JPH01204272A - Recording method for compact optical disk - Google Patents

Abstract

PURPOSE:To enlarge the total quantity of information which can be recorded on a disk by allowing the frequency of servo byte information to be constant and setting the recording frequency of a data byte so as to be higher in the outer periphery than in the inner periphery. CONSTITUTION:A servo byte 10 concerning a servo is radially engraved in advance and the disk is divided into three areas (an inner periphery 11, a medium periphery 12 and an outer periphery 13) in a radius direction. Sector byte information necessary for the servo is recorded with a same channel bit length concerning the whole surface of the disk and on the other hand, the channel bit length of the data byte, used for the recording and reproducing of information is speedily engraved in the inner periphery and slowly engraved in the outer periphery. Thus, while the feature of a sampled servo format is made useful, recording can be executed almost over the whole surface with usable maximum recording density from a recording and reproducing principle. Then, recording capacity, which can be used by a user, can be made large.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a recording method for recording signals on an optical disc.

[Summary of the invention] Constant rotational speed (CAV) by sampled format
When recording signals on an optical disk that rotates at This is set higher than the inner circumference, increasing the total amount of information that can be recorded on the disc.

[Prior Art] An optical recording system using a sampled format, which expresses information regarding a track position not by a continuous groove but by discretely provided bits, is attracting attention because of its many features.

I won't go into detailed explanation, but one track is, for example, 3 tracks.
It is made up of 2 sectors, and one sector is made up of 43 segments. The number of sectors to be recorded on one track is a matter of design freedom, but an example of 32 is given here to show the approximate size.

One segment consists of 18 bytes, and the 18 bytes are 2 servo bytes and 16 bytes of data pie.
Consists of. One byte consists of 15 channel bits (referred to as 4/15 modulation), and we will proceed with the discussion assuming that these channel bits have the same meaning as the basic clock.

The feature of Sampled Format 1 is that it can continuously retrieve tally information from the disk even when the optical head is moving across the track at high speed, and it can also retrieve information such as addresses and other information necessary for track tracking, that is, head movement and positioning. can be read.

In this case, the azimuth angle of the part where the servo bite is recorded is the same on the same radius both on the inner and outer circumference)
things are necessary.

FIG. 3 is a diagram showing a disc recorded using a conventional method.

The servo bits 31 related to the servo are thus carved in advance in a radial manner. These radial lines represent servo bites, and in this example there are 14,176 lines, but only a few of them are drawn schematically to simplify the diagram.

In this method, as long as the servo byte can be read, the optical head can freely access the target track.

FIG. 5 is a diagram schematically showing the planar arrangement of one segment of a conventional optical disc. The black colored bits represent the bits 1-1 which constitute the servo byte 51, and the white ones represent the bits which constitute the data byte 52.

The channel bits (spatial length) of the servo bytes and data bytes are longer at the outer periphery by the same proportion.

Note that this diagram is extremely schematic for explanation purposes, and one segment is not made up of a small number of bits as shown in the diagram.

FIG. 4 is a diagram showing a disc recorded using another conventional method, in which the disc has three areas in the radial direction (inner circumference 41, middle circumference 42
, outer circumference 43). Since the circumferential speed of the outer track is faster, signals are recorded at a higher speed.

The tallock frequency of the channel bits has a different length in each area, and within each area, the channel bits of the servo bytes and the channel bits of the data bytes recorded by the user have the same length. As a result, the number of sectors recorded on one track is naturally large in the outer circumferential region having a long circumference, and in this case, the total recording capacity increases compared to the previous embodiment. Again, with CAV, when the head moves between regions, the PLL oscillator, which is synchronized using the channel bits coming from the signal, has to resynchronize to a different frequency, so the time it takes to resynchronize. , it becomes impossible to obtain information used for tracking, and stable high-speed movement becomes impossible, which in turn becomes an obstacle to shortening inter-track access time.

Alternatively, instead of CAV, there is a method of keeping the frequency constant for each region and changing the rotation speed, but in this case, the circuit becomes simpler, but it takes time for the rotation to become stable, so The access time between tracks becomes very long when moving over the track.

[Problems and Objects to be Solved by the Invention] In the conventional method, the recording bit interval becomes longer on the outer circumference and becomes smaller on the inner circumference. Therefore, the minimum recording bit interval is dominated by the inner circumference, and in order to record the same amount of information over a long circumference (even though the density can be further reduced on the outer circumference), it is necessary to record at long intervals.

That is, if recording was performed at the shortest bit interval technically possible anywhere on the disk surface, regardless of the radius, the recording capacity could be increased even more.

The present invention aims to achieve the above object while taking advantage of the unique advantages of sample servo.

[Means for solving the problem] In an optical recording/reproducing disk using the sampled format method, sector byte information necessary for servo is recorded with the same channel bit length over the entire surface of the disk,
On the other hand, an optical disc recording method is characterized in that the channel bit length of data bytes used for recording and reproducing information is written quickly on the inner circumference and slowly on the outer circumference.

[Example] FIG. 1 is a diagram showing a disc recorded by the method according to the present invention.

A servo cutting tool 10 for the servo is radially carved in advance as shown in this figure. The disk is divided into three regions (inner circumference 11, middle circumference 12, and outer circumference 13) in the radial direction. This situation is the same as in the conventional example.

FIG. 2 is a diagram schematically showing the planar arrangement of one segment of the optical disc according to the present invention. The black colored bits represent the bits that constitute the servo byte 21, and the white ones represent the bits that constitute the data byte 22.

The channel bit length (longer spatial length) of a data byte is within
The outer circumference is about the same, but the outer circumference of the servo bit is longer.

Compared to the conventional example shown in Fig. 5, regarding the servo bite,
Although the inner and outer circumferences are the same, the density of data bytes on the outer circumference is higher than in the conventional example.

The channel bit length of the servo byte on the outer periphery is the same as the conventional example, but the channel bit length of the data pie 1~ is small.In other words, the recording density of the data byte on the outer periphery is smaller than that of the conventional example. expensive.

As a result, on the outer circumference, compared to the inner circumference: The number of servo bytes included in one segment is the same, but the number of segments included in one sector, which can increase the number of data bytes, is smaller (the capacity per sector is constant). ) This means that the number of sectors per track is large.

Naturally, the circumference of the track changes continuously depending on the radius, so dividing it into a finite number of areas like this
It may happen that a segment does not end with exactly an integer number of channel bits, which can be adjusted by the time between the last channel bit of a data byte and the first channel bit of the next sector byte.

FIG. 6 is a diagram schematically showing the temporal arrangement of one segment recorded by the method of the present invention.

In this case, for easier explanation, the horizontal axis is the time axis. Since the time allocated to each segment 1~ is the same in all areas, the servo bytes are arranged radially as shown in FIG.

Therefore, on the outer periphery recorded with a short channel bit length,
The number of data bytes that can fit into a single segment can be increased (shown as "white space" with no bits in the figure).

Note that although the explanation was given here assuming that there are three areas to be divided,
If the number is further increased, the recording surface can be used more efficiently.

Also, the number of segments that make up one sector is determined by the servo performance and rotation speed, and the values listed above are just examples.

Section 7 is an example of a signal processing circuit of a drive device for recording and reproducing data using the disc of the embodiment shown in FIG.

71 is a preamplifier, 72 is a PLL-controlled master clock generator, 73 is a frequency divider, 74 is another frequency divider, and 75 is yet another frequency divider.

A switch 77 detects where the head is located in the three regions and selects which frequency divider the clock signal is to be used by the data detector.

There is an integer multiple relationship between the length of channel bits for each region.

The data detector 79 operates using different signals as clocks depending on which area the currently captured signal comes from, or whether it is a servo byte or a data byte.

Note that this circuit configuration is just one example, and many other circuit configurations for handling the disk according to the present invention are conceivable.

〔Effect of the invention〕

According to the present invention, information regarding the servo can be continuously captured even while moving between tracks, and the oscillator of the drive system continues to oscillate in synchronization with the disk signal.
While taking advantage of the characteristics of the sampled servo format, yKF! ! Since recording can be performed over almost the entire surface at the highest practical recording density, it has the advantage of increasing the recording capacity that can be used by the user while maintaining fast track-to-track access.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing a disc recorded using the method of the present invention. FIG. 2 is a diagram schematically showing the planar arrangement of one segment recorded by the method of the present invention. FIG. 3 is a diagram showing a disc recorded using another conventional method. FIG. 4 is a diagram showing a disc recorded using another conventional method. FIG. 5 is a diagram schematically showing the planar arrangement of one segment recorded by the conventional method. FIG. 6 shows one segment 1 recorded by the method of the present invention.
The figure which schematically showed the temporal arrangement of -. FIG. 7 is an example of a signal processing circuit of a drive device that records and reproduces information using the disc of the embodiment shown in FIG. 10 Servo bite 11 Inner circumference 12 Middle circumference 13 Outer circumference 21 Servo bite 22 Data pie 1-41 Inner circumference 42 Middle circumference 43 Outer circumference 51 Servo byte 52 Data byte 71 Preamplifier 72 Master clock generator 73 Frequency divider 74 Another frequency divider 75 Yet another frequency divider 76 Yet another frequency divider 77 CPU 78 Switch 79 Data detector above FIG.

Claims (1)

[Claims] In an optical recording/reproducing disk using the sampled format method, the servo bytes required for tracking servo are recorded at the same angular frequency over the entire surface of the disk, while the recording angular frequency of the data bytes used for recording/reproducing by the user is recorded at the same angular frequency on the inner circumference. An optical disc recording method characterized by low markings and high markings on the outer periphery.