REDUCING POLYMERIZATION STRESS BY CONTROLLED SEGMENTAL CURING

摘要

A photopolymerizable material is exposed to light to effect curing. A portio n of the material is exposed to light in a conventional manner, while at least one other portion of the material is masked from direct exposure to the ligh t by use of a mask (10) having at least one mask segment (11) which either completely or at least partially blocks the light. In this manner, the polymerization stress associated with the cured materials is limited or minimized due to extended molecular relaxation promoted by this controlled o r hybrid curing technique. Also according to the invention, different segments (30, 31) of a material to be cured (22) are exposed to different wavelengths of light energy (21) or one such segment (30, 31) is exposed to light energy while another such segment is not.