Image sensor, control method thereof and computer readable storage medium

Abstract

The invention provides an image sensor, a control method of the image sensor and a readable storage medium, and the image sensor comprises a photoelectric conversion circuit which comprises a first transmission transistor; the signal output circuit comprises a floating diffusion node, a first overflow circuit and a second overflow circuit, one end of the first overflow circuit is connected with the floating diffusion node, and the other end of the first overflow circuit is connected with one end of the second overflow circuit; and the controller is used for controlling the first transmission transistor, the first overflow circuit and the second overflow circuit to be switched on and enabling the photoelectric conversion circuit, the floating diffusion node, the first overflow circuit and the second overflow circuit to form an overflow path when the barrier heights of the first transmission transistor, the first overflow circuit and the second overflow circuit meet set conditions. According to the embodiment of the invention, the high-intensity light detection range of the pixel structure in the image sensor is improved, so that the dynamic range is effectively improved, and flicker suppression is realized.

Description

Technical Field

[0001] The present invention relates to the field of image processing technology, and in particular to an image sensor, a control method thereof, and a computer-readable storage medium. Background Art

[0002] In the related technologies, the diversity of vehicle driving environments puts forward extremely high technical requirements for CIS (Camera Image Sensor), especially in terms of high dynamic range and LED (Light Emitting Diode) flicker suppression. The current technology still faces some challenges and is unable to improve the dynamic range and suppress LED flicker. Summary of the invention

[0003] The present invention aims to solve at least one of the technical problems existing in the prior art.

[0004] To this end, an object of the present invention is to provide an image sensor that improves the charge accommodation range while increasing the detection range of high-intensity light by a pixel structure in the image sensor, thereby effectively improving the dynamic range and achieving flicker suppression.

[0005] Therefore, a second objective of the present invention is to provide a control method for an image sensor.

[0006] To this end, a third object of the present invention is to provide a non-transitory computer-readable storage medium.

[0007] In order to achieve the above-mentioned purpose, an embodiment of the first aspect of the present invention proposes an image sensor, comprising: a photoelectric conversion circuit, the photoelectric conversion circuit comprising a first photoelectric conversion sub-circuit; a signal output circuit, the signal output circuit comprising a floating diffusion node, a first overflow circuit and a second overflow circuit, one end of the first overflow circuit is connected to the floating diffusion node, and the other end of the first overflow circuit is connected to one end of the second overflow circuit; a controller, used to control the first photoelectric conversion sub-circuit, the first overflow circuit and the second overflow circuit to be turned on and when the barrier heights of the first photoelectric conversion sub-circuit, the first overflow circuit and the second overflow circuit meet the set conditions, the first photoelectric conversion sub-circuit, the floating diffusion node, the first overflow circuit and the second overflow circuit form an overflow path.

[0008] According to the image sensor of the embodiment of the present invention, by controlling the first photoelectric conversion sub-circuit, the first overflow circuit and the second overflow circuit to be turned on and when the barrier height of the first photoelectric conversion sub-circuit and the barrier height of the first overflow circuit and the second overflow circuit meet preset conditions, the charge in the first photoelectric conversion sub-circuit can be transmitted to the first overflow circuit and the second overflow circuit to form an overflow path composed of the first photoelectric conversion sub-circuit, the floating diffusion node, the first overflow circuit and the second overflow circuit, and the excess charge after the first photoelectric conversion sub-circuit is fully loaded is transmitted through the overflow path to form an overflow path that can accommodate the excess charge, while improving the charge accommodation range, the detection range of the pixel structure in the image sensor to high-intensity light is improved, thereby effectively achieving dynamic range and flicker suppression.

[0009] In addition, the image sensor according to the above embodiment of the present invention may also have the following additional technical features:

[0010] In some embodiments, the first photoelectric conversion sub-circuit includes: a first photodiode, the anode of the first photodiode is grounded; a first transfer transistor, the source of the first transfer transistor is connected to the cathode of the first photodiode, and the drain of the first transfer transistor is connected to the floating diffusion node, for turning on or off the overflow path between the first photodiode and the floating diffusion node.

[0011] In some embodiments, the barrier heights of the first photoelectric conversion sub-circuit, the first overflow circuit and the second overflow circuit meet set conditions, including: the barrier height of the first photoelectric conversion sub-circuit is higher than the barrier height of the first overflow circuit and the barrier height of the first overflow circuit is higher than the barrier height of the second overflow circuit.

[0012] In some embodiments, the photoelectric conversion circuit further includes: a second photoelectric conversion sub-circuit.

[0013] In some embodiments, the second photoelectric conversion subcircuit includes: a second photodiode, the anode of the second photodiode is grounded; a second transfer transistor, the source of the second transfer transistor is connected to the cathode of the second photodiode, and the drain of the second transfer transistor is connected to the floating diffusion node.

[0014] In some embodiments, when controlling the first photoelectric conversion sub-circuit, the first overflow circuit, and the second overflow circuit to be turned on, the controller is further used to: control the second transfer transistor to be turned off.

[0015] In some embodiments, the first overflow circuit includes: a dual conversion gain control transistor, a source of the dual conversion gain control transistor is connected to the floating diffusion node; and a first overflow capacitor, one end of the first overflow capacitor is connected to the drain of the dual conversion gain control transistor.

[0016] In some embodiments, the second overflow circuit includes: three conversion gain control transistors, the sources of the three conversion gain control transistors are connected to the other end of the first overflow capacitor; and a second overflow capacitor, one end of the second overflow capacitor is connected to the drain terminal of the three conversion gain control transistors.

[0017] In some embodiments, after controlling the first photoelectric conversion sub-circuit, the first overflow circuit and the second overflow circuit to be turned on, the controller is also used to: control the three conversion gain control transistors and the first transmission transistor to be turned off, and after the three conversion gain control transistors and the first transmission transistor are turned off, control the dual conversion gain control transistor to be turned on, so as to obtain a first reset signal of the photoelectric conversion circuit under medium conversion gain.

[0018] In some embodiments, after obtaining the first reset signal of the photoelectric conversion circuit at a medium conversion gain, the controller is further used to: control the dual conversion gain control transistor to turn off to obtain the first reset signal of the photoelectric conversion circuit at a high conversion gain.

[0019] In some embodiments, after obtaining the first reset signal of the photoelectric conversion circuit under high conversion gain, the controller is also used to: control the first transfer transistor to be turned on, so as to control the first transfer transistor to be turned off when the charge in the first photodiode is transferred to the floating diffusion node, so as to obtain the first valid signal of the photoelectric conversion circuit under high conversion gain.

[0020] In some embodiments, after obtaining the first valid signal of the photoelectric conversion circuit under high conversion gain, the controller is also used to: control the dual conversion gain control transistor and the first transfer transistor to be turned on, so as to control the first transfer transistor to be turned off when the charge of the first photodiode is transferred to the floating diffusion node and the first overflow circuit, so as to obtain the first valid signal of the photoelectric conversion circuit under medium conversion gain.

[0021] In some embodiments, after obtaining the first valid signal of the photoelectric conversion circuit under medium conversion gain, the controller is also used to: control the three conversion gain control transistors and the first transfer transistor to be turned on, so as to control the first transfer transistor to be turned off when the charge of the first photodiode is transferred to the floating diffusion node, the first overflow circuit and the second overflow circuit, so as to obtain the first valid signal of the photoelectric conversion circuit under low conversion gain.

[0022] In some embodiments, the signal output circuit further includes: a reset transistor, a source of the reset transistor is connected to one end of the second overflow circuit, and a drain of the reset transistor is connected to a power supply voltage.

[0023] In some embodiments, after obtaining the first valid signal of the photoelectric conversion circuit under low conversion gain, the controller is also used to: control the reset transistor to be turned on, so as to control the reset transistor to be turned off when the floating diffusion node, the first overflow capacitor and the second overflow capacitor are reset, so as to obtain the first reset signal of the photoelectric conversion circuit under low conversion gain.

[0024] In some embodiments, after obtaining a first reset signal of the photoelectric conversion circuit at a low conversion gain, the controller is further used to: control the dual conversion gain control transistor to be turned on to obtain a second reset signal of the photoelectric conversion circuit at a medium conversion gain.

[0025] In some embodiments, after obtaining the second reset signal of the photoelectric conversion circuit at a medium conversion gain, the controller is further used to: control the dual conversion gain control transistor to turn off to obtain the second reset signal of the photoelectric conversion circuit at a high conversion gain.

[0026] In some embodiments, after obtaining a second reset signal of the photoelectric conversion circuit at a high conversion gain, the controller is also used to: control the second transfer transistor to be turned on, so as to control the second transfer transistor to be turned off when the charge in the second photodiode is transferred to the floating diffusion node, so as to obtain a second effective signal of the photoelectric conversion circuit at a high conversion gain.

[0027] In some embodiments, after obtaining a second effective signal of the photoelectric conversion circuit at a high conversion gain, the controller is also used to: control the dual conversion gain control transistor and the second transfer transistor to be turned on, so as to control the second transfer transistor to be turned off when the charge in the second photodiode is transferred to the floating diffusion node and the first overflow capacitor, so as to obtain a second effective signal of the first photoelectric conversion circuit at a medium conversion gain.

[0028] In some embodiments, the signal output circuit also includes: an amplifying transistor, the drain of which is connected to the power supply voltage, and the gate of which is connected to the floating diffusion node; a row selecting transistor, the source of which is connected to the source of the amplifying transistor, and the drain of which is connected to the signal reading circuit.

[0029] In some embodiments, when controlling the first photoelectric conversion sub-circuit, the first overflow circuit and the second overflow circuit to be turned on, the controller is specifically used to: control the photoelectric conversion sub-circuit, the first overflow circuit and the second overflow circuit to be turned on to a preset opening.

[0030] A second aspect of the present invention provides a control method for an image sensor, which is used for the image sensor described in the above embodiment of the present invention. The image sensor includes a photoelectric conversion circuit, a signal output circuit and a controller. The signal output circuit includes a floating diffusion node, a first overflow circuit and a second overflow circuit. The photoelectric conversion circuit includes a first photoelectric conversion sub-circuit. The control method includes: controlling the first photoelectric conversion sub-circuit, the first overflow circuit and the second overflow circuit to be turned on and when the barrier heights of the first photoelectric conversion sub-circuit, the first overflow circuit and the second overflow circuit meet the set conditions, the photoelectric conversion circuit, the floating diffusion node, the first overflow circuit and the second overflow circuit form an overflow path.

[0031] According to the control method of the image sensor of the embodiment of the present invention, by controlling the first photoelectric conversion sub-circuit, the first overflow circuit and the second overflow circuit to be turned on and when the barrier height of the first photoelectric conversion sub-circuit and the barrier height of the first overflow circuit and the second overflow circuit meet the preset conditions, the charge in the first photoelectric conversion sub-circuit can be transmitted to the first overflow circuit and the second overflow circuit to form an overflow path composed of the first photoelectric conversion sub-circuit, the floating diffusion node, the first overflow circuit and the second overflow circuit, and the excess charge after the first photoelectric conversion sub-circuit is fully loaded is transmitted through the overflow path to form an overflow path that can accommodate the excess charge, while improving the charge accommodation range, the detection range of the pixel structure in the image sensor to high-intensity light is improved, thereby effectively improving the dynamic range and flicker suppression.

[0032] A third aspect of the present invention provides a non-temporary computer-readable storage medium on which a control program for an image sensor is stored. When the control program for the image sensor is executed by a processor, the control method for the image sensor described in the above embodiment of the present invention is implemented.

[0033] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] The above and / or additional aspects and advantages of the present invention will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0035] Figure 1is a schematic diagram of a pixel structure in an image sensor according to the related art;

[0036] Figure 2 is a schematic diagram of a data reading method in an image sensor according to the related art;

[0037] Figure 3 is a circuit diagram of an image sensor according to the related art;

[0038] Figure 4 is a circuit diagram of an image sensor according to an embodiment of the present invention;

[0039] Figure 5 4 is a circuit timing diagram of an image sensor according to an embodiment of the present invention.

[0040] Reference numerals:

[0041] Image sensor 10;

[0042] Photoelectric conversion circuit 11; first photoelectric conversion sub-circuit 110;

[0043] Signal output circuit 12; first overflow circuit 121; second overflow circuit 122. DETAILED DESCRIPTION

[0044] Embodiments of the present invention are described in detail below. The embodiments described with reference to the accompanying drawings are exemplary. Embodiments of the present invention are described in detail below.

[0045] In related technologies, when a vehicle is driving, the ambient light changes greatly, and the dynamic range of the vehicle CIS needs to exceed 120dB, usually between 120dB-140dB. For example, when a vehicle drives from a dark basement to the outdoors facing the strong sunlight, or perceives pedestrians under the shade of trees under the headlights of oncoming vehicles at night, the CIS needs to be able to capture images clearly, so that the CIS has a high dynamic range to cope with such extreme light changes. In addition, since the flashing frequency of LED signs and traffic lights may not be synchronized with the sampling frequency of the CIS, flickering or distortion may occur in the image, which interferes with the machine vision system and affects driving safety.

[0046] In view of the above problems, current technologies have also proposed corresponding solutions, such as Figure 1As shown in the figure, it is a schematic diagram of the pixel structure in the image sensor, where different colors represent different CFs (Color Filters). The scheme adopts a 4cell structure, that is, the pixel structure consists of four sub-pixels, three of which are used as LPDs (Large Photodetectors), and the other sub-pixel is used as an SPD (Small Photodetector) by combining a light absorption attenuation film and other methods to reduce the pixel light absorption sensitivity. In general, the optical absorption attenuation ratio of LPD to SPD is 1:10+.

[0047] like Figure 2 As shown in the figure, it is a schematic diagram of the data reading method in the image sensor. LPD performs two exposures within one exposure time of SPD, one long exposure and one short exposure, which are realized by splicing long and short exposures. Among them, the long exposure of 1stLPD (first LPD) is mainly used to obtain darker signals, and the long exposure of 2nd LPD (second LPD) is mainly used to obtain strong light signals; the long exposure of 3rd SPD (third SPD) and the short exposure of 4th LPD (fourth LPD) are mainly used to obtain medium light intensity signals, which mainly depends on the time ratio of long and short exposure of LPD and the optical sensitivity ratio of LPD / SPD. Taking the competitive company as an example, the sensitivity ratio of SPD to LPD is usually about 1:10+, and the time ratio of long and short exposure of LPD is about 1:50+.

[0048] Specifically, the circuit diagram of the image sensor is as follows: Figure 3 As shown, the LPD performs long exposure to obtain darker signals; the SPD performs long exposure to obtain medium-intensity light signals; and the LPD performs short exposure to obtain ultra-strong light signals. The LPD / SPD sensitivity ratio (sensitivity ratio of long exposure / short exposure) is combined with the exp time ratio (experience time ratio) to form a high dynamic range performance, while also ensuring that the SNR (Signal to Noise Ratio) is not too low. In terms of timing design, the LPD performs two exposures within one exposure time of the SPD, so that the SPD does not have an overflow function during the exposure period. At the same time, the timing operation is complex, and the LFM (Linear Frequency Modulation) coverage range of the timing does not fully cover the entire dynamic range.

[0049] Based on the above, the embodiment of the present invention forms an overflow path by controlling the on or off state of the first optoelectronic circuit, the first overflow circuit, and the second overflow circuit, thereby expanding the detection range for high-intensity light and achieving the purpose of improving the dynamic range. In addition, only one exposure is required to achieve a high dynamic range and LED flicker suppression, which is simpler to operate than the long and short exposure splicing of competitors, so that the SPD has an overflow function during exposure, and LED flicker suppression can also achieve full dynamic range coverage.

[0050] Reference below Figure 4 and Figure 5 An image sensor according to an embodiment of the present invention is described.

[0051] Figure 4 is a circuit diagram of an image sensor according to an embodiment of the present invention. Figure 4 As shown, the image sensor 10 includes: a photoelectric conversion circuit 11, a signal output circuit 12 and a controller (not shown in the figure).

[0052] Among them, the photoelectric conversion circuit 11 includes a first photoelectric conversion sub-circuit 110; the signal output circuit 12 includes a floating diffusion node FD1, a first overflow circuit 121 and a second overflow circuit 122, one end of the first overflow circuit 121 is connected to the floating diffusion node FD1, and the other end of the first overflow circuit 121 is connected to one end of the second overflow circuit 122; the controller is used to control the first photoelectric conversion sub-circuit 110, the first overflow circuit 121 and the second overflow circuit 122 to be turned on, for example, to control the above circuits to be turned on to a preset opening, that is, not completely turned off, and when the barrier heights of the first photoelectric conversion sub-circuit 110, the first overflow circuit 121 and the second overflow circuit 122 meet the set conditions, the first photoelectric conversion sub-circuit 110, the floating diffusion node FD1, the first overflow circuit 121 and the second overflow circuit 122 form an overflow path.

[0053] In the embodiment, the photoelectric conversion circuit 11 and the signal output circuit 12 are circuit components of a pixel structure, and the on or off state of the first photoelectric conversion sub-circuit 110, the first overflow circuit 121 and the second overflow circuit 122 in the pixel structure are controlled based on the timing of the controller, so that the pixel circuit forms an overflow path composed of the first photoelectric conversion sub-circuit 110, the floating diffusion node FD1, the first overflow circuit 121 and the second overflow circuit 122, so that after the charge in the photoelectric conversion circuit 11 is fully loaded, the excess charge is accommodated through the overflow path, thereby improving the ability of the pixel circuit to accommodate charge, increasing the detection range of the pixel circuit for high-intensity light, and achieving the purpose of improving the dynamic range.

[0054] For example, at a first set timing, such as T0, the controller controls the first photoelectric conversion subcircuit 110, the first overflow circuit 121, and the second overflow circuit 122 to be turned off to a preset opening, that is, not completely turned off, and determines that the barrier heights of the first photoelectric conversion subcircuit 110, the first overflow circuit 121, and the second overflow circuit 122 meet a preset condition, that is, the barrier height of the first photoelectric conversion subcircuit 110 is higher than the barrier height of the first overflow circuit 121, and the barrier height of the first overflow circuit 121 is higher than the second overflow circuit 1 22, the excess charge flows to the overflow path according to the potential barrier height. It can be understood that a path can be formed by controlling the conduction or disconnection of the first photoelectric conversion sub-circuit 110, the first overflow circuit 121 and the second overflow circuit 122. However, on the basis of forming the path, the potential barrier heights of the first photoelectric conversion sub-circuit 110, the first overflow circuit 121 and the second overflow circuit 122 need to meet the above-mentioned set conditions, and the excess charge will be transferred to the overflow path, thereby achieving the purpose of improving the dynamic range.

[0055] Specifically, the photoelectric conversion circuit 11 is used to convert optical signals into electrical signals, and the floating diffusion node FD1 is used to store charges. When the photoelectric conversion circuit 11 is fully loaded and there is excess charge, the excess charge is transferred to the overflow path to increase the load capacity.

[0056] Thus, the above-mentioned image sensor 10 controls the first photoelectric conversion sub-circuit 110, the first overflow circuit 121 and the second overflow circuit 122 to be turned off to a preset opening and when the barrier height of the first photoelectric conversion sub-circuit 110 and the barrier height of the first overflow circuit 121 and the second overflow circuit 122 meet the preset conditions, the charge in the first photoelectric conversion sub-circuit 110 can be transmitted to the first overflow circuit 121 and the second overflow circuit 122 to form an overflow path composed of the first photoelectric conversion sub-circuit 110, the floating diffusion node FD1, the first overflow circuit 121 and the second overflow circuit 122, and the excess charge after the first photoelectric conversion sub-circuit 110 is fully loaded is transmitted through the overflow path to form an overflow path that can accommodate the excess charge. While improving the charge accommodation range, the detection range of the pixel structure in the image sensor 10 to high-intensity light is improved, thereby effectively improving the dynamic range and flicker suppression.

[0057] In some embodiments, Figure 4 As shown, the first photoelectric conversion sub-circuit 110 includes: a first photodiode PD4 and a first transfer transistor TX4, the anode of the first photodiode PD4 is grounded; the source of the first transfer transistor TX4 is connected to the cathode of the first photodiode PD4, and the drain of the first transfer transistor TX4 is connected to the floating diffusion node FD1, which is used to turn on or off the overflow path between the first photodiode PD4 and the floating diffusion node FD1.

[0058] In the embodiment, the on or off state of the first transfer transistor TX4 is controlled to be on when the first photodiode PD4 is fully loaded with charges, so that the charges can be transferred to the floating diffusion node FD1 and the overflow circuit through the first transfer transistor TX4.

[0059] In one embodiment of the present invention, Figure 4 As shown, the barrier heights of the first photoelectric conversion sub-circuit 110, the first overflow circuit 121 and the second overflow circuit 122 meet the set conditions, including: the barrier height of the first photoelectric conversion sub-circuit 110 is higher than the barrier height of the first overflow circuit 121 and the barrier height of the first overflow circuit 121 is higher than the barrier height of the second overflow circuit 122.

[0060] In an embodiment, Figure 4 As shown, in the process of forming an overflow path by the first photoelectric conversion subcircuit 110, the floating diffusion node FD1, the first overflow circuit 121, and the second overflow circuit 122, the barrier height of the first photoelectric conversion subcircuit 110 is higher than the barrier height of the first overflow circuit 121, and at the same time, the barrier height of the first overflow circuit 121 is higher than the barrier height of the second overflow circuit 122, that is, during the transmission process, the charge passes through the first photoelectric conversion subcircuit 110, the first overflow circuit 121, and the second overflow circuit 122 in sequence. In addition, the barrier height is also related to the voltage. The higher the barrier height, the smaller the corresponding voltage. Conversely, the lower the barrier height, the larger the corresponding voltage. Therefore, the barrier heights of the first photoelectric conversion subcircuit 110, the first overflow circuit 121, and the second overflow circuit 122 satisfying the set conditions can also be understood as the voltage of the first photoelectric conversion subcircuit 110 is less than the voltage of the first overflow circuit 121 and the voltage of the first overflow circuit 121 is less than the voltage of the second overflow circuit 122, that is, Voff_TX4 <Voff_DCG<Voff_TCG。

[0061] By controlling the conduction states of the first photoelectric conversion sub-circuit 110, the first overflow charge 121 and the second overflow circuit 122, and at the same time making their potential barrier heights satisfy the above conditions, when the charge in the first photoelectric conversion sub-circuit 110 exceeds the load capacity and overflows, the charge will more easily move in the direction of a lower potential barrier. Therefore, the charge will flow in order from the first photoelectric conversion sub-circuit 110, the floating diffusion node FD1, the first overflow circuit 121 and the second overflow circuit 122 in order of the potential barrier height, thereby preventing excessive charge accumulation in one of the places.

[0062] In one embodiment of the present invention, Figure 4 As shown, the photoelectric conversion circuit 11 further includes: a second photoelectric conversion sub-circuit.

[0063] In an embodiment, the photoelectric conversion circuit 11 further includes a second photoelectric conversion sub-circuit. For example, the photoelectric conversion circuit 11 includes two second photoelectric conversion sub-circuits or three photoelectric conversion sub-circuits.

[0064] In one embodiment of the present invention, Figure 4 As shown, the second photoelectric conversion sub-circuit includes: a second photodiode and a second transfer transistor, the anode of the second photodiode is grounded; the source of the second transfer transistor is connected to the cathode of the second photodiode, and the drain of the second transfer transistor is connected to the floating diffusion node FD1.

[0065] In an embodiment, when there are three second photoelectric conversion sub-circuits, the second photodiodes may be PD1, PD2, and PD3, respectively, and the second transfer transistors correspondingly connected to the second photodiodes PD1, PD2, and PD3 may be TX1, TX2, and TX3, respectively. When the first photodiode PD4, the first overflow circuit 121, and the second overflow circuit 122 are controlled to be turned on to a preset opening, the second transfer transistors TX1, TX2, and TX3 in the second photoelectric conversion sub-circuit are turned off.

[0066] Specifically, Figure 4 As shown, the anode of the second photodiode is grounded, that is, the anodes of the second photodiodes PD1, PD2 and PD3 are all grounded, and the second photodiode can convert the optical signal into an electrical signal, so that when the second transfer transistor is turned on, the charge in the second photodiode is transferred to the floating diffusion node FD1.

[0067] In one embodiment of the present invention, Figure 4 and Figure 5 As shown, when controlling the first photoelectric conversion sub-circuit 110, the first overflow circuit 121 and the second overflow circuit 122 to be turned on, the controller is also used to: control the second transfer transistor to be turned off.

[0068] In an embodiment, the controller controls the on or off state of the first photoelectric conversion sub-circuit 110, the first overflow circuit 121, the second overflow circuit 122, and the second transfer transistors TX1, TX2, and TX3. For example, when the first photoelectric conversion sub-circuit 110, the first overflow circuit 121, and the second overflow circuit 122 are controlled to be turned on to a preset opening, the second transfer transistors TX1, TX2, and TX3 are controlled to be turned off to form an overflow path of the first photodiode PD4, the floating diffusion node FD1, the first overflow circuit 121, and the second overflow circuit 122.

[0069] like Figure 5As shown, corresponding to the moment T0, when the second transfer transistors TX1, TX2, and TX3 are turned off, the integration process of the first photodiode PD4 starts. At the moment T0, the first transfer transistor TX4, the first overflow circuit 121, and the second overflow circuit 122 are controlled to be turned on to a preset opening, that is, not fully turned on, so that the charge can overflow.

[0070] In one embodiment of the present invention, Figure 4 As shown, the first overflow circuit 121 includes: a dual conversion gain control transistor DCG and a first overflow capacitor FD2, the source of the dual conversion gain control transistor DCG is connected to the floating diffusion node FD1; one end of the first overflow capacitor FD2 is connected to the drain of the dual conversion gain control transistor DCG.

[0071] In an embodiment, Figure 4 As shown, the source of the dual conversion gain control transistor DCG is connected to the floating diffusion node FD1, and the drain of the dual conversion gain control transistor DCG is connected to one end of the first overflow capacitor FD2. By controlling the on or off state of the dual conversion gain control transistor DCG, the on or off state of the first overflow circuit 121 can be achieved.

[0072] Specifically, the on or off state of the dual conversion gain control transistor DCG can control the transfer of charges. For example, when the amount of charge in the first photodiode PD4 exceeds the load capacity, by controlling the dual conversion gain control transistor DCG to be turned on, the first overflow capacitor FD2 can store excess charge, thereby improving the detection range of the image sensor 10 for high-intensity light.

[0073] In one embodiment of the present invention, Figure 4 As shown, the second overflow circuit 122 includes: three conversion gain control transistors TCG and a second overflow capacitor FD3, the source of the three conversion gain control transistors TCG is connected to the other end of the first overflow capacitor FD2; one end of the second overflow capacitor FD3 is connected to the drain end of the three conversion gain control transistors TCG.

[0074] In an embodiment, Figure 4 As shown, the source of the three conversion gain control transistor TCG is connected to the other end of the first overflow capacitor FD2, and one end of the second overflow capacitor FD3 is connected to the drain end of the three conversion gain control transistor TCG. By controlling the three conversion gain control transistor TCG to be turned on, the charge can be transferred to the second overflow capacitor FD3.

[0075] Specifically, the second overflow capacitor FD3 has a larger capacitance. When the charge in the first photodiode PD4 reaches the load capacity, the first transfer transistor TX4, the dual conversion gain control transistor DCG and the triple conversion gain control transistor TCG are turned on to form an overflow path. The excess charge can pass through the first transfer transistor TX4, the floating diffusion node FD1, the first overflow capacitor FD2 and the second overflow capacitor FD3 in sequence, thereby further expanding the detection range of high-intensity light and achieving the mentioned dynamic range.

[0076] It can be understood that when the amount of charge in the first overflow capacitor FD2 reaches a preset overflow condition, by adjusting the three conversion gain control transistors TCG, the charge can be allowed to flow to the second overflow capacitor FD3. For example, by controlling the three conversion gain control transistors TCG to be turned on, the charge flows to the second overflow capacitor FD3, and the second overflow capacitor FD3 can store excess charge.

[0077] In one embodiment of the present invention, Figure 4 and Figure 5 As shown, after controlling the first photoelectric conversion sub-circuit 110, the first overflow circuit 121 and the second overflow circuit 122 to be turned on, the controller is also used to: control the three conversion gain control transistors TCG and the first transmission transistor TX4 to be turned off, and after the three conversion gain control transistors TCG and the first transmission transistor TX4 are turned off, control the dual conversion gain control transistor DCG to be turned on, so as to obtain the first reset signal of the photoelectric conversion circuit 11 under the medium conversion gain.

[0078] In the embodiment, the first photoelectric conversion subcircuit 110, the first overflow circuit 121 and the second overflow circuit 122 are controlled to be turned on to a preset opening and after the integration of the first photodiode PD4 is completed, the three conversion gain control transistors TCG and the first transmission transistor TX4 are controlled to be turned off, and at the end of the integration and overflow process, the dual conversion gain control transistor DCG is controlled to be turned on. Since the charge capacity of the second overflow capacitor FD3 is much larger than the charge capacity of the floating diffusion node FD1 and the first overflow capacitor FD2, when the three conversion gain control transistors TCG are turned off, most of the excess charge generated in the integration and overflow process will flow to the second overflow capacitor FD3, and the amount of charge remaining in the floating diffusion node FD1 and the first overflow capacitor FD2 is relatively small. And, this process corresponds to Figure 5 At the time T1 shown, at the time T1, the first reset signal SPD MCG_SHR of the photoelectric conversion circuit 11 at the medium conversion gain can be accurately read, thereby improving the accuracy of signal acquisition.

[0079] In one embodiment of the present invention, Figure 4 and Figure 5As shown, after obtaining the first reset signal of the photoelectric conversion circuit 11 under the medium conversion gain, the controller is also used to: control the dual conversion gain control transistor DCG to turn off to obtain the first reset signal of the photoelectric conversion circuit 11 under the high conversion gain.

[0080] In an embodiment, in combination Figure 4 and Figure 5 As shown, at time T2, after obtaining the first reset signal SPD MCG_SHR of the photoelectric conversion circuit 11 under medium conversion gain, the dual conversion gain control transistor DCG is controlled to be turned off, so that the first reset signal SPD HCG_SHR of the photoelectric conversion circuit 11 under high conversion gain can be accurately read.

[0081] In one embodiment of the present invention, Figure 4 and Figure 5 As shown, after obtaining the first reset signal of the photoelectric conversion circuit 11 under high conversion gain, the controller is also used to: control the first transfer transistor TX4 to be turned on, so as to control the first transfer transistor TX4 to be turned off when the charge in the first photodiode PD4 is transferred to the floating diffusion node FD1, so as to obtain the first valid signal of the photoelectric conversion circuit 11 under high conversion gain.

[0082] In an embodiment, in combination Figure 4 and Figure 5 As shown, at time T3, after obtaining the first reset signal SPD HCG_SHR of the photoelectric conversion circuit 11 under high conversion gain, the controller controls the first transfer transistor TX4 to be turned on, so that the charge in the first photodiode PD4 is transferred to the floating diffusion node FD1. After the charge transfer is completed, the controller controls the first transfer transistor TX4 to be turned off, thereby reading the first valid signal SPD HCG_SHS of the photoelectric conversion circuit 11 under high conversion gain.

[0083] In one embodiment of the present invention, Figure 4 and Figure 5 As shown, after obtaining the first effective signal of the photoelectric conversion circuit 11 under high conversion gain, the controller is also used to: control the dual conversion gain control transistor DCG and the first transfer transistor TX4 to be turned on, so as to control the first transfer transistor TX4 to be turned off when the charge of the first photodiode PD4 is transferred to the floating diffusion node FD1 and the first overflow circuit 121, so as to obtain the first effective signal of the photoelectric conversion circuit 11 under medium conversion gain.

[0084] In an embodiment, in combination Figure 4 and Figure 5As shown, at time T4, after obtaining the first valid signal SPD HCG_SHS of the photoelectric conversion circuit 11 under high conversion gain, the controller controls the dual conversion gain control transistor DCG and the first transfer transistor TX4 to be turned on at the same time. At this time, the charge in the first photodiode PD4 begins to be transferred, and the charge is transferred to the floating diffusion node FD1 and the first overflow circuit 121. When the charge transfer is completed, the controller controls the first transfer transistor TX4 to be turned off, thereby reading the first valid signal SPD MCG_SHS of the photoelectric conversion circuit 11 under medium conversion gain.

[0085] In one embodiment of the present invention, Figure 4 and Figure 5 As shown, after obtaining the first valid signal of the photoelectric conversion circuit 11 under the medium conversion gain, the controller is also used to: control the three conversion gain control transistors TCG and the first transfer transistor TX4 to be turned on, so as to control the first transfer transistor TX4 to be turned off when the charge of the first photodiode PD4 is transferred to the floating diffusion node FD1, the first overflow circuit 121 and the second overflow circuit 122, so as to obtain the first valid signal of the photoelectric conversion circuit 11 under the low conversion gain.

[0086] In an embodiment, in combination Figure 4 and Figure 5 As shown, at time T5, after obtaining the first valid signal SPD MCG_SHS of the photoelectric conversion circuit 11 under the medium conversion gain, the controller controls the three conversion gain control transistors TCG and the first transfer transistor TX4 to be turned on, and the charge of the first photodiode PD4 is transferred to the floating diffusion node FD1, the first overflow circuit 121 and the second overflow circuit 122. When the charge transfer in the first photodiode PD4 is completed, the controller controls the first transfer transistor TX4 to be turned off, thereby reading the first valid signal SPD LCG_SHS of the photoelectric conversion circuit 11 under the low conversion gain, ensuring the accuracy of the signal reading.

[0087] In one embodiment of the present invention, Figure 4 As shown, the signal output circuit 12 further includes: a reset transistor RST, a source of the reset transistor RST is connected to one end of the second overflow circuit 122, and a drain of the reset transistor RST is connected to the power supply voltage.

[0088] In an embodiment, Figure 4 As shown, the source of the reset transistor RST is connected to one end of the second overflow circuit 122, and the drain of the reset transistor RST is connected to the power supply voltage. By controlling the reset transistor RST to be turned on, the charge in the overflow circuit can be reset.

[0089] In one embodiment of the present invention, Figure 4 and Figure 5 As shown, after obtaining the first valid signal of the photoelectric conversion circuit 11 under low conversion gain, the controller is also used to: control the reset transistor RST to be turned on, so as to control the reset transistor RST to be turned off when the floating diffusion node FD1, the first overflow capacitor FD2 and the second overflow capacitor FD3 are reset, so as to obtain the first reset signal of the photoelectric conversion circuit 11 under low conversion gain.

[0090] In an embodiment, in combination Figure 4 and Figure 5 As shown, at time T6, after obtaining the first valid signal SPD LCG_SHS of the photoelectric conversion circuit 11 under low conversion gain, the controller controls the reset transistor RST to turn on, so that the charges in the floating diffusion node FD1, the first overflow capacitor FD2 and the second overflow capacitor FD3 flow into the power supply voltage through the reset transistor RST, thereby completing the reset of the floating diffusion node FD1, the first overflow capacitor FD2 and the second overflow capacitor FD3. When the reset is completed, the controller controls the reset transistor RST to turn off, so as to accurately obtain the first reset signal SPDLCG_SHR of the photoelectric conversion circuit 11 under low conversion gain.

[0091] In one embodiment of the present invention, Figure 4 and Figure 5 As shown, after obtaining the first reset signal of the photoelectric conversion circuit 11 under low conversion gain, the controller is also used to: control the dual conversion gain control transistor DCG to be turned on to obtain the second reset signal of the photoelectric conversion circuit 11 under medium conversion gain.

[0092] In an embodiment, in combination Figure 4 and Figure 5 As shown, at time T7, after obtaining the first reset signal SPD LCG_SHR of the photoelectric conversion circuit 11 under low conversion gain, the controller controls the dual conversion gain control transistor DCG to turn on. At this time, the signal in the second photodiode is read, and the signal is the second reset signal LPDMCG_SHR of the photoelectric conversion circuit 11 under medium conversion gain, thereby improving the accuracy of signal reading.

[0093] In one embodiment of the present invention, Figure 4 and Figure 5 As shown, after obtaining the second reset signal of the photoelectric conversion circuit 11 under the medium conversion gain, the controller is also used to: control the dual conversion gain control transistor DCG to turn off to obtain the second reset signal of the photoelectric conversion circuit 11 under the high conversion gain.

[0094] In an embodiment, in combination Figure 4 and Figure 5As shown, at time T8, after obtaining the second reset signal LPD MCG_SHR of the photoelectric conversion circuit 11 under the medium conversion gain, the controller controls the dual conversion gain control transistor DCG to turn off, and reads the signals in the second photodiodes PD1, PD2, and PD3 again, thereby accurately reading the second reset signal LPD HCG_SHR of the photoelectric conversion circuit 11 under the high conversion gain.

[0095] In one embodiment of the present invention, Figure 4 and Figure 5 As shown, after obtaining the second reset signal of the photoelectric conversion circuit 11 under high conversion gain, the controller is also used to: control the second transfer transistor to be turned on, so that when the charge in the second photodiode is transferred to the floating diffusion node FD1, the second transfer transistor is controlled to be turned off, so as to obtain the second effective signal of the photoelectric conversion circuit 11 under high conversion gain.

[0096] In an embodiment, in combination Figure 4 and Figure 5 As shown, at time T9, after obtaining the second reset signal LPD HCG_SHR of the photoelectric conversion circuit 11 under high conversion gain, the controller controls the second transfer transistors TX1, TX2, and TX3 to be turned on, and the charges accumulated in the second photodiodes PD1, PD2, and PD3 are transferred to the floating diffusion node FD1, that is, the second transfer transistor TX1 is turned on to transfer the charges accumulated in the second photodiode PD1, the second transfer transistor TX2 is turned on to transfer the charges accumulated in the second photodiode PD2, and the second transfer transistor TX3 is turned on to transfer the charges accumulated in the second photodiode PD3. Finally, the charges at these three places are all transferred to the floating diffusion node FD1. After the charge transfer is completed, the controller controls the second transfer transistors TX1, TX2, and TX3 to be turned off, so that the second effective signal LPD HCG_SHS of the photoelectric conversion circuit 11 under high conversion gain can be accurately read.

[0097] In one embodiment of the present invention, Figure 4 and Figure 5 As shown, after obtaining the second effective signal of the photoelectric conversion circuit 11 under high conversion gain, the controller is also used to: control the dual conversion gain control transistor DCG and the second transfer transistor to be turned on, so that when the charge in the second photodiode is transferred to the floating diffusion node FD1 and the first overflow capacitor FD2, the second transfer transistor is controlled to be turned off to obtain the second effective signal of the first photoelectric conversion circuit 11 under medium conversion gain.

[0098] In an embodiment, in combination Figure 4 and Figure 5As shown, at time T10, after obtaining the second effective signal LPD HCG_SHS of the photoelectric conversion circuit 11 under high conversion gain, the controller controls the dual conversion gain control transistor DCG and the second transfer transistors TX1, TX2, and TX3 to be turned on, so that the charges in the second photodiodes PD1, PD2, and PD3 are transferred to the floating diffusion node FD1 and the first overflow capacitor FD2. At this time, the controller controls the second transfer transistors TX1, TX2, and TX3 to be turned off to read the second effective signal LPD MCG_SHS of the first photoelectric conversion circuit 11 under medium conversion gain, thereby improving the accuracy of signal reading.

[0099] In one embodiment of the present invention, Figure 4 As shown, the signal output circuit 12 also includes: an amplifier transistor SF and a row selection transistor RS, the drain of the amplifier transistor SF is connected to the power supply voltage, and the gate of the amplifier transistor SF is connected to the floating diffusion node FD1; the source of the row selection transistor RS is connected to the source of the amplifier transistor SF, and the drain of the row selection transistor RS is connected to the signal reading circuit.

[0100] In an embodiment, Figure 4 As shown, the drain of the amplifier transistor SF is connected to the power supply voltage, so that the drain of the amplifier transistor SF can directly obtain the power supply of the power supply voltage to power the amplifier transistor SF. The gate of the amplifier transistor SF is connected to the floating diffusion node FD1. The floating diffusion transistor FD1 can collect and store the charges after photoelectric conversion. The source of the amplifier transistor SF is connected to the source of the row selection transistor RS, so that the row selection transistor RS can receive the signal in the amplifier transistor SF. The drain of the row selection transistor RS is connected to the signal reading circuit, so that the output signal of the amplifier transistor SF can be transmitted to the signal reading circuit through its drain terminal to convert the optical signal into an electrical signal and read it out.

[0101] In one embodiment of the present invention, when controlling the first photoelectric conversion sub-circuit 110, the first overflow circuit 121 and the second overflow circuit 122 to be turned on, the controller is specifically used to: control the photoelectric conversion sub-circuit 110, the first overflow circuit 121 and the second overflow circuit 122 to be turned on to a preset opening.

[0102] In an embodiment, the controller controls the first photoelectric conversion sub-circuit 110, the first overflow circuit 121 and the second overflow circuit 122 to be turned on to a preset opening, that is, not completely turned off. When the charge of the photoelectric conversion circuit 11 exceeds the load range, the excess charge can be transmitted based on the formed overflow path, thereby improving the detection range of high-intensity light.

[0103] In summary, according to the image sensor 10 of the embodiment of the present invention, by controlling the first photoelectric conversion sub-circuit 110, the first overflow circuit 121 and the second overflow circuit 122 to be turned off to a preset opening and when the barrier height of the first photoelectric conversion sub-circuit 110 and the barrier height of the first overflow circuit 121 and the second overflow circuit 122 meet the preset conditions, the charge in the first photoelectric conversion sub-circuit 110 can be transmitted to the first overflow circuit 121 and the second overflow circuit 122 to form an overflow path composed of the first photoelectric conversion sub-circuit 110, the floating diffusion node FD1, the first overflow circuit 121 and the second overflow circuit 122, and the excess charge after the first photoelectric conversion sub-circuit 110 is fully loaded is transmitted through the overflow path to form an overflow path that can accommodate the excess charge. While improving the charge accommodation range, the detection range of the pixel structure in the image sensor 10 to high-intensity light is improved, thereby effectively improving the dynamic range and flicker suppression.

[0104] A second aspect of the present invention provides a control method for an image sensor, which is used for the image sensor described in any one of the above embodiments of the present invention. The image sensor includes a photoelectric conversion circuit, a signal output circuit and a controller. The signal output circuit includes a floating diffusion node, a first overflow circuit and a second overflow circuit. The photoelectric conversion circuit includes a first photoelectric conversion sub-circuit. The control method includes: controlling the first photoelectric conversion sub-circuit, the first overflow circuit and the second overflow circuit to be turned on and when the barrier heights of the first photoelectric conversion sub-circuit, the first overflow circuit and the second overflow circuit meet the set conditions, the first photoelectric conversion sub-circuit, the floating diffusion node, the first overflow circuit and the second overflow circuit form an overflow path.

[0105] Specifically, by controlling the conduction state of the first photoelectric conversion sub-circuit, the first overflow circuit and the second overflow circuit, these elements are turned on to a preset opening, and at the same time, the barrier heights of these elements are controlled so that the barrier heights of these elements meet the set conditions. When these conditions are met, the first photoelectric conversion sub-circuit, the floating diffusion node, the first overflow circuit and the second overflow circuit will form an effective overflow path, which can allow excess charge to flow from the photoelectric conversion circuit to the floating diffusion node, the first overflow circuit and the second overflow circuit, thereby avoiding excessive charge accumulation in the floating diffusion node, resulting in signal distortion or image quality degradation.

[0106] According to the control method of the image sensor of the embodiment of the present invention, by controlling the first photoelectric conversion sub-circuit, the first overflow circuit and the second overflow circuit to be turned off to a preset opening and when the barrier height of the first photoelectric conversion sub-circuit and the barrier height of the first overflow circuit and the second overflow circuit meet the preset conditions, the charge in the first photoelectric conversion sub-circuit can be transmitted to the first overflow circuit and the second overflow circuit to form an overflow path composed of the first photoelectric conversion sub-circuit, the floating diffusion node, the first overflow circuit and the second overflow circuit, and the excess charge after the first photoelectric conversion sub-circuit is fully loaded is transmitted through the overflow path to form an overflow path that can accommodate the excess charge, while improving the charge accommodation range, the detection range of the pixel structure in the image sensor to high-intensity light is improved, thereby effectively improving the dynamic range and flicker suppression.

[0107] In one embodiment of the present invention, the first photoelectric conversion sub-circuit includes: a first photodiode, the anode of the first photodiode is grounded; a first transfer transistor, the source of the first transfer transistor is connected to the cathode of the first photodiode, and the drain of the first transfer transistor is connected to the floating diffusion node, which is used to turn on or off the overflow path between the first photodiode and the floating diffusion node.

[0108] In one embodiment of the present invention, the barrier heights of the first photoelectric conversion sub-circuit, the first overflow circuit and the second overflow circuit meet set conditions, including: the barrier height of the first photoelectric conversion sub-circuit is higher than the barrier height of the first overflow circuit and the barrier height of the first overflow circuit is higher than the barrier height of the second overflow circuit.

[0109] In one embodiment of the present invention, the photoelectric conversion circuit further includes: a second photoelectric conversion sub-circuit.

[0110] In one embodiment of the present invention, the second photoelectric conversion subcircuit includes: a second photodiode, the anode of the second photodiode is grounded; a second transfer transistor, the source of the second transfer transistor is connected to the cathode of the second photodiode, and the drain of the second transfer transistor is connected to the floating diffusion node.

[0111] In one embodiment of the present invention, when controlling the first photoelectric conversion sub-circuit, the first overflow circuit and the second overflow circuit to be turned on, the method further includes: controlling the second transfer transistor to be turned off.

[0112] In one embodiment of the present invention, the first overflow circuit includes: a dual conversion gain control transistor, the source of which is connected to the floating diffusion node; and a first overflow capacitor, one end of which is connected to the drain of the dual conversion gain control transistor.

[0113] In one embodiment of the present invention, the second overflow circuit includes: three conversion gain control transistors, the source of the three conversion gain control transistors is connected to the other end of the first overflow capacitor; a second overflow capacitor, one end of the second overflow capacitor is connected to the drain end of the three conversion gain control transistors.

[0114] In one embodiment of the present invention, after controlling the first photoelectric conversion sub-circuit, the first overflow circuit and the second overflow circuit to be turned on, it also includes: controlling the three conversion gain control transistors and the first transmission transistor to be turned off, and after the three conversion gain control transistors and the first transmission transistor are turned off, controlling the dual conversion gain control transistor to be turned on, so as to obtain a first reset signal of the photoelectric conversion circuit under a medium conversion gain.

[0115] In one embodiment of the present invention, after obtaining the first reset signal of the photoelectric conversion circuit at a medium conversion gain, the method further includes: controlling the dual conversion gain control transistor to turn off to obtain the first reset signal of the photoelectric conversion circuit at a high conversion gain.

[0116] In one embodiment of the present invention, after obtaining the first reset signal of the photoelectric conversion circuit at a high conversion gain, it also includes: controlling the first transfer transistor to be turned on so that when the charge in the first photodiode is transferred to the floating diffusion node, the first transfer transistor is controlled to be turned off so as to obtain the first valid signal of the photoelectric conversion circuit at a high conversion gain.

[0117] In one embodiment of the present invention, after obtaining the first effective signal of the photoelectric conversion circuit under high conversion gain, it also includes: controlling the dual conversion gain control transistor and the first transfer transistor to be turned on, so as to control the first transfer transistor to be turned off when the charge of the first photodiode is transferred to the floating diffusion node and the first overflow circuit, so as to obtain the first effective signal of the photoelectric conversion circuit under medium conversion gain.

[0118] In one embodiment of the present invention, after obtaining the first effective signal of the photoelectric conversion circuit under medium conversion gain, it also includes: controlling the three conversion gain control transistors and the first transfer transistor to be turned on, so as to control the first transfer transistor to be turned off when the charge of the first photodiode is transferred to the floating diffusion node, the first overflow circuit and the second overflow circuit, so as to obtain the first effective signal of the photoelectric conversion circuit under low conversion gain.

[0119] In one embodiment of the present invention, the signal output circuit further includes: a reset transistor, a source of the reset transistor is connected to one end of the second overflow circuit, and a drain of the reset transistor is connected to the power supply voltage.

[0120] In one embodiment of the present invention, after obtaining the first valid signal of the photoelectric conversion circuit under low conversion gain, it also includes: controlling the reset transistor to be turned on, so that when the floating diffusion node, the first overflow capacitor and the second overflow capacitor are reset, the reset transistor is controlled to be turned off, so as to obtain the first reset signal of the photoelectric conversion circuit under low conversion gain.

[0121] In one embodiment of the present invention, after obtaining the first reset signal of the photoelectric conversion circuit at low conversion gain, it also includes: controlling the dual conversion gain control transistor to be turned on to obtain the second reset signal of the photoelectric conversion circuit at medium conversion gain.

[0122] In one embodiment of the present invention, after obtaining the second reset signal of the photoelectric conversion circuit at a medium conversion gain, the method further includes: controlling the dual conversion gain control transistor to turn off to obtain the second reset signal of the photoelectric conversion circuit at a high conversion gain.

[0123] In one embodiment of the present invention, after obtaining the second reset signal of the photoelectric conversion circuit at a high conversion gain, it also includes: controlling the second transfer transistor to be turned on, so that when the charge in the second photodiode is transferred to the floating diffusion node, the second transfer transistor is controlled to be turned off, so as to obtain a second effective signal of the photoelectric conversion circuit at a high conversion gain.

[0124] In one embodiment of the present invention, after obtaining the second effective signal of the photoelectric conversion circuit under high conversion gain, it also includes: controlling the dual conversion gain control transistor and the second transfer transistor to be turned on, so that when the charge in the second photodiode is transferred to the floating diffusion node and the first overflow capacitor, the second transfer transistor is controlled to be turned off to obtain the second effective signal of the first photoelectric conversion circuit under medium conversion gain.

[0125] In one embodiment of the present invention, the signal output circuit also includes: an amplifying transistor, the drain of which is connected to the power supply voltage, and the gate of which is connected to the floating diffusion node; a row selecting transistor, the source of which is connected to the source of the amplifying transistor, and the drain of which is connected to the signal reading circuit.

[0126] In one embodiment of the present invention, controlling the first photoelectric conversion subcircuit, the first overflow circuit and the second overflow circuit to be turned on includes: controlling the photoelectric conversion subcircuit, the first overflow circuit and the second overflow circuit to be turned on to a preset opening.

[0127] According to the control method of the image sensor of the embodiment of the present invention, by controlling the first photoelectric conversion sub-circuit, the first overflow circuit and the second overflow circuit to be turned off to a preset opening and when the barrier height of the first photoelectric conversion sub-circuit and the barrier height of the first overflow circuit and the second overflow circuit meet the preset conditions, the charge in the first photoelectric conversion sub-circuit can be transmitted to the first overflow circuit and the second overflow circuit to form an overflow path composed of the first photoelectric conversion sub-circuit, the floating diffusion node, the first overflow circuit and the second overflow circuit, and the excess charge after the first photoelectric conversion sub-circuit is fully loaded is transmitted through the overflow path to form an overflow path that can accommodate the excess charge, while improving the charge accommodation range, the detection range of the pixel structure in the image sensor to high-intensity light is improved, thereby effectively improving the dynamic range and flicker suppression.

[0128] A third aspect of the present invention provides a non-temporary computer-readable storage medium on which a control program for an image sensor is stored. When the control program for the image sensor is executed by a processor, the control method for the image sensor described in any one of the above embodiments of the present invention is implemented.

[0129] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials, or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example.

[0130] Although the embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the claims and their equivalents.

Claims

1. An image sensor, characterized in that: include: A photoelectric conversion circuit, the photoelectric conversion circuit comprising a first photoelectric conversion sub-circuit; a signal output circuit, the signal output circuit comprising a floating diffusion node, a first overflow circuit and a second overflow circuit, one end of the first overflow circuit is connected to the floating diffusion node, and the other end of the first overflow circuit is connected to one end of the second overflow circuit; A controller is used to control the first photoelectric conversion sub-circuit, the first overflow circuit and the second overflow circuit to be turned on and when the barrier heights of the first photoelectric conversion sub-circuit, the first overflow circuit and the second overflow circuit meet the set conditions, the first photoelectric conversion sub-circuit, the floating diffusion node, the first overflow circuit and the second overflow circuit form an overflow path.

2. The image sensor according to claim 1, characterized in that The first photoelectric conversion sub-circuit comprises: a first photodiode, wherein an anode of the first photodiode is grounded; A first transfer transistor, wherein the source of the first transfer transistor is connected to the cathode of the first photodiode, and the drain of the first transfer transistor is connected to the floating diffusion node, and is used to turn on or off an overflow path between the first photodiode and the floating diffusion node.

3. The image sensor according to claim 2, characterized in that The potential barrier heights of the first photoelectric conversion sub-circuit, the first overflow circuit, and the second overflow circuit meet a set condition, including: A barrier height of the first transfer transistor is higher than a barrier height of the first overflow circuit and a barrier height of the first overflow circuit is higher than a barrier height of the second overflow circuit.

4. The image sensor according to claim 1 or 3, characterized in that: The photoelectric conversion circuit further includes: a second photoelectric conversion sub-circuit.

5. The image sensor according to claim 4, characterized in that: The second photoelectric conversion subcircuit comprises: a second photodiode, wherein an anode of the second photodiode is grounded; A second transfer transistor, a source of the second transfer transistor is connected to the cathode of the second photodiode, and a drain of the second transfer transistor is connected to the floating diffusion node.

6. The image sensor according to claim 5, characterized in that When controlling the first photoelectric conversion sub-circuit, the first overflow circuit and the second overflow circuit to be turned on, the controller is further used to: control the second transfer transistor to be turned off.

7. The image sensor according to claim 1 or 6, characterized in that: The first overflow circuit comprises: a dual conversion gain control transistor, the source of the dual conversion gain control transistor being connected to the floating diffusion node; A first overflow capacitor, wherein the other end of the first overflow capacitor is connected to the drain of the dual conversion gain control transistor.

8. The image sensor according to claim 1 or 6, characterized in that: The second overflow circuit comprises: three conversion gain control transistors, wherein the sources of the three conversion gain control transistors are connected to the other end of the first overflow capacitor; A second overflow capacitor, one end of which is connected to the drain end of the three conversion gain control transistors.

9. The image sensor according to claim 8, characterized in that: After controlling the first photoelectric conversion sub-circuit, the first overflow circuit, and the second overflow circuit to be turned on, the controller is further used to: The three conversion gain control transistors and the first transmission transistor are controlled to be turned off, and after the three conversion gain control transistors and the first transmission transistor are turned off, the dual conversion gain control transistor is controlled to be turned on to obtain a first reset signal of the photoelectric conversion circuit under a medium conversion gain.

10. The image sensor according to claim 9, characterized in that: After obtaining the first reset signal of the photoelectric conversion circuit at the medium conversion gain, the controller is further used for: The dual conversion gain control transistor is controlled to be turned off to obtain a first reset signal of the photoelectric conversion circuit under high conversion gain.

11. The image sensor according to claim 10, characterized in that: After obtaining the first reset signal of the photoelectric conversion circuit under the high conversion gain, the controller is further used for: The first transfer transistor is controlled to be turned on, and when the charge in the first photodiode is transferred to the floating diffusion node, the first transfer transistor is controlled to be turned off, so as to obtain a first effective signal of the photoelectric conversion circuit under a high conversion gain.

12. The image sensor according to claim 11, characterized in that After acquiring the first valid signal of the photoelectric conversion circuit under high conversion gain, the controller is further used for: The dual conversion gain control transistor and the first transfer transistor are controlled to be turned on, so that when the charge of the first photodiode is transferred to the floating diffusion node and the first overflow circuit, the first transfer transistor is controlled to be turned off to obtain a first valid signal of the photoelectric conversion circuit under medium conversion gain.

13. The image sensor according to claim 12, characterized in that: After acquiring the first valid signal of the photoelectric conversion circuit at the medium conversion gain, the controller is further used for: The three conversion gain control transistors and the first transfer transistor are controlled to be turned on, so that when the charge of the first photodiode is transferred to the floating diffusion node, the first overflow circuit and the second overflow circuit, the first transfer transistor is controlled to be turned off to obtain a first valid signal of the photoelectric conversion circuit under low conversion gain.

14. The image sensor according to claim 1 or 13, characterized in that: The signal output circuit also includes: A reset transistor, wherein a source of the reset transistor is connected to one end of the second overflow circuit, and a drain of the reset transistor is connected to a power supply voltage.

15. The image sensor according to claim 14, characterized in that: After acquiring the first valid signal of the photoelectric conversion circuit at the low conversion gain, the controller is further used for: The reset transistor is controlled to be turned on, so that when the floating diffusion node, the first overflow capacitor and the second overflow capacitor are reset, the reset transistor is controlled to be turned off to obtain a first reset signal of the photoelectric conversion circuit under low conversion gain.

16. The image sensor according to claim 15, characterized in that After obtaining a first reset signal of the photoelectric conversion circuit at a low conversion gain, the controller is further used to: The dual conversion gain control transistor is controlled to be turned on to obtain a second reset signal of the photoelectric conversion circuit under a medium conversion gain.

17. The image sensor according to claim 16, characterized in that: After obtaining the second reset signal of the photoelectric conversion circuit at the medium conversion gain, the controller is further used for: The dual conversion gain control transistor is controlled to be turned off to obtain a second reset signal of the photoelectric conversion circuit under high conversion gain.

18. The image sensor according to claim 17, characterized in that: After obtaining the second reset signal of the photoelectric conversion circuit under the high conversion gain, the controller is further used for: The second transfer transistor is controlled to be turned on, so that when the charge in the second photodiode is transferred to the floating diffusion node, the second transfer transistor is controlled to be turned off to obtain a second effective signal of the photoelectric conversion circuit under a high conversion gain.

19. The image sensor according to claim 18, characterized in that After obtaining the second effective signal of the photoelectric conversion circuit at a high conversion gain, the controller is further used to: The dual conversion gain control transistor and the second transfer transistor are controlled to be turned on, so that when the charge in the second photodiode is transferred to the floating diffusion node and the first overflow capacitor, the second transfer transistor is controlled to be turned off to obtain a second effective signal of the first photoelectric conversion circuit under medium conversion gain.

20. The image sensor according to claim 1, characterized in that The signal output circuit also includes: an amplifying transistor, wherein a drain of the amplifying transistor is connected to a power supply voltage, and a gate of the amplifying transistor is connected to the floating diffusion node; A row selection transistor, wherein a source of the row selection transistor is connected to a source of the amplifying transistor, and a drain of the row selection transistor is connected to a signal reading circuit.

21. The image sensor according to claim 1, characterized in that When controlling the first photoelectric conversion sub-circuit, the first overflow circuit and the second overflow circuit to be turned on, the controller is specifically used to control the photoelectric conversion sub-circuit, the first overflow circuit and the second overflow circuit to be turned on to a preset opening.

22. A method for controlling an image sensor, characterized in that: For the image sensor according to any one of claims 1 to 19, the image sensor comprises a photoelectric conversion circuit, a signal output circuit and a controller, the signal output circuit comprises a floating diffusion node, a first overflow circuit and a second overflow circuit, the photoelectric conversion circuit comprises a first photoelectric conversion sub-circuit, and the control method comprises: The first photoelectric conversion sub-circuit, the first overflow circuit and the second overflow circuit are controlled to be turned on and when the barrier heights of the first photoelectric conversion sub-circuit, the first overflow circuit and the second overflow circuit meet the set conditions, the first photoelectric conversion sub-circuit, the floating diffusion node, the first overflow circuit and the second overflow circuit form an overflow path.

23. A non-transitory computer-readable storage medium, characterized in that: The computer-readable storage medium stores a control program for the image sensor, and when the control program for the image sensor is executed by the processor, the control method for the image sensor according to claim 22 is implemented.

Images