JPH01276478A - Floating head - Google Patents

Abstract

PURPOSE:To obtain a floating head, which minutely execute the position control of a beam spot, by providing an electro-magnetic driving mechanism which finely moves a slider to a head arm in the parallel direction of an information track on a recording carrier. CONSTITUTION:A slider 10 receives buoyancy by air flow, which is turned around an optical disk 3, alike a normal magnetic head. Then, the slider is stably floated in a position to be balanced with the load force of a supporting spring 11. An optical head 4 reads an error signal by a sample servo system, for example, so that the beam spot by a beam outgoing from the position can follow a target track. Then, on the basis of this signal, a head arm 5 is driven by a positioner, which is not shown in a figure, and controlled so that the error signal can be made small. When it is impossible to follow the oscillating component of a high frequency in a track guide channel 31 only by this control, a current to have a direction and a size, with which an error is corrected to a coil 12, flows to a permanent magnet so that the same error signal is closed to zero without limit.

Description

Detailed Description of the Invention [Industrial Field of Application] The present invention is a method for floating a record carrier such as a disk with a desired gap maintained by air force, and recording information on the record carrier optically or magnetically. and related to floating heads that perform playback.

[Conventional technology]

As a type of head used in information recording and reproducing devices,
Particularly in the field of magnetic recording, floating heads are widely used. This floating head utilizes the air flow generated on the surface of the recording carrier as it rotates to lift the slider equipped with the magnetic head off the surface of the recording carrier by a minute amount on the order of submicrons, thereby improving recording density. The aim is to

Recently, a floating head has been proposed in which a small optical head is mounted on this slider to record signals on an optical disk by optical means and/or to reproduce signals from the optical disk. An example thereof is shown in FIG.

The slider 1 is rotatably supported by a gimbal spring 2 in the rotational direction of the optical disc 3 (in the direction of arrow A) and in the width direction of the slider 1 itself, and is urged toward the side facing the optical disc 3 by the elastic force of the load arm 7. . This biasing force is balanced with the air force generated between the surface of the optical disk 3 and the lower surface of the slider 1, so that the slider 1 stably floats above the surface of the optical disk 3 with a minute gap.

On the other hand, an annular track guide groove 31 is provided on the surface of the optical disk 3, and a recording film 32 is formed on the surface. A beam emitted from the optical head 4 mounted on the slider 1 forms a beam spot a on the recording film 32 to record/reproduce signals.

Although the beam width (a) is generally small, on the order of 1 μm, the I/rack guide groove 31 swings about 100 times as much as it does due to the eccentricity of the optical disk 3, etc.

For this purpose, the head arm 5 holding the gimbal spring 2 is driven in the radial direction of the optical disk 30 (in the direction of arrow B) by a linear or swinging type actuator (not shown) to direct the beam spot a into the trunk guide groove 31. Tracking control is performed to follow the target.

However, in this type of floating head, it is strongly desired to realize high-density recording, and in the case of optical disks, the track pitch is as small as 1.6 μm, and the allowable track error is extremely small, as 0.1 μm. Due to its small size, it is difficult to control the beams by just controlling the head arm as described above.
-a cannot be controlled within the desired brightness.

Therefore, as shown in FIG. 6, the slider 1 is provided with a driving element such as a laminated piezoelectric element 6, thereby controlling the position of the optical head 4 itself more finely and directing the beam spot a toward the track guide groove 3. It has been proposed that control be performed so as to precisely follow the

[Problem to be solved by the invention]

However, in the conventional example described above, only 1c
It is necessary to assemble the laminated piezoelectric element 6 with a complicated shape onto the slider 1, which is not even large in size, and to precisely attach the optical head 4 to the tip of the element.Actual manufacturing is quite difficult. is expected. Further, if a part of the slider 1 is made of a laminated member, the flatness may be impaired and the flying characteristics of the slider 1 may be deteriorated. Furthermore, the piezoelectric element 6 has the disadvantage that a power source for driving it generally requires a high voltage, and furthermore, driving at a high frequency requires a large power source.

The present invention has been made in view of the above points,
The purpose is to provide a floating head that achieves precise beam spot position control with a simple structure.

[Means to solve the problem]

To this end, the present invention provides a floating head that is equipped with a slider that floats a recording and/or reproducing head close to the surface of a traveling record carrier, and that the slider is supported on a head arm by a support member. An electromagnetic drive mechanism is provided for the rad arm to slightly move the slider in the direction in which the information tracks on the record carrier are arranged.

[Examples] Examples of the present invention will be described below. FIG. 1 is a diagram showing a floating head in one embodiment.

The slider 10 is attached to the head arm 5 by a support spring 11. In the attached state, this support spring 11 has low rigidity in the direction (radial direction) in which the track guide grooves 31 of the optical disc 3 are arranged and/or in the diagonal direction of the track guide grooves 31, and has low rigidity in the direction facing the optical disc 3. is formed to exert the necessary load force.

FIG. 2 is a diagram showing an example of the support spring 11. Each end portion 11a, llb is defined on the slider 1 and head arm 5, respectively. The planar neck portion 11c and lid extending from this end portion 11a111b are easily bent in the Z direction, and the folded portions lie and llf extending further from there have strong rigidity in the Z direction, and the folded portion in the center has a notch portion 11g.
This makes it easier to bend in the X direction.

In this embodiment, simple coils 12 are attached to the side surfaces of the slider 10, two on one side and four on both sides. The coil 12 is defined on the side surface of the slider 10 by winding a thin wire of several tens of micrometers from one turn to several turns and fixing it with resin or the like. The lead of this coil 12 is connected to the slider 1.
0 and support spring 11, and is connected to a terminal 13, and the end thereof is connected to a drive amplifier (not shown).

Further, the head arm 5 is configured to surround three sides of the slider 10 in a U-shape, and permanent magnets 14 of the same number as the coils 12 are attached to the surface facing the coils 12 . It is desirable that the cross-sectional shape of the surface of the permanent magnet 14 facing the coil 12 be larger than that of the coil 12.

At the rear end of the slider 10, there are two optical heads 4 in this embodiment.
Individually installed. A signal line for driving the optical head 4 or reading a reproduced signal also extends along the slider 10 and the support spring 11, and is connected to a terminal 13, which is connected to an electric circuit (not shown).

A beam emitted from one end (lower surface) of the optical head 4 forms a beam spot a on the surface of the optical disk 3. Based on the strength of the reflected light from the beam spot a, an error signal necessary for tracking control, for example, an error signal based on a sample hold method, is read, and the current flowing through the coil 12 is controlled by a circuit (not shown).

FIG. 3 is a diagram for explaining the relationship and operation between the coil 12 and the permanent magnet 14, and is a diagram seen from the top of the slider 10. It is desirable that the centers of the four coils 12a to 12d substantially coincide with the centers of the four permanent magnets 14a to 14d, and the gap between the paired coils and magnets is approximately several hundred μm. The polarity of each permanent magnet 14a to 14d is
It is not limited to what is illustrated. In addition, the permanent magnets 14a to 1
It is desirable that each end of 4d is connected by a yoke or the like.

Next, the operation of the floating head configured as above will be explained. First, like a normal magnetic head, the slider 10 receives buoyancy from the air flow surrounding the optical disk 3, and stably floats at a position balanced with the load force of the support spring 11.

The optical head 4 reads an error signal by, for example, a sample servo system so that the beam spot a of the beam emitted from the optical head follows the target track, and based on this signal, the head is adjusted by a positioner (not shown). Arm 5 is driven and controlled so that the error signal becomes small.

When it is impossible to follow the high-frequency vibration component of the track guide groove 31 with this control alone, the error is corrected in the coil 12 from a circuit (not shown) so that the error signal approaches zero as much as possible. A current of certain direction and magnitude flows.

For example, when a current is passed through the coils 12a to 12d so as to generate a magnetic field having the direction indicated by the dotted line in FIG.
14b, and the coils 12c and 12d are attracted to the opposing magnets 14c and 14d, respectively. As a result, the slider 10 receives a force that moves in the direction of the arrow X, and the notch 11g of the support spring 11 deforms, causing the slider 10 to move slightly in the direction of the arrow X.

Since the slider 10 is lightweight, weighing several hundreds of milligrams, a small electromagnetic drive mechanism composed of four coils 12 and a permanent magnet 14 can cause the slider 10 to follow vibration components of sufficiently high frequencies. According to a simple calculation, slider weight: 0.1 g Number of coil turns: 1 Permanent magnet = neodymium iron with 3 fin diameters If the distance between the coil and magnet is 0.1 mm, the current flowing through the coil is 0. If it is set to about 1 A, an acceleration of about 0.4 G can be generated in the slider. In other words, the slider has an amplitude of 0.1 μm and a frequency of I
Track king control is possible by excitation at KHz.

FIG. 4 is a diagram showing another embodiment. In this embodiment, a coil 15 (15a, 15b) is wound around the slider 10 in a direction that intersects the direction in which the slider 10 is to be slightly moved, and the side surface of the coil 15, that is, the direction in which the track guide grooves 31 of the optical disc 3 are arranged. The permanent magnets 16 (16a to 16
d) is provided on the head arm 5.

In this embodiment, an electromagnetic force according to Fleming's left-hand rule is generated by the permanent magnet 16 and the current flowing through the opposing wire portions of the coil 15. Therefore, for example, if a current is passed in the direction shown by arrow I in FIG. 4 and the polarities of permanent magnets 16a to 16d are set as shown, the slider 10
receives a force that moves in the direction.

In the embodiment shown in FIG. 4, the coil 15 is not necessarily wound around the entire slider 10, but a small coil is wound around the entire slider 10 so that the portion facing the permanent magnet 16 is the wire portion facing the optical disk. It may be attached in the same manner as the embodiment shown in FIG.

Furthermore, in each of the above embodiments, the permanent magnets 14, 16 may be replaced with electromagnets. Also, the permanent magnet 14.16 and the coil 12.15 are in opposite positions, that is, the slider 1
A permanent magnet may be attached to the 0 side and a coil may be attached to the head arm 5 side.Although the above embodiment describes the case where it is applied to an optical head, it can be similarly applied to a magnetic head.

〔Effect of the invention〕

As described above, according to the present invention, since the slider is configured to be slightly displaced by the electromagnetic drive mechanism with respect to the head arm, it is possible to drive the slider in the radial direction of the record carrier with a simple configuration. In addition, the part that generates electromagnetic force can be assembled by attaching coils and magnets, so
Its manufacture is not complicated. Furthermore, since this electromagnetic drive mechanism can be driven with low current/low voltage, no special circuits such as a power supply are required.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of a floating head according to an embodiment of the present invention, and FIG.
The figure is a perspective view of a support spring that supports the slider of the floating head, Figure 3 is an explanatory diagram showing the relationship between the coil provided on the slider and the permanent magnet on the helad arm side, and Figure 4 is a slider of another embodiment. 5 is an explanatory diagram showing the relationship between the coil provided in the head arm and the permanent magnet on the head arm side. FIG. 5 is an explanatory diagram of a conventional floating head for optical disks. It is an explanatory view of a drive element. a... Beam spot, 1... Slider, 2...
Gimbal spring, 3... optical disc, 31... tiger...
Tsuk guide groove, 32... Recording film, 4... Optical head, 5
...Head arm, 6...Laminated piezoelectric element, 7...
- Load arm, 10...Slider, 11...Support spring, 12.15...Coil, 13...Terminal, 14.
16...Permanent magnet. Agent Patent Attorney Tsuneaki NagaoFigure 2Figure 3Figure 4

Claims (2)

[Claims] (1) A floating head that is equipped with a slider that floats a recording and/or reproducing head close to the surface of a traveling record carrier, and in which the slider is supported on the head arm by a support member, with respect to the head arm. A floating head comprising: an electromagnetic drive mechanism for slightly moving the slider in a direction in which information tracks are arranged on the record carrier. (2) A spring member that provides the support member with weak rigidity in the direction in which the information tracks are arranged and/or in the diagonal direction of the information tracks, and applies a necessary load force in the direction facing the record carrier. A floating head according to claim 1, characterized in that it is constructed by:.