Abstract: An optical pickup device includes a light module, emitting light and receiving light reflected from a recording medium, and a solid immersion lens (SIL) member disposed in an optical path between the light module and the recording medium. The SIL has a planar surface facing the recording medium and a plurality of elliptically curved surfaces opposite the recording medium. The elliptically curved surfaces have different radii of curvature arranged symmetrical with respect to a central axis for focusing the incident light to form a tight beam spot on a recording plane of the recording medium.

Abstract: 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, and a light detector. 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 to focus light transmitted through the inner area and the outer area into a single light spot by which information can be read from the information recording surface of a relatively thin first optical recording medium and scatter light transmitted through the annular lens area located between the inner area and the outer area so that information cannot be read from the information recording surface of the first optical recording medium, during reproduction of the first optical recording medium.

Abstract: An optical pickup is compatible with at least two types of optical recording media each using light beams having different wavelengths from one another and which are used for recording and reproducing information. The optical pickup includes a first laser light source for emitting a first light beam having a relatively long wavelength, and a second laser light source for emitting a second light beam having a relatively short wavelength. A beam splitting plate transmits the first light beam and reflects the second light beam toward a collimator. The collimator collimates the light beam incident from the beam splitting plate to transmit the collimated light beam into an objective lens.

Abstract: An optical head assembly having compatibility with a recordable compact disk (CD-R) and a digital video disk (DVD) includes a stationary first optical unit and a second optical unit which moves to a position to change the target sector of an optical disk loaded in an optical disk driver on which the incident beam is irradiated by travelling between an inner circumference and an outer circumference of the loaded optical disk. The first optical unit directs an emitted first light beam having a wavelength of 635 nm for a DVD to the second optical unit and detects information contained in the first light beam redirected from the second optical unit, if the DVD is the loaded optical disk.

Abstract: An optical pickup apparatus compatible with at least two types of optical recording media, using light beams having respective different wavelengths for recording and reading information, the optical pickup apparatus including two laser light sources to emit light beams having the different wavelengths, respectively, a holographic lens, including a holographic ring, to transmittal of the light beams emitted from the laser light sources in an inner region of the holographic ring, and diffracting a specific light beam among the light beams emitted from the laser light sources in an outer region relative to the inner region, an objective lens to focus the light beams passed through the holographic ring lens on the respective information recording surfaces of the two types of the optical recording media, optical elements to alter optical paths of the light beams reflected from the information recording surfaces of the optical recording media; and two photodetectors to individually detect optical information from

Abstract: A disc discriminating method and an objective lens adopting the same, in which fast disc type discrimination and stable reproduction signal generation is performed. The method includes the steps of increasing and decreasing a focus voltage applied to an actuator of an objective lens facing a disc having an information-recorded plane to move the objective lens in a standby state at a neutral position to a focus position corresponding to the disc, detecting a movement distance value of the objectiveness from a focus signal applied to the actuator when the objective lens moves to the focus position, comparing the movement distance value with a reference value and determining the disc to be a thick disc if the movement distance value is greater than the reference value, and determining the disc to be a thin disc if the movement distance value is less than the reference value.

Abstract: An optical pickup compatible with at least two types of optical recording media using light beams having respectively different wavelengths for recording and reproducing information. In the optical pickup, a first laser light source emits a light beam having a relatively shorter wavelength. A first photodetector detects a reflected light beam with respect to the relatively shorter wavelength. An objective lens forms an annular shielding region between a near axis region of a relatively smaller radius and a far axis region of a relatively larger radius. A laser unit emits a light beam having a relatively longer wavelength, and detects only a light beam passing though the near axis region in the objective lens among reflected light beams having the relatively longer wavelength.

Abstract: A lens device which can be used as an objective lens in an optical pickup apparatus includes an objective lens provided along a light path facing a disc and having a predetermined effective diameter, and light controlling means provided along the light path for controlling the light in an intermediate region between near and far axes of an incident light beam, thus providing a simplified and inexpensive device for using discs of differing thickness in a single disc drive, by reducing the spherical aberration effect.

Abstract: An optical pickup device which can obtain a stable reproduction signal by increasing the numerical aperture of an objective lens includes an objective lens facing a disc, a light source for radiating light to the disc via the objective lens, a beam splitter provided between the light source and objective lens for directing the light reflected from the disc in a path different from that of the light travelled from the light source, a photodetector for detecting the light reflected from the disc and travelled via the beam splitter, and a diaphragm provided between the beam splitter and light source and having a predetermined numerical aperture.

Abstract: An optical pickup device which is efficient in light use having little spherical aberration. The optical pickup device of an optical pickup includes an objective lens, disposed opposite a disk, having a light passing region divided into central, intermediate and periphery regions corresponding to a near axis area, an intermediate axis area and a far axis area of incident light, where the curvature of the central and peripheral regions is optimized for a thin disk and that of the intermediate region is optimized for a thick disk; a light source irradiating light toward a disk through the objective lens; a photo detector for detecting light reflected from the disk; and a beam splitter, disposed between the objective lens and the light source, for transmitting light from the light source toward the objective lens and for diffracting light reflected from the disks toward the photo detector.

Abstract: An optical pickup device which is capable of reproducing and recording information from at least two discs having different thicknesses includes a light source, an objective lens provided along the light path from the light source facing the plane of a disc and having a predetermined effective diameter, a beam splitter provided between the objective lens and the light source, a photodetector for detecting the beam split from the light splitter and reflected from the disc, and light controller provided along the light path facing the photodetector lens for controlling the light of the intermediate region between near- and far axis regions of an incident light beam. The optical pickup device is simplified and the manufacturing cost therefor is low. Also, by reducing the spherical aberration effect for the light, discs having different thicknesses can be used in a single disc drive.

Abstract: An objective lens for reproducing/recording information from/onto discs having different thicknesses and an optical pickup device adopting the same. The objective lens device includes an objective lens provided along a light path facing a plane of a disc and having a predetermined effective diameter, and a light controller provided along the light path for controlling the light of an incident light beam between near and far axes of the objective lens, wherein the central portion of the objective lens corresponding to the near-axis region of the incident light beam has the optimum curvature and aspherical coefficient for both thick and thin discs. Therefore, the objective lens device is simplified and inexpensive. Also, the objective lens device can be used for discs of different thicknesses in a single disc drive, by reducing the spherical aberration effect.

Abstract: An optical pickup device which can obtain a stable reproduction signal by an increased numerical aperture of an objective lens. The optical pickup device includes an objective lens unit having an objective lens facing a disc and having a predetermined effective diameter and at least two auxiliary lenses provided in exterior sides of the objective lens for directing +1st-order diffracted light to a light path different from that of the light passing through the objective lens, a light source for irradiating light onto the disc through the objective lens, a light splitter interposed between the light source and the objective lens for directing the light reflected from the disc to a light path different from that from the light source, a photodetector for detecting the light reflected from the disc and transmitted via the light splitter, and at least two diffracted light detectors for detecting diffracted light incident from the auxiliary lenses.

Abstract: A lens device which can be used as an objective lens in an optical pickup apparatus includes an objective lens provided along a light path facing a disc and having a predetermined effective diameter, and light controlling means provided along the light path for controlling the light in an intermediate region between near and far axes of an incident light beam, thus providing a simplified and inexpensive device for using discs of differing thickness in a single disc drive, by reducing the spherical aberration effect.

Abstract: An optical pickup apparatus for recording and reproducing information, which is manufactured to be extremely small in a hybrid type. The optical pickup apparatus includes a first holographic optical element as a beam expander for diffracting to enlarge a diverging angle of an incident beam emitted from a light source and a second holographic optical element as an object lens for diffracting the incident beam whose diverging angle is enlarged by the first holographic optical element to focus the incident beam on an optical disk. Here, the first holographic optical element has a function of a beam splitter for diffracting a reflected beam to be separated as well as a function of a beam expander. The optical pickup apparatus is manufactured to be extremely small and ultralight due to its short optical path.

Abstract: An optical pickup device which is capable of reproducing and recording information from/onto at least two kinds of discs having different thicknesses includes a light source, an objective lens provided along the light path from the light source facing the plane of a disc and having a predetermined effective diameter, a beam splitter provided between the objective lens and the light source, and a photodetector for detecting the beam split from the light splitter and reflected from the disc, wherein the photodetector has a first detection region and a second detection region provided in the peripheral portion of the first detection region. The optical pickup device is simplified and the manufacturing cost therefor is low. Also, by reducing the spherical aberration effect for the light, discs having different thicknesses can be used for a single disc drive.

Abstract: A high density recording method for performing high density recording by reducing a light spot size in an optical pickup for recording information by scanning an optical disk with the light spot, spatially controlling the phase or the intensity of light being focused within the optical focal length of an objective lens by employing a diffraction optical element so as to form on the optical disk a light spot whose diameter is reduced according to the width of the portion for controlling the phase or intensity of the light. The distribution of the optical intensity is variable depending on the distance between the diffraction optical element and the optical disk, to thereby enable theoretically forming a limitlessly small light spot, and actually, greatly increase the recording capacity. The diffraction optical element can be used as a floating slider in an optical pickup having a swing arm.

Abstract: A reproducing/recording optical pickup compatible with discs having different thicknesses includes a transparent plate having a central portion formed with a diffraction grating pattern for diffracting the light travelling from the light source to the objective lens, and a transparent portion through which the light passes, and a photodetector having first and second light receiving portions. The zero-order transmitted light and the passing light are focused using all regions of the aperture of the objective lens with respect to a thin disc. The positive first-order diffracted light diffracted by the diffraction grating pattern of the transparent plate is focused onto a thick disc by partial regions of the objective lens. Then, the reflected lights thereof are detected by the first and second light receiving portions, respectively.

Abstract: An optical pickup apparatus which can reduce effective size of an optical spot focused on an optical recording medium is provided. The optical pickup apparatus, in which a light beam emitted from a light source is focused on an optical medium for recording a signal on the optical medium and reproducing the signal from the optical medium, includes an objective lens for focusing the light beam on the surface of the optical medium and focusing a beam reflected from the surface of the optical medium, and two or more wave plates each having a different optical axis direction and located on an optical path between the light source and the objective lens. As a result, the spot size and the intensity of a first side lobe can be decreased, and the spot size can be adjusted according to the recording and reproducing modes.

Abstract: A dual-focus objective lens for an optical pickup which is compatible with both 0.6 mm and 1.2 mm disks is compensated in its aberration with respect to a light spot on a recording plane of the loaded disk and at least one of a light-receiving plane and a light-emitting plane of the dual focus objective lens has a first curvature unit and a second curvature unit whose curvature radii are different from each other. Incident light beams passing through the whole region of the first curvature unit and second curvature unit are focused onto the thinner disk, and parts of incident light beams passing through the region around the first curvature unit are focused onto the thicker disk. In the optical pickup having the dual focus objective lens, since the light is not divided, light efficiency is improved, thereby reproducing a signal with a high signal-to-noise ratio. Particularly, an optical pickup enabling recording as well as reproduction is obtained.