KR100587266B1 - Recording / Reproducing Method of Optical Recording Medium - Google Patents

Abstract

The present invention relates to a header section sample / hold method for a rewritable optical record carrier having land and groove structures. In particular, in the present invention, when the land / groove track is switched, a tracking servo is performed by holding or fixing a DC offset voltage in a header section existing when the land / groove track is switched, or by holding an average value of the same track before. Accurate header detection is achieved to eliminate track slippage and to stabilize the tracking servo, thereby preventing deterioration of recording and playback characteristics.

Land, groove, heather

Description

Method for recording and reproducing an optical recording medium {Method for recording / playing of optical recording medium}

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

FIG. 2 is a waveform diagram illustrating a general example of sampling / holding a tracking error value in a header section of FIG. 1. FIG.

FIG. 3 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

4 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

5 is a block diagram of an optical disk recording / reproducing apparatus according to the present invention;

6 is a waveform diagram illustrating an example of the present invention for sample / holding a tracking error value in a header section during land / groove track switching.

Explanation of symbols for main parts of the drawings

101: optical disk 102: optical pickup

103: high frequency (RF) and servo error generation unit 104: sample / hold unit

105: groove offset portion 106: land offset portion

107: land / groove switching unit 108: land / groove determination unit

109: sample value determination unit 110: servo control unit

111: servo driver

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rewritable optical record carrier system, and more particularly to a method for recording and reproducing an optical record carrier for sample / holding a header section of an optical record carrier having a land and groove structure.

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).

In this case, the above-described rewritable optical disc, particularly DVD-RAM, has a signal track having a structure of land and groove, so that tracking control can be performed even on a blank disc in which no information signal is recorded. Recently, in order to increase the recording density, information signals are recorded in tracks of lands and grooves, respectively. To this end, the wavelength of the laser light of the optical pickup for recording / reproducing is shortened, and the numerical aperture of the objective lens for condensing is increased to reduce the size of the light beam for recording and reproducing.

Further, in such a high density optical disc, the distance between signal tracks, i.e., the signal track pitch, is reduced in order to increase the recording density.

In this case, in the case of a rewritable disc, since the first disc has no information, disc control and recording are impossible. For this purpose, disc tracks are created in lands and grooves, and information is recorded along the tracks. Information for random access and rotation control is recorded separately on the disc, so that tracking control can be performed on a blank disc in which no information signal is recorded. To do it.

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 preformatted at the start position of each sector is further composed of four header fields (header 1 field and header 4 field). Here, the header 1,2 field and the header 3,4 field are staggered from each other from the track center, and FIG. 1 is an example of the structure of the header field for the first sector in one track. That is, the phases of the header 1,2 fields are inversely opposite to the header 3,4 fields, and the phases of the tracking error signals detected in the header 1,2 fields and the header 3,4 fields are opposite to each other.

Accordingly, in the track servo section, the header mask is covered and the track error signal is held as shown in FIG. 2 so as not to be out of the track center. In other words, the tracking servo is performed in the header section but is a held value, not a tracking error signal detected in the header section.

At this time, one of the methods of holding the tracking error signal during the header section is a method of sampling and holding the tracking error value just before the start of the header section.

On the other hand, in a land / groove recording / reproducing disc such as a DVD-RAM, the tracking error signals in the land are inverted relative to each other in the groove, so a separate circuit for this is required.

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 (DC) offset (that is, the 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.

Therefore, the separate circuit described above serves to match the tracking error offset in each land / groove as well as inverting the tracking error signal detected in the land in order to perform normal servo.

At this time, a header mask is put on the header section existing in the land / groove track 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 when switching the land / groove track, the tracking error signal of the previous track (before inverting) is sampled and held and then inverted so that the tracking servo is performed, thereby increasing the 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 due to the depth difference between the land and the groove, as shown in FIG. 3, the tracking error signal bounces as much as the offset amount of the land when the switch is switched from the land to the groove. 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. 4, a track error increases when switching from groove to land.

FIG. 3 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, and FIG. 4 is a waveform diagram illustrating an example of a track error occurring 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 header region is present during the land / groove track switching, the following problem may occur as the value of the previous track section is sampled / 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 sled 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 An object of the present invention is to solve the above problems, and an object of the present invention is to record and reproduce an optical recording medium which performs a tracking servo by holding a fixed DC offset voltage in a header section during land / groove track switching. In providing.

Another object of the present invention is to provide a recording / reproducing method of an optical recording medium which performs tracking servo by holding a tracking error value of a previous track in a header section during land / groove track switching.

According to an aspect of the present invention, there is provided a method of recording and reproducing an optical recording medium, comprising: a plurality of first and second tracks having different depths in the direction of light incidence, Checking whether the first track to the second track or the second track to the first track of the optically repeated recording medium is alternately present; And holding a servo control signal of the same previous track, and performing a tracking servo with the held servo control signal in the header section within the track change section.
The holding step is characterized by holding the average value of the servo control signal detected in a predetermined section of the same track before.
In the holding step, the servo control signal immediately before the header section is sampled and held in the header section existing in the first track or the second track except the track change section.
According to the present invention, there is provided a method of recording and reproducing an optical recording medium, comprising: a plurality of first and second tracks having different depths in the direction of light incidence, wherein the first track and the second track are alternately present Checking whether the first track to the second track or the second track to the first track of the recording medium is changed; and if the track change section is confirmed in this step, holding a preset DC offset voltage. And performing a tracking servo with a held DC offset voltage in the header section within the track change section.
The DC offset voltage held in the track change section may vary depending on whether the change track is a first track or a second track.
The DC offset voltage held in the track change section is the same regardless of the change track.
According to the present invention, there is provided a method of recording and reproducing an optical recording medium, comprising: a plurality of first and second tracks having different depths in the direction of light incidence, wherein the first track and the second track are alternately present Checking whether the first track to the second track or the second track to the first track of the recording medium is changed; and in the header section existing within the track change section, tracking servo is performed by holding the first sample value. And performing a tracking servo by holding a second sample value different from the first sample value in a header section existing within the section except for the track change section.
The servo step in the track change section is characterized by holding the servo control signal of the same track as the first track as the first sample value.
The servo step in the track change section is characterized by holding the average value of the servo control signal detected in a predetermined section of the same track as the first sample value.
The servo step in the track change section is characterized by holding the preset DC offset voltage as the first sample value.
In the servo step other than the track change section, the servo control signal immediately before the header section is held as a second sample value.
In the optical recording medium recording and reproducing method according to the present invention, a land track to a groove track or a groove track to a land track of an optical recording medium in which lands and groove tracks having different depths alternately exist in the direction of light incidence. Selecting and holding one of a servo control signal and a preset DC offset voltage of a previous track identical to the track to be changed if the track change interval is determined in the step; The header section in the change section is characterized in that it comprises the step of performing the tracking servo to the value held in the step.
The holding step is characterized in that to select and hold the DC (DC) offset voltage of the preset groove track when it is confirmed that the change from the land track to the groove track.
The holding step is characterized in that to select and hold the DC (DC) offset voltage of the predetermined land track when it is confirmed that the change from the groove track to the land track.
The holding step is characterized in that the DC offset voltage selected and held in the track change section is the same regardless of the change track.
The holding step is characterized in that if the change from the land track to the groove track is changed to select and hold the average value of the servo control signal detected in a predetermined section of the previous groove track.
The holding step is characterized in that if the change from the groove track to the land track is changed to select and hold the average value of the servo control signal detected in a predetermined section of the previous land track.
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.

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

The present invention is to perform tracking servo by holding a fixed DC offset value in a header section existing during land / groove track switching or by sample / holding an average value of a tracking error signal of the same track before.

FIG. 5 is a block diagram of a recording / reproducing apparatus for performing a header section sample / hold of an optical recording medium according to the present invention. The optical disk 101 has a structure of lands and grooves to enable rewriting of data. Optical pickup 102 for recording and reproducing information on 101, and radio frequency (RF) and servo error generation unit (103) for generating high frequency (RF) and servo error signals from electrical signals output from the optical pickup (102). ), A sample / hold unit 104 holding a predetermined sample value in a header section, and a groove offset unit 105 adjusting a direct current (DC) offset of a tracking error signal input through the sample / hold unit 104. After inverting the tracking error signal input through the sample / hold unit 104, the land offset unit 106 adjusts a direct current (DC) offset, and the groove offset unit 105 may be formed by a land / groove discrimination signal. Select output or output of land offset section 106 The land / groove switching unit 107 outputs a header mask signal to the sample / hold unit 104 when a header section is detected. The land / groove switching unit determines a land / groove from a signal of a header region. A sample value determination unit 109 for determining a sample value to be held by the sample / hold unit 104 according to the land / groove determination unit 108 and the determination signal of the land / groove determination unit 108 output to 107. ), A servo controller 110 for converting a signal output through the land / groove switching unit 107 into a tracking drive signal, and a tracking drive signal output from the servo controller 110 in the optical pickup 102. It is composed of a servo driver 111 for driving a tracking actuator to perform a tracking servo.

In the present invention configured as described above, the optical disc 101 has a signal track structure of lands and grooves, and data can be recorded or reproduced not only on the tracks of the lands or grooves, but also on the tracks of the lands and grooves.

At this time, 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 under the control of the servo driver 111, and also condenses the light reflected by the signal recording surface back to the objective lens. It then enters the photo detector for detection of the focus error signal and 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.

The radio frequency (RF) and servo error generator 103 may include a radio frequency (RF) signal for data reproduction, a focus error signal (FE) for servo control, and a tracking error signal (TE) from an electrical signal output from the photo detector. And the like.

In this case, the tracking error signal TE is input to the sample / hold unit 104.

The sample / hold unit 104 holds the sample value determined by the sample value determiner 109 during the header period so that the light beam does not leave the track center. Here, whether the sample / hold unit 104 has a sample / hold operation is determined by a header mask signal output from the land / groove discriminator 108.

That is, the sample / hold unit 104 samples and holds the tracking error value immediately before the header section in the header section within the land or groove under the control of the sample value determiner 109.

However, in the header section existing during land / groove track switching, the value sampled by the control of the sample value determiner 109 is fixed to a reference level, that is, a direct current (DC) offset voltage (for example, 2V), thereby FIG. 6. As described above, an increase in a track error after passing a header section can be reduced.

In this case, the DC offset voltage may be the same when switching from a land to a groove and when switching from a groove to a land, but may be applied differently.

In other words, since the DC / DC offset of the land / groove varies according to the land / groove depth difference, the DC / DC offset voltage of the groove when switching from land to groove, and the DC of the land when switching from groove to land. Hold with (DC) offset voltage.

Meanwhile, the sample / hold unit 104 may hold the average value of the tracking error of the same track section before fixing and holding the DC offset voltage during land / groove track switching.

In this case, a value obtained by averaging the tracking error values of the same track section before a certain section may be stored and held in the header section when the land / groove track is switched. Here, instead of the average value, the tracking error value of the previous track section may be stored and held.

For example, assuming that a header section exists, the current land is switched to a groove. At this time, the average value of the tracking error value of the previously stored groove is sampled and held. In this case, since the value of the same track section is held, the track error can be eliminated when switching the land / groove track.

In addition, assuming that the current groove is switched to the land, at this time, the average value of the tracking error value of the previously stored land is sampled and held.

On the other hand, the value held in the above-described process is input to the groove offset unit 105 and the land offset unit 106. In this case, the groove offset unit 105 adjusts the DC offset of the held value or the value of the tracking error to match the groove, and the land offset unit 106 adjusts the value of the held value or the tracking error. Adjust the DC offset of DC to fit the land and invert it.

In addition, the land / groove switching unit 107 may be a DC (DC) offset adjusted value in the groove offset unit 105 or a DC in the land offset unit 106 according to the determination signal of the land / groove determination unit 108. DC) After being offset, the inverted value is selected and output to the servo controller 110.

The land / groove determination unit 108 outputs a header mask signal to the sample / hold unit 104 when a header region is detected, determines a land and a groove from the signal of the header region, and then determines the land / groove switching unit ( 107) and a sample value determination unit 109 output a discrimination signal.

That is, the sample value determiner 109 may determine any one of the above-described values as a sample value in the header section existing during land / groove switching according to the determination result of the land / groove discriminator 108.

The servo controller 110 converts a value output through the land / groove switching unit 107 into a tracking drive signal, and the servo driver 111 converts the tracking actuator in the optical pickup 102 according to the tracking drive signal. Drive it.

As described above, according to the method of recording and reproducing an optical recording medium according to the present invention, a fixed DC offset value is held in a header section existing when switching a land / groove track, or a tracking error value of the same track section is used. By performing the tracking servo by holding, accurate header detection is performed during land / groove switching, thereby eliminating track slipping and stabilizing the tracking servo, thereby preventing deterioration of recording and reproducing characteristics.

Claims (26)

In the recording and reproducing method of an optical recording medium having a plurality of first and second tracks having different depths in the direction of light incidence, wherein the first track and the second track are alternately present repeatedly; Determining whether to change from the first track to the second track or from the second track to the first track; Holding the servo control signal of the same track as the track to be changed if it is confirmed as the track change section in the step; And performing a tracking servo with a held servo control signal in a header section within the track change section. The method of claim 1, wherein the holding step And holding the average value of the servo control signals detected in a predetermined section of the same track before. delete delete The method of claim 1, wherein the holding step And a servo control signal immediately before the header section is sampled and held in the header section existing in the first track or the second track except the track change section. The servo control signal of claim 1, wherein A recording and reproducing method of an optical recording medium, characterized in that it is a tracking error signal. In the recording and reproducing method of an optical recording medium having a plurality of first and second tracks having different depths in the direction of light incidence, wherein the first track and the second track are alternately present repeatedly; Determining whether to change from the first track to the second track or from the second track to the first track; Holding a preset DC offset voltage when it is determined as a track change section in the step; And performing a tracking servo with a held direct current (DC) offset voltage in a header section within the track change section. The method of claim 7, wherein And a direct current (DC) offset voltage held in the track change section varies depending on whether the change track is a first track or a second track. The method of claim 7, wherein And a direct current (DC) offset voltage held in the track change section is the same regardless of the change track. delete The method of claim 1, wherein the holding step And holding a fixed direct current (DC) offset voltage when it is determined in the step of the track change section. delete delete In the recording and reproducing method of an optical recording medium having a plurality of first and second tracks having different depths in the direction of light incidence, wherein the first track and the second track are alternately present repeatedly; Determining whether to change from the first track to the second track or from the second track to the first track; Performing a tracking servo by holding a first sample value in a header section existing within the track change section; And performing a tracking servo by holding a second sample value different from the first sample value in a header section existing within the section except for the track change section. 15. The method of claim 14, wherein the servo step in the track change section is And holding the servo control signal of the previous track identical to the track to be changed as the first sample value. 15. The method of claim 14, wherein the servo step in the track change section is And holding the average value of the servo control signals detected in a predetermined section of the same track before as the first sample value. 15. The method of claim 14, wherein the servo step in the track change section is And holding the preset DC offset voltage as the first sample value. The method of claim 17, The DC offset voltage is set differently according to whether the change track is the first track or the second track. The method of claim 17, And said direct current (DC) offset voltage is set the same regardless of the change track. 15. The method of claim 14, wherein the servo step outside the track change section is And holding the servo control signal immediately before the header section as a second sample value. A recording and reproducing method of an optical recording medium in which lands and groove tracks having different depths in the light incidence direction are alternately present repeatedly, Checking whether the land track is changed to a groove track or a groove track to a land track; Selecting and holding one of a servo control signal of a previous track identical to the track to be changed and a preset DC offset voltage when the track change period is determined in the step; And performing a tracking servo with a value held in said step in a header section within said track change section. 22. The method of claim 21 wherein the holding step And selecting and holding the DC offset voltage of the preset groove track when it is confirmed that the change is from the land track to the groove track. 22. The method of claim 21 wherein the holding step And when a change is made from the groove track to the land track, selecting and holding the DC offset voltage of the preset land track. 22. The method of claim 21 wherein the holding step And a DC offset voltage selected and held in the track change section is the same regardless of the change track. 22. The method of claim 21 wherein the holding step And when the change is determined from the land track to the groove track, selecting and holding the average value of the servo control signal detected in a predetermined section of the previous groove track. 22. The method of claim 21 wherein the holding step And when the change is determined from the groove track to the land track, selecting and holding the average value of the servo control signal detected in a predetermined section of the previous land track.

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