CN111095287B

CN111095287B - Optical fingerprint device and electronic equipment

Info

Publication number: CN111095287B
Application number: CN201980004322.4A
Authority: CN
Inventors: 纪登鑫; 沈健; 姚国峰
Original assignee: Shenzhen Goodix Technology Co Ltd
Current assignee: Shenzhen Goodix Technology Co Ltd
Priority date: 2019-08-08
Filing date: 2019-08-30
Publication date: 2023-09-12
Anticipated expiration: 2039-08-30
Also published as: CN111095287A

Abstract

An optical fingerprint device and an electronic apparatus, the optical fingerprint device being configured to be disposed below a display screen of the electronic apparatus, comprising: the incident angle conversion structure is arranged below the display screen and is used for converting a first optical signal returned from a finger above the display screen into a second optical signal, wherein the first optical signal is an optical signal inclined relative to the display screen, and the second optical signal is an optical signal vertical to the display screen; the optical component is arranged below the incidence angle conversion structure and is used for receiving the second optical signal and transmitting the second optical signal to the optical sensor; the optical sensor comprises a plurality of optical sensing units, is arranged below the optical assembly and is used for receiving optical signals transmitted by the optical assembly, and the optical signals are used for acquiring fingerprint information of the finger.

Description

Optical fingerprint device and electronic equipment

The present application claims priority from PCT patent application filed by chinese patent office, application number PCT/CN2019/099822, application name "fingerprint detection device and electronic device", 8/2019, the entire contents of which are incorporated herein by reference.

Technical Field

The embodiment of the application relates to the technical field of optical fingerprints, in particular to an optical fingerprint device and electronic equipment.

Background

With the rapid development of the terminal industry, the biometric technology is more and more paid attention to, and more convenient on-screen biometric technology, such as the practical application of the on-screen optical fingerprint identification technology, is required by the public.

The under-screen optical fingerprint identification technology is to set an optical fingerprint module under a display screen, and realize fingerprint identification by collecting optical fingerprint images. With the development of terminal products, the requirements on fingerprint identification performance are higher and higher. Therefore, how to improve the fingerprint recognition performance becomes a technical problem to be solved.

Disclosure of Invention

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

In a first aspect, an optical fingerprint apparatus is provided, configured to be disposed below a display screen of an electronic device, including: the incident light conversion structure is arranged below the display screen and is used for converting a first light signal returned from a finger above the display screen into a second light signal, wherein the first light signal is an inclined light signal relative to the display screen, and the second light signal is a vertical light signal relative to the display screen; the optical component is arranged below the incident light conversion structure and is used for receiving the second optical signal and transmitting the second optical signal to the optical sensor; the optical sensor comprises a plurality of optical sensing units, is arranged below the optical assembly and is used for receiving optical signals transmitted by the optical assembly, and the optical signals are used for acquiring fingerprint information of the finger.

In some possible implementations, the incident light conversion structure includes a micro-prism array including a plurality of micro-prism units, each micro-prism unit including at least one micro-prism, each micro-prism including at least one first incident face and at least one first exit face, the first incident face being inclined with respect to a plane of the display screen, the first exit face being parallel to the plane of the display screen.

In some possible implementations, each of the microprism units includes a microprism, and an optical sensing unit or a column of optical sensing units is disposed below the microprism; or (b)

Each micro-prism unit comprises a plurality of micro-prisms which are distributed in a central symmetry mode, wherein a plurality of optical sensing units are arranged below the micro-prisms.

In some possible implementations, the directions of the incident planes of the plurality of microprisms are different with respect to the optical sensor plane.

In some possible implementations, the plurality of microprisms includes four microprisms, the entrance faces of adjacent ones of the four microprisms being 90 degrees apart from the direction angle of the optical sensor.

In some possible implementations, the first optical signal forms a first angle with a direction perpendicular to the optical sensorThe first incident surface and the first emergent surface of each microprism form a second included angle theta, wherein the first included angle +.>The second included angle theta, the refractive index n of the propagation medium of the first optical signal ₁ Refractive index n of the microprism ₂ The following relationship is satisfied:

in some possible implementations, each of the microprisms includes at least one first support surface provided with a reflective layer.

In some possible implementations, the first optical signal is incident on the first incident surface and enters the microprism to form a third optical signal, the third optical signal is incident on the first incident surface again after being reflected by the first supporting surface, and forms the second optical signal which is emitted vertically after being reflected again by the first incident surface, wherein the first optical signal forms a first included angle with a direction perpendicular to the optical sensorThe first incident surface and the first emergent surface of each microprism form a second included angle theta, the third optical signal forms a third included angle alpha with the direction vertical to the first incident surface, and the third optical signal forms a fourth included angle beta with the direction parallel to the first emergent surface, wherein the first included angle- >The second included angle theta, the third included angle alpha, the fourth included angle beta, the refractive index n of the propagation medium of the first optical signal ₁ Refractive index n of the microprism ₂ The following relationship is satisfied:

β＝(90°-θ)+α

θ＝(90°-θ)+β。

in some possible implementations, the optical fingerprint device further includes:

the light-transmitting coating is arranged on the incident surface of the incident light conversion structure and comprises at least one second incident surface and at least one second emergent surface, wherein the first optical signal enters the light-transmitting coating from the second incident surface to form a fourth optical signal, the fourth optical signal exits from the second emergent surface and enters the incident light conversion structure, and the fourth optical signal is converted into the second optical signal which exits vertically through the incident light conversion structure.

The light-transmitting coating with high refractive index is arranged on the incident surface of the incident light conversion structure, so that a first light signal returned from a finger is converted into a light signal which is emitted vertically after being refracted twice, on one hand, the direction of incident light can be converted, on the other hand, the light signal which is right opposite to the incident surface of the incident light conversion structure is refracted at the air/light-transmitting coating interface and then converted into a vertical light signal, finally the vertical light signal reaches the optical sensor, on the other hand, the light-transmitting coating with high refractive index is adopted, and the required inclined angle of the incident light conversion structure is smaller under the condition of the same incident angle, so that the thickness of the incident light conversion structure is reduced, and the integral thickness of the optical fingerprint device is reduced.

In some possible implementations, the second exit surface is parallel to the incident surface of the incident light conversion structure, the second incident surface is parallel to the exit surface of the incident light conversion structure, and the first optical signal forms a first angle with a direction perpendicular to the second incident surfaceThe incident surface of the incident light conversion structure and the emergent surface of the incident light conversion structure form a second included angle theta, and the fourth optical signal and the direction perpendicular to the incident surface of the incident light conversion structure form a third included angle alpha, wherein the first included angle>The second included angle theta, the third included angle alpha and the refractive index n of the light-transmitting coating ₀ Refractive index n of the propagation medium of the first optical signal ₁ And refractive index n of the microprism ₂ The following relationship is satisfied:

n ₁ sinα＝n ₂ sinθ。

in some possible implementations, the light-transmitting coating is prepared on the incident surface of the incident light conversion structure by spin coating or spray coating.

In some possible implementations, the at least one second incident surface of the light-transmissive coating is provided with an anti-reflection coating for reducing the reflectivity of the first optical signal at the at least one second incident surface and/or a polarization coating for selecting the polarization direction of the first optical signal.

In some possible implementations, the optical assembly includes at least one light blocking layer and a microlens array, the at least one light blocking layer disposed below the microlens array, each of the at least one light blocking layer having an aperture disposed therein;

the micro lens array is used for transmitting the received second optical signal to the optical sensor through the opening in the at least one light blocking layer.

In some possible implementations, the at least one light blocking layer includes a first light blocking layer therein, the first light blocking layer being disposed at a back focal plane position of the microlens array.

In some possible implementations, the first light blocking layer is a metal layer of the optical sensor.

In some possible implementations, the optical assembly further includes:

a filter provided at least one of the following positions:

the incident light conversion structure and the microlens array;

between the microlens array and the optical sensor.

In some possible implementations, the optical assembly includes a straight-hole collimator including a plurality of straight holes, each optical sensing unit in the optical sensor corresponds to at least one of the straight-hole collimators, wherein the straight-hole collimator is configured to receive the second optical signal converted by the incident light conversion structure and transmit the second optical signal to the plurality of optical sensing units through the collimating holes in the straight-hole collimator.

In some possible implementations, the straight hole collimation unit is formed by a metal layer and a metal via layer of the optical sensing unit.

In some possible implementations, the optical assembly further includes:

a filter provided at least one of the following positions:

the incident light conversion structure is arranged between the straight hole collimator and the light source;

the straight hole collimator is arranged between the optical sensing unit and the straight hole collimator.

In some possible implementations, the display screen is an organic light emitting diode OLED display screen, and the optical fingerprint device uses a portion of a display unit of the OLED display screen as an excitation light source for optical fingerprint detection.

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

a display screen;

and the optical fingerprint device of the first aspect or any possible implementation manner of the first aspect, wherein the optical fingerprint device is disposed below the display screen.

In some possible implementations, the display screen is an organic light emitting diode OLED display screen, the display screen including a plurality of OLED light sources, wherein the optical fingerprint device employs at least a portion of the OLED light sources as excitation light sources for optical fingerprint detection.

According to the technical scheme, the incident light conversion structure is arranged above the optical assembly, so that oblique incident light can be converted into vertical incident light to be incident to the optical assembly, light loss caused by oblique light incidence can be reduced, the signal quantity of the optical signal received by the optical sensor can be further improved, the exposure time can be shortened, and the fingerprint identification speed can be improved.

Drawings

Fig. 1 is a schematic plan view of an electronic device to which the present application can be applied.

Fig. 2 is a schematic partial cross-sectional view of the electronic device shown in fig. 1 along a '-a'.

Fig. 3 is a schematic diagram of a fingerprint detection device for fingerprint detection based on oblique light.

Fig. 4 is a schematic diagram of another fingerprint detection device for fingerprint detection based on oblique light.

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

Fig. 6 is a schematic cross-sectional view of an optical fingerprint device according to an embodiment of the present application.

Fig. 7 is a schematic diagram of the principle of operation of a microprism.

Fig. 8 is a schematic diagram of the working principle of a microprism with a reflective coating on the support surface.

Fig. 9 is a perspective view of a microprism array of the microprisms of fig. 6.

Fig. 10 is a schematic structural view of the optical fingerprint device shown in fig. 6 in a plan view.

Fig. 11 is another exemplary cross-sectional view of an optical fingerprint device according to an embodiment of the present application.

Fig. 12 and 13 are top views of the microprism unit of fig. 11.

Fig. 14 is a schematic cross-sectional view of still another example of an optical fingerprint device according to an embodiment of the present application.

Fig. 15 is a schematic structural view of a field of view of an optical fingerprint device of an embodiment of the present application.

Fig. 16 is a schematic cross-sectional view of an example of an optical fingerprint device including an array of microprisms and a light transmissive coating.

Fig. 17 is a schematic diagram of the principle of operation of the structure shown in fig. 16.

Fig. 18 is another exemplary cross-sectional view of an optical fingerprint device including an array of microprisms and a light transmissive coating.

Fig. 19 is a schematic cross-sectional view of another example of an optical fingerprint device including an array of microprisms and a light transmissive coating.

Fig. 20 is a schematic structural diagram of an electronic device according to 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.

As a common application scenario, the fingerprint identification device 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 above terminal device, the fingerprint recognition device may be specifically an optical fingerprint device, which may be disposed in a partial area or an entire area Under the display screen, thereby forming an Under-screen (Under-display) optical fingerprint system.

Fig. 1 and 2 are schematic diagrams of an electronic device to which an embodiment of the present application may be applied, where fig. 1 is a schematic orientation diagram of the electronic device 10, and fig. 2 is a schematic partial cross-sectional structure diagram of the electronic device 10 shown in fig. 1 along a '-a'.

As shown in fig. 1-2, the electronic device 10 comprises a display screen 120 and an optical fingerprint device 130, wherein the optical fingerprint device 130 is disposed in a localized area below the display screen 120, e.g., below a middle area of the display screen. The optical fingerprint device 130 includes an optical fingerprint sensor, where the optical fingerprint sensor includes a sensing array having a plurality of optical sensing units, and an area where the sensing array is located or a sensing area thereof is the fingerprint detection area 103 of the optical fingerprint device 130. As shown in fig. 1, the fingerprint detection area 103 is located in the display area of the display screen 120.

It should be appreciated that the area of the fingerprint detection area 103 may be different from the area of the sensing array of the optical fingerprint device 130, for example, by a light path design such as lens imaging, a reflective folded light path design, or other light converging or reflecting light path design, the area of the fingerprint detection area 103 of the optical fingerprint device 130 may be made larger than the area of the sensing array of the optical fingerprint device 130. In other alternative implementations, the fingerprint detection area 103 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 light path guiding 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 the finger against the fingerprint detection area 103 located on the display screen 120, so as to implement fingerprint input. Since fingerprint detection can be implemented in the screen, the electronic device 10 adopting the above structure does not need to have a special reserved space on the front surface to set fingerprint keys (such as Home keys), so that a comprehensive screen scheme can be adopted, that is, the display area of the display screen 120 can be basically expanded to the front surface of the whole electronic device 10.

As an alternative implementation manner, as shown in fig. 2, the optical fingerprint device 130 includes a light detecting portion 134 and an optical component 132, where the light detecting portion 134 includes the sensing array, and a reading circuit and other auxiliary circuits electrically connected to the sensing array, which may be fabricated on a chip (Die) such as an optical imaging chip or an optical fingerprint sensor through a semiconductor process, and the sensing array specifically includes a Photo detector (Photo detector) array, which includes a plurality of Photo detectors distributed in an array, and the Photo detectors may be used as the optical sensing units as described above; the optical assembly 132 may be disposed over the sensing array of the light detecting portion 134, which may specifically include a Filter layer (Filter) that may be used to Filter out ambient light that penetrates the finger, such as infrared light that interferes with imaging, a light guiding layer or light path guiding structure that is primarily used to guide reflected light reflected from the finger surface to the sensing array for optical detection.

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

The light guiding layer or the light path guiding structure of the optical component 132 may have various implementations, for example, the light guiding layer may be a Collimator (Collimator) layer made of a semiconductor silicon wafer, which has a plurality of collimating units or a micropore array, the collimating units may be small holes, the light vertically incident to the collimating units from the reflected light reflected by the finger may pass through and be received by the optical sensing units below the collimating units, and the light with an excessively large incident angle is attenuated by multiple reflections inside the collimating units, so each optical sensing unit basically only receives the reflected light reflected by the fingerprint lines right above the optical sensing units, and the sensing array may detect the fingerprint image of the finger.

In another embodiment, the light guiding layer or light path guiding structure may also be an optical Lens (Lens) layer having one or more Lens units, such as a Lens group of one or more aspheric lenses, for converging the reflected light reflected from the finger to a sensing array of light detecting portions 134 thereunder, so that the sensing array may image based on the reflected light, thereby obtaining a 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 expand 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 embodiments, the light guiding layer or the light path guiding structure may also specifically employ a Micro-Lens layer having a Micro Lens array formed of a plurality of Micro lenses, which may be formed over the sensing array of the light sensing part 134 by a semiconductor growth process or other processes, and each Micro Lens may correspond to one of sensing units of the sensing array, respectively. And, other optical film layers, such as a dielectric layer or a passivation layer, may be further formed between the microlens layer and the sensing unit, and more particularly, a light blocking 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 cause light corresponding to the sensing unit to be converged into the inside of the micro holes by the microlenses and transmitted to the sensing unit via the micro holes for optical fingerprint imaging.

It should be appreciated that several implementations of the above-described light path guiding structure may be used alone or in combination, e.g. a micro-lens layer may be further provided 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 laminated structure or the optical path thereof may need to be adjusted according to actual needs.

As an alternative embodiment, the display 120 may be a display having a self-luminous display unit, such as an Organic Light-Emitting Diode (OLED) display or a Micro-LED (Micro-LED) display. Taking an OLED display as an example, the optical fingerprint device 130 may use a display unit (i.e., an OLED light source) of the OLED display 120 located in the fingerprint detection area 103 as an excitation light source for optical fingerprint detection. When a finger is pressed against the fingerprint detection area 103, the display 120 emits a light beam to a target finger above the fingerprint detection area 103, and the light beam is reflected on the surface of the finger to form reflected light or scattered inside the finger to form scattered light, and in the related patent application, the reflected light and the scattered light are collectively referred to as reflected light for convenience of description. Since ridges (ribs) of the fingerprint and the ribs (valley) have different light reflection capacities, the reflected light from the ridges of the fingerprint and the emitted light from the ribs of the fingerprint have different light intensities, and the reflected light is received by an induction array in the optical fingerprint device 130 and converted into corresponding electric signals, namely fingerprint detection signals after passing through the optical component; fingerprint image data may be obtained based on the fingerprint detection signal and further fingerprint matching verification may be performed, thereby implementing an optical fingerprint recognition function at the electronic device 10. In other embodiments, the optical fingerprint device 130 may also employ an internal light source or an external light source to provide the optical signal for fingerprint detection.

In other embodiments, the optical fingerprint device 130 may also employ an internal light source or an external light source to provide the optical signal for fingerprint detection. In this case, the optical fingerprint device 130 may be adapted to a non-self-luminous display screen, such as a liquid crystal display screen or other passive light emitting display screen. Taking the application to a liquid crystal display having a backlight module and a liquid crystal panel as an example, in order to support the under-screen 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, the excitation light source may be specifically an infrared light source or a light source of non-visible light with a specific wavelength, which may be disposed under the backlight module of the liquid crystal display or an edge region under a protective cover plate of the terminal device 10, and the optical fingerprint device 130 may be disposed under the edge region of the liquid crystal panel or the protective cover plate and guided through an optical path so that 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 configured to allow fingerprint detection light to pass through the liquid crystal panel and the backlight module and reach the optical fingerprint device 130 by making holes or other optical designs on a film layer such as a diffusion sheet, a brightness enhancing sheet, a reflective sheet, etc. In other alternative implementations, the display 120 may also be a non-self-luminous display, such as a liquid crystal display using a backlight; in this case, the optical detection device 130 cannot use the display unit of the display screen 120 as the excitation light source, so that the excitation light source needs to be integrated inside the optical detection device 130 or provided outside thereof to implement optical fingerprint detection, and when the optical fingerprint device 130 uses an internal light source or an external light source to provide an optical signal for fingerprint detection, the detection principle is consistent with the above description.

It should be appreciated that in particular implementations, the electronic device 10 also includes a transparent protective cover plate that is positioned over the display screen 120 and covers the front of the electronic device 10. Because, in the embodiment of the present application, the so-called finger pressing 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 embodiments, the optical fingerprint device 130 may include only one optical fingerprint sensor, where the area of the fingerprint detection area 103 of the optical fingerprint device 130 is small and the position is fixed, so that the user needs to press the finger to a specific position of the fingerprint detection area 103 when inputting the fingerprint, otherwise, the optical fingerprint device 130 may not be able to acquire the fingerprint image, which may cause poor user experience. In other alternative embodiments, the optical fingerprint device 130 may specifically include a plurality of optical fingerprint sensors; the plurality of optical fingerprint sensors may be disposed in a side-by-side manner in a middle area of the display screen 120, and sensing areas of the plurality of optical fingerprint sensors together form the fingerprint detection area 103 of the optical fingerprint device 130. That is, the fingerprint detection area 103 of the optical fingerprint device 130 may include a plurality of sub-areas, each corresponding to a sensing area of one of the optical fingerprint sensors, so that the fingerprint acquisition area 103 of the optical fingerprint device 130 may be extended to a main area of the middle portion of the display screen, that is, to a finger usual press area, thereby implementing a blind press type fingerprint input operation. Alternatively, when the number of optical fingerprint sensors is sufficient, the fingerprint detection area 130 may also be extended to half or even the whole display area, thereby achieving half-screen or full-screen fingerprint detection.

Optionally, in some embodiments of the present application, the optical fingerprint device 130 may further include a circuit board for transmitting signals (e.g., the fingerprint detection signals), for example, the circuit board may be a flexible circuit board (Flexible Printed Circuit, FPC). The optical fingerprint sensor may be connected to an FPC and electrically interconnected and signal-transmitting with other peripheral circuits or other elements in the electronic device through the FPC. For example, the optical fingerprint sensor may receive a control signal of a processing unit of the electronic device through the FPC, and may also output a fingerprint detection signal (e.g., a fingerprint image) to the processing unit or the control unit of the electronic device through the FPC.

In the following embodiments, the same reference numerals are used for the same structures in the structures shown in the different embodiments, and detailed description of the same structures is omitted for brevity.

It should be understood that the heights or thicknesses of the various structural components in the embodiments of the present application shown below, as well as the overall thickness of the optical fingerprint device, are merely illustrative and should not be construed as limiting the present application in any way.

In some embodiments, in order to improve the flexibility of fingerprint identification, a scheme of fingerprint detection based on oblique light is proposed, and fig. 3 and fig. 4 respectively show schematic block diagrams of a fingerprint detection device for fingerprint detection based on oblique light.

As shown in fig. 3, the fingerprint detection device 20 may include a micro lens 21, a micro aperture 22 disposed on a back focal plane 211 of the micro lens 21, an optical sensing unit 23 disposed below the micro aperture 22, and a filter 25 disposed above the micro lens 21.

When the incident angle isAfter the finger reflected light 24 of (a) enters the fingerprint detection device 20, the finger reflected light passes through the optical filter 25, the optical filter 25 has higher transmittance to light in a visible light wave band and lower transmittance to infrared light, and can be used for preventing light signals in an infrared wave band in sunlight from penetrating through the finger to collect fingerprint imagesInterference. The reflected light 24 then passes through the microlens 21 and is converged to a point F on the back focal plane 211 of the microlens ₁ . Wherein F is ₁ From the back focus F of the microlens 21 ₀ Distance F of (2) ₀ F ₁ Can be approximated as:

where r is the radius of curvature of the microlens 21 and n is the refractive index of the microlens 21. The aperture of the aperture diaphragm 22 is arranged at F1, the area outside the aperture diaphragm 22 is provided with a non-light-transmitting layer 220, and the size of the aperture diaphragm determines the angle range of the incident light passing through Only the incident angle is +.>To-> The light 24 reflected by the finger in the range reaches the optical sensing unit 23. The combination of the micro lens 21 and the micro aperture 22 can realize the angle screening of the incident light, and the incident light with a non-target angle is blocked by the non-light-transmitting layer 220.

However, when it comes to receiving high angle optical signals (e.g., angle of incidenceGreater than 30 degrees), the scheme shown in fig. 3 faces two problems: firstly, the transmittance of the optical filter 25 for large-angle incident light is lower than that for normal incident light; secondly, a partial region (e.g., region 241 in fig. 3) of the microlens 21 cannot play a role in convergence due to a shadow effect (lens shading effect). Therefore, the fingerprint detection device 20 is caused to have a large light loss when receiving incident light of a large angleIt is therefore necessary to rely on extending the exposure time of the fingerprint detection device 20 to obtain a sufficient amount of signal, which can result in a long fingerprint recognition time, which can affect the user experience.

As shown in fig. 4, the fingerprint detection device 30 may include a filter 35, a tilted-hole collimator 36 (provided with a plurality of tilted holes 361) disposed below the filter 35, and an optical sensing unit 33 below the tilted-hole collimator 36. Because the inclined hole 361 is arranged in the direction with the angle with the normal line 310 Therefore, the optical sensing unit 33 can only receive the reflected light 34 of the finger with an incident angle +.>Or approach->Is provided.

The solution shown in fig. 4 still has the problem that the optical filter 35 has a low transmittance for the oblique incident light of a large angle. In addition, the process of manufacturing the inclined hole collimator 36 is relatively complex, and the manufacturing difficulty is high, so that the method is not suitable for mass production.

Further, in order to solve the above-mentioned problems, an embodiment of the present application proposes an optical fingerprint device, as shown in fig. 5, the optical fingerprint device 70 may include an incident light conversion structure 71, an optical component 72 and an optical sensor 73, wherein:

the incident light conversion structure 71 is disposed above the optical assembly 72, and is configured to convert a first optical signal returned from a finger into a second optical signal, where the first optical signal is an optical signal inclined with respect to a plane of an optical sensor, and the second optical signal is an optical signal perpendicular to the plane of the optical sensor;

the optical component 72 is disposed above the optical sensor 73, and is configured to receive the second optical signal and transmit the second optical signal to the optical sensor 73;

the optical sensor 73 may include a plurality of optical sensing units for receiving the second optical signal transmitted through the optical assembly 72 and acquiring fingerprint information of the finger according to the second optical signal.

Therefore, in the embodiment of the application, the incident light conversion structure is arranged above the optical assembly, so that oblique incident light can be converted into vertical incident light to be incident to the optical assembly, the optical loss caused by oblique light incidence can be reduced, the signal quantity of the optical signal received by the optical sensor can be further improved, and compared with the scheme of the inclined hole collimator, the technical scheme is simple in process and easy to realize.

Alternatively, in some embodiments, the incident light conversion structure 71 may be a structure composed of a micro prism, and the micro prism may have an inclined incident surface, and may be used to convert the incident light incident on the inclined incident surface into an optical signal perpendicular to the display screen, or in other embodiments, the incident light conversion structure may be a structure made of other materials having a high refractive index, so long as the above-mentioned function can be achieved, which is not limited by the embodiments of the present application. Hereinafter, the incident light conversion structure will be described as an example of a microprism structure, but embodiments of the present application are not limited thereto.

As an example, the optical fingerprint device 70 may be the optical fingerprint device 40 shown in fig. 6. As shown in fig. 6, the optical fingerprint device 40 may include a light guiding part 41 and a light detecting part 42. Wherein the light guiding portion 41 may be used to guide the light signal reflected or scattered via the finger to the light detecting portion 42. The light guiding portion 41 may comprise an incident light converting structure and an optical component (e.g. optical component 132 in fig. 2), corresponding to the incident light converting structure 71 and optical component 72 in fig. 5, respectively, and in a further embodiment the light guiding portion 41 may further comprise a light transmissive coating, as described in detail below.

The light detecting part 42, which corresponds to the optical sensor 73 of fig. 5, may include an optical sensing array 424, which may include a plurality of optical sensing units. For example, the optical sensing array 424 may include a first optical sensing unit 424a, a second optical sensing unit 424b, and a third optical sensing unit 424c. The optical signal received by the optical sensing array 424 is used to detect fingerprint information of the finger.

The incident light conversion structure may be, for example, a micro prism array 410 shown in fig. 6, which may include a plurality of micro prisms (micro-prisms), for example, a first micro prism 410a, a second micro prism 410b, a third micro prism 410c, and the like. The microprism array 410 may be used to convert a first optical signal reflected via a finger into a second optical signal. The first optical signal may be an optical signal inclined relative to the display screen, and the second optical signal may be an optical signal perpendicular relative to the display screen. Alternatively, the first optical signal may be an optical signal inclined with respect to the plane of the light detecting portion 42, and the second optical signal may be an optical signal perpendicular with respect to the plane of the light detecting portion 42.

In some embodiments, at least one optical sensing unit is disposed under each micro prism in the micro prism array 410, for example, at least a first optical sensing unit 424a is disposed under the first micro prism 410a, at least a second optical sensing unit 424b is disposed under the second micro prism 410b, and at least a third optical sensing unit 424c is disposed under the third micro prism 410 c.

Further, the light detecting section 42 may further include at least one metal layer 421 and a dielectric layer 423. The metal layer 421 may be a metal wiring layer of the optical sensing array 424, and is used for electrically interconnecting optical sensing units in the optical sensing array 424 and electrically connecting the optical sensing array 424 to external devices to enable communication with other devices in the electronic device. The dielectric layer may be disposed between the metal layers 421 and the optical sensing array 424, and the material of the dielectric layer 423 may be a transparent material.

In some embodiments of the present application, the optical component may be disposed between the micro prism array 410 and the optical sensing array 424, and the optical component may be used to screen or separate the second optical signal converted by the micro prism array 410. That is, the optical component may be used to screen out a portion of the second optical signal converted by the micro prism array 410 and guide the portion of the second optical signal to a specific optical sensing unit in the optical sensing array 424. In this embodiment, the optical assembly is configured to direct the second optical signal converted by the corresponding microprism to the optical sensing unit below the microprism. For example, after the first optical signal returned from the finger above the display screen is converted into the second optical signal through the micro prism 410a, the second optical signal is transmitted to the optical sensing unit 424a disposed below the micro prism 410a through the corresponding optical component (e.g., the micro lens 412 a).

In practical products, since the thickness of the micro prism array 410 is generally thin, the thickness of the optical fingerprint device 40 can be ensured to be small.

It should be understood that fig. 6 only shows a scenario in which one micro-prism corresponds to one optical sensing unit, in other embodiments, one micro-prism may also correspond to a plurality of optical sensing units, i.e. a plurality of optical sensing units may be disposed under the micro-prism, i.e. after the first optical signal returned from the finger above the display screen is converted into the second optical signal by the one micro-prism, the second optical signal may be further transmitted to the plurality of optical sensing units through the corresponding optical component, for example, if the micro-prism 410a corresponds to the optical sensing units 424a and 424b, the first optical signal returned from the finger above the display screen is converted into the second optical signal by the micro-prism 410a, and then the second optical signal converted by the micro-prism 410a is further transmitted to the optical sensing units 424a and 424b disposed under the micro-prism 410a through the corresponding optical component (for example, the micro-lens 412 a).

Optionally, in some embodiments, when one micro prism corresponds to a plurality of optical sensing units, a projection of the micro prism on a plane where the optical sensing array is located covers the corresponding plurality of optical sensing units, so as to ensure that the optical signal converted by the micro prism can reach the plurality of optical sensing units maximally.

Alternatively, in some embodiments, the optical assembly may include a microlens array and at least one light blocking layer, as shown in fig. 6, the microlens array 412 includes a plurality of microlenses, for example, a first microlens 412a, a second microlens 412b, a third microlens 412c, and the like, disposed under the microlens array 410; the at least one light blocking layer may be disposed between the microlens array 412 and the optical sensing array 424, and each of the at least one light blocking layer is provided with an opening therein corresponding to the microlens array or the optical sensing unit. Wherein the optical sensing array 424 is configured to receive optical signals converged by the microlens array 412 and transmitted through the aperture of the at least one light blocking layer. Alternatively, the microlens array 412 is configured to receive the second optical signal converted by the micro-prism array and transmit the second optical signal to the optical sensing array 424 through the opening in the at least one light blocking layer.

Alternatively, as an example, as shown in fig. 6, the at least one light blocking layer includes a first light blocking layer and a second light blocking layer 414, wherein openings corresponding to each microlens in the microlens array 412 are respectively provided in the first light blocking layer and the second light blocking layer 414. For example, the metal layer 421 in the light detecting portion 42 may be multiplexed as the first light blocking layer to simplify the structure of the optical fingerprint device, such that the first light blocking layer 421 is provided therein with the first aperture 422a corresponding to the first microlens 412a, the second aperture 422b corresponding to the second microlens 412b, and the third aperture 422c corresponding to the third microlens 412 c. Similarly, fourth openings 415a corresponding to the first microlenses 412a, fifth openings 415b corresponding to the second microlenses 412b, and sixth openings 415c corresponding to the third microlenses 412c are provided in the second light blocking layer 414.

The first optical sensing unit 424a is configured to receive an optical signal converged by the first microlens 412a and transmitted through the fourth aperture 415a and the first aperture 422 a. The second optical sensing unit 424b is configured to receive the optical signal converged by the second microlens 412b and transmitted through the fifth aperture 415b and the second aperture 422 b. The third optical sensing unit 424c is configured to receive the optical signal converged by the third microlens 412c and transmitted through the sixth aperture 415c and the third aperture 422 c.

It should be understood that in the scheme shown in fig. 6, one microlens may correspond to one optical sensing unit, i.e., the microlens may guide the second optical signal transmitted through the microprism to one optical sensing unit, or one microlens may correspond to a plurality of optical sensing units, i.e., the microlens may guide the second optical signal transmitted through the microprism to a plurality of optical sensing units, in which case one opening in the at least one light blocking layer may correspond to a plurality of optical sensing units through which the optical signals transmitted to the plurality of optical sensing units may all be transmitted.

Therefore, compared with the solution shown in fig. 4, the solution shown in fig. 6 converts the optical signal reflected by the finger and inclined with respect to the display screen into the signal perpendicular to the display screen through the micro-prism array 410, and then converges the perpendicular optical signal through the micro-lens and the light blocking layer, so as to reduce the shadow effect of the edge area of the micro-lens, and further improve the signal quantity received by the optical sensing array 424, thereby shortening the exposure time and the fingerprint recognition time.

Alternatively, in some embodiments, the first light blocking layer is disposed at a back focal plane position of a microlens in the microlens array, wherein the back focal plane of the microlens array may be a plane formed by a back focal point of each microlens in the microlens array. The focusing point of the micro lens is in the opening in the first light blocking layer, so that the second optical signal obtained through conversion of the micro prism enters the micro lens corresponding to the micro prism, is converged by the micro lens and is transmitted to the opening in the first light blocking layer, and is further transmitted to the corresponding optical sensing unit through the opening.

As described above, the metal layer 421 in the light detecting portion 42 may be multiplexed as the first light blocking layer, that is, the first light blocking layer may be disposed inside the light detecting portion 42, for example, the first light blocking layer 421 may be formed using a metal layer in a back-end-of-line (BEOL) process, which may be the metal layer 421 at any position in the light detecting portion 42, for example, a metal layer at a bottom position, an intermediate position, or a top position. By multiplexing the metal wiring layer of the optical sensing array 424 as a light blocking layer, the thickness of the optical fingerprint device 40 can be advantageously reduced.

It should be noted that, in the embodiment of the present application, an optical sensing unit, and an optical component (for example, the optical filter, the microlens, and the light blocking layer in fig. 6, or the optical filter and the one or more collimation holes in fig. 14) disposed thereon, and the microprism may form an optical image capturing unit, and the optical image capturing unit may be used to form one pixel of a captured image, and an array of a plurality of optical image capturing units may form the optical fingerprint device.

It should be understood that in embodiments of the present application, the at least one light blocking layer may include only the first light blocking layer, and in other embodiments, the at least one light blocking layer may include the first light blocking layer and the second light blocking layer 414, the second light blocking layer 414 being for avoiding interference between adjacent optical image capturing units. In some embodiments, the second light blocking layer 414 may be disposed between the microlens array and the first light blocking layer; in other embodiments, the second light blocking layer may be disposed between adjacent microlenses or on the upper or lower surface of the filter. Alternatively, in some embodiments, the openings in the first light blocking layer corresponding to the same microlens are smaller than the openings in the second light blocking layer 414, for example, the openings 415a in the first light blocking layer corresponding to the microlens 412a are larger than the openings 422a in the second light blocking layer 421 corresponding to the microlens 412 a.

Further, in some embodiments, the optical fingerprint device 40 may further include a planar layer (planarization layer) 411 over the microlens array 412, and an optical path layer 413 under the microlens array 412. The flat layer 411 and the light path layer 413 may be formed of a light-transmitting material, and a second light blocking layer 414 formed of a light-impermeable material may be disposed within the light path layer 413.

Optionally, in some embodiments, the optical component may further include a filter 416, which may be fabricated at any position along the optical path to the optical sensor array 424 via the reflected light formed by the finger reflection, which is not particularly limited in this embodiment of the present application. For example, the optical filter 416 may be disposed above the microlens array 412, or may be disposed below the microlens array 412, or may be disposed above the optical sensing unit, or the like. Alternatively, the filter 416 may be an infrared cut filter (IR cut filter).

The entry of the vertical optical signal into the filter reduces the loss of optical signals as compared to the direct passage of the oblique optical signal through the filter 416, and eliminates the need to customize the filter 416, thereby reducing its manufacturing complexity.

In an embodiment of the present application, the optical filter 416 is used to reduce unwanted ambient light in fingerprint sensing to enhance optical sensing of the received light by the optical sensing array 424. The filter 416 may be specifically used to filter out light of a particular wavelength, such as near infrared light and a portion of red light, etc. For example, if a human finger absorbs a large portion of the energy of light having a wavelength below 580nm, if one or more optical filters or optical filter layers are designed to filter light having wavelengths from 580nm to infrared, the impact of ambient light on optical detection in fingerprint sensing may be greatly reduced.

For example, the filter 416 may include one or more optical filters, which may be configured, for example, as bandpass filters, to allow transmission of light emitted by the OLED screen while blocking other light components, such as infrared light, in sunlight. Such optical filtering may be effective in reducing the background light caused by sunlight when the optical fingerprint device 40 is used outdoors. The one or more optical filters may be implemented, for example, as an optical filter coating formed on one or more continuous interfaces, or may be implemented as one or more discrete interfaces. In addition, the light incident surface of the optical filter 416 may be provided with an optical coating, so that the reflectivity of the light incident surface of the optical filter is lower than a first threshold, for example, 1%, so that the optical sensing array 424 can be ensured to receive enough optical signals, and further fingerprint recognition effect is improved.

In the example shown in fig. 6, the microprism array 410 may only receive a return from a finger at a particular angleAn incident optical signal (e.g., optical signal 43 shown in fig. 6). Taking the second microprism 410b as an example, by angle +.>The incident optical signal 43 is converted into a vertical optical signal after passing through the second microprism 410 b. The vertical optical signal first passes through the optical filter 416 to filter out the light of the non-target wavelength band, and then passes through the second micro lens 412b to be converged at the back focus of the micro lens 412b under the action of the micro lens, that is, to be converged in the fifth opening 422b corresponding to the second micro lens 412b, and the optical signal passing through the fifth opening 422b is received by the corresponding optical sensing unit 424 b. Because the light intensity of the light from the fingerprint valley is larger than that from the fingerprint ridge, the electric signal output by the optical sensing unit corresponding to the fingerprint valley is stronger and the image is brighter; the optical sensing units corresponding to the fingerprint ridges output weaker electric signals and darker images, and finally clear fingerprint images with certain contrast are output.

Optionally, in some embodiments, the microprism may include at least one first entrance face, at least one first support face and at least one first exit face, provided that the at least one first exit face is parallel to the display screen and the at least one first entrance face forms a second angle with the at least one first exit face to enable the microprism to convert the first optical signal into the second optical signal. Next, the operation principle of the microprisms will be described with reference to fig. 7 by taking the second microprisms 410b in the microprism array 410 shown in fig. 6 as an example.

Specifically, the second microprism 410b includes a first incident surface 501, a first exit surface 502, and a first support surface 500. When the incident light 51 reaches the first incident surface 501, a part of the light is reflected to form reflected light 53, and the remaining part is refracted to form refracted light 52, which is emitted from the first emission surface 502.

Assuming that the first optical signal forms a first included angle with a direction perpendicular to the display screen, the first included angle and a second included angle between the first incident surface and the second exit surface may satisfy the following formula (1):

wherein θ represents the second included angle,represents the first included angle, n ₁ Indicating the refractive index of the propagation medium of the incident light 51, n ₂ Representing the refractive index of the microprisms.

Assume thatThe refractive index of the second microprism 410b is 1.56, and the incident light 51 is incident from air, i.e., n ₁ =1. The second included angle was found to be 35.8 degrees by the above formula. That is, in case that the refractive index of the micro-prism is 1.56, the second micro-prism 410b having the second angle of 35.8 degrees may convert the first optical signal having the first angle of 30 ° into the second optical signal vertically outgoing.

As can be seen from the above formula (1), at a first angle By controlling the refractive index n of the second microprisms in a fixed condition ₂ The second included angle θ of the second microprisms may be controlled, for example, by setting the refractive index n of the microprisms ₂ The second included angle θ of the microprisms is smaller, that is, the microprisms made of high refractive index materials are adopted, so that the thickness of the microprisms is reduced, and the overall thickness of the optical fingerprint device can be reduced.

It should be noted that, since the optical signals reflected by the finger include optical signals in all directions, the specific value of the first included angle is not limited in the embodiment of the present application. The person skilled in the art can determine the angle of the second included angle formed by the entrance face and the exit face of the microprisms in the microprism array 410 according to the angle of the oblique light signal reflected by the finger to be actually collected. Preferably, the first included angle is greater than or equal to 20 degrees. That is, the optical fingerprint device 40 can detect fingerprint information of a finger based on a large-angle oblique light signal, thereby improving fingerprint recognition effect.

Optionally, in the embodiment of the present application, the micro prism having the second included angle may be manufactured by a process such as nanoimprint or gray scale lithography, and the process is mature, which is not described herein.

In the above example, the first supporting surface may be light-transmitting or may be light-impermeable, which is not limited by the embodiment of the present application.

In other embodiments, the microprism may include at least one first incident surface, at least one first supporting surface and at least one first emergent surface, where the at least one supporting surface is provided with a reflective layer, where a first optical signal returned from a finger is incident on the first incident surface and enters the microprism to form a third optical signal, where the third optical signal is incident on the first incident surface again after being reflected by the first supporting surface, and the second optical signal that is perpendicularly emergent after being reflected again from the first incident surface, i.e., the reflective layer is used to make the optical signal incident on the first supporting surface undergo specular reflection on the first supporting surface to form a perpendicularly emergent optical signal, and the reflective layer may be a metal coating, for example, a silver coating, an aluminum coating, or the like, and the microprism may be a litterlol prism.

The at least one first exit surface is assumed to be parallel to the display screen and the at least one first entrance surface forms a second angle with the at least one first exit surface such that the microprisms are capable of converting the first light signal into the second light signal. Next, the operation principle of the microprisms will be described with reference to fig. 8 by taking the second microprisms 410b in the microprism array 410 shown in fig. 6 as an example.

Specifically, the second microprism 410b includes a first incident surface 501, a first exit surface 502, and a first supporting surface 505, where the first supporting surface 505 is provided with a reflective layer. When the incident light 51 reaches the first incident surface 501, a part of the light is reflected to form reflected light 53, the rest of the light is refracted to form refracted light 54 (i.e., third light signal), the refracted light 54 is specularly reflected on the first supporting surface 505, and the reflected light 56 reaches the first incident surface 501 again, and at this time, the angle between the reflected light 56 and the normal line 503 of the first incident surface 501 is greater than the critical angle, so that total reflection occurs to form reflected light 52, and the reflected light is emitted perpendicularly to the first emitting surface 502.

In this embodiment, the incident light 51 forms a first angle with the direction perpendicular to the optical sensorThe first incident surface and the first exit surface form a second included angle θ, the refracted light 54 forms a third included angle α with a direction perpendicular to the first incident surface 501, and the refracted light 54 forms a fourth included angle β with a direction parallel to the first exit surface 502, wherein the first included angle->The second included angle theta, the third included angle alpha, the fourth included angle beta, the refractive index n of the propagation medium of the first optical signal ₁ Refractive index n of the microprism ₂ The following formula (2) is satisfied:

beta= (90 ° - θ) +alpha formula (2).

θ＝(90°-θ)+β

Hereinafter, a specific arrangement of the micro prism array 410 according to an embodiment of the present application will be described with reference to fig. 9 to 13.

Alternatively, as an embodiment, denoted as mode 1, the micro-prism array 410 may include a plurality of micro-prism units distributed in an array, and each micro-prism unit may include one micro-prism, and the one micro-prism may correspond to one optical sensing unit, for example, the optical sensing unit may be disposed below an incident surface of the micro-prism, so that the micro-prism and an optical assembly and the optical sensing unit disposed below the micro-prism may form one optical image capturing unit.

Alternatively, as another embodiment, denoted as mode 2, the micro-prism array 410 may include a plurality of micro-prism units distributed in an array, and each micro-prism unit may include one micro-prism, and the one micro-prism may correspond to a plurality of optical sensing units, for example, each micro-prism may correspond to a row of optical sensing units or a column of optical sensing units in the optical sensing array, for example, the row or column of optical sensing units may be disposed below an incident surface of the micro-prism. That is, the plurality of microprism units may include a column or a row of microprisms distributed in an array, each microprism being in a long stripe shape.

Fig. 9 may be a schematic perspective view of the micro prism array 410 shown in fig. 6 implemented in manner 2. As shown in fig. 9, the micro prism array 410 may include a row of micro prisms, and a column of optical sensing units may be disposed under each micro prism. That is, in fig. 6, the first, second and third micro prisms 410a, 410b and 410c may be bar-shaped structures.

It should be understood that, in the embodiment of the present application, the number of the microlenses disposed between the microprisms and the optical sensing units is not limited, when one microprism may correspond to one row of optical sensing units, one microlens may be disposed under the one microprism, and the microlens may also have a strip structure, corresponding to the one row of optical sensing units, in this case, the second optical signal converted by the microprism reaches the one row of optical sensing units after being transmitted through the one microlens; alternatively, a row of microlenses may be disposed below the microprisms, where each microlens corresponds to one optical sensing unit, and in this case, the second optical signal converted by the microprism reaches the optical sensing unit corresponding to each microlens after being transmitted through the row of microlenses.

Fig. 10 is a top view of an optical fingerprint device 40 according to an embodiment of the present application. It should be understood that the number of microprisms and microlenses shown in the drawings is merely an example, and the present application is not limited thereto.

Alternatively, as yet another embodiment, denoted as mode 3, as shown in fig. 11, the micro-prism array 410 may include a plurality of micro-prism units 810 distributed in an array, and each micro-prism unit 810 may include a plurality of micro-prisms having a plurality of incident planes in different directions and may be used to receive optical signals returned from different directions via a finger. Optionally, the projection of the plurality of microprisms on the plane where the optical sensing unit is located may be a quadrangle, a pentagon or other shapes, which is not limited in the embodiment of the present application. The projected area of each micro prism of the micro prism unit 810 on the plane of the optical sensing unit array 424 may be equal to or approximately equal to the projected area of each micro lens of the micro lens array on the plane of the optical sensing unit 424, so as to improve the utilization rate of the micro prism unit 810 and reduce the volume of the optical fingerprint device 40.

Fig. 12 to 13 are schematic plan views illustrating an example in which a micro prism unit includes four micro prisms, and fig. 12 is a cross-sectional view of an optical fingerprint device along the E-E' direction, and it should be understood that one micro prism unit is illustrated in the drawings, but the present application is not limited thereto.

Referring to fig. 12, the micro prism unit 810 may include 4 micro prisms, for example, the 4 micro prisms are distributed in a central symmetry. Further, one microlens may be disposed under each of the microprisms in each of the microprism units 810. At least one light blocking layer is arranged below each microlens, an opening is arranged in the light blocking layer, and an optical sensing unit is arranged below the opening.

It should be appreciated that in this embodiment, a micro prism unit 810 and the optical components contained thereunder and the light detecting section 42 may be used to constitute a parent unit of the fingerprint detection device 40. That is, each mother unit is composed of four sub units (sub unit a, sub unit b, sub unit c, and sub unit d) including a first micro prism 810a, a second micro prism 810b, a third micro prism 810c, a fourth micro prism 810d, and optical components and light detection parts corresponding therebelow, respectively, each sub unit may form one optical image capturing unit for forming one pixel of a captured image, and one mother unit may be used for forming four pixels of the captured image, i.e., 2 rows by 2 columns of pixels.

As an example, the micro prism unit 810 composed of the first micro prism 810a, the second micro prism 810b, the third micro prism 810c, and the fourth micro prism 810d may be constructed as one flat-head pyramid. I.e., a pyramid from which the tips are cut, e.g., a micro-prism unit 810 composed of a first micro-prism 810a, a second micro-prism 810b, a third micro-prism 810c, and a fourth micro-prism 810d may be inscribed in a regular quadrangle to form the flat-headed pyramid, i.e., a top view of the micro-prism unit 810 may be an area surrounded by ABCD as shown in fig. 12. Alternatively, fig. 12 may be a top view of fig. 11 in the OA direction.

If a coordinate system is established with the transverse direction as the X-axis and the longitudinal direction as the Y-axis, the directions of the first microprism 810a, the second microprism 810b, the third microprism 810c and the fourth microprism 810d relative to the origin O are different, for example, angle aox=135°, angle box=45°, angle cox= -45 °, and angle dox= -135 °.

That is, the adjacent two microprisms in the microprism unit 810 are 90 degrees different in angle from the origin O. Thus, the microprism unit 810 may be configured to receive light from four different directions at an angle of incidenceThe light 831 and 832 of fig. 11 show two directions therein) can effectively reduce the dependence on the finger placement angle at the time of fingerprint authentication.

For example, the micro prisms in the micro prism unit array may be divided into a plurality of groups, each group of micro prisms is used for receiving an optical signal in one direction, the optical sensing units in the optical sensing array are divided into a plurality of groups, each group of optical sensing units may be used for receiving an optical signal in one direction, each micro prism in each group of micro prisms may be used for converting the optical signal in one direction into a vertical optical signal and transmitting the vertical optical signal to a corresponding micro lens, and further transmitting the vertical optical signal to a corresponding group of optical sensing units through the micro lens, the optical signals received by the group of optical sensing units may be used for generating one fingerprint image, so that the optical signals received by the plurality of groups of optical sensing units may be used for generating a plurality of fingerprint images, and further processing the plurality of fingerprint images may obtain one complete fingerprint image.

Therefore, in the embodiment of the application, the exposure time of the optical sensing array can be reduced by arranging the microprism unit to receive the optical signals at a plurality of angles, so that the fingerprint identification time can be shortened, and the dependence of fingerprint acquisition on the angle of incident light can be reduced.

Further, by each micro prism unit 810 receiving light signals of a plurality of angles, the field of view of the fingerprint detection device 40 may be increased.

Fig. 14 is a side cross-sectional view of the electronic device with the display screen along the direction E-E' shown in fig. 13.

Referring to fig. 14, the electronic device 60 may include a display screen 61 and a fingerprint detection device 40 located below the display screen, wherein a micro prism unit in the fingerprint detection device 40 may be used to receive light signals in 4 directions. For example, a third microprism 810c may be used to receive the light signal in a second direction, i.e., the second field of view shown in the figure may be the field of view of the third microprism 810c, and similarly the first field of view shown in the figure may be the field of view of the first microprism 810 a. That is, the fingerprint detection device 40 has a third field of view in the direction E-E' that is larger than the first field of view and larger than the second field of view, effectively increasing the field of view of the fingerprint detection device 40.

It should be understood that embodiments of the present application do not limit the number of entrance facets of the microprisms in the microprism array 410. For example, each of the plurality of microprisms includes at least one entrance face, and at least one optical sensing unit is disposed under each entrance face of each of the plurality of microprisms; for another example, each of the plurality of microprisms includes a plurality of entrance facets that are axisymmetric or centrosymmetric.

It should also be appreciated that embodiments of the present application are not limited to the particular shape in the microprism array 410. For example, each of the plurality of microprisms is a triangular prism or a trapezoidal prism; for another example, each of the plurality of microprisms is a right angle prism, and an incident surface of each of the plurality of microprisms is a bevel of the right angle prism; as another example, each micro prism in the array of micro prisms 410 includes, but is not limited to, any one of the following: right angle triangular prism, isosceles triangular prism, right angle trapezoidal prism and isosceles trapezoidal prism.

Optionally, the embodiment of the present application does not limit the specific structure of the optical component. For example, it may be the optical assembly 132 shown in fig. 2. For example, the optical component may include a microlens array and a light blocking layer, or may be a straight-hole collimator. For example, the straight hole collimator comprises a plurality of straight holes, wherein each optical sensing unit is for receiving an optical signal transmitted via one or more of the straight holes. Further, the optical assembly may further include a filter.

Fig. 15 is a schematic cross-sectional view of an optical fingerprint device in which the optical assembly is implemented using a straight-hole collimator. As shown in fig. 15, the optical component is a straight hole collimator 911, and the straight hole collimator 911 may be disposed between the micro prism array 410 and the light detecting portion 42, and the straight hole collimator 911 may include a plurality of straight holes 912 arranged in a certain manner, and each optical sensing unit may correspond to one or more of the straight holes 912. For example, each optical sensing unit may correspond to 3 collimating apertures 912. Incident angle isIs converted to a vertical light signal by the micro prism array 410, and is further transmitted to the optical sensing array 424 by the straight collimator 911. The incident angle is not +.>Is blocked by the straight collimator 911 and thus does not reach the optical sensing array 424.

Compared with the inclined hole collimator scheme shown in fig. 4, the micro prism array 410 converts the optical signals returned by the finger and inclined relative to the display screen into signals vertical to the display screen, and then the straight hole collimator 911 transmits the optical signals to the photoelectric sensing array, so that the manufacturing difficulty and cost of the collimator are effectively reduced.

In addition, since the angular screening capability of the straight-hole collimator 911 is mainly dependent on the aspect ratio (ratio of depth to aperture) of the collimating holes 912, the straight holes with small apertures are advantageous for improving the resolution of the image, but reduce the light incoming amount, and thus the exposure time of the optical sensor array 424 needs to be prolonged. In the embodiment of the present application, a plurality of straight holes are disposed above each optical sensing unit, so that the exposure time of the optical sensing array 424 can be effectively reduced, and further the user experience can be improved.

It should be understood that fig. 15 is only one exemplary structure of the present application, and should not be construed as limiting the present application in any way.

For example, the optical sensing array 424 and the straight collimator 911 may also be integrally provided. For example, the straight hole collimator 911 may be integrated within the light detecting portion 92, for example, a metal layer and a metal via layer in a subsequent process may be used to form the straight hole in the straight hole collimator 911.

The principle of angular conversion of a microprism is described above in connection with fig. 6 to 15, and in some cases, if the angle of incidence of the optical signal returned from the finger is too large, for example, in the example shown in fig. 7,when the refractive index of the microprism is 1.5, the angle θ between the incident surface and the exit surface of the microprism is 41.2 degrees, and the angle of the incident light with respect to the normal line of the incident surface of the microprism is +. > I.e., 81.2 degrees, at this time, about 43% of the incident light is reflected at the air/microprism interface, so it is still necessary to extend the exposure time to make up for the shortage of the light input, increasing the fingerprint recognition time, and affecting the user experience.

Based on the problem, in the embodiment of the application, a light-transmitting coating layer can be arranged on the incident surface of the incident light angle conversion structure, wherein the refractive index of the light-transmitting coating layer is larger than that of the incident light angle conversion structure, so that the incident light is opposite to the first incident surface of the incident light angle conversion structure, the light entering quantity of the incident light to the optical sensing array can be increased, and the exposure time and the fingerprint identification time are shortened.

In the following, referring to fig. 16 to 19, an incident light angle conversion structure is taken as an example of a micro prism array, and when the incident light angle conversion structure is other structures, implementation manners are similar, and will not be repeated here.

Fig. 17 to 19 are schematic cross-sectional views of an optical fingerprint device having a light-transmitting coating disposed on an incident light conversion structure, and as shown in fig. 17 to 19, the light guiding portion 41 may further include, in addition to the structure described in the foregoing embodiment: a light-transmitting coating 417 disposed on an incident surface of the incident light conversion structure, for example, if the incident light conversion structure is a micro prism array, the light-transmitting coating 417 is disposed on an incident surface of a micro prism in the micro prism array 410, the light-transmitting coating 417 is configured to convert a first light signal returned from a finger into a fourth light signal, and further the fourth light signal is incident on an incident surface of a micro prism in the micro prism array 410 and converted into a second light signal that is emitted vertically through the micro prism array 410, wherein a refractive index of the light-transmitting coating 417 is greater than a refractive index of a material of the micro prism. The following describes the specific implementation of the light-transmitting coating layer by taking the incident light conversion structure as a microprism array as an example, but the present application is not limited thereto. It should be understood that the specific description of each structural component in the optical fingerprint device shown in fig. 17 to 19 refers to the related description of the foregoing embodiment, and will not be repeated here.

Therefore, in the embodiment of the application, by arranging the light-transmitting coating with high refractive index on the incident surface of the micro-prism array, the first light signal returned from the finger can be converted into the light signal which is emitted vertically after being refracted twice, on one hand, the direction of the incident light can be converted, so that the light signal which is opposite to the first incident surface of the micro-prism array is refracted at the air/light-transmitting coating interface and is converted into the vertical light signal, and finally reaches the optical sensing array, on the other hand, the light-transmitting coating with high refractive index is adopted, and the included angle between the incident surface and the emitting surface of the micro-prism is smaller under the condition of the same incident angle, thereby being beneficial to reducing the thickness of the micro-prism and further reducing the integral thickness of the optical fingerprint device.

It should be understood that the thickness, shape, etc. of the light-transmitting coating are not limited in this embodiment of the present application, as long as it can cooperate with the micro-prism array to convert the first optical signal into the second optical signal that is emitted vertically.

Optionally, in some embodiments, a light transmissive coating may be provided on each microprism of the array of microprisms 410. In particular, the light-transmissive coating 417 may be disposed on the entrance face of the microprisms. For example, the optically transmissive coating 417 has at least one second entrance face, at least a second exit face, and at least one second support face, the second exit face being parallel to the first entrance face of the microprism. Hereinafter, a specific operation principle of the light-transmitting coating layer 417b on the microprism 410b will be described by taking the light-transmitting coating layer as an example with reference to fig. 16.

In particular, the light-transmitting coating 417b may have a second incident surface 504, a second exit surface 501 (i.e., the incident surface of the microprism), and a second supporting surface 500, where the second incident surface 504 may be parallel to the direction of the display screen or, alternatively, parallel to the exit surface of the microprism. Alternatively, the light-transmitting coating 417b may be grown by coating (e.g., spin, spray, etc.) to provide a light-transmitting coating of the above-described structure.

Return from fingerThe incident light 51 of (a) is incident on the second incident surface 504 of the light-transmitting coating 417b, part of the light is reflected to form reflected light 53, the other light is refracted at the air/light-transmitting coating interface to form refracted light 54, further, the refracted light 54 is refracted at the light-transmitting coating/microprism interface for a second time, and finally, the refracted light 52 is emitted from the first emitting surface 502 of the microprism, if the refracted light 52 is emitted vertically, wherein the incident light 51 forms a first included angle with the direction perpendicular to the second incident surface 504The first incident surface 501 and the first exit surface 502 form a second included angle θ, the refractive light 54 forms a third included angle α with a direction perpendicular to the first incident surface 501, wherein the first included angle, the second included angle, the third included angle, the refractive index n of the light-transmitting coating ₀ Refractive index n of the propagation medium of the incident light 51 ₁ And refractive index n of the microprism ₂ Satisfies the following formula (3):

n ₁ sinα＝n ₂ sin θ equation (3).

In this embodiment, ifThe incident light 51 is incident from air, i.e. n ₁ =1, the refractive index of the high refractive index light-transmitting coating is 2, the refractive index of the material of the microlens is 1.3, and the included angle θ of the microprisms can be determined to be 38.2.

It should be appreciated that in embodiments of the present application, the second incident surface of the light-transmissive coating may be substantially parallel or substantially parallel to the first exit surface of the microprism, and correspondingly, the refracted light 54 may exit substantially perpendicular or substantially perpendicular from the first exit surface of the microprism.

Optionally, in this embodiment, the second incident surface of the light-transmitting coating 417 may be flush with the plane where the highest point of the supporting surface of the microprism is located, or slightly above the plane, or slightly below the plane, that is, the first incident surface of the microprism is provided with a light-transmitting coating that has little effect on the overall thickness of the module.

It should be understood that, in the optical fingerprint device using the light-transmitting coating shown in fig. 16, since the incident surface of the light-transmitting coating is parallel to the display screen, after the micro-prism array is prepared, the light-transmitting coating corresponding to each micro-prism can be uniformly prepared on the incident surface of the micro-prism array, so that the complexity of the preparation process can be reduced.

Alternatively, in this embodiment, the light-transmitting coating layer may be formed by filling a high refractive index inorganic material, for example, zirconia or other inorganic material, in an organic material.

In order to further reduce the reflectivity of the surface of the light-transmitting coating, a layer of anti-reflection coating can be arranged on the incident surface of the light-transmitting coating, so that the light loss of the surface of the light-transmitting coating can be further reduced, and most of light signals can be refracted to enter the light-transmitting coating and then enter the micro-prism array.

Optionally, in some embodiments, the anti-reflection coating may be an anti-reflection film, increasing the transmittance of the optical signal and decreasing the reflectivity of the optical signal.

Through set up the printing opacity coating of high refractive index at the incident surface of microprism array, can make incident light take place twice refraction in this printing opacity coating and microprism, and then follow the perpendicular emergence of exit surface of microprism, under the circumstances of same incident angle, set up the printing opacity coating of high refractive index, be favorable to reducing the contained angle of the incident surface of required microprism and exit surface, thereby can reduce the thickness of module, and set up the printing opacity coating of high refractive index on the microprism and can reduce the reflectivity on microprism surface, reduce the light loss, thereby can shorten exposure duration, promote fingerprint identification speed.

It should be understood that, with respect to the optical fingerprint apparatuses shown in fig. 6, 11 and 15, the optical fingerprint apparatuses shown in fig. 16 to 19 may receive an optical signal incident on the incident surface of the micro prism, which is advantageous for increasing the light receiving area of the optical fingerprint apparatus, where the light receiving area may be the area of the optical fingerprint apparatus that receives the optical signal. For example, for the optical fingerprint device shown in fig. 6, when the incident light is 30 °, the light receiving area of the single microprism is 58.4% of the bottom area of the microprism, when the optical path is adopted for the optical fingerprint device shown in fig. 16, for the same incident angle, under the condition that the refractive index of the light-transmitting coating is 2, the light receiving area of the single microprism is 1.34 times of the bottom area of the microprism, which is about 2.29 times of the light receiving area of the optical fingerprint device shown in fig. 6, so that the signal quantity of the light signal received by the optical sensor is improved, and the exposure time period can be shortened, and the fingerprint identification speed can be improved.

It will be appreciated that without the light transmissive coating, the microprism structure of fig. 8 also has a higher light receiving area than the microprism structure of fig. 7, and thus, for high angle incident light, for exampleAnd the angle of incidence of the incident light is larger than 45 degrees, so that the micro-prism structure shown in fig. 8 is adopted without a light-transmitting coating, and in other embodiments, the light-transmitting coating can be arranged above the micro-prism structure shown in fig. 8, so that the light receiving area is further increased, the exposure time is shortened, and the fingerprint identification speed is increased.

It should be noted that, the thickness of the light-transmitting coating in fig. 16 to 19 is only convenient for illustrating the light path transmission in the light-transmitting coating, and in practical products, the thickness of the light-transmitting coating is very thin, and the thickness of the optical fingerprint device is not greatly affected.

The embodiment of the application further provides an electronic device, as shown in fig. 20, the electronic device 700 may include a display screen 710 and an optical fingerprint device 720, where the optical fingerprint device 720 is disposed below the display screen 710.

Alternatively, the optical fingerprint device 720 may be the optical fingerprint device 40 in the foregoing embodiment, and the specific structure may refer to the foregoing related description, which is not repeated here.

Alternatively, in one embodiment of the present application, the display screen 710 may be a self-luminous display screen (such as an OLED display screen), and includes a plurality of self-luminous display units (such as OLED pixels or OLED light sources). When the optical image acquisition system is a biological feature recognition system, a part of self-luminous display units in the display screen can be used as an excitation light source for biological feature recognition by the biological feature recognition system and used for emitting light signals to the biological feature detection area for biological feature detection.

It should be understood that the specific examples of the embodiments of the present application are intended to facilitate a better understanding of the embodiments of the present application by those skilled in the art, and are not intended to limit the scope of the embodiments of the present application.

It is to be understood that the terminology used in the embodiments of the application and in the appended claims is for the purpose of describing particular embodiments only, and is not intended to be limiting of the embodiments of the application. For example, as used in the embodiments of the application and the appended claims, the singular forms "a," "an," and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise.

Those of ordinary skill in the art will appreciate that the elements of the examples described in connection with the embodiments disclosed herein may be implemented as electronic hardware, computer software, or combinations of both, and that the elements and steps of the examples have been described above generally in terms of functionality for clarity of understanding of interchangeability of hardware and software. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the solution. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present application.

In the several embodiments provided in the present application, it should be understood that the disclosed system and apparatus may be implemented in other manners. For example, the apparatus embodiments described above are merely illustrative, e.g., the division of the units is merely a logical function division, and there may be additional divisions when actually implemented, e.g., multiple units or components may be combined or integrated into another system, or some features may be omitted or not performed. In addition, the coupling or direct coupling or communication connection shown or discussed with each other may be an indirect coupling or communication connection via some interfaces, devices, or elements, or may be an electrical, mechanical, or other form of connection.

The units described as separate units may or may not be physically separate, and units shown as units may or may not be physical units, may be located in one place, or may be distributed on a plurality of network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the embodiment of the present application.

In addition, each functional unit in the embodiments of the present application may be integrated in one processing unit, or each unit may exist alone physically, or two or more units may be integrated in one unit. The integrated units may be implemented in hardware or in software functional units.

The integrated units, if implemented in the form of software functional units and sold or used as stand-alone products, may be stored in a computer readable storage medium. Based on such understanding, the technical solution of the present application is essentially or a part contributing to the prior art, or all or part of the technical solution may be embodied in the form of a software product stored in a storage medium, comprising several instructions for causing a computer device (which may be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the method according to the embodiments of the present application. And the aforementioned storage medium includes: a U-disk, a removable hard disk, a Read-Only Memory (ROM), a random access Memory (RAM, random Access Memory), a magnetic disk, or an optical disk, or other various media capable of storing program codes.

While the application has been described with reference to certain preferred embodiments, it will be understood by those skilled in the art that various changes and substitutions of equivalents may be made and equivalents will be apparent to those skilled in the art without departing from the scope of the application. Therefore, the protection scope of the application is subject to the protection scope of the claims.

Claims

1. An optical fingerprint apparatus for placement under a display screen of an electronic device, comprising:

the incident light conversion structure is arranged below the display screen and is used for converting a first light signal returned from a finger above the display screen into a second light signal, and the incident light conversion structure comprises a micro prism array, wherein the micro prism array comprises a plurality of micro prism units, the first light signal is a light signal inclined relative to the display screen, and the second light signal is a light signal vertical relative to the display screen;

the optical component is arranged below the incident light conversion structure and is used for receiving the second optical signal and transmitting the second optical signal to the optical sensor, and the optical sensor comprises a micro lens array;

the optical sensor comprises an optical sensing array, wherein the optical sensing array comprises a plurality of optical sensing units, is arranged below the optical assembly and is used for receiving optical signals transmitted by the optical assembly, and the optical signals are used for acquiring fingerprint information of the finger;

the projection area of each micro prism in the micro prism unit on the plane of the optical sensing array is equal to the projection area of each micro lens in the micro lens array on the plane of the optical sensing array.

2. The optical fingerprint device according to claim 1, wherein each microprism unit comprises at least one microprism, each microprism comprising at least one first entrance face and at least one first exit face, the first entrance face being inclined with respect to the plane of the display screen, the first exit face being parallel to the plane of the display screen.

3. The optical fingerprint device according to claim 2, wherein each of the microprism units comprises a microprism, and an optical sensing unit or a row of optical sensing units are disposed under one microprism; or (b)

4. An optical fingerprint device according to claim 3, wherein the entrance facets of said plurality of microprisms are oriented differently with respect to the plane of said optical sensor.

5. The optical fingerprint device according to claim 4, wherein the plurality of microprisms includes four microprisms, the entrance faces of adjacent ones of the four microprisms being 90 degrees apart from the direction angle of the optical sensor.

6. An optical fingerprint device according to any one of claims 2-5, wherein said first optical signal forms a first angle with a direction perpendicular to said optical sensorThe first incident surface and the first emergent surface of each microprism form a second included angle theta, wherein the first included angle +.>The second included angle theta, the refractive index n of the propagation medium of the first optical signal ₁ Refractive index n of the microprism ₂ The following relationship is satisfied:

7. an optical fingerprint device according to any one of claims 2-5, wherein each micro-prism comprises at least one first support surface provided with a reflective layer.

8. The optical fingerprint device according to claim 7, wherein the first light signal is incident on the first incident surface and enters the microprism to form a third light signal, the third light signal is incident on the first incident surface again after being reflected by the first supporting surface, and the second light signal is formed to be emitted vertically after being reflected again from the first incident surface, wherein the first light signal forms a first angle with a direction perpendicular to the optical sensor The first incident surface and the first emergent surface of each microprism form a second included angle theta, the third optical signal forms a third included angle alpha with the direction vertical to the first incident surface, and the third optical signal forms a fourth included angle beta with the direction parallel to the first emergent surface, wherein the first included angle->The second included angle theta, the third included angle alpha, the fourth included angle beta, the refractive index n of the propagation medium of the first optical signal ₁ Refractive index n of the microprism ₂ The following relationship is satisfied:

β＝(90°-θ)+α

θ＝(90°-θ)+β。

9. the optical fingerprint device according to any one of claims 2 to 5, further comprising:

10. The optical fingerprint device according to claim 9, wherein said second exit surface is parallel to an entrance surface of said incident light conversion structure, said second entrance surface is parallel to an exit surface of said incident light conversion structure, and said first optical signal forms a first angle with a direction perpendicular to said second entrance surface The incident surface of the incident light conversion structure and the emergent surface of the incident light conversion structure form a second included angle theta, and the fourth optical signal and the direction perpendicular to the incident surface of the incident light conversion structure form a third included angle alpha, wherein the first included angle>The second included angle theta, the third included angle alpha and the refractive index n of the light-transmitting coating ₀ Refractive index n of the propagation medium of the first optical signal ₁ And refractive index n of the microprism ₂ The following relationship is satisfied:

n ₁ sinα＝n ₂ sinθ。

11. the optical fingerprint device according to claim 9, wherein the light-transmitting coating is prepared on the incident surface of the incident light conversion structure by spin coating or spray coating.

12. An optical fingerprint device according to claim 9, wherein said at least one second entrance face of said light transmissive coating is provided with an anti-reflection coating for reducing the reflectivity of said first optical signal at said at least one second entrance face and/or a polarizing coating for selecting the polarization direction of said first optical signal.

13. The optical fingerprint device according to any one of claims 1-5, wherein said optical assembly further comprises at least one light blocking layer disposed below said microlens array, each of said at least one light blocking layer having an aperture disposed therein;

14. The optical fingerprint device according to claim 13, wherein the at least one light blocking layer includes a first light blocking layer therein, the first light blocking layer being disposed at a back focal plane position of the microlens array.

15. The optical fingerprint device according to claim 14, wherein the first light blocking layer is a metal layer of the optical sensor.

16. The optical fingerprint device according to claim 13, wherein the optical assembly further comprises:

a filter provided at least one of the following positions:

the incident light conversion structure and the microlens array;

between the microlens array and the optical sensor.

17. The optical fingerprint device according to any one of claims 1-5, wherein the optical assembly comprises a straight-hole collimator comprising a plurality of straight-holes, each optical sensing unit in the optical sensor corresponding to at least one of the straight-hole collimators, wherein the straight-hole collimator is configured to receive the second optical signal converted by the incident light conversion structure and transmit the second optical signal to the plurality of optical sensing units through the collimating holes in the straight-hole collimator.

18. The optical fingerprint device according to claim 17, wherein the straight hole alignment unit is formed by a metal layer and a metal via layer of the optical sensing unit.

19. The optical fingerprint device according to claim 17, wherein the optical assembly further comprises:

a filter provided at least one of the following positions:

20. The optical fingerprint device according to any one of claims 1 to 5, wherein the optical fingerprint device utilizes a portion of a display unit of the display screen as an excitation light source for optical fingerprint detection.

21. An electronic device, comprising:

a display screen;

the optical fingerprint device of any one of claims 1-20, wherein the optical fingerprint device is disposed below the display screen.

22. The electronic device of claim 21, wherein the display screen is an organic light emitting diode, OLED, display screen comprising a plurality of OLED light sources, wherein the optical fingerprint device employs at least a portion of the OLED light sources as excitation light sources for optical fingerprint detection.