the display screen is a micro light emitting diode Micro-LED display screen, or the display screen is a mini light emitting diode Mini-LED display screen.

[0057] In some possible embodiments, the light source is an external light source, and the external light source is disposed below the display screen.

[0058] In a second aspect, a display screen is provided, the display screen does not include a polarizing plate, and the display screen includes: a display pixel layer and a fingerprint recognition device in the first aspect and any possible implementation thereof, wherein the display pixel layer and the fingerprint recognition device are arranged on the same layer.

[0059] According to a third aspect, an electronic device is provided, comprising: a display screen and the fingerprint recognition device according to the first aspect and any possible implementation thereof, wherein the fingerprint recognition device is arranged under the display screen or inside the display screen.

[0060] In the above technical solution, under the condition that the display screen does not have a polarizing plate, the fingerprint recognition device includes a linear polarizing plate array, and the light source emits a linearly polarized light signal, so that the first light signal returned through the finger surface is a linearly polarized light signal, the second light signal returned through the inside of the finger is a natural light signal, and the ambient light signal is also a natural light signal, so that the first light signal returned through the finger surface can be distinguished from (the second light signal returned through the inside of the finger + the ambient light signal) by polarization difference, so that the second light signal can be prevented from canceling the first light signal, thereby effectively enhancing the fingerprint signal. In addition, the above technical solution can also reduce the impact of the second light signal and the ambient light signal returned through the inside of the finger on fingerprint recognition, thereby further improving the fingerprint recognition performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0061] Figure 1 and Figure 2 It is a schematic diagram of the principle of under-screen optical fingerprint recognition technology.

[0062] Figure 3 is a schematic diagram of the structure of a display screen including a polarizing plate.

[0063] Figure 4 It is a schematic diagram of a fingerprint recognition device according to an embodiment of the present application.

[0064] Figure 5 It is a schematic diagram of a fingerprint recognition device according to an embodiment of the present application being arranged in a display screen.

[0065] Figure 6 is a schematic diagram of a fingerprint recognition device including an additional light source according to an embodiment of the present application.

[0066] Figure 7 1 is a schematic diagram of a set of linear polarizers according to an embodiment of the present application, including a pixel unit array corresponding to two linear polarizers.

[0067] Figure 8 yes Figure 7 Corresponding flow chart for determining the output signal of the first light signal and the output signal of the natural light signal.

[0068] Fig. 9 yes Figure 7 A schematic diagram of the angle of the corresponding first optical signal.

[0069] Fig.10 1 is a schematic diagram of a set of linear polarizers according to an embodiment of the present application, including a pixel unit array corresponding to three linear polarizers.

[0070] Fig.11 yes Fig.10 Corresponding flow chart for determining the output signal of the first light signal and the output signal of the natural light signal.

[0071] Fig.12 yes Fig.10 A schematic diagram of the angle of the corresponding first optical signal.

[0072] Fig.13 and Fig.14 yes Fig.10 Corresponding flow chart for determining the output signal of the first light signal and the output signal of the natural light signal.

[0073] Fig.15 1 is a schematic diagram of a set of linear polarizers according to an embodiment of the present application, including a pixel unit array corresponding to four linear polarizers.

[0074] Fig.16 yes Fig.15 Corresponding flow chart for determining the output signal of the first light signal and the output signal of the natural light signal.

[0075] Fig.17 yes Fig.15 A schematic diagram of the angle of the corresponding first optical signal.

[0076] Fig.18 and Fig.19 yes Fig.15 Corresponding flow chart for determining the output signal of the first light signal and the output signal of the natural light signal.

[0077] Fig. 20 It is a schematic block diagram of an electronic device according to an embodiment of the present application.

[0078] Fig.21 It is a schematic block diagram of a display screen according to an embodiment of the present application. DETAILED DESCRIPTION

[0079] The technical solution in this application will be described below in conjunction with the accompanying drawings.

[0080] With the continuous development of science and technology, fingerprint recognition technology is used in more and more electronic devices, among which under-display optical fingerprint recognition technology is the most widely used.

[0081] Combine the following Figure 1 and Figure 2The principle of the under-screen optical fingerprint recognition technology is briefly introduced. When the finger 110 presses the fingerprint recognition area on the display screen 120, the light source can send a light signal to the finger 110 above the fingerprint recognition area. Part of the light signal will propagate downward, which is called screen leakage light, and the other part of the light signal will go upward to form a screen outgoing light signal. The finger 110 will reflect the screen outgoing light signal to form a finger reflected light signal. The finger reflected light signal can be mainly divided into two parts: Figure 1 The light signal reflected from the finger surface shown in FIG. 1 (referred to as the reflected light signal for ease of description) and the light signal reflected from the finger surface shown in FIG. Figure 2 The light signal reflected from the inside of the finger is shown (referred to as the transmitted light signal for ease of description).

[0082] Continue to refer Figure 1 , because the fingerprint ridge is closely attached to the display screen 120 and has similar refractive index, the reflectivity of the light signal on optical path 2 is low. Because there is air between the fingerprint valley and the display screen 120, and the refractive index of the display screen 120 is greater than that of the air, the reflectivity of the light signal on optical path 1 is high. Specifically, assuming that the refractive index of the display screen 120 is 1.5, the refractive index of air is 1, and the refractive index of the finger 110 is 1.4, then the reflectivity of the fingerprint ridge point a is Reflectivity of fingerprint valley point b Reflectivity of fingerprint valley point c The total reflectivity of the fingerprint ridge is 0.12%, and the total reflectivity of the fingerprint valley is η b +η c =6.78%. Therefore, the reflected light signal of the fingerprint ridge is less, so dark lines can be formed, and the reflected light signal of the fingerprint valley is more, so bright lines can be formed.

[0083] and Figure 1 on the contrary, Figure 2 The transmittance of the optical signal at the fingerprint ridge is higher, while the transmittance of the optical signal at the fingerprint valley is lower. Assuming that the refractive index of the display screen 120 is 1.5, the refractive index of air is 1, and the refractive index of the finger 110 is 1.4, then Figure 2 Transmittance of point a at the middle fingerprint ridge The transmittance of point b in the fingerprint valley The transmittance of the fingerprint valley c point The total transmittance of the fingerprint ridge is 99.88%, and the total transmittance of the fingerprint valley is 93.33%. Therefore, the transmitted light signal of the fingerprint ridge is more, so it can form a bright pattern, and the reflected light signal of the fingerprint valley is less, so it can form a dark pattern.

[0084] Figure 1 The reflected light signal or Figure 2After the transmitted light signal passes through the optical layer in the fingerprint recognition device 130, it is received by the optical fingerprint sensor (also called optical fingerprint chip, sensor, sensor chip, chip, etc.) and converted into a corresponding electrical signal, i.e., a fingerprint recognition signal. Based on the fingerprint recognition signal, fingerprint image data can be obtained, and fingerprint matching verification can be further performed, thereby realizing the optical fingerprint recognition function in the electronic device.

[0085] The optical layer may include, but is not limited to, lenses, apertures, and filters. Among them, the lens can be used to converge light, for example, Figure 1 As shown, the reflected light signal reflected from the finger 110 is gathered to the fingerprint sensor below it. The aperture can be used to select light, and the filter can be used to filter out the light signal of the non-target band and transmit the light signal of the target band.

[0086] Of course, the fingerprint recognition device 130 can also be partially or completely integrated into the display screen 120 of the electronic device, thereby forming an in-display optical fingerprint system.

[0087] The light source mentioned above can be a display screen 120, that is, the display screen 120 is a display screen with a self-luminous display unit, such as an organic light-emitting diode (OLED) display screen, a micro-light-emitting diode (Micro-LED) display screen, or a mini-light-emitting diode (Mini-LED) display screen. Alternatively, the light source can also be an additional light source, that is, the optical fingerprint device 130 can use a built-in light source or an external light source to provide an optical signal for fingerprint recognition. In this case, the display screen 120 can be a non-self-luminous display screen, such as a liquid crystal display (LCD) or other passive light-emitting display screens.

[0088] The display screen 120 may include a cover plate 1201, a linear polarizer (Polarizer, PL) 1202, a quarter-wave plate (Quarter-Wave Plate) 1203, a sealing substrate 1204, a display pixel layer 1205, a back plate 1206 and other structures. Figure 3 As shown. Specifically, the cover plate can be a glass cover plate or a sapphire cover plate, which is arranged at the top of the display screen 120 and covers the front of the electronic device. Therefore, in the embodiment of the present application, the so-called finger 110 pressing on the display screen 120 actually means that the finger 110 presses the cover plate above the display screen 120. The display pixel layer can be used to emit light signals, the sealing substrate and the backplane are used to protect and carry the display pixel layer respectively, and the linear polarizer and the 1 / 4 wave plate can be used to form a circular polarizer, which is used to suppress the reflection of ambient light by the display screen 120.

[0089] Linear polarizers can convert ambient light or circularly polarized light into linearly polarized light, which allows light signals with vibration directions parallel to their polarization directions to pass through, while absorbing light signals with vibration directions perpendicular to the polarization directions. Among them, polarized light refers to light waves whose vibration directions of light vectors remain unchanged or have certain regular changes, linearly polarized light can refer to light waves whose light vectors vibrate only in a fixed direction, and circularly polarized light refers to polarized light whose two orthogonal components of the electric field vibration directions of the light waves differ in phase by 90° but have the same amplitude.

[0090] The linear polarizer can be any optical device used to produce linear polarized light. For example, the linear polarizer can be a thin layer formed by a material having a linear polarization function. For example, the linear polarizer can be composed of two pieces of optical glass sandwiching a piece of tiny polarizing crystal (such as mica) with a directional effect. In other alternative embodiments, the linear polarizer can also be replaced by a wire grid polarizer, which can be composed of many parallel metal wires placed in a plane. For example, a metal aluminum film is coated on a transparent grating with about 2160 lines per millimeter to form a transparent and reflective wire grid (i.e., a wire grid polarizer). The function of the wire grid polarizer is similar to that of the polarizer. When the ambient light passes through the wire grid, the polarized light parallel to the aluminum lines is absorbed and the polarized light perpendicular to the aluminum lines is passed. For example, the wire grid polarizer can be a crystal with a fence-like structure coated with a polyethylene film or polyvinyl cyanide in the interlayer between two pieces of optical glass. The crystal only allows light with the same vibration direction as the gap of the fence-like structure to pass.

[0091] It should be noted that the ambient light may include light of various polarization directions, that is, the light signal incident on the display screen 120 includes light signals of various polarization directions.

[0092] As subsequent screen display technology tends to be more self-luminous, non-self-luminous displays may be gradually eliminated. However, OLED displays also have disadvantages such as low brightness, short life, low efficiency, slow response speed, and low density. New display screens such as Micro-LED displays or Mini-LED displays can solve the above-mentioned shortcomings of OLED displays and may become the development direction of future displays. In addition, compared with OLED displays, Micro-LED displays or Mini-LED displays do not have layers such as polarizers and sealing plates, which can meet the terminal needs of lightweight and thinness.

[0093] In addition, during the fingerprint recognition process, the ambient light signal will affect the performance of fingerprint recognition. For example, as the external environment changes, the intensity of the ambient light signal will also change, thereby affecting the effect of fingerprint recognition. In addition, from the analysis of the reflectivity and transmittance of the aforementioned light signal, it can be seen that the reflected light signal at the fingerprint valley is stronger, so that the fingerprint image at the fingerprint valley is a white line, and the reflected light signal at the fingerprint ridge is weaker, so that the fingerprint image at the fingerprint ridge is a black line. On the contrary, the transmitted light signal at the fingerprint valley is weaker, so that the fingerprint image at the fingerprint valley is a black line, and the transmitted light signal at the fingerprint ridge is stronger, so that the fingerprint image at the fingerprint ridge is a white line. Therefore, the reflected light signal and the transmitted light signal will partially offset each other, that is, the transmitted light signal will affect the reflected light signal, thereby further affecting the fingerprint recognition performance.

[0094] Therefore, when there is no polarizer on the display screen, how to reduce the impact of ambient light signals and transmitted light signals on fingerprint recognition in order to improve fingerprint recognition performance is an urgent problem to be solved.

[0095] In view of this, an embodiment of the present application proposes a fingerprint recognition device, which can distinguish the reflected light signal and the transmitted light signal + ambient light signal through polarization difference, and can effectively reduce the influence of the ambient light signal and the transmitted light signal on fingerprint recognition, thereby improving the fingerprint recognition performance.

[0096] It should be noted that the fingerprint recognition device in the embodiment of the present application can also be called an optical fingerprint recognition module, an optical fingerprint device, a fingerprint recognition module, a fingerprint module, a fingerprint collection device, etc., and the above terms are interchangeable.

[0097] The following, combined Figures 4 to 19 , a fingerprint recognition device according to an embodiment of the present application is described in detail. It should be noted that, for ease of understanding, in the embodiments shown below, the same structures are denoted by the same reference numerals, and detailed descriptions of the same structures are omitted for brevity.

[0098] Figure 4 2 is a schematic structural diagram of a fingerprint recognition device 200 according to an embodiment of the present application. The fingerprint recognition device 200 can be applied to an electronic device including a display screen, and the display screen does not include a polarizing plate. Figure 4 As shown, the fingerprint recognition device 200 may include:

[0099] The linear polarizer array 210 includes a plurality of groups of linear polarizers, each group of the plurality of groups of linear polarizers includes at least two adjacent linear polarizers, and the polarization directions of the linear polarizers in each group of linear polarizers are different from each other;

[0100] The pixel unit array 220 is arranged below the linear polarizer array 210. The pixel unit array 220 includes multiple groups of pixel units. Each group of pixel units in the multiple groups of pixel units includes at least two pixel units and corresponds to a group of linear polarizers in the linear polarizer array. Each pixel unit in each group of pixel units is used to receive a light signal. The light signal may include a first light signal 2201 in which the linear polarized light signal emitted by the light source passes through the surface of the finger above the display screen and returns, a second light signal 2202 in which the linear polarized light signal emitted by the light source passes through the inside of the finger above the display screen and returns, and an ambient light signal 2203. The pixel values ​​of at least two pixel units in each group of pixel units are used to obtain a fingerprint image.

[0101] The first optical signal 2201 is a linearly polarized optical signal, and the second optical signal 2202 and the ambient light signal 2203 are natural light signals (for the convenience of the following description, the second optical signal and the ambient light signal are collectively referred to as natural light signals).

[0102] Optionally, the polarization directions of two adjacent linear polarizers in the linear polarizer array 210 may be different. The characteristics of the linear polarizer may refer to the linear polarizer described in the foregoing content, which may be an independent linear polarizer structure, or a linear polarizer film or other structure with linear polarization function. The pixel unit may use devices such as a photodiode (PD), a metal oxide semiconductor field effect transistor (MOSFET), etc.

[0103] In the embodiment of the present application, under the condition that the display screen does not have a polarizing plate, the fingerprint recognition device includes a linear polarizing plate array, and the light source emits a linearly polarized light signal, so that the first light signal returned through the finger surface is a linearly polarized light signal, the second light signal returned through the inside of the finger is a natural light signal, and the ambient light signal is also a natural light signal, so that the first light signal returned through the finger surface can be distinguished from the natural light signal by polarization difference, so that the second light signal can avoid the situation where the first light signal is offset, thereby effectively enhancing the fingerprint signal. In addition, the embodiment of the present application can also reduce the influence of the natural light signal on fingerprint recognition, thereby further improving the fingerprint recognition performance.

[0104] from Figure 4 As can be seen in FIG, the display screen 120 includes a cover plate 1201, a surface optical layer 1207, a display pixel layer 1205, a back plate 1206 and other structures from top to bottom, and does not have a linear polarizer and a quarter wave plate. Among them, the surface optical layer 1207 can be used to protect the display pixel layer 1205 and can be used for anti-glare. The display pixel layer 1205 includes a display pixel array formed by a plurality of display pixels, and the display pixels can provide a light source for displaying images.

[0105] Figure 4 The fingerprint recognition device 200 is arranged below the display screen 120. In the embodiment of the present application, the fingerprint recognition device 200 may also be arranged inside the display screen 120. Figure 5 As shown, the fingerprint recognition device 200 is arranged in the display screen 120. In this case, in addition to the cover plate 1201, the surface optical layer 1207, the display pixel layer 1205 and the back plate 1206 and other structures, the display screen 120 may also include a photosensitive layer 1208. The photosensitive layer 1208 may include the fingerprint recognition device 200, the optical layer and the driving circuit and other structures.

[0106] Optionally, the photosensitive layer 1208 may be disposed above the display pixel layer 1205 . This configuration may reduce interference from other optical signals (such as light leakage).

[0107] Alternatively, the photosensitive layer 1208 may be Figure 5 As shown, the display pixel layer 1205 is arranged on the same layer, so that the driving circuit of the display screen 120 and the driving circuit of the fingerprint recognition device 200 can be manufactured together, thereby reducing the manufacturing complexity of the display screen 120. In order to reduce the interference of other light signals to the first light signal, a light blocking layer can be arranged around the pixel unit array 220 or other structures to block the interference of other light signals.

[0108] Of course, the photosensitive layer 1208 can also be disposed below the display pixel layer 1205 .

[0109] Figure 4 and Figure 5 The light source of the fingerprint recognition device 200 shown is at least part of the display pixels of the display screen 120, that is, the display screen 120 is a display screen with self-luminous display pixels (display units), and the display screen 120 can emit linearly polarized light signals. Optionally, the display screen 120 can be a Micro-LED display screen or a Mini-LED display screen.

[0110] In other implementations, such as Figure 6 As shown, the light source may also be an external light source 230, which may emit a linearly polarized light signal. The external light source 230 may be, but is not limited to, an infrared LED lamp, which may be disposed below the display screen 120 and may be separated from the fingerprint recognition device 200.

[0111] It should be noted that the embodiments of the present application do not specifically limit the implementation method of the light source emitting a linearly polarized light signal, and any implementation method that can enable the light source to emit a linearly polarized light signal can be included in the scope of the embodiments of the present application.

[0112] Optionally, in the embodiment of the present application, the angle of the linearly polarized light signal may be preset.

[0113] Optionally, in an embodiment of the present application, the linear polarizer array 210 can be arranged at any position in the light path between the display screen 120 and the pixel unit array 220. For example, the linear polarizer array 210 can be arranged on the lower surface of the display screen 120. For another example, the linear polarizer array 210 can be arranged between the display screen 120 and the pixel unit array 220 by a fixing device, and the fixing device can include but is not limited to a bracket, a glue layer, etc. For another example, the linear polarizer array 210 can also be integrated with the pixel unit array 220 in the chip of the optical fingerprint sensor. Specifically, the linear polarizer array 210 can be formed by coating the pixel unit array 220 with an evaporation process. For example, a polarizing film can be prepared above the pixel unit array 220 by atomic layer deposition, sputtering coating, electron beam evaporation coating, ion beam coating, etc. Alternatively, a complementary metal oxide semiconductor (CMOS) process may be used to prepare a plurality of metal wire grid micro polarizers as polarization units on the pixel unit array 220. The metal wire grid micro polarizer structure is a periodic metal wire grid array, wherein the width and spacing of the metal wire grid are tens to hundreds of nanometers.

[0114] The embodiment of the present application does not specifically limit the number of linear polarizers included in each group of linear polarizers and the number of pixel units included in each group of pixel units. Figure 4 As shown, the linear polarizer array 210 includes a first linear polarizer group 211, and the pixel unit array 220 includes a first pixel unit group 221. The linear polarizer group 211 corresponds to the pixel unit group 221. The linear polarizer group 211 includes two linear polarizers, and the polarization directions of the two linear polarizers are different, and the pixel unit group 221 includes two pixel units. Of course, each group of linear polarizers can also include three linear polarizers, and the polarization directions of the three linear polarizers are different, and each group of pixel units can also include three pixel units; or, each group of linear polarizers can also include four linear polarizers and each group of pixel units can also include four pixel units, etc.

[0115] The number of linear polarizers included in different groups of linear polarizers in the linear polarizer array 210 may be the same or different. For example, the number of linear polarizers included in each group of linear polarizers may be 2. For another example, the linear polarizer group 211 includes 2 linear polarizers, and the other linear polarizer groups include 3 or 4 linear polarizers.

[0116] Similar to the linear polarizer array 210 , the numbers of pixel units included in different groups of pixel units in the pixel unit array 220 may be the same or different.

[0117] Optionally, in the embodiment of the present application, the absolute value of the difference between the output signals of at least two pixel units in each group of pixel units can be used to determine the output signal of the group of pixel units to the first light signal, wherein the output signal of the first light signal is used to obtain the fingerprint image. Further, the output signals of the pixel units in each group of pixel units and the output signals of the group of pixel units to the first light signal can also be used to determine the output signal of the natural light signal.

[0118] The output signal of the pixel unit is in a linear relationship with the light intensity of the pixel unit. Specifically, the output signal of the pixel unit is in a proportional relationship with the light intensity of the pixel unit.

[0119] In order to more clearly describe the scheme of the embodiments of the present application, the embodiments of the present application are described below by taking the example that each group of linear polarizers includes 2 linear polarizers, 3 linear polarizers or 4 linear polarizers, but it should be understood that the present application is not limited to this.

[0120] Embodiment 1: Each set of linear polarizers includes 2 linear polarizers

[0121] The polarization directions of the two linear polarizers may be at any angle to each other. Optionally, the polarization directions of the two linear polarizers may be perpendicular to each other. For example, Figure 7 A top view of the pixel unit array 220 is shown. Figure 7 It can be seen that in a group of linear polarizers corresponding to a group of pixel units, the polarization direction of one of the linear polarizers is 0°, and the polarization direction of the other linear polarizer is 90°.

[0122] In this case, the absolute value of the difference between the output signals of two pixel units in a group of pixel units can be used to determine the output signal of the group of pixel units to the first light signal, and the output signals of the two pixel units in a group of pixel units and the output signal of the first light signal can be used to determine the output signal of the group of pixel units to the natural light signal.

[0123] Taking the pixel unit group 221 as an example, the pixel unit group 221 includes a pixel unit U and a pixel unit V. The light signals received by the pixel unit U and the pixel unit V include a first light signal and a natural light signal. Figure 8 As shown, the output signals LI of the adjacent pixel units U and V can be obtained first. U and LI V Then, the output signal LI of the pixel unit U U and the output signal LI of the pixel unit V V The difference or the absolute value of the difference can be the output signal LI of the first optical signal. OP Furthermore, the output signal LI of the pixel unit U can be used to U, the output signal LI of the pixel unit V V and the output signal LI of the first optical signal OP , determine the output signal LI of the natural light signal ON Among them, LI ON =LI U +LI V -LI OP .

[0124] Combination Fig. 9 For example, it should be noted that in order to compare the signal-to-noise ratio of different data processing methods under different linear polarizer applications, the embodiment of the present application also calculates the noise signal of the first light signal and the noise signal of the natural light signal. Assume that the angle of the first light signal is α, α∈[0,π], and the output signal is LI P , the photon noise is N P , the output signal of natural light signal is LI N , the photon noise is N N .

[0125] The output signal LI of the pixel unit U U and photon noise N U They are:

[0126]

[0127]

[0128] The output signal LI of the pixel unit V V and photon noise N V They are:

[0129]

[0130]

[0131] The output signal LI of the pixel unit group 211 can be obtained by summing the pixel value of the pixel unit U and the pixel value of the pixel unit V. U+V and the noise signal N of the pixel unit group 211 U+V :

[0132] LI U+V =LI U +LI V =LI P +LI N

[0133]

[0134] The pixel value of pixel unit U is subtracted from the pixel value of pixel unit V to eliminate the natural light signal, and the first light signal remains. The output signal LI of the first light signal is OP and the noise signal N OP They can be:

[0135] LI OP =LI U-V =LI U -LI V =LI P *cos(2α)

[0136]

[0137] Of course, the output signal LI of the first optical signal OP It can also be the output signal LI of the pixel unit V V Subtract the output signal LI of the pixel unit U U The value of .

[0138] It can be seen from the above formula that when α=0 or α=π / 2, that is, the polarization direction of the first light signal is parallel to the polarization direction of one of the linear polarizers corresponding to the pixel unit U and the pixel unit V, the output signal LI of the first light signal is OP Maximum, (LI OP ) max =LI P .

[0139] At this time, the output signal LI of the natural light signal ON and the noise signal N ON They can be:

[0140] LI ON =LI U+V -LI OP =LI N

[0141]

[0142] Specifically, when α=0, the output signal LI of the natural light signal ON and the noise signal N ON They are:

[0143] LI ON =2*LI V =LI N

[0144]

[0145] When α=π / 2, the output signal LI of the natural light signal ON and the noise signal NON They are:

[0146] LI ON =2*LI V =LI N

[0147]

[0148] Embodiment 2: Each set of linear polarizers includes 3 linear polarizers

[0149] The polarization directions of the three linear polarizers may be at any angle. Optionally, Fig.10 A top view of the pixel unit array 220 is shown. Fig.10 As can be seen from the figure, a group of linear polarizers corresponding to a group of pixel units may include a linear polarizer with a step of 60°. For example, a group of linear polarizers may include three linear polarizers with polarization directions of 0°, 60° and 120°, respectively.

[0150] In this case, the absolute value of the difference between the output signals of at least two pixel units in a group of pixel units can be used to determine the output signal of the group of pixel units to the first light signal. In addition, the output signal of each pixel unit in a group of pixel units and the output signal of the group of pixel units to the first light signal can be used to determine the output signal of the natural light signal.

[0151] Taking the pixel unit group 221 as an example, the pixel unit group 221 includes a pixel unit X, a pixel unit Y and a pixel unit Z. In one implementation, the absolute value of the difference between the output signals of any two pixel units in the pixel unit group 221 can be used as the output signal LI of the first light signal. OP In addition, the output signal LI of the pixel unit X X , the output signal LI of the pixel unit Y Y and the output signal LI of the pixel unit Z Z and an output signal LI of the first optical signal OP It can also be used to determine the output signal LI of the natural light signal ON .

[0152] For example, Fig.11 As shown, the output signal LI of the adjacent pixel unit X can be obtained first. X , the output signal LI of the pixel unit Y Y and the output signal LI of the pixel unit Z Z , then the output signal LI of pixel unit X X and the output signal LI of the pixel unit Y Y The absolute value of the difference can be the output signal LI of the first optical signal.OP Furthermore, the output signal LI of the pixel unit X can be X , the output signal LI of the pixel unit Y Y and the output signal LI of the pixel unit Z Z and the output signal LI of the first optical signal OP , determine the output signal LI of the natural light signal ON .in,

[0153] Combination Fig.12 For example, assuming that the angle of the first optical signal is α, α∈[0,π], and the output signal is LI P , the photon noise is N P , the output signal of natural light signal is LI N , the photon noise is N N .

[0154] The output signal LI of pixel unit X X and photon noise N X They are:

[0155]

[0156]

[0157] The output signal LI of the pixel unit Y Y and photon noise N Y They are:

[0158]

[0159]

[0160] The output signal LI of the pixel unit Z Z and photon noise N Z They are:

[0161]

[0162]

[0163] The output signal LI of the pixel unit group 211 can be obtained by summing the pixel value of the pixel unit X, the pixel value of the pixel unit Y and the pixel value of the pixel unit Z and dividing it by 3 / 2. X+Y+Z and the noise signal N X+Y+Z :

[0164]

[0165]

[0166] The output signal LI of the pixel unit X X and the output signal LI of the pixel unit Y Y The difference between X-Y The output signal LI as the first optical signal OP , and the photon noise N of pixel unit X X and the photon noise N of pixel unit Y Y The difference between X-Y The noise signal N as the first optical signal OP ,Right now:

[0167]

[0168]

[0169] It can be seen that when α=5π / 12 or α=11π / 12, the output signal LI of the first optical signal OP maximum,

[0170] At this time, the output signal LI of the natural light signal ON and the noise signal N ON They can be:

[0171]

[0172]

[0173] Of course, the output signal LI of the pixel unit Y Y The output signal LI of the pixel unit Z Z The difference between Y-Z It can also be used as the output signal LI of the first optical signal OP , the photon noise N of pixel unit Y Y and the photon noise N of pixel unit Z Z The difference between Y-Z Also known as the noise signal N of the first optical signal OP Or, the output signal LI of the pixel unit Z Z The output signal LI of the pixel unit X X The difference between Z-X It can also be used as the output signal LI of the first optical signal OP , the photon noise N of pixel unit Z Z and the photon noise N of pixel unit X X The difference between Z-X Also known as the noise signal N of the first optical signal OP .

[0174] In another implementation, the difference between the output signals of the three pixel units in the pixel unit group 221 can be used to determine the output signal LI of the first light signal. OP .

[0175] As an example, Fig.13 As shown, LI X-Y , LI Y-Z and LI Z-X The squares of the first optical signal are added and then squared to obtain the output signal LI of the first optical signal. OP :

[0176]

[0177] And, N X-Y 、N Y-Z and N Z-X The square of the first optical signal is added and then squared to obtain the noise signal N OP :

[0178]

[0179] At this point, continue to refer to Fig.13 , the output signal LI of the natural light signal ON and the noise signal N ON They can be:

[0180]

[0181]

[0182] As another example, Fig.14 As shown, LI X-Y , LI Y-Z and LI Z-X The absolute values ​​are taken respectively and then added to obtain the output signal LI of the first optical signal OP :

[0183]

[0184] At the same time, N X-Y 、N Y-Z and N Z-X The squares of the first optical signal are added and then squared to obtain the noise signal N of the first optical signal. OP :

[0185]

[0186] It can be seen that when α=π / 12 or α=3π / 12 or α=5π / 12 or α=7π / 12 or α=9π / 12 or α=11π / 12, the output signal LI of the first optical signal is OP maximum,

[0187] In this example, continue to refer to Fig.14 , the output signal LI of the natural light signal ON and the noise signal N ON They can be:

[0188]

[0189]

[0190] Embodiment 3: Each set of linear polarizers includes 4 linear polarizers

[0191] The polarization directions of the four linear polarizers may be at any angle. Optionally, Fig.15 A top view of the pixel unit array 220 is shown. Fig.15 As can be seen from the figure, a group of linear polarizers corresponding to a group of pixel units may include linear polarizers with a step of 45°. For example, a group of linear polarizers may include four linear polarizers with polarization directions of 0°, 45°, 90° and 135°, respectively.

[0192] In this case, the absolute value of the difference between the output signals of at least two pixel units in a group of pixel units can be used to determine the output signal of the group of pixel units to the processed first light signal. In addition, the output signal of each pixel unit in a group of pixel units and the output signal of the group of pixel units to the first light signal can be used to determine the output signal of the natural light signal.

[0193] Taking the pixel unit group 221 as an example, the pixel unit group 221 includes pixel unit A, pixel unit B, pixel unit C and pixel unit D. Among them, the polarization direction of the linear polarizer corresponding to the pixel unit A is perpendicular to the polarization direction of the linear polarizer corresponding to the pixel unit C, and the polarization direction of the linear polarizer corresponding to the pixel unit B is perpendicular to the polarization direction of the linear polarizer corresponding to the pixel unit D. For example, the polarization direction of the polarizer corresponding to the pixel unit A is 0°, the polarization direction of the polarizer corresponding to the pixel unit B is 45°, the polarization direction of the polarizer corresponding to the pixel unit C is 90°, and the polarization direction of the polarizer corresponding to the pixel unit D is 135°. However, it should be understood that the polarization directions of the linear polarizers corresponding to the pixel units A, B, C and D are not limited to this example.

[0194] It should be noted that Fig.15The arrangement of the pixel units shown is only an example and should not be construed as limiting the embodiments of the present application. For example, pixel unit A and pixel unit C may also be arranged adjacent to each other, and pixel unit C may be arranged at Fig.15 The position of pixel unit D or the position of pixel unit B is shown.

[0195] In one implementation, the absolute value of the difference between the output signals of any two pixel units in the pixel unit group 221 can be used as the output signal LI of the first light signal. OP .

[0196] For example, Fig.16 As shown, the output signal LI of the adjacent pixel unit A can be obtained first. A , the output signal LI of the pixel unit B B , the output signal LI of the pixel unit C C and the output signal LI of the pixel unit D D , then the output signal LI of pixel unit A A and the output signal LI of pixel unit B B The absolute value of the difference can be the output signal LI of the first optical signal. OP Furthermore, the output signal LI of the pixel unit A can be used to A , the output signal LI of the pixel unit B B , the output signal LI of the pixel unit C C , the output signal LI of the pixel unit D D and the output signal LI of the first optical signal OP , determine the output signal LI of the natural light signal ON Among them, LI ON =LI A +LI B +LI C +LI D -LI OP .

[0197] Of course, the output signal LI of the pixel unit B can also be B and the output signal LI of the pixel unit D D Make a difference and take the absolute value of the difference, then the absolute value of the difference can be LI OP .

[0198] Since the direction of the linear polarizer corresponding to pixel unit A is perpendicular to the polarization direction of the linear polarizer corresponding to pixel unit C, and the direction of the linear polarizer corresponding to pixel unit B is perpendicular to the polarization direction of the linear polarizer corresponding to pixel unit D, the absolute value of the difference between the output signal of pixel unit A and the output signal of pixel unit C is taken as LI OPAlternatively, the absolute value of the difference between the output signal of pixel unit B and the output signal of pixel unit D is taken as LI OP The amount of calculation is minimized, which can reduce the time consumption of the fingerprint recognition process and thus improve the efficiency of fingerprint recognition.

[0199] Combination Fig.17 For example, assuming that the angle of the first optical signal is α, α∈[0,π], and the output signal is LI P , the photon noise is N P , the output signal of natural light signal is LI N , the photon noise is N N .

[0200] The output signal LI of pixel unit A A and photon noise N A They are:

[0201]

[0202]

[0203] The output signal LI of pixel unit B B and photon noise N B They are:

[0204]

[0205]

[0206] The output signal LI of the pixel unit C C and photon noise N C They are:

[0207]

[0208]

[0209] The output signal LI of the pixel unit D D and photon noise N D They are:

[0210]

[0211]

[0212] The pixel value of pixel unit A and the pixel value of pixel unit C are subtracted to obtain the output signal LI A-C and the noise signal N A-C :

[0213] LI A-C =LIA -LI C =LI P *cos(2α)

[0214]

[0215] The pixel value of pixel unit B and the pixel value of pixel unit D are subtracted to obtain the output signal LI B-D and the noise signal N B-D :

[0216] LI B-D =LI B -LI D =LI P *sin(2α)

[0217]

[0218] The output signal LI of the pixel unit group 211 can be obtained by summing the pixel values ​​of the pixel unit A, the pixel value of the pixel unit B, the pixel value of the pixel unit C and the pixel value of the pixel unit D and dividing by 2. A+B+C+D and the noise signal N A+B+C+D :

[0219]

[0220]

[0221] The output signal LI of the pixel unit A A and the output signal LI of the pixel unit C C The difference between A-C The output signal LI as the first optical signal OP , and the photon noise N of pixel unit A A and the photon noise N of pixel unit C C The difference between A-C The noise signal N as the first optical signal OP ,Right now:

[0222] LI OP =LI A-C =LI P *cos(2α)

[0223]

[0224] It can be seen that when α=0 or α=π / 2, the output signal LI of the first optical signal OP Maximum, (LI OP ) max =LI P .

[0225] At this time, the output signal LI of the natural light signal ON and the noise signal N ON They can be:

[0226] LI ON =LI A+B+C+D -LI OP =LI N

[0227]

[0228] Specifically, when α=0, the output signal LI of the natural light signal ON and the noise signal N ON They can be:

[0229] LI ON =2*LI C =LI N

[0230]

[0231] When α=π / 2, the output signal LI of the natural light signal ON and the noise signal N ON They can be:

[0232] LI ON =2*LI A =LI N

[0233]

[0234] Of course, the output signal LI of the pixel unit B B The output signal LI of the pixel unit D D The difference between B-D It can also be used as the output signal LI of the first optical signal OP , the photon noise N of pixel unit B B and the photon noise N of pixel unit D D The difference between B-D Also known as the noise signal N of the first optical signal OP .

[0235] In another implementation, the difference between the output signals of two pairs of any two pixel units can be used to determine the output signal LI of the first light signal. OP For example, the output signal LI of pixel unit A is A and the output signal LI of the pixel unit C C The difference between A-C , and the output signal LI of the pixel unit BB The output signal LI of the pixel unit D D The difference between B-D The output signal LI of the first optical signal can be used to determine OP .

[0236] As an example, Fig.18 As shown, LI A-C and LI B-D The square root of the square sum is taken to obtain the output signal LI of the first optical signal OP :

[0237]

[0238] N A-C and N B-D The noise signal N of the first optical signal can be obtained by taking the square root of the square sum of OP :

[0239]

[0240] At this point, continue to refer to Fig.18 , the output signal LI of the natural light signal ON and the noise signal N ON They can be:

[0241] LI ON =LI A+B+C+D -LI OP =LI N

[0242]

[0243] As another example, Fig.19 As shown, LI A-C and LI B-D After taking the absolute values ​​respectively and then adding them together, the output signal LI of the first optical signal can be obtained. OP :

[0244]

[0245] And, N A-C and N B-D The square root of the square sum of the first optical signal is obtained by OP :

[0246]

[0247] It can be seen that when α=π / 8 or α=3π / 8 or α=5π / 8 or α=7π / 8, the output signal LI of the first optical signal is OP maximum,

[0248] In this example, continue to refer to Fig.19 , the output signal LI of the natural light signal ON and the noise signal N ON They can be:

[0249]

[0250]

[0251] It should be understood that the specific examples in the embodiments of the present application are only intended to help those skilled in the art to better understand the embodiments of the present application, rather than to limit the scope of the embodiments of the present application.

[0252] The above content describes the conditions under which each set of linear polarizers includes 2 linear polarizers, 3 linear polarizers, and 4 linear polarizers to obtain the output signal LI of the first light signal. OP , the noise signal N of the first optical signal OP , output signal LI of natural light signal ON And the noise signal N of the natural light signal ON The following will compare the application of different polarizers described above under the same conditions with 12 pixel units as a period.

[0253] (1) When the fingerprint recognition device 200 does not include the linear polarizer array 210, the output signal of each pixel unit is (LI P +LI N ), the output noise signal is Taking the average of the pixel values ​​of the 12 pixel units, it can be seen that the average output signal of each pixel unit remains unchanged, and the average output noise is

[0254] Furthermore, when the fingerprint recognition device 200 does not include the linear polarizer array 210 , the first light signal and the natural light signal cannot be distinguished.

[0255] (2) When the fingerprint recognition device 200 includes a linear polarizer array 210, and each group of linear polarizers includes two linear polarizers whose polarization directions are perpendicular to each other, the 12 pixel units can be divided into 6 groups.

[0256] Each group of pixel units outputs a signal LI for the processed first light signal OP =LI P *cos(2α), noise signal After the output signals of the first light signals of the six adjacent pixel unit groups are averaged, the average output signal LI of the first light signal is OP ' and the average noise signal NOP 'Respectively:

[0257]

[0258]

[0259] Each group of pixel units outputs a signal LI for the processed natural light signal ON =LI N , noise signal After averaging the output signals of the natural light signals of the six adjacent pixel unit groups, the average output signal LI of the natural light signal is ON ' and the average noise signal N ON 'Respectively:

[0260]

[0261]

[0262] Of course, it can also be processed in a special way, that is, when α=0 or α=π / 2, the output signal LI of each group of pixel units for the processed natural light signal is ON =LI N , noise signal After averaging the output signals of the natural light signals of the six adjacent pixel unit groups, the average output signal LI of the natural light signal is ON '=LI N , the average noise signal of the natural light signal

[0263] (3) When the fingerprint recognition device 200 includes a linear polarizer array 210, and each group of linear polarizers includes three linear polarizers whose polarization directions are perpendicular to each other, the 12 pixel units can be divided into four groups.

[0264] a. Output signal of each group of pixel units for the processed first light signal Noise signal After averaging the output signals of the first light signals of the four adjacent pixel unit groups, the average output signal LI of the first light signal can be obtained by using the calculation method described above. OP '=LI OP , the average noise signal of the first optical signal

[0265] Each group of pixel units outputs a signal LI for the processed natural light signal ON =LI N , noise signal After the output signals of the natural light signals of the four adjacent pixel unit groups are averaged, the average output signal LI of the natural light signal is ON'=LI N , the average noise signal of the natural light signal

[0266] b. Output signal of each group of pixel units for the processed first light signal Noise signal After the output signals of the first light signals of the four adjacent pixel unit groups are averaged, the average output signal LI of the first light signal is OP '=LI OP , the average noise signal of the first optical signal

[0267] Each group of pixel units outputs a signal LI for the processed natural light signal ON =LI N , noise signal After the output signals of the natural light signals of the four adjacent pixel unit groups are averaged, the average output signal LI of the natural light signal is ON '=LI N , the average noise signal of the natural light signal

[0268] c. The maximum output signal of each group of pixel units after processing the first light signal Minimum output signal (LI OP ) min =1.5*LI P , noise signal N OP = After the output signals of the first light signals of the four adjacent pixel unit groups are averaged, the average output signal LI of the first light signal is OP '=LI OP , the average noise signal of the first optical signal

[0269] Each group of pixel units outputs a signal LI for the processed natural light signal ON =LI N , noise signal After the output signals of the natural light signals of the four adjacent pixel unit groups are averaged, the average output signal LI of the natural light signal is ON '=LI N , the average noise signal of the natural light signal

[0270] (4) When the fingerprint recognition device 200 includes a linear polarizer array 210, and each group of linear polarizers includes four linear polarizers whose polarization directions are perpendicular to each other, the 12 pixel units can be divided into three groups.

[0271] a. Output signal LI of each group of pixel units for the processed first light signalOP =LI P *cos(2α), noise signal After the output signals of the first light signals of the three adjacent pixel unit groups are averaged, the average output signal LI of the first light signal is OP '=LI OP , the average noise signal of the first optical signal

[0272] Each group of pixel units outputs a signal LI for the processed natural light signal ON =LI N , noise signal After the output signals of the natural light signals of the three adjacent pixel unit groups are averaged, the average output signal LI of the natural light signal is ON '=LI N , the average noise signal of the natural light signal

[0273] It can also be processed in a special way, that is, when α = 0 or α = π / 2, the output signal LI of the natural light signal ON =LI N , noise signal After the output signals of the natural light signals of the three adjacent pixel unit groups are averaged, the average output signal LI of the natural light signal is ON '=LI N , the average noise signal of the natural light signal

[0274] b. Output signal LI of each pixel unit group after processing the first light signal OP =LI P , noise signal After the output signals of the first light signals of the three adjacent pixel unit groups are averaged, the average output signal LI of the first light signal is OP '=LI OP , the average noise signal of the first optical signal

[0275] Each group of pixel units outputs a signal LI for the processed natural light signal ON =LI N , noise signal After the output signals of the natural light signals of the three adjacent pixel unit groups are averaged, the average output signal LI of the natural light signal is ON '=LI N , the average noise signal of the natural light signal

[0276] c. The maximum output signal of each group of pixel units after processing the first light signal Minimum output signal (LI OP ) min =LI P , noise signal After the output signals of the first light signals of the three adjacent pixel unit groups are averaged, the average output signal LI of the first light signal is OP '=LI OP , the average noise signal of the first optical signal

[0277] Each group of pixel units outputs a signal LI for the processed natural light signal ON =LI N , noise signal After the output signals of the natural light signals of the three adjacent pixel unit groups are averaged, the average output signal LI of the natural light signal is ON '=LI N , the average noise signal of the natural light signal

[0278] Further, Table 1 shows the parameter comparison of the first light signal under different linear polarizer applications, and Table 2 shows the parameter comparison of the natural light signal under different linear polarizer applications. In Tables 1 and 2, the two-way linear polarizer means that a group of linear polarizers includes two linear polarizers, the three-way linear polarizer includes a group of linear polarizers including three linear polarizers, and the four-way linear polarizer includes a group of linear polarizers including four linear polarizers.

[0279] Table 1

[0280]

[0281] The “insensitive” in the polarization direction sensitivity in Table 1 indicates that the output signal of the first optical signal has nothing to do with α. For example, in the case of the three-directional polarizer method b, the output signal of the first optical signal is It can be seen that the output signal LI of the first optical signal OP It has nothing to do with α.

[0282] The “strong sensitivity” in the polarization direction sensitivity in Table 1 indicates that the output signal of the first optical signal is related to α, and the signal-to-noise ratio may drop to 0. For example, in the case of a two-directional polarizer, the output signal LI of the first optical signal is OP =LI P *cos(2α), it can be seen that the output signal LI of the first optical signal OP is related to α, and when α=π / 4, LI OP =0, the signal-to-noise ratio is 0.

[0283] The “weak sensitivity” in the polarization direction sensitivity in Table 1 indicates that the output signal of the first optical signal is related to α, and the signal-to-noise ratio will not drop significantly, that is, the signal-to-noise ratio will not drop to zero.

[0284] Table 2

[0285]

[0286]

[0287] It can be seen that providing the linear polarizer array 210 in the fingerprint recognition device 200 can eliminate the influence of the natural light signal on the fingerprint recognition performance.

[0288] Optionally, in the embodiment of the present application, the fingerprint recognition device 200 may further include a processing unit 240, which may be used to determine the output signal LI of the first light signal mentioned above. OP , the noise signal N of the first optical signal OP , output signal LI of natural light signal ON And the noise signal N of the natural light signal ON .

[0289] The processing unit 240 may be a central processing unit (CPU), or other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field-programmable gate arrays (FPGAs) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor may be a microprocessor or any conventional processor, etc.

[0290] Optionally, in the embodiment of the present application, the fingerprint recognition device 200 may further include: an optical component, arranged between the display screen 120 and the pixel unit array 220, for guiding or converging the light signal to the pixel unit array 220 when the object to be recognized presses the fingerprint recognition area of ​​the display screen 120.

[0291] The optical component may include at least one aperture layer and a microlens array. At least one aperture layer is provided with a plurality of light-transmitting pinholes, and the microlens array is provided above at least one aperture layer, and is used to converge the first light signal, the second light signal, and the ambient light signal to the plurality of light-transmitting pinholes of at least one aperture layer when the object to be identified is pressed on the display screen 120, and the first light signal, the second light signal, and the ambient light signal are transmitted to the pixel unit array 220 through the plurality of light-transmitting pinholes of at least one aperture layer.

[0292] The at least one aperture layer can be formed on the pixel unit array 220 by semiconductor process growth or other processes. For example, a non-light-transmitting material film is prepared on the pixel unit array 220 by atomic layer deposition, sputtering coating, electron beam evaporation coating, ion beam coating, etc., and then the aperture pattern is photolithographically and etched to form a plurality of light-transmitting apertures. The at least one aperture layer can block the optical interference between adjacent microlenses, and make the light signal corresponding to the pixel unit converge into the light-transmitting aperture through the microlens and be transmitted to the pixel unit through the light-transmitting aperture to perform optical fingerprint imaging.

[0293] The microlens array is formed by a plurality of microlenses, which can be formed above at least one aperture layer by a semiconductor growth process or other processes, and each microlens can correspond to one of the pixel units of the pixel unit array 220.

[0294] It should be understood that the optical component can be disposed at any position in the light path between the display screen 120 and the pixel unit array 220 , for example, between the pixel unit array 220 and the linear polarizer array 210 .

[0295] The present application also provides an electronic device, such as Fig. 20 As shown, the electronic device 300 may include a display screen 310 and a fingerprint recognition device 320. The fingerprint recognition device 320 may be the fingerprint recognition device in the aforementioned embodiment, and is disposed below the display screen 310 or inside the display screen 310.

[0296] It should be understood that the display screen 310 may be a non-folding display screen or a foldable display screen, that is, a flexible display screen.

[0297] As an example but not limitation, the electronic device in the embodiment of the present application can be a portable or mobile computing device such as a terminal device, a mobile phone, a tablet computer, a laptop computer, a desktop computer, a gaming device, an in-vehicle electronic device or a wearable smart device, as well as other electronic devices such as an electronic database, a car, and an automated teller machine (ATM). The wearable smart device includes a full-featured, large-size, and can realize complete or partial functions without relying on a smart phone, such as a smart watch or smart glasses, etc., and only focuses on a certain type of application function and needs to be used in conjunction with other devices such as a smart phone, such as various smart bracelets and smart jewelry for vital sign monitoring.

[0298] The electronic device 300 may further include a circuit board, which is disposed below the fingerprint recognition device 320. The fingerprint recognition device 320 may be bonded to the circuit board by adhesive, and electrically connected to the circuit board by soldering pads and metal wires. The fingerprint recognition device 320 may be electrically interconnected and transmit signals with other peripheral circuits or other components of the electronic device 300 through the circuit board. For example, the fingerprint recognition device 320 may receive a control signal of a processing unit of the electronic device 300 through the circuit board, and may also output a fingerprint detection signal from the fingerprint recognition device 320 to a processing unit or control unit of the terminal device through the circuit board.

[0299] The present application also provides a display screen, such as Fig.21 As shown, the display screen 400 may include a display pixel layer 410 and a fingerprint recognition device 420, and the fingerprint recognition device 420 may be the fingerprint recognition device in the aforementioned embodiment. The display pixel layer 410 may include a display pixel array formed by a plurality of display pixels. The display screen 400 may emit linearly polarized light, that is, the display pixels may emit linearly polarized light, and at least part of the display pixels of the display screen 400 may be used as a light source of the fingerprint recognition device 420 for fingerprint recognition.

[0300] The fingerprint recognition device 420 may be disposed above or below the display pixel layer 410 , or the fingerprint recognition device 420 and the display pixel layer 410 may be disposed on the same layer.

[0301] Furthermore, the display screen 400 may also include a cover plate, a surface optical layer, and a back plate. The specific arrangement of the cover plate, the surface optical layer, and the back plate in the display screen 400 may refer to Figure 5 For the sake of brevity, I will not go into details here.

[0302] It should be noted that, under the premise of no conflict, the various embodiments described in this application and / or the technical features in each embodiment can be arbitrarily combined with each other, and the technical solution obtained after the combination should also fall within the protection scope of this application.

[0303] It should be understood that the terms used in the embodiments of the present application and the appended claims are only for the purpose of describing specific embodiments, and are not intended to limit the embodiments of the present application. For example, the singular forms "a", "above", and "the" used in the embodiments of the present application and the appended claims are also intended to include plural forms, unless the context clearly indicates other meanings.

[0304] Those of ordinary skill in the art will appreciate that the units of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of the two. In order to clearly illustrate the interchangeability of hardware and software, the composition and steps of each example have been generally described in terms of function in the above description. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of this application.

[0305] In the several embodiments provided in the present application, it should be understood that the disclosed systems and devices can be implemented in other ways. For example, the device embodiments described above are only schematic. For example, the division of the units is only a logical function division. There may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. In addition, the mutual coupling or direct coupling or communication connection shown or discussed can be an indirect coupling or communication connection through some interfaces, devices or units, or it can be an electrical, mechanical or other form of connection.

[0306] The units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the embodiments of the present application.

[0307] In addition, each functional unit in each embodiment of the present application may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit. The above-mentioned integrated unit may be implemented in the form of hardware or in the form of software functional units.

[0308] If the integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present application is essentially or the part that contributes to the prior art, or all or part of the technical solution can be embodied in the form of a software product, and the computer software product is stored in a storage medium, including a number of instructions to enable a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the method described in each embodiment of the present application. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), disk or optical disk and other media that can store program codes.

[0309] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any technician familiar with the technical field can easily think of various equivalent modifications or replacements within the technical scope disclosed in the present application, and these modifications or replacements should be included in the protection scope of the present application. Therefore, the protection scope of the present application shall be based on the protection scope of the claims.

Claims

1. A fingerprint recognition device, characterized in that: Applicable to an electronic device including a display screen, the display screen does not include a polarizing plate, and the fingerprint recognition device includes: A linear polarizer array, comprising a plurality of groups of linear polarizers, each group of the plurality of groups of linear polarizers comprising at least two adjacent linear polarizers, and polarization directions of the linear polarizers in each group of the linear polarizers are different from each other; A pixel unit array is arranged below the linear polarizer array, the pixel unit array includes a plurality of groups of pixel units, each group of pixel units in the plurality of groups of pixel units includes at least two pixel units and corresponds to a group of linear polarizers in the linear polarizer array, each pixel unit in each group of pixel units is used to receive a light signal, the light signal includes a first light signal returned by a linear polarized light signal emitted by a light source through a finger surface above the display screen, a second light signal returned by a linear polarized light signal emitted by the light source through an interior of the finger above the display screen, and an ambient light signal, and pixel values ​​of at least two pixel units in each group of pixel units are used to obtain a fingerprint image; Each group of linear polarizers includes three linear polarizers; the multiple groups of pixel units include a first pixel unit group, the first pixel unit group includes a pixel unit X, a pixel unit Y and a pixel unit Z, wherein the absolute value of the difference between the output signals of at least two pixel units among the pixel unit X, the pixel unit Y and the pixel unit Z is used to determine the output signal of the first pixel unit group for the first light signal , the output signal of the first optical signal Used to obtain the fingerprint image; The output signal of the first optical signal satisfy: ;or, The output signal of the first optical signal satisfy: ； in, is the difference between the output signal of the pixel unit X and the output signal of the pixel unit Y, is the difference between the output signal of the pixel unit Y and the output signal of the pixel unit Z, is the difference between the output signal of the pixel unit Z and the output signal of the pixel unit X.

2. The fingerprint recognition device according to claim 1, characterized in that: Each set of linear polarizers includes three linear polarizers with a step of 60°.

3. The fingerprint recognition device according to claim 1 or 2, characterized in that: The second light signal and the ambient light signal are natural light signals, the output signal of the pixel unit X, the output signal of the pixel unit Y, the output signal of the pixel unit Z and the output signal of the first light signal Used to determine the output signal of the first pixel unit group to the natural light signal .

4. The fingerprint recognition device according to claim 3, characterized in that: The output signal of the first optical signal When the output signal of the natural light signal is equal to the absolute value of the difference between the output signals of any two pixel units, the output signal of the natural light signal satisfy: ； in, is the output signal of the pixel unit X, is the output signal of the pixel unit Y, is the output signal of the pixel unit Z.

5. The fingerprint recognition device according to claim 3, characterized in that: The output signal of the first optical signal satisfy: In the case of natural light signal, the output signal satisfy: ； in, is the output signal of the pixel unit X, is the output signal of the pixel unit Y, is the output signal of the pixel unit Z.

6. The fingerprint recognition device according to claim 3, characterized in that: The output signal of the first optical signal satisfy: In the case of natural light signal, the output signal satisfy: ； in, is the output signal of the pixel unit X, is the output signal of the pixel unit Y, is the output signal of the pixel unit Z.

7. The fingerprint recognition device according to claim 1 or 2, characterized in that: The fingerprint recognition device is used to be arranged below the display screen or inside the display screen.

8. The fingerprint recognition device according to claim 7, characterized in that: The display screen includes a display pixel layer. When the fingerprint recognition device is used to be arranged in the display screen, the fingerprint recognition device and the display pixel layer are arranged in the same layer.

9. The fingerprint recognition device according to claim 1 or 2, characterized in that: The light source is at least a portion of display pixels of the display screen.

10. The fingerprint recognition device according to claim 9, characterized in that: The display screen is a micro light emitting diode Micro-LED display screen, or the display screen is a mini light emitting diode Mini-LED display screen.

11. The fingerprint recognition device according to claim 1 or 2, characterized in that: The light source is an external light source, and the external light source is arranged below the display screen.

12. A fingerprint recognition device, characterized in that: Applicable to an electronic device including a display screen, the display screen does not include a polarizing plate, and the fingerprint recognition device includes: A linear polarizer array, comprising a plurality of groups of linear polarizers, each group of the plurality of groups of linear polarizers comprising at least two adjacent linear polarizers, and polarization directions of the linear polarizers in each group of the linear polarizers are different from each other; A pixel unit array is arranged below the linear polarizer array, the pixel unit array includes a plurality of groups of pixel units, each group of pixel units in the plurality of groups of pixel units includes at least two pixel units and corresponds to a group of linear polarizers in the linear polarizer array, each pixel unit in each group of pixel units is used to receive a light signal, the light signal includes a first light signal returned by a linear polarized light signal emitted by a light source through a finger surface above the display screen, a second light signal returned by a linear polarized light signal emitted by the light source through an interior of the finger above the display screen, and an ambient light signal, and pixel values ​​of at least two pixel units in each group of pixel units are used to obtain a fingerprint image; Each group of linear polarizers includes four linear polarizers, the multiple groups of pixel units include a first pixel unit group, the first pixel unit group includes pixel unit A, pixel unit B, pixel unit C and pixel unit D, wherein the absolute value of the difference between the output signals of at least two pixel units among the pixel unit A, pixel unit B, pixel unit C and pixel unit D is used to determine the output signal of the first pixel unit group for the first light signal , the output signal of the first optical signal Used to obtain the fingerprint image; The output signal of the first optical signal satisfy: ;or, The output signal of the first optical signal satisfy: ； in, is the difference between the output signal of the pixel unit A and the output signal of the pixel unit C, is the difference between the output signal of the pixel unit B and the output signal of the pixel unit D.

13. The fingerprint recognition device according to claim 12, characterized in that: Each set of linear polarizers includes four linear polarizers with a step of 45°.

14. The fingerprint recognition device according to claim 12 or 13, characterized in that: The polarization direction of the polarizer corresponding to the pixel unit A is perpendicular to the polarization direction of the polarizer corresponding to the pixel unit C, and the polarization direction of the polarizer corresponding to the pixel unit B is perpendicular to the polarization direction of the polarizer corresponding to the pixel unit D.

15. The fingerprint recognition device according to claim 12 or 13, characterized in that: The second light signal and the ambient light signal are natural light signals, the output signal of the pixel unit A, the output signal of the pixel unit B, the output signal of the pixel unit C, the output signal of the pixel unit D and the output signal of the first light signal Used to determine the output signal of the first pixel unit group to the natural light signal .

16. The fingerprint recognition device according to claim 15, characterized in that: The output signal of the first optical signal is equal to the absolute value of the difference between the output signal of the pixel unit A and the output signal of the pixel unit C; or The output signal of the first optical signal is equal to the absolute value of the difference between the output signal of the pixel unit B and the output signal of the pixel unit D.

17. The fingerprint recognition device according to claim 15, characterized in that: The output signal of the first optical signal satisfy: In the case of natural light signal, the output signal satisfy: ； in, is the output signal of the pixel unit A, is the output signal of the pixel unit B, is the output signal of the pixel unit C, is the output signal of the pixel unit D.

18. The fingerprint recognition device according to claim 15, characterized in that: The output signal of the first optical signal satisfy: In the case of natural light signal, the output signal satisfy: ； in, is the output signal of the pixel unit A, is the output signal of the pixel unit B, is the output signal of the pixel unit C, is the output signal of the pixel unit D.

19. The fingerprint recognition device according to claim 12 or 13, characterized in that: The fingerprint recognition device is used to be arranged below the display screen or inside the display screen.

20. The fingerprint recognition device according to claim 19, characterized in that: The display screen includes a display pixel layer. When the fingerprint recognition device is used to be arranged in the display screen, the fingerprint recognition device and the display pixel layer are arranged in the same layer.

21. The fingerprint recognition device according to claim 12 or 13, characterized in that: The light source is at least a portion of display pixels of the display screen.

22. The fingerprint recognition device according to claim 21, characterized in that: The display screen is a micro light emitting diode Micro-LED display screen, or the display screen is a mini light emitting diode Mini-LED display screen.

23. The fingerprint recognition device according to claim 12 or 13, characterized in that: The light source is an external light source, and the external light source is arranged below the display screen.

24. A display screen, characterized in that: The display screen does not include a polarizing plate, and the display screen includes: Display pixel layer; The fingerprint recognition device according to any one of claims 1 to 11, or the fingerprint recognition device according to any one of claims 12 to 23; Wherein, the display pixel layer and the fingerprint recognition device are arranged on the same layer.

25. An electronic device, characterized in that: include: A display screen, wherein the display screen does not include a polarizing plate; And the fingerprint recognition device as claimed in any one of claims 1 to 11, or the fingerprint recognition device as claimed in any one of claims 12 to 23.

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