Abstract: An optical pickup device has a near-field optical system having a numerical aperture of NA>1; a first light source emitting a first light having a first wavelength; a second light source emitting a second light having a second wavelength; an optical system multiplexing the first light and second light and irradiating the multiplexed light onto an optical recording medium having at least two recording layers; a first photodetector detecting the first light returned from the recording medium a second photodetector detecting the second light returned from the recording medium; a controller obtaining a signal corresponding to distance between the near-field optical system and the recording medium based on the returned second light, and obtaining a reproducing signal and a tracking signal of the recording medium and a focus signal corresponding to the recording layer based on the returned first light; and a focus position adjustment mechanism moving a focus position of the first light under control of the focus

Abstract: A solid immersion lens (SIL) is provided. The SIL includes a spherical part, a cone-shaped part, a tip part, and an edge part between the cone-shaped part and the tip part. The edge part includes a curved surface.

Abstract: A signal detecting device includes: a semiconductor substrate; a near-field light generating section that is provided on the semiconductor substrate and generates near-field light near an interface with the semiconductor substrate; a light source that outputs light having wavelength corresponding to photon energy about a half as large as band-gap energy of a material of the semiconductor substrate; and a current detecting unit that detects a photocurrent generated in the semiconductor substrate when the near-field light is generated.

Abstract: An optical disk reproducing device includes: a semiconductor laser for sequentially emitting singular peak light and singular slope light as laser light when supplied with a driving pulse formed in a form of a pulse and formed of a predetermined singular voltage; an objective lens for condensing the laser light onto a recording layer disposed in an optical disk, and converting an angle of divergence of return light returned from the recording layer; a detection signal generating section configured to detect respective light intensities in each of wavelength bands in the return light, and respectively generate a plurality of detection signals according to the respective light intensities; and a reproduction processing section configured to reproduce information recorded on the optical disk on a basis of the plurality of detection signals.

Abstract: A method for manufacturing a master includes the steps of forming an inorganic resist layer on a master-forming substrate and forming, on a surface of the inorganic resist layer, a protective thin film containing a high-refractive-index material which has a refractive index n satisfying n?NA of an exposure optical system and which is mixed in a light-transmitting material, performing near-field exposure with NA>1 on the protecting thin film using an exposure optical system, separating the protective thin film from an inorganic resist master subjected to the exposure, and forming a protrusion/depression pattern including exposed portions and unexposed portions by development of the inorganic resist master from which the protective thin film is separated.

Abstract: A signal detecting device includes: a semiconductor substrate; a near-field light generating section that is provided on the semiconductor substrate and generates near-field light near an interface with the semiconductor substrate; a light source that outputs light having wavelength corresponding to photon energy about a half as large as band-gap energy of a material of the semiconductor substrate; and a current detecting unit that detects a photocurrent generated in the semiconductor substrate when the near-field light is generated.

Abstract: An optical pickup device has a near-field optical system having a numerical aperture of NA>1; a first light source emitting a first light having a first wavelength; a second light source emitting a second light having a second wavelength; an optical system multiplexing the first light and second light and irradiating the multiplexed light onto an optical recording medium having at least two recording layers; a first photodetector detecting the first light returned from the recording medium a second photodetector detecting the second light returned from the recording medium; a controller obtaining a signal corresponding to distance between the near-field optical system and the recording medium based on the returned second light, and obtaining a reproducing signal and a tracking signal of the recording medium and a focus signal corresponding to the recording layer based on the returned first light; and a focus position adjustment mechanism moving a focus position of the first light under control of the focus

Abstract: An optical recording medium illuminated by light from a light source as near-field light using a focusing lens whose numerical aperture exceeds 1 to perform recording and/or reproduction is provided, wherein a composite layer in which a high refractive index material portion having a refractive index higher than that of a light-transmissible material portion is mixed in the light-transmissible material portion is provided on the surface of a light incident side of the optical recording medium. With an average refractive index of the composite layer being high, a numerical aperture controlled by a refractive index of a surface layer can be made large to obtain higher resolution and higher durability against contact with a lens or the like.

Abstract: A solid immersion lens (SIL) is provided. The SIL includes a spherical part, a cone-shaped part, a tip part, and an edge part between the cone-shaped part and the tip part. The edge part includes a curved surface.

Abstract: The present invention is directed to a multi-layered optical recording medium adapted to satisfy reflection factor required at the time of recording/reproduction of digital data based on the standards of CD (Compact Disc) and DVD (Digital Versatile Disc), wherein a first transparent base (12), a HD layer (11), a second transparent base (22) and a CD layer (21) are laminated in order; one semi-transparent layer (31) or more having reflection characteristic with respect to wavelength of a first reproduction signal and having transmission characteristic with respect to wavelength of a second reproduction signal is or are formed on the HD layer; a metallic film (23) having reflection characteristic with respect to wavelength of the second reproduction signal is formed on the CD layer, and total film thickness of the semi-transparent film or films is expressed as ?×m×?×n when wavelength of the second reproduction signal is ? and refractive index of the first transparent base is n (In this expression, 1.0???1.

Abstract: A solid immersion lens includes a spherical part being hemispherical on the side opposite to an object and an anti-reflection coating provided at least in an incidence range of incident light on the hemispherical spherical part.

Abstract: The present invention relates to an optical disc on which an information signal can be rewritten. Guide grooves (81a) for tracking control are formed on respective tracks of the rewritable area where an information signal can be rewritten. A recording layer (83) onto which an information signal is to be written is laminated on a substrate on which the guide grooves (81a) have been formed. The information signal can be rewritten on the recording layer (83) at least in the rewritable area using near-field light based on multibeam. Concave portions (85a) are formed on the outermost surface of the disc recording medium in correspondence with the positions of the guide grooves (81a).

Abstract: An optical recording medium illuminated by light from a light source as near-field light using a focusing lens whose numerical aperture exceeds 1 to perform recording and/or reproduction is provided, wherein a composite layer in which a high refractive index material portion having a refractive index higher than that of a light-transmissible material portion is mixed in the light-transmissible material portion is provided on the surface of a light incident side of the optical recording medium. With an average refractive index of the composite layer being high, a numerical aperture controlled by a refractive index of a surface layer can be made large to obtain higher resolution and higher durability against contact with a lens or the like.

Abstract: An optical device is provided which has a light converging unit for converging the light illuminated on a magneto-optical recording layer of an optical recording medium and a magnetic field generating unit provided on the light converging unit towards the optical recording medium. The diameter of the light beam radiated on the magneto-optical recording layer of the optical recording medium is controlled by a light transmitting hole of the magnetic field generating unit. The light beam illuminated on the magneto-optical recording layer of the optical recording medium is not fluctuated in diameter so that it is possible to produce a magnetic field at a low power consumption. In addition, the magnetic field generating unit is not liable to be ruptured. There is also provided a recording and/or reproducing apparatus employing this optical device.

Abstract: A multilayer optical disk having an information storage layer which can as well as be reproduced by a general purpose reproducing apparatus, for example, a compact disk player, and from which information can be read from other information storage layers by using an exclusive reproducing apparatus. The method of manufacturing a multilayer disk comprises the steps of forming a first substrate having a first information storage area enabling reproduction of information therein with a first light beam having a wavelength of 770 nm to 830 nm; forming a second substrate having a second information storage area enabling reproduction of information therein with a second light beam having a wavelength of 615-655 nm but which is relatively transparent with respect to said first light beam; and bonding said first substrate to said second substrate together without said first and second said information areas facing each other.

Abstract: A multilayer optical disk having an information storage layer which can as well as be reproduced by a general purpose reproducing apparatus, for example, a compact disk player, and from which information can be read from other information storage layers by using an exclusive reproducing apparatus. The method of manufacturing a multilayer disk comprises the steps of forming a first substrate having a first information storage area enabling reproduction of information therein with a first light beam having a wavelength of 770 nm to 830 nm; forming a second substrate having a second information storage area enabling reproduction of information therein with a second light beam having a wavelength of 615-655 nm but which is relatively transparent with respect to said first light beam; and bonding said first substrate to said second substrate together without said first and second said information areas facing each other.

Abstract: An optical disk includes at least two information recording layers on one side of the disk and at least the first information recording layer from the light incident side is of an erasable type formed with a material such as bismuth-substituted magnetic garnet or cobalt ferrite which has an extinction coefficient, a coefficient of an imaginary part of a complex index of refraction, being not more than 1.0, but not less than 0.5, and gives a large magneto-optic effect and a small light absorptivity.

Abstract: A multilayer optical disk having an information storage layer which can as well as be reproduced by a general purpose reproducing apparatus, for example, a compact disk player, and from which information can be read from other information storage layers by using an exclusive reproducing apparatus. The method of manufacturing a multilayer disk comprises the steps of forming a first substrate having a first information storage area enabling reproduction of information therein with a first light beam having a wavelength of 770 nm to 830 nm; forming a second substrate having a second information storage area enabling reproduction of information therein with a second light beam having a wavelength of 615-655 nm but which is relatively transparent with respect to said first light beam; and bonding said first substrate to said second substrate together without said first and second said information areas facing each other.

Abstract: The object of the present invention is to improve the accuracy of a recording signal and a reproduction signal of a magneto-optical recording medium. In a magneto-optical recording medium (2) having at least a metallic reflection layer (3), a back dielectric layer (4), a magneto-optical recording layer (5) and a light transmitting dielectric layer (6) sequentially provided on a substrate (8), the thickness of the light transmitting dielectric layer (6) closer to a convergent lens (1) is set at 50 to 80 nm. Alternatively, the refraction index n of the light transmitting dielectric layer (6) is selected to satisfy the relationship of n0×0.8≦n with the refraction index n0 of the convergent lens (1).

Abstract: A multilayer optical disk having an information storage layer which can as well as be reproduced by a general purpose reproducing apparatus, for example, a compact disk player, and from which information can be read from other information storage layers by using an exclusive reproducing apparatus. The method of manufacturing a multilayer disk comprises the steps of forming a first substrate having a first information storage area enabling reproduction of information therein with a first light beam having a wavelength of 770 nm to 830 nm; forming a second substrate having a second information storage area enabling reproduction of information therein with a second light beam having a wavelength of 615-655 nm but which is relatively transparent with respect to said first light beam; and bonding said first substrate to said second substrate together without said first and second said information areas facing each other.