Abstract: A multi-layer optical record blank and information record comprises a light-reflective layer, a light-transmissive layer, a light-absorptive layer, and a heat-sensitive information layer wherein the thicknesses of the layers are chosen to achieve a low-reflection condition. Information is recorded as variations of an optical property in the information layer indirectly heated by light absorbed in the absorptive layer.

Abstract: An optical recording medium comprises a light reflecting material which is coated with a light absorbing layer and overcoated with a 0.05-1 millimeter thick layer of an optically transparent and chemically and thermally stable material such as a silicone resin. During recording, portions of the light absorbing layer are ablated or melted by a modulated focussed light beam, thereby exposing portions of the reflecting layer while leaving the overcoat layer intact. Information is recorded in the form of a reflective-antireflective pattern. Dust particles and other surface contaminants settle on the upper surface of the overcoat layer, so far removed from the focal plane of the recording lens that their effect on the recording or playback signal is considerably reduced, and no defect is noticeable on the playback monitor.

Abstract: An ablative optical recording medium comprises a substrate coated with a light reflecting coating of passivated aluminum which in turn is coated with a light absorbing ablative layer. During recording, portions of the light absorbing layer are ablated, or vaporized, by a modulated focussed light beam, thereby exposing portions of the reflective layer. Information is recorded in the form of a reflective-antireflective pattern.

Abstract: An optical recording medium comprises a light reflecting material which is coated with a light absorbing layer and overcoated with a thin, amorphous, coherent layer of an optically transparent and chemically and thermally stable material such as silicon dioxide. During recording, portions of the light absorbing layer are ablated by a modulated focussed light beam, thereby exposing portions of the reflecting layer while leaving the overcoat layer intact. Information is recorded in the form of a reflective-antireflective pattern. Dust particles and other surface contaminants can be wiped or washed off the recording medium without damage to the light absorbing layer.

Abstract: A flat major surface of a disc-shaped substrate (e.g., glass or plastic) is coated with a light-reflective layer (e.g., aluminum) which is coated with a dielectric material (e.g., silicon dioxide) highly transparent for light of a frequency supplied by a recording laser. The dielectric material is coated with a thin layer of a smooth continuous, low melting point, low thermal diffusion length metal (e.g., tellurium) absorptive for light of the frequencies supplied by the recording laser. The coating parameters are chosen to establish an anti-reflective condition for the coated record blank at the recording light frequency. The light output of the laser, which is intensity modulated in accordance with a signal to be recorded, is focused upon the coated surface of the disc as the disc is rotated.

Abstract: An ablative recording medium comprises a substrate coated with a light reflecting layer which in turn is coated with a light absorptive layer of 6,6'-diethoxythioindigo. During recording, portions of the light absorptive layer are ablated by a modulated focussed light beam, thereby exposing portions of the reflecting layer. Video information is recorded as a reflective-antireflective pattern.

Abstract: An optical record blank structure comprises a disc-shaped substrate (e.g., glass), a layer of light-reflective material (e.g., aluminum) overlying a surface of the disc-shaped substrate, a coating of a transparent material (e.g., silicon dioxide) overlying the light-reflective layer and a coating of a moderately absorptive material (e.g., an organic dye such as fluorescein) overlying the dielectric coating. The coating parameters are chosen to establish an antireflective condition to a recording light beam incident on the disc surface. The transparent coating thickness is selected such that the transparent coating is optically passive to the recording light beam, i.e., the thickness of the transparent coating is selected to be an integer multiple of the half-wavelength of the recording light beam wavelength in the transparent material.

Abstract: A flat major surface of a disc-shaped substrate (e.g., of glass) is coated with a light-reflective layer (e.g., of aluminum) which is coated with a dielectric material (e.g., silicon dioxide) highly transparent for light of a frequency supplied by a recording laser and of a thickness equal to an integer multiple of the half-wavelength of the laser light output in the dielectric material. The dielectric material is coated with a layer of material moderately absorptive for light of the frequency supplied by the recording laser (e.g., an organic dye such as fluorescein). The coating parameters are chosen to establish an anti-reflection condition for the coated record blank at the recording light frequency. The light output of the laser, which is intensity modulated in accordance with a signal to be recorded, is focused upon the coated surface of the disc as the disc is rotated.

Abstract: Playback apparatus, providing a playback beam of light, effects signal recovery, from an information record, with a high signal-to-noise ratio. An information record, suitable for use with such playback apparatus, comprises a flat major surface of a disc-shaped foundation coated with a layer of a thermally conductive material overlaid with a layer of a thermally insulating material. Information storage is effected in a layer of material (e.g., platinum-cobalt), highly absorptive for light of a frequency supplied by a recording laser, which layer overlies the insulating layer. By proper choice of thicknesses for the insulating and the conductive layers, absorptive layer sensitivity to the intensity of the playback beam of lights is effectively reduced to enable record playback at high playback beam intensity levels without damage thereto. Where the foundation is formed of a thermally conductive material, the layer of thermally conductive material may be dispensed with.