JPH11213419A - Optical head, and optical recording and reproducing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform the tracking operation control of an optical recording and reproducing device enabling a high density recording and reproduction by using a slider type head on which a solid-state immersion lens is mounted with high accuracy. SOLUTION: This optical head 10 is constituted by arranging a solid-state immersion lens 12 at the position near the recording surface 2a of the upper surface of an optical magnetic disk 2 in a slider 11 which is placed on the recording surface 2a of the upper surface of the optical magnetic head 2 rotated by a spindle motor 1 and positioned by being floated by an air bearing from the recording surface 2a and arranging an objective lens 13 for converging a recording and reproducing light on the lens 12 at the upper side of the lens 12. Also, the optical head 20 is held to a head arm 4 with a fine moving actuator 20, and a highly accurate tracking control is performed by the control of the fine moving actuator 20 in addition to the rotational control of the head arm 4 by a voice coil motor 3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical recording / reproducing apparatus for optically recording / reproducing information and an optical head used for the optical recording / reproducing apparatus.

[0002]

2. Description of the Related Art In recent years, in an apparatus or system for optically recording or reproducing information, particularly in a magneto-optical recording and reproducing apparatus or system, a solid immersion lens (also referred to as a solid immersion lens or a SIL) has been developed in order to improve the recording density. A recording method has been proposed in which the effective numerical aperture of the optical system is increased to 1 or more by using the same. For example, an experimental example of mounting a solid immersion lens on the flying head of a magneto-optical disk was reported by BDTerris et al.
d Physics Letter 68 (2), 141-143 (1996). FIG. 7 shows the tip of the head. This head 90 has a solid immersion lens 92 mounted on a slider 91 which floats by an air bearing.
An objective lens 93 for converging and entering a light beam to the solid immersion lens 92 is arranged on the upper part of the lens.

In such a configuration, the distance between the solid immersion lens 92 and the recording medium 95 is determined by the balance between the slider structure and its load, and the buoyancy generated by the air bearing generated by the rotation of the recording medium, and is always constant. Therefore, the focus servo mechanism is unnecessary. In the case of an optical recording / reproducing apparatus using such a head, this head is attached to the tip of a head arm, and the head is rotated by a voice coil motor provided at the root of the arm to rotate the head with respect to the rotation of the recording medium. Recording and reproduction are performed by moving (scanning) in the direction (direction intersecting the rotation direction and the rotation plane), that is, by performing a tracking operation.

[0004]

However, in such a conventional apparatus, the tracking operation is controlled only by controlling the rotation of a voice coil motor provided at the root of the head. There is a problem that operation control is difficult. In particular, recently, high-density recording / reproduction has been required, and if a slider type head equipped with a solid immersion lens as described above is used, recording at a fine pitch such that the track pitch is 1 μm or less is possible. However, there is a problem that it is difficult to perform a tracking operation with high accuracy for such a fine track pitch.

The present invention has been made in view of such circumstances.
An optical recording and reproducing apparatus capable of performing high-density recording and reproduction using a slider type head equipped with a solid immersion lens, and an object thereof is to provide an optical head and an optical recording and reproducing apparatus capable of performing tracking operation control with high accuracy. And

[0006]

In order to achieve the above object, according to the present invention, an optical recording medium (for example, an optical disk) that moves in a plane is placed on a recording surface (usually, an upper surface or a surface of the disk). A solid immersion lens is disposed at a position close to the recording surface of the optical recording medium on a slider positioned above the recording surface by an air bearing, and the recording / reproducing light is focused on the solid immersion lens above the solid immersion lens. An optical head is configured by arranging an objective lens, and further,
The slider is configured to be held on the head arm via a fine actuator.

When optical recording and reproduction are performed using the optical head having such a configuration, an optical recording medium (magneto-optical disk) is used.
The slider held by the head arm is placed on the recording surface of the optical recording medium in a state where is moved in a plane (for example, rotated). At this time, the slider floats while maintaining a certain distance from the recording surface of the optical recording medium due to an air bearing effect generated by the relative movement between the slider and the optical recording medium. Then, the solid immersion lens is irradiated with recording / reproducing light from outside through an objective lens. At this time, the recording / reproducing light is condensed on the objective lens and guided to the solid immersion lens to form a converged spot on the optical recording medium, and information is recorded / reproduced using the converged spot. The size of this condensed spot is 1 / n when the refractive index of the solid immersion lens is n, compared to the case where no solid immersion lens is provided. High-density recording and reproduction at a fine track pitch becomes possible.
Since the slider always floats at a fixed distance by the air bearing, a focused spot can always be formed on the recording surface of the optical recording medium without using a focusing mechanism.

[0008] By the way, when performing high-density operation at such an extremely narrow track pitch, it is necessary to perform very high-precision tracking movement control corresponding to the track pitch. When the optical head of the present invention is used, the head arm holding the optical head is rotated by a voice coil motor or the like to perform basic tracking movement control, and further, fine tracking movement control is performed by a fine movement actuator. . For this reason, fine tracking movement control, which is difficult in rotational drive control of a voice coil motor or the like, can be supplemented by the fine movement actuator, and high-density recording and reproduction at an extremely narrow track pitch can be performed accurately.

In the slider constituting the optical head according to the present invention, a portion forming an optical path for recording / reproducing light which is condensed on the solid immersion lens through the objective lens and reaches the optical recording medium is composed of recording / reproducing light. Therefore, this part of the slider may be formed as a gap or formed of a transparent material.

In the optical head according to the present invention, it is preferable that an optical mirror for guiding recording / reproducing light emitted from the outside to the objective lens is provided on the slider. At this time, the optical mirror can be configured by adding a reflective film to the optical prism.

Further, in the optical head according to the present invention, a coil-shaped conductive wiring is provided at a position facing the optical recording medium in the slider, and the magnetic field of the optical recording medium can be modulated by the conductive wiring. It is preferable that the recording be overwritten.

The fine movement actuator constituting the optical head according to the present invention can be constituted by an actuator using any one of electrostatic drive, piezoelectric drive and electromagnetic drive.

An optical recording / reproducing apparatus according to the present invention is constituted by using the optical head according to the present invention as described above, and has a medium drive mechanism (for example, a magneto-optical device according to the embodiment) for holding an optical recording medium and performing plane motion. A spindle motor 1 for rotating the disk 2, a head arm for holding the optical head, and an arm drive mechanism (for example, an arm drive mechanism for driving the head arm to move the optical head in a direction intersecting the direction of the plane movement of the optical recording medium). , The voice coil motor 3) according to the embodiment. Note that a plurality of optical recording media may be held by a medium drive mechanism. In this case, a plurality of optical heads are provided corresponding to each optical recording medium to constitute an optical recording / reproducing apparatus.

In this optical recording / reproducing apparatus, a head arm holding an optical head is driven to rotate by an arm driving mechanism to perform basic tracking movement control, and further, fine tracking movement control is performed by a fine movement actuator. For this reason, fine tracking movement control, which is difficult in the rotational drive control of the voice coil motor, can be supplemented by the fine movement actuator, and high-density recording and reproduction at an extremely narrow track pitch can be accurately performed.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the drawings. FIGS. 1 and 2 show an optical recording / reproducing apparatus as a first embodiment of the present invention. The apparatus is located close to an upper surface recording surface 2a of a magneto-optical disk 2 driven to rotate by a spindle motor 1. An optical head 10, a head arm 4 for holding the optical head 10, a voice coil motor 3 for rotating the head arm 4, and a light irradiation device 5 for irradiating recording / reproducing laser light. It is composed.

The optical head 10 has a slider 11, which is located above the upper recording surface 2a of the rotating magneto-optical disk 2 and floats a certain minute distance from the upper recording surface 2a by an air bearing effect. (Ie, constitute a flying head). The head arm 4 is connected to the voice coil motor 3 and driven to rotate, a rotating shaft 4a, an arm 4b extending horizontally from the upper end of the rotating shaft 4a, and an optical head 10 at the tip of the arm 4b. And a suspension section 4c that supports the movable section so as to allow movement. When the rotary shaft 4a is rotationally driven by the voice coil motor 3, the arm 4b is swung horizontally and the optical head 10 is moved substantially perpendicularly to the rotation direction of the magneto-optical disk 2 (the direction of arrow A in FIG. 2). And the optical head 10 is scanned on the upper recording surface 2a of the magneto-optical disk 2. That is, tracking control is performed by the voice coil motor 3.

In the optical head 10, the slider 11
A circular tapered space 11a extending upward is formed at
A solid immersion lens 12 is provided below the space 11a, and an objective lens 13 is provided above the space 11a. Slider 1
1 is provided with a micro prism 15 via a spacer 14.
And a high reflection film 16 is provided on the reflection surface 15a. The microprism 15 is connected to the suspension 4c of the head arm 4 via the fine movement actuator 20. The space 11a may be filled with a transparent or light-transmitting material.

FIG. 3 is an enlarged view of the fine movement actuator 20, which is a parallel plate type fine movement actuator made of silicon. Specifically, it is configured to have a fixed block 23 and a movable block 24 provided on the first substrate 21 joined to the suspension portion 4c, and the blocks 23 and 24 extend in parallel with each other and have a large number of opposing parallel members. It has a flat plate. By applying a voltage between these parallel plates to apply an electrostatic force, the movable block 24 is finely moved relative to the fixed block 23 in a direction perpendicular to the parallel plates (the direction of arrow B), thereby providing fine and highly accurate movement control. Is available.

That is, this fine movement actuator is an electrostatic drive type actuator. The movable block 24 is further joined to the microprism 13. Therefore, when a voltage is applied between the parallel plates and the movable block 24 is slightly moved, the optical head 10 is moved in the direction of arrow B with respect to the suspension unit 4 c. Can be fine-tuned. In addition,
The direction of the arrow B is the same as the moving direction A for scanning the optical head 10 by the voice coil motor 3.

A reflection mirror 6 is disposed on the rotating shaft 4a of the head arm 4 so as to face the light irradiating device 5 at an angle.
The recording / reproducing laser light emitted from the light irradiation device 5 is reflected by the reflection mirror 6 and guided to the microprism 15 as shown by chain lines R1 and R2 in FIGS. The recording / reproducing laser beam guided to the microprism 15 in this manner is applied to the reflection surface 1 of the microprism 15.
After being reflected by the high reflection film 16 of FIG.
3, the light is focused on the solid immersion lens 12, and the solid immersion lens 12 forms an extremely small focused spot on the upper recording surface 2a of the magneto-optical disk 2.

The operation of the optical recording / reproducing apparatus having the above configuration will be described. First, the magneto-optical disk 2 is rotated at a predetermined speed by the spindle motor 1. At this time, the optical head 10 supported by the suspension portion 4c of the head arm 4 and arranged on the upper recording surface 2a of the disk 2
The slider 11 floats by a minute distance from the upper recording surface 2a due to the air bearing effect. In this state, a recording / reproducing laser beam is irradiated from the light irradiation device 5,
As shown by chain lines R1 and R2, the light is reflected by the reflection mirror 6 and enters the microprism 15. Then, the light is reflected by the reflecting surface 15 a of the microprism 15, condensed by the objective lens 13, is incident on the solid immersion lens 12 and is converged, so that a condensed spot is formed on the upper recording surface 2 a of the magneto-optical disk 2.

Here, the magneto-optical disk 2 is driven at a constant speed, and the flying height of the slider 1 is always constant.
The distance from the solid immersion lens 12 to the converging spot is set to be the same. For this reason, it is possible to always form a converging spot on the upper recording surface 2a of the magneto-optical disk 2, and it is not necessary to provide a focusing mechanism as in the related art.

When information is recorded by the thus formed condensed spot light, first, the condensed spot is heated to a temperature higher than the Curie temperature by a laser beam applied thereto, and the condensed spot is heated by a magnetic field applied from the outside. The information recording is performed by changing the magnetism of the portion, but since this is already known, an apparatus for applying a magnetic field is not shown, and the operation description thereof is omitted. For reproducing (reading) information, a device for detecting the magneto-optical Kerr effect is used, but illustration and description thereof are also omitted.

Such recording and reproduction is performed on the magneto-optical disk 2
The optical head 10 is moved (scanned) in the radial direction of the magneto-optical disk 2 in accordance with the rotation of the optical head 10. The scanning or tracking of the optical head 10 is performed by a voice coil disposed at the root of the head arm 4. This is performed by rotating the head arm 4 by the motor 3. However, here, the voice coil motor 3 is used as a coarse movement servo, and controls a relatively low-speed component of the head arm 4. That is, since the precision of tracking control by the voice coil motor 3 is limited and fine tracking control is difficult, this is used for coarse movement servo control, and control of minute and high-speed components that cannot be overtaken by coarse movement servo control is fine movement. Actuator 20
This is done by applying fine movement servo. As a result, optical recording and reproduction at ultra-high density becomes possible.

That is, according to the present apparatus, a very small condensed spot is formed by using the solid immersion lens 12, and very fine tracking control is performed by the fine movement actuator 20. Playback recording is possible.

Next, with respect to different embodiments of the present invention,
This will be described with reference to FIG. The optical recording / reproducing apparatus shown in FIG. 1 includes a spindle motor 1 for rotating a magneto-optical disk 2, a voice coil motor 3 for rotating a head arm 4 ', and a light irradiation apparatus 5 for irradiating a recording / reproducing laser beam (see FIG. Is not shown) and the reflection mirror 6 is shown in FIG.
2 are the same as those of the apparatus shown in FIG.

In this device, the optical head 50 is supported by the head arm 4 'via the suspension device 8 and the fine actuator 60. Head arm 4 '
Is a rotary shaft 4 that is rotated and driven by the voice coil motor 3
a 'and an arm portion 4b' extending horizontally from the upper end of the rotating shaft 4a '. A fine actuator 60 is attached to the tip of the arm portion 4b'. Thus, the optical head 50 is supported.

The optical head 50 is disposed below the slider 51 which floats by the air bearing when the magneto-optical disk 2 is rotated, and in the space 11 which is formed in a circular taper shape and extends upward in the slider 51. A solid immersion lens 52, an objective lens 53 disposed above the gap 11 so as to face the solid immersion lens 12, and a micromirror (optical mirror) 5 having a mirror surface 56 made of a highly reflective film layer
The micro mirror 55 is supported by the suspension device 8. The slider 51
May be filled with a transparent or light-transmissive material to form a slider. The micro mirror 55 may be made of the same material as the slider.

Further, in this optical head 50,
A microcoil 57 having a coil-shaped conductive wiring 58 as shown in FIG. By energizing the wiring 58, the micro coil 5 on the upper recording surface 2 a of the magneto-optical disk 2 is
7 modulates the magnetic field of the opposing portion to enable overwriting of recording.

The fine movement actuator 60 is composed of a piezoelectric actuator (piezoelectrically driven actuator) in which a laminated piezoelectric element 63 is connected between a fixed block 61 and a movable block 62 as shown in the figure. The fixed block 61 is connected to the arm portion 4b 'of the head arm 4', and the movable block 62 is connected to the suspension device 8. By controlling the energization of the piezoelectric element 63, the movable block 62 is moved with respect to the fixed block 61 in the direction of arrow B. Can be controlled with high precision.

The operation of the optical recording / reproducing apparatus having the above configuration will be described. Magneto-optical disk 2 with spindle motor 1
When the suspension device 8 is rotated at a predetermined speed by the
The optical head 50 supported by the head arm 4 'via the upper surface and disposed on the upper recording surface 2a of the disk 2 has a slider 51 in which the upper recording surface 2a floats by a minute distance due to the air bearing effect. In this state, a recording / reproducing laser beam is irradiated from the light irradiation device 5, is reflected by the reflection mirror 6, and enters the micro mirror 55. Then, the light is reflected by the mirror surface 56 of the micromirror 55, is condensed by the objective lens 53, is incident on the solid immersion lens 52, is converged, and a condensed spot is formed on the upper recording surface 2 a of the magneto-optical disk 2.

As described above, the magneto-optical disk 2 is driven at a constant speed, the flying height of the slider 1 is always constant, and the distance from the solid immersion lens 12 to the condensing spot is equal to this flying height. The focusing spot is always formed on the upper recording surface 2a of the magneto-optical disk 2 without using a focusing mechanism. Then, recording and reproduction of information are performed by the condensed spot light thus formed.

At the time of such recording and reproduction, the control for scanning (tracking) the optical head 50 in the radial direction of the magneto-optical disk 2 in accordance with the rotation of the magneto-optical disk 2 is as follows.
This is performed by rotating the head arm 4 ′ by the voice coil motor 3. However, also in this case, the voice coil motor 3 is used as a coarse movement servo, and controls the relatively low-speed component of the head arm 4.
This is done by applying fine movement servo. As a result, optical recording and reproduction at ultra-high density becomes possible.

In this optical recording / reproducing apparatus, a microcoil 57 is provided on the bottom surface of the slider 51, and when the conductive wiring 58 is energized, the microcoil 5 on the upper recording surface 2a of the magneto-optical disk 2 is turned on.
It is possible to overwrite the recording by performing the magnetic field modulation of the portion where 7 faces.

In the above embodiment, the rotation of the head arm is controlled by the voice coil motor, which is a rotary actuator. However, the head arm may be rotated by a linear actuator. . Further, the fine movement actuator may be configured using not only an electrostatic or piezoelectric actuator but also an actuator using an electromagnetic force. In addition, the optical recording medium is not limited to the above-described magneto-optical disk, but includes any medium that performs recording and reproduction using light, such as an optical disk.

Further, with the optical head structure according to the present invention as shown in the above embodiments, the entire optical head can be reduced in size, thickness, and weight. For this reason,
The optical heads may be stacked and arranged in the same housing to form a multiplatter-type compact optical recording / reproducing apparatus having a plurality of magneto-optical disks and optical heads.

[0037]

As described above, according to the present invention,
High-accuracy tracking control can be performed using a small and lightweight optical head having a solid immersion lens mounted on a slider, and ultra-high-density recording and reproduction can be performed. Further, since the size and weight can be reduced in this way, the inertial mass of the optical head device can be reduced, high-speed tracking can be performed, and the data access time can be reduced. Further, since the optical head is reduced in size and weight, the entire configuration of the optical recording and reproducing apparatus can be reduced in size and weight, and a multi-platter type optical recording and reproducing apparatus having a plurality of recording media and a plurality of optical heads is constituted. Thus, a compact and large-capacity optical recording apparatus can be obtained.

[Brief description of the drawings]

FIG. 1 is a schematic front view showing a configuration of an optical recording / reproducing apparatus according to a first embodiment of the present invention.

FIG. 2 is a schematic plan view showing the configuration of the optical recording / reproducing apparatus.

FIG. 3 is a perspective view showing a fine movement actuator constituting the optical recording / reproducing apparatus.

FIG. 4 is a schematic front view showing a configuration of an optical recording / reproducing apparatus according to a second embodiment of the present invention.

FIG. 5 is a bottom view showing a configuration of a microcoil provided on a bottom surface of a slider constituting an optical head of the optical recording / reproducing apparatus.

FIG. 6 is a perspective view showing a fine movement actuator constituting the optical recording / reproducing apparatus.

FIG. 7 is a schematic front view showing a configuration of a conventional optical head.

[Explanation of symbols]

 1 Spindle motor 2 Magneto-optical disk 4, 4 'Head arm 10, 50 Optical head 20, 60 Fine movement actuator 12, 52 Solid immersion lens 13, 53 Objective lens 15 Micro prism 55 Micro mirror 57 Micro coil

Claims (8)

[Claims] 1. A slider which is placed on a recording surface of an optical recording medium which moves in a plane and floats from the recording surface by an air bearing, and is disposed at a position in the slider which is close to the recording surface of the optical recording medium. A solid immersion lens, an objective lens disposed on the slider above the solid immersion lens, and condensing recording / reproducing light on the solid immersion lens, a head arm for holding the slider and moving in a plane, and An optical head, comprising: a fine movement actuator disposed between the head arm and the slider to slightly move the slider in a plane moving direction with respect to the head arm. 2. A part of the slider, which forms an optical path for the recording / reproducing light that passes through the objective lens and is condensed on the solid immersion lens and reaches the optical recording medium, with respect to the recording / reproducing light. The optical head according to claim 1, wherein the optical head has a light transmitting property. 3. The slider according to claim 1, wherein an optical mirror for guiding the recording / reproducing light emitted from the outside to the objective lens is provided on the slider.
An optical head according to item 1. 4. The optical head according to claim 3, wherein the optical mirror is formed by applying a reflection film to an optical prism. 5. A coil-shaped conductive wiring is provided at a position of the slider facing the optical recording medium, and the conductive wiring can modulate the magnetic field of the optical recording medium. The optical head according to claim 1, wherein: 6. The optical head according to claim 1, wherein the fine movement actuator is an actuator using any of electrostatic drive, piezoelectric drive, and electromagnetic drive. 7. A medium drive mechanism that holds an optical recording medium and moves it in a plane, the optical head according to claim 1, a head arm that holds the optical head, and the optical head An optical recording / reproducing apparatus, comprising: an arm driving mechanism for driving the head arm so as to move the optical recording medium in a direction intersecting a plane movement direction of the optical recording medium. 8. The optical recording / reproducing apparatus according to claim 7, wherein a plurality of optical recording media are held by the medium driving mechanism, and a plurality of the optical heads are provided corresponding to each of the optical recording media. .