CN111164609B

CN111164609B - Fingerprint identification device and electronic equipment

Info

Publication number: CN111164609B
Application number: CN201980004258.XA
Authority: CN
Inventors: 高攀; 吴宝全; 刘辰锦
Original assignee: Shenzhen Goodix Technology Co Ltd
Current assignee: Shenzhen Goodix Technology Co Ltd
Priority date: 2019-06-14
Filing date: 2019-09-24
Publication date: 2023-10-13
Anticipated expiration: 2039-09-24
Also published as: CN111164609A

Abstract

A fingerprint recognition device and an electronic apparatus are provided, which can reduce the thickness of the fingerprint recognition device without affecting the performance of a fingerprint recognition chip. The fingerprint identification device is used for being arranged below a display screen of electronic equipment to realize fingerprint identification, and comprises: the optical fingerprint chip is used for receiving the fingerprint optical signal returned by the reflection or scattering of the finger and converting the fingerprint optical signal into a fingerprint electric signal; the optical filter is arranged above the optical fingerprint chip, the lower surface of the optical filter is directly provided with a metal circuit layer, and the metal circuit layer is connected with the optical fingerprint chip through a solder ball and is used for transmitting fingerprint electric signals of the optical fingerprint chip.

Description

Fingerprint identification device and electronic equipment

The present application claims priority from international office, application number PCT/CN2019/091412, international application entitled "optical fingerprint device and electronic device", filed on 6/14 of 2019, the entire contents of which are incorporated herein by reference.

Technical Field

The present application relates to the field of optical fingerprint technology, and more particularly, to a fingerprint identification apparatus and an electronic device.

Background

With the advent of the mobile phone full screen age, the application of the off-screen fingerprint identification device is more and more widespread, and the off-screen optical fingerprint identification device is most popular. In an under-screen optical fingerprint recognition device, a screen is used as a light source, light signals are emitted to a finger, and fingerprint recognition is performed based on the light signals by collecting the light signals reflected by the finger. In this process, a filter layer is generally required to filter out interference light such as ambient light, so as to improve fingerprint recognition performance. In some embodiments, the filter layer is externally arranged above the fingerprint identification chip in the under-screen fingerprint identification device and is fixed through the adhesive layer or the bracket, but in this way, the thickness of the under-screen fingerprint identification device is increased. In order to reduce the thickness of the under-screen fingerprint recognition device, in another embodiment, the filter layer is built in the fingerprint recognition chip of the under-screen fingerprint recognition device, but in this way, the fingerprint recognition chip is easy to warp, and the performance and reliability of the fingerprint recognition chip are affected.

Therefore, how to reduce the thickness of the fingerprint recognition device without affecting the performance of the fingerprint recognition chip is a problem to be solved urgently.

Disclosure of Invention

The embodiment of the application provides a fingerprint identification device and electronic equipment, which can reduce the thickness of the fingerprint identification device on the basis of not affecting the performance of a fingerprint identification chip.

In a first aspect, a fingerprint identification apparatus is provided, configured to be disposed below a display screen of an electronic device to implement fingerprint identification, including:

the optical fingerprint chip is used for receiving the fingerprint optical signal returned by the reflection or scattering of the finger and converting the fingerprint optical signal into a fingerprint electric signal;

the optical filter is arranged above the optical fingerprint chip, the lower surface of the optical filter is directly provided with a metal circuit layer, and the metal circuit layer is connected with the optical fingerprint chip through a solder ball and is used for transmitting fingerprint electric signals of the optical fingerprint chip.

According to the fingerprint identification device, the metal circuit layer is arranged on the optical filter and is connected with the optical fingerprint chip through the solder balls, so that the thickness of the fingerprint identification device is reduced, the optical fingerprint chip is not warped, the identification performance of the fingerprint identification device is not affected, the light and thin development of the fingerprint identification device is facilitated, and the fingerprint identification device can be applied to more scenes.

In one possible implementation, the metal wiring layer is used to form a fan-out wafer level package of the optical fingerprint chip.

In the embodiment of the application, the number and the spacing of the bonding pads of the optical fingerprint chip are not limited by the area of the optical fingerprint chip by a fan-out type wafer level packaging mode. And the optical filters are integrated when the optical fingerprint chip with multiple pins is packaged at the wafer level, so that the performance of the optical fingerprint chip in multiple aspects can be improved.

In one possible implementation, the material of the metal line layer comprises aluminum; and/or the thickness of the metal circuit layer is 100nm to 3000nm.

In one possible implementation manner, the material of the metal circuit layer is aluminum-copper alloy, wherein the mass fraction of copper in the aluminum-copper alloy is less than 5%;

or the material of the metal circuit layer is aluminum-gold alloy, wherein the mass fraction of gold in the aluminum-gold alloy is less than 5%;

or the material of the metal circuit layer is aluminum silver alloy, wherein the mass fraction of silver in the aluminum silver alloy is less than 5%.

In the embodiment of the application, the metal circuit layer is made of aluminum material, so that the process cost of the fingerprint identification device can be reduced, and the adhesion between the metal circuit layer and the optical filter can be increased by directly growing the metal circuit layer made of aluminum material on the optical filter.

In one possible implementation, the metal circuit layer is a patterned circuit layer directly formed on the lower surface of the optical filter by adopting a physical vapor deposition method, and is subjected to a photoetching and etching process or a photoetching and stripping process treatment.

In one possible implementation manner, a first protective adhesive layer is disposed on a surface of the metal circuit layer, and the metal circuit layer forms a bonding pad through the first protective adhesive layer, and the bonding pad is formed in an edge area of the optical filter.

In one possible implementation, the pad surface is grown with bumps through which the solder balls are connected to the pad.

In one possible implementation, the bump is a gold bump.

In the embodiment of the application, the gold bumps are adopted to realize the connection between the bonding pads, so that the complexity of the process of the fingerprint identification device can be reduced, and the process yield can be improved.

In one possible implementation, the material of the first protective adhesive layer is an inorganic material, where the inorganic material is: one or more of silicon oxide, silicon nitride, silicon oxynitride; and/or the number of the groups of groups,

the thickness of the first protective adhesive layer is 100nm to 3000nm.

In one possible implementation manner, the first protective adhesive layer is a pattern layer formed by plating a film on the surface of the metal circuit layer by adopting a chemical vapor deposition method and performing photoetching and etching processes or photoetching and stripping processes.

In one possible implementation manner, the metal circuit layer and the first protective adhesive layer are hollowed out in the middle area, and the optical fingerprint chip is arranged below the hollowed-out area to receive a fingerprint light signal from a finger above the display screen, wherein the fingerprint light signal is used for detecting fingerprint information of the finger.

In one possible implementation, the area of the hollowed-out area is larger than the sensing area of the optical fingerprint chip.

In one possible implementation manner, the optical filter includes a transparent substrate, and the upper surface and the lower surface of the transparent substrate are respectively provided with a filter layer, where the filter layer is used for transmitting the optical signal of the target band and filtering the optical signal of the non-target band.

In one possible implementation, the filter layer on the upper surface of the transparent substrate is between 10 layers and 80 layers, and the coating layer on the lower surface of the transparent substrate is between 10 layers and 80 layers.

In one possible implementation, the transparent substrate is an alkali or alkali-free glass having a thickness of 0.1 to 0.7mm.

In the embodiment of the application, the transparent substrate is made of a material with certain strength and is used for providing support for the optical fingerprint chip connected with the transparent substrate, and the warpage of the optical filter can be controlled by coating the upper and lower surfaces of the transparent substrate, so that the performance of the fingerprint identification device is improved.

In one possible implementation, the target band is the visible band.

In one possible implementation, the metal line layer is formed with a first pad and a second pad, and the first pad is connected with a pad on the optical fingerprint chip through the solder ball;

the bonding pad on the optical fingerprint chip is used for transmitting the fingerprint electric signal to the first bonding pad, and the first bonding pad is used for transmitting the fingerprint electric signal to the second bonding pad.

In one possible implementation, the second pad is used to transmit the fingerprint electrical signal to a flexible circuit board, which is disposed under the optical filter.

In one possible implementation, the fingerprint recognition device further includes: the second bonding pad is connected with the bonding pad on the flexible circuit board through the solder ball connection.

In the embodiment of the application, the flexible circuit board can play a role in reinforcement and support through the optical filter, so that the reinforcing plate can not be arranged below the flexible circuit board, the overall thickness of the fingerprint identification device can be effectively reduced, and the requirements of lightening and thinning of electronic equipment can be met.

In one possible implementation, the flexible circuit board is disposed at the periphery of the optical fingerprint chip.

In one possible implementation, the middle region of the flexible circuit board is hollowed out, and the optical fingerprint chip is disposed in the hollowed out region.

In the embodiment of the application, the optical fingerprint chip is arranged in the hollowed-out area of the flexible circuit board, so that the overall thickness of the fingerprint identification device can be further reduced.

In one possible implementation, the flexible circuit board is disposed outside an edge region of the optical fingerprint chip.

In one possible implementation, the pad of the optical fingerprint chip is disposed at an edge region of the optical fingerprint chip, and the pad of the flexible circuit board is disposed at an edge region of the flexible circuit board and near one side of the optical fingerprint chip.

In one possible implementation, the fingerprint recognition device further includes:

and the second protective adhesive layer is used for coating the first bonding pad, the second bonding pad, the bonding pad on the optical fingerprint chip and the bonding pad on the flexible circuit board.

and the optical component is arranged between the optical filter and the optical fingerprint chip and is used for guiding or converging fingerprint light signals from above the display screen to the optical fingerprint chip.

In one possible implementation, the optical component includes at least one light blocking layer and a microlens array, the at least one light blocking layer is located below the microlens array, and a plurality of light-passing apertures are provided, and the optical fingerprint chip is configured to receive optical signals converged to and passing through the plurality of light-passing apertures via the microlens array.

and the retaining wall structure is arranged between the second protective adhesive layer and the optical assembly and is used for isolating the optical assembly from the second protective adhesive layer.

In one possible implementation, the retaining wall structure is disposed on an upper surface of the optical fingerprint chip or a lower surface of the first protective adhesive layer.

In one possible implementation manner, if the retaining wall structure is disposed on the upper surface of the optical fingerprint chip, the height of the upper surface of the retaining wall structure is lower than the lower surface of the first protective adhesive layer; or alternatively

If the retaining wall structure is arranged on the lower surface of the first protective adhesive layer, the height of the lower surface of the retaining wall structure is higher than that of the upper surface of the optical fingerprint chip.

In one possible implementation, the display screen is an OLED display screen, and the optical fingerprint chip uses a portion of the display unit of the OLED display screen as an excitation light source for optical fingerprint detection.

In a second aspect, an electronic device is provided, comprising a display screen and a fingerprint recognition device as in the first aspect or any possible implementation of the first aspect, wherein the fingerprint recognition device is arranged below the display screen.

In a possible implementation, the display screen is an organic light emitting diode OLED display screen, the display screen comprising a plurality of OLED light sources, wherein the fingerprint recognition device employs at least part of the OLED light sources as excitation light sources for optical fingerprint detection.

The electronic device according to the embodiment of the present application, which adopts the foregoing first aspect or any one of the possible implementation manners of the first aspect, can save an internal space of the electronic device and even reduce an overall thickness of the electronic device.

Drawings

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

Fig. 2 is a schematic structural view of a typical fingerprint recognition device.

Fig. 3 is a schematic block diagram of another typical fingerprint recognition device.

Fig. 4 is a schematic structural view of a fingerprint recognition device according to an embodiment of the present application.

Fig. 5a is a schematic structural diagram of an optical filter and a lower surface film layer thereof according to an embodiment of the present application.

Fig. 5b is a schematic structural diagram of another optical filter and a lower surface film layer thereof according to an embodiment of the present application.

Fig. 6 is a schematic structural diagram of a filter and an optical fingerprint chip connected by bumps and solder balls according to an embodiment of the present application.

Fig. 7 is a schematic structural view of a specific fingerprint recognition device according to an embodiment of the present application.

Fig. 8 is a schematic structural view of another specific fingerprint recognition device according to an embodiment of the present application.

Fig. 9 is a schematic structural view of another specific fingerprint recognition device according to an embodiment of the present application.

Fig. 10 is a schematic block diagram of an electronic device of an embodiment of the present application.

Detailed Description

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

It should be understood that the embodiments of the present application may be applied to optical fingerprint systems, including but not limited to optical fingerprint identification systems and products based on optical fingerprint imaging, and the embodiments of the present application are only described by way of example in terms of optical fingerprint systems, but should not be construed as limiting the embodiments of the present application in any way, and the embodiments of the present application are equally applicable to other systems employing optical imaging techniques, etc.

As a common application scenario, the optical fingerprint system provided by the embodiment of the application can be applied to smart phones, tablet computers and other mobile terminals or other electronic devices with display screens; more specifically, in the above electronic device, the fingerprint recognition device may be specifically an optical fingerprint device, which may be disposed in a partial area or an entire area Under the display screen, thereby forming an Under-screen (Under-display) optical fingerprint system. Alternatively, the fingerprint recognition device may be partially or fully integrated inside a display screen of the electronic apparatus, thereby forming an In-screen (In-display) optical fingerprint system.

Referring to fig. 1, a schematic structural diagram of an electronic device to which an embodiment of the present application may be applied is shown, where the electronic device 10 includes a display screen 120 and an optical fingerprint device 130, and the optical fingerprint device 130 is disposed in a partial area under the display screen 120. The optical fingerprint device 130 includes an optical fingerprint sensor, which includes a sensing array 133 having a plurality of optical sensing units 131, where the sensing array 133 is located or the sensing area thereof is the fingerprint detection area 103 of the optical fingerprint device 130. As shown in fig. 1, the fingerprint detection area 103 is located in the display area of the display screen 120. In an alternative embodiment, the optical fingerprint device 130 may also be disposed at other locations, such as the side of the display screen 120 or an edge non-transparent area of the electronic device 10, and the optical signals of at least a portion of the display area of the display screen 120 are directed to the optical fingerprint device 130 by an optical path design such that the fingerprint detection area 103 is actually located in the display area of the display screen 120.

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

Therefore, when the user needs to unlock the electronic device or perform other fingerprint verification, the user only needs to press the finger against the fingerprint detection area 103 located on the display screen 120, so as to realize fingerprint input. Since fingerprint detection can be implemented in the screen, the electronic device 10 adopting the above structure does not need to have a special reserved space on the front surface to set fingerprint keys (such as Home keys), so that a comprehensive screen scheme can be adopted, that is, the display area of the display screen 120 can be basically expanded to the front surface of the whole electronic device 10.

As an alternative implementation manner, as shown in fig. 1, the optical fingerprint device 130 includes a light detecting portion 134 and an optical component 132, where the light detecting portion 134 includes an sensing array, and a reading circuit and other auxiliary circuits electrically connected to the sensing array, which may be fabricated on a chip (Die) such as an optical imaging chip or an optical fingerprint sensor by a semiconductor process, and the sensing array is specifically a Photo detector (Photo detector) array, which includes a plurality of Photo detectors distributed in an array, and the Photo detectors may be used as the optical sensing units as described above; the optical assembly 132 may be disposed over the sensing array of the light detection portion 134, which may include, among other optical elements, a light guiding layer or light path guiding structure that is primarily used to guide reflected light reflected from the finger surface to the sensing array for optical detection.

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

The light guiding layer or the light path guiding structure of the optical component 132 may have various implementations, for example, the light guiding layer may be a Collimator (Collimator) layer made of a semiconductor silicon wafer, which has a plurality of collimating units or a micropore array, the collimating units may be small holes, the light vertically incident to the collimating units from the reflected light reflected by the finger may pass through and be received by the optical sensing units below the collimating units, and the light with an excessive incident angle is attenuated by multiple reflections inside the collimating units, so each optical sensing unit basically only receives the reflected light reflected by the fingerprint lines above the optical sensing units, and the sensing array can detect the fingerprint image of the finger.

In another embodiment, the light guiding layer or light path guiding structure may also be an optical Lens (Lens) layer having one or more Lens units, such as a Lens group of one or more aspheric lenses, for converging the reflected light reflected from the finger to a sensing array of light detecting portions 134 thereunder so that the sensing array may image based on the reflected light, thereby obtaining a fingerprint image of the finger. Optionally, the optical lens layer may further form a pinhole in the optical path of the lens unit, and the pinhole may cooperate with the optical lens layer to expand the field of view of the optical fingerprint device to improve the fingerprint imaging effect of the optical fingerprint device 130.

In other embodiments, the light guiding layer or the light path guiding structure may also specifically employ a Micro-Lens layer having a Micro-Lens array formed of a plurality of Micro-lenses, which may be formed over the sensing array of the light sensing part 134 by a semiconductor growth process or other processes, and each Micro-Lens may correspond to one of sensing cells of the sensing array, respectively. And, other optical film layers, such as a dielectric layer or a passivation layer, may be further formed between the microlens layer and the sensing unit, and more particularly, a light blocking layer having micro holes formed between its corresponding microlens and sensing unit, which may block optical interference between adjacent microlenses and sensing unit, and allow light corresponding to the sensing unit to be converged into the inside of the micro holes by the microlenses and transmitted to the sensing unit through the micro holes for optical fingerprint imaging. It should be appreciated that several implementations of the above-described light path guiding structure may be used alone or in combination, for example, a microlens layer may be further provided under the collimator layer or the optical lens layer. Of course, when a collimator layer or an optical lens layer is used in combination with a microlens layer, the specific laminated structure or optical path thereof may need to be adjusted as actually needed.

As an alternative embodiment, the display screen 120 may employ a display screen having a self-luminous display unit, such as an Organic Light-Emitting Diode (OLED) display screen or a Micro-LED (Micro-LED) display screen. Taking an OLED display as an example, the optical fingerprint device 130 may utilize a display unit (i.e., an OLED light source) of the OLED display 120 located in the fingerprint detection area 103 as an excitation light source for optical fingerprint detection. When the finger 140 is pressed against the fingerprint detection area 103, the display 120 emits a light 111 to the target finger 140 above the fingerprint detection area 103, and the light 111 is reflected on the surface of the finger 140 to form reflected light or scattered light scattered inside the finger 140 to form scattered light, and in the related patent application, the reflected light and the scattered light are collectively referred to as reflected light for convenience of description. Since ridges (ribs) of the fingerprint and the ribs (valley) have different light reflection capacities, the reflected light 151 from the ridges of the fingerprint and the reflected light 152 from the ribs of the fingerprint have different light intensities, and the reflected light is received by the sensing array 134 in the optical fingerprint device 130 and converted into corresponding electrical signals, i.e., fingerprint detection signals after passing through the optical component 132; fingerprint image data can be obtained based on the fingerprint detection signal, and fingerprint matching verification can be further performed, thereby realizing an optical fingerprint recognition function in the electronic device 10.

In other embodiments, the optical fingerprint device 130 may also employ an internal light source or an external light source to provide an optical signal for fingerprint detection. In this case, the optical fingerprint device 130 may be adapted to a non-self-luminous display screen, such as a liquid crystal display screen or other passive light emitting display screen. Taking the application to a liquid crystal display having a backlight module and a liquid crystal panel as an example, to support the under-screen fingerprint detection of the liquid crystal display, the optical fingerprint system of the electronic device 10 may further include an excitation light source for optical fingerprint detection, which may be specifically an infrared light source or a light source of non-visible light with a specific wavelength, which may be disposed under the backlight module of the liquid crystal display or under an edge region of a protective cover plate of the electronic device 10, and the optical fingerprint device 130 may be disposed under the liquid crystal panel or the edge region of the protective cover plate and guided through an optical path so that fingerprint detection light may reach the optical fingerprint device 130; alternatively, the optical fingerprint device 130 may be disposed under the backlight module, and the backlight module may be provided with holes or other optical designs on the film layers such as the diffusion sheet, the brightness enhancement sheet, and the reflection sheet to allow the fingerprint detection light to pass through the liquid crystal panel and the backlight module and reach the optical fingerprint device 130. When the optical fingerprint device 130 employs an internal light source or an external light source to provide an optical signal for fingerprint detection, the detection principle is consistent with that described above.

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

It should also be appreciated that the electronic device 10 may also include a circuit board 150 disposed below the optical fingerprint assembly 130. The optical fingerprint device 130 may be adhered to the circuit board 150 by a back adhesive, and electrically connected to the circuit board 150 by soldering with pads and wires. The optical fingerprint apparatus 130 may enable electrical interconnection and signal transmission with other peripheral circuits or other elements of the electronic device 10 through the circuit board 150. For example, the optical fingerprint device 130 may receive a control signal of the processing unit of the electronic apparatus 10 through the circuit board 150, and may also output a fingerprint detection signal from the optical fingerprint device 130 to the processing unit or the control unit of the electronic apparatus 10 or the like through the circuit board 150.

On the other hand, in some embodiments, the optical fingerprint device 130 may include only one optical fingerprint sensor, where the area of the fingerprint detection area 103 of the optical fingerprint device 130 is small and the position is fixed, so the user needs to press the finger to a specific position of the fingerprint detection area 103 when inputting the fingerprint, otherwise, the optical fingerprint device 130 may not be able to acquire the fingerprint image, resulting in poor user experience. In other alternative embodiments, the optical fingerprint device 130 may specifically include a plurality of optical fingerprint sensors; the plurality of optical fingerprint sensors may be disposed side by side below the display screen 120 in a spliced manner, and sensing areas of the plurality of optical fingerprint sensors together form the fingerprint detection area 103 of the optical fingerprint device 130. That is, the fingerprint detection area 103 of the optical fingerprint device 130 may include a plurality of sub-areas, each corresponding to a sensing area of one of the optical fingerprint sensors, so that the fingerprint acquisition area 103 of the optical fingerprint device 130 may be extended to a main area of the lower half of the display screen, that is, to a finger usual pressing area, thereby implementing a blind press type fingerprint input operation. Alternatively, when the number of optical fingerprint sensors is sufficient, the fingerprint detection area 103 may also be extended to half or even the whole display area, thereby achieving half-screen or full-screen fingerprint detection.

It should also be understood that in embodiments of the present application, the sensing array in the optical fingerprint device may also be referred to as a pixel array, and the optical sensing unit or sensing units in the sensing array may also be referred to as pixel units.

It should be noted that, the optical fingerprint device in the embodiment of the present application may also be referred to as an optical fingerprint recognition module, a fingerprint recognition device, a fingerprint recognition module, a fingerprint acquisition device, etc., where the above terms may be replaced with each other.

Fig. 2 shows a schematic block diagram of a fingerprint recognition device 200.

As shown in fig. 2, the fingerprint recognition device 200 may include an optical component 210, an optical fingerprint chip 220, a circuit board 230, and a filter layer 240.

Wherein the optical component 210 may include a microlens array and at least one light blocking layer. It should be understood that the optical component 210 may also be any form of the optical component 132 in fig. 1, which is not limited in this embodiment of the present application.

The optical fingerprint chip 220 may be an implementation of the optical detection section 134 of fig. 1, and includes a sensing array 221, which may be the same as the sensing array 133 of fig. 1, for converting received optical signals reflected by a finger into electrical signals.

The circuit board 230 may be identical to the circuit board 150 in fig. 1. Optionally, the circuit board 230 is a flexible circuit board (Flexible Printed Circuit, FPC) disposed below the optical fingerprint chip 220, and a reinforcing plate is disposed below the flexible circuit board to fixedly support the optical fingerprint chip 220. In addition, the circuit board 230 is electrically connected to the optical fingerprint chip 220 through pads and electrical connection means. Typically, the circuit board 230 is electrically connected to the optical fingerprint chip 220 using Wire Bonding (WB) packaging. In general, the arc height of the gold wire is about 50 μm in the wire bonding method, and the gold wire needs to be protected by an encapsulation method, so that the thickness space occupied by the gold wire is large, which becomes a factor restricting the thickness of the fingerprint identification apparatus 200.

As shown in fig. 2, a filter layer 240 is disposed over the optical assembly 210, and the filter layer 240 may be a filter, and disposed over the microlens array by a connection device 250. Specifically, a transparent dielectric layer is grown over the microlens array, and then the optical filter is connected through the connection device 250. The connection means 250 may be a glue layer or the like for fixedly connecting the filter layer 240 over the microlens array. The optical filter is used for filtering optical signals interfering with fingerprint identification, such as infrared light or near infrared light in the environment.

In the embodiment of the application, the optical filter 240 needs to be connected and arranged above the optical component 210 through the adhesive layer and the transparent dielectric layer, and the thickness of the optical filter 240 is large and the effect of the wire bonding packaging mode is affected, so that the overall thickness of the fingerprint identification device 200 is large, which is not beneficial to the development of the thinning of the fingerprint identification device and the application of more scenes.

To reduce the overall thickness of the fingerprint recognition device, in one possible embodiment, a filter layer 240 is provided on the surface of the optical fingerprint chip 220, and fig. 3 shows a schematic structural diagram of the fingerprint recognition device 200 in this embodiment.

As shown in fig. 3, the filter layer 240 may be grown directly over the sensing array 221 in the optical fingerprint chip 220. Optionally, the filter layer 240 may be integrated with the sensing array 221 in an optical fingerprint chip. Specifically, the filter layer 240 may be formed by directly coating a film on the sensor array 221 using an evaporation process, for example, a multi-layer filter film may be prepared above the sensor array 221 by atomic layer deposition, sputter coating, electron beam evaporation coating, ion beam coating, or the like.

Since the optical fingerprint chip 220 and the sensing array 221 therein are generally manufactured by using silicon (Si) as a substrate, a filter layer is directly formed thereon by vapor deposition, and the silicon substrate is easily warped during the growth process, in other words, the optical fingerprint chip 220 is warped, thereby affecting the performance and reliability of the optical fingerprint chip and further affecting the identification performance of the fingerprint identification device 200.

In addition, in the embodiment of the present application, a reinforcing plate needs to be disposed under the circuit board to fixedly support the optical fingerprint chip 220, and the thickness of the reinforcing plate also increases the thickness of the fingerprint recognition device 200, which is disadvantageous for the development of the light and thin fingerprint recognition device 200.

The application provides a fingerprint identification device, which adopts a novel packaging mode, reduces the thickness of the fingerprint identification device, does not cause the warpage of an optical fingerprint chip, can improve the identification performance of the fingerprint identification device, is beneficial to the development of the thinning of the fingerprint identification device, and is applied to more scenes.

Hereinafter, referring to fig. 4 to 9, a fingerprint recognition device according to an embodiment of the present application will be described in detail.

In the embodiments shown below, the same reference numerals are used for the same structures for the sake of understanding, and detailed description of the same structures is omitted for the sake of brevity.

Fig. 4 is a schematic structural diagram of a fingerprint recognition device 300 according to an embodiment of the present application, where the fingerprint recognition device 300 is configured to be disposed under a display screen, so as to implement fingerprint recognition.

As shown in fig. 4, the fingerprint recognition device 300 includes:

an optical fingerprint chip 320 for receiving the fingerprint optical signal returned by the reflection or scattering of the finger and converting the fingerprint optical signal into a fingerprint electrical signal;

The optical filter 330 is disposed above the optical fingerprint chip 320, a metal circuit layer 340 is formed on the lower surface of the optical filter 330, and the metal circuit layer 340 is connected to the optical fingerprint chip 320 through solder balls 360 and is used for transmitting fingerprint electric signals of the optical fingerprint chip 320.

Specifically, the optical fingerprint chip 320 is configured to receive the fingerprint optical signal and form a fingerprint electrical signal, and the optical fingerprint chip 320 may include a plurality of optical sensing units to form a sensing array 321, and the sensing array 321 may be identical to the sensing array 133 in fig. 1. Optionally, the plurality of optical sensing units are configured to receive the fingerprint optical signal, process the fingerprint optical signal to obtain a fingerprint image electrical signal, and the fingerprint image electrical signal obtained by processing by one optical sensing unit is a unit pixel in the fingerprint image.

Alternatively, the optical sensing unit may be square or rectangular. Alternatively, the optical sensing unit may be a Photodiode (PD), a metal oxide semiconductor field effect transistor (Metal Oxide Semiconductor Field Effect Transistor, MOSFET), or the like. The optical sensing unit has high light sensitivity and high quantum efficiency for light with specific wavelength, so as to detect light signals with corresponding wavelength reflected or scattered by fingers.

Specifically, the optical filter 330 is an optical wavelength cut-off filter, and is configured to transmit an optical signal of a target band, filter an optical signal of a non-target band, and reduce an influence of an ambient optical signal of the non-target band, so as to improve fingerprint recognition performance.

Preferably, the target band is a visible light band, for example, a band range of 350nm to 650 nm.

Alternatively, the target band may be a band range of 350 to 700 nm.

Alternatively, the target band may be a band range of 800 to 1000 nm.

Alternatively, the target band may be a band range of 350 to 700nm and a band range of 800 to 1000 nm.

Optionally, the optical filter 330 has a transmittance of the optical signal of the target band greater than a first threshold, for example, 90%, and a transmittance of the optical signal of the non-target band less than a second threshold, for example, 10%.

As shown in fig. 4, the lower surface of the optical filter 330 is directly grown with a metal line layer 340, a first pad 341 and a second pad 342 are formed on the metal line layer 340, a chip pad 322 is disposed on the optical fingerprint chip 320, and a metal solder ball 360 connects the first pad 341 and the chip pad 322, thereby connecting the optical fingerprint chip 320 and the optical filter 330. Meanwhile, the fingerprint electrical signal on the optical fingerprint chip 320 may also be transmitted to the first pad 341 through the metal solder ball 360, and after the first pad 341 receives the fingerprint electrical signal, the fingerprint electrical signal is transmitted to the second pad 342 through the metal circuit layer 340, and the fingerprint electrical signal is transmitted to other electrical devices through the second pad 342. For example, the second pads 342 transmit fingerprint electric signals to the flexible circuit board, and the second pads 342 are electrically connected to pads on the flexible circuit board through solder balls.

In the embodiment of the application, the metal circuit layer is directly arranged on the optical filter 330, and the optical fingerprint chip 320 and the optical filter 330 are connected through the metal balls, so that the traditional mode of connecting the optical filter and the optical fingerprint chip through the transparent medium layer and the adhesive layer as shown in fig. 2 is changed, and the connecting mode of welding the metal balls is adopted, so that the fingerprint electric signal of the optical fingerprint chip can be transmitted, the fingerprint electric signal is not limited by the arc height of gold wires, and the thickness of the fingerprint identification device 300 can be effectively reduced.

In addition, in the embodiment of the present application, the optical filter 330 is externally arranged on the optical fingerprint chip 320, and does not warp the optical fingerprint chip 320, so that the performance of the optical fingerprint chip can be improved while the thickness of the fingerprint recognition device is reduced compared with the fingerprint recognition device 200 in fig. 3.

Optionally, the metal wiring layer 340 is used to form a Fan-out wafer level package (Fan-out Wafer Level Package, fan-out WLP) of the optical fingerprint chip 320.

Specifically, the metal circuit layer 340 may also be referred to as a redistribution layer (Redistribution Layer, RDL), and the metal circuit layer 340 may be one or more layers, and the number and the pitch of the pads are designed according to the area of the metal circuit layer 340 on the optical filter 330, which is not limited to the area of the optical fingerprint chip 320. And the optical filter 330 is integrated while the multi-pin optical fingerprint chip 320 is packaged at the wafer level, so that the performance of the optical fingerprint chip 320 in various aspects can be improved.

Fig. 5a and 5b show schematic structural views of two filters 330 and their lower surface film layers.

As shown in fig. 5a, in a structure of the optical filter 330 and the lower surface film layer thereof, the material of the metal circuit layer is generally copper (Cu), and in order to enhance the adhesion of the copper metal circuit layer 340 on the optical filter 330, a transition glue layer 370 is prepared between the optical filter 330 and the metal circuit layer 340. On the lower surface of the transition glue layer 370, a metal line layer 340 is prepared again, a first protective glue layer 350 is prepared around and on the lower surface of the metal line layer 340, and areas for electrical connection such as a first pad and a second pad are formed on the metal line layer 340 by exposing and etching the first protective glue layer 350.

The transition glue layer 370 and the first protective glue layer 350 are generally organic film layers, the thickness is generally about 8 to 10 μm, the thickness of the entire fingerprint identification device is greatly increased by adopting the transition glue layer 370, and the three-layer structure of the transition glue layer 370, the metal circuit layer 340 and the first protective glue layer 350 can also cause the increase of the process cost and the complexity of the process.

Fig. 5b is an enlarged view of a portion of the filter 330 and the lower surface film layer in fig. 4. As shown in fig. 5b, the metal circuit layer 340 is directly grown on the lower surface of the optical filter 330, and in order to increase the adhesion between the metal circuit layer 340 and the optical filter 330, in the embodiment of the present application, the material of the metal circuit layer 340 is aluminum (Al).

Optionally, to enhance the electrical performance of the metal circuit layer 340, the material of the metal circuit layer 340 may also be an aluminum-copper alloy, where the mass fraction of copper in the aluminum-copper alloy is less than 5%. The aluminum copper alloy can meet the adhesion between the metal circuit layer 340 and the optical filter 330, and can ensure the electrical properties such as conductivity and the like of the metal circuit layer 340.

It should be understood that the metal circuit layer 340 may also be an alloy material of aluminum and other metals, such as an aluminum-gold alloy, an aluminum-silver alloy, and the like, which is not limited in the embodiment of the present application.

Optionally, when the metal circuit layer 340 is an aluminum-gold alloy, the mass fraction of gold in the aluminum-gold alloy is less than 5%; alternatively, when the metal wiring layer 340 is an aluminum-silver alloy, the mass fraction of silver in the aluminum-gold alloy is less than 5%.

Specifically, a metal layer may be prepared on the lower surface of the optical filter 330 using various plating methods to form the metal wiring layer 340. Various coating methods include, but are not limited to: chemical vapor deposition (Chemical Vapor Deposition, CVD), physical vapor deposition (Physical Vapor Deposition, PVD), physical deposition, and the like, wherein physical vapor deposition methods include, but are not limited to: sputter coating (Sputtering), evaporation coating (Deposition), pulsed laser Deposition (Pulsed Laser Deposition, PLD) molecular beam epitaxy (Molecular beam epitaxy, MBE), and the like.

Alternatively, the thickness of the metal layer prepared by the above-mentioned coating method is 100 to 3000nm, in other words, the thickness of the metal wiring layer 340 is 100 to 3000nm. Preferably, the thickness of the metal wiring layer 340 is 200 to 800nm.

Alternatively, the metal wiring layer 340 may be formed on the above metal layer using Photolithography (Photolithography) and Etching (Etching) processes in a semiconductor process.

Optionally, a Lift-off (Lift-off) process, also known as a Metal Lift-off process (Metal Lift-off Technology), may also be used to form the Metal wiring layer 340 on the Metal layer. The metal circuit layer with more accurate size and steep pattern edge can be obtained by using the Lift-off process.

After the metal line layer 340 is formed on the lower surface of the optical filter 330, a plurality of plating methods may be used to form the first protective adhesive layer 350 on and around the lower surface of the metal line layer. Likewise, the coating method for preparing the first protective adhesive layer includes, but is not limited to: CVD, PVD, and the like. Among them, chemical vapor deposition CVD includes, but is not limited to: atmospheric pressure chemical vapor deposition (Atmospheric Pressure Chemical Vapor Deposition, APCVD), low pressure chemical vapor deposition (Low Pressure Chemical Vapor Deposition, LPCVD), plasma enhanced chemical vapor deposition (Plasma Enhanced Chemical Vapor Deposition, PECVD), high density plasma chemical vapor deposition (High Density Plasma Chemical Vapor Deposition, HDPCVD), and the like.

In an embodiment of the present application, the material of the first protective adhesive layer 350 may be an inorganic material or an organic material. Preferably, the first protective gel layer 350 is an inorganic material, including any one or more of the following materials: silicon oxide (SiO) ₂ ) Silicon nitride (SiN) _x ) Silicon oxynitride (SiO) _x N _y )。

Optionally, the thickness of the first protective adhesive layer 350 prepared by the above-mentioned coating method is 100-3000 nm. Preferably, the thickness of the first protective adhesive layer 350 is 100 to 1000nm.

Alternatively, the first protective glue layer 350 may be processed to form pads on the metal wiring layer 340, such as the first and second pads 341 and 342 described above, using a photolithography and Etching (Etching) process in a semiconductor process, or a lift-off process.

In the embodiment of the application, only the metal circuit layer 340 and the first protective adhesive layer 350 are prepared and formed on the lower surface of the optical filter 330, and the transition adhesive layer is not required to be prepared, so that the thickness of the lower surface film layer of the optical filter 330 is greatly reduced. And the two-layer film structure and the metal circuit layer 340 are mainly prepared from metal aluminum, so that the process cost and the process complexity can be reduced.

In addition, in the embodiment of the present application, the optical filter 330 may include a filter layer 331 and a transparent substrate 332. Optionally, the filter layer 331 may be formed on any one of the upper surface or the lower surface of the transparent substrate 332, specifically, in the filter 330, the filter layer 331 is used to transmit the optical signal of the target band and filter the optical signal of the non-target band, and the transparent substrate 331 is made of a material with a certain strength and is used to provide support for the optical fingerprint chip 320 connected thereto, without having a filtering function.

Alternatively, the filter layer 331 may be formed by coating a transparent substrate 332 by various coating methods, for example, a multi-layer coating method is performed on the transparent substrate by vapor deposition to obtain the filter layer 331, and the filter layer 331 may include an oxide layer of silicon and an oxide layer of titanium.

Alternatively, the number of layers of the filter layer 331 may be between 10 and 80 layers.

Alternatively, the transparent substrate 332 may be alkali or alkali-free glass having a thickness of 0.1 to 0.7mm.

It should be understood that the transparent substrate 332 may also be other transparent materials, including organic or inorganic transparent materials, such as crystal, resin, etc., which are not limited in this embodiment of the present application.

Preferably, as shown in fig. 5b, the filter layer 331 is formed on both the upper and lower surfaces of the transparent substrate 332.

Alternatively, the number of layers of the filter layer 331 on the upper surface of the transparent substrate 332 may be between 10 and 80 layers, and similarly, the number of layers of the filter layer 331 on the lower surface of the transparent substrate 332 may be between 10 and 80 layers.

In the embodiment of the present application, by sequentially coating the upper and lower surfaces of the transparent substrate 332, the warpage of the transparent substrate 332, that is, the optical filter 330, can be controlled, for example, coating the upper surface of the transparent substrate 332 to cause the transparent substrate to warp in the first direction, coating the lower surface of the transparent substrate 332 to reduce the warpage of the transparent substrate in the first direction, so that the transparent substrate returns to a flat state.

Fig. 6 shows a schematic diagram of a structure of an optical fingerprint chip and a filter connected by bumps (bumps) and solder balls.

As shown in fig. 6, the pads in the metal wiring layer 340 include a first pad 341 and a second pad 342, and the surfaces of the first pad 341 and the second pad 342 are grown with bumps 361 to facilitate connection of the solder balls 360.

Likewise, bumps 361 are grown on the surface of the chip pads 322 in the optical fingerprint chip 320 for connection with solder balls 360. Alternatively, the metal circuit layer in the optical fingerprint chip 320 may be the same as the material of the metal circuit layer 340 on the lower surface of the optical filter 330, and the chip pad 322 is the same as the material of the first pad 341 and the second pad 342.

Alternatively, the material of the solder balls 360 may be gold (Au).

In one possible embodiment, when the materials of the first pad 341, the second pad 342, and the chip pad 322 are copper, in order to enhance the connection bonding force between metallic copper and metallic gold, the bump 361 is nickel palladium gold (NiPdAu).

Optionally, a nickel-palladium-gold bump 361 is formed on the surfaces of the first pad 341 and the second pad 342 on the lower surface of the filter 330, and a nickel-palladium-gold bump 361 is also formed on the chip pad 322 of the optical fingerprint chip 320, and then the nickel-palladium-gold bump 361 on the first pad 341 and the chip pad 322 is connected through the gold solder ball 360, so as to improve the connection reliability.

Due to the problem of the connection bonding force between the metal gold and the metal copper, nickel-palladium-gold bumps are required to be grown on the surface of the copper pads before the solder balls are connected with the pads, so that the bonding force is enhanced, and the complexity of the process is increased.

In another possible embodiment, when the materials of the first pad 341, the second pad 342, and the chip pad 322 are aluminum, or an aluminum copper alloy or other alloy, the metallic aluminum and the metallic gold have good connection bonding force. Thus, in an embodiment of the present application, the material of the bump 361 grown on the pad surface may be gold, and Jin Hanqiu 360 is directly connected to the gold bump 361. Compared with the grown nickel palladium gold bump, the grown gold bump has simple process, and the thickness of the gold bump is smaller than that of the nickel palladium gold bump.

Alternatively, in a third possible embodiment, when the materials of the first pad 341, the second pad 342, and the chip pad 322 are aluminum, or an aluminum-copper alloy or other alloys, as shown in fig. 4, the Jin Hanqiu 360 directly connects the first pad 341 and the chip pad 322, in this connection manner, no bump needs to be prepared on the pad surface, and the pad is directly connected by a gold solder ball, so that the process is simpler, the connection manner is easier to implement, and the process yield can be improved.

Optionally, in one embodiment of the present application, the fingerprint identification device 300 further comprises:

an optical component 310, disposed between the optical filter 330 and the optical fingerprint chip 320, for guiding or converging the fingerprint light signal from above the display screen to the optical fingerprint chip 320.

Alternatively, the optical component 310 may correspond to the optical component 132 described in fig. 1, and the specific implementation may refer to the related description in the embodiment shown in fig. 1, which is not repeated here for brevity.

Optionally, the optical component 310 may specifically include a light guiding layer or light path guiding structure, and other optical elements, which is mainly used for guiding the reflected light reflected from the finger surface to the sensing array 321 in the optical fingerprint chip 320 for optical detection.

In particular implementations, optical component 310 may be packaged within optical fingerprint chip 320, or optical component 310 may be disposed external to optical fingerprint chip 320, such as by attaching optical component 310 over optical fingerprint chip 320, or by integrating some of the components of optical component 320 within optical fingerprint chip 320.

In one possible embodiment, as shown in fig. 7, the optical assembly 310 includes: at least one light blocking layer 311 and a microlens array 312;

The at least one light blocking layer 311 is provided with a plurality of light-passing holes;

the micro lens array 312 is disposed above the at least one light blocking layer 311, and is configured to collect the fingerprint light signals reflected or scattered by the finger to the plurality of light passing holes of the at least one light blocking layer 311, and the fingerprint light signals are transmitted to the optical fingerprint chip 320 through the plurality of light passing holes of the at least one light blocking layer 311.

The at least one light blocking layer 311 may be formed by semiconductor process growth or other processes, for example, atomic layer deposition, sputter coating, electron beam evaporation coating, ion beam coating, etc. to prepare a thin film of non-light transmissive material, and then performing hole pattern lithography and etching to form a plurality of light transmissive holes. The at least one light blocking layer 311 can block optical interference between adjacent micro lenses, and enable the optical signals corresponding to the sensing units to be converged into the light passing holes through the micro lenses and transmitted to the sensing units in the optical fingerprint chip through the light passing holes so as to perform optical fingerprint imaging.

The microlens array 312 is formed of a plurality of microlenses, which may be formed over the at least one light blocking layer 311 by a semiconductor growth process or other process, and each microlens may correspond to one of the sensing units of the optical fingerprint chip 320, respectively.

In another possible embodiment, as shown in fig. 8, the optical assembly 310 includes a lens assembly 314 having at least one lens group of spherical or aspherical optical lenses for converging the reflected light reflected from the finger to the sensing units of the optical fingerprint chip 320 thereunder, so that a plurality of sensing units can image based on the reflected light, thereby obtaining a fingerprint image of the finger. Optionally, the lens assembly 314 may also have a pinhole formed in its optical path that may cooperate with an optical lens to expand the field of view of the fingerprint identification device to enhance the fingerprint imaging effect of the fingerprint identification device 300.

Alternatively, as shown in fig. 8, the lens assembly 314 may be disposed between the optical filter 330 and the optical fingerprint chip 320 by the fixing device 315.

Alternatively, the fixing device 315 may be a bracket or a lens barrel, in which one or more optical lenses of the lens assembly 314 are fixed, for fixing the lens assembly 314 above the optical fingerprint chip 320, and the optical signal passes through the lens assembly 314 and then enters the optical fingerprint chip 320. Alternatively, when the fixing device 315 is a lens barrel, the fixing device 315 may further include a lens holder, where the lens barrel and the lens holder may be two separate components and may be fixed together by a threaded connection, and the lens holder may also be configured as an integral structure with the lens barrel.

Alternatively, the optical component 310 may be fixed above the optical fingerprint chip 320 by a light-transmitting adhesive material such as an adhesive glue.

Optionally, in an embodiment of the present application, as shown in fig. 4 and fig. 7 to fig. 8, the middle area of the metal circuit layer 310 and the first protective adhesive layer 350 is hollowed out, the optical component 310 and the optical fingerprint chip 320 are disposed below the hollowed-out area, the optical component 310 is configured to collect the fingerprint light signal from the finger above the display screen to the optical fingerprint chip 320, and the optical fingerprint chip 320 is configured to receive the fingerprint light signal and convert the fingerprint light signal into a corresponding fingerprint electrical signal so as to obtain the fingerprint information of the finger.

That is, the structure for realizing the electrical connection is provided, for example, the first bonding pad and the second bonding pad are arranged in the edge area below the optical filter, and the middle area of the optical filter is hollowed out for transmitting the optical signal for fingerprint identification.

In one embodiment, the area of the hollowed-out area is larger than the sensing area of the optical fingerprint chip 320, or the area of the hollowed-out area is larger than the area of the micro lens array 312, so that the optical fingerprint chip 320 can receive enough optical signals for optical fingerprint recognition.

Optionally, the optical component 310 is disposed in a hollowed-out area between the optical filter 330 and the optical fingerprint chip 320, and an air gap is formed between the optical component 310 and the optical filter 330.

It should be noted that, in the actual product, the thicknesses of the metal circuit layer 340 and the first protective adhesive layer 350 are relatively thin, and in the stacked structure shown in fig. 2 to 8, the thicknesses of the structures and the specific electrical connection relationship are relatively thick, which should be understood that the thicknesses of the structures and the relative thicknesses between the structures in the stacked structure are only illustrative, and should not be construed as limiting the embodiments of the present application.

Fig. 9 is a schematic block diagram of another fingerprint recognition device 300 according to an embodiment of the present application.

As shown in fig. 9, the fingerprint recognition device 300 further includes: a flexible circuit board 380, the flexible circuit board 380 being disposed under the optical filter 330, and a circuit board pad 381 being disposed on an upper surface of the flexible circuit board 380.

Through setting up first pad and second pad at the lower surface of light filter, realize the electrical connection of flexible circuit board's pad and the pad of optical fingerprint chip through this first pad and second pad, optical fingerprint chip is used for receiving the fingerprint light signal that comes from the user's finger reflection above the display screen or scatter, carry out photoelectric conversion to this fingerprint light signal and obtain corresponding electrical signal, further transmit this electrical signal to other peripheral circuits or other components in the electronic equipment through flexible circuit board, for example processing circuit, thereby this processing circuit can carry out further processing, for example fingerprint identification to this electrical signal.

Because the flexible circuit board 380 is softer and usually needs to be supported by the reinforcing plate, the thickness of the reinforcing plate is thicker, and is usually more than 100 μm, the thickness of the fingerprint identification device is greatly increased, in the embodiment of the application, the optical filter 330 is provided with transparent base materials such as glass and the like, and has a certain supporting effect, the flexible circuit board 380 is connected to the second bonding pad 342 on the optical filter 330 through the solder balls, and the solder balls have supporting and fixing effects relative to gold wires, so that the flexible circuit board 380 can play a role in reinforcing and supporting through the optical filter 330, therefore, the fingerprint identification device in the embodiment of the application can effectively reduce the overall thickness of the fingerprint identification device without arranging the reinforcing plate, and is beneficial to meeting the requirements of lightening and thinning of electronic equipment.

Optionally, in some cases, if the assembly space of the electronic device is sufficient, a reinforcing plate may be disposed under the flexible circuit board 380, so as to provide further support and reinforcement to the flexible circuit board 380.

Alternatively, in one embodiment of the present application, the flexible circuit board 380 is disposed at the periphery of the optical fingerprint chip 320. That is, the flexible circuit board 380 and the optical fingerprint chip 320 do not overlap in the vertical direction.

In one embodiment, the middle area of the flexible circuit board 380 is hollowed out, and the optical fingerprint chip is disposed in the hollowed out area. Compared with the thickness of the flexible circuit board, the thickness of the fingerprint identification device is reduced. In this case, the flexible circuit board 380 is located around the optical fingerprint chip 320 in a plan view.

In other alternative embodiments, the flexible circuit board 380 may be disposed outside of the edge region of the optical fingerprint chip 320. In this case, the flexible circuit board 380 is located at one side of the optical fingerprint chip 320 in a plan view.

Alternatively, the flexible circuit board 380 may be perforated at one side of the flexible circuit board 380, and the optical fingerprint chip 320 may be disposed in the perforated, or the flexible circuit board 380 may be disposed directly outside the edge region of the optical fingerprint chip 320.

Alternatively, in one embodiment of the present application, the chip pad 322 is disposed at an edge region of the optical fingerprint chip 320, and the circuit board pad 381 on the flexible circuit board 380 is disposed at the edge region of the flexible circuit board 380 and near one side of the optical fingerprint chip 320. That is, the chip pad 322 and the circuit board pad 381 are disposed at one ends of the optical fingerprint chip 320 and the flexible circuit board 380, respectively, which are close to each other. The first pad 341 and the second pad 342 are formed at an edge area of the optical filter 330 and above the chip pad 322 and the circuit board pad 381. In this way, the chip pad 322 and the circuit board pad 381 can be electrically connected with each other through the solder balls in the vertical direction, which is simple and easy to implement, and can improve the stability and reliability of the electrical connection between the pads, and can better provide reinforcement and support for the flexible circuit board.

Optionally, as shown in fig. 9, in an embodiment of the present application, the fingerprint identification device 300 further includes:

a second protective adhesive layer 390 for covering the first pads 341, the second pads 342, the chip pads 322 on the optical fingerprint chip and the circuit board pads 381 on the flexible circuit board.

After forming the first protective glue layer 350, a second protective glue layer 390 may be further formed at the electrical connection area to protect and strengthen the pads and solder balls. Specifically, the electrical connection region may be dispensed to form the second protective adhesive layer 390.

Further, in order to avoid overflowing to the area of the optical component 310 when preparing the second protective adhesive layer 390, the fingerprint recognition device 300 further includes:

the retaining wall structure 391 is disposed between the second protective adhesive layer 390 and the optical assembly 310, and is used for isolating the optical assembly 310 from the second protective adhesive layer 390.

By disposing the chip pad 322 at the edge region of the optical fingerprint chip 320, the circuit board pad 381 of the flexible circuit board 380 is disposed at a side of the flexible circuit board 380 near the optical fingerprint chip 320, and the metal wire layer 340 and the first protective adhesive layer 350 are disposed at the edge region of the optical filter 330 and over the chip pad 322 and the circuit board pad 381, so that the second protective adhesive layer 390 for covering the electrical connection region is also formed at the edge region of the optical filter 330. Further, by disposing the retaining wall structure 391 at the position of the optical filter 330 near the inner side, it is able to avoid the influence on the fingerprint recognition performance caused by the overflow of the optical component 310 under the middle region of the optical filter 330 when the second protective adhesive layer 390 is prepared.

In some embodiments, the retaining wall structure 391 is disposed inside the die pad 322 and outside the optical assembly 310, i.e., the retaining wall structure 391 is disposed between the die pad 322 and the optical assembly 310.

Optionally, the retaining wall structure 391 is disposed on the upper surface of the optical fingerprint chip 320 or the lower surface of the first protective adhesive layer 350.

For example, after the first protective adhesive layer 350 is prepared, a retaining wall structure 391 may be further prepared on the surface of the first protective adhesive layer 350, for example, the retaining wall structure 391 may be prepared on the surface of the first protective adhesive layer 350 near the inner side. Optionally, the lower surface of the retaining wall 391 is higher than the upper surface of the optical fingerprint chip 320 to avoid subsequent dummy solder connections between the solder balls 360 and the chip pads 322, and between the solder balls and the circuit board pads 381.

For another example, the retaining wall structure 391 may be formed on the surface of the optical fingerprint chip 320, for example, the retaining wall structure 391 may be formed on the surface of the optical fingerprint chip 320 inside the first pad 311 and outside the optical member 310. Optionally, the upper surface of the retaining wall structure 391 is lower in height than the lower surface of the first protective glue layer 350 to avoid a dummy bond between the solder ball and the chip pad 322 and a dummy bond between the solder ball and the circuit board pad 381.

It should be noted that, in the example shown in fig. 9, the second protective adhesive layers 390 are disposed on two sides of the optical filter 330, and in a top view, the second protective adhesive layers 390 may be filled around the optical filter 330, so that a closed space may be formed between the optical fingerprint chip 320 and the optical filter 330 by the second protective adhesive layers 390, and an air gap is formed between the optical component and the optical filter, which may ensure that the optical filter does not contact the upper surface of the optical component when the display screen is pressed or the electronic device falls or collides, and may not affect the stability and performance of fingerprint recognition of the fingerprint recognition device 300.

The embodiment of the application also provides an electronic device, as shown in fig. 10, the electronic device 400 may include a display screen 410 and a fingerprint recognition device 420, where the fingerprint recognition device 420 is disposed below the display screen 410.

Alternatively, the fingerprint recognition device 420 may be the fingerprint recognition device 300 in the above embodiment, and the specific structure may refer to the related description above, which is not repeated here.

Alternatively, in one embodiment of the present application, the display screen 410 may be embodied as a self-luminous display screen (such as an OLED display screen), and includes a plurality of self-luminous display units (such as OLED pixels or OLED light sources). When the optical image acquisition system is a biological feature recognition system, a part of self-luminous display units in the display screen can be used as an excitation light source for biological feature recognition by the biological feature recognition system and used for emitting light signals to a biological feature detection area for biological feature detection.

It should be understood that the specific examples of the embodiments of the present application are intended to facilitate a better understanding of the embodiments of the present application by those skilled in the art, and are not intended to limit the scope of the embodiments of the present application.

It is to be understood that the terminology used in the embodiments of the application and in the appended claims is for the purpose of describing particular embodiments only, and is not intended to be limiting of the embodiments of the application. For example, as used in the embodiments of the application and the appended claims, the singular forms "a," "an," and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise.

Those of ordinary skill in the art will appreciate that the elements of the examples described in connection with the embodiments disclosed herein may be implemented as electronic hardware, computer software, or combinations of both, and that the elements and steps of the examples have been described above generally in terms of functionality for clarity of understanding of interchangeability of hardware and software. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the solution. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present application.

In the several embodiments provided in the present application, it should be understood that the disclosed system and apparatus may be implemented in other manners. For example, the apparatus embodiments described above are merely illustrative, e.g., the division of the units is merely a logical function division, and there may be additional divisions when actually implemented, e.g., multiple units or components may be combined or integrated into another system, or some features may be omitted or not performed. In addition, the coupling or direct coupling or communication connection shown or discussed with each other may be an indirect coupling or communication connection via some interfaces, devices, or elements, or may be an electrical, mechanical, or other form of connection.

The units described as separate units may or may not be physically separate, and units shown as units may or may not be physical units, may be located in one place, or may be distributed on a plurality of network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the embodiment of the present application.

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

The integrated units, if implemented in the form of software functional units and sold or used as stand-alone products, may be stored in a computer readable storage medium. Based on such understanding, the technical solution of the present application is essentially or a part contributing to the prior art, or all or part of the technical solution may be embodied in the form of a software product stored in a storage medium, comprising several instructions for causing a computer device (which may be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the method according to the embodiments of the present application. And the aforementioned storage medium includes: a U-disk, a removable hard disk, a Read-Only Memory (ROM), a random access Memory (RAM, random Access Memory), a magnetic disk, or an optical disk, or other various media capable of storing program codes.

While the application has been described with reference to certain preferred embodiments, it will be understood by those skilled in the art that various changes and substitutions of equivalents may be made and equivalents will be apparent to those skilled in the art without departing from the scope of the application. Therefore, the protection scope of the application is subject to the protection scope of the claims.

Claims

1. The utility model provides a fingerprint identification device for set up in order to realize fingerprint identification below electronic equipment's the display screen, includes:

the optical filter is arranged above the optical fingerprint chip and is provided with an air gap with the optical fingerprint chip, a metal circuit layer is directly formed on the lower surface of the optical filter, and the metal circuit layer is connected with the optical fingerprint chip through a solder ball and is used for transmitting fingerprint electric signals of the optical fingerprint chip.

2. The fingerprint recognition device of claim 1, wherein the metal wiring layer is used to form a fan-out wafer level package of the optical fingerprint chip.

3. The fingerprint recognition device of claim 1, wherein the material of the metal line layer comprises aluminum; and/or the thickness of the metal circuit layer is 100nm to 3000nm.

4. The fingerprint identification device according to claim 1, wherein the material of the metal circuit layer is an aluminum-copper alloy, wherein the mass fraction of copper in the aluminum-copper alloy is less than 5%;

5. The fingerprint recognition device according to any one of claims 1 to 4, wherein the metal circuit layer is a patterned circuit layer formed by directly plating a film on a lower surface of the optical filter by a physical vapor deposition method, and performing photolithography and etching processes or photolithography and lift-off processes.

6. The fingerprint recognition device according to any one of claims 1-4, wherein a first protective glue layer is provided on a surface of the metal wiring layer, and the metal wiring layer forms a bonding pad through the first protective glue layer, and the bonding pad is formed in an edge region of the optical filter.

7. The fingerprint recognition device according to claim 6, wherein bumps are grown on the surface of the pads, and the solder balls are connected with the pads through the bumps.

8. The fingerprint recognition device of claim 7, wherein the bumps are gold bumps.

9. The fingerprint recognition device according to claim 6, wherein the material of the first protective adhesive layer is an inorganic material, and the inorganic material is: one or more of silicon oxide, silicon nitride, silicon oxynitride; and/or the number of the groups of groups,

the thickness of the first protective adhesive layer is 100nm to 3000nm.

10. The fingerprint recognition device according to claim 6, wherein the first protective adhesive layer is a pattern layer formed by plating a film on the surface of the metal circuit layer by a chemical vapor deposition method, and performing a photolithography and etching process or a photolithography and stripping process.

11. The fingerprint identification device of claim 6, wherein the metal circuit layer and the first protective adhesive layer have a hollowed-out middle area, and the optical fingerprint chip is disposed below the hollowed-out area to receive a fingerprint light signal from a finger above the display screen, and the fingerprint light signal is used for detecting fingerprint information of the finger.

12. The fingerprint recognition device of claim 11, wherein the hollowed-out area is larger than the sensing area of the optical fingerprint chip.

13. The fingerprint recognition device according to any one of claims 1-4, wherein the optical filter comprises a transparent substrate, and the upper surface and the lower surface of the transparent substrate are respectively provided with an optical filter layer, and the optical filter layer is used for filtering optical signals of non-target wave bands through optical signals of target wave bands.

14. The fingerprint recognition device according to claim 13, wherein the filter layer on the upper surface of the transparent substrate is between 10 layers and 80 layers, and the coating layer on the lower surface of the transparent substrate is between 10 layers and 80 layers.

15. The fingerprint recognition device of claim 13, wherein the transparent substrate is alkali or alkali-free glass, and the glass has a thickness of 0.1 to 0.7mm.

16. The fingerprint recognition device of claim 13, wherein the target band is a visible light band.

17. The fingerprint recognition device according to claim 6, wherein a first pad and a second pad are formed on the metal wiring layer, the first pad being connected with a pad on the optical fingerprint chip through the solder ball;

the bonding pads on the optical fingerprint chip are used for transmitting the fingerprint electric signals to the first bonding pads, and the first bonding pads are used for transmitting the fingerprint electric signals to the second bonding pads.

18. The fingerprint recognition device of claim 17, wherein the second pad is configured to transmit the fingerprint electrical signal to a flexible circuit board, the flexible circuit board being disposed below the optical filter.

19. The fingerprint identification device of claim 18, wherein the fingerprint identification device further comprises: and the second bonding pad is connected with the bonding pad on the flexible circuit board through the solder ball connection.

20. The fingerprint recognition device of claim 18, wherein the flexible circuit board is disposed at a periphery of the optical fingerprint chip.

21. The fingerprint recognition device of claim 20, wherein the middle region of the flexible circuit board is hollowed out, and the optical fingerprint chip is disposed in the hollowed out region.

22. The fingerprint recognition device of claim 20, wherein the flexible circuit board is disposed outside an edge region of the optical fingerprint chip.

23. The fingerprint recognition device of claim 20, wherein the pads of the optical fingerprint chip are disposed at an edge region of the optical fingerprint chip, and the pads of the flexible circuit board are disposed at an edge region of the flexible circuit board and are adjacent to one side of the optical fingerprint chip.

24. The fingerprint identification device of claim 18, wherein the fingerprint identification device further comprises:

25. The fingerprint identification device of claim 24, wherein the fingerprint identification device further comprises:

26. The fingerprint identification device according to claim 25, wherein the optical component comprises at least one light blocking layer and a microlens array, the at least one light blocking layer being located below the microlens array, a plurality of light passing apertures being provided, the optical fingerprint chip being adapted to receive light signals converged into and passing through the plurality of light passing apertures via the microlens array.

27. The fingerprint identification device of claim 25, wherein the fingerprint identification device further comprises:

28. The fingerprint recognition device of claim 27, wherein the retaining wall structure is disposed on an upper surface of the optical fingerprint chip or a lower surface of the first protective adhesive layer.

29. The fingerprint recognition device according to claim 28, wherein if the retaining wall structure is disposed on the upper surface of the optical fingerprint chip, the upper surface of the retaining wall structure is lower than the lower surface of the first protective adhesive layer; or,

30. The fingerprint recognition device according to any one of claims 1-4, wherein the display screen is an OLED display screen, and the optical fingerprint chip uses a part of display units of the OLED display screen as an excitation light source for optical fingerprint detection.

31. An electronic device, comprising: display screen, and

a fingerprint recognition device as claimed in any one of claims 1 to 30, wherein the fingerprint recognition device is disposed below the display screen.

32. The electronic device of claim 31, wherein the display screen is an organic light emitting diode, OLED, display screen comprising a plurality of OLED light sources, wherein the fingerprint recognition device employs at least a portion of the OLED light sources as excitation light sources for optical fingerprint detection.