Method of manufacturing an optical reading disc

Claim 1

A method of making an optical recording disc, comprising the steps of: molding two thin, disc-shaped members, each having an inner integral ring-shaped boss located at the center of the member and an outer integral ring-shaped boss concentric with said inner boss and located at the outer periphery of said member and projecting upwardly from a confronting side thereof and forming a shallow, annular recess therebetween wherein the inner and outer bosses of each member both have uniform thicknesses and planar upper surfaces parallel to the plane of the member, and wherein the two members are substantially identical in shape and at least one of the two members is transparent; said step of molding including a step of forming a circular hole in the center of each of the two disc-shaped members, concentric with its inner and outer bosses; coating the annular recess portion of one of the two disc-shaped members with a thin recording layer of light-sensitive material; and bonding together the pair of disc-shaped members in a coaxial relationship, with their respective inner and outer bosses in abutment with each other, thereby producing the optical recording disc.

Claim 2

A method of making an optical recording disc, comprising the steps of: molding two thin, disc-shaped members, each having an inner integral ring-shaped boss located at the center of the member and an outer integral ring-shaped boss concentric with said inner boss and located at the outer periphery of said member and projecting upwardly from a confronting side thereof and forming a shallow, annular recess therebetween wherein the inner and outer bosses of each member both have uniform thicknesses and planar upper surfaces parallel to the plane of the member, and wherein the two members are substantially identical in shape and at least one of the two members is transparent; said step of molding including a step of forming a circular hole in the center of each of the two disc-shaped members, concentric with its inner and outer bosses; coating the annular recess portion of one of the two disc-shaped members with a thin recording layer of light-sensitive material; and bonding together the pair of disc-shaped members in a coaxial relationship, with their respective inner and outer bosses in abutment with each other, thereby producing the optical recording disc.

Claim 6

A method of making an optical recording disc, comprising the steps of: molding two thin, disc-shaped members, each having an inner, integral ring-shaped boss located at the center of the member and an outer, integral ring-shaped boss concentric with said inner boss and located at the outer periphery of said member and projecting upwardly from a confronting side thereof and forming a shallow, annular recess therebetween, wherein the inner and outer bosses of each member both have uniform thicknesses and planar upper surfaces parallel to the plane of the member, and wherein the two members are transparent and substantially indentical in shape; said step of molding includes a step of forming a circular hole in the center of each of the two disc-shaped members, concentric with its inner and outer bosses, to facilitate use of the optical recording disc with recording apparatus; vacuum depositing a thin recording layer of light-sensitive material onto the annular recess portions of each of the two disc-shaped members, said recording layers both having a substantially uniform thickness; and solvent bonding together the pair of disc-shaped members in a coaxial relationship, with their respective inner and outer bosses in abutment with each other, thereby producing an optical recording disc in which information can be recorded in each of the two recording layers by directing an intensity-modulated beam of light onto the layer, through the underlying, transparent disc-shaped member.

Claim 7

A method of making an optical recording disc, comprising the steps of: molding two thin, disc-shaped members, each having an inner, integral ring-shaped boss located at the center of the member and an outer, integral ring-shaped boss concentric with said inner boss and located at the outer periphery of said member and projecting upwardly from a confronting side thereof and forming a shallow, annular recess therebetween, wherein the inner and outer bosses of each member both have uniform thicknesses and planar upper surfaces parallel to the plane of the member, and wherein the two members are transparent and substantially indentical in shape; said step of molding includes a step of forming a circular hole in the center of each of the two disc-shaped members, concentric with its inner and outer bosses, to facilitate use of the optical recording disc with recording apparatus; vacuum depositing a thin recording layer of light-sensitive material onto the annular recess portions of each of the two disc-shaped members, said recording layers both having a substantially uniform thickness; and solvent bonding together the pair of disc-shaped members in a coaxial relationship, with their respective inner and outer bosses in abutment with each other, thereby producing an optical recording disc in which information can be recorded in each of the two recording layers by directing an intensity-modulated beam of light onto the layer, through the underlying, transparent disc-shaped member.