JPH11353690A - Near-field optical memory head - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make an optical memory head a compact constitution and to be suited for a mass production and for being made to be an array in a near- field optical memory head reproducing information of a record medium by utilizing a near-field light. SOLUTION: In this optical memory head, a light source 1 including a wavelength component such as to transmit a flate substrate 9 is used and at least one inverse cone shaped tapered part is formed in the substrate 9 and a minute opening 12 is formed at its top part. Then, a light receiving element 10 is arranged at the upper part of the tapered part and the tapered part is given with a lightproof film 11 so that an irradiating light 7 from the light source 1 is not made directly incident on this light receiving element 10. By such a constitution, all of a near-field light generating system generating a near-field light on the surface of a record medium 5 and a near-field light detecting system guiding a propagation light 8 which is to be obtained by making the generated near-field light interact with the minute opening 12 to the light receiving element 10 and the element 10 are integrated into one body.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an optical memory head for reproducing high-density information by using near-field light.

[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.

[0003] Therefore, it is now possible to observe a minute area on the sample surface by using the propagation light and observing the interaction between the near-field light generated on the sample surface and the probe as an observation target. Near-field optical microscopes are receiving attention. 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] A near-field optical microscope often uses an optical fiber probe having a small opening at its tip by sharpening an optical fiber and coating the periphery with a metal. The optical fiber probe interacts with near-field light. The scattered light generated thereby is passed through the inside of the optical fiber probe and guided to the photodetector.

Further, by introducing light toward the sample through the optical fiber probe, near-field light is generated in a minute aperture of the optical fiber probe, and scattering caused by the interaction between the near-field light and the fine structure on the sample surface is caused. It is also possible to conduct the surface observation by guiding the light to the photodetector using the light-collecting system further added. Furthermore, by not only using it as a microscope, but also introducing relatively high-intensity light toward the sample through an optical fiber probe,
A near-field light having a high energy density is generated in a minute aperture of an optical fiber probe, and the near-field light can be used as a high-density optical memory recording that locally changes the structure or physical properties of the sample surface.

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. .

[0008]

However, the optical fiber probe, which has a sharpened tip, has insufficient mechanical strength and is not suitable for mass production and arraying. Further, since the scattered light obtained by disturbing the near-field light is very weak, when detecting the scattered light through an optical fiber, it is necessary to devise a method for obtaining a sufficient amount of light in the detection unit. In order to generate a sufficiently large near-field light through an optical fiber, it is necessary to devise a method of condensing the light at a minute opening of the optical fiber.

In the cantilever type optical probe, an optical fiber is inserted into the opening to receive scattered light from the optical waveguide layer or to introduce propagation light into the optical waveguide layer. A sufficient amount of light cannot be propagated between the optical fiber and the optical fiber without loss. It is difficult to realize an array of cantilever-type optical probes, particularly an array of two-dimensional arrays. Also, since these are originally intended for use as a microscope, information recording / reproduction of an optical memory is not in mind, and it is difficult to perform high-speed sweeping on a recording medium.

Further, when an optical fiber probe, a cantilever type optical probe and a plane probe are used as an optical memory head for reproducing information recorded on a recording medium, these probes generate near-field light on the recording medium. For near-field light generation, or is usually used only for one of the near-field light detection to scatter the generated near-field light and guide the scattered light to the photodetector, It has been difficult to realize information reproduction using only a probe.

In the case of the flat probe, since there is not enough space between the vicinity of the minute opening and the recording medium when the minute opening is close to the recording medium, the light is directed toward the surface of the recording medium. Irradiates the near-field light of the reflection type, which similarly produces near-field light on the surface of the recording medium. Accordingly, an object of the present invention is to provide a near-field optical memory head having a compact configuration and suitable for mass production and arraying in order to realize reproduction of information recorded in an optical memory using near-field light. .

[0012]

In order to achieve the above object, a near-field optical memory head for reproducing information on a recording medium using near-field light, comprising: at least one light source; A lens for irradiating the recording medium with the luminous flux of the above, a flat substrate having a minute opening formed by penetrating at least one inverted-cone-shaped hole so as to make the top a minute opening, A light-receiving element formed above the hole, and a light-shielding film for shielding light from the light source, wherein the at least one light source has a wavelength component that transmits at least the flat substrate, and Is shielded by the light shielding film, and the light receiving element receives the propagation light from the minute aperture.

Accordingly, the flat substrate transmits a part or all of the light beam from the light source, and irradiates the surface of the recording medium with the transmitted transmitted light component, thereby generating near-field light on the surface of the recording medium. Extraction of the propagated light generated by the interaction between the obtained near-field light and the minute aperture can be realized on the same substrate. A near-field optical memory head according to the present invention is a near-field optical memory head that reproduces information on a recording medium using near-field light, and records a light source including at least an infrared light component and a light flux from the light source. A lens for irradiating the medium, a flat substrate having a small opening formed by penetrating at least one inverted-cone-shaped hole so as to make the top part a small opening, and an upper part of the inverted-cone-shaped hole The formed light receiving element, and a light-shielding film for shielding the light beam from the light source, the flat substrate having the minute aperture, Si or GaAs capable of transmitting infrared light components
And the like, wherein the light emitted from the light source is shielded by the light shielding film, and the light receiving element receives the light propagated from the minute aperture.

Therefore, the flat substrate transmits the infrared light component,
By irradiating the surface of the recording medium with light by the transmitted infrared light component, near-field light is generated on the surface of the recording medium, and propagation light generated by the interaction between the generated near-field light and the minute aperture is extracted. It can be realized on the same substrate. Further, in the near-field optical memory head according to the present invention, the light-receiving element is formed on a plane substrate different from the plane substrate having the minute opening, and the light-receiving element is placed above the plane substrate having the minute opening. Are located.

Therefore, the process of forming the light receiving element on the substrate and the process of forming the minute aperture in the flat substrate are separated, and a near-field optical head can be easily realized by combining them. Further, in the near-field optical memory head according to the present invention, the light-receiving element may include at least one light-receiving element formed on a flat substrate, a conical projection formed on the light-receiving element, and the light-receiving element. A light-shielding film formed so as to surround the cone-shaped protrusion, wherein the light source has a wavelength component transmitting at least through the flat substrate and the cone-shaped protrusion, and the light-shielding film has a top portion of the cone-shaped protrusion. A fine opening is formed in the upper portion of the flat substrate, and the flat opening on which the fine opening is formed is arranged so that the fine opening faces the recording medium.

Therefore, the flat substrate transmits a part or all of the light beam from the light source, and irradiates the surface of the recording medium with the transmitted light so that near-field light is generated on the surface of the recording medium. Extraction of the propagation light generated by the interaction between the near-field light and the minute aperture can be realized on the same substrate. Further, in the near-field optical memory head according to the present invention, the light-receiving element may include at least one light-receiving element formed on a planar substrate, and a conical projection formed on the light-receiving element and transmitting infrared light. And a light-shielding film formed so as to surround the light-receiving element and the cone-shaped protrusion. A minute opening is formed in the light-shielding film above a top of the cone-shaped protrusion, and the minute opening is formed. In the flat substrate, the minute openings are arranged facing the recording medium.

Therefore, the flat substrate transmits the infrared light component,
By irradiating the surface of the recording medium with the transmitted infrared light, near-field light is generated on the surface of the recording medium, and the generated near-field light and the propagation light generated by the interaction between the minute aperture are extracted in the same manner. On a single substrate.
In addition, a near-field optical memory head can be formed on one flat substrate by a semiconductor process.

Further, in the near-field optical memory head according to the present invention, the lens is provided on a flat substrate having the minute opening.
A gradient index lens or a diffraction grating having a lens effect is integrated. Therefore, the near-field optical head including the lens can be easily reduced in size.

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the near-field optical memory head according to the present invention will be described below in detail with reference to the drawings. Embodiment 1 FIG. 1 is a sectional view of a near-field optical memory head according to Embodiment 1. FIG. 2 is a sectional view of only the near-field optical head unit 4 in FIG.

A light beam from a light source 1 containing an infrared light component is converted into a parallel light beam by a collimator lens 2 and is applied to a near-field optical head unit 4 using a lens 3. The silicon substrate has a very high transmittance with respect to the infrared light component, and the infrared light component from the light source 1 passes through the silicon substrate 9 and is irradiated onto the recording medium 5. Then, near-field light is generated on the surface of the recording medium 5.

In the near-field optical head 4 shown in FIG. 2, the silicon substrate 9 has a tapered opening 1 penetrating therethrough.
3 is formed with a minute opening 12. Small opening 1
Numeral 2 has a diameter of, for example, several tens of nanometers so as to interact with near-field light generated in the vicinity of the minute aperture 12 and extract the resulting propagated light 8. Further, the light receiving element 10 is mounted above the tapered opening 13. The irradiation light 6 from the light source 1 is applied to the surface of the tapered opening 13 and the light receiving element 10.
A light shielding film 11 is formed to optically block from 0.

The tapered opening 13 is formed by fine processing using, for example, photolithography or silicon anisotropic etching in a semiconductor manufacturing process. Further, the light source 1 includes an infrared light component that can pass through the silicon substrate 9. The light-shielding film 11 is a metal film such as Au / Cr, and is obtained by sputtering or vacuum deposition. The light-shielding film may be a thin-film multilayer film using interference as long as it can provide a sufficient light-shielding property for the wavelength component of the light source 1.

Next, the near-field optical head 4 described above is used.
Is arranged on the recording medium 5 and the information is reproduced at the minute aperture 12. Here, the recording medium 5 is, for example, a disk-shaped flat substrate, and the near-field optical head unit 4 is disposed on the upper surface thereof. In order to allow the minute aperture 12 of the near-field optical head 4 to interact with the near-field light generated on the surface of the recording medium 5, the gap between the minute aperture 12 and the recording medium 5 is brought close to the diameter of the minute aperture 12. There is a need. Therefore, a lubricant is filled between the near-field optical head unit 4 and the recording medium 5,
By making the near-field optical memory head sufficiently thin, the distance between the near-field optical head unit 4 and the recording medium 5 can be kept sufficiently small by utilizing the surface tension of the lubricant. Furthermore, it can follow the bending of the recording medium 5. Further, the minute aperture 12 is controlled by a near-field optical memory head control mechanism (not shown).
The position of the near-field optical head unit 4 can be controlled so that the near field optical head unit 4 can be arranged at a desired position on the recording medium 5.

The proximity state between the near-field optical head unit 4 and the recording medium 5 can be controlled by an air bearing without using the above-mentioned lubricant, similarly to the flying head used in the hard disk technology. Similar effects can be obtained by performing AFM control used in a field optical microscope. To reproduce information recorded on the recording medium, first, the minute opening 12 is moved to a desired information reproducing position on the recording medium 5 by the above-described control. Then, the infrared light component emitted from the light source 1 and transmitted through the silicon substrate 9 irradiates the information recording portion of the recording medium 5 close to the minute opening 12 serving as the reproduction position using the collimator lens 2 and the lens 3. Then, near-field light is generated in the information recording unit. The interaction between the near-field light and the minute opening 12 which is the tip of the tapered opening 13 provided with the light shielding film causes the propagation light 8 having characteristics such as intensity and phase depending on the recording state of the information recording section. Is a tapered opening 13 through a minute opening 12.
It is taken out upward. The extracted propagation light 8 is guided to the light receiving element 10 and converted into an electric signal, and the recording state of the information recording unit is determined by a signal processing unit (not shown). At this time, the light-shielding film 11 is configured so that light other than the propagation light 8 from the minute aperture 12 is not received by the light receiving element 10.

Further, since the near-field optical head 4 can be formed by a conventional semiconductor manufacturing process, it becomes easy to arrange a plurality of near-field optical heads 4 on the same silicon substrate. FIG. 6 shows a near-field optical memory head array. As the light source, a plurality of lasers or the like, such as a surface emitting laser, in which a plurality of light sources are formed on one chip can be used. Alternatively, a similar effect can be obtained even if a light beam is divided using one light source and a plurality of mirrors. Such a near-field optical memory head array is brought close to a recording medium on which information is recorded on a plurality of concentric tracks, and arranged so that the near-field optical memory head array is located on a plurality of tracks of the recording medium. By
It is possible to minimize the sweep of the head on the recording medium and perform high-speed optical recording or reproduction without requiring tracking control.

As described above, according to the first embodiment, on a recording medium on which information can be reproduced at a high density by using near-field light, the recorded information can be reproduced. To do so, a near-field light generation system that generates near-field light on the recording medium, and a near-field light detection system that guides propagation light obtained by interacting with the generated near-field light to a light receiving element are integrated. A near-field optical memory head is provided,
The configuration of the entire optical memory device is made compact, and adjustment of each component is unnecessary.

Further, since the near-field optical memory head according to the present invention can be formed by using a semiconductor manufacturing process, it is suitable for mass production, and can be adapted to an array of near-field optical memory heads. Further, in the present invention, a silicon substrate is used, but it goes without saying that the same effect can be obtained by using another semiconductor substrate such as GaAs.

[Second Embodiment] FIG. 3 is a sectional view of a near-field optical head in a near-field optical memory head according to a second embodiment. Note that parts common to those in FIG. 2 are denoted by the same reference numerals. The description of the same parts as in the first embodiment will be simplified or omitted. The near-field optical memory unit in FIG. 3 is completely replaced with the near-field optical head unit 4 according to the first embodiment in FIG. The near-field optical head unit shown in FIG. 3 includes two silicon substrates A14 and B16. FIG. 4 shows an exploded view of each silicon substrate.

In the silicon substrate A14 shown in FIG. 4A, a tapered opening 13 penetrating the silicon substrate A14 is formed to have a minute opening 12. The small aperture 12 has a diameter of, for example, several tens of nanometers so as to interact with near-field light generated on the surface of the recording medium 5 and extract the resulting propagation light 8. Further, a light-shielding film 15 is formed on the surface of the tapered opening 13 so as to optically block the irradiation light 6 from the light source 1.

The silicon substrate B16 shown in FIG. 4B is processed as much as the light-shielding film 18 and the light-receiving element 17 can be formed, the light-shielding film 18 is applied thereon, and finally the light-receiving element 17 is formed. I have. Then, the silicon substrate B16
Is turned upside down to overlap the silicon substrate A14. At this time, it is necessary to perform positioning or the like so that the light receiving element 17 can be optically closed by the light 6 emitted from the light source 1 by the light shielding film 15 and the light shielding film 18.

The tapered opening 13 is formed by fine processing using, for example, photolithography or silicon anisotropic etching in a semiconductor manufacturing process. The light source 1 includes a silicon substrate A14 and a silicon substrate B1.
6 includes an infrared light component that can be transmitted. The light-shielding film 15 and the light-shielding film 18 are metal films such as Au / Cr, for example, and are obtained by sputtering or vacuum deposition. As long as these light-shielding films can provide a sufficient light-shielding property with respect to the light component of the light source 1, a similar effect can be obtained by a thin film using interference or the like.

The method of arranging the near-field optical head described above on the recording medium 5 and reproducing information at the minute aperture 12 is exactly the same as that of the first embodiment, and a description thereof will be omitted. In the above-described second embodiment, the near-field optical memory unit can be formed by using a semiconductor manufacturing process and can be formed by bonding two silicon substrates.
It is suitable for mass production, can easily cope with arraying as described in Embodiment 1, and can be used as a near-field optical memory head array.

Although a silicon substrate is used in the present invention, it goes without saying that the same effect can be obtained by using another semiconductor substrate such as GaAs. Third Embodiment FIG. 5 is a sectional view of a near-field optical head in a near-field optical memory head according to a third embodiment. The description of the same parts as in the first and second embodiments is simplified or omitted.

The near-field optical head shown in FIG. 5 is completely replaced with the near-field optical head 4 according to the first embodiment shown in FIG. In the near-field optical head of FIG. 5, a lower light-shielding film 21 is formed on a silicon substrate 19, and a light receiving element 20 is formed on the lower light-shielding film 21. Thereafter, a conical projection 24 is formed on the light receiving element 20. Finally, an upper light-shielding film 22 is formed, and a minute opening 23 is formed in the upper light-shielding film 22 above the conical projection 24. Small aperture 23
Has a diameter similar to that of the first embodiment.

The near-field optical head portion, which is a flat substrate having such a minute opening formed thereon, has the minute opening 23 formed on the recording medium 5.
It is turned upside down so as to be on the side, thereby forming a near-field optical memory head. The lower light-shielding film 21 and the upper light-shielding film 22
Is a metal film such as Au / Cr, and is obtained by sputtering or vacuum deposition. As long as these light-shielding films can provide a sufficient light-shielding property with respect to the light component of the light source 1, a similar effect can be obtained by a thin film using interference or the like.
The pyramidal projection 24 is, for example, SiO ₂ and is formed by fine processing using photolithography or silicon anisotropic etching in a semiconductor manufacturing process.
The pyramidal projection 24 only needs to transmit the infrared light component.
Other materials that transmit infrared light components are also possible.

The method of arranging the near-field optical head described above on the recording medium 5 and reproducing information in the minute aperture 23 is exactly the same as that of the first embodiment, and therefore a part of the description is omitted or simplified. To To reproduce the information recorded on the recording medium, first, the minute opening 23 is moved to a desired information reproducing position on the recording medium 5. Then, the infrared light component emitted from the light source 1 and transmitted through the silicon substrate 9 irradiates the information recording portion of the recording medium 5 close to the minute opening 23 serving as the reproduction position, and near-field light is generated in the information recording portion. Generated. The pyramidal projection 24 to which the near-field light and the light-shielding film are attached
Interacts with the micro-aperture 23, which is the tip of the information recording portion, the propagating light 8 having characteristics such as intensity and phase depending on the recording state of the information recording portion is transmitted through the micro-aperture 23 to the conical projection 2
4 It is taken out upward. The extracted propagation light 8 is guided to the light receiving element 20 and converted into an electric signal, and the recording state of the information recording unit is determined by a signal processing unit (not shown). At this time, the upper light-shielding film 21 and the lower light-shielding film 22 are configured so that light other than the propagation light 8 from the minute opening 23 is not received by the light receiving element 20.

In the third embodiment described above, the near-field optical memory section can be formed by using a semiconductor manufacturing process, and one silicon substrate can be formed more. Therefore, it is suitable for mass production. Such an array can be easily coped with and can be used as a near-field optical memory head array. Further, in the present invention, a silicon substrate is used, but it goes without saying that the same effect can be obtained by using another semiconductor substrate such as GaAs.

Fourth Embodiment FIG. 7 is a sectional view of a near-field optical memory head according to a fourth embodiment. In the present embodiment, the lens 3 and the near-field optical head in Embodiment 2 are integrated, and the same reference numerals are given to common parts. The near-field optical memory head of FIG. 7 includes a silicon substrate A14 and a silicon substrate B16.
And a glass substrate 27. FIG. 8 is an exploded view of these substrates. In the fourth embodiment, a glass substrate 27 having a refractive index distribution lens 28 is superposed and integrated further on the silicon substrate A14 and the silicon substrate B16 of the second embodiment. ing. Glass substrate 27 having refractive index distribution lens 28
, The lens 3 of the second embodiment can be omitted.

The method of arranging the near-field optical memory head described above on the recording medium 5 and reproducing information in the minute aperture 12 is the same as that of the first embodiment, so that the description is partially omitted or simplified. . To reproduce information recorded on the recording medium, first, the minute opening 12 is moved to a desired information reproducing position on the recording medium 5. Since the glass substrate, the silicon substrate A14, and the silicon substrate B16 transmit the infrared light component, the infrared light component emitted from the light source 1 is located at the reproduction position by the refractive index distribution lens 28 formed on the glass substrate 27. The information recording portion of the recording medium 5 close to the minute opening 12 is irradiated. Then, near-field light is generated in the information recording unit. The interaction between the near-field light and the minute aperture 12 which is the tip of the tapered portion 13 provided with the light-shielding film 15 causes the propagation light 8 having characteristics such as intensity and phase depending on the recording state of the information recording portion. Is taken out above the tapered portion 13 through the minute opening 12. The extracted propagation light 8 is guided to the light receiving element 17 and converted into an electric signal, and the recording state of the information recording unit is determined by a signal processing unit (not shown). At this time, the light-shielding film 18 is configured so that light other than the propagation light 8 from the minute aperture 12 is not received by the light receiving element 17.

Since such a near-field optical memory head can be formed by using a semiconductor manufacturing process, it is suitable for mass production, and can cope with an array as described in the first and second embodiments. It can be used as a head array. As an example, FIG. 9 shows a near-field optical memory head array in which near-field optical memory heads according to the fourth embodiment are arranged in an array.

It is needless to say that the refractive index lens 28 may be a lens having a lens effect such as a diffraction grating. [Fifth Embodiment] FIG. 10 is a sectional view of a near-field optical memory head according to a fifth embodiment. In the present embodiment, the lens 3 and the near-field optical head unit 4 according to the first embodiment are integrated as in the fourth embodiment. I have.

In order to integrate the near-field optical head unit and the lens 3 described in the first embodiment, the near-field optical head unit 4 shown in FIG. The diffraction grating 29 was arranged. The diffraction grating 29 is designed so that the irradiation light 6 is irradiated near the minute aperture. Then, the irradiation light 6 is irradiated on the recording medium 5 by the diffraction grating 29, and near-field light is generated on the surface of the recording medium 5. Then, the light receiving element 10 receives the propagation light 8 due to the interaction between the near-field light and the minute aperture. Diffraction grating 2
9 is formed by fine processing using, for example, photolithography or silicon anisotropic etching in a semiconductor manufacturing process.

To reproduce the information recorded on the recording medium, first, the minute opening 12 is moved to a desired information reproducing position on the recording medium 5. Since the silicon substrate transmits the infrared light component, the infrared light component emitted from the light source 1 is diffracted by the diffraction grating 2 formed near the light receiving element 10 on which the light shielding film 11 is provided.
9 irradiates the information recording portion of the recording medium 5 that is close to the minute opening that is the reproduction position. Then, near-field light is generated in the information recording unit. This near-field light and the light shielding film 1
1 is a small opening 1 which is the tip of the tapered portion 13
2, the propagating light 8 having characteristics such as intensity and phase depending on the recording state of the information recording unit is guided to the light receiving element 10 through the minute aperture, and is converted into an electric signal. The recording state of the information recording unit is determined by a signal processing unit (not shown). At this time, the light-shielding film 11 is configured so that light other than the propagation light 8 from the minute aperture is not received by the light receiving element 10.

Further, since the near-field optical memory head described above can be formed by using a semiconductor manufacturing process including a diffraction grating, it is suitable for mass production, and can be formed into an array as described in the first and second embodiments. It can be used and can be used as a near-field optical memory head array. As an example, FIG. 11 shows a near-field optical memory head array in which near-field optical memory heads are arranged in an array.

As described above, according to the fifth embodiment, a near-field light generating system for generating a reflection type near-field light on a recording medium, and an image obtained by interacting with the generated near-field light. There is provided a near-field optical memory head in which a near-field light detection system for guiding propagation light to a light receiving element is integrated. Since the configuration is simple, a complicated manufacturing process is not required, the configuration of the entire optical memory device is made compact, and adjustment of each component is unnecessary.

[Embodiment 6] In Embodiment 1 of FIGS. 1 and 2, a glass substrate such as BK7 is used instead of the silicon substrate 9 as the plane substrate, and the glass substrate is sufficiently used as the light source 1. A light source including a wavelength component having high transmittance (for example, visible light) was used, and a light shielding film 11 was formed to optically block the irradiation light 6 from the light source 1 from the light receiving element 10. The small aperture 12 has a diameter of, for example, several tens of nanometers so as to interact with near-field light generated in the vicinity of the small aperture 12 and extract the resulting propagation light 8. Other parts are the first embodiment.
Is the same as

The tapered opening 13 is formed, for example, by mechanical fine processing or by heating and softening a glass substrate and transferring a previously prepared conical mold shape. Further, the light source 1 includes a visible light component that can pass through the glass substrate. The light-shielding film is a metal film such as Au / Cr as in the first embodiment, and is obtained by sputtering or vacuum deposition. The light-shielding film may be a thin-film multilayer film using interference as long as sufficient light-shielding properties can be obtained for the wavelength component of the light source 1.

The above-described method of arranging the near-field optical head on the recording medium 5 and reproducing the information in the minute aperture 12 is different from that of the first embodiment in that the wavelength component used for the light source is different and the material of the flat substrate is different. Since it is exactly the same as the first embodiment, the description is omitted. In the sixth embodiment described above,
As in the first embodiment, in a recording medium on which information can be reproduced at a high density and which can be reproduced by using near-field light, to reproduce the recorded information, a near-field A near-field optical memory head that integrates a near-field light generation system that generates light, and a near-field light detection system that guides propagation light obtained by interacting with the generated near-field light to a light receiving element is provided. The configuration of the entire apparatus is made compact, and adjustment of each component is unnecessary.

Further, since a light source having a wavelength component shorter than that of infrared light can be used as the wavelength,
The light intensity of the propagating light 8 from 2 increases, and the light intensity obtained on the light receiving element 10 increases. In addition, Embodiment 1
It can also support arraying as described in
It can be used as a near-field optical memory head array.

Also in the second to fifth embodiments, similarly to the sixth embodiment, a glass substrate such as BK7 is used as the flat substrate instead of the silicon substrate, and the light source 1 is sufficiently transparent to the glass substrate. The present invention can be applied to a case where a light source including a wavelength having a high rate (for example, visible light) is used, and similar effects can be obtained in each embodiment.

In the above description, a glass substrate was used as the flat substrate, but polymethyl methacrylate (PMM) was used.
Similar effects can be obtained by using a plastic such as A) or an optical crystal such as TiO ₂ . In other words, the wavelength band or the wavelength component of the light source only needs to include a wavelength component that transmits through the flat substrate, and a flat substrate having a sufficiently high transmittance for a certain wavelength and a light source including the wavelength component are used Thus, the present invention can be implemented with materials other than the above-described material of the flat substrate.

[0052]

As described above, according to the present invention, a near-field light generating system for generating near-field light on a recording medium and a propagating light obtained by interacting with the generated near-field light are provided. The near-field light detection system leading to the light receiving element, and further the light receiving element are integrated. For this reason, the configuration of the entire optical memory device is made compact, and adjustment of each component is unnecessary. Further, it is possible to easily realize an array of heads.

Further, since a near-field optical memory head can be manufactured without requiring a complicated manufacturing process, it can be manufactured using a semiconductor process, particularly when a silicon substrate is used as a flat substrate, and mass production can be performed at low cost. It is.

[Brief description of the drawings]

FIG. 1 is a sectional view of a near-field optical memory head according to a first embodiment of the present invention.

FIG. 2 is a sectional view of a near-field optical head according to the first embodiment of the present invention.

FIG. 3 is a sectional view of another near-field optical head according to a second embodiment of the present invention;

FIG. 4 is an exploded view of another near-field optical head according to the second embodiment of the present invention.

FIG. 5 is a sectional view of another near-field optical head according to Embodiment 3 of the present invention.

FIG. 6 is a diagram illustrating an array of near-field optical memory heads according to the first embodiment of the present invention.

FIG. 7 is a sectional view of a near-field optical memory head according to a fourth embodiment of the present invention.

FIG. 8 is an exploded view of a near-field optical memory head according to a fourth embodiment of the present invention.

FIG. 9 is a diagram illustrating an array of near-field optical memory heads according to a fifth embodiment of the present invention.

FIG. 10 is a sectional view of a near-field optical memory head according to a fifth embodiment of the present invention.

FIG. 11 is a diagram illustrating an array of near-field optical memory heads according to a fifth embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Light source 2 Collimator lens 3 Lens 4 Near field optical head part 5 Recording medium 6, 7 Irradiation light 8 Propagation light 9, 19, 25 Silicon substrate 10, 17, 20 Light receiving element 11, 15, 18 Light shielding film 12 Micro aperture 13 Tapered opening 14 Silicon substrate A 16 Silicon substrate B 21 Lower light-shielding film 22 Upper light-shielding film 23 Micro aperture 24 Conical projection 26 Near-field optical memory head 27 Glass substrate 28 Refractive index distribution lens 29 Diffraction grating

Continuation of the front page (51) Int.Cl. ⁶ Identification symbol FI G02B 7/00 G02B 7/00 H H01L 31/02 H01L 31/02 A (72) Inventor Tokuo Chiba 1-8 Nakase Nakase, Mihama-ku, Chiba-shi, Chiba Address Seiko Instruments Co., Ltd. (72) Inventor Kenji Kato 1-8-1, Nakase, Mihama-ku, Chiba City, Chiba Prefecture Inside Seiko Instruments Co., Ltd. (72) Takashi Shinawa, 1-8-1, Nakase, Mihama-ku, Chiba City, Chiba Prefecture Inside Seiko Instruments Inc. (72) Inventor Kunio Nakajima 1-8-1 Nakase, Mihama-ku, Chiba-shi, Chiba Seiko Instruments Inc.

Claims (10)

[Claims] 1. A near-field optical memory head for reproducing information from a recording medium using near-field light, comprising: at least one light source; a lens for irradiating a light beam from the light source to the recording medium; A flat substrate having a minute opening formed by penetrating at least one inverted-cone-shaped hole so as to make the top a minute opening; a light-receiving element formed above the inverted-cone-shaped hole; and the light source A light-shielding film for shielding light from the light source, the at least one light source includes a wavelength component that transmits through the flat substrate, and irradiates the light from the light source with the light-shielding film. A near-field optical memory head, wherein the light receiving element receives light propagated from the light receiving element. 2. A near-field optical memory head for reproducing information from a recording medium using near-field light, comprising: at least one light source including at least an infrared light component; and a light flux from the light source to the recording medium. A lens for irradiating, a flat substrate having a small opening formed by penetrating at least one inverted-cone-shaped hole so as to make the top a small opening, and a flat substrate formed on the inverted-cone-shaped hole A light-receiving element, and a light-shielding film for shielding light from the light source, wherein the flat substrate having the minute openings is a semiconductor substrate,
A near-field optical memory head, wherein irradiation light from the light source is shielded by the light-shielding film, and propagation light from the minute aperture is received by the light-receiving element. 3. The light-receiving element is a light-receiving element formed on a plane substrate different from the plane substrate having the minute opening, and is disposed on the plane substrate having the minute opening with the light-receiving element facing down. 3. The near-field optical memory head according to claim 1, wherein 4. A near-field optical memory head for reproducing information on a recording medium using near-field light, comprising: at least one light source; a lens for irradiating a light beam from the light source to the recording medium; At least one light receiving element formed on a planar substrate, a conical protrusion formed on the light receiving element, a light shielding film formed so as to surround the light receiving element and the conical protrusion, Wherein the light-shielding film has a minute opening at the top of the cone-shaped protrusion, and the at least one light source includes a wavelength component that passes through the flat substrate and the cone-shaped protrusion, and The near-field optical memory head according to claim 1, wherein the flat substrate on which the fine opening is formed has the fine opening disposed on the recording medium side. 5. A near-field optical memory head for reproducing information from a recording medium using near-field light, comprising: at least one light source including at least an infrared light component; and a light flux from the light source to the recording medium. A lens for irradiating, at least one light receiving element formed on a planar substrate, a conical projection formed on the light receiving element, which transmits infrared light, the light receiving element and the conical shape A light-shielding film formed so as to enclose the projection, wherein the light-shielding film has a minute opening above the top of the conical projection, and the flat substrate is a semiconductor substrate; The near-field optical memory head according to claim 1, wherein the minute opening is arranged on the recording medium side of the flat substrate having the opening. 6. The flat substrate having the micro opening or the micro opening, wherein the lens according to claim 1, 2, 4, or 5 is formed on a flat substrate and is disposed above the light receiving element. The near-field optical memory head according to any one of claims 1 to 5, wherein the flat substrate on which is formed, the light receiving element, and the lens are integrated. 7. The lens according to claim 1, wherein the lens according to claim 1, 2, 4, 5, or 6 is a gradient index lens formed on a flat substrate. Item 7. A near-field optical memory head according to any one of Items 6. 8. A lens according to claim 1, wherein the lens is a diffraction grating having a lens effect formed on a flat substrate. A near-field optical memory head according to any one of claims 1 to 6. 9. The lens according to claim 1, 2, 4, or 5, wherein the lens is a diffraction grating having a lens effect formed near the light receiving element. A near-field optical memory head according to any one of claims 1 to 5. 10. A near-field optical memory head, wherein a plurality of near-field optical memory heads according to claim 1 are arranged on the same plane.