JPS6030849Y2 - disk drive - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a disk drive device suitable for driving video disks.

In recent years, video discs and recording/playback devices for them have been developed.

These types of devices can be broadly divided into those that scan the recording grooves of the disk with a needle, detect changes in the recording grooves as mechanical changes, and convert this into electrical signals, and those that scan the recording grooves of the disk with information based on the recording grooves. There are two types: one that reads optically.

FIG. 1 schematically shows the latter reproduction device,
A disk 1 on which information is recorded using grooves (pits) like an audio record is connected to a shaft 3 of a motor 2, and the disk 1 is rotated at high speed.

An optical system for reading is arranged below the disk 1. First, a helium neon laser 4 is provided as a light source, and a translucent prism 5 is arranged in the straight direction of the laser beam emitted from the laser. ing.

This prism 5 refracts the beam toward the disk 1 by about 90', but allows the returning beam reflected by the disk 1 to pass through without being refracted.

6 is a first mirror that reflects the reciprocating beam;
It is used to change the course by approximately 90 degrees.

Reference numeral 7 denotes a second mirror, which reflects the outgoing beam in the direction of the disk 1 and reflects the returning beam in the direction of the first mirror 6.

Note that this second mirror 7 is pivotally supported, and its rotation can be electrically controlled as required.

8 is a beam focusing device for focusing the beam.

9 is a photodetector for detecting the returning beam reflected by the disk 1;

The above-described prism 5, mirror 6, rotating mirror 7, beam focusing device 8, and photodetector 9 are integrated into an optical system device 10.
This optical system device 10 is placed on a rail 11 and is movable in the radial direction of the disk 1.

In addition, 12 is a holding box, 13 is a support stand, 14 is a holding cylinder, 1
5 is the outbound beam, and 16 is the return beam.

2 and 3 show the recording state on the disc 1 and the relationship with the beam, and the signal shown in FIG. 2A, which is an FM modulated video signal, passes through the limiter, A signal like B is obtained, and a corresponding groove or pit 17 is formed as shown in FIG. 2C.

The width of this pit 17 is approximately 1μ, the distance between adjacent pits is approximately 1μ, the depth is approximately 18λ (where λ is the wavelength of the laser beam), and is approximately 0.15μ, and the length of the pit is the length of the disk. There is a difference between the inner circumference and the outer circumference, and it also varies depending on the frequency of the FM modulated wave, and is, for example, 1.5 to 6 μ.

The pits 17 are shaped like a spiral or concentric circles on the disk surface, and form the first field (odd field) of a raster scanning television receiver in 1/2 FE circumference, and form the first field (odd field) in the remaining 1n circumference. Embodying 2 fields (even number field),
One round constitutes one frame.

The outer circumference diameter of the pits 17 is approximately 300+y+
mφ, the inner circumferential diameter is about 70 to 80 mm, and the surface is plated with gold or aluminum.

In the apparatus configured as described above, if the disk 1 is rotated and the pit 17 is scanned with a laser beam, the pit 1
Information based on the array of 7 can be read out.

To explain this in more detail, helium, neon,
A laser beam 15 is sent out from the laser 4, refracted approximately 90 degrees to the right by the prism 5, further reflected toward the center of the disk by the first mirror 6, and then reflected toward the disk by the second mirror 7. The reflected light is focused by a focusing device 8.
The beam is focused and irradiated onto the track where the pits 17 are arranged.

If the beam is irradiated onto an area where there are no pits, the beam will be reflected from the disk surface and return along the same trajectory.

However, when returning to the prism 5, the prism 5 is configured so that the returning beam 16 passes through it, so the photodetector 9 detects this beam.

On the other hand, when the beam is irradiated onto the pit 17, the beam spot is larger than the width of the pit 17, so the light reflected inside the pit 17 and the light reflected outside the pit interfere with each other. They cancel each other out, and almost no output is produced.

In other words, the reflected beam 16 becomes weak and can be detected by the photodetector 9 in distinction from when the beam is irradiated onto areas other than pits.

By scanning the track with the beam in this way, one frame of video information can be obtained.

Frame changes are made by moving the optical system 10 radially along the rails 11.

In addition, in the case of this optical scanning, since mechanical tracking is not performed by the guide groove, in addition to the central readout beam 18, a tracking beam is simultaneously transmitted from the same optical system device 10, as shown in FIG. 2C. 19, 20 beam 18
In FIG. 2C, beam 19 is located below the pit 17, beam 20 is located above the pit 17, and these two beams 19.2
The light reflected from the disk 0 is read out by the photodetector 9 in the same way as the light reflected from the read beam 18 from the disk.

In the photodetector 9, as shown in FIG.
The output T1 from the beam 20 and the output T2 from the beam 20 are detected separately, and after being amplified by the amplifiers 21 and 22, the difference between the two is determined by the difference circuit 23. In order to make this difference zero, the second mirror is 7 rotation device 24 is controlled.

When a control signal is applied to the rotation device 24, the second Mirror 7 rotates.

The output T1. of beams 19 and 20. The signal based on T2 is
As described above, it is used to control the second mirror 7, and is also used to control the readout beam 18 to scan in a spiral pattern.

The circuit branching downward in FIG. 4 is for spiral scanning, and when the output T1゜T2 signal passes through the low-pass filter 25, a large periodic displacement is detected, and this is detected by the amplifier. It is applied to the motor 27 via 26.

As a result, the optical system device 10 sequentially moves in the radial direction as the disk 1 rotates.

As a result, the readout beam 18 accurately scans the spiral track in which the pits are arranged, and one frame of information is read out in one round of scanning.

The above-described disk device and devices similar thereto have features such as high information density, inexpensive recording media, simple playback device, and ability to freely play back any desired location.

However, since a disk on which high-density recording is recorded is rotated at high speed for reproduction, there is a problem in that even a slight positional shift causes image distortion.

For example, if the center of the disk and the center of the shaft 3 of the motor 2 are even slightly deviated, the peripheral speed on the circumference around the center of the disk will differ depending on the location.

Therefore, in the case of concentric tracks, the circumferential speed differs depending on the location, and in the case of spiral tracks, the circumferential speed changes irregularly, and in both cases, ■ each horizontal scanning period in the field is different. It is also read out with a difference in one horizontal scanning period between the fixed number field and the even number field. Sometimes it was an image.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a disk drive device that can easily and accurately align the center of the disk with the center of the rotating shaft.

The present invention, which is a distant relative of the above object, is a device for rotationally driving a recording medium disk having a central hole, a rotating shaft having a conical inclined shaft portion that engages with the disk at the central hole; A turn having an annular protrusion for placing a disk at a position remote from the rotation axis, and the annular protrusion for placing a disk being provided with an elastic member so as to be elastically displaceable in the direction in which the rotation axis extends. a table; and a clamper having a disc pressing annular protrusion formed at a position away from the rotation axis to face the disc mounting annular protrusion of the turntable, and The diameter of the conically inclined shaft portion and the top surface position of the disk mounting annular projection are set so that the engagement position of the disk on the shaft substantially coincides with the top surface position of the disk mounting annular projection. , and the turntable and the clamper are configured to sandwich the disk between the disk mounting annular protrusion and the disk pressing annular protrusion. be.

According to the above invention, the height position of the disc can be changed within the range of elastic deformation of the elastic member constituting the annular projection for disc mounting.

Therefore, it is possible to change the engagement position of the disk with respect to the conical inclined shaft, and even if there is some variation in the size of the central hole of the disk, the function of the conical inclined shaft allows the disk to rotate with the center of the disk. It becomes possible to match the center of the axis.

Embodiments of the present invention will be described below based on the drawings.

FIG. 5 shows an embodiment of the present invention, and shows only a part of the disc playback device.

In this device, the center hole 3 of the video disc 31
The tip of the rotating shaft 33 for insertion into the rotary shaft 33 is not cylindrical but conical.

That is, a rotating shaft 33 corresponding to the shaft 3 in FIG.
A conical inclined shaft part 34 is provided at the tip of the disc 31, and the disc 31 is formed to engage with this conical inclined shaft part 34.

Further, a dish-shaped disk holding member, ie, a turntable 35, which has a substantially U-shaped cross section and a circular planar shape, is press-fitted into the rotating shaft 33 so as to rotate together with the rotary shaft 33.

This holding member 35 has an annular protrusion 36 for placing a disk.

Note that this annular protrusion 36 includes an elastic member 41.

Reference numeral 37 designates an upper holding member, ie, a clamper, which is shaped like an inverted version of the lower holding member 35, and has a disc pressing annular projection 38 including an elastic member 42 facing the disc mounting annular projection 36. .

The annular protrusion 38 of the upper holding member 37 is provided with a plurality of engagement protrusions 43, and the annular protrusion 3 of the lower holding member 35 is provided with a plurality of engagement protrusions 43.
6 is provided with a plurality of retaining holes 44 for receiving the protrusions 43.

Note that the disk 31 is also provided with a through hole 45 into which the engaging protrusion 43 is inserted.

A locking protrusion 39 is provided at the center of the upper holding member 37 as a connecting part.
is provided and is detachably inserted into a locking hole 40 provided at the tip of the rotating shaft 33.

As is clear from the drawings, the inclined shaft portion is arranged so that the position where the disk 31 is held in the inclined shaft portion 34 almost coincides with the position where the disk 31 is held between the lower annular protrusion 36 and the upper annular protrusion 38. 34 and the upper surface position of the disk-mounting annular protrusion 36 are determined.

In the disk drive device configured as described above, when mounting the disk 31, the video disk 31 is fitted onto the rotating shaft 33 with the upper holding member 37 removed, and the disk mounting including the elastic member 41 is performed. annular protrusion 36
Place the disk 31 on top of it.

As a result, the center of the inclined shaft portion 34 substantially coincides with the center of the central hole 32 of the disk 31.

However, as shown in FIG. 5, when the disk 31 is held between the lower holding member 35 and the upper holding member 37, the upper surface position of the disk mounting annular protrusion 36 and the engagement of the disk 31 with the inclined shaft portion 34 Since the positions are set to match, simply move the disc 31 to the lower annular protrusion 3.
6, the inclined shaft portion 34 and the disk 3
1 cannot be fully engaged.

After the disk 31 has been placed, the locking protrusion 39 of the upper holding member 37 is inserted into the locking hole 40 of the shaft 33 to be integrated with the shaft 33, and the lower surface of the annular protrusion 38 of the upper holding member 37 is inserted into the locking hole 40 of the shaft 33. is placed on the disk 31, and the disk 31 is held between the lower holding member 35 and the upper holding member 37.

At this time, if the upper holding member 37 is pushed down, the elastic member 4.
1 is elastically deformed, its upper surface position is lowered, and at the same time, the disk 31 is also lowered.

As a result, the central hole 32 of the disk 31 also has a tilted shaft portion 34.
, and reaches a fully engaged state.

Then, when a completely secured state is obtained, the upper holding member 3
Finish pressing 7.

After mounting the disk 31, if the rotary shaft 33 is rotated by a motor (not shown), the upper and lower holding members 35.3 are integrally attached to the shaft.
7 rotates, and the disk 31 held between the upper and lower holding members 35 and 37 also rotates together.

As is clear from the above, the disk mounting annular projection 36
It is possible to change the height of the disk 31 within the range in which the elastic member 41 is elastically deformed.

Therefore, if the disk 31 is a non-flexible disk and the size of the central hole 32 varies, the inclined shaft portion 34 and the disk 31 will not fit together within the range of elastic deformation of the elastic member 41. Changes in position are possible.

Thereby, even if the diameter of the central hole 32 changes somewhat, it is possible to make the center of the rotating shaft 33 and the center of the disk 31 substantially coincident.

Note that when the disk 31 has flexibility, the portion near the central hole 32 is bent to attach the disk 3 to the inclined shaft portion 34.
1, it is possible to make the center of the disk 31 coincide with the center of the rotating shaft 33 even if the diameter of the central hole 32 changes significantly compared to the case of a non-flexible disk. It becomes possible.

Although the present invention has been described above based on the embodiments, the present invention is not limited to the above-mentioned embodiments and can be further modified.

For example, the present invention can be applied to devices other than the device shown in FIG. 1, such as a device that scans a disk with a needle, and a device that uses both a needle and an optical system.

[Brief explanation of the drawing]

Fig. 1 is a schematic perspective view for explaining a video disc playback device, Fig. 2 is an explanatory diagram for explaining recording on the disc, Fig. 3 is a sectional view of the pit portion of the disc, and Fig. FIG. 1 is a circuit diagram for tracking in the apparatus shown in FIG. 1, and FIG. 5 is a sectional view of the rotating shaft and its vicinity showing an embodiment of the present invention. 31...disc, 32...center hole,
33... Rotating shaft, 34... Inclined shaft part,
35, 37... Holding member, 36, 38...
...Annular protrusion, 41.42...Elastic member.

Claims (1)

[Claims for Utility Model Registration] A device for rotationally driving a recording medium disk having a central hole, comprising: a rotating shaft having a conically inclined shaft portion that engages with the disk at the central hole; and a rotating shaft from the rotating shaft. a turntable having an annular protrusion for placing a disk at a remote position, the annular protrusion for placing a disk including an elastic member so that it can be elastically displaced in a direction in which the rotating shaft extends; a clamper having a disc pressing annular protrusion formed to face the disc mounting annular protrusion of the turntable at a position away from the rotation axis; The diameter of the conical inclined shaft portion and the upper surface position of the disk mounting annular projection are set so that the engagement position of the disk substantially coincides with the upper surface position of the disk mounting annular projection, and A disk drive device characterized in that the turntable and the clamper are configured so that the disk is held between the disk mounting annular protrusion and the disk pressing annular protrusion.