JPH07201095A - Optical disk device - Google Patents

Abstract

PURPOSE:To protect the contact surfaces of an optical disk and a magnetic head against foreign matter intruded from the outside and to prevent occurrence of recording/reproducing failure by making the magnetic head minutely float from the surface of the optical disk with a simple constitution and also providing the function to keep the space between them constant. CONSTITUTION:The magnetic head 2 is formed in a floating structure, and space between the magnetic head 2 and the optical disk 1 is kept constant through a driving mechanism which moves the magnetic head 2 up and down. By this arrangement, the generation of scratch and damage on the optical disk 1 or magnetic head 2 are reduced, even when the foreign matter is stuck on the surface of the optical disk 1 or bitten into between the optical disk 1 and the magnetic head 2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic field modulation for rewriting information by irradiating an optical disk with a light beam and applying a magnetic field modulated by a magnetic head arranged very close to the optical disk. Method optical disc apparatus, and more particularly, to a technique for automatically adjusting a gap between a magnetic head and an optical disc.

[0002]

2. Description of the Related Art Conventionally, in the case of a magnetic field modulation type small-sized optical disk device, it is indispensable to reduce power consumption because it is mainly used for portable use. for that reason,
The magnetic head generally employs a method of contacting the surface of the optical disk, and the generated magnetic field is made as low as possible to reduce the current that must be supplied to the magnetic head.

[0003]

However, in such a contact method, since the optical disk rotates while the magnetic head is in contact with the surface of the optical disk, the foreign matter entering from the outside of the optical disk device and adhering to the surface of the optical disk. Alternatively, there is a high possibility that surface foreign matter or the like that may occur in the disk manufacturing process will be caught in the contact surface between the magnetic head and the optical disk. In particular, in the case of an optical disk device used for consumer equipment, it is used as an outdoor application or an in-vehicle application,
It is assumed that foreign matter entering the device from the outside of the optical disk device is also fine and hard, such as dust, and in some cases,
It may damage the optical disk or damage the magnetic head. When the foreign matter is thus caught between the optical disk and the magnetic head, the optical disk may be vibrated or the magnetic head may flutter, resulting in defective recording / reproduction.

The present invention has been made in order to solve the above problems, and has a simple structure in which the magnetic head is slightly levitated from the surface of an optical disk and has a function of keeping a constant gap between the two. An object of the present invention is to provide an optical disk device that protects the contact surfaces of an optical disk and a magnetic head from foreign matter entering from the outside and prevents the occurrence of recording / reproducing defects.

[0005]

In order to achieve the above object, the present invention irradiates an optical disc with a light beam spot, and at the same time, applies a magnetic field modulated according to a recording signal to the optical disc to form a pattern. In the optical disk device for recording / reproducing information by forming
The magnetic head has a floating structure with respect to the surface of the optical disk, and is provided with a drive mechanism for moving up and down the magnetic head so that the distance between the magnetic head and the optical disk is kept constant.

[0006]

According to the above construction, the magnetic head is of the floating type, and the drive mechanism for moving the magnetic head up and down keeps the distance between the magnetic head and the optical disk constant. Therefore, even if foreign matter adheres to the surface of the optical disc, the magnetic head itself can be prevented from being damaged, and even if the foreign matter is caught between the optical disc and the magnetic head, the optical disc or the magnetic head is scratched or damaged. Occurrence can be reduced.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An optical disk device according to an embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is an internal block diagram of the optical disk device according to the present embodiment. This device is used for recording and reproducing information by a magnetic field modulation method.
The optical disk 1 is rotatably driven inside the apparatus by being supported by a spindle motor (not shown). A magnetic head 2 for applying an external magnetic field is provided above the optical disc 1.
Are arranged. The magnetic head 2 is supported by a magnetic head drive mechanism 3 and has a floating structure in the state of being close to the protective film surface of the optical disc 1, so that the distance between the magnetic head 2 and the optical disc 1 is kept constant. The magnetic head 2 is
A magnetic field that is excited and modulated by a magnetic driver 4 that operates according to a recording signal is applied to the optical disc 1. Also,
The magnetic head 2 moves (seeks) in the radial direction of the rotating optical disc 1 during operation of the device.

An optical pickup 5 for irradiating the film surface of the optical disc 1 with a laser beam at the time of recording / reproducing is arranged below the optical disc 1, and the optical pickup 5 is automatically adjusted for focusing and tracking. An objective lens 6 is supported on the optical pickup 5 by a lens driving mechanism 7 so as to be vertically and horizontally movable for focusing and tracking, and is automatically focused so that a constant distance from the surface of the optical disc 1 is always maintained. It In this embodiment, a known method is used for focusing servo control.

The semiconductor laser 8 in the optical pickup 5 is
Driven by the laser driver 9, emits a light beam,
The optical beam spot is irradiated onto the optical disc 1. The beam reflected by the optical disc 1 and returned is branched by the beam splitter 10 and received by the photodetector 11. The focusing error signal detection unit 12 generates a focusing error signal based on the received light signal of the photodetector 11,
The tracking error signal detector 13 also generates a tracking error signal. The focusing error signal is amplified by the servo amplifier 14, and the actuator driving unit 1
Sent to 5. The actuator drive unit 15 drives the lens drive mechanism 7 to keep the distance between the objective lens 6 and the optical disc 1 constant.

Further, in the present embodiment, the focusing error signal generated for the automatic focusing of the laser beam as described above is used to automatically keep the distance between the magnetic head 2 and the protective film surface of the optical disc 1 constant. I am trying to adjust it. That is, the focusing error signal detector 1
The focusing error signal generated in 2 passes through the servo amplifier 14 and the magnetic head actuator drive unit 1
6 and the actuator drive unit 16 operates the magnetic head drive mechanism 3. When the objective lens 6 of the optical pickup 5 moves upward, the optical disc 1 moves upward and the distance from the magnetic head 2 decreases, so that the magnetic head 2 also moves upward. There is a need. Therefore, by using the focusing error signal of the optical pickup 5 as an error signal for vertically driving the magnetic head 2, the distance between the magnetic head 2 and the optical disk 1 can be strictly controlled to be constant.

When the error signal for focusing in the optical pickup 5 is used in order to keep the distance between the magnetic head and the optical disk constant as in the above embodiment, a simple mechanism is added to the existing mechanism. Since it is good, the device can be provided at a low cost. The present invention is not limited to the configuration of the above embodiment, and various modifications are possible. For example, in order to keep the distance between the magnetic head and the optical disk constant, means for detecting the distance is provided, and based on the detection result. The magnetic head may be moved up and down.

[0012]

As described above, according to the present invention, in the magnetic field modulation type optical disk device, the magnetic head is levitated from the optical disk and kept at a constant minute interval,
The contact surface of the optical disk or the magnetic head can be protected from foreign matter such as dust entering from the outside. In addition, it is possible to prevent recording / reproduction failure due to disturbance such as vibration that occurs when foreign matter is caught. Further, by keeping the magnetic head and the optical disk at a minute distance, the current supplied to the magnetic head may be small, and low power consumption required for portable equipment can be supported. Further, if the error signal for focusing in the optical pickup is used to keep the magnetic head and the optical disc at a constant distance, the device can be realized by simply adding a simple mechanism to the conventional optical disc device, and the cost is reduced.

[Brief description of drawings]

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

[Explanation of symbols]

 1 Optical Disc 2 Magnetic Head 3 Magnetic Head Drive Mechanism 5 Optical Pickup 8 Semiconductor Laser 12 Focusing Error Signal Detection Unit 16 Magnetic Head Actuator Drive Unit

Claims (1)

[Claims] 1. An optical disk device for recording / reproducing information by irradiating an optical beam spot on the optical disk and simultaneously applying a magnetic field modulated according to a recording signal to form a pattern on the optical disk. In the above, the magnetic head has a floating structure with respect to the surface of the optical disk, and a drive mechanism for moving the magnetic head up and down so that the distance between the magnetic head and the optical disk is kept constant is provided. Optical disk device.