WO2022011547A1

WO2022011547A1 - Image sensor and related electronic device

Info

Publication number: WO2022011547A1
Application number: PCT/CN2020/101880
Authority: WO
Inventors: 赵维民
Original assignee: 深圳市汇顶科技股份有限公司
Priority date: 2020-07-14
Filing date: 2020-07-14
Publication date: 2022-01-20
Also published as: CN115152198B; CN115152198A

Abstract

Disclosed in the present application are an image sensor and a related electronic device. The image sensor is coupled to an image processor; the image processor establishes an image on the basis of sensing data provided by the image sensor; the image sensor comprises: a pixel array, comprising: a first floating diffusion node; and a first pixel (110_1) comprising first subpixels (r) and a second subpixel (c) that share the first floating diffusion node; each first subpixel is one of a red subpixel, a green subpixel, and a blue subpixel; the second subpixel is none of a red subpixel, a green subpixel, and a blue subpixel; and the first floating diffusion node is provided between the first subpixels and the second subpixel.

Description

Image sensors and related electronics

technical field

The present application relates to a sensor, and in particular, to an image sensor and related electronic devices.

Background technique

Image sensors have been mass-produced and applied. When evaluating the performance of an image sensor, at least the low-light sensitivity and signal-to-noise ratio of the image sensor are usually considered. Therefore, there is a need for an innovative design to improve the light-sensing capability of an image sensor in low light and at the same time improve the signal-to-noise ratio of the image sensor.

SUMMARY OF THE INVENTION

One of the objectives of the present application is to disclose a sensor, especially an image sensor and related electronic devices, to solve the above problems.

An embodiment of the present application discloses an image sensor, which is coupled to an image processor, and the image processor creates an image based on sensing data provided by the image sensor. The image sensor includes: a pixel array, including: a first a floating diffusion node; and a first pixel, including a first sub-pixel and a second sub-pixel, sharing the first floating diffusion node, the first sub-pixel is a red sub-pixel, a green sub-pixel and a blue sub-pixel One of them, wherein the second sub-pixel is not one of the red sub-pixel, the green sub-pixel and the blue sub-pixel, and the first floating diffusion node is disposed on the first sub-pixel and the first sub-pixel between two sub-pixels.

An embodiment of the present application discloses an electronic device. The electronic device includes the aforementioned image processor and image sensor.

The image sensor disclosed in the present application further improves the four-bayer pattern to reduce the degree of difference in light sensitivity among multiple pixels, thereby increasing the exposure time, thereby improving the signal-to-noise ratio of red data, green data or blue data . In addition, each of the plurality of pixels has sub-pixels with strong light-sensing ability, such as white sub-pixels, so the light-sensing ability of the image sensor under low light can also be improved.

Description of drawings

FIG. 1 is a schematic diagram of an embodiment of an image sensor of the present application.

FIG. 2 is a schematic diagram of an embodiment of a pixel group of the present application.

FIG. 3A is a schematic diagram of another embodiment of the pixel group of the present application.

FIG. 3B is a schematic diagram of yet another embodiment of the pixel group of the present application.

FIG. 4 is a schematic diagram of still another embodiment of the pixel group of the present application.

FIG. 5 is a schematic diagram of still another embodiment of the pixel group of the present application.

FIG. 6A is a timing diagram of an embodiment of a signal of the present application.

FIG. 6B is a timing diagram of another embodiment of the signal of the present application.

FIG. 7 is a timing diagram of yet another embodiment of the signal of the present application.

FIG. 8A is a timing diagram of yet another embodiment of the signal of the present application.

FIG. 8B is a timing diagram of yet another embodiment of the signal of the present application.

FIG. 9 is a timing diagram of yet another embodiment of the signal of the present application.

FIG. 10 is a timing diagram of yet another embodiment of the signal of the present application.

FIG. 11 is a schematic diagram of an embodiment in which the image processor and the image sensor shown in FIG. 1 are applied to an electronic device.

detailed description

The following disclosure provides various implementations, or illustrations, that can be used to implement various features of the present disclosure. Specific examples of components and configurations are described below to simplify the present disclosure. As can be appreciated, these descriptions are exemplary only, and are not intended to limit the present disclosure. For example, in the description below, forming a first feature on or over a second feature may include some embodiments in which the first and second features are in direct contact with each other; and may also include Certain embodiments may have additional components formed between the first and second features described above, such that the first and second features may not be in direct contact. Furthermore, the present disclosure may reuse reference numerals and/or reference numerals in various embodiments. Such reuse is for brevity and clarity, and does not in itself represent a relationship between the different embodiments and/or configurations discussed.

Furthermore, the use of spatially relative terms, such as "below", "below", "below", "above", "above" and the like, may be used to facilitate the description of the drawings. relationship between one component or feature shown with respect to another component or feature. These spatially relative terms are intended to encompass many different orientations of the device in use or operation in addition to the orientation depicted in the figures. The device may be positioned in other orientations (eg, rotated 90 degrees or at other orientations) and these spatially relative descriptors should be interpreted accordingly.

Notwithstanding that the numerical ranges and parameters setting forth the broader scope of the application are approximations, the numerical values set forth in the specific examples have been reported as precisely as possible. Any numerical value, however, inherently contains the standard deviation resulting from individual testing methods. As used herein, "same" generally means that the actual value is within plus or minus 10%, 5%, 1%, or 0.5% of a particular value or range. Alternatively, the term "same" means that the actual value lies within an acceptable standard error of the mean, as considered by one of ordinary skill in the art to which this application pertains. It should be understood that all ranges, quantities, numerical values and percentages used herein (for example, to describe material amounts, time durations, temperatures, operating conditions, quantity ratios and other similar) are modified by "same". Therefore, unless otherwise stated to the contrary, the numerical parameters disclosed in this specification and the accompanying claims are approximate numerical values and may be changed as required. At a minimum, these numerical parameters should be construed as indicating the number of significant digits and values obtained by applying ordinary rounding. Numerical ranges are expressed herein as from one endpoint to the other or between the endpoints; unless otherwise indicated, the numerical ranges recited herein are inclusive of the endpoints.

Existing pixel groups are mostly composed of Bayer patterns, for example, composed of one red pixel (R), two green pixels (G) and one blue pixel (B), abbreviated as RGGB.

In addition, recently, in order to improve the photosensitivity under low light, at least one of the pixels in the Bayer pattern is replaced by a clear pixel C (clear pixel), and other improved patterns are derived to realize pixel groups. The photosensitive ability of the clear pixel C here is higher than that of each pixel in the Bayer pattern, for example, the clear pixel C may be a white pixel (W) or a yellow pixel (Y). The derived modified pattern may consist of one red pixel, two yellow pixels (Y) and one blue pixel, abbreviated as RYYB, or, for example, one red pixel, one green pixel, one white pixel (W) and one blue pixel. Color pixel composition, referred to as RGWB.

In addition to changing the pattern of the pixel group, recently, in order to improve the flexibility of use and allow users to choose between high resolution and high signal-to-noise ratio, each pixel in the pixel group is divided into multiple sub-pixels of the same color. Shared floating diffusion nodes, such as four subpixels.

As mentioned above, since the clear pixels C have strong light-sensing ability, in order to avoid overexposure, the determination of the overall exposure time of the other improved patterns mentioned above is limited to avoid overexposure of the clear pixels C. However, the photosensitive ability of the red, green or blue pixels is only about one-half or less of that of the clear pixel C. Therefore, if the red, green or blue pixels are exposed according to the exposure time of the clear pixel C, The amount of red, green, or blue data available to a pixel group is greatly reduced, resulting in a poor signal-to-noise ratio for red, green, or blue data.

In order to solve the above problem, the present application disperses a plurality of clear sub-pixels in the clear pixel C into the red pixels R, green pixels G and blue pixels B in the same pixel group, so as to reduce the number of pixels in the pixel group. Therefore, it is possible to improve the light sensitivity in low light, and at the same time increase the data volume of red data, green data or blue data. The details are as follows.

FIG. 1 is a schematic diagram of an embodiment of an image sensor 100 coupled to an image processor 50 of the present application, wherein the image processor 50 creates an image based on sensing data provided by the image sensor 100 . 1 , the image sensor 100 includes a pixel array (not shown) composed of a plurality of pixels 110 and a control signal generating circuit 120 . For simplicity of illustration, only one pixel 110 is shown in FIG. 1 .

The pixel 110 includes a plurality of sub-pixels 112 and a pixel circuit 114, wherein the plurality of sub-pixels 112 includes sub-pixels 112_1 to 112_n, where n is a positive integer greater than 1. In this embodiment, n=4 is specifically described, that is, The pixel 110 includes four sub-pixels 112 . The sub-pixels 112_1 to 112_4 share the same floating diffusion node FD, and the floating diffusion node FD may be located between the sub-pixels 112_1 to 112_4 on the circuit layout. That is, the pixel 110 has a four-shared structure.

In some embodiments, subpixel 112 includes photodiode PD and microlens 160 (shown in FIG. 2 ). The microlens 160 is used to focus the light entering the sub-pixel 112 onto the photodiode PD, and the photodiode PD is used to convert the optical signal into an electrical signal. The photodiode PD may be a photodiode with electrons as main carriers, or a photodiode with holes as main carriers. Furthermore, it is noted that photodiode PD is intended to encompass essentially any type of photon or light detection element, such as a light gate or other photosensitive region.

The pixel circuit 114 is used to selectively couple to the sub-pixels 112_1 to 112_4 and selectively output column output signals related to the charges generated by the sub-pixels 112_1 to 112_4 to the image processor 50 , that is, the column output signals include images Sensing data provided by the sensor 100 . The pixel circuit 114 includes transfer gates 116_1 , 116_2 , 116_3 and 116_4 , a reset gate 117 , a source follower 118 , a row select gate 119 and a capacitor 120 .

The transfer gates 116_1 , 116_2 , 116_3 and 116_4 are controlled by the control signals TG1 , TG2 , TG3 and TG4 provided by the control signal generating circuit 120 respectively to selectively transfer the charges generated by the corresponding sub-pixels 112_1 to 112_4 to the floating diffusion nodes. FD. Then, through the capacitor 120 coupled between the floating diffusion node FD and the reference voltage 190, the electric energy brought by the charges is stored in the capacitor 120 to establish an initial sensing voltage at the floating diffusion node FD. The initial sensing voltage is amplified by the source follower 118 coupled to the reference voltage VDD, and the amplified sensing voltage is output at the drain of the source follower 118. The row selection gate 119 is controlled by a row selection signal SEL provided by a row selector (not shown) to selectively output the amplified sensing voltage as a column output signal to the image processor 50 . Image processor 50 builds an image based on the column output signals. The reset gate 117 is controlled by the reset signal RST provided by the control signal generating circuit 120 to selectively use the reference voltage VDD to clear the charges on the floating diffusion node FD.

A plurality of pixels 110 may constitute a single pixel group 140 (as shown in FIG. 2 ), and the pixel array may be formed by repeatedly arranging the pixel groups. In this embodiment, a single pixel group 140 is formed by four pixels 110 (ie, 110_1 , 110_2 , 110_3 and 110_4 as shown in FIG. 2 ).

The pixel group 140 of the present invention has a specific pattern, so that the difference in light sensitivity between any two pixels 110 in the same pixel group 140 is smaller than any two pixels in the comparison pixel group with the high-sensitivity pattern RGWB, so the pixel group 140 The overall exposure time of the pixel group may be longer than the overall exposure time of the comparison pixel group to increase the data amount of red data, green data or blue data. In addition, the photosensitive ability of the pixel 110 is better than that of the red pixel R, the green pixel G, or the blue pixel B, so that the photosensitive ability under low light can be improved.

Particular patterns of pixel groups 140 are illustrated in the embodiments of FIGS. 2, 3A, 3B, 4, and 5, wherein the number of clear sub-pixels c (shown in FIG. 2) of pixel 110 of FIG. 2 is less than that of FIG. 3A and 3B, which are again less than FIG. 4 . The specific pattern of FIG. 5 can be applied in phase detection autofocus, which is described in detail below.

The pattern design of the pixel group 140 determines the selection of the aforementioned signal combination. For different pattern designs of the pixel groups 140 , different signal combinations can be formed by arbitrarily adjusting the relative timings of the trigger potentials of each of the control signals TG1 , TG2 , TG3 , and TG4 and the reset signal RST. In response to different signal combinations, the pixel circuit 114 can provide column output signals representing different physical meanings. Further, the pattern design of any one of FIGS. 2 and 4 can be operated using the signal combination of FIGS. 6A, 6B, 8A or 8B, and the pattern design of FIG. 3B can be operated using the signal combination of FIGS. 7 or 9 Operation, the pattern design of FIG. 5 can be operated using the signal combination of FIG. 10 , wherein the signal combination used for the pattern design of FIG. 3A is similar to the signal combination of FIG. 7 or FIG. 9 and will not be repeated here.

In general, in the present invention, the column output signal output by the pixel circuit 114 can provide the standard red, green and blue data required for the Bayer pattern, as well as to enhance the outline of the image generated by the image processor 50 information. It should be noted that the sub-pixels 112_1 to 112_4 are continuously exposed on the entire time axis in FIGS. 6A to 10 .

FIG. 2 is a schematic diagram of an embodiment of the pixel group 140 of the present application. 2, in order to distinguish from the red pixel R, the green pixel G, the blue pixel B, the clear pixel C, the white pixel W and the yellow pixel Y, the red sub-pixel is marked as r, the green sub-pixel is marked as g, and the blue sub-pixel is marked as g. Labeled b, clear subpixels are labeled c, white subpixels are labeled w, and yellow subpixels are labeled y.

The red sub-pixel r, green sub-pixel g, and blue sub-pixel b are used in the same way as the red pixel R, green pixel G, and blue pixel B, and are used to provide the standard red data, green data and blue data.

In order to increase the light-sensing capability under low light, clear sub-pixels c are arranged in the pixel group 140 . The clear sub-pixel c is not one of the red sub-pixel r, the green sub-pixel g, and the blue sub-pixel b. The clear sub-pixel c can absorb at least two or more kinds of light in red, green and blue. Accordingly, the light-sensing ability of the clear sub-pixel c is better than that of the red sub-pixel r, the green sub-pixel g, and the blue sub-pixel b. To enhance the contour information of the image generated by the image processor 50 . In some embodiments, the clear subpixel c may be a white subpixel w, a yellow subpixel y, a cyan subpixel, or a magenta subpixel.

In order to improve the signal-to-noise ratio by improving the degree of unbalance of light sensitivity among the pixels 110_1, 110_2, 110_3 and 110_4, a clear sub-pixel c is further provided in each of the pixels 110_1 to 110_4 and the pixels 110_1 to 110_4 include the same number of Clear sub-pixel c. In this embodiment, each of the pixels 110_1 to 110_4 includes a clear sub-pixel c.

Taking the pixel 110_1 as an example, in the pixel 110_1, the upper left corner is a red subpixel r, the upper right corner is a red subpixel r, the lower left corner is a red subpixel r, and the lower right corner is a clear subpixel c, which respectively correspond to the subpixels in FIG. 1 . Pixels 112_1, 112_2, 112_3, and 112_4. The remaining pixels 110_2, 110_3, and 110_4 and so on. Accordingly, where appropriate, pixel 110_1 may be referred to as modified red pixel R'. Similarly, pixels 110_2 and 110_3 may be referred to as modified green pixel G', and pixel 110_4 may be referred to as modified blue pixel B'. In the pixel group 140 of FIG. 2, two modified green pixels G' are arranged diagonally, and one modified red pixel R' and one modified blue pixel B' are arranged diagonally.

In order to better understand that the pattern of the pixel group 140 in FIG. 2 can improve the degree of photosensitive ability imbalance among the pixels 110_1 , 110_2 , 110_3 and 110_4 , the photosensitive ability is further described quantitatively as shown in Tables 1 and 2.

Tables 1 to 2 exemplarily illustrate the difference between the present embodiment and the existing high-sensitivity pattern RGWB in terms of the balance of photosensitivity. In order to align with the structure of the pixel 110, the pixels of the comparative pixel group with the high-sensitivity pattern RGWB also use four - Realized by sharing the pixel structure. For example, in the high-sensitivity pattern RGWB, the red pixel R is composed of four red sub-pixels r, and the remaining green pixels G, blue pixels B, white pixels W and so on.

For easy understanding, the light-sensing ability of the blue sub-pixel b is taken as a reference, and the light-sensing value of the blue sub-pixel b is set to 1. Compared with the photosensitive ability of the blue sub-pixel b, the photosensitive value of the red sub-pixel r is 1.12, the photosensitive value of the green sub-pixel g is 1.4, the photosensitive value of the yellow sub-pixel y is 2, and the photosensitive value of the white sub-pixel w is 2. is 3.08.

Table 1 is used to exemplarily illustrate the average light-sensing value of the pixel group 140 in FIG. 2 .

Table I

It can be observed from Table 1 that the absolute value of the difference between the average photosensitive values of the pixels 110_3 and 110_4 is the largest, that is, 0.3, and the absolute value of the difference between the average photosensitive values of the pixels 110_2 and 110_3 is the smallest, that is, 0.

Table 2 is used to exemplarily illustrate the average photosensitive value of the comparative pixel group with the high photosensitive pattern RGWB. As described above, each pixel of the comparison pixel group is composed of sub-pixels of the same color. Therefore, the average photosensitive values of the red pixel R, green pixel G, blue pixel B, and white pixel W are the photosensitive values of the respective red subpixel r, green subpixel g, blue subpixel b, and white subpixel w, respectively.

Table II

It can be observed from Table 2 that the maximum value and the minimum value of the absolute value of the difference between any two average photosensitive values are 2.08 and 0.12, respectively.

Comparing Tables 1 and 2, it can be seen that the maximum value of the absolute value of the difference between the average photosensitive values of the pixel group 140 is smaller than that of the comparison pixel group with the high-sensitivity pattern RGWB, which means that the sensitivity of the pixel group 140 is unbalanced. get improvement. This also means that there is no specific pixel (eg, white pixel W) in the pixel group 140, and its light-sensing capability is significantly greater than that of other pixels, eg, about twice or more. Therefore, it is possible to increase the exposure time by removing the limitation caused by the white pixel W, thereby improving the signal-to-noise ratio of the red data, the green data, or the blue data.

FIG. 3A is a schematic diagram of another embodiment of the pixel group 140 of the present application. Referring to FIG. 3A , the pixel group 140 of FIG. 3A is similar to the pixel group 140 of FIG. 2 , the difference is that the number of clear sub-pixels c of a single pixel 110 of FIG. 3A is two and arranged diagonally. In this embodiment, the clear sub-pixel c is a white sub-pixel w. Table 3 is used to exemplarily illustrate the average light-sensing value of the pixel group 140 in FIG. 3A .

Table 3

It can be observed from Table 3 that the absolute value of the difference between the average photosensitive values of the pixels 110_3 and 110_4 is the largest, that is, 0.2. It can be seen from the comparison of Tables 1 and 3 that the maximum value of the absolute value of the difference between the average photosensitive values of the pixel group 140 in FIG. 3A is also smaller than that of the comparison pixel group with the high-sensitivity pattern RGWB. Therefore, it is possible to increase the exposure time by removing the limitation caused by the white pixel W, thereby improving the signal-to-noise ratio of the red data, the green data, or the blue data.

In this embodiment, the two clear sub-pixels c are disposed at the upper left and the lower right of each pixel 110, respectively. However, the present disclosure is not limited thereto. In some embodiments, the two clear sub-pixels c may be disposed at the upper right and the lower left of each pixel 110, respectively. In other embodiments, the pixel group 140 may be formed by any arrangement and combination of the foregoing two manners of disposing the clear sub-pixels c.

FIG. 3B is a schematic diagram of yet another embodiment of the pixel group 140 of the present application. Referring to FIG. 3B , the pixel group 140 of FIG. 3B is similar to the pixel group 140 of FIG. 3A , the difference is that the two clear sub-pixels c of FIG. 3B are arranged adjacently. In some embodiments, the pixel group 140 can be formed by arbitrarily arranging and combining the arrangement manner of the clear sub-pixels c in FIG. 3B and the arrangement manner of the clear sub-pixels c in FIG. 3A .

FIG. 4 is a schematic diagram of still another embodiment of the pixel group 140 of the present application. Referring to FIG. 4 , the pixel group 140 of FIG. 4 is similar to the pixel group 140 of FIG. 3B , the difference is that the number of clear sub-pixels c of a single pixel 110 of FIG. 4 is three. In this embodiment, the clear sub-pixel c is a white sub-pixel w.

Table 4 is used to exemplarily illustrate the average light-sensing value of the pixel group 140 in FIG. 4 .

Table 4

It can be observed from Table 4 that the absolute value of the difference between the average photosensitive values of the pixels 110_3 and 110_4 is the largest, that is, 0.1. It can be seen from the comparison between Tables 1 and 4 that the maximum value of the absolute value of the difference between the average photosensitive values of the pixel group 140 in FIG. 4 is smaller than that of the comparison pixel group with the high-sensitivity pattern RGWB. Therefore, it is possible to increase the exposure time by removing the limitation caused by the white pixel W, thereby improving the signal-to-noise ratio of the red data, the green data, or the blue data.

In this embodiment, the red sub-pixel r, the green sub-pixel g or the blue sub-pixel b are disposed at the lower right corner of the respective pixel 110 . However, the present disclosure is not limited thereto, and the red sub-pixel r, the green sub-pixel g or the blue sub-pixel b may be disposed at the upper left corner, the lower left corner, or the upper right corner of the respective pixel 110 . In addition, in this embodiment, the red sub-pixel r, the green sub-pixel g or the blue sub-pixel b are all disposed at the lower right corner of each pixel 110 . However, the present disclosure is not limited thereto, and the red sub-pixel r, the green sub-pixel g or the blue sub-pixel b may be disposed at different positions of the respective pixels 110 . For example, the red sub-pixel r is arranged in the upper left corner of the pixel 110_1, and the green sub-pixel g is arranged in the upper right corner of the pixel 110_2.

FIG. 5 is a schematic diagram of still another embodiment of the pixel group 140 of the present application. Referring to FIG. 5 , the pixel group 140 of FIG. 5 is similar to the pixel group 140 of FIG. 2 , except that the clear sub-pixel c of the pixel 110_1 and the green sub-pixel g of the pixel 110_2 further form a phase pixel pair. The clear sub-pixel c of the pixel 110_1 shares the elliptical microlens 162 with the green sub-pixel g of the pixel 110_2.

In other embodiments, any two types of sub-pixels 110 may form a phase pixel pair. In addition, in the embodiment in which the number of clear sub-pixels c is two or three, phase pixel pairs can also be set by analogy.

The embodiments of FIGS. 6A-10 will illustrate the details of the standard red, green, and blue data required by the pixel group 140 of FIGS. 2-5 to provide the Bayer pattern, as well as to enhance the contours of the image produced by the image processor 50 details of the information. For simplicity, in the embodiments of FIGS. 6A to 9 , the pixel 110_1 of the pixel group 140 will be taken as an example, and the remaining pixels 110_2 to 110_4 operate in the same manner.

Referring to FIG. 6A , the signals shown in FIG. 6A are used to control the pixel group 140 of FIG. 2 . Referring to FIG. 2 and FIG. 6A simultaneously, initially, before the time point t1, the control signals TG1 to TG4 and the reset signal RST are pulled to a high level. In this embodiment, the transmission gates 116_1 , 116_2 , 116_3 , and 116_4 and the reset gate 117 are positive edge-triggered elements. Therefore, the transfer gates 116_1 , 116_2 , 116_3 and 116_4 and the reset gate 117 are turned on to reset the sub-pixels 112_1 , 112_2 , 112_3 and 112_4 and reset the floating diffusion node FD. At time point t1, the voltage of the floating diffusion node FD is the reference voltage VDD.

Between time points t1 and t2, the reset signal RST is pulled to a high level again to reset the floating diffusion node FD again. At time point t2, the voltage of the floating diffusion node FD is the reference voltage VDD.

Between time points t2 and t3, the control signal generating circuit 120 generates a control signal TG4 according to the exposure time T1 of the clear sub-pixel c (corresponding to the sub-pixel 112_4 in FIG. 1 ) in the lower right corner, and pulls the control signal TG4 to a high level, so that the The charge generated by the clear sub-pixel c in the lower right corner is transferred to the floating diffusion node FD. At time point t3, the voltage of the floating diffusion node FD drops from the reference voltage VDD to a voltage (VDD-VQ4), where VQ4 is the voltage drop caused by the charges generated by the clear sub-pixel c. At this time, the row selection gate 119 is turned on, for example, in response to the high level of the row selection signal SEL, and the pixel circuit 114 outputs a column output signal based on the voltage (VDD-VQ4), which is used to improve the contour information of the image generated by the image processor 50 . It should be noted that the charges generated by the clear sub-pixel c still remain in the floating diffusion node FD without being cleared.

Between the time points t3 and t4, the control signal generating circuit 120 generates the control signals TG1 to TG3 according to the exposure time T2 of the red sub-pixel r and pulls the control signals TG1 to TG3 to a high level, so that the upper left, upper right and lower left three The charges generated by the red sub-pixel r (corresponding to the sub-pixels 112_1 to 112_3 in FIG. 1 ) are transferred to the floating diffusion node FD and accumulated with the charges generated by the clear sub-pixel c. The voltage of the floating diffusion node FD drops again to [VDD-(VQ1+VQ2+VQ3+VQ4)]. At this time, the row selection gate 119 is turned on, and the pixel circuit 114 outputs the column output signal based on the voltage [VDD-(VQ1+VQ2+VQ3+VQ4)].

For example, by subtracting the column output signal output at time point t3 and the column output signal output at time point t4 by the image processor 50, the combined and accumulated charge data of the three red sub-pixels r (ie VQ2+ VQ3+VQ4), which is the standard red data required for the Bayer pattern.

Besides, the exposure time T2 is greater than the overall exposure time used for the comparative pixel group having the high-sensitivity pattern RGWB. Therefore, the standard red data, green data and blue data collected by the pixel group 140 are more abundant than the comparison pixel group with the high-sensitivity pattern RGWB, so that the red data, green data and blue data have better signal-to-noise ratio.

In the embodiment of FIG. 6A , the column output signal related to the charge of the clear sub-pixel c is output first. However, the present disclosure is not limited thereto. In the embodiment of FIG. 6B , the column output signal for the combined accumulated charges of the three red sub-pixels r is output first. The principle of the operation according to the signal of FIG. 6B is the same as that of FIG. 6A , and will not be repeated here.

Referring to FIG. 7, the signals shown in FIG. 7 are used to control the pixel group 140 of FIG. 3B. Incidentally, the pixel groups 140 in FIG. 3A and FIG. 3B have the same number of clear sub-pixels c, so as long as the time when the control signals TG1 to TG4 are pulled to a high level is adjusted adaptively, a similar operation method can be performed. The operation is not repeated here.

At time point t3, based on the charges generated by the lower left and lower right clear sub-pixels c, the voltage of the floating diffusion node FD drops from the reference voltage VDD to the voltage [VDD-(VQ3+VQ4)], where VQ3 and VQ4 are two The voltage drop caused by the charges generated by the clear sub-pixel c. At this time, the pixel circuit 114 outputs a column output signal regarding the combined and accumulated charge data of the two clear sub-pixels c.

At time point t4 , the charges generated by the exposure of the two red sub-pixels r on the upper left and the upper right are transferred to the floating diffusion node FD, and the charges generated by the two clear sub-pixels c are combined and accumulated. The voltage of the floating diffusion node FD drops to a voltage [VDD-(VQ1+VQ2+VQ3+VQ4)], where VQ1 and VQ2 are the voltage drops caused by the charges generated by the two red sub-pixels r respectively. At this time, the pixel circuit 114 outputs the column output signal based on the voltage [VDD-(VQ1+VQ2+VQ3+VQ4)].

For example, by subtracting the column output signals output by the image processor 50 at time points t3 and t4, the charge data (ie, VQ1+VQ2) accumulated by the two red sub-pixels r can be calculated.

In the embodiment of FIG. 7 , the column output signal related to the charge of the clear sub-pixel c is output first. However, the present disclosure is not limited thereto. In some embodiments, the column output signal regarding the charge of the red sub-pixel r may also be output first.

In the embodiments of FIGS. 8A , 8B and 9 , the operation mode of combining accumulated charges is not adopted. Therefore, it is not necessary to use mathematical operations to calculate the charge data of, for example, the red sub-pixel r and the clear sub-pixel c.

Referring to FIG. 8A , the signals shown in FIG. 8A are used to control the pixel group 140 of FIG. 2 . Referring to FIG. 2 and FIG. 8A at the same time, the operations before the time point t3 are the same as those in FIG. 6A , which will not be repeated here. Between time points t3 and t4, the reset signal RST is pulled to a high level to turn on the reset gate 117, and the charges of the clear sub-pixel c collected by the floating diffusion node FD in response to the control signal TG4 are cleared. The floating diffusion node FD is reset from the voltage (VDD-VQ4) to the reference voltage VDD.

Between time points t4 and t5, the control signal generating circuit 120 generates control signals TG1 to TG3 according to the exposure time T2 of the upper left, upper right and lower left red sub-pixels r, and pulls the control signals TG1 to TG3 to a high level, so that the three The charges generated by the red sub-pixels r are transferred to the floating diffusion node FD for integration and accumulation. The floating diffusion node FD drops from the reference voltage VDD to [VDD-(VQ1+VQ2+VQ3)]. At this time, the row selection gate 119 is turned on, and the pixel circuit 114 outputs the column output signal based on the voltage [VDD-(VQ1+VQ2+VQ3)].

To put it simply, in the embodiment of FIG. 8A , the column output signal related to the charge of the clear sub-pixel c is output first. However, the present disclosure is not limited thereto. For example, in the embodiment of FIG. 8B , the column output signal related to the charge of the red sub-pixel r is output first. The principle of operation according to the signal of FIG. 8B is the same as that of FIG. 8A , and details are not repeated here.

Referring to FIG. 9, the signals shown in FIG. 9 are used to control the pixel group 140 of FIG. 3B. At time t3, based on the combined accumulated charges of the lower left and lower right clear sub-pixels c, the voltage of the floating diffusion node FD drops from the reference voltage VDD to a voltage [VDD-(VQ3+VQ4)], where VQ3 and VQ4 are respectively The voltage drop caused by the charges generated by the two clear sub-pixels c. At this time, the pixel circuit 114 outputs a column output signal regarding the combined accumulated charges of the two clear sub-pixels c. At time point t4, the combined accumulated charges of the two clear sub-pixels c at the floating diffusion node FD are cleared, and the floating diffusion node FD is reset to the reference voltage VDD. At time point t5, based on the combined accumulated charges of the two red sub-pixels r, the voltage of the floating diffusion node FD drops from the reference voltage VDD to a voltage [VDD-(VQ1+VQ2)], where VQ1 and VQ2 are the two red sub-pixels respectively The voltage drop caused by the charge generated by the pixel r. At this time, the pixel circuit 114 outputs the column output signal based on the voltage [VDD-(VQ1+VQ2)].

To put it simply, in the embodiment of FIG. 9 , the column output signal related to the charge of the clear sub-pixel c is output first. However, the present disclosure is not limited thereto. In some embodiments, the column output signal regarding the charge of the red sub-pixel r may also be output first.

Referring to FIG. 10 , the signals shown in FIG. 10 are used to control the pixel group 140 of FIG. 5 . In FIG. 5 , the clear sub-pixel c and the green sub-pixel g forming the phase detection pixel pair are located in two different sub-pixels 110_1 and 110_2 . Accordingly, at least the two sub-pixels 110_1 and 110_2 need to perform operations according to the signals in FIG. 10 to obtain two phase detection data required by the phase detection auto-focus function, which are respectively described below.

As far as the pixel 110_1 is concerned, referring to FIG. 5 and FIG. 10 at the same time, the operations before the time point t3 are the same as those in FIG. 6A , which will not be repeated here. Between the time points t3 and t4, the control signal generating circuit 120 generates the control signal TG3 according to the exposure time T2 of the red sub-pixel r in the lower left corner and pulls the control signal TG3 to a high level, so that the charges generated by the red sub-pixel r and the floating The diffusion node FD collects the charges of the clear sub-pixel c collected in response to the control signal TG4 by combining and accumulating. At time point t4, based on the combined accumulated charges of the clear sub-pixel c and the red sub-pixel r, the voltage of the floating diffusion node FD drops from the voltage (VDD-VQ4) to the voltage [VDD-(VQ3+VQ4)], where VQ3 and VQ4 is the voltage drop caused by the charges generated by the red sub-pixel r and the clear sub-pixel c, respectively. At this time, the pixel circuit 114 outputs the column output signal based on the voltage [VDD-(VQ3+VQ4)].

Between time points t4 and t5, the control signal generating circuit 120 generates control signals TG1 and TG2 according to the exposure time T3 of the red sub-pixel r in the upper left and upper right corners, and pulls the control signals TG1 and TG2 to a high level, so that the upper left The charges generated by the red sub-pixels r in the corner and the upper right corner are combined and accumulated again with the combined accumulated charges on the floating diffusion node FD. At time point t5, based on the aforementioned recombination of the accumulated charges, the voltage of the floating diffusion node FD drops from the voltage [VDD-(VQ3+VQ4)] to the voltage [VDD-(VQ1+VQ2+VQ3+VQ4)], where VQ1 and VQ2 is the voltage drop caused by the charges generated by the red sub-pixel r in the upper left corner and the upper right corner, respectively. At this time, the pixel circuit 114 outputs the column output signal based on the voltage [VDD-(VQ1+VQ2+VQ3+VQ4)]. It should be noted that, the exposure time difference between the exposure times T2 and T3 is shown in an exaggerated manner in FIG. 10 , and in some embodiments, the exposure time difference is not significant. This means that VQ1 and VQ2 are similar to VQ3.

For example, the image processor 50 can determine the charge data of the first phase detection pixel (ie, the clear sub-pixel c of the pixel 110_1 ) based on the column output signal at the time point T3 . Next, the image processor 50 performs mathematical operations on the column output signals at the time points T3 , T4 and T5 to calculate the combined and accumulated charge data of the three red sub-pixels r.

As far as the pixel 110_2 is concerned, referring to FIG. 5 and FIG. 10 at the same time, the operations before the time point t3 are the same as those in FIG. 6A , and are not repeated here. It should be noted that VQ4 at time point t3 is the voltage drop caused by the charge generated by the clear sub-pixel c, but the clear sub-pixel c in the pixel 110_2 is not used as a phase detection pixel, so VQ4 cannot be used as a phase detection pixel. Pixel charge data. Between time points t3 and t4, the control signal TG3 is pulled to a high level, so that the charges generated by the green sub-pixel g (ie, the second phase detection pixel) in the lower left corner and the floating diffusion node FD are clearly collected in response to the control signal TG4 The charge of the sub-pixel c is combined and accumulated. Accordingly, the pixel circuit 114 outputs the column output signal based on the voltage [VDD-(VQ3+VQ4)], where VQ3 and VQ4 are the voltage drop caused by the charges generated by the green sub-pixel g and the clear sub-pixel c in the lower left corner, respectively. The operation of the pixel 110_2 at the remaining time points is the same as that of the pixel 110_1. Next, the image processor 50 performs mathematical operations on the column output signals at the time points T3 , T4 and T5 to calculate the combined and accumulated charge data of the three green sub-pixels g.

In addition, for example, the image processor 50 can calculate the charge data of the green sub-pixel g (ie, the second phase detection pixel) in the lower left corner by performing mathematical operations based on the column output signals at the time points T3 and T4. Obtain the charge data of the second phase detection pixel. Next, the image processor 50 can complete the phase detection auto-focusing function based on the charge data of the clear sub-pixel c at the lower right corner of the pixel 110_1 and the green sub-pixel g at the lower left corner of the pixel 110_2.

The signals shown in FIG. 10 are for illustration only. For various pixel group patterns, as long as the signals of the charge data of the phase detection pixels are obtained by combining accumulation and mathematical operations, they all fall into the scope of the present application.

FIG. 11 is a schematic diagram of an embodiment in which the image processor 50 and the image sensor 100 shown in FIG. 1 are applied to the electronic device 60 . 6, the electronic device 60 may be any electronic device such as a smart phone, a personal digital assistant, a handheld computer system, or a tablet computer.

The foregoing description briefly sets forth features of certain embodiments of the application, so that those skilled in the art to which this application pertains can more fully understand the various aspects of the present disclosure. It should be apparent to those skilled in the art to which this application pertains that they can readily use the present disclosure as a basis to design or modify other processes and structures for carrying out the same purposes and/or of the embodiments described herein achieve the same advantages. Those with ordinary knowledge in the technical field to which this application belongs should understand that these equivalent embodiments still belong to the spirit and scope of the present disclosure, and various changes, substitutions and alterations can be made without departing from the spirit of the present disclosure. with scope.

Claims

An image sensor, coupled to an image processor, the image processor builds an image based on sensing data provided by the image sensor, the image sensor comprising:

Pixel array, including:

a first floating diffusion node; and

The first pixel includes a first sub-pixel and a second sub-pixel, sharing the first floating diffusion node, and the first sub-pixel is one of a red sub-pixel, a green sub-pixel and a blue sub-pixel, wherein the The second sub-pixel is not one of the red sub-pixel, the green sub-pixel and the blue sub-pixel, and the first floating diffusion node is disposed between the first sub-pixel and the second sub-pixel.
The image sensor of claim 1, wherein the pixel array further comprises:

a second floating diffusion node; and

The second pixel includes a third sub-pixel and a fourth sub-pixel that share the second floating diffusion node, the third sub-pixel is one of a red sub-pixel, a green sub-pixel and a blue sub-pixel, the The color of the third subpixel is different from that of the first subpixel, wherein the fourth subpixel is not one of a red subpixel, a green subpixel, and a blue subpixel.
The image sensor of claim 2, wherein the second sub-pixel and the fourth sub-pixel have the same photosensitive capability.
4. The image sensor of claim 3, wherein the second sub-pixel and the fourth sub-pixel have better photosensitivity than the red sub-pixel, the green sub-pixel or the blue sub-pixel.
5. The image sensor of claim 4, wherein the first pixel has a first average sensitivity value, the second pixel has a second average sensitivity value, and a difference between the first average sensitivity value and the second average sensitivity value is The absolute value is smaller than the absolute value of the difference between the light-sensing values of the red sub-pixel, the green sub-pixel and the blue sub-pixel.
The image sensor of claim 3, wherein the second subpixel and the fourth subpixel are both white subpixels.
The image sensor of claim 1, wherein the number of the second sub-pixels is the same as the number of the fourth sub-pixels.
The image sensor of claim 1, wherein the first pixel includes three of the first sub-pixels and one of the second sub-pixels in a 2*2 arrangement, and the second pixel includes three of the second sub-pixels The third sub-pixel and one of the fourth sub-pixels are arranged at 2*2.
The image sensor of claim 1 , wherein the first pixel includes two of the first sub-pixels and two of the second sub-pixels are arranged in a 2*2 arrangement, and the second pixel includes two of the second sub-pixels. The third sub-pixel and the two fourth sub-pixels are arranged by 2*2.
9. The image sensor of claim 9, wherein two of the first sub-pixels are arranged adjacently or diagonally, and two of the third sub-pixels are arranged adjacently or diagonally, and.
The image sensor of claim 1, wherein the first pixel includes one of the first sub-pixels and three of the second sub-pixels are arranged in 2*2, and the second pixel includes one of the first sub-pixels The three sub-pixels and the three fourth sub-pixels are arranged in 2*2.
The image sensor of claim 1, further comprising:

A control circuit is shared by the first sub-pixel and the second sub-pixel, wherein the control circuit is used for:

generating a first control signal according to a first exposure time to control the output of charges of one of the first sub-pixel and the second sub-pixel to the first floating diffusion node; and

According to the second exposure time, a second control signal is generated to control the other one of the first sub-pixel and the second sub-pixel to output charges to the first floating diffusion node, so as to communicate with the first floating diffusion node The diffusion node combines and accumulates charges collected in response to the first control signal.
The image sensor of claim 1, further comprising:

A control circuit is shared by the first sub-pixel and the second sub-pixel, wherein the control circuit is used for:

generating a first control signal according to a first exposure time, so as to control the electric charge of one of the first sub-pixel and the second sub-pixel to be output to the first floating diffusion node;

generating a reset signal to clear the reset of the charges collected by the first floating diffusion node in response to the first control signal; and

According to the second exposure time, a second control signal is generated to control the other one of the first sub-pixel and the second sub-pixel to output charges to the first floating diffusion node.
13. The image sensor according to any one of claims 12 or 13, wherein the first exposure time and the second exposure time are determined according to the first average light sensitivity value and the second average light sensitivity value.
The image sensor of claim 1 , wherein the second sub-pixel and the fourth sub-pixel are used to enhance contour information of the image.
The image sensor of claim 1, wherein the pixel array further comprises:

the third floating diffusion node;

The third pixel includes a fifth sub-pixel and a sixth sub-pixel, sharing the third floating diffusion node, the fifth sub-pixel is one of a red sub-pixel, a green sub-pixel and a blue sub-pixel, the the color of the fifth subpixel is different from the first subpixel and the third subpixel; and

the fourth floating diffusion node;

The fourth pixel includes a seventh sub-pixel and an eighth sub-pixel, sharing the fourth floating diffusion node, the seventh sub-pixel is one of a red sub-pixel, a green sub-pixel and a blue sub-pixel, the The color of the seventh subpixel is different from that of the first subpixel and the third subpixel, and is the same as that of the fifth subpixel.
17. The image sensor of claim 16, wherein the seventh subpixel and the fifth subpixel are green subpixels.
4. The image sensor of claim 1, wherein the second subpixel serves as a first phase detection pixel in a phase pixel pair, and the third subpixel serves as a second phase detection pixel in the phase pixel pair pixel.
An electronic device, comprising:

the image processor; and

The image sensor of any of claims 1-18.