CN210109828U - Fingerprint identification device and electronic equipment - Google Patents

Abstract

A fingerprint identification device and an electronic device can improve the performance of fingerprint identification. The device includes: the micro-lens array is arranged between the display screen and the optical fingerprint sensor and comprises a plurality of micro-lenses, the micro-lenses are used for converging inclined optical signals reflected by a finger above the display screen, and the projection of the light-converging surfaces of the micro-lenses on a plane vertical to the optical axis of the micro-lenses is rectangular; at least one light blocking layer arranged between the microlens array and the optical sensing unit of the optical fingerprint sensor, wherein each light blocking layer comprises a plurality of openings corresponding to the plurality of microlenses, and the oblique light signals converged by each microlens pass through the openings corresponding to the microlenses in different light blocking layers and reach the optical sensing unit of the optical fingerprint sensor; and the optical fingerprint sensor is used for detecting the oblique optical signal, and the last light-blocking layer in the at least one light-blocking layer is integrated in the optical fingerprint sensor.

Description

Fingerprint identification device and electronic equipment

This application claims priority from the filing of the chinese patent office on 22/1/2019, PCT application No. PCT/CN2019/072649 entitled "fingerprint recognition device and electronic device", the entire contents of which are incorporated herein by reference.

This application claims priority from the filing of the chinese patent office on 7/3/2019, PCT application No. PCT/CN2019/077370 entitled "fingerprint recognition device and electronic device", 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 identification.

Background

The technology for identifying the fingerprints under the optical screen is characterized in that reflected light formed by reflecting light 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. The performance of fingerprint identification is closely related to the amount of fingerprint information that can be collected by the optical fingerprint sensor, and therefore, how to collect more fingerprint information by the optical fingerprint sensor becomes a problem to be solved.

SUMMERY OF THE UTILITY MODEL

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

In a first aspect, an apparatus for fingerprint identification is provided, and is applied in an electronic device having a display screen, including:

the micro-lens array is arranged between the display screen and the optical fingerprint sensor and comprises a plurality of micro-lenses for converging inclined optical signals reflected by a finger above the display screen, wherein the projection of the light-gathering surfaces of the micro-lenses on a plane perpendicular to the optical axis of the micro-lenses is rectangular;

at least one light blocking layer, disposed between the microlens array and the optical sensing unit of the optical fingerprint sensor, wherein each light blocking layer includes a plurality of openings corresponding to the plurality of microlenses, respectively, and the oblique light signals converged by each microlens pass through the openings corresponding to the microlenses in different light blocking layers to reach the optical sensing unit of the optical fingerprint sensor;

the optical fingerprint sensor is configured to detect the oblique light signal, wherein a last light-blocking layer of the at least one light-blocking layer is integrated in the optical fingerprint sensor.

In one possible implementation, the tilt angle of the tilted optical signal is between 10 ° and 50 °.

In one possible implementation, the light-condensing surface is spherical or aspherical.

In one possible implementation, the curvatures in the respective directions of the light-condensing surface are the same.

In one possible implementation, the apparatus further includes:

a filter layer disposed over the microlens array or between the microlens array and the optical fingerprint sensor, the filter layer configured to transmit optical signals within a particular wavelength range.

In a possible implementation manner, when the filter layer is disposed above the microlens array, an air layer or a transparent adhesive layer is filled between the filter layer and the microlens array.

In a possible implementation manner, the periphery of the transparent adhesive layer is surrounded by the shading material.

In one possible implementation, when the filter layer is disposed between the microlens array and the optical fingerprint sensor, the filter layer is integrated with the optical fingerprint sensor.

In one possible implementation, the microlens array further includes a base material located under the plurality of microlenses, the base material having the same refractive index as a material of the microlenses.

In one possible implementation, the apparatus further includes:

and the at least one light blocking layer is arranged between the micro lens array and the optical sensing unit of the optical fingerprint sensor, each light blocking layer comprises a plurality of openings corresponding to the micro lenses, and the openings corresponding to the same micro lenses in different light blocking layers are used for guiding the inclined light signals converged by the micro lenses to the optical fingerprint sensor in sequence.

In a possible implementation manner, the inclination angle of the connecting line of the openings corresponding to the same microlens in different light blocking layers is the same as the inclination angle of the oblique optical signal.

In one possible implementation, the apertures in different light blocking layers corresponding to the same microlens are sequentially reduced from top to bottom.

In a possible implementation manner, each microlens corresponds to one optical sensing unit of the optical fingerprint sensor, wherein the openings corresponding to the same microlens in different light blocking layers are used for guiding the oblique light signals converged by the microlenses to the optical sensing units corresponding to the microlenses in sequence.

In one possible implementation manner, the connection line of the openings corresponding to the same microlens in different light blocking layers passes through the central area of the optical sensing unit corresponding to the microlens.

In one possible implementation manner, among the other light-blocking layers except the last light-blocking layer in the at least one light-blocking layer, the adjacent light-blocking layers are connected through the transparent medium layer.

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

Based on the technical scheme, the inclined light signals reflected by the finger are guided to the optical fingerprint sensor through the micro-lens array, on one hand, the micro-lens in the micro-lens array is a rectangular micro-lens, and has a better light gathering area ratio compared with a circular lens, so that the optical fingerprint sensor can acquire more fingerprint information, and the fingerprint identification performance is improved; on the other hand, the light intensity of the light signal obliquely incident to the finger after being reflected by the finger is obviously improved, so that the contrast of the fingerprint valley and the ridge can be improved, and the fingerprint identification performance for special fingers such as dry fingers is better.

Drawings

Fig. 1A and 1B are schematic structural views of an electronic device to which the present application is applicable.

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

FIG. 3 is a schematic diagram of fingerprint recognition using vertical light.

Fig. 4 is a schematic diagram of fingerprint recognition using oblique light rays.

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

Fig. 6A is a schematic diagram of a circular microlens array.

Fig. 6B and 6C are schematic diagrams of a rectangular microlens array according to an embodiment of the present application.

Fig. 7 is a schematic diagram of a possible structure of the fingerprint recognition apparatus shown in fig. 5.

Fig. 8 is a schematic diagram of a possible structure of the fingerprint recognition apparatus shown in fig. 5.

Fig. 9 is a schematic diagram of a possible structure of the fingerprint recognition apparatus shown in fig. 5.

Fig. 10 is a schematic diagram of a possible structure of the fingerprint recognition apparatus shown in fig. 5.

Fig. 11 is a schematic diagram of a possible structure of the fingerprint recognition apparatus shown in fig. 5.

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 identification 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 above electronic device, the fingerprint module may be embodied as an optical fingerprint module, which may be disposed in a partial area or a whole area below the display screen, so as to form an Under-screen (Under-display 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 underscreen fingerprint identification technology uses light returned from the top surface of a device display assembly for fingerprint sensing and other sensing operations. The returning light carries information about an object (e.g., a finger) in contact with the top surface, and by collecting and detecting the returning light, a specific optical sensor module located below the display screen is realized. 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 1B show schematic views of an electronic device to which the embodiment of the present application can be applied. Fig. 1 is an orientation diagram of an electronic device 10, and fig. 2 is a partial cross-sectional diagram of the electronic device 10 shown in fig. 1 along a direction a-a'.

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 (which may also be referred to as photosensitive pixels, pixel units, etc.). The sensing array 133 is located in an area or a sensing area thereof, which is the fingerprint detection area 103 (also called a fingerprint collection area, a fingerprint identification area, etc.) of the optical fingerprint module 130. As shown in fig. 1, the fingerprint detection area 103 is located in a display area of the display screen 120. In an alternative embodiment, the optical fingerprint module 130 may be disposed at other positions, such as the side of the display screen 120 or the edge opaque region of the electronic device 10, and the optical path is designed to guide the optical signal from at least a part of the display region of the display screen 120 to the optical fingerprint module 130, so that the fingerprint detection region 103 is actually located in the display region 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, by designing an optical path such as lens imaging, a reflective folded optical path, or other optical path designs such as light converging or reflecting, the area of the fingerprint detection area 103 of the optical fingerprint module 130 may be 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 coincide with the area of the sensing array 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. 1, the optical fingerprint module 130 includes a light detection portion 134 and an optical assembly 132. The light detecting portion 134 includes the sensing array 133 and a reading circuit and other auxiliary circuits electrically connected to the sensing array 133, 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 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 (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 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 133 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 133 of the light detection portion 134 therebelow, so that the sensing array 133 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 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 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 133 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 133. 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, a light blocking layer, etc.) having micro holes (or referred to as open 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 into 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 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 against the fingerprint detection area 103, the display 120 emits a beam of light 111 towards the target finger 140 above the fingerprint detection area 103, and the light 111 is reflected at 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-mentioned reflected light and scattered light are collectively referred to as reflected light for convenience of description. Because the ridges (ridges) 141 and the valleys (valley)142 of the fingerprint have different light reflection capabilities, 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 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 can be further performed, so that an optical fingerprint identification 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 further includes 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.

On the other hand, in some implementation manners, the optical fingerprint module 130 may only include 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 the 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 the user experience to be poor. In other alternative embodiments, the optical fingerprint module 130 may specifically include a plurality of optical fingerprint sensors. A plurality of optics fingerprint sensor can set up side by side through the concatenation mode 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, in the electronic device 10 shown in fig. 2A and 2B, when the optical fingerprint apparatus 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 by, for example, splicing, and the sensing areas of the plurality of optical fingerprint sensors together form the fingerprint detection area 103 of the optical fingerprint apparatus 130.

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 to and disposed 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 (Filter) or other optical film, which may be disposed between the optical path guiding structure and the optical fingerprint sensor or between the display screen 120 and the optical path guiding structure, and is 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 disposed for each optical fingerprint sensor to filter interference light, 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 (Lens), and a small hole formed by a shading material above the optical Lens is 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 respectively configured with an optical lens to perform fingerprint imaging, or the optical fingerprint sensors may also use the same optical lens to achieve 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.

The number, size and arrangement of the fingerprint sensors shown above are only examples and can be adjusted according to actual requirements. For example, the number of the plurality of fingerprint sensors may be 2, 3, 4, or 5, and the like, and the plurality of fingerprint sensors may be distributed in a square or circle, and the like.

The embodiment of the application can be applied to detection of various fingers, and is particularly suitable for detection of dry fingers. By dry finger is meant a relatively dry finger or a relatively clean finger. The scheme that adopts perpendicular light to carry out fingerprint identification at present is not good enough to the fingerprint identification effect of doing the finger, and this application embodiment adopts the scheme that slope light signal carries out fingerprint identification can show the fingerprint identification performance that promotes to doing the finger. The following description is made with reference to fig. 3 and 4.

Fig. 3 and 4 show the OLED display screen 120 and the cover plate 121 over the display screen 120, with a finger over the cover plate 121.

FIG. 3 is a schematic diagram of fingerprint recognition using vertical light. As shown in the left side of fig. 3, when a normal finger is in contact with the display screen, the ridges of the fingerprint are in direct contact with the display screen, dark stripes are formed at the positions of the ridges, and bright stripes are formed at the positions of the valleys. As shown in the right side of fig. 3, when a dry finger is in contact with the display screen, an air gap 310 exists between the ridge of the fingerprint and the display screen, which results in that the ridge of the dry finger can form a "slightly bright" stripe at the position of the ridge of the normal finger compared with the ridge of the dry finger, and the brightness at the position of the valley is unchanged, so that the contrast of the valley and the ridge of the fingerprint is reduced, and the performance of fingerprint identification is affected.

The embodiment of the application adopts the oblique light to carry out fingerprint identification, and figure 4 is a schematic diagram of adopting the oblique light to carry out fingerprint identification. As shown in the left side of fig. 4, when a normal finger is in contact with the display screen, the ridges of the fingerprint are in direct contact with the display screen, dark stripes are formed at the positions of the ridges, and bright stripes are formed at the positions of the valleys. According to the fresnel reflection principle, the reflectivity of vertical light is low, and the reflectivity at the contact interface of a finger and a display screen is generally below 4%. When the fingerprint identification is carried out by adopting the inclined light, the reflectivity can be obviously improved. As shown on the right side of fig. 4, when a dry finger is in contact with the display screen, there is an air gap 310 between the ridge of the fingerprint and the display screen. Since the relative refractive index of the valleys is higher than that of the ridges, when the finger is irradiated with the oblique light, although the intensity of the light reflected by the valleys and the ridges of the fingerprint is increased, the intensity of the light reflected by the valleys is increased more. Thus, the contrast of the valleys and the ridges is improved, thereby improving the performance of fingerprint recognition. When the inclination angle of the obliquely incident oblique light signal is between 10 ° and 50 °, the contrast of the valley and the ridge, i.e., the ratio of the intensity of the valley to the intensity of the ridge, may be improved by 50% to 300%.

The excitation light source of fingerprint identification of this application embodiment can be the luminescence unit of self-luminous display screen such as OLED, and every luminescence unit can send light to each direction, and this application embodiment adopts wherein to be located the light on the incline direction and carries out fingerprint identification. However, the present application is not limited thereto, and a separate light source may be provided for fingerprint recognition, and in this case, the scheme may be applied to a non-self-luminous display screen.

When the light-emitting unit of the OLED screen is used as an excitation light source to perform fingerprint identification, the improvement of the fingerprint signal is limited by the maximum brightness that the OLED screen can provide, and in order to break the bottleneck, the utilization rate of the reflected light of the finger needs to be improved. Therefore, in the embodiment of the present application, a rectangular microlens, or a square lens, is used to replace a conventional circular microlens, so that a higher light-gathering area ratio can be obtained, which can generally reach more than 98%.

Hereinafter, the fingerprint recognition apparatus according to the embodiment of the present application will be described in detail with reference to fig. 5 to 11.

Fig. 5 is a schematic diagram of an apparatus 500 for fingerprint identification according to an embodiment of the present application. The apparatus 500 for fingerprint recognition is applied to an electronic device having a display screen, wherein the apparatus 500 comprises:

a microlens array 510 disposed between the display screen and the optical fingerprint sensor 520, the microlens array including a plurality of microlenses for converging oblique optical signals reflected by a finger above the display screen, a projection of a light-converging surface of the microlens on a plane perpendicular to an optical axis thereof being rectangular;

at least one light blocking layer 550 disposed between the microlens array 510 and the optical sensing unit of the optical fingerprint sensor 520, wherein each light blocking layer includes a plurality of openings corresponding to the plurality of microlenses, respectively, and the oblique light signal converged by each microlens passes through the openings corresponding to the microlenses in different light blocking layers to reach the optical sensing unit of the optical fingerprint sensor 520;

an optical fingerprint sensor 520 for detecting the oblique light signal.

Hereinafter, the microlens projected in a rectangular shape is also referred to as a rectangular microlens.

On one hand, the micro lens in the micro lens array is a rectangular micro lens, and has better light gathering area ratio compared with a circular lens, so that the optical fingerprint sensor can acquire more fingerprint information, and the fingerprint identification performance is improved; on the other hand, the light intensity of the light signal obliquely incident to the finger after being reflected by the finger is obviously improved, so that the contrast of the fingerprint valley and the ridge can be improved, and the fingerprint identification performance for special fingers such as dry fingers is better.

Optionally, the last light-blocking layer of the at least one light-blocking layer 550 is integrated in the optical fingerprint sensor 520.

In this embodiment, the last light-blocking layer is integrated in the optical fingerprint sensor 520, so that the reliability of fingerprint identification can be ensured, the oblique optical signal reflected by the finger can be effectively transmitted to the optical sensing unit of the optical fingerprint sensor, stray light is blocked while the optical signal is guided, and the performance of fingerprint identification is improved.

When the last light-blocking layer is integrated in the optical fingerprint sensor 520, each opening in the last light-blocking layer may be located above a central area of an optical sensing unit of the optical fingerprint sensor 520, for example, so that the oblique optical signal may be received by the optical sensing unit most effectively, thereby ensuring better photoelectric conversion efficiency.

Fig. 6A is a top view of a microlens array composed of conventional circular microlenses, and it can be seen that a gap 620 exists between adjacent microlenses 610, and an optical signal reflected by a finger and entering the gap 620 cannot be collected by the optical fingerprint sensor 520, although this portion of the optical signal also carries fingerprint information, but is not utilized.

Fig. 6B and 6C are a top view and a side view of a microlens array composed of rectangular microlenses according to an embodiment of the present application. The projection of the microlens 511 shown in fig. 6 right below it is a square, also referred to as a square microlens 511. It can be seen that, by closely arranging the rectangular microlenses 511, no gap exists between adjacent microlenses 511, so that a higher light-gathering area ratio can be obtained, more fingerprint information can be obtained, and the fingerprint identification performance can be improved.

The light-gathering surface of the micro lens is a surface for gathering light. The surface type of the light-condensing surface is not limited in this embodiment, and may be, for example, a spherical surface or an aspherical surface. Preferably, the curvatures of the light-condensing surfaces in all directions are the same, so that the imaging focuses of all directions of the micro lens can be at the same position, and the imaging quality is guaranteed.

It should be understood that each microlens in the microlens array 510 in the embodiment of the present application may also have two light-collecting surfaces, the projection areas of the two light-collecting surfaces are both rectangular, and the two light-collecting surfaces are symmetrical and form a shape similar to a convex lens, so as to achieve a better light-collecting effect.

In addition, the microlenses in the microlens array 510 of the embodiment of the present application may be rectangular microlenses, or may be other polygonal microlenses, that is, the forward projection of the microlenses is polygonal, for example, hexagonal. The microlenses need only be closely joined together to eliminate or reduce the gap 620 described above.

Optionally, the microlens array 510 further includes a base material under the plurality of microlenses, and the base material 512 has the same refractive index as the material of the microlenses, thereby reducing light loss due to abrupt changes in refractive index.

Optionally, the apparatus 500 further comprises a filter layer 530, wherein the filter layer 530 is disposed above the microlens array 510 or between the microlens array 510 and the optical fingerprint sensor 520, and the filter layer 530 is configured to transmit optical signals in a specific wavelength range.

For example, when the filter layer 530 is disposed over the microlens array 510, air 531 is between the filter layer 530 and the microlens array 510, or the filter layer 530 is filled with a transparent adhesive layer 532.

The Clear Adhesive layer 532 may be, for example, Optically Clear Adhesive (OCA), Clear glue, or Clear Adhesive film.

The microlens array 510 may be surrounded by a light blocking material 534, for example, black foam, to block light, thereby preventing stray light around the microlens array 510 from entering the microlens array 510 and affecting fingerprint recognition performance.

For another example, when the filter layer 530 is disposed between the microlens array 510 and the optical fingerprint sensor 520, the filter layer 510 is integrated with the optical fingerprint sensor 520.

The embodiment of the present disclosure does not limit the integration manner of the filter layer 510 and the optical fingerprint sensor 520, for example, an evaporation process may be used to perform a film coating on the optical sensing unit of the optical fingerprint sensor 520 to form the filter layer 530, for example, a filter material film is prepared above the optical sensing unit of the optical fingerprint sensor 520 by methods such as atomic layer deposition, sputter coating, electron beam evaporation coating, and ion beam coating. Preferably, the thickness of the filter layer 530 may be 20 μm or less.

Taking fig. 7-9 as an example, a microlens array 510, an optical fingerprint sensor 520, and a filter layer 530 are shown. The optical fingerprint sensor 520 includes a plurality of sensing units and a light blocking layer 551 over the sensing units. The light blocking layer 551 includes a plurality of openings, such as an opening 5511, each opening corresponds to one optical sensing unit, such as the opening 5511 corresponds to the optical sensing unit 521, and the opening 5511 is used for allowing the oblique light signal of a predetermined angle to reach the optical sensing unit 521 corresponding to the opening 5511 and blocking the light of other directions from affecting the oblique light signal. The microlens array 510 is composed of a plurality of microlenses, and the refractive index of the substrate material 512 under the microlens array 510 may be equal to that of the microlenses, for example, so as to reduce light loss caused by abrupt changes in refractive index.

For example, as shown in fig. 7, the filter layer 530 may be disposed over the microlens array 510 with an air gap 531 between it and the microlens array 510. The microlens array 510 is provided with a light blocking material 540 around the periphery thereof.

For example, as shown in fig. 8, the filter layer 530 may be disposed over the microlens array 510 with a transparent glue layer 532 interposed between the microlens array 510. The transparent adhesive layer 532 may be a low refractive index optical adhesive. The transparent adhesive layer 532 is provided with a light shielding material 540 at the periphery.

For example, as shown in fig. 9, the filter layer 530 is integrated with the optical fingerprint sensor 520, and the filter layer 530 is located above the optical sensing unit 521 of the optical fingerprint sensor 520, so that light satisfying the wavelength condition can reach the optical sensing unit 521, and light not satisfying the wavelength condition is filtered out.

The filter layer 530 can filter light in the infrared band and transmit light in the visible band.

In the three implementations of the filter layer 530 shown in fig. 7 to 9, the filter layer 530 is integrated with the optical fingerprint sensor 520 to better ensure the reliability of fingerprint identification, but the present application does not limit the location and type of the filter layer 530.

In the present application, the light signal is tilted for fingerprint identification, and as shown in fig. 7 to 9, the light entering the microlens 511 at the angle i can be converged by the microlens 511 and reach the optical sensing unit 521 through the opening 5511. While the remaining angles of light are blocked by the light blocking layer 551. Compared with vertical reflected light, the light intensity of the inclined light is obviously improved, and the reflected light at the fingerprint valley is improved more than that of the reflected light at the fingerprint ridge, so that the contrast ratio of the fingerprint valley and the fingerprint ridge is increased, and the fingerprint identification performance is improved.

The openings in each light blocking layer can effectively prevent light crosstalk and block stray light except for realizing light path guiding, so that only light rays meeting the preset angle i can pass through the light blocking layer to reach the optical fingerprint sensor 520.

The number of light blocking layers is not limited in the embodiments of the present application. Too many light blocking layers can increase the thickness and complexity of the fingerprint identification device, and too few light blocking layers can bring more interference light and influence the imaging effect. When in actual use, a reasonable number of light blocking layers can be arranged according to requirements.

For example, fig. 7 to 9 show the case where only one light-blocking layer, that is, the light-blocking layer 551, is present.

For another example, fig. 10 shows a case where two light-blocking layers are present. Fig. 10 adds a light-blocking layer 552 on the basis of fig. 9, and a transparent dielectric layer 561 is filled between the light-blocking layer 552 and the filter layer 530. Other relevant components in fig. 10 may be referred to in the description of fig. 9.

For another example, fig. 11 shows a case where three light-blocking layers are present. Fig. 11 is added with a light-blocking layer 552 and a light-blocking layer 553 on the basis of fig. 9, and a transparent medium layer 561 is filled between the light-blocking layer 552 and the light-blocking layer 553, and a transparent medium layer 562 is filled between the light-blocking layer 553 and the filter layer 530. Other relevant components in fig. 11 may be referred to in the description of fig. 9.

Further, optionally, the inclination angle of the connecting line of the openings corresponding to the same microlens in different light blocking layers is the same as the inclination angle of the inclined optical signal.

Because the light rays obliquely incident to the fingers are still oblique light rays after being reflected by the fingers, in order to transmit the oblique light rays reflected by the fingers, the oblique light path is adopted in the embodiment of the application. Therefore, there should be a lateral offset between the apertures in different light-blocking layers corresponding to the same microlens, and the connection lines of these apertures in different light-blocking layers should pass through the corresponding optical sensing unit, so that the oblique optical signal can reach the optical sensing unit.

The lateral distances between two openings corresponding to the same microlens and respectively located in two adjacent light blocking layers can be equal or unequal.

And, the vertical distance between two adjacent light blocking layers may also be equal or unequal.

For example, when the vertical distances between two adjacent light-blocking layers are equal, the lateral distances between the openings corresponding to the same microlens in the two adjacent light-blocking layers are also equal.

Optionally, each microlens corresponds to an optical sensing unit of the optical fingerprint sensor 520, wherein the openings corresponding to the same microlens in different light blocking layers are used for guiding the oblique light signal converged by the microlens to the optical sensing unit corresponding to the microlens in sequence.

Further, optionally, a connection line of the openings corresponding to the same microlens in different light blocking layers passes through a central region of the optical sensing unit corresponding to the microlens.

For example, the opening of the last light-blocking layer may be disposed above the center of the corresponding optical sensing unit to ensure that the oblique optical signal can reach the central area of the optical sensing unit, thereby achieving better photoelectric conversion efficiency.

For example, as shown in fig. 11, light reaching the microlens 511 at an angle i passes through the opening 5521 in the light blocking layer 552, the opening 5531 in the light blocking layer 553, and the opening 5511 in the light blocking layer 551 carried by the optical fingerprint sensor 520 in sequence, and finally reaches the optical sensing unit 521. The opening 5531 is shifted to the left by a certain distance relative to the opening 5521, the opening 5511 is shifted to the left by a certain distance relative to the opening 5531, and a central connection line of the opening 5521, the opening 5531 and the opening 5511 can pass through the corresponding optical sensing unit 521, so that the guiding of the oblique light can be realized.

Since the micro-lens has a converging effect on light, the more downward the light is transmitted, the narrower the angle of the light beam formed by converging the light beam. Therefore, optionally, the apertures of the openings corresponding to the same microlenses in different light blocking layers are sequentially reduced from top to bottom, so that the light beam reaching the optical fingerprint sensor 520 is a narrow light beam, narrow-angle reception of the light beam is realized, the light beam which is not needed can be effectively attenuated while the collimation degree is ensured, and the definition of the optical fingerprint image collected by the optical fingerprint sensor 520 is further improved. For example, as shown in fig. 11, the apertures of the opening 5521, the opening 5531, and the opening 5511 corresponding to the same microlens 511 are sequentially reduced.

In fig. 10 and 11, the last light blocking layer reached by the oblique light signal is integrated in the optical fingerprint sensor 520, so that the reliability of fingerprint recognition is ensured, and adjacent light blocking layers among the remaining light blocking layers may be connected through a transparent dielectric layer. For example, in FIG. 11, the light blocking layer 551 is integrated into the optical fingerprint sensor 520, the light blocking layer 552 and the light blocking layer 553 are connected by a transparent dielectric layer 561, and the light blocking layer 553 and the filter layer 530 are connected by a transparent dielectric layer 562. Preferably, the refractive indexes of the transparent medium layers 561 and 562 may be the same as the refractive index of the substrate material 512 of the microlens array 510 and the refractive index of the microlens array 510, so as to reduce light loss caused by abrupt change of the refractive index.

However, the application is not limited to this, and other methods may be used to connect and fix the light-blocking layer. For example, the light blocking layer is fixed by a mechanical structure such as a bracket, or a plurality of light blocking layers are pasted together by transparent glue or an adhesive film.

The embodiment of the present application further provides an electronic device, which includes the fingerprint identification apparatus in the various embodiments of the present application.

Optionally, the electronic device further includes a display screen, which may be a common non-foldable 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 (16)

1. An apparatus for fingerprint identification, applied in an electronic device having a display screen, comprising:

the micro-lens array is arranged between the display screen and the optical fingerprint sensor and comprises a plurality of micro-lenses for converging inclined optical signals reflected by a finger above the display screen, wherein the projection of the light-gathering surfaces of the micro-lenses on a plane perpendicular to the optical axis of the micro-lenses is rectangular;

at least one light blocking layer, disposed between the microlens array and the optical sensing unit of the optical fingerprint sensor, wherein each light blocking layer includes a plurality of openings corresponding to the plurality of microlenses, respectively, and the oblique light signals converged by each microlens pass through the openings corresponding to the microlenses in different light blocking layers to reach the optical sensing unit of the optical fingerprint sensor;

the optical fingerprint sensor is configured to detect the oblique light signal, wherein a last light-blocking layer of the at least one light-blocking layer is integrated in the optical fingerprint sensor.

2. The apparatus of claim 1, wherein the oblique angle of the oblique optical signal is between 10 ° and 50 °.

3. The apparatus of claim 1 or 2, wherein the light collection surface is spherical or aspherical.

4. The apparatus of claim 1 or 2, wherein the curvatures in the respective directions of the light-condensing surfaces are the same.

5. The apparatus of claim 1 or 2, wherein the microlenses are rectangular microlenses.

6. The apparatus of claim 1 or 2, further comprising:

a filter layer disposed over the microlens array or between the microlens array and the optical fingerprint sensor, the filter layer configured to transmit optical signals within a particular wavelength range.

7. The device of claim 6, wherein the filter layer is disposed over the microlens array with an air layer or a transparent glue layer between the filter layer and the microlens array.

8. The device of claim 7, wherein the transparent adhesive layer is surrounded by a light blocking material.

9. The apparatus of claim 6, wherein the filter layer is integrated with the optical fingerprint sensor when the filter layer is disposed between the microlens array and the optical fingerprint sensor.

10. The apparatus of claim 1 or 2, wherein the microlens array further comprises a base material underlying the plurality of microlenses, the base material having the same refractive index as the material of the microlenses.

11. The device according to claim 1 or 2, wherein the connection line of the openings corresponding to the same microlens in different light-blocking layers has the same inclination angle as the inclination angle of the tilted optical signal.

12. The device according to claim 1 or 2, wherein the apertures in different light-blocking layers corresponding to the same microlens are sequentially reduced in aperture from top to bottom.

13. The apparatus according to claim 1 or 2, wherein each of the microlenses corresponds to one optical sensing unit of the optical fingerprint sensor, and wherein the openings corresponding to the same microlenses in different light-blocking layers are used for sequentially guiding the oblique light signals converged by the microlenses to the optical sensing units corresponding to the microlenses.

14. The apparatus according to claim 13, wherein the connection lines of the openings corresponding to the same microlens in different light blocking layers pass through the central region of the optical sensing unit corresponding to the microlens.

15. The device according to claim 14, wherein the adjacent light-blocking layers are connected by a transparent medium layer in the other light-blocking layers except the last light-blocking layer in the at least one light-blocking layer.

16. An electronic device, characterized in that it comprises an apparatus for fingerprint recognition according to any one of claims 1 to 15.

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