JPH05266593A - Optical disk - Google Patents

Abstract

PURPOSE:To provide an optical disk device capable of discriminating the format of the optical disk with a simple configuration. CONSTITUTION:A format is discriminating detecting an identifying mark using a reproducing signal from an optical disk 1. A detected parameter is set up on an identifying mark detecting means 3 by a CPU 6 when a disk format having a specified number of sectors in a track is imagined. The identifying mark is detected from the reproducing signal by the identifying mark detecting means 3 based on this detected parameter. However, when the optical disk 1 is provided with a format different from the imagined disk format, no normal detection of the identifying mark is operated. The provision of the imagined disk format on the optical disk 1 is discriminated by the CPU 6 based on the existence of a detecting signal from the identifying mark detecting means 3 within a certain time.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical disk device having a function of discriminating a recording format of an optical disk.

[0002]

2. Description of the Related Art Conventionally, there has been known an optical disk device which records or reproduces information by irradiating a rotating optical disk with a laser beam. In such an optical disc, a plurality of tracks are usually formed as concentric circles or spirals as an information recording area. Each track is divided into areas called sectors. Recording and reproduction of information on such an optical disc are generally performed in sector units. Each sector is provided with a sector mark indicating the start position of the sector. When information is recorded / reproduced on / from the optical disc, the sector mark is detected by detecting the sector mark, and information is recorded / reproduced on / from the sector.

FIG. 4 is a diagram schematically showing an optical disc having a spiral track. In FIG. 4, the area of one track (one track) is divided into eight sectors. Regarding the number of sectors to divide a track, a format that divides one track into 1024 sectors and a format that divides into 512 sectors are generally used.

As described above, when there are optical discs having different sectors per track, that is, optical discs having different formats, in order to correctly perform recording / reproducing for each optical disc, the optical disc device has to It is necessary to recognize which format the optical disk of is. Therefore, conventionally, the optical disc or the cartridge containing the optical disc is provided with a mark or a hole for discriminating the format. When the optical disk is inserted, the optical disk device detects the mark or hole by the sensor and determines the format of the optical disk.

[0005]

The conventional technique has a problem in that the optical disk device requires a sensor and a circuit for detecting a mark or a hole for format discrimination, which complicates the structure of the device. The present invention has been made in view of the above conventional problems, and an object of the present invention is to provide an optical disk device capable of discriminating the format of an optical disk with a simple configuration.

[0006]

In order to solve the above problems, the present invention is directed to "an optical disk in which a track is divided into sectors and an identification mark is recorded at a predetermined position in each sector". In the optical disc device for recording or reproducing information in the sector unit, an identification mark for detecting the identification mark from the reproduction signal from the optical disc based on the detection parameter and outputting the detection signal. Detecting means, and parameter setting means for sending the detecting parameter set assuming a disk format having a predetermined number of sectors to the identifying mark detecting means,
Depending on whether or not the detection signal is output within a certain period of time,
The optical disk has a format determining means for determining whether or not the optical disk has the same disk format as the disk format.

[0007]

In the present invention, the format is discriminated by detecting the identification mark from the reproduction signal from the optical disk. The parameter setting means sets the detection parameter in the identification mark detecting means when a disk format having a predetermined number of sectors in a track is assumed. The identification mark detecting means detects the identification mark from the reproduced signal based on this detection parameter. However, if the optical disk has a format different from the expected disk format, the identification mark cannot be normally detected. Because of this,
The matte determining means can determine whether or not the optical disk being reproduced has the expected disk format, depending on the presence or absence of the detection signal from the identification mark detecting means within a certain period of time.

[0008]

FIG. 3 is a diagram showing an example of a sector format in a track of an optical disc. In the figure, SM is
It is a sector mark indicating the beginning of a sector. Following the SM, there is an ID part in which the track address and the sector address are stored. The next VFO section is a continuous repetitive data pattern for surely reproducing the data even if the disk rotation fluctuates. In the recording / reproducing apparatus, the data is reproduced by this pattern. Generates a clock for reading or writing. Following the VFO section, SY
There are NC (synchronous byte part) and DATA (data part).
A mark for synchronization is recorded in the sync byte part in order to read the data in the data part. An error correction code for performing error check and error correction at the time of reproduction is written in the data section.

FIG. 1 is a schematic block diagram showing the configuration of an optical disk device according to an embodiment of the present invention. In FIG.
The optical disc 1 is rotated by a spindle motor (not shown), and the optical head 2 is an optical beam on the recording surface of the optical disc 1.
The information is recorded or the recorded information is read by irradiating the recording medium. At the time of recording, first, a user computer to be recorded in sector units from a host computer (not shown).
Data is input to the host interface circuit 8. Then, the user data is ECC (Error Checking Correct).
ion) circuit 7 and the error correction code is added.
The user data to which the error correction code is added is input to a modulation circuit and is modulated by a modulation method such as (2-7) modulation and various marks (sector marks) corresponding to the format of FIG.
, SYNC) are added and output to the optical head 2 as a recording signal.

Next, the operation during reproduction will be described. The information read by the optical head 2 is output as a reproduction signal. This reproduction signal contains the sector mark, ID, VFO, SYNC, DATA in the format shown in FIG.
The signal corresponding to is included. The reproduced signal is input to, for example, the sector mark detection circuit 3, the SYNC detection circuit 4, and the demodulation circuit 5. The sector mark detection circuit 3 detects a sector mark indicating the beginning of a sector from the reproduced signal. Then, the detection signal is output to the CPU 6. CPU
6 is C based on the time when the sector mark is detected.
Start the timer inside PU6. After that, at the time point (a certain period) where the detection of the synchronization byte is expected, the detection permission signal is output. The SYNC detection circuit 4 detects the sync byte from the reproduction signal only while the detection permission signal is being output. This is to prevent false detection as much as possible. When the sync byte is detected while the detection permission signal is being output, the SYNC detection circuit 4
Outputs a detection signal to the CPU 6 and the demodulation circuit 5.

The demodulation circuit 5 demodulates the data and the error correction code which are input subsequently to the sync byte in the reproduction signal by the detection signal from the SYNC detection circuit 4, and the ECC
Output to the circuit 7. The ECC circuit 7 receives the demodulated data and the error correction code, performs error checking and error correction, and outputs it as user data to the host interface circuit 8. Then, the user data is sent to the host computer.

Next, the sector mark detection circuit 3 will be described. When the sector mark detection circuit 3 detects a sector mark from the reproduced signal, a parameter for detection is set. The setting of this parameter is performed by the CPU 6. As a typical example of parameters, a sector marker
There is one that regulates the period for detecting the black mark. This is based on the same concept as the detection permission signal in the SYNC detection circuit 4 described above. The period during which the sector mark detection operation is performed should not be too long in order to prevent erroneous detection of the sector mark. Therefore, the sector mark is detected and the detection signal is output only within a certain period before and after the time when the sector mark is expected to be detected.

"Time when sector mark detection is expected"
Can be determined as follows. The inside of a track is divided into a plurality of sectors, and if the capacity of each sector is equal, the spot of the optical beam irradiated on the track will pass over the sector mark at regular intervals. .. Therefore, the sector mark in the reproduced signal also appears at regular intervals. The time interval at which this sector mark appears can be known in advance because it depends on the rotation speed of the disk. If the time interval at which the sector mark appears is known, the time when the next sector mark appears can be known by counting the time based on the time when a certain sector mark is detected. Therefore, it is possible to determine "the time when the sector mark is expected to be detected".
Actually, the time interval at which the sector mark appears is slightly shifted due to the influence of uneven rotation of the disk, so that the detection is performed in a certain period before and after the expected time.

The time from the detection of a certain sector mark to the time at which the next sector mark is expected to be detected is one of the parameters to be set in the sector mark detection circuit. Is. By the way, if the format of the optical disc to be reproduced is different, the time interval in which the sector mark appears in the reproduced signal also becomes different. For example, an optical disc in which one track is divided into 512 sectors and 1024
Comparing with an optical disk divided into sectors, the number of sector marks in one track is ½ of the former one. Therefore, when the reproduced signal is read under the same condition, the time interval in which the sector mark appears in the reproduced signal is twice that of the former case.

Therefore, for example, a parameter corresponding to reproducing an optical disc in which one track is divided into 512 sectors is set in the sector mark detection circuit 3 and one track is divided into 1024 sectors. When the optical disk is reproduced, the sector mark detection signal is not output at the time when the detection of the second sector mark is expected.
Since the sector mark detection circuit 3 does not detect the sector mark detection signal, it can be recognized that the format of the optical disk is different.

FIG. 2 is a flow chart showing the format discriminating operation in the optical disc apparatus of this embodiment. The operation will be described below with reference to FIG. Here, track 1
Two formats with different number of sectors per cycle (first
And the second format) will be described. First, the parameters corresponding to the first format are set in the sector mark detection circuit 3 (step 21). Then, the CPU 6 starts the built-in timer (step 22). The sector mark detection circuit 3 starts a sector mark detection operation from the reproduction signal. In this case, as described above, the sector mark detection circuit 3
Detects the sector mark only within a fixed period at each time interval according to the set parameters. If the format of the optical disc 1 being reproduced matches the corresponding format of the parameter set in the sector mark detection circuit 3, the sector mark detection circuit 3 outputs a sector mark detection signal within a fixed time. If the formats do not match, the sector mark detection signal is not output within a fixed time. The term "constant time" used here means
For example, it refers to the time until the time point when the sector mark detection circuit 3 should perform the detection operation ends after the above "time point at which the sector mark detection is expected" has passed. It may be longer than that. The CPU 6 monitors the time with the built-in timer (step 23, timeout monitoring), and if the sector mark detection signal is input within a certain time (step 24), the format of the optical disc 1 being reproduced is
It is determined to be the first format. When the detection signal is not input within a fixed time (that is, when the time-out occurs), the parameter corresponding to the second format is set in the sector mark detection circuit 3 (step 26) and the above procedure is repeated. .. If the sector mark cannot be detected by the second parameter (determined in step 25), it is judged as an error.

In this embodiment, two different records are used.
I explained the case of distinguishing Matt optical disks,
It can also be applied to the determination of three or more different formats.
First, the parameters corresponding to the first format are set and the sector mark detection is performed.
The parameters corresponding to the first format are set, the parameters are retried, and if they cannot be detected, the parameters corresponding to the third format are used.

Further, in this embodiment, the sector mark detecting circuit is provided with a parameter indicating the time interval at which the sector mark appears.
Although the setting of parameters has been described, the parameters are not limited to this. It suffices that the setting condition when reproducing an optical disc of a certain format is different from the setting condition when reproducing another format. Furthermore, 2
It is also possible to provide two sector mark detection circuits corresponding to the reproduction of optical disks of different types of formats and switch which circuit is used for detection. In this case, the signal for switching the two sector mark detection circuits has the same function as the parameter setting.

In this embodiment, the format decision is made by detecting the sector mark, but a mark other than the sector mark may be used. In this case, it may be recorded at a predetermined position in the sector and can be clearly distinguished from other marks and data in the sector.

[0020]

As described above, according to the present invention, since the identification mark in the sector of the optical disc is detected to determine the format, it is not necessary to provide the optical disc and the disc cartridge with the mark or the hole, and the mark or the hole can be detected. There is an effect that the optical disk device does not become complicated because a sensor and a circuit for performing the operation are not required.

Further, since the identification mark detection circuit provided in the conventional optical disk device can also be used, there is an effect that the device is not complicated.

[Brief description of drawings]

FIG. 1 is a schematic block diagram showing a configuration of an optical disc device according to an embodiment of the present invention.

FIG. 2 is a flowchart showing a format determining operation in the optical disc device according to the embodiment of the present invention.

FIG. 3 is a diagram showing an example of a sector format in a track of an optical disc.

FIG. 4 is a diagram schematically showing an optical disc having a spiral track.

[Explanation of symbols]

 1 Optical Disc 2 Optical Head 3 Sector Mark Detection Circuit 6 CPU

Claims (1)

[Claims] 1. An optical disc in which information is recorded or reproduced on a sector-by-sector basis with respect to an "optical disc in which a track is divided into sector units and an identification mark is recorded at a predetermined position in the sector". In the device, there is an identification mark detecting means for detecting the identification mark from the reproduction signal from the optical disc based on the detection parameter and outputting the detection signal, and a predetermined number of sectors in the track. According to the parameter setting means for sending the detection parameter set assuming the disk format to the identification mark detecting means, and the presence or absence of the output of the detection signal within a fixed time,
An optical disk apparatus comprising: a format determining unit for determining whether or not the optical disk has the same disk format as the disk format.