GB1163002A - Light transmitting element. - Google Patents

Abstract

1,163,002. Laminated light-transmitting element; moulding optical elements. KIRK OPTICAL LENS CO. Inc. 31 Aug., 1966 [6 May, 1966], No. 38788/66. Headings B5A and B5N. [Also in Divisions C1 and G2] A light-transmitting element comprises a body of rigid and infusible thermosetting material having chemically bonded to its outer surface at least one relatively thinner layer of glass or plastics material which is more abrasion resistant than is the thermosetting material. The thermosetting material may be an epoxy resin; a polysulphide/epoxide copolymer; an unsaturated polyester; a polyurethane; an unfilled silicone; or a ureaformaldehyde resin. When plastics is used as an outer layer it may be an allyl resin, e.g. allyl diglycol carbonate resin. In one method of making an element, e.g. an ophthalmic lens outer glass layers 14, 16, Fig. 3 are spaced by a gasket 18 to form a chamber into which liquid thermosetting material 12 is poured. Heat is then applied to cure the resin after which the gasket 18 is removed and the edges of the lens trimmed. The thermosetting material or the outer layers may be coloured. In a second embodiment, a thin layer of cellulose acetate, which may be tinted to act as a filter, is placed between the outer layers of the lens before pouring in the thermosetting material. In a further method, used to produce a varifocal lens, one outer layer 52 and a former 64 coated with release material are arranged as shown in Fig. 11c to form a chamber into which a thermosetting material 58 is poured, this material then being cured by heat. The former is then removed and a second thermosetting material of different refractive index is poured between the material 58 and the second outer layer 54 and cured. In another embodiment in which a multifocal lens is produced, the outer layers are arranged to form a chamber and a metal insert is placed between the layers before a thermosetting material is poured therebetween. After curing of this material the metal insert is removed and the space resulting filled with a thermosetting material of a different refractive index. The elements may be formed as lenses, is described above, as flat members, for use as windows, shelving or desk tops, or as curved members for use as windscreens, instrument dials or protective shields. They have high thermal stability and are thermally insulating. The thermosetting material may include a wire mesh. In another embodiment, Fig. 7, outer layers 40, 42 of glass, to which a layer of thermosetting material 38 has been secured by employing each of the outer layers separately as one wall of a mould chamber, pouring in the material 38 and curing it, are used together as the walls of a mould into which a material 36 which does not ahere to glass, e.g. a polysiloxane, is poured and then cured.