Abstract: An optical pickup apparatus includes an optical pickup, and a turntable for holding an optical recording medium is placed. A protective cover is arranged between the optical recording medium placed on the turntable and the optical pickup and protects the optical pickup. A heat conducting member connects the optical pickup and the protective cover, and conducts heat generated in the optical pickup to the protective cover.

Abstract: There is provided an optical pickup device comprising a laser light source for emitting a laser beam, an object lens for focusing the laser beam onto the recording surfaces of layers 0 and 1 of an optical disk and condensing the laser beam onto the recording surfaces, photodetectors for receiving the laser beam reflected by the optical disk, and a diffraction grating for diffracting a part of the reflected laser beam toward the photodetectors, wherein data can be simultaneously written to layers 0 and 1. The photodetector detects the reflected light from layer 0 after being refracted by the diffraction grating, and detects the reflected light from layer 1 without being refracted, so that the data of layers 0 and 1 can be simultaneously read. Thus, data can be simultaneously read from and written to the recording surfaces of a plurality of layers of an optical disk.

Abstract: A hologram recording apparatus includes a laser light source for emitting laser light, a light splitter for splitting the laser light emitted from the laser light source into a signal beam and a reference beam, a light modulator for modulating the signal beam split by the light splitter, a phase modulator for phase-modulating the reference beam split by the light splitter, an optical system for collecting the signal beam modulated by the light modulator and the reference beam phase-modulated by the phase modulator onto almost the same collecting position on a hologram recording medium, a collecting-position control mechanism for controlling the collecting position along a surface of the hologram recording medium, and a distance control mechanism for controlling the distance between the phase modulator and the hologram recording medium.

Abstract: An optical pickup device includes a light source to emit light, an objective lens to focus the light on a recording medium to form a light spot, an optical path changer on an optical path between the light source and the objective lens to change the path of incident light, a chromatic aberration correction lens disposed on an optical path between the light source and the objective lens, and a photodetector to receive light which is reflected from the recording medium and is then incident thereon through the optical path changer. The chromatic aberration correction lens corrects a chromatic aberration occurring due to a change in the wavelength and/or due to an increase in a wavelength bandwidth of the light. The chromatic aberration correction lens includes at least two lenses such that a lens having a positive power and a lens having a negative power are adjacent to each other.

Abstract: When an optical information recording/reproducing apparatus receives a request for accessing to an optical information recording medium from a host computer, an optical pickup unit reads an access-restriction code that is recorded on a ROM data-layer of the optical information recording medium, a comparing unit compares the read access-restriction code with a key unique-code that is recorded on an IC card, and a controller determines whether accessing to the optical information recording medium is allowable based on a result of the comparison.

Abstract: A holographic recording system with a simple structure is provided that can make a holographic recording beam follow a recording medium traveling even at high speed. The holographic recording system 10 includes a chopper lens 30 that travels in synchronization with and in a same direction as the holographic recording medium 14. The chopper lens 30 is formed so as to move the axes of incident information and reference beams relative to the recording medium and the chopper lens, and to irradiate them to an identical information recording region 15 in the holographic recording medium 14.

Abstract: A phase shift element has a tiered phase difference pattern portion, in which an inner circular side tiered phase difference pattern portion is continuously connected with an outer circular side tiered phase difference pattern portion based on a phase function curve obtained by a single phase-function with a wavelength having the same value as a reference wavelength ?1 of a first laser light being determined as a designed wavelength ?, formed in annular shapes on one surface thereof. A tier pitch of tiers of the inner circular side tiered phase difference pattern portion is set to a height corresponding to a phase difference of substantially 1? and, on the other hand, a tier pitch of tiers of the outer circular side tiered phase difference pattern portion is set to a height corresponding to a phase difference of substantially m? (where m is a natural number which does not include 0) or a height corresponding to the phase difference of substantially m? by changing a value of m for each step.

Abstract: Information light modulated and emitted by a modulation element is led to a recording medium through a Fourier transform optical system and an optical path shifter. An interference image is recorded on the recording medium by interference of the information light and reference light. A deflection unit of the optical path shifter has a pair of prisms. Optical path of information light transmitted through the respective prisms are shifted in parallel in a direction perpendicular to an optical axis of the Fourier transform optical system. By rotating the deflection unit around the optical axis, it is possible to shift the optical path of the information light around the optical axis while shifting the optical path in the direction perpendicular to the optical axis. Therefore, it is unnecessary to perform complicated control and it is possible to multiply record an interference image accurately with an information recording apparatus having a simple structure.

Abstract: In a multilayer optical disc having information layers conforming to a plurality of different optical disc standards, because the type of each information layer is not recorded in the other information layers, in read and write operations by a compatible optical disc device conforming to a plurality of optical disc standards, every time the information layer being accessed changes, it has been necessary to read the type of the information layer and select a method of generating a tracking error signal adapted to the type of information layer, so access has taken time. In order to solve the above problem, in the optical multilayer disc according to the present invention, having information layers conforming to a plurality of different optical disc standards, in an area in one of the information layers, information about the other information layers is recorded. The time required to access the other information layers can be reduced by using this information to select a tracking error signal generating method.

Abstract: In a beam shaping device for converting the laser light emitted from a semiconductor laser light source from an elliptic beam to a circular beam, the light-entrance-side and light-exit-side surfaces of the beam shaping device both have a curvature only in the minor-axis direction of the cross section of the elliptic beam. Of the light-entrance-side and light-exit-side surfaces, one is a circular-arc cylindrical surface and the other is a non-circular-arc cylindrical surface. The beam shaping device fulfills prescribed conditions with respect to the center thickness, surface shapes, and/or other features.

Abstract: In the optical pickup device, a luminous flux emitted from a blue-violet laser as S wave to a blue-violet PBS, passes through a half-wave plate, and is reflected by the blue-violet PBS and a total reflection mirror, before being applied to a BD disc via an objective lens. Luminous fluxes, which were emitted respectively from an infrared laser emitting device and a red laser emitting device and were reflected respectively by infrared and red PBSs, among aligned infrared, red and blue-violets PBSs, before reaching the blue-violet PBS, are reflected by the blue-violet PBS. The luminous fluxes emitted from the blue-violet laser emitting device as P waves pass the blue-violet PBS, and are respectively applied to a CD disc, a DVD disc, or a HD-DVD disc via an diffractive object lens. Thus, it becomes possible to write or read access to four kinds of discs with three wavelengths.

Abstract: An optical disk compliant with both a conventional optical disk such as a BD, HD DVD, and the like and a next-generation high-density optical disk according to a near-field light recording system and the like is provided. An information recording medium includes a first information recording layer and a second information recording layer, to/from which information is recorded or reproduced using laser beam. The first information recording layer is formed at a laser beam entrance surface, and is configured so that information can be recorded thereupon and/or reproduced therefrom using a first objective lens having a first numerical aperture NA1 and laser beam of a first wavelength ?1. The second information recording layer is formed so as to have a distance to the laser beam entrance surface is 0.05 mm to 1.

Abstract: A spherical aberration compensation actuator and an optical pickup system are provided. The spherical aberration compensation actuator mounts an element for compensating a spherical aberration and operates to a single-axis direction on an optical path using electromagnetic force. The optical pickup system includes a laser diode, an object lens, a spherical aberration compensation actuator, an optical path changer, and an optical detector. The spherical aberration compensation actuator is installed on an optical path between the laser diode and the object lens and includes a lens holder having a spherical aberration compensation element for compensating a spherical aberration generated due to light passing through the object lens and operating in an optical-axis direction using electromagnetic force.

Abstract: An optical element has a dichroic film held between transparent materials which transmits one of first light in a wavelength range of 390 to 425 nm and second light in a wavelength range of 630 to 820 nm and reflects the other light, and a first, a second, a third and a fourth surfaces. In the optical element, a first anti-reflection film for preventing reflection of the first light is formed on the first surface, a second anti-reflection film for preventing reflection of the second light is formed on the second surface, and a third anti-reflection film for preventing the reflection of the first and the second light is formed on the third surface from which the incident light of the first surface and the second surface is emitted. In the third anti-reflection film, reflectance of the second light is larger than that of the first light.

Abstract: A system and method are provided for maintaining optical energy density on a marking area of a storage medium. The method includes the operation of directing a light beam from a light source to an optical system. The light beam can pass through at least one optical component in the optical system, where the optical system has astigmatic properties selected so as to maintain an irradiance within a defined area on the marking area of the storage medium through a range of working distances between the optical system and the marking surface. A further operation is guiding the light beam by the optical system onto the marking area of the storage medium.

Abstract: An optical pickup device includes an optical pickup base having an opening through which reflected light from an optical disc passes to the outside, a light-receiving element shaped like a substantially rectangular plate and configured to convert the reflected light passing through the opening into an electrical signal, and a holder configured to hold the light-receiving element while surrounding a side face of the light-receiving element and attached in contact with an outer wall around the opening so that a light-receiving surface of the light-receiving element faces the opening. The optical pickup base and the holder are formed so that the holder can slide along a first axis parallel to the outer wall, and the holder is formed so that the light-receiving element can slide along a second axis perpendicular to the outer wall and a third axis orthogonal to the first axis and parallel to the outer wall.

Abstract: The optical head device for carrying recording/reproducing of data by irradiating a recording face of an optical disk with a laser beam, includes a base frame provided with an optical system for guiding the laser beam to the optical disk; and a sub-frame provided with a semiconductor laser for and fixed to the base frame. In this optical head device, a diamond-like carbon (DLC) film is formed on the mating faces of the base frame and the sub-frame, respectively.

Abstract: This invention directs to an optical disc assembly configured to receive an analyte which can be detected by a standard optical disc reader or an optical disc reader modified therefrom. The optical disc assembly may preferably be designed so that the optical disc reader can track the disc and detect the analyte concurrently and discriminably. The optical disc assembly contains or encodes optically readable features which are trackable by the optical disc reader and which have encoded speed information enabling the optical disc reader to rotate the optical disc assembly at a determinable speed. The optical disc assembly also includes an analyte section capable of receiving the analyte that can be detected by the optical disc reader.

Abstract: An optical pickup equipped with a laser light source which emits light beams of at least three wavelengths for recording/reproducing a plurality of information recording media detects light quantities of the light beams of three wavelengths using one light intensity monitor element. More specifically, one light intensity monitor element is arranged between a first laser light source and a second laser light source, light beams of wavelength ?1 and wavelength ?2 emitted from the first laser light source are made to proceed substantially straightforward, the optical path of the light beam of wavelength ?3 emitted from the second laser light source is changed to a diagonal one so as to cause the light beam to be introduced diagonally to the light receiving surface of the one light intensity monitor element.

Abstract: An optical scanning device for scanning first and second type of record carriers includes a radiation-generating device for generating a radiation beam having first and second wavelengths in the different modes. An objective system focuses the radiation beam on the record carrier. An optical element is provided having a structure in the radiation beam for introducing vergence and aberration in the radiation beam of the second wavelength. The aberration may be written as a polynomial with at least two terms a2?2 and a4?4. If a2=0 and a4=0, the corresponding values of a4 and a2 are given by a40 and a20, respectively. a2, a4, a20 and a40 satisfy the relation 0.9<((a2/a20)+(a4/a40))<1.1, as well as either the relation 0.20<(a2/a20)<0.90 (if a40) or the relation 1.05<(a2/a20)<2.00 (if a4<0).

Abstract: An optical pickup which, when a first light reflected by a recording medium is divided into a central light area and first and second peripheral light areas at both sides of the central light area, divides the first light reflected by the recording medium into at least 6 light areas, and the at least 6 light areas are independently detected from first through sixth light-receiving portions of a photodetector. Hence, the photodetector can detect a tracking error signal whose offset generation due to a shift of an objective lens is insensitive and whose offset generation due to an initial photodetector balance deviation is depressed.

Abstract: There is provided an objective lens used for an optical information recording/reproducing device for recording information to and/or reproducing information from two types of optical discs, by selectively using one of two types of substantially collimated light beams including first and second light beams. When wavelengths of the first and second light beams are respectively represented by ?1 (nm) and ?2 (nm), ?1<?2 is satisfied. The objective lens includes a first optical element, and a second optical element made of material different from that of the first optical element. The first and second optical elements are cemented via a cementing surface. Further, the objective lens is configured to satisfy a condition: 0.006 < { ( nR ? ? 2 - nR ? ? 1 ) - ( nB ? ? 2 - nB ? ? 1 ) } × ? [ { ( k ? ? 2 r ? ? 2 3 ) + 8 × A ? ? 42 } × f ? ? 1 3 + 2.29 ] < 0.

Abstract: A catadioptric objective system used for storage and/or reproduction of information by use of an optical near field. The catadioptric objective system is composed of a catadioptric objective lens and a light transmitting plate. The lens has a first surface and a second surface. The first surface has a positive optical power and transmits incident rays. The second surface has a positive optical power and reflects incident rays, and a plane portion is formed in the center of the second surface. The light transmitting plate has a third surface and a fourth surface which are substantially parallel to each other, and the third surface is bonded to the second surface. Incident rays pass through the first surface and are reflected by the second surface. Thereafter, the rays enter into the first surface again and are reflected by the first surface. Then, the rays pass through the plane portion of the second surface, and the rays are converged in vicinity of the fourth surface.

Abstract: An optical head device is provided with a semiconductor laser, an aberration correcting element for transmitting a beam from the semiconductor laser, a light guiding portion for introducing the beam from the semiconductor laser to the aberration correcting element, and an objective lens for focusing the beam having passed through the aberration correcting element on an optical disc. The aberration correcting element corrects a longitudinal chromatic aberration occurring in the objective lens and a longitudinal chromatic aberration occurring in the light guiding portion excluding the objective lens and the aberration correcting element based on a longitudinal chromatic aberration occurring in the aberration correcting element when the semiconductor laser emits a beam having a wavelength different by a specified wavelength difference.

Abstract: A molecular data storage device and method thereof are disclosed. In an aspect, the molecular data storage device includes a laser source for providing a photon beam, a beam splitter for splitting the photon beam to provide a first and second coherent beams, a data page modulator for encoding with the first beam to provide a signal beam and a storage material disposed such that the first beam and the second beam enters orthogonal faces thereof.

Abstract: An optical system (20) for efficiently collimating an elliptical light beam includes a light source (21), a collimator (22), and at least one prism (23,24). The light source is adapted for providing an elliptical light beam defining different diverging angles in different directions, wherein any cross-section of the elliptical light beam emitted from the light source defines a long axis and a short axis which are perpendicular to each other. The at least one prism is used for reconfiguring the elliptical light beam, thus obtaining a parallel round light beam having equivalent short axis and long axis.

Abstract: An adjustment apparatus for adjusting an optical pickup capable of recording and/or reproducing optical discs of different sorts. The adjustment apparatus is an adjustment optical disc having a first signal recording layer of a physical format in common with a CD and a second signal recording layer of a physical format in common with a DVD. On the first and second signal recording layers, there are concentrically recorded EFM modulated data. The respective signal recording layers are provided with recording areas that are not overlapped with each other.

Abstract: An optical pickup apparatus for conducting at least recording or reproducing of information on two types of optical information recording media having protective substrates with different thicknesses, includes: a first light source for emitting a first light flux with a wavelength ?1; a first objective lens for converging the first light flux on an information recording surface of a first optical information recording medium when the optical pickup apparatus reproduces or records information for the first optical information medium; and a second objective lens for converging the first light flux on an information recording surface of a second optical information recording medium when the optical pickup apparatus reproduces or records information for the second optical information medium, wherein effective diameters of the first objective lens and the second objective lens are substantially same.

Abstract: A conventional broadband quarter-wave plate has not completely solved the wavelength dependence and has different efficiencies of shifting the phase by 90° depending on the wavelengths, and therefore has a problem that it cannot fulfill the strict specifications on the optical characteristics which are demanded of a wave plate from a viewpoint of the optical efficiency and the like in an optical pickup device compatible with a plurality of different wavelengths.

Abstract: Lens aberration in an objective lens for recording and reproducing optical information, which is composed of a molded aspherical single lens, is inhibited while at the same time good lens productivity is attained. Also attained are excellent optical properties and high production efficiency in a mold processing step and a press molding step conducted to manufacture the lens. To this end there is provided an objective lens 1 having a convex aspherical surface formed at a first surface and a numerical aperture NA which satisfies the condition NA?0.8. It is preferable to have an aspherical surface also at the second surface.

Abstract: An optical pickup device includes: a light source that emits a light beam; a divergence-angle converting lens that converts an angle of divergence of the light beam emitted from the light source and emits the light beam; and an object lens displaceable in a tracking direction that receives incidence of the light beam, the angle of divergence of which is converted by the divergence-angle converting lens, and converges and emits the light beam, wherein spherical aberration equivalent to an amount that can offset astigmatism caused when the object lens is displaced is given to the divergence-angle converting leans, and spherical aberration that can offset the spherical aberration given to the divergence-angle converting leans is given to the object lens and comatic aberration that can offset comatic aberration caused by the spherical aberration given to the divergence-angle converting lens when the object lens is displaced is given to the object lens.

Abstract: An optical pickup apparatus for reproducing information from an optical information recording medium or for recording information onto an optical information recording medium, is provided with a first light source for emitting first light flux having a first wavelength; a second light source for emitting second light flux having a second wavelength, the first wavelength being different from the second wavelength; a converging optical system having an optical axis and a diffractive portion, and a photo detector; wherein in case that the first light flux passes through the diffractive portion to generate at least one diffracted ray, an amount of n-th ordered diffracted ray of the first light flux is greater than that of any other ordered diffracted ray of the first light flux, and in case that the second light flux passes through the diffractive portion to generate at least one diffracted ray, an amount of n-th ordered diffracted ray of the second light flux is greater than that of any other ordered diffracted

Abstract: An object of the present invention is 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. The present invention includes a wavefront converter which is driven in such a manner as to reduce the aberration amount detected by an aberration detector. An output controller holds learned data as to the relation between the driving amount of the wavefront converter and the output of a light source, and controls the output of the light source based on the driving amount of the wavefront converter and the learned data.

Abstract: An apparatus comprises a lens, an alignment feature positioned adjacent to a surface of the lens, a detector for producing an alignment signal in response to a portion of incident light reflected by the alignment feature and a portion of the incident light reflected by the surface adjacent to the alignment feature, and an actuator for controlling alignment of the incident light in response to the alignment signal. A method of controlling alignment of the beam of incident light is also provided.

Abstract: There is provided an optical system of an optical pick-up for recording/reproducing data to/from at least two types of optical discs including a first optical disc and a second optical disc whose recording density is higher than that of the first optical disc. The optical system is provided with a light source unit for the first and second optical discs, an objective lens, and a photo detector. The optical system further includes an optical surface to satisfy compatibility between the at least two types of optical discs, the optical surface being located between the light source unit and one of the at least two type of optical discs. The optical surface has an inner region having a numerical aperture for the first optical disc, an outer region located having a numerical aperture for the second optical disc, and an intermediate region that is located within the outer region at a periphery of the inner region.

Abstract: An optical pick-up including a first objective lens having a numerical aperture (NA) suitable for a BD, a second objective lens having an NA suitable for an HD-DVD, a light source to emit light beams suitable for the BD and the HD-DVD, a first beam splitter to transmit and reflect the emitted beams emitted to be selectively guided to one of the first and second objective lenses, a grated diffraction element to split the emitted beams into a zeroth order main beam and ±1st order sub-beams that can be projected on a single track of the BD and the HD-DVD in series, a first optical detector to receive a beam reflected by and returned from the BD, and a second optical detector to receive a beam reflected by and returned from the HD-DVD, wherein the first and second optical detectors are positioned at similar distances from the first beam splitter.

Abstract: The present invention provides an optical pickup device employing a disc protector that includes a plurality of first protrusions and at least one second protrusion disposed on the lens holder, wherein the first protrusions are formed by applying a first adhesive to a plurality of areas of a top surface of the lens holder, wherein the first protrusions are arranged at different locations in the tracking direction such that the objective lens is sandwiched between the first protrusions, wherein the at least one second protrusion protrudes is formed by applying a second adhesive to at least one area of the top surface of the lens holder, and wherein tips of the first protrusions are closer to the optical disc than a tip of the at least one second protrusion.

Abstract: The track jumping of a scanner on optical storage media in which information items are stored on groove and land tracks or which have not yet been written to is intended to be made possible in a reliable manner. For this purpose, firstly a fictitious track type is defined for a regulating circuit, which regulates the position of the scanner. The regulating circuit is then closed on the basis of the track type defined and a track scanning signal. The reaction of the scanner to the closing is detected in order to obtain from this an item of information about the track type. This method is also advantageous, in principle, for closing the track following regulation in information carriers having relatively high storage densities.

Abstract: An optical pickup head compatible with multiple optical recording media includes three light sources, a prism unit disposed beside the light sources, a reflective multi-surface prism disposed beside the prism unit for multiple reflecting light beams therethrough, a collimating lens disposed beside the reflective multi-surface prism for collimating light beams there through, and an objective lens. The prism unit includes a first portion facing the first light source for passing the first light beam therethrough, a second portion facing the second light source for passing the second light beam therethrough, a third portion facing the third light source for passing the third light beam therethrough, a first aspherical surface for correcting aberrations of the first light beam caused by non-matching, and a second aspherical surface for correcting aberrations of the second light beam caused by non-matching.

Abstract: An optical scanning device for scanning a record carrier (22), the record carrier has an outer face (24) and the optical scanning device comprises a radiation source system (2) arranged to generate a radiation beam; an objective system (20) having an exit face (76) and which is arranged between the radiation source system and the record carrier and provides for evanescent coupling of the radiation across a gap between the exit face of the objective system and the outer face of the record carrier; and a radiation detector arrangement for detecting radiation after interaction with the record carrier. The radiation detector arrangement is arranged to produce a tilt error signals (?, ?) representing a tilt misalignment between the exit face of the objective system and the outer face of the record carrier.

Abstract: An optical pickup device, comprises light sources to emit a first light flux having a wavelength ?1 (380 nm<?1<450 nm); a second light flux having a wavelength ?2 (600 nm<?2<700 nm); and a light-converging optical system. The light-converging optical system converges the first light flux on a first optical information recording medium through a protective layer having a thickness t1 and the light-converging optical system converges the second light flux on a second optical information recording medium through a protective layer having a thickness t2. The light-converging optical system forms a first spot on the information recording surface of the first optical information recording medium by using N-th order diffracted light ray generated, and the light-converging optical system forms a second spot on the information recording surface of the second optical information recording medium by using M-th order (M?N) diffracted light ray generated.

Abstract: An optical disk device has a light source which emits light; and light converging means of, in each of signal mark forming regions, each of lands, or each of grooves of an optical disk, converging the light from the light source onto a signal surface of the optical disk with selectively positioning a signal mark at any one of plural positions which are arranged in a direction that is substantially perpendicular to tracks, each of the signal mark forming regions surrounded by adjacent two of boarder lines which are between two the tracks on the signal surface of the optical disk, and which are substantially parallel to the tracks, and each of which substantially divides an area between adjacent tracks in two parts.

Abstract: A holographic optical accessing system includes a light source for emitting a light beam; an optical assembly module for receiving the light beam and generating a signal beam and a reference beam that are parallel to each other rather than overlap with each other, and have the same first polarization state; a lens module for focusing the signal beam and the reference beam on a focal point at the same time; and a storage medium for recording the focal point. The optical assembly module includes at least a data plane for displaying image information so that the signal beam contains the image information.

Abstract: An optical disk unit, for reading signals stored on an optical disk medium, is provided with an optical pickup 23 selectively irradiating light of one wavelength, from several mutually different wavelengths, to an optical disk medium by means of a single objective lens and outputting signals based on light reflected by the optical disk medium, a drive section for causing relative movement of the objective lens of the optical pickup with respect to a surface of the optical disk medium, wherein a peak level of a fake signal generated in the received light signal based on surface reflection at the optical disk surface while the objective lens is being moved relative to the optical disk medium surface by the drive section is detected, and the received light signal is compared with a threshold value that is set based on the detected peak level, to detect reflected light of a data storage layer.

Abstract: A compatible optical pickup includes an optical disc, an objective lens, a diffractive device, and a divergent lens. The optical unit emits a short wavelength light beam corresponding to a high density optical disc and a long wavelength light beam corresponding to a low density optical disc. The objective lens forms a light spot on the high density optical disc and the low density optical disc and the diffractive device diffracts the short wavelength light beam to correct chromatism according to a change in a wavelength of the short wavelength light beam. The divergent lens refracts the long wavelength light beam toward the objective lens to increase a working distance with respect to the low density optical disc.

Abstract: A diffractive optical element, comprises a first diffractive structure to generate n11-th order diffracted ray when a first light flux having ?1 (nm) of a wavelength comes in and to generate n21-th order diffracted ray (n11.?n21) when a second light flux having ?2 (nm) (?2>?1) comes in; and a second diffractive structure to generate n12-th order diffracted ray when the first light flux comes in and to generate n22-th order diffracted ray (n12.?n22) when the second light comes in. The diffractive optical element satisfies the following formula: ??A12???B12, where ??A12={n11·?1/(N11?1)}/{n21·?2/(N21?1)}, and ??B12={n12·?1/(N12?1)}/{n22·?2/(N22?1)}, wherein N11, N21 are refractive index of the first diffractive structure respectively for ?1 and ?2, and N12, N22 are refractive index of the second diffractive structure respectively for ?1 and ?2.

Abstract: An semiconductor laser light source apparatus includes: a semiconductor laser oscillator for emitting a laser beam; and a lens for transmitting the laser beam emitted by the semiconductor laser oscillator, wherein the lens comprises a light transparent material in which microparticles are dispersed into a plastic resin and have a size of the transmitting laser beam wavelength or below.

Abstract: A light source, an objective lens which concentrates light from the light source onto an information recording surface of an information storage medium, and a spherical aberration correction mechanism provided on a light path between the light source of the objective lens are provided. The spherical aberration correction mechanism includes a piezoelectric element for moving a coupling lens, a photo interrupter which detects whether the coupling lens has been moved to an initial position, and a spherical aberration correction element control circuit which moves the coupling lens, which has been moved to the initial position, to one of first to n-th (n is an integer not less than 2) positions where light is concentrated onto an information recording surface of one of first to n-th layer of the information storage medium, the distances between the initial position to the respective first to n-th positions having been determined in advance.

Abstract: A method and an optical disk apparatus that can accurately and stably correct the spherical aberration even for a blank write-once optical disk and can detect a spherical aberration error signal with a simple construction of parts in real time. In a blank write-once disk 20, the tracking servo is switched to an inoperative state, push-pull signals from outputs of the photodetector 12 are detected in a state of “in focus” and in a state of “out focus,” respectively, by a push-pull signal generation circuit 34, and.the amplitudes of these push-pull signals are subjected to difference calculation in a spherical aberration error detector 31 to obtain a spherical aberration error signal A.

Abstract: It is an object of the present invention to provide an optical pick-up device capable of being miniaturized by reducing the number of components. The present invention provides an optical pick-up device including a light-emitting device having an organic compound that emits laser light upon applying current. The light-emitting device interposes an organic compound layer between a pair of electrodes. The organic compound layer, which is a main component, has a layer configuration for emitting a laser beam. In the layer configuration, the thickness of each layer is determined in consideration of the wavelength of laser oscillation. The organic compound layer is composed of a plurality of layers, each of which has different properties such as carrier transportation properties or light-emitting properties. The organic compound layer is preferably formed to have a so-called resonator structure formed via a reflecting layer.