KR20010075741A - Method for writing data in an optical disk reader/writer - Google Patents

Abstract

PURPOSE: A recording method for a data in an optical recording player is provided to stably record the data through adjusting size of a servo error and an offset for a laser power used in recording the data. CONSTITUTION: An optical recording player decides kind of an inserted disk for adjusting a size of a servo error for a reproducing mode. Then, an AGC of a servo loop is performed to reduce effect from deviation in the servo error size adjustment. In case of the inserted disk as a recordable disk, a disk ID on a TOC area is read for reading a reflecting rate of the disk and servo error size ratio information from a data recording area. After calculating a change inclination of a servo error size for a laser eliminating power. By receiving a recording command, the player performs OPC for establishing an optimum laser recording/eliminating power. Then, a first servo error gain is established for establishing a servo error gain through adding or subtracting a servo error gain from the first servo error gain. Therefore, the received data is stably recorded on the disk.

Description

Method for writing data in an optical disk reader / writer

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical recorder, and in particular, in recording data on an optical disk, the data is stably adjusted by adjusting the magnitude and offset of the servo error with respect to the laser power used during data recording. A data recording method of an optical recorder capable of recording.

In general, optical recording media have a read only memory (ROM) type, a write once read many (WORM) type, and a rewritable rewritable type, depending on whether repeat recording is possible. It is classified into three types such as possible type.

Here, the ROM type optical recording medium includes a compact disc (CD) ROM and a digital versatile disc (DVD) ROM, and the WORM type optical recording medium is a write once compact disc (CD-R). Recodable Compact Discs and Recordable Digital Versatile Discs (DVD-R).

In addition, freely rewritable discs include a rewritable compact disc (CD-RW) and a rewritable digital versatile disc (DVD-RAM).

On the other hand, the optical recorder stores data on the disk by using a method of forming a pit by concentrating a high power laser on the recordable disk. However, in order to stably record data on the disc, servo control is required so that the laser beam focuses on the track and follows without leaving the track.

Here, this servo control is performed with reference to the servo error signal detected from the reflected light of the laser beam irradiated onto the disk. At this time, the magnitude of the detected servo error signal varies depending on the reflectance and state of the disk, the response characteristics of the light receiver, the intensity of the laser beam, and the like.

On the other hand, the optical recorder performs auto gain control (AGC) of the servo loop for stable servo control. 1 is a flowchart illustrating a process of performing an AGC of a servo loop on an inserted disc of a conventional optical recorder, and FIG. 2 is a diagram illustrating a board diagram of a servo loop on an inserted disc of a conventional optical recorder. .

Referring to FIG. 1, the automatic gain adjustment process of the servo loop of the optical recorder will be described. First, a disk is inserted (step 101), and the optical recorder is used to detect whether the inserted disk is a high-reflection CD-R / ROM. After determining whether it is a CD-RW (step 102), if there is a part that can adjust the size of the servo error, the size is set according to a preset value (step 103). Then all servos are turned on and AGC is performed (step 104).

On the other hand, when the magnitude of the servo error is large or small, such as 1 or 2, as shown in FIG. 2, crossover occurs and the phase margin is small, resulting in unstable servo. In this case, if AGC of the servo loop is performed, the servo is stabilized by moving the servo loop to the position of ③. By performing AGC of the servo loop in this way, the optical recording / reproducing apparatus is ready to stably reproduce the data of the inserted disc (step 105).

In addition, in order to stably record data on the disk, the average servo error during recording is measured for various types of disks and various laser erasing powers, and optical recording of the magnitude of the servo error to be compensated for during data recording is performed. The data recording servo is recorded in the player, and the data recording servo is performed in such a manner as to compensate the ACC result value of the servo loop performed at the beginning of disc recognition when entering the actual data recording or to reduce the magnitude of the servo error as necessary.

By the way, a disk used in an optical recorder may have various situations such as a disk in which no data is recorded, a disk in which data is recorded only in a partial region, and a disk in which data is recorded. As described above, the magnitude of the servo error generated in the disk in which the data is recorded and the unrecorded area are mixed is large.

Therefore, in the case of adjusting the magnitude of the recording servo error by the conventional method as described above, it is difficult to perform a stable operation corresponding to the magnitude of the servo error according to the disk and the laser erasing power, and to record data at the point where the AGC is performed. The difference in the magnitude of the servo error occurs depending on the state. In this case, there is a problem that the recording state becomes unstable because the servo error cannot be compensated properly.

The present invention has been made in view of the above problems, and in recording data on an optical disk, the data can be stably recorded by adjusting the magnitude and offset of the servo error with respect to the laser power used for data recording. It is an object of the present invention to provide a data recording method of an optical recorder.

1 is a flowchart illustrating a process of performing AGC of a servo loop on an inserted disc of a general optical recorder.

Fig. 2 shows a board diagram of a servo loop for an inserted disc of a typical optical recorder.

3 is a diagram conceptually illustrating the magnitude of a servo error according to a data recording / unrecorded area of a disc detected by a general optical recorder. FIG.

4 is a diagram showing a change in servo error magnitude with respect to laser erasing power of a disc detected in a general optical recorder.

5 is a flowchart showing an execution process of a data recording method of the optical recorder according to the present invention.

In order to achieve the above object, the data recording method of the optical recorder according to the present invention,

(a) performing AGC of a servo loop on the inserted disk;

(b) performing OPC according to the reception of the data write command, and setting the laser write / erase power from the result of performing the OPC;

(c) setting a primary servo error gain (Gs) from the set laser erase power (Ps) and the reflectance (Γ) of the inserted disc;

(d) setting a servo error gain (Gn) to be applied at the time of data recording by referring to the disk recording state of the area where the AGC of the servo loop is performed in step (a); And

(e) it is characterized in that it comprises the step of recording data by applying the set servo error gain (Gn).

Here, before step (a),

Investigating the reflectance (Γ) of each disk, the focus error size and tracking error size of the data recorded / unrecorded area of each disk, and storing the information of the disc according to the manufacturer;

Setting a reference disc from among discs of each type according to the manufacturer;

Measuring and storing a change rate (A) of a servo error magnitude with respect to laser erase power for the reference disc; And

And setting a reference laser erase power (Pr) for the reference disc, and for the reference laser erase power (Pr), a servo error gain (Gr) to be applied when data is written to the disc.

Further, in the step (c), the first servo error gain Gs is a servo to be applied at the time of data recording with respect to the reference laser erase power Pr for the reference disk and the reference laser erase power Pr. From the error gain Gr, the magnitude change rate A of the servo error with respect to the laser erase power of the reference disc, the laser erase power Ps set from the result of the OPC, and the reflectance of the inserted disc Γ

Gs = A × Γ × (Ps-Pr) + Gr

The characteristic is that the primary servo error gain Gs is set by using.

Further, the servo error gain Gn in step (d) is performed by the AGC of the servo loop in step (a) with reference to the difference between the servo error magnitudes of the area where data is recorded and the area where no data is recorded. If the recorded area is an area where no data is recorded, the difference between the servo error magnitudes is subtracted from the primary servo error gain Gs. If the area is recorded, the servo error is equal to the primary servo error gain Gs. The feature is that the servo error gain Gn to be applied at the time of data recording is set by adding the difference in magnitude.

According to the present invention, in recording data on an optical disk, the reflectance of each disk and the magnitude of the servo error in the data recording / unrecorded area of the disk by manufacturer's type are measured, and the servo error is referred to with reference to the measured data. By compensating for and setting the gain, there is an advantage that data can be recorded stably.

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

In order to perform the data recording method of the optical recorder according to the present invention, first, in order to reflect the characteristics of the discs of each type according to the manufacturer, the difference between the reflectance and the size of the servo error between the data recording / unrecorded area for each disc is composed of a table. do.

In this case, the disc can be classified by reading the manufacturer code recorded in the table of contents (TOC) area of the disc, and the difference between the reflectance and the servo error size can be obtained by actual measurement.

The contents of the table configured as described above are the ratio of the servo error size between the disc ID and the reflectance and the data recording / unrecording area. There are two types of servo errors, focus error and tracking error.

On the other hand, in order to construct a table, a reference disk is first selected from several disks, and the value measured from this disk is set to "1". Next, the values measured on each type of disc according to the manufacturer are composed of the values converted to the relative values with respect to the reference disc. One example configured as described above is shown in Table 1. Here, although the ratio of the magnitude of the focus error and the tracking error varies slightly depending on the modulation degree of the recording area, an average value is used.

Disk ID Reflectivity (Г) Servo error size ratio of data record / unrecorded area Focus error Tracking error One 1.0 1.0 1.0 2 0.9 0.8 0.9 3 1.1 1.2 1.5 ... ... ... ...

Since the magnitude of the servo error according to the laser erasing power increases linearly with respect to the laser erasing power intensity as shown by the dotted line of FIG. 4, the rate of change of the servo error magnitude with respect to the laser erasing power can be calculated by actual measurement. That is, the measurement of the slope A value is possible.

In addition, since the amount of light reflected by the laser light varies depending on the reflectance? Of the disk, this also affects the magnitude of the servo error. In this case, when the reflectance (G) is large, the reflected light is also large, and thus the magnitude of the servo error is influenced in the direction in which the servo error is increased.

Therefore, the magnitude of the servo error according to the laser erasing power and the reflectance? Can be represented by a linear equation having a slope A × Г. The dotted line in FIG. 4 is before the application of the reflectance (Г). When the reflectance (Г) is applied, the inclination is changed, so that it becomes like a straight line.

5 is a flowchart showing an execution process of a data recording method of the optical recorder according to the present invention.

Referring to Figure 5 will be described the execution process of the data recording method of the optical recorder according to the present invention. First, when a disc is inserted (step 501), the optical recording / reproducing apparatus judges whether the disc is a recordable disc by determining the type of the inserted disc and adjusts the size of the servo error appropriately at the time of reproduction (step 502). In addition, AGC of the servo loop is performed to reduce the influence of various factors such as the servo error scaling deviation on the adjusted servo error size (step 503).

Then, the optical recorder determines whether the inserted disc is a recordable disc (step 504). At this time, as a result of the determination in step 504, if the inserted disc is not a recordable disc, it is prepared for playback (step 505). If the inserted disc is a recordable disc, the manufacturer code (disc ID) recorded in the TOC area on the disc is recorded. (Step 506), it is determined whether or not there is information about the disc in the memory of the optical recorder (step 507).

At this time, as a result of the determination in step 507, if there is information on the disc inserted in the memory of the optical recorder, the reflectance of the disc and the servo error size ratio information in the data recording / unrecorded area are read (step 508). If there is no information on the disc inserted into the memory of the recorder, data (default value) set as a reference value is read (step 509).

On the other hand, the optical recorder calculates a change in slope A × Г of the servo error magnitude with respect to the laser erasing power with reference to the data read from the memory (step 510), and prepares to record the data (step 511).

When a recording command is received from the host (step 512), the optical recorder performs an OPC (step 513), and sets an optimal laser recording / erase power for the inserted disc from the result of the OPC (step 514). ).

Also, the optical recorder compensates for the AGC performance result in step 503 in order to perform stable servo upon data recording on the inserted disc. Referring to the compensation process, first, the optical recorder sets the first servo error gain Gs using the laser erase power set in step 514 (step 515).

Here, the primary servo error gain Gs is a reference laser erase power Pr for a reference disk set in advance, and a servo error gain Gr to be applied when data is written to the reference laser erase power Pr. ), The change rate (A) of the servo error magnitude with respect to the laser erase power of the reference disc, the laser erase power (Ps) set from the result of performing OPC in step 513, and the reflectance (Γ) of the inserted disc.

Gs = A × Γ × (Ps-Pr) + Gr

Is used to set the primary servo error gain (Gs).

The first servo error gain Gs set in step 515 is compensated according to whether the area in which the AGC of the servo loop is performed in step 503 is a data recorded / unrecorded area.

Referring to this compensation process, first, it is determined whether the area where the AGC of the servo loop is performed in step 503 is an unrecorded area (step 516). In this case, when the determination result in step 516 indicates that the area where the AGC of the servo loop is performed is the area where data is recorded, the servo error gain G1 is added to the primary servo error gain Gs (step 517). If the performed area is the area where no data is recorded, the servo error gain G2 is subtracted from the primary servo error gain Gs (step 518) to set the servo error gain Gn to be applied at the time of data recording (step 519). ).

Here, the difference of the servo error magnitude G1, G2, which is added or subtracted according to the data recording / unrecording of the area where the AGC of the servo loop is performed, is measured in advance and the servo error in the data recording / unrecorded area stored in the memory of the optical recorder. Can be obtained from size ratio information

Accordingly, the data received from the host is stably recorded on the inserted disc using the servo error gain set in step 519 (step 520).

As described above, in the data recording method of the optical recorder according to the present invention, in recording data on an optical disk, the reflectance of each disk and the size of servo error in the data recording / unrecorded area of the disk by manufacturer's type are measured. By compensating and setting the servo error gain with reference to the measured data, there is an advantage that data can be stably recorded.

Claims (4)

(a) performing AGC of a servo loop on the inserted disk; (b) performing OPC according to the reception of the data write command, and setting the laser write / erase power from the result of performing the OPC; (c) setting a primary servo error gain (Gs) from the set laser erase power (Ps) and the reflectance (Γ) of the inserted disc; (d) setting a servo error gain (Gn) to be applied at the time of data recording by referring to the disk recording state of the area where the AGC of the servo loop is performed in step (a); And and (e) recording the data by applying the set servo error gain (Gn). The method of claim 1, Before step (a) above, Investigating the reflectance (Γ) of each disk, the focus error size and tracking error size of the data recorded / unrecorded area of each disk, and storing the information of the disc according to the manufacturer; Setting a reference disc from among discs of each type according to the manufacturer; Measuring and storing a change rate (A) of a servo error magnitude with respect to laser erase power for the reference disc; And Setting a reference laser erase power (Pr) for the reference disc, and setting a servo error gain (Gr) to be applied when data is written to the disc with respect to the reference laser erase power (Pr). A data recording method of an optical recorder. The method of claim 1, The primary servo error gain Gs in the step (c) is Of the reference laser erase power Pr for the reference disc, the servo error gain Gr to be applied when data is recorded for the reference laser erase power Pr, and the magnitude of the servo error with respect to the laser erase power of the reference disc. From the change rate (A), the laser erase power (Ps) set from the result of the OPC and the reflectance (Γ) of the inserted disk Gs = A × Γ × (Ps-Pr) + Gr The first servo error gain (Gs) is set by using the data recording method of the optical recorder. The method of claim 1, The servo error gain Gn in the step (d) is The primary servo error gain is obtained when the area where the AGC of the servo loop in the step (a) is performed is referred to as a difference between the servo error magnitudes of the area where data is recorded and the area where no data is recorded. The difference between the servo error magnitudes is subtracted from (Gs), and if the area where data is recorded, the difference between the servo error magnitudes is added to the primary servo error gain (Gs), and the servo error gain (Gn) to be applied during data recording. Data recording method of an optical recording / reproducing device.