JPS58114352A - Disk reproducer - Google Patents

Abstract

PURPOSE:To improve the flatness of a disk when viewed from a pickup and at the same time to prevent the deflection of the disk due to an external shock, by holding the outer circumference of the disk with two viscoelastic rolls which are positioned on the locus line of the pickup. CONSTITUTION:A disk 5 is put on a turntable 4 and turned by a motor 3. The 1st viscoelastic roll 10 is provided on an extended line of the locus of an optical pickup 7 which shifts right and left on the lower surface of the disk 5. This roll 10 has no up-down movement. The downward force is applied by means of a spring, etc. to the 2nd viscoelastic roll 11 which is attached to a cover body 2. When the cover 2 is closed, the disk 5 is turned and then held by a disk clamper 6. Therefore the disk 5 turns with a control given so that its surface deflection is minimum on a straight line connecting the table 4 and the roll 10 since the outer circumference of the disk 5 is held with rolls 10 and 11. As a result, the pickup 7 works at the area where the surface deflection of the disk 5 is minimized.

Description

[Detailed description of the invention] The present invention relates to a disc player playback device.

Systems for recording video signals and digital audio signals at high density, called so-called video discs and display audio discs, are becoming more common.

Some of these OV stems O use a laser to pick up information signals from a disk without any contact. This type of disc information shiratsuta is called pissi, so it has 6* unevenness.
I! It is a L animal, and its size is α5 in width.
The length of the vines is 0.9 to &5 pMs, the footer pitch is 5 minute layers (1-7 layers), and in order to optically pick up information signals from the vines such as ζO, the laser spot is on the disk. Therefore, the size of the laser beam must be approximately the same as the diameter IP. Therefore, it is necessary to irradiate the laser beam onto the disk by constricting the laser beam to a value of ν, which does not have an arbitrary aperture ratio. In order to keep the laser spora F constant, it is necessary to keep the information plane and OI [separation] of the lens and disk constant.

However, if the disk is perfectly flat, the distance between the lens and the information surface of the disk is considered to change as the disk rotates. Therefore, the omniscient focus servo technology, which requires some kind of means to provide a tracking function to the lens, optically detects defocus using the optical center tK and drives the lens in one direction. However, since it drives a lens, an object with a finite mass, there is a limit to the acceleration that can be generated.

That is, if the surface runout of the disk is large or if a sudden impact is applied from the outside, tracking may become impossible.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a disc playback device that improves the flatness of the disc as seen from an optical pickup and prevents vibration of the disc due to external shocks.

An embodiment of the invention is shown in the drawings. That is, this disc playback device is broadly divided into a sieve body 1 and a lid body 2, which are connected by a hinge (not shown) so as to be openable and closable. A motor 3 is attached to the casing IK, and rotates the turntable 4 using a so-called direct left drive method. A disk 5 is placed on the turn tape A/4, and the disk 5 is pressed against the turn tape A/4 by a disk clamper 6 provided on the lid body 2. Needless to say, the disk clamper 6 rotates together with the disker 5.

The casing IK is provided with an optical pickup 7 so as to face the lower surface of the disk 5, and is moved in parallel along a rail 9 by a scolder. A first viscoelastic roller lO is rotatably provided on the top surface of the housing on an extension of the trajectory of the optical pickup 7, and a second viscoelastic roller lO is provided on the bottom surface of the lid body 2.
The disk 5 is sandwiched between the viscoelastic roller 11 and the viscoelastic roller 11 . The tenth viscoelastic foot 10 is kept stationary in the vertical direction, and the viscoelastic lobe 11 of ts2 is configured to apply downward pressure by a spring or the like. Both lobes are attached to their respective rotation axes so as to rotate with little friction.

If we now place the disk 5 and close the lid 2, considering the nine-stage system, the disk 5 will be placed on the turn tape J using the disk clamper 6.
v4 and is also attached to the first roller 10KlfL by the second roller 11.

As a result, disk 5#il-ndeep A/4 and
Directly connect with the roller 10! It rotates while being regulated so that surface runout is minimized at II. Since the optical pickup 7 moves in parallel on the 01 line, the optical pickup 7 is picked up at the part with the least surface runout. Even with external shocks and vibrations, the vibrations can be suppressed to a small level in the rounding area where the outer periphery is sandwiched between 2I1ml viscoelastic rollers 10 and 11 and the portion of the disc 5 that is in contact with the pickup 7 is damped.

As described above, since the disc playback lid of the present invention is configured to press the outer circumference of the disc with the viscoelastic lobe, it has the effect of reducing disc deformation and disc surface torsion caused by external vibration, etc., and the focus servo This greatly improves the tolerance to external disturbances. As a result, it is particularly advantageous for devices that play back high-density recording discs with optical pickups), and also enables the practical use of portable and vehicle-mounted video disc playback devices and digital audio disc devices. The effect is great.

[Brief explanation of the drawing]

The figure is a cross-sectional view of a disc reproduction mounting device according to an embodiment of this IA Ming.

Claims (1)

[Claims] ■ An in-deep p rotatably supporting the disk;
A disc reproducing device comprising a mo I for driving an I-v table in positive rotation, and a viscoelastic lobe for pressing the disc by coming into contact with the outer shoulder of the disc O. (to) A disc playback device according to claim 1, wherein the viscoelastic ropes sandwich the disc in pairs. (Intuition) The disc reproducing device according to claim ?) or ?), wherein the viscoelasticity is located on the trajectory line of the pickup.