JP2003162840A - Optical pickup and recorded information reproducing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To record information in high density and reproduce the recorded information excellently through electromagnetic reactions by generating strong electromagnetic fields in a small area finer than the diffraction limit on a recording medium in a simple configuration. <P>SOLUTION: An optical head 7 has a slider 11 scanning the recording medium 4 and has a metal surface 12 which has a fine gap smaller than the laser beam wavelength, and it generates a local electromagnetic field 19 by the laser beam radiated to the vicinity of the fine gap 12b. A radiating optical system 8 radiates a laser beam to the fine gap 12b of the metal surface 12 and this beam is polarized parallel to the surface of the medium 4 and vertical to the radiation plane. The optical pickup of this invention is composed of the above optical head 7 and the radiating optical system 8. Thus the energy of the laser beam is effectively used to generate a local electromagnetic field and this field is used for recording and reproducing. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical pickup and an information recording / reproducing apparatus capable of recording or reproducing information on a recording medium or both recording and reproducing operations.

[0002]

2. Description of the Related Art Information recording / reproducing apparatuses currently in practical use for recording / reproducing information on / from an optical memory such as an optical disk focus light to a diffraction limit of light determined by the wavelength of light and the numerical aperture of an objective lens. The information is recorded by irradiating the recording medium with the generated laser light and thermally and magnetically modulating the recording layer,
Information is reproduced by detecting the intensity and polarization of reflected light that is modulated by the recording pits that record information. When this information recording / reproducing apparatus is used, the recording density of the optical memory is determined by the diffraction limit of light, and there is a limit to cope with the recent increase in the amount of information surrounding information devices such as computers, There is a demand for a large-capacity optical memory that achieves a recording density that exceeds the diffraction limit of light.

An information recording / reproducing apparatus using so-called near-field light, which records and reproduces information by using near-field light, is promising as such a large-capacity optical memory, for example, JP-A-5-250708. No.
No. 259902, JP-A No. 11-265520, and the like. Near field is different in refractive index 2
Light that enters from one of the two media under total reflection conditions or more is totally reflected at the reflective boundary surface, but there is a region that partially exudes the non-propagating electromagnetic field component beyond the boundary surface. Refers to an area. It is said that this near field exudes only in the vicinity of the opening, which is smaller than the wavelength of the incident light, and has a lateral spread of about the same size as the opening. Therefore, the resolution exceeding the diffraction limit of light can be obtained by reducing the aperture size.

An information recording / reproducing apparatus using this near-field optical probe is a semiconductor laser device (L
D) The laser light emitted from 41 is collimator lens 4
2 becomes parallel light, and this light passes through the polarization beam splitter 43 and the quarter-wave plate 44, and then the objective lens 45
The light is focused by and is irradiated onto the near-field optical probe 46. The near-field optical probe 46 is provided with a truncated cone-shaped protrusion formed of a high-refractive material such as silicon having a higher refractive index than a transparent substrate on a transparent substrate such as a glass substrate. It is composed by coating with a metal such as silver or aluminum. Then, the light condensed by the objective lens 45 is converted into a near-field light of a minute size at the tip of the near-field light probe 46. The recording layer 48 provided on the surface of the recording medium 47 facing the near-field optical probe 46 by the converted near-field light.
It is possible to realize higher density recording than in the case where the information is recorded in and the light is condensed by the objective lens 45. When reproducing the information recorded on the recording medium 47, the recording layer 3
The light reflected from 8 is the objective lens 45 and the quarter-wave plate 44.
After passing through, the light is reflected by the polarization beam splitter 43, condensed by the condenser lens 49 on the photodetector 50, the light intensity is detected by the photodetector 50, and information is reproduced.

[0005]

Generally, in a near-field optical probe for generating near-field light, it is theoretically difficult to make the near-field generation region small and increase the strength at the same time. . In addition, there is a disadvantage in that in order to manufacture the near-field optical probe, a highly accurate processing process and assembly work comparable to the semiconductor process are required.

The present invention solves the above drawbacks and has a relatively simple structure, which generates a strong electromagnetic field in a minute region below the diffraction limit on a recording medium, and records information at high density through electromagnetic interaction there. Another object of the present invention is to provide an optical pickup and an information recording / reproducing apparatus which can reproduce the recorded information in a good condition.

[0007]

An optical pickup according to the present invention is an optical pickup which is disposed in the vicinity of a recording medium and records information on the recording medium by the irradiated light and reproduces the information recorded on the recording medium. The pickup has a metal surface provided on a slider for scanning on a recording medium and provided with a minute gap having a width narrower than the wavelength of the laser beam, and is locally irradiated by the laser beam irradiated in the vicinity of the minute gap. An optical head that generates an electromagnetic field in a region, and a polarization direction of the laser light that irradiates a minute gap on the metal surface of the optical head has an irradiation optical system that is parallel to the recording medium surface and perpendicular to the incident surface. The energy of laser light is efficiently used to generate a localized electromagnetic field, and this electromagnetic field is used to enable high-density recording.

In the above optical head, a minute gap for generating an electromagnetic field in a local region by laser light irradiation is formed by metal members arranged on both sides with a dielectric material thinner than the wavelength of the laser light being irradiated therebetween. A desired minute gap is easily produced.

Further, a member made of a material different from that of the metal member may be disposed in contact with the surface of the metal member sandwiching the dielectric member, which is opposite to the surface in contact with the dielectric member, and the minute gap may be damaged by contact with the recording medium. prevent.

Furthermore, a transparent member having a curved surface on which the laser light is incident is integrated with the surface of the optical head having the minute gap on which the laser light is incident, and the light is condensed in the area of the minute gap. The focused spot of the laser light is made smaller and the energy of the laser light is effectively used.

An information recording / reproducing apparatus according to the present invention has the above-mentioned optical pickup and records information on a recording layer of a recording medium by an electromagnetic field generated in a local area near a minute gap of an optical head. Is recorded with high density.

The light transmitted through the recording medium is detected by a photodetector to reproduce the information recorded in the recording medium, and the light propagating from the recording medium into the optical head is used to scan the optical head. The information detected by the photodetector mounted on the arm or the optical head and recorded on the recording medium is reproduced, and the information recorded at high density is stably reproduced.

Further, a photodetector for detecting the light propagating inside the optical head is provided at a position where it does not intersect with the surface on which the laser beam of the principal ray of the laser beam applied to the optical head is incident, and only the reproduced information is reproduced. Incident light is made incident on the photodetector to improve the S / N of information reproduction.

Further, the wiring for guiding the electric signal from the photodetector mounted on the optical head to the signal processing circuit provided at a place other than the optical head is integrated with the suspension, so that the movement of the suspension is impaired. prevent.

Further, an antireflection film is formed at a portion where the light from the recording medium propagates, passes through the slider of the optical head and is emitted, and the light containing the information of the recording medium is efficiently incident on the photodetector.

[0016]

1 is a block diagram of an information recording / reproducing apparatus of the present invention. As shown in the figure, the information recording / reproducing apparatus 1 is a state in which a circular recording medium 4 having a recording layer 3 made of a phase change material on a transparent substrate 2 such as glass or polycarbonate is rotated by a spindle motor (not shown). Information is recorded on and reproduced from the recording medium 4, and the arm 5
Optical head 7 attached to the suspension via suspension 6
An optical system 8 for irradiating the optical head 7 with laser light for recording and reproduction, and an arm 9 arranged on the transparent substrate 2 side of the recording medium 4 for receiving the scattered light scattered by the recording medium 4. It has a photodetector 10 composed of a diode or the like, and the optical head 7 is arranged in proximity to the recording layer 3 of the rotating recording medium 4 to a distance equal to or less than the wavelength.

The arm 5 supports the optical head 7 via a suspension 6 which stabilizes the flying height of the optical head 7 with respect to the recording medium 4, and positions the optical head 7 on the recording medium 4 by a driving mechanism (not shown). Scan. The optical head 7 has a metal surface 12 made of, for example, gold, silver, aluminum or the like and having a thickness of about 50 to 300 nm on the side surface parallel to the yz plane of the slider 11 made of glass or synthetic resin. The metal surface 12 of the optical head 7 is
As shown in the side view of FIG. 2 and the perspective view of FIG.
The portion close to the recording layer 3 is thinned to form a triangular groove 12
a. The width d of the gap 12b at the end of the triangular groove 12a which is close to the recording layer 3 is formed to be sufficiently small, such as ⅕ of the wavelength of the laser light to be irradiated.

The optical system 8 has a light source 13 composed of a semiconductor laser element arranged on the arm 5, a collimating lens 14 and a concave reflecting mirror 15, and a laser beam 16 having a wavelength of 405 nm emitted from the light source 13 is collimated by the collimating lens 13. Through the concave reflecting mirror 15 and the transmission hole 17 provided in the arm 5, the metal surface 12 of the optical head 7 is focused and irradiated in the vicinity of the minute gap 12b of the metal surface 12 at the end closest to the surface of the recording medium 4. To do. The laser light 16 with which the optical head 7 is irradiated has a polarization direction (electric field vibration direction) in a direction parallel to the surface of the recording medium 4, that is, in the Y direction in FIGS. The irradiation direction is perpendicular to the metal surface 12 when the optical head 7 is viewed from above. The photodetector 10 is attached to the arm 9 that operates in conjunction with the arm 5, and is always positioned on the opposite side of the optical head 7 with the recording medium 4 interposed therebetween.

When information is recorded on the recording medium 4 by the information recording / reproducing apparatus 1, the laser light 16 emitted from the light source 13 is passed through the collimating lens 13, the concave reflecting mirror 15 and the transmission hole 17 provided in the arm 5. Then, as shown in FIG.
The metal surface 12 of the optical head 7 is focused and irradiated in the vicinity 18 of the minute gap 12b closest to the surface of the recording medium 4. When the polarized laser beam 16 is applied to the vicinity 18 of the minute gap 12b of the metal surface 12, the tip portions 12c and 12d of the metal surface 12 that are separated by the minute gap 12b due to the conductivity of the metal.
During this period, the electric field is concentrated and a strong electromagnetic field 19 is locally generated. The electromagnetic field 19 is applied to the recording layer 3 near the optical head 7.
The energy of the electromagnetic field is applied to a minute region below the diffraction of the irradiation laser beam 16 in, that is, a region smaller than when the laser beam 16 is condensed by the objective lens. Therefore, for example, when a phase change material is used for the recording layer 3, the recording layer 3 is locally heated by the energy of the electromagnetic field applied to the recording layer 3 to cause a phase change and a recording mark is formed.
Since the heating of the recording layer 3 is locally performed by the conventional optical memory device in which the laser light 16 is condensed by the objective lens and directly irradiated on the recording medium 4, the recording mark to be formed is smaller than that in the conventional optical memory device. It is possible to perform high-density recording which cannot be achieved.

Further, when reproducing the information recorded on the recording medium 4, the laser beam 16 emitted from the light source 13 is applied to the vicinity 18 of the minute gap 12b of the metal surface 12 of the optical head 7. Electromagnetic field 1 generated by irradiation of this laser beam 16
9 and the recording mark of the recording layer 3 are electromagnetically interacted with each other to undergo a change in intensity and polarization, and then the light propagating to the side that passes through the recording medium 4 is detected by the photodetector 10, whereby the recording medium 4 is detected.
Play the information recorded in.

By configuring the information recording / reproducing apparatus 1 as described above, it is possible to record information on the recording medium 4 and reproduce the information recorded on the recording medium 4 at a higher density than that of the conventional CD or DVD.

In the above description, the case where the phase change material is used as the recording layer 3 of the recording medium 4 has been described, but the recording or reproducing can be performed not only by the phase change material but by locally applying the energy of the electromagnetic field. Any material may be used as long as it is a material. Further, although the case where the concave mirror 15 is used for the optical system 8 which collects the laser light 16 and irradiates the optical head 7 is described, as shown in the configuration diagram of FIG. Alternatively, the laser light 16 may be condensed and applied to the optical head 7.

Further, the case where the triangular groove 12a is formed in the metal surface 12 of the optical head 7 and the minute gap 12b is formed at the end portion of the recording medium 4 which is close to the recording layer 3 has been described. (A), a minute slit 12e is formed on the metal surface 12 to form a minute gap 12b having a width equal to or less than the wavelength of the laser beam 16, or as shown in (b), Square groove 12f at the end near the recording layer 3
Alternatively, as shown in (c), the circular groove 12g may be formed to form the minute gap 12b.

Further, as shown in the perspective view of FIG. 7 and the side view (a) of FIG. 8, gold or silver is formed on the XZ plane of the side surface of the slider 11 which is orthogonal to the side surface of the optical head 7 on which the laser light 16 is incident. , A metal film 22 such as aluminum and a dielectric film 23 such as silicon oxide or silicon nitride are alternately deposited to form a laser beam 16
The minute gap 12b may be formed on the metal surface 12 of the YZ plane on which is incident. In this case, since the width d of the minute gap 12b can be controlled by the thickness of the dielectric film 23, fine processing of the metal surface 12 is not required as compared with the case where the minute gap 12b is formed by a groove, and the minute gap 12b is not required. 12b can be easily manufactured and, for example, the minute gap 1 is formed.
In the case where the width d of 2b is formed to be 0.1 μm or less, the minute gap 12 having a predetermined width d can be manufactured with high accuracy.

Further, as shown in FIG. 8B, a dielectric layer 24 may be laminated on the metal film 22 deposited outside the dielectric film 23. In the optical head 7 in which the dielectric layer 24 is formed on the outer surface of the metal film 22 as described above, when the recording medium 4 is rotated and scanning is performed by the optical head 7, surface deviation of the recording medium 4 or the optical head is caused. When the optical head 7 comes into contact with the surface of the recording medium 4 due to the tilt of the optical head 7, the dielectric layer 24 of the optical head 7 comes into contact with the recording medium 4 as shown in FIG.
Since the metal surface 12 and the minute gap 12b need not come into contact with the recording medium 4, it is possible to prevent the portion of the minute gap 12b from being damaged. Therefore, the durability of the optical head 7 can be improved.

Further, various grooves, the metal film 22 and the dielectric film 2 are formed.
As shown in the configuration diagram of FIG. 10 and the perspective view of FIG. 11, the surface of the optical head 7 on which the laser beam 16 of the optical head 7 having the minute gap 12b formed by alternately depositing 3 is formed of glass or transparent resin. The transparent member 25 having a spherical surface on which the laser light enters is provided, and the laser light 16 is transmitted through the transparent member 25.
May be incident in the vicinity of the minute gap 12b.
When the spherical surface of the transparent member 25 is, for example, a 1/4 spherical surface, and the laser light incident on the spherical surface is made incident so that the wavefront thereof substantially coincides with the spherical surface, the case where light is condensed only by the concave reflecting mirror 15 Also, the numerical aperture can be increased by the refractive index of the transparent member 25, and the minute gap 1 of the optical head 7 can be increased.
It is possible to reduce the size of the focused spot incident near 2b. Therefore, it is possible to generate a more localized electromagnetic field with a high power density in the minute gap 12b, and it is possible to further improve the recording density.

In the above description, the recording medium 4 provided with the recording layer 3 on the transparent substrate 2 is used, and when the information recorded on the recording medium 4 is reproduced, the light transmitted through the recording medium 4 is detected and the recorded information is recorded. Although the case of reproducing is explained, as shown in the configuration diagram of FIG. 12, in the case of the recording medium 4a in which the metal film 30 such as gold, silver or aluminum is provided between the transparent substrate 2 and the recording layer 3, the recording medium 4a is also used. It is possible to reproduce by using the reflected light from 4a. An information recording / reproducing apparatus 1a for recording information on the recording medium 4a and reproducing the recorded information is, as shown in FIG. 12, provided with a photodetector 10 on an arm 5 to which an optical head 7 is mounted via a suspension 6. The configuration is exactly the same as that of the information recording / reproducing apparatus 1 except that it is provided so as to face the optical head 7. The photodetector 10 is connected to the amplification circuit of the signal processing circuit by the wiring 31 provided along the arm 5.

In this information recording / reproducing apparatus 1a, a recording medium 4a
When information is recorded on the recording medium, the information recording / reproducing apparatus 1 records information on the recording medium 4 in exactly the same operation. When reproducing the information recorded on the recording medium 4a, the laser light 16 emitted from the light source 13 is applied to the vicinity of the minute gap 12b on the metal surface 12 of the optical head 7. The electromagnetic field 19 generated by the irradiation of the laser beam 16, the recording mark of the recording layer 3, and the light reflected from the recording medium 4 after being changed in intensity and polarization due to electromagnetic interaction propagate to the inside of the optical head 7. The intensity of the propagated light is detected by the photodetector 10 provided on the arm 5, and the information recorded on the recording medium 4a is reproduced. By providing the photodetector 10 on the arm 5 to which the optical head 7 is attached via the suspension 6 as described above, when the optical head 7 scans the recording medium 4a, the photodetector 10 is connected to the optical head 7. Since they move in synchronization, the scanning mechanism of the optical head 7 and the photodetector 10 can be simplified.

When the reproducing light reflected by the recording medium 4a is transmitted through the optical head 7 and detected by the photodetector 10, a minute film formed by alternately depositing a metal film 22 and a dielectric film 23 is formed. When the optical head 7 having the gap 12b is used, the minute gap 1 of the optical head 7 is reflected by the concave reflecting mirror 15.
Part of the light condensed and irradiated in the vicinity of 2b is recorded on the recording medium 4
It is reflected by the surface of a or is reflected and scattered by the side surface of the metal film 22 and propagates radially. On the other hand, the minute gap 12n
The local electromagnetic field generated by being focused / irradiated in the vicinity of is modulated by the recording mark in the recording layer 3 and then reflected spherically around the minute gap 12b.
Scattered. Therefore, when the photodetector 10 is arranged at the position of the central axis which is perpendicular to the wavefront of the focused spot of the laser light focused by the concave reflecting mirror 15 and passes through the position of the highest intensity, the photodetector 10 records The reflected / scattered light from the mark and the light irrelevant to the information to be reproduced are detected together, and the S / N of the reproduction signal is lowered. Therefore,
As shown in FIG. 13, the photodetector 10 is arranged at a position perpendicular to the wavefront of the focused spot of the laser light and not intersecting with the plane passing through the central axis passing through the strongest position, and the light unrelated to the reproduction information is generated. The S / N ratio of the reproduction signal is increased by not receiving the light and detecting only the light including the reproduction signal.

Further, an antireflection film 32 is provided on the emission surface of the transmitted light of the optical head 7 through which the light reflected by the recording medium 4a is transmitted, and internal reflection when the light reflecting the recorded information is emitted from the optical head 7. It is good to prevent light scattering. As the antireflection film 32, for example, glass having a refractive index of 1.5 is used as the material of the slider 11 of the optical head 7, the wavelength of the irradiation laser beam is 405 nm, and the photodetector 10 from the recording mark.
When the principal ray, which is the strongest ray of the light including the reproduction signal propagating toward, is incident on the antireflection film 32 at an incident angle of 45 degrees, it has a thickness of about 105 nm. It may be formed of a magnesium oxide film. By thus providing the optical head 7 with the antireflection film 32,
The amount of light incident on the photodetector 10 can be increased by reducing the internal reflection and scattering when the light reflecting the recorded information is transmitted through the optical head 7, and the detected light intensity signal is converted into an electric signal. After that, the S / N ratio can be improved and good reproduction can be performed.

Further, the photodetector 10 may not be provided on the arm 5 but may be directly provided on the optical head 7 as shown in FIG. By providing the photodetector 10 in the optical head 7 as described above, even when the distance between the arm 5 and the optical head 7 is changed by following the surface wobbling when the recording medium 4a is rotated, Minute gap 12b of optical head 7
The positional relationship between the recording medium 4a and the photodetector 10 can be kept constant, and a stable reproducing operation can be performed.

When the optical head 7 having the minute gap 12b formed by alternately depositing the metal film 22 and the dielectric film 23 is used, the photodetector 10 provided in the optical head 7 reflects from the recording mark. In order to prevent scattered light and light unrelated to information to be reproduced from being detected together with light including a reproduction signal, and to detect only light including a reproduction signal, a photodetector 10 is provided as shown in FIG. It may be provided on the side surface of the optical head 7 which is perpendicular to the surface of the recording medium 4.

When the photodetector 10 is provided in the optical head 7 as described above, if the wiring 31 from the photodetector 10 is connected to the arm 5 separately from the suspension 6, the optical head 7 is scanned on the recording medium 4a. Optical head 7 and recording medium 4
There is a problem in the function of the suspension 6 that keeps the distance from a and the attitude of the optical head 7 constant. To prevent this
As shown in the side view of FIG. 17A and the plan view of FIG.
The wiring 31 of the photodetector 10 is connected to the connecting wiring 33 provided on the suspension 6. By connecting the wiring 31 to the connection wiring 33 provided on the suspension 6 in this way, it is possible to prevent the operation of the suspension 6 from being defective.
It is possible to realize stable scanning of the optical head 7.

Further, as shown in the circuit diagram of FIG. 18, the driving circuit of the semiconductor laser element of the light source 13 is provided with an AC power source 34.
And a DC power supply 36 in parallel with the capacitor 35,
The DC power supply 36 is set so that when the current flowing through the semiconductor laser element of the light source 13 is modulated by the AC power supply 34, the current flowing through the semiconductor laser element is equal to or higher than the threshold current for constantly oscillating. The modulation frequency of the AC power supply 34 is, for example, 30 Mbp for reproducing recorded information.
s (speed of reading 30 megabit data per second)
800MHz, which is much faster than this
The semiconductor laser device is intensity-modulated by setting the frequency to. As a result, even when there is light returning from the vicinity of the boundary between the surface of the optical head 7 and the recording medium 4 to the light source 13, the emission intensity can be kept constant, and stable recording / reproducing operation can be performed.

[0035]

As described above, the present invention has a metal surface provided with a slider for scanning on a recording medium and provided with a minute gap having a width narrower than the wavelength of laser light. The polarization direction of the optical head that generates an electromagnetic field in a local area by the laser light emitted in the vicinity and the polarization direction of the laser light that is emitted to the minute gap on the metal surface of the optical head is parallel to the surface of the recording medium and By configuring the optical pickup with the irradiation optical system that is vertical, the energy of the laser light is efficiently used to generate a localized electromagnetic field, and recording and reproduction are performed using this electromagnetic field. With such a configuration, it is possible to realize high-density recording that has never been seen before.

Further, by forming a minute gap for generating an electromagnetic field in a local region by the irradiation of the laser light of the optical head with a metal member arranged on both sides with a dielectric material thinner than the wavelength of the irradiation laser light interposed therebetween. A desired minute gap can be easily produced.

Further, by disposing a member made of a material different from that of the metal member on the surface of the metal member sandwiching the dielectric material on the side opposite to the surface in contact with the dielectric, the minute gap comes into contact with the recording medium and is damaged. Can be prevented.

Further, a transparent member having a curved surface on which the laser light is incident is integrated with the surface on which the laser light of the laser light of the optical head having a minute gap is incident,
The focused spot of the laser beam focused on the region of the minute gap can be made smaller, and the energy of the laser beam can be effectively used to perform stable recording.

Further, by recording information on the recording layer of the recording medium by an electromagnetic field generated in a local area near the minute gap of the optical head, it is possible to stably record information on the recording medium at high density. it can.

Further, in order to detect the light transmitted through the recording medium with a photodetector to reproduce the information recorded in the recording medium or to scan the optical head with the light propagating from the recording medium into the optical head. By detecting with a photodetector attached to the arm or the optical head, it is possible to stably reproduce the information recorded at high density on the recording medium with a simple configuration.

Further, a photodetector for detecting the light propagating inside the optical head is provided at a position where it does not intersect with the surface of the principal ray of the laser light with which the optical head is incident, and only the reproduced information is reproduced. The S / N of information reproduction can be improved by making the contained light enter the photodetector.

Furthermore, the wiring for guiding the electric signal from the photodetector mounted on the optical head to the signal processing circuit provided at a place other than the optical head is integrated with the suspension, so that the movement of the suspension is impaired. It is possible to prevent information from being recorded and to stably record and reproduce information on and from the recording medium.

Further, an antireflection film is formed on a portion where the light from the recording medium propagates, passes through the slider of the optical head, and is emitted, so that the light containing the information of the recording medium is efficiently incident on the photodetector. Therefore, good reproduction of recorded information can be realized.

[Brief description of drawings]

FIG. 1 is a block diagram of an information recording / reproducing apparatus of the present invention.

FIG. 2 is a side view showing a minute gap of the optical head.

FIG. 3 is a perspective view showing a configuration of an optical head.

FIG. 4 is a schematic diagram showing an electromagnetic field generated in a minute gap of an optical head.

FIG. 5 is a configuration diagram of a second information recording / reproducing apparatus.

FIG. 6 is a side view showing a minute gap formed by various grooves.

FIG. 7 is a perspective view of an optical head in which a minute gap is formed by metal members sandwiching a dielectric.

FIG. 8 is a side view showing a minute gap formed by metal members sandwiching a dielectric.

FIG. 9 is a schematic diagram showing a state in which an optical head is in contact with a recording medium.

FIG. 10 is a block diagram of a third information recording / reproducing apparatus.

FIG. 11 is a perspective view of an optical head provided with a transparent member having a curved surface on which laser light is incident.

FIG. 12 is a configuration diagram of an information recording / reproducing apparatus which reproduces by utilizing reflected light of a recording medium.

FIG. 13 is a schematic diagram showing an arrangement position of a photodetector with respect to an optical head.

FIG. 14 is a configuration diagram of an information recording / reproducing apparatus having an optical head provided with an antireflection film.

FIG. 15 is a configuration diagram of an information recording / reproducing apparatus having an optical head to which a photodetector is attached.

FIG. 16 is a layout diagram of a photodetector attached to an optical head in which a minute gap is formed by metal members sandwiching a dielectric.

FIG. 17 is a configuration diagram showing wiring of a photodetector attached to an optical head.

FIG. 18 is a circuit diagram showing a drive circuit of a light source.

FIG. 19 is a configuration diagram of a conventional example.

[Explanation of Codes] 1; Information recording / reproducing device, 2; Transparent substrate 3, Recording layer, 4;
Recording medium, 5; arm, 6; suspension, 7; optical head, 8; optical system, 9; arm, 10; photodetector, 1
1; slider, 12; metal surface, 12b; minute gap, 1
3; light source, 14; collimating lens, 15; concave reflecting mirror, 16; laser light.

Continued front page    F-term (reference) 5D119 AA11 AA22 AA38 AA43 BB04                       EB02 EC33 EC35 JA34 JA64                       JA65 MA05 MA06                 5D789 AA11 AA22 AA38 AA43 BB04                       CA21 CA22 CA23 EB02 EC33                       EC35 JA34 JA64 JA65 MA05                       MA06

Claims (10)

[Claims] 1. A slider for scanning on a recording medium in an optical pickup which is arranged close to the recording medium, records information on the recording medium by irradiated light, and reproduces the information recorded on the recording medium. Is provided in
An optical head that has a metal surface provided with a minute gap having a width narrower than the wavelength of the laser light, and generates an electromagnetic field in a local region by the laser light irradiated in the vicinity of the minute gap, and a metal surface of the optical head. An optical pickup having an irradiation optical system in which a polarization direction of laser light applied to a minute gap is parallel to a surface of a recording medium and perpendicular to an incident surface. 2. The optical head is formed by a metal member having a minute gap for generating an electromagnetic field in a local region upon irradiation with laser light with a dielectric material thinner than the wavelength of the applied laser light sandwiched therebetween. The optical pickup according to claim 1. 3. The optical pickup according to claim 2, wherein a member made of a material different from that of the metal member is disposed in contact with a surface of the metal member sandwiching the dielectric member, the surface being opposite to the surface in contact with the dielectric member. 4. The optical pickup according to claim 1, wherein a transparent member having a curved surface on which the laser light is incident is integrated with a surface on which the laser light is incident on the optical head having the minute gap. . 5. The optical pickup according to any one of claims 1 to 4, wherein information is recorded on a recording layer of a recording medium by an electromagnetic field generated in a local area near a minute gap of an optical head. An information recording / reproducing apparatus characterized by: 6. The information recorded on the recording medium is reproduced by detecting light transmitted through the recording medium with a photodetector.
Information recording / reproducing apparatus described. 7. The information recorded on the recording medium is detected by detecting light propagating from the recording medium into the optical head by an arm for scanning the optical head or a photodetector mounted on the optical head. The information recording / reproducing apparatus according to claim 5. 8. The photodetector for detecting the light propagating inside the optical head is provided at a position which does not intersect the surface of the principal ray of the laser light with which the optical head is incident. Information recording / reproducing device. 9. The wiring for guiding an electric signal from a photodetector mounted on the optical head to a signal processing circuit provided at a place other than the optical head is integrated with a suspension. Information recording / reproducing device. 10. The information recording / reproducing apparatus according to claim 7, 8 or 9, wherein an antireflection film is formed in a portion where light from the recording medium propagates, passes through a slider of an optical head, and exits.