WO2021082053A1

WO2021082053A1 - Optical filter

Info

Publication number: WO2021082053A1
Application number: PCT/CN2019/116567
Authority: WO
Inventors: 林育菁
Original assignee: 潍坊歌尔微电子有限公司
Priority date: 2019-10-31
Filing date: 2019-11-08
Publication date: 2021-05-06
Also published as: CN110794499A

Abstract

An optical filter, comprising a bearing element (102) having a penetrating cavity (104) which is formed inside the bearing element (102) and penetrates through the thickness direction of the bearing element (102); and an optical filter film (106) overlapped on the bearing element (102) and covering an opening of the penetrating cavity (104). Through holes (110) are distributed on the optical filter film (106) in periodic patterns, and the optical filter film (106) is made of metallic glass.

Description

Filter

Technical field

The present disclosure relates to an optical filter.

Background technique

The wire mesh filter is a filter made of a laminated layer of a wire mesh and a dielectric. As part of the optical path, they are used to filter incident light to allow the frequency of interest to pass, while reflecting light of other frequencies.

Wire mesh filters have many applications for far infrared (FIR) and sub-millimeter wave bands of the electromagnetic spectrum. Filters like this have been used in FIR and sub-millimeter astronomical instruments for more than 40 years. Among them, they have two main uses: when used as band-pass or low-pass filters, they are cooled and block excess thermal radiation. Outside the observation frequency band, thereby reducing the noise equivalent power of the cryobolometer (detector); when used as a band-pass filter, it can be used to define the observation frequency band of the detector. The wire mesh filter can also be designed to be used at an angle of 45° to split the input optical signal into several paths for observation, or used as a polarization half-wave plate.

The filter membrane of a wire mesh filter is often constructed in a multilayer structure. There are usually two methods for constructing the multilayer filter film of the wire mesh filter. The first is to suspend the separated layers in the support ring in the form of small gaps between the layers. The small gaps are filled with air or under vacuum. However, such filters are mechanically fragile. In order to compensate for the insufficient strength of the multilayer structure of the filter film, a wire mesh filter was developed in which a durable SiC or SiN film is coated with gold. However, such a wire mesh filter still has the problem that SiC and SiN are not easy to process.

Another method of constructing the multilayer filter film of the wire mesh filter is to stack a dielectric thin film between the wire mesh layers, and heat-press the entire stack together to make it into a whole. The hot-pressed filter is mechanically strong, but when its impedance is matched to the vacuum, it exhibits pass-band fringes in the underlying dielectric material due to Fabry-Perot interference. Such a wire mesh filter has the following problems: the consumption of optical materials is large, the cooling resistance is deteriorated, and the thickness of the filter film is increased.

Therefore, there is an urgent need for an optical filter with a high elastic limit and impact resistance.

Summary of the invention

An object of the present disclosure is to provide a new technical solution for the optical filter.

According to a first aspect of the present disclosure, there is provided an optical filter including:

The carrier has a through cavity formed in the carrier and penetrates through the thickness direction thereof; and

A filter film is stacked on the carrier and covers an opening of the through cavity, the filter film is made of metallic glass and the filter film is provided with through holes in a periodic pattern.

Optionally, the filter film is formed by extremely rapid cooling, physical vapor deposition (PVD), electroplating, pulsed laser deposition (PLD), solid state reaction, ion radiation, and mechanical alloying.

Optionally, the carrier is made of polymer material, metal, silicon or silicon dioxide.

Optionally, the thickness of the filter film is 5 nm to 5 μm.

Optionally, the thickness of the filter film is 20 nm to 1000 μm.

Optionally, the inner diameter of the through hole is 1 nm to 100 μm.

Optionally, the inner diameter of the through hole is 100 nm to 10 μm.

According to an embodiment of the present disclosure, by using metallic glass instead of a metal wire mesh as the filter film, an optical filter that can withstand vibration and low temperature is provided without reducing the performance of the filter. The filter can obtain the same band pass function as the metal mesh filter, ensuring the filtering performance.

Through the following detailed description of exemplary embodiments of the present invention with reference to the accompanying drawings, other features and advantages of the present invention will become clear.

Description of the drawings

The drawings incorporated in the specification and constituting a part of the specification illustrate the embodiments of the present invention, and together with the description are used to explain the principle of the present invention.

Fig. 1 schematically shows the structure of an embodiment of the optical filter of the present invention.

Detailed ways

Various exemplary embodiments of the present invention will now be described in detail with reference to the accompanying drawings. It should be noted that unless specifically stated otherwise, the relative arrangement of components and steps, numerical expressions and numerical values set forth in these embodiments do not limit the scope of the present invention.

The following description of at least one exemplary embodiment is actually only illustrative, and in no way serves as any limitation to the present invention and its application or use.

The technologies, methods, and equipment known to those of ordinary skill in the relevant fields may not be discussed in detail, but where appropriate, the technologies, methods, and equipment should be regarded as part of the specification.

In all examples shown and discussed herein, any specific value should be interpreted as merely exemplary, rather than as a limitation. Therefore, other examples of the exemplary embodiment may have different values.

It should be noted that similar reference numerals and letters indicate similar items in the following drawings, and therefore, once an item is defined in one drawing, it does not need to be further discussed in subsequent drawings.

The present disclosure provides an optical filter including a carrier and a filter film provided on the carrier.

Fig. 1 shows a schematic structural diagram of an embodiment of the optical filter of the present disclosure. Referring to FIG. 1, the carrier 102 has a through cavity 104 formed therein and penetrates in the thickness direction of the carrier 102, and a filter film 106 is connected to the carrier 102. The filter film 106 is made of metallic glass, specifically formed by processes such as extremely rapid cooling, physical vapor deposition (PVD), electroplating, pulsed laser deposition (PLD), solid-state reaction, ion radiation, and mechanical alloying. The filter film 106 has through holes 110 arranged in a periodic pattern. The shape of the through hole 110 may be selected from a circle, an ellipse, a square, a cross, and the like. In an embodiment, the through holes 110 may also be uniformly arranged. The thickness of the filter film 106 may be 5 nm to 5 μm, preferably 20 nm to 1000 μm. Since the filter film 106 is made of metallic glass, the resonance of incident light on the surface of the filter film and the surface plasmon realizes the selection of light of a specific wavelength.

The through cavity 104 has two opposite openings. The filter film 106 is stacked on the carrier 102 to cover one of the two openings of the through cavity 104, so that the incident light 108 can pass through the filter film 106 from one opening of the through cavity 104 and enter the through cavity 104, and from the other Opening out (not shown).

The carrier 102 may be made of polymer material, metal, silicon or silicon dioxide. The through cavity 104 can be formed by a process well known to those skilled in the art, for example, by etching, etc., and no detailed description of the process will be given here.

Since metallic glass is an amorphous material, it is isotropic and uniform. In addition, there are basically no defects caused by polycrystalline structures such as grain boundaries and segregation, and the size effect is small. Therefore, when designing the filter, it is not necessary to consider the changes in physical properties due to anisotropy and size, which is beneficial to the structural design of the filter. In addition, since metallic glass is an alloy composed of multiple elements, the range of material selection in filter design is widened, and higher performance filters can be designed and manufactured.

For example, metallic glass may contain a variety of transition metal elements, and may optionally contain one or more non-metal elements. The metallic glass containing transition metal elements can have Sc, Y, La, Al, Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Mn, Tc, Re, Fe, Ru, Os, Co, Rh At least one of, Ir, Ni, Pd, Pt, Cu, Ag, Au, Zn, Cd and Hg. Any suitable transition metal element or combination thereof can be suitably used. In addition, any suitable non-metal elements or combinations thereof can also be appropriately used. For example, non-metal elements can be F, Cl, Br, I, At, O, S, Se, Te, Po, N, P, As, Sb, Bi, C, Si, Ge, Sn, Pb and B any type.

Because metallic glass has irregular atomic arrangement and no specific slip surface, it has higher strength than crystalline metal and has excellent fatigue properties and elastic deformation capabilities. The modulus of elasticity of metallic glass is about one-third that of crystalline metal, but its tensile strength is three times that of it. For example, the strength of Mg alloy is 300MPa, the strength of Mg-based metallic glass is 800MPa, the strength of FeCoBSiNb metallic glass is 4400MPa, and the strength of SUS304 stainless steel is 1400MPa.

Therefore, the use of metallic glass as the filter film can provide a sufficient elastic limit without the need for a lower dielectric material layer, while ensuring the strength of the film layer. Since the lower dielectric material layer is eliminated, interference fringes will not appear.

The filter of the present disclosure uses metallic glass as the filter film, which can withstand low temperatures and withstand sudden pressure changes when returning from a vacuum state to a normal pressure state, so it is suitable for extreme environments such as those at an altitude of more than five kilometers. Observation instruments for highlands, Antarctic regions and even space environments.

Although some specific embodiments of the present invention have been described in detail through examples, those skilled in the art should understand that the above examples are only for illustration and not for limiting the scope of the present invention. Those skilled in the art should understand that the above embodiments can be modified without departing from the scope and spirit of the present invention. The scope of the invention is defined by the appended claims.

Claims

An optical filter, which includes:

The carrier has a through cavity formed in the carrier and penetrates through the thickness direction thereof; and

A filter film, stacked on the carrier and covering an opening of the through cavity;

The filter film is made of metallic glass, and through holes are arranged in a periodic pattern on the filter film.
The filter according to claim 1, wherein the filter film is formed by extremely rapid cooling, physical vapor deposition, electroplating, pulsed laser deposition, solid state reaction, ion radiation, and mechanical alloying. .
The optical filter according to claim 1, wherein the carrier is made of polymer material, metal, silicon or silicon dioxide.
The optical filter according to claim 1, wherein the thickness of the optical filter film is 5 nm to 5 μm.
The optical filter according to claim 1, wherein the thickness of the optical filter film is 20 nm to 1000 μm.
The optical filter according to claim 1, wherein the shape of the through hole is a circle, an ellipse, a square, or a cross.