JPH05144004A - Optimum recording power detection method of write-once/ read-many-times type optical disk - Google Patents

Abstract

PURPOSE:To reduce detection errors due to scratchs and dusts on an optical disk and to reduce the possibilities of recording information with an incorrect power. CONSTITUTION:An N+1th area, which is a unit DRAW period with a test area 16, is divided into approximately equal areas (a) and (b). Based on the DRAW number information N detected by a first process, a test signal is recorded an N+1th area (a) within the test area 16 and reproduced. Furthermore, a second process which detects an optimum recording power Poa and a third process which records and reproduces test signals including this Poa in the region (b) and detects an optimum recording power Pob are provided. Therefore, the recording period of one level of the test signals in the third process is made longer (for example two frames). Moreover, when the Poa is not detected in the second process, the Pob is detected by recording and reproducing test signals of plural stage levels which are different than the second process, a detection error with an optimum recording power is eliminated.

Description

Detailed Description of the Invention

[0001]

The present invention relates to a CD (Compact).
In a write-once type optical disk recording apparatus capable of additional recording on the user side such as a Disk) -WO (Write Once) apparatus, the optimum power of laser light for recording data on an optical disk is detected. It is related to the improvement of the method.

[0002]

2. Description of the Related Art Conventionally, this kind of optimum recording power detection method has been performed as shown in FIGS. That is, (a) In the first step, first, the optical disc 10 shown in FIG.
From the read-in area 12 provided on the inner circumference side of the track in which the address information (for example, time information) is recorded, special information data (start time information T).
s and recommended recording power Pr) are read, and PCA (Power Calibrate) based on the start time information Ts in this special information data.
IonArea count area (Count A
rea) 14 is accessed.

In the count area 14, an area for recording information on the number of times of additional recording is set for each additional recording period (for example, one frame for one additional recording period (1 frame is (1 /
75) (representing seconds)) and set from the 1st to the 100th. By accessing the count area 14, the additional write count information is read to detect how many times the additional write has already been performed. For example, from the first to 1
EFM (Eight to Four) up to the Nth (for example, 50th) area out of the 00th area
Assuming that the een Modulation) signal is recorded, the number N of additional recordings (for example, 50 times) is detected.

(B) Next, in the second step, first, based on the information N on the number of additional recordings in the count area 14, the PCA
The test area (Test Area) 16 is accessed. In this test area 16, an area for recording a test signal in which the power level is switched in a plurality of steps (for example, 15 steps) is provided for each additional recording period (for example, the additional recording period is 15 frames). It is divided and set from 1st to 100th.

By accessing the test area 16, the power level is set to a predetermined power level (for example, the recommended power level Pr read from the read-in area 12).
A test signal (for example, an EFM signal) switched in a plurality of steps (for example, 15 steps) centered on is recorded in the (N + 1) th area corresponding to the additional recording number information N. That is,
If the additional write count information in the count area 14 is 50 times (that is, N = 50), 5 in the test area 16 is recorded.
15 frames of the first (ie N + 1 = 51) area
During the frame period, test signals having different power levels are recorded at a rate of one level and one frame.

(C) Then, a test signal having a different power level in a plurality of stages is reproduced from the N + 1th area (for example, the 51st area) in the test area 16 recorded in (B). Then, the optimum recording power Po is detected by the comparison output (asymmetry signal) of the reproduction signal and the reference signal.

(D) In the subsequent third step, the optimum recording power information detected in (c) above is recorded in the N + 1th area (for example, the 51st area) in the count area 14. For example, the EFM signal having the optimum recording power Po detected in the above (c) is recorded in the 51st area in the count area 14 as the optimum recording power information. As described above, the optimum recording power detection for the unit additional recording period is completed.

In FIG. 3, PMA () is an area for temporarily writing the read-in information relating to the data additionally written in the data area 18 of the optical disk 10, and PMA () after all the additional writing is completed. The read-in information therein is transferred to the original read-in area 12.

Reference numeral 20 is a clamp area provided on the innermost peripheral portion of the optical disk 10. 24, 26, 28
Are empty areas provided on the inner and outer peripheral sides of the test area 16 and on the outer peripheral side of the count area 14, respectively, and these empty areas 24, 26, and 28 are located in the test area 16 and the count area 14, respectively. In order to facilitate the search, a predetermined time (for example, 30 frames each) is set in advance. Reference numeral 30 is a read-out area provided on the outermost peripheral portion of the optical disc 10.

[0010]

However, the test signal to be recorded in a predetermined area (for example, N + 1th area) in the test area 16 in the second step has a predetermined period (for example, each frame of 15 frames). ), The signal is of a multi-step (for example, 15 steps) level centering on a predetermined recording power (for example, a recommended recording power Pr previously recorded in the read-in area 12), so that the optimum recording power Po
However, the recording time for one level is shortened (for example, one frame), and the optical disk 10
There is a problem that detection errors are likely to occur due to scratches and dust on the top.

Further, if the number of recording power steps is reduced (for example, 7 to 8 steps) and the recording time for one level is increased (for example, 2 frames), detection by scratches or dust on the optical disk 10 is detected. Although the number of mistakes is reduced, the recommended recording power Pr previously recorded in the read-in area 12 has a wavelength of 7
Since the laser light has a wavelength of 80 nm and is only a guide, there is a problem in that the optimum recording power Po cannot be found and recording may be performed with incorrect power. The present invention has been made in view of the above problems, and it is an optimum recording power of a write-once optical disc that can reduce detection error due to scratches and dust on the optical disc and reduce the risk of recording with wrong power. -It is intended to provide a detection method.

[0012]

An optimum recording power detection method for a write-once optical disc according to the present invention is a read-in area in which start time information is recorded in a track in which address information of the optical disc is recorded, and an additional recording. The count area, in which the area for recording the number of times information is divided and set for each additional recording period in units, and the area for recording the test signal in which the power level is switched in a plurality of stages are set in each additional recording period A test area is set which is divided into two equal parts, and the count area is accessed based on the start time information of the read-in area. Recording the test signal in one of two corresponding areas in the test area based on the first step of detection and the information detected in the first step. A second step of detecting the optimum recording power based on the comparison output of the reproduction signal and the reference signal, and a plurality of steps including the detection level when the optimum recording power can be detected in the second step. A third step of recording and reproducing a level test signal in the other of the two corresponding areas in the test area, and detecting the optimum recording power based on a comparison output of the reproduced signal and a reference signal; Second
When the optimum recording power cannot be detected in the process, a test signal of a plurality of levels different from the level of the test signal in the second process is recorded and reproduced in the other of the two corresponding areas in the test area. A fourth step of detecting an optimum recording power based on a comparison output of the reproduction signal and a reference signal
It is characterized by comprising a step and a fifth step of recording the optimum recording power information detected in the third or fourth step in a corresponding area of the count area.

[0013]

In the second step, even if the one-level recording period of the test signal to be recorded in one of the two corresponding areas in the test area is the same as the conventional one (for example, one frame),
When the optimum recording power can be detected in this second step,
In the third step, the one-level recording period of the test signal to be recorded in the other of the corresponding two areas in the test area can be made longer (for example, 2 frames) than before, so that a detection error due to scratches or dust on the optical disk may occur. Can be reduced.

Moreover, the optimum recording power is used in the second step.
Even if the signal is not detected, by setting the 1-level recording period of the test signal to be recorded in the other of the two corresponding areas in the test area in the fourth step to be the same as the conventional one (for example, 1 frame), Erroneous detection of the optimum recording power can be eliminated, and recording errors due to incorrect power can be reduced.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the optimum recording power detection method for a write-once optical disc according to the present invention will be described below with reference to FIGS. (A) In the first step, first, the optical disc 10 shown in FIG.
Special information data (start time information Ts and recommended recording power P) from the read-in area 12 of
(including r), and the start time information Ts (00: 00: 0) in this special information data is read.
The count area 14 in the PCA is accessed based on 0 (minute: second: frame)). For example, count area 1
The address information when accessing the first area in 4 is Ts-00: 13: 55.

By accessing the count area 14, the additional write count information is read to detect how many times the additional write has already been performed. For example, EF up to the Nth (for example, 50th) area of the 1st to 100th areas
Assuming that the M signal is recorded, the number N of additional recordings (for example, 50 times) is detected.

(B) Next, in the second step, first, based on the information N of the number of additional recordings in the count area 14, the PCA
One area a, which is obtained by dividing the (N + 1) th area in the test area 16 of FIG. By accessing the test area 16, the power level is a recommended recording power Pr of seven stages of test signals (for example, EFM).
Signal) is recorded in the area a in the (N + 1) th area of the test area 16 at a rate of one level and one frame.

(C) Next, a test signal having different power levels is reproduced from the area a in the N + 1th area (for example, the 51st area) in the test area 16 recorded in the above (b). It Then, the optimum recording power is obtained by comparing the reproduced signal with the reference signal.
Poa will be detected, but the optimum recording power Po
When a can be detected, proceed to the third step (d) below,
If the optimum recording power Poa cannot be detected, the process proceeds to the fourth step (e) described later.

(D) The optimum recording power in (c) above
In the third step, which is the next step when Poa is detected, a test signal (for example, EFM signal) having a small number of steps (for example, 4 steps) centered on the optimum recording power Poa detected in (c) above. However, N + of the test area 16 at a level of 1 level and 2 frames for 8 frames
It is recorded in the area b in the first area. Then, the test signal is reproduced from the area b in the (N + 1) th area. Then, the optimum recording power Pob is detected by the comparison output of the reproduction signal and the reference signal.

(E) Optimal recording power in (c) above
The next stage when Poa could not be detected is the fourth stage.
In the process, a plurality of stages (for example, 8 stages) of recording power test signals (for example E
FM signal) is recorded in the area b in the (N + 1) th area of the test area 16 at a rate of 1 level and 1 frame period for 8 frame periods. Then, the test signal is reproduced from the area b in the (N + 1) th area. Then, the optimum recording power Pob is detected by the comparison output of the reproduction signal and the reference signal.

The test signal when the optimum recording power Poa cannot be detected is selected as follows. That is, when the comparison outputs of the reproduction signal and the reference signal in (c) above are all at the L level, the level of the test signal at this time was too high. When the test signal of the recording power of the stage (for example, 8 stages) is selected and the comparison outputs of the reproduction signal and the reference signal in the above (c) are all at the H level,
Since the level of the test signal at this time is too low, a plurality of stages (for example, 8 stages) of recording power test signals on the higher level side than the (d) test signal are selected.

(F) Then, the EFM signal having the optimum recording power Pob detected in the third step (d) or the fourth step (e) is stored in the count area 14 as the optimum recording power information. Is recorded in the (N + 1) th area. As described above, the optimum recording power detection for the unit additional recording period is completed, and this is repeated thereafter.

In the above-mentioned embodiment, the test signal of the second step has seven levels of levels centered on the recommended recording power Pr in the read-in area, but the present invention is not limited to this, and the recommended recording power is not limited to this. Any signal having a plurality of levels of levels centering on the recording power other than -Pr may be used.

In the above-described embodiment, the test signal of the third step has four levels with the optimum recording power Poa detected in the second step as the four levels, and the recording period of one level is longer than that of the conventional one frame. Although it is set to be long (2 frames), the present invention is not limited to this, and may be of a plurality of stages (for example, 3 stages) in which one level recording period is made longer than in the past.

[0025]

As described above, when the optimum recording power can be detected in the second step, the detection level of the optimum recording power of the write-once optical disc according to the present invention is set to the third detection level.
Since the center of the test signal recorded in the test area in the process is the center of the test signal in the second process, the level of the test signal in the third process is the same as the conventional one (for example, one frame). The recording period can be made longer than before (for example, 2 frames), and detection errors due to scratches and dust on the optical disk can be reduced.

Moreover, the optimum recording power is used in the second step.
Even if could not be detected, the detection error of the optimum recording power is eliminated by making the 1-level recording period of the test signal recorded in the test area in the fourth step the same as the conventional one (for example, 1 frame). Therefore, it is possible to reduce recording errors due to incorrect power.

[Brief description of drawings]

FIG. 1 is a flow chart showing an embodiment of an optimum recording power detection method for a write-once optical disc according to the present invention.

FIG. 2 is an explanatory diagram of a write-once optical disc used for explaining the flow chart of FIG.

FIG. 3 is a flowchart showing an optimum recording power detection method for a write-once optical disc according to a conventional example.

FIG. 4 is an explanatory diagram of a write-once optical disc used in the description of the flowchart of FIG.

[Explanation of symbols]

10 ... Optical disc, 12 ... Read-in area, 14
… Count area, 16… test area, 18… data
Ta area, 20 ... Clamp area, 24, 26, 28
... vacant area, 30 ... read-out area, a ... one additional area (for example, N + 1th area) of the unit in the test area 16 is divided into two areas (areas), b ... within the test area 16 Unit additional recording period (for example, N + 1th area) The other area (area) obtained by dividing the area into two substantially equal parts, PCA ... Power Calibra
Optimal recording power, Pr. Recommended recording power, Ts ... Start time information.

Claims (2)

[Claims] 1. A read-in area, on which start time information is recorded, and an area for recording information on the number of times of additional recording, are divided for each additional recording period on a track on which address information of an optical disk is recorded. With the set count area,
A test area in which an area for recording a test signal in which the power level is switched to a plurality of steps is set to be divided into approximately equal parts for each additional recording period is provided, and the start time information of the read-in area is provided. Based on the information detected in the first step, the first step of accessing the count area based on the information and detecting how many times the additional recording has already been performed, and the correspondence in the test area The second step of recording and reproducing the test signal in one of the two areas to detect the optimum recording power based on the comparison output of the reproduction signal and the reference signal, and the optimum recording power in the second step. When − is detected, a test signal of a plurality of levels including the detection level is recorded and reproduced in the other of the two corresponding areas in the test area, and the reproduction signal and the reference signal The optimum recording power on the basis of 較出 force -
Optimum recording power in the third step of detecting
, The test signal of a plurality of levels different from the level of the test signal in the second step is recorded and reproduced in the other of the two corresponding areas in the test area, and the reproduced signal and the reference are reproduced. A fourth step of detecting the optimum recording power based on a comparison output with a signal, and a fifth step of recording the optimum recording power information detected in the third or fourth step in a corresponding area of the count area. Optimal recording power detection method for write-once optical discs. 2. A recommended recording power pre-recorded in a read-in area for a test signal recorded and reproduced in one of two corresponding areas in the test area in the second step.
2. A signal of a multi-step level centered on
Optimal recording power detection method for the write-once optical disc described.