Experimental Study on Spin Coated Thin Cover Layer for High Numerical Aperture Optical Disc

The present study relates to a method of manufacturing 100<TEX>$mu extrm{m}$</TEX> thick cover layer for the high density digital versatile disc system (HD-DVD), which uses a high numerical aperture of 0.85 at 405 nm wavelength. Spin coating technique was investigated as means for manufacturing the cover layer within sufficient margins of thickness variation and with good mechanical properties including small radial and tangential tilts. The influence of processing variables such as spinning speed, spinning time, and dispensing position was investigated. The effect of viscosity of UV-curable resin was also investigated.