| 摘要 |
A method of constructing a thin film mirror, which method comprises: (i) attaching a thin film (72) to a suction chamber (68), the suction chamber (6 8) having edges which are for attaching the thin film (72) and which lie in a desired geometry for the thin film mirror to be constructed; (ii) applying a partial vacuum to the suction chamber (68) such that tension is introduced into the thin film (72); (Hi) adjusting the partial vacuum to form the thin film mirror but with the thin film mirror achieving the desired geometry onl y over a portion of the thin film mirror; (iv) providing first tensioning mean s (78, 80) and locally adjusting the first tensioning means (78, 80) such that the portion of the thin film mirror which achieves the desired geometry is increased, the first tensioning means (78, 80) being in contact with the surface of the thin film (72) adjacent to the edge of the suction chamber (6 8) at a first distance which is substantially uniform from the edge of the suction chamber (68); and providing second tensioning means (82, 84) and locally adjusting the second tensioning means (82, 84) such that the portion of the thin film mirror which achieves the desired geometry is further increased, the second tensioning means (82, 84) being in contact with the surface of the thin film (72) adjacent to the first tensioning means (78, 80 ) at a second distance which is substantially uniform from the edge of the suction chamber (68), and which second distance is greater than the first distance from the edge of the suction chamber (68) of the first tensioning means (78, 80).
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