1994 Fiscal Year Final Research Report Summary
Profile Measurement of Asymmetrical Aspherical Surfaces
| Project/Area Number |
05452140
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
機械工作・生産工学
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| Research Institution | Tokyo Metoropolitan University, Faculty of Engineering |
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Principal Investigator |
HARADA Tatsuo Tokyo Metr, Univ., Fac.of Eng., Professor, 工学部, 教授 (70244415)
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| Co-Investigator(Kenkyū-buntansha) |
SAKUMA Hideo Tokyo Metr.Univ., Fac.of Eng., Research Assistant, 工学部, 助手 (20128573)
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| Project Period (FY) |
1993 – 1994
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| Keywords | Asymmetrical aspherical surface / Toroidal surface / Cylindrical surface / Grazing incidence system / Profile measurement / Laser interferometer / Soft x-ray optics |
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| Research Abstract |
The purpose of this research is to evaluate the profiles of asymmetrical aspherical surfaces such as palaboroidal, ellipsoidal and toroidal surfaces with the same accuracy as those of plane and spherical surfaces. These aspherical surfaces are usually used to focus soft x-rays and extreme ultraviolet radiations in grazing incidence optical systems.
The fundamental idea of this newly proposed measurement system is to use laser interfermeter and optical image processing. An asymmetrical aspherical mirror to be measured forms a grazing incidence system so as to focus incident radiation to a point. The grazing incidence system is mounted in a laser interferometer. The fringe pattern obtained with the laser interferometer shows the difference between the wavefront from the grazing incidence system and that with stigmatic focus, corresponding to the profile error of the aspherical surface. Parabolodal and ellipsoidal surfaces satisfy ideal stigmatic focal condition, however, toroidal surface does not. When measuring toroidal surface, the profile difference between the toroid and an ellipsoid is calculated in advance and the profile error of toroidal surface is obtained by subtracting the difference from the total profile obtained from the fringe patern.
In experiment, ZYGO MARKII laser interferometer system and ZYGO ZYMOD/PC analytical system are used as a measurement system and profile errors of a toroidal and a cylindrical surfaces are measured.
The new measurement system enables the display of total error map of an asymmetrical aspherical surface with the resolution of laser interferometer and the effectiveness is shown especially in a twisted shape of toroid and a taped shape of cylinder. The measurement system can be applied for the evaluation of surface profile generated by active optics which obtains an optical surface profile by elastic diformation of a solid blank.
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Research Products
(2 results)
