Patent ID: 6945659

Claim:
Apparatus for constructing a thin film mirror, which apparatus comprises a suction chamber, first attachment means positioned at a first side of the suction chamber and for attaching the thin film to the first side of the suction chamber, and second attachment means positioned at a second and opposite side of the suction chamber and for attaching the thin film to the second side of the suction chamber, characterised in that the first and second attachment means are such that they secure the thin film against movement when tension is applied in a first direction extending between the first and second attachment means; the first and second attachment means are such that they allow the thin film to move and stretch in a second direction which is at right angles to the first direction and which allows the thin film to be distorted to a desired geometric shape for forming the thin film mirror; the first attachment means comprises a flexible retaining strip, and an attachment member which has first and second ends, the first end being such that it passes partially around the flexible retaining strip, and the second end being such that it is secured to the suction chamber; and the second attachment means comprises a flexible retaining strip, and an attachment member which has first and second ends, the first end being such that it passes partially around the flexible retaining strip, and the second end being such that it is secured to the suction chamber.