Manufacturing method of plastic lens and the lens

A method of manufacturing a plastic lens in which a rotatable disc is provided and a plurality of cylinders which allow molds to pass therethrough are provided along an inner circumference of the rotatable disc, a piston shaft which includes a mold holding portion being arranged on a center axis of the cylinder, the molds having a planned combination, the method comprising:

• placing two respective ones of the molds which have the planned combination on a transport base;
• heating the two molds in a state that a one of the two molds having a convex forming surface is heated with the forming surface directed upwardly and the mold having a concave forming surface is heated with the forming surface directed downwardly;
• holding one of the two molds in the inside of the cylinder;
• controlling the piston shaft using at least one pre-controlled automatic transport device and/or manually such that the forming surface of said one of the two molds having the convex forming surface assumes substantially a same height as an upper surface of an opening portion of the cylinder or slightly projects from the upper surface of the opening portion thus arranging the mold in a fixed manner;
• causing an optical thermoplastic resin molten material having no agitation flow or having a negligible agitation flow to flow out from a nozzle of an extruding machine so as to be placed on the one of the two molds, the resin molten material which flows out from the nozzle of the extruding machine along with the rotation of the disc being placed in a direction of the rotation over an area ranging from a one-side end portion to another-side end portion with respect to the center of the convex forming surface;
• subsequently placing an other of the two molds having the concave forming surface on the resin molten material with the forming surface directed downwardly;
• and
• urging both of said two molds towards one another in the inside of the cylinder until a given distance is defined so as to form a plastic lens by pressing the resin molten material,
• wherein, the automatic transport device comprises:
• an inclined transport base which transports the molds in the tangential direction of a circle which the center of the rotating cylinder opening portion draws;
• and
• an extruding member which extrudes the molten material at a speed in synchronism with a circumferential speed of the cylinder opening portion is mounted on the transport base, and the mold is moved in the center direction of the cylinder.

A method of manufacturing a plastic lens, comprising:

• imparting a fixed speed of rotation to a rotatable disc about a rotation axis, said rotatable disc including cylindrical passages being disposed peripherally of said disc along an inner circumference thereof, said cylindrical passages extending coaxially with said rotation axis;
• providing respective pairs of molds, each of said pairs of molds comprising a lower mold and an upper mold, said lower mold and said upper mold defining a predetermined combination in which said lower mold presents a convex forming surface and said upper mold includes a concave forming surface;
• placing said pairs of molds on a transport platform such that each said lower mold is oriented with the convex forming surface directed upwardly and the upper mold is oriented with the concave forming surface directed downwardly;
• heating said pairs of molds on said transport platform;
• arranging a lower piston shaft which includes a mold holding portion movable vertically within each of said cylindrical passages along a center axis of each of said cylindrical passages;
• transferring a one said lower mold from said transport platform to said mold holding portion corresponding to a respective one of said cylindrical passages;
• controlling a vertical position of the piston shaft such that the convex forming surface of said lower mold assumes substantially a same height as an upper surface of an opening portion of the corresponding one of said cylindrical passages or slightly projects from the upper surface of the opening portion so as to support the lower mold in a fixed manner;
• causing an optical thermoplastic resin molten material having no agitation flow or having a negligible agitation flow to flow out from a nozzle of an extruding machine as an extruded band of said optical thermoplastic resin molten material deposited, along with the rotation of the disc in a direction of the rotation, across the convex forming surface and extending at least into a region of a top surface of the rotatable disc which is disposed between said corresponding one of said cylindrical passages and an adjacent one of said cylindrical passages;
• subsequently transferring a one said upper mold from said transport platform onto the resin molten material with the concave forming surface directed downwardly;
• and
• urging said upper mold and said lower mold said towards one another in an inside of the corresponding one of said cylindrical passages until a given distance is defined therebetween so as to form a plastic lens by pressing the resin molten material.