Abstract: A method of manufacturing an optical disc includes molding a first disc substrate by a first mold simultaneously with a second disc substrate by a second mold while controlling the temperature of the first and second molds by passing a temperature-controlling medium through temperature controlling flow passages provided in the vicinity of a boundary between the first and second molds.

Abstract: A method of manufacturing an optical disc includes molding a first disc substrate by a first mold simultaneously with a second disc substrate by a second mold while controlling the temperature of the first and second molds by passing a temperature-controlling medium through temperature controlling flow passages provided in the vicinity of a boundary between the first and second molds.

Abstract: In an optical disc molding device, a heating medium from a low-temperature controller is made to flow in temperature controlling flow passages (passages 3a) formed at locations corresponding to boundary parts of two fixed molds 7 mounted parallel to each other on a fixed platen 3 and in temperature controlling flow passages (passages 6a) formed at locations corresponding to boundary parts of two movable molds 8 mounted parallel to each other on a movable platen 6 to supplement heat exchange.

Abstract: In an optical disc molding device, a heating medium from a low-temperature controller is made to flow in temperature controlling flow passages (passages 3a) formed at locations corresponding to boundary parts of two fixed molds 7 mounted parallel to each other on a fixed platen 3 and in temperature controlling flow passages (passages 6a) formed at locations corresponding to boundary parts of two movable molds 8 mounted parallel to each other on a movable platen 6 to supplement heat exchange.

Abstract: A plastic underdrainage tube of generally reticular configuration formed by integrally extruding a plastic material is disclosed. The tube is basically composed of axially spaced apart annular bands having relatively greater thicknesses to reinforce or impart to the tube a high stability against surrounding pressures, and circumferentially disposed longitudinal strands in thicknesses less than those of said annular bands. These longitudinal strands are closely spaced apart along the circumference of the tube to form drainage openings between the circumferentially adjacent strands, the openings being disposed across the entire periphery and lengthwise of the tube to allow the water inflow over the entire wall portion thereof.