KR100607973B1 - Apparatus for recording data on an optical recording medium - Google Patents

Abstract

A method and apparatus for recording data on an optical record carrier are disclosed.

According to the present invention, an apparatus for recording data on an optical recording medium includes: a recording waveform generator for generating a recording waveform having an erase pattern including multiple pulses; And a pickup unit irradiating light to the optical recording medium to form a mark or form a space according to the generated recording waveform. This suppresses the distortion of the mark shape and at the same time improves the mark shape, thereby improving the recording / reproducing characteristics.

Description

Apparatus for recording data on an optical recording medium {Apparatus for recording data on an optical recording medium}

1A is a reference diagram showing a recording waveform according to a conventional scheme;

1B and 1C are reference diagrams showing the shapes of marks formed on the optical recording medium;

2A and 2B are block diagrams of a recording apparatus according to a preferred embodiment of the present invention;

3A is an embodiment of FIG. 2A, FIG. 3B is an embodiment of FIG. 2B,

4A to 4C are examples of recording waveforms generated by the recording waveform generating circuit 2,

5 is another example of a recording waveform generated by the recording waveform generating circuit 2,

6 is a waveform diagram illustrating four types of erase patterns according to an exemplary embodiment of the present invention;

7 is another examples of (a) LH of FIG.

8 to 10 show the shapes of the marks recorded through the simulation,

11 to 15 are graphs showing characteristics of a DVD-RAM;

16 to 20 are graphs showing characteristics of a DVD-RW;

21A is a graph of nucleation and crystal growth rate according to the temperature of an AgInSbTe recording film, and FIG. 21B is a GeSbTe recording film.

22A and 22B are flowcharts for explaining a recording method according to a preferred embodiment of the present invention.

The present invention relates to a method and apparatus for recording data on an optical record carrier, and more particularly, to a method and apparatus for recording digital data by forming a mark on an optical disk.

Recording data on an optical disc, which is one of the optical record carriers, means that marks are formed on tracks formed on the optical disc. In the case of a read-only disc such as a CD-ROM, a DVD-ROM, or the like, the mark is formed of a pit. In the case of a recordable disc such as a CD-R / RW, DVD-R / RW / RAM, a recording layer is coated with a phase change film that changes crystalline or amorphous depending on temperature, and a mark is formed through the phase change of the phase change film.

In terms of signal detection, a data recording method may be divided into a mark edge recording method and a mark position recording method. According to the mark position recording method, the amplitude of the detected RF signal is changed from positive / negative to negative / positive at the position where the mark is recorded. According to the mark edge recording method, the amplitude of the detected RF signal is changed from positive / negative to negative / positive at both edges of the mark. Therefore, accurately recording the edges of the marks is an important factor in improving the quality of the reproduction signal.

However, in the case of a disk coated with a phase change film, the shape of the disk according to the conventional recording method is observed depending on the length of the mark or the spacing of the marks, that is, the length of the space. It can be seen that appears differently. In other words, the end of the mark is formed larger than the leading edge of the mark, thereby degrading the recording / reproducing characteristic. This is more so because of thermal accumulation when the length of the recording mark is relatively long.

1A is a reference diagram showing a recording waveform according to the conventional method.

Referring to FIG. 1A, various recording waveforms for recording Non Return to Zero Inverted (NRZI) data are shown. The first recording waveform is for the DVD-RAM, and the recording waveforms (b) and (c) are for the DVD-RW. Here, T means a period of the reference clock. According to the mark edge recording method, the high level of NRZI data is recorded as a mark and the low level is formed as a space. The recording waveform used to record the mark is called a recording pattern, and the recording waveform used to form a space (used to erase the mark) is called an erase pattern. Conventional recording waveforms (a), (b) and (c) use multi-pulse as the recording pattern, and adjust the power level of each pulse to four levels of Ppeak, Pb1, Pb2 and Pb3, As described above, the power of the erase pattern is kept constant at a predetermined DC level.

As described above, since the erase pattern included in the conventional recording waveform maintains a constant DC level for a predetermined time, heat of about 0 to 200 ° C. is continuously applied to the corresponding area. Therefore, repeated recording a plurality of times causes a deterioration and distortion in the shape of the mark, which leads to a problem that the recording / reproducing characteristics are significantly degraded. In particular, as the high density and high speed for recording more data on the disk proceeds, the period T of the reference clock decreases, which is more so in an environment in which thermal interference between pulses constituting the recording waveform becomes large.

1B and 1C show the shape of the mark formed on the optical recording medium.

1B and 1C, a track of an optical recording medium includes grooves and lands. In order to record predetermined information, a process of forming or removing marks on the above grooves or lands is performed. Going through. However, in order to form or remove the above mark, heat is applied using a laser beam, which may cause a phenomenon in which the applied heat affects the adjacent track or another adjacent mark (Thermal Cross). FIG. 1B shows a conventional method of recording predetermined data by forming marks on both grooves and lands. This method is a method in which a thermal cross is easily affected by the heat applied to the adjacent tracks mentioned above. . FIG. 1C is a method used in most optical recording media, in which a mark is formed only on a groove, and thus is hardly affected by a thermal cross applied to an adjacent track. However, even in the case of the method as shown in FIG. 1C, there remains a problem in that excessive heat applied when forming a predetermined mark may affect the mark formed immediately before it.

On the other hand, conventionally, different recording waveforms are used depending on the type of optical disk, in particular, DVD-RAM, DVD-RW, and the like. This is because the characteristics of the recording film are different. The use of different recording waveforms for each disc is a particular problem when manufacturing a multi-drive capable of recording / reproducing discs of all standards. This is because the multi-drive must be able to implement various types of recording waveforms. This leads to an increase in costs.

SUMMARY OF THE INVENTION In order to solve the above problems, an object of the present invention is a method of recording data with a recording waveform which can more suppress the distortion of the shape of the first and the end of the mark and can suppress the deterioration due to repeated recording and To provide a device.

It is another object of the present invention to provide a method and apparatus for recording data in a recording waveform having an erase pattern which can further improve the shape of the mark.

It is still another object of the present invention to provide a method and apparatus for recording data with recording waveforms applicable to discs having recording films of various characteristics.

It is still another object of the present invention to provide a method and apparatus for generating an erase pulse based on information on a pulse erase power level.

It is still another object of the present invention to provide a method and apparatus for uniformly erasing recording marks by adjusting the power level of a predetermined erase pulse.

The object is that according to the present invention, there is provided a method for recording data on an optical recording medium, wherein (b) the upper level comprises a predetermined pulse higher than the erase power Pe level and the lower level below the erase power level. Forming a mark using a recording waveform having an erase pattern or forming a space.

Step (b) is based on Run Length Limited (RLL) (2, 10) and preferably records a first level of predetermined NRZI data as a macro and a second level as a space.

On the other hand, the above object is a method for recording data on an optical recording medium, comprising: (a) generating channel modulated digital data; (b) generating a write waveform comprising an erase pattern comprising a predetermined pulse at a higher level than an erase power (Pe) level and at a lower level below the erase power level; And (c) forming the first level of the digital data into a mark and forming the second level into a space using the generated recording waveform.

In addition, the step (a) further comprises the step of reading the level information of the erase pulse recorded on the optical recording medium, the step (b) is an erase pattern by the erase pulse generated based on the level information The method may include generating a recording waveform including the above, and the step (a) may include receiving level information of an erase pulse from an external source.

Preferably, steps (a), (b) and (c) are based on RLL (2,10) or RLL (1,7).

Most preferably, the power level of the leading pulse of the erase pattern is the low level of the unit pulse train and the power level of the last pulse is the high level, and the power level of the leading pulse of the erase pattern is the high level of the unit pulse train and of the last pulse. The power level is high level, the power level of the head pulse of the erase pattern is low level of the unit pulse string and the power level of the last pulse is low level, or the power level of the head pulse of the erase pattern is high of the unit pulse string. Level and the power level of the last pulse is preferably low level.

Preferably, the ratio of the duration of the high level and the low level of the multi-pulse is 1 to 1 and the duration of the high level is 1/2 of a clock period.

The step (a) is a step of forming a first level of the predetermined NRZI data as a mark, and the step (b) is effective to form a second level of the NRZI data as a space.

The write signal includes a cooling pulse, and the erase pattern includes a portion of the cooling pulse. When the end point of the cooling pulse is less than or equal to 0.5T from the falling edge of the NRZI signal, it is effective to increase the duration of the leading pulse constituting the erase pattern to 0.5T or more.

Preferably, the unit pulse constituting the erase pattern has a high level and a low level adjusted according to the duration of the leading pulse constituting the recording pattern.

More preferably, the recording pattern includes multiple pulses and the recording pattern has at least two power levels.

On the other hand, according to another field of the present invention, the above object is an apparatus for recording data on an optical recording medium, comprising: a recording waveform generating unit for generating a recording waveform having an erase pattern including multi-pulse; And a pick-up section for irradiating light to the optical recording medium to form a mark or to form a space according to the generated recording waveform.

The apparatus further includes a power information management unit that reads pulse level information of an erase pattern recorded on an optical recording medium and provides the recorded waveform generation unit to the record waveform generation unit, wherein the record waveform generation unit is configured to multiply based on the pulse level information of the erase pattern. And a recording waveform having an erase pattern including pulses. The power information manager may receive the erase pattern pulse level information from the outside and provide the erase pattern pulse level information to the recording waveform generator.

The apparatus may further include a channel modulator for channel modulating data provided from the outside to generate NRZI data and output the NRZI data to the recording waveform generator.

The pickup unit includes a motor for rotating the optical recording medium; An optical head for irradiating laser light onto the optical record carrier or receiving laser light reflected from the optical record carrier;

A servo circuit for servo controlling the motor and the optical head; And a laser driving circuit for driving a laser provided in the optical head.

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

2A and 2B are block diagrams of a recording apparatus according to a preferred embodiment of the present invention.

Referring to FIG. 2A, a recording apparatus is an apparatus for recording data by forming a mark or a space on an optical recording medium 200. The pickup apparatus 1, the recording waveform generating unit 2, and the channel modulating unit 3 are provided. ).

The channel modulator 3 modulates data input from the outside into channel bit strings. The recording waveform generating unit 2 is provided with information regarding the channel bit strings and the erase powers Pb1 and Pb2, and generates a recording waveform for recording the channel bit strings. The recording waveform generated according to the present invention includes an erase pattern with erase multi pulses. Detailed description of the recording waveform will be given later. The pickup unit 1 irradiates light to the optical recording medium 1 according to the generated recording waveform to form a mark or a space.

Referring to FIG. 2B, the recording apparatus is an apparatus for recording data by forming a mark or forming a space on the optical recording medium 200. The pickup apparatus 1, the recording waveform generating unit 2, and the channel modulating unit 3 are provided. ) And a power information management unit (4).

The channel modulator 3 modulates data input from the outside into channel bit strings. The power information management section 4 reads or receives information on the erase powers Pb1 and Pb2 from the optical recording medium.

Performing a recording and erasing test on predetermined test data in a test area of the optical recording medium at predetermined intervals within a predetermined range based on the level information of the erase pulse, and performing the test condition according to the test result. Wherein the best condition is selected from the group and provided to the recording waveform generating unit.

The recording waveform generating unit 2 is provided with information regarding the channel bit strings and the erase powers Pb1 and Pb2, and generates a recording waveform for recording the channel bit strings based on the erase power information. The recording waveform generated according to the present invention includes an erase pattern with erase multi pulses. Detailed description of the recording waveform will be given later. The pickup unit 1 irradiates light to the optical recording medium 1 according to the generated recording waveform to form a mark or a space.

On the other hand, the power information management unit 4 is based on the information about the erase power Pb1 and Pb2 obtained above, within a predetermined range (for example, ± 20% range) of a predetermined value (for example, 3 of the above level value). Write and erase tests on predetermined test data (any data or predetermined data) in the test area of the optical recording medium at intervals of ˜4% value), and according to the test results, A condition (eg, a condition in which the jitter value is minimized, the resolution is the highest, or the modulation degree is the maximum) can be selected and provided to the recording waveform generator.

FIG. 3A is an embodiment of FIG. 2B, and FIG. 3B is an embodiment of FIG. 2B. However, for the block performing the same function, the same reference numerals as those of FIG. 2A or FIG. 2B are given, and repeated descriptions thereof will be omitted.

Referring to Fig. 3A, the recording apparatus includes a pickup section 1, a recording waveform generating circuit 2 and a channel modulator 3. The pickup unit 1 includes a motor 11 for rotating the optical disk 200, an optical head 13 for irradiating laser light to the optical disk 200 or receiving laser light reflected from the optical disk 200. ), A servo circuit 12 for servo control of the motor 1 and the optical head 13, and a laser driving circuit 14 for driving a laser (not shown) provided in the optical head 13.

The channel modulator 3 outputs NRZI (Non Return to Zero Inverted) data by modulating the input data into a channel bit string. The recording waveform generating circuit 2 generates a recording waveform for recording the NRZI data based on the information on the erase power, and provides the recording waveform to the laser driving circuit 14 provided in the pickup section 1.

The laser drive circuit 14 forms a mark or a space on the optical disk 200 by controlling the laser using the received recording waveform.

Referring to FIG. 3B, the recording apparatus includes a pickup section 1, a recording waveform generating circuit 2, a channel modulator 3 and a power information management section 4. As shown in FIG. The pickup unit 1 includes a motor 11 for rotating the optical disk 200, an optical head 13 for irradiating laser light to the optical disk 200 or receiving laser light reflected from the optical disk 200. ), A servo circuit 12 for servo control of the motor 11 and the optical head 13, and a laser drive circuit 14 for driving a laser (not shown) provided in the optical head 13.

The channel modulator 3 outputs NRZI (Non Return to Zero Inverted) data by modulating the input data into a channel bit string. The power information management unit 4 reads out information on the erase powers Pb1 and Pb2 recorded on the optical recording medium, or receives information on the erase power from the outside. The recording waveform generating circuit 2 generates a recording waveform for recording the NRZI data based on the information on the erase power, and provides the recording waveform to the laser driving circuit 14 provided in the pickup section 1.

The laser drive circuit 14 forms a mark or a space on the optical disk 200 by controlling the laser using the received recording waveform.

4A to 4C are examples of recording waveforms generated by the recording waveform generating circuit 2, and FIG. 4A shows pulses required when recording marks for N reference clock lengths, which are arbitrary numbers of integers 2 to 14. FIG. N-2 pieces were used, and an example of using N-1 pieces of pulses required when generating a space for erasing an existing mark during an arbitrary number of N reference clock lengths. In addition, FIG. 4B illustrates that N-1 pulses required for recording marks during N reference clock lengths T, which is an arbitrary number from 2 to 14, are used. In the case of generating a space for erasing the signal, N-1 pulses are used to make the end position of the first pulse of the recording pulse coincide with the end of the first clock pulse. N-1 pulses required for recording marks during N reference clock lengths (T), which is an arbitrary number of integers, were used, and a space for erasing existing marks during any number of N reference clock lengths (Space) For example, N-2 pulses are used to ensure that the end position of the first pulse of the recording pulse coincides with the end of the second clock pulse and the last pulse of the recording pulse coincides with the end of the NRZI. Bo And there.

Referring again to FIG. 4A, the NRZI data depends on the modulation scheme of the channel modulator 3. That is, when modulating with the Run Length Limited (RLL) (2,10) series, that is, the minimum mark according to EFM (Eight to fourteen Modulation), EFM + (Eight to fourteen Modulation plus), D (8-15) and Dual modulation The length is 3T and the maximum mark length is 11T. Here, D (8-15) refers to a modulation scheme published by ODS (Optical Data Storage) in 2001 in "Optical Disc Recording System of 25GB Capacity." Dual modulation is filed by the applicant on September 30, 1999 and published on November 25, 2000, Korean Patent Application No. 99-42032 "RLL code placement method, modulation and demodulation method and demodulation method with improved DC suppression capability. Device ". When recording using the RLL (1,7) series, the minimum recording mark is 2T and the maximum recording mark is 8T.

When the high level of the NRZI data is formed as a mark and the low level is formed as a space, the recording waveform has a recording pattern for recording a mark having a length of 7T, an erase pattern for forming a space having a length of 3T, and a length of 3T. And a recording pattern for recording the mark.

The recording pattern is composed of pulse trains. The erase pattern is also composed of pulse trains, as shown in section F. FIG. Tmp indicates the width of the multi pulses constituting the recording pattern. Here, the multi-pulse refers to at least one pulse having the same width and the magnitude of the power. In this embodiment, Tmp is 0.5T. Tlp indicates the width of the last pulse constituting the recording pattern. Tcl refers to the duration of the cooling pulse. Cooling pulses exist over the write pattern and the erase pattern. Temp refers to the width of an erase multi pulse constituting the erase pattern. In this embodiment, Temp is 0.5T. Tsfp means the time from the point at which the NRZI data is switched from the low level to the high level until the start of the first pulse constituting the recording pattern. Tsfp affects the power level of the erase pattern. That is, as shown, when Tsfp is larger than 0.5T, when the multi-pulse included in the erase pattern ends at the low level Pb1, the subsequent Tsfp starts at the high level Pb2 of the multi-pulse. In contrast, when Tsfp is less than 0.5T, when the multi-pulse included in the erase pattern ends at the low level Pb1, the subsequent Tsfp continues to maintain the low-level Pb1 of the multi-pulse.

Referring to FIG. 4B, when the high level of the NRZI data of FIG. 4B is formed as a mark and the low level is formed as a space, a recording waveform is used to form a recording pattern for recording a mark having a length of 7T, and a space having a length of 3T. The first example of the erasing pattern and the recording pattern for recording the mark having the length of 2T, and the recording waveform to record the mark having the length of 7T when forming the high level of the NRZI data into the mark and the low level into the space And a second example of a recording pattern for forming a space having a length of 5T, a recording pattern for recording a mark having a length of 2T, and the number of pulses of the recording mark portion as shown in FIG. 4A. One more than yes.

Referring to FIG. 4C, when the high level of the NRZI data of FIG. 4C is formed as a mark and the low level is formed as a space, the recording waveform forms a recording pattern for recording a mark having a length of 7T, and a space having a length of 3T. The first example of the erasing pattern and the recording pattern for recording the mark having the length of 2T, and the recording waveform to record the mark having the length of 7T when forming the high level of the NRZI data into the mark and the low level into the space And a second example of a recording pattern for forming a space having a length of 5T, a recording pattern for recording a mark having a length of 2T, and the number of pulses of the recording mark portion as shown in FIG. 4A. One more than the example and one fewer pulses in the space mark portion than the example of FIG. 4A above.

5 is another example of the recording waveform generated by the recording waveform generating circuit 2.

Referring to Fig. 5, when the high level of the NRZI data is formed as a mark and the low level is formed as a space, the recording waveform is a recording pattern for recording a mark having a length of 7T and an erase for forming a space having a length of 5T. A recording pattern for recording a pattern and a mark having a length of 3T.

Similarly, the recording pattern is composed of pulse trains. The erase pattern is also composed of pulse trains, as shown in section G. FIG. Tmp indicates the width of the multi pulses constituting the recording pattern. Multi-pulse refers to at least one pulse of the same width and power magnitude. In this embodiment, Tmp is 0.5T. Tlp indicates the width of the last pulse constituting the recording pattern. Tcl indicates the duration of the cooling pulse. Cooling pulses exist over the write pattern and the erase pattern. Temp refers to the width of an erase multi pulse constituting the erase pattern. In this embodiment, Temp is 0.5T. Tsfp means the time from the point at which the NRZI data is switched from the low level to the high level until the start of the first pulse constituting the recording pattern. Tsfp affects the power level of the erase pattern. That is, as shown, when Tsfp is larger than 0.5T, when the multi-pulse included in the erase pattern ends at the low level Pb1, the subsequent Tsfp starts at the high level Pb2 of the multi-pulse. In contrast, when Tsfp is less than 0.5T, when the multi-pulse included in the erase pattern ends at the low level Pb1, the subsequent Tsfp continues to maintain the low-level Pb1 of the multi-pulse.

6 is a waveform diagram illustrating four types of erase patterns according to an exemplary embodiment of the present invention.

Referring to Figure 6, the erase pattern according to the present invention is classified into four types: (a) LH, (b) HH, (c) HL and (d) LL. Circles are indicated to facilitate differentiation between the erase patterns. First, (a) LH is equal to the low level Pb1 of the erase multi-pulse following the power of the leading pulse constituting the erase pattern, and the last erase multi-pulse constituting the erase pattern ends at the low level Pb1, and then the power level of the subsequent Tsfp is It is the same as the high level Pb2 of the erase multi-pulse. (b) HH is equal to the high level Pb2 of the erase multi-pulse followed by the power of the leading pulse constituting the erase pattern, and the level of Tsfp followed by the last erase multi-pulse constituting the erase pattern ends at the high-level Pb2. It is when the high level of Pb2 lasts. (c) HL is equal to the high level Pb2 of the erased multi-pulse following the power of the leading pulse constituting the erase pattern, and the level of Tsfp followed by the last erased multi-pulse constituting the erase pattern ends at the high-level Pb2. It is equal to the low level of Pb1. Finally, (d) LL is equal to the low level Pb1 of the erase multi-pulse followed by the power of the leading pulse constituting the erase pattern, and the level of Tsfp following the last erase multi-pulse constituting the erase pattern ends at low level Pb1. This is when the low level Pb1 of the erase multi-pulse is continued.

On the other hand, in the embodiments of the recording waveforms of FIGS. 4A to 6 above, although the level of Tcl of the last pulse of the recording waveform is shown to be the same as the lower level of the recording pulse, the level value of Tcl is the above recording pulse if necessary. It may have any one of the intermediate value of the level value between the low level of the and the low level of the erase pulse.

7 is another examples of (a) LH of FIG. 6.

Referring to FIG. 7, (e) LH2 is the same as (a) LH of FIG. 6, but the values of the duration Temp1 of the high level Pb2 of the erase multi-pulse constituting one cycle and the duration Temp2 of the low level Pb1 are 0.7, respectively. Different from T and 0.3T. (f) LH3 is also the same as LH in FIG. 6, but the duration Temp of the high level Pb2 and the low level Pb1 of the erase multi-pulse is 1.0T. Here, the ratio of the duration Temp1 of the high level Pb2 of the erase multi-pulse constituting one cycle to the duration Temp2 of the low level Pb1 can be variously changed to m: n (m, n is an integer).

As described above, the recording waveform according to the present invention has an erase pattern including the erase multi-pulse whose power has a low level Pb1 and a high level Pb2, thereby reducing distortion at the end of the mark and improving reproduction characteristics. In particular, the recording waveforms shown in the above embodiments are suitable for the thermal characteristics of the disk 200 by adjusting the durations of the low level Pb1 and the high level Pb2 of the erase multi-pulse within the range of 0.25 to 0.75T with respect to the clock period T. This is even more so because the duration was chosen and configured.

On the other hand, the information about the four types of erase patterns (type information or erase pulse level Pb1 and Pb2 information) is recorded in the lead-in area of the recordable disc or as one of the header information in the wobble signal. Can be loaded. Therefore, when recording data, the recording apparatus reads the type information or the level information of the erase pulse from the lead-in area or the wobble signal to generate the corresponding recording waveform to form marks and spaces.

Furthermore, the four types of erase patterns can be used as symbols indicating the speed of the disc or the type of the mark in recording and reproducing. For example, it is possible to display information that " a disc using an LH type erase pattern has a double speed of 20 ".

In order to optimize the recording conditions for the four types of erase patterns, the level of the above erase pulses is set within a predetermined range (for example, ± 20%) in a predetermined test area of the disc. For example, recording and playback can be performed every 3 to 4% of the erase pulse level to obtain an optimized recording and playback condition, and the corresponding recording waveform can be generated from this result to form marks and spaces. At this time, there are various ways to determine the optimal recording condition. First, there is a method of measuring jitter and selecting a condition in which the jitter value is the minimum among the test conditions. There may be a way to select the condition that the bit error rate is the minimum by measuring the bit error rate. Third, the resolution (the value of the shortest signal divided by the longest signal amplitude) There is a method of deriving the largest recording condition. Fourth, a method of deriving the maximum recording condition by measuring modulation (the value of the long level signal divided by the low level value of the longest signal). Fifth, there may be a method of deriving the recording conditions within the standard determined by measuring asymmetry. As a test method, a random pattern may be used, and a predetermined pattern may be used.

In order to examine the effect of the present invention, the shape of the recorded mark was observed through simulation. The structure used for the simulation is shown in the following [Table 1]. The disk used has a four-layer film structure.

Board Dielectric film Recording film Dielectric film Reflector Material PC ZnS-SiO2 Sb-Te eutectic ZnS-SiO2 Ag alloy thickness 0.6 mm 128 nm 14 nm 16 nm 30 nm

Simulation conditions were set to wavelength 405nm, numerical aperture NA 0.65, and linear velocity 6m / s. In order to observe the mark shape, the 8T mark was recorded again after the 8T mark was recorded so that 4T overlapped. 8 to 10 show the results of comparing mark shapes in the case of using the conventional recording waveform and in the case of using the recording waveform according to the present invention. FIG. 8A shows a mark formed by simulation, (b) shows a mark formed by the recording waveform according to the present invention, and (c) shows a mark formed by the recording waveform according to the prior art. Similarly, Fig. 9 (d) shows a mark formed by simulation, (e) shows a mark formed by a recording waveform having an erase pattern according to the present invention, and (f) shows a record having a conventional DC erase pattern. The mark formed by the waveform is shown. Fig. 10 (g) shows a mark formed by the simulation, (h) shows after the mark of (g) is erased with the erase pattern according to the present invention, and (i) shows the mark of (g) according to the prior art. It shows after erasing by DC erasure pattern.

[Table 2] shows the parameters of the thin film used in the simulation for thermal analysis.

Material λ = 405 nm C (J / cm ³ K) k (W / cmK) n k ZnS-SiO2 2.300 0.000 2.055 0.0058 Sb-Te eutectic (crystal) 1.650 3.150 1.285 0.0060 Sb-Te eutectic (amorphous) 2.900 2.950 1.285 0.0060 Ag alloy 0.170 2.070 2.450 0.2000

Referring back to the simulation results of FIGS. 8 to 10, the erase pattern according to the present invention of (b) compared to the end of the mark formed by the recording waveform having the conventional DC erase pattern of the conventional scheme of FIG. It can be seen that those of marks formed by recording waveforms having a better quality are better. It can be seen that the shape of the first part of the mark is better by using the erasure pattern according to the present invention as in the end part as shown in FIG. 9. From the above simulation results, it was confirmed that the shape of the mark is improved compared with the conventional one by using a recording waveform having an erase pattern composed of erase multi-pulses according to the present invention. The shape distortion of the mark can be further reduced by adjusting the shape, width, and power level of the erase multi-pulse.

To experimentally verify the effects of the present invention, a DVD evaluator with a laser wavelength of 650 nm and a numerical aperture of 0.6 0.6 is used to obtain the recording waveforms shown in FIGS. 4 and 5 on 4.7 GB DVD-RAM and 4.7 GB DVD-RW discs. The parameters, ie duration and power level, were obtained, and then repeated recording / playback characteristics were compared with the conventional method.

11 to 15 are graphs showing characteristics of the DVD-RAM.

11 to 13 show recording characteristic data according to time change such as power and Tsfp in existing DC erasing in a DVD-RAM disc. In FIG. 11, power condition is Pw = as experimental data for DC erasing in FIG. 14.5mW, Pb1 = 6.0mW, Pb2 = 4.5mW, Pb3 = 3.2mW.

Referring to each drawing, FIGS. 11A and 11B show recording powers for a leading edge, a trailing edge, and both edges of a mark in conventional DC erasing. And jitter characteristics according to erase power, respectively.

12 and 13 show the measured results for conventional DC cancellation.

Referring to (a), (b), (c) and 13 (a) and (b) of FIG. 12, Tsfp = 0.5T and 0.4T show the most preferable jitter characteristics for 3T and 4T or more, respectively. Tlp is good at 0.7T, and it can be seen that Tle has no significant difference in properties.

Based on the experimentally obtained parameters as described above, marks were formed from the recording waveforms having the four types of erase patterns described above, and then the characteristics of the formed marks were measured.

Pb(Pb2-Pb1)=2.0mW 이다. 본 발명에서의 Pb1 및 Pb2의 power는 DC 소거시의 기록조건인 Pe 와 다음과 같은 Pc≤Pb1≤Pe, Pe≤Pb2≤Pw 관계를 가지며 Pb1이 Pe 보다 너무 낮은 power 에서는 기록마크가 완전히 지위지지 않으며 Pb2가 너무 높으면 소거 시에 기록마크가 생성되어 재생신호가 나빠지게 된다. 따라서 Pb1은 Pe 에 대하여 0.5*Pe 보다 크고, Pb2는 Pe 에 대하여 1.5*Pe 보다 작은 값으로 하는 것이 바람직하다. FIG. 14 shows the jitter characteristics of the four types of erase patterns shown in FIG. Referring to FIG. 14A, it can be seen that the LH type is the best among the four types. When measuring the recording characteristics according to the method of the present invention of FIG.

Pb (Pb2-Pb1) = 2.0 mW. In the present invention, the power of Pb1 and Pb2 has a relationship between Pe, which is a recording condition during DC erasure, and Pc≤Pb1≤Pe, Pe≤Pb2≤Pw, and the recording mark is not completely held at a power Pb1 lower than Pe. If Pb2 is too high, a recording mark is generated at the time of erasing, and the reproduction signal is worsened. Therefore, Pb1 is preferably larger than 0.5 * Pe for Pe and Pb2 is smaller than 1.5 * Pe for Pe .

Referring to (b) of FIG. 14, the jitter characteristic of the difference ΔPb (Pb2-Pb1) between the high level and the low level of the erase multi-pulse when the erase pattern is erased using the erase pattern composed of the erase multi-pulse according to the present invention is described. You can look. It can be seen that there is no big difference up to 5mW.

Fig. 15 shows the jitter characteristic of the result of repetitive recording / reproducing using a recording pulse having an erase pattern according to the present invention.

Referring to Fig. 15, as can be readily seen, the case of erasing using the erase multi-pulse according to the present invention shows an excellent result, particularly in terms of repeat recording characteristics.

16 to 20 are graphs showing characteristics of the DVD-RW.

16 to 18 are recording characteristic data according to time changes such as power and Tsfp in existing DC erasing in a DVD-RW disc. In FIG. 16, power condition is Pw = 14.0 as experimental data in DC erasing in FIG. It can be seen that mW, Pe = 6.0mW, and Pc = 0.5mW.

(A) and (b) of FIG. 16 show jitter characteristics according to the recording power and the erasing power of the leading edge, trailing edge, and both edges of the mark in the conventional DC erasing, respectively. Indicates.

17 and 18 show the measured results for conventional DC cancellation.

17 and 18, Ttop = 0.3T and 0.05T were most preferable for 3T and 4T or more, respectively. The last pulse constituting the recording pattern, Tlp was good at 0.55T, and Tle was 1.0T and 1.1T. It can be seen that is good.

Based on the experimentally obtained parameters as described above, marks were formed from the recording waveforms having the above four types of erase patterns, and then the reproduction characteristics of the formed marks were measured. The results are as follows.

Pb(Pb2-Pb1)=1.0mW 이다. 본 발명에서의 Pb1 및 Pb2의 power는 DC 소거시의 기록조건인 Pe 와 다음과 같은 Pc≤Pb1≤Pe, Pe≤Pb2≤Pw 관계를 가지며 Pb1이 Pe 보다 너무 낮은 power 에서는 기록마크가 완전히 지위지지 않으며 Pb2 가 너무 높으면 소거 시에 기록마크가 생 성되어 재생신호가 나빠지게 된다. 따라서 Pb1은 Pe 에 대하여 0.7*Pe 보다 크고, Pb2는 Pe 에 대하여 1.3*Pe 보다 작은 값으로 하는 것이 바람직하다.FIG. 19 shows the jitter characteristics of the four types of erase patterns shown in FIG. Referring to FIG. 19, it can be seen that the HH type is the best among the four types. When measuring the recording characteristics according to the method of the present invention of Fig. 19, the power conditions were obtained:

Pb (Pb2-Pb1) = 1.0 mW. In the present invention, the power of Pb1 and Pb2 has a relationship between Pe, which is a recording condition at the time of DC erasing, as follows: In addition, if Pb2 is too high, a recording mark is generated at the time of erasing, and the reproduction signal becomes worse. Therefore, Pb1 is preferably larger than 0.7 * Pe for Pe and Pb2 is smaller than 1.3 * Pe for Pe.

 In addition, when the erase pattern is erased using the erase pattern including the erase multi-pulse according to the present invention, the jitter characteristic may be described with respect to the difference ΔPb (Pb2-Pb1) between the high level and the low level of the erase multi-pulse. Since the characteristic deteriorates rapidly from 3 mW, 1 mW was selected as a condition of the repetitive recording / reproducing experiment.

Fig. 20 shows the jitter characteristic of the result of repeated recording / reproducing using a recording pulse having an erase pattern according to the present invention.

Referring to FIG. 20, as can be readily seen, the case of erasing using the erase multi-pulse according to the present invention shows an excellent result in particular in terms of repeat recording characteristics. However, more than 2000 times, the jitter characteristic deteriorates sharply. From this, it can be seen that the pulse erasing method according to the present invention is advantageous up to 1000 repeated recordings guaranteed by DVD-RW.

On the other hand, the above experiments used the EFM + modulation method because it was in accordance with the DVD format, but other modulation methods commonly used for recording recording marks stably, for example, RLL (1,7), D (8-15) The same result can be obtained by applying Dual modulation.

FIG. 21A is a graph of nucleation and crystal growth rate with respect to the temperature of an AgInSbTe recording film and FIG. 21B is a GeSbTe recording film. As shown in FIGS. 4A to 7, the erase power Pb1 of the erase pattern pulse is generated to be smaller than the erase power Pe, and the erase power Pb2 is generated to be larger than the erase power Pe. Doing. In addition, the information about the erase power Pb1 and Pb2 is recorded on the optical recording medium and can be used as reference information for reading the above Pb1 and Pb2 information from the drive and generating erase pulses. In the case of the recording medium, it can be used as reference information for generating the erase pulse by receiving the information about the above Pb1 and Pb2 from the outside.

Referring to FIG. 21A, in the AgInSbTe recording film mainly used in DVD-RW, the temperature of crystal growth rate and nucleation frequency is the same, and when erasing with DC erasing power, erasing is performed by accumulation of heat. The temperature of the portion where erasing is stopped is higher than the starting portion, resulting in a difference in crystal growth, which may deteriorate the quality of the reproduced signal. However, in the method according to the present invention, it is possible to set the pulse erasing power Pb2 and Pb1 in which the crystal growth is maximized. As a result, the erasing of the recording marks is made uniform, thereby reducing the noise, thereby improving the quality of the reproduction signal.

21B, the GeSbTe recording film mainly used in the DVD-RAM has a higher crystal growth rate than the temperature of the nucleation frequency. The high Pb2 (high level) increases the crystal growth rate during overwriting on the existing mark, resulting in good erase (crystallization). Therefore, not only the edge characteristics before and after the recording mark are improved but also the erasing of the recording mark is uniform even when the recording mark is erased, thereby reducing the noise. Can be improved.

A recording method according to a preferred embodiment of the present invention based on the configuration as described above is as follows.

22A and 22B are flowcharts for explaining a recording method according to a preferred embodiment of the present invention.

Referring to FIG. 22A, the recording apparatus receives data from an external source and modulates it to generate NRZI data (step 1801). Next, a write waveform having an erase pattern including an erase multi-pulse is generated (step 1802). Next, a mark or a space is formed on the optical disc 200 using the generated recording waveform (step 1803).

Referring to Fig. 22B, the recording apparatus receives data from outside and modulates the data to generate NRZI data, and obtains information on Pb1 and Pb2 of erase power (step 2201). Next, a recording waveform having an erase pattern is generated based on the information on the erase power (step 2202). Next, a mark or a space is formed on the optical disc 200 using the generated recording waveform (step 2203).

As described above, according to the present invention, a method and apparatus for recording data using a recording waveform which suppresses distortion of the mark shape due to thermal interference and heat accumulation between adjacent marks during recording, and at the same time improves the mark shape. Is provided. As a result, recording / reproducing characteristics are improved.

Claims (6)

An apparatus for recording data on an optical record carrier, A recording waveform generator for generating a recording waveform having an erase pattern including multiple pulses; And And a pickup unit for irradiating light to the optical recording medium to form a mark or forming a space according to the generated recording waveform. The method of claim 1, And a power information manager which reads pulse level information of an erase pattern recorded on the optical recording medium and provides the read waveform to the recording waveform generating unit. And the recording waveform generating unit generates a recording waveform having an erasing pattern including multiple pulses based on the pulse level information of the erasing pattern. delete According to claim 2, wherein the power information management unit Based on the level information of the erase pulse, a recording and erasure test is performed on predetermined test data in a test area of the optical recording medium, and the recording waveform is generated by selecting the best condition among the test conditions according to the test result. And recording data on an optical recording medium. The method of claim 1, And a channel modulator for outputting the NRZI data generated by channel modulating the data provided from the outside to the recording waveform generating unit. The method according to claim 1 or 4, The pickup portion A motor for rotating the optical record carrier; An optical head for irradiating laser light onto the optical record carrier or receiving laser light reflected from the optical record carrier; A servo circuit for servo controlling the motor and the optical head; And And a laser drive circuit for driving a laser provided in said optical head.

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