KR20040090110A - Method for generating optimized record power in optical record/player - Google Patents

Abstract

PURPOSE: A method for generating an optimum recording power in an optical recording/reproducing system is provided to determine an obtained recording power as an optimum recording power, and to perform a substantial data recording process with the determined recording power. CONSTITUTION: A system changes a recording power based on a reference recording power recorded on an optical recording medium, tests/records a 14T mark-space and a 3T mark-space in an unrecorded test area of a PCA(Power Calibration Area) of the optical recording medium, and tests/records a 14T mark-space and a 4T mark-space(201,202). The system reproduces data recorded in a test area while changing the recording power, and obtains an asymmetry value for the 14T and the 3T and an asymmetry value for the 14T and the 4T in each recording power step(203). The system determines a recording power in which a difference between the asymmetry values is nearest to 0 as an optimum recording power(204). The system records user data inputted in a user data area of the optical recording medium with the determined optimum recording power(205).

Description

Method for generating optimized record power in optical record reproduction system {Method for generating optimized record power in optical record / player}

TECHNICAL FIELD 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 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 circumference.

FIG. 1A is a layout diagram of a recording area of a general CD-R / RW, which is 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 stages based on the reference power recommended by the disc manufacturer to test the test 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, the assumption is made that the appropriate recording power is assumed, and then the recordable user area 28 is determined with the determined recording power. Record the data in. The reference power is encoded in special information of the ATIP in the lead-in area.

On the other hand, even in the case of recordable DVD-based optical discs, for example, DVD-R / RW, the PCA area has a PCA like 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.

An object of the present invention is to record the nT EFM signal in the test area before starting data recording, and then calculate the asymmetry value of the DC Hi-Fi (HF) signal for each recording power and use it to optimize the recordable DVD. There is provided a method for generating a recording power.

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 flowchart for performing an optimal recording power generation method in the optical recording and reproducing system according to the present invention.

3 is a waveform diagram that defines the asymmetry characteristic detected from a reproduced HF signal for generating optimal recording power in accordance with the present invention.

Explanation of symbols for main parts of the drawings

10: clamping area 20: recording area

22: power adjustment area (PCA) 24: program memory area (PMA)

26: lead-in area 28: user data area

30: lead-out area

In the optical recording and reproducing system according to the present invention for achieving the above object, the recording power is changed in N steps based on the reference recording power recorded on an optical recording medium such as a recordable DVD. And performing test recording of 14T mark-space and 3T mark-space in the unrecorded test area of the PCA of the optical recording medium, followed by test recording of 14T mark-space and 4T mark-space. Reproducing the data recorded in the test area while changing the recording power in N steps, and obtaining the symmetry values for 14T and 3T and the symmetry values for 14T and 4T for each recording power step from the reproduction signal; The difference between the symmetry value for 3T and the symmetry value for 14T and 4T determines the recording power of the stage closest to zero as the optimal recording power. Characterized by comprising the step of recording the user data input to the tap and the user data area on the optical recording medium, the given group by the determined optimum recording power.

The reproduction signal of the step is a DC coupled hi-fi (HF) signal.

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, with reference to the accompanying drawings illustrating the configuration and operation of the embodiment of the present invention, the configuration and operation of the present invention shown in the drawings and described by it will be described as at least one embodiment, By the technical spirit of the present invention described above and its core configuration and operation is not limited.

Fig. 2 is a flowchart for performing an optimal recording power generation method in the optical recording and reproducing system according to the present invention. When a recording command for recording user data on a recordable DVD is input (step 201), the optical disk recording and reproducing apparatus is executed. Read the ATIP information recorded on the disc and divide the recording power into N steps (e.g. 15 steps) around the reference power recommended by the disc manufacturer. Then, the test space of the 14T mark-space and the 3T mark-space are recorded in the test area of the PCA 22 at the corresponding recording power, and then the 14T mark-space and the 4T mark-space are recorded. (Step 202). When the test recording is completed for each step, the data of each step recorded in the test area in step 202 is reproduced to detect the optimum recording power. And, from the DC coupled HF signal reproduced as shown in FIG. Asymmetry (4) is obtained (step 203).

3 is an HF signal reproduced after test recording of 3T (or 4T) mark-space after 14T mark-space test recording in the test area, which is always greater than zero. That is, since the reference value is not a zero point but a DC value, the signal as shown in FIG. 3 is called a DC coupled HF signal.

In Fig. 3, A1 and A2 are positive and negative peak values of the reproduction HF signal for 14T mark-space recording signal, and A1 'and A2' are reproduction HF for 3T (or 4T) mark-space recording signal. The positive and negative peak values of the signal.

In this case, Asymmetry (3), which is an asymmetry value for 14T and 3T, and Asymmetry (4), which is an asymmetry value for 14T and 4T, may be obtained as in Equation 1 below.

That is, after applying Equation 1 above to obtain Asymmetry (3), which is an asymmetry value for 14T and 3T, and Asymmetry (4), which is an asymmetry value for 14T and 4T, for each step, Asymmetry (3) among the N steps. The recording power at the stage where Asymmetry 4 and Asymmetry are equal is determined as the optimum recording power (step 204). That is, by comparing the sizes of Asymmetry (3) and Asymmetry (4) in each step, the recording power of the step closest to Asymmetry (3)-Asymmetry (4) = 0 is determined as the optimal recording power. For example, assuming that the recording power is divided into 15 levels based on the reference power when performing OPC, and in the third step, Asymmetry (3) = Asymmetry (4), Is determined as the optimal recording power. Then, actual user data is recorded in the recordable user data area 28 at the determined recording power (step 205).

As described above, according to the method of generating an optimal recording power in the optical recording and reproducing system according to the present invention, the OPC process is performed before recording data in the DVD recording and reproducing system. Divide into N steps, test record 14T mark-space and 3T mark-space at the corresponding recording power in each step in the test area of PCA, then test record the 14T mark-space and 4T mark-space and play them back. After obtaining Asymmetry (3) and Asymmetry (4) from the DC coupled HF signal, the recording power of the step where Asymmetry (3) = Asymmetry (4) is determined as the optimal recording power and actual data is recorded with the determined recording power. By performing the above, it is possible to generate more accurate optimal recording power on a recordable DVD related disc. That is, since the asymmetry parameters Asymmetry 3 and Asymmetry 4 of the present invention are obtained using both peak-to-peak of 14T and 3T and peak-to-peak information of 14T and 4T, more accurate optimum recording power can be obtained.

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 (4)

A method of generating optimum recording power in an optical recording / reproducing system that performs an optimum power control (OPC) when a recording command for recording data is input to a recordable optical recording medium, (a) 14T mark-space and 3T mark in the unrecorded test area of the power adjustment area PCA of the optical recording medium while changing the recording power in N steps around the reference recording power recorded on the optical recording medium. Test recording the space, followed by test recording the 14T mark-space and the 4T mark-space; (b) Reproducing the data recorded in the test area while changing the recording power to step N in the step (a), and the symmetric values for 14T and 3T and the symmetric values for 14T and 4T are respectively recorded from the reproduction signal. Obtaining step by step; (c) determining the recording power of the stage where the difference between the symmetry values for 14T and 3T and the symmetry values for 14T and 4T is closest to zero as an optimum recording power; And and (d) recording the user data inputted into the user data area on the optical recording medium which has been determined at the determined optimal recording power. The reproduction signal of claim 1, wherein A method of generating optimal recording power in an optical recording / reproducing system, characterized in that it is a DC coupled hi-fi (HF) signal. The method of claim 1, In step (b), the symmetry value Asymmetry (3) for 14T and 3T is obtained by applying the following equation. Here, A1 and A2 are positive and negative peak values of the reproduction HF signal for the 14T mark-space recording signal, and A1 'and A2' are the positive peak and negative peak of the reproduction HF signal for the 3T mark-space recording signal. Value. The method of claim 1, In step (b), the symmetry value Asymmetry (4) for 14T and 4T is obtained by applying the following equation. Here, A1 and A2 are the positive peak and negative peak values of the reproduction HF signal for the 14T mark-space recording signal, and A1 'and A2' are the positive peak and negative peak of the reproduction HF signal for the 4T mark-space recording signal. Value.