KR20020041653A - Method for generating optimized record power of optical record medium record/player - Google Patents

Abstract

PURPOSE: A method of generating an optimum recording power of a recording player of an optical recording medium is provided to search an area for performing an OPC(Optimum Power Control), and to record a preset recording pattern as changing a recording power, then to search an area where the recording pattern is recorded to reproduce recorded data. CONSTITUTION: If data is inputted, an OPC controller decides an OPC operation(201). A laser power controller outputs a recording power to an LD driver under control of the OPC controller(202). The OPC controller searches a position to perform the OPC operation on a non-recording area of a PCA(Power Calibration Area)(203). If the searching is completed(204), the LD driver changes recording power of each sector to record 3T as 16-stage recording power during a searched 1 ECC block(205). If the recording is completed(206), the LD driver measures jitters of each recording power as reproducing the 1 ECC block or 1 sector(207). The OPC controller decides an optimum recording power by using jitter values, and stores the power(208). The OPC controller records data on a user data area with the decided optimum recording power(209).

Description

Method for generating optimized record power of optical record medium record player {Method for generating optimized record power of optical record medium record / player}

The present invention relates to a system for recording and reproducing data on an optical disc, and more particularly to a method for generating an optimal recording power for recording data on a disc.

As the storage capacity of existing CD-ROM titles has reached the limit, digital versatile discs (DVDs) have been in the spotlight as new storage media. The DVD is not much different from the CD in terms of implementation. That is, the data is recognized on the same principle as the CD for recognizing the data of 0 and 1 by the difference in the amount of light reflected by the laser. The difference is that the data storage is smaller than the CD.

These CDs and DVDs are classified into three types according to their functions and uses: read-only ROM, write-once worm type, and rewritable rewritable type.

The ROM type optical disc may include a compact disc read only memory (CD-ROM) and a digital versatile disc read only memory (DVD-ROM), and a warm optical recording medium may be written once. Recordable Compact Discs (CD-Rs) and Recordable Digital Versatile Discs (DVD-Rs). In addition, freely rewritable optical discs include a rewritable compact disc (CD-RW) and a rewritable digital versatile disc (DVD-RW, DVD-RAM, DVD + RW). have.

The optical recording and reproducing apparatus for recording and reproducing the CD-based optical disc and the DVD-based optical disc records information on the optical disc by irradiating a light beam of relatively large energy that can change the physical properties of the information recording layer and record the information on the optical disc. The information is reproduced from the optical disk using a light beam of small energy that does not change the material properties of the layer. That is, during recording, information is normally recorded by driving the laser diode LD at a relatively high recording power to form pits on the optical disk. In this case, forming a pit by a predetermined length on the disk is referred to as a write strategy.

At this time, the laser light is incident on the opposite side of the reflective surface with a pit. Therefore, the pit appears as a projection when viewed from the laser incident side.

The pit has a width of 0.4 to 0.6 mu m, and the length of one pit and the interval between the pit and the pit are divided into 3T to 11T for CD series and 3T to 14T for DVD series. Here, T means the length of one clock pulse, 3T means three clock pulses, and 11T corresponds to the length of 11 clock pulses.

In this case, when recording information on a recordable optical disc such as the CD-R / RW, the optical disc recording and reproducing apparatus performs an Optimal Power Control (OPC) process for selecting a recording power suitable for the disc. have. To this end, the recordable optical disc includes a PCA (Power Calibration Area), which is a test area for determining recording power, in an unused area of the innermost portion.

FIG. 1A is a layout diagram of a recording area of a typical CD-R / CD-RW disc, which is largely divided into a clamping area 10 clamped by a clamper and a recording area 20 in which data is recorded and reproduced. . The recording area 20 is again a power calibration area (PCA) 22 for determining an appropriate laser power for data to be recorded in the radial direction, and a program memory area having information on data being recorded. area (PMA) 24, a lead-in area 26 for recording information on recorded data, a user data area 28 where user data is recorded, and a lead-out located at the outermost circumference A lead out area 30 is included.

The PCA 22 is divided into a test area for testing laser power when performing OPC and a count area for recording the number of tests, that is, the number of repeated recordings, as shown in FIG. It is divided into partitions. Therefore, the test can be performed up to 100 times, and if more than 100 times, recording is no longer possible even if the recording space remains.

At this time, one partition of the test area is composed of 15 sectors, as shown in FIG. 1C, and one partition, that is, 15 sectors is used in one test write. That is, if one OPC is performed, test writing can be performed with 15 laser outputs for 15 sectors.

To this end, the optical disc recording / reproducing apparatus first reads the Absolute Time In Pregroove (ATIP) information recorded on the disc and divides the recording power into 15 steps based on the reference power recommended by the disc manufacturer to test the area of the PCA 22. Write a random or nT EFM (Eight to Fourteen Modulation) signal. Then, this is reproduced, and when the peak hold and the bottom hold of the reproduced signal are properly balanced, it is assumed that the appropriate recording power is assumed, and this value is used for recording to the user area 28. Record the data. The reference power is encoded in special information of ATIP in the lead-in area, and has a wavelength of 785 nm at a single speed.

That is, after recording random data or nT EFM signal in the test area and reproducing, the peaks of the positive and negative parts of the Hi-Fi (HF) signals for each recording power are examined as shown in the waveform of FIG. Value is '0', that is, the power that becomes symmetrical is determined as the optimal recording power.

However, since it is difficult to find a recording power that is exactly '0', the CD-R / RW specification recommends that the recording power having a parameter β of about 0.04 (that is, 0.4%) is determined as the optimal recording power. have. If there are a large number of recording powers included in the asymmetric allowable range, the recording power having the smallest degree of asymmetry is determined as the optimal recording power.

3 (a) to 3 (c) are waveform diagrams when AC-coupled RF signals reproduced in the test area are shown, in which 3T and 14T are recorded with the same recording power during one sector. .

FIG. 3A is an asymmetric waveform that appears when the power P recorded in the test area is smaller than the disk optimal power Po (P << Po), and FIG. 3C shows the test area. This is an asymmetric waveform (P >> Po) that appears when the power P recorded in the graph is larger than the disk proper power Po. 3B illustrates a symmetric waveform P that appears when the power P recorded in the test area and the disk proper power Po are correctly matched. Po). That is, if data is recorded in the test area at the optimal recording power, the AC-coupled RF signal waveform is symmetrical with respect to the reference level Vref as shown in FIG.

Therefore, if the power recorded in the test area is equal to that of Fig. 3B, the parameter β ( ) Is nearly zero.

At this time, there may be various methods for detecting the optimal recording power. The above-mentioned method is called an asymmetry method, and is generally applied to the case of CD-R.

On the other hand, CD-R and CD-RW differ in recording materials. In the case of CD-RW, asymmetry is worse than that of CD-R. In addition, in the case of CD-RW, it is difficult to use high power because it has to ensure repeat recording characteristics. Therefore, in the case of the CD-RW, the modulation degree method shown in Figs. 4 and 5 is generally applied as a method for detecting the optimum recording power.

That is, the random data or the nT EFM signal is recorded in the test area, and then the amount of light at the peak level and the level at the bottom level of the RF signal reflected from the test area is checked as shown in FIG. Then, the checked amount of light is calculated by the following Equation 1 to obtain a modulation amplitude (m). And, as shown in Figure 5 modulation curve and gamma ( ) Is used to determine the optimum recording power.

Where the gamma ( ) Curve is a normalized slope of the function m (Pw), and is expressed as a modulation degree change amount and a recording power change amount as shown in Equation 2 below, and Pw is the recording power recorded in the test area.

At this time, the optimal recording power Po is determined by the gamma target predetermined in the gamma curve. The multiplication factor p is determined by multiplying the write power Pt corresponding to the value of. Where The value and multiplication factor, like the reference power described above, are predetermined at the time of disc manufacture and are encoded in the special information of the ATIP in the lead-in area, and may vary by disc type and manufacturer.

On the other hand, even a DVD-based disc such as a DVD-R / DVD-RW has a PCA area like a CD-R / RW for optimal recording. However, since there is no provision for how to use it, there is a need for a method of finding an optimal recording power in the DVD-R / RW.

At this time, the DVD-R / RW has both land and groove signal tracks, but records data only on the groove signal tracks. In other words, the DVD-R / RW pre-pits the land track to record position information on the groove track, and does not record data on the land track. At this time, the positional information on the land track is referred to as land-pre-pit (hereinafter referred to as LPP). That is, information on the physical address of the groove track is previously recorded in the land track in the form of a pit. In addition, location information such as the address information may be recorded in a wobbling shape along the track boundary.

Here, the wobble is a control signal by changing the light beam of the laser by supplying information to be applied to the disk by modulating a constant clock, for example, information of the corresponding position, information about the rotation speed of the disk, and the like to the power of the laser diode. Is recorded at the boundary of the track.

FIG. 6 shows an example of the PCA area of the DVD-R / RW. FIG. 6A shows an example of the LPP structure of the DVD-R / RW. FIG. 6B shows a tracking error detected by the push-pull method in the DVD-R / RW. An example of the LPP signal shown in the signal is shown. In the case of the DVD-R / RW, an LPP signal recorded in advance on the land is detected to detect address information indicating a track position, a synchronization signal, and the like.

At this time, in the case of the DVD-R / RW, recording and reproduction of data is made in units of ECC blocks, that is, in units of 16 sectors. In addition, each physical sector consists of 26 sync frames. In this case, each physical sector has LPP data written in an even sync frame (eg, 0, 2, 4, 6, ...) as shown in FIG. 7A, or an odd sync frame (eg, 1,3, etc.) as shown in FIG. 7B. LPP data is recorded in 5, 7, ...). In addition, 39 bits of LPP data are recorded in one physical sector.

Here, for convenience of description, the case where the LPP data is recorded in the even sync frame is called an even sector, and the case where the LPP data is recorded in the odd sync frame is called an odd sector. In addition, the even sync frame and the even position are used in the same sense, and the odd sync frame and the odd position are used in the same sense.

As shown in FIG. 6B, the LPP data b0b1b2 on the start position of the even sector, that is, the first sync frame, is 111, and the LPP data b0b1b2 on the second sync frame of the odd sector is 110. In the case of the odd sector, LPP data is recorded in a second sync frame in order to prevent overlapping with LPP data recorded at the start position of the even sector. Here, b0b1b2 is referred to as a sync bit for convenience of description.

Therefore, whether the current sector is an even sector or an odd sector can be determined using the sync bits b0, b1, and b2. That is, when the sync bits b0, b1, and b2 are 111, an even sector in which LPP data is recorded in an even sync frame, that is, an even position, and 110, an odd sector in which LPP data is recorded in an odd sync frame, that is, an odd position.

In addition, the first sector of each ECC block is an even sector in which LPP data is always carried in an even sync frame.

By the way, in the case of a DVD-based disc having the above characteristics, such as a DVD-R / RW, the PCA area has a PCA area such as a CD-R / RW for optimal recording, but there is no provision to use it. Therefore, there is a need for a method of finding an optimal recording power in the DVD-R / RW.

It is an object of the present invention to provide a method for generating an optimum recording power using jitter.

Another object of the present invention is to provide a method for generating an optimal recording power by detecting the start position of an odd sector by sector synchronization when performing OPC sector by sector.

1A is a view showing the structure of a conventional CD-R / RW disc

1B and 1C show the format of the PCA on the disk of FIG. 1A

2 is a waveform diagram defining beta (β), which is an asymmetric characteristic in a typical CD-R disc

3 (a) to 3 (c) are waveform diagrams showing AC-coupled hi-fi signals by recording power in the CD-R disc of FIG.

4 is a waveform diagram illustrating modulation characteristics in a typical CD-R disc.

FIG. 5 is a graph illustrating a gamma curve using the modulation rate change rate and the recording power change rate of FIG. 4.

6A is a view showing an LPP structure in a general DVD-R / RW disc

FIG. 6B shows an example of an LPP signal in the DVD-R / RW disc of FIG. 6A

7A is a general diagram illustrating an example of a sector in which LPP data is recorded in an even position;

7B is a general diagram showing an example of a sector in which LPP data is recorded at an odd position;

8 is a block diagram for determining an optimum recording power in the optical recording / reproducing player according to the present invention.

FIG. 9 is a flowchart illustrating an example of determining an optimum recording power using a jitter characteristic in the optical recorder of FIG. 8. FIG.

10A to 10C are waveform diagrams showing an example of general jitter detection.

11A is a timing diagram of the present invention showing an example in which the recording power is changed in 16 steps during one ECC block when performing OPC in units of one ECC block.

FIG. 11B is a timing diagram illustrating an example of the jitter window generated in FIG. 11A.

FIG. 11C is a timing diagram of the present invention showing an example in which the recording power changes to 13 steps P0 to P12 during one sector when performing OPC in units of one sector.

FIG. 11D is a timing diagram showing an example of the jitter window generated in FIG. 11C.

12 (a) and 12 (b) are graphs of the present invention showing a reproduction jitter graph for recording power when OPC is performed with one ECC block and an optimum recording power determination process at this time.

Explanation of symbols for main parts of the drawings

101: RF signal generation unit 102: RF signal processing unit

103: jitter detector 103-1: equalizer

103-2: automatic gain control unit 103-3: jitter measurement unit

104: wobble and LPP detection section 105: encoding section

106: OPC control unit 107: laser power control unit

108: LD drive unit

In accordance with an aspect of the present invention, there is provided a method of generating an optimal recording power, the method comprising: generating a recording pattern for performing an OPC, searching an area for performing the OPC, and then applying an optical recording medium to the searched area. Recording the recording pattern while varying the recording power based on the recorded reference recording power; searching the area in which the recording pattern is recorded to reproduce the recorded data; and from the jitter characteristic of the reproduction signal for each recording power, And determining the optimum recording power, and recording the user data inputted into the user data area on the optical recording medium which is predetermined by the determined optimal recording power.

In this step, the OPC is performed in units of ECC blocks, which are data recording and reproducing units, and the recording power is changed for each sector constituting the ECC block.

In this step, the OPC is performed in units of sectors, and the recording power is changed for each N (N is a natural number) sync frame constituting a sector.

If the OPC is performed in units of sectors, the method may further include synchronizing sectors of the test area.

The sector synchronizing step includes detecting a signal that is wobbling on a signal track, outputting a phase-synchronized wobble signal by applying a phase locked loop (PLL) to the wobbled signal, and outputting the phase locked (PLL) signal; Counting the wobble signal) and detecting the start position of each sector.

The determining of the optimal recording power may include generating an RF signal by using an electrical signal having an amount of light reflected at a recording position of each recording power for each recording power, biasing the RF signal to a reference voltage after AC coupling the RF signal. And detecting the jitter characteristics of the RF signal biased to the reference voltage after the AC coupling for each recording power, and determining the recording power within the allowable jitter range as the optimal recording power. do.

The determining of the optimum recording power is characterized in that if the optical recording medium is an optical recording medium that can be recorded once, the recording power with the minimum jitter is determined as the optimal recording power.

The determining of the optimum recording power is characterized in that if the optical recording medium is an optical recording medium which can be repeatedly recorded, the recording power having the higher jitter within the allowable jitter range is determined as the optimal recording power.

The determining of the optimal recording power may be performed by differentiating the jitter characteristic of each recording power when the optical recording medium is a repeatable recording optical recording medium. It is characterized by determining the recording power of the position where?) Is smaller than the experimental value K as the optimum recording power.

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.

Fig. 8 is a block diagram showing the construction of an optical disc recording / reproducing apparatus according to the present invention, showing OPC related blocks.

Referring to FIG. 8, an RF signal generator 101 for generating an RF signal by combining an electrical signal of an amount of reflected light output from an optical pickup (not shown), and converting the RF signal into an AC coupling and a reference voltage Vref. A push-pull combination of an RF signal processor 102 for biasing, a jitter detector 103 for detecting jitter from an RF signal biased to the reference voltage Vref after the AC coupling, and an electrical signal of the amount of reflected light output from the optical pickup A signal is generated, a PLL is applied to a wobble clock of the wobble and LPP detection unit 104 and the wobble and LPP detection unit 104 to detect a wobble clock and LPP data from the push-pull signal, and decodes the LPP data and writes to a disc. A recording pattern is generated, and an encoder 105 for outputting a jitter window signal to the jitter detector 103 and the jitter detected by the jitter detector 103 are input to control OPC to optimally record. An OPC control unit 106 for determining power, a laser power control unit 107 for controlling laser power under the control of the OPC control unit 106, and a recording pattern output from the encoding unit 105 are stored in the laser power control unit ( And a laser diode (LD) driver 108 for recording with the recording power provided by 107.

9 is an operation flowchart of the OPC control unit 106 for generating the optimum recording power according to the present invention. The OPC control unit 106 controls the OPC so as to record at the optimum recording power during recording. To this end, in order to detect the optimum recording power from a certain recorded pattern, jitter is obtained for each recording power applied during recording, and then the jitter for each recording power is stored in the storage area. The optimum recording power is then determined by comparing the amount of jitter for each recording power stored.

In particular, when performing recording for the OPC, a recording pattern and a recording power level are planned, and recording is performed in the test area of the PCA of the disc according to the method.

In the present invention configured as described above, the OPC may be performed in units of 1 ECC block (= 16 sectors) or in units of 1 sector, which is controlled by the OPC control unit 106. In this case, when performing OPC in units of 1 ECC block, the statistical degree of jitter may be increased.

In addition, when OPC is performed in units of 1 sector, even if a recordable area remains, the PCA which cannot record due to the full test area can be overcome.

Here, jitter means that the length function is analogically changed for the same T, and digitally, it means that the phase is different even though it is the same T.

10 (a) to 10 (c) show examples of a general jitter detection method and obtain jitter as shown in Equation 3 below.

If OPC is performed in units of one ECC block, the recording power is different for each sector, and data input at the same recording power is recorded in each sector. That is, during one OPC, data input at 16 recording power levels is recorded during one ECC block of the test area of the PCA.

On the other hand, if OPC is performed in units of sectors, data input at various stages of recording power during one sector is recorded. That is, one OPC is performed for one sector, and the input data is recorded while the recording power is changed in several steps during that sector. Here, since one sector is composed of 26 sync frames, if OPC is performed at 13 write powers when performing OPC on a sector basis, the write power is changed every 2 sync frames.

In addition, the recording pattern can be recorded by setting to a single recording pattern of random data or nT / nT. In particular, when performing OPC in units of one ECC block, a single recording pattern of random data or nT / nT is set, and in units of sectors, nT / nT is set. At this time, when a single recording pattern of nT / nT is set as an OPC recording pattern, a short T such as 3T or 4T is used. This is to ensure the number of samples in the jitter measurement of nT.

That is, when an optical disc, for example, a DVD-R / RW is inserted or data for recording is input, the OPC control unit 106 determines by performing OPC (step 201).

At this time, the wobble and LPP detection unit 104 generates a tracking error signal by combining the electrical signals (a, b, c, d) of the amount of reflected light output from the photo detector in the optical pickup by a push-pull method, and then generates a tracking error signal from the tracking error signal. Detect wobble clock and LPP signals. The wobble clock and the LPP signal are output to the LPP decoder and the wobble PLL unit 105-1 of the encoder 105.

The LPP decoder and wobble PLL section 105-1 generates a high frequency clock for use in recording by applying a PLL to the wobble clock. Then, the high frequency clock is appropriately divided to generate a wobble clock on which the PLL is applied, and then output to the OPC control unit 106, the DVD encoder 105-2, and the jitter measurement unit 103-3. In addition, the PLL decodes the LPP signal using the wobble clock, detects a physical address, a synchronization pattern, and the like necessary for the OPC, and outputs the same to the OPC controller 106.

On the other hand, the DVD encoder 105-2 encodes data provided for recording by the personal computer (PC) or the OPC control unit 106, and outputs the data to the recording pattern generation unit 105-3. The recording pattern generator 105-3 generates a recording pattern from the encoded data according to the write stretch required for each disc.

In particular, when performing the OPC, the DVD encoder 105-2 generates a special pattern for the OPC (for example, random data or nT / nT if the OPC performance is in units of 1 ECC block, and nT / nT if the sector is in units of 1). Alternatively, the recording pattern generating unit 105-3 may generate the data directly.

The recording pattern generated by the recording pattern generator 105-3 is output to the LD driver 108 as an LD drive signal. The LD driver 108 converts the LD driving voltage into an LD driving current and then amplifies the LD driving voltage to drive the LD in the optical pickup. At this time, the recording power of the LD driving unit 108 is made through the laser power control unit 107 under the control of the OPC control unit 106.

That is, if it is determined in step 201 that the OPC is performed, the encoding unit 105 generates nT / nT or random data under the control of the OPC control unit 106 and then LD through the recording pattern generation unit 105-3. Output to the driver 108.

In addition, the OPC control unit 106 reads the reference power recommended by the disc manufacturer from the ATIP information of the lead-in area, divides the recording power into several stages based on the reference power, and sequentially lasers the recording power of each stage. Output to the power control unit 107. For example, if the OPC is performed in units of 1 ECC block, the recording power is divided into 16 stages based on the reference recording power, and if it is performed in units of 1 sector, it is divided into 13 stages. The laser power control unit 107 outputs the corresponding recording power to the LD drive unit 108 under the control of the OPC control unit 106 (step 202).

In addition, the OPC control unit 106 searches for a position to perform OPC in the unrecorded area of the PCA by using the LPP information and the wobble clock information provided by the encoding unit 105 (step 203). Here, if the OPC is performed in units of 1 ECC block, the position to be searched will be the start position of the ECC block, and if it is performed in units of 1 sector, it will be the start position of the sector in the ECC block.

If OPC is performed in units of 1 sector, the start position of an even sector or an odd sector on which OPC is to be performed by sector synchronization can be found.

That is, in the present invention, when performing OPC on a sector basis in a DVD-R / RW, sector synchronization using wobble is performed to find the start position of each physical sector, in particular, the start position of the odd sector.

In the case of an even sector, since the sync code is recorded in the first sync frame, the corresponding recording pattern can be recorded from the start of the even sector. In the case of the odd sector, the sync code is recorded in the second sync frame. This is because in order to perform OPC in the sector, the first sync frame of the odd sector, that is, the start position must be found. That is, one sector is composed of 26 sync frames, but since there is no marking, the start position cannot be found in the odd sector.

Accordingly, in the present invention, the start position of each sector is synchronized by counting the PLL wobble clock.

That is, one physical sector consists of 26 sync frames, and the number of PLL wobble clocks is 208. Therefore, one sync frame is composed of eight wobble clocks (= 208/26).

Accordingly, the wobble clock is counted to detect the start position of the even sector and the start position of the odd sector. To do this, first, a count start time of the wobble clock is determined.

In other words, since the DVD-R / RW performs recording and reproduction of data in units of ECC blocks, and the first sector of each ECC block is always recorded in an even sector, that is, in an even position, the first sector of the ECC block according to the present invention. The start position of the sector may be determined as the count start time and the count may be started, or the count may be started from the detection position of the even frame sync signal among the LPP sync signals. Then, the start positions of the even sector and the odd sector are detected by the number of wobble clocks counted.

At this time, the number of counts at the start position of the odd sector varies according to the division ratio of the wobble clock divided by the LPP decoder and the wobble PLL unit 105-1.

In the present invention, as an embodiment, it is assumed that the wobble clock is divided by eight at the start position of the even sector at which the count starts.

Then, the eight-minute wobble clock toggles high / low every sync frame. This is because one sync frame consists of eight wobble clocks. That is, if the wobble clock is divided into eight by the LPP decoder and the wobble PLL unit 105-1, the high / low cycle is repeated for each sync frame, and thus the number of wobble clocks counted in one sector is thirteen. In this case, when the divided eight wobble clock is high, an even sync frame (eg, 0, 2, 4, ...) of the corresponding sector is used. When the divided wobble clock is low, an odd sync frame of the corresponding sector ( 1,3,5, ...).

For example, if the count starts at the start position of the even sector where the even frame sync signal is detected, the OPC control unit 106 moves the rising edge of the eighth divided wobble clock to the start position of the next odd sector. Determine. By repeating this process, not only the even sector and the odd sector can be easily distinguished from each ECC block, but also the starting positions of the even sector and the odd sector can be accurately detected.

As described above, when the sector synchronization is performed, even when the LPP data is an odd sector recorded in the odd sync frame, the start position can be accurately detected, and thus the OPC can be performed in the sector sector.

At this time, the search of the position to perform the OPC may be performed from the inner circumference to the outer circumference or the outer circumference. If OPC is sequentially performed from the innermost circumference to the outer circumferential side, it is advantageous to record from low power to high power for the sector mark on which the OPC is performed. However, when OPC is sequentially performed from the outer circumference side to the inner circumference side of the PCA area as in the conventional CD, it is advantageous to record from high power to low power for the sector mark on which the OPC is performed.

In this way, it is possible to reliably distinguish between the area where the recording pattern is recorded and the area where the recording pattern is not performed.

When the search of the position to perform the OPC is completed (step 204), the OPC is performed at the position.

For example, assuming that the OPC is performed in units of one ECC block, and the recording pattern is a single recording pattern of 3T / 3T, the LD driver 108 searches for the search performed in the step by changing the recording power for each sector. 3T is recorded with 16 recording powers during one ECC block (step 205). That is, after the pit and the blank are recorded at 3T with the same recording power for one sector, the process of recording the pit and the blank at 3T with the other recording power is repeated for one ECC block in the next sector.

On the other hand, assuming that the OPC is performed in units of 1 sector, the recording pattern is 3T / 3T, and the recording power is divided into 13 stages, the LD driver 108 changes the recording power every two sync frames. During the sector searched in the step, 3T is recorded at the writing power of 13 steps (step 205). That is, pits and blanks are recorded at 3T during two sync frames recorded with the same recording power, and this process is performed sequentially for 13 stages of recording power for one sector.

Then, if it is determined that recording is completed (step 206), jitter is measured for each recording power while reproducing one ECC block or one sector on which OPC data is recorded (step 207).

That is, the RF signal generator 101 generates an RF signal by combining (a + b + c + d) the electrical signals a, b, c, and d of the amount of light reflected from the ECC block or sector. Output to RF signal processing unit 102. The RF signal processor 102 AC-couples the RF signal through the capacitance 102-1 and biases the RF signal with a reference voltage in the buffer 102-2 to output the jitter detector 103. Then, the AC component of the RF signal is loaded around the reference voltage Vref.

The equalizer 103-1 of the jitter detector 103 equalizes the RF signal biased to the reference voltage Vref after AC coupling, and outputs the equalized RF signal to the auto gain controller 103-2. The AGC 103-2 automatically adjusts the gain of the equalized RF signal and then outputs it to the jitter measuring unit 103-3. That is, the RF signal biased to the reference voltage Vref after the AC coupling is digitized by passing through the equalizer 103-1 and the AGC 103-2. In this case, the degree of freedom of the slice is increased by using the AGC.

The jitter measurement unit 103-3 outputs a portion of the phase difference in the output of the AGC 103-2 to the OPC control unit 106 during the jitter window output from the encoding unit 105, and the OPC control unit 106. ) Continues to accumulate the jitter during the jitter window to detect jitter for one write power. This process is repeated for each recording power. That is, when the OPC is performed in one ECC block unit, the above-described process is performed 16 times, and when the recording power is changed every two sync frames while performing the OPC in one sector unit, the above-described process is performed 13 times.

At this time, the basic clock of the jitter measurement used in the jitter measurement unit 103-3 is based on the PLL wobble clock. The PLL wobble clock is input from the encoder 105. This is to reproduce the same as the recording conditions.

In addition, the jitter measuring unit 103-3 may detect jitter in various ways, and may detect jitter by applying Equation 3 described above as an embodiment. Since this invention is not an invention regarding jitter detection, jitter detection can use a well-known technique as it is.

FIG. 11A illustrates an example in which the recording power is changed in 16 steps P0 to P15 during one ECC block when performing OPC in units of one ECC block, and FIG. When performing OPC, an example is shown in which the recording power changes in 13 steps P0 to P12 for one sector. Here, the recording power of step 16 or the recording power of step 13 is divided and stored based on the reference power recorded at the time of disc manufacture.

In particular, when OPC is performed in units of one ECC block as shown in FIG. 11A, a single recording pattern of random data or nT / nT is recorded in each sector according to a preset recording power level. In the case of recording with random data as in the former case, after measuring the integrated jitter, the optimum recording power is determined according to a predetermined rule. On the other hand, in the case of recording in a single recording pattern of nT / nT as in the latter, the single recording jitter is measured and then the optimum recording power is determined according to a predetermined rule.

In addition, when OPC is performed in units of 1 sector as shown in FIG. 11C, a single recording pattern of nT / nT is recorded in a sync frame of a corresponding sector according to each recording power level. In one embodiment, 3T / 3T is recorded. If you are showing.

At this time, a jitter window is generated for each sector when performing OPC in units of one ECC block, and for every sync frame of the same recording power when performing OPC in units of one sector. The jitter window is generated to stably detect jitter. That is, jitter is detected and accumulated only within the jitter window. At this time, the jitter window is generated from the wobble clock PLL by the encoder 105. In other words, the jitter window is generated by the encoder 105 under the control of the OPC control unit 106 and output to the jitter measuring unit 103-3 of the jitter detector 103.

The amount of phase difference, i.e., the length is changed, becomes the jitter amount, and the OPC control unit 106 performs a process of accumulating the jitter amount for each recording power during the jitter detection period, that is, the jitter window signal is active. Save each.

If OPC is performed in units of 1 ECC block, the jitter window is cleared for 1 or 2 wobble clocks of the start sync frame of the first sector of each ECC block as shown in FIG. Clears the jitter window during one or two wobble clocks at the beginning of the synchronous frame in which the recording power changes as shown in FIG.

When the jitter is obtained for each recording power by this process, the OPC control unit 106 determines the optimal recording power using the jitter value and stores it (step 208). Then, data is recorded in the user data area at the determined optimal recording power (step 209).

12 (a) and 12 (b) show a reproduction jitter graph with respect to recording power when OPC is performed with one ECC block and an optimum recording power determination process at this time. That is, the graph which differentiated FIG. 12 (a) is FIG. 12 (b).

For example, in the case of a write-once disc such as a DVD-R or a CD-R, it is not necessary to secure the repetitive recording characteristic, so that the recording power with the minimum jitter is detected as the optimum recording power Po. . At this time, since the recording power whose jitter becomes exactly 0 is hard to find, the recording power below the jitter determined by the standard or the manufacturer is determined as the optimum recording power. When there are a large number of recording powers included in the jitter allowable range, the recording power having the smallest jitter degree is determined as the optimal recording power.

On the other hand, in a rewritable disc such as a DVD-RW or a CD-RW, the higher the recording power is, the better the jitter characteristic is. Therefore, as shown in FIG. The recording power at the position with is determined as the optimum recording power Po. Here, the K value is determined by the experiment of the drive maker.

As described above, the present invention can increase the jitter degree by determining the recording power in which jitter is minimized under the same conditions as when the data is reproduced, or the portion in which the slope is sharply reduced based on the K value as the optimum recording power.

In addition, when OPC is performed in units of 1 ECC block, several sync frames (eg, the first 4 sync frames) of each physical sector perform high power recording in a recording pattern of 14T / 14T. When the first two sync frames are subjected to high power recording with a recording pattern of 14T / 14T, the PCA unused area can be easily and easily detected.

On the other hand, the present invention can be applied not only to DVD-R / RW but also to all discs that perform OPC.

As described above, according to the method of generating the optimum recording power according to the present invention, the optimum recording power is determined by using the jitter characteristic, so that the optimal recording power is achieved even in the DVD-R / RW having only the PCA area and the OPC method is not defined. Can be determined. In particular, by performing OPC in units of 1 sector, it is possible to increase the degree of OPC and overcome the limitation of the PCA region. That is, since the capacity of the PCA area is limited, it is possible to reduce the case where recording is not possible anymore because the OPC cannot be performed even though the recording space remains or can be recorded further.

In addition, by determining the recording power in accordance with the power calibration from the outer periphery or the inner periphery of the PCA area, seeking of the next power test area in the PCA becomes easy.

In addition, when OPC is performed on a DVD-R / RW by 1 sector unit, the start position of each physical sector can be found by the wobble synchronization method, so that the start position can be easily and accurately found in the odd sector. OPC can be performed accurately at the starting position.

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 (14)

Generating a recording pattern for performing optimal power control (OPC); Searching the area for performing the OPC and then recording the recording pattern while varying the recording power based on the reference recording power recorded on the optical recording medium in the searched area; Searching the area where the recording pattern is recorded to reproduce recorded data, and determining an optimum recording power from the jitter characteristic of the reproduction signal for each recording power; And And recording the user data inputted into the user data area on the optical recording medium which is determined by the determined optimal recording power. The method of claim 1, In this step, OPC is performed in units of ECC blocks, which are data recording and reproducing units, and the recording power is changed for each sector constituting the ECC block. The method of claim 2, wherein the recording pattern generated in the recording pattern generating step is A method of generating optimal recording power for an optical record carrier recording player, characterized in that it is a single recording pattern of random data or nT / nT. The method of claim 1, In this step, OPC is performed in units of sectors, and the recording power is changed for each N (N is a natural number) sync frame constituting a sector. The method of claim 4, wherein the recording pattern generated in the recording pattern generating step is An optimal recording power generation method for an optical record carrier recording player characterized in that it is a single recording pattern of nT / nT. The method of claim 4, wherein And if the OPC is performed in units of sectors, synchronizing sectors of the test area. 7. The method of claim 6, wherein the sector synchronization step is Detecting a signal wobbling on the signal track; Outputting a phase-locked wobble signal by applying a phase locked loop (PLL) to the wobbled signal; And counting the phase-locked wobble signal to detect the start position of each sector. 8. The method of claim 7, wherein said counting step A method of generating an optimum recording power of an optical record carrier recording player, characterized in that a count is reset at a start position of a first sector of an ECC block which is a data recording reproduction unit. The method of claim 1, wherein the determining of the optimal recording power Generating an RF signal by using an electric signal having an amount of light reflected at a position where a recording pattern is recorded for each recording power; Biasing the RF signal to a reference voltage after AC coupling; Detecting the jitter characteristic of the RF signal biased to a reference voltage after the AC coupling for each recording power; And determining the recording power within the jitter allowable range as an optimal recording power. 10. The method of claim 9, wherein determining the optimal recording power And if the optical recording medium is an optical recording medium that can be recorded once, determining the minimum recording power as the optimum recording power. 10. The method of claim 9, wherein determining the optimal recording power And if the optical recording medium is a rewritable optical recording medium, the recording power of the jitter having the highest jitter within the allowable range of jitter is determined as the optimal recording power. 12. The method of claim 11, wherein determining the optimal recording power If the optical recording medium is a rewritable optical recording medium, a value obtained by differentiating the jitter characteristic of each recording power ( A method for generating an optimal recording power of an optical record carrier recording player characterized in that the recording power at a position smaller than an experimental value K is determined as an optimal recording power. The method of claim 1, The OPC is performed in the circumferential direction from the inner circumference of the test area, and in this case, recording is performed from low power to high power. The method of claim 1, The OPC is performed from the outer circumference to the inner circumference of the test area, and in this case, recording is performed from high power to low power.