JPS61118609A - Apparatus for measuring non-spherical surface - Google Patents

Abstract

PURPOSE:To perform measurement with high accuracy, by such a simple structure that a slidable displacement detection apparatus is provided to the rocking arm attached to the highly accurate rotor provided to a base and calculating the position of a displacement detection apparatus on the rocking arm and the angle of the rotor. CONSTITUTION:The highly accurate rotor 2 provided to a base 1 is rotated by a motor 4 through a pulley 5 and a rotary angle is calculate from a rotary encoder 9. The shaking arm 6 horizontally rotated in integral relation to the rotor 2 is fixed to the rotor 2 and graduations 10 are provided to the rocking arm. A displacement detection apparatus 7 is slid on the rocking arm 6 along with a scale head 11 while contacted with the specimen 15 to be inspected held by a specimen holding member 14 and the the rotor 2 is rotated. The curve of the specimen 15 to be inspected in the plane as a displacement meter 8 by the value of the graduations 10 and the value from the rotary encoder 9. The height of the displacement meter 8 is successively changed to calculate the curve every time. By this method, the three-dimensional curved surface of a non-spherical surface can be calculated with high accuracy by a simple apparatus.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an aspheric surface measuring device for measuring the aspheric shape of a test sample.

2. Description of the Related Art Conventional aspherical surface measuring devices include systems that use optical interference fringes or holograms for optical measurements, and ultra-precision three-dimensional measuring machines for mechanical measurements.

Problems to be Solved by the Invention However, with the above-mentioned optical measurement method, if the amount of deviation from the reference spherical surface in the aspherical shape of the test sample becomes large, measurement becomes impossible, and the surface of the test sample is still rough. In some cases, there was a problem in that it was impossible to measure.

The above-mentioned ultra-precision three-dimensional measuring machine uses a laser length measuring machine for three-axis control, making it extremely expensive.

Therefore, the present invention enables highly accurate measurement even when the deviation amount of the test sample from the reference spherical surface is large, even when the surface of the test sample is rough, and has a simple structure and low cost. It is an object of the present invention to provide an aspheric surface measuring device that can reduce the .

Means to solve problems Technical point 3 of the present invention for solving the above problems.

Means 3) a base, a rotating body supported by the base so as to be able to rotate with high precision, and a drive device for rotating the rotating body; 2) a swinging arm attached to the rotating body; a displacement detection device supported so as to be linearly movable along the movable arm; a reading means for reading the rotation angle of the rotating body; and a reading means for reading the position of the displacement detection device at the swing arm. and a sample holding member that holds an aspherical test sample to be detected by the displacement detection device.

For production The effects of this technical means are as follows.

The displacement detection device is moved along the swinging arm, and while reading this position with the reading means, the distance between the center of the rotating body and the origin of the displacement detection device is set to be equal to the reference radius of curvature of the test sample. Next, the sample to be tested is held by the sample holding member. Next, the rotating body and the swinging arm are rotated, and the displacement detection device is moved to scan the surface of the test sample. Then, the aspherical shape of the test sample is measured from the reference radius of curvature, the deviation from the reference spherical surface obtained by the displacement detection device, and the rotation angle of the rotating body obtained by the reading means, that is, the movement angle of the displacement detection device. can do.

Embodiments Hereinafter, embodiments of the present invention will be described in detail based on the drawings. As shown in FIGS. 1 and 2, a rotary table 2 as a rotating body is rotatably supported by a support member 3 at the center of a base 1 with high precision.

The rotary table 2 is rotated by a drive device including a drive source 4 and a transmission mechanism 5 mounted on the base 1.

The central part of the swinging arm 6 is mounted on the rotary table 2 so that it can rotate together with the rotary table 2. A displacement detection device 7 is supported on the swing arm 6 so as to be movable linearly along the swing arm 6. This displacement detecting device 7 has a displacement gauge 8 incorporated therein. A rotary encoder 9, which is a reading means connected to the rotary table 2, is attached to the lower surface of the center of the base 1, and the rotary encoder 9 determines the rotation angle of the rotary table 2, that is, the movement angle of the displacement meter 8 of the displacement detection device 7. can be read. A linear scale 10 is attached to the side of the swinging arm 6 as a reading means for the 6th page position of the displacement detector 7, and a linear scale head 11 is attached to the side of the displacement detector 7.

These linear scales 10 and linear scale heads 11
The position of the displacement detection device 7 with respect to the swinging arm 6 can be read by this. Supports 12 are erected at both ends of the base 10, and a guide member 13 is horizontally installed between these supports 12. This guide member 13 includes a sample holding member 14.
is supported so as to be linearly movable along the guide member 13. A test sample 15 is removably held in the sample holding member 14 so as to face the displacement meter 8 .

Next, the operation of the above embodiment will be explained. The displacement detection device 7 is moved along the swinging arm 6, and while reading this position with the linear scale 10 and the linear scale head 11, the center position 16 of the rotary table 2 and the swinging arm 6 and the displacement meter 8 of the displacement detection device 7 are detected. This distance is set to be equal to the reference radius of curvature R of the test sample 150 (see FIG. 3). Next, the test sample 15 is held by the sample holding member 14, and
The sample holding member 14 is moved along the guide member 13 until the page test sample 16 contacts the displacement meter 8 and the read value on the displacement side 8 reaches zero. Next, the rotary table 2 and the swinging arm 6 are rotated by the driving of the drive source 4 via the power transmission mechanism 5, and accordingly the displacement meter 8 is moved along the reference spherical surface 17 as shown in FIG. This displacement meter 8 scans the surface of the test sample 15. Through this scanning, the deviation δ from the reference spherical surface 17 at the movement angle θ of the displacement meter 8 with respect to the test sample 15 having the reference radius of curvature R can be obtained from the output of the displacement meter 8. The movement angle θ of the displacement meter 8 can be obtained from the output of the rotary encoder 9 as the rotation angle θ of the rotary table 2. Therefore, the measurement results as shown in FIG. 4 can be obtained using the reference radius of curvature R9, the rotation angle θ, and the deviation δ.

As a result of the test, the aspherical shape of test sample 15 was 0.2
In the above embodiment, a half area 1 from the center point 16 in FIG.
In this case, the convex surface of the test sample can be measured (7 vane), and the concave surface of the test sample can be measured in the region (2) on the left half from the center point 16.

Note that the displacement meter 8 can measure the aspherical shape of the test sample 15 without contact by using a non-contact displacement meter.
At this time, as is clear from the above configuration, since the displacement meter 8 always faces in the normal direction to the sample surface, it is possible to eliminate errors due to the inclination of the sample surface, which is unique to non-contact displacement meters.

Effects of the Invention As is clear from the above explanation, according to the present invention, a displacement detection device is provided on the swinging arm that rotates together with the rotating body that rotates with high precision so as to be able to set the reference radius of curvature of the test sample. As the rotating body and swing arm rotate, the displacement detection device scans the aspherical surface of the sample held in the sample holding member, and the rotation angle of the rotating body and the position of the displacement detection device are read by the reading means. , the deviation of the aspherical surface is read by a displacement detection device. Therefore, even if the deviation amount of the aspherical surface is large, even if the surface of the test sample is rough, it can be measured with high accuracy.The trench structure is simple, so it is possible to reduce costs. can.

[Brief explanation of drawings]

Figures 1 to 4 show an embodiment of the aspherical surface measuring device of the present invention, with Figure 1 being a partially cutaway side view, Figure 2 being a partially cutaway plan view, and Figure 3 being a diagram explaining the measurement principle. , FIG. 4 is a diagram showing the measurement results. 1...Base, 2...Rotary table (rotating body)
, 4... Drive source, 6... Rocking arm, 7... Displacement detection device, 8... Displacement meter, 9... Rotary encoder (reading means) , 10... Linear scale (reading means), 11... Linear scale head (reading means), 13... Guide member, 14... Sample holding member, 15・・・・・・Test sample.

Claims (1)

[Claims] a base, a rotating body supported by the base so as to be able to rotate with high precision, and a drive device that rotates the rotating body;
a swinging arm attached to the rotating body; a displacement detecting device supported so as to be linearly movable along the swinging arm; a reading means for reading the rotation angle of the rotating body; An aspherical surface measuring device comprising: a reading means for reading a position on a swinging arm; and a sample holding member for holding an aspherical test sample to be detected by the displacement detecting device.