JPH09180376A - Optical disc, reproducing method thereof, and optical disc reproducing apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To decrease the occupation rate of an address area even if the top and reverse surfaces of the optical disk which has both the sides reproduced at the same time or in sequence are in exactly the same recording format and to sufficiently secure a user's recording area by providing the optical disk with a 1st end a 2nd address mark on the right and left side across an address data area. SOLUTION: The 1st and 2nd address marks AM and ←AM are provided on the right and left sides across the address data area 8 consisting of a track address TA, a sector address SA, and an error detection code CRC. When the address data area 8 is reproduced from the optical disk from the left to the right of the signal array of an address area 9, the left boundary position of the address data area is discriminated with the 1st address mark AM. When the address data area 8 is reproduced from the right to the left of the signal array to the contrary, the right boundary position is discriminated with the 2nd address mark ←AM.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical disc having a recording format such as a track address of the optical disc, a reproducing method for reproducing a signal from the optical disc, and an optical disc reproducing apparatus.

[0002]

2. Description of the Related Art FIG. 3A shows a conventional optical disc, and FIG. 3B shows an optical disc device. The optical disc 1 has spiral or concentric recording tracks, and is divided into a plurality of sector areas 3. Each sector area 3 is divided by the address area 2, and data for recognizing the positions of tracks and sectors is preformatted in the address area 2 in advance. Such an optical disc 1 is mounted on the optical disc device 4 to perform recording / reproduction.

In order to increase the recording capacity and the recording rate, as shown in FIG. 3B, the front surface 1A of the optical disk 1 is recorded by the optical head 5A and the back surface 1B thereof is simultaneously recorded and reproduced by the optical head 5B. It is an effective means. Thus, in order to record / reproduce data on both sides at the same time, an optical disc formatted on both sides is used, but it is preferable that both sides have exactly the same recording format in order to facilitate management in optical disc manufacturing and reduce costs. However, when the same recording format is used and simultaneous double-sided recording / reproduction is performed on the same rotation axis, the reproduction directions of the front and back address areas are exactly opposite, and there is one address area, which is modulated by phase encoding or the like. If so, the address area on either the front or back side cannot be decrypted.

In order to overcome this problem, according to the conventional technique, the first address area 6 and the first address area 6 are provided as shown in FIG.
Both of the second address regions 7 in which the signal array of the address region 6 of FIG. The following data is recorded in the address areas 6 and 7.
The address data area 8 containing the address data to be decoded is a track address TA and a sector address S.
A and an error detection code CRC. Furthermore, a preamble PR, an address mark AM for identifying a boundary position of the address data area 8 and a postamble PO are arranged at the data end position and the data end position, respectively.

The operation when recording / reproducing simultaneously on both sides of an optical disk thus formatted will be described. For example, when reproducing the front surface 1A of the optical disc 1, the
Is reproduced in the A direction (from left to right), the first address area 6 in the forward direction is reproduced, and when the back surface 1B is reproduced, the reproduction is performed in the B direction (from right to left) in FIG. The second address area 7 is reproduced. In this way, even with the same recording format on both sides, it is possible to reproduce the address areas on both the front and back sides.

[0006]

However, in the above-mentioned structure, two address areas, that is, the first address area 6 and the second address area 7, are pre-formatted on the same surface when the groove is formed on the optical disk in advance. I have to keep it. Therefore, it is necessary to secure the address area twice as large as that of the optical disk for recording / reproducing only on one side, and the data recording area that can be recorded by the user is reduced accordingly, which causes a problem that the recording capacity is reduced.

Further, as shown in FIG. 3, if the sector area is divided into four into one rotation of the optical disk, the user's recording capacity is slightly reduced, but as in the case of the optical disk for computer data storage, one rotation is several tens of times. If it is divided into one sector area, the proportion of the two address areas 6 and 7 increases accordingly, so that the user recording area is significantly reduced.

In view of the above-mentioned problems, the present invention reduces the proportion of the address area and increases the number of divided sectors in an optical disc in which both sides are simultaneously or sequentially recorded and reproduced even when the front and back sides have exactly the same recording format. The present invention also provides an optical disc capable of ensuring a sufficient recording area for a user, a reproducing method thereof, and an optical disc reproducing apparatus.

[0009]

According to the invention of claim 1 of the present application, in an optical disk having spiral or concentric tracks, a plurality of sector areas for dividing each track and each sector arranged between each sector and An address data area in which an address data signal for identifying the position of each track is recorded, first and second address marks arranged on the left and right sides of the address data area, and the first and second address marks. Identifies the left boundary position of the address data area with the first address mark when the address data area is reproduced from the optical disc in the left to right direction of the signal array, and the address data area is recorded in the optical disc in the right to left direction of the signal array. When reproducing from, it is arranged so that the right boundary position of the address data area is identified by the second address mark. It is characterized in that it has a format.

According to the invention of claim 2 of the present application, a data sequence in which the first address mark is reproduced from the left to the right of the signal array, and a data sequence in which the second address mark is reproduced from the right to the left of the signal array. The same as
The data signal of the second address mark is arranged.

The invention according to claim 3 of the present application is characterized in that both the front surface and the back surface of the optical disk are used as recording surfaces, and both surfaces are signal-arranged in the same recording format.

The invention according to claim 4 of the present application is a method for reproducing an optical disk having the format according to claim 1,
When reproducing the address data area from the optical disc in the left to right direction of the signal array, the first address mark identifies the left boundary position of the address data area, and the address data area is reproduced from the optical disc in the right to left direction of the signal array. In this case, the right boundary position of the address data area is identified by the second address mark, and one address data area is reproduced from both left to right and right to left directions.

According to a fifth aspect of the present invention, there is provided an optical disc reproducing apparatus having the format according to the first aspect,
When reproducing the address data area from the optical disc in the left to right direction of the signal array, the first address mark detecting means for detecting the first address mark and identifying the left boundary position of the address data area, and from the right of the signal array When reproducing the address data area from the optical disk in the left direction, the second address mark detecting means for detecting the second address mark to identify the right boundary position of the address data area, and the first or second address mark detecting means. Address data decoding means for starting the decoding of the address data recorded in the address data area at the timing, and address data decoding direction for reversing the decoding direction of the address data by temporarily storing the address data in the memory according to the reproduction direction of the signal arrangement. And an inverting means. .

According to the present invention, with the above-described structure, even if the front surface and the back surface have the same recording format on both sides of the optical disk for simultaneous or sequential recording / reproduction, the ratio of the address area is reduced and the number of divided sectors is increased. A recording format of an optical disc, a reproducing method of the optical disc, and an optical disc reproducing apparatus capable of sufficiently securing a recording area for a user.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below.
This will be described with reference to the drawings. FIG. 1 shows a recording format of an optical disc according to an embodiment of the present invention. FIG.
1 (a) to 1 (d) describe the data array on the front surface of the optical disk and the operation timing, and FIGS. 1 (e) to 1 (h) describe the data array on the back surface of the optical disk and the operation timing.

FIGS. 1A and 1E illustrate the data arrangement of the address area 9 for identifying the position of each sector provided between the sectors when each track of the optical disk is divided into a plurality of sectors. It is a figure, (a) is the surface of an optical disk, (e) is the back surface of an optical disk. Or (a)
May be the back surface and (e) may be the front surface. In any case, it is important that (a) and (e) have the same recording format on the front surface and the back surface of the optical disk.

The address area 9 is composed of the following data array. The track address TA is the only address assigned to each track on the circumference formed on the optical disk. The sector address SA is an address indicating the position of each sector area obtained by dividing each track into a plurality of sections. The error detection code CRC is a code string for calculating a read error calculated from a generator polynomial defined from the track address TA and the sector address SA.

Further, the preambles PR arranged at the leading end and the trailing end of the address area 9 are for reducing the influence of the disturbance of the signal amplitude or the like caused by the low pass characteristic of the signal reproducing circuit.

The first address mark AM arranged in the front part of the address area 9 is for identifying the left end signal bit position of the track address TA which is the left boundary of the data area. Address S
In A, a unique code that rarely occurs is assigned. In FIG. 1A, the left end signal bit position of the track address TA can be correctly identified only when the front address mark AM is demodulated from left to right (direction of arrow A) toward the paper surface.

On the other hand, the second address mark ← AM arranged in the rear part of the address area 9 is for identifying the right end signal bit position of the error detection code CRC which is the data right boundary area. In FIG. 1E, the second address mark ← A from the right to the left (the direction of the arrow B) toward the paper surface.
Only when M is demodulated, the right end signal bit position of the error detection code CRC can be correctly identified.

Here, the first address mark AM and the second address mark AM
The relationship of the address mark ← AM data series will be described. The first address mark AM (for example, binary 101
111) is reproduced from left to right of the signal array (101111) and the second address mark ← AM
The data signals of the address marks are arranged so that the data sequence (101111) obtained by reproducing (for example, 111101) from the right to the left of the signal arrangement is the same. This simplifies the structure of the optical disk reproducing device, as will be described later.

As the recording modulation code of the address area 9 configured as described above, a modulation code such as phase encoding which has been generally used in the past is used. The optical disc is pre-formatted by cutting and resin molding in advance.

Since the recording formats of the address areas on the front surface and the back surface of the optical disk are exactly the same as described with reference to FIGS. 1A and 1E, it is possible to simply format the optical disks molded by the above-mentioned method without changing the format. It is possible to easily realize a double-sided recording / reproducing optical disk with good quality.

The reproducing method of the address area 9 and the structure and operation of the optical disk reproducing apparatus in the thus constructed double-sided optical disk will be described below. FIG. 2 is a block diagram for explaining the structure of an optical disk reproducing apparatus for reproducing the address areas 9 on both sides of the optical disk. In this figure, the optical disk 1 is mounted on an optical disk device 4 and rotated, and the data is read. Optical heads 5A and 5B are provided on both sides of the optical disk as shown in the figure. The outputs of the optical heads 5A and 5B are guided to the binarization circuit 11A via the preamplifier 10A, and the outputs thereof are given to the address mark detection circuit 12A. Address mark detection circuit 12A
Detects the address mark AM or ← AM, and its output is input to the address demodulation circuit 13A.
The address demodulation circuit 13A uses TA, SA, and
The CRC is decoded, and its output is output to the CRC calculation circuit 14A. CRC arithmetic circuit 14A is CRC
It is to determine whether the result of the check is normal,
If it is normal, it is output to the recording gate generation circuit 16A. The recording gate generation circuit 16A is a CRC calculation circuit 14A.
After that, the recording gate signal is generated. The reproducing circuit on the optical head 5B side is also connected to the recording gate generating circuit 16B from the preamplifier 10B having the same structure. An address mark detection circuit 12B is provided on the optical head 5B side.
A decoding direction inversion circuit 18B is provided on the output side of the. The decoding direction inverting circuit 18B is a circuit for inverting the decoding direction of the address mark, and is composed of, for example, a shift register. Other configurations are the same as those on the optical head 5A side.

Next, FIGS. 1 (b) to 1 (d) and FIG. 1 (f)
The operation of this embodiment will be described with reference to the operation timing charts from (h) to (h). However, in (b) to (d), the time axis is positive to the right, and in (f) to (h), the time axis is positive to the left. The optical disc 1 formatted as shown in FIGS. 1A and 1E is mounted on the optical disc device 4, and the address area 9 is reproduced. In order to realize double-sided simultaneous reproduction, the front surface 1A of the optical disk is reproduced by the optical head 5A and the rear surface 1B of the optical disk is reproduced by the optical head 5B. The address area 9 on the surface reproduced by the optical head 5A is amplified by the preamplifier 10A and converted into a digital signal by the binarizing circuit 11.

Next, the address mark detection circuit 12A detects the pattern of the first address mark AM, and the track address TA which is the left boundary of the address data area 8.
Identifies the leftmost signal bit position of the.

In FIG. 1A, the address mark AM is
The track address TA and the sector address SA are assigned unique codes that rarely occur, and the correct track address is obtained only when the front address mark AM is demodulated from left to right (A arrow direction) toward the paper surface. The leftmost signal bit position of TA can be identified.

FIG. 1B shows an address mark detection circuit 1
The detection output signal detected by 2A is a gate signal that accurately represents the timing of the address data area 8. The address mark detection circuit 12A is composed of, for example, a serial-parallel converter and a digital signal comparator. The binarized address signal is input to the serial-parallel converter, and always operates to detect a match between the code length data of the address mark AM and the unique code pattern of the address mark.

The detection output signal rises when the pattern matches the address mark AM as shown in FIG. 1B, and falls after the time corresponding to the data length of the address data area 8 has elapsed.

The output of the address mark detection circuit 12 is input to the address decoding circuit 13A as a demodulation start / end signal, and the address signal modulated by phase encoding or the like is demodulated and converted into a binary signal. The demodulated address signal is input to the CRC arithmetic circuit 14A and divided by the demodulated error detection code CRC of the demodulated track address TA and sector address SA. If the remainder of the division is 0, the address signal has been correctly demodulated,
The pulse 15 of the CRCOK signal is output from the output of the CRC calculation circuit 14 as shown in FIG. On the other hand, if a remainder is generated as a result of calculation, it is a demodulation error and the pulse 15 of the CRCOK signal is not generated.

Next, the pulse 15 of the CRCOK signal is input to the recording gate generation circuit 16A. The recording gate generation circuit 16A outputs the recording gate signal after a predetermined delay time DL from the pulse 15 of the CRCOK signal, and the user data 1
Record 7. As described above, the user data is recorded with a certain delay time DL provided so that the user data does not overlap the address area 9 and is not recorded.

Also, when reproducing already recorded user data, similarly, a reproduction gate signal is generated after a certain delay time DL from the pulse 15 of the CRCOK signal to define the read timing.

Next, as shown in FIG. 1 reproduced by the optical head 5B.
A signal processing method of the address area 9 on the back surface of (e) will be described. The components necessary for the reproduction signal processing on the back side are the same as those on the front side except for the decoding direction inversion circuit 18. That is, the address area 9 on the back surface is amplified by the preamplifier 10B,
The digitization circuit 11B converts the digital signal.

Next, in the address mark detection circuit 12B, the second
The pattern of the address mark ← AM is detected, and the right end signal bit position of the error detection code CRC which is the right boundary of the address data area 8 is identified. Address mark ← AM
Assigns a unique code that is rarely generated at the track address TA and the sector address SA.

As described above, the data sequence in which the first address mark AM is reproduced from left to right of the signal array and the second address mark ← AM is reproduced from right to left of the signal array. By arranging the data signals of the address marks so that they are in the same series, the address mark detection circuit 12B can have the same structure as the address mark detection circuit 12A on the front surface.

That is, as shown in FIG. 1E, the error detection code CR is correctly obtained only when the second address mark ← AM is demodulated from the right to the left (the direction of the arrow B) toward the paper surface.
The rightmost signal bit position of C can be identified.

FIG. 1F shows an address mark detection circuit 1
The detection output signal detected in 2B is a gate signal that accurately represents the timing of the address data area 8. Like the surface, it operates to detect a match with the unique code pattern of the address mark. This detection output signal rises when the pattern matches the address mark ← AM as shown in FIG. 1F, and falls after the time corresponding to the data length of the address data area 8 has elapsed.

Next, since the address data area 8 is the same data series as the surface, when reproduced from the direction of the arrow B, the data is sequentially input from the right end of the error detection code CRC as described above. That is, the data input direction is completely opposite to the surface. Therefore, the address decoding circuit 13B
Is required to have the same structure as the surface, the decoding direction inversion circuit 18 is required. The decoding direction inversion circuit 18 is composed of, for example, a shift register or the like. When the data sequence is sequentially input to this shift register from the right end of the error detection code CRC and the input for the code length of the address data area 8 is completed, this time, the shift direction of the shift register is reversed and the track address TA is read from the left end. Output it. In this way, the data is converted in the same input direction as the front side, and the address decoding circuit 13B having the same structure as the front side can be used.

The address decoding circuit 13B inputs the output of the address mark detection circuit 12B as a demodulation start / end signal, and demodulates and converts the address signal modulated by phase encoding or the like into a binary signal. The demodulated address signal is input to the CRC calculation circuit 14B as in the case of the front surface, and the demodulated track address TA and sector address SA are divided by the demodulated error detection code CRC.
If the remainder of the division result is 0, the address signal has been correctly demodulated, and the CRC operation circuit 14B outputs the CRCO signal.
The pulse 15B of the K signal is output as shown in FIG.
On the other hand, if a remainder is generated as a result of calculation, it is a demodulation error.
The pulse 15B of the CRCOK signal is not generated.

Next, the pulse 15B of the CRCOK signal is
It is input to the recording gate generation circuit 16B. The recording gate generation circuit 16B outputs a recording gate signal after a certain delay time DL 'from the pulse 15 of the CRCOK signal, and records the user data 17. In this way, the user data is recorded with a gap of a constant delay time DL ′ so as not to be recorded overlapping the address area 9.

As described above, according to the embodiment of the present invention, in an optical disc for simultaneous double-sided or sequential recording / reproduction, even if the front surface and the back surface have exactly the same recording format, the ratio of the address area is reduced, and the data recording optical disk for computer. As described above, it is possible to realize an optical disc recording format, an optical disc reproducing method, and an optical disc reproducing apparatus capable of sufficiently securing a recording area for a user even if the number of divided sectors increases.

[0042]

As described above, the claims 1 and 2 of the present application are described.
In the invention described above, by using the first and second address marks provided on the optical disc, the address can be detected regardless of the direction in which the optical disc rotates. Further, the optical disk according to claim 3 is an optical disk which records and reproduces simultaneously on both sides or sequentially, and even if the front surface and the back surface have exactly the same recording format, the proportion occupied by the address area is made small, and like the data recording optical disk for computers, Even if the number of sectors dividing one track increases, a sufficient recording area for the user can be secured. In this way, it is possible to realize an optical disc for double-sided recording / reproduction having a high format efficiency, an optical disc reproducing method, and an optical disc reproducing device with a simple configuration.

[Brief description of the drawings]

FIG. 1 is a diagram showing a recording format of an optical disc according to an embodiment of the present invention.

FIG. 2 is a configuration diagram of an optical disk reproducing device according to an embodiment of the present invention.

FIG. 3 is a diagram illustrating a recording format of a conventional optical disc and an optical disc device.

FIG. 4 is a diagram illustrating a recording format of a conventional address area.

[Explanation of symbols]

 1 optical disk 3 sector area 5A, 5B optical head 8 address data area 9 address area 10A, 10B preamplifier 11A, 11B binarization circuit 12A, 12B address mark detection circuit 13A, 13B address decoding circuit 14A, 14B CRC arithmetic circuit 16A, 16B Recording gate generation circuit 18B Decoding direction inversion circuit TA Track address SA Sector address AM Address mark

Claims (5)

[Claims] 1. An optical disk having spiral or concentric tracks, on which a plurality of sector areas dividing each track and an address data signal arranged between the sectors and for identifying the position of each sector and each track are recorded. Address data area and the first and second address data areas arranged on both sides of the address data area.
And a second address mark, and the first and second address marks are the first address mark and the left boundary position of the address data region when reproducing the address data region from the optical disc in the left to right direction of the signal arrangement. And when the address data area is reproduced from the optical disc from the right side to the left side of the signal array,
An optical disc having a format in which the right boundary position of the address data area is identified by the address mark of. 2. A data sequence in which the first address mark is reproduced from left to right in the signal array and a data sequence in which the second address mark is reproduced from right to left in the signal array are the same. 2. The optical disc according to claim 1, wherein the data signals of the first and second address marks are arranged. 3. The optical disk according to claim 1, wherein both surfaces of the front surface and the back surface of the optical disk are recording surfaces, and both surfaces are signal-arranged in the same recording format. 4. A method of reproducing an optical disk having the format according to claim 1, wherein when reproducing the address data area from the optical disk in the left-to-right direction of the signal array, the first address mark is used for the left part of the address data area. When the boundary position is identified and the address data area is reproduced from the right side to the left side of the signal array from the optical disk, the right boundary position of the address data area is identified by the second address mark, and one address data area is moved from left to right. A method for reproducing an optical disc, characterized in that the reproduction is performed from both the right and left directions. 5. A reproducing apparatus for an optical disc having the format according to claim 1, wherein when reproducing the address data area from the optical disc in the left to right direction of the signal arrangement, the first address mark is detected to detect the address data area. A first address mark detecting means for identifying a left boundary position, and a second address mark is detected when the address data area is reproduced from the optical disc in the right to left direction of the signal arrangement to detect the right boundary position of the address data area. Second address mark detecting means for identifying, address data decoding means for starting decoding of the address data recorded in the address data area at the first or second address mark detecting timing, and an address according to the reproduction direction of the signal array Decoding address data by temporarily storing the data in memory Optical disk reproducing apparatus characterized by comprising an address data decoding direction reversing means for reversing the direction.