Synthesis and photopolymerization of oxetanes derived from bisphenol A

\u3cp\u3eA series of new dioxetanes derived from bisphenol A has been synthesized. Polymers were obtained by photopolymerization. The polymerization shrinkage of these relatively fast polymerizing dioxetane monomers was <3%, much less than that of dimethacrylates of a comparable molecular weight. The rates of polymerization compare favorably with that of the diglycidylether of bisphenol A, which also exhibits a low shrinkage. The relationship between the chemical structure and the temperature of maximum mechanical loss was investigated. Some of the new polymers exhibit temperatures of maximum mechanical loss sufficiently high to be useful for precision optical components made by photoreplication.\u3c/p\u3

A collimator for use in a backlight liquid crystal display system

\u3cp\u3eThe present invention relates to a system for lighting a display. The system comprises a light source (102), a collimator (120), and a liquid crystal display configured to receive a collimated light beam (126) and adapted to modulate the collimated light beam (126). The system further comprises a reflective sheet (110) having one or more pin holes (112) therein and having a reflective surface (116) facing the light source (102) and the other surface facing the collimator (120). The reflective sheet (110) is configured to transmit a part (114) of a light beam (108) to the collimator (120) and configured to reflect to a reflector (106) other parts (118) of the light beam (108).\u3c/p\u3