JPH03173931A - Optical disk recorder - Google Patents

Abstract

PURPOSE:To realize recording under revolving speed other than a rating by providing a calculating means for converting optimum recording laser power under the rated revolution into optimum recording laser power under other revolution. CONSTITUTION:The optimum recording laser power PV at a medium linear velocity V is given by an expression I. The laser power PV is calculated by a calculation circuit 7 based on laser power PVO at a rated revolution of velocity VO. This PV is transmitted to a laser driving circuit 8, and a laser of a recording head 2 is driven by the circuit 8 in accordance with inputted information from a signal generator 9, so that the recording is performed. Thus, when an ISO standard optical disk is to be recorded under a nonrated revolving speed, since the optimum recording laser power in an optional radial position at a desired revolving speed can be obtained, the laser power is controlled according to this value and hence an optical disk is recorded by the optimum recording laser.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an optical disc recording device that uses light to write signals on a disc-shaped recording medium that rotates at a constant angular velocity.

The above-mentioned disk-shaped recording media include various types of optical disks, such as optical disks in which signals are written using concavo-convex pits, and magneto-optical disks in which signals are written in a perpendicularly magnetized film according to the direction of magnetization.

[Conventional technology]

There are various types of optical disk devices that record signals by irradiating a rotating disk-shaped medium with a laser beam and moving the medium and the laser beam irradiation stop relatively, and there are various types of disk media. . The optimum laser power for recording is set depending on the method and type of medium.

Furthermore, when an optical disc is rotated at a constant angular velocity, the linear velocity differs between the outermost track and the innermost track of the disc.

Generally, the optimum laser power for irradiating an optical disk during recording depends on the relative moving speed between the medium and the light beam, that is, the linear velocity at which the light beam spot traces the track.

For example, in order to always irradiate constant laser energy per unit track length and unit area on an optical disk that is rotationally driven at a constant angular velocity, it is necessary to increase the laser output toward the outer periphery.

Therefore, the ISO standard stipulates that the optimum recording laser power at the outermost and innermost tracks of an optical disk that is rotationally driven at a certain angular velocity (rated rotational speed) is to be recorded as data on the optical disk. (This optical disc is hereinafter referred to as an ISO standard optical disc.) Therefore, ISO
When recording on a standard optical disc for the first time, it is possible to determine the optimal value of the recording laser power by reproducing the data on the optical disc before recording, which is convenient because there is no need to determine the optimal recording laser power by trial and error. . (This optical disc is hereinafter referred to as an ISO standard optical disc.) Conventional optical disc recording devices read the optimal recording laser power data on the innermost and outermost tracks,
The optimum recording laser power at any radial position on the disk is calculated by linear interpolation, and the recording laser power is controlled accordingly.

[Problem to be solved by the invention]

However, in the prior art as described above, the optimum recording laser power data for the ISO standard optical disc is recorded only as determined under the rated rotation speed, so the optimum recording laser power at the normal rotation speed is not known.

Here, the optical disc does not necessarily have to be used at the rated rotation speed; for example, an optical disc manufactured by an optical disc manufacturer assuming a rotation speed of 180 Orpm may be used by a user at 360 Orpm without any problem. That is, the number of rotations is essentially completely unrelated.

However, as mentioned above, the optimum recording laser power data for an ISO standard optical disk is at the rated rotation speed, so when using the disk at a rotation speed other than that, the value of the optimum recording laser power cannot be used as is.

Since the optimal recording laser power at 3600 rpm cannot be determined from the recorded data, conventionally the user has had to find it anew through trial and error, which is extremely troublesome.

The present invention was made in view of these conventional problems.
To obtain an optical disc recording device capable of immediately determining the optimum recording laser power for an ISO standard optical disc when recording the optimum recording laser power on the optical disc at a rotation speed other than the rated rotation speed.

[Means to solve problems]

In order to solve the above problems, the present invention includes a calculation means for converting the optimum recording laser power found at the rated rotation n1 into the optimum recording laser power at another rotation n2.

That is, in an optical disk recording device using an optical disk in which optimum recording laser power at at least two different radial positions when being rotated at a constant angular velocity is written as data, the optimum recording laser power at at least two different radial positions is written as data, and based on the data, the optimum recording laser power is recorded at a speed other than the constant angular velocity. The apparatus includes a calculation means for calculating the optimum recording laser power when rotationally driven at an angular velocity of , and a laser power control means for controlling the output of the recording laser power based on the output of the calculation means.

[Effect]

As a result of research, the inventor has confirmed that the relationship between the medium linear velocity V and the optimum recording laser power Pv is given by P v = c v ''-1 (1).

Optimum recording laser power P for the innermost track and outermost track at the rated rotation speed for an Is○ standard optical disc
v and Pv are obtained by reproducing the data.

Further, the linear velocities V and Vo of the innermost track and the outermost track at the rated rotation are calculated.

■ 2πrR Radial position revolutions per second Therefore, from equation (1), a and C can be obtained as follows.

a and C are values determined by the structure and material of the disk.

this (2) and (3) Expression a and C are (1) In equation Substitute P as in the formula below.

You can ask for

V, 1 Therefore, based on the data of the optimum laser power at the rated rotation, the optimum laser power Pv at an arbitrary linear velocity V (that is, at an arbitrary radial position of a disk rotating at an arbitrary constant angular velocity) can be calculated.

Therefore, if it is an ISO standard optical disc, the optimum laser power can be determined at any rotation speed and at any radial position.

〔Example〕

The figure is a block diagram showing the configuration of an embodiment of the present invention.

l is an ISO standard rewritable 130mm magneto-optical disk,
2 is a recording head, 3 is a reproducing head, 4 is a spindle motor that rotates the disk, 5 is a slider that controls the position of the optical head 2.3, 6 is a decoder that decodes the signal from the reproducing head 3, and 7 is a decoder that decodes the signal from the reproducing head 3. Arithmetic circuit, 8 is recording head 2
9 is a signal generator that generates a modulation pattern.

In the figure, a disk 1 is moved by a spindle motor 4.
Rotate at a constant angular velocity of 3600 rpm.

Then, the reproducing head 3 is accessed by the slider 5 to the SFP zone (area where the optimum recording power data is recorded) of the disk 1, and information about the optimum recording power at the 30 mm and 60 mm radius positions is reproduced, and the information is decoded by the decoder 6. It is read out that the optimum recording power for the pulse width T of the laser drive pulse of 1800 rpm, which is the ISO standard, is 5.0 mW at a radius of 30 mm and 7.8 mW at a radius of 60 mm, and inputted into the calculation means 7. In order to obtain the recording power at an arbitrary position when the disk 1 is rotated by the spindle motor 4 at 3600 rpm, a and C are obtained by the calculating means 7 as follows.

Therefore, Pv=1.64XV'·12.

If this is expressed as an arbitrary radial position r (mm) at 3600 rpm, it becomes P=O1877x r '' 2 [mW].

Next, the recording head 2 was moved to a position with a radius of 50 mm by the slider 5, and information on that position was manually entered into the calculation means 7. Arithmetic means 7 substitutes 50 for r, P=0.877x5
0°"" = 10.8 [mW].

This value of P is transmitted to the laser drive circuit 8, and the laser drive circuit 8 drives the laser of the recording head 2 according to the information input from the signal generator 9, and the radius of the disk 1 is 50 m.
Record at position m.

〔Effect of the invention〕

According to the present invention, when an optical disc recording device attempts to record on an ISO standard optical disc at a rotation speed other than the rated rotation speed, it is possible to immediately determine the optimum recording laser power at any radial position at the desired rotation speed. Therefore, it is possible to control the laser power and record on the optical disc with the optimum recording laser power.

[Brief explanation of the drawing]

The figure is a block diagram showing an embodiment of the present invention. [Explanation of symbols of main parts] ■--------・-1----Magneto-optical disk 2...
・−−−−−−−m−−・−・−Recording head 3−・−−
−1−・・−・−・・−Playback head 4−−−・・・・・
−・−・−・Spindle motor 5−−・・−・−・−Slider 6 for head position control・−−−−−−−1°−°°
゛Decoder 7 - - - - - - - - - - - Arithmetic circuit 8
−−−・・−・−Laser drive circuit 9−・−・・−
...-signal generator

Claims (2)

[Claims] (1) In an optical disc recording device using an optical disc in which optimal recording laser power at at least two different radial positions when being rotated at a constant angular velocity is written as data, the constant angular velocity is determined based on the data. An optical disc recording comprising: a calculation means for calculating the optimum recording laser power when rotationally driven at an angular velocity other than Device. (2) The optical disc recording device according to claim 1, wherein the calculation means performs calculation according to the following equation. Pv=cv^■ Here a=(log[Pv_i/Pv__0])/(log[
v_i/v_0]) c=Pv_0/v_0^■ However, n_1: Rated rotation speed v_0: Linear speed v_i at radius r_0 at rated rotation
:Linear velocity Pv_0 at radius r_1 during rated rotation: Optimum recording laser power Pv_i at radius r_0 during rated rotation: Optimum recording laser power at radius r_1 during rated rotation v_0=2πr_0n_1 v_i=2πr_1n_1 v: Arbitrary linear velocity Pv: Optimal recording laser power calculated at arbitrary linear velocity v