Abstract: A relatively thick metal oxide film of 100 nm or more is formed in the exposed portion of a resist film by supplying water and a metal alkoxide thereto, and then evaporating the alcohol generated by the supply of metal alkoxide to form a precise resist pattern from the metal oxide film. Water is absorbed into the exposed portion of the resist film in which the acid has been generated and the water is diffused deeper into the surface thereof. The growth of the metal oxide film proceeds toward the interior of the resist film. The water absorbed by the resist film is prevented from being evaporated, thereby forming a metal oxide film with a sufficiently large thickness to withstand dry etching.

Abstract: An operation circuit for performing either fixed or floating point mathematical operations, having a mode control function for a multiplier including a multiplier, an arithmetic logic unit (ALU) and a signal generating circuit. A signal specifying the operating mode of the ALU, either a fixed point mode or a floating point mode is used by the signal generating circuit for generating either a fixed point multiplication signal or a floating point multiplication signal to control the multiplier, respectively.

Abstract: An erasable optical disk having a grooved substrate which is made of a cured polymer product formed by radical polymerization of a composition comprising a specific type of (meth)acrylate compound alone or in combination with at least one compound selected from N-substituted maleimide compounds and epoxy-novolac (meth)acrylate compounds. The substrate has a good heat resistance, a good transparency, and can be produced at a high productivity.

Abstract: A transparent plastic article with less internal strain is produced by successively polymerizing a monomer part by part with forming a gel state part between the already polymerized part and the unpolymerized part, or by polymerizing a monomer by means of a mold which can follow cure shrinkage of the monomer in order to decrease cure shrinkage. The article produced is particularly suitable for optical applications such as an optical disc, a lens and a prism.

Abstract: A method for producing a plastic substrate having Tg of 110.degree. C. or more is disclosed, which comprises radical polymerizing a polyfunctional (meth)acrylate compound in a mold by a cast molding method, removing the resulting substrate from the mold when the glass transition temperature of the substrate reaches 10.degree. to 100.degree. C., and then post-curing the substrate. The method of the present invention can provide high quality plastic substrates with high productivity.

Abstract: A method for the formation of a light-shield coat on a peripheral area of an optical lens other than the effective aperture area, which method is constituted by the steps of mounting the lens on a rotatable lens support means effective to rotate the lens about the optical axis thereof with the peripheral area positioned exteriorly of the lens support means, applying to the peripheral area of the lens a photo-setting, black-colored light shielding paint capable of hardening when exposed to ultraviolet rays to form the light-shield coat on the peripheral area of the lens, and radiating ultraviolet rays onto the peripheral area of the lens, while the latter is rotated, to cause the light-shield coat to harden.