Tdk Corporation

Mitsuru Kinouchi

Noriyuki Kawano

Yoshio Saito

Kouichi Ogura

Hiroyuki Matsuura

Nobuo Uekusa

Kazunori Hirose

An optical pickup comprises an objective-lens driving device including a movable section provided with an objective lens, a focusing coil, and tracking coils, and a fixed section provided with a single magnetic circuit having a magnetic gap, the focusing coil and the tracking coils being disposed in the magnetic gap. The point of application of a tracking-driving force, the point of application of a result force of focusing-driving forces occurring in and outside the magnetic gap, and the position of the center of gravity of the movable section are made to substantially coincide with each other. In addition, the objective lens and the magnetic circuit are disposed within an area of a window in a lower shell of a optical disk. Further, a through hole for accommodating a lower portion of a yoke of the magnetic circuit is provided in a mounting base on which the objective-lens driving device is mounted. An inclining fulcrum and a height adjusting means for inclining the objective-lens driving device about the inclining fulcrum are provided in the vicinities of the through hole.

Optical pickup

Magneto-optical recording/reproducing pickup head with a diffraction grating and a wollaston prism

An optical pickup includes an objective-lens driving device including a movable section provided with an objective lens, a focusing coil, and tracking coils, and a fixed section provided with a single magnetic circuit having a magnetic gap, the focusing coil and the tracking coils being disposed in the magnetic gap. The point of application of a tracking-driving force, the point of application of a result force of focusing-driving forces occurring in and outside the magnetic gap, and the position of the center of gravity of the movable section are made to substantially coincide with each other. In addition, the objective lens and the magnetic circuit are disposed within an area of a window in a lower shell of a optical disk. Further, a through hole for accommodating a lower portion of a yoke of the magnetic circuit is provided in a mounting base on which the objective-lens driving device is mounted. An inclining fulcrum and a height adjusting means for inclining the objective-lens driving device about the inclining fulcrum are provided in the vicinities of the through hole.

Optical pickup with a compact design

An optical pickup comprises an objective-lens driving device including a movable section provided with an objective lens, a focusing coil, and tracking coils, and a fixed section provided with a single magnetic circuit having a magnetic gap, the focusing coil and the tracking coils being disposed in the magnetic gap. The point of application of a tracking-driving force, the point of application of a result force of focusing-driving forces occurring in and outside the magnetic gap, and the position of the center of gravity of the movable section are made to substantially coincide with each other. In addition, the objective lens and the magnetic circuit are disposed within an area of a window in a lower shell of a optical disk. Further, a through hole for accommodating a lower portion of a yoke of the magnetic circuit is provided in a mounting base on which the objective-lens driving device is mounted. An inclining fulcrum and a height adjusting component for inclining the objective-lens driving device about the inclining fulcrum are provided in the vicinities of the through hole.

A light source for generating light beams, a diffraction grating for splitting the light beam emitted from the light source into at least three light beams, and an objective lens for receiving the reflecting light beams from the recording medium, the magnification of the objective lens being -6.0 to -12.0, make up a collimatorless optical system. The reflecting light beams emanating from the objective lens are split by a beam splitter, these split light beams are each split into at least three light beams by a Wollaston prism, and are incident on a photo detecting element. A tracking error signal, a focusing error signal, and a magneto-optical signal are generated using the light beams received by the photo detecting element. The beam splitter and the Wollaston prism may be substituted by a multifunctional Wollaston prism. If the nine split light beams are all received by the photo detecting element, the signals produced by the photo detecting element are large in amplitude.

Growing community of inventors

Tokyo, Japan

Mitsuru Kinouchi