CN109753861A - Biometric image reading device in display area - Google Patents
Biometric image reading device in display area Download PDFInfo
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- CN109753861A CN109753861A CN201711159902.XA CN201711159902A CN109753861A CN 109753861 A CN109753861 A CN 109753861A CN 201711159902 A CN201711159902 A CN 201711159902A CN 109753861 A CN109753861 A CN 109753861A
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- 239000011159 matrix material Substances 0.000 claims abstract description 4
- 230000003068 static effect Effects 0.000 claims description 48
- 238000012360 testing method Methods 0.000 claims description 18
- 238000006243 chemical reaction Methods 0.000 claims description 17
- 238000012545 processing Methods 0.000 claims description 12
- 230000035945 sensitivity Effects 0.000 description 19
- 230000006698 induction Effects 0.000 description 15
- 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 6
- 238000000034 method Methods 0.000 description 5
- 239000011787 zinc oxide Substances 0.000 description 5
- 238000010586 diagram Methods 0.000 description 3
- 230000005611 electricity Effects 0.000 description 3
- 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
- 238000004088 simulation Methods 0.000 description 2
- 230000033228 biological regulation Effects 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 230000006866 deterioration Effects 0.000 description 1
- 239000006185 dispersion Substances 0.000 description 1
- 238000001914 filtration Methods 0.000 description 1
- RHZWSUVWRRXEJF-UHFFFAOYSA-N indium tin Chemical compound [In].[Sn] RHZWSUVWRRXEJF-UHFFFAOYSA-N 0.000 description 1
- AMGQUBHHOARCQH-UHFFFAOYSA-N indium;oxotin Chemical compound [In].[Sn]=O AMGQUBHHOARCQH-UHFFFAOYSA-N 0.000 description 1
- 238000009434 installation Methods 0.000 description 1
- 230000036961 partial effect Effects 0.000 description 1
- 239000004065 semiconductor Substances 0.000 description 1
- 230000006641 stabilisation Effects 0.000 description 1
- 230000036962 time dependent Effects 0.000 description 1
- 238000012795 verification Methods 0.000 description 1
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
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- 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
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- Engineering & Computer Science (AREA)
- Human Computer Interaction (AREA)
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
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- Theoretical Computer Science (AREA)
- Image Input (AREA)
Abstract
The present invention provides the biometric image reading device in a kind of display area, comprising: multiple pixels, to constitute the matrix shape configuration of multiple row and columns；And Analog-digital Converter portion, the multiple analog signals exported from above-mentioned multiple pixels are converted into digital signal, above-mentioned Analog-digital Converter portion includes: reference voltage output section, at least one of size and deviation based on the multiple analog signals inputted export the first reference voltage and the second reference voltage；Analog-digital converter will be used as working range, multiple above-mentioned analog signals be converted to the digital signal of n-bit to export between above-mentioned first reference voltage and the second reference voltage.
Description
Technical field
The present invention relates to the image read-outs in display area, are related in more detail, even if from display area is installed on
In image read-out output signal between deviation it is small, may also indicate that adequately parsing power, keep the influence of noise minimum
Change and improve the image read-out 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 the biology in display area is special
Levy image read-out comprising can be improved the deviation between the signal that each pixel of image read-out exports is small
Parse the analog-to-digital conversion circuit of power or resolution ratio.
Another object of the present invention is to provide make the image reading dress that the influence of noise minimizes and sensitivity improves
It sets.
One embodiment of the invention for reaching above-mentioned purpose provides a kind of image read-out, comprising: multiple pixels,
To constitute the matrix shape configuration of multiple row and columns；And Analog-digital Converter portion, it is multiple by being exported from above-mentioned multiple pixels
Analog signal is converted to digital signal, wherein above-mentioned Analog-digital Converter portion includes: reference voltage output section, based on being inputted
Multiple analog signals size and at least one of deviation, export the first reference voltage and the second reference voltage；Simulate number
Word converter will be used as working range, by multiple above-mentioned analog signals between above-mentioned first reference voltage and the second reference voltage
The digital signal of n-bit is converted to export.
Said reference voltage output portion can be made of R character string portion, and R character string portion includes: multiple resistance, to be serially connected
Mode be connected between first voltage and second voltage；And switch portion, by above-mentioned multiple resistance multiple sections interconnected
The voltage of mutually different node in point is exported respectively as above-mentioned first reference voltage and the second reference voltage.
Said reference voltage output portion can include: the first reference voltage output section, including first resistor and to above-mentioned
One resistance supplies the first variable current source of electric current, above-mentioned to export based on above-mentioned first resistor and above-mentioned first variable current source
First reference voltage；And the second reference voltage output section, including second resistance and to above-mentioned second resistance supply electric current
Second variable current source exports above-mentioned second reference voltage based on above-mentioned second resistance and above-mentioned second variable current source.
Above-mentioned first reference voltage can be the maximum value or bigger than maximum value in the size of multiple above-mentioned analog signals
The value of prescribed level, above-mentioned second reference voltage can be for the minimum values in the size of multiple above-mentioned analog signals or than minimum
It is worth the value of small prescribed level.
Above-mentioned image read-out may also include control unit, and above-mentioned control unit is generated for determining above-mentioned first reference voltage
With the control signal of the second reference voltage.
Above-mentioned image read-out may also include picture element signal processing circuit, to the first output electric current and the second output electric current
Amplify conversion respectively to export the first voltage value and second voltage value, above-mentioned first output electric current is from above-mentioned multiple pixels
The first pixel export and be added by the signal based on test object object with the signal based on noise, it is above-mentioned second output electricity
Stream exports from the second pixel and including the signal based on noise, and above-mentioned Analog-digital Converter portion is to above-mentioned the first voltage value and second
Voltage value carries out difference to be digitized.
Above-mentioned picture element signal processing circuit includes quantity signal deteching circuit identical with the quantity of above-mentioned column, above-mentioned signal
Detection circuit includes: amplifier, and first input end is connected with above-mentioned first pixel, and the second input terminal is selectively with above-mentioned
Two pixels are connected；First feedback static capacity, is connected between the first input end of above-mentioned amplifier and the first output end；With
And second feedback static capacity, be connected between the second input terminal of above-mentioned amplifier and second output terminal.
Above-mentioned image read-out may also include control unit, and above-mentioned control unit can be changed upper in each signal deteching circuit
State at least one of size, the size of the second feedback static capacity of the first feedback static capacity.
Above-mentioned image read-out may also include control unit, and above-mentioned control unit changes above-mentioned in each signal deteching circuit
First feedback static capacity is defeated by above-mentioned second by the time of above-mentioned first output electric current charging and the second feedback static capacity
At least one of the time of electric current charging out.
According to an embodiment, in image read-out, even if small from the deviation between the signal that each pixel exports,
The reference voltage of the adjustable working range as analog-digital converter, to improve for more between above-mentioned small deviation
The parsing power of a analog signal, is achieved in the detection of high-resolution image.
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 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.
Fig. 4 is the attached drawing for showing the structure in Analog-digital Converter portion of one embodiment of the invention.
Fig. 5 is the attached drawing for showing the structure of reference voltage output section of one embodiment of the invention.
Fig. 6 is the attached drawing for showing the structure of reference voltage output section of another embodiment of the present invention.
Fig. 7 be show the sensitivity improving circuit of the output signal processing circuit of one embodiment of the invention structure it is attached
Figure.
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.
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 circuit diagram 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.
The output electric current Id exported from second transistor T2 is converted to voltage value in signal-obtaining portion 300 (referring to Fig.1)
Afterwards, by digitizing and exporting.
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.
Electric current Id is exported according to the inherent characteristic of second transistor T2, i.e., according to current-voltage (I- from pixel 110
V) characteristic and it is different.According to the I-E characteristic, the variation of the gate source voltage of specific sections causes big output electric current Id big
Small variation.
Fig. 3 is the curve for showing the I-E characteristic of common transistor.
Referring to Fig. 2 and Fig. 3, output electric current Id is different according to the gate source voltage Vgs of second transistor T2.In other words,
Export electric current Id size it is different according to the current potential V1 of first node N1, as described above, the current potential V1 of first node N1 according to
Incude the size of static capacity Cs and different.Therefore, output electric current Id for second transistor T2 gate source voltage Vgs sharply
The section (2. or 3.) of variation, even if there is small variation in the current potential V1 of first node N1, can also by output electric current Id with
Its variation of high sensitivity detection.
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
(2. or 3.) source voltage Vgs is in optimum range, can just become larger for the variation of the output electric current Id of fine variation, however
According to the influence of protective layer, the gate source voltage Vgs of second transistor T2 be likely to be present in the optimum range it is outer (for example, 5. or
⑥).In the case, become smaller for the variable quantity of the output electric current Id of the gate source voltage Vgs variation of second transistor T2, cause
It is difficult to ensure the sensitivity of 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 Vgs of second transistor T2 may exceed optimum range in partial pixel, the output electric current Id's in each pixel
In the case that difference is little, cause fingerprint incude sensitivity decline the problem of.
Also, the size for exporting electric current Id is significantly high unlike the noise grade based on external disturbance etc., then is more difficult to lead to
Cross ridge and paddy that this output electric current Id distinguishes fingerprint.
The embodiment of the present invention in order to solve this problem, it is proposed that signal-obtaining portion 300 picture element signal processing circuit and mould
The new structure of quasi- digital converter portion.
Fig. 4 is the attached drawing for showing the structure in Analog-digital Converter portion of one embodiment of the invention.
It include reference voltage output section 331 and simulation number according to the Analog-digital Converter portion 330 of an embodiment referring to Fig. 4
Word converter 332 (ADC, Analog Digital Converter).
Reference voltage output section 331 is exportable for making analog-digital converter 332 execute the first benchmark of signal conversion
Voltage Vref_H and the second reference voltage Vref_L.Analog-digital converter 332 can be by the first reference voltage Vref_H and second
Analog signal output between reference voltage Vref_L is the digital signal of n-bit.That is, the first reference voltage Vref_H can be
Voltage corresponding with the exportable maximum value of analog-digital converter 332, the second reference voltage Vref_L can be and simulation
The corresponding voltage of the exportable minimum value of digital quantizer 332.In other words, the first reference voltage Vref_H and the second benchmark
Voltage Vref_L becomes the maximum value and minimum value of the receivable analog signal of analog-digital converter 332, Analog-digital Converter
The working range of device 332 can be between the first reference voltage Vref_H and the second reference voltage Vref_L.
This first reference voltage Vref_H and the second reference voltage Vref_L can be according to Analog-digital Converter portion 330
Input multiple signals deviation and export different values.
Specifically, the output signal inputted to Analog-digital Converter portion 330 is the output electric current conversion from multiple pixels
Multiple voltage signals, for example, the maximum value of the receivable analog signal of analog-digital converter 332 is 5V and minimum value is 0V
When, if maximum voltage is about 3V in the practical multiple voltage signals inputted to Analog-digital Converter portion 330 and minimum voltage is about
2.5V, even if then digitizing to it, the deviation also between signal is small and is difficult to realize accurate image to test object object
It reads.
In these cases, the first reference voltage Vref_H is arranged according to the reference voltage output section 331 of an embodiment
For 3V or than the voltage of 3V high specified value, and set the second reference voltage Vref_L to the electricity of 2.5V or specified value lower than 2.5V
Pressure, to make analog-digital converter 332 can be by the mould between the first reference voltage Vref_H and the second reference voltage Vref_L
Quasi- signal output is the digital signal of n-bit.
That is, improving digitlization in its deviation even if the deviation between the signal inputted to Analog-digital Converter portion 330 is small
When parsing power or resolution ratio, may finally increase by the deviation between digitized signal, image reading thus can be improved
Accuracy.
Fig. 5 is the attached drawing for showing the structure of reference voltage output section 331 of one embodiment of the invention.
As shown in figure 5, can be by R character string portion 331a and switch portion according to the reference voltage output section 331 of an embodiment
331b is realized.
R character string portion 331a includes the multiple resistance being connected between first voltage V- and second voltage V+ in a series arrangement
R1 to Ri.
Switch portion 331b include be connected with above-mentioned multiple resistance R1 to Ri multiple node N1 to Ni mutually accessed it is more
A switch.
Switch portion 331b works according to from externally input control signal CON, passes through multiple switch existing inside
Work exports the mutually different voltage between first voltage V- and second voltage V+ respectively as the first reference voltage Vref_
H and the second reference voltage Vref_L.
For example, switch portion 331b can save the voltage of Ni_2 node and N1 according to from external control signal CON
The voltage of point is exported respectively as the first reference voltage Vref_H and the second reference voltage Vref_L.
In order to switch portion 331b work and to supply the control unit (not shown) of control signal CON may include real according to one
The image read-out of example is applied, this control unit can be multiple based on inputting to present day analog digital converter portion 330 (referring to Fig. 4)
At least one of deviation between the size of signal and multiple signals supplies control signal to switch portion 331b, with can be defeated
First reference voltage Vref_H appropriate and the second reference voltage Vref_L out.According to another embodiment, control unit can be also based on
From the size of the output electric current of multiple pixels 110 (referring to Fig.1) output and its between at least one of deviation, generate control
Signal.Also, according to another embodiment, control unit can also be based on the multiple output signals exported from final image read-out
Size and its between at least one of deviation, generate above-mentioned control signal.
Fig. 6 is the attached drawing for showing the structure of reference voltage output section 331 of another embodiment of the present invention.
Referring to Fig. 6, reference voltage output section 331 according to another embodiment may include the first reference voltage output section 331c
And the second reference voltage output section 331d.
First reference voltage output section 331c can include: the first variable current source I_H；And first resistor R_H, one end with
Assigned voltage (for example, supply voltage VDD) is connected, and the first variable current source I_H is another between one end and assigned voltage
End is connected with ground potential.
Also, the second reference voltage output section 331d can include: the second variable current source I_L；And second resistance R_L,
One end is connected with assigned voltage (for example, supply voltage VDD), the second variable current source I_L be located at one end and assigned voltage it
Between, the other end is connected with ground potential.
The first of the first reference voltage output section 331c according to the size of the electric current supplied by the first variable current source I_H
One end voltage of resistance R_H is different, using this principle, can export the first reference voltage by one end of first resistor R_H
Vref_H.Identical principle can also be used in second reference voltage output section 331d, exports second by one end of second resistance R_H
Reference voltage Vref_L.
First reference voltage output section 331c and the second reference voltage output section 331d can receive can by first for determination
The control signal CON of the size of the electric current of time-dependent current source I_H and the second variable current source I_L supply.Output control signal CON's
Control unit (not shown) can size based on from multiple signals to present day analog digital converter portion 330 (referring to Fig. 4) input and more
At least one of deviation between a signal, from the size of the output electric current of multiple pixels 110 (referring to Fig.1) output and its it
Between at least one of deviation or from the size and deviation for multiple output signals that final image read-out exports
At least one, export above-mentioned control signal CON.
Fig. 7 is sensitivity improving circuit included in the picture element signal processing circuit for show one embodiment of the invention
The circuit diagram of structure.
Sensitivity improving circuit 311 shown in Fig. 7 is connected with a read line RL of image read-out, this sensitivity
Improve circuit 311 and is set to each read line in picture element signal processing circuit 310.That is, being read according to the image of an embodiment
When the read line in device being taken to be provided with n, sensitivity improving circuit 311 is also equipped with 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.Virtual channel DC is connected with following read line, above-mentioned reading
A possibility that being in contact in line and the multiple pixels 110 (referring to Fig.1) for constituting sensor panel 100 with test object object is not present
Or more than one the smallest benchmark pixel 111 (referring to Fig.1) is connected.
Said reference pixel 111 can be the region not connected with test object in sensor panel 100, such as can be
It is configured at more than one pixel of the outside of the effective coverage (active area) of sensor panel 100.
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.
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 the present 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.
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.
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 of the of Fig. 3, then can not be with the highly sensitive ridge for distinguishing fingerprint and paddy.Also, even if removal noise, the ridge based on fingerprint
Output electric current Id value and paddy based on fingerprint output electric current Id value size it is little, to be unable to ensure highly sensitive
Degree.
One embodiment of the invention for solving the above problems, institute in the sensitivity improving circuit 311 illustrated referring to Fig. 7
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. 7, 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. 7, 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 characterized by comprising
Multiple pixels, to constitute the matrix shape configuration of multiple row and columns；And
The multiple analog signals exported from above-mentioned multiple pixels are converted to digital signal by Analog-digital Converter portion,
Wherein, above-mentioned Analog-digital Converter portion includes:
Reference voltage output section, at least one of size and deviation based on the multiple analog signals inputted, output first
Reference voltage and the second reference voltage；
Analog-digital converter will be used as working range, on multiple between above-mentioned first reference voltage and the second reference voltage
It states analog signal and is converted to the digital signal of n-bit to export.
2. image read-out according to claim 1, which is characterized in that said reference voltage output portion is by R character string
Portion is constituted, and R character string portion includes:
Multiple resistance, are connected between first voltage and second voltage in a manner of being serially connected；And
Switch portion, using the voltage of the mutually different node in above-mentioned multiple resistance multiple nodes interconnected as upper
The first reference voltage and the second reference voltage are stated to export.
3. image read-out according to claim 1, which is characterized in that said reference voltage output portion includes:
First reference voltage output section supplies the first variable current of electric current including first resistor and to above-mentioned first resistor
Source exports above-mentioned first reference voltage based on above-mentioned first resistor and above-mentioned first variable current source；And
Second reference voltage output section supplies the second variable current of electric current including second resistance and to above-mentioned second resistance
Source exports above-mentioned second reference voltage based on above-mentioned second resistance and above-mentioned second variable current source.
4. image read-out according to claim 1, which is characterized in that
Above-mentioned first reference voltage is the maximum value or prescribed level bigger than maximum value in the size of multiple above-mentioned analog signals
Value,
Above-mentioned second reference voltage is the minimum value or prescribed level smaller than minimum value in the size of multiple above-mentioned analog signals
Value.
5. image read-out according to claim 1, which is characterized in that further include control unit, above-mentioned control unit generates
For determining the control signal of above-mentioned first reference voltage and the second reference voltage.
6. image read-out according to claim 1, which is characterized in that
Further 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 from the first pixel output in above-mentioned multiple pixels and by being based on
The signal of test object object is added with the signal based on noise, it is above-mentioned second output electric current exported from the second pixel and including
Signal based on noise,
Above-mentioned Analog-digital Converter portion carries out difference to above-mentioned the first voltage value and second voltage value to digitize.
7. image read-out according to claim 6, which is characterized in that
Above-mentioned picture element signal processing circuit includes quantity signal deteching circuit identical with the quantity of above-mentioned column,
Above-mentioned signal deteching circuit includes:
Amplifier, first input end are connected with above-mentioned first pixel, the second input terminal selectively with above-mentioned second pixel phase
Connection；
First feedback static capacity, is connected between the first input end of above-mentioned amplifier and the first output end；And
Second feedback static capacity, is connected between the second input terminal of above-mentioned amplifier and second output terminal.
8. image read-out according to claim 7, which is characterized in that further include control unit, above-mentioned control unit changes
In the size of above-mentioned first feedback static capacity in each signal deteching circuit, the size of the second feedback static capacity at least
One.
9. image read-out according to claim 7, which is characterized in that further include control unit, above-mentioned control unit changes
The time and second that above-mentioned first feedback static capacity in each signal deteching circuit is charged by above-mentioned first output electric current
Static capacity is fed back by least one of the time of above-mentioned second output electric current charging.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| KR10-2017-0146826 | 2017-11-06 | ||
| KR1020170146826A KR101922516B1 (en) | 2017-11-06 | 2017-11-06 | Biometric image read-out apparatus comprising the same in display area |
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| CN109753861A true CN109753861A (en) | 2019-05-14 |
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| CN201711159902.XA Pending CN109753861A (en) | 2017-11-06 | 2017-11-20 | Biometric image reading device in display area |
| CN201721559928.9U Expired - Fee Related CN207571758U (en) | 2017-11-06 | 2017-11-20 | Biometric image reading device in display area |
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| CN201721559928.9U Expired - Fee Related CN207571758U (en) | 2017-11-06 | 2017-11-20 | Biometric image reading device in display area |
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| Country | Link |
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| KR (1) | KR101922516B1 (en) |
| CN (2) | CN109753861A (en) |
| WO (1) | WO2019088784A1 (en) |
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- 2017-11-06 KR KR1020170146826A patent/KR101922516B1/en active IP Right Grant
- 2017-11-20 CN CN201711159902.XA patent/CN109753861A/en active Pending
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| Publication number | Publication date |
|---|---|
| KR101922516B1 (en) | 2018-11-27 |
| CN207571758U (en) | 2018-07-03 |
| WO2019088784A1 (en) | 2019-05-09 |
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