JPS63155424A - Information rewriting method for optical disk - Google Patents

Abstract

PURPOSE:To simply and with high accuracy rewrite the information of an optical disk by using a clock signal of a disk in which information is recorded in advance, and reading the information recorded in the disk immediately before recording at the time of rewriting the information. CONSTITUTION:With respect to an optical disk in which an information signal containing a clock is recorded in advance, of all, signal is reproduced by a light beam for read-out, and a fundamental clock signal is taken out therefrom. Subsequently, this fundamental clock signal is compared with a reference clock signal, and if a shift exists between the clock signal, the revolving speed of a motor is controlled so as to correct the shift. When a signal recorded in advance is that which is recorded at a prescribed peripheral velocity, information is rewritten at the same prescribed peripheral velocity by this control. Accordingly, the peripheral velocity of the optical disk of recording the information can be controlled by a simple device.

Description

[Detailed description of the invention] Serum! The present invention solves the problem in the field of optical discs, where conventional methods for controlling the speed of medium movement are extremely complicated, especially when recording or rewriting information.
By controlling the medium movement speed based on already recorded information, the medium movement speed can be easily and accurately controlled, and the information on the optical disc can be rewritten.

INDUSTRIAL APPLICATION FIELD The present invention relates to a method for recording information on an optical disc, and more particularly to a method for controlling the moving speed of a medium when rewriting information on an optical disc.

Conventional Technology In recent years, with the development of optical technology, optical discs have become known that record information on a substrate surface using a light beam such as a laser diode, and then read the information by detecting this recorded information with the light beam. .

Such optical discs are broadly divided into non-rewritable playback-only discs, write-once discs on which information can be written only once, and rewritable erasable discs.In recent years, rewritable optical discs have attracted particular attention. ing. When writing information on this rewritable optical disk, generally a high-intensity laser light pulse of 1 μm is used.
Although the medium surface is irradiated with the following diameter, since the medium is moving, it has conventionally been extremely difficult to control the intensity and irradiation time to optimal values.

That is, according to the conventional method, in order to change the intensity and irradiation time according to changes in the medium movement speed, the optimum conditions are measured in advance, and the medium movement speed at that point is always measured. It was necessary to derive the optimal conditions for irradiating the light beam. On the other hand, if the medium/travel speed is always kept at -1, the light beam irradiation conditions can be fixed at a predetermined optimum value, but in this case, if the recording radius position of the medium changes, , it was necessary to change the rotation speed accordingly. Therefore,
Conventionally, the radial position of the optical disc to be recorded is measured, and based on the measurement results, the rotation speed of the disc is calculated so that the medium movement speed reaches a predetermined value, and the disc drive motor is controlled to match that. A method was taken to do so.

Problems to be Solved by the Invention As mentioned above, in the conventional example, a position detector and an arithmetic circuit are required for information rewriting control, which has the drawback of making the device large-scale and at the same time increasing cost. Therefore, the present invention aims to improve the conventional method and rewrite information on an optical disc more easily and with higher precision.

Means for Solving the Problem The problem with the prior art described above is that when rewriting information on an optical disk, an information clock is extracted from the signal at the same time as the already recorded signal is reproduced by a readout beam, and then this information clock is This problem can be solved by an information rewriting method for an optical disk in which new information is recorded using a subsequent rewriting beam or erasing and recording beam while controlling the medium moving speed to maintain a constant frequency of .

That is, according to the present invention, as shown in the principle diagrams in FIGS. 1 and 2, signals are first reproduced with a reading light beam on an optical disk on which information signals including a clock are recorded in advance, The basic clock signal is extracted from it. Next, this basic clock signal is compared with a reference clock signal, and the rotation speed of the motor is controlled to correct any deviation between the clock signals. The pre-recorded signal
If the information was recorded at a constant circumferential speed, this control allows the information to be rewritten at the same constant circumferential speed. In this manner, in the rewriting method according to the present invention, information is recorded using the recording beam while performing the above-described control.

In the present invention, a clock signal from a disc on which information is recorded in advance is used, and when rewriting information, by reading the information recorded on the disc immediately before recording, the circumferential speed of the portion of the medium to be recorded can be determined. It can be read as is, and there is no need to use a complicated device that measures the radial position with the rotational speed and multiplies it to determine the circumferential speed as in the prior art.

Takumi Tomoshiki The present invention will be described in detail below, but it goes without saying that the technical scope of the present invention is not limited to these Examples.

Example 1 A spiral group groove with a pitch of 1.6 μm was provided, and the inner diameter was 15 mm and the outer diameter was 5e-1n-sb alloy film with a thickness of 90 nm formed by ternary vacuum evaporation and a ZnS protective film thereon. A glass transparent substrate coated with an ultraviolet curing resin with a diameter of 120 mm and a thickness of 1.2 mm was coated with a constant circumferential speed (1
,4m/S) and E F M (Eight to Fo
A compact disc (CD) format signal was recorded.

This disk was inserted into a recording apparatus employing the method of the present invention and equipped with an optical head in which three laser beams, a reading beam, an erasing beam, and a recording beam, were installed in a straight line. Signals were reproduced from this disk using vertical focus servo and left and right tracking servo, and a basic clock was extracted from this signal. This basic clock signal is compared with a reference frequency of 4.321 MFlz (built-in oscillator) and PLL (Phase Locked Loop
) circuit controlled the speed of the disk rotation morph, and closed-loop control was performed so that the reproduction clock was 4.3218 MHz. This increases the circumferential speed to 1.4 m/s
was gotten. On the other hand, old information was erased using an erasing beam following the reproducing beam, and new information was immediately recorded using a recording beam.

In this way, 1.
Recording can be performed at a circumferential speed of 4 m/s, and since the circumferential speed is fixed, erasing beam conditions (1 x 4 μm, 10 mW) and recording beam conditions (
0.9 mφ, 5 mW), there was no need to change the laser power and it could be kept constant.

Example 2 New information was overwritten on the old information in the same manner as in Example 1 except that an optical head equipped with two laser beams, a reproduction beam and a rewriting beam, was used. It was possible to rewrite in exactly the same way as in Example 1.

〔Effect of the invention〕

As explained above, according to the present invention, the peripheral speed of the optical disk on which information is to be recorded can be controlled by a simple device, and the intensity irradiation time of the recording beam can thereby be fixed at an optimal constant value. Therefore, the effect of stable recording can be obtained.

[Brief explanation of the drawing]

1 and 2 are diagrams showing the principle of the method for rewriting information on an optical disc according to the present invention.

Claims (1)

[Claims] 1. When rewriting information on an optical disk, the read beam reproduces the already recorded signal and at the same time extracts an information clock from it, and then controls the medium movement speed so that this information clock has a predetermined constant frequency. A method for rewriting information on an optical disc in which new information is recorded using a subsequent rewriting beam or erasing and recording beam.