GB1308173A - Production of optical surfaces and elements - Google Patents

Abstract

1308173 Moulding optical surfaces OFFICE NATIONAL D'ETUDES ET DE RECHERCHES AEROSPATIALES 24 June 1970 [24 June 1969] 30659/70 Heading B5A Optical surfaces are made by moulding on to a support of approximately the required shape a layer of hardenable resin by means of a matrix having an optically accurate surface of the required shape, the resin layer being caused to adhere to the support. The matrix is produced by conventional optical techniques whereas the support surface is as geometrically simple as possible, e.g. plane, conical spherical, pyramidal, or cylindrical whilst approximating to the required shape and produced by milling, turning, casting, or die stamping. The matrix may be glass or aluminium alloy with a thick deposit of chemical nickel, the support of glass, silica or metal and the resin epoxy or cyanoacrylic. Dioptric elements such as lenses use a support body of glass and two optical surfaces are formed on it by the above process. In an example, the matrix is a zone of an optical cube adjacent one corner, i.e. tretrahedron 13, metallized under vacuum to give a reflective anti-adhesive coating. A support body 20 of aluminium alloy has a recess 21 approximating to the tetrahetron and a layer 22 of hardenable resin is brushed on to the three internal faces. The tetrahedron is placed in the recess 21 and a weight 27 added to ensure even distribution of the resin. There results an optically accurate reflector having three mutually perpendicular reflecting surfaces. If the optical element is to be refracting the anti-adhesive coating is removed from the resin layer by a suitable chemical agent.