Hitachi Media Electronics Co., Ltd.

Other

Hitachi, Ltd.

Hitachi-Lg Data Storage, Inc.

Hitachi Consumer Electronics Co., Ltd.

Seiichi Kato

Katsuhiko Kimura

Yoshihiro Sato

Hidenao Saito

Jun Hato

Takahiro Yamaguchi

Yoshiaki Yamauchi

Yoshiro Konishi

Ryuichiro Mizuno

Satoshi Shinada

Michio Miura

Takayuki Watanabe

Naruo Watanabe

Manabu Ochi

Shinya Fujimori

Nobuyuki Maki

Akio Yabe

Tatsuya Yamasaki

Yasushi Kinoshita

Kazumi Takahashi

Mitsuo Satake

Hiroyasu Yoshida

Teppei Tanaka

Rika Nomura

Nobuyuki Maeda

Kazuhiro Todori

Masahiko Kamesawa

Fumihito Ichikawa

Yusuke Imada

Isamu Hiroe

Masahiro Tanino

Tomoyuki Higuchi

An optical module including a plurality of laser diodes and outputting optical beams emitted from the laser diodes includes a radiator unit for radiating heat and a case enclosing the optical module. The case has a first attachment surface to which a red laser diode is attached, a second attachment surface to which a green laser diode is attached, and a corner part where the first and second attachment surfaces intersect with each other. The optical module has a first attachment part, for connecting the case to the radiator unit, in the vicinity of the corner part.

Optical module and scan-type image projection display device

High-performance and reliable objective lens driving apparatus and optical pickup wherein the tilt of an objective lens relative to an optical disc is suppressed are provided. The optical pickup is equipped with a semiconductor laser, an electro-optic component, and the objective lens driving apparatus. In this optical pickup, the objective lens driving apparatus is comprised of: a moving part including an objective lens, a holder that holds the objective lens, a focusing coil, and a tracking coil; a holding member for elastic support members that couples together multiple elastic support members providing elastic support on a fixed part and the moving part and is mounted on the moving part; the elastic support members that elastically support the moving part from the fixed part; and the fixed part. The holding member for elastic support members mounted on the moving part and the holder that holds the objective lens are joined together by fitting together a concavity and a convexity.

Objective lens driving apparatus, optical pickup

In an optical pickup equipped with a semiconductor laser, electro-optical components such as a lens, and an objective lens drive device, the objective lens drive device includes objective lenses, a holder holding the objective lenses, a focusing coil, and tracking coils. The focusing coil is wound in parallel to the optical surface of the objective lens, and formed in a parallelogram shape having inclined portions provided near the tracking coils. The two tracking coils are placed on diagonal portions of the lens holder.

Objective lens drive device and optical pickup

An objective lens actuator, for driving an objective lensfor focusing lights upon a recoding surface of an optical disc, comprises a moving part, which comprises the objective lensand a coil; a magnet, which is fixed on a yoke and drives the moving part; a plural number of elastic support parts, each of which supports the moving partat an end thereof; a first fixing portionand a second fixing portion, which fix other ends of the plural number of elastic support partsand are disposed opposite to each other in a focus direction; and a moving mechanism, which is provided on the first and second fixing portionand, so that the first and second fixing portionsandcan move in the focus direction, relatively, and thereby providing the objective lens actuatorenabling to reduce the dynamic relative tilt between the optical disc and the objective lens(i.e., reducing the tilt of the objective lensin the tangential direction when operating), as well as, an optical pickup and an optical disc drive.

Objective lens actuator for enabling to reduce the dynamic tilt between optical disc and objective lens

An optical pickup, mounting a lens actuatorthereon, the lens actuator comprises: a lenshaving an optical axis in direction in parallel with an optical disc; a holderwhich holds the lens thereon; a first guide shaftholding the holder, so as to regulate the holder to change a position thereof, into an inner surface direction of a surface having the optical axis of the lens as a normal line vector thereof; a second guide shaftwhich regulates the holder to change the position thereof, into a normal line vector of an optical disc; and a reed screw, which moves the holder into direction of the optical axis of the lens, wherein a distance between the optical axis of the lens and the optical disc, a distance between a central axis of the first guide shaft and the optical disc, and a distance between a central axis of the second guide shaft and the optical disc are lager than a distance between a central axis of the reed screw and the optical disc.

Lens driving mechanism for optical pickup and optical disc apparatus

An objective lens actuator, being suitable for a thin-sized optical pickup and a thin-sized optical disc apparatus, comprises: an objective lens for focusing a light upon a recording surface of an optical disc; and a driving mechanism including a focusing coil, tracking coils, and a magnetic circuit, for operating the objective lens into a focusing direction of approaching/receding to/from the optical disc, and into a tracking direction of a radius of the optical disc, wherein the magnetic circuit has a first magnet and a second magnet putting the objective lens therebetween, and one of the magnets is short of length in the focusing direction and is long in length in the tracking direction, comparing to the other magnet, thereby bringing an unnecessary moment, which is applied upon a moving part including the objective lens therein, to be small, and suppressing inclination or tilt and vibration of the objective lens.

Objective lens actuator and a thin-sized optical pickup with magnetic circuit having different lengthed magnets

An optical pickup device includes a hosing having three walls connected together whose horizontal cross-section is substantially U-shaped. A first wall supports one end of a shaft, a second wall facing the first wall supports the other end of the shaft and a third wall connects the first and second walls. A lubricant tray is surrounded by the three walls and the shaft. By the shaft being attached to an end side surface of the lubricant tray, the shaft can be integrally formed with the housing. A radius of curvature or an angle formed on a horizontal cross-section of the three walls is larger than a radius of curvature or an angle formed between one of the three walls and the lubricant tray.

Optical pickup device

In a disc driving apparatus, wherein a laser diode and a laser driver circuit board are mounted on a pickup housing in thermal contact therewith and are disposed adjacent to each other, a heat separation member is provided between the laser diode and the laser driver circuit board for effecting thermal separation therebetween, thereby reducing the thermal interference between the heat-generating elements that are adjacent to each other in the optical pickup. This makes it possible to protect the heat-generating elements from being deteriorated, leading to a reduction in the lifetime thereof, as well as, to improve the reliability thereof.

Disc driving apparatus

According to the invention, techniques for minimizing power consumption in optical disk drives. Embodiments according to the present invention can provide disk drives with optimal positioning of a fixing part of an objective lens driving unit incorporated therein. Spatial location of magnets can also be determined in order to reduce the power consumption and the torsion of the lens.

Disk drive apparatus having improved power consumption

In a background-art optical disk drive, it is necessary to improve acceleration generated in an objective lens driving device in order to make an objective lens track a disk rotating at a high speed. This can be achieved either by increasing a thrust force acting on a movable body including the objective lens or by making the movable body lighter in weight. One method for increasing the thrust force is to make permanent magnets larger or use permanent magnets having a large magnetic force. However, this leads to such a problem that the unit becomes larger in size or higher in cost. In order to solve the foregoing problem, an inner yoke is disposed around a beam of light and inside the movable body of the objective lens driving device. Alternatively, an inner yoke having at least two sides substantially parallel with the radial direction of the disk and at least two sides substantially perpendicular thereto is disposed inside the movable body.

Objective lens driving device and optical disk unit

In an optical disk drive using as a light source a semiconductor laser having a main electrode and a plurality of subsidiary electrodes, a wave front of a generated laser beam is modulated by controlling injection currents to the plurality of subsidiary electrodes, in accordance with a change in signal outputs when the wave front is modulated, a tilt is detected between a direction normal to the surface of an optical disk and an objective lens optical axis, and in accordance with the detected tilt, the injection currents to the semiconductor laser are determined to correct the tilt. Since the tilt is detected and corrected through electrical modulation, the system can be made compact without using new components for tilt detection, and high speed control up to a high frequency becomes possible because there is no limit of the control bandwidth to be caused by sub-resonances in a high frequency band, like a mechanical actuator.

Tilt detection method and optical disk drive

A hydraulic control circuit system comprises first and second double-acting cylinders, a hydraulic pump for supplying the double-acting cylinders with pressure oil, and directional control valves respectively associated with the cylinders for controlling the supply of pressure oil to the latter. The hydraulic control circuit system has a circuit for independently operating the individual cylinders and also a circuit for causing the rod advancing and retracting actions of the first cylinder to be followed by the rod advancing and retracting actions of the second cylinder. The system is applied to the hydraulic control circuit of, e.g., a front loader for controlling a hydraulic cylinder used for lifting and lowering the loader arm and another hydraulic cylinder used for turning the bucket pivotally connected to the free end of the arm. In that case, the system ensures that the upward and downward movements of the arm are followed by the turning of the bucket so as to prevent the load in the bucket from spilling, which would be otherwise caused by the tilting of the bucket with respect to the horizontal.

Hydraulic control circuit system

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Tsuchiura, Japan

Seiichi Kato