JPH04157310A - Measuring apparatus of shape of disk - Google Patents

Abstract

PURPOSE:To measure the shape of a peripheral edge part of a hole with high accuracy by levitating a disk by air, rotating a noncontacting displacement sensor provided at the center of the disk, and measuring the inner peripheral part of the disk. CONSTITUTION:An air stage 5 provided to levitate a disk 1 has a minute hole 6 and an air inlet 7. Compressed air is sent into the stage 5 and discharged out from the minute hole 6. Therefore, owing to the discharged air, the disk 1 on the stage 5 levitates at a position where it balances with its own weight. A noncontacting displacement sensor is used to measure the shape of the disk. Sensors 2, 3 are provided in the peripheral edge part of the disk hole with the disk 1 held therebetween. Moreover, since the sensors 2, 3 have stages 8, 9 which move the respective sensors up and down minutely, and a moving stage 14 for moving the sensors in a horizontal direction, the sensors 2, 3 can be positioned to the floating disk 1. Accordingly, the data in a peripheral direction of the inner peripheral part of the hole of the disk 1 is measured, and the shape of the peripheral edge part of the hole can be measured with high accuracy.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an apparatus for measuring and evaluating the shape accuracy of a disk having a hole in the center, particularly at the inner circumference of the disk.

[Conventional technology]

Disks, which are the media for optical disk devices and magnetic disk devices, and silicon wafers, which are the raw material for semiconductor devices, are subject to individual product flatness, warpage, and distortion during their production and management processes.
Quality such as thickness is strictly inspected. As these inspection means, there is an evaluation device as shown in FIG. This is an example of an accuracy measurement/evaluation device for discs.

In FIG. 1, a disk 1 is fixed by a disk clamp mechanism 20 at its central portion on a disk drive shaft 21 by suction or compression using a screw or the like. The clamped disk 1 is rotated by a disk drive motor 22. A non-contact displacement meter is used to measure the shape accuracy of the disk 1. For example, a sensor 2. sensor 3
The disks 1 are sandwiched facing each other on the same radius as shown in FIG. The magnitude of the waviness on the top and bottom surfaces is measured from the outputs A and B from the amplifier, and the sensor is moved from the outer circumferential side to the inner circumferential side.
By measuring, it is possible to understand the waviness of the entire disk under clamped conditions. There are various types of disks, such as conductors, semiconductors, and insulators, and capacitive displacement meters are generally used as sensors because of the need to measure a wide range of objects and to measure with high precision. Find addition and subtraction of outputs A and H,
By determining the difference from the initial value, the thickness of the disk and the thickness deviation from the reference value can be determined.

As described above, as represented by the configuration shown in Figure 2, the disk shape (static data) in the disk tightened state (when the device is in use) is determined,
Furthermore, the conventional technology was to obtain the disk dynamic characteristics (dynamic data) by rotating the disk at the actual operating speed, and the evaluation device mainly measures the media zone of a perforated disk. It is.

[Problem to be solved by the invention]

The above-mentioned conventional technology is configured mainly for the purpose of measuring and evaluating the area where information is written (media zone). This is because, as shown in FIG. 1, this type of disk is clamped by mechanically applying pressure to the peripheral edge of the central hole, so that the disk clamping surface is hidden. Therefore, the measurement range is limited to areas other than this zone, and furthermore, the evaluation is limited to this zone because of the need to ensure the accuracy of the media section.

However, the shape of the disk after clamping is greatly influenced by the initial surface accuracy of the clamped part.

In order to ensure the quietness required of disks stacked in recent high-density, high-precision, low-flying magnetic disk drives, etc., precision control of the clamping surface is an unavoidable issue. Therefore, with the conventional technology, accuracy control in this area has not been possible, and the overall accuracy of one disk surface has not been evaluated.

The purpose of the present invention is to
The aim is to measure and evaluate the shape accuracy of the disc, and also to support the disc by air levitation, without damaging the disc.
An object of the present invention is to provide a measurement/evaluation device that can measure the shape of the peripheral edge of a hole with high precision.

[Means to solve the problem]

In order to achieve the above object, the present invention has devised an apparatus in which a single disc is floated in air without being clamped, and the shape of the peripheral edge of the disc hole can be measured in this state.

〔Example〕

FIG. 1 shows an embodiment of the present invention. In order to levitate the disc 1, an air stage 5 is arranged and the disc 1 is closely stacked on the base 13. Air stage 5 has micro holes 6. An air intake lower is provided, and compressed air enters the stage through the air intake lower and is discharged from the microholes 6. Therefore, the disc 1 on the air stage 5 is floated by the discharged air at a position balanced with the disc's own weight. Since the disk 1 does not come to rest but shifts in the radial direction while floating, a disk stopper 4 for stopping the disk 1 is provided on the air stage 5.

A non-contact displacement meter is used for shape measurement, and sensor 2. sensor 3
is placed around the circumferential edge of the disc hole, sandwiching the disc.

The sensor has a sensor vertical fine movement table 8, 9 sensor horizontal movement table 1
4, which enables positioning of the sensors 2 and 3 with respect to the disk 1 during levitation. After the 0 positioning, a drive motor 10 is disposed on the base 13, and a motor shaft 11. When the sensor stage 12 is rotated, the sensor on the stage rotates, and the circumferential direction data of the inner circumferential portion can be measured.The data was described in the conventional example shown in FIG. 1. undulation,
It is possible to evaluate plate thickness and deviation.

FIG. 3 is a front view of the air stage 5. In order to levitate the disk, a plurality of micro holes 6 are formed at equal intervals.

FIG. 4 shows a third embodiment as a partial sectional view. The sensors 2 and 3 have a structure that allows them to move in the radial direction on the sensor stage 12. Therefore, sensor 2
, 3 retreat toward the center of the disk from the inner edge of the disk 1, the disk 1 is pulled from the disk device position B to the disk removal position A without touching the sensors 2 and 3. It is possible to separate it.

FIG. 5 is a front view of FIG. 4 seen from directly above.

The sensor 2 is normally in the sensor retracted position D. During measurement, the sensor is set on the inner edge of the disk C.

FIG. 6 shows an example in which O-rings 14 and 15 are arranged on the outer diameter side and the inner diameter side, respectively, on the contact surface with the base 13 in order to prevent leakage of compressed air inside the air stage 6. By preventing air leakage, it becomes possible to keep the disk floating in a more stable position.

In addition to the structure shown in FIG. 2, FIG. 7 shows a structure in which a tilting table 13 is arranged below the base 13. Since the sensors 2 and 3 and the disk 1 are tilted at the same time, their parallelism is maintained. By further tilting the disk 1, the disk 1 generates a pressing force toward the lower side of the slope due to its own weight, and therefore,
It comes into contact with the disk stopper 4 and becomes stable. FIG. 8 is a front view of FIG. 7 seen from the disk side. Since a pressing force is generated due to its own weight, only two disc stoppers 4 are required.

FIG. 9 shows an example of the present invention having a tilting table.
This is what is shown. A motor 19 is fixed to the air stage 5, and a drive roller 18 is attached to the motor 19. The drive roller 18 has a structure that allows the disc 1 to be rotated by frictional force via the driven roller 17. FIG. 1o is a front view of FIG. 9 viewed from above. Since it is tilted, the disc 1 comes into contact with the driven roller 17 due to its own weight. If the two driven rollers 17 are rotated in the circumferential direction, the disc 1
can be rotated in the direction of the arrow in FIG. 10, allowing the sensor 2 to measure the shape of the peripheral edge of the hole.

FIG. 11 shows another embodiment of the invention. Figure 9.

In the embodiment shown in FIG. 10, the disc 1 is driven by a roller, and the rotation accuracy of the disc 1 is the radial of the roller.

It depends on the rotation accuracy in both thrust directions. On the other hand, disk 1
Since the structure is such that the discharge air is provided with a flotation blade and balanced with the disc's own weight, the air splash characteristics in the flotation direction become non-linear, and the spring stiffness becomes weaker in the direction of increasing flotation. It has a mobility that increases the variation in flying height when a force that causes disturbance is applied in the thrust direction by the rollers. The embodiment shown in FIG. 11 is intended to assist in achieving the above characteristics. A nozzle 23 is arranged on the upper surface of the disk 1 to blow compressed air onto the upper surface of the disk 1. As a result, the disk 1 is pressed against the air stage 5 side, the stiffness of the air spring on the upper surface of the disk 1 increases, and the roller 17
Fluctuations in the flying height of the disk 1 can be suppressed even if an external force in the flying direction is applied. Therefore, when measuring the shape of the inner circumferential portion of one disk, there is little disk fluctuation and the disk floats at a stable position, which has the advantage of improving measurement accuracy.

FIG. 12 is an example of a structure that takes into account the workability of disc replacement. A plurality of nozzles 23 having air discharge holes are arranged at equal intervals on the circumference. The nozzle 23 is rotatably supported by a nozzle rotation shaft 24. The nozzle 23 rotates from the nozzle set position WE to the nozzle retreat position F. Since the sensor 2 is also movable within the hole of the disk 1 in the disk radial direction, the nozzle 23. If the sensors 2 are placed in their respective retracted positions, the disk 1 can be attached and detached on the air table 5.

It should be noted that the air levitation mechanism, which is a feature of the present invention, must be provided and configured so as to eliminate pressure fluctuations as much as possible, suppress fluctuations in the flying height of the disk, and avoid measurement errors when measuring the circumference. In addition, in order to blow air onto the surface of the disk, which is the media, it is necessary to use as clean air as possible. Although not shown in this structural diagram example, in view of this necessity, a precision pressure regulating valve, a large-capacity air tank, and a highly efficient dust removal filter are separately required to be installed.

〔Effect of the invention〕

According to the present invention, it is possible to measure the shape of the peripheral edge of the central hole of a disk with high precision and without contact, which was impossible to measure with conventional techniques, and the disk itself is also floated with air. Therefore, it is possible to provide an extremely reliable evaluation device without damage to the disk surface.

Further, by using a structure in which the entire sensor body and air stage are tilted, the weight of the disc itself can be utilized, which is effective in reducing the number of disc stoppers to be arranged.

In addition, there is also a structure in which the sensor body is placed in the center hole of the disk and the sensor itself is rotated to measure the peripheral edge of the disk hole.Conversely, the sensor side is fixed and the floating disk is rotated by a drive roller, etc. It is also possible to provide a structure in which the peripheral edge of the disc hole is also measured.

Furthermore, by using a structure that blows air out from the top of the disc, the air spring rigidity on both sides of the disc becomes stronger.

Fluctuations in the flying height of the disk can be reduced.

[Brief explanation of the drawing]

Fig. 1 is a longitudinal sectional view of an embodiment of the present invention, Fig. 2 is a measurement block diagram of a conventional disk shape measuring device, Fig. 3 is a front view of the air stage of the present invention, and Fig. 4 is a main FIG. 5 is a front view of the embodiment showing the arrangement of the stopper for stopping the disk; FIG. 6 is a partial cross-sectional view showing the disc mounting operation according to the invention; FIG. 6 is a diagram showing the prevention of leakage from the air stage according to the invention. FIGS. 7 and 8 are longitudinal cross-sectional views and disk front views of an embodiment using an inclined direction, and FIGS. 9 and 10 are longitudinal cross-sectional views showing an embodiment using a disk drive method, and FIGS. Disc front view, Figures 11 and 12
The figures are a longitudinal sectional view and a front view of the disk, showing an embodiment in which an air jet nozzle is provided on the upper surface of the disk. 1... Disc, 2, 3... Non-contact sensor, 4... Disc stopper, 5... Air stage, 6... Microhole, 7... Air intake, 8, 9 ...sensor vertical fine movement table, 10...drive motor, 12...sensor stage,
13... Base, 16... Inclined table, 17... Followed roller, 19... Motor, 23... Nozzle.

Claims (1)

[Claims] 1. In an apparatus for measuring the surface shape of the inner peripheral side of a disk having a hole in the center using a non-contact displacement meter, the disk is floated by air and placed at the center position of the disk. A disk shape measuring device characterized in that the shape and thickness of the inner circumferential portion of the disk can be measured by rotationally moving a non-contact displacement meter.