CN111801684A - Fingerprint detection devices and electronic equipment - Google Patents

Abstract

The embodiment of the application provides a fingerprint detection device and electronic equipment, and the performance of fingerprint identification can be improved. This fingerprint detection's device is applicable to the below of display screen in order to realize optical fingerprint detection under the screen, the display screen includes fingerprint detection area, fingerprint detection area includes first region and second area, the second area encircles first region, the device includes: an optical path guiding structure for guiding a first return light signal formed by a finger above the display screen to an optical sensor, wherein the first return light signal is a light signal in which pixels in the first area do not emit light, and light emitted by pixels in the second area is transmitted into the finger, and then transmitted out of the finger and through the display screen; an optical sensor disposed below the optical path guide structure for receiving the first return light signal passing through the optical path guide structure, the first return light signal being used to acquire a fingerprint image of the finger.

Description

Fingerprint detection devices and electronic equipment

technical field

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

Background technique

With the rapid development of the terminal industry, more and more attention has been paid to biometric identification technology, and the practical application of more convenient under-screen biometric identification technology, such as under-screen optical fingerprint identification technology, has become a popular demand.

The current optical screen fingerprint technology is basically applied to the mobile phone screen of self-luminous organic light-emitting diode (Organic Light-Emitting Diode, OLED). Finger reflection, through the phone screen and special optical lens, is received by the sensor under the screen to realize fingerprint image collection and fingerprint recognition. This method has some shortcomings, for example, it is difficult to identify wet fingers and cannot be used for anti-counterfeiting of 2D fake fingers.

SUMMARY OF THE INVENTION

The embodiments of the present application provide an apparatus and electronic device for fingerprint detection, which can improve the performance of fingerprint recognition.

In a first aspect, a fingerprint detection device is provided, which is suitable for use under a display screen to realize off-screen optical fingerprint detection, the display screen includes a fingerprint detection area, and the fingerprint detection area includes a first area and a second area, The second area surrounds the first area, and the fingerprint detection device includes: an optical path guiding structure for guiding a first return light signal formed by a finger above the display screen to an optical sensor, wherein the The first return light signal is the light signal that the pixels in the first area do not emit light, the light emitted by the pixels in the second area transmits into the finger, and then transmits from the finger and passes through the display screen; The optical sensor is arranged below the optical path guiding structure, and is used for receiving the first return light signal passing through the light path guiding structure, and the first return light signal is used for acquiring the fingerprint image of the finger.

In the technical solution of the embodiment of the present application, the pixels in the first area of the fingerprint detection area do not emit light, and the light emitted by the pixels in the second area transmits into the finger, and then transmits from the finger and passes through the display screen , the transmitted light through the finger is detected to obtain the fingerprint pattern of the finger, the imaging quality is higher, the recognition ability of the wet finger can be improved, and the 2D fake finger can be anti-counterfeited. Therefore, the technical solution can improve the performance of fingerprint recognition.

In a possible implementation manner, the size of the first area is not smaller than the diameter of the field of view of the fingerprint sensor.

In a possible implementation manner, the vertical projection area of the first region coincides with the vertical projection area of the field of view of the fingerprint sensor, or the vertical projection area of the first region covers the field of view of the fingerprint sensor. Field vertical projection area.

In a possible implementation manner, the size L of the first region satisfies:

D≤L≤D+2×d×tanα

Wherein, the D is the diameter of the field of view of the optical sensor, the d is the distance between the pixels in the second area and the upper surface of the display screen, and the α represents the light emission angle of the pixels.

In a possible implementation manner, the shape of the first area is a circle or a square, and the boundary shape of the second area is a circle or a square.

In a possible implementation manner, the combined shape of the first region and the second region is a concentric circle.

In a possible implementation manner, the light emitted by the pixels in the second area is red light or yellow light.

In a possible implementation manner, the device further includes: an optical filter located above the optical fingerprint sensor, the optical filter is used to filter out other optical signals other than the first returned optical signal.

In a possible implementation manner, the wavelength range of the first returned optical signal is 600-660 nm, and the optical filter is used to filter out light whose wavelength is not equal to 600-660 nm.

In a possible implementation manner, the optical path guiding structure includes an optical lens, and the optical lens is disposed above the optical fingerprint sensor, and is used for converging the first return light signal passing through the display screen to a The sensing array of the optical fingerprint sensor.

In a possible implementation manner, the optical path guiding structure includes a microlens array with a plurality of microlenses and a light blocking layer with a plurality of microholes, the microlens array is used to The first returned light signal is respectively focused to the corresponding micro-holes of the light blocking layer through the plurality of micro-lenses, and transmitted to the corresponding optical sensing units in the sensing array of the optical fingerprint sensor through the micro-holes.

In a possible implementation manner, the light intensity of the first returned light signal received by the optical sensor is used to determine whether the finger is a real finger.

In a possible implementation manner, if the light intensity of the first returned light signal received by the optical sensor is greater than or equal to a preset value, the finger is a real finger; If the light intensity of the first returned light signal is less than the preset value, the finger is a fake finger.

The technical solutions provided by the embodiments of the present application can not only identify a wet finger, but also determine whether the finger is a real finger according to the received light intensity of the first optical signal.

In a second aspect, an electronic device is provided, including the device for fingerprint detection in the first aspect or any possible implementation manner of the first aspect, where the device is disposed below the display screen to implement an off-screen optical fingerprint detection.

In a possible implementation manner, the electronic device further includes: a processor, configured to determine whether the finger is a real finger according to the light intensity of the first returned light signal received by the optical sensor.

In a possible implementation manner, the processor is specifically configured to: determine that the finger is a real finger if the light intensity of the first returned light signal received by the optical sensor is greater than or equal to a preset value; If the light intensity of the first returned light signal received by the optical sensor is less than the preset value, it is determined that the finger is a fake finger.

Description of 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 is a schematic diagram of a model of fingerprint imaging according to reflected light after a finger is illuminated by a light source.

Figure 6 is a reflected light fingerprint image of a normal finger.

Figure 7 is a reflected light fingerprint image of a wet finger.

FIG. 8 is a schematic diagram of a model of fingerprint imaging based on transmitted light after a finger is illuminated by a light source.

Figure 9 is a transmitted light fingerprint image of a normal finger.

Figure 10 is a transmitted light fingerprint image of a wet finger.

FIG. 11 is a schematic side view of an electronic device according to an embodiment of the present application when fingerprint detection is performed.

FIG. 12 is a schematic front view of an electronic device according to an embodiment of the present application.

FIG. 13 is a schematic cross-sectional view of the dimensions of different areas in the fingerprint detection area.

14( a ) to 14 ( d ) are schematic diagrams showing the shape combination of the first area and the second area in the fingerprint detection area.

FIG. 15 is a schematic diagram of fingerprint recognition performed by a 2D fake finger on an electronic device according to an embodiment of the present application.

Detailed ways

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

The technical solutions of the embodiments of the present application can be applied to various electronic devices. Examples include portable or mobile computing devices such as smartphones, laptops, tablets, gaming devices, and other electronic devices such as electronic databases, automobiles, and bank Automated Teller Machines (ATMs). However, the embodiments of the present application do not limit this.

The technical solutions of the embodiments of the present application can be used for biometric identification technology. Among them, biometric identification technologies include but are not limited to identification technologies such as fingerprint identification, palmprint identification, iris identification, face identification, and living body identification. For convenience of description, the following description takes the fingerprint identification technology as an example.

The technical solutions of the embodiments of the present application can be used for the off-screen fingerprint recognition technology and the on-screen fingerprint recognition technology.

The under-screen fingerprint recognition technology refers to installing the fingerprint recognition module under the display screen, so as to realize the fingerprint recognition operation in the display area of the display screen, and it is not necessary to set a fingerprint collection area on the front of the electronic device except the display area. 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 on objects (such as fingers) in contact with or approaching the top surface of the display assembly. The fingerprint recognition module located below the display assembly collects and detects this returned light to realize off-screen fingerprint recognition. Wherein, the design of the fingerprint identification module can be such that desired optical imaging can be realized by properly configuring the optical element for collecting and detecting the returned light, so as to detect the fingerprint information of the finger.

Correspondingly, the in-display fingerprint recognition technology refers to installing the fingerprint recognition module or part of the fingerprint recognition module inside the display screen, so as to realize the fingerprint recognition operation in the display area of the display screen, without the need for electronic The fingerprint collection area is set on the front of the device except the display area.

1 to 4 are schematic diagrams of electronic devices to which the embodiments of the present application may be applied. 1 and 3 are schematic diagrams of orientation of the electronic device 10 , and FIGS. 2 and 4 are schematic cross-sectional views of the electronic device 10 shown in FIGS. 1 and 3 , respectively.

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

The display screen 120 may be a self-luminous display screen, which uses display units having self-luminescence as display pixels. For example, the display screen 120 may be an organic light-emitting diode (Organic Light-Emitting Diode, OLED) display screen or a micro light-emitting diode (Micro-LED) display screen. In other alternative embodiments, the display screen 120 may also be a liquid crystal display (Liquid Crystal Display, LCD) or other passive light-emitting display screen, which is not limited in this embodiment of the present application. Further, the display screen 120 may also be specifically a touch display screen, which can not only display a screen, but also detect a user's touch or pressing operation, thereby providing a human-computer interaction interface for the user. For example, in one embodiment, the electronic device 10 may include a touch sensor, and the touch sensor may specifically be a touch panel (Touch Panel, TP), which may be disposed on the surface of the display screen 120, or may be partially integrated or The whole is integrated into the display screen 120 to form the touch display screen.

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

Wherein, the optical fingerprint module 130 is arranged in a partial area below the display screen 120 .

Please continue to refer to FIG. 1 , the fingerprint detection area 103 may be located in the display area of the display screen 120 . In an alternative embodiment, the optical fingerprint module 130 can also be arranged in other positions, such as the side of the display screen 120 or the non-transparent area of the edge of the electronic device 10, and the optical path design is used to The optical signal from at least part of the display area of the display screen 120 is guided to the optical fingerprint module 130 , 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 to realize fingerprint input. Since fingerprint detection can be implemented in the screen, the electronic device 10 using the above structure does not need to reserve a space on the front of the electronic device 10 to set a fingerprint button (such as the Home button), so that a full-screen solution can be adopted, that is, the display area of the display screen 120 It can extend to substantially the entire front of the electronic device 10 .

Please continue to refer to FIG. 2 , the optical fingerprint module 130 may include a light detection part 134 and an optical component 132 . The light detection part 134 includes the sensing array 133 (also referred to as an optical fingerprint sensor), a reading circuit and other auxiliary circuits electrically connected to the sensing array 133, which can be fabricated on a chip by a semiconductor process. (Die), such as an optical imaging chip or an optical fingerprint sensor. The sensing array 133 is specifically a photo detector array, which includes a plurality of photo detectors distributed in an array, and the photo detectors can be used as the above-mentioned optical sensing units. The optical component 132 may be disposed above the sensing array 133 of the light detection part 134, and may specifically include a filter layer (Filter), a light guide layer or a light path guide structure, and other optical elements, the filter layer. It can be used to filter out ambient light penetrating the finger, and the light guide layer or the light path guiding structure is mainly used to guide the reflected light reflected from the finger surface to the sensing array 133 for optical detection.

In some embodiments of the present application, the optical assembly 132 and the light detection part 134 may be packaged in the same optical fingerprint component. For example, the optical component 132 and the optical detection part 134 can be packaged in the same optical fingerprint chip, or the optical component 132 can be arranged outside the chip where the optical detection part 134 is located, for example, the optical component 132 It is attached above the chip, or some components of the optical component 132 are integrated into the chip.

In some embodiments of the present application, the area or 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 . Wherein, the fingerprint collection area 103 of the optical fingerprint module 130 may or may not be equal to the area or light sensing range of the area where the sensing array 133 of the optical fingerprint module 130 is located, which is not specifically limited in this embodiment of the present application .

For example, the optical path is guided by light collimation, and the fingerprint detection area 103 of the optical fingerprint module 130 can be designed to be substantially the same as the area of the sensing array of the optical fingerprint module 130 .

For another example, the area of the fingerprint detection area 103 of the optical fingerprint module 130 can be made larger than that of the optical fingerprint module by, for example, optical path design of lens imaging, reflective folding optical path design, or other optical path designs such as light convergence or reflection. 130 of the area of the sensing array 133 .

The following is an exemplary description of the optical path guiding structure that the optical assembly 132 may include.

Taking the optical path guiding structure using an optical collimator with a high aspect ratio through-hole array as an example, the optical collimator may be specifically a collimator layer fabricated on a semiconductor silicon wafer, which has A plurality of collimation units or micro-holes, the collimation unit can be specifically a small hole, from the reflected light from the finger, the light perpendicularly incident to the collimation unit can pass through and be received by the sensor chip below it , and the light with an excessively large incident angle is attenuated after multiple reflections inside the collimating unit, so each sensor chip can basically only receive the reflected light from the fingerprint pattern directly above it, which can effectively improve the image resolution. rate, thereby improving the fingerprint recognition effect.

Taking the optical path design of the optical path guide structure using an optical lens as an example, the optical path guide structure can be an optical lens (Lens) layer, which has one or more lens units, such as a lens group composed of one or more aspherical lenses , which is used to condense the reflected light from the finger to the sensing array 133 of the light detection part 134 below it, so that the sensing array 133 can perform imaging based on the reflected light, thereby obtaining the fingerprint image of the finger . Further, the optical lens layer may also be formed with pinholes or micro-aperture diaphragms 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 A light-shielding sheet may be formed with light-transmitting micro-holes in the optical axis or optical center region of the lens unit, and the light-transmitting micro-holes may be used as the above-mentioned pinholes or micro-aperture diaphragms. The pinhole or micro-aperture diaphragm can cooperate with the optical lens layer and/or other optical film layers above the optical lens layer to expand the field of view of the optical fingerprint module 130 to improve the optical fingerprint module 130 fingerprint imaging effect.

Taking the optical path design of the optical path guiding structure using a micro-lens (Micro-Lens) layer as an example, the optical path guiding structure may include a microlens array formed by a plurality of microlenses, which may be formed by a semiconductor growth process or other processes Above the sensing array 133 of the light detection part 134 , and each microlens may correspond to one of the sensing units of the sensing array 133 respectively. In addition, other optical film layers, such as a dielectric layer or a passivation layer, may also be formed between the microlens layer and the sensing unit. More specifically, a light-blocking layer (or called a light-shielding layer, a light-blocking layer, etc.) with micro-holes (or called openings) may be further included between the micro-lens layer and the sensing unit, wherein the micro- The hole is formed between its corresponding microlens and the sensing unit, and the light blocking layer can block the optical interference between adjacent microlenses and the sensing unit, and make the light corresponding to the sensing unit converge through the microlens into the inside of the micro-hole and transmitted to the sensing unit via the micro-hole for optical fingerprint imaging.

It should be understood that the above several implementation solutions for the optical path guiding structure can 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, its specific stack structure or optical path 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 films, which may be disposed between the optical path guiding structure and the optical fingerprint sensor or disposed in all The space between the display screen 120 and the optical path guiding structure is mainly used to isolate the influence of external interference light on the optical fingerprint detection. The filter layer can be used to filter out ambient light that penetrates the finger and enters the optical fingerprint sensor through the display screen 120. Similar to the optical path guiding structure, the filter layer can be used for each The optical fingerprint sensors are separately arranged to filter out interfering light, or a large-area filter layer can be used to cover the multiple optical fingerprint sensors at the same time.

The fingerprint identification module 130 may be used to collect fingerprint information (such as fingerprint image information) of the user.

Taking the display screen 120 as an example of a display screen having a self-luminous display unit, such as an organic light-emitting diode (Organic Light-Emitting Diode, OLED) display screen or a micro-light-emitting diode (Micro-LED) display screen. The optical fingerprint module 130 can use the display unit (ie, the 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 on the fingerprint detection area 103, the display screen 120 emits a beam of light 111 to the target finger 140 above the fingerprint detection area 103, and the light 111 is reflected on the surface of the finger 140 to form reflected light or passes through all the The finger 140 is internally scattered to form scattered light (transmitted light). In the related patent application, for the convenience of description, the above-mentioned reflected light and scattered light are collectively referred to as reflected light. Since the ridges 141 and valleys 142 of the fingerprint have different reflection capabilities for light, the reflected light 151 from the fingerprint ridges and the reflected light 152 from the fingerprint valleys have different light intensities, and the reflected light passes through the optical component 132 Then, it is received by the sensing array 133 in the optical fingerprint module 130 and converted into a corresponding electrical signal, that is, a fingerprint detection signal; based on the fingerprint detection signal, fingerprint image data can be obtained, and fingerprint matching verification can be further performed, thereby The optical fingerprint recognition function is implemented in the electronic device 10 .

In other alternative solutions, the optical fingerprint module 130 may also use a built-in 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 can be applied not only to self-luminous display screens such as OLED display screens, but also to non-self-luminous display screens, such as liquid crystal display screens or other passive light-emitting display screens.

Taking an application in a liquid crystal display with a backlight module and a liquid crystal panel as an example, in order to support fingerprint detection under the LCD screen, the optical fingerprint system of the electronic device 10 may further include an excitation light source for optical fingerprint detection, the excitation The light source can be specifically an infrared light source or a light source of non-visible light with a specific wavelength, which can be arranged under the backlight module of the liquid crystal display or in the edge area under the protective cover of the electronic device 10, and the optical fingerprint module. 130 can be arranged under the edge area of the liquid crystal panel or the protective cover and guided by the optical path so that the fingerprint detection light can reach the optical fingerprint module 130; or, the optical fingerprint module 130 can also be arranged in the backlight module. below, and the backlight module allows 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 film layers such as diffusion sheets, brightening sheets, and reflective sheets. . When the optical fingerprint module 130 uses a built-in light source or an external light source to provide an optical signal for fingerprint detection, the detection principle is consistent with the above description.

In terms of 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, which is located above the display screen 120 and covers the front surface of the electronic device 10 . Therefore, in the embodiments of the present application, the so-called finger pressing on the display screen 120 actually refers to 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. At this time, the fingerprint detection area 103 of the optical fingerprint module 130 has a small area and a fixed position, so the user needs to press the finger when inputting the fingerprint. Otherwise, the optical fingerprint module 130 may not be able to collect the fingerprint image, resulting in poor user experience. In other alternative embodiments, the optical fingerprint module 130 may specifically include multiple optical fingerprint sensors. The multiple optical fingerprint sensors can be arranged side by side under the display screen 120 by splicing, and the sensing areas of the multiple optical fingerprint sensors together constitute the fingerprint detection area 103 of the optical fingerprint module 130 . Therefore, 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 area where the finger is usually pressed, so as to realize the blind-pressing fingerprint input operation. Further, when the number of the optical fingerprint sensors is sufficient, the fingerprint detection area 103 can also be extended to half the display area or even the entire display area, so as to realize fingerprint detection on a half screen or a full screen.

Referring to FIGS. 3 and 4 , the optical fingerprint module 130 in the electronic device 10 may include multiple optical fingerprint sensors, and the multiple optical fingerprint sensors may be arranged side by side on the display screen 120 by, for example, splicing or the like. Below, and the sensing areas of the plurality of optical fingerprint sensors together constitute the fingerprint detection area 103 of the optical fingerprint device 130 .

Further, the optical assembly 132 may include a plurality of optical path guiding structures, each of which corresponds to an optical fingerprint sensor (ie, the sensing array 133 ), and is respectively attached and disposed above its corresponding optical fingerprint sensor. Alternatively, the plurality of optical fingerprint sensors may also share an integral optical path guiding structure, that is, the optical path guiding structure has an area large enough to cover the sensing arrays of the plurality of optical fingerprint sensors.

Taking the optical assembly 132 using an optical collimator with a high aspect ratio through-hole array as an example, when the optical fingerprint module 130 includes a plurality of optical fingerprint sensors, the optical sensing array of each optical fingerprint sensor can be used as an example. One of the optical sensing units is configured with one or more collimation units, and is attached and arranged above its corresponding optical sensing unit. Of course, the multiple optical sensing units may also share one collimating unit, that is, the one collimating unit has an aperture large enough to cover the multiple optical sensing units. Since one collimation unit may correspond to multiple optical sensing units or one optical sensing unit may correspond to multiple collimation units, the correspondence between the space period of the display screen 120 and the space period of the optical fingerprint sensor is destroyed. The spatial structure of the light-emitting display array is similar to that of the optical sensing array of the optical fingerprint sensor, which can also effectively prevent the optical fingerprint module 130 from using the optical signal passing through the display screen 120 to perform fingerprint imaging to generate Moiré fringes, effectively improving the optical fingerprint model. Fingerprint recognition effect of group 130.

Taking the optical assembly 132 using an optical lens as an example, when the optical fingerprint module 130 includes multiple sensor chips, each sensor chip can be configured with an optical lens to perform fingerprint imaging, or multiple sensor chips can be configured with an optical lens for fingerprint imaging. Achieve light convergence and fingerprint imaging. Even when a sensor chip has two sensing arrays (Dual Array) or multiple sensing arrays (Multi-Array), this sensor chip can also be configured with two or more optical lenses to cooperate with the two sensing arrays or Multiple sensing arrays perform optical imaging to reduce imaging distance and enhance imaging.

It should be understood that the accompanying drawings 1 to 4 are only examples of the present application, and should not be construed as limiting the present application.

For example, the present application does not specifically limit the number, size and arrangement of fingerprint sensors, which can be adjusted according to actual needs. For example, the optical fingerprint module 130 may include a plurality of fingerprint sensors distributed in a square or a circle.

At present, the fingerprint recognition technology under the screen mainly uses the principle of reflected light imaging for fingerprint recognition. As shown in FIG. 5 , after the light signal emitted by the pixels in the self-luminous display screen 120 irradiates the finger, a part of the light signal is transmitted and the other part of the light signal is reflected. Since the refractive index of the finger tissue is 1.43, the refractive index of the optical signal at the fingerprint ridge is similar to the refractive index of the display screen 120 (about 1.5), the intensity of the transmitted optical signal at the ridge is higher, and the intensity of the reflected optical signal is higher. weaker. Since the fingerprint valley is filled with air, the refractive index of the air is 1, and the difference with the refractive index of the display screen 120 is large, so the intensity of the transmitted light signal at the fingerprint valley is weak, and the intensity of the reflected light signal is high. . The contrast ratio of the intensity of the light signal reflected back at the fingerprint ridges and the fingerprint valleys is about 1:40. Therefore, according to the intensity difference of the reflected light signal at the fingerprint ridge and the fingerprint valley, a fingerprint image of the finger can be obtained, and further fingerprint identification can be performed. As shown in FIG. 6 , it is a fingerprint image of a normal finger obtained by the principle of reflected light imaging, and the imaging effect is good, which can be used for fingerprint identification of a normal finger.

When the finger is wet with water, that is, when the finger is wet, the valley line is filled with water. Since the refractive index of water is about 1.33, compared with the refractive index of air, the refractive index of water is related to the refractive index of the display screen 120 . If the ratio is closer, the intensity of the optical signal reflected from the fingerprint valley will be seriously attenuated when the finger is wetted with water. At this time, since the contrast of the intensity of the reflected light signal at the fingerprint ridge and the fingerprint valley is seriously reduced, the quality of the fingerprint image of the wet finger obtained according to the principle of reflected light imaging is very poor, as shown in FIG. 7 .

It can be seen that in the case of wet fingers, fingerprint recognition cannot be performed through the principle of reflected light imaging. In addition, 2D fake fingerprints can be imaged through the principle of reflected light imaging. The imaging effect is similar to that of real fingers, and there is a risk of being cracked by fake fingerprints.

To this end, the embodiments of the present application propose a fingerprint detection device and electronic equipment, which perform fingerprint identification through the principle of transmitted light imaging. The embodiments of the present application can be applied to the detection of various types of fingers, especially to the detection of wet fingers, and can also be used to prevent counterfeiting of 2D fake fingers, which can improve fingerprint recognition performance. The so-called wet fingers refer to the fingers that have been soaked in water or the fingers that are relatively wet.

Fingerprint identification is performed through the principle of transmitted light imaging. As shown in FIG. 8 , after the light signal emitted by the pixels in the self-luminous display screen 120 is transmitted into the finger, it is transmitted from the finger and passes through the display screen. Since the refractive index of the finger tissue is similar to that of the display screen, the intensity of the light signal transmitted from the ridge in the finger tissue is relatively high, and the intensity of the reflected light signal is relatively weak. The light in the finger tissue transmits from the valley and needs to pass through the skin and the air, the air and the display screen to enter the display screen, so that the intensity of the light signal transmitted from the valley of the fingerprint is weak, and the intensity of the reflected light signal is weak. higher. The contrast of the intensity of the optical signal transmitted from the ridge of the fingerprint and the valley of the fingerprint is about 50:1. Therefore, according to the difference in the intensity of the optical signal transmitted from the ridge of the fingerprint and the valley of the fingerprint, the difference between the intensity of the optical signal transmitted from the ridge of the fingerprint and the valley of the fingerprint can be obtained. A fingerprint image of considerable quality obtained by the principle of optical imaging for fingerprint identification, as shown in Figure 9. It can be seen that fingerprint recognition of normal fingers can be performed by the principle of transmitted light imaging.

When the finger is wet with water, the valley line of the fingerprint is filled with water, and the intensity of the light signal transmitted at the valley line will increase slightly, but the water in the valley line will have a certain loss of light, and the water and the display screen will be separated. There is still reflection on the interface, so that the intensity of the optical signal transmitted from the fingerprint ridge and the intensity of the optical signal transmitted from the fingerprint valley are still quite different, and the contrast ratio is about 20:1. It can be seen that the fingerprint recognition of wet fingers by the principle of transmitted light imaging can obtain a contrast ratio of 10 times the optical signal intensity obtained by the existing reflected light imaging principle, and can have better imaging quality, as shown in Figure 10. Show. Therefore, the fingerprint recognition performance of wet fingers can be improved by the principle of transmitted light imaging.

FIG. 11 shows a partial schematic diagram of the electronic device 20 according to an embodiment of the present application, which is a side view of the electronic device 20 ; FIG. 12 shows a front view of the electronic device 20 according to an embodiment of the present application. As shown in FIG. 11 and FIG. 12 , the electronic device 20 includes a display screen 200 and a fingerprint detection device 300 , and the display screen 200 is located above the fingerprint detection device 300 .

Specifically, the display screen 200 in FIG. 11 may represent a portion of the display screen 200, rather than the actual size and size of the display 200; FIG. 12 shows a front view of the display screen 200. The display screen 200 may correspond to the display screen 120 in the electronic device 10 described above in FIG. 1 and FIG. 2 , and is applicable to the above-mentioned related description of the display screen 120 , which is not repeated here for brevity.

In addition, the electronic device 20 of the embodiment of the present application is described by taking the display screen 200 including several light-emitting display pixels capable of self-emitting light as an example, and the light-emitting display pixels can be used for displaying images. As shown in FIG. 11 and FIG. 12 , the display screen 200 includes a fingerprint detection area 210 for finger pressing, that is, when the user needs to unlock the electronic device 20 or perform other fingerprint recognition, he only needs to press the finger on the The fingerprint detection area 210 can realize fingerprint input. The fingerprint detection area 210 may correspond to the fingerprint detection area 103 in the electronic device 10 described in FIG. 1 to FIG. 4 , and is applicable to the above related description about the fingerprint detection area 103 . For brevity, it is not repeated here.

In this embodiment of the present application, as shown in FIG. 12 , the display screen 200 includes a fingerprint detection area 210 , the fingerprint detection area 210 includes a first area 211 and a second area 212 , and the second area 212 surrounds the first area 211 , and the first area 211 and the second area 212 do not overlap.

It should be understood that a fingerprint detection device 300 is provided below the display screen 200 of the terminal device 20 in the embodiment of the present application, and the fingerprint detection device 300 can be used to receive an optical signal returned by a finger. Specifically, the fingerprint detection device 300 may include: an optical path guiding structure and an optical sensor, and the optical sensor is arranged below the optical path guiding structure.

The optical path guiding structure is used to guide the first return light signal formed by the finger above the display screen to the optical sensor, wherein the first return light signal is that the pixels 211 in the first area do not emit light, the The light emitted by the pixels 212 in the second area is transmitted into the finger, and then transmitted from the finger and passes through the light signal of the display screen.

Optionally, in one embodiment, the optical path guiding structure includes an optical lens, and the optical lens is arranged above the optical fingerprint sensor and is used for converging the first return light signal passing through the display screen to the sensing array of the optical fingerprint sensor.

Optionally, in one embodiment, the optical path guiding structure includes a microlens array with a plurality of microlenses and a light blocking layer with a plurality of microholes, and the microlens array is used to pass through the display screen. The first returned light signal is focused to the corresponding micro-holes of the light-blocking layer through the plurality of micro-lenses, and transmitted to the corresponding optical sensing units in the sensing array of the optical fingerprint sensor through the micro-holes .

The optical sensor is used for receiving the first return light signal passing through the light path guiding structure, and the first return light signal is used for acquiring the fingerprint image of the finger.

That is to say, in the case where the pixels in the first area 211 in the fingerprint detection area 210 do not emit light, and the pixels in the second area 212 emit light, the first return light signal is generated after the light is irradiated on the finger, and the first return light The signal is guided to the optical sensor through the optical path guiding structure to obtain the fingerprint image of the finger.

In the technical solution of the embodiment of the present application, the pixels in the first area of the fingerprint detection area do not emit light, and the light emitted by the pixels in the second area transmits into the finger, and then transmits from the finger and passes through the display screen , the transmitted light through the finger is detected to obtain the fingerprint pattern of the finger, the imaging quality is higher, the recognition ability of the wet finger can be improved, and the 2D fake finger can be anti-counterfeited. Therefore, the technical solution can improve the performance of fingerprint recognition.

Optionally, in order to avoid the reflected light signal generated after the light emitted by the pixels in the second area 212 irradiates the finger, the size of the first area 211 is not smaller than the diameter of the field of view of the fingerprint sensor. That is, the size of the first region 211 may be larger than the diameter of the field of view of the fingerprint sensor, or may be equal to the diameter of the field of view of the fingerprint sensor. It should be understood that the diameter of the field of view of the fingerprint sensor refers to the diameter of the corresponding area of the field of view of the fingerprint sensor on the upper surface of the display screen. For example, if the first area is a rectangle, the size of the size is the smallest value of the length or width of the rectangle.

Specifically, the vertical projection area of the first region may coincide with the vertical projection area of the field of view of the fingerprint sensor, or the vertical projection area of the first region may cover the vertical projection of the field of view of the fingerprint sensor area.

Optionally, considering that after the light emitted by the pixels in the second area 212 irradiates the finger, the light transmitted to the fingerprint sensor has a higher intensity, so as to facilitate the acquisition of the fingerprint image of the finger, the first area can be The dimension L of 211 satisfies:

D≤L≤D+2×d×tanα

Wherein, D represents the field of view diameter of the optical sensor, d represents the distance between the pixel in the second area 212 and the upper surface of the display screen, and α represents the light-emitting angle of the pixel.

For example, the light-emitting angle of the pixels in the display screen is between -60° and +60°. As shown in FIG. 13 , the size L of the first area 211 can satisfy:

D≤L≤D+2×d×tan60°

Optionally, the shape of the first region 211 may be circular or square. When the shape of the first area 211 is a circle, the diameter of the circle satisfies the above conditions; when the shape of the first area 211 is a square, the side length of the square can satisfy the above conditions. It should be understood that the shape of the first region can also be any other regular shape, for example, a regular hexagon and a regular octagon. This embodiment of the present application does not make any limitation on this.

Optionally, the boundary shape of the second area 212 (light-emitting area) may also be a circle or a square. The shape of the second region is preferably annular, and other shapes that can realize the technical solution of the present application are also possible. As shown in FIG. 14( a ) to FIG. 14 ( d ), it is a schematic diagram of the shape combination of the first area 211 and the second area 212 in the fingerprint detection area 210 .

Specifically, as shown in FIG. 14( a ), the combined shape of the first region and the second region is preferably concentric circles. Concentric circles are the more commonly used combined shapes.

As shown in 14(b), the first area is square, the second area surrounds the first area, and the second area is circular. In this embodiment, the center of the first area coincides with the center of the second area.

As shown in 14(c), the first area is circular, the second area surrounds the first area, and the second area is square. In this embodiment, the center of the first area coincides with the center of the second area.

As shown in 14(d), the first area is square, the second area surrounds the first area, and the second area is square. In this embodiment, the center of the first area coincides with the center of the second area.

The shape of the fingerprint detection area 210 in this embodiment of the present application may be set according to practical applications, and may be set to any regular shape. This embodiment of the present application does not make any limitation on this.

The shorter the wavelength of the light irradiating the finger, the shallower the light transmission depth in the finger, and the worse the effect of fingerprint imaging based on the transmitted light; the longer the wavelength of the light irradiating the finger, the deeper the light transmission depth in the finger, according to the transmitted light The better the effect of fingerprint imaging. Therefore, the pixels in the second area are preferably pixels that can emit red or yellow light. The pixels in the second area may also be pixels whose emitted light colors are other displayable colors, such as green, cyan, white, and the like. This embodiment of the present application does not make any limitation on this.

Optionally, the fingerprint detection device may further include an optical filter, the optical filter is located above the optical fingerprint sensor, and the optical filter is used to filter out other optical signals other than the first returned optical signal. For example, when the wavelength range of the first returned light signal is preferably 600-660 nm (red light band), the filter is used to filter out light whose wavelength is not equal to 600-660 nm. At this time, in addition to the red light source, a better fingerprint imaging effect can also be achieved by using other displayable color light sources.

The light intensity of the first returned light signal received by the optical sensor can also be used to determine whether the finger is a real finger.

Specifically, as shown in FIG. 11 , assuming that the finger touching the fingerprint detection area 210 is a real finger, the light signal emitted by the illuminated second area returns after being propagated by the finger, and the optical sensor can receive more However, in the case of 2D fake fingerprints, as shown in Figure 15, because the material of the 2D fake fingerprint is quite different from biological tissue, the optical signal cannot pass through the fake fingerprint for fingerprint imaging. Therefore, the light received by the optical sensor The signal mainly relies on the self-reflection of the fake fingerprint. No matter under the action of the oblique receiving optical path or the vertical receiving optical path, the optical sensor receives no optical signal or only a very small amount of the optical signal. That is to say, the intensity of the optical signal received by the fingerprint sensor is greater than that of a real finger, which is greater than that of a 2D fake fingerprint, so that the real and fake fingerprints can be distinguished according to this feature. Specifically, if the light intensity of the first return light signal received by the optical sensor is greater than or equal to a preset value, the finger is a real finger; if the first return light signal received by the optical sensor If the light intensity of the light signal is less than the preset value, the finger is a fake finger.

The electronic device 20 may include a processor for determining whether the finger is a real finger according to the light intensity of the first returned light signal received by the optical sensor. Specifically, the processor can be used to: if the light intensity of the first returned light signal received by the optical sensor is greater than or equal to a preset value, determine that the finger is a real finger; if the optical sensor receives The light intensity of the first returned light signal is less than the preset value, and it is determined that the finger is a fake finger.

It should be understood that the specific examples in the embodiments of the present application are only for helping those skilled in the art to better understand the embodiments of the present application, rather than limiting the scope of the embodiments of the present application.

It should be understood that the terms used in the embodiments of the present application and the appended claims are only for the purpose of describing specific embodiments, and are not intended to limit the embodiments of the present application. For example, as used in the embodiments of this application and the appended claims, the singular forms "a," "above," and "the" are intended to include the plural forms as well, unless the context clearly dictates otherwise.

Those of ordinary skill in the art can realize that the units of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of the two, in order to clearly illustrate the interchangeability of hardware and software In the above description, the components and steps of each example have been generally described in terms of function. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Skilled artisans may implement the described functionality using different methods for each particular application, but such implementations should not be considered beyond the scope of this application.

In the several embodiments provided in this application, it should be understood that the disclosed systems and apparatuses may be implemented in other manners. For example, the apparatus embodiments described above are only illustrative. For example, the division of the units is only a logical function division. In actual implementation, there may be other division methods. For example, multiple units or components may be combined or Can be integrated into another system, or some features can be ignored, or not implemented. In addition, the shown or discussed mutual coupling or direct coupling or communication connection may be indirect coupling or communication connection through some interfaces, devices or units, and may also be electrical, mechanical or other forms of connection.

The units described as separate components may or may not be physically separated, and components displayed as units may or may not be physical units, that is, may be located in one place, or may be distributed to multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solutions of the embodiments of the present application.

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

The integrated unit, if implemented in the form of a software functional unit and sold or used as an independent product, may be stored in a computer-readable storage medium. Based on this understanding, the technical solutions of the present application are essentially or part of contributions to the prior art, or all or part of the technical solutions can be embodied in the form of software products, and the computer software products are stored in a storage medium , including several instructions for causing a computer device (which may be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of the present application. The aforementioned storage medium includes: U disk, removable hard disk, Read-Only Memory (ROM, Read-Only Memory), Random Access Memory (RAM, Random Access Memory), magnetic disk or optical disk and other media that can store program codes.

The above are only specific embodiments of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art can easily think of various equivalents within the technical scope disclosed in the present application. Modifications or substitutions shall be covered by the protection scope of this application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.

Claims (16)

1. The utility model provides a fingerprint detection's device, its characterized in that is applicable to the below of display screen in order to realize optical fingerprint detection under the screen, the display screen includes fingerprint detection area, fingerprint detection area includes first region and second area, the second area encircles the first region, fingerprint detection's device includes:

an optical path guiding structure for guiding a first return light signal formed by a finger above the display screen to an optical sensor, wherein the first return light signal is a light signal in which pixels in the first area do not emit light, and light emitted by pixels in the second area is transmitted into the finger, and then transmitted out of the finger and through the display screen;

an optical sensor disposed below the optical path guide structure for receiving the first return light signal passing through the optical path guide structure, the first return light signal being used to acquire a fingerprint image of the finger.

2. The apparatus of claim 1, wherein the first area is sized to be no smaller than a diameter of a field of view of the fingerprint sensor.

3. The apparatus of claim 1, wherein a perpendicular projected area of the first region coincides with a perpendicular projected area of a field of view of the fingerprint sensor, or wherein the perpendicular projected area of the first region covers the perpendicular projected area of the field of view of the fingerprint sensor.

4. The device according to claim 1 or 2, wherein the dimension L of the first area satisfies:

D≤L≤D+2×d×tanα

wherein D is a field diameter of the optical sensor, D is a distance from the pixel in the second region to the upper surface of the display screen, and a represents a light emitting angle of the pixel.

5. The device of any one of claims 1 to 4, wherein the first region is circular or square in shape and the second region is circular or square in shape at its border.

6. The device of claim 5, wherein the combined shape of the first region and the second region is concentric circles.

7. The device according to any one of claims 1 to 6, wherein the light emitted by the pixels in the second region is red or yellow.

8. The apparatus of any one of claims 1 to 6, further comprising:

and the optical filter is positioned above the optical fingerprint sensor and used for filtering other optical signals except the first return optical signal.

9. The apparatus of claim 8, wherein the first return light signal has a wavelength in the range of 600-660 nm, and the filter is configured to filter light having a wavelength not equal to 600-660 nm.

10. The apparatus of any one of claims 1-9, wherein the optical path directing structure comprises an optical lens disposed above the optical fingerprint sensor for focusing the first return optical signal passing through the display screen onto a sensing array of the optical fingerprint sensor.

11. The apparatus according to any one of claims 1 to 9, wherein the optical path guiding structure comprises a microlens array having a plurality of microlenses and a light-blocking layer having a plurality of micro-holes, and the microlens array is configured to focus the first return optical signal passing through the display screen to the corresponding micro-holes of the light-blocking layer through the plurality of microlenses, respectively, and transmit the first return optical signal to the corresponding optical sensing units in the sensing array of the optical fingerprint sensor through the micro-holes.

12. The apparatus of any one of claims 1 to 11, wherein the intensity of the first return light signal received by the optical sensor is used to determine whether the finger is a real finger.

13. The apparatus according to claim 12, wherein if the light intensity of the first return light signal received by the optical sensor is greater than or equal to a preset value, the finger is a real finger;

and if the light intensity of the first return light signal received by the optical sensor is smaller than the preset value, the finger is a fake finger.

14. An electronic device comprising a display screen and an apparatus for fingerprint detection according to any one of claims 1 to 12, said apparatus being arranged below said display screen to enable an off-screen optical fingerprint detection.

15. The electronic device of claim 14, further comprising: and the processor is used for determining whether the finger is a real finger or not according to the light intensity of the first return light signal received by the optical sensor.

16. The electronic device of claim 15, wherein the processor is specifically configured to:

if the light intensity of the first return light signal received by the optical sensor is greater than or equal to a preset value, determining that the finger is a true finger;

and if the light intensity of the first return light signal received by the optical sensor is smaller than the preset value, determining that the finger is a fake finger.

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