JPH08190729A - Multibeam optical disk device - Google Patents

Abstract

PURPOSE: To make ID read circuits one circuit. CONSTITUTION: Information is recorded or reproduced by projecting plural light beams 8a and 8b to an optical disk, which has plural tracks formed in a concentric circular pattern or a spiral pattern on a recording surface and in which each track is divided into plural sectors each having an ID part 9 recorded with an identification number. A distance between the respective light beams 8a and 8b in the circumferential direction is made larger than a length of the longest ID part 9 in the circumferential direction.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multi-beam optical disc apparatus for recording or reproducing information on a read-only type, rewritable type, one-time writing type optical disc using a plurality of beams.

[0002]

2. Description of the Related Art Conventionally, an optical disc, which is a recording medium, has a plurality of tracks formed concentrically or spirally on the disc surface, and each track is divided into a plurality of areas called sectors. An optical disc that records or reproduces information on or from the optical disc records or reproduces information in units of the sector.

Within each sector of the optical disk, there are an ID section in which the identification number of the sector is recorded and a data section for recording user data (or data used by the user). When recording or reproducing to or from a desired sector of an optical disc, first, an ID (for example, track number or sector number) is read from the ID section in the sector, and when the ID matches the ID of the desired sector, User data is recorded in the data part of the sector (or the recorded data is read).

In the optical disk device, information is recorded on or reproduced from the optical disk by irradiating a track of the optical disk with a light beam. In order to increase the speed of recording or reproducing operation, a multi-beam optical disk device that irradiates an optical disk with two light beams has been put into practical use.

[0005]

In the conventional multi-beam optical disk device as described above, each beam is ID
Since there is a possibility that the beam may pass through the section, an ID reading circuit was required for each beam. Therefore, the present invention
It is an object of the present invention to provide a multi-beam optical disc device in which the number of reading circuits can be one.

[0006]

In order to solve the above problems, a multi-beam optical disk device of the present invention has a plurality of tracks formed concentrically or spirally on a recording surface, and each track is divided into a plurality of sectors. Then, with respect to the optical disc provided with the ID part in which the identification number is recorded in each sector,
In a multi-beam optical disc device that records or reproduces information by irradiating a plurality of light beams,
The circumferential distance of each light beam is set to be longer than the circumferential length of the longest one of the ID portions.

Further, it is preferable that the circumferential distance of each light beam is shorter than the shortest circumferential length of the sectors. Further, a configuration is provided in which there is a moving unit that moves each light beam in a direction substantially parallel to the radial direction of the optical disc, and an extension line of the moving direction of at least one beam by the moving unit does not pass through the rotation center of the optical disc. It is preferable that

[0008]

In the optical disk device of the present invention, only one ID reading circuit is required, and the cost and the circuit scale can be reduced.

[0009]

1 is a block diagram of an optical disk device according to an embodiment of the present invention. The optical disc 1 is a spindle motor 2
And is rotated by the spindle motor 2. A plurality of spiral or concentric tracks are formed on the information recording surface of the optical disc 1, and information is recorded or reproduced by irradiating the tracks with a light beam.

Two light beams (a beam 8a and a beam 8b) are emitted from the head 3. Head 2
In order to emit two beams from the head, two semiconductor lasers may be provided in the head 2, for example. The servo circuit 4 drives the actuator in the head 3 to control focusing of the beam, tracking, and rotation of the spindle motor 2. In other words, each beam is focused on the track surface by focusing control, and by tracking control,
The irradiation position of each beam should always be on the track.

The recording / reproducing circuit 6 processes the reproduced signals read by the beams 8a and 8b from the optical disk 1 and outputs the signals of the ID portion in the reproduced signals read by the respective beams to the ID reproducing circuit 7 while switching them. . In addition, control for recording data on the optical disc 1 is performed. The ID reproducing circuit 7 inputs the signal of the ID section and informs the microcontroller 5 of the track number and the like. The microcontroller 5 gives an operation instruction to the servo circuit 4 and the recording / reproducing circuit 6.

The actuator 9 connects the head 3 to the disk 1
Move in the radial direction. It is for moving the beam to a desired track on the disk 1. FIG. 2 is a diagram showing a state where the beams 1a and 2b are applied to the disk 1. The disk 1 is divided into each zone (divided into four zones A, B, C and D in FIG. 2) in the radial direction. This is a so-called zone CAV format. Each zone consists of many tracks (not shown). Each track is composed of an ID section 9 in which a track number and a sector number are recorded, and a data section 10 in which user data to be recorded or reproduced is recorded.

In this embodiment, the beam 8a and the beam 8b
Are illuminated on different tracks. Furthermore, beam 8
The beam a and the beam 8b are applied to the tracks in the same zone. As shown in FIG. 2, in the same zone, the length of the ID portion in the track direction (that is, the circumferential direction) is longer toward the outside. The circumferential distance between the beams 8a and 8b is set to be slightly longer than the length of the longest ID portion. The distances in the circumferential direction of the beams 8a and 8b are shorter than the distance from the ID section 9 in FIG. 2 to the ID section of the next sector. By arranging the two beams in this way, the two beams do not pass over the ID section at the same time.

In a zone CAV format disk, the length of each sector in the zone in the track direction is
The innermost track is the shortest, and the track is longer toward the outer track.
Therefore, as described above, the ID portion is also longer toward the outer circumference. In general, the length of the innermost sector is the same in every zone, and the length of the outermost sector is also the same in every zone. The number of sectors included in one turn of the track increases in the outer zone.

Therefore, as described above, the two beams are arranged within a certain zone at such a distance that they do not pass through the ID section at the same time, and they are kept at the same distance when they are irradiated to other zones. For example, even in the other zones, the two beams do not pass on the ID section at the same time. Therefore, in this embodiment, the moving direction of the beam 8a is set to the solid line L direction in FIG. 2, and the moving direction of the beam 8b is set to the alternate long and short dash line M direction. The two lines L and M are parallel to each other. Therefore, the beams 8a and 8b are always kept at a constant distance in the circumferential direction. When the solid line L is extended, it passes through the rotation center O of the disc 1, but the dashed line M is extended and the disc 1 is extended.
Does not pass through the rotation center O of.

The operation during recording will be described with reference to FIG. The microcontroller 5 has an actuator 9
Is driven to move the head 3 near a desired track. The head 3 irradiates the two beams 8a and 8b on different tracks on the disk 1. As the disk 1 rotates, the irradiation positions of the two beams relatively move on the track.

The respective beams are reflected on the disk 1, and the reflected light is received by the light receiving element in the head 3. A reproduction signal is obtained from this received light signal. The reproduction signal is input to the recording / reproducing circuit 6. Since there are two beams, two reproduction signals are input to the recording / reproducing circuit 6. The recording / reproducing circuit 6 detects the reproduced signal of the ID portion from the reproduced signals,
It is sent to the D reproduction circuit 7. The ID reproduction circuit 7 inputs the reproduction signal of the ID section, reads the track number and the sector number in the ID data, and sends them to the microcontroller 5. From the two reproduction signals input to the recording / reproducing circuit 6, I
The D part is not detected. Therefore, the ID detection circuit 7 only needs to have a function capable of processing one ID section. It is not necessary to be able to process more than one ID part at the same time.

The micro controller 5 inputs the track number and sector number output from the ID reproducing circuit 7 and compares them with the track number and sector number of the sector to be recorded. If they match, a recording signal is output to the recording / reproducing circuit 6. As the recording signal, a binary signal indicating the information to be recorded is sent. When the recording signal is input, the recording / reproducing circuit 6 performs control to intensity-modulate the beam 8a and the beam 8b according to the level of the recording signal. Such intensity modulation can be performed by controlling the drive currents of the respective semiconductor lasers emitting the beam 8a and the beam 8b. By modulating the intensity of the beam, information can be recorded in the data section following the ID section in the sector of the optical disc 1.

In this embodiment, information is recorded on the optical disc 1 using two beams, a beam 8a and a beam 8b.
The recording / reproducing circuit 6 alternately allocates the recording signals that are sequentially input to one of the beams and modulates each beam to record with two beams. next,
The reproducing operation will be described.

The two reproduction signals are input to the recording / reproducing circuit 6, and the recording / reproducing circuit 6 detects the reproduction signal of the ID portion from the respective reproduction signals and sends it to the ID reproducing circuit 7 as in the recording operation. Is. The ID reproduction circuit 7 receives the reproduction signal of the ID section and inputs the track number in the ID data,
The sector number is read and sent to the microcontroller 5. From the two reproduced signals input to the recording / reproducing circuit 6,
At the same time, the ID part is not detected. Therefore, I
The D detection circuit 7 only needs to have a function capable of processing one ID section. It is not necessary to be able to process more than one ID part at the same time. This point is also the same as when recording.

The microcontroller 5 inputs the track number and sector number output from the ID reproducing circuit 7 and compares them with the track number and sector number of the sector to be reproduced. If they match, the reproduction signal of the data portion next to the ID portion, which is subsequently output from the recording / reproducing circuit 6, is input. The recording / reproducing circuit 6 alternately reproduces the reproduced signals obtained from the two beams from the micro controller 5 respectively.
Output to.

[0022]

As described above, in the optical disk device of the present invention, it is not necessary to provide a plurality of ID detection circuits, and the data recording / reproducing operation with multi-beam can be performed with a small circuit scale.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of an optical disc device according to an embodiment of the present invention.

FIG. 2 is a diagram showing a beam irradiation position of an optical disc device according to an embodiment of the present invention.

[Explanation of symbols]

 1 optical disk, 2 spindle motor, 3 head, 4 servo circuit, 5 microcontroller, 6 recording / reproducing circuit, 7 ID reproducing circuit, 8a, 8b beam, 9 ID section, 10 data section.

Claims (3)

[Claims] 1. An optical disc in which a plurality of tracks are formed concentrically or spirally on a recording surface, each track is divided into a plurality of sectors, and each sector is provided with an ID section in which an identification number is recorded. On the other hand, in a multi-beam optical disk device that records or reproduces information by irradiating with a plurality of light beams, the circumferential distance of each light beam is determined from the circumferential length of the longest one of the ID portions. A multi-beam optical disc device having a long distance. 2. The multi-beam optical disk apparatus according to claim 2, wherein the circumferential distance of each light beam is shorter than the shortest circumferential length of the sectors. 3. A moving means for moving each light beam in a direction substantially parallel to a radial direction of the optical disk, wherein an extension line of the moving direction of at least one beam by the moving means defines a rotation center of the optical disk. The multi-beam optical disk device according to claim 1 or 2, wherein the multi-beam optical disk device does not pass.