CN104217193B - Capacitive fingerprint sensor circuit and inductor - Google Patents
Capacitive fingerprint sensor circuit and inductor Download PDFInfo
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- CN104217193B CN104217193B CN201410105847.6A CN201410105847A CN104217193B CN 104217193 B CN104217193 B CN 104217193B CN 201410105847 A CN201410105847 A CN 201410105847A CN 104217193 B CN104217193 B CN 104217193B
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- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06V—IMAGE OR VIDEO RECOGNITION OR UNDERSTANDING
- G06V40/00—Recognition of biometric, human-related or animal-related patterns in image or video data
- G06V40/10—Human or animal bodies, e.g. vehicle occupants or pedestrians; Body parts, e.g. hands
- G06V40/12—Fingerprints or palmprints
- G06V40/13—Sensors therefor
- G06V40/1306—Sensors therefor non-optical, e.g. ultrasonic or capacitive sensing
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- Measurement Of Length, Angles, Or The Like Using Electric Or Magnetic Means (AREA)
Abstract
The present invention is applied to fingerprint recognition field, provide a kind of capacitive fingerprint sensor circuit and inductor, sensor circuit includes cancellation module and feedback amplifier, the first input end of cancellation module is connected with the first external driving source, second input of cancellation module is connected by being pressed against the finger of second input with the second external driving source, the output end of cancellation module and the input of feedback amplifier connect, first external driving source and the signal of the second external driving source output are anti-phase each other, first external driving source is linked into the signal of cancellation module and the second external driving source is coupled to the signal generation counteracting of cancellation module, obtain the fingerprint induced signal related to fingerprint depth, the output end of feedback amplifier exports amplified fingerprint induced signal.The capacitive fingerprint sensor circuit and inductor of the embodiment of the present invention have been decayed the part unrelated with fingerprint by external driving source anti-phase each other and cancellation module, only amplify difference mode signal, improve the sensitivity of fingerprint sensing.
Description
Technical field
The invention belongs to fingerprint recognition field, more particularly to a kind of capacitive fingerprint sensor circuit and inductor.
Background technology
The finger lines of people has depth difference, and convex place is referred to as " peak (ridge) ", and recessed place is referred to as " paddy
(valley)”.Capacitance type fingerprint induction system is of different sizes using inductance capacitance corresponding to " peak " and " paddy " included on fingerprint,
The amplitude of output signal also different principle, the image information at " peak " and " paddy " is converted under same AC signal excitation
Corresponding electric signal.
To prevent from touching electrostatic damage of the process to fingerprint inductor repeatedly, and mechanical strength is improved, need to be in fingerprint sense
Device surface is answered to place nonconducting thick dielectric layer (cover), so as to produce dielectric layer relevant capacitor (common mode part)；Other fingerprint
Depth is that fingerprint " peak " and " paddy " produce the electric capacity related to depth of lines, and both constitute finger to sensor sensing electrode
Coupled capacitor (differential-mode portion).Prior art is as shown in figure 1, by charge amplifier by differential-mode portion and the summation of common mode part
Directly amplify, differential-mode portion ratio very little shared in the summation, such differential-mode portion can be submerged in summation, it is not easy to point
The difference of " peak " and " paddy " is discerned, i.e. the sensitivity of fingerprint inductor is relatively low.
The content of the invention
The purpose of the embodiment of the present invention is to provide a kind of capacitive fingerprint sensor circuit and inductor, it is intended to solves existing
The problem of fingerprint inductor poor sensitivity.
The embodiment of the present invention is achieved in that a kind of capacitive fingerprint sensor circuit, including cancellation module and feedback amplify
Device, the first input end of the cancellation module are connected with the first external driving source, and the second input of the cancellation module passes through
The finger for being pressed against second input is connected with the second external driving source, and the output end of the cancellation module is put with the feedback
The signal of the input connection of big device, the first external driving source and the second external driving source output is anti-phase each other, institute
State that the first external driving source is sent to the signal of the cancellation module and the described second external driving source is coupled to the counteracting mould
The signal of block produces counteracting, obtains the fingerprint induced signal related to fingerprint depth, the output end output of the feedback amplifier
Amplified fingerprint induced signal.
Further, the cancellation module includes inductance capacitance CsWith counteracting electric capacity Cc, the inductance capacitance CsInput
For the second input of the cancellation module, the inductance capacitance CsOutput end and the counteracting electric capacity CcOutput end connection,
The C for offsetting electric capacitycInput be the cancellation module first input end, the inductance capacitance CsElectricity is offset with described
Hold CcTie point be the cancellation module output end.
Further, the second input of the cancellation module includes induction plate, between finger and the induction plate
Isolated by dielectric layer, form the inductance capacitance Cs, the first input end of the cancellation module, which includes, offsets pole plate, the sense
Answer and the counteracting electric capacity C is formed between pole plate and the counteracting pole platec。
Further, the induction plate and the counteracting pole plate are formed by metal level.
Further, the feedback amplifier is current amplifier, and the current amplifier includes the first low noise amplifier
And it is connected to the resistance between the input of first low noise amplifier and output end.
Further, the feedback amplifier is charge amplifier, and the charge amplifier includes the second low noise amplifier
And it is connected to the feedback capacity between the input of second low noise amplifier and output end.
Further, the feedback amplifier also includes being connected to first low noise amplifier or second low noise
Reset switch between the input and output end of amplifier.
Further, the capacitive fingerprint sensor circuit also includes driving amplifier and offsets amplifier, and the driving is put
The input of big device is connected with external driving source, and the output end of the driving amplifier is defeated with being pressed against the cancellation module second
Enter the finger connection at end；The input for offsetting amplifier is connected with the external driving source, described to offset the defeated of amplifier
Go out end to be connected with the first input end of the cancellation module；The gain of the driving amplifier and the counteracting amplifier is anti-phase.
The present invention also proposes a kind of capacitive fingerprint inductor, and the capacitive fingerprint inductor includes multiple pixel cells, often
The corresponding capacitive fingerprint sensor circuit of individual pixel cell, the capacitive fingerprint sensor circuit are any electric capacity as described above
Fingerprint sensor circuit.
Further, the capacitive fingerprint inductor also includes driving amplifier and offsets amplifier, the drive amplification
The input of device is connected with external driving source, and the output end of the driving amplifier is with being pressed against each capacitive fingerprint sensor circuit
Cancellation module the second input finger connection, it is described offset amplifier input be connected with the external driving source,
The output end for offsetting amplifier is connected with the first input end of the cancellation module of each capacitive fingerprint sensor circuit, the drive
The gain of dynamic amplifier and the counteracting amplifier is anti-phase.
The part of the invention unrelated with fingerprint of having been decayed by external driving source anti-phase each other and cancellation module, only amplifies
The difference mode signal related to fingerprint depth, therefore the amplifier of subsequent cascaded is not easy saturation, reduces the reality of fingerprint inductor
Existing difficulty, improves the sensitivity of fingerprint inductor.Further, the gain of amplifier is offset by changing, is suitable for difference
The dielectric layer of thickness and material, improve the compatibility of fingerprint sensor.Due to introducing the electricity of the stable induction plate of feedback amplifier
Pressure, therefore signal processing is unrelated with the parasitic capacitance of induction electrode, improves system reliability, and the electric capacity in the present invention refers to
Line sensor circuit is simple for structure, compatibility standard CMOS technology, and integrated cost is low.
Brief description of the drawings
Fig. 1 is the circuit diagram of the fingerprint inductor of prior art；
Fig. 2 is the circuit diagram for the capacitive fingerprint sensor circuit that the embodiment of the present invention one provides；
Fig. 3 is another circuit diagram for the capacitive fingerprint sensor circuit that the embodiment of the present invention one provides；
Fig. 4 is the structure chart for the capacitive fingerprint sensor circuit that the embodiment of the present invention one provides；
Fig. 5 is the circuit diagram for the capacitive fingerprint inductor that the embodiment of the present invention two provides；
Fig. 6 is the circuit diagram of the capacitive fingerprint inductor for more pixel cells that the embodiment of the present invention two provides.
Embodiment
In order to make the purpose , technical scheme and advantage of the present invention be clearer, it is right below in conjunction with drawings and Examples
The present invention is further elaborated.It should be appreciated that the specific embodiments described herein are merely illustrative of the present invention, and
It is not used in the restriction present invention.
Embodiment one
The embodiment of the present invention one proposes a kind of capacitive fingerprint sensor circuit.As shown in Fig. 2 the electric capacity of the embodiment of the present invention one
Fingerprint sensor circuit includes cancellation module 10 and feedback amplifier 20, the first input end of cancellation module 10 and the first external driving
Source VS1 connections, the second input of cancellation module 10 pass through the external driving source of finger and second that is pressed against second input
VS2 connections, the output end of cancellation module 10 are connected with the input of feedback amplifier 20, the first external driving source VS1 and second
The signal of external driving source VS2 outputs is anti-phase each other, and the first external driving source VS1 is sent to the signal and second of cancellation module 10
The signal that external driving source VS2 is coupled to cancellation module 10 produces counteracting, obtains the fingerprint induced signal related to fingerprint depth,
The output end of feedback amplifier 20 exports amplified fingerprint induced signal.In the embodiment of the present invention one, feedback amplifier
20 can be current amplifier or charge amplifier, for convenience of explanation, be illustrated by taking charge amplifier 20 as an example.
The embodiment of the present invention one is operated by the counteracting of cancellation module 10, declined before finger coupled signal is amplified first
Subtract the signal section unrelated with fingerprint, then amplify the small-signal part related to lines by charge amplifier 20, then it is defeated
Go out to the other parts of fingerprint inductor to be amplified, the operation such as analog-to-digital conversion, image mosaic, extract effective fingerprint letter
Breath, realizes the processing to fingerprint signal.
As shown in figure 3, cancellation module 10 includes inductance capacitance CsWith counteracting electric capacity Cc.Inductance capacitance CsInput be to
Second input of the module that disappears 10, inductance capacitance CsOutput end with offsetting electric capacity CcOutput end connection, offset the C of electric capacityc's
Input be cancellation module 10 first input end, inductance capacitance CsWith counteracting electric capacity CcTie point it is defeated for cancellation module 10
Go out end.
Charge amplifier 20 includes the second low noise amplifier (Low Noise Amplifier, LNA) 107 and is connected to
Feedback capacity C between the input and output end of second low noise amplifier 107fb.Charge amplifier 20, which may also include, to be connected to
Reset switch SW between the input and output end of second low noise amplifier 107, for that will input and export in reseting stage
Node voltage is set to bias voltage.
In the embodiment of the present invention one, capacitive fingerprint sensor circuit may also include driving amplifier 101 and offset amplifier
102, the input of driving amplifier 101 is connected with external driving source VS, and output end is with being pressed against the input of cancellation module 10 second
The finger connection at end, the input for offsetting amplifier 102 are connected with external driving source VS, output end and the first of cancellation module 10
Input connects, and the gain of driving amplifier 101 and counteracting amplifier 102 is anti-phase.
The structure chart of capacitive fingerprint sensor circuit is as shown in figure 4, wherein comprising induction plate 201, offset pole plate 202 and anti-
Pole plate 203 is presented, is isolated between finger and induction plate 201 by the dielectric layer 204 of insulation, when finger contacts or be pressed against fingerprint
When on a certain pixel cell of inductor, inductance capacitance C is formed between finger and induction plates, induction plate 201 is with offsetting pole
Formed between plate 202 and offset electric capacity Cc, feed back and feedback capacity C formed between pole plate 203 and induction plate 202fb.In order to improve electricity
The integrated level on road, induction plate 201, pole plate 202 and feedback pole plate 203 is offset using metal level composition.
It can be seen from the calculation formula of capacity plate antenna, inductance capacitance CsCapacitance and insulating materials dielectric constant into just
Than the distance between upper bottom crown is inversely proportional, therefore inductance capacitance C corresponding to the peak and valley of fingersIt is of different sizes, induced electricity
Hold CsTwo parts can be divided into：Common mode part (factor such as material, thickness to the dielectric layer 204 of insulation is related)；Differential-mode portion (with
The depth of fingerprint lines is related).The signal for being coupled to induction plate 201 also divides into common mode part and differential mode portion accordingly
Point, and the capacitance difference of finger lines peak and valley is effective detected object of fingerprint sensor circuit.
In the embodiment of the present invention one, driving amplifier 101, finger, inductance capacitance CsCoupled signal vias is formed, counteracting is put
Big device 102, offset electric capacity CcOffseting signal path is formed, both are connected to induction plate 201, are re-fed into the second low noise amplifier
107 carry out signal amplification.In finger the electricity related to finger lines is distinguished into the weaker coupled capacitor of fingerprint sensor circuit
Hold, and retain the half-tone information of peak valley.
Specifically, when finger touches the surface of fingerprint sensor circuit, external driving source VS is through overdriven amplifier 101
It is loaded into after A1 times of amplification on finger, and passes through inductance capacitance CsIt is coupled to induction plate 201.Meanwhile external driving source VS warps
Offset after amplifier 102 amplifies A2 times by offsetting electric capacity CcIt is coupled to induction plate 201.After two Signal averagings, coupling
The common mode part of signal is partially or completely counteracting, and differential-mode portion is sent into the negative input end of the second low noise amplifier 107.
Feedback capacity CfbIt is connected between negative input end and the output of the second low noise amplifier 107, due to the second LNA
The negative feedback of big device 107, the voltage of induction plate 201 keep constant, inductance capacitance CsWith counteracting electric capacity CcElectric charge summation
Afterwards, it is transferred to feedback capacity CfbOn, obtain output voltage VO UT.
Reset switch SW is connected between the input and output of the second low noise amplifier 107, reseting stage will input and
Output node voltage is set to bias voltage VCM.
To further illustrate the negative function of the cancellation module 10 of the embodiment of the present invention one, the meter of relevant parameter is listed below
Calculate.
The coupled capacitor of fingerprint to induction plate 201 is relevant with the pressing situation of dielectric layer and finger.If finger with
The surface contact of fingerprint sensor circuit is close, then coupled capacitor depends primarily on the dielectric constant, thickness and sensing of dielectric layer
The area of pole plate 201.If peak valley and the contact defective tightness of fingerprint sensor circuit, have the air related to pressing situation to be situated between
Matter capacitive part.Assuming that inductance capacitance corresponding to the peak of finger is Csr, inductance capacitance corresponding to paddy is Csv, and both differences are
Δ Cs, i.e. Csv=Csr+ Δs Cs.
The electric charge that external driving source VS is coupled to induction plate 201 by coupled signal vias is：Vs*A1*Cs.
Electric charge by offseting signal vias couple to induction electrode 201 is：Vs*A2*Cc.
Due to the presence of negative-feedback, the voltage of induction plate 201 keeps constant, and parasitic capacitance Cg electric charge is constant, is not involved in
Signal amplification process.
Electric charge is in inductance capacitance Cs, offset electric capacity CcWith feedback capacity CfbBetween shift after the completion of, output voltage is：
Vout=(VS*A1*Cs+VS*A2*Cc)/Cfb；
Output voltage is corresponding to peak：Voutr=(VS*A1*Csr+VS*A2*Cc)/Cfb；
Output voltage is corresponding to paddy：
Voutv=(VS*A1*Csv+VS*A2*Cc)/Cfb=(VS*A1*Csr+VS*A2*Cc)/Cfb+VS*A1* Δs Cs/
Cfb；
Voutc=(VS*A1*Csr+VS*A2*Cc)/Cfb is recorded, is common mode part；Voutd=VS*A1* Δ Cs/Cfb,
For differential-mode portion.The gray scale being only concerned due to finger print information between peak valley, therefore by adjusting A2 so that A2*Cc=-A1*Csr
(it can thus be appreciated that A1 and A2 symbol is on the contrary, the gain of i.e. driving amplifier 101 and counteracting amplifier 102 is anti-phase, into counteracting mould
The signal of the first input end of block 10 and the second input is anti-phase each other), it can decay or even eliminate Voutc, while not reduce
Voutd。
Assuming that the relative dielectric constant of the insulating materials used is 10, thickness 300um, finger and fingerprint sensor circuit
Contact may be assumed that, for capacity plate antenna, area corresponding to single pixel point is 50um*50um, according to the calculation formula of capacity plate antenna,
Inductance capacitance size is：Cs≈0.74fF.
Assuming that Csr=1fF, Csv=0.95fF, Δ Cs=-0.05fF, Cfb=10fF, Cc=10fF；VS=1V, A1=
10.If operated without offsetting, the amplitude of the output signal of the second low noise amplifier 107 is：Voutr=Voutc=1V,
Voutv=Voutc+Voutd=950mV.If the follow up amplifier of capacitive fingerprint sensor circuit is (with the second low noise amplifier
107 VOUT ends are connected) working power be 2V, common-mode point VCM=1V, then amplitude output signal is reachable after gain is set to 1 times
To 0~2V, there is saturation in amplifier, and useful signal is that the amplitude of difference mode signal can not amplify.
If the gain A 2=-1 of amplifier 102 is offset in setting, by the partially complete counteracting of common mode, then the second low noise is amplified
The amplitude of the output signal of device 107 is：Voutr=Voutc=0, Voutv=Voutc+Voutd=-50mV.Capacitive fingerprint senses
The follow up amplifier gain of circuit can be set to sufficiently large (such as 15 times), and occur without saturation.Useful signal is the width of difference mode signal
Degree is exaggerated 15 times, so as to improve the sensitivity of lines identification.
It was found from above-mentioned analysis process, a counteracting operation to work well, change A1/A2, meet condition：A1*Csr
=-A2*Cc.Because Csr is relevant with the material and thickness of medium, therefore by changing A2 size, it is suitable for different media
Layer.
As shown in figure 5, also available current amplifier replaces the charge amplifier 20 in above-described embodiment, to complete identical
Function.Current amplifier includes the first low noise amplifier 107 and is connected to input and the output of the first low noise amplifier 107
Resistance Rfb between end, it may also include the reset switch between the input for being connected to the first low noise amplifier 107 and output end
SW。
In summary, the capacitive fingerprint sensor circuit of the embodiment of the present invention one, operated by offsetting, improve fingerprint sensing
It is convenient subsequently to be amplified while circuit sensitivity, improve subsequent treatment precision.Further, amplification is offset by changing
The gain of device, the dielectric layer of different-thickness and material is suitable for, improves the compatibility of fingerprint sensor.Due to introducing feedback amplification
The voltage of the stable induction plate of device, therefore signal processing is unrelated with the parasitic capacitance of induction electrode, and it is reliable to improve system
Property.Circuit structure of the embodiment of the present invention is succinct, compatibility standard CMOS technology, and integrated cost is low.
Embodiment two
In order to reach enough resolution ratio DPI (dots per inch), the available area of capacitive fingerprint sensor circuit compared with
It is small, the corresponding capacitive fingerprint sensor circuit of a pixel cell, and driving amplifier and counteracting amplifier then can be by multiple pictures
Plain units shared.Therefore, the embodiment of the present invention two proposes a kind of capacitive fingerprint inductor, as shown in fig. 6, the embodiment of the present invention two
Capacitive fingerprint inductor include multiple pixel cells, the corresponding capacitive fingerprint sensor circuit of each pixel cell.Also include
Driving amplifier 401 and counteracting amplifier 402, the input of driving amplifier 401 are connected with external driving source VS, and output end is led to
The finger connection of the second input of the cancellation module 40 for being pressed against each capacitive fingerprint sensor circuit is crossed, offsets amplifier 402
Input be connected with external driving source VS, the first input of the cancellation module 40 of output end and each capacitive fingerprint sensor circuit
End connection, the gain of driving amplifier 401 and counteracting amplifier 402 are anti-phase.
The structure and operation principle of the capacitive fingerprint sensor circuit and the capacitive fingerprint sensor circuit shown in Fig. 2 to Fig. 3
Similar, here is omitted.
Capacitive fingerprint sensor circuit is the elementary cell of capacitance-typed fingerprint sensor, and finger is by dielectric layer by drive signal
It is coupled to induction electrode 301, while drive signal is also by built-in counteracting electric capacity CcInduction electrode 301 is sent into, so as to decay
Or the public coupled signal unrelated with fingerprint is eliminated, then amplify residual signal and be output to subsequent process circuit.
The foregoing is merely illustrative of the preferred embodiments of the present invention, is not intended to limit the invention, all essences in the present invention
All any modification, equivalent and improvement made within refreshing and principle etc., should be included in the scope of the protection.
Claims (8)
- A kind of 1. capacitive fingerprint sensor circuit, it is characterised in that including cancellation module and feedback amplifier, the cancellation module First input end is connected with the first external driving source, and the second input of the cancellation module is by being pressed against second input Finger be connected with the second external driving source, the output end of the cancellation module is connected with the input of the feedback amplifier, The first external driving source and the signal of the second external driving source output are anti-phase each other, and the first external driving source is sent The signal for entering to the signal of the cancellation module and the described second external driving source to be coupled to the cancellation module produces counteracting, obtains To the fingerprint induced signal related to fingerprint depth, the output end of the feedback amplifier exports amplified fingerprint sensing letter Number；The cancellation module includes inductance capacitance (Cs) and counteracting electric capacity (Cc), the inductance capacitance (Cs) input supported to be described Second input of the module that disappears, the inductance capacitance (Cs) output end and the counteracting electric capacity (Cc) output end connection, it is described Offset electric capacity (Cc) input be the cancellation module first input end, the inductance capacitance (Cs) and the counteracting electric capacity (Cc) tie point be the cancellation module output end；Second input of the cancellation module includes induction plate, finger Isolated between the induction plate by dielectric layer, form the inductance capacitance (Cs), the first input of the cancellation module End forms the counteracting electric capacity (C comprising pole plate is offset between the induction plate and the counteracting pole platec)。
- 2. capacitive fingerprint sensor circuit as claimed in claim 1, it is characterised in that the induction plate and the counteracting pole plate Formed using metal level.
- 3. capacitive fingerprint sensor circuit as claimed in claim 1, it is characterised in that the feedback amplifier is Current amplifier Device, the current amplifier include the first low noise amplifier and are connected to input and the output of first low noise amplifier Resistance between end.
- 4. capacitive fingerprint sensor circuit as claimed in claim 1, it is characterised in that the feedback amplifier amplifies for electric charge Device, the charge amplifier include the second low noise amplifier and are connected to input and the output of second low noise amplifier Feedback capacity between end.
- 5. capacitive fingerprint sensor circuit as claimed in claim 1, it is characterised in that the feedback amplifier also includes being connected to Reset switch between the input and output end of first low noise amplifier or second low noise amplifier.
- 6. the capacitive fingerprint sensor circuit as any one of claim 1 to 5, it is characterised in that also including drive amplification Device and counteracting amplifier, the input of the driving amplifier are connected with external driving source, the output end of the driving amplifier It is connected with the finger for being pressed against the input of cancellation module second；The input for offsetting amplifier and the external driving Source is connected, and the output end for offsetting amplifier is connected with the first input end of the cancellation module；The driving amplifier and The gain of the counteracting amplifier is anti-phase.
- 7. a kind of capacitive fingerprint inductor, it is characterised in that the capacitive fingerprint inductor includes multiple pixel cells, each picture The corresponding capacitive fingerprint sensor circuit of plain unit, the capacitive fingerprint sensor circuit are any one of claim 1 to 5 Capacitive fingerprint sensor circuit.
- 8. capacitive fingerprint inductor as claimed in claim 7, it is characterised in that also including driving amplifier and offset amplification Device, the input of the driving amplifier are connected with external driving source, and the output end of the driving amplifier is each with being pressed against Second input of the cancellation module of capacitive fingerprint sensor circuit finger connection, it is described offset amplifier input with it is described The first of the connection of external driving source, the output end for offsetting amplifier and the cancellation module of each capacitive fingerprint sensor circuit is defeated Enter end connection, the gain of the driving amplifier and the counteracting amplifier is anti-phase.
Priority Applications (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201711156322.5A CN107704852A (en) | 2014-03-20 | 2014-03-20 | Capacitive fingerprint sensor circuit and inductor |
| CN201410105847.6A CN104217193B (en) | 2014-03-20 | 2014-03-20 | Capacitive fingerprint sensor circuit and inductor |
| PCT/CN2014/088451 WO2015139447A1 (en) | 2014-03-20 | 2014-10-13 | Capacitive fingerprint sensing circuit and sensor |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201410105847.6A CN104217193B (en) | 2014-03-20 | 2014-03-20 | Capacitive fingerprint sensor circuit and inductor |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201711156322.5A Division CN107704852A (en) | 2014-03-20 | 2014-03-20 | Capacitive fingerprint sensor circuit and inductor |
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| Publication Number | Publication Date |
|---|---|
| CN104217193A CN104217193A (en) | 2014-12-17 |
| CN104217193B true CN104217193B (en) | 2017-12-19 |
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| CN201410105847.6A Expired - Fee Related CN104217193B (en) | 2014-03-20 | 2014-03-20 | Capacitive fingerprint sensor circuit and inductor |
| CN201711156322.5A Pending CN107704852A (en) | 2014-03-20 | 2014-03-20 | Capacitive fingerprint sensor circuit and inductor |
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| Application Number | Title | Priority Date | Filing Date |
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| CN110265457B (en) * | 2019-06-27 | 2021-11-02 | 京东方科技集团股份有限公司 | Organic light emitting display panel and preparation method thereof |
| CN110781868B (en) * | 2019-11-21 | 2024-12-06 | 上海思立微电子科技有限公司 | Pixel circuit, pixel array, optical fingerprint sensor and fingerprint acquisition method |
| CN111769828A (en) * | 2020-07-14 | 2020-10-13 | 成都芯思源科技有限公司 | Capacitive touch key circuit and electronic equipment |
| CN113467648A (en) * | 2021-07-01 | 2021-10-01 | 维沃移动通信有限公司 | Electronic device |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2003028607A (en) * | 2001-07-12 | 2003-01-29 | Sony Corp | Capacitance detector and fingerprint collation apparatus using the same |
| US6636053B1 (en) * | 2001-11-02 | 2003-10-21 | Stmicroelectronics, Inc. | Capacitive pixel for fingerprint sensor |
| JP4036798B2 (en) * | 2003-07-29 | 2008-01-23 | アルプス電気株式会社 | Capacitance detection circuit, detection method, and fingerprint sensor |
| JP4432625B2 (en) * | 2003-09-05 | 2010-03-17 | セイコーエプソン株式会社 | Capacitance detection device |
| CN1278270C (en) * | 2004-04-22 | 2006-10-04 | 芯微技术（深圳）有限公司 | Semiconductor acquisition element for fingerprint |
| WO2005124659A1 (en) * | 2004-06-18 | 2005-12-29 | Fingerprint Cards Ab | Fingerprint sensor element |
| US8115497B2 (en) * | 2007-11-13 | 2012-02-14 | Authentec, Inc. | Pixel sensing circuit with common mode cancellation |
| CN101858941A (en) * | 2010-03-30 | 2010-10-13 | 矽创电子股份有限公司 | Capacitance sensing circuit with anti-electromagnetic interference capability |
| JP5231605B2 (en) * | 2011-06-10 | 2013-07-10 | シャープ株式会社 | Touch panel controller and electronic device using the same |
-
2014
- 2014-03-20 CN CN201410105847.6A patent/CN104217193B/en not_active Expired - Fee Related
- 2014-03-20 CN CN201711156322.5A patent/CN107704852A/en active Pending
- 2014-10-13 WO PCT/CN2014/088451 patent/WO2015139447A1/en active Application Filing
Also Published As
| Publication number | Publication date |
|---|---|
| CN104217193A (en) | 2014-12-17 |
| WO2015139447A1 (en) | 2015-09-24 |
| CN107704852A (en) | 2018-02-16 |
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