CN210295120U - Fingerprint detection device and electronic equipment - Google Patents

Abstract

The embodiment of the application provides a fingerprint detection device and electronic equipment. The apparatus for fingerprint detection comprises an array of super-pixels, wherein the super-pixels comprise: a central photoactive pixel and a plurality of peripheral photoactive pixels, wherein the plurality of peripheral photoactive pixels surround the central photoactive pixel; a microlens covering the central photosensitive pixel and the plurality of peripheral photosensitive pixels; at least one light-blocking layer arranged between the micro-lens and the central photosensitive pixel and among the plurality of peripheral photosensitive pixels, wherein each light-blocking layer in the at least one light-blocking layer is provided with an opening corresponding to each photosensitive pixel in the central photosensitive pixel and the plurality of peripheral photosensitive pixels; and a second optical signal returned from the finger is transmitted to the peripheral photosensitive pixel through the micro lens and the opening corresponding to the peripheral photosensitive pixel.

Description

Fingerprint detection device and electronic equipment

Technical Field

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

Background

With the rapid development of the terminal industry, people pay more and more attention to the biometric identification technology, and the practicability of the more convenient under-screen biometric identification technology, such as the under-screen optical fingerprint identification technology, has become a requirement of the public.

Optical fingerprint identification technique under the screen sets up the optical fingerprint module in the display screen under, through gathering optical fingerprint image, realizes fingerprint identification. 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 easily lost, and the performance of fingerprint recognition is affected.

Therefore, how to improve the performance of fingerprint identification becomes a technical problem to be solved urgently.

SUMMERY OF THE UTILITY MODEL

The embodiment of the application provides a fingerprint detection device and electronic equipment, and the performance of fingerprint identification can be improved.

In a first aspect, there is provided a fingerprint detection device suitable for use under a display screen to perform optical fingerprint detection under the display screen, the device comprising an array of super pixels, wherein the super pixels comprise: a central photoactive pixel and a plurality of peripheral photoactive pixels, wherein the plurality of peripheral photoactive pixels surround the central photoactive pixel; a microlens covering the central photosensitive pixel and the plurality of peripheral photosensitive pixels; at least one light-blocking layer disposed between the microlens and the central photosensitive pixel and between the microlens and the plurality of peripheral photosensitive pixels, each light-blocking layer of the at least one light-blocking layer having an opening therein corresponding to each of the central photosensitive pixel and the plurality of peripheral photosensitive pixels; the central photosensitive pixel is configured to receive a first optical signal returned by a finger above the display screen, the first optical signal is transmitted to the central photosensitive pixel through the micro lens and the opening corresponding to the central photosensitive pixel, the peripheral photosensitive pixel is configured to receive a second optical signal returned by the finger, the second optical signal is transmitted to the peripheral photosensitive pixel through the micro lens and the opening corresponding to the peripheral photosensitive pixel, the first optical signal is an optical signal vertically incident relative to the array, the second optical signal is an optical signal inclined relative to the array and incident towards the center of the super pixel, and the first optical signal and the second optical signal are used for acquiring fingerprint information of the finger.

According to the technical scheme, the super pixels comprising the central photosensitive pixels and the peripheral photosensitive pixels are adopted, the central photosensitive pixels receive optical signals vertically incident relative to the array, the peripheral photosensitive pixels receive optical signals obliquely incident relative to the array, and the fingerprint identification performance can be improved.

In some possible implementations, the angle of incidence of the second optical signal with respect to the array is in a range of 25-45 degrees.

In some possible implementations, the angle of incidence of the second optical signal with respect to the array is in a range of 30-40 degrees.

In some possible implementations, the angle of incidence of the second optical signal with respect to the array is 35 degrees.

In some possible implementations, the incident directions of the second optical signals corresponding to the plurality of peripheral photosensitive pixels are symmetrically distributed around the center of the super pixel.

In some possible implementations, the plurality of peripheral photosensitive pixels are six peripheral photosensitive pixels, and the central photosensitive pixel and the six peripheral photosensitive pixels are hexagonal pixels.

The hexagonal pixels are structurally arranged, so that the symmetry is higher, the sampling efficiency is higher, the distances among adjacent pixels are equal, the angular resolution is better, and the aliasing effect is less.

In some possible implementations, the side lengths of the hexagonal shaped pixels range from 2um to 25 um.

In some possible implementations, the number of superpixels per row or column of the array is no less than 10.

In some possible implementations, the at least one light-blocking layer is a plurality of light-blocking layers, wherein a line of an opening of the plurality of light-blocking layers corresponding to the same peripheral photosensitive pixel is inclined with respect to the array to guide the second optical signal to the corresponding peripheral photosensitive pixel, and a line of an opening of the plurality of light-blocking layers corresponding to the central pixel is perpendicular with respect to the array to guide the first optical signal to the central pixel.

In some possible implementations, the apertures of the light blocking layers corresponding to the same pixel decrease sequentially from top to bottom.

In some possible implementations, the at least one light-blocking layer is a light-blocking layer, where an opening of the light-blocking layer corresponding to the peripheral photosensitive pixel is a slanted through hole to guide the second optical signal to the peripheral photosensitive pixel, and an opening of the light-blocking layer corresponding to the central pixel is a vertical through hole to guide the first optical signal to the central pixel.

In some possible implementations, the light blocking layer is a metal layer, and the opening is a through hole formed in the metal layer.

In some possible implementations, the opening is a cylindrical through hole, and the aperture of the opening is greater than 100 nm.

In some possible implementations, the super pixel further includes: and the transparent medium layer is used for connecting the micro lens, the at least one light blocking layer, the central photosensitive pixel and the plurality of peripheral photosensitive pixels and filling the opening.

In some possible implementations, the super pixel further includes: and the filter layer is arranged in a light path from the micro lens to the central photosensitive pixel and among the plurality of peripheral photosensitive pixels or above the micro lens and is used for filtering optical signals of non-target wave bands and transmitting the optical signals of the target wave bands.

In some possible implementations, the filter layer is a plated film formed on a surface of any one of the layers in the optical path.

In some possible implementations, the central photosensitive pixel and the plurality of peripheral photosensitive pixels are cmos devices, the cmos devices have a photosensitivity greater than a first predetermined threshold with respect to optical signals of a target wavelength band, and a quantum efficiency greater than a second predetermined threshold.

In some possible implementations, the exposure time of the device is determined by the brightness value of the center photosensitive pixel. In this way, the exposure time is the same as in the case of normal incidence, and the user experience can thus not be affected.

In some possible implementations, the apparatus further includes: and the processing unit is used for compensating the brightness values of the peripheral photosensitive pixels according to the brightness value of the central photosensitive pixel.

In a second aspect, an electronic device is provided, comprising a display screen and the first aspect or the fingerprint detection apparatus in any possible implementation manner of the first aspect, where the apparatus is disposed below the display screen to achieve optical fingerprint detection under the screen.

Drawings

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

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

Fig. 2A is another schematic structural diagram of an electronic device to which the present application may be applied.

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

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

FIG. 4 is a schematic diagram of a superpixel according to an embodiment of the present application.

Fig. 5 is a schematic structural diagram of a super pixel according to an embodiment of the present application.

Fig. 6 is a schematic diagram of an angular resolution of an apparatus for fingerprint detection according to an embodiment of the present application.

Fig. 7 is a schematic diagram of image processing of the fingerprint detection apparatus according to the embodiment of the present application.

Detailed Description

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

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

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

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

Fig. 1A to 2B are schematic diagrams illustrating an electronic device to which the embodiment of the present application is applicable. Fig. 1A and 2A are schematic orientation diagrams of the electronic device 10, and fig. 1B and 2B are schematic cross-sectional diagrams of the electronic device 10 shown in fig. 1A and 2A.

The electronic device 10 includes a display screen 120 and an optical fingerprint module 130. Wherein, the optical fingerprint module 130 is disposed in a local area below the display screen 120. The optical fingerprint module 130 includes an optical fingerprint sensor including a sensing array 133 having a plurality of optical sensing units 131 (which may also be referred to as photosensitive pixels, pixel units, etc.). The sensing array 133 is located in an area or a sensing area thereof, which is the fingerprint detection area 103 (also called a fingerprint collection area, a fingerprint identification area, etc.) of the optical fingerprint module 130. As shown in fig. 1, the fingerprint detection area 103 is located in a display area of the display screen 120. In an alternative embodiment, the optical fingerprint module 130 may be disposed at other positions, such as the side of the display screen 120 or the edge opaque region of the electronic device 10, and the optical path is designed to guide the optical signal from at least a part of the display region of the display screen 120 to the optical fingerprint module 130, so that the fingerprint detection region 103 is actually located in the display region of the display screen 120.

It should be understood that the area of the fingerprint detection area 103 may be different from the area of the sensing array 133 of the optical fingerprint module 130, for example, by designing an optical path such as lens imaging, a reflective folded optical path, or other optical path designs such as light converging or reflecting, the area of the fingerprint detection area 103 of the optical fingerprint module 130 may be larger than the area of the sensing array 133 of the optical fingerprint module 130. In other alternative implementations, if the light path is guided by, for example, light collimation, the fingerprint detection area 103 of the optical fingerprint module 130 may be designed to substantially coincide with the area of the sensing array of the optical fingerprint module 130.

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

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

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

For example, the light guide layer may specifically be a Collimator (collimater) layer manufactured on a semiconductor silicon wafer, and the collimater unit may specifically be a small hole, and in reflected light reflected from a finger, light perpendicularly incident to the collimater unit may pass through and be received by an optical sensing unit below the collimater unit, and light with an excessively large incident angle is attenuated by multiple reflections inside the collimater unit, so that each optical sensing unit can basically only receive reflected light reflected from a fingerprint pattern directly above the optical sensing unit, and the sensing array 133 can detect a fingerprint image of the finger.

In another implementation, the light guide layer or the light path guiding structure may also be an optical Lens (Lens) layer, which has one or more Lens units, such as a Lens group composed of one or more aspheric lenses, and is used to converge the reflected light reflected from the finger to the sensing array 133 of the light detection portion 134 therebelow, so that the sensing array 133 may perform imaging based on the reflected light, thereby obtaining the fingerprint image of the finger. Optionally, the optical lens layer may further form a pinhole in an optical path of the lens unit, and the pinhole may cooperate with the optical lens layer to enlarge a field of view of the optical fingerprint module 130, so as to improve a fingerprint imaging effect of the optical fingerprint module 130.

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

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

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

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

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

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

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

Optionally, with a plurality of optical fingerprint sensors of optical fingerprint module 130 are corresponding, there can be a plurality of light path guide structures in optical component 132, and every light path guide structure corresponds an optical fingerprint sensor respectively to laminate respectively and set up in its corresponding optical fingerprint sensor's top. Alternatively, the plurality of optical fingerprint sensors may share an integral optical path directing structure, i.e. the optical path directing structure has an area large enough to cover the sensing array of the plurality of optical fingerprint sensors. In addition, the optical assembly 132 may further include other optical elements, such as a Filter (Filter) or other optical film, which may be disposed between the optical path guiding structure and the optical fingerprint sensor or between the display screen 120 and the optical path guiding structure, and is mainly used for isolating the influence of external interference light on the optical fingerprint detection. The optical filter may be configured to filter ambient light that penetrates through a finger and enters the optical fingerprint sensors through the display screen 120, and similar to the optical path guiding structure, the optical filter may be respectively disposed for each optical fingerprint sensor to filter interference light, or may also cover the plurality of optical fingerprint sensors simultaneously with one large-area optical filter.

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

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

The embodiment of the application can be applied to detection of various fingers, and is particularly suitable for detection of dry fingers. By dry finger is meant a relatively dry finger or a relatively clean finger. The scheme of present fingerprint identification is not good enough to the fingerprint identification effect of dry finger, and the fingerprint identification's that this application embodiment provided scheme can promote the fingerprint identification performance to dry finger.

The fingerprint detection device of the embodiment of the application is suitable for optical fingerprint detection under the display screen below in order to realize the screen. Fig. 3 shows a schematic diagram of an apparatus 30 for fingerprint detection according to an embodiment of the present application. As shown in fig. 3, the device 30 includes an array of super pixels 300.

Optionally, the number of super pixels per row or column of the array is not less than 10.

It should be understood that the number of super pixels in the array may be set according to the size of the fingerprint detection area, the requirement of image resolution, and the like, and the specific number is not limited in the embodiment of the present application. The number of superpixels 300 shown in fig. 3 should not be construed as a limitation on the embodiments of the present application.

As shown in fig. 4 and 5, the super pixel 300 includes: a central photosensitive pixel 311 and a plurality of peripheral photosensitive pixels 312. The plurality of peripheral photoactive pixels 312 surround the central photoactive pixel 311.

Optionally, the plurality of peripheral photosensitive pixels 312 is six peripheral photosensitive pixels 312, that is, one super pixel 300 includes one central photosensitive pixel 311 and six peripheral photosensitive pixels 312. In this case, the center photosensitive pixel 311 and the six peripheral photosensitive pixels 312 are each a hexagonal pixel to achieve a close-packed arrangement of hexagonal pixels.

Optionally, the side length of the hexagonal shaped pixels ranges from 2um to 25 um.

The hexagonal pixels are structurally arranged, so that the symmetry is higher, the sampling efficiency is higher, the distances among adjacent pixels are equal, the angular resolution is better, and the aliasing effect is less.

As shown in fig. 6, for arc-shaped objects, the structural arrangement of hexagonal pixels can better image with better angular resolution.

Because the fingerprint texture is mostly the arc, consequently, the structure of hexagonal pixel is arranged and can be carried out the formation of image to the fingerprint better, and then improves fingerprint identification's performance.

It should be understood that the shapes of the central photosensitive pixel 311 and the peripheral photosensitive pixels 312 may also be other shapes, such as other polygons or circles, and the like, which is not limited by the embodiments of the present application.

As shown in FIG. 5, the illustrated superpixel 300 further includes: microlenses 320 and at least one light blocking layer 330.

The microlens 320 covers the central photosensitive pixel 311 and the plurality of peripheral photosensitive pixels 312. That is, all photosensitive pixels in a super pixel 300, i.e., the central photosensitive pixel 311 and all peripheral photosensitive pixels 312, correspond to one microlens 320.

The micro lens 320 may be various lenses having a condensing function for increasing a field of view and increasing an amount of light signals transmitted to the photosensitive pixels. The material of the microlens may be an organic material, such as a resin.

At least one light blocking layer 330 is disposed between the microlens 320 and the central photosensitive pixel 311 and the plurality of peripheral photosensitive pixels 312, and an opening 331 corresponding to the central photosensitive pixel 311 and each of the plurality of peripheral photosensitive pixels 312 is disposed in each light blocking layer 330 of the at least one light blocking layer 330.

A first optical signal 341 returned from a finger above the display screen is transmitted to the central photosensitive pixel 311 through the micro-lens 320 and the opening corresponding to the central photosensitive pixel 311, and a second optical signal 342 returned from the finger is transmitted to the peripheral photosensitive pixel 312 through the micro-lens 320 and the opening corresponding to the peripheral photosensitive pixel 312. The first optical signal 341 is an optical signal that is incident perpendicularly with respect to the array. The second light signal 342 is a light signal that is tilted with respect to the array and is incident toward the center of the superpixel 300.

Accordingly, the central photosensitive pixel 311 is configured to receive the first optical signal 341, and the peripheral photosensitive pixels 312 are configured to receive the second optical signal 342, so as to obtain fingerprint information of the finger.

The optical signal detected by the photosensitive pixel (the central photosensitive pixel 311 or the peripheral photosensitive pixel 312) can be used to form one pixel of the captured image.

The light-sensitive pixels may be photosensors for converting light signals to electrical signals. Alternatively, the photosensitive pixel may employ a Complementary Metal Oxide Semiconductor (CMOS) device, a Semiconductor device composed of a PN junction, and having a unidirectional conductive characteristic. Optionally, the light sensitivity of the light-sensitive pixel to blue light, green light, red light or infrared light is greater than a first predetermined threshold, and the quantum efficiency is greater than a second predetermined threshold. For example, the first predetermined threshold may be 0.5v/lux-sec and the second predetermined threshold may be 40%. That is, the photosensitive pixel has high light sensitivity and high quantum efficiency for blue light (wavelength of 460 ± 30nm), green light (wavelength of 540 ± 30nm), red light or infrared light (wavelength of ≧ 610nm) so as to detect the corresponding light.

It should be understood that the above parameters of the light-sensitive pixels may correspond to the light required for fingerprint detection, e.g. if the light required for fingerprint detection is only light of one wavelength band, the above parameters of the light-sensitive pixels need only meet the requirements of the light of that wavelength band.

In the embodiment, the second optical signal 342 received by the peripheral photosensitive pixels 312 is an oblique incident optical signal. Larger area of fingerprint peak-valley projection can be obtained by obliquely incident light signals, so that more continuous fingerprints can be obtained. For the condition of dry fingers, namely the contact area between the dry fingers and the display screen is very small, continuous fingerprints can be acquired through oblique light in optical signals transmitted by the fingers, and the identification effect of the dry fingers is further improved.

In the area where the finger is in contact with the display screen, a fingerprint (positive color fingerprint) can be acquired by the optical signal reflected by the contact interface, and in the area where the finger is not in contact with the display screen, a fingerprint (negative color fingerprint) can be acquired by the optical signal transmitted from the finger. For light signals in the vertical direction, the image of the positive and negative color transition zone is easy to be blurred. By adopting the super pixel structure in the embodiment of the application, the probability that only one pixel point in the center is blurred is large, and the rest pixels are not easy to be blurred, so that even if the center is blurred, the center can be compensated towards the middle by adopting an algorithm through the pixel points on the sides, and real-time calibration is realized.

Therefore, according to the technical scheme of the embodiment of the application, the super pixels comprising the central photosensitive pixels and the peripheral photosensitive pixels are adopted, the central photosensitive pixels receive optical signals vertically incident relative to the array, and the peripheral photosensitive pixels receive optical signals obliquely incident relative to the array, so that the fingerprint identification performance can be improved.

Optionally, in one embodiment of the present application, the angle of incidence of the second optical signal 342 with respect to the array may be in the range of 30-40 degrees.

Optionally, as an embodiment of the present application, the incident angle of the second optical signal 342 with respect to the array is 35 degrees. That is, the second optical signal 342 is tilted by 35 degrees.

It should be understood that the incident angle of the second optical signal 342 may also be other specific angles, and the specific angle may be set according to specific identification requirements or identification effects, for example, the incident angle may be in a larger range of 25-45 degrees, which is not limited by the embodiment of the present application.

Optionally, the incident directions of the second optical signals corresponding to the peripheral photosensitive pixels 312 are symmetrically distributed around the center of the super pixel. As shown in fig. 5, the second optical signals corresponding to the peripheral photosensitive pixels 312 are obliquely incident toward the center of the super pixel 300, and their incident directions are symmetrically distributed.

In the embodiments of the present application, the guiding of the optical signal is achieved by openings in the light-blocking layer. The light-blocking layer may be provided in one layer or in multiple layers.

Optionally, in an embodiment of the present application, the at least one light-blocking layer 330 is a multilayer light-blocking layer, wherein a line of an opening corresponding to the same peripheral photosensitive pixel in the multilayer light-blocking layer is inclined with respect to the array to guide the second optical signal to the corresponding peripheral photosensitive pixel, and a line of an opening corresponding to the central pixel in the multilayer light-blocking layer is perpendicular with respect to the array to guide the first optical signal to the central pixel.

For example, as shown in fig. 5, when a plurality of light-blocking layers are used, corresponding openings in the plurality of light-blocking layers are vertically disposed for the central photosensitive pixel 311, so that the central photosensitive pixel 311 can receive a vertically incident optical signal and block optical signals in other incident directions; for the peripheral photosensitive pixels 312, the corresponding openings in the light blocking layers are disposed obliquely, so that the peripheral photosensitive pixels 312 receive the obliquely incident optical signals and block the optical signals in other incident directions.

It should be appreciated that the angle at which the apertures corresponding to the peripheral photosensitive pixels 312 are obliquely disposed may be set according to the optical path of the second optical signal 342 to ensure that the second optical signal 342 is transmitted to the corresponding peripheral photosensitive pixels 312.

Optionally, in an embodiment of the present application, the apertures of the light-blocking layers 330 corresponding to the same pixel decrease sequentially from top to bottom.

For example, as shown in fig. 5, the aperture in the upper light-blocking layer is larger than the aperture in the lower light-blocking layer, so that more (a certain range of angles) of light signals can be directed to the corresponding photosensitive pixels.

Optionally, in an embodiment of the present application, the at least one light-blocking layer 330 is a light-blocking layer, wherein the opening of the light-blocking layer corresponding to the peripheral photosensitive pixel is an oblique through hole to guide the second optical signal to the peripheral photosensitive pixel, and the opening of the light-blocking layer corresponding to the central pixel is a vertical through hole to guide the first optical signal to the central pixel.

When one light blocking layer is adopted, the corresponding opening hole of the central photosensitive pixel 311 is a vertical through hole, so that the central photosensitive pixel 311 can receive a vertically incident optical signal and block optical signals in other incident directions; for the peripheral photosensitive pixels 312, the corresponding openings are oblique through holes, so that the peripheral photosensitive pixels 312 can receive the optical signals with oblique incidence, and block the optical signals with other incidence directions.

It should be understood that the inclination angle of the openings corresponding to the peripheral photosensitive pixels 312 may be set according to the optical path of the second optical signal 342 to ensure that the second optical signal 342 is transmitted to the corresponding peripheral photosensitive pixels 312.

Optionally, in an embodiment of the present application, the light-blocking layer 330 has a transmittance of less than 20% for light in a specific wavelength band (such as visible light or a wavelength band above 610nm) to prevent the corresponding light from passing through. For example, the light blocking layer 330 may be a metal layer, and accordingly, the opening 331 is a via hole formed in the metal layer.

Optionally, the opening 331 is a cylindrical through hole. In one embodiment of the present application, the aperture of the opening 331 is larger than 100nm, so as to transmit the required light for imaging. The aperture of the opening 331 is also smaller than a predetermined value to ensure that the light blocking layer 330 can block unwanted light. That is, the parameter setting of the opening 331 is such that the light signal required for imaging is maximally transmitted to the photosensitive pixel, and the undesired light is maximally blocked, as much as possible. For example, the parameters of the opening 331 may be set to maximize the transmission of vertically incident optical signals to the central photosensitive pixel 311, while maximizing the blocking of other optical signals, corresponding to the central photosensitive pixel 311; the parameters of the opening 331 may be set to maximize the transmission of light signals incident obliquely at a specific angle (e.g., 35 degrees) to the peripheral photosensitive pixels 312, while maximizing the blocking of other light signals, corresponding to the peripheral photosensitive pixels 312.

Optionally, in the embodiment of the present application, a transparent medium layer is further disposed between the microlens 320, the light blocking layer 330, and the photosensitive pixel.

The transparent medium layer is used to connect the microlens 320, the at least one light blocking layer 330, the central photosensitive pixel 311, and the plurality of peripheral photosensitive pixels 312, and fill the opening 331.

The transparent medium layer can be transparent to the optical signal of the target waveband (namely, the optical signal of the waveband required by fingerprint detection). For example, the transparent dielectric layer may be an oxide or a nitride.

Optionally, the transparent dielectric layer may include multiple layers to achieve the functions of protection, transition, buffering, and the like, respectively.

For example, a transition layer may be disposed between the inorganic layer and the organic layer to achieve a tight connection; a protective layer may be provided over the easily oxidizable layer to provide protection.

Optionally, in an embodiment of the present application, the super pixel 300 may further include: and a filter layer. The filtering layer is disposed in an optical path from the microlens 320 to the central photosensitive pixel 311 and the plurality of peripheral photosensitive pixels 312, or disposed above the microlens 320, and is configured to filter optical signals in a non-target wavelength band and transmit optical signals in a target wavelength band.

Optionally, the transmittance of the filter layer for light in a target wavelength band is greater than or equal to 80%, and the cut-off rate for light in a non-target wavelength band is greater than or equal to 80%.

Alternatively, the filter layer may be a separately formed filter layer. For example, the filter layer may be a filter layer formed by using blue crystal or blue glass as a carrier.

Optionally, the filter layer may be a plated film formed on a surface of any one of the optical paths. For example, the filter layer may be formed by plating a film on the surface of the photosensitive pixel, on the surface of any one of the transparent dielectric layers, or on the lower surface of the microlens.

Optionally, in an embodiment of the present application, the apparatus 30 may further include: a dielectric and a metal layer, which may include connection circuitry for the light-sensitive pixels.

The dielectric and metal layers may be disposed over the photosensitive pixels in a Front illumination (FSI) manner.

The dielectric and metal layers may also be disposed under the photosensitive pixels in a Back illumination (BSI) manner.

Optionally, in an embodiment of the present application, the exposure time of the device 30 is determined by the brightness value of the central photosensitive pixel 311.

Specifically, the optical path of an optical signal incident obliquely is longer than that of an optical signal incident perpendicularly, and the loss path increases, thereby affecting the amount of signals reaching the photosensitive pixels and increasing the exposure time. The exposure time is directly related to the user experience. Therefore, in the embodiment of the present application, the central photosensitive pixel is kept at normal incidence, and in a super pixel, the brightness value of the central photosensitive pixel can be saturated first, and the exposure time is determined by the brightness value of the central photosensitive pixel, that is, the exposure is stopped when the brightness value of the central photosensitive pixel is saturated. In this way, the exposure time is the same as in the case of normal incidence, and the user experience can thus not be affected.

In addition, the obliquely incident optical signal is mainly used for collecting data of fingerprint peaks and valleys, the size of a peak-valley difference value is mainly concerned, the larger the difference value is, the higher the contrast is, the easier the feature point is to be found, and further fingerprint identification is carried out; the absolute magnitude of the converted value after the pixel is exposed is not particularly important. Therefore, the exposure time can be used for acquiring required data and ensuring user experience.

Optionally, in an embodiment of the present application, the apparatus 30 may further include: and a processing unit.

The processing unit is configured to compensate the brightness values of the plurality of peripheral photosensitive pixels 312 according to the brightness value of the central photosensitive pixel 311.

In particular, the processing unit may process data collected by the photosensitive pixels to facilitate fingerprint recognition. As shown in fig. 7, the central photosensitive pixel 311 has a higher brightness value than the peripheral photosensitive pixels 312 due to the difference of the incident light signals. In this case, the processing unit may compensate the luminance values of the peripheral photosensitive pixels 312 according to the luminance value of the central photosensitive pixel 311 in one super pixel to obtain luminance saturation as a whole.

It should be appreciated that the manner of column-by-column exposure is used in fig. 7 for ease of viewing, and should not be construed as limiting the embodiments of the present application.

It should be understood that the device 30 may further include a support structure for supporting the device 30, and the like, which is not limited by the embodiments of the present application.

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 to realize optical fingerprint detection under the screen.

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

The display screen may be the display screen described above, such as an OLED display screen or other display screens, and for the description of the display screen, reference may be made to the description of the display screen in the above description, and for brevity, no further description is provided here.

It should be understood that the specific examples in the embodiments of the present application are for the purpose of promoting a better understanding of the embodiments of the present application and are not intended to limit the scope of the embodiments of the present application.

It is to be understood that the terminology used in the embodiments of the present application and the appended claims is for the purpose of describing particular embodiments only and is not intended to be limiting of the embodiments of the present application. For example, as used in the examples of this 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 components and steps of the examples have been described above generally in terms of their functionality in order to clearly illustrate the 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 implementation. 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 above-described apparatus embodiments are merely illustrative, and for example, the division of the units is only one logical division, and other divisions may be realized in practice, for example, a plurality of units or components may be combined or integrated into another system, or some features may be omitted, or not executed. In addition, the shown or discussed mutual coupling or direct coupling or communication connection may be an indirect coupling or communication connection through some interfaces, devices or units, and may also be an electric, mechanical or other form of connection.

The units described as separate parts may or may not be physically separate, and parts displayed 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 can be selected according to actual needs to achieve the purpose of the solution of the embodiments of the present application.

In addition, functional units in the embodiments of the present application may be integrated into one processing unit, or each unit may exist alone physically, or two or more units are integrated into one unit. The integrated unit can be realized in a form of hardware, and can also be realized in a form of a software functional unit.

The integrated unit, if implemented in the form of a software functional unit and sold or used as a stand-alone product, may be stored in a computer readable storage medium. Based on such understanding, the technical solution of the present application may be substantially or partially contributed by the prior art, or all or part of the technical solution may be embodied in a software product, which is stored in a storage medium and includes instructions for causing a computer device (which may be a personal computer, a server, or a network device) to execute 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), a magnetic disk or an optical disk, and other various media capable of storing program codes.

While the invention has been described with reference to specific embodiments, the scope of the invention is not limited thereto, and those skilled in the art can easily conceive various equivalent modifications or substitutions within the technical scope of the invention. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.

Claims (18)

1. An apparatus for fingerprint detection adapted for use below a display screen for performing optical fingerprint detection below the screen, the apparatus comprising an array of super-pixels, wherein the super-pixels comprise:

a central photoactive pixel and a plurality of peripheral photoactive pixels, wherein the plurality of peripheral photoactive pixels surround the central photoactive pixel;

a microlens covering the central photosensitive pixel and the plurality of peripheral photosensitive pixels;

at least one light-blocking layer disposed between the microlens and the central photosensitive pixel and between the microlens and the plurality of peripheral photosensitive pixels, each light-blocking layer of the at least one light-blocking layer having an opening therein corresponding to each of the central photosensitive pixel and the plurality of peripheral photosensitive pixels;

the central photosensitive pixel is configured to receive a first optical signal returned by a finger above the display screen, the first optical signal is transmitted to the central photosensitive pixel through the micro lens and the opening corresponding to the central photosensitive pixel, the peripheral photosensitive pixel is configured to receive a second optical signal returned by the finger, the second optical signal is transmitted to the peripheral photosensitive pixel through the micro lens and the opening corresponding to the peripheral photosensitive pixel, the first optical signal is an optical signal vertically incident relative to the array, the second optical signal is an optical signal inclined relative to the array and incident towards the center of the super pixel, and the first optical signal and the second optical signal are used for acquiring fingerprint information of the finger.

2. The apparatus of claim 1, wherein an angle of incidence of the second optical signal with respect to the array is in a range of 30-40 degrees.

3. The apparatus of claim 2, wherein the second optical signal has an angle of incidence of 35 degrees with respect to the array.

4. The apparatus of claim 1, wherein the incident directions of the second optical signals corresponding to the peripheral photosensitive pixels are symmetrically distributed about the center of the super pixel.

5. The device of claim 1, wherein the plurality of peripheral photoactive pixels is six peripheral photoactive pixels, and wherein the center photoactive pixel and the six peripheral photoactive pixels are hexagonal-shaped pixels.

6. The apparatus of claim 5, wherein the side length of the hexagonal-shaped pixels is in a range of 2um to 25 um.

7. The apparatus of claim 1, wherein the number of superpixels per row or column of the array is no less than 10.

8. The apparatus according to claim 1, wherein the at least one light-blocking layer is a plurality of light-blocking layers, wherein a line of an opening of the plurality of light-blocking layers corresponding to a same peripheral photosensitive pixel is tilted with respect to the array to direct the second light signal to a corresponding peripheral photosensitive pixel, and a line of an opening of the plurality of light-blocking layers corresponding to the central photosensitive pixel is perpendicular with respect to the array to direct the first light signal to the central photosensitive pixel.

9. The apparatus of claim 8, wherein the apertures of the light-blocking layers corresponding to the same pixel decrease in aperture from top to bottom.

10. The apparatus according to claim 1, wherein the at least one light-blocking layer is a light-blocking layer, wherein the openings in the light-blocking layer corresponding to the peripheral photosensitive pixels are oblique through holes for guiding the second optical signals to the peripheral photosensitive pixels, and the openings in the light-blocking layer corresponding to the central photosensitive pixels are vertical through holes for guiding the first optical signals to the central photosensitive pixels.

11. The apparatus of claim 1, wherein the light blocking layer is a metal layer, and the opening is a via formed in the metal layer.

12. The device of claim 11, wherein the opening is a cylindrical via having a pore size greater than 100 nm.

13. The apparatus of claim 1, wherein the super pixel further comprises:

and the transparent medium layer is used for connecting the micro lens, the at least one light blocking layer, the central photosensitive pixel and the plurality of peripheral photosensitive pixels and filling the opening.

14. The apparatus of claim 1, wherein the super pixel further comprises:

and the filter layer is arranged in a light path from the micro lens to the central photosensitive pixel and among the plurality of peripheral photosensitive pixels or above the micro lens and is used for filtering optical signals of non-target wave bands and transmitting the optical signals of the target wave bands.

15. The apparatus of claim 14, wherein the filter layer is a coating formed on a surface of any one of the layers in the optical path.

16. The apparatus of claim 1, wherein the central photoactive pixel and the plurality of peripheral photoactive pixels are each a CMOS device having a photosensitivity greater than a first predetermined threshold for optical signals in a target wavelength band and a quantum efficiency greater than a second predetermined threshold.

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

and the processing unit is used for compensating the brightness values of the peripheral photosensitive pixels according to the brightness value of the central photosensitive pixel.

18. An electronic device comprising a display screen and an apparatus for fingerprint detection according to any one of claims 1 to 17, said apparatus being arranged below said display screen to enable an off-screen optical fingerprint detection.

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