CN101532874B - Optical sensor for display device - Google Patents
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- CN101532874B CN101532874B CN2008100860426A CN200810086042A CN101532874B CN 101532874 B CN101532874 B CN 101532874B CN 2008100860426 A CN2008100860426 A CN 2008100860426A CN 200810086042 A CN200810086042 A CN 200810086042A CN 101532874 B CN101532874 B CN 101532874B
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Abstract
The invention relates to an optical sensor for a display device. The optical sensor comprises an optical receiver, a reset unit and a sampling unit. The optical receiver comprises a first transistor and a first transforming unit which transforms the output of the first transistor into photovoltage; the reset unit responds a reset signal so as to provide an initialized reference voltage and comprises a second transistor and a third transistor which are mutually connected. The control end of the second transistor is connected with the reset signal and the control end of the third transistor is connected with the first transforming unit. The sampling unit responds a sampling signal, outputs photovoltage corresponding to received light quantity, and comprises a fourth transistor which responds the sampling signal and a second transforming unit which transforms the output of the fourth transistor into photovoltage. The optical sensor can obtain a relatively wide output photovoltage change range and effectively reduce circuit elements and layout area so as to save costs. In addition, the optical sensor can prolong service life by effectively preventing threshold voltage deviation.
Description
Technical field
The present invention is about a kind of optical sensor, particularly about a kind of optical sensor that is arranged in the display device with the sensing environmental light brightness.
Background technology
One ambient light sensing element (ambient light sensor) is set on display device, can measurement environment the intensity of illumination adjust the light-source brightness of display device with correspondence, so can meet the requirement that good display effect is provided and reduces power consumption simultaneously.
Fig. 1 is for showing the circuit diagram of a known optical sensor 100, and Fig. 2 is the sequential chart of the signal of the optical sensor 100 of demonstration input Fig. 1.Please also refer to Fig. 1 and Fig. 2, optical sensor 100 comprises a sensing transistor Q1, and selects transistor Q2, an electric current to produce transistor Q3, an output transistor Q4, reaches a capacitor C 1.Optical sensor 100 outputs one sensor current Iout, the value of electric current I out depends on the light quantity that is received.Sensing transistor Q1 is supplied one first voltage VDD and one second voltage VGG, when selecting signal SELECT in high levels, select transistor Q2 conducting so that sensing transistor Q1, capacitor C 1 are electrically connected to the first voltage VDD, sensing transistor Q1 did not produce photocurrent and capacitor C 1 and charged to and have the first voltage VDD this moment, but and when reading signal READ in high levels conducting output transistor Q4 and export the first voltage VDD.On the other hand, when selecting signal SELECT in low level, select transistor Q2 to close so that sensing transistor Q1, capacitor C 1 all disconnect with the first voltage VDD, capacitor C 1 store charge is applied to the photovoltage of electric current generation transistor Q3 with generation at this moment.Therefore, the value of sensor current Iout depends on the difference of photovoltage with respect to the first voltage VDD.Moreover, but when reading signal READ in high levels conducting output transistor Q4, make the photovoltage Vout of transistor Q4 output respective sensor electric current I out size.
The shortcoming of above-mentioned design is that electric current produces transistor Q3 under the situation that is subjected to negative bias for a long time, can produce limit voltage and be offset (threshold voltage shift) phenomenon and cause damage easily; On the other hand, because each the replacement during (reset) circuit operation, node n1 voltage can be set in the first voltage VDD according to above-mentioned design, and so the variation range of reference voltage and both differences of photovoltage can be very little.
Fig. 3 is for showing the circuit diagram of known another optical sensor 200 designs.As shown in Figure 3, optical sensor 200 comprises a sensing circuit 202, a generating circuit from reference voltage 204, reaches a processing unit 206.Sensing circuit 202 comprises a sensing transistor Q1, a reset transistor Q2, a switching transistor Q3, reaches two capacitor C 1, C2.Generating circuit from reference voltage 204 comprises a sensing transistor Q4, a reset transistor Q5, a switching transistor Q6, reaches two capacitor C 3, C4.Sensing transistor Q1 is supplied one first voltage VDD and one second voltage VGG, and capacitor C 1, C2 connect a tertiary voltage VDC.Optical sensor 200 utilizes a gate drivers (figure does not show) to drive, when reset transistor Q2 conducting, circuit is done the action of resetting, and this moment, switching transistor Q3 exported conducting by the first order of gate drivers, made the switching transistor Q3 of optical sensor 200 obtain a reference voltage Δ V1.Thereafter wait sensing transistor Q1 irradiation after a period of time, switching transistor Q3 is by the afterbody of gate drivers output conducting, and this moment, the switching transistor Q3 of optical sensor 200 obtained a photovoltage Δ V2 after changing.When switching signal SWITCH is high levels, can take out reference voltage Δ V1 or change after photovoltage Δ V2.Advantage of this design is the mechanism that circuit is reset, so can make reference voltage and change after the variation range of both differences of photovoltage wider.Yet shortcoming of this design is for needing two groups of circuit, that is utilizes one group of sensing circuit 202 to produce photovoltages and utilize another group generating circuit from reference voltage 204 to produce reference voltages, so will make the parts number of optical sensor 200 too much increase manufacturing cost.
Summary of the invention
The object of the present invention is to provide a kind of optical sensor that is used for display device, it can obtain the sensing scope of a broadness with the less elements number, and can improve the mission life of circuit component.
According to an enforcement kenel of the present invention, a kind of optical sensor that is used for display device comprises an optical receiver, a reset cell and a sampling unit.Optical receiver receives exterior light and produces the photovoltage of a corresponding light quantity that receives, and comprises a first transistor, reaches one first converting unit that the output of the first transistor is converted to photovoltage.Reset cell is responded a reset signal so that an initialized reference voltage to be provided, and comprise a transistor seconds connected to one another and one the 3rd transistor, the control end of transistor seconds connects reset signal and the 3rd transistorized control end connects first converting unit, and first converting unit is discharged to obtain initialized reference voltage via the 3rd transistor when the transistor seconds conducting.Sampling unit is responded the photovoltage of the corresponding light quantity that receives of sampled signal output, and comprises one the 4th transistor of responding this sampled signal, reaches one second converting unit that the 4th transistorized output is converted to photovoltage.
Implement kenel according to of the present invention another, a kind of optical sensor that is used for display device comprises a sensing circuit, a generating circuit from reference voltage and a processing unit.Sensing circuit comprises one first optical receiver, one first reset cell and one first reading unit.First optical receiver receives exterior light and produces the photovoltage of a corresponding light quantity that receives, and first optical receiver comprises a first transistor, reaches one first converting unit that the output of the first transistor is converted to photovoltage.First reset cell is responded first reset signal so that initialized this photovoltage to be provided, reset cell comprises a transistor seconds and one the 3rd transistor that is electrically connected to each other, the control end of transistor seconds connects first reset signal and the 3rd transistorized control end connects first converting unit, and first converting unit is discharged to obtain initialized photovoltage via the 3rd transistor when the transistor seconds conducting.First reading unit is responded first and is read the photovoltage that signal is exported the corresponding light quantity that receives, and first reading unit comprises response first and reads one the 4th transistor of signal, reaches one second converting unit that the 4th transistorized output is converted to photovoltage.Generating circuit from reference voltage comprises one second optical receiver, one second reset cell and one second reading unit.Second optical receiver is shielded from the exterior light irradiation to produce a reference voltage, and second optical receiver comprises one the 5th transistor, reaches one the 3rd converting unit that the 5th transistorized output is converted to reference voltage.Second reset cell is responded one second reset signal so that an initialized reference voltage to be provided, second reset cell comprises one the 6th transistor and one the 7th transistor that is electrically connected to each other, the 6th transistorized control end connects second reset signal and the 7th transistorized control end connects the 3rd converting unit, and the 3rd converting unit is discharged to obtain initialized reference voltage via the 7th transistor when the 6th transistor turns.Second reading unit is responded a second reading number of winning the confidence with output reference voltage, and second reads unit pack contains one the 8th transistor of responding the second reading number of winning the confidence, and the 8th transistorized output is converted to one the 4th converting unit of reference voltage.Processing unit receives photovoltage and the reference voltage output signal with the difference that produces corresponding photovoltage and reference voltage.
Design by each embodiment of the present invention, when optical sensor is reset action at every turn, storage capacitors voltage can drop to equal by auto zero (auto-zero) discharging action of reset circuit or approach the 3rd transistorized limit voltage (reference voltage), progressively rise with illumination more afterwards, but so optical sensor relative reference voltage obtains a bigger output photovoltage variation range.Moreover, take out by same circuit because of exporting photovoltage and reference voltage, can effectively reduce circuit elements number of packages and layout area to save cost.On the other hand, because of the light sensing transistor is subjected to positive bias (positive gate voltage VGH) and negative bias (illumination voltage) effect in turn, so can effectively avoid the limit voltage skew to produce to improve mission life.
Description of drawings
Fig. 1 is for showing the circuit diagram of a known optical sensor, and Fig. 2 is the sequential chart of the signal of the optical sensor of demonstration input Fig. 1;
Fig. 3 is for showing the circuit diagram of known another sensor design;
Fig. 4 is the circuit diagram according to the optical sensor of one embodiment of the invention, and Fig. 5 is the sequential chart of the signal of the optical sensor of input Fig. 4;
Fig. 6 is the synoptic diagram of the potential change of explanation first electric capacity;
Fig. 7 is the processing unit synoptic diagram according to one embodiment of the invention;
Fig. 8 is the circuit diagram according to the optical sensor of another embodiment of the present invention, and Fig. 9 is the sequential chart of the signal of the optical sensor of input Fig. 8;
Figure 10 is the circuit diagram according to the optical sensor of another embodiment of the present invention.
Drawing reference numeral
10,20,30 optical sensors, 12 processing units
14 amplifiers, 16 analog-digital converters
32 sensing circuits, 34 generating circuit from reference voltage
36 processing units, 100,200 optical sensors
202 sensing circuits, 204 generating circuit from reference voltage
206 processing unit BM shading elements
C1-C4 electric capacity n1 node
Q1-Q6 transistor T 1-T8 transistor
Δ V1 reference voltage Δ V2 photovoltage
The VDD first voltage VGG second voltage
VDC tertiary voltage VGH positive gate voltage
VGL negative-gate voltage Vref reference voltage
Vout output photovoltage READ reads signal
RESET reset signal SELECT selects signal
Beginning signal SWITCH switching signal is opened in STV scanning
The SAMPLE sampled signal
Embodiment
Following with reference to relevant drawings, the sensor design according to preferred embodiment of the present invention is described, wherein components identical will be illustrated with identical drawing reference numeral.
Fig. 4 is the circuit diagram according to the optical sensor 10 of one embodiment of the invention, Fig. 5 is the sequential chart of the signal of the optical sensor 10 of input Fig. 4, design according to present embodiment, because of optical sensor 10 is to be arranged in the display device (figure does not show) with the sensing environmental light brightness, so a gate driving IC (gate driver IC) who provides display device to scan voltage for example is provided the voltage source of optical sensor 10.As shown in Figure 4, optical sensor 10 comprises a first transistor T1, a transistor seconds T2, one the 3rd transistor T 3, one the 4th transistor T 4, one the 5th transistor T 5, one first capacitor C 1, one second capacitor C 2 and one the 3rd capacitor C 3.The one scan that connects the grid of the first transistor T1 opens beginning signal STV, its drain electrode connects one first voltage, and its source electrode connects one second voltage and first capacitor C 1, and this first and second voltage for example can be respectively positive gate voltage VGH and the negative-gate voltage VGL of a gate driving IC.The grid of transistor seconds T2 connects a reset signal RESET, and its drain electrode connects the source electrode of the first transistor T1.The drain electrode of the 3rd transistor T 3 connects the source electrode of transistor seconds T2, and its source electrode connects negative-gate voltage VGL, and its grid connects the source electrode and first capacitor C 1 of the first transistor T1.The grid of the 4th transistor T 4 connects a sampled signal SAMPLE, and its drain electrode connects first capacitor C 1, and its source electrode connects second capacitor C 2.The grid of the 5th transistor T 5 connects one and reads signal READ, and its drain electrode connects the source electrode and first capacitor C 1 of the first transistor T1, and its source electrode connects the 3rd capacitor C 3.
The first transistor T1 has a photographic layer (figure does not show), it produces electric charge carrier when receiving the certain environment light quantity, this electric charge carrier moves to produce photocurrent I because of drain electrode and the voltage difference between source electrode of the first transistor T1, and the value of photocurrent I depends on the light quantity that receives.Please also refer to Fig. 4 and Fig. 5, when scanning opens that the beginning, signal STV was high levels, the first transistor T1 conducting, this moment, positive gate voltage VGH saw through the first transistor T1 to the action of charging of first capacitor C 1.Then when reset signal RESET is high levels, transistor seconds T2 conducting, this moment the 3rd transistor T 3 also conducting make the electric weight that is stored in first capacitor C 1 via 3 discharges of the 3rd transistor T, the current potential of first capacitor C 1 like this can drop to and equate with the limit voltage (threshold voltage) of the 3rd transistor T 3 or almost equal.And then when reading signal READ and be high levels, the output of 5 conductings of the 5th transistor T and the 5th transistor T 5 is converted to the potential difference (PD) of the 3rd capacitor C 3, so can take out reference voltage Vref by the 3rd capacitor C 3, this moment, reference voltage Vref was the limit voltage (threshold voltage) of the 3rd transistor T 3.Because the limit voltage of different transistor T 3 may have a little difference, be used as the design of reference voltage Vref in this limit voltage, can obtain to adjust the effect that optimal reference voltage Vref is used for optical sensor 10 at the characteristic of each transistor T 3 with the 3rd transistor T 3.On the other hand, when reset signal RESET is low level, transistor seconds T2 turn-off so the time first capacitor C 1 current potential flow to 1 charging of 1 pair first capacitor C of first capacitor C along with photocurrent I and progressively rise, and this moment, reference voltage Vref all was maintained fixed.Therefore, when sampled signal SAMPLE is high levels, the output of the 4th transistor T 4 conductings this moment and the 4th transistor T 4 is converted to the potential difference (PD) of second capacitor C 2, so can take out the photovoltage Vout after the variation after surround lighting shines by second capacitor C 2, this moment, photovoltage Vout was the current potential after first capacitor C 1 changes via photocurrent I charging.
The potential change of first capacitor C 1 shows as Fig. 6, can know by Fig. 6 and to find out, by transistor seconds T2 and collaborative auto zero (auto-zero) discharging action of the 3rd transistor T 3, the current potential of first capacitor C 1 can drop to the limit voltage that equates or approach the 3rd transistor T 3 by positive gate voltage VGH, and this limit voltage is exportable as a fixing reference voltage Vref.Thereafter the current potential of first capacitor C 1 is along with surround lighting irradiation is progressively risen, take a sample at last and output photovoltage Vout and reference voltage Vref have a potential difference (PD) Δ V.As shown in Figure 7, processing unit 12 receives output photovoltage Vout and the reference voltage Vref output signal with the difference that produces corresponding photovoltage and reference voltage.In detail, processing unit 12 comprises an amplifier 14 and an analog-digital converter (ADC) 16, after the output photovoltage Vout that sampling records and the difference DELTA V of reference voltage Vref amplify via amplifier 14, convert digital briliancy control signal to by analog-digital converter 16 again, adjust backlight illumination according to briliancy control signal value afterwards, so can meet the requirement that good display effect is provided and reduces power consumption simultaneously.
Design by the foregoing description, when optical sensor 10 is reset (reset) action at every turn, storage capacitors voltage can drop to the limit voltage (reference voltage) of the 3rd transistor T 3 by auto zero (auto-zero) discharging action of reset circuit, progressively rise with illumination more afterwards, but so optical sensor 10 relative reference voltages obtain a bigger output photovoltage variation range.Moreover, take out by same circuit because of exporting photovoltage and reference voltage, can effectively reduce circuit elements number of packages and layout area to save cost.On the other hand, light sensing transistor (the first transistor T1) is generally all operated at the negative voltage operation interval, because the current characteristics in this interval is preferable, yet be subjected to for a long time under the situation of negative bias, can produce tangible limit voltage and be offset (threshold voltage shift) phenomenon and cause damage easily.Therefore, the present embodiment design makes the grid bias signal trigger once in frame (frame) cycle, make the first transistor T1 be subjected to positive bias (positive gate voltage VGH) and negative bias (illumination voltage) effect in turn, so can effectively avoid the limit voltage skew to produce.
Fig. 8 is the circuit diagram according to the optical sensor 20 of another embodiment of the present invention, and Fig. 9 is the sequential chart of the signal of the optical sensor 20 of input Fig. 8.Please also refer to Fig. 8 and Fig. 9, connect the grid of the 5th transistor T 5 and the source electrode of the 3rd transistor T 3 simultaneously because of reading signal READ, the 3rd transistor T 3 is turn-offed in present embodiment.
Figure 10 is the circuit diagram according to the optical sensor 30 of another embodiment of the present invention, and the signal timing diagram of the optical sensor 30 of input Figure 10 can be similar with Fig. 9.As shown in figure 10, optical sensor 30 comprises a sensing circuit 32, a generating circuit from reference voltage 34 and a processing unit 36.Sensing circuit 32 comprises a first transistor T1, a transistor seconds T2, one the 3rd transistor T 3, one the 4th transistor T 4, one first capacitor C 1 and one second capacitor C 2.The input end of the first transistor T1 connects positive gate voltage VGH, and its control end connects one scan and opens beginning signal STV, and its output terminal connects first capacitor C 1.The input end of transistor seconds T2 connects the output terminal of the first transistor T1, and the control end of transistor seconds T2 connects a reset signal RESET.The input end of the 3rd transistor T 3 connects the output terminal of transistor seconds T2, and the control end of the 3rd transistor T 3 connects first capacitor C 1, and the 3rd transistorized output terminal connects negative-gate voltage VGL.The input end of the 4th transistor T 4 connects first capacitor C 1, and signal READ is read in its control end connection, and its output terminal connects second capacitor C 2.Generating circuit from reference voltage 34 comprises one the 5th transistor T 5, one the 6th transistor T 6, one the 7th transistor T 7, one the 8th transistor T 8, one the 3rd capacitor C 3 and one the 4th capacitor C 4.The circuit connecting relation of generating circuit from reference voltage 34 and sensing circuit 32 are similar, so no longer be repeated in this description in this, both main difference are that generating circuit from reference voltage 34 is provided with a shading element (light blocking member) BM in addition and makes it avoid suffering exterior light to shine in order to shield the 5th transistor T 5.Otherwise the first transistor T1 of sensing circuit 32 accepts the exterior light irradiation and produces the photovoltage of a corresponding light quantity that receives.Therefore, exportable corresponding the photovoltage Vout that receives light quantity and change of sensing circuit 32, the fixing reference voltage Vref of 34 of generating circuit from reference voltage output, and processing unit 36 receives photovoltage Vout and reference voltage Vref to produce an output signal of corresponding both differences.Processing unit 36 can for example shown in Figure 7ly comprise an amplifier 14 and an analog-digital converter (ADC) 16.In present embodiment, the transistor seconds T2 of sensing circuit 32 and the 3rd transistor T 3 be same to be responded reset signal RESET and carries out aforesaid current potential auto zero (auto-zero) discharge operation so that an initialized photovoltage to be provided, and the 6th transistor T 6 of generating circuit from reference voltage 34 and the 7th transistor T 7 same reset signal RESET that respond carry out current potential auto zero discharge operation so that an initialized reference voltage to be provided.
The above only is an illustrative, but not is restricted person.Anyly be familiar with the modification that this operator all can carry out equivalence according to the embodiment of the invention described above, and do not break away from its spirit and category.Event is any not to break away from spirit of the present invention and category, and to its equivalent modifications of carrying out or change, all should be contained in the preceding attached claim.
Claims (15)
1. an optical sensor that is used for display device is characterized in that, this optical sensor comprises:
One optical receiver, the photovoltage that it receives exterior light and produces a corresponding light quantity that receives, this optical receiver comprises the first transistor with photographic layer and one first converting unit that the output of this first transistor is converted to described photovoltage;
One reset cell, it responds a reset signal so that an initialized reference voltage to be provided, this reset cell comprises a transistor seconds connected to one another and one the 3rd transistor, the control end of this transistor seconds connects described reset signal and the 3rd transistorized control end connects described first converting unit, and when described transistor seconds conducting described first converting unit via the discharge of the 3rd transistor to obtain this initialized reference voltage; And
One sampling unit, it responds this photovoltage of the corresponding light quantity that receives of sampled signal output, and this sampling unit comprises one the 4th transistor of responding this sampled signal and the 4th transistorized output is converted to one second converting unit of described photovoltage,
The input end of wherein said the first transistor connects a positive gate voltage, and the control end of described the first transistor connects one scan and opens the beginning signal, and the output terminal of described the first transistor connects described first converting unit; The input end of described transistor seconds connects the output terminal of described the first transistor, and the described the 3rd transistorized input end connects the output terminal of described transistor seconds; The described the 4th transistorized input end connects described first converting unit, and the described the 4th transistorized control end connects described sampled signal, and the described the 4th transistorized output terminal connects described second converting unit.
2. optical sensor as claimed in claim 1 is characterized in that, described first and described second converting unit be respectively a capacitor.
3. optical sensor as claimed in claim 1 is characterized in that, the described the 3rd transistorized output terminal connects a negative-gate voltage.
4. optical sensor as claimed in claim 1 is characterized in that, described reference voltage essence is the described the 3rd transistorized limit voltage.
5. optical sensor as claimed in claim 1, it is characterized in that, this optical sensor more comprises a reference voltage output unit, this reference voltage output unit is responded one and is read signal exporting this reference voltage, and comprises and respond this one the 3rd converting unit that reads one the 5th transistor of signal and the 5th transistorized output is converted to this reference voltage.
6. optical sensor as claimed in claim 5 is characterized in that, described the 3rd converting unit is a capacitor.
7. optical sensor as claimed in claim 5, it is characterized in that, the described the 5th transistorized input end connects the output terminal of described first converting unit and described the first transistor, the described the 5th transistorized control end connects the described signal that reads, and the described the 5th transistorized output terminal connects described the 3rd converting unit.
8. optical sensor as claimed in claim 5 is characterized in that, the described signal that reads connects the described the 3rd transistorized output terminal.
9. optical sensor as claimed in claim 1, it is characterized in that, described optical sensor more comprises a processing unit, and described processing unit receives described photovoltage and the described reference voltage output signal with the difference that produces corresponding described photovoltage and described reference voltage.
10. an optical sensor that is used for display device is characterized in that, this optical sensor comprises:
One sensing circuit, this sensing circuit comprises:
One first optical receiver, the photovoltage that it receives exterior light and produces a corresponding light quantity that receives, this first optical receiver comprises the first transistor with photographic layer and one first converting unit that the output of this first transistor is converted to described photovoltage;
One first reset cell, it responds one first reset signal so that an initialized described photovoltage to be provided, this reset cell comprises a transistor seconds and one the 3rd transistor that is electrically connected to each other, the control end of this transistor seconds connects described first reset signal and the described the 3rd transistorized control end connects described first converting unit, and when described transistor seconds conducting described first converting unit via described the 3rd transistor discharge to obtain described initialized photovoltage; And
One first reading unit, it responds the one first described photovoltage that reads the corresponding light quantity that receives of signal output, and this first reading unit comprises this first one the 4th transistor that reads signal of response, reaches one second converting unit that the described the 4th transistorized output is converted to described photovoltage;
One generating circuit from reference voltage, this circuit comprises:
One second optical receiver, it is shielded from the exterior light irradiation to produce a reference voltage, and this second optical receiver comprises one the 5th transistor and the 5th transistorized output is converted to one the 3rd converting unit of described reference voltage;
One second reset cell, it responds one second reset signal so that an initialized described reference voltage to be provided, this second reset cell comprises one the 6th transistor and one the 7th transistor that is electrically connected to each other, the 6th transistorized control end connects this second reset signal and the 7th transistorized control end connects described the 3rd converting unit, and when described the 6th transistor turns described the 3rd converting unit via the discharge of the 7th transistor to obtain described initialized reference voltage; And
One second reading unit, it responds a second reading number of winning the confidence exporting described reference voltage, and this second reads unit pack and contain one the 8th transistor of responding this second reading number of winning the confidence and one the 4th converting unit that the 8th transistorized output is converted to described reference voltage; And
One processing unit receives described photovoltage and described reference voltage producing should photovoltage and an output signal of the difference of this reference voltage,
The input end of wherein said the first transistor connects a positive gate voltage, and the control end of this first transistor connects one scan and opens the beginning signal, and the output terminal of this first transistor connects described first converting unit; The input end of described transistor seconds connects the output terminal of this first transistor, and the described the 3rd transistorized input end connects the output terminal of this transistor seconds; The described the 4th transistorized input end connects described first converting unit, and the described the 4th transistorized control end connects the described signal that reads, and the described the 4th transistorized output terminal connects described second converting unit.
11. optical sensor as claimed in claim 10 is characterized in that, described generating circuit from reference voltage more comprises a shading element makes it avoid suffering exterior light to shine to shield described the 5th transistor.
12. optical sensor as claimed in claim 10 is characterized in that, the described first, second, third and the 4th converting unit is respectively a capacitor.
13. optical sensor as claimed in claim 10 is characterized in that, the 3rd transistorized output terminal connects a negative-gate voltage.
14. optical sensor as claimed in claim 10, it is characterized in that, the described the 5th transistorized input end connects a positive gate voltage, and the described the 5th transistorized control end connects one scan and opens the beginning signal, and the described the 5th transistorized output terminal connects described the 3rd converting unit; The described the 6th transistorized input end connects the described the 5th transistorized output terminal, and the described the 7th transistorized input end connects the described the 6th transistorized output terminal, and the described the 7th transistorized output terminal connects a negative-gate voltage; The described the 8th transistorized input end connects described the 3rd converting unit, and the described the 8th transistorized control end connects the described signal that reads, and the described the 8th transistorized output terminal connects described the 4th converting unit.
15. optical sensor as claimed in claim 10 is characterized in that, described processing unit comprises the amplifier of the described voltage difference of an amplification and described voltage difference is converted to an analog-digital converter of digital briliancy control signal.
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| CN101532874B true CN101532874B (en) | 2011-04-13 |
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| CN107093417B (en) | 2017-07-03 | 2020-06-16 | 京东方科技集团股份有限公司 | Photosensitive circuit, driving method thereof and electronic device |
| CN108519151B (en) * | 2018-03-23 | 2020-05-05 | 京东方科技集团股份有限公司 | Photodetection circuit, photodetection method, and photodetection device |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1734241A (en) * | 2004-07-12 | 2006-02-15 | 三洋电机株式会社 | Circuit detecting ambient light |
| EP1887626A1 (en) * | 2006-08-09 | 2008-02-13 | Tohoku University | Optical sensor comprising overflow gate and storage capacitor |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1734241A (en) * | 2004-07-12 | 2006-02-15 | 三洋电机株式会社 | Circuit detecting ambient light |
| EP1887626A1 (en) * | 2006-08-09 | 2008-02-13 | Tohoku University | Optical sensor comprising overflow gate and storage capacitor |
Non-Patent Citations (2)
| Title |
|---|
| JP特开2005-268937A 2005.09.29 |
| JP特开2007-28107A 2007.02.01 |
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