Abstract: One surface of an objective lens is provided with a zonal part which acts such that the quantity of light having a wavelength of &lgr;1 is apparently canceled in the outer peripheral portion of the luminous flux due to an interference effect, whereas the quantity of light having a wavelength of &lgr;2 in the outer peripheral part is kept as it is. The zonal part has such a step that light supposed to pass a position corresponding to the zonal part if the zonal part does not exist and light passing a position at which the zonal part is formed if the zonal part exists generate therebetween a phase difference satisfying a predetermined conditional expression. The numerical aperture at a boundary position of the step has a value between two numerical apertures for the respective wavelengths &lgr;1 and &lgr;2.

Abstract: A lens and combination lens able to suppress deviation of an optical axis of a lens occurring at the time of combination and able to be adjusted at a high precision, a method of producing the combination lens, and an optical pickup device and an optical disk drive mounting the combination lens thereon are provided. A first lens L1 comprising a lens body 1 where one surface on an incident side or an emitting side of light is a flat surface and the other surface parallel to the surface formed as the flat surface is a structural element and a second lens L2 comprising a lens body 2 where one surface on an incident side or an emitting side of light is a flat surface and the other surface parallel to the surface formed as the flat surface is a structural element are adhered together. The combination lens is used as the object lens for an optical pickup device and an optical disk drive.

Abstract: A recording/reproducing apparatus including an optical pickup compatible with a plurality of optical recording media each using light of a different wavelength. The optical pickup includes at least one light source, an objective lens having a function of focusing light emitted from the light source into the optimal light spot on an information recording surface of one of the plurality of the optical recording media, and a light detector to detect light transmitted through the objective lens after being reflected from the information recording surface of the optical recording medium on which the light spot is formed. The objective lens has an inner area, an annular lens area and an outer area such that the annular lens area divides the inner area from the outer area and has a ring shape centered at a vertex. The inner area, the annular lens area and the outer area have aspherical surface shapes.

Abstract: An optical disk, a method for manufacturing an optical disk, an optical disk device and a method for writing/reading an optical disk, wherein the optical disk is of a write/read type having two layers of write films, enabling the state of the write/read beam to be kept constant when writing onto or reading out of a second write film without being affected by variations in the write state of a first write film, is to be provided. In an optical disk configured by stacking, enumerated in the direction of incidence of a write/read beam, a disk substrate, a first write film, an adhesive layer, a second write film, another disk substrate and an aluminum reflective layer, when performing read/write onto or out of a write film which is the second write film, the write/read beam is focused on the second write film after being transmitted by the disk substrate, the first write film, the adhesive layer, the second write film and the other disk substrate and reflected by the aluminum reflective layer.

Abstract: A recording/reproducing apparatus having an optical pickup device which is efficient in light use having little spherical aberration.

Abstract: An optical pickup device for conducting reproducing and/or recording of information in at least two kinds of optical information recording media, comprises a first light source to emit light flux having a first wavelength (&lgr;1) in order to conduct reproducing and/or recording of the information in a first optical information recording medium having a first transparent substrate; a second light source to emit light flux having a second wavelength (&lgr;2) longer than the first wavelength in order to conduct reproducing and/or recording of the information of a second optical information recording medium having a second transparent substrate; a converging optical system for converging the light flux having the first wavelength or the light flux having the second wavelength on the first information recording surface of the first optical information recording medium or on the second information recording surface of the second optical information recording medium; and an optical detector for receiving and detect

Abstract: A read head optical system capable of reading either CD or DVD disks is provided. A monolithic molded hollow plastic block includes three lenses integrally molded into its exterior surfaces. A 780 nm laser diode is aligned with the first lens for reading CD disks, a 655 nm laser is aligned with the second lens for reading DVD disks and a detector for providing signal, focus and tracking data is aligned with the third molded lens. The hollow plastic block has an interior cavity adapted to support optical elements to receive and transmit the output of the laser diodes to the disks and to the detector. The three lenses are formed in the hollow plastic block in various embodiments.

Abstract: An objective lens and an optical head including the objective lens for reading information contained on substrates having different thicknesses using laser beams having different wavelengths. The objective lens includes an annular phase shifter for decreasing an aberration of a focused spot of each of the laser beams. The annular phase shifter can be optimally combined with the objective lens having inner and outer regions each having a different substrate thicknesses.

Abstract: An optical head for an optical disc drive is provided with a first laser diode that emits a shorter wavelength laser beam, a second laser diode that emits a longer wavelength laser beam, and an objective lens for converging the beams emitted by the laser diodes on the data recording surface of the optical disc. Each of first and second surfaces of the objective lens is rotationally symmetrical, and a rotational axis of the first surface and a rotational axis of the second surface are arranged to be deviated from each other.

Abstract: An integrated micro-optical system includes at least two wafers with at least two optical elements provided on respective surfaces of the at least two wafers. An active element having a characteristic which changes in response to an applied field may be integrated on a bottom surface of the wafers. The resulting optical system may present a high numerical aperture. Preferably, one of the optical elements is a refractive element formed in a material having a high index of refraction.

Abstract: An optical apparatus can eliminate offset resulting from assembling errors and also can correct offset even in the photodetector of any optical system. An optical disk apparatus for reading information from tracks traces the track with the condensed spot of light beam depending on the tracking error signal obtained from the optical system for tracking error detection. The tracking error detecting optical system includes an optical apparatus having a photodetector for outputting, as the tracking error signal, a differential value of outputs of a plurality of light receiving sections for receiving the light beam condensed by the condenser lens. Also, an optical element is provided for relatively increasing and/or decreasing the amount of receiving light of a light receiving section depending on displacement of the optical axis of the light beam, in order to balance the light received by the light receiving sections and compensate for affect.

Abstract: An optical data storage medium includes a superstructure of micro-lenses defining first and second repeating periods. One of the periods is longer than the other, and the presence of the longer repeating period allows the medium to be used in an optical drive that is configured to use light diffracted by the longer period for tracking purposes. The micro-lenses may be configured such that adjacent lenses have different heights, widths, or shapes. In some embodiments, the spacing between adjacent data tracks is varied to provide the first and second repeating periods.

Abstract: An optical recording and pickup head having a flat plate lens of a staircase type diffraction grating structure is compatible with a DVD and a CD-RW.

Abstract: In order to reproduce signals from a double-layer optical disc having two signal recording surfaces, a focus jump that the focusing of an objective lens from the one signal recording surface to the other signal recording surface is quickly achieved, is necessary. When a focus error signal (FE) from a pickup (60, 70) reaches a predetermined threshold value (Vcomp), a deceleration signal for decelerating the objective lens (42) is supplied to an actuator (47). Preferably, a deceleration pulse voltage is lowered step by step. The deceleration pulse voltage is determined in accordance with the maximum value (DFEmax) of a differential focus error signal (DFE) generated by differentiating the focus error signal (FE). Preferably, the address seeking is done simultaneously with the focus jump. The focus jump is performed in accordance with the layer-to-layer distance which is measured beforehand. The focus jump is performed by using a lens (143) having a controllable focal distance.

Abstract: An objective lens and an optical head including the objective lens for reading information contained on substrates having different thicknesses using laser beams having different wavelengths. The objective lens includes an annular phase shifter for decreasing an aberration of a focused spot of each of the laser beams. The annular phase shifter can be optimally combined with the objective lens having inner and outer regions each having a different substrate thicknesses.

Abstract: An objective lens and an optical head including the objective lens for reading information contained on substrates having different thicknesses using laser beams having different wavelengths. The objective lens includes an annular phase shifter for decreasing an aberration of a focused spot of each of the laser beams. The annular phase shifter can be optimally combined with the objective lens having inner and outer regions each having a different substrate thicknesses.

Abstract: Disclosed is a short-wave pass filter-inserted objective lens of an optical pickup device for both CD and DVD, in which a short-wave pass (SWP) filter is inserted in the objective lens, thereby being capable of allowing the optical pickup device to have a light-weight, slim, simple, and miniaturized structure. The objective lens is characterized in that it is divided into two lens portions in a transverse direction to a beam transmitting path and provided with a short-wave pass (SWP) filter, the lens portions having planarized divisional surfaces facing each other, respectively. The objective lens reduces the space occupied by the SWP filter. Accordingly, the objective lens of the present invention alleviates a restriction in the design of an optical system caused thereby. Also, there is an advantage in that an increased margin is secured.

Abstract: A solid immersion mirror (SIM) type objective lens and an optical pickup employing the same. The objective lens has a first curved surface which condenses incident light and a second curved surface surrounding the first curved surface which diverges incident light. A second transmission surface disposed to face the first transmission surface has an area which transmits incident light and a first reflection surface surrounding the second transmission surface which reflects incident light. A second reflection surface which surrounds the second curved reflects incident light. The objective lens realizes an NA of 0.7 or more with a single lens; has a working distance enabling far field recording/reproducing; has a smaller blocking area than that of the conventional SIM; and generates a smaller amount of side lobe. Where the objective lens is adopted in an optical pickup device, generation of jitter during reproduction or cross erasure during recording is minimized.

Abstract: An optical apparatus can eliminate offset resulting from assembling errors and also can correct offset even in the photodetector of any optical system. An optical disk apparatus for reading information from tracks traces the track with the condensed spot of light beam depending on the tracking error signal obtained from the optical system for tracking error detection. The tracking error detecting optical system includes an optical apparatus having a photodetector for outputting, as the tracking error signal, a differential value of outputs of a plurality of light receiving sections for receiving the light beam condensed by the condenser lens. Also, an optical element is provided for relatively increasing and/or decreasing the amount of receiving light of a light receiving section depending on displacement of the optical axis of the light beam, in order to balance the light received by the light receiving sections and compensate for affect.

Abstract: An optical pickup apparatus includes a light source for emitting a light flux; and a converging optical system having a first, second, and third divided surface, which are divided in the order named from the vicinity of an optical axis of the converging optical system, for converging the light flux emitted from the light source, wherein a beam spot passing through the first and third divided surfaces is formed onto a first optical information recording medium having a transparent substrate whose thickness is t1, and a beam spot passing through the first and second surfaces is formed onto a second optical information recording medium having a transparent substrate whose thickness is t2 that is more than t1. The optical pickup apparatus further includes an image sensor for receiving a light flux reflected from the first and/or second optical information recording medium.

Abstract: An objective lens and an optical head including the objective lens for reading information contained on substrates having different thicknesses using laser beams having different wavelengths. The objective lens includes an annular phase shifter for decreasing an aberration of a focused spot of each of the laser beams. The annular phase shifter can be optimally combined with the objective lens having inner and outer regions each having a different substrate thicknesses.

Abstract: An optical pickup apparatus for reproducing information from one of different kinds of optical information recording medium, each having a transparent substrate in different thickness, or for recording information onto one of the different kinds of optical information recording medium, the optical pickup apparatus includes: a light source for emitting light flux; a converging optical system having an optical axis, a ring-zonal diffraction section, and a refracting surface including a first divisional portion, a second divisional portion and a third divisional portion. The third divisional portion is farther from the optical axis than the first divisional portion, and the second divisional portion is provided between the first divisional portion and the third divisional portion.

Abstract: An optical element having a substrate formed by an optical material and able to improve mechanical strength, wherein the substrate has a convex part functioning as a convex lens, a flat part positioned around the convex part, and an outer circumference part positioned around the flat part. The thickness of the substrate at the outer circumference part is greater than that of the substrate at the flat part.

Abstract: An optical system of an optical pick-up that is capable of using optical discs DVD and CD. The system includes a light source portion for selectively emitting a first laser beam (650 nm) and a second laser beam (780 nm), and an objective lens for converging the laser beam from the light source portion onto an recording layer of the optical disc. The objective lens is provided with a transmittance controlling phase grating in a peripheral region to have a wavelength dependence such that the transmittance for the first laser beam is higher than the transmittance for the second laser beam. The transmittance controlling phase grating is formed as a plurality of concentric grooves. Each of the grooves has a rectangular cross-section in a plane containing an optical axis of the objective lens.

Abstract: An objective lens and an optical head including the objective lens for reading information contained on substrates having different thicknesses using laser beams having different wavelengths. The objective lens includes an annular phase shifter for decreasing an aberration of a focused spot of each of the laser beams. The annular phase shifter can be optimally combined with the objective lens having inner and outer regions each having a different substrate thicknesses.

Abstract: An optical disk apparatus comprises an optical pick-up unit for reproducing information on an optical disk, a first reproducer for processing an information signal obtained by the pick-up unit by one of a waveform slice method and a PRML method, and producing a first reproduction signal, a second reproducer for detecting a minimum value of a level of the information signal and producing a second reproduction signal, and a switch for selecting, as a reproduction information signal, one of the first and second reproduction signals, in accordance with a recording density of the optical disk to be reproduced.

Abstract: An optical head for an optical disc drive is provided with a first laser diode that emits a shorter wavelength laser beam, a second laser diode that emits a longer wavelength laser beam, and an objective lens for converging the beams emitted by the laser diodes on the data recording surface of the optical disc. Each of first and second surfaces of the objective lens is rotationally symmetrical, and a rotational axis of the first surface and a rotational axis of the second surface are arranged to be deviated from each other.

Abstract: An objective lens capable of recording well either CD or DVD wherein a ringed step portion 11 to 15 is provided in a first surface of the objective lens 3, the step portion 11 to 15 has function to produce a phase difference with respect to light having a first wavelength, a ringed step portion 21 to 26 is provided in a second surface of the objective lens 3, and the second step portion 21 to 26 has function to produce a phase difference with respect to light having a second wavelength.

Abstract: An objective lens converges a shorter wavelength laser beam on a DVD having a protective layer, which is 0.6 mm thick, and a longer wavelength laser beam on a CD having a protective layer, which is 1.2 mm thick. A common region is defined on the objective lens. The common region provides a numerical aperture appropriate for converging the longer wavelength laser beam on the CD. Coma of the objective lens in the first region is compensated better in a case where the longer wavelength laser beam is converged on the CD than a case where the shorter wavelength laser beam is converged on the DVD.

Abstract: An optical pickup including a light source for radiating a light beam, a diffraction element for separating a light beam radiated from the light source into at least three beams, namely a main beam and two side beams, an objective lens for converging the light beams separated by the diffraction element on a signal recording surface of the optical recording medium, a light receiving unit having a four-segment first light receiving portion for receiving the main beam reflected by the recording surface of the optical recording medium and second and third light receiving portions arranged on both sides of the first light receiving portion for receiving the side beams reflected by the recording surface of the optical recording medium, and a calculation unit for generating a first tracking signal based on respective outputs of the first light receiving portion and for generating a second tracking signal based on outputs of the second and third light receiving portions.

Abstract: An optical pickup device including an objective lens which is compatible with a plurality of optical disks of respectively different specifications, such as a digital versatile disk (DVD), a compact disk-recordable (CD-R) medium, a compact disk (CD) and a laser disk (LD). The optical pickup device includes a laser source to emit light, an objective lens to focus the light emitted from the laser source on respective information recording surfaces of a plurality of optical recording media as an optimal optical spot, and an optical detector to detect light reflected from the information recording surface of the optical recording medium on which the optical spot has been focused and transmitted through the objective lens. The objective lens includes a first lens area, a second lens area, and a third lens area to focus the light emitted from the laser source.

Abstract: An optical pickup apparatus includes a light source for emitting a light flux; and a converging optical system having a first, second, and third divided surface, which are divided in the order named from the vicinity of an optical axis of the converging optical system, for converging the light flux emitted from the light source, wherein a beam spot passing through the first and third divided surfaces is formed onto a first optical information recording medium having a transparent substrate whose thickness is t1, and a beam spot passing through the first and second surfaces is formed onto a second optical information recording medium having a transparent substrate whose thickness is t2 that is more than t1. The optical pickup apparatus further includes an image sensor for receiving a light flux reflected from the first and/or second optical information recording medium.

Abstract: There is provided an optical head including a laser diode chip, a lens for focusing lights onto an object, an optical separator for separating lights reflected from the object, from an optical axis of a light directing towards the lens from the laser diode chip, and a photodiode chip receiving lights having been separated from the optical axis by the optical separator. The optical separator is defined by first and second sidewalls, and first to fourth outer surfaces, and has first and second inner planes both being inclined relative to the first outer surface. A light enters the first outer surface, passes through the first and second inner planes, leaves the optical separator at the third outer surface, and is focused onto the object by the lens. The light having been reflected by the object enters the third outer surface, and is reflected at the second inner plane by the remaining half.

Abstract: The objective lens of the present invention includes a center portion and a periphery portion surrounding the center portion. An aberration of the periphery portion is corrected such that a light spot is formed by the convergence of a luminous flux which has been transmitted through the periphery portion and then transmitted through a first light transmissive flat plate, and an aberration of the center portion is corrected such that a light spot is formed by the convergence of a luminous flux which has been transmitted through the center portion and then transmitted through a second light transmissive flat plate which is thicker than the first light transmissive flat plate.

Abstract: Disclosed is an objective lens of an optical pick-up that includes a refractive lens and a diffractive lens structure that is formed as a large number of concentric ring areas having minute steps in an optical axis direction at the boundaries therebetween. The lens surface of the objective lens is divided into a high NA exclusive area for a DVD only, and a common area that is surrouned by the high NA exclusive area. The diffractive lens structure in the common area changes the spherical aberration in the undercorrected direction as the wavelength of the incident laser beam increases. The diffractive lens structure formed in the high NA exclusive area has a smaller wavelength dependence of a spherical aberration than that formed in the common area, and is designed such that a spherical aberration at the short wavelength is adequately corrected for the thin cover type optical disc.

Abstract: A recording/reproducing apparatus having an optical pickup device which is efficient in light use having little spherical aberration.

Abstract: A recording/reproducing apparatus having an optical pickup device which is efficient in light use having little spherical aberration.

Abstract: An objective lens and an optical head including the objective lens for reading information contained on substrates having different thicknesses using laser beams having different wavelengths. The objective lens includes an annular phase shifter for decreasing an aberration of a focused spot of each of the laser beams. The annular phase shifter can be optimally combined with the objective lens having inner and outer regions each having a different substrate thicknesses.

Abstract: An optical pickup apparatus having compatibility with a recodable compact disk (CD-R) and a digital video disk (DVD), which uses a wavelength of one of a first light beam and a second light beam according to the recording medium to be used. In the optical pickup apparatus, laser light sources emit a first light beam having a relatively shorter wavelength for the DVD and a second light beam having a longer wavelength for the CD-R, respectively. An objective lens has a predetermined focal length in accordance with the position of an information recording surface in the DVD. An optical path control unit controls the path of light beams so that the light beam emitted from one of the laser light sources is directed to the objective lens and the light output from the objective lens is directed to the optical detection unit.

Abstract: An objective lens and an optical head including the objective lens for reading information contained on substrates having different thicknesses using laser beams having different wavelengths. The objective lens includes an annular phase shifter for decreasing an aberration of a focused spot of each of the laser beams. The annular phase shifter can be optimally combined with the objective lens having inner and outer regions each having a different substrate thicknesses.