JP3812932B2 - Slider transfer device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a slider transfer device, and more particularly to a non-contact transfer device for a flying slider equipped with a solid immersion lens.
[0002]
[Prior art]
In order to improve the recording density of an optical disk, it is necessary to use a short wavelength laser beam and an objective lens having a large numerical aperture. However, it is not easy to develop a semiconductor laser that generates laser light with a short wavelength. In order to increase the numerical aperture of the objective lens, the diameter of the objective lens may be increased. However, the optical head itself is undesirably enlarged.
[0003]
Therefore, it has been proposed to record information on an optical disk using a solid immersion lens. In this case, the laser beam condensed by the objective lens is further converged, and a minute spot can be formed by using this solid immersion lens.
[0004]
FIG. 5 shows a schematic structure of a conventional slider transfer device. In FIG. 5, the flying slider 52 mounts and holds the above-described solid immersion lens, and the distance between the optical disk 51 and the solid immersion lens is 50 to 100 nm during recording by the flying slider 52.
[0005]
[Problems to be solved by the invention]
By the way, when the flying slider 52 mounted with the above-described solid immersion lens is loaded onto the rotating optical disk 51, the support portion 54 of the suspension 53 to which the flying slider 52 is attached is moved up and down as shown in FIG. As a result, the distance (height) was gradually narrowed from a distant position to approach the disc surface. FIG. 6 is a diagram showing the relationship between the slider and the surface runout of the conventional slider transfer device on the time axis.
[0006]
However, the rotating optical disk vibrates up and down at high speed due to surface wobbling, and it is assumed that the above-mentioned slider collides before it normally loads and floats. In particular, a solid immersion lens has a high possibility of contact or collision because the flying height must be reduced in order to record at high density.
[0007]
The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a slider transfer device that avoids contact or collision between a slider, particularly an immersion lens, and an optical disk.
[0008]
[Means for Solving the Problems]
In order to solve the above-described problems, the present invention provides a surface runout that detects the amount of runout of the disk in a slider transport device that transports a slider equipped with information reading or writing means to a predetermined position in a direction close to the disk. An amount detection means; and a transfer control means for controlling the transfer amount of the slider so that the distance between the disk and the slider becomes a target interval based on the detected amount of surface deflection , and the transfer control means Comprises a Z stage control means for controlling the transfer amount of the Z stage that moves in the direction approaching the disk while supporting the slider, and a position correction coil for correcting the position of the slider moved by the Z stage, Correction coil control means for controlling based on the surface tilt amount .
[0009]
With the above configuration, the amount of surface runout of the disk is detected, and the amount of slider movement is controlled based on the amount of surface runout so that the distance between the disk and the slider becomes the target distance. Thus, the slider approaches the disk while moving up and down, and this reduces the possibility that the slider will contact or collide with the disk, improving the reliability of the information recording / reproducing apparatus.
[0013]
Further, according to the present invention, in addition to the above-described features, the position correction coil is provided in the vicinity of the slider, and by supplying a direct current, a magnetic field is generated in the axial direction of the coil that is the downward direction of the slider. The Z stage control means sets the position separated from the disk by an arbitrary distance as an initial position, and lowers the slider at a predetermined speed from the initial position toward the disk as the disk rotates, The correction coil control means sets an initial state where the slider is balanced with an elastic force of a suspension supporting the slider by a magnetic field generated by passing a current through the position correction coil. The AC current corresponding to the surface runout is interlocked so that the slider moves while maintaining a certain distance from the disc runout. Superimposed on a DC current flowing in the position correction coil, wherein the Z stage is characterized by stopping the superposition of the alternating current to the position correction coil when stopping at a final position.
[0015]
In addition to the above-described features, the present invention is characterized in that the slider is a flying slider that holds a solid immersion lens that converges light collected by the objective lens.
[0016]
As a result, the amount of surface deflection of the disk is detected, and the amount of movement of the slider is controlled based on the amount of surface deflection so that the distance between the disk and the slider becomes the target distance. As the slider moves up and down, it approaches the disk. Therefore, the possibility that the slider contacts or collides with the disk is reduced, and the reliability as the information recording / reproducing apparatus is improved. This is particularly effective when used in a flying slider equipped with a solid immersion lens that requires a small flying height for high-density recording.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 is a view showing an embodiment of a slider transfer device of the present invention. In the figure, reference numeral 11 denotes an optical disk, and the flying slider 12 is positioned with a predetermined gap from the optical disk 11. The flying slider 12 is supported by a suspension 13 having an appropriate elasticity, and the suspension 13 is held by an actuator that can move up and down in the Z direction and a support portion. Hereinafter, the actuator and the support portion will be referred to as the moving Z stage 14 for convenience. Reference numeral 15 denotes a loading control circuit. The loading control circuit 15 is supplied with a Z stage position signal from the moving Z stage 14 and a surface shake signal from the laser interference displacement meter 17, and based on these signals, a Z stage control signal and a correction coil are described later. Control signals are generated and supplied to the moving Z stage 14 and the position correction coil 16, respectively.
[0018]
Reference numeral 16 denotes a position correction coil added according to the present invention. The position correction coil 16 may be supported by the moving Z stage 14 described above and move up and down together with the moving Z stage 14 or may be fixed to a part of a frame (not shown). When a predetermined current is supplied to the position correction coil 16 as a correction coil control signal by the loading control circuit 15, a magnetic field in the Z direction (coil axial direction) is generated. A part of the flying slider 12 or the suspension 13 described above is formed of a magnetic material, and receives the Z-direction force generated by the magnetic field generated by the position correction coil 16, and moves while maintaining a certain distance from the surface deflection of the optical disk 11. Thus, the flying slider 12 is controlled.
[0019]
The laser interference type displacement meter 17 is arranged on the upper surface of the optical disk 11 with an appropriate interval, measures the amount of surface vibration of the optical disk 11 according to the principle of laser interference, and supplies it to the loading control circuit 15 as a surface vibration signal. If the disk is transparent, it can be arranged on the lower surface.
[0020]
FIG. 3 is a diagram cited for explaining the operation of the embodiment of the present invention shown in FIG. 1 and mainly shows the flow of control by the loading control circuit 15.
[0021]
Hereinafter, the operation of the embodiment of the present invention shown in FIG. 1 will be described in detail with reference to FIG. First, in the initial state (a), the moving Z stage 14 is stationary at an initial position away from the optical disk 11. Further, a direct current is supplied to the position correction coil 16, and a direct magnetic field generated thereby causes an attractive force to act on the magnetic piece 21 provided on the flying slider 12, so that the position correction coil 16 balances with the elasticity of the suspension 13. It has become.
[0022]
Next, in (b), the surface shake is measured by the laser interference displacement meter 17 as the optical disk 11 rotates. The loading control circuit 15 supplies a current to the position correction coil 16 so that the flying slider 12 moves at a constant interval. That is, the loading control circuit 15 supplies the Z stage control signal to lower the moving Z stage 14 at a constant speed and starts the loading operation. As a result, the movable Z stage 14 descends from the initial position toward the optical disc 11 at a predetermined speed. The loading control circuit 15 further weights the alternating current corresponding to the surface shake to the direct current so that the flying slider 12 moves with a certain distance from the surface shake of the optical disc 11, and sends a correction coil control signal to the position correction coil 16. Supply as.
[0023]
In (c), as the position of the moving Z stage 14 is lowered and the gap between the optical disk 11 and the flying slider 12 is narrowed, the flying slider 12 receives a flying force due to the rotation of the optical disk 11. When the moving Z stage 14 is lowered, a constant gap is maintained that balances the levitation force and the elasticity of the suspension 13, and the loading is completed. In this state, since the position correction by the position correction coil 16 is not necessary, the supply of alternating current is stopped. That is, the moving Z stage 14 continues to descend and then stops at the final position where a predetermined gap is obtained. After the moving stage 14 stops at the final position, the supply of the correction coil control signal to the position correction coil 16 also stops. .
[0024]
By controlling the position correction coil 16 in this way, loading control can be performed while the relative position between the optical disk 11 and the flying slider 12 is small, so that contact or collision can be avoided.
[0025]
FIG. 2 is a view showing another embodiment of the slider transfer device according to the present invention. In the figure, the components denoted by the same reference numerals as those shown in FIG. 1 are the same as those shown in FIG. Here, the difference from the embodiment shown in FIG. 1 is that a gap between the optical disc 11 and the flying slider 12 is detected in addition to the surface deflection. That is, the laser interference type displacement meter 17 measures the gap from the difference between the surface deflection and the displacement of the flying slider 12 using the measurement light of both the surface deflection and the flying slider 12. Others are the same as the embodiment shown in FIG.
[0026]
FIG. 4 shows the loading operation of the embodiment of the present invention shown in FIG.
Hereinafter, the operation of the embodiment of the present invention shown in FIG. 2 will be described in detail with reference to FIG. First, in the initial state (a), the moving Z stage 14 is stationary at an initial position away from the optical disk 11. Further, a DC current is supplied to the position correction coil 16, and a DC magnetic field generated thereby causes an attractive force to act on the magnetic piece 21 provided on the flying slider 12, so that the position correction coil 16 balances with the elastic force of the suspension 13. It has become.
[0027]
Next, in (b), as the optical disk 11 rotates, the gap between the optical disk surface and the flying slider 12 is measured, and feedback control is performed so that the gap becomes the set target value by the magnetic field of the position correction coil 16. . At the same time, the moving Z stage 14 is lowered at a constant speed, and the loading operation is started. In other words, the loading control circuit 15 supplies a Z stage control signal to the moving Z stage 14, whereby the moving Z stage 14 descends from the initial position toward the optical disk 11 at a predetermined speed. Further, the position correction coil 16 is changed to an appropriate target value set in advance at each Z position in conjunction with the lowering of the moving Z stage 14.
[0028]
In (c), as the position of the moving Z stage 14 is lowered and the gap between the optical disk 11 and the flying slider 12 is narrowed, the flying slider 12 receives a flying force due to the rotation of the optical disk 11. When the movable Z stage 14 is lowered, a constant gap is maintained that balances the floating force and the elastic force of the suspension, and the loading is completed here. That is, the moving Z stage 14 continues to descend and stops at the final position where a predetermined gap is obtained. After the moving stage 14 stops at the final position, the supply of the correction coil control signal to the position correction coil 16 is also stopped.
[0029]
By controlling the position correction coil 16 in this way, loading control can be performed while the relative position between the optical disk 11 and the flying slider 12 is small, so that contact or collision can be avoided.
[0030]
As described above, according to the present invention, as shown in the embodiment in FIG. 1, the floating slider 12 or the suspension 13 that is a supporting portion thereof is provided with the movable Z stage 15 that can move up and down at high speed, and the laser interference displacement meter. 17, the surface vibration of the optical disk 11 is measured, and the loading control circuit 15 loads the flying slider 12 close to the optical disk 11 while applying a signal corresponding to the time waveform to the flying slider 12, or FIG. As shown in the embodiment, after the gap between the optical disk 11 and the flying slider 12 is measured by the laser interference displacement meter 17 and the height of the flying slider 12 is controlled by the loading control circuit 15 so that the space is constant. Load the flying slider 12 by gradually reducing the amount of space. Accordingly, a slider transfer device that avoids contact or collision between the flying slider 12, particularly the immersion lens, and the optical disk 11 is provided. Since the flying slider 12 approaches the optical disk 11 while moving up and down, the possibility of contact or collision is reduced. This is shown in FIG. 7, and it can be seen that the possibility of contact or collision is lower than in the example shown in FIG.
[0031]
In the embodiment of the present invention, the laser interference type displacement meter 17 is used to detect the surface shake or the gap, but other known displacement methods using an optical lever method or a capacitance method are used. Similar results can be obtained using a meter.
[0032]
【The invention's effect】
As described above, the present invention detects the amount of surface vibration of the disk, and controls the amount of slider movement so that the distance between the disk and the slider becomes the target distance based on the amount of surface vibration. The slider moves closer to the disk while moving up and down in the same way as the surface runout. Therefore, the possibility that the slider contacts or collides with the disk is reduced, and the reliability as the information recording / reproducing apparatus is improved.
[0033]
The present invention is particularly effective when used for a flying slider equipped with a solid immersion lens that requires a small flying height for high-density recording.
[Brief description of the drawings]
FIG. 1 is a diagram showing an embodiment of a slider transfer device according to the present invention.
FIG. 2 is a view showing another embodiment of the slider transfer device according to the present invention.
FIG. 3 is a diagram cited for explaining the operation of the embodiment shown in FIG. 1;
4 is a diagram cited for explaining the operation of the embodiment shown in FIG. 2; FIG.
FIG. 5 is a diagram showing a schematic structure of a conventional slider transfer device.
FIG. 6 is a diagram showing a relationship between a slider and a surface runout of a conventional slider transfer device on a time axis.
FIG. 7 is a diagram showing a relationship between a slider and a surface runout of the slider transfer device according to the present invention on a time axis.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 11 ... Optical disk 12 ... Flying slider 13 ... Suspension 14 ... Moving Z stage 15 ... Loading control circuit 16 ... Position correction coil 17 ... Laser interference type displacement meter 21 ... Magnetic material piece

Claims (3)

In a slider transfer device for transferring a slider equipped with information reading or writing means to a predetermined position in a direction close to the disk,
A surface shake amount detecting means for detecting a surface shake amount of the disk;
Transport control means for controlling the transport amount of the slider based on the detected surface deflection amount so that the distance between the disk and the slider becomes a target interval ;
The transfer control means includes
Z stage control means for controlling the transfer amount of the Z stage that supports the slider and moves in a direction close to the disk;
And a correction coil control means for controlling a position correction coil for correcting the position of the slider moved by the Z stage based on the surface tilt amount . The position correction coil is provided in the vicinity of the slider, and generates a magnetic field in the axial direction of the coil which is a descending direction of the slider by supplying a direct current.
The Z stage control means sets a position separated from the disk by an arbitrary distance as an initial position, and lowers the slider at a predetermined speed from the initial position toward the disk as the disk rotates.
The correction coil control means sets an initial state in which the slider is balanced with an elastic force of a suspension supporting the slider by a magnetic field generated by passing a current through the position correction coil. In conjunction with this, an alternating current corresponding to the surface vibration is superimposed on a direct current flowing in the position correction coil so that the slider moves while maintaining a certain distance from the surface vibration of the disk. The slider transfer device according to claim 1 , wherein superposition of an alternating current to the position correction coil is stopped when stopped at a position . The slider, the slider transfer device according to claim 1 or 2, characterized in that a flying slider which holds a solid immersion lens which converges the light condensed by the objective lens.

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