JPH032606A - Outer-size measuring apparatus - Google Patents

Abstract

PURPOSE:To simplify signal processing and to improve measuring accuracy and response by providing a converging system where in a reflected beam from a material to be measured is received with a one-dimensional optical- position detecting element, and the image forming position has an elliptical pattern. CONSTITUTION:A light beam 4 from a light projecting system 8 is projected and swept on a material to be measured. A reflected beam 11 is received with a one-dimensional optical-position detecting element 14. Output currents I1 and I2 are amplified. The height size is operated in an operating circuit 23. At this time, the image is formed through a condenser lens 15 and a cylindrical lens 16 in a converging system 17 so that the position of the image formation has an elliptical pattern whose long side is perpendicular to the direction of displacement. In this way, the change of the converging system 17 is detected as the amount of the displacement of the one-dimensional detecting element 14. Since the amount of displacement is proportional to the length of the side surface of the material, i.e. the height, the height size can be obtained from the amount of displacement. Thus the one-dimensional detecting element 14 can be applied.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a measuring device that projects a light beam such as a laser beam onto an object to be measured and detects the external dimensions of the object from the reflected light beam. It is something.

[Conventional technology]

FIG. 5 is a perspective view showing a conventional external dimension measuring device of this kind. In the figure, (1) is an object to be measured placed on a table (2), and here the height dimension H is the external dimension to be measured. (3) is a light source that emits a laser beam (/1), ((5) is a rotating mirror, (6) is a fixed mirror, (
7) is a focusing lens. A projection system (8) is configured by (31+51 to ■), and a laser beam (4 ) is illuminated and swept. (9) is the object to be measured (1) of the laser beam 4) that is illuminated and swept.
The trajectory on the surface and table (21) is shown.

0 is a two-dimensional optical position detection element that receives a reflected laser beam (11) in which the laser beam (A) is reflected and diffused by the surface of the object to be measured (1) or the surface of the table (21). That is, from the direction perpendicular to the table (21
The reflected laser beam (11
) is imaged on the detection surface and its position is output as a signal. (12) is a CRT that receives the output of the two-dimensional optical position detection element and displays its imaging position; (+3) is this CRT;
The locus of the imaging position displayed on RT (12) is shown.

In this way, the reflected laser beam (11) of the laser beam 4) is projected and swept over the area including the object to be measured (1).
2-dimensional optical position detection element (receives 101 TE light, CI'r (
The height dimension l] is determined from the imaging locus (13) on +21.

This height 1; Nori and Tl! , 1lill constant (1) has a proportional relationship with the height H (+P), so in the end CRT (1
This means that the external dimensions of the object to be measured (1) can be obtained without contact from the output screen on the 2j. Measured if necessary! T! The width direction dimension of II (1) can also be measured in the same manner.

Here, the reason why an optical position detection element capable of two-dimensional position detection is required is as follows. That is, CR
As can be seen from the output trajectory (13) on T(121), in order to specify the height of the vertical portion, the horizontal portions at both ends, the projection sweep trajectory (9) of the laser beam (4)
Expressed as , the upper surface of the object to be measured (1) and the table (
This is because it is necessary to detect the reflected laser beam from the surface portion (2) and the image formed by (11), and ultimately it is necessary to display the trajectory (9) in a two-dimensional form.

[Problem to be solved by the invention]

As described above, the conventional external dimension 1111 determination device requires image processing using the two-dimensional optical position detection element 00). As a result, signal processing becomes complicated, and furthermore, there are problems in that high-speed processing is difficult and resolution is low.

This invention was made in order to solve the above problems, and enables the application of a one-dimensional optical position detection element, thereby realizing simple signal processing, high-speed processing, and high resolution. The purpose is to provide complete equipment.

[Means to solve the problem]

The external dimension measuring device according to the present invention includes a light projection system that projects and sweeps a light beam over a region including an object to be measured, and a light beam reflected and diffused by the object to be measured at a predetermined angle with the direction of the light projection. a one-dimensional optical position detection element that receives light from a direction and detects an imaging position displaced by the sweep; and a one-dimensional optical position detection element arranged on the optical path of the reflected light beam so that the image formed on the one-dimensional optical position detection element is in the displacement direction. The second embodiment is equipped with a focusing system that focuses the reflected light beam into an elliptical shape whose long sides are perpendicular to the direction.

[For production]

When the light beam from the light projection system moves by sweeping over, for example, the side surface of the object to be measured, the angle of incidence of the reflected light beam on the one-dimensional optical position detection element changes with this movement.

In this case, the image formation on the one-dimensional optical position detection element is as follows:
Since the focusing system forms an ellipse whose long sides are perpendicular to the direction of this change, the change is detected as the amount of displacement of the imaging position on the one-dimensional optical position detection element. Since the detected displacement amount is proportional to the length of the side surface of the object to be measured, that is, the height dimension, the height dimension of the object to be measured can be determined from the above displacement amount.

Furthermore, by detecting the time interval at which the imaging position shifts, we can use this time interval and the sweep speed to determine the external dimensions of the object in the sweep direction. Dimensions can be determined.

〔Example〕

FIG. 1 is a diagram showing the overall configuration of an external dimension measuring device according to an embodiment of the present invention. In the figure, (11F21
(41 (81 (91 (l l 1, A, and B are the same as the conventional one. However, these are views of the conventional perspective view of Fig. 5, looking from the front left to the rear right. (14) is a one-dimensional optical position detection element (hereinafter simply referred to as detection element), whose one-dimensional detection direction is the direction in which the reflected laser beam (11) is displaced, which is shown as the X axis in the figure. Note that the direction perpendicular to the X-axis and shown as the Y-axis in the figure is the sweeping direction of the laser beam (4).

(15) is a condensing lens, and (16) is a cylindrical lens whose focal length differs depending on the X-axis direction and Y-axis direction of the lens surface.
! 7). Then, in the X-axis direction, it acts as a convex lens with the same focal length on the detection element (14), and in the Y-axis direction, it acts as a convex lens with an even longer focal length, and the image is formed with the long side in the Yllll11 direction. It becomes an elliptical shape.

Figures 2 and 3 explain how this image is formed.
2 is a view of the focusing system (17) of FIG. 1 seen from the right side thereof, and FIG. 3 is a view of the detection element (14) of FIG. 2 seen from below. In both figures, A zero B8 is the table (2
) Detection elements (I4) corresponding to points A and B set on
The image formed above, C*, is an image formed on the detection element (14) corresponding to the point C set at the center of the upper surface of the object to be measured (the moon).

Returning to Figure 1, (+8) (+9+ is the detection element (14)
Current output from 1. , an amplifier circuit that converts L into voltage and further amplifies it, (20) is an amplifier circuit (+8) (19
), (21) is an addition circuit that calculates the sum of outputs from amplifier circuits (18) and (19), and (22) is an addition circuit (22) that calculates the difference between the outputs from subtraction circuit (20). 2
(1) is a division circuit that divides by the output of (23) is a subtraction circuit that divides by the output of (2).
0) in the X-axis direction, that is, the reflected laser beam (II
), and therefore the height dimension H of the object to be measured (1), (24) applies a reset pulse Pl when the output J rises due to the sweep, and when the output J falls. A pulse shaping circuit that outputs each latch pulse P2, (25) is a reference clock signal source (26)
Both pulses P, , P based on the clock pulse P, from
This is a counter that calculates the width dimension W of the object to be measured (1) as the diameter in the Y-axis direction by counting clock pulses P within a time interval of 1-2.

Next, the operation will be explained. The light projection system (8) is driven to direct the laser beam (A) onto the table (1) containing the object to be measured (1).
Sweep between points A and B on 21. The reflected laser beam (11) is then imaged onto a detection element (14) by a focusing system (17). Here, this imaging is the second
As shown in Figures 3 and 3, it has an elliptical shape with the long side in the Y-axis direction. ) can also be used to detect the imaging position within the gold range of the sweep.

Output 1 of the one-dimensional optical position detection element (14). , a subtraction circuit (20), an addition circuit (21) and a division circuit (
Since the principle of calculating the imaging position of the received light using 22) is well known, the explanation thereof will be omitted.

The arithmetic circuit (23) receives the third signal from the output J of the division circuit (22).
The distance between image formation A* or B8 and image formation C8 shown in the figure is calculated. Since this interval is proportional to the height H of the object to be measured (1), the height H can be determined from the output of the arithmetic circuit (23).

Next, the procedure for determining the width W of the object to be measured (1) will be explained with reference to FIG. The time width in the figure corresponds to the sweep speed of the reflected laser beam (11). In the same figure,
The "L°° level of the output J of the division port 1i'8 (22>" corresponds to the image forming position of AI=, B* in Fig. 3, and the "H°" level corresponds to the image forming position of C8. .Pulse forming concave 1
i'! (The 24+ outputs a reset pulse P1 at the rising edge of the output J. In response, the counter (25) starts counting the clock pulse P3 from the reference clock signal source (26). Next, the output J falls. The latch pulse P2 is output, and the counter (25) finishes counting the clock pulse P.

The counter (25) determines the pulse width Tw of the output J from the obtained count number n, and calculates the width dimension W of the object to be measured (1) from the product Tw-V of this pulse width Tw and the sweep speed ■. .

When a one-dimensional optical position detection element (14) is used, for example, a one-dimensional optical position detection element (14) with a detection part m 1 n + m x 3 mm can achieve high performance with a single position detection resolution of 1/10000 and a frequency response of several hundred KHz, and can be used to detect secondary elements. Compared to when using
Measurement accuracy and responsiveness as a Jt'1 constant device are greatly improved.

In the above embodiment, a case has been described in which both the height dimension H and the width dimension W of the object to be measured (11) are measured, but a configuration may be adopted in which only one of them is measured.

In addition, in the above embodiment, a one-dimensional optical position detection element was used as a light receiving element, but a one-dimensional photodiode array or a one-dimensional optical position detection element was used as a light receiving element.
A light receiving element such as a dimensional image sensor can also be applied as an equivalent device, and the same effect can be obtained.

Furthermore, a cylindrical lens (16) is installed in the focusing system (17).
However, for example, a diffraction grating or the like may be used to obtain an elliptical image.

〔Effect of the invention〕

Since the present invention is constructed as described above, it is possible to apply a one-dimensional optical position detection element, and the measurement accuracy and responsiveness of the measuring device are improved based on its high resolution and high-speed response characteristics.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the entire external dimension measuring device according to an embodiment of the present invention, FIG. 2 is a diagram explaining the function of its focusing system, and FIG. 3 is a one-dimensional optical position detection element shown in FIG. 2. FIG. 4 is a waveform diagram illustrating the operation of the device shown in FIG. 1, and FIG. 5 is a perspective view showing the overall configuration of a conventional external dimension measuring device. In the figure, (1) is the object to be measured, (4) is the laser beam as a light beam, (8) is the projection system, (11) is the reflected laser beam as the reflected light beam, and (14) is the one-dimensional light beam. Position detection element, (17> is focusing system, A*, B*, C
m is the image formation. Note that the same reference numerals in each figure indicate the same or corresponding parts. Figure 2 Agent: Masuo Oiwa, patent attorney

Claims (1)

[Claims] A light projection system that projects and sweeps a light beam over an area including the object to be measured, receives the light beam reflected and diffused by the object to be measured from a direction having a predetermined angle with the direction of the light projection, and is displaced by the sweep. a one-dimensional optical position detection element for detecting an image formation position, and a one-dimensional optical position detection element disposed on the optical path of the reflected light beam,
An external dimension measuring device comprising a focusing system that focuses the reflected light beam so that the image formed on the one-dimensional optical position detection element has an elliptical shape with a long side in a direction perpendicular to the displacement direction.