JPH0229941A - Optical information recording and reproducing device - Google Patents

Abstract

PURPOSE:To obtain a regenerative signal without any change attending upon the changeover of a light source by reproducing a rewrite-disable information recording part with erasing power for erasing information of a rewritable information recording part. CONSTITUTION:A reflected light L from a disk is incident upon a pin photodiode 2, and a photocurrent passes through a capacitor 3 to be inputted to an operation amplifier 5. At the time of normal reproducing, an analog switch 7 is open, and it is converted into a prescribed current value by a resistor 4. At the time of regenerating an address part by the erasing power, the switch is closed and the resistor 4 and a resistor 6 are connected in parallel, so as to decrease the converting amplification factor of the operation amplifier 5. By this method, the address part regenerated by the erasing power is also turned into the equivalent width to that as regenerated by regenerative power. Consequently, it is not necessary to change the light source over to another, and the regenerative signal without any change attending upon the changeover can be obtained, and then a dynamic range of a signal amplitude component can hence be reduced.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an optical information recording/reproducing device, and in particular, a first information recording section in which information cannot be rewritten and a first information recording section in which information can be rewritten. an optical information recording medium having a second information recording section, while reproducing information recorded on the first information recording section, erasing information recorded on the second information recording section; The present invention relates to an information recording/reproducing device.

[Prior Art] In recent years, in place of information recording and reproducing devices that use magnetic heads to record and reproduce information, optical information recording devices that use light beams to record at high density on optical information recording media and reproduce at high speed have been developed. Information recording and reproducing devices have been developed, and among them, optical information recording and reproducing devices using magneto-optical methods are rewritable, and the information is recorded by oriented the direction of magnetization in a certain direction on the disk. A laser beam spot is irradiated onto the recorded magnetic film, and the irradiated point is set to a temperature higher than the Curie temperature. When an external magnetic field is applied to this disk, only the points that reach the Curie temperature are changed in the direction of magnetization. Information is erased by directing the perpendicular magnetization in a certain direction by irradiating a laser beam that reaches the Curie temperature on the recording magnetic film in the erased area and applying an external magnetic field. It is something to do.

Information is reproduced by using the fact that the vibration plane of the reflected light rotates in the opposite direction depending on the magnetization direction of the part of the recording magnetic film of the disk that is hit by the laser beam, and the amount of rotation is determined by the intensity of the light. to obtain a signal. At this time, it goes without saying that the reproducing laser power is lower than the erasing laser power.

In addition, when recording information on a disk, it is necessary to record the track number and sector number of the track to be recorded on the disk in advance. This preformed information bit is then reproduced as a modulation of light intensity.

FIG. 4 is a circuit diagram showing a photoelectric conversion section of a reproduction system of a magneto-optical optical information recording and reproduction apparatus.

As shown in the figure, reflected light from the disk enters a pin photodiode 2 and is converted into a photocurrent. This photocurrent passes through a capacitor 3 and is applied to a resistor 4 by an op amp 5.
is converted to any voltage value.

5(a) to 5(C) are schematic explanatory diagrams for explaining the operation of the photoelectric conversion section of the reproduction system, and FIG. 5(a) is an explanatory diagram showing information tracks on the disk; Figure 5(b)
is a waveform diagram showing the change in laser power when erasing data,
FIG. 5(c) is a waveform diagram showing a reproduced signal when erasing data.

As shown in FIG. 5(a), on the optical information recording medium, there are address parts pt, P2, P3 in which track numbers etc. are recorded in advance, and data parts DI, D2, where the recorded data can be rewritten. D3 (Here, for simplicity, address parts P1 to P3. data part DI
-D3) are provided alternately, and the data portions DI, D2 of the optical information recording medium are provided alternately.
, D3, it is necessary to change the laser power as shown in FIG. 5(b).

This means that when reproducing the address part in an erase operation,
This is because when reading the address part, the normal reproduction power PR is used for reproduction, and after the address is confirmed, the erase power PH is changed to erase the data recorded in the data part.

[Problem to be Solved by the Invention] However, as shown in FIG. 5(C), the signal reproduced by the above erasing sequence has a response component corresponding to the change in laser power in addition to the information signal component, so the address The waveform changes greatly at the switching point between the section and the data section. In addition, the AC coupled amplifier of the photoelectric conversion unit as shown in Figure 4 causes a sag and the waveform is greatly distorted.The photoelectric conversion unit has to be AC coupled due to the relationship of the operating point, so it is regenerated by the erase sequence. In order to pass all changes in the signal, the dynamic range of the amplifier 5 shown in FIG. 4 must be made considerably larger than the information signal component. Therefore, it has been difficult to use an inexpensive amplifier, for example, an amplifier with one to three stages of individual transistors, as the photoelectric conversion section of a conventional optical information recording/reproducing device due to the dynamic range.

[Means for Solving the Problems] The optical information recording and reproducing device of the first invention of the present application includes a first information recording section in which information cannot be rewritten, and a second information recording section in which information can be rewritten. An optical information recording and reproducing device that erases information recorded in the second information recording section while reproducing information recorded in the first information recording section from an optical information recording medium having a recording section. The information recording device is characterized in that information recorded in the first information recording portion is reproduced using erasing power for erasing information recorded in the second information recording portion.

The optical information recording/reproducing device of the second invention of the present application is an optical information recording device having a first information recording section in which information cannot be rewritten and a second information recording section in which information can be rewritten. In an optical information recording and reproducing apparatus that erases information recorded in the second information recording section from a medium while reproducing information recorded in the first information recording section, the first information is erased by an erasing power. The present invention is characterized in that the amplification factor of the amplifier when reproducing the information recorded in the recording section is smaller than the amplification factor when reproducing the information recorded on the first information recording section using the reproducing power.

[Operation] The optical information recording/reproducing device of the first invention of the present application reproduces information recorded in the first information recording section using erasing power for erasing information recorded in the second information recording section. This eliminates the need to sequentially switch the light source between erasing power and reproducing power, and suppresses changes in the reproduced signal due to switching.

In addition to the above-mentioned effects, the optical information recording and reproducing device of the second invention of the present application has the advantage that when reproducing information recorded in the first information recording section by erasing power, the optical information recording and reproducing device according to the second invention The level of the output signal from the amplifier is adjusted by making the amplification factor of the amplifier when erasing information smaller than the amplification factor when reproducing information recorded in the first information recording section.

[Example] Hereinafter, an example of the present invention will be described in detail with reference to the drawings.

1(a) to 1(c) are schematic explanatory diagrams for explaining the operation of an embodiment of the optical information recording/reproducing device of the first invention of the present application, and FIG. 1(a) is a FIG. 1(b) is a waveform diagram showing changes in laser power during data erasing, and FIG. 1(C) is a waveform chart showing reproduction signals during data erasing.

As shown in FIG. 1(a), on the optical information recording medium there are address parts PI, P2,
P3 and the data section DI which becomes the second information recording section,
D2 and D3 are provided.

In addition, in the same way as in the conventional example described above, information is reproduced in the address part as a change in the light intensity of reflected light or transmitted light due to unevenness on the optical information recording medium, and in the data part, information is reproduced as a change in the light intensity of the reflected light or transmitted light due to the unevenness on the optical information recording medium. Information is reproduced by converting the amount of rotation of the vibration surface of the reflected light depending on the direction into a change in light intensity.

The feature of the present invention is that as shown in FIG. 1(b), the address part P1 is reproduced with the normal reproduction power PR.
After confirming the address of 1 and changing the erase power PE to erase the data recorded in the data section DI, the erase power PE is maintained as it is, and this erase power PH is changed to erase power PE.
The laser beam reproduces the address section P2 and the data section D2.
The purpose is to sequentially erase the data recorded in the address section P3, reproduce the address section P3, and erase the data recorded on the data section D3.

When erasing sectors continuously like this, if you erase the data part and reproduce the address part with the erase power PH maintained at the erase power PH from the time the first address is confirmed until the completion, the first
As shown in figure (C), from the address part P1 to the data part D
At the point where the laser power changes when moving to I, the waveform swings downward, but it recovers by the time the next address arrives, and the amplitude of the address part read by the erase power PE is read by the reproduction power PR. Although the amplitude is larger than that of the address section, the large fluctuation at the switching point between the address section and the data section as shown in FIG. 5(C) is eliminated.

The difference in amplitude between the address section read with the erase power PE and the address section read with the reproduction power PR can be resolved by adjusting the amplification factor of the amplifier.

FIG. 2 is a circuit diagram showing an embodiment of the photoelectric conversion section of the reproducing system of the optical information recording/reproducing apparatus according to the second invention of the present application.

As shown in the figure, reflected light from the disk is incident on a bin photodiode 2 and converted into photocurrent. This 'tfii passes through a capacitor 3 and is converted into a voltage by an operational amplifier 5. A resistor 4 is connected in parallel between the reflective input terminal and the output of the operational amplifier 5, and a resistor 6 is connected in parallel.
are connected in parallel via the analog switch 7.0 During normal playback (playback power), the analog switch 7
is open and the photocurrent is converted into a predetermined voltage value by the resistor 4. When reproducing the address section with erase power,
Analog switch 7 is opened to connect resistor 4 and resistor 6 in parallel between the inverting input terminal and output of operational amplifier 5, thereby reducing the conversion gain of the amplifier. In other words, when the address part is reproduced with erase power, the photocurrent of the signal component increases, but by setting the conversion amplification factor of the amplifier to an appropriate value, the processing amplitude of the output signal of the amplifier can be made the same. For example, when the erasing power is 10 times the reproduction power, if the conversion amplification factor when using the erasing power is set to 1/10 of that when using the reproduction power, the address section reproduction signal amplitude will be the same.

3(a) to 3(c) are schematic explanatory diagrams for explaining the operation of an embodiment of the optical information recording/reproducing apparatus of the second invention of the present application, and FIG. 3(a) is a disc An explanatory diagram showing the information track above, Figure 3(b) is a waveform diagram showing changes in laser power when erasing data, Figure 3(c) is a waveform diagram showing changes in the amount of incident light, and Figure 3(d) is a waveform diagram showing changes in the amount of incident light. ) is a waveform diagram showing a switching signal of an analog switch. FIG. 3(e) is a waveform diagram showing a reproduced signal when erasing data.

As shown in FIG. 3(a), on the optical information recording medium there are address areas Pi, P2, P3 and a hitator area DI.
, D2, and D3 are provided. As shown in FIG. 3(b), the address section P1 is reproduced with the normal reproduction power PR to confirm the address of P1.

Next, in order to erase the data recorded in the data section D1, the erase power is changed to PH, and then the erase power is changed to PE as it is.
is held, and with this laser beam of erasing power PH, the address section P2 is reproduced, the data recorded in the data section D2 is erased, the address section P3 is reproduced, and the data recorded in the data section D3 is erased in this order. After the last address is confirmed, the reproduction power is returned to PR. At this time, the third
As shown in Figure (C), the signal light intensity of the address P1 read with the reproduction power PR is input R, and the signal light amount of the address P2 read with the erase power PE. The signal light amount of P3 is λE.

The switching signal of the analog switch shown in Fig. 3(d) is
Changes in synchronization with the laser power, and when the laser power is the reproduction power PR, the analog switch 7 is in the "L" state.
is in an open state, and when the laser power is the erase power PH, it is in an "H" state and the analog switch 7 is in a closed state. In this way, the analog switch 7 is controlled, and the amplification factor of the amplifier is controlled.

By adjusting the values of resistor 4 and resistor 6, the input R/
If the rate of change is lowered by the ratio of λE, as shown in FIG. 3(e), the address portion reproduced with the reproduction power PR and the address portion reproduced with the erase power PE will have the same amplitude.

[Effects of the Invention] As explained above in detail, according to the optical information recording/reproducing device of the first invention of the present application, unnecessary amplitude fluctuations of the reproduced signal are suppressed, and the dynamic range of the signal amplitude component is further reduced. Therefore, it is possible to use an inexpensive amplifier.

Further, according to the optical information recording/reproducing device of the second invention of the present application, in addition to the above-mentioned effects, even if the first information portion is reproduced, it is processed with an equivalent amplitude value using both the reproduction power and the erasing power. I can do things.

[Brief explanation of the drawing]

FIGS. 1(a) to 1(C) are schematic explanatory diagrams for explaining the operation of an embodiment of the optical information recording/reproducing apparatus of the first invention of the present application. FIG. 2 is a circuit diagram showing a photoelectric conversion section of a reproducing system of an embodiment of the optical information recording/reproducing apparatus according to the second invention of the present application. FIGS. 3(a) to 3(e) are schematic explanatory diagrams for explaining the operation of an embodiment of the optical information recording/reproducing apparatus of the second invention of the present application. FIG. 4 is a circuit diagram showing a photoelectric conversion section of a reproduction system of a magneto-optical optical information recording and reproduction apparatus. FIGS. 5A to 5C are schematic explanatory diagrams for explaining the operation of the photoelectric conversion section of the reproduction system. P1 to P3 Near address section, D1 to D3: Data section, PR: Reproduction power PE: Erase power 2: Pin photodiode, 3: Capacitor, 4.6:
Resistor, 5 niobium amplifier, 7: Analog switch.

Claims (2)

[Claims] (1) From an optical information recording medium having a first information recording section on which information cannot be rewritten and a second information recording section on which information can be rewritten, to the first information recording section. In an optical information recording and reproducing device that erases information recorded in the second information recording section while reproducing the recorded information, an erasing power that erases the information recorded on the second information recording section is used. An optical information recording/reproducing device characterized in that it reproduces information recorded in a first information recording section. (2) From an optical information recording medium having a first information recording section on which information cannot be rewritten and a second information recording section on which information can be rewritten, to the first information recording section. In an optical information recording and reproducing device that erases information recorded in the second information recording section while reproducing recorded information, when reproducing information recorded in the first information recording section using erasing power; 1. An optical information recording and reproducing device, characterized in that the amplification factor of the amplifier is smaller than the amplification factor when reproducing information recorded in the first information recording section using the reproducing power.