Patent ID: 6828007
Filing Date: 2004-12-07
Classification: G02B,Y10T

Abstract:
A flat plate made of a cycloolefin polymer comprising at least 30% by weight, based on the cycloolefin polymer, of repeating units (A) having an alicyclic structure; said repeating units (A) comprising at least 30% by weight, based on the repeating units (A), of the repeating units (A-i) having no norbornane structure and more than 0% hut not more than 70% by weight of repeating units (A-ii) having a norbornane structure, represented by the following formula (4): wherein R35 through R48 are independently selected from the group consisting of a hydrogen atom, an alkyl or alkenyl hydrocarbon, hydroxyl, ester, alkoxy, cyano, imido and silyl groups, a halogen atom, and alkyl or alkenyl hydrocarbon groups having a functional group as a substituent selected from the group consisting of hydroxyl, ester, alkoxy, cyano, imido and silyl groups; R38 and R39, or R40 and R41 may form together an alkylidene group having 1 to 20 carbon atoms; e is an integer of 1 to 3; and  represents a carbon-carbon single or double bond; and said cycloolefin polymer having a weight average molecular weight of 5,000 to 50,000, wherein an illuminating surface of the flat plate has a surface roughness of not larger than 5 &mgr;m as expressed in terms of maximum height (Rmax).