JPH0454411A - Optical position measuring instrument - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to an optical position measuring device suitable for use in non-contact measurement of the position, displacement, and thickness of an object.

[Prior Art] FIG. 4 is a block diagram showing the configuration of a conventional optical position measuring device disclosed in, for example, Japanese Patent Publication No. 56-10561 or Japanese Patent Publication No. 59-762.
1 is an object to be measured, 2 is a detection head section, and 3 is a controller section (calculation section). The detection head section 2 includes a light projection lens 4a.
and a light receiving lens (light receiving system) 4b, a light source 5 such as an LED that irradiates a light beam to the object to be measured 1, and a photoelectric converter (PS D).
an optical position detection element 6 called a detector);
The output currents i, t, and xz from both ends of the optical position detection element 6 are amplified to generate a voltage V1 proportional to each current xx, xz.
It is composed of amplifiers 7a and 7b which output as pV2. Further, the controller section 3 includes a light source drive circuit 8 that pulse-drives the light source 5, sample and hold circuits 9a and 9b, a subtracter 10, an adder 11, and a divider 12 for performing arithmetic processing to be described later. There is.

Next, the operation will be explained. The light source 5 is driven by pulses from the drive circuit 8, and repeatedly turns on and off at appropriate time intervals to generate light. The light beam emitted from the light source 5 is focused by the projection lens 4a and projected onto the surface of the object to be measured 1 perpendicularly to the surface. At this time, if the surface of the object to be measured 1 is a general object surface other than an ideal mirror surface, the projected light will be scattered, and from various angles, bright spots of light due to reflected and scattered light,
In other words, a light spot can be observed.

In the detection head section 2, a light receiving lens 4b is installed on the optical axis that forms a predetermined angle θ with the irradiation beam emitted through the light projecting lens 4a, and the image of the aforementioned light spot is
An image is formed on the light receiving surface of the optical position detection element 6 by the light receiving lens 4b. When the optical position detecting element 6 receives light, it performs photoelectric conversion and outputs two currents x1+12 from both ends thereof depending on the imaging position of the light spot. These currents 1x
t12 is amplified by amplifiers 7a and 7b, and each current l
After converting it into a voltage proportional to 12, the sample and hold circuit 9a of the controller section 3.

9b respectively.

The sample and hold circuits 9a and 9b sample the input signal in synchronization with the drive pulse from the light source drive circuit 8,
The pulse waveform light reception signal is converted into a DC signal and output. Then, the subtracter 10 and the adder 11 take out (v, -v2) and (V + vz), respectively, and the divider 12 takes out (v, -v2)/(v□+v2).
) is calculated and output, and a signal d proportional to the center of gravity position of the light intensity of the spot light imaged on the light receiving surface of the optical position detection element 6 is obtained. The position of object 1 is calculated and measured.

[Problems to be Solved by the Invention] In the conventional optical position measuring device, since there is only one light receiving lens 4b, the detection head section 2 is moved while measuring the distance to the object to be measured 1, and the distance to the object to be measured is measured. When measuring the cross section (two-dimensional shape) or unevenness (three-dimensional shape) of object 1,
In areas where the surface has a steep slope, the diffusely reflected light from the surface is blocked by the convex portion of the object 1 itself and does not reach the light receiving lens 4b at all, or only the diffusely reflected light from a part of the light beam spot reaches the light receiving lens 4b. There may be cases where this is not the case. In such a case, measurement may become impossible or a large measurement error may occur.

In order to accurately measure the entire area of the object to be measured 1,
In order to move the position of the light-receiving lens 4b in accordance with the inclination of the surface of the object to be measured 1, it is necessary to rotate the detection head section 2, which requires a complicated movement mechanism and also increases the time required for measurement. There were problems such as length.

This invention was made to solve the above-mentioned problems, and it is an optical positioning method that enables measurement with high precision in a short time while keeping the direction of the detection head fixed even on curved surfaces with steep inclinations. The purpose is to obtain a measuring device.

[Means for Solving the Problems] An optical position measuring device according to the present invention includes a plurality of sets of light receiving systems and optical position detecting elements, and aligns the optical axis of a light beam through a beam spot position formed on an object to be measured. A first switching means is installed on a plurality of different optical axes forming a predetermined angle with the optical position detection element, and switches and inputs the output from each optical position detection element to a calculation section; 1
and a second switching means that branches into a plurality of outputs in synchronization with the switching means.

[Function] In the optical position measuring device according to the present invention, the signals obtained by the plurality of sets of light receiving systems and optical position detection elements provided at mutually different light receiving positions are switched by the first switching means and sent to the arithmetic unit. The calculation result is branched and output as a plurality of outputs corresponding to each optical position detection element by the second switching means. Then, based on the obtained output, the position of the object to be measured is determined by triangulation.

By providing multiple sets of light-receiving systems and optical position detection elements in this way, one of these sets will always output the measurement result at the optimal light-receiving position. No need to rotate.

[Embodiments of the invention] An embodiment of the present invention will be described below with reference to the drawings.

In Fig. 1, 1 is the object to be measured, 2 is the detection head, and 3 is the object to be measured.
is a controller unit (calculation unit), and the detection head unit 2 in this embodiment includes a light projecting lens 4a, two sets of light receiving lenses (light receiving system) 4A and 4B, and a light source that irradiates a light beam to the object to be measured 1. 5 and two sets of optical position detection elements (PSD
) 6, and amplifiers 7a and 7 that amplify the 8-force current lit i2 from both ends of each optical position detection element 6A and 6B and output it as a voltage v1°v2 proportional to each current i, , i2.
b, and the output v1.b from each optical position detection element 6A, 6B as described later. A time division switch (first switching means) 14a which switches and inputs v2 to the controller section 3, respectively.

14b.

Here, as shown in FIG. 1, the two sets of light receiving lenses 4A, 4B and optical position detecting elements 6A, 6B are aligned with the optical axis of the light beam that passes through the beam spot position formed on the object to be measured 1. mutually forming an angle θ1. S4 are respectively installed on different optical axes.

Further, the controller section 3 in this embodiment includes a light source drive circuit 8. Sample hold circuit 9 a e
9 b H subtractor 10. In addition to the adder 11 and the divider 12, there is also a time-division pulse generator 13 that generates time-division pulses.
and the calculation result from the divider 12 is sent to the time division switch 14a,
14b, and a time division switch (second switching means) 15 which branches into two outputs dAydB and outputs the two outputs dAydB.

Each of the time division switches 14a, 14b, and 15 is activated by a pulse signal from the time division pulse generator 13.

Next, the operation of the apparatus of this embodiment will be explained.

Both of the time division switches 14a and 14b receive the pulse signal from the time division pulse generator 13 as a switching command signal, and output the output from the optical position detection element 6A and the output from the optical position detection element 6B.
The output from the controller 3 is alternately switched (time-divided) and output to the controller section 3. Based on the input signal, the controller unit 3 alternately generates signals dA and dB proportional to the light intensity and gravity center position of the spot lights imaged on the light receiving surfaces of the respective optical position detection elements 6A and 6B in exactly the same way as in the conventional case. can be obtained.

The calculation results dA and dB are transmitted to each photodetector element 6A and 6B by a time division switch 15 which also receives a pulse signal from a time division pulse generator 13 as a command signal.
The output is switched from the corresponding output port. In this embodiment, the output of the time division switch 15 is directly output to the output port, but a hold circuit is interposed between the output ports so that a host processor (not shown) can take in the output at any time regardless of the switching timing. You may also do so.

The calculation result dAydB outputted to the output port is input to a host processor or the like, and the position of the object 1 to be measured is calculated and measured by optical triangulation based on each signal dAydB.

Specific application example 1 of the apparatus of this embodiment For example, as shown in FIG. 2.3, a case will be described in which the cross-sectional shape of a cylinder as the object to be measured 1 is measured. As shown in FIG. 2, when measuring the left side of the cylinder, the appropriate reflected light enters the left light receiving lens 4B, so the left optical position detection element 6B
While the upper processor selects and uses the position calculation signal output aa corresponding to , when measuring the right side of the cylinder as shown in FIG. The upper processor selects and uses the position calculation signal output dA corresponding to the left optical position detection element 6A,
Finally, by overlapping these data, it is possible to accurately measure the cross-sectional shape on both the left and right sides.

In this way, according to the device of this embodiment, two sets of light receiving lenses 4A, 4B and optical position detecting element 6A.

Since the signals from 6B are processed in a time-division manner and the corresponding calculation results are output, the optimal light receiving position can be determined from either of the two sets of outputs dApdB according to the slope on the surface of the object to be measured. There is no need to rotate the detection head like in the past.
Not only does this eliminate the need for a rotating mechanism, but it also enables highly accurate measurements in a short period of time.

In addition, since the signals from the two sets of optical position detection elements 6A and 6B are sequentially sent to the controller section 3 for signal processing using the time division switchers 14a and 14b, there is a gap between the detection head section 2 and the controller section 3. connection signal and signal processing circuit are 1
There is also the advantage that it can be done in a systematic manner.

Furthermore, since all of the position measurement values "AydB" from the two sets of optical position detection elements 6A and 6B are output, the upper processor takes the average value of these multiple outputs to eliminate variations in the measurement values due to the influence of the surface to be measured. It is also possible to reduce the amount of water used, and is highly adaptable.

In the above embodiment, a case was explained in which two sets of light receiving lenses and optical position detection elements were provided, but one aspect of the present invention is as follows.
It goes without saying that the invention is not limited to this, and by providing three or more sets, it becomes possible to select and utilize signals from even more optimal light receiving positions.

[Effects of the Invention] As described above, according to the present invention, signals obtained by a plurality of sets of light receiving systems and optical position detection elements provided at mutually different light receiving positions are switched by the first switching means to perform calculations. Since the configuration is such that the calculation results are branched and output as multiple outputs corresponding to each optical position detection element by the second switching means, the direction of the detection head can be adjusted even on a curved surface with a steep slope. This has the effect of allowing high-precision measurements to be made in a short period of time while keeping it fixed.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the configuration of an optical position measuring device according to an embodiment of the present invention, FIGS. 2 and 3 are diagrams for explaining the operation of the device of this embodiment, and FIG. 1 is a block diagram showing the configuration of a position measuring device. In the figure, 1 - the object to be measured, 3 - the controller section (P'
R calculation section), 4A, 4B - light receiving lens (light receiving system), 5 - light source, 6A, 6B - optical position detection element, 14a. 14 b--temporary division switch (first switching means), 15
- a time division switch (second switching means); In addition, in the figures, the same reference numerals indicate the same or corresponding parts. Figure 2

Claims (1)

[Claims] a light source that irradiates a light beam to an object to be measured; a light receiving system that receives scattered light of the light beam from the object to be measured at a predetermined angle; and a light position at which an image of the scattered light is formed by the light receiving system. a detection element; and a calculation unit that calculates the imaging position of the scattered light on the optical position detection element based on the output from the optical position detection element, and In an optical position measuring device that measures the position of an object by triangulation, the light receiving system and the optical position detection element are arranged at a predetermined position with the optical axis of the light beam through a beam spot position formed on the object to be measured. A plurality of sets of optical position detection elements are installed on a plurality of different optical axes forming angles, and the first optical position detection element switches and inputs the output from each optical position detection element to the arithmetic unit.
An optical position measuring device comprising: a switching means; and a second switching means for branching a calculation result from the calculation section into a plurality of outputs in synchronization with the first switching means.