KR20030033178A - Near field data recording/reading method and thereof device - Google Patents

Abstract

PURPOSE: A near field type method for recording and reproducing information and apparatus thereof are provided to prevent coating materials applied to a surface of a disk from being deposited to a surface of an SIL(Solid Immersion Lens). CONSTITUTION: A control part of an optical oscillating part irradiating light to a recording medium controls the optical oscillating part to have a strength capable of increasing near field light generated from the optical oscillating part into a temperature required for recording and reproducing information at the recording medium. The control part controls the optical oscillating part to have optical oscillating periods shorter than gaps of optical oscillating suspension periods. A light generating part generates a laser beam having the decided light strength during the decided time.

Description

Near field method information recording and reproducing method and apparatus therefor {NEAR FIELD DATA RECORDING / READING METHOD AND THEREOF DEVICE}

The present invention relates to an optical recording / reproducing method and a device thereof, and particularly to a method for reducing the surface temperature of a disk by minimizing a laser output time in a near field method in order to prevent sublimation of a coating material and contaminant contamination of the lens. An information recording / reproducing method and apparatus therefor.

In general, an optical recording medium or a magneto-optical recording medium should have a small bit (or recording mark) size and a narrow track width to have a high density recording capacity. However, since the spot size of light condensed on the recording medium to form a bit in the recording film of the recording medium is limited by the diffraction limit, there is a limit in improving the recording density.

In light of the trend of large-capacity information, a new optical recording / reproducing method is required to overcome the limitations of the existing optical recording / reproducing method, and in recent years, the recording capacity can be dramatically improved in response to such a demand. There is increasing research on near field recording / reproduction using the expected near field.

The principle of near field optical recording and reproduction is as follows. Light that enters the lens at an angle greater than or equal to the critical angle is totally reflected when traveling from a dense refractive index to a small one. At this time, due to total reflection of light, light of very small intensity exists on the surface of the lens, which is called an evanescent wave or dissipation wave. Using this evernet wave, it is possible to achieve high resolution, which is impossible because of the diffraction limit, which is an absolute limit of resolution due to diffraction of light in the far-field. The near field optical recording and reproducing optical system totally reflects light in the lens to generate an Evernet wave on the surface of the lens, and records and plays back by coupling the Evernet wave and the recording medium.

1 is a schematic diagram showing an example of a conventional near field type information recording / reproducing apparatus, and FIG. 2 is a graph showing a temperature change of each layer of a disc during recording using the conventional near field type information recording / reproducing method.

As shown in the drawing, a conventional near field type information recording / reproducing apparatus includes an optical oscillation unit 1 for generating a pulse having an optical oscillation period and an optical oscillation period, a laser diode driver 2 for applying a necessary current; A laser diode 3 for oscillating light having a predetermined pulse and intensity by the light oscillator 1 and the laser diode driver 2, a condenser lens 4 for condensing the light emitted from the laser diode 3, A spectroscope 5 for spectroscopy light, an objective lens 6a for guiding the spectroscopic light to the recording surface of the disk D, and a solid immersion lens (hereinafter referred to as 'SIL') 6b. An air-floating head assembly 6 having a magnetizing coil 6c for magnetizing the recording layer of the disc D is included.

In the figure, 6d, which is not described, is a slider.

The process of recording information in the conventional near field type information recording / reproducing apparatus as described above is as follows.

That is, when the disk D rotates, the slider 6d floats on the surface of the disk D by the flow of air generated on the lower surface of the slider 6d of the head assembly 6, and at the same time, the optical oscillation part 1 As shown by a dotted line in FIG. 3, light having a pulse having the same interval between the light oscillation period and the light pause period generates light having a condenser lens 4, a spectroscope 5, an objective lens 6a, and a SIL ( While heating the surface of the disk D via 6b), while applying a current to the magnetizing coil 6c to magnetize the recording layer of the disk D, the characteristics of the disk D are changed to record information. do.

At this time, the recording layer temperature of the disk D on which light is incident is locally raised to 300 to 400 ° C, and the surface layer temperature of the disk is also raised to about 200 to 300 ° C.

As described above, in the conventional near field type information recording / reproducing method and apparatus, the SIL 6b of the disk D and the head assembly 6 despite the fact that the surface layer temperature of the disk D rises to a high temperature of 300 ° C. or higher at the time of recording. Is placed in the vicinity of only 50 ~ 100nm to the surface of the disk (D) in preparation for the collision with the head 6, the various coating materials are scattered by heat and scattered by heat to the surface of the relatively low temperature SIL (6b) There was a problem of greatly lowering the optical properties of the SIL 6b by vapor deposition.

The present invention has been made in view of the above problems with the conventional near field type information recording / reproducing method and apparatus, and when the light is irradiated to the surface of the disk to record information, the temperature of the surface is below a certain temperature. SUMMARY OF THE INVENTION An object of the present invention is to provide a near field type information recording / reproducing method and apparatus for maintaining the optical properties of a SIL by preventing the coating material from scattering.

1 is a schematic diagram showing an example of a conventional near field type information recording / reproducing apparatus.

Figure 2 is a graph showing the temperature change of each layer of the disk during recording using the conventional near field type information recording / reproducing method and the device.

Figure 3 is a graph showing a comparison between the light pulse and the light intensity to which the present invention near field method information recording / reproducing method and apparatus thereof are compared.

Figure 4 is a graph showing the temperature change of each layer of the disk during recording using the present invention near field method information recording / reproducing method and the device.

** Description of symbols for the main parts of the drawing **

1: optical oscillation unit 2: laser diode driving unit

3: laser diode 4: condensing lens

5: spectroscope 6: head assembly

6a: objective lens 6b: solid emulsion lens

6c: Magnetized coil 6d: Slider

In order to achieve the object of the present invention, in a near field type information recording / reproducing method of recording / reproducing information by injecting near field light onto a recording medium, an optical oscillator for irradiating light onto the recording medium records the information on the recording medium. The present invention provides a near field type information recording / reproducing method, which has an intensity capable of raising near field light to a temperature necessary for reproducing or reproducing, and differently controlling the interval between the light oscillation period and the light resting period.

A near field type information recording / reproducing apparatus for recording / reproducing information by injecting near field light oscillating from a laser diode into a recording medium through an optical oscillation unit and a laser diode driving unit, wherein the optical oscillation unit records or reproduces information on the recording medium. A control unit for controlling the interval between the light oscillation period and the light resting period differently, and a light generation unit generating laser light having a light intensity determined by the control unit for a predetermined time. A near field type information recording / reproducing apparatus is further provided.

Hereinafter, the near field method information recording / reproducing method and apparatus thereof according to the present invention will be described in detail with reference to an embodiment shown in the accompanying drawings.

FIG. 3 is a graph showing the optical pulse and the light intensity to which the present invention near field method information recording / reproducing method and apparatus are compared, and FIG. 4 is a method of recording and using the near field method information recording / reproducing method according to the present invention. This is a graph showing the temperature change of each layer of the disk.

As shown in FIG. 1, the near field type information recording / reproducing method and the apparatus according to the present invention, as shown in FIG. 1, include an optical oscillation unit 1, a laser diode driving unit 2, a laser diode 3, and a condenser lens. (4), an air-floating head assembly 6 having a spectroscope 5, an objective lens 6a, a SIL 6b, and a magnetizing coil 6c.

As shown by the solid line in Fig. 3, the light oscillation unit 1 is formed with a light oscillation period shorter than the interval of the light oscillation period, but the light oscillation period is about 1 to 5 ns (nanoseconds) and the temperature at this time is about 150 to It is about 300 ℃.

Incidentally, the light rest period is a time taken for the light oscillator to remain off until the surface temperature of the disk D is cooled to a temperature before being heated.

On the other hand, the light oscillation unit 1 has an intensity that can raise the temperature of the near-field light to a temperature necessary for recording or reproducing information on the recording medium, and the light generating unit for generating light having a different interval between the light oscillation period and the light rest period (not shown) And an optical oscillation control unit (not shown) made of a digital circuit to control the light generating unit.

In addition, the laser diode driver 2 is configured as a high output driver so that the intensity of the current applied to the laser diode 3 during the light oscillation period is about 1.5 times stronger than that of the conventionally known current.

In the drawings, the same reference numerals are given to the same parts as in the prior art.

The optical recording on the disc using the near field type information recording / reproducing method and apparatus of the present invention as described above is as follows.

That is, when the disk D rotates, the head assembly 6 floats on the surface of the disk by the flow of air, and at the same time, the light oscillation section 1 generates light having a pulse whose light oscillation period is shorter than that of the light rest period. This light heats the surface of the disk D via the condenser lens 4, the spectroscope 5, the objective lens 6a, and the SIL 6b, while simultaneously applying a current to the magnetizing coil 6c. Information is recorded by changing the characteristics of the disk D while magnetizing the recording layer of the disk D. FIG.

At this time, the light oscillator 1 is turned off immediately after the light is irradiated onto the surface of the disk D as described above, and the laser diode driver 2 has a higher power than the normal output unit during the light oscillation period. Current is applied.

As a result, the heating heat generated in the disk D is quickly transferred to the recording layer and the heat absorbing layer therein and exits before being widely spread to the surface layer of the disk D having low thermal conductivity.

In this process, the temperature of the recording layer can maintain the temperature of the disk surface to 150 ° C or lower while maintaining the temperature of 300 ° C or more, which is typically required for recording, as shown in FIG. During the recording operation, it is possible to prevent deposition on the surface of the SIL by scattering while subliming with high heat.

The near field type information recording / reproducing method and apparatus thereof according to the present invention provide a method of increasing the intensity by irradiating the interval of the light oscillation period in which the near field light is irradiated to the recording medium at the time of recording while being shorter than the interval of the light rest period in which the near field light is blocked. While the temperature of the recording layer is increased by the required temperature, the surface temperature is lowered to prevent the various coating materials applied to the disk surface from scattering and being deposited on the SIL surface by sublimation with high heat.

Claims (11)

A near field type information recording / reproducing method for recording / reproducing information by injecting near field light onto a recording medium, The near field light generated by the optical oscillation unit irradiating light onto the recording medium has an intensity that can be raised to a temperature necessary for recording or reproducing information on the recording medium and differently controls the interval between the optical oscillation period and the optical resting period. Near field method information recording / reproducing method. The method of claim 1, And a temperature required for recording or reproducing the information generated by the light oscillation unit is 150 to 300 ° C. The method of claim 1, And the optical oscillator is controlled such that the interval of the optical oscillation period is shorter than the interval of the optical oscillation period. The method of claim 3, And the optical oscillation period is 1 to 5 ns. The method of claim 3, The optical idle period is a time taken for the surface temperature of the recording medium to cool down to a temperature before it is heated. A near field type information recording / reproducing apparatus for recording / reproducing information by injecting near field light onto a recording medium, A light generating unit for generating light having a strength capable of raising the temperature of the near field light to a temperature necessary for recording or reproducing information on a recording medium, and having a difference in the interval between the light oscillation period and the light rest period; and an optical oscillation control unit controlling the light generation unit. Near field type information recording / reproducing apparatus further comprising. The method of claim 6, And the optical oscillation control unit controls the interval of the optical oscillation period of the light oscillated by the optical oscillation unit to be shorter than the interval of the optical oscillation period. The method of claim 7, wherein And the optical oscillation control section controls the optical oscillation period of the light oscillated by the optical oscillation unit to 1 to 5 ns. The method of claim 7, wherein And the optical oscillation control section controls the optical rest period of the light oscillated by the optical oscillation unit to the time it takes to cool to the temperature before the surface temperature of the recording medium is heated. The method of claim 6, And the optical oscillation control unit is a digital circuit. The method of claim 6, And the light generating unit generates near-field light such that the surface temperature of the recording medium is 150 to 300 ° C.