阅读说明：本技术 改善像素感测效率的电路 (Improve the circuit of pixels sense efficiency ) 是由 唐宽 邱奕诚 郭家祺 邱瑞德 刘汉麒 于 2019-05-20 设计创作，主要内容包括：一种改善像素感测效率的电路,其利用电容的感应效果来复制多余电子造成的电压差异,并在读出像素资料的时候使用电路将所述电压差异扣除,以改善感测效率。(A kind of circuit improving pixels sense efficiency, voltage differences caused by excess electron are replicated using the inductive effects of capacitor, and are deducted the voltage differences using circuit when reading pixel information, to improve sensing efficiency.)

1. a kind of sensing circuit, which includes:

Optical diode；

First capacitor, the first capacitor connect the first floating diffusion nodes, produce for storing the optical diode during temporary Raw photosensitive signal；

Second capacitor, second floating diffusion nodes of the second capacitance connection, in the temporary period storage resetting signal；With And

Reading circuit, the reading circuit are used for

Signal is reset after keeping in after the temporary period from second floating diffusion nodes reading and is floated from described first Dynamic diffusion node reads temporary rear photosensitive signal, and

The signal of resetting signal and the temporary rear photosensitive signal is poor after calculating described keep in, and is produced with eliminating the temporary period Raw noise voltage.

2. sensing circuit according to claim 1, also includes:

First electric charge transfer controls transistor, is connected between the optical diode and first floating diffusion nodes；And

Second electric charge transfer controls transistor, be connected to first floating diffusion nodes and second floating diffusion nodes it Between.

3. sensing circuit according to claim 1, wherein the reading circuit first reads the resetting signal after keeping in again Read the temporary rear photosensitive signal.

4. a kind of sensing circuit, which includes:

Optical diode；

First voltage source, the first voltage source have the first reset voltage；

The second voltage source, the second voltage source have the second reset voltage；

Capacitor, the capacitor have first electrode and second electrode, and the first electrode is coupled to floating diffusion nodes and temporary The photoreceptor voltage generated when period starts with the optical diode, the second electrode have when the temporary period starts Second reset voltage, wherein the first electrode and the second electrode have same object characteristic；

Rear end reset transistor, the rear end reset transistor are connected to second electricity of the second voltage source and the capacitor Between pole；And

Reading circuit, the reading circuit are used for

Institute is read after the temporary period and when the first electrode of the capacitor is connected to the first voltage source The first read-out voltage of the second electrode of capacitor is stated,

After first read-out voltage reading and when the second electrode of the capacitor is connected to the second voltage source The second read-out voltage of the second electrode of the capacitor is read, and

The voltage difference of first read-out voltage Yu second read-out voltage is calculated, to eliminate caused by the temporary period Noise voltage.

5. sensing circuit according to claim 4, also comprising remove transistor be connected to the first voltage source with it is described Between the first electrode of capacitor.

6. sensing circuit according to claim 5, also includes:

Tertiary voltage source；

Electric charge transfer controls transistor, is connected between the first electrode of the capacitor and the optical diode；And

Reset transistor is connected between the tertiary voltage source and the optical diode.

7. sensing circuit according to claim 4, wherein the first electrode when the capacitor is connected to described first When voltage source, the second electrode suspension joint of the capacitor.

8. a kind of sensing circuit, which includes:

Optical diode；

First voltage source, the first voltage source have the first reset voltage；

The second voltage source, the second voltage source have the second reset voltage；

Capacitor, the capacitor have first electrode and second electrode, and the first electrode coupled floating diffusion nodes and in the temporary phase Between the photoreceptor voltage that is generated during exposure with optical diode when starting, the second electrode opens in the temporary period There is second reset voltage, wherein the first electrode and the second electrode have same object characteristic when the beginning；

Transistor, the support transistor is supported to be connected between the second electrode of the capacitor and the second voltage source； And

Reading circuit, the reading circuit are used for

The of the first electrode of the capacitor is read after the temporary period and in the support transistor turns One read-out voltage,

After first read-out voltage reading and when the first electrode of the capacitor is connected to the first voltage source The second read-out voltage of the first electrode of the capacitor is read, and

The voltage difference of first read-out voltage Yu second read-out voltage is calculated, to eliminate caused by the temporary period Noise voltage.

9. sensing circuit according to claim 8, wherein between the exposure period, the support transistor turns, with dimension The second electrode of the capacitor is held in second reset voltage.

10. a kind of operation method of sensing circuit, which includes optical diode, connects the overall situation of the optical diode fastly Door transistor, is connected to institute at the charge transfer transistor being connected between the global shutter transistor and floating diffusion nodes State the rear end of the capacitor and the connection floating diffusion nodes between global shutter transistor and the charge transfer transistor Reset transistor, the operation method includes:

Into first mode, wherein in the first mode, by sequentially opening the rear end reset transistor and the charge Transfer control transistor is so that reading circuit reads the first reset voltage and the first photoreceptor voltage respectively；And

Into second mode, wherein the global shutter transistor is connected always, and by sequentially opening in the second mode The rear end reset transistor and electric charge transfer control transistor are so that the reading circuit reads the second resetting electricity respectively Pressure and the second photoreceptor voltage.

11. operation method according to claim 10, also includes:

Into the third mode, wherein the charge transfer transistor is connected always, and by sequentially opening in the third mode The global shutter transistor and the rear end reset transistor so that the reading circuit read respectively third photoreceptor voltage and Third reset voltage.

12. operation method according to claim 10, wherein the sensing circuit also includes to be connected to the 4th reset voltage With the reset transistor between the optical diode, the operation method also includes:

Into fourth mode, wherein the electric charge transfer control transistor and the overall situation are connected always in the fourth mode Shutter transistor simultaneously closes the rear end reset transistor always, and by opening and closing the reset transistor so that the reading is electric Road sequentially reads the 4th reset voltage and the 4th photoreceptor voltage.

13. a kind of sensing circuit, which includes:

Optical diode；

First electric charge transfer controls transistor；

Second electric charge transfer controls transistor；

First capacitor, the first capacitor are used for the storage resetting signal during temporary；

Second capacitor, second capacitor are used to store photosensitive signal in temporary period, wherein the first capacitor and described Second capacitor couples the optical diode simultaneously；

First floating diffusion point, the first floating diffusion point control transistor connection described first by first electric charge transfer Capacitor；

Second floating diffusion point, the second floating diffusion point control transistor connection described second by second electric charge transfer Capacitor；And

Reading circuit, the reading circuit are used for

After the temporary period from the first floating diffusion point read first it is temporary after signal and float from described second Diffusion point reads the second temporary rear signal,

According to described first it is temporary after signal calculate first repeat sample signal and according to described second it is temporary after signal calculate the Two repeat sample signal, and

The signal for calculating the first repetition sample signal and the second repetition sample signal is poor, to eliminate the temporary period Generated noise voltage.

14. sensing circuit according to claim 13, also brilliant comprising the first global shutter transistor and the second global shutter Body pipe, wherein

The first global shutter transistor is connected between the optical diode and the first capacitor,

The second global shutter transistor is connected between the optical diode and second capacitor, and

When the second global shutter transistor turns, the first global shutter transistor is closed.

15. sensing circuit according to claim 13, wherein the reading circuit is also used to

It is read respectively from the first floating diffusion point and the second floating diffusion point with reference to resetting signal,

Sample signal is repeated according to the reference resetting signal and the described first temporary rear signal calculating described first, and

Sample signal is repeated according to the reference resetting signal and the described second temporary rear signal calculating described second.

16. a kind of imaging sensor, which includes multiple pixel circuits of array arrangement, multiple pixel circuit Each includes:

Optical diode；

First pixel circuit, first pixel circuit include that first node is used to expose in the temporary period storage optical diode The photosensitive signal generated between photophase；

Second pixel circuit, second pixel circuit include second node for the exposure period in first pixel circuit Between and temporary period storage resetting signal；And

Reading circuit, the reading circuit are used for

After the temporary period from the first node read it is temporary after photosensitive signal and read from the second node temporary Signal is reset after depositing,

According to it is described it is temporary after photosensitive signal calculate first repeat sample signal and according to it is described it is temporary after resetting signal calculate the Two repeat sample signal, and

The signal for calculating the first repetition sample signal and the second repetition sample signal is poor, to eliminate the temporary period Generated noise voltage.

17. imaging sensor according to claim 16, wherein the first node and the second node are to float to expand It dissipates section or is connected to the node of capacitor.

18. imaging sensor according to claim 16, wherein

First pixel circuit also includes the first reset transistor and second pixel circuit also includes the second resetting crystal Pipe, and

During the exposure, first reset transistor is closed and second reset transistor is connected.

19. imaging sensor according to claim 16, wherein

First pixel circuit also includes the first global shutter transistor and second pixel circuit also includes second overall situation Shutter transistor, and

During the exposure, the first global shutter transistor turns and the second global shutter transistor closing.

20. imaging sensor according to claim 16, wherein the reading circuit is also used to from the first pixel electricity Road and second pixel circuit are read respectively with reference to resetting signal,

It calculates described first with the temporary rear photosensitive signal with reference to resetting signal according to described and repeats sample signal, and

Sample signal is repeated according to the reference resetting signal and resetting signal calculating described second after described keep in.

Technical field

The present invention relates to a kind of circuits for improving pixels sense efficiency, come by the inductive effects or adjacent pixel of capacitor Voltage differences caused by excess electron are replicated, are finally eliminated in circuit downstream, improve sensing efficiency whereby.It is of the invention special Not Shi Heyongyu various optical sensor, include sensor front-illuminated, backside-illuminated sensor and global shutter sensor.

Background technique

Known sensor can all be influenced by ambient noise, and make to sense efficiency reduction.By taking optical sensor as an example, Such as global shutter sensor, due to the characteristic of its global shutter, all photosensitive pixels of sensor can be completed at the same time exposure, expose Light data is read in batches again after temporary.It is photosensitive since the reading of different pixels has time difference, while in the readout process Element still may by ambient lasting stimulation and generate unexpected photosensitive noise, therefore the impression of more late reading It is influenced according to easier by such photosensitive noise.It is all electricity since the composition of photosensitive noise and the composition of exposure data are identical Lotus, once therefore form of electrical charges exposure data by photosensitive noise pollution, can not just be isolated, cause final image signal Distortion, namely sensing efficiency can reduce.

Similar situation may also appear in rolling shutter sensor, and only its waiting time is shorter, by ambient Influence degree may be smaller.

In order to solve problems, the present invention provides the improvement on sensing circuit, by the inductive effects or phase of capacitor Adjacent pixel replicates voltage differences caused by excess electron, finally eliminated in circuit downstream, improves sensing efficiency whereby.

Summary of the invention

The present invention relates to a kind of circuits for improving pixels sense efficiency, and capacitor to be arranged by the floating effect of capacitor On signal path, induction, or the multiple identical capacitors of setting are generated with the charge of floating diffusion nodes storage.By aforementioned Mode makes capacitor at the stage for waiting photosensitive signal to be read, and can synchronize charge caused by the photosensitive noise of induction and change, And then when reading signal, influence caused by photosensitive noise is offset.

The present invention is also about a kind of circuit for improving pixels sense efficiency, by setting two-stage floating diffusion nodes, wherein Level-one storage resetting signal (Vrst), in addition level-one stores photosensitive signal (Vsig), and it is corresponding respectively to configure at least one simultaneously Capacitor, physical characteristic having the same, such as area and shape, the concentration distribution for mixing impurity and fabrication schedule etc., whereby Allow the charge for coming floating diffusion node region that can be converted into voltage storage in capacitor, then produced by photosensitive noise Charge when causing reaction, in these capacitors can form identical influence simultaneously, may finally offset each other, improve sensing whereby Efficiency.

The present invention couples one by the position of floating diffusion nodes also about a kind of circuit for improving pixels sense efficiency Two electrode one of them of a capacitor, the capacitor are coupled to floating diffusion nodes, and in addition one is coupled to rear class or resetting electricity Pressure.The two electrodes physical characteristic having the same of the capacitor, such as area and shape, the concentration distribution and manufacture of mixing impurity Program etc. when whereby caused by the photosensitive noise, charge causes reaction, can be formed at the both ends of the capacitor identical simultaneously It influences, may finally offset each other, improve sensing efficiency whereby.

A kind of operation method of the present invention also about sensing circuit controls identical picture according to the control signal of line decoder Certain transistors in plain circuit are from and off always is exposed to during signal is read, to operate in different shutter moulds Formula achievees the effect that save power consumption.

The present invention configures two floating diffusion nodes in parallel in one pixel also about a kind of sensing circuit to support The charge caused by photosensitive noise that disappears influences, and improves sensing efficiency whereby.

The present invention also about a kind of pixel circuit, offsets photosensitive make an uproar using two floating diffusion nodes of adjacent pixel Charge caused by sound influences, and improves sensing efficiency whereby.

The present invention provides a kind of sensing circuit, includes optical diode, first capacitor, the second capacitor and reading circuit.Institute It states first capacitor and connects the first floating diffusion nodes, the photosensitive signal generated for storing the optical diode during temporary. Second capacitance connection, second floating diffusion nodes, in the temporary period storage resetting signal.The reading circuit For resetting signal after keeping in after the temporary period from second floating diffusion nodes reading and being floated from described first It moves diffusion node and reads the news kept in rear photosensitive signal and calculate resetting signal and photosensitive signal after described keep in after described keep in Number difference, to eliminate noise voltage caused by the temporary period.

The present invention also provides a kind of sensing circuits, include optical diode, the first voltage source with the first reset voltage, tool There are the second voltage source, capacitor, rear end reset transistor and the reading circuit of the second reset voltage.The capacitor has the first electricity Pole and second electrode, the first electrode are coupled to floating diffusion nodes and have the optical diode when starting during temporary The photoreceptor voltage of generation, the second electrode have second reset voltage when the temporary period starts, wherein described First electrode and the second electrode have same object characteristic.The rear end reset transistor is connected to the second voltage source Between the second electrode of the capacitor.The reading circuit is used for after the temporary period and in the capacitor The first electrode reads the first read-out voltage of the second electrode of the capacitor, In when being connected to the first voltage source Institute is read after first read-out voltage is read and when the second electrode of the capacitor is connected to the second voltage source It states the second read-out voltage of the second electrode of capacitor and calculates first read-out voltage and second read-out voltage Voltage difference, to eliminate noise voltage caused by the temporary period.

The present invention also provides a kind of sensing circuits, include optical diode, the first voltage source with the first reset voltage, tool There is the second voltage source of the second reset voltage, capacitor, support transistor and reading circuit.The capacitor have first electrode and Second electrode, the first electrode couple floating diffusion nodes and when starting during temporary there is the optical diode to expose The photoreceptor voltage that period generates, the second electrode have second reset voltage when the temporary period starts, wherein The first electrode and the second electrode have same object characteristic.The support transistor is connected to the described of the capacitor Between second electrode and the second voltage source.The reading circuit is used for after the temporary period and in the support crystalline substance Body pipe be connected when read the capacitor the first electrode the first read-out voltage, first read-out voltage reading after and The of the first electrode of the capacitor is read when the first electrode of the capacitor is connected to the first voltage source Two read-out voltages and the voltage difference for calculating first read-out voltage and second read-out voltage, to eliminate the temporary period Generated noise voltage.

The present invention also provides a kind of operation method of sensing circuit, which includes optical diode, the connection light The global shutter transistor of diode, the electric charge transfer being connected between the global shutter transistor and floating diffusion nodes are brilliant Body pipe, the capacitor being connected between the global shutter transistor and the charge transfer transistor and the connection floating The rear end reset transistor of diffusion node.The operation method includes: entering first mode, wherein leading in the first mode After sequentially open the rear end reset transistor and the electric charge transfer control transistor so that reading circuit reads first respectively Reset voltage and the first photoreceptor voltage；And enter second mode, wherein being connected always described global fast in the second mode Door transistor, and transistor is controlled so that the reading by sequentially opening the rear end reset transistor and the electric charge transfer Circuit reads the second reset voltage and the second photoreceptor voltage respectively.

The present invention provides a kind of sensing circuit, turns comprising optical diode, the first electric charge transfer control transistor, the second charge Move control transistor, first capacitor, the second capacitor, the first floating diffusion point, the second floating diffusion point and reading circuit.It is described First capacitor is used for the storage resetting signal during temporary.Second capacitor is used to store photosensitive news in the temporary period Number, wherein the first capacitor and second capacitor couple the optical diode simultaneously.The first floating diffusion point passes through The first electric charge transfer control transistor connects the first capacitor.The second floating diffusion point passes through second charge Transfer control transistor connects second capacitor.The reading circuit is used for floating from described first after the temporary period Dynamic diffusion point read first it is temporary after signal and from the second floating diffusion point read second it is temporary after signal, according to described the Signal calculating second repeats sample signal after one temporary rear signal calculates the first repetition sample signal and keeps according to described second, And calculating described first repeats sample signal and the signal of the second repetition sample signal is poor, to eliminate the temporary period institute The noise voltage of generation.

The present invention also provides a kind of imaging sensors of multiple pixel circuits comprising array arrangement.Multiple pixel circuit Each include optical diode, the first pixel circuit, the second pixel circuit and reading circuit.The first pixel circuit packet It is used to store the photosensitive signal that the optical diode generates during exposure during temporary containing first node.Second pixel Circuit is used for during the exposure of first pixel circuit comprising second node and the temporary period storage resetting news Number.The reading circuit be used to after the temporary period read from the first node it is temporary after photosensitive signal and from described Signal is reset after second node reading is temporary, the first repetition sample signal is calculated and according to institute according to the temporary rear photosensitive signal It states resetting signal after keeping in and calculates the second repetition sample signal, and calculate the first repetition sample signal and described second and repeat The signal of sample signal is poor, to eliminate noise voltage caused by the temporary period.

Technological means provided by the present invention is also applicable to be able to use in sensing circuit of the invention to other, whereby Improve sensing efficiency.The present invention is particularly suitable in global shutter sensor, because its whole pixel is to complete to expose in the same time Light is then read in batches again, and the signal read more afterwards may more be affected.The present invention except be applicable to sensor front-illuminated with Outside, it is also particularly suitable for use in backside-illuminated sensor, because of its light-receiving area large percentage, has more multi-environment light that may cause to make an uproar Sound.

In order to which above and other objects, features and advantages of the invention can be become apparent from, will hereafter be illustrated appended by cooperation, in detail Carefully it is described as follows.In addition, identical component is indicated in explanation of the invention with identical symbol, first stated clearly in this conjunction.

Detailed description of the invention

Figure 1A is the sensing circuit of first embodiment of the invention；

Figure 1B is the running signal of the transistor of the sensing circuit of Figure 1A；

Fig. 2A is the sensing circuit of second embodiment of the invention；

Fig. 2 B is the running schematic diagram of the transistor of the sensing circuit of Fig. 2A；

Fig. 2 C is the timing diagram of the voltage change of the capacitance electrode of the sensing circuit of Fig. 2A；

Fig. 3 A is the sensing circuit of third embodiment of the invention；

Fig. 3 B is the running schematic diagram of the transistor of the sensing circuit of Fig. 3 A；

Fig. 3 C is the timing diagram of the voltage change of the capacitance electrode of the sensing circuit of Fig. 3 A；

Fig. 4 A is the sensing circuit of fourth embodiment of the invention；

Fig. 4 B is the running schematic diagram of the transistor of the sensing circuit of Fig. 4 A；

Fig. 4 C is the timing diagram of the voltage change of the capacitance electrode of the sensing circuit of Fig. 4 A；

Fig. 5 A is the sensing circuit of fifth embodiment of the invention；

Fig. 5 B is the running schematic diagram of the transistor of the sensing circuit of Fig. 5 A in different modes；

Fig. 6 A is the sensing circuit of sixth embodiment of the invention；

Fig. 6 B is the running schematic diagram of the transistor of the sensing circuit of Fig. 6 A；

Fig. 7 is the sensing circuit of seventh embodiment of the invention；

Fig. 8 is the sensing circuit of eighth embodiment of the invention.

Description of symbols

11,12,21,31,41 electric charge transfers control transistor

13,14,23,33,43 transistor

24,34 rear end reset transistor

15,25,35,45 reset transistor

16,26,36,46 transistor

17,27,37,47 optical diode

101,102,201,301 transistor is removed

44 support transistor

Specific embodiment

It is an object of the invention to cause by the inductive effects of capacitor to replicate excess electron using the improvement on circuit Voltage differences, finally eliminated, improve sensing efficiency whereby.Due in optical sensor circuit, in rotine exposure The charge for generating in time and being not yet read can be temporarily stored in floating diffusion nodes, these charges are once photosensitive Influence of noise just can not correctly parse conventional exposure numerical value, therefore how to avoid these charges of photosensitive influence of noise is most One of important project.The separate embodiment that following present invention is proposed, in other embodiments, can arrange in pairs or groups each other makes With effect can be played.

Technology of the invention is to will receive the characteristic that charge influences and generates voltage difference using capacitor, arranges in pairs or groups can control and make The capacitance parameter made can be in two electrodes of same capacitor, Huo Zhe when extraneous photosensitive noise enters photosensitive pixel circuit On multiple capacitors, identical noise voltage is induced, thus, so that it may by the method for circuit design, by noise voltage It deducts, improves sensing efficiency.

Figure 1A is painted the sensing circuit of the first embodiment of the present invention, and it makes use of two identical capacitors 101,102 to exist Temporary period stores resetting signal and photosensitive signal respectively.When photosensitive noise generate when, can simultaneously influence two capacitors 101, 102, namely reset signal and photosensitive signal and will receive the influence of same degree, then subsequent conditioning circuit is used just when reading Noise voltage can be deducted, improve sensing efficiency.Further illustrate that running content is as follows.

Referring to Figure 1B.Firstly, in stage I, reset transistor 15, electric charge transfer control transistor 11 and charge (turn-on) is connected in transfer control transistor 12, and resetting signal at this time will be stored in the second floating diffusion nodes FD2's of connection Capacitor 102.

Then, in stage II, reset transistor 15 and electric charge transfer control transistor 12 are closed into (turn-off), only It keeps electric charge transfer control transistor 11 to be connected, starts simultaneously at exposure program.The charge that optical diode 17 incudes can pass through charge Transfer control transistor 11 is moved to the first floating diffusion nodes FD1, and stores photosensitive signal Vsig in capacitor 101.Due to electricity Lotus transfer control transistor 12 is closed, the voltage V of the second floating diffusion nodes FD2_FD2It is maintained Vrst.

In stage III after end exposure, closes reset transistor 15, electric charge transfer control transistor 11 and charge and turn Move control transistor 12.At this point, the voltage V of the first floating diffusion nodes FD1_FD1=Vsig, i.e., voltage caused by photosensitive signal are strong Degree；And V_FD2=Vrst, i.e. voltage strength caused by resetting signal.

In the temporary period for the stage IV for waiting signal to be read, it can be produced when FD1 is affected by ambient light with FD2 Raw noise charge, since capacitor 101 and 102 is the two electric of identical (including size, mixing condition, optical angle etc.) Hold, therefore influence of the noise charge for photosensitive signal Vsig and the influence for resetting signal Vrst can be identical.It is making an uproar In the case that Acoustic Charge causes voltage to decline Δ v, V in period is kept in_FD1It will become Vsig- Δ v, and V_FD2It will become Vrst- Δ v。

Then, reading circuit reads V by transistor 13_FD2Voltage, i.e. Vrst- Δ v.Then, in stage V, electric conduction Lotus transfer control transistor 12 is so that Vsig- Δ v is transferred to capacitor 102.Reading circuit reads V by transistor 13_FD1Voltage, That is Vsig- Δ v.Subsequent conditioning circuit (such as reading circuit, but be not limited to) subtract each other two voltages of reading, it can be obtained Vsig- Vrst numerical value, and noise voltage Δ v is deducted.Reading circuit for example is respectively used to store before additive operation with two capacitors Vrst- Δ v and Vsig- Δ v.

In the present embodiment, transistor 13,14 and 16 be as a simple driving circuit, such as source follower, The feature of circuit can't be changed, therefore equivalent displacement can be done without will affect effect of the invention.

Fig. 2A is painted the sensing circuit of the second embodiment of the present invention, couples an electricity in the position of floating diffusion nodes Hold 201, two electrode one of them FD-in of the capacitor 201 are coupled to floating diffusion nodes, after in addition one FD is coupled to Grade.The two electrodes physical characteristic having the same of the capacitor 201, such as area and shape, the concentration distribution for for example mixing impurity With fabrication schedule etc., when charge causes reaction whereby caused by the photosensitive noise, phase can be formed at the both ends of capacitor 201 simultaneously Same influence, can finally offset each other in subsequent conditioning circuit, improve sensing efficiency whereby.Further illustrate that running content is as follows.

Referring to Fig. 2 B and 2C.Firstly, in stage I, reset transistor 25, electric charge transfer control transistor 21 and (turn-on) is connected in rear end reset transistor 24, and resetting signal at this time will make the current potential of FD be set in reset voltage Vay, and the current potential of FD-in is set to Vrst.

Then, in stage II, reset transistor 25 is closed into (turn-off), only electric charge transfer is kept to control transistor 21 are connected with rear end reset transistor 24, start exposure program at this time.The voltage of FD-in voltage and optical diode 27 interlocks, sense The charge answered can be through the electric charge transfer control accumulation of transistor 21 in FD-in node, so that the voltage of FD-in node is changed by Vrst Become photoreceptor voltage Vsig.Simultaneously as rear end reset transistor 24 is still connected, the voltage of FD node remains within resetting electricity Press Vay.

After end exposure, reset transistor 25, electric charge transfer control transistor 21 and rear end reset transistor 24 are closed, Voltage=Vsig of FD-in node at this time, the voltage of FD node remain within Vay, namely the FD-in when starting during temporary The voltage of node is Vsig and the voltage of FD node is Vay.In the temporary period for the stage III for waiting signal to be read, when When the voltage of FD-in node and the voltage of FD node are affected by ambient light and change, noise charge is for FD-in node Voltage is identical as the influence meeting of the voltage of FD node, in the case where noise charge causes voltage to decline, the voltage of FD-in node It will become Vsig- Δ v, and the voltage of FD node will become Vay- Δ v.

Then, in stage IV, conducting reset transistor 25 and electric charge transfer control transistor 21 and close rear end resetting Transistor 24, at this time because FD node is quick condition (floating), 201 both ends cross-pressure of capacitor can be consistent.When FD-in node Voltage when changing into Vrst by Vsig- Δ v, the voltage variety of FD node can be identical as the voltage variety of FD-in node And Vay+ (Vrst-Vsig) is changed by Vay- Δ v.Reading circuit reads the voltage value Vay+ of FD node in stage V (Vrst-Vsig)。

Then in stage VI, then rear end reset transistor 24 is connected so that the voltage of FD node is reset back to Vay.Meanwhile Since reset transistor 25 and electric charge transfer control transistor 21 maintain conducting, the voltage of FD-in node is maintained Vrst.It reads Circuit reads the voltage value Vay of FD node in stage VII.

Finally, using subsequent conditioning circuit, such as reading circuit, two read-out voltages are subtracted each other, can be obtained Vrst-Vsig number Value, and noise voltage Δ v is deducted.

In the present embodiment, transistor 23 and 26 is as a simple driving circuit, such as source follower, not The feature of circuit can be changed, therefore equivalent displacement can be done without will affect effect of the invention.

Fig. 3 A is painted the sensing circuit of the third embodiment of the present invention, couples one by the position of floating diffusion nodes Two electrode one of them FD-in of capacitor 301, the capacitor 301 are coupled to floating diffusion nodes, after in addition one FD is coupled to Grade.The two electrodes physical characteristic having the same of capacitor 301, such as area and shape, the concentration distribution and manufacture of mixing impurity Program etc. when charge causes reaction whereby caused by the photosensitive noise, can form identical shadow at the both ends of capacitor 301 simultaneously It rings, can finally offset each other in subsequent conditioning circuit, improve sensing efficiency whereby.The difference of 3rd embodiment and second embodiment, most Removing transistor (dump transistor) 341 has mainly also been coupled on FD-in node is connected to reset voltage source Between Vref1 and the left electrodes of capacitor 301, further illustrate that running content is as follows.

Referring to Fig. 3 B and 3C.Firstly, reset transistor 35, electric charge transfer control transistor 31, removing transistor 341 and rear end reset transistor 34 be connected (turn-on), at this time reset voltage setting FD node current potential in reset voltage Vref2, and the current potential of FD-in node is set in reset voltage Vref1.

Then, in stage II, by reset transistor 35 and the closing of transistor 341 (turn-off) is removed, only keeps electricity Lotus transfer control transistor 31 and rear end reset transistor 34 are connected, and start simultaneously at exposure program.The voltage and light of FD-in node The voltage of diode 37 interlocks, and the charge of induction can be accumulated through electric charge transfer control transistor 31 in FD-in node, so that The voltage of FD-in node changes into photoreceptor voltage Vsig by Vref1, and since rear end reset transistor 34 is still connected, FD node Voltage remain within reset voltage Vref2.

After end exposure, close reset transistor 35, electric charge transfer control transistor 31, remove transistor 341 and after Reset transistor 34 is held, voltage=Vsig of FD-in node, the voltage of FD node remain within Vref2 at this time, namely temporary The voltage of FD-in node is Vsig when starting during depositing and the voltage of FD node is Vref2.In the stage for waiting signal to be read In the temporary period of III, when the voltage of the voltage of FD-in node and FD node is affected by ambient light and changes, noise Charge is identical for the voltage of FD-in node and the influence meeting of the voltage of FD node.In the feelings that noise charge causes voltage to decline Under condition, the voltage of FD-in node will become Vsig- Δ v, and the voltage of FD node will become Vref2- Δ v.

Then, in stage IV, transistor 341 is removed in conducting, at this time because FD node is quick condition (floating), 301 both ends cross-pressure of capacitor can be consistent.When the voltage of FD-in node changes into Vref1 by Vsig- Δ v, the voltage of FD node becomes Change amount can be identical as the voltage variety of FD-in node, and changes into Vref2+ (Vref1-Vsig) by Vref2- Δ v.It reads Circuit reads the voltage value Vref2+ (Vref1-Vsig) of FD node by transistor 33 in stage V.

Then, it in stage VI, turns off and removes transistor 341, while starting resetting transistor 35, electric charge transfer control The voltage of FD node is reset back to Vref2 and changes into the voltage of FD-in node by transistor 31 and rear end reset transistor 34 Vrst。

In the stage VII of next step, starting resetting transistor 35 and removing transistor 341 simultaneously close off electric charge transfer Transistor 31 and rear end reset transistor 34 are controlled, in this condition, because FD node is quick condition (floating), electricity Holding 301 both ends cross-pressures can be consistent.When the voltage of FD-in node changes into Vref1 by Vrst, the voltage variety meeting of FD node It is identical as the voltage variety of FD-in node, Vref2+ (Vref1-Vrst) is changed by Vref2.Reading circuit passes through crystal Pipe 33 reads the voltage value Vref2+ (Vref1-Vrst) of FD node in stage VIII.

Finally, using subsequent conditioning circuit, such as reading circuit, two read-out voltages are subtracted each other, can be obtained Vrst-Vsig number Value, and noise voltage Δ v is deducted.

In the present embodiment, transistor 33 and 36 is as a simple driving circuit, such as source follower, not The feature of circuit can be changed, therefore equivalent displacement can be done without will affect effect of the invention.

Fig. 4 A is painted the sensing circuit of the fourth embodiment of the present invention, couples one by the position of floating diffusion nodes Two electrode one of them FD of capacitor 401, the capacitor 401 are coupled to floating diffusion nodes, and in addition one FD-neg is coupled to Source/drain of transistor 44, the support transistor 44 is supported to be connected to reset voltage Vref.Two electrodes of capacitor 401 have phase With physical characteristic, such as area and shape, such as the concentration distribution and fabrication schedule of mixing impurity, whereby when photosensitive noise When generated charge causes reaction, identical influence can be formed at the both ends of the capacitor 401 simultaneously, it finally can be in subsequent conditioning circuit It offsets each other, improves sensing efficiency whereby.Further illustrate that running content is as follows.

Referring to Fig. 4 B and 4C.Firstly, in stage I, reset transistor 45, electric charge transfer control transistor 41 and Support transistor 44 that (turn-on) is connected, the current potential of FD node will be set in reset voltage Vrst by resetting signal at this time, and The current potential of FD-neg node is set to Vref.

Then, in during the exposure of stage II, reset transistor 45 is closed into (turn-off), only keeps electric charge transfer It controls transistor 41 and transistor 44 is supported to be connected, start simultaneously at exposure program, the voltage of FD node and the electricity of optical diode 47 Pressure interlocks, and the charge of induction can be accumulated through electric charge transfer control transistor 41 in FD node, so that the voltage of FD node is exposing Vrst is maintained when light is incipient (if considering the coupled voltages Va of reset transistor 45, for Vrst-Va) and to expose Period is changed into Vsig；And due to supporting transistor 44 to maintain conducting, the voltage of FD-neg node maintains Vref.

After end exposure, closes reset transistor 45, electric charge transfer control transistor 41 and support transistor 44, at this time Voltage=Vsig of FD node is (if consider the coupled voltages Va of reset transistor 45, for Vsig-Va), the electricity of FD-neg node Pressure remains within Vref, namely the voltage of FD node is Vsig and FD-neg when starting during terminating during exposure and is temporary The voltage of node is Vref.In the temporary period for the stage III for waiting signal to be read, the voltage and FD-neg of FD node are saved The voltage of point may be subjected to the influence of environment light and change, and noise charge is for the voltage and FD-neg node of FD node The influence of voltage can be identical, and in the case where noise charge causes voltage to decline Δ v, the voltage of FD node will become Vsig- Δ v If (considering the coupled voltages Va of reset transistor 45, for Vsig-Va- Δ v), and the voltage of FD-neg node will become Vref-Δv。

Then, it in stage IV, under the feelings for maintaining reset transistor 45 and electric charge transfer control transistor 41 to close, leads Logical to support transistor 44, in the moment for supporting transistor 44 to be connected, the voltage of FD-neg node changes into Vref by Vref- Δ v, At this time because the cross-pressure at 401 both ends of capacitor is unable to instantaneous variation, the variable quantity of the voltage of FD node can be with FD-neg node Variable quantity it is identical, Vsig is changed by Vsig- Δ v.At this point, reading circuit can read FD node by transistor 43 Voltage value Vsig.

Then, in stage V, then reset transistor 45 and electric charge transfer control transistor 41 is connected with by the electricity of FD node Ballast puts back into Vrst.In stage VI, closes reset transistor 45 and electric charge transfer controls transistor 41, reading circuit passes through crystalline substance The voltage Vrst of the reading FD node of body pipe 43.Finally, using subsequent conditioning circuit, such as reading circuit, by two read-out voltage phases Subtract, can be obtained Vrst-Vsig numerical value, and noise voltage Δ v is deducted.

In the present embodiment, transistor 43 and 46 is as a simple driving circuit, such as source follower, not The feature of circuit can be changed, therefore equivalent displacement can be done without will affect effect of the invention.

Referring to figure 5. shown in A, it is the sensing circuit of fifth embodiment of the invention, starts operation (example in a pixel Such as reset optical diode) it is read to pixel data, it is always on or closes always electric charge transfer control transistor 51, rear end weight Transistor 54 or global shutter transistor 58 are set, to operate in different shutter modes.Transistor 53 is a simple driving electricity Road, such as source follower can't change the feature of circuit, can the equivalent replacement effect of the invention without influence.Each member The connection type of part is shown in Fig. 5 A.

Referring to Fig. 5 B, for example, in the global shutter imaging sensor mode using correlated double sampling technology (CDS) In (such as being known as first mode), the exposure data of optical diode 57 is stored in capacitor when global shutter transistor 58 is connected To form exposure voltage Vsig in 501.Fig. 5 A pixel by line decoder choose (such as by row selection signal Rsel) after, Transistor 51 is controlled by sequentially opening rear end reset transistor 54 and electric charge transfer to allow reading circuit to read resetting electricity respectively Vres and exposure voltage Vsig is pressed, that is, reset voltage Vres is opened in rear end reset transistor 54 (closes electric charge transfer control Transistor 51) when be stored in FD for reading circuit reading, exposure voltage Vsig electric charge transfer control transistor 51 open (close Close rear end reset transistor 54) when from SD be transferred to FD for reading circuit reading.For example, the reading circuit includes two capacitors For storing reset voltage Vres and exposure voltage Vsig respectively.

For example, in the rolling shutter imaging sensor mode (such as being known as second mode) using correlated double sampling technology In, global shutter transistor 58 is switched on always, i.e., is not switched in operation.During exposure, the exposure of optical diode 57 Data storage forms exposure voltage Vsig in capacitor 501.Fig. 5 A pixel by line decoder choose (such as pass through row select Select signal Rsel) after, transistor 51 is controlled by sequentially opening rear end reset transistor 54 and electric charge transfer to allow reading respectively Circuit reads reset voltage Vres and exposure voltage Vsig, similar to described in first mode.Similarly, the reading circuit includes two electricity Hold for storing reset voltage Vres and exposure voltage Vsig respectively.

For example, in the global shutter imaging sensor mode (such as being known as the third mode) of 5T (5 transistors), charge Transfer control transistor 51 is switched on always.During exposure, the exposure data of optical diode 57 is in global shutter transistor 58 Floating diffusion nodes FD is stored in when conducting to be formed in exposure voltage Vsig.(example is chosen by line decoder in the pixel of Fig. 5 A Such as pass through row selection signal Rsel) after, by opening global shutter transistor 58 and rear end reset transistor 54 sequentially to distinguish Reading circuit is allowed to read exposure voltage Vsig and reset voltage Vres, that is, exposure voltage Vsig is in global shutter transistor 58 FD is stored in when opening and (closing rear end reset transistor 54) for reading circuit reading, reset voltage Vres resets brilliant in rear end Body pipe 54 is stored in FD for reading circuit reading when opening and (closing global shutter transistor 58).Similarly, the reading circuit Comprising two capacitors for storing exposure voltage Vsig and reset voltage Vres respectively.

For example, in the rolling shutter imaging sensor mode (such as being known as fourth mode) of 3T (3 transistors), charge Transfer control transistor 51 and global shutter transistor 58 are switched on always, and rear end reset transistor 54 is closed always, i.e., It is not switched in operation.During exposure, the exposure data of optical diode 57 is stored in floating diffusion nodes FD to be formed Exposure voltage Vsig.Fig. 5 A pixel by line decoder choose (such as by row selection signal Rsel) after, pass through opening and closing weight Transistor 54 is set to read reset voltage Vres and exposure voltage Vsig respectively.Similarly, the reading circuit is used comprising two capacitors In storage reset voltage Vres and exposure voltage Vsig respectively.

In the present embodiment, using the same circuit, it is brilliant that part can be always on or closed during the running of a pixel Body pipe is to operate in different shutter modes.

It please refers to shown in Fig. 6 A, is the sensing circuit of the dot structure of sixth embodiment of the invention, in a pixel Two floating diffusion point FD1 and FD2 of middle configuration and by timing control with read respectively it is different repeat sample signals, and after passing through Continuous circuit (such as reading circuit) repeats sample signal for these and carries out operation to deduct noise voltage, improves sensing efficiency.

Referring to Fig. 6 B, then illustrate the operation timing of the present embodiment.

In stage I, reset transistor 65 is connected to empty the charge of optical diode 67.Voltage source Vref maintains low level And rear end reset transistor 64A and 64B is connected and is not turned on transistor 63A and 63B.

In stage II, reset transistor 65 is closed, by exposure optical diode 67 with stored charge.Voltage source Vref is still It maintains low level and is not turned on transistor 63A and 63B.

In stage III, conducting electric charge transfer controls transistor 61A and 61B, and voltage source Vref is converted to high levle To reset the voltage of charge-storage diode SD1 and SD2 to Vref.

In stage IV, global shutter transistor 68B is connected with by the electric charge transfer of optical diode 67 to (or down to) electricity Hold in 601B so that storing photosensitive signal Vsig in capacitor 601B.Simultaneously as global shutter transistor 68A and do not turn on, Resetting signal Vref is still stored in capacitor 601A.In the present embodiment, capacitor 601A and 601B couple identical optical diode 67.

During the storage for the stage V for waiting signal to be read, it can be generated when SD1 is affected by ambient light with SD2 Noise charge.Since capacitor 601A and 601B are the electricity of identical (including size, mixing condition, optical angle etc.) Hold, therefore influence of the noise charge for Vsig and the influence for Vref can be identical.In the case where noise charge causes voltage In the case where dropping Δ v, the voltage V of capacitor 601A_SD1It will become and keep in rear signal Vref- Δ v, and the voltage V of capacitor 601B_SD2Meeting Signal Vsig- Δ v after becoming temporary.

In stage VI, the voltage of voltage source Vref is maintained high levle to reset floating diffusion nodes FD1 and FD2 Voltage is Vref.

In stage VII, reading circuit passes through transistor 63A and 63B respectively and reads floating diffusion nodes FD1 and FD2 Voltage Vref.The reading circuit for example stores the voltage of floating diffusion nodes FD1 and FD2 respectively comprising two capacitors Vref。

In stage VIII, conducting electric charge transfer control transistor 61A and 61B is respectively to turn the charge in SD1 and SD2 Move in (or down to) floating diffusion nodes FD1 and FD2 so that floating diffusion nodes FD1 and FD2 during storage after have respectively Have storage after signal Vref- Δ v and Vsig- Δ v, wherein Δ v be storage during in the voltage change as caused by environment light.

In stage IX, reading circuit passes through the storage that transistor 63A and 63B read floating diffusion nodes FD1 and FD2 respectively Deposit rear signal Vref- Δ v and Vsig- Δ v.

It is interrogated from the foregoing, it will be observed that reading circuit is sequentially read from floating diffusion nodes FD1 with reference to after resetting signal Vref and storage Number Vref- Δ v；And it is sequentially read from floating diffusion nodes FD2 with reference to signal Vsig- Δ v after resetting signal Vref and storage.Afterwards Continuous circuit subtracts each other two voltages of reading, can be obtained repetition sample signal Δ v (i.e. Vref-Vref+ Δ v) and Vref- Vsig+Δv.Subsequent conditioning circuit, which carries out subtraction calculating to two repetition sample signals again, can acquire Vref-Vsig.It can be seen that Noise voltage Δ v has been eliminated by calculus of differences.

The opening and closing of each transistor in the different phase of sixth embodiment is depicted in Fig. 6 B and the connection side of each element Formula is shown in Fig. 6 A.

Please refer to shown in Fig. 7, be seventh embodiment of the invention sensing circuit, the present embodiment be by adjacent pixel come Noise voltage Δ v is eliminated, such as Fig. 7 shows the pixel PIXA and PIXB of two adjacent columns.Firstly, reading circuit passes through column<m> (rear end reset transistor 74A is connected to reset to float and expand in the reference resetting signal Vrst that read line reads floating diffusion nodes FD1 Dissipate node FD1), and signal Vrst is reset (after conducting by the reference that the read line of column<m+1>reads floating diffusion nodes FD2 Hold reset transistor 74B to reset floating diffusion nodes FD2).Reset transistor 75A is for resetting optical diode 77A.

Then, during exposure, the photosensitive signal Vsig of the capacitor 701A storage optical diode 77A generation of pixel PIXA (conducting global shutter transistor 78A is to carry out charge accumulation)；Meanwhile the reset transistor 75B in pixel PIXB is persistently opened Or global shutter transistor 78B is continuously off so that capacitor 701B storage resetting signal Vrst, i.e. capacitor 701B do not store Photosensitive signal from optical diode 77B.

Capacitor 701A and 701B is stored in charge and by the temporary period before not being read, by ring optical noise It influences and generates voltage change Δ v.Since capacitor 701A and 701B are identical (including size, to mix condition, optics Angle etc.) capacitor, therefore influence of the noise charge for Vsig and the influence for Vrst can be identical.In the voltage Changes delta v is in the embodiment of voltage drop, be stored in after during storage capacitor 701A and 701B it is temporary after signal point It Bian Hua not be Vsig- Δ v and Vrst- Δ v.

Then, reading circuit reads the temporary rear signal Vsig- Δ v of floating diffusion nodes FD1 by the read line of column<m> (conducting charge transfer transistor 71A is to carry out electric charge transfer), and floating diffusion nodes are read by the read line of column<m+1> The temporary rear signal Vrst- Δ v of FD2 (conducting charge transfer transistor 7BA is to carry out lotus transfer).Subsequent conditioning circuit (such as read Circuit) the repetition sample signal of pixel PIXA can be calculated as Vrst-Vsig+ Δ v, and calculate the repetition sample signal of pixel PIXB For Vrst-Vrst+ Δ v, for example, by will refer to resetting signal subtract it is temporary after signal.Using circuit, such as reading circuit, into The subtraction of two repetition sample signals of row can then acquire Vrst-Vsig and eliminate noise voltage Δ v, improve sensing efficiency.

In the present embodiment, transistor 73A and 73B be as a simple driving circuit, such as source follower, and The feature of circuit will not be changed, therefore equivalent displacement can be done without will affect effect of the invention.

It please refers to shown in Fig. 8, is the sensing circuit of eighth embodiment of the invention, the present embodiment is again by adjacent picture Noise voltage Δ v is usually eliminated, such as Fig. 8 shows the pixel PIXA and PIXB of two adjacent columns.Firstly, reading circuit passes through column < m > read line read floating diffusion nodes FD1 reference resetting signal Vrst (be connected rear end reset transistor 84A it is floating to reset Dynamic diffusion node FD1), and signal Vrst is reset by the reference that the read line of column<m+1>reads floating diffusion nodes FD2 and (is led Lead to rear end reset transistor 84B to reset floating diffusion nodes FD2).Reset transistor 85A is for resetting optical diode 87A's Charge.

Then, during exposure, the photosensitive signal of the floating diffusion nodes FD1 storage optical diode 87A of pixel PIXA Vsig (conducting charge transfer transistor 81A stored charge)；Meanwhile reset transistor 85B and electric charge transfer in pixel PIXB Transistor 81B is persistently opened so that floating diffusion nodes FD2 storage resetting signal Vrst, i.e. floating diffusion nodes FD2 do not store up Deposit the photosensitive signal from optical diode 87B.

Floating diffusion nodes FD1 and FD2 are stored in charge and by the temporary period before not being read, by ring light The influence of noise and generate voltage change Δ v.Since FD1 is identical, influence of the noise charge for Vsig with FD2 And the influence for Vrst can be identical.In the embodiment that voltage change Δ v is voltage drop, by during storage The temporary rear signal for being stored in floating diffusion nodes FD1 and FD2 afterwards changes respectively as Vsig- Δ v and Vrst- Δ v.

Then, reading circuit reads the temporary rear signal Vsig- Δ of floating diffusion nodes FD1 by the read line of column<m> V, and the temporary rear signal Vrst- Δ v for passing through the read line of column<m+1>reading floating diffusion nodes FD2.Subsequent conditioning circuit (such as Reading circuit) the repetition sample signal of pixel PIXA can be calculated as Vrst-Vsig+ Δ v, and calculate the repetition sampling of pixel PIXB Signal is Vrst-Vrst+ Δ v, such as subtracts temporary rear signal by that will refer to resetting signal.Two repetitions are carried out using circuit The subtraction of sample signal can then acquire Vrst-Vsig and eliminate noise voltage Δ v, improve sensing efficiency.

In the present embodiment, transistor 83A and 83B be as a simple driving circuit, such as source follower, and The feature of circuit will not be changed, therefore equivalent displacement can be done without will affect effect of the invention.

In Fig. 7 and Fig. 8, due to being operated simultaneously using two column pixels, effective columns of sensing array is kept to half, That is the pixel of half, which is not used in, generates photosensitive signal.The sensing array includes multiple pixel circuits of array arrangement, such as PIXA And PIXB.

It should be noted that although Fig. 7 and Fig. 8 show the pixel running of two adjacent columns, the present invention not as Limit.In other embodiments, pixel PIXA and PIXB can be located at not two pixel columns of direct neighbor, two adjacent pixel columns Or not two pixel columns of direct neighbor.

In the embodiment of the present invention, assumes that the photosensitive signal stored by temporary period and reset signal by noise voltage It influences, and resetting signal is not equal to original resetting after making temporary rear photosensitive signal be not equal to original photosensitive signal and keep in Signal.

Different phase in the various embodiments described above refers to the different time intervals of pixel running.Above-mentioned each transistor all has Coupled voltages Va, it is known to those skilled in the art, therefore repeated no more in this.

According to the above description, it is to be understood that technological means provided by the present invention, which can utilize, to be needed temporarily to store through node On the sensing circuit of charge, although previous embodiment is the optical diode photosensitive circuit explanation to receive light generation charge, Also applicable on other sensor circuits, improve the situation that node is polluted by noise voltage whereby.

Although the present invention is disclosed by previous examples, it is not intended to limit the invention, belonging to any present invention There are usual knowledge technology personnel, without departing from the spirit and scope of the present invention, when various changes can be made in technical field With modification.Therefore protection scope of the present invention is subject to the range defined depending on appended claims.