KR101255342B1 - cover for reducing fluttering of optical disc and optical disc drive adopting the same - Google Patents

Abstract

Disc disc reduction cover and an optical disc drive using the same are described. The cover comprises: a body having a top surface covering a disk seated on a spindle of the optical disk drive; And a bead formed in the body and having an asymmetrical shape about a central portion of the disk.

Description

Cover for reducing fluttering of optical disc and optical disc drive adopting the same}

The present invention relates to a housing capable of suppressing the shaking of an optical disk rotating at a high speed in the housing and an optical disk drive employing the same.

In an optical disc drive, a strong air flow occurs in a narrow space between the high speed rotating disc and the top cover that covers it. This air flow causes the disk to vibrate. This air flow is compounded by the rotation of the disk. That is, on the disk surface, a spiral air flow (flow) is formed by the Coriolis effect and the viscous flow in the boundary layer, and the pressure decreases along the inner surface of the top cover. Inflow of air into the disk center region occurs.

The rotation of the disk causing this complex air flow causes an interaction between the disk and the air, the movement of the disk changes the flow of air, the altered flow of air again deforms the disk, this interaction of the disk It gets worse as the speed increases. This interaction causes disk fluttering.

The tremor of the disk worsens the stability of the disk, and the tremor of the disk makes the data inaccessible, i.e. writing and reading of the data impossible.

Beads formed on the top cover increase the rigidity of the top cover and suppress vibration of the top cover due to air flow. However, the beads affect the air flow in the narrow gap between the top cover and the disk and therefore a proper design is required.

According to the present invention, a disk cover capable of effectively suppressing vibration of a disk and an optical disk drive employing the same are provided.

According to one type of the invention,

A body having an upper surface portion covering a disk seated on a spindle of the optical disk drive;

A cover for an optical disc drive is provided which is formed in the body and has a bead having an asymmetrical shape about a central portion of the disc.

According to another type of the invention,

A main frame mounted with a spindle motor on which a disk is seated and an optical pickup corresponding to the disk;

The optical disk drive is coupled to the main frame and is formed on the body covering the disk and includes a cover having a bead of asymmetrical shape about the disk.

According to one embodiment of the invention, the body may be provided with a disk clamper corresponding to the spindle.

According to another embodiment of the present invention, the body may have an upper surface portion on which the beads are formed and a side portion corresponding to the main frame provided in the optical disk drive.

According to another embodiment of the present invention, the bead may have a symmetrical shape with respect to at least one of a first direction parallel to the disk and a second direction orthogonal thereto.

According to another embodiment of the present invention, the bead has a symmetrical shape with respect to at least one of a first direction parallel to the disk and a second direction orthogonal thereto, and asymmetrical with respect to the other direction. Can have

According to another embodiment of the present invention, the bead may have a quadrangular shape on the plane of the body.

According to another embodiment of the present invention,

The bead has a bottom surface recessed toward the disk, the bottom surface can be tilted with respect to the top surface of the disk.

According to another embodiment of the present invention, the bottom surface is generally flat.

According to another embodiment of the present invention, the bottom surface is generally flat, and a sidewall of an asymmetric height may be formed around the bottom surface.

According to the cover according to the present invention having an asymmetric height bead, the optical drive for recording data on an optical disc such as a CD, a DVD, a BD, etc., can be used for disc deformation due to disc resonance caused by a low speed disc drive. It is possible to stably record data on the disc by reducing and effectively reducing the disc shaking phenomenon occurring during high-speed disc rotation.

1 is an exploded perspective view of a disk shake reduction cover and an optical disk drive using the same according to an embodiment of the present invention.
2 is a perspective view of a cover for an optical disk drive according to the present invention.
3 is a cross-sectional view taken along the line AA of FIG. 2.
4 is a plan view of the cover for the optical disk drive shown in FIG.
5 is a plan view of a cover for an optical disk drive according to another embodiment of the present invention.
6, 7, 8 show the pressure distribution on the upper surface of the disk represented by the two conventional covers and the cover according to the invention.
Figure 9 shows the pressure difference between the upper and lower disks by the conventional two covers and the cover according to the present invention.

Hereinafter, with reference to the accompanying drawings will be described in detail an embodiment of the disk shake reduction cover according to the present invention and an optical disk drive applying the same.

1 is an exploded perspective view of a disk shake reduction cover and an optical disk drive using the same according to an embodiment of the present invention.

Referring to FIG. 1, an optical disc drive includes a main body 10 and a cover 20 covering the main body 10. The main body 10 includes a main frame 11 supporting the entire structure, a tray 12 accommodating the disc 1 and reciprocating the inside and the outside of the main frame 11, and a disc transferred into the main frame 11. A spindle 14 on which (1) is mounted, an optical pickup 13 and a transport mechanism 15 of the optical pickup, which are disposed corresponding to the recording surface of the disk 1 mounted on the spindle 14, are provided.

Meanwhile, the body of the cover 20 covering the main body 10 includes an upper surface portion 21 corresponding to an upper surface of the frame 11 or an upper surface of the disk and two side portions 22 corresponding to both sides of the frame 11. Equipped. The upper surface portion 21 is provided with a bead 23 in the form of a recess in a substantially rectangular shape toward the main frame 11 side, a clamper hole 24 in which the disk clamper 30 is rotatably installed is formed at the center thereof. have.

The bead 23 has a rectangular rim bottom surface 231 which is inclined with respect to the top surface of the disk in accordance with a feature of the invention. Specifically, the beads 23 are generally flat bottom surface 231 recessed from the upper surface portion 21, inclined sidewalls 232 on both sides of the bottom surface 231, and a central donut shaped wheel wheel. Has (233). The bottom surface 231 is generally flat and, in accordance with a feature of the invention, is formed, for example, inclined at a different height than the top surface of the disc 1 for each part. Thus, as shown in FIG. 2, the sidewalls 232 surrounding the bottom surface 231 have four sidewalls 232a, 232b, 232c, and 232d. Among them, the first and third sidewalls 232a and 232c have different heights as a whole, and the second and fourth sidewalls 232b and 232d are tapered to form the second sidewall 232c in the first sidewall 232a. Its height gradually increases in the direction toward.

FIG. 3 is a cross-sectional view taken along the line A-A of FIG. 2, showing the relationship between the disk 1 and the bottom surface 231. As shown, the distance between the bottom surface 231 and the disk 1 of the outermost part of the drawing located farthest to the top surface of the disk 1 is t2, and the distance on the right in the drawing is t1. Where t2 is greater than t1. This height difference brings about a local pressure difference on the upper surface of the disk when the disk 1 mounted on the spindle 14 is rotated by the disk clamper 30 at high speed.

The technical feature of the present invention is that the pressure on the upper surface of the disc 1 is differentially differentiated for each part by differentiating the depth or height of the bottom surface 231 of the bead 23. This technical feature is, as shown in Figure 4, the overall shape of the bead 23 is substantially symmetrical structure in the left and right (x-x ') and up and down (y'-y) direction, or left or right It can be applied to structures that are only approximately symmetrical in the direction. 5 shows another example of the bead 23 'symmetrically in the left and right direction around the boundary line in the up and down direction (y'-y). Referring to FIG. 5, the beads 23 ′ have four side walls 232a, 232b, 232c, and 232d. Here, reference numerals 232a ', 232b', and 232d 'correspond to the first sidewall 232a, the third sidewall 232c, and the fourth sidewall 232d described above, respectively, and have a curved arc (or arc) second shape. Sidewall 232b 'corresponds to the second sidewall 232b described above. This illustrates that the beads 23 ′ may have an approximately symmetrical shape in only one direction. The bottom surface of the beads is preferably sized to sufficiently cover the top surface of the disk.

As described above, the present invention partially differentiates the pressure on the upper surface of the disk. As an exemplary structure, the bottom of the beads 23 and 23 'is inclined with respect to the upper surface of the disk 1. .

In the past, the distance between the bottom of the bead and the disk was generally constant. The vibration or vibration of the disk according to the bead structure was confirmed by the present inventors, and the present invention was derived as a result of various experiments to improve the problem. Could.

Today's optical drives spin discs at various rotation speeds, from 30Hz to 230Hz, to record and read data. This wide band operation makes it impossible to avoid the disc resonance phenomenon during data recording and reproducing, and in particular, the abnormal disc resonance phenomenon occurring in a specific rotational speed region causes great difficulty in recording and reproducing. This phenomenon is prominent in a high-speed optical disc drive of a half-height type.

The bead is introduced to suppress disk shaking in high speed driving. When the gap between the bottom surface and the disk is constant as in the prior art, the space between the disk and the cover is narrowed by the height or depth of the bead. In this case, it restricts the flow of air supplied along the inner surface of the cover toward the center of the disk, and increases the flow rate of air flowing from the center of the disk to its outer direction. To make it lower. This pressure reduction reduces the tremor of the high speed drive disk disc, but in low speed drive the narrow space and pressure reduction between the disc and the cover exacerbates the tremor of the disc rather than the beadless cover.

 According to the bead having the inclined bottom surface, that is, the asymmetric height, which induces the pressure difference with respect to the upper surface of the disk as described above, the vibration of the disk generated in the high speed drive is suppressed, The vibration of the disk can be suppressed.

Referring to FIG. 3, which shows a bead structure according to an exemplary embodiment, the bottom surface 231 of the bead 23 formed on the top surface of the cover 20 may have a flow of air on the top surface of the disk 1. By inducing different effects on the left and right sides, it is possible to reduce both the disk resonance and the disk flutter caused in the low speed driving and the high speed driving. Beads, in particular the bottom surface of the beads, impede the movement of air as it flows between the inside and the outside of the bottom and apply pressure to the disk. For example, the bottom surface can be designed with 2mm on the left and 4mm on the right. That is, the depth of the first sidewall may be 2 mm, and the depth of the third sidewall may be 4 mm.

As described above, in an optical disc drive, a flow of air occurs due to the rotation of the disc when the disc is rotated, which flows helically from the inner circumference (center area) to the outer circumference (peripheral area) of the disc and the disk surface according to the flow. Pressure on the pressure varies. To understand this flow phenomenon, flow analysis of steady state pressure distribution was conducted. 6, 7, and 8 show pressure distribution on the upper surface of the disk, FIG. 6 shows a conventional cover having a flat upper surface without beads (conventional structure 1), and FIG. 7 shows a conventional cover having beads of the same depth or height. (Prior Structure 2), and FIG. 8 shows simulation results of applying the cover according to the present invention having beads of different depth or height according to the present invention.

In the pressure distribution diagram of FIG. 6 according to the conventional structure 1, the pressure distribution in the central portion of the disc shows that the region represented by the dark system expressing the low pressure has the smallest size in the conventional structure 1 without the beads and thus It can be seen that the pressure in the intermediate region between the central region and the peripheral region is higher than that of the conventional structure 2 with beads and the structure of the present invention, as shown in Figs.

On the other hand, according to the conventional structure 2 having the same height beads showing the pressure distribution diagram of FIG. 7, the pressure of the intermediate region is the lowest, and the structure of the present invention has the asymmetric height beads shown in the pressure distribution diagram of FIG. According to the present invention, the pressure distribution of the middle size of the pressure distribution shown in the two types of conventional covers is shown. This phenomenon is constrained by the bead structure of the air flow from the inner circumference to the outer circumference or from the outer circumference to the inner circumference. The disk shake caused by the interaction of the disks is suppressed.

Referring to FIG. 9, the above result is clarified by the result of FIG. 9 which analyzes the distribution of the pressure difference between the lower and upper surfaces of the disk according to the shape of the cover or the shape of the bead according to the position of the disk. In the graph, # 1 is the cover of the conventional structure 1 without the bead, # 2 is the cover of the conventional structure 2 having the rectangular bead of the same height, and # 3 is the pressure difference analysis between the upper and lower surfaces of the cover according to the present invention. The results are shown respectively.

The greater the difference between the upper and lower pressures in the middle region of the disk, the better the disk shake effect. This is because the disk vibration is caused by the interaction between the disk and the air, which reduces the interaction with the air. The large pressure difference between the upper and lower surfaces in the middle region is caused by the lower pressure on the upper surface. It has the effect of alleviating disk shake caused by interaction.

However, in the disc resonance phenomenon, the pressure applied to the disc at the upper and lower surfaces is good throughout the disc because it acts as a force that resists the disc deformation when the disc resonance occurs, and thus can act as an air damper to alleviate the disc deformation. The cover of the proposed (# 3) is preferred so that the pressure differential distribution is small across the entire disc area.

Therefore, an appropriate pressure distribution is required in order to have a proper response force to the disk vibration and the disc resonance phenomenon. According to the cover of the present invention, the air flow is restricted on one side and smoothly on the other side, so that it can be applied to both high and low speed driving. The pressure distribution has been optimized for this purpose.

Table 1 below compares the deformation sizes of the different disks with the conventional structure 1, the conventional structure 2, and the structure of the present invention.

Conventional Structure 1 Conventional Structure 2 Invention Disk strain size 70㎛ 170 μm 60 탆

Through Table 1 above it can be seen that the cover according to the present invention is most advantageous in terms of disk deformation size. As a result, in the optical drive for recording data on an optical disc such as a CD, DVD, BD, etc., the present invention reduces disc deformation due to disc resonance caused by low-speed disc drive, and generates a disc during high-speed disc rotation. This effectively reduces the fluffing, making it possible to stably write data to the disc.

1: disc
10: optical disc drive body
11: main frame 12: tray
13: optical pickup device 14: spindle
15: Transfer mechanism of the optical pickup
20: top cover
21: Top portion 22: Side portion
23: Bead 231: Bottom surface
232: side wall 233: wheel part
24: clamper hole 30: clamper

Claims (15)

A body having an upper surface portion covering a disk seated on a spindle of an optical disk drive; having a bottom surface formed on an upper surface portion of the body in a form recessed toward the disk so as to differentiate the pressure on the upper surface of the disk by portions A bead having an asymmetrical shape about a central portion of the disc; And
And a clamper hole formed in the center of the bead, in which a disk clamper for clamping the disk is mounted on the spindle. delete The method of claim 1,
And the body has side portions corresponding to a main frame provided in the optical disk drive on both sides of the upper surface portion. The method of claim 1,
And the bead has a symmetrical shape with respect to at least one of a first direction parallel to the disk and a second direction orthogonal thereto. The method of claim 1,
The bead has a symmetrical shape with respect to at least one of a first direction parallel to the disk and a second direction orthogonal thereto, and has an asymmetrical shape with respect to the other direction. cover. The method of claim 1,
And the bead has a quadrangular shape in the plane of the body. The method according to any one of claims 1 and 3 to 6,
And the bottom surface is inclined with respect to the top surface of the disc. The method of claim 7, wherein
And the bottom surface is entirely flat. The method of claim 7, wherein
The bottom surface is generally flat,
A cover for an optical disc drive, wherein sidewalls having an asymmetric height are formed around the bottom surface. A main frame mounted with a spindle motor on which a disk is seated and an optical pickup corresponding to the disk;
A cover covering the disk to be coupled to the main frame;
Cover:
A body having an upper surface portion covering the disk;
A bead having an asymmetrical shape about a central portion of the disk having a bottom surface formed on an upper surface of the body in a form recessed toward the disk so as to differentiate the pressure on the upper surface of the disk by portions; And
And a clamper hole which is formed in the center of the bead and is mounted with a disk clamper for clamping the disk to the spindle. delete 11. The method of claim 10,
And the body has side portions corresponding to side surfaces of the main frame on both sides of the upper surface portion. 11. The method of claim 10,
And the bead has a symmetrical shape with respect to at least one of a first direction parallel to the disk and a second direction perpendicular to the disk. The method according to any one of claims 10, 12, 13,
The bead has a bottom surface recessed toward the disc,
And the bottom surface is inclined with respect to the top surface of the disc. 15. The method of claim 14,
The bottom surface is generally flat,
An optical disk drive, characterized in that the side wall of the asymmetric height is formed around the bottom surface.

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