Spliced mirror surface correction method based on spectral dispersion fringes

Abstract

The invention relates to the technical field of spliced telescopes, in particular to a spliced mirror surface correction method based on spectral dispersion fringes, which comprises the following steps of: filtering one or more specific wavebands of incident light through a band-stop filter, so that a known position spectral band gap appears on the spectrum of the incident light; incident light is utilized to irradiate splicing seams or splicing seam intersection points on the spliced mirror surface, and a dispersion prism is arranged on a reflected light path to perform dispersion on reflected light; interference is carried out on the dispersion light, interference fringes with different wavelengths are expanded in the direction perpendicular to dispersion, and two-dimensional interference fringes of a plurality of sub-mirrors are obtained; the spectral band gaps on the two-dimensional interference fringes of each sub-mirror are aligned by adjusting the poses of the plurality of sub-mirrors, so that the pose correction of the sub-mirror adjacent to the splicing seam or the splicing seam intersection point is completed; and each splicing seam or splicing seam intersection point on the spliced mirror surface is irradiated in sequence, so that the pose correction of all the sub-mirrors can be completed.

Description

Technical Field

[0001] This invention belongs to the field of spliced ​​telescope technology, and particularly relates to a spliced ​​mirror correction method based on spectral dispersion fringes. Background Technology

[0002] To achieve higher light-gathering capabilities and resolution, large-aperture astronomical telescopes often employ multiple sub-mirrors pieced together to form the primary mirror. However, minute tilt (i.e., confocal error) and axial translation error (i.e., phase error) exist between the various sub-mirrors, causing inconsistencies in the focal point and phase of the reflected light from each sub-mirror, severely impacting the system's imaging quality and resolution.

[0003] Traditional methods for detecting and correcting aberrations in mosaic telescopes (such as Shaker-Hartmann wavefront sensing and phase restoration) are insufficient for detecting the consistency of spectral channels when dealing with multi-channel, broadband, and complex mosaic structures. Because mosaic errors in individual sub-mirrors can cause misalignment of their dispersive spectra, the entire mosaic mirror surface becomes spectrally blurred, making it impossible to obtain a clear spectral line. Therefore, traditional solutions typically operate only at a single wavelength or narrow band. However, this correction method struggles to assess and correct aberration differences between different spectral channels, which is detrimental to broadband imaging or spectral detection. Summary of the Invention

[0004] In view of this, the present invention aims to provide a splicing mirror correction method based on spectral dispersion fringes, which realizes splicing mirror correction through dispersion fringes and facilitates the alignment of dispersion fringes by creating spectral gaps, thus overcoming the limitations of traditional calibration methods that can only be evaluated and corrected at a single wavelength.

[0005] To achieve the above objectives, the technical solution created by this invention is implemented as follows: This invention provides a method for correcting spliced ​​mirror surfaces based on spectral dispersion fringes, comprising: An incident light is provided by a light source, and one or more specific wavelengths of the incident light are filtered out by a band-stop filter, so that a spectral gap with a known position appears in the spectrum of the incident light. By illuminating the splicing seam or the intersection of splicing seams on the splicing mirror surface with incident light containing spectral gaps, and setting a dispersive prism in the reflected light path, the reflected light reflected by the sub-mirrors adjacent to the splicing seam or the intersection of splicing seams is dispersed to obtain the dispersed light of multiple sub-mirrors adjacent to the splicing seam or the intersection of splicing seams. Interference is performed on the dispersed light of multiple sub-mirrors adjacent to the splicing seam or the intersection of the splicing seam, and the interference fringes of different wavelengths are spread out in the direction perpendicular to the dispersion to obtain two-dimensional interference fringes of multiple sub-mirrors. Each sub-mirror has spectral gaps in the same band on its two-dimensional interference fringes of different bands. By adjusting the pose of multiple sub-mirrors, the spectral gaps on the two-dimensional interference fringes of different bands of each sub-mirror are aligned, thus completing the pose correction of the sub-mirrors adjacent to the splicing seam or the intersection of the splicing seam. By sequentially illuminating each seam or intersection of seams on the spliced ​​mirror surface, the pose correction of all sub-mirrors can be completed.

[0006] Preferably, an active adjuster is also provided in the reflected light path. The active adjuster is used to introduce a known tilt error so that the two-dimensional interference fringes obtained by detection are tilted.

[0007] Preferably, it further includes: setting a stepped lens in the reflected light path, introducing a known optical path change by translating the stepped lens, collecting dispersion fringes under different optical path states, and performing absolute optical path calibration on the spliced ​​mirror surface.

[0008] Preferably, the bandstop filter employs a switchable filter wheel, a wavelength-tunable bandstop filter, or a bandstop filter sheet.

[0009] Preferably, the dispersive light from multiple sub-mirrors adjacent to the seam or the intersection of the seam is input into the interferometer for interference.

[0010] Preferably, the dispersive prism is a triangular prism.

[0011] Preferably, two-dimensional interference fringes are collected by setting up a detector.

[0012] Compared with the prior art, the present invention can achieve the following beneficial effects: This invention corrects each spectral band of the incident light by first dispersing and then interfering, overcoming the drawback of traditional methods that only correct in a single band. Furthermore, it creates spectral band gaps in the spectrum using a bandstop filter, which serve as alignment criteria in the direction of spectral continuity. By using these spectral gaps as markers to align the dispersive interference fringes, it solves the problem of difficulty in aligning two-dimensional interference fringes in the direction of spectral continuity. The pose adjustment of the sub-mirrors is then performed with the alignment of the spectral dispersive fringes as the target, thereby achieving sub-mirror splicing error correction.

[0013] This invention utilizes the sensitivity of interference to phase misalignment to achieve subpixel-level stripe alignment detection, and by actively introducing known tilt errors, facilitates the alignment of spectral gaps. Attached Figure Description

[0014] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments and descriptions of the invention are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings: Figure 1This is a flowchart of a splicing mirror correction method based on spectral dispersion fringes provided in an embodiment of the present invention; Figure 2 This is an optical path structure diagram of spliced ​​mirror correction based on spectral dispersion fringes provided according to an embodiment of the present invention; Figure 3 This is a schematic diagram illustrating how splicing errors of sub-mirrors can cause spectral blurring. Figure 4 A schematic diagram of non-slanted stripes; Figure 5 This is a schematic diagram of the slanted stripes.

[0015] The reference numerals in the figures include: Sub-mirror 1, splicing seam 2, splicing seam intersection 3, step lens 4, dispersive prism 5, interference assembly 6, two-dimensional interference fringes 7, spectral band notch 8. Detailed Implementation

[0016] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only for explaining the invention and do not constitute a limitation thereof. Similar elements in different embodiments are referred to by associated similar element reference numerals. In the following embodiments, many details are described to facilitate a better understanding of the invention. However, those skilled in the art will readily recognize that some features may be omitted in different situations, or may be replaced by other elements, materials, or methods. In some cases, some operations related to the invention are not shown or described in the specification. This is to avoid obscuring the core parts of the invention with excessive description. For those skilled in the art, detailed description of these related operations is not necessary; the relevant operations can be fully understood based on the description in the specification and general technical knowledge in the art.

[0017] It should be noted that, unless otherwise specified, the embodiments and features described in this invention can be combined to form various implementations. Furthermore, the order of the steps or actions in the method description can be changed or adjusted in a manner readily apparent to those skilled in the art. Therefore, the various orders in the specification and drawings are merely for the clear description of a particular embodiment and do not imply a mandatory order, unless otherwise stated that a particular order must be followed.

[0018] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," and "counterclockwise," etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on this invention. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, features defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0019] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art will understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0020] The invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0021] Please see Figure 1 In one embodiment of the present invention, a method for splicing mirror correction based on spectral dispersion fringes is provided, comprising: S1: Use a light source to provide incident light, and use a band-stop filter to filter out one or more specific wavelengths of the incident light, so that a spectral gap with a known position appears in the spectrum of the incident light. S2: Illuminate the splicing seam or splicing seam intersection on the splicing mirror surface with incident light containing spectral gaps, and set a dispersive prism in the reflected light path to disperse the reflected light reflected by the sub-mirrors adjacent to the splicing seam or splicing seam intersection, thereby obtaining the dispersed light of multiple sub-mirrors adjacent to the splicing seam or splicing seam intersection. S3: Interference is performed on the scattered light of multiple sub-mirrors adjacent to the splicing seam or the intersection of the splicing seam, and the interference fringes of different wavelengths are spread out in the direction perpendicular to the dispersion to obtain two-dimensional interference fringes of multiple sub-mirrors. S4: There are spectral gaps of the same band on the two-dimensional interference fringes of different bands of each sub-mirror. By adjusting the pose of multiple sub-mirrors, the spectral gaps on the two-dimensional interference fringes of different bands of each sub-mirror are aligned, thus completing the pose correction of the sub-mirrors adjacent to the splicing seam or the intersection of the splicing seam. S5: Illuminate each seam or intersection of seams on the spliced ​​mirror surface in sequence to complete the pose correction of all sub-mirrors.

[0022] In step S1, incident light with a known spectral gap is first prepared. Specifically, a broadband light source is provided to emit broadband light as incident light. A band-stop filter is placed at the exit port of the broadband light source. The band-stop filter is used to filter out one or more specific wavelengths of the incident light to create a spectral gap at a known location in the incident light spectrum. Typically, a 10nm wide spectral band can be filtered out at 655nm to form a 10nm wide spectral gap. The band-stop filter can be a switchable filter wheel, a wavelength-tunable band-stop filter, or a band-stop filter sheet.

[0023] like Figure 2 As shown, in step S2, incident light with spectral gaps is used to illuminate the splicing mirror surface, which is typically the large-aperture primary mirror of the splicing telescope. The illumination position can be selected from the splicing seam 2 between adjacent sub-mirrors 1 on the splicing mirror surface, or the intersection point 3 of adjacent splicing seams. When the incident light illuminates the splicing seam 2, the two adjacent sub-mirrors 1 on both sides of the splicing seam 2 can reflect the incident light, and the reflected light includes the reflected light from the two adjacent sub-mirrors 1. When the incident light illuminates the splicing seam intersection point 3, multiple adjacent sub-mirrors 1 around the splicing seam intersection point 3 can reflect the incident light, and the reflected light includes the reflected light from the multiple adjacent sub-mirrors 1.

[0024] A dispersive prism 5 is placed in the transmission optical path of the reflected light from sub-mirror 1. The dispersive prism 5 is used to disperse the reflected light from different sub-mirrors 1 in space according to wavelength, thereby obtaining the dispersed light of multiple sub-mirrors 1 adjacent to the splicing seam 2 or the intersection point 3 of the splicing seam. The dispersive prism 5 can generally be a triangular prism.

[0025] In step S3, after the reflected light undergoes dispersion, an interference component 6 is placed along its transmission optical path. This component interferes with the dispersed light from multiple sub-mirrors 1. Specifically, the interference component 6 can be an interference grating or directly fed into a spectrometer, causing interference of light of the same wavelength band in the dispersed light. This results in interference fringes of different wavelengths spreading in a direction perpendicular to dispersion, forming two-dimensional interference fringes 7. A detector is placed at the rear end of the interference component 6 to collect the two-dimensional interference fringes 7. The direction of the interference fringes is perpendicular to the dispersion direction. One dimension of the two-dimensional interference fringes 7 represents the wavelength, and the other dimension represents the spatial distribution of interference fringes at each wavelength. Because interference fringes are highly sensitive to phase difference, any slight tilt or forward / backward deviation of the sub-mirrors 1 will affect their phase difference. Therefore, different wavelength bands of the reflected light from different sub-mirrors 1 will be offset and disordered, resulting in the obtained two-dimensional interference fringes 7 appearing blurred. Figure 3 This refers to the interference fringes in the traditional ambiguous state without spectral gap 8.

[0026] In step S4, since each sub-mirror 1 in this embodiment has spectral gaps 8 of the same wavelength band on its two-dimensional interference fringes 7, the sub-mirror 1 can be corrected based on the two-dimensional interference fringes 7. The correction process includes two parts: one part is to adjust the pose of the sub-mirror 1 to align the different wavelength band components in the two-dimensional interference fringes 7 in the lateral direction (i.e., perpendicular to the direction of dispersion); the other part is to adjust the pose of the sub-mirror 1 to align the different wavelength band components in the two-dimensional interference fringes 7 in the longitudinal direction (i.e., along the direction of dispersion). Lateral alignment can be determined by observing the two-dimensional interference fringes 7, but to further improve the lateral alignment accuracy, an active adjuster can be further set in the optical path of the reflected light. The active adjuster introduces a known tilt error, causing the bright and dark fringes of the two-dimensional interference fringes 7 to appear tilted. Compared to... Figure 4 The longitudinal fringes shown, and the tilted arrangement of the bright and dark fringes of the two-dimensional interference fringe 7 facilitate observation of the lateral alignment. Longitudinal alignment is more difficult, as the dispersive spectrum is hard to distinguish along its continuous direction. Therefore, during the adjustment of sub-mirror 1, it is difficult to determine whether the two-dimensional interference fringe 7 is aligned longitudinally, and it is also difficult to determine how to adjust sub-mirror 1 to align the two-dimensional interference fringe 7 longitudinally. Therefore, as... Figure 5 As shown, the incident light in this invention is provided with a spectral notch 8. Therefore, the spectral notch 8 can be used as the alignment basis. By adjusting the pose of the sub-mirrors 1 adjacent to the splicing seam 2 or the splicing seam intersection 3, the spectral notches 8 on the two-dimensional interference fringes 7 of different bands of each sub-mirror 1 can be aligned, thus achieving longitudinal alignment and completing the pose correction of the sub-mirrors adjacent to the splicing seam 2 or the splicing seam intersection 3.

[0027] In step S5, steps S1 to S4 are repeated so that the incident light with the spectral gap 8 sequentially illuminates each seam 2 or seam intersection 3 on the spliced ​​mirror surface, thus correcting each sub-mirror 1. During subsequent correction processes, some of the adjacent sub-mirrors 1 at the illuminated seam 2 or seam intersection 3 have already been corrected. Further correction can then use the already corrected sub-mirrors 1 as a reference to correct the poses of the other uncorrected sub-mirrors 1. To improve correction accuracy, multiple iterations can be performed until the entire spliced ​​mirror surface approaches an ideal mirror surface, and each sub-mirror 1 is in an ideal pose.

[0028] In summary, the above description is merely a preferred embodiment of this specification and is not intended to limit the scope of protection of this specification. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this specification should be included within the scope of protection of this specification.

[0029] The systems, apparatuses, modules, or units described in one or more of the above embodiments may be implemented by a computer chip or entity, or by a product having a certain function. A typical implementation device is a computer. Specifically, a computer may be, for example, a personal computer, a laptop computer, a cellular phone, a camera phone, a smartphone, a personal digital assistant, a media player, a navigation device, an email device, a game console, a tablet computer, a wearable device, or any combination of these devices.

[0030] It should also be noted that the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0031] The various embodiments in this specification are described in a progressive manner. Similar or identical parts between embodiments can be referred to interchangeably. Each embodiment focuses on describing the differences from other embodiments. In particular, the system embodiments are basically similar to the method embodiments, so the description is relatively simple; relevant parts can be referred to the descriptions in the method embodiments.

Claims

1. A method for correcting spliced ​​mirror surfaces based on spectral dispersion fringes, characterized in that, include: An incident light is provided by a light source, and one or more specific wavelengths of the incident light are filtered out by a band-stop filter, so that a spectral gap with a known position appears in the spectrum of the incident light. By illuminating the splicing seam or the intersection of splicing seams on the splicing mirror surface with incident light containing spectral gaps, and setting a dispersive prism in the reflected light path, the reflected light reflected by the sub-mirrors adjacent to the splicing seam or the intersection of splicing seams is dispersed to obtain the dispersed light of multiple sub-mirrors adjacent to the splicing seam or the intersection of splicing seams. Interference is performed on the dispersed light of multiple sub-mirrors adjacent to the splicing seam or the intersection of the splicing seam, and the interference fringes of different wavelengths are spread out in the direction perpendicular to the dispersion to obtain two-dimensional interference fringes of multiple sub-mirrors. Each sub-mirror has spectral gaps in the same band on its two-dimensional interference fringes of different bands. By adjusting the pose of multiple sub-mirrors, the spectral gaps on the two-dimensional interference fringes of different bands of each sub-mirror are aligned, thus completing the pose correction of the sub-mirrors adjacent to the splicing seam or the intersection of the splicing seam. By sequentially illuminating each seam or intersection of seams on the spliced ​​mirror surface, the pose correction of all sub-mirrors can be completed.

2. The method for splicing mirror correction based on spectral dispersion fringes according to claim 1, characterized in that, An active adjuster is also provided in the reflected light path. The active adjuster is used to introduce a known tilt error so that the detected two-dimensional interference fringes are tilted.

3. The method for splicing mirror correction based on spectral dispersion fringes according to claim 1, characterized in that, Also includes: A stepped lens is set in the reflected light path, and a known optical path change is introduced by translating the stepped lens. Dispersion fringes under different optical path states are collected, and the absolute optical path of the spliced ​​mirror is calibrated.

4. The method for splicing mirror correction based on spectral dispersion fringes according to claim 1, characterized in that, The band-stop filter employs a switchable filter wheel, a wavelength-tunable band-stop filter, or a band-stop filter sheet.

5. The method for splicing mirror correction based on spectral dispersion fringes according to claim 1, characterized in that, The dispersive light from multiple sub-mirrors adjacent to the seam or the intersection of the seams is input into the interferometer for interference.

6. The method for splicing mirror correction based on spectral dispersion fringes according to claim 1, characterized in that, The dispersive prism is a triangular prism.

7. The method for splicing mirror correction based on spectral dispersion fringes according to claim 1, characterized in that, Two-dimensional interference fringes are collected by setting up a detector.

Images