Image sensor and reading control method thereof

Abstract

The application provides an image sensor and a reading control method thereof. The image sensor comprises a pixel array and a row selection control line. The pixel array comprises a plurality of pixel units arranged in a Bayer array. Part of the pixel units in the pixel array are arranged as a pair of focus photosensitive pixel units. The output value of the focus photosensitive pixel unit in the pair of focus photosensitive pixel units is used for focus control. The row selection control line receives a control signal and controls the selection of the pixel units in the row to be read for reading out the pixel signal. The row selection control line comprises a first group of row selection control lines and a second group of row selection control lines. The pixel array comprises a focus pixel row. The first group of row selection control lines is used for controlling the non-focus photosensitive pixel units in the focus pixel row to read out the pixel signal. The second group of row selection control lines is used for controlling the pair of focus photosensitive pixel units in the focus pixel row to read out the pixel signal. The application improves the phase focus performance and also improves the frame rate of pixel processing.

Description

Technical Field

[0001] This invention relates to image signal control technology, and in particular to an image sensor and its readout control method. Background Technology

[0002] Image sensors are used in a variety of electronic devices and products, such as digital cameras, video surveillance equipment, facial recognition, drones, and other products, to capture and recognize images.

[0003] In existing photography technologies, various optimization schemes are needed to improve phase detection autofocus technology, the most commonly used being the Bayer pixel array, such as... Figure 1 As shown in the diagram, G represents Green, R represents Red, and B represents Blue. Because the human eye is most sensitive to green, two Gs are used in the 2x2 pixel array.

[0004] for Figure 1 The circuit diagram of the Bayer array shown is as follows: Figure 2 As shown, four photodiodes correspond to three color filters. The signals of the photodiodes are transmitted to node FD through the TX series transmission tube. The reset transistor rst is used to reset the signal. Finally, the control signal rowsel controls the pixel selection transistor rs to perform row selection, thereby outputting pixel information.

[0005] However, when phase focusing technology is inserted into the current ordinary Bayer array, the phase focusing performance is relatively poor. Therefore, it is urgent to solve this technical defect. Summary of the Invention

[0006] In view of the shortcomings of the prior art described above, the purpose of this invention is to provide an image sensor and its readout control method to solve the problem of relatively poor focusing performance in the prior art.

[0007] To achieve the above and other related objectives, the present invention provides an image sensor, the image sensor comprising:

[0008] A pixel array includes multiple pixel units arranged in a Bayer array, each pixel unit including pixels of the same color arranged in a 2×2 structure; some pixel units in the pixel array are configured as focus-sensing pixel unit pairs, wherein each focus-sensing pixel unit pair includes two focus-sensing pixel units, each focus-sensing pixel unit is at least partially occluded, and the occluded areas of the focus-sensing pixel units in each focus-sensing pixel unit pair are complementary, so as to obtain the output value of the focus-sensing pixel unit in the focus-sensing pixel unit pair respectively, and perform focus control based on the output value;

[0009] The row selection control line receives control signals and selects the pixel units of the row to be read according to the control signals to read the pixel signals; the row selection control line includes a first set of row selection control lines and a second set of row selection control lines.

[0010] The pixel array includes a focus pixel row in which the focus photosensitive pixel unit pairs are provided. The first set of row selection control lines is used to control the non-focus photosensitive pixel units in the focus pixel row to read out pixel signals. The second set of row selection control lines is used to control the focus photosensitive pixel unit pairs in the focus pixel row to read out pixel signals.

[0011] Preferably, the focus-sensing pixel units in the focus-sensing pixel unit pair are spaced an odd number of rows apart.

[0012] Preferably, the focusing photosensitive pixel unit is formed by replacing the blue or red pixels in the Bayer array with green pixels.

[0013] Preferably, the focusing photosensitive pixel unit occupies 3% of the pixel array.

[0014] Preferably, the row selection control lines of the Nth row of pixels and the (N-2)th row of pixels in the focus-sensing pixel unit pair are symmetrically arranged, where N is a positive integer greater than or equal to 2.

[0015] Preferably, the (N-2)th row of pixels is provided with the first set of row selection control lines and the second set of row selection control lines;

[0016] In the (N-2)th pixel row, the first set of row selection control lines is used to control the readout of pixel signals of pixel units located in the same column as the non-focus photosensitive pixel units in the Nth pixel row, and the second set of row selection control lines is used to control the readout of pixel signals of pixel units located in the same column as the focus photosensitive pixel units in the Nth pixel row.

[0017] Preferably, the first group of row selection control lines outputs a first control signal to the Nth pixel row and the (N-2)th pixel row to control the off-focus photosensitive pixel units in the Nth and (N-2)th pixel rows to read out pixel signals; the second group of row selection control lines outputs a second control signal to the (N-2)th pixel row to control the pixel units in the (N-2)th pixel row that are located in the same column as the photosensitive pixel units in the Nth pixel row to read out pixel signals; the second group of row selection control lines outputs a third control signal to the Nth pixel row to control the photosensitive pixel units in the Nth pixel row to read out pixel signals.

[0018] Preferably, the image sensor includes a normal operating mode and a merge readout mode;

[0019] In the normal operating mode, the first set of row selection control lines is used to control the off-focus photosensitive pixel unit to read out pixel signals, and the second set of row selection control lines is used to control the focus photosensitive pixel unit to read out pixel signals.

[0020] In the merge readout mode, the focus pixel row does not read out pixel signals, and the pixel signals of adjacent pixel units of the same color located in the same pixel row and separated by one pixel unit are output through the same column of transmission control lines.

[0021] To achieve the above and other related objectives, the present invention also provides a reading control method for an image sensor, applicable to the aforementioned image sensor, the method comprising the following steps:

[0022] Control the pixel array to enter focus mode;

[0023] The system receives output control signals from the digital control circuit to control the selection of pixel units in the row to be read for reading pixel signals; the row selection control lines include a first set of row selection control lines and a second set of row selection control lines.

[0024] The row selection control line controls the focus pixel row where the focus photosensitive pixel unit is set to obtain the output value of the focus photosensitive pixel unit aligning with the pixel unit; wherein, the first region of one focus photosensitive pixel unit in the focus pixel row is controlled to read out the pixel signal and use it as the first output value; the second region of another focus photosensitive pixel unit in the focus pixel row is controlled to read out the pixel signal and use it as the second output value; the first region and the second region are complementary regions;

[0025] Focusing control is performed based on the first output value and the second output value.

[0026] Preferably, the focus control based on the first output value and the second output value includes:

[0027] A first phase value is generated based on the first output value;

[0028] A second phase value is generated based on the second output value;

[0029] Focusing control is performed based on the first phase value and the second phase value.

[0030] Preferably, the method further includes:

[0031] The first set of row selection control lines is used to control the pixel units in the (N-2)th pixel row that are located in the same column as the off-focus photosensitive pixel units in the Nth pixel row to read out the pixel signals;

[0032] The second set of row selection control lines is used to control the pixel units in the (N-2)th pixel row that are located in the same column as the focusing photosensitive pixel units in the Nth pixel row to read out the pixel signals.

[0033] Preferably, the method further includes:

[0034] Control the pixel array to enter the merge readout mode;

[0035] The readout channel of the pixel signal of the focused pixel row is closed, and the pixel signals of adjacent same-color pixel units located in the same pixel row and separated by one pixel unit are output through the same column of transmission control lines. The same column of output control lines is one of the columns where the adjacent same-color pixel units are located.

[0036] As described above, the image sensor and its reading control method of the present invention have the following beneficial effects:

[0037] The image sensor of this invention, through an optimized pixel array layout and the use of two sets of row selection control lines, achieves controlled selection of pixel units in the rows to be read for pixel signal readout. The pixel unit layout in the pixel array of this invention allows for a larger pixel range and photosensitive area, and since the four pixels in each pixel unit sample the same control signal, pixel processing speed can be greatly improved. Simultaneously, the use of a Bayer array arrangement significantly enhances phase detection autofocus performance. Furthermore, the adoption of lateral binning readout technology further improves the frame rate of pixel processing. Attached Figure Description

[0038] Figure 1 The diagram shows a layout schematic of a Bayer array in the prior art.

[0039] Figure 2 The diagram shown is a schematic of the circuit structure of a Bayer array in the prior art.

[0040] Figure 3 The diagram shows the layout of pixel units in the pixel array of this invention.

[0041] Figure 4 The diagram shown is a schematic representation of the layout structure of an image sensor in one embodiment of the present invention.

[0042] Figure 5 The diagram shows the layout structure of the image sensor in another embodiment of the present invention.

[0043] Figure 6 Displayed as Figure 5 Timing diagram of the image sensor in normal operating mode.

[0044] Figure 7 Displayed as Figure 5 Timing diagram of the image sensor in merge readout mode. Detailed Implementation

[0045] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention.

[0046] Please see Figures 3-7 It should be noted that the illustrations provided in this embodiment are only schematic representations of the basic concept of the present invention. Therefore, the drawings only show the components related to the present invention and are not drawn according to the actual number, shape and size of the components in the actual implementation. In the actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.

[0047] This invention samples two control signals and controls the pixel units separately through timing, realizing the control functions of lateral binning and phase detection autofocus, improving the frame rate, while improving the performance of phase detection autofocus (PDAF) and increasing the dynamic range.

[0048] Based on the above technical concept, the present invention proposes a technical solution for an image sensor and its reading control method to solve the problems existing in the prior art. The present invention will provide a detailed description of the technical concept and technical solution through the following embodiments.

[0049] Example 1:

[0050] like Figure 4 This is a schematic diagram of the layout structure of the image sensor in an embodiment of the present invention. The embodiments of the present invention are combined with... Figure 4 The image sensor of the present invention will be described in detail.

[0051] Image sensors include pixel arrays and row selection control lines;

[0052] The pixel array includes multiple pixel units arranged in a Bayer array, each pixel unit including pixels of the same color arranged in a 2×2 structure; some pixel units in the pixel array are set as focus-sensing pixel unit pairs, wherein each focus-sensing pixel unit pair includes two focus-sensing pixel units, each focus-sensing pixel unit is at least partially occluded, and the occluded areas of the two focus-sensing pixel units in each focus-sensing pixel unit pair are complementary, so as to obtain the output value of the focus-sensing pixel unit in the focus-sensing pixel unit pair respectively, and perform focus control based on the output value;

[0053] The row selection control lines receive control signals to control the selection of pixel units in the row to be read for pixel signal reading; the row selection control lines include a first set of row selection control lines and a second set of row selection control lines.

[0054] The pixel array includes a focus pixel row with focus-sensing pixel unit pairs. A first set of row selection control lines is used to control the non-focus-sensing pixel units in the focus pixel row to read out pixel signals, and a second set of row selection control lines is used to control the focus-sensing pixel unit pairs in the focus pixel row to read out pixel signals.

[0055] Specifically, the pixel array of the present invention includes 8×8 pixel units arranged in a Bayer array, each pixel unit as follows: Figure 3 As shown, pixels arranged in a 2×2 structure and having the same color are green (G), red (R), and blue (B). The pixel array of this invention has an overall array height of symmetry, and the transistors in the pixel units are all NMOS transistors, which have a relatively fast transmission speed. Therefore, a high-level enable is required during the control process.

[0056] Specifically, in this invention, the focusing photosensitive pixel units in the focusing photosensitive pixel unit pair are spaced an odd number of rows apart. In this embodiment, the pixel unit corresponding to the 2nd row, 3rd column (Row2, Column3) and the pixel unit corresponding to the 2nd row, 7th column (Row2, Column7) in the pixel array are set as a focusing photosensitive pixel unit pair. During phase focusing, the two focusing photosensitive pixel units are partially obscured, for example... Figure 4In the diagram, the left half of the first focusing photosensitive pixel unit corresponding to Row 2, Column 3 is obscured, and the right half of the second focusing photosensitive pixel unit corresponding to Row 2, Column 7 is obscured. The obscured areas on the left and right sides of the first and second focusing photosensitive pixel units complement each other, resulting in the output values ​​of the focusing photosensitive units: a first output value and a second output value. Focus control is achieved using a first phase value generated from the first output value and a second phase value generated from the second output value. In other words, the first output value enables imaging of the right half of the focusing photosensitive pixel unit pair, and the second output value enables imaging of the left half. The difference between the first and second phase values ​​is used to perform phase shifting, achieving fast, one-step focusing.

[0057] In this embodiment of the invention, the occluded areas are complementary to the left half of one focusing photosensitive pixel unit and the right half of another focusing photosensitive pixel unit. As another implementation, the occluded areas may be the upper half of one focusing photosensitive pixel unit and the lower half of another focusing photosensitive pixel unit; or one-quarter of one focusing photosensitive pixel unit and three-quarters of another focusing photosensitive pixel unit.

[0058] The image sensor of this invention achieves pixel signal readout by controlling the selection of pixel units in the row to be read through an optimized pixel array layout and the use of two sets of row selection control lines. The pixel unit layout in the pixel array of this invention allows for a larger pixel range and photosensitive area, and since the four pixels in each pixel unit sample the same control signal, pixel processing speed can be greatly improved. Simultaneously, the use of a Bayer array arrangement significantly enhances the performance of phase-detection autofocus.

[0059] In the layout of the pixel array, this invention takes into account the good photosensitivity of green. Therefore, the focusing photosensitive pixel unit replaces the blue or red pixels in the Bayer array with green pixels, so that there are more photosensitive units with green pixels in the pixel array, thereby further improving the photosensitivity of the pixel array.

[0060] Because of the presence of focusing photosensitive pixel units, the color block settings of the focusing pixel row corresponding to the Nth row are different from those of the (N-2)th row of pixels. For example... Figure 4As shown, the color block settings for the second row (Row2) are different from those for the first row (Row0). Due to parasitic capacitance on the signal lines, it is necessary to maintain a consistent surrounding environment for each pixel unit. Therefore, to achieve better optimization control during pixel array readout, two sets of row selection control signals are set for both the Nth row (the focus pixel row) and the (N-2)th row. Furthermore, to further match each pixel row on the layout, as... Figure 5 As shown, two sets of row selection control signals are set for all pixel rows. In this invention, the first set of row selection control lines rs<0:7> and the second set of row selection control lines rsp<0:7> are used to control the two different color blocks in the same pixel row separately according to the mode requirements. Of course, optionally, two sets of row selection control lines can also be set on pixel rows that do not have focusing photosensitive pixel units. However, in actual signal control, only one set of row selection control lines is used to control the selection of the selected pixel row to read the pixel signal, while the other set of row selection control lines is left floating.

[0061] The first group of row selection controls corresponds to one control signal. Specifically, the first control signal dd_rs is transmitted to the first group of row selection control lines rs<0:7> corresponding to each pixel row. The second control signal dd_rsp <0> and the third control signal dd_rsp <1> The data is transmitted to the second set of row selection control lines rsp<0:7> corresponding to each pixel row.

[0062] Specifically, in this invention, the first set of row selection control lines rs receives the first control signal dd_rs, and sequentially controls the selection of off-focus photosensitive pixel units in the Nth and (N-2)th pixel rows to be read for pixel signal readout according to the first control signal dd_rs; the second set of row selection control lines rsp receives the second control signal dd_rsp. <0> And according to the second control signal dd_rsp <0> The control selects the pixel unit in the (N-2)th pixel row that is in the same column as the focus sensor pixel unit in the Nth pixel row for reading the pixel signal; the second group of row selection control lines rsp receives the third control signal dd_rsp. <1> And according to the third control signal dd_rsp <1> The control selects the focus-sensitive pixel unit in the Nth row of pixels to be read and reads the pixel signal.

[0063] In this invention, the row selection control lines of the Nth pixel row and the (N-2)th pixel row, which contain the focusing photosensitive pixel units, are symmetrically arranged, where N is a positive integer greater than or equal to 2. Specifically, in this embodiment, the layout is more closely matched by symmetrically distributing the row selection control lines (rs and rsp) of the 0th and 2nd rows. Alternatively, the row selection control lines of the 2nd and 4th pixel rows can also be symmetrically arranged.

[0064] The image sensor of the present invention includes a normal operating mode and a merge readout mode;

[0065] In normal operating mode, the first set of row selection control lines rs is used to control the off-focus photosensitive pixel units to read out pixel signals, and the second set of row selection control lines rsp is used to control the focus photosensitive pixel units to read out pixel signals.

[0066] In merge readout mode, the focus pixel row does not read out pixel signals, and the pixel signals of adjacent pixel units of the same color located in the same pixel row and separated by one pixel unit are output through the same column of transmission control bitline.

[0067] This invention, based on a first control signal, a second control signal, and a third control signal, controls the readout of pixel units in each row of pixels row by row through a first set of row selection control lines rs<0:7> and a second set of row selection control lines rsp<0:7>. In this embodiment, due to the presence of focusing photosensitive pixel units, to satisfy layout matching, the color block settings of the focusing pixel row corresponding to the Nth row are different from those of the (N-2)th row of pixels. Therefore, control is achieved through two different sets of row selection control signals. For other pixel rows, although two sets of control signals are also used for layout matching, since the first control signal of this row is the same and controls all pixel units in the same pixel row, either the rs control signal or the rsp control signal can be used directly.

[0068] More specifically, in normal working mode, the readout process for each row of pixels is as follows:

[0069] For the (N-2)th pixel row: the (N-2)th pixel row is provided with a first set of row selection control lines and a second set of row selection control lines; in the (N-2)th pixel row, the first set of row selection control lines is used to control the readout of pixel signals from pixel units located in the same column as the out-of-focus photosensitive pixel units in the Nth pixel row, and the second set of row selection control lines is used to control the readout of pixel signals from pixel units located in the same column as the photosensitive pixel units in the Nth pixel row. More specifically, in this embodiment of the invention, in the 0th pixel row (Row0), based on the first control signal dd_rs, the rs in the first set of row selection control lines <0> The off-focus photosensitive pixel units (the pixel units corresponding to columns 1, 2, 4, 5, 6, and 8) are controlled to read out pixel signals based on the second control signal dd_rsp. <0> In the second group of row selection control lines, rsp <0> Control the focus-sensing pixel units (the pixel units corresponding to Row0 / column3 and the pixel units corresponding to Row0 / column7) to read out pixel signals.

[0070] For the Nth pixel row: the Nth pixel row is provided with a first set of row selection control lines and a second set of row selection control lines; the first set of row selection control lines is used to control the non-focus photosensitive pixel units in the focused pixel row to read out pixel signals, and the second set of row selection control lines is used to control the focused photosensitive pixel units in the focused pixel row to read out pixel signals. More specifically, in this embodiment of the invention, the focused pixel row is the 2nd row (Row2), and based on the first control signal, the first set of row selection control lines rs <2> The off-focus photosensitive pixel units (pixel units corresponding to columns 1, 2, 4, 5, 6, and 8) are controlled to read out pixel signals based on the third control signal and the second group of row selection control lines rsp. <2> Control the focus-sensing pixel units (the pixel units corresponding to column3 and column7) to read out pixel signals.

[0071] For other rows (N-1 rows, N+1 rows, etc.): the first set of row selection control lines or the second set of row selection control lines control all pixel units in the corresponding pixel row to read out pixel signals. More specifically, in this embodiment of the invention, for the first pixel row (Row1), based on the first control signal, the first set of row selection control lines rs <1> Control all pixel units (pixel units corresponding to columns1-column8) to read out pixel signals.

[0072] More specifically, in the merge readout mode, the focus pixel row does not read out pixel signals, and the pixel signals of adjacent pixel units of the same color located in the same pixel row and separated by one pixel unit are output through the same column transmission control line; that is, except for the focus pixel not working, the corresponding columns 1 / column3, column 2 / column4, column 5 / column7, column 6 / column8 of other pixel rows can be horizontally binned, using a single signal for control and output; for example, when reading row 0, the pixel values ​​of the color blocks in column 6 / column8 are merged and read out in binning, and then the data after merging and reading out in binning can be selected to be output from column 6 or column 8 via the column-direction analog-to-digital converter (AD6 or AD8), leaving one idle analog-to-digital converter AD idle, so that during the column-direction data readout process, the pixels are sparse and the data is halved, thereby improving the frame rate.

[0073] The timing control in the specific normal working mode and the merged readout mode is as follows: Figure 6 As shown and Figure 7 As shown, it needs to be explained that... Figure 6 The dashed line represents that the corresponding signal at this timing can be either low or high, and both can achieve the technical solution of this case. Because the color blocks of the focused pixel PDAF and the pixel units to be merged differ during horizontal merging readout, it is necessary to control the second row (Row2) from effectively merging readout horizontally. Therefore, as shown... Figure 7 As shown, in merge readout mode, all signals in row 2 must be turned off. Two sets of row selection control lines are used to control the focus and non-focus pixel units respectively. This ensures that during horizontal merge readout of the pixel array, the focus pixel row cannot be opened, while other pixel rows can be merged and read out through the same column line. This halves the pixel value data of the resulting pixel unit, thus improving the frame rate.

[0074] In this invention, the focusing photosensitive pixel unit occupies 3% of the pixel array, which does not greatly reduce the number of pixels. That is, when reading out image information normally, there are fewer pixel units corresponding to phase focusing PDAF, but phase information can still be obtained. When reading out horizontally, phase information cannot be obtained, and one less row of pixel units is obtained when obtaining image information, but the frame rate can be greatly improved.

[0075] Example 2:

[0076] A reading control method for an image sensor, applicable to the image sensor described in Embodiment 1, the method comprising the following steps:

[0077] Control the pixel array to enter focus mode;

[0078] Receive the output control signal from the digital control circuit to control the selection of pixel units in the row to be read for reading pixel signal;

[0079] The row selection control line controls the focus pixel row where the focus photosensitive pixel unit is set to obtain the output value of the focus photosensitive pixel unit aligning with the pixel unit; wherein, the first region of one focus photosensitive pixel unit in the focus pixel row is controlled to read out the pixel signal and use it as the first output value; the second region of another focus photosensitive pixel unit in the focus pixel row is controlled to read out the pixel signal and use it as the second output value; the first region and the second region are complementary regions;

[0080] Focusing control is performed based on the first output value and the second output value.

[0081] In this embodiment, since the image sensor has been described in detail in Embodiment 1, it will not be described in detail again in this embodiment.

[0082] In focus mode, the image sensor readout control method of this invention controls the focus pixel row through two sets of row selection control lines, respectively, and performs focus control through the first output value and the second output value. The two sets of row selection control lines allow for individual control of the focus pixel row containing the focus photosensitive pixel unit.

[0083] In a preferred embodiment of the present invention, focusing control based on the first output value and the second output value includes:

[0084] Generate a first phase value based on the first output value;

[0085] A second phase value is generated based on the second output value;

[0086] Focusing control is performed based on the first phase value and the second phase value.

[0087] After obtaining the first output value and the second output value, the first phase value and the second phase value can be calculated and generated. The phase difference information between the first phase value and the second phase value can be converted into focus distance information. The position of the lens can be adjusted according to the focus distance information to achieve phase focusing, thus making the implementation of phase focusing detection simpler.

[0088] As a further limitation of this embodiment of the invention, the method also includes:

[0089] The first set of row selection control lines is used to control the readout of pixel signals for pixel units in the (N-2)th pixel row that are in the same column as the off-focus photosensitive pixel units in the Nth pixel row.

[0090] The second set of row selection control lines is used to control the readout of pixel signals from pixel units in the (N-2)th pixel row that are in the same column as the focusing photosensitive pixel unit in the Nth pixel row.

[0091] In this embodiment of the invention, during the readout control process, for both the focused pixel row and the non-focused pixel row for layout matching, the pixel signal is read out for the non-focused pixel column through the first set of row selection control lines, and the pixel signal is read out for the focused pixel column through the second set of row selection control lines.

[0092] As a preferred embodiment of the present invention, the method further includes:

[0093] Control the pixel array to enter merge readout mode;

[0094] The readout channel of the pixel signal of the focused pixel row is closed, and the pixel signals of adjacent pixel units of the same color located in the same pixel row and separated by one pixel unit are output through the same column of transmission control lines. The same column of transmission control lines is one of the columns where the adjacent pixel units of the same color are located.

[0095] When entering the merge readout mode, this invention requires that the readout channel of the pixel signal of the focused pixel row be closed because the color blocks of the PDAF of the focused pixel are different from those of the pixel unit to be merged. Instead, the pixel signals of adjacent pixel units of the same color in the same row of the non-focused pixel row, separated by one pixel unit, are output through one column line, while the other column line is left idle. This results in the number of columns being merged and the data being halved during the data readout process in the column direction, thereby improving the frame rate.

[0096] In summary, this invention achieves controlled selection of pixel units in the rows to be read by optimizing the layout of the pixel array and sampling two sets of row selection control lines. The pixel unit layout in the pixel array of this invention allows for a larger pixel range and photosensitive area, and since the four pixels in each pixel unit sample the same control signal, it can greatly improve pixel processing speed. Simultaneously, the use of a Bayer array arrangement significantly improves phase detection autofocus performance. Furthermore, the use of lateral merging readout technology further enhances the frame rate of pixel processing. Therefore, this invention effectively overcomes the various shortcomings of existing technologies and has high industrial applicability.

[0097] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in the present invention should still be covered by the claims of the present invention.

Claims

1. An image sensor, characterized in that, The image sensor includes: A pixel array includes multiple pixel units arranged in a Bayer array, each pixel unit comprising pixels of the same color arranged in a 2×2 structure; a portion of the pixel units in the pixel array are configured as focus-sensing pixel unit pairs, wherein the focus-sensing pixel unit pairs replace blue or red pixels in the Bayer array with green pixels; wherein each focus-sensing pixel unit pair comprises two focus-sensing pixel units, each focus-sensing pixel unit being at least partially obscured, and the obscured areas of the focus-sensing pixel units in each focus-sensing pixel unit pair being complementary, so as to obtain the output value of the focus-sensing pixel unit in the focus-sensing pixel unit pair respectively, and perform focus control based on the output value; a row selection control line receives a control signal and controls the selection of pixel units in the row to be read for pixel signal readout according to the control signal; the row selection control line includes a first set of row selection control lines and a second set of row selection control lines. The pixel array includes a focus pixel row in which the focus photosensitive pixel unit pair is provided. The first set of row selection control lines is used to control the non-focus photosensitive pixel unit in the focus pixel row to read out the pixel signal. The second set of row selection control lines is used to control the focus photosensitive pixel unit pair in the focus pixel row to read out the pixel signal. In the normal operating mode of the image sensor, the first set of row selection control lines is used to control the off-focus photosensitive pixel units to read out pixel signals, and the second set of row selection control lines is used to control the focus photosensitive pixel units to read out pixel signals. In the image sensor merge readout mode, the focus pixel row does not read out pixel signals, and the pixel signals of adjacent pixel units of the same color located in the same pixel row and separated by one pixel unit are output through the same column transmission control line.

2. The image sensor according to claim 1, characterized in that, The focus-sensing pixel units in the focus-sensing pixel unit pair are spaced an odd number of rows apart.

3. The image sensor according to claim 1, characterized in that, The focusing photosensitive pixel unit occupies 3% of the pixel array.

4. The image sensor according to claim 1, characterized in that, The row selection control lines of the Nth row of pixels and the (N-2)th row of pixels, which are configured with the focusing photosensitive pixel unit pair, are symmetrically arranged, where N is a positive integer greater than or equal to 2.

5. The image sensor according to claim 4, characterized in that, The (N-2)th row of pixels is provided with the first set of row selection control lines and the second set of row selection control lines; In the (N-2)th pixel row, the first set of row selection control lines is used to control the pixel units located in the same column as the off-focus photosensitive pixel units in the Nth pixel row to read out pixel signals, and the second set of row selection control lines is used to control the pixel units located in the same column as the focus photosensitive pixel units in the Nth pixel row to read out pixel signals.

6. The image sensor according to claim 5, characterized in that, The first group of row selection control lines outputs a first control signal to the Nth pixel row and the (N-2)th pixel row to control the off-focus photosensitive pixel units in the Nth pixel row and the (N-2)th pixel row to read out pixel signals; The second group of row selection control lines outputs a second control signal to the (N-2)th pixel row to control the pixel units in the (N-2)th pixel row that are located in the same column as the focusing photosensitive pixel units in the Nth pixel row to read out pixel signals; The second group of row selection control lines outputs a third control signal to the Nth row of pixels to control the focus-sensing pixel units in the Nth row of pixels to read out pixel signals.

7. A method for reading and controlling an image sensor, applicable to the image sensor according to any one of claims 1-6, characterized in that, The method includes the following steps: Control the pixel array to enter focus mode; Receive the output control signal from the digital control circuit to control the selection of pixel units in the row to be read for reading pixel signal; The row selection control line controls the focus pixel row where the focus photosensitive pixel unit is set to obtain the output value of the focus photosensitive pixel unit aligning with the pixel unit; wherein, the first region of one focus photosensitive pixel unit in the focus pixel row is controlled to read out the pixel signal and use it as the first output value; the second region of another focus photosensitive pixel unit in the focus pixel row is controlled to read out the pixel signal and use it as the second output value; the first region and the second region are complementary regions; Focusing control is performed based on the first output value and the second output value.

8. The image sensor readout control method according to claim 7, characterized in that, The focus control based on the first output value and the second output value includes: A first phase value is generated based on the first output value; A second phase value is generated based on the second output value; Focusing control is performed based on the first phase value and the second phase value.

9. The image sensor readout control method according to claim 7 or 8, characterized in that, The focusing photosensitive pixel unit is set in the (N-2)th pixel row and the Nth pixel row, where N is a positive integer greater than or equal to 2; the method further includes: The first set of row selection control lines is used to control the pixel units in the (N-2)th pixel row that are located in the same column as the off-focus photosensitive pixel units in the Nth pixel row to read out the pixel signals; The second set of row selection control lines is used to control the pixel units in the (N-2)th pixel row that are located in the same column as the focusing photosensitive pixel units in the Nth pixel row to read out the pixel signals.

10. The image sensor readout control method according to claim 9, characterized in that, The method further includes: Control the pixel array to enter the merge readout mode; The readout channel of the pixel signal of the focused pixel row is closed, and the pixel signals of adjacent same-color pixel units located in the same pixel row and separated by one pixel unit are output through the same column of transmission control lines. The same column of transmission control lines is one of the columns where the adjacent same-color pixel units are located.

Images