Pixel polarizer array, design method thereof and polarization imaging device

Abstract

The invention provides a pixel polaroid array and a design method thereof and a polarization imaging device, and relates to the technical field of optics, the pixel polaroid array comprises a substrate and a metal nano grating array, the metal nano grating array is arranged on the upper surface of the substrate, the substrate is used for supporting the metal nano grating array, and the metal nano grating array is arranged on the upper surface of the substrate. The metal nano grating array is composed of a plurality of polarization units which are periodically arranged; the polarization unit is composed of a plurality of polarization subunits arranged in the polarization direction. The polarization subunit is composed of a nano grating array; the line width of the nano grating array in the 0-degree polarization subunit is equal to the line width of the nano grating array in the 90-degree polarization subunit, the line width of the nano grating array in the 45-degree polarization subunit is equal to the line width of the nano grating array in the 135-degree polarization subunit, and the size of the polarization subunits is the same as the pixel size of the integrated image sensor. According to the pixelated design method, the overall extinction ratio and uniformity of the pixel polaroid array are improved.

Description

Technical Field

[0001] The present invention relates to the field of optical technologies, and in particular, to a pixel polarizer array, a design method thereof, and a polarization imaging device. Background Art

[0002] Conventional imaging technologies perform imaging by acquiring information such as the light intensity and wavelength of light. It is difficult to distinguish the target object when the light intensity of the target object is similar to that of the background light. In addition to being able to acquire light intensity and wavelength information, polarization imaging technology can also acquire additional dimensional information - polarization information for image enhancement imaging. It can not only achieve efficient recognition of target objects under conventional imaging conditions, but also achieve effective recognition of target objects under low-light or occlusion conditions. Therefore, this unique advantage enables polarization imaging technology to have broad application prospects and great potential in fields such as industrial inspection, medical detection, and military target recognition.

[0003] The rapid development of micro-nano processing technology has made sub-focal plane polarization imaging technology possible. In recent years, polarization cameras prepared by using a pixel polarizer array and its integration with a camera have achieved polarization imaging in the infrared and visible light bands. The sub-focal plane polarization imaging technology mainly consists of a pixel polarization camera hardware part and an imaging algorithm software. Among them, the pixel polarization camera hardware is mainly obtained by corresponding the pixel units of a 2×2 unit "superpixel" polarizer array of nano gratings in four directions of 0°, 45°, 90°, and 135° to the pixels of the image sensor one by one and performing integrated preparation; the imaging software is often related to algorithms, and the imaging effects of different algorithms are different. Different from the polarization camera based on a single polarization direction, which can only acquire polarization information in a single direction in one imaging, the pixel polarization camera can acquire polarization information in 4 directions simultaneously in one image acquisition. Then, using relevant algorithms, the corresponding polarization degree image and polarization angle image can be obtained in real time. This imaging technology not only has advantages such as a compact hardware structure, small volume, and strong environmental adaptability, but also can further improve the image quality or obtain more important information of the target object by developing advanced algorithms and imaging conditions. It is the main development direction of polarization imaging technology.

[0004] Currently, the pixels in different directions of the pixel polarizer arrays used in existing polarization cameras or commercial products all adopt a metal grating structure with the same period and line width. In fact, although the widths of the nano gratings in the two directions of 45° and 135° are the same as those in the 0° and 90° directions, due to the difference in the lengths of the nano gratings, it will cause deterioration of the extinction characteristics and performance reduction of the pixelated polarizer, resulting in uneven extinction ratios of the pixel polarizers in different directions, which will seriously affect the polarization imaging quality and polarization measurement accuracy. Therefore, how to design a pixel polarizer to ensure a uniform extinction ratio is an urgent problem to be solved. Summary of the Invention

[0005] The present invention provides a pixel polarizer array, a design method thereof, and a polarization imaging device, which are used to solve the problem of how to design a pixel polarizer to ensure uniform extinction ratio.

[0006] In a first aspect, the present invention provides a pixel polarizer array, including: a substrate and a metal nano-grating array, wherein the metal nano-grating array is disposed on the upper surface of the substrate, the substrate is used to support the metal nano-grating array, and the metal nano-grating array is composed of a plurality of polarization units arranged periodically; the polarization unit is composed of a plurality of polarizer sub-units arranged in a polarization direction; the polarizer sub-unit is composed of nano-grating arrays with polarization directions of 0°, 45°, 90°, and 135°; the line width of the nano-grating array in the 0° polarizer sub-unit is equal to the line width of the nano-grating array in the 90° polarizer sub-unit, and the line width of the nano-grating array in the 45° polarizer sub-unit is equal to the line width of the nano-grating array in the 135° polarizer sub-unit; the size of the polarization unit is the same as the pixel size of the integrated image sensor.

[0007] According to the pixel polarizer array provided by the present invention, the extinction ratio of the nano-grating array in the 0° polarizer sub-unit, the extinction ratio of the nano-grating array in the 90° polarizer sub-unit, the extinction ratio of the nano-grating array in the 45° polarizer sub-unit, and the extinction ratio of the nano-grating array in the 135° polarizer sub-unit are equal.

[0008] According to the pixel polarizer array provided by the present invention, it further includes: an opaque anti-crosstalk region, which is disposed between adjacent polarizer sub-units, and the opaque anti-crosstalk region is used to block signal crosstalk between the adjacent polarizer sub-units.

[0009] According to the pixel polarizer array provided by the present invention, the width of the anti-crosstalk region is less than the size of the polarizer sub-unit, and the height of the anti-crosstalk region is the same as the height of the pixel polarizer array.

[0010] According to the pixel polarizer array provided by the present invention, the line width of the nano-grating array in the 0° polarizer sub-unit is less than the line width of the nano-grating array in the 45° polarizer sub-unit; the line width of the nano-grating array in the 90° polarizer sub-unit is less than the line width of the nano-grating array in the 135° polarizer sub-unit.

[0011] According to the pixel polarizer array provided by the present invention, the period and height of the nano-grating array in the polarization unit are the same.

[0012] According to a pixel polarizer array provided by the present invention, the material of the substrate is any one of transparent materials, the material of the nano-grating array is any one of metal materials, and the material of the anti-crosstalk region is any one of metal materials.

[0013] In a second aspect, the present invention also provides a method for designing a pixel polarizer array, which is applied to the above pixel polarizer array and includes:

[0014] Determine the working wavelength;

[0015] Based on the working wavelength, the pixel size of the integrated image sensor, the polarization performance of the polarizer unit in the pixel polarizer array, and the manufacturing process, respectively determine the period and height of the nano-grating array in the polarizer unit in the pixel polarizer array;

[0016] Based on the period and duty cycle of the nano-grating array, and with the goal of making the extinction ratios of the nano-grating arrays in the 0° polarizer unit, the 90° polarizer unit, the 45° polarizer unit, and the 135° polarizer unit within the working wavelength equal, determine the line width of the nano-grating array.

[0017] In a third aspect, the present invention also provides a polarization imaging device, including: the pixel polarizer array and an image sensor based on any one of the above.

[0018] According to the polarization imaging device provided by the present invention, in an off-chip integration manner, the pixel polarizer array and the image sensor are integrated in a one-to-one pixel correspondence.

[0019] The present invention also provides an electronic device, including a memory, a processor, and a computer program stored on the memory and executable on the processor. When the processor executes the program, it implements the pixel polarizer array design method as described in the second aspect above.

[0020] The present invention also provides a non-transitory computer-readable storage medium, on which a computer program is stored. When the computer program is executed by a processor, it implements the pixel polarizer array design method as described in the second aspect above.

[0021] The present invention also provides a computer program product, including a computer program. When the computer program is executed by a processor, it implements the pixel polarizer array design method as described in the second aspect above.

[0022] The pixel polarizer array provided by the present invention, its design method, and the polarization imaging device include: a substrate and a metal nano-grating array. Among them, the metal nano-grating array is disposed on the upper surface of the substrate, and the substrate is used to support the metal nano-grating array. The metal nano-grating array is composed of a plurality of polarization units arranged periodically; the polarization unit is composed of a plurality of polarizer sub-units arranged in a polarization direction; the polarizer sub-unit is composed of nano-grating arrays with polarization directions of 0°, 45°, 90°, and 135°; the line width of the nano-grating array in the 0° polarizer sub-unit is equal to the line width of the nano-grating array in the 90° polarizer sub-unit, and the line width of the nano-grating array in the 45° polarizer sub-unit is equal to the line width of the nano-grating array in the 135° polarizer sub-unit; the size of the polarizer sub-unit is the same as the pixel size of the integrated image sensor. The equalization design of the extinction ratio of the polarizer sub-units with different polarization directions improves the uniformity of the extinction ratio of the polarizer sub-units with different polarization directions and the overall extinction ratio. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0024] Figure 1 It is one of the schematic structural diagrams of the pixel polarizer array provided by the present invention;

[0025] Figure 2 It is a schematic diagram of the extinction ratio results of the polarizer sub-units in four polarization directions of the pixel polarizer array provided by the prior art;

[0026] Figure 3 It is another schematic structural diagram of the pixel polarizer array provided by the present invention;

[0027] Figure 4 It is one of the schematic diagrams of the extinction ratio results of the polarizer sub-units in four polarization directions of the pixel polarizer array provided by the present invention;

[0028] Figure 5 It is another schematic diagram of the extinction ratio results of the polarizer sub-units in four polarization directions of the pixel polarizer array provided by the present invention;

[0029] Figure 6 It is yet another schematic diagram of the extinction ratio results of the polarizer sub-units in four polarization directions of the pixel polarizer array provided by the present invention;

[0030] Figure 7It is the fourth schematic diagram of the extinction ratio results of the polarization sub-units in four polarization directions of the pixel polarizer array provided by the present invention;

[0031] Figure 8 It is the fifth schematic diagram of the extinction ratio results of the polarization sub-units in four polarization directions of the pixel polarizer array provided by the present invention;

[0032] Figure 9 It is the schematic flow chart of the pixel polarizer array design method provided by the present invention;

[0033] Figure 10 It is the schematic structural diagram of the polarization imaging device provided by the present invention;

[0034] Figure 11(a) is the schematic diagram of the comparison result of the extinction ratio histograms measured by two polarization imaging devices provided by the present invention;

[0035] Figure 11(b) is the schematic diagram of the comparison result of the extinction ratios measured by two polarization imaging devices provided by the present invention;

[0036] Figure 12(a) is the schematic diagram of the imaging result of the polarization imaging device integrated with the pixel polarizer array 2 provided by the present invention;

[0037] Figure 12(b) is the schematic diagram of the imaging result of the polarization imaging device integrated with the pixel polarizer array 1 provided by the present invention;

[0038] Figure 13 It is the schematic structural diagram of the pixel polarizer array design device provided by the present invention;

[0039] Figure 14 It is the physical structure diagram of the electronic device provided by the present invention. Detailed implementation manners

[0040] To make the objectives, technical solutions and advantages of the present invention clearer, the technical solutions in the present invention will be clearly and completely described below with reference to the accompanying drawings in the present invention. Obviously, the described embodiments are some but not all of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art without creative efforts based on the embodiments in the present invention belong to the scope of protection of the present invention.

[0041] The following Figure 1 - Figure 1 2 describes the pixel polarizer array of the present invention, its design method and the polarization imaging device.

[0042] Figure 1 It is one of the schematic structural diagrams of the pixel polarizer array provided by the present invention, as Figure 1As shown in the figure, the pixel polarizer array includes a substrate 101 and a metal nano-grating array 102. Among them, the metal nano-grating array 102 is disposed on the upper surface of the substrate 101, and the substrate 101 is used to support the metal nano-grating array 102. The metal nano-grating array 102 is composed of a plurality of polarization units 103 arranged periodically; the polarization unit 103 is composed of a plurality of polarizer sub-units 104 arranged in a polarization direction; the polarizer sub-unit 104 is composed of nano-grating arrays with polarization directions of 0°, 45°, 90°, and 135°; the line width of the nano-grating array in the 0° polarizer sub-unit 104 is equal to the line width of the nano-grating array in the 90° polarizer sub-unit 104, and the line width of the nano-grating array in the 45° polarizer sub-unit 104 is equal to the line width of the nano-grating array in the 135° polarizer sub-unit 104; the size of the polarizer sub-unit 104 is the same as the pixel size of the integrated image sensor.

[0043] Specifically, the length, width, and height of each polarizer sub-unit 104 in the polarization unit 103 are the same. The size of the polarizer sub-unit 104 is the same as the pixel size of the integrated image sensor. Four polarizer sub-units 104 in the polarization unit 103 form a 2×2 polarization "super-pixel" polarizer array unit. The upper surface of the polarizer sub-unit 104 can be square. The line width of the nano-grating array in the 0° polarizer sub-unit 104 is equal to the line width of the nano-grating array in the 90° polarizer sub-unit 104, and the line width of the nano-grating array in the 45° polarizer sub-unit 104 is equal to the line width of the nano-grating array in the 135° polarizer sub-unit 104. The size of the polarizer sub-unit 104 is the same as the pixel size of the integrated image sensor. For example, the size of the polarizer sub-unit 104 is 6.45 μm, and the image sensor is a Charge-Coupled Device (CCD) image sensor. By setting different line widths, the extinction ratios of polarizer sub-units 104 with different polarization directions are kept the same, improving the extinction ratio uniformity and the overall extinction ratio of the pixel polarizer array.

[0044] It should be noted that the geometric parameter design of the nano-grating can greatly improve the extinction ratio and its uniformity of the pixel polarizer array. The description is as follows:

[0045] The polarization state of light can be described by Stokes parameters. The first three terms (S 0 , S 1 , S 2 ) of the Stokes parameters can be obtained from the light intensity information I(0), I(45), I(90), I(135) transmitted through pixels in four different polarization directions (0°, 45°, 90°, and 135°), and are respectively expressed by formulas (1)-(3):

[0046] S 0 = I(0) + I(90)(1)

[0047] S 1 = I(0) - I(90)(2)

[0048] S 2 = I(45) - I(135)(3)

[0049] Among them, the light intensity information I(0), I(45), I(90), and I(135) are obtained by converting the signals received by the CCD.

[0050] The degree of linear polarization (DOLP) and the angle of linear polarization (AOLP) are respectively expressed by formulas (4) and (5):

[0051]

[0052]

[0053] The extinction ratio k of the nano-grating is expressed by formula (6):

[0054]

[0055] Among them, T max represents the maximum transmittance of the incident light passing through the pixelated nano-grating in the 0° direction, and T min represents the minimum transmittance of the incident light passing through the pixelated nano-grating in the 0° direction. I 0 represents the light intensity of the incident light incident on the surface of the nano-grating, and I max represents the maximum light intensity of the incident light passing through the nano-grating, and I min represents the minimum light intensity of the incident light passing through the nano-grating.

[0056] Due to the finiteness of the actual extinction ratio of the nano-grating, even when the direction of the nano-grating is perpendicular to the polarization direction of the incident light, the transmittance of the nano-grating is not 0. According to Malus' law, the intensities of polarized light in four different directions (0°, 45°, 90°, and 135°) can be respectively expressed by formulas (7)-(10):

[0057] I(0) = I 0 (T max cos 2 θ + T min sin 2 θ) (7)

[0058]

[0059] I(90)=I 0 (T max sin 2 θ+T min cos 2 θ) (9)

[0060]

[0061] Where θ represents the angle between the incident light and the nanograting in the 0° direction, T' max represents the maximum transmittance of the pixelated nano-grating at 45°, T' min Represents the minimum transmittance of the pixelated nano-grating in the 45° direction.

[0062] According to formula (7)-formula (10), we can get:

[0063]

[0064] Here, A represents the amplitude of the incident light.

[0065] Let k 1 and k 2 Represents the extinction ratio of the pixel polarization grating at 0° and 45°, respectively, m=k 1 / k 2 ,but:

[0066]

[0067] In the nano-grating polarization array designed in the prior art, the pixel units (polarization units) in different polarization directions have the same period and duty cycle. On the one hand, DOLP represents the polarization measurement accuracy, which is affected by two variables, m and k. For a specific incident light, the more uneven the extinction ratio between pixel units in different directions (the greater the deviation of the m value from 1), the lower the measurement accuracy. On the other hand, the larger the extinction ratio k value, the higher the measurement accuracy. Therefore, in order to improve the measurement accuracy, when designing a pixel polarizer, it is necessary to increase the extinction ratio of the pixel unit and the uniformity of the extinction ratio between the pixel units as much as possible.

[0068] Optionally, the material of the substrate is any one of transparent materials, the material of the nano-grating array is any one of metal materials, and the material of the anti-crosstalk area is any one of metal materials.

[0069] Specifically, the material of the substrate is any transparent material, for example, the material of the substrate is quartz; the material of the nanograting array is any metal material, for example, the material of the nanograting array is aluminum; the material of the anti-crosstalk zone is any metal material, for example, the material of the anti-crosstalk zone is aluminum.

[0070] Figure 2 It is a schematic diagram of the extinction ratio results of the polarizer units in four polarization directions of the pixel polarizer array provided by the prior art. As Figure 2 shown, the parameters of the nano-grating array designed in the wavelength range of 400 - 700 nanometers (nm) are: the substrate material is quartz, the material of the nano-gratings is aluminum, the size of the polarizer unit is 6.45 micrometers (μm), the period and height of the nano-gratings are both 120 nm, the line width of the nano-gratings in each polarizer unit is 60 nm, and no anti-crosstalk area is set. Figure 2 The extinction ratio results of the polarizer units in two groups of directions are given. It can be seen that the extinction ratios of the polarizer units in the two groups of directions are not equal (m is not equal to 1), and the difference in the extinction ratios is large, the uniformity of the extinction ratio is poor, and the overall extinction ratio value is low.

[0071] The pixel polarizer array provided by the present invention includes: a substrate and a metal nano-grating array, wherein the metal nano-grating array is disposed on the upper surface of the substrate, the substrate is used to support the metal nano-grating array, and the metal nano-grating array is composed of a plurality of periodically arranged polarization units; the polarization unit is composed of a plurality of polarizer units arranged in polarization directions; the polarizer unit is composed of nano-grating arrays in polarization directions of 0°, 45°, 90°, and 135°; the line width of the nano-grating array in the 0° polarizer unit is equal to the line width of the nano-grating array in the 90° polarizer unit, and the line width of the nano-grating array in the 45° polarizer unit is equal to the line width of the nano-grating array in the 135° polarizer unit; the size of the polarizer unit is the same as the pixel size of the integrated image sensor. The equalization design of the extinction ratios of the polarizer units in different polarization directions improves the uniformity of the extinction ratio and the overall extinction ratio of the pixel polarizer array.

[0072] Optionally, the extinction ratio of the nano-grating array in the 0° polarizer unit, the extinction ratio of the nano-grating array in the 90° polarizer unit, the extinction ratio of the nano-grating array in the 45° polarizer unit, and the extinction ratio of the nano-grating array in the 135° polarizer unit are equal.

[0073] Specifically, the line width of the nano-grating array in the 0° polarizer unit is equal to the line width of the nano-grating array in the 90° polarizer unit, and the line width of the nano-grating array in the 45° polarizer unit is equal to the line width of the nano-grating array in the 135° polarizer unit. The equalization design of the extinction ratios of the polarizer units in different polarization directions improves the uniformity of the extinction ratio and the overall extinction ratio of the pixel polarizer array.

[0074] Optionally, the pixel polarizer array further includes: an opaque anti-crosstalk region disposed between adjacent polarizer units, and the opaque anti-crosstalk region is used to block signal crosstalk between the adjacent polarizer units.

[0075] Specifically, the pixel polarizer array may further include an opaque anti-crosstalk region, wherein the opaque anti-crosstalk region is disposed between adjacent polarizer units, and the opaque anti-crosstalk region is used to block signal crosstalk between the adjacent polarizer units, thereby improving the polarization performance of the nano-grating.

[0076] Figure 3 is the second structural schematic diagram of the pixel polarizer array provided by the present invention, as Figure 3 shown, the pixel polarizer array includes a substrate 301, a metal nano-grating array 302, and an opaque anti-crosstalk region 303. Among them, the metal nano-grating array 302 is disposed on the upper surface of the substrate 301, and the substrate 301 is used to support the metal nano-grating array 302. The metal nano-grating array 302 is composed of a plurality of polarization units 304 arranged periodically; the polarization unit 304 is composed of a plurality of polarizer units 305 arranged in a polarization direction; the polarizer unit 305 is composed of a nano-grating array; the opaque anti-crosstalk region 303 is disposed between adjacent polarizer units 305, and the opaque anti-crosstalk region 303 is used to block signal crosstalk between the adjacent polarizer units 305.

[0077] It should be noted that by providing an opaque anti-crosstalk region, that is, an opaque region, between adjacent polarizer units, the coupling effect of the electric fields between adjacent polarizer units (pixel sub-units) is eliminated as much as possible. Under the same incident conditions, the light intensities transmitted by the polarizer units with 0° (90°) and adjacent 45° (135°) polarization directions satisfy Malus' law:

[0078] I = I 0 cos 2 θ (13)

[0079]

[0080] wherein, I represents the light intensity transmitted by the polarizer unit, and I(0) and I(45) respectively represent the light intensities of the incident light with 0° and 45° polarization directions transmitted through the polarizer unit.

[0081] It should be noted that an opaque anti-crosstalk region with an appropriate width can significantly reduce the minimum transmittance of the polarizer unit, while having little impact on the maximum transmittance. When the width of the opaque anti-crosstalk region is too large, the area of the nano-grating in the polarizer unit becomes smaller, reducing the polarization performance of the grating; when the width of the opaque anti-crosstalk region is too small, the signal crosstalk between the polarizer units is serious, which will also reduce the polarization performance of the grating.

[0082] According to Malus' law, it can be determined whether the width of the light-tight crosstalk prevention area is reasonably set. When the ratio of I(45) to I(0) is not equal to 1 / 2, it indicates that the width of the light-tight crosstalk prevention area is not reasonably set, and the width of the light-tight crosstalk prevention area needs to be adjusted until the ratio of I(45) to I(0) is equal to 1 / 2. At this time, the width of the set light-tight crosstalk prevention area is the finally determined width of the light-tight crosstalk prevention area.

[0083] Optionally, the width of the crosstalk prevention area is less than the size of the polarizer unit, and the height of the crosstalk prevention area is the same as the height of the pixel polarizer array.

[0084] Specifically, the width of the crosstalk prevention area is less than the size of the polarizer unit, so that the area of the nano-grating in the polarizer unit can be larger than the area of the crosstalk prevention area, and thus the incident light can pass through the polarizer unit better, improving the polarization performance of the nano-grating.

[0085] Preferably, in the wavelength range of 400 - 700 nm, the width of the crosstalk prevention area is 800 nm. When the width of the crosstalk prevention area is 800 nm, the ratio of I(45) to I(0) is equal to 1 / 2, and at this time, the polarization performance of the grating is the best.

[0086] Figure 4 is one of the schematic diagrams of the extinction ratio results of the polarizer units in four polarization directions of the pixel polarizer array provided by the present invention. As Figure 4 shown, a light-tight crosstalk prevention area is added between adjacent polarizer units in the polarization unit of the metal nano-grating polarization array. The height of the light-tight crosstalk prevention area is the same as the height of the nano-metal grating, and the width of the light-tight crosstalk prevention area is 800 nm. The parameters of the pixel polarizer array are: the substrate material is quartz, the material of the metal nano-grating array is aluminum, the size of the polarizer unit is 6.4 μm, the period and height of the nano-grating array are both 120 nm, and the line width of the nano-grating array in the polarizer units in four polarization directions is 60 nm. Figure 4 The extinction ratio results of the polarizer units in two groups of directions are given. Thus, compared with Figure 2 the extinction ratio results of the polarizer units in two groups of directions shown, due to the elimination of signal crosstalk between adjacent polarizer units (pixels), the extinction ratios of the polarizer units in both groups of directions are significantly improved, but the extinction ratios are still not uniform.

[0087] Optionally, the line width of the nano-grating array in the 0° polarizer unit is less than the line width of the nano-grating array in the 45° polarizer unit; the line width of the nano-grating array in the 90° polarizer unit is less than the line width of the nano-grating array in the 135° polarizer unit.

[0088] Specifically, the line width of the nano-grating array in the 0° polarizer unit is less than that in the 45° polarizer unit; the line width of the nano-grating array in the 90° polarizer unit is less than that in the 135° polarizer unit. The equal extinction ratio design of the polarizer units with different polarization directions improves the extinction ratio uniformity and the overall extinction ratio of the polarizer units with different polarization directions.

[0089] According to Figure 2 and Figure 4 the problems existing in the extinction ratio results of the polarizer units in the two groups of directions shown, assuming that the extinction ratio of the nano-grating array in the polarizer unit with the 0° (90°) polarization direction is ER 1 and the extinction ratio of the nano-grating array in the polarizer unit with the 45° (135°) polarization direction is ER 2 , with the goal of making the extinction ratio ER 1 and the extinction ratio ER 2 equal within the working wavelength band, determine the line widths of the nano-grating arrays in the polarizer units with the 0° and 90° polarization directions and the 45° and 135° polarization directions, and set opaque anti-crosstalk regions between adjacent polarizer units. The width of the anti-crosstalk region is determined to reduce the crosstalk of signals between adjacent polarizer units and improve the polarization performance of the nano-gratings.

[0090] Preferably, in the wavelength range of 400 - 700 nm, the line width of the nano-grating array in the 0° polarizer unit and the line width of the nano-grating array in the 90° polarizer unit are both 61 nm, and the line width of the nano-grating array in the 45° polarizer unit and the line width of the nano-grating array in the 135° polarizer unit are both 65 nm.

[0091] Figure 5 is the second schematic diagram of the extinction ratio results of the polarizer units in the four polarization directions of the pixel polarizer array provided by the present invention. As Figure 5 shown, the pixel polarizer array includes: a substrate, a metal nano-grating array periodically arranged on the upper surface of the substrate, and an opaque anti-crosstalk region; the basic unit of the substrate and the corresponding metal nano-grating array is composed of four polarizer units formed by nano-grating arrays in four polarization directions of 0°, 45°, 90°, and 135°. The size of the polarizer unit is the same as that of the image sensor pixel it integrates, and the size of the polarizer unit is 6.45 μm. The four polarizer units form a 2×2 polarization "super-pixel" polarizer array unit; multiple polarization "super-pixel" polarizer array units form a metal nano-grating array.

[0092] The parameters of the nano-grating arrays in four polarization directions are as follows: the period of the nano-gratings is 120 nm, the height is 120 nm, the line width of the nano-grating arrays in the polariton units with polarization directions of 0° and 90° is 61 nm, the line width of the nano-grating arrays in the polariton units with polarization directions of 45° and 135° is 65 nm, the width of the light-blocking anti-crosstalk region 220 is 800 nm, and the height of the light-blocking anti-crosstalk region is 120 nm. In the wavelength range of 400 - 700 nm, the extinction ratio of the nano-grating arrays is as Figure 5 shown. It can be seen from Figure 5 that the extinction ratios of the polariton units in the four polarization directions are significantly improved compared with before, and the extinction ratios of the polariton units in the four polarization directions are basically the same, greatly improving the extinction ratio uniformity of the pixel polarizer array. For example, the extinction ratio of the polariton unit at a wavelength of 700 nm reaches 7000.

[0093] Next, some specific embodiments will be used to illustrate the pixel polarizer array provided by the present invention.

[0094] Figure 6 FIG. Figure 6 shows a third schematic diagram of the extinction ratio results of the polariton units in the four polarization directions of the pixel polarizer array provided by the present invention. As shown in

[0095] FIG., the pixel polarizer array includes: a substrate, a metal nano-grating array periodically arranged on the upper surface of the substrate, and a light-blocking anti-crosstalk region. The basic unit of the substrate and the corresponding metal nano-grating array is composed of four polariton units formed by nano-gratings with polarization directions of 0°, 45°, 90°, and 135°. The size of the polariton unit is the same as that of the image sensor pixel integrated, and the size of the polariton unit is 6.45 μm. The four polariton units form a 2×2 polarization "super-pixel" polarizer array unit; a plurality of polarization "super-pixel" polarizer array units form a polarization array. Figure 6 shown. It can be seen from Figure 6 that the extinction ratios of the polariton units in the four polarization directions are greatly improved compared with before, and the extinction ratios of the polariton units in the four polarization directions are basically the same, greatly improving the extinction ratio uniformity of the pixel polarizer array. For example, the extinction ratio of the polariton unit at a wavelength of 700 nm reaches 2700.

[0096] Figure 7It is the fourth schematic diagram of the extinction ratio results of the polarizer units with four polarization directions in the pixel polarizer array provided by the present invention. As Figure 7 shown, the pixel polarizer array includes: a substrate, a metal nano-grating array periodically arranged on the upper surface of the substrate, and an opaque anti-crosstalk region; the basic unit of the substrate and the corresponding metal nano-grating array is composed of four polarizer units formed by nano-gratings with four polarization directions of 0°, 45°, 90°, and 135°. The size of the polarizer unit is the same as that of the image sensor pixel integrated, the size of the polarizer unit is 7.4 μm, and the four polarizer units form a 2×2 polarization "super-pixel" polarizer array unit; a plurality of polarization "super-pixel" polarizer array units form a polarization array.

[0097] The parameters of the nano-grating arrays with four polarization directions are: the nano-grating period is 140 nm, the height is 140 nm, the line width of the nano-grating array in the polarizer units with 0° and 90° polarization directions is 70 nm, and the line width of the nano-grating array in the polarizer units with 45° and 135° polarization directions is 83 nm; the width of the opaque anti-crosstalk region is 800 nm, and the height of the opaque anti-crosstalk region is 120 nm. In the wavelength range of 400 - 700 nm, the extinction ratio of the nano-grating array is as Figure 7 shown. As can be seen from Figure 7 it, the extinction ratios of the polarizer units with four polarization directions are significantly improved compared with before, and the extinction ratios of the polarizer units with four polarization directions are basically the same, greatly improving the extinction ratio uniformity of the pixel polarizer array. For example, the extinction ratio at a wavelength of 700 nm reaches 13000.

[0098] Figure 8 It is the fifth schematic diagram of the extinction ratio results of the polarizer units with four polarization directions in the pixel polarizer array provided by the present invention. As Figure 8 shown, the pixel polarizer array includes: a substrate, a metal nano-grating array periodically arranged on the upper surface of the substrate, and an opaque anti-crosstalk region; the basic unit of the substrate and the corresponding metal nano-grating array is composed of four polarizer units formed by nano-gratings with four polarization directions of 0°, 45°, 90°, and 135°. The size of the polarizer unit is the same as that of the image sensor pixel integrated, the size of the polarizer unit is 7.4 μm, and the four polarizer units form a 2×2 polarization "super-pixel" polarizer array unit; a plurality of polarization "super-pixel" polarizer array units form a polarization array.

[0099] The parameters of the nano-grating arrays with four polarization directions are as follows: the period of the nano-gratings is 160 nm, the height is 140 nm, the line width of the nano-grating arrays in the polariton units with 0° and 90° polarization directions is 80 nm, and the line width of the nano-grating arrays in the polariton units with 45° and 135° polarization directions is 92 nm; the width of the light-blocking anti-crosstalk region is 800 nm, and the height of the light-blocking anti-crosstalk region is 120 nm. In the wavelength range of 400 - 700 nm, the extinction ratio of the nano-grating arrays is as Figure 8 shown. It can be seen from Figure 8 that the extinction ratios of the polariton units with four polarization directions are greatly improved, and the extinction ratios of the polariton units with four polarization directions are basically the same, which greatly improves the extinction ratio uniformity of the pixel polarizer array. For example, the extinction ratio at 700 nm wavelength reaches 5500.

[0100] For the pixel polarizer array provided by the present invention, in terms of the preparation process, micro-nano processing technology can be used for batch preparation, with low cost, simple process, good stability, no use of toxic chemicals during the preparation process, and environmental friendliness.

[0101] Figure 9 is a schematic flow chart of the pixel polarizer array design method provided by the present invention, as Figure 9 shown. The method includes steps 901 - 903; wherein,

[0102] Step 901, determine the working wavelength.

[0103] Specifically, according to the actual application requirements, determine the working wavelength λ. For example, determine the working wavelength to be 400 - 700 nm. It is also necessary to determine the materials of the metal nano-grating array and the substrate according to the actual application requirements. For example, the material of the metal nano-grating array is aluminum, and the material of the substrate is quartz.

[0104] Step 902, based on the working wavelength, the pixel size of the integrated image sensor, the polarization performance of the polariton units in the pixel polarizer array, and the preparation process, respectively determine the period and height of the nano-grating arrays in the polariton units in the pixel polarizer array.

[0105] Specifically, according to the working wavelength, the period of the nano-grating array in the polarizer unit of the pixel polarizer array can be determined. Since only the zero-order diffraction exists in the sub-wavelength metal nano-grating, the polarization property of light can be better highlighted. Therefore, within the working wavelength, the period of the nano-grating array can be determined. For example, the period is 120 nm. According to the pixel size of the integrated image sensor, the polarization performance of the polarizer unit in the pixel polarizer array, and the manufacturing process, the height of the nano-grating will affect the extinction performance of the nano-grating. The greater the height, the stronger the extinction performance of the nano-grating. In order to improve the polarization performance of the nano-grating and reduce the difficulty of fabricating the grating, 120 nm is selected as the height of the nano-grating array.

[0106] Step 903: Based on the period and duty cycle of the nano-grating array, and aiming at the equal extinction ratios of the nano-grating arrays in the 0° polarizer unit, the 90° polarizer unit, the 45° polarizer unit, and the 135° polarizer unit within the working wavelength, determine the line width of the nano-grating array.

[0107] Specifically, a preset duty cycle is set. For example, the preset duty cycle is 0.5. According to the preset duty cycle and the period of the nano-grating array, the line width of the nano-grating array is determined, that is, multiplying the period of the nano-grating array by the duty cycle equals the line width of the nano-grating array. Therefore, near 60 nm, by continuously changing the preset duty cycle and the period of the nano-grating array, the most suitable width is found as the line width of the polarizer unit in different polarization directions, so that the extinction ratios of the nano-grating arrays in the 0° (90°) and 45° (135°) polarization direction polarizer units are equal.

[0108] The pixel polarizer array design method provided by the present invention determines the period and height of the nano-grating array in the polarizer unit of the pixel polarizer array respectively by determining the working wavelength and according to the working wavelength, the pixel size of the integrated image sensor, the polarization performance of the polarizer unit in the pixel polarizer array, and the manufacturing process; then, based on the period and duty cycle of the nano-grating array, and aiming at the equal extinction ratios of the nano-grating arrays in the 0° polarizer unit, the 90° polarizer unit, the 45° polarizer unit, and the 135° polarizer unit within the working wavelength, determine the line width of the nano-grating array, thereby improving the uniformity of the extinction ratio of the overall pixel polarizer array.

[0109] Figure 10 is a schematic structural diagram of the polarization imaging device provided by the present invention, as Figure 10As shown in the figure, the polarization imaging device 1000 includes a pixel polarizer array 1001 and an image sensor 1002.

[0110] Optionally, in an off-chip integration manner, the pixel polarizer array and the image sensor are integrated in a one-to-one pixel correspondence.

[0111] Specifically, in the integration area of the polarization imaging device, in an off-chip integration manner, the pixel polarizer array and the image sensor are integrated in a one-to-one pixel correspondence; wherein, the image sensor is a CCD image sensor.

[0112] A pixel polarizer array (pixel polarizer array 1) with an extinction ratio as shown in Figure 4 and a pixel polarizer array (pixel polarizer array 2) with an extinction ratio as shown in Figure 5 are respectively integrated with the CCD image sensor in a one-to-one pixel correspondence to obtain two polarization imaging devices. For example, in the pixel polarizer array with an extinction ratio as shown in Figure 4 , the size of the polarizer unit in the pixel polarizer array is 6.45 μm, the period and height of the nano-grating array are both 120 nm, and the line width of the nano-grating array in the polarizer units with polarization directions of 0° (90°) and 45° (135°) are both 60 nm; an opaque anti-crosstalk area is provided. As shown in Figure 5 , the period of the polarizer unit in the pixel polarizer array with an extinction ratio as shown is 6.45 μm, the period and height of the nano-grating array are both 120 nm, the line width of the nano-grating array in the polarizer units with polarization directions of 0° (90°) is 61 nm, the line width of the nano-grating array in the polarizer units with polarization directions of 45° (135°) is 65 nm, and the width of the opaque anti-crosstalk area is 800 nm.

[0113] Figure 11(a) is a schematic diagram of the comparison result of the extinction ratio histograms measured by the two polarization imaging devices provided by the present invention. At a wavelength of 633 nm, when the line width of the nano-grating array in the polarizer units in the four polarization directions in the polarization imaging device integrated with the pixel polarizer array 1 is 60 nm, the extinction ratio of the polarization imaging device integrated with the pixel polarizer array 1 is mainly distributed between 6 and 16, and the average extinction ratio is 14.5. It can be seen that the extinction ratio distribution is very scattered, and the extinction ratio greater than 100 still accounts for a large proportion, and the overall extinction ratio uniformity is poor. While when the line width of the nano-grating array in the polarizer units with polarization directions of 0° and 90° in the polarization imaging device integrated with the pixel polarizer array 2 is 61 nm and the line width of the nano-grating array in the polarizer units with polarization directions of 45° and 135° is 65 nm, the extinction ratio of the polarization imaging device is significantly improved, mainly concentrated between 20 and 40, the extinction ratio distribution is more concentrated, the average extinction ratio reaches 36, and both the overall extinction ratio and uniformity are significantly improved.

[0114] Figure 11(b) is a schematic diagram of the contrast result of the extinction ratio measured by two polarization imaging devices provided by the present invention. As shown in Figure 11(b), in the wavelength range of 500 - 700 nm, the extinction ratio is measured using the two polarization imaging devices listed in Figure 11(a). It can be seen from Figure 11(b) that in the wavelength range of 500 - 700 nm, the extinction ratio of the pixel polarization imaging device integrated with the pixel polarizer array 2 is greater than 28.5, which is significantly better than that of the polarization imaging device integrated with the pixel polarizer array 1.

[0115] To further verify the influence of the performance of the pixel polarizer array 1 and the pixel polarizer array 2 on the polarization imaging result, the pixel polarizer array 1 and the pixel polarizer array 2 are respectively fabricated and integrated on the same type of CCD image sensor (chip) to complete the corresponding polarization imaging devices. A laser with a wavelength of 633 nm is expanded and irradiated onto a piece of ground glass, and the polarization imaging devices are respectively used for imaging. Figure 12(a) is a schematic diagram of the imaging result of the polarization imaging device integrated with the pixel polarizer array 2 provided by the present invention, and Figure 12(b) is a schematic diagram of the imaging result of the polarization imaging device integrated with the pixel polarizer array 1 provided by the present invention. As shown in Figure 12(a) and Figure 12(b), the S 0 images (original images), degree of polarization images (i.e., DOLP images), and angle of polarization images (i.e., AOLP images) corresponding to the pixel polarizer array 2 and the pixel polarizer array 1 integrated polarization imaging devices are respectively given. It can be seen from the degree of polarization image in Figure 12(a) that the extinction ratio and uniformity of the pixel polarizer array 2 are significantly better than those of the pixel polarizer array 1, and the polarization measurement accuracy of the pixel polarizer array 2 is higher than that of the pixel polarizer array 1. Correspondingly, the resolution ability of the DOLP image and the AOLP image is stronger.

[0116] The polarization imaging device provided by the present invention has a compact structure and a small volume. Compared with traditional cameras, it can better adapt to complex environments. At night with weak light intensity, in foggy days, or when there are obstacles, the image of an object can be extracted by obtaining polarization information, which has broad application prospects in the fields of industrial inspection, medical detection, or military target recognition.

[0117] The pixel polarizer array design device provided by the present invention will be described below. The pixel polarizer array design device described below can be mutually referred to with the pixel polarizer array design method described above.

[0118] Figure 13 is a schematic structural diagram of the pixel polarizer array design device provided by the present invention. As Figure 13 shown, the pixel polarizer array design device 1300 includes: a first determination module 1301, a second determination module 1302, and a third determination module 1303; wherein,

[0119] The first determination module 1301 is configured to determine the working wavelength;

[0120] The second determination module 1302 is configured to respectively determine the period and height of the nano-grating array in the polarizer unit of the pixel polarizer array based on the working wavelength, the pixel size of the integrated image sensor, the polarization performance of the polarizer unit in the pixel polarizer array, and the manufacturing process;

[0121] The third determination module 1303 is configured to determine the line width of the nano-grating array based on the period and duty cycle of the nano-grating array, with the goal of making the extinction ratio of the nano-grating array in the 0° polarizer unit, the extinction ratio of the nano-grating array in the 90° polarizer unit, the extinction ratio of the nano-grating array in the 45° polarizer unit, and the extinction ratio of the nano-grating array in the 135° polarizer unit equal within the working wavelength.

[0122] The pixel polarizer array design device provided by the present invention determines the working wavelength, and respectively determines the period and height of the nano-grating array in the polarizer unit of the pixel polarizer array according to the working wavelength, the pixel size of the integrated image sensor, the polarization performance of the polarizer unit in the pixel polarizer array, and the manufacturing process; then, according to the period and duty cycle of the nano-grating array, with the goal of making the extinction ratio of the nano-grating array in the 0° polarizer unit, the extinction ratio of the nano-grating array in the 90° polarizer unit, the extinction ratio of the nano-grating array in the 45° polarizer unit, and the extinction ratio of the nano-grating array in the 135° polarizer unit equal within the working wavelength, it determines the line width of the nano-grating array, thereby improving the extinction ratio uniformity of the overall pixel polarizer array.

[0123] Figure 14 It is a schematic diagram of the physical structure of an electronic device provided by the present invention, as Figure 14As shown, the electronic device 1400 may include: a processor 1410, a communications interface 1420, a memory 1430, and a communication bus 1440. Among them, the processor 1410, the communications interface 1420, and the memory 1430 complete their mutual communication through the communication bus 1440. The processor 1410 may call the logical instructions in the memory 1430 to execute the pixel polarizer array design method, which includes: determining the working wavelength; based on the working wavelength, the pixel size of the integrated image sensor, the polarization performance of the polarizer units in the pixel polarizer array, and the manufacturing process, respectively determining the period and height of the nano-grating array in the polarizer units in the pixel polarizer array; based on the period and duty cycle of the nano-grating array, and with the goal that the extinction ratio of the nano-grating array in the 0° polarizer unit, the extinction ratio of the nano-grating array in the 90° polarizer unit, the extinction ratio of the nano-grating array in the 45° polarizer unit, and the extinction ratio of the nano-grating array in the 135° polarizer unit within the working wavelength are equal, determining the line width of the nano-grating array.

[0124] In addition, when the logical instructions in the above-mentioned memory 1430 are implemented in the form of software functional units and sold or used as an independent product, they can be stored in a computer-readable storage medium. Based on such an understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art, or a part of this technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions for causing a computer device (which may be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the methods described in various embodiments of the present invention. The foregoing storage medium includes: various media such as USB flash drives, mobile hard disks, read-only memories (ROM, Read-Only Memory), random access memories (RAM, Random Access Memory), magnetic disks, or optical discs that can store program codes.

[0125] On the other hand, the present invention also provides a computer program product, which includes a computer program. The computer program can be stored on a non-transitory computer-readable storage medium. When the computer program is executed by a processor, the computer can execute the pixel polarizer array design method provided by the above-mentioned various methods. The method includes: determining the working wavelength; based on the working wavelength, the pixel size of the integrated image sensor, the polarization performance of the polarizer unit in the pixel polarizer array, and the manufacturing process, respectively determining the period and height of the nano-grating array in the polarizer unit in the pixel polarizer array; based on the period and duty cycle of the nano-grating array, and with the goal of making the extinction ratio of the nano-grating array in the 0° polarizer unit, the extinction ratio of the nano-grating array in the 90° polarizer unit, the extinction ratio of the nano-grating array in the 45° polarizer unit, and the extinction ratio of the nano-grating array in the 135° polarizer unit equal within the working wavelength, determining the line width of the nano-grating array.

[0126] In yet another aspect, the present invention also provides a non-transitory computer-readable storage medium, on which a computer program is stored. When the computer program is executed by a processor, it implements the pixel polarizer array design method provided by the above-mentioned various methods. The method includes: determining the working wavelength; based on the working wavelength, the pixel size of the integrated image sensor, the polarization performance of the polarizer unit in the pixel polarizer array, and the manufacturing process, respectively determining the period and height of the nano-grating array in the polarizer unit in the pixel polarizer array; based on the period and duty cycle of the nano-grating array, and with the goal of making the extinction ratio of the nano-grating array in the 0° polarizer unit, the extinction ratio of the nano-grating array in the 90° polarizer unit, the extinction ratio of the nano-grating array in the 45° polarizer unit, and the extinction ratio of the nano-grating array in the 135° polarizer unit equal within the working wavelength, determining the line width of the nano-grating array.

[0127] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separated. The components shown as units may or may not be physical units, that is, they may be located in one place, or may be distributed to multiple network units. Some or all of the modules can be selected according to actual needs to achieve the purpose of the solution of this embodiment. A person of ordinary skill in the art can understand and implement it without creative labor.

[0128] Through the description of the above embodiments, those skilled in the art can clearly understand that each embodiment can be implemented by means of software plus a necessary general hardware platform, and of course, it can also be implemented by hardware. Based on this understanding, the essence of the above technical solution, or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, magnetic disk, optical disk, etc., and includes several instructions to enable a computer device (which can be a personal computer, server, or network device, etc.) to execute the methods described in each embodiment or some parts of the embodiments.

[0129] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A pixel polarizer array, characterized in that, it includes: a substrate and a metal nanograting array, wherein the metal nanograting array is disposed on the upper surface of the substrate, the substrate is used to support the metal nanograting array, and the metal nanograting array is composed of a plurality of polarization units arranged periodically; the polarization unit is composed of a plurality of polarizer sub-units arranged in a polarization direction; the polarizer sub-unit is composed of nanograting arrays with polarization directions of 0°, 45°, 90° and 135°; the line width of the nanograting array in the 0° polarizer sub-unit is equal to the line width of the nanograting array in the 90° polarizer sub-unit, and the line width of the nanograting array in the 45° polarizer sub-unit is equal to the line width of the nanograting array in the 135° polarizer sub-unit; the size of the polarizer unit is the same as the pixel size of the integrated image sensor.

2. The pixel polarizer array according to claim 1, characterized in that, the extinction ratio of the nanograting array in the 0° polarizer sub-unit, the extinction ratio of the nanograting array in the 90° polarizer sub-unit, the extinction ratio of the nanograting array in the 45° polarizer sub-unit, and the extinction ratio of the nanograting array in the 135° polarizer sub-unit are equal.

3. The pixel polarizer array according to claim 1 or 2, characterized in that, it further includes: an opaque anti-crosstalk region, which is disposed between adjacent polarizer sub-units, and the opaque anti-crosstalk region is used to block signal crosstalk between the adjacent polarizer sub-units.

4. The pixel polarizer array according to claim 3, characterized in that, the width of the anti-crosstalk region is less than the size of the polarizer unit, and the height of the anti-crosstalk region is the same as the height of the pixel polarizer array.

5. The pixel polarizer array according to claim 1, characterized in that, the line width of the nanograting array in the 0° polarizer sub-unit is less than the line width of the nanograting array in the 45° polarizer sub-unit; the line width of the nanograting array in the 90° polarizer sub-unit is less than the line width of the nanograting array in the 135° polarizer sub-unit.

6. The pixel polarizer array according to claim 1, characterized in that, the periods and heights of the nanograting arrays in the polarizer units are the same.

7. The pixel polarizer array according to claim 4, characterized in that, the material of the substrate is any one of transparent materials, the material of the nanograting array is any one of metal materials, and the material of the anti-crosstalk region is any one of metal materials.

8. A method for designing a pixel polarizer array, characterized in that, applied to the pixel polarizer array according to any one of claims 1 to 7, and includes: determining the working wavelength; respectively determining the period and height of the nanograting array in the polarizer unit of the pixel polarizer array based on the working wavelength, the pixel size of the integrated image sensor, the polarization performance of the polarizer unit in the pixel polarizer array, and the manufacturing process. Based on the period and duty cycle of the nano-grating array, and aiming at making the extinction ratios of the nano-grating arrays in the 0° polarizer unit, the 90° polarizer unit, the 45° polarizer unit, and the 135° polarizer unit within the working wavelength equal, determine the line width of the nano-grating array.

9. A polarization imaging device, characterized in that, it includes: a pixel polarizer array and an image sensor according to any one of claims 1 to 7.

10. The polarization imaging device according to claim 9, characterized in that, in an off-chip integration manner, the pixel polarizer array and the image sensor are integrated in a one-to-one pixel correspondence.

Images