WO2017035765A1

WO2017035765A1 - Fingerprint imaging device structure and method for packaging the same

Info

Publication number: WO2017035765A1
Application number: PCT/CN2015/088695
Authority: WO
Inventors: Wei Fang; Hong Zhu; Yan LING; Yong Han
Original assignee: Shanghai Oxi Technology Co., Ltd
Priority date: 2015-09-01
Filing date: 2015-09-01
Publication date: 2017-03-09

Abstract

A fingerprint imaging device structure and a packaging method are provided. The fingerprint imaging device structure includes: a fingerprint imaging device (110) including a substrate (114), a sensor (111) disposed above the substrate (114), and a cap layer (113); and a housing (120), wherein the housing (120) is made of non-metallic material. The packaging method includes: providing a fingerprint imaging device (610); disposing one or more fingerprint imaging devices (610) into a mould (630); providing feeding material (621) of a housing (120); injecting the feeding material (621) into the mould (630) to form the housing (120), which packages the one or more fingerprint imaging devices (610). Accordingly, the packaging method is simple and low cost.

Description

FINGERPRINT IMAGING DEVICE STRUCTURE AND METHOD FOR PACKAGING THE SAME

TECHNICAL FIELD

The present disclosure generally relates to optical imaging fields, and more particularly, to a fingerprint imaging device structure and a process for the package.

BACKGROUND

Generally, fingerprint identification technology includes capturing a fingerprint image, and then comparing the fingerprint image with a pre-stored fingerprint image. Due to convenience for using fingerprint identification technology and uniqueness of fingerprints, fingerprint identification technology has been widely used in various fields, such as: security inspections by police or customs, access control systems, personal computers, mobile phones, etc.

However, in prior art, cost for packaging the fingerprint imaging device is high and the manufacturing process is complex. Therefore, there is a need for a new low cost process of packaging the fingerprint imaging device.

SUMMARY

According to embodiments of the present disclosure, a fingerprint imaging device structure is provided. The fingerprint imaging device structure includes a fingerprint imaging device which includes a substrate, a sensor disposed above the substrate, and a cap layer covering at least a part of the surface of the sensor. The fingerprint imaging device structure further includes a housing, which is made of non-metallic material and adapted to package the fingerprint imaging device.

In some embodiments, the housing is made of plastic compound or ceramic compound.

In some embodiments, the housing is made of epoxy compound.

In some embodiments, the sensor is disposed on the surface of the substrate； and the housing covers a peripheral part of the substrate.

In some embodiments, the substrate includes a printed circuit board, or a flexible printed circuit and a stiffener on which the flexible printed circuit is fixed.

In some embodiments, the sensor includes a first plurality of electrical pads, the substrate includes a second plurality of electrical pads, and the first plurality of electrical pads are connected with the second plurality of electrical pads through metal wires correspondingly； and the housing encapsulates the first plurality of electrical pads, the second plurality of electrical pads and metal wires.

In some embodiments, the sensor includes a third plurality of pads disposed on the surface of the sensor at a same side as the cap layer, the flexible printed circuit includes a fourth plurality of pads on one end, and the one end of flexible printed circuit is bended to connect the fourth plurality of pads with the third plurality of pads on the sensor correspondingly.

In some embodiments, the fingerprint imaging device further includes an wakeup device for wakeup the fingerprint imaging device to work.

In some embodiments, the wakeup device includes one or more electrical pads disposed on the substrate or on the sensor； and the housing further covers the surface of the electrical pad.

In some embodiments, the wakeup device further includes a touch chip which is adapted to detect the change of electronic signal on the electrical pad and to output a wakeup signal.

In some embodiments, the wakeup device further includes a microcontroller unit adapted to send a start instruction to the fingerprint imaging device for operating according to the wakeup signal from the touch chip.

In some embodiments, the fingerprint imaging device further includes a light source adapted to provide lights for imaging the fingerprint； and the housing covers the light source.

In some embodiments, the fingerprint imaging device further includes a readout chip by which the analog signals of the sensor is converted to digital signals, and the readout chip is disposed on a part of the surface of the sensor not being covered by the cap layer or on a part of the substrate not being covered by the sensor； and the housing covers the readout chip.

In some embodiments, the cap layer is a glass, a fiber of plate or a protect layer deposited on the sensor； and the housing covers a part of the cap layer and exposes another part of the surface of the cap layer for placing the fingerprint to be imaged.

In some embodiments, the fingerprint imaging device further includes a light guide plate disposed between the substrate and the sensor； and the housing covers periphery of the light guide plate.

In addition, embodiments of the present disclosure further provide a method for packaging a fingerprint imaging device, includes: providing one or more fingerprint imaging devices； disposing the one or more fingerprint imaging devices into a mould； providing feeding material of a housing； injecting the feeding material into the mould so as to form the housing, where the housing packages the one or more fingerprint imaging devices.

In some embodiments, the housing material comprises either plastic compounds or ceramic compounds.

In some embodiments, the plastic compounds comprise at least one of epoxy compounds.

In some embodiments, the method further comprises: preheating the mould before injecting the feeding material into the mould.

In some embodiments, the mould includes one or more cavities, and the one or more fingerprint imaging devices are packaged in the mould by one injection molding process.

For the fingerprint imaging device structure and the packaging method provided in the present disclosure, the housing is made of non-metallic material and is formed by injection molding. The injection molding process is easy to perform with low cost.

Furthermore, a wakeup device is configured to awaken the fingerprint imaging device so that the fingerprint imaging device is switched to an operating mode from hibernation, which makes the fingerprint imaging device structure more automatic.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 schematically illustrates a top view of the fingerprint imaging device structure according to an embodiment of the present disclosure.

FIG. 2 schematically illustrates a cross sectional view along line A-A’ in FIG. 1.

FIG. 3 schematically illustrates a 3D structure of an unpackaged fingerprint imaging device in FIG. 1.

FIG. 4 schematically illustrates a top view of a fingerprint imaging device including an wakeup device according to another embodiment of the present disclosure.

FIG. 5 schematically illustrates the structure of the awaking device in FIG. 4.

FIG. 6 schematically illustrates a cross sectional view of a fingerprint imaging device structure according to another embodiment of the present disclosure.

FIG. 7 schematically illustrates a cross sectional view of a fingerprint imaging device structure according to another embodiment of the present disclosure.

FIG. 8 schematically illustrates a cross sectional view of a fingerprint imaging device structure according to another embodiment of the present disclosure.

FIG. 9 schematically illustrates a cross sectional view of a fingerprint imaging device structure according to another embodiment of the present disclosure.

FIGs. 10-14 schematically illustrate cross sectional views of intermediate processes of packaging a fingerprint imaging device in an injection mould according to an embodiment of the present disclosure.

DETAILED DESCRIPTION

In order to clarify the objects, characteristics and advantages of the present disclosure, embodiments of the present disclosure will be described in detail in conjunction with the accompanying drawings. The disclosure will be described with reference to certain embodiments. Accordingly, the present disclosure is not limited to the embodiments disclosed. It will be understood by those skilled in the art that various changes may be made without departing from the spirit or scope of the disclosure.

Referring to FIG. 1, a top view of the fingerprint imaging device structure 100 is schematically illustrated. The fingerprint imaging device structure 100 includes a fingerprint imaging device 110 and a housing 120 packaging the fingerprint imaging device 100.

The housing 120 is made of non-metallic material. In some embodiments, the housing 120 is made of either plastic compounds or ceramic compounds. In some embodiments, the housing is made of epoxy compounds and formed by injection molding.

Referring to FIG. 2, a cross sectional view along line A-A’s hown in FIG. 1 is schematically illustrated. The fingerprint imaging device 110 in the fingerprint imaging device structure 100 is adapted to capture a fingerprint image. The 3D structure of the unpackaged fingerprint imaging device 110 in FIG. 2 is schematically illustrated in FIG. 3.

As shown in FIG. 2 and FIG. 3, the fingerprint imaging device 110 includes: a substrate 114, a sensor 111 disposed above the substrate 114 and a cap layer 113 covering at least a part of the surface of the sensor 111. The cap layer 113 defines a touch area of the fingerprint imaging device 110.

The sensor 111 is adapted to capture a fingerprint image and disposed on the surface of the substrate 114. The housing 120 covers a peripheral part of the substrate 114. In some embodiments, the substrate is a printed circuit board. It should be noted that the substrate 114 may be electrically connected with an external circuit. Therefore, the fingerprint imaging device 110 may further include a connector 140 disposed on the second surface of the substrate 114 to electrically connect with the external circuit.

The fingerprint imaging device 110 further includes a light source 112 adapted to provide incident lights. In some embodiments, the light source 112 is disposed adjacent to the sensor 111 and on the surface of the substrate 114. The lights emitted from the light source 112 are guided into the sensor 111 to illuminate an object to be imaged. The housing covers the light source 112.

The sensor 111 includes a first plurality of electrical pads 116f, the substrate 114 includes a second plurality of electrical pads 116s, and the first plurality of electrical pads 116f are electrically connected with the second plurality of electrical pads 116s via metal wires 116 correspondingly by press bonding or diffusion bonding. The first plurality of electrical pads 116f, the metal wires 116 and the second plurality of electrical pads 116s are adapted to transmit the signals between the sensor 111 and the substrate 114.

The housing 120 encapsulates the surface of the first plurality of electrical pads 116f, the second plurality of electrical pads 116s and the metal wires 116. In some embodiments, the first plurality of electrical pads 116f and the second plurality of electrical pads 116s may be made of conductive materials and the metal wires 116 may be gold wires.

The cap layer 113 covers at least a part of the surface of the sensor 111 so as to protect the sensor 111 and prevent the sensor 111 from being abraded. In some embodiments, the cap layer 113 covers a part of a surface of the sensor 111. The housing 120 covers a part of the cap layer 113 and exposes another part of the surface of the cap layer 113 used for placing fingers or other object to be imaged. In some embodiments, the cap layer 113 is a glass or a fiber of plate and connects with the sensor 111 using UV glue 113a.

In order to readout the fingerprint image obtained by the sensor 111, the fingerprint imaging device 110 further includes a readout chip 115 by which the analog signals of the sensor is converted to digital signals. In some embodiments, the readout chip 115 may be located on a part of the surface of the sensor 111, which is not covered by the cap layer 113. In some embodiments, the readout chip 115 may be mounted on the surface of the substrate 111, which is not covered by the sensor. In both situations, the housing 120 covers the readout chip 115.

In addition, the fingerprint imaging device 110 may further include an wakeup device 130 for providing more conveniences. Referring to FIG. 4, the top view of the fingerprint imaging device 110 including a wakeup device 130 is schematically illustrated.

The wakeup device 130 may enable the fingerprint imaging device 110 operate only when an object to be imaged touches the fingerprint imaging device structure 100. It may improve automation of the fingerprint imaging device structure 110.

The wakeup device 130 includes one or more electrical pads 131 disposed on the substrate 114 or on the sensor 111. The one or more electrical pads 131 may be configured to surround the sensor 111. The housing 120 further may cover the surface of the electrical pads 131.

In some embodiments, the number of electrical pads 131 may be two. The figures present a fingerprint imaging device using two electrical pads as example. The two electrical pads 131 may be disposed at two opposite sides of the sensor 111.

When a finger or other object to be imaged touches the fingerprint imaging device structure 100, specifically touches the electrical pad 131, the coupling capacity between the touch pad 131 and the earth may be changed. The kind of change may be detected and an instruction controlling the fingerprint imaging device may be formed according to the change.

Referring to FIG. 5, the structure of the wakeup device 130 is schematically illustrated. The awaking device includes a touch chip 132 and a microcontroller unit 133. The touch chip 132 is adapted to detect the change of electronic signal on both the electrical pad 131 and a finger and then output a wakeup signal. The microcontroller unit 133 is adapted to send a start instruction to a control device of the fingerprint imaging device 110 for operating according to the wakeup signal from the touch chip 132. In some embodiments, when the control device of fingerprint imaging device 110 receives the start instruction from the microcontroller unit 133, it starts to detect fingerprint image. In some embodiments, the touch chip 132 and the microcontroller unit 133 may both be located at the second surface of the substrate 114.

In some embodiments, the microcontroller unit 133 may be set to send the start instruction when the coupling capacities of the two touch pads 131 detected by the touch chip 132 are changed. In some embodiments, the microcontroller unit 133 may further be set to send the start instruction when the touch chip 132 detects the coupling capacities of one of the touch pads 131 is changed.

In some embodiments, the cap layer may also be a deposited protect layer. FIG. 6 schematically illustrates a cross sectional view of the fingerprint imaging device structure 200 using a deposited protect layer according to another embodiment of the present disclosure.

The deposited protect layer may be SiO₂ or Al₂O₃ and may be deposited using CVD, PVD, etc. In this case, there is no UV glue between the protect layer and the sensor 211. The protect layer can be deposited on the sensor 211 directly. By using the protect layer as the cap layer 213 instead of the glass, thickness of the image device may be reduced and the manufacturing process may be more compatible with CMOS process.

Referring to FIG. 7, a cross sectional view of the fingerprint imaging device structure 300 according to another embodiment of the present disclosure is schematically illustrated. In order that the lights uniformly propagate to the finger, in some embodiments, the fingerprint imaging device may further include a light guide plate 317 disposed between the substrate 314 and the sensor 311. The housing 320 may cover the periphery of the light guide plate 317.

It should be noted that for the fingerprint imaging device structure with a light guide plate, the readout chip may be disposed on the surface of the sensor or on the surface of the substrate. Similarly, the cap layer may be the glass or the deposited protect layer.

In some embodiments, the substrate may be a flexible printed circuit and a stiffener on which the flexible printed circuit is fixed. FIG. 8 schematically illustrates a cross sectional view of the fingerprint imaging device structure 400 using a flexible printed circuit 414a and a stiffener 414b as a substrate 414 according to another embodiment of the present disclosure

Similar to the embodiments mentioned above, the readout chip may be located on the surface of the sensor or on the surface of the substrate in the fingerprint imaging device structure with a flexible printed circuit and a stiffener. The cap layer may be the glass or the deposited protect layer and the fingerprint imaging device structure may or may not also contain a light guide plate.

In some embodiments, the wire connecting substrate and sensor may be omitted by electrically connecting the flexible printed circuit with the sensor directly. Referring to FIG. 9, a cross sectional view of the fingerprint imaging device structure 500 according to another embodiment of the present disclosure is schematically illustrated.

The sensor 511 comprises a third plurality of pads disposed on the surface of the sensor 511 at the same side as the cap layer 513 is disposed, the flexible printed circuit 514a includes a fourth plurality of pads on one end, the one end of the flexible printed circuit 514a is bended to electrically connect the third plurality of pads with the fourth plurality of pads on the sensor 511 correspondingly.

It should be noted that in the embodiments with the bending flexible printed circuit, a glass or a protect layer may be used as the cap layer 513, and between the flexible printed circuit 514a and the sensor 511, there may or may not have a light guide plate.

Furthermore, the present disclosure also provides a method for packaging a fingerprint imaging device.

Referring from FIG. 10 to FIG. 14, cross sectional views of a fingerprint imaging device structure at various stages of the method for packaging a fingerprint imaging device according to another embodiment of the present disclosure are illustrated.

Referring to FIG. 10, providing one or more fingerprint imaging devices 610 as described above.

Referring to FIG. 11, placing the one or more fingerprint imaging devices 610 into a mould 630.

The mould 630 is used to form a housing, which packages the fingerprint imaging device 610. The mould 630 may include one or more cavities fitting for the one or more fingerprint imaging devices 610. Each cavity is adapted to accommodate one fingerprint imaging device 610. In the figures as illustrated in FIG. 10 to 14, two cavities and two fingerprint imaging devices are taken as example.

Thereafter, the method further includes preheating the mould before injecting the feeding material into the cavity. In some embodiments, the mould 630 is preheated to a temperature between 80℃ and 90℃.

Still referring to FIG. 11, providing feeding material 621 of a housing.

The feeding material 621 is used to be injected into the mould 630 so as to form a housing. And the housing material may be plastic compounds or ceramic compounds. In some embodiments, the housing material may be epoxy compounds.

Referring to FIG. 12 and FIG. 13, injecting the feeding material 621 into the mould 630 so as to form the housing, which packages the one or more fingerprint imaging devices 610 respectively.

After being injected into the mould, the feeding material cools down and cures to form the housing packaging the fingerprint imaging device.

Referring to FIG. 14, after the feeding material is cured and the housing 620 is formed, the packaged fingerprint imaging device is taken out from the mould 630.

The above described and other features and advantages will become more apparent to those of ordinary skill in the art by describing in detail exemplary embodiments with reference to the attached drawings. The same reference numbers may be used in different drawings to identify the same or similar elements. The figures are not drawn to scale, and the emphasis is to illustrate the disclosure instead.

Claims

A fingerprint imaging device structure, comprising:

a fingerprint imaging device, comprising

a substrate,

a sensor disposed above the substrate, and

a cap layer covering at least a part of the surface of the sensor； and

a housing, adapted to package the fingerprint imaging device；

wherein the housing is made of non-metallic material.
The device structure according to claim 1, wherein the housing is made of plastic compounds or ceramic compounds.
The device structure according to claim 2, wherein the housing is made of epoxy compound.
The device structure according to claim 1, wherein the sensor is disposed on the surface of the substrate； and the housing covers a peripheral part of the substrate.
The device structure according to claim 1, wherein the substrate comprises a printed circuit board, or a flexible printed circuit and a stiffener on which the flexible printed circuit is fixed.
The device structure according to claim 1, wherein the sensor comprises a first plurality of electrical pads, the substrate comprises a second plurality of electrical pads, and the first plurality of electrical pads are connected with the second plurality of electrical pads through metal wires correspondingly by press bonding or diffusion bonding； and the housing encapsulates the surface of the first plurality of electrical pads, the second plurality of electrical pads and metal wires.
The device structure according to claim 5, wherein the sensor comprises a third plurality of pads disposed on the surface of the sensor at the same side as the cap layer, the flexible printed circuit comprises a fourth plurality of pads on one end, and the one end of flexible printed circuit is bended to electrically connect the third plurality of pads with the fourth plurality of pads on the sensor correspondingly.
The device structure according to claim 1, wherein the fingerprint imaging device further comprises a wakeup device for wakeup the fingerprint imaging device.
The device structure according to claim 8, wherein the wakeup device comprises one or more electrical pads disposed on the substrate or on the sensor； and the housing further covers the surface of the electrical pad.
The device structure according to claim 9, wherein the wakeup device further comprises a touch chip, the touch chip is adapted to detect the change of electronic signal on the electrical pad and to output a wakeup signal.
The device structure according to claim 10, further comprising a microcontroller unit adapted to send a start instruction to the fingerprint imaging device according to the wakeup signal from the touch chip.
The device structure according to any one of claim 1 to 11, wherein the fingerprint imaging device further comprises a light source adapted to provide lights for imaging the fingerprint； and the housing covers the light source.
The device structure according to any one of claim 1 to 11, wherein the fingerprint imaging device further comprises a readout chip by which the analog signals of the sensor is converted to digital signals, and the readout chip is disposed on a part of the surface of the sensor not being covered by the cap layer or on a part of the substrate not being covered by the sensor； and the housing covers the readout chip.
The device structure according to any one of claim 1 to 11, wherein the cap layer is a glass, a fiber of plate or a protect layer disposed on the sensor； and the housing covers a part of the cap layer and exposes another part of the surface of the cap layer for placing the fingerprint to be imaged.
The device structure according to any one of claims 1 to 11, wherein the fingerprint imaging device further comprises a light guide plate disposed between the substrate and the sensor, and the housing covers periphery of the light guide plate.
A method for packaging a fingerprint imaging device, comprising:

providing one or more fingerprint imaging devices；

disposing the one or more fingerprint imaging devices into a mould；

providing feeding material of a housing；

injecting the feeding material into the mould so as to form the housing, where the housing packages the one or more fingerprint imaging devices.
The method according to claim 16, wherein the housing material comprises either plastic compounds or ceramic compounds.
The method according to claim 17, wherein the plastic compounds comprise at least one of epoxy compounds.
The method according to claim 16, further comprising: preheating the mould before injecting the feeding material into the mould.
The method according to claim 16, wherein the mould includes one or more cavities and the one or more fingerprint imaging devices are packaged in the mould by one injection molding process.