Abstract: To provide an optical information storage medium with high recording/reproducing sensitivity. An optical information storage medium 100 includes a substrate 56 and a multilayer structure 49, which is provided on the substrate 56 and includes at least one storage layer 57. The storage layer 57 includes polydiacetylene or merocyanine and is amorphous.

Abstract: A diffractive optical element emits substantially zero order diffracted light when light with a wavelength of 0.35 ?m to 0.45 ?m is incident and emits substantially first-order diffracted light when light with a wavelength of 0.6 ?m to 0.7 ?m is incident. The diffractive optical element includes a substrate and a grating portion formed on the substrate. The grating portion has a step-wise cross section with any one of levels selected from four levels, five levels and six levels. The diffractive optical element emits substantially zero-order diffracted light when light with a first wavelength ?1 satisfying the relationship: 0.35 ?m??1?0.45 ?m is incident and emits substantially first-order diffracted light when light with a second wavelength ?2 satisfying the relationship: 0.6 ?m??2?0.7 ?m is incident.

Abstract: An optical recording medium which is a multilayer optical recording medium including a plurality of recording layers and records or reproduces information by the irradiation of light having a wavelength of ?0. At least one recording layer out of a plurality of recording layers includes a variable absorption film. The variable absorption film contains a material in which an electron energy has a band structure, and the absorption end of an absorption spectrum moves toward a longer wavelength side with a rise in temperature when light is absorbed by transition between electron bands, has a first absorptance to light having a wavelength of ?0 when a film temperature is a first temperature (application environment temperature), and has a second absorptance higher than the first absorptance to light having a wavelength of ?0 when a film temperature is a second temperature higher than the first temperature.

Abstract: A first diffractive optical element pattern with a pattern pitch that is no greater than a wavelength of incident light is formed on a first main surface of substrate such as a glass plate. Second diffractive optical element patterns are formed at positions that are respectively incident to positive first-order diffracted light and negative first-order diffracted light produced by the first diffractive optical element pattern. Negative first-order diffracted light produced by each second diffractive optical element pattern is incident upon a boundary face of the substrate at an angle that is smaller than the critical angle, and so exits the substrate.

Abstract: The present invention relates to an optical head device, an optical recording device, and an optical recording method, and an object of the present invention is to enable to acquire optimum recording characteristics of an optical recoding medium having multiple data layers, with respect to each of the multiple data layers without increasing learning time required for learning a relation between aberration amount and optimum recording compensation with respect to each of the multiple data layers. To accomplish this object, the optical head device, the optical recording device, and the optical recording method of the present invention are constructed such that the wavefront converting means 4 is driven in such a manner as to reduce the aberration amount detected by the aberration detecting means 12.

Abstract: An information recording medium has a recording portion where three-dimensional information can be recorded. The recording portion includes at least one particle-containing layer (recording layer or a recording auxiliary layer) containing particles absorbing at least a part of light having a predetermined wavelength and substantially transparent to a recording light and a reproducing light having a wavelength longer than the predetermined wavelength and a particle holding material substantially transparent to the recording and reproducing lights. The mean particle size of the particles is preferably shorter than the wavelengths of the recording and reproducing lights.

Abstract: A diffractive optical element emits substantially zero order diffracted light when light with a wavelength of 0.35 ?m to 0.45 ?m is incident and emits substantially first-order diffracted light when light with a wavelength of 0.6 ?m to 0.7 ?m is incident. The diffractive optical element includes a substrate and a grating portion formed on the substrate. The grating portion has a step-wise cross section with any one of levels selected from four levels, five levels and six levels. The diffractive optical element emits substantially zero-order diffracted light when light with a first wavelength ?1 satisfying the relationship: 0.35 ?m??1?0.45 ?m is incident and emits substantially first-order diffracted light when light with a second wavelength ?2 satisfying the relationship: 0.6 ?m??2?0.7 ?m is incident.

Abstract: An optical information reproducing method of the present invention is used for an optical recording medium. The optical recording medium includes a recording layer containing information and a mask layer that is located close to the recording layer and includes a nonlinear optical material whose optical properties are changed in accordance with incident light intensity. The method includes irradiating the optical recording medium with convergent light that is polarized in a first direction and dividing reflected light from the optical recording medium into a first polarized component that is polarized in the first direction and a second polarized component that is polarized in a second direction perpendicular to the first direction. The second polarized component is used to detect a reproduction signal.

Abstract: An optical head with high light utilization efficiency that includes a diffractive optical element and a light source emitting beams with a plurality of wavelengths that can read plural types of information recording media. A beam emitted from a light source selectively emitting a beam with a first wavelength and a beam with a second wavelength that is approximately twice as long as the first wavelength is collimated into a parallel beam by a diffraction collimator lens, is bent by a mirror for bending an optical path, and then is focused by a diffraction objective lens on an information recording medium. Outgoing light from these diffractive lenses is substantially a second-order diffraction light with respect to the beam with the first wavelength and is substantially a first-order diffraction light with respect to the beam with the second wavelength.

Abstract: A first diffractive optical element pattern with a pattern pitch that is no greater than a wavelength of incident light is formed on a first main surface of substrate such as a glass plate. Second diffractive optical element patterns are formed at positions that are respectively incident to positive first-order diffracted light and negative first-order diffracted light produced by the first diffractive optical element pattern. Negative first-order diffracted light produced by each second diffractive optical element pattern is incident upon a boundary face of the substrate at an angle that is smaller than the critical angle, and so exits the substrate.

Abstract: An optical recording and/or reproduction apparatus includes: a light source for emitting a first light beam; an optical system for outputting first and second diffracted light beams and a second light beam; and a controlling section for controlling the optical system, wherein the first and second diffracted light beams interfere with each other to generate interference fringes which extend in a direction substantially perpendicular to a recording layer of an recording medium, the optical recording and/or reproduction apparatus further includes a detection section for detecting the interference fringes reflected by the guiding portion so as to output a detection signal, and the control section controls the optical system based on the detection signal such that the optical spots follow at least either of concave portions and convex portions of the guiding portion.

Abstract: An optical head device includes: an optical element collecting light reflected from a reproduction information layer (a target information layer in an optical information recording medium) and light reflected from information layers adjacent to the reproduction information layer at different positions; a light receiving element obtaining a detection signal from the reflected light collected by this optical element; and arithmetic circuitry obtaining a reproduction signal from this detection signal.

Abstract: A recording and/or reproduction apparatus, for an information medium including a substrate having concave and convex portions and a plurality of recording layers, includes a light source for emitting a light beam; an optical system for diffracting the light beam emitted by the light source so as to output a first diffracted light beam and a plurality of second diffracted light beams; and a driving section for driving the optical system. The optical system outputs the first diffracted light beam and the second diffracted light beams, such that when one of the second diffracted light beams is converged to and reflected by one of the concave and convex portions, the first diffracted light beam is converged to one of the recording layers. The driving section drives the optical system, such that the one of the second diffracted light beams is converged to the one of the concave and convex portions.

Abstract: A first diffractive optical element pattern with a pattern pitch that is no greater than a wavelength of incident light is formed on a first main surface of substrate such as a glass plate. Second diffractive optical element patterns are formed at positions that are respectively incident to positive first-order diffracted light and negative first-order diffracted light produced by the first diffractive optical element pattern. Negative first-order diffracted light produced by each second diffractive optical element pattern is incident upon a boundary face of the substrate at an angle that is smaller than the critical angle, and so exits the substrate.

Abstract: An optical head according to the present invention includes: a first light source for emitting light with a first wavelength; a second light source for emitting light with a second wavelength longer than the first wavelength; and an objective lens for focusing the lights with the first and second wavelengths on information recording surfaces of information recording media corresponding to the lights with the respective wavelengths. The objective lens is designed so as to reduce aberration with respect to the light with the first wavelength. An optical-path length from the second light source to the objective lens is allowed to be shorter than that from the first light source to the objective lens so that aberration caused by the objective lens due to chromatic dispersion caused by a material of the objective lens is reduced with respect to the light with the second wavelength.

Abstract: An information recording and reproducing apparatus in accordance with the present invention has a radiation light source, a collimator turning a light beam emitted from the radiation light source into substantially parallel light, a light beam convergence member focusing the light beam on an information carrier, a light beam polarization-branching member branching the light beam by polarization, a variable wave plate located between the collimator and the light beam convergence member, photo detectors receiving the light beam branched by the light beam polarization-branching member and outputting a current according to an incident light quantity, and an output level judging member judging whether an output of the photo detectors is larger or smaller than a predetermined value.

Abstract: A diffractive optical element emits substantially zero order diffracted light when light with a wavelength of 0.35 &mgr;m to 0.45 &mgr;m is incident and emits substantially first-order diffracted light when light with a wavelength of 0.6 &mgr;m to 0.7 &mgr;m is incident. The diffractive optical element includes a substrate and a grating portion formed on the substrate. The grating portion has a step-wise cross section with any one of levels selected from four levels, five levels and six levels. The diffractive optical element emits substantially zero-order diffracted light when light with a first wavelength &lgr;1 satisfying the relationship: 0.35 &mgr;m≦&lgr;1≦0.45 &mgr;m is incident and emits substantially first-order diffracted light when light with a second wavelength &lgr;2 satisfying the relationship: 0.6 &mgr;m≦&lgr;2<0.7 &mgr;m is incident.

Abstract: An optical recording and/or reproduction apparatus includes: a light source for emitting a first light beam; an optical system for outputting first and second diffracted light beams and a second light beam; and a controlling section for controlling the optical system, wherein the first and second diffracted light beams interfere with each other to generate interference fringes which extend in a direction substantially perpendicular to a recording layer of an recording medium, the optical recording and/or reproduction apparatus further includes a detection section for detecting the interference fringes reflected by the guiding portion so as to output a detection signal, and the control section controls the optical system based on the detection signal such that the optical spots follow at least either of concave portions and convex portions of the guiding portion.

Abstract: A recording and/or reproduction apparatus, for an information medium including a substrate having concave and convex portions and a plurality of recording layers, includes a light source for emitting a light beam; an optical system for diffracting the light beam emitted by the light source so as to output a first diffracted light beam and a plurality of second diffracted light beams; and a driving section for driving the optical system. The optical system outputs the first diffracted light beam and the second diffracted light beams, such that when one of the second diffracted light beams is converged to and reflected by one of the concave and convex portions, the first diffracted light beam is converged to one of the recording layers. The driving section drives the optical system, such that the one of the second diffracted light beams is converged to the one of the concave and convex portions.

Abstract: An optical head comprises a light path alteration member (first surface of a first transparent substrate), a first grating element and a second grating element arranged in that order in a light path between a light source and an optical disk. A beam emitted by the light source passes a collimated lens, is deflected by total reflection from the light path alteration member, and enters the first grating element. Diffracted light enters a second grating element, and is focused on a recording medium by an objective lens. Wavelength variations in light diffracted by the first grating element and wavelength variations in light diffracted by the second grating element at least partially cancel each other out. Thus, a thin optical head for an optical recording medium is provided.