JPH04204106A - Optical displacement gage camera - Google Patents

Abstract

PURPOSE:To enable highly-precise measurement of displacement of a material of which a change in the shape is small, by a construction wherein an optical imaging system which images a light flux from a reference on an object of measurement on a prescribed focal plane and a semiconductor position detector are held in a case being immovable in relation to the object of measurement. CONSTITUTION:A camera 10 is constructed of light sources 11 applying light to bench marks MK, optical imaging systems 12 imaging reflected light fluxes from the marks MK on prescribed focal planes, semiconductor position detectors 13 sensing the reflected light fluxes and outputting voltage signals corresponding to light-sensing positions, and cases 14 accommodating the optical systems 12 and the detectors 13 and being immovable in relation to a test piece TP. A beam light from the light source 11 is applied onto the test piece TP and the mark MK is imaged on the detector 13. Next, in the detector 13, the amount of movement of the mark MK is computed from a terminal voltage obtained sequentially and from a voltage value before a test. The amount of displacement of the test piece TP can be computed from the amount of movement of this mark MK.

Description

DETAILED DESCRIPTION OF THE INVENTION A. Field of Industrial Application The present invention relates to an optical displacement meter camera for measuring the amount of elongation of a test piece.

B. Conventional technology FIG. 3 shows an illumination light source 21 and a CC which is a photoelectric conversion element.
A conventional optical displacement meter camera 20 is shown, which includes a D22 and an imaging optical system 23, and detects a gauge mark MK on a test piece TP by a CCD 22. Here, the imaging position of the gauge mark on the CCD 22 is shown. The signal is input to a control circuit 31', and the control circuit 31 controls tracking of the optical camera 20 using a pulse motor 33. That is, the optical camera 20 is driven and controlled by the pulse motor 33 via the motor drive circuit 32 so that the image formation position is always the same on the CCD 22. The control circuit 31 also calculates the amount of elongation based on the number of pulses of the pulse motor 33 and displays it on the display section 35 via the display drive circuit 34. The camera 20 follows the elongation in this way when testing a material such as rubber, in which the amount of displacement of the test piece TP is larger than the measurement range of the CCD 20. When the elastic modulus is high and the amount of displacement is small, such as a metal material, that is, when the amount of displacement is smaller than the measurement range of the CCD 20, it is not necessary to make the camera 2° follow the displacement.

Problems to be solved by the C0 invention However, since the resolution of the COD is low in conventional optical displacement meter cameras that use COD, the displacement measurement accuracy for materials with high elastic modulus and small displacement such as metal materials is low. The problem is that it is difficult to measure and is virtually impossible to measure.

Further, in the conventional displacement meter camera, one camera is required for each pair of gauge line marks, and it is not possible to sufficiently reduce the size and cost of the camera.

An object of the present invention is to provide an optical displacement meter camera that can accurately measure the displacement of a material with a high elastic modulus and a small amount of deformation, and that can be easily miniaturized.

The present invention will be explained in conjunction with FIG. 1 showing an embodiment of the invention. an imaging optical system 12 for imaging; a semiconductor device detector 13 disposed on a predetermined focal plane for receiving the light beam and outputting a voltage signal according to the receiving position; the imaging optical system 12 and the semiconductor device detector The above object is achieved by providing a case 14 that accommodates the casing 13 and is immovable relative to the measurement target during testing.

Further, the present invention will be explained in conjunction with FIG. 2 which is an embodiment. a pair of imaging optical systems 112U and 112L, and a single photoelectric conversion element 11 that is arranged on a predetermined focal plane and receives each of the light beams and outputs a signal according to the light receiving position.
3 and a case 114 that accommodates the imaging optical systems 112U and 112L and the photoelectric conversion element 113, the above object is achieved.

E0 Effect - Claim 1 - The reflected light beam from a reference point such as the gauge line mark MK of the test piece TP is imaged on the semiconductor device detector 13 by the imaging optical system 12. Since the semiconductor device detector 13 outputs a voltage corresponding to the light receiving position to the output terminal, the amount of movement of the reference point can be detected based on these output voltages. becomes computable. Furthermore, since the semiconductor device detector has a higher resolution than a CCD, it is possible to measure minute displacements with high precision.

Claim 2 - Each of the light beams from the pair of reference points forms an image on a single photoelectric conversion element 11, and the image forming position changes according to the deformation of the test piece TP. The amount of displacement of the test piece TP is detected from the output signal of the photoelectric conversion element 113 accompanying such a change in the imaging position.

In the above-mentioned sections and section E, which describe the present invention in detail, figures of embodiments are used to make the present invention easier to understand, but the present invention is not limited to the embodiments.

F. Embodiment An embodiment of the present invention will be described based on FIG. 1 showing the configuration of an optical displacement meter camera according to the present invention.

10A and IOB (under U, cell represented by 10) are a pair of optical displacement meter cameras, which are installed so as to face a pair of gauge line marks MK provided on the test piece TP, respectively. The camera 10 includes a light source 11 (a halogen lamp, a semiconductor laser, etc.) that irradiates light onto the gauge mark MK.
an imaging optical system 12 that forms an image of the reflected light beam from the high-intensity gauge mark MK on a predetermined focal plane; a semiconductor device detector (PSD) 13 outputting to both terminals;
housing an imaging optical system 12 and a semiconductor device detector 13;
It consists of a case 14 that does not move with respect to the test piece TP during testing. Note that the positions of the pair of cameras IOA and 10B can be adjusted according to the distance between the gauge lines of the test piece TP.

Displacement detection by the pair of optical displacement meter cameras 10 configured as described above is performed as follows.

Light from the light source 11 is irradiated onto the test piece TP as a beam of light. The optical axis of the imaging optical system 12 is aligned with each of the gauge marks MK, and the high-intensity gauge marks MK are imaged by the imaging optical system 12 onto the semiconductor device detector 13 . As is well known, a voltage signal corresponding to the light receiving position is extracted from both end terminals of the semiconductor device detector 13, and the light receiving position changes according to the elongation of the test piece TP. Therefore, the voltage values of both terminals before the test are memorized, and the amount of movement of the gauge line mark MK is calculated from the terminal voltages obtained sequentially when the test piece TP is stretched with the start of the test and the voltage values before the test. do. Because the upper and lower St line marks MK move by different amounts in the same direction due to the deformation of the test piece TP, the pair of cameras IOA
, the amount of displacement of the test piece TP can be calculated based on the amount of movement of each gauge line determined based on the terminal voltage of each of the semiconductor device detectors 13 provided in the IOB.

Since the elastic modulus of the test piece TP is high and the amount of deformation is small, the reflected light flux from the marked line moves within the measurement range of the semiconductor device detector 13, and therefore it is necessary to follow the camera 1° according to the amount of displacement. Therefore, the displacement meter camera can be simplified. Furthermore, since the resolution of the semiconductor device detector 13 is higher than that of a charge-coupled photoelectric conversion device (CCD), minute displacements can be measured with high precision.

FIG. 2 shows a second embodiment, in which a single camera
0, the displacement of a pair of marked lines is detected.

That is, within a single case 114, a pair of light sources 11 are provided.
1U, IIIL, and a pair of imaging optical systems 112U, 112
L, a single semiconductor device detector 113, a total reflection mirror 115 that guides the reflected light flux from the upper gauge line mark MKU to the semiconductor device detector 113, and a total reflection mirror 115 that guides the reflected light flux from the lower gauge mark MKL to the semiconductor device detector 113. A half mirror 116 leading to a device detector 113 is provided. The reflected light beam from the total reflection mirror 115 passes through the half mirror 116 and is incident on the semiconductor device detector 113, but when there is no load, each reflected light beam from the upper and lower gauge marks MKU and MKL is detected by the semiconductor device detector. The optical system is set so that the light is incident on the same point on the vessel 113. It may be made to enter at different points.

Prior to testing, the voltage across both terminals of the semiconductor device detector 113 is read and stored. When a tensile load is applied to the test piece TP, the test piece TP stretches and each gauge line mark MKU, MK
L moves, and the light receiving position on the semiconductor device detector 113 changes. Since the amount of elongation of the upper and lower marked lines is different, the two light receiving positions on the semiconductor device detector 113 are separated according to the amount of elongation.

By measuring the fluctuation in the voltage between the pair of terminals of the semiconductor device detector 113 at that time, the amount of elongation of the test piece TP can be detected.

Note that the amount of elongation can be determined from the fluctuation of the voltage between the pair of terminals in the following manner. First, a tensile load is applied to a reference test piece, and the elongation of the test piece is accurately detected using a separately installed extensometer. Then, this detected value is associated with the voltage across both terminals of the semiconductor device detector 113, thereby creating reference back data. The amount of elongation of the test piece can be determined by comparing this pack data with the fluctuation of the voltage across the pair of terminals during the test.

In this embodiment, only one semiconductor device detector 113 is required, and a compact camera can be provided. Note that in this second implementation @b, if the resolution of charge-coupled photoelectric conversion elements improves in the future, a charge-coupled photoelectric conversion element will be used instead of a semiconductor device detector, and the amount of minute elongation will be increased. Can be detected accurately. If high accuracy is not desired, currently available charge-coupled photoelectric conversion elements may be used.

Furthermore, in the above description, the illumination light source is integrally provided on the camera side, but it may also be provided separately from the camera case.
A light source may be provided at the marked line position of the test piece, and the position of this light source may be detected by a photoelectric conversion element. Furthermore, a similar light source may be provided in a jig of a material testing machine, such as a platen of a compression testing machine.

As described in detail of the G6 invention, according to the invention of claim 1, the amount of displacement of a test piece having a high elastic modulus and a minute amount of displacement can be measured with high accuracy.

Further, according to the second aspect of the invention, since the pair of light beams are guided onto a single photoelectric conversion element, it is possible to provide a compact and inexpensive displacement meter camera.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram showing the configuration of a first embodiment of the optical displacement meter camera according to the present invention, FIG. 2 is a configuration diagram showing the configuration of the second embodiment of the optical displacement meter camera according to the present invention, FIG. 3 is a diagram showing a conventional example. 10, IOA, IOB, 110: Optical displacement meter camera 1
1, IIITJ, IIIL: Light source 12.112U, 112L: Imaging optical system 13.113:
Semiconductor device detector 14.114: Case 115: Total reflection mirror 116: Half mirror TP: Test piece MK, MKU, MKL: Marking line mark Patent applicant Shimadzu Corporation Representative Patent attorney Fuyuki Nagai Figure 1 2 figure 14L

Claims (1)

[Scope of Claims] 1) An imaging optical system that forms an image of a light beam from a reference point on a measurement object onto a predetermined focal plane; an optical displacement device comprising: a semiconductor position detector that outputs a corresponding voltage signal; and a case that houses the imaging optical system and the semiconductor device detector and is immovable with respect to the measurement target during testing. meter camera. 2) a pair of imaging optical systems that respectively form images of light beams from a pair of reference points on the measurement object onto a predetermined focal plane; and a pair of imaging optical systems that are arranged on the predetermined focal plane and receive each of the light beams and move the light beams to the light receiving positions. a single photoelectric conversion element that outputs a corresponding signal,
An optical displacement meter camera comprising the imaging optical system and a case that houses the photoelectric conversion element.