KR100694023B1 - Method of compensating for defocus/tilt and apparatus therefor - Google Patents

Abstract

A defocus / tilt compensation method and apparatus are disclosed. The present invention provides a tilt compensator for detecting defocus / tilt of an optical recording medium and a recording compensator for compensating recording pulses having a predetermined recording pattern by a predetermined scheme according to the defocus / tilt detected by the defocus / tilt detector. Adjust the recording power according to the detected defocus, shift the recording pattern according to the detected tilt, and adjust the power level and / or recording time necessary for recording to mark the mark of the desired size (length and width). By recording, it is suitable for a high density optical disk system.

Description

Method of compensating for defocus / tilt and apparatus therefor}

1 is a diagram for explaining coma aberration according to wavelength and numerical aperture.

2 is a view showing a change in peak intensity according to defocus.

3 is a view illustrating a change in spot size according to defocus.

4 is a diagram illustrating a profile change of a beam when defocus and tilt occur at the same time.

5 is a diagram illustrating changes in beam spot size and peak intensity when defocus and tilt occur at the same time.

m와 0.5

m일 때 기록 파워의 보상 효과를 보인 도면이다.6 shows a defocus of 0.25

m and 0.5

It is a figure which shows the compensation effect of recording power at m.

7 shows compensation recording power according to defocus.

8 is a table showing shift amounts of recording pulses for each recording power and changes in the length and width of recording marks according to tilt / defocus.

m일 때의 기록 파워 보상 효과를 보인 도면이다.9 shows when the tilt is 0.5 ° and the tilt is 0.5 ° & defocus 0.25.

The figure shows the recording power compensation effect at m.

10 is a diagram showing a compensation effect according to recording power and recording time when the tilt is 0.5 °.

11 (a) and 11 (b) show a write pattern of a write pulse used for defocus / tilt compensation according to the present invention.

m일 때의 기록 보상 효과를 보인 도면이다.12 has defocus from 2.6GB DVD-RAM 1

The figure shows the recording compensation effect at m.

Fig. 13 shows the recording compensation effect when the tilt is 1.0 DEG in 2.6GB DVD-RAM.

FIG. 14 is a view showing jitter change according to the recording compensation effect when the tilt is 1.0 DEG in 2.6 GB DVD-RAM.

15 is a flowchart according to an embodiment of a defocus / tilt compensation method according to the present invention.

16 is a block diagram according to an embodiment of a defocus / tilt compensation device according to the present invention.

The present invention relates to a defocus / tilt compensation method and apparatus thereof, and more particularly to a method and apparatus for compensating defocus / tilt by controlling power and / or time required for recording in accordance with defocus / tilt of an optical recording medium. It is about.

When defocused and recorded on discs that require high density recording in optical recording media, or when both tilt and defocus occur, the effects of defocus and tilt appear much greater than those using conventional red lasers. There is a need for a method.

Instead of using a conventional red laser (wavelength 650 nm), when using a high numerical aperture (NA) objective lens with a short wavelength (400 nm) blue laser for higher density, the system is shown in Table 1 below. Will affect. In particular, the items affecting the recording are a decrease in the margin as the tilt of the disc increases and the depth of focus becomes shallow.

On the other hand, in the present Digital Versatile Disc Random Access Memory (DVD-RAM), the allowable ranges of radial tilt and track tilt are 0.7 ° and 0.3 °, respectively. Basic disc characteristics must be satisfied within such an allowable range of tilt. For example, the power required for recording (recording power, erasing power, etc.) should be maintained at a power level sufficient to obtain recording characteristics defined by the disc standard.

However, as a high density recording is required, the effect of the tilt is large when a short wavelength blue laser (wavelength 400 nm) is used. This is much larger. The equation for this coma aberration is given by

Where n represents the refractive index of the substrate, d represents the thickness of the substrate, and NA represents the numerical aperture.

FIG. 1 illustrates three-dimensional coma aberration according to wavelength and numerical aperture when the substrate thickness is 0.6 mm, the substrate refractive index is 1.5, and the tilt is 0.5 ° using Equation 1 above. That is, the shorter the wavelength, the larger the numerical aperture, the coma aberration increases.

Further, since the intensity of the beam to record with tilt decreases very rapidly at a wavelength of 400 nm, and the spot size of the beam also increases, when recording in such a state, marks having a desired length and width cannot be recorded. Therefore, the power density is finally reduced because the beam size becomes larger as well as the reduction of the peak intensity. As a result, the temperature required to form the amorphous mark during recording is drastically reduced.

On the other hand, as a method for compensating the tilt, the margin of the tilt may be increased by making the substrate thickness of the disk thinner than the currently used 0.6 mm from the relation shown in Table 1 in terms of manufacturing of the disk. However, if the thickness of the substrate of the disk is thinner than 0.6 mm, there is a problem in terms of manufacturability and characteristics, and thus it cannot simply be made thinner than 0.6 mm. In addition, on the recording side, as the focus depth of the incident beam becomes shallower, the defocus margin becomes smaller, and therefore, even if a small amount of defocus is generated, it becomes a problem on the recording side. This will be described with reference to FIGS. 2 and 3 in which a change in beam intensity and spot size according to defocus at red and blue wavelengths is shown.

FIG. 2 is a diagram illustrating a change in intensity of a beam according to defocus, in which the horizontal axis represents defocus and the vertical axis represents the peak intensity of the normalized beam. As the defocus increases, the incident beam intensity decreases more rapidly when the wavelength is 400 nm and the numerical aperture NA is 0.65 than when the wavelength is 650 nm and the numerical aperture is 0.6. And marks with width cannot be recorded. Also, even with the same wavelength, the beam intensity decreases as the numerical aperture NA increases.

3 is a view showing a change in spot size of a beam according to defocus, in which the horizontal axis represents defocus and the vertical axis represents spot size ratio. As the defocus increases, the spot size increases when the wavelength is 400 nm than when the wavelength is 650 nm. Even though the wavelength has the same wavelength, the spot size increases as the numerical aperture NA increases.

Therefore, even if defocus occurs, normal recording cannot be performed because there is an influence on the peak power and the spot size in the same way as the effect by the tilt. In addition, it becomes even more problematic when defocus and tilt occur together. Beam shape, peak power, and spot size when defocus and tilt occur simultaneously are shown in FIGS. 4 and 5.

m인 경우의 빔 모양이고, 3은 디포커스가 0.5

m인 경우의 빔 모양이고, 4는 틸트가 0.5。인 경우의 빔 모양이고, 5는 틸트가 0.5。이고 디포커스가 0.25

m인 경우의 빔 모양이고, 6은 틸트가 0.5。이고 디포커스가 0.5

m인 경우의 빔 모양이다.4 shows a change in the beam profile when tilt and defocus occur simultaneously. 1 is the beam shape in steady state, 2 is 0.25 defocus

beam shape for m, 3 is 0.5 for defocus

m is the beam shape, 4 is the beam shape when the tilt is 0.5 °, 5 is the tilt is 0.5 ° and the defocus is 0.25

beam shape when m, 6 is 0.5 ° tilt and defocus is 0.5

Beam shape in the case of m.

m인 경우(2), 디포커스가 0.5

m인 경우(3), 틸트가 0.5。인 경우(4), 틸트가 0.5。이고 디포커스가 0.25

m인 경우(5), 틸트가 0.5。이고 디포커스가 0.5

m인 경우(6)를 각각 나타내고 있다. 세로축은 정상 상태의 피크 세기 대 틸트와 디포커스가 있는 경우의 피크 세기를 정규화한 값과 정상 상태의 스폿 크기와 틸트와 디포커스가 있는 경우의 스폿 크기를 정규화한 값을 나타내고 있다. 디포커스 또는 틸트가 커질 수록 피크 파워의 세기가 작아지고 스폿 크기는 커지며, 디포커스 또는 틸트가 단독으로 발생한 경우보다 디포커스와 틸트가 동시에 발생한 경우가 피크 파워의 세기가 더 작아지고 스폿 크기는 보다 더 커지는 것을 알 수 있다.FIG. 5 is a diagram showing changes in beam spot size and peak power intensity when tilt and defocus occur at the same time. The horizontal axis shows steady state (1) and the defocus is 0.25.

for m (2), defocus is 0.5

If m (3), if the tilt is 0.5 ° (4), the tilt is 0.5 ° and the defocus is 0.25

for m (5), the tilt is 0.5 ° and the defocus is 0.5

In the case of m (6) is shown, respectively. The vertical axis represents the normalized peak intensity versus the normalized peak intensity when there is tilt and defocus, and the normalized spot size and the spot size when there is tilt and defocus. The larger the defocus or tilt, the smaller the peak power intensity and the larger the spot size, and the smaller the peak power intensity and the smaller the spot size when the defocus and tilt occur simultaneously than when the defocus or tilt occurs alone. You can see that it gets bigger.

From the results shown in FIGS. 4 and 5, not only when defocus or tilt occurs but also when the defocus and tilt occur at the same time, a more serious effect occurs during recording, so that defocus / tilt compensation is necessary. It became.

Accordingly, it is an object of the present invention to provide a defocus / tilt compensation method for performing recording by adjusting the power and / or time required for recording in accordance with the defocus / tilt of the optical recording medium.

Another object of the present invention is to provide a method of compensating for a detected defocus first and then compensating for a detected tilt.

It is still another object of the present invention to provide a method for compensating for a recording pattern of a recording pulse adaptively according to the defocus / tilt of the detected optical recording medium.

It is still another object of the present invention to provide a defocus / tilt compensation device which performs recording by adjusting the power and / or time required for recording in accordance with the defocus / tilt of the optical recording medium.

Another object of the present invention is to provide an apparatus for compensating for the detected defocus first and then compensating for the detected tilt.

It is still another object of the present invention to provide an apparatus for adaptively compensating for a recording pattern of a recording pulse in accordance with the defocus / tilt of the detected optical recording medium.

In order to achieve the above objects, the defocus / tilt compensation method according to the present invention is a method for compensating defocus / tilt of an optical recording medium capable of recording / rewriting: detecting a defocus of an optical recording medium; and And performing compensation recording according to a predetermined system according to the detected defocus.

The present invention is further characterized by detecting a tilt of the optical recording medium and compensating for a recording pulse having a predetermined recording pattern in accordance with the detected tilt.                         

Further, the defocus / tilt compensation method according to the present invention is a method for compensating defocus / tilt of an optical recording medium recorded with marks and spaces by a recording pulse having a predetermined recording pattern for input data: Detecting defocus / tilt of the recording medium and compensation recording power according to defocus, shift amount of recording pattern according to tilt / mark length, power and / or time required for recording to compensate for the length and width of the mark And compensating for the recording pattern adaptively according to the defocus / tilt detected by using the stored memory.

A defocus / tilt compensation device according to the present invention is an apparatus for recording and / or reproducing information on an optical recording medium capable of recording / rewriting, comprising: a defocus / tilt detector for detecting defocus / tilt of an optical recording medium; And a write compensator for compensating write pulses having a predetermined write pattern by a predetermined scheme according to the defocus / tilt detected by the defocus / tilt detector.

Further, the defocus / tilt compensation device according to the present invention is a device for compensating defocus / tilt of an optical recording medium recorded in a mark and a space by a recording pulse having a predetermined recording pattern for input data. Defocus / tilt detector for detecting defocus / tilt of recording medium and compensation recording power according to defocus, shift amount of recording pattern according to tilt / mark length, power required for recording to compensate for the length and width of mark And / or a write compensator for adaptively compensating a recording pattern according to the defocus / tilt detected by the defocus / tilt detector using a memory in which time and the like are stored.

Hereinafter, with reference to the accompanying drawings will be described a preferred embodiment of the defocus / tilt compensation method and apparatus according to the present invention.

First, as described above with reference to FIG. 2, when defocus / tilt occurs, the peak intensity of the incident beam decreases very rapidly at a wavelength of 400 nm, and thus compensation for recording power is required. In addition, as described above with reference to FIG. 3, the increase in the spot size of the beam is insensitive to defocus / tilt at a wavelength of 650 nm, but is rapidly increased at a wavelength of 400 nm. This result can be seen in FIG. 5 that the deterioration is further exacerbated when the defocus and the tilt are present together. Therefore, when defocus occurs, not only the peak intensity of the beam is reduced, but also the effect of decreasing the power density by increasing the spot size of the beam is generated in the same way as when only the tilt is generated.

m에서 0.5

m로 증가함에 따라 기록된 마크의 길이 및 폭이 점차 감소하고 있다. 디포커스에 따라 감소된 마크의 길이 및 폭을 기록 파워로 보상할 경우, 디포커스 0.25

m에서는 기록 파워가 6.75mW일 때, 디포커스 0.5

m에서는 기록 파워가 8mW일 때 정상 상태와 동일한 마크의 모양을 얻을 수 있다. 따라서, 도 7에 도시된 바와 같이 디포커스에 따른 보상 기록 파워를 이용하여 원하는 기록 마크, 즉 디포커스가 없는 기록 마크와 동일하게 기록할 수 있음을 알 수 있다.The defocus effect of the incident beam can be seen in FIG. 6, which shows the shape of the mark according to the recording power at wavelengths of 650 nm and 400 nm, in particular the length and width of the mark. 0.25 as the defocus increases than in the case of the normal recording power of 6 mW

0.5 to m

As it increases to m, the length and width of the recorded mark gradually decrease. Defocus 0.25, when compensating for the recording power and the length and width of the marks reduced with defocus

m, defocus 0.5 when the recording power is 6.75 mW

In m, when the recording power is 8 mW, the same mark as in the normal state can be obtained. Therefore, as shown in Fig. 7, it can be seen that the desired recording mark, i.e., the recording mark without defocus, can be recorded using the compensation recording power according to the defocus.

m가 동시에 발생할 때, 각각 기록 파워를 정상 기록 파워인 6mW에서부터 1mW씩 증가시킨 경우에 대응하는 기록 위치의 시프트량, 기록 마크의 길이와 폭을 측정한 결과가 테이블로 도시되어 있다. 틸트가 0。일 때는 최적 기록 파워가 6mW이기 때문에 6mW보다 큰 기록 파워는 무의미하며, 틸트가 0.5。일 때는 8mW보다 큰 기록 파워는 무의미하다.8 shows when the tilt is zero, when the tilt occurs at 0.5 ° and when the tilt is at 0.5 ° and the defocus is 0.25.

When m occurs at the same time, the results of measuring the shift amount of the recording position and the length and width of the recording mark corresponding to the case where the recording power is increased by 1 mW from the normal recording power of 6 mW, respectively, are shown in a table. Since the optimum recording power is 6 mW when the tilt is 0 DEG, the recording power larger than 6 mW is meaningless. The recording power larger than 8 mW is meaningless when the tilt is 0.5 DEG.

m 디포커스가 동시에 발생한 경우의 기록 파워에 따른 기록 마크의 길이와 폭의 변화를 보이고 있다. 틸트가 0.5。 발생한 경우의 정상 상태의 마크의 폭을 얻기 위해 필요한 기록 파워와 정상 상태의 마크의 길이를 얻기 위해 필요한 기록 파워와의 차(

1)와 틸트 0.5。와 디포커스가 0.25

m가 동시에 발생한 경우의 정상 상태의 마크의 폭을 얻기 위해 필요한 기록 파워와 정상 상태의 마크의 길이를 얻기 위해 필요한 기록 파워와의 차(

2)가 거의 동일함을 알 수 있다. 9 is based on the results shown in FIG. 8 with a tilt of 0.5 ° and a tilt of 0.5 ° and 0.25.

The change in the length and width of the recording mark according to the recording power when m defocus occurs simultaneously is shown. The difference between the recording power required to obtain the width of the steady state mark when the tilt is 0.5 ° and the recording power required to obtain the length of the steady state mark (

1) with tilt 0.5。 and defocus 0.25

The difference between the recording power required to obtain the width of the steady state mark when m occurs at the same time and the recording power required to obtain the length of the steady state mark (

It can be seen that 2) is almost the same.

FIG. 10 is a diagram for explaining the compensation effect of a recording pattern not only by recording power but also by recording time when only tilt occurs (when tilt is 0.5 °) based on the result shown in FIG. Is controlled by the recording power, and the width of the mark is effectively compensated by the recording time. In particular, when compensating the width of the mark, compensation is made with the end time T _EFP of the first pulse and / or the start time T _SLP of the last pulse of the recording pattern shown in Fig. 11B. When the tilt is compensated only by the recording power, the mark length may be adjusted by the recording power as described above, and the width of the mark may be compensated by adjusting the recording power of the multi-pulse between the first pulse and the last pulse.

On the other hand, as shown in (b) of FIG. 11 for input NRZI (Non Return to Zero Inversion) data as shown in (a) of FIG. do. Here, this NRZI data is divided into a mark and a space, and the laser diode is turned off in the space period. If the disc is a DVD (Digital Versatile Disc), multi-pulse without changing the first pulse, the last pulse, and the cooling pulse to mark the NRZI data having a length of 3T, 4T, ..., 14T (where T is 1 bit long). Record only the number of changes.

That is, the recording pattern of the recording pulse according to the DVD standard is composed of the first pulse, the multi pulse chain and the last pulse, and the rising edge of the first pulse of the basic recording pulse is a time delayed from the rising edge of the recording mark. The rising edge of the first pulse can be shifted back and forth in units of 1 ns (nono second), and the last pulse can also be shifted back and forth in units of 1 ns. The multi-pulse sequence is divided into several short pulses to accumulate heat at the rear end of the recording mark. This reduces the deformation of the recording mark.

In FIG. 11B, 1 is a start time T _SFP of an initial pulse, 2 is an end time T _EFP of an initial pulse, 3 is a start time T _SLP of a last pulse, and 4 is The end time of the last pulse (T _ELP ) and 5 is the cooling pulse period (T _LC ). In addition, Pw is write power (also called peak light output), Pr is read light power, and Pb is bias power (also called erase light output). to be.

Therefore, the start point of the recorded mark is shifted by the beam shift by the tilt when recorded as a mark and a space on the disc with respect to the input NRZI data using the recording pulse having the recording pattern shown in Fig. 11B. do. To compensate for this, a shift of the recording pattern in accordance with the tilt is required.

m가 발생한 경우 기록 파워를 증가시키면 마크의 길이와 폭이 보상되는 것을 알 수 있다.FIG. 12 shows the experimental results of the compensation of recording power according to defocus using 2.6GB DVD-RAM. The simulation tends to be the same as the simulation result of FIG. 6, with the horizontal axis representing the recording power and the vertical axis representing the relative mark length. Each width is shown. The steady state power of the 2.6GB DVD-RAM is 12mW (= write power) / 3.0mW (= bias power) / 5.5mW (= read power) and the defocus is 0.1

It can be seen that when m occurs, increasing the recording power compensates for the length and width of the mark.

FIG. 13 is a diagram showing a result of a change in the length and width of a recording mark according to recording power compensation when a tilt of 1 ° occurs using the same disk (2.6GB DVD-RAM) shown in FIG. The power represents the length and width of the relative mark, respectively. It can be seen that controlling the recording power when there is a tilt compensates for the length and width of the mark.

FIG. 14 illustrates the change of jitter according to each power when there is no tilt and when the tilt is 1 ° using the same disk (2.6GB DVD-RAM) shown in FIG. 13. The axis represents the amount of jitter. In the normal state without tilt, jitter hardly occurs even when the recording power increases, but in the case where tilt exists, the jitter amount decreases as the recording power increases.

In conclusion, when only defocus occurs, the recording power can be compensated only. When defocus and tilt occur together, the shift of the beam due to tilt is compensated by shifting the entire recording pattern. The compensation of the width of the mark is controlled by the recording time, in particular by the end time T _EFP of the first pulse of the recording pattern and / or the start time T _SLP of the last pulse. In addition, when the defocus and the tilt are compensated only by the recording power, the mark length may be adjusted by the recording power, and the mark width may be compensated by adjusting the recording power of the multi-pulse between the first pulse and the last pulse.

m)이하인지를 판단한다(S102 단계).15 is a flowchart according to an embodiment of the defocus / tilt compensation method according to the present invention, in which the defocus / tilt is detected (step S101), and the detected defocus is a predetermined margin (

m) It is determined whether or not (step S102).

m)보다 크면 검출된 디포커스에 따라 기록 파워를 조절하고(S103 단계), S102 단계에서 판단한 결과가 디포커스가 소정의 마진(

m)이하이면 S101 단계에서 검출된 틸트가 소정의 마진(

。)이하인지를 판단한다(S104 단계).Defocus detected the result determined in step S102 is a predetermined margin (

If it is greater than m), the recording power is adjusted according to the detected defocus (step S103), and the result determined in step S102 indicates that the defocus has a predetermined margin (

m) or less, the tilt detected in step S101 is a predetermined margin (

It is determined whether or not (step S104).

。)보다 크면, 검출된 틸트에 따라 기록 펄스의 기록 패턴을, 틸트에 의해 시프트된만큼 역방향으로 시프트한 후(S105 단계), 기록 마크의 길이와 폭을 보상해서 틸트가 제로에 근접하도록 조절한다(S106 단계). S106 단계에서 마크의 길이의 보상은 기록 파워로 조절하고, 마크의 폭의 보상은 기록 시간으로 조절하되, 특히 기록 패턴의 최초 펄스의 끝 시간(T_EFP) 및/또는 최후 펄스의 시작 시간(T_SLP)으로 보상한다. 또한, 기록 파워만으로 틸트를 보상하는 경우, 마크의 길이는 상기와 같이 기록 파워로 조절하고, 마크의 폭은 최초 펄스와 최후 펄스 사이에 있는 멀티 펄스의 기록 파워를 조절하여 보상할 수도 있다.As a result of the determination in step S104, the tilt is a predetermined margin (

Is larger than the recording pattern, the recording pattern of the recording pulse is shifted in the reverse direction by the tilt (step S105), and then the length and width of the recording mark are compensated to adjust the tilt to be close to zero. (Step S106). In step S106, the compensation of the length of the mark is adjusted by the recording power, and the compensation of the width of the mark is adjusted by the recording time, in particular the end time (T _EFP ) of the first pulse of the recording pattern and / or the start time (T) of the last pulse. _SLP ) to compensate. In addition, when the tilt is compensated only by the recording power, the mark length may be adjusted by the recording power as described above, and the width of the mark may be compensated by adjusting the recording power of the multi-pulse between the first pulse and the last pulse.

m)이하일 뿐만 아니라 S104 단계에서 틸트가 소정의 마진(

。)이하이면 레이저 다이오드에 제공되는 기록에 필요한 파워 및/또는 시간을 그대로 유지해서 기록을 수행하거나, S103 단계에서 검출된 디포커스에 따라 보상된 기록 파워 또는 S106 단계에서 검출된 틸트에 따라 보상된 기록에 필요한 파워 및/또는 시간을 갖는 기록 펄스를 레이저 다이오드에 인가하여 기록을 수행한다.In step S107, defocus is a predetermined margin (

m) is less than or equal to a predetermined margin in the tilt step S104 (

If it is less than or equal to, recording is performed with the power and / or time required for the recording provided to the laser diode as it is, or the recording power compensated according to the defocus detected in step S103 or the tilt detected in step S106. The recording is performed by applying a recording pulse having the power and / or time necessary for writing to the laser diode.

Here, the compensation recording power according to defocus in step S103 and the shift amount, recording power and / or recording time required in steps S105 and S106 are shift amounts of the recording pattern according to the recording pattern (mark length) of the tilt / input data. By using a memory in which write power and / or write time for compensating the length and width of the and marks are stored, the detected defocus / tilt can be adaptively compensated. In addition, the memory may store power, time, and shift amount required for recording in response to defocus and tilt occurring at the same time, or defocus or tilt occurring alone.

16 is a block diagram according to an embodiment of a defocus / tilt compensation device according to the present invention, reference numeral 102 is an optical disk, 104 is a pick-up unit, 106 is a reproduction signal detector, 108 is a defocus / tilt detector, 110 is a write compensator, and 112 is a laser diode (LD) driver.

In Fig. 16, the pickup section 104 for driving the optical disk 102 includes an objective lens 1, a half mirror 2, a collimator lens 3, and the like. Mechanisms such as optical detectors (PD), laser diodes (LD) for detecting the optical signal reflected from the disk 102, and an actuator for focusing and tracking, although not shown in the drawing, It is built.

As a preferred example, the laser diode wavelength of the pickup section 104 is about 430 nm (blue wavelength) or less, and when the thickness of the disk substrate is 0.3 mm or more, the numerical aperture of the objective lens is 0.6 or more. If the thickness is 0.3 mm or less, one whose numerical aperture of the objective lens is 0.7 or more is used.

The reproduction signal detector 106 detects the reproduction signal from the output signal of the photo detector PD. The defocus / tilt detector 108 detects the tilt of the defocus / disc using the reproduction signal provided from the reproduction signal detector 106 or the output signal of the photo detector PD. During tilt detection, only tilt in the track direction may be detected.

When the defocus / tilt detector 108 detects defocus, the write compensator 110 generates a recording pulse that compensates the recording power according to the detected defocus, and detects to shift the starting point of the recording mark when the tilt is detected. The recording pulse is generated ahead of time by the shift amount in accordance with the tilted tilt, wherein the compensation of the mark length is adjusted by the recording power, and the compensation of the width of the mark is adjusted by the recording time, wherein the width of the mark is determined by the recording pattern. Compensation is made with the end time of the first pulse (T _EFP ) and / or the start time of the last pulse (T _SLP ). In addition, when the tilt is compensated only by the recording power, the mark length may be adjusted by the recording power as described above, and the width of the mark may be compensated by adjusting the recording power of the multi-pulse between the first pulse and the last pulse.

In addition, the recording compensator 110 has a compensation recording power according to defocus, a shift amount of a recording pattern according to the mark length of the tilt / input data, a recording power for compensating the length and width of the mark, and / or a recording time, etc. The stored memory may be incorporated to adaptively compensate for the defocus / tilt detected by the defocus / tilt detector 108.

The laser diode (LD) driver 112 converts the current into the laser diode LD for a write control time according to the power level of the write pulse adjusted from the write compensator 110 and flows the laser diode LD to the optical disk through the pickup unit 104. Write to 102. That is, when the laser diode is continuously turned on or off and heat is applied to the optical disk, the recording data is recorded as a recording mark.

In the present invention, the power (recording power, erasing power, etc.) required for recording should be increased by a certain amount according to the detected defocus / tilt, and the recording time is also adjusted and recorded. As a result, temperatures similar to those in the absence of defocus / tilt can be reached and thus marks of the desired size (length, width) can be recorded.

As described above, the present invention has the effect of recording a mark of a desired size (length, width) by adjusting the power level required for recording and / or the time required for recording in accordance with the detected defocus / tilt to compensate for the recording. And is suitable for high density optical disc systems.

Claims (20)

A method for compensating defocus / tilt of an optical recording medium capable of recording / rewriting: (a) detecting a defocus of the optical recording medium; (b) performing a compensation recording based on the detected defocus; (c) detecting the tilt of the optical recording medium; And (d) compensating for a recording pulse having a predetermined recording pattern based on the detected tilt. The defocus / tilt compensation method of claim 1, wherein the step (b) adjusts the optical power level according to the detected defocus. delete The method of claim 1, wherein step (d) (d1) shifting the recording pattern in the reverse direction by the shifted tilt according to the detected tilt; And (d2) adjusting at least one of power and time required for recording in order to compensate for the size of the recording mark corresponding to the recording signal. 5. The optical recording medium of claim 4, wherein in the step (d2), the compensation of the length of the mark is adjusted to the power necessary for recording, and the compensation of the width of the mark is adjusted to the time required for recording. Focus / Tilt Compensation Method. 6. The optical recording medium according to claim 5, wherein the compensation of the length of the mark is adjusted by recording power and the compensation of the width of the mark is adjusted by the end time of the first pulse of the recording pattern / start time of the last pulse. Defocus / Tilt Compensation Method. The optical recording medium of claim 4, wherein in the step (d2), the compensation of the length of the mark is controlled by a recording power, and the compensation of the width of the mark is controlled by a recording power of a multi-pulse string of a recording pattern. Defocus / Tilt Compensation Method. A method for compensating defocus / tilt of an optical recording medium recorded with marks and spaces by recording pulses having a predetermined recording pattern for input data: (a) detecting the defocus / tilt of the optical recording medium; And (b) By using a memory in which at least one of the compensation recording power according to defocus, the shift amount of the recording pattern according to the tilt / mark length, and the power and time required for recording to compensate for the mark length and width is stored; Compensating the recording pattern adaptively according to the defocus / tilt detected in step a). An apparatus for recording and / or reproducing information on an optical recording medium capable of recording / rewriting: A defocus / tilt detector for detecting the defocus / tilt of the optical recording medium; And A write compensator for compensating write pulses having a predetermined write pattern based on the defocus / tilt detected by the defocus / tilt detector, And the write compensator adjusts at least one of power and time required to record the write pulse in accordance with the detected tilt. 10. The apparatus of claim 9, wherein the write compensator adjusts the optical power level required to record the write pulse in accordance with the detected defocus. delete The recording compensator of claim 9, wherein the recording compensator adjusts the recording power according to the detected defocus, and generates a recording pulse that is temporally advanced by shifting the recording pattern according to the detected tilt according to the detected tilt, A defocus / tilt compensation device, characterized in that for generating a compensated write pulse having a write pattern with at least one of power and time adjusted to compensate for length and width. 13. The defocus / tilt compensation apparatus according to claim 12, wherein the compensation of the length of the mark is adjusted by the power necessary for recording, and the compensation of the width of the mark is adjusted by the time required for recording. The defocus / characterization method according to claim 13, wherein the compensation of the length of the mark is adjusted by the recording power, and the compensation of the width of the mark is adjusted by the end time of the first pulse of the recording pattern / the start time of the last pulse. Tilt Compensation Device. 13. The defocus / tilt compensation apparatus according to claim 12, wherein the compensation of the length of the mark is adjusted by recording power, and the compensation of the width of the mark is adjusting power of the multi-pulse string of the recording pattern. 10. The apparatus of claim 9, wherein the write compensator further comprises a light source for providing a write pulse, the wavelength of the light source being less than or equal to the blue wavelength of 430 nm. 10. The defocus / tilt compensation device according to claim 9, wherein the substrate thickness of the optical recording medium is 0.3 mm or more, and the numerical aperture of the objective lens is 0.6 or more. 10. The defocus / tilt compensation device according to claim 9, wherein the substrate thickness of the optical recording medium is 0.3 mm or less, and the numerical aperture of the objective lens is 0.7 or more. An apparatus for compensating defocus / tilt of an optical recording medium recorded in marks and spaces by recording pulses having a predetermined recording pattern for input data: A defocus / tilt detector for detecting tilt of the optical recording medium; And The defocus / tilt is stored using a memory in which at least one of a compensation recording power according to defocus, a shift amount of a recording pattern according to the length of the tilt / mark, and a power and time required to compensate for the length and width of the mark are stored. A defocus / tilt compensation device comprising a write compensator for adaptively compensating a recording pattern according to the defocus / tilt detected at the detector. 20. The memory of claim 19, wherein the memory stores at least one of power, time, and shift amount required for recording, respectively, when the defocus and the tilt occur at the same time and the defocus or the tilt occur alone. Defocus / Tilt Compensation Device.

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