Infrared narrow-band optical filter with working wave band of 3900-4100nm

Abstract

The utility model discloses an infrared narrowband optical filter with a working wave band of 3900-4100nm, the infrared narrowband optical filter comprises a substrate, a main film system and a secondary film system, the main film system is arranged on a first side of the substrate, the secondary film system is arranged on a second side of the substrate, the second side is opposite to the first side, the main film system is arranged on the first side, and the secondary film system is arranged on the second side of the substrate. The main film system comprises 26 high-refractive-index film layers and low-refractive-index film layers which are alternately overlaid outwards from the substrate according to the structure of the main film system, and the secondary film system comprises 38 high-refractive-index film layers and low-refractive-index film layers which are alternately overlaid outwards from the substrate according to the structure of the secondary film system. The infrared narrow-band optical filter can have a good light transmission effect within the wavelength range of 3900-4100 nm, the average transmittance is larger than 94%, the infrared narrow-band optical filter is highly cut off within the wave bands of 1000-3700 nm and 4300-6500 nm, the average transmittance is smaller than 1%, stray light interference can be effectively reduced, and the sensitivity and the detection efficiency of an infrared detector are improved.

Description

Technical Field

[0001] The utility model relates to an infrared filter, in particular to an infrared narrow-band filter with a working band of 3900-4100nm. Background Art

[0002] Optical bandpass filter is a very important optical equipment component. Its main function is to divide the spectrum within a certain range into two parts. One part that does not allow light to pass is called the cutoff area, and the other part that requires light to pass fully is called the bandpass area. Bandpass filters play a very important role in various optical systems. Infrared bandpass filters are mainly used in infrared spectrum detection systems. They have the function of filtering out background clutter, which is of great significance to improving the signal-to-noise ratio and improving the performance of optical systems. They have very important applications in the aerospace and military fields. However, in the existing technology, infrared detection products in the 3900~4100nm band cannot meet the requirements of high anti-interference ability. Utility Model Content

[0003] The utility model provides an infrared narrowband filter with a working band of 3900-4100nm, which can have a good light transmission effect in the wavelength range of 3900~4100nm, with an average transmittance of more than 94%, and is highly cut off in the bands of 1000~3700nm and 4300~6500nm, with an average transmittance of less than 1%, which can effectively reduce stray light interference and improve the sensitivity and detection efficiency of infrared detectors.

[0004] In order to achieve the above object, the embodiment of the utility model adopts the following technical solution:

[0005] An infrared narrowband filter with a working band of 3900-4100nm, comprising a substrate, a main film system and a secondary film system, wherein the main film system is located on a first side of the substrate, the secondary film system is located on a second side of the substrate, the second side is opposite to the first side, the main film system comprises 26 layers of high refractive index film layers and low refractive index film layers alternately stacked from the substrate to the outside according to the main film system structure, and the main film system structure is:

[0006] substrate / 100 nmH, 786.33 nmL, 247.44 nmH, 730.72 nmL, 269.61 nmH, 642.93 nmL, 388.17 nmH, 925.68 nmL, 378.28 nmH, 602.78 nmL, 308.84 nmH, 584.78 nmL, 301.77 nmH, 583.14 nmL, 301.44 nmH, 573.49 nmL, 304.07 nmH, 587.88 nmL, 295.56 nmH, 601.25 nmL, 328.8 nmH, 1415.12 nmL, 330.53 nmH, 683.61 nmL, 215.64 nmH, 381.68 nmL / air;

[0007] The secondary film system includes 38 layers of high refractive index film layers and low refractive index film layers alternately stacked from the base to the outside according to the secondary film system structure. The secondary film system structure is:

[0008] Base / 100nmH, 210.33nmmL, 120.6nmH, 246.09nmmL, 105.37nmH, 135.38nmmL, 127.32nmH, 248.93nmmL, 81.07nmH, 157nmmL, 133.05nmH, 249.17nmmL, 131.32nmH, 203.37nmmL, 101.25nmH, 235.05nmmL, 148.67nmH, 331.03nmmL, 160.16nmH, 24 7.28 nmL, 111.66 nmH, 167.45 nmL, 122.61 nmH, 377.5 nmL, 153.88 nmH, 319.51 nmL, 186.2 nmH, 303.64 nmL, 196.3 nmH, 308.72 nmL, 247.93 nmH, 248.6 nmL, 164.45 nmH, 354.36 nmL, 170.23 nmH, 352.67 nmL, 165.95 nmH, 602.47 nmL / air;

[0009] Among them, H represents a high refractive index film layer, L represents a low refractive index film layer, and the thickness of H and L is the thickness of the film layer.

[0010] According to one aspect of the present invention, the main film system and the secondary film system are generated by a physical vapor deposition method.

[0011] According to one aspect of the present invention, the substrate is a germanium substrate.

[0012] According to one aspect of the utility model, the high refractive index film layer is a germanium film layer, and the low refractive index film layer is a zinc sulfide film layer.

[0013] According to one aspect of the utility model, the germanium film layer is coated by physical vapor deposition using electron gun evaporation.

[0014] According to one aspect of the utility model, the zinc sulfide film layer is physically vapor deposited by thermal evaporation using a resistance boat.

[0015] According to one aspect of the present invention, the refractive index of the high refractive index film layer is greater than 3.

[0016] According to one aspect of the utility model, the infrared narrow-band filter with a working band of 3900-4100 nm has an average transmittance greater than 94% within the wavelength range of 3900~4100 nm.

[0017] According to one aspect of the utility model, the infrared narrowband filter with a working band of 3900-4100nm has an average transmittance of less than 1% in the wavelength ranges of 1000~3700nm and 4300~6500nm.

[0018] Advantages of the implementation of the utility model: the utility model provides an infrared narrow-band filter with a working band of 3900-4100nm, a spectral range of the passband area of ​​3900~4100nm, and an average transmittance of >94%; the spectral range of the cut-off area is 1000~3700nm and 4300~6500nm, and the average transmittance is <1%, which can well improve the signal-to-noise ratio, enhance the signal strength, and improve the detector response rate; it can be used in various infrared optical detection systems to reduce the influence of background clutter, enhance the signal strength, and improve the detector response and resolution. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0020] Figure 1 This is a schematic diagram of the structure of an infrared narrow-band filter with a working band of 3900-4100nm described in the utility model;

[0021] Figure 2 This is the spectral transmittance curve of the main film system of the infrared narrow-band filter with a working band of 3900-4100nm.

[0022] Figure 3 This is the spectral transmittance curve of the infrared narrow-band filter sub-film system with a working band of 3900-4100nm.

[0023] Figure 4 This is the spectral transmittance curve of the infrared narrow-band filter with a working band of 3900-4100nm. DETAILED DESCRIPTION

[0024] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0025] Embodiment 1

[0026] like Figure 1 , Figure 2 , Figure 3 and Figure 4 As shown, an infrared narrowband filter with a working band of 3900-4100nm, the working band range is 3900~4100nm, the selected central wavelength is 4000nm, including a substrate 2, a main film system 1 and a secondary film system 3, the main film system is located on the first side of the substrate, the secondary film system is located on the second side of the substrate, the second side is opposite to the first side, the main film system and the secondary film system described in this embodiment are multi-layer film irregular film system structures, the main film system includes high refractive index film layers and low refractive index film layers alternately stacked from the substrate to the outside according to the main film system structure, a total of 26 layers, the main film system structure is:

[0027] substrate / 100 nmH, 786.33 nmL, 247.44 nmH, 730.72 nmL, 269.61 nmH, 642.93 nmL, 388.17 nmH, 925.68 nmL, 378.28 nmH, 602.78 nmL, 308.84 nmH, 584.78 nmL, 301.77 nmH, 583.14 nmL, 301.44 nmH, 573.49 nmL, 304.07 nmH, 587.88 nmL, 295.56 nmH, 601.25 nmL, 328.8 nmH, 1415.12 nmL, 330.53 nmH, 683.61 nmL, 215.64 nmH, 381.68 nmL / air;

[0028] The secondary film system includes high refractive index film layers and low refractive index film layers alternately stacked from the base to the outside according to the secondary film system structure, totaling 38 layers. The secondary film system structure is:

[0029] Base / 100nmH, 210.33nmmL, 120.6nmH, 246.09nmmL, 105.37nmH, 135.38nmmL, 127.32nmH, 248.93nmmL, 81.07nmH, 157nmmL, 133.05nmH, 249.17nmmL, 131.32nmH, 203.37nmmL, 101.25nmH, 235.05nmmL, 148.67nmH, 331.03nmmL, 160.16nmH, 24 7.28 nmL, 111.66 nmH, 167.45 nmL, 122.61 nmH, 377.5 nmL, 153.88 nmH, 319.51 nmL, 186.2 nmH, 303.64 nmL, 196.3 nmH, 308.72 nmL, 247.93 nmH, 248.6 nmL, 164.45 nmH, 354.36 nmL, 170.23 nmH, 352.67 nmL, 165.95 nmH, 602.47 nmL / air;

[0030] Wherein, H represents a high refractive index film layer, L represents a low refractive index film layer, and the thickness of the film layer is H and L. In practical applications, the substrate may be a transparent film, including but not limited to glass, silicon substrate, germanium substrate, etc.

[0031] In this embodiment, the main film system and the secondary film system can be formed by a physical vapor deposition method.

[0032] In practical applications, the refractive index of the high refractive index film layer is greater than 3.

[0033] In this embodiment, the infrared narrowband filter with a working band of 3900-4100nm is used to measure the optical properties of the film using an infrared Fourier spectrometer. The spectral curve corresponding to the main film system on the front side is shown in FIG. Figure 2 , the spectral curve corresponding to the back secondary film system can be found in Figure 3 , the spectral curve of the filter after double-sided coating can be found in Figure 4 , achieving an average transmittance greater than 94% in the wavelength range of 3900~4100nm; and an average transmittance less than 1% in the wavelength ranges of 1000~3700nm and 4300~6500nm.

[0034] The infrared narrowband filter with a working band of 3900-4100nm described in this embodiment has an average transmittance greater than 94% in the wavelength range of 3900~4100nm; and an average transmittance less than 1% in the wavelength range of 1000~3700nm and 4300~6500nm. It can well improve the signal-to-noise ratio, enhance the signal strength, and improve the detector response rate; it can be used in various infrared optical detection systems to reduce the influence of background clutter, enhance the signal strength, and improve the detector response and resolution.

[0035] Embodiment 2

[0036] like Figures 1 to 4 As shown, an infrared narrowband filter with a working band of 3900-4100nm, the working band range is 3900~4100nm, including a germanium substrate, a main film system 1 and a secondary film system 3, the main film system and the secondary film system are generated by a physical vapor deposition method, the main film system is located on the first side of the germanium substrate, the secondary film system is located on the second side of the germanium substrate, the second side is opposite to the first side, the main film system includes germanium film layers and zinc sulfide film layers alternately stacked from the germanium substrate to the outside according to the main film system structure, a total of 26 layers, the main film system structure is:

[0037] Germanium substrate / 100nmH, 786.33nmL, 247.44nmH, 730.72nmL, 269.61nmH, 642.93nmL, 388.17nmH, 925.68nmL, 378.28nmH, 602.78nmL, 308.84nmH, 584.78nmL, 301.77nmH, 583.14nmL, 301.44nmH, 573.49nmL, 304.07nmH, 587.88nmL, 295.56nmH, 601.25nmL, 328.8nmH, 1415.12nmL, 330.53nmH, 683.61nmL, 215.64nmH, 381.68nmL / air;

[0038] The sub-film system includes germanium film layers and zinc sulfide film layers alternately stacked from the germanium substrate outward according to the sub-film system structure, a total of 38 layers, and the sub-film system structure is:

[0039] Germanium substrate / 100nmH, 210.33nmL, 120.6nmH, 246.09nmL, 105.37nmH, 135.38nmL, 127.32nmH, 248.93nmL, 81.07nmH, 157nmL, 133.05nmH, 249.17nmL, 131.32nmH, 203.37nmL, 101.25nmH, 235.05nmL, 148.67nmH, 331.03nmL, 160.16nmH, 2 47.28 nmL, 111.66 nmH, 167.45 nmL, 122.61 nmH, 377.5 nmL, 153.88 nmH, 319.51 nmL, 186.2 nmH, 303.64 nmL, 196.3 nmH, 308.72 nmL, 247.93 nmH, 248.6 nmL, 164.45 nmH, 354.36 nmL, 170.23 nmH, 352.67 nmL, 165.95 nmH, 602.47 nmL / air;

[0040] Wherein, H represents the germanium film layer, L represents the zinc sulfide film layer, and the value before H and L is the thickness of the film layer.

[0041] In this embodiment, the germanium film layer is physically vapor deposited by electron gun evaporation, and the zinc sulfide film layer is physically vapor deposited by resistance boat thermal evaporation.

[0042] The refractive index of the germanium film layer is greater than 3.

[0043] In this embodiment, the infrared narrowband filter with a working band of 3900-4100nm is used to measure the optical properties of the film using an infrared Fourier spectrometer. The spectral curve corresponding to the main film system on the front side is shown in FIG. Figure 2 , the spectral curve corresponding to the back secondary film system can be found in Figure 3 , the spectral curve of the filter after double-sided coating can be found in Figure 4 , achieving an average transmittance greater than 94% in the wavelength range of 3900~4100nm; and an average transmittance less than 1% in the wavelength ranges of 1000~3700nm and 4300~6500nm.

[0044] The infrared narrowband filter with a working band of 3900-4100nm described in this embodiment has an average transmittance greater than 94% in the wavelength range of 3900~4100nm; and an average transmittance less than 1% in the wavelength range of 1000~3700nm and 4300~6500nm. It can well improve the signal-to-noise ratio, enhance the signal strength, and improve the detector response rate; it can be used in various infrared optical detection systems to reduce the influence of background clutter, enhance the signal strength, and improve the detector response and resolution.

[0045] The above is only a specific implementation of the utility model, but the protection scope of the utility model is not limited thereto. Any changes or substitutions that can be easily thought of by any technician familiar with the technical field within the technical scope disclosed in the utility model should be included in the protection scope of the utility model. Therefore, the protection scope of the utility model shall be based on the protection scope of the claims.

Claims

1. An infrared narrowband filter with a working band of 3900-4100nm, comprising a substrate, a main film system and a secondary film system, wherein the main film system is located on a first side of the substrate, and the secondary film system is located on a second side of the substrate, the second side is opposite to the first side, and characterized in that: The main film system includes 26 layers of high refractive index film layers and low refractive index film layers alternately stacked from the base to the outside according to the main film system structure. The main film system structure is: substrate / 100 nmH, 786.33 nmL, 247.44 nmH, 730.72 nmL, 269.61 nmH, 642.93 nmL, 388.17 nmH, 925.68 nmL, 378.28 nmH, 602.78 nmL, 308.84 nmH, 584.78 nmL, 301.77 nmH, 583.14 nmL, 301.44 nmH, 573.49 nmL, 304.07 nmH, 587.88 nmL, 295.56 nmH, 601.25 nmL, 328.8 nmH, 1415.12 nmL, 330.53 nmH, 683.61 nmL, 215.64 nmH, 381.68 nmL / air; The secondary film system includes 38 layers of high refractive index film layers and low refractive index film layers alternately stacked from the base to the outside according to the secondary film system structure. The secondary film system structure is: Base / 100nmH, 210.33nmmL, 120.6nmH, 246.09nmmL, 105.37nmH, 135.38nmmL, 127.32nmH, 248.93nmmL, 81.07nmH, 157nmmL, 133.05nmH, 249.17nmmL, 131.32nmH, 203.37nmmL, 101.25nmH, 235.05nmmL, 148.67nmH, 331.03nmmL, 160.16nmH, 24 7.28 nmL, 111.66 nmH, 167.45 nmL, 122.61 nmH, 377.5 nmL, 153.88 nmH, 319.51 nmL, 186.2 nmH, 303.64 nmL, 196.3 nmH, 308.72 nmL, 247.93 nmH, 248.6 nmL, 164.45 nmH, 354.36 nmL, 170.23 nmH, 352.67 nmL, 165.95 nmH, 602.47 nmL / air; Among them, H represents a high refractive index film layer, L represents a low refractive index film layer, and the thickness of H and L is the thickness of the film layer.

2. The infrared narrowband filter with a working band of 3900-4100 nm according to claim 1, characterized in that: The main film system and the secondary film system are generated by a physical vapor deposition method.

3. The infrared narrowband filter with a working band of 3900-4100 nm according to claim 1, characterized in that: The substrate is a germanium substrate.

4. The infrared narrowband filter with a working band of 3900-4100 nm according to claim 1, characterized in that: The high refractive index film layer is a germanium film layer, and the low refractive index film layer is a zinc sulfide film layer.

5. The infrared narrowband filter with a working band of 3900-4100 nm according to claim 4, characterized in that: The germanium film layer is coated by physical vapor deposition using an electron gun evaporation method.

6. The infrared narrowband filter with a working band of 3900-4100 nm according to claim 4, characterized in that: The zinc sulfide film layer is physically vapor deposited by thermal evaporation in a resistance boat.

7. The infrared narrowband filter with a working band of 3900-4100 nm according to claim 1, characterized in that: The refractive index of the high refractive index film layer is greater than 3.

8. The infrared narrowband filter with a working band of 3900-4100 nm according to any one of claims 1 to 7, characterized in that: The infrared narrow-band filter with a working band of 3900-4100nm has an average transmittance greater than 94% within the wavelength range of 3900~4100nm.

9. The infrared narrowband filter with a working band of 3900-4100 nm according to any one of claims 1 to 7, characterized in that: The infrared narrow-band filter with a working band of 3900-4100 nm has an average transmittance of less than 1% within the wavelength ranges of 1000-3700 nm and 4300-6500 nm.

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