Fingerprint Recognition Device and Electronic Device

Abstract

An embodiment of the present application provides a fingerprint recognition device and an electronic device. The fingerprint recognition device includes a fingerprint recognition module, and the fingerprint recognition module includes a fingerprint sensor and a metasurface optical element; the metasurface optical element is located on the light incident side of the fingerprint sensor and is used to guide fingerprint detection light to the fingerprint sensor, and the fingerprint sensor is used to obtain a fingerprint image of a finger according to the fingerprint detection light. Based on meeting the optical path design requirements of the optical fingerprint recognition device, the metasurface optical element in the present application helps to reduce the size of the stacked structure of the fingerprint recognition device and the thinning of the electronic device.

Description

Technical Field

[0001] This application relates to the field of biometric technologies, and particularly to a fingerprint recognition device and an electronic device. Background Art

[0002] With the increasing popularity of electronic devices, the popularity of biometric technologies in daily life has increased significantly. Due to its particularity, fingerprint features are of great significance in both recognition and information security.

[0003] People's requirements for optical fingerprint recognition have also increased significantly. Among them, the optical fingerprint recognition effect and its appearance are two key aspects for evaluating electronic devices. A too large stacking size of the optical fingerprint recognition device will affect the appearance experience of the electronic device. Currently, existing fingerprint recognition devices include a lens disposed below the display screen and a lens barrel for fixing the lens. The lens is used to receive the optical signal formed by reflection from a human finger above the display screen to detect the biometric information of the finger. Although optical fingerprint recognition devices have not been popularized in existing high-end electronic devices, due to their simple operation, less impact on the appearance of electronic devices equipped with optical fingerprint recognition devices, and the ability to meet the needs of users for controlling various electronic devices, the trend of using optical fingerprint recognition devices in future high-end intelligent terminals is becoming more and more obvious.

[0004] However, the stacking structure of the existing fingerprint recognition device has a large size (i.e., a relatively large height). On the basis of meeting the optical path design requirements of the optical fingerprint recognition device, the stacking structure has high requirements for the assembly process and space, and is likely to affect the overall architecture design of the machine. Summary of the Invention

[0005] This application provides a fingerprint recognition device and an electronic device, which can reduce the size of the stacking structure of the fingerprint recognition device and contribute to the thinning and lightening of the electronic device.

[0006] In a first aspect of an embodiment of this application, a fingerprint recognition device is provided, which includes a fingerprint recognition module. The fingerprint recognition module includes a fingerprint sensor and a metasurface optical element. The metasurface optical element is located on the light incident side of the fingerprint sensor and is used to guide the fingerprint detection light transmitted through the display screen to the fingerprint sensor. The fingerprint sensor is used to obtain a fingerprint image of a finger according to the fingerprint detection light. Among them, the fingerprint detection light is a detection light carrying fingerprint information formed by reflection from a finger.

[0007] In this application, a metasurface optical element is disposed on the light incident side of the fingerprint sensor, and the metasurface optical element guides the fingerprint detection light to the fingerprint sensor, so that the fingerprint sensor can acquire the fingerprint image of the finger. On the one hand, due to the ultra-thin and miniaturized characteristics of the metasurface optical element, it helps to reduce the size of the stacked structure of the fingerprint recognition device. On the basis of meeting the optical path design requirements of the optical fingerprint recognition device, it can reduce the requirements for the assembly process and space of the stacked structure, and contribute to the thinness and lightness of the electronic device. On the other hand, compared with the fingerprint recognition device in the prior art, in this application, the metasurface optical element can improve the transmittance of the fingerprint detection light, so as to improve the light utilization rate of the fingerprint detection light, make the fingerprint information obtained by the fingerprint sensor more stable, enhance the fingerprint recognition effect and the quality of the processed fingerprint image, and further improve the user's fingerprint recognition experience in complex environments.

[0008] In a possible implementation manner, the metasurface optical element includes a substrate and a microstructure array. The microstructure array is located on the substrate and is used to converge the fingerprint detection light to the fingerprint sensor. In this way, the microstructure array can play a guiding role in the fingerprint detection light, guide or converge the fingerprint detection light passing through the microstructure array to the fingerprint sensor, so that the fingerprint sensor can acquire the fingerprint image and realize fingerprint recognition.

[0009] In a possible implementation manner, the microstructure array includes a plurality of microstructure units with a preset shape. Each microstructure unit includes a plurality of microstructures, and the plurality of microstructures are arranged to form a microstructure unit with a preset shape.

[0010] In this way, through the microstructure unit, the microstructures are regularly arranged on the substrate. While realizing the convergence of the fingerprint detection light to the fingerprint sensor, the arrangement mode of the microstructures on the substrate, the shape of the microstructure unit, and the distance between the centers of two adjacent microstructure units can be changed to meet different optical path design requirements.

[0011] In a possible implementation manner, the preset shape is a quadrilateral or a hexagon. On the one hand, this can make the microstructure units in the microstructure array be regularly arranged on the substrate, so that the fingerprint detection light can be transmitted to the fingerprint sensor according to the preset optical path design. While realizing the guiding of the fingerprint detection light by the microstructure array, the fingerprint recognition effect is improved; on the other hand, it can make the structures of the microstructure unit and the microstructure array more diverse.

[0012] In a possible implementation manner, the refractive index of the microstructure is greater than the refractive index of the substrate. In this way, the microstructure and the substrate have different refractive indexes for the fingerprint detection light, and the optical path of the fingerprint detection light propagating to the fingerprint sensor can be corrected to achieve the required effect.

[0013] In a possible implementation, the microstructures are nano-scale micro-columns. This can enable the metasurface optical element to have the characteristics of being ultra-thin and miniaturized, which helps to reduce the size of the stacked structure of the fingerprint recognition device, thereby contributing to the thinning and lightening of the electronic device.

[0014] In a possible implementation, the micro-columns have a rotationally symmetric structure. On the one hand, this can facilitate the processing of the micro-columns to reduce the manufacturing difficulty and cost of the metasurface optical element and the fingerprint recognition device. On the other hand, it can make the fingerprint detection light converged by the micro-columns more regular.

[0015] In a possible implementation, the micro-columns are cylinders, cubes or hexahedrons. This can make the structure of the micro-columns and the micro-structure array more diverse while realizing the guiding of the fingerprint detection light.

[0016] In a possible implementation, the structural period of the metasurface optical element is less than or equal to 1 / 2 wavelength of the fingerprint detection light, and the structural period is the distance between the centers of two adjacent micro-structure units. This can enable the micro-structures to be densely arranged on the substrate, which can improve the light intensity of the fingerprint detection light passing through the micro-structures. Furthermore, the fingerprint detection light has a high light utilization rate, thus contributing to the improvement of the fingerprint recognition effect.

[0017] In a possible implementation, the height of the micro-structure is greater than 1 / 2 wavelength of the fingerprint detection light. This can extend the transmission path of the fingerprint detection light in the micro-structure or increase the probability of the fingerprint detection light passing through the micro-structure, so that the metasurface optical element has a better converging effect on the fingerprint detection light, further improving the fingerprint recognition effect and then enhancing the user's fingerprint recognition experience in complex environments.

[0018] In a possible implementation, the structural period of the metasurface optical element is 100nm - 500nm, and the height of the micro-structure is 300nm - 500nm. This can achieve a better converging effect on the fingerprint detection light while enabling the metasurface optical element to have the characteristics of being ultra-thin and miniaturized.

[0019] In a possible implementation, the fingerprint recognition device is located on the side of the display screen of the electronic device facing the inside of the electronic device, the metasurface optical element is located between the fingerprint sensor and the display screen, the display screen has a fingerprint recognition area, and at least part of the fingerprint recognition area is located in the display area of the display screen.

[0020] In this way, on the basis of realizing fingerprint recognition, since the metasurface optical element is arranged between the fingerprint sensor and the display screen instead of being coupled to the display screen, it is convenient for the later maintenance of the fingerprint recognition device or the repair of the display screen, reducing the later maintenance cost of the electronic device.

[0021] In a possible implementation, the distance between the side of the metasurface optical element facing the fingerprint sensor and the fingerprint sensor is 0.005 mm - 0.3 mm, and the distance between the side of the metasurface optical element facing the display screen and the outer surface on the fingerprint recognition area is 0.5 mm - 2 mm.

[0022] On the one hand, this can meet the requirements of the optical path design and the imaging of the fingerprint sensor. On the other hand, without changing the overall thickness of the electronic device, since the metasurface optical element is used, the fingerprint recognition device has the characteristics of being thin, light, and miniaturized, which can make the distance between the metasurface optical element and the display screen relatively large, helping to reduce the assembly process of the fingerprint recognition device.

[0023] In a possible implementation, the side of the substrate facing the display screen is provided with a microstructure array, or

[0024] the side of the substrate facing the fingerprint sensor is provided with a microstructure array, or

[0025] both the side of the substrate facing the display screen and the side of the substrate facing the fingerprint sensor are provided with microstructure arrays.

[0026] In this way, on the basis of realizing under-screen fingerprint recognition, on the one hand, it makes the metasurface optical element and the fingerprint recognition device more diverse. On the other hand, it enables the fingerprint recognition device to be applicable to different application scenarios to improve the applicability of the fingerprint recognition device.

[0027] In a possible implementation, the metasurface optical element is a single-sided metasurface lens or a double-sided metasurface lens. This can make the design of the metasurface optical element more diverse and enable the fingerprint recognition device to have a wider range of applicability.

[0028] In a possible implementation, the metasurface optical element is bonded to the fingerprint sensor through an adhesive layer, where the thickness of the adhesive layer is 0.005 mm - 0.3 mm. On the one hand, this can fix the metasurface optical element on the fingerprint sensor through the adhesive layer. On the other hand, it can meet the requirements for the image distance during imaging by adjusting the thickness of the adhesive layer.

[0029] In a possible implementation, the thickness of the fingerprint recognition module is less than or equal to 1 mm, where the thickness of the metasurface optical element is less than or equal to 200 μm. On the one hand, this helps to reduce the assembly process of the fingerprint recognition device. On the other hand, it helps to make the electronic device thinner and lighter.

[0030] In a possible implementation, when the display screen is an OLED display screen, the fingerprint detection light is the monochromatic light emitted by the OLED display screen, which is formed by the finger on the fingerprint recognition area and is used for fingerprint recognition. This can avoid interference from other monochromatic lights in the visible light on the fingerprint recognition effect, so as to improve the fingerprint recognition effect.

[0031] In a possible implementation, when the display screen is a liquid crystal display screen, the fingerprint recognition device further includes a detection light source, and the detection light source is located on the side of the fingerprint sensor. At the same time, the metasurface optical element is located outside the light emitting area of the detection light source, so that the detection light emitted by the detection light source irradiates the fingerprint recognition area.

[0032] On the one hand, this can avoid the metasurface optical element from blocking the light emitting area of the detection light source, enhance the light intensity of the finger above the fingerprint recognition area, so as to improve the light utilization rate and the fingerprint recognition effect; on the other hand, it can make the setting methods of the detection light source and the fingerprint recognition device more diverse.

[0033] In a possible implementation, the wavelength of the detection light is different from that of the display light for screen display. This can avoid the detection light emitted by the detection light source from interfering with the display effect of the liquid crystal display screen.

[0034] In a possible implementation, the detection light source is an infrared light source and the display light is visible light. In this way, the user cannot see or perceive the detection light for fingerprint recognition through the liquid crystal display screen, and it can avoid the detection light emitted by the detection light source from affecting the display effect of the image.

[0035] In a possible implementation, the fingerprint recognition module further includes a filter element for filtering the fingerprint detection light.

[0036] The filter element is located inside or on the surface of the protective cover plate of the display screen, or

[0037] The filter element is located inside or on the surface of the metasurface optical element, or

[0038] The filter element is located on the surface of the fingerprint sensor.

[0039] In this way, other infrared lights or interference lights outside the wavelength band of the fingerprint detection light can be filtered by the filter element, so as to improve the fingerprint recognition effect while making the setting method of the filter element more diverse.

[0040] In a possible implementation, the filter element is a filter film layer formed by coating or plating. This can make the filter element fit better with the protective cover plate, the metasurface optical element or the fingerprint sensor.

[0041] The second aspect of the embodiments of the present application provides an electronic device, which includes: a display screen, and a fingerprint recognition device as described in any one of the above, wherein the fingerprint recognition device is located on the side of the display screen facing the inside of the electronic device.

[0042] In this way, through the metasurface optical element in the fingerprint recognition device, the fingerprint detection light is guided to the fingerprint sensor, so that the fingerprint sensor can obtain the fingerprint image of the finger. On the one hand, it can reduce the size of the stacked structure of the fingerprint recognition device. On the basis of meeting the optical path design requirements of the optical fingerprint recognition device, it can reduce the requirements for the assembly process and space of the stacked structure, which helps to make the electronic device thinner and lighter; on the other hand, it can improve the light utilization rate of the fingerprint detection light, make the fingerprint information obtained by the fingerprint sensor more stable, enhance the fingerprint recognition effect and the quality of the processed fingerprint image, and thus improve the user's fingerprint recognition experience in complex environments. Description of the Drawings

[0043] Figure 1 It is a schematic structural diagram of an electronic device provided by an embodiment of the present application;

[0044] Figure 2 is Figure 1 The split structural diagram when the electronic device in is a mobile phone;

[0045] Figure 3 It is a schematic principle diagram of an electronic device equipped with a fingerprint recognition device provided by an embodiment of the present application;

[0046] Figure 4 It is a schematic structural diagram of a microstructure array provided by an embodiment of the present application;

[0047] Figure 5 It is a schematic structural diagram of another microstructure array provided by an embodiment of the present application;

[0048] Figure 6 It is a schematic structural diagram of a metasurface optical element provided by an embodiment of the present application;

[0049] Figure 7 It is a schematic structural diagram of another metasurface optical element provided by an embodiment of the present application;

[0050] Figure 8 It is a schematic structural diagram of yet another metasurface optical element provided by an embodiment of the present application;

[0051] Figure 9 It is a schematic structural diagram of yet another metasurface optical element provided by an embodiment of the present application;

[0052] Figure 10 It is a schematic structural diagram of another electronic device equipped with a fingerprint recognition device provided by an embodiment of the present application;

[0053] Figure 11 Schematic diagram of the split structure of the transparent protection cover plate and the display module in the display screen of the electronic device provided by the embodiment of the present application;

[0054] Figure 12 Schematic diagram of the structure of the first setting method of the filter element provided by the embodiment of the present application;

[0055] Figure 13 Schematic diagram of the structure of the second setting method of the filter element provided by the embodiment of the present application;

[0056] Figure 14 Schematic diagram of the structure of the third setting method of the filter element provided by the embodiment of the present application;

[0057] Figure 15 Schematic diagram of the structure of the fourth setting method of the filter element provided by the embodiment of the present application;

[0058] Figure 16 Schematic diagram of the split structure of the transparent protection cover plate, liquid crystal panel and backlight element of the electronic device provided by the embodiment of the present application;

[0059] Figure 17 Schematic diagram of the principle of another electronic device equipped with a fingerprint recognition device provided by the embodiment of the present application.

[0060] Explanation of reference numerals:

[0061] 100 - mobile phone; 10 - display screen; 10a - OLED display screen; 10b - liquid crystal display screen; 11 - protection cover plate; 12 - display module; 121 - liquid crystal panel; 122 - backlight element; 13 - display area; 14 - non - display area; 15 - fingerprint recognition area; 20 - fingerprint recognition module; 21 - metasurface optical element; 211 - substrate; 212 - micro - structure unit; 2121 - micro - structure; 22 - fingerprint sensor; 23 - detection light source; 24 - adhesive layer; 25 - filter element; 26 - second circuit board; 30 - middle frame; 31 - metal middle plate; 32 - frame; 40 - first circuit board; 50 - battery; 60 - rear cover; 200 - finger. Detailed implementation manners

[0062] The terms used in the implementation manners part of the present application are only used to explain the specific embodiments of the present application, rather than intended to limit the present application.

[0063] At present, in electronic devices, optical fingerprint recognition devices are widely favored because they can be installed at any position of the electronic device (such as a mobile phone), enabling the electronic device to achieve a higher screen-to-body ratio and contributing to the realization of a full-screen electronic device. When using the electronic device to collect fingerprint images, the light reflected from the surface of the finger is received by the fingerprint sensor to obtain fingerprint information. Since the reflected light is greatly affected by the surrounding environment, when the surrounding environment changes, the quality of the collected fingerprint information varies greatly, which will affect the stability of the fingerprint information obtained by the fingerprint sensor and further affect the recognition effect. In addition, the stacking size (i.e., the structural size) of the optical fingerprint recognition device is too large. On the basis of meeting the optical path design requirements of the optical fingerprint recognition device, it is easy to make the thickness of the whole machine larger, affecting the appearance experience of the electronic device and the user experience. Therefore, the requirements for optical fingerprint recognition have also been significantly improved.

[0064] The optical fingerprint recognition effect and its appearance are two key aspects for the inspection of electronic devices. In the current prior art, an in-screen biometric recognition device generally includes: a lens disposed under the display screen of the electronic device and a lens barrel for fixing the lens. The lens is used to receive the optical signal formed by reflection from the human finger above the display screen and use this optical signal to detect the biometric information of the finger to obtain the fingerprint information of the human body; among them, the lens barrel is fixed by a bracket.

[0065] However, this solution uses the imaging method of a traditional camera (such as a 3P lens). On the one hand, it makes the stacking size of the fingerprint recognition device relatively large (i.e., the height is relatively large). On the basis of meeting the optical path design requirements of the optical fingerprint recognition device (such as the upper surface of the optical fingerprint recognition device in this case is 1.3 mm away from the lower surface of the display screen), it is easy to affect the overall architecture design of the whole machine (such as making the thickness of the whole machine larger), thus affecting the user experience; on the other hand, it is inevitably affected by the difference in the relative illumination (abbreviation: RI) value between the four corners and the center of the lens, resulting in insufficient signal volume around after processing, so it cannot be used for fingerprint recognition.

[0066] It should be noted that in the prior art, according to the structure of the lens, the lens generally can be represented by a combination such as 1P, 2P, 3P, 3P....1G, 2G, 3G... or 1P2G. Among them, P represents a plastic lens, G represents a glass lens, and the number in front of P or G is the number of lenses in the lens. For example, 2P can be understood as the lens is composed of two plastic lenses.

[0067] In the prior art, the definition of illuminance is the degree of brightness presented by an object or a surface being illuminated by a light source. The relative illuminance is the ratio of the central illuminance to the peripheral illuminance. A too high relative illuminance means that the center of the image is brighter and the surrounding is darker. Therefore, in the prior art, the lens will inevitably be affected by the difference in RI values between the four corners and the center of the lens, resulting in a darker surrounding of the lens (i.e., the light intensity for fingerprint recognition at the four corners of the lens is weaker), and thus causing insufficient signal volume at the surrounding after processing, which cannot be used for fingerprint recognition.

[0068] For this reason, the embodiments of the present application provide a fingerprint recognition device and an electronic device, which helps to reduce the stacking size of the fingerprint recognition device, improve the fingerprint recognition effect, and enhance the fingerprint recognition experience of users in complex environments (such as the state of wet fingers, etc.).

[0069] Among them, in this embodiment, the electronic device may include, but is not limited to, mobile or fixed terminals with fingerprint recognition functions such as mobile phones, tablet computers, laptop computers, ultra-mobile personal computers (UMPCs), handheld computers, walkie-talkies, netbooks, POS machines, personal digital assistants (PDAs), wearable devices, virtual reality devices, etc.

[0070] Next, taking a mobile phone as an example in the embodiments of the present application, the electronic device equipped with the fingerprint recognition device in the present application will be further described.

[0071] In the embodiments of the present application, taking the mobile phone 100 as the above-mentioned electronic device as an example for description, Figure 1 and Figure 2 respectively show the overall and split structures of the mobile phone 100. Refer to Figure 1 As shown, the display screen 10 of the mobile phone 100 provided in the embodiments of the present application can be a water-drop screen, a notch screen or a hole-punch screen. The following description will take the notch screen as an example for illustration. Refer to Figure 2 As shown, the mobile phone 100 may include: a display screen 10 and a rear cover 60. A middle frame 30, a first circuit board 40 and a battery 50 may be arranged between the display screen 10 and the rear cover 60. Among them, the first circuit board 40 and the battery 50 may be arranged on the middle frame 30. For example, the first circuit board 40 and the battery 50 may be arranged on the side of the middle frame 30 facing the rear cover 60, or the first circuit board 40 and the battery 50 may be arranged on the side of the middle frame 30 facing the display screen 10.

[0072] The battery 50 can be connected to the charging management module and the first circuit board 40 through the power management module. The power management module receives the inputs from the battery 50 and / or the charging management module and supplies power to the processor, the internal memory, the external memory, the display screen 10, the camera, and the communication module, etc. The power management module can also be used to monitor one or more parameters such as the capacity of the battery 50, the number of battery 50 charge cycles, and the health status of the battery 50 (leakage, impedance). In some other embodiments, the power management module can also be disposed in the processor of the first circuit board 40. In some other embodiments, the power management module and the charging management module can also be disposed in the same device.

[0073] The display screen 10 can be used to display the information input by the user or the information provided to the user as well as various menus of the electronic device, and can also accept user input. The display screen 10 can be an Organic Light-Emitting Diode (OLED) display screen or a Liquid Crystal Display (LCD). It should be noted that the display screen 10 can be a flat screen or a curved screen. In this embodiment, the display screen 10 is taken as an example of a flat screen to illustrate the electronic device such as the mobile phone 100. Refer to Figure 1 As shown, when the display screen 10 is a flat screen, a display area 13 and a non-display area 14 are provided on the display screen 10. Among them, the display area 13 is the area on the display screen 10 or the mobile phone 100 for displaying images. Correspondingly, the non-display area 14 is the non-image display area on the display screen 10 or the mobile phone 100, and the non-display area 14 is located on the periphery of the display area 13.

[0074] The rear cover 60 can be a metal rear cover, a glass rear cover, a plastic rear cover, or a ceramic rear cover. In the embodiments of the present application, the material of the rear cover 60 is not limited.

[0075] The middle frame 30 can include a metal middle plate 31 and a frame 32. The frame 32 is arranged around the outer periphery of the metal middle plate 31 for one week. Generally speaking, the frame 32 can include a top frame, a bottom frame, a left frame, and a right frame, and the top frame, the bottom frame, the left frame, and the right frame enclose a frame 32 in a square ring structure. Among them, the metal middle plate 31 can be an aluminum plate, an aluminum alloy, or a magnesium alloy. The frame 32 can be a metal frame or a ceramic frame. Among them, the metal middle frame 30 and the frame 32 can be snap-connected, welded, bonded, or integrally formed, or the metal middle frame 30 and the frame 32 are fixedly connected by injection molding.

[0076] It should be noted that, in some examples, the rear cover 60 of the mobile phone 100 can be connected to the frame 32 to form an integrally molded (Unibody) rear cover. For example, the mobile phone 100 may include: a display screen 10, a metal middle plate 31, and a battery cover, and the battery cover can be a rear cover formed by integrally molding (Unibody) the frame 32 and the rear cover 60. In this way, the first circuit board 40 and the battery 50 are located in the space surrounded by the metal middle plate 31 and the battery cover.

[0077] It can be understood that the structure illustrated in the embodiments of the present application does not constitute a specific limitation on the mobile phone 100. In other embodiments of the present application, the mobile phone 100 may include more or fewer components than those illustrated, or combine certain components, or split certain components, or have different component arrangements. The illustrated components can be implemented in hardware, software, or a combination of software and hardware.

[0078] To implement the fingerprint recognition function, as Figure 2 shown, the mobile phone 100 further includes a fingerprint recognition device located under the display screen 10. A fingerprint recognition area 15 corresponding to the fingerprint recognition device can be set on the display screen 10 of the electronic device, so that a finger can be placed on and in contact with the fingerprint recognition area 15 for fingerprint recognition. It should be noted that, in some other examples, the setting position of the fingerprint recognition area 15 includes but is not limited to on the display screen 10 as Figure 2 shown. For example, the fingerprint recognition area 15 can also be set on the frame 32 or the rear cover 60.

[0079] The fingerprint recognition device in the present application will be further described below.

[0080] Figure 3 It is a schematic diagram of the principle of an electronic device equipped with a fingerprint recognition device provided by an embodiment of the present application.

[0081] Refer to Figure 3 shown, the fingerprint recognition device is applied to an electronic device with a display screen 10. The fingerprint recognition device may include a fingerprint recognition module 20 located under the display screen 10. The display screen 10 has a fingerprint recognition area 15, and at least part of the fingerprint recognition area 15 is located in the display area 13 of the display screen 10 (see Figure 1As shown in [figure]. For example, the fingerprint recognition area 15 may be located on the display area 13, or a partial area of the fingerprint recognition area 15 is located on the display area 13 and a partial area is located on the non-display area 14, so as to increase the area of the display area 13 on the display screen 10, which helps to realize the full-screen of an electronic device (such as a mobile phone 100, etc.), thereby obtaining a better user experience. Among them, the fingerprint recognition module 20 may include a fingerprint sensor 22 and a metasurface optical element 21; the metasurface optical element 21 is located on the light incident side of the fingerprint sensor 22. When the fingerprint recognition device is applied to an electronic device such as a mobile phone 100, the fingerprint recognition device may be located on the side of the display screen of the electronic device facing the inside of the electronic device. At this time, the metasurface optical element 21 may be located between the fingerprint sensor 22 and the display screen 10. In this way, the metasurface optical element 21 can be used to guide the fingerprint detection light passing through the display screen 10 to the fingerprint sensor 22, and the fingerprint sensor 22 is used to obtain the fingerprint image of the finger 200 according to the fingerprint detection light. When the finger 200 is placed on the fingerprint recognition area 15 for fingerprint recognition, the fingerprint detection light is the detection light carrying fingerprint information formed by being reflected by the finger 200.

[0082] Among them, the light incident side can be understood as the side where the fingerprint detection light enters on the fingerprint sensor 22. In practical applications, the light incident side of the fingerprint sensor 22 can be understood as the side of the fingerprint sensor 22 facing the display screen 10. It should be noted that in this embodiment, the fingerprint recognition area 15 may specifically be an area for a user to contact the finger 200 to implement a fingerprint input operation.

[0083] Among them, in this embodiment, the metasurface optical element 21 may be an optical element based on a metasurface. Among them, a metasurface is a two-dimensional planar structure composed of artificial atoms with special electromagnetic properties arranged in a certain pattern, which can realize flexible control of the amplitude, phase, polarization, etc. of incident light and has a powerful light field manipulation ability. Since the metasurface optical element 21 is an optical element based on a metasurface, the metasurface optical element 21 has the characteristics of being ultra-thin and miniaturized compared with a traditional lens on the basis of realizing the convergence and guidance of the fingerprint detection light passing through the display screen 10 to the fingerprint sensor 22. Specifically, referring to Figure 3 As shown, in this application, the metasurface optical element 21 is arranged between the fingerprint sensor 22 and the display screen 10 instead of being coupled to the display screen 10, which is convenient for the later maintenance of the fingerprint recognition device or the repair of the display screen 10, and further reduces the later maintenance cost of the mobile phone 100.

[0084] It should be noted that in the fingerprint recognition device according to the embodiments of the present application, the fingerprint detection light formed by the finger 200 on the fingerprint recognition area 15 and transmitted through the display screen 10 is directly guided to the fingerprint sensor 22 by the metasurface optical element 21, so that the fingerprint sensor 22 can obtain the fingerprint image of the finger 200, thereby performing fingerprint recognition. Therefore, the fingerprint recognition device of the present application can improve the transmittance of the fingerprint detection light, so that the light intensity of the fingerprint detection light for fingerprint recognition guided to the fingerprint sensor 22 is greater, so as to improve the light utilization rate of the fingerprint detection light, enhance the fingerprint recognition effect, and further improve the fingerprint recognition experience of the user in a complex environment (such as when the finger 200 is wet).

[0085] Among them, in this embodiment, the object-image ratio (that is, the ratio between an object and the image of the object) of the fingerprint sensor 22 and the fingerprint recognition area 15 (that is, the fingerprint acquisition area) is greater than 1:1 and less than or equal to 2:1. That is to say, in the fingerprint recognition device of this embodiment, the ratio of the finger 200 to the image of the finger 200 formed on the fingerprint sensor 22 is greater than 1:1 and less than or equal to 2:1, so that the sensing area of the fingerprint sensor 22 is relatively smaller than the sensor area when the object-image ratio is 1:1 in the prior art, thereby further reducing the costs of the fingerprint recognition module 20 and the electronic device.

[0086] Compared with traditional lenses, the metasurface optical element 21 has the characteristics of being ultra-thin and miniaturized, which helps to realize the thinning of the fingerprint recognition module 20 equipped with the metasurface optical element 21. Compared with the prior art, the metasurface optical element 21 helps to reduce the size of the stacked structure of the fingerprint recognition device. That is to say, the metasurface optical element 21 can reduce the height of the fingerprint recognition device, facilitate the assembly of the fingerprint recognition device in the mobile phone 100, and can reduce the requirements of the stacked structure of the fingerprint recognition device for the assembly process and space on the basis of meeting the optical path design requirements of the optical fingerprint recognition device.

[0087] Among them, in this embodiment, the fingerprint sensor 22 can also be referred to as an optical sensor, an image sensor, an optical fingerprint sensor, an optical sensor, or a fingerprint detection sensor, etc. It may specifically include an optical imaging chip, or an optical imaging chip with a certain optical stack, and it has an optical sensing array with a plurality of optical sensing units for receiving fingerprint detection light and performing photoelectric conversion on the fingerprint detection light. In this embodiment, the fingerprint sensor 22 can refer to the structure of the optical fingerprint sensor 22 in the prior art, and in this embodiment, it will not be further elaborated.

[0088] Specifically, in this embodiment, the fingerprint recognition module 20 may be a modular structure. For example, the fingerprint recognition module 20 may be an integrated structure formed by encapsulation. It should be noted that the fingerprint recognition module 20 in this embodiment is mainly designed for narrow-band light sources, where the narrow-band light sources may be light sources including the wavelength ranges of visible light and infrared light, such as green light with a wavelength of 525 nm or infrared light with a wavelength of 940 nm.

[0089] As a possible implementation manner, in this embodiment, the fingerprint recognition module 20 may be disposed on the middle frame 30 of the mobile phone 100 or other positions inside the electronic device. Exemplarily, when the fingerprint recognition module 20 is disposed on the middle frame 30 of the mobile phone 100, the fingerprint recognition module 20 may be embedded in the middle frame 30, that is, the fingerprint recognition module 20 may be located inside the middle frame 30. Or, the fingerprint recognition module 20 may be fixed on the side of the middle frame 30 facing away from the display screen 10, that is, the fingerprint recognition module 20 is fixed on the side of the middle frame 30 facing the rear cover 60. Or, the fingerprint recognition module 20 may also be fixed on the side of the middle frame 30 close to the display screen 10, that is, the fingerprint recognition module 20 is fixed on the side of the middle frame 30 facing the display screen 10. In this embodiment, the fixing manner of the fingerprint recognition module 20 is not further limited.

[0090] In this application, the metasurface optical element 21 is disposed between the fingerprint sensor 22 and the display screen 10, and the fingerprint detection light transmitted through the display screen 10 is guided to the fingerprint sensor 22 through the metasurface optical element 21 to obtain the fingerprint image of the finger 200. On the one hand, because the metasurface optical element 21 has the characteristics of being ultra-thin and miniaturized, it helps to reduce the size of the stacked structure of the fingerprint recognition device. On the basis of meeting the optical path design requirements of the optical fingerprint recognition device, it can reduce the requirements for the assembly process and space of the stacked structure, and contribute to the thinning of the electronic device. On the other hand, it can improve the transmittance of the fingerprint detection light, make the light intensity of the fingerprint detection light for fingerprint recognition guided to the fingerprint sensor 22 greater, so as to improve the light utilization rate of the fingerprint detection light, make the fingerprint information obtained by the fingerprint sensor 22 more stable, enable the fingerprint sensor 22 to have sufficient information for image processing to utilize, enhance the fingerprint recognition effect and the quality of the processed fingerprint image, and further improve the user's fingerprint recognition experience in a complex environment. In addition, because the metasurface optical element 21 is disposed between the fingerprint sensor 22 and the display screen 10, rather than being coupled to the display screen 10, it is convenient for the later maintenance of the fingerprint recognition device or the repair of the display screen 10, and reduces the later maintenance cost of the mobile phone 100.

[0091] Reference Figure 3As shown, in this embodiment, the metasurface optical element 21 may include a substrate 211 and a microstructure array (not labeled in the figure) located on the substrate 211. The microstructure array is used to converge the fingerprint detection light onto the fingerprint sensor 22. That is to say, the microstructure array guides the fingerprint detection light, and guides or converges the fingerprint detection light passing through the microstructure array onto the fingerprint sensor 22, so that the fingerprint sensor 22 can obtain a fingerprint image.

[0092] It should be noted that, since in this application, by using the metasurface optical element 21, it is possible to avoid the situation in the prior art where the signal amount around the perimeter is insufficient after processing and fingerprint recognition cannot be performed due to using a lens to obtain fingerprint information. Therefore, through the design of the metasurface optical element 21 in this application, on the basis of improving the light utilization rate of the fingerprint detection light, the fingerprint information obtained by the fingerprint sensor 22 can be made more stable, enabling the image processing of the fingerprint sensor 22 to have sufficient information available, thereby improving the quality of the processed fingerprint image.

[0093] Among them, the substrate 211 can be made of glass, plastic, quartz, or other optically transparent materials that can allow the fingerprint detection light to pass through, so as to minimize the loss caused by the transmission of the fingerprint detection light in the substrate 211. That is, the materials used for the substrate 211 in this embodiment include but are not limited to glass or plastic. Exemplarily, the thickness of the substrate 211 in this embodiment can be 100 μm. Considering the possibility of tolerance, the thickness of the substrate 211 can be adjusted within a certain range (such as plus or minus 5%) around 100 μm in addition to being 100 μm. The specific adjustment range depends on the thickness requirements of the fingerprint recognition module 20 and the electronic device, as well as the optical path design of the fingerprint recognition device. Or, in this embodiment, the thickness of the substrate 211 can have a certain deviation within the range allowed by the optical path design. In this embodiment, no further limitation is imposed on the above range and deviation.

[0094] In a possible implementation, referring to Figure 3 As shown, the distance between the surface of the metasurface optical element 21 facing the fingerprint sensor 22 and the fingerprint sensor 22 is 0.005 mm - 0.3 mm. That is to say, the image distance v between the metasurface optical element 21 and the fingerprint sensor 22 is 0.005 mm - 0.3 mm. For example, the distance between the surface of the metasurface optical element 21 facing the fingerprint sensor 22 and the fingerprint sensor 22 is 0.2 mm. The surface of the metasurface optical element 21 facing the display screen 10 and the outer surface of the fingerprint recognition area 15 (such as Figure 3The distance between the side of the fingerprint recognition area shown in the figure facing the finger 200 is 0.5 mm - 2 mm. Alternatively, when the finger 200 is placed on the fingerprint recognition area 15 for fingerprint recognition, the distance between the side of the metasurface optical element 21 facing the display screen 10 and the outer surface of the fingerprint recognition area 15 can also be understood as the distance between the side of the metasurface optical element 21 facing the display screen 10 and the side of the finger 200 facing the display screen 10 is 0.5 mm - 2 mm. That is to say, the object distance u between the metasurface optical element 21 and the fingerprint sensor 22 is 0.5 mm - 2 mm. For example, the distance between the side of the metasurface optical element 21 facing the display screen 10 and the finger 200 on the fingerprint recognition area 15 can be 1.5 mm. In this embodiment, the distances between the metasurface optical element 21 and the finger 200 and the fingerprint sensor 22 are 0.5 mm - 2 mm and 0.005 mm - 0.3 mm respectively. On the one hand, this meets the requirements of the optical path design and the imaging of the fingerprint sensor 22. On the other hand, without changing the overall thickness of the electronic device such as the mobile phone 100, due to the adoption of the metasurface optical element 21, the fingerprint recognition device has the characteristics of being thin, light and miniaturized, so that there is a large distance between the metasurface optical element 21 and the display screen 10, which helps to reduce the assembly process of the fingerprint recognition device.

[0095] Figure 4 FIG. is a schematic structural diagram of a microstructure array provided by an embodiment of the present application. Figure 5 FIG. is a schematic structural diagram of another microstructure array provided by an embodiment of the present application.

[0096] Reference Figure 4 and Figure 5 As shown, in this embodiment, the microstructure array may include a plurality of microstructure units 212. The distance between the centers of two adjacent microstructure units 212 is a structural period L of the metasurface optical element 21. Each microstructure unit 212 includes a plurality of microstructures 2121, and the plurality of microstructures 2121 are arranged to form a microstructure unit 212 with a preset shape. Through the microstructure unit 212, the microstructures 2121 are regularly arranged on the substrate 211. While realizing the convergence of the fingerprint detection light transmitted through the display screen 10 to the fingerprint sensor 22, by changing the arrangement mode of the microstructures 2121 on the substrate 211, the shape of the microstructure unit 212 and the distance between the centers of two adjacent microstructure units 212 are changed to meet different optical path design requirements.

[0097] Exemplarily, referring to Figure 4 shown, in this embodiment, the preset shape of the microstructure unit 212 may be a quadrilateral. Or, as Figure 5As shown, the preset shape of the microstructure unit 212 may also be a hexagon, or the preset shape of the microstructure unit 212 may be other symmetric shapes. That is, in this embodiment, the preset shape of the microstructure unit 212 includes but is not limited to a quadrilateral or a hexagon.

[0098] In this embodiment, by designing the preset shape of the microstructure unit 212 as a quadrilateral or a hexagon, on the one hand, it can make the microstructure units 212 in the microstructure array be regularly arranged on the substrate 211, so that the fingerprint detection light can be transmitted to the fingerprint sensor 22 according to the preset optical path design, thereby increasing the light intensity for fingerprint recognition and improving the fingerprint recognition effect. On the other hand, by designing the preset shape of the microstructure unit 212 as a quadrilateral or a hexagon, it can also make the structure of the microstructure unit and the microstructure array more diverse. In practical applications, by changing the preset shape of the microstructure unit 212 in the microstructure array, while achieving the convergence of the fingerprint detection light to the fingerprint sensor 22 for fingerprint recognition, different optical path design requirements of the fingerprint recognition device can be met. Therefore, in this embodiment, no further limitation is imposed on the above preset shape of the microstructure unit 212.

[0099] In this embodiment, the refractive index of the microstructure 2121 may be greater than that of the substrate 211. For example, the microstructure 2121 has a higher refractive index compared to the substrate 211, so that the microstructure 2121 and the substrate 211 have different refractive indices for the fingerprint detection light, thereby correcting the optical path of the fingerprint detection light propagating to the fingerprint sensor 22 to achieve the required effect.

[0100] In this embodiment, the material of the microstructure 2121 may be silicon, titanium dioxide, silicon nitride, gallium nitride, or other materials with a high refractive index for the fingerprint detection light. That is, in this embodiment, the material of the microstructure 2121 includes but is not limited to silicon or titanium dioxide.

[0101] Among them, in this embodiment, the microstructure 2121 may be a nanoscale microcolumn. For example, the structural dimensions (such as height and width) of the microstructure 2121 are all nanoscale, making the metasurface optical element 21 have the characteristics of being ultra-thin and miniaturized, which helps to reduce the size of the stacked structure of the fingerprint recognition device. On the basis of meeting the optical path design requirements of the optical fingerprint recognition device, it can reduce the requirements for the assembly process and space of the stacked structure, and contribute to the thinning and lightening of the electronic device.

[0102] In a possible implementation, the micro-columns may have a rotationally symmetric structure. Of course, in this embodiment, the micro-columns include, but are not limited to, a rotationally symmetric structure, and may also be a non-rotationally symmetric structure. On the one hand, the rotationally symmetric structure in this embodiment facilitates the processing of the micro-columns, thereby reducing the manufacturing difficulty and cost of the metasurface optical element 21 and the fingerprint recognition device. On the other hand, it can make the fingerprint detection light converged by the micro-columns more regular.

[0103] It should be noted that in this embodiment, the rotationally symmetric structure is a structure that coincides with the initial figure after rotating a planar figure around a fixed point on the plane by α (in radians, where 0° < α < 360°). This fixed point is called the center of rotational symmetry, and the rotation angle is called the angle of rotation.

[0104] Exemplarily, in this embodiment, the micro-columns may be cylinders, cubes, hexahedrons, or other rotationally symmetric structures. Alternatively, the micro-columns may also be non-rotationally symmetric structures, such as triangular prisms. In this way, while realizing the guidance of the fingerprint detection light, the structures of the micro-columns and the micro-structure array can be made more diverse. In this embodiment, the structure of the micro-structure 2121 is not further limited.

[0105] In order to enable the metasurface optical element 21 to have a better converging effect on the fingerprint detection light, in this embodiment, the structural period L of the metasurface optical element 21 is less than or equal to 1 / 2 of the wavelength of the fingerprint detection light. Wherein, as shown in Figure 5 The structural period L is the distance between the centers of two adjacent micro-structure units 212. When the structural period L is less than or equal to 1 / 2 of the wavelength of the fingerprint detection light, the micro-structures 2121 can be densely arranged on the substrate 211. By adjusting the structural period of the metasurface optical element 21 within the above range, the light intensity of the fingerprint detection light passing through the micro-structures 2121 can be increased, the light utilization rate of the fingerprint detection light can be improved, and thus the fingerprint recognition effect can be improved.

[0106] Figure 6 This is a schematic structural diagram of a metasurface optical element provided by an embodiment of the present application. Figure 7 This is a schematic structural diagram of a metasurface optical element provided by an embodiment of the present application. Figure 8 This is a schematic structural diagram of another metasurface optical element provided by an embodiment of the present application.

[0107] Furthermore, in this embodiment, the height of the micro-structure 2121 is greater than 1 / 2 of the wavelength of the fingerprint detection light, so as to extend the transmission path of the fingerprint detection light in the micro-structure 2121 or increase the probability of the fingerprint detection light passing through the micro-structure 2121, thereby enabling the metasurface optical element 21 to have a better converging effect on the fingerprint detection light, further improving the fingerprint recognition effect, and thus enhancing the fingerprint recognition experience of the user in a complex environment.

[0108] Exemplarily, in this embodiment, the structural period L of the metasurface optical element 21 may be 100 nm - 500 nm. For example, the structural period L of the metasurface optical element 21 may be 400 nm or 240 nm. The height h of the microstructures 2121 may be 300 nm - 500 nm. For example, the height h of the microstructures 2121 may be 470 nm or 400 nm. Specifically, in this embodiment, the structural period L of the metasurface optical element 21 and the height h of the microstructures 2121 depend on the wavelength of the fingerprint detection light. Therefore, in practical applications, corresponding adjustments can be made within the above ranges according to the wavelength of the fingerprint detection light used. In this embodiment, the structural period L of the metasurface optical element 21 and the height h of the microstructures 2121 will not be further limited.

[0109] As a possible implementation manner, referring to Figure 6 as shown, in this embodiment, a microstructural array is provided on the side of the substrate 211 facing the display screen 10. Alternatively, referring to Figure 7 as shown, a microstructural array is provided on the side of the substrate 211 facing the fingerprint sensor 22. Or, referring to Figure 8 as shown, microstructural arrays are respectively provided on the side of the substrate 211 facing the display screen 10 and the side of the substrate 211 facing the fingerprint sensor 22. For example, the substrate 211 is located between the two microstructural arrays, so that the fingerprint detection light passing through the display screen 10 is first converged by the microstructures 2121 above the substrate 211 and then passes through the substrate 211, and then is converged to the fingerprint sensor 22 by the microstructures 2121 below the substrate 211 to obtain a fingerprint image. Through the setting of the microstructural arrays on both sides of the substrate 211, the fingerprint recognition device can be applied to more complex application scenarios for fingerprint recognition, so that the fingerprint detection light applied to fingerprint recognition has a higher intensity, the fingerprint information obtained by the fingerprint sensor 22 is more stable, and the fingerprint sensor 22 has sufficient fingerprint information to utilize, thereby improving the quality of the processed fingerprint image and the effect of fingerprint recognition. Through the above three possible setting methods of the microstructural arrays, on the basis of realizing under-screen fingerprint recognition, on the one hand, there can be various setting methods for the microstructural array on the metasurface optical element 21, so that the metasurface optical element 21 and the fingerprint recognition device are diversified. On the other hand, the fingerprint recognition device can be applied to different application scenarios to improve the applicability of the fingerprint recognition device.

[0110] Exemplarily, referring to Figure 8 as shown, when microstructural arrays are provided on both sides of the substrate 211 on the metasurface optical element 21, the metasurface optical element 21 may adopt the metasurface optical element as shown in Figure 6 and the metasurface optical element as shown in Figure 7The metasurface optical elements shown in [description] are combined by being arranged one above the other. Alternatively, the metasurface optical element 21 may have a microstructure array (i.e., a double-sided metasurface optical element 21) that shares a substrate 211 on both sides, such that the microstructure array is located on one side (i.e., the upper surface) of the metasurface optical element 21 facing the display screen 10 and on the other side (i.e., the lower surface) of the metasurface optical element 21 facing the fingerprint sensor 22. At this time, the microstructure arrays on both sides of the substrate 211 may be arranged opposite to each other (i.e., as shown in Figure 8 ), or may be arranged in a staggered manner on the substrate 211 (i.e., the microstructure arrays on both sides of the substrate 211 are offset by a certain distance), as long as the transmission of the optical path is satisfied and the fingerprint detection light can be guided to the fingerprint sensor 22. In this embodiment, the formation method of the microstructure arrays on both sides of the metasurface optical element 21 is not further limited.

[0111] Specifically, in this embodiment, the metasurface optical element 21 can be understood as a metasurface lens, and this metasurface lens can be a single-sided metasurface lens, or this metasurface lens can be a double-sided metasurface lens. This can make the design of the metasurface optical element 21 more diverse and enable the fingerprint recognition device to have a wider range of applicability.

[0112] In practical applications, referring to Figure 9 , the metasurface optical element 21 can be bonded to the fingerprint sensor 22 through a bonding layer 24 or fixed in other ways. Among them, the thickness L1 of the bonding layer 24 can be 0.005 mm - 0.3 mm. That is to say, the thickness L1 of the bonding layer 24 is equal to the image distance v between the metasurface optical element 21 and the fingerprint sensor 22. In this embodiment, on the one hand, the metasurface optical element 21 can be fixed to the fingerprint sensor 22 through the bonding layer 24, and on the other hand, the requirement for the image distance v during imaging can be met by adjusting the thickness L1 of the bonding layer 24.

[0113] In order to make the fingerprint recognition device thinner and lighter, the thickness L2 of the fingerprint recognition module 20 in this embodiment is less than or equal to 1 mm. On the basis of meeting the optical path design and fingerprint imaging requirements, on the one hand, a larger distance is provided between the metasurface optical element 21 and the finger 200, which helps to reduce the assembly process of the fingerprint recognition device; on the other hand, it helps to make the fingerprint recognition device and electronic devices such as the mobile phone 100 thinner and lighter. It should be noted that for the above three possible setting methods of the microstructure array (the microstructure array is set on one side or both sides of the substrate 211), the thickness L2 of the fingerprint recognition module 20 is less than or equal to 1 mm. Specifically, the thickness L2 of the fingerprint recognition module 20 includes the thicknesses of the fingerprint sensor 22, the substrate 211, the microstructure array on one side or both sides, and the thickness L1 of the bonding layer 24, that is, the total thickness of the fingerprint sensor 22, the substrate 211, the microstructure array on one side or both sides, and the bonding layer 24 is less than or equal to 1 mm.

[0114] Among them, the thickness L3 of the metasurface optical element 21 is less than or equal to 200 μm. On the basis of realizing fingerprint recognition, compared with the fingerprint recognition device in the prior art, the fingerprint recognition device can be made into an ultra-thin form (thickness less than or equal to 1 mm). In this way, on the one hand, it helps to reduce the assembly process of the fingerprint recognition device, and on the other hand, it helps to make the electronic device such as the mobile phone 100 thinner and lighter. It should be noted that when microstructured arrays are provided on both sides of the substrate 211 or the metasurface optical element 21 is composed of two metasurface optical elements 21 combined as shown in Figure 6 and Figure 7 When the two metasurface optical elements 21 are combined, based on meeting the requirements of optical path design and imaging requirements, the height h of the microstructures 2121 and the thickness of the substrate 211 can be appropriately adjusted in practical applications so that the total thickness L3 of the metasurface optical element 21 is less than or equal to 200 μm and the thickness L2 of the fingerprint recognition module 20 is less than or equal to 1 mm.

[0115] Specifically, in this embodiment, the display screen 10 can be an OLED display screen 10a or other self-luminous display screens, or the display screen 10 can also be a liquid crystal display screen (LCD) 10b or other passive-luminous display screens. That is to say, the fingerprint recognition device of the present application is not limited to the application scenarios of the OLED display screen 10a or the liquid crystal display screen 10b, making the applicability of the fingerprint recognition device of the present application wider.

[0116] On the basis of the above, the following further elaborates on the fingerprint recognition device of the present application for different application scenarios of the OLED display screen 10a and the liquid crystal display screen 10b.

[0117] Scenario 1

[0118] Taking the application of the fingerprint recognition device of the present application to the OLED display screen 10a as an example, the application of the fingerprint recognition device of the present application to a self-luminous display screen is further introduced.

[0119] Figure 10 It is a schematic structural diagram of another electronic device equipped with a fingerprint recognition device provided by an embodiment of the present application.

[0120] Refer to Figure 10 As shown, when the fingerprint recognition device is arranged below the OLED display screen 10a, due to the self-luminous characteristic of the OLED display screen 10a, the OLED display screen 10a emits light in the direction away from the fingerprint recognition module 20 (i.e., above the OLED display screen 10a) for screen display. Since the OLED display screen 10a needs to perform screen display, the light emitted by the OLED display screen 10a for screen display is visible light.

[0121] As is well known, visible light consists of monochromatic lights with multiple different wavelength ranges. Among them, monochromatic lights include, for example, red light, orange light, yellow light, green light, cyan light, blue light, and violet light. When the visible light emitted by the OLED display screen 10a irradiates the finger 200 above the fingerprint recognition area 15, the visible light of the OLED display screen 10a is reflected by the finger 200 to form fingerprint detection light. The fingerprint detection light passing through the OLED display screen 10a is guided by the metasurface optical element 21 to the fingerprint sensor 22 to obtain fingerprint information. It can be seen from this that the fingerprint detection light formed by the finger 200 and the light emitted by the OLED display screen 10a are both visible lights.

[0122] In order to improve the recognition effect of the fingerprint sensor 22 on the fingerprint detection light, in this embodiment, when the display screen 10 is the OLED display screen 10a, the fingerprint detection light can be the monochromatic light emitted by the OLED display screen 10a. After this monochromatic light acts on the finger 200 on the fingerprint recognition area 15, fingerprint detection light for fingerprint recognition can be formed. That is to say, the monochromatic light emitted by the OLED display screen 10a can be used as the light source for fingerprint recognition. After being reflected by the finger 200, this light source can be received by the fingerprint sensor 22 for fingerprint recognition. This can avoid interference from other monochromatic lights in the visible light to the fingerprint recognition effect, so as to improve the fingerprint recognition effect.

[0123] In some examples, the monochromatic light in the OLED display screen 10a as the light source for fingerprint recognition can be green light or other monochromatic lights with wavelengths that can be received and recognized by the fingerprint sensor 22. That is, in this embodiment, the monochromatic light in the OLED display screen 10a as the light source for fingerprint recognition includes but is not limited to green light. When green light is used as the light source for fingerprint recognition, on the one hand, the wavelength range (577nm - 492nm) of green light is convenient for the fingerprint sensor 22 to perform fingerprint recognition. On the other hand, when green light is used as the light source for fingerprint recognition, it can play a role in protecting the eyes and can improve the user experience on the basis of realizing under-screen fingerprint recognition.

[0124] Figure 11 It is a schematic diagram of the split structure of the transparent protective cover plate and the display module in the display screen of the electronic device provided by the embodiment of the present application. Figure 12 It is a schematic diagram of the first setting method of the filter element provided by the embodiment of the present application. Figure 13 It is a schematic diagram of the second setting method of the filter element provided by the embodiment of the present application. Figure 14 It is a schematic diagram of the third setting method of the filter element provided by the embodiment of the present application. Figure 15 It is a schematic diagram of the fourth setting method of the filter element provided by the embodiment of the present application.

[0125] Refer to Figure 11As shown, the OLED display screen 10a may include a transparent protective cover plate 11 and a display module 12. Exemplarily, the protective cover plate 11 may be a glass cover plate or a sapphire cover plate. The display module 12 may be an OLED display module, or the display module 12 may be a liquid crystal display module. In this scenario, taking the display module 12 as an OLED display module as an example, the fingerprint recognition device of the embodiments of the present application will be further described.

[0126] Generally speaking, the display screen 10 may further include a touch panel (Touch Panel, TP). The touch panel (not marked in the figure) may be provided between the display module 12 and the protective cover plate 11 (i.e., TP on cell). Or the touch panel may be provided in the film layer of the display module 12 (i.e., TP in cell). The display module 12 is used to output display content to the user, and the touch panel is used to receive touch events input by the user on the display screen 10.

[0127] As a possible implementation manner, in order to avoid interference of other light on fingerprint recognition, in this embodiment, the fingerprint recognition module 20 further includes a light filtering element 25. The light filtering element 25 is used to filter the fingerprint detection light, so that other light in the fingerprint detection light is filtered out before reaching the fingerprint sensor 22, avoiding other light entering the fingerprint sensor 22 to interfere with fingerprint recognition, so as to reduce the signal processing difficulty. It should be noted that other light in the fingerprint detection light includes other green light or interfering light (such as red light, etc.) outside the wavelength band of the fingerprint detection light in this application scenario.

[0128] Reference Figure 12 As shown, in this embodiment, the light filtering element 25 may be located inside or on the surface of the protective cover plate 11 of the OLED display screen 10a. When the light filtering element 25 is located on the surface of the protective cover plate 11, the light filtering element 25 may be located on the side of the protective cover plate 11 close to the fingerprint recognition module 20. In this embodiment, when the fingerprint detection light passes through the OLED display screen 10a, other light in the fingerprint detection light is filtered out by the light filtering element 25 inside or on the surface of the protective cover plate 11, so as to reduce the signal processing difficulty.

[0129] Or, reference Figure 13 and Figure 14As shown, the filter element 25 may be located inside or on the surface of the metasurface optical element 21. At this time, the filter element 25 may be formed inside or on the surface of the substrate 211 of the metasurface optical element 21. When the filter element 25 is located on the surface of the metasurface optical element 21, the filter element 25 may be located on the side of the substrate 211 of the metasurface optical element 21 close to the fingerprint sensor 22. At this time, the filter element 25 may be embedded on the side of the substrate 211 close to the fingerprint sensor 22 and located between the substrate 211 and the microstructure 2121. Alternatively, the filter element 25 may also be located on the substrate 211 and between two adjacent microstructures 2121. In this embodiment, as long as other light rays in the fingerprint detection light can be filtered out by the filter element 25, it is sufficient.

[0130] Alternatively, the filter element 25 may be located on the side of the substrate 211 of the metasurface optical element 21 close to the display screen 10, such as the OLED display screen 10a (as Figure 14 shown). In this embodiment, when the fingerprint detection light passes through the metasurface optical element 21, other light rays in the fingerprint detection light are filtered out by the filter element 25 inside or on the surface of the metasurface optical element 21, so as to reduce the difficulty of signal processing.

[0131] Alternatively, referring to Figure 15 shown, the filter element 25 may also be located on the surface of the fingerprint sensor 22. That is to say, the filter element 25 may be located on the side of the fingerprint sensor 22 close to the metasurface optical element 21, or the filter element 25 may also be formed above the optical sensing array or the optical path guiding structure of the fingerprint sensor 22. In this embodiment, when the fingerprint detection light enters the optical sensing array for information processing inside the fingerprint sensor 22, other light rays in the fingerprint detection light are filtered out by the filter element 25, so as to reduce the difficulty of signal processing.

[0132] It should be noted that in this embodiment, regardless of whether the filter element 25 is provided on the protective cover plate 11, the metasurface optical element 21 or the fingerprint sensor 22, the filter element 25 needs to be provided on the optical path of the fingerprint detection light reflected by the finger 200 and transmitted to the fingerprint sensor 22, so that the filter element 25 can filter the fingerprint detection light entering the fingerprint sensor 22.

[0133] With the above-mentioned several setting methods of the filter element 25, on the one hand, other light rays in the fingerprint detection light are filtered out before reaching the fingerprint sensor 22, avoiding the interference of other light rays entering the fingerprint sensor 22 on fingerprint recognition. On the basis of reducing the difficulty of signal processing, the setting method of the filter element 25 is made more diverse, making the fingerprint recognition device more diverse; on the other hand, it helps to make the fingerprint recognition device thinner and lighter. On the basis of realizing fingerprint recognition, the requirement of the fingerprint recognition device for the internal assembly space of an electronic device such as the mobile phone 100 is reduced, thereby reducing the assembly difficulty of the fingerprint recognition device.

[0134] Specifically, in this embodiment, the filter element 25 can be a filter film layer formed by coating, film plating or other processes, that is, the formation methods of the filter film layer in this embodiment include but are not limited to coating or film plating.

[0135] Exemplarily, in this embodiment, the filter film layer can be a film layer formed by using a filter material in the prior art that allows a certain wavelength band (such as 525 nm) of the green light that forms the fingerprint detection light to pass through while blocking the wavelength band of the non-fingerprint detection light. Exemplarily, the filter material can be magnesium fluoride, silicon dioxide, aluminum oxide, silicon monoxide, titanium dioxide, titanium pentoxide, titanium dioxide, niobium oxide, tantalum pentoxide or zinc oxide. In this embodiment, no further limitation is made on the filter material.

[0136] In this application, the metasurface optical element is arranged between the fingerprint sensor and the display screen, and the fingerprint detection light passing through the display screen is guided to the fingerprint sensor through the metasurface optical element to obtain the fingerprint image of the finger, which helps to reduce the size of the stacked structure of the fingerprint recognition device, enhance the fingerprint recognition effect, and improve the fingerprint recognition experience of users in complex environments. In addition, it can also facilitate the later maintenance of the fingerprint recognition device or the repair of the display screen, and reduce the later maintenance cost of the mobile phone.

[0137] Scenario Two

[0138] On the basis of the above Scenario One, the difference from Scenario One is that in this scenario, the fingerprint recognition device is applied to the liquid crystal display (LCD) 10b as an example to further introduce the application of the fingerprint recognition device of this application to a passive light-emitting display screen.

[0139] Figure 16 It is a schematic exploded view of the transparent protection cover plate, liquid crystal panel and backlight element of the electronic device provided by the embodiment of this application.

[0140] In this scenario, the liquid crystal display 10b can include: a transparent protection cover plate 11 and a display module 12. Among them, the display module 12 is an LCD. Generally, referring to Figure 16As shown, the display module 12 may include a liquid crystal panel 121 and a backlight element 122. The backlight element 122 is disposed below the liquid crystal panel 121 and is used to provide a backlight (such as visible light) for the liquid crystal panel 121 to display an image. Among them, the fingerprint recognition device 20 is located below the backlight element 122.

[0141] Figure 17 It is a schematic diagram of the principle of another electronic device equipped with a fingerprint recognition device provided by an embodiment of the present application.

[0142] Specifically, referring to Figure 17 As shown, when the display screen 10 is a liquid crystal display screen 10b, the fingerprint recognition device may further include a detection light source 23. The detection light source 23 is located on one side of the fingerprint sensor 22, and the metasurface optical element 21 is located outside the light emitting area of the detection light source 23, so that the detection light emitted by the detection light source 23 irradiates the fingerprint recognition area 15 on the display screen 10 for fingerprint recognition. The metasurface optical element 21 is located outside the light emitting area of the detection light source 23. On the one hand, it can avoid the metasurface optical element 21 from blocking the light emitting area of the detection light source 23, enhance the light intensity of the finger 200 irradiated above the fingerprint recognition area 15, and thus improve the light utilization rate and fingerprint recognition effect; on the other hand, it makes the setting methods of the detection light source 23 and the fingerprint recognition device more diverse.

[0143] It should be noted that the detection light and the fingerprint detection light can be understood as light rays of the same wavelength emitted by the detection light source 23 or the OLED display screen 10a. Among them, the detection light can be understood as the light ray emitted by the detection light source 23 or the OLED display screen 10a that has not been reflected by the finger 200, such as the monochromatic light emitted by the OLED display screen 10a and reflected by the finger 20. The fingerprint detection light can be understood as the detection light carrying fingerprint information formed by being reflected by the finger 200.

[0144] Referring to Figure 17 As shown, the detection light source 23 can be located on one side of the fingerprint sensor 22 and fixed on the second circuit board 26 of the fingerprint sensor 22. The fingerprint sensor 22 can be fixed on the second circuit board 26 by soldering, bonding or other means and is electrically connected to the second circuit board 26. Among them, the second circuit board 26 can be electrically connected to the first circuit board 40 of the electronic device through a connector (such as a board-to-board connector, not marked in the figure), so as to supply power to the fingerprint sensor 22 and the detection light source 23, which has the advantages of strong compatibility and convenient adaptation. Or, the second circuit board 26 of the fingerprint sensor 22 can be directly electrically connected to the first circuit board 40 of the electronic device to supply power to the fingerprint sensor 22 and the detection light source 23.

[0145] It should be noted that the second circuit board 26 can be a flexible circuit board or a rigid-flex circuit board, so that the second circuit board 26 can be bent when electrically connected to the first circuit board 40. In this embodiment, the type of the second circuit board 26 is not further limited.

[0146] Alternatively, the detection light source 23 can also be located below the backlight element 122 of the liquid crystal display screen 10b, close to the fingerprint recognition module 20 or integrated inside the fingerprint recognition module 20. At this time, the detection light source 23 is still located on one side of the fingerprint sensor 22. Alternatively, in this embodiment, the detection light source 23 can also be set at other positions. In this embodiment, the position of the detection light source 23 is not further limited, as long as it is ensured that the detection light emitted by the detection light source 23 can irradiate the finger 200 above the LCD fingerprint recognition area 15, and the fingerprint detection light formed by the reflection of the finger 200 can pass through the backlight element 122 and enter the fingerprint sensor 22.

[0147] Furthermore, in order to avoid the detection light emitted by the detection light source 23 from interfering with the display effect of the LCD, in this embodiment, the detection light emitted by the detection light source 23 has a different wavelength from the display light for screen display (such as the backlight provided by the backlight element 122 in the LCD). That is to say, the detection light source 23 can specifically be a light source having a different wavelength band from the backlight provided by the backlight element 122, and it can be used to emit detection light of a specific wavelength band for the fingerprint recognition module 20 to perform under-screen optical fingerprint detection. Among them, the detection light of the specific wavelength band can be invisible light outside the visible light band, such as infrared light. In this way, on the basis of under-screen fingerprint recognition, the influence on the display effect of the image can be avoided.

[0148] Exemplarily, in this embodiment, the backlight provided by the backlight element 122 can be visible light. That is to say, the above-mentioned display light can be visible light. Specifically, in this embodiment, the detection light source 23 can be an infrared light source or other light sources whose wavelengths are outside the visible light band and can realize fingerprint recognition. That is to say, the detection light and the fingerprint detection light can be infrared light or other optical signals whose wavelengths are outside the visible light band and can realize fingerprint recognition. In this embodiment, the detection light can include but is not limited to infrared light. The display light is visible light, that is, the backlight provided by the backlight element 122 in the liquid crystal display screen 10b is visible light, so that the user cannot see or detect the above-mentioned detection light for fingerprint recognition through the liquid crystal display screen 10b. Therefore, the fingerprint recognition module 20 of the embodiment of the present application can not only realize under-screen optical fingerprint detection by using the fingerprint detection light passing through the liquid crystal display screen 10b, but also reduce the interference of the detection light emitted by the detection light source 23 on the display effect of the liquid crystal display screen 10b and avoid the influence on the display effect of the image.

[0149] Specifically, the detection light source 23 can be an infrared lamp, an infrared vertical cavity surface emitting laser (VCSEL for short), an infrared laser diode, or other infrared light sources.

[0150] Among them, in this embodiment, the detection light emitted by the detection light source 23 can be infrared light with wavelengths of 850 nm and 940 nm. By using the infrared light emitted by the detection light source 23 as the detection light, since the penetration ability of infrared light is stronger than that of visible light, the signal of the fingerprint detection light passing through each backlight film material in the backlight element 122 of the liquid crystal display screen 10b can be more effectively enhanced, improving the fingerprint recognition effect.

[0151] The difference from the filter element 25 in the above Scenario 1 is that in this scenario, the filter element 25 is used to filter other infrared light or interference light outside the band of the fingerprint detection light, so as to eliminate the interference of the above light on fingerprint recognition when it enters the fingerprint sensor 22, thereby improving the fingerprint recognition effect. In this embodiment, regardless of whether the filter element 25 is provided on the protective cover plate 11, the metasurface optical element 21, or the fingerprint sensor 22, the filter element 25 needs to be provided on the optical path of the fingerprint detection light reflected by the finger 200 and transmitted to the fingerprint sensor 22, so that the filter element 25 can filter the fingerprint detection light entering the fingerprint sensor 22. In this scenario, the setting method of the filter element 25 can refer to the description of the setting method of the filter element 25 in Scenario 1, and will not be further elaborated in this scenario.

[0152] Exemplarily, in this embodiment, the filter element 25 includes but is not limited to a filter film layer formed by coating or plating an infrared cut-off filter material. Among them, the infrared cut-off filter material can be magnesium fluoride, silicon dioxide, aluminum oxide, silicon monoxide, titanium dioxide, titanium pentoxide, titanium dioxide, niobium oxide, tantalum pentoxide, or zinc oxide. In this embodiment, the infrared cut-off filter material will not be further limited.

[0153] This application arranges the metasurface optical element between the fingerprint sensor and the display screen, and guides the fingerprint detection light transmitted through the display screen to the fingerprint sensor through the metasurface optical element to obtain the fingerprint image of the finger, which helps to reduce the size of the stacked structure of the fingerprint recognition device, enhance the fingerprint recognition effect, and improve the fingerprint recognition experience of users in complex environments; in addition, it can also facilitate the later maintenance of the fingerprint recognition device or the repair of the display screen, and reduce the later maintenance cost of the mobile phone.

[0154] In the description of the embodiments of the present application, it should be noted that unless otherwise clearly specified and defined, the terms "installed", "connected", and "coupled" should be understood in a broad sense. For example, it may be a fixed connection, or an indirect connection through an intermediate medium, or the communication inside two components or the interaction relationship between two components. For those of ordinary skill in the art, the specific meanings of the above terms in the embodiments of the present application can be understood according to specific circumstances.

[0155] In the description of the embodiments of the present application, the terms "first", "second", "third", "fourth", etc. (if any) in the specification, claims, and the above drawings are used to distinguish similar objects, and do not necessarily need to describe a specific order or sequence.

[0156] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the embodiments of the present application, and are not intended to limit them; although the present application is described with reference to the foregoing embodiments.

Claims

1. A fingerprint recognition device, characterized in that, It includes a fingerprint recognition module, and the fingerprint recognition module includes a fingerprint sensor and a metasurface optical element; the metasurface optical element is located on the light incident side of the fingerprint sensor and is used to guide fingerprint detection light to the fingerprint sensor, and the fingerprint sensor is used to obtain a fingerprint image of a finger according to the fingerprint detection light, and the fingerprint detection light is a detection light carrying fingerprint information formed by being reflected by the finger; The metasurface optical element includes a substrate and a microstructure array located on the substrate, the microstructure array includes a plurality of microstructure units, each microstructure unit includes a plurality of microstructures, and the refractive index of the microstructures is greater than the refractive index of the substrate; The structural period of the metasurface optical element is less than or equal to 1 / 2 wavelength of the fingerprint detection light, and the structural period is the distance between the centers of two adjacent microstructure units; The height of the microstructures is greater than 1 / 2 wavelength of the fingerprint detection light.

2. The fingerprint recognition device according to claim 1, characterized in that, The microstructure array is used to converge the fingerprint detection light to the fingerprint sensor.

3. The fingerprint recognition device according to claim 2, characterized in that, The plurality of microstructures are arranged to form the microstructure units of a preset shape.

4. The fingerprint recognition device according to claim 3, characterized in that, The preset shape is a quadrilateral or a hexagon.

5. The fingerprint recognition device according to any one of claims 1-4, characterized in that, The microstructures are nano-scale microcolumns.

6. The fingerprint recognition device according to claim 5, characterized in that, The microcolumns are rotationally symmetric structures.

7. The fingerprint recognition device according to claim 6, characterized in that, The microcolumns are cylinders, cubes or hexahedrons.

8. The fingerprint recognition device according to any one of claims 1-4, 6, 7, characterized in that, The structural period of the metasurface optical element is 100nm - 500nm, and the height of the microstructures is 300nm - 500nm.

9. The fingerprint recognition device according to any one of claims 1-4, 6, 7, characterized in that, The fingerprint recognition device is located on the side of the display screen of the electronic device facing the inside of the electronic device, the metasurface optical element is located between the fingerprint sensor and the display screen, the display screen has a fingerprint recognition area, and at least part of the fingerprint recognition area is located in the display area of the display screen.

10. The fingerprint recognition device according to claim 9, characterized in that, The distance between the surface of the metasurface optical element facing the fingerprint sensor and the fingerprint sensor is 0.005mm - 0.3mm, and the distance between the surface of the metasurface optical element facing the display screen and the outer surface of the fingerprint recognition area is 0.5mm - 2mm.

11. The fingerprint recognition device according to claim 10, characterized in that, The side of the substrate facing the display screen is provided with the microstructure array, or The side of the substrate facing the fingerprint sensor is provided with the microstructure array, or The side of the substrate facing the display screen and the side of the substrate facing the fingerprint sensor are respectively provided with the microstructure array.

12. The fingerprint recognition device according to claim 11, characterized in that, The metasurface optical element is a single-sided metasurface lens or a double-sided metasurface lens.

13. The fingerprint recognition device according to claim 11, characterized in that, The metasurface optical element is bonded to the fingerprint sensor through an adhesive layer, and the thickness of the adhesive layer is 0.005mm - 0.3mm.

14. The fingerprint recognition device according to any one of claims 1-4, 6, 7, 10-13, characterized in that, The thickness of the fingerprint recognition module is less than or equal to 1mm, wherein the thickness of the metasurface optical element is less than or equal to 200μm.

15. The fingerprint recognition device according to any one of claims 10-13, characterized in that, When the display screen is an OLED display screen, the fingerprint detection light is light for fingerprint recognition formed by the monochromatic light emitted by the OLED display screen passing through the finger on the fingerprint recognition area.

16. The fingerprint recognition device according to any one of claims 10-13, characterized in that, When the display screen is a liquid crystal display screen, the fingerprint recognition device further includes a detection light source located on one side of the fingerprint sensor, and the metasurface optical element is located outside the light emitting area of the detection light source, so that the detection light emitted by the detection light source irradiates the fingerprint recognition area.

17. The fingerprint recognition device according to claim 16, wherein The wavelength of the detection light is different from that of the display light for screen display.

18. The fingerprint recognition device according to claim 17, wherein The detection light source is an infrared light source, and the display light is visible light.

19. The fingerprint recognition device according to any one of claims 10 - 13, wherein The fingerprint recognition module further includes a filter element for filtering the fingerprint detection light; The filter element is located inside or on the surface of the protective cover plate of the display screen, or The filter element is located inside or on the surface of the metasurface optical element, or The filter element is located on the surface of the fingerprint sensor.

20. The fingerprint recognition device according to claim 19, wherein The filter element is a filter film layer formed by coating or plating.

21. An electronic device, wherein Comprising: A display screen, and the fingerprint recognition device according to any one of claims 1-20 above, wherein the fingerprint recognition device is located on the side of the display screen facing the inside of the electronic device.

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