CN116744107A - Image sensor and reading control method thereof - Google Patents

Abstract

The invention provides an image sensor and a reading control method thereof, wherein 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 pixel units in the pixel array are arranged as focusing photosensitive pixel unit pairs, and focusing control is carried out based on output values of the focusing photosensitive pixel units in the focusing photosensitive pixel unit pairs; the row selection control line receives and controls and selects pixel units of a row to be read according to the control signal to read out pixel signals; the row selection control lines comprise a first group of row selection control lines and a second group of row selection control lines; the pixel array comprises focusing pixel rows, wherein a first group of row selection control lines are used for controlling non-focusing photosensitive pixel units in the focusing pixel rows to read out pixel signals, and a second group of row selection control lines are used for controlling the focusing photosensitive pixel units in the focusing pixel rows to read out pixel signals. The invention improves the phase focusing performance and also improves the frame rate of pixel processing.

Description

Image sensor and reading control method thereof

Technical Field

The present invention relates to image signal control technology, and more particularly, to an image sensor and a reading control method thereof.

Background

Image sensors are commonly used in various electronic devices and products, such as digital cameras, video monitoring devices, face recognition, unmanned aerial vehicles, and the like, to capture and recognize images.

In the prior art, various optimization schemes are required to enhance the phase focusing technique, and the pixel array of the bayer array is shown in fig. 1, where G represents Green, R represents Red, and B represents Blue in the three primary colors. Two G's are used in a 2x2 pixel array because they are the most sensitive to green by the human eye.

For the bayer array shown in fig. 1, the circuit diagram of the bayer array is shown in fig. 2, the 4 photodiodes correspond to filters of three colors, signals of which the photodiodes are controlled by tx series transmission tubes are transmitted to the node FD, the signals are reset by the reset transistor rst, and finally, the pixel selection transistor rs is controlled by the control signal rowsel to perform row selection operation, so that pixel information is output.

However, the conventional bayer array is inserted with a phase focusing technology, so that the phase focusing performance is relatively poor, and therefore, a solution to the technical defect is needed.

Disclosure of Invention

In view of the above-mentioned drawbacks of the prior art, an object of the present invention is to provide an image sensor and a reading control method thereof for solving the problem of poor relative focusing performance in the prior art.

To achieve the above and other related objects, the present invention provides an image sensor comprising:

a pixel array including a plurality of pixel units arranged in a bayer array, each of the pixel units including pixel points laid out in a 2×2 structure and having the same color; a part of pixel units in the pixel array are arranged as focusing photosensitive pixel unit pairs, wherein the focusing photosensitive pixel unit pairs comprise two focusing photosensitive pixel units, each focusing photosensitive pixel unit is at least partially shielded, shielded areas of the focusing photosensitive pixel units in each focusing photosensitive pixel unit pair are complementary, so that output values of the focusing photosensitive pixel units in the focusing photosensitive pixel unit pairs are respectively obtained, and focusing control is performed based on the output values;

a row selection control line for receiving a control signal and controlling and selecting pixel units of a row to be read to read out pixel signals according to the control signal; the row selection control lines comprise a first group of row selection control lines and a second group of row selection control lines;

the pixel array comprises focusing pixel rows provided with the focusing photosensitive pixel unit pairs, the first group of row selection control lines are used for controlling non-focusing photosensitive pixel units in the focusing pixel rows to read out pixel signals, and the second group of row selection control lines are used for controlling the focusing photosensitive pixel units in the focusing pixel rows to read out pixel signals.

Preferably, the focusing photosensitive pixel units in the focusing photosensitive pixel unit pair are spaced by odd rows.

Preferably, the pair of focus sensitive pixel units is formed as green pixels replacing either blue or red pixels in the bayer array.

Preferably, the pair of focus sensitive pixel cells occupy 3% of the pixel array.

Preferably, the N-th row of pixel lines and the N-2-th row of pixel lines of the pair of focusing photosensitive pixel units are symmetrically arranged, wherein N is a positive integer greater than or equal to 2.

Preferably, the N-2 th row of pixels is correspondingly provided with the first group of row selection control lines and the second group of row selection control lines;

in the N-2 th row of pixel rows, the first group of row selection control lines are used for controlling pixel signals to be read out from pixel units which are positioned in the same column as the non-focal sensitive pixel units in the N-th row of pixel rows, and the second group of row selection control lines are used for controlling pixel signals to be read out from pixel units which are positioned in the same column as the focal sensitive pixel units in the N-th row of pixel rows.

Preferably, the first group of row selection control lines outputs a first control signal to the nth row of pixels and the N-2 th row of pixels to control the unfocused photosensitive pixel units in the nth row of pixels and the N-2 th row of pixels to read out pixel signals; the second group of row selection control lines output a second control signal to the N-2 row of pixel rows to control pixel units in the N-2 row of pixel rows and the pixel units in the same column with the focusing photosensitive pixel units in the N row of pixel rows to read out pixel signals; the second group of row selection control lines output a third control signal to the nth row of pixel rows to control the focusing photosensitive pixel units in the nth row of pixel rows to read out pixel signals.

Preferably, the image sensor includes a normal operation mode and a combined readout mode;

in the normal working mode, the first group of row selection control lines are used for controlling the non-focusing photosensitive pixel units to read out pixel signals, and the second group of row selection control lines are used for controlling the focusing photosensitive pixel units to read out pixel signals;

in the combined readout mode, the focusing pixel row does not perform readout of the pixel signals, and the pixel signals of adjacent same-color pixel units which are positioned in the same pixel row and are separated by one pixel unit are output through the same column transmission control line.

To achieve the above and other related objects, the present invention also provides a method for controlling reading of an image sensor, which is applicable to the above image sensor, and the method includes the following steps:

controlling the pixel array to enter a focusing mode;

receiving an output control signal of the digital control circuit to control and select pixel units of a row to be read to read out pixel signals; the row selection control lines comprise a first group of row selection control lines and a second group of row selection control lines;

the line selection control line controls a focusing pixel line provided with the focusing photosensitive pixel unit to obtain an output value of the focusing photosensitive pixel unit to the pixel unit in the pair; wherein, the first area of one focusing photosensitive pixel unit in the focusing pixel row is controlled to read out the pixel signal and serve as a first output value; controlling a second area of another focusing photosensitive pixel unit in the focusing pixel row to read out pixel signals and serve as a second output value; the first region and the second region are complementary regions;

and performing focusing control according to the first output value and the second output value.

Preferably, the performing focus control according to the first output value and the second output value includes:

generating a first phase value from the first output value;

generating a second phase value from the second output value;

and performing focusing control according to the first phase value and the second phase value.

Preferably, the method further comprises:

the first group of row selection control lines are used for controlling pixel units in the N-2 th row of pixel rows and the pixel units in the same column with the non-focusing photosensitive pixel units in the N-th row of pixel rows to read out pixel signals;

the second group of row selection control lines are used for controlling pixel units in the N-2 th row of pixel rows and the pixel units in the same column with the focusing photosensitive pixel units in the N-th row of pixel rows to read out pixel signals.

Preferably, the method further comprises:

controlling the pixel array to enter a merging read-out mode;

and the readout channels of the pixel signals of the focusing pixel rows are controlled to be closed, and the pixel signals of the adjacent same-color pixel units which are positioned in the same pixel row and are separated by one pixel unit are output through the same column transmission control line, wherein the same column output control line is one column in which the adjacent same-color pixel units are positioned.

As described above, the image sensor and the reading control method thereof of the present invention have the following advantages:

the image sensor of the invention realizes the control and selection of the pixel units of the row to be read to read out the pixel signals by optimizing the pixel array of the layout and adopting two groups of row selection control lines; the pixel unit layout in the pixel array can realize a larger pixel range and a photosensitive area, and four pixel points included in the pixel unit sample the same control signal, so that the pixel processing speed can be greatly improved. Meanwhile, the Bayer array arrangement mode is adopted, so that the phase focusing performance can be greatly improved. In addition, the frame rate of pixel processing can be further improved by adopting a transverse merging read-out binding technology.

Drawings

Fig. 1 shows a schematic layout of a bayer array of the prior art.

Fig. 2 shows a schematic circuit configuration of a bayer array according to the prior art.

Fig. 3 is a schematic layout diagram of a pixel unit in the pixel array according to the present invention.

Fig. 4 is a schematic layout diagram of an image sensor according to an embodiment of the invention.

Fig. 5 is a schematic layout diagram of an image sensor according to another embodiment of the invention.

Fig. 6 is a timing chart of the image sensor shown in fig. 5 in a normal operation mode.

Fig. 7 is a timing chart showing the image sensor in the merged read mode shown in fig. 5.

Detailed Description

Other advantages and effects of the present invention will become apparent to those skilled in the art from the following disclosure, which describes the embodiments of the present invention with reference to specific examples. The invention may be practiced or carried out in other embodiments that depart from the specific details, and the details of the present description may be modified or varied from the spirit and scope of the present invention.

Please refer to fig. 3-7. It should be noted that, the illustrations provided in the present embodiment merely illustrate the basic concept of the present invention by way of illustration, and only the components related to the present invention are shown in the drawings and are not drawn according to the number, shape and size of the components in actual implementation, and the form, number and proportion of the components in actual implementation may be arbitrarily changed, and the layout of the components may be more complex.

The invention samples two control signals to control the pixel units respectively through the time sequence, realizes the control functions of combining and reading out the binding and the phase focusing transversely, improves the frame rate, and simultaneously improves the phase focusing (Phase detection auto-focus, PDAF) performance and the dynamic range.

Based on the technical conception, the invention provides a technical scheme of an image sensor and a reading control method thereof to solve the problems in the prior art, and the technical conception and the technical scheme of the invention are described in detail through the following embodiments.

Embodiment one:

fig. 4 is a schematic layout structure of an image sensor according to an embodiment of the invention. The embodiment of the present invention will be described in detail with reference to fig. 4.

The image sensor includes a pixel array and a row selection control line;

the pixel array includes a plurality of pixel units arranged in a bayer array, each pixel unit including pixel dots laid out in a 2×2 structure and having the same color; a part of pixel units in the pixel array are arranged as focusing photosensitive pixel unit pairs, wherein the focusing photosensitive pixel unit pairs comprise two focusing photosensitive pixel units, each focusing photosensitive pixel unit is at least partially shielded, the shielded areas of the two focusing photosensitive pixel units in each focusing photosensitive pixel unit pair are complementary, so that output values of the focusing photosensitive pixel units in the focusing photosensitive pixel unit pairs are respectively obtained, and focusing control is carried out based on the output values;

the row selection control line receives a control signal to control and select pixel units of a row to be read to read out pixel signals; the row selection control lines comprise a first group of row selection control lines and a second group of row selection control lines;

the pixel array comprises focusing pixel rows provided with focusing photosensitive pixel unit pairs, a first group of row selection control lines are used for controlling non-focusing photosensitive pixel units in the focusing pixel rows to read out pixel signals, and a second group of row selection control lines are used for controlling the focusing photosensitive pixel unit pairs in the focusing pixel rows to read out pixel signals.

Specifically, the pixel array of the present invention includes 8×8 pixel units arranged in bayer array, each pixel unit is a pixel dot having the same color and being laid out in a 2×2 structure, as shown in fig. 3, and is respectively Green (Green, G), red (Red, R) and Blue (Blue, B). The whole array of the pixel array is highly symmetrical, and the tubes in the pixel units are all NMOS tubes, so that the transmission speed is high, and high-level enabling is required in the control process.

Specifically, the focusing photosensitive pixel units in the focusing photosensitive pixel unit pair are separated by odd rows. In the embodiment of the present invention, the pixel unit corresponding to the 2 nd Row and the 3 rd Column (Row 2, column 3) and the pixel unit corresponding to the 2 nd Row and the 7 th Column (Row 2, column 7) in the pixel array are set as the focusing pixel photosensitive pixel unit pair. In the phase focusing process, two focusing photosensitive pixel units are respectively blocked, for example, in fig. 4, the left half of a first focusing photosensitive pixel unit corresponding to the 2 nd Row and the 3 rd Column (Row 2, column 3) is blocked, the right half of a second focusing photosensitive pixel unit corresponding to the 2 nd Row and the 7 th Column (Row 2, column 7) is blocked, and the left half blocking area of the first focusing photosensitive pixel unit and the right half blocking area of the second focusing photosensitive pixel unit are complemented, so that output values of the focusing photosensitive units, namely, a first output value output by the first focusing photosensitive pixel unit and a second output value output by the second focusing photosensitive pixel unit, are obtained, and focusing control is performed through a first phase value generated by the first output value and a second phase value generated by the second output value. That is, the right half imaging of the pair of focusing photosensitive pixel units is realized through the first output value and the left half imaging of the pair of focusing photosensitive pixel units is realized through the second output value, the phase difference is generated based on the first phase value and the second phase value, and then the phase shift is performed to realize one-step rapid focusing.

In the embodiment of the present invention, the left half side of one focusing photosensitive pixel unit and the right half side of the other focusing photosensitive pixel unit are complementary to each other in the blocked area, and as other embodiments, the upper half side of one focusing photosensitive pixel unit and the lower half side of the other focusing photosensitive pixel unit in the pair of focusing photosensitive pixel units may also be used; or one quarter of one focus sensitive pixel unit and three quarters of the other focus sensitive pixel unit.

The image sensor realizes the control and selection of pixel units of a row to be read to read out pixel signals by optimizing a pixel array of the layout and adopting two groups of row selection control lines; the pixel unit layout in the pixel array can realize a larger pixel range and a photosensitive area, and four pixel points included in the pixel unit sample the same control signal, so that the pixel processing speed can be greatly improved. Meanwhile, the performance of phase focusing can be greatly improved by adopting the arrangement mode of the Bayer array.

In the layout setting of the pixel array, the invention considers that the green photosensitivity is good, so that the focusing photosensitive pixel units are formed for replacing blue pixels or red pixels in the Bayer array by green pixels, so that the pixel array has more photosensitive units of the green pixels, and the photosensitivity of the pixel array is further improved.

Because of the existence of the focusing photosensitive pixel units, the color block settings of the pixel Row corresponding to the nth Row and the pixel Row of the N-2 Row are different, for example, as shown in fig. 4, the color block settings of the pixel Row of the 2 nd Row (Row 2) and the pixel Row of the 0 th Row (Row 0) are different, and because parasitic capacitance exists on the signal line, the surrounding environment of each pixel unit needs to be kept consistent, so that in order to perform better optimal control when the pixel array is read out, two groups of Row selection control signals are set for the pixel Row corresponding to the nth Row and the pixel Row of the N-2 Row, and in order to further enable each pixel Row to be matched on the layout, as shown in fig. 5, two groups of Row selection control signals are set for all the pixel rows.

The first group of row selection control corresponds to a control signal, specifically, a first control signal dd_rs is transmitted to a first group of row selection control lines rs <0:7> corresponding to each pixel row, and a second control signal dd_rsp <0> and a third control signal dd_rsp <1> are respectively transmitted to a second group of row selection control lines rsp <0:7> corresponding to each pixel row.

Specifically, a first group of row selection control lines rs receives a first control signal dd_rs, and sequentially controls and selects an N row pixel row to be read and a non-focusing photosensitive pixel unit in an N-2 row pixel row to read according to the first control signal dd_rs so as to read pixel signals; the second group of row selection control lines rsp receive a second control signal dd_rsp <0>, and control and select pixel units which are positioned in the same column as the focusing photosensitive pixel units in the N row of pixel rows in the N-2 row of pixel rows to be read according to the second control signal dd_rsp <0> to read pixel signals; the second group of row selection control lines rsp receives the third control signal dd_rsp <1>, and controls and selects the focusing photosensitive pixel units in the N row of pixels to be read to read out pixel signals according to the third control signal dd_rsp <1 >.

In the invention, the N-th row of pixel lines and the N-2-th row of pixel lines of the focusing photosensitive pixel unit pair are symmetrically arranged, wherein N is a positive integer greater than or equal to 2. In the embodiment of the invention, the layout is more matched by the symmetrical distribution of the Row0 (Row 0) and the Row2 (Row 2) selection control lines (rs and rsp). As another embodiment, the Row selection control lines for selecting the 2 nd Row (Row 2) pixel Row and the 4 th Row (Row 4) pixel Row may be symmetrically arranged.

The image sensor comprises a normal working mode and a combined reading mode;

in the normal working mode, the first group of row selection control lines rs are used for controlling the non-focusing photosensitive pixel units to read out pixel signals, and the second group of row selection control lines rsp are used for controlling the focusing photosensitive pixel units to read out pixel signals;

in the combined readout mode, the pixel signals of the adjacent same-color pixel units which are positioned in the same pixel row and are separated by one pixel unit are output through the same column transmission control line bit.

The invention controls pixel unit readout of each row of pixel rows row by row through a first group of row selection control lines rs <0:7> and a second group of row selection control lines rsp <0:7> based on a first control signal, a second control signal and a third control signal. In the embodiment of the invention, because of the existence of the focusing photosensitive pixel units, the color blocks of the focusing pixel row corresponding to the N line and the N-2 line pixel row are set differently to meet layout matching, so that control is performed by two groups of different row selection control signals, and for other pixel rows, although two groups of control signals are adopted for layout matching, the first control signal signals of the row are the same as all pixel units controlling the pixel row, so that one rs control signal or rsp control signal can be directly adopted.

More specifically, in the normal operation mode, the pixel row readout process of each row is respectively:

for row N-2 pixels: the N-2 row of pixel rows is correspondingly provided with a first group of row selection control lines and a second group of row selection control lines; in the N-2 row pixel row, the first group of row selection control lines are used for controlling pixel units in the same column as the non-focus photosensitive pixel units in the N row pixel row to read out pixel signals, and the second group of row selection control lines are used for controlling pixel units in the same column as the focus photosensitive pixel units in the N row pixel row to read out pixel signals. More specifically, in the embodiment of the present invention, in the 0 th Row of pixels (Row 0), rs <0> in the first group of Row selection control lines controls the non-focusing photosensitive pixel units (pixel units corresponding to column1, column2, column4, column5, column6, column 8) to read out pixel signals based on the first control signal dd_rs, and rsp <0> in the second group of Row selection control lines controls the focusing photosensitive pixel units (pixel units corresponding to Row0/column3 and pixel units corresponding to Row0/column 7) to read out pixel signals based on the second control signal dd_rsp <0 >.

For the nth row of pixels: the N-th row of pixel rows is correspondingly provided with a first group of row selection control lines and a second group of row selection control lines; the first group of row selection control lines are used for controlling the non-focusing photosensitive pixel units in the focusing pixel rows to read out pixel signals, and the second group of row selection control lines are used for controlling the focusing photosensitive pixel units in the focusing pixel rows to read out pixel signals. More specifically, in the embodiment of the present invention, the focusing pixel Row2 (Row 2), based on the first control signal, the first group of Row selection control lines rs <2> control the non-focusing photosensitive pixel units (pixel units corresponding to column1, column2, column4, column5, column6, column 8) to read out pixel signals, and the second group of Row selection control lines rsp <2> control the focusing photosensitive pixel units (pixel units corresponding to column3 and pixel units corresponding to column 7) to read out pixel signals.

For other rows (N-1 row, n+1 row, etc.) of pixels: and controlling all pixel units in the corresponding pixel row to read out pixel signals through the first group of row selection control lines or the second group of row selection control lines. More specifically, in the embodiment of the present invention, the 1 st Row of pixel rows (Row 1), based on the first control signal, the first group of Row selection control lines rs <1> control all the pixel units (pixel units corresponding to column1-column 8) to read out the pixel signals.

More specifically, in the combined readout mode, the readout of the pixel signals is not performed for the focusing pixel row, and the pixel signals of the adjacent same-color pixel units located in the same pixel row and separated by one pixel unit are output through the same column transmission control line; namely, columns 1/column3, column2/column4, column5/column7 and column6/column8 of other pixel rows except for the non-working focusing pixels can be laterally binned in the same corresponding row, and a signal is adopted for control and output; for example, when Row0 (Row 0) is read, pixel values of color blocks of column6/column8 are combined and read out of the bin, and then data after the bin is combined and read out of the bin can be gated and output from column6 or column8 through an analog-to-digital converter (AD 6 or AD 8), and an idle analog-to-digital converter AD is left idle, so that pixels are sparse, data are halved, and frame rate improvement is realized in the column-direction data reading process.

The timing control in the specific normal working mode and the combined readout mode are shown in fig. 6 and fig. 7, respectively, and it is to be noted that the dashed line in fig. 6 represents that the corresponding signal in the timing may be low level or high level, and the technical scheme of the scheme may be implemented. Since the lateral merge readout has a focus pixel PDAF different from the color block of the pixel unit to be merged, the Row2 (Row 2) needs to be controlled so that the lateral effective merge readout cannot be performed, and thus, as shown in fig. 7, the signals of the Row2 (Row 2) need to be all turned off in the merge readout mode. The two groups of row selection control lines are used for respectively controlling the focusing photosensitive pixel units and the non-focusing photosensitive pixel units, so that the focusing pixel rows cannot be opened when the pixel array is read out in a horizontal merging mode, and correspondingly, other pixel rows can be read out in a merging mode through the same column line, and the obtained pixel value data of the pixel units are halved, so that the frame rate is improved.

In the invention, the focusing photosensitive pixel unit pair occupies 3% of the pixel array, and pixels are not greatly reduced, namely, the pixel units corresponding to the phase focusing PDAF are fewer when image information is read out normally, but phase information can be obtained; when the horizontal merging is read out, the phase information cannot be obtained, and one row of pixel units are fewer when the image information is obtained, but the frame rate can be greatly improved.

Embodiment two:

a reading control method of an image sensor, which is applicable to the image sensor described in the first embodiment, the method comprising the steps of:

controlling the pixel array to enter a focusing mode;

receiving an output control signal of the digital control circuit to control and select pixel units of a row to be read to read out pixel signals;

the line selection control line controls a focusing pixel line provided with the focusing photosensitive pixel unit to obtain an output value of the focusing photosensitive pixel unit to the pixel unit in the pair; wherein, the first area of one focusing photosensitive pixel unit in the focusing pixel row is controlled to read out the pixel signal and serve as a first output value; controlling a second area of another focusing photosensitive pixel unit in the focusing pixel row to read out pixel signals and serve as a second output value; the first region and the second region are complementary regions;

and performing focusing control according to the first output value and the second output value.

In this embodiment, since the image sensor is described in detail in the first embodiment, detailed description is omitted in this embodiment.

In the reading control method of the image sensor, when in a focusing mode, two groups of row selection control lines are used for respectively controlling focusing pixel rows, and focusing control is respectively carried out through the output first output value and the output second output value. The focusing pixel rows including the focusing photosensitive pixel units can be individually controlled by two sets of row selection control lines.

As a preferred embodiment of the present invention, performing focus control based on the first output value and the second output value includes:

generating a first phase value from the first output value;

generating a second phase value from the second output value;

and performing focusing control according to the first phase value and the second phase value.

After the first output value and the second output value are obtained, a first phase value and a second phase value can be calculated and generated, phase difference information of the first phase value and the second phase value can be converted into focusing distance information, and phase focusing is achieved by adjusting the position of the lens according to focusing distance information, so that phase focusing detection is simpler to achieve.

As a further definition of an embodiment of the invention, the method further comprises:

the first group of row selection control lines are used for controlling pixel units in the same column as the non-focusing photosensitive pixel units in the N-2 row pixel rows to read out pixel signals;

the second group of row selection control lines are used for controlling pixel units in the same column as the focusing photosensitive pixel units in the N-2 row pixel rows to read out pixel signals.

In the embodiment of the invention, in the process of reading control, for both focusing pixel rows and non-focusing pixel rows for layout matching, pixel signals are read out from non-focusing pixel columns through a first group of row selection control lines, and pixel signals are read out from focusing pixel columns through a second group of row selection control lines.

As a preferred implementation of the embodiment of the present invention, the method further comprises:

controlling the pixel array to enter a merging read-out mode;

and the readout channels for controlling pixel signals of the focusing pixel rows are closed, and pixel signals of adjacent pixel units with the same color, which are positioned in the same pixel row and are separated by one pixel unit, are output through the same column transmission control line, wherein the same column transmission control line is one column where the adjacent pixel units with the same color are positioned.

When the invention enters the merging read-out mode, because the color blocks of the focusing pixel PDAF and the pixel units needing to be merged are different, the read-out channel of the pixel signals of the focusing pixel row is required to be controlled to be closed, the pixel signals of the adjacent pixel units with the same color of the pixel units at intervals of the same row of the non-focusing pixel row are output through one column line, and the other column line is idle, so that the number of columns is merged, the data is halved, and the frame rate is improved in the data read-out process of the column direction.

In summary, the invention realizes the control of selecting the pixel units of the row to be read to read out the pixel signals by optimizing the pixel array of the layout and sampling two groups of row selection control lines; the pixel unit layout in the pixel array can realize a larger pixel range and a photosensitive area, and four pixel points included in the pixel unit sample the same control signal, so that the pixel processing speed can be greatly improved. Meanwhile, the Bayer array arrangement mode is adopted, so that the phase focusing performance can be greatly improved. In addition, the frame rate of pixel processing can be further improved by adopting a transverse merging read-out technology. Therefore, the invention effectively overcomes various defects in the prior art and has high industrial utilization value.

The above embodiments are merely illustrative of the principles of the present invention and its effectiveness, and are not intended to limit the invention. Modifications and variations may be made to the above-described embodiments by those skilled in the art without departing from the spirit and scope of the invention. Accordingly, it is intended that all equivalent modifications and variations of the invention be covered by the claims, which are within the ordinary skill of the art, be within the spirit and scope of the present disclosure.

Claims (12)

1. An image sensor, the image sensor comprising:

a pixel array including a plurality of pixel units arranged in a bayer array, each of the pixel units including pixel points laid out in a 2×2 structure and having the same color; a part of pixel units in the pixel array are arranged as focusing photosensitive pixel unit pairs, wherein the focusing photosensitive pixel unit pairs comprise two focusing photosensitive pixel units, each focusing photosensitive pixel unit is at least partially shielded, shielded areas of the focusing photosensitive pixel units in each focusing photosensitive pixel unit pair are complementary, so that output values of the focusing photosensitive pixel units in the focusing photosensitive pixel unit pairs are respectively obtained, and focusing control is performed based on the output values;

a row selection control line for receiving a control signal and controlling and selecting pixel units of a row to be read to read out pixel signals according to the control signal; the row selection control lines comprise a first group of row selection control lines and a second group of row selection control lines;

the pixel array comprises focusing pixel rows provided with the focusing photosensitive pixel unit pairs, the first group of row selection control lines are used for controlling non-focusing photosensitive pixel units in the focusing pixel rows to read out pixel signals, and the second group of row selection control lines are used for controlling the focusing photosensitive pixel units in the focusing pixel rows to read out pixel signals.

2. The image sensor of claim 1, wherein the focus sensitive pixel cells in the pair of focus sensitive pixel cells are spaced apart by an odd number of rows.

3. The image sensor of claim 1, wherein the pair of focus sensitive pixel units are formed as green pixels in place of blue or red pixels in the bayer array.

4. The image sensor of claim 1, wherein the pair of focus sensitive pixel cells occupy 3% of the pixel array.

5. The image sensor according to claim 1, wherein the row selection control line of the nth row of pixel rows and the N-2 th row of pixel rows provided with the pair of focus-sensitive pixel units is symmetrically arranged, wherein N is a positive integer of 2 or more.

6. The image sensor of claim 5, wherein 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, respectively;

in the N-2 th row of pixel rows, the first group of row selection control lines are used for controlling pixel signals to be read out from pixel units which are positioned in the same column as the non-focal sensitive pixel units in the N-th row of pixel rows, and the second group of row selection control lines are used for controlling pixel signals to be read out from pixel units which are positioned in the same column as the focal sensitive pixel units in the N-th row of pixel rows.

7. The image sensor of claim 6, wherein the first set of row select control lines outputs a first control signal to the nth row pixel row and the N-2 th row pixel row to control readout of pixel signals by the unfocused photosensitive pixel cells in the nth row pixel row and the N-2 th row pixel row;

the second group of row selection control lines output a second control signal to the N-2 row of pixel rows to control pixel units in the N-2 row of pixel rows and the pixel units in the same column with the focusing photosensitive pixel units in the N row of pixel rows to read out pixel signals;

the second group of row selection control lines output a third control signal to the nth row of pixel rows to control the focusing photosensitive pixel units in the nth row of pixel rows to read out pixel signals.

8. The image sensor of claim 1, wherein the image sensor comprises a normal operating mode and a combined readout mode;

in the normal working mode, the first group of row selection control lines are used for controlling the non-focusing photosensitive pixel units to read out pixel signals, and the second group of row selection control lines are used for controlling the focusing photosensitive pixel units to read out pixel signals;

in the combined readout mode, the focusing pixel row does not perform readout of the pixel signals, and the pixel signals of adjacent same-color pixel units which are positioned in the same pixel row and are separated by one pixel unit are output through the same column transmission control line.

9. A reading control method of an image sensor, adapted to the image sensor according to any one of claims 1 to 8, characterized in that the method comprises the steps of:

controlling the pixel array to enter a focusing mode;

receiving an output control signal of the digital control circuit to control and select pixel units of a row to be read to read out pixel signals;

the line selection control line controls a focusing pixel line provided with the focusing photosensitive pixel unit to obtain an output value of the focusing photosensitive pixel unit to the pixel unit in the pair; wherein, the first area of one focusing photosensitive pixel unit in the focusing pixel row is controlled to read out the pixel signal and serve as a first output value; controlling a second area of another focusing photosensitive pixel unit in the focusing pixel row to read out pixel signals and serve as a second output value; the first region and the second region are complementary regions;

and performing focusing control according to the first output value and the second output value.

10. The method according to claim 9, wherein the performing focus control based on the first output value and the second output value includes:

generating a first phase value from the first output value;

generating a second phase value from the second output value;

and performing focusing control according to the first phase value and the second phase value.

11. The reading control method of an image sensor according to claim 9 or 10, characterized in that the method further comprises:

the first group of row selection control lines are used for controlling pixel units in the N-2 th row of pixel rows and the pixel units in the same column with the non-focusing photosensitive pixel units in the N-th row of pixel rows to read out pixel signals;

the second group of row selection control lines are used for controlling pixel units in the N-2 th row of pixel rows and the pixel units in the same column with the focusing photosensitive pixel units in the N-th row of pixel rows to read out pixel signals.

12. The method of reading control of an image sensor according to claim 11, characterized in that the method further comprises:

controlling the pixel array to enter a merging read-out mode;

and the readout channels of the pixel signals of the focusing pixel rows are controlled to be closed, and the pixel signals of the adjacent same-color pixel units which are positioned in the same pixel row and are separated by one pixel unit are output through the same column transmission control line, wherein the same column output control line is one column in which the adjacent same-color pixel units are positioned.