Mirror having a variable focal length
AssigneeQuantel Limited
InventorsGeorges Bret, Guy Michelet
Life of this patent
Estimating the term…
Abstract
The mirror comprises a multilayer structure, at least one of the component layers of which is made from a piezoelectric material, and electrodes for applying voltage to the multilayer structure. A free face of the multilayer structure carries the reflecting surface of the mirror. At least one of the outer faces of the mirror comprises at least one zone of curvature which is non-zero in the non-excited state of the multilayer structure.
Claims19
A mirror having a reflecting surface, the entire area of which is intended to selectively focus an image reflected thereby in a continuously variable focal plane, the variation of which is obtained by a deformation of the structure of that mirror, the latter comprising a multilayer structure at least one component of the component layers of which is made from piezoelectric material the thickness of the entire multilayer structure being in the order of magnitude of one millimeter, and electrodes combined with said multilayer structure for applying voltage to said multilayer structure, said multilayer structure having an outer face, said reflecting surface being provided on said outer face, the mirror constructed in this way having outer faces at least one of which outer faces comprises at least one zone having a given curvature in the non-excited state of said multilayer structure, whereby said electrodes are connected to terminals adapted to be supplied with a selectively variable voltage the variation of which causes said image to be selectively focused in said focal plane.
A mirror comprising:
- a reflecting surface having a prescribed area;
- means for selectively focusing an image reflected from the entire prescribed are in a focal plane having a focal length which is variable over a continuous range of focal lengths, said means comprising:
- a multilayer structure for said mirror wherein at least one layer of the structure is made of piezoelectric material, said multilayer structure having first and second outer faces, said first outer face corresponding to said reflecting surface, said multilayer structure being sufficiently thin to permit it to be curved over a continuous curvature range from a non-excited state in response to application of a variable voltage to said multilayer structure, wherein at least one of said outer faces includes at least one zone having a finite curvature in said non-excited;
- and
- electrode means connected to said multilayer structure for applying a selectively variable voltage to said multilayer structure to vary the curvature of said reflecting surface as a function of the applied voltage.
Dependencies are inferred from the claim text.