CN210605741U

CN210605741U - Fingerprint detection device and electronic equipment

Info

Publication number: CN210605741U
Application number: CN201921791947.3U
Authority: CN
Inventors: 谢浩
Original assignee: Shenzhen Goodix Technology Co Ltd
Current assignee: Shenzhen Goodix Technology Co Ltd
Priority date: 2019-08-06
Filing date: 2019-10-23
Publication date: 2020-05-22
Anticipated expiration: 2029-10-23
Also published as: WO2021022680A1; CN111133442B; CN111133442A; WO2021022488A1

Abstract

The application provides a fingerprint detection's device, the fingerprint that can detect the finger is 3D fingerprint still forged 2D fingerprint, has improved fingerprint detection's security. The device comprises: the light guide layer is used for guiding an inclined light signal which is incident to a finger above the display screen and returns through the finger to the image acquisition unit; the image acquisition unit is used for receiving the optical signal so as to obtain the fingerprint image of the finger, wherein the finger is arranged in a light path between the image acquisition units, and the optical signal received by the image acquisition unit comprises an optical signal of which the receiving surface and the polarization direction of the polarization unit form different included angles, so as to determine whether the fingerprint image is a 3D fingerprint image.

Description

Fingerprint detection device and electronic equipment

This application claims priority from the PCT application with the application number PCT/CN2019/099487, entitled "fingerprint detection device and electronic device", filed by the chinese patent office on 06/08/2019, the entire contents of which are incorporated herein by reference.

Technical Field

The embodiments of the present application relate to the field of biometric identification, and more particularly, to an apparatus and an electronic device for fingerprint detection.

Background

The optical fingerprint module gathers the optical signal who takes place reflection and transmission and return on the finger to according to the fingerprint information of the finger that carries in this optical signal, realize optical fingerprint detection under the screen. However, as long as a fake 2D fingerprint is created, the fingerprint password can be easily cracked, causing a great loss in information security and property security.

SUMMERY OF THE UTILITY MODEL

The embodiment of the application provides a fingerprint detection's device and electronic equipment, can detect that the fingerprint of finger is 3D fingerprint or forged 2D fingerprint, has improved fingerprint detection's security.

In a first aspect, a fingerprint detection apparatus is provided, which is disposed below a display screen of an electronic device, and includes:

the light guide layer is used for guiding an inclined light signal which is incident to a finger above the display screen and returns through the finger to the image acquisition unit;

the image acquisition unit is used for receiving the optical signal so as to obtain the fingerprint image of the finger, wherein the finger is arranged in a light path between the image acquisition units, and the optical signal received by the image acquisition unit comprises an optical signal of which the receiving surface and the polarization direction of the polarization unit form different included angles, so as to determine whether the fingerprint image is a 3D fingerprint image.

In a possible implementation manner, the polarization unit includes a polarization direction, and the light guide layer is configured to guide the optical signals in multiple directions to the image acquisition unit, where included angles between receiving surfaces of the optical signals in the multiple directions and the polarization direction are different.

In one possible implementation, the plurality of directions include a first direction and a second direction, wherein a receiving surface of the optical signal in the first direction is perpendicular to the polarization direction, and a receiving surface of the optical signal in the second direction is parallel to the polarization direction.

In a possible implementation manner, the image capturing unit includes a plurality of sensors, the number of the light guide layers is multiple, and the plurality of light guide layers respectively correspond to the plurality of directions and are configured to respectively guide the light signals in the corresponding directions to the plurality of sensors.

In one possible implementation, the light guide layer includes: a microlens array including a plurality of microlenses for converging the optical signal; at least one light blocking layer is sequentially arranged below the microlens array, each light blocking layer comprises a plurality of openings corresponding to the microlenses, and the direction of a connecting line of the openings corresponding to the same microlens in each light blocking layer is the direction corresponding to the light guide layer.

In one possible implementation, the light guide layer includes a light guide channel array, and the light guide channel array includes: the light guide channels are obliquely arranged, and the oblique direction of the light guide channels is the direction corresponding to the light guide layer; or the optical fibers are vertically arranged, and the optical signals in the direction corresponding to the light guide layer are transmitted in the optical fibers based on total reflection.

In one possible implementation, the light guide layer includes: and the optical function film layer is used for transmitting the optical signal in the direction corresponding to the light guide layer and blocking the optical signal in other directions.

In a possible implementation manner, the image capturing unit includes a sensor, the number of the light guide layer is one, the light guide layer includes a plurality of regions, the plurality of regions respectively correspond to the plurality of directions, and a portion of the light guide layer located in each region is used for guiding the light signal in the corresponding direction to the sensor.

In one possible implementation, the portion of the light guide layer located in each region includes: a microlens array including a plurality of microlenses for converging the optical signal; and the light blocking layers are sequentially arranged below the microlens array, each light blocking layer comprises a plurality of openings corresponding to the microlenses, and the direction of a connecting line of the openings corresponding to the same microlens in each light blocking layer is the direction corresponding to the region.

In one possible implementation, the portion of the light guide layer located in each region includes: the light guide channels are obliquely arranged, and the oblique direction of the light guide channels is the direction corresponding to the region; or, the optical fibers are vertically arranged, and the optical signals in the direction corresponding to the area are transmitted in the optical fibers based on total reflection.

In one possible implementation, the portion of the light guide layer located in each region includes: and the optical function film layer is used for transmitting the optical signal in the direction corresponding to the region and blocking the optical signal in other directions.

In a possible implementation manner, the polarization unit includes a plurality of polarization directions, and the light guide layer is configured to guide the optical signal in the target direction to the image acquisition unit, where included angles between a receiving surface of the optical signal in the direction and the plurality of polarization directions are different.

In one possible implementation, the plurality of polarization directions form a centrosymmetric pattern.

In one possible implementation, the centrosymmetric pattern is a circle or a square.

In a possible implementation manner, the image capturing unit includes a plurality of sensors, the number of the light guide layers is multiple, and the plurality of light guide layers are used for guiding the light signals in the target direction to the plurality of sensors respectively.

In a possible implementation manner, the image capturing unit includes one sensor, the number of the light guide layers is one, and the light guide layers are used for guiding the light signal in the target direction to the sensor.

In one possible implementation, the light guide layer includes: a microlens array including a plurality of microlenses for converging the optical signal; and the light blocking layers are sequentially arranged below the microlens array, each light blocking layer comprises a plurality of openings corresponding to the microlenses, and the direction of a connecting line of the openings corresponding to the same microlens in each light blocking layer is the target direction.

In one possible implementation, the light guide layer includes a light guide channel array, and the light guide channel array includes: the light guide channels are obliquely arranged, and the oblique direction of the light guide channels is the target direction; or, a plurality of optical fibers, the optical fibers being arranged vertically, the optical signal in the target direction being transmitted in the optical fibers based on total reflection.

In one possible implementation, the light guide layer includes a light guide channel array, and the light guide channel array includes: and the optical function film layer is used for transmitting the optical signal in the target direction and blocking the optical signal in other directions.

In one possible implementation, the polarization unit is located within the display screen.

In one possible implementation, the polarization unit is located above the light guide layer.

In a possible implementation manner, the polarization unit is formed on the upper surface of the light guide layer through a plated film, or the polarization unit is attached to the upper surface of the light guide layer through an optical adhesive.

In one possible implementation, the apparatus further includes: and the processor is used for determining whether the fingerprint image is a 3D fingerprint image according to the definition of the fingerprint image in different areas.

In one possible implementation, the processor is specifically configured to: determining that the fingerprint image is a 3D fingerprint image when the definitions of areas corresponding to optical signals of which the receiving surfaces form different included angles with the polarization directions of the polarization units in the fingerprint image are different; and when the definition is the same, determining that the fingerprint image is not the 3D fingerprint image.

In one possible implementation, the apparatus further includes: and the filter layer is arranged in a light path between the display screen and the image acquisition unit and used for filtering optical signals in a non-target waveband so as to transmit the optical signals in the target waveband to the image acquisition unit.

In one possible implementation, the filter layer is disposed above the light guide layer.

In a second aspect, an electronic device is provided, comprising:

a display screen; and the number of the first and second groups,

the apparatus of the first aspect or any possible implementation of the first aspect.

Based on the technical scheme, the polarization unit is arranged in a light path from the finger to the image acquisition unit, and the optical signals received by the image acquisition unit comprise optical signals of which the receiving surfaces and the polarization directions of the polarization unit form different included angles. In this way, for the optical signal reflected by the 3D fingerprint, the energy of the S-wave and the P-wave included in the optical signal whose receiving surface forms different included angles with the polarization direction of the polarization unit is different; the reflection generated on the forged 2D fingerprint is diffuse reflection, and the energy of the optical signals of which the receiving surfaces form different included angles with the polarization direction is the same, so that the difference exists between the formed 3D fingerprint image and the fingerprint image of the 2D fingerprint, and whether the finger is the 3D fingerprint can be judged based on the difference, thereby improving the safety of fingerprint detection.

Drawings

Fig. 1A and 1B are schematic views of an electronic device to which the present application can be applied.

Fig. 2A and 2B are schematic cross-sectional views of the electronic device shown in fig. 1A and 1B along a direction a-a', respectively.

Fig. 3 is a schematic block diagram of an apparatus for fingerprint detection according to an embodiment of the present application.

Fig. 4 is a schematic view of a receiving surface.

Fig. 5 is a schematic view of a microlens and a light blocking layer of an embodiment of the present application.

Fig. 6 is a schematic view of a microlens and a light blocking layer of an embodiment of the present application.

Fig. 7 is a schematic view of a microlens and a light blocking layer of an embodiment of the present application.

Fig. 8 is a schematic diagram of an array of light-conducting channels according to an embodiment of the present application.

Fig. 9 is a schematic diagram of a light-guiding channel array according to an embodiment of the present application.

Fig. 10 is a schematic diagram of an array of light-conducting channels according to an embodiment of the present application.

Fig. 11 is a schematic view of an optically functional film layer according to an embodiment of the present disclosure.

Fig. 12 is a schematic view of an optically functional film layer of an embodiment of the present application.

FIG. 13 is a schematic view of a receiving surface when multiple sensors are employed in an embodiment of the present application.

FIG. 14 is a schematic view of a receiving surface when multiple sensors are employed in an embodiment of the present application.

FIG. 15 is a schematic view of a receiving surface when a single sensor is employed in an embodiment of the present application.

Fig. 16 is a schematic view of a polarizing plate of an embodiment of the present application.

Fig. 17 is a schematic view of a polarizing plate of an embodiment of the present application.

Fig. 18 is a schematic diagram of fingerprint detection of a 3D fingerprint according to an embodiment of the present application.

Fig. 19 is a schematic diagram of S light and P light.

Fig. 20 is a schematic diagram of the fingerprint image obtained based on fig. 18.

Fig. 21 is a schematic diagram of fingerprint detection of a 2D fingerprint according to an embodiment of the present application.

Detailed Description

The technical solution in the present application will be described below with reference to the accompanying drawings.

It should be understood that the embodiments of the present application can be applied to fingerprint systems, including but not limited to optical, ultrasonic or other fingerprint detection systems and medical diagnostic products based on optical, ultrasonic or other fingerprint imaging, and the embodiments of the present application are only illustrated by way of example of an optical fingerprint system, but should not constitute any limitation to the embodiments of the present application, and the embodiments of the present application are also applicable to other systems using optical, ultrasonic or other imaging technologies, and the like.

As a common application scenario, the optical fingerprint system provided by the embodiment of the application can be applied to smart phones, tablet computers and other mobile terminals or other electronic devices with display screens; more specifically, in the electronic device, the optical fingerprint module may be disposed in a partial area or an entire area below the display screen, so as to form an Under-screen (or Under-screen) optical fingerprint system. Or, the optical fingerprint module can also be partially or completely integrated inside the display screen of the electronic device, so as to form an In-display or In-screen optical fingerprint system.

Optical fingerprint sensing under screens technology uses light returning from the top surface of the device display assembly for fingerprint sensing and other sensing operations. The returned light carries information of an object, such as a finger, in contact with the top surface, and optical fingerprint detection of a specific optical sensor module located below the display screen is realized by collecting and detecting the light returned by the finger. The design of the optical sensor module may be such that the desired optical imaging is achieved by appropriately configuring the optical elements for collecting and detecting the returned light.

Fig. 1A and 2A show schematic views of an electronic device to which embodiments of the present application may be applied. Fig. 1A and 2A are schematic orientation diagrams of the electronic device 10, and fig. 1B and 2B are schematic partial cross-sectional views of the electronic device 10 shown in fig. 1A and 2A along a direction a-a', respectively.

The electronic device 10 includes a display screen 120 and an optical fingerprint module 130. Wherein, the optical fingerprint module 130 is disposed in a local area below the display screen 120. The optical fingerprint module 130 includes an optical fingerprint sensor including a sensing array 133 having a plurality of optical sensing units 131 (also referred to as pixels, light sensing pixels, pixel units, etc.). The sensing area or the sensing area where the sensing array 133 is located is the fingerprint detection area 103 of the optical fingerprint module 130. As shown in fig. 1A, the fingerprint detection area 103 is located in a display area of the display screen 120. In an alternative implementation, the optical fingerprint module 130 is disposed at other positions, such as at the side of the display screen 120 or at the edge non-light-transmitting area of the electronic device 10, and the optical path is designed to guide the optical signal from at least a part of the display area of the display screen 120 to the optical fingerprint module 130, so that the fingerprint detection area 103 is actually located at the display area of the display screen 120.

It should be understood that the area of the fingerprint detection area 103 may be different from the area of the sensing array 133 of the optical fingerprint module 130, for example, the optical path design through lens imaging, the reflective folding optical path design or other optical path designs such as light convergence or reflection, so that the area of the fingerprint detection area 103 of the optical fingerprint module 130 is larger than the area of the sensing array 133 of the optical fingerprint module 130. In other alternative implementations, if the light path is guided by, for example, light collimation, the fingerprint detection area 103 of the optical fingerprint module 130 may be designed to substantially correspond to the area of the sensing array 133 of the optical fingerprint module 130.

Therefore, when the user needs to unlock or otherwise verify the fingerprint of the electronic device 10, the user only needs to press a finger on the fingerprint detection area 103 of the display screen 120, so as to input the fingerprint. Since fingerprint detection can be implemented in the screen, the electronic device 10 with the above structure does not need to reserve a special space on the front surface thereof to set a fingerprint key (such as a Home key), so that a full-screen scheme can be adopted, that is, the display area of the display screen 120 can be substantially extended to the front surface of the whole electronic device 10.

As an alternative implementation, as shown in FIG. 1B, the optical fingerprint module 130 includes a light detection portion 134 and an optical assembly 132. The light detecting portion 134, which includes the sensing array 133 and the reading circuit and other auxiliary circuits electrically connected to the sensing array 133, can be fabricated on a chip (Die) by a semiconductor process to form an optical fingerprint sensor (also referred to as an optical fingerprint chip, sensor chip, etc.). The sensing array 133 is specifically a Photo detector (Photo detector) array, which includes a plurality of Photo detectors distributed in an array, and the Photo detectors can be used as the optical sensing units as described above. The optical assembly 132 may be disposed above the sensing array 133 of the light detecting portion 134, and may specifically include a Filter layer (Filter) for filtering out ambient light penetrating through the finger, a light guiding layer or a light path guiding structure for guiding reflected light reflected from the surface of the finger to the sensing array 133 for fingerprint detection, and other optical elements.

In particular implementations, the optical assembly 132 may be packaged with the same optical fingerprint component as the light detection portion 134. For example, the optical component 132 may be packaged in the same optical fingerprint chip as the optical detection portion 134, or the optical component 132 may be disposed outside the chip where the optical detection portion 134 is located, for example, the optical component 132 is attached to the chip, or some components of the optical component 132 are integrated into the chip.

There are various implementations of the light guiding layer of the optical assembly 132. For example, the light guide layer may be specifically a Collimator (collimater) layer made of a semiconductor silicon wafer, and has a plurality of collimating units or a micro-hole array, the collimating units may be specifically small holes, light rays perpendicularly incident to the collimating units may pass through and be received by optical sensing units below the collimating units in reflected light reflected by a finger, and light rays with an excessively large incident angle are attenuated by multiple reflections inside the collimating units, so that each optical sensing unit can basically only receive reflected light reflected by a fingerprint pattern directly above the optical sensing unit, and the sensing array 133 can detect a fingerprint image of the finger.

In another implementation, the light guide layer may also be an optical Lens (Lens) layer having one or more Lens units, such as a Lens group composed of one or more aspheric lenses, for converging the reflected light reflected from the finger to the sensing array 133 of the light detection part 134 therebelow, so that the sensing array 133 may be imaged based on the reflected light to obtain the fingerprint image of the finger. Optionally, the optical lens layer may further form a pinhole in an optical path of the lens unit, and the pinhole may cooperate with the optical lens layer to enlarge a field of view of the optical fingerprint module 130, so as to improve a fingerprint imaging effect of the optical fingerprint module 130.

In other implementations, the light guide layer may also specifically adopt a Micro-Lens (Micro-Lens) layer, the Micro-Lens layer has a Micro-Lens array formed by a plurality of Micro-lenses, which may be formed above the sensing array 133 of the light detection portion 134 through a semiconductor growth process or other processes, and each Micro-Lens may respectively correspond to one of the sensing units of the sensing array 133. Other optical film layers, such as dielectric layers or passivation layers, may also be formed between the microlens layer and the sensing unit. Further, a light blocking layer (also referred to as a light blocking layer, etc.) having micro holes may be further included between the microlens layer and the sensing unit, wherein the micro holes are formed between the corresponding microlenses and the sensing unit, and the light blocking layer may block optical interference between adjacent microlenses and the sensing unit, and enable light corresponding to the sensing unit to be converged inside the micro holes through the microlenses and transmitted to the sensing unit through the micro holes for optical fingerprint imaging.

It should be understood that several implementations of the light guide layer described above may be used alone or in combination. For example, a microlens layer may be further disposed above or below the collimator layer or the optical lens layer. Of course, when the collimator layer or the optical lens layer is used in combination with the microlens layer, the specific lamination structure or optical path thereof may need to be adjusted according to actual needs.

As an alternative implementation manner, the display screen 120 may adopt a display screen having a self-Light Emitting display unit, such as an Organic Light-Emitting Diode (OLED) display screen or a Micro-LED (Micro-LED) display screen. Taking an OLED display screen as an example, the optical fingerprint module 130 may use a display unit (i.e., an OLED light source) of the OLED display screen 120 located in the fingerprint detection area 103 as an excitation light source for optical fingerprint detection. When the finger 140 is pressed on the fingerprint detection area 103, the display screen 120 emits a beam of light 111 to the finger 140 above the fingerprint detection area 103, and the light 111 is reflected on the surface of the finger 140 to form reflected light or scattered light by scattering inside the finger 140. In the related patent application, the above-described reflected light and scattered light are also collectively referred to as reflected light for convenience of description. Because the ridges 141 and the valleys 142 of the fingerprint have different light reflection capabilities, the reflected light 151 from the ridges and the reflected light 152 from the valleys have different light intensities, and after passing through the optical assembly 132, the reflected light is received by the sensing array 133 in the optical fingerprint module 130 and converted into corresponding electrical signals, i.e., fingerprint detection signals. Fingerprint image data can be obtained based on the fingerprint detection signal, and fingerprint matching verification is further performed, so that an optical fingerprint detection function is realized in the electronic device 10.

In other implementations, the optical fingerprint module 130 may also use an internal light source or an external light source to provide an optical signal for fingerprint detection. In this case, the optical fingerprint module 130 may be suitable for a non-self-luminous display screen, such as a liquid crystal display screen or other passive luminous display screen. Taking an application to a liquid crystal display screen having a backlight module and a liquid crystal panel as an example, to support the underscreen fingerprint detection of the liquid crystal display screen, the optical fingerprint system of the electronic device 10 may further include an excitation light source for optical fingerprint detection, where the excitation light source may specifically be an infrared light source or a light source of non-visible light with a specific wavelength, and may be disposed below the backlight module of the liquid crystal display screen or in an edge area below a protective cover plate of the electronic device 10, and the optical fingerprint module 130 may be disposed below the edge area of the liquid crystal panel or the protective cover plate and guided through a light path so that the fingerprint detection light may reach the optical fingerprint module 130; alternatively, the optical fingerprint module 130 may be disposed below the backlight module, and the backlight module may open holes or perform other optical designs on film layers such as a diffusion sheet, a brightness enhancement sheet, and a reflection sheet to allow the fingerprint detection light to pass through the liquid crystal panel and the backlight module and reach the optical fingerprint module 130. When the optical fingerprint module 130 is used to provide an optical signal for fingerprint detection by using an internal light source or an external light source, the detection principle is consistent with the above description.

It should be appreciated that in particular implementations, the electronic device 10 may further include a transparent protective cover plate, which may be a glass cover plate or a sapphire cover plate, positioned over the display screen 120 and covering the front surface of the electronic device 10. Therefore, in the embodiment of the present application, the pressing of the finger on the display screen 120 actually means pressing on the cover plate above the display screen 120 or the surface of the protective layer covering the cover plate.

The electronic device 10 may further include a circuit board 150, and the circuit board 150 is disposed below the optical fingerprint module 130. The optical fingerprint module 130 can be adhered to the circuit board 150 by a back adhesive and electrically connected to the circuit board 150 by soldering a pad and a metal wire. Optical fingerprint module 130 may be electrically interconnected and signal-routed to other peripheral circuits or other components of electronic device 10 via circuit board 150. For example, the optical fingerprint module 130 may receive a control signal of a processing unit of the electronic device 10 through the circuit board 150, and may also output a fingerprint detection signal from the optical fingerprint module 130 to the processing unit or the control unit of the terminal device 10, or the like, through the circuit board 150.

In some implementations, the optical fingerprint module 130 may include only one optical fingerprint sensor, and the area of the fingerprint detection area 103 of the optical fingerprint module 130 is small and the position is fixed, so that the user needs to press the finger to a specific position of the fingerprint detection area 103 when inputting the fingerprint, otherwise the optical fingerprint module 130 may not collect the fingerprint image and cause poor user experience. In other alternative embodiments, the optical fingerprint module 130 may include a plurality of optical fingerprint sensors. A plurality of optics fingerprint sensor can be through the mode of concatenation set up side by side the below of display screen 120, just a plurality of optics fingerprint sensor's response area constitutes jointly optics fingerprint module 130's fingerprint detection area 103. Thereby the fingerprint detection area 103 of optical fingerprint module 130 can extend to the main area of the lower half of display screen, extend to the finger and press the region conventionally promptly to realize blind formula fingerprint input operation of pressing. Further, when the number of the optical fingerprint sensors is sufficient, the fingerprint detection area 103 may also be extended to a half display area or even the entire display area, thereby realizing half-screen or full-screen fingerprint detection.

For example, the electronic device 10 shown in fig. 2A and 2B, the optical fingerprint module 130 in the electronic device 10 includes a plurality of optical fingerprint sensors, the plurality of optical fingerprint sensors may be arranged side by side below the display screen 120 in a manner such as splicing, and sensing areas of the plurality of optical fingerprint sensors jointly form the fingerprint detection area 103 of the optical fingerprint module 130.

Optionally, with a plurality of optics fingerprint sensor of optics fingerprint module 130 are corresponding, can include a plurality of leaded light layers in the optical subassembly 132, every leaded light layer corresponds an optics fingerprint sensor respectively to laminate respectively and set up in its corresponding optics fingerprint sensor's top. Alternatively, the plurality of optical fingerprint sensors may share a single light guiding layer, i.e. the light guiding layer has a large enough area to cover the sensing array of the plurality of optical fingerprint sensors.

In addition, the optical assembly 132 may further include other optical elements, such as a Filter (Filter) or other optical film, which may be disposed between the light guide layer and the optical fingerprint sensor, or between the display screen 120 and the light guide layer, and mainly used to isolate the influence of external interference light on the detection of the optical fingerprint. Wherein the optical filter may be used to filter out ambient light that penetrates a finger and enters the optical fingerprint sensor through the display screen 120. Similar to the light guide layer, the optical filter may be respectively disposed for each optical fingerprint sensor to filter out interference light, or may also cover the plurality of optical fingerprint sensors simultaneously with one large-area optical filter.

The light guide layer can also be replaced by an optical Lens (Lens), and a small hole can be formed above the optical Lens through a shading material and matched with the optical Lens to converge fingerprint detection light to an optical fingerprint sensor below the optical Lens so as to realize fingerprint imaging. Similarly, each optical fingerprint sensor may be configured with an optical lens for fingerprint imaging, or the optical fingerprint sensors may use the same optical lens for light convergence and fingerprint imaging. In other alternative embodiments, each optical fingerprint sensor may even have two sensing arrays (Dual Array) or multiple sensing arrays (Multi-Array), and two or more optical lenses are configured to cooperate with the two or more sensing arrays to perform optical imaging, so as to reduce the imaging distance and enhance the imaging effect.

When fingerprint detection is carried out, a light source irradiates a finger above a display screen, and an optical fingerprint sensor collects an optical signal which is reflected or scattered by the finger and returns, so that fingerprint information of the finger is acquired. However, if a fingerprint password can be easily cracked by copying a fingerprint image of a finger and performing fingerprint detection using the copied fingerprint image, a great loss is caused to information security and property security.

Therefore, the embodiment of the application provides a scheme of fingerprint detection, can detect whether the fingerprint of finger is 3D fingerprint or forged 2D fingerprint, has improved fingerprint detection's security.

Fig. 3 is a schematic block diagram of an apparatus for fingerprint detection according to an embodiment of the present application. The device 300 is disposed below a display screen of an electronic device to implement optical fingerprint detection under the screen. Wherein the apparatus 300 comprises:

the light guide layer 310 is used for guiding an inclined light signal which is incident to a finger above the display screen and returns through the finger to the image acquisition unit 320; and the number of the first and second groups,

an image acquisition unit 320 for receiving the optical signal to acquire a fingerprint image of the finger.

Wherein, a Polarization (POL) unit 330 is disposed in an optical path from the finger to the image acquisition unit. The optical signals received by the image acquisition unit 320 include optical signals whose receiving surfaces form different included angles with the polarization direction of the polarization unit 330, so as to determine whether the fingerprint image is a 3D fingerprint image.

In this embodiment, a polarization unit is disposed in a light path from a finger to the image acquisition unit, and the optical signal received by the image acquisition unit includes optical signals whose receiving surfaces form different included angles with the polarization direction of the polarization unit. In this way, for the optical signal reflected by the 3D fingerprint, the energy of the S-wave and the P-wave included in the optical signal whose receiving surface forms different included angles with the polarization direction of the polarization unit is different; the reflection generated on the forged 2D fingerprint is diffuse reflection, and the energy of the optical signals of which the receiving surfaces form different included angles with the polarization direction is the same, so that the difference exists between the formed 3D fingerprint image and the fingerprint image of the 2D fingerprint, and whether the finger is the 3D fingerprint can be judged based on the difference, thereby improving the safety of fingerprint detection.

The receiving surface is a plane formed by the incident light and the reflected light, i.e. a transmission surface on which the optical signal is located, and therefore the receiving surface can also be referred to as an incident surface. The receiving surface is perpendicular to the display screen and the light sensing surface of the pixels of the image capturing unit, i.e. the Photodiodes (PDs).

In the embodiment of the present application, the tilt angle of the optical signal returned by the finger may be, for example, between 10 degrees and 50 degrees.

The image acquisition unit 320 may refer to the foregoing description of the light detection portion 134 in fig. 1B and 2B, and will not be described herein again.

The embodiment of the present application does not limit the position of the polarization unit 330. The polarization unit 330 may be disposed at any position in the optical path between the finger and the image capturing unit 320.

For example, the polarization unit 330 is disposed within the display screen, such as above an OLED light emitting layer of the display screen.

For another example, the polarization unit 330 is disposed above the light guide layer 310, such as being formed on the upper surface of the light guide layer 310 by a plating film, or being attached to the upper surface of the light guide layer 310 by an optical adhesive. Wherein the refractive index of the optical cement can be similar to that of the polarization unit 330 to avoid loss.

For another example, the polarization unit 330 is disposed above the image capturing unit 320, such as formed on the upper surface of the image capturing unit 320 by plating, or adhered to the upper surface of the image capturing unit 320 by optical adhesive. Wherein the refractive index of the optical cement can be similar to that of the polarization unit 330 to avoid loss.

Generally, for an LCD display screen or an OLED display screen, the polarization unit 330 may be disposed inside the display screen to simultaneously implement the related functions of the display screen. For the micro led (micro led) display screen, since the polarization unit 330 is not needed in the display screen, the polarization unit 330 may be disposed in the fingerprint detection apparatus 300, for example, on the upper surface of the light guide layer 310 or the image collecting unit 320, so as to determine whether the fingerprint is true or false.

In embodiments of the present application, the light guide layer may be used to guide light signals within one or more slanted receiving planes. One or more polarization directions may be disposed on the polarization unit 330. Through the cooperation between the polarization unit 330 and the light guide layer 310, the light signals received by the image acquisition unit 320 include light signals with different included angles between the receiving surface thereof and the polarization direction of the polarization unit 300, so as to determine whether the fingerprint of the finger is a 3D fingerprint or a forged 2D fingerprint.

The embodiments of the present application provide two ways to discriminate authenticity of a fingerprint, which will be described in detail with reference to fig. 4 to 17. Hereinafter, the horizontal plane is a plane where a display screen of the electronic device is located. The horizontal direction refers to a direction parallel to the display screen.

Mode 1

The polarization unit 330 includes a polarization direction, and the light guide layer 310 is used for guiding light signals of multiple directions to the image capturing unit 320. And the receiving surfaces of the optical signals in the multiple directions and the polarization directions form different included angles.

Wherein the receiving surface of the optical signal is perpendicular to the display screen, and the polarization direction of the polarization unit 330 is parallel to the display screen, so that the polarization direction is perpendicular to the receiving surface. However, the angle between the polarization direction and the receiving surface may be different.

For example, the plurality of directions includes a first direction and a second direction. Wherein the receiving surface of the optical signal in the first direction is perpendicular to the polarization direction, and the receiving surface of the optical signal in the second direction is parallel to the polarization direction. It should be understood that multiple directions of light signals can be transmitted in the same receiving plane, and in general, the light guide layer 310 is used to guide one direction of light signals to the image acquisition unit 320.

Referring to fig. 4, the polarization direction of the polarizer 330 is shown by a dotted arrow, the receiving surface 3101 is parallel to the polarization direction of the polarizer 330 (the angle is 0 degrees), and the receiving surface 3102 is perpendicular to the polarization direction of the polarizer 330 (the angle is 90 degrees). The angle between the receiving surface and the polarization direction may also be other values, such as the receiving surface 3103 shown in fig. 4.

In this mode 1, in order to realize that the included angles between the receiving surface of the optical signal and the polarization direction of the polarization unit 330 are different, the optical signal in different receiving surfaces can be guided to the image capturing unit 320 by using the light guiding layer 310 under the condition that the polarization direction of the polarization unit 330 is kept unchanged, so that the optical signal received by the image capturing unit 320 includes the optical signal whose receiving surface and polarization direction form different included angles.

In this mode 1, the image capturing unit 320 may include a sensor, such as shown in fig. 1A and 1B; the image acquisition unit 320 may also include a plurality of sensors, such as shown in fig. 2A and 2B.

When the image pickup unit 320 includes a plurality of sensors, the number of the light guide layer 310 is plural. The light guide layers 310 respectively correspond to the directions. Wherein the plurality of light guide layers 310 are configured to guide the light signals in the corresponding directions to the plurality of sensors, respectively.

Wherein each light guiding layer 310 can be implemented in the following ways.

In one implementation, each light guiding layer 310 includes:

a microlens array 311 including a plurality of microlenses for condensing the optical signal;

at least one light blocking layer 312 sequentially disposed below the microlens array 311, each light blocking layer including a plurality of openings corresponding to the plurality of microlenses, wherein a direction of a line connecting openings corresponding to the same microlens in each light blocking layer is a direction corresponding to the light guiding layer 310.

Wherein, the projection of the light-gathering surface of each micro lens on a plane perpendicular to the optical axis thereof can be rectangular or circular. The light-condensing surface of the microlens is a surface for condensing light. The light-condensing surface may be a spherical surface or an aspherical surface. Preferably, curvatures of the light-condensing surfaces in all directions are the same, so that focuses of the micro lenses in imaging light rays in all directions are located at the same position, and imaging quality is guaranteed.

Each microlens may correspond to one pixel in the image pickup unit 320. The oblique optical signals converged by each micro lens pass through the openings corresponding to the micro lenses in each light blocking layer and reach corresponding pixels.

Since the apertures in the light-blocking layers are used to guide light, in order for a tilted light signal to reach the image capture unit 320, the lines connecting the apertures in each light-blocking layer corresponding to the same microlens should be tilted at an angle equal to or approximately equal to the tilt angle of the light signal.

The light blocking layer 312 may be provided with one or more layers.

For example, as shown in fig. 5, when a light-blocking layer 312 is used, the light-blocking layer 312 may be integrated into the image capturing unit 320, for example, by using a metal mask (mask) to form a light-blocking layer above the pixel array of the image capturing unit 320.

For example, as shown in fig. 6 and 7, when a plurality of light-blocking layers 312 are used, the inclination angle of the connecting line of the openings corresponding to the same microlens in each light-blocking layer determines the inclination angle of the optical signal reaching the sensor. The openings corresponding to the same micro-lens in each light blocking layer are sequentially shifted from top to bottom, so that optical signals in the corresponding directions are transmitted to the corresponding pixels. Among them, the last light blocking layer 312 in fig. 6 and 7 may be integrated in the image capturing unit 320, thereby improving reliability.

The size of the openings corresponding to the same microlens in each light blocking layer can be sequentially reduced from top to bottom, so that the optical signal within a certain angle range is guided to the corresponding pixel, for example, as shown in fig. 7.

A transparent medium layer may also be disposed between the microlens array 311, the light blocking layer 312, and the image capturing unit 320. The transparent medium layer may be used to connect the microlens array 311, the light blocking layer 312, and the image capturing unit 320, and fill the opening in the at least one light blocking layer. The transparent medium layer can be transparent to optical signals in a target wavelength band, that is, optical signals in a wavelength band required for fingerprint detection, for example, the transparent medium layer can be made of oxide or nitride.

The transparent dielectric layer may include multiple layers to achieve protection, transition, and buffering functions, respectively. For example, a transition layer may be disposed between the inorganic material layer and the organic material layer to achieve tight connection; for another example, a protective layer may be provided on the easily oxidizable layer to achieve protection.

In another implementation, each light guide layer 310 includes an array of light guide channels 313 for transmitting optical signals in one direction.

For example, the light guide channel array 313 includes a plurality of light guide channels, and the light guide channels are obliquely arranged. The inclined direction of the light guide channel is the direction corresponding to the light guide layer 310. The light guide channel may be formed of an air through hole or a light transmitting material, etc.

As shown in fig. 8, the light guide layer 310 is disposed parallel to the display screen 340, the light guide channel is an inclined channel, and has a certain inclination angle with respect to the surface of the light guide layer 310, so that only the light signal with the transmission direction the same as the inclined direction of the light guide channel can be transmitted to the image capturing unit 320 through the light guide channel, and the light signals in other directions are blocked.

Of course, a light guide channel perpendicular to the surface of the light guide layer 310 may be formed on the light guide layer 310, and then the light guide layer 310 may be tilted to a certain angle with respect to the display screen 340, for example, as shown in fig. 9. At this time, the optical signal having the same transmission direction as the inclined direction of the light guide layer 310 can be transmitted to the image capturing unit 320 through the light guide channel, while the optical signals in other directions are blocked.

For another example, the light guide channel array 313 includes a plurality of optical fibers, and the optical fibers are vertically arranged. The optical signal in the direction corresponding to the light guide layer 310 is transmitted in the optical fiber based on total reflection.

The transmission of optical signals in optical fibers is based on the principle of total reflection. Because of the refractive index difference between the fiber core and the cladding of the optical fiber, the optical signal meeting the total reflection angle generates total reflection at the interface of the fiber core and the cladding, thereby locking the optical signal meeting the conditions in the fiber core and transmitting the optical signal forwards. As shown in fig. 10, the optical signal enters at one end of the optical fiber, and exits from the other end of the optical fiber after being totally reflected at least once in the optical fiber.

In another implementation, each light guide layer 310 includes an optical function film layer 314 for transmitting the light signal in the direction corresponding to the light guide layer 310 and blocking the light signal in other directions.

The optical function film layer 314 may be, for example, a grating film or a prism film.

For example, as shown in fig. 11, the optical function film layer 314 may select a fixed direction of optical signals among the optical signals in various directions and allow the optical signals to exit from the optical function film layer 314, so that the optical signals reach the image capturing unit 320. While other directions of the optical signal are attenuated or reflected so as not to exit the optical functional film layer 314.

Further, the optical function film layer 314 may refract the optical signal so that the optical signal can be vertically incident on the pixel of the image capturing unit 320.

For example, as shown in fig. 12, the optical functional film 314 may transmit the optical signal in the direction a and refract the optical signal, so that the optical signal can vertically exit from the optical functional film 314 and be incident on the pixel in the image capturing unit 320. When the pixel vertically receives the optical signal, the quantum efficiency is highest, so that the optimal photoelectric conversion efficiency can be obtained, and the fingerprint detection performance is improved.

The optically functional film layer 314 may be integrated in the image acquisition unit 320; alternatively, the optical function film layer 314 is disposed above the image capturing unit 320 as a separate device from the image capturing unit 320, and is attached to the upper surface of the image capturing unit 320 by, for example, optical adhesive.

It should be understood that each of the light guide layers 310 described above corresponds to one sensor and may be disposed above the corresponding sensor, but the present application is not limited thereto. The plurality of sensors may also share a unitary light guiding layer 310, the light guiding layer 310 having an area large enough to cover the plurality of sensors. At this time, the light guide layer 310 includes a plurality of regions respectively corresponding to the plurality of directions, and the plurality of sensors are respectively disposed below the plurality of regions. The portions of the light guiding layer 310 within each region are used to guide light signals in the corresponding direction to the corresponding sensor.

When the image capturing unit 320 includes a sensor, a light guiding layer 310 may be disposed over the sensor. The light guide layer 310 includes a plurality of regions respectively corresponding to the plurality of directions. The portions of the light guiding layer 310 within the respective regions are used to guide the light signals in the corresponding directions to the sensors.

In one implementation, the portions of the light guiding layer 310 within each region include: a microlens array including a plurality of microlenses for converging the optical signal; and at least one light blocking layer which is sequentially arranged below the microlens array, wherein each light blocking layer comprises a plurality of openings corresponding to the microlenses. And the direction of the connecting line of the openings corresponding to the same microlens in each light blocking layer is the direction corresponding to the region.

In another implementation, the portion of the light guiding layer located within each region includes: the light guide channels are obliquely arranged, and the oblique direction of the light guide channels is the direction corresponding to the region; or, the optical fibers are vertically arranged, and the optical signals in the direction corresponding to the area are transmitted in the optical fibers based on total reflection.

In another implementation, the portion of the light guiding layer located within each region includes: and the optical function film layer is used for transmitting the optical signal in the direction corresponding to the region and blocking the optical signal in other directions.

It should be understood that, for the portion of the light guide layer 310 located in each region, the structure thereof can refer to the related description with respect to fig. 5 to 12, and for brevity, the description is omitted here.

When the image capturing unit 320 includes a plurality of sensors, a plurality of light guide layers corresponding to the plurality of sensors are respectively used for guiding the light signals in different directions to the corresponding sensors. For example, as shown in the top view of fig. 13, the dashed arrows indicate the polarization directions of the linear polarization units 330, and the solid arrows indicate the projections of the receiving surfaces of the optical signals in the horizontal plane. The image capturing unit 320 includes two sensors, the sensing regions corresponding to the two sensors are the sensing region 341 and the sensing region 342, and a light guiding layer is disposed above each of the two sensors. One of the light guide layers is used for transmitting the optical signal in the first direction, and it is assumed that the receiving surface of the optical signal in the first direction is a receiving surface 1302 in fig. 4, which is perpendicular to the polarization direction of the polarizer 330; the other light guide layer is used to transmit the optical signal in the second direction, and it is assumed that the receiving surface of the optical signal in the second direction is a receiving surface 1301 in fig. 4, which is parallel to the polarization direction of the polarizer 330. Thus, the two sensors can receive optical signals in the receiving plane perpendicular and parallel to the polarization direction, respectively.

It should be understood that the light guide layers corresponding to the two sensors may be identical light guide layers, i.e. two light guide layers are used for guiding light signals with the same tilt angle. When the fingerprint module is assembled, one light guide layer can be horizontally rotated by 90 degrees relative to the other light guide layer, so that the inclination angles of the optical signals guided by the two light guide layers are the same, but the receiving surfaces are perpendicular to each other, which is the case shown in fig. 13, for example.

For another example, as shown in fig. 14, when the image capturing unit 320 includes 4 sensors, 4 identical light guide layers are provided, and when the 4 light guide layers are installed, the 4 light guide layers may be sequentially horizontally rotated by 90 degrees, so as to guide the light signals in the 4 directions to the corresponding 4 sensors. Wherein, the optical signals received by the two sensors positioned on the diagonal are positioned on the same receiving surface, but the transmission directions of the optical signals are different.

When the image acquisition unit comprises a sensor, a light guide layer is arranged above the sensor. The parts of the light guide layer, which are positioned in different areas, are respectively used for guiding light signals in different directions to the sensor. For example, as shown in the top view of fig. 15, the dashed arrows indicate the polarization directions of the linear polarization units 330, and the solid arrows indicate the projections of the receiving surfaces of the optical signals in the horizontal plane. The image capturing unit 320 includes a sensor, and the sensing area corresponding to the sensor is a sensing area 343. One part of the light guide layer is used for guiding the light signals in the first direction to corresponding pixels in the sensor, and the other part of the light guide layer is used for guiding the light signals in the second direction to corresponding pixels in the sensor. The receiving surfaces 1301 and 1302 of the optical signals in the first direction and the second direction are respectively, and the receiving surface 1301 and the receiving surface 1302 are parallel and perpendicular to the polarization direction.

Mode 2

The polarization unit 330 includes a plurality of polarization directions, and the light guide layer 310 is configured to guide the optical signal in the same direction (e.g., a target direction) to the image capturing unit 320, where an included angle between a receiving surface of the optical signal in the target direction and the plurality of polarization directions is different.

In this mode 2, in order to realize that the included angles between the oblique receiving surface of the optical signal and the polarization directions of the polarization unit 330 are different, a plurality of polarization directions may be made on the polarization unit 330 under the condition that the receiving surface of the optical signal guided by the light guide layer 310 is kept unchanged, so that the optical signal received by the image acquisition unit 320 includes the optical signal whose receiving surface and polarization directions form different included angles.

Preferably, two directions perpendicular to each other are included in the plurality of polarization directions. Wherein the two polarization directions are perpendicular and parallel to the receiving surface of the optical signal, respectively.

For example, the plurality of polarization directions form a centrosymmetric pattern. The centrosymmetric pattern is, for example, circular or square.

As shown in the plan views of the polarizing plates shown in fig. 16 and 17, the black arrows are projections of the receiving surface of the optical signal on the horizontal plane. It can be seen that the angles between the receiving surface and the respective polarization directions of the polarizers differ. Taking fig. 17 as an example, the plurality of polarization directions of the polarization unit 330 form a circle. Wherein, the polarization direction on the connecting line P1-P2 is vertical to the oblique receiving surface of the optical signal (the included angle is 90 degrees); the polarization direction on the P3-P4 connecting line is parallel to the oblique receiving surface of the optical signal (the included angle is 0 degree); while the other polarization direction is at an angle between 0 and 90 degrees to the receiving surface. It should be understood that the polarization direction in FIG. 17 is the tangential direction of the circle shown, for example, the polarization direction on the line P1-P2 is perpendicular to the line P1-P2, and the polarization direction on the line P3-P4 is parallel to the line P3-P4.

In order to more clearly illustrate the influence of the angle between the receiving surface of the optical signal and the polarization direction on the fingerprint image. First, the principles of 3D fingerprint detection and 2D fingerprint detection are explained with reference to fig. 18 and 19.

Fig. 18 shows fingerprint detection of a 3D fingerprint. Blood and tissue are present within the ridges of the fingerprint of finger 350, and light incident on the ridges is absorbed by the ridges, with less light exiting the ridges. An air gap exists between the valleys of the fingerprint and the display screen 340, so that light incident to the valleys is reflected at the glass-air interface, and thus more light exits from the valleys. So that the fingerprint image acquired based on the reflected light appears as bright valleys and dark ridges. Because this application embodiment carries out fingerprint detection based on oblique light, therefore, the light that the light returns from the finger includes S light and P light after the finger reflection. Assuming that the polarization unit 330 is the polarization unit with circular polarization direction shown in fig. 17, after passing through the light guide layer 310, the receiving surface where the optical signal in the target direction is located is perpendicular to the polarization direction in the P1-P2 direction and parallel to the polarization direction on the connecting line of P3-P4. Since the polarization direction on the connecting line P1-P2 is perpendicular to the receiving surface, S light in the optical signal can pass through the direction, and P light is blocked; and the polarization direction of the connecting line P3-P4 is parallel to the receiving surface, so that in the direction, P light in the optical signal can pass through, and S light is blocked. In the other polarization directions, the components of the transmitted S and P light are gradually changed.

In general, as shown in fig. 19, when the incident angle is smaller than the brewster angle, the energy of S light is larger than the energy of P light in the reflected light. As the incident angle increases, the energy of the S light gradually increases, and the energy of the P light gradually decreases. Wherein the vibration direction of the S light is perpendicular to the receiving surface, and the vibration direction of the P light is parallel to the receiving surface.

Fig. 20 is a fingerprint image obtained using the polarization unit shown in fig. 17. Wherein the polarization direction in the direction of P1-P2 is perpendicular to the receiving surface, so that S light can pass through and P light is blocked; while the polarization direction in the P3-P4 direction is parallel to the receiving surface, so that P light can pass and S light is blocked. But the energy of the S light is greater than the energy of the P light. Therefore, the definition of the fingerprint images in the directions of P1-P2 is obviously higher than that of the fingerprint images in the directions of P3-P4. In other directions, the clarity is between the two.

It can be seen that, for 3D fingerprints, when the included angles between different polarization directions and the oblique receiving surface are different, the components of S-waves and P-waves in the optical signals received by the image acquisition unit in different polarization directions are different, and thus, differences also exist between the definitions of the fingerprint images in different polarization directions.

However, for a 2D fake fingerprint, such as that shown in fig. 21, the 2D fingerprint 360 has no valley and ridge portions, which forge actual valleys and ridges by white and black stripes. The black stripes absorb incident light, and the white stripes reflect the incident light. Since 2D fingerprints are usually carried on rough surfaces such as paper and photos, the reflection of light at white stripes is mainly diffuse reflection, and the reflected light includes substantially no S light and P light. Thus, the energy of the optical signal in each polarization direction is approximate. For a 2D fingerprint, the sharpness of the fingerprint image is the same in all directions.

The reflection at the valley of the 3D fingerprint shown in fig. 18 is an interface reflection, so that the reflected light includes S light and P light, and the definition of the fingerprint image corresponding to the polarization direction through which more S light is transmitted on the polarization unit 330 is higher than that of the fingerprint image corresponding to the polarization direction through which more P light is transmitted. The reflection at the valleys shown in fig. 21 is diffuse reflection, so the reflected light is close to natural light, and the degree of attenuation thereof in each polarization direction is the same, so the sharpness of the corresponding fingerprint image in each polarization direction is approximate. Whether the definition of the fingerprint image in different polarization directions is the same or not can be judged, and whether the fingerprint of the finger is a 3D fingerprint or a 2D fingerprint is judged. When the fingerprint is a forged 2D false fingerprint, the definition of the fingerprint image is more uniform; when the fingerprint is a 3D fingerprint, the definition of the fingerprint image is different in different polarization directions.

In this mode 2, the image capturing unit 320 may include a sensor, such as shown in fig. 1A and 1B; the image acquisition unit 320 may also include a plurality of sensors, such as shown in fig. 2A and 2B.

When the image pickup unit 320 includes a plurality of sensors, the number of the light guide layer 310 is plural. The light guide layers 310 are used for guiding the light signals of the target direction to the sensors, respectively.

When the image capturing unit 320 includes a sensor, a light guiding layer 310 may be disposed over the sensor. The light guide layer 310 is used to guide the light signal in the target direction to the sensor.

Wherein each light guiding layer 310 may be a light guiding layer as described in manner 1.

For example, the light guide layer 310 includes: a microlens array 311 including a plurality of microlenses for condensing the optical signal; and at least one light blocking layer 312 sequentially disposed under the microlens array 311, each light blocking layer including a plurality of openings corresponding to the plurality of microlenses, respectively. And the direction of the connecting line of the openings corresponding to the same microlens in each light blocking layer is the target direction.

For another example, the light guide layer 310 includes an array of light guide channels 313 for guiding the light signal of the target direction to the image capturing unit 320.

The light guide channel array 313 includes a plurality of light guide channels, and the light guide channels are arranged in an inclined manner. Wherein the inclined direction of the light guide channel is the target direction. The light guide channel may be formed of, for example, an air through hole or a light transmitting material.

Alternatively, the light guide channel array 313 includes a plurality of optical fibers, which are vertically arranged. Wherein the optical signal in the target direction is transmitted in the optical fiber based on total reflection.

For another example, the light guide layer 310 includes an optical function film layer 314 for transmitting the light signal in the target direction and blocking the light signal in other directions. The optical function film layer 314 may be, for example, a grating film or a prism film.

It should be understood that the structure of the light guide layer 310 herein can refer to the related description with respect to fig. 5 to 12, and the description is omitted here for brevity.

Optionally, in this embodiment of the present application, the apparatus 300 for fingerprint detection further includes: and the processor is used for determining whether the fingerprint image is a 3D fingerprint image according to the definition of the fingerprint image in different areas.

For example, in the fingerprint image, when the definitions of the areas corresponding to the optical signals of which the receiving surfaces form different included angles with the polarization directions of the polarization units are different, it is determined that the fingerprint is a 3D fingerprint; and/or when the definition of the areas corresponding to the optical signals of which the receiving surfaces form different included angles with the polarization direction in the fingerprint image is the same, determining that the fingerprint is a forged 2D fingerprint.

The processor may be a processor of the terminal device, for example, a master of the terminal device; the processor may also be a processor integrated in the apparatus for streak detection 300. And are not limited herein.

Optionally, in this embodiment of the present application, the apparatus 300 for fingerprint detection further includes: and the filter layer is arranged in a light path between the display screen and the image acquisition unit 320 and is used for filtering optical signals in a non-target waveband so as to transmit the optical signals in the target waveband to the image acquisition unit 320.

Wherein the filter layer is disposed in an optical path between the display screen and the image capturing unit 320. For example, the filter layer is disposed above the light guide layer 310; alternatively, the filter layer may be disposed above the image capturing unit 320, such as the filter layer 370 shown in fig. 5 to 7.

The filter layer may be an independently formed filter layer, for example, a filter layer formed by using blue crystal or blue glass as a carrier; the light path may be formed by coating a film on a surface of any one of the layers, for example, a surface of a pixel, a surface of any one of transparent dielectric layers, or a surface of a microlens, to form a filter layer.

Optionally, in this embodiment of the present application, the apparatus 300 for fingerprint detection further includes: a dielectric and a metal layer, which may include connection circuitry to the pixels.

For example, the dielectric and metal layers may be disposed over the pixels in a Front illuminated (FSI) manner; dielectric and metal layers may also be disposed under the pixels in a Back Side Illumination (BSI) manner.

An embodiment of the present application further provides an electronic device, including: a display screen and the fingerprint detection device 300 in the various embodiments of the present application described above.

The display screen can be a common non-folding display screen, and can also be a folding display screen or a flexible display screen.

By way of example and not limitation, the electronic device in the embodiments of the present application may be a portable or mobile computing device such as a terminal device, a mobile phone, a tablet computer, a notebook computer, a desktop computer, a game device, an in-vehicle electronic device, or a wearable smart device, and other electronic devices such as an electronic database, an automobile, and an Automated Teller Machine (ATM). This wearable smart machine includes that the function is complete, the size is big, can not rely on the smart mobile phone to realize complete or partial function, for example: smart watches or smart glasses and the like, and only focus on a certain type of application function, and need to be used in cooperation with other devices such as smart phones, such as various smart bracelets for physical sign monitoring, smart jewelry and other devices.

It should be noted that, without conflict, the embodiments and/or technical features in the embodiments described in the present application may be arbitrarily combined with each other, and the technical solutions obtained after the combination also fall within the protection scope of the present application.

It should be understood that the specific examples in the embodiments of the present application are for the purpose of promoting a better understanding of the embodiments of the present application, and are not intended to limit the scope of the embodiments of the present application, and that various modifications and variations can be made by those skilled in the art based on the above embodiments and fall within the scope of the present application.

The above description is only for the specific embodiments of the present application, but the scope of the present application is not limited thereto, and any person skilled in the art can easily conceive of the changes or substitutions within the technical scope of the present application, and shall be covered by the scope of the present application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.

Claims

1. The utility model provides a fingerprint detection's device which characterized in that sets up in electronic equipment's display screen below, the device includes:

2. The apparatus of claim 1, wherein the polarization unit comprises a polarization direction, and the light guide layer is configured to guide the light signals in multiple directions to the image capturing unit, wherein angles between receiving surfaces of the light signals in the multiple directions and the polarization direction are different.

3. The apparatus of claim 2, wherein the plurality of directions comprises a first direction and a second direction, wherein the first direction is orthogonal to the polarization direction and the second direction is parallel to the polarization direction.

4. The apparatus according to claim 2, wherein the image capturing unit comprises a plurality of sensors, the number of the light guiding layers is plural, the plurality of light guiding layers respectively correspond to the plurality of directions, and are configured to respectively guide the light signals in the corresponding directions to the plurality of sensors.

5. The apparatus of claim 4, wherein the light guiding layer comprises:

a microlens array including a plurality of microlenses for converging the optical signal;

at least one light blocking layer is sequentially arranged below the microlens array, each light blocking layer comprises a plurality of openings corresponding to the microlenses, and the direction of a connecting line of the openings corresponding to the same microlens in each light blocking layer is the direction corresponding to the light guide layer.

6. The apparatus of claim 4, wherein the light guide layer comprises an array of light guide channels, the array of light guide channels comprising:

the light guide channels are obliquely arranged, and the oblique direction of the light guide channels is the direction corresponding to the light guide layer; or,

the optical fibers are vertically arranged, and optical signals in the direction corresponding to the light guide layer are transmitted in the optical fibers based on total reflection.

7. The apparatus of claim 4, wherein the light guiding layer comprises:

and the optical function film layer is used for transmitting the optical signal in the direction corresponding to the light guide layer and blocking the optical signal in other directions.

8. The apparatus of claim 2, wherein the image capturing unit comprises a sensor, the number of the light guiding layers is one, the light guiding layer comprises a plurality of regions corresponding to the plurality of directions, respectively, and a portion of the light guiding layer located in each region is configured to guide the light signal in the corresponding direction to the sensor.

9. The apparatus of claim 8, wherein the portion of the light guiding layer within each region comprises:

and the light blocking layers are sequentially arranged below the microlens array, each light blocking layer comprises a plurality of openings corresponding to the microlenses, and the direction of a connecting line of the openings corresponding to the same microlens in each light blocking layer is the direction corresponding to the region.

10. The apparatus of claim 8, wherein the portion of the light guiding layer within each region comprises:

the light guide channels are obliquely arranged, and the oblique direction of the light guide channels is the direction corresponding to the region; or,

the optical fibers are vertically arranged, and optical signals in the direction corresponding to the area are transmitted in the optical fibers based on total reflection.

11. The apparatus of claim 8, wherein the portion of the light guiding layer within each region comprises:

and the optical function film layer is used for transmitting the optical signal in the direction corresponding to the region and blocking the optical signal in other directions.

12. The apparatus of claim 1, wherein the polarization unit comprises a plurality of polarization directions, and the light guide layer is configured to guide the optical signal in a target direction to the image capturing unit, wherein angles between a receiving surface of the optical signal in the target direction and the plurality of polarization directions are different.

13. The apparatus of claim 12, wherein the plurality of polarization directions form a centrosymmetric pattern.

14. The device of claim 13, wherein the centrosymmetric pattern is circular or square.

15. The apparatus of claim 12, wherein the image capturing unit comprises a plurality of sensors, the number of the light guiding layers is plural, and the plurality of light guiding layers are configured to guide the light signals in the target direction to the plurality of sensors, respectively.

16. The apparatus of claim 12, wherein the image capturing unit comprises a sensor, the number of the light guiding layers is one, and the light guiding layers are used for guiding the light signal in the target direction to the sensor.

17. The apparatus of claim 15 or 16, wherein the light guiding layer comprises:

and the light blocking layers are sequentially arranged below the microlens array, each light blocking layer comprises a plurality of openings corresponding to the microlenses, and the direction of a connecting line of the openings corresponding to the same microlens in each light blocking layer is the target direction.

18. The apparatus of claim 15 or 16, wherein the light guiding layer comprises an array of light guiding channels, the array of light guiding channels comprising:

the light guide channels are obliquely arranged, and the oblique direction of the light guide channels is the target direction; or,

a plurality of optical fibers, the optical fibers being vertically arranged, the optical signal in the target direction being transmitted in the optical fibers based on total reflection.

19. The apparatus of claim 15 or 16, wherein the light guiding layer comprises an array of light guiding channels, the array of light guiding channels comprising:

and the optical function film layer is used for transmitting the optical signal in the target direction and blocking the optical signal in other directions.

20. The apparatus of any one of claims 1 to 16, wherein the polarizing unit is located within the display screen.

21. The apparatus of any one of claims 1 to 16, wherein the polarizing unit is located above the light guiding layer.

22. The apparatus of claim 21, wherein the polarization unit is formed on the upper surface of the light guide layer or the image capturing unit by a coating film, or the polarization unit is attached to the upper surface of the light guide layer or the image capturing unit by an optical adhesive.

23. The apparatus of any one of claims 1 to 16, further comprising:

and the processor is used for determining whether the fingerprint image is a 3D fingerprint image according to the definition of the fingerprint image in different areas.

24. The apparatus of claim 23, wherein the processor is specifically configured to:

determining that the fingerprint image is a 3D fingerprint image when the definitions of areas corresponding to optical signals of which the receiving surfaces form different included angles with the polarization directions of the polarization units in the fingerprint image are different;

and when the definition is the same, determining that the fingerprint image is not the 3D fingerprint image.

25. The apparatus of any one of claims 1 to 16, further comprising:

and the filter layer is arranged in a light path between the display screen and the image acquisition unit and used for filtering optical signals in a non-target waveband so as to transmit the optical signals in the target waveband to the image acquisition unit.

26. The device of claim 25, wherein the filter layer is disposed over the light guide layer.

27. An electronic device, comprising:

a display screen; and the number of the first and second groups,

an apparatus for fingerprint detection as defined in any one of claims 1 to 26.