Fine patterning, pregrooved layer coatings, on glass disks by the sol-gel method has been successfully achieved. The pregrooving process, formation of a sol-gel film on a glass substrate, stamping the groove pattern on the gel film and heat treatment, is described. The specifications of the pregrooved glass disk of 130 mm in diameter are satisfactory for the requirements as an optical disk substrate in terms of dimensional and physical characteristics, mechanical characteristics, signals from grooves. It is noted that the sol-gel pregrooved optical disks substrates have such excellent features as small dynamic radial runout, very small tilt and much long life comparing with those of conventional plastic disk substrates. Cost- performance characteristics are discussed for suitable applications of the sol-gel pregrooved optical memory disks.
"Sol-gel technology for optical disk application", Proc. SPIE 1758, Sol-Gel Optics II, (7 December 1992); doi: 10.1117/12.132005; https://doi.org/10.1117/12.132005