JPH0312031A - Optical disk device - Google Patents

Abstract

PURPOSE:To prevent laser beams from being concentrated on one track and to prolong the duration when an optical disk can be used by moving a laser beam irradiating position on an optical disk in the case of the standby of reproducing. CONSTITUTION:An optical head 1 irradiates the track of the optical disk with the laser beam to reproduce optical information. At the same time, a servo circuit 7 makes the head 1 follow the desired track of the optical disk and controls the movement of the laser beam of the head 1 so that an access circuit 8 may set the laser beam of the head 1 on the track of the optical disk where desired information is recorded. An access decision circuit 9 decides whether the action of the head 1 is for reproducing the information or for the standby of reproducing and a standby circuit 10 sets the action of the head 1 in the standby state which is preparation for reproducing the information. Then, the control that the laser beams of the head 1 are made to successively follow the plural tracks of the optical disk on both sides of the track which is followed just before the standby is performed.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to an optical disc device that records and reproduces information using an optical disc. The present invention relates to an optical disc device having a function of preventing concentration.

[Conventional technology]

Optical recording systems that record information on optical discs, especially optical disc memory systems, are capable of high-density and large-capacity recording.
It has attracted attention in recent years as a large-capacity file memory because it also provides contactless and high-speed access.

This optical disk memory method is a method for recording information on an optical disk medium. In this method, a laser beam of constant intensity narrowed to a minute diameter is applied to an optical disk medium rotating at high speed for a predetermined period of time (also called pulse width) according to the desired bit length. In this method, pits are formed using the heat generated by irradiation for a certain period of time.

As this optical disk memory method, there are, for example, the following three methods. The first method is to melt or sublimate the medium using heat to create a depression, and use this depression as a focus. In the second method, a phase transition is caused by heat to create a region in which optical properties, such as refractive index and reflectance, differ from the original state, and this region is used as a pit. The third method uses heat to reduce the coercive force of the perpendicularly magnetized film aligned upward or downward in the medium, and at the same time applies a reversal magnetic field to reverse the direction of magnetization, so that the direction of magnetization is opposite to the original state. This is magneto-optical recording, in which an area is created and this area is used as a pit.

Some of these three previously proposed information recording methods have been put into practical use.

Information recorded using this method is reproduced by utilizing the fact that the optical properties of the formed pits are different from those of the surroundings.

In addition, here, the bit is just a "dent", and the "dent" causes diffraction and interference, and the "dent"
Differences in optical properties also include cases in which diffraction or interference would not occur without them.

Such bits are formed and the recorded information is reproduced by shining a laser beam onto a medium moving at high speed and detecting optical changes in the beam reflected by or transmitted through this medium. Ru. In other words, when reproducing information recorded on an optical disk, a laser beam is irradiated so as to follow concentric circles or spiral tracks formed on the optical disk, and the pits formed on the tracks of the medium are optically illuminated. Regenerate information from properties.

On the other hand, when there is no need to reproduce information, a laser beam is irradiated onto the track of the optical disk to follow it for high-speed access, and the optical disc is put into a standby state for subsequent reproduction.

[Problem to be solved by the invention]

When the above-described conventional optical disk device repeatedly irradiates an optical disk medium with a laser beam during playback or in a standby state, the number of times the optical disk medium is repeatedly played will be affected. This situation is shown in FIG.

Figure 2 shows the number of reproductions until the recorded signal output drops by 3 dB when a magneto-optical disk prepared by sputtering a TbFeCo amorphous film on a polycarbonate substrate is repeatedly irradiated with a laser beam while varying the reproduction power. This is a diagram.

As shown in FIG. 2, as the number of reproductions increases, the reproduction signal output decreases, making it impossible to obtain desired characteristics.

As described above, conventional optical disc apparatuses have the disadvantage that if the optical disc medium is repeatedly irradiated with a laser beam many times, the optical characteristics of the optical disc medium deteriorate, and eventually the information recording and reproducing characteristics deteriorate.

An object of the present invention is to eliminate such drawbacks, and to reduce the number of times a laser beam is irradiated to a specific part of an optical disk, while making the laser beam follow the track of the optical disk in a standby state for high-speed access. An object of the present invention is to provide an optical disc device whose usable period can be extended.

[Means to solve the problem]

The present invention is an optical disc device that records and reproduces information on an optical disc using a laser beam, and is characterized by having means for moving the laser beam irradiation position on the optical disc during a standby state for information reproduction. .

[Effect]

As described above, by repeatedly irradiating an optical disk with a laser beam during reproduction or in a standby state, the optical characteristics deteriorate, and eventually the information recording and reproducing characteristics deteriorate. Therefore, when there is no need to reproduce a signal, it is necessary to avoid concentrating the laser beam irradiation.

For this reason, in the present invention, by preventing the laser beam from concentrating on one trunk when the optical disc device is in a standby state, it is possible to prevent one trunk of the optical disc from deteriorating and extend the usable period of the optical disc. .

〔Example〕

Examples of the present invention will be described below.

FIG. 1 is a configuration diagram showing an embodiment of the present invention. This optical disc device includes an optical helad 1, a laser drive circuit 2, a head amplifier 3, a signal processing circuit 4, a spindle motor control circuit 5, an interface circuit 6, a servo circuit 7, an access circuit 8, and an access circuit. A determination circuit 9;
It is composed of a standby circuit 10 and a drive control circuit 11.

Such an optical disc device records information using a laser beam. Furthermore, this optical disc device has means for moving the laser beam irradiation position on the optical disc during a standby state for information reproduction. This means includes an optical head 1, a servo circuit 7, an access circuit 8, an access determination circuit 9, a standby circuit 10,
A drive control circuit 11 is provided.

In such an optical disc device, an optical head 1 irradiates a laser beam onto a track of an optical disc to reproduce optical information on the optical disc.

The laser drive circuit 2 drives the laser of the optical head 1.

The head amplifier 3 amplifies a reproduction signal of optical information from the optical head 1.

The signal processing circuit 4 converts the reproduced signal into an information code.

The spindle motor control circuit 5 controls a spindle motor that rotates the optical disk.

The interface circuit 6 exchanges information signals with an external computer.

The servo circuit 7 causes the optical head 1 to follow a desired track on the optical disc.

The access circuit 8 controls the movement of the laser beam of the optical head 1 in order to set the laser beam of the optical head 1 on a track of the optical disk in which desired information is recorded.

The access determination circuit 9 determines whether the optical head 1 operates in an information reproduction state or a standby state in preparation for information reproduction.

In order to put the optical head 1 into a standby state in preparation for information reproduction, the standby circuit 10 directs the laser beam of the optical head 1 to a plurality of tracks on both sides of the track that was being followed immediately before entering the standby state. Performs control to follow the target in sequence.

The drive control circuit 11 sends the laser beam operation information of the optical head 1 to the access determination circuit 9 in response to the request for information from the interface circuit 6, and the laser drive circuit 2. The signal processing circuit 4 exchanges control signals with the spindle motor control circuit 5.

Next, the operation of this optical disc device will be explained.

In this optical disc device, a spindle motor control circuit 5 controls a spindle motor that rotates an optical disc, and a laser drive circuit 2 drives a laser of an optical head l. An optical head 1 irradiates a laser beam onto a track of an optical disc to reproduce optical information from the optical disc. A head amplifier 3 amplifies a reproduction signal of optical information from the optical head 1, and a signal processing circuit 4 converts the reproduction signal from the head amplifier 3 into an information code. The interface circuit 6 exchanges information signals with an external computer.

At the same time, the servo circuit 7 causes the optical head 1 to follow a desired track of the optical disk, and the access circuit 8 causes the optical head 1 to follow the track of the optical disk in which desired information is recorded. control the laser beam movement.

Further, the drive control circuit 11 sends the laser beam operation information of the optical head 1 to the access determination circuit 9 in response to the request for information from the interface circuit 6, and the laser drive circuit 2. Signal processing circuit 4. It exchanges control signals with the spindle motor control circuit 5. Then, the access determination circuit 9 determines whether the operation of the optical head 1 is in the information reproduction or standby state in preparation for information reproduction, and the standby circuit 10 sets the operation of the optical head 1 in the standby state in preparation for information reproduction. Control is performed to cause one laser beam to sequentially follow a plurality of tracks on both sides of the track that was being followed immediately before entering the standby state.

In this way, according to this embodiment, it is possible to prevent irradiation of a laser beam onto one track in the standby state. In other words, in conventional optical disc devices, when there is no need to reproduce information, a laser beam is irradiated onto the tracks of the optical disc to follow it for high-speed access, and the laser beam is applied to one track in a standby state for subsequent reproduction. It emits a beam.

In contrast, in this embodiment, when there is no need to reproduce information, when a laser beam is irradiated and followed by a track on an optical disk for high-speed access, multiple laser beams are By sequentially irradiating the tracks with a laser beam, it is possible to prevent deterioration of information recording characteristics from concentrating on one track and extend the usable period of the optical disc.

〔Effect of the invention〕

As explained above, according to the present invention, by preventing the laser beam from concentrating on one track when the optical disc device is in a standby state for information reproduction, deterioration of one track of the optical disc is prevented, and the optical disc is This has the effect of extending the usable period.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram showing one embodiment of the present invention, and FIG.
Signal output is 3dB compared to the reproduction power of magneto-optical disk.
It is a figure showing the number of reproductions until it decreases. l... Optical head 2... Laser drive circuit Head amplifier signal processing circuit Spindle motor control circuit 6 ・ 7 ・ 8 ・ 9 ・ 10 ・ 11 ・

Claims (1)

[Claims] (1) An optical disc device that records and reproduces information on an optical disc using a laser beam, which is characterized by having means for moving the laser beam irradiation position on the optical disc when in a standby state for information reproduction. Device.