JP2000123368A - Method and device for recording information using proximity field light - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable setting and stabilizing distance between a proximity field light generator and a medium surface independently of ambient environment variation when information is recorded on a medium in a method and device for recording information which reversibly record or irreversibly record (process) the information on the recording medium by using proximity field light generated in a proximity region of a proximity field light generator. SOLUTION: The information recording device executing a method for recording information by the proximity field light has the proximity field light generator 4, records the information on the recording medium 5 by using the proximity field light L generated in the proximity region of the device 4 and is provided with a heater 11 (an example of heating devices) heating at least a part 5x of the medium 5 on which information is recorded to a prescribed temp when the information is recorded on the medium 5.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an information recording method and apparatus for recording information on a recording medium using near-field light generated in an area near a near-field light generating device.

[0002]

2. Description of the Related Art Among methods and apparatuses for recording information on a recording medium, there is an information recording method and apparatus using near-field light. Depending on the recording medium, such information may be recorded reversibly, in other words, erasable, or irreversibly, in other words, erasable. The latter can be said to be the processing of a medium for recording information.

In any case, reversible or irreversible recording (processing) of information on a recording medium using near-field light is performed by:
Since near-field light that is not restricted by the “light diffraction limit” is used, attention has been paid to the fact that information can be recorded in units smaller than the wavelength size of light. For example, Applied
Physic Letters (American Institute of Physics): 6
1,142 (1992) describes recording information on a recording medium using near-field light. Also, U.S. Pat.
No. 88,998 describes a photoresist process using near-field light. By the way, the near-field light has such a feature that “the near-field light exists only in the vicinity of the near-field light generator, and the intensity of the near-field light largely depends on the distance from the near-field light generator”. In other words, in order to stably record information on a medium using near-field light, the distance between the surface of the medium on which information is recorded and the near-field light generator must be within the vicinity of the near-field light generator. It is necessary to control so that the distance is kept constant.

[0004] The following two methods are known as typical methods for controlling the distance between the medium surface and the near-field light generator so as to keep it at a constant distance in the area near the near-field light generator. That is, the first method detects the distance between the near-field light generating device and the surface of the medium, and feeds back the driving means for changing the position of the near-field light generating device or the medium based on the detected value. This is a method for controlling the distance between the near-field light generating device and the medium surface. As a means for detecting the distance between the near-field light generating device and the medium surface, means using a tunnel current method, an atomic force method, a shear force method, and the like are known.

The second method is the same as the method used for controlling the distance between a recording head and a magnetic recording medium in a hard disk device (magnetic recording device), and the medium surface is moved at a constant speed. It is operated (moved), and the distance between the near-field light generator and the medium surface is controlled by the levitation force of the near-field light generator due to the air flow generated between the near-field light generator and the medium surface at that time. is there. In most cases, this air flow method does not require a means for detecting the distance between the near-field light generating device and the medium surface.

[0006]

However, according to the study of the present inventors, according to the first method, the value of the distance detected by the distance detecting means varies (including an error) due to a change in the surrounding environment. However, there is a problem that the distance cannot be controlled properly. In the latter method, the flow of air generated between the near-field light generating device and the surface of the medium fluctuates due to fluctuations in the surrounding environment. Is generated.

Accordingly, the present invention provides an information recording method and apparatus for reversibly recording or irreversibly recording (processing) information on a recording medium using near-field light generated in a region near the near-field light generating device. When recording information on a medium, an information recording method and apparatus capable of stabilizing the distance between the near-field light generating device and the surface of the medium irrespective of fluctuations in the surrounding environment, and stabilizing the distance. The task is to provide.

[0008]

Means for Solving the Problems The inventors of the present invention have repeatedly studied to solve the above-mentioned problems, and when near-field light is used, the near-field light generating device and the medium surface are used for recording information on the medium. Have to be very close to each other, so that the surface condition of the medium has a great effect on distance control, but by heating the recording medium, it has been found that environmental changes in the surroundings can hardly affect the surface condition of the medium. Was. This is because the surface condition of the medium, which has been mainly affected by ambient environmental fluctuations, mainly ambient humidity fluctuations, in particular, the amount of adsorbed water on the medium surface is made uniform by heating the medium. It is considered something.

The present invention is based on this finding,
In order to solve the above problems, the following information recording method and apparatus are provided. (1) Information recording method using near-field light This is an information recording method for recording information on a recording medium using near-field light generated in an area near a near-field light generating device, and records information on the medium. An information recording method, wherein at least a portion of the medium where information is recorded is heated to a predetermined temperature. (2) Information recording device using near-field light An information recording device that has a near-field light generating device and records information on a recording medium using near-field light generated in an area near the device. An information recording apparatus, comprising: a heating device for heating at least a portion of the medium on which information is to be recorded to a predetermined temperature when recording the information. “Recording information on a medium” in the information recording method and apparatus of the present invention includes “reversible recording of information on a medium” and “irreversible recording of information on a medium” depending on the recording medium. Both cases are included. The former “reversible recording of information on a medium” is performed so that information can be erased. Further, the latter “irreversible recording of information on a medium” can be said to be “processing of a medium for information recording” and is made in a state where information cannot be erased.

In any case, in the information recording method and apparatus according to the present invention, when recording information on a recording medium, at least a portion of the medium where information is recorded is heated to a predetermined temperature. Further, a near-field light generating device is arranged in proximity to the medium. Then, information is recorded on the recording medium using near-field light generated in a region near the near-field light generating device. In the information recording device, the recording medium is heated by the heating device.

According to this information recording method and apparatus, at the time of recording information on a recording medium, at least a portion of the medium where the information is recorded is heated to a predetermined temperature. The influence of the humidity fluctuation on the surface state of the medium is suppressed, the uniformity of the surface state is easily maintained, and the distance between the near-field light generating device and the medium surface is made constant and stable. Can be Thus, information can be finely and stably recorded on the recording medium without being restricted by the diffraction limit of light.

A method for controlling the distance between the surface of the medium and the near-field light generating device, which can be applied to the information recording method and apparatus according to the present invention, so as to maintain a constant distance within a region near the near-field light generating device. As means, a distance between the near-field light generating device and the surface of the medium is detected, and feedback is provided to driving means for changing the position of the near-field light generating device or the position of the medium based on the detected value. A method and means for controlling the distance between the near-field light generator and the medium surface, and air generated between the near-field light generator and the medium surface by moving the medium surface at a constant speed. A method and means for controlling the distance between the near-field light generating device and the surface of the medium by the levitation force of the near-field light generating device by the flow can be exemplified. In the method and means for controlling the distance between the near-field light generating device and the medium surface based on the distance detection value, the tunnel current method, the atomic force method, and the shear force method are used as the distance detecting device for detecting the distance between the two. An example of a distance detection device based on a method or the like can be given.

[0013] In the information recording method and apparatus according to the present invention, when recording information on the medium, the medium may be heated as a whole, or the near-field light irradiating portion of the medium and its neighboring portions may be heated. It may be heated. In this case, in the information recording device, the following heating device can be exemplified. That is, a heating device that heats the medium as a whole. A heating device for intensively heating a portion of the medium to which near-field light is emitted from the near-field light generating device and a portion in the vicinity thereof.

In any case, the predetermined temperature of the medium at the time of heating the medium is, for example, a temperature at which ambient environmental fluctuations, mainly ambient humidity fluctuations, hardly affect the surface condition of the recording medium, in other words, For example, it can be set to a temperature at which the surface condition of the recording medium is stabilized. The temperature is not limited thereto, but may be, for example, 65 ° C to 75 ° C (for example, approximately 70 ° C).

Further, by heating the medium to a predetermined temperature in advance, it is possible to improve the speed of recording information on the medium using near-field light. This is presumably because the near-field light, which has a lower intensity than the normal propagating light, helps the recording medium to be heated to the information recording temperature, that is, to the temperature at which the information recording change of the medium occurs. The predetermined temperature of the medium when heating the medium can be set lower than the information recording temperature on the medium. In this case, as the heating device in the information recording device, a device that heats the medium to a temperature lower than the information recording temperature can be exemplified.

In any of the information recording methods and apparatuses, the information may be recorded on the medium after detecting that the temperature of the heated portion of the medium is within a predetermined temperature range. Then, the information may be recorded on the medium after it is detected that the humidity of the heated portion of the medium or the vicinity thereof is within a predetermined humidity range.

In such a case, regarding the temperature of the heated portion of the medium and the humidity of the heated portion of the medium or a region in the vicinity thereof, for example, a change in the surrounding environment, mainly a change in the surrounding humidity, is caused by the surface condition of the recording medium. A temperature range and a humidity range that hardly affect the recording medium, in other words, a temperature range and a humidity range in which the surface state of the recording medium is constant are set in advance, and information is recorded on the medium after the detection is detected. By doing so, it is possible to more stably record information on the recording medium.

When recording information on the medium after detecting that the temperature is within the predetermined temperature range, the information recording apparatus detects the temperature of the medium portion heated by the heating device. A temperature detection sensor, and a temperature control unit that controls the heating device so that the temperature of the heated portion of the medium is within a predetermined temperature range based on a detection result by the temperature detection sensor, An information recording device that records information on the medium after the temperature detected by the temperature detection sensor reaches a temperature within the predetermined temperature range can be exemplified.

In the case where information is recorded on the medium after detecting that the medium is within the predetermined humidity range, the information recording device may include the medium portion heated by the heating device or the vicinity thereof. A humidity detection sensor for detecting the humidity of the area, and controlling the heating device based on the detection result by the humidity detection sensor so that the humidity of the heated portion of the medium or the vicinity thereof is within a predetermined humidity range. An example of an information recording device that includes a humidity control unit and records information on the medium after the humidity detected by the humidity detection sensor becomes a humidity within the predetermined humidity range.

[0020]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a side view showing a schematic configuration of an example of an information recording apparatus that performs an information recording method using near-field light according to the present invention. The information recording apparatus shown in FIG. 1 includes a light emitting unit 100, a medium storage unit 200, and a main control unit CONT.
, And information can be recorded on the recording medium 5. That is, under the direction of the main control unit CONT, the near-field light L is emitted from the light emitting unit 100 to the medium 5 stored in the medium storage unit 200, and information is recorded on the medium 5. In addition,
This information recording apparatus can perform reversible recording of information on the medium and irreversible recording (processing) of information on the medium according to the recording medium.

The light emitting section 100 includes a laser light source 1, an optical coupling device 3, and a near-field light generating device 4. The laser light source 1 is connected to the main control unit CONT (see FIG. 4), and can emit the laser beam 2 toward the optical coupling device 3 under the instruction of the main control unit CONT. The optical coupling device 3 can irradiate the near-field light generating device 4 with the laser light 2 from the laser light source 1. The near-field light generating device 4 can convert the laser light 2 from the optical coupling device 3 into near-field light L.

FIG. 2 is a sectional view of the near-field light generating device 4. The near-field light generating device 4 includes an optical fiber 4a having a core portion 41 and a clad portion 42 in this example. The optical fiber 4a is provided with a coating film 4c by evaporating aluminum around the tip 4b after the tip 4b is sharpened by chemical etching. Then, only the aluminum at the tip of the sharpened portion is removed by chemical etching, so that in this example, an opening 4d having an opening diameter of about 100 nm is formed. As a result, the near-field light generating device 4 allows the laser light 2 from the optical coupling device 3 to be incident on the non-sharpened side 4e of the optical fiber 4a, so that the near-field light is transmitted from the near-sharpened opening 4d. Light L can be emitted.

The medium accommodating section 200 is provided with a rotation drive device (not shown), and can accommodate the disk-shaped recording medium 5. The medium surface 5a of the medium 5 is moved by the rotation of the rotation drive device. The main control unit CONT is mainly composed of a computer and controls the entire information recording apparatus. As described above, the main control unit CONT is connected to the laser light source 1 (see FIG. 4), and further includes a distance detection device 300, a near-field light generation device driving unit 400, and a temperature control unit by a shear force method described later. It is connected to the medium heating unit 500 via CONT1 (see FIG. 4). The main control unit CONT controls the emission timing of the laser light 2 from the laser light source 1 or controls the near-field light generation device 4 by the drive unit 400 based on the detection value of the distance detection device 300.
Control of the distance between the media and the medium surface 5a is performed. This control will be described later in detail.

The distance detecting device 300 includes a laser light source 6 for shear force detection different from the laser light source 1, a two-part photodiode 8, and lenses 60 and 80. The laser light source 6 is connected to the main control unit CONT (see FIG. 4), and can emit a shear force detection laser beam 7 (in this example, a wavelength of 780 nm and an output power of 1 mW) under the instruction of the main control unit CONT. The light can be applied to the near-field light generator 4 through the lens 60. In this case, the spot diameter of the light in the light irradiation unit is made larger than the width of the portion of the near-field light generator 4 where the laser light 7 is irradiated.

The two-part photodiode 8 includes photodiodes 8a and 8b, and is connected to the main control unit CONT (see FIG. 4). Photodiodes 8a, 8b
, Light having a shadow of the near-field light generator 4 after irradiating the near-field light generator 4 is incident through the lens 80, and the incident light to each photodiode is electrically It is converted into a signal (photoelectric conversion). This signal is detected as a light amount by the electric circuits 8a 'and 8b' and sent to the main control unit CONT. Main control unit CONT
Detects the position of the near-field light generating device 4 in a predetermined direction (x direction in FIG. 1) in the form of a relative value to the irradiation beam position by comparing the light amounts detected via the photodiodes 8a and 8b. Position detecting means.

The near-field light generator driving section 400 is denoted by x in FIG.
A driving element (driving unit) 9 in the direction and a driving element (driving unit) 10 in the ascending / descending direction (z direction in FIG. 1) of the near-field light generator. The driving element 9 is connected to the main control unit CONT (see FIG. 4), and can apply vibration in the x direction to the near-field light generating device 4 under the instruction of the main control unit CONT. In this example, the vibration frequency applied to the near-field light generator 4 is substantially equal to the resonance frequency of the near-field light generator 4 and
0 kHz, amplitude is 50 nm. The driving element 10 is connected to the main control unit CONT (see FIG. 4), and moves the near-field light generating device 4 vibrated by the driving element 9 closer to the medium 5 under the instruction of the main control unit CONT. You can keep it away from 5.

When the near-field light generating device 4 vibrated by the driving element 9 is brought closer to the medium 5, when the distance between them approaches a certain distance, the amplitude and phase of the vibration of the near-field light generating device 4 change. The cause is considered to be the influence of the water adsorbed on the medium surface 5a. Under the influence, the amplitude gradually decreases, and the phase shifts as compared with the initial stage (when the distance between the two is long). By utilizing this fact, a relative distance between the two can be known by detecting a change in amplitude or a shift in phase through the two-division photodiode 8.
That is, the main control unit CONT gives feedback to the drive element 10 that is driven in the z direction in FIG. 1 based on the relative distance change in the x direction detected by the two-part photodiode 8. Thereby, the driving element 10 is controlled,
The distance between the device 4 and the medium 5 can be adjusted to the target value.

FIG. 3 shows a sectional view of the recording medium 5. Medium 5
As shown in FIG. 3, a recording layer 5c made of a cyanine dye was applied on a polycarbonate substrate 5b by spin coating. In this case, the near-field light generating device 4 is arranged close to the recording layer 5c side of the medium 5. The medium heating unit 500 includes a recording medium heating heater 11 (an example of a heating device), a heater power supply PW, and a thermistor TH (an example of a temperature detection sensor). The heater 11 is provided in the medium container 2
It is provided below the medium 5 housed in 00 and is connected to the power supply PW. Thereby, the medium 5 can be entirely heated. The power supply PW is connected to the temperature control unit CONT1 (see FIG. 4), and can supply electricity to the heater 11 under the instruction of the temperature control unit CONT1. The thermistor TH is disposed in contact with the medium surface 5a, and can detect the temperature of the medium 5. Further, it is connected to the temperature control unit CONT1 (see FIG. 4), and the detection result can be sent to the temperature control unit CONT1.

The temperature control unit CONT1 includes a main control unit CON.
T (see FIG. 4), and based on the detection result by the thermistor TH, the medium 5
When the temperature is lower than the lower limit value of the predetermined temperature range, in this example, lower than 65 ° C., the power supply PW is turned on. Turn off PW. Thereby, the heater 11 can be controlled so that the temperature of the medium 5 can be maintained at a predetermined temperature, approximately 70 ° C. in this example. When the temperature of the medium 5 is out of the predetermined temperature range, the temperature control unit CONT1 sends an information recording stop signal to stop recording information on the medium 5 to the main control unit CONT1.
When the temperature is within the predetermined temperature range, an information recording start signal for signaling the start of information recording on the medium 5 is sent to the main control unit CONT. Thereby, information recording on the medium 5 can be controlled.
The predetermined temperature of the medium 5 is set lower than the information recording temperature on the medium 5 (140 ° C. in this example).

According to the information recording apparatus described above, the medium 5 is driven to rotate when recording information on the recording medium 5. When the power supply PW is turned on and the heater 11 is energized, the entire medium 5 is heated by the heater 11 and the medium 5 is heated.
Is heated to a predetermined temperature. The temperature of the medium 5 is detected by the thermistor TH,
The detection result is sent to the temperature control unit CONT1. In the temperature control unit CONT1, when the temperature detected by the thermistor TH falls within a predetermined temperature range, in this example, between 65 ° C. and 75 ° C., the information recording start signal is sent to the main control unit CONT.
Send to

When an information recording start signal is sent from the temperature control unit CONT1 to the main control unit CONT, information recording on the medium 5 is started. That is, first, detection and control of the distance between the near-field light generating device 4 and the medium surface 5a are performed. In addition,
The method of detecting the distance between the near-field light generating device 4 and the medium surface 5a applied to this example is known as a shear force method.

The near-field light generating device driving section 400 applies vibration to the near-field light generating device 4 in the x direction in FIG. 1 by the driving element 9 mounted on the near-field light generating device 4. Near-field light generator 4 vibrated in the x direction by drive element 9
Is brought closer to the medium surface 5 a by the driving element 10. In the distance detecting device 300, the near-field light generating device 4 is irradiated with the shear-force detecting laser light 7 emitted from the shear-force detecting laser light source 6. At this time, in the irradiating section, the spot diameter of the light is larger than the width of the laser light irradiating portion of the near-field light generating device 4. The light after irradiating the near-field light generator 4 has a shadow of the near-field light generator 4. This light is photoelectrically converted by the two-segment photodiode 8, and after detecting the light amount, the detection signal is sent to the main control unit CONT. The main control unit CONT compares the amounts of light detected by the photodiodes 8a and 8b, thereby obtaining the near-field light generator 4.
Of the amplitude (or phase) of the vibration, and further the distance between the device 4 and the medium surface 5a. Then, feedback is applied to the drive element 10 based on the detected relative distance between the near-field light generator 4 and the medium surface 5a. As a result, the distance between the two is adjusted to the target value.

Next, laser light 2 is emitted from the laser light source 1. The laser light 2 emitted from the laser light source 1 enters the near-field light generator 4 via the optical coupling device 3 and is converted into near-field light L here. The converted near-field light L is irradiated onto the medium surface 5a. Thereby, information is recorded on the medium 5. According to this information recording apparatus, at the time of recording information on the recording medium 5, at least a portion 5x of the medium 5 where the information is recorded is heated to a predetermined temperature and kept at a constant temperature. In particular, the influence of the ambient humidity fluctuation on the surface state of the medium 5 is suppressed, and the state of the surface 5a of the recording layer 5c (see FIG. 3) (mainly the state affected by the amount of adsorbed water on the medium surface 5a) is uniform. The property is easily maintained. As a result, variation in the detected value of the relative distance between the near-field light generating device 4 and the medium surface 5a is suppressed, and the distance can be kept constant and stably. Thus, information can be recorded on the medium 5 finely and stably without being restricted by the diffraction limit of light.

Next, another example of the information recording apparatus for carrying out the information recording method according to the present invention will be described with reference to FIG. The information recording apparatus shown in FIG. 5 is the same as the information recording apparatus shown in FIG.
Instead of T1, a medium heating unit 500 'and a humidity control unit CON
T2 is provided. Other points are the same as the apparatus of FIG.
Parts having the same configuration and operation are denoted by the same reference numerals. Note that the distance detection device 300 slightly changes the arrangement of the device components and the like, but performs substantially the same operation according to the same principle as the device of FIG. The recording medium 5 is the same as that applied to the apparatus of FIG.

The information recording apparatus shown in FIG.
The description will focus on the differences from the apparatus of FIG. Medium heating unit 5
00 ′ is a heating laser light source 13 (an example of a heating device),
The condenser lens 15 includes a humidity detection sensor HU. The laser light source 13 is connected to the humidity control unit CONT2 (see FIG. 6). Under the instruction of the humidity control unit CONT2, the laser light 14 (in this example, wavelength 532 nm, output power 20 m)
W) can be injected. The laser light source 13 is the laser light 1
4 is applied to the surface of the recording layer 5c (see FIG. 3) of the medium 5 facing the near-field light generator 4 via the condenser lens 15. In this example, the spot diameter of the laser light 14 on the surface of the recording layer 5c is about 3 μm. Thereby, the recording medium 5
The portion 5y irradiated with the near-field light L from the near-field light generating device 4 and its vicinity can be intensively heated.

The humidity detecting sensor HU is disposed in a region near the medium portion heated by the laser light source 13, and can detect the humidity in the region. Also, the humidity control unit CONT2
(See FIG. 6), and the detection result can be sent to the humidity control unit CONT2. Humidity control unit CON
T2 is connected to the main control unit CONT (see FIG. 6), and based on the detection result by the humidity detection sensor HU,
When the light source 13 is off, the humidity in the area near the heated portion 5y of the medium 5 is equal to the upper limit value of the predetermined humidity range.
When it becomes higher than 5% RH, the light source 13 is turned on and the light source 13 is turned on.
Is in the on state, the lower limit of the predetermined humidity range, in this example, 25%
When it becomes lower than RH, the light source 13 is turned off. Thereby, the light source 13 can be controlled so that the humidity of the medium 5 can be maintained at a predetermined humidity, approximately 30% RH in this example. When the humidity of the medium 5 is out of the predetermined humidity range, the humidity control unit CONT2 sends an information recording stop signal to the main control unit CONT to signal the stop of the information recording on the medium 5; 5 to the main control unit CONT. Thereby, information recording on the medium 5 can be controlled.

According to the information recording apparatus shown in FIG. 5, when recording information on the recording medium 5, the medium 5 is driven to rotate. Laser light 14 is emitted from the laser light source 13,
The medium 5 is irradiated with the laser light 14. A portion 5y of the medium 5 where at least information is recorded by the laser light source 13
Is heated to a predetermined temperature. The humidity in the area near the heated portion of the medium 5 is detected by the humidity detection sensor HU, and the detection result is sent to the humidity control unit CONT2. The humidity control unit CONT2 sends an information recording start signal to the main control unit CONT when the humidity detected by the humidity detection sensor HU falls within a predetermined humidity range, in this example, 25% to 35%.

According to this information recording apparatus, the portion 5y of the recording medium 5 to which the near-field light L is irradiated from the near-field light generator 4 and the vicinity thereof are concentrated at a predetermined temperature by the heating laser light source 13. Therefore, the same effect as that of the information recording apparatus shown in FIG. 1 can be obtained. next,
Still another example of the information recording apparatus that performs the information recording method according to the present invention will be described with reference to FIG.

The information recording apparatus shown in FIG.
0 ′, a medium storage unit 200 ′, and a main control unit CONT ′, and can record information on the recording medium 85 or read (reproduce) information from the recording medium 85.
That is, under the instruction of the main control unit CONT ′, the near-field light L
Is irradiated from the light emitting unit 100 ′ to the medium 85 stored in the medium storage unit 200 ′, and information is recorded on the medium 85.
Alternatively, the amount of light reflected from the medium 85 is detected to reproduce information from the medium 85. The information recording apparatus can perform reversible recording of information on the medium and irreversible recording (processing) of information on the medium according to the recording medium.

The light emitting section 100 ′ includes a laser light source 81, an optical coupling device 83, and a near-field light generating device 84. The laser light source 81 is connected to the main control unit CONT ′ (see FIG. 10), and under the instruction of the main control unit CONT ′,
The laser beam 82 for recording information or detecting the amount of reflected light can be emitted toward the optical coupling device 83. The optical coupling device 83 can irradiate the near-field light generating device 84 with the laser light 82 from the laser light source 81. The near-field light generating device 84 can convert the laser light 82 from the optical coupling device 83 into near-field light L.

FIG. 8 is a more detailed side view of the near-field light generating device 84 shown in FIG. The near-field light generating device 84 has a small opening 84b provided in a head 84a that floats by a floating force caused by an air flow generated by rotation of a medium 85. The head 84a has an opening entrance 84c on the wide side of the minute opening 84b (in this example, an opening diameter of 600 nm) and an opening exit 84d on the narrow side of the minute opening 84b (in this example, an opening diameter of 2 nm).
00 nm). As a result, the near-field light generating device 84 can emit the near-field light L from the opening exit 84d when the laser light 82 from the optical coupling device 83 is incident on the opening entrance 84c.

The medium accommodating section 200 'is provided with a rotation driving device (not shown), and can accommodate a disk-shaped recording medium 85. The medium surface 85a of the medium 85 is moved by the rotation of the rotation driving device. The main control unit CONT 'is mainly composed of a computer and controls the entire information recording apparatus. The main control unit CONT ′ is connected to the laser light source 81 as described above, and is connected to the medium heating unit 500 ″ via a reflected light detection device 600 and a temperature control unit CONT3 described later (FIG. 10) The main control unit CONT ′ controls the emission timing of the laser light 82 of the laser light source 81 and the reflected light amount detection device 60.
Reading information from the medium 85 is performed based on the detection result of “0”.

FIG. 9 is a sectional view of the recording medium 85. As shown in FIG. 9, the medium 85 is formed by sequentially applying a subbing layer 85c made of polyimide and a recording layer 85d made of cyanine dye on a glass substrate 85b by spin coating. In this case, the near-field light generating device 84 is disposed close to the recording layer 85d. In the information recording device shown in FIG. 7, the distance between the near-field light generating device 84 and the medium 85 is not detected, and the medium surface 85a is moved at a constant speed. Medium surface 85
The distance between the near-field light generating device 84 and the medium surface 85a is controlled by the levitation force of the near-field light generating device 84 due to the airflow generated between the medium and the medium surface 85a.

The medium heating section 500 "includes a recording medium heating heater 89 (an example of a heating device), a heater power supply PW", and a thermistor TH "(an example of a temperature detection sensor).
The heater 89 is configured to store the medium 85 stored in the medium storage 200 ′.
And is connected to a power supply PW ". Thereby, the medium 85 can be entirely heated. The power supply PW" is connected to the temperature control unit CONT3 (FIG. 1).
0), the heater 8 under the instruction of the temperature control unit CONT3.
9 can be energized. The thermistor TH "is disposed in contact with the medium surface 85a and can detect the temperature of the medium 85. The thermistor TH" is connected to the temperature control unit CONT3 (see FIG. 10), and sends the detection result to the temperature control unit CONT3. Can be.

The temperature control unit CONT3 includes a main control unit CON.
T ′ (see FIG. 10) and the thermistor T
Based on the detection result based on H ″, the temperature of the medium 85 is set to the lower limit value of the predetermined temperature range when the power supply PW ″ is off, in this example,
When the temperature is lower than 65 ° C., the power supply PW ″ is turned on. When the power is higher than 75 ° C. in the present embodiment, the power supply PW ″ is turned off. Thereby, the medium 8
The heater 89 can be controlled so that the temperature of No. 5 can be maintained at a predetermined temperature, approximately 70 ° C. in this example. The temperature control unit CON
T3 is the medium 8 when the temperature of the medium 85 is out of the predetermined temperature range.
5 is sent to the main control unit CONT 'to signal the stop of information recording / reproducing to the main control unit CONT'. It is sent to the main control unit CONT '. Thereby, information recording / reproduction on the medium 85 can be controlled. Note that the predetermined temperature of the medium 85 is set to a temperature substantially equal to the information recording temperature on the medium 85 (70 ° C. in this example).

The reflected light amount detecting device 600 includes a photodiode 88 and a condenser lens 87. Condensing lens 8
7 can collect the reflected light 86 converted into ordinary propagation light at the time of irradiation on the medium surface 85a to the photodiode 88. The photodiode 88 is connected to the main control unit CONT ′ (see FIG. 10), and can convert light collected by the condenser lens 87 into an electric signal (photoelectric conversion) according to the amount of light. This signal is detected as a light quantity by the electric circuit 88 'and sent to the main control unit CONT'. The main control unit CONT ′ determines the recording information based on the difference in the amount of reflected light from the information recording portion and the unrecorded portion of the medium 85 detected through the photodiode 88, that is, the difference in the amount of reflected light due to the difference in the reflectance between the two portions. Information reproducing means for reading out (reproducing) the information.

According to the information recording apparatus shown in FIG. 7, when recording information on the recording medium 85 or reproducing information from the recording medium 85, the medium 85 is rotated. The near-field light generating device 84 floats by a levitation force due to the airflow generated by the rotation of the medium 85, and the distance between the near-field light generating device 84 and the medium surface 85a is controlled. Power supply P
W "is turned on, the heater 89 is energized, the entirety of the medium 85 is heated by the heater 89, and the portion 85z of the medium 85 where information is recorded is heated to a predetermined temperature. The thermistor TH" The temperature is detected, and the detection result is sent to the temperature control unit CONT3. Temperature control unit CO
When the temperature detected by the thermistor TH "falls within the predetermined temperature range, the NT3 sends a start signal to the main control unit CONT '.
Send to

When a start signal is sent from the temperature control unit CONT3 to the main control unit CONT ', information recording or information reproduction on the medium 85 is started. That is, the laser light source 81
The laser light 82 is emitted from. The laser light 82 emitted from the laser light source 81 enters the near-field light generator 84 via the optical coupling device 83, and is converted into the near-field light L here. The converted near-field light L is irradiated onto the medium surface 85a. Thus, information is recorded on the medium 85. Alternatively, the reflected light 86 from the medium 85 is
0, and the signal is detected as a light amount in the main control unit CON.
Sent to T '. In the main control unit CONT ′, the detecting device 6
The recording information is read from the difference in the amount of reflected light transmitted from 00 due to the difference in reflectance between the information recording portion and the information non-recording portion of the medium 85.

According to this information recording apparatus, the recording medium 85
When recording information or reading information to
At least a portion 85z of the medium 85 where information is recorded
Is heated to a predetermined temperature and is maintained at a constant temperature, so that the influence of ambient environmental fluctuations, mainly ambient humidity fluctuations, on the surface condition of the medium 85 is suppressed, and the surface 85a of the recording layer 85d (see FIG. 9) is reduced. The uniformity of the state (mainly the state affected by the amount of adsorbed water on the medium surface 85a) is easily maintained, and the distance between the near-field light generating device 84 and the medium surface 85a is made constant and stable. Can be maintained.

Next, a performance evaluation experiment was performed on the information recording apparatus of the present invention, which will be described below along with a comparative experiment. The medium 5 is accommodated in the information recording device shown in FIGS.
The value detected by the shear force method of the divided photodiode 8 with respect to the relative distance between the near-field light generator 4 and the medium 5 depending on whether the medium 5 is heated or not heated, that is, the near-field light generator 4 was evaluated for variations in the amplitude of the x-direction vibration.

The experiment was performed as follows. That is,
In the evaluation experiment 1a, the medium 5 was heated to 70 ° C. by the heater 11 using the information recording device shown in FIG. 1, and in the evaluation experiment 1b, the heating laser light source 13 was used using the information recording device shown in FIG. The medium 5 is irradiated with the laser beam 14 of FIG. 1 and the humidity near the laser beam irradiation site is set to approximately 30%. In Comparative Experiment 1, the heater 1 was heated using the information recording apparatus shown in FIG.
1, the near-field light generating device 4 is not heated.
The divided photodiode 8 was detected by the shear force method when the sample was brought close to the medium 5. In each experiment, the ambient temperature and humidity were 25 ° C., 30% and 25%, respectively.
The test was performed in an environment of 70 ° C. and 70%.

The experimental results are shown in FIGS. FIG.
1 and 12 are graphs showing the results of evaluation experiments 1a and 1b, respectively. FIG. 11 shows the information recording apparatus shown in FIG. 1 and FIG. 12 shows the information recording apparatus shown in FIG. 4 is a graph showing a relationship between a relative distance between the near-field light generator 4 and the medium 5 and an amplitude of the near-field light generator 4.

FIG. 13 is a graph showing the results of Comparative Experiment 1. In the information recording apparatus shown in FIG. 1, the relative distance between the near-field light generator 4 and the medium 5 when the medium 5 was not heated. 6 is a graph showing the relationship between the amplitude of the near-field light generator 4 and the near-field light generator 4. In the graphs shown in FIGS. 11 to 13, the solid lines indicate that the ambient temperature and the humidity
In the case of 0%, the broken line indicates that the ambient temperature and the humidity environment are 25
℃, 70%.

In the evaluation experiments 1a and 1b, as shown in FIGS. 11 and 12, there is no significant difference between the two detection results for the case of the solid line and the case of the broken line, and the near-field light generation is not affected by the humidity of the surrounding environment. It can be seen that the relative distance between the device 4 and the medium 5 can be detected. On the other hand, in the comparative experiment 1, as shown in FIG. 13, there is a difference between the two detection results in the case of the solid line and the case of the broken line. It can be seen that the detected values of the relative distance to the medium 5 are different.

Although the cause of the difference between the results of the evaluation experiments 1a and 1b and the comparison experiment 1 is not clear, the amount of water adsorbed on the medium 5 depends on the relative distance between the near-field light generator 4 and the medium 5. It is considered that the detection value is affected. In any case, by heating the medium 5, it can be seen that the relative distance between the near-field light generating device 4 and the medium 5 can be stably detected regardless of the surrounding environment fluctuation.

Although the graph showing the experimental results is not shown, the medium 5 is not heated by the heater 11 using the information recording apparatus shown in FIG. 25 ° C, 30% and 35 ° C, 30 respectively
An experiment was conducted to evaluate the variation in the detection values of the divided photodiodes 8 by the shear force method when the near-field light generator 4 was brought closer to the medium 5 in an environment of%. as a result,
The graph of the detection signal by the shear force method shows the case where the ambient temperature and the humidity environment are 25 ° C. and
There was no significant difference between the case of 30 ° C. and 30%. This also indicates that the humidity of the surrounding environment and the amount of water adsorbed on the medium surface have an effect on the distance detection by the shear force method. Next, the disk-shaped medium 8 is inserted into the information recording apparatus shown in FIG.
5 is accommodated, and the medium 85 is
Is rotated, and the near-field light L for each predetermined rotation angle of the medium 85 is determined depending on whether the medium 85 is heated or not.
The detection value of the reflected light 86 reflected from the medium 85 by irradiation by the reflected light amount detection device 600, that is, the reflected light 86
Were evaluated for variations in the amount of reflected light.

The experiment was performed as follows. That is,
In evaluation experiment 2, the medium 85 was heated to 70 ° C. by the heater 89 using the information recording device shown in FIG. 7, and in comparative experiment 2, the heater 8 was heated using the information recording device shown in FIG.
9 does not heat the medium 85, emits a laser beam 82 for detecting the amount of reflected light from the laser light source 81, and rotates the medium 85 on which no information is recorded while rotating the medium 85. The medium 85 is irradiated with near-field light L for detecting the amount of reflected light from the near-field light generating device 84 that floats in the above manner, and the amount of reflected light 86 from the medium 85 is detected via the photodiode 88. In all experiments, the ambient temperature and humidity were 25 ° C., 30% and 25 ° C., respectively.
The test was performed in a 0% environment.

The amount of the reflected light 86 depends on the medium surface 85a.
, It is considered to be greatly affected by the distance between the near-field light generating device 84 and the medium surface 85a. The experimental results are shown in FIGS. FIG.
7 is a graph showing the result of evaluation experiment 2. In the information recording apparatus shown in FIG.
5 is a graph showing the amount of reflected light of reflected light 86 for each predetermined rotation angle of No. 5;

FIG. 15 is a graph showing the results of Comparative Experiment 2. In the information recording apparatus shown in FIG. 7, the amount of reflected light 86 of the reflected light 86 at each predetermined rotation angle of the medium 85 when the medium 85 is not heated is shown. It is a graph shown. In the graphs shown in FIGS. 14 and 15, the solid line indicates the ambient temperature, and the dashed line indicates the ambient temperature when the humidity environment is 25 ° C. and 30%, respectively.
The case where the humidity environment is 25 ° C. and 70%, respectively.

In the evaluation experiment 2, as shown in FIG. 14, there is no large difference between the two detection results for the case of the solid line and the case of the broken line, and the reflected light amount detecting device 6 is not affected by the humidity of the surrounding environment.
It can be seen that 00 detects the amount of reflected light 86.
That is, it is understood that the distance between the near-field light generating device 84 and the medium surface 85a is constant and stabilized without affecting the humidity of the surrounding environment. In contrast, in Comparative Experiment 2,
As shown in FIG. 15, there is a difference between the two detection results for the case of the solid line and the case of the broken line, and it can be seen that the amount of the reflected light 86 fluctuates due to the humidity of the surrounding environment. That is, it is considered that the distance between the near-field light generator 84 and the medium surface 85a fluctuates due to the influence of the humidity of the surrounding environment.

The cause of the difference between the results of the evaluation experiment 2 and the comparison experiment 2 is not clear, but the flow of air generated by the rotation of the medium 85, that is, the movement of air molecules is affected by the effect of the adsorbed water on the medium surface 85a. , The near-field light generating device 4 and the medium 85
Is considered to change. In any case, the amount of reflected light is stabilized by heating the medium. Next, the recording efficiency of information on a recording medium was evaluated using near-field light. By the way, the recording efficiency of information on the recording medium is determined by irradiating the recording medium on which the information is recorded with light for information reproduction,
By detecting the amount of light reflected from the medium, the efficiency of recording information on the recording medium can be determined. That is, the larger the amount of reflected light, the better the recording efficiency.

Therefore, although not shown, the information recording apparatus shown in FIG. 1 is provided with a reflected light amount detecting device having the same function as the reflected light amount detecting device 600 shown in FIG. To emit light,
The reflected light from the medium 5 with respect to the irradiation time of the information reproducing light from the light emitting unit 100 to the medium 5 depending on whether the medium 5 is heated while the medium 5 is stored in the information recording apparatus. The efficiency of recording information on the medium 5 was evaluated.

The experiment was performed as follows. That is,
In evaluation experiment 3, the medium 5 was heated to 70 ° C. by the heater 11 using the information recording apparatus shown in FIG. 1, and in comparative experiment 3, the heater 11 was heated using the information recording apparatus shown in FIG.
Without heating the medium 5, the near-field light generator 4 irradiates the medium 5 with recording light to record information, and then irradiates the medium 5 with reproduction light, and the reflected light amount not shown. The amount of reflected light from the medium 5 was detected by the detection device. In each of the experiments, information recording was performed in an environment at a temperature of 25 ° C. and a humidity of 30%, respectively. The surrounding environment at the time of irradiation of the reproduction light is 25 ° C. and 30%, respectively, of the humidity, and the medium is not heated by the heater 11 during the irradiation of the reproduction light.

FIG. 16 shows the results of the experiment. In FIG. 16, the solid line shows the result of the evaluation experiment 3, the medium 5 is heated when the information recording is performed on the medium 5, and the broken line shows the result of the comparative experiment 3, and the medium 5 is not heated when recording the information. The relationship between the amount of reflected light from the medium 5 due to the information reproducing light on the medium 5 and the efficiency of recording information on the medium 5 is shown below. In FIG. 16, the horizontal axis indicates the light irradiation time during information recording.

As shown in FIG. 16, the medium 11 is
It can be seen that the recording speed when information is recorded on the medium 5 using the near-field light L is improved by heating. This is the case of near-field light that is weaker than normal propagating light,
If the medium is not heated by the heater, only the near-field light heats the medium, so that it takes time to reach the information recording temperature, that is, the temperature at which the information recording change occurs. It is believed to assist in media heating. Therefore, it can be understood that the medium heating by the heater 11 is effective in maintaining the distance between the near-field light generating device 4 and the medium 5 constant, and also has the effect of increasing the recording speed by the near-field light L. .

[0066]

According to the present invention, an information recording method for reversibly recording or irreversibly recording (processing) information on a recording medium using near-field light generated in a region near the near-field light generating device. And when the information is recorded on the medium, the distance between the near-field light generating device and the surface of the medium can be kept constant and stable regardless of the fluctuation of the surrounding environment. An information recording method and apparatus capable of stably recording information can be provided.

Further, according to the present invention, it is possible to provide an information recording method and apparatus capable of performing information recording on a recording medium by near-field light at a higher speed than before.

[Brief description of the drawings]

FIG. 1 is a side view illustrating a schematic configuration of an example of an information recording apparatus that performs an information recording method using near-field light according to the present invention.

FIG. 2 is a sectional view of the near-field light generating device shown in FIG.

3 is a sectional view of a recording medium accommodated in the information recording device shown in FIG.

FIG. 4 is a schematic block diagram showing one example of a control circuit of the information recording device shown in FIG.

FIG. 5 shows another example of the information recording apparatus for performing the information recording method according to the present invention.

6 is a schematic block diagram showing one example of a control circuit of the information recording device shown in FIG.

FIG. 7 shows still another example of the information recording apparatus for performing the information recording method according to the present invention.

8 is a more detailed side view of the near-field light generating device shown in FIG.

9 is a sectional view of a recording medium accommodated in the information recording device shown in FIG.

FIG. 10 is a schematic block diagram showing one example of a control circuit of the information recording device shown in FIG.

11 is a graph showing the results of an evaluation experiment. In the information recording apparatus shown in FIG. 1, the relative distance between the near-field light generator and the medium when the medium is heated and the amplitude of the near-field light generator are shown. 6 is a graph showing a relationship with the graph.

12 is a graph showing the results of an evaluation experiment. In the information recording apparatus shown in FIG. 5, the relative distance between the near-field light generator and the medium when the medium is heated and the amplitude of the near-field light generator are shown. 6 is a graph showing a relationship with the graph.

13 is a graph showing a result of a comparative experiment, in which the relative distance between the near-field light generator and the medium when the medium is not heated and the near-field light generator in the information recording apparatus shown in FIG. 6 is a graph showing a relationship between the amplitude and the amplitude.

14 is a graph showing the results of an evaluation experiment, and is a graph showing the amount of reflected light for each predetermined rotation angle of the medium when the medium is heated in the information recording device shown in FIG.

FIG. 15 is a graph showing the results of a comparative experiment, and is a graph showing the amount of reflected light at each predetermined rotation angle of the medium when the medium is not heated in the information recording apparatus shown in FIG. 7;

16 is a graph showing the relationship between the irradiation time of information recording light on a medium and the amount of reflected light from the medium, that is, the efficiency of recording information on the medium, in the information recording apparatus shown in FIG.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Laser light source 2 Laser light 3 Optical coupling device 4 Near-field light generating device 41 Core part 42 Cladding part 4a Optical fiber 4b Optical fiber tip part 4c Coating film 4d Opening 5 Recording medium 5a Medium surface 5b Polycarbonate substrate 5c Recording layer 5x A portion where medium information is recorded 5y A portion of the medium irradiated with near-field light from the near-field light generator 6 A laser light source for shear force detection 60 Lens 7 A laser light for shear force detection 8 Two-divided photodiodes 8a, 8b Photodiodes 8a ', 8b' Electric circuit for light quantity detection 80 Lens 9 X-direction drive element 10 Z-direction drive element 11 Heater for recording medium heating (one example of heating device) 13 Laser light source for heating (one example of heating device) 14 Laser light 15 Condensing lens 81 Laser light source 82 Laser light 83 Optical coupling device Reference Signs List 4 near-field light generating device 84a head 84b minute opening 84c opening entrance 84d opening exit 85 recording medium 85a medium surface 85b glass substrate 85c undercoat layer 85d recording layer 86 reflected light 87 condensing lens 88 photodiode 88 'light quantity detection electric circuit 89 Heater for heating recording medium (one example of heating device) 100, 100 'Light emitting unit 200, 200' Medium storage unit 300 Distance detecting device by shear force method 400 Near-field light generating device driving unit 500, 500 ', 500 " Medium heating unit 600 Reflected light amount detection device L Near-field light PW, PW "Heater power supply TH, TH" Thermistor (an example of a temperature detection sensor) HU Humidity detection sensor CONT, CONT 'Main control unit CONT1, CONT3 Temperature control unit CONT2 Humidity Control unit

Claims (12)

[Claims] An information recording method for recording information on a recording medium using near-field light generated in an area near a near-field light generating device. An information recording method comprising: heating a portion where recording is performed to a predetermined temperature. 2. The information recording method according to claim 1, wherein when recording information on the medium, the medium is heated as a whole. 3. The information recording method according to claim 1, wherein, when information is recorded on the medium, a near-field light irradiation part of the medium and a part in the vicinity thereof are heated. 4. The information recording method according to claim 1, wherein a predetermined temperature of the medium when heating the medium is set lower than an information recording temperature on the medium. 5. The information recording apparatus according to claim 1, wherein the information recording on the medium is performed after detecting that the temperature of the heated portion of the medium is within a predetermined temperature range. Method. 6. The information recording apparatus according to claim 1, wherein the recording of the information on the medium is performed after detecting that the humidity of the heated portion of the medium or a region in the vicinity thereof is within a predetermined humidity range. Information recording method described. 7. An information recording apparatus having a near-field light generating device and recording information on a recording medium using near-field light generated in a region near the device. An information recording device comprising a heating device for heating at least a portion of the medium on which information is to be recorded to a predetermined temperature. 8. An information recording apparatus according to claim 7, wherein said heating device heats said medium as a whole. 9. The information recording apparatus according to claim 7, wherein the heating device intensively heats a portion of the medium to which near-field light is irradiated from the near-field light generating device and a portion in the vicinity thereof. 10. The heating device heats the medium to a temperature lower than its information recording temperature.
Or the information recording device according to 9. 11. A temperature detection sensor for detecting a temperature of the medium portion heated by the heating device, and a temperature of a heated portion of the medium is set within a predetermined temperature range based on a detection result by the temperature detection sensor. A temperature control unit that controls the heating device so that the temperature detected by the temperature detection sensor falls within the predetermined temperature range before recording information on the medium. Item 11. The information recording device according to any one of Items 7 to 10. 12. A humidity detecting sensor for detecting the humidity of the medium portion or its vicinity heated by the heating device, and a portion of the medium to be heated or its vicinity based on the detection result by the humidity detecting sensor. A humidity control unit that controls the heating device so that the humidity of the medium is within a predetermined humidity range, and after the humidity detected by the humidity detection sensor becomes a humidity within the predetermined humidity range, The information recording apparatus according to any one of claims 7 to 10, wherein information is recorded in the information recording apparatus.