JPH05120684A - Method for recording optical disk - Google Patents

Abstract

PURPOSE:To perform the light modulation overwriting with a low error ratio at the recording and reproduction by making the laser deletion power to be applied in the case of a short recording pit interval shorter than that in case of a long recording pit interval. CONSTITUTION:An optical disk capable of light modulation overwriting is irradiated with the higher laser power in the case of forming a recording pit and with the lower laser power than the recording time in the case of deletion. In short, the recording pit is recorded at the temperature higher than T1, and deleted within the temperature range from lower than T1 and up to T2. When a recording bit is short, the location which is originally under the T2 is fluctuated by the thermal interference between recording bits, increasing an error ratio. This tendency is remarkable in the optical disk capable of light modulation overwriting since the optical disk is irradiated with laser for deletion during recordings. An error ratio is reduced if the laser power at the deletion is controlled so as to prevent the excess temperature rise of the deletion section of a recording film.

Description

Detailed Description of the Invention

[0001]

The present invention relates to an optical disc recording method,
In particular, it relates to a recording method for an optical modulation overwrite type optical disc.

[0002]

2. Description of the Related Art Optical discs have already been commercialized as large-capacity, randomly accessible, removable media files. However, higher recording density is desired for use in digital image files and the like.

In order to increase the recording density of optical disks, studies have been made on shortening the recording / reproducing wavelength, improving the optical system, improving the efficiency of the modulation code, and the width recording method. further,
In order to shorten the access time, development is underway to put the overwrite function into practical use.

Further, there is known a method of performing recording compensation by controlling the laser power at the time of recording in order to prevent the recording pits from becoming tear-shaped when recording by the width recording method.

[0005]

The optical modulation overwrite type optical disk has a drawback that the error rate becomes large if the recording pit interval is shortened in order to increase the recording density. Further, this drawback becomes more remarkable when the width recording method is used together.

An object of the present invention is to provide a recording method for an optical modulation overwrite optical disk having a sufficiently low error rate during recording and reproduction.

[0007]

According to the present invention, in a method for recording an optical modulation overwrite type optical disc, a laser erasing power applied when a recording pit interval is short is set to be lower than when a recording pit interval is long. Is characterized by.

According to the present invention, it is possible to realize a recording method of an optical disk which has a low error rate at the time of recording / reproducing and also has a low error rate when the width recording method is used together.

[0009]

[Function] In the optical modulation overwritable optical disk,
When forming a recording pit, a high laser power is applied, and when erasing, a laser power lower than that for recording is applied. That is, it is recorded at a certain temperature T1 or higher and is erased in a certain temperature range up to a certain temperature T2 which is lower than T1. When the recording pit interval is short, due to thermal interference between the recording pits,
The position where the temperature is originally below T2 fluctuates, and as a result, the error rate increases. This tendency is remarkable in the optical modulation overwritable optical disk because the laser is irradiated for erasing between recordings. The error rate is reduced by controlling the laser power during erasure so that the temperature of the erasure portion of the recording film is not raised more than necessary.

[0010]

EXAMPLES The present invention will be described based on examples. The magneto-optical disk whose recording / reproducing characteristics were measured was a SiN dielectric base film with a film thickness of 80 nm and a film thickness of 30 n on a polycarbonate substrate.
m TbFeCo film, 5 nm thick GdNdFeCo film
Film, GdTbFeCo film with a film thickness of 50 nm and film thickness 80
nm SiN dielectric protective film. This disk was recorded at a linear velocity of 11.3 (m / s) and a recording magnetic field of 300 (O
e), under the condition of the preceding auxiliary magnetic field 4 (KOe), a random pattern was recorded with NRZI, and the error rate was measured with a reproduction power of 1 mW.

FIG. 2 is a diagram showing the relationship between the conventional laser power and the recording pattern, and FIG. 1 is a diagram showing the relationship between the laser power and the recording pattern in the present invention. 1 and 2, reference numeral 1 denotes a recording pit.

In FIG. 2, the recording power 2 is 12 mW,
The erasing power 3 is 6 mW, and these power settings are not changed regardless of the recording bit interval.

On the other hand, in FIG. 1, only the erasing power 4 is controlled to 4 mW when the recording pit interval is the shortest, that is, when the pit interval is 0.68 μm. The error rate was 10 ⁻³ in the past, but it was 10 ⁻⁴ by using the method of the present invention, which was an improvement of one digit.

[0014]

As described above, according to the present invention, the laser erasing power applied when the recording pit interval is short is set lower than that when the recording pit interval is long.
An optical disc recording method having an error rate sufficiently low for recording and reproduction was obtained.

[Brief description of drawings]

FIG. 1 is a diagram showing a relationship between a conventional laser power and a recording pattern.

FIG. 2 is a diagram showing a relationship between a laser power and a recording pattern in the present invention.

[Explanation of symbols]

 1 recording pit 2 recording power level 3 conventional erasing power level 4 erasing power level when recording pit interval is shortest

Claims (1)

[Claims] 1. A method for recording an optical disk of the optical modulation overwrite system, wherein the laser erasing power applied when the recording pit interval is short is set lower than when the recording pit interval is long. ..