Patent ID: 6671095
Filing Date: 2003-12-30
Classification: B29C,B29D,B33Y,G02B,G03H,Y10T

Abstract:
A method of preparing a composite micro relief element which comprises(a) a first layer of a first substrate having a first refractive index, the first layer having a receptive surface; and (b) a second layer of a relief forming polymer having a second refractive index which is retained on the receptive surface of the first layer, wherein the second layer comprises overlay and at least one relief feature portions; wherein the overlay portion is affixed to the receptive surface, serves to planarise the receptive surface, and has a thickness variation less than +/âˆ’0.75 micron; (c) and wherein the at least one relief feature portion protrudes above the overlay portion which method comprises (1) forming a line of contact between the receptive surface and at least one mould feature formed in a flexible dispensing layer; (2) applying a sufficient quantity of a resin, capable of being cured to form the relief forming polymer, to substantially fill the at least one mould feature, along the line of contact; (3) progressively contacting and applying pressure between the receptive surface and the flexible dispensing layer along the line of contact such that (a) the line of contact moves across the receptive surface; (b) sufficient of the resin is captured by the mould feature so as to substantially fill the mould feature; and (c) no more than a quantity of resin capable of forming the overlay portion passes the line of contact; (d) curing the resin filling the at least one mould feature before the pressure applied along the line of contact is released and before the resin relaxes from the mould feature so as to form the at least one relief feature portion; and, optionally, thereafter (e) releasing the flexible dispensing layer from the at least one relief feature portion.