Sn. Kang et al., Birefringence distribution in magneto-optical disk substrate fabricated byinjection compression molding, OPT ENG, 39(3), 2000, pp. 689-694
It is necessary to improve optical and mechanical properties in optical dis
k substrates as information storage devices with high storage density using
short-wavelength lasers are being developed. Injection compression molding
is regarded as the most suitable process to manufacture optical disk subst
rates with high dimensional accuracy, low residual stress, and superb optic
al properties. Polycarbonate magnetooptical disk substrates are fabricated
by injection compression molding, and the birefringence, regarded as one of
the most important optical properties for optical disk, is measured. The e
ffects of various processing conditions on the development of birefringence
distribution are examined experimentally. It is found that the values of t
he birefringence distribution are very sensitive to the mold wall temperatu
re history. By controlling the compression process, the overall birefringen
ce value can be reduced. (C) 2000 society of Photo-Optical instrumentation
Engineers. [S0091-3286(00)00703-0].