WO2022027657A1

WO2022027657A1 - Pixel array for image sensor, image sensor, and electronic device

Info

Publication number: WO2022027657A1
Application number: PCT/CN2020/107969
Authority: WO
Inventors: 张玮; 李顺展; 王炳文; 王磊
Original assignee: 深圳市汇顶科技股份有限公司
Priority date: 2020-08-07
Filing date: 2020-08-07
Publication date: 2022-02-10
Also published as: CN114391248B; CN114391248A

Abstract

The present application provides a pixel array for an image sensor, an image sensor, and an electronic device. In the pixel array for an image sensor, a photosensitive surface comprises a plurality of pixel units arranged in an array; each pixel unit comprises a plurality of pixels arranged in an array; the plurality of pixels comprise a plurality of color pixels and at least one white pixel; the color pixels are used to transmit light wavelength bands corresponding to their own colors; the white pixel is used to transmit visible light in a full wavelength band. The pixel array for an image sensor provided in the present application can improve the photographing performance of an image sensor in a low-light environment, and improve the imaging quality of the image sensor.

Description

Pixel array of image sensor, image sensor and electronic device

technical field

The present application relates to the field of semiconductor technology, and in particular, to a pixel array of an image sensor, an image sensor, and an electronic device.

Background technique

Image sensors, such as charge coupled device image sensors (Charge Coupled Device, referred to as: CCD) or complementary metal oxide semiconductor (Complementary Metal Oxide Semiconductor, referred to as: CMOS), use the photoelectric conversion function of photoelectric devices to convert optical images into Digital signal sensor, which is widely used in mobile terminals, digital products, security monitoring and other fields.

Whether it is CCD or CMOS, photosensitive elements are used to collect images. The core of the photosensitive elements of CCD or CMOS is a photodiode. The photodiode generates an output current after receiving light irradiation, and the output analog signal is converted into a digital signal. The signal is output after post-processing by the image processor; among them, each photosensitive element corresponds to a pixel in the image sensor. Since the photosensitive element can only sense the intensity of light and cannot capture color information, a color filter must be covered above the photosensitive element. The most common practice is to cover the RGB red, green and blue color filters. A color pixel is composed of four pixels in a 1:2:1 configuration (that is, the red and blue filters cover one pixel respectively, and the remaining two pixels both cover the green filter).

However, in mobile devices, due to the limited size of the image sensor, the photosensitive area of the pixel is also limited, and the amount of light entering the image sensor is affected by the color filter, which will affect the performance of taking pictures in low-light environments.

SUMMARY OF THE INVENTION

The present application provides a pixel array of an image sensor, an image sensor and an electronic device, so as to improve the photographing performance of the image sensor in a low-light environment and improve the imaging quality of the image sensor.

In a first aspect, the present application provides a pixel array of an image sensor, the pixel array includes a plurality of pixel units arranged in an array on a photosensitive surface, each pixel unit is arranged with a plurality of pixels in an array, and the plurality of pixels includes a plurality of A color pixel and at least one white pixel, the color pixel is used to transmit the light band corresponding to its own color, and the white pixel is used to transmit the visible light of the whole wavelength band.

In a specific embodiment of the present application, each pixel unit includes a plurality of pixel groups arranged in an array, and the plurality of pixel groups include a first pixel group and a second pixel group adjacent in the row direction and a pixel group located in an adjacent row and a third pixel group and a fourth pixel group adjacent to the first pixel group and the second pixel group respectively in the column direction;

Wherein, at least one of the first pixel group, the second pixel group, the third pixel group and the fourth pixel group has white pixels.

In a specific embodiment of the present application, other color pixels except white pixels in each pixel group are the same color, and the color pixels in the second pixel group and the third pixel group are the same color, and the first pixel The color pixels in the group and the fourth pixel group are different in color and different from the second pixel group and the third pixel group.

In a specific embodiment of the present application, the color pixels in the first pixel group are red pixels, the color pixels in the second pixel group and the third pixel group are green pixels, and the color pixels in the fourth pixel group are blue pixels color pixels.

In a specific embodiment of the present application, the white pixels are evenly spaced in a plurality of pixel units.

In a specific implementation manner of the present application, each pixel group includes only one pixel.

In a specific embodiment of the present application, each pixel group includes a plurality of pixels arranged in a matrix, and each pixel group includes at least one white pixel.

In a specific implementation manner of the present application, the rows and columns of each pixel group are equal.

In a specific embodiment of the present application, each pixel group includes four pixels, nine pixels or sixteen pixels.

In a specific embodiment of the present application, each pixel group includes one white pixel, and white pixels in adjacent pixel groups have intervals.

In a specific embodiment of the present application, each pixel group includes two white pixels, and the two white pixels are diagonally displaced.

In a specific embodiment of the present application, the white pixels are located at the corners of the pixel groups, and the white pixels corresponding to adjacent pixel groups are arranged adjacently.

In a specific embodiment of the present application, at least one pixel group includes four white pixels that are adjacent to each other in pairs.

In a specific embodiment of the present application, the pixel array includes a filter layer, and the filter layer includes a red filter part, a green filter part, a blue filter part, a red filter part, a green filter part, a blue filter and white filter.

In a specific embodiment of the present application, the pixel array further includes a micro-lens group, and the micro-lens group is disposed on the photosensitive side of the filter layer.

In a specific embodiment of the present application, the micro-lens group includes a plurality of first lenses and a plurality of second lenses, and each of the first lenses covers each of the red pixels, the green pixels, the blue pixels, and the white pixels arranged at intervals, Each second lens covers two adjacent four white pixels.

In a specific embodiment of the present application, the pixel array further includes a semiconductor substrate and a dielectric layer disposed on the semiconductor substrate, and the filter layer and the microlens group are sequentially stacked on the dielectric layer.

In a specific embodiment of the present application, a photodiode is provided in the semiconductor substrate corresponding to each pixel.

In a specific embodiment of the present application, an isolation portion is provided between adjacent pixels, and the isolation portion is used to prevent light leakage between adjacent pixels.

In a specific embodiment of the present application, the pixel array includes an effective pixel area and a non-photosensitive area located at the periphery of the effective pixel area, and a plurality of pixel units uniformly cover the effective pixel area.

In a second aspect, the present application provides an image sensor, the image sensor includes a readout circuit, an image processor, an output interface, and the pixel array of the image sensor described in any of the above, the pixel array, the readout circuit, and the image processor be electrically connected to the output interface in sequence;

The readout circuit is used to convert the analog signal collected by the pixel array into a digital signal, the image processor is used to process the digital signal, and the output interface is used to output the processed digital signal.

In a specific embodiment of the present application, the image processor is configured to output the digital signal of each pixel unit of the pixel array as a color pixel signal and a white pixel signal;

The processing modes of the image processor for digital signals include full resolution mode and high sensitivity mode, wherein the full resolution mode is used to output each pixel signal in each pixel unit independently, and the high sensitivity mode is used to output each pixel signal. The pixel signals of the same color in the pixel unit are combined and output.

In a third aspect, the present application provides an electronic device including the image sensor as described above.

The pixel array of the image sensor, the image sensor and the electronic device provided by the present application, the pixel array of the image sensor is composed of a plurality of pixel units arranged in an array on its photosensitive surface, and a plurality of pixels arranged in an array in each pixel unit At least one white pixel is set in the image sensor, and the white pixel can transmit visible light in the whole band. Therefore, by setting the white pixel, the amount of light entering the pixel array can be increased, especially when the image sensor is in a low-light environment. Setting white pixels increases the amount of light entering the pixel array, and at the same time improves the focusing performance of the pixel array, thereby improving the photographing performance of the image sensor in a low-light environment, and improving the imaging quality of the sensor.

Description of drawings

In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following will briefly introduce the accompanying drawings used in the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description are Some examples of this application. For those of ordinary skill in the art, other drawings can also be obtained from these drawings without creative effort.

1 is a schematic layout diagram of a pixel unit in a pixel array in the prior art;

2 is a schematic layout diagram of a pixel unit in another pixel array in the prior art;

3 is a schematic layout diagram of a pixel unit in a third type of pixel array in the prior art;

4 is a schematic layout diagram of a pixel unit in a fourth pixel array in the prior art;

5 is a schematic layout diagram of a pixel unit of a pixel array according to Embodiment 1 of the present application;

6a-6d are schematic layout diagrams of pixel units in another pixel array provided in Embodiment 1 of the present application;

7a-7c are schematic layout diagrams of pixel units in a third pixel array provided in Embodiment 1 of the present application;

8a-8c are schematic layout diagrams of pixel units in a fourth pixel array provided in Embodiment 1 of the present application;

FIG. 9a is a schematic diagram of a partial structure of a pixel array according to Embodiment 1 of the present application;

FIG. 9b is a schematic partial structure diagram of another pixel array provided in Embodiment 1 of the present application;

10 is a plan layout diagram of a pixel array provided in Embodiment 1 of the present application;

FIG. 11 is a schematic diagram of an image sensor according to Embodiment 2 of the present application;

12a is a schematic diagram of signal processing in a full resolution mode of an image processor according to Embodiment 2 of the present application;

Fig. 12b is a schematic diagram of signal processing in the high sensitivity mode of the image processor provided in the second embodiment of the present application.

Description of reference numbers:

1-pixel unit; 11-pixel group; 11a-first pixel group; 11b-second pixel group; 11c-third pixel group; 11d-fourth pixel group; 111-red pixel; 112-green pixel; 113- blue pixel; 114-white pixel; 2-filter layer; 21-red filter part; 22-green filter part; 23-blue filter part; 24-white filter part; 3-micro lens group; 31-first lens; 32-second lens; 4-semiconductor substrate; 41-photodiode; 5-dielectric layer; 6-isolation;

A-effective pixel area; B-non-photosensitive area;

100-image sensor; 110-pixel array; 120-readout circuit; 130-image processor; 140-output interface; 150-system control unit; 160-power management unit.

detailed description

In order to make the purposes, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments It is a part of the embodiments of the present application, but not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the protection scope of the present application.

Nowadays, with the development trend of mobile devices such as mobile phones and tablet computers becoming more and more thin and light, the internal structure of the mobile device is relatively compact, and the setting of the image sensor in the mobile device is limited. However, on the basis of a certain size of the image sensor, mobile devices pursue high pixels that can bring high-resolution image quality and large pixels that bring high-sensitivity and low-noise image quality in dark states. It is rather contradictory.

Whether it is a CCD sensor or a CMOS sensor, to collect color images, it is necessary to collect a variety of basic colors. Generally, different colors are collected by setting filters of different colors to transmit light of different colors. In order to facilitate the design and manufacture of optical filters, a Bayer Color Filter Array (Bayer Color Filter Array, referred to as Bayer Array) is usually used to acquire color images.

Specifically, the Bayer array sets different colors on one filter, that is, the filters of different colors are concentrated on one filter, and the filter has filter parts of different colors. The filter array is arranged.

However, due to the limited size of the image sensor in mobile devices, the photosensitive area of the pixel array is usually limited. Especially in low-light environments, the amount of light entering the image sensor is affected by the Bayer array, which affects the photographing performance of the image sensor. The focus and resolution of the image sensor affect the imaging quality of the image sensor.

Therefore, embodiments of the present application provide a pixel array of an image sensor, an image sensor, and an electronic device, so as to improve the photographing performance of the image sensor in a low-light environment and improve the imaging quality of the image sensor.

The technical solutions of the present application will be described in detail below with specific examples. The following specific embodiments may be combined with each other, and the same or similar concepts or processes may not be repeated in some embodiments.

Example 1

5 is a schematic layout diagram of a pixel unit in a pixel array provided in Embodiment 1 of the present application; FIGS. 6a-6d are schematic layout diagrams of pixel units in another pixel array provided in Embodiment 1 of the present application; FIGS. 7a- 7c is a schematic layout diagram of a pixel unit in a third type of pixel array provided in Embodiment 1 of the present application; FIGS. 8a-8c are schematic layout diagrams of a pixel unit in a fourth type of pixel array provided in Embodiment 1 of the present application; A schematic diagram of a partial structure of a pixel array provided in Embodiment 1 of the present application; FIG. 9b is a schematic diagram of a partial structure of another pixel array provided in Embodiment 1 of the present application.

Referring to FIGS. 5 to 8 c , the pixel array of the image sensor (hereinafter referred to as the pixel array) provided by this embodiment includes a plurality of pixel units 1 arranged in an array on the photosensitive surface. A plurality of pixels are arranged in the array, and the plurality of pixels include a plurality of color pixels and at least one white pixel 114. The color pixels are used to transmit light bands corresponding to their own colors, and the white pixels 114 are used to transmit visible light in all wavelength bands.

As shown in FIGS. 5 to 8 c , the pixel array of this embodiment includes a plurality of pixel units 1 , and the plurality of pixel units 1 are arranged in a matrix. Specifically, the pixel unit 1 can be used as a basic photosensitive unit in a pixel array, and a plurality of pixel units 1 arranged in a matrix form a photosensitive surface of the pixel array, and color images are collected through the plurality of pixel units 1 .

Exemplarily, the pixel unit 1 may be the smallest repeating unit in a pixel array, and the pixel array is composed of a plurality of repeating pixel units 1 arranged in a matrix. For example, the matrix constituting the pixel array includes a plurality of pixel units 1 of M (positive integer greater than or equal to 2) rows and N (positive integers greater than or equal to 2) columns.

Wherein, each pixel unit 1 includes a plurality of pixels arranged in an array. In order to form a color image, the plurality of pixels include a plurality of color pixels, and the color pixels may specifically include pixels of different colors. According to the colors of different color pixels, the corresponding color pixels can transmit light bands corresponding to their own colors. For example, the red pixel 111 is used to transmit red light, and the green pixel 112 is used to transmit green light.

Since the color pixels only transmit light corresponding to their own color, the light input of the color pixels in the pixel unit 1 is relatively low, especially in a low-light environment, the light input of the pixel array composed of only color pixels will be affected. If it is larger, this will reduce the performance of the pixel array such as the resolution and focusing function, and then affect the photographing performance of the image sensor, and the resolution and sharpness of the image sensor will be lower.

Therefore, in this embodiment, each pixel unit 1 has at least one white pixel 114 , and the white pixel 114 can transmit visible light in the full wavelength band, which can increase the amount of light entering the pixel unit 1 , especially in a low-light environment It can compensate the brightness collected by the pixel array, improve the photosensitive ability of the pixel array, enhance its resolution and focusing function and other performance, thereby improving the photographing performance of the image sensor, so that the color image obtained by the image sensor has higher quality.

In a possible implementation, each pixel unit 1 may include a plurality of pixel groups 11, and the plurality of pixel groups 11 may include a first pixel group 11a and a second pixel group 11b that are adjacent in the row direction, and The third pixel group 11c and the fourth pixel group 11d which are adjacent to the first pixel group 11a and the second pixel group 11b in the column direction are adjacent to each other.

In this embodiment, each pixel unit 1 is composed of a plurality of pixel groups 11, and the plurality of pixel groups 11 are arranged in an array. Specifically, each pixel unit 1 includes a first pixel group 11a, a second pixel group 11b, a third pixel group 11c and a fourth pixel group 11d, and the four pixel groups 11 may include the same number of pixels, and the The arrangement of the four pixel groups 11 is the same.

The first pixel group 11a and the second pixel group 11b are located in the same row and adjacent, and the third pixel group 11c and the fourth pixel group 11d are adjacent and arranged adjacent to the first pixel group 11a and the second pixel group 11b row, the first pixel group 11a and the third pixel group 11c are located in the same column, the second pixel group 11b and the fourth pixel group 11d are displaced in the same column, that is, the first pixel group 11a and the fourth pixel group 11d are arranged on top of each other. The second pixel group 11b and the third pixel group 11c are disposed on top of each other.

The first pixel group 11a, the second pixel group 11b, the third pixel group 11c and the fourth pixel group 11d arranged in rows and columns constitute one pixel unit 1, and a plurality of pixel units 1 arranged in an array constitute the entire pixel array. Among all the pixels included in the first pixel group 11 a , the second pixel group 11 b , the third pixel group 11 c and the fourth pixel group 11 d , at least one pixel is a white pixel 114 .

In a specific implementation manner, other color pixels except the white pixel 114 in each pixel group 11 are of the same color, and the color pixels in the second pixel group 11b and the third pixel group 11c have the same color, and the first pixel group 11c has the same color. The color pixels in the pixel group 11a and the fourth pixel group 11d are different in color and different from the second pixel group 11b and the third pixel group 11c.

The pixel group 11 is the basic structural unit of the pixel unit 1. In the case where the white pixel 114 is not provided, the pixels in each pixel group 11 are pixels of the same color, and the colors of the pixels in the adjacent pixel groups 11 may be the same or different. .

Specifically, the color pixels in the second pixel group 11b and the third pixel group 11c arranged opposite to each other have the same color, while the other first pixel group 11a and the fourth pixel group 11d arranged opposite to each other have the same color The colors of the pixels are different, and the colors of the color pixels in the first pixel group 11a and the fourth pixel group 11d are different from the colors of the color pixels in the second pixel group 11b and the third pixel group 11c.

1 is a schematic layout diagram of a pixel unit in a pixel array in the prior art; FIG. 2 is a schematic layout diagram of a pixel unit in another pixel array in the prior art; FIG. 3 is a third type of pixel in the prior art. Schematic diagram of the layout of the pixel units in the array; FIG. 4 is a schematic diagram of the layout of the pixel units in the fourth type of pixel array in the prior art.

Referring to Figures 1 to 4, for a color image, it is necessary to collect a variety of basic colors, such as three basic colors of red (R), green (G), and blue (B). Unit 1 needs to set pixels capable of collecting three colors of R, G, and B corresponding to the colors, ie, red pixels 111 , green pixels 112 and blue pixels 113 .

Since human eyes are more sensitive to green, the number of green pixels 112 set in the pixel unit 1 may be more than the number of red pixels 111 and blue pixels 113 . The number of green pixels 112 may be roughly the sum of the numbers of red pixels 111 and blue pixels 113, that is, the color pixels in the first pixel group 11a may be red pixels 111, which are arranged on top of the first pixel group 11a. The color pixels in the fourth pixel group 11 d may be blue pixels 113 , and the color pixels in the second pixel group 11 b and the third pixel group 11 c disposed on top of each other may be green pixels 112 .

The red pixels 111 in the pixel unit 1 are used to transmit red light, the green pixels 112 are used to transmit green light, and the blue pixels 113 are used to transmit blue light. In specific applications, filters corresponding to the pixel colors can be set. to transmit light of the corresponding color. Among them, the red filter is used to transmit red light, the green filter is used to transmit green light, and the blue filter is used to transmit blue light.

If the red filter, the green filter and the blue filter are separately set to correspond to the pixels of the three colors of R, G, and B, it is necessary to set multiple filters, which is expensive and inconvenient to manufacture. In order to solve this problem, referring to FIG. 1 to FIG. 4 , the pixel array can be set as a Bayer Color Filter Array (Bayer Color Filter Array, referred to as: Bayer Array).

The Bayer array is to set different colors on a filter, for example, set three colors of R, G, B, and these three colors correspond to the color pixels of the corresponding colors, which can improve the production efficiency of the pixel array, reduce the production cost and Different colored parts of the filter can better align the pixels of the corresponding color.

Referring to FIGS. 5 to 8 c , the pixel array of this embodiment can be improved by improving the Bayer array to increase the amount of light entering the pixel array, thereby improving the photographing performance of the image sensor in a low-light environment, and improving the imaging quality of the image sensor. .

Specifically, in the pixel array of the present embodiment, by setting white (visible light in the full wavelength band) in the filter in the form of Bayer array, the white part corresponds to the white pixel 114, that is, the original R, G, B replaces at least one of the three colors with white (W).

It should be noted that, after replacing other color pixels with white pixels 114, the layout form in which the green pixels 112 are roughly the sum of the red pixels 111 and the blue pixels 113 can still be maintained, so as to satisfy the sensitivity of human eyes to different colors. need.

While increasing the amount of incoming light of the pixel array, in order to improve the uniformity of incoming light of the pixel array, in a possible implementation manner, the white pixels 114 may be uniformly arranged in the plurality of pixel units 1 . In the entire pixel array composed of a plurality of pixel units 1, the white pixels 114 can be evenly spaced in the pixel array, so that the light entering the pixel array as a whole is relatively uniform, which can improve the uniformity of the imaging of the image sensor, thereby improving the imaging of the image sensor. quality.

Referring to FIG. 1, FIG. 1 is a layout structure of a classic Bayer array, with R, G, and B as the basic colors, and consists of a red pixel 111, a blue pixel 113 and two opposite each other. The green pixels 112 constitute one pixel unit 1 .

Corresponding to the classic Bayer array shown in FIG. 1 , as shown in FIG. 5 , in each pixel unit 1 of the pixel array provided in this embodiment, each pixel group 11 of the pixel unit 1 includes only one pixel, and the pixel The unit 1 consists of four pixels arranged in an array. Among the four pixels constituting the pixel unit 1 , at least one pixel is a white pixel 114 .

Exemplarily, for each pixel unit 1, the pixel unit 1 may have various layout forms, for example, the pixel unit 1 may be composed of four pixels of R, G, B, W, or composed of R, G and two W, Or it is composed of R, B and two Ws, or it is composed of G, B and two Ws, or it is composed of any one pixel of R, G, B and three Ws in different forms; wherein, for the white pixel 114 in the The position in the pixel unit 1 is not specifically limited.

In order to improve the resolution, photosensitivity and other performance of the pixel array and reduce the noise of the pixel array, as shown in Figure 2 to Figure 4, on the basis of the classic Bayer array, a multi-pixel combination of 11 pixels for each color has been developed. The layout form of the Bayer array formed by the arrangement, that is, in the pixel array, each color area includes a plurality of pixels of the color arranged in the array. In this way, a high-resolution pixel array can be formed, and at the same time, the pixel array also has the performance of high sensitivity and low noise in the dark state.

For example, as shown in Figure 2, in the pixel array, each color area is composed of 4 pixel arrays; as shown in Figure 3, each color area is composed of 9 pixel arrays; 4, each color area is composed of 16 pixel arrays. It can be understood that each color region may also be formed by arranging and combining more pixel arrays, which is not limited in this embodiment.

6a to 8c, in the pixel array of this embodiment, corresponding to the layout of the Bayer array shown in FIGS. 2 to 4, each pixel group 11 constituting each pixel unit 1 in this embodiment It may also include a plurality of pixels arranged in a matrix, and the plurality of pixels in each pixel group 11 include at least one white pixel 114 , so as to increase the amount of light entering each pixel unit 1 by arranging the white pixel 114 .

Referring to FIGS. 6 a to 6 d , in a specific implementation manner, each pixel group 11 may include four pixels, and the four pixels are arranged in two rows and two columns. That is, four pixels are combined into one pixel group 11 , wherein the four pixels in each pixel group 11 include at least one white pixel 114 .

Exemplarily, as shown in FIG. 6a, each pixel group 11 may include one white pixel 114, and the white pixels 114 in adjacent pixel groups 11 are spaced apart from each other, in order to improve the distribution uniformity of the white pixels 114. 6a as an example, the white pixels 114 may be located at the corners of each pixel group 11 in the same direction, for example, the white pixels 114 are located in the lower right corner of each pixel group 11 . In such a pixel unit 1, the number of white pixels 114 is 25% of the total number of pixels.

As shown in FIG. 6 b , each pixel group 11 may include two white pixels 114 , and the two white pixels 114 are diagonally displaced. Taking the paper direction shown in FIG. 6b as an example, two white pixels 114 may be located at the upper left corner and the lower right corner of each pixel group 11, respectively; or, two white pixels 114 may be located at the upper right corner of each pixel group 11, respectively corner and lower left corner. In such a pixel unit 1, the number of white pixels 114 is 50% of the total number of pixels.

As shown in FIG. 6c, for the layout form in which four pixels form one pixel group 11, in the four pixel groups 11, four pixels in one pixel group 11 may all be white pixels 114, and the four white pixels 114 are adjacent to each other. The setting is equivalent to forming a four-in-one white pixel group.

As shown in FIG. 6d, each pixel group 11 may include one white pixel 114, and the white pixels 114 in the four pixel groups 11 are arranged adjacently. Taking one pixel group 11 as an example, the white pixels 114 are located at the corners of the pixel group 11 adjacent to other pixel groups 11 , so four white pixels 114 are also equivalent to forming a four-in-one white pixel group.

In the layout form of the pixel unit 1 shown in FIG. 6c and FIG. 6d, in one pixel unit 1, the number of white pixels 114 is 25% of the total number of pixels.

Referring to FIGS. 7 a to 7 c , in a specific implementation manner, each pixel group 11 may include nine pixels, and the nine pixels are arranged in three rows and three columns. That is, nine pixels are combined into one pixel group 11 , wherein the nine pixels in each pixel group 11 include at least one white pixel 114 .

Exemplarily, as shown in FIG. 7a, each pixel group 11 includes one white pixel 114, and the white pixel 114 is located at the corner of the pixel group 11, and the white pixels 114 corresponding to adjacent pixel groups 11 are arranged adjacently. In this way, the four white pixels 114 can be equivalent to forming a four-in-one white pixel group. In such a pixel unit 1, the number of white pixels 114 is 1/9 of the total number of pixels.

As shown in FIG. 7 b , each pixel group 11 includes two white pixels 114 , and the two white pixels 114 are respectively arranged at two opposite corners of the pixel group 11 , and the adjacent four pixel groups 11 are The corresponding white pixels 114 are arranged adjacently, and the four adjacent pixel groups 11 located at the corners of the adjacent four pixel groups 11 may be equivalent to forming a four-in-one white pixel group. In such a pixel unit 1, the number of white pixels 114 is 2/9 of the total number of pixels.

As shown in FIG. 7c, at least one pixel group 11 may include four white pixels 114 that are adjacent to each other in pairs. For example, each pixel group 11 includes four white pixels 114 that are adjacent to each other. For example, taking the paper direction in FIG. 7c as an example, the four white pixels 114 in each pixel group 11 are located on the right lower corner. In such a pixel unit 1, the number of white pixels 114 is 4/9 of the total number of pixels.

Referring to FIGS. 8 a to 8 c , in a specific implementation manner, each pixel group 11 may include sixteen pixels, and the sixteen pixels are arranged in four rows and four columns. That is, sixteen pixels are combined into one pixel group 11 , wherein the sixteen pixels in each pixel group 11 include at least one white pixel 114 .

Exemplarily, as shown in FIG. 8a, the middle of each pixel group 11 includes four white pixels 114 that are adjacent to each other. In one pixel unit 1, the number of white pixels 114 is 1/4 of the total number of pixels; as As shown in FIG. 8b , one white pixel 114 is disposed at each of the four corners of each pixel group 11 , and the opposite corners of the adjacent four pixel groups 11 form four white pixels 114 adjacent to each other. One pixel unit 1 , the number of white pixels 114 is 1/4 of the total number of pixels; as shown in FIG. 8c , the middle of each pixel group 11 includes four white pixels 114 adjacent to each other, and the adjacent pixel groups 11 are formed For the four white pixels 114 that are adjacent to each other, in one pixel unit 1, the number of the white pixels 114 is 4/9 of the total number of pixels.

It should be understood that, with reference to FIGS. 5 to 8 c , only some achievable arrangements of the pixel units 1 of the pixel array in this embodiment are exemplified, and the pixel units 1 in this embodiment include But not limited to the above arrangement.

In addition, taking each pixel group 11 in the pixel unit 1 including at most sixteen pixels arranged in four rows and four columns as an example, by designing the number and position of the white pixels 114 in each pixel unit 1, one pixel In unit 1, the ratio of the number of white pixels 114 to the total number of pixels may be between 1/16-15/16, which is not specifically limited in this embodiment.

In this embodiment, by arranging white pixels 114 in each pixel unit 1 , the light input amount of each pixel unit 1 is increased, thereby increasing the light input amount of the pixel array. For example, by setting 25% white pixels 114 in pixel unit 1, the light input of the entire image sensor will be increased by about 30%; by setting 50% white pixels 114 in pixel unit 1, the light input of the entire image sensor will be increased 60% or so.

FIG. 9a is a schematic diagram of a partial structure of a pixel array according to Embodiment 1 of the present application; FIG. 9b is a schematic diagram of a partial structure of another pixel array according to Embodiment 1 of the present application. As shown in FIG. 9a and FIG. 9b, in this embodiment, the pixel array may further include a filter layer 2, and the filter layer 2 may include a filter layer 2 corresponding to the red pixel 111, the green pixel 112, the blue pixel 113 and the white pixel 114, respectively. Red filter part 21 , green filter part 22 , blue filter part 23 and white filter part 24 .

As mentioned above, in this embodiment, the pixel array can use an integral filter layer 2 similar to the Bayer array. The filter layer 2 is provided with filter parts of different colors, and the red pixels 111 and the green pixels 112 are distributed on the filter layer 2 . , corresponding to the blue pixel 113 and the white pixel 114 , the filter part on the filter layer 2 includes a red filter part 21 , a green filter part 22 , a blue filter part 23 and a white filter part 24 . Among them, the red filter part 21 is used to transmit red light, the green filter part 22 is used to transmit green light, the blue filter part 23 is used to transmit blue light, and the white filter part 24 is used to transmit all wavelengths of light. visible light.

As shown in Fig. 9a and Fig. 9b, in a possible implementation manner, the pixel array may further include a microlens group 3, and the microlens group 3 is arranged on the photosensitive side of the filter layer 2. By arranging the microlens group 3 on the photosensitive side of the filter layer 2 , the light entering the pixel array enters the filter layer 2 after passing through the microlens group 3 . In this way, before the incident light passes through the light filtering layer 2, the light is concentrated by the microlens group 3, which can increase the amount of light entering the pixel array and increase the brightness, thereby improving the utilization rate of the incident light by the array substrate, and the output is relatively high. High quality color images.

It should be noted that a microlens refers to a lens with a small size, and usually refers to a lens with a diameter of a micrometer or even a nanometer, so that the microlens matches the size of each pixel in the pixel unit 1 .

For the pixel array provided in this embodiment, the micro-lens group 3 may specifically include a plurality of first lenses 31 and a plurality of second lenses 32 , and each of the first lenses 31 covers each of the red pixels 111 , the green pixels 112 , and the blue pixels 113 As well as the white pixels 114 arranged at intervals, each of the second lenses 32 covers the four white pixels 114 that are adjacent to each other in pairs.

As shown in FIG. 9a, for the red pixel 111, the green pixel 112 and the blue pixel 113 in the pixel group 11, in this embodiment, the first lens 31 is used to cover the filter part of the corresponding color, and each pixel above Both cover one first lens 31, that is, the first lens 31 corresponds to a single pixel, and the size of the first lens 31 corresponds to the size of a single pixel.

In addition, for each of the white pixels 114 arranged at intervals, that is, each of the white pixels 114 that are not adjacent, the white filter portion 24 corresponding to such white pixels 114 also covers the first lens 31, that is, the first lens 31 covers a separate Set the white pixel to 114.

As shown in FIG. 9b, for the four white pixels 114 that are adjacent to each other in the pixel unit 1 as shown in FIG. 6c to FIG. 8c, the four white pixels 114 can be covered by the second lens 32, that is, by A second lens 32 covers the entire four white pixels 114 .

The four white pixels 114 covered by the second lens 32, because the second lens 32 completely covers the center of the four white pixels 114, and there is no uncovered area at the opposite corners of the four white pixels 114, so the second lens The effect of 32's concentrated light is better. By arranging four white pixels 114 adjacent to each other, and correspondingly arranging the second lens 32 to completely cover the four white pixels 114, the amount of incoming light can be further increased by about 10%.

It should be understood that this embodiment is not limited to setting four adjacent white pixels 114 in pairs, but also can set adjacent nine white pixels 114 in three rows and three columns or sixteen adjacent white pixels 114 in four rows and four columns, etc. As for the layout structure, by arranging a lens whose size matches the entire area of the adjacent white pixels 114 , the light input amount of the pixel array is further increased, which will not be repeated here.

As shown in FIG. 9a and FIG. 9b, in this embodiment, the pixel array may further include a semiconductor substrate 4 and a dielectric layer 5 disposed on the semiconductor substrate 4, and the filter layer 2 and the microlens group 3 are sequentially stacked on the dielectric layer 5 Above; wherein, a photodiode 41 is provided in the semiconductor substrate 4 corresponding to each pixel.

The semiconductor substrate 4 serves as the basic carrying structure of the pixel array, and the rest of the components of the pixel array are arranged on the semiconductor substrate 4 . The semiconductor substrate 4 is provided with a photodiode 41, and each pixel of the photodiode 41 is correspondingly arranged. The photodiode 41 can generate an output current after receiving light irradiation. The intensity of the current corresponds to the intensity of the light, and the photodiode 41 outputs an electrical signal.

The dielectric layer 5 is disposed on the semiconductor substrate 4, that is, the dielectric layer 5 is located between the microlens group 3 and the semiconductor substrate 4. The dielectric layer 5 is mainly used to maintain the gate capacitance of the photodiode 41, and the dielectric layer 5 also has a noise reduction effect. .

In addition, since each pixel is used to transmit light corresponding to its color, and adjacent pixels may have different colors and transmit light of different colors, the adjacent two pixels are the red pixel 111 and the blue pixel 113 as an example , the red pixel 111 is used to transmit red light, and the blue pixel 113 is used to transmit blue light. In order to prevent light leakage between adjacent pixels, as shown in FIG. 9a and FIG. 9b, in a possible implementation manner, an isolation portion 6 may be provided between adjacent pixels.

By arranging the isolation part 6 between adjacent pixels, the isolation part 6 can prevent the light entering a certain pixel from leaking to the adjacent pixels, which can ensure that each pixel has good filter performance, thereby improving the imaging quality of the image sensor . Exemplarily, the isolation portion 6 may be made of a semiconductor material, and the isolation portion 6 may be provided in the filter layer 2 and the semiconductor substrate 4 between adjacent pixels; wherein the isolation portion 6 in the filter layer 2 and the semiconductor substrate The material of the spacer 6 in 4 may be the same or different.

FIG. 10 is a plan layout diagram of a pixel array according to Embodiment 1 of the present application. As shown in FIG. 10 , in this embodiment, the pixel array may include an effective pixel area A and a non-photosensitive area B located at the periphery of the effective pixel area A, and a plurality of pixel units 1 cover the effective pixel area A uniformly.

The pixel array includes an effective pixel area A and a non-photosensitive area B. The effective pixel area A is an area that can receive light and display a color image. The non-sensitive area B is an area surrounding the effective pixel area A, that is, the non-sensitive area B is located in the pixel. The edge area of the array, the non-photosensitive area B, is the area that cannot be exposed to light and cannot display an image. In this embodiment, each pixel unit 1 is evenly distributed in the effective pixel area A, and covers the entire effective pixel area A.

In the pixel array of the image sensor provided in this embodiment, by arranging at least one white pixel in the plurality of pixels arrayed in each pixel unit in the plurality of pixel units arranged in the array on the photosensitive surface of the pixel unit, the white pixel can be Through the visible light of the whole band, the light input of the pixel array can be increased by setting white pixels, especially when the image sensor is in a low light environment, the light input has a significant enhancement effect. At the same time, the focusing performance of the pixel array can also be improved, thereby improving the photographing performance of the image sensor in a low-light environment, and improving the imaging quality of the sensor.

Embodiment 2

FIG. 11 is a schematic diagram of an image sensor according to Embodiment 2 of the present application. As shown in FIG. 11 , this embodiment provides an image sensor 100 . The image sensor includes a readout circuit 120 , an image processor 130 , an output interface 140 , and the pixel array 110 described in Embodiment 1. The pixel array 110 , a readout The circuit 120, the image processor 130 and the output interface 140 are electrically connected in sequence; the readout circuit 120 is used to convert the analog signal collected by the pixel array 110 into a digital signal, the image processor 130 is used to process the digital signal, and the output interface 140 is used to output the processed digital signal.

In the image sensor 100 of this embodiment, the light collection signal is firstly received through the pixel array 110, and the current output signal is generated by the photodiode in the pixel array 110. Generally, the electrical signal output by the photodiode is an analog signal, and then passed through the readout circuit. 120 converts the analog signal into a corresponding digital signal, and then processes the digital signal by the image processor 130, for example, the image processor 130 performs linear correction, noise removal, dead pixel removal, interpolation, white balance and automatic on the digital signal. Exposure and other processing; after the digital signal is processed by the image processor 130 , it is output through the output interface 140 .

As shown in FIG. 11 , the image sensor 100 further includes a system control unit 150 and a power management unit 160 , the system control unit 150 performs system control on the image sensor 100 , and the power management unit 160 controls the working voltage and working current of the image sensor 100 , etc. parameter.

12a is a schematic diagram of signal processing in the full resolution mode of the image processor 130 according to the second embodiment of the present application; FIG. 12b is a schematic diagram of signal processing in the high sensitivity mode of the image processor 130 according to the second embodiment of the present application.

In this embodiment, the image processor 130 is configured to output the digital signal of each pixel unit of the pixel array 110 as a color pixel signal and a white pixel signal. As shown in FIG. 12a and FIG. 12b, in a possible implementation, the processing mode of the digital signal by the image processor 130 may include a full resolution mode and a high sensitivity mode, wherein the full resolution mode is used for each Each pixel signal in the pixel unit is output separately, and the high-sensitivity mode is used to combine the pixel signals of the same color in each pixel unit for output.

As shown in FIG. 12a, taking the pixel unit shown in FIG. 6a as an example, for the full resolution mode of the image processor 130, by individually outputting each pixel signal in each pixel unit, the pixel unit is restored to have The classical Bayer array of R, G, and B pixels and a white pixel array 110 with the same resolution process the data of the RGB pixels through the main control image processing unit at the back end.

In full resolution mode, a higher resolution image signal can be obtained by separately processing each pixel signal in the pixel unit.

As shown in FIG. 12b, continuing to take the pixel unit shown in FIG. 6a as an example, for the high sensitivity mode of the image processor 130, all pixels of the same color in the pixel unit are combined and output, for example, three red pixels are Combined output, combined output of three blue pixels, combined output of green pixels in two pixel groups respectively, combined to form a Bayer array with R, G, B pixels, combined 4 white pixels and output one with the same resolution The white pixel array 110 processes the data of the RGB pixels through the main control image processing unit at the back end.

The high-sensitivity mode can obtain image signals with stronger sensitivity by combining and outputting pixels of the same color.

It should be understood that, for the nine-in-one pixel unit shown in FIG. 7a to FIG. 7c and the sixteen-in-one pixel unit shown in FIG. The full resolution mode or the high sensitivity mode of the image processor 130 performs data processing, which will not be repeated here.

Embodiment 3

Further, on the basis of the foregoing embodiments, this embodiment provides an electronic device, where the electronic device includes the image sensor described in the second embodiment.

Wherein, in this embodiment, the electronic device may specifically be a smart phone, a camera, a tablet computer, and other mobile devices with an imaging function.

In this embodiment, the pixel array in the image sensor of the electronic device is designed, and at least one white pixel is arranged in the plurality of pixels arranged in the array in each pixel unit of the pixel array, and the white pixel can transmit visible light in the whole waveband, Therefore, by setting white pixels, the light input of the pixel array can be increased, especially when the image sensor is in a low-light environment, the light input has a significant enhancement effect. By setting white pixels to increase the light input of the pixel array, it can also improve the pixel array. The focusing performance of the image sensor can be improved, and the photographing performance of the image sensor in low light environment can be improved, and the imaging quality of the sensor can be improved.

Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, but not to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: The technical solutions described in the foregoing embodiments can still be modified, or some or all of the technical features thereof can be equivalently replaced; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the technical solutions of the embodiments of the present application. Scope.

Claims

A pixel array of an image sensor, characterized in that, the pixel array includes a plurality of pixel units arranged in an array on a photosensitive surface, and each pixel unit is arranged with a plurality of pixels in an array, and the plurality of pixels are arranged in an array. It includes a plurality of color pixels and at least one white pixel, the color pixel is used to transmit the light band corresponding to its own color, and the white pixel is used to transmit the visible light of the whole wavelength band.
The pixel array of an image sensor according to claim 1, wherein each of the pixel units comprises a plurality of pixel groups arranged in an array, and the plurality of the pixel groups comprise first pixel groups adjacent in a row direction and a second pixel group, and a third pixel group and a fourth pixel group located in adjacent rows and adjacent to the first pixel group and the second pixel group in the column direction, respectively;

Wherein, at least one of the first pixel group, the second pixel group, the third pixel group and the fourth pixel group has the white pixels.
The pixel array of the image sensor according to claim 2, wherein the color pixels other than the white pixels in each of the pixel groups are of the same color, and the second pixel group and all the color pixels are of the same color. The color pixels in the third pixel group have the same color, and the color pixels in the first pixel group and the fourth pixel group have different colors and are different from the second pixel group and the third pixel. Group.
The pixel array of the image sensor according to claim 3, wherein the color pixels in the first pixel group are red pixels, and the color pixels in the second pixel group and the third pixel group are red pixels. The color pixels are green pixels, and the color pixels in the fourth pixel group are blue pixels.
The pixel array of an image sensor according to any one of claims 1 to 4, wherein the white pixels are evenly arranged in a plurality of the pixel units.
The pixel array of the image sensor according to claim 4, wherein each of the pixel groups includes only one of the pixels.
The pixel array of the image sensor according to claim 4, wherein each of the pixel groups includes a plurality of the pixels arranged in a matrix, and each of the pixel groups includes at least one of the white pixels .
The pixel array of the image sensor according to claim 7, wherein the rows and columns of each of the pixel groups are equal.
The pixel array of an image sensor according to claim 8, wherein each of the pixel groups includes four pixels, nine pixels or sixteen pixels.
The pixel array of the image sensor according to claim 8, wherein each pixel group includes one of the white pixels, and there is a space between the white pixels in the adjacent pixel groups.
The pixel array of the image sensor according to claim 8, wherein each pixel group includes two of the white pixels, and the two white pixels are diagonally displaced.
The pixel array of the image sensor according to any one of claims 7-9, wherein the white pixels are located at the corners of the pixel groups, and the white pixels corresponding to adjacent pixel groups are adjacent to each other set up.
The pixel array of the image sensor according to any one of claims 7-9, wherein at least one of the pixel groups includes four of the white pixels that are adjacent to each other in pairs.
The pixel array of the image sensor according to any one of claims 4-13, wherein the pixel array comprises a filter layer, and the filter layer comprises pixels corresponding to the red pixels, green pixels and blue pixels respectively A red filter, a green filter, a blue filter, and a white filter provided with white pixels.
The pixel array of the image sensor according to claim 14, characterized in that, the pixel array further comprises a micro-lens group, and the micro-lens group is arranged on the photosensitive side of the filter layer.
The pixel array of the image sensor according to claim 15, wherein the micro-lens group comprises a plurality of first lenses and a plurality of second lenses, and each of the first lenses covers each of the red pixels and green pixels , blue pixels and each of the white pixels arranged at intervals, and each of the second lenses covers the four adjacent white pixels.
The pixel array of the image sensor according to claim 16, wherein the pixel array further comprises a semiconductor substrate and a dielectric layer disposed on the semiconductor substrate, the filter layer and the microlens group are stacked in sequence on the dielectric layer.
The pixel array of the image sensor according to claim 17, wherein a photodiode is provided in the semiconductor substrate corresponding to each pixel.
The pixel array of the image sensor according to any one of claims 14-18, wherein an isolation portion is provided between adjacent pixels, and the isolation portion is used to prevent light leakage between adjacent pixels.
The pixel array of the image sensor according to any one of claims 1-19, wherein the pixel array comprises an effective pixel area and a non-photosensitive area located at the periphery of the effective pixel area, and a plurality of the pixel units uniformly cover all the pixel units. Describe the effective pixel area.
An image sensor, characterized in that it comprises a readout circuit, an image processor, an output interface, and a pixel array of the image sensor according to any one of claims 1-20, wherein the pixel array, the readout circuit, and the image processor be electrically connected to the output interface in sequence;

Wherein, the readout circuit is used to convert the analog signal collected by the pixel array into a digital signal, the image processor is used to process the digital signal, and the output interface is used to output the processed digital signal.
The image sensor according to claim 21, wherein the image processor is configured to output the digital signal of each pixel unit of the pixel array as a color pixel signal and a white pixel signal;

The processing modes of the digital signal by the image processor include a full-resolution mode and a high-sensitivity mode, wherein the full-resolution mode is used to individually output each pixel signal in each of the pixel units, The high-sensitivity mode is used to combine pixel signals of the same color in each of the pixel units and output them.
An electronic device, characterized by comprising the image sensor according to claim 21 or 22.