Samsung Electronics Co., Ltd.

Hea-jung Suh

Chong-sam Chung

Young-man Ahn

Tae-kyung Kim

Tae-Kyung Kim

In-sik Park

Young-Man Ahn

Tatsuhiro Otsuka

Byoung-ho Choi

Seong-sin Joo

Byung-in Ma

Jong-bae Kim

Chul-woo Lee

Jong-Chul Choi

Jin-Won Lee

Kwang Hyun Kim

Seok-jung Kim

Seung-tae Jung

Dong-ho Shin

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.

Optical pickup device having chromatic aberration correction lens

An optical pickup apparatus including a swing arm pivotably installed in a tracking direction with respect to a disc, and an optical pickup unit supported by the swing arm and driven in a focusing direction, wherein the optical pickup unit includes a laser diode, an objective lens to focus light emitted from the laser diode on a recording surface of the disc, and a heat sink plate to dissipate heat generated from the laser diode, wherein the heat sink plate is provided close to the disc so as to be directly exposed to wind generated during rotation of the disc.

Optical pickup apparatus

A method of and a circuit for providing a playback signal, which is compensated for time delay, from a photodetector having a plurality of outputs. A time difference between a first signal corresponding to a part of the outputs of the photodetector and a second signal corresponding to another part of the outputs of the photodetector is detected and one of the first and second signals is temporally shifted to compensate for a time delay between different outputs of the photodetector. The temporally shifted signal is summed with the other signal to provide a playback signal. Accordingly, the time delay between the outputs of the photodetector is compensated, thereby increasing the degree of modulation of the data playback signal. In addition, distortion or degradation of the signal is suppressed and occurrence of errors in the playback signal is minimized, thereby improving the reliability of the playback signal.

Method and circuit for detecting playback signal which is compensated for time delay

An optical pickup capable of effectively reducing chromatic aberration that includes a collimating lens, which includes a diverging lens with diverging power and a focusing lens with focusing power, arranged on the optical path between a light source and an objective lens, wherein assuming that the total focal length of the collimating lens is f and the focal length of the diverging lens is fn, the collimating lens satisfies the relationship &#x2212;1.5&#x3e;f/fn. The optical pickup is compatible with both existing digital versatile disks (DVDs), and high-definition (HD)-DVDs, which will not yet standardized, need a blue light source near 405 nm and an objective lens having an numerical aperture of 0.6 or more.

Optical pickup with improved collimating lens for use with long and short wavelength laser beams

An optical pickup apparatus for compensating for the deviation in the thickness of the optical disk and method therefor. The optical pickup includes a light source which emits light, an optical path changer which changes a proceeding path of incident light, an objective lens which focuses incident light to form a light spot on an optical disk, a light splitter, provided on the optical path between the light source and the optical path changer, which splits incident light into at least two light beams including first and second light beams so that at least two light spots including a main light spot having no aberration and an auxiliary light spot having a predetermined spherical aberration are formed on the optical disk, a photodetector including first and second light receiving portions which respectively receive the first and second incident light beams reflected by the optical disk and passing through the optical path changer, and a signal processing portion, including a delay which delays the phase of a second signal in order to synchronize a first signal and the second signal which are detected and optoelectrically converted by the first and second light receiving portions, to compensate for the deviation in the thickness of the optical disk.

Optical pickup apparatus having disk thickness deviation correction and method therefor

A method and circuit for providing a playback signal which is compensated for time delay. The circuit includes a time delay compensator for detecting a time difference between outputs of a photodetector and temporally matching part of the outputs of the photodetector and another part of the outputs of the photodetector, between which the time difference occurs, to compensate for time delay between different outputs of the photodetector, and an operational unit for summing the part of the outputs of the photodetector, which is compensated for the time delay, and the other part of the outputs of the photodetector to provide a playback signal. Accordingly, the circuit compensates for the time delay between the outputs of the photodetector, thereby increasing the degree of modulation of the data playback signal. In addition, the circuit maximumly suppresses the distortion or degradation of the signal and minimizes the occurrence of errors in the playback signal, thereby improving the reliability of the playback signal.

An optical pickup includes an aberration correction element to correct chromatic aberration caused by variation of power from a light source when changing between operating modes in a recording medium. The aberration correction includes a first retardation member, which includes a stepped convex pattern with a plurality of steps at one side, and a second retardation member combined with the first retardation member. The second retardation member includes a stepped concave pattern with a plurality of steps at one side facing the first retardation member, the stepped concave pattern corresponding to the stepped convex pattern. The first and the second retardation members include different refractive indices for a light beam, which allows the first and the second retardation members to selectively create a phase difference of an incident light beam according to a polarization of the incident light beam.

Aberration correction element and optical pickup adopting the same

Optical pickup for and method of correcting aberration due to thickness variations of optical media

An objective lens device and an optical pickup employing the objective lens device. The objective lens device is formed of three lenses including a lens having a negative power and formed of material having an Abbe number which is 45 or less in line d. At least one surface of surfaces of the three lenses is formed to be aspherical. Thus, in the objective lens device, a high numerical aperture of 0.70 or more is realized and chromatic aberration is corrected with respect to blue light enabling improved recording and/or reproduction using blue light.

Objective lens device for correcting chromatic aberration and optical pickup employing the same

An optical pickup capable of focusing a main light spot and an auxiliary light spot including optical aberration when an optical disk is not tilted, and analyzing the main light spot and the auxiliary light spot with a photodetector, thereby correcting aberration. The optical pickup includes a light source emitting light; light splitting means for splitting an incident beam into at least two light beams including a first beam and a second beam so as to form at least two light spots on an optical disk; optical path changing means for changing the traveling path of the incident first and second beams; an objective lens focusing the first and second beams to form a main light spot and an auxiliary light spot, respectively, on the optical disk; a photodetector having first and second light receiving portions receiving the first and second beams reflecting from the optical disk and passing through the optical path changing means, respectively, and performing photoelectric conversion on the received beams to produce and detect electrical signals; and a signal processor correcting aberration caused by tilting of the optical disk, using the electrical signals.

Optical pickup for improving properties of a reproduction signal

A spherical aberration compensator for compensating for spherical aberration resulting from a thickness deviation of a recording medium. The spherical aberration compensator includes a central compensation which provides a phase distribution that is effective for compensating for spherical aberration resulting from the thickness deviation and a peripheral compensation portion which surrounds the central compensation portion and provides a phase distribution that is effective for reducing a worsening of the spherical aberration caused by axial displacement of an objective lens from the central compensation portion. The spherical aberration compensator effectively relieves an optical pickup having an objective lens of an NA of 0.7 or greater of worsening of the spherical aberration resulting from thickness deviation of the recording medium.

Spherical abberation compensator and optical pickup using the same

An objective lens includes an aspherical lens facing a disk and having a predetermined first focal distance and a predetermined numerical aperture, and a holographic lens installed adjacent to the aspherical lens and having a second focal distance longer than that of the first focal distance and having a diffraction lattice to compensate for the chromatism due to a change in wavelength of laser light having a wavelength of 670 nm or less. Thus, during the shift between recoding and reproduction of a DVD or an HD-DVD, the change in wavelength due to the change in power of the laser light and chromatism according to the change can be effectively corrected. Also, since the objective lens is formed of one aspherical lens and one holographic lens, the material for each of the lenses can be easily selected and also the structure of the optical pickup using the objective lens according to the present invention can be simplified.

Objective lens and optical pickup device using the same

A land/groove discriminating method and an optical recording and/or reproducing apparatus employing the method are provided. The land/groove discriminating method emits a light beam onto an optical disc having lands and grooves through an optical element capable of causing and varying an effect of thickness variation of the optical disc, detects a light beam reflected/diffracted from the optical disc by dividing the reflected/diffracted light beam into inner and outer light beam portions, and discriminates between a land and a groove of the optical disc by detecting variation in a difference signal between detection signals from the inner and outer light beam portions while varying the degree of the effect of thickness variation of the optical disc by driving the optical element.

Growing community of inventors

Seongnam, South Korea

Hea-jung Suh