Phase plate and infrared sensor

Abstract

The application provides a phase plate and an infrared sensor. The phase plate comprises a plurality of phase plate units, each of which comprises a plurality of structure units; each of the structure units comprises a substrate and a structure arranged thereon; the cross sections of the plurality of structures in the plurality of structure units in each of the phase plate units are sequentially increased or sequentially decreased; on the phase plate, at least two adjacent structures on one side with a larger cross section or on one side with a smaller cross section are combined into a combined structure, and the aspect ratio of the combined structure in each of the phase plate units is not more than a threshold aspect ratio. The phase plate provided by the application can cover a larger phase range, and has reduced processing difficulty and cost.

Description

Technical Field

[0001] This application relates to the field of optical technology, and in particular to a phase plate and an infrared sensor. Background Technology

[0002] A phase plate is an optical element commonly used in optical instruments such as spectrometers, lasers, optical microscopes, and sensors. Phase plates can disperse light beams into different wavelengths, enabling spectral analysis and wavelength selection. However, in related technologies, phase plate structures often have a large aspect ratio, making them difficult to manufacture and costly. Summary of the Invention

[0003] This application provides a phase plate and infrared sensor that reduce the difficulty of processing.

[0004] This application provides a phase plate, including: Multiple phase sheet units, each phase sheet unit including multiple structural units; each structural unit includes a substrate and a structure disposed thereon, the cross-sections of the multiple structures of the multiple structural units in each phase sheet unit increasing or decreasing sequentially; wherein, on the phase sheet, at least two adjacent structures located on the side with a large cross-section or on the side with a small cross-section are merged into a merged structure, and the aspect ratio of the merged structure in each phase sheet unit does not exceed an aspect ratio threshold.

[0005] Optionally, the center-to-center distance between two adjacent merged structures after merging is an integer multiple of the center-to-center distance between two adjacent structures before merging.

[0006] Optionally, the center-to-center distance between two adjacent merged structures located on the side with the larger cross-section is greater than the center-to-center distance between two adjacent structures before merging.

[0007] Optionally, the edge distance between two adjacent merged structures after merging is greater than the maximum value of the edge distance between two adjacent structures before merging.

[0008] Optionally, the side length of the merged structure located on the side with the smaller cross-section is greater than the maximum value of the side length of the structure before merging.

[0009] Optionally, the depth or height of the merged structure is the same as the depth or height of the structure before the merger.

[0010] Optionally, in each phase slice unit, the depth or height of two adjacent structures before merging are the same.

[0011] Optionally, the depth or height of the structure ranges from λ / 5 to 5λ, where λ represents the vacuum wavelength.

[0012] Optionally, in each phase slice unit, the structures of two adjacent structural units may be the same or different.

[0013] Optionally, the cross-section of the structure is a regular or irregular shape formed by straight edges, curved edges, or both straight and curved edges, or forms at least one connected region.

[0014] Optionally, the structural and substrate materials within the structural unit are one or a combination of silicon, silicon nitride, silicon carbide, titanium oxide, metal, indium tin oxide, germanium, chalcogenide glass, and niobium lithium oxide.

[0015] Optionally, the aspect ratio threshold of the silicon is greater than 4.

[0016] Optionally, the aspect ratio threshold of the silicon carbide, the metal, the titanium oxide, the indium tin oxide, the germanium, the chalcogenide glass, and the niobium lithium oxide is greater than 2.

[0017] Optionally, the aspect ratio threshold of the silicon nitride is greater than 3.

[0018] Optionally, the phase plate includes a plurality of nested sub-phase plates, the sub-phase plates including the structure before merging and the merged structure after merging; wherein, the outer sub-phase plate is located on the periphery of the inner sub-phase plate, and the area of ​​the outer sub-phase plate is larger than the area of ​​the inner sub-phase plate.

[0019] Optionally, the outline shape of the sub-phase piece is a regular shape or an irregular shape formed by straight edges, curved edges, or both straight and curved edges.

[0020] This application also provides an infrared sensor, including a phase plate as described in any of the above embodiments.

[0021] This application describes a phase sheet and an infrared sensor. The phase sheet includes multiple phase sheet units, and each phase sheet unit includes multiple structural units. Within each phase sheet unit, the cross-sections of the multiple structures within the structural units increase or decrease sequentially. The structure located on the side with the larger cross-section or the side with the smaller cross-section is merged with at least two adjacent or surrounding structures to form a merged structure. The aspect ratio of the merged structure in each phase sheet unit does not exceed an aspect ratio threshold. This configuration reduces manufacturing difficulty and cost while achieving coverage of a large phase range. Attached Figure Description

[0022] Figure 1 The diagram shown is a structural schematic of an embodiment of the phase slice before merging in this application.

[0023] Figure 2The diagram shown is a structural schematic of one embodiment of the merged phase slice of this application.

[0024] Figure 3 As shown Figure 2 A schematic diagram of the structure of one embodiment of the sub-phase sheet of the phase sheet shown.

[0025] Figure 4 As shown Figure 2 A schematic diagram of another embodiment of the sub-phase sheet of the phase sheet shown.

[0026] Figure 5 As shown Figure 2 A schematic diagram of another embodiment of the sub-phase plate of the phase plate shown.

[0027] Figure 6 The diagram shown is a structural schematic of one embodiment of the infrared sensor of this application.

[0028] Figure 7 As shown Figure 6 A schematic diagram of another embodiment of the infrared sensor is shown. Detailed Implementation

[0029] This application provides a phase plate and an infrared sensor. The phase plate and infrared sensor of this application will be described in detail below with reference to the accompanying drawings. Unless otherwise specified, the features of the following embodiments and implementations can be combined with each other.

[0030] Figure 1 The diagram shown is a structural schematic of an embodiment of the phase plate 10 before merging in this application. Figure 2 The diagram shown is a structural schematic of one embodiment of the merged phase plate 10 of this application. (In conjunction with...) Figure 1 and Figure 2 As shown, the phase plate 10 includes multiple phase plate units 11. Each phase plate unit 11 includes multiple structural units 12. The multiple structural units 12 are arranged along the X-axis or Y-axis, or in a centrally symmetrical, anti-centrally symmetrical, circular, or other arrangement. Each structural unit 12 includes a structure 121 and a substrate (not shown). The cross-sections of the multiple structures 121 within the multiple structural units 12 in each phase plate unit 11 increase or decrease sequentially. For example, the convex or concave cross-sections within the structural units 12 increase or decrease sequentially. Figure 1 As shown, the dimensions of the multiple structural units 121 in each phase plate unit 11 are arranged in descending order of size, or in ascending order of size (e.g., ...). Figure 1 (As shown).

[0031] exist Figure 2In the illustrated embodiment, in each phase slice unit 11, at least two adjacent structures 121 located on the side with the larger cross-section or the side with the smaller cross-section are merged into a merged structure 13. The shape and size of the merged structure can be the same as or different from the shape and size of the structure before merging. The aspect ratio of the merged structure 13 in each phase slice unit 11 does not exceed the aspect ratio threshold. In this embodiment, the maximum value of the ratio of the depth of structure 121 to the edge distance between two adjacent structures 121 or the ratio of the depth to the minimum side length of structure 121 is taken as the aspect ratio of structure 121. Both the aspect ratio and the aspect ratio threshold can be positive values. The aspect ratio is the actual aspect ratio of the merged structure 13 after merging. The aspect ratio threshold can be pre-configured, for example, it can be configured to 11. When the aspect ratio is greater than the aspect ratio threshold, it indicates that the aspect ratio of the merged structure 13 after merging is large, which makes processing difficult and costly. Therefore, this application ensures that the aspect ratio of the merged structure 13 after merging does not exceed 11, thereby reducing processing difficulty and cost while achieving coverage of a larger phase range.

[0032] exist Figure 2 In the illustrated embodiment, the spacing between two adjacent merged structures 13 after merging is greater than the spacing between structures 121 within two adjacent structural units 12 before merging. This reduces processing difficulty and cost. Figure 2 In the illustrated embodiment, on the phase plate, four adjacent structures on the side with the smaller cross-sectional area and the side with the larger cross-sectional area are merged. The center-to-center distance between two adjacent merged structures 13 after merging is an integer multiple of the center-to-center distance between two adjacent structures 121 before merging. For example, the center-to-center distance between two adjacent merged structures 13 after merging is twice the center-to-center distance between two adjacent structures 121 before merging. This reduces the aspect ratio of structure 121, thereby reducing processing difficulty and cost.

[0033] exist Figure 2 In the illustrated embodiment, the edge distance between two adjacent merged structures 13 located on the side with the larger cross-section is greater than the maximum value of the edge distance between two adjacent structures 121 before merging. Edge distance refers to the distance between the outermost edges of two adjacent structures 121. This reduces processing difficulty and cost. Figure 2 In the illustrated embodiment, the side length of the merged structure 13 located on the side with the smaller cross-section is greater than the maximum side length of the original structure 121. This reduces processing difficulty and cost.

[0034] exist Figure 2 In the illustrated embodiment, the depth or height of the merged structure 13 is the same as the depth or height of the original structure 121. This facilitates processing and reduces processing costs. Figure 2In the illustrated embodiment, in each phase slice unit 11, the depth or height of two adjacent structures 121 before merging are the same. This arrangement facilitates processing and reduces processing costs.

[0035] exist Figure 2 In the illustrated embodiment, the cross-sectional shape of the merged structure 13 is the same as that of the original structure 121; for example, both can be rectangular. In other embodiments, the cross-sectional shape of the merged structure 13 differs from that of the original structure 121. For example, the original structure 121 may be rectangular, while the merged structure 13 may be a regular or irregular shape such as an ellipse or a circle; no limitation is made in this application.

[0036] exist Figure 2 In the illustrated embodiment, the depth or height of structure 121 ranges from λ / 5 to 5λ, where λ represents the vacuum wavelength. If the depth of structure 121 is too large, a high aspect ratio (the ratio of the structure's height to its width) is required, which is detrimental to fabrication. If the depth of structure 121 is too small, it is difficult to cover a large phase range, making it difficult to meet design requirements. Therefore, this application sets the depth or width of structure 121 appropriately to facilitate fabrication and reduce fabrication costs. For example, the working center wavelength is 9550 nm, and the depth is 5.6 μm. Figure 2 In the illustrated embodiments, within each phase slice unit 11, the structures of two adjacent structures 121 may be the same or different. In some embodiments, the structures of two adjacent structures 121 within each phase slice unit 11 are the same. In other embodiments, the structures of two adjacent structures 121 within each phase slice unit 11 are different. In this embodiment, the structures of two adjacent structures 121 within each structural unit 12 are the same, and both are rectangular structures. This configuration reduces manufacturing difficulty and cost.

[0037] In some embodiments, the cross-section of structure 121 is a regular or irregular shape formed by straight edges, curved edges, or a combination of straight and curved edges, or forms at least one connected region. In this embodiment, the cross-section of structure 121 is a regular shape and a rectangular structure. This results in low processing difficulty and low cost. In other embodiments, the cross-section or shape of structure 121 can be other irregular shapes.

[0038] In some embodiments, the structure 121 and substrate material within structural unit 12 are one or a combination of silicon, silicon nitride, silicon carbide, titanium oxide, metal, indium tin oxide, germanium, chalcogenide glass, and niobium lithium oxide. In this embodiment, the structure 121 and substrate material within structural unit 12 are silicon. Silicon has good stability, an infrared window, and high infrared transmittance. In some embodiments, the aspect ratio threshold of silicon is greater than 4. This setting facilitates processing and reduces processing costs. In some embodiments, the aspect ratio threshold of silicon carbide, metal, titanium oxide, indium tin oxide, germanium, chalcogenide glass, and niobium lithium oxide is greater than 2. This setting facilitates processing and reduces processing costs. In some embodiments, the aspect ratio threshold of silicon nitride is greater than 3. This setting facilitates processing and reduces processing costs.

[0039] In some other embodiments, structure 121 may also be a subwavelength structure. A subwavelength structure refers to a periodic (or aperiodic) structure whose characteristic dimensions are comparable to or smaller than the operating wavelength. Because the characteristic dimensions of a subwavelength structure are smaller than the wavelength, its reflectivity, transmittance, polarization characteristics, and spectral characteristics exhibit distinctly different features from conventional optical elements. The subwavelength structure can be convex and / or concave. In some embodiments, the subwavelength structure can be convex. In other embodiments, the subwavelength structure can be concave. In still other embodiments, the subwavelength structure can be both convex and concave.

[0040] Figure 3 As shown Figure 2 This is a schematic diagram of one embodiment of the sub-phase sheet 14 of the phase sheet 10 shown. The phase sheet 10 includes a plurality of nested sub-phase sheets 14, each sub-phase sheet 14 including a pre-merging structure 121 and a post-merging structure 13. The outer sub-phase sheet 14 is located around the inner sub-phase sheet 14, and the area of ​​the outer sub-phase sheet 14 is greater than or equal to the area of ​​the inner sub-phase sheet 14. Figure 3 In the illustrated embodiment, the number of sub-phase slices 14 is at least two. The phase slice 10 includes a plurality of sub-phase slices 14, each sub-phase slice 14 including a first sub-phase slice 141 and a second sub-phase slice 142. The second sub-phase slice 142 is located around the periphery of the first sub-phase slice 141, and the area of ​​the second sub-phase slice 142 is larger than the area of ​​the first sub-phase slice 141. Figure 3In the illustrated embodiment, both the first sub-phase plate 141 and the second sub-phase plate 142 are rectangular structures. The area of ​​the first sub-phase plate 141 can be 0.2 square micrometers, and the area of ​​the second sub-phase plate 142 can be 0.8 square micrometers. The ratio of the length of the long side to the short side of this rectangular structure is less than 20. With this configuration, when a human body is located in front of the phase plate 10 and moves radially towards it, causing the object to move radially, the detector detects a significant change in signal. The small phase plate area results in high sensitivity, thus improving the radial monitoring sensitivity and monitoring distance of the phase plate 10 applied to the detector 30.

[0041] In this embodiment, structural unit 12 can be a metasurface structure with a substrate. The substrate provides support, and the substrate material does not absorb infrared wavelengths. The structure in the sub-phase sheet 14 can be a columnar structure. When infrared light is incident on the metasurface structure, different micro / nano structures placed at different positions introduce phase changes, superimposing additional phases on the original wavefront, thus altering the wavefront and expanding the phase range. By ensuring that the aspect ratio of the structure 121 in each phase sheet unit does not exceed the aspect ratio threshold, a larger phase range can be covered while reducing fabrication difficulty and cost.

[0042] In some embodiments, the area of ​​the outer sub-phase plate 14 is greater than or equal to the area of ​​the inner sub-phase plate. For example, the area of ​​the outer sub-phase plate 14 is at least twice the area of ​​the inner sub-phase plate 14. In some embodiments, the area of ​​the outer sub-phase plate 14 is twice or more the area of ​​the inner sub-phase plate 14. In some embodiments, the area of ​​the second sub-phase plate 142 is at least twice the area of ​​the first sub-phase plate 141. In some embodiments, the area of ​​the second sub-phase plate 142 is twice or more the area of ​​the first sub-phase plate 141. This configuration ensures that all objects to be tested located in front of and close to the detector 30 can be detected, resulting in a larger detection range and more accurate detection results.

[0043] In some embodiments, the shape or cross-section of the sub-phase piece 14 is a regular or irregular shape formed by straight edges, curved edges, or both straight and curved edges. For example, it includes, but is not limited to, an ellipse, a rectangle with right angles, and a rectangle with rounded corners. Figure 3 In the illustrated embodiment, the sub-phase sheet 14 has a regular rectangular shape. Both the first phase sheet 141 and the second phase sheet 142 have regular rectangular shapes. Furthermore, the geometric centers of the first phase sheet 141 and the second phase sheet 142 are the same. This arrangement facilitates processing and reduces processing costs.

[0044] In some embodiments, the sub-phase sheet 14 is made of one or a combination of silicon, silicon nitride, silicon carbide, titanium dioxide, metal, indium tin oxide, germanium, chalcogenide glass, and niobium lithium oxide. In some embodiments, the sub-phase sheet 14 is made of silicon, silicon nitride, silicon carbide, titanium dioxide, metal, indium tin oxide, germanium, chalcogenide glass, or niobium lithium oxide. In this embodiment, the sub-phase sheet 14 is made of silicon. Silicon has good stability.

[0045] Figure 4 As shown Figure 2 A schematic diagram of another embodiment of the sub-phase plate 14 of the phase plate 10 shown. Figure 4 The illustrated embodiments and Figure 3 Compared to the illustrated embodiment, the second sub-phase plate 142 can be elliptical in shape, and the first sub-phase plate 141 can be rectangular in shape. The geometric centers of the first sub-phase plate 141 and the second sub-phase plate 142 are not the same. Specifically, the geometric center of the second sub-phase plate 142 is lower than the geometric center of the first sub-phase plate 141.

[0046] Figure 5 As shown Figure 2 A schematic diagram of another embodiment of the sub-phase plate 14 of the phase plate 10 shown. Figure 5 The illustrated embodiments and Figure 3 Compared to the illustrated embodiment, the second sub-phase plate 142 can be a rounded rectangle, and the first sub-phase plate 141 can be an ellipse. The geometric centers of the first sub-phase plate 141 and the second sub-phase plate 142 are not the same. Specifically, the geometric center of the second sub-phase plate 142 is positioned slightly above the geometric center of the first sub-phase plate 141.

[0047] In some other embodiments, the shapes of the first sub-phase plate 141 and the second sub-phase plate 142 may also be other irregular shapes, and their geometric centers may be the same or different.

[0048] Figure 6 The diagram shown is a structural schematic of one embodiment of the infrared sensor 1 of this application. Figure 6 As shown, infrared sensor 1 is a sensor that uses infrared light for data processing. It is used for temperature sensing, gas composition analysis, and non-destructive testing, and is widely used in fields such as medicine, space technology, and environmental engineering. For example, using an infrared sensor to monitor the infrared light emitted by the human body can achieve monitoring and alarm functions for humans or animals, with advantages such as high sensitivity and fast response.

[0049] exist Figure 6In the illustrated embodiment, the infrared sensor 1 includes a phase plate 10, a housing 20, a detector 30, a filter 40 or a multilayer antireflective coating, and a lens 50. The detector 30 is disposed within the housing 20. The filter 40 or the multilayer antireflective coating is disposed as a window on the housing 20. The phase plate 10 is disposed within the housing 20 and located on the back side of the filter 40 or the multilayer antireflective coating, while the lens 50 is disposed outside the housing 20 and located in front of the filter 40 or the multilayer antireflective coating. In this embodiment, the phase plate 10 and the detector 30 are assembled within the housing 20, which serves a protective function. The phase plate 10 and the filter 40 or the multilayer antireflective coating are disposed on both sides of the housing 20. The filter 40 or the multilayer antireflective coating is assembled on the outer surface of the housing 20, and the phase plate 10 is assembled on the inner surface of the housing 20, which provides a fixed support function. The lens 50 is assembled outside the housing 20 and is spaced apart from the front of the filter 40 or the multilayer antireflective coating. The aforementioned housing 20 can be a metal housing, which can improve immunity to noise, temperature, and humidity.

[0050] exist Figure 6 In the illustrated embodiment, the detector 30 includes a first detection unit 31 and a second detection unit 32 separately disposed therefrom. In this embodiment, the first detection unit 31 and the second detection unit 32 can be a thermistor or a thermocouple. Figure 1 In the illustrated embodiment, the distance f between the lens 50 and the filter 40 or the multilayer antireflective coating ranges from 3mm to 30mm. The distance f between the lens 50 and the filter 40 or the multilayer antireflective coating can preferably be 3mm, 5mm, 10mm, 15mm, 20mm, 25mm, or 30mm. Setting a suitable distance between the lens 50 and the filter 40 or the multilayer antireflective coating can improve the transmittance of the lens 50 and reduce loss. Figure 6 In the illustrated embodiment, the filter 40 includes a silicon wafer 41 and a filter film 42 disposed on the surface of the silicon wafer 41. The filter film 42 transmits infrared light in the range of 8μm-11μm. The filter 40 utilizes the principles of absorption, interference, or diffraction to block light with wavelengths outside the 8μm-11μm range, while allowing light with wavelengths of 8μm-11μm to pass through. Figure 6 In the illustrated embodiment, the phase plate 10 is disposed on the back side of the silicon wafer. Figure 6 In the illustrated embodiment, the phase plate 10 is integrated with the silicon wafer 41. In other embodiments, the phase plate 10 is attached to the back surface of the silicon wafer 41. Figure 6 In the illustrated embodiment, the phase plate 10 is offset from the center of the detector 30 and is offset upwards relative to the center of the detector 30. That is, the phase plate 10 is offset upwards relative to the center of the silicon wafer 41 of the filter 40. In other embodiments, the phase plate 10 is offset from the center of the detector 30 and is offset downwards relative to the center of the detector 30. That is, the phase plate 10 is offset downwards relative to the center of the silicon wafer 41 of the filter 40. Figure 6In the illustrated embodiment, lens 50 is a Fresnel lens. Fresnel lenses can concentrate light, providing a wider range of infrared light for detector 30.

[0051] exist Figure 6 In the illustrated embodiment, the phase plate 10 is located in the front region of the detector 30. The phase plate 10 includes multiple phase plate units 11, and each phase plate unit 11 includes multiple structural units 12, each structural unit 12 including multiple sub-phase plates 14. Each sub-phase plate 14 includes a first sub-phase plate 141 and a second sub-phase plate 142. The second sub-phase plate 142 is located around the periphery of the first sub-phase plate 141, and the area of ​​the second sub-phase plate 142 is larger than the area of ​​the first sub-phase plate 141. Figure 6 In the illustrated embodiment, both the first sub-phase plate 141 and the second sub-phase plate 142 are rectangular structures. The ratio of the length of the long side to the length of the short side of the rectangular structure is less than 20.

[0052] The infrared sensor 1 of this application embodiment uses a phase plate 10 located in the area in front of the detector 30. The phase plate 10 is further configured with a first sub-phase plate 141 and a second sub-phase plate 142, with the second sub-phase plate 142 positioned around the first sub-phase plate 141 and its area larger than that of the first sub-phase plate 141. This configuration allows for a significant change in signal detected when a human body is positioned in front of the detector 30 and moves radially towards it. The small phase plate area results in high sensitivity, thus improving the radial detection sensitivity and detection distance of the detector 30.

[0053] In this embodiment, the infrared sensor 1 can be a thermal infrared sensor. When the object to be measured 2 is a human or animal, it emits infrared light of 8-12 micrometers. When this infrared light shines on the infrared sensor 1, it causes a change in the temperature of the surface of the infrared sensor 1. This temperature change affects the resistance value or potential difference of the thermistor or thermocouple, thereby generating an electrical signal. Traditional infrared sensor 1 uses a Fresnel lens that is hemispherical or planar, composed of several regions. Each small region can sense infrared radiation from different positions, thus capturing the infrared light of a human or animal moving at different positions. However, if the movement is radially toward a certain region of the Fresnel lens, it cannot be detected. In this embodiment, by etching N sub-phase slices onto a filter, a differential signal is generated when a human or animal moves perpendicular to the Fresnel lens, enabling the detection of the human or animal and triggering an alarm. The maximum number of alarms is N-1, and N can usually be set to 2, 3, or 4 depending on the required monitoring sensitivity. The infrared sensor 1 has advantages such as high sensitivity, high temporal resolution, and high spatial resolution. By setting the phase plate 10, detector 30, filter 40 or multilayer antireflection film and lens 50 as described above, when a human body is located in front of detector 30 and moves radially toward detector 30, the detector detects a significant change in signal when the object moves radially. The phase plate area is small and the sensitivity is high, thus improving the radial monitoring sensitivity and monitoring distance of detector 30.

[0054] exist Figure 6 In the embodiment shown, when the object under test is located in front of the infrared sensor 1 and beyond the first threshold distance, the image of the object under test falling on the phase plate 10 is located within the area of ​​the first sub-phase plate 141; wherein, the first threshold distance is the distance between the object under test and the phase plate 10 and the lens 50 that triggers the alarm.

[0055] In some embodiments, the first sub-phase plate 141 acts on the object to be tested facing the infrared sensor 1 and located outside a threshold. When the object to be tested is in front of the infrared sensor 1 and outside the threshold, as it moves from a direction away from the infrared sensor 1 toward a direction closer to the infrared sensor 1, the image detected by the infrared sensor 1 gradually increases in size, and the area of ​​the image does not exceed the area of ​​the first sub-phase plate 141. In this embodiment, the threshold can be configured to 6 meters. That is, the first sub-phase plate 141 acts on the object to be tested facing the infrared sensor 1 and located more than 6 meters away (e.g., 13 meters away). When the object to be tested moves closer to the infrared sensor 1 from a position more than 6 meters away, the image detected by the infrared sensor 1 gradually increases in size so that it can be fully detected by the first sub-phase plate 141. This allows the detection of the object to be tested in that direction, and by increasing the size of the detected image, the detection becomes more obvious and accurate.

[0056] exist Figure 6In the embodiment shown, when the object to be tested is located in front of the infrared sensor 1 and within the first threshold distance, the imaging area of ​​the object to be tested falling on the phase plate 10 does not exceed the area of ​​the second sub-phase plate 142.

[0057] In some embodiments, the second sub-phase plate 142 acts on the object to be tested facing the infrared sensor 1 and within a threshold. When the object to be tested is in front of the infrared sensor 1 and within the threshold, as it moves from a direction away from the infrared sensor 1 towards a direction closer to the infrared sensor 1, the image detected by the infrared sensor 1 gradually decreases in size, and the area of ​​this image does not exceed the area of ​​the second sub-phase plate 142. In this embodiment, the threshold can be configured to 6 meters. That is, the second sub-phase plate 142 acts on the object to be tested facing the infrared sensor 1 and within 6 meters. When a person approaches the infrared sensor 1 from a position greater than 6 meters away, the image detected by the infrared sensor 1 gradually decreases in size so that it can be fully detected by the second sub-phase plate 142. This allows for the detection of people in that direction, and by increasing the size of the detected image, the detection becomes more obvious and accurate.

[0058] exist Figure 6 In the illustrated embodiment, when the object to be measured is located in front of and approaches the infrared sensor 1, the first sub-phase plate 141 and the second sub-phase plate 142 apply deflection directions to the light in opposite directions. This arrangement results in a significant energy change during detection and high sensitivity.

[0059] exist Figure 6 In the illustrated embodiment, when the object under test is located in front of and close to the infrared sensor 1, the angle between the deflection directions applied to the light by the first sub-phase plate 141 and the second sub-phase plate 142 ranges from 30° to 150°. In some embodiments, when the object under test is located in front of and close to the infrared sensor 1, the angle between the deflection directions applied to the light by the first sub-phase plate 141 and the second sub-phase plate 142 is 30°, 60°, 90°, 120°, or 150°. This configuration makes the change in detection energy significant and provides high sensitivity.

[0060] Figure 7 As shown Figure 6 A schematic diagram of another embodiment of the infrared sensor 1 shown. Figure 7 The illustrated embodiments and Figure 6 The illustrated embodiment is similar, with the main difference being that the phase plate 10 is located at the center of the detector 30. That is, the phase plate 10 is not offset relative to the center of the detector 30. This arrangement reduces the manufacturing complexity without affecting the detection range.

[0061] The infrared sensor 1 of this application is configured as described above. Figures 2 to 5The phase plate 10 shown in the embodiment can detect not only people passing through the detection range, but also people moving towards the detector 30, offering rich functionality and adaptability to various scenarios.

[0062] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of protection of this application.

Claims

1. A phase plate, characterized in that, include: Multiple phase sheet units, each phase sheet unit including multiple structural units; each structural unit includes a substrate and a structure disposed thereon, the cross-sections of the multiple structures within the multiple structural units in each phase sheet unit increasing or decreasing sequentially; wherein, on the phase sheet, at least two adjacent structures located on the side with a larger cross-section or the side with a smaller cross-section are merged into a merged structure, and the aspect ratio of the merged structure in each phase sheet unit does not exceed an aspect ratio threshold.

2. The phase plate according to claim 1, characterized in that, The center-to-center distance between two adjacent structures after merging is an integer multiple of the center-to-center distance between two adjacent structures before merging; and / or The center-to-center distance between two adjacent merged structures after merging is greater than the center-to-center distance between two adjacent structural units before merging.

3. The phase plate according to claim 1, characterized in that, The edge distance between two adjacent merged structures located on the side with the larger cross-section is greater than the maximum edge distance between two adjacent structures before merging; or The side length of the merged structure located on the side with the smaller cross-section is greater than the maximum side length of the original structure.

4. The phase plate according to claim 1, characterized in that, The depth or height of the merged structure is the same as the depth or height of the structure before the merger; and / or In each phase slice unit, the depth or height of two adjacent structures before merging are the same; and / or The depth or height of the structure ranges from λ / 5 to 5λ, where λ represents the vacuum wavelength.

5. The phase plate according to claim 1, characterized in that, In each phase slice unit, the structures of two adjacent structures are the same or different; and / or The cross-section of the structure is a regular or irregular shape formed by straight edges, curved edges, or both straight and curved edges, or forms at least one connected region.

6. The phase plate according to claim 1, characterized in that, The structural and substrate materials within the structural unit are one or a combination of silicon, silicon nitride, silicon carbide, titanium dioxide, metal, indium tin oxide, germanium, chalcogenide glass, and niobium lithium oxide.

7. The phase plate according to claim 6, characterized in that, The aspect ratio threshold of the silicon is greater than 4; or The aspect ratio threshold of the silicon carbide, the metal, the titanium oxide, the indium tin oxide, the germanium, the chalcogenide glass, and the niobium lithium oxide is greater than 2; or The aspect ratio threshold of the silicon nitride is greater than 3.

8. The phase plate according to claim 1, characterized in that, The phase plate includes multiple nested sub-phase plates, each sub-phase plate including the structure before merging and the merged structure after merging; wherein, the outer sub-phase plate is located around the inner sub-phase plate, and the area of ​​the outer sub-phase plate is larger than the area of ​​the inner sub-phase plate.

9. The phase plate according to claim 8, characterized in that, The outline shape of the sub-phase piece is a regular or irregular shape formed by straight edges, curved edges, or both straight and curved edges.

10. An infrared sensor, characterized in that, Includes the phase plate as described in any one of claims 1 to 9.

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