Method and apparatus for producing cast synthetic resin structures by photopolymerization of monomeric material

Claim 1

AN APPARATUS FOR USE IN THE CASTING OF SYNTHETIC RESINOUS OPTICAL ELEMENTS WHICH CONSTITUTE A SOLID OF REVOLUTION WHICH COMPRISES IN COMBINATION A SOURCE OF LIGHT, A MOULD HAVING INTERNAL CASTING SURFACES DEFINING THE DESIRED SOLID OF REVOLUTION, SAID MOULD HAVING A CASTING SURFACE WHICH IS TRANSPARENT TO THE LIGHT ADMITTED FROM SAID LIGHT SOURCE, A SCREEN INTERPOSED BETWEEN SAID LIGHT SOURCE AND SAID LIGHT TRANSPARENT CASTING SURFACE, SAID SCREEN COMPRISING A SUBSTANTIALLY OPAQUE DISK HAVING AT LEAST ONE LIGHT TRANSMITTING SECTOR HAVIN A CONTOUR IN ACCORDANCE WITH THE INEQUALITY 0$0$KTX(1-BX), IN WHICH, USING CONVENTIONAL POLAR COORDINATES AND TAKING THE CENTER OF THE DISK AS THE ORIGIN WITH ANY RADIUS AS THE INITIAL LINE, K IS AN ARBITRARY CONSTANT SUCH THAT THE VALUE OF 0 IS, AT ALL VALUES OF X AND T, LESS THAN 360*, X IS ANY POINT UPON THE DISK, B IS ANY POSITIVE VALUE GREATER THAN ZERO AND LESS THAN 1/R, WHERE R IS THE RADIUS OF THE DISK AND TX IS THE THICKNESS OF THE LIQUID COMPOSITION UNDERGOING POLYMERIZATION MEASURED PARALLEL TO THE AXIS OF REVOLUTION OF SAID SOLID OF REVOLUTION, THE CENTER OF THE DISK BEING AXIALLY ALIGHED WITH SAID CENTER OF REVOLUTION, AND MEANS FOR CAUSING CONTINUOUS RELATIVE ROTARY MOVEMENT BETWEEN THE MOULD AND THE SCREEN ABOUT THEIR COMMON AXIS.