| 摘要 |
PROBLEM TO BE SOLVED: To provide a polyimide excellent in transparency, an isotropic property and crack resistance (without cracks on forming multilayers, easy for forming the multilayers and having a good processing property) and an optical part excellent in optical properties. SOLUTION: This polyimide having (a) <=0.02 difference between the refractive indexes of a TE mode and TM mode, (b) >=250 deg.C glass transition temperature (Tg) and (c) <=1 DB/cm light transmittance loss in 0.7-1.6μm wave length, the polyimide having (b) >=250 deg.C glass transition temperature (Tg), (c) <=1 DB/cm light transmittance loss in 0.7-1.6μm wave length and (d) <=22.6 wt.% fluorine content, or the polyimide having (a) <=0.02 difference between the refractive indexes of the TE mode and TM mode, (b) >=250 deg.C glass transition temperature (Tg), (c) <=1 DB/cm light transmittance loss in 0.7-1.6μm wave length and (d) <=22.6 wt.% fluorine content, and the optical part by using at least one of the polyimides are provided. |
