CN114391248B

CN114391248B - Pixel array of image sensor, image sensor and electronic device

Info

Publication number: CN114391248B
Application number: CN202080036875.0A
Authority: CN
Inventors: 张玮; 李顺展; 王炳文; 王磊
Original assignee: Shenzhen Goodix Technology Co Ltd
Current assignee: Shenzhen Goodix Technology Co Ltd
Priority date: 2020-08-07
Filing date: 2020-08-07
Publication date: 2024-02-27
Anticipated expiration: 2040-08-07
Also published as: CN114391248A; WO2022027657A1

Abstract

The application provides a pixel array of an image sensor, the image sensor and an electronic device. The pixel array of the image sensor comprises a plurality of pixel units which are arranged in an array manner on a light sensitive surface, a plurality of pixels are arranged in each pixel unit in an array manner, each pixel comprises a plurality of color pixels and at least one white pixel, each color pixel is used for transmitting light wave bands corresponding to own colors, and each white pixel is used for transmitting visible light of all wave bands. The pixel array of the image sensor can improve photographing performance of the image sensor in a low illumination environment and improve imaging quality of the image sensor.

Description

Pixel array of image sensor, image sensor and electronic device

Technical Field

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

Background

An image sensor, such as a charge coupled device image sensor (Charge Coupled Device, abbreviated as CCD) or a complementary metal oxide semiconductor (Complementary Metal Oxide Semiconductor, abbreviated as CMOS), is a sensor for converting an optical image into a digital signal by using a photoelectric conversion function of a photoelectric device, and is widely used in the fields of mobile terminals, digital products, security monitoring, and the like.

The CCD or CMOS is used for collecting images, the core of the CCD or CMOS is a photodiode, the photodiode generates output current after receiving light irradiation, the output analog signal is converted into a digital signal, and the digital signal is output after post-processing by an image processor; each photosensitive element corresponds to one pixel point in the image sensor, and the photosensitive element can only sense the intensity of light and cannot capture color information, so that a color filter is required to be covered above the photosensitive element, and the most common method is to cover an RGB red, green and blue filter. A color pixel is formed by four pixels in a 1:2:1 configuration (i.e., red and blue filters cover one pixel respectively, and the remaining two pixels cover green filters).

However, since the size of the image sensor is limited, the photosensitive area of the pixels is limited, and the light incoming amount of the image sensor is affected by the color filter, which affects photographing performance in a low light environment.

Disclosure of Invention

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

In a first aspect, the present application provides a pixel array of an image sensor, where the pixel array includes a plurality of pixel units arranged in an array on a photosurface, and a plurality of pixels are arranged in each pixel unit in an array, where the plurality of pixels includes a plurality of color pixels and at least one white pixel, the color pixels are configured to transmit light bands corresponding to colors of the color pixels, and the white pixels are configured to transmit visible light in all bands.

In one specific embodiment of the present application, each pixel unit includes a plurality of pixel groups arranged in an array, the plurality of pixel groups including a first pixel group and a second pixel group adjacent in a row direction, 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 a 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 white pixels.

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

In one 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.

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

In one embodiment of the present application, only one pixel is included in each pixel group.

In one 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 one embodiment of the present application, the rows and columns of each pixel group are equal.

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

In one embodiment of the present application, each pixel group includes one white pixel, and there is a space between the white pixels in adjacent pixel groups.

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

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

In one embodiment of the present application, at least one pixel group includes four white pixels adjacent to each other.

In one embodiment of the present application, the pixel array includes a filter layer including a red filter portion, a green filter portion, a blue filter portion, and a white filter portion disposed corresponding to the red pixel, the green pixel, the blue pixel, and the white pixel, respectively.

In one embodiment of the present application, the pixel array further includes a microlens set disposed on the photosensitive side of the filter layer.

In a specific embodiment of the present application, the microlens assembly includes a plurality of first lenses and a plurality of second lenses, each first lens covers each red pixel, each green pixel, each blue pixel, and each white pixel disposed at intervals, and each second lens covers every 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 set are sequentially stacked on the dielectric layer.

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

In one embodiment of the present application, a spacer is disposed between adjacent pixels, and the spacer is used to prevent light leakage between the adjacent pixels.

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

In a second aspect, the present application provides an image sensor, the image sensor comprising a readout circuit, an image processor, an output interface, and a pixel array of the image sensor as described in any one of the preceding claims, the pixel array, the readout circuit, the image processor, and the output interface being electrically connected in sequence;

the image processor is used for processing the digital signals, and the output interface is used for outputting the processed digital signals.

In one 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 image processor processes the digital signals in a full resolution mode and a high sensitivity mode, wherein the full resolution mode is used for independently outputting each pixel signal in each pixel unit, and the high sensitivity mode is used for outputting the pixel signals with the same color in each pixel unit after being combined.

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

The pixel array of the image sensor, the image sensor and the electronic device provided by the application, among a plurality of pixel units arranged on the light sensitive surface of the pixel array of the image sensor, at least one white pixel is arranged in a plurality of pixels arranged in an array mode in each pixel unit, and the white pixel can transmit full-band visible light, so that the light inlet quantity of the pixel array can be increased through the arrangement of the white pixel, particularly the light inlet quantity of the image sensor in a low-illumination environment has a remarkable enhancement effect, the focusing performance of the pixel array can be improved while the light inlet quantity of the pixel array is increased through the arrangement of the white pixel, further the photographing performance of the image sensor in the low-illumination environment can be improved, and the imaging quality of the sensor is improved.

Drawings

In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, a brief description will be given below of the drawings that are needed in the embodiments or the prior art descriptions, and it is obvious that the drawings in the following description are some embodiments of the present application. Other figures may be derived from these figures without inventive effort for a person of ordinary skill in the art.

FIG. 1 is a schematic diagram of a pixel unit layout in a pixel array according to the prior art;

FIG. 2 is a schematic diagram showing a layout of pixel units in another pixel array according to the prior art;

FIG. 3 is a schematic layout of a pixel unit in a third pixel array according to the prior art;

FIG. 4 is a schematic layout of a pixel unit in a fourth pixel array according to the prior art;

fig. 5 is a schematic layout diagram of a pixel unit of a pixel array according to a first embodiment of the present disclosure;

fig. 6 a-6 d are schematic layouts of pixel units in another pixel array according to the first embodiment of the present disclosure;

fig. 7a-7c are schematic layout diagrams of pixel units in a third pixel array according to a first embodiment of the present disclosure;

fig. 8a-8c are schematic layouts of pixel units in a fourth pixel array according to the first embodiment of the present application;

FIG. 9a is a schematic diagram of a pixel array according to a first embodiment of the present disclosure;

FIG. 9b is a schematic diagram illustrating a partial structure of another pixel array according to the first embodiment of the present disclosure;

FIG. 10 is a plan view of a pixel array according to an embodiment of the present disclosure;

fig. 11 is a schematic diagram of an image sensor according to a second embodiment of the present disclosure;

fig. 12a is a schematic diagram of signal processing in full resolution mode of an image processor according to a second embodiment of the present disclosure;

fig. 12b is a schematic diagram of signal processing in a high sensitivity mode of an image processor according to a second embodiment of the present application.

Reference numerals illustrate:

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

a-an effective pixel region; b-a non-photosensitive area;

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

Detailed Description

For the purposes of making the objects, technical solutions and advantages of the embodiments of the present application more clear, the technical solutions of the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is apparent that the described embodiments are some embodiments of the present application, but not all embodiments. All other embodiments, which can be made by one of ordinary skill in the art based on the embodiments herein without making any inventive effort, are intended to be within the scope of the present application.

Nowadays, with the trend of mobile devices such as mobile phones and tablet computers becoming thinner, the internal structure of the mobile device is compact, and the arrangement of an image sensor in the mobile device is limited. However, on the basis of the fixed size of the image sensor, the mobile device is pursuing a high pixel capable of bringing high resolution image quality and a large pixel with high sensitivity and low noise image quality in a dark state, which is a comparatively contradictory existence for the image sensor of the mobile device.

For both CCD sensors and CMOS sensors, it is necessary to collect a plurality of most basic colors for color image collection, and different colors are generally collected by providing filters of different colors to transmit light of different colors. To facilitate the design and manufacture of the filter, a Bayer color filter array (Bayer Color Filter Array, simply referred to as Bayer array) is generally used to implement color image acquisition.

Specifically, the Bayer array is to set different colors on one filter, that is, the filters with different colors are concentrated on one filter, and the filters are provided with filter parts with different colors, and the filter parts with different colors are arranged in an array.

However, since the size of the image sensor is limited, the photosensitive area of the pixel array is also limited, and especially in a low-light environment, the light incoming amount of the image sensor is affected by the Bayer array, so that the photographing performance of the image sensor is affected, the functions of focusing, resolution and the like of the image sensor are affected, and the imaging quality of the image sensor is further affected.

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

The technical scheme of the present application is described in detail below with specific examples. The following embodiments may be mutually coupled, and some embodiments may not be repeated for the same or similar concepts or processes.

Example 1

Fig. 5 is a schematic layout diagram of a pixel unit of a pixel array according to a first embodiment of the present disclosure; fig. 6 a-6 d are schematic layouts of pixel units in another pixel array according to the first embodiment of the present disclosure; fig. 7a-7c are schematic layout diagrams of pixel units in a third pixel array according to a first embodiment of the present disclosure; fig. 8a-8c are schematic layouts of pixel units in a fourth pixel array according to the first embodiment of the present application; FIG. 9a is a schematic diagram of a pixel array according to a first embodiment of the present disclosure; fig. 9b is a schematic partial structure diagram of another pixel array according to the first embodiment of the present application.

Referring to fig. 5 to 8c, the pixel array of the image sensor (hereinafter referred to as a pixel array) provided in this embodiment includes a plurality of pixel units 1 arranged in an array on a photosensitive surface, a plurality of pixels are arranged in each pixel unit 1 in an array, the plurality of pixels include a plurality of color pixels and at least one white pixel 114, the color pixels are used for transmitting light bands corresponding to the colors of the pixels, and the white pixels 114 are used for transmitting visible light in all bands.

As shown in fig. 5 to 8c, the pixel array of the present 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 may 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 acquired by the plurality of pixel units 1.

The pixel unit 1 may be, for example, a minimum repeating unit in a pixel array constituted by a plurality of repeating pixel units 1 arranged in a matrix. For example, a matrix constituting the pixel array includes a plurality of pixel units 1 in M (positive integer of 2 or more) rows and N (positive integer of 2 or more) columns.

Wherein each pixel unit 1 comprises a plurality of pixels arranged in an array, and in order to form a color image, the plurality of pixels comprise a plurality of color pixels, and the color pixels can specifically comprise pixels with different colors. Depending on the colors of the different color pixels, the corresponding color pixels can transmit light bands corresponding to the colors of the pixels. 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 the colors of the color pixels, the light incoming amount of the color pixels in the pixel unit 1 is low, especially in a low-light environment, the light incoming amount of the pixel array formed by the color pixels is greatly affected, which reduces the resolution and focusing functions of the pixel array, and further affects the photographing performance of the image sensor, and the resolution and the definition of the image sensor are low.

Therefore, in this embodiment, each pixel unit 1 has at least one white pixel 114, and the white pixel 114 can transmit full-band visible light, so that the light incoming quantity of the pixel unit 1 can be increased, especially in a low-light environment, the brightness collected by the pixel array can be compensated, the photosensitivity of the pixel array can be improved, the performances such as resolution and focusing function can be enhanced, and further the photographing performance of the image sensor can be improved, so that the color image obtained by the image sensor has higher quality.

In one possible embodiment, each pixel unit 1 may include a plurality of pixel groups 11, and the plurality of pixel groups 11 may include first and second pixel groups 11a and 11b adjacent in the row direction and third and fourth pixel groups 11c and 11d located in adjacent rows and adjacent to the first and second pixel groups 11a and 11b, respectively, in the column direction.

In the present embodiment, each pixel unit 1 is constituted by 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, where the four pixel groups 11 may include the same number of pixels, and the four pixel groups 11 are arranged in the same manner.

The first pixel group 11a and the second pixel group 11b are located in the same row and are adjacent, the third pixel group 11c and the fourth pixel group 11d are adjacent and are arranged in adjacent rows of the first pixel group 11a and the second pixel group 11b, 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 by the same column, that is, the first pixel group 11a and the fourth pixel group 11d are arranged in a opposite manner, and the second pixel group 11b and the third pixel group 11c are arranged in a opposite manner.

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

In one embodiment, the color pixels of each pixel group 11 except for the white pixel 114 are the same color, and the color pixels of the second pixel group 11b and the third pixel group 11c are the same, and the color pixels of the first pixel group 11a and the fourth pixel group 11d are different from the second pixel group 11b and the third pixel group 11c.

The pixel groups 11 are basic constituent units of the pixel unit 1, and when the white pixels 114 are not provided, the pixels in each pixel group 11 are the same color, and the colors of the pixels in adjacent pixel groups 11 may be the same or different.

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

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

As shown in fig. 1 to 4, for a color image, a plurality of most basic colors, for example, three basic colors of red (R), green (G), and blue (B) are required to be acquired, and thus, corresponding thereto, pixels capable of acquiring respective three colors of R, G, B, that is, a red pixel 111, a green pixel 112, and a blue pixel 113, are required to be provided in the pixel unit 1.

Since the human eye is relatively sensitive to green, the number of green pixels 112 provided in the pixel unit 1 may be greater than the number of red pixels 111 and blue pixels 113. The number of green pixels 112 may be substantially 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 the red pixels 111, the color pixels in the fourth pixel group 11d disposed opposite to the first pixel group 11a may be the blue pixels 113, and the color pixels in the second pixel group 11b and the third pixel group 11c disposed opposite to each other may be the green pixels 112.

The red pixels 111 in the pixel unit 1 are used for transmitting red light, the green pixels 112 are used for transmitting green light, and the blue pixels 113 are used for transmitting blue light, and in a specific application, light of a corresponding color can be transmitted by providing filters corresponding to the pixel colors. The red filter is used for transmitting red light, the green filter is used for transmitting green light and the blue filter is used for transmitting blue light.

If the pixels of three colors R, G, B are respectively corresponded by separately providing the red filter, the green filter and the blue filter, a plurality of filters are required, which is costly and inconvenient to manufacture. To solve this problem, as shown with reference to fig. 1 to 4, the pixel array may be provided as a Bayer color filter array (Bayer Color Filter Array, simply referred to as Bayer array).

The Bayer array is formed by arranging different colors, such as R, G, B colors, on one filter, wherein the three colors respectively correspond to color pixels of corresponding colors, so that the manufacturing efficiency of the pixel array can be improved, the manufacturing cost can be reduced, and the different color parts of the filter can be well aligned to the pixels of corresponding colors.

Referring to fig. 5 to 8c, the pixel array of the present embodiment may be improved by modifying the Bayer array to increase the light incoming amount of the pixel array, so as to further improve the photographing performance of the image sensor in a low-light environment, and improve the imaging quality of the image sensor.

Specifically, in the pixel array of the present embodiment, by providing white (visible light in the full wavelength band is transmitted) in the filter in the Bayer array, the white portion corresponds to the white pixel 114, i.e., at least one of the three colors of R, G, B originally in the Bayer array is replaced with white (W).

It should be noted that, after replacing other color pixels with the white pixel 114, the layout form of the green pixel 112, which is approximately the sum of the red pixel 111 and the blue pixel 113, may be still maintained, so as to meet the requirement of the human eye on the sensitivity of different colors.

In order to improve uniformity of light entering the pixel array while increasing the amount of light entering the pixel array, in one possible embodiment, the white pixels 114 may be uniformly disposed in the plurality of pixel units 1. In the whole pixel array formed by the pixel units 1, the white pixels 114 can be uniformly distributed at intervals in the pixel array, so that the whole pixel array is uniform in light entering, the imaging uniformity of the image sensor can be improved, and the imaging quality of the image sensor can be improved.

Referring to fig. 1, fig. 1 shows a classical Bayer array layout structure, in which R, G, B is the basic color, and a pixel unit 1 is formed by a red pixel 111, a blue pixel 113, and two green pixels 112.

In each pixel unit 1 of the pixel array provided in the present embodiment, as shown in fig. 5, corresponding to the classical Bayer array shown in fig. 1, each pixel group 11 of the pixel unit 1 includes only one pixel, and the pixel unit 1 is composed of four pixels arranged in an array. Of the four pixels constituting the pixel unit 1, at least one pixel is a white pixel 114.

For example, for each pixel unit 1, the pixel unit 1 may have various layout forms, for example, the pixel unit 1 may be formed of four pixels of R, G, B, W, or R, G and two W, or R, B and two W, or G, B and two W, or R, G, B, or any one of the pixels and three W, or the like; here, the position of the white pixel 114 in the pixel unit 1 is not particularly limited.

In order to improve the resolution, photosensitivity, and other performances of the pixel array and reduce the noise of the pixel array, a Bayer array layout, in which pixels of each color are formed by combining and arranging a plurality of pixel groups 11 in each color, i.e., a pixel array, has been developed on the basis of a classical Bayer array, as shown in fig. 2 to 4. Thus, the pixel array with high resolution can be formed, and the pixel array has the performances of dark state high sensitivity and low noise.

For example, as shown in fig. 2, in the pixel array, each color area is formed by combining 4 pixel array arrangements; as shown in fig. 3, each color area is formed by 9 pixel array arrangements; as shown in fig. 4, each color area is formed by combining 16 pixel array arrangements. It will be appreciated that each color region may be further formed by more pixel arrays, which is not limited in this embodiment.

Referring to fig. 6a to 8c, in the pixel array of the present embodiment, a plurality of pixels arranged in a matrix may be included in each pixel group 11 constituting each pixel unit 1 in the present embodiment, corresponding to the layout form of the Bayer array shown in fig. 2 to 4, and at least one white pixel 114 is included in the plurality of pixels in each pixel group 11 to increase the light intake amount of each pixel unit 1 by providing the white pixel 114.

Referring to fig. 6a to 6d, in one embodiment, each pixel group 11 may include four pixels, and the four pixels are arranged in two rows and two columns. I.e. four pixels are combined into one pixel group 11, wherein at least one white pixel 114 is comprised in the four pixels of each pixel group 11.

For example, 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, and in order to improve the uniformity of the distribution of the white pixels 114, taking the paper direction shown in fig. 6a as an example, the white pixels 114 may be located at corners of each pixel group 11 in the same direction, for example, at 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. 6b, each pixel group 11 may include two white pixels 114, and the two white pixels 114 are diagonally offset. 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; alternatively, two white pixels 114 may be located at the upper right and lower left corners of each pixel group 11, respectively. 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 of four pixels forming one pixel group 11, four pixels in one pixel group 11 may be white pixels 114, and four white pixels 114 are adjacently disposed, which 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 therein, and the white pixels 114 in the four pixel groups 11 are adjacently disposed. Taking one pixel group 11 as an example, the white pixels 114 are located at corners of the pixel group 11 adjacent to other pixel groups 11, so that the four white pixels 114 are equivalent to forming a four-in-one white pixel group.

As shown in the layout of the pixel units 1 in fig. 6c and 6d, the number of white pixels 114 in one pixel unit 1 is 25% of the total number of pixels.

Referring to fig. 7a to 7c, in a specific embodiment, each pixel group 11 may include nine pixels, and the nine pixels are arranged in three rows and three columns. I.e. by nine pixels into one pixel group 11, wherein nine pixels in each pixel group 11 comprise at least one white pixel 114.

As shown in fig. 7a, each pixel group 11 includes one white pixel 114, and the white pixels 114 are located at corners of the pixel groups 11, and the white pixels 114 corresponding to the adjacent pixel groups 11 are disposed adjacently. Such four white pixels 114 may correspond 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. 7b, each pixel group 11 includes two white pixels 114, the two white pixels 114 are respectively disposed at two opposite corners of the pixel group 11, and the white pixels 114 corresponding to the adjacent four pixel groups 11 are disposed adjacently, and the adjacent four pixel groups 11 are disposed at the corners of the adjacent four pixel groups 11 and correspond to the four-in-one white pixel groups. 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 adjacent to each other. For example, each pixel group 11 includes four adjacent white pixels 114, and illustratively, the four white pixels 114 in each pixel group 11 are located in the lower right corner in the paper direction in fig. 7 c. In such a pixel unit 1, the number of white pixels 114 is 4/9 of the total number of pixels.

Referring to fig. 8a to 8c, in one embodiment, each pixel group 11 may include sixteen pixels, and sixteen pixels are arranged in four rows and four columns. I.e. by sixteen pixels into one pixel group 11, wherein sixteen pixels in each pixel group 11 comprise at least one white pixel 114.

As shown in fig. 8a, the middle part of each pixel group 11 includes four adjacent white pixels 114, and the number of the white pixels 114 in one pixel unit 1 is 1/4 of the total number of pixels; as shown in fig. 8b, each of four corners of each pixel group 11 is provided with one white pixel 114, and opposite corners of adjacent four pixel groups 11 form four adjacent white pixels 114, wherein in 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 part of each pixel group 11 includes four adjacent white pixels 114, and four adjacent white pixels 114 are formed between the adjacent pixel groups 11, and in one pixel unit 1, the number of white pixels 114 is 4/9 of the total number of pixels.

It should be understood that, as shown in fig. 5 to 8c, only the achievable partial arrangement of the pixel units 1 of the pixel array of the present embodiment is exemplarily illustrated, and the pixel units 1 of the present embodiment include, but are not limited to, the above-described arrangement.

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

In the present embodiment, by providing the white pixel 114 in each pixel unit 1, the amount of light input to each pixel unit 1 is increased, and the amount of light input to the pixel array is further increased. For example, by providing 25% of the white pixels 114 in the pixel unit 1, the light incoming amount of the entire image sensor will be raised by about 30%; by providing 50% of the white pixels 114 in the pixel unit 1, the amount of light entering the entire image sensor will be raised by about 60%.

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

As described above, in the present embodiment, the pixel array may employ the integral filter layer 2 similar to the Bayer array, and the filter layer 2 has the filter portions of different colors distributed thereon, and the filter portions on the filter layer 2 include the red filter portion 21, the green filter portion 22, the blue filter portion 23, and the white filter portion 24 corresponding to the red pixel 111, the green pixel 112, the blue pixel 113, and the white pixel 114. The red filter 21 is used for transmitting red light, the green filter 22 is used for transmitting green light, the blue filter 23 is used for transmitting blue light, and the white filter 24 is used for transmitting full-band visible light.

As shown in fig. 9a and 9b, in one possible embodiment, the pixel array may further include a microlens group 3, the microlens group 3 being disposed on the photosensitive side of the filter layer 2. By arranging the micro-lens group 3 on the photosensitive side of the filter layer 2, light entering the pixel array enters the filter layer 2 after passing through the micro-lens group 3. Therefore, before the incident light passes through the filter layer 2, the light is converged by the micro lens group 3, so that the light entering quantity of the pixel array can be increased, the light brightness is increased, the utilization rate of the array substrate on the incident light is further improved, and a color image with higher quality is output.

The microlens refers to a lens having a minute size, and generally refers to a lens having 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 microlens group 3 may specifically include a plurality of first lenses 31 and a plurality of second lenses 32, where each first lens 31 covers each red pixel 111, each green pixel 112, each blue pixel 113, and each white pixel 114 disposed at intervals, and each second lens 32 covers four white pixels 114 adjacent to each other.

As shown in fig. 9a, for the red pixel 111, the green pixel 112, and the blue pixel 113 in the pixel group 11, the first lens 31 is used to cover the filter portion of the corresponding color in the present embodiment, and each of the above pixels is covered with 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 disposed at intervals, that is, each of the white pixels 114 that are not adjacent to each other, the first lens 31 is also covered on the white filter portion 24 corresponding to such white pixel 114, that is, the first lens 31 covers the white pixels 114 disposed individually.

As shown in fig. 9b, for four white pixels 114 adjacent to each other, which are present in the pixel unit 1 as shown in fig. 6c to 8c, the four white pixels 114 may be covered by the second lens 32, that is, the entire four white pixels 114 may be covered by one second lens 32.

With the four white pixels 114 covered by the second lens 32, since the second lens 32 completely covers the central portions of the four white pixels 114, there are no uncovered areas at the opposite corners of the four white pixels 114, and thus the converging light of the second lens 32 functions better. By providing four white pixels 114 adjacent to each other and correspondingly providing the second lens 32 to entirely cover the four white pixels 114, the amount of light entering can be further increased by about 10%.

It should be understood that the present embodiment is not limited to setting four adjacent white pixels 114, but may also set layout structures such as nine adjacent white pixels 114 in three rows and three columns or sixteen adjacent white pixels 114 in four rows and four columns, and the light incoming amount of the pixel array is further increased by setting lenses with a size matched with the whole area of the adjacent white pixels 114, which is not described herein.

As shown in fig. 9a and 9b, in the present 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; a photodiode 41 is provided for each pixel in the semiconductor substrate 4.

The semiconductor substrate 4 serves as a basic carrier structure for the pixel array, the remaining components of which are arranged on the semiconductor substrate 4. The semiconductor substrate 4 is provided with a photodiode 41, each pixel of the photodiode 41 is provided corresponding to the photodiode 41, the photodiode 41 can generate an output current after receiving light irradiation, the intensity of the current corresponds to the intensity of the light irradiation, and an electric signal is output through the photodiode 41.

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 hold the gate capacitance of the photodiode 41, and the dielectric layer 5 also has a noise reduction effect.

In addition, since each pixel is configured to transmit light corresponding to its color, and adjacent pixels may have different colors to transmit light of different colors, for example, two adjacent pixels are a red pixel 111 and a blue pixel 113, the red pixel 111 is configured to transmit red light, and the blue pixel 113 is configured to transmit blue light. In order to prevent light leakage between adjacent pixels, as shown in fig. 9a and 9b, in one possible embodiment, a spacer 6 may be provided between adjacent pixels.

Through setting up isolation part 6 between adjacent pixel, isolation part 6 can prevent that the light that gets into in the certain pixel from leaking to adjacent pixel, can guarantee like this that each pixel has better filtering capability, and then improves image sensor's formation of image quality. Illustratively, the spacers 6 may be made of a semiconductor material, and the spacers 6 may be disposed within the filter layer 2 and the semiconductor substrate 4 between adjacent pixels; the material of the isolation portion 6 in the filter layer 2 and the material of the isolation portion 6 in the semiconductor substrate 4 may be the same or different.

Fig. 10 is a plan layout view of a pixel array according to an embodiment of the present disclosure. As shown in fig. 10, in the present embodiment, the pixel array may include an effective pixel area a and a photosensitive-free area B located at the periphery of the effective pixel area a, and the plurality of pixel units 1 uniformly cover the effective pixel area a.

The pixel array comprises an effective pixel area A and a non-photosensitive area B, wherein the effective pixel area A is an area capable of sensing light and displaying a color image, and the non-photosensitive area B enables the area surrounding the periphery of the effective pixel area A to be located in the edge area of the pixel array, and the non-photosensitive area B is an area incapable of sensing light and displaying an image. In this embodiment, each pixel unit 1 is uniformly distributed in the effective pixel area a, and is distributed over the entire effective pixel area a.

In the pixel array of the image sensor provided by the embodiment, at least one white pixel is arranged in a plurality of pixels arranged in an array in each pixel unit through the plurality of pixel units arranged in an array on the light sensitive surface of the pixel array, and the white pixel can transmit full-band visible light, so that the light incoming quantity of the pixel array can be increased through the arrangement of the white pixel, particularly, the light incoming quantity of the image sensor in a low illumination environment has a remarkable enhancement effect, and the focusing performance of the pixel array can be improved while the light incoming quantity of the pixel array is increased through the arrangement of the white pixel, so that the photographing performance of the image sensor in the low illumination environment can be improved, and the imaging quality of the sensor is improved.

Example two

Fig. 11 is a schematic diagram of an image sensor according to a second embodiment of the present application. As shown in fig. 11, the present embodiment provides an image sensor 100, which includes a readout circuit 120, an image processor 130, an output interface 140, and a pixel array 110 according to the first embodiment, where the pixel array 110, the readout circuit 120, the image processor 130, and the output interface 140 are electrically connected in sequence; the readout circuit 120 is configured to convert an analog signal collected by the pixel array 110 into a digital signal, the image processor 130 is configured to process the digital signal, and the output interface 140 is configured to output the processed digital signal.

In the image sensor 100 of the present embodiment, firstly, the pixel array 110 receives the light collecting signal, specifically, the photodiode in the pixel array 110 senses light to generate a current output signal, and the electrical signal output by the photodiode is usually an analog signal, then the analog signal is converted into a corresponding digital signal by the readout circuit 120, and then the digital signal is processed by the image processor 130, for example, the image processor 130 performs the processing of linear correction, noise removal, dead point removal, interpolation, white balance, automatic exposure, and the like; the digital signal is processed by the image processor 130 and then 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 image sensor 100 is controlled by the system control unit 150, and parameters such as an operating voltage and an operating current of the image sensor 100 are controlled by the power management unit 160.

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

In the present 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 12b, in one possible embodiment, the processing mode of the digital signal by the image processor 130 may include a full resolution mode for separately outputting each pixel signal in each pixel unit and a high sensitivity mode for combining and outputting the pixel signals of the same color in each pixel unit.

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, the pixel unit is restored to a classical Bayer array having R, G, B pixels and a white pixel array 110 having the same resolution by individually outputting each pixel signal in each pixel unit, and the data of the RGB pixels is processed by the back-end main control image processing unit.

The full resolution mode can obtain an image signal with higher resolution by separately processing each pixel signal within a pixel unit.

As shown in fig. 12b, taking the pixel unit shown in fig. 6a as an example, for the high sensitivity mode of the image processor 130, by combining all pixels with the same color in the pixel unit and outputting the combined pixels, for example, combining three red pixels and three blue pixels and outputting the combined pixels, combining the green pixels in the two pixel groups respectively and outputting the combined pixels to form a Bayer array with R, G, B pixels, combining the 4 white pixels and outputting a white pixel array 110 with the same resolution, and processing the data of the RGB pixels by the master image processing unit at the rear end.

The high sensitivity mode can obtain an image signal having a strong light sensing capability by combining and outputting pixels of the same color.

It should be understood that, for the nine-in-one pixel units shown in fig. 7a to 7c and the sixteen-in-one pixel units shown in fig. 8a to 8c, other layout forms of pixel units are also suitable for performing data processing in the full resolution mode or the high sensitivity mode of the image processor 130, which is not described herein.

Example III

Further, on the basis of the foregoing embodiment, the present embodiment provides an electronic device including the image sensor described in the second embodiment.

In this embodiment, the electronic device may be a smart phone, a camera, a tablet pc, or other mobile devices with imaging functions.

According to the embodiment, the pixel array in the image sensor of the electronic device is designed, at least one white pixel is arranged in a plurality of pixels arranged in an array in each pixel unit of the pixel array, and the white pixel can transmit full-band visible light, so that the light inlet quantity of the pixel array can be increased through the arrangement of the white pixel, particularly, the light inlet quantity of the image sensor in a low-light environment has a remarkable enhancement effect, the light inlet quantity of the pixel array is increased through the arrangement of the white pixel, the focusing performance of the pixel array can be improved, and further the photographing performance of the image sensor in the low-light environment can be improved, and the imaging quality of the sensor is improved.

Finally, it should be noted that: the above embodiments are only for illustrating the technical solution of the present application, and not for limiting the same; although the present application has been described in detail with reference to the foregoing embodiments, it should be understood by those of ordinary skill in the art that: the technical scheme described in the foregoing embodiments can be modified or some or all of the technical features thereof can be replaced by equivalents; such modifications and substitutions do not depart from the spirit of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present application.

Claims

1. The pixel array of the image sensor is characterized by comprising a plurality of pixel units which are arranged in an array manner on a light sensitive surface, wherein a plurality of pixels are arranged in each pixel unit in the array manner, each pixel comprises a plurality of color pixels and at least one white pixel, each color pixel is used for transmitting light wave bands corresponding to own colors, and each white pixel is used for transmitting visible light of all wave bands;

each pixel unit comprises a plurality of pixel groups which are arranged in an array way, wherein the plurality of pixel groups comprise a first pixel group and a second pixel group which are adjacent in the row direction, and a third pixel group and a fourth pixel group which are positioned in adjacent rows and are respectively adjacent to the first pixel group and the second pixel group in the column direction;

wherein at least one of the first, second, third, and fourth pixel groups has the white pixel;

the white pixels are uniformly arranged at intervals in the pixel units;

each pixel group comprises a plurality of pixels which are arranged in a matrix, and each pixel group at least comprises one white pixel;

the rows and columns of each pixel group are equal;

Each pixel group comprises four pixels, nine pixels or sixteen pixels;

each pixel group comprises two white pixels, and the two white pixels are diagonally staggered; or,

the white pixels are positioned at the corners of the pixel groups, and the white pixels corresponding to the adjacent pixel groups are arranged adjacently; or,

at least one pixel group comprises four adjacent white pixels;

the pixel array comprises a filter layer and a micro lens group, wherein the micro lens group is arranged on the photosensitive side of the filter layer;

the micro lens group comprises a plurality of second lenses, and each second lens covers four adjacent white pixels.

2. The pixel array of the image sensor of claim 1, wherein the color pixels of each of the pixel groups other than the white pixel are the same color, and the color pixels of the second pixel group and the third pixel group are the same, and the color pixels of the first pixel group and the fourth pixel group are different in color and different from the second pixel group and the third pixel group.

3. The pixel array of the image sensor of claim 2, wherein 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.

4. The pixel array of claim 3, wherein the filter layer includes a red filter, a green filter, a blue filter, and a white filter disposed corresponding to the red pixel, the green pixel, the blue pixel, and the white pixel, respectively.

5. The pixel array of claim 3, wherein the microlens assembly further comprises a plurality of first lenses, each of the first lenses covering each of the red pixels, green pixels, blue pixels, and each of the white pixels disposed at intervals.

6. The pixel array of claim 5, further comprising a semiconductor substrate and a dielectric layer disposed on the semiconductor substrate, the filter layer and the microlens set being sequentially stacked on the dielectric layer.

7. The pixel array of claim 6, wherein a photodiode is disposed in the semiconductor substrate for each pixel.

8. The pixel array of an image sensor according to any one of claims 4 to 7, wherein a spacer is provided between adjacent pixels, the spacer being for preventing light leakage between adjacent pixels.

9. A pixel array of an image sensor according to any one of claims 1-3, 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 the effective pixel area.

10. An image sensor, comprising a readout circuit, an image processor, an output interface, and the pixel array of the image sensor of any one of claims 1-9, wherein the pixel array, the readout circuit, the image processor, and the output interface are electrically connected in sequence;

the readout circuit is used for converting the analog signals acquired by the pixel array into digital signals, the image processor is used for processing the digital signals, and the output interface is used for outputting the processed digital signals.

11. The image sensor of claim 10, wherein the image processor is configured to output the digital signal of each pixel cell of the pixel array as a color pixel signal and a white pixel signal;

the image processor outputs the digital signals in a processing mode including a full resolution mode and a high sensitivity mode, wherein the full resolution mode is used for outputting each pixel signal in each pixel unit independently, and the high sensitivity mode is used for outputting the pixel signals with the same color in each pixel unit after combining.

12. An electronic device comprising the image sensor of claim 10 or 11.