CN110794499A

CN110794499A - Light filter

Info

Publication number: CN110794499A
Application number: CN201911054933.8A
Authority: CN
Inventors: 林育菁
Original assignee: Goertek Inc
Current assignee: Weifang Goertek Microelectronics Co Ltd
Priority date: 2019-10-31
Filing date: 2019-10-31
Publication date: 2020-02-14
Also published as: WO2021082053A1

Abstract

A first aspect of the present disclosure discloses an optical filter comprising: a carrier (102) having a through cavity (104) formed therein and extending through the thickness direction thereof; and a filter film (106) superimposed on the carrier (102) and covering one opening of the through cavity (104), through holes being arranged in a periodic pattern on the filter film, the filter film (106) being made of metallic glass.

Description

Light filter

Technical Field

The present disclosure relates to an optical filter.

Background

Wire mesh filters are filters made from a stack of wire mesh and dielectric. As part of the optical path, they are used to filter incident light to allow the frequencies of interest to pass through while reflecting light at other frequencies.

Wire mesh filters have many applications for the 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, where they have two main uses: when acting as a band pass or low pass filter, is cooled and blocks unwanted thermal radiation outside the observation band, thereby reducing the noise equivalent power of the bolometer (detector); when used as a bandpass filter, can be used to define the viewing band of the detector. Wire mesh filters can also be designed to be used at 45 ° angles to split the incoming optical signal into several paths for viewing, or to act as a polarizing half-wave plate.

The filter membranes of wire mesh filters are often constructed in a multilayer structure. There are generally two methods for constructing the multilayer filter of the wire mesh filter. The first is to suspend the separated layers in a support ring with a small gap between the layers, the gap being filled with air or under vacuum. However, such filters are mechanically fragile. To compensate for the insufficiently high strength of the multilayer structure of the filter membrane, a wire mesh filter has been developed in which a durable SiC or SiN film is coated with gold. However, such wire mesh filters still suffer from the problem that SiC and SiN are not easily processed.

Another method of constructing the multi-layer filter membrane of a wire mesh filter is to stack a dielectric film between layers of wire mesh and hot compress the entire stack together to make it integral. The hot pressed filter is mechanically robust but exhibits pass-band fringes in the underlying dielectric material due to fabry-perot interference when its impedance is matched to vacuum. Such wire mesh filters have the following problems: the consumption of optical materials is high, the cooling resistance is poor, and the thickness of the filter film is increased.

Therefore, there is a need for an optical filter that has a high elastic limit and is impact resistant.

Disclosure of Invention

It is an object of the present disclosure to provide a new solution for an optical filter.

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

a carrier having a through cavity formed therein and extending through the carrier in a thickness direction thereof; and

a filter film stacked on the carrier and covering one opening of the through cavity, the filter film being made of metallic glass and having through holes arranged in a periodic pattern thereon.

Alternatively, the filter film is formed by means of ultra-rapid cooling, Physical Vapor Deposition (PVD), electroplating, Pulsed Laser Deposition (PLD), solid-state reaction, ion irradiation, and mechanical alloying.

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

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

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

Optionally, the inner diameters of the through holes are all 1nm to 100 μm.

Optionally, the inner diameters of the through holes are all 100nm to 10 μm.

According to an embodiment of the present disclosure, an optical filter capable of withstanding shock and low temperature is provided without degrading the performance of the filter by using a metallic glass instead of a wire mesh as a filter film. The filter can obtain the same band-pass function as a wire mesh filter, and ensures the filtering performance.

Other features of the present invention and advantages thereof will become apparent from the following detailed description of exemplary embodiments thereof, which proceeds with reference to the accompanying drawings.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description, serve to explain the principles of the invention.

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

Detailed Description

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

The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way intended to limit the invention, its application, or uses.

Techniques, methods, and apparatus known to those of ordinary skill in the relevant art may not be discussed in detail but are intended to be part of the specification where appropriate.

In all examples shown and discussed herein, any particular value should be construed as merely illustrative, and not limiting. Thus, other examples of the exemplary embodiments may have different values.

It should be noted that: like reference numbers and letters refer to like items in the following figures, and thus, once an item is defined in one figure, further discussion thereof is not required in subsequent figures.

The present disclosure provides a filter including a carrier and a filter film disposed on the carrier.

FIG. 1 shows a schematic diagram of the structure of one embodiment of the optical filter of the present disclosure. Referring to fig. 1, carrier 102 has a through cavity 104 formed therein that penetrates in the thickness direction of carrier 102, and a filter film 106 is attached to carrier 102. The filter film 106 is made of metallic glass, and is specifically formed by processes such as extremely rapid cooling, Physical Vapor Deposition (PVD), electroplating, Pulsed Laser Deposition (PLD), solid state reaction, ion irradiation, and mechanical alloying. The through holes 110 are arranged in a periodic pattern on the filter film 106. The shape of the through-hole 110 may be selected from a circle, an ellipse, a square, a cross, and the like. In one embodiment, the through holes 110 may also be uniformly arranged. The thickness of the filter 106 may be 5nm to 5 μm, preferably 20nm to 1000 μm. Since the filter 106 is made of metallic glass, selection of light of a specific wavelength is achieved by resonance of incident light with surface plasmons on the surface of the filter.

The through cavity 104 has two opposite openings. The filter film 106 is superimposed on the carrier 102, covering one of the two openings of the through cavity 104, so that the incident light 108 can enter the through cavity 104 from one opening of the through cavity 104, through the filter film 106, and exit from the other opening (not shown).

The carrier 102 may be made of a polymer material, metal, silicon, or silicon dioxide. The through cavity 104 may be formed by processes known to those skilled in the art, such as by etching, etc., and will not be described in detail herein with respect to the processes.

Since metallic glass is an amorphous material, it is isotropic and uniform. In addition, defects caused by polycrystalline structures such as grain boundaries and segregation are substantially absent, and the size effect is small. Therefore, it is not necessary to consider the change in physical properties due to anisotropy and size when designing the optical filter, which is advantageous for the structural design of the optical filter. In addition, since the metallic glass is an alloy composed of a plurality of elements, the range of material selection in the filter design is widened, and a higher performance filter can be designed and manufactured.

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

Since the metallic glass has an irregular atomic arrangement and no specific slip plane, it has higher strength than crystalline metals and has excellent fatigue properties, elastic deformability. The elastic modulus of metallic glasses is about one third of that of crystalline metals, but the tensile strength is three times that of crystalline metals. 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 1400 MPa.

Therefore, by using the metal glass as the filter film, the sufficient elastic limit can be provided without a lower dielectric material layer, and the strength of the film layer is ensured. Interference fringes do not occur due to the elimination of the underlying dielectric material layer.

The optical filter of the present disclosure uses the metal glass as the optical filter film, can withstand low temperature, and can withstand sudden pressure change when returning from a vacuum state to a normal pressure state, and thus is suitable for observation instruments in extreme environments such as highland, antarctic regions and even space environments with an altitude of five kilometers or more.

Although some specific embodiments of the present invention have been described in detail by way of examples, it should be understood by those skilled in the art that the above examples are for illustrative purposes only and are not intended to limit the scope of the present invention. It will be appreciated by those skilled in the art that modifications may be made to the above embodiments without departing from the scope and spirit of the invention. The scope of the invention is defined by the appended claims.

Claims

1. An optical filter, comprising:

a filter film superposed on the carrier and covering one opening of the through cavity;

the filter film is made of metal glass, and through holes are arranged on the filter film in a periodic pattern.

2. The filter of claim 1, wherein the filter film is formed by very rapid cooling, physical vapor deposition, electroplating, pulsed laser deposition, solid state reaction, ion irradiation, and mechanical alloying.

3. The filter of claim 1, wherein the carrier is made of a polymeric material, metal, silicon, or silicon dioxide.

4. The filter of claim 1, wherein the thickness of the filter film is 5nm to 5 μm.

5. The filter of claim 1, wherein the thickness of the filter film is 20nm to 1000 μm.

6. The filter of claim 1, wherein the shape of the through-hole is circular, elliptical, square, or cross-shaped.