| 摘要 |
<p>A light transmissive glass substrate (2) having a profile (3) which matches in part a desired aspherical profile (4) and having thereon a thin coating of a light transmissive polymeric material which has a minimum thickness (5,5 min and 5 sec , 5''') at the matching aspherical part of the glass profile and which increases uniformly in thickness to a maximum, to give a differential thickness which is just sufficient to accommodate the difference between the remainder of the profile of the substrate and the desired profile whereby the glass substrate (2) is first prepared to a second order of profile accuracy when compared with the desired profile by quantity production techniques, such as, casting, machining or grinding, the substrate is then supported in a mould tool in close proximity to an optically polished surface of a negative profile of the desired aspherical profile and the region between the facing surfaces of the glass substrate and mould filled with the light transmissive polymeric material.</p> |
