Pixel circuit, image sensor and electronic device

Abstract

The invention discloses a pixel circuit, an image sensor and electronic equipment, and belongs to the technical field of camera equipment. The pixel circuit comprises a photosensitive module, a roller shutter control module and a global shutter control module, the photosensitive module is used for outputting a first photoelectric signal; the roller shutter control module is used for converting the first photoelectric signal into a second photoelectric signal and outputting the second photoelectric signal through a first output line and a first output end; the global shutter control module is electrically connected with the first output end of the rolling shutter control module, the control voltage end of the global shutter control module and a second output line, and the global shutter control module is used for converting the second photoelectric signal into a third photoelectric signal under the control of the control voltage output by the control voltage end; and a third photoelectric signal is output through a second output line.

Description

Technical Field

[0001] This application belongs to the technical field of imaging devices, and particularly relates to a pixel circuit, an image sensor, and an electronic device. Background Art

[0002] A "shutter" is a component that controls the exposure time. According to its structural characteristics, shutters include: mechanical shutters and electronic shutters. Electronic shutters include: progressive scan electronic shutters and global electronic shutters, namely rolling shutters and global shutters.

[0003] In related technologies, most of the pixel exposure methods used in image sensors of electronic devices are progressive scan rolling shutters. However, due to the time difference in exposure between pixel rows in this exposure method, jello or distortion effects will occur on high-speed moving objects in the output picture. Summary of the Invention

[0004] The purpose of the embodiments of this application is to provide a pixel circuit, an image sensor, and an electronic device, which can enable pixel units to support both rolling exposure and global exposure mode selections, and can implement selecting the global exposure mode for the area of the image sensor where the moving object is located to obtain a true image of the moving object and avoid the occurrence of the jello effect; selecting the progressive exposure mode for other areas of the image sensor to obtain a better signal-to-noise ratio.

[0005] To solve the above technical problems, this application is implemented as follows:

[0006] In a first aspect, the embodiments of this application provide a pixel circuit, including a photosensitive module, a rolling shutter control module, and a global shutter control module;

[0007] The photosensitive module is used to output a first optoelectronic signal;

[0008] [[ID=~28]]The rolling shutter control module is used to convert the first optoelectronic signal into a second optoelectronic signal and output the second optoelectronic signal through a first output line and a first output terminal;

[0009] The global shutter control module is electrically connected to the first output terminal of the rolling shutter control module, the control voltage terminal of the global shutter control module, and a second output line respectively. The global shutter control module is used to convert the second optoelectronic signal into a third optoelectronic signal under the control of the control voltage output at the control voltage terminal, and output the third optoelectronic signal through the second output line.

[0010] In a second aspect, the embodiments of this application provide an image sensor, including the pixel circuit as described in the first aspect.

[0011] In a third aspect, an embodiment of the present application provides an electronic device, including a signal processing module and an image sensor as described in the second aspect;

[0012] The signal processing module is connected to the image sensor, and the signal processing module is configured to process the output signal of the image sensor.

[0013] In an embodiment of the present application, the pixel circuit includes a photosensitive module, a rolling shutter control module, and a global shutter control module; the photosensitive module is configured to output a first optoelectronic signal; the rolling shutter control module is configured to convert the first optoelectronic signal into a second optoelectronic signal and output the second optoelectronic signal through a first output line and a first output terminal; the global shutter control module is electrically connected to the first output terminal of the rolling shutter control module, the control voltage terminal of the global shutter control module, and a second output line respectively, and the global shutter control module is configured to convert the second optoelectronic signal into a third optoelectronic signal under the control of a control voltage output at the control voltage terminal and output the third optoelectronic signal through the second output line. This embodiment enables each pixel unit corresponding to the photosensitive module to have two mode selections of rolling exposure and global exposure at the same time. When the photosensitive module adopts a progressive exposure form, the second optoelectronic signal output by the first output line is obtained. When the photosensitive module adopts a global exposure form, the third optoelectronic signal output by the second output line is obtained. Based on this embodiment, the exposure mode can be selected according to actual needs during photographing to more quickly and accurately capture the image of a moving object and avoid the occurrence of the jelly effect. For example, the global exposure mode can be selected for the area of the image sensor where the moving object is located to obtain the real image of the moving object and avoid the occurrence of the jelly effect; the progressive exposure mode can be selected for other areas of the image sensor to obtain a better signal-to-noise ratio. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 A schematic structural diagram of a pixel circuit provided by some embodiments of the present invention;

[0015] Figure 2 A schematic cross-sectional view of a lens module provided by some embodiments of the present invention;

[0016] Figure 3 A schematic diagram showing a first physical arrangement of pixels provided by some embodiments of the present invention;

[0017] Figure 4 A schematic diagram showing a second physical arrangement of pixels provided by some embodiments of the present invention;

[0018] Figure 5 A schematic diagram showing a third physical arrangement of pixels provided by some embodiments of the present invention;

[0019] Figure 6 A schematic diagram showing a progressive exposure process provided by some embodiments of the present invention;

[0020] Figure 7 Schematic diagram of the global exposure process provided by some embodiments of the present invention;

[0021] Figure 8 Schematic diagram showing the combination of line-by-line exposure and global exposure provided by some embodiments of the present invention. Detailed implementation manners

[0022] Next, the technical solutions in the embodiments of the present application will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are some, but not all, of the embodiments of the present application. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present application without creative efforts shall fall within the scope of protection of the present application.

[0023] The terms "first", "second", etc. in the description and claims of the present application are used to distinguish similar objects, rather than to describe a specific order or sequence. It should be understood that such data can be interchanged under appropriate circumstances so that the embodiments of the present application can be implemented in an order different from those illustrated or described herein. In addition, "and / or" in the description and claims means at least one of the connected objects, and the character " / " generally means an "or" relationship between the associated objects before and after.

[0024] The terms used in the implementation manners part of the present application are only used to explain the specific embodiments of the present application, rather than to limit the present application. The terms related to the embodiments of the present application are explained below. The three elements of exposure include aperture, shutter, and sensitivity. Among them, the aperture is used to control the amount of light entering the camera and can be understood as the human eye, which is represented by F on the camera. The shutter is a device used to control the length of the light exposure time of the camera and is represented by seconds (s). Different exposure times result in different photo effects. The sensitivity is a measure of the sensitivity of the photosensitive element to light, abbreviated as ISO, and the brightness value of the picture can be set before shooting.

[0025] The parameters for evaluating a camera include image quality. The factors affecting image quality include signal-to-noise ratio and resolution. Whether the signal-to-noise ratio is too low or the resolution is too low, a satisfactory picture cannot be obtained.

[0026] The signal-to-noise ratio, also known as SNR or S / N (SIGNAL-NOISE RATIO), is the ratio of the power of the output signal of an amplifier to the power of the noise output simultaneously, and is usually expressed in decibels. The higher the signal-to-noise ratio of a device, the less noise it generates. Generally speaking, the larger the signal-to-noise ratio, the smaller the noise mixed in the signal, and the higher the audio quality of the sound playback, otherwise it is the opposite.

[0027] The shutter is a component that controls the exposure time. Shutter can also be classified in various ways according to its structural characteristics. Common shutters include: mechanical shutter and electronic shutter. Mechanical shutter includes focal plane shutter and between-lens shutter. Electronic shutter includes progressive scan electronic shutter and global electronic shutter. Among them, the progressive scan electronic shutter is also called rolling shutter, and the global electronic shutter is also called global shutter.

[0028] Currently, the camera functions of electronic devices are becoming more and more diverse, and at the same time, consumers' requirements for the camera experience of electronic devices are also getting higher and higher, which poses higher requirements for the camera functions, performance and effects of electronic devices. Most cameras in electronic devices use progressive scan electronic shutters, and this type of shutter has the jello effect.

[0029] Optical image stabilization corrects the "optical axis shift" through the floating lens of the lens. Its principle is that the gyroscope inside the lens detects a small movement, then transmits the signal to the microprocessor. The microprocessor immediately calculates the displacement amount that needs to be compensated, and then compensates through the compensating lens group according to the shaking direction and displacement amount of the lens; thus effectively overcoming the image blurring caused by the vibration of the camera.

[0030] Optical image stabilization can be understood as only increasing the safe shutter speed to increase the light intake of the lens. Ultimately, the image sensor and the lens determine the image quality. If there is no optical image stabilization, other methods can also be used to increase the safe shutter speed to increase the light intake of the lens. For example, using an external tripod, or manually adjusting the ISO value from the software. Many manufacturers have even adjusted the preset parameters of mobile phone cameras, sacrificing the overall image quality after imaging in a certain environment to improve the visual effect of photos on the mobile phone.

[0031] It should be noted that the camera effect of electronic devices is relatively poor at night. One of the reasons is that the pixel size of the image sensor is too small, resulting in less light energy that can be collected by the pixels in a low-light environment. When the backend processes the optical signal transformation, a lot of noise will be introduced, which leads to very poor final image quality. If the anti-shake function is well implemented, it can extend the exposure time when the image sensor takes pictures. Longer exposure time is very helpful for the signal-to-noise ratio and image quality of the image, especially for the image effect in a night scene environment.

[0032] Optical Image Stabilization (OIS) can increase the exposure time, but the prerequisite is that it can return to the center for each frame. However, OIS controls the lens to return to the center only during the non-exposure period of the image sensor to prepare for the anti-shake of the next frame of image. And currently, most image sensors use rolling shutter, and the rolling shutter method leaves very little time for OIS to move the lens, resulting in that OIS actually cannot bring more exposure time.

[0033] A larger pixel size means that a CIS sensor with 50M pixels will have a larger sensor area. Image sensors with a larger sensor area are more costly and take up more space.

[0034] Based on the above, there is an urgent need to provide a pixel circuit and an image sensor that support both rolling shutter and global shutter modes. For the area of the image sensor where moving objects are located, the global shutter mode can be selected to obtain a true image of the moving object. For the area of the image sensor where non-moving objects are located, the rolling shutter mode can be selected to obtain a better signal-to-noise ratio. By selecting the exposure mode according to actual needs, it is ensured that when the camera is moving or there are moving objects in the frame, the image sensor can capture the images of the moving objects more quickly and accurately, avoiding the jelly effect and ultimately improving the user experience.

[0035] The following will, with reference to the accompanying drawings, elaborate on the control method provided by the embodiments of the present application through specific embodiments and their application scenarios.

[0036] Please refer to Figure 1 , an embodiment of the present invention provides a pixel circuit, including: a photosensitive module 1, a rolling shutter control module 2, and a global shutter control module 3;

[0037] The photosensitive module 1 is configured to output a first optoelectronic signal;

[0038] The rolling shutter control module 2 is configured to convert the first optoelectronic signal into a second optoelectronic signal and output the second optoelectronic signal through a first output line sig1 and a first output terminal out1;

[0039] The global shutter control module 3 is electrically connected to the first output terminal out1 of the rolling shutter control module 2, the control voltage terminal of the global shutter control module 3, and a second output line sig2 respectively. The global shutter control module √ is configured to convert the second optoelectronic signal into a third optoelectronic signal under the control of a control voltage output by the control voltage terminal and output the third optoelectronic signal through the second output line sig2.

[0040] Wherein, each photosensitive module 1 corresponds to a pixel unit R, Gr, Gb, or B, and each pixel unit corresponds to a pixel circuit as shown in Figure 1 , enabling each photosensitive module 1 to independently select an exposure method.

[0041] It should be noted that, compared with the rolling shutter control module 2, the global shutter control module 3 has the function of latching optoelectronic signals for a long time and can wait for reading for a sufficient time.

[0042] As shown in Figure 6 , it shows a schematic diagram of the rolling shutter exposure process. Figure 6Each row of pixels in it needs to be exposed and read completely before the exposure and reading of the next row of pixels can be carried out, because the optoelectronic signals in the rolling shutter control module 2 cannot be stored for a long time, and the pixel voltage must be read out immediately after the pixel is exposed. For example, the exposure start time of the first row of pixels is 0 us, the exposure start time of the second row of pixels is 10.16 us, the exposure start time of the third row of pixels is 20.32 us, and so on. The start exposure time of the last row of pixels is 71.12 us. That is to say, the second pixel row will have a later exposure time than the first pixel row, and similarly, the third pixel row will have a later exposure time than the second pixel row, and so on. The last row of pixels has the latest exposure. This exposure method will cause image smear and distortion when shooting moving objects.

[0043] As Figure 7 shown, it shows a schematic diagram of the global exposure process. Figure 7 All pixels in it can be exposed simultaneously, and then each pixel unit stores the optoelectronic signal in its respective global shutter control module 3. The global shutter control module 3 has the function of long-term latching of optoelectronic signals and can wait to be read out by the readout circuit at any time. The global exposure method can ensure that each row of pixels senses the scene simultaneously, greatly reducing the smear and distortion phenomena.

[0044] In the embodiments of the present application, when the pixel units in the pixel array are selected for row-by-row exposure, the second optoelectronic signal output by the pixel circuit of the pixel is read from the first output line sig1; when the pixel units in the pixel array are selected for global exposure, the third optoelectronic signal output by the pixel circuit in each pixel row is read sequentially from the second output line sig2. In this way, it is possible to enable the pixel units corresponding to each photosensitive module 1 to have two mode selections of rolling exposure and global exposure at the same time.

[0045] Based on the pixel circuit provided by the embodiments of the present application, in specific applications, the global exposure mode can be selected for the image sensor area where the moving object is located to obtain a real image of the moving object; the row-by-row exposure mode can be selected for other areas of the image sensor to obtain a better signal-to-noise ratio. For example, in some exemplary scenarios, when a user needs to take a photo of a running athlete, the global exposure mode can be selected for the image sensor area where the athlete is located, and the row-by-row exposure mode can be selected for other static image areas of the image sensor.

[0046] Through the pixel circuit provided by the embodiments of the present application, the user can select the exposure mode according to actual needs, which enables the image sensor to capture the shape of the moving object more quickly and accurately in the case of camera movement or when there are moving objects in the picture, avoiding the jelly effect and ultimately improving the user experience.

[0047] As Figure 8As shown, it shows a schematic diagram of a hybrid exposure method with 8 rows of pixels. Figure 8 Among them, the first four rows of pixel arrays select the global exposure mode. After all 8 rows of pixels are exposed, the second optoelectronic signals corresponding to each row of pixels are sequentially read through the second output line sig2 corresponding to each pixel unit. Figure 8 Among them, the last four rows of pixel arrays select the row-by-row exposure mode. After each row of pixels is exposed, the second optoelectronic signals corresponding to each row of pixels are sequentially read through the first output line sig1 corresponding to each pixel unit.

[0048] It should be noted that Figure 8 Within the L1 and L3 intervals in , the camera cannot move, and within the L2 interval, the camera can move. Compared with traditional pixels, optical image stabilization OIS can be achieved, and the camera position can also be adjusted during exposure.

[0049] In some embodiments of the present application, the photosensitive module 1 is electrically connected to the first control terminal TG and the optoelectronic signal output terminal out0 respectively, and is used to convert the received optical signal into a first optoelectronic signal, and under the control of the first control signal output by the first control terminal TG, output the first optoelectronic signal through the optoelectronic signal output terminal out0.

[0050] In this embodiment, after the photosensitive module is exposed, the photosensitive module converts the received optical signal into a first optoelectronic signal, and through the first control signal output by the first control terminal TG, outputs the first optoelectronic signal from the optoelectronic signal output terminal out0 to the rolling shutter control module 2.

[0051] In some embodiments, the photosensitive module 1 includes a photodiode PD and a fourth transistor m4;

[0052] The anode of the photodiode PD is electrically connected to the second voltage terminal, and the cathode of the photodiode PD is electrically connected to the first pole of the fourth transistor m4;

[0053] The control pole of the fourth transistor m4 is electrically connected to the first control terminal TG, and the second pole of the fourth transistor m4 is electrically connected to the optoelectronic signal output terminal out0.

[0054] See Figure 1 , the second voltage terminal is a ground terminal. Each photosensitive module 1 is correspondingly provided with a pixel circuit as shown in Figure 1 . Each photosensitive module 1 corresponds to a pixel unit, and the pixel unit can be pixel R, pixel Gr, pixel Gb or pixel B. Through this embodiment, it is possible to realize that each pixel unit can independently select an exposure method.

[0055] In some embodiments of the present application, the control voltage terminal includes a first control voltage terminal Hold and a second control voltage terminal G_SET;

[0056] The global shutter control module 3 is electrically connected to the first node n1. The global shutter control module 3 is configured to convert a second optoelectronic signal into a fourth optoelectronic signal under the control of a first control voltage output by the first control voltage terminal Hold, transmit the fourth optoelectronic signal to the first node n1, and maintain the potential of the first node n1; and convert the fourth optoelectronic signal into a third optoelectronic signal under the control of a second control voltage output by the second control voltage terminal G_SET, and output the third optoelectronic signal through the second output line sig2.

[0057] In this embodiment, the first control voltage output by the first control voltage terminal Hold can be used to activate the global shutter control module 3, and transmit the second optoelectronic signal output by the first output terminal out1 of the rolling shutter control module 2 to the global shutter control module 3, so as to realize the long-time storage of the optoelectronic signal and meet the read time requirement of global exposure. When reading is required, under the control of the second control voltage output by the second control voltage terminal G_SET, the third optoelectronic signal output by the second output line sig2 is obtained to realize the function of the global shutter.

[0058] In some embodiments of the present application, the global shutter control module 3 includes: a sample and hold module 31 and a first signal output module 32;

[0059] The sample and hold module 31 is electrically connected to the first output terminal out1, the first control voltage terminal Hold, and the first node n1 respectively. The sample and hold module 31 is configured to convert a second optoelectronic signal into a fourth optoelectronic signal under the control of the first control voltage, output the fourth optoelectronic signal to the first node n1, and maintain the potential of the first node n1;

[0060] The first signal output module 32 is electrically connected to the first node n1, the second control voltage terminal G_SET, and the second output line sig2 respectively. The first signal output module 32 is configured to convert the fourth optoelectronic signal into a third optoelectronic signal under the control of the second control voltage, and output the third optoelectronic signal through the second output line gis2.

[0061] In this embodiment, under the control of the first control voltage output by the first control voltage terminal Hold, the sample and hold module 31 converts the second optoelectronic signal output by the rolling shutter control module 2 into a fourth optoelectronic signal, transmits the fourth optoelectronic signal to the first node n1, and maintains the potential of the first node n1 to realize the long-time optoelectronic signal locking function; when reading is required, under the control of the second control voltage output by the second control voltage terminal G_SET, the fourth optoelectronic signal is converted into a third optoelectronic signal, and the third optoelectronic signal is output through the second output line gis2.

[0062] In some embodiments of the present application, the sample and hold module 31 includes: a first operational amplifier A1, a first energy storage module 311, and a first on-off control module 312;

[0063] The input terminal of the first operational amplifier A1 is connected to the first output terminal out1, and the output terminal of the first operational amplifier A1 is electrically connected to the first end of the first on-off control module 312. The first operational amplifier A1 is configured to convert the second optoelectronic signal into a fourth optoelectronic signal;

[0064] The first on-off control module 312 is electrically connected to the first control voltage terminal Hold, and the second end of the first on-off control module 312 is electrically connected to the first node n1. The first on-off control module 312 is configured to output the fourth optoelectronic signal to the first node n1 under the control of the first control voltage;

[0065] The first energy storage module 311 is configured to maintain the potential of the first node n1.

[0066] In this embodiment, the first on-off control module 312 is configured to control whether to activate the global shutter control module 3. Under the control of the first control voltage, the first on-off control module 312 activates the global shutter control module 3, and uses the single-way conduction function of the first operational amplifier A1 to lock the fourth optoelectronic signal in the first energy storage module 311 for a long time.

[0067] In some embodiments of the present application, the first energy storage module 311 includes a first capacitor c1, and the first on-off control module 312 includes a first transistor m1;

[0068] The first end of the first capacitor c1 is electrically connected to the first node n1, and the second end of the first capacitor c1 is electrically connected to the second voltage terminal;

[0069] The control electrode of the first transistor m1 is electrically connected to the first control voltage terminal Hold, the first pole of the first transistor m1 is electrically connected to the output terminal of the first operational amplifier A1, and the second pole of the first transistor m1 is electrically connected to the first node n1.

[0070] Optionally, the second voltage terminal is a ground terminal.

[0071] In this embodiment, under the control of the first control voltage output by the first control voltage terminal Hold, the first transistor m1 is activated, and the second optoelectronic signal is amplified by the first operational amplifier A1 and then injected into the first capacitor c1 for storage.

[0072] In at least some embodiments of the present application, when each transistor is a thin film transistor or a MOS (metal-oxide-semiconductor) transistor, the control electrode is the gate, the first pole is the source, and the second pole is the drain, or the control electrode is the gate, the first pole is the drain, and the second pole is the source;

[0073] When each transistor is a triode, the control electrode is the base, the first electrode is the emitter, and the second electrode is the collector. Alternatively, the control electrode is the base, the first electrode is the collector, and the second electrode is the emitter.

[0074] In some embodiments of the present application, the first signal output module 32 includes a second operational amplifier A2, a first conversion module 321, and a second on-off control module 322;

[0075] The second operational amplifier A2 is configured to convert the fourth optoelectronic signal into a fifth optoelectronic signal and output the fifth optoelectronic signal to the first conversion module 321;

[0076] The first conversion module 321 is configured to convert the fifth optoelectronic signal into a third optoelectronic signal;

[0077] The second on-off control module 322 is electrically connected to the second control voltage terminal G_SET, the first conversion module 321, and the second output line sig2, and is configured to transmit the third optoelectronic signal to the second output line sig2 under the control of the second control voltage.

[0078] In this embodiment, when it is necessary to read the optoelectronic signal after the exposure is completed, under the control of the second control voltage output from the second control voltage terminal G_SET, the fourth optoelectronic signal is converted into a fifth optoelectronic signal by the second operational amplifier A2 and output to the first conversion module 321; further, the fifth optoelectronic signal is converted into a third optoelectronic signal by the first conversion module 321, and finally the third optoelectronic signal is transmitted to the second output line sig2 for reading.

[0079] In some embodiments of the present application, the first conversion module 321 includes a second transistor m2, and the second on-off control module includes a third transistor m3;

[0080] The control electrode of the second transistor m2 is electrically connected to the output terminal of the second operational amplifier A2, the first electrode of the second transistor m2 is electrically connected to the power supply voltage terminal, and the second electrode of the second transistor m2 is electrically connected to the first electrode of the third transistor m3;

[0081] The control electrode of the third transistor m3 is electrically connected to the second control voltage terminal G_SET, and the second electrode of the third transistor m3 is electrically connected to the second output line sig2.

[0082] Optionally, the power supply voltage terminal is VDD in the figure.

[0083] In this embodiment, when reading the optoelectronic signal in the second output line sig2, under the control of the second control voltage output from the second control voltage terminal G_SET, the fourth optoelectronic signal output from the first energy storage module 311 is converted into a third optoelectronic signal through the second operational amplifier A2 and the second transistor m2, and is output to the second output line sig2 through the second pole of the third transistor m3 for reading.

[0084] In some embodiments of the present application, the rolling shutter control module 2 is electrically connected to the second control terminal R_SET, the optoelectronic signal output terminal out0, the first output terminal out1, and the first output line sig1 respectively, and is used to maintain the potential of the optoelectronic signal output terminal out0, and convert the first optoelectronic signal into a second optoelectronic signal under the control of the second control signal output from the second control terminal R_SET, and output the second optoelectronic signal through the first output terminal out1 and the first output line sig1.

[0085] In this embodiment, the rolling shutter control module 2 is activated by the second control signal output from the second control terminal R_SET, converts the stored first optoelectronic signal into a second optoelectronic signal, and outputs it through the first output terminal out1 and the first output line sig1.

[0086] In some embodiments of the present application, the rolling shutter control module 2 includes a second energy storage module 21 and a second signal output module 22;

[0087] The first end of the second energy storage module 21 is electrically connected to the optoelectronic signal output terminal out0, the second end of the second energy storage module 21 is electrically connected to the second voltage terminal, and the second energy storage module 21 is used to maintain the potential of the optoelectronic signal output terminal out;

[0088] The second signal output module 22 is electrically connected to the first output terminal out1, the first output line sig1, and the first end of the second energy storage module 21, and is used to convert the first optoelectronic signal into a second optoelectronic signal under the control of the second control signal output from the second control terminal R_SET, and output the second optoelectronic signal through the first output terminal out1 and the first output line sig1.

[0089] As Figure 1 In, the second voltage terminal is a ground terminal; the second energy storage module 21 includes a second capacitor c2, and the second signal output module 22 includes a fifth transistor m5 and a sixth transistor m6;

[0090] The control electrode of the fifth transistor m5 is electrically connected to the optoelectronic signal output terminal out0 and the first end of the second capacitor c2 respectively, the first pole of the fifth transistor m5 is electrically connected to the power supply voltage terminal, and the second pole of the fifth transistor m5 is electrically connected to the first output terminal ou1; the second end of the second capacitor c2 is electrically connected to the second voltage terminal;

[0091] The control electrode of the sixth transistor M6 is electrically connected to the second control terminal R_SET, the first electrode of the sixth transistor M6 is electrically connected to the first output terminal OUT1, and the second electrode of the sixth transistor M6 is electrically connected to the first output line SIG1.

[0092] See Figure 1 , before starting exposure, first activate the seventh transistor M7 to completely transfer the charge from the photodiode PD to the second capacitor C2 for reading. The mechanism here is similar to the charge transfer in a CCD. At this time, the voltage of the second capacitor C2 drops due to the charge injection from the PD; then, through the second control signal output by the second control terminal R_SET, activate the sixth transistor M6 to transmit the first photoelectric signal in the second capacitor C2 to the fifth transistor M5 for amplification to obtain a second photoelectric signal, and output it to the first output terminal OUT1 through the second electrode of the fifth transistor M5, and transmit it to the first output line SIG1 through the second electrode of the sixth transistor M6.

[0093] In some embodiments of the present application, the rolling shutter control module 2 further includes a reset module 23;

[0094] The reset module 23 is respectively electrically connected to the third control terminal RST, the first voltage terminal, the first end of the second energy storage module 21, and the photoelectric signal output terminal OUT0, and is used to control the first voltage terminal to be respectively connected to the photoelectric signal output terminal OUT0 and the first end of the second energy storage module 21 under the control of the third control signal output by the third control terminal RST.

[0095] In this embodiment, the reset module 23 is used to empty the charges in the rolling shutter control module 2 and the photosensitive module 1.

[0096] As Figure 1 In, the first voltage terminal is VDD; the reset module 23 includes a seventh transistor M7; the gate of the seventh transistor M7 is electrically connected to the third control terminal RST, the first electrode of the seventh transistor M7 is electrically connected to the first voltage terminal, and the second electrode of the seventh transistor M7 is electrically connected to the photoelectric signal output terminal OUT0.

[0097] Before pixel exposure, under the control of the third control signal output by the third control terminal RST, the seventh transistor M7 is turned on to connect the photosensitive module 1 to the first voltage terminal, the first end of the second capacitor C2 is connected to the first voltage terminal, and a path is formed between the first voltage terminal and the second voltage terminal. The second voltage terminal is a ground terminal to empty the charges in the photodiode PD and the second capacitor C2.

[0098] Next, in conjunction with the pixel circuit as Figure 1 shown, the operation process of pixel exposure will be described.

[0099] Step 1: Pixel exposure.

[0100] Before pixel exposure, turn on the seventh transistor m7, the fourth transistor m4, and the first transistor m1 simultaneously to empty the charges in the photodiode PD, the second capacitor c2, and the first capacitor c1. After emptying, turn off the seventh transistor m7, the fourth transistor m4, and the first transistor m1, and start the exposure. The electron-hole pairs generated by light irradiation will be separated due to the existence of the PD electric field. The electrons move to the n region, and the holes move to the p region.

[0101] Step 2: Charge transfer.

[0102] It should be noted that the operations in this step are different for different exposure modes.

[0103] (1) For the line-by-line exposure mode.

[0104] If line-by-line exposure output is selected, first activate the fourth transistor m4 through the first control signal output by the first control terminal TG to completely transfer the charges from the photodiode PD to the second capacitor c2 for reading. The mechanism here is similar to the charge transfer in a Charge-Coupled Device (CCD). At this time, the voltage of the second capacitor c2 drops due to the charge injection from the PD. Then, activate the sixth transistor m6 through the second control signal output by the second control terminal R_SET to transfer the first optical signal stored in the second capacitor c2 to the fifth transistor m5 for amplification to obtain the second optical signal, and select and output the second optical signal through the sixth transistor m6.

[0105] (2) For the global exposure mode

[0106] If global exposure output is selected, first activate the fourth transistor m4 through the first control signal output by the first control terminal TG to completely transfer the charges from the photodiode PD to the second capacitor c2 for reading. The mechanism here is similar to the charge transfer in a Charge-Coupled Device (CCD). At this time, the voltage of the second capacitor c2 drops due to the charge injection from the PD. Then, keep the sixth transistor m6 off and activate the first transistor m1 through the first control voltage output by the first control voltage terminal Hold. The first optical signal of the second capacitor c2 is injected into the first capacitor c1 after passing through the fifth transistor m5 and the first operational amplifier A1 in sequence. The first capacitor c1 can store the optical signal for a long time, so it can be read out not immediately after exposure. When reading is required, activate the third transistor m3 by outputting the second control voltage through the second control voltage terminal G_SET to realize the output of the optical signal.

[0107] It should be noted that, Figure 1DC1 and DC2 therein are the first DC power supply and the second DC power supply respectively, and are used to supply power to the pixel circuit.

[0108] An embodiment of the present application further provides an image sensor, including the pixel circuit as described above.

[0109] As Figure 2 shown, it shows a camera module. The lens assembly 41 in the camera module is used for light collection and focusing. The lens assembly 41 is wrapped and fixed by the voice coil motor 42. The upper and lower ends of the voice coil motor 42 are connected to the elastic pieces on the base 43. During focusing, by energizing the voice coil motor 42 to generate an electromagnetic force, this force finally balances with the elastic force of the elastic piece. The position of the voice coil motor 42 can be controlled by the magnitude of the energization. Based on this principle, after determining the appropriate focus point according to the phase signal, the lens assembly 41 is pushed to the appropriate focusing position by the voice coil motor 42.

[0110] It should be noted that the scene light converging into the camera module is projected onto the infrared filter. The function of the infrared filter is to filter out unnecessary light projected onto the image sensor 44, prevent the image sensor 44 from generating false colors / ripples, so as to improve its effective resolution and color reducibility. The light passing through the infrared filter can be sensed by the image sensor 43; after the light reaches the image sensor 44, it enters the pixel area through the microlens and the color filter 45. Among them, the camera module also includes electronic components 46.

[0111] It should be noted that the image sensor in the camera module can be a Bayer sensor. Exemplarily, the physical arrangement of the Bayer sensor can be as Figures 3 to 5 shown. Each pixel unit R, Gr, Gb or B in the figure corresponds to an independent pixel circuit respectively, so as to realize that each pixel unit can support two mode selections of rolling exposure and global exposure.

[0112] Moreover, the pixel circuit in the embodiment of the present application can also realize the global exposure of a local area of the image sensor, so that the global exposure of the local area and the progressive exposure are combined and used, and each has the advantages of the two modes.

[0113] It should be noted that for an object moving at high speed, since each row of pixels in the image is at different time points on the time axis, there will be differences between the images of adjacent rows. In a fast-moving scene, progressive exposure cannot truly restore the actual scene in principle, resulting in deformation or tomography of the moving object. Based on the image sensor provided in the embodiments of the present application, for the area of the image sensor where the moving object is located, the global exposure mode can be selected to obtain a real image of the moving object; for other areas of the image sensor, progressive exposure can be selected to obtain a better signal-to-noise ratio. In this way, based on the image sensor provided in the embodiments of the present application, the user can select the exposure mode according to actual needs, which enables the image sensor to capture the shape of the moving object more quickly and accurately in the case of camera movement or when there is a moving object in the frame, avoiding the jelly effect and ultimately enhancing the user experience.

[0114] The embodiments of the present application further provide an electronic device, including a signal processing module and the image sensor as described above; the signal processing module is connected to the image sensor, and the signal processing module is used to process the output signal of the image sensor.

[0115] In some embodiments of the present application, the signal processing module is connected to the image sensor through a first output line sig1 and a second output line sig2;

[0116] Among them, the signal processing module obtains a second optoelectronic signal through the first output line sig1; alternatively, the signal processing module obtains a third optoelectronic signal through the second output line sig2.

[0117] In the case of selecting progressive exposure, the second optoelectronic signals output from the first output line sig1 in each pixel circuit located in the same pixel row are sequentially read; in the case of selecting global exposure, the third optoelectronic signal output from each pixel circuit is read from the second output line sig2 in the corresponding pixel circuit.

[0118] Further, after the read second optoelectronic signal / third optoelectronic signal is subjected to analog-to-digital conversion (ADC), the analog signal is converted into a digital signal and an image signal is formed; after the image signal is subjected to image enhancement processing by an image signal processor (ISP), it is transmitted to a backend application processor (AP) through a mobile industry processor interface (MIPI).

[0119] It should be noted that in this text, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, such that a process, method, article or device comprising a series of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article or device. Without further limitation, an element defined by the statement "comprising one..." does not exclude the presence of additional identical elements in the process, method, article or device comprising that element. In addition, it should be pointed out that the scope of the methods and devices in the embodiments of the present application is not limited to performing functions in the order shown or discussed, and may also include performing functions in a substantially simultaneous manner or in the reverse order according to the functions involved. For example, the described methods may be performed in an order different from that described, and various steps may be added, omitted, or combined. Additionally, the features described with reference to certain examples may be combined in other examples.

[0120] The embodiments of the present application have been described above in conjunction with the accompanying drawings. However, the present application is not limited to the above specific embodiments. The above specific embodiments are merely illustrative and not restrictive. Under the inspiration of the present application, those of ordinary skill in the art can also make many forms without departing from the purpose of the present application and the scope protected by the claims, and all of them fall within the protection scope of the present application.

Claims

1. A pixel circuit, characterized in that, It includes a photosensitive module, a rolling shutter control module, and a global shutter control module; The photosensitive module is used to output a first optoelectronic signal; The rolling shutter control module is used to convert the first optoelectronic signal into a second optoelectronic signal, and output the second optoelectronic signal through a first output line and a first output terminal; The global shutter control module is electrically connected to the first output terminal of the rolling shutter control module, the control voltage terminal of the global shutter control module, and a second output line respectively. The global shutter control module is used to convert the second optoelectronic signal into a third optoelectronic signal under the control of a control voltage output by the control voltage terminal, and output the third optoelectronic signal through the second output line.

2. The pixel circuit according to claim 1, wherein The control voltage terminal includes a first control voltage terminal and a second control voltage terminal; The global shutter control module is electrically connected to a first node. The global shutter control module is used to convert the second optoelectronic signal into a fourth optoelectronic signal under the control of a first control voltage output by the first control voltage terminal, transmit the fourth optoelectronic signal to the first node, and maintain the potential of the first node; And under the control of a second control voltage output by the second control voltage terminal, convert the fourth optoelectronic signal into a third optoelectronic signal, and output the third optoelectronic signal through the second output line.

3. The pixel circuit according to claim 2, wherein, The global shutter control module includes: a sample-and-hold module and a first signal output module; The sample-and-hold module is electrically connected to the first output terminal, the first control voltage terminal, and the first node respectively. The sample-and-hold module is used to convert the second optoelectronic signal into a fourth optoelectronic signal under the control of the first control voltage, output the fourth optoelectronic signal to the first node, and maintain the potential of the first node; The first signal output module is electrically connected to the first node, the second control voltage terminal, and the second output line respectively. The first signal output module is used to convert the fourth optoelectronic signal into a third optoelectronic signal under the control of the second control voltage, and output the third optoelectronic signal through the second output line.

4. The pixel circuit according to claim 3, wherein The sample-and-hold module includes: a first operational amplifier, a first energy storage module, and a first on-off control module; The input terminal of the first operational amplifier is connected to the first output terminal, and the output terminal of the first operational amplifier is electrically connected to the first end of the first on-off control module. The first operational amplifier is used to convert the second optoelectronic signal into a fourth optoelectronic signal; The first on-off control module is electrically connected to the first control voltage terminal, and the second end of the first on-off control module is electrically connected to the first node. The first on-off control module is used to output the fourth optoelectronic signal to the first node under the control of the first control voltage; The first energy storage module is used to maintain the potential of the first node.

5. The pixel circuit according to claim 4, characterized in that, The first energy storage module includes a first capacitor, and the first on-off control module includes a first transistor; The first end of the first capacitor is electrically connected to the first node, and the second end of the first capacitor is electrically connected to a second voltage terminal; The control electrode of the first transistor is electrically connected to the first control voltage terminal, the first electrode of the first transistor is electrically connected to the output terminal of the first operational amplifier, and the second electrode of the first transistor is electrically connected to the first node.

6. The pixel circuit according to claim 3, wherein The first signal output module includes a second operational amplifier, a first conversion module, and a second on-off control module; The second operational amplifier is configured to convert the fourth optoelectronic signal into a fifth optoelectronic signal and output the fifth optoelectronic signal to the first conversion module; The first conversion module is configured to convert the fifth optoelectronic signal into the third optoelectronic signal; The second on-off control module is respectively electrically connected to the second control voltage terminal, the first conversion module, and the second output line, and is configured to transmit the third optoelectronic signal to the second output line under the control of the second control voltage.

7. The pixel circuit according to claim 6, wherein The first conversion module includes a second transistor, and the second on-off control module includes a third transistor; The control electrode of the second transistor is electrically connected to the output terminal of the second operational amplifier, the first electrode of the second transistor is electrically connected to the power supply voltage terminal, and the second electrode of the second transistor is electrically connected to the first electrode of the third transistor; The control electrode of the third transistor is electrically connected to the second control voltage terminal, and the second electrode of the third transistor is electrically connected to the second output line.

8. The pixel circuit according to claim 1, characterized in that The photosensitive module is respectively electrically connected to the first control terminal and the optoelectronic signal output terminal, and is configured to convert the received optical signal into a first optoelectronic signal and output the first optoelectronic signal through the optoelectronic signal output terminal under the control of the first control signal output by the first control terminal.

9. The pixel circuit according to claim 8, wherein The photosensitive module includes a photodiode and a fourth transistor; The anode of the photodiode is electrically connected to the second voltage terminal, and the cathode of the photodiode is electrically connected to the first electrode of the fourth transistor; The control electrode of the fourth transistor is electrically connected to the first control terminal, and the second electrode of the fourth transistor is electrically connected to the optoelectronic signal output terminal.

10. The pixel circuit according to claim 1, wherein The rolling shutter control module is respectively electrically connected to the second control terminal, the optoelectronic signal output terminal, the first output terminal, and the first output line, and is configured to maintain the potential of the optoelectronic signal output terminal, convert the first optoelectronic signal into a second optoelectronic signal under the control of the second control signal output by the second control terminal, and output the second optoelectronic signal through the first output terminal and the first output line.

11. The pixel circuit according to claim 10, wherein The rolling shutter control module includes a second energy storage module and a second signal output module; The first end of the second energy storage module is electrically connected to the optoelectronic signal output terminal, the second end of the second energy storage module is electrically connected to the second voltage terminal, and the second energy storage module is configured to maintain the potential of the optoelectronic signal output terminal; The second signal output module is electrically connected to the first output terminal, the first output line, and the first end of the second energy storage module, and is configured to convert the first optoelectronic signal into a second optoelectronic signal under the control of the second control signal output by the second control terminal, and output the second optoelectronic signal through the first output terminal and the first output line.

12. The pixel circuit according to claim 11, wherein The second energy storage module includes a second capacitor, and the second signal output module includes a fifth transistor and a sixth transistor; The control electrode of the fifth transistor is electrically connected to the optoelectronic signal output terminal and the first end of the second capacitor respectively. The first electrode of the fifth transistor is electrically connected to the power supply voltage terminal, and the second electrode of the fifth transistor is electrically connected to the first output terminal; the second end of the second capacitor is electrically connected to the second voltage terminal; The control electrode of the sixth transistor is electrically connected to the second control terminal. The first electrode of the sixth transistor is electrically connected to the first output terminal, and the second electrode of the sixth transistor is electrically connected to the first output line.

13. The pixel circuit according to claim 11, wherein The rolling shutter control module further includes a reset module; The reset module is electrically connected to the third control terminal, the first voltage terminal, the first end of the second energy storage module, and the optoelectronic signal output terminal respectively, and is configured to control the first voltage terminal to be communicated with the optoelectronic signal output terminal and the first end of the second energy storage module respectively under the control of a third control signal output by the third control terminal.

14. The pixel circuit according to claim 13, wherein The reset module includes a seventh transistor; The gate of the seventh transistor is electrically connected to the third control terminal. The first electrode of the seventh transistor is electrically connected to the first voltage terminal, and the second electrode of the seventh transistor is electrically connected to the optoelectronic signal output terminal.

15. An image sensor, characterized in that, Comprising the pixel circuit according to any one of claims 1 to 14.

16. An electronic device, characterized in that, Comprising a signal processing module and the image sensor according to claim 15; The signal processing module is connected to the image sensor, and the signal processing module is configured to process the output signal of the image sensor.

17. The electronic device according to claim 16, wherein The signal processing module is connected to the image sensor through a first output line and a second output line; Wherein, the signal processing module obtains a second optoelectronic signal through the first output line; or, the signal processing module obtains a third optoelectronic signal through the second output line.

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