Sony Corporation

Kiyoshi Ohsato

Toshio Watanabe

Isao Ichimura

Fumisada Maeda

Kenji Yamamoto

Atsushi Fukumoto

Akira Suzuki

Tatsuya Narahara

Yoshiteru Kamatani

Kamon Uemura

Seiji Kobayashi

Tadashi Ozue

Akio Yamakawa

Masamichi Utsumi

Hiroshi Miyoshi

Yasushi Fujinami

Tamotsu Yamagami

Takashi Nakao

Shunji Yoshimura

Toshiyuki Kashiwagi

Shigeo Kubota

Michio Oka

Yoshiyuki Akiyama

Hitoshi Okada

Hisashi Masuda

Tetsuhiro Sakamoto

Naoya Eguchi

Mikio Sugiki

Fumiaki Henmi

Toshiki Udagawa

Teruaki Higashihara

Shinichiro Kuwabara

Shinji Katsuramoto

Yasunori Terayama

Yoji Ishii

An optical disc recording/reproduction apparatus for recording and/or reproducing a data by applying a beam from an optical head unit through a substrate onto/from a recording layer of the optical disc through, wherein the substrate of the optical disc is 0.3 mm or below; the optical head unit comprises: an objective lens for converging an incident beam and emitting the beam toward the optical disc; a forward lens for converging the beam introduced through the objective lens and applying the beam to the optical disc; a lens holder where the objective lens and the forward lens are fixed; and an actuator for driving the objective lens and the forward lens as a unitary block and controlling at least focusing, the objective lens and the forward lens having a total numerical aperture of 0.8 or above.

Optical disc recording/reproduction apparatus and method

An optical head comprising an objective lens having a large numerical aperture of 0.8 or more. The head further comprises a light source and an aberration-correcting lens group. To correct spherical aberration due to the manufacturing errors of an optical recording medium and lenses, to sufficiently correct chromatic aberration due to the use of a short-wavelength semiconductor laser and to correct aberration resulting from the use of the same optical system for light beams of different wavelengths, the objective lens is composed of two more lenses and has a numerical aperture of 0.80 or more and the aberration-correcting lens group is composed of a positive lens group and a negative lens group . The space between the positive lens group and negative lens group of the aberration-correcting lens group is changed, thereby to correct spherical aberration occurring at each optical surface of the optical system.

Optical head and recording/reproducing device

A focus controller for focusing a light beam and positioning the focused light beam onto a signal recording layer of a signal recording media is disclosed. The controller comprises a light beam focusing means having a numerical aperture of 0.6 or more; a focus controlling means for positioning the light beam focused by the light beam focusing means onto the signal recording layer of the recording media; and an offset adjusting means for adjusting an offset between the focused light beam positioned by the focus controlling means and the signal recording layer of the recording media. The controller positions the light beam focused by an objective lens onto the signal recording layer of a recording media; moves the objective lens within a predetermined optical-axial range, detects an amplitude of a signal read from the recording media at either end of the optical-axial range, and adjusts an offset between the focused light beam positioned by the objective lens and the signal recording layer, depending on a difference between the amplitudes of the detected reproduced signal.

Focus controlling apparatus and method, and optical disc drive

A recording/reproducing apparatus for an optical recording medium in which a laser light beam is illuminated on an optical recording medium using a double-lens type objective lens made up of at least a first lens and a second lens to record and/or reproduce the information. The apparatus includes a first lens for converging the laser light illuminated from a light source, a second lens arranged between the first lens and the optical recording medium and a voice coil motor for causing relative movement of the first and second lenses for varying the distance therebetween in the direction along the optical axis. The first lens is moved to vary the distance between the first and second lenses. This enlarges the numerical aperture and diminishes the effect of aberration to enable high-density recording and/or reproduction of information signals to a high recording density.

Lens driving device, optical head and optical disc system

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.

Optical pickup for discriminating between and reading different types of optical discs

The present invention provides an optical recording medium including a recording layer and a light-transmitting layer successively formed on one side of a substrate, so that a light is applied from the side of this light-transmitting layer for performing an information recording and/or reproduction. On the opposite side of the substrate not having the light-transmitting layer, a water-proof film consisting of at least one layer is formed. This suppresses the skew, enabling to improve the information recording and/or reproduction characteristics for a higher recording density. Furthermore, if the light-transmitting layer has a thickness t&equals;3 to 177 micrometers in an information signal section of the recording medium, and a thickness fluctuation &Dgr;t &lE;&plusmn;5.26 (&lgr;/NA ) micrometers (wherein NA is a numerical aperture and &lgr; is a wavelength of the recording/reproduction optical system), it is possible to realize a high NA and a high capacity.

Optical recording medium and optical disk device

The present invention provides an optical disc recording/reproduction apparatus and method capable of carrying out an accurate recording or reproduction when using a lens unit consisting of at least two lenses, which comprises: first drive means for driving both of the first lenses and the second lens in a focusing direction; second drive means for relatively driving the second lens with respect to the first lens in the focusing direction; focus servo means for carrying out focus servo by driving the first drive means so as to drive both of the first lens and the second lens in the focusing direction; and jog mode adjustment means for driving the second drive means after the focus servo is locked, so as to carry out a jog mode adjustment of the position of the second lens with respect to the first lens.

Optical disc recording/reproduction apparatus having a lens group, focus, servo, and jog mode adjustment

An optical pickup device for improving the numerical aperture of an objective lens and for assuring high-reliability recording/reproduction of information signals. The optical pickup device has a first lens 6 having a curvilinear or planar surface facing an optical recording medium 5 and having the numerical aperture set to a pre-set value, and a second lens 3 arranged for clamping the first lens 6 between t and the optical recording medium 5. The optical pickup device also has a light-converging optical system for converging the reflected light from the surface of the optical recording medium 5 and a first movement unit 2 for moving the first objective lens 6 and the second lens 3 along the direction of the optical axis with respect to the second objective lens 3. The optical pickup device also has a second movement unit 11 for moving the first objective lens 6 along the direction of the optical axis relative to the second objective lens 3 and a fixation unit 12 for fixing the first objective lens 6 moved by the second movement unit 9. The method for adjusting the optical processing device includes a step of adjusting the position along the optical axis of the first objective lens 6 and a step of fixing the position of the first lens 6.

Optical pick-up device, optical recording/reproducing apparatus and

The present invention provides an objective lens unit which can be simultaneously adjusted to an NA specification and a substrate thickness of an optical recording medium. The objective lens unit for applying a beam to an optical recording medium so as to read and/or record from/to the optical recording medium includes: a first lens; a second lens; a cylindrical frame for movably supporting the second lens with respect to the first lens in a direction of an optical axis; and diaphragm means provided in the vicinity of the second lens and movable together with the second lens in the direction of the optical axis, for shading a part of the beam to be applied to the optical recording medium. The present invention also provides a recording/reproduction apparatus having the aforementioned objective lens unit, enabling to preferably write and read a data signal into/from an optical recording medium of different specifications.

Objective lens unit and recording/reproduction apparatus

A recording/reproducing apparatus for an optical recording medium which is used for recording and/or reproducing information on/from the optical recording medium by irradiating the optical recording medium with a laser light using two-group objective lenses comprising at least two lenses as the first and second lenses, is provided so as to comprise a light source emitting the laser light, the first lens for focusing the laser light emitted from the light source, the second lens arranged between the first lens and the optical recording medium, and a device for moving both the first and second lenses relative to each other to change the distance between them in the optical axis direction of the laser beam, so that the moving device moves the second lens to change the distance between the first and second lenses. Consequently, this invention can provide the recording/reproducing apparatus with a larger numerical aperture (NA) and reduce the influence of spherical aberration on the light beam to realize high density recording/reproducing of information signals.

Recording/reproducing apparatus and recording/reproducing method for

An objective lens having a doublet structure and a number of apertures of 0.7 or more and an optical pickup apparatus having the objective lens to be adaptable to a optical recording medium having a high information recording density, the objective lens being structured such that at least one side is formed into a aspheric surface and the lens elements are made of low-diffusion glass having an Abbe's number of 40 or greater.

Objective lens having a doublet lens with high numerical aperture

This invention intends to provide an optical pickup of which it is possible to limit aberrations within a tolerable limit without incorporating a special device for that purpose even if errors arise in thickness of component lenses of a two-lens system constituting an element of the pickup. This object is achieved by providing an optical pickup incorporating a two-lens system with first and second lenses 13 and 14 being arranged in the following manner: the first lens has a first surface 15 to receive a laser beam radiated from a semiconductor laser and a second surface 16 to direct the laser beam transmitted from the first surface 15 towards the second lens 14; the second lens 14 has a third surface 17 to receive the light flux transmitted from the second surface 16 and a fourth surface 18 to direct the light flux transmitted from the third surface 17 towards an optical disc placed opposite thereto; and the first and fourth surfaces are used as a reference during positioning.

Optical pickup and an optical pickup objective lense assembling method

An optical recording medium recording and reproducing apparatus for recording information on an optical recording medium and/or reproducing information therefrom by irradiating the optical recording medium with laser light by the use of a two-group objective lens composed of at least first and second lenses. This apparatus is provided with: a light source for emitting laser light; a first lens for converging laser light emitted from the light source; a second lens interposed between the first lens and the optical recording medium; a detecting unit for detecting a kind of the recording medium; and a movement unit for changing the distance in the direction of an optical axis between the first and second lenses by causing a relative movement between the first and second lenses. Further, the distance between the first and second lenses is changed by the movement unit, which causes the second lens to move, according to a result of a detection, which is performed by the detecting unit. Thereby, the numerical aperture NA of the objective lens is increased. Moreover, the influence of aberration is mitigated. Consequently, the high-density recording and reproducing of information signals can be achieved.

Growing community of inventors

Chiba, Japan

Kiyoshi Ohsato