JP4103050B2 - Disk drive device - Google Patents

Description

  The present invention relates to a disk drive device that performs recording / reproduction driving of a disk-shaped information recording medium (disk) such as a CD or DVD, and in particular, suppresses vibration of the disk due to sound propagated from a speaker, and focus servo caused by vibration of the disk. The present invention relates to a disk drive device capable of preventing errors.

  Conventionally, CD players, DVD players, DVD recorders, and the like are known as disk drive devices and are generally widely used for awards. Such an apparatus includes a turntable that supports the center of the disc on the information recording surface side of the disc, a motor for rotationally driving the turntable, and irradiating the information recording surface of the disc with light. The pickup is configured to receive reflected light from the disc and a clamp plate that faces the turntable and sandwiches the disc between the turntable. In this case, the disk resonates due to the sound propagated from the speaker (air vibration), which may cause focus servo control to be disabled and cause sound skipping.

Therefore, the thickness of the disc substrate is t [mm], and the outer diameter of the clamp that holds the center of the disc substrate is dc [mm].
A proposal has been made to set 0.064 dc / 2−0.58 ≦ t ≦ 0.064 dc / 2−0.22 (for example, Patent Document 1).

  However, it is difficult to change the disk thickness according to the outer diameter of the clamp (clamping disk) in terms of production efficiency, and the outer diameter of the clamping disk varies depending on the model. Depending on the type of device that drives the servo, a servo error occurs due to the vibration of the disk.

  On the other hand, a first ring-shaped portion and a second ring-shaped portion are provided on the clamp plate (clamper), and a first antinode portion of the vibration (secondary portion of the disk) in the secondary vibration mode generated in the disk with a frequency in the vicinity of 700 to 800 Hz. There has also been proposed an apparatus in which a portion having a radius of 30 to 40 mm from the center) is pressed by a first ring-shaped portion and a second abdominal portion (peripheral portion of the disk) is pressed by a second ring-shaped portion ( For example, Patent Document 2).

JP 2001-344742 A

Japanese Patent No. 2550850

  However, a disc such as a CD or a DVD has a turntable that supports the central portion of the disc on the information recording surface side because a signal is recorded from an area having a diameter of 46 mm with a reading start portion called a lead-in area at the top. Since the diameter is set to 40 mm or less in consideration of the pickup entry area, the first and second ring-shaped parts in Patent Document 2 are located on the non-recording surface (information recording surface) of the disc at a position deviated from the periphery of the turntable. The surface is the side on which the irradiation light is incident from the pick-up, and the non-recording surface is the opposite side).

For this reason, the disk receives a pressing force from the first and second ring-shaped parts and curves in an umbrella shape against the turntable side (information recording surface side), and its peripheral edge comes into contact with the housing and pickup of the apparatus. There is a risk that reading of signals by the pickup may not be performed properly.

  Further, as in Patent Document 2, a large clamp disk having a second ring-shaped portion that presses the periphery of the disk increases the material cost and makes it difficult to reduce the size of the apparatus.

  In addition, in order to suppress the vibration of the disk, a separate felt is attached to the back surface of the clamp board, and the felt is generally contacted with the periphery of the center hole of the disk. In addition to being expensive, there is a problem that the attaching process is required and productivity is deteriorated. Further, even when the felt is attached, the vibration of the disk due to the propagation sound cannot be suppressed, and sound skipping may occur.

  The present invention has been made in view of the circumstances as described above, and its purpose is to suppress the vibration of the disk caused by the propagation sound without cost by a clamping board as small as possible, and to reproduce and drive it. It is an object of the present invention to provide a disk drive device that can be performed well.

In order to achieve the above object, the present invention
A turntable 2 for supporting the disk D having the center hole h around the center hole h inside the lead-in area on the one surface d1 side where the lead-in area is formed, and for rotating the turntable 2 A disc that includes a motor 1 and a clamp board 5 that faces the turntable 2 and sandwiches the disc with the turntable 2 from the other surface d2 side of the disc D, and records or reproduces information on the disc D In the drive device,
Protrusions 9 are provided in an annular region having a radius of 15 to 20 mm from the center of rotation of the clamp disk 5, and the other surface d2 side of the disk D is pressed only within the annular region by the projections 9. Features.

  According to the present invention, the convex portion provided on the clamp plate presses one side (non-recording surface) of the disc only within an annular region having a radius of 15 to 20 mm from the center of the disc, thereby causing a 600 to 800 Hz generated by the propagation sound. High-quality playback without sound skipping is possible by suppressing disc vibration.

  Further, since the convex portion presses one side (non-recording surface) of the disc only within an annular area having a radius of 15 to 20 mm from the center of the disc, the disc sandwiched between the turntable and the clamp plate is pressed by the convex portion. It is possible to reduce the cost by making the clamping disk having a convex portion the same size as the turntable without curving to the turntable side (information recording surface side).

  Furthermore, since the convex part is integrally formed with the clamp board, the clamping board and the entire apparatus can be efficiently produced without the sticking process as compared with the case of attaching the felt.

Hereinafter, the present invention will be described in detail with reference to the drawings. FIG. 1 is a cross-sectional view of a main part showing such a disk drive device. In FIG. 1, D is a disc (diameter 120 mm) which is a disc-shaped information recording medium such as a compact disc which is not covered with a cartridge case, unlike a mini disc. A hole h (diameter 15 mm) is provided. The disk drive according to the present invention is to record the music information to the disk D, used for and reproduces the recorded information.

  Reference numeral 1 denotes a motor capable of speed change (spindle servo) control, such as a DC motor constituting the disk drive device, and 2 is a disk-shaped turntable driven to rotate by the motor. It protrudes from the periphery of the hub 3 fixed to the drive shaft. The hub 3 is fitted into the center hole h of the disk D, and the turntable 2 supports one surface (information recording surface d1) side of the disk D around the center hole h. Incidentally, the surface of the turntable 2 that holds the disk D is smaller than the lead-in area of the disk D (the reading start area at a radius of 23 to 25 mm from the center), and the diameter is set to 26 to 33 mm. Further, the information recording surface d1 side of the disc in the present invention means the surface side irradiated with the signal reading light from the pickup 4, and the opposite side is the non-recording surface d2 side.

  The disk D is supported by the turntable 2 at the center on the information recording surface d1 side, and then sandwiched between the turntable 2 and the clamp board 5 facing the turntable. Is activated, the disk D, the turntable 2 and the clamp board 5 are integrally rotated in one direction.

  During the rotation of the disk D, the pickup 4 is moved in the radial direction of the disk D (thread servo) while performing tracking servo control, and light (from the pickup 4 to the information recording surface d1 of the disk D by focus servo control). Laser light) is irradiated in a focused state, and the reflected information from the disk D is received by the pickup 4 to read the recorded information.

  Here, the clamp disk 5 is a disk-shaped member arranged on the axis of the turntable 2, and a boss 6 that covers the tip of the hub 3 is formed at the center, and a magnet is formed on the outer periphery of the boss 6. 7 is arranged. A yoke plate 8 collects the magnetic lines of force of the magnet 7 on the turntable 2 side made of a magnetic material, and the disk D on the turntable 2 is pressed against the clamp plate 5 with an appropriate pressing force by the focusing magnetic force.

  In particular, the clamp 5 is formed with a convex portion 9 that presses the non-recording surface d2 side of the disk D on the surface facing the turntable 2, and the convex portion 9 prevents the disk D from slipping. ing.

  Further, the convex portion 9 functions to suppress the vibration of the disk D. That is, when the disk D is reproduced and driven, air vibration occurs due to the output of the speaker, and the disk D resonates due to the air vibration (propagation sound). However, the convex portion 9 is the vibration of the disk D caused by the propagation sound. And the focus servo control by the pickup 4 is properly performed.

  2 and 3 are bottom views of the clamp board having such convex portions. In particular, FIG. 2 shows an example in which the convex portion 9 has a flat small cylindrical shape (diameter: about 3 mm, height: about 1 mm). The convex portion 9 is R1 (15 mm) to R2 (20 mm) from the center of the clamp board 5. Within this range, a plurality (eight in this example) are formed at equal intervals in the circumferential direction of the clamp board 5.

  On the other hand, FIG. 3 shows an example in which the convex portion 9 has an annular shape, which has a predetermined width (5 mm in this example) and is within a radius R1 (15 mm) to R2 (20 mm) from the center of the clamp plate 5. Thus, it is formed continuously in the circumferential direction of the clamp disc 5.

  Since the clamping disk 5 clamps the disk D in a concentric state with the disk D, the convex portions 9 in FIGS. 2 and 3 are both non-existent in the annular region having a radius of 15 to 20 mm from the center of the disk D. The recording surface d2 side is pressed.

  FIG. 4 is a graph showing the vibration characteristics of the disk, and FIG. 5 is a graph showing the vibration suppression effect of 600 to 800 Hz depending on the position where the disk is pressed.

  As shown in FIG. 4, the resonance frequency of the disk is in the range of 600 to 1000 Hz (especially 600 to 800 Hz), and the focus servo characteristic prevents the occurrence of sound skipping because the gain decreases as the frequency increases. In order to perform appropriate focus servo control, it is necessary to suppress vibrations of 600 to 800 Hz.

  Therefore, as a result of repeated experiments using a disk having a diameter of 120 mm, a non-recording surface of the disk is pressed within a radius of 15 to 45 mm or a radius of 55 mm or more as shown in FIG. It was found that the vibration level of the sound became −20 dB or less and no sound skipping occurred.

In order to increase the vibration suppression effect of the disk at 600 to 800 Hz, it is most effective to press the vicinity of a radius of 30 mm. However, this increases the size of the clamp board and increases the cost. to elicit new problems such or curved like an umbrella on the information recording surface.

  Therefore, the present invention defines a minimum radius region of 15 to 20 mm that can prevent sound skipping as a disc pressing position, and a disc drive device having a clamp disc 5 having a convex portion 9 as shown in FIG. Led to the development.

  According to this, the diameter of the clamp disk 5 is 40 mm, which is the same as that of the turntable 2, so that the material cost is suppressed, and the convex portion 9 forms the non-recording surface d2 of the disk D on the peripheral edge of the turntable 2. Since the disk D is pressed, there is no possibility that the disk D is bent in an umbrella shape on the information recording surface d1 side and comes into contact with the pickup 4 or the like, and the convex portion 9 is integrally formed with a clamp board 5 made mainly of resin. The board 5 can be efficiently produced at low cost.

  FIG. 6 is a graph showing the vibration reduction effect of the disk when the clamp plate 5 having the small cylindrical convex portion 9 as shown in FIG. 2 is used. As can be seen from this figure, according to the disk drive apparatus using the clamp disk 5 according to the present invention, it is understood that the vibration of the disk at 600 to 800 Hz is suppressed. In FIG. 6, since the vibration peak appearing in the vicinity of 900 Hz is −20 dB or less, there is no problem of skipping sound.

  Although the present invention has been described above, the disk drive device can be applied not only to a reproduction-only machine such as a CD player but also to a DVD recorder having a reproduction / recording function.

  Further, the turntable 2 is not limited to a cross-sectional shape as shown in FIG. Furthermore, the positional relationship between the turntable and the clamp board may be the reverse of the above example. On the other hand, the convex part 9 should just be in the hatching range of FIG.

Sectional drawing which shows the principal part of the disc drive apparatus based on this invention Bottom view showing the clamp panel of the device Bottom view showing an example of changing the clamp panel A graph showing the vibration characteristics of the disc (state in which the center of the disc is clamped with a flat resin plate having a diameter of 40 mm) The graph which shows the vibration suppression effect of 600-800Hz by the presser position of a disk The graph which shows the vibration suppression effect of the disk by this invention

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Motor 2 Turntable 4 Pickup 5 Clamp board 9 Convex part D Disk d1 Information recording surface d2 Non-recording surface

Claims (2)

A turntable for supporting a disk having a center hole around the center hole inside the lead-in area on one side where the lead-in area is formed, a motor for rotating the turntable, and the turn In a disk drive device comprising a clamp disk that sandwiches the disk with the turntable from the other surface side of the disk facing the table, and records or reproduces information on the disk,
A convex portion is provided in an annular region having a radius of 15 to 20 mm from the center of rotation of the clamp disk, and the convex portion is configured to press the other surface side of the disk only within the annular region. Disk drive device to be used. 2. The disk drive device according to claim 1, wherein the convex portion is an annular shape integrally formed with the clamp board.

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