JPH07169131A - Optical disk device - Google Patents

Abstract

PURPOSE:To provide an optical disk device which employs a contacting magnetic head which has a protective function to reduce the chances of making scratches on the surfaces of an optical disk or a magnetic field head with a simple constitution and guarantees highly stable recording/reproducing operation even though there exist scratches on these surfaces. CONSTITUTION:By using a low dynamic friction coefficient material for a member 5 of the contacting surface between an optical disk 2 and a protective guide 4 placed in front of a magnetic head 3, the chances of making scratches to the surface of the disk and the contacting surface of the head are reduced. Moreover, even though a foreign object is sticking to the surface of the disk, stable recording/reproducing operations are realized.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a magnetic field for erasing and recording information by irradiating an optical disk with a light beam and applying a modulated magnetic field to the optical disk by bringing a magnetic head into contact with or in close proximity to the optical disk. The present invention relates to a modulation type optical disk device, and more particularly to protection of a magnetic head and an optical disk and improvement of stability of recording / reproducing operation.

[0002]

2. Description of the Related Art Among magnetic field modulation type optical disc devices, small ones are often used mainly for portable use, and it is essential to reduce power consumption. For this reason, most magnetic heads are of a type that is in contact with the surface of the optical disk (including those in a state of being extremely close). In this contact method, the optical disk rotates while the magnetic head is in contact with the surface of the optical disk, so that foreign matter that has entered from the outside of the optical disk device and adhered to the surface of the optical disk or foreign matter generated on the surface of the optical disk during the manufacturing process of the disk, There is a high possibility that the contact surface between the magnetic head and the optical disk will be caught. In particular, in the case of an optical disk device used for consumer equipment, it is assumed that it is used outdoors or on-vehicle, and foreign matter that enters the device is fine and hard such as dust.

[0003]

The foreign matter or the like that has entered from the outside of the optical disk device and adhered to the surface of the optical disk as described above is caught between the optical disk and the magnetic head, causing scratches on the optical disk surface or the magnetic head surface. Probability is high. When the surface of the optical disc is scratched, the scratch may come into contact with the magnetic head at the time of recording, and the optical disc may be suddenly vibrated, resulting in tracking error and recording failure. In addition, if the contact surface of the magnetic head is scratched, it is highly likely that the surface of the new optical disk is also scratched, causing the same tracking failure.

The present invention solves the above-mentioned problems and has a protection function for reducing scratches on the surface of an optical disk or the surface of a magnetic field head with a simple structure.
It is an object of the present invention to provide an optical disc device which can maintain high stability of a reproducing operation and can assure high stability of a recording / reproducing operation even if the surface thereof is scratched.

[0005]

In order to achieve the above object, the present invention provides an optical head for irradiating an optical disc with a light beam spot, and a magnetic head for applying a modulated magnetic field in a state of being in contact with or in proximity to the optical disc. An optical disc apparatus comprising: a pattern formed on the optical disc by the action of the light beam spot and a magnetic field to record information; and the recorded information is reproduced by reading the pattern. The magnetic heads are in contact with or in close proximity to each other, and are damaged when foreign matter is caught between the magnetic head and the optical disk at the front of the magnetic head with respect to the rotation direction of the optical disk. A protection guide for preventing the above-mentioned problem is provided, and as a member of a contact surface of the protection guide with the optical disk, the contact surface member and the Mutual dynamic friction coefficient of the protective film material of the disk is obtained using the material in a small relationship.

[0006]

According to the above construction, in the optical disk device employing the contact type magnetic head, the materials of the contact surfaces of the magnetic head and the optical disk can be optimized with respect to the coefficient of dynamic friction, and Even if foreign matter is attached or there is a protrusion, the optical disc is less likely to be suddenly vibrated during the recording / reproducing operation, and the scratches on the optical disc surface and the magnetic head contact surface are reduced. / The playback operation is stable.

[0007]

DETAILED 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 a plan view of an optical disk device 1 according to this embodiment, and FIG. 2 is a side sectional view of a magnetic head portion of the optical disk device according to this embodiment. The device 1 is a small portable device used for recording and reproduction. Inside the apparatus 1, the optical disk 2 is rotatably driven in the direction of arrow A by being supported by a spindle motor (not shown). A magnetic head 3 for applying a modulated external magnetic field to the recording portion of the optical disk 2 is arranged on the upper surface side of the optical disk 2. The magnetic head 3 is supported by a magnetic head support arm 3a, and when the apparatus is in operation, the magnetic head 3 is in contact with the protective film surface 2a of the rotating optical disk 2 by the head feeding mechanism 6 in the radial direction of the optical disk 2 (arrow B direction).
Seek to.

On the lower surface side of the optical disk 2, an optical head 7 for spot-irradiating a light beam onto the optical disk 2 is supported by a support arm 7a at a position corresponding to the magnetic head 3 with the optical disk 2 interposed therebetween. Optical head 7
Are operated integrally with the magnetic head 3. The operation of recording information on the optical disk 2 is performed by the magnetic head 3
Is performed by irradiating a light beam spot by the optical head 7 in a state where a magnetic field is applied. Further, the reproducing operation of the information recorded in this way can be performed by detecting the reflected light of the light beam spot irradiation by the optical head 7. In addition,
In the optical disc 2 of FIG. 2, 2b is a disc substrate, 2
Reference numeral c is a recording film portion, and 2d is a reflective film.

On the other hand, when the protective film surface 2a of the optical disk 2 is attached with a minute foreign substance such as sand dust that has entered from the outside of the apparatus 1 or there is a minute protrusion generated during the manufacturing process, the magnetic head 3 and It gets caught in the contact part with the protective film surface,
It will hurt each one. Therefore, in the present embodiment, the protection guide 4 is provided in the front portion of the magnetic head 3 in the optical disc rotation direction, and the contact surface of the protection guide 4 with the optical disc 2 is made of the material forming the protective film surface 2a of the optical disc 2. A member 5 made of a material having a small dynamic friction coefficient is arranged. As the contact surface member 5, a material having a relationship that the coefficient of dynamic friction between the contact surface member 5 and the material of the protective film surface 2a of the optical disc 2 is smaller than the coefficient of dynamic friction between the materials forming the protective film surface 2a. To use. As a result, the frictional resistance between the optical disk 2 and the contact surface member 5 can be reduced, and scratches on the contact surfaces of both can be reduced.

As the contact surface member 5, among the materials having the above relationships, a plastic material having a low dynamic friction coefficient and a low hygroscopicity and being hard to deteriorate is suitable. Specifically, polycarbonate is generally used as the material of the disk substrate 2b of the optical disk 2, and acrylic resin that is cured by ultraviolet irradiation is used as the material of the protective film surface 2a. Contact that makes contact with the protective film surface 2a of the acrylic resin. The surface member 5 is preferably made of resin such as polyamide, polyacetal, polyvinyl chloride, polyethylene, or PTFE (trade name Teflon). As the material of the protective film surface 2a and the material of the contact surface member 5, a proper combination of materials having a low friction coefficient may be selected.

Incidentally, each of the above resins has a coefficient of dynamic friction with steel of 0.192, 0.129 and 0.21 respectively.
It is as small as 9, 0.139 and 0.117. On the contrary,
The dynamic friction coefficients of polycarbonate and polymethacrylate with steel are 0.302 and 0.568, which are relatively larger than the dynamic friction coefficients of the above-mentioned suitable combination materials. The above dynamic friction coefficient was quoted from "Dynamic Friction Coefficient of Various Plastics" on page 1076, Lubrication Handbook (edited by Japan Society of Lubrication).

As shown in FIG. 2, the applicant of the present invention has a simple structure in which a tape made of PTEF (product name Teflon) is attached to the surface of the protection guide 4, and the recording / reproducing operation of the optical disk device is effected. It was confirmed. As a result, as shown in the experimental data of FIG. 3, in the case where the conventional guide in which the tape made of PTFE (trade name Teflon) is not attached to the surface is used, the Tracking loss occurs during operation due to scratches,
While the recording error increased in that portion, in the device adopting the protection guide 4 of this embodiment, the increase in recording error could be greatly reduced even with the optical disc having the same scratch as above. In addition, by adopting the configuration of this embodiment, foreign matter such as sand dust that has entered from the outside can be protected from the magnetic head 3 and the optical disk 2.
Even if it is caught in the contact part with the contact part, it is less likely that the contact part is damaged.

The present invention is not limited to the configuration of the above embodiment, and various modifications can be made. For example, in the above, the protection guide 4 is provided separately from the magnetic head 3, but the protection guide 4
Need only have a function of holding the magnetic head 3 with a slight gap kept from the optical disk 2. A protective guide 4 is provided integrally with the magnetic head 3, and at least the contact surface with the optical disk is made of the above-mentioned material. It does not matter even if it has a structure with the above member. Further, as in the above embodiment, the protection guide 4
In the configuration in which the support arm 3a is disposed in the front part of the magnetic head 3, a flexible member is used for the support arm 3a in this part, the flexibility of movement of the protection guide 4 is increased, so that the optical disc When there is a foreign matter on the surface 2 and it hits the protection guide 4, the protection guide 4 can be retracted with respect to the foreign matter, and the occurrence of an error can be further reduced.

[0014]

As described above, according to the present invention, in the optical disc device having a simple structure in which the magnetic head comes into contact with the optical disc, the protection guide disposed in the front part of the magnetic head with respect to the rotating direction of the optical disc. Since the member with low dynamic friction coefficient is used for the contact surface with the optical disk, it is possible to protect the contact surface of the optical disk and the magnetic head from foreign matter such as dust entering from the outside, and even in the case of an already damaged optical disk. The occurrence of recording / reproducing errors can be reduced as compared with the conventional case, and the operational stability can be improved. Further, the structure for obtaining such a function can be realized only by adding a simple mechanism to the conventional device, which is economical.

[Brief description of drawings]

FIG. 1 is a plan view of an optical disc device according to an embodiment of the present invention.

FIG. 2 is a side sectional view of a magnetic head portion of the optical disk device.

FIG. 3 is a diagram in which operating characteristics of the device are measured.

[Explanation of symbols]

 1 optical disk device 2 optical disk 2a protective film surface 3 magnetic head 4 protection guide 5 contact surface member

Claims (1)

[Claims] 1. An optical head comprising: an optical head for irradiating a light beam spot on the optical disc; and a magnetic head for applying a modulated magnetic field in a state of being in contact with or in proximity to the optical disc, the optical beam being applied to the optical disc by the action of the light beam spot and the magnetic field. In an optical disc device for forming a pattern to record information and reproducing the recorded information by reading the pattern, the magnetic head is in contact with or in close proximity to the protective film surface of the optical disc, A protection guide is provided at the front of the magnetic head in the direction of rotation so as to prevent foreign matter from being damaged when the magnetic head and the optical disk are caught between the magnetic head and the optical disc. As a member of the contact surface with the optical disk, the coefficient of dynamic friction between the contact surface member and the protective film material of the optical disk is small. Optical disc apparatus characterized by using a material in engagement.