CN111108509B

CN111108509B - Fingerprint detection device and electronic equipment

Info

Publication number: CN111108509B
Application number: CN201980004232.5A
Authority: CN
Inventors: 姚国峰; 沈健; 纪登鑫
Original assignee: Shenzhen Goodix Technology Co Ltd
Current assignee: Shenzhen Goodix Technology Co Ltd
Priority date: 2019-08-08
Filing date: 2019-08-08
Publication date: 2023-09-08
Anticipated expiration: 2039-08-08
Also published as: CN211349375U; WO2021022560A1; CN111108509A; WO2021022596A1

Abstract

There is provided a fingerprint detection device adapted for use with an electronic device having a display screen to enable off-screen optical fingerprint detection, comprising: a microprism array arranged below the display screen; an optical assembly disposed below the array of microprisms; the optical sensing unit array is arranged below the optical assembly and comprises at least one optical sensing unit arranged below each micro prism in the micro prism array. The micro-prism array converts the optical signals reflected by the finger and inclined relative to the display screen into signals perpendicular to the display screen, so that the optical loss of the optical signals reflected by the finger in the transmission process can be reduced, and the signal quantity and the fingerprint identification effect received by the optical sensing unit array are improved. Furthermore, since the thickness of the micro prism array is generally thin, the thickness of the fingerprint detection device can be ensured to be small.

Description

Fingerprint detection device and electronic equipment

Technical Field

The embodiment of the application relates to the field of fingerprint detection, and more particularly relates to a fingerprint detection 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. However, in some cases, for example, in the case of a dry finger, the contact area between the dry finger and the display screen is very small, the recognition response area is very small, the acquired fingerprint is discontinuous, the feature points are easy to lose, and the performance of fingerprint recognition is affected.

Therefore, how to improve the fingerprint recognition performance becomes a technical problem to be solved.

Disclosure of Invention

Provided are a fingerprint detection device and an electronic device capable of improving fingerprint recognition performance.

In a first aspect, a fingerprint detection apparatus is provided, suitable for use in an electronic device having a display screen to enable off-screen optical fingerprint detection, comprising:

a microprism array arranged below the display screen;

An optical assembly disposed below the array of microprisms;

an optical sensing unit array disposed below the optical assembly, the optical sensing unit array including at least one optical sensing unit disposed below each of the microprisms in the microprism array;

the first optical signal returned from the finger above the display screen is converted into a second optical signal through the micro-prism array, the second optical signal transmits the second optical signal converted by each micro-prism in the micro-prism array to at least one optical sensing unit arranged below the same micro-prism through the optical assembly, the first optical signal is an optical signal inclined relative to the display screen, and the second optical signal is an optical signal vertical relative to the display screen;

the optical signals received by the optical sensing unit array are used for detecting fingerprint information of the finger.

The micro-prism array converts the optical signals reflected by the finger and inclined relative to the display screen into signals perpendicular to the display screen, so that the optical loss of the optical signals reflected by the finger in the transmission process can be reduced, and the signal quantity and the fingerprint identification effect received by the optical sensing unit array are improved.

Furthermore, since the thickness of the micro prism array is generally thin, the thickness of the fingerprint detection device can be ensured to be small.

In some possible implementations, each micro prism in the array of micro prisms includes at least one entrance face for receiving the first optical signal and one exit face for emitting the second optical signal, wherein each of the at least one entrance face is a plane tilted with respect to the display screen, and the one exit face is a plane parallel with respect to the display screen.

In some possible implementations, the first optical signal forms a first included angle with a direction perpendicular to the display screen;

the second included angle formed by the incident surface and the emergent surface of each micro prism in the micro prism array is:

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

In some possible implementations, the first included angle is greater than or equal to 20 degrees.

In some possible implementations, an optical sensing unit is disposed below each entrance face of each micro prism of the array of micro prisms.

In some possible implementations, the micro-prism array includes a plurality of micro-prism units distributed in an array, each of the plurality of micro-prism units including a plurality of micro-prisms distributed in central symmetry.

In some possible implementations, each of the plurality of microprismatic units comprises 4 microprismatic.

In some possible implementations, the array of microprisms includes a plurality of microprisms distributed in an array.

In some possible implementations, a plurality of optical sensing units are disposed below each entrance face of each microprism in the array of microprisms.

In some possible implementations, the micro prism array includes a plurality of micro prisms arranged along a first direction, and a plurality of optical sensing units arranged along a second direction are disposed below each incident surface of each micro prism of the plurality of micro prisms, and the first direction is perpendicular to the second direction.

In some possible implementations, each microprism in the array of microprisms is any one of:

right angle triangular prism, isosceles triangular prism, right angle trapezoidal prism and isosceles trapezoidal prism.

In some possible implementations, the optical assembly includes:

a micro lens array disposed below the micro prism array;

the light blocking layers are arranged between the micro lens array and the optical sensing unit array, and openings corresponding to each optical sensing unit in the optical sensing unit array are arranged in each light blocking layer of the at least one light blocking layer;

the micro lens array is used for receiving the second optical signal converted by the micro prism array and transmitting the second optical signal to the optical sensing unit array through the opening of the at least one light blocking layer.

Compared with the scheme of converging inclined light signals directly through the micro lenses, the micro prism array converts light signals which are reflected by fingers and are inclined relative to the display screen into signals which are vertical relative to the display screen, and then the micro lenses and the micropore diaphragms are used as optical components to converge vertical light signals, so that shadow areas of the micro lenses are not existed, and the signal quantity and the fingerprint identification effect which can be received by the optical sensing unit array are improved.

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

In some possible implementations, the bottom light blocking layer is a metal wiring layer of the array of optical sensing cells.

In some possible implementations, the at least one light blocking layer includes a plurality of light blocking layers, and openings in each light blocking layer corresponding to the same microlens sequentially decrease in aperture from top to bottom.

In some possible implementations, the optical component is a straight-hole collimator, and each optical sensing unit in the array of optical sensing units corresponds to at least one collimating hole in the straight-hole collimator; the straight hole collimator is used for receiving the second optical signal converted by the micro prism array and transmitting the second optical signal to the optical sensing unit array through the collimating holes in the straight hole collimator.

Compared with the scheme of screening optical signals directly through the inclined hole collimator, the micro prism array is used for converting optical signals which are reflected by fingers and are inclined relative to the display screen into signals which are vertical to the display screen, and then the straight hole collimator is used for screening the optical signals, so that the manufacturing difficulty and cost of the collimator are effectively reduced.

In some possible implementations, the array of optical sensing units and the straight-hole collimator are integrally arranged.

In some possible implementations, the fingerprint detection device further includes:

a filter provided at least one of:

above the microprism array;

the microprism array and the optical assembly;

an interior of the optical assembly; and

the optical component and the optical sensing unit array.

Compared with the inclined optical signal directly passing through the optical filter, the optical loss of the vertical optical signal is small when only the optical filter is arranged, and the optical filter is not required to be customized, so that the manufacturing complexity of the vertical optical signal is reduced.

In a second aspect, a terminal device is provided, including a display screen and the fingerprint detection device according to the first aspect.

Drawings

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

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

Fig. 3 is another schematic structural diagram of an electronic device to which the present application can be applied.

Fig. 4 is a schematic cross-sectional view of the electronic device shown in fig. 3.

Fig. 5 shows a schematic diagram of a fingerprint detection device according to an embodiment of the present application.

Fig. 6 shows a schematic structural diagram of another fingerprint detection device according to an embodiment of the present application.

Fig. 7 shows a schematic cross-sectional view of a further fingerprint detection device according to an embodiment of the present application.

Fig. 8 is a schematic diagram showing a process of changing the incident direction of light by the microprism of the embodiment of the present application.

Fig. 9 is a perspective view of the microprism array of fig. 7.

Fig. 10 is a schematic structural view of the fingerprint detection device shown in fig. 7 in a plan view.

Fig. 11 is a schematic diagram of a modified structure of the fingerprint detection device shown in fig. 7.

Fig. 12 and 13 are plan views of the microprism unit shown in fig. 11.

Fig. 14 is a schematic structural view of a field of view of a fingerprint detection device according to an embodiment of the present application.

Fig. 15 is another schematic view of a modified structure of the fingerprint detection device shown in fig. 7.

Detailed Description

The technical scheme of the application will be described below with reference to the accompanying drawings.

The technical scheme of the embodiment of the application can be applied to various electronic equipment. For example, smart phones, notebook computers, tablet computers, gaming devices, and other portable or mobile computing devices, as well as electronic databases, automobiles, bank automated teller machines (Automated Teller Machine, ATM), and other electronic devices. However, the embodiment of the present application is not limited thereto.

The technical scheme of the embodiment of the application can be used for the biological characteristic recognition technology. The biometric technology includes, but is not limited to, fingerprint recognition, palm print recognition, iris recognition, face recognition, living body recognition, and the like. For ease of explanation, fingerprint recognition techniques are described below as examples.

The technical scheme of the embodiment of the application can be used for the under-screen fingerprint identification technology and the in-screen fingerprint identification technology.

The under-screen fingerprint identification technology is characterized in that the fingerprint identification module is arranged below the display screen, so that fingerprint identification operation is carried out in the display area of the display screen, and a fingerprint acquisition area is not required to be arranged in an area except the display area on the front side of the electronic equipment. Specifically, the fingerprint recognition module uses light returned from the top surface of the display assembly of the electronic device for fingerprint sensing and other sensing operations. This returned light carries information about an object (e.g., a finger) in contact with or in proximity to the top surface of the display assembly, and the fingerprint recognition module located below the display assembly performs off-screen fingerprint recognition by capturing and detecting this returned light. The fingerprint recognition module can be designed to realize expected optical imaging by properly configuring optical elements for collecting and detecting returned light, so as to detect fingerprint information of the finger.

Correspondingly, the In-screen (In-display) fingerprint identification technology refers to that a fingerprint identification module or a part of fingerprint identification modules are arranged inside a display screen, so that fingerprint identification operation is carried out In a display area of the display screen, and a fingerprint acquisition area is not required to be arranged In an area except the display area on the front side of the electronic equipment.

It should be noted that, for convenience of explanation, like reference numerals denote like components in the embodiments of the present application, and detailed descriptions of the like components are omitted in the different embodiments for brevity. It should be understood that the thickness, length, width, etc. dimensions of the various components in the embodiments of the application shown in the drawings, as well as the overall thickness, length, width, etc. dimensions of the integrated device, are merely illustrative and should not be construed as limiting the application in any way.

Fig. 1 to 4 show schematic diagrams of electronic devices to which embodiments of the present application may be applied. Fig. 1 and 3 are schematic diagrams illustrating the orientation of the electronic device 10, and fig. 2 and 4 are schematic diagrams illustrating the cross-section of the electronic device 10 illustrated in fig. 1 and 3, respectively.

Referring to fig. 1 to 4, the electronic device 10 may include a display 120 and an optical fingerprint recognition module 130.

The display screen 120 may be a self-luminous display screen employing a display unit having self-luminescence as display pixels. For example, the display 120 may be an Organic Light-Emitting Diode (OLED) display or a Micro-LED (Micro-LED) display. In other alternative embodiments, the display 120 may be a liquid crystal display (Liquid Crystal Display, LCD) or other passive light emitting display, which is not limited in this regard. Further, the display screen 120 may be specifically a touch display screen, which not only can perform screen display, but also can detect touch or press operation of a user, so as to provide a personal computer interaction interface for the user. For example, in one embodiment, the electronic device 10 may include a Touch sensor, which may be specifically a Touch Panel (TP), which may be disposed on the surface of the display screen 120, or may be partially integrated or entirely integrated into the display screen 120, so as to form the Touch display screen.

The optical fingerprint module 130 includes an optical fingerprint sensor including a sensing array 133 having a plurality of optical sensing units 131 (which may also be referred to as photosensitive pixels, pixel units, etc.). The sensing area of the sensing array 133 or the sensing area thereof is the fingerprint detection area 103 (also referred to as a fingerprint collection area, a fingerprint identification area, etc.) of the optical fingerprint module 130.

The optical fingerprint module 130 is disposed in a local area below the display screen 120.

With continued reference to fig. 1, the fingerprint detection area 103 may be located within a display area of the display 120. In an alternative embodiment, the optical fingerprint module 130 may be disposed at other locations, such as a side of the display screen 120 or an edge non-transparent area of the electronic device 10, and the optical signal from at least a portion of the display area of the display screen 120 is guided to the optical fingerprint module 130 through an optical path design, so that the fingerprint detection area 103 is actually located in the display area of the display screen 120.

For the electronic device 10, when the user needs to unlock the electronic device 10 or perform other fingerprint verification, the user only needs to press the finger on the fingerprint detection area 103 located on the display screen 120, so as to realize 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.

With continued reference to fig. 2, the optical fingerprint module 130 may include a light detecting portion 134 and an optical component 132. The light detecting section 134 includes the sensing array 133 (may also be referred to as an optical fingerprint sensor) and a reading circuit and other auxiliary circuits electrically connected to the sensing array 133, which may be fabricated on a chip (Die) such as an optical imaging chip or an optical fingerprint sensor by a semiconductor process. The sensing array 133 is specifically a Photo detector (Photo detector) array, which includes a plurality of Photo detectors distributed in an array, which may be used as an optical sensing unit as described above. The optical component 132 may be disposed above the sensing array 133 of the light detecting portion 134, and may specifically include a Filter layer (Filter), a light guiding layer or a light path guiding structure, and other optical elements, where the Filter layer may be used to Filter out ambient light penetrating the finger, and the light guiding layer or the light path guiding structure is mainly used to guide reflected light reflected from the finger surface to the sensing array 133 for optical detection.

In some embodiments of the application, 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 detection portion 134, or the optical component 132 may be disposed outside the chip in which the optical detection 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.

In some embodiments of the present application, the area or the light sensing range of the sensing array 133 of the optical fingerprint module 130 corresponds to the fingerprint detection area 103 of the optical fingerprint module 130. The fingerprint collection area 103 of the optical fingerprint module 130 may be equal to or different from the area or the light sensing range of the area where the sensing array 133 of the optical fingerprint module 130 is located, which is not particularly limited in the embodiment of the present application.

For example, the fingerprint detection area 103 of the optical fingerprint module 130 may be designed to be substantially identical to the area of the sensing array of the optical fingerprint module 130 by performing light path guidance through light collimation.

For another example, the area of the fingerprint detection area 103 of the optical fingerprint module 130 may be larger than the area of the sensing array 133 of the optical fingerprint module 130, 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 optical assembly 132 may include an optical path guiding structure as exemplified below.

Taking the optical path guiding structure as an example, an optical Collimator with a through hole array having a high aspect ratio is adopted as the optical Collimator, the optical Collimator can be specifically a Collimator (Collimator) layer manufactured on a semiconductor silicon wafer, the optical Collimator is provided with a plurality of collimating units or micropores, the collimating units can be specifically small holes, light vertically incident to the collimating units in reflected light reflected by fingers can pass through and be received by sensor chips below the collimating units, and light with an overlarge incident angle is attenuated in the collimating units through repeated reflection, so that each sensor chip basically only can receive the reflected light reflected by fingerprint lines right above the sensor chips, the image resolution can be effectively improved, and further the fingerprint identification effect is improved. The optical collimator may include a straight-hole collimator and an inclined-hole collimator, wherein an axial direction of the collimating unit or the micro-hole in the straight-hole collimator may be perpendicular to the sensing array 133 of the optical fingerprint module 130, and an axial direction of the collimating unit or the micro-hole in the inclined-hole collimator may be inclined with respect to the sensing array 133 of the optical fingerprint module 130.

Taking the optical path design of the optical Lens as the optical path guiding structure, the optical path guiding structure may be an optical Lens (Lens) layer having one or more Lens units, such as a Lens group composed of one or more aspheric lenses, for converging the reflected light reflected from the finger to the sensing array 133 of the light detecting part 134 thereunder, so that the sensing array 133 may image based on the reflected light, thereby obtaining a fingerprint image of the finger. Further, the optical lens layer may further be formed with a pinhole or a micropore diaphragm in the optical path of the lens unit, for example, one or more light shielding sheets may be formed in the optical path of the lens unit, wherein at least one light shielding sheet may be formed with a light-transmitting micropore in the optical axis or the optical center area of the lens unit, and the light-transmitting micropore may serve as the pinhole or micropore diaphragm. The pinhole or the microporous diaphragm may be matched with the optical lens layer and/or other optical film layers above the optical lens layer, so as to enlarge the field of view of the optical fingerprint module 130, so as to improve the fingerprint imaging effect of the optical fingerprint module 130.

Taking an optical path design in which the optical path guiding structure employs a Micro-Lens layer as an example, the optical path guiding structure may be a Micro-Lens array including a plurality of Micro-lenses, which may be formed over the sensing array 133 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 133, respectively. And other optical film layers, such as a dielectric layer or a passivation layer, can be formed between the microlens layer and the sensing unit. More specifically, a light blocking layer (or referred to as a light blocking layer, etc.) having micro holes (or referred to as openings) formed between its corresponding micro lens and sensing unit may be further included between the micro lens layer and the sensing unit, and the light blocking layer may block optical interference between adjacent micro lenses and sensing unit, and allow light corresponding to the sensing unit to be condensed into the micro holes by the micro lenses 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 optical path guiding structure may be used alone or in combination.

For example, a microlens layer may be further provided above or below the collimator layer or the optical lens layer. Of course, when the collimator layer or the optical lens layer is used in combination with the microlens layer, the specific laminated structure or the optical path thereof may need to be adjusted according to actual needs.

On the other hand, the optical component 132 may further include other optical elements, such as a Filter layer (Filter) or other optical film, which may be disposed between the optical path guiding structure and the optical fingerprint sensor or between the display screen 120 and the optical path guiding structure, and is mainly used to isolate the influence of the external interference light on the optical fingerprint detection. The optical filter may be used to filter out ambient light that penetrates through the finger and enters the optical fingerprint sensor through the display screen 120, similar to the optical path guiding structure, and the optical filter may be separately configured for each optical fingerprint sensor to filter out interference light, or may also use a large-area optical filter to cover the plurality of optical fingerprint sensors simultaneously.

The fingerprint recognition module 140 may be configured to collect fingerprint information (such as fingerprint image information) of a user.

Taking the display screen 120 as an example, a display screen having a self-luminous display unit, such as an Organic Light-Emitting Diode (OLED) display screen or a Micro-Light-Emitting Diode (Micro-LED) display screen, is adopted. The optical fingerprint module 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 the finger 140 is pressed against the fingerprint detection area 103, the display 120 emits a beam of light 111 towards the target finger 140 above the fingerprint detection area 103, which light 111 is reflected at the surface of the finger 140 to form reflected light or scattered inside the finger 140 to form scattered light (transmitted light). In the related patent application, the above reflected light and scattered light are collectively referred to as reflected light for convenience of description. Since the ridge (ridge) 141 and the valley (valley) 142 of the fingerprint have different light reflection capacities, the reflected light 151 from the ridge and the reflected light 152 from the valley have different light intensities, and the reflected light is received by the sensing array 133 in the optical fingerprint module 130 and converted into corresponding electrical signals, i.e. fingerprint detection signals after passing through the optical component 132; 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 alternatives, the optical fingerprint module 130 may also use an internal light source or an external light source to provide an optical signal for fingerprint detection and identification. In this case, the optical fingerprint module 130 may be applied to not only a self-luminous display screen such as an OLED display screen, but also 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, to support the under-screen fingerprint detection of the liquid crystal display, the optical fingerprint system of the electronic device 10 may further include an excitation light source for optical fingerprint detection, where the excitation light source may be specifically an infrared light source or a light source of non-visible light with a specific wavelength, which may be disposed below the backlight module of the liquid crystal display or an edge region below a protective cover plate of the electronic device 10, and the optical fingerprint module 130 may be disposed below 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 module 130; alternatively, the optical fingerprint module 130 may be disposed below the backlight module, and the backlight module may be configured to allow the fingerprint detection light to pass through the liquid crystal panel and the backlight module and reach the optical fingerprint module 130 by making holes or other optical designs on the film layers such as the diffusion sheet, the brightness enhancement sheet, and the reflection sheet. When the optical fingerprint module 130 is used to provide an optical signal for fingerprint detection using an internal light source or an external light source, the detection principle is consistent with the above description.

In a specific implementation, the electronic device 10 may further include a transparent protective cover plate, which may be a glass cover plate or a sapphire cover plate, located above the display screen 120 and covering the front surface of the electronic device 10. Thus, in the embodiment of the present application, the pressing of the finger against the display screen 120 actually means pressing the cover plate above the display screen 120 or the surface of the protective layer covering the cover plate.

On the other hand, the optical fingerprint module 130 may include only one optical fingerprint sensor, and at this time, the area of the fingerprint detection area 103 of the optical fingerprint module 130 is smaller and the position is fixed, so that the user needs to press the finger to a specific position of the fingerprint detection area 103 when inputting the fingerprint, otherwise, the optical fingerprint module 130 may not be able to collect the fingerprint image, which may result in poor user experience. In other alternative embodiments, the optical fingerprint module 130 may specifically include a plurality of optical fingerprint sensors. The optical fingerprint sensors may be disposed side by side below the display screen 120 in a spliced manner, and the sensing areas of the optical fingerprint sensors together form the fingerprint detection area 103 of the optical fingerprint module 130. Thus, the fingerprint detection area 103 of the optical fingerprint module 130 can be extended to the main area of the lower half of the display screen, that is, to the finger usual pressing area, thereby realizing the blind press type fingerprint input operation. Further, when the number of the optical fingerprint sensors is sufficient, the fingerprint detection area 103 may be further extended to a half display area or even the whole display area, so as to implement half-screen or full-screen fingerprint detection.

Referring to fig. 3 and 4, the optical fingerprint module 130 in the electronic device 10 may include a plurality of optical fingerprint sensors, which may be disposed side by side under the display screen 120 by, for example, splicing, and the sensing areas of the plurality of optical fingerprint sensors together form the fingerprint detection area 103 of the optical fingerprint device 130.

Further, the optical component 132 may include a plurality of optical path guiding structures, where each optical path guiding structure corresponds to one optical fingerprint sensor (i.e. the sensing array 133) and is respectively disposed above the corresponding optical fingerprint sensor in a fitting manner. Alternatively, the plurality of optical fingerprint sensors may share a unitary light path guiding structure, i.e. the light path guiding structure has a sufficiently large area to cover the sensing array of the plurality of optical fingerprint sensors.

Taking the optical assembly 132 as an example, an optical collimator having a through hole array with a high aspect ratio is used, when the optical fingerprint module 130 includes a plurality of optical fingerprint sensors, one or more collimating units may be configured for one optical sensing unit in the optical sensing array of each optical fingerprint sensor, and the collimating units are attached to and disposed above the corresponding optical sensing units. Of course, the plurality of optical sensing units may also share one collimating unit, i.e. the one collimating unit has a sufficiently large aperture to cover the plurality of optical sensing units. Because one collimating unit can correspond to a plurality of optical sensing units or one optical sensing unit corresponds to a plurality of collimating units, the correspondence between the space period of the display screen 120 and the space period of the optical fingerprint sensor is destroyed, and therefore, even if the space structure of the luminous display array of the display screen 120 is similar to that of the optical sensing array of the optical fingerprint sensor, the optical fingerprint module 130 can be effectively prevented from generating moire fringes by utilizing the optical signals passing through the display screen 120 to perform fingerprint imaging, and the fingerprint recognition effect of the optical fingerprint module 130 is effectively improved.

Taking the optical component 132 as an example, when the optical fingerprint module 130 includes a plurality of sensor chips, one optical lens may be configured for each sensor chip to perform fingerprint imaging, or one optical lens may be configured for a plurality of sensor chips to perform light convergence and fingerprint imaging. Even when one sensor chip has two sensing arrays (Dual Array) or multiple sensing arrays (Multi-Array), two or more optical lenses may be configured for the sensor chip to perform optical imaging in cooperation with the two or more sensing arrays, so as to reduce the imaging distance and enhance the imaging effect.

It should be understood that fig. 1-4 are only examples of the present application and should not be construed as limiting the present application.

For example, the number, size and arrangement of the fingerprint sensors are not particularly limited, and can be adjusted according to actual requirements. For example, the number of the fingerprint sensors of the optical fingerprint module 130 may be 2, 3, 4 or 5, and the fingerprint sensors may be distributed in a square or circular shape.

The optical fingerprint module 130 may detect fingerprint information by using an optical signal perpendicular to the display screen 120, or may detect fingerprint information by using an optical signal oblique to the display screen 120, which is not limited in particular in the embodiment of the present application.

A fingerprint detection device for detecting fingerprint information based on oblique optical signals according to an embodiment of the present application will be described with reference to fig. 5 and 6. Fig. 5 shows a schematic diagram of a fingerprint detection device 20 according to an embodiment of the present application. Fig. 6 shows a schematic structural diagram of a fingerprint detection device 30 according to an embodiment of the present application. Both the fingerprint detection device 20 shown in fig. 5 and the fingerprint detection device 30 shown in fig. 6 are suitable for the electronic apparatus 10 shown in fig. 1 to 4, or the fingerprint detection device 20 or the fingerprint detection device 30 may be the optical fingerprint module 130 shown in fig. 1 to 4.

As an example, referring to fig. 5, 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, a photosensitive unit 23 disposed below the 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 light transmittance to the visible light wave band, and cuts off the infrared light, so that the finger reflected light has the function of preventing the infrared wave band light in the sunlight from penetrating through the finger, and the fingerprint image acquisition is interfered. The reflected light 24 then passes through the microlens 21 and is converged to a point F on the microlens back focal plane 211 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 material of the microlens 21. The microporous diaphragm 22 is arranged at F ₁ At the region other than the microporous diaphragm 22, a non-light-transmitting layer 220 is provided, the size of the diaphragm aperture determining the angular range of the incident light that can passOnly the incident angle is +.>To->The light 24 reflected by the finger in the range can reach the photosensitive 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. 5 faces two problems: firstly, the transmittance of the optical filter 25 for large-angle oblique incident light is reduced relative to that of normal incident light; secondly, a partial region (e.g., region 241 in fig. 5) of the microlens 21 cannot exhibit a converging effect due to a shadow effect (lens shading effect).

These two points will result in a large light loss when the fingerprint detection device 20 receives the light with a large angle and oblique incidence, so that a sufficient signal quantity must be obtained by extending the exposure time of the fingerprint detection device 20, but this will result in a long fingerprint recognition space, which affects the user experience.

As another example, referring to fig. 6, the fingerprint detection device 30 may include a filter 35, a tilted-hole collimator 36 (including a plurality of tilted holes 361) disposed below the filter 35, and a photosensitive unit 33 below the tilted-hole collimator 36. Because the included angle between the direction of the inclined hole 361 and the direction of the normal line 310 is preset to beTherefore, the photosensitive unit 33 can only receive the reflected light 34 of the finger at the incident angle +.>Or approach->Is provided.

However, the solution shown in fig. 6 still has a problem that the transmittance of the filter 35 is low.

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.

The embodiment of the application can be applied to detection of various fingers, and particularly can be applied to detection of dry fingers. By dry finger, it is meant a relatively dry finger. The existing fingerprint identification scheme has poor fingerprint identification effect on the dry finger, and the fingerprint identification scheme provided by the embodiment of the application can improve the fingerprint identification performance on the dry finger.

Particularly, the embodiment of the application solves the problem of light loss when the fingerprint detection device 20 and the fingerprint detection device 30 receive the incident light with a large angle, thereby shortening the exposure time of the fingerprint detection device, accelerating the fingerprint identification speed and improving the user experience.

The embodiment of the application is suitable for the lower part of the display screen to realize the detection of the optical fingerprint under the screen. Fig. 7 shows a schematic diagram of a fingerprint detection device 40 according to an embodiment of the present application. The fingerprint detection device 40 may be adapted to the electronic apparatus 10 shown in fig. 1-4, or the device 40 may be an optical fingerprint module 130 shown in fig. 1-4.

Referring to fig. 7, the fingerprint detection device 40 may include a light guiding portion 41 and a light detecting portion 42. Wherein the light guiding portion 41 may be used to guide the light signal reflected via the finger to the light detecting portion 42. The light guiding part 41 may be included as a micro prism array 410, which may include a plurality of micro prisms (micro-prisms), such as a first micro prism 410a, a second micro prism 410b, and a third micro prism 410c. 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 upper surface of the light detecting portion 42, and the second optical signal may be an optical signal perpendicular with respect to the upper surface of the light detecting portion 42.

With continued reference to fig. 7, the light detecting portion 42 may include an optical sensing unit array 424, which may include a plurality of optical sensing units. For example, the optical sensing unit 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 unit array 424 is used to detect fingerprint information of the finger. Wherein 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 below the first micro prism 410a, at least a second optical sensing unit 424b is disposed below the second micro prism 410b, and at least a third optical sensing unit 424c is disposed below the third micro prism 410 c.

Further, the light detecting portion 42 may further include a metal layer 421 and a dielectric layer 423 between the metals 421. The metal layer 421 may be a metal wiring layer of the optical sensing unit array 424, and is used for electrically interconnecting optical sensing units in the optical sensing unit array 424 and electrically connecting the optical sensing unit array 424 to an external device, so as to implement internal and external communication of the fingerprint detection device 40.

Of course, the optical detection portion may include a plurality of metal layers 421. For example, the light detecting part 42 may include three metal layers 421, a dielectric layer 423 may be disposed between the three metal layers 421 and between the metal layers 421 and the optical sensing unit array 424, and a material of the dielectric layer 423 may be a transparent material.

In some embodiments of the present application, the light guiding portion 41 may further include an optical component (e.g., the optical component 132 shown in fig. 1 or fig. 2) disposed between the micro prism array 410 and the optical sensing unit array 424, for screening or separating the second optical signal converted by the micro prism array 410. That is, the optical component may be used to screen out a part of the optical signal from the second optical signal converted by the micro prism array 410 and guide the part of the optical signal to a specific optical sensing unit in the optical sensing unit array 424.

For example, the optical assembly is used to direct the second optical signal converted by each micro-prism to an optical sensing unit under the same micro-prism. That is, after the first optical signal returned from the finger above the display screen is converted into the second optical signal by the micro prism array 410, the second optical signal is transmitted to at least one optical sensing unit disposed below the same micro prism by the optical component, where the second optical signal is converted by each micro prism in the micro prism array 410. For example, the optical component may be configured to guide the second optical signal converted by the first micro prism 410a to the first optical sensing unit 424a, may be configured to guide the second optical signal converted by the second micro prism 410b to the second optical sensing unit 424b, and may be configured to guide the second optical signal converted by the third micro prism 410c to the third optical sensing unit 424c.

Based on the above technical solution, the micro prism array 410 converts the optical signal reflected by the finger and inclined relative to the display screen into the signal perpendicular to the display screen, so as to reduce the optical loss of the optical signal reflected by the finger during the transmission process, and improve the signal quantity and fingerprint recognition effect received by the optical sensing unit array 424.

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

Of course, the optical component may also guide the second optical signal converted by each micro prism in the micro prism array 410 to a position obliquely below the same micro prism, so as to reduce the thickness of the fingerprint detection device 40. For example, the optical assembly may be used to direct the second optical signal converted by the first micro-prism 410a to the second optical sensing unit 424b, i.e., the optical sensing unit below the second micro-prism 410 b. The embodiment of the present application is not particularly limited thereto.

With continued reference to fig. 7, the optical assembly may employ a microlens array and at least one light blocking layer, wherein the microlens array may be disposed below the microprism array 410 and include a plurality of microlenses; the at least one light blocking layer may be disposed between the microlens array and the optical sensing unit array 424, and each of the at least one light blocking layer is provided with a plurality of openings corresponding to the plurality of optical sensing units; wherein the optical sensing unit array 424 is used for receiving the optical signals converged by the microlens array and transmitted through the openings of the at least one light blocking layer. Or the microlens array is configured to receive the second optical signal converted by the microprism array 410 and transmit the second optical signal to the optical sensing unit array 424 through the opening of the at least one light blocking layer.

As an example, the microlens array may include a first microlens 412a, a second microlens 412b, and a third microlens 412c. The at least one light blocking layer includes a first light blocking layer 414 and a second light blocking layer, wherein the first light blocking layer 414 and the second light blocking layer are each provided with an aperture corresponding to each microlens in the microlens array. For example, the metal layer 421 of the light detection array 42 at the top layer position may be multiplexed as the second light blocking layer to simplify the structure of the fingerprint detection device 40. The first light blocking layer 414 is provided with a first opening 415a corresponding to the first microlens 412a, a second opening 415b corresponding to the second microlens 412b, and a third opening 415c corresponding to the third microlens 412c. Similarly, fourth openings 422a corresponding to the first microlenses 412a, fifth openings 422b corresponding to the second microlenses 412b, and sixth openings 422c corresponding to the third microlenses 412c are provided in the second light blocking layer.

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

Compared with the scheme shown in fig. 5, the micro-prism array 410 converts the optical signal reflected by the finger and inclined relative to the display screen into the signal perpendicular to the display screen, and then the micro-lens and the micro-aperture diaphragm are used as the optical component to converge the perpendicular optical signal, so that the micro-lens in the micro-lens array has no shadow area, and the signal quantity and the fingerprint identification effect which can be received by the optical sensing unit array 424 are improved.

With continued reference to fig. 7, the at least one light blocking layer may include a plurality of light blocking layers, and openings in each light blocking layer corresponding to the same microlens sequentially decrease in aperture from top to bottom. For example, the aperture of the opening provided in the first light blocking layer 414 is larger than the aperture of the opening provided in the second light blocking layer. For example, the first opening 415a has a larger aperture than the fourth opening 422 a.

Of course, the apertures in each light blocking layer corresponding to the same microlens may be the same from top to bottom, which is not limited in the present application.

With continued reference to fig. 7, the at least one light blocking layer may include an underlying light blocking layer disposed at a back focal plane location of 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 bottom light blocking layer is provided with an opening corresponding to each optical sensing unit in the optical sensing unit array 424, where each optical sensing unit in the optical sensing unit array 424 receives an optical signal through the opening in the bottom light blocking layer corresponding to the same optical sensing unit. Optionally, the bottom light blocking layer is a metal wiring layer of the optical sensing unit array 424 (i.e., the metal layer 421 in the light detecting part 42) to simplify the structure of the fingerprint detection device 40. Of course, the metal layer 421 at any position in the light detecting portion 42 may be multiplexed as the underlying light blocking layer. For example, the metal layer 421 located at the top layer position, the middle position, or the bottom layer position in the light detection section 42 may be multiplexed as the bottom layer light blocking layer. For example, as shown in fig. 7, the metal layer 421 located at the top layer position in the light detection section 42 is multiplexed as the bottom light blocking layer. The material of the at least one light blocking layer may be an opaque material, whereby the open area of the at least one light blocking layer may be used to transmit light signals, and the non-open area of the at least one light blocking layer may prevent light signals that are not allowed to pass through, avoiding interference of the optical sensing unit array 424 by invalid light signals.

As an example, the underlying light blocking layer may be a second light blocking layer, that is, the second light blocking layer may be disposed at a rear focal plane position of the microlens array, and the second light blocking layer may be provided with an opening in an optical axis direction of each microlens of the microlens array. The second light blocking layer is provided with a fourth aperture 422a in the optical axis direction of the first microlens 412a, for example. Further, the second light blocking layer may also be provided inside the light detecting section 42, for example, formed using a metal layer in a back-end-of-line (BEOL) process. Namely, the metal wiring layer of the optical sensing unit array 424 is multiplexed to the bottom light blocking layer of the at least one light blocking layer, thereby reducing the thickness of the fingerprint detection device 40. Furthermore, the light guiding portion 41 may be integrated with the light detecting portion 42 on the same chip, so as to further reduce the thickness of the fingerprint detection device 40, and avoid occupying the space of other modules (such as a battery) in the electronic device.

With continued reference to fig. 7, the fingerprint detection device 40 may further include a filter 416. For example, the filter 416 may be an infrared cut filter (IR cut filter).

The light loss of the vertical optical signal passing through the filter is small compared to the oblique optical signal passing directly through the filter 416, and the filter 416 does not need to be customized, thereby reducing its manufacturing complexity.

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 unit 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 fingerprint detection 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-entering surface of the optical filter 416 may be provided with an optical inorganic coating or an organic blackening coating, so that the reflectivity of the light-entering surface of the optical filter is lower than a first threshold, for example, 1%, so that the optical sensing unit array 424 can be ensured to receive enough optical signals, and further fingerprint recognition effect is improved.

It should be appreciated that the optical filter 416 may be fabricated at any location along the optical path to the optical sensing element array 424 via the reflected light from the finger, as embodiments of the application are not limited in this regard.

As an example, the filter 416 may be disposed at any of the following positions: above the microprism array 410; between the microprism array 410 and the optical assembly; an interior of the optical assembly; and between the optical assembly and the array of optical sensing elements 424. For example, the optical filter 416 is disposed on the lower surface of the micro prism array 410, where the optical filter 416 is configured to receive the second optical signal (i.e., the optical signal perpendicular to the optical filter 416) converted by the micro prism array 410, so that the optical loss of the second optical signal in the optical filter 416 is effectively reduced, and the fingerprint recognition effect is further improved.

Taking the example that the optical filter 416 is fixed on the upper surface of the optical sensing unit array 424 by a fixing device, the optical filter 270 and the optical sensing pixel array 240 may be fixed by dispensing in a non-photosensitive area of the optical sensing pixel array 240, and a gap exists between the optical filter 270 and the photosensitive area of the optical sensing pixel array 240. Or the lower surface of the optical filter 270 is fixed on the upper surface of the optical sensing pixel array 240 by glue with a refractive index lower than a preset refractive index, for example, but not limited to, 1.3.

With continued reference to fig. 7, the fingerprint detection device 40 may further include a planar layer (planarization layer) 411 over the microlens array and an optical path layer 413 under the microlens array. The flat layer 411 and the light path layer 413 may be formed of a light-transmitting material, and a first light blocking layer 414 formed of a light-impermeable material may be disposed within the light path layer 413.

It should be appreciated that the microprism array 410 of the present application may be configured to receive only light at a particular angleAn incident reflected light signal from a finger (e.g., reflected light 34 shown in fig. 6). Taking the second microprism 410b as an example, by angle +.>The incident finger reflected light 34 passes through the two microprisms 410b to become a vertical light signal. The vertical optical signal firstly passes through the optical filter 416 to filter out the light of the non-target wave band, then is converged at the back focus under the action of the micro lens through the second micro lens 412b, namely is converged in the micro aperture 422b, and the optical signal passing through the micro aperture 422b is absorbed by the corresponding optical sensing unit 424b and is converted into corresponding electrical signal quantity according to a certain proportion to be output. Because the light intensity of the reflected light Iv from the fingerprint valley is larger than that of the reflected light Ir from the fingerprint ridge, the electric signal output by the acquisition unit corresponding to the valley is stronger and the image is brighter; the electric signal output by the corresponding collecting unit of the ridge is weaker, the image is darker, and finally the clear fingerprint image with a certain contrast is output. By no- >Incident reflected lightThe light signal still being oblique after passing through the second microprism 410b is converged in a region other than the focal point on the back focal plane by the second microprism 410b, and therefore cannot reach the second microprism 410b, and cannot be imaged.

The principle of converting a first optical signal reflected by a finger into a second optical signal in an embodiment of the present application will be described with reference to fig. 8.

Fig. 8 is a schematic diagram showing a process of changing the incident direction of light by the microprism of the embodiment of the present application. For convenience of description, it is assumed that an exit surface of each of the plurality of microprisms is parallel to the display screen, and an incident surface of each of the plurality of microprisms forms a second angle with the exit surface, so that the microprism array is used to convert the first optical signal into the second optical signal. It should also be understood that fig. 8 illustrates only the second microprisms 410b of the microprism array 410 shown in fig. 7, but the present application is not limited thereto.

Referring to fig. 8, the second microprism 410b includes an incident surface 501, an exit surface 502 and at least one supporting surface 500. When the incident light denoted by 51 (i.e., the reflected light 24 in fig. 5) reaches the 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 emission surface 502.

Assuming that the first optical signal forms a first included angle with a direction perpendicular to the display screen, the second included angle and the first included angle may satisfy the following relationship:

Assume thatAnd the refractive index of the material of the second microprism 410b is 1.55, and n is n since the incident light 51 is incident from air ₁ =1. The second included angle θ of the second microprisms 410b may be calculated to be 36 ° by the above formula. That is, the second microprisms 410b having the second angle of 36 ° may convert the first optical signal having the first angle of 30 ° into the second optical signal.

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 angle of the included angle formed by the entrance and exit faces of the microprisms in microprism array 410 can be determined by one skilled in the art based on 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 fingerprint detection device 40 can detect fingerprint information of a finger based on a large-angle oblique light signal, thereby improving fingerprint recognition effect.

It should be further noted that, the micro-prisms with specific angles in the embodiments of the present application may be manufactured by nano-imprinting or gray scale lithography, and the process is mature and will not be described herein.

A specific implementation of the microprism array 410 according to an embodiment of the application is described below.

In some embodiments of the present application, each of the microprisms in the microprism array 410 comprises at least one entrance face for receiving the first light signal and one exit face for emitting the second light signal, wherein each of the at least one entrance face is a plane inclined with respect to the display screen and the one exit face is a plane parallel with respect to the display screen.

As an example, an optical sensing unit is disposed under each incident surface of each micro prism of the micro prism array 410, and this scheme may be applied to the micro prism array 410 composed of micro prisms having a smaller size. For example, the micro prism array 410 may include a plurality of micro prism units distributed in an array, each of the plurality of micro prism units including a plurality of micro prisms distributed in a central symmetry, e.g., each of the plurality of micro prism units including 4 or 6 micro prisms. For another example, the microprism array 410 may comprise a plurality of microprisms distributed in an array.

As another example, a plurality of optical sensing units are disposed under each incident surface of each micro prism in the micro prism array 410. This may be applied to a micro prism array 410 composed of micro prisms having a larger size, for example, the micro prism array 410 includes a plurality of micro prisms arranged in a first direction, and a plurality of optical sensing units arranged in a second direction are disposed under each incident surface of each of the plurality of micro prisms, the first direction being perpendicular to the second direction. In other words, the micro prism array 410 may include the plurality of micro prisms distributed in an array, at least one row of the optical sensing units in the optical sensing unit array 424 is disposed under each of the plurality of micro prisms, or at least one column of the optical sensing units in the optical sensing unit array 424 is disposed under each of the plurality of micro prisms. Alternatively, the plurality of microprisms may include only one row of microprisms distributed in an array, with a column of microlenses disposed under each microprism. Alternatively, the plurality of microprisms may include only one column of microprisms distributed in an array, with a row of microlenses disposed under each microprism.

For ease of understanding, an example will be described below in which a row of microlenses is provided under each microprism.

Fig. 9 is a perspective view of the microprism array 410 shown in fig. 7. Fig. 10 is a schematic structural view of the fingerprint detection device 40 according to an embodiment of the present application in a top view. It should be understood that the number of microprisms and microlenses shown in the drawings is merely an example for convenience of description, but the present application is not limited thereto.

Referring to fig. 9, the micro prism array 410 may include only one row of micro prisms, and a row of micro lenses may be disposed under each micro prism. Alternatively, the first, second and third micro prisms 410a, 410b and 410c may have a bar-shaped structure.

Referring to fig. 10, the micro prism array 410 may include a first micro prism 410a and a second micro prism 410b, wherein a first optical sensing unit 424a and a fourth optical sensing unit 424d are disposed under the first micro prism 410a, and a second optical sensing unit 424b and a fifth optical sensing unit 424e may be disposed under the second micro prism 410 b. Further, a first micro lens 412a is disposed between the first micro prism 410a and the first optical sensing unit 424a, and a first micro aperture 422a is disposed below the first micro lens 412 a. Similarly, a fourth micro lens 412d is disposed between the first micro prism 410a and the fourth optical sensing unit 424d, and a fourth micro aperture 422d is disposed below the fourth micro lens 412 d. A second micro lens 412b is disposed between the second micro prism 410b and the second optical sensing unit 424b, and a second micro aperture 422b is disposed below the second micro lens 412 b. A fifth micro lens 412e is disposed between the second micro prism 410b and the fifth optical sensing unit 424e, and a fifth micro aperture 422e is disposed below the fifth micro lens 412 e. Alternatively, a row of microlenses is disposed under the first microprisms 410a, and a row of microlenses is disposed under the second microprisms 410 b.

The second optical signals converted by each micro-prism are converged through the micro-lens corresponding to the same micro-prism. Taking the second optical sensing unit 424b as an example, the second micro-prism 410b is configured to convert the first optical signal into a second optical signal, the second micro-lens 412b under the second micro-prism 410b transmits the received second optical signal to the second optical sensing unit 424b through the second micro-aperture 422b corresponding to the second micro-lens 412b, and the fifth micro-lens 412e under the second micro-prism 410b transmits the received second optical signal to the fifth optical sensing unit 424e through the fifth micro-aperture 422e corresponding to the fifth micro-lens 412 e.

Of course, fig. 9 and 10 are only examples of the present application and should not be construed as limiting the application.

In other alternative embodiments, for example, the array of microprisms 410 may comprise a plurality of rows of microprisms with at least one microlens disposed under each microprism; for another example, the array of microprisms 410 may include at least one column of microprisms with at least one microlens disposed under each microprism.

Fig. 11 is another schematic structural view of the fingerprint detection device 40 according to an embodiment of the present application in a top view. Fig. 12 and 13 are plan views of the microprism unit shown in fig. 11. It should be understood that the number of microprism units shown in the drawings is merely an example for convenience of description, but the present application is not limited thereto. For convenience of description, the drawings illustrate one microprism unit.

Referring to fig. 11, the fingerprint detection device 40 may include a plurality of microprism units 810 distributed in an array. The microprism unit 810 may include a plurality of microprisms. For example, each of the plurality of micro prism units 810 includes a plurality of micro prisms distributed in a center symmetry. For example, each micro-prism unit 810 of the plurality of micro-prism units 810 may include 4 micro-prisms. Alternatively, the distribution of the micro prisms included in each micro prism unit 810 of the plurality of micro prism units 810 may be polygonal, such as trilateral, quadrilateral, pentagonal, or hexagonal, etc., to simplify the arrangement of the optical sensing unit array 424. The projection 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 projection area of each micro lens of the micro lens array on the plane of the optical sensing unit array 424, so as to improve the utilization rate of the micro prism unit 810 and reduce the volume of the fingerprint detection device 40. Further, one microlens may be disposed under each of the microprisms in each of the microprism units 810. An opening in at least one light blocking layer is arranged below each microlens, and an optical sensing unit is arranged below each opening in the bottom light blocking layer in the at least one light blocking layer.

Wherein one micro prism unit 810 of the light guiding part 41 and the light detecting part 42 corresponding to the one micro prism unit 810 may be used to constitute one mother unit of the fingerprint detecting apparatus 40. That is, each of the mother units 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 a corresponding light detection section 42 therebelow, respectively.

It should be understood that the same reference numerals in fig. 11 as in fig. 7 may be used to designate the same components, and in order to avoid repetition, a detailed description is omitted herein.

Referring to fig. 12, each of the plurality of micro prism units 810 includes a plurality of micro prisms distributed in a center-symmetrical manner. For example, the micro prism unit 810 may include a first micro prism 810a, a second micro prism 810b, a third micro prism 810c, and a fourth micro prism 810d, and the micro prism unit 810 formed of the first micro prism 810a, the second micro prism 810b, the third micro prism 810c, and the fourth micro prism 810d may be formed as a truncated pyramid. For 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 a regular quadrangular endo-truncated pyramid, i.e., the top view of the micro prism unit 810 may be an area surrounded by ABCD as shown in fig. 8. Alternatively, the cross-sectional view shown in fig. 12 may be a cross-sectional view of fig. 11 in the OA direction.

If a coordinate system is established with the X-axis in the transverse direction and the Y-axis in the longitudinal direction, the directions of the first microprisms 810a, the second microprisms 810b, the third microprisms 810c, and the fourth microprisms 810d are different from each other with respect to the origin O, for example:

∠AOX＝135°，∠BOX＝45°，∠COX＝-45°，∠DOX＝-135°。

it can be seen that two adjacent microprisms in the microprism unit 810 are 90 degrees apart from the origin O. At this time, the microprism unit 810 may be used to receive light from four different directions and incident angles at the same timeIs reflected by the finger (light 831 and 832 in fig. 11 represent two directions thereof)) And further, dependence on finger placement angles during fingerprint verification is effectively reduced. Specifically, since the micro-prism units 810 can receive optical signals from multiple angles, and collect the optical signals from the multiple angles to multiple optical sensing units through multiple micro-lenses, the multiple optical sensing units under the micro-prism units 810 can be divided into multiple optical sensing unit groups, and the optical signals received by the optical sensing units under the micro-prism units 810 belonging to the same optical sensing unit group can be used to generate one fingerprint image, so that the multiple optical sensing pixel groups can be used to generate multiple fingerprint images, in this case, the multiple fingerprint images can be superimposed to obtain one fingerprint image with high resolution, and fingerprint recognition can be performed based on the fingerprint image with high resolution.

It can be seen that, by receiving the optical signals at a plurality of angles through each micro prism unit 810, even if the exposure time of the optical sensing unit array 424 is reduced, which results in lower resolution of each fingerprint image, a fingerprint image with higher resolution can be obtained by processing a plurality of fingerprint images with lower resolution. That is, the fingerprint detection device 40 not only can ensure fingerprint recognition effect, but also can reduce the exposure time of the optical sensing unit array 424 (i.e., image sensor).

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 optical 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 fig. 7-13 are only examples of the present application and should not be construed as limiting the present application.

As an example, 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.

As another example, embodiments of the present application are not limited to a particular shape in the microprism array 410. For example, each of the plurality of microprisms is a triangular prism or a trapezoidal prism, and for example, each of the plurality of microprisms is a rectangular prism, and an incident surface of each of the plurality of microprisms is an inclined surface of the rectangular prism. For example, each micro prism in the array of micro prisms 410 may be any one of the following: right angle triangular prism, isosceles triangular prism, right angle trapezoidal prism and isosceles trapezoidal prism.

As yet another example, embodiments of the present application are not limited to the specific structure of the optical assembly. For example, it may be the optical assembly 132 shown in fig. 1 or fig. 2. For example, the optical component can be a device formed by a micro lens array and a micro aperture diaphragm, and also can 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 another schematic cross-sectional structural view of the fingerprint detection device 40 according to an embodiment of the present application.

Referring to fig. 15, the optical component is a straight collimator 911, and the straight collimator 911 may be disposed onBetween the micro prism array 410 and the light detecting section 42, the collimator 911 may include a plurality of collimating holes 912 arranged in a certain manner, and as the only light-permeable area in the collimator 911, each optical sensing unit may correspond to one or more collimating holes 912. For example, each optical sensing unit may correspond to 3 collimating apertures 912. Incident angle isIs transmitted to the optical sensing array 424 through the straight collimator 911, and is converted into an electrical signal by the optical sensing array 424. The incident angle is not +.>Is blocked by the straight collimator 911 and thus does not reach the optical sensing array 424. In addition, the straight collimator 911 may also transmit the vertical light signal converted by each micro prism to an optical sensing unit under the same micro prism.

Compared with the scheme shown in fig. 6, the micro prism array 410 converts the optical signals reflected by the finger and inclined relative to the display screen into signals perpendicular to the display screen, and then the optical signals are screened by the straight-hole collimator 911, so that the manufacturing difficulty and cost of the collimator are effectively reduced.

In addition, since the angle 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 sensing unit array 424 needs to be prolonged. The plurality of straight holes are arranged above each photosensitive unit, so that the exposure time of the optical sensing unit array 424 can be effectively reduced, and the user experience is further improved.

It should be understood that fig. 15 is only an example of the present application and should not be construed as limiting the present application.

For example, the optical sensing unit array 424 and the straight collimator 911 may be integrally provided. I.e. the straight hole collimator 911 may be integrated within the chip of the light detecting section 92, for example forming the straight holes with a metal layer and a metal via layer in a subsequent process.

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. For example, the fingerprint detection device may further include a fingerprint image processing module, configured to quickly compare and identify the fingerprint image acquired by the optical sensing unit array 424 with a pre-stored fingerprint image. The fingerprint image processing module may be an Application Specific Integrated Circuit (ASIC) chip, a Digital Signal Processing (DSP) chip, or other chip or module with algorithm capability such as an Application Processor (AP).

The embodiment of the application also provides electronic equipment which can comprise a display screen and the fingerprint detection device, wherein the fingerprint detection device is arranged below the display screen so as to realize the optical fingerprint detection under the screen.

The electronic device may be any electronic device having a display screen.

The display screen may be a display screen in the above description, for example, an OLED display screen or other display screens, and the description of the display screen may refer to the description of the display screen in the above description, which is not repeated herein for brevity.

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. A fingerprint detection device adapted for use with an electronic device having a display screen for performing off-screen optical fingerprint detection, comprising:

the micro prism array is arranged below the display screen and comprises a plurality of micro prism units;

an optical assembly disposed below the micro-prism array, comprising a micro-lens array;

The optical signals received by the optical sensing unit array are used for detecting fingerprint information of the finger;

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

2. The fingerprint detection device according to claim 1 wherein each micro prism in said array of micro prisms comprises at least one entrance face for receiving said first light signal and one exit face for emitting said second light signal, wherein each of said at least one entrance face is a plane inclined with respect to said display screen and said one exit face is a plane parallel with respect to said display screen.

3. The fingerprint detection device according to claim 2 wherein said first light signal forms a first angle with a direction perpendicular to said display screen;

4. A fingerprint sensing device according to claim 3, wherein said first included angle is greater than or equal to 20 degrees.

5. The fingerprint detection device according to any one of claims 2-4 wherein an optical sensing unit is arranged below each entrance face of each micro prism of said array of micro prisms.

6. The fingerprint detection device according to claim 5 wherein said array of microprisms comprises a plurality of microprisms distributed in an array, each of said plurality of microprisms comprising a plurality of microprisms distributed in central symmetry.

7. The fingerprint detection device according to claim 6 wherein each of said plurality of microprism units comprises 4 microprisms.

8. The fingerprint detection device according to claim 5 wherein said array of microprisms comprises a plurality of microprisms distributed in an array.

9. The fingerprint detection device according to any one of claims 2-4 wherein a plurality of optical sensing units are arranged below each entrance face of each micro prism in the array of micro prisms.

10. The fingerprint detection device according to claim 9 wherein said array of microprisms comprises a plurality of microprisms arranged along a first direction, a plurality of optical sensing units arranged along a second direction being provided below each entrance face of each microprism of said plurality of microprisms, said first direction being perpendicular to said second direction.

11. The fingerprint detection device according to any one of claims 1-4 wherein each micro prism in said array of micro prisms is any one of:

12. The fingerprint detection device according to any one of claims 1-4 wherein said optical assembly comprises:

a micro lens array disposed below the micro prism array;

13. The fingerprint detection device according to claim 12, wherein the at least one light blocking layer comprises an underlying light blocking layer disposed at a back focal plane position of the microlens array.

14. The fingerprint detection device according to claim 13 wherein the underlying light blocking layer is a metal wiring layer of the array of optical sensing elements.

15. The fingerprint detection device according to claim 12 wherein the at least one light blocking layer comprises a plurality of light blocking layers, the openings in each light blocking layer corresponding to the same microlens decreasing in order from top to bottom.

16. The fingerprint detection device according to any one of claims 1-4 wherein said optical component is a straight hole collimator, each optical sensing element in said array of optical sensing elements corresponding to at least one collimating hole in said straight hole collimator;

the straight hole collimator is used for receiving the second optical signal converted by the micro prism array and transmitting the second optical signal to the optical sensing unit array through the collimating holes in the straight hole collimator.

17. The fingerprint detection device according to claim 16 wherein said array of optical sensing elements and said straight-hole collimator are integrally provided.

18. The fingerprint detection device according to any one of claims 1-4, wherein the fingerprint detection device further comprises:

a filter provided at least one of:

above the microprism array;

the microprism array and the optical assembly;

an interior of the optical assembly; and

the optical component and the optical sensing unit array.

19. A terminal device, comprising:

a display screen; and

a fingerprint sensing apparatus as claimed in claim 1 or 18.