JPS6112203B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a device for measuring the distance to a measurement target over a wide range and in a non-contact manner.

In general, measuring the distance to a measurement target or changes in a measurement target is the most basic measurement technology, and conventional methods include differential transformers, eddy current coil methods, laser modulation phase detection methods, and optical triangulation methods. is put into practical use.

In particular, the optical triangulation method is an excellent measurement method that allows non-contact measurement, can measure relatively long distances, and has high measurement accuracy.

However, even this method has drawbacks such as slow measurement speed and increased errors due to out of focus when the measurement range is widened before it can be put to practical use as an automatic measuring device.

In view of these circumstances, the present invention has been developed to measure the distance to a measurement target over a wide range, and to do so without contact.
We provide an excellent automatic measuring device with the ability to measure at high speed and with high precision.The main points of this device are a light source that emits a spot light, and a spot light from the light source that is incident on the surface of the object to be measured. An optical system on the incident light side consisting of a lens that forms a minute spot light into an image, a fixed and movable prism or lens that maintains a constant optical distance between the lens and the surface to be measured, and a light beam from the optical system. a condensing optical system consisting of a mirror that maintains a constant angle with respect to the axis and condenses the reflected light of the minute spot light on the surface of the object to be measured, and an optical system consisting of a fixed and movable prism or lens; a deviation measuring device that optically measures the deviation from the intersection of the optical axis of the condensing optical system and the optical axis on the incident light side to a minute spot light on the surface of the object to be measured; a servo device for moving a moving part of a measuring device on which an optical system and a condensing optical system are mounted; a displacement measuring device for measuring a moving distance of the moving part moved by the servo device; It consists of a signal processing device that calculates the distance to the measurement target surface from the deviation signal, the displacement signal from the displacement measurement device, and the angle between the optical axis of the optical axis incident on the measurement target surface and the optical axis of the focusing optical system. The optical distance measuring device is characterized by:

The present invention will be described below based on embodiments shown in the drawings.

In FIG. 1, the entire measuring device is within a frame surrounded by a two-dot chain line A, and the surface of the object to be measured relative to this is indicated by reference numeral 5.

The measuring device first includes a light source 1, a lens 2, and an optical system 3 arranged at a constant interval.
An incident light side consisting of a required number of mirrors 4, a mirror 11 that takes the reflected light of a minute spot light on the surface 5 of the measuring object on the optical axis 8, an optical system 12, an imaging lens 13, and a deviation measuring device 14. a light-receiving side consisting of a light receiving side, a moving device 18 that operates a moving part in the measuring device indicated by 21 (shaded area) in the figure based on the deviation signal 17 from the deviation measuring device 14, and the moving part 2.
1, a deviation signal from the deviation measuring device 14, a displacement signal from the displacement measuring device 19, an optical axis incident on the surface of the object to be measured, and an optical axis of the condensing optical system. It consists of a signal processing device 22 that calculates the distance to the surface of the object to be measured from the angle formed by the object.

On the movable portion 21, an optical system 3 on the incident light side, a mirror 11 on the light receiving side, an optical system 12, and an image rotation device 27 as necessary are mounted.

Therefore, the optical system 3 is configured such that the surface 5 of the object to be measured is from P ₀ to
In order to prevent an increase in error due to focal deviation by ensuring that the focal position of the light source 1 by the lens 2 is always located near the surface 5 of the object to be measured even if there is a large displacement such as _P 0 ', for example, as shown in FIG. As shown, it is composed of two prisms 30 and 31, one prism 30 is fixed to the above-mentioned movable part 21, and the other prism 31 can be moved compensatingly (described later) in accordance with the displacement of the object to be measured. There is. This prism 3
A lens can be used instead of 0.31.
At this time as well, one lens is fixed to the movable part 21, and the other lens is allowed to move freely for compensation.

The apparatus according to the present invention is roughly constructed as described above, but to explain the functions and relationships between each part of the apparatus using an operational example, the light emitted from the light source 1 is focused onto the surface 5 of the object to be measured. After passing through a lens 2 that connects the two, it passes through an optical system 3.

The optical system 3 ensures that the focal position of the light source 1 by the lens 2 is always in the vicinity of the measurement object surface 5 even if the measurement object surface 5 is largely displaced, thereby preventing an increase in errors due to focal position deviation. For this purpose, for example, as shown in FIG. 2, two prisms 30 and 31 are used. The prism 30 is fixed to the movable part 21 and moves together with the movable part 21, and the prism 31 compensates for the change in the length of the optical axis 8 due to the displacement of the surface 5 of the object to be measured. It moves so that the optical distance between the object surfaces 5 becomes constant. For example, if the moving part 21 is controlled so that the optical axis 9 of the light receiving part substantially coincides with the intersection of the optical axis 8 and the surface 5 of the object to be measured, the prism 31 will move by d/2sin, where the moving distance of the moving part 21 is d. Move the part 21
You can move it against.

The light that has passed through the optical system 3 is properly positioned by a mirror 4 and then focused on the surface 5 of the object to be measured.

On the other hand, the optical axis 9 of the mirror 11 and optical system 12 of the light receiving system, which the moving part 21 moves with, is the optical axis 8.
If the spot light P ₀ on the surface 5 of the object to be measured intersects with the spot light P ₀ while maintaining the same angle as After entering and passing through the optical system 12, the position 15 of the deviation measuring device 14 is determined by the imaging lens 13.
image is formed. The optical system 12 has the same function as the optical system 3. When the surface 5 of the object to be measured is displaced by a minute amount △r to the position 6 and P ₀ moves to P, if the optical axis 9 also follows, the moving part 21 will be △
It is necessary to move by d, but if Δr is a small amount, even if the moving part 21 does not move, the point imaged on the deviation measuring device 14 of point P will be point 16 as shown on the optical axis 10. Therefore, the displacement Δd by which the moving part 21 should move is detected by the deviation measuring device 14, and the deviation signal 17 Δd is obtained.

On the other hand, the displacement signal 20 d ₀ is obtained from the displacement measuring device 19 that measures the length d ₀ of the base of the triangle formed by the optical axis 9 and the optical axis 8 of the moving device 21 , and the deviation signal 17 and the displacement signal 20 are obtained. is input to the signal processing device 22, and from the relationship r=(d ₀ +△d)/tan, P
The distance r to a point can be measured.

When the surface 5 of the object to be measured moves significantly to the position 7 and the P ₀ point moves to P ₀ ', the deviation measuring device 1
The deviation signal (Δd signal) 17 from 4 is the mobile device 1
8, the movable portion 21 is moved so that the deviation signal 17 becomes approximately 0 (zero).

The light source 1 can be, for example, a HeNe laser, and the deviation measuring device 14 can be, for example, a linear array, but the invention is not limited to these.

In the figure, reference numeral 23 indicates an external signal, 24 indicates a measurement signal, and 25 indicates a state in which the mirror 11 has moved.

Figure 3 is a view taken in the - direction arrow of Figure 1.
It is also possible to tilt the measuring device so that the optical axes 8 and 9 in FIG. 1 form a required angle θ with respect to the surface 5 of the object to be measured.

It is also possible to change this angle θ, but in this case, the point 1 imaged on the deviation measuring device 14
If the moving direction of the 5th, 16th, etc. deviation signal 17 changes due to a change in the angle θ, measurement becomes difficult, but such a problem can be solved by interposing the image rotation device 27 between the optical system 12 and the deviation measuring device 14. This can be solved by

This image rotation device 27 can be realized, for example, by using a prism 28 as shown in FIG.

That is, the image direction 32 of the incident light ray 29 is
8 is rotated by θ/2, the image direction 34 of the emitted light beam 33 is rotated by θ.

As described above, according to the device of the present invention, the distance to the object to be measured can be measured with high precision even if the object is largely displaced, and this can be automatically measured in a non-contact state. .

[Brief explanation of the drawing]

FIG. 1 shows an example of the device according to the present invention, FIG. 2 shows a specific configuration example of the part 3 in FIG. 1, FIG. 3 is a view taken from FIG. code 2
A specific example of the configuration of seven parts is shown.

Claims (1)

[Claims] 1. A light source that emits spot light, a lens that receives the spot light from the light source and forms a minute spot light on the surface to be measured, and an optical distance between the lens and the surface to be measured. An optical system on the incident light side consisting of a fixed and movable prism or lens, and a fixed angle to the optical axis from the optical system to capture reflected light from a minute spot light on the surface of the object to be measured. A condensing optical system consisting of an optical system consisting of a condensing mirror and a fixed and movable prism or lens; a deviation measuring device that optically measures the deviation of the light up to a minute spot light, and a moving part of the measuring device in which the optical system on the incident light side and the condensing optical system are mounted is moved based on the deviation. a servo device, a displacement measuring device that measures the moving distance of the moving part, a deviation signal from the deviation measuring device, a displacement signal from the displacement measuring device, an optical axis incident on the surface of the object to be measured, and a condensing optical system. An optical distance measuring device comprising: a signal processing device that calculates a distance to a surface to be measured from an angle formed with an optical axis. 2. A light source that emits spot light, a lens that receives the spot light from the light source and forms a minute spot light on the surface to be measured, and fixation and movement to keep the optical distance between the lens and the surface to be measured constant. An optical system on the incident light side consisting of a flexible prism or lens, and a fixed mirror that maintains a certain angle to the optical axis from the optical system and focuses the reflected light from a minute spot light on the surface of the measurement target. and a condensing optical system consisting of an optical system consisting of a movable prism or lens, and a light spot from the intersection of the optical axis of the condensing optical system and the optical axis on the incident light side to a minute spot light on the surface of the object to be measured. a deviation measuring device that optically measures a deviation; a servo device that moves a movable part of the measuring device on which the optical system on the incident light side and the condensing optical system are mounted based on the deviation; A displacement measuring device that measures the moving distance of the part, a deviation signal from the deviation measuring device, a displacement signal from the displacement measuring device, and an angle between the optical axis incident on the surface of the measurement target and the optical axis of the condensing optical system. The optical distance measuring device consists of a signal processing device that calculates the distance from the surface to the surface to be measured; An image rotation device is provided in front of the deviation measuring device so as to change the angle formed with a certain reference plane, thereby preventing rotation of the image in the deviation measuring device due to rotation of the plane. Optical distance measuring device.