JP3449210B2 - Optical recording method and optical recording system - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical recording method and an optical recording system, and more particularly to an optical recording method and an optical recording system using a distribution of near-field light generated by irradiation of an information object with light.

[0002]

2. Description of the Related Art Conventionally, as a method of optically recording on a recording medium, for example, recording light from a laser light source is condensed and applied to the recording medium to change the light reflectance of the recording medium for recording. Methods etc. are known.

However, an optical system utilizing not only laser light but also propagating light propagating gas or the like cannot be used essentially in a region below the diffraction limit of light, and thus recording on a scale below that limit. I can't achieve the density, and
It is also not possible to perform optical recording on objects of sizes below that limit.

Therefore, in recent years, so-called near-field light has attracted attention. Since near-field light is localized in a region smaller than the wavelength of light on the surface of a substance, high-density information recording and a high-resolution optical microscope using this have been proposed.

For example, "Research on Machinery Vol. 49, No. 5 (1
997) ”," The present state and future of development of near-field optical microscopes "by Motoichi Otsu in" The near-field optical microscope called C-mode as follows, and the following I
A near-field optical microscope called mode is introduced.

Evanescent light (near-field light) generated on the sample surface by light irradiation is picked up by scanning a fine probe to obtain a three-dimensional image of the sample surface through predetermined data processing.

When light is incident on the fine probe itself, near-field light is exuded from a terminal at its tip, and the near-field light is converted into scattered light by scanning the probe along the sample surface. Obtain information on the sample surface.

[0008]

However, in any of the above-mentioned techniques using near-field light, it takes a long time to scan the probe, the light intensity that can be detected by using the microprobe is small, and the probe Therefore, there was a problem that the electric field near the sample was greatly disturbed.

Further, it is known that when the sample or the like is a minute object of the order of nm to μm, the momentum of the photon changes due to the reflection and refraction of the irradiation light to cause the object to move. If such a phenomenon occurs, a correct sample image cannot be obtained. Similar defects can occur even if the sample is a microorganism that can move spontaneously.

Therefore, the present invention has as an object to solve the problem. When the inventor of the present application positions an information object (observation sample or object for information input) on the surface of the photosensitive material and irradiates the area with light, a photoreaction due to near-field light at a portion on the surface of the photosensitive material where the information object is located. Occurs more strongly than the photoreaction caused by irradiation light in other parts,
The present invention has been completed based on the new finding called

[0011]

(Structure of First Invention) The structure of the first invention of the present application (the invention according to claim 1) for solving the above-mentioned problems is an arbitrary photoreaction that can be stored and detected. The recording area surface is formed by using a photosensitive material capable of causing the, and an information object is positioned in contact with the recording area surface,
By irradiating light on at least an area where the information object is located on the recording area surface, the distribution of near-field light generated in the information object is recorded on the photosensitive material as a photoreactive amount of the photosensitive material. is there.

(Configuration of Second Invention) The configuration of the second invention of the present application (the invention according to claim 2) for solving the above-mentioned problems is as follows.
A recording area surface is formed by using a photosensitive material capable of causing an arbitrary photoreaction that can be stored and detected, and an information object that is a movable body is positioned in contact with the recording area surface, and The operation of irradiating at least the area where the information object is located and recording the distribution of the near-field light generated in the information object on the photosensitive material as the amount of photoreaction of the photosensitive material is performed according to the movement of the information object. This is an optical recording method that is repeated more than once.

(Configuration of Third Invention) The configuration of a third invention of the present application (an invention according to claim 3) for solving the above-mentioned problems is as follows.
A recording area surface for locating an information object in a contact state, which is composed of a photosensitive material capable of causing any photoreaction that can be stored and detected, and at least an area of the recording area surface where the information object is located. An optical recording system comprising a light source capable of simultaneously irradiating light.

[0014]

(Operation and effect of the invention) (Operation and effect of the first invention) In the first invention, when the area including the information object on the recording area surface is irradiated with light, the near-field light at the portion of the photosensitive material surface where the information object is located. The photoreaction caused by the light occurs more strongly than the photoreaction caused by the irradiation light in other parts. As a result, the distribution of near-field light generated in the information object is recorded as a photoreaction amount of the photosensitive material at a level different from that of the surrounding portion.

The reason why such a phenomenon appears may be related to, for example, the high refractive index of the information object as compared with the propagation medium of the irradiation light (air or the like).
Near-field light may have a property of causing a particularly strong photoreaction, and various estimations are possible, and at present, it is not definitively understood.

According to the first aspect of the invention, the probe for picking up only the near-field light of the information object as in the C mode of the prior art acts on the information field only as in the I mode of the prior art. No probe is required to do this. Therefore, the time for scanning the probe is not required, and the recording is completed by only irradiating the light once. Also, there are no other problems mentioned above due to the use of the probe.

Since the optical recording is completed by a single irradiation of light, when the information object is a minute object or a living thing (especially a microorganism), there is no recording failure due to the movement of the object or the time variation of the refractive index distribution. Furthermore, in order to irradiate the entire predetermined area with light, various information objects randomly arranged in the area can be simultaneously recorded, or a large number of information objects mutually arranged with a predetermined information meaning can be simultaneously recorded, All information of a large information object can be recorded at one time.

The optical recording obtained according to the first invention can be subjected to observation / detection immediately or at any time after storage, using any and advantageous observation / detection means corresponding to the type of photoreaction. it can.

Since the first invention is optical recording utilizing near-field light, it is possible to perform high-density optical information recording / high-resolution optical analysis / fine optical processing in a region below the diffraction limit of light.

(Operations and effects of the second invention) In the second invention, in addition to the effects of the first invention, fine particles that can move an information object by radiation pressure of light, microorganisms that move autonomously, etc. The fact that it is a movable body can be used as an advantage. That is, by repeating the light irradiation in response to the movement of the information object, not only the shape of the information object but also the movement thereof and the change of the shape or the property can be recorded as information.

For example, a phenomenon in which minute information objects are arranged along the electric field distribution of near-field light by receiving the radiation pressure of light is optically recorded, or by utilizing this phenomenon, the information objects move while controlling the movement. Can be optically recorded or optical processing can be performed at the moving part. Further, when the information object is accompanied by a change in property or form, it is possible to obtain an image of change over time. Furthermore, it is possible to trace the motility state of the microorganism, cell division or cell joining.

Further, by irradiating short pulse light in these cases, it is possible to continuously record a high-speed phenomenon and observe it slowly later.

(Operation and Effect of Third Invention) The optical recording system of the third invention can effectively implement the optical recording method of the first invention and / or the second invention. In this system, the probe and the drive / control / optical system related thereto are not required, so that the optical recording system is remarkably simplified and the cost is reduced.

[0024]

BEST MODE FOR CARRYING OUT THE INVENTION Next, embodiments of the first to third inventions will be described.

[Optical recording] In the first to third inventions,
"Optical recording" has a broader meaning than "information recording", which has a common sense. That is, not only in the case of recording in order to save the information from the information object that embodies the known information, but as in the near-field optical microscope, the information object itself is the analysis target and the information as the analysis data is recorded. This also includes the case of using an information object as processing information and processing means for fine processing, as in semiconductor lithography, and performing optical processing on a photosensitive material.

[Photosensitive Material] The photosensitive material can be used without limitation as long as it can cause any photoreaction that can be stored and detected.

For example, it is possible to preferably use a material, particularly a polymer material, which causes photoisomerization or the like depending on the light intensity, resulting in unevenness depending on the reaction amount on the surface of the photosensitive material. The photoisomerization reaction is also desirable in that it exhibits a high-speed photoresponsiveness.

When unevenness is caused on the surface of the photosensitive material,
Since information of the information object is optically recorded as a physically fixed shape, it is overwhelmingly higher than that of an optical microscope such as an atomic force microscope (AFM), a scanning tunneling microscope (STM), or a scanning electron microscope (SEM). There is an advantage that recorded information can be observed by means having a spatial resolution.

It is also possible to use, for example, a light-sensitive material which causes a change in the light refractive index and a change in the light absorptance according to the light intensity. Also in this case, the information recorded as the distribution of the change in the refractive index or the change in the absorptance can be observed / detected by a known appropriate means.

Generally, a polymeric material is suitable as the light-sensitive material, but other kinds of materials can be used. Among the polymeric materials, condensation-based polymeric materials such as polyester, polyamide, polyurethane, and polyurea that can introduce many photoreactive sites such as photoisomerization reaction are particularly suitable.

[Recording Area Surface] As a recording area surface, a flat surface formed of a photosensitive material in a film shape is suitable for convenience of optical recording and observation / detection of recorded information, but an information object is brought into contact therewith. The surface shape is not limited as long as it can be positioned in a state. In optical recording performed as optical processing, a processed surface having an arbitrary shape of an object constitutes a recording area surface. The recording area surface is set to an arbitrary area as needed.

The surface of the recording material is usually placed in an atmospheric environment during optical recording. However, if necessary, the surface of the recording material may be placed under pressure or reduced pressure, or the surface of the recording material may be covered with water droplets when observing microbial organisms. It is also possible to set the main part or the whole of the system in a liquid such as water.

[Information Object] The information object is an object in which known information to be optically recorded is embodied, itself is an object to be analyzed, or a processing means for performing fine optical processing. There are various modes such as.

The information object produces near-field light by irradiation light, and its shape, size, or material is not essentially limited. However, when used for optical information recording or optical processing, it is preferable that its shape, transparency or refractive index is controlled from the viewpoint of accuracy. Also, when the irradiation light is applied only to the surface of the information object in one direction (for example, the surface opposite to the recording area surface), the information object has a certain degree of light transmissivity or is Also, it is preferable that the size is so small that near-field light is also generated on the surface in contact with the recording area surface.

The size of the information object may be less than or equal to the diffraction limit of the irradiation light, but particularly in the case of optical information recording, from the viewpoint of recording high density, the size of the information object is below the diffraction limit. It is desirable to form one recording bit.

[Irradiation Light] The wavelength of the irradiation light is not limited, and one having an appropriate wavelength may be selected and used according to the photosensitive material forming the recording area surface. Near-field light generated in the information object by the irradiation light is absorbed by the photosensitive material, and a predetermined photoreaction occurs due to the absorption, so it is preferable to select a wavelength with high absorption efficiency, and usually a wavelength from the ultraviolet region to the near infrared region is selected. To be selected.

The light source of the irradiation light is not limited, and can be appropriately selected according to the near-field light to be recorded, but the reproducibility in the case of forming unevenness as a recording form and the ease of subsequent analysis are points. Therefore, laser light is more preferable.

The intensity of the irradiation light and the irradiation time are not limited, and may be appropriately selected depending on the photoreactivity of the photosensitive material. When recording the high-speed movement of the information object by repeating short-time exposure, pulsed light with a high peak output can also be used.

Regarding the range of irradiation with the irradiation light, the "area in which the information object is located" means the area range on the surface of the recording area including the information object, and it is a necessary or useful range depending on the purpose of optical recording. It is set arbitrarily.

[Distribution of Near-Field Light] The distribution of near-field light generated in an information object by irradiation light mainly means information on the shape and position of the information object in the first invention, and further information in the second invention. It means information on changes over time such as the movement trajectory, shape, or property of an object.

[0041]

Next, an embodiment of the present invention will be described.

Example 1 Preparation of Recording Area Surface Using a polyurethane polymer compound shown in the following "Chemical formula 2" containing a photoreactive component shown in the following "Chemical formula 1", a thickness of about 1 μm was used. A thin film was prepared, and a film-shaped recording medium having the film surface as a recording area surface was prepared.

[0043]

[Chemical 1]

[0044]

[Chemical 2] Although the description of these synthesis processes is omitted, the melting point of the photoreactive component of the above “Chemical formula 1” is 169 ° C. and the above “Chemical formula 2”.
The glass transition temperature of the polymer compound is 141 ° C, and N-
The intrinsic viscosity at 30 ° C. in methyl-2-pyrrolidone was 0.69 dL / g, and the absorption maximum wavelength was 475 nm.

The above thin film was prepared by dissolving the polymer compound of "Chemical Formula 2" in pyridine to prepare a 6.5 wt% solution, filtering this with a 0.2 μm filter, and rotating at 100 rpm.
It was produced by spin coating on a slide glass under the condition of 0 rpm and vacuum drying at 80 ° C. for 20 hours.

Observation of near-field light distribution in the vicinity of an information object A disk having a hole of 5 mm in diameter was cleaned by ultrasonic cleaning and then placed on the recording medium, and a diameter of 50 mm was put in the hole.
A few drops of water in which a large number of 0 nm polystyrene microspheres were dispersed were dropped. Then, after leaving it until the water evaporates by natural drying, using an air-cooled argon laser (output 20 mW), a laser beam having a wavelength of 488 nm and a beam diameter of about 3 mm is used as it is, a polystyrene microsphere on the recording area surface, that is, the recording medium. Was irradiated on the area where was placed.

After the irradiated recording medium was washed with water to remove some of the microspheres, the recording area surface of the recording medium was observed using an atomic force microscope (SPI-3700 manufactured by Seiko Denshi). The observed images are shown in FIGS. 1 and 2. FIG. 1 and FIG. 2 are observation images of the same image from different angles, and in both figures, the shapes of the microspheres 2 which are the information objects remaining on the recording medium 1 and the shapes of the removed microspheres are shown. Dent 3
And can be observed.

Example 2 The same procedure as in Example 1 was carried out except that polystyrene microspheres having a diameter of 100 nm were used. In the present embodiment, in order to confirm that the formation of the dent is due to the near-field light generated in the information object by using the microsphere having a size of about 1/5 of the wavelength of the irradiation light as the information object. Went to. The observed images are shown in FIG. 3 and FIG.
Shown in. FIG. 3 and FIG. 4 are observation images of the same image from different angles, and the depressions 5 corresponding to the shape of the removed microspheres on the recording medium 4 can be observed from any of the views.

As a comparative example, the observation by an atomic force microscope was carried out in the same manner as in Example 1 without disposing the microspheres on the recording medium. Obviously, however, extraordinary unevenness was observed on the recording medium surface. There wasn't.

[Brief description of drawings]

FIG. 1 is a diagram showing an observation image of an atomic force microscope in an example.

FIG. 2 is a diagram showing an observation image of an atomic force microscope in Examples.

FIG. 3 is a diagram showing an observation image of an atomic force microscope in an example.

FIG. 4 is a diagram showing an observation image of an atomic force microscope in an example.

[Explanation of symbols]

1,4 recording medium 2 microspheres 3,5 dent

─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Riki Egami 154-1 Wago, Hamamatsu City, Shizuoka Prefecture (72) Inventor Hirohiro Sugihara 5-15 Kamijima, Hamamatsu City, Shizuoka Prefecture (72) Inventor Naomichi Okamoto Hamamatsu, Shizuoka Prefecture No. 2578, Masuraku-cho, Yamaguchi, Japan (72) Inventor, Osamu Nakamura 17-11, Hiyoshidai-banbancho, Takatsuki, Osaka (56) References JP-A-11-312335 (JP, A) JP-A-11-250495 (JP, A ) JP-A-11-248621 (JP, A) JP-A-9-7935 (JP, A) JP-A-8-179493 (JP, A) JP-A-1-160564 (JP, A) (58) Field (Int.Cl. ⁷ , DB name) G01J 1/48-1/52 G01N 21/88 B30M 5/26 G03C 1/00 G03F 7/004 521 G11B 7/24

Claims (2)

(57) [Claims] 1. A recording area surface is formed using a photosensitive material capable of causing an arbitrary photoreaction that can be stored and detected, and an information object is positioned in contact with the recording area surface, and then the recording area surface is formed. Of at least the information object is irradiated with light so that the information object on the recording area surface is positioned.
The optical reaction due to the near-field light at the
Based on the phenomenon that occurs stronger than the photoreaction caused by the irradiation light
Then, the optical recording method is characterized in that the distribution of the near-field light generated in the information object is recorded on the photosensitive material as the amount of photoreaction of the photosensitive material. 2. A recording area surface is formed by using a photosensitive material capable of causing an arbitrary photoreaction that can be stored and detected, and an information object which is a movable body is positioned in contact with the recording area surface, The information object on the recording area surface is irradiated with light to illuminate at least the area on the recording area surface where the information object is located .
The optical reaction due to the near-field light at the part where the body is located is the recording area
It is stronger than the photoreaction caused by the irradiation light in other parts of the surface.
Based on this phenomenon, the operation of recording the distribution of the near-field light generated in the information object on the photosensitive material as the photoreaction amount of the photosensitive material is repeated twice or more in response to the movement of the information object. Optical recording method.