JPH01311210A - Measuring instrument for waving shape of disk surface - Google Patents

Abstract

PURPOSE:To easily and accurately measure the waving shape of the surface by detecting the rotational deflection of a mounting base for the disk and correcting the arithmetic result of a photodetecting element output arithmetic means. CONSTITUTION:A measurement sensor 7 irradiates the disk 1 which is rotated by a power source 3 with the laser light, whose reflected light is photodetected by the photodetecting element of the sensor 7. Then when the disk 1 rotates and a position different from an initial position is irradiated, a rotational deflection detecting means 11 detects the quantity of deflection. The output of the deflection detecting means 11 is applied to a position adjusting means 12 corresponding to the measurement sensor 7 and an output arithmetic means 13. Then the position adjusting means 12 corrects the position of the measurement sensor 7, i.e. the position on the disk 1 irradiated with the light so as to cancel the influence of the deflection of a disk rotating shaft 4. Further, the output arithmetic means 13 corrects a quantity based upon the deflection of the rotating shaft 4 as to the surface waving shape of the disk 1. Consequently, the accurate surface waving shape can be measured.

Description

[Detailed Description of the Invention] Summary] The present invention relates to a device for measuring the surface waviness shape of a rotating disk, which detects the rotational vibration of a mounting base on which the rotating disk is mounted, and calculates the calculation result of the light receiving element output calculation means. By correcting
The purpose of the present invention is to provide a simple and accurate device for measuring the shape of surface waviness, and the device detects the reflected light of a light beam irradiated onto a rotating disk using a light receiving element to inspect the shape of waviness on the surface of the disk. A detection means for detecting the rotational deflection of a disk mounting base mounted on a rotating disk and mounted on a rotating shaft driven by a power source, a means for adjusting the position of a light beam generation source, and a light receiving element output calculation for reflected light from the disk. and controlling the position adjustment means of the light beam generation source using the output of the rotational shake detection means, and correcting the calculation result of the reflected light receiving element output calculation means to measure the waviness shape of the disk surface. Configure.

[Industrial Application Field] The present invention relates to an apparatus for measuring surface waviness shape values of a rotating disk.

Conventionally, laser light is irradiated onto the surface of a rotating magnetic disk.
The undulation shape was calculated by calculating the inclination data of each point on the disk surface, which was obtained by receiving the reflected light with a light-receiving element. In this non-contact method of inspecting the fine undulations on the disk surface, any wobbling of the shaft that rotates the disk directly leads to measurement errors, and errors cannot be avoided unless expensive equipment is used. Therefore, there was a need to develop a technique to obtain error-free shape values using relatively simple means.

[Prior Art] An apparatus for mounting a magnetic disk on a mounting table and measuring the shape of surface waviness has a configuration shown in FIG. 4. In Fig. 4, 1 is a disk, 2 is a mounting base, 3 is a motor as a power source for rotating the disk, 4 is a rotating shaft, 5 is a spindle, 6 is a bearing, and 7 is a surface waviness shape measurement using a laser beam. A sensor, 8 a sensor movement control section, and 9 a measured value calculation control section. In FIG. 4, a rotary shaft 4 rotates the mounting base 2 by a motor 3 via a spindle portion 5. As shown in FIG. A disk 1 is placed on a mounting base 2, and the disk 1 may have slight undulations on its surface when rotated. Initial settings are made such that a laser beam is irradiated from the measurement sensor 7 to a point on the disk 1, and the reflected light is made to enter, for example, the center of a four-division light-receiving element. If there are undulations on the surface at other measurement points on the disk I, the reflected laser light will reach other positions on the light receiving element. The magnitude of the tilt angle of one surface of the disk is calculated and determined from the distance between the reflected light arrival points and the distance between the sensor and the disk. and measurement sensor 7
If, for example, the irradiation position is set at a number of points along the circumference of the disk 1 while being moved by the sensor movement control unit 8, a large number of data along the circumference of the disk surface will be obtained. The arithmetic control unit 9 can calculate the undulation shape.

[Problems to be Solved by the Invention] The rotating shaft 4 of the motor 3 is prone to wobbling during use. That is, as shown in FIG. 5A with a partial cross section of the bearing, the hair rings 6-1 and 6-2 are pressed against the shaft 4 and tightened with the band 6-5, but the hair rings 6-L and 6-2 are tightened with the band 6-5.
2 wear and band 6-3 tightening due to changes in force, etc.
The center line of the shaft 4 rotates while being tilted. Therefore, when looking at the rotation trajectory of one point on the outer peripheral surface of the rotating shaft 4,
The result is as shown in FIG. 5B. Now, when the rotating shaft 4 is rotating while causing shaft wobbling, a point on the surface of the mounted disk 1 also moves wobbling in response to the rotational wobbling. Therefore, even if the beam irradiation light is irradiated on the circumference of a predetermined radius from the center of the rotation axis, data on the reflected light is obtained by irradiating the surface of the disk at a place other than the circumference.
The obtained undulation shape is not an accurate value. For example 5.25
When irradiating a laser beam onto an inch magnetic disk,
The beam diameter was about 50 μm, and the movement of the irradiation point on the disk surface due to the vibration of the rotation axis was several μm or more.

Therefore, if the distance between the bearings 6-1 and 6-2 is extended over a long period of time, the vibration will be reduced, but the device will become larger and the power of the motor will need to be increased.

On the other hand, it is also possible to use an air bearing or other structure that does not wear out during rotation without using a normal bearing, but this has the drawback of making the device extremely expensive.

The purpose of the present invention is to improve the above-mentioned drawbacks and measure the surface waviness shape easily and accurately by detecting the rotational shake of the mounting base on which the rotating disk is mounted and correcting the calculation result of the light receiving element output calculation means. The goal is to provide equipment.

[Means for Solving the Problems] FIG. 1 is a diagram showing the basic configuration of the present invention. In FIG. 1, 1 is a disk, 2 is a mounting base, 3 is a power source for a rotating shaft, 4 is a rotating shaft, 7 is a surface waviness shape measurement sensor including a light source and a light receiving element, 11 is a rotational shake detection means, and 12 is a A position adjustment means for a light beam generation source, and a reference numeral 13 denotes a light receiving element output calculation means.

The present invention has the following configuration in an apparatus for inspecting the shape of waviness on the surface of the disk 1 by receiving the reflected light of the light beam irradiated onto the rotating disk 1 by the light receiving element 7. That is, a rotating shaft 4 mounted with a rotating disk 1 and driven by a power source 3
a detection means 11 for detecting the rotational shake of the disk mounting base 2 which is pivotally attached to the disk mounting base 2; a position adjustment means 12 for the light beam generation source;
A light beam receiving element output calculating means 13 for reflected light from the disk 1 is provided, and the position adjusting means 12 of the light beam generation source is controlled by the output of the rotational shake detecting means 11, and the calculation means 13 for calculating the output of the reflected light receiving element is controlled. The method is to correct the results and measure the disk surface waviness shape value.

[Operation] In the configuration shown in FIG. 1, the rotating shaft 4 is rotated by the power source 3. Since the rotating shaft 4 and the mounting base 2 are fixed with a screw or the like, and the disk 1 is placed on the mounting base 2, the disk 1 is rotated by the power source 3. For example, a laser beam is irradiated onto the disk l from the measurement sensor 7, and the reflected light is sent to the sensor 7.
The light is received by the light receiving element inside. When the disk 1 rotates and irradiates a position different from the initial position, the position of the incident light on the light receiving element is also different from the initial position, and the interval corresponds to the waviness of the disk 1, so that the waviness shape value can be measured.

At this time, since the rotating shaft 4 that rotates the disk 1 has rotational wobbling due to aging of the bearings, etc., the amount of wobbling is detected by the rotational wobbling detection means 11. The output of the blur detection means 11 is applied to a position adjustment means 12 corresponding to the measurement sensor 7 and an output calculation means 13, and the former determines the position of the measurement sensor 7, that is, the irradiation position of the light irradiated onto the disk l, according to the disk rotation axis. Correct to cancel the effect of blur in 4. In addition, the output calculation means 13 corrects the amount based on the wobbling of the rotating shaft 4 for the surface waviness of the disk 1 measured by the measurement sensor 7.

[Embodiment] FIG. 2 is a diagram showing the configuration of the rotational shake detection section in FIG. 1 as an embodiment of the present invention. FIG. 2A shows a perspective view, and FIG. 2B shows a top view. Figure 2A.

In B, 14 is a light source using a semiconductor laser, 15
1 is a light focusing lens, and 16 is a two-dimensional position detection element.

The disk mounting stand 2 is sufficiently polished to improve the reflection of light. As shown in FIG. 2B, when the side position of the mounting base 2 is indicated by the solid line and when it is indicated by the broken line due to rotational shake, the light incident position on the two-dimensional position detection element 16 changes, and the position changes. -ffi corresponds to the magnitude of blur. (Here, this method is named the triangulation method.) Then, the two-dimensional position detection element 16 obtains vertical tilt information (face tilt information) and horizontal distance change information of the mounting base 2. In particular, the tilt information is applied to the output calculation means 13 so as to correct the disk surface waviness shape value,
The distance change information is applied to the position adjustment means 12 for position correction of the measurement sensor.

In addition to the ones shown in the figure, the rotational shake detection unit is a capacitive type,
It can also be configured as a fiber reflection type.

Now, when the distance from the surface of the mounting base 2 to the light emitting source 14 is R8, the distance change information of ΔR is obtained, and the position of the disk surface at a distance r from the rotation axis center is sensed, the position correction amount is ΔR -r/R.

This correction is performed by correcting the position of the position movement motor for the measurement sensor, or by performing fine adjustment using a piezoelectric element.

FIG. 3 shows a block section showing the above-mentioned configuration, and the blur detection output is given to the drive motor 18 via the amplification section 17. The drive motor is an example of the position adjustment section 12. In addition, 19
indicates a rotary encoder, and since information on the rotational position of the disk I is obtained from the encoder 19 for measurement by the waviness measurement sensor, the inclination information can be corrected more accurately by obtaining this information.

The rotating disk is preferably a magnetic disk, but is not limited thereto, and can also be applied to a semiconductor wafer.

[Effects of the Invention] Thus, according to the present invention, it is constructed using a relatively inexpensive part (A, and in particular, by providing a blurring detection part to detect the blurring that occurs in the rotation axis, Since the measured values are corrected, accurate values for the undulation shape can be calculated.

[Brief explanation of the drawing]

Fig. 1 is a diagram showing the principle configuration of the present invention, Figs. 2 and 3 are diagrams showing the configuration of an embodiment of the invention, and Fig. 4
This figure shows a conventional measuring device, and FIG. 5 is a diagram for explaining the deviation of the rotation axis in FIG. 4. 1--Rotating disk 2--Disk mounting stand 3--Power source 4--Rotating shaft 7--Waviness shape measurement sensor 11 including a light receiving element
One-rotation shake detection means 12 - Position adjustment means 13 - Output calculation means Patent applicant: Fujitsu Limited Agent Patent attorney Eisuke Suzuki B S a: Figure 2 y5 d i = - Ikuri Figure 3 Conventional bereaved family Σ Figure 4 "Axis selection A B Figure 5

Claims (1)

[Claims] I. The light receiving element (7) receives the reflected light of the light beam irradiated on the rotating disk (1), and the disk (1)
In a device that inspects the shape of surface waviness, detection detects rotational vibration of a disk mounting base (2) mounted on a rotating disk (1) and attached to a rotating shaft (4) driven by a power source (3). means (11), position adjustment means (12) for the light beam generation source, and a disk (
1), the output of the rotational shake detection means (11) controls the position adjustment means (12) of the light beam generation source, and the output of the reflected light receiving element A disk surface waviness shape measuring device characterized in that the calculation result of the output calculation means (13) is corrected to measure the disk surface waviness shape. II. The detection means for detecting rotational shake recited in claim I is characterized in that it is of a triangulation type that measures the reflected light when light is applied to the side surface of the mounting base, which has good light reflectance. Disc surface waviness measurement device.