Abstract: A method of manufacturing thermoplastic resin molded optical members comprising a thermoplastic resin material into a mold, defoaming thermoplastic resin material in vacuo at a specific temperature for causing the loaded thermoplastic resin material to melt and to flow, and producing a molded optical member by gradually cooling off the mold in the upward direction from the bottom side while pressurizing the interior of the mold with an inert gas. The inner surface of the mold is preferably preliminarily coated with a release material such as fluoroplastic containing either fluorinated alicyclic group or a fluorinated heterocyclic group in the main chain.

Abstract: A composite magnetic and optical head comprises a magnetic sensor including a magnetic core which is adapted to detect a magnetic pattern recorded on a record medium; an optical sensor including a nonmagnetic light transmitting member located along a distal gap of the magnetic sensor and an optical fiber bundle having one end connected to the light transmitting member, and adapted to detect an optical pattern recorded on the record medium; and a holder containing the magnetic and optical sensors in the internal space thereof, the holder having two opposite side walls extending at right angles to the distal gap of the magnetic core and one end face from which the distal gap projects outward.