KR100606712B1 - Apparatus for generating modulation signal in optical recording media - Google Patents

Abstract

SUMMARY OF THE INVENTION The present invention provides a modulation signal generator for forming a stamper which induces a shape capable of improving addressing capability before and after recording in high-speed recording of an optical disc using land pre-pit. It contains the pre-pit sync code bits of the land pre-pits and consists of relative address bits and user data bits, and the length of each foot of the first, second and last feet of the land-pre-pit is LP1. , LP2 and LP3, if the presence of the land prepit and the track pitch of the track is Tp, the land prepit is adjusted to satisfy 2Tp≥LP1> LP2≥LP3, and the modulation of the land prepit above. The signal is a wobble signal together with the width of the land pre-pit modulation pulses, when the widths of the modulation pulses outputting the respective pre-pits P1, P2, and P3 are WP1, WP2, and WP3. When La Pwo the period (Period of wobble) is generated in the land pre-pit modulation signal having a width satisfying the Pwo> WP1> WP2≥WP3.

DVD-R / RW, LPP, Optical Disc

Description

Apparatus for generating modulation signal in optical recording media

1 is a view showing an example of the position and structure of the land pre-pit of the conventional DVD-R / RW

FIG. 2 is a diagram illustrating an example of an LPP signal extracted from a land pre-pit measurement circuit in a conventional DVD-R / RW and displayed in a wobble signal. FIG.

3 is a diagram showing the position of a conventional ECC block structure and land pre-pits;

4 illustrates land pre-pit formation of a DVD-R / RW substrate according to the present invention;

5 is a cross-sectional view including the land pre-pit shape of the DVD-R / RW substrate according to the present invention.

6 is a view showing the land pre-pit shape of the DVD-R / RW substrate according to the present invention;

7 illustrates a signal pattern of a conventional DVD-R / RW signal modulator.

8 illustrates a signal pattern of a DVD-R / RW signal modulator according to the present invention.

9 is a diagram showing the configuration of a DVD-R / RW signal modulator according to the present invention;

* Explanation of symbols for main parts of the drawings

100: modulation signal generating unit 110: modulation control unit

120: LPP generator 130: clock control unit

140: wobble generator 150: pulse width controller

160: pulse height adjuster 170: wobble amplitude adjuster

180: wobble phase adjuster 200: LPP signal output unit

300: wobble signal output unit

The present invention relates to an optical recording medium and a modulation signal generator for manufacturing a stamper for inducing the same.

Generally, optical discs capable of recording, erasing, and reproducing information. Grooves are formed in DVD-RAM and DVD-RW so that information is recorded and / or reproduced along a predetermined track. This groove is formed in the manufacture of a stamper for manufacturing a substrate.

In addition, the recordable optical disc must include physical address information in the optical disc structure in order to control the spindle servo operation and generate a clock for recording / reproducing data.

However, the biggest difference between DVD-RAM and DVD-RW is shown in the recording area.

In other words, the DVD-RAM is recorded in both the groove area and the land area, and the area containing the address of each unit is located in the form of a pit in order to locate the information by a certain physical unit.

On the other hand, the DVD-R / RW has both land and groove tracks, but only data is recorded on the groove tracks. The land track includes a physical address by placing a land pre-pit (LPP) and does not include a data pit.

That is, the physical address of the groove track is recorded in the pit form on the land track, and the LPP is recorded in phase with the groove track.

Thus, for DVD-R / RWs that use land pre-pit addressing with wobble with uniform amplitude and one frequency, as DVD recording speeds increase as the recording speed increases gradually. There are a number of issues that arise in the writing.

In particular, the land pre-pit signal level amplitude for addressing after the entire recording and the partial recording is greatly changed according to the recording and reproducing conditions according to the high speed of the disk, whereby BELRa, the address decoding performance after recording, is increased. There are disadvantages.

Therefore, to compensate for this, increasing the length of the land pre-pits increases the interference to the smallest signal (3T signal), and increasing the land pre-pit amplitudes causes distortion of the RF signal. In this case, the distorted signal causes not only asymmetry of the signal waveform but also a problem of deteriorating the parity A error and jitter characteristic which are the most important signal characteristics.

Therefore, there is a need to find a method for improving the addressing capability after recording in the case of the DVD-R / RW system using land pre-pit addressing in high-speed recording.

 In order to achieve this, it is necessary to optimize the stamper of the optical disk, but the conventional modulated signal and the generating device has a disadvantage that the above problem cannot be solved.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and in forming a high speed recording of an optical disc using a land pre-pit, a stamper is formed to induce a shape which can improve addressing capability before and after recording. It is an object of the present invention to provide a modulation signal generator for.

A feature of the modulation signal generator of an optical recording medium according to the present invention for achieving the above object includes a pre-pit sync code bit of land pre-pit and consists of a relative address bit and user data bit. The length of each of the first, second and last feet of the land free pit is referred to as LP1, LP2, LP3, and the presence of the land free pit and the track pitch of the track are Tp. The land pre-pit modulation is adjusted so that LP1 > LP2 > LP3, and the width of the modulation pulses for outputting the respective pre-pits is WP1, WP2, and WP3. When the period of the wobble signal together with the width of the pulse is Pwo, a land pre-pit modulation signal having a width satisfying Pwo> WP1> WP2≥WP3 is generated.

In this case, when the height of each pit is called AP1, AP2, AP3, and the height of the groove is Dg with the presence of the land-free pit, the land pre-pit is adjusted to satisfy Dg≥AP3≥AP2> AP1. The Land Pre-Fit Modulation signal generates a Land Pre-Fit Modulation signal having a level satisfying VP3≥VP2> VP1 when the level of the modulation pulses outputting the respective pre-pits is VP1, VP2, VP3. There are other features.

In addition, the positions of the centers of the land pre-pits in the radial direction with respect to the land pre-pits are RP1, RP2, and RP3. When the track pitch is Tp with the presence of the land pre-pits, | Tp | The land pre-pit can be adjusted so that || RP3 |, | RP2 |, | RP1 | and | RP3 |, | RP2 |, | RP1 | have different values. Amplitude of wobble corresponding to each prepit is AWP1, AWP2, and AWP3, and generates a wobble modulated signal having a level satisfying the difference between AWP1, AWP2, and AWP3. There is a characteristic.

A characteristic of the modulation signal generator of an optical recording medium according to the present invention for achieving the above object is a modulation signal generator for generating a stamper modulation signal of an optical information storage medium, each land-free in the modulation signal A pulse width adjuster for adjusting the width of the pit modulation signal, a pulse height adjuster for adjusting the level of each land pre-pit modulation signal, and a wobble for adjusting the amplitude of the wobble signal by adjusting the position of each land pre-pit. It is configured to include an amplitude regulator, characterized in that for generating a modulated signal having the above characteristics.

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

A preferred embodiment of an apparatus for generating a modulated signal of an optical recording medium according to the present invention will be described below with reference to the accompanying drawings.

Physical address information must be recorded on the groove or land surface of the optical disc in order to control the spindle servo operation or generate a clock for recording / reproducing data. DVD-R / RW In such a recordable optical disc, land pre-pit addressing is used.

In this case, the land pre-pit of the DVD-R / RW is information calculated by a modulator in a mastering process of manufacturing a stamper for guiding a disc, unlike information pit (mark or mark) recorded in a groove during recording. According to this, when recording the groove of the stamper using a laser beam, pits are formed on the land track at the same time.

FIG. 1 is a view showing an example of the position and structure of a land pre-pit of a DVD-R / RW, and FIG. 2 is an example of an LPP signal extracted from a land pre-pit measuring circuit in a DVD-R / RW and shown in a wobble signal. An example is shown.

In the case of the DVD-R / RW, an LPP signal recorded in advance on a land is detected to detect address information indicating a track position, a synchronization signal, and the like.

A DVD-R / RW disc will be described below with respect to the land pre-pit (LPP) position as an embodiment.

In DVD-R / RW discs, recording and reproduction of data is performed in units of ECC (Error Correction Code) blocks. As shown in FIG. 3, one ECC (Error Correction Code) block including user data and error correction information is provided. ) Is composed of 16 physical sectors, and one physical sector is made up of 26 sync frames. In addition, eight wobbles exist in one sync frame.

Here, the wobble is information included in the disc by modulating a predetermined clock. For example, the wobble extraction circuit obtains information on the corresponding position, information about the rotation speed of the disk, and the like.

Land pre-pits exist at positions corresponding to the vertices of these wobbles.

In the case of the odd sync frame in FIG. 1, if there are even sync frames in adjacent tracks, LPP data is recorded in a second sync frame in order to prevent overlapping with the LPP recorded at the start of the adjacent even sync frames.

As shown in FIG. 2, the start position of the even sync frame, that is, the bits of the LPP (b0, b1, b2) carried in the first sync frame is 111, and the LPP carried in the second sync frame of the odd sync frame is 110. . Here, b0, b1, b2 are referred to as sync bits.

Therefore, whether the current sync frame is an even sync frame or an odd sync frame is determined using the sync bits b0, b1, and b2.

That is, if the sync bits b0, b1, b2 are 111, an even sync frame, that is, an even sector in which LPP data is written in an even position, and if the sync bits b0, b1, b2 are 110, an odd sync frame, This is an odd sector in which LPP data is recorded in an odd position.

In the DVD-R / RW, the first sector of each ECC block is always an even sector carrying LPP data in an even sync frame.

In order to obtain general information and address information of the recording medium as well as write strategy information from the land pre-pits, it is necessary to extract a land pre-pit detection signal more than a level that can be measured by the LPP measuring apparatus from the wobble signal.

In addition, such a signal type is a ratio of the maximum minimum value of the land pre-pit amplitude before the recording and the pre-pit amplitude before recording (LPPb <0.28) and the wobble amplitude after recording. There are signal items such as AR (Aperture Ratio, AR> 15%).

Deterioration of the LPP recorded on the land track causes deterioration of the addressing characteristics after recording, that is, the AR and BLERa characteristics. This makes it easier to miss address information after recording from the land pre-pit.

In addition, in the case of high-speed recording, the land pre-pit damage is increased due to the increase of the speed due to the high recording power in addition to the recording rate, the increase in the effective radius of the focused light, and the mechanical problems of the focusing and tracking servo. The degree of deterioration of the prepit is further increased.

Therefore, the structure of the land pre-pits to compensate for this includes the pre-pit sync code bits of the land pre-pits as shown in FIG. 4, and the land pre-pit groups are formed with relative address bits.

In this case, the first pit of the land free pit is called P1, the second pit is called P2, the third pit is called P3, and the length of each pit is In LP1, LP2, and LP3, if the presence of the land prepit and the track pitch of the track are Tp, the land prepit is adjusted to satisfy 2Tp > LP1 &gt; LP2 &gt; LP3.

In addition, when the first pit of the land free pit is called P1, the second pit is called P2, and the third pit is called P3, as shown in FIG. In cross-section, the height of the land free pit and the height of each pit are AP1, AP2, and AP3. When the depth of Groove is Dg with the presence of the land free pit, Dg≥ Create a stamper that can make a DVD-R / RW disc by adjusting the land pre-pit to satisfy AP3≥AP2> AP1, and make a disc to record at high speed.

In the LPP measurement of the disk having the shape, the LPP signal is obtained from the LPP sensing circuit after slicing the wobble signal at the slicing level.

Therefore, the LPP having the above-described shape has a better acquisition of a synchronization signal for identifying the LPP group regardless of the effects of high-speed recording and reproducing, thereby improving the addressing ability after recording, and AR, which is the degree of change of the land pre-pit after recording. Even in the case of high.

Fig. 6 is another view showing the land pre-pit shape of the DVD-R / RW substrate according to the present invention having such a structure.

In addition, the modulation signal for generating a land pre-pit to further solve the above problem is as follows.

FIG. 7 illustrates a signal pattern of a modulated signal generator outputting a conventional DVD-R / RW format. The height of three land pre-pit pulses generated by the modulated signal generator is shown in FIG. We can see that the widths are the same. Therefore, a conventional modulated signal generator for outputting the DVD-R / RW format cannot implement a land pre-pit and a modulated signal for inducing the above problem.

Therefore, in order to solve the above problems, a DVD-R / RW format as shown in FIG. 8, a modulation signal for manufacturing a stamper for outputting the output signal, and a modulation signal generating device thereof must be configured.

9 is a unit diagram of the modulation signal generator according to the present invention.

The structure of the signal modulation device is largely composed of a modulation signal unit for outputting a signal modulated by a laser beam recorder and a generator for generating the modulation signal.

As an example, the DVD-R case includes a wobble output unit 140, 180, 300 for forming a groove of an optical recording medium, and a portion 120, 130, 150, 160, 200 for outputting a modulated signal of a land pre-pit formed in a land portion of the optical recording medium. It is done.

Here, the present invention is applied to a laser beam recorder using two beams, and may be applied to a laser beam recorder using one beam.

As such, the modulated signal generator 100 adjusts the modulated signal of the land pre-pit to implement the above-described features. As shown in FIG. 9, the modulated signal generator 100 controls the entire system of the modulated signal generator. The clock controller 130 generates the synchronization of the generation of the wobble and the land pre-pit under the command of the modulation controller 110.

In addition, the LPP generation unit 120 receives the command from the modulation control unit 110 to generate an LPP modulation signal, and the pulse width is adjusted by the pulse width controller 150 to go through the pulse height controller 160. The level of will change.

Subsequently, the generation of the clock output from the clock control unit 130 and the synchronous generation of the wobble and the land pre-pits are passed through the wobble amplitude controller 170 to accommodate an acoustic optical modulator (AOM) and an acoustic optical deflector (AOM). AOD: Acousto-optic deflector) outputs signals respectively.

In addition, the wobble generator 140 generates a wobble modulated signal having a frequency and a constant level by using communication with the modulation controller 110 and the clock controller 130, and the generated wobble modulated signal is wobbled. Passing the phase adjuster 180, the phase with the land pre-pit is corrected to output a wobble modulated signal to the acoustic optical deflector.

As such, the modulation signal generator for generating a stamper modulated signal of the optical information storage medium according to the present invention includes a pulse width controller 150 for adjusting the width of each land pre-pit modulation signal, and the respective land pre-pit modulation. Pulse height adjuster 160 for adjusting the level of the signal, and finally wobble amplitude adjuster 170 for adjusting the position of each land pre-pit. At this time, the wobble amplitude adjuster 170 is branched from a wobble modulated signal forming a groove of the optical recording medium, and the land pre-pit is positioned by wobble amplitude modulation.

By using a modulation signal generator of an optical recording medium that generates the modulated signal in this way, a stamper is made and a disc is made therein for recording and reproduction.

Such optical storage media, especially DVD-R discs, have a better acquisition of a synchronization signal for identifying the LPP group despite the effects of high-speed recording and playback, thus improving the addressing ability after recording and improving the land pre-pit after recording. Even in the case of AR, the degree of change is obviously high.

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.

As described above, the apparatus for generating a modulated signal of an optical recording medium according to the present invention improves the recording and characteristics of rational address information accurately on an optical recording medium by improving a modulation signal commonly used when recording on a stamper of the optical recording medium. Bring it. Especially in optical discs that use land pre-pit signals for addressing, such as in the case of DVD-R / RW, the variation of the land pre-pit amplitudes for addressing before and after recording may result in higher recording speed and By greatly changing by the reproduction condition, the address decoding performance is reduced and the addressing performance is compensated for, and the interference and the error of the reproduction signal due to the RF signal distortion due to the land pre-pit amplitude are increased.

Claims (4)

It contains the pre-pit sync code bits of the land pre-pits and consists of the relative address bits and the user data bits.The first, second and last feet of the land-pre-pits, respectively, In LP1, LP2 and LP3, if the presence of the land prepit and the track pitch of the track are Tp, the land prepit is adjusted to satisfy 2Tp≥LP1> LP2≥LP3, and the In the modulation signal, the widths of the modulation pulses outputting the respective pre-pits are WP1, WP2, and WP3. When the period of wobble signal is set together with the width of the land pre-pit modulation pulses, Pwo> WP1> And a land pre-pit modulated signal having a width satisfying WP2 &gt; WP3. The method of claim 1, When the height of each pit is called AP1, AP2, AP3, and the height of the groove is Dg with the presence of the land-free pit, the land pre-pit is adjusted so as to satisfy Dg≥AP3≥AP2> AP1, and the land described above. The modulated signal of the pre-pit generates a land pre-pit modulated signal having a level satisfying VP3 > VP2 &gt; VP1 when the levels of the modulation pulses outputting the respective pre-pits are VP1, VP2, VP3. An apparatus for generating a modulated signal of an optical recording medium. The method of claim 1, The positions of the centers of the land prepits in the radial direction with respect to the land prepits are RP1, RP2, and RP3. When the track pitch is Tp with the presence of the land prepits, | Tp |> | RP3 |, | RP2 |, | RP1 | and | RP3 |, | RP2 |, | RP1 | can be adjusted so that the land pre-pits have different values, and each of which is synchronized with the modulation signal of said land pre-pit. Amplitude of wobble corresponding to the pre-fit of AWP1, AWP2, and AWP3 is characterized by generating a wobble modulated signal having a level satisfying the difference between AWP1, AWP2, and AWP3. Apparatus for generating a modulated signal of an optical recording medium. In the modulation signal generator for generating a stamper modulated signal of the optical information storage medium, A pulse width adjuster for adjusting the width of each land pre-pit modulated signal in the modulated signal; A pulse height adjuster for adjusting a level of each land pre-pit modulated signal; And a wobble amplitude adjuster for adjusting the amplitude of the wobble signal by adjusting the position of each land pre-pit, thereby generating a modulated signal having the features of claim 1. Device.

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