CN110062931B

CN110062931B - Fingerprint identification device, fingerprint identification method and electronic equipment

Info

Publication number: CN110062931B
Application number: CN201980000376.3A
Authority: CN
Inventors: 姚国峰; 沈健
Original assignee: Shenzhen Goodix Technology Co Ltd
Current assignee: Shenzhen Goodix Technology Co Ltd
Priority date: 2019-03-12
Filing date: 2019-03-12
Publication date: 2021-07-16
Anticipated expiration: 2039-03-12
Also published as: CN110062931A; WO2020181489A1

Abstract

Provided are a fingerprint identification device and a fingerprint identification method, which can improve fingerprint identification performance. The device includes: the optical path guiding structure is arranged below the display screen and used for guiding inclined optical signals with a specific angle, which are reflected from a finger when the finger is irradiated from a pressing area of the display screen, to a sensing unit, which is positioned below a first area of the display screen, in the image acquisition module, wherein the first area is positioned in a non-pressing area of the display screen; the image acquisition module is arranged below the light path guide structure and used for acquiring the fingerprint image of the finger according to the inclined light signal.

Description

Fingerprint identification device, fingerprint identification method and electronic equipment

Technical Field

The present application relates to the field of information technology, and more particularly, to a fingerprint identification apparatus, a fingerprint identification method, and an electronic device.

Background

The technology for identifying the fingerprints under the optical screen is characterized in that reflected light formed by reflecting light rays emitted by a light source on a finger is collected, and the reflected light carries fingerprint information of the finger, so that the identification of the fingerprints under the screen is realized. For a special finger, for example, a relatively dry finger, an air gap exists between the valley of the fingerprint and the display screen, and the air gap can cause serious diffuse scattering of light, so that the reflection difference of the ridge and the valley of the fingerprint on the light is influenced, the contrast of a fingerprint image obtained based on reflected light imaging can be reduced, and the performance of fingerprint identification is influenced.

Disclosure of Invention

The embodiment of the application provides a fingerprint identification device, a fingerprint identification method and electronic equipment, which can improve fingerprint identification performance.

In a first aspect, a fingerprint identification device is provided, which includes: the optical path guiding structure is arranged below the display screen and used for guiding inclined optical signals with a specific angle, which are reflected from a finger when the finger is irradiated from a pressing area of the display screen, to a sensing unit, which is positioned below a first area of the display screen, in the image acquisition module, wherein the first area is positioned in a non-pressing area of the display screen; the image acquisition module is arranged below the light path guide structure and used for acquiring the fingerprint image of the finger according to the inclined light signal.

In one possible implementation, the optical path guiding structure is further configured to: guiding a vertical light signal reflected from a finger when the finger is irradiated from the pressing area to a sensing unit positioned below the pressing area in the image acquisition module; wherein the image acquisition module is configured to: and if the fingerprint image is failed to be acquired according to the vertical light signal, acquiring the fingerprint image according to the inclined light signal.

In a possible implementation manner, an exposure time used by the image acquisition module to acquire the oblique light signal is longer than an exposure time used to acquire the vertical light signal.

In one possible implementation, the optical path guiding structure includes: a microlens array in which a microlens located below the pressing region is used to converge the vertical light signal, and a microlens located below the first region is used to converge the oblique light signal; and the light blocking layer is arranged below the microlens array and comprises a plurality of openings corresponding to the microlenses respectively, wherein each opening is used for guiding the light signals converged by the corresponding microlens to the image acquisition module.

In one possible implementation, the apparatus further includes a processing module, configured to: acquiring information of the pressing area and the first area, wherein the distance between the pressing area and the first area is determined according to the following information: the height from the display screen to the image acquisition module, the distance between adjacent holes in the light blocking layer and the focal length of the micro lens.

In one possible implementation manner, a distance between the pressing region and the first region is d, and d is h × s/f, where h is a height between the display screen and the image capturing module, s is a distance between adjacent openings in the light blocking layer, and f is a focal length of the microlens.

In one possible implementation, the first area is located within a shaded area within the non-depressed area that is covered by and not in contact with the finger.

In one possible implementation, the area of the first region is equal to the area of the pressing region.

In one possible implementation, the image acquisition module is formed by splicing a plurality of optical fingerprint sensors.

In one possible implementation, the image acquisition module comprises an optical fingerprint sensor.

In a second aspect, a fingerprint identification method is provided, where the method is performed by a fingerprint identification device, where the device includes an optical path guiding structure and an image acquisition module, which are sequentially disposed below a display screen, and the method includes: the optical path guiding structure guides an inclined optical signal with a specific angle, which is reflected from a finger when the finger is irradiated from a pressing area of the display screen, to a sensing unit in the image acquisition module, which is positioned below a first area of the display screen, wherein the first area is positioned in a non-pressing area of the display screen; and the image acquisition module acquires the fingerprint image of the finger according to the inclined light signal.

In one possible implementation, the method further includes: the optical path guiding junction guides a vertical optical signal reflected from a finger when the finger is irradiated from the pressing area to a sensing unit positioned below the pressing area in the image acquisition module; wherein, the image acquisition module obtains the fingerprint image of the finger according to the oblique light signal, including: and if the image acquisition module fails to acquire the fingerprint image according to the vertical light signal, acquiring the fingerprint image according to the inclined light signal.

In a possible implementation manner, the fingerprint identification apparatus further includes a processing module, and the processing module is configured to: acquiring information of the pressing area and the first area, wherein the distance between the pressing area and the first area is determined according to the following information: the height from the display screen to the image acquisition module, the distance between adjacent holes in the light blocking layer and the focal length of the micro lens.

In a third aspect, a terminal device is provided, which includes the fingerprint identification apparatus in the first aspect or any possible implementation manner of the first aspect.

Based on the technical scheme, the light path guide structure in the fingerprint identification device can guide the light source to irradiate the finger in the finger pressing area and the inclined light signal reflected by the finger to the sensing unit positioned below the specific area in the finger non-pressing area in the image acquisition module, so that the image acquisition module acquires the fingerprint image of the finger according to the inclined light signal. Because the diffuse reflection intensity of the oblique light generated by the finger removing is lower than that of the vertical light, the contrast of the collected fingerprint image can be improved and the fingerprint detection performance can be improved for special fingers which are easy to generate diffuse reflection in the fingerprint identification process, such as dry fingers.

Drawings

Fig. 1 is a schematic structural diagram of an electronic device to which the present application is applicable.

Fig. 2 is a schematic structural diagram of a fingerprint recognition device adopting a multi-sensor splicing mode.

Fig. 3 is a schematic diagram of a normal finger when performing fingerprint detection.

Fig. 4 is a schematic illustration of a dry finger when performing fingerprint detection.

Fig. 5 is a schematic block diagram of a fingerprint identification device according to an embodiment of the present application.

Fig. 6 is a schematic diagram of the fingerprint recognition according to the embodiment of the present application.

Fig. 7 is a schematic diagram of the fingerprint recognition according to the embodiment of the present application.

Fig. 8 is a schematic configuration diagram of an optical path guiding structure of an embodiment of the present application.

Fig. 9 is a schematic flowchart of a fingerprint identification method according to an embodiment of the present application.

Fig. 10 is a schematic flow chart of a specific implementation manner of the fingerprint identification method according to the embodiment of the application.

Fig. 11 is a schematic block diagram of an electronic device of an embodiment of the present application.

Detailed Description

The technical solutions in the embodiments of 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 optical fingerprint systems, including but not limited to optical fingerprint identification systems and medical diagnostic products based on optical fingerprint imaging, and the embodiments of the present application are only described by way of example, but should not be construed as limiting the embodiments of the present application, and the embodiments of the present application are also applicable to other systems using optical imaging technology, etc.

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 terminal devices with display screens; more specifically, in the terminal device described above, the fingerprint recognition device may be embodied as an optical fingerprint device, which may be disposed in a partial area or an entire area below the display screen, thereby forming an Under-display or Under-screen optical fingerprint system. Alternatively, the fingerprint identification device may be partially or completely integrated into the display screen of the terminal device, so as to form an In-display or In-screen optical fingerprint system.

As shown in fig. 1, which is a schematic structural diagram of a terminal device to which the embodiment of the present application is applicable, the terminal device 10 includes a display screen 120 and an optical fingerprint device 130, where the optical fingerprint device 130 is disposed in a local area below the display screen 120. The optical fingerprint device 130 comprises an optical fingerprint sensor comprising a sensing array 133 having a plurality of optical sensing elements 131. The area where the sensing array is located or the sensing area thereof is the fingerprint acquisition area 121 of the optical fingerprint device 130. As shown in fig. 1, the fingerprint acquisition area 121 is located in the display area of the display screen 120. In an alternative embodiment, the optical fingerprint device 130 may be disposed at other positions, such as the side of the display screen 120 or the edge opaque area of the terminal device 10, and the optical path is designed to guide the optical signal of at least a part of the display area of the display screen 120 to the optical fingerprint device 130, so that the fingerprint collection area 121 is actually located in the display area of the display screen 120. In an alternative embodiment, the optical fingerprint device 130 may be disposed at other positions, such as the side of the display screen 120 or the edge opaque area of the terminal device 10, and the optical signal of at least a part of the display area of the display screen 120 is guided to the optical fingerprint device 130 through the optical path design, so that the fingerprint collection area 121 is actually located in the display area of the display screen 120.

It should be understood that the area of the fingerprint acquisition area 121 may be different from the area of the sensing array of the optical fingerprint device 130, for example, by the design of optical path such as lens imaging, reflective folded optical path design or other light converging or reflecting optical path design, the area of the fingerprint acquisition area 121 of the optical fingerprint device 130 may be larger than the area of the sensing array of the optical fingerprint device 130. In other alternative implementations, the fingerprint acquisition area 121 of the optical fingerprint device 130 may be designed to substantially coincide with the area of the sensing array of the optical fingerprint device 130 if optical path guidance is performed, for example, by light collimation.

Therefore, when the user needs to unlock the terminal device or perform other fingerprint verification, the user only needs to press a finger on the fingerprint collection area 121 of the display screen 120, so as to realize fingerprint input. Since fingerprint detection can be implemented in the screen, the terminal 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 basically extended to the front surface of the whole terminal device 10.

In one implementation, as shown in FIG. 1, the optical fingerprint device 130 includes a light detection portion 134 and an optical assembly 132. The light detecting portion 134 includes the sensing array and the reading circuit and other auxiliary circuits electrically connected to the sensing array, which can be fabricated on a chip (Die) by a semiconductor process, such as an optical imaging chip or an optical fingerprint sensor. The sensing array is specifically a Photo detector (Photo detector) array, which includes a plurality of Photo detectors distributed in an array, and the Photo detectors can be used as the optical sensing units. The optical assembly 132 may be disposed above the sensing array 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 for optical 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.

For example, the light guide layer may specifically be a Collimator (collimater) layer manufactured on a semiconductor silicon wafer, and the collimater unit may specifically be a small hole, and in reflected light reflected from a finger, light perpendicularly incident to the collimater unit may pass through and be received by an optical sensing unit below the collimater unit, and light with an excessively large incident angle is attenuated by multiple reflections inside the collimater unit, so that each optical sensing unit can basically only receive reflected light reflected from a fingerprint pattern directly above the optical sensing unit, and the sensing array can detect a fingerprint image of the finger.

In another implementation, the light guide layer or the light path guiding structure may also be an optical Lens (Lens) layer, which has one or more Lens units, such as a Lens group composed of one or more aspheric lenses, and is used to converge the reflected light reflected from the finger to the sensing array of the light detecting portion 134 therebelow, so that the sensing array may perform imaging based on the reflected light, thereby obtaining the fingerprint image of the finger. Optionally, the optical lens layer may further form a pinhole in the optical path of the lens unit, and the pinhole may cooperate with the optical lens layer to enlarge the field of view of the optical fingerprint device, so as to improve the fingerprint imaging effect of the optical fingerprint device 130.

In other implementations, the light guide layer or the light path guiding structure 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 of the light detecting 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. And other optical film layers, such as a dielectric layer or a passivation layer, can be formed between the microlens layer and the sensing unit. More specifically, a light blocking layer (or referred to as a light shielding layer) 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 guiding layer or the light path guiding structure 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 device 130 may use the display unit (i.e., the OLED light source) of the OLED display screen 120 located in the fingerprint acquisition area 121 as an excitation light source for optical fingerprint detection. When the finger 140 is pressed against the fingerprint collection area 121, the display 120 emits a beam of light 111 toward the target finger 140 above the fingerprint collection area 121, and the light 111 is reflected on the surface of the finger 140 to form reflected light or scattered light by the inside of the finger 140 to form scattered light. Because the ridges (ridges) 141 and the valleys (valley)142 of the fingerprint have different light reflection capacities, the reflected light 151 from the ridges and the reflected light 152 from the valleys of the fingerprint 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 device 130 and converted into corresponding electrical signals, i.e., fingerprint detection signals; based on the fingerprint detection signal, fingerprint image data can be obtained, and fingerprint matching verification can be further performed, so that an optical fingerprint identification function is realized in the terminal device 10.

In other implementations, the optical fingerprint device 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 device 130 may be adapted for use with a non-self-emissive display such as a liquid crystal display or other passively emissive display. Taking an application to a liquid crystal display having a backlight module and a liquid crystal panel as an example, to support the underscreen fingerprint detection of the liquid crystal display, the optical fingerprint system of the terminal 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 or in an edge area below a protective cover of the terminal device 10, and the optical fingerprint device 130 may be disposed below the edge area of the liquid crystal panel or the protective cover and guided through a light path so that the fingerprint detection light may reach the optical fingerprint device 130; alternatively, the optical fingerprint device 130 may be disposed below the backlight module, and the backlight module may be perforated or otherwise optically designed to allow the fingerprint detection light to pass through the liquid crystal panel and the backlight module and reach the optical fingerprint device 130. When the optical fingerprint device 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 understood that in a specific implementation, the terminal device 10 further includes a transparent protective cover plate, which may be a glass cover plate or a sapphire cover plate, positioned above the display screen 120 and covering the front surface of the terminal 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.

In some embodiments, the optical fingerprint device 130 may include only one optical fingerprint sensor, where the area of the fingerprint acquisition area 121 of the optical fingerprint device 130 is small and the position is fixed, so that a user needs to press a finger to a specific position of the fingerprint acquisition area 121 when performing fingerprint input, otherwise the optical fingerprint device 130 may not acquire a fingerprint image and the user experience is poor.

In other embodiments, the optical fingerprint device 130 may specifically include a plurality of optical fingerprint sensors. The plurality of optical fingerprint sensors may be disposed side by side below the display screen 120 in a splicing manner, and sensing areas of the plurality of optical fingerprint sensors jointly form a fingerprint collecting area 121 of the optical fingerprint device 130. That is to say, the fingerprint collection area 121 of the optical fingerprint device 130 may include a plurality of sub-areas, each of which corresponds to the sensing area of one of the optical fingerprint sensors, respectively, so as to extend the fingerprint collection area 121 of the optical fingerprint module 130 to the main area of the lower half portion of the display screen, that is, to the area that the finger presses conventionally, thereby realizing the blind-touch type fingerprint input operation. Alternatively, when the number of optical fingerprint sensors is sufficient, the fingerprint acquisition area 130 may also be extended to half or even the entire display area, thereby enabling half-screen or full-screen fingerprint detection.

Fig. 2 is a schematic diagram of the optical fingerprint device 130 including 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 acquisition area 121 of the optical fingerprint device 130. That is, the fingerprint acquisition area 121 of the optical fingerprint device 130 may include a plurality of sub-areas, each of which corresponds to one of the optical fingerprint sensors, or each of which corresponds to a sensing area of one of the optical sensing arrays 133.

Optionally, corresponding to a plurality of optical fingerprint sensors of the optical fingerprint apparatus 130, there may be a plurality of optical path guiding structures in the optical component 132, where each optical path guiding structure corresponds to one optical fingerprint sensor, and is attached above the corresponding optical fingerprint sensor. Alternatively, the plurality of optical fingerprint sensors may share an integral optical path directing structure, i.e. the optical path directing structure has an area large enough 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 layer or other optical film, which may be between the optical path guiding structure and the optical fingerprint sensor or between the display screen 120 and the optical path guiding structure, and mainly used for isolating the influence of external interference light on the optical fingerprint detection. The optical filter may be configured to filter ambient light that penetrates through a finger and enters the optical fingerprint sensors through the display screen 120, and similar to the optical path guiding structure, the optical filter may be respectively configured to filter interference light for each optical fingerprint sensor, or may also cover the plurality of optical fingerprint sensors simultaneously with one large-area optical filter.

The light path modulator can also be replaced by an optical 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 also 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.

In the embodiment of the present application, the optical fingerprint device may also be referred to as an optical fingerprint recognition device, a fingerprint recognition device, etc.; the optical detection part can also be called an image acquisition module, an image sensor, an optical fingerprint sensor and the like; the fingerprint acquisition area of the image acquisition module can also be called a fingerprint identification area, a fingerprint detection area, an induction area of the image acquisition module and the like; the optical path guiding structure may also be referred to as an angle screening structure, an angle screening component, etc.; the sensing unit may also be referred to as a light sensing unit, an optical sensing unit, etc.; the sensing array may also be referred to as a sensing cell array, a photosensing unit array, etc.

The embodiment of the application can be applied to detection of various fingers, and is particularly suitable for detection of dry fingers. The term "dry finger" means a relatively dry finger or a relatively clean finger, for example, a finger immediately after washing the hand or a finger immediately after getting up, and the fat or oil secretion content of the surface of the finger is low. When the dry finger contacts the display screen, the gap (namely the valley of the fingerprint) of the part of the finger contacting the display screen causes serious diffuse reflection of light due to the existence of a large amount of air, so that the effective optical signal which is acquired by the image acquisition module and carries the fingerprint information is interfered by the diffuse reflection light, the contrast of the acquired fingerprint image is poor, and effective fingerprint matching is difficult to perform.

This is explained in detail with reference to fig. 3 and 4. Fig. 3 shows fingerprint recognition of a normal finger, when the finger 140 is in contact with the display screen 120, due to grease existing in the valleys of the finger, normal reflected light signals 151 and 152 are formed on the ridges 141 and the valleys 142 of the fingerprint when the incident light 111 is incident on the finger 140, respectively, and an image of the fingerprint imaged according to the reflected light signals 151 and 152 is shown as 30 in fig. 3. In fig. 4, the finger 140 is a dry finger, and when the finger 140 contacts the display screen 120, the valley 142 of the fingerprint forms diffuse reflection light 152a due to the presence of a large amount of air, so as to affect the contrast of the fingerprint image collected by the image collecting module 130, and the fingerprint image imaged according to the reflection light signals 151 and 152a is shown as 40 in fig. 4. It can be seen that the fingerprint image 40 is significantly less sharp than the fingerprint image 30 due to the diffuse reflection effect caused at the valleys 142 of the fingerprint in fig. 4.

In order to solve the problem existing in the fingerprint identification of the dry finger, the fingerprint image of the finger is collected by using the inclined optical signal in the embodiment of the application. Namely, the image acquisition module acquires an optical signal obliquely incident to the finger and reflected by the finger, and acquires a fingerprint image of the finger according to the oblique optical signal. This is because light rays incident at a large angle have a lower diffuse reflection intensity than light rays incident at a small angle.

An example in life is taken as an illustration. When scanning the two-dimensional code of the shared bicycle at night, if the mobile phone is directly opposite to the two-dimensional code for scanning, a flash lamp of the mobile phone can cause serious reflection, and the effect is a diffuse reflection effect. In this time, the mobile phone is only required to be properly inclined, and the light emitted by the flash lamp obliquely irradiates the two-dimensional code, so that a relatively clear two-dimensional code pattern can be scanned.

The embodiment of the application provides a fingerprint identification scheme, and the fingerprint image of a finger is acquired by collecting the inclined light signal reflected by the finger, so that the fingerprint identification performance of the finger, such as a dry finger, is improved.

Fig. 5 is a schematic block diagram of a fingerprint identification device 500 according to an embodiment of the present application. The fingerprint acquisition area of the device 500 is located within the display screen. As shown in fig. 5, the apparatus 500 includes an optical path directing structure 510 and an image acquisition module 520.

The optical path guiding structure 510 is disposed under the display screen, and is configured to guide an oblique optical signal having a specific angle, which is reflected from a finger when the finger is irradiated from a pressed region of the display screen, to a sensing unit in the image capturing module 520, which is located under a first region of the display screen, which is located in a non-pressed region of the display screen.

The image capturing module 520 is disposed under the optical path guiding structure 510, and is configured to capture a fingerprint image of the finger according to the oblique optical signal.

The "pressing area" here is a pressing area when a finger performs a fingerprint recognition operation within a fingerprint collection area of the image collection module 520 located within the display screen; the "non-pressed area" is an area within the fingerprint acquisition area other than the pressed area.

The first region is located within the non-compression region. For example, preferably, the first region is located in a shadow region covered by the finger and not in contact with the finger in the non-pressed region.

The area of the first region and the area of the pressing region may be equal or unequal.

The term "under the pressing region" may mean, for example, directly under the pressing region. The term "under the first region" may mean, for example, directly under the first region. But allows a certain degree of offset which does not have a significant impact on the acquisition of the fingerprint image.

It should be noted that there is a distance d between the first area and the collection area, which is related to the specific angle θ of the oblique light signal reflected by the finger. Generally, if the first region is located in the shadow region under the finger, the first region and the acquisition region do not overlap. However, in some special cases, such as when the specific angle θ is small, there may be an overlap between the first region and the pressing region. The specific angle θ is determined by the internal configuration parameters of the fingerprint recognition device 500, which will be further described below.

Hereinafter, the specific angle is also referred to as a tilt angle.

The image capturing module 520 may be composed of at least one optical fingerprint sensor, for example, in a multi-sensor splicing manner as shown in fig. 2, spliced into 2 × 3, 2 × 4, or 3 × 3 optical fingerprint sensor arrays, where each optical fingerprint sensor includes an array of sensing units, and each sensing array includes a plurality of sensing units. That is, the image capturing module 520 is formed by splicing a plurality of optical fingerprint sensors with smaller areas.

The image capturing module 520 may also be formed by an optical fingerprint sensor, which may include one sensing unit array or a plurality of sensing unit arrays, wherein each sensing unit array includes a plurality of sensing units. That is, the image capture module 520 may be a single large area optical fingerprint sensor.

The light source irradiates the finger in the pressing area of the finger, and the oblique light signal reflected by the finger is transmitted to the image capturing module 520 through the light path guiding structure 510. The sensing unit under the first region in the image capturing module 520 captures the oblique light signal, thereby acquiring a fingerprint image. The diffuse reflection intensity of the oblique light on the finger is lower than that of the vertical light. Therefore, for special fingers which are easy to generate diffuse reflection in the fingerprint identification process, such as dry fingers, the contrast of the acquired fingerprint image can be improved, and the fingerprint detection performance is improved.

The image capturing module 520 of the embodiment of the present application has a large fingerprint capturing area, which can cover the pressing area and the first area of the finger. The finger can perform a pressing operation at any position in the fingerprint acquisition area for fingerprint identification.

The image capturing module 520 may be a Complementary Metal Oxide Semiconductor (CMOS), a Charge-coupled Device (CCD), a Thin Film Transistor (TFT), an avalanche diode, etc., which is not limited in this embodiment.

The display screen in the embodiment of the present application may adopt various display screens described above, such as an LCD display screen or an OLED display screen. When the display screen is an OLED display screen, the light-emitting layer of the display screen includes a plurality of organic light-emitting diode light sources, and the fingerprint identification device 500 uses at least some of the organic light-emitting diode light sources as excitation light sources for fingerprint identification.

Optionally, when a finger performs a pressing operation within the fingerprint acquisition area, a portion of the luminescent layer located within the pressing area emits light. That is, the light source irradiates the finger only in the pressed region, and does not emit light in the non-pressed region.

On one hand, the whole large-area fingerprint acquisition area does not need to emit light, so that the power consumption of the display screen can be reduced; on the other hand, the light from the non-pressed area without carrying fingerprint information can be prevented from interfering the oblique light signal collected by the image collecting module 520.

Optionally, the optical path guiding structure 510 may be further configured to guide a vertical optical signal reflected from a finger when the finger is irradiated from within the pressing area to a sensing unit located below the pressing area in the image capturing module 520.

Optionally, the vertical light signal may be first collected by a sensing unit located below the pressing area in the image collecting module 520, and a fingerprint image of the finger may be obtained according to the vertical light signal. If the fingerprint image acquisition according to the vertical light signal fails, for example, when the fingerprint image definition cannot achieve fingerprint matching, the sensing unit located below the first area in the image acquisition module 520 acquires an oblique light signal with a specific angle, and acquires the fingerprint image according to the oblique light signal.

Since the intensity of the oblique light signal is lower than that of the vertical light signal, the responsivity of the sensing unit of the image capturing module 520 to the oblique light signal is reduced, and the exposure time needs to be appropriately extended to ensure sufficient signal output. Therefore, optionally, the exposure time for the image capturing module 520 to capture the oblique light signal may be longer than the exposure time for capturing the vertical light signal.

In one implementation, the optical path directing structure 510 may include a microlens array 511 and a light blocking layer 512 disposed below the microlens array 511.

In the microlens array 511, a microlens located under the pressing area is used to condense a vertical light signal reflected by the finger, and a microlens located under the first area is used to condense a tilted light signal of a specific angle reflected by the finger.

The light blocking layer 512 includes a plurality of openings corresponding to the plurality of microlenses, wherein each opening is used for guiding the light signal converged by its corresponding microlens to the image capturing module 520.

The light blocking layer 512 is disposed at the back focal plane of the microlens array 511. Each opening in the light blocking layer 512 may be disposed at a focal point of the corresponding microlens, so as to filter out stray light and realize screening of light rays in a specific direction.

The aperture corresponding to the same microlens for directing a vertical optical signal may be a different aperture than the aperture corresponding to the microlens for directing a tilted optical signal. For example, the corresponding opening of the microlens located below the pressing region is located at the focal point thereof, i.e., the opening corresponding to the microlens is located right below the microlens; and the aperture corresponding to the microlens located under the first region is located at the focal point of the adjacent lens, i.e. the aperture corresponding to the microlens is located obliquely below the microlens.

The image capturing module 520 includes a plurality of sensing units, and optionally, each sensing unit may correspond to a microlens for receiving the light signal converged by the microlens.

The inclination angle θ of the oblique optical signal that can be collected by the sensing unit located below the first region in the image collection module 520 is determined by the structural parameters of the optical path guiding structure and the image collection module. For example, the angle θ is the reflection angle of the finger reflecting light, and is determined by the distance between adjacent openings in the light blocking layer 512 and the focal length of the micro-lenses.

The principle of fingerprint recognition according to the embodiment of the present application will be described in detail below by taking fig. 6 and 7 as an example.

As shown in fig. 6 and 7, the fingerprint collection area 121 in the display screen 120 includes a pressed area 1211 of the finger and a non-pressed area including a first area 1212, and the first area 1212 is located in a shaded area covered by the finger and not contacted in the non-pressed area. This is because in the area outside the finger shadow area, the sensing unit in the image capturing module 520 is very prone to signal saturation under the irradiation of ambient light, such as sunlight, light, etc., thereby causing blooming (blooming) phenomenon and reducing the quality of the captured fingerprint image. While the portion of the finger 140 not in contact with the display screen 120 may just act as a shield against ambient light.

As shown in fig. 6, the sensing unit of the image capturing module 520 located under the pressing area 1211 is used for capturing the vertical light signal reflected by the finger, and the sensing unit of the image capturing module 520 located under the first area 1212 is used for capturing the oblique light signal reflected by the finger.

Only the reflected light rays of the finger are shown in fig. 6, and the incident light information is not shown. The light emitting unit located in the finger-pressed area emits light. The emitted incident light rays may include light rays directed in various directions. The reflected light obtained after reflection by the finger includes a vertically reflected light and an inclined light reflected at a specific angle.

The light path guiding structure 510 under the display screen 120 includes a microlens array 511 and a light blocking layer 512, the center of any opening in the light blocking layer 512 is located at the focus of the corresponding microlens, and light incident outside the opening cannot pass through the light blocking layer 512.

Take the opening 5121 and the opening 5122 as an example. According to the convergence principle of the convex lens, only the light rays incident under the pressing area 1211 in a perpendicular incidence or near collimation manner can be converged at the focal point of the micro lens 5111 and pass through the corresponding opening 5121 to be received by the sensing unit under the pressing area 1211. Light rays incident under the first region 1212 at a specific angle θ may converge at a focal point of the microlens 5112 and pass through the corresponding aperture 5122 to be received by the sensing unit under the first region 1212.

An image capturing module 520 is disposed below the optical path guiding structure 510, and the image capturing module 520 includes a plurality of sensing units 521. Wherein, when imaging is performed according to the vertical light signal, the sensing unit located below the pressing region 1211 operates; when imaging is performed according to the oblique light signal, the sensing unit located below the first region 1212 operates. This can reduce the power consumption of the image acquisition module.

Of course, it can also work with all the sensing units that hold the image capturing module 520. At this time, when the collected light signal is processed, the vertical light signal collected by the sensing unit under the pressing area 1211 may be processed to obtain a fingerprint image, and when the fingerprint image is unclear, the oblique light signal collected by the sensing unit under the first area 1212 may be processed to obtain a fingerprint image.

The light emitting unit in the light emitting layer 123 in fig. 6 below the pressing area 1211 emits light, the light irradiates a portion of the finger 140 in the pressing area 1211, and the vertical light signal 161 reflected by the finger 140 from the pressing area is incident on a portion of the microlens in the microlens array 511 below the pressing area 1211, and is collected by the light sensing unit 521 in the image collecting module 520 below the pressing area 1211 after being converged by the portion of the microlens. The vertical light signal 161 carries fingerprint information of a finger, so that a fingerprint image of the finger can be acquired according to the vertical light signal 161 to perform fingerprint matching. However, the vertical light signal 161 can be affected by severe diffuse reflection. Therefore, for a particular finger, such as a dry finger, a clear fingerprint image may not be acquired, resulting in a fingerprint recognition failure.

At this time, the photosensitive unit 521 in the image capturing module 520 below the first region 1212 is turned on, and still the light emitting unit in the light emitting layer 123 below the pressing region 1211 emits light, the light irradiates the portion of the finger 140 in the pressing region 1211, and the oblique light signal 162 reflected from the pressing region by the finger 140 is incident on the portion of the microlens in the microlens array 511 below the first region 1212, and is collected by the photosensitive unit 521 in the image capturing module 520 below the first region 1212 after being converged by the portion of the microlens. The oblique optical signal 162 carries fingerprint information of the finger, so that a fingerprint image of the finger can be acquired according to the oblique optical signal 162 to perform fingerprint matching. Since the oblique light signal 162 is less affected by the diffused reflection light, a clear fingerprint image can be obtained.

The touch control module (also referred to as a touch layer or touch screen) 122 in fig. 6 may be used to determine the location of the pressed area 1211 of the finger 140 and the location of the shaded area of the finger 140. The position of the first region 1212 can thus be determined within the shaded region according to the relationship that is satisfied between the pressing region 1211 and the first region 1212.

The touch layer 122 may be integrated in the display screen 120 or may be a separate component from the display screen 120. The touch layer 122 may be a capacitive touch based on the principle of sensing the change of an electric field on the surface of the display screen to detect the position of a finger; or may be an infrared touch based on whether infrared rays are blocked by a finger to locate the position of the finger, which is not limited herein.

Optionally, the processing module 530 may obtain information of a pressing area and a first area, wherein a distance between the pressing area and the first area is determined according to the following information: the height from the display screen to the image capture module 520, the distance between adjacent apertures in the light blocking layer, and the focal length of the microlenses.

It is understood that the processing module 530 may be a processing module in a device to which the apparatus 500 is applied, such as a master of a terminal device. Alternatively, the processing module 530 may be integrated with the fingerprint recognition device 500 as a part of the fingerprint recognition device 500, i.e., the processing module 530 is included in the fingerprint recognition device.

The distance between the pressing area and the first area may be determined, for example, by the following formula: d is h × s/f.

Wherein, d is the distance between pressing area and the first region, and h is the display screen extremely height between the image acquisition module, s is distance (pitch) between the adjacent trompil in the light blocking layer, and f is the focus of microlens.

Still taking fig. 6 as an example, under the first region 1212, the distance between the opening 5122 and the adjacent opening on the left side thereof is s, and the focal length of the corresponding microlens 5112 is f, and it can be seen that tan θ is s/f. The angle θ of the oblique optical signal collected by the image collection module 520 is determined by the structural parameters of the optical path guiding structure.

In addition, the size of the openings in the light barrier layer determines the screening ability for the angle of the light. The smaller the opening size, the greater the screening ability for angles.

To illustrate how the distance between the pressing area and the first area is determined, the fingerprint recognition device shown in fig. 6 is simplified to that shown in fig. 8 for illustration.

Fig. 8 shows the display screen 120 and the fingerprint recognition device 500, wherein, based on fig. 7, it can be known that the tilt angle θ of the tilt light signal collected by the fingerprint recognition device 500 should satisfy tan θ ═ s/f. As shown in fig. 8, the angle θ also satisfies tan θ ═ h/d. Therefore, the expression "s/f" can be used to indicate "h/d", and "hs/f". That is, the distance d between the first region 1212 and the pressing region 1211 is hs/f.

Since the touch layer 122 can acquire the entire position of the finger above the fingerprint collection area and the position of the pressing area 1211 of the finger. Thus, the position of the first region 1212 can be determined from the orientation of the shaded region of the finger on the fingerprint acquisition region and the distance d between the first region 1212 and the pressing region 1211. Therefore, when fingerprint identification fails according to the vertical optical signal reflected by the finger, fingerprint identification can be carried out according to the inclined optical signal with the angle theta reflected by the finger.

The effect of diffuse reflection of the oblique light signal due to the angle theta is smaller than that of the perpendicular light signal. Therefore, for a finger which is easy to cause diffuse reflection, such as a dry finger, for a special finger, the fingerprint information of the finger is collected by adopting the inclined optical signal of the angle theta, and a clearer fingerprint image can be obtained.

It should be noted that, due to the difference in refractive index, refraction of light may occur between the display 120 and the contact interface of the fingerprint recognition device 500, which is not shown in fig. 8. In this case, the calculated distance of the first region from the pressed region may deviate from d ═ hs/f calculated when no refraction occurs. However, when the deflection angle is small, the influence on the distance is negligible, and it can be considered that a slight shift in the position of the first region 1212 does not affect the acquisition of the fingerprint image. The location of the first region 1212 may be determined using d ═ hs/f at this time. In practical use, this difference in refractive index can be reduced by using suitable materials. In the embodiments of the present application, it is assumed that the refractive index difference is small enough not to affect the acquisition of the fingerprint image.

The display 120 and the fingerprint recognition device 500 are shown attached together in fig. 6 and 8. In practical applications, there may be a certain gap between the display screen 120 and the fingerprint recognition device 500, such as an air gap, for the optical path transmission. For example, the fingerprint recognition device 500 may be fixed below the display screen 120 through a middle frame of the mobile phone, and be spaced apart from the display screen 120. The installation position of the fingerprint recognition device 500 shown in fig. 6 and 8 is merely illustrative and should not limit the scope of the embodiments of the present application.

Fig. 9 is a schematic flow chart diagram of a fingerprint identification method 900 according to an embodiment of the application. The method shown in fig. 9 may be performed by the fingerprint recognition device 500 described above. The fingerprint recognition device 500 includes a light path directing structure 510 and an image acquisition module 520. The fingerprint acquisition area of the fingerprint identification device 500 is located within the display screen. Wherein the method 900 comprises:

at 910, the optical path guiding structure 510 guides an oblique optical signal having a specific angle, which is reflected from a finger when the finger is irradiated from a pressing area of the display screen, to a sensing unit located below a first area of the display screen in the image capturing module 520.

Wherein the first region is located within a non-pressing region of the display screen;

at 920, the image capture module 520 obtains a fingerprint image of the finger according to the captured oblique light signal.

The light source irradiates the finger in the finger pressing area and guides the inclined light signal reflected by the finger to the image acquisition module, and the image acquisition module acquires a fingerprint image of the finger according to the inclined light signal. Because the diffuse reflection intensity of the oblique light generated by the finger removing is lower than that of the vertical light, the contrast of the collected fingerprint image can be improved and the fingerprint detection performance can be improved for special fingers which are easy to generate diffuse reflection in the fingerprint identification process, such as dry fingers.

For a detailed description of the fingerprint recognition device 500 for performing the method 900, reference may be made to the device-side description, and for brevity, the description is not repeated here.

Optionally, the method further comprises: the optical path guiding structure 510 guides a vertical optical signal reflected from a finger when the finger is irradiated from the pressing area to a sensing unit located below the pressing area in the image capturing module 520. In 920, if the image capturing module 520 fails to capture the fingerprint image according to the vertical light signal, the fingerprint image is captured according to the oblique light signal.

Specifically, the sensing unit located below the pressing area in the image capturing module 520 may be controlled to operate first, and the vertical light signal reflected from the finger when the finger is irradiated from the pressing area may be captured. The image capture module 520 obtains a fingerprint image according to the vertical light signal. If the definition of the fingerprint image obtained by vertical light signal imaging is poor, the fingerprint image is difficult to be matched with the fingerprint template in the fingerprint library. Then, the sensing unit located below the first region in the image capturing module 520 is controlled to operate, and the oblique light signal having a specific angle reflected from the finger when the finger is irradiated from the pressed region is captured. Because the diffuse reflection intensity of the oblique light on the finger is lower than that of the vertical light, the fingerprint image obtained by imaging according to the oblique light signal is clearer.

Since the intensity of the oblique light signal is lower than that of the vertical light signal, the image capturing module 520 requires a longer exposure time to capture the oblique light signal than to capture the vertical light signal. Therefore, in the embodiment, the fingerprint image is collected according to the vertical light signal, and the fingerprint image can be efficiently acquired. And when no clear fingerprint image is acquired, the fingerprint image is acquired according to the oblique light signal. Therefore, the efficiency and the effect of fingerprint identification are considered, and the user experience is improved.

Alternatively, the optical path guiding structure 510 of the embodiment of the present application may include a microlens array 511 and a light blocking layer 512 disposed below the microlens array 511.

Optionally, the processing module 530 is configured to: acquiring information of the pressing area and the first area, wherein the distance between the pressing area and the first area is determined according to the following information: the height from the display screen to the image capture module 520, the distance s between adjacent apertures in the light blocking layer, and the focal length f of the microlenses.

The processing module 530 may be a processing module in a device to which the apparatus 500 is applied, such as a master of a terminal device. Alternatively, the processing module 530 may be integrated with the fingerprint recognition device 500 as a part of the fingerprint recognition device 500.

For example, the processing module 530 may acquire information of a pressing area of the finger on the display screen and information of the overall orientation of the finger from the touch screen. When the image capturing module 520 cannot obtain a clear fingerprint image according to the captured vertical optical signal, the processing module 530 calculates a distance d between the pressing region and the first region according to a formula d ═ h × s/f, where h is a height between the display screen and the image capturing module 520, s is a distance between adjacent holes in the light blocking layer, and f is a focal length of the microlens. And according to the distance d and the information of the overall direction of the finger reported by the touch screen, the position of the first area can be calculated. The first area is located in the shadow area of the finger, and the distance between the first area and the pressing area is d. Preferably, the area of the first region is equal to the area of the pressing region.

For an explanation of the principle of calculating the distance d between the pressing area and the first area, reference may be made to the foregoing descriptions of fig. 6 to 8, and for brevity, no further description is provided here.

A specific implementation of the fingerprint identification method according to the embodiment of the present application is described in detail below with reference to fig. 10. The method can be executed by a terminal device, and the terminal device can include the fingerprint identification device, a display screen, a touch screen, a processing module and the like. Here, an OLED display screen is taken as an example. As shown in fig. 10, the method includes:

step 1001, fingerprint recognition begins.

The finger performs a pressing operation within a fingerprint acquisition area within the display screen.

Step 1002, the touch screen detects a pressing area of a finger and an overall position of the finger.

The touch screen acquires a pressing area of the finger and the overall position of the finger, and a shadow area of the finger can be determined based on the overall position of the finger.

Step 1003, the light-emitting units in the pressing area in the display screen emit light.

And light-emitting units positioned in the fingerprint acquisition area in the display screen are all excitation light sources for fingerprint identification. However, in step 1003, only the light-emitting units in the display screen within the pressing area emit light, so that the finger is illuminated only within the pressing area.

The optical signal reflected by the finger includes a vertical optical signal and a tilted optical signal with a specific angle.

In step 1004, the image capture module captures vertical light signals reflected by the finger for a standard exposure time.

At this time, the sensing unit located below the pressing area in the image acquisition module works to acquire the vertical light signal reflected by the finger and obtain the fingerprint image of the finger in the pressing area based on the vertical light signal.

In step 1005, the processing module determines whether the fingerprint image is clear.

If the definition of the fingerprint image does not meet the requirement, executing step 1006; if the definition of the fingerprint image meets the requirement, step 1007 is executed.

In step 1006, the image capture module captures the oblique light signal with a specific angle reflected by the finger with a long exposure time.

At this time, the sensing unit located below the first area in the image acquisition module works to acquire the inclined light signal reflected by the finger and obtain the fingerprint image of the finger in the pressing area based on the inclined light signal.

Wherein the position of the first region may be determined by the processing module according to the position of the pressing region, the position of the shadow region, and a distance between the pressing region and the first region. The distance between the pressing area and the first area can be determined, for example, from d — h × s/f. After the processing module acquires the position of the first area, the sensing unit positioned below the first area in the image acquisition module can be controlled to be started, so that the inclined light signals are acquired.

Step 1007, the processing module matches the fingerprint image.

The processing module matches the fingerprint image of the finger in the pressing area with the fingerprint information which is input in advance according to a fingerprint algorithm.

In step 1008, the processing module determines whether the matching is successful.

If the match is successful, go to step 1009; if the match fails, step 1010 is performed.

Step 1009, pass the fingerprint authentication.

At step 1010, the fingerprint authentication fails.

For example, the user may be prompted to reattempt or deny access.

Because the fingerprint identification device has a large-area fingerprint acquisition area, the part of the fingerprint identification device, which is positioned below the shadow area of the finger, can acquire the inclined light signal reflected by the finger, and the interference of the ambient light to the inclined light signal is reduced by means of the shadow formed by the finger above the fingerprint acquisition area, so that the performance of the fingerprint identification device is improved, and the user experience is increased.

An electronic device is further provided in the embodiments of the present application, and fig. 11 is a schematic block diagram of an electronic device 1100 in the embodiments of the present application. The electronic device 1100 includes a touch screen 1110, a display 1120, a fingerprint recognition device 1130, and a processing module 1140.

The fingerprint device 1130 may be the fingerprint device described in any of the embodiments of the present application.

The display screen may be the display screen described above, such as an OLED display screen. The light emitting layer of the OLED display includes a plurality of light emitting units, wherein the fingerprint recognition device 1130 uses at least some of the light emitting units as an excitation light source for fingerprint recognition.

The processing module 1140 is communicatively coupled to the touch screen 1110, the display screen 1120, and the fingerprint recognition device 1130, respectively, to perform data and command transmission.

The touch screen 1110, the display screen 1120, the fingerprint identification device 1130, and the processing module 1140 can jointly complete the fingerprint identification method in the embodiment of the present application.

For example, taking fig. 10 as an example, step 1002 is mainly performed by touch screen 1110 and processing module 1140; step 1003 is mainly executed by the display 1120 and the processing module 1140; the remaining steps are primarily performed by the fingerprinting device 1130 and the processing module 1140.

By way of example and not limitation, the electronic device may be a portable or mobile computing device such as a terminal device, a mobile phone, a tablet computer, a laptop computer, a desktop computer, a gaming device, an in-vehicle electronic device, or a wearable smart device, 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 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.

Claims

1. A fingerprint recognition device, comprising:

the light path guiding structure is arranged below the display screen and comprises a micro lens array and a light blocking layer, the micro lens array comprises a plurality of micro lenses, the light blocking layer comprises a plurality of openings respectively corresponding to the micro lenses, and the openings are used for guiding optical signals converged by the micro lenses corresponding to the openings to the image acquisition module;

the image acquisition module is arranged below the light path guide structure and comprises a plurality of sensing units, each sensing unit corresponds to one microlens and is used for receiving optical signals converged by the corresponding microlens;

the fingerprint acquisition area of the fingerprint identification device comprises a pressing area of a finger on the display screen and a non-pressing area with a first area, wherein the first area is located in a shadow area which is covered by the finger but is not contacted with the finger in the non-pressing area, in the light path guiding structure, an opening of a light blocking layer corresponding to a microlens below the pressing area is located at the focus of the microlens, and an opening of a light blocking layer corresponding to a microlens below the first area is located at the focus of an adjacent microlens;

the fingerprint identification device is used for utilizing a self-luminous display unit of the pressing area as an excitation light source for optical fingerprint identification, wherein a part of micro-lenses positioned below the first area are used for guiding inclined light signals with a specific angle reflected from the finger when the finger is irradiated from the pressing area to a sensing unit positioned below the first area in the image acquisition module; the part of the micro lens positioned below the pressing area is used for guiding the vertical light signal reflected from the finger to a sensing unit positioned below the pressing area in the image acquisition module;

the image acquisition module is used for acquiring a fingerprint image of the finger according to the vertical light signal received by the sensing unit positioned below the pressing area, and acquiring the fingerprint image of the finger according to the inclined light signal received by the sensing unit positioned below the first area when the fingerprint image of the finger is failed to be acquired according to the vertical light signal.

2. The apparatus of claim 1, wherein an exposure time used by the image capture module to capture the oblique light signal is greater than an exposure time used to capture the vertical light signal.

3. The apparatus of claim 1 or 2, further comprising a processing module to:

acquiring information of the pressing area and the first area, wherein the distance between the pressing area and the first area is determined according to the following information:

the height from the display screen to the image acquisition module, the distance between adjacent holes in the light blocking layer and the focal length of the micro lens.

4. The device according to claim 3, wherein a distance between the pressing region and the first region is d, and d is h × s/f, where h is a height from the display screen to the image capture module, s is a distance between adjacent openings in the light blocking layer, and f is a focal length of the microlens.

5. A device according to claim 1 or 2, wherein the area of the first region is equal to the area of the pressing region.

6. The apparatus of claim 1 or 2, wherein the image capture module is formed by a plurality of optical fingerprint sensors in a tiled arrangement.

7. The apparatus of claim 1 or 2, wherein the image capture module comprises an optical fingerprint sensor.

8. A fingerprint identification method is characterized in that the method is executed by a fingerprint identification device, the device comprises an optical path guiding structure and an image acquisition module which are arranged below a display screen in sequence, the optical path guiding structure comprises a microlens array and a light blocking layer, the microlens array comprises a plurality of microlenses, the light blocking layer comprises a plurality of openings which are respectively corresponding to the microlenses, the openings are used for guiding optical signals converged by the corresponding microlenses to the image acquisition module, the image acquisition module comprises a plurality of sensing units, each sensing unit corresponds to one microlens and is used for receiving the optical signals converged by the corresponding microlens, the fingerprint acquisition area of the fingerprint identification device comprises a pressing area of a finger on the display screen and a non-pressing area with a first area, and the first area is located in a shadow area which is covered by the finger but is not in contact with the finger in the non-pressing area, and, in the optical path guiding structure, the aperture of the light-blocking layer corresponding to the microlens under the pressing region is located at the focal point of the microlens, and the aperture of the light-blocking layer corresponding to the microlens under the first region is located at the focal point of the adjacent microlens, the fingerprint identification device being configured to use the self-luminous display unit of the pressing region as an excitation light source for optical fingerprint identification, the method comprising:

a part of the micro-lenses located below the pressing area guides a vertical light signal reflected from the finger when the finger is irradiated from the pressing area to a sensing unit located below the pressing area in the image capturing module, and a part of the micro-lenses located below the first area guides an oblique light signal having a specific angle reflected from the finger when the finger is irradiated from the pressing area to a sensing unit located below the first area in the image capturing module;

the image acquisition module acquires the fingerprint image of the finger according to the vertical light signal, and acquires the fingerprint image of the finger according to the inclined light signal when the acquisition of the fingerprint image according to the vertical light signal fails.

9. The method of claim 8, wherein an exposure time used by the image capture module to capture the oblique light signal is greater than an exposure time used to capture the vertical light signal.

10. The method according to claim 8 or 9, wherein the fingerprint recognition device further comprises a processing module configured to:

11. The method according to claim 10, wherein a distance between the pressing region and the first region is d, and d is h × s/f, where h is a height from the display screen to the image capture module, s is a distance between adjacent openings in the light blocking layer, and f is a focal length of a microlens.

12. The method according to claim 8 or 9, characterized in that the area of the first region is equal to the area of the pressing region.

13. The method of claim 8 or 9, wherein the image acquisition module is formed by stitching a plurality of optical fingerprint sensors.

14. The method of claim 8 or 9, wherein the image capture module comprises an optical fingerprint sensor.

15. An electronic device, characterized in that it comprises a display screen and a fingerprint recognition device according to any one of claims 1 to 7.