申请人:HITACHI CHEMICAL COMPANY, LTD.
公开号:EP0758665A1
公开(公告)日:1997-02-19
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°C or higher,
(c) the optical transmission loss at a wavelength of 0.7 to 1.6 µm is 1 dB/cm or less, and
(d) the fluorine content is 22.6% by weight or less.
满足下述要求中(a)、(b)和(c)项的聚酰亚胺,满足(b)、(c)和(d)项的聚酰亚胺,以及满足(a)、(b)、(c)和(d)项的聚酰亚胺,在透明度、各向同性和抗裂性(在形成多层膜时不会产生裂缝,因此多层膜的形成容易,即聚酰亚胺的加工性好)方面都非常出色,可以生产出光学特性出色的光学部件:
(a) TE 模式下的折射率与 TM 模式下的折射率之差为 0.02 或更小、
(b) 玻璃转化温度(Tg)为 250°C 或更高、
(c) 波长为 0.7 至 1.6 微米时的光传输损耗为 1 dB/cm 或以下,以及
(d) 氟含量为 22.6%(重量百分比)或更低。