Patent ID: 7160587

Claim:
A flat panel display element, comprising: an optically transparent display component which comprises a plastic substrate, the substrate comprising a fumaric acid diester resin which comprises 60 mol % or more of a fumaric acid diester residue unit represented by the following formula (1): wherein R 1 and R 2 each independently represent a branched alkyl group or a cyclic alkyl group, having 3–12 carbon atoms, said resin having a number average molecular weight of 1,000–500,000, as determined by a gel permeation chromatography and converted into standard polystyrene; wherein the substrate has a thickness of 30–600 μm, an unevenness in the thickness of 10 μm or less, a retardation of 10 nm or less, as measured from a front of the substrate, and an unevenness in the retardation of 5 nm or less within a plane of the substrate.