CN203799390U - Radiofrequency micro-capacitance fingerprint collecting chip - Google Patents
Radiofrequency micro-capacitance fingerprint collecting chip Download PDFInfo
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- CN203799390U CN203799390U CN201420141710.1U CN201420141710U CN203799390U CN 203799390 U CN203799390 U CN 203799390U CN 201420141710 U CN201420141710 U CN 201420141710U CN 203799390 U CN203799390 U CN 203799390U
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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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Abstract
A radiofrequency micro-capacitance fingerprint collecting chip comprises a plurality of reference sensing unit, a two-dimensional sensing unit array composed of a plurality of sensing units, an insulating layer, an insulating substrate used as a finger contact surface, a radiofrequency signal generating circuit, a radiofrequency drive electrode, a sensing unit array controller, an analog to digital conversion array, a digital to analog converter, a sensing unit offset correction circuit, a fingerprint image buffer, a fingerprint image output controller and an image signal processor, wherein the radiofrequency drive electrode is used for providing power bias switching signals for powering the sensing units on or off, the sensing unit array controller provides time sequence signals required by charging and discharging of the sensing units, and the digital to analog converter is used for controlling the gain of the analog to digital conversion array. The structures of the sensing units are improved, and the sensing unit offset correction circuit is additionally arranged, so that the radiofrequency micro-capacitance fingerprint collecting chip can solve the problems including residual fingerprint, interference of other radiofrequency radiation, fake fingers and detection depth, and the chip can be embedded into a capacitive touch screen.
Description
Technical field
The utility model relates to integrated circuit (IC) design field, relates in particular to a kind of radio frequency decline electric capacity fingerprint collecting chip and acquisition method thereof.
Background technology
Along with people are more and more higher to the requirement of information security, the authentication of living body biological feature and identification apply in daily life more and more.Finger print identifying, as have very high reliability and cost performance in biological characteristic authentication, has become the main flow of current biological identification.Meanwhile, fingerprint collecting technology is high speed development also, the fingerprint sensor of more low-cost, faster speed, small size, low-power consumption, high dynamic range and a high investigation depth will capture huge market, therefore, the fingerprint sensor with above-mentioned advantage becomes the emphasis of current research, wherein, capacitive fingerprint sensing device becomes one of current main product.
Along with the maturation gradually of fingerprint sensing technology, the advanced fingerprint sensing technology that Apple releases has been applied in cell phone and other electronic product, and even Chinese third generation I.D. need also adopt fingerprint sensing technology to carry out the registration of finger print information.Be not difficult to predict, fingerprint identification technology can be very soon and is applied to widely our daily life, is particularly applied in mobile device.
Meanwhile, high demand must can become more and more higher to the requirement of the performance of fingerprint sensor.A good fingerprint recognition system, not only can solve the deficiency existing in fingerprint sensor from algorithm, more should fundamentally solve the acquisition quality problem of sensor.That is to say, be applied to the fingerprint sensor on mobile device, it must have very high investigation depth to meet application requirements, preferably can fingerprint sensor is placed under contact panel or be integrated in contact panel and do not affect the outward appearance of its performance and mobile device.
Existing domestic fingerprint sensor is all pure capacitive fingerprint sensor, its fingerprint residues and other spot residual with respect to RF-type fingerprint sensor impact very large, and its investigation depth is no more than the insulating medium that 20um is thick.As China Patent No. ZL021059608 and application number all provide a kind of capacitance type fingerprint reading manner for 201220476953, because the direct contact surface of pointing is only to have the mineral compound of several um to form by thickness to the insulation course between the sensing electrode of sensing array, thereby cause its hydrophobicity, anti-residual, crushing resistance and antistatic property extreme difference.
It will be apparent to those skilled in the art that the electrostatic protection that will reach more than 20KV requires the thickness of the insulating medium on sensor sensing electrode to be greater than 20um.Existing external fingerprint sensor is AUTHENTEC only, FPC and VALIDITY San Ge company have realized RF-type fingerprint collecting, the basic homology of RF-type acquisition principle of AUTHENTEC HeFPCLiang Ge company, as US Patent No. 6512381, realize RF-type fingerprint collecting, can good anti-fingerprint residues and other spots residual, its investigation depth is tens um only also, because a radio-frequency pulse is corresponding, detect one or more fingerprint pixels, poor at its antijamming capability of application scenario that some radio-frequency radiation is stronger.
When this radio-frequency pulse is interfered, this pixel or a plurality of pixel will be interfered.Its use of sensor of VALIDITY company be the typical structure (Chip-on-flex of LCD MODULE, be called for short COF) principle, it can only be slip form that the principle of work of this sensor itself has just limited sensor, and the fingerprint sensor of slidingtype is very poor on user's experience effect, to such an extent as to such sensor can not use widely.
For example, refer to Fig. 1, Fig. 1 is the sensing cell structural representation of the fingerprint sensor of prior art.As shown in the figure, existing sensing cell 1 comprises: the sense capacitance 11 that formed with sensing electrode by finger 10, the edge capacitance 12, amplifier 13 and the reseting switch circuit 14 that by the output electrode of sensing electrode and amplifier, are formed; This sensing cell 1 is by detecting the radiofrequency signal size of handling digital reflex of being sent by radiofrequency signal 15, this signal is further processed by follow-up circuit after capacitance integral amplifying circuit amplifies, according to the difference of sense capacitance 11 values, the radiofrequency signal of varying strength detected, thereby realize fingerprint collecting.When the method is thicker for the Media Ratio between finger 10 and sensing electrode (being greater than 200u), need to proofread and correct sensing cell 1, and it is larger to proofread and correct difficulty, and, the corresponding one or more pixels of a radio-frequency (RF) pulse signal of the method, such radiofrequency signal local sensing cell when being subject to radiation interference will be subject to serious interference.
Therefore, existing fingerprint sensor, no matter be capacitive or the fingerprint sensor of RF-type is all the paddy ridge capacitance difference that detects finger valley line, crestal line and the formation of sensor sensing electrode, for existing domestic fingerprint sensor, the paddy ridge capacitance difference that can detect is in the quantity rank of several fF, the paddy ridge capacitance difference that can detect for existing external fingerprint sensor is in the quantity rank of 0.1fF, and existing domestic and international fingerprint sensor can't meet the specific (special) requirements of mobile device.
Utility model content
In order to solve the problems of the technologies described above, the utility model provides a kind of radio frequency decline electric capacity fingerprint collecting chip and acquisition method thereof, does not affect in the situation of mobile device outward appearance sensor is placed under touch-control face glass and still can senses fingerprint image clearly.The utility model is realized the paddy ridge capacitance difference that can detect below 0.005fF by improving the structure of sensing cell and increasing sensing cell distortion correction circuit, by the fingerprint sensor after improving, can be placed under the contact panel that 0.5mm is thick and still can be sensed fingerprint image clearly.
For achieving the above object, the technical solution of the utility model is as follows:
The radio frequency electric capacity fingerprint collecting chip that declines, comprises L the two-dimentional sensing cell array forming with reference to sensing cell, a M*N sensing cell, in order to produce radiofrequency signal generation circuit, RF driven electrode, sensing cell array control unit, analog to digital conversion array, sensing cell distortion correction circuit, fingerprint image buffer, digital to analog converter, fingerprint image o controller and the image-signal processor of radiofrequency signal; The emission of radio frequency signals that RF driven electrode produces circuit generation by described radiofrequency signal is to the finger that touches fingerprint sensor; Sensing cell array control unit for provide open or turn-off the switching signal of the required power supply of sensing cell biasing and provide sensing cell required discharge and recharge clock signal; Analog to digital conversion array consists of side by side N analog to digital converter, its by described sensing cell array detection to sense capacitance convert fingerprint image gray-scale value to; Sensing cell distortion correction circuit, L the data that collect with reference to sensing cell of usining are proofreaied and correct the deviation between each sensing cell as benchmark; Fingerprint image buffer, it is for storing described fingerprint image data and the sensing cell offset correction data of current conversion; Digital to analog converter, it controls the gain of described analog to digital conversion array; Fingerprint image o controller, in order to transmission fingerprint view data; Image-signal processor, it receives the fingerprint image data that described fingerprint image o controller sends, according to described fingerprint image data, judge its true or false and normally whether and make corresponding processing, wherein, N, M is 2 to 300 integer, and L is the integer that is less than N*M, is directly covered in insulation course on acquisition chip circuit as the dielectric layer of sense capacitance in described sensing cell.
Preferably, described each sensing cell comprises the formed single sense electrode of top-level metallic, sense capacitance dielectric layer, reference capacitance and the activated amplifier etc. by integrated circuit technology; Sense capacitance dielectric layer, its insulation course that is 0.1um～150um by the thickness being directly covered on top-level metallic forms, and described single sense electrode and finger and sense capacitance dielectric layer form single sense electric capacity; Activated amplifier, it is connected to unity gain buffer, and its input connects sensing electrode by switch, and its output connects guarded electrode by switch; By the formed single guarded electrode of the metal level outside integrated circuit technology top-level metallic, described single guarded electrode and single sense electrode form single mask capacitor, described single guarded electrode is by single sense electrode and other electrode isolation, and making the stray capacitance forming with single sense electrode is zero; By the formed single correcting electrode of the arbitrary metal level of integrated circuit technology, described single correcting electrode and single sense electrode form single corrective capacity; The single intensifier electrode being formed by the arbitrary metal level of integrated circuit technology, described single intensifier electrode and single sense electrode form single enhancing electric capacity, strengthen electric capacity and are used for strengthening collection effect; And a plurality of on-off circuits, it controls reference capacitance, sense capacitance, enhancing electric capacity and corrective capacity discharges and recharges and equalizing charge.
Preferably, described sensing cell distortion correction circuit also comprises forward-backward counter array, multiplier battle array, sensing cell deviation statistics circuit and sensing cell offset correction factor counting circuit, wherein, described in described forward-backward counter array computation sensing cell with reference to the deviation of sensing cell; Described sensing cell deviation statistics circuit is added up the mean value of described absolute value of the bias; Described sensing cell offset correction factor counting circuit carries out mapping calculation by the mean value of the numerical value of the input of described digital to analog converter and host computer input and described absolute value of the bias and obtains correction factor; Described multiplier array multiplies each other described deviation and described correction factor, and its Output rusults is as described sensing cell correction for drift data.The method of described mapping calculation is: described correction factor is directly obtained by host computer, and described correction factor directly equals the correction factor that host computer calculates; The method of the host computer calculation correction factor is as follows:
K1=B*N1*E1/H1；
Wherein, K1 is the correction factor that host computer calculates;
B is a fixed coefficient;
N1 is the numerical value of the digital to analog converter input of the described chip that reads by instruction of host computer;
To be host computer read the mean value of described sensing cell and absolute value of the bias with reference to sensing cell by instruction to E1;
H1 is the assembly average of the actual sensed unit deviation by a large amount of described chips acquisitions of test;
Or described correction factor obtains by described chip internal, the computing method of correction factor are as follows:
K2=B*N2*E2/H2;
Wherein, K2 is the correction factor that described chip calculates;
B is a fixed coefficient;
N2 is the numerical value of the digital to analog converter input of described chip;
The sensing cell that described in E2, sensing cell distortion correction circuit calculates and mean value with reference to the absolute value of the bias of sensing cell;
The assembly average that H1 is the actual sensed unit deviation of pass through a large amount of described chips acquisitions of test inputted by host computer;
For achieving the above object, another technical scheme of the present utility model is as follows:
The radio frequency electric capacity fingerprint collecting chip that declines, comprises that L with reference to sensing cell, a M*N two-dimentional sensing cell array that compound sensing cell forms, produce circuit, RF driven electrode, compound sensing cell array control unit, analog to digital conversion array, compound sensing cell distortion correction circuit, fingerprint image buffer, digital to analog converter, fingerprint image o controller and image-signal processor in order to produce the radiofrequency signal of radiofrequency signal; Described compound sensing cell is comprised of a plurality of compound sub-sensing cells; The emission of radio frequency signals that RF driven electrode produces circuit generation by described radiofrequency signal is to the finger that touches fingerprint sensor; Compound sensing cell array control unit, for provide open or turn-off the switching signal of the required power supply of sensing cell biasing and provide sensing cell required discharge and recharge clock signal; Analog to digital conversion array consists of side by side N analog to digital converter, its by described compound sensing cell array detection to sense capacitance convert fingerprint image gray-scale value to; Compound sensing cell distortion correction circuit, L the data that collect with reference to sensing cell of usining are proofreaied and correct the deviation between each sensing cell as benchmark; Fingerprint image buffer, it is for storing described fingerprint image data and the compound sensing cell offset correction data of current conversion; Digital to analog converter, it controls the gain of described analog to digital conversion array; Fingerprint image o controller is in order to transmission fingerprint view data; Image-signal processor receives the fingerprint image data that described fingerprint image o controller sends, according to described fingerprint image data, judge its true or false and normally whether and make corresponding processing, wherein, N is 1 to 150 integer, M is 2 to 300 integer, L is the integer that is less than N*M, is directly covered in insulation course on acquisition chip circuit as the dielectric layer of sense capacitance in described compound sensing cell.
Preferably, described each compound sensing cell comprises the formed N of a top-level metallic sensing electrode, sense capacitance dielectric layer, a N sense capacitance and the multiplexing reference capacitance etc. by integrated circuit technology; Sense capacitance dielectric layer, its insulation course that is 0.1um～150um by the thickness being directly covered on described top-level metallic forms; A described N sensing electrode and finger and sense capacitance dielectric layer form N sense capacitance; By the guarded electrode of the N that metal level forms outside integrated circuit technology top-level metallic, a described N guarded electrode and N sensing electrode form N mask capacitor; N the correcting electrode being formed by the arbitrary metal level of integrated circuit technology, a described N correcting electrode and N sensing electrode form N corrective capacity; By integrated circuit technology N that arbitrary metal level a forms intensifier electrode, a described N intensifier electrode and N sensing electrode form N and strengthen electric capacity, strengthen electric capacity and are used for strengthening collection effect; N organizes on-off circuit; Multiplexing activated amplifier, is connected to multiplexing unity gain buffer, and its input connects N sensing electrode by N switch, and its output connects N guarded electrode by N switch; A described N sensing electrode, sense capacitance dielectric layer, multiplexing reference capacitance, a N mask capacitor, a N corrective capacity, N strengthen electric capacity, N group on-off circuit and multiplexing activated amplifier and form N sub-sensing cell; Wherein, each sub-sensing cell comprises: sensing electrode, sense capacitance dielectric layer, mask capacitor, corrective capacity, one strengthen electric capacity, one group of switch, multiplexing reference capacitance and multiplexing activated amplifier, wherein multiplexing reference capacitance and multiplexing activated amplifier are sharing unit; Described multiplexing reference capacitance and multiplexing activated amplifier are placed on by the below in a described N region that sensing electrode forms or are positioned over the side by a described N region that sensing electrode forms, and described side marginal position is less than 500um from the vertical range of the marginal position in described region.
Preferably, described sensing cell distortion correction circuit also comprises forward-backward counter array, multiplier battle array, sensing cell deviation statistics circuit and sensing cell offset correction factor counting circuit, wherein, described in described forward-backward counter array computation sensing cell with reference to the deviation of sensing cell; Described sensing cell deviation statistics circuit is added up the mean value of described absolute value of the bias; Described sensing cell offset correction factor counting circuit carries out mapping calculation by the mean value of the numerical value of the input of described digital to analog converter and host computer input and described absolute value of the bias and obtains correction factor; Described multiplier array multiplies each other described deviation and described correction factor, and its Output rusults is as described sensing cell correction for drift data.
From technique scheme, can find out, the utility model is residual in order to solve above-mentioned finger, anti-interference, antistatic and investigation depth problem, a kind of radio frequency electric capacity fingerprint collecting chip that declines is provided, purport realizes the micro-capacitance detecting of finger by improving the structure of sensing cell and increasing sensing cell distortion correction circuit on the basis of existing technology, it is by special RF-wise resisting remaining fingerprint, other spot is residual to be disturbed with other radio-frequency radiation, and can avoid static discharge (Electro Static Discharge by improving the investigation depth of sensor, be called for short ESD) effect and sensor is embedded and touched under capacitance plate.
Accompanying drawing explanation
Fig. 1 is the sensing cell electrical block diagram of fingerprint sensor of the prior art
Fig. 2 is the circuit structure diagram that the utility model radio frequency declines in capacitive fingerprint sensor chip embodiment
Fig. 3 is the encapsulating structure diagrammatic cross-section that the utility model radio frequency declines in capacitive fingerprint sensor chip embodiment
Fig. 4 is the sensing cell electrical block diagram that the utility model radio frequency declines in capacitive fingerprint sensor chip embodiment
Fig. 5 is the compound sensing cell electrical block diagram that the utility model radio frequency declines in capacitive fingerprint sensor chip embodiment
[symbol description in figure]
1, the sensing cell of prior art
10, finger
11, the sense capacitance of prior art
12, the edge electric capacity of prior art
13, amplifier
14, reset switch
15, the RF signal that prior art is used
2, the radio frequency electric capacity fingerprint collecting chip that declines
20, sensing cell array
201, sensing cell
202, with reference to sensing cell
21, sensing cell array control unit
22, column ADC array
221, analog to digital converter (ADC)
23., sensing cell distortion correction circuit
24, fingerprint image buffer
25, fingerprint image o controller
26, fingerprint image processor
27, digital to analog converter (DAC)
28, RF signal generating circuit
29, RF driven electrode
3, fingerprint sensor xsect
30, insulated substrate
31, nonconductive adhesive
32a, RF driven electrode
32b, RF driven electrode
33, sensing cell
34, buffering spacer
35, insulation course
40, sense capacitance
401, finger skin corium
402, sensing electrode
410,411,412,413 on-off circuits
420, strengthen electric capacity
421, sensing cell offset correction electric capacity
422, mask capacitor
423, reference capacitance
430,431 power supplys
44, amplifier
45, sensing cell control bus
50a, 50b sense capacitance
501, finger skin corium
502a, 502b sensing electrode
510a, 511a, 512a, 513a, 510b, 511b, 512b, 513b on-off circuit
520a, 520b strengthen electric capacity
521a, 521b sensing cell offset correction electric capacity
522a, 522b mask capacitor
523, multiplexing reference capacitance
530a, 531a, 530b, 531b power supply
54, multiplexing amplifier
55a, 55b sensing cell control bus
Embodiment
Describe in conjunction with the drawings one exemplary embodiment in detail, it is more obvious that These characteristics of the present utility model and advantage will become, and in the accompanying drawings, adopt element like similar Reference numeral representation class between each accompanying drawing.Described accompanying drawing is exemplary rather than draws in proportion.
Below in conjunction with accompanying drawing 2 to 5, embodiment of the present utility model is described in further detail.The utility model will describe by embodiment, but thinking of the present utility model is not restricted to embodiment of the present utility model.
Refer to Fig. 2, Fig. 2 is the decline electrical block diagram of electric capacity fingerprint chip of the utility model radio frequency.As shown in the figure, this radio frequency electric capacity fingerprint chip 2 that declines for example comprises two-dimentional sensing cell array 20(, M*N two dimension sensing cell array), optional a plurality of with reference to sensing cell 202(for example, L with reference to sensing cell), sensing cell array control unit 21, analog to digital conversion (column ADC) array 22, sensing cell distortion correction circuit 23, fingerprint image buffer 24, fingerprint image o controller 25, image-signal processor 26, digital to analog converter 27, radio frequency (RF) signal generating circuit 28 and RF driven electrode 29.Wherein, in encapsulating structure, there is a layer insulating to directly overlay two-dimentional sensing cell array 20 and optional a plurality of with reference on sensing cell 202.Wherein, N, M is 2 to 300 integer, L is the integer that is less than N*M.
In the present embodiment, two dimension sensing cell array 20 is spliced to form by a plurality of sensing cells 201, sensing cell array control unit 21 for provide open or turn-off the switching signal of the required power supply biasing of sensing cell 201 and provide sensing cell 201 required discharge and recharge clock signal; The emission of radio frequency signals that RF driven electrode 29 produces RF signal generating circuit 28 is to the finger that touches fingerprint sensor; Analog to digital conversion array 22 consists of side by side a plurality of analog to digital converters 221, and its sense capacitance that sensing cell array 20 is detected converts fingerprint image gray-scale value to; Sensing cell distortion correction circuit 23, for proofreading and correct the deviation between each sensing cell; Fingerprint image buffer 24 is for the finger print information storing current effective row sensing cell and collect and the deviation between each sensing cell; Fingerprint image processor 26 produces and gathers the required a series of sequential of fingerprint and the finger print information collecting is done to optimization process; Fingerprint image o controller 25 outputs to fingerprint image processor 26 according to the control address of fingerprint image processor 26 inputs by the finger print information collecting; And fingerprint image processor 26 receives the fingerprint image data that described fingerprint image o controller 25 sends, according to described fingerprint image data, judge its true or false and normally whether and make corresponding processing.
Refer to Fig. 3, Fig. 3 is the decline cross-sectional structure schematic diagram of capacitive fingerprint sensor chip of the utility model radio frequency.As shown in the figure, the decline xsect 3 of electric capacity fingerprint collecting chip of a kind of radio frequency that the utility model provides comprises insulation course 35, nonconductive adhesive 31, insulated substrate 30 and RF driven electrode 32a, the 32b on a plurality of sensing cells 33, a plurality of sensing cell.Wherein, this insulated substrate 30 by nonconductive adhesive 31 and insulation course 35 closely sticky with together with, this insulated substrate 30 is usually used as the surface of contact of pointing; In the present embodiment, the thickness of insulated substrate xsect 30 can reach 1mm, and the thickness of nonconductive adhesive xsect 31 is thinned to below 20um as much as possible.In addition, in the present embodiment, can also comprise RF driven electrode 32a, 32b and buffering spacer 34, this RF driven electrode 32a, 32b can be embedded in insulated substrate 30.
It should be noted that, the utility model radio frequency sensing cell circuit structure in capacitive fingerprint sensor chip embodiment that declines, can adopt following two kinds of embodiments.In embodiment mono-, be illustrated in fig. 4 shown below, sensing cell 201 is used a reference capacitance and an amplifier; And in embodiment bis-, be illustrated in fig. 5 shown below, sensing cell 201 is comprised of 2 compound sub-sensing cells, two sub-sensing cells of Fig. 5 share a reference capacitance and an amplifier, the benefit that sensing cell shown in Fig. 5 is compared the sensing cell shown in Fig. 4 is, its amplifier and reference capacitance can be done greatly, and matching is better, and the impact of stray capacitance is less.
[embodiment mono-]
Refer to Fig. 4, Fig. 4 is the sensing cell electrical block diagram that the utility model radio frequency declines in capacitive fingerprint sensor chip embodiment.As shown in the figure, each sensing cell 201 can comprise: the formed single sense electrode 402 of top-level metallic and the sense capacitance dielectric layer that by integrated circuit technology, are formed, this sensed media layer consists of the insulation course on top-level metallic 401, and single sense electrode 401 forms single sense electric capacity 40 with finger and sense capacitance dielectric layer.
In addition, each sensing cell 201 also comprises reference capacitance 423, activated amplifier 44, corrective capacity 421, strengthens electric capacity 420, reference capacitance 423 and on-off circuit 410,411,412,413.Wherein, the single correcting electrode being formed by the arbitrary metal level of integrated circuit technology, this single correcting electrode and single sense electrode form single corrective capacity 421; By the formed single guarded electrode of the metal level outside integrated circuit technology top-level metallic, this single guarded electrode and single sense electrode form single mask capacitor 422; By the arbitrary metal level of integrated circuit technology, form single intensifier electrode, this single intensifier electrode and single sense electrode form single enhancing electric capacity 420; 4 on-off circuits 410,411,412,413 are controlled reference capacitance 423, sense capacitance 40, enhancing electric capacity 420 and corrective capacity 421 and are discharged and recharged and equalizing charge.
In the present embodiment, sensing cell distortion correction circuit 23 also comprises forward-backward counter array, multiplier battle array, sensing cell deviation statistics circuit and sensing cell offset correction factor counting circuit, wherein, sensing cell 201 and deviation with reference to sensing cell 202 described in described forward-backward counter array computation; Described sensing cell deviation statistics circuit is added up the mean value of described absolute value of the bias; Described sensing cell offset correction factor counting circuit carries out mapping calculation by the mean value of the numerical value of the input of described digital to analog converter 27 and host computer input and described absolute value of the bias and obtains correction factor; Described multiplier array multiplies each other described deviation and described correction factor, and its Output rusults is as described sensing cell correction for drift data.The method of described mapping calculation is: described correction factor is directly obtained by host computer, and described correction factor directly equals the correction factor that host computer calculates; The method of the host computer calculation correction factor is as follows:
K1=B*N1*E1/H1；
Wherein, K1 is the correction factor that host computer calculates;
B is a fixed coefficient;
N1 is the numerical value of the digital to analog converter input of the described chip that reads by instruction of host computer;
To be host computer read the mean value of described sensing cell and absolute value of the bias with reference to sensing cell by instruction to E1;
H1 is the assembly average of the actual sensed unit deviation by a large amount of described chips acquisitions of test;
Or described correction factor obtains by described chip internal, the computing method of correction factor are as follows:
K2=B*N2*E2/H2;
Wherein, K2 is the correction factor that described chip calculates;
B is a fixed coefficient;
N2 is the numerical value of the digital to analog converter input of described chip;
The sensing cell that described in E2, sensing cell distortion correction circuit calculates and mean value with reference to the absolute value of the bias of sensing cell;
The assembly average that H1 is the actual sensed unit deviation of pass through a large amount of described chips acquisitions of test inputted by host computer;
According to the circuit of above-mentioned acquisition chip, adopting the radio frequency of the said chip circuit electric capacity fingerprint collecting method that declines is based on frequency signal generating circuit 28, RF driven electrode 29 and the sensing cell with charge pump circuit structure, by charge pump principle, to realize finger print information can specifically comprise the steps: to the conversion of electric signal
Step S1: in the time of on finger is placed on two-dimentional sensing cell array 20, a line sensing cell in the described two-dimentional sensing cell array 20 of described sensing cell array control unit 21 selection is as effective row sensing cell of current collection fingerprint;
Step S2: during described sensing cell array control unit 21 output initialization, the current effective row sensing cell of ordered pair carries out initialization;
Step S3: during described sensing cell array control unit 21 output fingerprint collecting, the current effective row sensing cell of ordered pair carries out fingerprint collecting;
Step S4: the finger print information that the current effective row sensing cell of described sensing cell array control unit 21 output finger print information timing ordered pair collects is proofreaied and correct; Finger print information after current effective row sensing cell is proofreaied and correct is taken away;
Step S5: described sensing cell array control unit 21 selects next line sensing cell as effective row sensing cell of current collection fingerprint, order completes initialization, fingerprint collecting, finger print information correction and fetching finger mark information Four processes, until described sensing cell array control unit selects last column sensing cell as effective row sensing cell of current collection fingerprint, order completes initialization, fingerprint collecting, finger print information correction and fetching finger mark information Four processes.
In the present embodiment, above-mentioned steps S2 is that initialization collection sequential can comprise:
Step S21: described sensing cell array control unit 21 output the first pulse signals are to current effective row sensing cell, described pulse signal is reference capacitance 423 chargings to current effective row sensing cell during pulse width, make the quantity of electric charge that these reference capacitance 423 two ends accumulating values are C1*V1, described C1 is the capacitance of reference capacitance, and described V1 is the magnitude of voltage to reference capacitance charging;
Step S22: described sensing cell array control unit 21 output the second pulse signals are to current effective row sensing cell, the radiofrequency signal that described pulse signal and described radiofrequency signal produce circuit 28 generations is discharged the corrective capacity 421 of current effective row sensing cell, makes the quantity of electric charge at its two ends become zero; Enhancing electric capacity 420 chargings of the current effective row sensing cell of described pulse enable signal, make the quantity of electric charge that its two ends accumulating value is C2*V2, and described C2 is for strengthening the capacitance of electric capacity, and described V2 is for giving the magnitude of voltage that strengthens capacitor charging; The current potential at described pulse enable signal mask capacitor two ends is all V2;
Step S23: described sensing cell array control unit 21 output the 3rd pulse signals are to current effective row sensing cell, described radiofrequency signal produces Partial charge that radiofrequency signal that circuit 28 produces first makes to strengthen electric capacity 420 and transfers on described corrective capacity 421 and make the output of the unity gain buffer of current effective row sensing cell be connected to the guarded electrode of current effective row sensing cell, described the 3rd pulse signal makes described reference capacitance 423, enhancing electric capacity 420 and corrective capacity 421 carry out equalizing charge again, and the quantity of electric charge at described reference capacitance 423 two ends is reduced;
Step S24: the second pulse signal of described sensing cell array control unit 21 output fixed cycles number of times and the 3rd pulse signal are to current effective row sensing cell, described radiofrequency signal produces the radiofrequency signal that circuit 28 produces identical fixed cycles number of times, the second pulse signal of described fixed cycles number of times and the 3rd pulse signal make the voltage difference at reference capacitance 423 two ends of described effective row sensing cell successively reduce with the radiofrequency signal that described radiofrequency signal produces the identical fixed cycles number of times of circuit 28 generations jointly, it is locked that circulation finishes the voltage difference at rear described reference capacitance 423 two ends, described analog to digital conversion array 22 converts described voltage differential signal to the initialization value of current effective row sensing cell simultaneously, wherein, the fixed cycles number of times in initialization procedure can be set to 2 Nth power, and N is 2 to 8 integer,
Step S25: import the initialization value of described current effective row sensing cell into fingerprint image buffer 24, complete the initialization procedure of current effective row sensing cell.
In the present embodiment, above-mentioned steps S3 is that fingerprint collecting sequential can comprise:
Step S31: after initialization sequential finishes, described sensing cell array control unit 21 is exported the first pulse signal again to current effective row sensing cell, described pulse signal is reference capacitance 423 chargings to current effective row sensing cell during pulse width, make described reference capacitance 423 two ends accumulate certain quantity of electric charge, described certain quantity of electric charge can be identical with the initialized quantity of electric charge;
Step S32: described sensing cell array control unit 21 is exported the second pulse signal again to current effective row sensing cell, the radiofrequency signal that described pulse signal and described radiofrequency signal produce circuit 28 generations is discharged the sense capacitance 40 of current effective row sensing cell and corrective capacity 421, make the quantity of electric charge at its two ends become zero, enhancing electric capacity 420 chargings of the current effective row sensing cell of described pulse enable signal, make the quantity of electric charge that its two ends accumulating value is C2*V2, wherein C2 is for strengthening the capacitance of electric capacity, and V2 is for giving the magnitude of voltage that strengthens capacitor charging; The current potential at described pulse enable signal mask capacitor two ends is all V2;
Step S33: described sensing cell array control unit 21 is exported the 3rd pulse signal again to current effective row sensing cell, described radiofrequency signal produces the radiofrequency signal of circuit 28 generations and outwards launches by described RF driven electrode 29, will be in the radiofrequency signal of the generation of finger skin corium and described radiofrequency signal homophase after RF driven electrode 29 described in finger contact, the Partial charge that the radiofrequency signal that described radiofrequency signal produces radiofrequency signal that circuit 28 produces and the generation of described skin corium first makes to strengthen electric capacity 420 jointly transfers on described sense capacitance 40 and corrective capacity 421, described the 3rd pulse signal makes described reference capacitance 423 again, sense capacitance 40, strengthen electric capacity 420 and corrective capacity 421 and carry out equalizing charge, the quantity of electric charge at described reference capacitance 40 two ends is reduced,
Step S34: the second pulse signal of described sensing cell array control unit 21 another fixed cycles number of times of output and the 3rd pulse signal are to current effective row sensing cell, described radiofrequency signal produces the radiofrequency signal of circuit 28 generations and outwards launches the radiofrequency signal of identical fixed cycles number of times by described RF driven electrode 29, the second pulse signal of described fixed cycles number of times and the 3rd pulse signal make the voltage difference at reference capacitance 423 two ends of described effective row sensing cell successively reduce with the radiofrequency signal of identical fixed cycles number of times and the radiofrequency signal of the identical fixed cycles number of times that described finger skin corium produces that described radiofrequency signal produces circuit generation jointly, it is locked that circulation finishes the voltage difference at rear described reference capacitance 423 two ends, simultaneously described analog to digital conversion battle array 22 row convert described voltage differential signal to finger print information that current effective row sensing cell collects, the M power that wherein said fixed cycles number of times is 2, M is 4 to 16 integer,
Step S35: the finger print information that described current effective row sensing cell is collected imports fingerprint image buffer 24 into, completes the fingerprint collecting process of current effective row sensing cell.
In the present embodiment, above-mentioned steps S4 finger print information correction sequential can comprise:
Step S41: current effective row sensing cell is after completing initialization and fingerprint collecting process, sequential is proofreaied and correct in described sensing cell array control unit 21 outputs first, by the initial value of current effective row sensing cell, calculate sensing cell correction for drift data with reference to the initial value of sensing cell, the numerical value of the input of digital to analog converter and host computer input is input to described sensing cell distortion correction circuit, and described sensing cell correction for drift data are stored in fingerprint image impact damper 24;
Step S42: sequential is proofreaied and correct in described sensing cell array control unit output second, and the finger print information that described effective row sensing cell is collected deducts the information in fingerprint after described sensing cell correction for drift data are proofreaied and correct;
Step S43: the information in fingerprint after current effective row sensing cell is proofreaied and correct is stored in described fingerprint image buffer 24, under the control of host computer, the information in fingerprint after described correction is taken away.
[embodiment bis-]
Refer to Fig. 5, Fig. 5 is the compound sensing cell electrical block diagram that the utility model radio frequency declines in capacitive fingerprint sensor chip embodiment.As shown in the figure,
Each compound sensing cell 201 comprises optional a plurality of sub-sensing cell structure; Formed two the sensing electrode 502a of top-level metallic and 502b by integrated circuit technology; Sense capacitance dielectric layer (not shown), it consists of the insulation course on integrated circuit technology top-level metallic, nonconductive adhesive and insulated substrate, and two sensing electrode 502a and 502b and finger skin corium 501 and sense capacitance dielectric layer form sense capacitance 50a and 50b; By other metal electrodes of two sensing electrode 502a and 502b and integrated circuit technology, formed two strengthen electric capacity 520a and 520b, two sensing cell offset correction electric capacity 521a and 521b and two mask capacitor 522a and 522b; Multiplexing reference capacitance 523; The multiplexing amplifier 54 of having chance with; A plurality of on-off circuit 510a, 510b, 511a, 511b, 512a, 512b, 513a and 513b, be used for controlling enhancing electric capacity 520a, sense capacitance 50a, sensing cell corrective capacity 521a and multiplexing reference capacitance 523 and discharge and recharge and equalizing charge, or control enhancing electric capacity 520b, sense capacitance 50b, sensing cell corrective capacity 521b and multiplexing reference capacitance 523 discharge and recharge and equalizing charge.
In the present embodiment, sensing cell distortion correction circuit 23 also comprises forward-backward counter array, multiplier battle array, sensing cell deviation statistics circuit and sensing cell offset correction factor counting circuit, wherein, sensing cell 201 and deviation with reference to sensing cell 202 described in described forward-backward counter array computation; Described sensing cell deviation statistics circuit is added up the mean value of described absolute value of the bias; Described sensing cell offset correction factor counting circuit carries out mapping calculation by the mean value of the numerical value of the input of described digital to analog converter 27 and host computer input and described absolute value of the bias and obtains correction factor; Described multiplier array multiplies each other described deviation and described correction factor, and its Output rusults is as described sensing cell correction for drift data.The method of described mapping calculation is: described correction factor is directly obtained by host computer, and described correction factor directly equals the correction factor that host computer calculates; The method of the host computer calculation correction factor is as follows:
K1=B*N1*E1/H1；
Wherein, K1 is the correction factor that host computer calculates;
B is a fixed coefficient;
N1 is the numerical value of the digital to analog converter input of the described chip that reads by instruction of host computer;
To be host computer read the mean value of described sensing cell and absolute value of the bias with reference to sensing cell by instruction to E1;
H1 is the assembly average of the actual sensed unit deviation by a large amount of described chips acquisitions of test;
Or described correction factor obtains by described chip internal, the computing method of correction factor are as follows:
K2=B*N2*E2/H2;
Wherein, K2 is the correction factor that described chip calculates;
B is a fixed coefficient;
N2 is the numerical value of the digital to analog converter input of described chip;
The sensing cell that described in E2, sensing cell distortion correction circuit calculates and mean value with reference to the absolute value of the bias of sensing cell;
The assembly average that H1 is the actual sensed unit deviation of pass through a large amount of described chips acquisitions of test inputted by host computer;
According to the circuit of above-mentioned acquisition chip, adopt the radio frequency of the said chip circuit electric capacity fingerprint collecting method that declines specifically to comprise the steps:
Step S1 ': when finger 10 is placed on two-dimentional sensing cell array 20, sensing cell array control unit 21 selects the sub-sensing cell of a line sensing cell 201 in two-dimentional sensing cell array as effective row sensing cell of current collection fingerprint;
Step S2 ': during the 21 output initialization of sensing cell array control unit, the current effective row sensing cell of ordered pair carries out initialization;
Step S3 ': during sensing cell array control unit 21 output fingerprint collecting, the current effective row sensing cell of ordered pair carries out fingerprint collecting;
The finger print information that 21 pairs of current effective row sensing cells of step S4 ' sensing cell array control unit collect is proofreaied and correct;
Step S5 ' reads the finger print information after current effective row sensing cell is proofreaied and correct;
Step S6 ' sensing cell array control unit 21 selects another sub-sensing cell of effective row sensing cell as current effective row sensing cell successively, and repeating step S2 '～step S5 ' reads Four processes until complete initialization, fingerprint collecting, finger print information correction and the finger print information of all sub-sensing cells;
Step S7 ' sensing cell array control unit selects the sub-sensing cell of the next line sensing cell in two-dimentional sensing cell array as effective row sensing cell of current collection fingerprint successively, and repeating step S2 '～step S6 ' reads Four processes until complete whole two-dimentional sensing cell array to the initialization of fingerprint, fingerprint collecting, finger print information correction and finger print information.
In the present embodiment, above-mentioned steps S2 ' is that sub-sensing cell initialization collection sequential specifically comprises:
Step S21 ': described sensing cell array control unit 21 output the first pulse signals are to current effective row sensing cell, described pulse signal is multiplexing reference capacitance 523 chargings to current effective row sensing cell during pulse width, make the quantity of electric charge that described multiplexing reference capacitance 523 two ends accumulating values are C1*V1, described C1 is the capacitance of multiplexing reference capacitance, and described V1 is the magnitude of voltage to multiplexing reference capacitance charging;
Step S22 ': described sensing cell array control unit 21 output the second pulse signals are to current effective row sensing cell, the radiofrequency signal that described pulse signal and described radiofrequency signal generation circuit 28 produce makes corrective capacity electric discharge 521a or the 521b of current effective row sensing cell, and the quantity of electric charge at its two ends is gone to zero; The enhancing electric capacity 520a of the current effective row sensing cell of described pulse enable signal or 520b charging, make the quantity of electric charge that its two ends accumulating value is C2*V2, and described C2 is for strengthening the capacitance of electric capacity, and described V2 is for giving the magnitude of voltage that strengthens capacitor charging; The current potential at described pulse enable signal mask capacitor two ends is all V2;
Step S23 ': described sensing cell array control unit 21 output the 3rd pulse signals are to current effective row sensing cell, the radiofrequency signal that described radiofrequency signal produces circuit generation first makes effectively to go the enhancing electric capacity 520a of sub-sensing cell or the Partial charge of 520b to be transferred on the corrective capacity 521a or 521b of described effective row sensing cell, described the 3rd pulse signal makes described multiplexing reference capacitance 523 again, effectively the enhancing electric capacity 520a of the sub-sensing cell of row or 520b and corrective capacity 521a or 521b carry out equalizing charge, the quantity of electric charge at described multiplexing reference capacitance 523 two ends is reduced,
Step S24 ': the second pulse signal of described sensing cell array control unit 21 output fixed cycles number of times and the 3rd pulse signal are to current effective row sensing cell, described radiofrequency signal produces the radiofrequency signal that circuit 28 produces identical fixed cycles number of times, the second pulse signal of described fixed cycles number of times and the 3rd pulse signal make the voltage difference at multiplexing reference capacitance 523 two ends of described effective row sensing cell successively reduce with the radiofrequency signal that described radiofrequency signal produces the identical fixed cycles number of times of circuit generation jointly, it is locked that circulation finishes the voltage difference at rear described multiplexing reference capacitance 523 two ends, described analog to digital conversion array 22 converts described voltage differential signal to the initialization value of current effective row sensing cell simultaneously, wherein, the fixed cycles number of times in initialization procedure can be set to 2 Nth power, and N is 2 to 8 integer,
Step S25 ': import the initialization value of described current effective row sensing cell into described fingerprint image buffer 24, complete the initialization procedure of current effective row sensing cell.
In the present embodiment, above-mentioned steps S3 ' is that sub-sensing cell fingerprint collecting sequential specifically comprises:
Step S31 ': after initialization sequential finishes, described sensing cell array control unit 21 is exported the first pulse signal again to current effective row sensing cell, this pulse signal is multiplexing reference capacitance 523 chargings to current effective row sensing cell during pulse width, make described multiplexing reference capacitance 523 two ends accumulate certain quantity of electric charge, these quantities of electric charge can be identical with the initialized quantity of electric charge;
Step S32 ': described sensing cell array control unit 21 is exported the second pulse signal again to current effective row sensing cell, the radiofrequency signal that described pulse signal and described radiofrequency signal generation circuit 28 produce makes sense capacitance 50a or 50b and corrective capacity 521a or the 521b electric discharge of current effective row sensing cell, the quantity of electric charge at its two ends is gone to zero, the enhancing electric capacity 520a of the current effective row sensing cell of described pulse enable signal or 520b charging, make the quantity of electric charge that its two ends accumulating value is C2*V2, wherein C2 is for strengthening the capacitance of electric capacity, V2 is for giving the magnitude of voltage that strengthens capacitor charging, the current potential at described pulse enable signal mask capacitor two ends is all V2,
Step S33 ': described sensing cell array control unit 21 is exported the 3rd pulse signal again to current effective row sensing cell, described radiofrequency signal produces the radiofrequency signal of circuit 28 generations and outwards launches by described RF driven electrode 29, will be in the radiofrequency signal of the generation of finger skin corium and described radiofrequency signal homophase after RF driven electrode 29 described in finger contact, the radiofrequency signal that described radiofrequency signal produces radiofrequency signal that circuit 28 produces and the generation of described skin corium first makes effectively to go the Partial charge of the enhancing electric capacity of sub-sensing cell to be transferred on the sense capacitance 50a or 50b and corrective capacity 521a or 521b of described effective row sensing cell jointly, described the 3rd pulse signal makes described multiplexing reference capacitance 523 again, sense capacitance 50a or 50b, strengthen electric capacity 520a or 520b and corrective capacity 521a or 521b and carry out equalizing charge, the quantity of electric charge at described multiplexing reference capacitance 523 two ends is reduced,
Step S34 ': the second pulse signal of described sensing cell array control unit 21 another fixed cycles number of times of output and the 3rd pulse signal are to current effective row sensing cell, described radiofrequency signal produces the radiofrequency signal of circuit 28 generations and outwards launches the radiofrequency signal of identical fixed cycles number of times by described RF driven electrode 29, the second pulse signal of described fixed cycles number of times and the 3rd pulse signal make the voltage difference at multiplexing reference capacitance 523 two ends of described effective row sensing cell successively reduce with the radiofrequency signal of identical fixed cycles number of times and the radiofrequency signal of the identical fixed cycles number of times that described finger skin corium produces that described radiofrequency signal produces circuit generation jointly, it is locked that circulation finishes the voltage difference at rear described multiplexing reference capacitance 523 two ends, described analog to digital conversion array 22 converts described voltage differential signal to finger print information that current effective row sensing cell collects simultaneously, the M power that wherein said fixed cycles number of times is 2, M is 4 to 16 integer,
Step S35 ': the finger print information that described current effective row sensing cell is collected imports fingerprint image buffer 24 into, completes the fingerprint collecting process of current effective row sensing cell.
In the present embodiment, above-mentioned steps S4 ' is that finger print information correction sequential specifically comprises:
Step S41 ': current effective row sensing cell is after completing initialization and fingerprint collecting process, sequential is proofreaied and correct in described sensing cell array control unit 21 outputs first, by the initial value of current effective row sensing cell 201, calculate sub-sensing cell correction for drift data with reference to the initial value of sensing cell 202, the numerical value of the input of described digital to analog converter 27 and host computer input is input to described sensing cell distortion correction circuit 23, and described sub-sensing cell correction for drift data are stored in fingerprint image impact damper;
Step S42 ': sequential is proofreaied and correct in described sensing cell array control unit 21 outputs second, and the finger print information that described effective row sensing cell is collected deducts the information in fingerprint after described sub-sensing cell correction for drift data are proofreaied and correct;
Step S43 ': the information in fingerprint after current effective row sensing cell is proofreaied and correct is stored in described fingerprint image buffer 24, and the information in fingerprint under the control of host computer after described correction is taken away.
Above-described is only preferred embodiment of the present utility model; described embodiment is not in order to limit scope of patent protection of the present utility model; therefore the equivalent structure that every utilization instructions of the present utility model and accompanying drawing content are done changes, and in like manner all should be included in protection domain of the present utility model.
Claims (6)
1. the radio frequency electric capacity fingerprint collecting chip that declines, is characterized in that, comprising:
L with reference to sensing cell;
M*N the two-dimentional sensing cell array that sensing cell forms;
Radiofrequency signal produces circuit, in order to produce radiofrequency signal;
RF driven electrode, its emission of radio frequency signals that described radiofrequency signal is produced to circuit generation is to the finger that touches fingerprint sensor; Also comprise:
Sensing cell array control unit, for provide open or turn-off the switching signal of the required power supply of sensing cell biasing and provide sensing cell required discharge and recharge clock signal;
Analog to digital conversion array, consists of side by side N analog to digital converter, its by described sensing cell array detection to sense capacitance convert fingerprint image gray-scale value to;
Sensing cell distortion correction circuit, L the data that collect with reference to sensing cell of usining are proofreaied and correct the deviation between each sensing cell as benchmark;
Fingerprint image buffer, it is for storing described fingerprint image data and the sensing cell offset correction data of current conversion;
Digital to analog converter, it controls the gain of described analog to digital conversion array;
Fingerprint image o controller, in order to transmission fingerprint view data;
Image-signal processor, it receives the fingerprint image data that described fingerprint image o controller sends, according to described fingerprint image data, judge its true or false and normally whether and make corresponding processing, wherein, N, M is 2 to 300 integer, and L is the integer that is less than N*M, is directly covered in insulation course on acquisition chip circuit as the dielectric layer of sense capacitance in described sensing cell.
2. the radio frequency according to claim 1 electric capacity fingerprint collecting chip that declines, is characterized in that, described each sensing cell comprises:
The formed single sense electrode of top-level metallic by integrated circuit technology;
Sense capacitance dielectric layer, its insulation course that is 0.1um～150um by the thickness being directly covered on top-level metallic forms, and described single sense electrode and finger and sense capacitance dielectric layer form single sense electric capacity;
Reference capacitance;
Activated amplifier, it is connected to unity gain buffer, and its input connects sensing electrode by switch, and its output connects guarded electrode by switch;
By the formed single guarded electrode of the metal level outside integrated circuit technology top-level metallic, described single guarded electrode and single sense electrode form single mask capacitor;
The single correcting electrode being formed by the arbitrary metal level of integrated circuit technology, described single correcting electrode and single sense electrode form single corrective capacity;
The single intensifier electrode being formed by the arbitrary metal level of integrated circuit technology, described single intensifier electrode and single sense electrode form single enhancing electric capacity, strengthen electric capacity and are used for strengthening collection effect; And
A plurality of on-off circuits, it controls reference capacitance, sense capacitance, enhancing electric capacity and corrective capacity discharges and recharges and equalizing charge.
3. the radio frequency according to claim 1 electric capacity fingerprint collecting chip that declines, it is characterized in that, described sensing cell distortion correction circuit also comprises forward-backward counter array, multiplier battle array, sensing cell deviation statistics circuit and sensing cell offset correction factor counting circuit, wherein
Described in described forward-backward counter array computation sensing cell with reference to the deviation of sensing cell;
Described sensing cell deviation statistics circuit is added up the mean value of described absolute value of the bias;
Described sensing cell offset correction factor counting circuit carries out mapping calculation by the mean value of the numerical value of the input of described digital to analog converter and host computer input and described absolute value of the bias and obtains correction factor;
Described multiplier array multiplies each other described deviation and described correction factor, and its Output rusults is as described sensing cell correction for drift data.
4. the radio frequency electric capacity fingerprint collecting chip that declines, is characterized in that, comprising:
L with reference to sensing cell;
M*N the two-dimentional sensing cell array that compound sensing cell forms; Described compound sensing cell is comprised of two compound sub-sensing cells;
Radiofrequency signal produces circuit, in order to produce radiofrequency signal;
RF driven electrode, its emission of radio frequency signals that described radiofrequency signal is produced to circuit generation is to the finger that touches fingerprint sensor; Also comprise:
Compound sensing cell array control unit, for provide open or turn-off the switching signal of the required power supply of sensing cell biasing and provide sensing cell required discharge and recharge clock signal;
Analog to digital conversion array, consists of side by side N analog to digital converter, its by described compound sensing cell array detection to sense capacitance convert fingerprint image gray-scale value to;
Compound sensing cell distortion correction circuit, L the data that collect with reference to sensing cell of usining are proofreaied and correct the deviation between each sensing cell as benchmark;
Fingerprint image buffer, it is for storing described fingerprint image data and the compound sensing cell offset correction data of current conversion;
Digital to analog converter, it controls the gain of described analog to digital conversion array;
Fingerprint image o controller, in order to transmission fingerprint view data;
Image-signal processor, it receives the fingerprint image data that described fingerprint image o controller sends, according to described fingerprint image data, judge its true or false and normally whether and make corresponding processing, wherein, N is 1 to 150 integer, M is 2 to 300 integer, and L is the integer that is less than N*M, is directly covered in insulation course on acquisition chip circuit as the dielectric layer of sense capacitance in described compound sensing cell.
5. the radio frequency according to claim 4 electric capacity fingerprint collecting chip that declines, is characterized in that,
Described each compound sensing cell comprises:
The formed N of a top-level metallic sensing electrode by integrated circuit technology;
Sense capacitance dielectric layer, its insulation course that is 0.1um～150um by the thickness being directly covered on described top-level metallic forms;
A described N sensing electrode and finger and sense capacitance dielectric layer form N sense capacitance;
Multiplexing reference capacitance;
By the guarded electrode of the N that metal level forms outside integrated circuit technology top-level metallic, a described N guarded electrode and N sensing electrode form N mask capacitor;
N the correcting electrode being formed by the arbitrary metal level of integrated circuit technology, a described N correcting electrode and N sensing electrode form N corrective capacity;
By integrated circuit technology N that arbitrary metal level a forms intensifier electrode, a described N intensifier electrode and N sensing electrode form N and strengthen electric capacity, strengthen electric capacity and are used for strengthening collection effect;
N organizes on-off circuit;
Multiplexing activated amplifier, is connected to multiplexing unity gain buffer, and its input connects N sensing electrode by N switch, and its output connects N guarded electrode by N switch;
A described N sensing electrode, sense capacitance dielectric layer, multiplexing reference capacitance, a N mask capacitor, a N corrective capacity, N strengthen electric capacity, N group on-off circuit and multiplexing activated amplifier and form N sub-sensing cell; Wherein, each sub-sensing cell comprises: sensing electrode, sense capacitance dielectric layer, mask capacitor, corrective capacity, one strengthen electric capacity, one group of switch, multiplexing reference capacitance and multiplexing activated amplifier, wherein multiplexing reference capacitance and multiplexing activated amplifier are sharing unit;
Described multiplexing reference capacitance and multiplexing activated amplifier are placed on by the below in a described N region that sensing electrode forms or are positioned over the side by a described N region that sensing electrode forms, and described side marginal position is less than 500um from the vertical range of the marginal position in described region.
6. the radio frequency according to claim 4 electric capacity fingerprint collecting chip that declines, it is characterized in that, described sensing cell distortion correction circuit also comprises forward-backward counter array, multiplier battle array, sensing cell deviation statistics circuit and sensing cell offset correction factor counting circuit, wherein
Described in described forward-backward counter array computation sensing cell with reference to the deviation of sensing cell;
Described sensing cell deviation statistics circuit is added up the mean value of described absolute value of the bias;
Described sensing cell offset correction factor counting circuit carries out mapping calculation by the mean value of the numerical value of the input of described digital to analog converter and host computer input and described absolute value of the bias and obtains correction factor;
Described multiplier array multiplies each other described deviation and described correction factor, and its Output rusults is as described sensing cell correction for drift data.
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| CN201420141710.1U CN203799390U (en) | 2014-03-27 | 2014-03-27 | Radiofrequency micro-capacitance fingerprint collecting chip |
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| CN103870817A (en) * | 2014-03-27 | 2014-06-18 | 成都费恩格尔微电子技术有限公司 | Radio-frequency micro-capacitance fingerprint acquisition chip and method |
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Effective date of registration: 20141212 Address after: 1, No. 262, No. 2, 610041 floor, No. 1338, Tianfu Road, Chengdu hi tech Zone, Sichuan Patentee after: CHENGDU FEIENGEER MICROELECTRONICS TECHNOLOGY CO., LTD. Patentee after: CHENGDU WEIGUANG CURRENT COLLECTION SCIENCE & TECHNOLOGY CO., LTD. Address before: 1, No. 262, No. 2, 610041 floor, No. 1338, Tianfu Road, Chengdu hi tech Development Zone, Sichuan, Chengdu Patentee before: CHENGDU FEIENGEER MICROELECTRONICS TECHNOLOGY CO., LTD. |
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Granted publication date: 20140827 Effective date of abandoning: 20190405 |
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| AV01 | Patent right actively abandoned |
Granted publication date: 20140827 Effective date of abandoning: 20190405 |
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| AV01 | Patent right actively abandoned | ||
| AV01 | Patent right actively abandoned |