WO2021136469A1 - 一种图像传感器、分光滤色器件及图像传感器的制备方法 - Google Patents

一种图像传感器、分光滤色器件及图像传感器的制备方法 Download PDF

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Publication number
WO2021136469A1
WO2021136469A1 PCT/CN2020/141893 CN2020141893W WO2021136469A1 WO 2021136469 A1 WO2021136469 A1 WO 2021136469A1 CN 2020141893 W CN2020141893 W CN 2020141893W WO 2021136469 A1 WO2021136469 A1 WO 2021136469A1
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Prior art keywords
color
array
photoelectric conversion
light
metasurface
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PCT/CN2020/141893
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English (en)
French (fr)
Inventor
张友明
孙上
刘闯闯
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华为技术有限公司
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Priority claimed from PCT/CN2019/130438 external-priority patent/WO2021134450A1/zh
Priority claimed from PCT/CN2020/130020 external-priority patent/WO2022104629A1/zh
Application filed by 华为技术有限公司 filed Critical 华为技术有限公司
Priority to EP20911103.8A priority Critical patent/EP4071819A4/en
Priority to KR1020227024326A priority patent/KR102688871B1/ko
Priority to JP2022540556A priority patent/JP2023509034A/ja
Priority to CN202080088569.1A priority patent/CN114830341A/zh
Publication of WO2021136469A1 publication Critical patent/WO2021136469A1/zh
Priority to US17/854,962 priority patent/US20220336509A1/en

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L27/00—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate
    • H01L27/14—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate including semiconductor components sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation
    • H01L27/144—Devices controlled by radiation
    • H01L27/146—Imager structures
    • H01L27/14643—Photodiode arrays; MOS imagers
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L27/00—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate
    • H01L27/14—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate including semiconductor components sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation
    • H01L27/144—Devices controlled by radiation
    • H01L27/146—Imager structures
    • H01L27/14601—Structural or functional details thereof
    • H01L27/1462—Coatings
    • H01L27/14621—Colour filter arrangements
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L27/00—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate
    • H01L27/14—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate including semiconductor components sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation
    • H01L27/144—Devices controlled by radiation
    • H01L27/146—Imager structures
    • H01L27/14601—Structural or functional details thereof
    • H01L27/14625—Optical elements or arrangements associated with the device
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L27/00—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate
    • H01L27/14—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate including semiconductor components sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation
    • H01L27/144—Devices controlled by radiation
    • H01L27/146—Imager structures
    • H01L27/14601—Structural or functional details thereof
    • H01L27/14625—Optical elements or arrangements associated with the device
    • H01L27/14627—Microlenses
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L27/00—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate
    • H01L27/14—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate including semiconductor components sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation
    • H01L27/144—Devices controlled by radiation
    • H01L27/146—Imager structures
    • H01L27/14643—Photodiode arrays; MOS imagers
    • H01L27/14645—Colour imagers
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L27/00—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate
    • H01L27/14—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate including semiconductor components sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation
    • H01L27/144—Devices controlled by radiation
    • H01L27/146—Imager structures
    • H01L27/14643—Photodiode arrays; MOS imagers
    • H01L27/14649—Infrared imagers
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L27/00—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate
    • H01L27/14—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate including semiconductor components sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation
    • H01L27/144—Devices controlled by radiation
    • H01L27/146—Imager structures
    • H01L27/14683—Processes or apparatus peculiar to the manufacture or treatment of these devices or parts thereof
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L27/00—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate
    • H01L27/14—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate including semiconductor components sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation
    • H01L27/144—Devices controlled by radiation
    • H01L27/146—Imager structures
    • H01L27/14683—Processes or apparatus peculiar to the manufacture or treatment of these devices or parts thereof
    • H01L27/14685—Process for coatings or optical elements

Definitions

  • This application relates to the imaging field, and in particular to an image sensor, a spectroscopic color filter device, and a manufacturing method of the image sensor.
  • Image sensors can convert optical images into electrical signals, and are widely used in a variety of electronic devices, such as digital cameras.
  • the hardware of a digital camera mainly includes a lens group, an image sensor, and an electrical signal processor.
  • the lens group is used to image an optical image on the image sensor.
  • the image sensor is used to convert the light signal of the image into an analog electrical signal and input it to the electrical signal.
  • the electrical signal processor converts analog electrical signals into digital signals, and after data processing, outputs photos.
  • the image sensor is one of the core components of a digital camera, and its performance directly determines the quality of the output photo.
  • the photoelectric conversion element of the image sensor can convert light signals of different intensities into electrical signals of different intensities.
  • the photoelectric conversion element itself cannot distinguish the frequency of light, that is, it cannot distinguish the color. Therefore, the pictures directly obtained by using an image sensor that does not contain a color acquisition layer are black and white.
  • a color filter system is required as a color collection layer to obtain the color information of the picture.
  • the human eye is sensitive to the spectrum of the three primary colors of red, green and blue (RGB), and the RGB color filter is arranged on the photoelectric conversion element to form an RGB mosaic Bayer color filter system, which can obtain color image.
  • RGB red, green and blue
  • the RGB color filter is arranged on the photoelectric conversion element to form an RGB mosaic Bayer color filter system, which can obtain color image.
  • the utilization rate of light is relatively low.
  • the total light utilization rate for incident white light is only about 25%; for the incident red light or blue light, the utilization rate is only about 15%.
  • the light utilization rate of incident green light is about 30%, etc. Therefore, how to improve the light utilization rate has become an urgent problem to be solved.
  • the embodiments of the present application provide an image sensor, a light-splitting color filter device, and a manufacturing method of the image sensor, which are used to improve the utilization rate of light incident on the image sensor.
  • the first aspect of the present application provides an image sensor that includes: a metasurface, a substrate, and a photoelectric conversion unit; the metasurface includes a plurality of subunits, and each subunit includes an array formed by a plurality of columnar structures.
  • the array is arranged on the top of the substrate, and the bottom of the substrate is set on the surface (or called the top) of the photoelectric conversion unit.
  • the metasurface includes at least two media with different refractive indices.
  • the photoelectric conversion unit includes an array for photoelectric conversion, The array of photoelectric conversion units is divided into a plurality of color regions, and the metasurface is used to refract and transmit incident light to the corresponding color regions in the array of photoelectric conversion units through the substrate.
  • the array of photoelectric conversion units can be divided into multiple color units, each color unit includes at least four color areas, each color unit corresponds to a subunit, and each subunit refracts incident light and transmits it to the corresponding color unit. In the color area.
  • the incident light can be refracted through an array formed by at least two media with different refractive indexes on the metasurface, so that light of different frequency bands can be refracted to the corresponding color regions in the photoelectric conversion unit.
  • Improved light utilization compared with the Bayer color filter, the super-surface of the image sensor provided in the present application can refract light of multiple different frequency bands to the corresponding color area, avoiding the problem of low light utilization due to filtering. It can be understood that the metasurface can diffract the incident light, so that the light of different frequency bands can be transmitted to the corresponding color area in the photoelectric conversion unit, and the light utilization rate can be improved.
  • a color filter structure is further provided between the photoelectric conversion unit and the substrate.
  • the color filter structure is divided into a plurality of color filter regions, and each color filter region covers a corresponding color region, and each The color corresponding to each color area is the same as the color transmitted by the color filter area covered by each color area.
  • a color filter structure may be further provided between the photoelectric conversion unit and the substrate to filter signals different from light in the frequency band corresponding to the color region, and reduce crosstalk.
  • a lens is further provided between each color filter area and the substrate.
  • a lens may be further provided between each color filter area and the substrate to converge the light incident on the color filter area.
  • the light of multiple frequency bands corresponding to the multiple color regions includes one or more of green, red, blue, or infrared light. Therefore, in the embodiments of the present application, the photoelectric conversion unit can convert optical signals in multiple frequency bands into electrical signals, so that images with more color channels can be subsequently generated.
  • the material of the supersurface includes one or more of the following: titanium dioxide, gallium nitride, or silicon carbide.
  • the color corresponding to each color unit includes at least two identical colors, and the columnar structure included in the region corresponding to each color unit in the metasurface forms an angularly symmetrical shape.
  • every four color regions arranged in a matrix can correspond to at least two of the same colors, and the colors corresponding to the two symmetrical color regions may be the same.
  • This embodiment provides a possible arrangement of arrays suitable for metasurfaces. .
  • the present application provides a spectroscopic color filter device, including: a metasurface and a substrate;
  • the metasurface includes a plurality of subunits, and each subunit includes an array composed of a plurality of columnar structures.
  • the array in the metasurface is arranged on the top of the substrate.
  • the metasurface includes at least two media with different refractive indexes. The light is refracted, and the substrate is used to transmit the light refracted by the metasurface.
  • the incident light can be refracted by an array formed by at least two media with different refractive indexes on the metasurface, so that light of different frequency bands can be refracted to different regions, which improves the light utilization efficiency.
  • the super-surface of the spectroscopic color filter provided in the present application can refract light of multiple different frequency bands to the corresponding color area, avoiding the problem of low light utilization due to filtering.
  • the spectroscopic filter device can be applied to an image sensor, the image sensor includes a photoelectric conversion unit, the substrate is arranged on the surface of the photoelectric conversion unit, the photoelectric conversion unit includes an array for photoelectric conversion, photoelectric conversion unit The array of conversion units is divided into a plurality of color regions, and the metasurface refracts incident light and transmits it through the substrate to the corresponding color regions in the array of photoelectric conversion units. It can be understood that the metasurface can diffract the incident light, so that the light of different frequency bands can be transmitted to the corresponding color area in the photoelectric conversion unit, and the light utilization rate can be improved.
  • the array of photoelectric conversion units can be divided into multiple color units, each color unit includes at least four color areas, each color unit corresponds to a subunit in the metasurface, and each subunit refracts incident light and transmits it to The corresponding color cell in the color area.
  • a color filter structure is further provided between the photoelectric conversion unit and the substrate.
  • the color filter structure is divided into a plurality of color filter regions, and each color filter region covers a corresponding color region, and each color filter region covers a corresponding color region.
  • the color corresponding to each color area is the same as the color transmitted by the color filter area covered by each color area.
  • a color filter structure may be further provided between the photoelectric conversion unit and the substrate to filter signals different from light in the frequency band corresponding to the color region, and reduce crosstalk.
  • a lens is further provided between each color filter area and the substrate.
  • a lens may be further provided between each color filter area and the substrate to converge the light incident on the color filter area.
  • light of multiple frequency bands of colors corresponding to multiple color regions includes one or more of green, red, blue, or infrared light. Therefore, in the embodiments of the present application, the photoelectric conversion unit can convert optical signals in multiple frequency bands into electrical signals, so that images with more color channels can be subsequently generated.
  • the material of the supersurface includes one or more of the following: titanium dioxide, gallium nitride, or silicon carbide.
  • the color corresponding to each color unit includes at least two identical colors, and the columnar structure included in the region corresponding to each color unit in the metasurface forms an angularly symmetrical shape.
  • this application provides a method for manufacturing an image sensor, including:
  • the photoelectric conversion unit is used to convert an optical signal into an electrical signal, the photoelectric conversion unit includes an array for photoelectric conversion, and the array of the photoelectric conversion unit is divided into a plurality of color regions;
  • a spectroscopic filter device is prepared on the surface of the photoelectric conversion unit.
  • the spectroscopic filter device includes a metasurface and a substrate.
  • the metasurface includes a plurality of subunits. Each subunit includes an array formed by a columnar structure. The arrays in the metasurface are arranged on the substrate.
  • the top of the photoelectric conversion unit, the bottom of the substrate is set on the surface of the photoelectric conversion unit, the metasurface includes at least two media with different refractive indices, the photoelectric conversion unit includes an array for photoelectric conversion, and the surface of the photoelectric conversion unit is the surface that receives light signals,
  • the array of photoelectric conversion units is divided into a plurality of color regions, and the metasurface is used to refract incident light to the corresponding color regions in the array of photoelectric conversion units.
  • the array of photoelectric conversion units can be divided into multiple color units, each color unit includes at least four color areas, each color unit corresponds to a subunit in the metasurface, and each subunit refracts incident light and transmits it to The corresponding color cell in the color area. Therefore, in the embodiment of the present application, the prepared image sensor has an array formed by at least two media with different refractive indexes on the metasurface of the spectroscopic filter device, which refracts incident light so that light of different frequency bands can be refracted to The corresponding color area in the photoelectric conversion unit improves the light utilization rate. Moreover, compared with the Bayer color filter, the super-surface of the spectroscopic color filter provided in the present application can refract light of multiple different frequency bands to the corresponding color area, avoiding the problem of low light utilization due to filtering.
  • the method before preparing the spectroscopic filter device on the surface of the photoelectric conversion unit, the method further includes: determining a plurality of arrays, and using the plurality of arrays as the supersurface structure of the spectroscopic filter device to obtain multiple Spectroscopic structure; multiple evaluation values corresponding to multiple spectroscopic structures are obtained through a preset evaluation function.
  • the evaluation function is a function for calculating the light utilization rate of the spectroscopic structure; if the multiple evaluation values include those higher than the preset value At least one evaluation value, the first spectroscopic structure is selected from the multiple spectroscopic structures as the structure of the spectroscopic filter device, and the evaluation value of the first spectroscopic structure is higher than the preset value.
  • the light utilization efficiency of each array can be calculated through the simulation model established in advance, so as to obtain the array with the light utilization efficiency exceeding the preset value, and then to prepare the image sensor with the light utilization efficiency exceeding the preset value.
  • optimization algorithms such as genetic algorithms, simulated annealing algorithms, or gradient descent can be used to reversely obtain an array that meets the light utilization requirements, thereby improving the spectral filter device and The light utilization rate of the image sensor.
  • the method may further include: if the plurality of evaluation values does not include at least one evaluation value higher than the preset value, re-determining multiple arrays, and determining the spectroscopy according to the re-determined multiple arrays
  • the structure serves as the structure of the light splitting filter device.
  • the plurality of arrays can be updated to obtain a new plurality of arrays until the evaluation value is higher than the preset value.
  • the array of values if the plurality of arrays does not include an array with an evaluation value higher than the preset value, the plurality of arrays can be updated to obtain a new plurality of arrays until the evaluation value is higher than the preset value.
  • re-determining the multiple arrays may include: determining the mutation rate corresponding to each of the multiple arrays according to the values of the multiple evaluation values; and determining the mutation rate corresponding to each array according to the mutation rate corresponding to each array.
  • the array is mutated, and multiple updated arrays are obtained.
  • a new array can be obtained through mutation until an array with an evaluation value higher than a preset value is obtained.
  • the variation rate corresponding to each array includes a shape variation rate and/or a height variation rate
  • the shape variation rate includes a probability or a ratio of mutating the shape of each array
  • the height variation rate includes the probability or ratio of the height variation of each array. Therefore, the embodiment of the present application can mutate the array from different dimensions such as shape or height to obtain a variety of different array structures.
  • re-determining multiple arrays may include: determining the probability value corresponding to each array in the multiple arrays according to the values of the multiple evaluation values; Several arrays are sampled multiple times to obtain multiple intermediate structures; the mutation rate of multiple intermediate structures is determined according to the evaluation values of multiple intermediate structures; the multiple intermediate structures are mutated according to the corresponding mutation rates of multiple intermediate structures to obtain new Multiple arrays.
  • the probability value corresponding to each array can be determined according to the evaluation value of each array, and then sampling is performed based on the probability value of each array, so as to screen out the arrays with higher evaluation value, The resulting array is mutated to obtain a new array until an array with an evaluation value higher than the preset value is obtained.
  • the method may further include: preparing a color filter structure between the photoelectric conversion unit and the substrate, the color filter structure is divided into a plurality of color filter regions, and each color filter region covers a corresponding color Area, and the color corresponding to each color area is the same as the color transmitted by the color filter area covered on each color area, and each color filter area is used to filter light of colors other than the colors corresponding to the covered color area.
  • the method may further include: preparing a lens between each color filter area and the substrate.
  • a lens may be further provided between each color filter area and the substrate to converge the light incident on the color filter area.
  • the light of multiple frequency bands corresponding to the multiple color regions includes one or more of green, red, blue, or infrared light. Therefore, in the embodiments of the present application, the photoelectric conversion unit can convert optical signals in multiple frequency bands into electrical signals, so that images with more color channels can be subsequently generated.
  • the material of the supersurface includes one or more of the following: titanium dioxide, gallium nitride, or silicon carbide.
  • the colors corresponding to each color unit include at least two identical colors, and the columnar structure included in the region corresponding to each color unit in the metasurface forms an angularly symmetrical shape.
  • the present application also provides an electronic device, which may include the image sensor in the aforementioned first aspect, or the image sensor prepared by the third aspect.
  • the present application provides a method for determining an array structure applied to an image sensor.
  • the image sensor includes a light splitting filter device and a photoelectric conversion unit.
  • the light splitting filter device includes a supersurface and a substrate.
  • the unit includes an array for photoelectric conversion
  • the spectroscopic filter device includes a metasurface and a substrate
  • the array in the metasurface includes a plurality of subunits
  • each subunit includes an array formed by a plurality of columnar structures
  • the metasurface The array in the photoelectric conversion unit is arranged on the top of the substrate, the bottom of the substrate is arranged on the surface of the photoelectric conversion unit
  • the metasurface includes at least two media with different refractive indexes, and the array of the photoelectric conversion unit is divided into multiple
  • the metasurface is used to refract incident light to the corresponding color area in the array of the photoelectric conversion unit.
  • the method includes: determining the structure of a plurality of arrays; The structure is evaluated, and an evaluation value corresponding to each of the plurality of arrays is obtained.
  • the evaluation function is calculated as the light of the spectroscopic filter device when the plurality of arrays are used as the super-surface of the spectroscopic filter device.
  • a function of the utilization rate; the super-surface structure of the spectroscopic filter device is determined according to the evaluation value.
  • the array of photoelectric conversion units can be divided into multiple color units, each color unit includes at least four color areas, each color unit corresponds to a subunit in the metasurface, and each subunit refracts incident light and transmits it to The corresponding color cell in the color area.
  • the determining the structure of the super-surface array of the spectroscopic filter device according to the evaluation value may include: if the plurality of arrays includes at least one whose evaluation value is higher than a preset value One array is selected from the at least one array whose evaluation value is higher than the preset value, and one of the arrays is selected as the structure of the super-surface array of the spectroscopic filter device; if the plurality of arrays does not include the evaluation value higher than The preset value of the array is updated, and the structure of the super-surface array of the light splitting filter device is determined according to the updated multiple arrays.
  • the updating the multiple arrays may include: determining the mutation rate corresponding to each of the multiple arrays according to the values of the multiple evaluation values; The mutation rate corresponding to each array mutates the multiple arrays to obtain updated multiple arrays.
  • the variation rate corresponding to each array includes a shape variation rate and/or a height variation rate
  • the shape variation rate includes a probability or a ratio of mutating the shape of each array
  • the height variation rate includes the probability or ratio of the height variation of each array.
  • the updating the multiple arrays may include: determining a probability value corresponding to each array in the multiple arrays according to the value of the multiple evaluation values; The probability values corresponding to each array are sampled multiple times to obtain multiple intermediate structures; the mutation rate of the multiple intermediate structures is determined according to the evaluation values of the multiple intermediate structures; and the mutation rate of the multiple intermediate structures is determined according to the evaluation values of the multiple intermediate structures; The mutation rate corresponding to the intermediate structure mutates the plurality of intermediate structures to obtain a plurality of new arrays.
  • the color corresponding to each color unit includes at least two identical colors, and the columnar structure included in the region corresponding to each color unit in the metasurface forms an angularly symmetrical shape.
  • an array structure construction device including:
  • the first determining unit is used to determine the structure of a plurality of arrays
  • the evaluation unit is used to evaluate the structure of the plurality of arrays through an evaluation function to obtain an evaluation value corresponding to each of the plurality of arrays, and the evaluation function is to calculate the plurality of arrays as the spectrometer
  • the super-surface of the color filter device is a function of the light utilization efficiency of the spectroscopic color filter device;
  • the second determining unit is configured to determine the super-surface structure of the color separation filter device according to the evaluation value.
  • the color separation filter device is included in an image sensor.
  • the image sensor includes a color separation filter device and a photoelectric conversion unit.
  • the device includes a supersurface and a substrate.
  • the photoelectric conversion unit includes an array for photoelectric conversion.
  • the spectroscopic filter device includes a supersurface and a substrate. The array in the supersurface is arranged on the top of the substrate, and the bottom of the substrate is set on the photoelectric conversion.
  • the surface of the unit, the metasurface includes an array composed of at least two media with different refractive indices, the array in the metasurface includes a plurality of sub-units, each sub-unit includes an array formed by a plurality of columnar structures, and the array of photoelectric conversion units is divided into multiple Color area, the metasurface is used to refract incident light to the corresponding color area in the photoelectric conversion unit array.
  • the array of photoelectric conversion units can be divided into multiple color units, each color unit includes at least four color areas, each color unit corresponds to a subunit in the metasurface, and each subunit refracts incident light and transmits it to The corresponding color cell in the color area.
  • the first determining unit is specifically configured to, if the plurality of arrays include at least one array whose evaluation value is higher than a preset value, select at least one of the arrays whose evaluation value is higher than the preset value.
  • One of the arrays is selected as the structure of the super-surface array of the light-splitting color filter device;
  • the device for constructing an array structure may further include: an update unit configured to update the plurality of arrays if the arrays with an evaluation value higher than a preset value are not included in the plurality of arrays;
  • the second determining unit is further configured to determine the structure of the super-surface array of the light splitting filter device according to the updated multiple arrays.
  • the update unit is specifically configured to determine the mutation rate corresponding to each of the multiple arrays according to the values of the multiple evaluation values; according to the mutation rate corresponding to each array The multiple arrays are mutated to obtain updated multiple arrays.
  • the update unit is specifically configured to determine the probability value corresponding to each array in the multiple arrays according to the values of the multiple evaluation values; according to the probability value corresponding to each array , Sampling the plurality of arrays multiple times to obtain a plurality of intermediate structures; determining the mutation rate of the plurality of intermediate structures according to the evaluation value of the plurality of intermediate structures; according to the mutation rate corresponding to the plurality of intermediate structures The multiple intermediate structures are mutated to obtain new multiple arrays.
  • the color corresponding to each color unit includes at least two identical colors, and the columnar structure included in the region corresponding to each color unit in the metasurface forms an angularly symmetrical shape.
  • the embodiments of the present application provide an array structure construction device.
  • the array structure construction device may also be called a digital processing chip or a chip.
  • the chip includes a processing unit and a communication interface.
  • the processing unit obtains program instructions through the communication interface.
  • the instructions are executed by the processing unit, and the processing unit is configured to perform processing-related functions as in the foregoing fifth aspect or any optional implementation manner of the fifth aspect.
  • an embodiment of the present application provides a computer-readable storage medium, including instructions, which when run on a computer, cause the computer to execute the method in the fifth aspect or any optional implementation manner of the fifth aspect.
  • the embodiments of the present application provide a computer program product containing instructions that, when run on a computer, cause the computer to execute the method in the fifth aspect or any optional implementation manner of the fifth aspect.
  • FIG. 1 is a schematic structural diagram of an electronic device provided by an embodiment of this application.
  • FIG. 2 is a schematic diagram of the structure of an image sensor provided by this application.
  • FIG. 3 is a structure of a Bayer color filter provided by this application.
  • FIG. 4 is a structure of another Bayer color filter provided by this application.
  • Fig. 5 is a schematic diagram of optical signal transmission of a spectral channel
  • FIG. 6 is a schematic diagram of refraction and reflection of an optical signal provided by this application.
  • FIG. 7 is a schematic diagram of the structure of a color splitting filter device provided by this application.
  • FIG. 8 is a schematic structural diagram of an image sensor provided by this application.
  • FIG. 9A is a schematic structural diagram of another light-splitting color filter device provided by this application.
  • FIG. 9B is a schematic diagram of the structure of a metasurface provided by this application.
  • FIG. 10 is a schematic structural diagram of another image sensor provided by this application.
  • FIG. 11 is a schematic structural diagram of a photoelectric conversion unit provided by this application.
  • FIG. 12 is a schematic structural diagram of another image sensor provided by this application.
  • FIG. 13 is a schematic structural diagram of another image sensor device provided by this application.
  • FIG. 14 is a schematic flowchart of a method for determining an array structure provided by the present application.
  • FIG. 15 is a schematic diagram of the structure of another metasurface provided by this application.
  • FIG. 16 is a schematic flowchart of a method for manufacturing an image sensor provided by the present application.
  • FIG. 17 is a schematic flowchart of a method for manufacturing an image sensor provided by the present application.
  • FIG. 18 is a schematic diagram of a light utilization frequency spectrum of a color separation filter device provided by the present application.
  • 19 is a schematic diagram of light intensity distribution in a photoelectric conversion unit provided by the present application.
  • FIG. 20 is a schematic structural diagram of an array structure construction device provided by the present application.
  • the terms “installed”, “connected”, “connected”, “fixed”, “set” and other terms should be understood in a broad sense.
  • it can be a fixed connection or a fixed connection. It can be detachably connected or integrated; it can be mechanically connected or electrically connected; it can be directly connected or indirectly connected through an intermediate medium, and it can also be the internal communication of two components or the interaction relationship between two components .
  • the specific meanings of the above-mentioned terms in this application can be understood according to specific circumstances.
  • Metamaterial A broad definition refers to a composite of artificially designed unit structures with physical properties that traditional natural materials do not possess. Its physical properties are mainly determined by the structure and arrangement of sub-wavelength (much less than the wavelength) unit structure.
  • Metasurface A two-dimensional form of metamaterials.
  • the metasurface in this application includes.
  • Focus When light enters the metasurface structure, the light converges at several points behind the metasurface structure. These points where the light is converged are the focal points.
  • Focal length also called focal length, it is a measure of the concentration or divergence of light in an optical system. In the embodiments of this application, it refers to the distance from the optical center of the metasurface structure to the focal point when a scene at infinity is formed on the focal plane through the metasurface structure to form a clear image, which can also be understood as the vertical distance from the optical center of the metasurface structure to the focal plane. .
  • the electronic devices provided in the embodiments of the present application may include handheld devices, vehicle-mounted devices, wearable devices, computing devices, or other processing devices connected to a wireless modem. It can also include digital cameras, cellular phones, smart phones, personal digital assistants (PDAs), tablet computers, laptop computers, and machines. Type of communication (machine type communication, MTC) terminals, point of sales (POS), car computers, headsets, wearable devices (such as bracelets, smart watches, etc.), security equipment, virtual reality (virtual reality, VR) ) Devices, augmented reality (AR) devices, and other electronic devices with imaging functions.
  • MTC machine type communication
  • POS point of sales
  • POS point of sales
  • car computers headsets
  • wearable devices such as bracelets, smart watches, etc.
  • security equipment virtual reality (virtual reality, VR) ) Devices, augmented reality (AR) devices, and other electronic devices with imaging functions.
  • VR virtual reality
  • AR augmented reality
  • Digital camera is short for digital camera, which uses photoelectric sensor to convert optical image into digital signal.
  • the sensor of a digital camera is a light-sensitive charge-coupled device (CCD) or complementary metal oxide semiconductor (complementary metal oxide semiconductor). , CMOS).
  • CCD charge-coupled device
  • CMOS complementary metal oxide semiconductor
  • CMOS complementary metal oxide semiconductor
  • CMOS processing technology the functions of digital cameras have become more and more powerful, and they have almost completely replaced traditional film cameras. They have been widely used in consumer electronics, security, human-computer interaction, computer vision, autonomous driving and other fields.
  • FIG. 1 shows a schematic diagram of an electronic device provided by the present application.
  • the electronic device may include a lens group 110, an image sensor (sensor) 120, and an electrical signal processor 130.
  • the electrical signal processor 130 may include an analog-to-digital (A/D) converter 131 and a digital signal processor 132.
  • the analog-to-digital converter 131 is an analog signal-to-digital signal converter for converting analog electrical signals into digital electrical signals.
  • the electronic device shown in FIG. 1 is not limited to include the above devices, and may also include more or less other devices, such as batteries, flashlights, buttons, sensors, etc.
  • the embodiment of the present application only uses image sensors.
  • the electronic device of 120 is described as an example, but the components installed on the electronic device are not limited to this.
  • the light signal reflected by the subject is converged by the lens group 110 and is imaged on the image sensor 120.
  • the image sensor 120 converts the optical signal into an analog electric signal.
  • the analog electrical signal is converted into a digital electrical signal by the analog-to-digital (A/D) converter 131 in the electrical signal processor 130, and the digital electrical signal is processed by the digital signal processor 132, for example, through a series of complex mathematical algorithms. , Optimize the data electrical signal, and finally output the image.
  • the electrical signal processor 130 may further include an analog signal pre-processor 133 for preprocessing the analog electrical signal transmitted by the image sensor and output to the analog-to-digital converter 131.
  • the performance of the image sensor 120 affects the quality of the final output image.
  • the image sensor 120 may also be referred to as a photosensitive chip, a photosensitive element, etc., and contains hundreds of thousands to millions of photoelectric conversion elements. When irradiated by light, charges are generated and converted into digital signals by an analog-to-digital converter chip.
  • the image sensor 120 can obtain color information of an image through a color filter system.
  • the color filter system may be a Bayer color filter system. That is, the Bayer color filter is covered above the photoelectric conversion element in the image sensor 120 to form a color filter system.
  • the photoelectric conversion element may be a photodiode.
  • Bayer color filters can also be called Bayer filters.
  • Figure 2 shows a schematic diagram of an image sensor based on the Bayer color filter system.
  • the image sensor includes a micro lens 121, a Bayer color filter 122, and a photodiode 123.
  • the Bayer color filter 122 includes RGB color filters, and the RGB color filters are arranged on the grid of the photodiodes to form an RGB mosaic color filter system. Based on the biological characteristics of the largest number of green photoreceptor cells in the human retina, Bayer color filters are usually arranged in the form of RGGB. based on
  • FIG. 3 shows the structure of an image sensor based on the Bayer color filter system
  • FIG. 4 shows a schematic diagram of the structure of a color pixel unit in the image sensor.
  • a color pixel unit includes four color filters 122 and four corresponding photodiodes 123 pixel units.
  • the four color filters 122 are arranged in the form of RGGB, that is, the red color filter and the blue color filter are in a diagonal position, and the two green filters are in a diagonal position. Since the photosensitive area of the photodiode 123 is at the center of the area occupied by the photodiode pixel unit, a color pixel unit also includes an array of microlenses 121 above the color filter 122.
  • the microlens 121 array is used to converge the light signal to the photosensitive area of the photodiode 123 to ensure light utilization.
  • the microlens 121 array converges the incident light signals to the four color filters 122 respectively. After the light is filtered by the four color filters 122, they are transmitted to the photodiodes 123 covered by each, so as to obtain the light intensity information and the image at the same time. Approximate color information, after the software difference algorithm, can optimize and restore the closest true color image.
  • FIG. 5 shows a schematic diagram of the luminous flux of one spectral channel in a color pixel unit.
  • the filter when the incident light is white light, that is, the light signal contains all wavelengths of 400-700 nanometers, when the color filter is an ideal color filter effect, the filter The theoretical maximum value of the luminous flux after color is only 1/3 of the incident luminous flux; when the incident light is red light or blue light, the theoretical maximum luminous flux after color filtering is 1/4 of the incident luminous flux; when the incident light is green light, Since there are two green channels, the theoretical maximum value of the luminous flux after color filtering is 1/2 of the incident luminous flux. In fact, in reality, the color filter effect of the color filter cannot be perfect, that is, its color filter and light transmission efficiency cannot reach 100%, so the actual light utilization rate will be lower. When the incident light is white light, the total light utilization rate is only about 25%; when the incident light is red light or blue light, the light utilization rate is about 15%, and when the incident light is green light, the light utilization rate is about 30%.
  • the color filter system is replaced by a metasurface with spectral light splitting function.
  • the direction of reflected light and transmitted light not only depends on the refractive index of the interface material, but also depends on the phase gradient distribution on the interface.
  • the phase gradient distribution can be calculated by a formula, such as According to the spectroscopic function of the metasurface and the generalized Snell's law, the required spatial phase distribution can be calculated, and then the required geometric phase is generated at the required wavelength through the anisotropic nanofin structure, and the spectral spectroscopy function can be realized.
  • all metasurfaces use the geometric phase generated by the anisotropic nanofin structure to realize the light splitting function.
  • nanofin structure An inherent characteristic of the geometric phase is that it only works on one kind of circularly polarized light, and the other circularly polarized light will become useless stray light and cannot be used. Therefore, up to 50% of the light can be used.
  • another inherent characteristic of the nanofin structure is that each nanofin structure produces the same geometric phase for light of different frequencies. Therefore, it is necessary to realize the light splitting function of different frequencies through the geometric phase generated by the nanofin structure. Nanofins of different sizes can be placed in a unit structure, and nanofins of each size act on different frequency bands to achieve the effect of light splitting. However, this will inevitably result in a very low light utilization rate, because nanofins of different sizes will negatively scatter light in non-corresponding operating frequency bands.
  • the present application provides a spectroscopic color filter device applied to an image sensor to improve light utilization.
  • a spectroscopic color filter device applied to an image sensor to improve light utilization.
  • integrated pixel-level light-splitting devices efficient pixel-level spectrum light-splitting functions are realized, and the light utilization rate of the color image sensor is improved.
  • the present application provides an image sensor that includes a light splitting filter device and a photoelectric conversion unit.
  • the light splitting filter device is used to refract incident light so that light of different frequency bands can be transmitted to the corresponding photoelectric conversion unit. Color area.
  • FIG. 7 is a schematic diagram of the structure of a color splitting filter device provided in this application.
  • the spectroscopic color filter device includes: a metasurface 701 and a substrate 702.
  • the array of the metasurface 701 is arranged on the top of the substrate 702, or the top of the substrate 702 is used to carry the metasurface.
  • the metasurface 701 includes an array of at least one columnar structure.
  • the array of the metasurface 701 is used to refract light, and the metasurface 701 includes two media with different refractive indexes.
  • the metasurface can be divided into multiple grids, and each grid is filled with a medium such as titanium dioxide or air.
  • the metasurface includes a plurality of sub-units, and each sub-unit includes an array formed by a plurality of columnar structures.
  • each columnar structure in the plurality of columnar structures may include one of a triangle, a quadrilateral, a hexagon, etc., and the shape of each columnar structure in the plurality of columnar structures may be the same or Are not the same. It can be understood that the shape of the top surface of each columnar structure on the metasurface is a shape that can be seamlessly spliced, and the top surface is a direction that faces the metasurface and is perpendicular to the metasurface.
  • the metasurface includes an array formed by a plurality of columnar structures.
  • the shape of the top surface of each columnar structure on the metasurface is a shape that can be seamlessly spliced, which may be caused by the similarity of the columnar structures.
  • the structure is spliced into a larger structure.
  • the columnar structure may be a cube structure, and multiple cubes may be spliced into a rectangular parallelepiped shape or other irregular shapes due to proximity.
  • the substrate 702 is usually composed of a material whose light transmittance is higher than a certain value, such as silicon dioxide, polymethyl methacrylate (PMMA), or polycarbonate (PC). Alternatively, the substrate 702 may also be a hollow structure to ensure high transmittance.
  • a material whose light transmittance is higher than a certain value such as silicon dioxide, polymethyl methacrylate (PMMA), or polycarbonate (PC).
  • the substrate 702 may also be a hollow structure to ensure high transmittance.
  • the structure of the image sensor including the spectroscopic filter device may be as shown in FIG. 8, the bottom of the substrate is arranged on the surface or the top of the photoelectric conversion unit 703 in the image sensor.
  • the photoelectric conversion unit 703 includes an array for photoelectric conversion.
  • the array of the photoelectric conversion unit is divided into a plurality of color regions, and the metasurface is used to refract incident light and transmit it to the corresponding color region in the array of the photoelectric conversion unit through the substrate.
  • each pixel unit in the photoelectric conversion unit can be divided into four color areas, such as red, green, green, and blue (RGGB).
  • RGGB red, green, green, and blue
  • the photoelectric conversion unit array can be divided into a plurality of color units (or can also be called pixel units or color pixel units), each color unit includes at least four color areas, each color unit corresponds to one of the subsurface Unit, each sub-unit refracts the incident light and transmits it to the color area in the corresponding color unit via the substrate.
  • the metasurface can be understood as being arranged above the surface of the photoelectric conversion unit, and the area corresponding to each color unit in the metasurface includes a plurality of columnar structures, and the plurality of columnar structures are used to reflect incident light to In the corresponding color area in the color cell below it.
  • the structure of the metasurface 701 shown in FIG. 8 is a sub-unit, and the photoelectric conversion unit 703 can be understood as a color unit including four color regions.
  • the one subunit corresponds to a color unit, and the subunit is used to refract the incident light and transmit it to the corresponding color area in the color unit via the substrate 702.
  • the metasurface can include multiple subunits, each subunit includes an array formed by multiple columnar structures, and the structure of the array of each subunit can be the same. After the structure of a subunit is determined, it is determined The structure of the metasurface in the image sensor. Of course, the structure of the array of each subunit may also be different, which can be specifically adjusted according to actual application scenarios. In the following embodiments of the present application, only the structure of one of the subunits is used as an example for description, which will not be repeated hereafter.
  • the spectroscopic color filter device provided in the embodiment of the present application, light of different colors is refracted by the array formed by the columnar structure in the metasurface.
  • the incident light is transmitted to the sensor after being refracted by the metasurface.
  • the corresponding color area in the photoelectric conversion unit to achieve light splitting.
  • the spectroscopic filter device has a dielectric supersurface or a dielectric diffractive surface, has the structural characteristics of a second-order two-dimensional code pattern, and has a variety of spectrum channels to achieve the function of splitting multiple colors and achieving efficient splitting.
  • the array on the metasurface structure can refract the incident light, reduce the scattering phenomenon, and improve the light utilization rate.
  • the metasurface diffracts the incident light, so that the light of different frequency bands can be transmitted to the corresponding color area in the photoelectric conversion unit. Especially in the sub-wavelength scene, the metasurface diffracts the incident light.
  • the super-surface provided in this application can diffract light in different frequency bands, and improve the light utilization rate.
  • the structure of the array of the metasurface 701 may include at least two media with different refractive indices. Taking two media as an example, at least one of the materials may form a columnar structure and form an array of the metasurface.
  • the material of the metasurface includes one or more of the following: high refractive index materials such as titanium dioxide, gallium nitride, or silicon carbide.
  • the array of the metasurface may be a columnar structure composed of titanium dioxide, a plurality of columnar structures form an array, and the other medium in the metasurface may be air.
  • the metasurface may be composed of titanium dioxide and air. The refractive index of titanium dioxide is higher than that of air.
  • the structure of the metasurface may be as shown in FIG. 9A.
  • the material of the plurality of columnar structures may be titanium dioxide, and the other medium may be air. It can be understood that the columnar structure formed by titanium dioxide and the air form an array.
  • the top view of the array can be shown in Figure 9B, which is equivalent to gridding the metasurface and dividing it into multiple networks.
  • the size of each grid can be the same or different.
  • each grid is the same size.
  • the square network Take the square network as an example.
  • the height of the columnar structure on the metasurface 701 may be 500 nm
  • the width of each square grid may be 100 nm
  • the transparent substrate 702 is made of silica glass and has a thickness of 3.5 um.
  • the sensor pixel size targeted by the metasurface is 800nm, that is, the size of the metasurface corresponding to a pixel unit is 1.6um.
  • Subsequent preparation of the spectroscopic device may obtain the metasurface by filling the medium in the grid.
  • Each medium may have a columnar structure, and the size and shape of each columnar structure may be the same or different.
  • one of the media may be air, and the other may be a material with a refractive index different from that of air. It saves materials, and can improve the production efficiency of the spectroscopic color filter device.
  • FIG. 10 shows a schematic structural diagram of a color pixel unit in an embodiment of the present application.
  • a color pixel unit may include a super-surface 701 and four adjacent two-dimensionally arranged photoelectric conversion elements located under the super-surface structure.
  • the four photoelectric conversion elements correspond to the photoelectric conversion element A, the photoelectric conversion element B, the photoelectric conversion element C, and the photoelectric conversion element D in FIG. 10(b), respectively.
  • the four photoelectric conversion elements can be arranged in an RGGB manner.
  • the photoelectric conversion element A, the photoelectric conversion element B, the photoelectric conversion element C, and the photoelectric conversion element D can respectively correspond to the three frequency bands of red light, green light, green light and blue light.
  • the metasurface 701 can focus red light, green light, and blue light on the photosensitive positions of the photoelectric conversion element A, the photoelectric conversion element B, the photoelectric conversion element C, and the photoelectric conversion element D, respectively.
  • a spatial transmission phase is generated in the tangential direction of the array of the metasurface 701 to obtain a spatial transmission phase gradient.
  • the spatial transmission phase gradient is used to transmit the optical signal of each frequency band to the photoelectric conversion element corresponding to each frequency band.
  • the transmission phase may also be referred to as the transmission phase.
  • the existence of the spatial transmission phase gradient enables the incident optical signal to form a certain resonance effect with the metasurface 701.
  • different transmission phase changes will be produced in the metasurface 701, and thus Changing the refraction angle of the optical signal, that is, controlling the propagation direction of the optical signal, transmits the optical signal of different frequency bands to the photoelectric conversion element of different frequency bands.
  • the colors corresponding to each color unit include at least two same colors, and the surface of the columnar structure included in the supersurface area above each color unit forms an angularly symmetrical shape.
  • the colors corresponding to every four pixels that form a matrix arrangement in the photoelectric conversion unit can be arranged in the manner of RGGB, for example, the color corresponding to the color area in the upper left corner and the upper right corner is green, and the colors corresponding to the other two corners are red.
  • the top view of the array composed of the structures on the metasurface can be a symmetrical structure, so that the incident light can pass through the metasurface. The structure is refracted and transmitted to the corresponding color area in the photoelectric conversion unit.
  • FIG. 11 shows a schematic diagram of an array of photoelectric conversion units 220.
  • each photoelectric conversion unit 703 may correspond to 4 photoelectric conversion elements, and the 4 photoelectric conversion elements are arranged in an RGGB manner.
  • an anti-emission plate can be provided in the photoelectric conversion unit to reduce the reflection of the light signal by the photoelectric conversion unit and further improve the light utilization rate.
  • the number of photoelectric conversion elements in one photoelectric conversion unit 703 shown in FIG. 10 and FIG. 11 is only for illustration. In practice, the number of photoelectric conversion elements may be more or less.
  • the photoelectric conversion element does not constitute a limitation to the embodiment of the present application.
  • an array composed of columnar structures is arranged on the super surface of the color separation filter device to achieve refraction of light in different frequency bands.
  • this application refracts the light of different frequency bands, so that the light of each frequency band is transmitted to the corresponding area in the photoelectric conversion unit, avoiding the low light utilization rate caused by the filtering of the color filter. .
  • the light is refracted by the nanofin structure, which only affects one kind of circularly polarized light, and the other circularly polarized light will become useless stray light and cannot be used. Therefore, the light utilization rate is greatly reduced.
  • the spectroscopic filter device provided by the present application can refract all incident polarized light, not just one of the circularly polarized lights, and has little dependence on polarization. Therefore, the spectroscopic filter device provided by the present application The light utilization rate can be greatly improved.
  • Nanofins of different sizes can only be placed in a unit structure, and nanofins of each size act on different frequency bands to achieve the effect of light splitting. However, this will inevitably lead to a very low light utilization rate, because nanofins of different sizes will negatively scatter light in non-corresponding operating frequency bands.
  • the metasurface array structure can be composed of at least two media with different refractive indexes, and the columnar structure has the required response to light of different frequency bands, thereby avoiding the refracting of different frequency bands by nanofins of different sizes.
  • the problem of low utilization rate of non-refracted light caused by the increased light has further improved the utilization rate of light.
  • the surface of the photoelectric conversion unit may further include an anti-reflection layer or an anti-reflection layer is provided between the surface of the photoelectric conversion unit and the substrate to reduce the reflection of incident light and improve the light utilization rate.
  • a color filter structure is further provided between the photoelectric conversion unit 703 and the substrate 702.
  • the color filter structure is divided into a plurality of color filter regions, and each color filter region covers a corresponding color region. And the color corresponding to each color area is the same as the color transmitted by the filter area covered on each color area.
  • the color filter structure can be a four-color filter or other medium that penetrates a designated frequency band.
  • a color filter 704 may be provided between the photoelectric conversion unit and the substrate.
  • the color filter may be divided into a plurality of color filter regions, which are used to treat light other than light in a specific frequency band. The light is filtered. For example, if the color area corresponding to the color filter is green, the color filter can transmit green and filter colors other than green.
  • the light transmitted to each color area in the photoelectric conversion unit can be filtered, and the light that is not in a specific frequency band can be filtered out, thereby avoiding the photoelectric conversion unit from affecting the light signal.
  • the interference of the conversion further improves the light utilization rate.
  • a lens is further provided between each color filter area and the substrate.
  • a micro convex lens 705 (referred to as a micro lens) is provided between each color filter area and the substrate.
  • the size of each microlens is the same as the size of the color filter area it covers, so that the light transmitted to the color filter area is concentrated, so as to reduce the scattering of the light transmitted to the color area and further improve the light utilization efficiency. Therefore, in the embodiment of the present application, the color filter and the micro lens can be used in the color splitting filter device to reduce the crosstalk of each channel.
  • light of multiple frequency bands of colors corresponding to multiple color regions includes one or more of green, red, blue, or infrared radiation (IR).
  • IR infrared radiation
  • the number of spectroscopic spectrum channels of the spectroscopic filter device provided in this application is not less than two, and the frequency band of the spectrum ranges from ultraviolet to near-infrared, depending on the use of the image sensor and the spectral response range of the photosensitive layer; the number of spectra and channels
  • the arrangement depends on the purpose of the image sensor; for example, for visible light imaging, the spectral frequency range is 400-700nm visible light range, the number of spectra is 3, and the channel arrangement is RGGB; for multispectral imaging, the tiled frequency range is 400-700 ,
  • the number of spectrums can be 7; for visible light & near-infrared imaging, the frequency range of the spectrum is 400-1000nm, the number of spectrums is 4, and the channel arrangement can be RGB&IR. Therefore, in the embodiments of the present application, it is possible to realize the spectroscopy of a variety of visible light or invisible light, adapt to a variety of scenarios, and have a strong generalization ability.
  • the foregoing exemplified the structure of the spectroscopic filter device provided by the present application. From the above structure, it can be seen that the super-surface of the spectroscopic filter device plays an important role in improving the light utilization efficiency, and the array of the super-surface can be arranged in many ways. In the following, the method for determining the super-surface array structure of the spectroscopic filter device will be introduced.
  • the present application provides a method for determining an array structure applied to an image sensor.
  • the image sensor includes a light splitting filter device and a photoelectric conversion unit.
  • the light splitting filter device please refer to the aforementioned light splitting filter device in FIGS. 7-13. It will not be repeated here, and the detailed steps of the method for determining the array structure of the image sensor provided in the present application will be introduced below.
  • the structure of the multiple arrays may be obtained from a search in a preset search space, or may be a randomly generated structure.
  • Each array can be a grid structure or a honeycomb structure.
  • the height of each structure can be the same or different.
  • the height of each structure can also be searched in a preset search space. It can be understood that different array structures and height ranges can be preset in the search space, and then multiple array structures and the height corresponding to each array structure can be sampled from the search space.
  • multiple array structures can be generated in advance to form a search space, and then the available array structures can be screened according to actual application scenarios, so as to quickly obtain multiple arrays and improve the efficiency of obtaining multiple arrays.
  • one or more two-dimensional code images can be randomly generated, and then an array is constructed based on the multiple two-dimensional code images.
  • the size of the metasurface to be constructed can be preset, then the metasurface is gridded, divided into square grids or hexagonal grids, etc., and then each grid is randomly filled to obtain an array
  • the structure is shown in Figure 15.
  • the evaluation function is a function of calculating the light utilization efficiency of the spectroscopic filter device when multiple arrays are used as the metasurface of the spectroscopic filter device to obtain the light utilization efficiency of each array, and then determine the metasurface of the spectroscopic filter device according to the evaluation value The structure of the array.
  • N initial two-dimensional code structures can be randomly generated, each two-dimensional code structure is composed of N*N square areas, and each area can be one of two dielectric materials, such as air and titanium dioxide.
  • the second-order matrix composed of 0/1 composed of N*N represents the structure.
  • the height of the structure is a random height within 1um.
  • 1 represents titanium dioxide, and 0 represents air.
  • a simulation model is established based on the spectroscopic function of RGGB, Maxwell's equation is solved through simulation, and the average light utilization rate is calculated as the evaluation function as follows:
  • ⁇ r1 ⁇ r2 , ⁇ g 1 ⁇ ⁇ g2 , ⁇ b1 ⁇ b2 are the red, green, and blue light spectra, respectively
  • T r , T g , and T b are red, green, and blue light, respectively
  • the transmittance of the pixel area Specifically, for example, N image sensors corresponding to the two-dimensional code structure can be generated through simulation, and then the light utilization rate of each simulated image sensor may be calculated through the evaluation function, to obtain the light utilization rate corresponding to each array.
  • the light utilization efficiency can also be calculated by preparing the image sensor corresponding to each array, which is not limited in this application.
  • each array in the plurality of arrays After obtaining the evaluation value of each array in the plurality of arrays, determine whether there is an array with an evaluation value higher than the preset value in the plurality of arrays, and if the plurality of arrays includes at least one array with an evaluation value higher than the preset value, Then one of the arrays can be selected from the arrays whose evaluation value is higher than the preset value as the structure of the super-surface array of the spectroscopic filter device; if the multiple arrays do not include the array with the evaluation value higher than the preset value, you can get A new array until an array with an evaluation value higher than the preset value is obtained.
  • the array with the highest evaluation value can be selected from the multiple arrays with an evaluation value higher than 50% as the supersurface structure of the spectroscopic filter device.
  • one array is randomly selected from the plurality of arrays with an evaluation value higher than 50% as the structure of the super-surface of the spectroscopic filter device.
  • the multiple arrays are updated, and the super-surface structure of the spectroscopic filter device is determined according to the updated multiple arrays, that is, step 1402 is repeated. -1403, until an array with an evaluation value higher than the preset value is obtained.
  • the mutation rate corresponding to each of the multiple arrays can be determined based on the values of multiple evaluation values.
  • the mutation rate may specifically include the shape mutation rate or the height mutation rate.
  • the shape mutation rate is The probability or ratio of the shape variation of the array structure, etc.
  • the height variation rate is the probability or ratio of the height variation of the array, etc.; then, multiple arrays are mutated according to the variation rate corresponding to each array to obtain the updated
  • the multiple arrays may specifically vary the shapes of multiple arrays based on the shape variation rate, or vary the heights of multiple arrays based on the height variation rate.
  • the evaluation value of each array can be used to indicate the light utilization efficiency of each array after being substituted into the image sensor through simulation.
  • the difference between the light utilization rate and the mutation rate is The relationship can be a linear relationship or an exponential relationship, etc., and can be adjusted according to actual application scenarios.
  • the specific mutation method may be to rearrange the columnar structures in some regions of the array, exchange with the structure of some regions in other arrays, etc.
  • the specific mutation method can be adjusted according to actual application scenarios. If the height variation rate is 10%, the height of the array is increased or decreased by 10% to obtain the height after variation.
  • the specific mutation method can be adjusted according to actual application scenarios.
  • the shape and height variation rate of each array can be determined based on the evaluation value of each array, so as to complete the variation of the array.
  • the higher the evaluation value the lower the variation rate corresponding to the array. Adjust the structure of the array so that the structure of the new array is closer to the preset value, so that the array with higher light utilization efficiency can be subsequently screened out.
  • the probability value corresponding to each array in the multiple arrays can be determined according to the values of multiple evaluation values; then, the multiple arrays are sampled according to the probability value corresponding to each array, Obtain multiple intermediate structures; subsequently, determine the variation rate of multiple intermediate structures, including shape variation rate or height variation rate, etc., according to the evaluation values of multiple intermediate structures; The structure is mutated, and new multiple arrays are obtained.
  • the specific mutation method may be to rearrange the columnar structures in some regions of the array, exchange with the structure of some regions in other arrays, etc. The specific mutation method can be adjusted according to actual application scenarios.
  • the light utilization rate corresponding to array 1 is 25%
  • the light utilization rate corresponding to array 2 is 30%
  • the light utilization rate of array 3 is 26%, etc.
  • the probability of array 1 is 10
  • the probability of array 2 is 25%
  • the probability of array 3 is 13%, etc.
  • one or more samples can be taken based on the probability of each array.
  • the method of setting the corresponding probability for each array may include: Where i represents the i-th two-dimensional code structure, F i is the evaluation function of the i-th structure, and n can be an integer greater than or equal to 1.
  • each sampling can be based on the probability of each array. Different batches of sampling may sample the same or different arrays. Therefore, in the embodiments of the present application, the probability of each array can be set based on the light utilization rate of each array, so that the array with the higher the light utilization rate during subsequent sampling has the greater the probability of being sampled.
  • the sampled array is mutated to obtain a new array.
  • an optimization algorithm such as genetic algorithm, simulated annealing algorithm, or gradient descent can be used to reversely obtain an array that meets the light utilization rate demand target, thereby improving the light splitting efficiency.
  • the light utilization efficiency of color filters and image sensors can be used to reversely obtain an array that meets the light utilization rate demand target, thereby improving the light splitting efficiency.
  • the foregoing describes in detail the spectroscopic filter device, image sensor, and the method for determining the array structure of the application and image sensor provided by this application.
  • the following is based on the foregoing spectroscopic filter device, image sensor, and the method for determining the array structure of the application and image sensor.
  • the preparation method of the image sensor provided by the application is introduced in detail.
  • FIG. 16 a schematic flow chart of a method for manufacturing an image sensor provided by the present application is as follows.
  • a photoelectric conversion unit is prepared.
  • the photoelectric conversion unit is used to convert an optical signal into an electrical signal.
  • the photoelectric conversion unit includes an array for photoelectric conversion.
  • the array of the photoelectric conversion unit is divided into a plurality of color regions.
  • a spectroscopic color filter device is prepared on the surface of the photoelectric conversion unit.
  • the spectroscopic color filter device includes a supersurface and a substrate.
  • the array in the supersurface is arranged on the top of the substrate.
  • the bottom of the substrate is arranged on the surface or the top of the photoelectric conversion unit.
  • the supersurface includes a plurality of subunits, and each subunit includes An array formed by a plurality of columnar structures, and the metasurface includes at least two media with different refractive indexes.
  • the photoelectric conversion unit includes an array for photoelectric conversion.
  • the array of photoelectric conversion units is divided into multiple color regions. The light is refracted to the corresponding color area in the array of photoelectric conversion units.
  • the array of photoelectric conversion units can be divided into multiple color units, each color unit includes at least four color regions, each subunit in the metasurface corresponds to a color unit, and each subunit refracts incident light and transmits it to the corresponding The color cell in the color area.
  • each subunit may be the same or different.
  • CMOS process can be used to integrate an array of photoelectric conversion units and an array of super-surface structures.
  • the metasurface may include an array composed of two media, titanium dioxide and air, and after determining the array structure of the metasurface, columnar structures composed of titanium dioxide may be filled in the array.
  • step 1602 may include depositing a substrate on the array of photoelectric conversion units, and preparing a microstructure on the substrate.
  • a substrate can be prepared on the surface of the photoelectric conversion unit, and an array of metasurfaces can be prepared on the top of the substrate.
  • the array formed by the columnar structure in the metasurface refracts light of different colors, and the incident light is After being refracted by the metasurface, it is transmitted to the corresponding color area in the photoelectric conversion unit, thereby realizing light splitting.
  • the spectroscopic filter device has a dielectric supersurface or a dielectric diffractive surface, has the structural characteristics of a second-order two-dimensional code pattern, and has a variety of spectrum channels to achieve the function of splitting multiple colors and achieving efficient splitting.
  • the array on the metasurface structure can refract the incident light, reduce the scattering phenomenon, and improve the light utilization rate of the image sensor.
  • a color filter structure can also be prepared between the photoelectric conversion unit and the substrate.
  • the color filter structure is divided into a plurality of color filter regions, and each color filter region covers a corresponding color region, and The color corresponding to each color area is the same as the color transmitted by the color filter area covered on each color area, and each color filter area is used to filter light of colors other than the colors corresponding to the covered color area.
  • a lens can also be prepared between each color filter area and the substrate.
  • light of multiple frequency bands of colors corresponding to multiple color regions includes one or more of green, red, blue, or infrared light.
  • the material of the supersurface includes one or more of the following: titanium dioxide, gallium nitride, or silicon carbide.
  • the colors corresponding to each color unit include at least two same colors, and the surface of the columnar structure included in the supersurface area above each color unit forms an angularly symmetrical shape.
  • an array structure of the metasurface can also be constructed. Exemplarily, referring to FIG. 17, in conjunction with the method of constructing a metasurface array structure, the process of the method for manufacturing the image sensor provided in the present application will be described in more detail, as described below.
  • the structure of the multiple arrays is evaluated by the evaluation function, and an evaluation value corresponding to each of the multiple arrays is obtained.
  • steps 1701-1705 can refer to the aforementioned steps 1401-1405, which will not be repeated here.
  • steps 1706-1707 can refer to the aforementioned steps 1601-1602, which will not be repeated here.
  • the array structure of the metasurface can also be determined, so as to obtain an image sensor with higher light utilization efficiency. It can be understood that, based on the set light utilization requirements, optimization algorithms such as genetic algorithms, simulated annealing algorithms, or gradient descent can be used to reversely obtain an array that meets the light utilization requirements, thereby improving the spectral filter device and The light utilization rate of the image sensor.
  • optimization algorithms such as genetic algorithms, simulated annealing algorithms, or gradient descent can be used to reversely obtain an array that meets the light utilization requirements, thereby improving the spectral filter device and The light utilization rate of the image sensor.
  • FIG. 18 is a spectrum diagram of the light utilization efficiency of the spectroscopic device in the visible light band of 400-700 nm, the abscissa is the wavelength, and the ordinate is the transmittance.
  • Tb represents the light transmittance reaching the blue photosensitive pixel element in the lower right corner
  • Tg and Tg2 represent the light transmittance reaching the upper right and lower left corners of the two photosensitive pixel elements
  • Tr represents the transmittance reaching the red photosensitive pixel element in the upper left corner rate.
  • this embodiment increases the light utilization rate of visible light to 55.9%, which is about 224% of the light utilization rate of the conventional color filter.
  • the utilization rate of red light is 73.7%, which is about 393% of the traditional color filter
  • the utilization rate of green light is 47.9%, which is about 127% of the traditional color filter
  • the utilization rate of blue light is 47.3%, which is about 252% of the light utilization rate of traditional color filters.
  • the light intensity distribution on the 3.5um plane from the bottom of the dielectric spectroscopic device layer is shown in Figure 19.
  • (a), (b) and (c) correspond to the wavelengths of 450nm, 536nm and 640nm, respectively. It can be seen that the red, green and blue lights are in accordance with The arrangement of the RGGB is focused on the four photosensitive pixel positions of the lower right, the lower left, the upper right and the upper left, respectively.
  • the spectral crosstalk is eliminated by adding a color filter layer, and the scattered light is less.
  • the present application uses a pixel-level spectral light splitting device to break through the theoretical limit of light utilization of a single color filter system through spectral light splitting, and improve the color image in principle.
  • the light utilization rate of the sensor For the super-surface technology of the nano-fin structure, the present invention uses a function-driven reverse design algorithm to design a second-order two-dimensional code structure, which has the advantages of high light splitting efficiency, low polarization dependence, and smaller matching photosensitive pixels.
  • the signal-to-noise ratio when shooting with the image sensor is improved, the quality of images shot under low-light conditions is improved, and the photographing performance under low-light conditions is improved.
  • the present application also provides an array structure construction device, which is used to perform the method of FIG. 14, and the device may include:
  • the first determining unit 2001 is used to determine the structure of multiple arrays
  • the evaluation unit 2002 is configured to evaluate the structure of the plurality of arrays through an evaluation function to obtain an evaluation value corresponding to each of the plurality of arrays, and the evaluation function is to calculate the plurality of arrays as the A function of the light utilization efficiency of the spectroscopic filter device when the super-surface of the spectroscopic filter device is super-surface;
  • the second determining unit 2003 is configured to determine the super-surface structure of the color separation filter device according to the evaluation value.
  • the color separation filter device is included in an image sensor.
  • the image sensor includes a color separation filter device and a photoelectric conversion unit.
  • the color device includes a supersurface and a substrate.
  • the photoelectric conversion unit includes an array for photoelectric conversion.
  • the spectroscopic filter device includes a supersurface and a substrate. The array in the supersurface is arranged on the top of the substrate, and the bottom of the substrate is set on the photoelectric.
  • the surface or top of the conversion unit, the metasurface includes an array composed of at least two media with different refractive indices, the array in the metasurface includes an array formed by at least one columnar structure, the array of photoelectric conversion units is divided into multiple color regions, the metasurface It is used to refract incident light to the corresponding color area in the array of photoelectric conversion units.
  • the array of photoelectric conversion units can be divided into multiple color units, each color unit includes at least four color areas, each color unit corresponds to a subunit, and each subunit refracts incident light and transmits it to the corresponding color unit. In the color area.
  • the first determining unit 2001 is specifically configured to: if the plurality of arrays include at least one array whose evaluation value is higher than the preset value, determine whether the evaluation value is higher than at least the preset value.
  • One of the arrays is selected as the structure of the super-surface array of the light-splitting color filter device;
  • the array structure construction device may further include: an update unit 2004, configured to update the multiple arrays if the multiple arrays do not include an array with an evaluation value higher than a preset value;
  • the second determining unit is further configured to determine the structure of the super-surface array of the light splitting filter device according to the updated multiple arrays.
  • the update unit 2004 is specifically configured to determine the mutation rate corresponding to each of the multiple arrays according to the values of the multiple evaluation values; according to the mutation corresponding to each of the arrays The multiple arrays are mutated at a rate to obtain updated multiple arrays.
  • the updating unit 2004 is specifically configured to determine the probability value corresponding to each of the multiple arrays according to the values of the multiple evaluation values; according to the probability corresponding to each of the multiple arrays Value, the plurality of arrays are sampled multiple times to obtain a plurality of intermediate structures; the mutation rate of the plurality of intermediate structures is determined according to the evaluation value of the plurality of intermediate structures; the mutation rate of the plurality of intermediate structures is determined according to the corresponding mutation of the plurality of intermediate structures The multiple intermediate structures are mutated at a rate to obtain new multiple arrays.
  • the colors corresponding to each color unit include at least two identical colors, and the surface of the columnar structure included in the supersurface area above each color unit forms an angularly symmetrical shape.
  • every at least four color regions arranged in a matrix can correspond to at least two of the same colors, and the colors corresponding to two symmetrical color regions can be the same.
  • This embodiment provides a possible arrangement of arrays suitable for metasurfaces. the way.

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Abstract

本申请实施例提供了一种图像传感器、分光滤色器件及图像传感器的制备方法，用于为提高入射至图像传感器的光的利用率。该图像传感器包括：超表面、衬底和光电转换单元；超表面中的阵列排列在衬底的顶部，超表面包括多个子单元，每个子单元包括多个柱状结构形成的阵列，衬底的底部设置于图像传感器中的光电转换单元的表面，超表面包括折射率不同的至少两种介质，每个彩色单元对应多个子单元中的其一个子单元，光电转换单元包括用于光电转换的阵列，光电转换单元的阵列分为多个颜色区域，超表面用于将入射光折射并经衬底传输至光电转换单元的阵列中对应的颜色区域，且每个子单元将入射光折射后传输至对应的彩色单元中的颜色区域。

Description

一种图像传感器、分光滤色器件及图像传感器的制备方法
本申请要求于2019年12月31日提交中国专利局、申请号为“PCT/CN2019/130438”、申请名称为“图像传感器及其制备方法和电子设备”的中国专利申请的优先权，其全部内容通过引用结合在本申请中。
本申请还要求于2020年11月19日提交中国专利局、申请号为“PCT/CN2020/130020”、申请名称为“一种图像传感器、分光滤色器件及图像传感器的制备方法”的中国专利申请的优先权，其全部内容通过引用结合在本申请中。
技术领域
本申请涉及成像领域，尤其涉及一种图像传感器、分光滤色器件及图像传感器的制备方法。
背景技术
图像传感器能够将光学影像转化为电信号，广泛应用于多种电子设备，例如，数码相机中。数码相机的硬件主要包括镜头组、图像传感器和电信号处理器等，镜头组用于将光学影像成像在图像传感器上，图像传感器用于将图像的光信号转化为模拟电信号并输入至电信号处理器，电信号处理器将模拟电信号转换为数字信号，经过数据处理后，输出照片。图像传感器作为光电转换器，是数码相机的核心部件之一，其性能直接决定输出照片的质量。
图像传感器的光电转换元件能够将不同强度的光信号转化为不同强度的电信号。但是，光电转换元件自身不能分辨光的频率，即不能分辨颜色。因此，利用不含有颜色采集层的图像传感器直接获得的图片是黑白的。为了获得彩色的图片，需要滤色系统作为颜色采集层获取图片的颜色信息。例如，利用人眼对红色绿色蓝色(red green blue，RGB)三原色光谱敏感的特点，将RGB滤色器排列在光电转换元件上，形成RGB马赛克式的拜耳滤色片系统，能够获得彩色的图片。然而，在现有方案中，对光的利用率都较低，例如，对于白光入射时的总光利用率仅有约25％；对于红光或蓝光入射的光利用率仅有约15％，绿光入射的光利用率约为30％等，因此，如何提高光利用率，成为亟待解决的问题。
发明内容
本申请实施例提供了一种图像传感器、分光滤色器件及图像传感器的制备方法，用于为提高入射至图像传感器的光的利用率。
有鉴于此，本申请第一方面提供一种图像传感器的，包括：超表面、衬底和光电转换单元；超表面包括多个子单元，每个子单元包括多个柱状结构形成的阵列，超表面中的阵列排列在衬底的顶部，衬底的底部设置于光电转换单元的表面(或者称为顶部)，超表面包括折射率不同的至少两种介质，光电转换单元包括用于光电转换的阵列，光电转换单元的阵列分为多个颜色区域，超表面用于将入射光折射并经衬底传输至光电转换单元的阵列中对应的颜色区域。
其中，光电转换单元的阵列可以分为多个彩色单元，每个彩色单元包括至少四个颜色区域，每个彩色单元对应一个子单元，且每个子单元将入射光折射后传输至对应的彩色单元中的颜色区域中。
因此，在本申请实施方式中，可以通过超表面上的至少两种折射率不同的介质形成的阵列，对入射光进行折射，使不同频段的光可以折射至光电转换单元中对应的颜色区域，提高了光利用率。并且，相对于设置拜耳滤色片，本申请提供的图像传感器的超表面可以对多种不同频段的光折射至对应的颜色区域，避免因过滤而导致的光利用率低的问题。可以理解为，超表面对入射光可以形成衍射，使不同频段的光可以传输至光电转换单元中对应的颜色区域，提高光利用率。
在一种可能的实施方式中，光电转换单元和衬底之间还设置有滤色结构，滤色结构分为多个滤色区域，且每个滤色区域覆盖一个对应的颜色区域，且每个颜色区域对应的颜色与每个颜色区域上覆盖的滤色区域透过的颜色相同。
本申请实施方式中，可以通过在光电转换单元和衬底之间还设置滤色结构，来对与颜色区域对应的频段的光不同的信号进行过滤，降低串扰。
在一种可能的实施方式中，每个滤色区域与衬底之间还设置有透镜。本申请还可以通过在每个滤色区域与衬底之间还设置透镜，来对入射至滤色区域的光进行汇聚。
在一种可能的实施方式中，多个颜色区域对应的多个频段的光，包括：绿色、红色、蓝色或者红外光中的一种或者多种。因此，本申请实施方式中，光电转换单元可以将多个频段的光信号转换为电信号，以便后续可以生成更多颜色通道的图像。
在一种可能的实施方式中，超表面的材料包括以下一种或者多种：二氧化钛、氮化镓或碳化硅。
在一种可能的实施方式中，每个彩色单元对应的颜色中至少包括两种相同的颜色，超表面中与每个彩色单元对应的区域中包括的柱状结构形成角对称的形状。
因此，每四个排列成矩阵的颜色区域可以对应至少两种相同的颜色，对称的两种颜色区域对应的颜色可能相同，本实施例提供了一种适用于超表面的阵列的可能的排列方式。
第二方面，本申请提供一种分光滤色器件，包括：超表面和衬底；
超表面包括多个子单元，每个子单元包括多个柱状结构组成的阵列，超表面中的阵列排列在衬底的顶部，超表面包括折射率不同的至少两种介质，超表面用于将对入射光产生折射，衬底用于传输经超表面折射后的光。
因此，在本申请实施方式中，可以通过超表面上的至少两种折射率不同的介质形成的阵列，对入射光进行折射，使不同频段的光可以折射至不同区域，提高了光利用率。并且，相对于设置拜耳滤色片，本申请提供的分光滤色器件的超表面可以对多种不同频段的光折射至对应的颜色区域，避免因过滤而导致的光利用率低的问题。
在一种可能的实施方式中，分光滤色器件可以应用于图像传感器，该图像传感器中包括光电转换单元，衬底设置于光电转换单元的表面，光电转换单元包括用于光电转换的阵列，光电转换单元的阵列分为多个颜色区域，超表面将入射光折射并经衬底传输至光电转换单元的阵列中对应的颜色区域。可以理解为，超表面对入射光可以形成衍射，使不同频 段的光可以传输至光电转换单元中对应的颜色区域，提高光利用率。
其中，光电转换单元的阵列可以分为多个彩色单元，每个彩色单元包括至少四个颜色区域，每个彩色单元对应超表面中的一个子单元，且每个子单元将入射光折射后传输至对应的彩色单元中的颜色区域中。在一种可能的实施方式中，光电转换单元和衬底之间还设置有滤色结构，滤色结构分为多个滤色区域，且每个滤色区域覆盖一个对应的颜色区域，且每个颜色区域对应的颜色与每个颜色区域上覆盖的滤色区域透过的颜色相同。本申请实施方式中，可以通过在光电转换单元和衬底之间还设置滤色结构，来对与颜色区域对应的频段的光不同的信号进行过滤，降低串扰。
在一种可能的实施方式中，每个滤色区域与衬底之间还设置有透镜。本申请还可以通过在每个滤色区域与衬底之间还设置透镜，来对入射至滤色区域的光进行汇聚。
在一种可能的实施方式中，多个颜色区域对应的颜色多个频段的光，包括：绿色、红色、蓝色或者红外光中的一种或者多种。因此，本申请实施方式中，光电转换单元可以将多个频段的光信号转换为电信号，以便后续可以生成更多颜色通道的图像。
在一种可能的实施方式中，超表面的材料包括以下一种或者多种：二氧化钛、氮化镓或碳化硅。
在一种可能的实施方式中，每个彩色单元对应的颜色中至少包括两种相同的颜色，超表面中与每个彩色单元对应的区域中包括的柱状结构形成角对称的形状。
第三方面，本申请提供一种图像传感器的制备方法，包括：
制备光电转换单元，光电转换单元用于将光信号转换为电信号，光电转换单元包括用于光电转换的阵列，光电转换单元的阵列分为多个颜色区域；
在光电转换单元的表面制备分光滤色器件，分光滤色器件包括超表面和衬底，超表面包括多个子单元，每个子单元包括个柱状结构形成的阵列，超表面中的阵列排列在衬底的顶部，衬底的底部设置于光电转换单元的表面，超表面包括折射率不同的至少两种介质，光电转换单元包括用于光电转换的阵列，光电转换单元的表面为接收光信号的面，光电转换单元的阵列分为多个颜色区域，超表面用于将入射光折射至光电转换单元的阵列中对应的颜色区域。
其中，光电转换单元的阵列可以分为多个彩色单元，每个彩色单元包括至少四个颜色区域，每个彩色单元对应超表面中的一个子单元，且每个子单元将入射光折射后传输至对应的彩色单元中的颜色区域中。因此，在本申请实施方式中，制备得到的图像传感器其中分光滤色器件的超表面上具有至少两种折射率不同的介质形成的阵列，对入射光进行折射，使不同频段的光可以折射至光电转换单元中对应的颜色区域，提高了光利用率。并且，相对于设置拜耳滤色片，本申请提供的分光滤色器件的超表面可以对多种不同频段的光折射至对应的颜色区域，避免因过滤而导致的光利用率低的问题。
在一种可能的实施方式中，在光电转换单元的表面制备分光滤色器件之前，方法还包括：确定多个阵列，并将多个阵列作为分光滤色器件的超表面的结构，得到多种分光结构；通过预设的评价函数得到与多种分光结构一一对应的多个评价值，评价函数为计算分光结构的光利用率的函数；若多个评价值中包括高于预设值的至少一个评价值，则从多种分光 结构中筛选出第一分光结构作为分光滤色器件的结构，第一分光结构的评价值高于预设值。
因此，本申请实施方式中，可以通过预先建立的仿真模型来计算每个阵列的光利用率，从而得到光利用率超过预设值的阵列，进而制备得到光利用率超过预设值的图像传感器。可以理解为，可以基于设定的光利用率的需求目标，通过遗传算法、模拟退火算法或者梯度下降等优化算法，来逆向得到符合光利用率的需求目标的阵列，从而提高分光滤色器件和图像传感器的光利用率。
在一种可能的实施方式中，方法还可以包括：若多个评价值中不包括高于预设值的至少一个评价值，则重新确定多个阵列，并根据重新确定的多个阵列确定分光结构作为分光滤色器件的结构。
因此，在本申请实施方式中，若多个阵列中不包括评价值高于预设值的阵列，则可以对多个阵列进行更新，得到新的多个阵列，直到得到评价值高于预设值的阵列。
在一种可能的实施方式中，重新确定多个阵列，可以包括：根据多个评价值的值，确定多个阵列中每个阵列对应的变异率；根据每个阵列对应的变异率对多个阵列进行变异，得到更新后的多个阵列。本申请实施方式中，可以通过变异来得到新的阵列，直到得到评价值高于预设值的阵列。
在一种可能的实施方式中，所述每个阵列对应的变异率包括形状变异率和/或高度变异率，所述形状变异率包括对所述每个阵列的形状进行变异的概率或者比例，所述高度变异率包括对所述每个阵列的高度进行变异的概率或者比例。因此，本申请实施例可以从形状或高度等不同维度对阵列进行变异，得到多种不同的阵列结构。
在一种可能的实施方式中，重新确定多个阵列，可以包括：根据多个评价值的值，确定多个阵列中每个阵列对应的概率值；根据每个阵列对应的概率值，对多个阵列进行多次采样，得到多个中间结构；根据多个中间结构的评价值确定多个中间结构的变异率；根据多个中间结构对应的变异率对多个中间结构进行变异，得到新的多个阵列。
因此，本申请实施方式中，可以根据每个阵列的评价值确定每个阵列对应的概率值，然后基于每个阵列的概率值来进行采样，从而筛选出评价值更高的阵列，并对筛选出来的阵列进行变异，得到新的阵列，直到得到评价值高于预设值的阵列。
在一种可能的实施方式中，方法还可以包括：在光电转换单元和衬底之间制备滤色结构，滤色结构分为多个滤色区域，且每个滤色区域覆盖一个对应的颜色区域，且每个颜色区域对应的颜色与每个颜色区域上覆盖的滤色区域透过的颜色相同，每个滤色区域用于过滤除所覆盖颜色区域对应的颜色之外的颜色的光。
在一种可能的实施方式中，方法还可以包括：在每个滤色区域与衬底之间制备透镜。本申请还可以通过在每个滤色区域与衬底之间还设置透镜，来对入射至滤色区域的光进行汇聚。
在一种可能的实施方式中，多个颜色区域对应的多个频段的光，包括：绿色、红色、蓝色或者红外光中的一种或者多种。因此，本申请实施方式中，光电转换单元可以将多个频段的光信号转换为电信号，以便后续可以生成更多颜色通道的图像。
在一种可能的实施方式中，超表面的材料包括以下一种或者多种：二氧化钛、氮化镓 或碳化硅。
在一种可能的实施方式中，每个彩色单元对应的颜色中至少包括两种相同的颜色，超表面中与每个彩色单元对应的区域中包括的柱状结构形成角对称的形状。
第四方面，本申请还提供一种电子设备，该电子设备中可以包括如前述第一方面中的图像传感器，或者由第三方面制备得到的图像传感器等。
第五方面，本申请提供一种应用于图像传感器的阵列结构确定方法，所述图像传感器包括分光滤色器件和光电转换单元，所述分光滤色器件包括超表面和衬底，所述光电转换单元包括用于光电转换的阵列，所述分光滤色器件包括超表面和衬底，所述超表面中的阵列包括多个子单元，每个子单元包括多个柱状结构形成的阵列，所述超表面中的阵列排列在所述衬底的顶部，所述衬底的底部设置于光电转换单元的表面，所述超表面包括折射率不同的至少两种介质，所述光电转换单元的阵列分为多个颜色区域，所述超表面用于将入射光折射至所述光电转换单元的阵列中对应的颜色区域，所述方法包括：确定多个阵列的结构；通过评价函数对所述多个阵列的结构进行评估，得到与所述多个阵列中每个阵列对应的评价值，所述评价函数为计算所述多个阵列作为所述分光滤色器件的超表面时所述分光滤色器件的光利用率的函数；根据所述评价值确定所述分光滤色器件的超表面的结构。
其中，光电转换单元的阵列可以分为多个彩色单元，每个彩色单元包括至少四个颜色区域，每个彩色单元对应超表面中的一个子单元，且每个子单元将入射光折射后传输至对应的彩色单元中的颜色区域中。
在一种可能的实施方式中，所述根据所述评价值确定所述分光滤色器件的超表面的阵列的结构，可以包括：若所述多个阵列中包括评价值高于预设值的至少一个阵列，则从所述评价值高于预设值的至少一个阵列中选择其中一个阵列作为所述分光滤色器件的超表面的阵列的结构；若所述多个阵列中不包括评价值高于预设值的阵列，则更新所述多个阵列，并根据更新后的多个阵列确定为所述分光滤色器件的超表面的阵列的结构。
在一种可能的实施方式中，所述更新所述多个阵列，可以包括：根据所述多个评价值的值，确定所述多个阵列中每个阵列对应的变异率；根据所述每个阵列对应的变异率对所述多个阵列进行变异，得到更新后的多个阵列。
在一种可能的实施方式中，所述每个阵列对应的变异率包括形状变异率和/或高度变异率，所述形状变异率包括对所述每个阵列的形状进行变异的概率或者比例，所述高度变异率包括对所述每个阵列的高度进行变异的概率或者比例。
在一种可能的实施方式中，所述更新所述多个阵列，可以包括：根据所述多个评价值的值，确定所述多个阵列中每个阵列对应的概率值；根据所述每个阵列对应的概率值，对所述多个阵列进行多次采样，得到多个中间结构；根据所述多个中间结构的评价值确定所述多个中间结构的变异率；根据所述多个中间结构对应的变异率对所述多个中间结构进行变异，得到新的多个阵列。
在一种可能的实施方式中，每个彩色单元对应的颜色中至少包括两种相同的颜色，超表面中与每个彩色单元对应的区域中包括的柱状结构形成角对称的形状。
第六方面，本申请提供一种阵列结构构建装置，包括：
第一确定单元，用于确定多个阵列的结构；
评价单元，用于通过评价函数对所述多个阵列的结构进行评估，得到与所述多个阵列中每个阵列对应的评价值，所述评价函数为计算所述多个阵列作为所述分光滤色器件的超表面时所述分光滤色器件的光利用率的函数；
第二确定单元，用于根据所述评价值确定所述分光滤色器件的超表面的结构，该分光滤色器件包括于图像传感器中，图像传感器包括分光滤色器件和光电转换单元，分光滤色器件包括超表面和衬底，光电转换单元包括用于光电转换的阵列，分光滤色器件包括超表面和衬底，超表面中的阵列排列在衬底的顶部，衬底的底部设置于光电转换单元的表面，超表面包括折射率不同的至少两种介质构成的阵列，超表面中的阵列包括多个子单元，每个子单元包括多个柱状结构形成的阵列，光电转换单元的阵列分为多个颜色区域，超表面用于将入射光折射至光电转换单元的阵列中对应的颜色区域。
其中，光电转换单元的阵列可以分为多个彩色单元，每个彩色单元包括至少四个颜色区域，每个彩色单元对应超表面中的一个子单元，且每个子单元将入射光折射后传输至对应的彩色单元中的颜色区域中。
在一种可能的实施方式中，第一确定单元，具体用于若所述多个阵列中包括评价值高于预设值的至少一个阵列，则从所述评价值高于预设值的至少一个阵列中选择其中一个阵列作为所述分光滤色器件的超表面的阵列的结构；
该阵列结构构建装置，还可以包括：更新单元，用于若所述多个阵列中不包括评价值高于预设值的阵列，则更新所述多个阵列；
第二确定单元，还用于根据更新后的多个阵列确定为所述分光滤色器件的超表面的阵列的结构。
在一种可能的实施方式中，更新单元，具体用于根据所述多个评价值的值，确定所述多个阵列中每个阵列对应的变异率；根据所述每个阵列对应的变异率对所述多个阵列进行变异，得到更新后的多个阵列。
在一种可能的实施方式中，更新单元，具体用于根据所述多个评价值的值，确定所述多个阵列中每个阵列对应的概率值；根据所述每个阵列对应的概率值，对所述多个阵列进行多次采样，得到多个中间结构；根据所述多个中间结构的评价值确定所述多个中间结构的变异率；根据所述多个中间结构对应的变异率对所述多个中间结构进行变异，得到新的多个阵列。
在一种可能的实施方式中，每个彩色单元对应的颜色中至少包括两种相同的颜色，超表面中与每个彩色单元对应的区域中包括的柱状结构形成角对称的形状。
第七方面，本申请实施例提供了一种阵列结构构建装置，该阵列结构构建装置也可以称为数字处理芯片或者芯片，芯片包括处理单元和通信接口，处理单元通过通信接口获取程序指令，程序指令被处理单元执行，处理单元用于执行如上述第五方面或第五方面任一可选实施方式中与处理相关的功能。
第八方面，本申请实施例提供了一种计算机可读存储介质，包括指令，当其在计算机上运行时，使得计算机执行上述第五方面或第五方面任一可选实施方式中的方法。
第九方面，本申请实施例提供了一种包含指令的计算机程序产品，当其在计算机上运行时，使得计算机执行上述第五方面或第五方面任一可选实施方式中的方法。
附图说明
图1为本申请实施例提供的一种电子设备的结构示意图；
图2为本申请提供的一种图像传感器的结构示意图；
图3为本申请提供的一种拜耳滤色片的结构；
图4为本申请提供的另一种拜耳滤色片的结构；
图5为一个光谱通道的光信号传输的示意图；
图6为本申请提供的一种光信号的折射和反射示意图；
图7为本申请提供的一种分光滤色器件的结构示意图；
图8为本申请提供的一种图像传感器的结构示意图；
图9A为本申请提供的另一种分光滤色器件的结构示意图；
图9B为本申请提供的一种超表面的结构示意图；
图10为本申请提供的另一种图像传感器的结构示意图；
图11为本申请提供的一种光电转换单元的结构示意图；
图12为本申请提供的另一种图像传感器的结构示意图；
图13为本申请提供的另一种图像传感器件的结构示意图；
图14是本申请提供的一种阵列结构确定方法的流程示意图；
图15为本申请提供的另一种超表面的结构示意图；
图16是本申请提供的一种图像传感器的制备方法的流程示意图；
图17是本申请提供的一种图像传感器的制备方法的流程示意图；
图18是本申请提供的一种分光滤色器件的光利用率频谱示意图；
图19是本申请提供的一种光电转换单元中的光强分布示意图；
图20是本申请提供的一种阵列结构构建装置的结构示意图。
具体实施方式
下面将结合本申请实施例中的附图，对本申请实施例中的技术方案进行描述，显然，所描述的实施例仅仅是本申请一部分实施例，而不是全部的实施例。基于本申请中的实施例，本领域技术人员在没有作出创造性劳动前提下所获得的所有其他实施例，都属于本申请保护的范围。
本申请的说明书和权利要求书及上述附图中的术语“第一”、“第二”、“第三”、“第四”等(如果存在)是用于区别类似的对象，而不必用于描述特定的顺序或先后次序。应该理解这样使用的数据在适当情况下可以互换，以便这里描述的实施例能够以除了在这里图示或描述的内容以外的顺序实施。此外，术语“包括”和“具有”以及他们的任何变形，意图在于覆盖不排他的包含，例如，包含了一系列步骤或单元的过程、方法、系统、产品或设备不必限于清楚地列出的那些步骤或单元，而是可包括没有清楚地列出的或对于这些过 程、方法、产品或设备固有的其它步骤或单元。
在本申请的描述中，“多个”的含义是两个或两个以上，除非另有明确具体的限定。
在本申请中，除非另有明确的规定和限定，术语“安装”、“相连”、“连接”、“固定”、“设置”等术语应做广义理解，例如，可以是固定连接，也可以是可拆卸连接，或成一体；可以是机械连接，也可以是电连接；可以是直接相连，也可以通过中间媒介间接相连，还可以是两个元件内部的连通或两个元件的相互作用关系。对于本领域的普通技术人员而言，可以根据具体情况理解上述术语在本申请中的具体含义。
在本申请的描述中，需要理解的是，术语“长度”、“宽度”、“上”、“下”、“前”、“后”、“左”、“右”、“竖直”、“水平”、“顶”、“底”、“内”、“外”等指示的方位或位置关系为基于附图所示的方位或位置关系，仅是为了便于描述本申请和简化描述，而不是指示或暗示所指的装置或元件必须具有特定的方位、以特定的方位构造和操作，因此不能理解为对申请的限制。
在说明书及权利要求当中使用了某些词汇来指称特定的组件。本领域技术人员应可理解，硬件制造商可能会用不同的名词来称呼同一个组件。本说明书及后权利要求并不以名称的差异来作为区分组件的方式，而是以组件在功能上的差异来作为区分的准则。在说明书及权利要求当中所提及的包含或者包括是为一开放式的用语，故应解释成包含但不限定于或者包括但不限于。
为方便理解，下面先对本申请所涉及的技术术语进行解释和描述。
超材料(metamaterial)：广义定义是指人为设计的具有传统自然材料不具备的物理性质的单元结构的复合体，其物理性质主要由亚波长(远小于波长)的单元结构的结构和排列决定。
超表面(metasurface)：超材料的二维形式，本申请中的超表面包括。
焦点：光线射入超表面结构时，光线会聚在超表面结构后的几个点，会聚光线的这几个点，即为焦点。
焦距(focal length)：也称为焦长，是光学系统中衡量光的聚集或发散的度量方式。在本申请实施例中指无限远的景物通过超表面结构在焦平面结成清晰影像时，超表面结构的光学中心至焦点的距离，也可以理解为超表面结构的光学中心至焦平面的垂直距离。
下面将结合附图，对本申请中的技术方案进行描述。
本申请实施例中提供的电子设备可以包括手持设备、车载设备、可穿戴设备、计算设备或连接到无线调制解调器的其它处理设备。还可以包括数码相机(digital camera)、蜂窝电话(cellular phone)、智能手机(smart phone)、个人数字助理(personal digital assistant，PDA)电脑、平板型电脑、膝上型电脑(laptop computer)、机器类型通信(machine type communication，MTC)终端、销售终端(point of sales，POS)、车载电脑、头戴设备、穿戴设备(如手环、智能手表等)、安防设备、虚拟现实(virtual reality，VR)设备、增强现实(augmented reality，AR)设备以及其他具有成像功能的电子设备。
以数码相机为例，数码相机是数字式照相机的简称，是一种利用光电传感器把光学影像转化成数字信号的照相机。与传统相机依靠胶卷上的感光化学物质的变化来记录图像不 同，数码相机的传感器是一种光感式的电荷耦合器件(charge-coupled device，CCD)或互补金属氧化物半导体(complementary metal oxide semiconductor，CMOS)。相比于传统相机，数码相机因直接使用光电转换的图像传感器，具有更为便利，快捷，可重复，更具有及时性等优势。随着CMOS加工工艺的发展，数码相机的功能也愈发强大，已几乎全面取代传统胶片式相机，在消费电子，安防，人机交互，计算机视觉，自动驾驶等领域有着极其广泛的应用。
图1示出了本申请提供的一种电子设备的示意图，如图所示，电子设备可以包括镜头(lens)组110、图像传感器(sensor)120和电信号处理器130。电信号处理器130可以包括模数(A/D)转换器131和数字信号处理器132。其中模数转换器131即模拟信号转数字信号转换器，用于将模拟电信号转换为数字电信号。
应理解，图1中示出的电子设备并不限于包括以上器件，还可以包括更多或者更少的其他器件，例如电池、闪光灯、按键、传感器等，本申请实施例仅以安装有图像传感器120的电子设备为例进行说明，但电子设备上安装的元件并不限于此。
被摄物体反射的光信号通过镜头组110汇聚，成像在图像传感器120上。图像传感器120将光信号转换为模拟电信号。模拟电信号在电信号处理器130中通过模数(A/D)转换器131转换为数字电信号，并通过数字信号处理器132对数字电信号进行处理，例如通过一系列复杂的数学算法运算，对数据电信号进行优化，最终输出图像。电信号处理器130还可以包括模拟信号预处理器133，用于将图像传感器传输的模拟电信号进行预处理后输出至模数转换器131。
图像传感器120的性能影响最终输出的图像的质量。图像传感器120也可以称为感光芯片、感光元件等，包含有几十万到几百万的光电转换元件，受到光照射时，会产生电荷，通过模数转换器芯片转换成数字信号。
通常，图像传感器120可以通过滤色系统获取图像的颜色信息。该滤色系统可以为拜耳滤色片(Bayer color filter)系统。也就是将拜耳滤色片覆盖于图像传感器120中的光电转换元件的上方形成滤色系统。光电转换元件可以为光电二极管。拜耳滤色片也可以称为拜耳滤光片。图2示出了一种基于拜耳滤色片系统的图像传感器的示意图。该图像传感器包括微透镜121、拜耳滤色片122和光电二极管123。拜耳滤色片122中包括RGB滤色器，将RGB滤色器排列在光电二极管的方格上形成RGB马赛克式的滤色系统。仿照人眼视网膜上绿色感光细胞的数量最多的生物学特点，拜尔滤色片通常以RGGB的形式排布。基于
图3示出了基于拜耳滤色片系统的图像传感器的结构，图4示出了图像传感器中的一个彩色像素单元的结构示意图。如图3或图4所示，一个彩色像素单元包括四个滤色片122及其对应的四个光电二极管123像素元。四个滤色片122滤色片以RGGB的形式排布，即红色滤色片和蓝色滤色片处于对角线位置，两个绿色滤光片处于对角线位置。由于光电二极管123的感光区域在光电二极管像素元所占面积的中心位置，故一个彩色像素单元还包括滤色片122上方的微透镜121阵列。该微透镜121阵列用于将光信号汇聚到光电二极管123的感光区域，以保证光利用率。微透镜121阵列将入射的光信号分别汇聚至四个滤色片122上，经过四个滤色片122滤光之后，传输至各自覆盖的光电二极管123上，进而同时获得 图像的光强信息和近似的颜色信息，后期经过软件差值算法，能够优化还原出最接近真实的彩色图像。
然而，基于拜耳滤色片系统的图像传感器的光利用率很低。对于每一个颜色像素通道，也可以说是光谱通道，超过70％的光信号会被拜尔滤色片滤掉，仅有不足30％的光能够到达光电二极管，转化为电信号，用于最终的计算成像。图5示出了彩色像素单元中的一个光谱通道的光通量示意图。如图5所示，对于一个以RGGB形式排布的彩色像素单元，当入射光为白光，即含有400-700纳米所有波长的光信号，在滤色片为理想滤色效果的情况下，滤色后的光通量理论最大值仅为入射的光通量的1/3；当入射光为红光或蓝光，滤色后的光通量理论最大值为入射的光通量的1/4；当入射光为绿光，由于有两个绿色通道，滤色后的光通量理论最大值为入射的光通量的1/2。而且实际上，现实中滤色片的滤色效果不可能是完美的，即其滤色和透光效率不可能达到100％，因此实际的光利用率会更低。对于入射光为白光时的总光利用率仅有约25％；对于入射光为红光或蓝光时光利用率约为15％，当入射光为绿光时的光利用率约为30％。
或者，在一些场景中，以具有频谱分光功能的超表面替代滤色系统。根据广义斯斯涅尔定律，反射光和透射光的方向不仅取决于界面材料的折射率，还取决于界面上的相位梯度分布。例如，如图6所示，相位梯度分布可以通过公式计算，如
Figure PCTCN2020141893-appb-000001
Figure PCTCN2020141893-appb-000002
根据超表面的分光功能和广义斯涅尔定律，可计算出所需的空间相位分布，再通过各向异性的纳米鳍结构在所需波长产生所需的几何相位，即可实现频谱分光功能。然而，超表面均利用了各向异性的纳米鳍结构产生的几何相位以实现分光功能。而几何相位的一个固有特性是仅对一种圆偏振光起作用，另一种圆偏振光会会成为无用的杂光，无法被利用，因此，最多50％的光能够被利用。并且，纳米鳍结构的另一个固有特性是每一个纳米鳍结构对不同频率的光产生的几何相位是相同的，因此想要通过纳米鳍结构产生的几何相位实现对不同频率光的分光功能，只能在一个单元结构内放置不同尺寸的纳米鳍，每个尺寸的纳米鳍对不同的频带起作用，进而实现分光的效果。但是这样做势必会造成其光利用率非常低，因为不同尺寸的纳米鳍会对非对应工作频段的光起负面的散射作用。
因此，本申请提供一种应用于图像传感器的分光滤色器件，用于提高光利用率。通过集成式像素级分光器件，实现高效的像素级频谱分光功能，提高彩色图像传感器的光利用率。
下面对本申请提供的分光滤色器件、图像传感器以及图像传感器的制备方法分别进行详细说明。
首先，本申请提供一种图像传感器，该图像传感器包括分光滤色器件和光电转换单元，该分光滤色器件用于对入射光进行折射，使不同频段的光可以传输至光电转换单元中对应的颜色区域。
对本申请提供的应用于图像传感器的分光滤色器件的结构进行说明。
参阅图7，本申请提供的一种分光滤色器件的结构示意图。
该分光滤色器件包括：超表面701和衬底702。
该超表面701的阵列排列在衬底702的顶部，或者说衬底702的顶部用于承载超表面。
超表面701包括至少一个柱状结构组装成的阵列，超表面701的阵列用于对光进行折射，超表面701包括了折射率不同的两种介质。例如，可以将超表面划分为多个网格，每个网格中填充有一种介质，如二氧化钛或者空气等介质。
超表面上包括了多个子单元，每个子单元包括多个柱状结构形成的阵列。
可选地，该多个柱状结构中每个柱状结构的俯视面可以包括三角形、四边形或者六边形等中的一种，且该多个柱状结构中每个柱状结构的形状可以相同，也可以不相同。可以理解为，超表面上的每个柱状结构的俯视面的形状是可以进行无缝拼接的形状，该俯视面是朝向超表面且与超表面垂直的方向。
此外，超表面中包括了多个柱状结构形成的阵列，超表面上的每个柱状结构的俯视面的形状是可以进行无缝拼接的形状，可能因多个柱状结构相近而导致该多个柱状结构拼接成了较大的结构，如柱状结构可以是正方体结构，多个正方体可能因邻近而拼接成了长方体形状或者其他不规则形状等。
衬底702通常是光的透过率高于一定值的材料组成，如二氧化硅、聚甲基丙烯酸甲酯(polymethyl methacrylate，PMMA)或聚碳酸脂(PC)等。或者，该衬底702还可以是中空结构，以保证高透过率。
包括了分光滤色器件的图像传感器的结构可以如图8所示，衬底的底部设置于图像传感器中的光电转换单元703的表面或者顶部。光电转换单元703包括用于光电转换的阵列，光电转换单元的阵列分为多个颜色区域，超表面用于将入射光折射并经衬底传输至光电转换单元的阵列中对应的颜色区域。例如，光电转换单元中每一个像素单元可以分为四种颜色区域，如红色、绿色、绿色和蓝色(RGGB)这四个颜色区域，入射光经超表面折射后，红光经衬底传输至光电转换单元的R区域，绿光经衬底传输至G区域，蓝光经衬底传输至B区域。
其中，光电转换单元的阵列可以分为多个彩色单元(或者也可以称为像素单元或者彩色像素单元)，每个彩色单元包括至少四个颜色区域，每个彩色单元对应超表面的其中一个子单元，每个子单元对入射光进行折射并经衬底传输至对应的彩色单元中的颜色区域中。可以理解为，超表面可以理解为设置在光电转换单元的表面上方，超表面中与每个彩色单元对应的区域中包括了多个柱状结构，该多个柱状结构用于将入射的光反射至其下方的彩色单元里对应的颜色区域中。
可以理解的是，图8中所述示出的超表面701的结构即为一个子单元，光电转换单元703即可以理解为包括了四个颜色区域的一个彩色单元。该一个子单元与一个彩色单元对应，子单元用于将入射的光折射后经衬底702传输至彩色单元中对应的颜色区域中。
需要说明的是，超表面中可以包括多个子单元，每个子单元包括了多个柱状结构形成的阵列，每个子单元的阵列的结构可以相同，在确定了一个子单元的结构之后，即确定了图像传感器中的超表面的结构。当然，每个子单元的阵列的结构也可能不相同，具体可以根据实际应用场景调整。在本申请以下实施方式中，仅以其中一个子单元的结构进行示例性说明，以下不再赘述。
因此，在本申请实施方式提供分光滤色器件中，通过超表面中柱状结构形成的阵列对 不同颜色的光进行折射，当其应用于传感器中时，入射光在经超表面折射后，传输至光电转换单元中对应的颜色区域，从而实现分光。可以理解为，分光滤色器件中具有介质超表面或介质衍射表面，具有二阶二维码型的结构特征，且具有多种频谱通道，实现对多种颜色分光，实现高效分光的功能。且超表面结构上的阵列可以对入射的光进行折射，减少了散射现象，提高了光利用率。也可以理解为，超表面对入射的光实现了衍射，使不同频段的光可以传输至光电转换单元中对应的颜色区域，尤其是亚波长场景中，超表面对入射的光形成衍射，相对于拜耳滤色片和纳米鳍超表面结构，本申请提供的超表面可以对不同频段的光都实现衍射，提高光利用率。
具体地，超表面701的阵列的结构可以包括至少两折射率不同的介质构成，以两种介质为例，其中的至少一种材料可以构成柱状结构，并构成超表面的阵列。
可选地，超表面的材料包括以下一种或者多种：二氧化钛、氮化镓或碳化硅等高折射率的材料。例如，超表面的阵列可以是包括二氧化钛构成的柱状结构，多个柱状结构构成阵列，超表面中的另一种介质可以选择空气。示例性地，超表面可以由二氧化钛和空气构成，二氧化钛的折射率高于空气，超表面的结构可以如图9A所示，多个柱状结构的材料可以是二氧化钛，而另一种介质可以是空气，可以理解为二氧化钛形成的柱状结构和空气形成阵列。该阵列的俯视图可以如图9B所示，相当于可以将超表面进行网格化，划分为多个网络，每个网格的大小可以相同也可以不相同，此处以每个网格为大小相同的方形网络为例。具体例如，超表面701上的柱状结构的高度可以是500nm，每个方形网格的宽度可以是100nm，透明衬底702由二氧化硅玻璃构成，厚度为3.5um。超表面针对的传感器像素大小为800nm，即对应一个像素单元的超表面尺寸为1.6um。后续在制备分光器件时，可以通过在网格中填充介质的方式得到超表面，每种介质可以呈柱状结构，每个柱状结构的大小和形状可以相同也可以不相同。此外，其中一种介质可以是空气，另一种介质可以是与空气的折射率不同的材料。节省材料，并可以提高分光滤色器件的制备效率。
示例性地，对入射光经超表面折射后的传输方式进行示例性说明。如图10所示，图10的(a)示出了本申请实施例中一个彩色像素单元的结构示意图。如图10的(a)所示，一个彩色像素单元可以包括一个超表面701和位于该超表面结构下方的相邻的4个二维排列的光电转换元件。该4个光电转换元件分别对应图10的(b)中的光电转换元件A、光电转换元件B、光电转换元件C和光电转换元件D。这4个光电转换元件可以按照RGGB方式排列，例如，光电转换元件A、光电转换元件B、光电转换元件C和光电转换元件D可以分别对应红光、绿光、绿光和蓝光三个频段。超表面701可以红光、绿光和蓝光分别聚焦在光电转换元件A、光电转换元件B、光电转换元件C和光电转换元件D的感光位置上。结合前述图6所示的界面上的空间传输相位梯度为0的情况下折射光和反射光的传输路径和界面上的空间传输相位梯度不为0的情况下折射光和反射光的传输路径。在超表面701的阵列的切线方向产生空间传输相位，以得到空间传输相位梯度，空间传输相位梯度用于将所述每个频段的光信号传输至每个频段对应的光电转换元件。在本申请实施例中，传输相位也可以称为透射相位。
空间传输相位梯度的存在使得入射的光信号与超表面701能够形成一定的共振效应， 当不同频段的光信号经过超表面701时，会在超表面701中上产生不同的传输相位变化，进而能够改变光信号的折射角，也就是控制光信号的传播方向，将不同频段的光信号传输至不同频段的光电转换元件。
应理解，上述频谱波段的数值仅作为解释参考数据，不应视为对本申请实施例的限制，具体的每个频谱通道频率范围以实际图像传感器整体的频谱设计和光电转换元件的实际频谱响应范围为准。图10中示出的一个彩色像素单元中的光电转换元件的数量仅为示意，不构成对本申请实施例的限制。
在一种可能的实施方式中，每个彩色单元对应的颜色中至少包括两种相同的颜色，每个彩色单元上方的超表面的区域中包括的柱状结构的表面形成角对称的形状。
例如，光电转换单元中每四个形成矩阵排列的像元对应的颜色可以是按照RGGB的方式排列，如左上角和右上角的颜色区域对应的颜色为绿色，其他两个角对应的颜色为红色和蓝色，与之对应的，如前述图7-图9B所示出的超表面的结构，超表面上的结构组成的阵列的俯视图可以是对称的结构，以使入射光可以经超表面的结构折射传输到光电转换单元中对应的颜色区域中。
图11示出了一种光电转换单元220的阵列的示意图。如图11所示，每个光电转换单元703可以对应4个光电转换元件，4个光电转换元件按照RGGB方式排列。此外，光电转换单元中还可以设置抗发射板，用于减少光电转换单元对光信号的反射，进一步提高光利用率。
应理解，图10和图11中示出的一个光电转换单元703中的光电转换元件的数量仅为示意，实际中光电转换元件的数量还可以是更多或者更少，此处提及的4个光电转换元件不构成对本申请实施例的限制。
因此，在本申请实施方式中，通过在分光滤色器件的超表面设置柱状结构构成的阵列，实现对不同频段的光的折射。相对于传统的拜耳滤色片，本申请通过对不同频段的光进行折射，使各个频段的光传输至光电转换单元中对应的区域，避免了因滤色片的过滤而导致的光利用率低。
通常，通过纳米鳍结构来对光进行折射，仅对一种圆偏振光起作用，另一种圆偏振光会会成为无用的杂光，无法被利用，因此，大大降低了光利用率。而本申请提供的分光滤色器件，对所有入射偏振的光可以进行折射，而不仅仅是其中一种圆偏振光起作用，对偏振的依赖性小，因此，本申请提供的分光滤色器件可以极大提高光利用率。
此外，通过纳米鳍结构来对光进行折射，因每一个纳米鳍结构对不同频率的光产生的几何相位是相同的，因此想要通过纳米鳍结构产生的几何相位实现对不同频率光的分光功能，只能在一个单元结构内放置不同尺寸的纳米鳍，每个尺寸的纳米鳍对不同的频带起作用，进而实现分光的效果。但是这样做势必会造成其光利用率非常低，因为不同尺寸的纳米鳍会对非对应工作频段的光起负面的散射作用。而本申请实施方式中，超表面的阵列结构可以由折射率不同的至少两种介质构成，柱状结构对不同频段的光都有所需的响应，而避免了因不同尺寸的纳米鳍折射不同频段的光而导致的不被折射的光的利用率低的问题，进一步提高了光利用率。
可选地，光电转换单元的表面还可以包括抗反射层或者在光电转换单元的表面与衬底之间设置抗反射层，以减少对入射光的反射，提高光利用率。
在一种可能的实施方式中，光电转换单元703和衬底702之间还设置有滤色结构，滤色结构分为多个滤色区域，且每个滤色区域覆盖一个对应的颜色区域，且每个颜色区域对应的颜色与每个颜色区域上覆盖的滤色区域透过的颜色相同。例如，该滤色结构可以四滤色片或者其他透过指定频段的介质等。
示例性地，如图12所示，可以在光电转换单元与衬底之间设置滤色片704，该滤色片可以分为多个滤色区域，用于对除特定频段的光之外的光进行过滤。例如，若该滤色片对应的颜色区域为绿色，则该滤色片可以透过绿色，并对除绿色之外的其他颜色进行过滤。
因此，在本申请实施方式中，可以通过增加滤色结构，对传输至光电转换单元中的每个颜色区域的光进行过滤，滤除不在特定频段的光，从而避免对光电转换单元对光信号进行转换的干扰，进一步提高光利用率。
在一种可能的实施方式中，每个滤色区域与衬底之间还设置有透镜。
示例性地，如图13所示，在每个滤色区域与衬底之间设置微型凸透镜705(简称微透镜)。通常，每个微透镜的大小与其覆盖的滤色区域的大小相同，从而使传输至滤色区域的光进行汇聚，以减少向颜色区域传输的光的散射，进一步提高光利用率。因此，本申请实施方式中，分光滤色器件中可以配合滤色片和微透镜，降低每个通道的串扰。
在一种可能的实施方式中，多个颜色区域对应的颜色多个频段的光，包括：绿色、红色、蓝色或者红外光(infrared radiation，IR)中的一种或者多种。
例如，本申请提供的分光滤色器件的分光频谱通道数量不小于两个，频谱的频段范围在紫外到近红外范围内，取决于图像传感器的用途和感光层的频谱响应范围；频谱数量和通道排布取决于图像传感器用途；例如，用于可见光成像，频谱频段范围为400-700nm可见光范围，频谱数量为3，通道排布为RGGB；用于多光谱成像，平铺频段范围为400-700，频谱数量可以为7；用于可见光&近红外成像，频谱频段范围则为400-1000nm，频谱数量为4，通道排布可以为RGB&IR。因此，在本申请实施方式中，可以实现对多种可见光或者不可见光的分光，适应多种场景，泛化能力强。
前述对本申请提供的分光滤色器件的结构进行了示例性说明，由上述结构可知，分光滤色器件的超表面对提高光利用率起着重要作用，而超表面的阵列的排列方式可以有多种，下面对确定该分光滤色器件的超表面的阵列结构的方法进行介绍。
参阅图14，本申请提供一种应用于图像传感器的阵列结构确定方法，该图像传感器包括分光滤色器件和光电转换单元，分光滤色器件可以参阅前述图7-图13中的分光滤色器件，此处不再赘述，下面对本申请提供的应用于图像传感器的阵列结构确定方法的详细步骤进行介绍。
1401、确定多个阵列的结构。
其中，该多个阵列的结构可以是从预先设定的搜索空间中搜索得到的，也可以是随机生成的结构。每个阵列可以是网格化的结构，也可以是蜂窝结构等。每个结构的高度可以相同也可以不相同。每个结构的高度也可以在预先设定的搜索空间中搜索得到。可以理解 为，可以在搜索空间中，预先设定不同的阵列结构，和高度的取值范围，然后从该搜索空间中采样得到多个阵列结构以及每个阵列结构对应的高度。
例如，可以预先生成多种阵列结构，构成搜索空间，然后可以根据实际应用场景来筛选可用的阵列结构，从而快速得到多种阵列，提高得到多个阵列的效率。又例如，可以随机生成一种或者多种二维码图像，然后根据该多种二维码图像构建得到个阵列。具体例如，可以预先设定待构建的超表面的尺寸，然后将该超表面进行网格化，划分为方形网格或者六边形网格等，然后随机对每个网格进行填充，得到阵列结构，如图15所示。
1402、通过评价函数对多个阵列的结构进行评估，得到与多个阵列中每个阵列对应的评价值。
其中，评价函数为计算多个阵列作为分光滤色器件的超表面时分光滤色器件的光利用率的函数，得到每个阵列的光利用率，然后根据评价值确定分光滤色器件的超表面的阵列的结构。
例如，可以随机生成N个初始的二维码结构，每个二维码结构由N*N的方形区域构成，每个区域可以是两种介质材料中的一种，如空气和二氧化钛，即可组成N*N的0/1组成的二阶矩阵表征该结构。结构高度在1um以内的一个随机高度。本实施例中1代表二氧化钛，0代表空气。根据RGGB的分光功能建立仿真模型，通过仿真求解麦克斯韦方程，计算得出平均光利用率，作为评价函数如下：
Figure PCTCN2020141893-appb-000003
其中λ r1～λ r2，λ g 1～λ g2，λ b1～λ b2分别为红光、绿光、蓝光的光谱，T r,T g,T b分别为红光、绿光、和蓝光对应的像元区域的透过率。具体例如，可以通过仿真生成N个二维码结构对应的图像传感器，然后通过评价函数计算每个仿真的图像传感器的光利用率，得到每个阵列对应的光利用率。当然，也可以通过制备每个阵列对应的图像传感器来计算光利用率，本申请对此并不作限定。
1403、判断多个阵列中包括评价值高于预设值的至少一个阵列，若是，则执行步骤1404，若否，则执行步骤1405。
在得到多个阵列中每个阵列的评价值之后，判断该多个阵列中是否有评价值高于预设值的阵列，若多个阵列中包括评价值高于预设值的至少一个阵列，则可以从评价值高于预设值的阵列中选择其中一个阵列作为分光滤色器件的超表面的阵列的结构；若多个阵列中不包括评价值高于预设值的阵列，则可以得到新的阵列，直到得到评价值高于预设值的阵列。
1404、从评价值高于预设值的至少一个阵列中选择其中一个阵列作为分光滤色器件的超表面的结构。
其中，可以从评价值高于预设值的一个或者多个阵列中选择一个作为前述的分光滤色器件的超表面的结构。
例如，若存在多个阵列的评价值高于50％，则可以从该多个评价值高于50％的阵列中选择评价值最高的阵列作为分光滤色器件的超表面的结构。或者，从该多个评价值高于50％的阵列中随机选择一个阵列作为分光滤色器件的超表面的结构等。
1405、更新多个阵列。
其中，若多个阵列中不存在评价值高于预设值的阵列，则更新该多个阵列，并根据更新后的多个阵列确定分光滤色器件的超表面的结构，即重复执行步骤1402-1403，直到得到评价值高于预设值的阵列。
其中，更新该多个阵列的方式可以包括多种，下面对一些可能的实施方式进行介绍。
在一种可能的实施方式中，可以根据多个评价值的值，确定多个阵列中每个阵列对应的变异率，该变异率具体可以包括形状变异率或高度变异率等，形状变异率即对阵列结构的形状进行变异的概率或者比例等，高度变异率即对阵列的高度进行变异的概率或者比例等；然后，根据每个阵列对应的变异率对多个阵列进行变异，得到更新后的多个阵列，具体可以是基于形状变异率对多个阵列的形状进行变异，或者基于高度变异率对多个阵列的高度进行变异等。通常，每个阵列的评价值可以用于表示每个阵列通过仿真代入图像传感器后得到光利用率，光利用率越高，对应的变异率也就越低，光利用率和变异率之间的关系可以是线性关系，也可以是指数关系等，具体可以根据实际应用场景调整。而变异率越高，则表示对阵列进行变异的比例也更大。例如，若形状变异率为20％，则可以对阵列中的20％的区域进行变异，得到变异后的阵列。具体的变异方式可以是对阵列中的部分区域中的柱状结构进行重新排列，与其他阵列中的部分区域的结构进行交换等，具体的变异方式可以根据实际应用场景进行调整。若高度变异率为10％，则对阵列的高度增加或减少10％，得到的变异后的高度。具体的变异方式可以根据实际应用场景进行调整。
因此，在本申请实施方式中，可以基于每个阵列的评价值确定每个阵列的形状和高度变异率，从而完成对阵列的变异，评价值越高的阵列对应的变异率越低，从而通过调整阵列的结构，使新的阵列的结构更接近预设值，以便后续筛选出光利用率更高的阵列。
在另一种可能的实施方式中，可以根据多个评价值的值，确定多个阵列中每个阵列对应的概率值；然后，根据每个阵列对应的概率值，对多个阵列进行采样，得到多个中间结构；随后，根据多个中间结构的评价值确定多个中间结构的变异率，包括形状变异率或高度变异率等；随后，根据多个中间结构对应的变异率对多个中间结构进行变异，得到新的多个阵列。具体的变异方式可以是对阵列中的部分区域中的柱状结构进行重新排列，与其他阵列中的部分区域的结构进行交换等，具体的变异方式可以根据实际应用场景进行调整。
例如，若阵列1对应的光利用率为25％，阵列2对应的光利用率为30％，阵列3的光利用率为26％等等，然后基于每个阵列的光利用率的值，为每个阵列设置被采样的概率，如阵列1的概率为10，阵列2的概率为25％，阵列3的概率为13％等等，然后可以基于每个阵列的概率进行一次或者多次采样，得到多个这列，即多个中间结构。具体例如，为每个阵列设置对应的概率的方式可以包括：
Figure PCTCN2020141893-appb-000004
其中i代表第i个二维码结构，F i为第i个结构的评价函数,n可取大于等于1的整数。
其中，若进行了多次采样，每次采样可以基于每个阵列的概率进行采样，不同批次的采样可能采样出的阵列可能相同也可能不相同。因此，在本申请实施方式中，可以基于每个阵列的光利用率设定每个阵列的概率，从而后续在进行采样时，光利用率越高的阵列，被采样的概率也就越大，并对采样得到的阵列进行变异，从而得到新的阵列。
在另一种可能的实施方式中，若预先设置了搜索空间，则若未筛选出评价值高于预设值的阵列，则可以重新从搜索空间中搜索得到多个阵列。
在本申请提供的方法中，可以基于设定的光利用率的需求目标，通过遗传算法、模拟退火算法或者梯度下降等优化算法，来逆向得到符合光利用率的需求目标的阵列，从而提高分光滤色器件和图像传感器的光利用率。
前述对本申请提供的分光滤色器件、图像传感器和应用与图像传感器的阵列结构确定方法进行了详细介绍，下面基于前述的分光滤色器件、图像传感器和应用与图像传感器的阵列结构确定方法，对本申请提供的图像传感器的制备方法进行详细介绍。
参阅图16，本申请提供的一种图像传感器的制备方法的流程示意图，如下所述。
1601、制备光电转换单元，光电转换单元用于将光信号转换为电信号，光电转换单元包括用于光电转换的阵列，光电转换单元的阵列分为多个颜色区域。
1602、在光电转换单元的表面制备分光滤色器件。
其中，分光滤色器件包括超表面和衬底，超表面中的阵列排列在衬底的顶部，衬底的底部设置于光电转换单元的表面或者顶部，超表面包括多个子单元，每个子单元包括多个柱状结构形成的阵列，且超表面包括折射率不同的至少两种介质，光电转换单元包括用于光电转换的阵列，光电转换单元的阵列分为多个颜色区域，超表面用于将入射光折射至光电转换单元的阵列中对应的颜色区域。
其中，光电转换单元的阵列可以分为多个彩色单元，每个彩色单元包括至少四个颜色区域，超表面中的每个子单元对应一个彩色单元，且每个子单元将入射光折射后传输至对应的彩色单元中的颜色区域中。通常，每个子单元中的阵列的结构可以相同，也可以不相同。
例如，可以采用CMOS工艺集成加工光电转换单元的阵列和超表面结构的阵列。具体例如，超表面可以包括由二氧化钛和空气这两种介质构成的阵列，在确定超表面的阵列结构之后，可以在阵列中填充二氧化钛构成的柱状结构。
示例性地，步骤1602可以包括：在光电转换单元的阵列上沉积衬底，在衬底上制备微结构。
因此，在本申请实施方式中，可以在光电转换单元表面制备衬底，并在衬底顶部制备超表面的阵列，通过超表面中柱状结构形成的阵列对不同颜色的光进行折射，入射光在经超表面折射后，传输至光电转换单元中对应的颜色区域，从而实现分光。可以理解为，分光滤色器件中具有介质超表面或介质衍射表面，具有二阶二维码型的结构特征，且具有多种频谱通道，实现对多种颜色分光，实现高效分光的功能。且超表面结构上的阵列可以对入射的光进行折射，减少了散射现象，提高了图像传感器的光利用率。
在一种可能的实施方式中，还可以在光电转换单元和衬底之间制备滤色结构，滤色结构分为多个滤色区域，且每个滤色区域覆盖一个对应的颜色区域，且每个颜色区域对应的颜色与每个颜色区域上覆盖的滤色区域透过的颜色相同，每个滤色区域用于过滤除所覆盖颜色区域对应的颜色之外的颜色的光。
在一种可能的实施方式中，还可以在每个滤色区域与衬底之间制备透镜。
在一种可能的实施方式中，多个颜色区域对应的颜色多个频段的光，包括：绿色、红色、蓝色或者红外光中的一种或者多种。
在一种可能的实施方式中，超表面的材料包括以下一种或者多种：二氧化钛、氮化镓或碳化硅。
在一种可能的实施方式中，每个彩色单元对应的颜色中至少包括两种相同的颜色，每个彩色单元上方的超表面的区域中包括的柱状结构的表面形成角对称的形状。
此外，在制备超表面之前，还可以构建超表面的阵列结构。示例性地，参阅图17，下面结合构建超表面的阵列结构的方法，对本申请提供的图像传感器的制备方法的流程进行更详细的介绍，如下所述。
1701、确定多个阵列的结构。
1702、通过评价函数对多个阵列的结构进行评估，得到与多个阵列中每个阵列对应的评价值。
1703、判断多个阵列中包括评价值高于预设值的至少一个阵列，若是，则执行步骤1705，若否，则执行步骤1704。
1704、更新多个阵列。
1705、从评价值高于预设值的至少一个阵列中选择其中一个阵列作为分光滤色器件的超表面的结构。
其中，步骤1701-1705可以参阅前述步骤1401-1405，此处不再赘述。
1706、制备光电转换单元。
1707、在光电转换单元的表面制备分光滤色器件。
其中，步骤1706-1707可以参阅前述步骤1601-1602，此处不再赘述。
因此，在本申请实施方式中，在制备超表面之前，还可以确定超表面的阵列结构，从而得到光利用率更高的图像传感器。可以理解为，可以基于设定的光利用率的需求目标，通过遗传算法、模拟退火算法或者梯度下降等优化算法，来逆向得到符合光利用率的需求目标的阵列，从而提高分光滤色器件和图像传感器的光利用率。
下面以更具体的应用场景对本申请所提及的图像传感器的光利用率进行更详细地介绍。
示例性地，图18是400-700nm可见光波段范围该分光器件的光利用率频谱图，横坐标为波长，纵坐标为透过率。Tb表示到达右下角蓝色感光像素元的光透过率，Tg和Tg2分别表示到达右上角和左下角两个感光像素元的光透过率，Tr表示到达左上角红色感光像素元的透过率。如图18所示，本实施例使可见光的光利用率提高至55.9％，约为传统滤色片光利用率的224％。其中红光光利用率为73.7％，约为传统滤色片光利用率的393％；绿光光利用率为47.9％，约为传统滤色片光利用率的127％；蓝光光利用率为47.3％，约为传统滤色片光利用率的252％。
距离介质分光器件层底部3.5um平面上的光强分布如图19所示，(a)(b)(c)分别对应波长分别为450nm，536nm和640nm，可看出红绿蓝三色光分别按照RGGB的排布方式被分别聚焦于右下、左下、右上和左上4个感光像素元位置，频谱串扰通过增加滤色片层消除，散射光较少。
显然，通过上述分析可知，本申请提供的图像传感器的光利用率显然高于拜耳滤色片或者纳米鳍结构的光利用率。因此，本申请实施方式相对于通过滤色方法获取颜色信息的拜尔滤色片，本申请利用像素级频谱分光器件通过频谱分光突破单一滤色系统的光利用率理论限制，原理性提高彩色图像传感器的光利用率。对于纳米鳍结构的超表面技术，本发明利用功能驱动的逆向设计算法设计二阶二维码型结构，具有分光效率高，偏振依赖性小，匹配感光像素元更小的优势。此外，通过提高图像传感器的光利用率，提高使用该图像传感器进行拍摄时的信噪比，提高在弱光条件下拍摄的图像质量，提高弱光条件下的拍照性能。
参阅图20，本申请还提供一种阵列结构构建装置，用于执行前述图14的方法，该装置可以包括：
第一确定单元2001，用于确定多个阵列的结构；
评价单元2002，用于通过评价函数对所述多个阵列的结构进行评估，得到与所述多个阵列中每个阵列对应的评价值，所述评价函数为计算所述多个阵列作为所述分光滤色器件的超表面时所述分光滤色器件的光利用率的函数；
第二确定单元2003，用于根据所述评价值确定所述分光滤色器件的超表面的结构，该分光滤色器件包括于图像传感器中，图像传感器包括分光滤色器件和光电转换单元，分光滤色器件包括超表面和衬底，光电转换单元包括用于光电转换的阵列，分光滤色器件包括超表面和衬底，超表面中的阵列排列在衬底的顶部，衬底的底部设置于光电转换单元的表面或者顶部，超表面包括折射率不同的至少两种介质构成的阵列，超表面中的阵列包括至少一个柱状结构形成的阵列，光电转换单元的阵列分为多个颜色区域，超表面用于将入射光折射至光电转换单元的阵列中对应的颜色区域。
其中，光电转换单元的阵列可以分为多个彩色单元，每个彩色单元包括至少四个颜色区域，每个彩色单元对应一个子单元，且每个子单元将入射光折射后传输至对应的彩色单元中的颜色区域中。
在一种可能的实施方式中，第一确定单元2001，具体用于若所述多个阵列中包括评价值高于预设值的至少一个阵列，则从所述评价值高于预设值的至少一个阵列中选择其中一个阵列作为所述分光滤色器件的超表面的阵列的结构；
该阵列结构构建装置，还可以包括：更新单元2004，用于若所述多个阵列中不包括评价值高于预设值的阵列，则更新所述多个阵列；
第二确定单元，还用于根据更新后的多个阵列确定为所述分光滤色器件的超表面的阵列的结构。
在一种可能的实施方式中，更新单元2004，具体用于根据所述多个评价值的值，确定所述多个阵列中每个阵列对应的变异率；根据所述每个阵列对应的变异率对所述多个阵列进行变异，得到更新后的多个阵列。
在一种可能的实施方式中，更新单元2004，具体用于根据所述多个评价值的值，确定所述多个阵列中每个阵列对应的概率值；根据所述每个阵列对应的概率值，对所述多个阵列进行多次采样，得到多个中间结构；根据所述多个中间结构的评价值确定所述多个中间 结构的变异率；根据所述多个中间结构对应的变异率对所述多个中间结构进行变异，得到新的多个阵列。
在一种可能的实施方式中，每个彩色单元对应的颜色中至少包括两种相同的颜色，每个彩色单元上方的超表面的区域中包括的柱状结构的表面形成角对称的形状。
因此，每至少四个排列成矩阵的颜色区域可以对应至少两种相同的颜色，对称的两种颜色区域对应的颜色可能相同，本实施例提供了一种适用于超表面的阵列的可能的排列方式。
以上所述仅为本申请的可选实施例，并不用以限制本申请，凡在本申请的精神和原则之内，所作的任何修改、等同替换、改进等，均应包含在本申请的保护范围之内。

Claims (22)

  1. 一种图像传感器，其特征在于，包括：超表面、衬底和光电转换单元；
    所述超表面包括多个子单元，每个子单元包括多个柱状结构形成的阵列，所述超表面中的阵列排列在所述衬底的顶部，所述衬底的底部设置于所述光电转换单元的表面，所述超表面包括折射率不同的至少两种介质，所述光电转换单元包括用于光电转换的阵列，所述光电转换单元的阵列分为多个彩色单元，每个彩色单元包括至少四个颜色区域，每个彩色单元对应所述多个子单元中的其一个子单元，所述超表面用于将入射光折射并经所述衬底传输至所述光电转换单元的阵列中对应的颜色区域，且所述每个子单元对入射光折射后经所述衬底传输至对应的彩色单元中的颜色区域。
  2. 根据权利要求1所述的图像传感器，其特征在于，
    所述光电转换单元和所述衬底之间还设置有滤色结构，所述滤色结构分为多个滤色区域，且每个滤色区域覆盖一个对应的颜色区域，且所述每个颜色区域对应的颜色与所述每个颜色区域上覆盖的滤色区域透过的颜色相同。
  3. 根据权利要求2所述的图像传感器，其特征在于，所述每个滤色区域与所述衬底之间还设置有透镜。
  4. 根据权利要求1-3中任一项所述的图像传感器，其特征在于，所述多个颜色区域对应的多个频段的光，包括：绿色、红色、蓝色或者红外光中的一种或者多种。
  5. 根据权利要求1-4中任一项所述的图像传感器，其特征在于，所述超表面的材料包括以下一种或者多种：二氧化钛、氮化镓或碳化硅。
  6. 根据权利要求1-5中任一项所述的图像传感器，其特征在于，所述每个彩色单元对应的颜色中至少包括两种相同的颜色，与所述每个彩色单元对应的所述子单元中包括的多个柱状结构形成角对称的形状。
  7. 一种分光滤色器件，其特征在于，包括：超表面和衬底；
    所述超表面包括多个子单元，每个子单元包括多个柱状结构形成的阵列，所述超表面中的阵列排列在所述衬底的顶部，所述超表面包括折射率不同的至少两种介质，所述超表面用于将对入射光产生折射，所述衬底用于传输经所述超表面折射后的光。
  8. 根据权利要求7所述的分光滤色器件，其特征在于，所述分光滤色器件应用于图像传感器，所述图像传感器中包括光电转换单元，所述衬底设置于所述光电转换单元的表面，所述光电转换单元包括用于光电转换的阵列，所述光电转换单元的阵列分为多个彩色单元，每个彩色单元包括至少四个颜色区域，每个彩色单元对应所述多个子单元中的其一个子单元，所述超表面将入射光折射并经所述衬底传输至所述光电转换单元的阵列中对应的颜色区域，且所述每个子单元将入射光折射并传输至对应的彩色单元中的颜色区域。
  9. 根据权利要求8所述的分光滤色器件，其特征在于，所述每个彩色单元对应的颜色中至少包括两种相同的颜色，所述超表面中与所述每个彩色单元对应的区域包括的柱状结构形成角对称的形状。
  10. 根据权利要求7-9中任一项所述的分光滤色器件，其特征在于，
    所述光电转换单元和所述衬底之间还设置有滤色结构，所述滤色结构分为多个滤色区域，且每个滤色区域覆盖一个对应的颜色区域，且所述每个颜色区域对应的颜色与所述每个颜色区域上覆盖的滤色区域透过的颜色相同。
  11. 一种图像传感器的制备方法，其特征在于，包括：
    制备光电转换单元，所述光电转换单元用于将光信号转换为电信号，所述光电转换单元包括用于光电转换的阵列，所述光电转换单元的阵列分为多个颜色区域；
    在所述光电转换单元的表面制备分光滤色器件，所述分光滤色器件包括超表面和衬底，所述超表面包括多个子单元，每个子单元包括多个柱状结构形成的阵列，所述超表面中的阵列排列在所述衬底的顶部，所述衬底的底部设置于所述光电转换单元的表面，所述超表面包括折射率不同的至少两种介质，所述光电转换单元的表面为接收光信号的面，所述光电转换单元的阵列分为多个彩色单元，每个彩色单元包括至少四个颜色区域，每个彩色单元对应所述多个子单元中的其一个子单元，所述超表面用于将入射光折射至所述光电转换单元的阵列中对应的颜色区域，且所述每个子单元将入射光折射后经所述衬底传输至对应的彩色单元中的颜色区域。
  12. 根据权利要求11所述的方法，其特征在于，在所述光电转换单元的表面制备分光滤色器件之前，所述方法还包括：
    确定多个阵列，并将所述多个阵列作为所述分光滤色器件的超表面的结构，得到多种分光结构；
    通过预设的评价函数得到与所述多种分光结构一一对应的多个评价值，所述评价函数为计算所述分光结构的光利用率的函数；
    若所述多个评价值中包括高于预设值的至少一个评价值，则从所述多种分光结构中筛选出第一分光结构作为所述分光滤色器件的结构，所述第一分光结构的评价值高于所述预设值。
  13. 根据权利要求12所述的方法，其特征在于，所述方法还包括：
    若所述多个评价值中不包括高于预设值的至少一个评价值，则重新确定多个阵列，并根据重新确定的多个阵列确定分光结构作为所述分光滤色器件的结构。
  14. 根据权利要求13所述的方法，其特征在于，所述重新确定多个阵列，包括：
    根据所述多个评价值的值，确定所述多个阵列中每个阵列对应的变异率；
    根据所述每个阵列对应的变异率对所述多个阵列进行变异，得到更新后的多个阵列。
  15. 根据权利要求14所述的方法，其特征在于，所述每个阵列对应的变异率包括形状变异率和/或高度变异率，所述形状变异率包括对所述每个阵列的形状进行变异的概率或者比例，所述高度变异率包括对所述每个阵列的高度进行变异的概率或者比例。
  16. 根据权利要求13所述的方法，其特征在于，所述重新确定多个阵列，包括：
    根据所述多个评价值的值，确定所述多个阵列中每个阵列对应的概率值；
    根据所述每个阵列对应的概率值，对所述多个阵列进行多次采样，得到多个中间结构；
    根据所述多个中间结构的评价值确定所述多个中间结构的变异率；
    根据所述多个中间结构对应的变异率对所述多个中间结构进行变异，得到新的多个阵列。
  17. 根据权利要求11-16中任一项所述的方法，其特征在于，所述方法还包括：
    在所述光电转换单元和所述衬底之间制备滤色结构，所述滤色结构分为多个滤色区域，且每个滤色区域覆盖一个对应的颜色区域，且所述每个颜色区域对应的颜色与所述每个颜色区域上覆盖的滤色区域透过的颜色相同，所述每个滤色区域用于过滤除所覆盖颜色区域对应的颜色之外的颜色的光。
  18. 根据权利要求17所述的方法，其特征在于，所述方法还包括：
    在所述每个滤色区域与所述衬底之间制备透镜。
  19. 根据权利要求11-18中任一项所述的方法，其特征在于，所述多个颜色区域对应的多个频段的光，包括：绿色、红色、蓝色或者红外光中的一种或者多种。
  20. 根据权利要求11-19中任一项所述的方法，其特征在于，所述超表面的材料包括以下一种或者多种：二氧化钛、氮化镓或碳化硅。
  21. 根据权利要求11-20中任一项所述的方法，其特征在于，所述每个彩色单元对应的颜色中至少包括两种相同的颜色，所述超表面中与所述每个彩色单元对应的区域包括的柱状结构形成角对称的形状。
  22. 一种电子设备，其特征在于，所述电子设备包括如权利要求1-6中任一项所述的图像传感器。
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