Abstract: An optical-pickup hologram element has six regions on an x-y plane, divided as follows: the first region with a first line (an x-axis) and a second line that connects points (?xa, 0) and (?xb, yb); the second region with the first and second lines and a third line connecting points (xa, 0) and (xb, yb); the third region with the first and third lines; the fourth region with the first line and a fourth line connecting the point (xa, 0) and a point (xb, ?yb); the fifth region with the first and fourth lines and a fifth line connecting the point (?xa, 0) and a point (?xb, ?yb); and the sixth region with the first and fifth lines (xa<xb and ?xb<?xa). The second and fifth, and the other regions are given astigmatism at different angles to the second line.

Abstract: In a photo pickup device, an incident area 30 for a reflection light of a light spot is divided into four areas 30a˜30d by parting lines 31, 32 making axial-symmetrical angles with a direction Y of a projected track on an optical disc. In these areas, the so-divided areas 30a, 30c are formed so as to diffract the light in one or more directions in a range of 90 degrees±20 degrees to the direction Y and impress misalignment on each diffraction light. In each diffraction light, two focal lines produced due to the astigmatism make approx. 45 degrees with the direction Y of the projected track. Further, the divided areas 30b, 30d are characterized by diffracting the light in one or more directions in a range of 90 degrees±20 degrees to the direction Y.

Abstract: An optical-pickup hologram element has six regions on an x-y plane, divided as follows: the first region with a first line (an x-axis) and a second line that connects points (?xa, 0) and (?xb, yb); the second region with the first and second lines and a third line connecting points (xa, 0) and (xb, yb); the third region with the first and third lines; the fourth region with the first line and a fourth line connecting the point (xa, 0) and a point (xb, ?yb); the fifth region with the first and fourth lines and a fifth line connecting the point (?xa, 0) and a point (?xb, ?yb); and the sixth region with the first and fifth lines (xa<xb and ?xb<?xa). The second and fifth, and the other regions are given astigmatism at different angles to the second line.

Abstract: In a photo pickup device, an incident area 30 for a reflection light of a light spot is divided into four areas 30a˜30d by parting lines 31, 32 making axial-symmetrical angles with a direction Y of a projected track on an optical disc. In these areas, the so-divided areas 30a, 30c are formed so as to diffract the light in one or more directions in a range of 90 degrees ±20 degrees to the direction Y and impress misalignment on each diffraction light. In each diffraction light, two focal lines produced due to the astigmatism make approx. 45 degrees with the direction Y of the projected track. Further, the divided areas 30b, 30d are characterized by diffracting the light in one or more directions in a range of 90 degrees ±20 degrees to the direction Y.

Abstract: Astigmatism and coma are suppressed in an optical pickup device such that light from a single real laser light source is diffracted and divided by a hologram module into a plurality of light spots which are focused upon a plurality of tracks of an optical disk to read data on the tracks at the same time. A non-diffraction end of fraction hologram patterns of the hologram module are determined so that light diffracted by the hologram module is given inverse aberration of that to be caused by optical elements in optical path from the real laser light source to the optical disk. Another hologram pattern provides a uniform intensity of a light spot formed of a laser light by an optical element.

Abstract: A reproducing apparatus compatible with both CD and MD. First and second cartridge holding members are rotatably supported by a cover unit between a position where MD is held on a turntable and a position where the holding members are retracted not to contact CD held between the turntable and a clamper. The clamper is movable between a position where CD is clamped to the turntable and a position where the clamper is retracted not to contact MD held on the turntable. An optical pickup movably supported by a main unit reproduces both CD and MD.

Abstract: CDs and MDs are recorded/reproduced by using the same disk motor and optical pickup so that the cost and space of the recording/reproducing apparatus can be reduced. Shafts formed upright on the clamper arm for supporting a clamper are inserted into bifurcated prolong holes of main sliders and L-character shaped prolong holes of main side plates, and are biased by springs. A holder for holding an MD cartridge moves as a subsidiary slider is moved backward so that the MD can be attracted to a turntable. When the main slider is moved forward, the clamper arm is moved backward and is not allowed to move downward. A CD is transported onto the turntable by a loading roller. As the main slider moves forward thereafter, the clamper arm 7 lowers to clamp the CD.

Abstract: An optical disk holding apparatus suitable for holding either an optical disk of a first type, such as a compact disk, or an optical disk of a second type, such as a mini disk. The optical disk holding apparatus operates to hold each disk such that a distance between an optical pick-up and a first surface of the optical disk is the same when the apparatus is holding an optical disk of the first type or an optical disk of the second type. The optical disk holding apparatus includes a fixed unit mounted on a rotary shaft of a disk motor and a movable unit that is guided by the fixed unit and biased upward by a spring. A magnet is mounted on the upper surface of the fixed unit for attracting one of a clamper and a metal plate of a mini disk. When holding a disk of a first type, such as a compact disk, a tapered surface of the movable unit engages the center hole of the compact disk.