JPH0799593B2 - Disc-shaped information recording medium - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a disc-shaped information recording medium for optically storing digital information and the like in a recordable / reproducible form, and more particularly to an optical disc suitable for additionally recording information.

[0002]

2. Description of the Related Art In order to record / reproduce information with an optical disk device, tracking information is required in addition to the information to be recorded. That is, the information to be recorded and the tracking information must be multiplexed and recorded. In the conventional optical disc system, all information is temporarily recorded on the entire surface of the disc, and thereafter, it is used as a read-only recording device only for reading. This is an optical video disc, an audio disc, or the like (for example, JP-A-49-68703).

On the other hand, the function of writing occasional information and reading it out as needed is a basic function in a file system or the like. In order to use the optical disk device for this purpose, it is necessary to have a tracking function at the time of writing and a function of determining a predetermined writing position. With a read-only disc, since writing is sequentially performed on the entire surface of the disc, tracking and position determining functions at the time of writing are unnecessary. In addition, at the time of reproduction, tracking can be performed based on the recorded information.

Regarding the technique of recording information while tracking (following the guide groove) by using the guide groove, Japanese Patent Laid-Open Nos. 54-130102 and 54-1301 are available.
No. 03 publication etc. are available.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to use an optical disc as a recording medium, and in a system in which information is subsequently written or added thereto, tracking information and writing information are multi-recorded. An object of the present invention is to obtain an optical disc that can perform such information and can easily separate and reproduce such information.

In particular, it is an object of the present invention to provide a disc-shaped information recording medium which can easily, independently and stably obtain recording / reproducing control information in addition to tracking information and writing information.

[0007]

In order to achieve the above object, the disk-shaped information recording medium of the present invention is a disk-shaped information recording medium for irradiating a light beam to record and reproduce information.
A tracking control guide groove having a depth of ⅛ of the wavelength of the light beam is provided in a substantially concentric shape, and a plurality of guide grooves are crotch-shaped, and flat portions radially without guide grooves are arranged at equal angular intervals. It is characterized by being.

Further, in the present invention, it is preferable that a reflective film is provided on the surface and information is recorded on the reflective film. Further, it is desirable that the flat portion having no guide groove has a width within a range that does not hinder tracking control. That is, the guide groove is used for tracking, and recording / reproduction is performed by following the guide groove. At this time, if the guide groove is interrupted, the tracking control is turned off. However, if the width (period) is small, the amount of track deviation due to this is also very small, and there is practically no problem in recording / reproducing.

[0009]

The following principle is used to record / reproduce information on / from the disk medium by the optical means.

(1) Reflection of light: Reflection (rate) according to information
Change (2) light transmission: change transmission (rate) according to information (3) light interference: 1/4 of wavelength of read light according to information
A hole with the depth of is made, and the intensity of reflected light due to interference is obtained.

(4) Phase change: A depth change of 1/8 of the wavelength of the read light is made according to the information, and the phase change of the reflected light is detected.

According to the present invention, of the above principles, (4) is used for tracking information, and the guide groove having a depth of ⅛ is interrupted, and a signal is obtained from the interrupted portion, so that this signal is recorded / reproduced in various ways. Used for time control. More preferably,
The principle of (1) is used for writing information.

It is desirable that the interrupted portion of the guide groove has a width within a range that does not hinder tracking control. In addition, since the interrupted part is laid out radially in a plurality of guide grooves at equal angular intervals, even if tracking control cannot be performed at the cut part of the guide groove, it is possible to ensure a regular signal from the cut part. Can be obtained. Therefore, it is possible to stably perform the recording / reproducing control. That is, since the cut portions of the guide groove are radially arranged, the light beams do not deviate from the cut portions even if the light beam is in a tracking-off state and fluctuates in the radial direction.

The signal from the disconnecting section can be detected, for example, by using the tracking signal according to the principle of (4) above. Since this signal is regularly obtained at equal intervals according to the number of revolutions of the disk, it can be used for recording / reproducing timing control. Further, by dividing the guide groove by this cutting portion, it can be used for cueing a recording area in which information is recorded along the subsequent guide groove. Further, the quality of the medium can be inspected at a flat portion without a groove, and the inclination of the disk can be detected.

As shown in FIG. 3, the cutting portions are radially provided at equal angular intervals, and a plurality of short-term flat areas having no groove appear at the same intervals for one round of the disk of the track. . The light spot follows the guide groove 2 and records information along it.

In the present invention, the cut portion of the groove forms a plane as shown in FIG. 3, from which the maximum intensity detection signal can be obtained. Moreover, since this portion can be easily detected even during tracking off or seek (positioning operation of the head to the target track), it is an excellent method for forming a control signal.

In the present invention, the guide groove is basically formed continuously except for the cut portion, and the information is recorded along the guide groove. At this time, the guide groove also serves to prevent the recording area from unnecessarily expanding in the radial direction of the disc.

[0018]

1 shows the relationship between a disk 1 and a track 2. The tracks may be concentric or spiral.

FIG. 2 shows a part of the AO cross section of FIG. In the disk, a groove 2 having a depth of 1/8 wavelength is formed on a substrate material 1 as track information. A reflective film 3 is further attached to the groove. The substrate 1 is made of a transparent material and receives light from the side of the surface 4 to write or read information.

The light narrowed down in a dot shape is one of the track information.
When it hits a / 8 wavelength groove, the reflected light distribution becomes asymmetric due to the relative position of the groove center and the light spot. Therefore, tracking can be performed by controlling the light spot so that the reflected light has a symmetrical distribution.

On the other hand, the writing information is carried out by modulating the intensity of the light spot on the track in accordance with the writing information to partially alter or remove the reflective film 3 of FIG. 2 with a strong light spot. For reading, a weak light spot is applied and information is detected by the reflection intensity. That is, the reflection intensity is weak in the part where the reflection film is removed, and the reflection intensity is high in the part where it is not removed. According to the above-mentioned principle, the reading principle differs between the tracking information and the writing information, and the detecting (reading) means corresponding to each is used, so that the tracking and the information reading / writing can be controlled independently.

FIG. 3 shows an embodiment of the disk according to the present invention using this principle. The present invention is characterized in that the track groove 2 is not continuous, but is interrupted according to a predetermined rule as compared with the above-described principle configuration. That is, even if the track groove 2 is not continuous, it is sufficient for tracking control. Therefore, a break point 20 having a width in a range that does not hinder tracking control is provided. As a result, a signal corresponding to the breakpoint is obtained from the output of the track detector. This signal reflects a predetermined interrupting rule and the rotating condition of the disk. Therefore, the disc rotation control information can be obtained from this signal as required, and can be used as a reference for timing reproduction and a reference for a write signal.

FIG. 4 shows recording using the optical disk of the present invention.
It is a block diagram which shows an example of a reproducing | regenerating apparatus. The disk 1 formed as shown in FIG. 3 is rotated by the motor 10.
Track information on the disc is head (pickup) 4
It is optically read by 0 and is the signal on output 200. The signal 201 representing the asymmetry of the signal 200 enters the tracking control circuit 21 and the pickup driving means 22.
A drive signal in the direction of reducing asymmetry with respect to is applied, and this portion performs a tracking control function. This allows the track to be tracked accurately. Further, the signal corresponding to the on / off of the track groove is used for various controls as necessary. For example, the timing reproduction circuit 5
0 is provided as a reference signal 202. Alternatively, it is given to the rotation control circuit 100 as a signal 203 indicating the rotation state. With this configuration, the disc can be rotated at a predetermined rotation speed (not necessarily constant).

When the write signal 400 is applied from the write circuit 70 in the above-mentioned state, the head 40 irradiates the disk with a light spot modulated by the write signal, and the reflection film 3 of FIG. 2 is partially removed. Then, the writing of information is executed.

On the other hand, the reading of the report information is performed according to the above-mentioned principle (1) by applying a light spot having an intensity to the extent that the reflective film 3 is not removed from the head 40 to the recording portion. Read signal 30
0 is photoelectrically converted by the head 40 and subjected to waveform processing (for example, binarization, simultaneous signal and data separation, etc.) by the reading circuit 60. Reference numeral 80 is a signal processing unit according to the purpose of use.

[0026]

As described above, according to the present invention, the principle of reading is different between the tracking information and the writing information, the tracking and the information reading and writing can be controlled independently, and the output from the track detector is disconnected. A signal corresponding to a point can be obtained, and various signals can be used for control as necessary.

[Brief description of drawings]

FIG. 1 is a plan view showing the relationship between discs and tracks.

FIG. 2 is a sectional view showing a part of the section of FIG.

FIG. 3 is a plan view showing the configuration of an embodiment of the present invention.

FIG. 4 is a block diagram showing an example of a recording / reproducing apparatus using the optical disc of the present invention.

[Explanation of symbols]

 1 ... Disk, 2 ... Guide groove, 3 ... Reflective film, 20 ... Break point.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Fumiyuki Inose, 1-280, Higashi Koikekubo, Kokubunji, Tokyo Metropolitan Research Center, Hitachi, Ltd. (72) Takeshi Maeda 1-280, Higashi Koikekubo, Kokubunji, Tokyo Hitachi, Ltd. Central Research Laboratory (72) Inventor Seiji Yonezawa 1-280, Higashi Koikeku, Kokubunji City, Tokyo Inside Central Research Laboratory, Hitachi, Ltd. (56) References JP 51-146803 (JP, A) IEEE spectrum Vol. 16, No. 8, August, 1979, P. 26-33, "Ten billion bits a disk".

Claims (3)

[Claims] 1. A disc-shaped information recording medium for irradiating a light beam to record and reproduce information, wherein the disc-shaped information recording medium is a guide for tracking control having a depth of 1/8 of the wavelength of the light beam. A disk-shaped information recording medium, characterized in that the grooves are provided in a substantially concentric shape, and a plurality of guide grooves are crotch-shaped and radially arranged at equal angular intervals without a guide groove. 2. The disc-shaped information recording medium according to claim 1, wherein a reflective film is provided on the surface, and information is recorded on the reflective film. 3. A guide groove is provided in the flat portion without the guide groove.
When performing tracking control and recording / playback
The disk-shaped information recording medium according to claim 1 or 2, wherein the width is within a range that does not hinder recording and reproduction .