JPH0157430B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a disc-shaped optical recording medium.

Various types of optical discs are known in the art, including those called video discs, audio discs, and data discs. Video signals, audio signals, and data signals encoded in spiral or concentric information tracks are recorded on these optical disks as optical information such as optical transmission characteristics, reflection characteristics, and phase characteristics. The information recorded on these optical disks can be recorded by rotating the optical disk 1 with a spindle 2 at a speed of, for example, 1800 revolutions per minute, as shown in FIG. Light emitted from a light source 4 such as a laser is focused and projected onto the information track 3 by a lens 5, a half mirror 6, a reflecting mirror 7, and an objective lens 8, and the reflected light modulated by the information track 3 is projected onto the objective. lens 8
The light is collected by the reflecting mirror 7 and the half mirror 6, and then transmitted through the lens 9 and detected by the light receiving device 10, thereby being reproduced. The elements 4 to 10 are supported by a pickup 11 and are configured to be movable together in the radial direction of the optical disk 1, so as to sequentially scan the information track in the radial direction. In addition, when recording information on the optical disk 1, for example, in the optical system shown in FIG. The light source 4 emits light with stronger energy than during reproduction, and the modulator modulates this light based on the information to be recorded and directs it from the inner circumference to the outer circumference of the optical disc 1, or The information is projected from the outer circumference toward the inner circumference, forming a spiral or concentric information track on the optical disk 1.

The features of such optical discs are that information is recorded and reproduced without contact using a light beam spot, so the recording density of information is extremely high, and the desired information recorded on the optical disc can be reproduced at will. Random access is possible. For example, an optical disk with a diameter of 30 cm can record 54,000 tracks on one side, and one frame has one track.
Can record 54,000 images. In addition, approximately 20,000 document information can be recorded if the _A4 version information is band-compressed, but the amount of information for the _A4 version is ¹⁰⁶ bits [210mm x 300mm
x 8 lines/mm x 8 lines/mm x 1/5 (compression ratio)], and redundant bits such as error correction are added to this. On the other hand, the information recorded on an optical disc is limited by the amount of information on the inner circumference of the optical disc, assuming that CLV (Constant Linear Velocity) is not used. For example, if the diameter of the innermost circumference is 110 mm and the density is 1 μm/dot, recording of 0.3×10 ⁶ bits/track is possible. According to this data, the information on one _A4 size sheet is recorded over 3 to 4 tracks, and even if various conditions are met, it is generally recorded on 2 to 4 tracks.
Recorded over 4 tracks.

The following two methods can be considered as recording methods when one piece of information spans several tracks as described above.

(1) Assume the amount of input information in advance and secure the number of recording tracks to store that amount of information. for example,
It is fixed as 1 document and 4 tracks.

(2) The number of tracks is made variable length regardless of the amount of information in one document, and information is packed from the beginning.

According to the recording method (1) above, in the case of random access, since the area is a fixed length, it is easy to move the pick-up to the target position and stop it.
For example, if a flag + control field + file number is recorded during recording, the currently stopped pick-up position can be determined from the file number at that position. By calculating position file number - target position file number) x number of fixed tracks, the pickup can be easily moved to the target position using the number of tracks as a step (instead of a scale). However, in this case, if the document has a good compression ratio, there will be wasted (unrecorded) space, which will reduce the amount of recorded information and reduce efficiency.

On the other hand, according to the recording method (2) above, documents with good compression ratio can be stored in a few tracks.
Documents with poor compression ratios use more tracks, freeing up space and allowing more efficient recording. However, in this recording method, since the compression ratio differs depending on each piece of document information, there is a problem that it is difficult to determine in which position desired information is stored when performing random access.

SUMMARY OF THE INVENTION An object of the present invention is to solve the various problems mentioned above and to provide a disk-shaped optical recording medium that is suitably configured to allow easy random access and efficient recording.

The present invention provides, in a disk-shaped optical recording medium having spiral or concentric information tracks, a track address for each track, and
It is characterized by having a file number for each piece of information.

The present invention will be described in detail below with reference to the drawings.

FIG. 2 is a diagram showing the basic format of the disc-shaped optical recording medium of the present invention.
In this example, two words, an 8-bit flag field 21 and an 8-bit control field 22, are used, and various conditions are set according to the code of the control field 22, as shown in FIG. In addition, in this example, the control field 22
The 6th to 8th bits _A5 to _A7 are used for the track address, and the 1st bit _A0 is used for the 2nd to 5th bits _A1 to _A4.
Let the parity bit be.

In FIG. 3, the dummy code and shift correction code of No. 0 are signals that have no meaning as information. In other words, on an optical disk, information is recorded in a spiral or concentric pattern, but tracking is difficult at the beginning of a spiral track or at the beginning of each track when a concentric track is used. It is possible that you are not doing it correctly. Therefore, even if image information or the like is placed in this part, it cannot be read correctly, so a dummy code is recorded in this part to ensure correct tracking. Furthermore, this dummy code is inserted at other locations than at the beginning of the track as appropriate. The jitter correction code is used to adjust the rotational speed of the optical disk in relation to the speed of the recording/reproducing signal, and is inserted into the track as appropriate. Further, the information start and information end codes No. 7 and No. 6 are inserted at the start and end positions of each information such as image information, respectively.

The formats No. 1, 2, 3, and 4 in FIG. 3 will be sequentially explained below.

In the case of No. 1, as shown in FIG. 4A, a one-word track address 23 and a file number 24 are added after the two-word flag field 21 and control field 22. The 6th to 8th bits _A5 to _A7 of the control field 22 are used for track addresses as described above. The 8th bit A ₇ of the control field 22, the 1st bits b 11 and _{a 11} of the track address 23 and file number 24, respectively.
is parity bit and odd parity. This website has a truck address ≦511,
Applies when file number ≤ address 127. For example, when the track address is 500 and the file number is 100, the result will be as shown in FIG. 4B.

In the case of No. 2, as shown in Figure 5A, each
After the flag field 21 and control field 22, each consisting of a word, a one-word track address 23 and first and second file numbers 24-1, 24-2, each consisting of one word, are added. 8th bit A ₇ of control field 22, track address 23, first and second
The first bits b ₁₁ , a ₁₁ , a ₂₁ of each of the file numbers 24-1, 24-2 are parity bits, and the parity is an odd number. This format is track address ≦ 511, address 127 ＜ file number ≦
Applies to address 16383. For example, when the track address is 500 and the file number is 500, the result will be as shown in FIG. 5B.

In the case of No. 3, as shown in Figure 6A, each
After a flag field 21 and a control field 22 each consisting of a word, first and second track addresses 23-1, each consisting of one word, are provided.
File number 24 consisting of 23-2 and 1 word
Add. 8th bit _A7 of control field 22, first and second track addresses 23-
The first bits b ₁₁ , b ₂₁ , a ₁₁ of each of file numbers 1, 23-2 and file number 24 are parity bits,
Odd parity. This format applies when address 511<track address≦65535 address and file number≦511 address. For example, the track address is 65530 and the file number is 100.
When it is a street address, it will be as shown in Figure 6B.

In the case of No. 4, as shown in FIG. 7A, after the flag field 21 and control field 22 each consisting of one word, first and second track addresses 23-- each consisting of one word are provided.
1, 23-2 and the first and second file numbers 24-1, 24-2 are added. The eighth bit A ₇ of the control field 22, the first bit b ₁₁ of each of the first and second track addresses 23-1 and 23-2 and the first and second file numbers 24-1 and 24-2, b ₂₁ , a ₁₁ , and a ₂₁ are parity bits, and odd parity. This homatsuto is
Applies to the cases where address 511<track address≦65535 address, address 511<file number≦16383 address. For example, when the track address is 65530 and the file number is 16380, the result will be as shown in FIG. 7B.

FIGS. 8A and 8B show an example of the above-mentioned data arrangement, and show a case where the file number is 100 and the track address is moved from address 500 to address 501.

FIG. 9 is a block diagram showing the overall structure of an example of an optical disk device using an optical disk according to the present invention. First, a document 31 is scanned by a suitable scanning device 32 to obtain an image signal, which is digitized by an A/D converter 33, and then redundant by a redundancy compression circuit 34 by a method known in the facsimile field. After compressing the degree, the encoding circuit 35 encodes it.
This encoded information is recorded on an optical disk by an optical recording/reproducing device 36 as described in FIG. Of course, for this record, the second
A recording format as described in FIGS. 8 to 8 is used. In the case of reproduction, the information recorded on the optical disk is read by the above-mentioned optical recording/reproducing device 36, decoded by the decoding circuit 37, and then redundancy is expanded by the redundancy expansion circuit 38. An original digital signal is obtained, converted into an analog signal by a D/A converter 39, and converted into a visible image by a hard copy device 40 or a soft copy device 41 such as a cathode ray tube, if desired.

According to the disk-shaped optical recording medium of the present invention,
Since it has one track and one address, and one document and one file number, it is possible to efficiently record desired information without creating any unrecorded empty space on the optical disk. . In addition, in the case of playback, the current position of the pick-up can be confirmed by the track address and file number, just as in the case of fixed length in which the number of tracks is fixed for one document. If a number is specified, (current position track address - target track address) is calculated, and the pick-up is easily moved to the desired position by incrementing the number of tracks (instead of a scale) as in the case of the fixed length described above. Therefore, random access can be easily performed.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the structure of an example of an optical disk device, FIGS. 2 to 8 are diagrams showing the format structure of the disk-shaped optical recording medium of the present invention, and FIG. 9 is a diagram showing the structure of an optical disc device according to the present invention. 1 is a block diagram showing an example of the overall configuration of an optical disk device using a disk. FIG. 21... Flag field, 22... Control field, 23, 23-1, 23-2... Track address, 24, 24-1, 24-2... File number, 31... Original, 32... Scanning device, 33...
A/D converter, 34...redundancy compression circuit, 35...encoding circuit, 36...optical recording/reproducing device, 37...decoding circuit, 38...redundancy expansion circuit, 39...D/A
converter, 40... hard copy device, 41... soft copy device.

Claims (1)

[Scope of Claims] 1. In a disk-shaped optical recording medium having spiral or concentric information tracks, a track address for each track is provided before the redundancy-compressible information recorded on each track;
A disk-shaped optical recording medium characterized by having a file number for each piece of information.