KR100694094B1 - Method and apparatus for improving data signal charateristics of Super-resolution optical information storage medium - Google Patents

Abstract

The present invention discloses a method and apparatus for improving the characteristics of a data signal read out from a super resolution optical recording medium on which macro data having a magnitude less than or equal to the resolution of a reproduction beam is recorded.

The present invention provides an apparatus for improving a reproduction signal of a super resolution optical recording medium including data recorded with a mark having a size less than or equal to a resolution of a reproduction beam, the apparatus comprising: a filtering unit for frequency band separating an RF signal reflected from the optical recording medium and outputted; And an equalizing unit for equalizing the band-separated RF signal to have a gain characteristic separated with respect to resolution.

According to the present invention, it is possible to improve the signal characteristics when reproducing a data signal recorded on an optical recording medium having a super resolution near field structure in which a mark is recorded at a size equal to or less than the resolution by frequency band separating the RF signal.

Super-RENS, optical recording media, EQ

Description

Method and apparatus for improving data signal characteristics of super-resolution optical recording medium

1 is a graph showing a change in amplitude of an RF signal according to a change in mark length in a conventional Blu-ray disc.

2 is a graph showing gain characteristics according to the RF signal frequency of an equalizer used in a conventional optical recording medium reproducing apparatus.

3A and 3B are graphs showing waveforms of RF signals before and after equalization is performed upon reproduction of marks recorded on an optical recording medium having a super-resolution near field structure according to the related art.

4 is an example of an information storage medium having a super-resolution near field structure to which a method for improving signal characteristics of data according to the present invention is applied.

FIG. 5 schematically shows the structure of a recording / reproducing apparatus for an optical recording medium having a super-resolution near field structure according to the present invention. FIG.

6A and 6B are graphs showing changes in amplitude of an RF signal according to mark length during reproduction of an optical recording medium having a super-resolution near field structure to which the present invention is applied.

7 is a block diagram schematically showing the structure of a data signal improving apparatus according to the present invention;

8 is a graph schematically showing gain characteristics of the first and second equalizers according to the present invention;

9A and 9B are graphs illustrating effects of improving data signal characteristics by the data signal characteristic improving apparatus according to the present invention.

10 is a flowchart illustrating a method of improving data signal characteristics of an optical recording medium having a super resolution near field structure according to the present invention.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical recording medium, and more particularly, to improve a characteristic of a data signal read from a super resolution optical recording medium in which data is recorded with a mark having a size less than a resolution limit of a reproduction beam. A method and apparatus are disclosed.

With the spread of the Internet and the development of multimedia, the download and storage of large files are becoming more common, and the demand for new storage media with greater storage capacity is increasing. Since CDs and DVDs, which are currently used as optical recording media, are limited in increasing their storage capacity, development of next generation information storage media based on a new concept technology has been attempted.

The storage capacity of the optical recording medium can be increased by shortening the wavelength of the laser beam or by increasing the numerical aperture (NA) of the objective lens. However, the current technology has a limitation in providing a laser having a short wavelength, and there is a problem that the manufacturing cost increases in order to manufacture an objective lens having a large numerical aperture. In addition, as the numerical aperture of the objective lens increases, the operating distance between the optical pickup and the storage medium becomes shorter, so that the surface of the storage medium is damaged by the collision of the optical pickup and the storage medium, thereby increasing the risk of losing information recorded on the storage medium.

Further, when the wavelength of the light source used for the reproducing apparatus is λ and the numerical aperture of the objective lens is NA, λ / 4NA is the resolution limit of the reproducing resolution. Therefore, even if it is possible to form the recording mark extremely small, reproduction may not be possible. That is, conventionally, since light irradiated from a light source cannot distinguish a recording mark having a size smaller than λ / 4NA, information reproduction is impossible.

Recently, in order to overcome the limitation of the reproduction resolution, an optical recording medium having a super-resolution near-field structure (Super-RENS) has been studied. Since the optical recording medium having a super resolution near field structure can be reproduced even for a recording mark having a size exceeding the resolution limit, the optical recording medium having a super resolution near field structure can meet the demand of high density and high capacity drastically.

In order to commercialize such an optical resolution medium having a super-resolution near field structure, it is necessary to satisfy recording and reproduction characteristics which are basically required as an information storage medium. There are many basic recording and reproducing characteristics, but the most important one is securing signal-to-noise ratio (hereinafter referred to as C / N) characteristics. In particular, the C / N characteristic is more important because the information storage medium having a super resolution near field structure uses a relatively high power recording beam and a reproduction beam compared to a general information storage medium.

On the other hand, marks are formed on the information recording surface of the optical recording medium having the super-resolution near field structure. The reproduction apparatus reads the marks and decodes them to reproduce the data. The reproducing apparatus irradiates a laser beam to the optical recording medium and measures the intensity of the reflected beam by the mark with a photodetector.

Specifically, where the mark is formed, the reflectance is low and the amount of reflected light is lowered. In the place where the mark is not formed, the reflector has a high reflectance and the amount of reflected light is large. The signal output by the measurement of the reflected beam is called an RF signal. In addition, as the length of the mark decreases, the frequency of the RF signal increases, and as the length of the mark increases, the frequency of the RF signal decreases.

In addition, the amplitude of the RF signal varies depending on the length of the mark. Therefore, in order to effectively process the reproduction signal, equalizing is performed in consideration of the amplitude characteristics of the RF signal for each frequency of the optical recording medium and the like so that the amplitude of the RF signal has a certain level or more.

1 is a graph showing a change in amplitude of an RF signal according to a change in mark length in a Blu-ray disc, which is a conventional phase change disk, and FIG. 2 is an equalizer used in a conventional optical recording medium reproducing apparatus. It is a graph showing gain characteristics according to RF signal frequency.

In Fig. 1, after recording a single mark of 2T to 8T as an optimal recording condition on a 25-gigabyte Blu-ray disc, the amplitude of the RF signal for each mark length according to the frequency is measured before performing equalization.

Referring to FIG. 1, as the mark length increases from 2T to 8T, the amplitude of the RF signal increases and saturates above a certain mark length. Accordingly, in the conventional apparatus for reproducing an optical recording medium, 2T having the smallest amplitude as shown in FIG. 2 so that the RF signal for each frequency may be a constant signal of a predetermined magnitude or more in consideration of the amplitude characteristics of the RF signal for each frequency. At 16.6 MHz, the gain is maximized, and an equalizer (EQ) is used where the gain decreases as the frequency decreases, i.e. as the mark length increases.

However, the optical recording medium of the super-resolution near field structure has substantially the same amplitude for a mark having a resolution lower than that of a conventional Blu-ray disc, unlike a conventional Blu-ray disc. It is known that the amplitude of the RF signal with respect to the short T mark is rapidly reduced.

3A and 3B are graphs showing waveforms of RF signals before and after equalization is performed during reproduction of marks recorded on an optical recording medium having a super-resolution near field structure using an equalizer according to the related art.

3A is a graph of adjusting the gain of an equalizer so that the amplitude of the 2T signal is optimal, and FIG. 3B is a case of adjusting the gain of the equalizer so that the amplitude of the long T signal is optimized. Is a graph.

Referring to FIG. 3A, when the gain of this equalizer is adjusted so that the amplitude of the RF signal A by the T mark is optimal, the peak portion of the RF signal B by the long T mark is distorted. It can be seen that this occurs.

3B, when the gain of the equalizer is adjusted so that the RF signal B 'by the long T-length mark is optimal without distortion, the RF signal A' by the T mark is short. There is a problem that is not sufficiently amplified as necessary for signal reproduction.

Therefore, the conventional equalizer is unsuitable for application to the reproduction of the optical recording medium having the super resolution near field structure, and a new structure equalizer is required to improve the data signal characteristics of the optical recording medium having the super resolution near field structure.

Accordingly, an object of the present invention is to provide a method and apparatus for improving data signal characteristics of an optical recording medium having a super-resolution near field structure.

In addition, the present invention is a method that can improve the data signal characteristics of the optical recording medium by applying an equalizer separated for each frequency band in consideration of the amplitude characteristics of the RF signal according to the mark length of the optical recording medium of the super-resolution near-field structure And an apparatus thereof.

In order to solve the above technical problem, a reproduction signal improving apparatus of the present invention is a reproduction signal improving apparatus for a super resolution optical recording medium including data recorded with a mark having a size equal to or less than a resolution of a reproduction beam, wherein the optical recording medium A filter for frequency band separating the RF signal reflected from the output band; And an equalizing unit for equalizing the band-separated RF signal to have a gain characteristic separated with respect to resolution.

A reproducing apparatus according to the present invention is a reproducing apparatus of a super resolution optical recording medium including data recorded with a mark having a size equal to or less than a resolution of a reproducing beam, wherein the beam is reflected after irradiating the reproducing beam to the optical recording medium. Pick-up unit; And a signal processor for separating the RF signal detected by the pickup unit for each frequency band and performing equalization with a gain characteristic separated with respect to resolution.

A method of improving data signal characteristics according to the present invention is a method of improving data signal characteristics of a super resolution optical recording medium comprising data recorded with a mark having a size less than or equal to the resolution of a reproduction beam. Dividing the RF signal output by the frequency band after the irradiation; And performing equalization with respect to the frequency band separated RF signal to have a separated gain characteristic.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

4 shows an example of an information storage medium having a super-resolution near field structure to which the method for improving signal characteristics of data according to the present invention is applied.

The information storage medium includes a substrate 100, a first dielectric layer 105, a super resolution layer 110, a second dielectric layer 115, a recording layer 120, and a first stacked layer sequentially stacked on the substrate 100. Three dielectric layers 125.

The substrate 100 is formed of any one material selected from polycarbonate, polymethylmethacrylate (PMMA), amorphous polyolefin (APO), and glass materials.

The first to third dielectric layers 105, 115, and 125 are layers for controlling changes in optical and / or thermal characteristics of the super resolution layer 110 or the recording layer 120. The first to third dielectric layers 105, 115, and 125 are not essential components, and information can be reproduced even in the absence of the dielectric layers.

The first to third dielectric layers 105, 115, and 125 are preferably made of at least one of an oxide, a nitride, a carbide, a sulfide, and a fluoride.

The recording layer 120 may be formed of a metal oxide or a high molecular compound. For example, the recording layer 120 may be made of at least one of metal oxides selected from PtOx, PdOx, AuOx, and AuOx. In addition, C ₃₂ H ₁₈ N ₈ , H ₂ PC (Phthalocyanine) may be used as the polymer compound.

The super-resolution layer 110 is an area where a super resolution phenomenon occurs in which thermal or optical characteristics change depending on a temperature distribution due to a partial light intensity difference in a spot generated by irradiation of a reproduction beam. The branch makes it possible to reproduce information with respect to the recording mark m.

Specifically, melting occurs in the super resolution region of the reproduction beam spot, while melting around the super resolution region does not occur, resulting in a difference in refractive index. Due to such a difference in refractive index, it is possible to reproduce the recording mark m having a resolution or less.

Accordingly, the super resolution layer 110 uses a regeneration beam of power having a temperature distribution above the melting point in a portion of the regeneration beam spot. Here, when the reproduction beam of power having a temperature distribution above the melting point of the super-resolution layer 110 is irradiated, the super-resolution layer 110 is the recording so that the recording beam does not affect the recording layer 120. It is preferably made of a material having a melting temperature lower than the thermal decomposition temperature of layer 120. For example, the super resolution layer 110 may be formed of a Ge-Sb-Te-based alloy or an Ag-In-Sb-Te-based alloy.

The reproduction beam for reproducing the mark m recorded in the recording layer 120 may be irradiated from the lower end of the substrate 100 or irradiated from the upper end of the third dielectric layer 125.

Here, the case where the recording layer 120 is positioned above the super resolution layer 110 has been described, but the upper and lower positions of the recording layer 120 and the super resolution layer 110 may be changed. In addition, when the reproduction beam is irradiated from the upper end of the third dielectric layer 125, a cover layer (not shown) may be further provided.

In addition, although one super resolution layer 110 is illustrated in FIG. 4, the super resolution layer may be further provided to improve characteristics of a reproduction signal.

Fig. 5 schematically shows the structure of an apparatus for recording data on and reproducing the recorded data on the optical recording medium having the super-resolution near field structure.

Referring to FIG. 5, a recording / reproducing apparatus of an ultra-resolution near field structured optical recording medium includes a pickup unit 200, a recording / reproducing signal processor 300, and a controller 400.

The pickup unit 200 is a portion for detecting a beam reflected after irradiating a reproduction beam to the optical recording medium (D), the recording / reproduction signal processing unit 300 is to transmit the light detected by the pickup unit 200 After converting the signal to a predetermined signal processing, the control unit 400 controls the operation of each component of the recording / reproducing apparatus.

Specifically, the pickup unit 200 is a laser diode 210 for irradiating a reproduction beam, a collimating lens 220 for parallelizing the light emitted from the laser diode 210, the conversion path of the incident light The beam splitter 230 and the objective lens 240 for focusing the light passing through the beam splitter 230 to the optical recording medium (D).

The recording / reproducing signal processor 300 may include a photodetector 310, a photodetector 310 that detects light that is reflected from the optical recording medium D, and whose propagation path is converted by the beam splitter 230. And a calculation circuit unit 320 for converting the light received by the photodetector 310 into an electrical signal and outputting an RF signal, and a signal processing unit 330 for performing predetermined signal processing to improve characteristics of the RF signal. .

The RF signal output from the signal processor 330 is output to channel 1 ch1 detected as a sum signal and a differential signal channel ch2 detecting a signal by a push-pull method.

The controller 400 controls the reproduction unit 200 to irradiate a reproduction beam having a predetermined power or more required according to the material characteristics of the optical recording medium in order to reproduce a mark having a size smaller than the resolution.

6A and 6B are graphs showing changes in amplitude of an RF signal according to a mark length during reproduction of an optical recording medium having a super-resolution near field structure to which the present invention is applied.

FIG. 6A shows the results of measuring the amplitude change of the RF signal according to the mark length using an optical recording medium having a 50GB super resolution near field structure, and FIG. 6B using an optical recording medium having a 100 GB super resolution near field structure. Here, the reproduction beam used a laser having a size of 3mW.

Referring to FIG. 6A, in a 50GB optical resolution medium having a resolution of between 3T and 4T, the RF signal according to the amplitude change of the RF signal according to the mark length of 3T or less and the mark length of 4T or more. It can be seen that the amplitude change is significantly different. In contrast, the RF signal according to the mark length larger than the resolution exhibits a linear increasing characteristic, whereas the RF signal according to the mark length smaller than the resolution has almost the same value without changing the amplitude. Also, an RF signal with a mark length below resolution has a significantly smaller amplitude than an RF signal with a mark length above resolution. According to the graph shown in FIG. 6A, the amplitude of the RF signal by the 2T mark is only about 1.69% of the amplitude of the RF signal by the 8T.

Referring to FIG. 6B, in the case of the optical recording medium having a 100GB class super-resolution near field structure having a resolution slightly smaller than that of the 7T mark, the amplitude of the RF signal according to the mark length of 7T or less smaller than the resolution is almost the same value without large change. Has However, the RF signal along the mark length larger than the resolution of 8T or more greatly increases, and has a value significantly larger than the value by the marks below the resolution.

It can also be seen that the amplitude of the RF signal by the mark closest to the resolution among the marks below the resolution is smaller than the amplitude of the RF signal by the next smaller mark. For example, in FIG. 6A, the amplitude of the RF signal by the 3T mark is smaller than the amplitude of the RF signal by the 2T mark, and similarly in FIG. 6B, the amplitude of the RF signal by the 6T mark is in the 5T mark. Smaller than the amplitude occurs.

Accordingly, the present invention considers that a sudden change in the amplitude of the RF signal occurs above and below the resolution in the optical recording medium having the super-resolution near field structure, and performs separate equalization on the RF signal corresponding to the above and below the resolution. Accordingly, the present invention provides a method and apparatus capable of improving the characteristics of a data signal generated during reproduction of an optical recording medium having a super resolution near field structure.

That is, in the data signal improving apparatus and method according to the present invention, the signal processor 330 of the recording / reproducing apparatus shown in FIG. 5 considers the frequency characteristics of the optical recording medium having the super-resolution near field structure, and the equalizer has a frequency band. It is characterized by improving the characteristics of the data signal by designing to have the characteristics having separate gain values.

7 is a block diagram schematically showing the structure of a data signal improving apparatus according to the present invention.

The data signal improving apparatus according to the present invention may be included in the signal processor 330 for improving the characteristic of the signal detected by the pickup unit 200 of FIG. 5.

Referring to FIG. 7, the data signal improving apparatus according to the present invention includes a low pass filter 331, a high pass filter 332, first and second equalizers 333 and 334, a compensator 335, and a multiplexer 336. do.

The optical signal detected by the photodetector 310 of FIG. 5 is converted into an RF signal, which is an electrical signal, by the calculation circuit unit 320 and input to the data signal improving apparatus according to the present invention.

The low pass filter 331 extracts a low frequency signal from an input RF signal. As described above, since the mark length and the frequency of the RF signal are inversely related, the longer the mark length, the lower frequency RF signal is output. Therefore, the low pass filter 331 extracts the signal by the long T mark from the input RF signal.

The high pass filter 332 extracts a high frequency signal from an input RF signal. Similarly, as the mark length is shorter, the frequency of the RF signal increases, so that the high pass filter 332 extracts a signal by a short T mark among the input RF signals.

Specifically, the low pass filter 331 extracts an RF signal of a low frequency band by a mark having a length greater than or equal to resolution, and the high pass filter 332 is an RF of a high frequency band by a mark having a length less than or equal to a resolution. Extract the signal.

For example, in a 50GB super-resolution near field structure, when the wavelength of the reproduction beam is 405 nm and the numerical aperture of the objective lens is 0.85, the resolution is about 120 nm. When the optical recording medium is reproduced at a linear speed of 5 m / s, the frequency of the RF signal by the 2T mark having a length of 75 nm is about 33.3 MHz, and the frequency of the RF signal by the 8T mark is about 8.3 MHz. Therefore, the frequency of the RF signal corresponding to the resolution (120 nm) is approximately 20.8 MHz. In this case, the low pass filter 331 extracts a frequency of 20.8 MHz or less, and the high pass filter 332 is designed to extract a frequency of 20.8 MHz or more. The low pass filter 331 and the high pass filter 332 may be designed with some margin in bandwidth.

The RF signals separated by bands in the low pass filter 331 and the high pass filter 332 are amplified by the first equalizer 333 and the second equalizer 334 having different gain characteristics.

8 is a graph schematically illustrating gain characteristics of the first and second equalizers 333 and 334. In FIG. 8, the x-axis denotes a direction in which the mark length is reduced, that is, a direction in which the frequency of the RF signal is increased, and the y-axis represents a gain of the equalizer.

Referring to FIG. 8, the first equalizer 333 has a gain characteristic (a) having a maximum gain value for the mark length that is greater than the resolution and closest to the resolution. As described above, the RF signal due to the mark length beyond the resolution has a linearly increasing characteristic. Accordingly, the first equalizer 333 has a maximum gain value for the mark length that is larger than the resolution but closest to the resolution, and has a gain characteristic that decreases as the mark length increases.

The second equalizer 334 has a gain characteristic (b) that is smaller than the resolution and the gain value corresponding to the mark length closest to the resolution is equal to or greater than the gain value corresponding to the next smaller mark length. That is, the gain value corresponding to the mark closest to the resolution among the marks below the resolution is equal to or larger than the gain value corresponding to the mark length having a length smaller by one period (T).

More specifically, as mentioned in FIG. 6A, in the optical recording medium having a super-resolution near field structure, the amplitude of the RF signal due to the mark length closest to the resolution among the mark lengths below the resolution is the next smaller mark. It is smaller than the amplitude of the RF signal by length. That is, in the example of FIG. 6A, since the amplitude of the RF signal by the 3T mark is smaller than the amplitude of the RF signal by the 2T mark, the gain value of the equalizer corresponding to the 3T mark is at least equal to or greater than the gain value corresponding to the 2T mark. It is to make it big.

Accordingly, the second equalizer 334 has a gain characteristic whose gain corresponding to the mark closest to the resolution is equal to or greater than the gain for the next smaller mark length.

The data signal characteristic improving apparatus according to the present invention having the above configuration improves the characteristics of the data signal by performing equalization having a separate gain characteristic centering on the resolution.

Referring back to FIG. 7, since a time difference may occur between the RF signals whose amplitudes are adjusted through the first and second equalizers 333 and 334, the compensator 335 may determine the first and second equalizers 333 and 334. Compensate for the time difference between the output signals.

The signal output through the compensator 335 is finally gain-adjusted through the multiplexer 336.

9A and 9B are graphs showing the results of experiments on the improvement effect of the data signal characteristic by the data signal characteristic improving apparatus according to the present invention.

FIG. 9A shows jitter of an RF signal measured by recording a 2T (75 nm) mark on a 50GB ultra-resolution near field structure optical recording medium and rotating at a linear speed of 2.5 m / s. FIG. 9B shows 3T (112.5) and the jitter of the RF signal measured by rotating at a linear velocity of 3.75 m / s after recording the mark of nm). Here, the linear velocity is increased to 3.75 m / s when measuring the jitter of the 3T mark so that the gain of the equalizer applied to the RF signal generated by the 3T mark is applied to the gain value of the RF signal (16.6 MHz) by the 2T mark. The experiment was performed to produce an equalizer effect such as gain characteristics according to the present invention.

In other words, the jitter was measured by increasing the linear velocity of the optical recording medium so that the gain value for the 3T mark was equal to the gain of the equalizer applied to the 2T mark.

As a result, referring to FIGS. 9A and 9B, the jitter of the 2T mark represents 17.5%, and the jitter characteristic of the 3T mark is 23.8%, which is the case of using a conventional equalizer, while the present invention is improved to 18.8%. Can be. For reference, if the initial regeneration power is increased from 3.0mW to 3.5mW, the jitter change is approximately 10.93 ~ 11.2%.

10 is a flowchart illustrating a method of improving data signal characteristics of an optical recording medium having a super resolution near field structure according to the present invention.

Referring to FIG. 10, after irradiating a reproduction beam to an optical recording medium having a super-resolution near field structure in order to improve the characteristics of the data signal, the output RF signal is separated according to the mark length (step 500). That is, as mentioned above, the RF signal of the high frequency band by the mark below resolution is separated from the RF signal of the low frequency band by the mark above resolution.

Next, equalization is performed on the frequency band-separated RF signals by using equalizers having separate gain characteristics (step 510).

That is, the first equalizer 333 having a gain characteristic having a maximum gain value with respect to the mark length closest to the resolution larger than the resolution, and a gain value corresponding to the mark length smaller than the resolution and closest to the resolution. Next, separated equalization is performed using the second equalizer 333 having a gain characteristic equal to or greater than a gain value corresponding to the small mark length.

Next, the RF signals amplitude-adjusted by the equalization are respectively compensated for by time difference through a compensator, and are combined by a multiplexer to obtain an RF signal having improved signal characteristics (step 520).

According to the apparatus and method for improving data signal characteristics of an optical recording medium having a super resolution near field structure according to the present invention as described above, optical recording recorded in super resolution by separating the frequency of the RF signal based on the resolution and performing equalization separately Signal characteristics such as jitter characteristics can be improved when the medium is reproduced.

As such, it will be understood by those skilled in the art that the present invention may be implemented in a modified form without departing from the essential features of the present invention. Therefore, the disclosed embodiments should be considered in descriptive sense only and not for purposes of limitation. The scope of the present invention is shown in the claims rather than the foregoing description, and all differences within the scope will be construed as being included in the present invention.

According to the present invention as described above, data signal characteristics including jitter characteristics and the like during reproduction of the data signal of the super-resolution optical recording medium are improved.

Further, according to the present invention, it is possible to improve the signal characteristics at the time of reproducing the data signal recorded on the optical recording medium having a super resolution near field structure in which the mark is recorded at a size less than the resolution by separating the RF signal with the frequency band centered on the resolution .

Claims (11)

An apparatus for improving a reproduction signal of a super resolution optical recording medium comprising data recorded with a mark having a size equal to or less than a resolution of a reproduction beam, A low band filter for extracting a low band RF signal by the mark above the resolution among the RF signals reflected from the optical recording medium, and a high band RF signal by the mark below the resolution among the RF signal. A filtering unit having a band pass filter; And An equalizer having a first equalizer for equalizing the RF signal output from the low band filter and a second equalizer for equalizing the RF signal output from the high band filter, The first equalizer and the second equalizer equalize the low band RF signal due to the mark above the resolution and the high band RF signal due to the mark below the resolution so as to have gain characteristics separated from each other; . delete The method of claim 1, And the first equalizer has a gain characteristic having a maximum gain value for the mark length that is larger than the resolution and closest to the resolution. The method of claim 1, And the second equalizer has a gain value for the mark closest to the resolution among the marks below the resolution being at least equal to or greater than a gain value for the mark one cycle smaller than the closest mark. The method of claim 1, And a compensator for compensating a time difference between the output signals of the first and second equalizers. A reproducing apparatus for a super resolution optical recording medium comprising data recorded with a mark having a size equal to or less than a resolution of a reproduction beam, A pickup unit which detects a beam reflected after irradiating a reproduction beam to the optical recording medium; And The RF signal detected by the pickup unit is separated into a low band RF signal by a mark of higher resolution and a high band RF signal by a mark of lower resolution, and a low band RF signal and a resolution of a mark of higher resolution. And a signal processing unit for performing equalization in which high-band RF signals by the following marks have gain characteristics separated from each other. A method of improving data signal characteristics of a super resolution optical recording medium comprising data recorded with a mark having a size less than or equal to the resolution of a reproduction beam, Dividing the RF signal output after irradiating a reproduction beam to the optical recording medium into an RF signal of a high frequency band by a mark having a resolution lower than that of the resolution of the reproduction beam, and an RF signal of a low frequency band by a mark of a resolution or higher ; And And equalizing the low-band RF signal by the mark having a resolution greater than or higher and the high-frequency RF signal by the mark having a resolution lower than each other to have gain characteristics separated from each other. delete The method of claim 7, wherein And the gain characteristic has a maximum gain value with respect to the mark length closest to the resolution in the case of a mark having a resolution higher than or equal to the resolution. The method of claim 7, wherein And wherein the gain characteristic is at least equal to or greater than a gain value for a mark that is one cycle smaller than the closest mark in the case of a mark of resolution or less. The method of claim 7, wherein And compensating for a time difference between the frequency band-separated and equalized RF signals.

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