Image sensors, sensor architectures, camera modules and electronic devices

Abstract

This application discloses an image sensor, sensor architecture, camera module, and electronic device, belonging to the field of image processing. It includes: a pixel array, a conversion gain selection module, and a conversion gain signal buffer and driving module; the pixel array includes N rows of pixel units and M columns of pixel units, with N pixel units in the same column connected to the conversion gain signal buffer and driving module via a first connection line, and N pixel units in the same column connected to the conversion gain selection module via a second connection line, where M and N are both positive integers; wherein, the conversion gain selection module is used to generate a conversion gain selection table based on the pixel signals output by the pixel array, the conversion gain selection table including the conversion gain mode selection signal corresponding to each pixel unit; the conversion gain signal buffer and driving module is used to read the gain mode selection signal corresponding to each pixel unit row by row from the conversion gain selection table, and send the gain mode selection signal to the corresponding pixel unit.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of image processing, and particularly relates to an image sensor, a sensor architecture, a camera module and an electronic device. BACKGROUND

[0002] In a Complementry Metal-Oxide Semiconductor (CMOS) image sensor, the dynamic range adjustment of an image is generally achieved by changing the pixel exposure time of all pixels and adjusting the pixel signal gain as a whole.

[0003] In the related art, in Triple Conversion Gain (TCG-HDR) technology, all pixels are exposed together, and the output signals are amplified with different gains. All pixel units need to be exposed in high-gain mode, medium-gain mode and low-gain mode respectively, and then three frames of images are read at one time, and the three frames of images are synthesized. However, the HDR image obtained by synthesis often has color layering and Signal to Noise Ratio (SNR) difference due to processing defects. For example, in some scene output images, some pixels are locally overexposed or some pixels are underexposed. SUMMARY

[0004] The purpose of the embodiments of the present application is to provide an image sensor, a sensor architecture, a camera module and an electronic device, which can solve the problem of poor output image imaging effect caused by the fact that the conversion gain high dynamic range technology cannot be modulated pixel by pixel.

[0005] In a first aspect, the embodiments of the present application provide an image sensor method, comprising a pixel array, a conversion gain selection module and a conversion gain signal buffer and driving module;

[0006] The pixel array comprises N rows of pixel units and M columns of pixel units. N pixel units in the same column are connected to the conversion gain signal buffer and driving module through a first connection line, and N pixel units in the same column are connected to the conversion gain selection module through a second connection line. M and N are positive integers.

[0007] The conversion gain selection module is configured to generate a conversion gain selection table according to the pixel signal output by the pixel array, and the conversion gain selection table comprises a conversion gain mode selection signal corresponding to each pixel unit.

[0008] The conversion gain signal buffer and driving module is configured to read the gain mode selection signal corresponding to each pixel unit from the conversion gain selection table row by row, and transmit the gain mode selection signal to the corresponding pixel unit.

[0009] In a second aspect, an embodiment of the present application provides a sensor architecture, comprising: a pixel layer and a circuit layer.

[0010] The pixel layer comprises: a first bonding region and a pixel array, wherein the pixel array is communicatively connected with the first bonding region.

[0011] The circuit layer comprises: a second bonding region, a conversion gain selection module and a conversion gain signal buffer and driving module, wherein the second bonding region is communicatively connected with the conversion gain selection module and the conversion gain signal buffer and driving module respectively, and the first bonding region is bonded with the second bonding region.

[0012] In a third aspect, an embodiment of the present application provides a camera module, comprising the image processor of the first aspect.

[0013] In a fourth aspect, an embodiment of the present application provides an electronic device, comprising the camera module of the third aspect.

[0014] In the embodiment of the present application, the conversion gain mode selection module can automatically determine the conversion gain mode selection signal corresponding to each pixel unit according to the pixel signal output by each pixel unit, and the conversion gain signal buffer and driving module can read the gain mode selection signal corresponding to each pixel unit from the conversion gain selection table row by row, and then transmit the gain mode selection signal to each pixel unit, so that each pixel can select to run in a low gain mode, a medium gain mode or a high gain mode according to the adaptive logic in each frame of time, thereby realizing pixel-level gain adjustment and avoiding the problems of partial pixel local overexposure or partial pixel underexposure caused by three-time exposure. The scheme of the present application does not need to change the traditional pixel structure, and does not change the traditional image processor reading and signal processing mode, and can accurately control the gain mode selection of each pixel by using column parallel control method. BRIEF DESCRIPTION OF DRAWINGS

[0015] Figure 1 FIG. 1 is a structural schematic diagram of a pixel unit in an embodiment of the present application;

[0016] Figure 2 FIG. 2 is a structural schematic diagram of an image sensor provided by an embodiment of the present application;

[0017] Figure 3 FIG. 3 is a structural schematic diagram of a conversion gain selection module provided by an embodiment of the present application;

[0018] Figure 4 Figure 2 is a schematic diagram of an image sensor structure according to an embodiment of the present application;

[0019] Figure 5 Figure 3 is a schematic diagram of a sensor architecture according to an embodiment of the present application. DETAILED DESCRIPTION

[0020] The technical solutions in the embodiments of the present application will be clearly described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art belong to the scope of protection of the present application.

[0021] The terms "first", "second", and the like in the specification and claims of the present application are used to distinguish similar objects, and are not used to describe a specific order or sequence. It should be understood that the data used in this way can be exchanged under appropriate circumstances, so that the embodiments of the present application can be implemented in an order other than those illustrated or described herein, and the objects distinguished by "first", "second", etc. are generally a category and do not limit the number of objects, for example, the first object can be one or more. In addition, "and / or" in the specification and claims indicates at least one of the connected objects, and the character " / ", generally indicates that the front and rear associated objects are in a "or" relationship.

[0022] The image sensor, sensor architecture, camera module and electronic device provided by the embodiments of the present application will be described in detail below in combination with the drawings and specific embodiments and application scenarios.

[0023] Figure 1This is a schematic diagram of the pixel unit structure in an embodiment of this application. The photodiode (PD) in the optical module of the pixel unit is responsible for photosensitivity and photoelectric conversion in each frame. The generated charge e- is buffered in the floating diffusion (FD) capacitor after being switched by the TX transistor. During the readout phase, the charge e- in the FD is amplified by the source follower (SF) transistor and converted into a corresponding voltage, which is then output as the pixel signal PIX_OUT to the outside of the pixel after being switched by the SEL transistor. The RST transistor is responsible for resetting the FD to voltage VDD. The TCG function is used to change the size of the FD. In High Conversion Gain (HCG) mode, the FD needs to be as small as possible. In Low Conversion Gain (LCG) mode, the FD needs to be as large as possible. Therefore, a Middle Conversion Gain (MCG), an LCG transistor switch, and capacitors C1 and C2 are added to the pixel circuit. The MCG transistor switch is responsible for the mode conversion between HCG and MCG, while capacitor C1 is responsible for expanding the capacitance of the FD capacitor. The LCG transistor switch is responsible for LCG mode switching, while capacitor C2 further expands the capacitance of the FD capacitor. When a pixel needs to operate in HCG mode, the MCG and LCG transistor switches are open, and FD receives the charge e- transferred from PD. When a pixel needs to operate in MCG mode, the MCG transistor closes, connecting FD with C1 to expand the capacitance (the RST transistor switch must remain open to prevent reset). Therefore, the charge e- transferred from PD is FD + C1. When a pixel needs to operate in LCG mode, both the MCG and LCG transistors close simultaneously, connecting FD with C1 and C2 to expand the capacitance (the RST transistor switch must remain open to prevent reset). Therefore, the charge e- transferred from PD is FD + C1 + C2. In summary, the essential method for implementing the TCG function is to change the size of the FD capacitor as needed.

[0024] Figure 2 This is one of the schematic diagrams of the image sensor structure provided in the embodiments of this application, such as... Figure 2 As shown, it includes: a pixel array 11, a conversion gain selection module 12, and a conversion gain signal buffer and driving module 13;

[0025] The pixel array 11 includes N rows of pixel units 110 and M columns of pixel units 110. N pixel units 110 in the same column are connected to the conversion gain signal buffer and driving module 13 through a first connection line, and N pixel units 110 in the same column are connected to the conversion gain selection module 12 through a second connection line. M and N are both positive integers.

[0026] The conversion gain selection module 12 is used to generate a conversion gain selection table based on the pixel signal output by the pixel array 11. The conversion gain selection table includes a conversion gain mode selection signal corresponding to each pixel unit.

[0027] The conversion gain signal buffer and drive module 13 is used to read the gain mode selection signal corresponding to each pixel unit from the conversion gain selection table row by row, and send the gain mode selection signal to the corresponding pixel unit.

[0028] Specifically, the pixel array described in the embodiments of this application includes multiple pixel units, which may include N pixel rows in the same row and M pixel columns in the same column, corresponding to NxM pixel units in each pixel array.

[0029] In this embodiment of the application, in order to further save wiring space, N pixel units in the same pixel column are connected to the conversion gain signal buffer and driving module through the same first connection line, and N pixel units in the same pixel column are also connected to the conversion gain selection module through the same second connection line.

[0030] In this embodiment, each pixel unit's working time in each frame is divided into three periods: a reset period, an exposure period, and a readout period. The row driver of the pixel array controls the reset and readout signals for each row of pixels, and there is a certain time difference between the reset and readout processes of different rows. This allows for a time difference between the pixel signal output of each row and that of other rows, enabling the column-parallel ADC to process only one row of pixel signals at a time. After each row of pixels completes its readout, it directly enters the next frame without needing to consider the state of other rows. When all rows of pixels have been read, the pixel signal corresponding to one frame is output to the conversion gain selection module.

[0031] In this embodiment, the pixel signal output by the pixel array can be the signal output by the pixel unit in the current frame after reset and exposure processing. The pixel signal output by each pixel unit can be a different pixel signal. In this embodiment, the conversion gain selection module can determine the gain mode selection signal corresponding to each pixel unit in the next frame based on the pixel signal of the current frame.

[0032] In an optional embodiment, the conversion gain selection module is used to determine the corresponding gain mode selection signal based on the pixel signal output by each pixel unit, and then generate a conversion gain selection table based on the gain mode selection signal corresponding to each pixel unit.

[0033] In this embodiment, the conversion gain selection table records the gain mode selection signal corresponding to each pixel unit. Optionally, the gain mode selection signals in the conversion gain selection table can be sorted according to the arrangement of the pixel array.

[0034] In an optional embodiment, the conversion gain selection module may include a row buffer submodule and a row driving submodule. The row buffer submodule in the conversion gain selection module can read the gain mode selection signal corresponding to each pixel unit row by row according to the pixel row arrangement of the pixel array. The row buffer submodule of the conversion gain signal buffer and driving module can buffer only the gain mode selection signal of one row of pixel units at a time.

[0035] During the exposure process of the rolling shutter, when a pixel unit in a certain row of the pixel array enters the readout period and needs to provide a gain mode selection signal for readout mode selection, the row driver submodule drives the row buffer submodule to send the buffered gain mode selection signal to the pixel unit of the corresponding row.

[0036] More specifically, the gain mode selection signal corresponding to each pixel unit can be a digital signal or an analog signal. This gain mode selection signal will control the pixel unit to output the pixel signal according to the gain mode indicated by the gain mode selection signal within the next image frame.

[0037] In this embodiment, the conversion gain mode selection module can effectively determine the corresponding conversion gain mode selection signal for each pixel unit based on the pixel signal output by each pixel unit. Furthermore, the conversion gain signal buffer and driving module reads the gain mode selection signal corresponding to each pixel unit row by row from the conversion gain selection table and transmits the gain mode selection signal to each pixel unit. Each pixel selects to operate in low gain mode, medium gain mode, or high gain mode according to adaptive logic in each frame, thereby achieving pixel-level gain adjustment. This avoids the problem of local overexposure or underexposure of some pixels caused by three exposures. The solution of this application does not need to change the traditional pixel structure or the traditional image processor reading and signal processing method. The column parallel control method can achieve accurate control of the gain mode selection of each pixel.

[0038] Optionally, the conversion gain selection module includes: a first comparator, a second comparator, and a conversion gain indicator, wherein the conversion gain indicator is communicatively connected to the first comparator and the second comparator, respectively.

[0039] The first comparator is used to compare the pixel signal corresponding to each pixel unit with a first preset threshold signal to obtain the first comparator output signal corresponding to each pixel unit;

[0040] The second comparator is used to compare the pixel signal corresponding to each pixel unit with the second preset threshold signal to obtain the second comparator output signal corresponding to each pixel unit;

[0041] The conversion gain indicator is used to buffer the first comparator output signal and the second comparator output signal, and to generate the conversion gain selection table based on the first comparator output signal and the second comparator output signal.

[0042] Figure 3 This is a schematic diagram of the conversion gain selection module structure provided in an embodiment of this application, as shown below. Figure 3 As shown, it includes: a first comparator 21, a second comparator 22 and a conversion gain indicator 23, wherein the conversion gain indicator 23 is communicatively connected to the first comparator 21 and the second comparator 22 respectively.

[0043] In an optional embodiment, the first comparator and the second comparator can be digital comparators, and the first preset threshold signal can be a threshold preset by the user, specifically a fixed preset threshold signal. Optionally, different first preset threshold signals and second preset threshold signals can be set when comparing pixel signals of different pixel units.

[0044] In an optional embodiment, the first preset threshold signal and the second preset threshold signal can be the same threshold signal or different threshold signals.

[0045] In an optional embodiment, the first preset threshold signal may be used to determine whether the MCG mode is selected or not, and the second preset threshold signal may be used to determine whether the LCG mode is selected or not. When the pixel signal is a binary digital signal, the first preset threshold signal and the second preset threshold signal may also be binary 10-bit binary numbers.

[0046] In an optional embodiment, after the image data output by each pixel unit is converted into a data signal, it can be compared with a first preset threshold signal pre-set by the user into a first comparator (COMP). For the signal output by each pixel, a comparison result can be obtained, thereby obtaining the corresponding first comparator output signal for each pixel unit.

[0047] Correspondingly, it can also be compared with a second preset threshold signal pre-set by the user into the second comparator. For the signal output by each pixel, a comparison result can be obtained, and thus the corresponding second comparator output signal of each pixel unit can be obtained.

[0048] In an optional embodiment, since there may be a certain time difference between the comparison results of the first comparator and the second comparator, a conversion gain indicator is needed to buffer the output signals of the first comparator and the second comparator.

[0049] After the two comparisons of each pixel are completed, the comparison results are transferred to the conversion gain selection table for storage. After all pixel units have been compared, the conversion gain selection table is obtained.

[0050] In this embodiment of the application, the first comparator and the second comparator can effectively analyze the pixel signals output by different pixel units, thereby effectively obtaining the gain mode suitable for each pixel unit, effectively ensuring the quality of the final generated image, and the conversion gain indicator can effectively buffer the output signals of the first comparator and the second comparator, and generate a conversion gain selection table.

[0051] Optionally, the first comparator is specifically used for:

[0052] When the pixel signal is greater than the first preset threshold signal, the first comparator output signal corresponding to the pixel unit is a first high-level output signal.

[0053] When the pixel signal is less than or equal to the first preset threshold signal, the first comparator output signal corresponding to the pixel unit is a first low-level output signal.

[0054] The second comparator is specifically used for:

[0055] When the pixel signal is greater than the second preset threshold signal, the output signal of the second comparator corresponding to the pixel unit is a second high-level output signal;

[0056] When the pixel signal is less than or equal to the second preset threshold signal, the output signal of the second comparator corresponding to the pixel unit is a second low-level output signal.

[0057] Specifically, in this embodiment, a high-level output signal can be recorded as "1" in the conversion gain selection table, and a low-level output signal can be recorded as "0". For each pixel's output signal, a comparison result can be obtained, and the result is buffered in the conversion gain selection table according to the pixel unit's position in the pixel array. It is agreed that a binary digital signal "1" represents enabling the pixel to enter high-gain mode for reading, and a binary digital signal "0" represents enabling the pixel to enter low-gain mode for reading. In specific implementations, it can also be agreed that the reverse is used, but a 1-bit binary signal must be used.

[0058] In an alternative embodiment, if the user does not require the TCG-HDR function, the conversion gain signal buffer and driver module can be forcibly disabled and their operation can be stopped.

[0059] The conversion gain indicator is specifically used for:

[0060] When the first comparator output signal is a first high-level output signal and the second comparator output signal is a second high-level output signal, the gain mode selection signal of the pixel unit is obtained as a low-gain mode selection signal.

[0061] When the first comparator output signal is a first low-level output signal and the second comparator output signal is a second high-level output signal, the gain mode selection signal of the pixel unit is obtained as a medium-gain mode selection signal.

[0062] When the first comparator output signal is a first high-level output signal and the second comparator output signal is a second low-level output signal, the gain mode selection signal of the pixel unit is obtained as a low-gain mode selection signal.

[0063] When the first comparator output signal is a first low-level output signal and the second comparator output signal is a second low-level output signal, the gain mode selection signal of the pixel unit is obtained as a high-gain mode selection signal.

[0064] In an optional embodiment, if the first comparator output signal is a first high-level output signal, it indicates that the first comparison selected the low-gain mode; if the second comparator output signal is a second high-level output signal, it indicates that the second comparison selected the medium-gain mode. In this case, the gain mode selection signal of the final pixel unit is the low-gain mode selection signal.

[0065] In an optional embodiment, if the first comparator output signal is a first low-level output signal, it indicates that the low-gain mode was not selected in the first comparison. If the second comparator output signal is a second high-level output signal, it indicates that the medium-gain mode was selected in the second comparison. Finally, the gain mode selection signal of the pixel unit is a medium-gain mode selection signal.

[0066] In an optional embodiment, if the first comparator output signal is a first high-level output signal, it indicates that the first comparison selected the low-gain mode, and if the second comparator output signal is a second low-level output signal, it indicates that the second comparison did not select the medium-gain mode, and the gain mode selection signal of the pixel unit is obtained as the low-gain mode selection signal.

[0067] In an optional embodiment, if the first comparator output signal is a first low-level output signal, it indicates that the low-gain mode was not selected in the first comparison. If the second comparator output signal is a second low-level output signal, it indicates that the medium-gain mode was not selected in the second comparison either, and the gain mode selection signal of the pixel unit is obtained as a high-gain mode selection signal.

[0068] In an optional embodiment, when any column of the pixel array needs to determine the HCG, MCG, or LCG readout mode during the readout period, the conversion gain signal buffer and driver module pushes a buffered 2-bit conversion gain selection signal as the LCG and MCG signals. After being driven by the corresponding column driver, this signal is transmitted to the pixel array to provide the pixels in that column with the option to read in LCG, MCG, or HCG mode. Here, it is agreed that the digital signals "LCG=1 and MCG=1" represent that the pixel enters LCG mode for readout, "LCG=0 and MCG=1" represent that the pixel enters MCG mode for readout, and "LCG=0 and MCG=0" represent that the pixel enters HCG mode for readout. If the user does not require the adaptive TCG-HDR function, the column buffer in the column-parallel TCG mode signal buffer and driver module is forced to store / buffer binary digital signals "0" or "1".

[0069] In this embodiment, the comparator can effectively analyze the pixel signals output by different pixel units, thereby effectively obtaining the gain mode suitable for each pixel unit and ensuring the quality of the final generated image.

[0070] Optionally, the conversion gain selection module includes: an independent image signal processor;

[0071] The independent image signal processor is used to perform pixel-by-pixel analysis on the pixel signal output by the pixel array according to the stored program algorithm to obtain the gain mode selection signal corresponding to each pixel unit;

[0072] The conversion gain selection table is generated based on the gain mode selection signal corresponding to each pixel unit.

[0073] Specifically, in the embodiments of this application, the program algorithm may be an algorithm that analyzes the image data of each pixel unit and determines the gain mode of each pixel. Specifically, the algorithm may be an algorithm that, after inputting the pixel signal of each pixel unit, can output the corresponding gain mode selection signal.

[0074] In an optional embodiment, it may be an algorithm that simulates a comparator through a program algorithm, thereby obtaining a gain mode selection signal corresponding to each pixel unit by analyzing the pixel signal output by the pixel array pixel by pixel. This algorithm may also be other algorithms that can achieve the corresponding function.

[0075] In an optional embodiment, after obtaining the gain mode selection signal corresponding to each pixel unit, the gain mode selection signal can be further stored in the corresponding position according to the arrangement of the pixel array and the row and column distribution of the pixel units to obtain the final conversion gain selection table.

[0076] In an optional embodiment, the stored program algorithm may be stored inside the image sensor or integrated outside the image sensor.

[0077] When the algorithm is integrated outside the image sensor, it can be stored in a separate image signal processor outside the image sensor.

[0078] In the embodiments of this application, the program algorithm integrated by the software program module can perform pixel unit analysis one by one in software, which can effectively reduce the number of transistors in the image sensor and save costs while ensuring image quality.

[0079] Optionally, the sensor further includes an interface module, which is communicatively connected to the conversion gain signal buffer and driving module and the pixel array, respectively.

[0080] The interface module is used to transmit the pixel signals output by the pixel array to the independent image signal processor, and to receive the gain mode selection signals corresponding to each pixel unit transmitted by the independent image signal processor.

[0081] In an alternative embodiment, the interface module may specifically be an interface for data transmission with a separate image signal processor.

[0082] Figure 4 This is a second schematic diagram of the image sensor structure provided in the embodiments of this application, as shown below. Figure 4As shown, it includes: a pixel array 11, an independent image signal processor 31, a conversion gain signal buffer and drive module 13, and an interface module 32.

[0083] In this embodiment, the interface module is communicatively connected to the conversion gain signal buffer and driving module and the pixel array, respectively. The interface module can transmit the pixel signals of each pixel unit in the pixel array to the independent image signal processor, so that the independent image signal processor can analyze the gain mode corresponding to each pixel unit according to the pixel signal and obtain the conversion gain selection table.

[0084] The interface module can also receive gain mode selection signals for each column of pixels from an independent image signal processor.

[0085] In this embodiment, the interface module can effectively send image data to an independent image signal processor for gain mode analysis and receive the gain mode selection signal corresponding to each pixel unit sent back by the independent image signal processor, which can effectively ensure image quality while effectively reducing the number of transistors.

[0086] Optionally, the pixel array further includes a signal reading module, wherein N pixel units in the same column are connected to the signal reading module via the second connection line;

[0087] The signal reading module is used to perform analog-to-digital conversion on the pixel signals output by each pixel unit and then transmit them to the conversion gain selection module.

[0088] In an optional embodiment, during each frame time, after each pixel unit has completed its reset and exposure, a reading phase is entered, at which time the signal reading module reads the image data generated by each pixel unit.

[0089] After the signal reading module reads the image data, the image data is often an analog signal, which is not convenient for direct processing. Therefore, it can be converted from analog to digital to a digital signal before being transmitted to the high dynamic range logic module.

[0090] In an optional embodiment, the signal reading module may include an analog-to-digital conversion module and an image signal processor. The analog-to-digital conversion module is connected to the image signal processor, and the N pixel units in the same column are connected to the conversion gain selection module via a second connection line through the signal reading module.

[0091] In this embodiment of the application, by performing analog-to-digital conversion on the pixel signals output by each pixel unit, it is possible to effectively ensure that the pixel signals can be effectively analyzed subsequently.

[0092] Figure 5This is a schematic diagram of the sensor architecture provided in the embodiments of this application, such as... Figure 5 As shown, it includes: pixel layer 51 and circuit layer 52;

[0093] The pixel layer 51 includes: a first bonding region 510 and a pixel array 11, wherein the pixel array 11 is communicatively connected to the first bonding region 510;

[0094] The circuit layer 52 includes: a second bonding region 520, a conversion gain selection module 12, and a conversion gain signal buffer and driving module 13. The second bonding region 520 is communicatively connected to the conversion gain selection module 12 and the conversion gain signal buffer and driving module 13, respectively. The first bonding region 510 is bonded to the second bonding region 520.

[0095] Specifically, in the embodiments of this application, the pixel layer and the circuit layer can be composed of silicon wafer layers. The pixel layer is specifically a pixel silicon wafer layer, and all pixel units are disposed on the pixel layer. The pixel layer can be manufactured using front-side illumination (FSI) or back-side illumination (BSI) processes.

[0096] In this embodiment, the pixel layer is arranged with an effective pixel array, and a first bonding area can be set around the pixel array for signal routing, thereby realizing the connection between the pixel layer and the circuit layer.

[0097] The pixel layer silicon wafer only houses the pixel array, and all input and output signals for the pixels are provided by the underlying circuit layer silicon wafer. The signal connection between the two layers uses methods such as TSV (Trans-Silicon Via) or Cu-Cu Hybrid Bonding.

[0098] The conversion gain selection module, conversion gain signal buffer and driver module, and interface module can all be set in the circuit layer.

[0099] In an alternative embodiment, when the conversion gain selection module is integrated into the software of the pixel sensor, a high dynamic range logic module is not provided in the corresponding circuit layer.

[0100] External HDR logic software can connect to the image sensor's I / O pins and the parallel TCG mode signal buffer and driver module under the coordination of the port module.

[0101] In this embodiment, the conversion gain mode selection module can effectively determine the corresponding conversion gain mode selection signal for each pixel unit based on the pixel signal output by each pixel unit. Furthermore, the conversion gain signal buffer and driving module reads the gain mode selection signal corresponding to each pixel unit row by row from the conversion gain selection table and transmits the gain mode selection signal to each pixel unit. Each pixel selects to operate in low gain mode, medium gain mode, or high gain mode according to adaptive logic in each frame, thereby achieving pixel-level gain adjustment. This avoids the problem of local overexposure or underexposure of some pixels caused by three exposures. The solution of this application does not need to change the traditional pixel structure or the traditional image processor reading and signal processing method. The column parallel control method can achieve accurate control of the gain mode selection of each pixel.

[0102] Optionally, embodiments of this application also provide a camera module including the above-mentioned image sensor. This camera module can perform pixel-by-pixel modulation during the implementation of the TCG-HDR function, effectively ensuring the imaging effect of the output image.

[0103] Optionally, embodiments of this application also provide an electronic device, which includes the camera module described in the above embodiments. This electronic device can be a terminal or other devices besides a terminal. For example, the electronic device can be a mobile phone, tablet computer, laptop computer, PDA, in-vehicle electronic device, mobile internet device (MID), augmented reality (AR) / virtual reality (VR) device, robot, wearable device, ultra-mobile personal computer (UMPC), netbook, or personal digital assistant (PDA), etc. It can also be a server, network attached storage (NAS), personal computer (PC), television set (TV), ATM, or self-service machine, etc. Embodiments of this application do not impose specific limitations.

[0104] The electronic device in this application embodiment can be a device with an operating system. This operating system can be Android, iOS, or other possible operating systems; this application embodiment does not specifically limit the specific operating system used.

[0105] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element. Furthermore, it should be noted that the scope of the methods and apparatuses in the embodiments of this application is not limited to performing functions in the order shown or discussed, but may also include performing functions substantially simultaneously or in the reverse order, depending on the functions involved. For example, the described methods may be performed in a different order than described, and various steps may be added, omitted, or combined. Additionally, features described with reference to certain examples may be combined in other examples.

[0106] Through the above description of the embodiments, those skilled in the art can clearly understand that the methods of the above embodiments can be implemented by means of software plus necessary general-purpose hardware platforms. Of course, they can also be implemented by hardware, but in many cases the former is a better implementation method. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, can be embodied in the form of a computer software product. This computer software product is stored in a storage medium (such as ROM / RAM, magnetic disk, optical disk) and includes several instructions to cause a terminal (which may be a mobile phone, computer, server, or network device, etc.) to execute the methods described in the various embodiments of this application.

[0107] The embodiments of this application have been described above with reference to the accompanying drawings. However, this application is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of this application without departing from the spirit and scope of the claims, and all of these forms are within the protection scope of this application.

Claims

1. An image sensor, characterized by, The sensor comprises: a pixel array, a conversion gain selection module, and a conversion gain signal buffer and driving module; the pixel array comprises N rows of pixel units and M columns of pixel units, N pixel units in the same column are connected with the conversion gain signal buffer and driving module through a first connecting line, N pixel units in the same column are connected with the conversion gain selection module through a second connecting line, and M and N are positive integers; the conversion gain selection module is configured to generate a conversion gain selection table according to pixel signals output by the pixel array, the conversion gain selection table comprises conversion gain mode selection signals corresponding to each pixel unit, and the conversion gain mode selection signals in the conversion gain selection table are sorted according to the arrangement of the pixel array; the conversion gain signal buffer and driving module is configured to read the conversion gain mode selection signals corresponding to each pixel unit from the conversion gain selection table row by row, and send the conversion gain mode selection signals to the corresponding pixel units; the conversion gain selection module comprises a first comparator, a second comparator, and a conversion gain indicator, and the conversion gain indicator is in communication connection with the first comparator and the second comparator respectively; the first comparator is configured to compare the pixel signals corresponding to each pixel unit with a first preset threshold signal to obtain first comparator output signals corresponding to each pixel unit; the second comparator is configured to compare the pixel signals corresponding to each pixel unit with a second preset threshold signal to obtain second comparator output signals corresponding to each pixel unit; the conversion gain indicator is configured to buffer the first comparator output signals and the second comparator output signals, and generate the conversion gain selection table according to the first comparator output signals and the second comparator output signals; alternatively, the conversion gain selection module comprises an independent image signal processor outside the image sensor; the independent image signal processor is configured to perform pixel-by-pixel analysis on the pixel signals output by the pixel array according to a stored program algorithm to obtain the conversion gain mode selection signals corresponding to each pixel unit; the conversion gain selection table is generated according to the conversion gain mode selection signals corresponding to each pixel unit; the sensor further comprises an interface module in communication connection with the conversion gain signal buffer and driving module and the pixel array respectively; the interface module is configured to transmit the pixel signals output by the pixel array to the independent image signal processor, and receive the conversion gain mode selection signals corresponding to each pixel unit transmitted by the independent image signal processor.

2. The image sensor of claim 1, wherein, the first comparator is specifically configured to: output a first high-level output signal as the first comparator output signal corresponding to the pixel unit in the case where the pixel signal is greater than the first preset threshold signal; output a first low-level output signal as the first comparator output signal corresponding to the pixel unit in the case where the pixel signal is less than or equal to the first preset threshold signal; the second comparator is specifically configured to: output a second high-level output signal as the second comparator output signal corresponding to the pixel unit in the case where the pixel signal is greater than the second preset threshold signal; and output a second low-level output signal as the second comparator output signal corresponding to the pixel unit in the case where the pixel signal is less than or equal to the second preset threshold signal. In a case where the pixel signal is greater than the second preset threshold signal, the second comparator output signal corresponding to the pixel unit is a second high-level output signal; In a case where the pixel signal is less than or equal to the second preset threshold signal, the second comparator output signal corresponding to the pixel unit is a second low-level output signal.

3. The image sensor of claim 2, wherein, The conversion gain indicator is specifically used for: In a case where the first comparator output signal is a first high-level output signal and the second comparator output signal is a second high-level output signal, a gain mode selection signal of the pixel unit is a low gain mode selection signal; In a case where the first comparator output signal is a first low-level output signal and the second comparator output signal is a second high-level output signal, the gain mode selection signal of the pixel unit is a medium gain mode selection signal; In a case where the first comparator output signal is a first high-level output signal and the second comparator output signal is a second low-level output signal, the gain mode selection signal of the pixel unit is a low gain mode selection signal; In a case where the first comparator output signal is a first low-level output signal and the second comparator output signal is a second low-level output signal, the gain mode selection signal of the pixel unit is a high gain mode selection signal.

4. The image sensor of claim 1, wherein, The pixel array further comprises a signal reading module, and N pixel units in a same column are connected with the signal reading module through the second connection line. The signal reading module is configured to convert the pixel signal output by each pixel unit into an analog signal and transmit the analog signal to the conversion gain selection module.

5. A sensor architecture based on the image sensor of any of the preceding claims 1-4, characterized in that, The image sensor comprises: a pixel layer and a circuit layer; the pixel layer comprises a first bonding area and a pixel array, and the pixel array is in communication connection with the first bonding area; the circuit layer comprises a second bonding area, a conversion gain selection module, and a conversion gain signal buffer and driving module, the second bonding area is in communication connection with the conversion gain selection module and the conversion gain signal buffer and driving module respectively, and the first bonding area is in bonding connection with the second bonding area.

6. An image capture module, comprising: The image sensor comprises any one of claims 1-4.

7. An electronic device, comprising: The camera module comprises the image sensor of claim 6.

Images