Multi-channel partitioned coated optical filter and preparation method thereof

Abstract

The invention relates to a coated optical filter, in particular to a multi-channel partitioned coated optical filter and a preparation method thereof, and solves the problems of spectrum crosstalk and aliasing among a plurality of slits when an existing multi-slit imaging spectrometer is actually used. The device comprises a multi-slit surface and a coated light filter which are sequentially arranged from top to bottom, the coated light filter comprises a front surface film layer, a glass substrate and a rear surface film layer which are sequentially arranged from top to bottom, two or more light filtering areas are arranged on the multi-slit surface side by side, a slit is formed in each light filtering area, all the slits are parallel to one another, and the number of the slits is larger than or equal to one. Different filtering areas correspond to working wave band requirements of different channels, meanwhile, optical thickness limitation of front surface film layers and rear surface film layers of the different filtering areas is given to control working wave band ranges of the different channels, spectrum crosstalk and aliasing are avoided, and meanwhile imaging quality is guaranteed.

Description

Technical Field

[0001] This invention relates to coated filters, specifically to a multi-channel partitioned coated filter and its preparation method. Background Technology

[0002] In the field of Earth observation, imaging spectrometers are widely used as common observation tools in various observation missions. With technological advancements and the increasing complexity of observation tasks, imaging spectrometers often need to meet the requirements of wide spectral density and high signal-to-noise ratio (SNR). To improve the SNR, imaging spectrometers typically rely on methods such as oscillation scanning and increasing the numerical aperture. However, increasing the SNR through oscillation scanning can affect the platform stability of the imaging spectrometer, while increasing the numerical aperture leads to a larger overall aperture of the optical system, which increases the manufacturing difficulty of large-aperture optical systems. With technological advancements, multi-slit imaging spectrometers are gradually being adopted in Earth observation. Their structure typically involves placing a multi-slit coated filter at the front mirror plane of the imaging spectrometer. This structure can obtain multi-channel information in a single exposure, effectively improving the SNR. However, in practical use, existing multi-slit imaging spectrometers suffer from spectral crosstalk and aliasing problems between the multiple slits. Summary of the Invention

[0003] The purpose of this invention is to solve the problem of spectral crosstalk and aliasing between multiple slits in existing multi-slit imaging spectrometers during practical use, and to provide a multi-channel partitioned coated filter and its preparation method.

[0004] To achieve the above-mentioned objectives, the present invention provides the following technical solution: A multi-channel partitioned coated filter is characterized in that it includes multiple slit surfaces and a coated filter arranged sequentially from top to bottom, wherein the coated filter includes a front surface film layer, a glass substrate and a rear surface film layer arranged sequentially from top to bottom. The multi-slit surface is arranged side by side with Each filter area Each filter area has a slit, and all slits are parallel to each other; No. The front surface film layer corresponding to the slits in each filter region includes a front surface dielectric film, and the total thickness of the front surface film layer is... The total refractive index is ; satisfy: ; in: The refractive indices are, in order, the first front surface dielectric film to the a-th front surface dielectric film. — The thicknesses are, in order, the thicknesses of the first front surface dielectric film to the a-th front surface dielectric film; No. The back surface film corresponding to the slits within each filter region includes a b-layer back surface dielectric film, and the total thickness of the back surface film is... ′, total refractive index ′; 'satisfy: ; in: The refractive indices are, in order, from the first back surface dielectric layer to the b-th back surface dielectric layer. — The thicknesses are, in order, from the first rear surface dielectric film to the b-th rear surface dielectric film; Two adjacent filter regions satisfy: ; in: For the first The total thickness of the front surface film in each filtering region For the first The total refractive index of the front surface film in each filter region For the first The total thickness of the rear surface film in each filter region For the first The total refractive index of the back surface film in each filter region is the refractive index of air.

[0005] Furthermore, the multi-slit surface is bonded to the coated filter using an adhesive bonding process. The total thickness of the front surface film layer within each filtering area Total thickness of the back surface film 'equal.

[0006] Furthermore, two adjacent filter regions satisfy the following: .

[0007] Furthermore, the front surface dielectric film of the front surface film layer is made of tantalum oxide and silicon dioxide, and from the first front surface dielectric film to the a-th front surface dielectric film, the front surface dielectric film made of tantalum oxide and the front surface dielectric film made of silicon dioxide are alternately arranged. The material of the rear surface dielectric film of the rear surface film layer is tantalum oxide and silicon dioxide, and from the first rear surface dielectric film to the b-th rear surface dielectric film, the rear surface dielectric film made of tantalum oxide and the rear surface dielectric film made of silicon dioxide are alternately arranged.

[0008] Meanwhile, the present invention also provides a method for preparing the above-mentioned multi-channel partitioned coated filter, which is characterized by: S1. Prepare a multi-slit surface and a glass substrate, and arrange them side by side on the multi-slit surface. Each filter area A slit is made in each filter area, and all the slits are parallel to each other, with the glass substrate placed below the multi-slit surface; S2. A front surface film layer is deposited on the upper surface of the glass substrate at the slit positions corresponding to each filtering area. The front surface film layer corresponding to the slits in each filter region includes a front surface dielectric film, and the total thickness of the front surface film layer is... The total refractive index is ; satisfy: ; in: The refractive indices are, in order, the first front surface dielectric film to the a-th front surface dielectric film. — The thicknesses are, in order, the thicknesses of the first front surface dielectric film to the a-th front surface dielectric film; A back surface film is deposited on the lower surface of the glass substrate at the slit positions corresponding to each filtering area. The back surface film corresponding to the slits within each filter region includes a b-layer back surface dielectric film, and the total thickness of the back surface film is... ′, total refractive index ′; 'satisfy: ; in: The refractive indices are, in order, from the first back surface dielectric layer to the b-th back surface dielectric layer. — The thicknesses are, in order, from the first rear surface dielectric film to the b-th rear surface dielectric film; And two adjacent filter regions satisfy: ; in: For the first The total thickness of the front surface film in each filtering region For the first The total refractive index of the front surface film in each filter region For the first The total thickness of the rear surface film in each filter region For the first The total refractive index of the rear surface film in each filter region; The front surface film layer, the glass substrate, and the rear surface film layer constitute a coated filter. S3. Combine the multi-slit surface with the coated filter to complete the preparation of the multi-channel zoned coated filter.

[0009] Furthermore, in step S3, the multi-slit surface and the coated filter are bonded together using an adhesive bonding process.

[0010] Furthermore, in step S2, two adjacent filter regions satisfy the following: ; And the The total thickness of the front surface film layer within each filtering area Total thickness of the back surface film 'equal.

[0011] Compared with the prior art, the beneficial effects of the present invention are: (1) The present invention provides a multi-channel partitioned coated filter with different filtering regions to correspond to the working band requirements of different channels. At the same time, it provides optical thickness limits for the front and rear surface films of different filtering regions to control the working band range of different channels, avoid spectral crosstalk and aliasing, and ensure imaging quality.

[0012] (2) In the multi-channel partitioned coated filter provided by the present invention, the multiple slit surfaces are bonded to the coated filter using an adhesive bonding process, and the first... The total thickness of the front surface film layer within each filtering area Total thickness of the back surface film The parallelism between the slit and the coated filter is equal, thus avoiding the introduction of parallelism differences. Attached Figure Description

[0013] Figure 1 This is a schematic diagram of the structure of an embodiment of a multi-channel partitioned coated filter according to the present invention.

[0014] The annotations in the attached figures are explained as follows: 1-Multiple slit surfaces, 11-Slits; 2-Coated filter, 21-Front surface film, 22-Glass substrate, 23-Rear surface film. Detailed Implementation

[0015] The present invention will be further described below with reference to the accompanying drawings and exemplary embodiments.

[0016] Reference Figure 1The present invention provides a multi-channel partitioned coated filter comprising a multi-slit surface 1 and a coated filter 2 arranged sequentially from top to bottom. The coated filter 2 comprises a front surface film layer 21, a glass substrate 22 and a rear surface film layer 23 arranged sequentially from top to bottom, and the coated filter 2 and the multi-slit surface 1 are bonded together by an adhesive bonding process.

[0017] A series of slits are arranged side by side on the multi-slit surface 1. Each filter area Each filter region has a slit 11, and all slits 11 are parallel to each other. In this way, the slit 11 in each filter region is equivalent to a channel, thereby realizing multi-channel partitioning.

[0018] exist The first filter region The front surface film layer 21 corresponding to the slit 11 within each filter region includes a front surface dielectric film layer a. The front surface dielectric film layer 21 is made of tantalum oxide and silicon dioxide, and from the first front surface dielectric film layer to the a-th front surface dielectric film layer, the tantalum oxide front surface dielectric film and the silicon dioxide front surface dielectric film are alternately arranged. The total thickness of the front surface film layer 21 is [missing information]. The total refractive index is Total refractive index That is, the equivalent refractive index of the entire front surface film 21 is calculated by dividing the total optical path by the total geometric thickness. satisfy: ; in: The refractive indices are, in order, the first front surface dielectric film to the a-th front surface dielectric film. — The thicknesses are, in order, the thicknesses of the first front surface dielectric film to the a-th front surface dielectric film; No. The back surface film layer 23 corresponding to the slit 11 within each filter region includes a b-layer back surface dielectric film. The back surface dielectric film of the back surface film layer 23 is made of tantalum oxide and silicon dioxide, and from the first back surface dielectric film to the b-th back surface dielectric film, the tantalum oxide back surface dielectric film and the silicon dioxide back surface dielectric film are alternately arranged. The total thickness of the back surface film layer 23 is [missing information]. ′, total refractive index ′; 'satisfy: ; in: The refractive indices are, in order, from the first back surface dielectric layer to the b-th back surface dielectric layer. — The thicknesses are, in order, from the first rear surface dielectric film to the b-th rear surface dielectric film; And two adjacent filter regions satisfy: ; in: For the first The total thickness of the front surface film 21 in each filter region For the first The total refractive index of the front surface film 21 in each filter region For the first The total thickness of the rear surface film 23 in each filter region For the first The total refractive index of the rear surface film 23 in each filter region is the refractive index of air.

[0019] In this embodiment, two adjacent filter regions satisfy the following: ; Because in this embodiment, the multi-slit surface 1 and the coated filter 2 are bonded together using an adhesive bonding process, therefore the first The total thickness of the front surface film 21 within each filter area Total thickness of the rear surface film 23 Equality can avoid introducing parallelism between slit 11 and coated filter 2.

[0020] Meanwhile, the present invention also provides a method for preparing the above-mentioned multi-channel partitioned coated filter, comprising the following steps: S1. Prepare the multi-slit surface 1 and the glass substrate 22, and arrange them side by side on the multi-slit surface 1. Each filter area A slit 11 is opened in each filter area, and all slits 11 are parallel to each other, and the glass substrate 22 is placed below the multi-slit surface 1. S2. A front surface film layer 21 is deposited on the upper surface of the glass substrate 22 at the position of the slit 11 corresponding to each filtering area. The front surface film layer 21 corresponding to the slit 11 in each filter area includes a front surface dielectric film, and the total thickness of the front surface film layer 21 is [missing information]. The total refractive index is ; satisfy: ; in: The refractive indices are, in order, the first front surface dielectric film to the a-th front surface dielectric film. — The thicknesses are, in order, the thicknesses of the first front surface dielectric film to the a-th front surface dielectric film; A back surface film 23 is deposited on the lower surface of the glass substrate 22 at the slit 11 positions corresponding to each filtering area. The back surface film 23 corresponding to the slit 11 within each filter region includes a b-layer back surface dielectric film, and the total thickness of the back surface film 23 is [missing information]. ′, total refractive index ′; 'satisfy: ; in: The refractive indices are, in order, from the first back surface dielectric layer to the b-th back surface dielectric layer. — The thicknesses are, in order, from the first rear surface dielectric film to the b-th rear surface dielectric film; And two adjacent filter regions satisfy: ; in: For the first The total thickness of the front surface film 21 in each filter region For the first The total refractive index of the front surface film 21 in each filter region For the first The total thickness of the rear surface film 23 in each filter region For the first The total refractive index of the rear surface film 23 in each filter region; The front surface film layer 21, the glass substrate 22, and the rear surface film layer 23 constitute the coated filter 2; In this embodiment, two adjacent filter regions satisfy the following: ; And the The total thickness of the front surface film 21 within each filter area Total thickness of the rear surface film 23 'equal; S3. The multi-slit surface 1 and the coated filter 2 are bonded together using an adhesive bonding process to complete the preparation of the multi-channel partitioned coated filter.

[0021] This invention provides a boundary condition constraint for a coated filter from the perspective of optical path difference. Essentially, it belongs to the aberration balance control of an optical system. The overall manufacturing process is simple and easy to understand.

[0022] During operation, incident light is directed at slits 11 in different filtering regions of the multi-slit surface 1. After passing through the front surface film 21, glass substrate 22 and rear surface film 23 in each filtering region, outgoing light of different wavelengths is formed.

[0023] The embodiments described above are merely illustrative of specific implementations of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made to the technical solutions of the present invention by those skilled in the art without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A multi-channel zoned coated filter, characterized in that: It includes a multi-slit surface (1) and a coated filter (2) arranged sequentially from top to bottom. The coated filter (2) includes a front surface film layer (21), a glass substrate (22) and a rear surface film layer (23) arranged sequentially from top to bottom. The multi-slit surface (1) is provided with side by side with Each filter area Each filter area has a slit (11) and all slits (11) are parallel to each other; No. The front surface film (21) corresponding to the slit (11) in each filter area includes a front surface dielectric film, and the total thickness of the front surface film (21) is The total refractive index is ; satisfy: ； in: The refractive indices are, in order, the first front surface dielectric film to the a-th front surface dielectric film. — The thicknesses are, in order, the thicknesses of the first front surface dielectric film to the a-th front surface dielectric film; No. The back surface film (23) corresponding to the slit (11) in each filter region includes a b-layer back surface dielectric film, and the total thickness of the back surface film (23) is ′, total refractive index ′; 'satisfy: ； in: The refractive indices are, in order, from the first back surface dielectric layer to the b-th back surface dielectric layer. — The thicknesses are, in order, from the first rear surface dielectric film to the b-th rear surface dielectric film; Two adjacent filter regions satisfy: ； in: For the first The total thickness of the front surface film (21) in each filter region, For the first The total refractive index of the front surface film (21) in each filter region, For the first The total thickness of the rear surface film (23) in each filter region, For the first The total refractive index of the back surface film (23) in each filter region, is the refractive index of air.

2. The multi-channel partitioned coated filter according to claim 1, characterized in that: The multi-slit surface (1) and the coated filter (2) are bonded together using an adhesive bonding process. The total thickness of the front surface film (21) within each filter area Total thickness of the back surface film (23) 'equal.

3. The multi-channel partitioned coated filter according to claim 2, characterized in that: Two adjacent filter regions satisfy: 。 4. The multi-channel partitioned coated filter according to claim 1, characterized in that: The front surface dielectric film of the front surface film layer (21) is made of tantalum oxide and silicon dioxide, and from the first front surface dielectric film to the a-th front surface dielectric film, the front surface dielectric film made of tantalum oxide and the front surface dielectric film made of silicon dioxide are alternately arranged. The material of the rear surface dielectric film of the rear surface film layer (23) is tantalum oxide and silicon dioxide, and from the first rear surface dielectric film to the b-th rear surface dielectric film, the rear surface dielectric film made of tantalum oxide and the rear surface dielectric film made of silicon dioxide are alternately arranged.

5. A method for preparing a multi-channel partitioned coated filter as described in any one of claims 1-4, characterized in that: S1. Prepare a multi-slit surface (1) and a glass substrate (22), and arrange them side by side on the multi-slit surface (1). Each filter area A slit (11) is opened in each filter area, and all slits (11) are parallel to each other, and the glass substrate (22) is placed below the multi-slit surface (1); S2. A front surface film (21) is deposited on the upper surface of the glass substrate (22) at the position of the slit (11) corresponding to each filter area. The front surface film (21) corresponding to the slit (11) in each filter area includes a front surface dielectric film, and the total thickness of the front surface film (21) is The total refractive index is ; satisfy: ； in: The refractive indices are, in order, the first front surface dielectric film to the a-th front surface dielectric film. — The thicknesses are, in order, the thicknesses of the first front surface dielectric film to the a-th front surface dielectric film; A back surface film (23) is deposited on the lower surface of the glass substrate (22) at the position of the slit (11) corresponding to each filter area. The back surface film (23) corresponding to the slit (11) in each filter region includes a b-layer back surface dielectric film, and the total thickness of the back surface film (23) is ′, total refractive index ′; 'satisfy: ； in: The refractive indices are, in order, from the first back surface dielectric layer to the b-th back surface dielectric layer. — The thicknesses are, in order, from the first rear surface dielectric film to the b-th rear surface dielectric film; And two adjacent filter regions satisfy: ； in: For the first The total thickness of the front surface film (21) in each filter region, For the first The total refractive index of the front surface film (21) in each filter region, For the first The total thickness of the rear surface film (23) in each filter region, For the first The total refractive index of the back surface film (23) in each filter region, The refractive index of air; The front surface film layer (21), the glass substrate (22), and the rear surface film layer (23) constitute a coated filter (2). S3. Combine the multi-slit surface (1) with the coated filter (2) to complete the preparation of the multi-channel partitioned coated filter.

6. The method for preparing a multi-channel partitioned coated filter according to claim 5, characterized in that: In step S3, the multi-slit surface (1) and the coated filter (2) are bonded together using an adhesive bonding process.

7. The method for preparing a multi-channel partitioned coated filter according to claim 6, characterized in that: In step S2, two adjacent filter regions satisfy the following: ； And the first The total thickness of the front surface film (21) within each filter area Total thickness of the back surface film (23) 'equal.

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