Abstract: A system and method for providing direct read after write functionality in an optical data storage device include an optical head having a first coherent light source modulated at higher power during writing of data to the optical medium and a second coherent light source operating in a continuous wave mode at lower power while the first coherent light source is writing data. Optic components combine light from the first and second light sources and focus light from the first coherent light source to a first spot of a selected track on the optical medium and focus light from the second coherent light source to a second spot on the selected track downstream from the first spot relative to movement direction of the optical medium to read and verify the data directly after writing during the write process rather than in a separate verification process.

Abstract: An optical pickup apparatus includes: first and second laser diodes to emit first and second laser beams having first and second wavelengths for reading signals recorded in first and second optical discs, respectively; a first objective lens configured to condense the first laser beam onto the signal recording layer of the first optical disc; a second objective lens arranged, along with the first objective lens, in a radial direction of the first and the second optical discs, the second objective lens configured to condense the second laser beam onto the signal recording layer of the second optical disc; a first optical system configured to guide the first laser beam from the first laser diode to the first objective lens; and a second optical system configured to guide the second laser beam from the second laser diode to the second objective lens independently of the first optical system.

Abstract: In the present invention, to improve CD read/write characteristics having poor image height characteristics, a third light emitting source emitting a third laser beam for CD is disposed on an optical axis of an objective lens. Thereby, the third laser beam emitted from the third light emitting source travels along the optical axis of the objective lens, thus generating no coma aberration in the third laser beam. Furthermore, in the present invention, a second light emitting source emitting a second laser beam for DVD and a first light emitting source emitting a first laser beam for BD are disposed across the third light emitting source. Thereby the phase propagation directions of coma aberrations in the first and second laser beams coincide with each other. Adjustment of the coma aberration in one of the laser beams enables the coma aberration in the other laser beam to be adjusted.

Abstract: The invention relates to three-dimensional optical memory devices and can be used in all areas of computing in which it is necessary to record large data files on compact carriers, and also for recording, erasing and reading video data, for example, in independent video viewing systems. The device comprises an optical disc positioning system, a source of radiation with two different wavelengths that is optically coupled to a focusing system, focusing system positioning means, and an optical sensor that is optically coupled to the focusing system via a spectrum splitter and an controlled spectrum selector placed between the source of radiation with two different wavelengths and the spectrum splitter, wherein the focusing system is designed with longitudinal chromatic aberration at the given wavelengths.

Abstract: The present invention discloses a multilevel recording method and system thereof. The multilevel recording method applied to a recording media comprises the following steps. At First, a plurality of beams are provided to a recording layer of the recording media, and the recording layer has a first structure and a second structure. Then, a first polarized reflected light of the first structure and a second polarized reflected light of the second structure are detected by a detecting unit. Then, a corresponding table is stored by a storing unit. The corresponding table comprises a relationship between the different angle of the polarized reflected light and a level of multilevel recording. Finally, the processing unit looks up the corresponding table to process multilevel recording.

Abstract: In a diffractive element, its grating pattern is so configured that a diffraction angle of a diffracted light beam of a light source that is subject to the first-order diffraction in a diffraction area is matched with an angle of a light beam passing through the diffractive area emitted from a light source and a light source position is matched with a light originating point of the light source that emits a light beam to be transmitted, and the center of light intensity distribution is matched with that of the light source passing through the diffractive element by inclining an optical axis of the light source. A position of the diffractive element is adjusted based on an electric current value generated when a reflected return path light beam of the light source is diffracted by the diffractive element and enters the light source.

Abstract: An optical information recording method includes emitting light having a wavelength ?1 from a first light source with a pulse width of time tw1 or more and power P1, emitting light having a wavelength ?2 from a second light source with a pulse width of time tw2, a repetition interval T, and power P2, and performing information recording by simultaneously irradiating an identical part of a recording medium with the light from the first light source and the light from the second light source, in which the wavelength ?1 and the wavelength ?2 satisfy ?1>500 nm>?2 and ?0 which is expressed as 1/?1+1/?2=1/?0 satisfies a relationship of ?0<300 nm, and emission of the first light source and emission of the second light source satisfy relationships of tw2<tw1, T<tw1, and P2>P1.

Abstract: An object of the present invention is to reduce the influence of a stray light incident on a light receiving device by reflection of an unnecessary diffraction light not contributing to write or read on a disc surface at write or read of an optical disc having a large surface reflectivity with respect to an information recording surface. A position in which a diffraction light with an n-order in an advancing path and the n-order in a returning path, reflected on the information recording surface of a first information recording medium, is focused by a condensing lens is different from a position in which a diffraction light different from the n-order diffraction light in at least one of the advancing path and the returning path, reflected on a surface of the first information recording medium, is focused by the condensing lens.

Abstract: An optical pickup device includes a plurality of laser light sources emitting laser beams of different oscillation wavelengths, and a plurality of objective lenses on which the laser beams in the form of diverging beams emitted by the plurality of laser light sources are incident, and which directly focus the laser beams onto a recording surface of an optical disc. A rising mirror reflects a laser beam in the form of a diverging beam emitted by a laser light source of a predetermined oscillation wavelength among the plurality of laser light sources so as to lead the laser beam to one of the plurality of objective lenses, and transmits the laser beam in the form of a diverging beam emitted by the other laser light source. As the rising mirror transmits the laser beam in the form of the diverging beam emitted by said other laser light source, astigmatism is generated so as to correct existing astigmatism of the laser beam emitted by said other laser light source.

Abstract: In the present invention, to improve CD read/write characteristics having poor image height characteristics, a third light emitting source emitting a third laser beam for CD is disposed on an optical axis of an objective lens. Thereby, the third laser beam emitted from the third light emitting source travels along the optical axis of the objective lens, thus generating no coma aberration in the third laser beam. Furthermore, in the present invention, a second light emitting source emitting a second laser beam for DVD and a first light emitting source emitting a first laser beam for BD are disposed across the third light emitting source. Thereby the phase propagation directions of coma aberrations in the first and second laser beams coincide with each other. Adjustment of the coma aberration in one of the laser beams enables the coma aberration in the other laser beam to be adjusted.

Abstract: An optical-pickup apparatus includes: a three-wavelength-laser diode including first-, second-, and third-laser elements to emit first-, second-, and third laser beams having first, second, and third wavelengths, respectively, the three laser elements housed in the same case; an objective lens to focus the three laser beams onto first- to third-optical-disc-signal-recording layers, respectively; a first photodetector to be irradiated with first-return light reflected from the first-optical-disc-signal-recording layer, a second photodetector to be irradiated with second- and third-return lights respectively reflected from the second- and third-optical-disc-signal-recording layers; a polarizing-beam splitter to reflect the three laser beams toward the lens, and allow the three return lights having passed through the lens to pass therethrough; a semitransparent mirror on which the three return lights having passed through the polarizing-beam splitter are incident, and which guide the first-return light toward th

Abstract: A method for assembling an optical pickup apparatus for recording/reproducing a high density DVD, DVD and CD including two objective lens and three laser light sources, the objective lenses being provided on the lens holder having an actuator base for supporting the actuator, the method for assembling the optical pickup apparatus comprises the steps of adjusting a first tilt angle of the actuator base so that a coma aberration of a spot formed by the first light beams decreases when the first light beams are converged onto the first recording medium via the first objective lens, and adjusting a second tilt angle formed between the second objective lens and the lens holder so that a coma aberration of a beam spot formed by the second light beams decreases when the second light beams are converged onto the second recording medium via the second objective lens.