JPS60154356A - Recording device of master disc of optical disc - Google Patents

Abstract

PURPOSE:To improve the positioning precision in the radials direction by using pneumatic bearings as a rotating bearing of a disc and a moving guide fed in the radial direction by a screw. CONSTITUTION:A recording optical system is fixed, and a disc 22 is moved in the radial direction while rotating with respect to a recording lens, and information is recorded. A static pressure pneumatic bearing 21 which is not oscillated and can rotate with a high precision is used as the rotating bearing of the disc 22, and a shaft 24 is extended under the bearing 21 to fix a rotor 25 of a rotary motor, and a stator 26 is arranged. A balance weight 27 us provided near the motor. A disc rotating system constituted in this manner is buried in a block 29, and a straight going static pressure pneumatic bearing 30 is provided to hole the block 29, and the outside of a shaft 31 is moved in the radial direction of the disc. A pneumatic bearing is used as a thrust bearing 39 of a feed screw 32 driven by a motor 48. Thus, the positioning precision in the radial direction is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a master recording device for optical discs used for sound, image, computer memory, and the like.

[Background of the invention]

An optical disk master recording device coats a glass disk with photoresist, and while rotating it, irradiates it with a narrowly focused laser beam intermittently according to a modulated signal, thereby forming oval-shaped recesses called pits on the glass surface. This is a device that records signals such as , sound, 9 images, and computer recording. Since the actual disc is made into multiple replicas based on this master disc, the master disc is the most important one, and its recording device is a highly accurate mechanical device. In particular, with the recent increase in recording density, it has become necessary to increase the accuracy of circumferential position and narrow the bit interval in the radial direction, and high-definition recording technology has become more sophisticated.

The technology to achieve this mainly consists of technology to narrow and stably narrow the recording laser beam to submicron order, and technology to position the beam light and the recording position on the disk with submicron precision.

In this way, since it is sufficient that the recording laser position and the disk can be moved relative to each other, a fixed-disk moving type optical system is often used recently because it provides a stable optical system.

Conventionally, there was no device that required positioning accuracy on the order of submicrons, and the structure was as shown in FIG. First, the bearing 2 that supports the rotation of the disk 1.

A rolling bearing 3 such as a steel ball was used, and a rotary motor 4 attached to a separate shaft was connected via a pulley 5 and a belt 6. Furthermore, even if the motor is placed at the same time as the motor, the motor and the disk rotation shaft are connected by a coupling. The mechanism for moving the disk in the radial direction of the disk with respect to the recording lens uses a table 7 on which the spindle system is mounted as a rolling bearing of a steel ball or the like 9 in a V-groove 8, a movement guide 10, and is driven by a hole screw 11. The nut 12 of the ball screw was fixed to the side of the moving table and engaged with the ball screw. The bearing 13 of the ball screw is supported by an angular ball bearing and driven by a pulse motor or a step motor 14.

Since it had the above structure, it had the following drawbacks.

(1) Since the disk rotation motor and the rotating shaft are connected via a belt or a coupling, uneven rotation of the disk is likely to occur due to belt slippage, insufficient torsional rigidity of the coupling, etc.

(2) Since the feed screw of the movable base is mounted on the side, the movable base tends to yaw, making accurate positioning impossible.

(3) Both the rotating bearing part and the moving part have rolling elements (
(bearings, etc.), the vibrations inherent in these devices cannot be avoided, making it impossible to perform highly accurate positioning.

[Purpose of the invention]

It is an object of the present invention to provide an optical disk master recording device that does not have these drawbacks, that is, is capable of submicron positioning.

[Summary of the invention]

In order to achieve the above object, the present invention eliminates rolling elements (bearings, etc.) from the disk rotation system, the linear bearing of the moving table, the feed screw, and the bearing part of the feed screw.1.
Constructed with sliding bearings. In addition, the disk rotation motor is paired with the disk rotation shaft.

Furthermore, the feed screw of the moving table is a sliding screw that has been ground and lapped, and is placed at a position shifted in the direction of movement of the moving table on the extension line of the center of the disk, and connected using a special structure.

, [Embodiment of the Invention] An embodiment of the present invention will be described below with reference to FIGS. 2 and 3.

As the bearing for rotating the disk, a static air bearing 21, which is vibration-free and capable of high-precision rotation, was adopted.

The clearance between the hole diameter of the disk 22 and the rotating shaft 23 is set to almost zero, and the eccentricity of the outer diameter and hole diameter is made sufficiently small during manufacturing of the glass disk to prevent unbalanced forces caused by this. To ensure durability, consideration was given to bearing radial rigidity, etc. A shaft 24 is extended below the bearing, a rotor 25 of a rotary motor is fixed to the shaft, and a motor stator 26 is placed outside of the shaft, thereby eliminating couplings and belts, resulting in a so-called direct drive system. Furthermore, since the center of gravity of the disk and motor would be located quite high in this state, a balance weight 27 was provided near the motor to bring the center of gravity near the center of the air bearing. Furthermore, an encoder 28 for disk index and rotation control is attached to the lower end of the shaft. The rotating shaft and everything attached to it are installed after adjusting the dynamic balance, but ultimately the field balance is adjusted just before the disk is installed. Therefore, the remaining unbalance was caused only by the eccentricity of the outer diameter of the disk and the hole diameter, and was almost no problem.

These disk rotation systems are embedded in an aluminum block 29, and a straight hydrostatic air bearing 30 is provided outside the block at the height of the center of gravity so as to hold the block. The outside of the shaft 31 can be moved in the disk radial direction (screw arrangement direction). Also,
A feed screw 32 for movement is placed at the center of the disk at the same height, and its nut 33 is connected to the block by a V-shaped arm 34.The installation of this arm is also difficult due to the height and the moving object (rotating object). Considering the dynamic stability of the machine, the feed screw and nut are made of hardened steel and bearing metal in accordance with the above center of gravity, and after grinding the screw, sufficient screw wrap is applied to create a screw that can move very smoothly. used. With this Natsuto,
The connection with the arm is made in the direction of movement in order to eliminate the influence of the swinging of the nut mentioned above, which cannot be said to be completely eliminated, except for errors in the mounting direction of the disk linear guide (air bearing) and the feed screw (vertically, horizontally). Two pairs of hard and soft plate springs 35 are provided in the vertical and horizontal directions, and an intermediate holder 36 is provided.
connected via.

As for the bearings of the feed screw, the radial bearing 37 uses a glass fiber-containing resin plug 38, and the thrust bearing 39, which directly affects the radial positioning accuracy of the disk, uses an air bearing, and an oil damper 40 is also used. In addition, to remove backlash from screws and nuts that cannot be reduced to zero, a thin nylon string 41 is tied at the height of the axis of the nut, the direction is changed at right angles with a resin pulley 42, and a weight 43 is suspended in the direction of gravity. .

In addition, in order to eliminate instability caused by the movement (swaying) of this weight, an oil tank 45 is provided on the mounting base 44.
I tried to immerse myself in it.

The movable section planted in this way is connected to a motor 48 and a speed reduction mechanism 49 using precision gears, but it is also connected to a fast forwarding mechanism 50 in order to speed up the return process when not recording. There is.

As for the clutch used for this connection, a reverse action clutch 46 is used on the fine feed side to reduce the influence of energized heat due to the long recording time.

Further, a mirror 48 is attached to the block so as to constitute a laser interferometer whose optical axis 47 is at the same height as the recording surface of the disk.
2. [Effects of the Invention] This embodiment described in detail above has the following advantages.

(1) Rotation accuracy has improved.

(2) Yawing moth decreased.

(3) There is no vibration caused by rolling elements, etc., and quiet movement is now possible.

[0 Effects of the Invention] I. From the above, according to the present invention, the radial positioning accuracy and the like were improved, and a master recording device having submicron accuracy was obtained. The current accuracy is about 5% of the bit interval.

[Brief explanation of drawings]

FIG. 1 is a sketch showing a conventional structure, FIG. 2 is a sketch of a disk rotating portion in an embodiment of the present invention, and FIG. 3 is an overall view thereof. ■... Disc, 2... Rotating bearing, 4... Rotating motor, 10... Moving guide, 11... Ball screw,
14...Motor, 21...Rotating bearing, 22...Disk, 25...Motor rotor, 26...Motor stator, 27...Balance weight, 29...Block, 3o... Straight air bearing, 32... Feed screw, 33 River nut, 34... V-shaped arm, 35... Leaf spring, 37... Screw radial bearing, 39... Screw thrust bearing, 43... ...Backlash removal weight, 44...Base, 46...Clutch, 47...
・Optical axis, 48...Mirror, 49...Continued from page 1 Inside Kaio Research Institute

Claims (1)

[Claims] 1. Fix the recording optical system and set the recording lens position to
An optical disk master recording device of a type in which a disk made of glass or the like rotates and moves in the radial direction, characterized in that an air bearing is used for the rotation bearing of the disk and the moving guide that feeds the screw in the radial direction. Optical disk master recording device.