Composite dielectric gate photosensitive detector capable of realizing global shutter in multi-window mode

Abstract

The invention discloses a composite dielectric gate photosensitive detector capable of realizing a global shutter in a multi-window mode, and belongs to the field of digital circuit design. The pixel arrays of the composite dielectric gate photosensitive detector are grouped, N + 1 sets of parallel and independent column reading circuits are configured for N groups of pixel arrays, and a connecting switch is ingeniously arranged, so that the same window is simultaneously read by two sets of parallel column reading circuits in a multi-window windowing mode, the maximum exposure time difference is greatly reduced, and in addition, the maximum exposure time difference is greatly reduced. And subsequently, the exposure difference between different rows is further eliminated through a differential circuit or a programmable gain module, so that picture information under multiple windows can be captured at the same time, instability generated during shooting is weakened, and the imaging effect of a global shutter is achieved.

Description

Technical Field

[0001] The present invention relates to a composite dielectric grating photosensitive detector capable of realizing a global shutter in a multi-window mode, and belongs to the field of digital circuit design. Background Art

[0002] The shutter is a key component in a camera that controls the duration of light exposure to a photosensitive element (such as film or CMOS). The duration of its opening and closing determines the exposure. Depending on their operating principles, shutters can be categorized as rolling shutters or global shutters. Rolling shutters expose pixels on the photosensitive element row or column by row, while global shutters expose all pixels simultaneously.

[0003] Although widely used in modern cameras, the rolling shutter's row-by-row or column-by-column scanning mechanism also brings some significant drawbacks, particularly in dynamic scenes or under specific lighting conditions. These drawbacks manifest themselves in the following aspects: ① Dynamic distortion: When shooting high-speed moving objects or when the camera moves quickly, the sensor's row-by-row exposure causes slight differences in the time it takes to record different parts of the image. This can cause the object's shape to distort. For example, a rapidly rotating propeller may appear to have a curved "S" shape, while a vertically sweeping object (such as a speeding train) may appear tilted. ② Jello effect: If the camera itself is shaken violently (such as when shooting handheld while running), the delay in row-by-row exposure can cause the image to produce a jelly-like elastic jitter. This phenomenon is particularly noticeable in drone aerial photography or sports cameras, affecting visual stability. ③Flicker banding: Under artificial light sources (such as LEDs and fluorescent lights), the light source's flicker frequency may be out of sync with the rolling shutter's scanning frequency, resulting in alternating light and dark stripes in the image. For example, when shooting indoors, certain areas may appear dark due to the light source's "off" cycle. ④Local distortion of fast-moving objects: High-speed moving objects (such as tennis balls and flying birds) may appear partially stretched or compressed in the image, especially at the edges of the frame. For example, the front and rear of a car driving sideways at high speed may appear out of sync due to the difference in scanning time. ⑤Flash synchronization limitations: When using a flash, the rolling shutter must precisely synchronize the flash duration with the sensor scanning process. If the flash duration is shorter than the shutter scanning time, only part of the image may be illuminated (e.g., only the top half is bright). This requires complex high-speed synchronization technology, which increases equipment cost and operational difficulty. ⑥ Inadaptability to high-speed scenes: In professional photography (such as sports and action movies), the distortion problem of rolling shutter may affect the authenticity of the picture and the capture of details; for example, when a golf club is swung, it may appear soft due to deformation, reducing the visual impact.

[0004] Compared with the rolling shutter, the global shutter can capture the light information of the entire picture at the same time, avoiding the deformation problem caused by shooting high-speed moving objects. This feature gives it a significant advantage in specific scenarios. The Chinese invention patent with publication number CN102938409A proposes a composite dielectric grating photosensitive detector. The characteristic of this detector is that a single semiconductor device can realize the complete reset, photosensitivity and readout functions, forming a complete pixel, which can greatly improve the pixel fill factor. This composite dielectric grating photosensitive detector has become a new generation of imaging devices due to its faster operating speed, larger fill factor, more full well charge and ability to be integrated with CMOS technology. However, the shutter method it adopts is a rolling shutter. The configuration of functional modes such as reset, photosensitivity and readout is realized through the gating module in combination with the timing of the rolling shutter.

[0005] Considering the advantages of global shutter over rolling shutter, it is necessary to study the implementation method of global shutter of the above-mentioned composite dielectric grating photosensitive detector. However, due to its streamlined single-tube small pixel characteristics, it is impossible to separate the readout area and the exposure area by setting a transfer node after the exposed transistor like the CIS photosensitive detector. At the same time, it is also unable to meet the high time precision requirements of the mechanical shutter. Therefore, there is still no effective solution for the global shutter of the composite dielectric grating photosensitive detector. Summary of the Invention

[0006] In order to realize the global shutter solution of the composite dielectric grating photosensitive detector and further broaden its application field, the present invention provides a composite dielectric grating photosensitive detector capable of realizing global shutter in multi-window mode, comprising a pixel array of the composite dielectric grating photosensitive detector, a row driving circuit, multiple sets of parallel and independent column readout circuits, and a signal post-processing circuit; wherein the pixel array is divided into N groups with a period of 512 rows, and a set of independent parallel column readout circuits is provided between the groups, and N+1 sets of parallel and independent column readout circuits are provided accordingly; the drain ends of each pixel in the same group of pixel arrays are connected through column-directional bit lines, and a switch is provided between the column-directional bit lines of the first 256 rows of pixels and the last 256 rows of pixels in each group; the column readout circuit between the two groups is connected to the two groups of pixel arrays through a switch respectively; and through the selection of the switch, each window is read out simultaneously using two sets of column readout circuits.

[0007] Optionally, the signal post-processing circuit is a non-correlated double sampling difference circuit or a gain module.

[0008] Optionally, the first 256 rows of pixels in the first pixel array are directly connected to the first set of parallel independent column readout circuits; the last 256 rows of pixels in the Nth pixel array are directly connected to the first set of parallel independent column readout circuits.

[0009] Optionally, the column readout circuit can select to read out the upper 512-row area, the lower 512-row area, or the upper 256-row area plus the lower 256-row area through a switch.

[0010] Optionally, the column readout circuit includes a reset tube, a clamping circuit module, an integrating capacitor, a counter and a comparator, wherein the clamping circuit module is composed of an amplifier and a triode.

[0011] The present invention also provides an exposure imaging method for a composite dielectric grating photosensitive detector capable of realizing a global shutter in a multi-window mode. The method is implemented based on the composite dielectric grating photosensitive detector, and the signal post-processing circuit is a non-correlated double sampling difference circuit. The method includes: Step 1: Allocate readout circuits for multiple windows according to the windowing coordinates of each window, so that each window is read out simultaneously using two sets of column readout circuits; Step 2: According to the row number corresponding to the window coordinates of each window, configure the row state machine register of the corresponding row and set it to the read-out state; Step 3: Based on the row grouping method of the pixel array, the row state machine register in each group is set to the first row of pixels in the readout state to synchronously start the working sequence. The working sequence is controlled by the row driver circuit applying different voltage excitations to the row word line of the row. It is divided into a reset phase, an exposure phase, and a readout phase. In the reset phase, the row driver circuit applies a negative bias voltage less than the substrate voltage, a zero bias voltage is applied in the exposure phase, and a ramp voltage signal is applied in the readout phase to cooperate with the column readout circuit for reading. Step 4: After the readout time of the first row in each row group ends, the second row of pixels in each group whose row state machine register is set to the readout state starts to be read out synchronously, and the working timing sequence of the second row is the same as that of the first row; Step 5: After all rows are reset synchronously, exposure starts synchronously and reads out in sequence. The exposure and readout of the row pixel signals of all row state machine registers in all row groups are completed. The readout result is used as the bright field sampling result DN in the global shutter non-correlated double sampling. Bright ; Step 6: Read out the row pixels whose row state machine registers are set to the readout state according to the method of steps 2 to 4, but set the exposure time of the first row to the shortest exposure time. All rows are exposed synchronously and read out in sequence. The readout result is used as the dark field sampling result DN in the global shutter non-correlated double sampling. Dark ; Step 7: Calculate DN in the uncorrelated double sampling difference module Bright -DN Dark The calculation result is the final global exposure window data output off-chip.

[0012] The present invention also provides another exposure imaging method for a composite dielectric grating photosensitive detector capable of realizing a global shutter in a multi-window mode. The method is implemented based on the composite dielectric grating photosensitive detector, and the signal post-processing circuit is a gain module. The method includes: Step 1: Allocate readout circuits for multiple windows according to the windowing coordinates of each window, so that each window is read out simultaneously using two sets of column readout circuits; Step 2: According to the row number corresponding to the window coordinates of each window, configure the row state machine register of the corresponding row and set it to the read-out state; Step 3: According to the row grouping method of the pixel array, the row state machine register in each group is set to the first row of pixels in the readout state to synchronously start the working sequence; the working sequence is controlled by the row driver circuit applying different voltage excitations to the WL of the row, which is divided into a reset phase, an exposure phase, and a readout phase. In the reset phase, the row driver circuit applies a negative bias voltage less than the substrate voltage, a zero bias voltage is applied in the exposure phase, and a ramp voltage signal is applied in the readout phase to cooperate with the column-directed readout circuit for reading; Step 4: All rows are reset synchronously and exposure starts synchronously. After the readout time of the first row in each row group is over, the row state machine register in each group is set to the readout state and the second row of pixels starts to be read synchronously. The working timing sequence of the second row is the same as that of the first row. All rows are reset synchronously and exposure starts synchronously. Step 5: Multiply the readout result by the coefficient k in the programmable gain module, and the calculated result is the final global exposure window data output off-chip; the k value set for each row is calculated as follows:

[0013] in, is the number of rows, is the coefficient for multiplying each row, is the exposure time, T read The readout time for each line.

[0014] The beneficial effects of the present invention are: By grouping the pixel arrays of composite dielectric grating photosensitive detectors and configuring N+1 sets of parallel independent column readout circuits for N groups of pixel arrays, and by cleverly setting the connection switches, two sets of parallel column readout circuits are used to read out the same window at the same time in the multi-window opening mode, thereby greatly reducing the maximum exposure time difference. Moreover, the exposure differences between different rows are subsequently eliminated through a differential circuit or a programmable gain module, so that it is possible to simultaneously capture image information under multiple windows, reducing the instability generated during shooting. The present invention is applied to scenes with higher temporal resolution, especially when shooting scenes of high-speed motion or fast camera movement, to better ensure shooting quality and solve various problems caused by the rolling shutter exposure mode. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0016] Figure 1 Schematic diagram of a pixel array composed of composite dielectric grating photosensitive detectors in an embodiment of the present invention.

[0017] Figure 2 Schematic diagram of a readout circuit in an embodiment of the present invention.

[0018] Figure 3 Schematic diagram of a row driving circuit according to an embodiment of the present invention.

[0019] Figure 4 This is a flowchart of the overall steps for implementing a global shutter in multi-window opening mode.

[0020] Figure 5 This is a schematic diagram of the row-by-row working sequence operation.

[0021] Figure 6 This is a circuit diagram of an implementation of a non-correlated double sampling differential module.

[0022] Figure 7 This is a circuit diagram of one implementation of a gain block circuit.

[0023] Figure 8 It is a corresponding window opening schematic diagram in the solution of the present invention. DETAILED DESCRIPTION

[0024] To make the objectives, technical solutions and advantages of the present invention more clear, the embodiments of the present invention will be described in further detail below with reference to the accompanying drawings.

[0025] Example 1 This embodiment provides a composite dielectric grating photosensitive detector capable of realizing a global shutter in a multi-window mode, comprising a pixel array of the composite dielectric grating photosensitive detector, a row driving circuit, multiple sets of parallel independent column readout circuits, and a signal post-processing circuit; wherein the pixel array of the composite dielectric grating photosensitive detector is divided into N groups with a period of 512 rows, corresponding to N+1 sets of parallel independent column readout circuits; the drain ends of the pixels in the same group of pixel arrays are connected via a column-oriented bit line (BL), and a switch is provided between the column-oriented bit lines of the first 256 rows of pixels and the last 256 rows of pixels in each group; the group and An independent parallel column readout circuit is provided between the groups; except for the first and last groups, the first 256 rows of pixels and the last 256 rows of pixels in each pixel array are connected to the two independent parallel column readout circuits on both sides through a switch respectively; in the first pixel array, the first 256 rows of pixels are directly connected to the corresponding column readout circuit, and the last 256 rows of pixels are connected to the corresponding column readout circuit through a switch; in the last pixel array, the first 256 rows of pixels are connected to the corresponding column readout circuit through a switch, and the last 256 rows of pixels are directly connected to the corresponding column readout circuit.

[0026] like Figure 1 As shown, the two groups of pixel arrays correspond to three sets of parallel independent column readout circuits Read1, Read2, and Read3. Considering that the column readout circuits corresponding to each column of pixels have the same structure, Figure 1 A set of column readout circuits is shown as a block in FIG.

[0027] In each pixel array, the drain ends of the first 256 rows of pixels are connected via column-oriented bit lines, and the drain ends of the last 256 rows of pixels are connected via column-oriented bit lines, and switches (such as Figure 1 The column-directed bit lines of the first 256 rows of pixels of the first pixel array are directly connected to the column readout circuit Read1, and the column-directed bit lines of the last 256 rows of pixels are connected to the column readout circuit Read2 through the switch S2. At the same time, the column readout circuit Read2 is also connected to the column-directed bit lines of the first 256 rows of pixels of the second pixel array through the switch S3. The column-directed bit lines of the last 256 rows of pixels of the second pixel array are connected to the column readout circuit Read3 through the switch S5. The column readout circuit Read3 is also connected to the column-directed bit lines of the first 256 rows of pixels of the next pixel array through the switch S6, ..., and so on. The column-directed bit lines of the last 256 rows of pixels of the last pixel array are directly connected to the column readout circuit Read N+1 connected.

[0028] In this way, the same readout circuit can perform multiple readout schemes, and can choose to read out the upper 512-row area, the lower 512-row area, or the upper 256-row area plus the lower 256-row area. This allows two sets of readout circuits to read out any windowing method simultaneously, speeding up the process while reducing the maximum exposure time difference between successive rows.

[0029] like Figure 2 As shown, the column readout circuit used in the present invention is an existing circuit, which includes a reset tube Reset, a clamping circuit module, an integral capacitor C int , counter and comparator. Among them, the clamp circuit fixes the voltage of BL, that is, the drain end of the pixel, to keep the read state unaffected by the current. The comparator and counter are used to digitally quantify the read signal. The connection relationship of each part is as follows Figure 2 As shown; Figure 2 The clamp circuit module includes an amplifier and a transistor, V RefClamp is the reference voltage of the amplifier, V OS，Clamp and is the non-ideal factor in the clamping circuit module, where V OS，Clamp Represents the offset deviation in the clamping circuit module, Represents the noise deviation in the clamping circuit module. V RefComp is the reference voltage of the comparator, V OS，Comp and is the non-ideal factor in the comparator circuit, where V OS，Comp represents the offset deviation in the comparator circuit, Represents the noise deviation in the comparator circuit.

[0030] like Figure 3 As shown, the row driving circuit adopted by the present invention is an existing circuit. The row driving circuit corresponding to each row includes a state machine, a level conversion module and a circuit gating module. The level conversion module is composed of three level converters, and the circuit gating module is composed of MOS transistors. The state machine configures the current state output signal to the level conversion module, thereby inputting voltage to the corresponding port in the circuit gating module, thereby achieving the function of realizing three different driving voltages for three different pixel states. Figure 3In the circuit, the EN_READ, EN_EXPO, and EN_RST signals output by the state machine are converted into three signals, VHH, VL, and VLL, through the level conversion module and input into the circuit selection module, which further controls VRAMP (read mode voltage), Vexpo (exposure mode voltage), and Vrst (reset mode voltage) to output one of the three to the WL_SW_OUT port; in the level conversion module, the three level converters CHP_5V, CHP_NEG1P6, and CHP_NEG3 input the same clock signal CLK; LDPMOS1, LDPMOS2, NMOS1, LDNMOS2, OD33NMOS, and LDNMOS3 are MOS tubes in the circuit selection module.

[0031] like Figure 4 As shown, the overall steps of the present invention to realize the global shutter in the multi-window opening mode mainly include setting circuit parameters, allocating readout circuit methods, and cleverly setting connection switches so that in the multi-window opening mode, two sets of parallel column readout circuits can be used to read out the same window at the same time, greatly reducing the maximum exposure time difference. Subsequently, the exposure difference between different rows is further eliminated through a differential circuit or a programmable gain module, so that it can capture the image information in multiple windows at the same time, reducing the instability generated during shooting.

[0032] In this embodiment, the signal post-processing circuit adopts Figure 6 The non-correlated double sampling differential circuit shown in FIG. 1 is implemented. The non-correlated double sampling differential circuit includes three resistors and an operational amplifier, which can achieve the differential function between Data_bright and Data_dark. Other non-correlated double sampling differential circuits that can achieve differential can also be used. This embodiment only uses Figure 6 The circuit structure shown is taken as an example.

[0033] This embodiment takes the simultaneous opening of two windows as an example to introduce the process of realizing a global shutter of a composite dielectric grating photosensitive detector: each window contains 512×512 pixels. The starting coordinates of window ① are the first pixel of the first row of the first 512-row group of the pixel array of the composite dielectric grating photosensitive detector, with coordinates (1,1). The starting coordinates of window ② are (257,513). At this time, it is necessary to read out rows 1 to 768. The window opening diagram is as follows: Figure 8 The specific steps are as follows: Step 1: Assign readout circuits to the two windows: Step 1.1: Turn off the middle dividing line switch S1 in the period group below Read1. At this time, Read1 can read the pixels of the adjacent 256 rows below.

[0034] Step 1.2: Turn on the switch S2 connected upward to Read2 and turn off the switch S3 connected downward to Read2. At this time, Read2 can read the pixels of the upper adjacent 256 rows.

[0035] Step 1.3: Turn on the switch S5 connected upward by Read3 and the middle dividing line switch S4 in the period group below Read2, and turn off the switch S6 connected downward by Read3. At this time, Read3 can read the 256 rows of pixels on the far upper side.

[0036] Step 2: Configure the row state machine register of the corresponding row according to the row number corresponding to the window coordinate and set it to the read-out state; Step 3: Based on the row grouping method of the pixel array, the row state machine register in each group is set to the first row of pixels in the readout state to synchronously start the working sequence. The working sequence is controlled by the row driver circuit applying different voltage excitations to the row word line (WL) of the row. The working sequence is divided into a reset phase, an exposure phase, and a readout phase. The reset phase is applied by the row driver circuit with a negative bias voltage less than the substrate voltage. The exposure phase is applied with a zero bias voltage. The readout phase is applied with a ramp voltage signal, and the column readout circuit is used for reading. Step 4: After the readout time of the first row in each row group ends, the second row of pixels in each group whose row state machine register is set to the readout state starts to be read out synchronously, and the working timing sequence of the second row is the same as that of the first row; Step 5: After all rows are reset synchronously, exposure starts synchronously and reads out in sequence. The exposure and readout of the row pixel signals of all row state machine registers in all row groups are completed. The readout result is used as the bright field sampling result DN in the global shutter non-correlated double sampling. Bright ; Step 6: Read out the row pixels whose row state machine registers are set to the readout state according to the method of steps 2 to 4, but set the exposure time of the first row to the shortest exposure time. All rows are exposed synchronously and read out in sequence. The readout result is used as the dark field sampling result DN in the global shutter non-correlated double sampling. Dark ; Step 7: Calculate DN in the uncorrelated double sampling difference module Bright -DN Dark The calculation result is the final global exposure window data output off-chip.

[0037] Combined with the two windows of this embodiment, assuming that the readout time of a row of pixels is T read ,Depend on Figure 5 It can be seen that the exposure time difference between the first row and the nth row read by the same readout circuit is (n-1)×T read Specifically for the two windows in this embodiment, the maximum exposure time difference will reach 767×Tread , and after adopting the above-mentioned pixel array and exposure timing in this embodiment, it can be reduced to 255×T read , greatly reducing the maximum exposure time difference.

[0038] In this embodiment, a non-correlated double sampling differential circuit is used as a signal post-processing module. The differential circuit can subtract the signal that increases due to the extra exposure time of the rows read out later than the rows read out earlier due to simultaneous exposure, thereby further reducing the adverse effects of the rolling shutter exposure mode and achieving the effect of global exposure.

[0039] Example 2 This embodiment provides a composite dielectric grating photosensitive detector capable of realizing a global shutter in a multi-window mode, comprising a pixel array of the composite dielectric grating photosensitive detector, a row driving circuit, multiple sets of parallel independent column readout circuits, and a signal post-processing circuit. The description of the components is the same as that in the first embodiment, except that the signal post-processing circuit in this embodiment adopts Figure 7 The programmable gain block implementation shown.

[0040] like Figure 7 As shown in FIG, the programmable gain module includes three resistors, an adjustable resistor Rt and an operational amplifier. The gain of the input signal can be adjusted by adjusting the adjustable resistor Rt. Figure 7 Only one implementation of the programmable gain module is provided. Other circuits capable of adjusting the gain of the input signal may also be used, and the present invention does not limit this.

[0041] This embodiment also takes the simultaneous opening of two windows as an example to introduce the process of realizing the global shutter of the composite dielectric grating photosensitive detector: each window contains 512×512 pixels, the starting coordinates of window ① are the first pixel point of the first row of the first 512-row group of the pixel array of the composite dielectric grating photosensitive detector, and the coordinates are (1,1), and the starting coordinates of window ② are (257,513). At this time, it is necessary to read out the 1st to 768th rows. The window opening diagram is as follows Figure 8 The specific steps are as follows: Step 1: Assign readout circuits to the two windows: Step 1.1: Turn off the middle dividing line switch S1 in the period group below Read1. At this time, Read1 can read the pixels of the adjacent 256 rows below.

[0042] Step 1.2: Turn on the switch S2 connected upward to Read2 and turn off the switch S3 connected downward to Read2. At this time, Read2 can read the pixels of the upper adjacent 256 rows.

[0043] Step 1.3: Turn on the switch S5 connected upward by Read3 and the middle dividing line switch S4 in the period group below Read2, and turn off the switch S6 connected downward by Read3. At this time, Read3 can read the pixels of the upper far side 256 rows.

[0044] Step 2: Configure the row state machine register of the corresponding row according to the row number corresponding to the window coordinate and set it to the read-out state; Step 3: Based on the row grouping of the pixel array, the row state machine registers within each group are set to the first row of pixels in the readout state, and the operation sequence begins synchronously. The operation sequence is controlled by the row driver circuit applying different voltage excitations to the WL of the row. It is divided into a reset phase, an exposure phase, and a readout phase. The reset phase is applied by the row driver circuit with a negative bias voltage less than the substrate voltage. The exposure phase is applied with a zero bias voltage. The readout phase is applied with a ramp voltage signal, which is then read out in conjunction with the column-directed readout circuit. Step 4: All rows are reset synchronously and exposure starts synchronously. After the readout time of the first row in each row group is over, the row state machine register in each group is set to the readout state and the second row of pixels starts to be read synchronously. The working timing sequence of the second row is the same as that of the first row. All rows are reset synchronously and exposure starts synchronously. Step 5: Multiply the readout result by the coefficient k in the programmable gain module, and the calculated result is the final global exposure window data output off-chip. The k value set for each row is calculated as follows:

[0045] in, is the number of rows, is the coefficient for multiplying each row, is the exposure time, T read The readout time for each line.

[0046] Similarly, after adopting the above-mentioned pixel array and exposure timing in this embodiment, the maximum exposure time difference is 767×T read Reduced to 255×T read ,Furthermore, the gain module processing method is used to ,scale the amount of redundant exposure signals in each row to be consistent.

[0047] Both embodiments of the present invention are introduced using two windows as an example. In actual application scenarios, in the multiple window opening mode, by opening and closing each switch, each window can use two readout circuits for readout operations, which greatly reduces the maximum exposure time difference. Combined with the differential circuit or gain module, the adverse effects of the rolling shutter exposure mode can be further reduced, achieving the effect of global exposure.

[0048] Some steps in the embodiments of the present invention may be implemented using software, and the corresponding software program may be stored in a readable storage medium, such as a CD or a hard disk.

[0049] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A composite dielectric grating photodetector capable of realizing a global shutter in a multi-window mode, characterized in that: The composite dielectric grating photosensitive detector includes a pixel array of the composite dielectric grating photosensitive detector, a row driving circuit, multiple sets of parallel and independent column readout circuits, and a signal post-processing circuit; wherein the pixel array is divided into N groups with a period of 512 rows, and a set of independent parallel column readout circuits is provided between the groups, and N+1 sets of parallel and independent column readout circuits are provided accordingly; the drain ends of each pixel in the same group of pixel arrays are connected through a column-oriented bit line, and a switch is provided between the column-oriented bit lines of the first 256 rows of pixels and the last 256 rows of pixels in each group; the column readout circuit between the two groups is connected to the two groups of pixel arrays through a switch respectively; and through the selection of the switch, each window can be read out simultaneously using two sets of column readout circuits.

2. The composite dielectric grating photosensitive detector according to claim 1, characterized in that: The signal post-processing circuit is a non-correlated double sampling difference circuit or a gain module.

3. The composite dielectric grating photosensitive detector according to claim 2, characterized in that: The first 256 rows of pixels in the first pixel array are directly connected to the first set of parallel independent column readout circuits; the last 256 rows of pixels in the Nth pixel array are directly connected to the first set of parallel independent column readout circuits.

4. The composite dielectric grating photosensitive detector according to claim 3, characterized in that: The column readout circuit can select to read out the upper 512-row area, the lower 512-row area, or the upper 256-row area plus the lower 256-row area through a switch.

5. The composite dielectric grating photosensitive detector according to claim 4, characterized in that: The column readout circuit includes a reset tube, a clamping circuit module, an integrating capacitor, a counter and a comparator, wherein the clamping circuit module is composed of an amplifier and a triode.

6. An exposure imaging method for a composite dielectric grating photosensitive detector capable of realizing a global shutter in a multi-window mode, characterized in that: The method is implemented based on the composite dielectric grating photosensitive detector according to claim 1, and the signal post-processing circuit is a non-correlated double sampling difference circuit. The method includes: Step 1: Allocate readout circuits for multiple windows according to the windowing coordinates of each window, so that each window is read out simultaneously using two sets of column readout circuits; Step 2: According to the row number corresponding to the window coordinates of each window, configure the row state machine register of the corresponding row and set it to the read-out state; Step 3: Based on the row grouping method of the pixel array, the row state machine register in each group is set to the first row of pixels in the readout state to synchronously start the working sequence. The working sequence is controlled by the row driver circuit applying different voltage excitations to the row word line of the row. It is divided into a reset phase, an exposure phase, and a readout phase. In the reset phase, the row driver circuit applies a negative bias voltage less than the substrate voltage, a zero bias voltage is applied in the exposure phase, and a ramp voltage signal is applied in the readout phase to cooperate with the column readout circuit for reading. Step 4: After the readout time of the first row in each row group ends, the second row of pixels in each group whose row state machine register is set to the readout state starts to be read out synchronously, and the working timing sequence of the second row is the same as that of the first row; Step 5: After all rows are reset synchronously, exposure starts synchronously and reads out in sequence. The exposure and readout of the row pixel signals of all row state machine registers in all row groups are completed. The readout result is used as the bright field sampling result DN in the global shutter non-correlated double sampling. Bright ; Step 6: Read out the row pixels whose row state machine registers are set to the readout state according to the method of steps 2 to 4, but set the exposure time of the first row to the shortest exposure time. All rows are exposed synchronously and read out in sequence. The readout result is used as the dark field sampling result DN in the global shutter non-correlated double sampling. Dark ; Step 7: Calculate DN in the uncorrelated double sampling difference module Bright -DN Dark The calculation result is the final global exposure window data output off-chip.

7. An exposure imaging method for a composite dielectric grating photosensitive detector capable of realizing a global shutter in a multi-window mode, characterized in that: The method is implemented based on the composite dielectric grating photosensitive detector according to claim 1, and the signal post-processing circuit is a gain module. The method includes: Step 1: Allocate readout circuits for multiple windows according to the windowing coordinates of each window, so that each window is read out simultaneously using two sets of column readout circuits; Step 2: According to the row number corresponding to the window coordinates of each window, configure the row state machine register of the corresponding row and set it to the read-out state; Step 3: According to the row grouping method of the pixel array, the row state machine register in each group is set to the first row of pixels in the readout state to synchronously start the working sequence; the working sequence is controlled by the row driver circuit applying different voltage excitations to the WL of the row, which is divided into a reset phase, an exposure phase, and a readout phase. In the reset phase, the row driver circuit applies a negative bias voltage less than the substrate voltage, a zero bias voltage is applied in the exposure phase, and a ramp voltage signal is applied in the readout phase to cooperate with the column-directed readout circuit for reading; Step 4: All rows are reset synchronously and exposure starts synchronously. After the readout time of the first row in each row group is over, the row state machine register in each group is set to the readout state and the second row of pixels starts to be read synchronously. The working timing sequence of the second row is the same as that of the first row. All rows are reset synchronously and exposure starts synchronously. Step 5: Multiply the readout result by the coefficient k in the programmable gain module, and the calculated result is the final global exposure window data output off-chip; the k value set for each row is calculated as follows: in, is the number of rows, is the coefficient for multiplying each row, is the exposure time, T read The readout time for each line.

Images