CN108388023B - A high-precision assembly system for a large-aperture wide-spectrum F-P tunable filter - Google Patents

Abstract

The inventionThe assembly system mainly comprises a fixed mirror installation module, a movable mirror installation module, a piezoelectric inertia driver, a three-dimensional micro-displacement platform and a two-dimensional electric displacement platform, wherein the initial cavity length of an F-P cavity and the parallelism between reflecting mirror surfaces are accurately set by adopting a coarse adjustment, fine adjustment and fine adjustment triple adjustment mechanism for adjustment, the cavity length adjustment resolution can reach 10nm level, and the parallelism between two reflecting mirror surfaces in the cavity can reach 10^‑1 μ rad. The high-precision assembly system has high displacement positioning precision and high parallelism adjusting capability, and can ensure that the initial cavity length of the F-P cavity of the F-P tunable filter with large caliber and wide spectral range and the parallelism between the reflecting mirrors meet the requirements of hyperspectral remote sensing application.

Description

Translated fromChinese

一种大口径宽光谱F-P可调谐滤波器的高精密装配系统A high-precision assembly system for a large-aperture wide-spectrum F-P tunable filter

技术领域technical field

本发明涉及F-P可调谐滤波器，特别涉及一种大口径宽光谱范围F-P可调谐滤波器的高精密装配系统。The invention relates to an F-P tunable filter, in particular to a high-precision assembly system for a large-aperture wide-spectral range F-P tunable filter.

背景技术Background technique

高光谱遥感技术以“图谱合一”的特点和强大的信息获取能力，在地球科学、国防安全、环境监测和深空探测等诸多应用领域表现优异。近年来，高光谱遥感技术在无人机系统、小卫星有效载荷等某些特殊技术领域的应用，对成像光谱仪的小型化、轻量化提出了更高的要求。Hyperspectral remote sensing technology has excellent performance in many application fields such as earth science, national defense security, environmental monitoring and deep space exploration with the characteristics of "map-spectrum integration" and powerful information acquisition capabilities. In recent years, the application of hyperspectral remote sensing technology in some special technical fields such as unmanned aerial vehicle systems and small satellite payloads has put forward higher requirements for the miniaturization and weight reduction of imaging spectrometers.

分光技术是高光谱遥感技术中的核心关键技术之一，现有的高光谱成像仪多基于棱镜-光栅-棱镜组件或光栅分光^[1-3]，分光系统占据空间较大，导致整机的重量较重。成像光谱仪更小更轻的发展趋势对分光技术提出了更高的要求。Spectroscopic technology is one of the core key technologies in hyperspectral remote sensing technology. Existing hyperspectral imagers are mostly based on prism-grating-prism components or grating light splitting^[1-3] . Heavy weight. The development trend of smaller and lighter imaging spectrometers puts forward higher requirements for spectroscopic technology.

法布里-珀罗干涉仪(Fabry-Perot Interferometer,FPI)是利用多光束干涉原理进行光谱选择的分光器件，在超精细光谱结构分析领域应用广泛^[4]。Fabry-Perot(F-P)可调谐滤波器(Tunable Fabry-Perot Filters，TFPF)利用F-P腔的通带波长可随其腔长变化的特点，实现可调滤波。The Fabry-Perot Interferometer (FPI) is a spectroscopic device that uses the principle of multi-beam interference for spectral selection, and is widely used in the field of ultra-fine spectral structure analysis^[4] . Fabry-Perot (FP) tunable filters (Tunable Fabry-Perot Filters, TFPF) utilize the characteristic that the passband wavelength of the FP cavity can change with its cavity length to realize tunable filtering.

TFPF主要由平行放置的内表面镀有高反射率膜层的两块透明平板组成，平板之间的空气间隙利用微小的压电陶瓷块调节。TFPF构型扁平，结构紧凑简单，体积小，重量轻，在光谱成像系统中使用时可以放置在平行光路里，也可直接置于探测器前。采用TFPF分光可大大简化成像光谱仪的分光系统，大幅降低高光谱成像仪的体积、重量和功耗。The TFPF is mainly composed of two transparent flat plates whose inner surfaces are coated with a high-reflectivity film layer placed in parallel, and the air gap between the flat plates is adjusted by a tiny piezoelectric ceramic block. TFPF has a flat configuration, compact and simple structure, small size, and light weight. When used in a spectral imaging system, it can be placed in the parallel optical path or directly in front of the detector. The use of TFPF spectroscopy can greatly simplify the spectroscopic system of the imaging spectrometer, and greatly reduce the volume, weight and power consumption of the hyperspectral imager.

TFPF作为可扫描的分光元件在高光谱遥感系统中使用时，其通光孔径通常需要达到几十个mm，为保证宽的工作光谱范围(≥500nm)和nm级的光谱分辨率，F-P腔的腔长要小至μm尺度甚至更小，腔内反射镜面间要维持优于10^-1μrad级的平行度。为了使器件尽量轻薄，TFPF选用的压电陶瓷块的厚度一般为2～3mm，其最大输出位移仅为数μm，若F-P腔内不同位置的空气间隙厚度差异或腔长的实际需要调整量超出了压电致动器的最大输出位移，则压电致动器将失去对腔长和镜面间平行度的有效调节能力。When TFPF is used as a scannable spectroscopic element in a hyperspectral remote sensing system, its clear aperture usually needs to reach tens of mm. In order to ensure a wide operating spectral range (≥500nm) and nm-level spectral resolution, the FP cavity The length of the cavity should be as small as μm scale or even smaller, and the parallelism between mirror surfaces in the cavity should be maintained better than 10^-1 μrad level. In order to make the device as light and thin as possible, the thickness of the piezoelectric ceramic block selected by TFPF is generally 2-3 mm, and its maximum output displacement is only a few μm. If the maximum output displacement of the piezoelectric actuator is exceeded, the piezoelectric actuator will lose the ability to effectively adjust the cavity length and the parallelism between the mirrors.

如何对大尺寸TFPF进行高精密的装配，确保F-P腔的初始腔长和反射镜面间平行度达到设定的技术指标要求，是TFPF实现nm级高光谱分辨率可调滤波的前提。How to carry out high-precision assembly of large-size TFPF to ensure that the initial cavity length of the F-P cavity and the parallelism between mirror surfaces meet the set technical index requirements is the premise for TFPF to realize nm-level high spectral resolution adjustable filtering.

参考文献references

[1]王欣，杨波，丁学专.空间遥感短波红外成像光谱仪的光学系统设计[J].红外技术，2009，31(12)：687-690[1] Wang Xin, Yang Bo, Ding Xuezhuan. Optical system design of short-wave infrared imaging spectrometer for space remote sensing [J]. Infrared Technology, 2009, 31(12): 687-690

[2]袁立银，何志平，舒嵘.短波红外棱镜-光栅-棱镜成像光谱仪光学系统设计[J].光子学报，2011，40(6)：831-834[2] Yuan Liyin, He Zhiping, Shu Rong. Optical system design of short-wave infrared prism-grating-prism imaging spectrometer [J]. Acta Photonica Sinica, 2011, 40(6): 831-834

[3]薛庆生，林冠宇，宋克非.星载大视场短波红外成像光谱仪光学设计[J].光子学报，2011，40(5)：673-678[3] Xue Qingsheng, Lin Guanyu, Song Kefei. Optical Design of Spaceborne Large Field of View Shortwave Infrared Imaging Spectrometer [J]. Acta Photonica Sinica, 2011, 40(5): 673-678

[4]郑植仁.光学[M].哈尔滨：哈尔滨工业大学出版社，2006：124[4] Zheng Zhiren. Optics [M]. Harbin: Harbin Institute of Technology Press, 2006: 124

发明内容Contents of the invention

本发明针对大尺寸宽光谱范围TFPF的F-P腔μm级腔长和腔内反射镜面间10^-1μrad级的平行度的装配要求，提出了一种大口径宽光谱范围TFPF的高精密装配系统。The present invention proposes a high-precision assembly system for a large-diameter wide-spectrum range TFPF, aiming at the assembly requirements of the μm-level cavity length of the FP cavity of the large-size wide-spectrum range TFPF and the^10-1 μrad-level parallelism between the reflection mirrors in the cavity.

如图1所示，本发明所述的大口径宽光谱范围TFPF的高精密装配系统包括定镜安装模块1、动镜安装模块2、三维微位移平台3、压电惯性驱动器6和二维电动位移台7。As shown in Figure 1, the high-precision assembly system of the large-aperture wide-spectrum range TFPF described in the present invention includes a fixedmirror installation module 1, a movingmirror installation module 2, a three-dimensionalmicro-displacement platform 3, a piezoelectricinertial driver 6 and a two-dimensionalelectric motor Stage 7.

其中，定镜安装模块1的光学调整架可以在俯仰和偏摆方向提供±4°的角度调整，在垂直于镜架光轴的平面内360°可旋转，并具有2°的旋转分度；Among them, the optical adjustment frame of the fixedmirror installation module 1 can provide an angle adjustment of ±4° in the pitch and yaw directions, can rotate 360° in a plane perpendicular to the optical axis of the mirror frame, and has a rotation index of 2°;

动镜安装模块2的光学调整架具备3个1/4英寸-80调节螺丝，可以提供俯仰和偏摆方向提供±4°的角度调整，能够与压电惯性驱动器6兼容；The optical adjustment frame of the movingmirror installation module 2 has three 1/4 inch-80 adjustment screws, which can provide ±4° angle adjustment in the pitch and yaw directions, and can be compatible with the piezoelectricinertial driver 6;

三维微位移平台3，含有三组位移调节器，每组位移调节器均由粗调节器4和微调节器5组成，粗调节器4具备mm量级的行程，每转的粗调范围为500μm，微调节器5具备100μm量级的行程，每转的微调范围是50μm；The three-dimensionalmicro-displacement platform 3 contains three sets of displacement regulators, each set of displacement regulators consists of a coarse regulator 4 and a fine regulator 5, the coarse regulator 4 has a stroke of mm order, and the coarse adjustment range per revolution is 500 μm , the micro-adjuster 5 has a stroke of the order of 100 μm, and the fine-tuning range per revolution is 50 μm;

压电惯性驱动器6，带有1/4"-80安装螺纹，可兼容动镜安装模块2中的光学调整架，具备10mm行程，在闭环控制下可以达到20nm的典型步长；Piezoelectric inertia driver 6, with 1/4"-80 mounting thread, compatible with the optical adjustment mount in the movingmirror mounting module 2, with a stroke of 10mm, and a typical step size of 20nm under closed-loop control;

二维电动位移台7在竖直方向和水平方向的行程均不小于1英寸，位移分辨率优于1μm，重复定位精度优于5μm；The vertical and horizontal strokes of the two-dimensionalelectric translation stage 7 are not less than 1 inch, the displacement resolution is better than 1 μm, and the repeat positioning accuracy is better than 5 μm;

所述的压电惯性驱动器6安装在动镜安装模块2中的光学调整架的3个1/4英寸-80调节螺丝的安装孔处；Thepiezoelectric inertia driver 6 is installed in the mounting holes of three 1/4 inch-80 adjustment screws of the optical adjustment frame in the movingmirror installation module 2;

所述的定镜安装模块1安装在二维电动位移台7上，三维微位移平台3安装在二维电动位移台7上，动镜安装模块2安装在三维微位移平台3上；The fixedmirror installation module 1 is installed on the two-dimensionalelectric displacement platform 7, the three-dimensionalmicro-displacement platform 3 is installed on the two-dimensionalelectric displacement platform 7, and the movingmirror installation module 2 is installed on the three-dimensionalmicro-displacement platform 3;

所述的定镜安装模块1与动镜安装模块2的光轴处于同一高度，且彼此相对平行放置。The optical axes of the fixedmirror installation module 1 and the movingmirror installation module 2 are at the same height, and are placed relatively parallel to each other.

本发明所述的大口径宽光谱范围TFPF的高精密装配系统对F-P腔腔长和镜面间平行度的调节主要由粗调、微调和精调三重调节机构实现。The adjustment of the F-P cavity length and the parallelism between the mirror surfaces of the high-precision assembly system of the large-aperture wide-spectrum range TFPF described in the present invention is mainly realized by a triple adjustment mechanism of coarse adjustment, fine adjustment and fine adjustment.

对TFPF进行装配时，分别将定镜和动镜装进定镜安装模块1和动镜安装模块2的光学调整架上，定镜安装模块1在调整好与光谱测试系统光轴的相对位置后保持不动，动镜安装模块2与定镜安装模块1之间平行放置，两个反射镜面彼此相对，二者之间相对位置的粗调和微调由三维微位移平台3实现。三维微位移平台3的粗调节器4可以使动镜安装模块2以较快的速度接近定镜安装模块1，微调节器5可以在动镜安装模块2接近定镜安装模块1时缓慢调节二者之间的相对位置，使动镜和定镜之间的距离达到F-P腔的初始腔长所在的量级。When assembling the TFPF, install the fixed mirror and the moving mirror into the optical adjustment brackets of the fixedmirror installation module 1 and the movingmirror installation module 2 respectively. After the fixedmirror installation module 1 is adjusted relative to the optical axis of the spectrum test system, Keeping still, the movingmirror installation module 2 and the fixedmirror installation module 1 are placed in parallel, and the two mirror surfaces face each other, and the rough adjustment and fine adjustment of the relative position between the two are realized by the three-dimensionalmicro-displacement platform 3 . The coarse adjuster 4 of the three-dimensionalmicro-displacement platform 3 can make the movingmirror installation module 2 approach the fixedmirror installation module 1 at a faster speed, and the fine adjuster 5 can slowly adjust the second when the movingmirror installation module 2 approaches the fixedmirror installation module 1. The relative position between them makes the distance between the moving mirror and the fixed mirror reach the order of the initial cavity length of the F-P cavity.

两个反射镜面上镀有电极，利用电容测微可以得到两个反射镜面间的距离和平行度的反馈信息，借助定镜安装模块1中光学调整架的旋转调整功能完成两反射镜上电极图形的对准。Electrodes are coated on the surface of the two mirrors, and the feedback information of the distance and parallelism between the two mirrors can be obtained by capacitance micrometry, and the electrode pattern on the two mirrors can be completed by means of the rotation adjustment function of the optical adjustment frame in the fixedmirror installation module 1 alignment.

F-P腔初始腔长的精确设定和平行度的精确调节由压电惯性驱动器6实现，动镜安装模块2可兼容三个压电惯性驱动器6。利用电容测微提供的镜面间隙反馈，可以对压电惯性驱动器6进行闭环控制，其位移分辨率可以达到20nm，能够使两反射镜面间距离调节的分辨率达到10nm量级，平行度达到10^-1μrad量级。The precise setting of the initial cavity length of the FP cavity and the precise adjustment of the parallelism are realized by the piezoelectricinertial driver 6 , and the movingmirror installation module 2 is compatible with three piezoelectricinertial drivers 6 . Using the mirror gap feedback provided by capacitive micrometry, the piezoelectricinertial driver 6 can be closed-loop controlled, and its displacement resolution can reach 20nm, and the resolution of the distance adjustment between the two reflecting mirrors can reach the order of 10nm, and the parallelism can reach 10^{- 1} μrad order of magnitude.

二维电动位移台7可以使动镜和定镜在垂直于光谱测试系统光轴的平面内进行整体平动，便于对TFPF有效通光孔径内的不同位置进行光谱测量和通带峰值波长的校准，二维电动位移台可以根据实际行程需要自由选择相应的匹配产品。The two-dimensionalmotorized translation stage 7 can make the moving mirror and the fixed mirror perform overall translation in the plane perpendicular to the optical axis of the spectrum testing system, which is convenient for spectrum measurement and passband peak wavelength calibration for different positions in the effective clear aperture of the TFPF , the two-dimensional electric translation stage can freely choose the corresponding matching product according to the actual travel needs.

本发明可以对大尺寸TFPF进行高精密的装配，该装配系统位移定位精度高，平行度调节能力强，能够确保TFPF的F-P腔初始腔长和反射镜面间平行度达到高光谱遥感应用要求。The invention can carry out high-precision assembly of large-size TFPF. The assembly system has high displacement positioning accuracy and strong parallelism adjustment ability, and can ensure that the initial cavity length of the F-P cavity of the TFPF and the parallelism between reflecting mirror surfaces meet the application requirements of hyperspectral remote sensing.

附图说明Description of drawings

图1为大口径宽光谱范围TFPF的高精密装配系统结构示意图。Figure 1 is a schematic diagram of the structure of a high-precision assembly system for a large-aperture wide-spectrum range TFPF.

具体实施方式Detailed ways

下面以30mm有效通光口径宽光谱范围TFPF的高精密装配系统为例对本发明做进一步的说明。The present invention will be further described below by taking a high-precision assembly system with 30mm effective aperture and wide spectral range TFPF as an example.

该装配系统中定镜安装模块1中的镜架、动镜安装模块2中的镜架、三维微位移平台3和压电惯性驱动器6型号分别为KS2RS、KS2、PIAK10和MBT616D/M，上述光机组件及与镜架匹配的接杆和底座均为Thorlabs公司生产；二维电动位移台7为卓立汉光生产的超薄型电动位移台TSA30-C和高精密电动升降台KSAV2030-ZF组装而成。In this assembly system, the models of the mirror frame in the fixedmirror installation module 1, the mirror frame in the movingmirror installation module 2, the three-dimensionalmicro-displacement platform 3 and thepiezoelectric inertia driver 6 are KS2RS, KS2, PIAK10 and MBT616D/M respectively. The machine components, the rods and bases that match the frame are all produced by Thorlabs; the two-dimensionalelectric translation stage 7 is assembled by the ultra-thin electric translation stage TSA30-C and the high-precision electric lifting table KSAV2030-ZF produced by Zhuoli Hanguang made.

对TFPF进行装配时，首先将定镜和动镜分别安装进定镜安装模块1和动镜安装模块2的光学调整镜架KS2RS和KS2上，然后将三个微小压电陶瓷块附接到定镜的相应位置上，压电陶瓷块的另一自由端均涂上适量的紫外固化胶。When assembling the TFPF, first install the fixed mirror and the moving mirror into the optical adjustment frame KS2RS and KS2 of the fixedmirror installation module 1 and the movingmirror installation module 2 respectively, and then attach three tiny piezoelectric ceramic blocks to the fixedmirror installation module 1 and the movingmirror installation module 2 respectively. On the corresponding position of the mirror, the other free end of the piezoelectric ceramic block is coated with an appropriate amount of UV-curable glue.

在TFPF装配过程中，位于定镜安装模块1和动镜安装模块2上的两反射镜的腔内反射镜面相对，二者平行放置。定镜安装模块1在调整好与光谱测试系统光轴的相对位置后保持不动，两反射镜之间相对位置的粗调和微调由三维微位移平台3调节。三维微位移平台3的粗调节器4行程4mm，可以使动镜安装模块2以500μm/rev的速度调整与定镜安装模块1的相对位置；微调节器5行程300μm，可以在动镜安装模块2接近定镜安装模块1时以50μm/rev的速度缓慢调节二者之间的相对位置，使两反射镜面之间的距离达到μm量级。During the TFPF assembly process, the intracavity mirror surfaces of the two mirrors located on the fixedmirror installation module 1 and the movingmirror installation module 2 face each other, and they are placed in parallel. The fixedmirror installation module 1 remains stationary after being adjusted relative to the optical axis of the spectrum testing system, and the rough adjustment and fine adjustment of the relative position between the two mirrors are adjusted by the three-dimensionalmicro-displacement platform 3 . The coarse adjuster 4 of the three-dimensionalmicro-displacement platform 3 has a stroke of 4mm, which can make the movingmirror installation module 2 adjust the relative position with the fixedmirror installation module 1 at a speed of 500μm/rev; 2 When themodule 1 is installed close to the fixed mirror, slowly adjust the relative position between the two at a speed of 50 μm/rev, so that the distance between the two mirror surfaces reaches the order of μm.

借助定镜安装模块1中光学调整架KS2RS的旋转调整功能完成两反射镜上电极图形的对准。The alignment of the electrode patterns on the two mirrors is completed by means of the rotation adjustment function of the optical adjustment frame KS2RS in the fixedmirror installation module 1.

F-P腔初始腔长的精确设定和平行度的精确调节借助动镜安装模块2上与光学调整架KS2兼容的压电惯性驱动器6完成。利用两反射镜面上测量电极提供的电容测微反馈，闭环控制下压电惯性驱动器6能够提供20nm的典型步长，可以使动镜和定镜之间距离调节的分辨率达到10nm量级，两反射镜面之间的平行度达到10^-1μrad量级。The precise setting of the initial cavity length of the FP cavity and the precise adjustment of the parallelism are accomplished by means of the piezoelectricinertial driver 6 on the movingmirror installation module 2 that is compatible with the optical alignment mount KS2. Using the capacitive micrometric feedback provided by the measuring electrodes on the two reflecting mirrors, the piezoelectricinertial driver 6 under closed-loop control can provide a typical step size of 20nm, and the resolution of the distance adjustment between the moving mirror and the fixed mirror can reach the order of 10nm. The parallelism between the reflecting mirrors reaches the order of 10^-1 μrad.

二维电动位移台7在竖直方向的行程为30mm，在水平方向的行程为30mm，可以使定镜安装模块1和动镜安装模块2整体在垂直于光谱测试系统光轴的平面内进行平动，便于对TFPF有效通光孔径内的不同位置进行光谱测量和通带峰位的校准。The stroke of the two-dimensionalelectric translation stage 7 in the vertical direction is 30mm, and the stroke in the horizontal direction is 30mm, so that the fixedmirror installation module 1 and the movingmirror installation module 2 can be aligned in a plane perpendicular to the optical axis of the spectrum testing system. It is convenient to perform spectral measurement and passband peak calibration for different positions within the effective aperture of the TFPF.

在两反射镜面之间的距离和平行度达到设定的F-P腔初始腔长和镜面间平行度要求时，利用紫外灯同时将所有紫外固化胶固化，使压电陶瓷块附接至动镜，完成TFPF的装配。When the distance and parallelism between the two reflecting mirrors meet the set F-P cavity initial cavity length and parallelism requirements between the mirrors, all the UV-curing glues are cured at the same time by the UV lamp, so that the piezoelectric ceramic block is attached to the moving mirror, Complete the assembly of TFPF.

Claims (1)

1. A high-precision assembly system of a large-caliber wide-spectrum F-P tunable filter comprises a fixed mirror installation module (1); a movable mirror mounting module (2); a three-dimensional micro-displacement platform (3); a piezoelectric inertial drive (6); a two-dimensional electric displacement table (7); the method is characterized in that:

the optical adjusting frame of the fixed mirror mounting module (1) provides an angle adjustment of +/-4 degrees in the pitching and swaying directions, is rotatable by 360 degrees in a plane perpendicular to the optical axis of the mirror frame and has a rotation index of 2 degrees;

the optical adjusting frame of the moving mirror mounting module (2) is provided with 3 1/4 inch-80 adjusting screws, and the pitching and swaying directions provide angle adjustment of +/-4 degrees and can be compatible with the piezoelectric inertia driver (6);

the three-dimensional micro-displacement platform (3) comprises three groups of displacement regulators, each group of displacement regulators consists of a coarse regulator (4) and a fine regulator (5), the coarse regulator (4) has a stroke of 4mm, the coarse regulation range of each rotation is 500 mu m, the fine regulator (5) has a stroke of 300 mu m, and the fine regulation range of each rotation is 50 mu m;

the piezoelectric inertial driver (6) is provided with 1/4 inch-80 mounting threads, is compatible with an optical adjusting frame in the moving mirror mounting module (2), has a stroke of 10mm magnitude, and has a step length of 20nm under closed-loop control;

the stroke of the two-dimensional electric displacement table (7) in the vertical direction and the horizontal direction is not less than 1 inch, the displacement resolution is less than 1 mu m, and the repeated positioning precision is less than 5 mu m;

the piezoelectric inertia driver (6) is arranged at the mounting holes of 3 1/4 inch-80 adjusting screws of the optical adjusting frame in the moving mirror mounting module (2);

the fixed mirror installation module (1) is installed on the two-dimensional electric displacement platform (7), the three-dimensional micro-displacement platform (3) is installed on the two-dimensional electric displacement platform (7), and the movable mirror installation module (2) is installed on the three-dimensional micro-displacement platform (3);

the optical axes of the fixed mirror installation module (1) and the movable mirror installation module (2) are positioned at the same height and are arranged in parallel relatively to each other.

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