JPH02236842A - Bias magnet moving mechanism serving also as optical head access - Google Patents

Abstract

PURPOSE:To attach a bias magnet by means of support at two points in a shaft circuit mechanism and to decrease energy consumption by simultaneously and rotatively moving an optical head and the bias magnet with the use of a motor and a gear. CONSTITUTION:A head 12 equipped with a laser diode, a detector, and an objective lens is turned through a worm gear 22, a relay gear 24 and a flat type gear 26 around a shaft 18 by a motor 20. Thus a moving mechanism 10 serving also as an access of the optical head 12 is supported by the two points of the shaft 18 and the flat type gear 26. A bias magnet 30 is attached to the head 12 by an L-shaped fixture 28 attached at a position shifted from the shaft 18. Thus the small bias magnet can be attached, the energy consumption is decreased, and anti-vibration property is increased.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention provides an optical head access/bias magnet moving mechanism (hereinafter simply referred to as "access") that accesses the optical head used in the magneto-optical disk drive 24 and moves the bias magnet. (also referred to as a moving mechanism). (Prior Art) A magneto-optical disk device has an optical head access RWi for accessing tracks on a magneto-optical disk, and a bias magnet used together with the optical head to erase and write on the magneto-optical disk. are doing. Access mechanisms for optical heads used in magneto-optical disk drives can be broadly divided into linear movement mechanisms that move the optical head parallel to the tracking direction (radial direction) of the disk, and rotational movement mechanisms that use the tracking direction (radial direction) as a fold line. It can be divided. The optical head is moved using two methods: method 1, which combines a motor and gears, and method 1, which uses a linear motor to directly move the optical head.

In addition, in the case of a linear motor, the efficiency is low, so without exception, a large fixed bias magnet is used that covers the entire tracking area, and even in the case of a motor, a fixed bias magnet, which is almost the same in design, is used. ing. (Problem to be Solved by the Invention) However, in the linear movement mechanism of the optical head, in order to guarantee the parallelism and horizontality of the slide part on which the head moves, as well as smooth movement, parts accuracy and Managing assembly accuracy takes time, making it difficult to reduce manufacturing costs. Since the rotary movement mechanism supports the moving machine ellipse at one point (the center of rotation), it is easier to guarantee accuracy in the manufacturing process compared to the linear movement mechanism, but it does not have the problem of the load being applied to that one point. I'm leaving it behind. In other words, in the rotary movement mechanism, there were problems with the strength and durability of the support mechanism, as well as its earthquake resistance, due to the elliptical one-point support. For this reason, in the past, it was completely unthinkable to attach a bias magnet to a rotational movement mechanism. On the other hand, the inherent problem with large fixed bias magnets is that the power consumption to generate the bias magnetic field increases, and the problem of power consumption, including heat generation, has not been solved. Therefore, an object of the present invention is to provide an optical head access/bias magnet in which a small bias magnet that generates less heat and consumes less power is attached so as to be movable so as to cover the entire tracking area of a magneto-optical disk, instead of a fixed bias magnet. The purpose is to provide a transportation mechanism. (Means for Solving the Problems) In order to achieve the above-mentioned object, the present invention provides an optical head access/bias magnet moving mechanism used in a magneto-optical disk device, which is mounted so as to rotate about a rotation axis. a bias magnet attached to the optical head and placed on the opposite side of the optical head across the magneto-optical disk; The present invention employs an optical head access/bias magnet moving mechanism characterized by having a drive mechanism that applies a driving force to other parts of the optical head. In particular, the present invention makes it possible to attach a bias magnet by using a two-point support mechanism for the access and movement mechanism instead of the conventional one-point support mechanism. (Example) Next, a preferred example of the present invention will be described with reference to the drawings. FIG. 1 is a plan view showing the optical head access/bias magnet moving mechanism of the present invention, FIG. 2 is a plan view showing the optical head of the optical head access/bias magnet moving mechanism, and FIG. 3 is a plan view showing the optical head access/bias magnet moving mechanism of the present invention. FIG. 3 is a front view of the access/bias magnet movement mechanism.

1 to 3, the access and movement mechanism 10
has an optical head 12. The optical head 12 is
As shown in FIG. 2, it has a laser diode 14, a detector 16, and an objective lens 32, and is configured to be rotated about a rotation axis 18 (FIG. 2). Also,
The optical head 12, as shown in FIG. 1 and the third section,
The motor 20 causes a worm gear 22, a relay gear 24,
It is rotated about the aforementioned rotating shaft 18 via a flat gear 26. Thus, the access and movement mechanism 1 of the present invention
0. Specifically, the optical head 12 is supported at two points: the rotational axis 18 and the flat gear 26. The bias magnet 30 is attached to the optical head 12 by an L-shaped fixture 28 attached to the optical head 12 at a position offset from the rotation axis 18. As mentioned above, the use of a two-point support mechanism improves vibration resistance, and along with the miniaturization of the bias magnet, it has become possible to attach a bias magnet. As shown in FIG.
is located between the objective lens 32 of the optical head 12 and the disk cassette 40 supported by the spindle motor, and as shown in FIG. It is possible to move between the innermost circumferential position and the outermost circumferential position within the range of the window frame 44. 30' shows the bias magnet in the outermost position. In this way, since the small bias magnet 30 can move in synchronization with the optical head 12, it can cover the range covered by the conventional large fixed bias magnet.

(Effects of the Invention) As explained in detail above, the present invention allows the optical head and the bias magnet to be rotated at the same time by a motor and gears, thereby (1) enabling two-point support by the shaft rotation mechanism, making it earthquake resistant. Improved mobility. (2) Since the holding portion of the bias magnet is placed at a position different from the rotation axis of the optical head, the magnet can be moved within the disk cassette window. (3) The position of the drive motor can now be changed freely by changing the shape and positional relationship of the gears. (4) By downsizing the bias magnet and using a motor, it has become possible to reduce power consumption and heat generation. (5) It has become possible to overwrite magneto-optical disks by magnetic modulation using a simple rotational movement mechanism without using the conventional complicated mechanism.

[Brief explanation of drawings]

FIG. 1 is a plan view showing the optical head access/bias magnet moving mechanism of the present invention. Figure 2 is a plan view showing the optical head of the optical head access/bias magnet moving mechanism. Figure 3 is a front view of the optical head access/bias magnet moving mechanism. DESCRIPTION OF SYMBOLS 10... Optical head access and bias magnet moving mechanism, 12... Optical head, l8... Rotating shaft, 20... Motor, 22... Worm gear, 24... Relay gear, 26... Flat gear, 30...Bias magnet, 40...Disk cassette, 44...Disk cassette window frame. Figure 1 Figure 3

Claims (3)

[Claims] (1) In an optical head access/bias magnet moving mechanism used in a magneto-optical disk device, an optical head is mounted to rotate around a rotation axis, and a magneto-optical disk is sandwiched between the optical head and a magneto-optical disk on the opposite side of the optical head. A bias magnet arranged and attached to the optical head, and a drive mechanism that applies a driving force to another part of the optical head different from the rotation axis so as to rotate the optical head about the rotation axis. Features an optical head access and bias magnet movement mechanism. (2) In the optical head access/bias magnet moving mechanism according to claim 1, the drive mechanism includes a motor, a worm gear attached to the rotating shaft of the motor, a relay gear that engages with the worm gear, and a relay gear that engages with the relay gear. and an arc-shaped flat gear attached to the optical head. (3) In the optical head access/bias magnet moving mechanism according to claim 1, the bias magnet is attached to the optical head at a position offset from the rotation axis of the optical head. Moving mechanism.