JP2001110090A - Recording medium and method of manufacturing the same, as well as optical information recording and reproducing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a recording medium having characteristics not in a near- field optical head but in the structure of the recording medium in order to enhance the utilization efficiency of light in an optical memory using near-field light, and a method for manufacturing the same as well as an optical information recording and reproducing device using the recording medium. SOLUTION: The recording medium 6 for recording and reproducing information by the near-field optical head utilizing the near-field optical light consists of a medium substrate transparent to the wavelength of irradiation light to be cast for the purpose of forming the near-field light, a data recording part 33 for recording the information on a medium substrate surface and a light condensing structure for condensing the irradiation light to the data recording part 33. More particularly the light condensing structure comprises tapered parts 32 having reflection films formed and light shielding parts 34.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recording medium capable of reproducing and recording high-density information using near-field light, a method of manufacturing the same, and an optical information recording / reproducing apparatus.

[0002]

2. Description of the Related Art In order to observe a minute area on the order of nanometers on a sample surface, a scanning tunneling microscope (S) is used.
TM) and a scanning probe microscope (SPM) represented by an atomic force microscope (AFM). SPM
Scans a probe with a sharpened tip on the sample surface, and observes the interaction between the probe and the sample surface, such as tunneling current and atomic force, to obtain an image with a resolution that depends on the probe tip shape. Can be obtained, but the restrictions on the sample to be observed are relatively severe.

Attention has been paid to a near-field optical microscope which enables observation of a minute area on the surface of a sample by observing an interaction between the near-field light generated on the surface of the sample and the probe. Have been. In the near-field optical microscope, the near-field light is generated by irradiating the surface of the sample with the propagating light, and the generated near-field light is scattered by a probe having a sharpened tip. By performing the same processing as the detection, the limit of the observation resolution by the conventional optical microscope is overcome, and observation of a finer area is enabled. In addition, by sweeping the wavelength of light applied to the sample surface, it is possible to observe the optical properties of the sample in a minute area.

[0004] In addition to the use as a microscope, near-field light having a high energy density is generated at a small aperture of the optical fiber probe by introducing relatively high-intensity light toward the sample through the optical fiber probe. Application as high-density optical memory recording in which the structure or physical properties of the sample surface is locally changed by light is also possible.

As a probe used in a near-field optical microscope, for example, as disclosed in US Pat. No. 5,294,790, an opening penetrating therethrough is formed in a silicon substrate by a semiconductor manufacturing technique such as photolithography. A cantilever-type optical probe has been proposed in which an insulating film is formed on one surface of a substrate and a conical optical waveguide layer is formed on the insulating film on the opposite side of the opening. In this cantilever type optical probe, an optical fiber is inserted into an opening, and light can be transmitted through a minute opening formed by coating a portion other than the tip of the optical waveguide layer with a metal film.

Further, it has been proposed to use a flat probe having no sharpened tip like the probe described above. The flat probe is formed by forming an opening having an inverted pyramid structure in a silicon substrate by anisotropic etching, and its apex has a diameter of several tens of nanometers and is penetrated. Such a planar probe can be easily formed into a plurality on the same substrate by using a semiconductor manufacturing technique, that is, it can be easily arrayed, and can be used as an optical memory head particularly suitable for reproduction and recording of an optical memory using near-field light. . As an optical head using this flat probe, a flying head conventionally used in a hard disk and having a flat probe has been proposed. The flying head is aerodynamically designed to fly about 50 to 100 nm from the recording medium. By forming a minute opening on the recording medium side of this flying head, near-field light can be generated to perform optical recording and reproduction.

[0007]

However, an optical memory using near-field light can realize an ultra-high-density optical memory having a diffraction limit equal to or less than the diffraction limit of light because it uses near-field light. There is a problem that the efficiency is low and the amount of light received by the light receiving element is very weak. In order to solve this problem, conventionally, the intensity of the laser light used has been increased, or a ball lens or the like has been filled in the inverted pyramid structure of a flat probe which is a near-field optical head.

However, when the intensity of the laser beam is increased, new problems such as heat generation and power consumption are caused. In addition, when a ball lens is used, it is necessary to align the ball lens, which causes an increase in cost. Further, there is a problem that it is difficult to focus light on an opening in all near-field optical heads when mass production is performed due to individual variations of ball lenses.

Therefore, when realizing an ultra-high-density memory using near-field light, it is difficult to reduce the size and power consumption and reduce the price by mass production. Therefore, the present invention provides a recording medium characterized by the structure of a recording medium, not a near-field optical head, and a method of manufacturing the same, in order to increase the light use efficiency and solve the above-described problems of the conventional method. It is an object to provide an optical information recording / reproducing device using a recording medium.

[0010]

Therefore, in order to solve the above-mentioned problems, a first recording medium according to the present invention is a recording medium for recording and reproducing information with a near-field optical head using near-field light. , A medium substrate transparent to the wavelength of the irradiation light irradiated to generate near-field light, a data recording unit for recording information on the medium substrate surface, and condensing the irradiation light on the data recording unit And a light-collecting structure.

According to the present invention, since the recording medium has a condensing structure for condensing the irradiation light radiated from the outside to the data recording unit, the light converging effect of the condensing structure irradiates the data recording unit with the light. As a result, stronger near-field light is generated in the data recording unit, and the intensity of propagating light obtained by interacting the near-field light with the near-field optical head increases.

Further, a second recording medium according to the present invention comprises:
In the first recording medium, the light-condensing structure includes a tapered portion having a reflective film having a tapered shape in the thickness direction of the medium substrate, and a light-shielding portion for shielding irradiation light in a region other than the data recording portion. It is characterized by. According to the invention,
Since the recording medium can be formed by transfer by making the condensing structure tapered, mass production of the recording medium is possible and cost reduction is easy.

Further, a third recording medium according to the present invention comprises:
The first or second recording medium is characterized in that the reflection film also serves as a light shielding portion. According to the present invention, the reflection film formed on the tapered portion and the light-shielding portion become the same, and the number of steps for manufacturing the recording medium is reduced by one, so that the cost can be further reduced. In the fourth recording medium according to the present invention, in the first recording medium, the data recording portions are formed on both sides of the medium substrate, and the light-collecting structure has a reflection film having a tapered shape in the thickness direction of the medium substrate. It is a formed tapered portion.

According to the present invention, since the data recording portions can be formed on both sides of the recording medium, the capacity per recording medium can be doubled. The fifth recording medium according to the present invention is the same as the second or fourth recording medium, except that the tapered portion in which the reflective film having the tapered shape is formed in the thickness direction of the medium substrate is formed by the reverse of the tapered portion in which the reflective film is formed. It is characterized in that it is a cone-shaped tapered portion.

According to the present invention, since the shape of the tapered portion is an inverted quadrangular pyramid shape, the irradiation light can be efficiently focused on the data recording portion by the four slopes of the tapered portion on which the reflection film is formed. . Therefore, the light beam from the light source can be used more efficiently. The sixth recording medium according to the present invention is the recording medium according to the second or fourth recording medium, wherein the tapered portion in which the reflection film having the tapered shape is formed in the thickness direction of the medium substrate has a V in which the reflection film is formed. It is a groove-shaped tapered portion.

According to the present invention, it is possible to perform tracking control using a data recording section formed concentrically, and to perform more stable signal reproduction. Further, a first method for manufacturing a recording medium according to the present invention includes a convex shape forming step of forming a convex shape in a recording medium for recording and reproducing information with a near-field optical head using near-field light; Transferring the image to a medium substrate,
The method is characterized in that the method comprises a step of forming a reflective film and a light-shielding portion in which a reflective film and a light-shielding portion are formed in a concave shape created by the transfer process.

According to the present invention, a medium substrate having a tapered shape can be formed by transfer. Therefore, once a mold is formed, mass transfer of a recording medium can be performed by transferring, and a low volume can be obtained. Cost reduction is easy. Further, a second method for manufacturing a recording medium according to the present invention includes a concave shape forming step of forming a concave shape in a recording medium for recording and reproducing information with a near-field optical head using near-field light; And forming a reflection film and a light shielding portion.

According to the present invention, in addition to the effect of the first method for manufacturing a recording medium according to the present invention, the step of forming a mold can be eliminated, so that the cost can be reduced accordingly. Also, a first optical information recording / reproducing apparatus according to the present invention is an optical information reproducing apparatus for reproducing information by a near-field optical head using near-field light, wherein the near-field light composed of a light source and a lens is used. An irradiation optical system that is irradiated to generate the light, a medium substrate that is transparent to the wavelength of the irradiation light, and a data recording unit on the surface of the medium substrate on which information to be recorded / reproduced is formed. It is characterized by comprising a recording medium having a light-collecting structure for emitting light, and a near-field optical head.

According to the present invention, since the recording medium has a condensing structure for condensing the irradiation light radiated from the outside to the data recording unit, the data recording unit is irradiated by the condensing effect of the condensing structure. The amount of light to be emitted increases, and stronger near-field light is generated in the data recording unit. The intensity of propagating light obtained by making the near-field light and the near-field optical head interact increases.

Further, a second optical information recording / reproducing apparatus according to the present invention is an optical information reproducing apparatus for recording / reproducing information by a near-field optical head using near-field light, wherein said optical information recording / reproducing apparatus comprises a light source and a lens. An irradiation optical system that emits light to generate near-field light, a medium substrate that is transparent to the wavelength of the irradiation light, and a data recording unit and a data recording unit on the medium substrate surface on which information to be recorded and reproduced is formed. A recording medium comprising a light-collecting structure for condensing the irradiation light, a near-field optical head for reproducing information from the recording medium, and a near-field optical head for recording information on the recording medium. It is characterized by having.

According to the present invention, not only reproduction of the information recorded on the recording medium but also recording of the information on the recording medium can be realized. Further, by matching the positional relationship between the minute opening used for reproducing information and the minute opening for recording used for recording information with the data recording section, the data recorded on the data recording section being reproduced is reproduced simultaneously with the reproduction of the data from the data recording section. The data can be recorded in a data recording unit different from the unit.

According to a third optical information recording / reproducing apparatus of the present invention, in the first or second optical information recording / reproducing apparatus, the light-collecting structure includes a tapered portion on which a reflective film is formed;
It is characterized by comprising a light-shielding portion for shielding the irradiation light in a region other than the data recording portion. According to the present invention, since the recording medium can be formed by transfer by forming the condensing structure in a tapered shape, mass production of the recording medium is possible, and the cost of the apparatus can be reduced.

A fourth optical information recording / reproducing apparatus according to the present invention is characterized in that, in the third optical information recording / reproducing apparatus, the reflection film also serves as a light shielding portion. According to the present invention, the reflection film formed on the tapered portion and the light-shielding portion become the same, and the number of steps for manufacturing the recording medium is reduced by one. Therefore, mass production and cost reduction of the recording medium can be realized.

A fifth optical information recording / reproducing apparatus according to the present invention is the first or second optical information recording / reproducing apparatus according to the first or second optical information recording / reproducing apparatus, wherein the data recording portions are formed on both sides of the medium substrate, and the condensing structure is a reflection film. Are formed on the tapered portion. According to the present invention, since a data recording portion can be formed on both sides of a recording medium, the capacity per recording medium can be doubled, and a large-capacity optical information recording / reproducing apparatus is provided. it can.

A sixth optical information recording / reproducing apparatus according to the present invention is the optical information recording / reproducing apparatus according to the third or fifth aspect, wherein the tapered portion on which the reflection film is formed has an inverted conical shape on which the reflection film is formed. Characterized in that it is a tapered portion.
According to the present invention, the shape of the tapered portion is an inverted weight shape,
Since the recording medium that can efficiently converge the irradiation light to the data recording section by the plurality of slopes of the tapered section where the reflective film is formed is used, the light source from the light source can be used more efficiently. It is not necessary to increase the output of the light source, and it is possible to suppress an increase in power consumption and heat generation due to an increase in the output of the light source.

In a seventh optical information recording / reproducing apparatus according to the present invention, in the third or fifth optical information recording / reproducing apparatus, the tapered portion on which the reflection film is formed has a V-shaped groove on which the reflection film is formed. Characterized in that it is a tapered portion.
According to the present invention, it is possible to perform tracking control using a data recording unit formed concentrically,
More stable signal reproduction can be performed.

[0027]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a recording medium and an optical information recording / reproducing apparatus according to the present invention will be described in detail with reference to the accompanying drawings. (Embodiment 1) FIG. 1 shows a configuration diagram of an optical information recording / reproducing apparatus according to Embodiment 1. In the optical information recording / reproducing apparatus shown in FIG.
A tapered opening 3 penetrating this is formed with a minute opening 4. The small aperture 4 has a diameter of, for example, several tens of nanometers so as to interact with near-field light 11 generated in the vicinity of the small aperture 4 and to extract the resulting propagation light 12.

The tapered opening 3 is formed by fine processing using, for example, photolithography or silicon anisotropic etching in a semiconductor manufacturing process. If the silicon substrate 2 does not have a sufficient light-shielding property with respect to the wavelength of the irradiation light 9, a light-shielding film such as a metal film such as Au / Cr is necessary. Can be

Irradiation light 9 radiated for reading data recorded on the recording medium 6 is obtained by an irradiation optical system composed of a light source 7 (for example, a semiconductor laser) and a collimating lens 8. FIG. 3 is a structural diagram of the recording medium according to the first embodiment, and FIG. 4 is a perspective view of the recording medium according to the first embodiment.

The recording medium 6 has an inverted quadrangular pyramid-shaped tapered portion 32 in which a reflection film is formed on a medium substrate 31 transparent to the wavelength of the irradiation light 9. A data recording section 33 is formed on the upper surface of the medium substrate 31, and a light-blocking section 34 that blocks the irradiation light 9 is formed in an area other than the data recording section 33. The reflection film of the tapered portion 32 is intended to focus light on the data recording portion 33. The light-shielding portion 34 is intended to prevent the irradiation light 9 and the condensed light beam 10 from being transmitted through the tapered portion 32 on which the reflection film is formed and from being irradiated on the data recording portion 33.
The size of the data recording section 33 is equal to or smaller than the light diffraction limit (for example, about 100 nm).

Here, the data recorded in each data recording section 33 need not be one bit, and a plurality of bits may be formed in one data recording section 33. Next, an example of a method for manufacturing the recording medium 6 will be described. FIG. 5 is a diagram illustrating a method for manufacturing a recording medium. This manufacturing method includes: (1) a convex shape forming step for forming a convex shape; (2) a transfer step for transferring the convex shape to a medium substrate; A reflection film / light-shielding part creating process for creating a part,
(4) A step of creating a data recording section on the surface of the medium substrate on which information to be recorded / reproduced is formed. (1) Protrusion Forming Step First, SiO ₂ 52 is formed on the upper surface of the Si substrate 51 by thermal oxidation or the like. Then, a photoresist 53 film is formed on the SiO ₂ 52 film, and the taper portion 32 of the recording medium 6 is formed.
A pattern of the photoresist 53 is created so as to leave only a portion corresponding to (FIG. 5A). Thereafter, isotropic etching is performed to create a conical convex shape 54 (FIG. 5).
b), unnecessary photoresist 53 is removed (FIG. 5)
c). (2) Transfer process The shape of FIG. 5-c is transferred to a medium substrate such as a plastic or glass substrate such as PMMA using FIG. 5-c as a mold (FIG. 5).
-D, Fig. 5-e). (3) Reflection film / light shielding portion forming step In order to form a reverse cone-shaped tapered portion 32 and a light shielding portion 34 in which a reflection film is formed on the medium substrate 31 on which the shape is transferred, a metal film such as Au or Cr is formed. A film is formed, and the metal film other than the data recording portion 33 is removed so that the metal film is formed only on the tapered portion 32 (FIG. 5F). (4) Data Recording Unit Creation Step Thereafter, a data recording layer for recording data marks of a size smaller than the wavelength or a data mark shape of a size smaller than the wavelength is formed on the data recording unit, thereby obtaining a recording medium 6.

Next, the optical information recording / reproducing apparatus shown in FIG.
A method of arranging the information on the recording medium 6 and reproducing information in the minute aperture 4 will be described. Here, the recording medium 6 is, for example, a disk-shaped flat substrate, and the near-field optical head 1 is disposed on the upper surface thereof. The disk-shaped recording medium is rotated at a high speed by a spindle motor (not shown) or the like. In order to allow the minute aperture 4 of the near-field optical head 1 and the near-field light 11 generated near the minute aperture 4 to interact with each other,
And the recording medium 6 need to be brought close to the diameter of the minute opening 4. Therefore, the near-field optical head 1 and the recording medium 6
Between the near-field optical head 1 and the recording medium 6 by utilizing the surface tension of the lubricant to fill the space between the near-field optical head 1 and the recording medium 6 by making the near-field optical head 1 sufficiently thin. it can. Furthermore, it can follow the bending of the recording medium 6. Further, the position of the near-field optical head 1 can be controlled by a not-shown near-field optical head control mechanism so that the minute opening 4 can be arranged at a desired position on the recording medium 6.

The proximity state between the near-field optical head 1 and the recording medium 6 may be controlled by an air bearing, similarly to the flying head used in hard disk technology, without using the above-mentioned lubricant. AFM control used for a near-field optical microscope may be performed. Recording medium 6
To reproduce the information recorded in the recording medium 6, first, the micro aperture 4 is moved to a desired information reproducing position on the recording medium 6 by the above-described control, and the data recording section 33 is formed by the light source 7 and the collimating lens 8. Irradiation light 9 from the surface opposite to the surface
Is irradiated on the recording medium 6. The light beam applied to the recording medium 6 is incident between the tapered portion 32 on which the reflective film is formed and the adjacent tapered portion. The irradiation light 9 becomes a condensed light beam 10 due to the light condensing effect of the two inclined surfaces of these tapered portions, and is irradiated on the data recording unit 33. And
Near-field light 11 is generated in a data recording portion of the recording medium 6 close to the minute opening 4 serving as a reproduction position. Due to such a light-collecting effect, the amount of light irradiated to the data recording unit 33 increases, and stronger near-field light is generated.

Due to the interaction between the near-field light 11 and the minute aperture 4, the propagating light 12 having characteristics such as intensity and phase depending on the recording state of the data recording part is transmitted through the minute aperture 4 to the tapered aperture. It is taken out above the part 3. Due to the increase in near-field light intensity due to the light condensing effect of the tapered portion 32, the light intensity of the extracted propagation light 12 also increases. The propagation light 12 is guided to the light receiving unit 5 and converted into an electric signal, and the recording state of the data recording unit is determined by a signal processing unit (not shown).

When the intensity of the light incident on the light receiving section 5 increases, a smaller data mark size can be reproduced, and a higher density memory can be realized. Alternatively, the S / N ratio can be improved by increasing the propagation light intensity, and higher-speed data reproduction can be performed. In the present embodiment, since the shape of the tapered portion 32 is an inverted quadrangular pyramid, the data recording portion 33 and the light shielding portion 34 are arranged like a checker pattern as shown in FIG. By making the shape of the tapered portion 32 into an inverted quadrangular pyramid shape, the irradiation light 9 can be efficiently condensed on the data recording portion 33 by the four slopes of the tapered portion 32 on which the reflection film is formed.

Further, since the near-field optical head 1 can be formed by a conventional semiconductor manufacturing process, it becomes easy to arrange a plurality of near-field optical heads 1 on the same silicon substrate. By creating such a multi-head, a plurality of data recorded in the data recording unit can be read out in parallel, and further high-speed data reproduction becomes possible.

FIG. 2 is a block diagram of another optical information recording / reproducing apparatus according to the first embodiment. In the configuration diagram of the optical information recording / reproducing apparatus according to the first embodiment in FIG. 1, the irradiation optical system is different. The other parts are exactly the same as the embodiment of FIG. The irradiation optical system according to the embodiment shown in FIG.
It comprises a light source 7 (for example, a semiconductor laser), a collimator lens 7 and a condenser lens 14. After the light beam from the light source 7 is converted into a parallel light beam by the collimator lens 8, the light beam is irradiated by the condenser lens 13 as the irradiation light 9 to read out the data recorded on the recording medium 6. At this time, since the light flux is converged toward the data recording unit 33, the light intensity applied to the data recording unit 33 is increased as compared with the case of irradiating the parallel light flux as shown in FIG. Further, since the angle of incidence of the irradiation light on the slope of the tapered portion 32 is smaller than that of the slope of the tapered portion 32, the light condensing effect of the slope of the tapered portion 32 on which the reflective film is formed increases.

Therefore, as compared with the embodiment shown in FIG. 1, the intensity of light incident on the light receiving section 5 is further increased, a smaller data mark size can be reproduced, and a higher density memory can be realized. be able to. Alternatively, by further increasing the propagation light intensity, the S / N ratio can be further improved, and higher-speed data reproduction becomes possible. Here, Figure 1
In the embodiment shown in FIG. 2 and FIG. 2, when the reflection film formed on the tapered portion 32 has a sufficient light-shielding property with respect to irradiation light, the light-shielding portion 34 can be omitted.

In this embodiment, the data recording unit 33
The size of the data recording unit 33 is not limited to this size, but may be as large as several μm, if the size of the data recording portion 33 is equal to or less than the diffraction limit of light (for example, about 100 nm). Therefore, a tapered shape has been described as the light-collecting structure. However, in the case where the size of the data recording unit is as large as several μm, if the light-collecting structure has a light-collecting function, a lens or the like may be used in addition to the tapered shape. However, the same effect can be obtained.

Further, in this embodiment, the case where the near-field optical head has a tapered opening having a minute opening has been described. However, any structure can be used as long as the near-field optical head can obtain the propagation light by interacting with the near-field light. A structure in which the light receiving element is located above the minute opening having no tapered opening, or a combination of the minute projection and the light receiving element may be used.
As described above, according to the first embodiment, in an optical information reproducing apparatus that records and reproduces information with a near-field optical head using near-field light, a medium substrate and a medium that are transparent to the wavelength of irradiation light Use a recording medium consisting of a data recording section for recording information on the substrate surface and an inverted cone-shaped tapered section on which a reflective film, which is a condensing structure for condensing irradiation light on the data recording section, is formed. Accordingly, the intensity of light incident on the light receiving unit can be increased, and higher-density memory and higher-speed data reproduction can be performed. Further, since the luminous flux from the light source can be used more efficiently, it is not necessary to increase the output of the light source, and it is possible to suppress an increase in power consumption and heat generation due to an increase in the output of the light source. This facilitates miniaturization and low power consumption of the device.

Further, since the recording medium can be prepared by transfer, mass production of the recording medium is possible and cost reduction is easy. Further, since the near-field optical head can be formed by using a semiconductor manufacturing process, it is suitable for mass production, can correspond to an array of near-field optical heads, and can perform ultra-high-speed data reproduction. (Embodiment 2) FIG. 6 is a perspective view of a recording medium showing another structure of the recording medium in Embodiment 1 of FIG. 1 or FIG. Note that the same reference numerals are given to parts common to the first embodiment, and description of the same parts as in the first embodiment is omitted or partially simplified.

FIG. 6 is a perspective view of a recording medium according to the second embodiment. The structural diagram showing the end face of the recording medium is exactly the same as that in FIG. The difference in structure from the recording medium in the first embodiment is that a v-groove-shaped taper portion 62 having one longer length is used instead of the inverted conical taper portion having a reflective film formed thereon.
The point is that. The width of the data recording section 33 is equal to or less than the diffraction limit of light (for example, about 100 nm).

Therefore, as in the case of the first embodiment, the recording medium 6 has a medium substrate 61 transparent to the wavelength of the irradiation light.
Is formed with a tapered portion 62 of a v-groove in which a reflection film is formed. A data recording section 63 is formed on the upper surface of the medium substrate 61, and a light-blocking section 64 that blocks the irradiation light 9 is formed in an area other than the data recording section 33. Also,
A plurality of bits of data are recorded in the data recording unit 63 in which one direction is long.

Next, an example of a method for manufacturing the recording medium 6 will be described. The recording medium shown in FIG. 6 can be produced by using the method for producing the recording medium 6 described in the first embodiment.
Here, another manufacturing method will be described. This manufacturing method includes: (1) a concave shape forming step of forming a concave shape;
(2) a reflective film for forming a reflective film and a light shielding portion in a concave shape;
The method comprises the steps of creating a light-shielding portion and (3) creating a data recording portion on the surface of the medium substrate on which information to be recorded / reproduced is formed. (1) Concave Shape Forming Step FIG. 7 is a diagram illustrating a method for manufacturing a recording medium according to the second embodiment. A V-groove-shaped tapered portion 62 is cut into a concave shape by a super-precision cutting technique used for forming a grating or the like on a parallel-substrate-shaped medium substrate 61 (FIG. 7-a) such as a plastic such as PMMA or a glass substrate. (FIG. 7B). (2) Reflection film / light shielding portion forming step In order to form a light shielding portion 64 and a V-groove taper portion 62 in which a reflection film is formed on a medium substrate 61 in which the shape of the taper portion 62 has been cut, such as Au or Cr. Then, the metal film other than the data recording portion 63 is removed so that the metal film is formed only on the tapered portion 62 (FIG. 7C). (3) Data Recording Unit Creation Step After that, a data recording layer for recording data marks of a size smaller than the wavelength or a data mark shape of a size smaller than the wavelength is formed on the data recording unit, and the recording medium 6 is obtained.

Next, a method of arranging the above-described recording medium shown in FIG. 6 in the optical information recording / reproducing apparatus shown in FIG. Of course, the optical information recording / reproducing apparatus shown in FIG. 2 can also be used. The recording medium 6 is, for example, a disk-shaped flat substrate, and the near-field optical memory head 1 is disposed on the upper surface thereof. The recording medium 6, which is a disc-shaped flat substrate, has a V-groove-shaped tapered portion 62 as shown in FIG. 6, and is like a CD or an analog record in the direction of rotation of the disc-shaped substrate. The V-groove tapered portion 62 is formed, and the data recording portion 63 is formed concentrically about the rotation axis of the recording medium 6. The method of reproducing information using such a recording medium 6 is exactly the same as that of the first embodiment, and a description thereof will be omitted.

As a tracking signal detecting method for accurately tracking the near-field optical head 1 on the data recording section,
There are a three spot type, a wobbling type and the like. Here, a wobbling type tracking signal detection method will be described. The near-field optical head 1 having the minute aperture 4 is slightly swung with respect to the recording medium 6 on which the concentric data recording section 63 is formed, and when the minute aperture 4 passes through the data pit on the data recording section. A tracking signal can be obtained by taking the difference between the signals from the obtained data pits. In this way, it is also possible to perform tracking control using the data recording unit 63 and the light shielding unit 64 formed concentrically.

As in the first embodiment, the width of the data recording section 33 is set to be equal to or smaller than the diffraction limit of light (for example, about 100 nm) in the present embodiment.
The size of is not limited to this size, several μ
It may be a large size such as m. Therefore, the tapered shape has been described as the light-collecting structure. However, when the size of the data recording unit is as large as several μm,
As long as the light-collecting structure has a light-collecting function, similar effects can be obtained by using a lens or the like in addition to the tapered shape.

Further, in this embodiment, the case where the near-field optical head has a tapered opening having a minute opening has been described. However, any structure can be used as long as it can obtain propagation light by interacting with near-field light. A structure in which the light receiving element is located above the minute opening having no tapered opening, or a combination of the minute projection and the light receiving element may be used.
In the present embodiment, when the reflection film formed on the tapered portion 62 has a sufficient light-shielding property with respect to irradiation light, the light-shielding portion 64 can be omitted.

As described above, according to the second embodiment, in an optical information reproducing apparatus for recording and reproducing information with a near-field optical head using near-field light, a medium transparent to the wavelength of irradiation light A recording medium comprising a substrate and a data recording section for recording information on the medium substrate surface, and a V-groove-shaped tapered section on which a reflective film as a light-collecting structure for condensing irradiation light on the data recording section is formed. Is used, the intensity of light incident on the light receiving unit can be increased.

Therefore, as in the first embodiment, a higher-density memory and higher-speed data reproduction can be realized. Furthermore, to be able to use the luminous flux from the light source more efficiently,
It is not necessary to increase the output of the light source, and it is possible to suppress an increase in power consumption and heat generation due to an increase in the output of the light source. This facilitates miniaturization and low power consumption of the device. Further, since the near-field optical head can be formed by using a semiconductor manufacturing process, it is suitable for mass production, can correspond to an array of near-field optical heads, and can perform ultra-high-speed data reproduction.

Further, in addition to the effect of the first embodiment, it is possible to perform tracking control using the data recording unit 63 and the light shielding unit 64 formed concentrically, so that more stable signal reproduction can be performed. . (Embodiment 3) FIG. 8 shows a configuration diagram of an optical information recording / reproducing apparatus according to Embodiment 3. Embodiment 1
The same reference numerals are given to portions common to the first and second embodiments, and description of the same portions as the first and second embodiments is omitted or partially simplified.

In the optical information recording / reproducing apparatus shown in FIG. 8, a near-field optical head 81 has a tapered opening 3 and a recording tapered opening 83 penetrating through a silicon substrate 82 with a minute opening 4 and a minute recording opening 84. Each is formed to have. The minute opening 4 is used for reading out information recorded on the recording medium 6, and the recording minute opening 84 is used for recording information on the recording medium 6.

The minute aperture 4 for reproducing information recorded on the recording medium 6 interacts with the near-field light 1 generated in the vicinity of the minute aperture 4 and can take out the propagation light 12 obtained as a result. Thus, for example, it has a diameter of several tens of nanometers. Irradiation light 9 emitted for reading data recorded on the recording medium 6 is obtained by an irradiation optical system including a light source 7 (for example, a semiconductor laser) and a collimating lens 8.

The recording light source 85 includes a recording lens 86.
Irradiates the recording taper opening 83 with light. Then, the minute aperture 84 for recording information on the recording medium 6 is formed such that near-field light is generated near the recording minute aperture 84.
For example, it has a diameter of several tens of nanometers. The near-field light in the vicinity of the recording minute opening 84 becomes writing light for recording information on the recording medium 6 by performing a writing operation.

The tapered opening 3 and the recording tapered opening 83 are formed by fine processing using, for example, photolithography or silicon anisotropic etching in a semiconductor manufacturing process. Also, the silicon substrate 82
However, if the film does not have a sufficient light-shielding property with respect to the irradiation light 9 and the wavelength of the recording light source 85, a light-shielding film such as a metal film of Au / Cr or the like is necessary. Can be

As the structure of the recording medium, the recording medium 6 used in the first embodiment shown in FIG. 4 and the recording medium 6 used in the second embodiment shown in FIG. 6 can be used. Here, in order to record information, the data recording unit 64 needs to have a data recording layer on which information can be recorded. Here, an embodiment using the recording medium 6 of FIG. 6 will be described.

In the optical information recording / reproducing apparatus shown in FIG. 8, a method for arranging a visual field optical memory head 81 on the recording medium 6 shown in FIG.
Since this is exactly the same as the case described above, the description is omitted. next,
A method of arranging the field optical memory head 81 on the recording medium 6 and recording information in the recording minute opening 84 will be described.

As in the case of reproducing information, the disc-shaped recording medium is rotated at a high speed by a spindle motor (not shown) or the like. Then, in order to cause the near-field light generated near the recording minute opening 84 of the near-field optical head 81 to interact with the recording medium 6, the recording minute opening is formed between the recording minute opening 84 and the recording medium 6. It is necessary to make them close to each other to the diameter of the opening 84. Then, the distance between the near-field optical head 81 and the recording medium 6 is kept sufficiently small by the same method as that for reproducing information from the recording medium 6. The position of the near-field optical head 81 is controlled by a not-shown near-field optical head control mechanism so that the recording minute opening 84 can be arranged at a desired position on the recording medium 6.

To record information on the recording medium 6, first,
With the above control, the minute opening 84 is moved to a desired information recording position on the data recording section 63 of the recording medium 6. Then, the recording taper opening 83 is irradiated with light by using the recording light source 85 and the recording lens 86. Then, near-field light is generated in the vicinity of the recording minute opening 84, and by performing a writing operation, information can be recorded at a desired position by an interaction between the near-field and the recording medium 6.

Further, by making the positional relationship between the minute opening 4 used for reproducing information and the recording minute opening 84 used for recording information coincide with the data recording section, reproduction of data from the data recording section is simultaneously performed. The data can be recorded in a data recording unit different from the data recording unit that performs the recording. Here, in the present embodiment, recording and reproduction of information are performed by one.
Although it is realized as two near-field optical heads, it can be divided into a near-field optical head for reproduction and a near-field optical head for recording. In such a case, recording and reproduction of information can be performed simultaneously and independently.

As described above, similar to the second embodiment, in an optical information reproducing apparatus for recording and reproducing information with a near-field optical head using near-field light, a medium transparent to the wavelength of irradiation light is used. A recording medium comprising a substrate and a data recording section for recording information on the medium substrate surface, and a V-groove-shaped tapered section on which a reflective film as a light-collecting structure for condensing irradiation light on the data recording section is formed. Is used, the intensity of light incident on the light receiving unit can be increased.

Further, according to the present embodiment, not only the information reproduction in the first and second embodiments, but also
Information can be recorded at the same time. (Embodiment 4) FIG. 9 shows a structural diagram of a recording medium used in an optical information recording / reproducing apparatus according to Embodiment 4. The recording medium of the present embodiment can also be used as the recording medium 6 of the embodiment of FIGS. 1, 2, and 3.

The recording medium 6 shown in FIG. 9 is different from the recording medium according to the first embodiment (FIGS. 3 and 4) or the recording medium according to the second embodiment (FIG. 6) in that the data recording sections are provided on both sides of the recording medium. This is an embodiment in the case of arrangement. A taper portion 92 having a reflection film formed on a medium substrate 91 transparent to the wavelength of irradiation light for reproducing information and recording light for recording information is formed through the medium substrate 91. This reflective film has a sufficient light-shielding property with respect to the wavelength of irradiation light for reproducing information and the wavelength of recording light for recording information. Then, the medium substrate 9
An upper data recording section 93 is formed on an upper surface of the recording medium 1, and a lower data recording section 94 is formed on a lower surface of the medium substrate 91. The width of each of the upper data recording section 93 and the lower data recording section 94 is smaller than the wavelength of the light to be used, for example, about several tens nm.

As described above, when the width of the upper data recording section 93 and the lower data recording section 94 is set to be equal to or less than the wavelength of the light to be used, when the irradiation light is irradiated from below the medium substrate 91, the lower data recording section The light irradiated between the lower data recording portion 94 and the adjacent lower data recording portion is irradiated to the upper data recording portion 93 by the light condensing effect of the tapered portion 92, and generates near-field light near the upper data recording portion.

On the other hand, when the lower data recording unit 94 is irradiated with irradiation light from below, the lower data recording unit 9
Since the size of 4 is smaller than the wavelength, for example, about several tens of nm, it exceeds the diffraction limit of light, so that the light cannot pass through the lower data recording unit 94 and propagate to the upper surface of the medium substrate 91. . Therefore, when the irradiation light is irradiated from below the medium substrate 91, near-field light is generated near the upper data recording unit 93 on the upper surface of the medium substrate 91, and other near-field light and propagating light transmitted through the medium substrate 91 are generated. There is no.

Similarly, when the irradiation light is incident from the upper side of the medium substrate 91, the near-field light is generated only near the lower data recording section 94. Therefore, the information recorded on the recording medium can be reproduced by receiving the propagating light generated by the interaction between the near-field light generated on the recording medium surface and the minute aperture of the near-field optical head by the light receiving element. It becomes possible. Therefore, the information recording surface is double-sided, and the recording capacity per recording medium is doubled.

In the embodiment shown in FIGS. 1, 2 and 5,
By arranging the near-field optical head and the irradiation optical system described above on both sides of the recording medium, both sides can be reproduced or recorded simultaneously. As described above, in the same manner as in the first, second, and third embodiments, in the optical information reproducing apparatus that records and reproduces information with the near-field optical head using the near-field light, From a medium substrate that is transparent to the wavelength, a data recording unit that records information on the surface of the medium substrate, and a taper unit on which a reflective film, which is a condensing structure for condensing irradiation light on the data recording unit, is formed. By using such a recording medium, the intensity of light incident on the light receiving unit can be increased. As described in the third embodiment, not only information reproduction but also information recording can be performed at the same time.

Furthermore, since data recording portions can be formed on both sides of the recording medium, the capacity per recording medium can be doubled.

[0069]

As described above, according to the first recording medium of the present invention, since the recording medium has a light-collecting structure for converging the light irradiated from the outside to the data recording section, Due to the light condensing effect of the light condensing structure, the amount of light applied to the data recording part increases, and stronger near-field light is generated in the data recording part. This near-field light and the near-field optical head are made to interact with each other. The intensity of the propagated light is increased.

Therefore, a smaller data mark can be reproduced, and a higher-density memory can be realized. Alternatively, the S / N ratio can be improved by increasing the propagation light intensity, and higher-speed data reproduction can be performed. further,
Since the luminous flux from the light source can be used more efficiently, it is not necessary to increase the output of the light source, and it is possible to increase power consumption and suppress heat generation by increasing the output of the light source, thereby reducing the size and power consumption of the device. Becomes easier.

According to the second recording medium of the present invention, in addition to the effect of the first recording medium, the recording medium can be formed by transfer by forming the condensing structure into a tapered shape. In addition, mass production of recording media is possible, and cost reduction is easy. According to the third recording medium of the present invention, in addition to the effects of the first or second recording medium, the reflection film formed on the tapered portion has the same shape as the light-shielding portion, and the process of manufacturing the recording medium Is reduced by one step, so that the cost can be further reduced.

Further, according to the fourth recording medium of the present invention, in addition to the effect of the first recording medium, data recording portions can be formed on both sides of the recording medium. Can be doubled. Even if the capacity per recording medium doubles, the production cost of the recording medium does not increase extremely, so that the price per unit recording capacity of the recording medium can be reduced.

According to the fifth recording medium of the present invention, in addition to the effects of the second or fourth recording medium,
Since the tapered portion has an inverted quadrangular pyramid shape, the irradiation light can be efficiently condensed on the data recording portion by the four slopes of the tapered portion on which the reflection film is formed. Therefore, to be able to use the luminous flux from the light source more efficiently,
It is not necessary to increase the output of the light source, and it is possible to suppress an increase in power consumption and heat generation due to an increase in the output of the light source, and it is easy to reduce the size and power consumption of the device.

According to the sixth recording medium of the present invention, in addition to the effects of the second or fourth recording medium,
Tracking control using a concentric data recording unit can be performed, and more stable signal reproduction can be performed. Further, according to the first method of manufacturing a recording medium according to the present invention, a medium substrate having a tapered shape can be formed by transfer, so that once a mold is formed, the transfer is performed by transfer. The medium can be mass-produced and the cost can be easily reduced.

Also, a mold required for transfer can be formed by a silicon process, and a data pit having a size smaller than the wavelength can be formed. Further, according to the method of manufacturing the second recording medium according to the present invention, in addition to the effect of the method of manufacturing the first recording medium according to the present invention, it is possible to further eliminate the step of forming a mold. Cost reduction is possible.

Further, according to the first optical information recording / reproducing apparatus of the present invention, since the recording medium has the light condensing structure for condensing the irradiation light radiated from the outside to the data recording section, the light condensing structure is used. Due to the condensing effect of the structure, the amount of light irradiated to the data recording unit increases, and stronger near-field light is generated in the data recording unit. The intensity of propagating light obtained by making the near-field light and the near-field optical head interact increases.

Therefore, a smaller data mark can be reproduced, and a higher-density memory can be realized. Alternatively, the S / N ratio can be improved by increasing the propagation light intensity, and higher-speed data reproduction can be performed. Furthermore, to be able to use the luminous flux from the light source more efficiently,
It is not necessary to increase the output of the light source, and it is possible to suppress an increase in power consumption and heat generation due to an increase in the output of the light source, and it is easy to reduce the size and power consumption of the device.

In addition, since the near-field optical head can be formed by a conventional semiconductor manufacturing process, it can be mass-produced and the cost can be easily reduced. In addition, it is easy to create a multi-head in which a plurality of near-field optical heads are arranged on the same silicon substrate, and it is possible to read out a plurality of data recorded in the data recording section in parallel, further improving high-speed data reproduction. It becomes possible.

According to the second optical information recording / reproducing apparatus according to the present invention, in addition to the effect of the first optical information recording / reproducing apparatus, not only the information recorded on the recording medium but also the recording medium can be reproduced. Can be recorded. Further, by matching the positional relationship between the minute opening used for reproducing information and the minute opening for recording used for recording information with the data recording section, the data recorded on the data recording section being reproduced is reproduced simultaneously with the reproduction of the data from the data recording section. The data can be recorded in a data recording unit different from the unit.

When a near-field optical head for recording and reproduction is used independently, recording and reproduction of information on a recording medium can be performed simultaneously and independently. Can be. According to the third optical information recording / reproducing apparatus according to the present invention, in addition to the effect of the first or second optical information recording / reproducing apparatus, the recording medium can be transferred by the tapered converging structure. Since it can be created, mass production of recording media is possible, and the cost of the apparatus can be reduced.

According to the fourth optical information recording / reproducing apparatus of the present invention, in addition to the effect of the third optical information recording / reproducing apparatus, the reflection film formed on the tapered portion and the light shielding portion become the same, Since the number of steps for manufacturing the medium is reduced by one, mass production and cost reduction of the recording medium can be realized, and the cost of the apparatus can be further reduced. Further, according to the fifth optical information recording / reproducing apparatus according to the present invention, in addition to the effects of the first or second optical information recording / reproducing apparatus, the data recording portions can be formed on both sides of the recording medium. The capacity per recording medium can be doubled.
Even if the capacity per recording medium doubles, the production cost of the recording medium does not increase extremely, so that the price per unit recording capacity of the recording medium can be reduced.

According to the sixth recording medium of the present invention, in addition to the effects of the third or fifth optical information recording / reproducing apparatus, the tapered portion has an inverted quadrangular pyramid shape, and the reflection film is formed. Since the recording medium that can efficiently converge the irradiation light on the data recording portion by the four inclined surfaces of the tapered portion is used, the output of the light source is increased because the light flux from the light source can be used more efficiently. No need,
It is possible to suppress an increase in power consumption and heat generation due to a large output of the light source, and it is easy to reduce the size and power consumption of the device.

Further, according to the seventh recording medium of the present invention, in addition to the effect of the third or fifth optical information recording / reproducing apparatus, a concentric data recording section is used. Tracking control can be performed, and more stable signal reproduction can be performed.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing an optical information recording / reproducing apparatus according to Embodiment 1 of the present invention.

FIG. 2 is a configuration diagram showing another optical information recording / reproducing apparatus according to Embodiment 1 of the present invention.

FIG. 3 is a structural diagram showing a recording medium according to Embodiment 1 of the present invention.

FIG. 4 is a perspective view showing a recording medium according to the first embodiment of the present invention.

FIG. 5 is a diagram showing a method for manufacturing a recording medium according to the first embodiment of the present invention.

FIG. 6 is a perspective view showing a recording medium according to a second embodiment of the present invention.

FIG. 7 is a diagram showing a method for manufacturing a recording medium according to Embodiment 2 of the present invention.

FIG. 8 is a configuration diagram showing an optical information recording / reproducing device according to a third embodiment of the present invention.

FIG. 9 is a structural diagram showing a recording medium according to a third embodiment of the present invention.

DESCRIPTION OF SYMBOLS 1, 81 Near-field optical head 2, 82 Silicon substrate 3 Tapered opening 4 Micro aperture 5 Light receiving element 6 Recording medium 7 Light source 8 Collimating lens 9, 14 Irradiation light 10, 15 Condensed light flux 11 Near-field light 12 propagated light 13 condenser lens 31,61,91 medium substrate 32,62,92 tapered portion 33,63 data recording unit 34, 64 light shielding portion 51 Si substrate 52 SiO ₂ layer 53 photoresist 54 convex 83 recording tapered opening 84 Micro aperture for recording 85 Light source for recording 86 Lens for recording 93 Upper data recording unit 94 Lower data recording unit

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Yasuyuki Mitsuoka 1-8-1, Nakase, Mihama-ku, Chiba City, Chiba Prefecture Inside of Iko Instruments Inc. (72) Inventor Hidetaka Maeda 1-8-8, Nakase, Mihama-ku, Chiba City, Chiba Prefecture Inside Iko Instruments Co., Ltd. (72) Inventor Kenji Kato 1-8-1, Nakase, Mihama-ku, Chiba City, Chiba Prefecture Inside Inko Instruments Co., Ltd. (72) Takashi Shinawa 1-8-1, Nakase, Nakase, Mihama-ku, Chiba Prefecture, Sico Instruments Co., Ltd. F term (reference) 5D029 JB32 JB50 KC01 MA14 MA50 5D119 AA43 CA20 JA43

Claims (15)

[Claims] 1. A recording medium for recording and reproducing information by a near-field optical head using near-field light, comprising: a medium substrate transparent to a wavelength of irradiation light irradiated to generate the near-field light; A data recording unit on the medium substrate surface on which information to be recorded / reproduced is formed; and a light-collecting structure for condensing the irradiation light on the data recording unit. recoding media. 2. The light-collecting structure includes: a tapered portion having a reflection film having a tapered shape in a thickness direction of the medium substrate; and a light-shielding portion for shielding the irradiation light in a region excluding the data recording portion. 2. The recording medium according to claim 1, comprising: 3. The recording medium according to claim 1, wherein said reflection film also functions as said light shielding portion. 4. The data recording section is formed on both sides of the medium substrate, and the light-collecting structure is a taper section formed with a reflection film having a taper shape in a thickness direction of the medium substrate. The recording medium according to claim 1, wherein 5. The tapered portion on which the reflection film is formed,
The recording medium according to claim 2, wherein the recording medium is an inverted conical tapered portion on which a reflection film is formed. 6. The tapered portion on which the reflection film is formed,
5. The recording medium according to claim 2, wherein the recording medium is a V-groove tapered portion on which a reflection film is formed. 7. A recording medium for recording / reproducing information with a near-field optical head using near-field light, a convex-shape creating step of creating a convex shape, a transfer step of transferring the convex shape to a medium substrate, A reflecting film / shading portion forming step of forming a reflecting film and a shading portion in a concave shape formed by the transfer step; and a data recording portion forming step on the medium substrate surface on which information to be recorded / reproduced is formed. A method for manufacturing a recording medium, comprising: 8. A recording medium for recording and reproducing information by a near-field optical head using near-field light, a concave-shape forming step of forming a concave shape, and a reflection of forming a reflective film and a light-shielding portion in the concave shape. A method for manufacturing a recording medium, comprising: a film / light-shielding portion forming step; and a data recording portion forming step on the surface of the medium substrate on which information to be recorded / reproduced is formed. 9. An optical information reproducing apparatus for reproducing information by a near-field optical head using near-field light, comprising: an irradiation optical system configured to emit the near-field light including a light source and a lens; A data recording portion on the surface of the medium substrate on which information to be recorded / reproduced is formed with a medium substrate transparent to the wavelength of the irradiation light; and a light condensing structure for condensing the irradiation light on the data recording portion. And an at least one near-field optical head for reproducing information from the recording medium. 10. An optical information reproducing apparatus for recording / reproducing information with a near-field optical head using near-field light, wherein an irradiation optical system configured to generate the near-field light includes a light source and a lens. And a data recording part on the surface of the medium substrate on which information to be recorded / reproduced is formed with a medium substrate transparent to the wavelength of the irradiation light, and a light condensing part for condensing the irradiation light on the data recording part. A recording medium having a structure; at least one near-field optical head for reproducing information from the recording medium; and at least one near-field optical head for recording information on the recording medium. An optical information recording / reproducing apparatus characterized by the above-mentioned. 11. The light-condensing structure includes a tapered portion on which a reflective film having a tapered shape in a thickness direction of the medium substrate is formed, and a light-shielding portion for shielding the irradiation light in a region other than the data recording portion. 11. The optical information recording / reproducing apparatus according to claim 9, wherein the optical information recording / reproducing apparatus comprises: 12. The optical information recording / reproducing apparatus according to claim 11, wherein said reflection film also functions as said light shielding portion. 13. The data recording part is formed on both sides of the medium substrate, and the light-collecting structure is a taper part formed with a reflection film having a taper shape in the thickness direction of the medium substrate. The optical information recording / reproducing apparatus according to claim 9 or 10, wherein 14. The optical information recording / reproducing apparatus according to claim 11, wherein the tapered portion on which the reflection film is formed is an inverted cone-shaped taper portion on which the reflection film is formed. 15. The optical information recording / reproducing apparatus according to claim 11, wherein the tapered portion on which the reflective film is formed is a V-shaped tapered portion on which a reflective film is formed.