Pixel circuit, image sensor and electronic equipment

Abstract

The invention provides a pixel circuit, an image sensor and an electronic device, the pixel circuit comprises a photoelectric conversion unit and a signal readout unit, the photoelectric conversion unit comprises a signal end, a fixed end and a plurality of photodiodes located between the signal end and the fixed end, the signal end is electrically connected with a bias voltage, the fixed end is grounded, and the signal readout unit is electrically connected with the signal end. In this way, the photodiode can be conducted through the bias voltage between the signal end and the fixed end, so that the photodiode is reset, and spectral response is achieved. The signal reading unit comprises a control end, a first end and a second end, the control end is electrically connected with the signal end, the first end is electrically connected with power supply voltage, and a light response signal of the photoelectric conversion unit is output through the second end. Therefore, according to the pixel circuit, through the photoelectric conversion unit and the signal reading unit, spectral response and signal output can be simply realized, the signal processing difficulty is reduced, the imaging difficulty is reduced, and the imaging effect of color imaging is improved.

Description

Technical Field

[0001] The present application relates to the field of circuits, and particularly to a pixel circuit, an image sensor, and an electronic device. Background Art

[0002] In certain application scenarios, an image sensor can be used to image an item, so as to have a preliminary understanding of the general outline and material of the item. The image sensor can include a multispectral image sensor, and the multispectral image sensor can perform color imaging using multiple bands such as red (R), green (G), blue (B), and near-infrared (NIR). The imaging of the multispectral image sensor is widely used due to having multiple color information and clear details.

[0003] Currently, the multispectral image sensor mainly adopts a Bayer color filter array (CFA). As shown in Figure 1 , each pixel unit of the multispectral image sensor includes a red filter, a green filter, a blue filter, or a near-infrared filter. However, the red filter, the green filter, and the blue filter cannot filter infrared light, resulting in crosstalk of red light, green light, and blue light by near-infrared light during color imaging. In the subsequent imaging process, complex color recovery algorithms need to be adopted, increasing the calculation cost and also requiring a large storage space, that is, the imaging of the current multispectral sensor is relatively complex. Summary of the Invention

[0004] In view of this, the purpose of the present application is to provide a pixel circuit, an image sensor, and an electronic device, which can reduce the difficulty of signal processing, reduce the difficulty of imaging, and improve the imaging effect of color imaging.

[0005] The present application provides a pixel circuit, and the pixel circuit includes:

[0006] A photoelectric conversion unit, the photoelectric conversion unit includes: a signal terminal, a fixed terminal, and a plurality of photodiodes located between the signal terminal and the fixed terminal; the signal terminal is electrically connected to a bias voltage, and the fixed terminal is grounded;

[0007] A signal readout unit, the signal readout unit includes a control terminal, a first terminal, and a second terminal, the control terminal is electrically connected to the signal terminal, the first terminal is electrically connected to a power supply voltage, and the light response signal of the photoelectric conversion unit is output through the second terminal. Optionally, the conduction directions of adjacent photodiodes are opposite.

[0008] Optionally, the response spectral range of each photodiode is different.

[0009] Optionally, the signal readout unit includes a plurality of signal readout devices, and the number of the signal readout devices is the same as the number of the photodiodes.

[0010] Optionally, the signal reading device includes a P-type metal oxide semiconductor (PMOS) transistor and an N-type metal oxide semiconductor (NMOS) transistor connected in series. The gates of the PMOS transistor and the NMOS transistor are both electrically connected to the signal terminal, and the power supply voltage is electrically connected to one of the source or drain of the PMOS transistor and the NMOS transistor; the other of the source or drain of the PMOS transistor is electrically connected to the other of the source or drain of the NMOS transistor, and they jointly serve as the output terminal of the light response signal.

[0011] Optionally, the pixel circuit further includes a reset unit, and the signal terminal is electrically connected to the bias voltage through the reset unit.

[0012] Optionally, the pixel circuit further includes a switch unit. One end of the switch unit is electrically connected to the signal terminal, the other end of the switch unit is electrically connected to the reset unit, and is also electrically connected to the control terminal of the signal reading unit.

[0013] Optionally, the pixel circuit further includes a charge storage unit. One end of the charge storage unit is grounded, the other end of the charge storage unit is electrically connected to the switch unit, and is also electrically connected to the control terminal of the signal reading unit.

[0014] Optionally, the pixel circuit further includes a signal output unit. The second end of the signal reading unit is electrically connected to the column output line through the signal output unit.

[0015] Optionally, the pixel circuit further includes a signal output unit. The second end of the signal reading unit is electrically connected to the column output line through the signal output unit.

[0016] The present application provides an image sensor, including a pixel array and a control circuit. The pixel array includes at least one pixel circuit as described in any one of the above, and the control circuit is electrically connected to the control terminal of the control device in each pixel circuit to control the conduction or cutoff of the control device in each pixel circuit.

[0017] The present application provides an electronic device, including the image sensor as described above.

[0018] The present application provides a pixel circuit. The pixel circuit includes a photoelectric conversion unit and a signal readout unit. The photoelectric conversion unit includes a signal terminal, a fixed terminal, and a plurality of photodiodes located between the signal terminal and the fixed terminal. The signal terminal is electrically connected to a bias voltage, and the fixed terminal is grounded. In this way, the bias voltage between the signal terminal and the fixed terminal can be used to turn on the photodiodes, so that the photodiodes are reset to achieve spectral response. The signal readout unit includes a control terminal, a first terminal, and a second terminal. The control terminal is electrically connected to the signal terminal, the first terminal is electrically connected to a power supply voltage, and the light response signal of the photoelectric conversion unit is output through the second terminal. It can be seen that the pixel circuit of the present application can simply achieve spectral response and signal output through the photoelectric conversion unit and the signal readout unit, reduce the difficulty of signal processing, reduce the difficulty of imaging, and improve the imaging effect of color imaging. Description of the Drawings

[0019] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the drawings in the following description are some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0020] Figure 1 Shows a schematic diagram of a multi-spectral image sensor;

[0021] Figure 2 Shows a top view structural schematic diagram of a photoelectric conversion unit provided by an embodiment of the present application;

[0022] Figure 3 Shows a cross-sectional structural schematic diagram of a photoelectric conversion unit provided by an embodiment of the present application;

[0023] Figure 4 Shows a cross-sectional structural schematic diagram of another photoelectric conversion unit provided by an embodiment of the present application;

[0024] Figure 5 Shows a cross-sectional structural schematic diagram of yet another photoelectric conversion unit provided by an embodiment of the present application;

[0025] Figure 6 Shows a cross-sectional structural schematic diagram of yet another photoelectric conversion unit provided by an embodiment of the present application;

[0026] Figure 7 Shows an equivalent circuit diagram of a photoelectric conversion unit provided by an embodiment of the present application;

[0027] Figure 8 Shows an equivalent circuit diagram of another photoelectric conversion unit provided by an embodiment of the present application;

[0028] Figure 9 The top view structural schematic diagram of a photoelectric conversion unit provided by an embodiment of the present application is shown;

[0029] Figures 10 - 13 The circuit schematic diagrams of multiple pixel circuits provided by an embodiment of the present application are shown. Detailed implementation manners

[0030] In order to enable those skilled in the art to better understand the solution of the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present application.

[0031] Many specific details are set forth in the following description in order to provide a thorough understanding of the present application, but the present application may be implemented in other ways different from those described herein. Those skilled in the art can make similar extensions without departing from the connotation of the present application. Therefore, the present application is not limited by the specific embodiments disclosed below.

[0032] The present application is described in detail in conjunction with the schematic diagrams. When detailing the embodiments of the present application, for the convenience of description, the cross-sectional views showing the device structure will be enlarged locally out of the general scale, and the schematic diagrams are only examples, which should not limit the protection scope of the present application herein. In addition, in actual production, three-dimensional spatial dimensions including length, width and depth should be included.

[0033] In some application scenarios, an image sensor can be used to image an item, so as to have a preliminary understanding of the general outline and material of the item. Lights of different bands can carry different types of information. For example, visible-band light can provide a color scene composed of three primary colors of red (R), green (G), and blue (B), and near-infrared (NIR)-band light can provide more material and contour details in imaging under low-light conditions.

[0034] The image sensor can include a multispectral image sensor, and the multispectral image sensor can perform color imaging using multiple bands such as red (R), green (G), blue (B), and near-infrared (NIR). The imaging of the multispectral image sensor is widely used due to its multiple color information and clear details.

[0035] Currently, the multispectral image sensor mainly adopts a Bayer color filter array (CFA), refer to Figure 1As shown, each pixel unit of the multispectral image sensor includes a red filter, a green filter, a blue filter, or a near-infrared filter. The red filter, green filter, and blue filter are selective for red light, green light, and blue light respectively, but the red filter, green filter, and blue filter cannot filter infrared light, resulting in crosstalk of red light, green light, and blue light by near-infrared light during color imaging, reducing the imaging effect of color imaging.

[0036] The multispectral image sensor based on the Bayer color filter array can use an infrared cut-off filter (IRCF) to move mechanically during detection or use two dynamically changing alternating optical paths to separate red light, green light, blue light, and near-infrared light without introducing parallax, but this greatly increases the imaging cost, form factor, and frame delay of imaging. And the above method still cannot completely eliminate the spectral crosstalk of infrared light, and a complex color restoration algorithm needs to be used in the subsequent imaging process, increasing the computational cost and also requiring a large storage space, that is, the imaging of the current multispectral sensor is relatively complex.

[0037] Based on this, the present application provides a pixel circuit. The pixel circuit includes a photoelectric conversion unit and a signal readout unit. The photoelectric conversion unit includes a signal terminal, a fixed terminal, and a plurality of photodiodes located between the signal terminal and the fixed terminal. The signal terminal is electrically connected to a bias voltage, and the fixed terminal is grounded. In this way, the bias voltage between the signal terminal and the fixed terminal can be used to turn on the photodiode, so that the photodiode is reset to achieve spectral response. The signal readout unit includes a control terminal, a first terminal, and a second terminal. The control terminal is electrically connected to the signal terminal, the first terminal is electrically connected to the power supply voltage, and the light response signal of the photoelectric conversion unit is output through the second terminal. It can be seen that the pixel circuit of the present application can simply achieve spectral response and signal output through the photoelectric conversion unit and the signal readout unit, reduce the difficulty of signal processing, reduce the difficulty of imaging, and improve the imaging effect of color imaging.

[0038] To better understand the technical solution and technical effect of the present application, the following will describe specific embodiments in detail with reference to the drawings.

[0039] The pixel circuit provided in this embodiment includes a photoelectric conversion unit 10 and a signal readout unit 500. Refer to Figures 10 - 13As shown in the figure. The photoelectric conversion unit 10 can also be called a pixel unit, and includes: a signal terminal, a fixed terminal A, and a plurality of photodiodes 100 located between the signal terminal and the fixed terminal A. The signal terminal is electrically connected to a bias voltage, and the fixed terminal A is grounded. In this way, the bias voltage between the signal terminal and the fixed terminal A can be used to turn on the photodiode, so that the photodiode is reset to achieve spectral response. The bias voltage is output by the bias voltage terminal 200. The signal readout unit 500 includes a control terminal, a first terminal, and a second terminal. The control terminal is electrically connected to the signal terminal of the photoelectric conversion unit 10, the first terminal is electrically connected to the power supply voltage, and the light response signal of the photoelectric conversion unit 10 is output through the second terminal. The power supply voltage is output by the power supply terminal 300.

[0040] Thus, it can be seen that the pixel circuit of the present application can simply achieve spectral response and signal output through the photoelectric conversion unit and the signal readout unit, reduce the difficulty of signal processing, reduce the difficulty of imaging, and improve the imaging effect of color imaging.

[0041] Since the most important component in the pixel circuit is the photodiode 100 in the photoelectric conversion unit 10, the structure of the photodiode 100 will be specifically introduced below:

[0042] The photoelectric conversion unit 10 is referenced Figure 2 As shown, it is a top view structure schematic diagram of a photoelectric conversion unit. The photoelectric conversion unit 10 includes a plurality of photodiodes 100 arranged in a stacked manner, referenced Figures 3 - 6 As shown, Figures 3 - 6 It is obtained by cutting along the Figure 2 NN direction in.

[0043] In the embodiment of the present application, each photodiode 100 includes an active layer 110, a hole transport layer 120, and an electron transport layer 130. The active layer 110 is located between the hole transport layer 120 and the electron transport layer 130. The hole transport layer 120 and the electron transport layer 130 are respectively used for hole transport and electron transport, and the combination of the two can assist the active layer in outputting electrical signals. The positions of the hole transport layer 120 and the electron transport layer 130 relative to the active layer 110 affect the conduction direction of the photodiode 100. The conduction direction of the photodiode 100 is from the hole transport layer 120 through the active layer 110 to the electron transport layer 130.

[0044] The material of the electron transport layer 130 can be [6,6]-phenyl-C61-butyric acid isooctyl ester (PCBM) or titanium oxide (TiO2).

[0045] The material of the hole transport layer 120 can be poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS), poly-3-hexylthiophene (P3HT), or nickel oxide (NiO).

[0046] The response spectral ranges of the active layers 110 of each photodiode 100 are different, so that the active layers 110 of different photodiodes 100 can respond to light of different wavelength bands, thereby reducing the situation of optical crosstalk. That is to say, due to the different response spectral ranges of the active layers 110 of different photodiodes 100, the response signals of different wavelength bands are output separately. Therefore, during the detection process, light of different wavelength bands will not crosstalk, thereby improving the imaging effect of color imaging.

[0047] Specifically, along the propagation direction of light in the pixel unit, the response spectral ranges of the active layers 110 of multiple photodiodes 100 gradually increase, so that the light can be gradually absorbed by the active layers 110 with different response spectral ranges in sequence, and then the response signals are output. If the response spectral ranges of the active layers 110 of multiple photodiodes 100 gradually decrease along the propagation direction of light, the active layer 110 that first receives the light will absorb all the light, resulting in the inability of the active layer 110 below it to perform signal response.

[0048] The material of the active layer 110 is a perovskite-type material. The perovskite-type material includes at least one halogen element, and the halogen element can be chlorine (Cl), bromine (Br), or iodine (I). The response spectral range of the perovskite-type material is adjusted by adjusting the proportion of at least one halogen element. Specifically, when the perovskite-type material includes only one halogen element, the response spectral range of the perovskite-type material can be adjusted by adjusting the halogen element, for example, by replacing chlorine with iodine. When the perovskite-type material includes two or more halogen elements, the response spectral range of the perovskite-type material can be adjusted by adjusting the proportion between the halogen elements.

[0049] As a possible implementation, if the photoelectric conversion unit 10 includes 4 photodiodes 100 stacked in sequence, since the response spectral ranges of the active layers of multiple photodiodes 100 gradually increase along the propagation direction of light, the response spectral ranges of the perovskite-type materials of the 4 photodiodes 100 can be 360 - 500 nm, 460 - 620 nm, 570 - 710 nm, and 650 - 1000 nm respectively, that is, the perovskites of the 4 photodiodes 100 respond to blue light, green light, red light, and near-infrared light in sequence.

[0050] In practical applications, when adjusting the proportion of the halogen element, the cations of the perovskite-type material can also be adjusted to obtain different response spectral ranges.

[0051] As an example, the perovskite-type material is (MAPbCl3) x (FAPbBr3) 1-x or MAPb(Cl x Br1-x ) 3 (x = 0.4 - 0.6), the response spectral range of this perovskite material is 360 - 500 nm, that is, the response spectral range of this perovskite material is the spectral range of blue light.

[0052] As another example, the perovskite material is (MAPbBr3) x (FAPbI3) 1-x or MAPb(Br x I 1-x ) 3 (x = 0.67 - 0.75), the response spectral range of this perovskite material is 460 - 620 nm, that is, the response spectral range of this perovskite material is the spectral range of green light.

[0053] As yet another example, the perovskite material is (MAPbBr3) x (FAPbI3) 1-x or MAPb(Br x I 1-x ) 3 (x = 0.33 - 0.43), the response spectral range of this perovskite material is 570 - 710 nm, that is, the response spectral range of this perovskite material is the spectral range of red light.

[0054] As yet another example, the perovskite material is (MAPbI3) x (FASnI3) 1-x or MAPb x Sn 1-x I3 (x = 0.25 - 0.5), the response spectral range of this perovskite material is 650 - 1000 nm, that is, the response spectral range of this perovskite material is the spectral range of near-infrared light.

[0055] In the embodiments of the present application, the optoelectronic conversion unit 10 may further include an electrode layer 140. The electrode layer 140 is connected to a metal wire, and the electrode layer 140 and the metal wire are used for resetting the photodiode 100 and outputting a response signal. Each photodiode 100 includes two ends, and the two ends respectively use metal wires as signal transmission endpoints. Refer to Figure 7 as shown, Figure 7 is Figure 3 the equivalent circuit diagram of the optoelectronic conversion unit shown. That is, the equivalent circuit of each photodiode 100 includes two ends, and the photodiode 100 can be turned on by using the bias voltage between the two ends.

[0056] In an embodiment of the present application, before the active layer 110 of the photodiode 100 responds to light, multiple photodiodes 100 can be turned on respectively, so as to reset the photodiodes 100 and maintain the initial states of electrons and holes for responding to light. When light irradiates the photoelectric conversion unit 10, the active layer 110 of each photodiode 100 outputs a response signal to the light, so as to obtain the response result of each photoelectric conversion unit 10 based on multiple response signals subsequently.

[0057] In an embodiment of the present application, the structure of the photodiode 100 included in the photoelectric conversion unit 10 and the connection conditions of the electrode layer 140 and the metal wire may ultimately affect the equivalent circuit of the photodiode 100. The following is a specific introduction:

[0058] As a possible implementation manner, the electrode layer 140 can be disposed on both sides of each photodiode 100, and each electrode layer 140 can be connected to a metal wire. The metal wire can include a first metal wire 151 and a second metal wire 152. That is to say, the electrode layer 140 on one side of the photodiode 100 is connected to the first metal wire 151, and the electrode layer 140 on the other side of the photodiode 100 is connected to the second metal wire 152. The first metal wire 151 can be connected to a signal terminal, and the second metal wire 152 can be connected to a fixed terminal A. The photodiode 100 is turned on by using the bias voltage between the signal terminal and the fixed terminal A, that is, each photodiode 100 is turned on by using the bias voltage between the first metal wire 151 and the second metal wire 152. Wherein, the direction of the bias voltage between the signal terminal and the fixed terminal A is the same as the conduction direction of the photodiode 100 to be turned on.

[0059] As an example, refer to Figure 3 As shown, since each photodiode 100 has an electrode layer 140 and a metal wire, each photodiode 100 can be independently turned on and signal-transmitted. Refer to Figure 7 As shown. A bias voltage can be connected to one end of each photodiode 100, and the other end of each photodiode is grounded.

[0060] As another possible implementation manner, two adjacent photodiodes 100 can form a group of antipolarity channels, and the photodiodes 100 included in each group of antipolarity channels are not repeated. The conduction directions of the two photodiodes 100 in each antipolarity channel are opposite. In this way, the electrode layer 140 is disposed on both sides of the two photodiodes 100, and the metal wire is connected with the antipolarity channel as a whole. Each electrode layer 140 on both sides of the two photodiodes 100 can be connected to a metal wire. The metal wire can include a third metal wire 153 and a fourth metal wire 154. Refer to Figure 4As shown, that is to say, the electrode layers 140 on one side of the two photodiodes 100 are connected to the third metal wire 153, and the electrode layers 140 on the other side of the two photodiodes 100 are connected to the fourth metal wire 154. The third metal wire 153 can be connected to a signal terminal, and the fourth metal wire 154 can be connected to a fixed terminal A. In this way, the two photodiodes 100 included in the same set of anti-polarity channels share the same signal terminal and the same fixed terminal A. The photodiodes 100 are turned on by using the bias voltage between the signal terminal and the fixed terminal A, that is, each photodiode 100 in the anti-polarity channel is turned on by using the bias voltage between the third metal wire 153 and the fourth metal wire 154.

[0061] Since the conduction directions of the two photodiodes 100 in the anti-polarity channel are opposite, by adjusting the direction of the bias voltage between the signal terminal and the fixed terminal A, these two photodiodes 100 can be turned on separately. In this way, using the two photodiodes 100 with opposite conduction directions as a whole for signal transmission can reduce the difficulty of metal wire wiring, reduce the manufacturing difficulty of the multi-spectral image sensor, and reduce the cost.

[0062] In the embodiment of the present application, not only the conduction directions of the two photodiodes 100 in each anti-polarity channel are opposite, but also the conduction directions of adjacent photodiodes 100 are opposite. In this way, the arrangements of the two photodiodes 100 in each set of anti-polarity channels are the same. At this time, adjacent anti-polarity channels can also share the same electrode layer 140 or the same metal wire, that is, adjacent anti-polarity channels share the same fixed terminal A. In this way, multiple anti-polarity channels can be connected in parallel, which is convenient for simultaneously outputting the signals of multiple anti-polarity channels, thereby accelerating the detection speed.

[0063] The photodiodes 100 included in each set of anti-polarity channels are not repeated. At this time, a buffer layer 160 can be provided between the two photodiodes 100 included in each set of anti-polarity channels. The buffer layer can be used to block the penetration of the solvent when the active layer 110 is formed by the solution method, that is, the buffer layer is used to increase the solvent diffusion path length and improve the anti-permeability. And the buffer layer 160 can reduce the internal stress of the thin film.

[0064] As a possible implementation manner, along the propagation direction of light in the pixel unit, the anti-polarity channel includes a hole transport layer 120, an active layer 110, an electron transport layer 130, a buffer layer 160, an electron transport layer 130, an active layer 110, and a hole transport layer 120 stacked in sequence.

[0065] As an example, refer to Figure 5As shown, the pixel unit includes 4 photodiodes 100 stacked in sequence. Along the propagation direction of light in the pixel unit, the 4 photodiodes 100 respectively form 2 groups of antipolarity channels, and the conduction directions of the 2 photodiodes 100 in each group of antipolarity channels are opposite. The 2 groups of antipolarity channels share the same electrode layer 140 and the same fifth metal wire 155, and the fifth metal wire 155 is connected to the fixed terminal A. The materials of the electrode layer 140 and the buffer layer 160 can be indium tin oxide (ITO). Along the propagation direction of light, the materials of the active layer 110 are respectively (MAPbCl3) 0.5 (FAPbBr3) 0.5 、(MAPbBr3) 0.7 (FAPbI3) 0.3 、(MAPbBr3) 0.4 (FAPbI3) 0.6 and (MAPbI3) 0.5 (FASnI3) 0.5 , which are respectively responsive to blue light, green light, red light and near-infrared light. Along the propagation direction of light in the pixel unit, the 2 groups of antipolarity channels include 4 hole transport layers 120 and 4 electron transport layers 130. The materials of the hole transport layers 120 are respectively P3HT, NiO, P3HT and PEDOT:PSS, and the materials of the electron transport layers 130 are respectively TiO2, PCBM, TiO2 and PCBM. As an example, the fixed terminal A can be grounded, so that by only adjusting the magnitude and direction of the bias voltage of the signal terminal, the conduction directions of the 2 photodiodes 100 in the entire antipolarity channel can be adjusted.

[0066] Refer to Figure 8 As shown, it is the equivalent circuit diagram of the 4 photodiodes 100. Among them, the same fifth metal wire 155 shared by the 2 groups of antipolarity channels is connected to the same fixed terminal A, and each group of antipolarity channels is connected to the signal terminal. It is set that the signal terminal connected to the first group of antipolarity channels is the second signal terminal C, and the signal terminal connected to the second group of antipolarity channels is the first signal terminal B. When the pixel circuit works, the 2 antipolarity channels can operate independently in a parallel state because of the same arrangement and being respectively connected to the fixed terminal A and the signal terminal. Each antipolarity channel can adopt a sequential detection mode, and the conduction switching of the 2 photodiodes 100 is realized by changing the magnitude and direction of the bias voltage.

[0067] In the embodiments of the present application, the photodiodes 100 included in each set of antipodal channels may be repeated. The two photodiodes 100 included in each set of antipodal channels may share a common electron transport layer or a common hole transport layer. On both sides of the surface of the common electron transport layer or the common hole transport layer are the active layers 110 of different photodiodes 100 in the same set of antipodal channels. That is to say, there are two active layers 110, two hole transport layers 120 and one electron transport layer 130 or two active layers 110, one hole transport layer 120 and two electron transport layers 130 in a set of antipodal channels. This can reduce the device thickness and the manufacturing process, thereby reducing costs, and can also reduce the resistance and device complexity of the image sensor.

[0068] As a possible implementation, along the light propagation direction, the antipodal channel includes a hole transport layer 120, an active layer 110, an electron transport layer 130, an active layer 110 and a hole transport layer 120 stacked in sequence.

[0069] As an example, referring to Figure 6 As shown, the photoelectric conversion unit 10 includes four photodiodes 100 stacked in sequence. Along the light propagation direction, the four photodiodes 100 respectively form two sets of antipodal channels. The conduction directions of the two photodiodes 100 in each set of antipodal channels are opposite, and the two photodiodes 100 in each set of antipodal channels share the same electron transport layer 130. The two sets of antipodal channels share the same electrode layer 140 and the same fifth metal wire 155. The material of the electrode layer 140 may be indium tin oxide (ITO). Along the light propagation direction, the materials of the active layers 110 are (MAPbCl3) 0.5 (FAPbBr3) 0.5 、(MAPbBr3) 0.7 (FAPbI3) 0.3 、(MAPbBr3) 0.4 (FAPbI3) 0.6 and (MAPbI3) 0.5 (FASnI3) 0.5 , which are respectively responsive to blue light, green light, red light and near-infrared light. Along the light propagation direction, the materials of the hole transport layers 120 are P3HT, NiO, P3HT and PEDOT:PSS respectively, and the materials of the electron transport layers 130 are all PCBM.

[0070] To avoid solvent penetration when the active layer 110 is formed by the solution method, the active layer 110 may be formed by a vapor deposition method. To reduce the cost of the manufacturing process, along the reverse direction of light propagation, only the vapor deposition method may be used to form the active layer 110 located above the common electron transport layer in each antipodal channel. That is to say, only the vapor deposition method may be used to formFigure 5 (MAPbCl3) as shown 0.5 (FAPbBr3) 0.5 and (MAPbBr3) 0.4 (FAPbI3) 0.6 , (MAPbI3) 0.5 (FASnI3) 0.5 and (MAPbBr3) 0.7 (FAPbI3) 0.3 can still be formed by the solution method. Thus, when the material of the common electron transport layer is PCBM, since the active layer 110 above the common electron transport layer is not formed by the solution method and there is no solvent penetration, it is not necessary to use ITO and TiO2 to improve the impermeability, and the device resistance and complexity can be reduced.

[0071] In the embodiments of the present application, each photoelectric conversion unit 10 may further include a microlens structure 11. Along the opposite direction of the light propagation, the microlens structure 11 is disposed above the photodiode 100 that first receives light.

[0072] In the embodiments of the present application, an insulating layer 12 may also be disposed around the pixel unit. The material of the insulating layer 12 may be silicon oxide or silicon nitride. The insulating layer 12 is disposed around the sidewalls of the plurality of photodiodes 100 for isolating the plurality of photoelectric conversion units 10. Along the light propagation direction, the insulating layer 12 may also be disposed on the surface of the lowermost electrode layer 140 for protecting the photoelectric conversion unit 10. The metal wires connected to the electrode layer 140 may be disposed in the insulating layer 12, so that the signals of the photodiodes 100 can be led out. The metal wires may be led out from any one of the four sidewalls of the photodiode 100, and the specific lead-out may be set according to the actual situation. For example, the two metal wires of the same photodiode 100 may be led out from two adjacent or opposite sidewalls.

[0073] As a possible implementation manner, referring to Figure 5 or Figure 6 as shown, Figure 5 and Figure 6 may be obtained from the cross-section along the MM direction in Figure 10 . The pixel unit includes 4 photodiodes 100 stacked in sequence. Along the light propagation direction in the pixel unit, the 4 photodiodes 100 respectively form 2 groups of antipolarity channels, and the conduction directions of the 2 photodiodes 100 in each group of antipolarity channels are opposite. The 2 groups of antipolarity channels share the same electrode layer 140 and the same fifth metal wire 155.

[0074] Referring to Figure 10As shown, the electrode layer 140 shared by two groups of anti-polarity channels, i.e., the common electrode layer, is connected to the same fifth metal wire 155. The fifth metal wire 155 can be connected to the fixed end A. Along the propagation direction of light in the pixel unit, the electrode layer 140 of the first group of anti-polarity channels is connected to the third metal wire 153, and the third metal wire 153 is connected to the second signal terminal C. The electrode layer 140 of the second group of anti-polarity channels is connected to the fourth metal wire 154, and the fourth metal wire 154 is connected to the first signal terminal B.

[0075] Specifically, the positions of the fixed end A and the second signal terminal C can be adjacent. The fixed end A is arranged on the left side of the pixel unit, the second signal terminal C is arranged on the front side of the pixel unit, and the first signal terminal B is arranged at the bottom of the pixel unit. In the embodiment of the present application, to realize the output of the response signal of the photodiode 100, the pixel circuit may include a bias voltage terminal 200, a power supply terminal 300, a reset unit 400, a signal reading unit 500, and a signal output unit 600, as shown in Figures 10 - 13 As shown. Among them, the bias voltage terminal 200 can provide a bias voltage whose magnitude and direction can change. The power supply terminal 300 provides a constant power supply voltage. The signal terminal can be electrically connected to the bias voltage through the reset unit 400, that is, the reset unit 400 can control whether the photodiode 100 is turned on and control the output of the photodiode 100. The reset unit 400 can include a control terminal, a first terminal, and a second terminal. The signal output unit 600 can be used to output the response signal of the photodiode 100. The second terminal of the signal reading unit 500 is electrically connected to the column output line through the signal output unit 600. The signal output unit 600 can include a control terminal, a first terminal, and a second terminal.

[0076] The bias voltage terminal 200 is connected to the first signal terminal B and the second signal terminal C of the reset unit 400 and the photoelectric conversion unit 10. The control terminal of the signal reading unit 500 is connected to the first signal terminal B and the second signal terminal C of the photoelectric conversion unit 10. The power supply terminal 300 is connected to the first terminal of the signal reading unit 500. The signal output unit 600 is connected to the second terminal of the signal reading unit 500. In this way, each photodiode 100 can be turned on by using the bias voltage terminal 200 and the reset unit 400 respectively, and then the response signal of each photodiode 100 can be obtained by using the signal reading unit 500, and then the response signal can be output by using the signal output unit 600.

[0077] Specifically, the signal reading unit 500 includes a plurality of signal reading devices. The number of signal reading devices is the same as the number of photodiodes 100. In this way, each signal reading device corresponds to one photodiode 100 respectively, and it can be realized that each photodiode 100 has a signal reading device for signal output.

[0078] In an embodiment of the present application, the bias voltage terminal 200 and the reset unit 400 can conduct multiple photodiodes 100 simultaneously to output the response signals of the multiple photodiodes 100 at the same time, or can conduct each photodiode 100 in sequence, and the response signals of different photodiodes 100 are output separately in sequence. The above two situations correspond to different circuit designs. Taking the photoelectric conversion unit 10 including 4 photodiodes 100 stacked in sequence as an example, the specific introduction is as follows:

[0079] The photoelectric conversion unit 10 includes 4 photodiodes 100 stacked in sequence. Adjacent 2 photodiodes 100 can form a set of anti-polarity channels, and the conduction directions of the 2 photodiodes 100 in the anti-polarity channels are opposite. Along the reverse direction of the light propagation, the 4 photodiodes 100 are the first photodiode, the second photodiode, the third photodiode, and the fourth photodiode respectively. The first photodiode, the second photodiode, the third photodiode, and the fourth photodiode respond to near-infrared light, red light, green light, and blue light in sequence. The first photodiode and the second photodiode share the same first signal terminal B, the third photodiode and the fourth photodiode share the same second signal terminal C, and the first photodiode, the second photodiode, the third photodiode, and the fourth photodiode share the same fixed terminal A, and the fixed terminal A is grounded.

[0080] As a possible implementation manner, the response signals of different photodiodes 100 are output separately in sequence. The reset unit 400 includes a first reset device 410 and a second reset device 420. The signal reading unit 500 includes a first signal reading device 510, a second signal reading device 520, a third signal reading device 530, and a fourth signal reading device 540. The first signal reading device 510, the second signal reading device 520, the third signal reading device 530, and the fourth signal reading device 540 are connected in series.

[0081] As an example, the first signal reading device 510 and the third signal reading device 530 can be P-type metal-oxide-semiconductor (P-Mental-Oxide-Semiconductor, PMOS) transistors. The second signal reading device 520 and the fourth signal reading device 540 can be N-type metal-oxide-semiconductor (N-Mental-Oxide-Semiconductor, NMOS) transistors. The gates of the PMOS transistors and the gates of the NMOS transistors are both electrically connected to the signal terminals, and the power supply voltage is electrically connected to one of the sources or drains of the PMOS transistors and the NMOS transistors. The other of the source or drain of the PMOS transistor is electrically connected to the other of the source or drain of the NMOS transistor, and they are jointly used as the output terminal of the light response signal.

[0082] Reference Figure 10 As shown, the bias voltage terminal 200 is connected to the first signal terminal B by the first reset device 410, and the bias voltage terminal 200 is connected to the second signal terminal C by the second reset device 420. That is, the first reset device 410 is used to control the conduction of the first photodiode and the second photodiode, and the second reset device 420 is used to control the conduction of the third photodiode and the fourth photodiode. The first signal terminal B is respectively connected to the control terminals of the first signal reading device 510 and the second signal reading device 520, and the second signal terminal C is respectively connected to the control terminals of the third signal reading device 530 and the fourth signal reading device 540. That is, the first signal reading device 510 and the second signal reading device 520 are respectively used to read the response signals output by the first photodiode and the second photodiode, and the third signal reading device 530 and the fourth signal reading device 540 are respectively used to read the response signals of the third photodiode and the fourth photodiode. The second ends of the first signal reading device 510, the second signal reading device 520, the third signal reading device 530, and the fourth signal reading device 540 are connected to the signal output unit 600. Only one signal output unit 600 represents that the response signals of each photodiode are output sequentially.

[0083] As an example, when the bias voltage terminal 200 is negatively biased, that is, the direction of the bias voltage between the fixed terminal A and the first signal terminal B or the second signal terminal C is from the fixed terminal A to the first signal terminal B or the second signal terminal C. First, the first reset device 410 is turned on to reset the first photodiode and the second photodiode. Then the first reset device 410 is turned off, and the photoelectric conversion unit 10 is irradiated with light. If the light includes near-infrared light, the near-infrared light excites the first photodiode in the photoelectric conversion unit 10 to generate photo-generated carriers, causing the first signal reading device 510 to conduct. The response signal of the near-infrared light output by the first signal reading device 510 is read on the column output line through the signal output unit 600, and the signal output unit 600 is turned off after the reading is completed.

[0084] Then the second reset device 420 is turned on to reset the third photodiode and the fourth photodiode. Then the second reset device 420 is turned off, and the photoelectric conversion unit 10 is irradiated with light. If the light includes blue light, the blue light excites the fourth photodiode in the photoelectric conversion unit 10 to generate photo-generated carriers, causing the third signal reading device 530 to conduct. The response signal of the blue light output by the third signal reading device 530 is read on the column output line through the signal output unit 600, and the signal output unit 600 is turned off after the reading is completed.

[0085] When the bias voltage terminal 200 is forward-biased, that is, the direction of the bias voltage between the fixed terminal A and the first signal terminal B or the second signal terminal C is from the first signal terminal B or the second signal terminal C to the fixed terminal A. First, the first reset device 410 is turned on to reset the first photodiode and the second photodiode. Then the first reset device 410 is turned off, and the photoelectric conversion unit 10 is irradiated with light. If the light includes red light, the red light excites the second photodiode in the photoelectric conversion unit 10 to generate photo-generated carriers, causing the second signal reading device 520 to conduct. The response signal of the red light output by the second signal reading device 520 is read on the column output line through the signal output unit 600, and the signal output unit 600 is turned off after the reading is completed.

[0086] Then the second reset device 420 is turned on to reset the third photodiode and the fourth photodiode. Then the second reset device 420 is turned off, and the photoelectric conversion unit 10 is irradiated with light. If the light includes green light, the green light excites the third photodiode in the photoelectric conversion unit 10 to generate photo-generated carriers, causing the fourth signal reading device 540 to conduct. The response signal of the blue light output by the fourth signal reading device 540 is read on the column output line through the signal output unit 600, and the signal output unit 600 is turned off after the reading is completed.

[0087] As another possible implementation, the response signals of different photodiodes 100 are output simultaneously. The signal output unit 600 includes a first signal output device 610 and a second signal output device 620, and the signal reading unit 500 includes a first signal reading device 510, a second signal reading device 520, a third signal reading device 530, and a fourth signal reading device 540.

[0088] Reference Figure 11As shown, the bias voltage terminal 200 is connected to the first signal terminal B and the second signal terminal C respectively by the reset unit 400. That is, the reset unit 400 is used to control the conduction of the first photodiode and the second photodiode, and can also be used to control the conduction of the third photodiode and the fourth photodiode. The first signal terminal B is connected to the control terminals of the first signal reading device 510 and the second signal reading device 520 respectively, and the second signal terminal C is connected to the control terminals of the third signal reading device 530 and the fourth signal reading device 540 respectively. That is, the first signal reading device 510 and the second signal reading device 520 are respectively used to read the response signals output by the first photodiode and the second photodiode, and the third signal reading device 530 and the fourth signal reading device 540 are respectively used to read the response signals of the fourth photodiode and the third photodiode. The second ends of the first signal reading device 510 and the second signal reading device 520 are connected to the first signal output device 610, and the second ends of the third signal reading device 530 and the fourth signal reading device 540 are connected to the second signal output device 620. The two signal output devices respectively output the response signals of the two photodiodes in each anti-polarity channel, so that the response signals in different anti-polarity channels can be output simultaneously, greatly improving the detection efficiency.

[0089] As an example, when the bias voltage terminal 200 is negatively biased, that is, the direction of the bias voltage between the fixed terminal A and the first signal terminal B or the second signal terminal C is from the fixed terminal A to the first signal terminal B or the second signal terminal C. First, the reset unit 400 is turned on to reset the first photodiode, the second photodiode, the third photodiode, and the fourth photodiode. Then the reset unit 400 is turned off. When the photoelectric conversion unit 10 is irradiated with light, if the light includes near-infrared light and blue light, the near-infrared light and the blue light respectively excite the first photodiode and the fourth photodiode in the photoelectric conversion unit 10 to generate photocarriers, causing the first signal reading device 510 and the third signal reading device 530 to conduct. The response signal of the near-infrared light output by the first signal reading device 510 is read on the column output line 1 through the first signal output device 610, and the response signal of the blue light output by the third signal reading device 530 is read on the column output line 2 through the second signal output device 620. After the reading is completed, the first signal output device 610 and the second signal output device 620 are turned off.

[0090] When the bias voltage terminal 200 is forward-biased, that is, the direction of the bias voltage between the fixed terminal A and the first signal terminal B or the second signal terminal C is from the first signal terminal B or the second signal terminal C to the fixed terminal A. First, the reset unit 400 is turned on to reset the first photodiode, the second photodiode, the third photodiode, and the fourth photodiode. Then the reset unit 400 is turned off, and the photoelectric conversion unit 10 is irradiated with light. If the light includes red light and green light, the red light and the green light respectively excite the second photodiode and the third photodiode in the photoelectric conversion unit 10 to generate photo-generated carriers, so that the second signal readout device 520 and the fourth signal readout device 540 are turned on. The response signal of the red light output by the second signal readout device 520 is read on the column output line 1 through the first signal output device 610, and the response signal of the green light output by the fourth signal readout device 540 is read on the column output line 2 through the second signal output device 620. After the reading is completed, the first signal output device 610 and the second signal output device 620 are turned off.

[0091] In an embodiment of the present application, the multi-spectral image processing circuit may include a switching unit and a charge storage unit. The switching unit and the charge storage unit are used to jointly amplify the response signal output by the photodiode 100, thereby improving the signal-to-noise ratio. Specifically, one end of the switching unit is electrically connected to the signal terminal, the other end of the switching unit is electrically connected to the reset unit 400, and is electrically connected to the control terminal of the signal readout unit 500. The switching unit includes a control terminal, a first terminal, and a second terminal. The charge storage unit may be a capacitor. The signal terminal and the control terminal of the signal readout unit 500 are connected by the switching unit. The control terminal of the signal readout unit 500 and the switching unit are respectively connected to one end of the charge storage unit, and the other end of the charge storage unit is grounded. That is to say, the charge storage unit is the floating diffusion region of the photodiode, and the switching unit is a switch for controlling the connection between the charge storage unit and the photoelectric conversion unit 10.

[0092] The number of switching units is the same as the number of signal terminals of the photoelectric conversion unit 10, so as to ensure that each signal terminal can be controlled by the switching unit when outputting the response signal.

[0093] Since the response signals of different reverse-polarity channels can be output simultaneously or sequentially, the following continues to take the photoelectric conversion unit 10 including 4 photodiodes 100 stacked in sequence as an example for specific introduction:

[0094] The photoelectric conversion unit 10 includes four photodiodes 100 arranged in a stacked manner in sequence. Two adjacent photodiodes 100 can form a set of antipolarity channels, and the conduction directions of the two photodiodes 100 in the antipolarity channel are opposite. Along the reverse direction of the light propagation, the four photodiodes 100 are respectively a first photodiode, a second photodiode, a third photodiode, and a fourth photodiode. The first photodiode, the second photodiode, the third photodiode, and the fourth photodiode respond to near-infrared light, red light, green light, and blue light in sequence. The first photodiode and the second photodiode share the same first signal terminal B, the third photodiode and the fourth photodiode share the same second signal terminal C, and the first photodiode, the second photodiode, the third photodiode, and the fourth photodiode share the same fixed terminal A, and the fixed terminal A is grounded.

[0095] As a possible implementation manner, the response signals of different photodiodes 100 are output separately in sequence. The reset unit 400 includes a first reset device 410 and a second reset device 420. The signal reading unit 500 includes a first signal reading device 510, a second signal reading device 520, a third signal reading device 530, and a fourth signal reading device 540. The switching unit includes a first switching device 710 and a second switching device 720, and the charge storage unit includes a first charge storage device 810 and a second charge storage device 820.

[0096] Reference Figure 12As shown, the bias voltage terminal 200 is connected to the first signal terminal B by means of the first reset device 410, the first switching device 710. The bias voltage terminal 200 is connected to the second signal terminal C by means of the second reset device 420, the second switching device 720. The first signal terminal B is respectively connected to the control terminals of the first signal reading device 510 and the second signal reading device 520 by means of the first switching device 710. The second signal terminal C is respectively connected to the control terminals of the third signal reading device 530 and the fourth signal reading device 540 by means of the second switching device 720. The control terminals of the first signal reading device 510 and the second signal reading device 520 are connected to one end of the first charge storage device 810, and the other end of the first charge storage device 810 is grounded. The control terminals of the third signal reading device 530 and the fourth signal reading device 540 are connected to one end of the second charge storage device 820, and the other end of the second charge storage device 820 is grounded. That is, the first signal reading device 510 and the second signal reading device 520 are respectively used to read the response signals output by the first photodiode and the second photodiode, and are also used to read the residual charge stored in the first charge storage device 810. The third signal reading device 530 and the fourth signal reading device 540 are respectively used to read the response signals of the fourth photodiode and the third photodiode, and are also used to read the residual charge stored in the second charge storage device 820. The second ends of the first signal reading device 510, the second signal reading device 520, the third signal reading device 530, and the fourth signal reading device 540 are connected to the signal output unit 600. Only one signal output device represents that the response signals of each photodiode are output sequentially one by one.

[0097] As an example, when the bias voltage terminal 200 is negatively biased, that is, the direction of the bias voltage between the fixed terminal A and the first signal terminal B or the second signal terminal C is from the fixed terminal A to the first signal terminal B or the second signal terminal C. First, the first reset device 410 and the first switching device 710 are turned on to reset the first photodiode, the second photodiode, and the first charge storage device 810. Then the first reset device 410 and the first switching device 710 are turned off. When the photoelectric conversion unit 10 is irradiated with light, if the light includes near-infrared light, the near-infrared light excites the first photodiode, and the first photodiode converts the optical signal into an electrical signal through the photoelectric effect. The first reset device 410 is turned on to release the residual charge of the first charge storage device 810, and then the first reset device 410 is turned off and the first switching device 710 is turned on, so that the charge corresponding to the electrical signal enters the first charge storage device 810 from the first photodiode and the first signal reading device 510 is turned on. The response signal of the near-infrared light output by the first signal reading device 510 is read on the column output line through the signal output unit 600, and the signal output unit 600 is turned off after the reading is completed.

[0098] Then, the second reset device 420 and the second switching device 720 are turned on to reset the third photodiode, the fourth photodiode, and the second charge storage device 820. Then, the second reset device 420 and the second switching device 720 are turned off. When the photoelectric conversion unit 10 is irradiated with light, if the light includes blue light, the blue light excites the fourth photodiode. Through the photoelectric effect, the fourth photodiode converts the optical signal into an electrical signal. The second reset device 420 is turned on to enable the second charge storage device 820 to release residual charges. Then, the second reset device 420 is turned off and the second switching device 720 is turned on, so that the charges corresponding to the electrical signal enter the second charge storage device 820 from the fourth photodiode and the third signal readout device 530 is turned on. The response signal of the blue light output by the third signal readout device 530 is read on the column output line through the signal output unit 600. After the reading is completed, the signal output unit 600 is turned off.

[0099] When the bias voltage terminal 200 is forward-biased, that is, the direction of the bias voltage between the fixed terminal A and the first signal terminal B or the second signal terminal C is from the first signal terminal B or the second signal terminal C to the fixed terminal A. First, the first reset device 410 and the first switching device 710 are turned on to reset the first photodiode, the second photodiode, and the first charge storage device 810. Then, the first reset device 410 and the first switching device 710 are turned off. When the photoelectric conversion unit 10 is irradiated with light, if the light includes red light, the red light excites the second photodiode. Through the photoelectric effect, the second photodiode converts the optical signal into an electrical signal. The first reset device 410 is turned on to enable the first charge storage device 810 to release residual charges. Then, the first reset device 410 is turned off and the first switching device 710 is turned on, so that the charges corresponding to the electrical signal enter the first charge storage device 810 from the second photodiode and the second signal readout device 520 is turned on. The response signal of the red light output by the second signal readout device 520 is read on the column output line through the signal output unit 600. After the reading is completed, the signal output unit 600 is turned off.

[0100] Then, the second reset device 420 and the second switching device 720 are turned on to reset the third photodiode, the fourth photodiode, and the second charge storage device 820. Then, the second reset device 420 and the second switching device 720 are turned off. When the photoelectric conversion unit 10 is irradiated with light, if the light includes green light, the green light excites the third photodiode. Through the photoelectric effect, the third photodiode converts the optical signal into an electrical signal. The second reset device 420 is turned on to enable the second charge storage device 820 to release the residual charge. Then, the second reset device 420 is turned off and the second switching device 720 is turned on, so that the charge corresponding to the electrical signal enters the second charge storage device 820 from the third photodiode and the fourth signal reading device 540 is turned on. The response signal of the green light output by the fourth signal reading device 540 is read on the column output line through the signal output unit 600. After the reading is completed, the signal output unit 600 is turned off.

[0101] As another possible implementation, the response signals of different photodiodes 100 are output simultaneously. The signal output unit 600 includes a first signal output device 610 and a second signal output device 620. The signal reading unit 500 includes a first signal reading device 510, a second signal reading device 520, a third signal reading device 530, and a fourth signal reading device 540. The switching unit includes a first switching device 710 and a second switching device 720. The charge storage unit includes a first charge storage device 810 and a second charge storage device 820.

[0102] Reference Figure 13As shown, the bias voltage terminal 200 is connected to the first signal terminal B by means of the reset unit 400 and the first switching device 710, and the bias voltage terminal 200 is connected to the second signal terminal C by means of the reset unit 400 and the second switching device 720. The first signal terminal B is connected to the control terminals of the first signal reading device 510 and the second signal reading device 520 respectively by means of the first switching device 710, and the second signal terminal C is connected to the control terminals of the third signal reading device 530 and the fourth signal reading device 540 respectively by means of the second switching device 720. The control terminals of the first signal reading device 510 and the second signal reading device 520 are connected to one end of the first charge storage device 810, and the other end of the first charge storage device 810 is grounded. The control terminals of the third signal reading device 530 and the fourth signal reading device 540 are connected to one end of the second charge storage device 820, and the other end of the second charge storage device 820 is grounded. That is, the first signal reading device 510 and the second signal reading device 520 are respectively used to read the response signals output by the first photodiode and the second photodiode, and are also used to read the residual charge stored in the first charge storage device 810. The third signal reading device 530 and the fourth signal reading device 540 are respectively used to read the response signals of the fourth photodiode and the third photodiode, and are also used to read the residual charge stored in the second charge storage device 820. The second ends of the first signal reading device 510 and the second signal reading device 520 and the first signal output device 610 are connected. The second ends of the third signal reading device 530 and the fourth signal reading device 540 and the second signal output device 620 are connected. The two signal output devices respectively output the response signals of the two photodiodes in each anti-polarity channel, so that the response signals in different anti-polarity channels can be output simultaneously, greatly improving the detection efficiency.

[0103] As an example, when the bias voltage terminal 200 is negatively biased, that is, the direction of the bias voltage between the fixed terminal A and the first signal terminal B or the second signal terminal C is from the fixed terminal A to the first signal terminal B or the second signal terminal C. First, the reset unit 400, the first switching device 710, and the second switching device 720 are turned on to reset the first photodiode, the second photodiode, the third photodiode, the fourth photodiode, the first charge storage device 810, and the second charge storage device 820. Then, the reset unit 400, the first switching device 710, and the second switching device 720 are turned off. When the photoelectric conversion unit 10 is irradiated with light, if the light includes near-infrared light and blue light, the near-infrared light and blue light excite the first photodiode and the fourth photodiode. The first photodiode and the fourth photodiode convert the optical signal into an electrical signal through the photoelectric effect. The reset unit 400 is turned on to cause the first charge storage device 810 and the second charge storage device 820 to release the residual charge. Then, the reset unit 400 is turned off and the first switching device 710 and the second switching device 720 are turned on, so that the charge corresponding to the electrical signal enters the first charge storage device 810 from the first photodiode and the first signal reading device 510 is turned on, and the charge corresponding to the electrical signal enters the second charge storage device 820 from the fourth photodiode and the third signal reading device 530 is turned on. The response signal of the near-infrared light output by the first signal reading device 510 is read on the column output line 1 through the first signal output device 610, and the response signal of the blue light output by the third signal reading device 530 is read on the column output line 2 through the second signal output device 620. After the reading is completed, the first signal output device 610 and the second signal output device 620 are turned off.

[0104] When the bias voltage terminal 200 is forward-biased, that is, the direction of the bias voltage between the fixed terminal A and the first signal terminal B or the second signal terminal C is from the first signal terminal B or the second signal terminal C to the fixed terminal A. First, the reset unit 400, the first switching device 710, and the second switching device 720 are turned on to reset the first photodiode, the second photodiode, the third photodiode, the fourth photodiode, the first charge storage device 810, and the second charge storage device 820. Then, the reset unit 400, the first switching device 710, and the second switching device 720 are turned off. When the photoelectric conversion unit 10 is irradiated with light, if the light includes red light and green light, the red light and the green light excite the second photodiode and the third photodiode. The second photodiode and the third photodiode convert the optical signal into an electrical signal through the photoelectric effect. The reset unit 400 is turned on to cause the first charge storage device 810 and the second charge storage device 820 to release residual charges. Then, the reset unit 400 is turned off and the first switching device 710 and the second switching device 720 are turned on, so that the charges corresponding to the electrical signal enter the first charge storage device 810 from the second photodiode and the second signal readout device 520 is turned on, and the charges corresponding to the electrical signal enter the second charge storage device 820 from the third photodiode and the fourth signal readout device 540 is turned on. The response signal of the red light output by the second signal readout device 520 is read out on the column output line 1 through the first signal output device 610, and the response signal of the green light output by the fourth signal readout device 540 is read out on the column output line 2 through the second signal output device 620. After the reading is completed, the first signal output device 610 and the second signal output device 620 are turned off.

[0105] It can be seen that the present application provides a pixel circuit. The pixel circuit includes a photoelectric conversion unit and a signal readout unit. The photoelectric conversion unit includes a signal terminal, a fixed terminal, and a plurality of photodiodes located between the signal terminal and the fixed terminal. The signal terminal is electrically connected to a bias voltage, and the fixed terminal is grounded. In this way, the photodiode can be turned on by using the bias voltage between the signal terminal and the fixed terminal, so that the photodiode is reset to achieve spectral response. The signal readout unit includes a control terminal, a first terminal, and a second terminal. The control terminal is electrically connected to the signal terminal, the first terminal is electrically connected to a power supply voltage, and the light response signal of the photoelectric conversion unit is output through the second terminal. It can be seen that the pixel circuit of the present application can simply achieve spectral response and signal output through the photoelectric conversion unit and the signal readout unit, reduce the difficulty of signal processing, reduce the difficulty of imaging, and improve the imaging effect of color imaging.

[0106] Based on the pixel circuit provided in the above embodiments, the present application embodiments further provide an image sensor.

[0107] The image sensor provided by the embodiment of the present application includes a pixel array and a control circuit. The pixel array includes at least one pixel circuit as described in the above embodiment. The control circuit is electrically connected to the control terminals of the control devices in each pixel circuit to control the conduction or cutoff of the control devices in each pixel circuit. Specifically, the control devices may include a reset device of the reset unit, a switching device of the switching unit, and a signal output device of the signal output unit.

[0108] Based on the image sensor provided by the above embodiment, the embodiment of the present application further provides an electronic device. The electronic device provided by the embodiment of the present application includes the image sensor described in the above embodiment.

[0109] The above is only the preferred embodiment of the present application. Although the present application has been disclosed above with preferred embodiments, it is not intended to limit the present application. Any person skilled in the art can make many possible changes and modifications to the technical solution of the present application by using the methods and technical contents disclosed above, or modify it into an equivalent embodiment with equivalent changes. Therefore, any simple modification, equivalent change and modification made to the above embodiment according to the technical essence of the present application without departing from the content of the technical solution of the present application still fall within the scope of the protection of the technical solution of the present application.

Claims

1. A pixel circuit, characterized in that, The pixel circuit includes: A photoelectric conversion unit, which includes: a signal terminal, a fixed terminal, and a plurality of photodiodes located between the signal terminal and the fixed terminal; the signal terminal is electrically connected to a bias voltage, and the fixed terminal is grounded; A signal readout unit, which includes a control terminal, a first terminal, and a second terminal. The control terminal is electrically connected to the signal terminal, the first terminal is electrically connected to a power supply voltage, and the light response signal of the photoelectric conversion unit is output through the second terminal.

2. The pixel circuit according to claim 1, wherein The conduction directions of adjacent photodiodes are opposite.

3. The pixel circuit according to claim 1, wherein The response spectral range of each photodiode is different.

4. The pixel circuit according to claim 1, wherein The signal readout unit includes a plurality of signal readout devices, and the number of the signal readout devices is the same as the number of the photodiodes.

5. The pixel circuit according to claim 4, wherein The signal readout device includes a PMOS transistor and an NMOS transistor connected in series. The gates of the PMOS transistor and the NMOS transistor are both electrically connected to the signal terminal. The power supply voltage is electrically connected to one of the source or drain of the PMOS transistor and the source or drain of the NMOS transistor; the other of the source or drain of the PMOS transistor is electrically connected to the other of the source or drain of the NMOS transistor, and they jointly serve as the output terminal of the light response signal.

6. The pixel circuit according to any one of claims 1-5, characterized in that, The pixel circuit further includes: a reset unit, and the signal terminal is electrically connected to the bias voltage through the reset unit.

7. The pixel circuit according to claim 6, wherein The pixel circuit further includes: a switch unit, one end of the switch unit is electrically connected to the signal terminal, the other end of the switch unit is electrically connected to the reset unit, and is electrically connected to the control terminal of the signal readout unit.

8. The pixel circuit according to claim 7, wherein The pixel circuit further includes: a charge storage unit, one end of the charge storage unit is grounded, the other end of the charge storage unit is electrically connected to the switch unit, and is electrically connected to the control terminal of the signal readout unit.

9. The pixel circuit according to any one of claims 1-5, characterized in that, The pixel circuit further includes: a signal output unit, and the second terminal of the signal readout unit is electrically connected to a column output line through the signal output unit.

10. An image sensor, characterized in that, It includes a pixel array and a control circuit. The pixel array includes at least one pixel circuit according to any one of claims 1-9. The control circuit is electrically connected to the control terminals of the control devices in each pixel circuit to control the conduction or cut-off of the control devices in each pixel circuit.

11. An electronic device, characterized in that, It includes an image sensor according to claim 10.

Images