Table 1.

The optical properties of the CPIs.

PI Film Code	λ0 a (nm)	T400 b (%)	T550 b (%)	b*	YI	n c	∆nth d	Retardationth e /(nm)
PI-0	345	80	91	1.07	2.04	1.540	0.0276	276
PI-1	343	71	91	1.58	2.83	1.571	0.0347	347
PI-2	358	52	90	2.13	3.75	1.577	0.0397	397
PI-3	372	30	90	2.84	4.90	1.579	0.0458	458
PI-4	371	31	90	3.37	5.78	1.586	0.0468	468
PI-5	376	21	89	4.93	8.63	1.580	0.0496	496

^a cutoff wavelength of UV–vis; ^b transmittance at 400 nm and 550 nm; ^c refractive indices at 550 nm; ^d out-of-plane birefringence at 550 nm; ^e retardation per 10 μm of PI films at 550 nm.