WO2003067589A1

WO2003067589A1 - Disc drive

Info

Publication number: WO2003067589A1
Application number: PCT/IB2003/000191
Authority: WO
Inventors: John A. Harold-Barry
Original assignee: Koninklijke Philips Electronics NV
Current assignee: Koninklijke Philips NV
Priority date: 2002-02-08
Filing date: 2003-01-23
Publication date: 2003-08-14
Anticipated expiration: 2004-08-08
Also published as: AU2003201478A1; GB0202986D0

Abstract

A disc drive (1) is disclosed comprising a spindle motor (30) for driving a spindle (20) for rotating a disc (10); a pickup (12) for reading data from the disc during its rotation; and tracking means (15, 16, 17, 18) for controlling relative movement between the pickup and the spindle, wherein the spindle motor is also used to create the relative movement between the pickup and the spindle.

Description

DESCRIPTION

DISC DRIVE

This invention relates to a disc drive comprising a spindle motor for driving a spindle for rotating the disc, a pickup for reading data from the disc during its rotation and tracking means for controlling relative movement between the pickup and the spindle (hereafter "coarse tracking").

In a conventional disc drive, functions such as disc rotation, coarse tracking and loading / ejecting a disc are done independently, using separate motors. However, in order to reduce the costs of manufacturing such disc drives, it is has been recognised that some of these functions can be achieved with a reduced number of motors. For example, US patent 5467333 discloses a disc drive in which the rotation of a disc and the loading / ejecting mechanism of the disc tray are performed using a single motor. Also, US patent 6169711 discloses a disc drive in which the movement of a pickup and the loading / ejection of the disc tray are performed using a single motor.

It is an object of the invention to provide an alternative disc drive which uses a reduced number of motors.

In accordance with the present invention, a disc drive of the aforementioned kind is provided in which the spindle motor is used to create the relative movement between the pickup and the spindle.

For example, where the tracking means comprises a friction member, relative movement between the pickup and the spindle may be created by the application of the friction member, e.g. using a solenoid, against a rotating shaft, e.g. the spindle, which is connected to the spindle motor. In particular, where the relative movement between the pickup and the spindle is constrained to one axis, the tracking means . may comprises two friction members whereby movement in one or other directions of that axis is causes by applying one or other of the friction members to respective opposing sides of the rotating shaft.

As an alternative to using a friction member, the pickup may be fixed and the spindle moveable, both relative to the body of the disc drive, wherein the relative movement between the pickup and the spindle is created by changes in the rate of rotation of the disc.

The spindle motor may also be used for driving either or both of loading and ejecting the disc.

The present invention will now be described, by way of example only, with reference to the accompanying figures in which:

Figures 1a, 1b, 2a and 2b show, schematically, optical disc drives according to the present invention.

The same reference signs are generally used to refer to corresponding or similar features in different embodiments.

Figures 1a and 1b show, schematically, an optical disc drive according to the present invention in which a disc is shown in two positions 10, 10' . The disc 10 is supported by a spindle 20 mounted on a moveable carriage 21. Also, a motor (not shown) for rotating the spindle is mounted on the carriage, beneath the spindle. In the first position, the disc 10 is illuminated by a laser beam 13 of a fixed optical pickup unit 12 and the data is read from the disc. In the second position, the disc 10' is moved on the spindle towards an ejection rack 17, initially for the purpose of coarse tracking where the laser beam illuminates a different part of the disc and then to the ejection rack for the purposes of ejecting the disc from the disc drive. Movement of the spindle is constrained to a single axis using a conventional track 14 and bearing 19 arrangement.

In accordance with the present invention, movement of the pickup relative 12 to the spindle 20 is done by applying one of two friction pads 16, 16' to the rotating spindle. The friction pads are mounted on respective supports 15, 15' which are connected to the moveable carriage whereby application of one or other to the spindle causes movement in respective directions of the axis of the track 14 and bearing 19 arrangement. Application of the friction pads to the rotating spindle is controlled by a solenoid which is capable of driving a rod connected to the supports 15, 15' back and forth. Figures 2a and 2b show, schematically, an alternative optical disc drive according to the present invention. Whereas in the embodiment of figures 1a and 1 b, the motor is mounted on the carriage, in the embodiment of figures 2a and 2b, the motor 30 is fixed to the body of the disc drive (not shown) and the spindle 20 is driven by the motor via a drive belt 31. Also, movement of the carriage 21 is by a different mechanism. Instead of using friction pads, the lateral movement of the spindle along the axis of the track and bearing arrangement is caused by changes in the rotational inertia of the spindle or in other words, a change in the speed of rotation of the disc. A solenoid 18 and associated rod 19 is provided for the purposes of clamping the carriage so as to prevent its movement when, for example, the speed of rotation of the disc is increasing or decreasing.

The above embodiments are described using a fixed pick up and a moveable spindle, however, the invention is equally applicable to disc drives employing a fixed spindle and moveable pick up. Also_; the invention is equally applicable to magnetic as well as optical disc drives. It should be noted that the design and manufacturer of disc drives is very well known and therefore this disclosure is correspondingly brief.

Claims

1. A disc drive comprising:

- a spindle motor for driving a spindle for rotating a disc;

- a pickup for reading data from the disc during its rotation; and

- tracking means for controlling relative movement between the pickup and the spindle, wherein the spindle motor is also used to create the relative movement between the pickup and the spindle.

2. A disc drive according to claim 1 wherein the tracking means comprises a friction member; and wherein relative movement between the pickup and the spindle is created by the application of the friction member against a rotating shaft driven by the spindle motor.

3. A disc drive according to claim 2 wherein the tracking means comprises two friction members; wherein the relative movement between the pickup and the spindle is constrained to one axis; and wherein movement in one or other directions of that axis is causes by applying one or other of the friction members to respective opposing sides of the rotating shaft.

4. A disc drive according to claim 2 or claim 3 wherein the coarse tracking means further comprises a solenoid which is used to apply the or each friction member to the rotating shaft.

5. A disc drive according to any of claims 2 to 4 wherein the shaft and the spindle are the same.

6. A disc drive according to any of the preceding claims wherein the pickup is fixed and the spindle is moveable, both relative to the housing of the disc drive.

7. A disc drive according to claim 1 wherein the pickup is fixed and the spindle is moveable, both relative to the body of the disc drive; and wherein the relative movement between the pickup and the spindle is created by changes in the rate of rotation of the disc.

8. A disc drive according to any of the preceding claims wherein the spindle motor is also used for driving either or both of loading and ejecting the disc.