JPH03251708A - Shape measuring apparatus for parabolic antenna surface - Google Patents

Abstract

PURPOSE:To measure a surface shape from values of moving mechanism as given when a difference between outputs of two CCDs in down to zero by a method wherein a laser light is made parallel to be focused onto the surface to be measured and the reflected light thereof is divided in two to be incident into the two CCDs, the one arranged roughly before the focus of one lens and the other roughly after the focus of the other lens. CONSTITUTION:A laser light is made incident onto a surface to be measured through a converging lens 5 and the reflected laser light thereof is divided in two to be incident into two CCD sensors 9 and 10 through lenses 7 and 8. Here, the CCD sensors 9 and 10 are so arranged that the one thereof is before a focal length of one lens and the other after the focal length of the other lens. Then, outputs of output circuits 11 and 12 are inputted into a differential amplifier 13. Now, when a moving mechanism 21 of a detector section is moved and a distance between the converging lens 5 and the surface to be measured reaches the focal length, an output of a differential amplification circuit 13 is down to zero. In this manner, a moving mechanism 19 and a rotation mechanism 20 are moved with a control section 21 thereby enabling the measuring of a shape of the surface to be measured from a moving value thereof.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a parabolic antenna surface shape measuring device, and particularly to a parabolic antenna surface shape measuring device for measuring the surface shape of a parabolic antenna in a non-contact manner during assembly or inspection of the parabolic antenna. Concerning a measuring device.

[Conventional technology]

A measurement jig 26 has several electric micrometers 25 arranged on the theoretical parabolic curve of the plane of the parabolic antenna 1 in a direction that hits the parabolic surface of the parabolic antenna 1, and this measurement jig 26 is set as a reference axis. a jig moving mechanism 27 that moves the measurement jig in the direction; a rotation mechanism 28 that rotates the measurement jig about the reference axis; and a setting jig 24 that holds the parabolic surface of the parabolic antenna 1 and can manually adjust its posture. It consists of:

The parabolic antenna 1 is set on the setting jig 24 with the parabolic surface facing upward. A plurality of electric micrometers 25 are arranged at equal intervals on the outside of a half-piece type measuring jig 26 whose outer shape matches the shape of the parabolic surface of the parabolic antenna 1 so that the tips are aligned on the theoretical parabolic curve of the parabolic antenna 1. , are placed outward at right angles to the tangent direction of the parabolic curve.

The measuring jig 26 is moved by the jig moving mechanism 27 and the electric micrometer 25 is applied to the parabolic antenna 1 so that the measured values of two at both ends of the plurality of electric micrometers 25 become 0. Manually adjust the attitude of the parabolic antenna 1, read the remaining electric micrometer value, and record it.

Next, the measuring jig 26 was rotated by the rotating mechanism 28, and the values of the electric micrometer 25 were read at a plurality of rotational positions to perform measurements.

[Problem to be solved by the invention]

With the conventional parabolic antenna surface shape measuring device described above, depending on the shape of the parabolic antenna surface and the shape of the electric micrometer probe, the contact point of the probe may differ from the point to be measured, as shown in Figure 8. The error in the value becomes large.

Moreover, the measured value is only the displacement amount of the directional component that can be measured by the electric micrometer, and the value of the inclination at each measurement point cannot be measured.

In addition, if the size or shape of the parabolic antennas to be measured differs, measurement jigs for each type will be required for each type of parabolic antenna, making it difficult to manufacture, store, and control the accuracy of the measurement jigs. there were.

[Means to solve the problem]

The parabolic antenna surface shape measuring device of the present invention includes a laser as a light source, a collimator lens that makes the laser light emitted from the laser nearly parallel light, and a collimator lens that converges the emitted laser light that is made nearly parallel light on the surface to be measured. 1 converging lens,
a first mirror that divides the emitted laser beam into two, reflects the reflected laser beam on the surface to be measured, and separates the reflected laser beam that passes through the first converging lens from the emitted laser beam; and the separated reflected laser beam; a beam splitter that separates the laser beam into two, second and third converging lenses that respectively converge the two divided laser beams, one of the focal points of the converged laser beam is located immediately before, and the other is located immediately after, and two one-dimensional CCD sensors arranged perpendicular to the optical axis, two output circuits that output an output proportional to the spot diameter on each one-dimensional CCD sensor, and a difference between the outputs of the output circuits. a distance detecting section composed of a dynamic amplification circuit; a second mirror that obliquely irradiates and reflects the emitted laser light that is divided by the first mirror and does not pass through the first converging lens onto the surface to be measured; an angle detecting section that includes a position detector that detects the position of the reflected laser beam that is irradiated onto the surface to be measured and reflected by the second mirror; and an antenna holding section that holds a parabolic antenna that is the object to be measured; A reference axis with respect to the plane defined by the antenna holding section, a detection section movement function that holds the distance detection section and moves it in a direction parallel to the reference axis, and a detection section movement function that has the function of holding the distance detection section and moving it in a direction parallel to the reference axis. It is configured to include a rotation function for rotating on a plane perpendicular to the reference axis around the reference axis, and a control section for controlling each of the sections.

〔Example〕

Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram showing an embodiment of the present invention. FIG. 2 is a detailed diagram of the distance detection mechanism 14 of FIG. 1. Figure 1,
In FIG. 2, one embodiment of the present invention is a parabolic antenna surface shape measuring device for measuring the surface shape of a parabolic antenna, which includes a laser 2 as a light source, a collimator lens 3, a half mirror 4, etc., a converging lens 5, Beam splitter 6
, converging lenses 7 and 8, and two one-dimensional CCD sensors 9 and 10, one of which is located immediately in front of the converged laser beam and the other is located immediately after, and which are arranged perpendicular to the optical axis. Two output circuits 11 and 12 that output an output proportional to the spot diameter on the one-dimensional CCD sensor, and a differential amplifier circuit 13 that detects the difference between the outputs of the output circuits 11 and 12.
An angle detection section 18 consisting of a mirror 15, a converging lens 16, and a position detector 17, and an antenna holding section 19 that holds a parabolic antenna as an object to be measured. , a reference axis 20 for the plane defined by the antenna holding part, a detection part movement function 21 having a function of holding the distance detection part 14 and moving it in a direction parallel to the reference axis, and the detection part movement function. a rotation function 22 that rotates around a reference axis on a plane perpendicular to the reference axis;
It is composed of a control section 23 that controls each section.

If the distance between the light source laser 2 and the collimator lens 3 is set equal to the focal length of the collimator lens 3, then
The emitted laser light emitted from the laser 2 passes through the collimator lens 3 and becomes parallel light. The output laser beam, which has been made into a parallel beam, is split into two by a half mirror 4, and the output laser beam that has passed through the parallel beam is converged onto the surface to be measured by the converging lens 5, and is reflected on the surface to be measured.

The reflected laser beam reflected on the surface to be measured passes through the converging lens 5 again.
The beam passes through the beam, enters the half mirror 4, and is split into two.

The reflected laser beam is separated from the incident laser beam by the half mirror 4, enters the beam splitter 6, and is split into two beams. The reflected laser light that has passed through the beam splitter 6 and gone straight passes through a converging lens 7 and is converged. The focused reflected laser beam is passed through a one-dimensional CCD placed perpendicular to the optical axis of the reflected laser beam.
The output circuit 11 outputs an output proportional to the spot diameter of the reflected laser beam that is incident on the sensor 9 . Here, let A be the distance from the second principal point of the converging lens 7 to the one-dimensional CCD sensor 9.

The reflected laser light whose optical axis has been changed after passing through the beam splitter 6 passes through the converging lens 7 and is converged in the same way as the reflected laser light that has traveled straight. The converged reflected laser beam enters a one-dimensional CCD sensor 10 placed perpendicular to the optical axis of the reflected laser beam, and an output circuit 12 outputs an output proportional to the spot diameter of the incident laser beam. The differential amplifier circuit 13 amplifies and outputs the difference between the outputs of the output circuit 11 and the output circuit 12. Here, the distance from the converging lens 8 to the one-dimensional CCD sensor 10 is assumed to be B.

The same lens is used for the converging lens 5, the converging lens 7, and the converging lens 8, and the focal length of the rear side is F.

Here, the relationship between distances A and H is set as follows.

A=F+dX (a) Equation B=F-dX (b) Equation Now let the distance between the converging lens 5 and the surface to be measured be S, and move the distance detection section 14 parallel to the reference axis 19 using the detection section moving device 120. When S=F, the emitted laser beam converged by the converging lens 5 is focused on the surface to be measured. At this time, the reflected laser light reflected from the surface to be measured becomes parallel light after passing through the converging lens 7.

When the reflected laser light that has become parallel light enters the converging lens 7 and the converging lens 8, it is focused at the position of the rear focal length F of each. At this time, if the output of the output circuit 11 is plotted on the vertical axis and the moving distance of the detecting section moving mechanism 21 is plotted on the horizontal axis, it becomes a graph as shown in FIG. When plotted on the horizontal axis and graphed, the fifth
It becomes a diagram. If you plot the output of the differential amplifier circuit 13 on the vertical axis and the moving distance of the detection unit moving mechanism 21 on the horizontal axis, you will get a curve like that shown in Figure 6, which is the difference between Figures 4 and 5. Equivalent to.

Since the shape of the laser beam is symmetrical at the focal point, when the detection unit moving mechanism 21 is moved, when the distance between the converging lens 5 and the surface to be measured becomes equal to F, the one-dimensional line sensor 9
The diameters of the reflected laser beams incident on the one-dimensional line sensor 10 and the one-dimensional line sensor 10 are equal.

In other words, the value on the horizontal axis when the values on the vertical axis in FIGS. 3 and 4 are equal corresponds to when the distance between the converging lens 5 and the surface to be measured is equal to F. Since FIG. 6 corresponds to the difference between FIG. 4 and FIG. 5, the output of the differential amplifier circuit becomes zero at this time.

In this way, when the value of the output of the differential amplifier circuit 14 is O, the distance between the converging lens 5 and the surface to be measured is equal to the focal length F of the converging lens 5.

At this time, the position where the emitted laser beam that has passed through the converging lens 5 is reflected on the surface to be measured is the measurement point. The position of the mirror 15 is set so that the output laser beam reflected by the mirror 15 comes to the measurement point.The reflected laser beam is reflected by the mirror 15 and converged by the converging lens 16, and the reflected laser beam reflected by the measurement point on the measurement surface is The light enters the position detector 17.

When the incident position of the position detector 17 is known, the distance between each component of the position detection unit is detected, and the distance between the converging lens 5 and the measurement point is the focal length of the convergence lens 5, so the measurement point on the surface to be measured is determined. can detect the inclination of

With the above procedure, the detection unit moving mechanism 19, rotation mechanism 20,
is moved by the control unit 21, and the shape of the surface to be covered is measured from the moving distance.

〔Effect of the invention〕

The parabolic antenna surface shape measuring device of the present invention uses a laser beam from a laser instead of adjusting the worker's position while reading the value of an electric micrometer and measuring by reading the value of the electric micrometer as in the conventional device. Emits the
The emitted laser beam is made into parallel light by a collimator lens, and the parallel emitted laser beam is split and converged onto the surface to be measured by a first converging lens and reflected by the surface to be measured. The reflected laser beam that has passed is separated from the emitted laser beam, the separated reflected laser beam is split into two by a beam splitter, and each reflected laser beam is split into two. The third converging lens converges, and the difference in output between the one-dimensional line sensor placed close to the lens and the one-dimensional CCD sensor placed far away from the lens by an equal distance from the rear focal point of the converging lens becomes zero. In order to measure the shape of the parabolic antenna surface by utilizing the fact that the distance between the first converging lens and the surface to be measured is equal to the focal length F of this first converging lens, Even if the angle with the emitted laser beam is not 90 degrees, or the size or shape of the parabolic antenna is different, the shape of the parabolic antenna surface can be accurately measured without contact, and it is possible to use a large number of measurement jigs. This has the effect of eliminating the need for production, storage, and quality control.

[Brief explanation of drawings]

FIG. 1 is a configuration diagram showing one embodiment of the present invention, and FIG.
3 is a diagram showing the reflection state of the parabolic antenna surface, and FIG. 4 is a one-dimensional CCD shown in FIG. 1.
5 is a diagram showing the output current waveform of the sensor 9, FIG. 5 is a diagram showing the output current waveform of the one-dimensional CCD sensor 10 shown in FIG. 1, and FIG. 8 is a diagram showing the output current waveform of the differential amplifier circuit 13 shown in FIG. FIG. 7 is a diagram showing a conventional parabolic antenna measuring device, and FIG. 8 is a diagram showing the state of contact between the probe and the parabolic antenna surface. 1... Parabolic antenna, 2... Laser, 3...
Collimator lens, 4...Half mirror-5, 7, 8゜16...Converging lens, 6...Beam splitter-9
, 10... One-dimensional CCD sensor, 11.12... Output circuit, 13... Differential amplifier circuit, 14... Distance detection section, 15... Mirror, 17... Position detector, 18・
...Angle detection section, 19...Antenna holding section, 20...
・Reference axis, 21...Detection unit moving mechanism, 22.28...
- Rotating mechanism, 23... Control unit, 24... Setting jig, 25... Electric micrometer, 26... Measuring jig, 27... Jig moving mechanism.

Claims (1)

[Claims] A laser as a light source, a collimator lens that makes the laser light emitted from the laser nearly parallel light, a first converging lens that converges the collimated emitted laser light onto the surface to be measured, and two emitted laser lights. a first mirror that separates the reflected laser beam that has passed through the converging lens from the emitted laser beam; and a beam splitter that separates the separated reflected laser beam into two; second and third converging lenses that respectively converge the reflected laser beams; one of the focal points of the converged laser beams is located immediately before, and the other is located immediately after, and two one-dimensional CCDs are arranged perpendicular to the optical axis.
a distance detection section comprising a sensor, two output circuits that output an output proportional to the spot diameter on each one-dimensional CCD sensor, and a differential amplifier circuit that detects a difference in the outputs of the output circuits; A second mirror that obliquely irradiates and reflects the emitted laser light that is split by the first mirror and does not pass through the first converging lens onto the surface to be measured; and a second mirror that irradiates the surface to be measured and reflects it. an angle detection section including a position detector that detects the position of the reflected laser beam; an antenna holding section that holds a parabolic antenna as a measurement object; a reference axis relative to a plane defined by the antenna holding section; a detection unit movement function that holds the distance detection unit and moves it in a direction parallel to the reference axis; and a detection unit movement function that rotates the detection unit movement function about the reference axis on a plane perpendicular to the reference axis. A parabolic antenna surface shape measuring device comprising a rotation function and a control section that controls each of the sections.