Polyimide und durch deren Verwendung erhältliche optische Bauteile

摘要

Polyimides satisfying the requirements (a), (b) and (c) among the requirements described below, polyimides satisfying the requirements (b), (c) and (d), and polyimides satisfying the requirements (a), (b), (c) and (d) are excellent in transparency, isotropy and resistance to cracking (no crack is formed in the formation of a multilayer film, so that the multilayer formation is easy, namely, the polyimides are good in processability) and can give optical parts excellent in optical characteristics: (a) the difference between the refractive index in TE mode and that in TM mode is 0.02 or less, (b) the glass transition temperature (Tg) is 250 DEG C or higher, (c) the optical transmission loss at a wavelength of 0.7 to 1.6 mu m is 1 dB/cm or less, and (d) the fluorine content is 22.6% by weight or less.