Image sensor and signal reading control method thereof

Abstract

The application provides an image sensor and a signal reading control method thereof. The image sensor comprises a pixel array and a row selection control line. The focusing photosensitive pixel unit part in the focusing pixel column of the pixel array is shielded to obtain an output value and perform focusing control based on the output value. The row selection control line receives a row selection control signal and controls the selection of the pixel unit of the row to be read out to read out the pixel signal according to the row selection control signal. In a normal working mode, the image sensor reads out each pixel row in the pixel array row by row. In a combined reading mode, at least two pixel rows spaced by odd rows simultaneously receive the row selection control signal, and the focusing photosensitive pixel unit in the focusing pixel column and the non-focusing photosensitive pixel unit spaced by odd rows simultaneously receiving the row selection control signal correspond to one reading channel respectively, wherein one reading channel is opened and the other reading channel is closed. The application improves the phase focusing performance and 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 signal reading 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 signal reading control method to solve the problem of poor phase 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; wherein, the pixel array includes a focusing pixel column, in which some blue or red pixels are replaced with green pixels to form a focusing photosensitive pixel unit, and the focusing photosensitive pixel unit is partially obscured to obtain its output value, and focusing control is performed based on the output value;

[0009] The row selection control line receives the row selection control signal and controls the selection of pixel units in the row to be read out according to the row selection control signal.

[0010] The image sensor includes a normal operating mode and a merged readout mode; in the normal operating mode, the pixel rows in the pixel array are read out row by row; in the merged readout mode, at least two pixel rows with an odd number of rows between them simultaneously receive row selection control signals, and in the focusing pixel column, the focusing photosensitive pixel unit that simultaneously receives the row selection control signal and the non-focusing photosensitive pixel unit with an odd number of rows between them each correspond to a readout channel, with one readout channel open and the other readout channel closed.

[0011] Preferably, it further includes column lines for reading out the pixel signals of the pixel units in the row to be read, the column lines including a first column line and a second column line; in the focusing pixel column, the focusing photosensitive pixel unit is read out through the first column line, and the non-focusing photosensitive pixel units that are spaced an odd number of rows away from the focusing photosensitive pixel unit are read out through the second column line.

[0012] Preferably, every two focusing photosensitive pixel units located in the same pixel row form a focusing photosensitive pixel unit pair, and the occluded areas of the focusing photosensitive pixel units in each focusing photosensitive pixel unit pair are complementary, so as to obtain the output value of each focusing photosensitive pixel unit in the focusing photosensitive pixel unit pair respectively, and perform focusing control based on the output value.

[0013] Preferably, the two focus-sensing pixel units in the focus-sensing pixel unit pair are spaced an odd number of rows apart.

[0014] Preferably, the focusing photosensitive pixel unit occupies 3% of the pixel array.

[0015] Preferably, in each pixel column, one of the two pixel units that simultaneously receive the row selection control signal is read out through the first column line, and the other pixel unit is read out through the second column line.

[0016] Preferably, the row selection control lines include a first set of row selection control lines and a second set of selection control lines;

[0017] The pixel array includes a focus pixel row in which the focus photosensitive pixel unit is disposed; 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 in the focus pixel row to read out the pixel signal.

[0018] 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.

[0019] In the merge readout mode, the focus pixel row does not read out pixel signals. The four pixel units in the Kth row and Mth column, the Kth row and M+2th column, the K+2th row and Mth column, and the K+2th row and M+2th column simultaneously receive row selection control signals. Among these four pixel units, adjacent pixel units located in the same pixel row and separated by one pixel unit are merged and read out through the same column line, while adjacent pixel units located in the same pixel column and separated by one pixel unit are read out through different column lines. Here, K and M are both positive integers.

[0020] Preferably, the row selection control lines of the Nth row of pixels and the (N-2)th row of pixels, where the focusing photosensitive pixel unit is located, are symmetrically arranged, where N is a positive integer greater than or equal to 2.

[0021] 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;

[0022] 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.

[0023] 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, so as to control the off-focus photosensitive pixel units in the Nth pixel row and the (N-2)th pixel row to read out the pixel signal respectively;

[0024] 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;

[0025] 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.

[0026] To achieve the above and other related objectives, the present invention also provides a signal readout control method for an image sensor, the method comprising at least the following steps:

[0027] Control the pixel array to enter focus mode;

[0028] Receive control signals and control the pixel units of the row to be read to read out pixel signals according to the control signals;

[0029] The row selection control line is used to control the first region of a focusing photosensitive pixel unit in the focusing pixel column to read out the pixel signal and output the first output value through the first column line;

[0030] The row selection control line is used to control the second region of another focusing photosensitive pixel unit in the focusing pixel column to read out the pixel signal and output the second output value through the first column line; the second region and the first region form a complementary region of the focusing photosensitive pixel unit;

[0031] Focusing control is performed based on the first output value and the second output value.

[0032] Preferably, the focus control based on the first output value and the second output value includes:

[0033] A first phase value is generated based on the first output value;

[0034] A second phase value is generated based on the second output value;

[0035] Focusing control is performed based on the first phase value and the second phase value.

[0036] Preferably, the method further includes:

[0037] The pixel array is controlled to enter a normal working mode, and the row selection control line sequentially outputs row selection control signals to each pixel row so that the pixel rows in the pixel array are read out one by one;

[0038] The pixel array is controlled to enter a merge readout mode, where every two rows of pixels spaced an odd number of rows simultaneously receive row selection control signals; in a pixel column containing a focusing photosensitive pixel unit, the focusing photosensitive pixel unit is controlled to open through the channel readout from the first column line, while the non-focusing photosensitive pixel units spaced an odd number of rows away from the focusing photosensitive pixel unit are controlled to close through the channel readout from the second column line; or...

[0039] In a pixel column with a focusing photosensitive pixel unit, the focusing photosensitive pixel unit is turned off through the channel read out from the first column line, and the non-focusing photosensitive pixel unit, which is spaced an odd number of rows away from the focusing photosensitive pixel unit, is turned on through the channel read out from the second column line.

[0040] Preferably, two sets of row selection control lines are provided, wherein 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 non-focus photosensitive pixel units in the Nth pixel row to read out 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 focus photosensitive pixel units in the Nth pixel row to read out pixel signals.

[0041] Preferably, in the merge readout mode, the readout channel of the pixel signal of the focused pixel row is closed, and the four pixel units in the Kth row M column, the Kth row M+2 column, the K+2 row M column, and the K+2 row M+2 column simultaneously receive the row selection control signal. Among the four pixel units, adjacent pixel units located in the same pixel row and separated by one pixel unit are merged and read out through the same column line, and adjacent pixel units located in the same pixel column and separated by one pixel unit are read out through the first column line and the second column line, respectively.

[0042] As described above, the image sensor and its signal reading control method of the present invention have the following beneficial effects:

[0043] The image sensor of the present invention, through an optimized pixel array layout, controls the selection of pixel units to be read from the row to be read simultaneously by receiving control signals. The pixel unit layout in the pixel array of the present invention can achieve a larger pixel range and photosensitive area, and the four pixels included in the pixel unit use the same control signal, which can greatly improve the pixel processing speed and further improve the frame rate of pixel processing. Attached Figure Description

[0044] Figure 1 The diagram shows a layout schematic of a Bayer array in the prior art;

[0045] Figure 2 The diagram shows a schematic of the circuit structure of a Bayer array in the prior art.

[0046] Figure 3 The diagram shows the layout of pixel units in an embodiment of the present invention.

[0047] Figure 4 The diagram shows a layout structure of an image sensor in one embodiment of the present invention.

[0048] Figure 5 Displayed as Figure 4 The timing diagram shown is a readout from the image sensor in normal operating mode.

[0049] Figure 6 Displayed as Figure 4 The image sensor's timing diagram shown is from the longitudinal merging readout mode.

[0050] Figure 7 This is a schematic diagram of the image sensor layout structure in another embodiment of the present invention;

[0051] Figure 8 Displayed as Figure 7 The timing diagram shown is for PDAF being turned off during lateral readout of the image sensor.

[0052] Figure 9 Displayed as Figure 7 The timing diagram shown is for PDAF to be turned on during horizontal readout of the image sensor. Detailed Implementation

[0053] 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.

[0054] Please see Figures 3-8 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.

[0055] This invention employs one or two sets of control signals to control pixel units separately through timing, and then uses two columns of lines to achieve horizontal / vertical binning and phase detection autofocus control functions, thereby improving phase detection autofocus (PDAF) performance and increasing dynamic range.

[0056] Based on the above technical concept, the present invention proposes a technical solution for an image sensor and its signal reading and 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.

[0057] Example 1:

[0058] 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.

[0059] The image sensor proposed in this invention includes:

[0060] 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; wherein, the pixel array includes a focusing pixel column, in which some blue or red pixels are replaced with green pixels to form a focusing photosensitive pixel unit, and the focusing photosensitive pixel unit is partially occluded to obtain its output value, and focus control is performed based on the output value.

[0061] The row selection control line receives the row selection control signal and selects the pixel unit of the row to be read according to the row selection control signal to read the pixel signal;

[0062] The image sensor includes a normal operating mode and a merged readout mode. In the normal operating mode, pixel rows in the pixel array are read out row by row. In the merged readout mode, at least two pixel rows with an odd number of rows between them simultaneously receive row selection control signals. In the focus pixel column, the focus photosensitive pixel unit that simultaneously receives the row selection control signal and the non-focus photosensitive pixel unit with an odd number of rows between them each correspond to a readout channel. One readout channel is open and the other readout channel is closed.

[0063] In this invention, due to the good photosensitivity of green, some blue or red pixels in the focusing pixel column are replaced with green pixels to form focusing photosensitive pixel units. This results in more photosensitive units with green pixels in the pixel array, further improving the photosensitivity of the pixel array. Specifically, the pixel array of this 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.

[0064] The image sensor of this invention, through an optimized pixel array layout, controls the selection of pixel units in the rows to be read by simultaneously receiving control signals. In normal operation mode, pixel rows are read out one by one. In merged readout mode, at least two pixel rows with an odd number of rows between them simultaneously receive row selection control signals, allowing at least two rows to be read out simultaneously, further improving the frame rate of pixel processing. Since the focusing photosensitive pixel unit is formed by replacing some blue or red pixels with green pixels, the color blocks between pixel rows that simultaneously receive control signals are different. Therefore, two readout channels are used to output pixel signals separately. For other pixel rows that simultaneously receive control signals and have the same color blocks, another readout channel can be left idle or not set up, thus not affecting the frame rate of pixel processing of this invention. In addition, the pixel unit layout in the pixel array of this invention can achieve a larger pixel range and photosensitive area, and the four pixels in a pixel unit use the same control signal, which can greatly improve the pixel processing speed. At the same time, the Bayer array arrangement can significantly improve the performance of phase focusing.

[0065] As a further limitation of the present invention, every two focusing photosensitive pixel units located in the same pixel row form a focusing photosensitive pixel unit pair, and the occluded areas of the focusing photosensitive pixel units in each focusing photosensitive pixel unit pair are complementary, so as to obtain the output value of each focusing photosensitive pixel unit in the focusing photosensitive pixel unit pair respectively, and perform focusing control based on the output value.

[0066] 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.

[0067] Furthermore, at least two rows of pixels spaced at odd intervals simultaneously receive the row selection control signal. The odd intervals can be one row, three rows, etc. In other embodiments of the present invention, the row selection control signal can also be received simultaneously by three rows of pixels spaced at odd intervals, which can also achieve the technical effect of improving the frame rate.

[0068] Specifically, in this invention, the focusing photosensitive pixel units in the focusing photosensitive pixel unit pair are spaced an odd number of columns 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 4 In 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.

[0069] Due to the presence of focusing photosensitive pixel units, in order to better optimize and control the signal readout of the image sensor, the image sensor of the present invention further includes column lines for reading the pixel signals of the pixel units in the rows to be read. The column lines include a first column line and a second column line. In the focusing pixel column, the focusing photosensitive pixel units are read out through the first column line, and the non-focusing photosensitive pixel units that are spaced an odd number of rows away from the focusing photosensitive pixel units are read out through the second column line.

[0070] In this invention, pixel signals are read out via two columns of lines, allowing for independent control of the focusing photosensitive pixel units in the focusing pixel column and the non-focusing photosensitive pixel units spaced an odd number of rows apart from the focusing photosensitive pixel units. That is, they are read out separately via different columns of lines. The odd number of rows between the columns can be one row, three rows, etc., but must be consistent with the color of the focusing photosensitive pixel unit before it was replaced by a green pixel.

[0071] like Figure 4 As shown, the color block settings for the second row (Row2) of pixels are different from those for the first row (Row0). Because of parasitic capacitance on the signal lines, it is necessary to maintain a consistent environment around each pixel unit. Therefore, to better optimize control during pixel array readout, a row selection control line is set for each pixel row, and two column lines are set for each focused pixel column. For example... Figure 4 In the image, the two column lines of column 3 are Bitline3_0 and Bitline3_1; the two column lines of column 7 are Bitline7_0 and Bitline7_1. To further ensure matching of pixel columns on the layout, two column lines are set for all pixel columns. For example... Figure 4 In this invention, besides the two column lines in columns 3 and 7, the remaining pixel columns (columns 1, 2, and 4) also have two column lines. Therefore, in each pixel column of this invention, one of the two pixel units simultaneously receiving row selection control signals is read out through the first column line, and the other pixel unit is read out through the second column line. This invention saves frame rate by simultaneously inputting row selection signals to pixel blocks every other row in a pixel column, allowing two pixel blocks of the same color to read out signals simultaneously. For example, the focusing photosensitive pixel unit corresponding to row 2, column 3 is read out through the first column line, and the non-focusing photosensitive pixel unit corresponding to row 0, column 3 is read out through the second column line. The image sensor provided in this embodiment can use a set of row selection control lines to output row selection control signals. The timing sequence of the image sensor using a set of row selection control lines in normal operating mode is as follows... Figure 5 As shown, the timing sequence read out in the vertical merge readout mode is as follows: Figure 6 As shown.

[0072] In some embodiments of the present invention, a combination of horizontal and vertical merge readout can also be implemented on a pixel array capable of using phase detection autofocus. Figure 7 The diagram shown is a schematic representation of the image sensor layout structure in another embodiment of the present invention, as follows: Figure 7 As shown, since the colors of the focused photosensitive pixel units in the focused pixel column are inconsistent with those of the non-focused photosensitive pixel units in the row every other row, in order to better optimize and control the focused pixel column, the row selection control lines include a first set of row selection control lines and a second set of selection control lines; the pixel array includes focused pixel rows (where focused photosensitive pixel units are set) Figure 7 In row 2), the first set of row selection control lines rs is used to control the non-focus photosensitive pixel units in the focused pixel row 2 to read out pixel signals; the second set of row selection control lines rsp is used to control the focused photosensitive pixel units in the focused pixel row 2 to read out pixel signals.

[0073] 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.

[0074] In merge readout mode, the focus pixel row (row2) does not read out pixel signals. The four pixel units at row K, column M, row K, column M+2, row K+2, column M, and row K+2, column M+2 simultaneously receive row selection control signals. For example... Figure 7 The four pixel units in row 1, column 1, column 3, column 1, and column 3 of the above pixel array simultaneously receive row selection control signals to read pixel signals. Among these four pixel units, adjacent pixel units located in the same pixel row and separated by one pixel unit are read together through the same column line, while adjacent pixel units located in the same pixel column and separated by one pixel unit are read through different column lines. Here, K and M are both positive integers, that is, column 1 and column 3 of row 1 are read through the same column line, column 1 and column 3 of row 3 are read through the same column line, column 1 and column 1 of row 3 are read through different column lines, and column 3 and column 3 of row 1 are read through different column lines.

[0075] In this invention, the focusing photosensitive pixel unit in the focusing pixel column and the non-focusing photosensitive pixel unit spaced an odd number of rows apart from the focusing photosensitive pixel unit simultaneously receive row selection signals, but output pixel signals through different column lines. A device is set at the ADC to select the column lines through timing. In effect, it is equivalent to setting an equivalent switch. In subsequent image processing, the pixel unit with the readout channel closed is processed to have the same display as the pixel unit with the readout channel open.

[0076] In this invention, the row selection control lines of the Nth row and the (N-2)th row of pixels, which are configured to focus photosensitive pixel unit pairs, are symmetrically arranged, where N is a positive integer greater than or equal to 2. In an embodiment of this invention, as shown... Figure 7 As shown, the layout is better matched by symmetrically distributing the selection control lines (rs and rsp) in row 0 (Row0) and row 2 (Row2). Alternatively, the row selection control lines in row 2 (Row2) and row 4 (Row4) can be symmetrically set.

[0077] In a preferred embodiment, 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 controls the readout of pixel signals from pixel units located in the same column as the non-focusing photosensitive pixel units in the Nth pixel row, and the second set of row selection control lines controls the readout of pixel signals from pixel units located in the same column as the focusing photosensitive pixel units in the Nth pixel row. Although two sets of row selection control lines are provided on pixel rows without focusing photosensitive pixel units, in actual signal control, only one set of row selection control lines is used to select the selected pixel row for pixel signal readout, while the other set of row selection control lines remains unused.

[0078] Specifically, the first group of row selection control corresponds to one control signal, namely, the first control signal dd_rs is transmitted to the first group of row selection control lines rs corresponding to the 0th and 2nd row pixel rows. <0> and rs <2> The second control signal dd_rsp <0> Transmit to the second row selection control line rsp corresponding to the 0th pixel row <0> and the third control signal dd_rsp <2> Transmit to the second group of row selection control lines (rsp) corresponding to the second row of pixels. <2> .

[0079] Specifically, the first group of row selection control lines outputs the first control signal to the Nth pixel row and the (N-2)th pixel row, so as to control the off-focus photosensitive pixel units in the Nth pixel row and the (N-2)th pixel row to read out the pixel signal respectively;

[0080] 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 the pixel signals;

[0081] 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 unit in the Nth row of pixels to read out the pixel signal.

[0082] More specifically, such as Figure 7 As shown, 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 the focusing photosensitive pixel units in the 0th and 2nd 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 non-focusing photosensitive pixel unit (Row0, Column3) in the 0th pixel row that is located in the same column as the focusing photosensitive pixel unit in the 2nd 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 (Row2, Column3) in the second row of pixels to be read and reads the pixel signal.

[0083] As another preferred implementation, two sets of row selection control signals are set for all pixel rows. That is, for each row of pixel units, 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 separately control two different color blocks in the same pixel row according to the mode requirements.

[0084] Specifically, in normal operating mode, the signal readout process of the image sensor is as follows:

[0085] For the (N-2)th pixel row (off-focus 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 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. 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.

[0086] For the Nth pixel row (focus 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 focus pixel row to read out pixel signals, and the second set of row selection control lines is used to control the focus photosensitive pixel units in the focus pixel row to read out pixel signals. More specifically, in this embodiment of the invention, the focus 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 Row2 / column3 and the pixel units corresponding to Row2 / column7) to read out pixel signals.

[0087] 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.

[0088] In the lateral and longitudinal combined readout mode, the signal readout process of image sensing is as follows:

[0089] The focus pixel row does not read out pixel signals, and adjacent pixel units located in the same pixel row and separated by one pixel unit are read out through the same column line, while adjacent pixel units located in the same pixel column and separated by one pixel unit are read out through different column lines. That is, except for the focus pixel row (row2) which is not working, the four pixel units of other pixel rows (e.g., row1 / column1, row1 / column3, row3 / column3, row3 / column1) simultaneously receive row selection control signals, but the pixel unit corresponding to row1 / column1 and the pixel unit corresponding to row1 / column3 are read out by merging through the second column line (Bitline1_0), and the pixel unit corresponding to row3 / column3 and the pixel unit corresponding to row3 / column1 are read out by merging through the first column line (Bitline3_1).

[0090] Its timing control during horizontal and vertical merging readout control is as follows: Figure 8 and Figure 9 As shown, it needs to be explained that... Figure 8 and Figure 9 The dashed line indicates that the corresponding signal can be either low or high level under this timing condition, and both can achieve the technical solution of this case. Because the color blocks of the focusing pixel PDAF and the pixel units to be merged differ in horizontal binning, it is necessary to prevent the second row (Row2) from effectively merging and reading out binning. Therefore, all signals in the second row (Row2) must be turned off. In merge readout mode, all signals in the second row (Row2) must be turned off. Two sets of row selection control lines are used to control the focusing and non-focusing photosensitive pixel units respectively, so that when the pixel array is horizontally merged and read out, the focusing pixel row cannot be opened. Correspondingly, adjacent pixel units in other pixel rows separated by one pixel unit are merged and read out through the same column line, while adjacent pixel units in the same pixel column separated by one pixel unit are read out through different column lines. The resulting pixel value data of the pixel unit becomes 1 / 4 of the original, so the processing time for all data also becomes 1 / 4 of the original. This greatly improves the frame rate of image processing, allowing for the capture of more slow-motion scenes.

[0091] 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 focus PDAF, but phase information can still be obtained. When reading out binning laterally, 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.

[0092] Example 2:

[0093] The present invention also provides a signal readout control method for an image sensor, the method comprising at least the following steps:

[0094] Control the pixel array to enter focus mode;

[0095] Receive control signals and control the pixel units of the row to be read to read out pixel signals according to the control signals;

[0096] The row selection control line is used to control the first area of ​​a focusing photosensitive pixel unit in the focusing pixel column to read out the pixel signal and output the first output value through the first column line;

[0097] The row selection control line is used to control the second region of another focusing photosensitive pixel unit in the focusing pixel column to read out the pixel signal and output the second output value through the first column line; the second region and the first region form a complementary region of the focusing photosensitive pixel unit;

[0098] Focusing control is performed based on the first and second output values.

[0099] In this embodiment, since the image sensor has been described in detail in Embodiment 1, it will not be described again in this embodiment.

[0100] In the focus mode, the image sensor readout control method of the present invention controls the focus photosensitive pixel units in the pixel focus column by receiving row selection control signals simultaneously, and performs focus control by outputting a first output value and a second output value respectively.

[0101] In a preferred embodiment of the present invention, focusing control based on the first output value and the second output value includes:

[0102] Generate a first phase value based on the first output value;

[0103] A second phase value is generated based on the second output value;

[0104] Focusing control is performed based on the first phase value and the second phase value.

[0105] 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.

[0106] As a further limitation of this embodiment of the invention, the method also includes:

[0107] The control pixel array enters the normal working mode, and the row selection control line outputs row selection control signals to each pixel row in sequence, so that the pixel rows in the pixel array are read out one by one;

[0108] The control pixel array enters a merge readout mode, where every two rows of pixels spaced an odd number of rows simultaneously receive row selection control signals. In a pixel column containing a focusing photosensitive pixel unit, the control enables the focusing photosensitive pixel unit through the channel readout from the first column line, and disables the non-focusing photosensitive pixel units spaced an odd number of rows away from the focusing photosensitive pixel unit through the channel readout from the second column line; or, the focusing photosensitive pixel unit disables the channel readout from the first column line, and disables the non-focusing photosensitive pixel units spaced an odd number of rows away from the focusing photosensitive pixel unit through the channel readout from the second column line.

[0109] In this embodiment of the invention, readout via two column lines allows for effective readout regardless of whether the focusing photosensitive pixel unit is turned off during vertical readout.

[0110] Considering the presence of focusing photosensitive pixel units, when performing horizontal readout control or horizontal / vertical readout control, two sets of row selection control lines are set. 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 non-focusing photosensitive pixel units in the Nth pixel row to read out 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 pixel signals.

[0111] As a preferred embodiment of the present invention, in the merge readout mode, the readout channel of the pixel signal of the focused pixel row is closed, and the four pixel units in the Kth row and Mth column, the Kth row and M+2th column, the K+2th row and M+2th column, and the K+2th row and M+2th column simultaneously receive the row selection control signal. Among the four pixel units, adjacent pixel units located in the same pixel row and separated by one pixel unit are merged and read out through the same column line, and adjacent pixel units located in the same pixel column and separated by one pixel unit are read out through the first column line and the second column line, respectively.

[0112] When entering the merge readout mode, this invention addresses the issue that the color blocks of the focused pixel's PDAF and the pixel units to be merged differ. Therefore, the readout channel of the focused pixel row is closed. Adjacent pixel units in the same row, separated by one pixel unit, are merged and read out through the same column line. Adjacent pixel units in the same column, separated by one pixel unit, are read out through different column lines. During the initial merge readout through the same column, one column line is output while the other is idle. This results in column-wise data merging and halving of data volume, improving the frame rate. Furthermore, during vertical merging, the data volume is also halved, further enhancing the frame rate. The overall effect is that the amount of data output at any given moment is the same as before merge readout, but the total data volume is reduced to 1 / 4 of its original value. Consequently, the processing time for all data is also reduced to 1 / 4 of its original value. This significantly improves the frame rate of image processing, enabling the capture of more slow-motion scenes.

[0113] In summary, the image sensor of this invention, through an optimized pixel array layout, controls the selection of pixel units in the row to be read by simultaneously receiving control signals, enabling them to read pixel signals concurrently. The pixel unit layout in the pixel array of this invention achieves a larger pixel range and photosensitive area, and since the four pixels in each pixel unit use the same control signal, pixel processing speed can be greatly improved. Furthermore, the use of a Bayer array arrangement significantly enhances phase detection autofocus performance. Additionally, the vertical merging readout technology further improves the frame rate of pixel processing. Therefore, this invention effectively overcomes the various shortcomings of existing technologies and possesses high industrial applicability.

[0114] 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 including pixels of the same color arranged in a 2×2 structure; wherein, the pixel array includes a focusing pixel column, in which some blue or red pixels are replaced with green pixels to form a focusing photosensitive pixel unit, and the focusing photosensitive pixel unit is partially obscured to obtain its output value, and focusing control is performed based on the output value; The row selection control line receives the row selection control signal and controls the selection of pixel units in the row to be read out according to the row selection control signal; every two focus-sensing pixel units located in the same pixel row form a focus-sensing pixel unit pair. Column lines are used to read the pixel signals of the pixel units in the row to be read. The column lines include a first column line and a second column line. In the focusing pixel column, the focusing photosensitive pixel unit is read through the first column line, and the non-focusing photosensitive pixel unit that is spaced an odd number of rows away from the focusing photosensitive pixel unit is read through the second column line. This is used to independently control the focusing photosensitive unit and the non-focusing photosensitive pixel unit that is spaced an odd number of rows away from the focusing photosensitive pixel unit in the focusing pixel column. The image sensor includes a normal operating mode and a merged readout mode; in the normal operating mode, the pixel rows in the pixel array are read out row by row; in the merged readout mode, at least two pixel rows with an odd number of rows between them simultaneously receive row selection control signals, and in the focusing pixel column, the focusing photosensitive pixel unit that simultaneously receives the row selection control signal and the non-focusing photosensitive pixel unit with an odd number of rows between them each correspond to a readout channel, with one readout channel open and the other readout channel closed.

2. The image sensor according to claim 1, characterized in that, Two focusing photosensitive pixel units located in the same pixel row form a focusing photosensitive pixel unit pair, and the occluded areas of the focusing photosensitive pixel units in each focusing photosensitive pixel unit pair are complementary, so as to obtain the output value of each focusing photosensitive pixel unit in the focusing photosensitive pixel unit pair respectively, and perform focusing control based on the output value.

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

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

5. The image sensor according to claim 1, characterized in that, In each pixel column, one of the two pixel units that simultaneously receive the row selection control signal is read out through the first column line, and the other pixel unit is read out through the second column line.

6. The image sensor according to claim 1, characterized in that, The row selection control lines include a first group of row selection control lines and a second group of selection control lines; The pixel array includes a focus pixel row in which the focus photosensitive pixel unit is disposed; 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 in the focus pixel row to read out the pixel signal. 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. In the merge readout mode, the focus pixel row does not read out pixel signals. The four pixel units in the Kth row and Mth column, the Kth row and M+2th column, the K+2th row and Mth column, and the K+2th row and M+2th column simultaneously receive row selection control signals. Among these four pixel units, adjacent pixel units located in the same pixel row and separated by one pixel unit are merged and read out through the same column line, while adjacent pixel units located in the same pixel column and separated by one pixel unit are read out through different column lines. K and M are both positive integers.

7. The image sensor according to claim 6, 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 units, are symmetrically arranged, where N is a positive integer greater than or equal to 2.

8. The image sensor according to claim 7, 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.

9. The image sensor according to claim 8, 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, so as to control the off-focus photosensitive pixel units in the Nth pixel row and the (N-2)th pixel row to read out the pixel signal respectively; 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.

10. A signal readout control method for an image sensor, characterized in that, Including the image sensor of claim 1, the method includes at least the following steps: Control the pixel array to enter focus mode; Receive control signals and control the pixel units of the row to be read to read out pixel signals according to the control signals; The row selection control line is used to control the first region of a focusing photosensitive pixel unit in the focusing pixel column to read out the pixel signal and output the first output value through the first column line; The row selection control line is used to control the second region of another focusing photosensitive pixel unit in the focusing pixel column to read out the pixel signal and output the second output value through the first column line; the second region and the first region form a complementary region of the focusing photosensitive pixel unit; Focusing control is performed based on the first output value and the second output value.

11. The signal readout control method for an image sensor according to claim 10, 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.

12. The signal readout control method for an image sensor according to claim 10, characterized in that, The method further includes: The pixel array is controlled to enter a normal working mode, and the row selection control line sequentially outputs row selection control signals to each pixel row so that the pixel rows in the pixel array are read out one by one; The pixel array is controlled to enter a merge readout mode, where every two rows of pixels spaced an odd number of rows simultaneously receive row selection control signals; in a pixel column containing a focusing photosensitive pixel unit, the focusing photosensitive pixel unit is controlled to open through the channel readout from the first column line, while the non-focusing photosensitive pixel units spaced an odd number of rows away from the focusing photosensitive pixel unit are controlled to close through the channel readout from the second column line; or... In a pixel column with a focusing photosensitive pixel unit, the focusing photosensitive pixel unit is turned off through the channel read out from the first column line, and the non-focusing photosensitive pixel unit, which is spaced an odd number of rows away from the focusing photosensitive pixel unit, is turned on through the channel read out from the second column line.

13. The signal readout control method for an image sensor according to claim 10, 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; two sets of row selection control lines are set, wherein the first set of row selection control lines is used to control the pixel unit in the (N-2)th pixel row that is located in the same column as the non-focusing photosensitive pixel unit in the Nth pixel row to read out the pixel signal; the second set of row selection control lines is used to control the pixel unit in the (N-2)th pixel row that is located in the same column as the focusing photosensitive pixel unit in the Nth pixel row to read out the pixel signal.

14. The signal readout control method for an image sensor according to claim 13, characterized in that, The pixel array includes a focusing pixel row where the focusing photosensitive pixel unit is disposed; in the merge readout mode, the readout channel of the pixel signal of the focusing pixel row is closed, and four pixel units in the Kth row M column, Kth row M+2 column, K+2 row M column and K+2 row M+2 column simultaneously receive row selection control signals. Among the four pixel units, adjacent pixel units located in the same pixel row and separated by one pixel unit are merged and read out through the same column line, and adjacent pixel units located in the same pixel column and separated by one pixel unit are read out through the first column line and the second column line respectively.

Images