WO2022205476A1 - 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
WO2022205476A1
WO2022205476A1 PCT/CN2021/085455 CN2021085455W WO2022205476A1 WO 2022205476 A1 WO2022205476 A1 WO 2022205476A1 CN 2021085455 W CN2021085455 W CN 2021085455W WO 2022205476 A1 WO2022205476 A1 WO 2022205476A1
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WIPO (PCT)
Prior art keywords
light
fingerprint identification
blocking layer
layer
identification device
Prior art date
Application number
PCT/CN2021/085455
Other languages
English (en)
French (fr)
Inventor
蔡斐欣
王胤
张思超
林峻贤
Original Assignee
迪克创新科技有限公司
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Application filed by 迪克创新科技有限公司 filed Critical 迪克创新科技有限公司
Priority to PCT/CN2021/085455 priority Critical patent/WO2022205476A1/zh
Priority to EP21912303.1A priority patent/EP4089576B1/en
Priority to KR1020227022470A priority patent/KR20220137881A/ko
Publication of WO2022205476A1 publication Critical patent/WO2022205476A1/zh

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    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B3/00—Simple or compound lenses
    • G02B3/0006—Arrays
    • G02B3/0037—Arrays characterized by the distribution or form of lenses
    • G02B3/0056—Arrays characterized by the distribution or form of lenses arranged along two different directions in a plane, e.g. honeycomb arrangement of lenses
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B27/00—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00
    • G02B27/30—Collimators
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B3/00—Simple or compound lenses
    • G02B3/0006—Arrays
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B5/00—Optical elements other than lenses
    • G02B5/003—Light absorbing elements
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06V—IMAGE OR VIDEO RECOGNITION OR UNDERSTANDING
    • G06V40/00—Recognition of biometric, human-related or animal-related patterns in image or video data
    • G06V40/10—Human or animal bodies, e.g. vehicle occupants or pedestrians; Body parts, e.g. hands
    • G06V40/12—Fingerprints or palmprints
    • G06V40/13—Sensors therefor
    • G06V40/1318—Sensors therefor using electro-optical elements or layers, e.g. electroluminescent sensing
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B30/00—Optical systems or apparatus for producing three-dimensional [3D] effects, e.g. stereoscopic images
    • G02B30/20—Optical systems or apparatus for producing three-dimensional [3D] effects, e.g. stereoscopic images by providing first and second parallax images to an observer's left and right eyes
    • G02B30/26—Optical systems or apparatus for producing three-dimensional [3D] effects, e.g. stereoscopic images by providing first and second parallax images to an observer's left and right eyes of the autostereoscopic type
    • G02B30/30—Optical systems or apparatus for producing three-dimensional [3D] effects, e.g. stereoscopic images by providing first and second parallax images to an observer's left and right eyes of the autostereoscopic type involving parallax barriers
    • G02B30/32—Optical systems or apparatus for producing three-dimensional [3D] effects, e.g. stereoscopic images by providing first and second parallax images to an observer's left and right eyes of the autostereoscopic type involving parallax barriers characterised by the geometry of the parallax barriers, e.g. staggered barriers, slanted parallax arrays or parallax arrays of varying shape or size

Definitions

  • the embodiments of the present application relate to the field of fingerprint identification, and more particularly, to a fingerprint identification device and an electronic device.
  • the size of the current lens-type under-screen optical fingerprint products is difficult to adapt to this trend, and it is urgent to develop in the direction of thinner thickness, smaller volume and higher degree of integration.
  • the image contrast imaged by the collimation hole is related to the depth of the collimation hole, and a relatively large depth is required to achieve high imaging quality, and the light utilization rate of this scheme is low.
  • the solution using microlens focusing is limited by the process and lens surface shape. Although the light utilization rate is high, the signals are easily aliased, resulting in low signal contrast and low imaging quality of fingerprints.
  • the embodiments of the present application provide a fingerprint identification device and an electronic device, which can improve the quality of fingerprint imaging while realizing the thinning of the fingerprint identification device.
  • a fingerprint identification device suitable for use under a display screen to realize off-screen optical fingerprint identification
  • the fingerprint identification device includes a plurality of fingerprint identification units distributed in an array, each of the plurality of fingerprint identification units.
  • Each fingerprint identification unit includes: a plurality of pixel units; a micro-lens, arranged above the plurality of pixel units; a multi-layer light-blocking layer, arranged between the micro-lens and the plurality of pixel units, the multi-layer light-blocking layer
  • Each light-blocking layer is provided with light-passing holes corresponding to the plurality of pixel units to form a plurality of light guide channels corresponding to the plurality of pixel units one-to-one; wherein, the plurality of pixel units are respectively Used to receive a plurality of fingerprint light signals reflected or scattered from the finger above the display screen, converged by the micro lens, and then transmitted through the plurality of light guide channels, and the plurality of fingerprint light signals are used to detect the finger fingerprint information for fingerprint identification
  • one microlens in the fingerprint identification device corresponds to multiple pixel units, which can increase the amount of light entering the fingerprint identification device, reduce the exposure time, and increase the field of view.
  • the object-side beam of the fingerprint can be imaged non-positively (ie, oblique light imaging), which can improve the identification effect of dry fingers and expand the optical system.
  • the object-square numerical aperture and the thickness of the optical path design of the pixel array can be shortened, and finally the thickness of the fingerprint identification device can be effectively reduced.
  • the parameters in the fingerprint identification device are constrained to meet certain conditions, so as to meet the requirements of image brightness and contrast.
  • the optical aperture D 2 and the maximum aperture CA of the microlens satisfy 0.3 ⁇ D 2 /CA ⁇ 1.3, so as to implement constraints and restrictions on the structure and parameters of the optical system of the fingerprint identification device. While realizing the ultra-thin fingerprint identification device, it can effectively The aliasing of the image is reduced, and the imaging has higher contrast and higher brightness, which can ultimately achieve better imaging effects for various targets, thereby improving the recognition accuracy.
  • the depth Z 2 between the lower surface of the intermediate light-blocking layer and the lower surface of the microlens and the depth between the lower surface of the bottom light-blocking layer and the lower surface of the microlens Z 1 satisfies 0.1 ⁇ Z 2 /Z 1 ⁇ 0.9.
  • the depth Z 2 between the lower surface of the intermediate light-blocking layer and the lower surface of the microlens and the depth Z2 between the lower surface of the bottom light-blocking layer and the lower surface of the microlens The depth Z 1 satisfies 0.1 ⁇ Z 2 /Z 1 ⁇ 0.5, the light-passing aperture D 2 of the light-passing area and the maximum aperture CA of the microlens satisfy 0.5 ⁇ D 2 /CA ⁇ 1, and the shape of the light-passing area is a round.
  • the depth Z 2 between the lower surface of the intermediate light-blocking layer and the lower surface of the microlens and the depth Z2 between the lower surface of the bottom light-blocking layer and the lower surface of the microlens satisfies 0.3 ⁇ Z 2 /Z 1 ⁇ 0.75
  • the light-passing aperture D 2 of the light-passing area and the maximum aperture CA of the microlens satisfy 0.5 ⁇ D 2 /CA ⁇ 0.8
  • the shape of the light-passing area is a Rounded rectangle or a petal shape.
  • the depth Z 2 between the lower surface of the intermediate light-blocking layer and the lower surface of the microlens and the depth Z2 between the lower surface of the bottom light-blocking layer and the lower surface of the microlens The depth Z 1 satisfies 0.65 ⁇ Z 2 /Z 1 ⁇ 0.9, the light-passing aperture D 2 of the light-transmitting area and the maximum aperture CA of the microlens satisfy 0.8 ⁇ D 2 /CA ⁇ 1.2, and the intermediate light blocking layer and the The light-transmitting small holes corresponding to the plurality of pixel units are a one-to-one corresponding plurality of independent small holes.
  • the clear aperture D 2 of the light clear region and the maximum aperture CA of the microlens satisfy 0.5 ⁇ D 2 /CA ⁇ 1.2.
  • the depth Z 2 between the lower surface of the intermediate light-blocking layer and the lower surface of the microlens and the depth between the lower surface of the bottom light-blocking layer and the lower surface of the microlens Z 1 satisfies 0.5 ⁇ Z 2 /Z 1 ⁇ 0.9.
  • the maximum diameter D 1 of each light-transmitting hole in the bottom light blocking layer and the maximum diameter CA of the microlens satisfy 0.02 ⁇ D 1 /CA ⁇ 0.4.
  • the maximum aperture D 1 of each light-passing hole in the underlying light-blocking layer and the maximum aperture CA of the microlens are further restricted. Satisfying 0.02 ⁇ D 1 /CA ⁇ 0.4, in order to implement constraints on the structure and parameters of the optical system of the fingerprint identification device, while realizing the ultra-thin fingerprint identification device, it can further reduce the influence of stray light on the image, reduce the image Aliasing, balancing the brightness and contrast of the image, and achieving better imaging effects for various targets including fingerprints, thereby further improving the performance of the fingerprint identification device and improving the accuracy of fingerprint identification. That is, it can further accurately meet the requirements of improving image brightness and contrast, and optimize image quality to a greater extent.
  • the maximum diameter D 1 of each light-passing hole in the underlying light blocking layer and the maximum diameter CA of the microlens satisfy 0.08 ⁇ D 1 /CA ⁇ 0.18.
  • the depth distance Z 1 between the radius of curvature ROC of the microlens and the lower surface of the underlying light blocking layer to the lower surface of the microlens satisfies 0.25 ⁇ ROC/Z 1 ⁇ 0.75.
  • radius of curvature ROC of the microlens and the depth distance Z1 between the lower surface of the underlying light blocking layer and the lower surface of the microlens satisfies the condition of 0.25 ⁇ ROC/ Z1 ⁇ 0.75 , comprehensively considering the focal point and The proportional relationship between the positions of the bottom light-blocking layer makes the target fingerprint light signals in each direction of the target fingerprint light signals in multiple directions focus or nearly focus on each pass light in the bottom light-blocking layer after being converged by the microlens. Small holes to improve image quality and recognition success rate.
  • the depth distance Z 1 between the radius of curvature ROC of the microlens and the lower surface of the underlying light blocking layer to the lower surface of the microlens satisfies 0.4 ⁇ ROC/Z 1 ⁇ 0.6.
  • each light-passing hole in the i-th light-blocking layer from bottom to top in the multilayer light-blocking layer satisfies 0 ⁇ S i /Z 1 ⁇ 1, where S i is the distance from the center of each light-passing hole in the i-th light-blocking layer to the center of the projection of the microlens on the i-th light-blocking layer.
  • the target fingerprint optical signals in multiple directions are more accurately transmitted to the corresponding light-passing holes through the light-passing holes in each light-blocking layer It can block light signals in non-target directions, reduce the impact of stray light on imaging, and further improve image quality.
  • the position of each light-transmitting hole in the i-th light-blocking layer satisfies 0.2 ⁇ S i /Z 1 ⁇ 0.5.
  • each light-transmitting small hole in the underlying light-blocking layer is a circular hole with the same size.
  • the arrangement period P b of the microlenses in the fingerprint identification device and the arrangement period P a of the pixel units in the fingerprint identification device satisfy 1 ⁇ P b /P a ⁇ 4.
  • P b /P a 2
  • one of the fingerprint identification units includes 4 pixel units.
  • P b /P a 3
  • one of the fingerprint identification units includes 9 pixel units.
  • the arrangement period P b of the microlenses in the fingerprint identification device satisfies 5 ⁇ m ⁇ P b ⁇ 40 ⁇ m.
  • the arrangement period P b of the microlenses in the fingerprint identification device satisfies 10 ⁇ m ⁇ P b ⁇ 30 ⁇ m.
  • the bottom light blocking layer is a metal wiring layer on the surface of the plurality of pixel units.
  • the fingerprint identification unit further includes: a protective layer; the protective layer is disposed above the bottom light blocking layer and integrated with the bottom light blocking layer and the plurality of pixel units.
  • the light-transmitting apertures of the plurality of light-guiding channels in the intermediate light-blocking layer overlap.
  • the shape of the light-transmitting area is a circle, a rectangle with rounded corners, or a petal shape.
  • the fingerprint identification unit further includes: an infrared filter layer, where the infrared filter layer is a filter layer coated and grown on the surface of the sensor chip for blocking infrared light.
  • the fingerprint identification unit further includes: an adhesive layer, the adhesive layer is a flat transparent layer coated on the surface of the infrared filter layer, and the intermediate light blocking layer is disposed on the adhesive layer above.
  • the fingerprint identification unit further includes: a first transparent medium layer disposed above the intermediate light-blocking layer and filling the light-transmitting small holes in the intermediate light-blocking layer.
  • the fingerprint identification unit further includes: a color filter layer disposed between the microlens and the first transparent medium layer, the color filter layer including a red filter layer, a blue filter layer light layer, green filter layer or white filter layer.
  • the light-transmitting apertures of the plurality of light-guiding channels in the intermediate light-blocking layer are independent of each other.
  • the intermediate light blocking layer is disposed on the upper surface of the protective layer.
  • the fingerprint identification unit further includes: a second transparent medium layer disposed above the intermediate light-blocking layer and filling the light-transmitting small holes in the intermediate light-blocking layer.
  • the fingerprint identification unit further includes: an infrared filter layer, the infrared filter layer is a filter layer coated on the surface of the second transparent medium layer for blocking infrared light.
  • the fingerprint identification unit further includes: a color filter layer disposed above the infrared filter layer, and the color filter layer includes a red filter layer, a blue filter layer, and a green filter layer layer or white filter layer.
  • the fingerprint identification unit further includes: a third transparent medium layer disposed between the microlens and the color filter layer.
  • 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, where the fingerprint identification device is disposed below the display screen to achieve Under-screen optical fingerprint recognition.
  • the above fingerprint identification device is provided in the electronic equipment, and by setting one microlens in the fingerprint identification device to correspond to a plurality of pixel units, the light input amount of the fingerprint identification device can be increased, the exposure time can be reduced, and the field of view can be increased.
  • the object-side beam of the fingerprint can be imaged non-positively (ie, oblique light imaging), which can improve the identification effect of dry fingers and expand the optical system.
  • the object-square numerical aperture and the thickness of the optical path design of the pixel array can be shortened, and finally the thickness of the fingerprint identification device can be effectively reduced.
  • the parameters in the fingerprint identification device are constrained to meet certain conditions, so as to meet the requirements of image brightness and contrast.
  • the optical aperture D 2 and the maximum aperture CA of the micro-lens satisfy 0.3 ⁇ D 2 /CA ⁇ 1.3, so as to implement constraints on the structure and parameters of the optical system of the fingerprint identification device. While realizing the ultra-thin fingerprint identification device, it can effectively The aliasing of the image is reduced, and the imaging has higher contrast and greater brightness, which can ultimately achieve better imaging effects for various targets, thereby improving the recognition accuracy. By improving the fingerprint recognition performance of the fingerprint recognition device, the fingerprint recognition performance of the electronic device is improved.
  • 1 and 2 are a schematic cross-sectional view and a schematic top view of a fingerprint identification device.
  • 3 to 5 are schematic cross-sectional views, schematic top views, and schematic perspective views of another fingerprint identification device according to an embodiment of the present application.
  • 6 to 8 are schematic cross-sectional views, schematic top views, and schematic perspective views of another fingerprint identification device according to an embodiment of the present application.
  • FIG. 9 is a schematic diagram of the arrangement of a pixel array in a fingerprint identification device according to an embodiment of the present application.
  • FIG. 10 is a schematic diagram of light-transmitting small holes in the intermediate light-blocking layer corresponding to a plurality of pixel units of a fingerprint identification unit under ideal conditions.
  • FIG. 11 is a schematic cross-sectional view of a fingerprint identification unit according to an embodiment of the present application.
  • FIG. 12 is a schematic cross-sectional view of another fingerprint identification unit according to an embodiment of the present application.
  • FIG. 13 to FIG. 17 are schematic diagrams of light-transmitting regions of the intermediate light-blocking layer according to the embodiments of the present application.
  • FIG. 18 is a curve of the contrast and brightness of the image collected by the fingerprint identification device according to the embodiment of the present application as a function of D 2 /CA.
  • FIG. 19 is a schematic diagram of images acquired under three D 2 /CA constraints according to an embodiment of the present application.
  • FIG. 20 is a schematic cross-sectional view of a fingerprint identification device under different D 2 /CA constraints according to an embodiment of the present application.
  • FIG. 21 is a schematic cross-sectional view of a fingerprint identification device under different D 2 /D 1 constraints according to an embodiment of the present application.
  • FIG. 22 shows a schematic cross-sectional view of a fingerprint identification device according to an embodiment of the present application.
  • FIG. 23 shows a schematic cross-sectional view of another fingerprint identification device according to an embodiment of the present application.
  • Fig. 24 shows a curve of the contrast and brightness of an image captured by the fingerprint identification device as a function of the shape of the light-transmitting area of the intermediate light-blocking layer.
  • FIG. 25 shows a schematic diagram of images captured under the shape of the light-passing area of the four types of intermediate light-blocking layers.
  • FIG. 26 shows a schematic block diagram of an electronic device according to an embodiment of the present application.
  • the screen ratio of electronic product screens is getting higher and higher, and full screen has become the development trend of many electronic products.
  • photosensitive devices in electronic products such as fingerprint recognition, front camera, etc.
  • the most widely used under-screen fingerprint recognition technology is the under-screen optical fingerprint recognition technology. Due to the particularity of the under-screen optical fingerprint device, it is required that the light with the fingerprint signal can pass through the screen to the fingerprint sensor below, and then obtain the fingerprint signal.
  • 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 by the embodiments of the present application can be applied to portable or mobile computing devices such as smart phones, tablet computers, and game devices, as well as electronic databases, automobiles, and bank automated teller machines (automated teller machines, ATMs). ) and other electronic devices, but the embodiments of the present application are not limited to this, and the embodiments of the present application may be applied to other mobile terminals or other electronic devices with display screens; more specifically, in the above electronic devices, the fingerprint identification device may Specifically, it is an optical fingerprint device, which can be arranged in a partial area or all areas below the display screen, thereby forming an under-display optical fingerprint system.
  • an under-screen fingerprint identification device includes an optical component, and the optical component may be disposed above the optical fingerprint sensor, which may include a filter layer, an optical path guiding structure, and other optical elements.
  • the pinhole can guide the light signal reflected by the finger to the sensor chip under the display screen for fingerprint recognition.
  • the smaller the aperture of the pinhole the higher the resolution.
  • the size of the small hole cannot be further reduced, thus limiting the improvement of its resolution.
  • Another method uses optical lenses for imaging, which uses spherical or aspherical lenses to condense light to improve imaging resolution.
  • the lens imaging can guide more optical signals to reach the sensor chip compared to the method of pinhole imaging.
  • the fingerprint identification device can include a microlens array and a light blocking layer, and the microlens array can be provided with Above the light blocking layer, the light blocking layer is provided with an array of small holes.
  • the microlens array is used to focus the light signal reflected by the finger to the small hole array, and the small hole array can guide the received light signal to the fingerprint sensor chip under the light blocking layer.
  • the fingerprint sensor chip can perform fingerprint recognition according to the received light signal.
  • the microlenses have the function of concentrating light, thereby improving the resolution of the images generated by the fingerprint sensor chip.
  • the small hole array has the function of screening optical signals. For example, the small hole array does not allow interference light signals with large angles to pass through, but only allows light signals within a desired specific angle range to pass through, so as to improve the fingerprint recognition effect.
  • the sensing array in the fingerprint identification 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.
  • the optical fingerprint sensor in the fingerprint identification device may also be referred to as a fingerprint sensor or a fingerprint sensor chip.
  • the fingerprint identification device in the embodiments of the present application may also be referred to as an optical fingerprint device, an optical fingerprint identification module, a fingerprint identification module, a fingerprint collection device, etc., and the above terms can be interchanged with each other.
  • FIG. 1 and 2 show a schematic cross-sectional view and a schematic top view of a typical fingerprint identification device.
  • the fingerprint identification device 100 includes a microlens array 110 , at least one light blocking layer 120 and a pixel array 130 .
  • the microlens array 110 is located directly above the pixel array 130 and at least one light blocking layer 120 , and one microlens 111 corresponds to one pixel unit 131 , that is, each microlens 111 in the microlens array 110 passes the received light through at least one pixel unit 111 .
  • the small holes 1201 of the light blocking layer 120 are focused into the pixel units 131 corresponding to the same microlens 111 .
  • the optical signal received by each microlens 111 is mainly a fingerprint optical signal incident perpendicular to the microlens array 110 after being reflected or scattered by the finger above the display screen.
  • the pixel units 131 in the pixel array 130 are arranged periodically, and the photosensitive area 1311 of each pixel unit 131 in the pixel array 130 is arranged at the center of the same pixel unit, so as to improve the sensitivity of the photosensitive area. duty cycle.
  • the plurality of microlenses 111 in the microlens array 110 correspond to the plurality of pixel units 131 in the pixel array 130 one-to-one, and the photosensitive regions 1311 of the plurality of pixel units 131 in the pixel array 130 are periodically arranged and uniformly distributed.
  • the photosensitive area of the pixel array 130 is affected by the size of the microlens array 110 , and the thickness of the fingerprint identification device 100 is relatively large, thereby increasing the processing difficulty, cycle and cost of the optical path of the fingerprint identification device 100 .
  • the fingerprint identification device 100 since a plurality of microlenses are close to each other, light may be incident on the chip surface from other microlenses, thus affecting the imaging effect. And since the microlenses and the pixel units are in one-to-one correspondence, the theoretical maximum signal amount that a pixel unit can receive is the energy of the collimated light received when the microlenses occupy the area of one pixel unit. This receiving method limits the further improvement of the image signal volume. Under weak illumination, the signal-to-noise ratio is low, which affects the image quality.
  • 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 100 is poor, and the image is blurred to the point where the fingerprint lines cannot be distinguished. Fingerprint recognition performance is poor.
  • the present application proposes a fingerprint identification device 200, which adopts one or more light-blocking layers provided with an array of pinholes in combination with a microlens array, and each microlens corresponds to a plurality of pixel units.
  • Each pixel unit of the plurality of pixel units can receive the oblique collimated light converged by the entire microlens, but the received incident light has different oblique directions for the plurality of pixel units corresponding to one microlens.
  • Eventually multiple images can be taken from the image chip array, each made up of pixel cells received in the same oblique orientation.
  • This receiving method can greatly improve the contrast and brightness of the image, and can also achieve other application directions such as expanding the size of the object-side field of view.
  • 3 to 5 show a schematic cross-sectional view, a schematic top view, and a schematic perspective view of the fingerprint identification device 200 .
  • the fingerprint identification device 200 is suitable for use under the display screen to realize off-screen optical fingerprint identification.
  • the fingerprint identification device 200 includes a plurality of fingerprint identification units 201 distributed in a square array. As shown in Figures 3 to 5, in the fingerprint identification device 200, each fingerprint identification unit 201 includes:
  • microlens 211 arranged above the plurality of pixel units
  • At least one light-blocking layer is disposed between the plurality of pixel units and the microlenses 211, and each light-blocking layer in the at least one light-blocking layer is provided with light-passing holes corresponding to the plurality of pixel units to form a plurality of light guide channels corresponding to the plurality of pixel units one-to-one;
  • the plurality of pixel units are respectively used to receive the plurality of fingerprint optical signals reflected or scattered from the finger above the display screen, converged by the microlens 211, and then transmitted through the plurality of transmission channels.
  • the plurality of fingerprint optical signals are used for It is used to detect the fingerprint information of the finger for fingerprint identification.
  • the transmittance of each light-blocking layer in the at least one light-blocking layer to light in a specific wavelength band is less than a preset threshold (for example, 20%), so as to avoid corresponding light pass.
  • each fingerprint identification unit 201 of the plurality of fingerprint identification units in the fingerprint identification device form a microlens array 210 .
  • a pixel array 230 is formed by a plurality of pixel units included in each fingerprint identification unit 201 of the plurality of fingerprint identification units in the fingerprint identification device.
  • the light blocking layer in each fingerprint identification unit 201 is actually a partial light blocking layer.
  • the fingerprint identification device in the embodiments of the present application will be described below with a fingerprint identification unit 201 as a unit, and the partial light blocking layer in the fingerprint identification unit 201 is simply referred to as a light blocking layer.
  • the fingerprint identification unit 201 includes a multi-layer light blocking layer, a bottom light blocking layer 221 and a middle light blocking layer 222, wherein the bottom light blocking layer 221 is the light blocking layer closest to the pixel unit, and the middle light blocking layer Layer 222 is a light blocking layer other than the bottom light blocking layer.
  • one microlens corresponds to 4 pixel units.
  • the fingerprint identification unit 201 in FIG. 3 is actually the line connecting the fingerprint identification unit 201 in FIG. 5 along the centers of the first pixel unit 231 and the third pixel unit 233
  • FIG. 4 is a top view of FIG. 5 .
  • a first pixel unit 231 , a second pixel unit 232 , a third pixel unit 233 and a fourth pixel unit 234 are correspondingly disposed below the first microlens 211 , and the four pixel units are located in four different Orientation to the bottom of the light guide channel.
  • each pixel unit is provided with a photosensitive area (Active Area, AA) for respectively receiving the four fingerprint light signals passing through the four light guide channels and converting them into corresponding electrical signals.
  • the photosensitive area can be the area where the photodiode is located in the pixel unit, that is, the area in the pixel unit that receives the light signal, and other areas in the pixel unit can be used for setting other circuits in the pixel unit and for the arrangement of wiring between pixels .
  • the fourth photosensitive regions 2341 are all disposed at the bottom of the above-mentioned four light guide channels in different directions.
  • the four light guide channels corresponding to the first microlenses 211 are provided with four light guide channels on both the bottom light blocking layer 221 and the middle light blocking layer 222 .
  • FIG. 3 to FIG. 5 the four light guide channels corresponding to the first microlenses 211 are provided with four light guide channels on both the bottom light blocking layer 221 and the middle light blocking layer 222 .
  • the bottom light-blocking layer 221 is provided with light-passing holes 2211 corresponding to the first pixel units 231
  • the middle light-blocking layer 222 is provided with light-passing holes 2221 corresponding to the first pixel units 231 .
  • the light-passing holes 2211 and the light-passing holes 2221 are both corresponding to the light-passing holes on the first light-guiding channel of the first pixel unit 231 , in other words, the light-passing holes 2211 and the light-passing holes 2221 are formed Corresponding to the first light guide channel of the first pixel unit 231 .
  • the centers of the light-transmitting holes 2211 and the light-transmitting holes 2221 may be on a straight line, and the direction of the straight line is the direction of the first light guide channel.
  • the oblique light signal 21 in the first direction is condensed by the first microlens 211, it passes through the first light guide channel to the first photosensitive area 2311 in the first pixel unit 231, while the light signal in other directions (for example, the dotted line in the figure) The light signal shown) is blocked in the light blocking layer and cannot be transmitted to the pixel unit.
  • the inclined light signal 21 in the first direction may be a fingerprint inclined light signal in the first direction that passes through the display screen after being reflected or scattered by the finger above the display screen and reaches the first microlens 211 .
  • the oblique light signal 21 can be used to detect fingerprint information.
  • the oblique fingerprint optical signals in other directions are condensed by the first microlens 211 , and then transmitted to the corresponding pixel unit after passing through the light guide channel formed by the light-passing aperture.
  • the oblique light signal 23 in the third direction is condensed by the first microlens 211 , it passes through the third light guide channel to the first photosensitive area 2311 in the third pixel unit 233 .
  • the four light-guiding channels corresponding to each microlens are provided with four light-passing holes in the bottom light blocking layer 221, and the four light-passing holes correspond to four pixel units.
  • FIG. 6 to 8 show a schematic cross-sectional view, a schematic top view, and a schematic perspective view of another fingerprint identification device.
  • the fingerprint identification unit 201 in FIG. 6 is actually a cross-sectional view of the fingerprint identification unit 201 in FIG. 8 along the line connecting the centers of the first pixel unit 231 and the third pixel unit 233
  • FIG. 7 is a top view of FIG. 8 .
  • the bottom light-blocking layer 221 is provided with a light-passing hole 2211 corresponding to the first pixel unit 231
  • the middle light-blocking layer 222 is provided with a large light-passing hole 2221 .
  • the light apertures 2221 correspond to 4 pixel units.
  • the light passing holes 2211 and the light passing holes 2221 form a first light guide channel corresponding to the first pixel unit 231 .
  • the centers of the light-transmitting holes 2211 and the light-transmitting holes 2221 may be on a straight line, and the direction of the straight line is the direction of the first light guide channel.
  • the oblique light signal 21 in the first direction After the oblique light signal 21 in the first direction is condensed by the first microlens 211, it passes through the first light guide channel to the first photosensitive area 2311 in the first pixel unit 231, while the light signal in other directions (for example, the dotted line in the figure) The light signal shown) is blocked in the light blocking layer and cannot be transmitted to the pixel unit.
  • the four pixel units corresponding to each microlens in the fingerprint identification device 200 receive four different directions of oblique light signals through four light guide channels in different directions.
  • the pixel array 230 in the fingerprint identification device 200 can generate four fingerprint images based on the received optical signals in four different directions, thereby obtaining a high-resolution fingerprint image, so as to improve the fingerprint identification effect.
  • Fig. 9 shows a schematic diagram of the arrangement of a pixel array 230, as shown in Fig. 9, wherein "1" represents a pixel unit for receiving an oblique light signal in a first direction, and “2" represents a pixel unit for receiving an oblique light signal in a second direction
  • all the pixel units indicated by "1” can be used to generate the first fingerprint image, and all the pixel units indicated by “2” can be used to generate the second fingerprint image, respectively, All the pixel units indicated by “3” can be used to generate the third fingerprint image respectively, and all the pixel units indicated by "4" can be used to generate the fourth fingerprint image respectively, that is, a total of 4 fingerprint images can be generated.
  • the four fingerprint images can be used for fingerprint identification individually, or can also be combined into a high-resolution fingerprint image, thereby improving the identification effect of the fingerprint identification device.
  • the four fingerprint images are generated by oblique light signals in different directions, the four fingerprint images correspond to different object-side imaging areas, and other application directions such as expanding the object-side field of view can also be realized.
  • the four pixel units corresponding to a single microlens can simultaneously receive optical signals in four directions, thereby increasing the light input of the fingerprint identification device, reducing the exposure time, and increasing the field of view.
  • the object-side beam of the fingerprint can be imaged non-positively (ie, oblique light imaging), which can improve the identification effect of dry fingers and expand the optical system.
  • the object-square numerical aperture and the thickness of the optical path design of the pixel array can be shortened, and finally the thickness of the fingerprint identification device can be effectively reduced.
  • the corresponding four light-passing holes (aperture holes) in the intermediate light blocking layer of the four pixel units coincide with each other (shown by the dotted line in the figure).
  • the increase in the area of the light-passing aperture will lead to the entry of stray light and the decrease of collimation.
  • the lower-cost technology cannot obtain higher graphics precision. Therefore, the embodiments of the present application provide several technical solutions, which can obtain higher aperture shape accuracy of the intermediate light blocking layer and better image quality under relatively economical conditions.
  • FIGS. 11 and 12 respectively show schematic cross-sectional views of two fingerprint identification units 201
  • FIGS. 13 to 15 are schematic top views of FIG. 11
  • FIG. 16 is a schematic top view of FIG. 12 .
  • the light-transmitting small holes in the intermediate light blocking layer 222 of the four light-guiding channels overlap, and are one large circular through-hole.
  • the advantage of a large circular via is that manufacturing accuracy requirements are lower.
  • the opening of the intermediate light-blocking layer can be made by photolithography or coating methods. Since the circle is a simple pattern, it can obtain a complete pattern with a lower lithography resolution regardless of whether it is exposed by positive or negative adhesive. .
  • the light-transmitting holes in the intermediate light-blocking layer 222 of the four light-guiding channels overlap, and are a rounded rectangular through-hole.
  • rounded rectangular through holes can further reduce the stray light leakage area without increasing the difficulty in the process, whether it is achieved by using positive glue, negative glue or coating.
  • the light-transmitting holes in the middle light-blocking layer 222 of the four light-guiding channels overlap, and are one petal-shaped through-hole.
  • the petal-shaped number of petals is 4, which is composed of 4 overlapping openings.
  • the shape of the petal is formed by the overlapping of the four openings, and its shape is exactly like the petal.
  • the shape of the opening can be a circle, an ellipse or other shapes.
  • a fingerprint identification unit includes 9 pixel units, that is, 9 light guide channels
  • the number of petals in the petal shape is 9, which is composed of 9 pixels.
  • the number of petals in the petal shape may be related to the pixel units included in a fingerprint identification unit.
  • Fig. 15 shows the petal-shaped light-passing holes formed by partially overlapping/intersecting four circular openings.
  • petal-shaped through-holes Compared with rounded rectangular through-holes and round large through-holes, the advantage of petal-shaped through-holes is to further reduce unnecessary light leakage areas, maximize the collimation of incident light, and increase image contrast, but it requires Higher lithography resolution will increase the cost if it is fabricated by coating.
  • the light-transmitting holes in the intermediate light-blocking layer 222 of the four light-guiding channels are independent of each other.
  • the small holes of the intermediate light blocking layer are not staggered, which has obvious effects on improving the collimation of incident light and improving the crosstalk of strong light, but it requires high processing resolution and high material requirements. It is possible for the thin walls to break between the small holes.
  • D2 may be defined as the light-passing aperture of the light-passing area formed by the light-passing holes corresponding to the four pixel units in the intermediate light blocking layer 222 , wherein the light-passing aperture D2 may be is the distance between the two farthest points in the light-transmitting area on the plane where the intermediate light-blocking layer is located.
  • D2 can be the diameter of a circle on the intermediate light-blocking layer 222 as shown in FIG. The diagonal of the rounded rectangle on the intermediate light-blocking layer 222 shown in FIG. 14 , or the largest dimension passing through the center of the petal shape on the intermediate light-blocking layer 222 as shown in FIG. 15 , or the diagonal line shown in FIG. 16 The farthest distance between two diagonal apertures on the intermediate light blocking layer 222 is shown.
  • CA can also be defined as the maximum diameter of the microlens 211 , for example, CA can be the maximum width in the cross section of the microlens 211 in the horizontal direction.
  • the microlens 211 may be a spherical lens or an aspherical lens, the upper surface of which is spherical or aspherical, and the lower surface is a horizontal plane, and the maximum diameter CA of the microlens 211 may be the maximum width of the lower surface.
  • the microlens 211 may be a spherical lens, the lower surface of which is a circular horizontal plane, and the maximum diameter CA of the microlens 211 is the diameter of the circular horizontal plane.
  • the embodiments of the present application only show four shapes of openings of the intermediate light blocking layer 222, the embodiments of the present application should not be limited thereto, and the shapes of the light-transmitting regions of the intermediate light blocking layer 222 may also be as shown in the figure.
  • the special shape shown in 17, that is, the irregular shape, D2 is defined as shown in the figure.
  • the light-clearing aperture D 2 of the light-transmitting region and the maximum aperture CA of the microlens 211 satisfy 0.3 ⁇ D 2 /CA ⁇ 1.3. It can be understood that when the fingerprint identification device includes multiple intermediate light-blocking layers, any intermediate light-blocking layer may satisfy the value range of D 2 /CA, as well as other parameter ranges related to the intermediate light-blocking layer. It can also be that the multiple intermediate light-blocking layers all meet the relevant parameter ranges.
  • Figure 18 shows a graph of image contrast and brightness versus D2/CA.
  • Figure 19 shows a schematic diagram of images acquired under three D2/CA constraints. It can be understood that the image contrast characterizes the difference in the degree of light and dark in the image, and can also be understood as the contrast of the image.
  • the parameters in the fingerprint identification device are constrained to meet certain conditions, so as to meet the requirements of image brightness and contrast.
  • the intermediate light blocking layer can be constrained
  • the light-passing aperture D2 of the middle light - passing area and the maximum aperture CA of the microlens satisfy 0.3 ⁇ D2 / CA ⁇ 1.3 . If D2/CA is too small, the light entering the light-passing area in the intermediate light-blocking layer is less. , it may cause the image to become darker and the noise to increase; if the D 2 /CA is too large, it may cause stray light to enter, thereby affecting the image clarity. If D 2 /CA is within the range constrained by this application, the aliasing of the image can be effectively reduced during imaging, the imaging has higher contrast and higher brightness, and ultimately better imaging effects for various targets can be achieved , thereby improving the recognition accuracy.
  • Z i may be defined as the depth from the bottom surface of the i-th light blocking layer to the bottom surface of the microlens 211 from bottom to top.
  • Z 1 is defined as the depth from the lower surface of the underlying light blocking layer 221 to the lower surface of the microlenses 211
  • Z 2 is defined as the depth from the lower surface of the intermediate light blocking layer 222 to the microlenses 211 the depth between the lower surfaces.
  • the depth Z 2 between the lower surface of the intermediate light blocking layer 222 and the lower surface of the microlens 211 and the depth Z 1 between the lower surface of the underlying light blocking layer 221 and the lower surface of the microlens 211 may also be constrained 0.1 ⁇ Z 2 /Z 1 ⁇ 0.9 is satisfied.
  • the intermediate light-blocking layer 222 is relatively close to the microlens 211 , ideally, the light-passing holes required by each pixel unit in the intermediate light-blocking layer 222 are relatively close to each other. Since the offset of the microlens 211 is small, 0.5 ⁇ D 2 /CA ⁇ 1 can be further restricted, which can be realized by using a circular large through hole with lower process difficulty, which better limits the incidence of stray light, thereby Ensure image brightness and contrast under relatively economical conditions.
  • each pixel unit needs to pass light in the intermediate light-blocking layer 222 .
  • the offset of the small hole relative to the microlens 211 is gradually increased.
  • it can be further constrained to 0.5 ⁇ D 2 /CA ⁇ 0.8, which can be realized by using a rounded rectangular through hole or a petal-shaped through hole with moderate technological difficulty.
  • the incident of stray light is reduced as much as possible on the premise of not reducing the aperture of light, and better image brightness and contrast are obtained.
  • one microlens corresponds to 4 pixel units as an example, the structure of the fingerprint identification device and the fingerprint imaging principle are described.
  • one The microlenses may also correspond to 2, 3, or more than 4 pixel units, for example, 9, 16, etc. pixel units.
  • the embodiment of the present application does not limit the number of pixel units in the fingerprint identification unit.
  • each fingerprint identification unit includes 9 pixel units, that is, one microlens corresponds to 9 pixel units
  • the underlying light-blocking layer may also include 9 light-passing holes, wherein, one light-passing hole in the bottom light-blocking layer corresponds to one pixel unit.
  • the intermediate light-blocking layer only includes one light-passing hole, that is, one microlens corresponds to one light-passing hole of the intermediate light-blocking layer, and one light-passing hole of the intermediate light-blocking layer corresponds to 9 holes of the bottom light-blocking layer.
  • There are 9 light-passing holes, and the 9 light-passing holes in the bottom light blocking layer correspond to the 9 pixel units one-to-one.
  • the intermediate light-blocking layer includes 9 light-passing holes, that is, one microlens corresponds to the 9 light-passing holes in the intermediate light-blocking layer, and the 9 light-passing holes in the intermediate light-blocking layer are connected to the bottom light-blocking layer.
  • the 9 light-passing holes in the bottom layer correspond one-to-one
  • the 9 light-passing holes in the bottom light-blocking layer correspond one-to-one with the 9 pixel units.
  • each fingerprint identification unit includes 16 pixel units, that is, one microlens corresponds to 16 pixel units
  • the underlying light-blocking layer may also include 16 light-passing holes, Wherein, one light-passing hole in the bottom light-blocking layer corresponds to one pixel unit.
  • the intermediate light-blocking layer only includes one light-passing hole, that is, one microlens corresponds to one light-passing hole of the intermediate light-blocking layer, and one light-passing hole of the intermediate light-blocking layer corresponds to 16 holes of the bottom light-blocking layer.
  • the 16 light-passing holes in the bottom light blocking layer there are 16 light-passing holes in the bottom light blocking layer, and the 16 light-passing holes in the bottom light blocking layer correspond to the 16 pixel units one-to-one.
  • the intermediate light-blocking layer includes 16 light-passing holes, that is, one microlens corresponds to the 16 light-passing holes in the intermediate light-blocking layer, and the 16 light-passing holes in the intermediate light-blocking layer are connected to the bottom light-blocking layer.
  • the 16 light-passing holes of the bottom layer correspond one-to-one
  • the 16 light-passing holes of the bottom light-blocking layer correspond to the 16 pixel units one-to-one.
  • the shape of the light-passing hole may be a circle, a rounded rectangle or a petal shape.
  • the foregoing related content please refer to the foregoing related content, which will not be repeated here.
  • A P b /P a , where P b is defined as the arrangement period of multiple microlenses in the fingerprint identification device, and P a is defined as the number of pixel units in the fingerprint identification device. Arrange the cycle.
  • a plurality of microlenses therein form a microlens array, wherein a plurality of pixel units form a pixel array, and on the horizontal plane, the arrangement of the plurality of microlenses in the X direction and the Y direction
  • the period is P b
  • the arrangement period of the plurality of pixel units in the X direction and the Y direction is P a .
  • the horizontal plane is parallel to the plane where the display screen is located
  • the vertical plane is perpendicular to the plane where the display screen is located.
  • D 1 is defined as the maximum diameter of each light-transmitting hole in the underlying light-blocking layer.
  • D 1 represents the diameter of the light-passing holes.
  • D 1 represents the distance between the opposite corners of the light-transmitting small holes.
  • the shapes of the plurality of light-transmitting holes in the underlying light-blocking layer may be the same or different.
  • the shapes of the plurality of light-transmitting small holes in the underlying light-blocking layer are consistent, that is, the plurality of light-transmitting small holes may all be circular small holes, rounded rectangular small holes or rectangular small holes.
  • the shapes of the plurality of light-transmitting small holes in the underlying light blocking layer are inconsistent, that is, the plurality of light-transmitting small holes may include at least two of circular small holes, rounded rectangular small holes and rectangular small holes.
  • the microlenses 211 in the fingerprint identification unit 201 correspond to 4 pixel units
  • the microlenses 211 correspond to the 4 light-passing holes in the bottom light blocking layer 221
  • the four light-passing holes may include three circles.
  • Shaped light holes and 1 rectangular hole, or 4 round light holes can include 3 round light holes and 1 rounded rectangular hole
  • 4 light holes can include 2
  • a circular light-passing hole, a rectangular hole and a rounded rectangular hole, etc., the shapes of the 4 light-passing holes can be combined arbitrarily, but considering the complexity of the process and the process steps, the preferred light-passing hole shape remains the same.
  • the sizes of the plurality of light-transmitting holes in the underlying light-blocking layer may be the same or different.
  • at least two of the plurality of light passing holes have different diameters.
  • each of the plurality of light passing holes has the same diameter.
  • the plurality of light-transmitting small holes in the bottom light-blocking layer are circular small holes with uniform diameters.
  • the light-transmitting holes in the bottom light blocking layer are circular light-transmitting holes, rounded rectangular holes or rectangular holes, which have good symmetry and have symmetry for optical signals in all directions. Therefore, it can improve the balance of the image in all directions, thereby improving the image quality.
  • the maximum diameter D 1 of each light-passing hole in the underlying light blocking layer 221 and the maximum diameter CA of the microlens may be constrained to satisfy 0.02 ⁇ D 1 /CA ⁇ 0.4.
  • each light-passing hole in the underlying light-blocking layer under the current microlens can well block the stray light conducted by the adjacent microlenses and reduce image aliasing, thereby reducing image aliasing. Improve the contrast of imaging, or improve the contrast of the image.
  • each light-passing hole in the underlying light-blocking layer can pass through enough light signals to ensure the brightness of the imaging. Therefore, using The solutions of the embodiments of the present application can take into account both the image brightness and the image contrast, thereby improving the image quality and the recognition success rate.
  • the number of pixel units corresponding to the microlens in one fingerprint identification unit can be increased, so that the optical signal converged by the microlens can be more fully utilized, and the spatial sampling of the image can be improved. rate, thereby improving the brightness and contrast of the image, but this method will increase the difficulty of the manufacturing process and increase the cost. Therefore, using the technical solutions of the embodiments of the present application, on the basis of considering the manufacturing process and cost, the parameters in the fingerprint identification device are constrained to meet certain conditions, and the requirements of image brightness and contrast are met.
  • 0.12 ⁇ D 1 /CA ⁇ 0.14, for example: D 1 /CA 0.12, 0.13 or 0.14, or D 1 /CA can also be any value between 0.12 and 0.14, which is not done in this embodiment of the present application Specific restrictions.
  • the radius of curvature ROC of the microlens 211 and the depth distance Z 1 between the lower surface of the underlying light blocking layer 221 and the lower surface of the microlens 211 satisfies 0.25 ⁇ ROC/Z 1 ⁇ 0.75.
  • the imaging effect is optimal at this time, and the image brightness is taken into account. while improving image contrast.
  • the depth distance Z 1 between the radius of curvature ROC of the constraining microlens and the lower surface of the underlying light blocking layer to the lower surface of the microlens satisfies 0.25 ⁇ ROC/ Z1 ⁇ 0.75 .
  • the proportional relationship between the focal point of the microlens and the position of the underlying light-blocking layer is comprehensively considered, so that each light-passing hole in the underlying light-blocking layer meets or is close to the above conditions, so as to improve image quality and recognition success rate.
  • the radius of curvature ROC of the microlens can be calculated by the following formula:
  • MLH is the height of the microlens, that is, the height from the vertex of the microlens to its lower surface
  • CA is the maximum diameter of the microlens.
  • the radius of curvature of the aspheric lens also has its calculation method.
  • the specific calculation method please refer to the calculation method in the related art, which will not be discussed in detail here.
  • ROC/Z 1 0.4 ⁇ ROC/Z 1 ⁇ 0.6.
  • the position of each light-passing hole in each light-blocking layer may be constrained as follows: 0 ⁇ S i /Z 1 ⁇ 1, preferably, in some embodiments, 0.2 ⁇ S i /Z 1 ⁇ 0.5, where S i represents the offset of each light-passing aperture in the i-th light-blocking layer in the fingerprint identification unit from the center of the projection of the microlens on the i-th light-blocking layer.
  • the depth distance from the lower surface of the i-th light blocking layer to the lower surface of the microlens can be expressed as Z i .
  • the offset S i from the center of each light-passing hole in the i-th light-blocking layer to the center of the projection of the microlens on the i-th light-blocking layer may be the same or different. There is no specific limitation on this.
  • the target fingerprint optical signals in multiple directions are more accurately transmitted to the corresponding light-passing holes through the light-passing holes in each light-blocking layer It can block light signals in non-target directions, reduce the influence of stray light on imaging, and further improve image quality.
  • the constraint range of the S 1 /Z 1 can also be adjusted, and then the constraint range of the ROC/Z 1 can be adjusted according to the constraint range of the S 1 /Z 1 , thereby By adjusting the position of the light-passing holes in the bottom light-blocking layer, the angle of the desired target fingerprint light signal is adjusted, and then the curvature radius of the microlens and the depth from the bottom surface of the bottom light-blocking layer to the bottom surface of the microlens are adjusted. distance, so that the fingerprint identification device in the embodiment of the present application can receive oblique light signals of various angles while satisfying good imaging conditions, which is suitable for a wider range of application scenarios.
  • the depth distance Z 1 between the radius of curvature ROC of the microlens and the lower surface of the underlying light blocking layer to the lower surface of the microlens may be constrained to satisfy 0.25 ⁇ ROC/ Z1 ⁇ 0.75 , and the maximum aperture D 1 of each light-passing hole in the bottom light blocking layer and the maximum aperture CA of the microlens satisfy 0.02 ⁇ D1 /CA ⁇ 0.4. Combining the two constraints, it can further accurately meet the requirements of improving image brightness and Contrast requirements to maximize image quality.
  • the parameters of the bottom light-blocking layer can also be constrained to meet certain conditions and the parameters of the intermediate light-blocking layer to meet certain conditions, so that the requirements for improving image brightness and contrast can be further accurately met. Maximize image quality.
  • FIG. 22 shows a schematic cross-sectional view of another fingerprint identification device 200 .
  • the bottom light blocking layer 221 and the middle light blocking layer 222 in addition to the microlens 211 and its corresponding four pixel units, the bottom light blocking layer 221 and the middle light blocking layer 222, it also includes: a protective layer 241, the protective layer 241 is located above the bottom light blocking layer 221 .
  • the bottom light blocking layer 221 may be integrated with the pixel unit, that is to say, the bottom light blocking layer and the pixel unit may be integrated inside the fingerprint sensor chip of the fingerprint identification device, so that Internal components of the fingerprint sensor chip, optionally, the bottom light-blocking layer 221 may be a metal circuit layer located above the pixel unit in the sensor chip, that is, the bottom light-blocking layer may be the metal circuit layer of the pixel unit for transmitting electrical signals, Alternatively, the bottom light blocking layer 221 can also be other material layers with low visible light transmittance.
  • the above-mentioned protective layer 241 can also be a laminated structure in the sensor chip, which is formed on the surface of the sensor chip to protect the sensor chip from being polluted by external water vapor and samples, resulting in failure of the sensor performance.
  • the protective layer 241 includes, but is not limited to, silicon oxide and/or silicon nitride.
  • the protective layer 241 is also a transparent material layer with high transmittance for optical signals. By setting the height of the protective layer 211 , a certain focusing distance can be provided for the pixel units in the sensor chip.
  • the intermediate light blocking layer 222 is disposed on the upper surface of the sensor chip, that is, disposed on the upper surface of the protective layer 241 .
  • This arrangement can reduce the distance between the bottom light-blocking layer 221 and the middle light-blocking layer 222, and improve the light-guiding performance of the light-guiding channel formed in the two light-blocking layers.
  • the intermediate light blocking layer 222 may be a black polymer light absorbing material to absorb most of the light signals in the environment.
  • the fingerprint identification unit 201 further includes: a second transparent medium layer 242 , the second transparent medium layer 242 is disposed above the above-mentioned intermediate light-blocking layer 222 and fills the light-passing holes in the intermediate light-blocking layer 222 .
  • the second transparent medium layer 242 is also a medium layer formed of an optically high transmittance material.
  • the second transparent medium layer 242 can be formed above the intermediate light-blocking layer 222 by a semiconductor spin coating process and a curing process and fill the light-transmitting holes in the intermediate light-blocking layer 222.
  • the height of the layer 242 can also provide a certain focusing distance for the pixel units in the sensor chip.
  • the fingerprint identification unit 201 further includes: an infrared filter layer 250 for blocking infrared light and part of the red light, preventing the infrared light and part of the red light from entering the pixel unit and affecting the imaging effect.
  • an infrared filter layer 250 for blocking infrared light and part of the red light, preventing the infrared light and part of the red light from entering the pixel unit and affecting the imaging effect.
  • the infrared light in the environment is strong. If the strong infrared light enters the pixel unit, the signal of the pixel unit is easily saturated, and the infrared light easily penetrates the finger, forming the transmitted light of the finger. Part of the transmitted light will affect the imaging of the finger reflected light in the normal fingerprint identification process. For two reasons, the infrared light has a great influence on the fingerprint imaging, and it needs to be cut off by the infrared filter layer.
  • the infrared filter layer 250 includes a multi-layer inorganic material layer
  • the multi-layer inorganic material layer can be formed by coating the second transparent medium layer 242 by a coating process, and the coating process includes, but is not limited to, physical vapor phase Deposition (physical vapor deposition, PVD) coating method.
  • the multi-layer inorganic material layer can be a multi-layer inorganic material layer alternately grown by titanium dioxide/silicon dioxide (TiO 2 /SiO 2 ), or alternatively grown by niobium pentoxide/silicon dioxide (Nb 2 O 5 /SiO 2 ).
  • the multi-layer inorganic material layer or may also be other organic or inorganic materials used to cut off infrared light signals, which are not limited in the embodiments of the present application.
  • the fingerprint identification unit 201 further includes: a color filter layer 260, which is arranged above the infrared filter layer 250 and is used to pass the light signal of the target wavelength band and cut off the target.
  • the color filter layer can be realized by a semiconductor photolithography process.
  • the color filter layer includes, but is not limited to, a red filter layer, a blue filter layer, a green filter layer or a white filter layer for transmitting red light signals, blue light signals, green light signals or white light signal.
  • the pixel units in the fingerprint identification unit 201 receive color light signals through color light signals, which can be used for fingerprint anti-counterfeiting to determine true and false fingers. If the color filter layer is a white filter layer and transmits a white light signal, the pixel unit in the fingerprint identification unit 201 receives a white light signal, which can be used to generate a fingerprint image for fingerprint identification. Then, the fingerprint identification device provided by the embodiment of the present application can further perform fingerprint anti-counterfeiting judgment on the basis of fingerprint identification, thereby improving the success rate of fingerprint identification.
  • the color filter layer can be used to absorb the light signal reflected by the infrared filter layer below it, preventing the reflected light signal from being received by the human eye through the display screen, thereby solving the appearance problem of the fingerprint identification device under the screen .
  • the color filter layer is a white filter layer
  • the color filter layer here can be a transparent medium layer or other filter material that transmits visible light. No specific limitation is made.
  • the fingerprint identification unit 201 further includes: a third transparent medium layer 243, the third transparent medium layer 243 is disposed between the microlens 211 and the color filter layer 260.
  • the third transparent medium layer 243 is also a medium layer formed of an optical high transmittance material, which can be formed above the color filter layer 260 by a semiconductor spin coating process and a curing process, and the third transparent medium layer 243 can be formed by setting the third transparent medium layer.
  • the height of the dielectric layer 243 provides a certain focusing distance for the pixel units in the sensor chip.
  • the uppermost layer of the fingerprint identification unit 201 is a microlens 211, and its material is generally an optically transparent organic material, such as resin.
  • the microlens 211 may be a spherical microlens or an aspherical microlens.
  • FIG. 23 shows a schematic cross-sectional view of another fingerprint identification device 200 .
  • the bottom light blocking layer 221 and the middle light blocking layer 222 in addition to the microlens 211 and its corresponding four pixel units, it also includes: a protective layer 241, the protective layer 241 is located above the bottom light blocking layer 221 .
  • the fingerprint identification unit 201 further includes: an infrared filter layer 250 formed on the surface of the protective layer 241 for blocking infrared light signals.
  • the fingerprint identification unit 201 further includes: an adhesive layer 270 for connecting the intermediate light blocking layer 222 and the infrared filter layer 20 .
  • the adhesive layer 270 can be an organic material layer with high optical transmittance coated on the infrared filter layer 250, which can be realized by a semiconductor spin coating process and a curing process.
  • the adhesive layer 270 can be a flat transparent layer with a flat surface, so as to prevent the warpage of the infrared filter layer 250 formed by the multilayer organic material layer from affecting the flatness of the intermediate light blocking layer 222, thereby preventing the imaging effect from being affected.
  • a first transparent dielectric layer 244 is also formed above the intermediate light blocking layer 222 , and the first transparent dielectric layer 244 can be formed above the intermediate light blocking layer 222 by a semiconductor spin coating process and a curing process and fill the intermediate blocking layer 222 .
  • a semiconductor spin coating process and a curing process can be formed above the intermediate light blocking layer 222 by a semiconductor spin coating process and a curing process and fill the intermediate blocking layer 222 .
  • the fingerprint identification unit 201 further includes: a color filter layer 260 , the color filter layer 260 is disposed above the first transparent medium layer 244 and connects the first transparent medium layer 244 and the microlens 211 .
  • the color filter layer 260 is used to pass the light signal of the target wavelength band, and cut off the light signals of other non-target wavelength bands except the color light signal of the target wavelength band.
  • the color filter layer includes, but is not limited to, a red filter layer, a blue filter layer, a green filter layer or a white filter layer for transmitting red light signals, blue light signals, green light signals or white light Signal.
  • the protective layer 241 for the related technical solutions of the protective layer 241 , the bottom light blocking layer 221 , the intermediate light blocking layer 222 , the infrared filter layer 250 , and the color filter layer 260 in the embodiments of the present application, reference may be made to the relevant description in FIG. 22 above , and will not be repeated here.
  • Tables 1 and 2 show the numerical values of the parameters and the numerical values of the constraints in the fingerprint identification devices of several specific embodiments, wherein , the unit of each parameter in Table 1 is micrometer ( ⁇ m), and the unit of Pb parameter in Table 2 is ⁇ m.
  • Example 1 Example 2
  • Example 3 Example 4
  • Example 5 Example 6
  • Example 7 Pa 10.50 14.00 11.50 10.00 10.00 12.50 7.50 P b 21.00 28.00 23.00 20.00 20.00 25.00 15.00 CA 16.15 21.85 18.50 19.00 19.50 23.50 14.50 MLH 4.20 5.80 4.80 5.00 6.10 8.90 3.00 ROC 9.86 13.19 11.31 11.53 10.84 12.21 10.26 Z1 23.30 27.57 20.93 22.64 21.91 24.06 18.23 S1 8.20 9.62 7.51 7.60 6.05 10.08 5.09 D1 2.38 2.70 2.18 2.40 2.00 2.70 1.84 Z2 15.25 16.82 17.54 18.89 18.37 19.85 15.11 D2 13.30 15.88 18.10 18.43 16.02 25.05 12.48
  • Table 1 correspond to the fingerprint identification unit 201 and the fingerprint identification device 200 shown in FIG. 3 and FIG. 21 .
  • Table 2 exemplarily presents the calculated values of different constraints in various embodiments.
  • the parameters in the fingerprint identification device can also be designed by using the constraint values involved in Table 2, instead of being limited to the specific parameters listed in each embodiment in Table 1.
  • the embodiments of the present application are not limited to the above specific values, and those skilled in the art can determine the specific values of each parameter according to actual optical path design requirements.
  • the above parameters can be accurate to three or four digits after the decimal point.
  • FIG. 24 shows a graph of the contrast and brightness of the image collected by the fingerprint identification device 200 as a function of the shape of the openings of the intermediate light blocking layer 222 .
  • the image contrast and image brightness corresponding to the shape of the openings of the intermediate light blocking layer 222 are shown in Table 3.
  • FIG. 25 shows a schematic diagram of the image captured under the above four shapes of the openings of the intermediate light blocking layer. It is obvious from Fig. 24 and Fig. 25 that in the case of the same contrast, the image brightness decreases sequentially from a large circular through hole to an independent small hole. In the case of the same brightness, the image contrast increases sequentially from the large circular through hole to the independent small hole. However, all four aperture shapes can obtain relatively clear images.
  • an embodiment of the present application further provides an electronic device 500, which may include a display screen 510 and the fingerprint identification device 520 of the above-mentioned embodiment of the present application, wherein the fingerprint identification device is disposed below the display screen , in order to realize the optical fingerprint recognition under the screen.
  • the electronic device 500 can be any electronic device with a display screen.
  • the display screen 510 may adopt 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.
  • 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 fingerprint identification device 500 may also use a built-in light source or an external light source to provide an optical signal for fingerprint detection.
  • the fingerprint identification device 500 can be applied to a non-self-luminous display screen, such as a liquid crystal display screen or other passive light-emitting display screens.
  • the disclosed systems and apparatuses 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 indirect coupling or communication connection through some interfaces, devices or units, and may also be electrical, mechanical or other forms of connection.
  • 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 solutions of the embodiments of the present application.
  • 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 above-mentioned integrated units may be implemented in the form of hardware, or may be implemented in the form of software functional units.
  • the integrated unit if implemented in the form of a software functional unit and sold or used as an independent product, may be stored in a computer-readable storage medium.
  • the technical solutions of the present application are essentially or part of contributions to the prior art, or all or part of the technical solutions can be embodied in the form of software products, 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

本申请实施例公开了一种指纹识别装置和电子设备，该指纹识别装置包括呈阵列分布的多个指纹识别单元，多个指纹识别单元中的每个指纹识别单元包括：多个像素单元；微透镜，设置在该多个像素单元的上方；多层阻光层，设置在该微透镜和该多个像素单元之间，该多层阻光层中每一层阻光层中均设置有与该多个像素单元对应的通光小孔，以形成与该多个像素单元一一对应的多个导光通道；该多层阻光层包括底层阻光层和中间阻光层，该中间阻光层包括除该底层阻光层之外的阻光层，由该中间阻光层中与该多个像素单元对应的通光小孔形成的通光区域的通光口径D2与该微透镜的最大口径CA满足0.3≤D2/CA≤1.3，D2为该中间阻光层所在的平面上，该通光区域中最远的两点之间的距离。

Description

指纹识别装置和电子设备 技术领域
本申请实施例涉及指纹识别领域，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
由于未来手持电子产品日益小型化，目前镜头式的屏下光学指纹产品的尺寸难以适应这种趋势，急需向着厚度更薄、体积更小、集成化程度更高的方向发展。而当前存在的小型化方案中，利用准直孔成像的图像对比度与准直孔的深度有关，需要比较大的深度才能实现较高的成像质量，同时这种方案的光线利用率较低。利用微透镜聚焦的方案，受限于工艺和透镜面形，虽然光线利用率较高，但信号容易混叠，造成信号对比度偏低，指纹的成像质量不高。
因此，如何在实现光学指纹识别装置轻薄化的同时，兼顾提高指纹成像质量，是一项亟待解决的技术问题。
发明内容
本申请实施例提供一种指纹识别装置和电子设备，在实现指纹识别装置轻薄化的同时，兼顾提高指纹成像质量。
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呈阵列分布的多个指纹识别单元，该多个指纹识别单元中的每个指纹识别单元包括：多个像素单元；微透镜，设置在该多个像素单元的上方；多层阻光层，设置在该微透镜和该多个像素单元之间，该多层阻光层中每一层阻光层中均设置有与该多个像素单元对应的通光小孔，以形成与该多个像素单元一一对应的多个导光通道；其中，该多个像素单元分别用于接收从该显示屏上方的手指反射或散射返回的，通过该微透镜会聚后，再经由该多个导光通道传输的多个指纹光信号，该多个指纹光信号用于检测该手指的指纹信息以进行指纹识别；其中，该多层阻光层包括底层阻光层和中间阻光层，该中间阻光层包括除该底层阻光层之外的阻光层，由该中间阻光层中与该多个像素单元对应的通光小孔形成的通光区域的 通光口径D 2与该微透镜的最大口径CA满足0.3≤D 2/CA≤1.3，D2为该中间阻光层所在的平面上，该通光区域中最远的两点之间的距离。
本申请实施例的技术方案中，指纹识别装置中一个微透镜对应多个像素单元，可以提高指纹识别装置的进光量，减小曝光时间，增大视场。与此同时，通过单个微透镜与多像素单元搭配的成像光路可以对指纹的物方光束进行非正对光成像(即倾斜光成像)，能够提高干手指的识别效果，且能够扩大光学系统的物方数值孔径并缩短像素阵列的光路设计的厚度，最终能够有效降低指纹识别装置的厚度。
进一步地，在考虑制造工艺以及成本的基础上，通过约束指纹识别装置中的参数满足一定的条件，从而满足图像亮度和对比度的要求，具体地，可以约束中间阻光层中通光区域的通光口径D 2与微透镜的最大口径CA满足0.3≤D 2/CA≤1.3，以实施对指纹识别装置的光学系统的结构以及参数进行约束限制，在实现超薄指纹识别装置的同时，能够有效减少图像的混叠，成像具有较高的对比度以及较大的亮度，最终能够实现对各种目标较好的成像效果，进而提高识别准确度。
在一种可能的实现方式中，该中间阻光层的下表面至该微透镜的下表面之间的深度Z 2与该底层阻光层的下表面至该微透镜的下表面之间的深度Z 1满足0.1≤Z 2/Z 1≤0.9。
在约束0.3≤D 2/CA≤1.3的基础上，进一步约束0.1≤Z 2/Z 1≤0.9，即从中间阻光层的通光区域的尺寸以及中间阻光层在底层阻光层与微透镜之间的位置来约束中间阻光层，可以有效减少杂散光串扰，增加入射光线准直度，提高图像对比度，进而提高识别准确度。
在一种可能的实现方式中，若该中间阻光层的下表面至该微透镜的下表面之间的深度Z 2与该底层阻光层的下表面至该微透镜的下表面之间的深度Z 1满足0.1≤Z 2/Z 1≤0.5，该通光区域的通光口径D 2与该微透镜的最大口径CA满足0.5≤D 2/CA≤1，该通光区域的形状为一个圆形。
在一种可能的实现方式中，若该中间阻光层的下表面至该微透镜的下表面之间的深度Z 2与该底层阻光层的下表面至该微透镜的下表面之间的深度Z 1满足0.3≤Z 2/Z 1≤0.75，该通光区域的通光口径D 2与该微透镜的最大口径CA满足0.5≤D 2/CA≤0.8，该通光区域的形状为一个圆角矩形或一个花瓣形。
在一种可能的实现方式中，若该中间阻光层的下表面至该微透镜的下表 面之间的深度Z 2与该底层阻光层的下表面至该微透镜的下表面之间的深度Z 1满足0.65≤Z 2/Z 1≤0.9，该通光区域的通光口径D 2与该微透镜的最大口径CA满足0.8≤D 2/CA≤1.2，该中间阻光层中与该多个像素单元对应的通光小孔为一一对应的多个独立小孔。
通过约束0.3≤D 2/CA≤1.3以及0.1≤Z 2/Z 1≤0.9，并结合中间阻光层的开孔形状，可以在经济性和图像质量之间得到较好的平衡。
在一种可能的实现方式中，该通光区域的通光口径D 2与该微透镜的最大口径CA满足0.5≤D 2/CA≤1.2。
在一种可能的实现方式中，该中间阻光层的下表面至该微透镜的下表面之间的深度Z 2与该底层阻光层的下表面至该微透镜的下表面之间的深度Z 1满足0.5≤Z 2/Z 1≤0.9。
在一种可能的实现方式中，该底层阻光层中每个通光小孔的最大口径D 1与该微透镜的最大口径CA满足0.02≤D 1/CA≤0.4。
综合考虑成本、工艺、指纹成像性能等因素，在约束中间阻光层的参数范围的基础上，进一步约束底层阻光层中每个通光小孔的最大口径D 1与微透镜的最大口径CA满足0.02≤D 1/CA≤0.4，以实施对指纹识别装置的光学系统的结构以及参数进行约束限制，在实现超薄指纹识别装置的同时，能够进一步的降低杂散光对图像的影响，减少图像混叠，均衡图像的亮度以及对比度，实现包括指纹在内的各种目标较好的成像效果，从而进一步提高指纹识别装置的性能，提高指纹识别准确度。即能够进一步精准的满足提高图像亮度和对比度的要求，较大程度的优化图像质量。
在一种可能的实现方式中，该底层阻光层中每个通光小孔的最大口径D 1与该微透镜的最大口径CA满足0.08≤D 1/CA≤0.18。
在一种可能的实现方式中，该微透镜的曲率半径ROC与该底层阻光层的下表面至该微透镜的下表面之间的深度距离Z 1满足0.25≤ROC/Z 1≤0.75。
进一步约束微透镜的曲率半径ROC与该底层阻光层的下表面至微透镜的下表面之间的深度距离Z 1满足0.25≤ROC/Z 1≤0.75的条件，综合考虑了微透镜的焦点与底层阻光层的位置之间的比例关系，使得多个方向的目标指纹光信号中每个方向的目标指纹光信号被微透镜会聚后，均聚焦或者接近聚焦于底层阻光层中各通光小孔，以提高图像质量和识别成功率。
在一种可能的实现方式中，该微透镜的曲率半径ROC与该底层阻光层 的下表面至该微透镜的下表面之间的深度距离Z 1满足0.4≤ROC/Z 1≤0.6。
在一种可能的实现方式中，该多层阻光层中从下到上的第i层阻光层中每个通光小孔的位置满足0≤S i/Z 1≤1，其中，S i为该第i层阻光层中每个通光小孔的中心至该微透镜在该第i层阻光层上投影的中心的距离。
通过进一步约束多层阻光层中各通光小孔的位置，使得多个方向的目标指纹光信号更为准确的通过多层阻光层中每层阻光层的通光小孔传输至对应的像素单元，并且可以阻挡非目标方向的光信号，降低杂散光对于成像的影响，从而进一步的提高图像质量。
在一种可能的实现方式中，该第i层阻光层中每个通光小孔的位置满足0.2≤S i/Z 1≤0.5。
在一种可能的实现方式中，该底层阻光层中每个通光小孔为大小相同的圆形孔。
在一种可能的实现方式中，该指纹识别装置中微透镜的排列周期P b与该指纹识别装置中像素单元的排列周期P a满足1＜P b/P a≤4。
在一种可能的实现方式中，P b/P a＝2，一个该指纹识别单元包括4个像素单元。
在一种可能的实现方式中，P b/P a＝3，一个该指纹识别单元包括9个像素单元。
在一种可能的实现方式中，该指纹识别装置中微透镜的排列周期P b满足5μm≤P b≤40μm。
在一种可能的实现方式中，该指纹识别装置中微透镜的排列周期P b满足10μm≤P b≤30μm。
在一种可能的实现方式中，该底层阻光层为该多个像素单元表面的金属布线层。
在一种可能的实现方式中，该指纹识别单元还包括：保护层；该保护层设置于该底层阻光层上方，且与该底层阻光层、该多个像素单元一起集成在一起。
在一种可能的实现方式中，该多个导光通道在该中间阻光层中的通光小孔重合。
在一种可能的实现方式中，该通光区域的形状为圆形、圆角矩形或花瓣形。
在一种可能的实现方式中，该指纹识别单元还包括：红外滤光层，该红外滤光层为镀膜生长于该传感器芯片表面的滤光层，用于截止红外光。
在一种可能的实现方式中，该指纹识别单元还包括：粘附层，该粘附层为涂覆于该红外滤光层表面的平坦透明层，该中间阻光层设置于该粘附层上方。
在一种可能的实现方式中，该指纹识别单元还包括：第一透明介质层，设置于该中间阻光层上方并填充该中间阻光层中的通光小孔。
在一种可能的实现方式中，该指纹识别单元还包括：颜色滤光层，设置于该微透镜与该第一透明介质层之间，该颜色滤光层包括红色滤光层、蓝色滤光层、绿色滤光层或者白色滤光层。
在一种可能的实现方式中，该多个导光通道在该中间阻光层中的通光小孔相互独立。
在一种可能的实现方式中，该中间阻光层设置于该保护层的上表面。
在一种可能的实现方式中，该指纹识别单元还包括：第二透明介质层，设置于该中间阻光层上方并填充该中间阻光层中的通光小孔。
在一种可能的实现方式中，该指纹识别单元还包括：红外滤光层，该红外滤光层为镀膜生长于该第二透明介质层表面的滤光层，用于截止红外光。
在一种可能的实现方式中，该指纹识别单元还包括：颜色滤光层，设置于该红外滤光层上方，该颜色滤光层包括红色滤光层、蓝色滤光层、绿色滤光层或者白色滤光层。
在一种可能的实现方式中，该指纹识别单元还包括：第三透明介质层，设置于该微透镜与该颜色滤光层之间。
第二方面，提供一种电子设备，包括：显示屏；以及第一方面或者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。
在电子设备中设置上述指纹识别装置，通过设置指纹识别装置中的一个微透镜对应多个像素单元，可以提高指纹识别装置的进光量，减小曝光时间，增大视场。与此同时，通过单个微透镜与多像素单元搭配的成像光路可以对指纹的物方光束进行非正对光成像(即倾斜光成像)，能够提高干手指的识别效果，且能够扩大光学系统的物方数值孔径并缩短像素阵列的光路设计的厚度，最终能够有效降低指纹识别装置的厚度。进一步地，在考虑制造工艺 以及成本的基础上，通过约束指纹识别装置中的参数满足一定的条件，从而满足图像亮度和对比度的要求，具体地，可以约束中间阻光层中通光区域的通光口径D 2与微透镜的最大口径CA满足0.3≤D 2/CA≤1.3，以实施对指纹识别装置的光学系统的结构以及参数进行约束限制，在实现超薄指纹识别装置的同时，能够有效减少图像的混叠，成像具有较高的对比度以及较大的亮度，最终能够实现对各种目标较好的成像效果，进而提高识别准确度。通过提升指纹识别装置的指纹识别性能，从而提升该电子设备的指纹识别性能。
附图说明
图1和图2是一种指纹识别装置的示意性截面图和示意性俯视图。
图3至图5是根据本申请实施例的另一指纹识别装置的示意性截面图、示意性俯视图和示意性立体图。
图6至图8是根据本申请实施例的另一指纹识别装置的示意性截面图、示意性俯视图和示意性立体图。
图9是根据本申请实施例的一种指纹识别装置中像素阵列的排列示意图。
图10是理想情况下，中间阻光层中对应于一个指纹识别单元的多个像素单元的通光小孔的示意图。
图11是本申请实施例的一种指纹识别单元的示意性截面图。
图12是本申请实施例的另一种指纹识别单元的示意性截面图。
图13至图17是本申请实施例的中间阻光层的通光区域的示意图。
图18是本申请实施例的指纹识别装置采集的图像的衬度和亮度随D 2/CA变化的曲线。
图19是本申请实施例的三种D 2/CA约束条件下采集图像的示意图。
图20是本申请实施例的不同D 2/CA约束条件下的指纹识别装置的示意性截面图。
图21是本申请实施例的不同D 2/D 1约束条件下的指纹识别装置的示意性截面图。
图22示出了本申请实施例的一种指纹识别装置的示意性截面图。
图23示出了本申请实施例的另一种指纹识别装置的示意性截面图。
图24示出了指纹识别装置采集的图像的衬度和亮度随中间阻光层的通 光区域的形状变化的曲线。
图25示出了四种中间阻光层的通光区域的形状下采集图像的示意图。
图26示出了本申请实施例的一种电子设备的示意性框图。
具体实施方式
伴随时代的发展和科技的进步，电子产品屏幕的屏占比越来越高，全面屏已经成为众多电子产品的发展趋势。为适应这种全面屏的发展趋势，电子产品中的感光器件例如指纹识别、前置摄像头等也将被放置在屏幕之下。屏下指纹识别技术应用最多的是屏下光学指纹识别技术，由于屏下光学指纹器件的特殊性，要求带有指纹信号的光能够透过屏幕传递到下方的指纹传感器，进而得到指纹信号。
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、游戏设备等便携式或移动计算设备，以及电子数据库、汽车、银行自动柜员机(automated teller machine，ATM)等其他电子设备，但本申请实施例对此并不限定，本申请实施例可以应用在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。
通常，屏下指纹识别装置包括光学组件，该光学组件可以设置在光学指纹传感器的上方，其可以包括滤光层(Filter)、光路引导结构以及其他光学元件。
当前业界量产的屏下指纹识别装置中的光路引导结构主要有两种方案。一种是利用通孔小孔成像原理，小孔可以将手指反射的光信号引导至显示屏下方的传感器芯片，以进行指纹识别。理论上来说，小孔的孔径越小分辨率越高。但在实际的工业制造中，小孔的尺寸无法进一步缩小，从而限制其分辨率的提升。同时由于小孔只容许垂直方向的光信号进入，导致成像信号有限，无法提供足够的光信号到传感器芯片的采集区域。另一种方法利用光学 透镜进行成像，此种方式利用球面或非球面镜头聚光，以提升成像分辨率。另外，由于透镜具有汇聚光线的作用，因此，相比于小孔成像的方式，透镜成像能够引导较多的光信号到达传感器芯片。
随着电子设备朝着超薄化的方向发展，目前的指纹识别装置大多采用微透镜-小孔的结构，也就是说，指纹识别装置可以包括微透镜阵列和阻光层，微透镜阵列可以设置在阻光层的上方，阻光层设置有小孔阵列。微透镜阵列用于将手指反射的光信号汇聚至小孔阵列，小孔阵列可以将接收到的光信号引导至阻光层下方的指纹传感器芯片。指纹传感器芯片可以根据接收到的光信号进行指纹识别。
微透镜具有汇聚光线的作用，从而能够提高指纹传感器芯片生成的图像的分辨率。小孔阵列具有筛选光信号的作用，例如小孔阵列不允许大角度的干扰光信号通过，仅允许期望的特定角度范围内的光信号通过，以提高指纹识别效果。
应理解，在本申请实施例中，指纹识别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。另外，指纹识别装置中的光学指纹传感器也可以称为指纹传感器或者指纹传感器芯片。
还应理解，本申请实施例中的指纹识别装置也可以称为光学指纹装置、光学指纹识别模组、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1和图2示出了一种典型的指纹识别装置的示意性截面图和示意性俯视图。
如图1和图2所示，指纹识别装置100包括微透镜阵列110、至少一层阻光层120和像素阵列130。微透镜阵列110位于像素阵列130和至少一层阻光层120的正上方，且一个微透镜111对应一个像素单元131，即微透镜阵列110中的每一个微透镜111将接收到的光线通过至少一层阻光层120的小孔1201聚焦至同一微透镜111对应的像素单元131中。其中，每一个微透镜111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110入射的指纹光信号。
如图2所示，像素阵列130中的像素单元131按照周期性排列，且像素阵列130中的每一个像素单元131的感光区域1311均设置在同一个像素单 元的中心位置，以提高感光区域的占空比。
换言之，微透镜阵列110中的多个微透镜111和像素阵列130中的多个像素单元131一一对应，且像素阵列130中多个像素单元131的感光区域1311呈周期性排列且均匀分布。
但是，像素阵列130的感光区域会受到微透镜阵列110的尺寸的影响，且指纹识别装置100的厚度较大，进而增加了指纹识别装置100的光路的加工难度、周期以及成本。
在该指纹识别装置100中，由于多个微透镜相邻较近，光线可能从其他微透镜中入射到芯片表面，因此影响成像效果。且由于微透镜和像素单元是一一对应的，一个像素单元能够接收到的理论最大信号量，是当微透镜占满一个像素单元的面积后，接收的准直光的能量。这种接收方式，限制了图像信号量的进一步提升，在微弱光照下，信噪比较低，影响了图像质量。
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100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100对于干手指的指纹识别性能较差。
基于上述问题，本申请提出一种指纹识别装置200，采用一层或更多层设置有小孔阵列的阻光层与微透镜阵列相结合，且每一个微透镜对应多个像素单元。多个像素单元中每个像素单元都能收到整个微透镜会聚的倾斜准直光，但是对应一个微透镜的多个像素单元，接收的入射光倾斜方向不同。最终可以从图像芯片阵列中取出多张图像，每张都是由相同倾斜方向接收的像素单元构成的。这种接收方式，能够大幅提升图像的衬度和亮度，还可以实现扩大物方视场尺寸等其他应用方向。
图3至图5示出了该指纹识别装置200的示意性截面图、示意性俯视图和示意性立体图。
如图3至图5所示，该指纹识别装置200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200包括呈方形阵列分布的多个指纹识别单元201。如图3至5所示，在该指纹识别装置200中，每个指纹识别单元201包括：
多个像素单元；
微透镜211，设置在该多个像素单元的上方；
至少一层阻光层，设置在多个像素单元和微透镜211之间，至少一层阻光层中每一层阻光层均设置有与多个像素单元对应的通光小孔，以形成与该多个像素单元一一对应的多个导光通道；
其中，多个像素单元分别用于接收从显示屏上方的手指反射或散射返回的，通过微透镜211汇聚后，再经由多个传输通道传输的多个指纹光信号，该多个指纹光信号用于检测手指的指纹信息以进行指纹识别。
在具体实现中，至少一层阻光层中的每层挡光层对特定波段(比如可见光或者610nm以上波段)的光的透过率小于预设阈值(例如20％)，以避免相应的光通过。
应理解，指纹识别装置中的多个指纹识别单元中每个指纹识别单元201包括的微透镜形成微透镜阵列210。指纹识别装置中的多个指纹识别单元中每个指纹识别单元201所包括的多个像素单元形成像素阵列230。每个指纹识别单元201中的阻光层实际为局部阻光层。
为了方便描述，下文以指纹识别单元201为单位介绍本申请实施例中的指纹识别装置，指纹识别单元201中的局部阻光层简称为阻光层。
在一些实施例中，指纹识别单元201包括多层阻光层，底层阻光层221和中间阻光层222，其中，底层阻光层221为最靠近像素单元的阻光层，而中间阻光层222则为除底层阻光层之外的阻光层。
在一些实施例中，在指纹识别单元201中，一个微透镜对应4个像素单元。
例如，如图3至图5所示，其中，图3中的指纹识别单元201实际上为图5中的指纹识别单元201沿着第一像素单元231和第三像素单元233的中心的连线方向的截面图，图4为图5的俯视图。在指纹识别单元201中，第一微透镜211下方对应设置有第一像素单元231、第二像素单元232、第三像素单元233和第四像素单元234，该4个像素单元分别位于4个不同方向的导光通道的底部。
具体地，每个像素单元中均设置有感光区域(Active Area，AA)，用于分别接收经过四个导光通道的四个指纹光信号并转换为对应的电信号。该感光区域可以为像素单元中光电二极管所在的区域，即像素单元中接收光信号 的区域，像素单元中的其它区域可以用于设置像素单元中的其它电路以及用于像素间走线的排布。具体地，上述第一像素单元231中的第一感光区域2311，第二像素单元232中的第二感光区域2321，第三像素单元233中的第三感光区域2331以及第四像素单元234中的第四感光区域2341均设置在上述4个不同方向的导光通道的底部。
可选地，在一些实施方式中，例如，如图3至图5所示，第一微透镜211对应的4个导光通道在底层阻光层221以及中间阻光层222上均设置有4个通光小孔，每层阻光层上的4个通光小孔对应于4个像素单元。也就是说，4个导光通道分别在底层阻光层221和中间阻光层222中的通光小孔相互独立。例如，在图4中，底层阻光层221上设置有对应于第一像素单元231的通光小孔2211，中间阻光层222上设置有对应于第一像素单元231的通光小孔2221，该通光小孔2211和通光小孔2221均为对应于第一像素单元231的第一导光通道上的通光小孔，换言之，该通光小孔2211和通光小孔2221形成对应于第一像素单元231的第一导光通道。可选地，该通光小孔2211和通光小孔2221的中心可以在一条直线上，该直线的方向即为第一导光通道的方向。第一方向的倾斜光信号21通过第一微透镜211会聚后，通过第一导光通道至第一像素单元231中的第一感光区域2311，而其他方向的光信号(例如，图中虚线所示的光信号)则被阻挡在阻光层中，无法传输至像素单元。
其中，上述第一方向的倾斜光信号21可以为经过显示屏上方的手指反射或散射后，穿过显示屏，到达第一微透镜211的第一方向的指纹倾斜光信号，该第一方向的倾斜光信号21可以用于检测指纹信息。
类似地，第一微透镜211下方其它像素单元对应的通光小孔的设置可以参见上文第一像素单元对应的通光小孔的设置，其它像素单元同样可以接收其它方向的倾斜指纹光信号，该其它方向的倾斜指纹光信号经过第一微透镜211会聚后，经过通光小孔形成的导光通道后，传输至对应的像素单元。例如，图3中，第三方向的倾斜光信号23通过第一微透镜211会聚后，通过第三导光通道至第三像素单元233中的第一感光区域2311。
在另一些实施例中，每个微透镜对应的4个导光通道在底层阻光层221中设置有4个通光小孔，该4个通光小孔对应于4个像素单元，4个导光通道在中间阻光层222上的通光小孔重合，即在中间阻光层222中仅设置1个 通光小孔。
图6至图8示出了另一种指纹识别装置的示意性截面图、示意性俯视图和示意性立体图。图6中的指纹识别单元201实际上为图8中的指纹识别单元201沿着第一像素单元231和第三像素单元233的中心的连线方向的截面面图，图7为图8的俯视图。
在图6至图8中，底层阻光层221上设置有对应于第一像素单元231的通光小孔2211，中间阻光层222上设置有1个大的通光小孔2221，该通光小孔2221对应于4个像素单元。该通光小孔2211和通光小孔2221形成对应于第一像素单元231的第一导光通道。可选地，该通光小孔2211和通光小孔2221的中心可以在一条直线上，该直线的方向即为第一导光通道的方向。第一方向的倾斜光信号21通过第一微透镜211会聚后，通过第一导光通道至第一像素单元231中的第一感光区域2311，而其他方向的光信号(例如，图中虚线所示的光信号)则被阻挡在阻光层中，无法传输至像素单元。
类似地，其它像素单元对应的通光小孔的设置可以参见上文第一像素单元对应的通光小孔的设置，此处不再赘述。
在上述申请实施例中，指纹识别装置200中每个微透镜对应的4个像素单元均通过4个不同方向的导光通道接收4个不同方向的倾斜光信号。由此，指纹识别装置200中的像素阵列230，可以基于接收到的4个不同方向的光信号生成4幅指纹图像，进而得到一幅高分辨率的指纹图像，以提升指纹识别效果。
图9示出了一种像素阵列230的排列示意图，如图9所示，其中，“1”表示用于接收第一方向的倾斜光信号的像素单元，“2”表示用于接收第二方向的倾斜光信号的像素单元，“3”表示用于接收第三方向的倾斜光信号的像素单元，“4”表示用于接收第四方向的倾斜光信号的像素单元。也就是说，在像素阵列230中，所有的“1”表示的像素单元分别可以用于生成第一幅指纹图像，所有的“2”表示的像素单元分别可以用于生成第二幅指纹图像，所有的“3”表示的像素单元分别可以用于生成第三幅指纹图像，所有的“4”表示的像素单元分别可以用于生成第四幅指纹图像，即总共可以生成4幅指纹图像，这4幅指纹图像可以用于单独进行指纹识别，或者也可以合并成一幅高分辨率的指纹图像，进而提升指纹识别装置的识别效果。
进一步地，由于4幅指纹图像通过不同方向的倾斜光信号生成得到，因 此该4幅指纹图像对应着不同的物方成像区域，还可以实现扩大物方视场尺寸等其他应用方向。
通过该实施例的方案，通过光路的设计，单个微透镜对应的4个像素单元能同时接收4个方向的光信号，从而提高指纹识别装置的进光量，减小曝光时间，增大视场。与此同时，通过单个微透镜与多像素单元搭配的成像光路可以对指纹的物方光束进行非正对光成像(即倾斜光成像)，能够提高干手指的识别效果，且能够扩大光学系统的物方数值孔径并缩短像素阵列的光路设计的厚度，最终能够有效降低指纹识别装置的厚度。
理想情况下，如图10所示，4个像素单元在中间阻光层中对应的4个通光小孔(光阑小孔)相互重合(图中虚线所示)。对于中间阻光层来说，通光小孔面积增加会导致杂散光进入，准直度降低。但受限于工艺技术，成本较低的技术无法得到较高的图形精度。因此，本申请实施例提供了几种技术方案，可以在较为经济的条件下得到较高的中间阻光层的开孔形状精度以及较好的图像质量。
图11和图12分别示出了两种指纹识别单元201的示意性截面图，图13至图15为图11的示意性俯视图，图16为图12的示意性俯视图。
在图13中，4个导光通道在中间阻光层222中的通光小孔重合，且为一个圆形大通孔。
一个圆形大通孔的优势在于制造精度需求较低。可选地，中间阻光层的开孔可以采用光刻或镀膜等方法制作，由于圆形是简单图形，其无论采用正胶还是负胶曝光都可以以较低的光刻分辨率得到完整图形。
在图14中，4个导光通道在中间阻光层222中的通光小孔重合，且为一个圆角矩形通孔。
相较于圆形大通孔，圆角矩形通孔可以在工艺上基本没有提高难度的情况下，进一步地减小了杂散光漏光区域，无论是采用正胶、负胶还是镀膜均可以实现。
在图15中，4个导光通道在中间阻光层222中的通光小孔重合，且为一个花瓣形通孔，该花瓣形的瓣数为4，是由4个相互重叠的开孔构成的，或者说是由4个存在交集的开孔构成的，花瓣的形状就是4个开孔交叠在一起形成的，其形状酷似于花瓣。开孔的形状可以为圆形、椭圆形或者其他形状，可选地，若一个指纹识别单元包括9个像素单元，即9个导光通道，该花瓣 形的瓣数为9，是由9个相互重叠的通光小孔构成的，换句话说，该花瓣形的瓣数可以与一个指纹识别单元所包括的像素单元有关。图15中示出了4个圆形的开孔相互部分重叠/相交后形成的花瓣形通光小孔。
相较于圆角矩形通孔和圆形大通孔，花瓣形通孔的优势是进一步减小了不必要的漏光区域，能最大限度的提升入射光线准直度，增加了图像对比度，但其需要更高的光刻分辨率，若采用镀膜的方式进行制造则会增加成本。
在图16中，4个导光通道在中间阻光层222中的通光小孔相互独立。
该结构下中间阻光层的各小孔之间无交错，对提高入射光线准直度、改善强光串扰等都有明显作用，但其对工艺加工分辨率要求高，且对材料要求高，可能出现各小孔之间的薄壁断裂的情况。
为了便于描述，在本申请实施例中，可以将D2定义为中间阻光层222中与4个像素单元对应的通光小孔形成的通光区域的通光口径，其中，通光口径D2可以为中间阻光层所在的平面上，通光区域中最远的两点之间的距离，例如，D 2可以为如图13所示的中间阻光层222上的圆形直径，或者是如图14所示的中间阻光层222上的圆角矩形的对角线，或者是如图15所示的中间阻光层222上花瓣形中经过其中心的最大尺寸，或者还可以如图16所示的中间阻光层222上两个对角小孔之间的最远距离。
另外，还可以将CA定义为微透镜211的最大口径，例如，CA可以是微透镜211在水平面方向最大的剖面中的最大宽度。
可选地，微透镜211可以为球面透镜或者为非球面透镜，其上表面为球面或者为非球面，下表面为水平面，该微透镜211的最大口径CA可以为其下表面的最大宽度。
例如，在图11和图12中，微透镜211可以为球面透镜，其下表面为圆形水平面，该微透镜211的最大口径CA为圆形水平面的直径。
应理解，虽然本申请实施例仅示出了中间阻光层222的四种开孔形状，但本申请实施例应不限于此，中间阻光层222的通光区域的形状还可以为如图17所示的异形，即不规则形状，D2则定义为如图所示。
在本申请实施例中，该通光区域的通光口径D 2与微透镜211的最大口径CA满足0.3≤D 2/CA≤1.3。可以理解的是指纹识别装置包括多层中间阻光层时，可以是任一层中间阻光层满足D 2/CA的取值范围，以及其他与中间阻光层相关的参数范围。也可以是多层中间阻光层均满足相关参数范围。
图18示出了图像的衬度和亮度随着D 2/CA的曲线图。图19示出了三种D 2/CA约束条件下采集图像的示意图。可以理解的是，图像衬度表征的是图像中明暗程度的差异，也可以理解为图像的对比度。
如图18所示，随着D 2/CA的增大，图像衬度降低，但图像亮度则增大，进一步通过图19可以看出，在D 2/CA≈0.7处，图像衬度和图像亮度重合且均较高，图像成像效果最优，D 2/CA较大或者较小，图像过亮或者过暗，图像的对比度较差，图像成像效果较差。
基于本申请实施例的技术方案，在考虑制造工艺以及成本的基础上，通过约束指纹识别装置中的参数满足一定的条件，从而满足图像亮度和对比度的要求，具体地，可以约束中间阻光层中通光区域的通光口径D 2与微透镜的最大口径CA满足0.3≤D 2/CA≤1.3，若D 2/CA过小时，则该中间阻光层中通光区域的进光量较少，可能会导致图像变暗，噪声提升；若D 2/CA过大，则可能会导致杂散光进入，从而影响图像清晰度。若D 2/CA在本申请所约束的范围内时，在成像时能够有效减少图像的混叠，成像具有较高的对比度以及较大的亮度，最终能够实现对各种目标较好的成像效果，进而提高识别准确度。
在本申请实施例中，Z i可以定义为从下到上的第i层阻光层的下表面至微透镜211的下表面之间的深度。例如，在图11和图12中，Z 1定义为底层阻光层221的下表面至微透镜211的下表面之间的深度，Z 2定义为中间阻光层222的下表面至微透镜211的下表面之间的深度。
可选地，还可以约束中间阻光层222的下表面至微透镜211的下表面之间的深度Z 2与底层阻光层221的下表面至微透镜211的下表面之间的深度Z 1满足0.1≤Z 2/Z 1≤0.9。
无论Z 2/Z 1过大或过小，都会导致较多杂散光进入，通过约束0.1≤Z 2/Z 1≤0.9，可以有效减少杂散光串扰。
在约束0.3≤D 2/CA≤1.3的基础上，进一步约束0.1≤Z 2/Z 1≤0.9，即从中间阻光层的通光区域的尺寸以及中间阻光层在底层阻光层与微透镜之间的位置来约束中间阻光层，可以有效减少杂散光串扰，增加入射光线准直度，提高图像对比度，进而提高识别准确度。
进一步地，通过约束中间阻光层的参数范围，并结合中间阻光层的开孔形状，可以在经济性和图像质量之间得到较好的平衡。
例如，当0.1≤Z 2/Z 1≤0.5时，由于中间阻光层222距离微透镜211较近，在理想情况下，各像素单元在中间阻光层222中所需的通光小孔相对于微透镜211的偏移量较少，此时可以进一步约束0.5≤D 2/CA≤1，就可以采用工艺难度较低的圆形大通孔来实现，较好地限制了杂散光入射，从而在较为经济的条件下保证图像亮度与对比度。
再例如，当0.3≤Z 2/Z 1≤0.75时，由于中间阻光层222与微透镜211的距离变远，在理想情况下，各像素单元在中间阻光层222中所需的通光小孔相对于微透镜211的偏移量逐渐增大，此时可以进一步约束0.5≤D 2/CA≤0.8，就可以采用工艺难度适中的圆角矩形通孔或者花瓣形通孔来实现，可以在不减小通光小孔的前提下尽可能减少杂散光入射，获取较好的图像亮度与对比度。
再例如，当0.65≤Z 2/Z 1≤0.9时，由于中间阻光层222与微透镜211的距离较远，在理想情况下，各像素单元在中间阻光层222中所需的通光小孔相较于微透镜211的偏移量较大，此时，可以进一步约束0.8≤D 2/CA≤1.2，就可以采用4个独立小孔来更好地减少杂散光入射，从而获得较好的图像亮度和对比度。但受限于工艺难度，此时也可以采用单一的圆角矩形通孔和花瓣形通孔。
可以理解的是，在上文中以指纹识别单元201中，一个微透镜对应4个像素单元为例，说明了指纹识别装置的结构以及指纹成像原理，可选地，在指纹识别单元201中，一个微透镜还可以对应2个、3个、或者4个以上的像素单元，例如9个，16个等的像素单元，本申请实施例对指纹识别单元中像素单元的数量不做限定。
可选地，考虑工艺以及成本问题，在本申请实施例中，每个指纹识别单元201中像素单元的数量可以为A×A，其中，1＜A≤4，且A为正整数，优选地，A＝2或者3。
在一些实施例中，A＝3，即每个指纹识别单元中包括9个像素单元，也就是说，一个微透镜对应9个像素单元，底层阻光层也可以包括9个通光小孔，其中，底层阻光层中的一个通光小孔对应一个像素单元。可选地，中间阻光层只包括一个通光小孔，即一个微透镜对应中间阻光层的一个通光小孔，该中间阻光层的一个通光小孔对应底层阻光层的9个通光小孔，底层阻光层的9个通光小孔与9个像素单元一一对应。可选地，中间阻光层包括9 个通光小孔，即一个微透镜对应中间阻光层的9个通光小孔，该中间阻光层的9个通光小孔与底层阻光层的9个通光小孔一一对应，该底层阻光层的9个通光小孔与9个像素单元一一对应。
在一些实施例中，A＝4，即每个指纹识别单元中包括16个像素单元，也就是说，一个微透镜对应16个像素单元，底层阻光层也可以包括16个通光小孔，其中，底层阻光层中的一个通光小孔对应一个像素单元。可选地，中间阻光层只包括一个通光小孔，即一个微透镜对应中间阻光层的一个通光小孔，该中间阻光层的一个通光小孔对应底层阻光层的16个通光小孔，底层阻光层的16个通光小孔与16个像素单元一一对应。可选地，中间阻光层包括16个通光小孔，即一个微透镜对应中间阻光层的16个通光小孔，该中间阻光层的16个通光小孔与底层阻光层的16个通光小孔一一对应，该底层阻光层的16个通光小孔与16个像素单元一一对应。
当中间阻光层中只包括一个通光小孔时，通光小孔的形状可以为圆形、圆角矩形或花瓣形，具体可以参照前述相关内容，这里不再赘述。
可选地，在本申请实施例中，A＝P b/P a，其中，P b定义为指纹识别装置中多个微透镜的排列周期，P a定义为指纹识别装置中多个像素单元的排列周期。
例如，多个指纹识别单元201呈阵列排列后，其中的多个微透镜形成微透镜阵列，其中多个像素单元形成像素阵列，在水平面上，多个微透镜在X方向和Y方向上的排列周期均为P b，多个像素单元在X方向和Y方向上的排列周期均为P a，在本申请中，水平面平行于显示屏所在平面，垂直面垂直于显示屏所在平面。
综合考虑图像空间采样率以及工艺成本，在一些实施方式中5μm≤P b≤40μm，优选地，10μm≤P b≤30μm。
在本申请实施例中，D 1定义为底层阻光层中每个通光小孔的最大口径。
例如，底层阻光层中的多个通光小孔为圆形小孔，则D 1表示通光小孔的直径。
再例如，底层阻光层中的多个通光小孔为圆角矩形小孔或者矩形小孔，则D 1表示通光小孔对角之间的距离。
可选地，底层阻光层中的多个通光小孔的形状可以相同或不相同。例如，底层阻光层中的多个通光小孔的形状一致，即该多个通光小孔可以都是圆形 小孔、圆角矩形小孔或矩形小孔。再例如，底层阻光层中的多个通光小孔的形状不一致，即该多个通光小孔可以包括圆形小孔、圆角矩形小孔和矩形小孔中的至少两种。可选的，当指纹识别单元201中的微透镜211对应4个像素单元时，微透镜211对应底层挡光层221的4个通光小孔，4个通光小孔中可以包括3个圆形通光小孔和1个矩形小孔，或者4个通光小孔中可以包括3个圆形通光小孔和1个圆角矩形小孔，4个通光小孔中可以包括2个圆形通光小孔和1个矩形小孔和一个圆角矩形小孔等等，4个通光小孔的形状可以任意组合，但考虑到工艺复杂性，工序步骤，优选的通光小孔的形状保持一致。
可选地，底层阻光层中的多个通光小孔的大小可以相同或不相同。例如，该多个通光小孔中至少两个通光小孔的口径不同。再例如，该多个通光小孔中每个通光小孔的口径相同。
优选地，底层阻光层的多个通光小孔为口径一致的圆形小孔。
在本申请实施例中，底层阻光层中的通光小孔采用圆形通光小孔、圆角矩形小孔或者矩形小孔，具有良好的对称性，对各个方向上的光信号具有对称的通光性能，从而能够提高图像在各个方向上的均衡性，从而提高图像质量。
可选地，在本申请实施例中，可以约束底层阻光层221中每个通光小孔的最大口径D 1与微透镜的最大口径CA满足0.02≤D 1/CA≤0.4。
通过约束底层阻光层中每个通光小孔的最大口径D 1与微透镜的最大口径CA满足0.02≤D 1/CA≤0.4，综合考虑了微透镜的受光面积与通光小孔大小之间的比例关系，在该比例关系小于等于0.4时，当前微透镜下方的底层阻光层中每个通光小孔能够良好的遮挡相邻微透镜传导的杂散光，减少图像的混叠，从而提高成像的对比度，或者说提高图像的衬度，在该比例关系大于等于0.02时，保证底层阻光层中每个通光小孔能够通过足够的光信号，以保证成像的亮度，因此，采用本申请实施例的方案，能够兼顾图像亮度以及图像对比度，从而提高图像质量和识别成功率。
一般来讲，若需要提高图像的亮度以及图像对比度，则可以增加一个指纹识别单元中微透镜对应的像素单元数量，则能够更为充分的利用微透镜会聚的光信号，且提高图像的空间采样率，从而提高图像的亮度和对比度，但采用该方式会造成制造工艺难度上升且成本增高。因此，采用本申请实施例 的技术方案，在考虑制造工艺以及成本的基础上，通过约束指纹识别装置中的参数满足一定的条件，满足图像亮度和对比度的要求。
在一些实施方式中，0.08≤D 1/CA≤0.18。优选地，0.12≤D 1/CA≤0.14，例如：D 1/CA＝0.12，0.13或者0.14，或者D 1/CA还可以为0.12至0.14之间任意的数值，本申请实施例对此不做具体限定。
具体地，在满足0.08≤D 1/CA≤0.18的基础上，若满足0.5≤D 2/CA≤1.2，则图像亮度和清晰度则会达到一定的平衡。如图20所示，D 2/CA过小，则进光量降低，图像会变暗且噪声会提升；D 2/CA过大，则会导致杂散光(虚线表示)进入，从而影响图像清晰度。
在一些实施例中，微透镜211的曲率半径ROC与该底层阻光层221的下表面至微透镜211的下表面之间的深度距离Z 1满足0.25≤ROC/Z 1≤0.75。
当多个方向的目标指纹光信号中每个方向的目标指纹光信号被微透镜会聚后，均聚焦于底层阻光层中各通光小孔时，此时成像效果最优，在兼顾图像亮度的同时能够提高图像对比度。因此，通过本申请实施例的技术方案，约束微透镜的曲率半径ROC与该底层阻光层的下表面至微透镜的下表面之间的深度距离Z 1满足0.25≤ROC/Z 1≤0.75，综合考虑了微透镜的焦点与底层阻光层的位置之间的比例关系，使得底层阻光层中各通光小孔满足或者接近上述条件，以提高图像质量和识别成功率。
可选地，若微透镜为球面透镜，如图10和图11所示，则该微透镜的曲率半径ROC可以通过如下公式计算得到：
Figure PCTCN2021085455-appb-000001
其中，MLH为微透镜的高度，即微透镜的顶点到其下表面的高度，CA为微透镜的最大口径。
当然，非球面透镜的曲率半径也有其计算方式，具体的计算方式可以参见相关技术中的计算方法，此处不做具体论述。
在一些实施方式中，0.4≤ROC/Z 1≤0.6。优选地，0.47≤ROC/Z 1≤0.49，例如：ROC/Z 1＝0.47，0.48或者0.49，或者ROC/Z 1还可以为0.47至0.49之间任意的数值，本申请实施例对此不做具体限定。
具体地，在满足0.4≤ROC/Z 1≤0.6的基础上，若满足0.5≤Z 2/Z 1≤0.9，则可减少杂散光串扰。如图21所示，Z 2/Z 1过大或过小，都会增加杂散光的串 扰。
可选地，在本申请实施例中，每层阻光层中各通光小孔的位置可以约束为：0≤S i/Z 1≤1，优选地，在一些实施方式中，0.2≤S i/Z 1≤0.5，其中，S i表示指纹识别单元中的第i层阻光层中的各通光小孔距离微透镜在该第i层阻光层上投影的中心的偏移量。类似地，第i层阻光层的下表面至微透镜的下表面之间的深度距离可以表示为Z i。
应理解，该第i层阻光层中各通光小孔的中心距离微透镜在该第i层阻光层上投影的中心的偏移量S i可以相同，也可以不同，本申请实施例对此不做具体限定。
通过约束多层阻光层中各通光小孔的位置，使得多个方向的目标指纹光信号更为准确的通过多层阻光层中每层阻光层的通光小孔传输至对应的像素单元，并且可以阻挡非目标方向的光信号，降低杂散光对于成像的影响，从而进一步的提高图像质量。
此处需要说明的是，在其它一些实施方式中，也可以调整该S 1/Z 1的约束范围，然后根据该S 1/Z 1的约束范围，调整上述ROC/Z 1的约束范围，从而通过调整底层阻光层中通光小孔的位置，调整需求的目标指纹光信号的角度，然后再调整微透镜的曲率半径以及底层阻光层的下表面至微透镜的下表面之间的深度距离，以使得本申请实施例中的指纹识别装置在满足良好的成像条件的同时，可以接收各种角度的倾斜光信号，适用于更广泛的应用场景。
可选地，在本申请实施例中，可以约束微透镜的曲率半径ROC与该底层阻光层的下表面至微透镜的下表面之间的深度距离Z 1满足0.25≤ROC/Z 1≤0.75，且底层阻光层中每个通光小孔的最大口径D 1与微透镜的最大口径CA满足0.02≤D 1/CA≤0.4，综合两种约束条件，可以进一步精准的满足提高图像亮度和对比度的要求，较大程度的优化图像质量。
可选地，在本申请实施例中，还可以同时约束底层阻光层的参数满足一定条件以及中间阻光层的参数满足一定条件，从而可以进一步精准的满足提高图像亮度和对比度的要求，较大程度的优化图像质量。
在图3至图5所示的指纹识别装置的基础上，图22示出了另一种指纹识别装置200的截面示意图。
如图22所示，在指纹识别单元201中，除了微透镜211及其对应的4个像素单元，底层阻光层221和中间阻光层222之外，还包括：保护层241， 该保护层241位于底层阻光层221上方。
可选地，在本申请实施例中，底层阻光层221可以与像素单元集成在一起，也就是说底层阻光层和像素单元可以集成在指纹识别装置的中的指纹传感器芯片的内部，为指纹传感器芯片内部部件，可选地，该底层阻光层221可以是传感器芯片中位于像素单元上方的金属线路层，即底层阻光层可以是像素单元的金属线路层，用于传递电信号，或者该底层阻光层221也可以为其它可见光透过率低的材料层。
上述保护层241可以同样为传感器芯片中的叠层结构，其形成于传感器芯片的表面，用于保护传感器芯片防止受到外界水汽与例子的污染，导致传感器性能失效。可选地，该保护层241包括但不限于是硅的氧化物和/或硅的氮化物。
可以理解的是，该保护层241同样为透明材料层，对于光信号具有高透过率，通过设置该保护层211的高度，可以为传感器芯片中的像素单元提供一定的聚焦距离。
如图23所示，中间阻光层222设置于上述传感器芯片的上表面，即设置于上述保护层241的上表面。这样设置可以减小底层阻光层221和中间阻光层222之间的距离，提高两层阻光层中形成的导光通道的导光性能。
在具体实现上，该中间阻光层222可以是黑色高分子吸光材料，以吸收环境中的大部分光信号。
进一步地，指纹识别单元201还包括：第二透明介质层242，该第二透明介质层242设置于上述中间阻光层222上方并填充该中间阻光层222中的通光小孔。该第二透明介质层242同样为光学高透过率材料形成的介质层。
可选地，该第二透明介质层242可以通过半导体旋涂工艺与固化工艺形成于中间阻光层222上方并填充该中间阻光层222中的通光小孔，通过设置该第二透明介质层242的高度，也可以为传感器芯片中的像素单元提供一定的聚焦距离。
继续参见图23，指纹识别单元201还包括：红外滤光层250，用于截止红外光以及部分红光，防止该红外光以及部分红光进入到像素单元中，影响成像效果。
例如，在强光情况下，环境中红外光较强，该较强的红外光若进入像素单元中，容易造成像素单元的信号饱和，且红外光易穿透手指，形成手指的 透射光，该部分透射光会影响正常指纹识别过程中，手指反射光的成像，综合两方面原因，红外光对指纹成像影响较大，需要通过红外滤光层进行截止滤除。
在一些实施方式中，该红外滤光层250包括多层无机材料层，该多层无机材料层可以采用镀膜工艺在第二透明介质层242上镀膜形成，该镀膜工艺包括但不限于是物理气相沉积(physical vapor deposition，PVD)镀膜方法。该多层无机材料层可以为二氧化钛/二氧化硅(TiO 2/SiO 2)交替生长的多层无机材料层，或者为五氧化二铌/二氧化硅(Nb 2O 5/SiO 2)交替生长的多层无机材料层，或者还可以为其它用于截止红外光信号的有机或者无机材料，本申请实施例对此不做限定。
如图23所示，该指纹识别单元201还包括：颜色滤光层260，该颜色滤光层260设置于上述红外滤光层250上方，用于通过目标波段的光信号，并截止除该目标波段的彩色光信号以外的其它非目标波段的光信号，该颜色滤光层可以通过半导体光刻工艺实现。
可选地，该颜色滤光层包括但不限于是红色滤光层、蓝色滤光层、绿色滤光层或者白色滤光层，用于透过红光信号、蓝光信号、绿光信号或者白光信号。
一方面，若颜色滤光层为彩色滤光层，透过彩色光信号，该指纹识别单元201中的像素单元接收的为彩色光信号，可以用于进行指纹防伪来判断真假手指。若颜色滤光层为白色滤光层，透过白光信号，则该指纹识别单元201中的像素单元接收的为白光信号，可以用于进行指纹图像生成以进行指纹识别。则本申请实施例提供的指纹识别装置可以在指纹识别的基础上进一步进行指纹防伪判断，提高指纹识别的成功率。
另一方面，该颜色滤光层可以用于对其下方红外滤光层反射的光信号进行吸收，防止反射的光信号透过显示屏被人眼接收，从而解决屏下指纹识别装置的外观问题。
可以理解的是，若颜色滤光层为白色滤光层，则此处的颜色滤光层可以为透明介质层或者其它透过可见光的滤光材料，本申请实施例对颜色滤光层的结构不做具体限定。
继续参见图23，在颜色滤光层260上方，该指纹识别单元201还包括：第三透明介质层243，该第三透明介质层243设置于微透镜211与上述颜色 滤光层260之间。
可选地，该第三透明介质层243同样为光学高透过率材料形成的介质层，其可以通过半导体旋涂工艺与固化工艺形成于颜色滤光层260上方，并通过设置该第三透明介质层243的高度，为传感器芯片中的像素单元提供一定的聚焦距离。
指纹识别单元201的最上层为微透镜211，其材料一般为光学透明有机材料，例如树脂等，其可以通过半导体光刻工艺设计微透镜211的大小和形状，并通过热回流工艺方式成形。该微透镜211可以为球面微透镜或者也可以为非球面微透镜。
在图6至图8所示的指纹识别装置的基础上，图23示出了另一种指纹识别装置200的截面示意图。
如图23所示，在该指纹识别单元201中，除了微透镜211及其对应的4个像素单元，底层阻光层221和中间阻光层222以外，还包括：保护层241，该保护层241位于底层阻光层221上方。
可选地，如图23所示，该指纹识别单元201还包括：红外滤光层250，该红外滤光层250形成于保护层241的表面，用于截止红外光信号。
进一步地，在该红外滤光层250上方，该指纹识别单元201还包括：粘附层270，用于连接中间阻光层222和红外滤光层20。
可选地，该粘附层270可以为涂覆于红外滤光层250上方的光学高透过率有机材料层，其可以通过半导体旋涂工艺和固化工艺实现。该粘附层270可以为表面平坦的平坦透明层，防止多层有机材料层形成的红外滤光层250产生的翘曲影响中间阻光层222的平坦度，从而防止影响成像效果。
继续参见图23，中间阻光层222上方还形成有第一透明介质层244，该第一透明介质层244可以通过半导体旋涂工艺与固化工艺形成于中间阻光层222上方并填充该中间阻光层222中的通光小孔，通过设置该第一透明介质层244的高度，可以为传感器芯片中的像素单元提供一定的聚焦距离。
可选地，该指纹识别单元201还包括：颜色滤光层260，该颜色滤光层260设置于上述第一透明介质层244上方，连接第一透明介质层244和微透镜211。该颜色滤光层260用于通过目标波段的光信号，并截止除该目标波段的彩色光信号以外的其它非目标波段的光信号。同样的，该颜色滤光层包括但不限于是红色滤光层、蓝色滤光层、绿色滤光层或者白色滤光层，用于 透过红光信号、蓝光信号、绿光信号或者白光信号。
具体地，本申请实施例中的保护层241、底层阻光层221、中间阻光层222、红外滤光层250、颜色滤光层260的相关技术方案可以参见上文图22中的相关描述，此处不再赘述。
以上描述了本申请提出的各种指纹识别装置的结构以及其中参数的约束条件，下述表1和表2示出了几种具体实施例的指纹识别装置中参数的数值以及约束条件数值，其中，表1中各参数的单位均为微米(μm)，且表2中P b参数的单位为μm。
表1
参数 例一 例二 例三 例四 例五 例六 例七
P a 10.50 14.00 11.50 10.00 10.00 12.50 7.50
P b 21.00 28.00 23.00 20.00 20.00 25.00 15.00
CA 16.15 21.85 18.50 19.00 19.50 23.50 14.50
MLH 4.20 5.80 4.80 5.00 6.10 8.90 3.00
ROC 9.86 13.19 11.31 11.53 10.84 12.21 10.26
Z1 23.30 27.57 20.93 22.64 21.91 24.06 18.23
S1 8.20 9.62 7.51 7.60 6.05 10.08 5.09
D1 2.38 2.70 2.18 2.40 2.00 2.70 1.84
Z2 15.25 16.82 17.54 18.89 18.37 19.85 15.11
D2 13.30 15.88 18.10 18.43 16.02 25.05 12.48
其中，表1中的实施例对应于图3和图21所示的指纹识别单元201以及指纹识别装置200。
基于表1的参数的取值，下述表2示例性给出了各种实施例中不同约束条件的计算值。
表2
Figure PCTCN2021085455-appb-000002
Figure PCTCN2021085455-appb-000003
如表2所示，也可以利用表2中涉及的约束值来设计指纹识别装置中的参数，而不局限于表1中各实施例列举的具体参数。
需要说明的是，本申请实施例并不局限于上述具体数值，本领域技术人员可以根据实际的光路设计需求确定各个参数的具体数值。例如，上述参数可以精确到小数点后的三位数或四位数。
基于表1和表2中的实施例二，图24示出了指纹识别装置200采集的图像的衬度和亮度随中间阻光层222的开孔形状变化的曲线图。具体地，中间阻光层222的开孔形状对应的图像衬度和图像亮度如表3所示。
表3
  图像衬度 图像亮度
圆形大通孔 84.70％ 121.11％
圆角矩形通孔 88.16％ 116.31％
花瓣形通孔 100％ 100％
独立小孔 104.85％ 90.24％
图25示出了中间阻光层的开孔为上述四种形状下采集图像的示意图。从图24和图25中明显看出，在同一衬度的情况下，从圆形大通孔变化到独立小孔，图像亮度依次降低。而在同一亮度的情况下，从圆形大通孔变化到独立小孔，图像衬度依次增加。但四种开孔形状均可以获得较为清晰的图像。
以上结合附图详细描述了本申请的优选实施方式，但是，本申请并不限于上述实施方式中的具体细节，在本申请的技术构思范围内，可以对本申请的技术方案进行多种简单变型，这些简单变型均属于本申请的保护范围。
例如，在上述具体实施方式中所描述的各个具体技术特征，在不矛盾的情况下，可以通过任何合适的方式进行组合，为了避免不必要的重复，本申请对各种可能的组合方式不再另行说明。
又例如，本申请的各种不同的实施方式之间也可以进行任意组合，只要其不违背本申请的思想，其同样应当视为本申请所公开的内容。
应理解，在本申请的各种方法实施例中，上述各过程的序号的大小并不意味着执行顺序的先后，各过程的执行顺序应以其功能和内在逻辑确定，而 不应对本申请实施例的实施过程构成任何限定。
如图26所示，本申请实施例还提供了一种电子设备500，该电子设备可以包括显示屏510以及上述本申请实施例的指纹识别装置520，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500可以为任何具有显示屏的电子设备。
作为一种可选的实施例，显示屏510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，指纹识别装置520可以利用OLED显示屏510位于指纹检测区域的显示单元(即OLED光源)来作为光学指纹检测的激励光源。
在其他实施例中，指纹识别装置500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，该指纹识别装置500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。
关于指纹识别装置在电子设备中的应用，参见屏下指纹识别系统的相关描述，为了简洁，此处不作过多描述。
应理解，本申请实施例中的具体的例子只是为了帮助本领域技术人员更好地理解本申请实施例，而非限制本申请实施例的范围。
应理解，在本申请实施例和所附权利要求书中使用的术语是仅仅出于描述特定实施例的目的，而非旨在限制本申请实施例。例如，在本申请实施例和所附权利要求书中所使用的单数形式的“一种”、“上述”和“该”也旨在包括多数形式，除非上下文清楚地表示其他含义。
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，能够以电子硬件、计算机软件或者二者的结合来实现，为了清楚地说明硬件和软件的可互换性，在上述说明中已经按照功能一般性地描述了各示例的组成及步骤。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。
在本申请所提供的几个实施例中，应该理解到，所揭露的系统、装置，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。另外，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，也可以是电的，机械的或其它的形式连接。
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申请实施例方案的目的。
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，也可以是两个或两个以上单元集成在一个单元中。上述集成的单元既可以采用硬件的形式实现，也可以采用软件功能单元的形式实现。
所述集成的单元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，或者该技术方案的全部或部分可以以软件产品的形式体现出来，该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，可轻易想到各种等效的修改或替换，这些修改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 (34)

  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呈阵列分布的多个指纹识别单元，所述多个指纹识别单元中的每个指纹识别单元包括：
    多个像素单元；
    微透镜，设置在所述多个像素单元的上方；
    多层阻光层，设置在所述微透镜和所述多个像素单元之间，所述多层阻光层中每一层阻光层中均设置有与所述多个像素单元对应的通光小孔，以形成与所述多个像素单元一一对应的多个导光通道；
    其中，所述多个像素单元分别用于接收从所述显示屏上方的手指反射或散射返回的，通过所述微透镜会聚后，再经由所述多个导光通道传输的多个指纹光信号，所述多个指纹光信号用于检测所述手指的指纹信息以进行指纹识别；
    其中，所述多层阻光层包括底层阻光层和中间阻光层，所述中间阻光层包括除所述底层阻光层之外的阻光层，由所述中间阻光层中与所述多个像素单元对应的通光小孔形成的通光区域的通光口径D 2与所述微透镜的最大口径CA满足0.3≤D 2/CA≤1.3，D2为所述中间阻光层所在的平面上，所述通光区域中最远的两点之间的距离。
  2. 根据权利要求1所述的指纹识别装置，其特征在于，所述中间阻光层的下表面至所述微透镜的下表面之间的深度Z 2与所述底层阻光层的下表面至所述微透镜的下表面之间的深度Z 1满足0.1≤Z 2/Z 1≤0.9。
  3. 根据权利要求2所述的指纹识别装置，其特征在于，若所述中间阻光层的下表面至所述微透镜的下表面之间的深度Z 2与所述底层阻光层的下表面至所述微透镜的下表面之间的深度Z 1满足0.1≤Z 2/Z 1≤0.5，所述通光区域的通光口径D 2与所述微透镜的最大口径CA满足0.5≤D 2/CA≤1，所述通光区域的形状为一个圆形。
  4. 根据权利要求2所述的指纹识别装置，其特征在于，若所述中间阻光层的下表面至所述微透镜的下表面之间的深度Z 2与所述底层阻光层的下表面至所述微透镜的下表面之间的深度Z 1满足0.3≤Z 2/Z 1≤0.75，所述通光区域的通光口径D 2与所述微透镜的最大口径CA满足0.5≤D 2/CA≤0.8，所述通光区域的形状为一个圆角矩形或一个花瓣形。
  5. 根据权利要求2所述的指纹识别装置，其特征在于，若所述中间阻光层的下表面至所述微透镜的下表面之间的深度Z 2与所述底层阻光层的下表面至所述微透镜的下表面之间的深度Z 1满足0.65≤Z 2/Z 1≤0.9，所述通光区域的通光口径D 2与所述微透镜的最大口径CA满足0.8≤D 2/CA≤1.2，所述中间阻光层中与所述多个像素单元对应的通光小孔为一一对应的多个独立小孔。
  6. 根据权利要求1至5中任一项所述的指纹识别装置，其特征在于，所述通光区域的通光口径D 2与所述微透镜的最大口径CA满足0.5≤D 2/CA≤1.2。
  7. 根据权利要求2至6中任一项所述的指纹识别装置，其特征在于，所述中间阻光层的下表面至所述微透镜的下表面之间的深度Z 2与所述底层阻光层的下表面至所述微透镜的下表面之间的深度Z 1满足0.5≤Z 2/Z 1≤0.9。
  8. 根据权利要求1至7中任一项所述的指纹识别装置，其特征在于，所述底层阻光层中每个通光小孔的最大口径D 1与所述微透镜的最大口径CA满足0.02≤D 1/CA≤0.4。
  9. 根据权利要求8所述的指纹识别装置，其特征在于，所述底层阻光层中每个通光小孔的最大口径D 1与所述微透镜的最大口径CA满足0.08≤D 1/CA≤0.18。
  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，所述微透镜的曲率半径ROC与所述底层阻光层的下表面至所述微透镜的下表面之间的深度距离Z 1满足0.25≤ROC/Z 1≤0.75。
  11. 根据权利要求10所述的指纹识别装置，其特征在于，所述微透镜的曲率半径ROC与所述底层阻光层的下表面至所述微透镜的下表面之间的深度距离Z 1满足0.4≤ROC/Z 1≤0.6。
  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，所述多层阻光层中从下到上的第i层阻光层中每个通光小孔的位置满足0≤S i/Z 1≤1，其中，S i为所述第i层阻光层中每个通光小孔的中心至所述微透镜在所述第i层阻光层上投影的中心的距离。
  13. 根据权利要求12所述的指纹识别装置，其特征在于，所述第i层阻光层中每个通光小孔的位置满足0.2≤S i/Z 1≤0.5。
  14. 根据权利要求1至13中任一项所述的指纹识别装置，其特征在于， 所述底层阻光层中每个通光小孔为大小相同的圆形孔。
  15. 根据权利要求1至14中任一项所述的指纹识别装置，其特征在于，所述指纹识别装置中微透镜的排列周期P b与所述指纹识别装置中像素单元的排列周期P a满足1＜P b/P a≤4。
  16. 根据权利要求15所述的指纹识别装置，其特征在于，P b/P a＝2，一个所述指纹识别单元包括4个像素单元。
  17. 根据权利要求15所述的指纹识别装置，其特征在于，P b/P a＝3，一个所述指纹识别单元包括9个像素单元。
  18. 根据权利要求1至17中任一项所述的指纹识别装置，其特征在于，所述指纹识别装置中微透镜的排列周期P b满足5μm≤P b≤40μm。
  19. 根据权利要求18所述的指纹识别装置，其特征在于，所述指纹识别装置中微透镜的排列周期P b满足10μm≤P b≤30μm。
  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，所述底层阻光层为所述多个像素单元表面的金属布线层。
  21. 根据权利要求1至20中任一项所述的指纹识别装置，其特征在于，所述指纹识别单元还包括：保护层；
    所述保护层设置于所述底层阻光层上方，且与所述底层阻光层、所述多个像素单元集成在一起。
  22. 根据权利要求21所述的指纹识别装置，其特征在于，所述多个导光通道在所述中间阻光层中的通光小孔重合。
  23. 根据权利要求22所述的指纹识别装置，其特征在于，所述通光区域的形状为圆形、圆角矩形或花瓣形。
  24. 根据权利要求23所述的指纹识别装置，其特征在于，所述指纹识别单元还包括：红外滤光层，
    所述红外滤光层为镀膜生长于所述传感器芯片表面的滤光层，用于截止红外光。
  25. 根据权利要求24所述的指纹识别装置，其特征在于，所述指纹识别单元还包括：粘附层，
    所述粘附层为涂覆于所述红外滤光层表面的平坦透明层，所述中间阻光层设置于所述粘附层上方。
  26. 根据权利要求25所述的指纹识别装置，其特征在于，所述指纹识 别单元还包括：
    第一透明介质层，设置于所述中间阻光层上方并填充所述中间阻光层中的通光小孔。
  27. 根据权利要求26所述的指纹识别装置，其特征在于，所述指纹识别单元还包括：
    颜色滤光层，设置于所述微透镜与所述第一透明介质层之间，所述颜色滤光层包括红色滤光层、蓝色滤光层、绿色滤光层或者白色滤光层。
  28. 根据权利要求21所述的指纹识别装置，其特征在于，所述多个导光通道在所述中间阻光层中的通光小孔相互独立。
  29. 根据权利要求28所述的指纹识别装置，其特征在于，所述中间阻光层设置于所述保护层的上表面。
  30. 根据权利要求29所述的指纹识别装置，其特征在于，所述指纹识别单元还包括：
    第二透明介质层，设置于所述中间阻光层上方并填充所述中间阻光层中的通光小孔。
  31. 根据权利要求30所述的指纹识别装置，其特征在于，所述指纹识别单元还包括：红外滤光层，
    所述红外滤光层为镀膜生长于所述第二透明介质层表面的滤光层，用于截止红外光。
  32. 根据权利要求31所述的指纹识别装置，其特征在于，所述指纹识别单元还包括：
    颜色滤光层，设置于所述红外滤光层上方，所述颜色滤光层包括红色滤光层、蓝色滤光层、绿色滤光层或者白色滤光层。
  33. 根据权利要求32所述的指纹识别装置，其特征在于，所述指纹识别单元还包括：
    第三透明介质层，设置于所述微透镜与所述颜色滤光层之间。
  34. 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33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。
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