JP2000163793A - Optical head, disk device, and manufacture of optical head - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical head, a disk device, an optical device, and manufacture of the optical head which permit high-density recording of recording media, and are miniaturized and improved in data transfer rate. SOLUTION: When a laser beam 2a is emitted from a semiconductor laser unit 2, the laser beam 2a is shaped into a parallel beam 2b by a collimator lens 3, and is reflected on a mirror 4 before converged by an object lens 5, and then made incident on a plane of incidence 6a of a transparent medium for condensing. Converged light 2c made incident on the plane of incidence 6a is refracted through the plane of incidence 6a, and the refracted light 2d is condensed on a plane 6b for condensation, and a light spot 9 is formed, and near field light 10 seeps out of a minute hole 7a. The near field light seeping out of the minute hole 7a is made incident to a recording film 8a of a recording medium 8 as propagating light, and this light makes it possible to record and reproduce on/from the recording film 8a.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical head, a disk device, an optical element, and a method of manufacturing an optical head using near-field light, and more particularly, to a method for increasing the recording density of a recording medium, reducing the size and size of the recording medium. The present invention relates to an optical head, a disk device, an optical element, and a method of manufacturing an optical head that improve a data transfer rate.

[0002]

2. Description of the Related Art In an optical disk device, the density of an optical disk has been increased from a compact disk (CD) to a digital video disk (DVD). With the increase in capacity, an increase in capacity is increasingly required.

[0003] The recording density of an optical disk is basically controlled by the diameter of a light spot formed on a recording medium. In recent years, a technique of near-field light of a microscope has been applied to optical recording as a technique for reducing the diameter of a light spot. As a conventional optical disk device using this near-field light, for example, a document (Jpn. J. Appl. Phys., Vol. 35)
(1996) P.A. 443) and US Patent Publication USP5
497359.

FIGS. 21 (a) and 21 (b) show references (Jpn.
Appl. Phys. , Vol. 35 (1996) p.
443) shows an optical disk device. As shown in FIG. 21A, the optical disk device 190 includes a semiconductor laser 191 that emits a laser beam 191a, and a laser beam 191a from the semiconductor laser 191 and a parallel beam 191a.
b, a coupling lens 192 shaped to b
has an optical fiber 193 polished in a tapered shape so as to become thinner from the output end 193a toward the output end 193b, and transmits the parallel beam 191b from the coupling lens 192 to the input end 193a.
And a recording medium 195 recorded by near-field light 191c leaking from the emission end 193b of the optical fiber 193.

[0005] The recording medium 195 is a phase change medium of GeSb.
It has a recording layer 195a made of Te and has a near-field light 191c.
Is heated by the incident light, causing a phase change between crystal and amorphous, and is recorded using the change in reflectance between the two.

The optical fiber 193 has an incident end 193a having a diameter of 10 μm and an emitting end 193b having a diameter of 50 nm, and is coated with a metal film 194b such as aluminum through a cladding 194a. Prevents leaks. Since the diameter of the near-field light 191c is substantially equal to the diameter of the emission end 193b, a high recording density of several tens of Gbits / inch ² is possible.

For reproduction, as shown in FIG. 21B, the recording layer 195a is irradiated with near-field light 191c having a low power that does not cause a phase change by using the same optical head as used for recording. The reflected light 191d therefrom is collected by a condenser lens 196.
The light is focused on a photomultiplier tube (hereinafter abbreviated as “photomultiplier”) 197 and detected.

[0008] FIG.
59 shows an optical head of an optical disk device described in No. 59. The optical head 50 includes an objective lens 5 that collects the parallel light 51.
2 and a bottomed spherical SIL arranged such that the bottom surface 54a is orthogonal to the convergent light 53 from the objective lens 52.
(Solid Immersion Lens) 54. Parallel light 51
Is converged by the objective lens 52, and the convergent light 53 is incident on the spherical incident surface 54b.
A light spot 55 is formed on the substrate. Inside the SIL 54,
Since the wavelength of light becomes shorter in inverse proportion to the refractive index of the SIL 54, the light spot 55 also becomes smaller in proportion thereto. Most of the light condensed on the light spot 55 is totally reflected toward the incident surface 54b, but part of the light leaks out of the light spot 55 to the outside of the SIL 54 as near-field light 57. The SIL 54 is located at a distance sufficiently smaller than the wavelength of light from the bottom surface 54a.
When the recording medium 56 having the same refractive index as that of
The near-field light 57 couples with the recording medium 56 and the recording medium 5
6 becomes the propagating light. Information is recorded on the recording medium 56 by the propagated light.

The SIL 54 is configured such that the parallel light 51 is focused at a position r / n (r is the radius of the SIL) from the center 54c of the hemispherical surface 54b (this is referred to as Super).
Called the SIL structure. ), The spherical aberration due to the SIL 54 is small, the numerical aperture inside the SIL 54 can be increased, and the light spot 55 can be further miniaturized. That is, the light spot 55 is miniaturized as in the following equation (1). D _1/2 = kλ / (n · NA _i ) = kλ / (n ² · NAo) (1) where D _1/2 : spot diameter where the light intensity is k: light beam Is a proportional constant (usually 0.
Λ: wavelength of light beam n: refractive index of SIL 54 NAi: numerical aperture inside SIL 54 NAo: numerical aperture of light incident on SIL 54 light spot 5 without parallel light 51 being absorbed on the optical path
Since the light is condensed as 5, a high light use efficiency is obtained.
As a result, a light source having a relatively low output can be used, and the reflected light can be detected without using a photomultiplier.

[0010]

However, according to the conventional optical disk device 190, a minute light spot of about several tens of nm can be formed on the recording medium. However, since the optical fiber 193 is tapered, the optical fiber 193 is formed. A part of the laser incident on the surface is absorbed inside, and the light utilization efficiency is 1/1000.
There is a problem that it becomes lower as follows. Therefore, the reflected light 1
I have to use Photomaru 197 to detect 91d,
The optical head is large and expensive. In addition, Photomaru 19
7 has a slow response speed and a heavy optical head, so that high-speed tracking cannot be performed. Therefore, since the optical disk cannot be rotated at a high speed, there are many problems such as a low transfer rate, and many improvements are required for practical use.

FIG. 23 shows a conventional optical head 5 shown in FIG.
0 to explain the problem.
Pacific Data Storage Conf
#OC of erence (Taiwan, '97 .7.)
-1 and shows the relationship between the refractive index n of the SIL 54 and NAo. N of light incident on SIL 54
A, that is, the maximum value θmax of the incident angle θ and the refractive index n of the SIL 54 have a reciprocal relationship, and both cannot be increased independently. As can be seen from the figure, as the refractive index n of the SIL 54 increases, the maximum value NAomax of the incident light NAo gradually decreases. This is the maximum value N
This is because when the NAo increases more than Aomax and the incident angle further increases, the light directly enters the recording medium 56 without passing through the SIL 54, so that the light spot 55 at the position of the recording medium 56 spreads. For example, when the refractive index n = 2, NAomax is 0.44, and the product n · NAomax of both is 0.8 to 0.9 in any combination of both. This is a theoretical limit, and actually becomes a smaller value (0.7 to 0.8).

Regarding the light collection experiment using the Super SIL, see B.S. D. Terris et al., Appl. Phys
s. Lett. , Vol. 68, ('96), p. 14
1. In the report. According to this report, a SuperSIL having a refractive index n = 1.83 is placed between an objective lens and a recording medium, and a laser beam having a wavelength of 0.83 μm is condensed to obtain a light spot diameter of 0.317 μm.
That is, light collection equivalent to D _1/2 = λ / 2.3 is achieved. In this case, NA is 0.4 and n · NAmax is 0.2.
It is about 73. Also, the possibility of a recording density of 0.38 × Gbits / cm ² , which is several times the conventional value, is verified using this system.

That is, according to the conventional optical head 50,
Although the light use efficiency is high, the refractive index n of SIL and the maximum NAom
ax has a reciprocal relationship, so the product n · NAoma of both
The theoretical limit for x is 0.8-0.9, and in practice 0.7
０．８0.8, and even when a laser beam having a wavelength of 400 nm is used, the light spot can be narrowed down to only about 0.2 μm in diameter at most. However, there is a problem that the recording density cannot be increased.

FIG. 24 shows an optical head disclosed in the document “Nikkei Electronics (1998.6.15) (No. 718)”. This optical head is a SIM (Solid)
It is referred to as an immersion mirror type, and has a concave spherical incident surface 101a on which the parallel laser beam 2b is incident, a light collecting surface 101b provided at a position facing the light incident surface 101a, and a periphery of the light collecting surface 101b. Plane reflecting surface 101c provided on the
a, a transparent condensing medium 101 having an aspherical reflecting surface 101d formed around the surface a, a planar reflecting film 102 formed on the surface of the planar reflecting surface 101c, and an aspherical reflecting surface 1
01d. In the optical head thus configured, the parallel laser beam 2b is incident on the incident surface 101 of the transparent condensing medium 101.
a, the parallel laser beam 2b incident on the incident surface 101a is diffused on the incident surface 101a, and the diffused light 2d is reflected on the planar reflecting film 102, and the reflected light 2e
Is further reflected by the aspherical reflective film 103 and
The light is condensed on 1b, and a light spot 9 is formed on the condensing surface 101b. The near-field light 10 oozing from the light-collecting surface 101b enables recording and reading on the recording layer 8a of the recording medium 8. The planar reflecting surface 1 of the transparent light-collecting medium 101
01c has a numerical aperture NA of about 0.8, and the transparent condensing medium 1
01 has a refractive index of 1.83.
An internal NA of about 1.5 is possible.

According to this optical head, the actually obtained spot diameter is as large as 0.35 to 0.39 μm, and there is a limit to miniaturization of the spot diameter formed on the light collecting surface of the transparent light collecting medium. Therefore, there is a problem that a high recording density cannot be achieved.

Accordingly, it is an object of the present invention to provide an optical head, a disk device, an optical element, and a method for manufacturing an optical head, which can achieve a high recording density of a recording medium, achieve a reduction in size and improve a data transfer rate. Is to do.

[0017]

In order to achieve the above object, the present invention provides a laser light emitting means for emitting laser light,
An optical system that includes a transparent light-collecting medium, and forms an optical spot by condensing the laser light from the laser light emitting means on a light-collecting surface of the transparent light-collecting medium; An optical head, comprising: a light blocking member provided at an upper position and having a small hole having an area smaller than the light spot at a position where the light spot is formed. In order to achieve the above object, the present invention provides a rotating optical disc,
In a disk device that irradiates near-field light on the optical disk and detects information recorded on the optical disk,
A disk device comprising: the optical head according to any one of claims 1 to 54; and a driving unit that drives the optical head. In order to achieve the above object, the present invention provides a transparent light-collecting medium having a light-collecting surface on which a light spot is formed by incident laser light, and the transparent light-collecting medium has an outer diameter smaller than the light spot. A photoresist having a diameter is formed, a concave portion is formed by removing an area of the transparent light-condensing medium where the photoresist does not exist by etching at a predetermined depth equal to or less than the wavelength of the laser light, and a light shielding material is formed in the concave portion. A method of manufacturing an optical head, comprising forming a light shielding body having an opening with a small outer diameter by depositing the light shielding body. The invention provides an optical head manufacturing method for manufacturing an optical head according to any one of claims 1 to 54, wherein the transparent light-collecting member is formed during the step of forming the light-shielding member. A method of manufacturing an optical head, comprising a step of performing an etching step from the light-collecting surface side of an optical medium.

[0018]

FIG. 1 shows a main part of an optical head 1 according to a first embodiment of the present invention. This optical head 1
Is a semiconductor laser 2 that emits a laser beam 2a, and a laser beam 2a from the semiconductor laser 2 is converted into a parallel beam 2b.
Collimator lens 3 and collimator lens 3
4 that reflects the parallel beam 2b from the mirror in the vertical direction
An objective lens 5 for converging the parallel beam 2b reflected by the mirror 4, a transparent condensing medium 6 on which the light 2c converged by the objective lens 5 enters and forms a light spot 9 on a condensing surface 6b; And a light-shielding film 7 having fine holes 7a formed on the surface of the light-collecting surface 6b of the transparent light-collecting medium 6.

The semiconductor laser 2 is a red laser (630 nm) having the shortest wavelength on the market or an AlGalnN laser currently under development.
Blue laser (410 nm) can be used.
By using a blue laser (410 nm), the light spot diameter can be reduced to 0.15 μm or less, and the proportion of light entering the opening can be increased.

FIG. 2A shows the transparent light-collecting medium 6 and the light-shielding film 7, and FIG. 2B is a bottom view thereof.

The transparent light-collecting medium 6 is made of a crystalline material such as heavy flint glass (refractive index = 1.91), cadmium sulfide CdS (refractive index 2.5), zinc blende ZnS (refractive index 2.37). There is no upper limit if the refractive index is greater than 1, and a material having a higher refractive index can be used. In this embodiment, heavy flint glass having a refractive index of 1.91 is used. By using a crystalline material,
The light spot diameter can be reduced by 20% or more compared to heavy flint glass. Further, as shown in FIG. 2 (a), the transparent condensing medium 6 refracts convergent light 2c from the objective lens 5 incident on the spherical incident surface 6a at the incident surface 6a, and converts the refracted light 2d. It has a spherical shape (Super SIL structure) so that the light spot 9 is formed by condensing the light on the condensing surface 6b on the bottom surface. Here, that the light spot 9 is formed on the light converging surface 6b means that the light converging surface 6b is located within the depth of focus of the light spot.

The light shielding film 7 is made of titanium (T) as a light shielding material.
i) having a thickness (for example, 10 nm) smaller than the wavelength of the laser light, and a diameter sufficiently smaller than the light spot 9 at a position corresponding to the light spot 9 and a diameter (for example, 50 nm) smaller than the wavelength of the laser light. Are formed to block light emitted directly from the light spot 9 to the outside, and to form near-field light 10 having substantially the same diameter as the small holes 7a. Although the micro holes 7a are circular in the present embodiment, other shapes such as a rectangular shape may be used. By using a rectangular shape, the track pitch can be made smaller than that of a circular shape, and high recording density can be achieved. Further, the diameter of the minute holes 7a may be smaller than 50 nm in accordance with the progress of the technology for increasing the recording density of the optical disk and the minute hole forming technology.

The spot diameter of the light spot 9 is set to r / n (r and n are the radius and the refractive index of the transparent light-condensing medium 6) from the center 6c of the spherical surface, respectively, as described in the conventional example. Thus, it is expressed by the following equation (1). D _1/2 = kλ / (n · NAi) = kλ / (n ² · NAo) (1) where, NAi: numerical aperture inside transparent light-collecting medium 6 NAo: transparent light-collecting medium 6 Numerical aperture of the incident light The light spot 9 is miniaturized in inverse proportion to the refractive index n of the transparent light-condensing medium 6 as shown in the equation (1), and condensing with small spherical aberration becomes possible. However, the possible angle of incidence θ of the convergent light 2c, that is, the numerical aperture NAo and the refractive index n have a reciprocal relationship, and both cannot be increased independently. The product of the refractive index n and the maximum value of the NA is about 0.88, and is actually about 0.8 or less in consideration of the beam eclipse. Accordingly, the minimum light spot diameter D _1/2 min is given by the following equation (2). D _1/2 min = kλ / (0.8n) ≒ 0.6λ / n (when k = 0.5) (2) Accordingly, as the transparent light-collecting medium 6, the largest refractive index as an amorphous material is obtained. Heavy flint glass (refractive index = 1.9)
1) and a red laser (wavelength 630)
nm), the minimum light spot diameter D _1/2 min
Is 0.20 μm. Blue laser (400n
m) in the case of using the minimum spot diameter D _1/2 min is about 0.13 [mu] m. Moreover, those light spots 9
It has an almost Gaussian intensity spread distribution.

Since the diameter of the minute hole 7a is smaller than the laser wavelength, no propagating light is emitted from the minute hole 7a, and the near-field light 10 spreads to a close distance approximately equal to the diameter of the minute hole 7a. Is out. By arranging a dielectric material, specifically, the recording medium 8 close to the near-field light 10, the near-field light 10 enters the recording layer 8 a of the recording medium 8 as propagating light, and the light is used for recording. Recording and reading on the layer 8a become possible. The amount of the propagated light is approximated by the following equation (3).

(Equation 1) Here, Io: the total power of the laser ω: the radius of the light spot 9 on the light-collecting surface 6b a: the radius of the minute hole 7a That is, in the case of a red laser, the light amount of the laser beam passing through the minute hole 7a is the light spot 9 This is about 15% of the total power and 20% or more in the case of blue light, so that the light-collecting efficiency can be improved to 100 times or more in the case of using a conventional optical fiber.

FIGS. 3A to 3D show one embodiment relating to the method of attaching the light-shielding film 7 and the method of forming the minute holes 7a. First, a photoresist film 70 for electron beam exposure is applied to the bottom surface 6d of the transparent converging medium 6 having a spherical shape.
(FIG. 3 (a)), and the bottom surface 6d is subjected to dry etching by about 100.degree. By dry etching so as to leave a portion 70a corresponding to the pattern and a protective portion 70b corresponding to the periphery of the light-shielding film 7. Etch anisotropically and use convex 6f
Then, an attachment surface 6g of the light shielding film is formed (FIG. 3B). A CF ₄ gas is used as an etching gas. Next, a Ti film 71 for a light-shielding film is deposited on the entire surface by sputtering at about 100 ° (FIG. 3 (c)), and then the photoresist film 70 (70a, 70b) is dissolved to form a portion 70a of the minute hole 7a. And a portion 70 for protecting the light shielding film 7
The Ti film 71 of b is lifted off (FIG. 3D). Thus, the light-shielding film 7 having the fine holes 7a is formed. The light-shielding film 7 may be a film other than the Ti film as long as it has a light-shielding property and an excellent adhesion to glass.
When the minute holes 7a filled with the convex portions 6f of the transparent light-collecting medium are formed therein as in the method of the present embodiment, the minute holes are simply formed in the light-shielding film 7 and the inside becomes an air layer. On the other hand, since the air gap between the convex portion 6f and the recording medium becomes small, the propagation efficiency of near-field light is improved. Light shielding film 7
In contrast, the tip of the convex portion 6f may protrude,
As shown in FIG. 3, when the light-shielding film 7 and the convex portion 6f of the transparent light-condensing medium positioned in the minute hole 7a are formed to be flat when viewed from the near-field light emission side, the proximity Since the spread of the field light can be suppressed, it is more suitable for high-density recording.
By the way, when the convex portion 6f is provided on the transparent light-collecting medium as in the present embodiment, the tip of the convex portion corresponds to the light-collecting surface 6b. Means that the tip of the projection 6f is located within the depth of focus. When the thickness of the light-shielding film is sufficiently small as in the present embodiment, both the tip of the projection and the surface 6g of the light-shielding film are often located within the focal depth of the light spot.
It does not really matter whether the spot forming position is at the tip of the projection or at the attachment surface 6g. Further, when an etching step is included in the step of forming the minute holes 7a,
When etching is performed from the side of the light-collecting surface 6b of the transparent light-collecting medium, the side surface of the convex portion 6f is usually exposed to the etching gas. When an appropriate inclination is formed (not shown), when the light-shielding film 7 is formed around this, the light-shielding film has a tapered shape in which the hole narrows in the direction of propagation of the near-field light in the minute hole 7a. The light condensing effect of the field light can be enhanced.

Next, the operation of the optical head 1 according to the first embodiment will be described. When a laser beam 2a is emitted from the semiconductor laser 2, the laser beam 2a is shaped into a parallel beam 2b by a collimator lens 3, and
Then, the light is converged by the objective lens 5 and is incident on the incident surface 6a of the transparent light-collecting medium 6. The convergent light 2c incident on the incident surface 6a is refracted on the incident surface 6a, and the refracted light 2d is condensed on the converging surface 6b, and the light spot 9c is converged on the converging surface 6b.
Are formed, and the near-field light 10 oozes out from the minute holes 7a.
The near-field light 10 oozing out of the minute holes 7a is
Of the recording layer 8a as propagating light, and this light enables recording and reproduction on the recording layer 8a.

According to the optical head 1 of the first embodiment, the near-field light oozing out of the light spot 9 formed on the light-collecting surface 6b is narrowed by the minute holes 7a of the light-shielding film 7. The near-field light spot formed on the recording medium 8 can be miniaturized. Further, even if the near-field light is narrowed down by the minute hole 7a having a diameter smaller than the wavelength of the laser beam 2a, the central light intensity of the near-field light from the minute hole 7a does not decrease so much, and high light use efficiency can be obtained. Therefore, the semiconductor laser 2 having a relatively low output of several milliwatts can be used as a light source. Further, the reflected light from the recording medium 8 also increases in proportion to the propagating light from the minute holes 7a, so that a Si photodetector conventionally used in conventional optical disk memories can be used for detecting the reproduction light, and a photomultiplier can be used. The optical head 1 can be reduced in size and weight, and high-speed reading can be performed.

FIGS. 4A and 4B show modified examples of the light shielding film 7. FIG. As shown in FIG. 4 (a), the light-shielding film 7 tilts the surface to be etched with respect to the incident light by an operation such as tilting the bottom surface 6d when etching the bottom surface 6d of the transparent light-condensing medium 6, thereby forming a convex shape. Alternatively, the shape may be a concave conical surface. Also,
As shown in FIG. 4 (b), when etching the bottom surface 6d of the transparent light-condensing medium 6, fine irregularities may be formed on the etched surface by an operation such as etching at a relatively large current and at a high speed. If the reflectance of the surface 7b of the light shielding film 7 is high, the light shielding film 7
The intensity of the light reflected by the light source becomes stronger than the signal light returning from the minute hole 7a, and the amplification factor of the pre-amplification at the time of signal processing cannot be increased, so that the S / N is reduced. On the other hand, if the absorptance in the light-shielding film 7 is high, the temperature of the portion of the light-shielding film 7 irradiated with the light spot 9 rises, and this heat undesirably affects recording. Therefore, by adopting the structure shown in FIGS. 4A and 4B, the amount of the reflected light 2e returning to the objective lens 5 is reduced, and the S / N can be improved. On the other hand, the reflected light passing through the minute hole 7a is incident light 2c, 2d
Follow the same path as above and enter a photodetector (not shown). As a result, the ratio of stray light entering the photodetector can be reduced, so that the gain of the DC preamplifier can be increased and the S / N can be improved.

FIG. 5 shows a main part of an optical head according to a second embodiment of the present invention. The optical head 1 has a transparent condensing medium 6 formed in a hemispherical shape (SIL type), and the other configuration is the same as that of the first embodiment. The convergent light 2c incident on the incident surface 6a of the transparent light-collecting medium 6 is condensed at the center of the spherical surface. In this case, since the convergent light 2c is not refracted on the incident surface 6a, the numerical aperture N
A is the same as the NA of the objective lens 5 at the time of emission, and the NA cannot be increased by refraction. Accordingly, the light spot diameter in this case is as shown in the following equation (4). D _1/2 = kλ / (n · NAo) (4) where, NAo: the numerical aperture of light incident on the SIL-type transparent light-collecting medium 6.

According to the optical head 1 according to the second embodiment, as in the first embodiment, the diameter of the near-field light 10 is determined by the diameter of the minute hole 7a, and is equal to the diameter of the light spot 9. Since it does not depend on the optical head, the influence of aberration and displacement is small, so that NAo can be set to 0.8, which is relatively large as compared with the optical head using the conventional SIL.
Light collection equivalent to that of the r SIL structure is possible. That is,
Red laser (wavelength 630nm) and blue laser (400n
When m) is used, the minimum light spot diameters of 0.2 μm and 0.13 μm are obtained, respectively, and the light amount of the near-field light 10 oozing out of the minute holes 7a, that is, the light use efficiency is almost the same as in the first embodiment. Can be.

FIG. 6A shows a main part of an optical head according to a third embodiment of the present invention, and FIG. 6B shows a bottom view thereof. The optical head 1 includes a semiconductor laser 2 for emitting a laser beam 2a, and a collimator lens 3 for shaping the laser beam 2a from the semiconductor laser 2 into a parallel beam 2b.
And a transparent light-condensing medium 6 for converging the parallel beam 2b from the collimator lens 3 to form a light spot 9 on the light-condensing surface 6b, and adhered to the surface of the reflection surface 6e of the transparent light-condensing medium 6 Reflecting film 11 and light-collecting surface 6b of transparent light-collecting medium 6
And a light-shielding film 7 having fine holes 7a adhered and formed on the surface of the substrate.

The transparent light-condensing medium 6 is made of, for example, heavy flint glass (refractive index: 1.91) and has an incident surface 6a on which the parallel beam 2b is incident and a reflection reflecting the parallel beam 2b incident on the incident surface 6a. It has a surface 6e and a light-collecting surface 6b on which the light spot 9 is formed. The reflection surface 6e uses a part of the paraboloid of revolution. The principal axis of the section (6e) of the paraboloid of revolution is taken on the x-axis, the vertical axis is taken on the y-axis, and the focal position is (p,
0), the cross section (6e) is represented by the following equation (5). y ² = 4 px (5) In addition, when light is condensed inside the transparent light-condensing medium 6 using a paraboloid of revolution, it is possible in principle to collect light with no aberration (optical: Hiroshi Kubota, Iwanami Bookstore, p. 283), so that the light spot 9 can be collected by a single light-collecting reflector.
Further, in this method, there is no limitation on the refractive index of the transparent light-collecting medium 6 and the numerical aperture NA of the condensed light by the reflection surface 6e. Even when the refractive index is high, NA can take a value close to 1. Therefore, the light spot diameter in this case is given by the following equation (6). D _1/2 = kλ / (n · NAr) (6) where, NAr: p of the focal position of the numerical aperture paraboloid of revolution of the reflected light of the reflecting surface 6 e is p = 0.125 mm, and If the upper end of the surface is (x, y) = (2 mm, 1 mm),
The convergence angle from the upper end is 60 degrees or more, and the NA of the reflection surface 6e is 0.98, which is 1.6 times or more as large as NA = 0.6 in the conventional DVD.

According to the optical head 1 according to the third embodiment, NAr is set to 0.
About 9 is the limit, but red laser (wavelength 630nm)
When a blue laser (400 nm) is used, the light spot diameter can be reduced to 0.19 μm and 0.12 μm, respectively. About 20 compared to the form
% Can be increased. In addition, chromatic aberration does not occur due to reflection type light collection. The optical system according to the present embodiment is a so-called infinite system, that is, a laser beam 2b between the collimator lens 3 and the incident surface 6a of the transparent condensing medium 6.
Are parallel to each other, so that the focal position shift with respect to the temperature fluctuation is small.

FIG. 7 shows a main part of an optical head according to a fourth embodiment of the present invention. The optical head 1 uses a transparent condensing medium 6 having a planar reflecting surface 6e,
In this example, a reflective hologram is used as the reflective film 11 on the surface of e, and the other components are configured in the same manner as in the third embodiment. The reflection hologram may be an uneven binary hologram or a volume hologram made of an organic photosensitive material. Further, a reflective film made of a highly reflective metal layer such as aluminum may be provided outside these holograms. By making the reflection surface 6e of the transparent light-collecting medium 6 flat, productivity can be improved as compared with the third embodiment.

FIGS. 8A and 8B show a main part of an optical head according to a fifth embodiment of the present invention. This optical head 1
As shown in FIG. 3A, the transparent light-collecting medium 6 has a SIM
A semiconductor laser 2 that emits a laser beam 2a, a collimator lens 3 that shapes the laser beam 2a from the semiconductor laser 2 into a parallel beam 2b, and a so-called (Solid Image Mirror) type is used. A mirror 4 for reflecting the parallel beam 2b from the collimator lens 3 in the vertical direction, a concave spherical incident surface 6a on which the parallel beam 2b from the mirror 4 is incident, and a condensing surface provided at a position facing the incident surface 6a 6b, and an aspherical reflecting surface 6e formed around the incident surface 6a
, A reflection film 11 formed on the surface of the reflection surface 6e of the transparent light collection medium 6, and a non-adhesion film formed on the surface of the light collection surface 6b of the transparent light collection medium 6. And the micro holes 7
a) and a light-shielding film 7 having a. The micro holes 7a are
As shown in FIG. 3B, the light spot 9 is formed at a position corresponding to the light spot 9 as in the first embodiment.

Next, an optical head 1 according to a fifth embodiment will be described.
Will be described. Laser beam 2 from semiconductor laser 2
When the laser beam 2a is emitted, the laser beam 2a is shaped by the collimator lens 3, is reflected by the mirror 4, and then enters the incident surface 6a of the transparent light-collecting medium 6. The parallel beam 2b incident on the incident surface 6a is diffused on the incident surface 6a, and the diffused light 2d is reflected on the light shielding film 7 and the reflected light 2e
Is reflected by the reflection film 11 and condensed on the light-collecting surface 6b, a light spot 9 is formed on the light-collecting surface 6b, and the near-field light 10 oozes out from the minute hole 7a. The near-field light 10 oozing out of the minute holes 7a enters the recording layer 8a of the recording medium 8, and this light enables recording and reading on the recording layer 8a.

According to the optical head 1 of the fifth embodiment, similarly to the first embodiment, the recording density in the track direction X can be increased, and in the first embodiment, Since the objective lens used is unnecessary, the configuration can be simplified. Further, even if the transparent light condensing medium 6 expands or contracts, the light condensing point does not change, so that it can cope with a temperature change. The light-shielding film 7 may have the structure shown in FIGS. 4 (a) and 4 (b). Note that the diameter of the light spot is about 0.2 μm or less as described above. It is necessary to adjust with the following error. In the light condensing using the SIL as described in the first and second embodiments, light is condensed using an objective lens and the converged light is incident on the SIL. Since the position of the light spot varies depending on the position, the positions of the three must be adjusted with high accuracy. On the other hand, in the optical heads shown in the third to fifth embodiments, the parallel light beam is directly incident on the transparent light-collecting medium of the present example without using the objective lens for light collection, Even if the relative position between the parallel light beam and the transparent light-collecting medium is shifted, the position of the light spot can be kept from changing. Therefore, the positioning accuracy of each can be greatly relaxed, which is very advantageous in manufacturing.

FIG. 9A shows an optical disk apparatus according to the first embodiment of the present invention, and FIG.
It is -A sectional drawing. In the optical disc device 100, a recording layer 121 made of a phase-change material of GeSbTe is formed on one surface of a disc-shaped plastic plate 120, and the optical disc 12 is rotated via a rotation shaft 30 by a motor (not shown). An optical head 1 for performing optical recording / optical reproduction on the recording layer 121, a linear motor 32 for moving the optical head 1 in a tracking direction 31, and a suspension 3 for supporting the optical head 1 from the linear motor 32 side
3, an optical head driving system 34 for driving the optical head 1, and a signal processing system 35 for processing signals obtained from the optical head 1 and controlling the optical head driving system 34.

The linear motor 32 has a tracking direction 3
1 and a movable coil 32b that moves on the pair of fixed portions 32a.
The optical head 1 is supported by the suspension 33 from the movable coil 32b.

FIG. 10 shows the details of the optical disk 12.
The optical disc 12 has a high recording density in response to miniaturization of the near-field light 10 formed by the optical head 1. As the plastic plate 120, for example, a polycarbonate substrate or the like is used, and a groove portion 12a is formed on one surface thereof. The optical disc 12 has an Al reflecting film layer (100 nm thick) 121a and a SiO ₂
Layer (100 nm thick) 121b, GeSbTe recording layer (1
5 nm thick) 121c, SiN layer (50nm thick) 121d
Are laminated to form the recording layer 121. In the present embodiment, information is recorded on the land 12b, the track pitch is 0.07 μm, and the depth of the groove 12a is about 0.06 μm. Mark length is 0.05μ
m, the recording density is 130 Gbits / inch ² ,
For a 12 cm disc, this corresponds to a recording capacity of 210 GB.
The recording density can be increased to 45 times that of the conventional DVD. As an optical recording medium, a read-only disk having uneven pits, a recording / reproducing medium using a magneto-optical recording material or a phase change material, and a write-once type in which uneven pits are formed by light absorption of a dye or the like for recording. Various recording media such as media can be used.

FIG. 11 shows an optical head 1 according to a sixth embodiment of the present invention, wherein FIG. 11 (a) is a side view thereof, and FIG.
Is a bottom view thereof. The optical head 1 has a flying slider 36 that floats on the optical disk 12, and is made of, for example, AlGalnP and has a wavelength of 63
An edge emitting semiconductor laser 2 for emitting a laser beam 2a of 0 nm, a collimator lens 3 for shaping a laser beam 2a emitted from the semiconductor laser 2 into a parallel beam 2b, and a fused quartz plate mounted on a flying slider 36 37A, a holder 37B made of a fused silica plate for fixing the semiconductor laser 2 and the collimator lens 3 on the seat 37A, and a parallel beam 2 from the semiconductor laser 2.
b, a polarizing beam splitter 13 for separating the reflected light from the optical disk 12, a quarter-wave plate 38 for converting the linearly polarized light of the parallel beam 2b from the semiconductor laser 2 into circularly polarized light, and reflecting the parallel beam 2b in the vertical direction. Mirror 4 and an objective lens 5 for converging the parallel beam 2b reflected by the mirror 4
And an upper transparent condensing medium 6 ', and a photodetector 15 attached to the seat plate 37A and inputting reflected light from the optical disc 12 via the beam splitter 13. Further, the whole is housed in a head case 39, and the head case 39 is fixed to a tip of the suspension 33.

The upper transparent condensing medium 6 'is made of, for example, heavy flint glass having a refractive index n = 1.91, has a diameter of 1 mm, and a height of about 1.3 mm. The flying slider 36 is composed of a transparent medium 36 having a refractive index substantially equal to that of the upper transparent light-collecting medium 6 ′, and has a light focusing surface 36 a of the flying slider 36. A spot 9 is formed. That is, the upper transparent light-collecting medium 6 'and the flying slider 36
And constitute an integral transparent light-collecting medium. Flying slider 36
The light-shielding film 7 having the minute holes 7a is formed on the light-collecting surface 36a in the same manner as shown in FIG.

As shown in FIG. 11 (b), the flying slider 36 has a groove 36b so as to generate a negative pressure in a portion other than the periphery of the light spot 9 formed on the light condensing surface 36a. The floating slider 36 and the optical disk 1
2 is kept constant as the flying height. In the present embodiment, the flying height is about 0.06 μm. The lower surface 36c serves as a sliding surface. In addition, the flying height of the flying slider 36 is extremely small, and it is necessary to accurately set the distance between the tip of the convex portion whose tip is the light-collecting surface and the optical disk. As shown here, the tip of the convex portion 6f and the flying slider 36
By controlling the flying height of the flying slider 36, the distance between the tip of the convex portion 6f and the optical disk 12 can be precisely adjusted by setting the lower surface 36c of the optical disk 12 on the same plane. It does not collide with 12 and does not wear.

The optical head drive system 34 modulates the output light of the semiconductor laser 2 with a recording signal at the time of recording, thereby causing a phase change between crystal and amorphous in the recording layer 121, and as a difference in reflectance between the phases. At the time of recording and reproduction, the output light of the semiconductor laser 2 is continuously irradiated without being modulated, and the difference in reflectance at the recording layer 121 is detected by the photodetector 15 as a change in reflected light. Has become.

The signal processing system 35 generates an error signal and a data signal for tracking control based on the reflected light from the optical disk 12 detected by the photodetector 15, and converts the error signal into a high frequency band by a high-pass filter and a low-pass filter. An error signal and an error signal in a low frequency range are formed, and tracking control is performed on the optical head drive system 34 based on these error signals. Here, the tracking error signal is generated by a sample servo method (optical disk technology, Radio Technology Co., p. 95), and this sample servo method uses a staggered mark (Wobble mark).
bleed Track) is intermittently provided on the track,
In this method, an error signal is generated from the fluctuation of the reflection intensity. In the case of the sample servo method, since the recording signal and the tracking error signal are separated in a time-division manner, the two are separated by a gate circuit in a reproducing circuit.
When the sample servo method is used, the photodetector having one light-receiving surface is used, which is suitable for combination with the SCOOP method. The groove 1
The error signal may be generated by a push-pull method using interference with the reflected light from 2a.

Next, the operation of the optical disk device 100 according to the sixth embodiment will be described. The optical disk 12
The flying slider 36 is rotated at a predetermined rotation speed by a motor (not shown), and floats on the optical disk 12 by the action of the negative pressure generated by the rotation of the optical disk 12 and the spring force of the suspension 33. Optical head drive system 3
5 emits a laser beam 2a from the semiconductor laser 2, the laser beam 2a from the semiconductor laser 2 is shaped into a parallel beam 2b by the collimator lens 3, and then the polarization beam splitters 13 and 1/4.
The light passes through the wave plate 38 and enters the incident surface 6'a of the upper transparent light-collecting medium 6 '. The parallel beam 2b is a １ ／ wavelength plate 38
, The light is changed from linearly polarized light to circularly polarized light by the 波長 wavelength plate 38. The circularly polarized parallel beam 2b is converged on the objective lens 5, is refracted and condensed on the incident surface 6'a of the upper transparent condensing medium 6 ', and is condensed on the converging surface 3 of the flying slider 36.
Focus on 6a. A minute light spot 9 is formed on the light-collecting surface 36a of the flying slider 36. A part of the light of the light spot 9 is transmitted from the minute hole 7a under the light spot 9 to the near-field light 10.
Leaks out of the lower surface 36c of the flying slider 36, and the near-field light 10
To perform optical recording or optical reproduction. The light reflected by the optical disk 12 reverses the path of the incident light, is refracted by the incident surface 6'a of the upper transparent light-collecting medium 6 ', is reflected by the mirror 4, and is incident by the quarter-wave plate 38. Light (2a)
After being shaped into linearly polarized light with a polarization plane that differs by 90 degrees,
The light is reflected by the polarization beam splitter 13 in the direction of 90 degrees and enters the photodetector 15. The signal processing system 35 includes the photodetector 1
An error signal and a data signal for tracking control are generated based on the reflected light from the optical disk 12 incident on the optical disk 5, and tracking control is performed on the optical head drive system 34 based on the error signal. The size of the optical head 1 is about 8
mm, width of about 4 mm, and height of about 6 mm. Since recording and reproduction can be performed without performing automatic focus control, an automatic focus control mechanism is not required, and the weight of the optical head 1 can be greatly reduced, and downsizing can be achieved. It was planned. The weight of the optical head 1 is about 0.6 g,
The weight of the movable coil 32b of the linear motor 32 is about 2 g in total for the movable part, the tracking frequency band is 50 kHz, and the gain is 60 or more. In addition, since the eccentricity was suppressed to 25 μm, tracking satisfying the required accuracy of 5 nm could be performed under the rotation of 600 rpm. The average transfer rate in this case is 60 Mbps,
Recording and reproduction of UGA level video signals have become possible.

According to the optical disk device 100 of the sixth embodiment, the maximum refraction angle on the incident surface 6'a of the upper transparent light-collecting medium 6 'is 60 degrees, and the NA is 0.86. As a result, a minute light spot 10 having a spot diameter D _{1/2 of} about 0.2 μm is obtained, and about 20% of the light spot 10 has a diameter of 50 μm.
through the micro-hole 7a of the optical disk 12 as the near-field light 10 and has a very high density (180 G
Bits / inch ² ) long-density optical recording / optical reproduction has become possible. Further, since the recording signal and the tracking error signal are separated in a time-division manner by adopting the sample servo method, the photodetector 15 does not need to be a split type, and for example, a 1 mm square PIN photodiode Can be used. Since the photodetector 15 does not need to be a split type, the detection system can be significantly simplified and lightened.

In the above-described embodiment, the sample servo method is used to generate the tracking control error signal. A wobbled track method of detecting in synchronization and generating an error signal may be used. Also, for tracking of a read-only disc, CD
It is also possible to use a three-spot method as performed in the above. That is, a diffraction grating is inserted between the collimator lens 3 and the polarizing beam splitter 13, and
An error signal can be generated by arranging photodetectors for detecting the reflected light of the primary light from the disc on both sides of the main beam detecting element and calculating the difference between the outputs. It is also possible to perform a push-pull control that detects an imbalance between the left and right of the diffracted light from the side of the recording track and generates an error signal. In this case, the diffracted light is incident on a two-division type photodetector, and a differential output error signal is generated. Further, the optical head 1 of the present embodiment can be used as it is for recording and reproducing on a write-once optical disc (disc having uneven bits formed by light absorption of a dye). Further, by mounting a thin-film coil around the position where the light spot 9 is formed on the lower surface 36c of the flying slider 36 and performing magnetic field modulation, magneto-optical recording using a magneto-optical medium becomes possible. However, in the case of reproduction, in order to generate a signal by detecting the rotation of the plane of polarization of light by polarization analysis, the polarization beam splitter 13 is changed to a non-polarization splitter, and an analyzer is arranged in front of the photodetector. There is a need. In this embodiment, an edge emitting laser is used as a laser source, but a surface emitting laser (VCSEL) is used.
Can also be used. In the case of the surface emitting laser, the maximum output in the fundamental mode (TEM00) is about 2 mW, which is 1/10 or less of that of the edge emitting laser. In the present embodiment, the light spot diameter used in the conventional optical disk device is used. Since the light density can be increased by one digit or more, recording is possible even with a surface-emitting type semiconductor laser. In the case of a surface-emitting type semiconductor laser, wavelength fluctuation due to temperature is small, and chromatic aberration correction can be unnecessary.

FIG. 12 shows a main part of an optical head of an optical disk device according to the seventh embodiment. FIG. 2A is a plan view of the transparent light-collecting medium 6, and FIG.
FIG. 3C shows a portion for driving the transparent light-collecting medium 6.
The optical head 1 of the optical disk device includes a flying slider 36 having an accommodation hole 36d for accommodating the transparent light-collecting medium 6 therein. The other components are provided on the flying slider 36 by the holder 42, and the other components are the same as those of the optical disc device 100 according to the first embodiment. The transparent light-collecting medium 6 has a light-collecting surface 6b, and the light-collecting surface 6b is adjusted to a lower surface 36b for adjusting the distance from the optical disk.
The light-collecting surface 6b may protrude or indent from
The flying slider 36 is disposed so as to be substantially flush with the lower surface 36 b of the flying slider 36.

As shown in FIG. 12C, each of the pair of piezoelectric elements 41 includes a plurality of electrode films 411 connected to the electrode terminals 410 and a multilayer PZT thin film formed between the electrode films 411. 412 (thickness: about 20 μm). The piezoelectric element 41 is attached to the holder 42, supports the light-collecting transparent medium 6 by the pair of piezoelectric elements 41, 41, and scans in the direction perpendicular to the light beam, that is, in the tracking direction 40. I do. In addition,
The transparent medium 6 for condensing light may be moved in the optical axis direction using a piezoelectric element whose deformation direction is in the optical axis direction.

According to the optical disk device of the seventh embodiment, since the weight of the transparent light-collecting medium 6 can be reduced to 5 mg or less, the resonance frequency of the system supporting the transparent light-collecting medium 6 is set to 300 kHz. The electrode terminals 410, 4
A displacement of 0.5 μm or more can be obtained with an applied voltage of 5 V between 10 and 10. Further, by the two-stage control by the piezoelectric element 41 and the linear motor 32, a band of 300 kHz can be obtained with a gain of 80 dB, and tracking can be performed with a precision of 5 nm under a high-speed rotation (3600 rpm). As a result, in the present embodiment, the transfer rate is six times that of the optical disc device 100 of the first embodiment, that is, 360M.
bps. Further, when a multi-beam optical head described later is used, the transmission rate is further increased by 8 times, and a transfer rate of about 3 Gbps can be obtained. Also, 1
An average seek speed of less than 10 ms can be achieved on a 2 cm disc. As a result, the access time at 3,600 rpm becomes 20 ms or less.

FIG. 13 shows an optical disk device according to an eighth embodiment of the present invention. In the first embodiment, the linear motor 32 is used for the seek operation. In the third embodiment, the rotary linear motor 43 used for the hard disk is used. The optical head 1 is connected to a rotary linear motor 43 by a suspension 33 rotatably supported by a rotary shaft 33a. With such a configuration, the rotary linear motor 43 can be disposed outside the optical disc 12, so that the optical head 1 can be made thinner and the entire optical disc apparatus 100 can be downsized. In addition, this allows the optical disc 12 to operate at high speed (3
600rpm), 360Mb on average
A data transfer rate of ps or more becomes possible.

FIG. 14 shows an optical disk device according to the ninth embodiment of the present invention. This optical disk device 100
Is an optical head 1 using the transparent light-collecting medium 6 shown in FIG.
Is applied to a five-stacked disk stack type optical disk device, in which five optical disks 12 having recording layers 121, 121 respectively attached to the upper and lower surfaces of a plastic substrate 120, and a recording layer of each optical disk 12 And ten suspensions 33 for supporting the optical head 1 rotatably by a rotating shaft 44.
And a rotary linear motor 45 that drives the suspension 33. The recording layer 121 may be a phase change type medium or a magneto-optical type medium. Rotary linear motor 4
5 is a movable piece 45a to which the suspension 33 is connected.
And electromagnets 45c, 45c connected by a yoke 45b to drive the movable piece 45a. The structure of the optical head 1 is basically the same as that shown in FIG.
Transparent condensing medium 6 having a paraboloid of revolution and AlGalnN
A system laser (630 nm) is used, and the light spot diameter is 0.2 μm. The disc diameter is 12 cm, the track pitch and the mark length are 0.07 μm and 0.05, respectively.
μm, capacity on one side is 300 GB, and on both sides is 600
GB.

According to the optical disk device 100 of the ninth embodiment, information can be recorded on five optical disks 12, so that the capacity of 3 TB can be increased.

The optical head 1 shown in FIGS. 6 and 7 may be used. Thereby, the height of the optical head 1 is set to 3
mm or less, and the height of the optical disc device can be reduced.
Volume capacity can be increased.

FIG. 15 shows a main part of an optical disk device according to the tenth embodiment of the present invention. The optical disc apparatus 100 includes a plurality of (eg, eight) laser elements that can be driven independently, a semiconductor laser 2 that emits a plurality of laser beams 2 a from the plurality of laser elements, and a semiconductor laser 2.
A collimator lens 3 for shaping the laser beam 2a from the laser beam into a predetermined incident beam 2b ', a mirror 4 for reflecting the incident beam 2b' in a predetermined direction, and an objective lens 5 for converging the incident beam 2b 'reflected by the mirror 4. And the convergent light 2c ′ converged by the objective lens 5 enters,
b, which forms a plurality of light spots 9 in the same manner as in FIG. Membrane 7;
GeSbT is applied to one surface of the disc-shaped plastic plate 120.
e, a recording layer 121 made of the phase change material e is formed, and the optical disk 12 is rotated by a motor (not shown); And an eight-segment photodetector 15 for inputting the laser beam 2e via the condenser lens 14.

FIG. 16 shows the semiconductor laser 2. The semiconductor laser 2 is an edge emitting semiconductor laser and has an active layer 20.
a, a p-type electrode 20b and an n-type electrode 20c. By the distance d ₁ of the p-type electrode 20b, for example, 15 [mu] m, has a distance of laser beam 2a to 15 [mu] m.

FIG. 17 shows the light shielding film 7. The light shielding film 7
Eight micro holes 7a are provided corresponding to the number of laser beams 2a. The NA of the collimator lens 3 is 0.16, the NA of the transparent focusing medium 6 is 0.8, and the distance d between the laser beams 2a is d.
₁ is 15 μm, so that the light spot 9
Spacing, i.e., spacing d ₂ of microporous 7a are with 3 [mu] m. The array direction 7b of the micro holes 7a is
a is slightly inclined with respect to the track of the optical disk 12 so that a is located directly above each adjacent track. That is, the adjacent minute holes 7a are arranged so that the interval in the vertical direction with respect to the recording track is equal to the track pitch (in this case, 0.07 μm) p. Array axis direction 7b of micro holes 7a and tracks (not shown)
Is 23 milliradians. This inclination is adjusted by adjusting the inclination of the support in the laser array and by photolithography at the time of formation in the microhole array.

Next, the operation of the optical disk device 100 according to the tenth embodiment will be described. When a plurality of laser beams 2a are emitted from the semiconductor laser 2, the plurality of laser beams 2a from the semiconductor laser 2 are shaped into a predetermined incident beam 2b 'by the collimator lens 3, and then pass through the polarization beam splitter 13, The light is reflected by the mirror 4, converged by the objective lens 5, refracted by the incident surface 6 a of the transparent light-collecting medium 6, condensed, and condensed on the light-collecting surface 6 b. A plurality of light spots 9 are formed on the light collecting surface 6b. A plurality of near-field lights 10 ooze out of the transparent light-collecting medium 6 from the plurality of micro holes 7 a below the plurality of light spots 9, and the near-field light 10 propagates to the recording layer 121 of the optical disc 12 and emits light. Recording or optical reproduction is performed. The reflected light reflected by the optical disk 12 reverses the path of the incident light, is refracted by the incident surface 6a of the transparent light-collecting medium 6, is reflected by the mirror 4, and is separated from the incident beam 2b 'by the polarization beam splitter 13. After that, the light is condensed by the condensing lens 14 on the eight-divided photodetector 15.

According to the optical disk device 100 of the tenth embodiment, eight recording tracks are independently recorded simultaneously by eight independently modulatable near-field lights 10 from eight micro holes 7a. Recording and reproduction can be performed, and the transfer rate of recording and reproduction can be increased eight times. The length of the array of the micro holes 7a is about 20 μm, and the track bend between them is 0.007 μm, which is 1/1 of the track width.
Since it is about 0, the track shift due to this is negligible. Further, the number of the micro holes 7a is not necessarily limited to eight, but can be increased or decreased depending on the application. Note that the transparent light-collecting medium 6 may use the medium shown in another embodiment.
Also, irradiating a plurality of micro holes with one beam spot,
When using near-field light emitted from any of the micro holes,
The tracking frequency band can be reduced. Further, in the edge emitting semiconductor laser, as shown in FIG. 16, since the light emitting point is formed along the direction of the stacked surface of the active layer 20a, the direction in which the semiconductor laser is installed, in other words, the direction of the active layer is vertically set. The direction of the beam row to be applied changes depending on whether the beam is to be placed or placed horizontally. Note that, even with an edge emitting semiconductor laser having a single light emitting point, the beam shape is deformed depending on the direction of the active layer. And the polarization direction can be selected.

FIG. 18 shows an optical disk device according to the eleventh embodiment of the present invention. The optical head 1 of this optical disk device differs from the optical head 1 of FIG. 1 only in the outer diameter of the light-shielding film 7, and has the same configuration as the other. The light shielding film 7 has a diameter slightly larger than the diameter of the light spot. The optical disc 12 includes a protective film 12h, a recording layer 12i, an interference layer 12j, and a reflection layer 12k. In the case of the present embodiment, the total thickness of the protective film 12h, the recording layer 12i, the interference layer 12j, and the reflective layer 12k is about 100 nm, and the distance between the protective film 12h and the micro holes 7a is about 50 nm.

Next, the operation of the optical head 1 according to the eleventh embodiment will be described. Convergent light 2c from objective lens
Is refracted on the spherical incident surface 6a of the transparent light-collecting medium 6,
The refracted light 2d is converged on the converging surface 6b. A light spot 9 is formed on the light collecting surface 6b. The near-field light 10 leaking from the minute holes 7a of the light-shielding film 7 becomes propagating light and becomes
2 and is reflected by the reflection layer 12k of the optical disk 12. The reflected light 2k reflected by the reflection layer 12k not only passes through the minute holes 7a of the light shielding film 7 but also passes outside the light shielding film 7 and passes through the transparent light collecting medium 6 and the objective lens to the photodetector. Is entered.

The intensity distribution of the near-field light 10 from the minute holes 7a can be approximated as an intensity distribution 1 when the minute holes 7a are considered as a perfect diffusion surface in the recording medium. In this case, the spread is the largest, and the angular distribution is represented by Cos θ. This light is reflected toward the transparent light-collecting medium 6 by the reflection film 12k while maintaining this distribution. This light is applied to the micro holes 7a and the light shielding film 7
Assuming angles θ ₁ and θ _{2 at} which the outer shape of the micro hole 7a is assumed, respectively, the ratio I _r1 / I _{0 of the} light returning to the minute hole 7a and the ratio I _r2 / I ₀ returning to the peripheral portion are represented by Tn. If the medium reflectance is Rb, they can be approximated by the following equations (7) and (8), respectively.

(Equation 2)

(Equation 3) When the diameter of the micropores 7a is 50 nm, Tn is 0.1
5, Rb is about 0.2 for the phase change medium,
When the outer diameter of the light shielding film 7 is 0.2 μm, I _r1 / I ₀ ,
I _r2 / I ₀ becomes respectively 0.0025,0.02. That is, by taking in the light at the periphery of the light-shielding film 7, the intensity can be improved by about one digit. This effect increases as the diameter of the micro holes 7a decreases. Further, the light in the peripheral portion is refracted on the incident surface 6a of the transparent light-condensing medium 6 and enters the inside, and the return light from the minute hole 7a is
a, the directivity of the two is slightly different, but the diameter of the transparent light-condensing medium 6 is about 1 mm and the minute holes 7a
And the film thickness of the recording medium (150 nm) is sufficiently large, so that their deviation can be neglected, and it is possible to collectively introduce the two into the photodetector, thereby increasing the intensity of the reflected light. .

FIG. 19 shows a code error rate of 1 × 10 ^-9 during reproduction.
The relationship between the detected light power and the reproduction speed required to maintain the speed. In FIG. 19, the solid line shows the case where the duty ratio is 0.1, the broken line shows the case of 1, the line group A shows the case where the quantum efficiency of the photodetector is 0.1, and the line group B shows the case where it is 1. Since the detected light power of the present embodiment is about −30 dBm, the reproduction speed can be increased to 10 ⁹ bits / sec or more (Genichi Otsu, Electronics, May 1996, p.92). .

FIG. 20 shows an optical head of an optical disk device according to a twelfth embodiment of the present invention. FIG. 20A is a longitudinal sectional view, and FIG. 20B is a transverse sectional view. This optical head 1 is obtained by applying the optical head 1 shown in FIG. 8 to the optical disk device 100 shown in FIG. The optical head 1 has a flying slider 36 that floats on the optical disk 12. On the flying slider 36, an edge-emitting semiconductor laser 2 made of, for example, AlGalnP and emitting a laser beam 2 a having a wavelength of 630 nm, and a semiconductor A collimator lens 3 for shaping a laser beam 2a emitted from the laser 2 into a parallel beam 2b, a holder 37A made of a fused silica plate mounted on a flying slider 36, and a semiconductor laser 2
And a holder 37B made of a fused silica plate for fixing the collimator lens 3 on the holder 37A, a holder 37C for supporting the semiconductor laser 2 via the piezoelectric element 41, a parallel beam 2b from the semiconductor laser 2 and reflection from the optical disk 12. A polarizing beam splitter 13 for separating light, a quarter-wave plate 38 for converting linearly polarized light of the parallel beam 2b from the semiconductor laser 2 to circularly polarized light, a mirror 4 for reflecting the parallel beam 2b in the vertical direction, and a mirror 4 Parallel beam 2 reflected by
b for converging the upper transparent light-collecting medium 6 ″ shown in FIG.
A reflection layer 11 formed on the reflection surface 6e of the upper transparent light-condensing medium 6 "; a photodetector 15 attached to the seat plate 37A to input reflected light from the optical disk 12 via the beam splitter 13; The whole is housed in a head case 39, and the head case 39 is
It is fixed to the tip of the suspension 33. On the lower surface 36a of the flying slider 36, as shown in FIG.
The light-shielding film 7 having the minute holes 7a is formed by deposition.

According to the optical disc apparatus 100 of the twelfth embodiment, the near-field light that seeps out of the light spot 9 formed on the lower surface 36a of the flying slider 36 is narrowed by the minute holes 7a. As with the optical disc device 100 of the first embodiment, ultra-high density optical recording / light reproduction can be performed, and the optical head 1 can be downsized in the height direction. The optical head 1 is shown in FIGS.
4. The present invention may be applied to the optical disk device 100 shown in FIG. The optical head of the present invention may be of a so-called separation type in which a heavy portion such as a laser or a detecting portion is placed on a fixed portion, and only a lightweight element such as an objective lens and a folding mirror is mounted on a movable portion. However, as described above, in the optical head of the present invention, the light spot formed on the transparent light-collecting medium and the micro holes need to be aligned with high precision of 0.1 μm or less. At this time, in the separation type, it may be difficult to match the movable part and the fixed part with such accuracy due to the vertical movement of the optical disk, the movement of the movable part, and the distortion due to the temperature change. Therefore, it is preferable that at least the light emitting element and the transparent light-collecting medium are installed in the same housing and integrated. By doing so, it is possible to prevent displacement of the light spot and the minute hole due to fluctuation and distortion. The method of reading information recorded on an optical disk is not limited to the method of detecting reflected light as described in the embodiment, and the present invention is also applicable to a method of reading magnetism such as a known GMR (Giant Magnetic Resistive) sensor. Is of course applicable. Further, in the above-described embodiment, the optical functions such as the collimator lens, the reflecting mirror, the objective lens, and the upper transparent light-condensing medium are configured by one optical element. May be
At least a light-shielding film may be provided so that a light spot is formed by condensing light on the surface of the transparent light-condensing medium, and the microhole is located at that position. Further, when a spot is formed on the transparent light-collecting medium using a reflector, a gap may exist between the reflector and the transparent light-collecting medium. It is preferable that the body and the transparent light-collecting medium are in close contact with each other. Further, only the reflection film is shown as the reflector, but a member molded with metal may be used. However, considering the adhesion to the transparent light-collecting medium, the reflective film is more preferable. In the above-described embodiment, only the light-shielding film is shown as the light-shielding member. However, it is sufficient that the near-field leaks from the minute holes. The light may be blocked lightly. However, in view of the fact that the film thickness can be reduced and the precision of forming the micropores,
It is preferable to use a light shielding film.

[0067]

As described above, according to the present invention,
Since the near-field light oozing out of the transparent light-collecting medium from the light spot formed on the light-collecting surface is narrowed by the minute holes, the near-field light spot formed on the recording medium can be miniaturized. As a result, it is possible to increase the recording density of the recording medium. Also, place a micro hole at the spot position,
Since light is condensed on the transparent condensing medium and near-field light is obtained from the medium, high light use efficiency can be obtained. For this reason, it is possible to use a small and lightweight light source and photodetector, so that the optical head and the optical disk device can be reduced in size and the data transfer rate can be improved.

[Brief description of the drawings]

FIG. 1 is a diagram showing a main part of an optical head according to a first embodiment of the present invention.

FIG. 2A is a diagram illustrating a transparent light-collecting medium and a light-shielding film according to the first embodiment, and FIG. 2B is a bottom view thereof.

FIGS. 3A to 3D are views showing a method of forming a light-shielding film according to the first embodiment.

FIGS. 4A and 4B are diagrams showing modified examples of the light shielding film according to the first embodiment.

FIG. 5 is a diagram showing a main part of an optical head according to a second embodiment of the present invention.

FIG. 6A is a diagram showing a main part of an optical head according to a third embodiment of the present invention, and FIG. 6B is a bottom view thereof.

FIG. 7 is a diagram showing a main part of an optical head according to a fourth embodiment of the present invention.

FIG. 8A is a diagram showing a main part of an optical head according to a fifth embodiment of the present invention, and FIG. 8B is a diagram showing a light shielding film thereof.

9A is a diagram showing an optical disc device according to a sixth embodiment of the present invention, and FIG. 9B is a sectional view taken along line AA of FIG. 9A.

FIG. 10 is a diagram showing details of an optical disc according to a sixth embodiment.

FIG. 11 is a diagram showing an optical head according to a sixth embodiment.

FIGS. 12A to 12C are diagrams showing a main part of an optical head of an optical disk device according to a seventh embodiment of the present invention.

FIG. 13 is a diagram illustrating an optical disc device according to an eighth embodiment of the present invention.

FIG. 14 is a diagram illustrating an optical disc device according to a ninth embodiment of the present invention.

FIG. 15 is a diagram showing a main part of an optical disc device according to a tenth embodiment of the present invention.

FIG. 16 is a diagram showing a semiconductor laser according to a tenth embodiment.

FIG. 17 is a diagram showing a light shielding film according to a tenth embodiment.

FIG. 18 is a diagram showing a main part of an optical head of an optical disc device according to an eleventh embodiment of the present invention.

FIG. 19 is a diagram showing the relationship between detected light power and reproduction speed.

FIG. 20 (a) is a longitudinal sectional view of an optical head of an optical disk device according to a twelfth embodiment of the present invention, and FIG. 20 (b) is a transverse sectional view.

21A is a diagram showing a conventional optical disk device, and FIG.
Is a diagram showing the operation at the time of reproduction.

FIG. 22 is a diagram showing an optical head of another conventional optical disk device.

FIG. 23 is a diagram showing the relationship between the refractive index n and NA in FIG. 22;

FIG. 24 is a diagram showing an optical head.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Optical head 2 Semiconductor laser 2a Laser beam 2b Parallel beam 2b 'Incident beam 2c Convergent light 2c' Convergent light 2d Diffused light 2e Reflected light 3 Collimator lens 4 Mirror 5 Objective lens 6 Transparent condensing medium 6 ', 6 "Top transparent Light-collecting media 6a, 6'a Incident surface 6b Light-collecting surface 6c Center 6e Reflective surface 6d Bottom surface 6f Convex portion 6g Light-shielding film-coated surface 7 Light-shielding film 7a Micropore 8 Recording medium 8a Recording layer 9 Light spot 10 Near-field light DESCRIPTION OF SYMBOLS 11 Reflection film 12 Optical disk 12a Groove part 12b Land part 12h Protective film 12i Recording layer 12j Interference layer 12k Reflection layer 13 Polarization beam splitter 14 Condenser lens 15 Photodetector 20a Active layer 20b P-type electrode 20c N-type electrode 30 Rotation axis 31 Tracking direction 32 Linear motor 32a Fixed part 32b Moving coil 33 Suspension Option 33a Rotating shaft 34 Optical head drive system 35 Signal processing system 36 Floating slider 36a Condensing surface 36c Lower surface 36b Groove 36d Housing hole 37 Fused quartz plate 38 1/4 wavelength plate 39 Head case 40 Tracking direction 41 Piezoelectric element 42 Holder 43 , 45 Rotary linear motor 44 Rotating shaft 45a Movable piece 45b Yoke 45c Electromagnet 70 Photoresist film 70a Portion corresponding to micropores in photoresist film 70b Protection portion corresponding to periphery of light shielding film in photoresist film 71 Ti spacing p of film 100 optical disk device 120 plastic plate 121 recording layer 121a Al reflective film layer 121b SiO ₂ layer 121c GeSbTe recording layer 121d SiN layer 410 electrode terminals 411 electrode film 412 multilayer PZT thin film d ₁ laser beam interval d ₂ micropores Rack pitch θ angle of incidence

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[Procedure amendment]

[Submission date] February 7, 2000 (2000.2.7)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Name of invention

[Correction method] Change

[Correction contents]

[Entitled] optical head, disk device, method of manufacturing a contact and optical head

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] Claims

[Correction method] Change

[Correction contents]

[Claims]

5. Before SL transparent condensing medium, said laser beam emitting
Structure from a part of a spherical surface that refracts the laser beam from the means
Comprising a made the incident surface, from the center r / n (r of the spherical
Is the radius of the spherical surface, and n is the refractive index of the transparent light-collecting medium.
The optical head according to claim 1, wherein the light-collecting surface is formed at the position of (b).

8. Before SL transparent condensing medium has a concave spherical incident surface on which the laser beam from the laser beam emitting unit is incident, reflection film is formed around the entrance surface, the incident incident on the surface, light according to claim 1, wherein the configuration that includes a non-spherical reflecting surface of the laser light reflected is reflected by the reflective film to form the light spot in the focusing plane by the light shielding member head.

Said micropores wherein said light shield according to claim 1 optical head according configurations having small consisting opening width than the wavelength of the laser beam.

Wherein said transparent condensing medium is due to the piezoelectric element
2. The optical head according to claim 1 , wherein the optical head is moved .

Wherein said transparent condensing medium comprises a first transparent medium and a second transparent medium in close contact with each other, the first
The transparent medium has an incident surface on which the laser light is incident.
The second transparent medium includes the light-collecting surface and the projection.
2. The optical head according to claim 1 , wherein the optical head has a different configuration .

Wherein said second transparent medium, 請 Motomeko 11 optical head according that make up at least part of the flying slider which flies above the optical disc in accordance with rotation of the optical disk.

14. The first transparent medium and the second transparent medium.
The optical head according to claim 11 , wherein the body has substantially the same refractive index.

16. The optical head according to claim 15 , wherein said reflection surface forms a part of a paraboloid of revolution.

18. The reflective surface is constituted by the plane, the reflector, the optical head according to claim 15, wherein the structure wherein is a reflective hologram formed on the plane.

The incident surface and the converging surface of 19. The transparent condensing medium has claim 15 optical head according the configuration ing from a plane perpendicular to each other.

20. A laser light emitting means, comprising: a laser light source that emits the laser light; and the laser light from the laser light source is shaped into parallel light to be incident on the incident surface of the transparent condensing medium. 16. The optical head according to claim 15 , comprising a collimator lens.

21. The laser beam emitting means, claim 15 of the structure active layer with the placed edge-emitting semiconductor laser so as to be perpendicular to the focus plane of the transparent condensing medium
Optical head as described.

54. A laser beam emitting means for emitting a laser beam.
And injects the laser light from the laser light emitting means and focuses the laser light.
The light spot of the laser light is formed by condensing on the surface
A transparent light collecting medium, provided on the transparent light collecting medium,
The micro holes having a small area are located at the position where the light spot is formed.
And a light-shielding member provided at a position where the light- shielding member has a thickness smaller than the wavelength of the laser light.
Recording or using near-field light oozing from the micropores
An optical head for performing reproduction .

55. Laser light emitting means for emitting laser light
And injects the laser light from the laser light emitting means and focuses the laser light.
The light spot of the laser light is formed by condensing on the surface
A transparent light collecting medium, provided on the transparent light collecting medium,
The micro holes having a small area are located at the position where the light spot is formed.
A light-shielding body provided at a position, wherein the light-shielding body is inclined at least around the micro-hole with respect to a plane perpendicular to the main optical axis of the laser beam in the micro-hole and exuded from the micro-hole. Using near-field light
Optical head characterized in that to perform recording or reproducing Te.

56. An optical head according to claim 55, wherein said transparent light-collecting medium has a plurality of minute irregularities for light scattering at least around said minute holes.

57. A rotating optical disk, and irradiating near-field light on the optical disk to transfer information to the optical disk .
An optical head for recording or reproducing, and an optical head
The optical head comprises a laser beam emitting unit for emitting a laser beam.
And injects the laser light from the laser light emitting means and focuses the laser light.
The light spot of the laser light is formed by condensing on the surface
A transparent light collecting medium, provided on the transparent light collecting medium,
The micro holes having a small area are located at the position where the light spot is formed.
And a light-shielding body provided in the transparent light-collecting medium,
The incident surface on which the laser light is incident and the incident light on the incident surface
The laser beam is reflected to form the light spot on the light-collecting surface.
A reflective surface to be formed,
A disk device for performing recording or reproduction using field light .

58. A plurality of rotating optical discs arranged coaxially at predetermined intervals, and near-field light irradiating the plurality of optical discs to record information on the optical discs .
A plurality of optical heads for performing recording or reproduction;
A disk drive comprising: a drive unit for driving a head ; wherein the optical head comprises a laser beam emitting unit for emitting a laser beam.
And injects the laser light from the laser light emitting means and focuses the laser light.
The light spot of the laser light is formed by condensing on the surface
A transparent light collecting medium, provided on the transparent light collecting medium,
The micro holes having a small area are located at the position where the light spot is formed.
And a light-shielding body provided in the transparent light-collecting medium,
The incident surface on which the laser light is incident and the incident light on the incident surface
The laser beam is reflected to form the light spot on the light-collecting surface.
A reflective surface to be formed,
A disk device for performing recording or reproduction using field light .

59. A transparent light-collecting medium having a light-collecting surface on which a light spot is formed by incident laser light, and a photoresist having a width smaller than the light spot is formed on the transparent light-collecting medium. A concave portion is formed by removing a region of the transparent light-collecting medium where the photoresist is not present by etching at a predetermined depth equal to or less than the wavelength of the laser beam, and forming a concave portion, and depositing a light shielding material in the concave portion to form the small width. A method of manufacturing an optical head, comprising forming a light shielding body having fine holes.

60. The method of manufacturing an optical head according to claim 59 , wherein the step of forming the photoresist includes the step of forming a photoresist for determining a shape of the light shielding body on an outer edge of the transparent light-collecting medium.

61. The method of manufacturing an optical head according to claim 59 , wherein the step of forming the recess includes the step of forming a plurality of minute unevenness for light scattering on the seating surface of the recess.

62. The method of manufacturing an optical head according to claim 59 , wherein the step of forming the recess includes the step of forming a seating surface of the recess on an inclined surface.

63. The method of manufacturing an optical head according to claim 59 , wherein the step of forming said light shield includes a step of performing an etching step from said light-collecting surface side of said transparent light-collecting medium.

[Procedure amendment 3]

[Document name to be amended] Statement

[Correction target item name] 0001

[Correction method] Change

[Correction contents]

[0001]

The present invention relates to an optical head utilizing the near-field optical disk apparatus, a method of manufacturing a contact and optical head, in particular, it is possible to increase the recording density of the recording medium,
The present invention relates to an optical head, a disk device , and a method for manufacturing an optical head, which are reduced in size and improved in data transfer rate.

[Procedure amendment 4]

[Document name to be amended] Statement

[Correction target item name] 0016

[Correction method] Change

[Correction contents]

[0016] Therefore, an object of the present invention, it is possible to increase the recording density of the recording medium, an optical head with improved size and data transfer rate, the disk device, to provide a method of manufacturing a contact and optical head It is in.

[Procedure amendment 5]

[Document name to be amended] Statement

[Correction target item name] 0017

[Correction method] Change

[Correction contents]

[0017]

In order to achieve the above object, the present invention provides a laser light emitting means for emitting laser light,
Incident pre SL laser beam emitting unit or al before Symbol laser light, converging light
The light spot of the laser light is formed by condensing on the surface
A transparent light- collecting medium, provided on the transparent light-collecting medium,
Micropores having a smaller area than the light spot and a light shielding member provided on the forming position of the light spot, the
The transparent light-collecting medium projects from the light-collecting surface into the minute hole.
Using a near-field light oozing from the convex portion
Provided is an optical head characterized in that recording or reproduction is performed by using the same. The present invention provides a laser
Laser light emitting means for emitting light, and the laser light emitting means
The laser light is incident from the step, and is focused on the light collecting surface,
A transparent condensing medium on which a light spot of laser light is formed,
Provided on the transparent light-collecting medium, from the light spot
The micro holes having a small area are located at the position where the light spot is formed.
And a light-shielding member provided in the transparent condensing medium,
An input into which the laser light from the laser light emitting means enters
Launch surface, reflecting the laser light incident on the entrance surface
A reflecting surface for forming the light spot on the light collecting surface.
Recording or using near-field light oozing from the micropores
Provided is an optical head characterized by performing reproduction.
The present invention achieves the above object by emitting parallel laser light.
Laser light emitting means for emitting light, and
Is incident along the recording surface of the recording medium.
And focuses light on a light-collecting surface facing the recording surface of the recording medium.
Transparent condensing medium on which the light spot of the laser light is formed
A light source provided on the transparent light-collecting medium;
Micro-holes with an area smaller than the shape of the light spot
A light-shielding body provided at the formation position,
The body receives the parallel laser light from the laser light emitting means.
Incident surface for incidence, and parallel laser light incident on the incident surface
To form the light spot on the light-collecting surface
A reflective surface, and uses near-field light oozing out of the micropores.
Optical head for recording or reproducing
I will provide a. The present invention provides a laser
Laser light emitting means for emitting the light;
The laser light is incident from the
A transparent condensing medium on which a light spot of the laser light is formed
And the light spot provided on the transparent light-collecting medium.
A small rectangular hole with a smaller area is
A light shielding body provided at a position where
Recording or reproduction using near-field light oozing from
An optical head is provided. The present invention
Laser that emits multiple laser beams to achieve the purpose
Light emitting means, and the plurality of lasers from the laser light emitting means.
Laser light is incident and focused on the light-collecting surface to form the plurality of lasers.
A transparent condensing medium on which a light spot of light is formed;
Provided on a medium for bright light collection and smaller than the light spot
A plurality of small holes having an area form the plurality of light spots.
A light-shielding body provided at the formation position;
Recording or reproduction using multiple near-field light oozing from
An optical head is provided. The present invention
Is a laser that emits laser light to achieve the above object.
The light emitting means, and the laser
Light is incident, is focused on the light-collecting surface, and is
A transparent light-collecting medium on which a slot is formed;
Irradiating near-field light from the light-collecting surface of the medium for bright light collection,
The reflected light reflected on the recording medium is transmitted through the transparent condensing medium.
Detecting means for detecting a signal by inputting the
Provided on a transparent light-collecting medium and smaller than the light spot
A small hole with a large area is provided at the position where the light spot is formed.
And larger than the size of the light spot
A light-shielding body having an outer shape;
Passing through the inside of the micropores and the outside of the outline
Provided is an optical head characterized by inputting to a detection means.
I do. The present invention provides a laser light for achieving the above object.
A laser light emitting means for emitting the laser light;
The laser light is incident from the
A transparent condensing medium on which a light spot of the light is formed;
Provided on a transparent light-collecting medium and smaller than the light spot
A small hole with a large area is provided at the position where the light spot is formed.
A light-shielding body, and the light-shielding body is provided with the laser light.
Having a thickness smaller than the wavelength of
Recording or reproduction is performed using near-field light.
To provide an optical head. The present invention achieves the above object.
Laser light emitting means for emitting laser light;
The laser light is incident from the laser light emitting means, and is
To form a light spot of the laser beam
A light-collecting medium, provided on the transparent light-collecting medium,
The micro holes having an area smaller than the light spot
A light-shielding body provided at a position for forming the light-shielding unit.
The body comprises the micropores at least around the micropores;
Tilted with respect to a plane perpendicular to the main optical axis of the laser light at
Recording or recording using near-field light sloping and exuding from the micropores
Provides an optical head characterized by performing reproduction
You. In order to achieve the above object, the present invention provides a rotating optical disc and an optical disc that irradiates near-field light onto the optical disc and records or reproduces information on the optical disc .
A disk device comprising a head and a driving unit for driving the optical head , wherein the optical head emits a laser beam.
A laser beam emitting unit that emits light,
The laser light is incident and focused on the light-collecting surface to form the laser light.
A transparent condensing medium on which a light spot is formed,
A surface provided on the light-collecting medium and smaller than the light spot
A microhole having a product is provided at a position where the light spot is formed.
A transparent light-condensing medium,
An incident surface on which the laser light from the light emitting means is incident,
The laser beam incident on the incident surface is reflected on the condensing surface.
A reflecting surface for forming the light spot,
Performs recording or reproduction using near-field light oozing from the stoma
The invention provides a disk device characterized by having In order to achieve the above object, the present invention provides a transparent light-collecting medium having a light-collecting surface on which a light spot is formed by incident laser light, and the transparent light-collecting medium has a width smaller than the light spot. A photoresist is formed, and a region where the photoresist is not present in the transparent light-collecting medium is removed by etching at a predetermined depth equal to or less than the wavelength of the laser beam to form a concave portion, and a light shielding material is deposited on the concave portion. it that provides manufacturing method for an optical head, characterized in that to form a light shield having a small hole of the small consisting width by.

 ────────────────────────────────────────────────── ─── Continued on the front page F term (reference) 5D119 AA11 AA22 AA43 BA01 BB01 BB02 BB04 BB05 CA06 DA01 DA05 FA05 FA20 FA21 JA02 JA34 JA43 JA44 JA47 JA48 JB03 JB06 MA06 NA05

Claims (73)

[Claims] 1. A laser light emitting means for emitting laser light, and a transparent light-collecting medium, wherein the laser light from the laser light emitting means is focused on a light-collecting surface of the transparent light-collecting medium. An optical system that forms a light spot by using a light-shielding member that is provided on the transparent light-collecting medium and has a small hole having an area smaller than the light spot and that is provided at a position where the light spot is formed. Optical head featuring. 2. A laser beam emitting means for emitting a laser beam, a focusing optical system for focusing the laser beam from the laser light source, and a light spot formed by the laser beam focused by the focusing optical system. A transparent light-gathering medium having a light-gathering surface to be formed, and a light-shielding body provided on the transparent light-gathering medium and provided with a micropore having an area smaller than the light spot at a position where the light spot is formed. An optical head comprising: 3. An optical head according to claim 2, wherein said condensing optical system is an optical lens provided at a position separated from said transparent condensing medium. 4. An optical head according to claim 2, wherein said condensing optical system is a reflector. 5. The optical head according to claim 4, wherein said reflector is provided on a surface of said transparent light-collecting medium. 6. The optical head according to claim 2, wherein the transparent light-collecting medium is a solid immersion lens. 7. The light-collecting optical system is an objective lens, and the transparent light-collecting medium is formed of a part of a spherical surface, and an incident surface on which the laser light condensed by the objective lens is incident. The optical head according to claim 2, wherein the light-collecting surface is formed on an axis passing near the center of the spherical surface. 8. An optical head according to claim 2, wherein said transparent light-collecting medium has an optical power on a surface on which said laser light is incident. 9. An optical head according to claim 2, wherein said transparent light-collecting medium is a super solid immersion lens. 10. The condensing optical system is an objective lens, and the transparent condensing medium is formed of a part of a spherical surface, and the laser light condensed by the objective lens is incident thereon, An incident surface for refracting the laser light, and the light-collecting surface is positioned at r / n (r is the radius of the spherical surface, n is the refractive index of the transparent light-collecting medium) from the center of the spherical surface. 3. The optical head according to claim 2, wherein the optical head is formed. 11. The transparent light-collecting medium, wherein the surface on which the laser light is incident has a concave shape that diverges the incident laser light. 3. The laser light, which is provided from the incident position of the laser light via the transparent light-collecting medium and converges the laser light diverged on a surface on which the laser light is incident.
Optical head as described. 12. The light-collecting optical system is a reflective film, and the transparent light-collecting medium has a concave spherical incident surface on which the laser light from the laser light emitting means enters, The reflective film is formed around the light incident on the incident surface,
The optical head according to claim 2, further comprising: an aspherical reflecting surface that forms the light spot on the light-collecting surface by reflecting the laser light reflected by the light-shielding body on the reflecting film. 13. The light-collecting optical system is provided at least through the transparent light-collecting medium at a position on the transparent light-collecting medium where the laser light is incident, and a direction in which the incident laser light is incident. 3. The optical head according to claim 2, wherein the light spot is formed on the transparent light-collecting medium by changing an optical path in a direction intersecting the light spot. 14. An optical head according to claim 13, wherein said condensing optical system is a reflector. 15. The optical head according to claim 13, wherein the transparent light-collecting medium has a flat surface on which the laser light is incident. 16. The optical head according to claim 13, wherein said incident surface and said light-collecting surface of said transparent light-collecting medium are each formed of a plane and are orthogonal to each other. 17. The light-collecting optical system is a reflective film, and the transparent light-collecting medium is formed by a flat incident surface on which the laser light from the laser light emitting means is incident and the reflective film. The optical head according to claim 2, further comprising: a reflecting surface configured to reflect the laser light incident on the incident surface with the reflective film and form the light spot on the condensing surface. 18. An optical head according to claim 17, wherein said reflection surface forms a part of a paraboloid of revolution. 19. An optical head according to claim 17, wherein said reflection surface is formed of a flat surface, and said reflection film is a reflection type hologram formed in a planar shape. 20. An optical head according to claim 19, wherein said reflection hologram is constituted by a volume hologram. 21. The optical head according to claim 19, wherein said reflection hologram is constituted by an uneven binary hologram. 22. A laser beam emitting unit for emitting a laser beam, a focusing optical system for focusing the laser beam from the laser beam emitting unit, and a laser beam focused by the focusing optical system. A transparent light-gathering medium having a light-gathering surface on which a spot is formed; An optical head comprising a body. 23. A laser light emitting means for emitting laser light, a transparent light-collecting medium having a light-collecting surface on which the laser light is focused and a light spot is formed by the focused laser light; An optical head, comprising: a light-shielding member provided on the transparent light-collecting medium and having a fine hole having an area smaller than the light spot at a position where the light spot is formed. 24. The optical head according to claim 23, wherein said transparent light-collecting medium has an optical power on an incident surface of said laser beam. 25. A medium according to claim 2, wherein said transparent light-collecting medium is a super solid immersion lens.
3. The optical head according to 3. 26. The light-collecting optical system includes an objective lens disposed apart from the transparent light-collecting medium, wherein the transparent light-collecting medium is formed of a part of a spherical surface, and is formed by the objective lens. The laser beam condensed is incident thereon, and has an incident surface for refracting the incident laser beam. From the center of the spherical surface, r / n (r is the radius of the spherical surface, and n is 23. The optical head according to claim 22, wherein the light-collecting surface is formed at a position (refractive index of the medium). 27. The transparent light-collecting medium according to claim 1, wherein the transparent light-collecting medium has a refractive index larger than 1.
Optical head according to the item. 28. An optical head according to claim 1, wherein said transparent light-collecting medium is made of heavy flint glass. 29. The method according to claim 1, wherein the transparent light-collecting medium is a crystalline material.
Optical head according to the item. 30. The optical head according to claim 1, wherein the minute hole of the light shielding body has an opening width smaller than a wavelength of the laser beam. 31. A light shielding film having a thickness smaller than a wavelength of the laser light.
0. The optical head according to claim 1. 32. The optical head according to claim 1, wherein the light shield is embedded in the transparent light-collecting medium. 33. The transparent light-collecting medium according to claim 1, wherein the transparent light-collecting medium has a convex portion which is located inside the minute hole and has a tip as a light-collecting surface. Optical head as described. 34. The optical head according to claim 33, wherein a tip portion of said convex portion and a surface of said light shielding body are substantially flat. 35. The light-shielding body according to claim 35, wherein the light-shielding body is formed by performing an etching step for forming micro holes from the light-collecting surface side of the transparent light-collecting medium. The optical head according to any one of claims 1 to 34. 36. The laser beam emitting unit emits a single laser beam, and the light shield includes a plurality of micro holes at a position where the single laser beam is formed by the single laser beam. The optical head according to any one of claims 1 to 35 having a configuration having the optical head. 37. A structure in which said laser beam emitting means emits a plurality of said laser beams, and said light shielding body has said micro holes respectively corresponding to positions where said plurality of light spots are formed by said plurality of laser beams. The optical head according to any one of claims 1 to 36. 38. The light according to claim 1, wherein the light-collecting surface of the transparent light-collecting medium and the main optical axis of the laser beam are orthogonal to each other in the microhole. head. 39. The transparent light-collecting medium according to claim 1, wherein the medium is inclined at least around the micro-hole with respect to a plane perpendicular to the main optical axis of the laser beam in the micro-hole. The optical head according to claim 38. 40. The optical head according to claim 1, wherein the transparent light-collecting medium has a plurality of minute irregularities for scattering light at least around the minute holes. . 41. The transparent light-condensing medium comprises a first transparent medium and a second transparent medium which are in close contact with each other, and the laser beam is incident on the first transparent medium to form the light spot. 41. The optical head according to claim 1, wherein the light-collecting surface is located on the second transparent medium. 42. The second transparent medium forms at least a part of a flying slider that floats on the optical disk with rotation of the optical disk.
2. The optical head according to 1. 43. The second transparent medium has a convex portion located in the minute hole, and the tip of the convex portion and the bottom surface of the floating slider closest to the optical disk are on the same plane. 43. The optical head according to claim 42, wherein the optical head is formed so as to operate. 44. The optical head according to claim 41, wherein said first transparent medium and said second transparent medium have substantially the same refractive index. 45. The optical head according to claim 1, wherein said laser light emitting means includes a semiconductor laser for emitting said laser light. 46. The optical head according to claim 45, wherein said semiconductor laser is an edge emitting semiconductor laser. 47. The optical head according to claim 46, wherein the edge emitting semiconductor laser has a configuration in which an active layer is disposed so as to be perpendicular to the light-collecting surface of the transparent light-collecting medium. 48. The optical head according to claim 46, wherein said edge-emitting semiconductor laser has an active layer disposed so as to be parallel to said light-collecting surface of said transparent light-collecting medium. 49. The optical head according to claim 45, wherein said semiconductor laser is a surface-emitting type semiconductor laser. 50. A collimator lens provided on the main optical axis of the laser light between the laser light emitting means and the transparent condensing medium, and for shaping the laser light from the laser light source into parallel light. Claims 1 to 4 having a configuration including:
10. The optical head according to any one of claims 9 to 10. 51. The laser light emitting means includes a laser light source for emitting the laser light, and a collimating lens for shaping the laser light from the laser light source into parallel light and causing the laser light to enter the condensing optical system. 3. The optical head according to claim 2, wherein the optical head has a configuration. 52. The laser light emitting means, and a laser light source for emitting the laser light, and the laser light from the laser light source is shaped into parallel light to be incident on the incident surface of the transparent light-collecting medium. The optical head according to claim 23, comprising a collimator lens. 53. The optical head according to claim 1, further comprising a piezoelectric element for moving the transparent light-collecting medium. 54. The optical head according to claim 1, wherein at least the laser beam emitting means and the transparent light-collecting medium are fixed on a same housing. 55. The optical disk according to claim 1, wherein the optical disk is a rotating optical disk and a disk device that irradiates near-field light onto the optical disk to detect information recorded on the optical disk. A disk device, comprising: a head; and driving means for driving the optical head. 56. A disk drive according to claim 55, further comprising a detecting means for detecting a recording signal obtained by irradiating said optical disk with said near-field light. 57. The disk device according to claim 55, further comprising the flying slider provided with at least the transparent light-collecting medium of the optical head and the laser light emitting device. 58. The transparent light-collecting medium is composed of a first transparent medium and a second transparent medium that are in close contact with each other, and the laser light is incident on the first transparent medium to form the light spot. The light-collecting surface is located on the second transparent medium, and the second transparent medium constitutes at least a part of a flying slider that floats on the optical disk with rotation of the optical disk. Claim 5
6. The disk device according to 5. 59. The disk device according to claim 55, wherein a detecting means for detecting a recording signal obtained by irradiating the optical disk with the near-field light is provided on the flying slider. 60. The disk device according to claim 55, wherein said optical disk is a read-only medium on which information is recorded by a concave / convex pit row. 61. A disk drive according to claim 55, wherein said optical disk is a magneto-optical recording medium. 62. A disk drive according to claim 55, wherein said optical disk is a light phase change recording medium. 63. The disk device according to claim 55, wherein said optical disk is a write-once recording medium that forms uneven bits by light absorption of a dye. 64. A detecting means for detecting a recording signal obtained by irradiating the optical disk with the near-field light, wherein the light shield is a light reflected from the near-field light irradiated on the optical disk. 55. The disk device according to claim 55, wherein the disk device has a configuration in which the laser beam passes through the outside of the light blocking member in addition to the inside of the minute hole and is input to the detection means. 65. The light-collecting optical system is a reflection film, and the transparent light-collecting medium has a concave spherical incident surface on which the laser light from the laser light emitting means enters, The reflective film is formed around the light incident on the incident surface,
56. The disk device according to claim 55, further comprising: an aspherical reflecting surface for forming the light spot on the light-collecting surface by reflecting the laser beam reflected by the light shielding body on the reflecting film. 66. A plurality of rotating optical disks arranged coaxially at predetermined intervals, and near-field light spots formed on the plurality of optical disks to detect information recorded on the optical disks. 55. A disk device, comprising: a plurality of optical heads according to any one of claims 1 to 54; and detection means for detecting a recording signal obtained by irradiating the optical disk with the near-field light spot. A disk device characterized by the above-mentioned. 67. A transparent light-collecting medium having a light-collecting surface on which a light spot is formed by incident laser light, and a photoresist having a width smaller than the light spot is formed on the transparent light-collecting medium. A concave portion is formed by removing a region of the transparent light-collecting medium where the photoresist is not present by etching at a predetermined depth equal to or less than the wavelength of the laser beam, and forming a concave portion, and depositing a light shielding material in the concave portion to form the small width. A method of manufacturing an optical head, comprising: forming a light shield having an opening. 68. The method of manufacturing an optical head according to claim 67, wherein said step of forming a photoresist includes a step of forming a photoresist for determining a shape of said light shielding body on an outer edge of said transparent light-collecting medium. 69. The method of manufacturing an optical head according to claim 67, wherein the step of forming the concave portion includes the step of forming a plurality of minute irregularities for light scattering on the seating surface of the concave portion. 70. The method of manufacturing an optical head according to claim 67, wherein the step of forming the recess includes the step of forming a seating surface of the recess on an inclined surface. 71. The method of manufacturing an optical head according to claim 1, wherein the collection of the transparent light-collecting medium is performed during the step of forming the light shield. A method for manufacturing an optical head, comprising a step of performing an etching step from an optical surface side. 72. An optical element used for an optical head, wherein an incident surface on which laser light is incident, a light spot formed by condensing the laser light are formed, and a convex portion having a width shorter than the diameter of the light spot. An optical element comprising: 73. The optical element according to claim 72, further comprising a light shield provided on a peripheral edge of said projection.