WO2018223335A1

WO2018223335A1 - Fingerprint sensing apparatus and electronic device

Info

Publication number: WO2018223335A1
Application number: PCT/CN2017/087595
Authority: WO
Inventors: 林峰
Original assignee: 深圳信炜科技有限公司
Priority date: 2017-06-08
Filing date: 2017-06-08
Publication date: 2018-12-13
Also published as: CN209447146U

Abstract

Provided are a fingerprint sensing apparatus (200) and an electronic device (500). The fingerprint sensing apparatus (200) comprises a sensor unit (22) and a detection unit (24), wherein the sensor unit (22) comprises multiple first electrodes (222) and multiple second electrodes (224), and the multiple first electrodes (222) and the multiple second electrodes (224) are insulated from each other and are arranged in an intersecting manner; and the detection unit (24) comprises: a plurality of first switches (S1) which are connected to the multiple first electrodes (222) in one-to-one correspondence; a control circuit (242) which is used for controlling the cut-off time sequence of the plurality of first switches (S1); a reference circuit (240) which is selectively connected to the multiple first electrodes (222) by means of the plurality of first switches (S1), and the reference circuit (240) is used for providing a pre-set reference voltage (Vp) for the multiple first electrodes (222); and a signal reading circuit (244) which is used for providing an excitation signal (Vref) for the multiple second electrodes (224), and receiving a sensing signal (Vd) output by the second electrodes (224) so as to acquire fingerprint information. The electronic device (500) comprises the fingerprint sensing apparatus (200) above.

Description

Fingerprint sensing device and electronic device

Technical field

The utility model relates to a fingerprint sensing device and an electronic device.

Background technique

At present, fingerprint sensing devices are gradually gaining popularity. However, the cost of the fingerprint sensing device is still high.

Utility model content

The embodiments of the present invention aim to at least solve one of the technical problems existing in the prior art. To this end, the embodiments of the present invention need to provide a fingerprint sensing device and an electronic device.

The utility model provides a fingerprint sensing device, comprising:

a sensor unit comprising a plurality of first electrodes and a plurality of second electrodes, wherein the plurality of first electrodes and the plurality of second electrodes are insulated and arranged in an intersecting manner;

a detecting unit, configured to drive the sensor unit to perform fingerprint sensing, where the detecting unit comprises:

a plurality of first switches connected in one-to-one correspondence with the plurality of first electrodes;

a control circuit for controlling a turn-off timing of the plurality of first switches;

a reference circuit, selectively connectable to the plurality of first electrodes by the plurality of first switches, the reference circuit for providing a predetermined reference voltage to the plurality of first electrodes;

The signal reading circuit is configured to provide an excitation signal to the plurality of second electrodes and receive a sensing signal from the output of the second electrode to obtain fingerprint information.

In contrast, the existing fingerprint sensing device includes a plurality of rectangular block electrodes, the plurality of rectangular block electrodes are coplanar with each other, spaced apart from each other, arranged in a matrix, and each rectangular block electrode is connected to each other through a wire Detection circuit. Each of the block electrodes corresponds to a sensing pixel.

As can be seen by comparison, since the fingerprint sensing device of the present application includes the plurality of first electrodes and the plurality of second electrodes, and the plurality of first electrodes and the plurality of second electrodes are insulated and intersected, Each of the intersections correspondingly forms a sensing pixel. Therefore, compared with the above existing fingerprint sensing device, the fingerprint sensing device of the present application ensures that the sensing pixel is sufficient, the plurality of The number of wires connecting the first electrode and the plurality of second electrodes to the detecting unit is reduced, thereby reducing the cost of the fingerprint sensing device.

In addition, since the number of wires is reduced, the fingerprint sensing device can also be developed toward miniaturization.

In some embodiments, when the signal reading circuit provides the excitation signal to perform sensing on the plurality of second electrodes, the control circuit controls the plurality of first switches to be sequentially turned off, such that The plurality of first electrodes are suspended in sequence, and the reference circuit supplies the predetermined reference voltage signal to the unsuspended first electrode through the closed first switch.

In some embodiments, at the same time, the control circuit only controls one of the first switches to open, and controls the remaining first switches to be off.

In some embodiments, the detecting unit further includes a plurality of second switches and a plurality of the signal reading circuits, wherein the plurality of second switches are connected in one-to-one correspondence with the plurality of second electrodes, wherein The number of the plurality of second switches is greater than the number of the plurality of signal reading circuits, and each of the plurality of signal reading circuits is connected to at least two second switches And for time-division driving to operate with the second electrode connected to the at least two second switches.

In some embodiments, the control circuit is further configured to control whether the plurality of second switches are turned on or off.

In some embodiments, the plurality of first electrodes are closer to a user's finger than the plurality of second electrodes.

In some embodiments, the sensor unit further includes an insulating substrate and an insulating layer, the plurality of second electrodes are disposed on the insulating substrate, and the insulating layer is disposed on the plurality of second electrodes. The plurality of first electrodes are disposed on the insulating layer, wherein a side of the plurality of first electrodes facing away from the plurality of second electrodes is for receiving a contact or proximity input of a user's finger.

In some embodiments, the detecting unit further includes a modulating unit configured to output a modulated signal to the detecting unit, wherein the excitation signal and the predetermined reference voltage signal are both modulated by the modulated signal signal.

In some embodiments, the signal reading circuit includes an amplifier and a feedback branch, wherein the amplifier includes an in-phase terminal, an inverting terminal, an output terminal, and a ground terminal, and the feedback branch is coupled to the opposite The inverting terminal is further configured to be coupled to the second electrode, the inverting terminal is configured to receive the excitation signal, and the ground terminal is configured to receive the modulation signal.

The present invention also provides an electronic device comprising the fingerprint sensing device of any of the above.

Since the electronic device includes the fingerprint sensing device, the cost of the electronic device Lower.

The additional aspects and advantages of the embodiments of the invention will be set forth in part in the description in the written description

DRAWINGS

The above and/or additional aspects and advantages of the embodiments of the invention will be apparent from the

1 is a schematic structural view of a conventional fingerprint sensing device;

2 is a circuit block diagram of a fingerprint sensing device according to an embodiment of the present invention;

3 is a schematic structural view of an embodiment of the sensor unit of FIG. 2;

4 is a schematic structural view of another embodiment of the sensor unit of FIG. 2;

5 is a schematic cross-sectional view of a fingerprint sensing device according to an embodiment of the present invention;

6 is a schematic diagram showing a connection structure between a first electrode and a second electrode, a detecting unit, and a modulating unit in a fingerprint sensing device according to an embodiment of the present invention;

7 is a schematic diagram showing a connection structure of a first electrode and a second electrode corresponding to a reference circuit and a signal reading circuit in the fingerprint sensing device according to an embodiment of the present invention;

8 is a schematic diagram of an equivalent circuit of a fingerprint sensing device performing capacitance sensing according to an embodiment of the present invention;

9 is a schematic plan view of an electronic device according to an embodiment of the present invention.

detailed description

The embodiments of the present invention are described in detail below, and the examples of the embodiments are illustrated in the drawings, wherein the same or similar reference numerals are used to refer to the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are intended to be illustrative of the invention and are not to be construed as limiting.

In the description of the present invention, it is to be understood that the terms "first" and "second" are used for descriptive purposes only and are not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated. . Thus, features defining "first" or "second" may include one or more of the described features either explicitly or implicitly. In the description of the present invention, the meaning of "a plurality" is two or more unless specifically and specifically defined otherwise.

In the description of the present invention, it should be noted that the terms "installation", "connected", and "connected" are to be understood broadly, and may be, for example, a fixed connection or a Disassembling the connection, or connecting integrally; may be mechanical connection, electrical connection or communication with each other; may be directly connected, or may be indirectly connected through an intermediate medium, may be internal communication of two elements or mutual interaction of two elements Role relationship. For those skilled in the art, the specific meanings of the above terms in the present invention can be understood on a case-by-case basis.

The following disclosure provides many different embodiments or examples for implementing different structures of the present invention. In order to simplify the disclosure of the present invention, the components and settings of the specific examples are described below. Of course, they are merely examples and are not intended to limit the invention. In addition, the present invention may repeat reference numerals and/or reference numerals in different examples, which are for the purpose of simplicity and clarity, and do not in themselves indicate the relationship between the various embodiments and/or settings discussed. Moreover, the present invention provides examples of various specific processes and materials, but one of ordinary skill in the art will recognize the use of other processes and/or the use of other materials.

Further, the described features, structures may be combined in one or more embodiments in any suitable manner. In the following description, numerous specific details are set forth However, those skilled in the art will appreciate that the technical solution of the present invention may be practiced without one or more of the specific details or other structures, components, and the like. In other instances, well-known structures or operations are not shown or described in detail to avoid obscuring the invention.

Please refer to FIG. 1. FIG. 1 is a schematic structural diagram of a conventional fingerprint sensing device. The fingerprint sensing device 100 includes a substrate 10, a plurality of sensing electrodes 12, and a detection circuit 16. The plurality of sensing electrodes 12 are formed on the substrate 10, and the plurality of sensing electrodes 12 are arranged in a two-dimensional array, that is, the sensing array 14 is formed. The plurality of sensing electrodes 12 are coplanar with each other, and each sensing electrode 12 forms a sensing pixel. The detection circuit 16 is formed on the substrate 10 at the periphery of the sensing array 14. The detecting circuit 16 is electrically connected to each sensing electrode 12 for providing an excitation signal to each sensing electrode 12, and driving each sensing electrode 12 to perform a sensing operation. Further, the detecting circuit 16 receives the sensing signal output from the sensing electrode 12, and acquires fingerprint information according to the sensing signal.

However, since the detecting circuit 16 is electrically connected to each of the sensing electrodes 12, for example, by wires, if the number of sensing electrodes 12 is large, the arrangement of the wires will be greatly increased. Difficulty, thereby increasing the manufacturing cost of the fingerprint sensing device 100. In addition, in order to meet the electrical requirements, the wires and the wires must have a certain interval. Therefore, the more wires are arranged, the larger the size of the fingerprint sensing device 100 is to ensure the yield of the fingerprint sensing device 100, thereby being disadvantageous. The miniaturization of the fingerprint sensing device 100 has progressed.

In particular, when the fingerprint sensing device 100 is, for example, a small-sized fingerprint sensing module, the above technical problems are more prominent. Generally, a small-sized fingerprint sensing module is disposed, for example, in a non-display area of a mobile terminal, for example, at a location of a Home button, at a back side of a mobile terminal, and at a side. However, the fingerprint sensing module can also be disposed in, for example, a display area of the mobile terminal. The display area is an area where the mobile terminal displays an image.

In order to solve at least one of the above technical problems, the present invention proposes a new fingerprint sensing device 200. 2 and FIG. 3, FIG. 2 is a circuit block diagram of the fingerprint sensing device 200 of the present invention, and FIG. 3 is a schematic structural view of an embodiment of the sensor unit of the fingerprint sensing device 200 of FIG. The fingerprint sensing device 200 can be used to perform fingerprint information sensing. The fingerprint sensing device 200 includes a sensor unit 22 and a detecting unit 24.

The sensor unit 22 includes a plurality of first electrodes 222 and a plurality of second electrodes 224. The plurality of first electrodes 222 and the plurality of second electrodes 224 are insulated and arranged in a cross.

The detecting unit 24 is configured to provide an excitation signal Vref to the plurality of second electrodes 224, and control the plurality of first electrodes 222 to be suspended, and provide a predetermined reference voltage signal Vp to the first electrode that is not suspended. 222. The sensor unit 22 is driven to perform fingerprint information sensing.

Since the fingerprint sensing device 200 of the present application includes the plurality of first electrodes 222 and the plurality of second electrodes 224, and the plurality of first electrodes 222 and the plurality of second electrodes 224 are insulated and intersected, each An intersection is formed to form a sensing pixel. Therefore, compared with the above-mentioned conventional fingerprint sensing device, the fingerprint sensing device 200 of the present application ensures that the sensing pixel is sufficiently large. The number of wires to which the first electrode 222 and the plurality of second electrodes 224 are connected to the detecting unit 24 is reduced, so that the cost of the fingerprint sensing device 200 can be reduced.

Further, since the number of wires is reduced, the fingerprint sensing device 200 can also be developed toward miniaturization.

When the fingerprint sensing device 200 performs fingerprint information sensing, the detecting unit 24 controls the remaining first electrode 222 to control the remaining first electrode 222 to receive the predetermined reference voltage signal Vp.

The detecting unit 24 further receives the sensing signal Vd output from the second electrode 224 to acquire fingerprint image information.

When the user's finger approaches the fingerprint sensing device 200, the plurality of first electrodes 222 are closer to the user's finger than the plurality of second electrodes 224, and the plurality of first electrodes 222 are used for Capacitively coupled to finger 400 (see Figure 6). The fingerprint sensing device 200 is configured to sense fingerprint image information of the finger 400.

The detecting unit 24 causes the first electrode 222 to be suspended by disconnecting the first electrode 222. When the detecting unit 24 is disconnected from a first electrode 222, it is electrically reconnected with the previously disconnected first electrode 222.

In some embodiments, the plurality of first electrodes 222 are spaced apart in the first direction, and each of the first electrodes 222 extends in the second direction. The plurality of second electrodes 224 are spaced apart in the second direction, and each of the second electrodes 224 extends in the first direction. The first direction is different from the second direction. The first direction and the second direction are, for example but not limited to, a vertical relationship. As shown in FIG. 3, in the present embodiment, the first electrode 222 is arranged as a row electrode in the Y direction, that is, the first row, the second row, the third row, the mth row, where m is A natural number greater than 1. The second electrode 224 is a column electrode and is sequentially arranged in the X direction, that is, the first column, the second column, the third column, the nth column, where n is a natural number greater than 1. The intersection area between the plurality of first electrodes 222 and the plurality of second electrodes 224 forms a second coupling capacitor CF, that is, the fingerprint sensing device 200 can be formed with m*n second coupling capacitors CF (see FIG. 6). ). Alternatively, the first direction and the second direction may be set, for example, at a certain angle, for example, 45°, 60°, or the like. In this embodiment, the plurality of first electrodes 222 and the plurality of second electrodes 224 have a rectangular strip shape. However, the plurality of first electrodes 222 and the plurality of second electrodes are variably 224 may also take other suitable shapes, such as curved strips and the like.

Please refer to FIG. 4. FIG. 4 is a schematic structural diagram of another embodiment of the sensor unit 22. The plurality of first electrodes 222 are spaced apart along the first direction, and each of the first electrodes 222 includes a plurality of first sub-electrodes 222a and a wire 222b connecting the adjacent first sub-electrodes 222a. The plurality of second electrodes 224 are spaced apart in the second direction, and each of the second electrodes 224 includes a plurality of second sub-electrodes 224a and a wire 224b connecting the adjacent second sub-electrodes 224a. The first direction and the second direction are different, such as, but not limited to, a vertical relationship. As shown in FIG. 4, the first electrode 222 is arranged as a row electrode in the Y direction, for example, the first row, the second row, the third row, the seventh row, and the second electrode 224 serves as a column electrode in the X direction. Arrange sequentially, for example, column 1, column 2, column 3, column 8. First electrode 222 The intersection region between the second electrode 224 and the second electrode 224 forms a second coupling capacitance CF (see FIG. 6). Therefore, the sensor unit 22 shown in FIG. 4 can be formed with 7*8=56 second coupling capacitors CF. It should be noted that the number 56 here is only an example, and the number of actual products is more or less than 56, and the manufacturer can set according to the product requirements. Alternatively, the first direction and the second direction may be set, for example, at a certain angle, for example, 45°, 60°, or the like. In the present embodiment, the first electrode 222 and the second electrode 224 are in the shape of a rectangular block. However, the present application is not limited thereto, and the first electrode 222 and the second electrode 224 may also have other suitable shapes. . The lengths of the first electrode 222 and the second electrode 224 shown in FIG. 4 become shorter than those of the first electrode 222 and the second electrode 224 shown in FIG.

It can be understood that the structure of the first electrode 222 and the structure of the second electrode 224 in the above embodiments may be variously combined and deformed as long as the first electrode 222 and the second electrode 224 are disposed in an insulated intersection.

The first electrode 222 and the second electrode 224 may be made of, for example, a transparent conductive material such as an indium tin oxide (ITO) material, an indium zinc oxide (IZO) material, or the like. However, the first electrode 222 and the second electrode 224 may also be made of other suitable electrically conductive materials, such as metal materials, alloy materials, and the like. Since the first electrode 222 and the second electrode 224 are both conductive electrodes, electrical isolation is performed between the first electrode 222 and the second electrode 224 by providing an insulating material.

Referring to FIG. 2 again, in some embodiments, the fingerprint sensing device 200 may further include a modulating unit 26 for generating a modulated signal M and outputting the modulated signal M to the detecting unit 24.

Optionally, the signals in the detecting unit 24 are all signals modulated by the modulation signal M. For example, the excitation signal Vref and the predetermined reference voltage signal Vp are both signals modulated by the modulation signal M. However, the detection unit 24 may also be a partial signal that is modulated by the modulation signal M. For example, the excitation signal Vref is a signal modulated by the modulation signal M. The predetermined reference voltage signal Vp is a constant voltage signal.

Since the excitation signal Vref is a signal modulated by the modulation signal M, the signal-to-noise ratio of the fingerprint sensing device 200 can be improved, thereby improving the sensing accuracy of the fingerprint sensing device 200.

In some embodiments, the excitation signal Vref varies as the modulation signal M changes. For example, the excitation signal Vref rises as the modulation signal M increases, with the adjustment The signal M is lowered and lowered.

In some embodiments, the modulating unit 26 outputs the modulation signal M to the ground terminal c (see FIG. 8) of the detecting unit 24 as a ground signal of the detecting unit 24, for example. The ground signal corresponds to a varying signal. Correspondingly, the electrical signals of the detecting unit 24 use the changed ground signal as a voltage reference signal. When the local signal changes, the electrical signal in the detecting unit 24 changes with the change of the ground signal. Thus, all signals of the detecting unit 24 are signals modulated by the modulation signal M.

Alternatively, in other embodiments, the modulating unit 26 may also output the modulation signal M to the power terminal d (see FIG. 8) or the reference power terminal (not shown) of the detecting unit 24, and may also achieve detection. The effect of modulation of all signals in unit 24 is performed.

Since all the signals in the detecting unit 24 are the signals modulated by the modulation signal M, the signals on the plurality of first electrodes 222 and the plurality of second electrodes 224 are all modulated signals. The M-modulated signal can thereby reduce the adverse effects of lateral parasitic capacitance between adjacent first electrodes 222, lateral parasitic capacitance between adjacent second electrodes 224, and the like. In addition, the signal-to-noise ratio of the excitation signal Vref can be increased, thereby improving the signal-to-noise ratio of the sensing signal Vd, thereby further improving the sensing accuracy of the fingerprint sensing device 200.

It should be noted that, in some modified embodiments, the fingerprint sensing device 200 may also omit the modulation unit 26. Correspondingly, the ground of the detection unit 24 is for example loaded with a constant 0 volt signal. The following description is mainly made by taking the modulation technology of the fingerprint sensing device 200 as an example.

Please refer to FIG. 5. FIG. 5 is a schematic cross-sectional view of the fingerprint sensing device 200 of the present application. In some embodiments, the sensor unit 22 described above may further include a substrate 220 and an insulating layer 226. The plurality of second electrodes 224 are disposed on the substrate 220, the insulating layer 226 is disposed on the plurality of second electrodes 224, and the plurality of first electrodes 222 are disposed on the insulating layer 226. The side of the plurality of first electrodes 222 facing away from the plurality of second electrodes 224 is for receiving a contact or proximity input of a user's finger. The area where the first electrode 222 and the second electrode 224 are defined is the sensing area I, and the area on the defining substrate 220 around the sensing area I is the non-sensing area II. Optionally, the detecting unit 24 and the modulating unit 26 are located in the non-sensing area II of the substrate 220. Alternatively, the detecting unit 24 and the modulating unit 26 may be connected to the substrate 220 through a connecting member such as a flexible circuit board, and the detecting unit 24 and the modulating unit 26 are not limited to be disposed on the substrate 220.

The substrate 220 is an insulating substrate, and is, for example, a suitable substrate such as a glass substrate or a film substrate.

In some embodiments, the detecting unit 24 is integrated into a sensing chip, for example, by a silicon process, and the modulation unit 26 is integrated into a control chip, for example, by a silicon process. Of course, the detecting unit 24 and the modulating unit 26 are not limited to be integrated on one chip, and may be integrated on several chips, for example, two or three, as appropriate. The sensing chip and the control chip are bonded to the substrate 220 by way of a chip on glass (COG) or a chip on film (COF). The detection unit 24 and the modulation unit 26 are further connected to an external circuit (not shown), for example, by a suitable connector such as a flexible circuit board.

Since the sensor unit 22 of the present application forms the first electrode 222 and the second electrode 224 on the insulating substrate 220, the present application includes the sensor unit compared to the sensor unit that forms the sensing electrode on the silicon substrate. The manufacturing cost of the fingerprint sensing device 200 of 22 is further reduced.

Referring to FIG. 5 again, in some embodiments, the sensor unit 22 described above may further include a protective layer 228. The protective layer 228 is disposed on the plurality of first electrodes 222 and the insulating layer 266 to prevent the first electrode 222 from directly contacting the outside to damage the first electrode 222, thereby affecting the sensing effect. However, the protective layer 228 may also be omitted in other embodiments. In addition, for example, when the fingerprint sensing device 200 is a small-sized fingerprint sensing module, the protective layer 228 may also be replaced with a package, and the sensor unit 22, the sensing chip, and the control chip are encapsulated in the Between the package and the substrate 220. The package is used to cover the sensor unit 22, the sensing chip and the control chip, and fill the gap between the sensor unit 22, the sensing chip and the control chip. The package is, for example but not limited to, made of a material such as an epoxy resin.

Referring to FIG. 5 and FIG. 6 together, FIG. 6 is a schematic diagram of a connection structure between the first electrode 222 and the second electrode 224 and the detecting unit 24 and the modulating unit 26. When the finger 400 contacts the sensing region I of the fingerprint sensing device 200, the first coupling capacitor CS is formed between the finger 400 and the plurality of first electrodes 222. In addition, a plurality of second coupling capacitors CF are formed between the plurality of first electrodes 222 and the plurality of second electrodes 224. The first coupling capacitor CS formed between the suspended first electrode 222 and the finger 400 is connected in series with the second coupling capacitor CF between the detecting unit 24 and the ground. In contrast, the unsuspended first electrode 222 functions as a shield electrode due to receiving the predetermined reference voltage signal Vp, and correspondingly, a first coupling formed between the unsuspended first electrode 222 and the finger 400 The combined capacitance CS is shielded from being detected by the detecting unit 24. Therefore, the first coupling capacitance CS formed between the finger 400 and the suspended first electrode 222 is critical to the detection unit 24 acquiring the sensing information and can be detected by the detecting unit 24.

Generally, the human body is connected to the earth. Correspondingly, the first coupling capacitor CS and the second coupling capacitor CF are connected in series between the detecting unit 24 and the ground.

It should be noted that in the present application, the word "contact" includes both direct touch and proximity.

In some embodiments, the detection unit 24 includes a reference circuit 240, a plurality of first switches S1, and a control circuit 242. The reference circuit 240 is connected to the plurality of first electrodes 222 in a one-to-one correspondence by the plurality of first switches S1. The reference circuit 240 is configured to provide the predetermined reference voltage signal Vp to the plurality of first electrodes 222. The control circuit 242 is connected to the plurality of first switches S1 for controlling the plurality of first switches S1 to be opened or closed. It should be noted that, in FIG. 6, since only one first electrode 222 is shown, correspondingly, only one first switch S1 is shown.

The detecting unit 24 controls the plurality of first switches S1 to be sequentially turned off by the control circuit 242 to control the plurality of first electrodes 222 to be suspended in sequence.

When the fingerprint sensing device 200 performs sensing, after the control circuit 242 controls the first switch S1 to be turned off for a predetermined time, the first switch S1 that is currently turned off is closed, and the other switch is turned off again. The first switch S1. Therefore, the plurality of first switches S1 are sequentially disconnected, so that the plurality of first electrodes 222 are suspended in order, thereby implementing a sensing operation.

In some embodiments, the predetermined reference voltage signal Vp is a signal modulated by the modulated signal M by a constant voltage signal. However, the predetermined reference voltage signal Vp can also be a constant voltage signal. Wherein, when the predetermined reference voltage signal Vp is a constant voltage signal, the reference circuit 240 is preferably disposed in the control chip instead of the sensing chip. The reference circuit 240 is referenced to the voltage in the control chip as a system or device. The signal on the system ground or device ground is typically a constant voltage signal of 0 volts.

In some embodiments, the first switch S1 can be a thin film transistor switch. For example, amorphous silicon thin film transistor switches, low temperature polysilicon thin film transistor switches, high temperature polysilicon thin film transistor switches, metal oxide thin film transistor switches, and the like. The metal oxide thin film transistor switch is an indium gallium zinc oxide (IGZO) thin film transistor switch. Correspondingly, the gate is a control electrode for controlling the on/off of the switch; the source is the first transmission electrode and is connected to the reference circuit 240; the drain is the second transmission The pole is connected to the first electrode 222. However, in other embodiments, the first switch S1 may also be other suitable types of switches, such as a bipolar transistor switch. Of course, the first switch S1 can also be an electromagnetic switch, such as a relay or the like. For example, when the first switch S1 is a suitable type of switch such as a thin film transistor, the plurality of first switches S1 may be formed directly on the substrate 220, thereby reducing manufacturing costs.

Referring to FIG. 6 again, in some embodiments, the detecting unit 24 may further include a plurality of signal reading circuits 244 for connecting with the plurality of second electrodes 222. The excitation signal Vref is supplied to the plurality of second electrodes 224, and the sensing signals Vd output by the plurality of second electrodes 224 are received to obtain sensing information. In the embodiment, the number of the plurality of signal reading circuits 244 is equal to the number of the second electrodes 224, and the plurality of signal reading circuits 244 are connected in one-to-one correspondence with the plurality of second electrodes 224. The plurality of signal reading circuits 244 can simultaneously output the excitation signal Vref to all of the second electrodes 222, and simultaneously read all of the sensing signals Vd outputted by the second electrodes 224.

It should be noted that, in FIG. 6, since only one second electrode 224 is shown, only one signal reading circuit 244 is shown in the detecting unit 24 for clarity. However, in practice, each of the second electrodes 224 is respectively connected to a signal reading circuit 244.

Alternatively, in other embodiments, the number of the plurality of signal reading circuits 244 is less than the number of the plurality of second electrodes 224. Accordingly, at least some or all of the signal reading circuits 244 are multiplexed, and the second electrodes 224 located at different positions are time-divisionally driven to operate.

In some variant embodiments, as shown in FIG. 7, the detection unit 24 may further include a plurality of second switches S2. The plurality of second switches S2 are connected to the plurality of second electrodes 224 in one-to-one correspondence. The control circuit 242 is connected to the plurality of second switches S2 for controlling the plurality of second switches S2 to be opened or closed. The number of the plurality of signal reading circuits 244 is less than the number of the plurality of second switches S2. At least part or all of the signal reading circuit 244 is respectively connected to at least two second switches S2, and the signal reading circuit 244 connecting at least two second switches S2 drives the second electrodes 224 respectively connected to the at least two second switches S2. .

In the embodiment shown in FIG. 7, the number of the plurality of second switches S2 is twice that of the plurality of signal reading circuits 244, and each of the signal reading circuits 244 is connected to the two second switches S2. Correspondingly, the control circuit 242, for example, simultaneously controls half of the second switches S2 to be closed at the same time, and all of the signal reading circuits 244 simultaneously drive one through a half of the closed second switches S2. The second second electrode 224 operates, and by a plurality of switching, the plurality of signal reading circuits 244 drive all of the second electrodes 224 to perform a complete detection. As such, the number of the plurality of signal reading circuits 244 is greatly reduced by time division multiplexing, thereby reducing the manufacturing cost of the fingerprint sensing device 200.

In operation, when the detecting unit 24 sequentially disconnects the plurality of first electrodes 222, the plurality of signal reading circuits 244 are electrically connected to the plurality of second electrodes 224 in a time division manner. The opening or closing of the second switch S2 is controlled by the control circuit 242, so that the plurality of signal reading circuits 244 perform time-divisional reading of the sensing signal Vd output by the second electrode 224. As shown in FIG. 7, each of the signal reading circuits 244 is connected to two second switches S2, taking the first signal reading circuit 244 located on the left side as an example. When the sensing signal Vd is read, The control circuit 242 first controls a second switch S2a connected to the signal reading circuit 244 and located on the left side to be closed, and controls the second switch S2b located on the right side to be disconnected; the second switch S2a to be disconnected After the sensing signal Vd of the connected second electrode 224 is read, the second circuit S2b connected to the control circuit 242 and the control signal reading circuit 244 is closed, and the second switch S2a is turned off to read The sensing signal Vd of the second electrode 224 to which the second switch S2b is connected.

It should be noted that, for clarity, the two second switches S2 connected to the first signal reading circuit 244 on the left side are denoted here as S2a and S2b, respectively.

For another example, the number of the plurality of second switches S2 is three times that of the plurality of signal reading circuits 244, and each of the signal reading circuits 244 is connected to three second switches S2, and accordingly, all signals are read. The circuit 244 simultaneously drives one-third of the second electrode 224 to operate at a time. By three switchings, the plurality of signal reading circuits 244 drive all of the second electrodes 224 to perform a complete detection. The foregoing description of the number of signal reading circuits 244 is merely illustrative. However, the present application is not limited thereto, and the manufacturer may correspondingly set a corresponding number of signal reading circuits 244 according to product specifications and product quality requirements.

When the plurality of second switches S2 are, for example, suitable switches of a thin film transistor or the like, the plurality of second switches S2 may also be disposed on the substrate 220.

Referring to FIG. 6 and FIG. 7 together, the control circuit 242 controls the first switch S1 to be turned off, for example, row by row. However, the control circuit 242 can also control the first switch S1 to be disconnected by interlacing. For example, the control circuit 242 first controls the first switch S1 located in the odd row to be disconnected one by one, and then controls the even row. A switch S1 is disconnected one by one. The control circuit 242 controls the plurality of first The turn-off timing of the switch S1 is not in the manner enumerated herein, as long as the control circuit 242 controls the current first switch S1 to be turned off, and controls the first open first switch S1 to be closed, operating in such a control manner. This way of controlling all of the first switches S1 to be sequentially turned off should fall within the scope of protection of the present application.

The reference circuit 240 of FIG. 7 has an output terminal (not shown) for outputting a predetermined reference voltage signal, and the output terminal is respectively connected to the plurality of first switches S1, thereby reducing the manufacturing cost of the capacitive sensing device 200. Alternatively, a plurality of reference circuits may be provided, each reference circuit correspondingly outputs a predetermined reference voltage signal, and each reference signal source is connected in one-to-one correspondence with the plurality of first switches S1. Still alternatively, the reference circuit 240 includes a plurality of outputs coupled to the plurality of first switches S1.

Referring to Figures 7 and 8, together, in some embodiments, the signal reading circuit 244 includes an amplifier Q and a feedback branch F. The amplifier Q includes an in-phase terminal a, an inverting terminal b, a ground terminal c, a power terminal d, and an output terminal Vout, and the feedback branch F is connected to the inverting terminal b and the output terminal Vout. The inverting terminal b is further connected to the second electrode 224 through the second switch S2. The non-inverting terminal a is for receiving the excitation signal Vref. The ground terminal c is used to load the modulation signal M. The power terminal d is used to load a power voltage. The feedback branch F includes a feedback capacitor CB and a third switch S3. The feedback capacitor CB and the third switch S3 are connected in parallel between the inverting terminal b and the output terminal Vout.

In operation, the amplifier Q is in a virtual short state, and the voltages of the non-inverting terminal a and the inverting terminal are the same. Correspondingly, the excitation signal Vref is sequentially output to the second electrode 224 through the non-inverting terminal a, the inverting terminal b, and the closed second switch S2. At the same time, the control circuit 242 (see FIG. 6) controls the plurality of first switches S1 to be sequentially turned off, and the reference circuit 240 supplies a predetermined reference voltage signal Vp to the first electrode 222 through the closed first switch S1. For example, when there is a finger 400 (see FIG. 6) approaching the suspended first electrode 222, since the first coupling capacitance CS formed between the finger 400 and the suspended first electrode 222 is connected in series with the second coupling capacitor CF, the signal is read. The first electrode 222 that is not suspended is used as the shield electrode between the circuit 244 and the ground. Therefore, the plurality of second electrodes 224 have different signals corresponding to the output of the sensing signal Vd. The second electrode 224 is configured to output a corresponding sensing signal Vd to the output terminal Vout through the feedback branch F. Thereby, the detecting unit 24 can acquire corresponding fingerprint image information according to the sensing signal Vd output by the plurality of second electrodes 224.

It should be noted that when the capacitive sensing device 200 performs fingerprint sensing, for example, The fingerprint of the finger 400 includes a ridge and a valley. Therefore, the capacitance value of the first coupling capacitor CS formed between the ridge and the suspended first electrode 222 is greater than the capacitance value of the first coupling capacitor CS formed between the valley and the suspended first electrode 222. .

The signal reading circuit 244 is not limited to the circuit shown in FIG. 8 of the present application, and may be other suitable types of circuits as long as the excitation signal Vref is transmitted to the second electrode 224 and the output from the second electrode 224 is received. The sensing signal Vd falls within the scope of protection of the present application.

In addition, the detecting unit 24 of the present application may further add a circuit such as a filter circuit, an amplifying circuit, an analog-to-digital conversion circuit, and the like after the output terminal Vout.

Please refer to FIG. 9. FIG. 9 is a schematic structural diagram of an embodiment of an electronic device according to the present application. The electronic device 500 is, for example but not limited to, any suitable type of product such as a consumer electronics product, a home electronics product, a vehicle-mounted electronic product, or a wearable electronic product. Among them, consumer electronic products such as mobile phones, tablets, notebook computers, desktop monitors, computer integrated machines and other suitable electronic products. Home-based electronic products such as smart door locks, televisions, refrigerators and other suitable electronic products. The vehicle-mounted electronic products are, for example, various suitable electronic products such as car navigation systems and car DVDs. Wearable electronic products such as watches, bracelets, rings and other suitable electronic products.

The electronic device 500 includes the fingerprint sensing device 200 of any of the above embodiments.

In some embodiments, the electronic device 500 can further include a display area 501 and a non-display area 502. The electronic device 500 is configured to display a display screen corresponding to the display area 501 for displaying a screen or the like. The non-display area 502 is located around the display area 501. Generally, the front surface of the electronic device 500 includes a protective cover 503.

The fingerprint sensing device 200 is, for example, a small-sized fingerprint sensing module, and is disposed in the non-display area 502 of the electronic device 500, for example, at a position corresponding to the Home button. Specifically, the fingerprint sensing device 200 can be hidden under the protective cover 503. Alternatively, the fingerprint sensing device 200 can also be exposed at a through hole of the protective cover 503. In addition, the fingerprint sensing device 200 may be disposed at an appropriate position such as a side surface or a back surface of the electronic device 500.

Further, when the fingerprint sensing device 200 is a fingerprint sensing module, the fingerprint sensing device 200 can also be located in the display area 501, for example, the sensor unit 22 of the fingerprint sensing device 200 (see FIG. 3). ) is located in a partial area of the display area 501.

It should be noted that when the fingerprint sensing device 200 is a fingerprint sensing module, the fingerprint sensing module can also perform touch sensing.

The sensor unit 22 (see FIG. 3) of the fingerprint sensing device 200 can also be located in the entire area of the display area 501. Optionally, the fingerprint sensing device 200 performs touch sensing and fingerprint image information sensing. For example, the fingerprint sensing device 200 is configured to perform touch sensing, and a local region is used to perform fingerprint image information sensing. For another example, the fingerprint sensing device 200 can also perform touch sensing and fingerprint image information sensing and the like in a time-sharing manner. Thus, the electronic device 500 can perform fingerprint image information sensing in full screen.

In the description of the present specification, the description with reference to the terms "one embodiment", "some embodiments", "illustrative embodiment", "example", "specific example", or "some examples", etc. The specific features, structures, materials or characteristics described in the embodiments or examples are included in at least one embodiment or example of the invention. In the present specification, the schematic representation of the above terms does not necessarily mean the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in a suitable manner in any one or more embodiments or examples.

While the embodiments of the present invention have been shown and described above, it is understood that the foregoing embodiments are illustrative and are not to be construed as limiting the scope of the invention Variations, modifications, substitutions and variations of the embodiments described above are possible.

Claims

A fingerprint sensing device comprising:

a sensor unit comprising a plurality of first electrodes and a plurality of second electrodes, wherein the plurality of first electrodes and the plurality of second electrodes are insulated and arranged in an intersecting manner;

a detecting unit, configured to drive the sensor unit to perform fingerprint sensing, where the detecting unit comprises:

a plurality of first switches connected in one-to-one correspondence with the plurality of first electrodes;

a control circuit for controlling a turn-off timing of the plurality of first switches;

a reference circuit, selectively connectable to the plurality of first electrodes by the plurality of first switches, the reference circuit for providing a predetermined reference voltage to the plurality of first electrodes;

The signal reading circuit is configured to provide an excitation signal to the plurality of second electrodes and receive a sensing signal from the output of the second electrode to obtain fingerprint information.
The fingerprint sensing device according to claim 1, wherein said control circuit controls said plurality of signals when said signal reading circuit supplies said excitation signal to said plurality of second electrodes for performing sensing The first switch is sequentially turned off such that the plurality of first electrodes are suspended in sequence, and the reference circuit supplies the predetermined reference voltage signal to the unsuspended first electrode through the closed first switch.
The fingerprint sensing device according to claim 2, wherein at the same time, the control circuit controls only one of the first switches to be turned off, and controls the remaining first switches to be turned off.
The fingerprint sensing device according to claim 2, wherein said detecting unit further comprises a plurality of second switches and said plurality of signal reading circuits, said plurality of second switches and said plurality of Two electrodes are connected in one-to-one correspondence, wherein the number of the plurality of second switches is greater than the number of the plurality of signal reading circuits, and each of the plurality of signal reading circuits reads The circuit is connected to at least two second switches for time-division driving to operate with the second electrode connected to the at least two second switches.
The fingerprint sensing device according to claim 4, wherein the control circuit is further configured to control whether the plurality of second switches are turned on or off.
The fingerprint sensing device according to any one of claims 1 to 5, wherein the plurality of first electrodes are closer to a user's finger than the plurality of second electrodes.
The fingerprint sensing device according to any one of claims 1 to 5, wherein the sensor unit further comprises an insulating substrate and an insulating layer, and the plurality of second electrodes are disposed in the On the edge substrate, the insulating layer is disposed on the plurality of second electrodes, and the plurality of first electrodes are disposed on the insulating layer, wherein the plurality of first electrodes are opposite to the plurality of strips One side of the two electrodes is used to receive a contact or proximity input of a user's finger.
The fingerprint sensing device according to any one of claims 1 to 5, wherein the detecting unit further comprises a modulating unit for outputting a modulated signal to the detecting unit, the excitation signal and the The predetermined reference voltage signal is a signal modulated by the modulated signal.
A fingerprint sensing device according to claim 8 wherein said signal reading circuit comprises an amplifier and a feedback branch, wherein said amplifier comprises an in-phase terminal, an inverting terminal, an output terminal, and a ground terminal. The feedback branch is connected between the inverting end and the output end, the inverting end is further configured to be connected to the second electrode, the non-inverting end is configured to receive the excitation signal, and the grounding end is used Receiving the modulated signal.
An electronic device comprising the fingerprint sensing device of any of claims 1-9.