KR20000074147A - Method for recording/playing of optical recording medium - Google Patents

Abstract

PURPOSE: A recording/reproducing method of an optical recorder is provided to hold a fixed DC offset voltage at a header section in a land/groove track switching, and thus stably performing a tracking servo. CONSTITUTION: A recording/reproducing method of an optical recorder having a plurality of first and second tracks comprises the steps of: identifying whether or not the fist track is changed into the second track; holding a servo control signal of the previous second track as a servo control signal of the changed second track when the track change is identified; and performing a tracking servo by the holden servo control signal. Also, a record reproducing method of an optical recorder having a plurality of first and second track comprises the steps of: identifying whether or not the fist track is changed into the second track, or the second track is changed into the first track; holding a fixed DC offset voltage as the servo control signal of the changed track; and then performing a tracking servo by the holden servo control signal.

Description

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

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, that is, 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 also 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 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 by the depth difference between the land and the groove, as shown in FIG. 3, the tracking error signal bounces as much as the land offset 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 The present invention has been made to solve the above problems, and an object of the present invention is to provide a recording and reproducing method of 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. have.

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.

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: 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

According to an aspect of the present invention, there is provided a method of recording and reproducing an optical recording medium, the method 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 of the optical recording medium which is present in this alternating manner is changed; and when the track change section is confirmed in the step, the servo control signal of the same second track is changed. And holding a servo control signal of the second track, and performing a tracking servo with the held servo control signal.

The hold step is characterized by holding the servo control signal of the same second track previously during the header period present in the track change section.

The holding step is characterized in that when changing from the second track to the first track, the servo control signal of the same first track is held by the servo control signal of the first track to be changed.

The holding step is characterized by holding the servo control signal immediately before the header section in the header section existing in the first track or the second track.

The servo control signal of the step is characterized in that the tracking error signal.

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 recording medium is changed from the first track to the second track or from the second track to the first track, and if the track change section is confirmed at this step, a servo of the track that changes a fixed DC offset voltage. And holding a control signal and performing a tracking servo with the held servo control signal.

The holding step is characterized in that the DC offset voltage held in the track change section varies depending on whether the change track is the first or second track.

The holding step is characterized in that the DC offset voltage held in the track change section is the same regardless of the change track.

The first track is a land track, the second track is a groove track, or vice versa.

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 tracking servo by holding a fixed DC offset value in the header section existing during land / groove track switching, or by sampling / 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. An optical pickup 102 for recording and reproducing information on 101, an RF and servo error generator 103 for generating RF and servo error signals from electrical signals output from the optical pickup 102, and a header section. A sample / hold unit 104 for holding the determined sample value, a groove offset unit 105 for adjusting a DC offset of the tracking error signal input through the sample / hold unit 104, and the sample / hold unit 104. Selects the output of the groove offset unit 105 or the output of the land offset unit 106 by the land offset unit 106 to adjust the DC offset after inverting the tracking error signal input through Land / groove switch to output When the header section is detected, the header mask signal is output to the sample / hold unit 104, and the land / groove is determined from the signal of the header area and output to the land / groove switching unit 107. 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, and the land / groove. The servo controller 110 converts a signal output through the switching unit 107 into a tracking drive signal, and drives the tracking actuator in the optical pickup 102 according to the tracking drive signal output from the servo controller 110 to track the drive. It consists of a servo drive part 111 which performs a 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 from each photo detector is output to the RF and servo error generator 103.

The RF and servo error generator 103 detects an RF signal for data reproduction, a focus error signal FE for servo control, a tracking error signal TE, and the like from the electrical signal output from the photo detector.

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 DC offset voltage (for example, 2V), so that the header shown in FIG. The increase in the track error after passing the 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.

That is, since the DC offset of the land / groove is different according to the land / groove depth difference, the DC offset voltage of the groove may be held when switching from land to groove, and the DC offset voltage of the land may be held when switching from groove to land. have.

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 when the land / groove track is switched.

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 the land / groove track is switched.

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. At this time, 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 is the DC offset of the held value or the value of the tracking error. After adjusting to fit the land, invert it.

In addition, the land / groove switching unit 107 may be DC offset adjusted by the groove offset unit 105 or DC offset by the land offset unit 106 according to the determination signal of the land / groove determination unit 108. The butt 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 a previous track section is held. By performing the tracking servo, 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 (10)

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 a second track; Holding the servo control signal of a previously identical second track to the servo control signal of the second track to be changed if it is identified as the track change section in the step; And performing a tracking servo with the held servo control signal. The method of claim 1, wherein the holding step A method of recording and reproducing an optical recording medium, characterized by holding a value obtained by averaging the servo control signal of the same second track for a predetermined period. The method of claim 1, wherein the holding step And holding the servo control signal of the same second track previously held during the header section existing in the track change section. The method of claim 1, wherein the holding step And upon changing from the second track to the first track, the servo control signal of the same first track is held by the servo control signal of the first track to be changed. The method of claim 1, wherein the holding step And a servo control signal immediately before the header section in the header section existing in the first track or the second track. 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 fixed DC offset voltage as a servo control signal of a track to be changed if it is determined as a track change section in the step; And performing a tracking servo with the held servo control signal. 8. The method of claim 7, wherein said holding step And the DC offset voltage held in the track change section varies depending on whether the change track is the first or second track. 8. The method of claim 7, wherein said holding step And the DC offset voltage held in the track change section is the same regardless of the change track. 8. The method of claim 7, wherein said holding step And holding and holding the DC offset voltage determined during the header section existing in the track change section.