KR19990039987A - disk - Google Patents

Abstract

The present invention relates to a disk capable of preventing the disk from warping due to thermal deformation due to the difference in temperature distribution in the disk.

The disk of the present invention includes a circular disk plate having a predetermined inner diameter; The disk plate is characterized in that it comprises a plurality of thermal stress blocking means formed in the inner diameter in order to block the thermal deformation due to the thermal stress caused by the temperature rise of the inner peripheral portion.

According to the present invention, by forming a plurality of slots in the inner diameter of the disk to block the thermal stress of the inner peripheral portion, it is possible to prevent the warping phenomenon of the disk due to the thermal strain due to the difference in the temperature distribution in the disk.

Description

Disc

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recording medium, and more particularly to a disc capable of removing thermal stress due to a difference in temperature distribution present on the disc.

In recent years, an optical disc has become a general trend as a recording medium capable of recording and reproducing information. An optical disc can be roughly divided into a disc for reproduction only, a disc which can be recorded only once, and a disc which can be repeatedly recorded. In addition, optical discs capable of repeating recording can be classified into phase change type optical discs and magneto-optical discs according to recording and reproducing methods. Phase-changeable optical discs record information by phase-changing the coupling structure of a recording surface using a light beam. A typical example is a large-capacity so-called Digital Versati1e Disc-Random Access Memory (DVD-RAM) disc. There is. A magneto optical disc is a method of recording information by magnetic field modulation using a magnetic head and reproducing information by detecting a change in polarization angle according to the optical-magnetic field conversion characteristic using a light beam.

In general, the optical disks are driven by a spindle motor. When the disk is driven for a long time, the temperature distribution in the disk is affected by effects such as heat generation of the spindle motor. In other words, as the spindle motor is driven for a long time and heated, the temperature of the disk inner peripheral portion to be clamped is higher than the temperature of the outer peripheral portion. As a result, the temperature distribution in the disk is not constant, and thermal deformation occurs according to the temperature difference, causing the disk to be distorted. Looking at the problem of the disk in detail with reference to the accompanying drawings as follows.

1 is a perspective view showing a conventional optical disk, in which an optical disk 10 is generally composed of a recording and reproducing portion 10a in which information is recorded and reproduced, and a clamping portion 10b clamped.

The optical disk 10 shown in FIG. 1 is a circular disk having a center hole 10c formed therein, and a clamping portion 10b formed at an inner circumference thereof is a portion clamped by a clamping cap when mounted to a spindle motor (not shown). . This allows the disk 10 to be driven stably. However, when the optical disk 10 is mounted on the spindle motor and driven for a long time, the clamping portion 10b receives heat compared to the outer peripheral portion.

In detail, the temperature of the clamping portion 10b of the disk is caused by the temperature rise due to the heating of the spindle motor, that is, the temperature rise due to the rotational friction and the temperature rise of the lubricant in the bearing portion, etc., and the variation of the clamping force of the clamping cap. Due to the friction of the clamping portion, etc., it rises above the outer peripheral portion. In addition, due to the difference in speed of air flow generated on the surface of the disk when the disk is driven, the outer peripheral portion of the disk is easy to cool, but the inner peripheral portion is relatively slow. Thus, the temperature distribution present on the disk is not constant as shown in FIG. Referring to FIG. 2, when the disk is driven for a long time, the temperature Ti of the inner circumference portion is relatively higher than the temperature To of the outer circumference portion.

As described above, in the conventional disk, a difference in thermal deformation occurs according to a difference in temperature distribution present in the disk. In other words, the thermal strain of the inner circumference of the disk having a relatively high temperature is greater than the thermal strain of the outer circumference due to the repeated driving of the disk. For this reason, there is a problem that a buckling phenomenon, that is, a distortion phenomenon occurs in the disk.

In particular, in the case of a conventional disk, when the strain in the circumferential direction, which is longer than the strain in the radial direction, is not uniform, the surface of the disk does not maintain a plane as shown in FIG. 3A. In FIG. 3A, the solid line represents the deformed disk, and the dotted line represents the deformed, i.e. ideal disk. In addition, when the strain in the circumferential direction of the disk is not uniform, it causes a bending phenomenon that locally protrudes from the surface of the disk as shown in FIG. 3B. FIG. 3B is an enlarged view of a portion of the inner diameter portion of FIG. 3A. In FIG. 3B, a is a portion in which the disc is bent in the height direction by deformation in the circumferential direction of the disc.

As described above, the conventional disk is warped due to the nonuniform thermal strain due to the temperature difference, thereby causing a large problem such as a tracking error during recording and playback.

Accordingly, it is an object of the present invention to provide a disk capable of preventing the disk from warping due to thermal deformation due to the difference in temperature distribution in the disk.

Another object of the present invention is to provide a disk capable of preventing the disk from warping due to thermal deformation in the circumferential direction.

1 is a perspective view showing a conventional optical disk.

2 is a temperature distribution chart in a disk by driving the disk.

3 is a diagram showing thermal deformation of a disk due to a difference in temperature distribution in a conventional disk.

4A is a perspective view showing an optical disk according to the present invention, and FIG. 4B is a top view of the optical disk.

5 is a top view of an optical disk according to another embodiment of the present invention.

6 is a temperature distribution diagram inside a disc when the air outside the disc is hot.

FIG. 7 is a diagram showing the thermal strain of the slot region in the optical disk shown in FIG. 4. FIG.

* Brief description of symbols for the main parts of the drawings

10, 20, 30: optical disk 10a, 22a: recording and playback portion

10b, 22b: clamping part 10c, 22c, 32c: center hole

24, 34: inner peripheral slot 36: outer peripheral slot

In order to achieve the above object, the disk according to the present invention comprises a circular disk plate having a predetermined inner diameter; It characterized in that it comprises a plurality of first thermal stress blocking means formed in the inner diameter in order to block the thermal deformation due to the thermal stress caused by the temperature rise of the inner peripheral portion of the disk plate. In addition, the disk according to the present invention further includes a plurality of second thermal stress blocking means formed on the outer diameter of the disk plate in order to block thermal deformation due to thermal stress caused by the temperature rise of the outer circumference of the disk plate.

Other objects and advantages of the present invention in addition to the above object will become apparent from the description of the preferred embodiment of the present invention with reference to the accompanying drawings.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to FIGS. 4 to 7.

4 illustrates an optical disk according to an embodiment of the present invention, where FIG. 4A is a perspective view of the optical disk and FIG. 4B is a top view of the optical disk.

Referring to FIG. 4, the optical disk 20 of the present invention includes a disk plate 22 and a plurality of inner peripheral slots 24 formed in the inner diameter of the disk plate 22.

In the optical disk 20 of FIG. 3, the disk plate 22 is a circular shape in which the center hole 22c is formed, and consists of a clamping portion 22b and a recording and reproducing portion 22a from the inner circumference to the outer circumferential direction. The clamping portion 22b is a portion clamped by a clamping cap (not shown), and a plurality of inner circumferential slots 24 are formed at predetermined intervals in the inner diameter of the clamping portion 22b. The inner circumferential slot 24 serves to remove the thermal stress caused by the temperature rise in the inner circumferential portion of the disk plate 22. Accordingly, even if the inner circumferential portion of the disk plate 22 is expanded in the circumferential direction, the disk 20 is not twisted. In other words, when the inner circumferential portion of the disk plate 22 is expanded in the circumferential direction due to the heat generation of the spindle motor for driving the disk, the size of the inner circumferential slot 24 is reduced as shown in FIG. 7. do. In this way, the inner peripheral slot 24 absorbs the heat deformation component due to the thermal stress of the disk, thereby preventing the disk plate 22 from being warped.

FIG. 5 is a top view illustrating an optical disk according to another embodiment of the present invention, wherein the optical disk 30 of FIG. 5 includes a disk plate 32 and a plurality of inner and outer diameters of the disk plate 32. Inner and outer peripheral slots 34 and 36 are provided.

In the inner diameter of the disc disk 32 of the optical disk 30 of FIG. In addition, when the outside air of the disk 30 is high, a plurality of outer peripheral slots 36 are spaced at regular intervals in the outer diameter of the disk plate 32 in order to remove thermal stress as the temperature of the outer peripheral part of the disk plate 32 rises. Is formed. As shown in FIG. 6, the outer circumferential slot 36 is formed in the disk plate 32 as the outer circumferential temperature To of the disk plate 32 rises above the temperature Ti of the inner circumference when the outside air of the disk is hot. When the outer peripheral portion is expanded in the circumferential direction, its size is reduced as shown in FIG. That is, the heat deformation component due to the thermal stress of the disk is absorbed in the slot 36. As a result, warpage of the disk substrate 32 due to thermal expansion of the inner and outer peripheral portions of the disk substrate 32 can be prevented.

As described above, in the optical disk according to the present invention, since a plurality of slots are formed in the inner diameter of the disk, it is possible to eliminate thermal stress in the inner circumferential portion due to the repeated driving of the disk. In addition, since the slot is formed in the outer diameter of the disk, it is possible to eliminate the thermal stress caused by the temperature rise of the outer peripheral portion. Accordingly, it is possible to prevent the disk from warping due to the thermal strain caused by the difference in temperature distribution in the disk. Furthermore, information recording and reproduction on the disc can be performed stably.

On the other hand, although the present invention has been described only the optical disk, those skilled in the art will appreciate that it can be applied to conventional disks.

In other words, those skilled in the art will appreciate that various changes and modifications can be made without departing from the spirit of the present invention. Therefore, the technical scope of the present invention should not be limited to the contents described in the detailed description of the specification but should be defined by the claims.

Claims (3)

A circular disk plate having a predetermined inner diameter; And a plurality of first thermal stress blocking means formed in the inner diameter in order to block thermal deformation due to thermal stress caused by a temperature rise of the inner circumference of the disk plate. The method of claim 1, And a plurality of second thermal stress blocking means formed on an outer diameter of the disk plate so as to block thermal deformation due to thermal stress caused by a temperature rise in the outer circumference of the disk plate. The method according to claim 1 or 2, The thermal stress blocking means is a disk having a predetermined interval, characterized in that formed in the form of a slot.