CN218974671U - Off-axis three-reflector optical system compensator - Google Patents
Off-axis three-reflector optical system compensator Download PDFInfo
- Publication number
- CN218974671U CN218974671U CN202222422741.1U CN202222422741U CN218974671U CN 218974671 U CN218974671 U CN 218974671U CN 202222422741 U CN202222422741 U CN 202222422741U CN 218974671 U CN218974671 U CN 218974671U
- Authority
- CN
- China
- Prior art keywords
- axis
- optical
- compensator
- reflector
- optical system
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Images
Landscapes
- Instruments For Measurement Of Length By Optical Means (AREA)
Abstract
The patent discloses an off-axis three-reflector optical system compensator which is characterized in that an optical flat plate with a certain thickness is inserted in front of an interferometer focus of an off-axis three-reflector auto-collimation interference light path to serve as the compensator and is used for compensating aberration of light path elements such as a window and an optical filter. Under the constraint of an off-axis three-reflection design light path, an auto-collimation interference light path model with a compensator is optimized by establishing a plurality of light path configurations, so that the optimal thickness of the optical flat plate is obtained. The materials of the optical plate compensator are selected and optically coated according to the operating band of the interferometer. The off-axis three-reflector optical system testing device is simple and clear, can greatly reduce deviation of off-axis three-reflector optical system testing, improves efficiency and accuracy of off-axis three-reflector auto-collimation interference testing, and is particularly suitable for the testing of off-axis three-reflector optical systems with flat plate elements such as window sheets and optical filter sheets on rear light paths of the off-axis three-reflector optical systems.
Description
Technical Field
This patent belongs to optical design or optical detection field, relates to a compensator for off-axis three-reflector optical system dress debugging test usefulness.
Background
As a total reflection optical system, the off-axis three-reflection optical system has the advantages of wide working wave band and no chromatic aberration, simultaneously avoids the defect of central light blocking, and can realize a clear aperture of 1-2 m magnitude. The three reflectors have enough design variables, can be designed in a lightweight way, and can realize a field angle of about 20 degrees on the premise of ensuring resolution and imaging quality, so that the three reflectors are widely applied.
For example, mars remote sensing satellites developed in China-Tiansu, the high-resolution remote sensing camera adopts an off-axis three-reflector optical system, the focal length is 4640mm, the clear aperture is 387mm, and the field angle is 2 degrees.
The off-axis three-reflector optical system is usually tested by auto-collimation interferometry, and the optical path for testing the off-axis three-reflector optical system is mainly composed of the off-axis three-reflector system, a plane reflector and an interferometer. In the auto-collimation interference light path, the focal point of the interferometer is positioned on the focal plane of the off-axis three-mirror system, the optical wave front emitted by the interferometer is converted into plane wave to be emitted through the off-axis three-mirror system, and the plane wave is collimated by the plane reflector to return and is converged at the focal point of the optical system after passing through the optical system again.
The wave aberration information of the off-axis three-reflector optical system to be detected is carried back to the interferometer by the detection wave front sent by the interferometer, and the system wave aberration of the corresponding field of view under the current state is detected by the interferometer. According to the result of auto-collimation interferometry, a misalignment solving model can be established by methods such as computer-aided adjustment and sensitivity analysis, and the mirror of the measured off-axis optical system is finely adjusted to obtain a preset light path state.
The large-view-field off-axis three-reflection optical system is used as a front optical system, and is connected with plane optical elements such as a window sheet, an optical filter, a color separation film and the like, so that the functions of high-resolution imaging or multi-channel or multi-spectrum imaging and the like can be realized. Although the optical plate is an afocal element and does not affect the optical power of the optical system, the parallel plate is not an ideal optical element and cannot image perfectly.
In particular, when the optical plate is located in the converging optical path, the effect on the overall aberration is more pronounced, especially for large relative aperture large field of view optical paths. The effect of the thickness of the parallel plates on the aberrations must therefore be taken into account during the off-axis three-mirror optical design stage. In the optical design stage, optical elements such as a window sheet, an optical filter, a color separation sheet, a beam splitter and the like of the optical path after the off-axis three-reflector system are considered to form a complete imaging optical path.
After the off-axis three-mirror optical system is processed, only three single mirrors and system optical paths are fully tested, and after the preset indexes are met, the next work can be carried out, and the complete machine integration and test of the photoelectric remote sensing system can be participated.
However, in the auto-collimation interferometry optical path of the off-axis three-reflection optical system, if the position and the posture of the three reflectors are not constrained, the integrated optical path of the three reflectors only faces the direction of minimizing wave aberration, is trapped in a local minimum, is difficult to meet the image quality requirement of the full view field, and deviates from the designed preset optical path state.
If the adjustment test of the off-axis three-reflector optical system does not consider the functions of the window, the optical filter and other optical plates of the rear light path, the wavefront design residual error of the optical system formed by the three reflectors becomes large. When the auto-collimation interference light path is used for adjusting, the residual aberration of the off-axis three-reflector system is mixed with the wavefront difference caused by the position error of the reflector, so that the difference and the separation are difficult, and great difficulty is brought to the adjustment of the optical system.
The off-axis three-reflection optical system of the visible light wave band, the window, the optical filter and the like of the rear light path can always penetrate through the working wave band of the interferometer, so that in the off-axis three-reflection auto-collimation test and the installation and adjustment light path of the visible light wave band, the same glass material and the same thickness of optical flat plate are adopted as a compensator, and the off-axis three-reflection auto-collimation installation and adjustment test light path can be naturally consistent with the state of the designed light path.
However, the off-axis three-reflection optical system operating in the short-wave near-infrared, medium-wave infrared and long-wave infrared bands usually adopts optical materials such as monocrystalline Silicon (Silicon), monocrystalline Germanium (Germanium), zinc Selenide (Zinc Selenide) and the like in the optical path, and most of the materials cannot penetrate the working band of the laser interferometer, and particularly, after the working band coating treatment, the working wavelength of the laser interferometer is more difficult to pass.
The refractive index of the infrared band optical material is large and cannot be ignored even with a small thickness, and the influence of these windows on aberration correction needs to be considered in the design process of the optical system. Therefore, when the off-axis three-reflector optical system of the middle-wavelength infrared band is assembled and tested, the influence of optical elements such as an infrared window, an optical filter and the like is considered, so that the state of an optical path close to or consistent with the actually required system can be obtained.
By means of the design of the compensator for aspheric surface detection and the concept of zero compensation inspection, the optical compensator is required to be designed for an off-axis three-reflector auto-collimation interference optical path especially for an off-axis three-reflector optical system with middle wave infrared or long wave infrared and an off-axis three-reflector optical system with a flat plate element such as a window plate and a color separation plate on a rear optical path.
In the auto-collimation interferometry optical path, an optical compensator is used for replacing an optical flat plate element of a rear optical path, and meanwhile, residual aberration of the off-axis three-reflector auto-collimation optical path is compensated, so that the problem of adjustment test of an optical system with a window filter and the like on the rear optical path is solved, and the off-axis three-reflector measurement and the state that the adjustment optical path is closest to the original system optical path are obtained.
Two existing research results are reported in the optical report of 2021, such as Li Zhaoyang, and an off-axis three-reflector optical system compensator structure is reported, and a group of lenses are additionally arranged on an off-axis three-reflector optical path to serve as a compensator for system adjustment test. However, in simulation analysis, the method has a certain defect in design, the constraint of the original light path state is not considered, and in the design process of the front off-axis three-mirror optical system compensator, the method is not related to the original system, and the consistent light path state is difficult to obtain.
The China academy of sciences (China) institute of optical and precision machinery and physics (CUMENTS) Li Ming adopts a calculation holographic compensator to compensate the intermediate real image plane of the Rug off-axis three-mirror optical system, and is used for adjusting the primary mirror and the secondary mirror of the off-axis three-mirror optical system. The CGH compensator has the advantages of higher design and manufacturing difficulty, higher processing precision requirement, simple design and simple realization.
Different from the methods reported in the prior art and the literature, the off-axis three-reflector optical system is designed to be used as a constraint, and the compensator of the off-axis three-reflector auto-collimation optical path is optimally designed, so that the aberration of the auto-collimation interference optical path is compensated, the optical element of the back optical path is replaced, the optimal compensator design can be obtained, and the auto-collimation adjustment test of the off-axis three-reflector optical system is performed according to the optimal compensator, so that the optical state is close to the design value.
Compared with the existing method, the compensator structure and the design method provided by the patent perform auto-collimation interference adjustment and test on the off-axis three-reflection optical system, minimize the influence on the state of the optical path and obtain the closest design value of the state of the optical path.
Disclosure of Invention
According to the application background of the off-axis three-reflector optical system adjustment test, the compensator structure of the off-axis three-reflector optical system adjustment test is provided.
The main content of this patent is: and adding an optical flat plate with a certain thickness to serve as a compensator for adjusting the off-axis three-reflection optical system after the off-axis three-reflection optical system auto-collimates the interferometer focus of the interferometry optical path.
Light rays emitted by the interferometer pass through the compensator 2 in a divergent manner through the focus 1, and sequentially pass through the three mirrors 3, the secondary mirror 4, the main mirror 5 and the incident auto-collimation plane mirror 6; the light returns from the primary path of the plane mirror 6, sequentially passes through the primary mirror 5, the secondary mirror 4 and the three mirrors 3, passes through the compensator 2 again, and finally converges to the interferometer focus 1 to form an off-axis three-reflector auto-collimation interference light path with the compensator.
The number of the optical flat plates 2 is one or more, and the materials are selected according to the working wave band of the interferometer and are subjected to optical coating treatment.
The thickness calculation method of the optical flat plate 2 comprises the following steps:
1) In optical design software, a configuration I is established, an optical path model is an off-axis three-reflector optical system original system, and the optical path model comprises an off-axis three-reflector optical system, a window, an optical filter and a color separation film optical element, and all parameters are kept unchanged, namely the configuration I has no design variables and plays a role in constraint;
2) Establishing a configuration II, wherein the light path model is an off-axis three-mirror optical system and a compensator, and three parameters are used as design variables of the configuration II, namely the thickness of the compensator 2, the distance from the compensator 2 to the focal point 1 of the interferometer and the distance from the compensator 2 to the vertex of the three mirrors 3;
3) Establishing a configuration III, wherein the light path model is an off-axis three-mirror optical system and a compensator, the thickness of the compensator 2 is the same as the corresponding parameters of the configuration II, and simultaneously, two interval parameters of the reflecting mirror, the distance from the compensator 2 to the focal point 1 of the interferometer and the distance from the compensator 2 to the vertex of the three mirrors 3 are used as design variables of the configuration III;
4) The method comprises the steps of establishing a configuration IV, and an off-axis three-reflector optical system original system, wherein the original system comprises a window, an optical filter, a color separation film and other elements, two interval parameters of a reflector are identical to two corresponding parameters of the configuration III, and only a rear intercept is used as a design variable of the configuration IV;
5) And simultaneously optimizing each design variable of the configurations I, II, III and IV by minimizing wave aberration, so as to obtain the optimal thickness and reflection position parameters of the optical compensator.
The technical effect of this patent is as follows:
(a) The compensator is a small-caliber optical plain film, has a small clear aperture, can be made into a conventional size of about 25-50 mm, can be independently assembled by utilizing a self-forming module of the compensator installed by the existing optical clamping apparatus, is integrated with an auto-collimation interference light path, has a simple compensation structure, and is convenient for the assembly and test of an off-axis three-reflector system.
(b) The system compensator is close to the focus of the interferometer, insensitive to thickness and angle errors and insensitive to installation distance errors, and the requirement of system adjustment test can be met only by properly controlling the thickness error of the compensator, so that the processing and testing difficulty of the compensator is extremely low.
(c) The compensation effect is obvious, the method is particularly suitable for the adjustment test of the off-axis three-reflection optical system of the medium-wave infrared or long-wave infrared off-axis three-reflection optical system, and the back optical path is provided with a window sheet, a color separation sheet and other flat plate elements, and the defects of the existing method are overcome.
Drawings
Fig. 1 is a schematic diagram of an off-axis three-mirror optical system auto-collimation interferometry with a compensator.
Fig. 2 is a diagram of a long-wave infrared off-axis three-mirror optical system with a window and a filter.
Fig. 3 is a long wave infrared off-axis three-mirror optical system tuned with a compensator.
Detailed Description
The patent provides a compensator structure for off-axis three-reflector optical system adjustment test, which is characterized in that in an auto-collimation interference light path formed by an interferometer and a measured off-axis three-reflector optical system, an optical flat plate with proper thickness is placed in front of a focus of the interferometer, and the equivalent substitution and aberration compensation effects on the off-axis three-reflector light path parallel flat plate type optical element are realized.
The thickness design of the optical slab compensator is a key step in the design of the compensator and is the subject matter of claim (5).
The specific implementation steps of the thickness design of the optical flat compensator are as follows:
in the optical design software, a configuration I is established, an optical path model is an off-axis three-reflector optical system original system, and comprises an off-axis three-reflector optical system, a window, an optical filter, a color separation film and other optical elements, and all parameters are kept unchanged, namely the configuration I has no design variables;
step (b) establishing a configuration II, wherein the light path model is an off-axis three-mirror optical system and a compensator, and the thickness of the compensator 2, the distance from the compensator 2 to the focal point 1 of the interferometer and the distance from the compensator 2 to the vertex of the three mirrors (3) are used as design variables of the configuration II;
step (c) establishing a configuration III, wherein the light path model is an off-axis three-mirror optical system and a compensator, the thickness of the compensator 2 is the same as the corresponding parameters of the configuration II, and meanwhile, two interval parameters of the reflecting mirror, the distance from the compensator 2 to the focal point 1 of the interferometer and the distance from the compensator 2 to the vertex of the three mirrors 3 are used as design variables of the configuration III;
step (d), establishing a configuration IV, and an off-axis three-reflection optical system original system, wherein the original system comprises elements such as a window, an optical filter, a color separation film and the like, two interval parameters of a reflecting mirror are the same as two corresponding parameters of the configuration III, and only a rear intercept is used as a design variable of the configuration IV;
and (e) simultaneously optimizing each design variable of the configurations I, II, III and IV by minimizing wave aberration, so as to obtain the optimal thickness and reflection position parameters of the optical compensator.
And optimizing according to the steps to obtain optimal parameters such as the thickness, the clear aperture and the like of the compensator, selecting proper glass materials and coating according to the working wave band of the interferometer, and installing the interferometer at a proper position of the focus of the off-axis three-reflector auto-collimation optical path.
The key step of the thickness design of the optical flat compensator is to establish a reference and constraint relation between a design optical system and an adjustment test off-axis three-reflection optical system by utilizing the multiple configuration function of optical design software, and optimize the compensator parameters of the adjustment test optical path under the constraint of the design optical system so as to realize the optimal design of the compensator.
The parameters of the design of the example optical system are as follows:
effective aperture: 200.0mm;
angle of view: 12.0 °;
focal length: 400.0mm;
working wave band: 8.0-10.0 mu m.
The window is single crystal Germanium (germaninum) with a thickness of 8.0mm, and the filter uses single mirror Germanium (germaninum) with a thickness of 1.0 mm. The initial design parameters of the optical system are as follows:
based on the initial optical path parameters, the required optical system is obtained through proper optimization and proper constraint conditions.
Based on the final optical design model, an optical compensator is modeled to include four configuration states
The original optical design is configured (I) without optimization variables.
Three mirrors and compensators are configured (II). The optical compensator adopts quartz (Silica), wherein three parameters are set as optimization variables in total, namely the distance from a three-mirror to the compensator, the distance from the compensator to the interferometer and the thickness of the compensator.
Configuring (III) three reflectors and a compensator, wherein the thickness of the compensator is equal to the corresponding parameters of configuration (II), and wherein two spacing parameters of the three reflectors, the distance from the compensator to the focal point of the interferometer, and the distance from the compensator to the vertex of the three reflectors are set as optimization variables.
The original optical design of the configuration (IV) is configured, wherein two interval parameters of the three reflectors are equal to corresponding parameters of the configuration (III), and the rear intercept is set as an optimization variable. Other parameters remain unchanged as configuration (I).
The design variables of configurations I, II, III and IV were simultaneously optimized with wave aberration minimization, resulting in an optimal optical flat compensator thickness of 3.79mm. The compensator is used for adjusting the auto-collimation light path, and the interval variation of the three reflectors of the off-axis optical system is only 0.25mm and 0.09mm.
And (3) adjusting the three reflectors by using a quartz optical flat compensator with the thickness of 3.79mm to obtain the state of the optical system consistent with the design value. The off-axis three-reflection state is substituted into the original system light path again, and imaging quality parameters such as the diffuse speckles and the optical transfer function are consistent with the original system light path.
The compensator is not used for adjusting the auto-collimation optical path, the interval variation of the three reflectors of the off-axis optical system is 2.77mm and 1.37mm, the corresponding back intercept variation is 34.88mm,
the accuracy and feasibility of the compensator structure and the design method of the patent are proved by the verification of the practical adjustment test, wherein the compensating sheet can be fixed in front of the focus of the interferometer by adopting a lens clamp, a two-dimensional linear sliding table and other goods shelf products.
In summary, the present patent provides a structure and a design method of an off-axis three-reflector optical system compensator, wherein an optical compensator is added to a focus of an interferometer based on an off-axis three-reflector auto-collimation interferometry optical path, which can replace an optical path difference of optical elements such as a window filter of a rear optical path, and can compensate an aberration of the optical element of the rear optical path, so that an adjustment test of the off-axis three-reflector optical system can be smoothly performed, and a state closest to a predetermined optical path is obtained.
The compensator design method can be further popularized, can be used for the compensator design of the off-axis three-reflector optical system auto-collimation optical path with the lens group in the rear optical path, is subjected to adjustment test, and has wider applicability.
The above description is only one general embodiment of the present patent, and is not intended to limit the present patent, but any modifications, equivalents, improvements, etc. that fall within the spirit and principles of the present patent are intended to be included in the scope of the present patent.
Claims (2)
1. An off-axis three-mirror optical system compensator is characterized in that,
an optical flat plate with a certain thickness is inserted in front of an interferometer focus of an auto-collimation interference light path of an off-axis three-reflector optical system to be used as a compensator (2);
light rays emitted by the interferometer pass through the compensator (2) in a divergent manner through the focus (1), sequentially pass through the three mirrors (3), the secondary mirror (4), the main mirror (5) and are incident to the auto-collimation plane mirror (6); then the light returns from the primary path of the plane mirror (6), sequentially passes through the primary mirror (5), the secondary mirror (4) and the three mirrors (3), passes through the compensator (2) again, and finally converges to the interferometer focus (1) to form an off-axis three-reflector auto-collimation interference light path with the compensator.
2. The off-axis three-mirror optical system compensator of claim 1, wherein the compensator (2) is one or more optical plates, the material being selected and optically coated according to the operating band of the interferometer.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202222422741.1U CN218974671U (en) | 2022-09-14 | 2022-09-14 | Off-axis three-reflector optical system compensator |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202222422741.1U CN218974671U (en) | 2022-09-14 | 2022-09-14 | Off-axis three-reflector optical system compensator |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN218974671U true CN218974671U (en) | 2023-05-05 |
Family
ID=86155608
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202222422741.1U Active CN218974671U (en) | 2022-09-14 | 2022-09-14 | Off-axis three-reflector optical system compensator |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN218974671U (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116699864A (en) * | 2023-07-31 | 2023-09-05 | 中国科学院长春光学精密机械与物理研究所 | Reference-free adjustment method, device, equipment and medium for space-based large optical system |
-
2022
- 2022-09-14 CN CN202222422741.1U patent/CN218974671U/en active Active
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116699864A (en) * | 2023-07-31 | 2023-09-05 | 中国科学院长春光学精密机械与物理研究所 | Reference-free adjustment method, device, equipment and medium for space-based large optical system |
| CN116699864B (en) * | 2023-07-31 | 2023-10-20 | 中国科学院长春光学精密机械与物理研究所 | Reference-free adjustment method, device, equipment and medium for space-based large optical system |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN110567393B (en) | Large-curvature-radius free-form surface mirror surface shape interference measurement device and method | |
| Delorme et al. | Keck Planet Imager and Characterizer: a dedicated single-mode fiber injection unit for high-resolution exoplanet spectroscopy | |
| CN110350386B (en) | Low-noise high-stability deep ultraviolet continuous wave laser | |
| CN218974671U (en) | Off-axis three-reflector optical system compensator | |
| CN104697464B (en) | The interference detection method of large-caliber convex aspheric surface speculum based on offset lens | |
| CN110737103B (en) | Large-caliber off-axis catadioptric multichannel optical system assembling and adjusting method | |
| WO2005078385A1 (en) | Surface shape measurement apparatus and method | |
| CN109253707B (en) | Hundred-micrometer range transmission type interference testing device | |
| CN111077076B (en) | Medium wave infrared Fourier transform imaging spectrometer athermal secondary imaging system | |
| CN109253864A (en) | It is a kind of for examining the optical system of super large caliber convex hyperboloid mirror | |
| Burge et al. | Measurement of aspheric mirror segments using Fizeau interferometry with CGH correction | |
| CN111006851B (en) | Wavefront detection device and method for edge sub-mirror in splicing mirror | |
| CN115508992A (en) | Off-axis three-mirror optical system compensator and design method thereof | |
| CN114216659A (en) | System and method for measuring parallelism of large-caliber long-focus optical axis | |
| US20100202055A1 (en) | Diffraction order sorting filter for optical metrology | |
| Mourard et al. | CHARA/SPICA: a six-telescope visible instrument for the CHARA Array | |
| CN112902875B (en) | Aspheric reflector curvature radius detection device and method | |
| CN212364710U (en) | Large-view-field off-axis three-reflection type collimator optical system | |
| CN111596451A (en) | Large-view-field off-axis three-reflection type collimator optical system | |
| Olivier et al. | Optical design of the LSST camera | |
| CN111190286B (en) | Optical system for checking concave aspheric mirror by combining front-back zero compensation and design method | |
| CN209446259U (en) | For examining the optical system of super large caliber convex hyperboloid mirror | |
| US10976249B1 (en) | Reflective pupil relay system | |
| CN112748558A (en) | Wide-spectrum large-dynamic-range optical system and test calibration method | |
| Kilaru et al. | Development of multi-beam long trace profiler |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| GR01 | Patent grant | ||
| GR01 | Patent grant |