CN101520837B - Capacitance-typed fingerprint sensor and panel thereof - Google Patents

Abstract

The invention discloses a capacitance-type fingerprint sensor, which comprises a fingerprint capacitor CF, a reference capacitor, a first transistor and a second transistor. Capacitance value of the fThe invention discloses a capacitance-type fingerprint sensor, which comprises a fingerprint capacitor CF, a reference capacitor, a first transistor and a second transistor. Capacitance value of the fingerprint capacitor CF is a concave-part capacitance value CFV or a convex-part capacitance value CFR. The reference capacitor has a capacitance value CS, and CFV is less than CS which is less than Cingerprint capacitor CF is a concave-part capacitance value CFV or a convex-part capacitance value CFR. The reference capacitor has a capacitance value CS, and CFV is less than CS which is less than CFR. The first transistor is used for pre-charging the reference capacitor and the fingerprint capacitor in a pre-charging stage. The second transistor is used for outputting voltage of the fingerprintFR. The first transistor is used for pre-charging the reference capacitor and the fingerprint capacitor in a pre-charging stage. The second transistor is used for outputting voltage of the fingerprintcapacitor to a reading wire in an estimating stage. The pre-charging stage is controlled by a first reading selection wire, the estimating stage is controlled by a second reading selection wire which capacitor to a reading wire in an estimating stage. The pre-charging stage is controlled by a first reading selection wire, the estimating stage is controlled by a second reading selection wire which is adjacent to the first reading selection wire, and the effective time of accessing the first reading selection wire is within a starting period of the second reading selection wire.is adjacent to the first reading selection wire, and the effective time of accessing the first reading selection wire is within a starting period of the second reading selection wire.

Description

Capacitance-typed fingerprint sensor and panel thereof

Technical field

The present invention relates to a kind of capacitance-typed fingerprint sensor and panel thereof, particularly relate to a plurality of transistorized capacitance-typed fingerprint sensors of a kind of use and panel thereof.

Background technology

Fingerprint inductor is a kind of inductor that is used to recognize finger grain pattern formula and the person identification of fiduciary level is provided.This fingerprint inductor also is used in portable product widely, and for example mobile phone, notebook computer are in order to guarantee the security of individual private data.

Figure 1A and 1B show the equivalent electrical circuit of fingerprint inductor.By and large, fingerprint inductor can be implemented in the chip, represents a protective seam in the numbering 13 of Figure 1A, and it is as capacitor C _dDielectric layer.If this fingerprint inductor is embedded in an image panel, represents an ITO layer in the numbering 11 of Figure 1A, and number 13 and represent glass and film, for example colored filter, Polarizer etc.Following narration is an example with the fingerprint inductor that is embedded in image panel.At Figure 1A, a metal level 11 and a substrate 12 are with the series system combination on the glass 13, one, and this glass 13 persons of being to use point the place that can touch.A common capacitor C _dBe present in the glass 13, and a capacitor C _PBe present between metal level 11 and the substrate 12.At Figure 1B, the surface of user's finger can be divided into protuberance 14 and recess 15.This recess 15 and this glass 13 have one apart from d ₂, and the thickness of this glass 13 is d ₁Based on this structure, an extra capacitor C2 is present in the recess of this user's finger and the surface of this glass 13.This protuberance capacitance C _FRRelevant with CI, this recess capacitance C _FVRelevant with CI/C2, the equivalent capacity of CI and C2 can be represented with following mode:

$C_{\mathrm{FR}}={\mathrm{<figure-callout\; id="1"\; label="C"\; filenames="S200810081311XE00021.png,S200810081311XE00031.png"\; state="\{\{state\}\}">C</figure-callout>}}_1=\frac{{\mathrm{\&epsiv;}}_{1}A}{{\mathrm{<figure-callout\; id="1"\; label="d"\; filenames="S200810081311XE00021.png,S200810081311XE00031.png"\; state="\{\{state\}\}">d</figure-callout>}}_1},$ And $C_{\mathrm{FV}}={\mathrm{<figure-callout\; id="1"\; label="C"\; filenames="S200810081311XE00021.png,S200810081311XE00031.png"\; state="\{\{state\}\}">C</figure-callout>}}_1//C_2=\frac{1}{\frac{{\mathrm{<figure-callout\; id="1"\; label="d"\; filenames="S200810081311XE00021.png,S200810081311XE00031.png"\; state="\{\{state\}\}">d</figure-callout>}}_1}{{\mathrm{\&epsiv;}}_{1}A}+\frac{d_2}{{\mathrm{\&epsiv;}}_{2}A}}$

Common this protuberance capacitance C _FRMuch larger than this recess capacitance C _FV

In order to respond to user's finger, a sensing circuit should distinguishable this protuberance capacitance and recess capacitance.Yet it also is not easy to obtain required accuracy, because the factor on some environment, and noise or cross-talk this result that all can detract for example.

Summary of the invention

One embodiment of capacitance-typed fingerprint sensor of the present invention comprises a first transistor, a fingerprint capacitor, a reference capacitance and a transistor seconds.This first transistor comprises a gate terminal, an input end and an output terminal, and wherein, this gate terminal is read selection wire by one first and controlled, and this input end is connected to a bias voltage VA.This fingerprint capacitor is connected to the output terminal of this first transistor, and wherein, the capacitance of this fingerprint capacitor is a recess capacitance C _FVAn or protuberance capacitance C _FROne end of this reference capacitance is connected to the output terminal of this first transistor, and the other end is connected to one second and reads selection wire, and wherein, this second is read selection wire and be in close proximity to this and first read selection wire, and this reference capacitance has a capacitance C _S, and C _FV＜C _S＜C _FRThis transistor seconds comprises a gate terminal, an input end and an output terminal, and wherein, this gate terminal is controlled by the one scan line, and this input end is connected to this reference capacitance, and this output terminal is connected to a sense wire.

Another embodiment of capacitance-typed fingerprint sensor of the present invention comprises a fingerprint capacitor C _F, a reference capacitance, a first transistor and a transistor seconds.This fingerprint capacitor C _FCapacitance be a recess capacitance C _FVAn or protuberance capacitance C _FRThis reference capacitance has a capacitance C _S, and C _FV＜C _S＜C _FRThis first electric crystal is used for this reference capacitance of precharge and fingerprint capacitor when a pre-charging stage.This transistor seconds is used for exporting voltage to one sense wire of this fingerprint capacitor when an estimating stage.This pre-charging stage is read selection wire by one first and is controlled, this estimating stage is read selection wire by one second and is controlled, this second is read selection wire and is in close proximity to this and first reads selection wire, and is positioned at this effective time of this sense wire of access and second reads between the starting period of selection wire.

An embodiment who comprises the panel system of capacitance-typed fingerprint sensor of the present invention comprises active-matrix zone, a data driver, one scan driver, a sensing circuit and the image processing circuit with capacitance-typed fingerprint sensor.This data driver is used to drive the data line of image pixel.This scanner driver is used for the sweep trace of control linkage to this capacitance-typed fingerprint sensor.The kind that this sensing circuit is used to receive the sense wire of this capacitance-typed fingerprint sensor and recognizes this fingerprint capacitor.This image processing circuit is connected to this sensing circuit.

Description of drawings

Figure 1A and 1B show the equivalent electrical circuit of fingerprint inductor;

Fig. 2 shows a specific embodiment of panel of the present invention;

Fig. 3 shows a specific embodiment of fingerprint inductor of the present invention;

The sequential chart of Fig. 4 displayed map 3 circuit;

The pre-charging stage and the estimating stage of Fig. 5 A and 5B displayed map 3 circuit; And

Fig. 6 shows the sensing circuit of a specific embodiment of the present invention.

The reference numeral explanation

Sheet metal on 11 12Substrate

13 protective seams 14The fingerprint protuberance

15 fingerprint recesses

21 data drivers 22Scanner driver

23 sensing circuits 24Image processing circuit

25 panels

31 capacitance-typed fingerprint sensors 32Capacitance-typed fingerprint sensor

33 the first transistors 34Transistor seconds

C _FFingerprint capacitor C _SReference capacitance

61 comparers 62Multiplexer.

Embodiment

Fig. 2 shows a specific embodiment of panel of the present invention.This panel system comprises an active-matrix zone 25, a data driver 21, one scan driver 22, a sensing circuit 23 and an image processing circuit 24.This active-matrix zone 25 comprises a plurality of capacitance-typed fingerprint sensors 31, and each capacitance-typed fingerprint sensor 31 can optionally coexist as a pixel cell with an image pixel.This data driver 21 is used for driving data.This scanner driver 22 is used for the sweep trace of control linkage to this capacitance-typed fingerprint sensor 31.By and large, when this capacitance-typed fingerprint sensor 31 was operated, the sweep trace that is connected to this capacitance-typed fingerprint sensor 31 was activated in the whole operation process.This sensing circuit 23 is used to receive the simulating signal of the sense wire of this capacitance-typed fingerprint sensor 31, and recognizes the pattern of this fingerprint capacitor 31, for example recess capacitance C _FVOr protuberance capacitance C _FRThis image processing circuit 24 is connected to this sensing circuit 23.The structure of Fig. 2 is that the damascene structures with image panel is an example, can be changed easily and be applied in the chip but be familiar with the structure that this operator all can know Fig. 2.

Fig. 3 shows a specific embodiment of fingerprint inductor of the present invention.This capacitance-typed fingerprint sensor 31 comprises a first transistor 33, a transistor seconds 34, a fingerprint capacitor C _FAn and reference capacitance C _SFig. 3 has shown two groups of adjacent fingerprint inductors 31 of the same delegation that is connected to same sweep trace.By and large, when a capacitance-typed fingerprint sensor 31 in a pre-charging stage, 32 of adjacent capacitance-typed fingerprint sensors of its prime are in an estimating stage.When this capacitance-typed fingerprint sensor 31 in an estimating stage, the adjacent capacitance-typed fingerprint sensor of level is then in a pre-charging stage thereafter.This first transistor 33 comprises a gate terminal, an input end and an output terminal, and wherein, this gate terminal is read selection wire C by one first _mControl, and this input end is connected to a bias voltage VA.This transistor seconds 34 comprises a gate terminal, an input end and an output terminal, and wherein, this gate terminal is by one scan line R _nControl, this input end is connected to this reference capacitance, and this output terminal is connected to a sense wire.This fingerprint capacitor C _FBe connected to the input end of this transistor seconds 34, wherein, the capacitance of this fingerprint capacitor is a recess capacitance C _FVAn or protuberance capacitance C _FRThis reference capacitance is connected to the output terminal of this first transistor 33, and wherein, this reference capacitance has a capacitance C _S, and C _FV＜C _S＜C _FR

The sequential chart of Fig. 4 displayed map 3 circuit.By and large, share same sweep trace R in the fingerprint capacitor of same row _n, it is activated in the whole operation process that this is listed as all fingerprint capacitor.This that is connected to each fingerprint inductor read selection wire C ₀To C _xStarted in proper order and overlapping each other.This reads selection wire C ₀To C _xBe used in the pre-charging stage and the estimating stage that start each fingerprint inductor, with sequentially by same row fingerprint inductor reading of data corresponding to this sweep trace.Each pulse width of reading selection wire is represented as VD.This sensing circuit 23 reads this sense wire at the selection wire of reading of correspondence before by write off.For example, the time of reading this sense wire [Cm+1] starts from reading selection wire [Cm+1] and is activated, and ends to read selection wire [Cm+1] by write off.

Fig. 5 A is presented at pre-charging stage, the equivalent electrical circuit of this fingerprint inductor 31.In pre-charging stage, this reads selection wire C _mBe activated, this first transistor 33 is enabled, and this bias voltage VA difference this reference capacitance of precharge and this fingerprint capacitor.

Fig. 5 B is presented at estimating stage, the equivalent electrical circuit of this fingerprint inductor 31.In estimating stage, this reads selection wire C _M+1Be activated as VD, and the electric charge that is stored in this reference capacitance and fingerprint capacitor is redistributed.At this moment, sweep trace still is activated, and this transistor seconds 34 is enabled, the position that this sense wire is detected according to user finger, i.e. fingerprint protuberance or recess, and output voltage

Or

Clearly, if the fingerprint recess is detected, then the voltage of its sense wire is greater than the voltage that is detected as if the fingerprint protuberance.

Fig. 6 shows the sensing circuit of a specific embodiment of the present invention.This sensing circuit 23 comprises a multiplexer 62 and a comparer 61.The input end of this multiplexer 62 is connected to this sense wire, and the output terminal of this multiplexer 62 is connected to this comparer 61, and this position of comparer 61 outputs is to this image processing circuit 24.In order to differentiate protuberance electric capacity and recess electric capacity, this comparer 61 uses a threshold voltage V _REF, and $\mathrm{VA}+\frac{C_S}{C_S+C_{\mathrm{FV}}}\&times;\mathrm{VD}>V_{\mathrm{REF}}>\mathrm{VA}+\frac{C_S}{C_S+C_{\mathrm{FR}}}\&times;\mathrm{VD}.$ In view of the above, if these comparer 61 output logic high level, the data that representative is received by fingerprint inductor are recess electric capacity.Otherwise, then be protuberance electric capacity.

Technology contents of the present invention and technical characterstic disclose as above, yet the personage who is familiar with this technology still may be based on teaching of the present invention and announcement and done all replacement and modifications that does not deviate from spirit of the present invention.Therefore, protection scope of the present invention should be not limited to those disclosed embodiments, and should comprise various do not deviate from replacement of the present invention and modifications, and is contained by claim of the present invention.

Claims (11)

1. capacitance-typed fingerprint sensor comprises:

One the first transistor comprises a gate terminal, an input end and an output terminal, and wherein, this gate terminal is read selection wire by one first and controlled, and this input end is connected to a bias voltage VA;

One fingerprint capacitor, an end is connected to the output terminal of this first transistor, other end ground connection, wherein, the capacitance of this fingerprint capacitor is a recess capacitance C _FVAn or protuberance capacitance C _FR

One reference capacitance, the one end is connected to the output terminal of this first transistor, and the other end is connected to one second and reads selection wire, and wherein, this second is read selection wire and is in close proximity to this and first reads selection wire, and this reference capacitance has a capacitance C _S, and C _FV＜C _S＜C _FRAnd

One transistor seconds, comprise a gate terminal, an input end and an output terminal, wherein this gate terminal is controlled by the one scan line, and this input end is connected to an end that is connected with output terminal the first transistor this reference capacitance, and this output terminal is connected to a sense wire.

2. capacitance-typed fingerprint sensor as claimed in claim 1, wherein, in a pre-charging stage, this first is read selection wire and is activated.

3. capacitance-typed fingerprint sensor as claimed in claim 2, wherein, in an estimating stage, this sweep trace and second is read selection wire and is activated, and the exit point voltage of this transistor seconds is output to this sense wire in view of the above.

4. capacitance-typed fingerprint sensor as claimed in claim 3, wherein, tool recess capacitance C _FVThe corresponding read-out voltage of fingerprint capacitor greater than tool protuberance capacitance C _FRThe corresponding read-out voltage of fingerprint capacitor.

5. capacitance-typed fingerprint sensor as claimed in claim 4, wherein, when this estimating stage, the voltage of this sense wire is

Or

And VD represents this second trigger voltage of reading selection wire.

6. capacitance-typed fingerprint sensor as claimed in claim 3, wherein, this sweep trace is activated in this pre-charging stage and estimating stage.

7. panel system that comprises capacitance-typed fingerprint sensor comprises:

One has the active-matrix zone of capacitance-typed fingerprint sensor, and this capacitance-typed fingerprint sensor comprises:

One the first transistor comprises a gate terminal, an input end and an output terminal, and wherein this gate terminal is read selection wire by one first and controlled, and this input end is connected to one first bias voltage VA;

One fingerprint capacitor, an end is connected to the output terminal of this first transistor, other end ground connection, wherein, the capacitance of this fingerprint capacitor is a recess capacitance C _FVAn or protuberance capacitance C _FR

One reference capacitance, the one end is connected to the output terminal of this first transistor, and the other end is connected to one second and reads selection wire, and wherein, this second is read selection wire and is in close proximity to this and first reads selection wire, and this reference capacitance has a capacitance C _S, and C _FV＜C _S＜C _FRAnd

One transistor seconds, comprise a gate terminal, an input end and an output terminal, wherein, this gate terminal is controlled by the one scan line, this input end is connected to an end that is connected with output terminal the first transistor this reference capacitance, and this output terminal is connected to a sense wire;

One data driver is used to drive the data line of image pixel;

The one scan driver is used for the sweep trace of control linkage to this capacitance-typed fingerprint sensor;

One sensing circuit, the kind that is used to receive the sense wire of this capacitance-typed fingerprint sensor and recognizes this fingerprint capacitor, this sensing circuit comprises a multiplexer and a comparer, the input end of this multiplexer is connected to this sense wire, and the output terminal of this multiplexer is connected to an input end of this comparer; And

One image processing circuit is connected to the output terminal of this comparer.

8. panel system as claimed in claim 7, wherein, this comparer has a threshold voltage V _REF, and

And VD represents this second trigger voltage of reading selection wire.

9. panel system as claimed in claim 7, wherein, this active-matrix zone more comprises the image pixel that is connected to this data line.

10. panel system as claimed in claim 7, wherein, when a capacitance-typed fingerprint sensor in a pre-charging stage, the adjacent capacitance-typed fingerprint sensor of its prime is then in an estimating stage.

11. panel system as claimed in claim 7, wherein, when this capacitance-typed fingerprint sensor was operated, the one scan line that is connected to this capacitance-typed fingerprint sensor was activated.

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