Dynamic information storage or retrieval – With servo positioning of transducer assembly over track... – Optical servo system
Reexamination Certificate
1999-07-28
2002-01-22
Tran, Thang V. (Department: 2651)
Dynamic information storage or retrieval
With servo positioning of transducer assembly over track...
Optical servo system
C369S044140, C369S044160, C359S814000, C359S812000
Reexamination Certificate
active
06341104
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an optical pickup apparatus used to record and replay an optical disk, such as high-density disk and compact disk, and also to an optical disk apparatus using the optical pickup apparatus.
2. Description of the Related Art
The optical disks, because of their advantages of easy handling and large storage capacity, have found very wide use. With a growing use occasions have come to be reported where the optical disk surface is “warped” because the disk is made of a poor-quality material or after it has been used a large number of times. To fully exploit the advantages of the optical disk, it is required that the optical pickup throw a beam perpendicular to the optical disk. The “warped” optical disk, however, cannot meet this requirement and fails to perform correct reproduction.
Conventional measures taken to cope with this problem involve changing the position of a shaft that supports and guides an optical pickup
3
to counteract the “warping,” or tilting a spindle motor unit
2
that rotates the optical disk. Because the “warping” is not uniform, however, these measures are not suited for all disks.
Another method has been proposed which tilts the optical pickup following the optical disk. This is an optical pickup of a type that arranges a coil and a magnet around an objective lens to tilt the objective, as disclosed in Japanese Patent Laid-Open No. 8-106641 for example. These optical pickups, however, are generally arranged to be supported by a plurality of elastic members and thus cannot perform a tilt control (displacement in a tangential direction described later) which extends one group of elastic members and compresses another group of elastic members.
As the computers using the optical disk as an external storage medium are becoming smaller in size and weight and there is a growing need that the computer can be carried and used whenever and wherever the user wishes to use it. Thus, there is an increasing demand also on the optical disk for reduced size, weight and thickness. With the above invention, however, because the coil and magnet are arranged around the objective lens, a block including the objective lens becomes large, blocking the way to a further reduction in the size and thickness of the optical pickup apparatus.
The present invention has been accomplished to solve the above-described problems and its object is to provide an optical pickup apparatus which enables an easy tilt control of the objective lens and which is suited for reduction in size and thickness and to provide an optical disk apparatus using such an optical pickup apparatus.
SUMMARY OF THE INVENTION
An optical pickup apparatus according to the present invention comprises: an objective lens for focusing a beam emitted from a light source onto an optical disk; a lens holding means for holding the objective lens; a plurality of elastic supporting means for elastically supporting the lens holding means so that it can be moved; and a support base means for fixedly supporting the elastic supporting means and for fixedly supporting a drive means, the drive means being adapted to movably drive the lens holding means; wherein the lens holding means has a circular space portion and an almost rectangular opening portion in which the drive means is inserted, the circular space portion being adapted to hold the objective lens and guide the beam emitted from the light source to the objective lens; wherein the elastic supporting means has a first elastic supporting means having one end thereof secured to the support base means and a second supporting means having one end thereof secured to an almost central part, with respect to a tangential direction, of the almost rectangular opening portion of the lens holding means; wherein the lens holding means is supported so that it can be pivoted in the tangential direction about the second elastic supporting means as a rotating center.
With this construction, the optical pickup apparatus can perform the tilt control in both the radial and tangential directions. Thus, it can correct radial and tangential skews caused, for example, by an optical disk warping. Further, it is possible to increase a skew margin by the tilt control, thereby assuring reliable reproduction and recording even for high-density optical disks and low-precision optical disks. Further, the space utilization of the tilt control mechanism can be improved to realize a small and thin optical pickup apparatus. The use of this optical pickup apparatus can reduce the size and thickness of the optical disk apparatus.
REFERENCES:
patent: 5446721 (1995-08-01), Sekimoto et al.
patent: 5598397 (1997-01-01), Sim
patent: 5877904 (1999-03-01), Kawano et al.
patent: 5905255 (1999-05-01), Wakabayashi et al.
patent: 5926327 (1999-07-01), Bae
patent: 5940227 (1999-08-01), Haraguchi et al.
patent: 5999501 (1999-12-01), Tomita et al.
patent: 6163416 (2000-12-01), Uekusa et al.
patent: 8106641 (1996-04-01), None
patent: 10320804 (1998-12-01), None
Aso Junya
Maki Tadashi
Yamaguchi Hideo
Matsushita Electric - Industrial Co., Ltd.
Stevens Davis Miller & Mosher LLP
Tran Thang V.
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