JPS6013334A - Optical recording and reproducing device - Google Patents

Abstract

PURPOSE:To record a signal with each proper recording beam power for every disc to be used to obtain a proper reproduced signal by finding out a beam power value maximizing reference wave reproducing voltage and minimizing secondary higher harmonics distortion reproducing voltage and using the beam power value as proper recording beam power. CONSTITUTION:The operation is set to a recording mode and laser light rays having different beam power values are successively irradiated from a power variable laser generator 15 and recorded at different positions on a disc 6 respectively while increasing the beam power value gradually until the value reaches a prescribed value. Subsequently, the operation is switched to a reproducing mode and reproduced laser light obtained from the disc 6 is converted into signal current corresponding to the size of a pit by an information signal reproducer 16. Reference wave voltage e1 and secondary higher harmonics distortion voltage e2 are extracted from band filters 181, 182 respectively through an amplifier 17 and A/D-converted and the digital values are supplied to a memory and an operator 22. Then, the beam power value minimizing the voltage e2 during the period that the voltage e1 is maximum is found out. The beam power value is converted into an analog value by a D/A converter 23 and the analog value is supplied to the power-variable laser generator 15. Thus, data can be recorded with the optimum recording beam power to the disc to be used.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is an optical recording and reproducing apparatus that is capable of recording with an appropriate recording beam power depending on the recording medium used and obtaining a reproduction signal of an appropriate level. The purpose is to provide

FIG. 1 shows a schematic diagram of an example of a general photothermal magnetic recording and reproducing apparatus. After the 1-noise light from the radar generator 1 is converged by a lens 2, the aspect ratio is adjusted by a prism 3, and the beam is directed onto a disk 6 via a half mirror 4 and a lens 5.

Here, at the time of daylight recording, the magnetic thin film is pre-aligned with an
The kiln mouth 4 is placed on a disk 6 which is magnetized in the same direction. This laser beam irradiation section is locally heated in a recording magnetic field of the magnet 8 in the Y direction, which is opposite to the X direction, so that the magnetization of this portion is reversed in the direction of the recording magnetic field (Y direction).

Next, during signal reproduction, the end of the sheath 11 of the sheath 11 generator 1 is irradiated onto the disk 6 via the above-mentioned path, and the radar light reflected from there is sent to the half mirror 9, the lens 10. The signal is supplied to a photodetector 12 via an analyzer 11 to be used as an information reproduction signal, and is also supplied to a photodetector 14 via a half mirror 9 and a lens 13 to be used as a tracking reference signal.

At this time, the polarization plane of the laser beam reflected from the disk 6 is reflected by the Kerr effect at a predetermined Kerr rotation angle depending on the magnetization direction of the disk magnetic thin film, and is converted into a predetermined signal current (2).

Now, considering the relationship between the sharpness of recording bits formed on the disc 6 during recording and the reproduced signal, the recording pits are as shown in FIGS. 2(A) and 2(B).

As shown in (C), the magnitude differs depending on whether the beam power is insufficient, appropriate, or excessive, respectively. Therefore, the reproduced signal also differs as shown in (D), '(E), and (F) of the same figure, respectively. The levels will vary depending on whether the beam power is insufficient, appropriate, or excessive. Now, record 1. +g is the same figure (B)
It is necessary to set the magnitude of the beam power so that recording bits of appropriate size shown in can be obtained.

However, even if the appropriate beam power is set, the sensitivity of each disk 6 is different, so the size of the pitch 1~ formed on the disk G will be different for each medium. becomes.

Conventional opto-thermal magnetic recording and reproducing devices do not take this point into consideration and record on all disks using one preset beam power, which has the disadvantage of not being able to obtain proper reproduction signals. Ta.

The present invention eliminates the above-mentioned drawbacks, and one embodiment thereof will be described with reference to FIG. 3 and subsequent figures.

FIG. 3 is a block system diagram in which an embodiment of the optical recording and reproducing apparatus according to the present invention is applied to a photothermal magnetic recording and reproducing apparatus, and FIG. 4 shows a flowchart 1 for explaining its operation. In FIG. 3, first, the recording mode is set (step 50), and then laser beams with different beam powers are emitted from the power variable laser generator 15, gradually increasing the beam power to each of the rotating disks 6 until it reaches a specified value. Irradiation is sequentially recorded on different positions (step 51). In this case, recording pits are formed on the disk 6, each having a different size depending on the magnitude of the beam power.

Next, the playback mode is set (step 52). disk 6
The reproduced laser beam obtained from the information signal regenerator 16 converts the reproduced laser light into a signal current according to the bit size,
A bandpass filter 1819 with a passband frequency fT is supplied to a bandpass filter 182 with a passband frequency 2fT,
A fundamental wave voltage e1 and its second harmonic distortion voltage e2 are extracted from these, respectively. Voltage e+, ez is the control circuit 22
It is supplied to the AD converter 21 via the switches 20+ and 202 which are switched alternately in a time-divisional manner by the switching signal from , where it is AD converted.Then it is supplied to the memory and arithmetic unit 22, where it is converted for each beam power. The information is sequentially stored in memory (step 53).

5- As shown in FIG. 5, the voltages e+ and e2 have their levels depending on the magnitude of the recording beam power, and the level of the voltage 02 is generally smaller than the level of the voltage e1, especially when the beam power P1 It becomes extremely small near . The memorized voltages 01 and 02 for each beam power are compared and calculated in the calculator 22, and the beam power P1 (digital value) is determined in which the voltage e1 is the maximum and the voltage e2 is the minimum.
(Step 54).

To determine the appropriate recording beam power, it is sufficient to find the period during which the voltage e1 is maximum, but since the beam power at which the voltage e1 is maximum has a certain range, it is difficult to determine the appropriate beam power from the voltage e1 alone. However, the voltage e1
The range of the beam power in which the voltage C2 is the maximum and the voltage C2 is the minimum is relatively narrow, so it is easy to find, and the second harmonic distortion is small. It is something that can be enjoyed. This beam power P1 is the appropriate recording beam power for the disc used.

6- The appropriate recording beam power determined by the arithmetic unit 22 is DΔ-converted by the DA converter 23 and converted into an analog value, which is then supplied to the variable power laser generator 15. In addition, the power variable laser generator 15 has an appropriate recording beam power P.
1 is set. When actually recording information signals on an ice black disc, the optimum recording beam power P1 for the disc used
Recording will be done at.

Next, a method for setting an appropriate recording beam power in consideration of tracking servo accuracy will be described.

The disk 6 is, for example, one in which a single tracking reference 114 for tracking servo is not formed, and the tracking reference signal S3 is obtained by a method called the three-point slotting method as shown in FIGS. 6(A) to 6(C). . That is, the information signal recording bits 24+ and 242 located before and after the information bind-off recording pit 24 to be reproduced are provided with an i~racking laser 1 light spot h2, which is different from the information signal reproduction 1 norther light spot 25.
6+262 is imaged, and the laser light that is reflected by q・1 is converted into electrical signals by detectors 271 and 272, and these are supplied to differential amplifier 12ε3 to obtain a tracking error signal, which is then used as a laser for reproducing information signals. The optical slots 1-25 are controlled so that they are always located at the center of the information signal recording pin 1-24 to be reproduced.

As shown in the same figure (B), when the 1~ ranking is off to the right (~25 is displaced to the right), the 1~ ranking is off to the right as shown in the same figure (C). 1~
The lagging error signals are respectively taken out.

a3, detection 327+, 272. Differential 7 7281.
:J: Figure 3 middle 1 ~ Rat King King Ra Shin @R/LLP
01, and 30 in FIG. 6 is a J information signal detector, which is a part of the information signal regenerator 16 in FIG.

However, in the case of 1 to racking error signal @V, a value where the recording beam power is larger than the appropriate value P1 is detected at a higher level. That is, as shown by the broken line in FIG.
] The racking error signal is extracted so much that the beam power becomes large.

Therefore, in this embodiment, the point where the voltage e1 and the 1~racking error signal VT are large is set as the optimum recording power without giving much consideration to the magnitude of the second harmonic distortion.

In FIG. 3, the voltage el and the e2° signal VT are switched by a switch 20+, which is switched by a switching signal from the control circuit 22.
A is supplied to the AD converter 21 via 202 and 203.
The data is converted into D and stored in the memory and arithmetic unit 22 (step 55 in FIG. 7). Next, in the computing unit 22,
An appropriate recording beam power P2 is determined in which the voltage 01 is in the maximum range and the signal VT is maximum (step 56).

In this way, if the tracking error signal VT is set to a large beam power P2 and the information signal is recorded using this, the accuracy of the tracking servo will be improved, and although the second harmonic distortion will increase somewhat, the overall performance will be improved. will improve.

Note that the device of the present invention is not only applicable to photothermal magnetic recording and reproducing devices; for example, a disc using a gold mH film as a recording medium is irradiated with a SEA 11 light spot, and the heat causes holes to be drilled or fouls to be formed. The same applies to optical recording and reproducing capacity where the ratio changes.

-〇- As described above, the optical recording/reproducing device according to the present invention sequentially generates recording laser beams with different beam powers from the recording laser generating means that can arbitrarily vary the beam power and the C11 generating means. recording means for sequentially irradiating and recording different positions of a rotating recording medium to form recording pits; By installing a reproduction means and a means for determining the appropriate recording beam power by determining the beam power value at which the fundamental wave reproduction voltage is maximum and the second harmonic distortion reproduction voltage is minimum, the appropriate recording beam power can be determined for each disc used. It is possible to record with a recording beam power, and it is possible to obtain a more appropriate raw signal than with conventional devices that record on any disc in the same way with a certain value of beam power set in advance, and also to record information. In particular, by reproducing the beep [- and setting the fundamental wave reproducing voltage and the tracking error signal, respectively, and setting the beam power value at which the tracking error signal is large in the range where the fundamental wave reproducing voltage is maximum as the appropriate recording beam power, 1~
It has the advantage that tracking servo can be applied with high precision on a disc that is not provided with racking reference signal pins 1 to 10 in advance.

[Brief explanation of the drawing]

Figure 1 is a schematic diagram of an example of a general device, and Figures 2 (A) to (
F) is a diagram for explaining the size of recording bits and reproduction signals that vary depending on the magnitude of beam power, FIG. 3 is a block diagram of an embodiment of the device of the present invention, and FIG. 4 is a diagram of one embodiment of the device of the present invention. A flowchart for explaining the operation of the embodiment, Fig. 5 is a characteristic diagram showing the relationship between recording beam power, reproduction output voltage and tracking error signal, and Figs. 6 (A) to (C) show the three-point spot method of the tracking servo. FIG. 7 is a flowchart for explaining the operation of another embodiment of the apparatus of the present invention. 6... Disk, 15... Beam power variable laser generator, 16... Information signal regenerator, 18+, 182
...Band filter, 21...AD converter, 22...
・Control circuit memory and arithmetic unit, 23...DA converter,
29...Tracking error signal 1 earthenware. 11-

Claims (2)

[Claims] (1) Recording Ray-I with arbitrarily variable beam power
J'' generating means, and a recording means that sequentially generates recording laser beams of different beam powers from the laser generating means and sequentially irradiates recording onto different positions of a rotating recording medium to form recording bits. and a reproduction means for reproducing the recorded bits to advance the parked fundamental wave reproduction voltage and the second harmonic distortion reproduction voltage, respectively; An optical recording and reproducing Si apparatus is characterized in that it comprises means for adjusting a certain beam power value to an appropriate recording beam power. (2) A recording laser generating means that can vary the beam power at will, and a rotating recording medium that sequentially generates recording laser beams of different beam powers from the four generating means. A recording means for sequentially irradiating and recording different positions to form information recording pins 1~, a reproducing means for reproducing the information recording pins 1~ to generate a fundamental wave reproduction voltage and a dragging error signal, respectively, and the fundamental wave reproduction. 1. An optical recording/reproducing apparatus comprising means for determining a beam power value at which the dragging error signal is large in a range where the voltage is maximum and adjusting the recording beam power to an appropriate recording beam power.