JPH09210639A - Outer diameter measuring device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the reduction of measuring accuracy due to variance and improve the accuracy of measurement of outer diameter by providing an identification mark for identifying the surface of a rotary polygon mirror for scanning parallel scanning light beams and measuring the outer diameter of an object to be measured on the basis of the parallel scanning light beams scanned by the selected surface. SOLUTION: A rotary polygonal mirror 3 for scanning parallel scanning light beams is comprised of an octagonal columnar octahedral mirror 33, and an identification mark 34 to specify one mirror thereamong is attached at the position of a rotor 32 corresponding to the mirror. Then respective mirror surfaces are specified in sequence according to the specified mirror surface where the mark 34 is attached to the mirror 3, and the measured values of the external appearance of an object 6 to be measured that are obtained every mirror surface are compared/examined or all measured values are averaged, then the most optimal mirror surface is specified as a mirror surface at the time of actual measurement. Therefore, the measured value of the outer diameter of the object 6 can be actually obtained on the basis of the output of a light receiving element 7 that is obtained by scanning of the specified mirror surface.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an outer diameter measuring device for measuring the outer diameter of an object to be measured using a parallel scanning light beam.

[0002]

2. Description of the Related Art For example, as shown in FIG. 6, a parallel scanning light beam generating means 21 for emitting a parallel scanning light beam 23b from a window 21a and a parallel scanning light beam generating means 21.
The parallel scanning light beam 23b emitted from the light receiving means 22 faces the light receiving means 22, and the measured object 6 is positioned in the scanning region of the parallel scanning light beam 23b. Alternatively, there is an outer diameter measuring device that measures the outer diameter of the DUT 6 in the scanning direction from the length of time for one scanning time of the bright portion.

Such an outer diameter measuring device irradiates a laser beam 23 from a laser light source 1 toward a fixed mirror 2 as shown in FIG. 5, and rotates the laser beam 23 reflected by the fixed mirror 2. The polygonal mirror 3 is rotated to convert it into a scanning beam 23a, the collimator lens 4 converts it into a parallel scanning light beam 23b, and this parallel scanning light beam 23b converts the collimator lens 4 and the condenser lens 5 of the light receiving unit 22. The object to be measured 6 placed between the two is scanned at high speed.

The light receiving means 22 is designed so that the parallel scanning light beam 23b emitted from the parallel scanning light beam generating means 21 is received by the light receiving element 7 located at the focal position of the condenser lens 5. 23b is the DUT 6
The output voltage a is output at a high level (or low level) when not blocked by, and at a low level (or high level) when the parallel scanning light beam 23b is blocked by the DUT 6. That is, the time when the output is at the low level (or the high level) in one scanning time for scanning one mirror surface of the rotary polygon mirror 3 is the time when the DUT 6 is present.

The output voltage of the light receiving element 7 is sent to the amplification / binarization circuit 8 and shaped into a binarized pulse b by the amplification / binarization circuit 8, which corresponds to a certain time t of the DUT 6. It is sent to the detection circuit 9 for detecting the portion. The output of the detection circuit 9, that is, the pulse c corresponding to a certain time t of the DUT 6 is sent to the AND circuit 10, and the AND circuit 10 receives the clock pulse cp from the clock pulse oscillator 11.
It outputs the clock pulse p at the time t when the pulse c is input. The output pulse p of the AND circuit 10 is the counter 1
Counted as 2.

The arithmetic processing circuit 13 is a detector 1 including a photodiode for detecting the parallel scanning light beam 23b at the edge of the window 21a of the parallel scanning light beam generating means 21.
The signal from 5, that is, the scanning synchronization signal is input, the count value of the counter 12 is fetched for each scanning synchronization signal,
The outer diameter of the DUT 6 is calculated, and the result is displayed appropriately.

[0007]

By the way, in the outer diameter measuring device constructed as described above, when the object 6 to be measured has a taper as shown in FIG. 6, for example, the mirror surface of the rotary polygon mirror 3 is used. If there is variation in the mirror surface angle, the scanning position of the parallel scanning light beam shifts from 23b to 23c due to the mirror surface, the measurement position of the DUT 6 shifts, and an error occurs in the measurement value. Further, if there is a variation in the reflectance between the mirror surfaces of the rotary polygon mirror 3, the time during which the threshold value V1 when binarizing is exceeded as shown in FIG. The accuracy of the measured outer diameter is reduced.

Further, in such an outer diameter measuring device, the dimension up to the DUT 6 may be measured with the edge of the window 21a of the parallel scanning light beam generating means 21 as a reference.
Particularly in such a case, if the rotary polygon mirror 3 is eccentric, as shown in FIG. 7, the edge of the window 21a and the DUT 6 are measured.
The detection time between the edges of each mirror surface is t1, t2 or t
3 and t4, and as shown in FIG.
When the shape of the window 21a is deformed and the scanning position of the parallel scanning light beam shifts from 23b to 23c, the detection time between the edge of the window 21a and the edge of the measured object is t7 at each mirror surface,
There is a variation with t8.

In order to eliminate such variations,
It is required that the configurations of the rotating polygon mirror, windows, etc. that make up the outer diameter measuring device be formed extremely accurately and be assembled extremely accurately, and that the arithmetic processing circuit that calculates the outer diameter of the object to be measured also be configured. A large number of correction amounts need to be calculated, which is complicated and makes the outer diameter measuring device costly.

The present invention has been made in view of the above circumstances, and provides an outer diameter measuring device which has a simple structure and which can prevent the measurement accuracy from deteriorating due to the above variations and further improve the measurement accuracy. It is intended to be provided.

[0011]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a parallel scanning light beam generating means for emitting a parallel scanning light beam which is scanned by the rotation of a rotary polygon mirror, and a parallel scanning light beam emitting means for emitting a parallel scanning light beam. A light receiving means for receiving the scanning light beam, and arranging an object to be measured in a scanning region of the parallel scanning light beam between the parallel scanning light beam generating means and the light receiving means, In the outer diameter measuring device for measuring the outer diameter of the object to be measured from the interruption time of the scanning light beam, an identification means for identifying the surface of the rotary polygon mirror that scans the parallel scanning light beam is provided, and is selected by the identification means. It is achieved by providing an outer diameter measuring device characterized in that it is possible to measure the outer diameter of the object to be measured from a parallel scanning light beam scanned by a curved surface.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION An outer diameter measuring apparatus according to the present invention is similar to the outer diameter measuring apparatus described with reference to FIG. 5, and includes a laser light source, a rotary polygon mirror, a collimator lens, and a detection for forming a scanning synchronization signal. Scanning light beam generating means including a measuring device, a condenser lens, a light receiving means including a light receiving element, an amplification / binarization circuit, a detection circuit for detecting a portion of the measured object corresponding to a certain time, an AND circuit, and a clock Pulse oscillator,
An outer diameter measuring device having a counter and the like is provided with identification means for identifying the surface of the rotary polygon mirror and an arithmetic processing circuit.

The identification means for identifying the surface of the rotary polygon mirror is, for example, provided with a recognition mark for identifying the mirror surface on the rotary polygon mirror,
It is composed of a mark detector such as a photo interrupter for reading the recognition mark, and the arithmetic processing circuit inputs the mark signal and the scan synchronization signal of the mark detector, and the output signal and the scan synchronization signal of the mark detector. Detects the mirror surface that is scanning, selects the count value of the counter when it is scanned by a pre-specified mirror surface, and calculates the count value with a predetermined correction amount Is configured so that

The outer diameter measuring device constructed as described above is
Each mirror surface is specified based on the mirror surface specified by the recognition mark attached to the rotating polygon mirror, and the measured values of the outer diameter of the DUT obtained for each mirror surface are compared and examined, or all measured values are averaged. The most appropriate mirror surface can be specified as the mirror surface at the time of actual measurement, and at the time of actual measurement, the measured value of the outer diameter of the object to be measured can be obtained from the output of the light receiving element that is scanned by the specified mirror surface I am able to do it. Therefore,
It is possible to always obtain measured values under the same conditions,
There is no variation in the measured values, and the accuracy is improved.

[0015]

Embodiments of the present invention will be described below with reference to FIGS. 1 is a block diagram of an outer diameter measuring apparatus according to an embodiment of the present invention, FIG. 2 is a timing diagram of the outer diameter measuring apparatus shown in FIG. 1, and FIG. 3 is an example applied to the outer diameter measuring apparatus shown in FIG. It is a top view of a polygon mirror. FIG. 4 is a side view of the polygon mirror shown in FIG. It should be noted that common portions are denoted by the same reference numerals throughout the drawings, and detailed description of overlapping portions will be omitted.

In FIG. 1, reference numeral 21 is a parallel scanning light beam generating means, which is a laser light source 1, a rotary polygon mirror 3, a collimator lens 4, a detector 15 for forming a scanning synchronization signal, and a window 21.
a and the like, and is arranged and configured in the same manner as the parallel scanning light beam generating means of the outer diameter measuring device described with reference to FIG. Reference numeral 22 denotes a light receiving means, which includes a condenser lens 5 and a light receiving element 7, and is arranged in the same manner as the light receiving means of the outer diameter measuring apparatus described with reference to FIG.

The configuration of the amplification / binarization circuit 8, the detection circuit 9 for detecting a portion of the object to be measured corresponding to a certain time, the AND circuit 10, the clock pulse oscillator 11, and the counter 12 is also shown in FIG. The outer diameter measuring device described above is configured in the same manner. Reference numeral 14 is a detector that detects one specific mirror surface of the rotary polygon mirror 3, and 16 is an arithmetic processing circuit.

In this embodiment, the rotating polygon mirror 3 is constructed as shown in FIGS. 3 and 4. That is, the rotary polygon mirror 3 includes a flat motor 31 fixed to a substrate 30 on which a motor drive circuit and the like are mounted, a rotor 32 of the flat motor 31, and an octagonal prism 8-shaped mirror 33 fixed to the rotor 32. The identification mark 34 for identifying the one mirror surface is attached to the position of the rotor 32 corresponding to the one mirror surface of the eight-sided mirror 33.

Further, in this embodiment, the detector 14 for detecting one specific mirror surface of the rotary polygon mirror 3 is arranged near the rotor 32 as shown in FIG. 3, and the recognition mark 34 attached to the rotor 32 is provided. Photointerrupter 3 for optically detecting light
5.

The arithmetic processing circuit 16 is, as shown in FIG.
The output signal of the detector 14 that detects a specific mirror surface, that is, the mark signal 14a output by the photo interrupter 35 that has detected the recognition mark 34, and the scan synchronization of the detector 15 that forms the scan synchronization signal following this mark signal 14a. The signals 151 to 158 are sequentially input in accordance with the rotation of the rotary polygon mirror 3, and the mirror surfaces of the rotary polygon mirror 3 which are scanning the laser beam 23 are sequentially arranged, for example, in the order of first, second, third ... Identify.

Then, the amplification / binarization circuit 8 (the output signals b1 to b1 of the amplification / binarization circuit 8 are performed for each scanning by the specified first to eighth mirror surfaces.
b8), a detection circuit 9 (the output signals c1 to c8) for detecting a portion of the DUT corresponding to a certain time, and an AND circuit 1
The count value of the counter 12 that sequentially counts each of the pulses p1 to p8 formed via 0 is input, and is collected in association with the first to eighth mirror surfaces.

The arithmetic processing circuit 16 has a rotary polygon mirror 3 in advance.
One of the 1st to 8th mirror surfaces and the correction amount obtained by the variation between each surface that corrects the count value corresponding to that mirror surface, etc. are set, and at the time of actual measurement, it corresponds to the set mirror surface Select the count value to be calculated, calculate the correction amount, and obtain the measured value.

In the above embodiment, the identification mark 34 and the photo interrupter 33 attached to one position of the rotor 32 are used as the identification means for identifying the surface of the rotary polygon mirror, but the surface of the rotary polygon mirror is identified. For example, the identifying means may be configured such that one of the corners between the surfaces of the rotary polygon mirror is deformed by providing a curvature, and this deformation is detected, or a magnet is attached to the rotor of the motor to which the polygon mirror is fixed, It may be detected by a hall element, or an identifier for identifying each surface may be attached and the identifier may be read.

Further, the rotary polygon mirror is not limited to eight faces, and may be a plurality of faces, and the motor is not limited to the flat motor, and needless to say, may be a motor having another shape or structure. Further, the scanning synchronization signal may be detected on the rotary polygon mirror side.

[0025]

As described above in detail, according to the present invention, the rotary polygon mirror is identified and the surface on which the measurement is currently performed is known. As a result, it is possible to perform actual measurement on a specific one surface of the polygonal mirror having a plurality of surfaces, and it is possible to improve the measurement resolution. Also, by adding identification,
It is possible to improve the measurement accuracy by correcting the inclination of the mirror surface on each surface, and in addition, average the measured values of each surface of the rotating polygon mirror multiple times. Even in the required measurement, the accuracy can be improved with a small number of rotations.

[Brief description of drawings]

FIG. 1 is a configuration diagram of an outer diameter measuring device according to an embodiment of the present invention.

FIG. 2 is a timing diagram of the outer diameter measuring device shown in FIG.

FIG. 3 is a plan view of an example polygonal mirror applied to the outer diameter measuring device shown in FIG.

FIG. 4 is a side view of the polygon mirror shown in FIG.

FIG. 5 is a configuration diagram of a conventional outer diameter measuring device.

FIG. 6 is a perspective view for explaining the deviation of the scanning position of the outer diameter measuring device.

FIG. 7 is a waveform diagram for explaining variations in measured values due to decentering of the rotary polygon mirror.

FIG. 8 is a waveform diagram for explaining variations in measured values due to differences in reflectance of the rotary polygon mirror.

FIG. 9 is a waveform diagram for explaining variations in measured values due to deformation of a window shape.

[Explanation of symbols]

 1 Laser Light Source 2 Fixed Mirror 3 Rotating Polygonal Mirror 4 Collimator Lens 5 Condenser Lens 6 DUT 7 Photosensitive Element 8 Amplification / Binarization Circuit 9 Detection Circuit 10 AND Circuit 11 Clock Oscillator 12 Counter 14 Detector 15 Scanning Sync Signal Forming detector 16 Arithmetic processing circuit 23 Laser beam 31 Motor 32 Rotor 33 Polygonal mirror 34 Recognition mark 35 Photo interrupter

Claims (1)

[Claims] 1. A parallel scanning light beam generating means for emitting a parallel scanning light beam which is scanned by rotation of a rotary polygon mirror,
A light receiving means for receiving the parallel scanning light beam beam emitted from the parallel scanning light beam generation means, and a light receiving means for receiving the parallel scanning light beam beam between the parallel scanning light beam generation means and the light receiving means. In an outer diameter measuring device that arranges a measurement object and measures the outer diameter of the measurement object from the blocking time of the parallel scanning light beam by the measurement object, identifies the surface of the rotating polygon mirror that scans the parallel scanning light beam. An outer diameter measuring device, characterized in that it is possible to measure the outer diameter of the object to be measured from a parallel scanning light beam scanned by the surface selected by the identifying means.