KR100628173B1 - Controlling method and apparatus for record/playing of optical record medium - Google Patents

Abstract

A method and apparatus for controlling recording and reproducing of an optical recording medium in which a plurality of non-recording areas having different phases are arranged between the recordable data areas to distinguish shapes of the data area. By performing the servo with the focus error signal and the tracking error signal averaged by the pass filtering, it is possible to eliminate the track slipping phenomenon and stabilize the tracking servo, thereby preventing deterioration of recording and reproducing characteristics.

Land, groove, heather

Description

Controlling method and apparatus for recording and reproducing an optical record carrier {Controlling method and apparatus for record / playing of optical record medium}

1 is a block diagram of a general optical recorder

2 is a diagram illustrating an example of the photo detector of FIG. 1;

FIG. 3 shows the arrangement of a header preformatted at the start of each sector in a typical rewritable disc. FIG.

4 is a waveform diagram illustrating a general example of sample / holding a tracking error value in a header section of FIG.

FIG. 5 is a waveform diagram illustrating an example of a track error occurring when a sample / hold of a header section existing when switching from a land to a groove

FIG. 6 is a waveform diagram illustrating an example of a track error occurring when a sample / hold of a header section existing when switching from a groove to a land track

7 is a block diagram of an optical recorder according to the present invention.

8A to 8E are waveform diagrams showing a servo control process of a header area in the optical recorder according to the present invention.

Explanation of symbols for main parts of the drawings

101: optical disk 102: optical pickup

103: high frequency (RF) and servo error generation unit 105: offset adjustment unit

106: header mask and L / G switching signal generator

107: servo control unit 108: servo drive unit

201,202: LPF 203: switching part

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rewritable optical recording medium system, and more particularly, to a method and apparatus for controlling recording and reproducing of an optical recording medium in which a plurality of non-recording areas having different phases are arranged to distinguish the shape of the data area between recordable data areas. It is about.

Generally, freely and repeatedly rewritable optical recording media such as an optical disc include a rewritable compact disc (CD-RW) and a rewritable digital versatile disc (DVD-RW, DVD-RAM, DVD). + RW).

At this time, the above-described rewritable optical disc, particularly DVD-RAM, has a signal track having a structure of land and groove, so that data can be recorded not only on the track of the land or groove, but also on the track of the land and groove. Can play.

FIG. 1 is a block diagram of the optical disk recording / reproducing apparatus. The optical pickup 102 causes the light beam focused on the objective lens to be placed on the signal track of the optical disk 101 by the control of the servo control unit 107. In addition, the light reflected from the signal recording surface is condensed by the objective lens and then incident on the photo detector for detecting the focus error signal and the tracking error signal. The photo detector includes a plurality of photo detectors, and an electrical signal proportional to the amount of light obtained by each photo detector is output to the high frequency RF and the servo error generator 103.

If the optical detector is composed of four optical detection elements (PDA, PDA, PDC, PDD) that are specifically divided in the signal track direction and the radial direction of the optical disc 101 as shown in FIG. The detector outputs the electrical signals a, b, c, and d in proportion to the amount of light obtained from each of the photodetecting devices PDA, PDB, PDC, and PDD to the high frequency RF and the servo error generator 103.

The high frequency (RF) and servo error generation unit 103 combines the electrical signals a, b, c, and d to provide a read channel 1 signal (or a high frequency (RF) signal) required for data reproduction and servo control. Generate the required lead channel 2 signal, focus error signal, etc.

Here, the read channel 1 signal R-ch1 may be obtained by (a + b + c + d) an electrical signal output from the photo detector, and the read channel 2 signal R-ch2 may be obtained by the photo detector. The electrical signal output from the signal can be obtained by (a + d)-(b + c), and the tracking error (TE) signal can be obtained by processing the read channel 2 signal R-ch2. If the photo detector is divided into two in the track direction, a high frequency (RF) signal (= I1 + I2) and a read channel 2 signal (= I1-I2) are detected from the light amount balance of both photodiodes I1 and I2. do. That is, a + d in FIG. 2 corresponds to I1 and b + c corresponds to I2.

At this time, in the case of the DVD-RAM 101 as described above, since there is no information on the first disc, disc control and recording are impossible.

To this end, disc tracks are created in lands and grooves, information is recorded along the tracks, and control information for sector address, random access, rotation control, etc. is separately recorded on the disc, whereby no information signal is recorded. Allows tracking control even on the disc. The control information may be recorded by pre-formatting the header area at each sector at the start of the sector.

At this time, the header area pre-formatted at the start position of each sector is composed of four header fields (header 1 field and header 4 field) again. Here, the header 1,2 fields and the header 3,4 fields are alternately arranged from the track center, and FIG. 3 is an example of the structure of the header field for the first sector in one track.

However, such a header structure adversely affects generating servo error signals such as tracking error signals and focus error signals. That is, the servo error signal read out from the header area is distorted according to the header structure, and it is difficult to control it.

Therefore, in the case of DVD-RAM, in order to generate a servo error signal and control it stably, the header area is less influenced by holding each servo error signal, for example, a tracking error signal and a focus error signal to control the servo. To lose.

That is, the focus sample & hold unit 104-1 of the sample & holder 104 samples and holds the focus error signal FE in the header area, and the tracking sample & hold unit 104-2 tracks in the header area. By holding the error signal TE, the light beam does not leave the track center. In the header area, the focus servo and the tracking servo are held, not the tracking error signal or the focus error signal detected in the header area.

In this case, there are various methods of detecting the header area, and the header mask signal and the L / G switching signal generator 106 detect the header area and indicate a header mask signal (HDM) during the detected header area. ) Is generated and output to the sample & holder 104.

Here, the header region may be detected by slicing the lead channel 1 signal, or may be detected by slicing the lead channel 2 signal, or may be detected as a combination of the two signals after generating the IP1 and IP2 signals from the lead channel 2 signal. have. That is, since the header 1,2 field and the header 3,4 field of the header area are alternately arranged with respect to the track center, when the lead channel 2 signal of the header area is sliced, the IP1 and IP2 signals can be detected. For example, assuming that the track center is set at the slice level, and the lead channel 2 signal is higher than the slice level, the IP1 signal is output and if the track channel is low, the IP2 signal is output. The phase of the signal and the IP2 signal are reversed. That is, the IP1 signal may come first or the IP2 signal may come first depending on the land / groove track.

On the other hand, the tracking error signals in the lands are inverted relative to each other when compared with the tracking error signals in the grooves. That is, since the tracking error signal detected in the land and the tracking error signal detected in the groove are reversed, the tracking error signal obtained from the land and the groove must be in phase in order to follow the track normally in both the land and the groove.

In addition, there is a difference in the DC offset (that is, a signal generated by the L / G depth difference) that the land and the groove basically have due to the difference between the land and the groove. In other words, even if the focus and tracking are correct on the track of the land, if you apply it to the track of the groove as it is, the groove may be defocused and detracked. In this case, defocus and detrack may occur due to the depth difference between land and groove.

Accordingly, an offset adjustment unit 105 is provided, and the focus offset adjustment unit 105-1 of the offset adjustment unit 105 adjusts the focus error offset for each groove / land so as to perform normal focus servo. In addition, the tracking offset adjusting unit 105-2 adjusts a tracking error offset for each groove / land so as to perform normal tracking servo and inverts the tracking error signal detected in the land.

In addition, according to the L / G switching signal L / Gsw output from the header mask signal and the L / G switching signal generation unit 106, that is, when the current signal track indicates a land, the focus is offset and adjusted to fit the land. An error signal and an inverted tracking error signal are selected, and when a groove is displayed, a focus error signal and a tracking error signal that are offset adjusted to the groove are selected and output to the servo controller 107. Accordingly, the servo controller 107 performs the focus servo and the tracking servo with a focus error signal and a tracking error signal that are offset and adjusted to lands through the focus / track (F / T) servo driver 108. Alternatively, the focus servo and the tracking servo may be performed with the focus error signal and the tracking error signal offset adjusted to the groove, which are determined by the L / G switching signal L / Gsw. Here, L / G means a case in which a signal track is changed from a land to a groove or from a groove to a land.

That is, since the IP1 signal may come first or the IP2 signal may come first depending on whether the current track is a land or a groove, the header mask and the L / G switching signal generator 106 may look forward or backward of the IP1 and IP2 signals. It is determined whether the track is a land or a groove, and the L / G switching signal L / Gsw is inverted and output to the offset adjustment unit 105 at every L / G change.

At this time, one of the methods of holding the focus and tracking error signals during the header section is a method of sampling and holding the focus and tracking error values immediately before the header section starts. In addition, a header mask is put on the header section existing during the L / G switching so as not to deviate from the track center, and the value immediately before the header section is sampled and held during the header section.

However, in the header section existing during L / G switching, the tracking error signal of the previous track (before inverting) is sampled and held and then inverted to perform tracking servo, thereby causing a problem of increasing track error.

For example, in the header section existing when switching from land to groove, the tracking error signal detected in the land is sampled and then switched to the groove, and the held value is inverted to perform tracking servo. At this time, since the DC offset is different between the land and the groove by the depth difference between the land and the groove, as shown in FIG. In other words, the land offset becomes larger by inverting.

In addition, in the header section existing when switching from the groove to the land, the tracking error signal detected in the groove is sampled and then switched to the land, and the held value is inverted to perform the tracking servo. Similarly, in the header section existing when switching from groove to land, as shown in FIG. 6, a track error increases when switching from groove to land. This problem also occurs when the error is large in the header area existing in the land track or groove track, not the L / G switching section.

FIG. 5 is a waveform diagram illustrating an example of a track error that occurs when a sample / hold of a header section existing when switching from a land to a groove, and FIG. 6 illustrates a sample of a header section that exists when switching from a groove to land, FIG. This is a waveform diagram showing an example of a track error.

As described above, when the servo becomes unstable or the header area is present during the land / groove track switching, the following problem may occur as the value of the previous track section is sampled and held and inverted.

First, when the land / groove track is switched, header detection may not be performed properly, and track slippage may occur.

Second, track servo becomes unstable due to discrete track error variations. In particular, the slad servo may become unstable.                         

Third, instability of the track servo degrades recording and playback characteristics, resulting in poor eye patterns and jitter.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to provide a method and apparatus for controlling recording and reproducing of an optical recording medium which performs servo with a servo error signal averaged to such an extent that the influence of the header area is eliminated in the header area. In providing.

According to an aspect of the present invention, there is provided a method of controlling recording and reproducing of an optical recording medium, the method comprising: detecting a non-recording area, that is, a header area, and a servo generated by using a light reflection signal from the optical recording medium. Averaging the error signal, selectively outputting the servo error signal averaged in the step in the header area detected in the step, and selectively outputting the servo error signal before being averaged in the non-header area; And performing a servo with a servo error signal that is selectively output from the controller.

In the averaging step, the servo error signal may be averaged by low pass filtering.

An apparatus for recording and reproducing an optical recording medium according to the present invention includes a header area detection unit for detecting a header area that is a non-record area and outputting a header mask signal indicating a header area, and a light reflection signal from the optical recording medium. An averaging unit for averaging one servo error signal, and outputting a servo error signal averaged by the averaging unit when a header mask signal is output from the non-recording area detection unit, and bypassing the averaging unit if a header mask signal is not output. And a servo unit configured to selectively output a servo error signal, and a servo unit configured to perform servo with the servo error signal selected and output from the selector.

The averaging unit is configured as a low pass filter.

Other objects, features and advantages of the present invention will become apparent from the following detailed description of embodiments taken in conjunction with the accompanying drawings.

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

The present invention is to perform the servo with a servo error signal averaged to the extent that the influence of the header is removed in the header section.

FIG. 7 is a block diagram of an optical recorder according to the present invention, and includes a first LPF 201 and a tracking error signal for performing low pass filtering on a focus error signal detected by a radio frequency (RF) and servo error generator 103. Referring to FIG. Low pass filtering in the first and second LPFs 201 and 202 according to the second LPF 202 performing low pass filtering, the header mask and the header mask signal HDM output from the L / G switching signal generator 106. 1, in which the selected focus, tracking error signal, or the selector 203 for selecting the focus and tracking error signal bypassing the first and second LPFs 201 and 202 and outputting the selected focus and tracking error signal to the offset adjustment unit 105 is further described. It is provided.

In the present invention, the same reference numerals are used for blocks having the same configuration and operation as those in FIG. 1, and detailed descriptions thereof are omitted.

That is, in the header section, each servo error signal, for example, a tracking error (TE) signal and a focus error (FE) signal, is held, but not held at the previous sample level as in the conventional method. By holding the low pass filtered signal level to such an extent that the effect is eliminated, the influence of the header is reduced.

To this end, the header mask and the L / G switching signal generator 106 may use the read channel 1, read channel 2, IP1, and IP2 signals provided by the high frequency (RF) and servo error generator 103 as shown in FIG. A header mask signal (HDM) indicating a header area is generated, and L / G switching signals (L / Gsw) are generated by determining whether the IP1 and IP2 signals are later.

Meanwhile, the first LPF 201 removes and averages high frequency components of the focus error signal output from the high frequency RF and the servo error generator 103, and the second LPF 202 performs the high frequency RF and The high frequency component of the tracking error signal output from the servo error generator 103 is removed and averaged. At this time, the filter bands of the LPFs 201 and 202 are set so that the influence of the header is almost eliminated.

In this case, the selector 203 outputs a header mask signal HDM indicating the header area from the header mask and the L / G switching signal generator 106, that is, the first and second LPFs 201 and 202 in the header area. ) Selects a low pass filtered focus error signal and a tracking error signal and outputs them to the offset adjustment unit 105. In other cases, that is, in the recording area, the focus error signal and the tracking error signal that do not pass through the first and second LPFs 201 and 202 are selected and output to the offset adjustment unit 105.

8 is a diagram illustrating a holding process of a tracking error signal, in which a header region is represented by a header mask signal as shown in (e), and (d) is an example of an L / G switching signal when the header region is present in an L / G change section. Is showing. At this time, since the header area is a non-recording area, a tracking error signal is largely generated in the header area as shown in (a). Therefore, when the low pass filtering of the tracking error signal of the header area of (a) in the second LPF (202) is averaged as shown in (b). In other words, the tracking error signal is output almost close to the straight line even in the header section. Therefore, even if the focus error signal and the tracking error signal are not held to the previous values in the header section, the servo is hardly influenced by the header.

In particular, even in the case of L / G switching, even if the tracking error signal bounces due to L / G switching occurring in the middle of the header area, the amount of bouncing is negligibly small. Also, even if L / G switching occurs in the early part of the header area, the tracking error signal stops and the LPF can follow the track desired by the servo. If the tracking error signal bounces when L / G switching occurs at the end of the header area, the light beam does not leave the track center because the track is followed by the LPF.

Since the subsequent operation, that is, the operation after the offset adjustment unit 105 is the same as in FIG. 1 described above, detailed description thereof will be omitted.

As described above, according to the method and apparatus for controlling recording and reproducing of an optical recording medium according to the present invention, in the header section of an optical disc having a land / groove structure, the servo is operated with a focus error signal and a tracking error signal averaged by low pass filtering. By doing so, the track slipping phenomenon can be eliminated and the tracking servo can be stabilized, thereby preventing deterioration of recording and reproducing characteristics.

Those skilled in the art will appreciate that various changes and modifications can be made without departing from the spirit of the present invention.

Therefore, the technical scope of the present invention should not be limited to the contents described in the embodiments, but should be defined by the claims.

Claims (7)

In the recording and reproducing control method of an optical recording medium in which a plurality of non-recording areas having different phases are disposed between the recordable data areas to distinguish the shape of the data area. Detecting the non-recorded area; Averaging a focus error signal and a tracking error signal generated using the light reflection signal from the optical recording medium; Selecting and outputting the focus error signal and tracking error signal averaged in the step in the non-recorded area detected in the step, and outputting the non-averaged focus error signal and tracking error signal in the non-recorded area; And And performing a servo based on the focus error signal and the tracking error signal selectively output in the step. The method of claim 1 wherein the averaging step is And a low pass filtering of the focus error signal and the tracking error signal to average them. The method of claim 1, And the non-recorded area is a header area. Recording and reproducing of an optical recording medium having land and groove track structures having different depths in the direction of light incidence, and having a plurality of non-recording regions of different phases arranged for distinguishing the shape of the data region between recordable data regions. In the apparatus, A non-recording area detector for detecting the non-recording area and outputting a non-recording area detection signal; An averaging unit for averaging a focus error signal and a tracking error signal generated by using the light reflection signal from the optical recording medium; When the non-recording area detection signal is output from the non-recording area detection unit, a focus error signal and a tracking error signal averaged by the averaging unit are selectively outputted, and if the non-recording area detection signal is not output, the focus error signal bypasses the averaging unit. And a selector for selectively outputting a tracking error signal. And And a servo unit for performing servo based on a focus error signal and a tracking error signal selected and output from the selection unit. The method of claim 4, wherein And the averaging part comprises a low pass filter. The method of claim 4, wherein The averaging unit includes a first low pass filter for low pass filtering the focus error signal and a second low pass filter for low pass filtering the tracking error signal. The method of claim 4, wherein the servo unit A change signal output unit for outputting a land / groove change signal when the land / groove change is confirmed; A land offset adjuster for offset-adjusting a focus error signal and a tracking error signal output through the selector to a land; A groove offset adjustment unit for offset-adjusting a focus error signal and a tracking error signal output through the selector to a groove; An error signal output unit for selectively outputting a focus error signal and a tracking error signal offset and adjusted to a land or a groove according to the land / groove change signal; And a servo control unit which performs a servo based on the selected output focus error signal and tracking error signal.

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