JPS59188843A - Optical disk device - Google Patents

Abstract

PURPOSE:To detect an indicator in an accurate and comparatively simple way by recording a mark pattern which is digitally modulated with a lower frequency than those of the address and data areas to the indicator area. CONSTITUTION:An indicator mark area 6 where an indicator mark indicating an indicator area (a) is recorded is formed on the area (a). Then gap areas 7 and 8 having desired length are provided before and behind the area 6. Then the contents (mark) of the area 6 is decoded to decide the arrival of the area (a). The address information on the information track and sector is written in an address area (b). When an access is given to a data area (c) of the corresponding sector, the contents of the area (b) are read out and checked after detection of presence of the area (a). Then the user data is read out of and written in the area (c) after a desired sector is confirmed.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field of the Invention The present invention relates to an optical disc device, in particular an address area, an indicator area for indicating sector boundaries.
The present invention relates to an optical disc device in which a mark pattern of, for example, FM modulation or MFM modulation is recorded in a digital format at a frequency different from that of a data area, and a sector signal is reliably detected. .

(Bl Background and Problems of the Technology) Traditionally, data and information that can be detected optically using a radiation beam or a radiation beam and a magnetic field have been used.
2. Description of the Related Art Disc-shaped recording media in which recording is performed in areas and disc devices that utilize the same are known. The recording medium is configured as shown in the first section, for example. That is, on the recording medium 1, there are a plurality of information tracks 2-0.2-1.・
. . are prepared, and the information track is composed of a plurality of sectors a-1, 3-fang, . . . as shown in FIG. 1 (C1).

Each sector has an indicator area a as shown in the first section.
It consists of an address area b and a data area C. Note that the indicator area α is, so to speak, sector 3-1.3-2. It can be thought of as indicating the boundaries of ..., the above address area B records address information such as related sectors and tracks, and the above data area C records data used by the user. There is.

Figure 1 +Bl shows the information track 2- of the substrate 4 of the recording medium 1.
0.2-1. . . . shows a cut surface cut in a direction perpendicular to .

5-1... constitute each information track. That is, the information track 2-0 is placed on the track guide groove 5-0, the information track 2-1 is placed on the track guide groove 5-1, etc.
...Information is recorded by forming unevenness or bits in the direction along each track.

Although it depends on the type of recording medium 1, the data area C can generally be considered as a user writing area. However, the indicator area α and address area b can be considered to be playback-only areas, and when producing disc media,
Information is added in advance in a circumferential relief shape.

When reproducing the information from the indicator area G, address area b, and data engineering 976, the information track 2-0.2-1... is used with a laser beam.
In the direction along the track guide groove 5-0.5-1,
... using the depth of the groove while tracking the above laser.
Make the beam run. During this time, the information recorded as described above is read.

Conventionally, the structure is as described above, but the above-mentioned indicator
The area α indicates the boundary of each sector, and it is desirable to correctly detect the indicator area α so that the contents of the subsequent address area b and data area C can be reliably read.

(q) Object and Structure of the Invention The present invention aims to solve the above-mentioned problems. 1. The optical disc device of the present invention has a plurality of training tracks each divided into a plurality of sectors, and each tracker has a a data area in which optically detectable information can be recorded using a radiation beam or using a radiation beam and a magnetic field; and an address area in which address information is recorded;
A disk-shaped recording medium having at least an indicator area indicating the boundary of each sector, the indicator area and the address area having an optically detectable relief structure, Address information is recorded in the address area in a digitally encoded form similar to the data area, and the indicator area is digitally encoded at a lower frequency different from the address area and data area. the detector is configured to use a disk-shaped recording medium on which a mark pattern modulated by the formula is recorded, and includes a detector for reading information on the recording medium, an amplifier for amplifying the signal from the detector, and the amplified amplified signal. a data change point detection circuit for detecting a data change point in the recorded signal; a first timer that responds to an increase below the fundamental frequency of the recorded information in the indicator area; and 2. a second timer that does not respond to the clock and responds to the unrecorded area;
a demodulator that demodulates information from the indicator area, a pattern detector that detects the mark pattern on the indicator area, and a counter and gate circuit, and the second timer resets the counter. causing the counter to count the output of the first timer, and when the pattern detector detects the mark pattern while the count value of the first timer is within a predetermined value range, or The present invention is characterized in that the presence of the indicator area marked J is detected when the counter has counted a predetermined number of outputs of the first timer. This will be explained below with reference to the drawings.

(D) Embodiment of the Invention Figure 12 is an explanatory diagram illustrating the mode of an indicator area and the mode of indicator area detection according to an embodiment of a disk-shaped recording medium according to the present invention.

FIG. 3 shows the configuration of an embodiment of the disk device of the present invention.

In the case of the disk-shaped recording medium of the present invention, the fundamental frequency of recorded information in indicator area α is different from those in address area b and data area C, as typically shown at the bottom of the drawing. For example, it has a low frequency. By doing so, it becomes possible to detect the fundamental frequency component in the read signal and determine the arrival of the indicator area α. However, this alone is not necessarily sufficient to determine the arrival of the indicator area; in the case of the present invention, in addition, within each inch, a specific mark indicating the area α is provided. The pattern will be recorded. and.

Judgment condition by detecting the above fundamental frequency component,
The arrival of the indicator area α is determined by AND logic with the determination condition based on reading the mark pattern.

Note that in the case of the present invention, instead of adopting a configuration in which the fundamental frequency component of the information recorded in the indicator area is extracted by a filter or the like, it responds to a clock having a frequency lower than the fundamental frequency of the information recorded in the indicator area ball. A timer and a timer that responds to unrecorded areas are used.

The topmost part of FIG. 2 shows a typical manner of recording information on sectors. On indicator area a, there is an indicator indicating the indicator area.
There is at least an indicator mark area 6 for recording marks, and gap areas 7.8 of a desired length exist before and after the indicator mark area 6. Then, by decoding the contents (marks) of the indicator mark area 6.

Determine that indicator area a has arrived 1
information. In address area b.

Address information such as the information track and sector described in E is written. When accessing the contents of the data area C of the sector, the presence of the indicator area α is detected, and then the address information is written. The contents of area b are read and checked.

After confirming that it is the desired sector, user data is read/written into data area C. Data used by the user is recorded in data area C, and generally an unrecorded area 9 exists at the end of area C. This will be explained below along with the configuration shown in η-3. In FIG. 3, 10 is a photodetector that reads information from the recording medium 1, 11 is an amplifier, 12 is a data change point detection circuit, and 13 is an indicator area demodulator that reads information from the recording medium 1. 14 is a first timer according to the present invention;
5 is a second timer according to the present invention, and 16 is an indicator.
Area pattern detector, area 6 shown in Figure 2
The first timer 14, which detects the content of the information recorded in the indicator area α, responds to a clock frequency lower than the fundamental frequency of the recorded information in the indicator area Frequency) or higher
It is configured so that it does not respond to Tsuku. Further, the second timer 15 is configured to respond to the unrecorded area 9, but not to respond to other areas.

If the signal (d) from the detector 10 is as shown in FIG. 2, the signal W passing through the amplifier 11 has a waveform as shown in FIG. The data change point detection circuit 12 extracts the zero level passage point in the signal (-,
A pulse like signal (1) is generated. The demodulator 13 receives the above signal (/month).

As is conventionally known, a clock (y) and a demodulated signal (h) are output by demodulating an FM modulated signal or an MFM modulated signal.

Further, the first timer 14 detects the above-mentioned clock (g) and notifies the 1 counter and gate circuit 17 of the detected clock (g).

The counter and gate circuit 17 operates in a quadratic manner. That is, upon receiving the signal (/J) from the second timer 15, an internal counter (not shown) is reset to zero.Then, in response to the signal (j) from the first timer 14, the above The contents of the counter are incremented (see 1 counter j in Figure 2).

The counter and gate circuit 17 notifies the pattern detector 16 of a signal (&) when the contents of the counter reach the value r7J, for example. The pattern detector 16 detects the signal (
&) is at H level, the above-mentioned signal (h) is decoded. If the decoding is successful, this information is output as output A. That is, the arrival of indicator area a is notified. However, in general, noise is superimposed on the signal (a), and the mark pattern at location W cannot be deciphered from the demodulated signal (A). In this case, the above-mentioned counter in the counter and gate circuit 17 reaches a predetermined value or more, and output B is generated based on this. That is, output B notifies that the indicator area α has arrived, as judged from the counter side, although the above-mentioned output A was not output.

In this way, the detection accuracy of the indicator is significantly improved by using both the detection using the mark pattern and the gate signal (ie, output A) and the detection using only the counter (ie, output B).

In detecting the arrival of the indicator area α, when only the count results from the counter and gate circuit 17 are used, the positional accuracy of detection is inferior to a method in which determination is made using a mark pattern and a gate signal. However, even if some noise is mixed in, if the count value reaches a predetermined value, it can be detected as area α, so the detection error rate is lower than in the method of determining based on mark patterns and gate symbols. Detection by a Naori counter, that is, detection of only the frequency, is affected by the clock (Ct
) is affected in a direction that cannot be detected. For this reason, the introduction of noise affects the counter progress in the counter and gate circuit 17 to be delayed. If the length of the gap area 8 shown in FIG. 2 is determined in consideration of this, there will be no problem.

In addition, in this type of device, for example, how many sectors from the reference position on the information track the head is located is counted by a sector counter (not shown). Even if B cannot be output normally due to contamination of noise or the like, it is possible to use the output B to cause the sector counter to count correctly. Furthermore, depending on the degree of noise mixing, even if output B is used, it is possible to read the address area and subsequently write/write user data in the data area, in the same way as when output A is used.

(I) As described in detail, according to the present invention, it is possible to detect an indicator correctly and relatively easily.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram illustrating the relationship between a disk-shaped recording medium, information tracks, sectors, and each area including an indicator area, and FIG. 2 is an embodiment of an indicator area of a disk-shaped recording medium according to the present invention. FIG. 3 is an explanatory diagram illustrating the method of detecting the indicator area and the mode of detecting the indicator area, and FIG. In the figure, 1 is a recording medium, 2 is an information track, 3 is a sector,
a is the indicator area, b is the address area, C
is a data area, 6 is an indicator mark area, 9 is an unrecorded area, 10 is a detector, 12 is a data change point detection circuit, 13 is a demodulator, 14 is a first timer, 1
5 is the second glue patent applicant Fujitsu Limited

Claims (1)

Claims: A plurality of information tracks are each divided into a plurality of sectors, each sector recording optically detectable information using a radiation beam or using a radiation beam and a magnetic field. With the data area that can be done. A disk-shaped recording medium comprising at least an address area in which address information is recorded, and an indicator area for indicating the boundary of each sector, the disc-shaped recording medium having an optical area with respect to the indicator area and the address area. The indicator area has a relief structure that can be detected visually, and address information is recorded in the same digitally encoded form as the data area in the address area, and the indicator area has a relief structure that can be detected visually. A detector configured to use a disk-shaped recording medium on which a mark pattern digitally modulated at a lower frequency different from that of a data area is recorded, a detector for reading information on the recording medium, and a detector for reading information on the recording medium; an amplifier that amplifies the signal; a data change point detection circuit that detects a data change point in the amplified signal; and a timer of Fang 1 that responds to a clock that is lower than the fundamental frequency of the information recorded in the indicator area; a second timer that does not respond to the fundamental frequency clock of the recorded information in the indicator area and responds to the unrecorded area; a demodulator that demodulates the information from the indicator area; a pattern detector for detecting the mark pattern, a counter and a gate circuit; the second timer resets the counter to cause the counter to count the output of the first timer; When the pattern detector detects the mark pattern while the count value of the first timer is within a predetermined value range, or when the counter has counted a predetermined number of the first timer outputs, An optical disc device characterized in that the indicator is detected.