Abstract: The combination of recordable-reproduceable optical discs and reproducing-only optical discs and an optical disc player which is capable of reproducing recorded signals both from the recordable-reproduceable optical disc possessing pregrooves and the reproducing-only optical disc possessing recording pits by means of a common optical system. The common optical system has a common laser for irradiating both types of discs with a laser beam used for reading the discs. The wavelength of the laser is .lambda. and the depth or height of the pregrooves of the recordable-reproduceable optical disc is made equal to or less than .lambda./8n, and the depth or height of the recording pits of the reproducing-only optical disc is made equal to or greater than .lambda./8n but less than .lambda./4n, wherein n is the refractive index of the substrate of the disc or the protective layer provided on the surface thereof.

Abstract: A device for producing information recording disks comprises a stamper mount for placing a stamper thereon, a stamper-fixing shaft for fixing the stamper, and a pressing plate for pressing a backing plate toward the stamper after a liquid resin is injected in the space between the backing plate and the stamper. Injection is effected via a passage made at the center of the stamper mount, and the injected resin is stretched outwardly radially by pressing the backing plate. An ultraviolet ray is irradiated to the stretched resin through the backing plate to harden the resin. An injection valve movably received in the stamper-fixing shaft may be used so that uninjected resin is prevented from being hardened. The injection valve may have a center projection as well as a flange portion at its top so that machining for making a center hole of the disk is unnecessary. The periphery of the flange portion may be wetted by the resin before the backing plate is placed on the flange portion.

Abstract: Provided is an information recording medium manufacturing device of the type in which a radiation curable layer-forming liquid resin is injected into a gap between a planar stamper carrying an information recording signal pattern to be transcribed and a planar flexible carrier member having at least one signal pattern carrying surface through means, for injecting the liquid resin, then the liquid resin is uniformly developed all over the surface of the carrier member by pressing a holding plate against the carrier member, and is set by irradiating radiant rays so as to form a transfer layer, thereby to obtain an information recording medium by separating from the stamper the carrier member united with the transfer layer.

Abstract: An optical recording system for holographically recording one-dimensional information varying with time such as audio signals.

Abstract: A light beam deflection system for producing diffracted light having a holographic light beam deflection disc bearing a record of unidimensional fringe patterns along the radial axis on a time division basis over a circumferential portion of the disc, and having means for focusing coherent light beams on the circumferential portion of the light beam deflection disc while rotating the disc.