PROCESS FOR MAKING AN ARRAY OF TAPERED PHOTOPOLYMERIZED WAVEGUIDES

摘要

The present invention is directed to a process for making an array of tapere d photopolymerized waveguides. The tapered waveguides are useful as a display means in direct view devices and projection display devices. In step (a), a photomask is placed in substanti al contact with a substrate wherein the photomask has opaque and transparent re gions. In step (b), a substantially uniform thickness of photpolymerizable mixture is placed on the substrate so that the substrate i s positioned between the photopolymerizable mixture and the photomask wherein (i) the photopolymerizable mixture comprises at least one reactive monomer and photoinitiator and (ii) the photoin itiator is present in an an amount sufficent to form a gradient of substantially col limated actinic radiation across the thickness of the ph otopolymerizable mixture during subsequent step (c). In step (c), while maintaining the photo polymerizable mixture and substrate in a substantially f ixed plane relative to the substantially collimated actinic radiation, the photop olymerizable mixture is exposed through the transparent regions of the photomask to the substantially collimated actinic radiation for a time s ufficent to form an array of tapered photopolymerizable waveguides wherein (i) the tapered end of each of the waveguides extends outward from t he substrate, (ii) each of the waveguides has a light in put surface adjacent the substrate and a light output surface distal from the li ght input surface, and (iii) the area of the light input surface of each of the waveguides is greater than the area of its light output surface. In step (d), the photomask and photopolymerizable mixtu re which was not substantially polymerized by the substantially collimated actinic ra diation during step (c) are removed from the substrate.