HK1067771B - Apparatus for recording data on optical recording medium - Google Patents

Description

Apparatus for recording data on optical recording medium

The present application is a divisional application filed on the 9 th and 28 th 2002 of the application with the name of 02144455.2 entitled "method and apparatus for recording data on an optical recording medium".

Technical Field

The present invention relates to a method and apparatus for recording data on an optical recording medium, and more particularly, to a method and apparatus in which data is recorded on an optical disc by forming marks (marks) on the optical disc.

Background

Recording data on an optical disc, which is an optical recording medium, means forming marks on tracks formed on the optical disc. On a read-only optical disk such as a read-only optical disk-type memory (CD-ROM) and a read-only digital versatile disk-type memory (DVD-ROM), marks are formed in accordance with pits. In recordable optical discs such as CD-R/RW and DVD-R/RW/RAM, a phase-change film is formed in a recording layer, which can be changed into a crystal phase and an amorphous phase and marks are formed by phase change of the phase-change film.

Methods for recording data may be classified into a mark edge recording method and a mark position recording method. According to the mark position recording method, the sign of the amplitude of a detected Radio Frequency (RF) signal changes from negative to positive or from positive to negative at the position of a recording mark. According to the mark edge recording method, the sign of the amplitude of the detected radio frequency signal changes from negative to positive or from positive to negative at both edges of the mark. And therefore, in terms of improving the quality of a reproduced signal, the edge of a recorded mark is an important factor,

however, in the optical disc on which the phase change film is coated, it is found that the shape of the trailing edge of the mark recorded according to the related art recording method may vary according to the length of the mark or the interval between marks, i.e., the space. That is, the trailing edge of the mark is formed to be larger than the leading edge of the mark, and thus, the recording/reproducing characteristics are deteriorated. If the mark is relatively long, the characteristics will deteriorate even more.

Fig. 1 is a schematic diagram of a reference recording waveform according to the prior art.

Referring to fig. 1, there are shown respective recording waveforms (a), (b), and (c) for recording non-return-to-zero flipped (NRZI) data. The recording waveform (a) is used for DVD-RAM, and the recording waveforms (b) and (c) are used for DVD-RW. Here, T represents the period of the reference clock. According to the mark edge recording method, a high level of NRZI data is recorded as a mark, and a low level of NRZI data is recorded as a space. A recording waveform mark used when recording a mark is referred to as a recording pattern (pattern), and a recording waveform used when forming a gap is referred to as an erasing pattern. The recording waveforms (a), (b) and (c) of the related art use a plurality of pulses for recording, and the power of the erase mode is maintained at a predetermined direct current level, as shown in interval E.

Since the erase mode included in the recording waveform of the related art is maintained at a direct current level for a predetermined time, heat at 0 to 200 c is continuously applied to the corresponding area. Therefore, if recording is repeated a plurality of times, the shape of the mark is deteriorated and distorted, and thus, the recording/reproducing characteristics are deteriorated. In particular, in order to record more data on an optical disc, research and development toward high density and high line speed has made the clock period T shorter, and therefore, thermal interference between pulses forming a recording waveform increases, causing more serious deterioration.

Meanwhile, in the related art, since the characteristics of the recording film are different, different recording waveforms are used according to the kind of optical disc such as DVD-RAM and DVD-RW and the specification, for example. In particular, in practice, different recording waveforms should be used for each type of optical disc, which means that problems are encountered in manufacturing multi-drives that can record/reproduce optical discs of all specifications because the multi-drives are to be adapted to the various recording waveforms. This problem causes an increase in cost.

Disclosure of Invention

In order to solve the above-described problems, a first object of the present invention is to provide a recording method and apparatus in which the shape distortion and deterioration of the leading and trailing edges of a mark due to repeated recording can be prevented.

It is a second object of the present invention to provide a recording method and apparatus in which data is recorded using a recording waveform having an erase pattern capable of improving the shape of a mark.

A second object of the present invention is to provide a recording method and apparatus in which data is recorded using a recording waveform applicable to an optical disc including a recording film having various characteristics.

In order to achieve the above object of the present invention, there is provided a method for recording data on an optical recording medium, which includes forming a mark or a space by using a recording waveform having an erase pattern including a plurality of pulses.

Preferably, data is recorded in Run Length Limited (RLL) (2, 10), a first level of predetermined Non Return to Zero Inverted (NRZI) is recorded as a mark, and a second level of predetermined NRZI is recorded as a gap.

Further, in order to achieve the above object of the present invention, there is provided a method for recording data on an optical recording medium, comprising: (a) generating channel-modulated digital data, (b) generating a recording waveform having an erase pattern and a recording pattern including a plurality of pulses, (c) forming a first level of the digital data as a mark and a second level of the digital data as a gap by using the generated recording waveform.

Preferably, steps (a) to (c) are performed based on Run Length Limited (RLL) (2, 10) or RLL (1, 7).

More preferably, the power level of the leading edge pulse of the erase mode is a low level in the multi-pulse, and the power level of the trailing edge pulse is a high level in the multi-pulse. In addition, the power level of the leading edge pulse of the erase mode is a high level in the multi-pulse, and the power level of the trailing edge pulse is a high level in the multi-pulse. The power level of the leading edge pulse of the erase mode is a low level in the multi-pulse, and the power level of the trailing edge pulse is a low level in the multi-pulse. The power level of the leading edge pulse of the erase mode is a high level in the multi-pulse, and the power level of the trailing edge pulse is a low level in the multi-pulse.

Preferably, the ratio of the duration of the high level to the duration of the low level in the multipulse is substantially 1: 1, and the duration of the high level is 1/2 clock cycles.

Preferably, in the step (a), a first level of NRZI data is formed as a mark, and in the step (b), a second level of NRZI data is formed as a gap.

The recording waveform includes a cooling pulse (cooling pulse), and the erase pattern includes a part of the cooling pulse. Preferably, the duration of the leading edge pulse forming the erase mode is increased more than 0.5T if the termination time of the cooling pulse from the trailing edge of the NRZI signal is less than or greater than 0.5T.

Preferably, the unit pulse composed or included in the multi-pulse has a high level and a low level adjustable by the duration of the leading edge pulse forming the recording pattern.

Preferably, the recording mode has at least two power levels.

Further, in order to achieve the above object of the present invention, there is provided an apparatus for recording data on an optical recording medium, comprising: a recording waveform generating unit that generates a recording waveform having an erase mode and a recording mode including a plurality of pulses; and a pickup unit that irradiates light onto the optical recording medium according to the generated recording waveform so as to form a mark or a space.

Preferably, the apparatus further comprises: and a channel modulation section for performing channel modulation on the data supplied from the outside and outputting the NRZI data thus generated to the recording waveform generation section.

Preferably, the pickup unit includes: a motor for rotating the optical recording medium; an optical read/write head that irradiates light onto an optical recording medium or receives light reflected from the optical recording medium; a servo circuit for controlling the motor and the optical pickup head; and a laser driving circuit that drives a laser device mounted in the optical read/write head.

There is provided an apparatus for alternately forming a first state and a second state on an optical recording medium in response to input data having a first level and a second level, respectively, in an optical recording apparatus, comprising: a recording waveform generating unit that generates a waveform including: a first multi-pulse having a plurality of first pulses corresponding to a first level in the input data; and a second multi-pulse having a plurality of second pulses corresponding to a second level in the input data.

Drawings

The above objects and advantages of the present invention will become more apparent by describing in detail preferred embodiments thereof with reference to the attached drawings, in which:

FIG. 1 is a schematic diagram of a reference recording waveform according to the prior art;

fig. 2 is a block diagram of a recording apparatus according to a preferred embodiment of the present invention;

FIG. 3 is an example of an implementation of the recording apparatus of FIG. 2;

FIG. 4 is an example of a waveform generated by the recording waveform generation circuit;

FIG. 5 is another example of a waveform generated by the recording waveform generation circuit;

FIGS. 6a-6d are 4 types of waveforms for explaining an erase mode according to a preferred embodiment of the present invention;

FIGS. 7e-7f are another example of the LH in FIG. 6 a;

FIGS. 8-10 are shapes of marks recorded in an analog manner;

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

FIGS. 16-20 are graphs showing DVD-RW characteristics;

fig. 21 is a flow chart illustrating a method according to a preferred embodiment of the present invention.

Detailed Description

Fig. 2 is a block diagram of a recording apparatus according to a preferred embodiment of the present invention. Referring to fig. 2, a recording apparatus capable of forming marks on an optical recording medium 200 includes: a pickup unit 1, a recording waveform generation unit 2, and a channel (channel) modulation unit 3.

The channel modulation section 3 modulates data input from the outside into a channel bit stream (bit stream). The recording waveform generation unit 2 receives the channel bit stream and generates a recording waveform for recording the received channel bit stream. The recording waveform generated according to the present invention has an erase pattern containing erase multi-pulses. The waveform will be explained later. The pickup unit 1 irradiates light onto the optical recording medium 1 according to the generated recording waveform so as to form a mark or a space.

Fig. 3 is an example of implementing the recording apparatus in fig. 2. The same components are denoted by the same reference numerals and the same explanation is omitted.

Referring to fig. 3, the recording apparatus includes: a pickup unit 1, a recording waveform generation circuit 2, and a channel modulation unit 3. The pickup unit 1 has a motor for rotating the optical disk 200, an optical read/write head 13 for receiving light reflected from the optical disk 200, a servo circuit 12 for servo control, and a laser drive circuit 14 for driving a laser mounted in the optical read/write head 13.

The channel modulation section 3 modulates data input from the outside into a channel bit stream and outputs NRZI data. The recording waveform generation circuit 2 generates a recording waveform for recording NRZI data and supplies the recording waveform to the laser drive circuit 14.

The laser driving circuit 14 forms a mark or a space by controlling the laser with the received recording waveform.

Fig. 4 is an example of a waveform generated by the recording waveform generation circuit.

Referring to fig. 4, NRZI data varies according to a modulation method of the channel modulation unit 3. That is, if the Modulation method is a Run Length Limited (RLL) cascade (series) method, i.e., according to 8 to 14(EFM) Modulation, 8 to 14(EFM) Modulation positive (EFM +), D (8-15), and double Modulation (Dual Modulation), the minimum mark Length is 3T and the maximum mark Length is 11T. Here, D (8-15) is a method disclosed in "25 GB capacity optical disc recording system" named Matsushita in the optical data storage device (ODS) 2001. The dual modulation is disclosed in korean patent application No. 99-42032, entitled RLL code allocation method, modulation and demodulation method, and demodulation apparatus having improved dc control capability, which was filed by the present applicant at 30/9 in 1999 and disclosed at 25/11 in 2000. If data is recorded using the RLL (1, 7) serialization method, the minimum mark is labeled 2T and the maximum mark is labeled 8T.

When forming a high level recording as a mark and a low level recording as a gap in NRZI data, the recording waveform includes a recording pattern for a 7T-long mark for recording and an erasing pattern for a 3T-long gap for recording and a recording pattern for a 3T-long mark for recording.

The recording pattern consists of a pulse train. The erase pattern is further comprised of a chain of pulses as shown in interval F. Tmp represents the width of the multi-pulse forming the recording pattern. Here, the multi-pulse means at least one pulse having the same width and power. Tlp represents the width of the last pulse forming the recording pattern. Tcp represents the width (duration) of the cooling pulse. The cooling pulse extends from the recording mode to the erasing mode. Temp represents the width of the multiple pulses forming the erase pattern. In this example, Temp is 0.5T. Tsfp represents a period from the instant when NRZI data transitions from a low level to a high level to the instant when the first pulse forming the recording mode starts. Tsfp has an effect on the power level of the erase mode. That is, as shown in fig. 4, if Tsfp is greater than 0.5T and the multi-pulse included in the erase mode is terminated at the low level Pb1, the next Tsfp starts from the high level Pb2 of the multi-pulse. Meanwhile, if Tsfp is less than 0.5T and the multi-pulse included in the erase mode is terminated at the low level Pb1, the next Tsfp sustain multi-pulse low level Pb1 starts.

Fig. 5 is another example of a waveform generated by the recording waveform generation circuit.

Referring to fig. 5, when a high level of NRZI data is formed as a mark and a low level is formed as a space, a recording waveform includes: a recording pattern of marks of 7T length for recording and an erasing pattern for forming gaps of 5T length and a recording pattern of marks of 3T length for recording.

The recording pattern consists of a pulse train. In addition, the additional erase pattern consists of a chain of pulses at intervals G as shown. Tmp represents the width of the multi-pulse forming the recording pattern. Here, the multi-pulse means at least one pulse having the same width and power. In the present invention, Temp is 0.5T. Tlp represents the width of the last pulse forming the recording pattern. Tcp represents the width (duration) of the cooling pulse. The cooling pulse extends from the recording mode to the erasing mode. Temp represents the width of the erase multi-pulse forming the erase pattern. In this example, Temp is 0.5T. Tsfp represents a period from the instant when the NRZI data transits from the low level to the high level to the instant when the first pulse forming the recording pattern starts (first pulse start point). Tsfp has an effect on the power level of the erase mode. That is, as shown in fig. 4, if Tsfp is greater than 0.5T and the multi-pulse included in the erase mode is terminated at the low level Pb1, the next Tsfp starts from the high level Pb2 of the multi-pulse. Meanwhile, if Tsfp is less than 0.5T and the multi-pulse included in the erase mode is terminated at the low level Pb1, the next Tsfp sustain multi-pulse low level Pb1 starts.

Fig. 6a to 6d are 4 types of waveforms for explaining an erase mode according to a preferred embodiment of the present invention.

Referring to fig. 6a-6d, the classification according to the invention is of 4 types: (a) LH, (b) HH, (c) HL and (d) LL. Differences in the circle marker erase pattern are exploited so that these differences can be more easily understood. First, (a) LH represents that the power level of the leading edge pulse of the multi-pulse forming the erase mode is the same as the low level Pb1 of the following erase multi-pulse, and terminates at the low level Pb1 after the last erase multi-pulse forming the erase mode. The power level of the following Tsfp is the same as the high level Pb2 of the erase multi-pulse. (b) HH represents that the power level of the leading edge pulse forming the erase pattern is the same as the high level Pb2 of the following erase multi-pulse and terminates at the high level Pb2 after the last erase multi-pulse forming the erase pattern. The power level of the following Tsfp continues at the high level Pb2 of the erase multi-pulse. (c) HL denotes that the power level of the leading edge pulse of the multipulse forming the erase mode is the same as the high level Pb2 of the following erase multipulse and terminates at the high level Pb2 after the last erase multipulse forming the erase mode. The power level of the following Tsfp is the same as the low level Pb1 of the erase multi-pulse. Finally, (d) LL represents that the power level of the leading edge pulse forming the erase mode is the same as the low level Pb1 of the following erase multi-pulse and terminates at the low level Pb1 after the last erase multi-pulse forming the erase mode. The power level of the following Tsfp continues at the low level Pb1 of the erase multi-pulse.

FIGS. 7e-7f are another example of the LH in FIG. 6 a. Referring to fig. 7e to 7f, except that the duration Temp1 of the high level Pb2 of the erase multi-pulse forming one circle is 0.7T and the duration Temp2 of the low level Pb1 of the erase multi-pulse is 0.3T, (e) LH2 is the same as (a) LH in fig. 6. Further, (f) LH 3 is the same as (a) LH in fig. 6 except that the duration of the high level Pb2 or the duration of the low level Pb1 of the erase multi-pulse is 1.0T. Here, the ratio of Temp1 and Temp2, i.e., the ratio of the duration of the high level Pb2 and the duration of the low level Pb1 of the erase multi-pulse forming one circle, may be varied in m: n in various ways. (where m, n are integers). Therefore, the recording waveform according to the present invention has an erase pattern including erase multi-pulses whose power is a high level Pb2 and a low level Pb1, thereby preventing distortion of the trailing edge of a mark and improving reproduction characteristics. In particular, in the recording waveform shown in the embodiment described above, the duration of the high level Pb2 and the duration of the low level Pb1 in the erase multi-pulse are adjusted in the range between 0.25T to 0.75T of the clock period T, and a duration suitable for the thermal characteristics of the optical disc 200 is selected. Thus further improving the reproduction characteristics.

Meanwhile, information (type information) regarding the 4 types of erase patterns may be recorded in a lead-in area of a recordable optical disc, or may be included in a wobble signal as one of header information items. In this case, when recording data, the recording apparatus reads out type information from the lead-in area or the wobble signal, and forms marks or spaces by generating corresponding waveforms.

Further, when recording data and reproducing data, 4 types of erase patterns can be used as a symbol representing the multiple of the speed of the optical disc or the type of mark. For example, the erasure pattern may represent "the speed of the optical disc is 20 times the speed using the LH type erasure pattern".

To test the effect of the present invention, the shape of the mark recorded in analog form was observed. The structures used in the simulations are listed in table 1. The optical disc used in the simulation had a 4-layer film structure.

TABLE 1

	Substrate	Dielectric film	Recording film	Dielectric film	Reflective film
						Material	PC	ZnS-SiO	Eutectic of Sb-Te	ZnS-SiO	Silver alloy
Thickness of	0.6 mm	128 nm	14 nm	16 nm	30 nm

The conditions simulated included: wavelength 405 nm, Numerical Aperture (NA) 0.65, linear velocity 6 m/s. In order to observe the shape of the mark, after 8T recording marks are recorded, the next 8T recording mark is recorded by overlapping 4T of the previous 8T recording marks. Fig. 8 to 10 show the results of comparison of the mark shape when the recording waveform according to the present invention is used and the mark shape when the recording waveform according to the present invention is used. In fig. 8, (a) shows the result formed by the simulation, (b) shows the mark formed at (a) with the recording waveform according to the present invention, and (c) shows the mark formed at (a) with the recording waveform of the related art. Similarly, (d) in fig. 9 shows the result formed by the simulation, (e) shows the mark formed by the recording waveform having the erase mode according to the present invention, and (f) shows the mark formed by the recording waveform having the dc erase mode according to the related art. In fig. 10, (g) represents the result formed by simulation, (h) represents the result of erasing the mark in (g) using the erase mode according to the present invention, and (i) represents the result of erasing the mark in (g) using the related art direct current erase mode.

Table 2 shows the parameters of these membranes used in the simulation for verification of heat.

TABLE 2

Referring again to the simulation results in fig. 8-10, it is shown that the trailing edge of the mark formed using the recording waveform having the erase pattern according to the present invention shown in fig. 8(b) is better than the trailing edge of the mark formed using the recording waveform having the prior art direct current erase pattern of the prior art method shown in fig. 8 (c). Similar to the trailing edge, the shape of the leading edge of the mark is better when the erase mode according to the present invention is employed, as shown in fig. 9. The results of the simulation show that the shape of the time mark is improved when a recording waveform having an erase pattern formed in multiple pulses is employed, as compared with the prior art. By adjusting the shape, the width and power of the erase multi-pulse, and the distortion of the mark shape can be further reduced.

In order to experimentally verify the effect of the present invention, parameters required in obtaining the recording waveforms as shown in fig. 4 and 5, i.e., duration and power level, were obtained by using a DVD discriminator having a laser wavelength of 650 nm and an NA of 0.60, 4.7GB of DVD-RAM and 4.7GB of DVD-RW. Then, the characteristics of the repetitive recording/reproduction according to the present invention are compared with the prior art.

FIGS. 11 to 15 are graphs showing characteristics of the DVD-RAM. FIGS. 11-13 illustrate characteristics of power and time for recording by using a recording waveform having a prior art DC erase mode; fig. 14-15 show improved features of recording by using the recording waveform of the present invention. In fig. 11, (a) and (b) show jitter characteristics with respect to recording power and erasing power for a leading edge and a trailing edge, respectively, of a mark in a related art direct current erase mode. According to (a) and (b), a recording power of 14.5 milliwatts and an erasing power of 6 milliwatts were selected for the experiments.

Fig. 12-13 show the measurement results in a prior art dc wipe.

Referring to (a), (b), and (c) in fig. 12 and (a) and (b) in fig. 13, they represent the most preferable jitter characteristics when Tsfp is 0.5T and when Tsfp is 0.4T. Tle does not affect the jitter characteristics, and Tlp is good when the period is 0.7T.

From the parameters obtained by the experiment in this manner, marks were formed in accordance with the recording waveform having the 4 types of erase patterns as described above, and the characteristics of the formed marks were measured as follows.

Fig. 14 shows 4 types of jitter characteristics as shown in fig. 6 according to the present invention.

Referring to fig. 14, it can be inferred that the jitter characteristics when recording with the recording waveform of the present invention having the erase mode (i.e., any one of the 4 types shown in fig. 6) are good. In particular, referring to FIG. 14(a), it is shown that LH is the best one of the 4 types. Referring to fig. 14(b), jitter characteristics as a difference Δ Pb (Pb2-Pb1) between the high level and the low level of the erase multi-pulse when the erase mode formed in accordance with the erase multi-pulse according to the present invention is employed in erasing a mark are shown. It shows that there is no large difference up to 5 mw.

Fig. 15 shows jitter characteristics of a result of repeating recording/reproducing by using a recording waveform having an erase pattern according to the present invention, compared with the related art.

Referring to fig. 15, it can be easily understood that the result is good particularly in terms of the corresponding recording characteristics when the marks are erased using the erase mode according to the present invention.

FIGS. 16 to 20 are graphs showing DVD-RW characteristics. Fig. 16 to 18 show characteristics of recording power and time by using a recording waveform according to a related art dc erase mode, and fig. 119 to 20 show improved characteristics by using a recording waveform according to the present invention.

In fig. 16, (a) and (b) show jitter characteristics with respect to recording power and erasing power for leading and trailing edges, respectively, in the leading and trailing edge of a mark in the related art direct current erase. According to (a) and (b), a recording power of 14.0 milliwatts and an erasing power of 6 milliwatts were selected.

Fig. 17 and 18 show measurement results in the prior art direct current erasing.

Referring to fig. 17 and 18, they show the most preferable jitter characteristics when Tsfp is 0.3T and Tsfp is 0.05T. Tle was good at 0.55T, and Tlp was good at 1.0T and 1.1T.

From the parameters obtained by the experiment in this manner, marks were formed in accordance with the recording waveform having the 4 types of erase patterns as described above, and the recording characteristics of the formed marks were measured as follows.

Fig. 19 shows 4 types of jitter characteristics as shown in fig. 6 according to the present invention.

Referring to FIG. 19, it is shown that LH is the best one of the 4 types. When the erase pattern formed in accordance with the erase multi-pulse according to the present invention is employed in erasing a mark, jitter characteristics as a difference Δ Pb (Pb2-Pb1) between the high level and the low level of the erase multi-pulse are expressed. Since this characteristic suddenly deteriorated from 3 mw, 1 mw was selected as a condition for repeating the recording/reproducing experiment.

Fig. 20 shows jitter characteristics of repeated recording/reproducing results using recording pulses having an erase pattern according to the present invention.

Referring to fig. 20, it can be easily understood that the result is good particularly in terms of the corresponding recording characteristics when the marks are erased using the erase mode according to the present invention. However, the jitter characteristics suddenly deteriorated from 2000 times. Therefore, it is shown that the pulse erasing method according to the present invention has an advantage of repeated recording up to 1000 times, which is guaranteed in the general DVD-RW.

Meanwhile, the above experiment follows the format and thus uses the EFM + modulation method. However, if any other commonly used methods such as RLL (1, 7), D (8-15) and double modulation are used, the results will be the same.

A recording method according to a preferred embodiment of the present invention according to the above-described structure will be explained below.

Fig. 21 is a flow chart illustrating a method according to a preferred embodiment of the present invention.

Referring to fig. 21, the recording apparatus receives data from the outside, modulates the data, and generates NRZI data in step 1801. Then, in step 1802, the recording apparatus generates a recording waveform having the erase pattern including the erase multi-pulse. In step 1803, a mark or a gap is formed on the optical disc 200 by using the generated recording waveform.

As described above, according to the present invention, there are provided a method and apparatus for recording data, in which a recording waveform capable of preventing distortion of a mark shape due to thermal influence and heat accumulation when recording data is employed and the shape of a mark is improved, so that recording/reproducing characteristics are improved.

Claims (23)

1. In an optical recording apparatus for alternately forming first and second states on an optical recording medium in response to input data having first and second levels, respectively, comprising:

a recording waveform generating unit that generates a waveform including: a first multi-pulse having a plurality of first pulses corresponding to a first level in the input data; and a second multi-pulse having a plurality of second pulses corresponding to a second level in the input data, wherein a power level of a leading pulse of the second multi-pulse is a high level or a low level of the second multi-pulse, and a power level between an end point of the second multi-pulse and a start point of the leading pulse of the first multi-pulse is the high level or the low level of the second multi-pulse;

and a pickup unit that generates light to form a first state and a second state on the optical recording medium based on the first multi-pulse and the second multi-pulse in the recording waveform generated from the recording waveform generating unit.

2. The apparatus of claim 1, wherein the pickup unit further comprises laser means, the laser means developing a voltage that generates light, and the voltage varying in accordance with the first pulse during the formation of the first state and in accordance with the second pulse during the formation of the second state.

3. The apparatus of claim 2, wherein the voltage is a non-dc voltage.

4. The apparatus of claim 1, wherein inputting data comprises: NRZ I data having a high potential and a low potential representing the first and second levels, respectively.

5. The apparatus of claim 1, wherein the first state is a mark and the second state is a gap.

6. The apparatus of claim 1, wherein the first multi-pulse is a first recording pattern forming a mark, and the second multi-pulse is a second recording pattern forming a gap.

7. The apparatus of claim 1, wherein the recording waveform generating unit generates a cooling pulse extending from a first pulse of the first plurality of pulses to a second pulse of the second plurality of pulses.

8. The apparatus of claim 7, wherein the cooling pulse forms a portion of the first pulse and a portion of the second pulse.

9. The apparatus of claim 1, wherein a first pulse of the first plurality of pulses has a first high level and a first low level; the second pulse of the second plurality of pulses has a second high level and a second low level.

10. The apparatus of claim 9, wherein the high level of the second pulse is less than the high level of the first pulse.

11. The apparatus of claim 9, wherein the first pulse comprises a first start pulse and a first stop pulse, the second pulse comprises a second start pulse and a second stop pulse, and the first start pulse varies according to the second start pulse and the second stop pulse.

12. The device of claim 9, wherein the first pulse has a first duty cycle and the second pulse has a second duty cycle.

13. The apparatus of claim 12, wherein each second pulse comprises a high level and a low level, and the second duty cycle comprises:

the ratio of the duration of the high level to the duration of the low level ranges between 0.25T-0.75T, where T is one period of the reference clock.

14. The apparatus of claim 1, further comprising:

and a servo unit which rotates the optical recording medium according to the first and second multi-pulses during formation of the first and second states.

15. The apparatus of claim 14, wherein the second pulse comprises a second start pulse and a second end pulse; and the servo unit controls the speed of the rotation of the optical recording medium according to one of the second start pulse and the second end pulse.

16. The apparatus according to claim 1, wherein the recording waveform generating unit generates information data representing the characteristics of the second multipulse.

17. The apparatus of claim 16, wherein the information data is recorded as a wobble signal on the optical recording medium.

18. The apparatus of claim 16, further comprising:

and a servo unit that rotates the optical recording medium according to the information data.

19. The apparatus of claim 16, further comprising:

and a laser device for recording information data on the optical recording medium.

20. The apparatus of claim 19, wherein the optical recording medium includes a lead-in area, and the information data is recorded in the lead-in area.

21. The apparatus of claim 19, further comprising:

and a servo unit that reads information data from the optical recording medium and rotates the optical recording medium at a speed corresponding to the information data.

22. The apparatus of claim 19, further comprising:

and a servo unit that rotates the optical recording medium at a first speed, reads information data from the optical recording medium, and rotates the optical recording medium at a second speed according to the information data.

23. In an optical recording apparatus for alternately sequentially forming first and second states on an optical recording medium in response to input data having first and second levels, respectively, comprising:

a recording waveform generating unit that generates a waveform including: a first multi-pulse having a plurality of first pulses corresponding to a first level in input data, a second multi-pulse having a plurality of second pulses corresponding to a second level in the input data, and a cooling pulse connecting the first multi-pulse and the second multi-pulse, wherein a power level of a leading pulse of the second multi-pulse is a high level or a low level of the second multi-pulse, and a power level between an end point of the second multi-pulse and a start point of the leading pulse of the first multi-pulse is a high level or a low level of the second multi-pulse; and

and a pickup unit that generates light to form a first state and a second state on the optical recording medium based on the first multi-pulse and the second multi-pulse in the recording waveform generated from the recording waveform generating unit.