CN109496427B - Image sensor and sensing method thereof - Google Patents
Image sensor and sensing method thereof Download PDFInfo
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- CN109496427B CN109496427B CN201880002085.3A CN201880002085A CN109496427B CN 109496427 B CN109496427 B CN 109496427B CN 201880002085 A CN201880002085 A CN 201880002085A CN 109496427 B CN109496427 B CN 109496427B
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04N25/00—Circuitry of solid-state image sensors [SSIS]; Control thereof
- H04N25/70—SSIS architectures; Circuits associated therewith
- H04N25/71—Charge-coupled device [CCD] sensors; Charge-transfer registers specially adapted for CCD sensors
- H04N25/75—Circuitry for providing, modifying or processing image signals from the pixel array
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04N25/00—Circuitry of solid-state image sensors [SSIS]; Control thereof
Abstract
The invention discloses an image sensor and a sensing method thereof, comprising a plurality of super pixels and a signal reading circuit; wherein the super-pixel comprises a plurality of pixels, each pixel comprising: light sensing component and sub-driving unit. The main driving unit is connected to the sub-driving units to read out the average sensing signal of the light sensing element in each pixel to obtain a more approximate actual average sensing signal; and each super pixel is connected with the signal reading circuit by only a single transmission line to read the average sensing signal, thereby reducing the number of the transmission lines and the layout area of the transmission lines.
Description
Technical Field
The present invention relates to an image sensor, and more particularly, to an image sensor having super pixels and a sensing method thereof.
Background
Currently, the image sensor is still affected by many different process factors, so in order to reduce noise interference in the sensing signal, a plurality of pixels may be combined into a super pixel (super pixel), for example, 4 pixels arranged in 2 × 2 are combined into a super pixel, and the average value of the voltage values sensed by the plurality of pixels in the super pixel represents the overall sensing result of the super pixel to improve the signal-to-noise ratio of the image sensor.
However, although the signal-to-noise ratio of the image sensor can be improved, each pixel still has to be connected to the signal reading circuit through one transmission line, and the wiring space occupied by the whole transmission line is still large, so that a solution is needed.
Disclosure of Invention
An objective of the present invention is to disclose an image sensor and a sensing method thereof to solve the above problems.
An embodiment of the present application discloses an image sensor. The image sensor includes a super pixel including: a plurality of pixels, wherein each of the pixels comprises: a light sensing component; the sub-driving units are respectively connected to the light sensing assemblies so as to drive the light sensing assemblies; the main driving unit is connected to the sub-driving units of the pixels so as to simultaneously read sensing signals after the sub-driving units drive the optical sensing elements; and the signal reading circuit is connected to the main driving unit of the super pixel so as to read the average sensing voltage of the light sensing components of the plurality of pixels.
A capacitor is connected between the main driving unit and each sub-driving unit, so that the voltage value sensed by each optical sensing assembly can be read after the optical sensing assembly is reset, and the actual average output voltage can be closer to; in addition, the average output voltage directly read by the signal reading circuit does not need to be subjected to complex operation, and the signal reading circuit is also beneficial to reducing the number of the transmission lines and reducing the layout area of the transmission lines.
An embodiment of the present application discloses a sensing method of an image sensor, wherein the image sensor includes a super pixel, the super pixel includes a plurality of pixels, each of the pixels includes a light sensing element, a sub-driving unit and a capacitor, the sensing method includes: (a) resetting the light sensing component and the capacitor of each pixel; (b) sensing the light sensing component in each pixel; (c) outputting the voltage of the light sensing component in each pixel to a capacitor, and reading the average voltage of the capacitor in each pixel; (d) resetting the capacitor in each pixel and reading out a reset voltage; and (e) calculating the average sensing voltage of the light sensing component in each pixel according to the average voltage and the reset voltage.
The voltage value sensed by each light sensing component can be read after the light sensing component is reset, and the actual average output voltage can be closer to; in addition, the average output voltage directly read by the signal reading circuit does not need to be subjected to complex operation, and the signal reading circuit is also beneficial to reducing the number of the transmission lines and reducing the layout area of the transmission lines.
An embodiment of the present application discloses another sensing method of an image sensor. The image sensor comprises a super pixel, the super pixel comprises a plurality of pixels, each pixel comprises a light sensing component, a sub-driving unit and a capacitor, and the sensing method comprises the following steps: (a) resetting the light sensing component of each pixel; (b) sensing the light sensing component in each pixel; (c) reading out a reset voltage during a sensing period; (d) after the sensing is finished, outputting the voltage of the light sensing component in each pixel to a capacitor, and reading the average voltage of the capacitor in each pixel; and (e) calculating the average sensing voltage of the light sensing component in each pixel according to the average voltage and the reset voltage.
The voltage value sensed by each light sensing component can be read after the light sensing component is reset, and the actual average output voltage can be closer to; in addition, the average output voltage directly read by the signal reading circuit does not need to be subjected to complex operation, and the signal reading circuit is also beneficial to reducing the number of the transmission lines and reducing the layout area of the transmission lines.
Drawings
Fig. 1 is a schematic structural diagram of an image sensor according to the present application.
FIG. 2 is a schematic structural diagram of a super-pixel in an image sensor according to a first embodiment of the present invention.
Fig. 3 is a control timing chart in cooperation with fig. 2.
FIG. 4 is a schematic structural diagram of a second embodiment of a super pixel in an image sensor according to the present application.
Fig. 5 is a control timing chart in cooperation with fig. 4.
FIG. 6 is a schematic structural diagram of a super pixel in an image sensor according to a third embodiment of the present invention.
Fig. 7 is a control timing chart in cooperation with fig. 6.
Wherein the reference numerals are as follows:
1. 1a, 1b image sensor
10 super pixel
11 light sensing assembly
12. 12a, 12b sub-drive unit
13 main drive unit
20 signal reading circuit
30. 30a, 30b controller
VCCR first reference voltage
VCCP second reference voltage
VREF third reference voltage
RST reset control signal
SELP first selection control signal
REF first control signal
Vb bias control signal
Q1 first reset switch
Q2 first output switch
Q3 first selection switch
Q4 second reset switch
Q5 first switch
Q6 second output switch
Q7 second selection switch
C capacitor
One end of the P1 capacitor
P2 the other end of the capacitor
PH1, PH2, PH3 phases
Texp exposure phase
CNT feedback capacitor
OP amplifier
Detailed Description
Certain terms are used throughout the description and following claims to refer to particular components. As one skilled in the art will appreciate, manufacturers may refer to a component by different names. In the present specification and the claims, the difference in name is not used as a means for distinguishing between components, but a difference in function of a component is used as a reference for distinguishing between components. In the following description and in the claims, the terms "include" and "comprise" are used in an open-ended fashion, and thus should be interpreted to mean "include, but not limited to.
In the image sensor and the sensing method thereof disclosed by the application, the driving circuit of each super pixel (super pixel) of the image sensor can directly average the sensing voltage of the light sensing elements of a plurality of pixels included in the driving circuit, so that the average output voltage of the plurality of pixels can be output only through a transmission line corresponding to the super pixel, and the sensing voltage of the plurality of pixels does not need to be read out through the transmission line. The following describes the technical contents of the image sensor and the sensing method thereof in detail with reference to a plurality of embodiments and drawings.
Referring to fig. 1 and 2, an image sensor 1 of the present application includes a plurality of super pixels 10 arranged in a matrix, a signal reading circuit 20, and a controller 30; wherein the super pixel 10 is connected to the signal reading circuit 20 and the controller 30. In the present embodiment, each super pixel 10 includes 4 pixels 14 arranged in a 2 × 2 matrix, and the super pixel 10 can directly obtain the average sensing voltage of the 4 pixels 14 through proper control, and read the average sensing voltage at a time through a transmission line L. It should be noted that the number or arrangement of the plurality of super-pixels 10 is not limited in the present invention, and the number or arrangement of the pixels 14 included in each super-pixel 10 is not limited in the present invention, and each super-pixel 10 may actually include any number of pixels 14 arranged in any manner.
Referring to fig. 2, which is a first embodiment of the image sensor 1 of the present application, only one of the plurality of super pixels 10 is shown, and each pixel 14 of the super pixels 10 includes a photo sensing device 11, a sub-driving unit 12 and a capacitor C; wherein the sub-driving unit 12 is connected between the photo sensing element 11 and the capacitor C. The super-pixel 10 utilizes a main driving unit 13 to read the average sensing voltage of the pixels 14 in the super-pixel 10, and the main driving unit 13 is connected to the sub-driving units 12 of each pixel 14 through the capacitor C in each pixel 14, i.e. the capacitor C is connected between the main driving unit 13 and each sub-driving unit 12. Preferably, the photo sensing device 11 is a photodiode.
The sub-driving unit 12 includes a first reset switch Q1, a first output switch Q2, a first selection switch Q3 and a second reset switch Q4. In the embodiment, the first reset switch Q1, the first output switch Q2, the first selection switch Q3 and the second reset switch Q4 are NMOS transistors, the first reset switch Q1 is connected in series between a first reference voltage VCCR and the negative terminal of the photo sensing device 11, the gate of the first reset switch Q1 is connected to a reset control signal RST, and the positive terminal of the photo sensing device 11 is connected to the ground voltage. The first output switch Q2 is configured as a source follower for driving the voltage of the negative terminal of the photo sensing device 11 to the next stage, specifically, the gate of the first output switch Q2 is connected to the negative terminal of the photo sensing device 11, and the first output switch Q2, the first selection switch Q3 and the second reset switch Q4 are sequentially connected in series between a second reference voltage VCCP and the ground voltage. The first selection switch Q3 is connected between the first output switch Q2 as a source follower and the capacitor C, and the gate of the first selection switch Q3 is connected to a first selection control signal SELP. The second reset switch Q4 is connected between the capacitor C and the ground voltage, and the gate of the second reset switch Q4 is connected to a bias control signal Vb.
The main driving unit 13 includes a first switch Q5, a second output switch Q6 and a second selection switch Q7. In the embodiment, the first switch Q5, the second output switch Q6 and the second selection switch Q7 are NMOS transistors, and the first switch Q5 is connected between a third reference voltage VREF and each pixel 14, specifically, the capacitor C of each pixel 14 is connected between the sub-driving unit 12 and the first switch Q5 of the same pixel 14. The gate of the first switch Q5 is connected to a first control signal REF. The second output switch Q6 is configured as a source follower for pushing the voltage at the P2 end of the capacitor C to the next stage, the second output switch Q6 and the second selection switch Q7 are serially connected between the second reference voltage VCCP and the transmission line L, and the gate of the second output switch Q6 is connected to the sub-driving unit 12 of each pixel 14 through the capacitor C of each pixel 14. The gate of the second selection switch Q7 is connected to a second selection control signal SEL.
It should be noted that the first reference voltage VCCR, the second reference voltage VCCP, and the third reference voltage VREF may be the same or different voltages from each other.
In the present embodiment, the controller 30 generates a reset control signal RST, a first selection control signal SELP, a bias control signal Vb, a first control signal REF, and a second selection control signal SEL to each of the sub-driving units 12 and the main driving unit 13.
Referring to fig. 3, the controller 30 controls the super-pixel 10 according to the timing chart shown in the figure, so that the signal reading circuit 20 can obtain the average output voltage of the super-pixel 10 through the transmission line L. The step of the controller 30 controlling the super pixel 10 and the signal reading circuit 20 includes: (a) entering an initial phase PH 1; (b) ending the initial phase PH1, and entering an exposure phase Texp; (c) after the exposure phase Texp is over, entering a first reading phase PH 2; (d) after the first reading phase PH2 ends, enter a second reading phase PH 3; and (e) calculating an average sense voltage.
In the initial stage PH1 in the above step (a), the controller 30 controls the first reset switch Q1, the first selection switch Q3, the second reset switch Q4, and the first switch Q5 of the main driving unit 13 of each sub-driving unit 12 to be turned on to reset the photo sensing element 11 and the capacitor C, so that the voltage of the end P1 of the capacitor C close to the photo sensing element 11 is reset to a reset voltage VRST, and the voltage of the end P2 of the capacitor C close to the photo sensing element 11 is reset to a third reference voltage VREF. Next, in the step (b), in the exposure stage Texp, the photo sensing device 11 performs exposure to sense the image intensity, that is, the photo sensing device 11 converts the intensity of the external light into a corresponding voltage.
In the step (C) of the first reading phase PH2, the controller 30 controls the first selection switch Q3 of each sub-driving unit 12 to be turned on, so that the voltage of the photo sensing device 11 is instantly converted into charges through the first output switch Q2 and accumulated at the P1 end of the capacitor C, and the voltage at the P1 end of the capacitor C becomes the sensing voltage VSIG to reflect the sensing voltage of the corresponding photo sensing device 11, and since a voltage difference (sensing voltage VSIG-reset voltage VRST) is instantly generated at the P1 end of the capacitor C, the voltage difference will be reflected on the existing third reference voltage VREF at the P2 end of the capacitor C to form VREF + (VSIG-VRST). Since the P2 terminals of the capacitor C of each pixel 14 in the super-pixel 10 are connected to each other, the P2 terminals of the capacitor C of each pixel 14 in the super-pixel 10 are automatically averaged with each other. That is, in the first reading phase PH2, the second selection switch Q7 is turned on, and the average value of the P2 terminal of the capacitor C of each pixel 14 in the super-pixel 10 is pushed to the signal reading circuit 20 through the second output switch Q6 as a source follower, so that the controller 30 can drive the signal reading circuit 20 to read the average output voltage Vout of all 4 photo sensing elements 11 in the super-pixel 10, as shown in the following formula (1):
step (d) in the second reading phase PH3, the controller 30 controls the first switch Q5 of the main driving unit 13 to be turned on again to reset the P2 terminal of the capacitor C to be the third reference voltage VREF; the controller 30 also controls the second selection switch Q7 to be turned on and the driving signal reading circuit 20 to read the third reference voltage VREF.
In the step (e), the average sensing voltage Vout 'of the photo sensing elements 11 of the super-pixel 10 is calculated according to the average output voltage Vout and the third reference voltage VREF, and the average sensing voltage Vout' of the sensing pixel 10 is obtained by subtracting the third reference voltage VREF from the obtained average output voltage Vout, as shown in the following formula (2). Therefore, the signal reading circuit 20 of the present application only performs simple operation, does not occupy excessive operation resources, and can reduce the number of transmission lines and the hardware area.
Referring to fig. 4, a second embodiment of the image sensor of the present application is substantially the same as the first embodiment shown in fig. 2, but each sub-driving unit 12a of the image sensor 1a further includes a transmission switch Q8, the transmission switch Q8 is connected in series between the first reset switch Q1 and the corresponding negative terminal of the photo sensing device 11, and the gate of the transmission switch Q8 is connected to a transmission control signal TX. The controller 30a provides a transmission control terminal TX.
Referring to FIG. 5, the controller 30a controls the super-pixel 10 shown in FIG. 4 according to the timing diagram shown in FIG.. The step of the controller 30a controlling the super pixel 10 and the signal reading circuit 20 includes: (a) enter a reset phase PH 1; (b) ending the reset phase PH1, and entering an exposure phase Texp; (c) entering a first read phase PH2 during the exposure phase Texp; (d) after the first reading stage is finished, ending the exposure time Texp, and entering a second reading stage PH 3; and (e) calculating an average sense voltage.
In the reset phase PH1, the controller 30a controls the first reset switch Q1 and the transmission switch Q8 of each sub-driving unit 12a to be turned on to reset the photo sensing device 11. Then, in step (b), the photo sensor device 11 starts to perform exposure to sense the image intensity, i.e. the photo sensor device 11 converts the external light intensity into a corresponding voltage magnitude.
In the step (C) of the first reading phase PH2, the controller 30a controls the first reset switch Q1, the first selection switch Q3, the second reset switch Q4 of each sub-driving unit 12a and the first switch Q5 of the main driving unit 13 to be turned on, so that the voltage of the end P1 of the capacitor C close to the photo sensing device 11 is reset to a reset voltage VRST, and the voltage of the end P2 of the capacitor C close to the photo sensing device 11 is reset to a third reference voltage VREF; meanwhile, the second selection switch Q7 of the main driving unit 13 is controlled to be turned on and drive the signal reading circuit 20 to read the reference voltage VREF.
In the step (d), in the second reading phase PH3, the controller 30a controls the transfer switch Q8 and the first selection switch Q3 of each sub-driving unit 12a to be turned on; the voltage of the photo sensing device 11 is instantaneously converted into charges through the transfer switch Q8 and the first output switch Q2 and accumulated at the P1 end of the capacitor C, so that the voltage at the P1 end of the capacitor C becomes the sensing voltage VSIG to reflect the sensing voltage of the corresponding photo sensing device 11, and since the P1 end of the capacitor C instantaneously generates a voltage difference (sensing voltage VSIG — reset voltage VRST), the voltage difference is reflected on the existing third reference voltage VREF at the P2 end of the capacitor C to form VREF + (VSIG-VRST). Since the P2 terminals of the capacitor C of each pixel 14 in the super-pixel 10 are connected to each other, the P2 terminals of the capacitor C of each pixel 14 in the super-pixel 10 are automatically averaged with each other. That is, in the second reading phase PH3, the second selection switch Q7 is turned on, and the average value of the P2 terminal of the capacitor C of each pixel 14 in the super pixel 10 is pushed to the signal reading circuit 20 through the second output switch Q6 as a source follower, so that the controller 30 can drive the signal reading circuit 20 to read the average output voltage Vout of all 4 photo sensing elements 11 in the super pixel 10, as shown in the above formula (1).
In the step (e), the average sensing voltage Vout 'of the photo sensing elements 11 of the super-pixel 10 is calculated according to the average output voltage Vout and the third reference voltage VREF, and the average sensing voltage Vout' of the sensing pixel 10 is obtained by subtracting the reference voltage VREF from the obtained average output voltage Vout as shown in the above formula (2). Therefore, the signal reading circuit 20 of the present application only performs simple operation, accelerates the sensing speed, does not occupy too much operation resources, and can reduce the number of transmission lines and the hardware area.
Referring to fig. 6, a third embodiment of the image sensor of the present application is substantially the same as the first embodiment shown in fig. 2, but each sub-driving unit 12b of the image sensor 1b includes an amplifier OP, a feedback capacitor CNT, and a reset switch Q1. The input end of the amplifier OP is connected to the negative end of the corresponding photo sensing element 11, and the output end thereof is connected to the first end P1 of the capacitor C; wherein the positive terminal of the photo-sensing component 11 is connected to ground voltage. The feedback capacitor CNT is connected across the input terminal and the output terminal of the amplifier OP. The reset switch Q1 is connected in parallel to the feedback capacitor CNT, and the gate of the reset switch Q1 is connected to a reset control signal RST. The controller 30b generates a reset control signal RST, a first control signal REF, and a second selection control signal SEL to each of the sub driving units 12b and the main driving unit 13.
Referring to fig. 7, the controller 30b controls the super pixel 10 shown in fig. 6 according to the timing chart shown in the figure, and the step of controlling the super pixel 10 and the signal reading circuit 20 by the controller 30b includes: (a) entering an initial phase PH 1; (b) ending the initial phase PH1, and entering an exposure phase Texp; (c) after the exposure phase Texp is over, entering a first reading phase PH 2; (d) after the first reading phase PH2 ends, enter a second reading phase PH 3; and (e) calculating an average sense voltage.
In the initial stage PH1, the controller 30b controls the reset switch Q1 of each sub-driving unit 12b and the first switch Q5 of the main driving unit 13 to be turned on to reset the photo sensing device 11 and the capacitor C, such that the voltage at the end P1 of the capacitor C close to the photo sensing device 11 is reset to a reset voltage VRST, and the voltage at the end P2 of the capacitor C close to the photo sensing device 11 is reset to a third reference voltage VREF. Next, in the step (b), in the exposure stage Texp, the photo sensing device 11 performs exposure to sense the image intensity, that is, the photo sensing device 11 converts the intensity of the external light into a corresponding voltage.
In the step (C), in the first reading phase PH2, the voltage of the photo sensing element 11 is instantaneously converted into charges by the feedback capacitor CNT and accumulated at the P1 end of the capacitor C, so that the voltage at the P1 end of the capacitor C becomes the sensing voltage VSIG to reflect the sensing voltage of the corresponding photo sensing element 11, and since a voltage difference (sensing voltage VSIG — reset voltage VRST) is instantaneously generated at the P1 end of the capacitor C, the voltage difference is reflected on the existing third reference voltage VREF at the P2 end of the capacitor C to form VREF + (VSIG-VRST). Since the P2 terminals of the capacitor C of each pixel 14 in the super-pixel 10 are connected to each other, the P2 terminals of the capacitor C of each pixel 14 in the super-pixel 10 are automatically averaged with each other. That is, in the first reading phase PH2, the selection switch Q7 is turned on, and the average value of the P2 terminal of the capacitor C of each pixel 14 in the super pixel 10 is pushed to the signal reading circuit 20 through the output switch Q6 as a source follower, so that the controller 30 can drive the signal reading circuit 20 to read the average output voltage Vout of all 4 photo sensing devices 11 in the super pixel 10, as shown in the above formula (1).
In the step (d), in the second reading phase PH3, the controller 30b controls the first switch Q5 of the main driving unit 13 to be turned on again to reset the P2 terminal of the capacitor C to the third reference voltage VREF; the controller 30b also controls the selection switch Q7 to be turned on and drives the signal reading circuit 20 to read the reference voltage VREF.
In the step (e), the average sensing voltage Vout 'of the photo sensing device 11 of the super-pixel 10 is calculated according to the average output voltage Vout and the third reference voltage VREF, and the average sensing voltage Vout' of the sensing pixel is obtained by subtracting the reference voltage VREF from the obtained average output voltage Vout, as shown in the above formula (2). Therefore, the signal reading circuit 202 of the present application only performs simple operation, accelerates the sensing speed, does not occupy excessive operation resources, and can reduce the number of transmission lines and the hardware area.
As can be seen from the first and third embodiments, the sensing method of the image sensor of the present application includes:
(a) resetting the photosensitive element and the capacitor in each pixel in the super pixel;
(b) sensing the light sensing component in each pixel;
(c) outputting the sensing voltage of the light sensing component in each pixel to a capacitor, and reading the average output voltage of the light sensing component in each pixel;
(d) resetting the capacitor in each pixel and reading out a third reference voltage; and
(e) and calculating an average sensing voltage according to the average output voltage of the light sensing component in each pixel and the third reference voltage.
In view of the above, the sensing method of the image sensor of the present application includes:
(a) resetting the light sensing component in each pixel in the super pixel;
(b) sensing the light sensing component in each pixel;
(c) reading a third reference voltage during the sensing period;
(d) after the sensing is finished, outputting the sensing voltage of the light sensing component in each pixel to a capacitor, and reading the average output voltage of the light sensing component in each pixel; and (e) calculating an average sensing voltage according to the average output voltage of the photo sensing element in each pixel and a third reference voltage.
In summary, a capacitor is connected between the main driving unit and all the sub-driving units in the super-pixel, so that the photo sensing elements and the capacitors can be reset first, and then the voltage value sensed by each photo sensing element can be read, as can be seen from the above formula (2), the voltage value is closer to the actual average output voltage; in addition, the average output voltage directly read by the signal reading circuit does not need to be subjected to complex operation, and the signal reading circuit is also beneficial to reducing the number of the transmission lines and reducing the layout area of the transmission lines.
The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (27)
1. An image sensor, comprising:
a super-pixel comprising:
a plurality of pixels, wherein each of the pixels comprises:
a light sensing component;
the sub-driving units are respectively connected to the light sensing assemblies so as to drive the light sensing assemblies; and
a capacitor having a first end and a second end;
wherein the second ends of the capacitors of the plurality of pixels are connected to each other such that the capacitance values of the capacitors of the plurality of pixels are automatically averaged with each other; and
the main driving unit is connected to the sub-driving units of the pixels through the capacitors of the pixels so as to simultaneously read sensing signals after the sub-driving units drive the light sensing assemblies; and
and the signal reading circuit is connected to the main driving unit of the super pixel so as to read the average sensing voltage of the light sensing components of the plurality of pixels.
2. The image sensor as in claim 1, wherein the main driving unit is respectively connected to the sub-driving units of the plurality of pixels through capacitances of the plurality of pixels.
3. The image sensor of claim 2, wherein the sub-driving unit of each of the pixels comprises:
the first reset switch is connected between a first reference voltage and the negative end of the corresponding optical sensing assembly in series, and the gate of the first reset switch is connected with a reset control signal; wherein the positive terminal of the light sensing component is connected to a ground voltage;
a first output switch, the gate of which is connected to the negative terminal of the photo sensing component;
a first selection switch having a gate connected to the first selection control signal; and
a second reset switch having a gate connected to the bias control signal;
wherein the first output switch, the first selection switch and the second reset switch are sequentially connected in series between a second reference voltage and a ground voltage.
4. The image sensor of claim 2, wherein the sub-driving unit of each of the pixels comprises:
a first reset switch, the gate of which is connected to the reset control signal;
a transmission switch having a gate connected to a transmission control signal, wherein the first reset switch and the transmission switch are sequentially connected in series between a first reference voltage and a negative terminal of the photo sensing device, and a positive terminal of the photo sensing device is connected to a ground voltage;
a first output switch, the gate of which is connected to the negative terminal of the photo sensing component;
a first selection switch having a gate connected to the first selection control signal; and
a second reset switch having a gate connected to the bias control signal;
wherein the first output switch, the first selection switch and the second reset switch are sequentially connected in series between a second reference voltage and a ground voltage.
5. The image sensor of claim 2, wherein the sub-driving unit of each of the pixels comprises:
an amplifier, the input end of which is connected to the negative end of the corresponding light sensing component, and the output end of which is connected to the first end of the capacitor; wherein the positive terminal of the light sensing component is connected to a ground voltage;
the feedback capacitor is bridged at the input end and the output end of the amplifier; and
and the reset switch is connected in parallel with the feedback capacitor, and the gate of the reset switch is connected to a reset control signal.
6. The image sensor of claim 3, wherein the main driving unit comprises:
the first switch is connected between a third reference voltage and each pixel, and the gate of the first switch is connected to a first control signal;
a second output switch, the gate of which is connected to the sub-driving unit of each pixel through the capacitance of each pixel; and
a second selection switch, the gate of which is connected to the second selection control signal;
wherein the second output switch and the second selection switch are sequentially connected in series between the second reference voltage and the signal reading circuit.
7. The image sensor of claim 6, wherein the first switch, the second output switch, and the second select switch are NMOS transistors.
8. The image sensor of claim 6, further comprising a controller that generates the reset control signal, the first selection control signal, the bias control signal, the first control signal, and the second selection control signal to the sub driving unit and the main driving unit of each of the pixels.
9. The image sensor of claim 8, wherein the controller is to:
in an initial stage, controlling the first reset switch, the first selection switch and the second reset switch of the sub-driving unit of each pixel and the first switch of the main driving unit to be conducted so as to reset the optical sensing component and the capacitor of each pixel;
and entering an exposure stage after the initial stage is finished, and controlling the light sensing component of each pixel to start sensing.
10. The image sensor of claim 9, wherein the controller is further configured to:
entering a first reading stage after the exposure stage is finished, controlling the conduction of a first selection switch of a sub-driving unit of each pixel to enable the voltage of the optical sensing component of each pixel to be output to the capacitor through a first output switch, controlling the conduction of a second selection switch of the main driving unit, and outputting the average voltage of the capacitor of each pixel to the signal reading circuit;
entering a second reading stage after the first reading stage is finished, controlling the first switch of the main driving unit to be conducted again to reset the capacitance of each pixel, and controlling the second selection switch of the main driving unit to be conducted and driving the signal reading circuit to read the third reference voltage; and
and calculating the average sensing voltage of the light sensing component of each pixel of the super-pixel according to the average voltage and the third reference voltage.
11. The image sensor of claim 4, wherein the main driving unit comprises:
the first switch is connected between a third reference voltage and each pixel, and the gate of the first switch is connected to a first control signal;
a second output switch, the gate of which is connected to the sub-driving unit of each pixel through the capacitance of each pixel; and
a second selection switch, the gate of which is connected to the second selection control signal;
wherein the second output switch and the second selection switch are sequentially connected in series between the second reference voltage and the signal reading circuit.
12. The image sensor of claim 11 wherein the first switch, the second output switch, and the second select switch are NMOS type transistors.
13. The image sensor of claim 11, further comprising a controller that generates the reset control signal, the transfer control signal, the first selection control signal, the bias control signal, the first control signal, and the second selection control signal to the sub driving unit and the main driving unit of each of the pixels.
14. The image sensor of claim 13, wherein the controller is to:
in a reset stage, controlling the first reset switch and the transmission switch of the sub-driving unit of each pixel to be conducted so as to reset the optical sensing component of each pixel;
and entering an exposure stage after the resetting stage is finished, and controlling the light sensing component of each pixel to start sensing.
15. The image sensor of claim 14, wherein the controller is further configured to:
entering a first read phase during the exposure phase: in the first reading stage, controlling the first reset switch, the first selection switch and the second reset switch of the sub-driving unit of each pixel to be conducted with the first switch of the main driving unit so as to reset the capacitance of each pixel; simultaneously controlling a second selection switch of the main driving unit to be conducted and driving the signal reading circuit to read a third reference voltage;
after the exposure stage and the first reading stage are finished, entering a second reading stage, controlling the conduction of a transmission switch and a first selection switch of a sub-driving unit of each pixel, and enabling the voltage of the light sensing component of each pixel to be output to a capacitor through the transmission switch and a first output switch; meanwhile, a second selection switch of the main driving unit is controlled to be conducted, and the average voltage of the capacitor of each pixel is output to the signal reading circuit; and
and calculating the average sensing voltage of the light sensing components of all the pixels of the super pixel according to the average voltage and the third reference voltage.
16. The image sensor of claim 5, wherein the main driving unit comprises:
the first switch is connected between a third reference voltage and each pixel, and the gate of the first switch is connected to a first control signal;
a second output switch, the gate of which is connected to the sub-driving unit of each pixel through the capacitance of each pixel; and
a second selection switch, the gate of which is connected to the second selection control signal;
wherein the second output switch and the second selection switch are sequentially connected in series between a second reference voltage and the signal reading circuit.
17. The image sensor of claim 16 wherein the first switch, the second output switch, and the second select switch are NMOS type transistors.
18. The image sensor of claim 17, further comprising a controller that generates the reset control signal, the first control signal, and the second selection control signal to the sub driving unit and the main driving unit of each of the pixels.
19. The image sensor of claim 18, wherein the controller is to:
in an initial stage, controlling the reset switch of the sub-driving unit of each pixel and the first switch of the main driving unit to be conducted so as to reset the optical sensing component and the capacitor of each pixel;
and entering an exposure stage after the initial stage is finished, and controlling the light sensing component of each pixel to start sensing.
20. The image sensor of claim 19, wherein the controller is further configured to:
entering a first reading stage after the exposure stage is finished, controlling the voltage of the light sensing assembly of each pixel to be output to a capacitor, controlling a selection switch of the main driving unit to be switched on, and outputting the average voltage of the capacitor of each pixel to the signal reading circuit;
entering a second reading stage after the first reading stage is finished, controlling a first switch of the main driving unit to be conducted to reset the capacitance of each pixel, and controlling a selection switch of the main driving unit to be conducted and driving the signal reading circuit to read the reference voltage; and
and calculating the average sensing voltage of the light sensing component of each pixel of the super-pixel according to the average voltage and the reference voltage.
21. The image sensor of any of claims 1 to 20, wherein the light sensing element is a photodiode.
22. A sensing method of an image sensor, wherein the image sensor is the image sensor of claim 1, the sensing method comprising:
(a) resetting the light sensing component and the capacitor of each pixel;
(b) sensing the light sensing component in each pixel;
(c) outputting the voltage of the light sensing component in each pixel to a capacitor, and reading the average voltage of the capacitor in each pixel;
(d) resetting the capacitor in each pixel and reading out a reset voltage; and
(e) and calculating the average sensing voltage of the light sensing component in each pixel according to the average voltage and the reset voltage.
23. The method of claim 22, in step (e), comprising:
subtracting a reset voltage from the average voltage to obtain the average sensing voltage.
24. The method according to claim 22 or 23, wherein the photo sensing element in each pixel is a photodiode.
25. A sensing method of an image sensor, wherein the image sensor is the image sensor of claim 1, the sensing method comprising:
(a) resetting the light sensing component of each pixel;
(b) sensing the light sensing component in each pixel;
(c) reading out a reset voltage during a sensing period;
(d) after the sensing is finished, outputting the voltage of the light sensing component in each pixel to a capacitor, and reading the average voltage of the capacitor in each pixel; and
(e) and calculating the average sensing voltage of the light sensing component in each pixel according to the average voltage and the reset voltage.
26. The method of claim 25, in step (e), comprising:
subtracting a reset voltage from the average voltage to obtain the average sensing voltage.
27. The method according to claim 25 or 26, wherein the photo sensing element in each pixel is a photodiode.
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| KR20140047494A (en) * | 2012-10-12 | 2014-04-22 | 삼성전자주식회사 | Subpixel, image sensor having the same and image sensing system |
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| CN1467699A (en) * | 2002-06-21 | 2004-01-14 | 奇景光电股份有限公司 | Method and related apparatus for driving an lcd monitor |
| CN102510450A (en) * | 2011-10-17 | 2012-06-20 | 北京瑞澜联合通信技术有限公司 | Image sensor, pick-up device and image data generation method |
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