A deformable mirror including: a flexible member including a reflective surface for reflecting light incident thereupon; and a reference surface substrate including a support portion for supporting a peripheral portion of the flexible member, and a curved portion provided inside the support portion, the curved portion providing a space for allowing for the flexible member to be elastically deformed. A height of a central portion of the curved portion of the reference surface substrate is set to be equal to or less than a height of the support portion of the reference surface substrate. The flexible member is elastically deformed by being drawn toward the curved portion of the reference surface substrate, thereby giving a predetermined aberration to light incident upon the reflective surface of the flexible member.

Variable focus optical devices, in particular lenses, can include a cavity at least partially defined by a flexible membrane (2), which may be retained between engaging portions of a frame member (8) and a ring member (12), such that a peripheral region of the membrane is caused to change direction more than twice. The engaging portions of the ring and frame may be high-friction surfaces. In addition, methods of filling a cavity of a lens with transparent fluid, methods of adjusting the pressure of fluid in the cavity, and methods of sealing such a cavity are described, as well the use of such lenses in adjustable spectacles.

A mirror module system is provided for accurately focusing solar radiation on a point or a line as defined by an array of solar collectors. Each mirror module includes a flexible membrane stretched over a frame in a manner similar to that of a drum or a trampoline and further includes a silvered glass or plastic mirror for forming an optical reflecting surface. The configuration of the optical reflecting surface is variably adjustable to provide for the accurate focusing of the solar energy on a given collector array, e.g., a point or a linear array arrangement. The flexible mirror-membrane combination is lightweight to facilitate installation and reduce system cost yet structurally strong enough to provide for the precise focusing of the incident solar radiation in a semi-rigid reflector system in which unwanted reflector displacement is minimized.

A mirror which is incorporated in an optical device and is made of plastic, comprising: an effective portion which has a constant thickness and a reflecting surface; and a reinforcing portion which is so provided as to enclose the effective portion and reinforces the effective portion from a periphery of the effective portion; the reinforcing portion being formed integrally with the effective portion; the reinforcing portion having a thickness equal to the thickness of the effective portion; the reinforcing portion having a constant width.

A thin reflecting disk tightly bears on one edge of a case for defining a closed volume, means being provided in the latter for producing a negative pressure, and the bottom of the case is provided with supports arranged in parallel rows of three supoprts, a small beam being advantageously interposed between the disk and each row of supports when this mirror is used for focusing a laser beam, it is possible, by simply regulating the supports, to modify the shape of the disk so as to, e.g. obtain a rectilinear focal zone and a constant energy concentration of the beam along the zone.