Abstract: A magneto-optical disk having a four-layer structure formed of a first protective dielectric layer, a recording magnetic layer, a second protective dielectric layer and a reflective metal layer is disclosed. The constraints for the film thicknesses of the various layers are determined not only from the optical and magneto-optical aspects, but from the aspect of the dynamic thermal response.The recording magnetic layer is a magnetic layer mainly formed of TbFeCo and having a film thickness of not less than 180 .ANG. and not more than 280 .ANG.. The first protective dielectric layer is a nitride film having a film thickness such that the product of its refractive index and the film thickness is not less than 0.2 and not more than 0.35 times the wavelength of the laser light employed. The second protective dielectric layer is a nitride film having a film thickness such that the product of its refractive index and the film thickness is not less than 0.1 and not more than 0.

Abstract: An image display apparatus having light beam sources for generating light beams, an optical modulator for modulating the light beams by image signals to be projected, a deflection device for deflecting the modulated light beams, the deflection device including a polygon mirror and an auxiliary reflection mirror provided near the polygon mirror such that the modulated light beams are reflected from the polygon mirror to said auxiliary reflection means and back toward the polygon mirror, a device for supplying the modulated light beams to the polygon mirror with predetermined angles relative to a rotational plane of the polygon mirror, such that the modulated light beams incident upon the polygon miror are reflected a plurality of times by the polygon mirror, and a projection device for projecting the modulated and deflected light beams from the deflection device on a screen or the like.

Abstract: A display apparatus having a screen, a light beam source for generating light beams, an optical modulator for modulating the light beams in accordance with image signals to be displayed, a scanning apparatus for generating scanning beams of the modulated light beams, a projection apparatus for projecting the scanning beams on the screen, a reference beam source for generating a reference beam to be supplied to the scanning apparatus, a circuit for deriving a scanning reference beam, a circuit for generating timing signals based on the derived scanning reference beams, and a circuit for controlling timings of the image signals to be supplied to the optical modulator.

Abstract: This invention relates to a laser scanning apparatus which raster-scans a laser beam by using an acousto-optic deflector. In this laser scanning apparatus, the laser beam is horizontally scanned by a pair of acousto-optic deflectors. Thus, a laser scanning apparatus can be realized, which is low in noise, excellent in durability, small in size, light in weight and which can display a picture of high quality at high speed.

Abstract: A laser beam deflection apparatus is comprised of a polygon mirror having a plurality of reflection surfaces, a laser beam incident on the reflection surfaces of the polygon mirror, and n number of reflection devices positioned in facing relation to the polygon mirror, and aligned in a rotational direction of the polygon mirror for reflecting the laser beam reflected from one of the reflection surfaces back towards the one of the reflection surfaces of the polygon mirror, whereby the laser beam is twice reflected by the one of the reflection surfaces and is deflected through a predetermined angle n times during each predetermined increment of rotation of the plurality of reflection surfaces of the polygon mirror.

Abstract: An optical recording disc in which a disc substrate made of a synthetic resin having a light transmittance and a hub made of a synthetic resin, fixed to a center part of the disc substrate by means of a predetermined technique such as a supersonic wave expansion molding and on which a circular magnetic metal plate is installed by means of an insert molding and so on are provided and a circular groove which is continuous at an outer peripheral side of a fixing part between the disc substrate and hub is furthermore installed on at least either of the disc substrate or hub. The groove is provided for absorbing a stress generated due to a difference in thermal expansion rates between the disc substrate made of the snythetic resin and magnetic metal plate.

Abstract: An information recording medium for use with focused laser beams modulated with recorded information signals comprising a substrate having a recording layer composed of at least two layers, the first being formed on the substrate and the second being formed over the first. The substrate and the first layer have the property of high transmittance to laser beams and the second layer is composed of a metal which is predominantly a low melting metal capable of absorbing the laser beams and readily forming an alloy with the material of the first layer, the thickness of the first layer being such that the reflectance of the laser beams entering from the side of the substrate is lowered by the interference effect caused by repetitive multiple reflections.

Abstract: An information recording medium which includes a light-transmitting substrate, a recording layer formed on the substrate, the recording layer having the characteristic of changing an optical characteristic upon heating thereof, together with a protective layer having light-absorbing properties disposed over the recording layer and arranged to absorb light passing through the recording layer upon recording, in combination with a planar layer superimposed on the protective layer and capable of suppressing mechanical deformation of the recording layer.