An ultrathin dichroic mirror

Abstract

The utility model discloses a kind of ultra-thin two-way dichroic mirror, the ultra-thin two-way dichroic mirror is no base in light aperture area, only one layer of membrane system structure, total thickness 3.1-3.2 μm of film, film material is composed of titanium dioxide (TiO2) and silicon dioxide (SiO2), in 450nm-800nm wavelength range, when working angle 45°, reflectivity>92%, in 1700nm-3400nm wavelength range, transmissivity>92%.The ultra-thin two-way dichroic mirror is under self weight state, in 243.15K-328.15K temperature range, maximum stress <10^6pa, maximum deformation <10^‑3 μm, under 3g acceleration impact, the order of magnitude of maximum stress and maximum deformation is still consistent with the aforementioned, without big change.The preparation method of the ultra-thin two-way dichroic mirror includes gluing, coating, stripping process.The ultra-thin two-way dichroic mirror removes base, realizes ultra-thin film spectrometer, to reduce wave aberration, improve imaging quality.

Description

Technical Field

[0001] This utility model relates to the field of geometric optics and micro / nano optics design and manufacturing technology, and in particular to an ultrathin dichroic mirror. Background Technology

[0002] Hyperspectral imaging technology, as a key means of Earth remote sensing and target detection, can simultaneously acquire the geometric shape, radiation characteristics, and spectral information of a target. In numerous fields, including continuous monitoring of the ecological environment, detailed surveys of natural resources, real-time monitoring of disasters, precise development of agriculture, forestry, animal husbandry, and fisheries, and rational urban planning, it is demonstrating its increasingly important and irreplaceable role, providing strong technical support and data assurance for scientific decision-making and efficient management in various sectors.

[0003] A dichroic mirror is an optical element based on multilayer optical coating technology that can split light by selectively reflecting and transmitting different wavelengths. Its core principle is to achieve high reflectivity for specific wavelengths of light while maintaining high transmittance for other wavelengths through thin-film interference effects.

[0004] In hyperspectral applications, dichroic mirrors are mainly used in spectrometers to acquire information across multiple broad spectral bands. By separating light of different wavelengths (such as separating visible and infrared light), the spectrometer can simultaneously detect spectral information in multiple bands.

[0005] Traditional dichroic mirrors, due to technical limitations, typically have a substrate in the light-transmitting aperture area. However, the substrate has a certain thickness, and the transmitted light will introduce wave phase difference, affecting the image quality of the imaging system. Summary of the Invention

[0006] To address the aforementioned problems in the existing technology, this invention provides an ultrathin dichroic mirror with a substrate-free aperture area. However, the substrate-free design of the ultrathin dichroic mirror, with only one thin film suspended in the air, presents challenges to the fabrication method. Therefore, this invention also provides a fabrication method for the ultrathin dichroic mirror, which can effectively improve the wavefront aberration problem caused by traditional dichroic mirrors and enhance imaging quality.

[0007] To achieve the above objectives, the technical solution adopted by this utility model is as follows:

[0008] The first objective of this invention is to provide an ultrathin dichroic mirror, the technical point of which is that the dichroic mirror is a thin film with a thickness of 3.1-3.2 μm, the thin film is composed of alternating titanium dioxide layers and silicon dioxide layers, the bottom layer of the thin film is a silicon dioxide layer, and the light transmission aperture area of ​​the ultrathin dichroic mirror has no substrate.

[0009] To better achieve the above solution, the ultrathin dichroic mirror of this invention has a total of 37 layers of titanium dioxide and silicon dioxide.

[0010] To better achieve the above solution, the basic film system of the thin film layer in the ultrathin dichroic mirror of this invention is |(0.5HL 0.5H)^6 (0.4H 0.8L 0.4H)^5 (0.3H 0.6L 0.3H)^5|Air, where Air is air, H is TiO2, L is SiO2, and the designed wavelength is 1200nm.

[0011] To better achieve the above solution, the final structure of the film system in the ultrathin dichroic mirror of this invention is as follows: | 0.1487H 0.1191L 0.1952H 0.8586L 0.6725H 0.8193L 0.7918H 0.7957L 0.7386H 0.7255L 0.6954H 0.7086L 0.6778H 0.6786L 0.5569H 0.4965L 0.4973H 0.5962L 0.6065H 0.5852L 0.5058H 0.4796L 0.4553H 0.4256L 0.479H 0.3821L 0.4024H 0.4009L 0.47H 0.3339L 0.3203H 0.3322L 0.2678H 0.3529L 0.2133H 0.3872L 0.2214H|Air.

[0012] To better achieve the above solution, the ultrathin dichroic mirror of this invention has a reflectivity of >92% in the 450-800nm ​​spectral range and a transmittance of >92% in the 1700-3400nm spectral range.

[0013] To better achieve the above solution, the working angle of the ultrathin dichroic mirror of this invention is 45°.

[0014] To better achieve the above solution, the dimensions of the ultra-thin dichroic mirror of this utility model include, but are not limited to, 32mm × 32mm.

[0015] To better achieve the above solution, the ultrathin dichroic mirror of this invention, under its own weight, has a maximum stress of <10^6 Pa and a maximum deformation of <10^-3 μm when the temperature range is 243.15 K - 328.15 K.

[0016] Compared with the prior art, the present invention has the following beneficial effects:

[0017] 1. The ultrathin dichroic mirror of this utility model is based on the design principle of long-pass interference cutoff filter. It uses titanium dioxide (TiO2) and silicon dioxide (SiO2) as high and low refractive index materials, respectively. In the wavelength range of 450-800nm, the reflectivity is >92% and in the wavelength range of 1700-3400nm, the transmittance is >92%.

[0018] 2. The preparation method of this ultrathin dichroic mirror adopts the processes of coating (coating and spin coating), coating (magnetron sputtering), and peeling. The prepared sample has strong stability, is not easily deformed, and is resistant to high temperatures. Compared with traditional dichroic mirrors, this invention is thinner and can be used in spectrometers, improving the wavefront aberration problem of traditional dichroic mirrors and enhancing imaging quality. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the ultrathin dichroic mirror film structure in this embodiment;

[0020] Figure 2 This is the reflectance and transmittance curve of the ultrathin dichroic mirror in this embodiment within the 450-800nm ​​spectral range;

[0021] Figure 3 This is the reflectance and transmittance curve of the ultrathin dichroic mirror in this embodiment within the 1700-3400nm spectral range;

[0022] Figure 4 This embodiment describes the structure of the ultra-thin dichroic mirror adhesive coating fixture base;

[0023] Figure 5 This embodiment features an ultra-thin dichroic mirror coating tooling silicone pad structure.

[0024] Figure 6 This embodiment is the ultra-thin dichroic mirror coating tooling frame structure;

[0025] Figure 7 This is a flowchart of the development process of the ultrathin dichroic mirror in this embodiment.

[0026] 1- Bottom surface, 2- First screw hole, 3- Protruding structure; 4- Silicone square frame, 5- Second screw hole; 6- Stainless steel square frame, 7- Third screw hole. Detailed Implementation

[0027] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0028] like Figure 1As shown, this invention uses titanium dioxide (TiO2) and silicon dioxide (SiO2) as high and low refractive index materials, respectively. The basic structure of the film layer is: |(0.5HL 0.5H)^6 (0.4H 0.8L 0.4H)^5 (0.3H 0.6L 0.3H)^5|Air. The final film system structure is as follows: | 0.1487H 0.1191L 0.1952H 0.8586L 0.6725H 0.8193L 0.7918H 0.7957L 0.7386H 0.7255L 0.6954H 0.7086L 0.6778H 0.6786L 0.5569H 0.4965L 0.4973H 0.5962L 0.6065H 0.5852L 0.5058H 0.4796L 0.4553H 0.4256L 0.479H 0.3821L 0.4024H 0.4009L 0.47H 0.3339L 0.3203H 0.3322L 0.2678H 0.3529L 0.2133H 0.3872L 0.2214H |Air, where Air is air, H is TiO2, L is SiO2, the incident angle is 45°, and the design wavelength is 1200nm;

[0029] like Figure 2 and Figure 3 As shown, this invention exhibits a reflectance >92% in the 450-800nm ​​spectral range and a transmittance >92% in the 1700-3400nm spectral range.

[0030] like Figure 4 , Figure 5 and Figure 6 As shown, in the adhesive application process of the present invention, special tooling is required. The adhesive application tooling consists of a tooling base, a silicone pad, and a frame from bottom to top. The three parts are combined to form a concave surface with a height difference of less than 50μm, which is the adhesive application area. The tooling base includes a bottom surface 1, a first screw hole 2, and a protruding structure 3. The silicone pad includes a silicone square frame 4 and a second screw hole 5. The frame includes a stainless steel square frame 6 and a third screw hole 7. The tooling base, silicone pad, and frame are fixed together by the first screw hole 2, the second screw hole 5, and the third screw hole 7 to form the adhesive application area.

[0031] like Figure 7 As shown, the photoresist coating process of this utility model is divided into two steps: coating and spin coating. After coating, the photoresist is fully baked at a temperature of >100℃ for a duration of >10 hours. The spin coating speed is 1000 r / min for 90 seconds. After spin coating, the photoresist is baked at a temperature of >100℃ for >180 seconds. After cooling, the coated tooling is obtained.

[0032] like Figure 7 As shown, the coating process of this utility model adopts the magnetron sputtering method, and TiO2 and SiO2 are deposited sequentially according to the film system design parameters. The power is controlled at 300W when depositing TiO2 film and 200W when depositing SiO2 film. The vacuum degree is less than 4.0×10^-4Pa, the working pressure is 0.7Pa, and the temperature is 20℃.

[0033] like Figure 7 As shown, the peeling process of this utility model is as follows: the tooling obtained after coating is immersed in the adhesive remover solution for 48 hours. During the peeling process after immersion, the adhesive layer and the film layer are completely separated using a peeling tool to obtain a formal sample of the ultrathin dichroic mirror, and subsequent related tests are performed.

[0034] Finally, it should be noted that the above embodiments are only used to illustrate this utility model patent and are not intended to limit the technical solutions described in this utility model patent. Therefore, although this specification has described this utility model in detail with reference to the above embodiments, those skilled in the art should understand that modifications can still be made to this utility model; and all technical solutions and improvements that do not depart from the scope of this utility model should be covered within the scope of the claims of this utility model.

Claims

1. An ultrathin dichroic mirror, characterized in that, The dichroic mirror is a thin film with a thickness of 3.1-3.2 μm. The thin film is composed of alternating layers of titanium dioxide and silicon dioxide. The bottom layer of the thin film is a silicon dioxide layer. The light-transmitting aperture area of ​​the ultrathin dichroic mirror has no substrate.

2. The ultrathin dichroic mirror according to claim 1, characterized in that, The titanium dioxide layer and silicon dioxide layer together comprise 37 layers.

3. The ultrathin dichroic mirror according to claim 1, characterized in that, The basic film system of the thin film is |(0.5HL 0.5H)^6 (0.4H 0.8L 0.4H)^5 (0.3H 0.6L 0.3H)^5|Air, where Air is air, H is TiO2, L is SiO2, and the designed wavelength is 1200nm.

4. The ultrathin dichroic mirror according to claim 3, characterized in that, The final membrane structure is as follows: | 0.1487H 0.1191L 0.1952H 0.8586L 0.6725H 0.8193L 0.7918H 0.7957L 0.7386H 0.7255L 0.6954H 0.7086L 0.6778H 0.6786L 0.5569H 0.4965L 0.4973H 0.5962L 0.6065H 0.5852L 0.5058H 0.4796L 0.4553H 0.4256L 0.479H 0.3821L 0.4024H 0.4009L 0.47H 0.3339L 0.3203H 0.3322L 0.2678H 0.3529L 0.2133H 0.3872L 0.2214H|Air.

5. The ultrathin dichroic mirror according to claim 1, characterized in that, In the spectral range of 450-800nm, the reflectance is >92%, and in the spectral range of 1700-3400nm, the transmittance is >92%.

6. The ultrathin dichroic mirror according to claim 1, characterized in that, The working angle of the ultrathin dichroic mirror is 45°.

7. The ultrathin dichroic mirror according to claim 1, characterized in that, The ultrathin dichroic mirror measures 32mm × 32mm.

8. The ultrathin dichroic mirror according to claim 1, characterized in that, Under its own weight, when the temperature range is 243.15K - 328.15K, the maximum stress is < 10^6 Pa and the maximum deformation is < 10^-3 μm.

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