JPH02172045A - Magneto-optical disk device and magneto-optical disk used therefor - Google Patents

Abstract

PURPOSE:To improve the quality by switching properly information formed in pits and a signal of a data area due to the magneto-optical effect other than the header area. CONSTITUTION:A header part and a flag part are provided at a special period on a magneto-optical disk 1 and a header part timing signal T1, a bit flag timing signal T2 and a recorded flag timing signal T3 synchronously with the period are easily generated by the pattern matching. In the disk where information recorded by the different systems in such a way exists in mixture, a selection circuit 6 can output an output signal 41 (sum signal) of a sum signal circuit 4 from the header part, output an output signal (difference signal) 51 of the difference signal circuit 5 in the data are utilizing the magneto-optical effect and the sum signal 41 is outputted in the data area recorded with the information by forming pit strings in advance. Since the signal is selected by placing priority on the flag of the signal 41, the effect due to pits appears on the signal 51, the signal is selected without mistake, thereby improving the operation stability and improving the quality.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a magneto-optical disk device and a magneto-optical disk used therein, and particularly relates to an information recording/reproducing portion using the magneto-optical effect and a magneto-optical disk. Related to a magneto-optical disk having a pre-recorded portion formed by a pit array, etc., and a magneto-optical disk device suitable for reproducing the magneto-optical disk [Prior art] A conventional magneto-optical disk device is disclosed in Japanese Patent Application Laid-Open No. 1989-1999. -156047
As described in the publication, means for reproducing information formed of bits such as header information, and means for reproducing data areas recorded using magneto-optical effects other than the header area are separately provided, After matching the levels of both signals, they were added to form one reproduced signal.

[Problem to be solved by the invention]

The above-mentioned conventional technology does not take into consideration the mutual influence between the signal reproduced from the data area using the magneto-optical effect and the signal reproduced from the header area formed of bits. For this reason, in the conventional technology, when reading data formed by bits, etc., the output signal of the signal reproducing means using the magneto-optical effect is affected by the effects of birefringence of the magneto-optical disk substrate and reflections caused by The effect of changes in the amount of light appears as noise, and the noise is added to the signal that reproduces the data formed by bits, etc., so there is a problem that the reliability of the signal decreases.'1JIc1 of the present invention
The purpose of this is to create a magneto-optical disk device that can reproduce data (information) formed by bits, etc. and data recorded using the magneto-optical effect in a high-quality state.
Our goal is to provide the following.

A second object of the present invention is to provide a magneto-optical disk that can be effectively used in the magneto-optical disk device t, which can reproduce information in a high quality state.

[Means to solve the problem]

For the first purpose mentioned above, use a signal that reproduces information formed by bits such as header information, and a signal that reproduces data areas recorded using magneto-optical effects other than the header area, by appropriately switching between them. This is achieved by

The signal reproduced from the magneto-optical disk is demodulated or decoded, and in some cases undergoes processing such as error correction before being output from the device. As a place to switch and select signals,
(1) Before demodulation/decoding, (2) After demodulation/decoding, (
3) Furthermore, there is no problem whether it is done after the subsequent processing, etc., but if the switch is made close to the reproduction equal signal from the magneto-optical disk, there will be less redundant circuits.On the other hand, later The more the signals are switched, the more standardized the signals become, making selection and integration easier. For example, a controller that controls the magneto-optical disk device 11 can determine which method the data is on the magneto-optical disk. One possible method would be to read the management information (in which the power is recorded) from the magneto-optical disk in advance and switch the reproduction means based on that information.However, in this case, each time the signal is reproduced, the reproduction point is It must be determined by referring to the management information whether the
In addition to requiring a storage area to store the management information, processing time for reference and determination is added each time a signal is reproduced.

Therefore, it is desirable that signal switching be performed automatically during signal reproduction.

Here, if the information is formed by bits, etc. and exists periodically like header information and its position is known in advance, it is possible to create a timing signal synchronized with the corresponding area. This allows the signal to be switched. On the other hand, in the data area, a part where data is formed using bits etc. during magneto-optical disk molding and a part where data is recorded and reproduced using the magneto-optical effect are mixed in an arbitrary arrangement, and a valid signal is output. By selecting which one to use, you can obtain the correct signal.

Methods for detecting a valid signal include (1) recording (forming) information that identifies both; (2) validating the one that conforms to demodulation/decoding rules among both signal reproduction means;
(3) Among both signal reproducing means, the one with fewer errors as data is made effective.

Furthermore, if both are determined to be valid, a priority order is set so that a signal obtained from a means for reproducing information formed of bits or the like is selected.

Above I! The purpose of No. 2 is to record and reproduce the first information.
A second area in which second information is recorded in advance by providing a shape such as a bit to be changed by incident light t supplied from the outside and reflected light i resulting from the incident light t, and a first area
and the second area, respectively, the recorded first . A fifth area is provided in which a flag indicating the presence or absence of the second information is recorded, and a third area corresponding to the second area is pre-recorded with the second information in the form of a bit or the like. [Operation] In order to switch and use the signals obtained from the two signal reproducing means, the flag is output when the respective first and second signal reproducing means are not operating. No signal affects the other signal in operation.

In addition, even if the first signal reproducing means that reproduces a signal using the magneto-optical effect is affected by a part where data is formed with bits, etc. and generates some kind of signal, it will not reproduce the data formed with bits, etc. Because priority is given to the signal obtained from the means for

〔Example〕

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a magneto-optical disk mounting according to the present invention and a magneto-optical disk used therein will be explained in detail with reference to the drawings.

FIG. 1 shows -, l! of the magneto-optical disk device of the present invention. FIG. 2 is a diagram illustrating an embodiment, and is a diagram illustrating the configuration of a data reproducing system.

In FIG. 1, a laser beam emitted from a semiconductor laser 51 is collimated by a lens 52 and then sent to a first beam splitter 55. The light passes through the pickup 2 and is irradiated onto the magneto-optical disk 1 . The reflected light from the magneto-optical disk 1 passes through the pickup 28 to the first beam splitter 3S.
42 further beam splitters 54
The light is separated into reflected light and transmitted light, one of which is guided to the first photodetector 36 via the first polarizing plate 558, and the other is guided to the second photodetector 3B via the polarized light of g2 &37. 1st
The polarizing plate 55 and the second polarizing plate 57 are arranged at +45° and -45', respectively, with respect to the incident light.

The above semiconductor laser 31. Lens 32. First beam sinter 55. Second beam splitter 54. First polarizing plate 35. Polarizing plate 37.4 of first photodetector 56.42
The optical detector 38 and the pickup 2 are arranged on the chassis as the original head 6. Note that this optical head 3 is movable in the left-right direction in FIG. The pickup 2 is equipped with an objective lens that is movable in the vertical and horizontal directions of FIG. 1 along with a driving device in those directions (not shown). It is designed to focus laser light on the track.

First photodetector 56 of optical head 5. Second photodetector 5B
The output signals from the rl are input to the sum signal circuit 4 and the difference signal circuit 5, respectively. The sum signal circuit 4 outputs #! A first sum signal, which is a signal obtained by adding the output signal of the first photodetector 36 and the output signal of the second photodetector 5B, is output.

The first sum signal indicates a change in the amount of light reflected from the magneto-optical disk 1. The difference signal circuit 4 outputs a difference signal 51 that is a difference signal between the output signal of the first photodetector 56 and the output signal of the second photodetector 58. The difference signal 51 is a zero sum signal that indicates a change in the magnetization direction by utilizing the magneto-optical effect in which the polarization angle of reflected light changes depending on the magnetization direction of the recording film (not shown) of the magneto-optical disk 1. The respective output signals of the circuit 4 and the difference signal circuit 5 are selected by the selection circuit 6 and outputted. I will explain.

FIG. 2 is a diagram showing an embodiment of the magneto-optical disk of the present invention, and is also a schematic diagram showing its data tracks.

In FIG. 2, data tracks 16 are formed concentrically or spirally on the magneto-optical disk 1. As shown in FIG. As shown on the right side of FIG. 2, each data track 16 includes a header section 17 in which address information etc. are recorded, a data area 19 in which data is recorded, and a flag indicating the presence or absence of data in the data area 19. It consists of a flag section 18. In the head section 17, address information and the like are formed in advance as pits 11 at the time of disk production. Data area 1
Normally, pits etc. are not arranged on the magneto-optical disk 9.
Information is recorded by causing a thermo-magnetic change in the recording film, and the information is reproduced by the magneto-optical effect.

FIG. 2(a) shows a state in which a changed portion occurs due to recording of information. In addition, FIG. 2(b) shows the data area 19
The output signal of the sum signal circuit 4 and the output signal of the difference signal circuit 5 at 0 or more are shown in FIG.
) is shown. That is, in the portion where pits have been formed in advance, a signal change portion corresponding to the pitch H occurs in the output signal of the sum signal circuit 4, and appears as a slight noise in the output of the difference signal circuit 5. On the other hand, in the part where information is reproduced by the magneto-optical effect, only the output signal of the difference signal circuit 5 changes, and no change appears in the output signal of the sum signal circuit 4.C Next, the main part of the present invention. A first embodiment of the selection circuit 6 will be described with reference to FIG.

FIG. 3 is a block diagram showing the configuration of the selection circuit 6 shown in FIG. 1.

In FIG. 3, the first comparator 611 outputs a signal level 11'' when the first sum signal changes by a certain level or more, and outputs a signal level ``0'' when there is no change.The first latch 612 latches the output signal of the first comparator 611 with the pit flag timing signal T2. Similarly, the second comparator 615 latches the output signal of the first comparator 611 with the pit flag timing signal T2.
When the value changes over a certain level, it outputs 11", and when there is no change, it outputs '0". A second latch 614 latches the output signal of the second comparator 616 with the recorded flag timing signal -l'FT5. AND
The circuit 66 outputs "0" only when the output signal of the first latch 612 is 10" and the output signal of the second latch 614 is 11", and otherwise outputs "1".
The OR) circuit 67 outputs 11'' when the output signal of the AND circuit 66 is '1'' or the header timing signal T1 is 11''. Output. The multiplexer circuit 615 outputs a sum signal 18th and a time difference signal of % 3 // when the output of the OR circuit 67 is 11''.

Next, the operation 7i of the selection circuit 6 with the above configuration will be explained using FIGS. 3 and 4.

FIG. 4 is a diagram showing changes in each signal of the selection circuit 6.

In FIG. 4, the data area 19 of the data track 16
There are a data area 19a in which information is recorded using the magnetization direction changing portion 13 of the recording film, and a data area 19b in which information is recorded by forming a bit string 15 in advance. In the flag portion 18a preceding the data area 19m, there is a recorded flag 12 recorded by changing the magnetization direction of the recording film during information recording.

Further, in the flag portion 18b preceding the data area 19b, a bit flag 1 formed at the time of creating the magneto-optical disk is included.
There are 4.

In the header section 17, the header section timing signal T1
becomes '1'', so the selection circuit 6 outputs the sum key number 1.

In the flag unit 18a, the recorded flag 1 is set only for the first difference signal.
2 Changes due to IC appear. Therefore, the second comparator 613 outputs '1', and the second latch 614 latches and outputs '1' with the recorded flag timing signal T3. On the other hand, since no change appears in the first sum signal, 1. The comparator 611 of cave 1 outputs ``0'', and the first latch 612 latches ``0'' with the bit flag timing signal T2. The AND circuit 66 therefore outputs ``0'', and the output signal of the OR circuit 67 becomes 10'' in the data area 19a where T1 is ``0'', so the multiplexer 615 outputs the difference signal 51.

In the flag section 18b, a change due to the bit flag 14 appears in the sum signal 51, the first comparator 611 outputs 11", and the first latch 612 latches and outputs '1" at the bit flag timing 100 T2. do.

Therefore, the AND circuit 66 outputs '1', and even in the data area 19b where T1 is '0', the multiplexer 6
15 outputs the first sum signal. At this time, the influence of the bit on the difference signal 51 is caused by the comparator 615 of the current n1ka2.
, @2 outputs '1', the output signal of the AND circuit 66 is '1'. Therefore, the output signal of multiplexer 615 remains the first sum signal.

Note that the header section 17 and the flag section 18 are provided on the magneto-optical disk 1 at specific known intervals.

The header timing signal TI and pit flag timing deviation T2° recorded flag timing signal T6 synchronized with these cycles can be easily generated by pattern matching or the like.

As described above, the selection circuit 6 outputs the first output signal (sum signal) of the sum signal circuit 4 to the magneto-optical disk 1 on which information recorded in different methods is mixed. (2) Data area using magneto-optical effect 19
In a, the output signal (difference signal) 51 of the difference signal circuit 5 can be outputted, and (3) in the data area 19b where information is recorded by forming a bit string 158 in advance, the output signal (difference signal) of the sum signal circuit 4 can be outputted.
(sum signal) can be output.

According to this embodiment, since a signal is selected with priority given to the flag that appears first in the sum signal, a signal can be selected without error even if the difference signal 51 is affected by bits, so the stability of operation is improved. do.

Further, according to this embodiment, since the circuits for the sum signal and the difference signal are equivalent to a comparator and a latch, it is possible to reproduce a magneto-optical disk containing a mixture of information recorded by different methods using a small-scale circuit.

Next, a second embodiment of the selection circuit 6 of the magneto-optical disk device according to the present invention will be described with reference to FIG.

@Figure 5 is a block diagram showing the configuration of selection circuit B.

In FIG. 5, the first decoding circuit 621
is a decodable signal, the first sum signal is decoded into data and inputted to the first FIFO (first-in-first-out circuit) 625, and a pulse is sent to the first counter circuit 622 for each byte. send. Sum signal 1st
If the signal cannot be decoded because it deviates from the modulation/encoding regularity, the undefined data is transferred to the first FI.
The pulse is input to the F O 625, and no pulse is sent to the first counter circuit 622. First counter circuit 62
2 is the header timing signal T1 with a count value of 80,
Thereafter, the count is increased by the pulse sent from the first decoding circuit 621. Then, when the count value exceeds a predetermined value, 11" is output. That is, the sum signal number from the beginning of the data area 19 is 18 decoding is performed, and if data that can be decoded (correctly modulated and encoded) by -constant or more is obtained, '1' is output to the AND circuit 66.

Similarly, when the difference signal 51 is a decodable signal, the second decoding circuit 625 decodes it into data and sends it to the second FI.
Input to FO626 and second counter circuit 6
24 for each byte. Then, the counter circuit 624 of g2 sets the count value to 80 by the header timing signal T1, and counts up by the pulse sent from the second decoding circuit 625. Furthermore, if the count value exceeds a predetermined value, '1' is output. In other words, the difference signal 51 is decoded from the beginning of the data area 19, and when a certain number or more of decodable data is obtained, '1' is output to the AND circuit 66.

Then, the first FIFO 625 and the second FIFO
Each of the output signals 626 is input to a data selection circuit 68. When the output signal of the AND circuit 66 is '1', the data selection circuit 68 selects data obtained by decoding the output signal of the F I F 0623 (i.e., the first sum signal) of w,1.
When the output signal of the ND circuit 66 is 10", the second PIF"
The data obtained by decoding the output signal of 0626 (that is, the difference signal 51) is read out and output. AND circuit 66
In this case, the output signal of the first counter circuit 622 is '0'' and the output signal of the second counter circuit 624 is '1''.
The data selection circuit 68 outputs ``0'' only when
If the sum signal 1 is a decodable signal, the data obtained by decoding the first sum signal can be output, and if the difference signal 51 is a decodable signal, the data obtained by decoding the difference signal 51 can be output. At this time, data cannot be selected while the first counter circuit 622 and the second counter circuit 624 are counting the decodable data, so the sum signal 1, the difference signal 51, and the decoded data 8 FIFO 625 and second PIFO 626
The data selection circuit 68 reads out the data after counting is completed.

According to this embodiment, since it is possible to select an effective one of the two reproduced signals without using a flag, there is no need to provide a flag area, and there is an effect of eliminating redundancy.

Further, according to this embodiment, since the decodability is determined from data of 8 or more bytes, it is possible to prevent erroneous selection due to dust, scratches, etc., thereby improving reliability.

Next, a third embodiment of the magneto-optical disk storage selection circuit 6 according to the present invention will be described with reference to FIG.

FIG. 6 is a block diagram showing the configuration of the selection circuit 6. As shown in FIG.

In Fig. 6, the first sum signal is sent to the first decoding circuit 621.
and sends the data to the first error correction circuit (first EC
C circuit) After correcting the data error in 633, the first R
Data is stored in AM (random access memory) 635. Here, the first ECC circuit 633 outputs '1' to the AND circuit 66 when the input data has no error or is error correctable data, that is, when valid data is obtained. Similarly to the first sum signal, the difference signal 51 is decoded into data by the second decoding circuit 625, and after data errors are corrected by the second ECC circuit 634, it is stored in the second RAM 656. The ECC circuit 634 of J2 outputs the AND circuit 6 when the input data has no errors or is error-correctable data.
'1' is output to 6.

The data/event selection circuit 68 outputs the data of the first RAM 655 (that is, the data obtained by decoding and correcting the first sum signal) when the output signal of the AND circuit 66 is '1';
When the output signal of AND circuit @66 is '0'', the second R
A M 636 data (that is, data corrected after decoding the difference signal 518) is output. The AND circuit 66 outputs % o // wo only when the input signal from the first ECC circuit 655 is 10" and the input signal from the second ECC circuit 634 is '1", and otherwise ``1''
Output. Therefore, the data selection circuit 6th selects the sum signal 1st.
When valid data is obtained from the sum signal 1, the data obtained by decoding and correcting the first sum signal is output, and when valid data is obtained from the difference signal 51, the data obtained by decoding and correcting the difference signal 51 is output. do.

According to this embodiment, since the validity of data is confirmed by one error correction circuit, a highly reliable determination is possible, and there is an effect of improving reliability.

Next, a fourth embodiment of the selection circuit B of the magneto-optical disk device according to the present invention will be described with reference to FIG.

FIG. 7 is a block diagram showing the configuration of the selection circuit 6.

In FIG. 47, the first decoding circuit 621 receives the sum signal first
is a decodable signal, decode it to data and $
When the 0-sum signal 1, which is input to F I F 0625 of 1 and sends a pulse for each byte to control circuit 6 3, is a signal that cannot be decoded because it deviates from the modulation/encoding rules, etc. , undefined data to the first F"IFO62
5, and no pulse is sent to the control circuit 645. Similarly, when the difference signal 51 is a decodable signal, the second decoding circuit 625 decodes it into data and inputs it to the second FI F 0626.
45 for each byte.

The first flag detection circuit 6 of 81!1 is composed of a first comparator 611 and a gl latch 612 in the first embodiment shown in FIG. 14 is detected, and when the pit flag 14 is detected, it sends '1' to the third control circuit 6.Similarly, the second flag detection circuit 642 connects the 8g2 comparator 616 and the second The recorded flag 128 is detected from the difference signal 51, and when detected, it sends '1' to the control circuit 646. 1st FI
The output signals of the F 0625 and the second PI FO 626 are respectively supplied to the data selection circuit 6B, and the data selection circuit 68 selects the first PI FO 625 when the third output 1M of the control circuit 6 is "1". The control circuit 645 outputs the data obtained by decoding the output signal (that is, the first sum signal).
When the output signal of the second F I F O62 is 10"
The data obtained by decoding the output signal of No. 6 (ie, the difference signal 51) is output.

The control circuit 645 counts n pulses supplied from the first decoding circuit 621 and the second decoding circuit 625, respectively, and makes the one that exceeds a predetermined value first valid. For example, when the number of pulses from the first decoding circuit 621 exceeds a predetermined value first, the first decoding circuit 621 is enabled. Furthermore, the control circuit 645 controls the first flag detection circuit 6
and#! The output signal to the data selection circuit 68 is determined from the signals obtained from the two flag detection circuits 642 and the determination result from the count value described above. Control circuit 64
An example of the decision logic for the output signal of No. 5 (truth table) 8 is shown in Table 1.

Table 1 Based on this logic, the data selection circuit 68 selects and outputs the data obtained by decoding the first sum signal and the data obtained by decoding the difference signal 51.

According to this embodiment, the data to be output can be selected based on two criteria: the flag and the decodability of the signal.
It is possible to reduce erroneous judgments due to dust, scratches, etc., and is effective in improving reliability.

Next, a fifth embodiment of the selection circuit 6 of the magneto-optical disk device 11 according to the present invention will be described with reference to FIG.

FIG. 8 is a block diagram showing the configuration of the selection circuit 6.

The first decoding circuit 621 decodes the sum signal No. 18 and sends the data to the first comparison circuit 651 and the data selection circuit 68. The first comparison circuit 651 moratches the data using the bit flag timing signal T2, and outputs '1' to the AND circuit 66 if it matches the predetermined data.Similarly, the second decoding circuit 625 The signal 518 is decoded and sent to the second comparison circuit 652 and data selection circuit 68.The second comparison circuit 652 detects the data using the recorded flag timing signal T3, and if it matches the predetermined data, AND circuit 664 outputs "1".

In the data selection circuit w668, the output signal of the AND circuit 66 is 1.
1", outputs the data obtained by decoding the first sum signal, and
When the output signal of the ND circuit 66 is '0'', the data obtained by decoding the difference signal 51 is outputted. '''0 only when the output signal of the circuit 652 is 11''
", and otherwise outputs V"1".

On the 1st day of the flag section of the magneto-optical disk 1, if data is previously formed in the data area j9 using pits, predetermined data is formed in the flag section tab using bits, etc. When recording data using magnetic changes in the recording film surface, data determined in the flag portion 18a is recorded by the magnetic changes. here,
A flag (bit flag 14) formed in advance with bits,
Different data is used for the flag to be recorded later (recorded flag 12).

As a result, the data selection circuit 68 outputs data decoded from the sum signal 1 in the data recording section based on changes in the amount of reflected light due to bits, etc., and outputs data decoded from the difference signal 51 in the data recording section using the magneto-optical effect. .

According to this embodiment, since flag detection is performed using different data, the two recording methods can be reliably identified, which is effective in improving reliability.

〔Effect of the invention〕

According to the present invention, a reproduction method using the magneto-optical effect is applied to a magneto-optical disk in which a data recording portion in which data is recorded by a change in the direction of magnetization and a data recording portion in which data is recorded by a change in the amount of reflected light itself coexists. Since data is reproduced by switching between a reproduction method that uses changes in the amount of reflected light and a reproduction method that uses changes in the amount of reflected light, it is possible to prevent one signal from having an adverse effect on the other as noise, improving data reliability and maintaining high quality. It is possible to provide a magneto-optical disk device that can play back data.

Note that, according to the present invention, since the reproduction method can be automatically switched, there is also the effect of improving convenience.

Further, it is possible to provide a magneto-optical disk that can be effectively used in a magneto-optical disk device that can reproduce information in a high-quality state as described above.

Note that the present invention assumes a magneto-optical disk in which a data recording portion that utilizes the magneto-optical effect and a data recording portion that utilizes changes in the amount of reflected light coexist.
Similarly, the present invention can be applied to a device in which a plurality of mutually exclusive reproduction methods coexist, and can also be applied to other recording media.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the reproduction system of the first embodiment of the magneto-optical disk device of the present invention, FIG. 2 is an explanatory diagram for explaining the operation of the embodiment of the dXl of the present invention, and FIG. A block diagram showing an example of the first /1aIs selection circuit in the first embodiment of the magneto-optical disk device of the present invention,
5 is a block diagram showing the selection circuit according to the second embodiment of the present invention, and FIG. 3 is a block diagram showing the selection circuit according to the third embodiment of the present invention. FIG. 7 is a block diagram showing a selection circuit in a fourth embodiment of the invention, and FIG. 8 is a block diagram showing a selection circuit in a fifth embodiment of the invention. 1... magneto-optical disk, 5... optical head, 4...
sum signal circuit, 5...M signal circuit 26...selection circuit, 12...recorded flag 14...pit flag, 615 river multiplexer 66...AND circuit, 621 river first decoding circuit, 625... Second decoding circuit 68... Data selection circuit, 655... First ECC
Circuit 664...Second FCC circuit, 645...Control circuit, 6th...! 11 flag detection circuits. 642...Second flag detection circuit, 651...First comparison circuit, 652...Second comparison circuit.・-゛Representative Patent Attorney Katsu Isamu Ogawa ”,）Fig.

Claims (1)

[Scope of Claims] 1. In a magneto-optical disk device that records and reproduces information on a predetermined magneto-optical disk using the magneto-optical effect, first information is read from the magneto-optical disk using the magneto-optic effect. and a second signal reproducing means that reproduces second information from the magneto-optical disk by utilizing changes in the amount of light depending on the shape of bits etc. provided in advance on the magneto-optical disk. a first detecting means for determining whether the output signal of the first signal reproducing means is valid and detecting a valid signal; and whether the output signal of the second signal reproducing means is valid. a second detecting means for determining whether or not the signal is valid and detecting a valid signal; and selecting one of the output signals of the first and second signal reproducing means based on the output signals of the first and second detecting means. What is claimed is: 1. A magneto-optical disk device comprising a selection output means for outputting a selected image. 2. In a magneto-optical disk on which first information is recorded and reproduced using the magneto-optical effect, the first area where the first information is recorded and reproduced and the reflection caused by the incident light supplied from the outside. A second area in which second information is recorded in advance by providing a shape such as a bit that changes the amount of light, and corresponding to each of the first area and the second area, at least one third area in which a flag indicating the presence or absence of the recorded first and second information is recorded;
A magneto-optical disk characterized in that a second flag is recorded in advance in the third area corresponding to the second area by providing a shape of the bit or the like. 5. A first flag is recorded in the third area corresponding to the first area using magneto-optical effect, and the recording position of the first flag and the recording position of the second flag are different. 3. The magneto-optical disk according to claim 2, wherein the magneto-optical disk is different from the above. 4. The magneto-optical disk according to claim 2, further comprising a first signal recording means for recording the first information using a magneto-optical effect, and the first signal recording means is configured to record the first information using the magneto-optical effect. When recording the first information, the first detecting means records a detectable first flag in the third area, and the first detecting means is effective depending on the presence or absence of the first flag. 2. The second detecting means detects a valid signal based on the presence or absence of the second flag recorded in advance in the third area of the magneto-optical disk. The magneto-optical disk device described in . 5. With respect to the magneto-optical disk according to claim 3, the first detection means detects the presence or absence of the first flag and determines whether the output signal of the first signal reproduction means is valid or not. and the second detection means detects the presence or absence of the second flag to determine whether or not the output signal of the second signal reproduction means is valid. The magneto-optical disk device according to claim 1. 6. The plurality of first detection means, the plurality of second detection means, and the first and second signal reproducing means based on the output signals of the plurality of first and second detection means. 2. The magneto-optical disk device according to claim 1, further comprising: said selection output means for selecting and outputting one of the output signals. 7. Claim 1, further comprising the selection output means that selects and outputs the output signal of the second signal reproduction means when both the first and second detection means are determined to be effective. The magneto-optical disk device described in .