Abstract: 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 20 is composed of two more lenses and has a numerical aperture of 0.80 or more and the aberration-correcting lens group 1 is composed of a positive lens group 3 and a negative lens group 2. The space between the positive lens group 3 and negative lens group 2 of the aberration-correcting lens group 1 is changed, thereby to correct spherical aberration occurring at each optical surface of the optical system.

Abstract: 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.

Abstract: 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.

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: 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=3 to 177 micrometers in an information signal section of the recording medium, and a thickness fluctuation &Dgr;t ≦±5.26 (&lgr;/NA4) 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.

Abstract: 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.

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 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 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: A device for recording/reproducing a digital pattern as a sound track of a cinefilm is disclosed. The device includes a cinefilm 1 having an image recording area 2 in which an image is recorded, a perforation section 3 for film feed and digital pattern data recording areas 5 and 6 provided in the vicinity of the perforation section 3. Plural channels of audio data are recorded as the digital patterns in the digital pattern data recording areas.

Abstract: A method for designing an objective lens apparatus formed by at least two lenses, a first lens and a second lens, which includes the steps of: measuring aberration which occurs when a light beam is converged by the first lens; setting the first lens is set such that the aberration occurring in the first lens satisfies Marechal's criterion, in accordance with the measurement results; measuring aberration which occurs when a light beam is converged by the first lens and the second lens; and setting the second lens such that the aberrations occurring in the first lens and the second lens satisfy Marechal's criterion, in accordance with the measurement results. Accordingly, an objective lens apparatus with a small aberration and a large numerical aperture NA can be designed by this method.

Abstract: An optical pickup device for condensing the light from a light source on a signal recording surface of an optical recording medium, such as an optical disc. A semi-spherical lens of the optical pickup device has a surface 9b facing an optical disc 20 and has a pre-set refractive index. The optical pickup device also has a slider 12 adapted for securing the lens 9 and for being in sliding contact with an optical disc 20, and a spring plate 13 adapted for thrusting and supporting the slider in sliding contact with the optical disc 20. With the optical pickup device, high density reproduction may be realized, while the tolerance value for warping during disc molding or the tolerance value for warping due to moisture absorption may be increased. In addition, the production yield and the degree of freedom in selecting the disc materials may be improved.

Abstract: An optical pickup device for condensing the light from a light source on a signal recording surface of an optical recording medium, such as an optical disc. A semi-spherical lens of the optical pickup device has a surface 9b facing an optical disc 20 and has a pre-set refractive index. The optical pickup device also has a slider 12 adapted for securing the lens 9 and for being in sliding contact with an optical disc 20, and a spring plate 13 adapted for thrusting and supporting the slider in sliding contact with the optical disc 20. With the optical pickup device, high density reproduction may be realized, while the tolerance value for warping during disc molding or the tolerance value for warping due to moisture absorption may be increased. In addition, the production yield and the degree of freedom in selecting the disc materials may be improved.

Abstract: 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.