Focal plane full-polarization sensing device

Abstract

The utility model provides a focal plane full polarization sensing device, including substrate, phase delay layer, polarization detection layer and CCD sensor, the phase delay layer and polarization detection layer are arranged on one side of substrate in proper order, the phase delay layer has a plurality of phase delay zone in array arrangement, and the CCD sensor is arranged in the phase delay zone. The phase delay area comprises 2x < 2 > pixel units in different fast axis directions, the polarization detection layer is in single horizontal orientation, and the phase delay layer and the polarization detection layer are combined to form an elliptical polarization array, so that the simultaneous detection of four elliptical polarized lights is realized. The manufacturing process of the focal plane splitting polarization sensing device based on the metal wire grating is simplified, the manufacturing cost is reduced, efficient polarization imaging of the infrared band can be achieved, and the multi-band compatibility of the device is improved.

Description

TECHNICAL FIELD

[0001] The utility model relates to optical polarization technical field, especially a kind of focal plane full polarization perception device. BACKGROUND

[0002] As a new type of optical imaging technology, polarization imaging technology can suppress background noise, improve detection distance, obtain target detail features and identify camouflage targets, and has a wide application prospect in military security, industrial detection, medical diagnosis, environmental monitoring, car unmanned driving, astronomical exploration and cultural relic protection. According to the structural difference of the polarization imaging system, the existing technology usually divides the polarization imaging system into four types: time-sharing type, amplitude-dividing type, aperture-dividing type and focal plane-dividing type.

[0003] However, the current polarization imaging system is mainly limited to the visible band, and it is difficult to realize efficient and stable imaging in the infrared band. The application in the infrared band still faces many technical bottlenecks. At the same time, the focal plane polarization perception system based on metal wire grid has problems such as complex preparation process, high cost and limited effective area, which is difficult to meet the actual application requirements. SUMMARY

[0004] Therefore, it is necessary to provide a focal plane full polarization perception device for simplifying the manufacturing process and realizing multi-band compatibility.

[0005] The utility model provides a kind of focal plane full polarization perception device, including substrate, phase delay layer, polarization detection layer and CCD sensor, the phase delay layer and the polarization detection layer are sequentially arranged on substrate side, the phase delay layer has multiple array arrangement phase delay area, the phase delay area includes 2x 2 different fast axis direction pixel unit, the phase delay layer modulates incident light into different angle polarized light.

[0006] Specifically, the polarization detection layer is single horizontally oriented, and the phase delay layer and the polarization detection layer form an elliptical polarization array.

[0007] Specifically, the phase delay layer is a wide-band phase delay layer prepared by liquid crystal polymer molecular structure.

[0008] Specifically, the angle between the fast axis direction and the horizontal direction is in the range of ±13.1° to ±17.1° and ±49.7° to ±53.7°.

[0009] Specifically, the phase delay of the phase delay layer satisfies the formula: 2π×0.36≤δ≤2π×0.37.

[0010] Specifically, the polarization detection layer is a double-layer wire grid structure, and the polarization detection layer screens linearly polarized light of a specific direction after being modulated by the phase delay layer.

[0011] Specifically, the polarization detection layer comprises a high-transmittance substrate, a dielectric wire grid layer and a metal wire grid layer, the dielectric wire grid layer and the metal wire grid layer are sequentially arranged on the high-transmittance substrate, and the dielectric wire grid layer and the metal wire grid layer are arranged in the same direction.

[0012] Specifically, the arrangement period of the metal wire grid in the metal wire grid layer is 140nm-180nm, and the height of the metal wire grid is 30nm-40nm.

[0013] Specifically, the width of a single metal wire grid in the metal wire grid layer is 35nm-45nm, and the pixel size of the single metal wire grid is 100μm*100μm.

[0014] Specifically, the pixels of the metal wire grid correspond to the pixels of the CCD sensor one by one.

[0015] In summary, the full-polarization perception device with a split focal plane has the following advantages:

[0016] 1. The four-pixel elliptical polarization principle simplifies the preparation process of the split focal plane polarization perception device based on the metal wire grid, reduces the manufacturing cost, can realize efficient polarization imaging in the infrared band, and improves the multi-band compatibility of the device.

[0017] 2. The four elliptical polarized lights can be detected at the same time, the full-Stokes vector polarization information of the same target scene can be obtained at one time, and the structure is simple, and real-time full-polarization imaging can be realized.

[0018] 3. Compared with a simple full-Stokes micro-polarization array, the pixel-level repeated alignment in the manufacturing process is avoided, and the defect density of the micro-polarization array is reduced. BRIEF DESCRIPTION OF DRAWINGS

[0019] In order to more clearly illustrate the technical scheme of the embodiments of the present application, the following will briefly introduce the drawings needed in the embodiments. It should be understood that the following drawings only show some embodiments of the present application, and therefore should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can also be obtained without creative labor on the basis of these drawings.

[0020] Figure 1 Fig. 1 is a structural schematic view of a split focal plane full-polarization perception device;

[0021] Figure 2 Fig. 3 is a schematic view of the arrangement structure of a phase delay layer.

[0022] Figure 3 schematic view of pixel unit structure in phase delay layer;

[0023] Figure 4 schematic view of single orientation structure in polarization detection layer;

[0024] Figure 5 schematic view of cross section of double layer grating structure arrangement in polarization detection layer;

[0025] In the above drawings, the reference signs of the embodiments of the present application are as follows:

[0026] 1, substrate; 2, phase delay layer; 3, polarization detection layer; 4, CCD sensor; 21, phase delay area; 211, pixel unit; 31, high light transmittance substrate; 32, dielectric grating layer; 33, metal grating layer. DETAILED DESCRIPTION

[0027] The specific embodiments of the present application will be described in detail below with reference to the drawings. Obviously, the described embodiments are only a part of the embodiments of the present application, not all the embodiments. Based on the description of the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0028] In the description of the present application, unless otherwise explicitly specified and limited, the terms "arrangement", "installation", "connection" and the like should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or it can be integrally connected; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium. For those skilled in the art, the specific meaning of the above terms can be understood according to the specific circumstances.

[0029] The terms "up", "down", "left", "right", "front", "back", "top", "bottom", "inside", "outside" and the like indicate the orientation or positional relationship shown in the drawings, or the orientation or positional relationship commonly used when the product of the present application is used, and are only for the convenience of description and simplification of description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application.

[0030] The terms "first", "second", "third" and the like are only used to distinguish similar attributes of elements, and do not indicate or imply relative importance or a specific order.

[0031] The terms "comprise", "comprising", or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but can include other elements not expressly listed or inherent to such process, method, article, or apparatus.

[0032] The following will be described in detail through specific embodiments.

[0033] Embodiments of the utility model discloses a kind of focal plane full polarization perception devices, as shown in Figure 1 It includes substrate 1, phase delay layer 2 and polarization detection layer 3 are sequentially arranged on one side of substrate 1, and CCD sensor 4. Among them, phase delay layer 2 is used to carry out phase delay to incident light, so that incident light is modulated into polarized light of different angles.

[0034] Based on singular value decomposition of DOTP measurement matrix W of polarizer-rotating waveplate, the delay amount and azimuth angle of optimized phase delay layer 2 are obtained by minimizing the equal-weight variance of measurement matrix W. From the geometric point of view, each polarization state of the measurement corresponds to a point on the Poincare sphere, and the volume enclosed by them is proportional to the signal-to-noise ratio of the device, that is, the larger the volume, the larger the signal-to-noise ratio. Therefore, for the four measurement polarization states in the 2x2 micro-polarization array, they should form an inscribed tetrahedron in the Poincare sphere.

[0035] Specifically, as shown in Figures 2-3 Phase delay layer 2 has a plurality of arrayed phase delay regions 21, and each phase delay region 21 includes 2x2 pixel units 211. Each pixel unit 211 has a different fast-axis direction and can independently modulate the polarization state of incident light. Based on the array structure of phase delay layer 2 and the above principle, the fast-axis direction of the pixel units 211 of the phase delay region 21 is optimized, and the included angle between the fast-axis direction and the horizontal direction is in the range of ±13.1° to ±17.1° and ±49.7° to ±53.7°. Preferably, the included angle θ1=-51.7°, θ2=51.7°, θ3=-15.1°, and θ4=15.1° between the fast-axis direction and the horizontal direction. At the same time, when the phase delay amount satisfies the relationship 2π×0.36≤δ≤2π×0.37 (2π refers to the linear change of geometric phase from 0 to 2π), that is, the phase delay amount δ is in the range of 129.6° to 133.2°. Preferably, the phase delay amount is 132°, which can optimize the polarization state of incident light. At this time, the incident light is modulated into a specific elliptical polarized light.

[0036] In a feasible implementation manner, phase delay layer 2 is prepared by liquid crystal polymer molecular structure, which is a wide-band phase delay layer.

[0037] In this embodiment, as shown in Figures 4-5As shown, the polarization detection layer 3 adopts a single horizontal orientation, arranged as a double-layer grating structure, the polarization detection layer 3 screens linearly polarized light of a specific direction modulated by the phase delay layer 2, and light of other directions is blocked or attenuated.

[0038] The polarization detection layer 3 includes a high-transmittance substrate 31, a dielectric grating layer 32, and a metal grating layer 33. As shown, Figure 5 The dielectric grating layer 32 is arranged on the high-transmittance substrate 31; the metal grating layer 33 is arranged on the dielectric grating layer 32; the dielectric grating layer 32 and the metal grating layer 33 are arranged in the same direction, and together form a double-layer grating structure. Preferably, the high-transmittance substrate 31 is quartz, the dielectric grating layer 32 uses SiO2(silicon dioxide), and the metal grating layer 33 uses Al(aluminum). By adjusting the arrangement period, height, and width of the double-layer grating structure, the noise suppression capability can be improved.

[0039] The arrangement period P of the metal grating in the metal grating layer 33 is 140nm-180nm, the height H of the metal grating is 30nm-40nm, the width W of a single metal grating is 35nm-45nm, and the pixel size of a single metal grating is 100μm×100μm. The height h of the dielectric grating in the dielectric grating layer 32 is 80nm-90nm. Preferably, the arrangement period P of the metal grating is 160nm, the width W of a single metal grating is 40nm, and the height H of the metal grating is 30nm.

[0040] The array arrangement of the phase delay layer 2 and the single orientation arrangement of the polarization detection layer 3 are combined to form an elliptical polarization array, the vibration direction of a single metal grating corresponds to the angle between the fast axis direction of a pixel unit 211 in the phase delay layer 2 and the horizontal direction, thereby realizing detection of four optimized elliptical polarization states. Compared with a simple full-Stokes micro-polarization array, pixel-level repeated alignment in the manufacturing process is avoided, and the defect density of the micro-polarization array is reduced.

[0041] Each pixel unit on the CCD sensor 4 corresponds to a metal grating pixel size in the polarization detection layer, the CCD sensor 4 is used to receive light signals passing through the polarization detection layer and convert them into electrical signals, and by measuring the light intensity of different pixel units, the full-Stokes components are calculated.

[0042] In a feasible implementation, the working wavelength of the focal plane full-polarization perception device is 1000nm-3000nm.

[0043] In summary, the full focal surface full polarization sensing device can obtain full Stokes vector polarization information of the same target scene at one time, has simple structure, can realize real-time full polarization imaging, adopts four-pixel elliptical polarization principle to manufacture the metal wire grid polarization device, solves the single linear polarization collection problem, improves the detection efficiency, covers the practical wave band to the infrared wave band, expands the application range, and is suitable for being integrated into a small-sized device.

[0044] The above merely illustrates the specific implementation of the present application, but the protection scope of the present application is not limited to this, any skilled person in the art can easily think of changes or replacements within the technical range disclosed by the present application, which should be covered in the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the appended claims.

Claims

1. A focal plane splitting full polarization perception device, characterized in that, The device comprises a substrate, a phase delay layer and a polarization detection layer, the phase delay layer and the polarization detection layer are arranged on one side of the substrate, the phase delay layer has a plurality of arrayed phase delay regions, each phase delay region contains 2x 2 pixel units with different fast axis directions, and the phase delay layer modulates incident light into polarized light with different angles.

2. The epi-illumination, fully polarimetric-perceptive device of claim 1, wherein, The polarization detection layer is single horizontally oriented, and the phase delay layer and the polarization detection layer form an elliptical polarization array.

3. The epi-illumination, fully polarimetric-perceptive device of claim 1, wherein, The phase delay layer is a wide-band phase delay layer prepared from liquid crystal polymer molecular structure.

4. The epi-illumination, fully polarimetric-perceptive device of claim 1, wherein, The angle between the fast axis direction and the horizontal direction ranges from ±13.1° to ±17.1° and from ±49.7° to ±53.7°.

5. The epi-illumination, fully polarimetric-perceptive device of claim 1, wherein, The phase delay of the phase delay layer satisfies the formula: 2π×0.36≤δ≤2π×0.

37.

6. The epi-illumination, fully polarimetric-perceptive device of claim 1, wherein, The polarization detection layer is a double-layer wire grid structure, and the polarization detection layer screens linearly polarized light with specific direction modulated by the phase delay layer.

7. The epi-illumination, fully polarimetric-perceptive device of claim 6, wherein, The polarization detection layer comprises a high-transmittance substrate, a dielectric wire grid layer and a metal wire grid layer, the dielectric wire grid layer and the metal wire grid layer are arranged on the high-transmittance substrate in sequence, and the dielectric wire grid layer and the metal wire grid layer are arranged in the same direction.

8. The epi-illumination, fully polarimetric-perceptive device of claim 7, wherein, The arrangement period of the metal wire grid in the metal wire grid layer is 140-180 nm, and the height of the metal wire grid is 30-40 nm.

9. The epi-illumination, fully polarimetric-perceptive device of claim 7, wherein, The width of a single metal wire grid in the metal wire grid layer is 35-45 nm, and the pixel size of the single metal wire grid is 100 μm×100 μm.

10. The epi-illumination, fully polarimetric-perceptive device of claim 9, wherein, The pixels of the metal wire grid correspond to the pixels of the CCD sensor one by one.

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