Patent Publication Number: US-11663846-B2

Title: Fingerprint identification apparatus and electronic device

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of U.S. patent application Ser. No. 16/693,242, filed on Nov. 23, 2019, which is a continuation of international application No. PCT/CN2019/089123, filed on May 29, 2019. All of the aforementioned patent applications are hereby incorporated by reference in their entireties. 
    
    
     TECHNICAL FIELD 
     Embodiments of the present application relate to the electronic field, and more particularly, to a fingerprint identification apparatus and an electronic device. 
     BACKGROUND 
     An under-screen fingerprint identification solution refers to attaching an optical fingerprint identification module or an ultrasonic fingerprint identification module to a bottom of a light emitting layer of an organic light-emitting diode (OLED) screen, that is, either the optical fingerprint identification module or the ultrasonic fingerprint identification module is required to be closely adhered to the bottom of the light emitting layer. 
     However, since the OLED screen is costly and fragile, the OLED screen is easily damaged when the fingerprint identification module is directly attached to the OLED screen. In addition, since the fingerprint identification module and the OLED screen are completely adhered, if the fingerprint identification module is damaged, the OLED screen is easily damaged when the fingerprint identification module is disassembled. Moreover, an attaching process of directly attaching the fingerprint identification module to the OLED screen is also relatively complicated. 
     Due to the above problems, costs and complexity of an electronic device are greatly increased, and maintainability is low. 
     In addition, due to an excessive thickness of an existing fingerprint identification module, the market demand for ultra-thin electronic devices cannot be met. 
     SUMMARY 
     Embodiments of the present application provide a fingerprint identification apparatus and an electronic device, which could not only reduce costs and complexity of the electronic device, but also effectively reduce a thickness of the fingerprint identification apparatus. 
     In a first aspect, provided is a fingerprint identification apparatus that is applicable to an electronic device having a display screen, and includes: 
     a fingerprint sensor chip; and 
     a substrate, where an upper surface of the substrate extends downward to form a first groove, and at least a portion of the fingerprint sensor chip is disposed in the first groove and electrically connected to the substrate; 
     where the fingerprint sensor chip is disposed under the display screen through the substrate, and configured to receive a fingerprint detecting signal returned by reflection or scattering via a human finger on the display screen and detect fingerprint information of the finger based on the fingerprint detecting signal. 
     At least a portion of the fingerprint sensor chip is disposed in the first groove, which could effectively reduce a thickness of the fingerprint identification apparatus, and the fingerprint sensor chip is disposed under the display screen through the substrate, which could avoid using an attaching adhesive to fixedly connect the fingerprint sensor chip with the display screen, and then could reduce costs and complexity of an electronic device. For example, the substrate is fixed to a middle frame of the electronic device. 
     In some possible implementation manners, a size of the first groove is greater than a size of the fingerprint sensor chip such that there is a gap between a side wall of the fingerprint sensor chip and a side wall of the first groove for accommodating a gold wire, and the gold wire is used to electrically connect the fingerprint sensor chip with the substrate. 
     The gap between the side wall of the fingerprint sensor chip and the side wall of the first groove can be used not only to accommodate the gold wire, but also to accommodate protection glue of the gold wire, and then conductivity of the gold wire and performance of the fingerprint identification apparatus are ensured. 
     In some possible implementation manners, a depth of the first groove includes a thickness of a covering film of the substrate and a thickness of a conducting layer located under the covering film. 
     In some possible implementation manners, the substrate includes at least two conducting layers. 
     In some possible implementation manners, the depth of the first groove includes a thickness of a first conducting layer located under the covering film, the fingerprint sensor chip is electrically connected to a second conducting layer under an insulating layer through a conductive through hole (for example, a through hole penetrating the insulating layer under the first conducting layer), and thus the fingerprint sensor chip can be electrically connected to the substrate. 
     In some possible implementation manners, the fingerprint identification apparatus further includes: 
     a support disposed above the substrate around the fingerprint sensor chip; and 
     a first foam layer disposed above the support and provided with an opening penetrating the first foam layer, where the fingerprint sensor chip receives the fingerprint detecting signal returned by the reflection or scattering via the finger through the opening of the first foam layer. 
     In some possible implementation manners, a lower surface of the support is connected to the upper surface of the substrate by support fixing glue, and an upper surface of the support is connected to the first foam layer by a double-sided adhesive tape. 
     In some possible implementation manners, the support is a support formed of a double-sided adhesive tape for connecting the substrate with the first foam layer. 
     In some possible implementation manners, a side wall of the support that is close to the fingerprint sensor chip is aligned with a side wall of the first groove such that there is a gap between the support and the fingerprint sensor chip for accommodating a gold wire, and the gold wire is used to electrically connect the fingerprint sensor chip with the substrate. 
     The gap between the fingerprint sensor chip and the support can be used not only to accommodate the gold wire, but also to accommodate protection glue of the gold wire, and then conductivity of the gold wire and performance of the fingerprint identification apparatus are ensured. 
     In some possible implementation manners, a thickness of the support is 0.05 mm˜0.1 mm. 
     In some possible implementation manners, the fingerprint sensor chip is fixed in the first groove by fingerprint sensor chip fixing glue. 
     In some possible implementation manners, the upper surface of the substrate is provided with a gold finger of the substrate that is formed at a side of the first groove. 
     In some possible implementation manners, a first step is formed by an upper surface of the gold finger of the substrate and the upper surface of the substrate, and a thickness of the first step includes a thickness of a conducting layer of the substrate that is located under a covering layer. 
     In some possible implementation manners, the upper surface of the substrate extends downward in a first area to form a second groove, a second step is formed by the upper surface of the substrate and an upper surface of the gold finger of the substrate in a second area, the first area is an area where a side of the gold finger of the substrate is close to the first groove, and the second area is an area where a side the gold finger of the substrate is away from the first groove. 
     In some possible implementation manners, a depth of the second groove includes a thickness of a covering layer of the substrate and a thickness of a conducting layer located under the covering layer, and a thickness of the second step is the thickness of the conducting layer of the substrate that is located under the covering layer. 
     In some possible implementation manners, the fingerprint identification apparatus further includes: 
     a flexible circuit board provided with a gold finger of the flexible circuit board; and 
     an anisotropic conductive film, where the gold finger of the flexible circuit board is electrically connected to the gold finger of the substrate by the anisotropic conductive film. 
     The substrate and the flexible circuit board are electrically connected through the gold fingers, which could not only ensure insulativity between contacts, but also ensure conductivity between the substrate and the flexible circuit board. Particularly, in a case that the fingerprint sensor chip includes a plurality of chips, the plurality of chips on the substrate may be quickly electrically connected to the flexible circuit board through gold fingers, and then assembly complexity and disassembly complexity could be reduced. 
     In some possible implementation manners, the gold finger of the substrate and the gold finger of the flexible circuit board include a plurality of conductive contacts. 
     In some possible implementation manners, the plurality of conductive contacts are provided with a conductive protective layer. 
     In some possible implementation manners, a lower surface of the flexible circuit board extends upward in a third area to form a third groove, a third step is formed by the lower surface of the flexible circuit board and a lower surface of the gold finger of the flexible circuit board in a second area, the third area is an area where a side of the gold finger of the flexible circuit board is away from the first groove, and the second area is an area where a side of the gold finger of the flexible circuit board is close to the first groove. 
     In some possible implementation manners, the gold finger of the flexible circuit board is located at one end of the flexible circuit board. 
     In some possible implementation manners, the gold finger of the flexible circuit board is located at a middle position of the flexible circuit board, one end of the flexible circuit board is provided with an opening penetrating the flexible circuit board, and the opening of the flexible circuit board is aligned with an opening of the first groove such that the fingerprint sensor chip is disposed in the opening of the flexible circuit board. 
     In some possible implementation manners, a side wall of the flexible circuit board that is close to the fingerprint sensor chip is aligned with a side wall of the first groove such that there is a gap between the flexible circuit board and the fingerprint sensor chip for accommodating a gold wire, and the gold wire is used to electrically connect the fingerprint sensor chip with the substrate. 
     The gap between the flexible circuit board and the fingerprint sensor chip can be used not only to accommodate the gold wire, but also to accommodate protection glue of the gold wire, and then conductivity of the gold wire and performance of the fingerprint identification apparatus are ensured. 
     In some possible implementation manners, the substrate is a rigid circuit board portion of a rigid and flexible circuit board. 
     In some possible implementation manners, a depth of the first groove includes a thickness of a covering film of the substrate and a thickness of at least two conducting layers located under the covering film. 
     In some possible implementation manners, the fingerprint identification apparatus further includes: 
     a gold wire, where the fingerprint sensor chip is electrically connected to the substrate through the gold wire; and 
     gold wire protection glue for encapsulating the gold wire. 
     In some possible implementation manners, an arc height or an encapsulation height of the gold wire is less than 150 μm. 
     In some possible implementation manners, the fingerprint identification apparatus further includes: 
     an optical path layer disposed above the fingerprint sensor chip and configured to transmit the fingerprint detecting signal returned by the reflection or scattering via the finger to the fingerprint sensor chip. 
     In some possible implementation manners, the optical path layer includes a micro lens layer and a light blocking layer, the micro lens layer has a micro lens array formed by a plurality of micro lenses, the light blocking layer has a plurality of micro holes and is disposed under the micro lens layer, and the micro holes are in one-to-one correspondence with the micro lenses. 
     In some possible implementation manners, the optical path layer further includes a filter, and the filter is disposed above the micro lens layer or disposed in an optical path between the micro lens layer and the fingerprint sensor chip. 
     In some possible implementation manners, the fingerprint sensor chip includes a plurality of optical fingerprint sensor chips, and the plurality of optical fingerprint sensor chips are arranged side by side in the first groove to be spliced into an optical fingerprint sensor chip assembly. 
     In some possible implementation manners, the fingerprint identification apparatus further includes: 
     an image processor electrically connected to the substrate. 
     In some possible implementation manners, the fingerprint identification apparatus further includes: 
     at least one capacitor electrically connected to the substrate and configured to optimize the fingerprint detecting signal acquired by the fingerprint sensor chip. 
     In some possible implementation manners, the fingerprint identification apparatus further includes: 
     a connector electrically connected to the substrate and configured to connect an external apparatus or another component of the electronic device. 
     In some possible implementation manners, a distance between a lower surface of a light emitting layer of the display screen and an upper surface of the fingerprint sensor chip is less than 600 μm. 
     In some possible implementation manners, a thickness of the substrate ranges from 0.1 mm to 0.4 mm. 
     A second foam layer is disposed under the display screen, the second foam layer is provided with a hole penetrating the second foam layer, and the fingerprint sensor chip is disposed under the hole of the second foam layer. 
     In some possible implementation manners, a middle frame of the electronic device is provided with a fourth groove, and at least a portion of the substrate is disposed in the fourth groove. 
     In a second aspect, provided is an electronic device, including: 
     a display screen; and 
     a fingerprint identification apparatus disposed under the display screen, where the fingerprint identification apparatus is the fingerprint identification apparatus according to the first aspect or any one of possible implementation manners of the first aspect, and a fingerprint capturing area of the fingerprint identification apparatus is at least partially located in a display area of the display screen. 
     In some possible implementation manners, the electronic device further includes: 
     a second foam layer disposed under the display screen and provided with a hole penetrating the second foam layer, where the fingerprint sensor chip is disposed under the hole of the second foam layer. 
     In some possible implementation manners, the electronic device further includes: 
     a middle frame provided with a fourth groove, where at least a portion of the fingerprint identification apparatus is disposed in the fourth groove. 
     Based on the above technical solutions, the fingerprint identification apparatus and the electronic device according to the embodiments of the present application could not only reduce costs and complexity of the electronic device, but also effectively reduce a thickness of the fingerprint identification apparatus. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG.  1    is a schematic plan view of an electronic device applicable to the present application. 
         FIG.  2    is a schematic side cross-sectional view of the electronic device shown in  FIG.  1   . 
         FIG.  3    is a schematic structural view of an electronic device having a fingerprint identification module according to an embodiment of the present application. 
         FIGS.  4  to  7    are schematic structural views of a fingerprint identification module according to an embodiment of the present application. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     The technical solutions in embodiments of the present application will be described hereinafter with reference to the accompanying drawings. 
     The technical solutions of the embodiments of the present application may be applied to various electronic devices. 
     For example, portable or mobile computing devices such as smartphones, laptops, tablets and gaming devices, and other electronic devices such as electronic databases, automobiles and bank automated teller machines (ATM), which are not limited in the embodiments of the present application. 
     The technical solutions of the embodiments of the present application may be applied to a biometric identification technology. The biometric identification technology includes, but is not limited to, identification technologies, such as fingerprint identification, palm print identification, iris identification, human face identification and living body identification. For convenience of illustration, a fingerprint identification technology is described below as an example. 
     The technical solutions of the embodiments of the present application may be used for an under-screen fingerprint identification technology and an in-screen fingerprint identification technology. 
     The under-screen fingerprint identification technology refers to mounting a fingerprint identification module under a display screen, so as to realize a fingerprint identification operation in a display area of the display screen without setting a fingerprint capturing area in an area other than the display area on a front face of an electronic device. Specifically, the fingerprint identification module uses light returned from a top surface of a display component of the electronic device for fingerprint sensing and other sensing operations. This returned light carries information about an object (for example, a finger) that is in contact with or near the top surface of the display component, and the fingerprint identification module located under the display component implements under-screen fingerprint identification by acquiring and detecting this returned light. The fingerprint identification module may be designed to achieve desired optical imaging by properly configuring an optical element for acquiring and detecting a returned light, so that fingerprint information of the finger is detected. 
     Correspondingly, the in-screen (In-display) fingerprint identification technology refers to mounting a fingerprint identification module or a part of a fingerprint identification module inside a display screen, so as to realize a fingerprint identification operation in a display area of the display screen without setting a fingerprint capturing area in an area other than the display area on the front face of an electronic device. 
       FIGS.  1  and  2    are schematic views showing an electronic device  100  applicable to an under-screen fingerprint identification technology.  FIG.  1    is a schematic front view of an electronic device  100 , and  FIG.  2    is a schematic partial cross-sectional structural view of the electronic device  100  shown in  FIG.  1   . 
     As shown in  FIG.  1    and  FIG.  2   , the electronic device  100  may include a display screen  120  and a fingerprint identification module  140 . 
     The display screen  120  may be a self-emitting display screen that adopts a self-emitting display unit as a display pixel. For example, the display screen  120  may be an organic light-emitting diode (OLED) display screen or a micro light-emitting diode (micro-LED) display screen. In other alternative embodiments, the display screen  120  may also be a liquid crystal display (LCD) screen or another passive light-emitting display screen, which is not limited in the embodiments of the present application. 
     In addition, the display screen  120  may specifically be a touch display screen, which may not only display an image, but also detect a touch or press operation of a user, thereby providing the user with a human-machine interaction interface. For example, in an embodiment, the electronic device  100  may include a touch sensor, and the touch sensor may specifically be a touch panel (TP), which may be disposed on a surface of the display screen  120 , or may be partially integrated or entirely integrated into an interior of the display screen  120  to form the touch display screen. 
     The fingerprint identification module  140  may be an optical fingerprint identification module, for example, including an optical fingerprint sensor. 
     Specifically, the fingerprint identification module  140  may include a sensor chip (hereinafter also referred to as an optical fingerprint sensor) having an optical sensing array. The optical sensing array includes a plurality of optical sensing units, and each of the optical sensing units may specifically include a photo detector or a photoelectric sensor. In other words, the fingerprint identification module  140  may include a photo detector array (or referred to as a photoelectric detector array, a photoelectric sensor array) including a plurality of photo detectors distributed in an array. 
     As shown in  FIG.  1   , the fingerprint identification module  140  may be disposed in a partial area under the display screen  120  such that a fingerprint capturing area (or detecting area)  130  of the fingerprint identification module  140  is at least partially located in a display area  102  of the display screen  120 . 
     Certainly, in other alternative embodiments, the fingerprint identification module  140  may also be disposed at another position, such as a side of the display screen  120  or a non-light transmissive area of an edge of the electronic device  100 . In this case, an optical signal from at least part of the display area of the display screen  120  may be guided to the fingerprint identification module  140  by using an optical path design, so that the fingerprint capturing area  130  is actually located in the display area of the display screen  120 . 
     In some embodiments of the present application, the fingerprint identification module  140  may include only one sensor chip, and in this case, the fingerprint capturing area  130  of the fingerprint identification module  140  has a smaller area and a fixed position, therefore, when performing fingerprint inputting, a user needs to press a finger at a specific position of the fingerprint capturing area  130 , otherwise the fingerprint identification module  140  may not be able to capture a fingerprint image, thereby resulting in poor user experience. 
     In other embodiments of the present application, the fingerprint identification module  140  may specifically include a plurality of sensor chips; the plurality of sensor chips may be disposed under the display screen  120  side by side by means of splicing, and sensing areas of the plurality of sensor chips collectively form the fingerprint capturing area  130  of the fingerprint identification module  140 . That is, the fingerprint capturing area  130  of the fingerprint identification module  140  may include a plurality of sub-areas, and each sub-area corresponds to the sensing area of one of the sensor chips, so that the fingerprint capturing area  130  of the fingerprint identification module  140  may be extended to a main area of a lower half of the display screen, that is, to an area against which the finger is usually pressed, thereby achieving a blind pressing type of a fingerprint input operation. Alternatively, when the number of sensor chips is sufficient, the fingerprint detecting area  130  may further be extended to a half of the display area or even the entire display area, thereby achieving half-screen or full-screen fingerprint detection. 
     It should be understood that the specific form of the plurality of sensor chips is not limited in the embodiment of the present application. 
     For example, the plurality of sensor chips may be individually encapsulated sensor chips, or may be a plurality of dies (Die) encapsulated in a same chip capsule. 
     For another example, the plurality of sensor chips may also be fabricated and formed in different areas of a same chip by a semiconductor process. 
     As shown in  FIG.  2   , an area where the optical sensing array of the fingerprint identification module  140  is located or a light sensing range of the optical sensing array of the fingerprint identification module  140  corresponds to the fingerprint capturing area  130  of the fingerprint identification module  140 . An area of the fingerprint capturing area  130  of the fingerprint identification module  140  may be equal to or not equal to an area of the area where the optical sensing array of the fingerprint identification module  140  is located or the optical sensing range of the optical sensing array of the fingerprint identification module  140 , which is not specifically limited in the embodiment of the present application. 
     For example, by an optical path design of light collimation, the area of the fingerprint capturing area  130  of the fingerprint identification module  140  may be designed to be substantially consistent with an area of the sensing array of the fingerprint identification module  140 . 
     For another example, by an optical path design of converging light or an optical path design of reflecting light by a macro lens, the area of the fingerprint capturing area  130  of the fingerprint identification module  140  may be larger than an area of the sensing array of the fingerprint identification module  140 . 
     An optical path design of the fingerprint identification module  140  is exemplarily described below. 
     In an example that the optical path design of the fingerprint identification module  140  adopts an optical collimator having an array of through holes with a high aspect ratio, the optical collimator may specifically be a collimator layer fabricated on a semiconductor silicon wafer, which has a plurality of collimating units or micro holes, and a collimating unit may specifically be a small hole. Light in reflected light reflected back from a finger that is vertically incident to the collimating unit may pass through the collimating unit and be received by a sensor chip under the collimating unit. However, light with an excessive large incident angle is attenuated through multiple reflection inside the collimating unit, therefore, each sensor chip may basically only receive reflected light reflected back from a fingerprint pattern right above the sensor chip, which could effectively improve image resolution and then improve a fingerprint identification effect. 
     Further, when the fingerprint identification module  140  includes a plurality of sensor chips, one collimating unit may be configured for one optical sensing unit in an optical sensing array of each sensor chip, and is disposed above a corresponding optical sensing unit by means of attachment. Of course, the plurality of optical sensing units may also share one collimating unit, that is, the one collimating unit has a sufficiently large aperture to cover the plurality of optical sensing units. Since one collimating unit may correspond to the plurality of optical sensing units and a correspondence between a spatial period of the display screen  120  and a spatial period of the sensor chips is broken, even if a spatial structure of a light emitting display array of the display screen  120  and a spatial structure of the optical sensing array of the sensor chip are similar, it could be effectively avoided that the fingerprint identification module  140  uses an optical signal passing through the display screen  120  to perform fingerprint imaging to generate Moire fringes, and the fingerprint identification effect of the fingerprint identification module  140  is effectively improved. 
     In an example that the optical path design of the fingerprint identification module  140  adopts an optical path design of an optical lens, the optical lens may include an optical lens layer having one or more lens units, for example, a lens group composed of one or more aspheric lenses, for converging reflected light reflected back from a finger to the sensing array of the sensor chip under the optical lens layer, so that the sensing array may perform imaging based on the reflected light so as to obtain an fingerprint image of the finger. 
     The optical lens layer may further be provided with a pinhole or a micro hole diaphragm formed in an optical path of the lens unit. For example, one or more light shielding sheets may be provided in the optical path of the lens unit, where at least one light shielding sheet may be provided with a light-transmitting micro hole formed in an optical axis or an optical center area of the lens unit, and the light-transmitting micro hole may serve as the foregoing pinhole or micro hole diaphragm. The pinhole or micro hole diaphragm may cooperate with the optical lens layer and/or another optical film layers above the optical lens layer and expand the field of view of the fingerprint identification module  140  to improve the fingerprint imaging effect of the fingerprint identification module  140 . 
     Further, when the fingerprint identification module  140  includes a plurality of sensor chips, one optical lens may be configured for each of the sensor chips for fingerprint imaging, or one optical lens may be configured for the plurality of sensor chips to realize light convergence and fingerprint imaging. Even when one sensor chip has dual sensing arrays (Dual-Array) or multiple sensing arrays (Multi-Array), two or more optical lenses may be configured for this sensor chip to cooperate with the dual sensing arrays or the multiple sensing arrays for optical imaging, so as to reduce an imaging distance and enhance the imaging effect. 
     In an example that the optical path design of the fingerprint identification module  140  adopts an optical path design of a micro lens (Micro-Lens) layer, the micro lens layer may have a micro lens array formed by a plurality of micro lenses, which may be provided above the sensing array of the sensor chip by a semiconductor growth process or other processes, and each micro lens may correspond to one of the sensing units in the sensing array. Another optical film layer such as a dielectric layer or a passivation layer may be provided between the micro lens layer and the sensing units, and more specifically, a light blocking layer having a plurality of micro holes may also be provided between the micro lens layer and the sensing units, where a micro hole is provided between a corresponding micro lens and a corresponding sensing unit, and the light blocking layer may block optical interference between adjacent micro lenses and sensing units such that light is converged to an interior of the micro hole through the micro lens and transmitted to a sensing unit corresponding to the micro lens via the micro hole to perform optical fingerprint imaging. 
     Optionally, a filter may further be disposed above the micro lens layer or in an optical path between the micro lens layer and the sensor chip. 
     As an optional embodiment, the filter may be disposed above the micro lens layer, for example, the filter may be connected with the micro lens layer by a cushion layer, and the cushion layer may be a transparent dielectric layer and may be used to fill up a surface of the micro lens layer; or 
     the filter may be fixed above the micro lens layer by a fixing apparatus, for example, a sealant or another support member is disposed in a non-photosensitive area around the micro lens layer to support and fix the filter. 
     As an optional embodiment, the filter may further be disposed in the optical path between the micro lens layer and the sensor chip. For example, the filter may be disposed above the sensor chip, and specifically, the filter may be fixed above the sensor chip by a fixing apparatus. For example, a sealant or another support member is disposed in a non-photosensitive area of the sensor chip to support and fix the filter, and an evaporation process or a sputtering process may also be applied to coat a film on the sensor chip to form the filter, that is, the filter is integrated with the sensor chip. It can be understood that the filter may also be to coat a film on another optical film layer, which is not limited herein. 
     It should be understood that the forgoing several implementations of an optical path directing structure may be used alone or in combination, for example, a micro lens layer may be further disposed under the collimator layer or the optical lens layer. Certainly, when the collimator layer or the optical lens layer is used in combination with the micro lens layer, the specific laminated structure or optical path may require to be adjusted according to actual needs. 
     The fingerprint identification module  140  may be used for capturing fingerprint information (such as fingerprint image information) of a user. 
     In an example that the display screen  120  adopts an OLED display screen, the display screen  120  may adopt a display screen with a self-emitting display unit, for example, an organic light-emitting diode (OLED) display screen or a micro light-emitting diode (Micro-LED) display screen. The fingerprint identification module  140  may use a display unit (that is, an OLED light source) of the OLED display screen that is located in the fingerprint capturing area  130  as an excitation light source for optical fingerprint detection. 
     When a finger touches, presses or approaches (collectively referred to as pressing for convenience of description) the fingerprint capturing area  130 , the display screen  120  emits a beam of light to a finger above the fingerprint capturing area  130 , and the beam of light is reflected by a surface of the finger to form reflected light or is scattered inside the finger to form scattered light. In related patent applications, the foregoing reflected light and scattered light are collectively referred to as reflected light for convenience of description. Since a ridge and a valley of a fingerprint have different light reflecting capabilities, reflected light from the ridge of the fingerprint and the reflected light from the valley of the fingerprint have different light intensities. After passing through the display screen  120 , the reflected light is received by the sensor chip in the fingerprint identification module  140  and converted into a corresponding electrical signal, that is, a fingerprint detecting signal; and fingerprint image data may be obtained based on the fingerprint detecting signal, and fingerprint matching verification may be further performed, thereby implementing an optical fingerprint identification function at the electronic device  100 . 
     Therefore, when a user needs to perform fingerprint unlocking or other fingerprint verification on the electronic device  100 , an input operation of fingerprint characteristics can be implemented merely by pressing a finger on the fingerprint capturing area  130  in the display screen  120 . Since capturing of the fingerprint characteristics can be implemented inside the display area  102  of the display screen  120 , a front face of the electronic device  100  in the above structure does not need to specially reserve space to set a fingerprint button (such as a Home button), so that it is possible that a full screen solution can be adopted. Therefore, the display area  102  of the display screen  120  could be substantially extended to the whole front face of the electronic device  100 . 
     Certainly, in other alternative solutions, the fingerprint identification module  140  may also provide an optical signal for fingerprint detection and identification by adopting an internal light source or an external light source. In this case, the fingerprint identification module  140  can not only apply to a self-emitting display screen such as an OLED display screen, but also apply to a non-self-emitting display screen such as a liquid crystal display screen or another passive light-emitting display screen. 
     In an example of a liquid crystal display screen having a backlight module and a liquid crystal panel, in order to support under-screen fingerprint detection of the liquid crystal display screen, an optical fingerprint system of the electronic device  100  may further include an excitation light source for optical fingerprint detection. The excitation light source may specifically be an infrared light source or a light source of non-visible light at a specific wavelength, which may be disposed under the backlight module of the liquid crystal display screen or disposed in an edge area under a protective cover of the electronic device  100 . The fingerprint identification module  140  may be disposed under the liquid crystal panel or the edge area of the protective cover, and by being directed over an optical path, light for fingerprint detection may reach the fingerprint identification module  140 . Alternatively, the fingerprint identification module  140  may also be disposed under the backlight module, and the backlight module allows the light for fingerprint detection to pass through the liquid crystal panel and the backlight module and reach the fingerprint identification module  140  by providing a hole on film layers such as a diffusion sheet, a brightening sheet, a reflection sheet or the like, or by performing other optical designs. When the fingerprint identification module  140  provides an optical signal for fingerprint detection by adopting an internal light source or an external light source, a detection principle may be the same. 
     As shown in  FIG.  1   , the electronic device  100  may further include a protective cover  110 . 
     The cover  110  may specifically be a transparent cover such as a glass cover or a sapphire cover which is located on the display screen  120  and covers a front face of the electronic device  100 , and a surface of the cover  110  may also be provided with a protective layer. Therefore, in an embodiment of the present application, the so-called finger being pressed against the display screen  120  may actually refer to the finger being pressed against the cover  110  on the display screen  120  or a surface of the protective layer covering the cover  110 . 
     As shown in  FIG.  1   , a circuit board  150  such as a flexible circuit board (Flexible Printed Circuit, FPC) may also be disposed under the fingerprint identification module  140 . 
     The fingerprint identification module  140  may be soldered to the circuit board  150  through a pad, and achieve electrical interconnection and signal transmission with other peripheral circuits or other elements of the electronic device  100  through the circuit board  150 . For example, the fingerprint identification module  140  may receive a control signal from a processing unit of the electronic device  100  through the circuit board  150 , and may also output the fingerprint detecting signal from the fingerprint identification module  140  to the processing unit, a control unit or the like of the electronic device  100  through the circuit board  150 . 
       FIG.  3    is a schematic structural view of an electronic device having a fingerprint identification apparatus according to an embodiment of the present application. 
     As shown in  FIG.  3   , an electronic device  200  may include a display screen  210 , a second foam layer  220 , a fingerprint identification apparatus  230 , a middle frame  240 , battery fixing glue  250 , and a battery  260 . The display screen  210  may be the display screen shown in  FIG.  1    and  FIG.  2   . For related description, reference may be made to the foregoing description of the display screen  120 . The fingerprint identification apparatus  230  may be the fingerprint identification module shown in  FIG.  1    and  FIG.  2   . For related functions, reference may be made to the foregoing related description of the fingerprint identification module  140 , and no further details are provided herein. It should be understood that, in other alternative embodiments, the display screen  210  and the second foam layer  220  may also be collectively referred to as a display screen, and the display screen  210  may also be referred to as a light emitting layer of the display screen, which is not specifically limited in this embodiment of the present application. 
     With reference to  FIG.  3   , an upper surface of the middle frame  240  extends downward to form a fourth groove, that is, the middle frame  240  is provided with a fourth groove, and at least a portion of the fingerprint identification apparatus  230  is disposed in the fourth groove. Further, the second foam layer  220  may be provided with an opening penetrating the second foam layer  220 , and at least a portion of the fingerprint identification apparatus  230  is disposed in the opening of the second foam layer  220 . For example, a lower surface of the fingerprint identification apparatus  230  may be attached to a lower surface of the display screen  210 . For another example, an upper surface of the fingerprint identification apparatus  230  may be attached to a bottom of the groove of the middle frame  240 . For another example, an upper surface and a lower surface of the fingerprint identification apparatus  230  may be respectively attached to a lower surface of the display screen  210  and a bottom of the groove of the middle frame  240 . 
     However, since the display screen  210  is costly and fragile, the display screen  210  is easily damaged when the fingerprint identification module  230  is directly attached to the display screen  210 . In addition, since the fingerprint identification module  230  and the display screen  210  are completely adhered, if the fingerprint identification module  230  is damaged, the display screen  210  is easily damaged when the fingerprint identification module  230  is disassembled. Moreover, an attaching process of directly attaching the fingerprint identification module  230  to the display screen  210  is also relatively complicated. Due to the above problems, costs and complexity of the electronic device  200  are greatly increased, and maintainability is low. 
     The present application provides a fingerprint identification apparatus, which could reduce the costs and the complexity of the electronic device  200  and improve the maintainability. 
     Hereinafter, the fingerprint identification apparatus  230  according to the embodiment of the present application will be described in detail with reference to  FIGS.  4  to  7   . 
     It should be noted that, for convenience of description, in the embodiments of the present application, same reference numerals are used to represent same components, and detailed description of the same components is omitted in different embodiments for the sake of brevity. 
     With reference to  FIG.  4   , the fingerprint identification apparatus  230  may include a fingerprint sensor chip  233  and a substrate  231 , an upper surface of the substrate  231  extends downward to form a first groove  2311 , and at least a portion of the fingerprint sensor chip  233  is disposed in the first groove  2311  and electrically connected to the substrate  231 . For example, a lower surface of the fingerprint sensor chip  233  is fixedly connected to a bottom of the first groove  2311  and electrically connected to the substrate  231  through a gold wire  235 . The fingerprint sensor chip  233  is disposed under the display screen  210  through the substrate  231 , and configured to receive a fingerprint detecting signal returned by reflection or scattering via a human finger on the display screen  210  and detect fingerprint information of the finger based on the fingerprint detecting signal. 
     By disposing at least a portion of the fingerprint sensor chip  233  in the first groove  2311 , a thickness of the fingerprint identification apparatus  230  could be effectively reduced; and the fingerprint sensor chip  233  is disposed under the display screen  210  through the substrate  231 , which could avoid using an attaching adhesive to fixedly connect the fingerprint sensor chip  233  with the display screen  210 , and then could reduce the costs and the complexity of the electronic device  200 . For example, the substrate  231  is fixed to the middle frame  240  of the electronic device. 
     In some embodiments, the fingerprint sensor chip  233  may include a plurality of chips or may include one chip. For example, the fingerprint sensor chip  233  may include a plurality of optical fingerprint sensor chips, and the plurality of optical fingerprint sensor chips are arranged side by side in the first groove to be spliced into an optical fingerprint sensor chip assembly. The optical fingerprint sensor chip assembly may be configured to acquire a plurality of fingerprint images simultaneously, and the plurality of fingerprint images may be used as a fingerprint image for fingerprint identification after being spliced. With reference to  FIG.  4   , the fingerprint sensor chip  233  may be a sensor chip (hereinafter also referred to as an optical fingerprint sensor) having an optical sensing array  2331 . The optical sensing array  2331  may include a plurality of optical sensing units, and each of the optical sensing units may specifically include a photo detector or a photoelectric sensor. In other words, the fingerprint sensor chip  233  may include a photo detector array (or referred to as a photoelectric detector array, a photoelectric sensor array) including a plurality of photo detectors distributed in an array. 
     With reference to  FIG.  4   , a size of the first groove  2311  may be greater than a size of the fingerprint sensor chip  233  such that there is a gap between a side wall of the fingerprint sensor chip  233  and a side wall of the first groove  2311  for accommodating the gold wire  235 , and the gold wire  235  is used to electrically connect the fingerprint sensor chip  233  with the substrate  231 . In addition, the size of the first groove  2311  is greater than the size of the fingerprint sensor chip  233 , which could reduce assembly complexity and disassembly complexity of the fingerprint sensor chip  233 . 
     A depth of the first groove  2311  may include a thickness of a covering film of the substrate  231  and a thickness of a conducting layer located under the covering film. The covering film of the substrate  231  may be an insulating layer for protecting and insulating the conducting layer under the covering film. The conducting layer located under the covering film is a circuit layer or a wiring layer of the substrate  231 , and the fingerprint sensor chip  233  may achieve an electrical connection with an external device through the circuit layer or the wiring layer of the substrate. 
     For example, the substrate  231  may include at least two conducting layers. In this case, the depth of the first groove  2311  includes a thickness of a first conducting layer located under the covering film of the substrate  231 , the fingerprint sensor chip  233  may be electrically connected to a second conducting layer under an insulating layer through a conductive through hole (for example, a through hole penetrating the insulating layer under the first conducting layer), and thus the fingerprint sensor chip  233  can be electrically connected to the substrate  231 . 
     With reference to  FIG.  4   , the fingerprint sensor chip  233  may be fixed in the first groove  2311  by fixing glue  232  for the fingerprint sensor chip  233 . 
     It should be understood that the fingerprint sensor chip  233  may also be fixedly connected to a side wall of the first groove  2311 , or may be fixed in the first groove  2311  by another means. For example, the fingerprint sensor chip  233  may be fixed in the first groove  2311  by a buckle or a screw, which is not specifically limited in this embodiment. 
     With reference to  FIG.  4   , a lower surface of the substrate  231  may further be provided with a double-sided adhesive tape  2313  so as to bond the substrate  231  to a bottom of the groove of the middle frame  240  of the electronic device  200 . 
     It should be understood that the substrate  231  may also be fixedly connected to a side wall of the groove of the middle frame  240 , or the substrate  231  may be fixedly disposed in the groove of the middle frame  240  by another means (such as a buckle or a screw), which is not specifically limited in this embodiment of the present application. 
     With reference to  FIG.  4   , the upper surface of the substrate  231  may be provided with a gold finger  2312  of the substrate  231  formed at a side of the first groove  2311 . In other words, the upper surface of the substrate  231  may be provided with a convex structure of the conducting layer of the substrate  231  formed at a side of the first groove  2311  to form the gold finger  2312  of the substrate  231 . 
     It should be understood that the specific structure of the gold finger  2312  of the substrate  231  is not specifically limited in the present application. As an example, as shown in  FIG.  4   , the upper surface of the substrate  231  extends downward in a first area to form a second groove, a second step is formed by the upper surface of the substrate  231  and an upper surface of the gold finger of the substrate  231  in a second area, the first area is an area where a side of the gold finger of the substrate  231  is close to the first groove  2311 , and the second area is an area where a side the gold finger of the substrate  231  is away from the first groove  2311 . Further, a depth of the second groove may include a thickness of a covering layer of the substrate  231  and a thickness of a conducting layer located under the covering layer, and a thickness of the second step is the thickness of the conducting layer of the substrate  231  that is located under the covering layer such that a portion of the conducting layer of the substrate  231  forms a convex structure with a convex surface facing upward, and then the gold finger  2312  of the substrate  231  is formed. 
     With reference to  FIG.  4   , the fingerprint identification apparatus  230  may further include a flexible circuit board  239  and an anisotropic conductive film  241 . The flexible circuit board  239  is provided with a gold finger  2391  of the flexible circuit board  239 ; and the gold finger  2391  of the flexible circuit board  239  is electrically connected to the gold finger  2312  of the substrate  231  by the anisotropic conductive film  241 . 
     For example, the gold finger  2391  of the flexible circuit board  239  may be located at one end of the flexible circuit board  239 . That is, one end of the flexible circuit board  239  may be electrically connected to one end of the substrate  231  by compressing the anisotropic conductive film  241 . 
     The substrate  231  and the flexible circuit board  239  are electrically connected through the gold fingers, which could not only ensure insulativity between contacts, but also ensure conductivity between the substrate  231  and the flexible circuit board  239 . Particularly, in a case that the fingerprint sensor chip  233  includes a plurality of chips, the plurality of chips on the substrate  231  may be quickly electrically connected to the flexible circuit board  239  through gold fingers, and then assembly complexity and disassembly complexity could be reduced. 
     It should be understood that the specific structure of the gold finger  2391  of the flexible circuit board  239  is not specifically limited in the present application. As an example, as shown in  FIG.  4   , a lower surface of the flexible circuit board  239  may extend upward in a third area to form a third groove, a third step may be formed by the lower surface of the flexible circuit board  239  and a lower surface of the gold finger of the flexible circuit board  239  in a fourth area, the third area is an area where a side of the gold finger  2391  of the flexible circuit board  239  is away from the first groove  2311 , and the fourth area is an area where a side of the gold finger  2391  of the flexible circuit board  239  is close to the first groove  2311 . 
     With reference to  FIG.  4   , the fingerprint identification apparatus  230  may further include protection glue  238  for the anisotropic conductive film  241 , the protection glue  238  may be provided at both ends of the anisotropic conductive film  241  to protect the anisotropic conductive film  241 , and further protect the gold finger  2312  of the substrate  231  and the gold finger  2391  of the flexible circuit board  239 . 
     With reference to  FIG.  4   , the fingerprint identification apparatus  230  may further include a support  236  and a first foam layer  245 , the first foam layer  245  is disposed above the support  236  and provided with an opening penetrating the first foam layer  245 , and the fingerprint sensor chip  233  may receive the fingerprint detecting signal returned by the reflection or scattering via the finger through the opening of the first foam layer  245 . 
     In combination with  FIG.  3   , the first foam layer  245  may be a foam layer of the fingerprint identification apparatus  230 , or may be a foam layer of the electronic device  200  that is located between the display screen  210  and the middle frame  240 , which is not specifically limited in the present application. In other words, when the first foam layer  245  is a foam layer of the fingerprint identification apparatus  230 , the first foam layer  245  may be in direct contact with the display screen  210 , and further the first foam layer  245  may be in a state of compression; and when the first foam layer  245  is a foam layer of the electronic device  200  that is located between the display screen  210  and the middle frame  240 , it is illustrated that the fingerprint identification apparatus  230  is directly attached to a lower surface of the second foam layer  220  under the display screen  210 . 
     It should be understood that the support  236  may be formed of any material that can be used to fixedly connect the substrate  231  with the first foam layer  245 . For example, the support  236  may be a support formed of a double-sided adhesive tape. 
     With reference to  FIG.  4   , a side wall of the support  236  that is close to the fingerprint sensor chip  233  may be aligned with a side wall of the first groove  2311  such that there is a gap between the support  236  and the fingerprint sensor chip  233  for accommodating the gold wire  235 . 
     The gap between the support  236  and the fingerprint sensor chip  233  can be used not only to accommodate the gold wire  235 , but also to accommodate protection glue  237  for the gold wire, and then conductivity of the gold wire  235  and performance of the fingerprint identification apparatus  230  are ensured. Moreover, the substrate  231  may also be fixed under the display screen  210  by the flexible circuit board  239  such that the fingerprint sensor chip  233  is fixed under the display screen  210 . 
     With reference to  FIG.  4   , the fingerprint identification apparatus may further include gold wire protection glue  237  for encapsulating and protecting the gold wire  235 . Optionally, an arc height or an encapsulation height of the gold wire  235  is less than a certain threshold. For example, the arc height or the encapsulation height of the gold wire is less than 150 μm. For example, the arc height or the encapsulation height of the gold wire may be more specifically less than 70 μm. 
     It should be noted that space for accommodating the gold wire  235  may also be used to accommodate the gold wire protection glue  237 . 
     For example, as shown in  FIG.  4   , space for accommodating the gold wire protection glue  237  includes, but is not limited to, the gap formed between a side wall of the fingerprint sensor chip  233  and a side wall of the first groove  2311 , the gap formed between the fingerprint sensor chip  233  and the support  236 , and a gap formed between the fingerprint sensor chip  233  and the first foam layer  245 . 
     With reference to  FIG.  4   , the fingerprint identification apparatus  230  may further include an optical path layer  234 , and the optical path layer  234  is configured to transmit the fingerprint detecting signal returned by the reflection or scattering via the finger to the fingerprint sensor chip  233 . The optical path layer  234  is disposed above the fingerprint sensor chip  233  and may be configured to achieve an optical path design, the optical path design of the fingerprint identification apparatus  230  may refer to the foregoing optical path design of the fingerprint identification module  140 , and no further details are provided herein. Only the optical path design adopting a micro lens layer is selected as an exemplary description. As an optional embodiment, the optical path layer  234  includes a micro lens layer and a light blocking layer, the micro lens layer may have a micro lens array formed by a plurality of micro lenses, the light blocking layer has a plurality of micro holes and is disposed under the micro lens layer, the micro holes are in one-to-one correspondence with the micro lenses, and the optical sensing units of the optical sensing array  2331  are in one-to-one correspondence with the micro lenses. Optionally, the optical path layer may further include another optical film layer. Specifically, another optical film layer may be provided between the micro lens layer and the fingerprint sensor chip  233 , for example, a dielectric layer or a passivation layer. Optionally, the optical path layer  234  may further include a filter, and the filter is disposed above the micro lens layer or disposed in an optical path between the micro lens layer and the sensor chip  233 . Reference may be made to the foregoing content for details, and no further details are provided herein. 
     In the embodiment of the present application, the filter is used to reduce undesired ambient light in fingerprint sensing to improve optical sensing of received light by the fingerprint sensor chip  233 . The filter may be specifically used to reject light at a specific wavelength, such as near infrared light and partial of red light. For example, human fingers absorb most of energy of light at a wavelength below 580 nm, if one or more optical filters or optical filtering layers are designed to reject light at a wavelength from 580 nm to infrared, undesired contributions to the optical detection in fingerprint sensing from the ambient light may be greatly reduced. 
     For example, the filter may include one or more optical filters, the one or more optical filters can be configured, for example, as bandpass filters to allow transmission of light emitted by an OLED screen while blocking other light components such as infrared light in the sunlight. This optical filtering could be effective in reducing background light caused by the sunlight when the under-screen fingerprint identification apparatus  230  is used outdoors. The one or more optical filters can be implemented as, for example, optical filter coatings formed on one or more continuous interfaces or may be implemented on one or more discrete interfaces. It should be understood that the filter may be fabricated on a surface of any optical film layer of the optical path layer  234  or in an optical path along reflected light formed by reflection via a finger to the fingerprint sensor chip  233 , which is not specifically limited in this embodiment of the present application. 
     In addition, a light incident face of the filter may be provided with an optical inorganic coating film or an organic blackening coating such that reflectance of the light incident face of the filter is lower than a first threshold, for example, 1%, thereby ensuring that the fingerprint sensor chip  233  can receive sufficient light signals so as to improve a fingerprint identification effect. 
     In an example that the filter is fixed to an upper surface of the fingerprint sensor chip  233  by a fixing apparatus, the filter and the fingerprint sensor chip  233  may be fixed by means of dispensing in a non-photosensitive area of the fingerprint sensor chip  233 , and there is a gap between the filter and a photosensitive area of the fingerprint sensor chip  233 . Alternatively, a lower surface of the filter is fixed on the upper surface of the fingerprint sensor chip  233  by glue having a refractive index lower than a preset refractive index. For example, the preset refractive index includes, but is not limited to, 1.3. 
     It should be noted that when the filter is attached to the upper surface of the fingerprint sensor chip  233  by filling of an optical adhesive, if the thickness of the adhesive covering the upper surface of the fingerprint sensor chip  233  is uneven, the Newton ring phenomenon may occur, thereby affecting the fingerprint identification effect. 
     In comparison with the implementation manner in which the filter is fixed above the upper surface of the fingerprint sensor chip  233  by a fixing apparatus, when the filter is a coating film on the fingerprint sensor chip  233  or another optical film layer, a filter adopting a base material of blue glass or white glass is avoided, which may not only avoid the Newton ring phenomenon and improve the fingerprint identification effect, but also effectively reduce a thickness of the fingerprint identification apparatus  230 . 
     With reference to  FIG.  4   , the fingerprint identification apparatus may further include an image processor  244 , and the image processor  244  is electrically connected to the substrate  231 . For example, the image processor is disposed above the flexible circuit board  239  and electrically connected to the substrate  231  through the flexible circuit board  239 . For example, the image processor  244  may be a microprocessor (Microprogrammed Control Unit, MCU) for receiving a fingerprint detecting signal (for example, a fingerprint image) transmitted from the fingerprint sensor chip  233  through the flexible circuit board  239  and simply processing the fingerprint detecting signal. 
     With reference to  FIG.  4   , the fingerprint identification apparatus may further include at least one capacitor  243 , and the at least one capacitor  243  is electrically connected to the substrate  231  and configured to optimize the fingerprint detecting signal acquired by the fingerprint sensor chip  233 . For example, the at least one capacitor  243  is disposed on the flexible circuit board  239  and electrically connected to the substrate  231  through the flexible circuit board  239 , then electrically connected to the fingerprint sensor chip  233 , and the at least one capacitor  243  may be configured to optimize the fingerprint detecting signal acquired by the fingerprint sensor chip  233 . For example, the at least one capacitor  243  is configured to perform filtering processing on the fingerprint detecting signal acquired by the fingerprint sensor chip  233 . The fingerprint sensor chip  233  may correspond to one or more capacitors. For example, each chip in the fingerprint sensor chip  233  corresponds to one or more capacitors. 
     With reference to  FIG.  4   , the fingerprint identification apparatus may further include a connector  242 , and the connector  242  is electrically connected to the substrate  231 . For example, the connector  242  may be electrically connected to the substrate  231  through the flexible circuit board  239 . The connector  242  may be configured to connect an external apparatus or another component of the electronic device so as to realize communication with the external apparatus or another component of the electronic device. For example, the connector  242  may be configured to connect a processor of the electronic device so that the processor of the electronic device receives a fingerprint detecting signal processed by the image processor  244  and performs fingerprint identification based on the processed fingerprint detecting signal. 
     It should be understood that  FIG.  4    is only an example of the present application and may not be understood as limitation to the present application 
     For example, in some alternative embodiments, the fingerprint sensor chip  233  may be provided with a through silicon via (TSV) and/or a redistribution layer (RDL), and the TSV and/or RDL is used to guide pins of the fingerprint sensor chip  233  from the upper surface to the lower surface. The lower surface of the fingerprint sensor chip  233  may be provided with a wiring layer through the TSV and/or RDL. The wiring layer of the lower surface of the fingerprint sensor chip  233  may be electrically connected to a wiring layer in the first groove  2311  of the substrate  231  through the gold wire  235 . In this case, an outer wall of the fingerprint sensor chip  233  may be attached to a side wall of the first groove  2311 , and a gap for accommodating the gold wire  235  may be provided between the lower surface of the fingerprint sensor chip  233  and the bottom of the first groove  2311 . Further, the fingerprint sensor chip  233  may be further provided with a protective layer on a surface of the wiring layer for protecting and insulating the fingerprint sensor chip  233 . 
     It should be understood that the support  236  may be a support formed of a material having adhesive properties. For example, the support  236  may be a support formed of a double-sided adhesive tape, but the embodiment of the present application is not limited thereto. For example, the support  236  may also be a support formed of a material having no adhesive property. For example, the material of the support  236  includes, but is not limited to, metal, resin, a fiberglass composite plate or the like, and in this case, the support  236  needs to be fixed between the foam layer  245  and the substrate  231 . 
       FIG.  5    is a deformation structure of the fingerprint identification apparatus shown in  FIG.  4   . 
     With reference to  FIG.  5   , the support  236  may be used as an independent component, that is, in addition to the support  236 , the fingerprint identification  230  may include a double-sided adhesive tape  247  and support fixing glue  246 , where a lower surface of the support  236  is connected to the upper surface of the substrate  231  by the support fixing glue  246 , and an upper surface of the support  236  is connected to the first foam layer  245  by the double-sided adhesive tape  247 . As an optional embodiment, the support  236  and the support fixing glue  246  may also be a one-piece structure, and the one-piece structure serves as a support. For example, the support may be a support formed of a single-sided adhesive tape for connecting the substrate  231 , and an upper surface of the support is connected to the first foam layer  245  by the double-sided adhesive tape  247 . 
     It should be understood that the gold finger  2391  of the flexible circuit board  239  may be located at one end of the flexible circuit board  239 , but the embodiment of the present application is not limited thereto. For example, the gold finger  2391  of the flexible circuit board  239  is located at a middle position of the flexible circuit board  239 , or the gold finger  2391  of the flexible circuit board  239  is close to a middle position of the flexible circuit board  239 . 
       FIG.  6    is another deformation structure of the fingerprint identification apparatus shown in  FIG.  4   . 
     With reference to  FIG.  6   , the gold finger of the flexible circuit board  239  is located at a middle position of the flexible circuit board  239 , one end of the flexible circuit board  239  is provided with an opening penetrating the flexible circuit board  239 , and the opening of the flexible circuit board  239  is aligned with an opening of the first groove  2311  such that the fingerprint sensor chip  233  is disposed in the opening of the flexible circuit board  239 . In other words, an opening is provided between one end  2392  of the flexible circuit board  239  and the gold finger  2391  of the flexible circuit board  239 , and the opening of the flexible circuit board  239  is aligned with the opening of the first groove  2311  such that the fingerprint sensor chip  233  is disposed in the opening of the flexible circuit board  239 . 
     In this case, in an area around the fingerprint sensor chip  233 , the flexible circuit board  239  may be fixed above the substrate  231  by the anisotropic conductive film  241 . 
     With reference to  FIG.  6   , a side wall of the flexible circuit board that is close to the fingerprint sensor chip  233  is aligned with a side wall of the first groove  2311  such that there is a gap between the flexible circuit board  239  and the fingerprint sensor chip  233  for accommodating a gold wire  235 , and the gold wire  235  is used to electrically connect the fingerprint sensor chip  233  with the substrate  231 . 
     The gap between the flexible circuit board  239  and the fingerprint sensor chip  233  can be used not only to accommodate the gold wire  235 , but also to accommodate protection glue  237  for the gold wire, and then conductivity of the gold wire  235  and performance of the fingerprint identification apparatus  230  are ensured. 
     It should be understood that the substrate  231  and the flexible circuit board  239  may respectively have gold fingers such that the substrate  231  is electrically connected to the flexible circuit board  239  by means of compressing an anisotropic conductive film (ACF), but the embodiment of the present application is not limited thereto. For example, the substrate  231  and the flexible circuit board  239  may be integrally disposed, that is, the substrate  231  and the flexible circuit board  239  may serve as only two parts of one component. 
       FIG.  7    is yet another deformation structure of the fingerprint identification apparatus shown in  FIG.  4   . 
     With reference to  FIG.  7   , the substrate  231  and the flexible circuit board  239  may serve as a rigid circuit board portion and a flexible circuit board portion of a rigid and flexible circuit board, that is, the first groove  2311  is disposed at the rigid circuit board portion of the rigid and flexible circuit board. In this case, an upper surface of the rigid circuit board portion may be fixedly connected to a lower surface of the first foam layer  245  by the support  236  (for example, a support formed of a double-sided adhesive tape). 
     It should be understood that  FIGS.  4  to  7    are only examples of the present application and may not be understood as limitation to the present application 
     For example, the preferred embodiments of the present application are described in detail above with reference to the accompanying drawings. However, the present application is not limited to specific details in the foregoing embodiments. Within the technical concept of the present application, a variety of simple variants may be carried out on the technical solution of the present application, and all of the simple variants are within the protection scope of the present application. For example, various specific technical features described in the foregoing specific embodiments may be combined in any suitable manner under the condition of no contradiction. In order to avoid unnecessary repetition, various possible combination ways will not be separately described in the present application. For another example, any combination may be made between various embodiments of the present application without departing from the idea of the present application, and it should also be regarded as the disclosure of the present application. 
     For example, the fingerprint identification apparatuses shown in  FIG.  5    and  FIG.  7    may be partially used in combination. For example, the flexible circuit board  239  and the substrate  231  in  FIG.  5    may be replaced with the rigid and flexible circuit board of  FIG.  7   . 
     The present application further provides an electronic device, which includes a display screen and the fingerprint identification apparatus referred to above, the fingerprint identification apparatus is disposed under the display screen, and a fingerprint capturing area of fingerprint identification apparatus is at least partially located in a display area of the display screen. 
     With reference to  FIG.  3   , the electronic device  200  may include a middle frame  240 . The middle frame  240  is used to support the display screen of the electronic device. An upper surface of the middle frame  240  extends downward to form a fourth groove, that is, the middle frame  240  is provided with a fourth groove, and the groove of the middle frame  240  is used to accommodate the fingerprint identification apparatus  230 . 
     Further, the electronic device may further include a second foam layer  220 . The second foam layer  220  is disposed under the display screen  210 , the second foam layer  220  is provided with an opening window, the fingerprint identification apparatus  230  receives an optical signal emitted by the display screen  210  that is formed after being reflected via a human finger, and the optical signal is used for fingerprint identification. 
     There is a gap between a fingerprint sensor chip  233  in the fingerprint identification apparatus  230  and a lower surface of the display screen  210  (for example, a gap of the second foam layer  220 ). The gap may be an air gap that is not filled with any auxiliary material, which can ensure that the fingerprint sensor chip  233  will not be in contact with the lower surface of the display screen when the display screen is pressed or the electronic device is dropped or collided, and stability and performance of fingerprint identification for the fingerprint sensor chip  233  are not affected. 
     The display screen  210  may be an OLED organic light-emitting panel made using a low temperature poly-silicon (LTPS) technology, the display screen  210  is ultra-thin in thickness, light in weight and low in power consumption and may be used to provide clearer images. 
     The second foam layer  220  may also be used as a screen print layer or an embossed layer, the screen print layer may be provided with patterns and texts, and the patterns and texts may be used as a logo such as a trademark pattern. The second foam layer  220  may be a black sheet-like layer or a print layer for shielding light. In other embodiments, the second foam layer  220  may also be referred to as a cushion layer, a rear panel, or a heat dissipation layer. 
     In an example that the display screen is an OLED screen, the display screen may be a soft screen or a hard screen. When a finger is placed on a bright OLED screen, the finger will reflect light emitted from the OLED screen, and the reflected light will penetrate through the OLED screen until reaching an area under the OLED screen. An optical path layer located under the OLED screen can be used to filter out an infrared signal component in leaking light. Since a fingerprint is a diffuse reflector, an optical signal formed by reflection or diffusion via a finger may exist in all directions. Further, a micro lens array that may be disposed under the OLED screen and between the OLED screen and the fingerprint sensor chip can acquire an optical signal leaking from the OLED screen. Therefore, the fingerprint sensor chip  233  performs imaging of a fingerprint image by receiving an optical signal in which red light is filtered out. 
     It should be noted that the optical signal leaking from the OLED screen includes a fingerprint signal and an internal structure signal of the screen, and the in-screen structural signal may affect the imaging of the fingerprint image. For example, Moire fringes are generated when the imaging the fingerprint image is performed. In this embodiment, by controlling a thickness of a foam layer  220  and a thickness of each part, a distance between the fingerprint sensor chip  233  and the OLED screen (for example, the lower surface of the display screen  210 ) may be within a certain threshold (for example, 600 μm) such that the imaging of the screen structure is blurred, but the imaging of the structure of the fingerprint is not affected. The shorter the distance between the fingerprint sensor chip  233  and the OLED screen is, the better the fingerprint identification performance is; therefore, under a premise of permission of reliability and process capability, the distance between the fingerprint sensor chip  233  and the OLED screen may be shorten as far as possible. 
     It should be appreciated that specific examples in embodiments of the present application are just for helping those skilled in the art better understand the embodiments of the present application, rather than for limiting the scope of the present application. 
     It should also be appreciated that terms used in the embodiments of the present application and the claims appended hereto are merely for the purpose of describing particular embodiments, and are not intended to limit the embodiments of the present application. For example, the use of a singular form of “a”, “the” and “said” in the embodiments of the present application and the claims appended hereto are also intended to include a plural form, unless otherwise clearly indicated herein by context. 
     Those of ordinary skill in the art may be aware that, elements of the examples described in the embodiments disclosed in the present application may be implemented by electronic hardware, computer software, or a combination of the two. To clearly illustrate interchangeability between the hardware and the software, the foregoing illustration has generally described composition and steps of the examples according to functions. Whether these functions are executed in hardware or software mode depends on a particular application and a design constraint condition of the technical solutions. A person skilled in the art may use different methods to implement the described functions for each particular application, but it should not be considered that the implementation goes beyond the scope of the present application. 
     In the several embodiments provided in the present application, it should be understood that, the disclosed system and apparatus may be implemented in other manners. For example, the described apparatus embodiment is merely an example. For example, the described apparatus embodiment is merely an example. For example, the element division is merely logical function division and may be other division in actual implementation. For example, a plurality of elements or components may be combined or integrated into another system, or some features may be ignored or not performed. In addition, the displayed or discussed mutual coupling or direct coupling or communication connection may be indirect coupling or communication connection through some interfaces, apparatuses or elements, and may also be electrical, mechanical, or connection in other forms. 
     The various functional elements referred to above may be integrally disposed, or each element may exist alone physically. The various functional elements may be implemented in a form of hardware, or may be implemented in a form of a software functional unit. If the integrated unit is implemented in the form of the software functional unit and is sold or used as an independent product, it may be stored in a computer readable storage medium. Based on such understanding, the nature of the technical solutions of the present application, or the part contributing to the prior art, or all of or part of the technical solutions may be implemented in a form of a software product. The computer software product is stored in a storage medium and includes several instructions for instructing a computer device (which may be a personal computer, a server, or a network device, and the like) to execute all of or part of the steps of the method described in the embodiments of the present application. The storage medium includes: various media that may store program codes, such as a U-disk, a removable hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk, a compact disk, and so on. 
     The foregoing descriptions are merely specific embodiments of the present disclosure. The protection scope of the present application, however, is not limited thereto. Any person who is skilled and familiar with the present technical field may readily conceive of various equivalent modifications or substitutions within the technical scope disclosed in the present application, and all of these modifications or substitutions shall fall within the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.