JP2001023191A - Recording and/or reproducing device, and recording and/ or reproducing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To control the distance between an optical disk and an objective lens to a fixed value in the condition that they are optically in contact with each other. SOLUTION: An optical pickup 10 is provided with a slider 17, an arm 18, and a pressurization adjustment means 19 for displacing a solid immersion lens(SIL) 14 in a direction for approaching or leaving an optical disk 100, and a processing circuit 16 with a distance control function for constantly maintaining the distance between the SIL 14 and the optical disk 100 by controlling an objective lens displacement means based on a distance detection signal obtained according to the quantity of return light for detecting distance that is obtained by scanning an area on a recessed groove part being extended in a direction that is vertical to a recording track in a region for detecting distance that is provided at the optical disk 100 with a light spot being formed by a laser beam that is emitted from an emission surface 14a of the SIL 14.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recording and / or reproducing apparatus for recording and / or reproducing an information signal on a signal recording medium by condensing a laser beam, and a recording and / or reproducing method.

[0002]

2. Description of the Related Art In recent years, with the development of technology for digitally recording video data such as moving images and still images on a signal recording medium, a large amount of data has been recorded on the signal recording medium. Further, instead of magnetic disks such as floppy disks which have been generally used, optical disks such as magneto-optical disks and phase-change optical disks, which have a high recording density and optically record information signals, are becoming widespread.

In an optical recording / reproducing technique for optically recording / reproducing an information signal on / from a signal recording medium, a reproducing laser beam is condensed on an optical disk which is an optical recording medium.
By monitoring the reflected light, the information signal recorded on the optical disk is read. In this optical recording / reproducing technique, the density of data recorded on the optical disk depends on the spot diameter of the laser light to be focused. That is, the smaller the light spot diameter of the laser beam, the higher the density of recording and reproduction of information signals.

The minimum spot diameter of the laser light condensed by the objective lens has a characteristic that is proportional to the wavelength (λ) of the laser light and inversely proportional to the numerical aperture (NA) of the objective lens. For this reason, in order to increase the recording density, the wavelength of the light source is shortened and the NA of the objective lens is increased.

The numerical aperture (NA) of the objective lens is expressed by the following equation using the incident angle (θ) of the light to be focused and the refractive index (n) of the medium to which the light is focused. Can be.

According to this equation, it is practically impossible to make the numerical aperture (NA) higher than 1 when a focusing path is provided in air where the refractive index (n) is 1. Is shown.

In recent years, as a method of increasing the numerical aperture (NA), a solid immersion lens (Solid Immersion Lens, which is an optical lens) is provided between an objective lens and an optical disk.
A technique of irradiating a laser beam onto an optical disc via the solid immersion lens with an SIL interposed therebetween has been proposed. For example, Terris et al., Appl. Phys. L
ett. 65 (4), p388-p390, 25 July, 1994, and Terris et a
l., Appl. Phys. Lett, 68 (2), p141-p143, 8 January, 1996
Discloses the technique.

In this technique, the distance between the solid immersion lens and the optical disk is shortened, and the thickness of the air layer interposed between the solid immersion lens and the optical disk is reduced as much as possible. Specifically, the distance between the solid immersion lens and the optical disk is set to be equal to or less than the wavelength used by the laser light. As a result, there is no optical air layer between the solid immersion lens and the optical disc, and the solid immersion lens and the optical disc are in optical contact with each other, and the numerical aperture (N
It is possible to make A) 1 or more. For example,
The distance between the solid immersion lens and the optical disk is at most 100 nm or less, preferably 50 nm.
It has been proposed to be on the order of magnitude.

The solid immersion lens is
For example, it is mounted on a slider, maintains the above-mentioned distance between the optical disk and the optical disk, and is supported by being floated on the optical disk. The slider forms an air layer between the optical disk and the optical disk by rotation of the optical disk, and floats and supports the mounted solid immersion lens on the optical disk rotated in such a manner. For example,
The slider has a groove formed on the surface facing the optical disk, and the floating amount of the solid immersion lens with respect to the optical disk is set to a predetermined amount.

[0010]

By the way, when the numerical aperture is 1
In the case of exceeding the above, unless the control for sufficiently reducing the thickness of the air layer is performed, the intensity of the laser beam focused on the signal recording surface of the optical disk is reduced, thereby deteriorating the recording accuracy and the reproduction signal. I will. That is, for example, as described above, unless the distance between the solid immersion lens and the optical disk is set to 100 nm or less, preferably about 50 nm, the recording accuracy and the reproduction accuracy deteriorate.

When the optical disk is driven at a constant rotation speed, the linear velocity changes as the optical disk moves in the radial direction. Therefore, when the solid immersion lens is mounted on the slider as described above, and the distance between the solid immersion lens and the optical disk is maintained so as to be in an optical contact state, in the radial direction of the optical disk. The linear velocity for the slider changes. In this case, in the radial direction of the optical disk, the thickness of the air layer formed between the optical disk and the solid immersion lens is not constant, and the shape is formed by, for example, providing a groove on the surface of the slider facing the optical disk. Even if optimized, the flying height cannot be kept uniform when the optical disk is moved in the radial direction.

Accordingly, the present invention has been made in view of the above-described circumstances, and has a recording and / or recording method capable of setting a predetermined distance between an optical disc and an optical lens for condensing a laser beam on the optical disc. Another object is to provide a reproducing apparatus and a recording and / or reproducing method.

[0013]

According to the present invention, a recording and / or recording method according to the present invention is provided.
Or, the reproducing apparatus, in order to solve the above-described problem, an optical lens in which the laser light is incident from the incident surface, and the emission surface for emitting the laser light to the signal recording medium is optically contacted with the signal recording medium, An optical lens displacing means for displacing the optical lens in a direction of coming and going with respect to the signal recording medium; and a concave groove portion extending in a direction perpendicular to the recording track in a distance detection area provided in the signal recording medium. Return light detecting means for detecting the quantity of return light for distance detection obtained by scanning over the distance detection pattern with a light spot formed by the laser light emitted from the emission surface; Distance control that maintains the distance between the optical lens and the signal recording medium by controlling the optical lens displacement means based on a distance detection signal obtained according to the amount of the return light for distance detection. And a stage.

A recording and / or reproducing apparatus having such a configuration is provided with a distance detecting pattern formed as a groove extending in a direction perpendicular to a recording track in a distance detecting area provided on a signal recording medium. The upper surface is scanned by a light spot formed by the laser light emitted from the emission surface of the optical lens whose emission surface is in optical contact with the signal recording medium, and the light amount of the distance detection return light is returned. An optical lens displacement that is detected by the light detection means and is displaced by the distance control means in a direction of moving toward and away from the signal recording medium based on a distance detection signal obtained according to the amount of the return light for distance detection. The means is controlled to keep the distance between the optical lens and the signal recording medium constant.

Thus, the distance between the optical lens and the signal recording medium is kept constant while keeping the optical lens in optical contact with the signal recording medium.

According to the recording and / or reproducing method of the present invention, in order to solve the above-mentioned problem, an incident surface on which a laser beam is incident and an exit surface for emitting the laser beam to a signal recording medium are formed. The optical lens is brought into optical contact with the signal recording medium, and a distance detection pattern formed as a groove extending in a direction perpendicular to the recording track in a distance detection area provided in the signal recording medium. Is scanned by a light spot formed by the laser light emitted from the emission surface to detect the amount of the return light for distance detection, and based on the distance detection signal obtained according to the amount of the return light for distance detection, The lens is displaced in the direction of coming and going with respect to the signal recording medium to keep the distance between the optical lens and the signal recording medium constant.

Thus, the distance between the optical lens and the signal recording medium is kept constant while keeping the optical lens in optical contact with the signal recording medium.

[0018]

Embodiments of the present invention will be described below in detail with reference to the drawings. Although the embodiment is a preferred specific example of the present invention, various technically preferable limitations are given. However, the scope of the present invention is not limited to the embodiment unless otherwise specified. However, the present invention is not limited to the mode shown by.

In this embodiment, a recording and / or reproducing apparatus according to the present invention is applied as an optical disk apparatus for recording and reproducing an information signal on a signal recording medium by condensing a laser beam by an optical pickup. is there.

As shown in FIG. 1, an optical pickup 10 included in an optical disk device includes a light source 11, a beam splitter 12, an objective lens 13, a solid immersion lens (SIL) 14, and a light detecting means 1.
5 and a processing circuit 16. The optical pickup 10 includes a slider 17 and an arm 18 as holding means for the solid immersion lens 14. The optical pickup 10 includes a pressing force adjusting unit 19 that controls a load on the slider 17 as a unit that controls a distance between the solid immersion lens 14 and the optical disk 100.

In the optical pickup 10, the slider 17, the arm 18, and the pressure adjusting means 19 have a function as an optical lens displacing means for displacing the solid immersion lens 14 in a direction in which the solid immersion lens 14 approaches and separates from the optical disc 100. The light detection means 15 emits light from the emission surface 14 a of the solid immersion lens 14 on a distance detection pattern formed as a concave groove extending in a direction perpendicular to the recording track in a distance detection area provided on the optical disc 100. The processing circuit 16 has a function as a return light detecting unit that detects the amount of return light for distance detection obtained by scanning with a light spot formed by the laser beam formed by the laser beam. The above-described optical lens based on a distance detection signal obtained according to the amount of return light for distance detection. Position controlling means functions as a distance control means for maintaining the distance between the solid immersion lens 14 and the optical disc 100 at a constant.

The optical pickup 10 having such a configuration is provided in an optical disk device and records and reproduces information signals on and from an optical disk 100 as a signal recording medium. The optical disk 100 is, for example, a magneto-optical disk on which information signals are recorded magneto-optically. Optical disk 1
00 is easily formed by, for example, injection molding, but is not limited to this. For example, it may be formed by using glass or aluminum as a substrate.

[0023] The optical disc 100, as shown in FIG. 2, a data area D _A where data is recorded, the header portion of the data area D _A, servo information for the optical disc apparatus performs a tracking servo and the like recorded a servo region D _S being is formed. One recording track in the data area D _A and the servo area S _A constitutes a sector. Incidentally, in FIG. 2 shows the manner in which the data area to a portion of the optical disc 100 D _A and the servo area S _A is formed, in fact entire data area D _A and a servo area S _A of the optical disc 100 is Is formed.

[0024] servo area S _A, the tracking information and data address information used for tracking servo are recorded. The groove portion constituting the distance detection pattern is formed in the servo area S _A. Hereinafter, the region in the servo area S _A of the concave groove portion is formed in that distance detecting area.

FIG. 3 shows a distance detecting area of the servo area S _A shown in detail in section _A in FIG. As shown in FIGS. 3A and 3B, a plurality of concave grooves (concave grooves) 100a extending in a direction perpendicular to the recording tracks of the optical disc 100 are formed in the distance detection area. A distance detection pattern is formed. The groove depth of the concave groove portion 100a is a predetermined depth. For example, the groove depth of the concave groove portion 100a is selected to be about 1/8 of the wavelength λ of the laser light emitted from the light source 11. In addition, each groove 100a is located within the distance detection area.
The optical disks 100 are arranged at a predetermined pitch (spatial frequency) in the rotation direction.

The optical pickup 10 has a groove 100a.
The solid immersion lens 14 is displaced toward and away from the optical disc 100 in accordance with a change in the amount of return light for distance detection obtained when the light spot is scanned over the distance detection area in which is formed. Then, the distance between the solid immersion lens 14 and the optical disk 100 is controlled to be maintained as an optimum distance. Control of the distance between the solid immersion lens 14 and the optical disc 100 based on the detection of the concave groove 100a will be described later.

The light source 11 in the optical pickup 10 for recording and reproducing information signals by condensing a laser beam on the optical disc 100 described above is a laser light source for emitting a laser beam. The light source 11 is controlled by a light source driving unit (not shown) to have a predetermined laser power and emit a reproducing laser beam or a recording laser beam. Further, the laser power of the light source 11 is set to a predetermined power when scanning over the distance detection area with the light spot.

The laser light emitted from the light source 11 is
The light passes through the beam splitter 12 and enters the objective lens 13. The laser is converged and emitted toward the solid immersion lens 14 by the objective lens 13.

The solid immersion lens 14 is formed in a substantially hemispherical shape that is convex on the incident side of the laser beam L. The solid immersion lens 14 has a spherical surface portion as an incident surface 14b on which the laser light L is incident, and a flat surface portion for transmitting the laser light L incident from the incident surface 14b to the optical disc 100.
The light exit surface 14a faces the optical disc 100.

The solid immersion lens 14
Means that the distance between the emission surface 14a and the optical disc 100 is 2
It is arranged to be less than or equal to 00 nm. As a result, there is no optical layer between the solid immersion lens 14 and the optical disc 100, and the solid immersion lens and the optical disc 100 are in optical contact with each other. The solid immersion lens 14 has a numerical aperture of 1 or more.

The solid immersion lens 14 and the above-mentioned objective lens 13 constitute a two-group lens for condensing the laser light emitted from the light source 11 on the optical disk 100.

Further, the solid immersion lens 14
Are mounted on the slider 17. Slider 17
Causes the solid immersion lens 14 to float above the rotated optical disk 100 via an air layer. That is, an air layer is formed by rotation of the optical disc 100 between the air layer forming surface 17a of the slider 17 facing the optical disc 100 and the optical disc 100, and the solid immersion lens 14
By being integrated with the optical disk 7, the optical disk 7 is levitated and supported on the rotating optical disk 100.

When the solid immersion lens 14 is thus floated on the optical disc 100,
As described above, the distance from the optical disc 100, that is, the flying height is 200 nm or less, and the optical disc 100
Is brought into an optically contacted state with respect to.

The slider 17 is supported by an arm 18. The flying height of the slider 17 is determined by the load applied to the air layer forming surface 17a via the arm 18, the rigidity of the air layer, and the like.

The pressing force adjusting means 19 moves the arm 18 with respect to the slider 17 so that the arm
This is a load applying means for applying a load via the. By controlling the load on the slider 17 by the pressing force adjusting means 19, the flying height of the slider 17 is controlled, and the distance between the solid immersion lens 14 and the optical disc 100 in an optical contact state is controlled. The pressurizing force adjusting means 19 generates a distance detection signal corresponding to the light amount of the distance detection return light reflected on the emission surface 14a of the solid immersion lens 14 obtained by the processing circuit 16 when the light spot is scanned in the distance detection area. , The load on the slider 17 is changed. Thus, the distance between the solid immersion lens 14 and the optical disc 100 is controlled. Details of the distance control between the solid immersion lens 14 and the optical disc 100 based on a distance detection signal corresponding to the amount of return light for distance detection reflected on the emission surface 14a of the solid immersion lens 14 obtained in the processing circuit 16 Will be described later.

Here, the solid immersion lens 14
The relationship between the distance between the optical disk 100 and the laser beam emitted from the emission surface 14a of the solid immersion lens 14 will be described.

A numerical aperture larger than 1 is realized by the objective lens 13 and the solid immersion lens 14 because:
Only when the solid immersion lens 14 and the optical disk 100 are in optical contact.

For example, when the solid immersion lens 14 moves away from the optical disc 100 within the range of the optical contact state, the ratio of the laser light which is not emitted from the emission surface 14a but reflected on the emission surface 14a is changed. Increase rapidly. Further, when the solid immersion lens 14 moves away from the optical disc 100 beyond the range where such optical contact is made, the laser beam is almost completely reflected (total reflection) on the emission surface 14a.

That is, as shown in FIG. 4, the solid immersion lens 1
As the distance (δ) between the optical disk 100 and the optical disk 100 increases, the amount of the distance detection return light, which is the return light reflected on the emission surface 14a, increases. As shown in FIG. 4, the solid immersion lens 14 and the optical disc 1
When the horizontal axis represents the distance (δ) and the vertical axis represents the light amount of the distance detection return light, the distance between the distance (δ) between 00 and the light amount of the distance detection return light is There is a relationship as a function that is convex. When the solid immersion lens 14 is further moved away from the optical disc 100, the light amount of the return light for distance detection does not increase and remains substantially constant.

On the other hand, as shown in FIG.
The power of the laser beam above 0 (board surface power) shows the opposite tendency in relation to the amount of the return light for distance detection. Therefore, in the state where optical contact is made,
As the distance (δ) between the solid immersion lens 14 and the optical disk 100 increases, the power of the disk decreases.

The relationship between the distance between the solid immersion lens 14 and the optical disk 100 and the laser light emitted from the emission surface 14a of the solid immersion lens 14 have the above-described relationship.

Therefore, the solid immersion lens 14
If the distance between the disk and the optical disc 100 fluctuates,
In some cases, the power of the disk surface fluctuates, making it impossible to record or reproduce information signals on the optical disk 100. When the slider is used, the variation in the distance between the solid immersion lens 14 and the optical disc 100 occurs, for example, when the linear velocity in the radial direction of the optical disc 100 is not constant.

From the above, the optical pickup 1
In the case of 0, it is necessary to keep the distance between the solid immersion lens 14 and the optical disc 100 constant so that a light spot having a predetermined laser power is formed on the optical disc 100. Therefore, the optical pickup 10 uses the optical spot with the predetermined laser power to
The force applied to the slider 17 is controlled by the pressing force adjusting means 19 so that the distance between the solid immersion lens 14 and the optical disc 100 is kept constant so that the solid immersion lens 14 is formed on the zero. The load applied to the slider 17 by the pressure adjusting unit 19 is based on a distance detection signal obtained when the light spot is scanned over the distance detection area detected by the processing circuit 16. Details will be described later.

The laser beam converged by the objective lens 13 is supplied to the slider 1 by the pressing force control means 19 in this manner.
When a load is applied to the optical disk 7, the light is condensed on the optical disk 100 via the solid immersion lens 14 which is floated in a fixed amount on the optical disk 100.

The laser light condensed by the solid immersion lens 14 and irradiated on the optical disc 100 is
As return light reflected on the optical disc 100,
The light is incident on the beam splitter 12 via the solid immersion lens 14 and the objective lens 13. At the time of reproduction, return light reflected on the optical disk 100 (hereinafter, referred to as data modulation return light) is modulated by data recorded on the optical disk 100.

A reflection surface is formed on the beam splitter 12, and the return light for distance detection and the return light for data modulation are
The light is reflected toward the light detecting means 15 by this reflecting surface.

The light detection means 15 outputs a light detection signal corresponding to the return light. The light detecting means 15 detects the light amount of the return light for distance detection when the area for distance detection is scanned by the light spot. In this case, the light detecting means 1
The light amount of the return light for distance detection detected at 5 changes in response to the solid immersion lens 14 crossing over the concave groove 100a. The light detection unit 15 outputs a light detection signal to the processing circuit 16.

The processing circuit 16 performs various kinds of signal processing on the input light detection signal. Further, the processing circuit 16 detects a distance detection signal corresponding to the distance detection return light when the distance detection area is scanned by the light spot, and adds a distance control signal based on the distance detection signal. Output to the pressure adjusting means 19.

The optical pickup 10 operates as follows based on the distance detection signal.
4 and the optical disc 100 are controlled.

The grooves 100a are formed at a predetermined pitch in the rotation direction of the optical disc 100, as described above. As the solid immersion lens 14 traverses the concave groove 100a, the distance between the emission part where the laser light is actually emitted from the emission surface 14a of the solid immersion lens 14 and the optical disc 100 changes at a constant cycle. In the solid immersion lens 14, the emission section is generally located at a substantially central portion of the emission surface 14a.

[0051] For example, as shown in FIG. 5, the distance between the exit portion 14a ₁ and the optical disc 100 of the laser beam with respect to the bottom surface 100a ₁ of the distance [delta] _A or groove portion 100a relative to the bottom surface 100a ₁ of the recessed groove portion 100a The distance δ _B is changed to the surface that is made to be convex, that is, the surface 100 b provided adjacent to the concave groove portion 100 a.

Therefore, the light amount of the return light for distance detection obtained when the light spot condensed by the solid immersion lens 14 crosses the region for distance detection changes according to such a change in distance, and is constant. Is detected as a distance detection signal having an amplitude of That is, the light amount of the return light for distance detection includes the refractive index of the solid immersion lens 14, the numerical aperture (NA), the configuration and the refractive index of the optical disc 100, the wavelength of the laser light emitted from the light source 11, and the solid immersion lens 14. Optical disk 100
The distance between the distance is to be determined by such as emission section 14a ₁ and the optical disc 100 of the solid immersion lens 14 is one of the factors determining the amount of the thus distance detecting return light between However, since it changes as the groove 100a crosses, the amount of the return light for distance detection changes accordingly and is detected as a distance detection signal having a constant amplitude.

Further, the frequency of the distance detection signal obtained in this manner is different from that of the groove 100 in the distance detection area.
Since a is formed at a predetermined pitch, it corresponds to the pitch and the linear velocity.

The processing circuit 16 obtains a distance detection signal having a predetermined frequency corresponding to the pitch of the groove 100a in a signal obtained by scanning the solid immersion lens 14 on the optical disk 100, and detects the distance. Based on the signal amplitude, the distance control signal is applied to the pressing force adjusting means 19.
Output to That is, the amplitude of the distance detection signal obtained when the distance detection area is scanned with the light spot is treated as indicating the distance between the solid immersion lens 14 and the optical disc 100, and the solid immersion is performed based on the amplitude of the distance detection signal. Lens 14 and optical disk 10
Controls the distance between 0.

Based on the principle described below based on the amplitude of the distance detection signal, the solid immersion lens 1
4 and the optical disc 100 are calculated.

As described above, when the solid immersion lens 14 and the optical disc 100 are in optical contact with each other, the distance between the solid immersion lens 14 and the optical disc 100 and the light amount of the distance detecting return light are different. Has a certain relationship as shown in FIG.
Therefore, the emission part 14a ₁ of the solid immersion lens 14 and the emission part 14
When the distance δ from the portion opposed to a ₁ is the first distance δ _X , the light amount of the distance detection return light usually indicates the first light amount R _X. A second different from the distance δ _X
If it is a distance [delta] _Y, the light amount of the distance detecting return light will usually denote the second light quantity R _Y. For example, light source 1
In the case where the laser power in 1 may change, such a case cannot be determined uniquely, and such a case will be described later.

[0057] Here, considering the time of crossing the light spot on the groove portion 100a, the light amount of the time of distance detecting return light, by emitting portion 14a ₁ of the solid immersion lens 14 crosses the groove portion 100a It is changed with a certain amplitude. Change in the amount of light in the distance detecting return light, as shown in FIG. 5, the surface of the optical disc 100 which is opposed to the emitting portion 14a ₁ is provided adjacent to the bottom surface 100a ₁ and the groove portion 100a of the groove portion 100a Face 100
It occurs because b is replaced. Therefore, the amplitude of the change in light amount of the distance detecting return light, a light intensity bottom 100a ₁ is light return for distance detection of when it is facing the emitting portion 14a ₁ in the groove portion 100a, groove portions on the emission portion 14a ₁ It indicates the difference from the light amount of the return light for distance detection when the surface 100b adjacent to 100a is opposed.

On the other hand, in an optically contact state,
The relationship between the distance between the solid immersion lens 14 and the optical disc 100 and the amount of return light for distance detection is such that the horizontal axis represents distance (δ) and the vertical axis represents the amount of return light for distance detection. , The relationship is shown as an upwardly convex function. The groove depth of the concave groove 100a is constant and known.

[0059] Since the above as for the difference between the amount of a certain distance detecting return light, the distance between the emitting portion 14a ₁ and the optical disc 100 of the solid immersion lens 14 is uniquely determined. That, in FIG. 4, the first light quantity R _X distance detecting return light is obtained when the emission part 14a ₁ is opposed to the bottom surface 100a ₁ of the groove portion 100a, further, the second light intensity R _{when Y,} emitting portion 14a ₁ is assumed to be of when opposed to the surface 100b that is provided adjacent to the bottom surface 100a ₁ of the groove portion 100a, groove portion 1
Since the groove depth of 00a is constant, the first distance [delta] _X and the second distance [delta] _Y is identified, the distance between the solid immersion lens 14 and the optical disc 100 is specified.
If the surface 100b adjacent to the concave groove portion 100a and the surface of the optical disk 100 are at the same height, the second distance δ _Y is equal to the solid immersion lens 1.
4 and the surface of the optical disc 100.

For example, the relationship between the distance between the solid immersion lens 14 and the optical disk 100 and the amplitude of the amount of return light for distance detection is stored as information in a table or the like, or the relationship is detected by a relational expression. The distance between the solid immersion lens 14 and the optical disc 100 can be directly obtained based on the difference in the amount of the returned light for distance detection.

When reproducing the distance detection area, the laser power of the laser beam is set to a predetermined value.
On the other hand, there is a case where the laser power of the light source 11 changes. In this case, the absolute value of the light amount of the return light for distance detection changes accordingly. However, even in such a case, the difference between the light amounts of the return light for distance detection hardly changes, so that the distance between the solid immersion lens 14 and the optical disc 100 can be specified.

According to the principle described above, the solid immersion lens 14 and the optical disk 10 are determined by the difference in the amount of return light for distance detection detected when the light spot crosses the concave groove 100a indicated by the amplitude of the distance detection signal.
The distance to zero is calculated. The optical pickup 10 includes such a solid immersion lens 14 and the optical disc 1.
A signal for distance control is output to the pressing force adjusting means 19 in accordance with the calculation result of the distance between 00 and 00. The pressing force adjusting means 19 controls the slider 1 based on the distance control signal.
7 is given a load.

The optical pickup 10 having the above-described configuration allows the reproduction laser beam or the recording laser beam having a predetermined laser power to be supplied to the optical pickup 10 by the objective lens 13 and the solid immersion lens 14 during reproduction or recording. The light is condensed on the optical disk 100 and the information signal is written or read to or from the optical disk 100.

The optical pickup 10 controls the slider 17 by the pressing force adjusting means 19 based on a distance detection signal obtained when a light spot is scanned over a distance detection area provided in a servo area of the optical disk 100. Immersion lens 1
4 and the optical disc 100 can be kept constant as the optimum distance.

Thus, even when the linear velocity is not constant in the radial direction of the optical disc 100, the optical pickup 10 keeps the distance between the solid immersion lens 14 and the optical disc 100 constant, and The laser light can be focused on the top. Therefore, the optical pickup 10 can record and reproduce information signals on the optical disc 100 without deterioration.

As described above, the distance between the solid immersion lens 14 and the optical disc 100 can be controlled based on one concave groove 100a formed in the distance detection area. However, a plurality of grooves 1
By performing distance control based on the amount of return light for distance detection obtained when a light spot is scanned over 00a, distance control can be performed with increased reliability. Further, the distance detection signal obtained when the light spot is scanned over the distance detection area in which the plurality of concave grooves 100a are formed at a predetermined pitch has a frequency corresponding to the pitch of the concave grooves 100a. Therefore, by acquiring a specific frequency band in the processing circuit 16, it becomes possible to acquire a distance detection signal used for distance control.

Further, as described above, the optical pickup 10 includes the solid immersion lens 14 and the optical disc 1.
Utilizing the fact that there is a relationship as a function that is convex upward as described above between the distance between 00 and the amount of return light for distance detection, the distance detection distance obtained by traversing the concave groove 100a. The distance between the solid immersion lens 14 and the optical disc 100 is obtained based on the difference in the amount of the returning light. By doing so, even when the laser power of the laser light emitted from the light source 11 changes, the absolute value of the light amount of the distance detection return light changes accordingly, but the distance detection return light does not change. Since the difference in the amount of light does not change, the solid immersion lens 1
4 and the optical disc 100 can be obtained.

Conventionally, an optical component is mounted on an arm that supports an optical lens for condensing a laser beam on an optical disk, and the optical component is irradiated with light, and the return light reflected by the optical component is reflected on the optical component. There is also a technique of controlling a distance between an optical lens and an optical disk based on the distance. However, the optical pickup 10 according to the present embodiment controls the distance between the solid immersion lens 14 and the optical disc 100 based on a change in the amount of return light for distance detection. It has a simpler configuration.

Further, another distance adjusting laser beam which is not used for the reproducing laser beam and the recording laser beam is focused on the optical disk, and the laser beam is focused on the optical disk and the optical disk based on the return light. It is conceivable to control the distance between the optical lens and the optical lens. However, in this case, a separate light source for emitting the laser beam for adjusting the distance is required, and the apparatus becomes complicated. It is also conceivable to split the laser light emitted from one light source. In this case,
The laser power decreases, that is, for example, the laser power required for reproduction cannot be focused on the optical disk, and the laser power cannot be used effectively.

Further, a groove 100a is formed in the distance detecting area of the optical disc 100 at a first pitch and a second pitch different from the first pitch.
With such first and second pitches, the concave groove portion 100a
It is also possible to control the distance between the solid immersion lens 14 and the optical disc 100 based on a distance detection signal obtained when a light spot is scanned in the distance detection area where is formed.

As described above, the optical pickup 10 performs the solid immersion lens operation based on the amplitude of the distance detection signal obtained when the light spot is scanned in each of the distance detection areas where the concave portions 100a are formed at different pitches. By calculating the distance between the optical disk 100 and the optical disk 100, the distance of the solid immersion lens 14 from the optical disk 100 can be controlled more accurately. That is, for example, the optical pickup 10 scans a light spot over a distance detection area in which the concave grooves 100a are formed at the first pitch (hereinafter, referred to as a first distance detection signal). ), It is not possible to perform control with high accuracy based on the second pitch.
By controlling based on a distance detection signal (hereinafter, referred to as a second distance detection signal) obtained by scanning the light spot on the distance detection area where a is formed, it is possible to control with high accuracy. .

Further, the distance between the solid immersion lens 14 and the optical disk 100 can be controlled based on the following principle.

As described above, the optical pickup 10 obtains the distance detection signal by scanning the light spot on the distance detection area where the concave grooves 100a are formed at a certain pitch. When the width of the groove 100a is smaller than the spot diameter of the light spot between the light spot to be formed and the pitch of the groove 100a, that is, when the pitch is short, the amplitude of the light amount change of the return light for distance detection decreases. That is, the relationship is established.

On the other hand, the spot diameter of the light spot formed on the optical disk 100 by being condensed by the solid immersion lens 14 is
The shorter the distance, the smaller the distance between the optical disk 100 and the optical disk 100.

From such a relationship, by changing the distance between the solid immersion lens 14 and the optical disc 100, the light spot is scanned over the distance detecting area where the concave groove 100a is formed at the first and second pitches. Thereby, for example, a distance detection signal as shown in FIG. 6 can be obtained.

FIG. 6 (A) shows a first distance detection signal, and FIG. 6 (B) shows a groove 100a formed by a second pitch which is longer than the first pitch. 2 shows a second distance detection signal obtained by scanning a light spot over the distance detection area. FIGS. 6A and 6B show the solid immersion lens 1.
4 shows distance detection signals obtained at each pitch when the distance L between the optical disk 100 and the optical disk 100 is 50 nm (thin line) and 200 nm (thick line).

When the first distance detection signal shown in FIG. 6A is compared with the result of the second distance detection signal shown in FIG. 6B, the distance between the solid immersion lens 14 and the optical disc 100 is reduced. The result is that the amount of change in amplitude is larger than the amount of change in distance.

This is because the width of the groove 100a formed at the second pitch is sufficiently larger than the spot diameter of the light spot, while the width of the groove 100a formed at the first pitch is small. This is because it is close to the spot diameter of the light spot. That is, when the solid immersion lens 14 is brought into contact with or separated from the optical disc 100 when the light spot is irradiated on the concave groove 100a formed at the first pitch, the length is close to the width of the concave groove 100a. This is because the spot diameter of the light spot changes within the range.

As described above, the solid immersion lens 1
Even if the amount of change in the distance between the optical disk 100 and the optical disk 100 is the same, the amount of change in the amplitude of the first distance detection signal is large, and the amount of change in the amplitude of the second distance detection signal is small.

Accordingly, the first groove and the second pitch are used to obtain the distance detection signal as shown in FIG.
00a is formed on each of the distance detection areas in a state of being in optical contact with each other, by referring to the amplitudes of the first and second distance detection signals obtained by scanning the light spot. The distance between the immersion lens 14 and the optical disc 100 can be calculated. For example, the distance between the solid immersion lens 14 and the optical disc 100 can be calculated based on the difference between the amplitude of the first distance detection signal and the amplitude of the second distance detection signal.

Specifically, when the difference between the amplitude of the first distance detection signal and the amplitude of the second distance detection signal is large,
It can be seen that the solid immersion lens 14 and the optical disc 100 are further separated in a state where the optical contact is made, and the amplitude of the first distance detection signal and the amplitude of the second distance detection signal are different. If the difference is small, the solid immersion lens 14 and the optical disc 1
Since 00 is closer to the state where the optical contact is made, the distance between the solid immersion lens 14 and the optical disk 100 is specifically derived from such a relationship.

Note that, in this case, the groove 1
The determination of the distance detection signal obtained by scanning the light spot on the distance detection area where 00a is formed is performed based on the frequencies corresponding to the first and second pitches.

The optical pickup 10 refers to the amplitudes of the first and second distance detection signals obtained by scanning the light spot on the distance detection area formed by the concave grooves 100a having different pitches. By controlling the distance between the solid immersion lens 14 and the optical disk 100 in this way, even when the laser power of the light source 11 fluctuates, such a fluctuation amount is canceled and the laser power fluctuation is reduced. It is possible to control the distance between the solid immersion lens 14 and the optical disk 100 to be a desired distance without being affected.

Further, for example, the distance between the solid immersion lens 14 and the optical disk 100 and the amplitude of the first and second distance detection signals (or the amplitude of the light amounts of the first and second distance detection return lights) By storing the relation with the difference as information in a table or the like or obtaining the relational expression, the difference between the amplitudes of the detected first and second distance detection signals or the first and second distances is obtained. The solid immersion lens 1 is directly obtained from the difference in the change in the amount of return light for detection.
4 and the optical disc 100 can be obtained.

As described above, the optical pickup 10
The distance between the solid immersion lens 14 and the optical disc 100 can be controlled based on the first and second distance detection signals.

Next, a specific configuration of an optical disk device having the optical pickup 10 will be described.

The optical disk device is configured to magnetically record information signals on a magneto-optical disk.
Specifically, as shown in FIG.
0, spindle motor 31, magnetic head 32, head driving unit 33, RAM (Random Access Memory) 34, signal processing unit 35, interface 36, servo control unit 3
7, a feed motor 38, and a system controller 39.

In this optical disk device, the spindle motor 31, the magnetic head 32, the head drive unit 33, the RA
The M34, the signal processing unit 35, the servo control unit 37, the feed motor 38, and the system controller 39 control the optical pickup
It constitutes recording and / or reproducing means for recording and / or reproducing information signals for 0.

The spindle motor 31 is connected to the optical disk 10
Drive means for rotating 0. The drive of the spindle motor 31 is controlled by a system controller 39 and a servo controller 37, and is rotated at a predetermined rotation speed.
Laser light is emitted from the optical pickup 10 to the optical disc 100 that is rotated by the spindle motor 31.

The optical pickup 10 irradiates the optical disc 100 rotated by the spindle motor 31 with laser light, and reads out information signals from the optical disc 100 based on the return light (data modulation return light). . Further, the optical pickup 10 is used for the optical disc 1.
The recording track No. 00 is supported movably in the vertical direction, and is driven by a feed motor 38.

The driving of the magnetic head 32 is controlled by the head driving unit 33 to apply a magnetic field to the optical disk 100. By applying a magnetic field to the optical disk 100 by the magnetic head 32, an information signal is written to a signal recording layer of a portion of the optical pickup 10 where the laser is irradiated. The head drive unit 33 controls the magnetic field modulation of the magnetic head 32 according to the information signal.

[0092] The signal processing unit 35 is configured to perform various signal processing. The signal processing unit 35 is, specifically,
The information signal reproducing system includes a signal demodulator and an error correction circuit, and the information signal recording system includes a signal modulator and the like. The RAM 34 is storage means for storing data, and is used, for example, as a working memory of the signal processing unit 35.

At the time of reproduction, the signal processing unit 35 demodulates the signal read from the optical disk 100 by the optical pickup 10 using a signal demodulator to demodulate the signal.
Then, error correction is performed by a correction circuit.

On the other hand, when recording, the signal processing unit 35
The data is modulated by the signal modulator and output to the head driving unit 33. The head driving unit 33 controls the driving of the magnetic head 32 as described above based on the modulation signal obtained by modulating the data.

The interface 36 transmits and receives data to and from an externally connected electronic device. The externally connected electronic device is, for example, an external computer.

For example, when a reproduction operation is being performed in the optical disk device, a reproduction signal processed by a signal demodulator and an error correction circuit of the signal processing unit 35 is transmitted to an external computer via the interface 36. .

The servo control unit 37 includes the optical pickup 1
The servo control of a lens driving unit such as a biaxial actuator for holding the second group lens at 0 is performed in the focusing direction and the tracking direction. Here, the second group lens includes the objective lens 13 and the solid immersion lens 14 as described above.

The servo controller 37 performs servo control on a feed motor 38 for feeding the optical pickup 10. Further, the servo control unit 37 performs servo control on the spindle motor 31 that rotates the optical disc 100. The servo control section 37 performs the above-described servo control of each section based on a control signal from the system controller 39.

The system controller 39 controls each part constituting the optical disk device. As described above, the system controller 39 has a function of outputting a control signal to the servo control unit 37 to control the driving of each drive unit, as described above.

In the optical disk device configured as described above, the operation of reproducing the information signal from the optical disk 100 is performed by a signal processing unit for the signal read by the optical pickup 10 from the optical disk 100 rotated by the spindle motor 31. The signal demodulator 35 demodulates the signal, and the correction circuit corrects the error. Then, the reproduction signal subjected to such signal processing is transmitted to an externally connected electronic device via the interface 36, for example.

Regarding the operation of recording an information signal on the optical disk 100, the optical disk device irradiates the optical disk 100 rotated by the spindle motor 31 with a recording laser beam having a predetermined output from the optical pickup 10. At the same time, the magnetic head 32 is driven by the head driving unit 33 based on the modulated signal obtained by modulating the information signal by the signal modulator of the signal processing unit 35. The optical disk 100 is modulated by the magnetic field modulation of the magnetic head 32.
The magnetization direction of the recording layer is changed, and an information signal is recorded.

Then, the optical disk device is an optical disk 1
Even if the linear velocity is not constant in the radial direction of 00, the laser pickup is focused on the optical disc 100 by keeping the distance between the solid immersion lens 14 and the optical disc 100 constant by the optical pickup 10. Can be done. Therefore, the optical disk device
Recording and reproduction of an information signal with respect to the optical disc 100 can be performed without deterioration.

The operation of the solid immersion lens 14 is not limited to the operation performed by the slider 17. FIG. 8 shows another configuration example of the optical lens displacement means for displacing the solid immersion lens 14.

The optical pickup 10 shown in FIG.
Is substantially the same as the optical pickup 10 shown in FIG. 1 except that the solid immersion lens 14 is held on the optical disc 100 by an actuator 40 instead of a slider. The same components as those of the optical pickup 10 shown in FIG. 1 are denoted by the same reference numerals in FIG. 8, and description thereof will be omitted.

As shown in FIG. 8, the actuator 40 and the actuator driver 20 constitute an optical lens displacement means.

The actuator 40 has the solid immersion lens 14 mounted thereon, and is supplied with a driving current to move the solid immersion lens 14 toward and away from the optical disc 100. This actuator 4
Reference numeral 0 includes a holding portion 41 of the solid immersion lens 14 and a coil winding portion 42.

The holding portion 41 is formed in a substantially flat plate shape, and the outer peripheral portion on the side facing the solid immersion lens 14 is fitted into a lens mounting opening formed near the center.

The coil winding section 42 is formed in a substantially cylindrical shape, and the holding section 41 is formed inside. The coil is wound around the coil winding section 42 so as to be positioned around the optical axis of the solid immersion lens 14.
The actuator 40 has a magnet disposed on the outer periphery of the coil winding section 42.

The actuator 40 thus configured
Is supplied with a driving current to the coil by the actuator driver 20, and the solid immersion lens 14
Is displaced in the direction of coming and going with respect to the optical disc 100.

The actuator driver 20 controls the distance between the solid immersion lens 14 and the optical disk 100, similarly to the movement control mechanism including the slider 17 and the pressure adjusting means 19 described above.

That is, the distance control signal obtained in the processing circuit 16 is input to the actuator driver 20. As described above, the distance control signal is a solid immersion obtained based on the amplitude of the distance detection signal obtained by scanning the light spot on the distance detection area where the concave grooves 100a are formed at a predetermined pitch. The signal is a signal corresponding to the distance between the lens 14 and the optical disc 100.

As described above, the solid immersion lens 14 and the optical disk 1 are moved by the optical lens displacement means having the actuator 40 and the actuator driver 20.
The distance to 00 is kept constant as the optimal distance.

Therefore, the optical pickup 10 is constructed by the above-described actuator 40 and actuator driver 2.
0, the distance between the solid immersion lens 14 and the optical disc 100 is kept constant even when the linear velocity is not constant in the radial direction of the optical disc 100. The laser light can be focused on the top. Therefore, the optical pickup 10 can perform recording and reproduction of the information signal on the optical disc 100 without deteriorating.

In the above-described embodiment, the optical pickup and the optical disk device for recording and / or reproducing the information signal on the magneto-optical disk have been described. However, the present invention is not limited to this, and can be applied to other optical recording media. For example, the present invention can be applied to an optical pickup and an optical disk device that record and / or reproduce information signals on another optical disk that employs the near-field optical recording technology, for example, a phase-change optical disk.

In the above-described embodiment, the groove 1
The groove depth of 00a is set to about 1/8 of the wavelength λ of the laser light emitted from the light source 11. However, the present invention is not limited to this, and the groove depth of the concave groove portion 100a may be another depth.

[0116]

According to the recording and / or reproducing apparatus of the present invention, a laser beam is incident from an incident surface, and an exit surface for emitting the laser beam to a signal recording medium is in optical contact with the signal recording medium. A lens, an optical lens displacing means for displacing the optical lens in a direction of coming and going with respect to the signal recording medium, and a concave groove extending in a direction perpendicular to the recording track in a distance detection area provided on the signal recording medium. Return light detection means for detecting the amount of distance detection return light obtained by scanning the formed distance detection pattern with a light spot formed by the laser light emitted from the emission surface, and return light detection means Controls the optical lens displacing means based on the reproduction signal obtained according to the amount of the return light for distance detection detected by the distance control to keep the distance between the optical lens and the signal recording medium constant. Means for emitting light to the signal recording medium on a distance detection pattern formed as a concave groove extending in a direction perpendicular to the recording track in a distance detection area provided on the signal recording medium. Scanning by a light spot formed by the laser light emitted from the emission surface of the optical lens whose surface is optically contacted, detecting the amount of return light for distance detection by return light detection means, By controlling the optical lens displacing means for displacing the optical lens in the direction of coming and going with respect to the signal recording medium, based on the distance detection signal obtained according to the amount of the return light for distance detection, The distance to the recording medium can be kept constant.

Thus, the distance between the optical lens and the signal recording medium is kept constant while the optical lens is in optical contact with the signal recording medium.

Further, according to the recording and / or reproducing method of the present invention, an optical lens having an incident surface on which laser light is incident and an emission surface for emitting the laser light to a signal recording medium is formed by a signal recording method. A laser which is brought into optical contact with a medium and emitted from an emission surface on a distance detection pattern formed as a groove extending in a direction perpendicular to a recording track in a distance detection area provided on a signal recording medium. A light spot formed by light is scanned to detect the amount of return light for distance detection, and the optical lens is brought into contact with a signal recording medium based on a reproduction signal obtained according to the amount of return light for distance detection. By controlling the distance between the optical lens and the signal recording medium,
The distance between the optical lens and the signal recording medium is kept constant while the optical lens is in optical contact with the signal recording medium.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of an optical pickup included in an optical disc device according to an embodiment of the present invention.

FIG. 2 is a plan view showing an optical disc on which a data area and a servo area are formed.

FIG. 3 is a diagram showing a part of the above-described servo area, which is a distance detection area in which a concave groove is formed at a predetermined pitch.

FIG. 4 is a characteristic diagram showing a relationship between a distance between a solid immersion lens and an optical disk and a light amount of return light for distance detection.

FIG. 5 is a front view showing a positional relationship between a solid immersion lens and a concave groove formed in a distance detection area provided on the optical disc.

FIG. 6 shows first and second distance detection signals obtained by scanning a light spot on a distance detection area in which concave grooves are formed at the first and second pitches, and is a solid view. FIG. 9 is a characteristic diagram showing a change in a reproduced signal when the distance between the immersion lens and the optical disk is 50 nm and 200 nm.

FIG. 7 is a block diagram illustrating a configuration of an optical disc device according to an embodiment of the present invention.

FIG. 8 is a block diagram illustrating a configuration of an optical pickup in which a solid immersion lens is displaced by an actuator.

[Explanation of symbols]

11 light source, 14 solid immersion lens, 15
Light detection means, 16 processing circuit, 17 slider, 18
Arm, 19 means for adjusting pressure

 ──────────────────────────────────────────────────続 き Continuation of the front page (72) Kenji Yamamoto, Inventor 6-7-35 Kita-Shinagawa, Shinagawa-ku, Tokyo Inside Sony Corporation (72) Inventor Kiyoshi Osato 6-35, Kita-Shinagawa, Shinagawa-ku, Tokyo Sony Corporation F term (reference) 5D118 AA13 BA01 BB02 BF02 BF03 CC06 CC12 CD02 FB09 5D119 AA12 BA01 BB03 DA01 DA05 EA03 FA02 HA31

Claims (16)

[Claims] 1. A recording and / or reproducing apparatus for condensing a laser beam on a signal recording medium and recording and / or reproducing an information signal on the signal recording medium, comprising: a light source for emitting the laser beam; An optical lens in which the laser light is incident from an incident surface and an emission surface for emitting the laser light to the signal recording medium is optically contacted with the signal recording medium; An optical lens displacing means for displacing in the direction of contact and separation; and a distance detection pattern formed as a groove extending in a direction perpendicular to the recording track in a distance detection area provided in the signal recording medium. Return light detecting means for detecting the amount of distance detection return light obtained by scanning with a light spot formed by the laser light emitted from the emission surface; The optical lens displacing means is controlled based on a distance detection signal obtained in accordance with the light amount of the distance detection return light detected by the output means, so that the distance between the optical lens and the signal recording medium is kept constant. A recording and / or reproducing apparatus, comprising: a distance control unit for keeping. 2. The signal recording medium according to claim 1, wherein the signal recording medium is a disk-shaped recording medium having a substantially disc shape, and a rotation operation unit for rotating the disk-shaped recording medium. Is mounted, a slider that floats on the rotating disk-shaped recording medium via an air layer, and a load applying unit that applies a load to the slider in a direction approaching and separating from the disk-shaped recording medium. The recording and / or reproducing apparatus according to claim 1, further comprising: a distance control unit that controls a load applied to the slider by the load applying unit. 3. The actuator, wherein the optical lens displacing means is provided with the optical lens, and is supplied with a driving current to move the optical lens toward and away from the signal recording medium. 2. The recording and / or reproducing apparatus according to claim 1, further comprising an actuator driving unit that supplies the driving current, wherein the distance control unit controls the supply of the driving current to the actuator driving unit. apparatus. 4. The apparatus according to claim 1, wherein said distance control means controls said optical lens displacement means in accordance with an amplitude of a distance detection signal obtained in accordance with a change in the amount of said return light for distance detection. Recording and / or reproducing apparatus. 5. The recording and / or reproducing apparatus according to claim 1, wherein a plurality of the groove portions are arranged at a predetermined pitch in the distance detection area. 6. A first distance detection area in which the concave grooves are arranged at a first pitch in a distance detection area, and a second pitch which is different from the first pitch in a second pitch. There is a second distance detection area in which the concave grooves are arranged, and the distance control means scans the first distance detection area with the light spot and obtains a first distance detection return. In accordance with the amplitude of the first distance detection signal according to the change in the light amount of light and the change in the light amount of the second distance detection return light obtained by scanning the second distance detection area with the light spot. 6. The recording and / or reproducing apparatus according to claim 5, wherein said optical lens displacement means is controlled in accordance with a result of comparison with the amplitude of said second distance detection signal. 7. The optical lens is formed in a substantially hemispherical shape that is convex on the laser light incident side, a spherical part is the laser light incident surface, and a flat part faces the signal recording medium. 2. The recording and / or reproducing apparatus according to claim 1, wherein the light exit surface is used. 8. The recording and / or reproducing apparatus according to claim 1, wherein the numerical aperture of the optical lens is one or more. 9. A recording and / or reproducing method for recording and / or reproducing an information signal on a signal recording medium by converging a laser beam on the signal recording medium, wherein the incident surface on which the laser light is incident And an optical lens having an emission surface for emitting the laser light to the signal recording medium is brought into optical contact with the signal recording medium, and is positioned within a distance detection area provided on the signal recording medium. The distance detection pattern formed as a concave groove extending in the direction perpendicular to the recording track is scanned by a light spot formed by the laser light emitted from the emission surface to detect the amount of distance detection return light. Then, based on a distance detection signal obtained according to the amount of the return light for distance detection, the optical lens is displaced in a direction of coming into contact with or separating from the signal recording medium. A recording and / or reproducing method, wherein a distance between the recording medium and the signal recording medium is kept constant. 10. A disk-shaped recording medium formed in a substantially disc shape as said signal recording medium, said optical lens being mounted thereon, and floating above said rotating disk-shaped recording medium via an air layer. 10. The distance between the optical lens and the disk-shaped recording medium is kept constant by controlling a load applied to the slider in the direction of coming into contact with and separating from the disk-shaped recording medium. Recording and / or reproducing method. 11. A driving current is supplied to the optical lens, and the supply of the driving current to an actuator that moves the optical lens in a direction of moving toward and away from the signal recording medium is controlled by controlling the supply of the driving current. 10. The recording and / or reproducing method according to claim 9, wherein a distance between the optical lens and the signal recording medium is kept constant. 12. The optical lens according to claim 1, wherein the optical lens is displaced in a direction of coming into contact with or separating from the signal recording medium in accordance with an amplitude of a distance detection signal obtained in accordance with a change in the amount of the return light for distance detection. The recording and / or reproducing method according to claim 9, wherein 13. The signal recording medium according to claim 9, wherein a plurality of the grooves are arranged at a predetermined pitch in the distance detection area.
The recording and / or reproducing method as described in the above. 14. The signal recording medium according to claim 1, wherein the first pitch is provided with a first distance detecting area in which the concave grooves are arranged, and the second pitch is different from the first pitch. A light amount of the first distance detection return light obtained by scanning the first distance detection area with the light spot using a second distance detection area in which grooves are arranged. And the amplitude of the distance detection signal according to the change in the light amount of the second distance detection return light obtained by scanning the second distance detection area with the light spot. 10. The recording and / or reproducing method according to claim 9, wherein a displacement between the optical lens and the signal recording medium is kept constant by controlling a displacement of the optical lens according to a comparison result with the optical recording medium. . 15. The optical lens according to claim 1, wherein the optical lens is formed in a substantially hemispherical shape that is convex on an incident side of the laser light, a spherical portion is the incident surface of the laser light, and a flat portion faces the signal recording medium. 10. The recording and / or reproducing method according to claim 9, wherein the light emitting surface is used. 16. The optical lens according to claim 9, wherein the optical lens has a numerical aperture of 1 or more.
The recording and / or reproducing method as described in the above.