WO2022027257A1 - 指纹识别装置和电子设备 - Google Patents

指纹识别装置和电子设备 Download PDF

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Publication number
WO2022027257A1
WO2022027257A1 PCT/CN2020/106915 CN2020106915W WO2022027257A1 WO 2022027257 A1 WO2022027257 A1 WO 2022027257A1 CN 2020106915 W CN2020106915 W CN 2020106915W WO 2022027257 A1 WO2022027257 A1 WO 2022027257A1
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WIPO (PCT)
Prior art keywords
light
fingerprint
fingerprint identification
pixel
identification device
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PCT/CN2020/106915
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English (en)
French (fr)
Inventor
蒋鹏
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深圳市汇顶科技股份有限公司
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Priority to PCT/CN2020/106915 priority Critical patent/WO2022027257A1/zh
Publication of WO2022027257A1 publication Critical patent/WO2022027257A1/zh

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    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06F—ELECTRIC DIGITAL DATA PROCESSING
    • G06F18/00—Pattern recognition

Definitions

  • the present application relates to the field of optical fingerprint technology, and more particularly, to a fingerprint identification device and an electronic device.
  • the microlens array in the fingerprint identification device is located directly above the pixel array, and one microlens corresponds to one pixel unit, that is, each microlens in the microlens array focuses the received light to the same microlens In the corresponding pixel unit, a plurality of pixel units are arranged in an array.
  • the overall light input amount of the fingerprint identification device is small, the exposure time is long, the overall image quality is poor, and the identification performance for dry fingers is poor.
  • the thickness of the optical path in the fingerprint identification device is thick, which increases the processing difficulty and cost of the optical path, and is also not conducive to the development of thin and light fingerprint identification devices.
  • the embodiments of the present application provide a fingerprint identification device and electronic equipment, which can reduce the cost while improving the performance of the fingerprint identification device.
  • a fingerprint identification device which is suitable for use under a display screen to realize off-screen optical fingerprint identification.
  • the fingerprint identification device includes: a fingerprint identification module, including a plurality of fingerprint identification units, the plurality of fingerprint identification units
  • Each fingerprint identification unit in the fingerprint recognition unit includes: a microlens; at least two diaphragm layers are arranged below the microlens, and light-passing holes are set in each filter layer of the at least two diaphragm layers to form different directions
  • the non-light hole area of at least one first diaphragm layer is used to absorb visible light
  • the non-light hole area of at least one second diaphragm layer is used for absorbing visible light.
  • a plurality of pixel units are arranged under the at least two diaphragm layers, and the responsivity of the plurality of pixel units to the non-pixel sensitive light is less than or equal to the first preset Setting a threshold, the responsivity of the pixel sensitive light is greater than or equal to a second preset threshold, the first preset threshold is less than the second preset threshold, and the plurality of pixel units are respectively located at the bottom of the plurality of light guide channels; wherein , after the fingerprint light signal returned after being reflected or scattered from the finger above the display screen is converged by the microlens, wherein a plurality of target fingerprint light signals in different directions are respectively transmitted to the plurality of pixel units through the plurality of light guide channels, The plurality of target fingerprint light signals are used to detect the fingerprint information of the finger.
  • one microlens corresponds to multiple pixel units, and the multiple pixel units respectively receive fingerprint light signals in multiple directions that are converged by the microlens and pass through multiple light guide channels.
  • the optical signals are respectively received by the plurality of pixel units.
  • the angle of the fingerprint light signal received by the plurality of pixel units is determined by the relative positional relationship between the pixel unit and the microlens.
  • the pixel unit can receive the fingerprint light signal of a large angle, which further improves the dryness.
  • the problem of finger recognition is eliminated, and the thickness of the optical path in the fingerprint recognition unit can be further reduced, thereby reducing the thickness of the fingerprint recognition device and the process cost.
  • the diaphragm layer in this solution has lower cost and higher processing precision than traditional vinyl materials, which can improve product consistency and production yield.
  • the size and position can be precisely controlled, which can improve the control accuracy of the light guide channel, thereby improving the imaging quality.
  • the bottom diaphragm layer in this scheme can also absorb the stray light above the pixel unit, further improving the imaging quality. , thereby improving the overall performance of the fingerprint recognition device.
  • the overall light input of the fingerprint identification device is improved, the identification problem of dry fingers is improved, the thickness of the optical path is reduced, and the performance of the fingerprint identification device is comprehensively improved, while the manufacturing process accuracy and yield of the fingerprint identification device are improved. Due to the process cost, the fingerprint identification device in the embodiment of the present application has wider application scenarios at low cost and is beneficial to the development of light and thin electronic equipment in which it is located.
  • the non-light hole area of the first diaphragm layer is also used to transmit infrared light, and the non-light hole area of the first diaphragm layer is a cut-off filter for infrared light to pass through visible light Floor.
  • the fingerprint identification device further includes: an infrared cut-off filter disposed in the optical path between the display screen and the plurality of pixel units in the fingerprint identification module.
  • the infrared cut-off filter is disposed above the fingerprint identification module.
  • arranging the infrared cut filter above the fingerprint identification module can prevent the reflection of optical signals between the filter and the metal layer of the chip where the multiple pixel units are located to form stray light. It is also possible to prevent ambient interference light from entering the pixel unit. In other words, by adopting the structure of the embodiment of the present application, stray light and ambient interference light can be reduced, the quality of fingerprint images can be improved, and the overall performance of the fingerprint identification device can be further improved.
  • the non-pixel-sensitive light is light of a first color
  • the pixel-sensitive light includes light of a second color
  • the non-light hole area in the second diaphragm layer is used to pass through the first color color light and absorb the second color light.
  • the first color light is blue light
  • the non-light aperture area of the second diaphragm layer is a filter layer formed by a blue filter material or a filter formed by a violet filter material Floor.
  • the display screen is configured to emit the second color light in the finger pressing area, and the second color fingerprint light returned after the second color light is reflected or scattered from the finger is converged by the microlens Then, the plurality of second color target fingerprint light signals in different directions are respectively transmitted to the plurality of pixel units through the plurality of light guide channels, and the plurality of second color target fingerprint light signals are used to detect the fingerprint information of the finger.
  • the second color light is green light or cyan light.
  • the first preset threshold is less than or equal to 10%
  • the second preset threshold is greater than or equal to 70%
  • the absorption rate of the light sensitive to the pixel in the non-light aperture area of the at least one second aperture layer is greater than a third preset threshold.
  • the third preset threshold is greater than or equal to 70%.
  • the at least two diaphragm layers are three diaphragm layers
  • the intermediate diaphragm layer among the three diaphragm layers is the first diaphragm layer
  • the top diaphragm layer and the bottom diaphragm layer are the second diaphragm layer.
  • a plurality of light-transmitting holes corresponding to the plurality of pixel units in a one-to-one correspondence are provided in the middle-layer diaphragm layer of the three-layer diaphragm layers, so as to form the plurality of light guide channels .
  • the top diaphragm layer of the three diaphragm layers is provided with a light-passing hole
  • the bottom diaphragm layer of the three diaphragm layers is provided with pixels corresponding to the plurality of pixels.
  • the units have a one-to-one correspondence with a plurality of light-transmitting holes to form the plurality of light-guiding channels.
  • the plurality of pixel units are formed in a sensor chip, and the optical path height between the lower surface of the microlens and the upper surface of the sensor chip is H,
  • the distance between the bottom diaphragm layer in the three-layer diaphragm layer and the upper surface of the sensor chip is between 0 and H/3
  • the middle layer diaphragm layer in the three-layer diaphragm layer is between the upper surface of the sensor chip and the sensor chip.
  • the distance between them is between H/5 and 2H/3
  • the distance between the top diaphragm layer of the at least two diaphragm layers and the upper surface of the sensor chip is between H/2 and H.
  • the at least two diaphragm layers are two diaphragm layers
  • the bottom diaphragm layer of the two diaphragm layers is the first diaphragm layer
  • the two diaphragm layers are The top diaphragm layer of is the second diaphragm layer.
  • the bottom diaphragm layer of the two diaphragm layers is provided with a plurality of light through holes corresponding to the plurality of pixel units respectively, so as to form the plurality of light guide channels.
  • a light-passing hole is provided in the top diaphragm layer of the two diaphragm layers, so as to form the plurality of light guide channels.
  • the plurality of pixel units are formed in a sensor chip, and the optical path height between the lower surface of the microlens and the upper surface of the sensor chip is H,
  • the distance from the bottom diaphragm layer of the at least two diaphragm layers to the upper surface of the sensor chip is between H/5 and 2H/3, and the top diaphragm layer of the at least two diaphragm layers to the sensor
  • the distance between the top surfaces of the chips is between H/2 and H.
  • the apertures of the light-transmitting holes in the plurality of light-guiding channels decrease sequentially from top to bottom.
  • the plurality of pixel units are formed in a sensor chip, the diameter of the microlens is D, the height of the optical path between the lower surface of the microlens and the upper surface of the sensor chip is H, the at least The optical path height between one of the two diaphragm layers and the upper surface of the sensor chip is h, and the aperture d of the through hole in the one layer of diaphragm layers is (1 ⁇ 0.3) ⁇ D ⁇ h/ between the range of H.
  • the fingerprint identification device further includes: a metal circuit layer, wherein a plurality of light-passing holes are arranged in the metal circuit layer, and the plurality of light-passing holes are disposed in the plurality of pixel units in a one-to-one correspondence. above, and are disposed below the plurality of light guide channels in a one-to-one correspondence;
  • the plurality of target fingerprint optical signals are conducted to the plurality of light-passing holes in the metal circuit layer through the plurality of light-guiding channels, and are conducted to the plurality of pixel units through the plurality of light-passing holes.
  • the center of the light-passing hole in the first light-guiding channel of the plurality of light-guiding channels is located on a first straight line, and the through hole in the metal circuit layer corresponding to the first light-guiding channel The light aperture is also located on the first straight line.
  • the light-passing holes in the at least two diaphragm layers and the light-passing holes in the metal circuit layer are both circular light-passing holes.
  • the diameter of the through hole in the metal circuit layer is smaller than the diameter of the through hole in the bottom diaphragm layer of the at least two diaphragm layers.
  • each fingerprint identification unit further includes: a transparent medium layer for connecting the at least two diaphragm layers.
  • each fingerprint identification unit further includes: a first buffer layer, used to connect the microlens and the top diaphragm layer of the at least two diaphragm layers; a second buffer layer, used and connecting the sensor chip and the bottom diaphragm layer of the at least two diaphragm layers.
  • the difference between the refractive indices of the transparent medium layer and the first buffer layer, and the difference between the refractive indices of the transparent medium layer and the second buffer layer are both within a preset threshold.
  • the plurality of pixel units are four pixel units, the four pixel units form a pixel area of a quadrilateral area, the center point of the pixel area and the center of the microlens in the vertical direction or not coincident.
  • the plurality of light guide channels are four light guide channels, and the directions of at least three light guide channels among the directions of the four light guide channels are inclined with respect to the display screen.
  • the pixel units in the four pixel units can respectively receive the fingerprint light signal in the oblique direction, and the fingerprint light signal in the oblique direction can improve the fingerprint recognition problem of dry fingers, And the thickness of the fingerprint identification device can be reduced.
  • the included angle between the four light guide channels and the direction perpendicular to the display screen is between 10° and 45°.
  • the solution of the embodiments of the present application can improve the problem of dry finger recognition while satisfying the intensity of the optical signal and controlling the thickness of the optical path of the entire fingerprint recognition device.
  • the four pixel units respectively include four photosensitive regions, and the four photosensitive regions are respectively located at the bottom of the four light guide channels.
  • At least one of the four photosensitive regions is deviated from the center of the pixel unit where it is located.
  • the at least one photosensitive area is deviated in a direction away from the center of the microlens.
  • the four pixel units form a quadrilateral pixel area, and the four photosensitive areas are respectively located at four corners of the pixel area.
  • the fingerprint identification module includes multiple groups of the four pixel units; the optical signals received by the multiple first pixel units in the multiple groups of the four pixel units are used to form the The first fingerprint image of the finger, the optical signals received by the plurality of second pixel units in the plurality of groups of the four pixel units are used to form the second fingerprint image of the finger, and the plurality of third The light signal received by the pixel unit is used to form the third fingerprint image of the finger, the light signal received by the plurality of fourth pixel units in the multiple groups of the four pixel units is used to form the fourth fingerprint image of the finger, the first fingerprint image One or more of the fingerprint image, the second fingerprint image, the third fingerprint image, and the fourth fingerprint image are used for fingerprint identification.
  • every X1 ⁇ X2 first pixel units in the plurality of first pixel units are connected to a first summing and averaging circuit to perform physical pixel synthesis to form a pixel value in the first intermediate fingerprint image ;
  • Every X1 ⁇ X2 second pixel units in the plurality of second pixel units are connected to the second summing and averaging circuit to perform physical pixel synthesis to form a pixel value in the second intermediate fingerprint image;
  • the plurality of third pixel units Every X1 ⁇ X2 third pixel unit is connected to the third summing and averaging circuit to perform physical pixel synthesis to form a pixel value in the third intermediate fingerprint image;
  • every X1 ⁇ X2 fourth pixel unit in the plurality of fourth pixel units The pixel unit is connected to the fourth summing and averaging circuit to perform physical pixel synthesis to form a pixel value in the fourth intermediate fingerprint image; wherein X1 and X2 are positive integers.
  • the fingerprint identification device further includes: the first summing and averaging circuit, the second summing and averaging circuit, the third summing and averaging circuit, and the fourth summing and averaging circuit.
  • every Y1 ⁇ Y2 pixel value in the first intermediate fingerprint image is used for digital pixel synthesis to form a pixel value in the first fingerprint image; every pixel value in the second intermediate fingerprint image is used for digital pixel synthesis.
  • Y1 ⁇ Y2 pixel values are used for digital pixel synthesis to form one pixel value in the second fingerprint image; every Y1 ⁇ Y2 pixel value in the third intermediate fingerprint image is used for digital pixel synthesis to form the third A pixel value in the fingerprint image; every Y1 ⁇ Y2 pixel value in the fourth intermediate fingerprint image is used for digital pixel synthesis to form a pixel value in the fourth fingerprint image; wherein Y1 and Y2 are positive integers.
  • the fingerprint identification device further includes: a processing unit, configured to perform processing on the first intermediate fingerprint image, the second intermediate fingerprint image, the third intermediate fingerprint image and the fourth intermediate fingerprint image Digital pixel synthesis.
  • the number of pixels in the process of fingerprint image processing can be reduced, and the speed of fingerprint recognition can be improved.
  • the pixel value can still be obtained through the pixel synthesis output, which will not affect the formation of the fingerprint image and the effect of fingerprint recognition.
  • the first intermediate fingerprint image, the second intermediate fingerprint image, the third intermediate fingerprint image and the fourth intermediate fingerprint image are used for digital pixel synthesis after low-pass filtering processing.
  • the fingerprint identification device further includes: a low-pass filter for the first intermediate fingerprint image, the second intermediate fingerprint image, the third intermediate fingerprint image and the fourth intermediate fingerprint The image is low-pass filtered.
  • the plurality of first pixel units are not adjacent to each other, the plurality of second pixel units are not adjacent to each other, and the plurality of third pixel units are not adjacent to each other , and the plurality of fourth pixel units are not adjacent to each other.
  • the arrangement period of the light-emitting pixels in the display screen is P1
  • the spatial sampling period of the fingerprint identification device is P2 ⁇ P1/2.
  • the spatial sampling period of the fingerprint identification device can satisfy the Nyquist sampling law relative to the spatial imaging period of the display screen, that is, Moire fringes can be avoided in the fingerprint image, and accordingly, the fingerprint identification effect can be improved .
  • the spatial sampling period of the fingerprint identification device is calculated according to the arrangement period of the plurality of fingerprint identification units and the pixel synthesis method.
  • the arrangement period of the plurality of fingerprint identification units is between 12 ⁇ m and 20 ⁇ m.
  • the optical path thickness of each fingerprint identification unit in the plurality of fingerprint identification units is within 30 ⁇ m.
  • the distance between the fingerprint identification device and the display screen is 0 to 1 mm.
  • an electronic device including: a display screen; and the fingerprint identification device in the first aspect or any possible implementation manner of the first aspect, the fingerprint identification device is disposed below the display screen, so as to realize Under-screen optical fingerprint recognition.
  • the display screen is used to display green, cyan or white light spots in the fingerprint detection area
  • the fingerprint identification device is used to receive green, cyan or white target fingerprint light signals to detect the fingerprint information of the finger.
  • the distance between the fingerprint identification device and the display screen is 0 to 1 mm.
  • Providing the above fingerprint identification device in an electronic device improves the fingerprint identification performance of the fingerprint identification device and reduces the cost of the fingerprint identification device, thereby improving the fingerprint identification performance of the electronic device and reducing the cost of the electronic device.
  • FIG. 1 is a schematic structural diagram of an electronic device to which an embodiment of the present application is applied.
  • FIG. 2 is a schematic cross-sectional view of a fingerprint identification device provided by an embodiment of the present application.
  • FIG. 3 is a schematic cross-sectional view of another fingerprint identification device provided by an embodiment of the present application.
  • FIG. 4 is a schematic top view of the fingerprint identification device in FIG. 3 .
  • FIG. 5 is a schematic structural diagram of an electronic device according to an embodiment of the present application.
  • FIG. 6 is a schematic diagram of related structural parameters of three diaphragm layers in a fingerprint identification unit according to an embodiment of the present application.
  • FIG. 7 is a schematic top view of a fingerprint identification unit in FIG. 3 .
  • FIG. 8 is another schematic top view of a fingerprint identification unit in FIG. 3 .
  • FIG. 9 is a schematic cross-sectional view of another fingerprint identification device provided by an embodiment of the present application.
  • FIG. 10 is a schematic diagram of a pixel array in a fingerprint identification device according to an embodiment of the present application.
  • FIG. 11 is a schematic diagram of an image processing method according to an embodiment of the present application.
  • embodiments of the present application can be applied to optical fingerprint systems, including but not limited to optical fingerprint recognition systems and products based on optical fingerprint imaging.
  • the embodiments of the present application only take the optical fingerprint system as an example for description, but should not be implemented in this application.
  • the examples constitute any limitation, and the embodiments of the present application are also applicable to other systems using optical imaging technology, and the like.
  • the optical fingerprint system provided in the embodiments of the present application can be applied to smart phones, tablet computers, and other mobile terminals with display screens or other electronic devices; more specifically, in the above electronic devices, fingerprint identification
  • the device may specifically be an optical fingerprint device, which may be arranged in a partial area or all areas below the display screen, thereby forming an under-display optical fingerprint system.
  • the fingerprint identification device may also be partially or fully integrated into the display screen of the electronic device, thereby forming an in-display optical fingerprint system.
  • FIG. 1 is a schematic structural diagram of an electronic device to which this embodiment of the present application can be applied.
  • the electronic device 10 includes a display screen 120 and an optical fingerprint device 130 , wherein the optical fingerprint device 130 is disposed in a local area below the display screen 120 .
  • the optical fingerprint device 130 includes an optical fingerprint sensor, and the optical fingerprint sensor includes a sensing array 133 having a plurality of optical sensing units 131 .
  • the fingerprint detection area 103 is located in the display area of the display screen 120 .
  • the optical fingerprint device 130 can also be arranged at other positions, such as the side of the display screen 120 or the non-light-transmitting area of the edge of the electronic device 10, and at least part of the display area of the display screen 120 is designed by the optical path.
  • the optical signal is guided to the optical fingerprint device 130 , so that the fingerprint detection area 103 is actually located in the display area of the display screen 120 .
  • the area of the fingerprint detection area 103 may be different from the area of the sensing array of the optical fingerprint device 130.
  • the optical fingerprint can be made The area of the fingerprint detection area 103 of the device 130 is larger than the area of the sensing array of the optical fingerprint device 130 .
  • the fingerprint detection area 103 of the optical fingerprint device 130 can also be designed to be substantially the same as the area of the sensing array of the optical fingerprint device 130 .
  • the electronic device 10 using the above structure does not need to reserve a space on the front of the electronic device 10 to set the fingerprint button (such as the Home button), so that a full-screen solution can be adopted, that is, the display area of the display screen 120 can be basically Extends to the entire front of the electronic device 10 .
  • the optical fingerprint device 130 includes a light detection part 134 and an optical component 132
  • the light detection part 134 includes a sensing array and a reading circuit electrically connected to the sensing array and Other auxiliary circuits, which can be fabricated on a chip (Die) by a semiconductor process, such as an optical imaging chip or an optical fingerprint sensor
  • the sensing array is specifically a photo detector (Photo detector) array, which includes a plurality of A light detector, the light detector can be used as the above-mentioned optical sensing unit
  • the optical component 132 can be arranged above the sensing array of the light detection part 134, which can specifically include a light guide layer or an optical path guide structure and other optical elements, the The light guide layer or the light path guide structure is mainly used to guide the reflected light from the finger surface to the sensing array for optical detection.
  • the optical assembly 132 and the light detection part 134 can be packaged in the same optical fingerprint component.
  • the optical component 132 and the optical detection part 134 can be packaged in the same optical fingerprint chip, or the optical component 132 can be arranged outside the chip where the optical detection part 134 is located, for example, the optical component 132 can be attached to the Above the chip, or some elements of the optical assembly 132 are integrated in the above-mentioned chip.
  • the light guide layer may be a collimator layer fabricated on a semiconductor silicon wafer, which has a plurality of collimator layers.
  • the collimation unit can be specifically a small hole, from the reflected light from the finger, the light perpendicularly incident to the collimation unit can pass through and be received by the optical sensing unit below it, and the incident angle Excessive light is attenuated by multiple reflections inside the collimating unit, so each optical sensing unit can basically only receive the reflected light from the fingerprint lines directly above it, so that the sensing array can detect the finger. Fingerprint image.
  • the light guide layer or the light path guide structure may also be an optical lens (Lens) layer, which has one or more lens units, such as a lens group composed of one or more aspherical lenses, which are used for The reflected light reflected from the finger is collected to the sensing array of the light detection part 134 below it, so that the sensing array can perform imaging based on the reflected light, thereby obtaining a fingerprint image of the finger.
  • the optical lens layer may further be formed with pinholes in the optical path of the lens unit, and the pinholes may cooperate with the optical lens layer to expand the field of view of the optical fingerprint device to improve the fingerprint imaging effect of the optical fingerprint device 130 .
  • the light guide layer or the light path guide structure may also specifically use a micro-lens (Micro-Lens) layer, and the micro-lens layer has a micro-lens array formed by a plurality of micro-lenses, which can be produced by a semiconductor growth process or other The process is formed over the sensing array of the light detection part 134, and each microlens may respectively correspond to one of the sensing units of the sensing array.
  • other optical film layers such as a dielectric layer or a passivation layer, may also be formed between the microlens layer and the sensing unit.
  • the micro-hole is formed between its corresponding micro-lens and the sensing unit, and the light blocking layer can block the optical interference between adjacent micro-lenses and the sensing unit, and make the light corresponding to the sensing unit converge to the inside of the micro-hole through the micro-lens and transmitted to the sensing unit through the micro-hole for optical fingerprint imaging.
  • a microlens layer may be further provided under the collimator layer or the optical lens layer.
  • the collimator layer or the optical lens layer is used in combination with the microlens layer, its specific laminated structure or optical path may need to be adjusted according to actual needs.
  • the display screen 120 may be a display screen having a self-luminous display unit, such as an organic light-emitting diode (Organic Light-Emitting Diode, OLED) display screen or a micro light-emitting diode (Micro-LED) display screen.
  • OLED Organic Light-Emitting Diode
  • Micro-LED micro light-emitting diode
  • the optical fingerprint device 130 can use the display unit (ie, the OLED light source) of the OLED display screen 120 located in the fingerprint detection area 103 as the excitation light source for optical fingerprint detection.
  • the display screen 120 emits a beam of light 111 to the target finger 140 above the fingerprint detection area 103 .
  • the scattered light is formed, and in the related patent application, for the convenience of description, the above-mentioned reflected light and scattered light are collectively referred to as reflected light. Since the ridges and valleys of the fingerprint have different reflection capabilities for light, the reflected light 151 from the fingerprint ridge 141 and the reflected light 152 from the fingerprint valley 142 have different light intensities, and the reflected light passes through the optical component 132 After that, it is received by the sensing array 134 in the optical fingerprint device 130 and converted into a corresponding electrical signal, that is, a fingerprint detection signal; based on the fingerprint detection signal, fingerprint image data can be obtained, and fingerprint matching verification can be further performed, so that the electronic The device 10 implements an optical fingerprint recognition function.
  • the optical fingerprint device 130 may also use a built-in light source or an external light source to provide an optical signal for fingerprint detection.
  • the optical fingerprint device 130 may be suitable for a non-self-luminous display screen, such as a liquid crystal display screen or other passive light-emitting display screens.
  • the optical fingerprint system of the electronic device 10 may further include an excitation light source for optical fingerprint detection.
  • the optical fingerprint device 130 can be specifically an infrared light source or a light source of non-visible light with a specific wavelength, which can be arranged under the backlight module of the liquid crystal display or the edge area under the protective cover of the electronic device 10, and the optical fingerprint device 130 can be arranged with a liquid crystal panel or Under the edge area of the protective cover plate and guided by the optical path, the fingerprint detection light can reach the optical fingerprint device 130; alternatively, the optical fingerprint device 130 can also be arranged below the backlight module, and the backlight module
  • the film layers such as the reflective sheet are perforated or otherwise optically designed to allow the fingerprint detection light to pass through the liquid crystal panel and the backlight module and reach the optical fingerprint device 130 .
  • the optical fingerprint device 130 uses a built-in light source or an external light source to provide an optical signal for fingerprint detection, the detection principle thereof is consistent with the content described above.
  • the electronic device 10 further includes a transparent protective cover plate, which may be a glass cover plate or a sapphire cover plate, which is located above the display screen 120 and covers the front surface of the electronic device 10 .
  • a transparent protective cover plate which may be a glass cover plate or a sapphire cover plate, which is located above the display screen 120 and covers the front surface of the electronic device 10 .
  • the so-called finger pressing on the display screen 120 actually refers to pressing the cover plate above the display screen 120 or the surface of the protective layer covering the cover plate.
  • the electronic device 10 may further include a circuit board 150 disposed below the optical fingerprint device 130 .
  • the optical fingerprint device 130 can be adhered to the circuit board 150 by adhesive, and is electrically connected to the circuit board 150 by bonding pads and metal wires.
  • the optical fingerprint device 130 can realize electrical interconnection and signal transmission with other peripheral circuits or other elements of the electronic device 10 through the circuit board 150 .
  • the optical fingerprint device 130 can receive the control signal of the processing unit of the electronic device 10 through the circuit board 150 , and can also output the fingerprint detection signal from the optical fingerprint device 130 to the processing unit or the control unit of the electronic device 10 through the circuit board 150 . Wait.
  • the optical fingerprint device 130 may only include one optical fingerprint sensor.
  • the fingerprint detection area 103 of the optical fingerprint device 130 has a small area and a fixed position, so the user needs to input a fingerprint. Press the finger to a specific position of the fingerprint detection area 103 , otherwise the optical fingerprint device 130 may fail to capture the fingerprint image, resulting in poor user experience.
  • the optical fingerprint device 130 may specifically include multiple optical fingerprint sensors; the multiple optical fingerprint sensors may be arranged side by side under the display screen 120 by splicing, and the sensing areas of the multiple optical fingerprint sensors share a common The fingerprint detection area 103 of the optical fingerprint device 130 is constituted.
  • the fingerprint detection area 103 of the optical fingerprint device 130 may include a plurality of sub-areas, and each sub-area corresponds to the sensing area of one of the optical fingerprint sensors, so that the fingerprint collection area 103 of the optical fingerprint device 130 may be extended to display
  • the main area of the lower part of the screen is extended to the area where the finger is usually pressed, so as to realize the blind-pressing fingerprint input operation.
  • the fingerprint detection area 103 can also be extended to half the display area or even the entire display area, so as to realize fingerprint detection on a half screen or a full screen.
  • the sensing array in the optical fingerprint device may also be called a pixel array, and the optical sensing unit or sensing unit in the sensing array may also be called a pixel unit or a pixel.
  • optical fingerprint device in the embodiments of the present application may also be referred to as an optical fingerprint identification module, a fingerprint identification device, a fingerprint identification module, a fingerprint module, a fingerprint collection device, etc., and the above terms can be interchanged.
  • FIG. 2 shows a schematic cross-sectional view of a fingerprint identification device.
  • the fingerprint identification device 200 includes a microlens array 210 , at least one light blocking layer 220 , a pixel array 230 and a filter 240 .
  • the microlens array 210 is located directly above the pixel array 230 and at least one light blocking layer 220, and one microlens 211 corresponds to one pixel unit 231, that is, the light that each microlens 211 in the microlens array 210 will receive The light is focused into the pixel unit 231 corresponding to the same microlens 211 through at least one small hole 2201 of the light blocking layer 220 .
  • the optical signal received by each microlens 211 is mainly a fingerprint optical signal incident perpendicular to the microlens array 210 after being reflected or scattered by the finger above the display screen.
  • the pixel array 230 is formed in the substrate 201, and each pixel unit 231 in the pixel array 230 includes a photosensitive area (active area, AA) 2311, and the photosensitive area 2311 can be the photosensitive area of the photodiode, It is used to convert the received fingerprint optical signal into the corresponding electrical signal value.
  • a metal wiring layer 233 is formed above the pixel array 230 for transmitting electrical signals of each pixel unit 231 in the pixel array 230 .
  • the metal circuit layer 233 is also formed with small holes, which can be used to transmit fingerprint light signals to the pixel unit 231 .
  • a protective layer 234 may be formed, and the protective layer 234 may include: silicon oxide, silicon nitride and/or silicon oxynitride.
  • the substrate 201, the pixel array 230, the metal circuit layer 233 and the protective layer 234 on the surface in FIG. 2 may be a schematic stack structure in an image sensor chip.
  • the image sensor type and its specific chip structure are not limited.
  • a filter 240 can be grown directly, and the filter 240 can be an infrared cut (IR-cut, IRC) filter, which is used to detect infrared light, near-infrared light and Part of the infrared signal is cut off.
  • IR-cut infrared cut
  • IRC infrared cut
  • a transparent medium layer and at least one light blocking layer 220 are regrown.
  • the at least one light-blocking layer 220 is made of black glue for absorbing and blocking light signals.
  • the plurality of microlenses 211 in the microlens array 210 and the plurality of pixel units 231 in the pixel array 230 are in one-to-one correspondence, and the photosensitive regions 2311 of the plurality of pixel units 231 in the pixel array 230 are in one-to-one correspondence. Periodically arranged and evenly distributed.
  • the photosensitive area of the pixel array 230 is affected by the size of the microlens array 210, and the thickness of the fingerprint identification device 200 is relatively large, thereby increasing the processing difficulty, cycle and cost of the optical path of the fingerprint identification device 200.
  • the fingers are usually dry, and their cuticles are not uniform. When they are pressed on the display screen, there will be poor contact in the local area of the fingers. . When the dry finger is not in good contact with the display screen, the contrast between the fingerprint ridges and the fingerprint valleys of the fingerprint image in the vertical direction formed by the fingerprint identification device 200 is poor, and the image is so blurred that the fingerprint texture cannot be distinguished. Fingerprint recognition performance is poor.
  • the surface of the optical filter 240 generally has a high reflectivity
  • the metal circuit layer 234 on the sensor chip also has a high reflectivity for optical signals. Signals are easily reflected between the optical filter 240 and the metal circuit layer 234 to form an optical waveguide effect and generate more stray light. The stray light easily enters the pixel unit and affects the image quality of the fingerprint identification device.
  • At least one light-blocking layer 220 made of black glue material has high cost and low processing accuracy, that is, the size and position of the small holes in the light-blocking layer 220 are limited. accuracy, thereby limiting the overall performance of the fingerprint recognition device.
  • the present application proposes an improved fingerprint identification device, which can solve the problems of high cost and poor performance of the above-mentioned fingerprint identification device.
  • FIG. 3 is a schematic cross-sectional view of a fingerprint identification device 300 provided by an embodiment of the present application
  • FIG. 4 is a schematic top view of a fingerprint identification device 300 provided by an embodiment of the present application.
  • FIG. 3 may be a schematic cross-sectional view along the direction A-A' in FIG. 4 .
  • the fingerprint identification device 300 includes:
  • the fingerprint identification module includes a plurality of fingerprint identification units 302, and each fingerprint identification unit in the plurality of fingerprint identification units 302 includes:
  • Micro lens 310
  • At least two diaphragm layers such as the top diaphragm layer 320, the middle diaphragm layer 340 and the bottom diaphragm layer 350 in FIG.
  • Each of the diaphragm layers is provided with through holes to form a plurality of light guide channels in different directions; among the at least two diaphragm layers, at least one of the first diaphragm layers has non-light holes The area is used for absorbing visible light, and the non-light aperture area of at least one second diaphragm layer is used for transmitting non-pixel sensitive light;
  • a plurality of pixel units for example, two pixel units 331 and 334 are shown in FIG. 3 , the plurality of pixel units are arranged under the above-mentioned at least two diaphragm layers, and the plurality of pixel units are located in one-to-one correspondence respectively.
  • the bottom of the plurality of light guide channels, and the responsivity of the plurality of pixel units to non-pixel sensitive light is less than the first preset threshold;
  • the multiple target fingerprint light signals in different directions are respectively transmitted to the multiple pixel units through the multiple light guide channels, and The multiple target fingerprint light signals are used to detect the fingerprint information of the finger.
  • the optical path structure of each fingerprint identification unit in the multiple fingerprint identification units is independent of each other, for example, as In the two fingerprint identification units shown in FIG. 3 , the microlens in one fingerprint identification unit transmits the optical signal received by it to the corresponding pixel unit below it.
  • the structures of the plurality of fingerprint identification units may also be interleaved.
  • a microlens in one fingerprint identification unit can condense the oblique light signal it receives to a pixel unit below the microlens in an adjacent fingerprint identification unit.
  • one microlens converges the received oblique light signal to the pixel unit below the microlens adjacent to the microlens.
  • the plurality of fingerprint identification units may be arranged in a square array, and the plurality of microlenses in the plurality of fingerprint identification units form a square array of microlenses In the array, the centers of four adjacent microlenses form a square.
  • the plurality of fingerprint identification units may also be arranged in a diamond-shaped array, and the plurality of microlenses in the plurality of fingerprint identification units form a diamond-shaped microlens array, and the centers of four adjacent microlenses form a rhombus.
  • the plurality of fingerprint identification units in the embodiments of the present application can also be arranged in other arbitrary forms in the vertical space and the horizontal space, and the embodiments of the present application do not. Specific restrictions.
  • the microlens 310 may be various lenses with a converging function to increase the field of view and increase the amount of light signals transmitted to the pixel unit.
  • the material of the microlens 310 can be an organic material, such as resin.
  • the surface of the microlens 310 may be spherical or aspherical.
  • the microlens 310 may be a circular lens or a square lens, etc., which is not limited in this embodiment of the present application.
  • the microlens 310 is a circular microlens, its manufacturing cost is lower than that of a square microlens, which can reduce the overall manufacturing cost of the fingerprint identification device.
  • the diameter of the circular microlenses is not greater than the arrangement period of the above-mentioned plurality of pixel units.
  • the diameter of the microlens 310 is smaller than or equal to A.
  • the plurality of microlenses in the plurality of fingerprint identification units form a square array of microlenses.
  • the diameter of the circular microlens is (L-1) ⁇ m, and the orthographic projection of the center of the circular microlens on the square area is located at the center of the square area.
  • the pixel unit may be a photoelectric conversion unit.
  • the pixel unit may include a photodiode (PD), a switch tube, etc., wherein the switch tube is used to receive a control signal to control the operation of the photodiode, and may be used to control the output of an electrical signal of the photodiode.
  • the plurality of pixel units in the fingerprint identification unit 302 may be quadrilateral pixel units, such as square pixel units.
  • the pixel unit may be formed in the substrate by a semiconductor process, and the pixel units in the plurality of fingerprint identification units may form a pixel array, and the pixel array is formed by one or more metal circuit layers (for example, FIG. The metal circuit layer 335) shown in 3) is electrically connected, and the one or more metal circuit layers, the pixel array, the substrate, etc.
  • an image sensor chip 330 can be a CMOS image sensor or also It can be a CCD sensor, and it can be understood that in addition to the above-mentioned metal circuit layer, pixel array and substrate, the image sensor can also include necessary dielectric layers or other laminated structures, for example, one or more metal layers The dielectric layer in between, and the protective layer above the topmost metal layer, etc., for the content of this part, reference may be made to the relevant description of the prior art, which will not be described in detail in this application.
  • the at least two diaphragm layers may be filter material layers that transmit optical signals in target wavelength bands and cut off optical signals in non-target wavelength bands, wherein light-passing holes are provided to confine light beams to realize imaging.
  • the at least two diaphragm layers include at least one first diaphragm layer, and the non-light aperture area of the first diaphragm layer is used to absorb visible light.
  • the first diaphragm layer may transmit infrared light. (IR-pass, IRP) visible light cut-off filter layer, the infrared light through the visible light cut-off filter layer and the infrared light cut-off filter layer above the fingerprint identification unit are combined with each other, which can cut off all visible light and infrared light signals, Therefore, the combination of the visible light cut-off filter layer and the infrared light cut-off filter layer can play a good light blocking effect.
  • IRP infrared light
  • the cost of at least one layer of the first diaphragm layer in the present application is lower, and the processing precision is high, which can improve the consistency of products and the production quality.
  • the size and position of the light-passing holes in the at least one first diaphragm layer can be precisely controlled, thereby improving the control accuracy of the light-guiding channel and improving the overall performance of the fingerprint identification device.
  • the at least two diaphragm layers further include at least one second diaphragm layer, and the at least one second diaphragm layer is used to transmit non-pixel-sensitive light, and the non-pixel-sensitive light is insensitive to the pixel unit.
  • the light signal that is, the responsivity of the pixel unit to the non-pixel sensitive light is small or has no response, for example, less than the first preset threshold. In other words, even if the pixel unit receives the non-pixel sensitive light, the pixel unit does not convert the non-pixel sensitive light into an electrical signal or the converted electrical signal is small.
  • the non-pixel sensitive light may be a first color light
  • the first color light includes, but is not limited to, blue light, or may also be light signals of other colors.
  • the first preset threshold may be less than or equal to 10%, the responsivity of the pixel unit to the first color light is less than 10%, and as an example, the quantum efficiency of the pixel unit to blue light is less than 10%.
  • the non-light hole area of the at least one second diaphragm layer is also used to absorb the pixel sensitive light while transmitting the non-pixel sensitive light, and the non-penetrating light of the at least one second diaphragm layer
  • the absorptivity of the light sensitive to the pixel in the hole region is larger, for example, larger than a third preset threshold.
  • the pixel sensitive light is a light signal to which the pixel unit is sensitive, that is, the pixel unit has a relatively large responsivity to the pixel sensitive light, for example, greater than the second preset threshold, and the second preset threshold is greater than the above-mentioned first preset threshold.
  • the pixel unit when the pixel unit receives the pixel sensitive light, the pixel unit corresponds to the pixel sensitive light and converts it into a corresponding electrical signal.
  • the pixel-sensitive light may include a second color light, and the second color light includes, but is not limited to, green light or cyan light, or may also be other light signals different from the first color light.
  • the above-mentioned second preset threshold and third preset threshold may be greater than or equal to 70%, specifically, the responsivity of the pixel unit to the second color light is greater than 70%, and the non-passage of the second diaphragm layer
  • the absorption rate of the second color light in the aperture area is greater than 70%.
  • the quantum efficiency of the pixel unit for green light is greater than 70%, and the absorption rate of the green light in the non-light aperture area of the second aperture layer is greater than 70%.
  • the second diaphragm layer may be a diaphragm layer composed of a second color filter material, for example, it may be a blue filter layer or a violet filter layer
  • the at least one second diaphragm layer in the present application also has lower cost and high processing precision, which is beneficial to further improve the consistency of products and the production quality.
  • the cost of the fingerprint identification device can be further reduced and the performance of the fingerprint identification device can be improved under the condition that good light blocking can be ensured.
  • the numerical values of the first preset threshold value, the second preset threshold value, and the third preset threshold value are all exemplary descriptions, and the specific numerical values thereof are not limited in this embodiment of the present application.
  • the combination of the corresponding diaphragm layers is designed, which can reduce the influence of stray light on the pixel units and further improve the imaging quality on the basis of reducing the cost.
  • the pixel unit in the fingerprint identification unit 302 has the highest response to green light or cyan light, and the fingerprint image generated by the pixel array formed by the plurality of fingerprint identification units 302 has better quality and higher contrast.
  • the responsivity to green light or cyan light is the highest, and when fingerprint identification is performed, the light source can emit green or cyan light signals, which can further reduce stray light signals in other wavelength bands. .
  • the light source may also send out other light signals including green light signals, such as white light signals, etc., which is not limited in this embodiment of the present application.
  • FIG. 5 is a schematic structural diagram of an electronic device according to an embodiment of the present application.
  • the fingerprint identification device if the fingerprint identification device is arranged below the display screen 120, and the light source used by the fingerprint identification device is the display screen 120 when performing fingerprint identification, then the fingerprint identification device corresponds to the finger when performing fingerprint identification.
  • the light-emitting area 121 of the display screen displays green, cyan or white light spots to provide a light source for fingerprint identification.
  • the multiple green target fingerprint light signals in different directions are respectively transmitted through multiple light guide channels.
  • the plurality of green target fingerprint light signals are used to detect the fingerprint information of the finger.
  • the fingerprint identification device 300 may include an infrared cut-off filter 301, and the infrared cut-off filter 301 is arranged between the display screen 120 and a plurality of pixel units in the fingerprint identification module. in the light path.
  • the infrared cut-off filter 301 is used to prevent the infrared light signal in the environment from entering the fingerprint identification module, thereby affecting the fingerprint identification result. Further, the infrared cut filter 301 can also prevent near-infrared light signals and some or all of the red light signals in the visible light from entering the pixel unit. Light and infrared light enter into the pixel unit.
  • the infrared cut-off filter 301 may be disposed on the surface of the image sensor chip where the plurality of pixel units are located, and reference may be made to the relevant description in FIG. 2 for the disposition method.
  • the infrared cut-off filter 301 can be arranged above the fingerprint identification module.
  • the infrared cut-off filter 301 is suspended above the fingerprint identification module, and can be fixed to the edge area of the fingerprint identification module by means of a bracket and/or an adhesive layer, or can be fixed under the display screen.
  • This application implements
  • the specific fixing method is not limited, and it only needs to be located between the display screen and the fingerprint identification module.
  • the infrared cut-off filter 301 is suspended above the fingerprint identification module, which can prevent the reflection of the optical signal between the filter and the metal layer to form stray light.
  • the structure of the embodiment of the present application can reduce the generation of stray light, improve the quality of the fingerprint image, and further improve the overall performance of the fingerprint identification device.
  • the basic imaging principle of the fingerprint identification device in the embodiment of the present application and the at least two diaphragm layers therein are briefly introduced above.
  • the structure of the fingerprint identification device in the embodiment of the present application is discussed in detail below with reference to FIGS. 3 to 9 . .
  • N light-transmitting holes may be provided in at least one target diaphragm layer of the at least two diaphragm layers, and The N pixel units under the diaphragm layer correspond one-to-one, wherein N is a positive integer greater than 1.
  • N light-transmitting holes may be provided in the bottom diaphragm layer among the at least two diaphragm layers, corresponding to N pixel units one-to-one.
  • one or more layers of the at least one target diaphragm layer is a first diaphragm layer.
  • other diaphragm layers are all second diaphragm layers.
  • M light-passing holes may be set, where 1 ⁇ M ⁇ N, and M is a positive integer, the embodiment of the present application M is not specifically limited.
  • the number of light-transmitting holes in the upper diaphragm layer is less than or equal to the number of light-transmitting holes in the lower diaphragm layer.
  • the aperture of the light-transmitting hole in the upper diaphragm layer is larger than the aperture of the light-transmitting hole in the lower diaphragm layer.
  • the pore diameter decreases sequentially to the bottom.
  • the light-passing holes are all circular holes.
  • circular holes are used for light-passing holes, which can ensure the symmetry of optical signals entering the light-passing holes. to ensure image quality.
  • one aperture is provided in the top aperture layer, and N apertures are provided in other aperture layers except the top aperture layer, so as to form N light guides. light channel.
  • N light-passing holes are also set in the top diaphragm layer, that is, in this example, each of the at least two diaphragm layers is provided with N number of apertures. through holes to form N light guide channels.
  • the arrangement of the apertures can also be in other ways.
  • the other aperture layers only have N apertures.
  • a light-passing hole is set to form N light-guiding channels.
  • the embodiments of the present application do not specifically limit the specific arrangement of the light-transmitting holes in the at least two diaphragm layers, and it is only necessary to form N light-guiding channels.
  • the fingerprint identification unit 302 at least two diaphragm layers are three diaphragm layers, and a light-passing hole is provided in the top diaphragm layer 320 located at the uppermost layer.
  • the intermediate diaphragm layer 340 and the bottom diaphragm layer are both provided with a plurality of light through holes corresponding to the plurality of pixel units.
  • the filter material in the non-light aperture area of the top diaphragm layer 320 is located at the edge portion of the microlens 310 to block stray light at the edge portion of the microlens 310 .
  • Reasonably increasing the aperture of the clear hole in the first diaphragm layer 320 helps to increase the overall amount of light entering and improve the imaging quality.
  • the filter material in the non-light-through hole region of the intermediate diaphragm layer 340 is used to further absorb and block other stray light, and the plurality of light-through holes therein are used to form a plurality of light guide channels corresponding to a plurality of pixel units.
  • the filter material in the non-light hole area of the bottom diaphragm layer 350 is used to absorb or transmit the stray light reflected by the uppermost metal layer of the chip where the pixel unit is located (for example, the metal circuit layer 335 in FIG. 3 ).
  • the light-passing holes cooperate with the light-passing holes on the upper layer to form multiple light-guiding channels with higher directional accuracy, which can further improve the imaging quality.
  • the three diaphragm layers may all be first diaphragm layers, and the non-light aperture areas thereof are used to absorb visible light.
  • the non-light aperture areas of the three diaphragm layers may all be visible light. cut-off filter layer.
  • the non-light-transmitting hole regions of the three-layer diaphragm layers may be all infrared light-transmitting visible light-cutting filter layers. If this solution is adopted, the non-light-transmitting hole region of the bottom layer diaphragm layer 350 at the bottom layer can absorb or transmit stray light to a greater extent, which is helpful to improve the imaging quality to a greater extent.
  • one or two layers of the three diaphragm layers are the first diaphragm layers.
  • the intermediate diaphragm layer 340 of the three diaphragm layers is the first diaphragm layer, and/or the bottom diaphragm layer is the first diaphragm layer, so as to have a good light blocking effect and form a guide light channel.
  • the intermediate diaphragm layer 340 is a first diaphragm layer, for example, infrared light transmits a visible light cut filter layer, and the top diaphragm layer 320 and the intermediate diaphragm layer 350 are second diaphragm layers, such as a blue diaphragm Floor.
  • the filter material of the top diaphragm layer 320 blocks most of the visible light in the wavelength band, only part of the pixel insensitive light is transmitted, and the filter material of the intermediate diaphragm layer 340 blocks all the light. visible light, and form a plurality of light guide channels, the filter material of the bottom diaphragm layer 350 further blocks the stray light transmitted by the micro lens to the pixel unit, and absorbs the stray light reflected by the metal layer of the chip where the pixel unit is located, improving the image quality.
  • the bottom diaphragm layer 350 needs to be disposed close to the metal layer of the chip to improve the effect of absorbing stray light, for example, it is disposed at 1 ⁇ m to 3 ⁇ m above the chip.
  • FIG. 6 shows the relevant structural parameters of the three diaphragm layers when at least two diaphragm layers are three diaphragm layers.
  • the diameter of the microlens 310 is D. It can be understood that if the microlens 310 is a spherical microlens, the If the lower surface of the microlens 310 is circular, the diameter D of the microlens 310 may be the diameter of the circular lower surface of the microlens 310 . If the microlens 310 is an aspherical microlens, the diameter D of the microlens 310 may be the maximum diameter of the lower surface of the microlens 310 .
  • the height of the optical path between the lower surface of the microlens 310 and the upper surface of the sensor chip 330 is H
  • the height of the optical path between any diaphragm layer and the upper surface of the sensor chip 330 is h.
  • the aperture d of the clear hole in the diaphragm layer is in the range of (1 ⁇ 0.3) ⁇ D ⁇ h/H.
  • the diameter of the aperture in the bottom diaphragm layer 350 is d3, and the optical path height between the bottom diaphragm layer 350 and the upper surface of the sensor chip 330 is h3, then d3 is at (1 ⁇ 0.3) ⁇ D ⁇
  • the diameter of the light-passing hole in the intermediate diaphragm layer 340 is d2
  • the optical path height between the intermediate diaphragm layer 340 and the upper surface of the sensor chip 330 is h2
  • d2 is at (1 ⁇ 0.3) ⁇ D ⁇ h2/H
  • the diameter of the aperture in the top diaphragm layer 320 is d1
  • the optical path height between the top diaphragm layer 320 and the upper surface of the sensor chip 330 is h1
  • d1 is at (1 ⁇ 0.3) ⁇ D ⁇ h1/H.
  • the optical path height h3 between the bottom diaphragm layer 350 and the upper surface of the sensor chip 330 can be designed to be between 0 and H/3, and the intermediate diaphragm layer 340 is distanced from the sensor chip 330
  • the optical path height h2 between the upper surfaces can be designed to be between H/5 and 2H/3
  • the optical path height h1 between the top diaphragm layer 320 and the upper surface of the sensor chip 330 can be designed to be between H/2 and H.
  • the bottom diaphragm layer is located below the intermediate diaphragm layer, and the intermediate diaphragm layer is located below the top diaphragm layer.
  • the optical path height h3 between the bottom diaphragm layer 350 and the upper surface of the sensor chip 330 is H/3
  • the middle layer diaphragm layer is set above the bottom diaphragm layer.
  • the optical path height h2 between the diaphragm layer 340 and the upper surface of the sensor chip 330 can be designed to be between H/3 and 2H/3.
  • the optical path height h3 between the bottom diaphragm layer 350 and the upper surface of the sensor chip 330 can be designed to be between 0 and H/3;
  • the optical path height h2 between them can be designed to be between H/5 and 2H/3;
  • FIG. 6 only illustrates the situation when at least two diaphragm layers are three diaphragm layers, and when at least two diaphragm layers are other numbers of diaphragm layers, any one of the diaphragm layers is
  • the size of the light-passing hole in the layer and the position of the diaphragm layer can be referred to the above description, which will not be repeated here.
  • FIG. 7 shows a schematic top view of a fingerprint identification unit 302 in FIG. 3 .
  • the fingerprint identification unit 302 includes 4 pixel units as an example for description.
  • the fingerprint identification unit 302 may further include 2 pixel units or 3 pixel units, or even more A pixel unit, which is not limited in this embodiment of the present application.
  • the four pixel units in the fingerprint identification unit 302 are a first pixel unit 331 , a second pixel unit 332 , a third pixel unit 333 and a fourth pixel unit 334 respectively.
  • the light-transmitting holes in at least two diaphragm layers form four light-guiding channels in different directions, and the photosensitive areas in the four pixel units are respectively used to receive the light-guiding channels passing through the four light-guiding channels. 4 target fingerprint optical signals of the optical channel.
  • one 11# through hole 321 is formed in the top diaphragm layer 320 , and four through holes are formed in each of the intermediate diaphragm layer 340 and the bottom diaphragm layer 350 .
  • the four through holes on the intermediate diaphragm layer 340 are respectively 21# through holes 341, 22# through holes 342, 23# through holes 343 and 24# through holes 344, on the bottom diaphragm layer 350
  • the four light holes are 31# light hole 351, 32# light hole 352, 33# light hole 353 and 34# light hole 354 respectively.
  • the above-mentioned 11# light-passing holes 321, 21# light-passing holes 341 and 31# light-passing holes 351 form a first light guide channel, and the first target fingerprint light signal in the first direction is transmitted to the first pixel through the first light guide channel Unit 331.
  • the above-mentioned 11# light hole 321, 22# light hole 342 and 32# light hole 352 form a second light guide channel, and the second target fingerprint light signal in the second direction is transmitted to the second light guide channel through the second light guide channel.
  • the second pixel unit 332 The second pixel unit 332 .
  • the above-mentioned 11# light hole 321, 23# light hole 343 and 33# light hole 353 form a third light guide channel, and the third target fingerprint light signal in the third direction is transmitted to the third pixel through the third light guide channel Unit 333.
  • the above-mentioned 11# light hole 321, 24# light hole 344 and 34# light hole 354 form a fourth light guide channel, and the fourth target fingerprint light signal in the fourth direction is transmitted to the fourth pixel through the fourth light guide channel unit 334.
  • the direction of the above-mentioned light guide channel may be the direction of the center line of all or part of the light-through holes on the light guide channel, or the direction of the light guide channel may be a direction similar to the direction of the center line, for example, light guide
  • the direction of the channel is within ⁇ 5° of the direction of the center line.
  • the direction of the light guide channel is the same as or similar to the direction of the target fingerprint light signal it receives.
  • FIG. 8 shows another schematic top view of a fingerprint identification unit 302 in FIG. 3 .
  • the structure of the fingerprint identification unit 302 in FIG. 8 is similar to the structure of the fingerprint identification unit 302 in FIG. 7 above, and the related solutions can be described above.
  • the difference between the fingerprint identification unit in FIG. 7 and FIG. 8 is that the positions of the light-passing holes in the three-layer diaphragm layers in FIG. 8 are different from the positions of the light-pass holes in the three-layer diaphragm layers in FIG. 7 above.
  • the angle between the connection line and the vertical direction corresponding to the center of the 21# through hole 341 of the first pixel unit 331 is the first angle.
  • the bottom diaphragm layer 350 corresponds to the first pixel.
  • the included angle between the line connecting the center of the 31# light hole 351 of the unit 331 and the center of the 21# light hole 341 corresponding to the first pixel unit 331 in the intermediate diaphragm layer 340 and the vertical direction is the second angle, then the The first angle is smaller than the second angle.
  • the vertical direction is the direction perpendicular to the plane where the display screen is located
  • the horizontal direction is the direction parallel to the plane where the display screen is located.
  • the angle of the first target fingerprint light signal received by the first light guide channel in FIG. 7 is smaller than the angle of the first target fingerprint light signal received by the first light guide channel in FIG. 8 .
  • the angle of the target fingerprint light signal received by other light guide channels in FIG. 7 is also smaller than the angle of the target fingerprint light signal received by other light guide channels in FIG. 8 .
  • the target fingerprint light signal with a large angle can be received, which is conducive to the detection of dry fingers and reduces the optical path height.
  • the aperture diameters of the light-transmitting holes in the above-mentioned light-guiding channel decrease sequentially from top to bottom.
  • the apertures of the 11# light holes 321 , 21# light holes 341 and 31# light holes 351 decrease sequentially from top to bottom.
  • the above-mentioned light-passing holes may be located at any position below the microlens 310, aiming to form any four light-guiding channels, and the angles between the four light-guiding channels in different directions and the display screen can be completely The same, may not be exactly the same.
  • the first pixel unit 331 , the second pixel unit 332 , the third pixel unit 333 and the fourth pixel unit 334 corresponding to the microlens 310 may also be located at any position below the microlens 310 , and are intended to receive the light passing through four different directions.
  • Target fingerprint light signals in four different directions of the light guide channel.
  • each of the four pixel units is provided with a first photosensitive area 3311 , a second photosensitive area 3321 , a third photosensitive area 3331 and a fourth photosensitive area 3341 .
  • the photosensitive areas in the four pixel units only occupy a small part of the area in the pixel units, so as to meet the requirements of receiving light signals.
  • the center of the first photosensitive area 3311 may be located at the bottom of the first light guide channel, for example, the center of the first photosensitive area 3311 may be located at the connection line of a plurality of light-passing holes in the first light guide channel superior. Similarly, the centers of the photosensitive regions in other pixel units may also be located at the bottom of their corresponding light guide channels.
  • the first target fingerprint light signal forms a first light spot on the first pixel unit 331 through the first light guide channel.
  • the area 3311 may completely cover the above-mentioned first light spot.
  • the photosensitive regions in other pixel units can also completely cover the light spot formed by the target fingerprint light signal.
  • the first pixel unit 331 can be a quadrilateral area, its length and width are L and W respectively, where W ⁇ L, W and L are both positive numbers, the first pixel unit 331
  • the length and width of the first photosensitive region 3311 are both greater than or equal to 0.1 ⁇ W.
  • the sizes of the other three pixel units and the photosensitive area in the four pixel units may also satisfy the above conditions correspondingly.
  • the photosensitive area in the pixel unit is small, but it fully receives the fingerprint light signal after passing through the light guide channel, which meets the fingerprint imaging requirements.
  • the wiring of the unit provides enough space, reduces the process requirements, and improves the efficiency of process manufacturing, and other areas can be used to set other circuit structures, which can improve the signal processing capability of the pixel unit.
  • the center of the area where the four pixel units are located coincides with the center of the microlens in the vertical direction, and the four photosensitive areas in the four pixel units are offset from four The center setting of the pixel unit.
  • the 4 photosensitive areas are not only offset from the center of the pixel unit, but also offset in the direction away from the center of the microlens, so that the angle of the target fingerprint light signal received by the 4 photosensitive areas can be increased, thereby further reducing The thickness of the small fingerprint recognition unit.
  • the four photosensitive areas are respectively located at the four corners of the area where the four pixel units are located.
  • the four photosensitive regions may also be located at the centers of the four pixel units, respectively.
  • the four pixel units may be directed away from the center of the microlens. Offset (the center of the area where the four pixel units are located does not coincide with the center of the microlens in the vertical direction), the angle of the target fingerprint light signal received by the four photosensitive areas is increased, and the thickness of the fingerprint identification unit is reduced.
  • the photosensitive areas in the four pixel units only occupy a small part of the pixel units. In another possible implementation, the photosensitive areas in the four pixel units occupy most of the pixel units. area to improve the dynamic range of the pixel unit.
  • the photosensitive areas in the four pixel units also cover other areas.
  • the photosensitive regions in the four pixel units occupy most of the area of the pixel units.
  • the first photosensitive area 3311 in the first pixel unit 331 occupies more than 95% of the area of the first pixel unit 331, or the respective photosensitive areas in other pixel units occupy more than 95% of the area.
  • the photosensitive area of the pixel unit is increased, which can improve the full well capacity of the pixel unit and the dynamic range of the pixel unit, thereby improving the overall performance of the pixel unit and realizing the high dynamic range imaging of the fingerprint identification device. (high dynamic range imaging, HDR).
  • HDR high dynamic range imaging
  • four pixel units may be arranged at any position below the microlens, and the four pixel units form a pixel area of a quadrilateral area, and the center point of the pixel area and the center of the microlens are vertically coincident or not. coincide.
  • the 4 photosensitive areas can be set at any position in the 4 pixel units, aiming to receive the target fingerprint light signal passing through the four channels. The specific location in is not limited.
  • one microlens corresponds to multiple pixel units, and the multiple pixel units respectively receive fingerprint light signals in multiple directions that are condensed by the microlens and pass through multiple light guide channels.
  • the fingerprint light signals are respectively received by the plurality of pixel units.
  • the amount of light entering the fingerprint identification device can be increased, the exposure time can be reduced, and the field of view of the fingerprint identification device can be increased.
  • the angle of the fingerprint light signal received by the photosensitive areas in the plurality of pixel units is determined by the relative positional relationship between the plurality of photosensitive areas and the microlenses , if the photosensitive area is farther away from the center of the microlens, the angle of the fingerprint light signal received by the photosensitive area is larger.
  • the photosensitive area can receive a large-angle fingerprint light signal, which further improves the identification problem of dry fingers, and can further reduce the thickness of the optical path in the fingerprint identification unit, thereby reducing the The thickness of the fingerprint identification device is small, and the process cost is reduced.
  • the diaphragm layer in the embodiment of the present application has lower cost and higher processing precision than the traditional vinyl material. Improve the control accuracy of the light guide channel and improve the overall performance of the fingerprint identification device.
  • the technical solutions of the embodiments of the present application can improve the overall light input of the fingerprint identification device, improve the identification problem of dry fingers, reduce the thickness of the optical path, comprehensively improve the performance of the fingerprint identification device, and also improve the manufacturing of the fingerprint identification device.
  • the process accuracy and process cost are reduced, so that the fingerprint identification device in the embodiment of the present application has wider application scenarios at low cost and is beneficial to the development of light and thin electronic equipment in which it is located.
  • the target fingerprint light signals in multiple directions received by the fingerprint identification unit 302 are all light signals inclined relative to the display screen, or one target fingerprint light signal in the target fingerprint light signals in multiple directions is perpendicular to the display screen.
  • Oblique optical signals, other target fingerprint optical signals are optical signals oblique to the display screen.
  • the directions of the plurality of light guide channels in different directions formed in the at least two diaphragm layers are all directions inclined with respect to the display screen.
  • the direction of one light guide channel among the plurality of light guide channels in different directions is a direction perpendicular to the display screen, and the directions of the other light guide channels are directions inclined relative to the display screen.
  • the angle of the target fingerprint light signal in the above multiple directions may be between 10° and 45°.
  • the optical path height of the fingerprint identification device can be reasonably controlled within 30 ⁇ m, and the duty cycle of the microlens array can be maximized.
  • At least two diaphragm layers are three diaphragm layers, and optionally, at least two diaphragm layers may also be two layers Aperture layer.
  • FIG. 9 shows a schematic cross-sectional view of another fingerprint identification device.
  • a fingerprint identification unit 302 it only includes the top diaphragm layer 370 and the bottom diaphragm layer 380.
  • the top diaphragm layer 370 and the bottom diaphragm layer 380 can also be the first diaphragm layer, for example, the non-light aperture areas thereof can both be infrared light-transmitting visible light cut-off filter layers.
  • the top diaphragm layer 370 may be a second diaphragm layer, for example, its non-pass aperture area is a blue filter layer
  • the bottom diaphragm layer 380 is a first diaphragm layer, for example, its non-pass aperture area is a first diaphragm layer.
  • the aperture area is for infrared light to pass through the visible light cut-off filter layer.
  • the non-light hole area of the bottom diaphragm layer 380 is used to block visible light and form four light guide channels, and also to absorb stray light signals reflected from the underlying metal layer.
  • the solution of this embodiment can further reduce the cost of the fingerprint identification device by reducing the number of diaphragm layers on the premise of ensuring the imaging quality.
  • the optical path height between the lower surface of the microlens 310 and the upper surface of the sensor chip 330 is H
  • the distance between the bottom diaphragm layer 380 and the upper surface of the sensor chip 330 is between H/5 and 2H/3, and the distance between the top diaphragm layer 370 and the upper surface of the sensor chip 330 is H/2 to H between.
  • the bottom diaphragm layer is located below the top interlayer diaphragm layer.
  • the distance between the bottom diaphragm layer 380 and the upper surface of the sensor chip 330 is 2H/3, in order to meet the above design conditions, when the bottom interlayer diaphragm layer is arranged above the bottom diaphragm layer, the top diaphragm layer
  • the distance between the diaphragm layer 370 and the upper surface of the sensor chip 330 can be designed to be between 2H/3 and H.
  • the distance between the bottom diaphragm layer 380 and the upper surface of the sensor chip 330 is between H/5 and 2H/3, or the distance between the top diaphragm layer 370 and the upper surface of the sensor chip 330 is between H/5 and 2H/3.
  • the distance is between H/2 and H.
  • the difference between the fingerprint identification device in FIG. 9 and the fingerprint identification device in FIG. 3 is only in the number of diaphragm layers, and the top diaphragm layer 370 in FIG. 9 may be the top diaphragm layer in FIG. 3 . 320 , the middle layer diaphragm layer 340 of the bottom diaphragm layer in FIG. 9 , other structures and related technical solutions of the fingerprint identification device in FIG. 9 can refer to the descriptions in FIGS.
  • At least two diaphragm layers may also be four or more diaphragm layers.
  • additional settings may be added between the top diaphragm layer 320 and the intermediate diaphragm layer 340 , and/or between the intermediate diaphragm layer 340 and the bottom diaphragm layer 350 . More diaphragm layers to reduce stray light and improve the effect of fingerprint imaging.
  • the number of light-passing holes on each light-guiding channel is equal to that of the diaphragm layer.
  • more light-transmitting holes may be formed on the light-guiding channel.
  • a plurality of light through holes corresponding to the plurality of light guide channels are also provided.
  • the sensor chip 330 is provided with a metal circuit layer 335 located above the four pixel units, and the metal circuit layer 335 is formed with corresponding to four pixel units.
  • the four light-passing holes can be circular holes, and the four light-passing holes are located below the four light-passing holes in the above-mentioned bottom diaphragm layer 350, which are different from the above-mentioned three-layer diaphragm layers.
  • the light-passing holes in the above-mentioned 4 light guide channels together form the above-mentioned 4 light-guiding channels, and the light-passing holes in the metal circuit layer 335 will not change the directions of the above-mentioned 4 target fingerprint optical signals passing through the 4 light-guiding channels, and further block the fingerprint recognition. effect of stray light and interfering light.
  • the light-passing hole corresponding to the first pixel unit 331 is the 41# light-passing hole 3351
  • the light-passing hole corresponding to the second pixel unit 332 is the 42# light-passing hole 3352
  • corresponding to The light-passing hole of the third pixel unit 333 is 43# light-passing hole 3353
  • the light-passing hole corresponding to the fourth pixel unit 334 is 44# light-passing hole 3354.
  • the centers of the four light-transmitting holes in the metal circuit layer 335 may be located on a connecting line between the centers of the light-transmitting holes in the at least two diaphragm layers, or may also be located within a preset range around the connecting lines.
  • the 11# light hole 321, the 21# light hole 341 and the 31# light hole 351 form the first light guide channel, corresponding to the first pixel unit 331, the 11# light hole 321, 21# light hole
  • the centers of 341 and 31# through holes 351 are located on the first straight line, and the centers of 41# through holes 3351 in the metal circuit layer 335 corresponding to the first pixel unit 331 are also located on the above-mentioned first straight line, or 41 #The center of the light-transmitting hole 3351 may also be located within a preset range around the first straight line.
  • the diameters of the four light-passing holes in the metal circuit layer 335 may be smaller than the diameters of the light-passing holes in the bottom diaphragm layer in the at least two diaphragm layers.
  • the diameters of the four light-passing holes in the metal circuit layer 335 may be smaller than the diameters of the four light-passing holes in the third diaphragm layer 350 .
  • the diameters of the four light-passing holes in the metal circuit layer 335 may be smaller than the diameters of the four light-passing holes in the second diaphragm layer 340 .
  • the light guiding effect of the light guiding channel can be further improved, so as to improve the fingerprint identification effect.
  • the fingerprint identification unit 302 is except for the microlens 310 and the three diaphragm layers (the top diaphragm layer 320 , the middle diaphragm layer 340 , and the bottom diaphragm layer 350 ) described above.
  • the fingerprint identification unit 302 may also include :
  • the first buffer layer 311 and the second buffer layer 351 the first buffer layer 311 is disposed between the microlens 310 and the top diaphragm layer 320 for connecting the microlens 310 and the top diaphragm layer 320 .
  • the second buffer layer 351 is disposed between the sensor chip 330 and the bottom diaphragm layer 350 for connecting the sensor chip 330 and the bottom diaphragm layer 350 .
  • the first buffer layer 311 is grown on the top diaphragm layer 320 , and the first buffer layer 311 is not only formed on the upper surface of the top diaphragm layer 320 , but also formed in the through holes in the top diaphragm layer 320 , for example, formed in the 11# through hole 321 in FIG. 3 .
  • the second buffer layer 351 can be grown on the protective layer and on the second buffer layer 351 Fabrication of the bottom stop layer 350 continues above.
  • first buffer layer 311 and the second buffer layer 351 are both transparent media, including but not limited to transparent organic polymer materials, and the refractive index thereof includes but is not limited to about 1.55.
  • a first transparent medium layer 361 may also be formed between the top diaphragm layer 320 and the intermediate diaphragm layer 340 , and a first transparent medium layer 361 may also be formed between the intermediate diaphragm layer 340 and the bottom diaphragm layer 350 .
  • the first transparent medium layer 361 is used to connect the top diaphragm layer 320 and the intermediate diaphragm layer 340, and control the optical path height between the top diaphragm layer 320 and the intermediate diaphragm layer 340, so as to control the light guide channel and the target The angle of the fingerprint light signal.
  • a first transparent medium layer 361 is grown on its surface.
  • the first transparent dielectric layer 361 is formed not only on the upper surface of the intermediate diaphragm layer 340, but also on the intermediate layer Among the light-transmitting holes in the diaphragm layer 340, for example, 21# light-through holes 341, 22#-light holes 342, 23#-light holes 343 and 24#-light holes 344 in FIG. 3 and FIG. 5 are formed.
  • the second transparent medium layer 362 is used to connect the intermediate diaphragm layer 340 and the bottom diaphragm layer 350, and to control the optical path height between the intermediate diaphragm layer 340 and the bottom diaphragm layer 350, so as to further adjust and control the light guide channel and the angle of the target fingerprint light signal.
  • a second transparent medium layer 362 is grown on its surface.
  • the second transparent medium layer 362 is not only formed on the upper surface of the bottom diaphragm layer 350, but also formed on the bottom diaphragm layer Among the light-passing holes in 350, for example, 31# light-passing holes 351, 32# light-passing holes 352, 33#-lighting holes 353 and 34#-lighting holes 354 are formed in FIG. 3 and FIG. 5 .
  • first transparent medium layer 361 and the second transparent medium layer 362 are also transparent mediums, including but not limited to transparent organic polymer materials, the refractive index of which can be the same as that of the first buffer layer 311 and the first buffer layer 311 and the first buffer layer 311.
  • the refractive indices of the two buffer layers 351 are similar (the difference between the refractive indices is less than a preset threshold), for example, the refractive indices of the first transparent medium layer 361 and the second transparent medium layer 362 may also be about 1.55.
  • the fingerprint identification unit 302 may also include:
  • the first buffer layer 311 and the second buffer layer 351 are disposed between the microlenses 310 and the top diaphragm layer 370 for connecting the microlenses 310 and the top diaphragm layer 370 .
  • the second buffer layer 351 is disposed between the sensor chip 330 and the bottom diaphragm layer 380 for connecting the sensor chip 330 and the bottom diaphragm layer 380 .
  • a first transparent medium layer 361 may also be formed between the top diaphragm layer 370 and the bottom diaphragm layer 380 .
  • the design of each layer structure in the fingerprint identification unit 302 and its related parameters are used to optimize the fingerprint image quality and reduce the thickness of the fingerprint identification device after a large number of experimental verifications.
  • the ratio of the aperture of the clear hole (for example, the 11# clear hole 321 ) to the period of the microlens is within a predetermined threshold to balance the amount of incoming light and block stray light.
  • the sizes and positions of the light-passing holes in the at least two diaphragm layers except the top diaphragm layer are designed to ensure that they smoothly transition to the inside of the sensor chip along the center of receiving light to ensure imaging quality.
  • the curvature radius of the microlens is designed so that the fingerprint can be better imaged in the imaging area of the sensor chip, that is, the diameter of the diffuse spot imaged by the fingerprint object-side image point in the sensor chip is as small as possible.
  • the basic structure of the fingerprint identification device 300 in the present application is described above. Further, by introducing the processing method of the pixel value in the fingerprint identification device 300 below, the fingerprint image can be avoided to generate moiré fringes. While improving the fingerprint image quality, the image processing speed is improved to improve the user experience.
  • the fingerprint identification unit 302 includes four pixel units for illustration.
  • the fingerprint identification device 300 includes a plurality of fingerprint identification units 302 , and each fingerprint identification unit includes 4 pixel units, then all the pixel units can form a pixel array of the fingerprint identification device 300 .
  • FIG. 10 shows a schematic diagram of a pixel array 303 in a fingerprint identification device 300 .
  • the number “1” represents the first pixel unit 331
  • the number “2” represents the second pixel unit 332
  • the number “3” represents the third pixel unit 333
  • the number “4” represents the fourth pixel unit 333.
  • the plurality of first pixel units 331 , the plurality of second pixel units 332 , the plurality of third pixel units 333 , and the plurality of fourth pixel units 334 are not in phase with each other. adjacent.
  • FIG. 10 is only a schematic arrangement diagram of a pixel array 303.
  • the first pixel unit 331, the second pixel unit 332, the third pixel unit 333 and the fourth pixel unit 334 The relative positional relationship can be transformed.
  • the position of the first pixel unit 331 in the figure may also be the second pixel unit 332, the third pixel unit 333, or the fourth pixel unit 334, which is not limited in this embodiment of the present application.
  • a plurality of first pixel units 331 receive target fingerprint light signals in one direction, and the target fingerprint light signals are used to form a first fingerprint image of a finger.
  • the plurality of second pixel units 332 receive the fingerprint light signal in another direction, and the fingerprint light signal is used to form a second fingerprint image of the finger.
  • the plurality of third pixel units 333 receive the fingerprint light signals in the third direction, and the fingerprint light signals are used to form a third fingerprint image of the finger.
  • the plurality of fourth pixel units 334 receive the fingerprint light signal in the fourth direction, and the fingerprint light signal is used to form a fourth fingerprint image of the finger.
  • the first fingerprint image, the second fingerprint image, the third fingerprint image and the fourth fingerprint image can be used for fingerprint identification alone, or any two or three fingerprint images can be reconstructed, and the reconstructed fingerprint images can be reconstructed.
  • the image is fingerprinted.
  • each pixel unit receives the target fingerprint light signal in its corresponding direction to generate an original pixel value.
  • the schematic diagram of the pixel array 303 shown in FIG. 10 can also be regarded as the formation of the original pixel value. Schematic of the original image.
  • the original pixel values formed by the pixel array 303 need to undergo physical pixel synthesis and/or digital pixel synthesis (binning), etc., to finally form the above-mentioned first fingerprint image, second fingerprint image, third fingerprint image and Fourth fingerprint image.
  • FIG. 11 shows a schematic diagram of an image processing method.
  • 1# is a schematic diagram of the original image formed by the pixel array 303 in FIG. 10 .
  • the number “1” represents the original pixel value generated by the first pixel unit 331
  • the number “2” represents the original pixel value generated by the second pixel unit 332
  • the number “3” represents the third pixel unit.
  • the original pixel value generated by 333, and the number "4" represents the original pixel value generated by the fourth pixel unit 334 described above.
  • the fingerprint identification device 300 includes a first summing and averaging circuit, a second summing and averaging circuit, a third summing and averaging circuit, and a fourth summing and averaging circuit, which are used to compare the original pixel values. Perform physical pixel synthesis.
  • the first summing and averaging circuit is configured to be connected to a plurality of first pixel units 331 in the pixel array 302 through metal wires, and to sum and average the original pixel values of every X1 ⁇ X2 first pixel units 331 , forming a pixel value in the first intermediate fingerprint image.
  • the second summing and averaging circuit is used for connecting to a plurality of second pixel units 332 in the pixel array 302 through metal wires, and summing and averaging the original pixel values of every X1 ⁇ X2 second pixel units 332 , forming a pixel value in the second intermediate fingerprint image.
  • the third summing and averaging circuit is used for connecting to a plurality of third pixel units 333 in the pixel array 302 through metal wires, and summing and averaging the original pixel values of every X1 ⁇ X2 third pixel units 333 to form a third summation and averaging circuit.
  • the fourth summing and averaging circuit is used for connecting to the plurality of fourth pixel units 334 in the pixel array 302 through metal wires, and summing and averaging the original pixel values of every X1 ⁇ X2 fourth pixel units 334 to form a fourth summation and averaging circuit.
  • the X1 ⁇ X2 first pixel units 331 may be adjacent X1 ⁇ X2 pixel units among the plurality of first pixel units 331 of the pixel array 302 , for example, may be 2 ⁇ 2 four first pixel units 331 .
  • X1 and X2 are not specifically limited in this embodiment of the present application.
  • first intermediate fingerprint image, second intermediate fingerprint image, third intermediate fingerprint image, and fourth intermediate fingerprint image may refer to Figure 2# in FIG. 11 .
  • the pixel value in the first intermediate fingerprint image (represented as “1'” in FIG. 11 ) is 2 ⁇ 2 original pixel values (represented as “1” in FIG. 11 ) of the first pixel unit 331 after summing and averaging
  • the pixel value (denoted as “2'” in FIG. 11 ) in the second intermediate fingerprint image is 2 ⁇ 2 original pixel values (denoted as “2” in FIG. 11 ) of the first pixel unit 332 ) obtained after summing and averaging
  • the pixel value in the third intermediate fingerprint image (represented as "3'" in Fig. 11 ) is 2 ⁇ 2 original pixel values of the first pixel unit 333 (represented as "3'" in Fig.
  • the pixel value in the fourth intermediate fingerprint image (represented as "4'" in FIG. 11 ) is the 2 ⁇ 2 original pixel values of the first pixel unit 334 (represented in FIG. 11 ). "4") is obtained after summing and averaging.
  • further digital pixel synthesis may be performed on the above-mentioned four intermediate fingerprint images, so as to further reduce the number of pixel values and improve the image processing efficiency.
  • the process of digital pixel synthesis is not implemented by analog hardware circuits, but can be implemented by digital circuits.
  • the fingerprint identification device may include a processing unit for the first intermediate fingerprint image, the second intermediate fingerprint image, the third The intermediate fingerprint image and the fourth intermediate fingerprint image are subjected to digital pixel synthesis, and the processing unit includes but is not limited to an image signal processor (image signal processor, ISP).
  • ISP image signal processor
  • every Y1 ⁇ Y2 pixel value in the above-mentioned first intermediate fingerprint image is used for digital pixel synthesis to form a pixel value in the first fingerprint image; every Y1 ⁇ Y2 pixel value in the second intermediate fingerprint image The value is used for digital pixel synthesis to form a pixel value in the second fingerprint image; every Y1 ⁇ Y2 pixel value in the third intermediate fingerprint image is used for digital pixel synthesis to form a pixel value in the third fingerprint image; Every Y1 ⁇ Y2 pixel value in the fourth intermediate fingerprint image is used for digital pixel synthesis to form one pixel value in the fourth fingerprint image; wherein, Y1 and Y2 are positive integers.
  • first fingerprint image second fingerprint image
  • third fingerprint image fourth fingerprint image
  • fourth fingerprint image reference may be made to Figure 3# in FIG. 11 .
  • the pixel value in the first fingerprint image (represented as “1” in FIG. 11 ) is 2 ⁇ 2 pixel values in the first intermediate fingerprint image (represented as “1’” in FIG. 11 ) after the summation and average
  • the pixel value in the second fingerprint image (represented as “2" in Fig. 11 ) is 2 ⁇ 2 pixel values in the second intermediate fingerprint image (represented as "2'” in Fig. 11 ) ) after the summation and averaging
  • the pixel value in the third fingerprint image (represented as “3” in FIG. 11 ) is 2 ⁇ 2 pixel values in the third intermediate fingerprint image (represented as “3” in FIG.
  • the pixel values in the fourth fingerprint image (represented as "4" in Figure 11) are 2 ⁇ 2 pixel values in the fourth intermediate fingerprint image (represented in Figure 11 as "4'") is obtained by summing and averaging.
  • the four fingerprint images can also be processed by other subsequent images, for example, the four fingerprint images are interleaved and reconstructed into one fingerprint image and then used for fingerprint identification, or, the four fingerprint images are used for fingerprint identification. Any one of the fingerprint images can be used for fingerprint recognition alone.
  • the embodiments of this application only enumerate the pixel synthesis process in the image processing process, and other image processing includes but is not limited to the image processing process in the prior art, which will not be described here.
  • the average value of multiple pixel values is used as the synthesized pixel value.
  • the maximum value of multiple pixel values The minimum value or the calculated value obtained according to other calculation methods is used as the synthesized pixel value, which is not specifically limited in this embodiment of the present application.
  • low-pass filtering can be performed on the four intermediate fingerprint images to weaken the influence of moire fringes.
  • the above-mentioned digital pixel synthesis processing is performed, which can further optimize the fingerprint image quality while reducing the amount of pixel data.
  • the fingerprint identification apparatus 300 may further include a low-pass filter (low-pass filter, LPF), which is used to perform the above-mentioned low-pass filtering process.
  • LPF low-pass filter
  • the distance between the pixel values of two adjacent pixel units that receive light signals in the same direction is L, in other words , the spatial sampling period of the fingerprint identification device 300 is L.
  • the spatial sampling period L of the fingerprint identification device 300 can also be understood as the arrangement period of multiple fingerprint identification units, or the arrangement period of microlenses in the microlens array formed by multiple fingerprint identification units, or the arrangement period of multiple fingerprint identification units.
  • the arrangement period of pixel unit groups in the formed pixel array.
  • the spatial sampling period of the fingerprint identification device 300 is changed from L to X ⁇ L.
  • only the original pixel values in the original image may be physically synthesized.
  • the spatial sampling period of the fingerprint identification device is related to the spatial imaging period of the display screen.
  • the spatial sampling period of the fingerprint identification device 300 is less than half of the spatial imaging period of the display screen, which can make The spatial sampling period of the fingerprint identification device satisfies the Nyquist sampling law relative to the spatial imaging period of the display screen, that is, moire fringes can be avoided in the fingerprint image, and accordingly, the fingerprint identification effect can be improved.
  • the spatial imaging period of the display screen may be the period of the pixel unit of the display screen.
  • the spatial imaging period of the display screen can also be the ratio of the pixel unit period of the display screen to the scaling factor K of the optical imaging system, where K is the image displayed in the photosensitive area of the pixel unit in the fingerprint identification device and the pixel unit in the photosensitive area. The scaling between images acquired within the region.
  • the pixel unit period of existing high-pixel density screens on the market that is, the spatial imaging period of the above-mentioned display screens is mostly above 45um.
  • the screen structure period is more complicated.
  • the fingerprint module is required to be within the installation tolerance of ⁇ 2.5° due to the installation tolerance, so that the period of the moire fringes is outside the fingerprint period.
  • the spatial sampling period of the fingerprint identification device is between 25-50um, there may not be an appropriate tolerance angle for a screen with dense pixel arrangement or a larger angle needs to be rotated to keep the Moiré fringe period away from the fingerprint period. Since the parameters of different screens may be different, the rotation angle of the fingerprint identification device will be different for different screens, which makes it impossible to normalize the product.
  • the spatial sampling rate period of the fingerprint identification device is made to be less than half of the spatial imaging period of the display screen, for example, less than 20um, it is possible to avoid Moire fringes in the fingerprint image, Accordingly, the fingerprint recognition effect is improved.
  • the versatility of the fingerprint module can also be increased, and the Moiré fringe problem in the fingerprint image caused by almost all screens on the market can be solved without rotation.
  • the spatial sampling rate of the fingerprint identification device in the embodiment of the present application not only depends on the original spatial sampling rate of the fingerprint identification device, that is, not only depends on the arrangement period of the pixel units receiving the same direction, but also depends on the subsequent Pixel synthesis process.
  • the optimal implementation is adopted to solve the Moiré fringe problem in the fingerprint image, improve the quality of the fingerprint image, and at the same time improve the image processing speed.
  • Embodiments of the present application further provide an electronic device, which may include a display screen and the fingerprint identification device of the above embodiments of the present application, wherein the fingerprint identification device is disposed below the display screen to realize off-screen optical fingerprint identification.
  • the electronic device can be any electronic device with a display screen.
  • the display screen can be the display screen in the above description, such as an OLED display screen or other display screen, and the relevant description of the display screen can refer to the description about the display screen in the above description, which is not repeated here for brevity.
  • a layer of foam may be provided below the display screen, and at least one opening may be provided on the foam layer above the fingerprint identification device, and the at least one The reflected light signal is transmitted to the fingerprint recognition device.
  • a fingerprint is a diffuse reflector that reflects light in all directions.
  • the display screen displays green, cyan or white light spots
  • the fingerprint identification device uses the green, cyan or white light source to perform fingerprint identification.
  • a specific optical path in the fingerprint identification device can be used to make the optical sensing pixel array in the fingerprint identification device receive inclined light signals in multiple directions, and the processing unit in the fingerprint identification device or the processing unit connected with the fingerprint identification device The reconstructed fingerprint image can be obtained through the algorithm, and then the fingerprint recognition can be carried out.
  • a gap may or may not exist between the fingerprint recognition device and the display screen.
  • the fingerprint identification device may output the collected image to a dedicated processor of a computer or a dedicated processor of an electronic device, so as to perform fingerprint identification.
  • the processor in this embodiment of the present application may be an integrated circuit chip, which has a signal processing capability.
  • each step of the above method embodiments may be completed by a hardware integrated logic circuit in a processor or an instruction in the form of software.
  • the above-mentioned processor can be a general-purpose processor, a digital signal processor (Digital Signal Processor, DSP), an application specific integrated circuit (Application Specific Integrated Circuit, ASIC), an off-the-shelf programmable gate array (Field Programmable Gate Array, FPGA) or other available Programming logic devices, discrete gate or transistor logic devices, discrete hardware components.
  • DSP Digital Signal Processor
  • ASIC Application Specific Integrated Circuit
  • FPGA Field Programmable Gate Array
  • a general purpose processor may be a microprocessor or the processor may be any conventional processor or the like.
  • the steps of the method disclosed in conjunction with the embodiments of the present application may be directly embodied as executed by a hardware decoding processor, or executed by a combination of hardware and software modules in the decoding processor.
  • the software modules may be located in random access memory, flash memory, read-only memory, programmable read-only memory or electrically erasable programmable memory, registers and other storage media mature in the art.
  • the storage medium is located in the memory, and the processor reads the information in the memory, and completes the steps of the above method in combination with its hardware.
  • the fingerprint identification in this embodiment of the present application may further include a memory, and the memory may be a volatile memory or a nonvolatile memory, or may include both volatile memory and nonvolatile memory.
  • the non-volatile memory may be a read-only memory (Read-Only Memory, ROM), a programmable read-only memory (Programmable ROM, PROM), an erasable programmable read-only memory (Erasable PROM, EPROM), an electrically programmable read-only memory (Erasable PROM, EPROM). Erase programmable read-only memory (Electrically EPROM, EEPROM) or flash memory.
  • Volatile memory may be Random Access Memory (RAM), which acts as an external cache.
  • RAM random access memory
  • SRAM Static RAM
  • DRAM Dynamic RAM
  • SDRAM Synchronous DRAM
  • SDRAM double data rate synchronous dynamic random access memory
  • Double Data Rate SDRAM DDR SDRAM
  • enhanced SDRAM ESDRAM
  • synchronous link dynamic random access memory Synchlink DRAM, SLDRAM
  • Direct Rambus RAM Direct Rambus RAM
  • the disclosed system, apparatus and method may be implemented in other manners.
  • the apparatus embodiments described above are only illustrative.
  • the division of the units is only a logical function division. In actual implementation, there may be other division methods.
  • multiple units or components may be combined or Can be integrated into another system, or some features can be ignored, or not implemented.
  • the shown or discussed mutual coupling or direct coupling or communication connection may be through some interfaces, indirect coupling or communication connection of devices or units, and may be in electrical, mechanical or other forms.
  • the units described as separate components may or may not be physically separated, and components displayed as units may or may not be physical units, that is, may be located in one place, or may be distributed to multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution in this embodiment.
  • each functional unit in each embodiment of the present application may be integrated into one processing unit, or each unit may exist physically alone, or two or more units may be integrated into one unit.
  • the functions, if implemented in the form of software functional units and sold or used as independent products, may be stored in a computer-readable storage medium.
  • the technical solutions of the present application can be embodied in the form of software products in essence, or the parts that contribute to the prior art or the parts of the technical solutions, and the computer software products are stored in a storage medium , including several instructions for causing a computer device (which may be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of the present application.
  • the aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (Read-Only Memory, ROM), random access memory (Random Access Memory, RAM), magnetic disk or optical disk and other media that can store program codes .

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Abstract

一种指纹识别装置和电子设备，能够提高指纹识别装置的性能且降低其成本。该指纹识别装置包括：指纹识别模组，包括：微透镜；至少两层光阑层，至少两层光阑层中的每一层光阑层中设置通光孔以形成不同方向的多个导光通道，在至少两层光阑层中，至少一层第一光阑层的非通光孔区域用于吸收可见光，至少一层第二光阑层的非通光孔区域用于透过非像素敏感光并吸收像素敏感光；多个像素单元，设置在至少两层光阑层下方并位于多个导光通道的底部；其中，从显示屏上方的手指反射或散射后返回的指纹光信号通过微透镜会聚后，不同方向的多个目标指纹光信号分别经过多个导光通道传输至多个像素单元，该多个目标指纹光信号用于检测手指的指纹信息。

Description

指纹识别装置和电子设备 技术领域
本申请涉及光学指纹技术领域，并且更具体地，涉及一种指纹识别装置和电子设备。
背景技术
随着手机行业的高速发展，屏下光学指纹技术方案的应用越来越普及，终端厂商对于厚度更薄、性能更低、成本更低的方案有着强烈的需求。
在一些相关技术中，指纹识别装置中的微透镜阵列位于像素阵列的正上方，且一个微透镜对应一个像素单元，即微透镜阵列中的每一个微透镜将接收到的光线聚焦至同一微透镜对应的像素单元中，且多个像素单元呈阵列排列。采用该技术方案，指纹识别装置的整体进光量小，曝光时间长，整体成像质量较差，且对干手指的识别性能不佳。与此同时，指纹识别装置中的光路厚度厚，增加光路的加工难度以及成本，也不利于指纹识别装置轻薄化的发展。
因此，如何综合提高指纹识别装置的性能并降低其成本，是一项亟待解决的问题。
发明内容
本申请实施例提供了一种指纹识别装置和电子设备，能够在提高指纹识别装置的性能的同时降低其成本。
第一方面，提供了一种指纹识别装置，适用于显示屏的下方以实现屏下光学指纹识别，该指纹识别装置包括：指纹识别模组，包括多个指纹识别单元，该多个指纹识别单元中的每个指纹识别单元包括：微透镜；至少两层光阑层，设置在该微透镜下方，该至少两层光阑层中的每一层滤光层中设置通光孔以形成不同方向的多个导光通道，在该至少两层光阑层中，至少一层第一光阑层的非通光孔区域用于吸收可见光，至少一层第二光阑层的非通光孔区域用于透过非像素敏感光并吸收像素敏感光；多个像素单元，设置在该至少两层光阑层下方，且该多个像素单元对该非像素敏感光的响应度小于等于第一预设阈值，对该像素敏感光的响应度大于等于第二预设阈值，该第一预 设阈值小于该第二预设阈值，该多个像素单元分别位于该多个导光通道的底部；其中，从该显示屏上方的手指反射或散射后返回的指纹光信号通过该微透镜会聚后，其中不同方向的多个目标指纹光信号分别经过该多个导光通道传输至该多个像素单元，该多个目标指纹光信号用于检测该手指的指纹信息。
通过本申请的技术方案，一个微透镜对应多个像素单元，且多个像素单元分别接收经过该微透镜会聚并通过多个导光通道的多个方向的指纹光信号，该多个方向的指纹光信号分别被多个像素单元接收。相对于一个微透镜对应一个像素单元的技术方案，能够增大提高指纹识别装置的进光量，减小曝光时间，增大指纹识别装置的视场。
此外，多个像素单元接收的指纹光信号的角度由该像素单元与微透镜的相对位置关系决定，通过灵活设置像素单元的位置，可以使得像素单元可以接收大角度的指纹光信号，进一步改善干手指的识别问题，并且能够进一步降低指纹识别单元中光路的厚度，从而减小指纹识别装置的厚度、降低工艺成本。
另外，本方案中的光阑层较于传统的黑胶材料的成本较低，且加工精度高，能够提高产品的一致性以及生产良率，另外，由于该光阑层中的通光孔的大小以及位置均可以精确控制，能够提高对导光通道的控制精度，从而提高成像质量，与此同时，本方案中的最底层光阑层还能吸收像素单元上方的杂散光，进一步提高成像质量，从而提升指纹识别装置的整体性能。
综上，通过上述方案，在提高指纹识别装置的整体进光量、改善干手指的识别问题、降低光路厚度，综合提升指纹识别装置性能的同时，提高指纹识别装置的制造工艺精度、良率并且降低工艺成本，使得本申请实施例中的指纹识别装置在低成本具有更广泛的应用场景且有利于其所在电子设备的轻薄化发展。
在一种可能的实施方式中，该第一光阑层的非通光孔区域还用于透过红外光，该第一光阑层的非通光孔区域为红外光透过可见光截止滤光层。
在一种可能的实施方式中，该指纹识别装置还包括：红外截止滤光片，设置于该显示屏至该指纹识别模组中的该多个像素单元之间的光路中。
在一种可能的实施方式中，该红外截止滤光片设置于该指纹识别模组上方。
在本实施方式中，将红外截止滤光片设置于指纹识别模组上方，可以防止光信号在滤光片与多个像素单元所在芯片的金属层之间的反射形成杂散光，与此同时，还可以避免环境干扰光进入像素单元，换言之，采用本申请实施例的结构，可以减少杂散光和环境干扰光，提高指纹图像的质量，进一步提高指纹识别装置的整体性能。
在一种可能的实施方式中，该非像素敏感光为第一颜色光，该像素敏感光包括第二颜色光，该第二光阑层中的非通光孔区域用于透过该第一颜色光并吸收该第二颜色光。
在一种可能的实施方式中，该第一颜色光为蓝光，该第二光阑层的非通光孔区域为蓝色滤光材料形成的滤光层或者为紫色滤光材料形成的滤光层。
在一种可能的实施方式中，该显示屏用于在该手指按压区域发出该第二颜色光，该第二颜色光从该手指反射或散射后返回的第二颜色指纹光通过该微透镜会聚后，其中不同方向的多个第二颜色目标指纹光信号分别经过该多个导光通道传输至该多个像素单元，该多个第二颜色目标指纹光信号用于检测该手指的指纹信息。
在一种可能的实施方式中，该第二颜色光为绿光或者青光。
在一种可能的实施方式中，该第一预设阈值小于等于10％，该第二预设阈值大于等于70％。
在一种可能的实施方式中，该至少一层第二光阑层的非通光孔区域对该像素敏感光的吸收率大于第三预设阈值。
在一种可能的实施方式中，该第三预设阈值大于等于70％。
在一种可能的实施方式中，该至少两层光阑层为三层光阑层，该三层光阑层中的中间层光阑层为该第一光阑层，该三层光阑层中的顶层光阑层和底层光阑层为该第二光阑层。
在一种可能的实施方式中，该三层光阑层中的中间层光阑层中设置有与该多个像素单元分别一一对应的多个通光孔，以形成该多个导光通道。
在一种可能的实施方式中，该三层光阑层中的顶层光阑层中设置有一个通光孔，且该三层光阑层中的底层光阑层中设置有与该多个像素单元分别一一对应的多个通光孔，以形成该多个导光通道。
在一种可能的实施方式中，该多个像素单元形成于传感器芯片中，该微透镜的下表面至该传感器芯片上表面之间的光路高度为H，
该三层光阑层中的底层光阑层至该传感器芯片上表面之间的距离在0至H/3之间，该三层光阑层中的中间层光阑层至该传感器芯片上表面之间的距离在H/5至2H/3之间，该至少两层光阑层中的顶层光阑层至该传感器芯片上表面之间的距离在H/2至H之间。
在一种可能的实施方式中，该至少两层光阑层为两层光阑层，该两层光阑层中的底层光阑层为该第一光阑层，该两层光阑层中的顶层光阑层为该第二光阑层。
在一种可能的实施方式中，该两层光阑层中的底层光阑层中设置有与该多个像素单元分别一一对应的多个通光孔，以形成该多个导光通道。
在一种可能的实施方式中，该两层光阑层中的顶层光阑层中设置有一个通光孔，以形成该多个导光通道。
在一种可能的实施方式中，该多个像素单元形成于传感器芯片中，该微透镜的下表面至该传感器芯片上表面之间的光路高度为H，
该至少两层光阑层中的底层光阑层至该传感器芯片上表面之间的距离在H/5至2H/3之间，该至少两层光阑层中的顶层光阑层至该传感器芯片上表面之间的距离在H/2至H之间。
在一种可能的实施方式中，该多个导光通道中的通光孔由上至下孔径依次减小。
在一种可能的实施方式中，该多个像素单元形成于传感器芯片中，该微透镜的直径为D，该微透镜的下表面至该传感器芯片上表面之间的光路高度为H，该至少两层光阑层中的一层光阑层与该传感器芯片上表面之间的光路高度为h，该一层光阑层中通光孔的孔径d处于(1±0.3)×D×h/H的范围之间。
在一种可能的实施方式中，该指纹识别装置还包括：金属线路层，该金属线路层中设置有多个通光孔，该多个通光孔一一对应的设置于该多个像素单元上方，并一一对应的设置于该多个导光通道下方；
该多个目标指纹光信号通过该多个导光通道传导至该金属线路层中的该多个通光孔，并通过该多个通光孔传导至该多个像素单元。
在一种可能的实施方式中，该多个导光通道中第一导光通道中的通光孔的中心位于第一直线上，该第一导光通道对应的该金属线路层中的通光孔也位于该第一直线上。
在一种可能的实施方式中，该至少两层光阑层中的通光孔以及该金属线路层中的通光孔均为圆形通光孔。
在一种可能的实施方式中，该金属线路层中的通光孔的直径小于该至少两层光阑层中底层光阑层中的通光孔的直径。
在一种可能的实施方式中，该每个指纹识别单元还包括：透明介质层，用于连接该至少两层光阑层。
在一种可能的实施方式中，该每个指纹识别单元还包括：第一缓冲层，用于连接该微透镜与该至少两层光阑层中的顶层光阑层；第二缓冲层，用于连接该传感器芯片与该至少两层光阑层中的底层光阑层。
在一种可能的实施方式中，该透明介质层与该第一缓冲层的折射率之差，以及该透明介质层与该第二缓冲层的折射率之差均在预设阈值之内。
在一种可能的实施方式中，该多个像素单元为四个像素单元，该四个像素单元形成四边形区域的像素区域，该像素区域的中心点与该微透镜的中心在垂直方向上重合或者不重合。
在一种可能的实施方式中，该多个导光通道为四个导光通道，该四个导光通道的方向中至少三个导光通道的方向相对于该显示屏倾斜。
采用本申请实施方式的方案，通过设置导光通道的方向，可以使得四个像素单元中的像素单元分别接收倾斜方向的指纹光信号，倾斜方向的指纹光信号能够改善干手指的指纹识别问题，且能够减小指纹识别装置的厚度。
在一种可能的实施方式中，该四个导光通道与垂直于该显示屏方向的夹角在10至45°之间。
综合考虑通过导光通道的光信号强度以及倾斜度，采用本申请实施方式的方案，能够在改进干手指识别问题的同时，满足光信号的强度，且控制整个指纹识别装置的光路厚度。
在一种可能的实施方式中，该四个像素单元中分别包括四个感光区域，该四个感光区域分别位于该四个导光通道的底部。
在一种可能的实施方式中，该四个感光区域中的至少一个感光区域偏离于其所在的像素单元的中心设置。
在一种可能的实施方式中，该至少一个感光区域向远离于该微透镜中心的方向偏离。
在一种可能的实施方式中，该四个像素单元形成四边形的像素区域，该 四个感光区域分别位于该像素区域的四角。
在一种可能的实施方式中，其特征在于，该指纹识别模组包括多组该四个像素单元；多组该四个像素单元中的多个第一像素单元接收的光信号用于形成该手指的第一指纹图像，多组该四个像素单元中的多个第二像素单元接收的光信号用于形成该手指的第二指纹图像，多组该四个像素单元中的多个第三像素单元接收的光信号用于形成该手指的第三指纹图像，多组该四个像素单元中的多个第四像素单元接收的光信号用于形成该手指的第四指纹图像，该第一指纹图像、该第二指纹图像、该第三指纹图像和该第四指纹图像中的一张或者多张图像用于进行指纹识别。
在一种可能的实施方式中，该多个第一像素单元中每X1×X2个第一像素单元连接至第一求和平均电路进行物理像素合成，形成第一中间指纹图像中的一个像素值；该多个第二像素单元中每X1×X2个第二像素单元连接至第二求和平均电路进行物理像素合成，形成第二中间指纹图像中的一个像素值；该多个第三像素单元中每X1×X2个第三像素单元连接至第三求和平均电路进行物理像素合成，形成第三中间指纹图像中的一个像素值；该多个第四像素单元中每X1×X2个第四像素单元连接至第四求和平均电路进行物理像素合成，形成第四中间指纹图像中的一个像素值；其中，X1和X2为正整数。
在一种可能的实施方式中，该指纹识别装置还包括：该第一求和平均电路，该第二求和平均电路，该第三求和平均电路以及该第四求和平均电路。
在一种可能的实施方式中，该第一中间指纹图像中每Y1×Y2个像素值用于进行数字像素合成，形成该第一指纹图像中的一个像素值；该第二中间指纹图像中每Y1×Y2个像素值用于进行数字像素合成，形成该第二指纹图像中的一个像素值；该第三中间指纹图像中每Y1×Y2个像素值用于进行数字像素合成，形成该第三指纹图像中的一个像素值；该第四中间指纹图像中每Y1×Y2个像素值用于进行数字像素合成，形成该第四指纹图像中的一个像素值；其中，Y1和Y2为正整数。
在一种可能的实施方式中，该指纹识别装置还包括：处理单元，用于对该第一中间指纹图像、该第二中间指纹图像、该第三中间指纹图像以及该第四中间指纹图像进行数字像素合成。
采用本实施方式的方案，能够减小指纹图像处理过程中的像素数量，提 高指纹识别的速度，且在本实施方式中，若多个像素单元中有若干个像素单元故障，该多个像素单元仍然可以通过像素合成输出得到像素值，不会影响指纹图像的形成以及指纹识别的效果。
在一种可能的实施方式中，该第一中间指纹图像、该第二中间指纹图像、该第三中间指纹图像以及该第四中间指纹图像用于经过低通滤波处理后进行数字像素合成。
在一种可能的实施方式中，该指纹识别装置还包括：低通滤波器，用于对该第一中间指纹图像、该第二中间指纹图像、该第三中间指纹图像以及该第四中间指纹图像进行低通滤波处理。
采用本实施方式的方案，可以降低指纹图像中莫尔条纹的影响。
在一种可能的实施方式中，X1＝X2＝Y1＝Y2＝2。
在一种可能的实施方式中，该多个第一像素单元之间互不相邻，该多个第二像素单元之间互不相邻，该多个第三像素单元之间互不相邻，且该多个第四像素单元之间互不相邻。
在一种可能的实施方式中，该显示屏中发光像素的排列周期为P1，该指纹识别装置的空间采样周期P2＜P1/2。
采用本实施方式的方案，可以使得指纹识别装置的空间采样周期相对显示屏的空间成像周期满足奈奎斯特采样定律，即，能够避免指纹图像中出现莫尔条纹，相应的，提升指纹识别效果。
在一种可能的实施方式中，该指纹识别装置的空间采样周期根据该多个指纹识别单元的排列周期以及像素合成方式计算得到。
在一种可能的实施方式中，该多个指纹识别单元的排列周期在12μm至20μm之间。
在一种可能的实施方式中，该多个指纹识别单元中每个指纹识别单元的光路厚度在30μm以内。
在一种可能的实施方式中，该指纹识别装置和该显示屏之间的距离为0至1mm。
第二方面，提供一种电子设备，包括：显示屏；以及第一方面或第一方面中任一种可能的实施方式中的指纹识别装置，该指纹识别装置设置于该显示屏下方，以实现屏下光学指纹识别。
在一种可能的实施方式中，该显示屏用于在指纹检测区域显示绿色、青 色或者白色光斑，该指纹识别装置用于接收绿色、青色或者白色目标指纹光信号，以检测手指的指纹信息。
在一种可能的实施方式中，该指纹识别装置和该显示屏之间的距离为0至1mm。
在电子设备中设置上述指纹识别装置，通过提升指纹识别装置的指纹识别性能且降低指纹识别装置的成本，从而提升该电子设备的指纹识别性能且降低电子设备的成本。
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图1是本申请实施例所适用的电子设备的结构示意图。
图2是本申请实施例提供的一种指纹识别装置的示意性截面图。
图3是本申请实施例提供的另一指纹识别装置的示意性截面图。
图4是图3中指纹识别装置的示意性俯视图。
图5是根据本申请实施例的一种电子设备的示意性结构图。
图6是根据本申请实施例的指纹识别单元中三层光阑层的相关结构参数示意图。
图7是图3中一个指纹识别单元的一种示意性俯视图。
图8是图3中一个指纹识别单元的另一种示意性俯视图。
图9是本申请实施例提供的另一指纹识别装置的示意性截面图。
图10是根据本申请实施例的一种指纹识别装置中的像素阵列的示意图。
图11是根据本申请实施例的一种图像处理方法的示意图。
具体实施方式
下面将结合附图，对本申请实施例中的技术方案进行描述。
应理解，本申请实施例可以应用于光学指纹系统，包括但不限于光学指纹识别系统和基于光学指纹成像的产品，本申请实施例仅以光学指纹系统为例进行说明，但不应对本申请实施例构成任何限定，本申请实施例同样适用于其他采用光学成像技术的系统等。
作为一种常见的应用场景，本申请实施例提供的光学指纹系统可以应用在智能手机、平板电脑以及其他具有显示屏的移动终端或者其他电子设备；更具体地，在上述电子设备中，指纹识别装置可以具体为光学指纹装置，其 可以设置在显示屏下方的局部区域或者全部区域，从而形成屏下(Under-display)光学指纹系统。或者，该指纹识别装置也可以部分或者全部集成至电子设备的显示屏内部，从而形成屏内(In-display)光学指纹系统。
如图1所示为本申请实施例可以适用的电子设备的结构示意图，该电子设备10包括显示屏120和光学指纹装置130，其中，该光学指纹装置130设置在显示屏120下方的局部区域。该光学指纹装置130包括光学指纹传感器，该光学指纹传感器包括具有多个光学感应单元131的感应阵列133，该感应阵列133所在区域或者其感应区域为光学指纹装置130的指纹检测区域103。如图1所示，指纹检测区域103位于显示屏120的显示区域之中。在一种替代实施例中，光学指纹装置130还可以设置在其他位置，比如显示屏120的侧面或者电子设备10的边缘非透光区域，并通过光路设计来将显示屏120的至少部分显示区域的光信号导引到光学指纹装置130，从而使得指纹检测区域103实际上位于显示屏120的显示区域。
应当理解，指纹检测区域103的面积可以与光学指纹装置130的感应阵列的面积不同，例如通过例如透镜成像的光路设计、反射式折叠光路设计或者其他光线汇聚或者反射等光路设计，可以使得光学指纹装置130的指纹检测区域103的面积大于光学指纹装置130感应阵列的面积。在其他替代实现方式中，如果采用例如光线准直方式进行光路引导，光学指纹装置130的指纹检测区域103也可以设计成与该光学指纹装置130的感应阵列的面积基本一致。
因此，使用者在需要对电子设备进行解锁或者其他指纹验证的时候，只需要将手指按压在位于显示屏120的指纹检测区域103，便可以实现指纹输入。由于指纹检测可以在屏内实现，因此采用上述结构的电子设备10无需其正面专门预留空间来设置指纹按键(比如Home键)，从而可以采用全面屏方案，即显示屏120的显示区域可以基本扩展到整个电子设备10的正面。
作为一种可选的实现方式，如图1所示，光学指纹装置130包括光检测部分134和光学组件132，该光检测部分134包括感应阵列以及与该感应阵列电性连接的读取电路及其他辅助电路，其可以在通过半导体工艺制作在一个芯片(Die)，比如光学成像芯片或者光学指纹传感器，该感应阵列具体为光探测器(Photo detector)阵列，其包括多个呈阵列式分布的光探测器，该光探测器可以作为上述的光学感应单元；该光学组件132可以设置在光检测部 分134的感应阵列的上方，其可以具体包括导光层或光路引导结构以及其他光学元件，该导光层或光路引导结构主要用于从手指表面反射回来的反射光导引至感应阵列进行光学检测。
在具体实现上，光学组件132可以与光检测部分134封装在同一个光学指纹部件。比如，该光学组件132可以与该光学检测部分134封装在同一个光学指纹芯片，也可以将该光学组件132设置在该光检测部分134所在的芯片外部，比如将该光学组件132贴合在该芯片上方，或者将该光学组件132的部分元件集成在上述芯片之中。
其中，光学组件132的导光层或者光路引导结构有多种实现方案，比如，该导光层可以具体为在半导体硅片制作而成的准直器(Collimator)层，其具有多个准直单元或者微孔阵列，该准直单元可以具体为小孔，从手指反射回来的反射光中，垂直入射到该准直单元的光线可以穿过并被其下方的光学感应单元接收，而入射角度过大的光线在该准直单元内部经过多次反射被衰减掉，因此每一个光学感应单元基本只能接收到其正上方的指纹纹路反射回来的反射光，从而感应阵列便可以检测出手指的指纹图像。
在另一种实施例中，导光层或者光路引导结构也可以为光学透镜(Lens)层，其具有一个或多个透镜单元，比如一个或多个非球面透镜组成的透镜组，其用于将从手指反射回来的反射光汇聚到其下方的光检测部分134的感应阵列，以使得该感应阵列可以基于该反射光进行成像，从而得到该手指的指纹图像。可选地，该光学透镜层在该透镜单元的光路中还可以形成有针孔，该针孔可以配合该光学透镜层扩大光学指纹装置的视场，以提高光学指纹装置130的指纹成像效果。
在其他实施例中，导光层或者光路引导结构也可以具体采用微透镜(Micro-Lens)层，该微透镜层具有由多个微透镜形成的微透镜阵列，其可以通过半导体生长工艺或者其他工艺形成在光检测部分134的感应阵列上方，并且每一个微透镜可以分别对应于感应阵列的其中一个感应单元。并且，微透镜层和感应单元之间还可以形成其他光学膜层，比如介质层或者钝化层，更具体地，微透镜层和感应单元之间还可以包括具有微孔的挡光层，其中该微孔形成在其对应的微透镜和感应单元之间，挡光层可以阻挡相邻微透镜和感应单元之间的光学干扰，并使得感应单元所对应的光线通过微透镜汇聚到微孔内部并经由该微孔传输到该感应单元以进行光学指纹成像。应当理解， 上述光路引导结构的几种实现方案可以单独使用也可以结合使用，比如，可以在准直器层或者光学透镜层下方进一步设置微透镜层。当然，在准直器层或者光学透镜层与微透镜层结合使用时，其具体叠层结构或者光路可能需要按照实际需要进行调整。
作为一种可选的实施例，显示屏120可以采用具有自发光显示单元的显示屏，比如有机发光二极管(Organic Light-Emitting Diode，OLED)显示屏或者微型发光二极管(Micro-LED)显示屏。以采用OLED显示屏为例，光学指纹装置130可以利用OLED显示屏120位于指纹检测区域103的显示单元(即OLED光源)来作为光学指纹检测的激励光源。当手指140按压在指纹检测区域103时，显示屏120向指纹检测区域103上方的目标手指140发出一束光111，该光111在手指140的表面发生反射形成反射光或者经过手指140内部散射而形成散射光，在相关专利申请中，为便于描述，上述反射光和散射光统称为反射光。由于指纹的脊(ridge)与谷(valley)对于光的反射能力不同，因此，来自指纹脊141的反射光151和来自指纹谷142的反射光152具有不同的光强，反射光经过光学组件132后，被光学指纹装置130中的感应阵列134所接收并转换为相应的电信号，即指纹检测信号；基于该指纹检测信号便可以获得指纹图像数据，并且可以进一步进行指纹匹配验证，从而在电子设备10实现光学指纹识别功能。
在其他实施例中，光学指纹装置130也可以采用内置光源或者外置光源来提供用于进行指纹检测的光信号。在这种情况下，该光学指纹装置130可以适用于非自发光显示屏，比如液晶显示屏或者其他的被动发光显示屏。以应用在具有背光模组和液晶面板的液晶显示屏为例，为支持液晶显示屏的屏下指纹检测，电子设备10的光学指纹系统还可以包括用于光学指纹检测的激励光源，该激励光源可以具体为红外光源或者特定波长非可见光的光源，其可以设置在液晶显示屏的背光模组下方或者设置在电子设备10的保护盖板下方的边缘区域，而光学指纹装置130可以设置液晶面板或者保护盖板的边缘区域下方并通过光路引导以使得指纹检测光可以到达光学指纹装置130；或者，光学指纹装置130也可以设置在背光模组下方，且背光模组通过对扩散片、增亮片、反射片等膜层进行开孔或者其他光学设计以允许指纹检测光穿过液晶面板和背光模组并到达光学指纹装置130。当采用光学指纹装置130采用内置光源或者外置光源来提供用于进行指纹检测的光信号时， 其检测原理与上面描述内容是一致的。
应当理解的是，在具体实现上，电子设备10还包括透明保护盖板，该盖板可以为玻璃盖板或者蓝宝石盖板，其位于显示屏120的上方并覆盖电子设备10的正面。因为，本申请实施例中，所谓的手指按压在显示屏120实际上是指按压在显示屏120上方的盖板或者覆盖该盖板的保护层表面。
还应当理解，电子设备10还可以包括电路板150，该电路板设置在光学指纹装置130的下方。光学指纹装置130可以通过背胶粘接在电路板150上，并通过焊盘及金属线焊接与电路板150实现电性连接。光学指纹装置130可以通过电路板150实现与其他外围电路或者电子设备10的其他元件的电性互连和信号传输。比如，光学指纹装置130可以通过电路板150接收电子设备10的处理单元的控制信号，并且还可以通过电路板150将来自光学指纹装置130的指纹检测信号输出给电子设备10的处理单元或者控制单元等。
另一方面，在某些实施例中，光学指纹装置130可以仅包括一个光学指纹传感器，此时光学指纹装置130的指纹检测区域103的面积较小且位置固定，因此用户在进行指纹输入时需要将手指按压到指纹检测区域103的特定位置，否则光学指纹装置130可能无法采集到指纹图像而造成用户体验不佳。在其他替代实施例中，光学指纹装置130可以具体包括多个光学指纹传感器；该多个光学指纹传感器可以通过拼接方式并排设置在显示屏120的下方，且该多个光学指纹传感器的感应区域共同构成光学指纹装置130的指纹检测区域103。也即是说，光学指纹装置130的指纹检测区域103可以包括多个子区域，每个子区域分别对应于其中一个光学指纹传感器的感应区域，从而将光学指纹装置130的指纹采集区域103可以扩展到显示屏的下半部分的主要区域，即扩展到手指惯常按压区域，从而实现盲按式指纹输入操作。可替代地，当光学指纹传感器数量足够时，指纹检测区域103还可以扩展到半个显示区域甚至整个显示区域，从而实现半屏或者全屏指纹检测。
还应理解，在本申请实施例中，光学指纹装置中的感应阵列也可以称为像素阵列，感应阵列中的光学感应单元或感应单元也可称为像素单元或者像素。
需要说明的是，本申请实施例中的光学指纹装置也可以称为光学指纹识别模组、指纹识别装置、指纹识别模组、指纹模组、指纹采集装置等，上述术语可相互替换。
图2示出了一种指纹识别装置的示意性截面图。
如图2所示，指纹识别装置200包括微透镜阵列210、至少一层挡光层220、像素阵列230以及滤光片240。
其中，微透镜阵列210位于像素阵列230和至少一层挡光层220的正上方，且一个微透镜211对应一个像素单元231，即微透镜阵列210中的每一个微透镜211将接收到的光线通过至少一层挡光层220的小孔2201聚焦至同一微透镜211对应的像素单元231中。其中，每一个微透镜211接收的光信号主要为经过显示屏上方手指反射或散射后垂直于微透镜阵列210入射的指纹光信号。
如图2所示，像素阵列230形成于衬底201中，像素阵列230中的每个像素单元231中包括感光区域(active area，AA)2311，该感光区域2311可以为光电二极管的感光区域，用于将接收到的指纹光信号转换为对应的电信号值。在像素阵列230上方形成有金属线路层233，其用于传输像素阵列230中每个像素单元231的电信号。
可选地，如图2所示，该金属线路层233上同样形成有小孔，可以用于传输指纹光信号至像素单元231。在该金属线路层233上方，可以形成有保护层234，该保护层234可以包括：硅的氧化物、硅的氮化物和/或硅的氮氧化物。
可以理解的是，图2中的衬底201、像素阵列230、以及金属线路层233和表面的保护层234可以为一种图像传感器芯片中的示意性叠层结构，本申请实施例对具体的图像传感器类型及其具体芯片结构不做限定。
可选地，在该传感器芯片上方，可以直接生长滤光片240，该滤光片240可以为红外截止(IR-cut,IRC)滤光片，用于对环境中红外光、近红外光以及部分红外信号进行截止。在该滤光片240上方，再生长透明介质层以及至少一层挡光层220。在一些实施方式中，该至少一层挡光层220采用黑胶材料，用于吸收和阻挡光信号。
在图2的指纹识别装置200中，微透镜阵列210中的多个微透镜211和像素阵列230中的多个像素单元231一一对应，且像素阵列230中多个像素单元231的感光区域2311呈周期性排列且均匀分布。
但是，像素阵列230的感光区域会受到微透镜阵列210的尺寸的影响，且指纹识别装置200的厚度较大，进而增加了指纹识别装置200的光路的加 工难度、周期以及成本。
此外，在正常生活场景下，例如洗完手、早晨起床、手指抹灰、低温等场景下手指通常较干，其角质层不均匀，其按压在显示屏上时，手指局部区域会出现接触不良。当干手指与显示屏接触不好时，上述指纹识别装置200形成的垂直方向的指纹图像的指纹脊和指纹谷的对比度差，图像模糊到分辨不了指纹纹路，因而，上述指纹识别装置200对于干手指的指纹识别性能较差。
另外，由于滤光片240生长于传感器芯片上方，且滤光片240的表面通常具有较高的反射率，而传感器芯片上层的金属线路层234对光信号也具有较高反射率，因此，光信号容易在滤光片240以及金属线路层234之间相互反射，形成光波导效应，产生较多的杂散光，该杂散光容易进入到像素单元中，影响指纹识别装置的图像质量。
除了上述问题以外，图2中的指纹识别装置200中，采用黑胶材料的至少一层挡光层220的成本较高且加工精度低，即限制了挡光层220中小孔的大小以及位置精度，从而限制指纹识别装置的整体性能。
基于此，本申请提出一种改进的指纹识别装置，能够解决上述指纹识别装置成本高以及性能不佳等问题。
以下，结合图3至图10，详细介绍本申请实施例的指纹识别装置。
需要说明的是，为便于理解，在以下示出的实施例中，相同的结构采用相同的附图标记，并且为了简洁，省略对相同结构的详细说明。
另外，在以下所示出的本申请实施例中的像素单元、微透镜以及光阑层上通光孔的数量和排布方式等仅为示例性说明，而不应对本申请构成任何限定。
图3是本申请实施例提供的一种指纹识别装置300的示意性截面图，图4是本申请实施例提供的一种指纹识别装置300的示意性俯视图。图3可以为沿图4中A-A’方向的截面示意图。
如图3所示，该指纹识别装置300包括：
指纹识别模组，包括多个指纹识别单元302，该多个指纹识别单元302中的每个指纹识别单元包括：
微透镜310；
至少两层光阑层，例如图3中的顶层光阑层320，中间层光阑层340以 及底层光阑层350，该至少两层光阑层设置在该微透镜310下方，且该至少两层光阑层中的每一层光阑层中设置通光孔以形成不同方向的多个导光通道；该至少两层光阑层中，至少一层第一光阑层的非通光孔区域用于吸收可见光，至少一层第二光阑层的非通光孔区域用于透过非像素敏感光；
多个像素单元，例如，图3中示出了其中两个像素单元331和334，该多个像素单元设置在上述至少两层光阑层下方，且该多个像素单元一一对应的分别位于上述多个导光通道的底部，且该多个像素单元对非像素敏感光的响应度小于第一预设阈值；
其中，从显示屏上方的手指反射或散射后返回的指纹光信号通过微透镜会聚后，其中不同方向的多个目标指纹光信号分别经过上述多个导光通道传输至上述多个像素单元，且该多个目标指纹光信号用于检测手指的指纹信息。
在本申请中，对于指纹识别模组中的多个指纹识别单元，在纵向空间上，在一些实施方式中，该多个指纹识别单元中每个指纹识别单元的光路结构相互独立，例如，如图3中示出的两个指纹识别单元，一个指纹识别单元中的微透镜将其接收到的光信号传输至其下方对应的像素单元中。
在另一些实施方式中，该多个指纹识别单元的结构也可以相互交错。例如，一个指纹识别单元中的微透镜可将其接收到的倾斜光信号会聚至相邻的指纹识别单元中的微透镜下方的像素单元。换言之，一个微透镜将接收到的倾斜光信号会聚至与该微透镜相邻的微透镜下方的像素单元。
具体地，在横向空间上，在一些实施方式中，如图4所示，该多个指纹识别单元可以呈方形阵列排列，则多个指纹识别单元中的多个微透镜形成方形排列的微透镜阵列，四个相邻的微透镜的中心构成一个正方形。
在另一些实施方式中，该多个指纹识别单元也可以呈菱形阵列排列，则多个指纹识别单元中的多个微透镜形成菱形排列的微透镜阵列，四个相邻的微透镜的中心构成一个菱形。
可以理解的是，除了上述列举出来的几种方式以外，本申请实施例中的多个指纹识别单元在纵向空间以及横向空间上，还可以以其他任意形式进行排列，本申请实施例其不做具体限定。
具体地，在本申请中，微透镜310可以是各种具有会聚功能的镜头，用于增大视场，增加传输至像素单元的光信号量。该微透镜310的材料可以为 有机材料，例如树脂。可选地，该微透镜310的表面可以为球面或者非球面。该微透镜310可以为圆形透镜或者方形透镜等等，本申请实施例对此不做限定。
可选地，若该微透镜310为圆形微透镜，其制造成本低于方形微透镜，能够降低指纹识别装置整体的制造成本。
具体地，圆形微透镜的直径不大于上述多个像素单元的排列周期。例如，若多个像素单元所在区域为A×B的四边形区域，其中，A≤B，A与B为正整数，则微透镜310的直径小于等于A。
在一些实施方式中，如图4所示，在指纹识别装置中，若多个指纹识别单元呈方形阵列排列，则多个指纹识别单元中的多个微透镜形成方形排列的微透镜阵列。在该方形排列的微透镜阵列中，受制于制造工艺，相邻两个圆形微透镜之间通常存在间隙而不是相切状态，例如，若该间隙宽度为x＝1μm，多个像素单元形成L×L的正方形区域，则圆形微透镜的直径为(L-1)μm，圆形微透镜的圆心在该正方形区域上的正投影位于该正方形区域的中心。
具体地，在本申请中，像素单元可以为一种光电转换单元。可选地，该像素单元可以包括光电二极管(photo diode，PD)以及开关管等等，其中，开关管用于接收控制信号控制光电二极管的工作，并可以用于控制输出光电二极管的电信号。可选地，指纹识别单元302中的多个像素单元可以为四边形像素单元，例如正方形像素单元。
如图3所示，像素单元具体可以采用半导体工艺形成于衬底中，该多个指纹识别单元中的像素单元可以形成像素阵列，该像素阵列通过一层或者多层金属线路层(例如，图3中示出的金属线路层335)进行电连接，该一层或者多层金属线路层、像素阵列以及衬底等可以形成一种图像传感器芯片330，该图像传感器芯片可以为CMOS图像传感器或者也可以为CCD传感器，且可以理解的是，该图像传感器中除了上述金属线路层、像素阵列以及衬底以外，还可以包括必要的介质层或者其它叠层结构，例如，一层或多层金属层之间的介质层，以及最顶层金属层上方的保护层等等，该部分内容可以参见现有技术的相关描述，本申请对此不做详细介绍。
具体地，在本申请中，至少两层光阑层可以为具有透过目标波段光信号且截止非目标波段光信号的滤光材料层，其中设置有通光孔以限制光束实现 成像。
该至少两层光阑层中包括至少一层第一光阑层，该第一光阑层的非通光孔区域用于吸收可见光，作为示例，该第一光阑层可以为红外光透过(IR-pass,IRP)可见光截止滤光层，该红外光透过可见光截止滤光层与指纹识别单元上方的红外光截止滤光层相互结合，可以对全部的可见光以及红外光信号进行截止，从而使得该可见光截止滤光层和红外光截止滤光层的组合能够起到良好的光阻挡作用。
并且，相比于图2中的挡光层220材料为黑胶材料，本申请中的至少一层第一光阑层的成本较低，且加工精度高，能够提高产品的一致性以及生产良率，换言之，该至少一层第一光阑层中的通光孔的大小以及位置均可以精确控制，从而能够提高对导光通道的控制精度，提升指纹识别装置的整体性能。通过本申请的技术方案，在能够保证良好的光阻挡的情况下，能够进一步降低指纹识别装置的成本且提高指纹识别装置的性能。
进一步地，该至少两层光阑层中还包括至少一层第二光阑层，该至少一层第二光阑层用于透过非像素敏感光，该非像素敏感光为像素单元不敏感的光信号，即像素单元对该非像素敏感光的响应度较小或者没有响应，例如小于第一预设阈值。换言之，即使像素单元接收到该非像素敏感光，像素单元不会将该非像素敏感光转换为电信号或者转换的电信号较小。
作为示例，该非像素敏感光可以为第一颜色光，该第一颜色光包括但不限于是蓝光，或者还可以为其它颜色的光信号。
可选地，在本申请实施例中，第一预设阈值可以小于等于10％，像素单元对第一颜色光的响应度小于10％，作为示例，像素单元对于蓝光的量子效率小于10％。
进一步地，该至少一层第二光阑层的非通光孔区域在透过非像素敏感光的同时，还用于吸收像素敏感光，且该至少一层第二光阑层的非通光孔区域对该像素敏感光的吸收率较大，例如，大于第三预设阈值。
与像素非敏感光相对应的，该像素敏感光为像素单元敏感的光信号，即像素单元对该像素敏感光的响应度较大，例如大于第二预设阈值，该第二预设阈值大于上述第一预设阈值。换言之，当像素单元接收到该像素敏感光，像素单元相应于该像素敏感光，并将其转换为对应的电信号。
作为示例，该像素敏感光可以包括第二颜色光，该第二颜色光包括但不 限于是绿光或者青光，或者还可以为其它不同于第一颜色光的光信号。
在一些实施方式中，上述第二预设阈值和第三预设阈值可以大于等于70％，具体地，像素单元对第二颜色光的响应度大于70％，且第二光阑层的非通光孔区域对该第二颜色光的吸收率大于70％，作为示例，像素单元对于绿光的量子效率大于70％，该第二光阑层的非通光孔区域对绿光的吸收率大于70％。
通过上述对第二光阑层的介绍，在本申请实施例中，第二光阑层可以为第二颜色滤光材料组成的光阑层，例如，其可以为蓝色滤光层或者紫色滤光层形成的滤光层，其中的非通光孔区域用于透过蓝光信号并吸收除蓝光以外的光信号。
相比于图2中的挡光层220材料为黑胶材料，本申请中的至少一层第二光阑层同样成本较低，且加工精度高，有利于进一步提高产品的一致性以及生产良率，通过本申请的技术方案，在能够保证良好的光阻挡的情况下，进一步降低指纹识别装置的成本和提升指纹识别装置的性能。
可以理解的是，上述第一预设阈值、第二预设阈值以及第三预设阈值的数值均为示例性说明，本申请实施例对其具体数值不做限定。
在本实施方式中，针对指纹识别单元302中像素单元的响应特性，设计对应的光阑层的组合，能够在降低成本的基础上，降低杂散光对于像素单元的影响，进一步提高成像质量。
并且，在本申请实施例中，指纹识别单元302中的像素单元对绿光或者青光响应度最高，多个指纹识别单元302形成的像素阵列产生的指纹图像质量较好，对比度较高。
更进一步地，针对指纹识别单元302中的像素单元可以对绿光或者青光响应度最高，在进行指纹识别时，光源可以发出绿色或者青色的光信号，可以进一步的减少其他波段的杂散光信号。
当然，光源也可以发出包括绿光信号的其它光信号，例如白光信号等等，本申请实施例对此不做限定。
图5是根据本申请实施例的一种电子设备的示意性结构图。
可选地，如图5所示，若指纹识别装置设置于显示屏120下方，且指纹识别装置在进行指纹识别时，其使用的光源为显示屏120，则在进行指纹识别时，对应于手指按压的位置，或者说指纹识别装置的指纹检测区域处，显 示屏的发光区域121显示绿色、青色或者白色的光斑，以提供指纹识别的光源。
以光源发出绿光信号为例，该绿色光信号从手指反射或散射后返回的绿色指纹光信号通过微透镜会聚后，其中不同方向的多个绿色目标指纹光信号分别经过多个导光通道传输至多个像素单元，该多个绿色目标指纹光信号用于检测手指的指纹信息。
可选地，如图5所示，指纹识别装置300中可以包括红外截止滤光片301，该红外截止滤光片301设置于显示屏120至指纹识别模组中的多个像素单元之间的光路中。
在本申请中，红外截止滤光片301用于防止环境中的红外光信号进入至指纹识别模组中，影响指纹识别结果。进一步的，该红外截止滤光片301还可以防止近红外光信号以及可见光中的部分或者全部红光信号进入至像素单元中，例如该红外截止滤光片301可以用于截止620nm波段以上的红光及红外光进入至像素单元中。
在一种实施方式中，该红外截止滤光片301可以设置在多个像素单元所在图像传感器芯片的表面，其设置方式可以参见图2中的相关描述。
优选地，在另一种实施方式中，如图5所示，该红外截止滤光片301可以设置在指纹识别模组的上方。
可选地，该红外截止滤光片301悬空设置于指纹识别模组上方，其可以利用支架和/或胶层固定于指纹识别模组的边缘区域，也可以固定于显示屏下方，本申请实施例对其具体固定方式不做限定，其只需位于显示屏与指纹识别模组之间即可。
相比于图2中的滤光片240，将红外截止滤光片301悬空设置于指纹识别模组上方，可以防止光信号在滤光片与金属层之间的反射形成杂散光，换言之，采用本申请实施例的结构，可以减少杂散光的生成，提高指纹图像的质量，进一步提高指纹识别装置的整体性能。
上文对本申请实施例的指纹识别装置的基本成像原理以及其中的至少两层光阑层做了一个简单介绍，下面结合图3至图9对本申请实施例中的指纹识别装置的结构做具体论述。
在本申请实施例中，为了在至少两层光阑层中形成N个导光通道，可以在至少两层光阑层的中的至少一层目标光阑层中设置N个通光孔，与光阑层 下方的N个像素单元一一对应，其中，N为大于1的正整数。例如，可以在至少两层光阑层的中的底层光阑层中设置N个通光孔，一一对应于N个像素单元。
可选地，该至少一层目标光阑层中的一层或者多层为第一光阑层。
可选地，在至少两层光阑层中，除了第一光阑层外，其它光阑层均为第二光阑层。
进一步地，除上述目标光阑层外，在至少两层光阑层的其它光阑层中，可以设置M个通光孔，其中1≤M≤N，且M为正整数，本申请实施例对M不做具体限定。
可选地，在至少两层光阑层中，上层光阑层中通光孔的数量小于等于下层光阑层中通光孔的数量。
可选地，在至少两层光阑层中，上层光阑层中通光孔的孔径大于下层光阑层中通光孔的孔径，换言之，在多个导光通道中，通光孔由上至下孔径依次减小。
可选地，在至少两层光阑层中，通光孔均为圆形孔，相比于方形孔或者异形孔，通光孔采用圆形孔，能够保证光信号进入通光孔时的对称性，保证图像成像质量。
作为一种示例，在至少两层光阑层中，顶层光阑层中设置一个通光孔，除了顶层光阑层外，其它光阑层中均设置N个通光孔，以形成N个导光通道。
作为另一种示例，在至少两层光阑层中，顶层光阑层中也设置N个通光孔，即在本示例中，至少两层光阑层中每层光阑层中均设置N个通光孔，以形成N个导光通道。
当然，除了上述两种示例以外，通光孔的设置还可以采用其它方式，例如在至少两层光阑层中，除底层光阑层中设置N个通光孔外，其它光阑层均只设置一个通光孔，以形成N个导光通道。本申请实施例对至少两层光阑层中通光孔的具体设置不做具体限定，旨在形成N个导光通道即可。
在一些实施方式中，如图3所示，在指纹识别单元302中，至少两层光阑层为三层光阑层，其中，位于最上层的顶层光阑层320中设置有一个通光孔，中间层光阑层340和底层光阑层中均设置有对应于多个像素单元的多个通光孔。
具体地，顶层光阑层320的非通光孔区域的滤光材料位于微透镜310的边沿部分，用于阻挡微透镜310边沿部分的杂散光。合理的提升第一光阑层320中通光孔的孔径有助于提升总体进光量，并提升成像质量。
中间层光阑层340的非通光孔区域的滤光材料用于进一步吸收和阻挡其他杂散光，其中的多个通光孔用于形成对应于多个像素单元的多个导光通道。
底层光阑层350的非通光孔区域的滤光材料用于吸收或者透过像素单元所在芯片的最上层金属层(例如图3中的金属线路层335)反射的杂散光，其中的多个通光孔配合上一层的多个通光孔形成方向精度更高的多个导光通道，可以进一步提升成像质量。
一些实施方式中，该三层光阑层可以均为第一光阑层，其非通光孔区域用于吸收可见光，作为示例，该三层光阑层的非通光孔区域可以均为可见光截止滤光层。例如，三层光阑层的非通光孔区域可以均为红外光透过可见光截止滤光层。若采用此方案，则最下层的底层光阑层350的非通光孔区域能够较大程度的吸收或者透过杂散光，有助于较大程度的提高成像质量。
另一些实施方式中，该三层光阑层中的一层或两层为第一光阑层。
具体地，三层光阑层中的中间层光阑层340为第一光阑层，和/或底层光阑层为第一光阑层，以能够起到良好的阻光作用，并形成导光通道。
作为示例，中间层光阑层340为第一光阑层，例如红外光透过可见光截止滤光层，顶层光阑层320和中间层光阑层350为第二光阑层，例如蓝色光阑层。
当光信号经过微透镜310会聚之后，通过顶层光阑层320的滤光材料阻挡大部分波段的可见光，仅透过部分像素非敏感光，在中间层光阑层340的滤光材料处阻挡全部可见光，并形成多个导光通道，在底层光阑层350的滤光材料处进一步阻挡由微透镜传输至像素单元的杂散光，并吸收由像素单元所在芯片的金属层反射的杂散光，提升成像质量。
可以理解的是，底层光阑层350需要靠近于芯片的金属层设置，以提高其吸收杂散光的效果，例如，其设置于芯片上方1μm至3μm处。
图6示出了至少两层光阑层为三层光阑层时，三层光阑层的相关结构参数。
如图6所示，在指纹识别单元302中，多个像素单元形成于传感器芯片 330中，微透镜310的直径为D，可以理解的是，若该微透镜310为球面微透镜，该微透镜310的下表面为圆形，则该微透镜310的直径D可以为该微透镜310圆形下表面的直径。若该微透镜310为非球面微透镜，则该微透镜310的直径D可以为该微透镜310下表面的最大直径。
如图6所示，微透镜310的下表面至传感器芯片330上表面之间的光路高度为H，任意一层光阑层与传感器芯片330上表面之间的光路高度为h，该任意一层光阑层中通光孔的孔径d处于(1±0.3)×D×h/H的范围之间。
例如，图6中，底层光阑层350中通光孔的直径为d3，底层光阑层350距离传感器芯片330上表面之间的光路高度为h3，则d3处于(1±0.3)×D×h3/H之间，类似地，中间层光阑层340中通光孔的直径为d2，中间层光阑层340距离传感器芯片330上表面之间的光路高度为h2，则d2处于(1±0.3)×D×h2/H之间，顶层光阑层320中通光孔的直径为d1，顶层光阑层320距离传感器芯片330上表面之间的光路高度为h1，则d1处于(1±0.3)×D×h1/H之间。
需要说明的是，按照上述通光孔孔径的计算方式，若一层光阑层中形成多个通光孔，多个通光孔之间有交叠，则多个通光孔形成一个大孔径的通光孔。
继续参见图6，在一些实施方式中，底层光阑层350距离传感器芯片330上表面之间的光路高度h3可以设计在0至H/3之间，且中间层光阑层340距离传感器芯片330上表面之间的光路高度h2可以设计在H/5至2H/3之间，且顶层光阑层320距离传感器芯片330上表面之间的光路高度h1可以设计在H/2至H之间。
可以理解的是，在本实施方式中，底层光阑层位于中间层光阑层的下方，且中间层光阑层位于顶层光阑层的下方。作为示例，若底层光阑层350距离传感器芯片330上表面之间的光路高度h3为H/3时，为了满足上述设计条件，并将中间层光阑层设置在底层光阑层上方时，中间层光阑层340距离传感器芯片330上表面之间的光路高度h2可以设计在H/3至2H/3之间。
在另一种实施方式中，底层光阑层350距离传感器芯片330上表面之间的光路高度h3可以设计在0至H/3之间；或者，中间层光阑层340距离传感器芯片330上表面之间的光路高度h2可以设计在H/5至2H/3之间；或者，顶层光阑层320距离传感器芯片330上表面之间的光路高度h1可以设计在 H/2至H之间。
还可以理解的是，上述图6仅示意出至少两层光阑层为三层光阑层时的情况，当至少两层光阑层为其它数量的光阑层时，其中任意一层光阑层中通光孔的大小以及光阑层的位置可以参见上文描述，此处不赘述。
图7中示出了图3中一个指纹识别单元302的一种示意性俯视图。
在本申请实施例中，以指纹识别单元302中包括4个像素单元为例进行说明，可选地，指纹识别单元302中还可以包括2个像素单元或者3个像素单元，乃至更多数量的像素单元，本申请实施例对此不做限定。
如图7所示，该指纹识别单元302中的4个像素单元分别为第一像素单元331，第二像素单元332，第三像素单元333以及第四像素单元334。
对应地，在该指纹识别单元中，至少两层光阑层中的通光孔形成4个不同方向的导光通道，该4个像素单元中的感光区域分别用于分别接收通过该4个导光通道的4个目标指纹光信号。
如图3和图7所示，顶层光阑层320中形成有一个11#通光孔321，在中间层光阑层340以及底层光阑层350中各形成有四个通光孔，具体地，中间层光阑层340上的四个通光孔分别为21#通光孔341，22#通光孔342，23#通光孔343以及24#通光孔344，底层光阑层350上的四个通光孔分别为31#通光孔351，32#通光孔352，33#通光孔353以及34#通光孔354。
上述11#通光孔321、21#通光孔341以及31#通光孔351形成第一导光通道，第一方向的第一目标指纹光信号经过该第一导光通道传输至第一像素单元331。
类似地，上述11#通光孔321、22#通光孔342以及32#通光孔352形成第二导光通道，第二方向的第二目标指纹光信号经过该第二导光通道传输至第二像素单元332。
上述11#通光孔321、23#通光孔343以及33#通光孔353形成第三导光通道，第三方向的第三目标指纹光信号经过该第三导光通道传输至第三像素单元333。
上述11#通光孔321、24#通光孔344以及34#通光孔354形成第四导光通道，第四方向的第四目标指纹光信号经过该第四导光通道传输至第四像素单元334。
可选地，上述导光通道的方向可以为该导光通道上全部或者部分通光孔 中心连线的方向，或者导光通道的方向为与该中心连线方向相近的方向，例如，导光通道的方向与中心连线的方向在±5°之内。在本申请中，导光通道的方向与其接收的目标指纹光信号的方向相同或者相近。
图8中示出了图3中一个指纹识别单元302的另一种示意性俯视图。
图8中指纹识别单元302的结构与上文图7中的指纹识别单元302的结构类似，相关方案可以上文描述。图7与图8中指纹识别单元的差异在于，图8中三层光阑层中的通光孔的位置不同于上文图7中三层光阑层中的通光孔的位置。
以图7和图8中第一像素单元331对应的第一导光通道进行举例说明，若图7中底层光阑层350中对应于第一像素单元331的31#通光孔351中心与中间层光阑层340中对应于第一像素单元331的21#通光孔341中心的连线方向与垂直方向的夹角为第一角度，图8中底层光阑层350中对应于第一像素单元331的31#通光孔351中心与中间层光阑层340中对应于第一像素单元331的21#通光孔341中心的连线方向与垂直方向的夹角为第二角度，则该第一角度的小于该第二角度。在本申请中，垂直方向为垂直于显示屏所在平面的方向，水平方向为平行于显示屏所在平面的方向。
因此，图7中第一导光通道接收的第一目标指纹光信号的角度小于图8中第一导光通道接收的第一目标指纹光信号的角度。类似地，图7中其它导光通道接收的目标指纹光信号的角度也小于图8中其它导光通道接收的目标指纹光信号的角度。
采用图8提供的指纹识别装置，通过设置大角度的导光通道，能够接收较大角度的目标指纹光信号，有利于干手指的检测并降低光路高度。
可选地，上述导光通道中的通光孔由上至下孔径依次减小。例如，上述第一导光通道中，由上至下的11#通光孔321、21#通光孔341以及31#通光孔351的孔径依次减小。
在本申请实施例中，上述各通光孔可以位于微透镜310下方的任意位置，旨在形成任意四个导光通道，且该四个不同方向的导光通道与显示屏的夹角可以完全相同，也可以不完全相同。换言之，微透镜310对应的第一像素单元331、第二像素单元332、第三像素单元333以及第四像素单元334也可以位于微透镜310下方的任意位置，旨在接收经过四个不同方向的导光通道的四个不同方向的目标指纹光信号。
进一步地，如图7和图8所示，该4个像素单元中均对应设置有第一感光区域3311，第二感光区域3321，第三感光区域3331以及第四感光区域3341。
在一种可能的实施方式中，该4个像素单元中的感光区域只占据像素单元中的小部分区域，以满足接收光信号的要求。
在该申请实施例方式中，第一感光区域3311的中心可以位于第一导光通道的底部，例如，第一感光区域3311的中心可以位于第一导光通道中多个通光孔的连线上。同样的，其它像素单元中的感光区域的中心同样可以位于其对应的导光通道的底部。
通过上述设置，第一目标指纹光信号通过第一导光通道在第一像素单元331上形成第一光斑，为了最大化的接收第一目标指纹光信号，第一像素单元331中的第一感光区域3311可以完全覆盖上述第一光斑。类似地，其它像素单元中的感光区域同样可以完全覆盖其中目标指纹光信号形成的光斑。
可选地，四个像素单元中，若第一像素单元331可以为四边形区域，其长和宽分别为L和W，其中，W≤L，W和L均为正数，第一像素单元331中的第一感光区域3311的长和宽均大于等于0.1×W。当然，四个像素单元中其它三个像素单元和感光区域的尺寸也可以对应满足上述条件。
在此情况下，像素单元中的感光区域较小，但充分接收了经过导光通道后的指纹光信号，满足指纹成像要求，且与此同时，像素单元中的其它区域面积较大，给像素单元的布线提供了足够的空间，降低了工艺要求，提高了工艺制造的效率，且其它区域可以用于设置其它的电路结构，能够提高像素单元的信号处理能力。
如图7和图8所示，在本申请实施例中，4个像素单元所在区域的中心与微透镜的中心在垂直方向上重合，4个像素单元中的4个感光区域偏移于四个像素单元的中心设置。
可选地，4个感光区域除了偏移于像素单元的中心设置外，还向远离于微透镜中心的方向偏移，则能够增大4个感光区域接收的目标指纹光信号角度，从而进一步减小指纹识别单元的厚度。在图5所示的指纹识别单元中，4个感光区域分别位于4个像素单元所在区域的四角。
应理解，在本申请实施例中，4个感光区域也可以分别位于4个像素单元的中心，为了满足感光区域接收光信号的角度需求，可以将四个像素单元 向远离于微透镜中心的方向偏移(4个像素单元所在区域的中心与微透镜的中心在垂直方向上不重合)，增大四个感光区域接收的目标指纹光信号角度，减小指纹识别单元的厚度。
在上述申请实施例中，4个像素单元中的感光区域仅占据像素单元中的小部分区域，在另一种可能的实施方式中，4个像素单元中的感光区域占据像素单元中的大部分区域，以提高像素单元的动态范围。
例如，4个像素单元中的感光区域除了覆盖像素单元上光斑外，还覆盖了其它区域。可选地，4个像素单元中的感光区域占据了像素单元的大部分面积。例如，第一像素单元331中的第一感光区域3311占据了第一像素单元331中的95％以上的面积，或者其它像素单元中各自的感光区域占据了95％以上的面积。
在该实施方式下，像素单元的感光区域增大，能够提高像素单元的满阱容量以及像素单元的动态范围(dynamic range)，从而提升像素单元的整体性能，实现指纹识别装置的高动态范围成像(high dynamic range imaging，HDR)。
在本申请实施例中，4个像素单元可以设置于微透镜下方的任意位置，4个像素单元形成四边形区域的像素区域，该像素区域的中心点与微透镜的中心在垂直方向上重合或者不重合。且4个感光区域可以设置于该4个像素单元中的任意位置，旨在接收经过四个通道的目标指纹光信号，本申请实施例对4个像素单元的位置以及4个感光区域在像素单元中的具体位置不做任何限定。
通过本申请实施例的方案，一个微透镜对应多个像素单元，且多个像素单元分别接收经过该微透镜会聚并通过多个导光通道的多个方向的指纹光信号，该多个方向的指纹光信号分别被多个像素单元接收。相对于一个微透镜对应一个像素单元的技术方案(例如图2中的指纹识别装置)，能够增大提高指纹识别装置的进光量，减小曝光时间，增大指纹识别装置的视场。
此外，本申请实施例中，多个像素单元中感光区域接收的指纹光信号的角度(指纹光信号与垂直于显示屏方向的夹角)由该多个感光区域与微透镜的相对位置关系决定，若感光区域偏移微透镜的中心越远，则感光区域接收的指纹光信号的角度越大。因此，通过灵活设置像素单元和/或感光区域的位置，可以使得感光区域可以接收大角度的指纹光信号，进一步改善干手指的 识别问题，并且能够进一步降低指纹识别单元中光路的厚度，从而减小指纹识别装置的厚度、降低工艺成本。
另外，本申请实施例中的光阑层较于传统的黑胶材料的成本较低，且加工精度高，换言之，该光阑层中的通光孔的大小以及位置均可以精确控制，从而能够提高对导光通道的控制精度，提升指纹识别装置的整体性能。
综上，采用本申请实施例的技术方案，在提高指纹识别装置的整体进光量、改善干手指的识别问题、降低光路厚度，综合提升指纹识别装置性能的同时，还能提高指纹识别装置的制造工艺精度并且降低工艺成本，使得本申请实施例中的指纹识别装置在低成本下具有更广泛的应用场景且有利于其所在电子设备的轻薄化发展。
可选地，上述指纹识别单元302接收的多个方向的目标指纹光信号均为相对于显示屏倾斜的光信号，或者多个方向的目标指纹光信号中一个目标指纹光信号为垂直于显示屏倾斜的光信号，其它目标指纹光信号为倾斜于显示屏的光信号。
换言之，在指纹识别单元302中，至少两层光阑层中形成的多个不同方向的导光通道的方向均为相对于显示屏倾斜的方向。或者，多个不同方向的导光通道中一个导光通道的方向为垂直于显示屏的方向，其它导光通道的方向为相对于显示屏倾斜的方向。
可选地，上述多个方向的目标指纹光信号的角度(目标指纹光信号与垂直于显示屏的方向的夹角)可以在10°至45°之间。
应理解，在具体实现中，本领域技术人员可以根据光路设计要求确定导光通道的方向，从而确定至少两层光阑层中通光孔的分布，形成满足光路设计要求的导光通道，通过特定方向的目标指纹光信号被像素单元接收。
通过选择10°至45°之间目标指纹光信号通过导光通道被像素单元接收，能够合理的将指纹识别装置的光路高度控制在30μm以内，也能最大限度的提升微透镜阵列的占空比。
在上述图3至图8中示出的指纹识别装置300和指纹识别单元302中，至少两层光阑层为三层光阑层，可选地，至少两层光阑层还可以为两层光阑层。
图9示出了另一种指纹识别装置的示意性截面图。
如图9所示，在一个指纹识别单元302中，其只包括顶层光阑层370以 及底层光阑层380。
在一些实施例中，顶层光阑层370以及底层光阑层380同样可以均为第一光阑层，例如其非通光孔区域可以均为红外光透过可见光截止滤光层。
在另一些实施例中，顶层光阑层370可以为第二光阑层，例如其非通光孔区域为蓝色滤光层，底层光阑层380为第一光阑层，例如其非通光孔区域为红外光透过可见光截止滤光层。
在上述实施例中，底层光阑层380的非通光孔区域在用于阻挡可见光并形成4个导光通道的同时，还用于吸收从其下方金属层反射的杂散光信号。在像素单元的周期大于一定阈值时，采用本实施例的方案，能够在保证成像质量的前提下，通过减少光阑层的层数，进一步降低指纹识别装置的成本。
可选地，在本申请实施例中，微透镜310的下表面至传感器芯片330上表面之间的光路高度为H，
其中，底层光阑层380至传感器芯片330上表面之间的距离在H/5至2H/3之间，且顶层光阑层370至传感器芯片330上表面之间的距离在H/2至H之间。
可以理解的是，在本实施方式中，底层光阑层位于顶间层光阑层的下方。作为示例，若底层光阑层380距离传感器芯片330上表面之间的距离为2H/3时，为了满足上述设计条件，并将底间层光阑层设置在底层光阑层上方时，顶间层光阑层370距离传感器芯片330上表面之间的距离可以设计在2H/3至H之间。
在另一种实施方式中，底层光阑层380至传感器芯片330上表面之间的距离在H/5至2H/3之间，或者，顶层光阑层370至传感器芯片330上表面之间的距离在H/2至H之间。
还可以理解的是，图9中的指纹识别装置与图3中指纹识别装置的区别仅在于光阑层的数量不同，图9中的顶层光阑层370可以为图3中的顶层光阑层320，图9中的底层光阑层的中间层光阑层340，图9中指纹识别装置的其它结构以及相关技术方案可以参见上文图3至图7中的描述，此处不再赘述。
还可以理解的是，在本申请中，至少两层光阑层还可以为4层或者4层以上的光阑层。可选地，可以在图3的基础上，在顶层光阑层320和中间层光阑层340之间，和/或，在中间层光阑层340和底层光阑层350之间，增加 设置更多的光阑层，以减少杂散光，提高指纹成像的效果。
在上文实施例中，通过在至少两层光阑层中的每一层光阑层中设置通光孔以形成不同方向的多个导光通道，每个导光通道上通光孔的数量与光阑层的层数相等。
可选地，在此基础上，导光通道上还可以形成有更多的通光孔。例如，在像素单元上方的金属线路层中，还设置有对应于多个导光通道的多个通光孔。
请参见图3和图9，在其提供的指纹识别装置300中，传感器芯片330中设置有位于4个像素单元上方的金属线路层335，该金属线路层335中形成有对应于4个像素单元的4个通光孔，该4个通光孔可以均为圆形孔，且该4个通光孔位于上述底层光阑层350中4个通光孔的下方，与上述三层光阑层中的通光孔共同形成上述4个导光通道，金属线路层335中的通光孔不会改变上述通过4个导光通道的4个目标指纹光信号的方向，并进一步的阻挡影响指纹识别效果的杂散光和干扰光。具体地，在金属线路层335中，对应于第一像素单元331的通光孔为41#通光孔3351，对应于第二像素单元332的通光孔为42#通光孔3352，对应于第三像素单元333的通光孔为43#通光孔3353，对应于第四像素单元334的通光孔为44#通光孔3354。
可选地，该金属线路层335中的4个通光孔的中心可以位于至少两层光阑层中通光孔的中心的连线上，或者也可以位于连线周围的预设范围内。例如，11#通光孔321、21#通光孔341以及31#通光孔351形成第一导光通道，对应于第一像素单元331，该11#通光孔321、21#通光孔341以及31#通光孔351的中心位于第一直线上，该金属线路层335中对应于第一像素单元331的41#通光孔3351的中心也位于上述第一直线上，或者41#通光孔3351的中心也可以位于该第一直线周围的预设范围内。
可选地，该金属线路层335中的4个通光孔的直径可以小于至少两层光阑层中底层光阑层中通光孔的直径，例如，若指纹识别单元302包括三层光阑层，该金属线路层335中的4个通光孔直径可以小于第三光阑层350中4个通光孔的直径。又例如，若指纹识别单元302包括两层光阑层，该金属线路层335中的4个通光孔直径可以小于第二光阑层340中4个通光孔的直径。
这样，通过在金属线路层中设置通光孔，将金属线路层复用为一层光阑层，可以进一步提高导光通道的导光效果，以提升指纹识别效果。
请继续参见图3，在本申请实施例中，指纹识别单元302除了以上介绍的微透镜310、三层光阑层(顶层光阑层320、中间层光阑层340、底层光阑层350)、传感器芯片330中的四个像素单元(第一像素单元331、第二像素单元332、第三像素单元333以及第四像素单元334)以及金属线路层335以外，该指纹识别单元302还可以包括：
第一缓冲层311和第二缓冲层351，该第一缓冲层311设置于微透镜310与顶层光阑层320之间，用于连接该微透镜310与该顶层光阑层320。该第二缓冲层351设置于传感器芯片330与底层光阑层350之间，用于连接该传感器芯片330与该底层光阑层350。
可选地，在顶层光阑层320上方生长该第一缓冲层311，该第一缓冲层311除了形成于顶层光阑层320的上表面，还形成于顶层光阑层320中的通光孔中，例如，形成于图3中的11#通光孔321中。
可选地，该传感器芯片330的表面为硅的氧化物和/或硅的氮化物形成的平坦保护层，则第二缓冲层351可以生长于该保护层上方，并在该第二缓冲层351上方继续制造底层光阑层350。
可以理解的是，该第一缓冲层311和第二缓冲层351均为透明介质，其包括但不限于是透明有机聚合物材料，其折射率包括但不限于是1.55左右。
进一步地，在顶层光阑层320和中间层光阑层340之间，还可以形成有第一透明介质层361，且在中间层光阑层340和底层光阑层350之间，还可以形成有第二透明介质层362。
该第一透明介质层361用于连接顶层光阑层320和中间层光阑层340，并控制顶层光阑层320与中间层光阑层340之间的光路高度，以控制导光通道以及目标指纹光信号的角度。
可选地，在生长中间层光阑层340之后，在其表面生长第一透明介质层361，该第一透明介质层361除了形成于中间层光阑层340的上表面，还形成于中间层光阑层340中的通光孔中，例如，形成于图3和图5中的21#通光孔341，22#通光孔342，23#通光孔343以及24#通光孔344。
该第二透明介质层362用于连接中间层光阑层340和底层光阑层350，并控制中间层光阑层340与底层光阑层350之间的光路高度，以进一步调整控制导光通道以及目标指纹光信号的角度。
可选地，在生长底层光阑层350之后，在其表面生长第二透明介质层 362，该第二透明介质层362除了形成于底层光阑层350的上表面，还形成于底层光阑层350中的通光孔中，例如，形成于图3和图5中的31#通光孔351，32#通光孔352，33#通光孔353以及34#通光孔354。
可以理解的是，该第一透明介质层361和第二透明介质层362同样均为透明介质，其包括但不限于是透明有机聚合物材料，其折射率可以与上述第一缓冲层311和第二缓冲层351的折射率相近(折射率之差小于预设阈值)，例如第一透明介质层361和第二透明介质层362的折射率也可以在1.55左右。
类似地，请参见图9，指纹识别单元302除了以上介绍的微透镜310、三层光阑层(顶层光阑层370和底层光阑层380)、传感器芯片330中的四个像素单元以及金属线路层335以外，该指纹识别单元302还可以包括：
第一缓冲层311和第二缓冲层351，该第一缓冲层311设置于微透镜310与顶层光阑层370之间，用于连接该微透镜310与该顶层光阑层370。该第二缓冲层351设置于传感器芯片330与底层光阑层380之间，用于连接该传感器芯片330与该底层光阑层380。
进一步地，在顶层光阑层370和底层光阑层380之间，还可以形成有第一透明介质层361。
具体地，该第一缓冲层311、第二缓冲层351以及第一透明介质层的相关技术方案可以参见上文相关描述，此处不再赘述。
在上述申请实施例中，指纹识别单元302中的每一层结构的设计以及其相关参数，均是经过大量实验验证之后，用于优化指纹图像质量并降低指纹识别装置厚度的。例如，至少两层光阑层的顶层光阑层(例如，顶层光阑层320)，其通光孔(例如，11#通光孔321)的孔径与微透镜周期的比率在预设阈值之间，以平衡进光量与遮挡杂散光。又例如，设计至少两层光阑层除顶层光阑层以外的其它光阑层中通光孔的大小与位置，保证其顺着接收光线的中心平滑过渡至传感器芯片内部，以保证成像质量。另外，设计微透镜的曲率半径，使得指纹能较好的成像于传感器芯片的成像区域，即指纹物方像点在传感器芯片成像的弥散斑直径尽量小。
上文结合图3至图9，说明了本申请中指纹识别装置300的基本结构，进一步地，下文通过介绍指纹识别装置300中像素值的处理方法，可以避免产生指纹图像产生摩尔条纹，在提高指纹图像质量的同时，提高图像处理速 度，以提高用户体验。
在本申请实施例中，仍旧以指纹识别单元302中包括4个像素单元进行举例说明。
可以理解的是，指纹识别装置300中包括多个指纹识别单元302，每个指纹识别单元中包括4个像素单元，则所有的像素单元可以形成指纹识别装置300的像素阵列。
图10示出了一种指纹识别装置300中的像素阵列303的示意图。如图10所示，数字“1”表示上述第一像素单元331，数字“2”表示上述第二像素单元332，数字“3”表示上述第三像素单元333，数字“4”表示上述第四像素单元334。
如图10所示，多个第一像素单元331之间、多个第二像素单元332之间、多个第三像素单元333之间、以及多个第四像素单元334之间彼此均不相邻。
应理解，上述图10仅为一种像素阵列303的示意性排列图，在一个指纹识别单元中，其中第一像素单元331、第二像素单元332、第三像素单元333和第四像素单元334的相对位置关系可以变换，例如，图中的第一像素单元331的位置也可为第二像素单元332或者第三像素单元333或者第四像素单元334，本申请实施例对此不做限定。
在该像素阵列303中，多个第一像素单元331接收一个方向的目标指纹光信号，该目标指纹光信号用于形成手指的第一指纹图像。多个第二像素单元332接收另一个方向的指纹光信号，该指纹光信号用于形成手指的第二指纹图像。多个第三像素单元333接收第三个方向的指纹光信号，该指纹光信号用于形成手指的第三指纹图像。多个第四像素单元334接收第四个方向的指纹光信号，该指纹光信号用于形成手指的第四指纹图像。该第一指纹图像、第二指纹图像、第三指纹图像以及第四指纹图像可以单独用于指纹识别，也可以将其中的任意两张或者三张指纹图像进行重构，将重构后的指纹图像进行指纹识别。
可选地，在像素阵列303中，每个像素单元均接收其对应方向的目标指纹光信号，产生一个原始像素值，图10所示的像素阵列303的示意图也可以看成是原始像素值形成的原始图像示意图。
该像素阵列303形成的原始像素值需要经过物理像素合成和/或数字像 素合成(binning)等处理，最终形成用于进行指纹识别的上述第一指纹图像、第二指纹图像、第三指纹图像以及第四指纹图像。
图11示出了一种图像处理方法的示意图。
如图11所示，1#图即为图10中像素阵列303形成的原始图像示意图。
在1#图中，数字“1”表示上述第一像素单元331产生的原始像素值，数字“2”表示上述第二像素单元332产生的原始像素值，数字“3”表示上述第三像素单元333产生的原始像素值，数字“4”表示上述第四像素单元334产生的原始像素值。
可选地，在本申请实施例中，指纹识别装置300包括第一求和平均电路、第二求和平均电路、第三求和平均电路以及第四求和平均电路，用于对原始像素值进行物理像素合成。
具体地，第一求和平均电路用于通过金属走线连接至像素阵列302中的多个第一像素单元331，并将每X1×X2个第一像素单元331的原始像素值进行求和平均，形成第一中间指纹图像中的一个像素值。
类似地，第二求和平均电路用于通过金属走线连接至像素阵列302中的多个第二像素单元332，并将每X1×X2个第二像素单元332的原始像素值进行求和平均，形成第二中间指纹图像中的一个像素值。
第三求和平均电路用于通过金属走线连接至像素阵列302中的多个第三像素单元333，并将每X1×X2个第三像素单元333的原始像素值进行求和平均，形成第三中间指纹图像中的一个像素值。
第四求和平均电路用于通过金属走线连接至像素阵列302中的多个第四像素单元334，并将每X1×X2个第四像素单元334的原始像素值进行求和平均，形成第四中间指纹图像中的一个像素值。
可选地，该X1×X2个第一像素单元331可以为像素阵列302的多个第一像素单元331中相邻的X1×X2个像素单元，例如，可以为2×2的4个第一像素单元，或者为3×3的9个第一像素单元，同样的，该X1×X2个第二像素单元332可以为像素阵列302的多个第二像素单元332中相邻的X个像素单元，该X1×X2个第三像素单元333可以为像素阵列302的多个第三像素单元333中相邻的X1×X2个像素单元，或者该X1×X2个第四像素单元334可以为像素阵列302的多个第四像素单元334中相邻的X1×X2个像素单元，本申请实施例对X1和X2不做具体限定。
在一些实施方式中，
Figure PCTCN2020106915-appb-000001
则上述第一中间指纹图像、第二中间指纹图像、第三中间指纹图像以及第四中间指纹图像可以参见图11中的2#号图。
其中，第一中间指纹图像中的像素值(图11中表示为“1'”)为第一像素单元331的2×2个原始像素值(图11中表示为“1”)经过求和平均后得到的，类似地，第二中间指纹图像中的像素值(图11中表示为“2'”)为第一像素单元332的2×2个原始像素值(图11中表示为“2”)经过求和平均后得到的，第三中间指纹图像中的像素值(图11中表示为“3'”)为第一像素单元333的2×2个原始像素值(图11中表示为“3”)经过求和平均后得到的，第四中间指纹图像中的像素值(图11中表示为“4'”)为第一像素单元334的2×2个原始像素值(图11中表示为“4”)经过求和平均后得到的。
经过上述物理像素合成后，形成了4张中间指纹图像，且4张中间指纹图像的像素值数量的总和为原始图像中原始像素值数量的1/4，每张中间指纹图像的像素值数量为原始图像中原始像素值数量的1/16。
通过物理像素合成后，像素值数量大大减少，有利于后续数字图像的处理，提高图像处理效率。
可选地，经过上述物理像素合成之后，进一步地，还可以对上述4张中间指纹图像进行数字像素合成，以进一步减小像素值的数量，提高图像处理效率。
可选地，数字像素合成的过程不通过模拟硬件电路实现，而可以通过数字电路实现，例如，指纹识别装置中可以包括处理单元，用于第一中间指纹图像、第二中间指纹图像、第三中间指纹图像以及第四中间指纹图像进行数字像素合成，该处理单元包括但不限于是图像信号处理器(image signal processor，ISP)。
在一些实施方式中，上述第一中间指纹图像中每Y1×Y2个像素值用于进行数字像素合成，形成第一指纹图像中的一个像素值；第二中间指纹图像中每Y1×Y2个像素值用于进行数字像素合成，形成第二指纹图像中的一个像素值；第三中间指纹图像中每Y1×Y2个像素值用于进行数字像素合成，形成第三指纹图像中的一个像素值；第四中间指纹图像中每Y1×Y2个像素值用于进行数字像素合成，形成第四指纹图像中的一个像素值；其中，Y1和Y2为正整数。
可选地，
Figure PCTCN2020106915-appb-000002
则上述第一指纹图像、第二指纹图像、第三指纹图像以及第四指纹图像可以参见图11中的3#号图。
其中，第一指纹图像中的像素值(图11中表示为“1””)为第一中间指纹图像中的2×2个像素值(图11中表示为“1'”)经过求和平均后得到的，类似地，第二指纹图像中的像素值(图11中表示为“2””)为第二中间指纹图像中的2×2个像素值(图11中表示为“2'”)经过求和平均后得到的，第三指纹图像中的像素值(图11中表示为“3””)为第三中间指纹图像中的2×2个像素值(图11中表示为“3'”)经过求和平均后得到的，第四指纹图像中的像素值(图11中表示为“4””)为第四中间指纹图像中的2×2个像素值(图11中表示为“4'”)经过求和平均后得到的。
经过上述数字像素合成后，形成了4张用于指纹识别的指纹图像，该每张指纹图像的像素值数量为原始图像中原始像素值数量的1/64。
可以理解的是，该4张指纹图像还可以经过其它后续的图像处理之后，例如，将4张指纹图像进行穿插重构为一张指纹图像后再用于进行指纹识别，或者，4张指纹图像中任意一张指纹图像可以单独用于指纹识别。本申请实施例中仅列举了图像处理过程中的像素合成过程，其它图像处理包括但不限于现有技术中的图像处理过程，此处不做叙述。
还可以理解的是，上文中物理像素合成以及数字像素合成的过程，均将多个像素值的平均值作为合成后的像素值，除了该方式外，还可以将多个像素值的最大值、最小值或者根据其它计算方式得到的计算值作为合成后的像素值，本申请实施例对此不做具体限定。
另外，如图11所示，在对4张中间指纹图像进行数字像素合成之前，可以对该4张中间指纹图像进行低通滤波，以削弱莫尔条纹的影响，对该4张中间指纹图像进行低通滤波之后，再执行上述数字像素合成处理，在减少像素数据量的同时，能够进一步优化指纹图像质量。
可选地，在本申请实施例中，指纹识别装置300还可以包括低通滤波器(low-pass filter，LPF)，用于执行上述低通滤波处理。
如上述图11中的1#图所示，在原始图像中，在X方向与Y方向上，相邻两个接收相同方向光信号的像素单元的像素值之间的距离为L，换句话说，指纹识别装置300的空间采样周期为L。
具体地，上述指纹识别装置300的空间采样周期L，也可以理解为多个 指纹识别单元的排列周期，或者多个指纹识别单元形成的微透镜阵列中微透镜的排列周期，或者多个指纹单元形成的像素阵列中像素单元组的排列周期。
通过X1×X2的物理像素合成之后，若X1＝X2＝X，则指纹识别装置300的空间采样周期由L变为X×L。再经过Y1×Y2的数字像素合成之后，Y1＝Y2＝Y，则指纹识别装置300的空间采样周期由X×L变为Y×X×L。
在一些实施方式中，L为12μm至20μm之间，例如L＝15μm，X1＝X2＝2，X1＝X2＝2，则指纹识别装置300的空间采样周期为60μm，其处于40μm至70μm的空间采样周期之间，为较优的指纹空间采样周期。
除了上述将原始图像中的原始像素值进行物理像素合成、低通滤波以及数字像素合成后，形成指纹图像以外，在另一种实施方式中，也可以仅将原始图像中的原始像素值进行物理像素合成或者数字像素合成，例如，仅将原始图像中的原始像素值进行3×3的物理像素合成，若指纹识别装置原始的空间采样周期L＝15μm，则经过3×3的物理像素合成之后，指纹识别装置的空间采样周期为45μm，后续不再进行低通滤波以及数字像素合成，采用该实施方式，指纹识别装置的空间采样周期也处于40μm至70μm的空间采样周期之间，也能够得到较好的指纹图像。
可选地，在本申请实施方式中，上述指纹识别装置的空间采样周期与显示屏的空间成像周期相关，例如，指纹识别装置300的空间采样周期小于显示屏的空间成像周期的一半，可以使得指纹识别装置的空间采样周期相对显示屏的空间成像周期满足奈奎斯特采样定律，即，能够避免指纹图像中出现莫尔条纹，相应的，提升指纹识别效果。
其中，显示屏的空间成像周期可以为显示屏的像素单元的周期。或者，显示屏的空间成像周期还可以为显示屏的像素单元周期与光学成像系统缩放系数K的比值，K为指纹识别装置中像素单元中的感光区域内显示的图像与该像素单元在该感光区域内采集的图像之间的缩放比例。
目前市面现有高像素密度屏的像素单元周期，即上述显示屏的空间成像周期绝大多数在45um以上，对于密集像素排列的屏，其屏结构周期的更复杂。通常指纹模组由安装公差，要求例如±2.5°的安装公差内，使得莫尔条纹的周期处于指纹周期外。若指纹识别装置的空间采样周期为25-50um之间，则对于密集像素排列的屏可能没有合适的公差角度或者需要旋转较大的 角度才能将莫尔条纹的周期远离指纹周期。由于不同屏幕的参数可能不同，因此，对于不同的屏幕，指纹识别装置的旋转角度会有差异，这就无法做到产品的归一化。
为了解决这一问题，通过本申请实施例的方案，若使得指纹识别装置的空间采样率周期小于显示屏的空间成像周期的一半，例如小于20um，则可以能够避免指纹图像中出现莫尔条纹，相应的，提升指纹识别效果。与此同时，还可以增加指纹模组的通用性，不用旋转就可以解决市面上几乎所有屏幕造成的指纹图像中出现莫尔条纹问题。
通过上述说明可知，本申请实施例中指纹识别装置的空间采样率不仅仅取决于指纹识别装置原始的空间采样率，即不仅仅取决于接收相同方向的像素单元的排列周期，还取决于后续的像素合成处理过程。综合考虑后续的图像处理过程以及指纹识别装置本身的空间采样周期，采取最优的实施方案，在解决指纹图像中的莫尔条纹问题，提高指纹图像质量的同时，提高图像处理速度。
本申请实施例还提供了一种电子设备，该电子设备可以包括显示屏以及上述本申请实施例的指纹识别装置，其中，该指纹识别装置设置于显示屏下方，以实现屏下光学指纹识别。该电子设备可以为任何具有显示屏的电子设备。
其中，显示屏可以采用以上描述中的显示屏，例如OLED显示屏或其他显示屏，显示屏的相关说明可以参考以上描述中关于显示屏的描述，为了简洁，在此不再赘述。
在本申请的一些实施例中，该显示屏的下方可以设置有一层泡棉层，该泡棉层在指纹识别装置的上方可以设置有至少一个开孔，该至少一个开孔用于将经由手指反射的光信号传输至指纹识别装置。
例如，显示屏下方有一层黑色泡棉，该黑色泡棉在指纹识别装置的上方可以设置有一个开孔，当手指放于点亮的显示屏上方时，手指就会反射显示屏发出的光，经由手指反射的反射光会穿透显示屏以及通过至少一个开孔传输至指纹识别装置。指纹是一个漫反射体，其反射光在各方向都存在。
可选地，手指放置区域处，或者说指纹检测区域处，显示屏显示绿色、青色或者白色光斑，指纹识别装置利用该绿色、青色或者白色光源进行指纹识别。
此时，可以使用指纹识别装置中的特定光路，使指纹识别装置中的光学感应像素阵列接收多个方向的倾斜光信号，该指纹识别装置中的处理单元或与该指纹识别装置相连的处理单元通过算法可以获取重构的指纹图像，进而进行指纹识别。
在本申请的一些实施例中，指纹识别装置和显示屏之间可以存在或不存在间隙。
例如，指纹识别装置和显示屏之间可以存在0至1mm的间隙。
在本申请的一些实施例中，指纹识别装置可以将采集的图像输出给计算机专用处理器或者电子设备的专用处理器，进而进行指纹识别。
应理解，本申请实施例的处理器可以是一种集成电路芯片，具有信号的处理能力。在实现过程中，上述方法实施例的各步骤可以通过处理器中的硬件的集成逻辑电路或者软件形式的指令完成。上述的处理器可以是通用处理器、数字信号处理器(Digital Signal Processor，DSP)、专用集成电路(Application Specific Integrated Circuit，ASIC)、现成可编程门阵列(Field Programmable Gate Array，FPGA)或者其他可编程逻辑器件、分立门或者晶体管逻辑器件、分立硬件组件。可以实现或者执行本申请实施例中的公开的各方法、步骤及逻辑框图。通用处理器可以是微处理器或者该处理器也可以是任何常规的处理器等。结合本申请实施例所公开的方法的步骤可以直接体现为硬件译码处理器执行完成，或者用译码处理器中的硬件及软件模块组合执行完成。软件模块可以位于随机存储器，闪存、只读存储器，可编程只读存储器或者电可擦写可编程存储器、寄存器等本领域成熟的存储介质中。该存储介质位于存储器，处理器读取存储器中的信息，结合其硬件完成上述方法的步骤。
可以理解，本申请实施例的指纹识别还可以包括存储器，存储器可以是易失性存储器或非易失性存储器，或可包括易失性和非易失性存储器两者。其中，非易失性存储器可以是只读存储器(Read-Only Memory，ROM)、可编程只读存储器(Programmable ROM，PROM)、可擦除可编程只读存储器(Erasable PROM，EPROM)、电可擦除可编程只读存储器(Electrically EPROM，EEPROM)或闪存。易失性存储器可以是随机存取存储器(Random Access Memory，RAM)，其用作外部高速缓存。通过示例性但不是限制性说明，许多形式的RAM可用，例如静态随机存取存储器(Static RAM， SRAM)、动态随机存取存储器(Dynamic RAM，DRAM)、同步动态随机存取存储器(Synchronous DRAM，SDRAM)、双倍数据速率同步动态随机存取存储器(Double Data Rate SDRAM，DDR SDRAM)、增强型同步动态随机存取存储器(Enhanced SDRAM，ESDRAM)、同步连接动态随机存取存储器(Synchlink DRAM，SLDRAM)和直接内存总线随机存取存储器(Direct Rambus RAM，DR RAM)。应注意，本文描述的系统和方法的存储器旨在包括但不限于这些和任意其它适合类型的存储器。
本领域普通技术人员可以意识到，结合本文中所公开的实施例描述的各示例的单元及算法步骤，能够以电子硬件、或者计算机软件和电子硬件的结合来实现。这些功能究竟以硬件还是软件方式来执行，取决于技术方案的特定应用和设计约束条件。专业技术人员可以对每个特定的应用来使用不同方法来实现所描述的功能，但是这种实现不应认为超出本申请的范围。
所属领域的技术人员可以清楚地了解到，为描述的方便和简洁，上述描述的系统、装置和单元的具体工作过程，可以参考前述方法实施例中的对应过程，在此不再赘述。
在本申请所提供的几个实施例中，应所述理解到，所揭露的系统、装置和方法，可以通过其它的方式实现。例如，以上所描述的装置实施例仅仅是示意性的，例如，所述单元的划分，仅仅为一种逻辑功能划分，实际实现时可以有另外的划分方式，例如多个单元或组件可以结合或者可以集成到另一个系统，或一些特征可以忽略，或不执行。另一点，所显示或讨论的相互之间的耦合或直接耦合或通信连接可以是通过一些接口，装置或单元的间接耦合或通信连接，可以是电性，机械或其它的形式。
所述作为分离部件说明的单元可以是或者也可以不是物理上分开的，作为单元显示的部件可以是或者也可以不是物理单元，即可以位于一个地方，或者也可以分布到多个网络单元上。可以根据实际的需要选择其中的部分或者全部单元来实现本实施例方案的目的。
另外，在本申请各个实施例中的各功能单元可以集成在一个处理单元中，也可以是各个单元单独物理存在，也可以两个或两个以上单元集成在一个单元中。
所述功能如果以软件功能单元的形式实现并作为独立的产品销售或使用时，可以存储在一个计算机可读取存储介质中。基于这样的理解，本申请 的技术方案本质上或者说对现有技术做出贡献的部分或者所述技术方案的部分可以以软件产品的形式体现出来，所述计算机软件产品存储在一个存储介质中，包括若干指令用以使得一台计算机设备(可以是个人计算机，服务器，或者网络设备等)执行本申请各个实施例所述方法的全部或部分步骤。而前述的存储介质包括：U盘、移动硬盘、只读存储器(Read-Only Memory，ROM)、随机存取存储器(Random Access Memory，RAM)、磁碟或者光盘等各种可以存储程序代码的介质。
以上所述，仅为本申请的具体实施方式，但本申请的保护范围并不局限于此，任何熟悉本技术领域的技术人员在本申请揭露的技术范围内，可轻易想到变化或替换，都应涵盖在本申请的保护范围之内。因此，本申请的保护范围应以权利要求的保护范围为准。

Claims (51)

  1. 一种指纹识别装置，其特征在于，适用于显示屏的下方以实现屏下光学指纹识别，所述指纹识别装置包括：
    指纹识别模组，包括多个指纹识别单元，所述多个指纹识别单元中的每个指纹识别单元包括：
    微透镜；
    至少两层光阑层，设置在所述微透镜下方，所述至少两层光阑层中的每一层光阑层中设置通光孔以形成不同方向的多个导光通道，在所述至少两层光阑层中，至少一层第一光阑层的非通光孔区域用于吸收可见光，至少一层第二光阑层的非通光孔区域用于透过非像素敏感光并吸收像素敏感光；
    多个像素单元，设置在所述至少两层光阑层下方，所述多个像素单元一一对应的分别位于所述多个导光通道的底部，且所述多个像素单元对所述非像素敏感光的响应度小于等于第一预设阈值，对所述像素敏感光的响应度大于等于第二预设阈值，所述第一预设阈值小于所述第二预设阈值；
    其中，从所述显示屏上方的手指反射或散射后返回的指纹光信号通过所述微透镜会聚后，其中不同方向的多个目标指纹光信号分别经过所述多个导光通道传输至所述多个像素单元，所述多个目标指纹光信号用于检测所述手指的指纹信息。
  2. 根据权利要求1所述的指纹识别装置，其特征在于，所述第一光阑层的非通光孔区域还用于透过红外光，所述第一光阑层的非通光孔区域为红外光透过可见光截止滤光层。
  3. 根据权利要求2所述的指纹识别装置，其特征在于，所述指纹识别装置还包括：
    红外截止滤光片，设置于所述显示屏至所述指纹识别模组中的所述多个像素单元之间的光路中。
  4. 根据权利要求3所述的指纹识别装置，其特征在于，所述红外截止滤光片设置于所述指纹识别模组上方。
  5. 根据权利要求1至3中任一项所述的指纹识别装置，其特征在于，所述非像素敏感光为第一颜色光，所述像素敏感光包括第二颜色光，所述第二光阑层中的非通光孔区域用于透过所述第一颜色光并吸收所述第二颜色光。
  6. 根据权利要求5所述的指纹识别装置，其特征在于，所述第一颜色光为蓝光，所述第二光阑层的非通光孔区域为蓝色滤光材料形成的滤光层或者为紫色滤光材料形成的滤光层。
  7. 根据权利要求5所述的指纹识别装置，其特征在于，所述显示屏用于在所述手指按压区域发出所述第二颜色光，所述第二颜色光从所述手指反射或散射后返回的第二颜色指纹光通过所述微透镜会聚后，其中不同方向的多个第二颜色目标指纹光信号分别经过所述多个导光通道传输至所述多个像素单元，所述多个第二颜色目标指纹光信号用于检测所述手指的指纹信息。
  8. 根据权利要求7所述的指纹识别装置，其特征在于，所述第二颜色光为绿光或者青光。
  9. 根据权利要求1至8中任一项所述的指纹识别装置，其特征在于，所述第一预设阈值小于等于10％，所述第二预设阈值大于等于70％。
  10. 根据权利要求1至9中任一项所述的指纹识别装置，其特征在于，所述至少一层第二光阑层的非通光孔区域对所述像素敏感光的吸收率大于第三预设阈值。
  11. 根据权利要求10所述的指纹识别装置，其特征在于，所述第三预设阈值大于等于70％。
  12. 根据权利要求1至11中任一项所述的指纹识别装置，其特征在于，所述至少两层光阑层为三层光阑层，所述三层光阑层中的中间层光阑层为所述第一光阑层，所述三层光阑层中的顶层光阑层和底层光阑层为所述第二光阑层。
  13. 根据权利要求12所述的指纹识别装置，其特征在于，所述三层光阑层中的中间层光阑层中设置有与所述多个像素单元分别一一对应的多个通光孔，以形成所述多个导光通道。
  14. 根据权利要求13所述的指纹识别装置，其特征在于，所述三层光阑层中的顶层光阑层中设置有一个通光孔，且所述三层光阑层中的底层光阑层中设置有与所述多个像素单元分别一一对应的多个通光孔，以形成所述多个导光通道。
  15. 根据权利要求12至14中任一项所述的指纹识别装置，其特征在于，所述多个像素单元形成于传感器芯片中，所述微透镜的下表面至所述传感器 芯片上表面之间的光路高度为H，
    所述三层光阑层中的底层光阑层至所述传感器芯片上表面之间的距离在0至H/3之间，所述三层光阑层中的中间层光阑层至所述传感器芯片上表面之间的距离在H/5至2H/3之间，所述至少两层光阑层中的顶层光阑层至所述传感器芯片上表面之间的距离在H/2至H之间。
  16. 根据权利要求1至11中任一项所述的指纹识别装置，其特征在于，所述至少两层光阑层为两层光阑层，所述两层光阑层中的底层光阑层为所述第一光阑层，所述两层光阑层中的顶层光阑层为所述第二光阑层。
  17. 根据权利要求16所述的指纹识别装置，其特征在于，所述两层光阑层中的底层光阑层中设置有与所述多个像素单元分别一一对应的多个通光孔，以形成所述多个导光通道。
  18. 根据权利要求17所述的指纹识别装置，其特征在于，所述两层光阑层中的顶层光阑层中设置有一个通光孔，以形成所述多个导光通道。
  19. 根据权利要求16至18中任一项所述的指纹识别装置，其特征在于，所述多个像素单元形成于传感器芯片中，所述微透镜的下表面至所述传感器芯片上表面之间的光路高度为H，
    所述至少两层光阑层中的底层光阑层至所述传感器芯片上表面之间的距离在H/5至2H/3之间，所述至少两层光阑层中的顶层光阑层至所述传感器芯片上表面之间的距离在H/2至H之间。
  20. 根据权利要求1至19中任一项所述的指纹识别装置，其特征在于，所述多个导光通道中的通光孔由上至下孔径依次减小。
  21. 根据权利要求20所述的指纹识别装置，其特征在于，所述多个像素单元形成于传感器芯片中，所述微透镜的直径为D，所述微透镜的下表面至所述传感器芯片上表面之间的光路高度为H，所述至少两层光阑层中的一层光阑层与所述传感器芯片上表面之间的光路高度为h，所述一层光阑层中通光孔的孔径d处于(1±0.3)×D×h/H的范围之间。
  22. 根据权利要求1至21中任一项所述的指纹识别装置，其特征在于，所述指纹识别装置还包括：
    金属线路层，所述金属线路层中设置有多个通光孔，所述多个通光孔一一对应的设置于所述多个像素单元上方，并一一对应的设置于所述多个导光通道下方；
    所述多个目标指纹光信号通过所述多个导光通道传导至所述金属线路层中的所述多个通光孔，并通过所述多个通光孔传导至所述多个像素单元。
  23. 根据权利要求22所述的指纹识别装置，其特征在于，所述多个导光通道中第一导光通道中的通光孔的中心位于第一直线上，所述第一导光通道对应的所述金属线路层中的通光孔也位于所述第一直线上。
  24. 根据权利要求22所述的指纹识别装置，其特征在于，所述至少两层光阑层中的通光孔以及所述金属线路层中的通光孔均为圆形通光孔。
  25. 根据权利要求24所述的指纹识别装置，其特征在于，所述金属线路层中的通光孔的直径小于所述至少两层光阑层中底层光阑层中的通光孔的直径。
  26. 根据权利要求1至25中任一项所述的指纹识别装置，其特征在于，所述每个指纹识别单元还包括：
    透明介质层，用于连接所述至少两层光阑层。
  27. 根据权利要求26所述的指纹识别装置，其特征在于，所述每个指纹识别单元还包括：
    第一缓冲层，用于连接所述微透镜与所述至少两层光阑层中的顶层光阑层；
    第二缓冲层，用于连接所述传感器芯片与所述至少两层光阑层中的底层光阑层。
  28. 根据权利要求27所述的指纹识别装置，其特征在于，所述透明介质层与所述第一缓冲层的折射率之差，以及所述透明介质层与所述第二缓冲层的折射率之差均在预设阈值之内。
  29. 根据权利要求1至28中任一项所述的指纹识别装置，其特征在于，所述多个像素单元为四个像素单元，所述四个像素单元形成四边形区域的像素区域，所述像素区域的中心点与所述微透镜的中心在垂直方向上重合或者不重合。
  30. 根据权利要求29所述的指纹识别装置，其特征在于，所述多个导光通道为四个导光通道，所述四个导光通道的方向中至少三个导光通道的方向相对于所述显示屏倾斜。
  31. 根据权利要求30所述的指纹识别装置，其特征在于，所述四个导光通道与垂直于所述显示屏方向的夹角在10至45°之间。
  32. 根据权利要求29至31中任一项所述的指纹识别装置，其特征在于，所述四个像素单元中分别包括四个感光区域，所述四个感光区域分别位于所述四个导光通道的底部。
  33. 根据权利要求32所述的指纹识别装置，其特征在于，所述四个感光区域中的至少一个感光区域偏离于其所在的像素单元的中心设置。
  34. 根据权利要求33所述的指纹识别装置，其特征在于，所述至少一个感光区域向远离于所述微透镜中心的方向偏离。
  35. 根据权利要求34所述的指纹识别装置，其特征在于，所述四个像素单元形成四边形的像素区域，所述四个感光区域分别位于所述像素区域的四角。
  36. 根据权利要求29至35中任一项所述的指纹识别装置，其特征在于，所述指纹识别模组包括多组所述四个像素单元；
    多组所述四个像素单元中的多个第一像素单元接收的光信号用于形成所述手指的第一指纹图像，多组所述四个像素单元中的多个第二像素单元接收的光信号用于形成所述手指的第二指纹图像，多组所述四个像素单元中的多个第三像素单元接收的光信号用于形成所述手指的第三指纹图像，多组所述四个像素单元中的多个第四像素单元接收的光信号用于形成所述手指的第四指纹图像，所述第一指纹图像、所述第二指纹图像、所述第三指纹图像和所述第四指纹图像中的一张或者多张图像用于进行指纹识别。
  37. 根据权利要求36所述的指纹识别装置，其特征在于，所述多个第一像素单元中每X1×X2个第一像素单元连接至第一求和平均电路进行物理像素合成，形成第一中间指纹图像中的一个像素值；
    所述多个第二像素单元中每X1×X2个第二像素单元连接至第二求和平均电路进行物理像素合成，形成第二中间指纹图像中的一个像素值；
    所述多个第三像素单元中每X1×X2个第三像素单元连接至第三求和平均电路进行物理像素合成，形成第三中间指纹图像中的一个像素值；
    所述多个第四像素单元中每X1×X2个第四像素单元连接至第四求和平均电路进行物理像素合成，形成第四中间指纹图像中的一个像素值；其中，X1和X2为正整数。
  38. 根据权利要求37所述的指纹识别装置，其特征在于，所述指纹识别装置还包括：
    所述第一求和平均电路，所述第二求和平均电路，所述第三求和平均电路以及所述第四求和平均电路。
  39. 根据权利要求37所述的指纹识别装置，其特征在于，所述第一中间指纹图像中每Y1×Y2个像素值用于进行数字像素合成，形成所述第一指纹图像中的一个像素值；
    所述第二中间指纹图像中每Y1×Y2个像素值用于进行数字像素合成，形成所述第二指纹图像中的一个像素值；
    所述第三中间指纹图像中每Y1×Y2个像素值用于进行数字像素合成，形成所述第三指纹图像中的一个像素值；
    所述第四中间指纹图像中每Y1×Y2个像素值用于进行数字像素合成，形成所述第四指纹图像中的一个像素值；其中，Y1和Y2为正整数。
  40. 根据权利要求39所述的指纹识别装置，其特征在于，所述指纹识别装置还包括：
    处理单元，用于对所述第一中间指纹图像、所述第二中间指纹图像、所述第三中间指纹图像以及所述第四中间指纹图像进行数字像素合成。
  41. 根据权利要求39所述的指纹识别装置，其特征在于，所述第一中间指纹图像、所述第二中间指纹图像、所述第三中间指纹图像以及所述第四中间指纹图像用于经过低通滤波处理后进行数字像素合成。
  42. 根据权利要求41所述的指纹识别装置，其特征在于，所述指纹识别装置还包括：
    低通滤波器，用于对所述第一中间指纹图像、所述第二中间指纹图像、所述第三中间指纹图像以及所述第四中间指纹图像进行低通滤波处理。
  43. 根据权利要求39所述的指纹识别装置，其特征在于，X1＝X2＝Y1＝Y2＝2。
  44. 根据权利要求36至42中任一项所述的指纹识别装置，其特征在于，所述多个第一像素单元之间互不相邻，所述多个第二像素单元之间互不相邻，所述多个第三像素单元之间互不相邻，且所述多个第四像素单元之间互不相邻。
  45. 根据权利要求1至44中任一项所述的指纹识别装置，其特征在于，所述显示屏中发光像素的排列周期为P1，所述指纹识别装置的空间采样周期P2＜P1/2。
  46. 根据权利要求45所述的指纹识别装置，其特征在于，所述指纹识别装置的空间采样周期根据所述多个指纹识别单元的排列周期以及像素合成方式计算得到。
  47. 根据权利要求1至46中任一项所述的指纹识别装置，其特征在于，所述多个指纹识别单元的排列周期在12μm至20μm之间。
  48. 根据权利要求1至47中任一项所述的指纹识别装置，其特征在于，所述多个指纹识别单元中每个指纹识别单元的光路厚度在30μm以内。
  49. 根据权利要求1至48中任一项所述的指纹识别装置，其特征在于，所述指纹识别装置和所述显示屏之间的距离为0至1mm。
  50. 一种电子设备，其特征在于，包括：显示屏；以及
    根据权利要求1至49中任一项所述的指纹识别装置，所述指纹识别装置设置于所述显示屏下方，以实现屏下光学指纹识别。
  51. 根据权利要求50所述的电子设备，其特征在于，所述显示屏用于在指纹检测区域显示绿色、青色或者白色光斑，所述指纹识别装置用于接收绿色、青色或者白色目标指纹光信号，以检测手指的指纹信息。
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