CN109753860A - Biometric image reading device in display area - Google Patents
Biometric image reading device in display area Download PDFInfo
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- CN109753860A CN109753860A CN201711157658.3A CN201711157658A CN109753860A CN 109753860 A CN109753860 A CN 109753860A CN 201711157658 A CN201711157658 A CN 201711157658A CN 109753860 A CN109753860 A CN 109753860A
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- 238000012360 testing method Methods 0.000 claims abstract description 21
- 238000006243 chemical reaction Methods 0.000 claims abstract description 15
- 238000012545 processing Methods 0.000 claims abstract description 15
- 239000011159 matrix material Substances 0.000 claims abstract description 4
- 230000003068 static effect Effects 0.000 claims description 49
- 230000005611 electricity Effects 0.000 claims description 2
- 230000035945 sensitivity Effects 0.000 description 20
- 230000006698 induction Effects 0.000 description 17
- XLOMVQKBTHCTTD-UHFFFAOYSA-N Zinc monoxide Chemical compound [Zn]=O XLOMVQKBTHCTTD-UHFFFAOYSA-N 0.000 description 10
- 230000003321 amplification Effects 0.000 description 9
- 238000001514 detection method Methods 0.000 description 9
- 238000003199 nucleic acid amplification method Methods 0.000 description 9
- 239000011241 protective layer Substances 0.000 description 7
- 238000000034 method Methods 0.000 description 5
- 239000011787 zinc oxide Substances 0.000 description 5
- 239000000126 substance Substances 0.000 description 3
- GYHNNYVSQQEPJS-UHFFFAOYSA-N Gallium Chemical compound [Ga] GYHNNYVSQQEPJS-UHFFFAOYSA-N 0.000 description 2
- 239000006059 cover glass Substances 0.000 description 2
- 238000013461 design Methods 0.000 description 2
- 229910052733 gallium Inorganic materials 0.000 description 2
- 229910052738 indium Inorganic materials 0.000 description 2
- APFVFJFRJDLVQX-UHFFFAOYSA-N indium atom Chemical compound [In] APFVFJFRJDLVQX-UHFFFAOYSA-N 0.000 description 2
- MRNHPUHPBOKKQT-UHFFFAOYSA-N indium;tin;hydrate Chemical compound O.[In].[Sn] MRNHPUHPBOKKQT-UHFFFAOYSA-N 0.000 description 2
- 241000208340 Araliaceae Species 0.000 description 1
- 235000005035 Panax pseudoginseng ssp. pseudoginseng Nutrition 0.000 description 1
- 235000003140 Panax quinquefolius Nutrition 0.000 description 1
- 230000033228 biological regulation Effects 0.000 description 1
- 239000013078 crystal Substances 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
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- AMGQUBHHOARCQH-UHFFFAOYSA-N indium;oxotin Chemical compound [In].[Sn]=O AMGQUBHHOARCQH-UHFFFAOYSA-N 0.000 description 1
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Classifications
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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
-
- 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
- G06V40/1347—Preprocessing; Feature extraction
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03K—PULSE TECHNIQUE
- H03K17/00—Electronic switching or gating, i.e. not by contact-making and –breaking
- H03K17/94—Electronic switching or gating, i.e. not by contact-making and –breaking characterised by the way in which the control signals are generated
- H03K17/96—Touch switches
- H03K17/962—Capacitive touch switches
Abstract
According to an embodiment, the present invention provides the biometric image reading device in a kind of display area, including multiple pixels to constitute the matrix shape configuration of multiple row and columns, it and include: picture element signal processing circuit, conversion is amplified respectively to the first output electric current and the second output electric current to export the first voltage value and second voltage value, above-mentioned first output electric current is exported from the first pixel and is added by the signal based on test object object with the signal based on noise, and above-mentioned second output electric current is exported from the second pixel and including the signal based on noise；And Analog-digital Converter portion, difference is carried out to above-mentioned the first voltage value and second voltage value to digitize.
Description
Technical field
The present invention relates to image read-outs, are related in more detail, and the influence based on noise can be made in display area
Minimize and improve the biometric image reading device of sensitivity.
Background technique
Image read-out using the property of the semiconductor with light reaction come screenshot image, or utilize image read-out
Included in multiple pixels and test object object relationship in the electrical characteristics that are formed carry out screenshot image.
With recently about security protection the problem of attention rate improve, this image read-out be also used in personal verification use
Fingerprint induction.Therefore, it is necessary to installations diagram on the personal portables such as the equipment, such as smart phone, tablet computer of fingerprint induction
As reading device.
On the other hand, in the electronic equipments such as smart phone, tablet computer, because of the demand and design for large area display
Demand etc., be configured at display area in order to which the image read-out of fingerprint induction will be used for recently and make an effort.
In the case, due to configuring thicker protective layer, such as cover glass on the top of image read-out
(cover glass), therefore the distance between the test object object of upper part and image read-out become remote, image read-out
Each pixel and the relationship of test object object in the size of electrical characteristics that is formed become smaller.
If it exists in the case where noise caused by external disturbance, the size of noise and each pixel of image read-out are defeated
The size between signal out is similar, causes to be difficult to detect accurate image.
Summary of the invention
The present invention is as described above for solving the problems, such as, the object of the present invention is to provide minimize the influence of noise
And the image read-out that sensitivity improves.
One embodiment of the invention for reaching above-mentioned purpose provides a kind of image read-out, including multiple to constitute
Multiple pixels of the matrix shape configuration of row and column, and include: picture element signal processing circuit, it is defeated to the first output electric current and second
Electric current amplifies conversion respectively to export the first voltage value and second voltage value out, and above-mentioned first exports electric current from the first pixel
It exports and is added by the signal based on test object object with the signal based on noise, above-mentioned second exports electric current from the second picture
Element exports and including the signal based on noise；And Analog-digital Converter portion, to above-mentioned the first voltage value and second voltage value into
Row difference is digitized.
Above-mentioned second pixel can be at least one pixel for being configured at outermost in above-mentioned multiple pixels.
Above-mentioned picture element signal processing circuit may include quantity signal deteching circuit identical with the quantity of above-mentioned column.
Above-mentioned signal deteching circuit can include: amplifier, first input end are connected with above-mentioned first pixel, the second input
End is selectively connected with above-mentioned second pixel；First feedback static capacity, is connected to the first input end of above-mentioned amplifier
Between the first output end；And the second feedback static capacity, it is connected to the second input terminal of above-mentioned amplifier and is exported with second
Between end.
Reference voltage can be selectively supplied to the second input terminal of above-mentioned amplifier.
The first output end and second output terminal of above-mentioned amplifier can be connected respectively with multiplexer.
It above-mentioned Analog-digital Converter portion can be defeated to the first of the above-mentioned amplifier being sequentially output by above-mentioned multiplexer
End signal and second output terminal signal carry out difference to be digitized out.
Above-mentioned image read-out may also include control unit, and above-mentioned control unit changes the big of above-mentioned first feedback static capacity
Small, the second feedback static capacity size, the first feedback static capacity by above-mentioned first output electric current charging time and the
At least one of the time that two feedback static capacities are charged by above-mentioned second output electric current.
Above-mentioned control unit can based on the above-mentioned first output size of electric current, the working condition of above-mentioned amplifier, from multiple pictures
At least one of deviation between multiple above-mentioned first output electric currents of element output, to execute above-mentioned change work.
According to an embodiment, in image read-out, from each pixel output signal to the output signal based on noise
Difference is carried out, therefore can be realized image detection not affected by noise.
Also, according to an embodiment, in image read-out, putting for the output signal for amplifying each pixel can be changed
The characteristic of big device, therefore high-resolution image detection can be realized in a variety of contexts.
Detailed description of the invention
Fig. 1 is the attached drawing for showing the structure of image read-out of one embodiment of the invention.
Fig. 2 is the attached drawing of the structure for the unit pixel being arranged in the image read-out for show one embodiment of the invention.
Fig. 3 be show the sensitivity improving circuit of the output signal processing circuit of one embodiment of the invention structure it is attached
Figure.
Fig. 4 is gate source voltage and output electric current in the unit pixel for show the image read-out of one embodiment of the invention
Between relationship chart.
Specific embodiment
Hereinafter, the embodiment of the present invention is described in detail referring to attached drawing, to make the common skill of fields of the present invention
Art personnel are easy to implement.The present invention can by it is a variety of it is different in the form of implement, therefore the present invention is not limited to reality described herein
Apply example.Also, it is explicitly stated in order to be carried out to the present invention, the part unrelated with explanation of the invention is omitted in the accompanying drawings,
Throughout the manual, identical appended drawing reference is assigned to same or similar structural element.Also, it is shown in the accompanying drawings each
The size or thickness of structure are easy for the arbitrary size or thickness of explanation, and the invention is not limited to illustrated contents.
Also, when throughout the manual, certain a part is with another part " being connected ", not only including " being directly connected to "
Situation, and the case where there are other component " being indirectly connected with " between being included therein.
Hereinafter, the embodiment of the present invention is described in detail with reference to attached drawing.
Fig. 1 is the attached drawing for showing the structure of image read-out of one embodiment of the invention.
Referring to Fig.1, image read-out according to the embodiment may include sensor panel 100, power supply voltage supplying portion 200
And picture element signal reading part 300.
Sensor panel 100 using multiple pixels 110 of the matrix shape of m × n (m, n is natural numbers) configuration by being constituted.It is more
A pixel 110 respectively with a scan line SL1, SL2, SL3 ..., SLm and read line RL1, RL2 ..., RLn is connected
It connects.
To scan line SL1, SL2, SL3 ..., the particular scan SL1 in SLm supply scanning signal, then with the scanning
The more than one pixel 110 that line SL1 is connected is started to work.Work later to pixel 110 is described in detail.
According to the output signal of the work output of pixel 110 by read line RL1, RL2 ..., RLn be transferred to signal
Reading part 300.
Each read line RL1, RL2 ..., one end of RLn be connected with power supply voltage supplying portion 200, the other end and letter
Number reading part 300 is connected.
Signal-obtaining portion 300 may include picture element signal processing circuit 310, multiplexing portion 320, Analog-digital Converter portion
330。
Base of the output of picture element signal processing circuit 310 as the noise remove work executed by Analog-digital Converter portion 330
The signal of plinth will later be described in detail this.On the other hand, picture element signal processing circuit 310 may include low-pass filtering
Device (low pass filter) etc. removes work for the high-frequency noise of signal exported from each pixel 110 to execute.
In ideal conditions, from read line RL1, RL2 ..., RLn export signal only by sensor panel 100
Top test object influence, however actually also influenced by external disturbance.That is, from each read line (RL1,
RL2 ..., RLbn) output signal be that the signal based on pure test object is added with the signal of the noise based on external disturbance
Form.
Picture element signal processing circuit 310 in order to from each read line RL1, RL2 ..., RLn export signal in offset
It is defeated to execute the read line (RL1, RLn) offset and be connected from the benchmark pixel 111 with the influence of not object under inspection for noise signal
The work of signal out.Said reference pixel 111 can be the region not connected with test object in sensor panel 100, example
It such as can be more than one pixel for being configured at the outside of effective coverage (active area) of sensor panel 100.
On the other hand, picture element signal processing circuit 310 can execute the function of changing the gain of amplifier, to prevent in it
The saturation of amplifier included by portion.
It will be explained below the detailed operation of picture element signal processing circuit 310.
Multiplexing portion 320, multiplexing portion are input to by multiple signals that picture element signal processing circuit 310 exports
320 are sequentially output multiple signal to Analog-digital Converter portion 330.
Analog-digital Converter portion 330 comes inputted signal digitlization with the final output of picture element signal reading part 300
Signal output.
Fig. 2 is the attached drawing for showing the structure of unit pixel of one embodiment of the invention.
Referring to Fig. 2, according to the unit pixel 110 of an embodiment can include: sensor mat SP, with test object object (for example,
Fingerprint) relationship in formed induction static capacity Cs；The first transistor T1 makes data line DL be connected or disconnect with sensor mat SP
Connection；Second transistor T2 exports the current signal of the current potential according to sensor mat SP.
The first electrode of the first transistor T1 is connected with scan line SL, and second electrode is connected with data line DL, third
Electrode is connected with charge rest capacity C a and sensor mat SP.Above-mentioned first electrode can be gate electrode, second electrode and the
Three electrodes can be respectively source electrode (either drain electrode) and drain electrode (or source electrode).
The first electrode of second transistor T2 is connected with charge rest capacity C a and sensor mat SP, second electrode and Fig. 1
Shown in the supply voltage VDD input terminal in power supply voltage supplying portion 200 be connected, third electrode is believed by read line RL and pixel
Number reading part 300 is connected.Above-mentioned first electrode can be gate electrode, and second electrode and third electrode can be respectively drain electrode
Electrode (either source electrode) and source electrode (or drain electrode).Hereinafter, using second transistor T2 as n-type transistor and
Two electrodes and third electrode are respectively to be illustrated in case where drain electrode and source electrode.
The third electrode of one end of charge rest capacity C a and the first transistor T1, sensor mat SP and second transistor T2
First electrode is connected, and the other end is connected with ground potential.Also, regulation current potential Vd is supplied to data line DL.
It constitutes and display panel is configured at according to the unit pixel 110 of the sensor panel 100 (referring to Fig.1) of an embodiment
On (not shown), the image quality deterioration of display panel, sensor panel 100 should be made of transparent or semitransparent substance in order to prevent.
Therefore, the sensor mat SP of unit pixel 110, transistor T1, T2, scan line SL, data line DL, read line RL are substantially to answer
It is made of transparent substance.As an example, transistor T1, T2 can be by using indium gallium zinc oxide (IGZO, Indium Gallium
Zinc Oxide), zinc oxide (ZnO, Zinc Oxide), the oxides such as tin indium oxide (ITO, Indium Tin Oxide) crystalline substance
Body Guan Shixian, sensor mat SP, scan line SL, data line DL, read line RL can also be by tin indium oxide (ITO, Indium Tin
) etc. Oxide oxides constitute substantially to realize in a transparent manner.
Hereinafter, being illustrated to the work of the unit pixel 110 according to an embodiment.
If sensor panel 100 is in contact with test object object, induction is formed between sensor mat SP and test object object
Static capacity Cs.
At this point, starting to supply scanning signal to scan line SL, then the first transistor T1 is converted to opening (ON) state, in number
According to streaming current Ia between line DL and first node N1.The electric current fills charge rest capacity C a and induction static capacity Cs
Electricity, with time going by, the current potential V1 of first node N1 rise.
After the stipulated time obtains stabilisation, interrupts to scan line SL and supply scanning signal, then the first transistor T1
It is converted to close off (OFF) state.The first transistor T1 is maintained open time of state as t0, then the current potential of first node N1
V1 is represented by as follows.
V1 (t0)=Ia (t0)/(Ca+Cs)
Referring to above-mentioned mathematical expression it is found that the current potential V1 of first node N1 and the size of induction static capacity Cs are inversely proportional.
The current potential V1 of first node N1 is the first electrode of second transistor T2, that is, the current potential of gate electrode (G), therefore
The variation of the current potential V1 of first node N1 leads to the variation of the output electric current Id size of second transistor T2.Second transistor T2 tool
There is intrinsic current-voltage (I-V) characteristic.According to the I-E characteristic, the variation of the gate source voltage of specific sections causes greatly
Output electric current Id size variation.
That is, output electric current Id is different according to the gate source voltage of second transistor T2.In other words, the big of electric current Id is exported
The small current potential V1 according to first node N1 and it is different, as described above, the current potential V1 of first node N1 according to induction static capacity Cs
Size and it is different.Therefore, the section jumpy for the gate source voltage of second transistor T2 electric current Id is being exported, even if the
There is small variation in the current potential V1 of one node N1, can also be by output electric current Id with its variation of high sensitivity detection.
In the case where test object object is fingerprint, the case where sensor mat SP connects with the ridge (Rigde) of fingerprint and with finger
The induction static capacity Cs that the paddy (Valley) of line is respectively formed in the case where connecting is different.Also, therefore, sensor mat SP institute
The size of output electric current Id in the pixel 110 of configuration is also different.It therefore, can be from the ridge of fingerprint and the small electrical property difference of paddy
The difference that the value of output electric current Id is obtained with high sensitivity, it is possible thereby to obtain the figure for the fingerprint on sensor panel 100
Picture.
Fig. 2 only shows the first transistor T1 utilized to the selection of pixel and picture element signal amplifies and export institute's benefit
Second transistor T2, however may also include multiple transistors of the addition for executing additional conversion function.
Recently, finger print detection device be laminated on display panel or with the trend of being integrally formed of display panel, refer to as a result,
It may be configured with the protective layer (not shown) of thicker thickness in line detection device.
If the thickness of protective layer thickens, be formed in the size of the induction static capacity Cs between fingerprint and sensor mat SP with
Its thickness inversely becomes smaller, in this case, be formed in induction static capacity Cs between sensor mat SP and the ridge of fingerprint,
The difference being formed between the induction static capacity Cs between sensor mat SP and the paddy of fingerprint becomes smaller, and connects in pixel 110 with ridge
In the case where exported output electric current Id size, connect with paddy in the case where exported output electric current Id difference also become
It is small.
Also, the grid in the I-E characteristic of second transistor T2 stated above, only in second transistor T2
Source voltage is in optimum range, can just be become larger for the variation of the output electric current Id of fine variation, however according to protective layer
Influence, the gate source voltage of second transistor T2 is likely to be present in outside the optimum range.In the case, for second transistor
The variable quantity of the output electric current Id of the gate source voltage variation of T2 becomes smaller, and leads to the sensitivity for being difficult to ensure fingerprint sensor.
On the other hand, sensor panel is provided with multiple pixels, does not can avoid the distribution of occurrence features in process
(dispersion).Distribution because of this characteristic etc. influences, it may occur that the inhomogeneities of the characteristic of each pixel.In this situation
Under, the gate source voltage of second transistor T2 may exceed optimum range in partial pixel, the difference of the output electric current Id in each pixel
It is different less in the case where, cause fingerprint incude sensitivity decline the problem of.
Also, when fingerprint detection, because external environment influence or be formed in pixel 110 internal circuit parasitic direct capacitance
The influence of amount, and increase noise in the output electric current Id of pixel 110, if the case where connecting the case where connecting with ridge and with paddy
Increase noise in the case that output electric current Id size is little, is then likely difficult to distinguish ridge and the paddy of fingerprint.
The embodiment of the present invention to solve the above-mentioned problems, executes from the output signal of pixel 110 and offsets noise signal
Work and the work for improving sensitivity.
Fig. 3 is the attached drawing for showing the structure of output signal processing circuit of the embodiment of the present invention.
Fig. 3 is to show to change in the image read-out according to an embodiment with the read line RL sensitivity being connected
The attached drawing of kind circuit 311, this sensitivity improving circuit 311 are set to each reading in picture element signal processing circuit 310
Line.That is, sensitivity improving circuit 311 is also provided with when the read line in the image read-out of an embodiment is provided with n
There are n.
In sensitivity improving circuit 311, first input end IN1 is connected with specific read line RL, the second input terminal IN2 with
Virtual channel DC is connected, and amplifies the signal of above-mentioned first input end IN1 and to export to the first output end OUT1, makes second defeated
Enter to hold the signal amplification of IN2 to export to second output terminal OUT2.
The first feedback static capacity is connected between the first input end IN1 and the first output end OUT1 of amplifier FEA
Cfb1 is connected with the second feedback static capacity Cfb2 between the second input terminal IN2 and second output terminal OUT2.First feedback static
The feedback of capacitance Cfb1 and second static capacity Cfb is realized respectively with variable static capacity.
On the other hand, it is connected with first switch SW1 between the second input terminal of amplifier FEA and virtual channel DC,
Be connected with second switch SW2 between the both ends of first feedback static capacity Cfb1, the both ends of the second feedback static capacity Cfb2 it
Between be connected with third switch SW3.Also, reference voltage is optionally supplied to the second input terminal IN2 of amplifier FEA
Vref may also include reset (reset) the switch SWr for controlling it.Also, it can apply to amplifier FEA and be used for
The supply voltage VDD of work.
Virtual channel DC is connected with following read line, above-mentioned read line and the multiple pixels for constituting sensor panel 100
A possibility that being in contact in 110 (referring to Fig.1) with test object object is not present or more than one the smallest (ginseng of benchmark pixel 111
According to Fig. 1) it is connected.
Hereinafter, being illustrated to the work of sensitivity improving circuit 311.
Firstly, control reset switch SWr is in the open state, the first input end IN1 and the second input terminal of amplifier FEA
IN2 is reset to reference voltage Vref.Meanwhile second switch SW2 and third switch SW3 are controlled so as to opening state, reset amplification
Feedback static capacity Cfb1, Cfb2 of device FEA.
Later, reset switch SWr, second switch SW2 and third switch SW3 are controlled so as to closed state and first switch
SW1 conversion is in an open state, and the specific list flowed by specific read line RL is inputted to the first input end IN1 of amplifier FEA
The output electric current Id of position pixel 110, the benchmark flowed by virtual channel DC is inputted to the second input terminal IN2 of amplifier FEA
The output electric current Ir of pixel 111.
The output electric current Id of the specific unit pixel 110 inputted to first input end IN1 is converted to first by amplifier FEA
Voltage V1 to export to the first output end OUT1.Also, the benchmark pixel 111 that amplifier FEA will be inputted to the second input terminal IN2
Output electric current Ir be converted to second voltage V2 come to second output terminal OUT2 export.
The electric current Id exported from specific unit pixel 110 can be considered as the case where there is no the noises based on external disturbance etc.
The value that is added with the output electric current In based on noise of the output electric current Ids of pure unit pixel 110.Amplifier FEA is to this defeated
Electric current Id is amplified and is converted to the first voltage value V1 to export out, therefore the first voltage value V1 becomes to based on pure detection pair
As the voltage value Vds of the output electric current Ids amplification conversion of the unit pixel 111 of the contact of object and to the output electric current based on noise
The value (V1=Vds+Vn) that the voltage value Vn of In amplification conversion is added.
Also, since benchmark pixel 111 does not connect with test object object, the output electric current from benchmark pixel 111
Ir can be considered as the electric current In of the noise based on external disturbance etc..Amplifier FEA amplifies simultaneously the electric current In based on noise
Second voltage value V2 is converted to export, therefore second voltage value V2 becomes the amplification conversion to the electric current In based on pure noise
Voltage value Vn (V2=Vn).
The the first output end OUT1 and second output terminal OUT2 of amplifier FEA respectively with a multiplexer 321,322
It is connected.That is, if being set to multiplexing portion 320 there are n according to the read line in the image read-out of an embodiment
The quantity of multiplexer 321,322 be 2n.
Pass through the first output end OUT1 and second output terminal OUT2 of the amplifier FEA that multiplexer 321,322 inputs
Signal, that is, the first voltage value V1 and second voltage value V2 is successively inputted to Analog-digital Converter portion 330 (referring to Fig.1).
Analog-digital Converter portion 330 carries out difference to the first voltage value V1 and second voltage value V2 sequentially input and converts
It is exported for digital value.The first voltage value V1 is the output electric current Ids of the unit pixel 111 of the contact based on pure test object object
Amplify the value that the voltage value Vds of conversion is added with the voltage value Vn of the output electric current In amplification conversion based on noise, second voltage
Value V2 be based on pure noise electric current In amplification conversion voltage value Vn, therefore to the first voltage value V1 and second voltage value V2 into
Row difference, then it is exportable removal the signal based on noise value (V1-V2=Vds+Vn-Vn=Vds).
That is, in image read-out, letter caused by the noise based on external disturbance etc. can be obtained according to an embodiment
The signal for the influence based on pure test object object that number value is removed, it is possible thereby to improve image detection sensitivity.
On the other hand, referring again to Fig. 2, as described above, the electric current Id exported from specific pixel 110 is according to second transistor
The gate source voltage Vgs of T2 and it is different.Fig. 4 shows its relationship.
The grid voltage of second transistor T2 changes according to induction static capacity Cs, incudes static capacity Cs according to sensing
Pad SP and which region of test object object connect and it is different as described above.
Assuming that the case where test object object is fingerprint, as the ridge for contacting fingerprint on sensor mat SP is formed by the second crystal
The gate source voltage Vgs of pipe T2, the gate source voltage Vgs of second transistor T2 is formed by with the paddy for contacting fingerprint on sensor mat SP
In the chart of Fig. 4 the 3. region when, thus caused by unit pixel 110 output electric current Id difference it is also abundant, because
This can obtain fingerprint image based on the output electric current Id.
However, as described above, if being configured with thicker protective layer on finger print detection device, fingerprint and sensor mat SP it
Between the size of induction static capacity Cs become smaller, therefore be formed by second transistor in the case where contacting fingerprint on sensor mat SP
The size (absolute value) of the gate source voltage Vgs of T2 also becomes smaller.
If the size of gate source voltage Vgs is located at due tos because occurrence features are spread in the influence of protective layer or process the problem of etc.
The 6. region, then contact with ridge with sensor mat SP or contact independently with paddy, and the output electric current Id of unit pixel 110 is lower than making an uproar
Sound grade, so that ridge and the paddy of fingerprint cannot be distinguished.Also, even if removal noise, the output electric current Id's of the ridge based on fingerprint
The size of the value of the output electric current Id of value and the paddy based on fingerprint is little, to be unable to ensure high sensitivity.
One embodiment of the invention for solving the above problems, institute in the sensitivity improving circuit 311 illustrated referring to Fig. 3
Including amplifier FEA feedback static capacity Cfb size and to feedback static capacity Cfb1, Cfb2 charging charge time
At least one of may be changed.
It is illustrated referring to Fig. 3, the electric current of amplifier FEA opposite direction first input end IN1 and the second input terminal IN2 input
Id, In amplification conversion are distinguished to export the first voltage value V1 and second voltage value V2, the first voltage value V1 and second voltage value V2
It is represented by following mathematical expression.
V1=(Id-t1)/Cfb1
V2=(In-t2)/Cfb2
T1 and t2 is respectively that the feedback of the first feedback static capacity Cfb1 and second static capacity Cfb2 maintains charged state
Time, that is, second switch SW2 and third switch SW3 remains off the time of state.
In above-mentioned mathematical expression, if changing at least one of t1, t2, Cfb1, Cfb2, exported from amplifier FEA the
The size of one voltage value V1 and second voltage value V2 can also change, and the final output signal of the contact of the ridge based on fingerprint and be based on
Difference between the final output signal of paddy also will increase.Also, amplifier FEA also can control to avoid becoming saturation state.
According to an embodiment, t1, t2, Cfb1, Cfb2 can be in the picture element signal reading parts 300 of designed image reading device
When be determined, can also fingerprint incude work in be determined.
According to an embodiment, when the design of sensitivity improving circuit 311 shown in Fig. 3, obtains and input to amplifier FEA
Electric current IN1, IN2 and amplification conversion output voltage V1, V2 between relationship and according to t1, t2, Cfb1, Cfb2 variation it is defeated
Out after voltage V1, V2 etc., in the case that test object object is fingerprint, reaction based on fingerprint not in contact with when, contact with the ridge of fingerprint
When, output electric current when being contacted with the paddy of fingerprint, thus can determine the degree that can obtain the ridge and paddy that can clearly distinguish fingerprint
Output voltage V1, V2 t1, t2, Cfb1, Cfb2 value.
Also, it according to another embodiment, is also provided in image read-out for adjusting the first feedback static capacity
The size and the individual control unit in each charging time (not shown) of the feedback of Cfb1 and second static capacity Cfb2, this control
Portion processed can generate and use according to the value of the gate source voltage Vgs or output electric current Id for the second transistor T2 for being set to specific pixel 110
In the size and each charging time that can be changed the first feedback static capacity Cfb1 of setting and the second feedback static capacity Cfb2
Control command signal.In the case, the first feedback static capacity Cfb1 and the second feedback static capacity Cfb2 can be implemented as
Variable static capacity.
For example, that the size of electric current Id, Ir that opposite sensitivity improving circuit 311 inputs are incuded as a result, if judgement
A possibility that beyond preset critical current, then to can determine whether to be likely to become saturation state there are amplifier FEA, and will feedback
The value for being dimensioned to be higher by preset size of static capacity Cfb1, Cfb2.Also, it is judged as the work of present amplifier FEA
In the case where making state as saturation state, when incuding work later, being dimensioned to for static capacity Cfb1, Cfb2 can will be fed back
It is higher by the value of preset size.
As another example, the case where deviation of the multiple electric current Id inputted to sensitivity improving circuit 311 is less than preset value
Under, in order to amplify its difference, the time that feedback static capacity Cfb1, Cfb2 of amplifier FEA can be executed to charging work increases.
That is, increased by the time that second switch and third switch SW3 are remained off to state, the gain of Lai Tigao amplifier FEA
Embodiment can also be realized.At this point, reduce feedback static capacity Cfb1, the Cfb2 size of amplifier FEA as another method,
Method to improve gain can also be realized.
The induction of above-mentioned electric current Id, Ir size, the induction of the working condition of amplifier FEA and the deviation sense of multiple electric current Id
It should can be executed by individual control unit is (not shown).This control unit is according to above-mentioned induction as a result, being used to control feedback to generate
The control at least one of the size of static capacity Cfb1, Cfb2 and the charging time for feeding back static capacity Cfb1, Cfb2
Signal.
According to the present embodiment, even if being configured with thicker protective layer on image read-out, the influence of noise can also be made
It minimizes, and test object object can be accurately identified.
Also, according to the present embodiment, in image read-out, even if determining that the transistor of the output signal of pixel does not exist
Work in optimum range, can also be sensitive to ensure to sense by size of devices in control sensitivity improving circuit and working time
Degree.
Above-mentioned explanation of the invention be for illustration, for those skilled in the art,
Do not change technical idea of the invention or must feature in the case where can it is easily deformable for other specific forms be it is aobvious and
It is clear to.
Therefore, the embodiment of the above record is only used for illustration in all cases, is not used to restriction.Example
Such as, each structural element illustrated in singular form can disperse to implement, and equally, the structural element illustrated in a dispersed form can also
Combining form is implemented.
The scope of the present invention should be depending on invention protection scope, from the meaning and range of invention protection scope and equivalent
The derived form for having altered or deforming of concept, which should be interpreted that, to be all belonged to the scope of the present invention.
Claims (9)
1. a kind of image read-out, including multiple pixels to constitute the matrix shape configuration of multiple row and columns, feature exists
In, comprising:
Picture element signal processing circuit amplifies conversion to the first output electric current and the second output electric current to export the first electricity respectively
Pressure value and second voltage value, the first output electric current are exported from the first pixel and by the signal based on test object object and are based on
The signal of noise is added, and the second output electric current is exported from the second pixel and including the signal based on noise；And
Analog-digital Converter portion carries out difference to the first voltage value and second voltage value to digitize.
2. image read-out according to claim 1, which is characterized in that
Second pixel is at least one pixel being configured at outside effective coverage in the multiple pixel.
3. image read-out according to claim 1, which is characterized in that
The picture element signal processing circuit includes quantity signal deteching circuit identical with the quantity of the column.
4. image read-out according to claim 3, which is characterized in that
The signal deteching circuit includes:
Amplifier, first input end are connected with first pixel, the second input terminal selectively with the second pixel phase
Connection；
First feedback static capacity, is connected between the first input end of the amplifier and the first output end；And
Second feedback static capacity, is connected between the second input terminal of the amplifier and second output terminal.
5. image read-out according to claim 4, which is characterized in that
Reference voltage is selectively supplied to the second input terminal of the amplifier.
6. image read-out according to claim 4, which is characterized in that
The first output end and second output terminal of the amplifier are connected with multiplexer respectively.
7. image read-out according to claim 6, which is characterized in that
The Analog-digital Converter portion is believed by the first output end of the amplifier being sequentially output by the multiplexer
Number and second output terminal signal carry out difference and digitized.
8. image read-out according to claim 4, which is characterized in that
It further include control unit, the control unit changes the big of the first feedback static capacity in each signal deteching circuit
At least one of small, size of the second feedback static capacity.
9. image read-out according to claim 4, which is characterized in that
It further include control unit, the control unit changes the first feedback static capacity in each signal deteching circuit by described
In the time that the time of first output electric current charging and the second feedback static capacity export electric current charging by described second extremely
It is one few.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| KR1020170146825A KR101913650B1 (en) | 2017-11-06 | 2017-11-06 | Biometric image read-out apparatus in display area |
| KR10-2017-0146825 | 2017-11-06 |
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| Publication Number | Publication Date |
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| CN109753860A true CN109753860A (en) | 2019-05-14 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201711157658.3A Pending CN109753860A (en) | 2017-11-06 | 2017-11-20 | Biometric image reading device in display area |
| CN201721559895.8U Expired - Fee Related CN207489037U (en) | 2017-11-06 | 2017-11-20 | Biometric image reading device in display area |
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| Application Number | Title | Priority Date | Filing Date |
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| CN201721559895.8U Expired - Fee Related CN207489037U (en) | 2017-11-06 | 2017-11-20 | Biometric image reading device in display area |
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| Country | Link |
|---|---|
| KR (1) | KR101913650B1 (en) |
| CN (2) | CN109753860A (en) |
| WO (1) | WO2019088783A1 (en) |
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| Publication number | Publication date |
|---|---|
| KR101913650B1 (en) | 2018-10-31 |
| CN207489037U (en) | 2018-06-12 |
| WO2019088783A1 (en) | 2019-05-09 |
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Application publication date: 20190514 |