US 5,616,066 A · Magnetorheological finishing of edges of optical elements

Abstract

Method and apparatus using magnetorheological fluid for finishing a non-image-forming edge of an optical element to a very high degree of smoothness and for removing microscopic fissures from such edges, the method comprising positioning an optical element near a continuous carrier surface such that a converging gap is defined between an edge of the optical element and the carrier surface, the element being disposed such that image-forming refractive and reflective surfaces thereof do not create a gap with the carrier surface; applying a magnetic field substantially at the gap; introducing a magnetorheological fluid onto the carrier surface; driving the magnetorheological fluid through the gap to cause a flow of magnetic field-stiffened magnetorheological fluid through this gap to create a work zone and to form a transient finishing tool for removing material from the edge of the optical element; and moving the optical element relative to the work zone to expose different portions of the edge to the fluid for predetermined time periods to finish the edge to a predetermined degree. The lateral extent of fluid may be broad enough to permit polishing of a plurality of optical elements simultaneously on a single carrier surface, or a plurality of finishing stations may be ganged to finish a plurality of optical elements on a plurality of carrier surfaces.

Claims31

Dependent claims

A method of finishing an edge of an optical element using magnetorheological fluid, comprising:

a) positioning an optical element near a carrier surface such that a converging gap is defined between an edge of said optical element and said carrier surface, said element being positioned to exclude definition of a converging gap between image-forming refractive and reflective surfaces of said element and said carrier surface;
b) applying a magnetic field substantially at said gap;
c) introducing a magnetorheological fluid onto said carrier surface near said gap, said fluid being stiffened in said magnetic field;
and
d) providing first relative motion between said carrier surface and said edge to drive said field-stiffened magnetorheological fluid through said converging gap such that a work zone is created by the moving magnetorheological fluid to form a transient finishing tool for engaging and causing material removal at said edge of said optical element.

2 more elements

An apparatus for finishing an edge of an optical element using magnetorheological fluid, comprising:

a) a carrier surface adapted to carry a flow of magnetorheological fluid;
b) an optical element holder for holding an optical element to position a portion of an edge of said optical element near said carrier surface to define a converging gap therebetween, and to position said element such as to exclude definition of a converging gap between image-forming refractive and reflective surfaces of said element and said carrier surface;
c) a magnet for applying a magnetic field at said gap;
d) means for introducing magnetorheological fluid to said carrier surface near said converging gap, said fluid becoming stiffened in said magnetic field;
e) means for moving one of said carrier surface and said element holder relative to the other in first relative motion such that said stiffened magnetorheological fluid on said carrier surface is driven through said gap to create a work zone in the magnetorheological fluid forming a transient finishing tool for engaging and causing material removal at said portion of said edge.

2 more elements

Dependencies are inferred from the claim text.

Magnetorheological finishing of edges of optical elements

Life of this patent

Magnetorheological finishing of edges of optical elements

Life of this patent

Abstract

Claims31