JPH01272907A - Optical scanning type displacement sensor - Google Patents

Abstract

PURPOSE:To view the scanning range of a light beam without using any dimming element such as a half-mirror by forming light marks of visible light at both end positions of the scanning range on the surface of the object body of a projection system. CONSTITUTION:The projection system 20 projects and scans a light beam on the surface of the object body 1. A photodetection system 30 has a position detection sensor 32 arranged on the image formation surface where the diffuse reflected light of the light beam by the object body 1 is converged and outputs an electric signal corresponding to the position of a convergence spot moving according to the distance to the object body 1. Then a mark forming device 40 is provided which forms the light marks 2 of visible light at both end positions of the scanning range on the surface of the object body 1 of the projection system 20. Consequently, the light beam photodetected by the position detection sensor 32 and the light marks 2 for viewing need not be mixed and the scanning range of the light beam can be viewed without using any dimming element such as a half-mirror.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is applicable to FA, which is used as a visual sensor for robots that perform welding, deburring, etc., and as a sensor for product defect inspection, dimension measurement, etc. The present invention relates to an optical scanning displacement sensor that measures the two-dimensional shape of the surface of a target object using an optical triangulation method.

[Conventional technique vk1 In recent years, factory FA (7 Actory Automation)
There is a demand for displacement sensors on production lines that can position objects and recognize the presence or absence of objects using information about the distance to the object. As displacement sensors that meet these demands and detect the distance to a target object without contact, there are six types that optically measure the distance to a target or object, and those that use triangulation are relatively sophisticated. It has been put into practical use because it is simple.

Generally, this type of displacement sensor, as shown in FIG.
A light beam projected from a light projection system 20 equipped with a semiconductor laser, a light emitting diode, etc. is irradiated onto the target object 1, and the diffusely reflected light is collected by a light receiving light T system 31.
? ``The condensed spot formed on the imaging plane of system 31 is PSD
The position detection sensor 32 is configured to receive the light.

The position detection sensor 32 can obtain an electrical signal corresponding to the position of the focused spot, and based on this electrical signal, the distance to the target object 2 is calculated by triangulation.

On the other hand, in order to obtain the two-dimensional shape of the surface of the target object 1, the light projection system 2 is configured to scan the light beam on the surface of the target object 1.
It has been considered to provide a scanning mirror 22 at 0. In this case, the two-dimensional shape of the scanning line on the surface of the target object 1 can be obtained from the irradiation direction of the light beam by the scanning mirror 22 and the distance to the target object 1 obtained by the position detection sensor 32. .

In a displacement sensor that scans the surface of the target object 1 with such a light beam, light other than visible light is used as the light irradiated from the light projection system 20 to the target object 1 in order to reduce the influence of disturbance light. In particular, it is common to use infrared radiation. If light other than visible light is used as the light beam, the scanning range on the surface of the target object 1 cannot be visually observed, so a problem arises in that it is not possible to confirm whether the light beam is irradiating the target object 1. . One possible way to deal with this problem is to use visible light that is sufficiently stronger than the ambient light for the light beam, but in this case, the light beam cannot be viewed directly, so the solution to the problem is It doesn't become.

In order to solve these problems, as shown in Fig. 14, light other than visible light received by the position detection sensor It is considered that the mixed light can be used to form a light beam.

Problems to be Solved by the Invention However, with the above configuration in which the light beam is a mixture of visible light and non-visible light, the light beam 11 is formed through the half mirror 26. , each light emitting element 21.
Since the output light from 27 is attenuated by the bar 7 mirrors: 3--26, it is necessary to increase the output of the light emitting elements 21 and 27 in order to obtain a light beam of a predetermined intensity. As a result, power consumption increases, and it is necessary to select a light emitting element 21, 27 with a large output.The present invention aims to solve the problems mentioned above. The present invention aims to provide an optical scanning displacement sensor that allows the scanning range of a light beam to be visually observed without using a light attenuation element such as the above.

[Means for Solving #Problems] In order to achieve the above object, the present invention includes a mark forming device that forms optical marks of visible light at both end positions of the scanning range on the surface of the target object of the projection system. We are prepared.

Further, it is desirable that the mark forming device be able to freely adjust the interval between the two optical marks formed on the surface of the target object.

Effect 1 According to the above configuration, the optical mark of the off-visibility is formed at the 1illii end position of the scanning range of the light beam by using the mark formation to 4-dispersion that is separate from the light projection system, so the position detection sensor There is no need to mix the potential beam received by the light beam with a visual optical mark, and the scanning range of the light beam can be visually recognized without using a light attenuation element such as a half mirror.

[Example 11 $1 As shown in FIG. 1 and FIG. 2, a light projecting system 20, a light receiving system 30, and a mark forming device f! A light emitting window 11 that takes out light from the light emitting system 20 and the mark forming device 40, and a light receiving window 12 that introduces light to the light receiving system 30 are installed in one part of the housing 10. It is open on one side.

The light projecting system 20 includes a light emitting element 21 such as a semiconductor laser or a light emitting diode that emits infrared rays, and a scanning system that scans the surface of the target object 1 with light from the light emitting element 21, which is driven by an appropriate drive system to allocate prices. The mirror 22, a light projecting lens 23 and a mirror 24 arranged between the light emitting element 21 and the scanning mirror 22 form an M configuration. The light projection lens 23 is configured to convert the light from the light emitting element 21 into parallel rays, and the mirror 24 changes the direction of the parallel rays. Therefore, due to the presence of the mirror 24, the light emitting element 21
It is possible to reduce restrictions on the arrangement relationship between the scanning mirror 22 and the scanning mirror 22, and by effectively utilizing the relatively narrow internal space of the housing 10, the housing 10 can be downsized. The light beam thus formed is irradiated onto the target object 1 through the light projection window 11 of the housing 10, and the light beam is scanned over the surface of the target object 1 in accordance with the swinging of the scanning mirror 22.

The light-receiving system 30 includes a light-receiving optical system 31 that collects light diffusely reflected on the surface of the target object 1 and introduced into the housing 10 through the light-receiving window 12, and a light-receiving optical system 31 disposed on the imaging plane of the light-receiving optical system 31. It consists of a one-dimensional position detection sensor 32. The position detection sensor 32 is formed of a PSD or the like, and is configured to obtain an electric signal corresponding to the position of a light receiving spot formed on the imaging plane of the light receiving optical system 31. Here, the swinging direction of the scanning mirror 22 and the detection direction of the position detection sensor 32 are arranged to be substantially perpendicular to each other. According to this configuration, since the positional relationship between the scanning mirror 22, the light receiving optical system 31, and the position detection sensor 32 is fixed, by performing triangulation based on the output value of the position detection sensor 32, the scanning mirror 22 By knowing the separation between the target object 1 and the target object 1, the amount of displacement of the surface of the target object 1 can be determined.

By the way, the mark forming device 40 includes a pair of light emitting elements 41
a, 41b, and projecting lenses 42a, 42b disposed in front of the light emitting elements 41a, 41b, and light emitting diodes or the like that emit visible light are used as the light emitting elements 41a, 41b. .

Moreover, the light projecting lenses 42a and 42b are light emitting elements 41a.

The light from 41b is made into parallel rays. Double-light optical element 41a,
41b are arranged on both sides of the scanning mirror 22 in the scanning direction, and the light from the light emitting elements 4.1a and 41b is irradiated onto the target object 1 through the light projection window 11.
On the surface of , there are optical marks 2 at both ends of the scanning range of the light beam.
is set to form. If the distance from the housing 10 to the target object 1 changes, a shift will occur between the scanning range of the light beam and the position of the optical mark 2.
The distance between 0 and the target object 1 is approximately constant, and the purpose of the main optical mark 2 is to confirm that the scanning range of the light beam does not deviate from the target object 1, so some deviation is Almost no problem.

As described above, there is no need to use a half mirror as in the conventional method to indicate the scanning range of the light beam, and the efficiency of using light from the light emitting element 21 is increased, thereby preventing the intensity of the light beam from decreasing. It can be done.

[Example 2] In Example 1, the direction of the light beam forming the optical mark 2 was fixed, but if you want to correct the deviation between the scanning range of the optical beam and the optical mark 2, or when you want to correct the deviation between the scanning range of the optical beam and the optical mark 2, When it is desired to mark outside the range, it may be necessary to change the direction of the light beam forming the optical mark 2.

In order to meet such requirements, in this embodiment, as shown in FIGS. 3 and 4, in the mark forming device 40, light emitting elements 41a, 41b and light projecting lenses 42a, 42 are provided.
The light emitting elements 41a and 41b are placed in the holder 43 that holds the light emitting elements 41a and 41b.
The key to adjust the position of! This is because it has an I camera setup. The holder 43 includes a pair of element supports 44a and 4.4b that hold the light emitting elements 41a and 41b, respectively, a lens support 45 that holds both the light projecting lenses 42a and 42b, and Element support 44 a+ 44
A pair of adjusting screws 46a, 46 for adjusting the position of b, respectively.
b. The lens support 45 has a notch 45a.
are formed, and the tips of the arms 47a, 47b formed on the element supports 44a, 44b are accommodated in the notch 45a. The adjustment screws 46a and 46b are attached to the lens support 4.
5, and the head is connected to the lens support 45.
The leg portion has a length spanning the entire width of the notch portion 45 . In addition, the head side of the legs has a larger diameter,
The tip side has a small diameter, and each adjustment screw 46a, 46b
The small diameter portions of the arms 47a and 47b respectively pass through the arms 47a and 47b,
The end surfaces of the large diameter portions come into contact with the side surfaces of each arm 47a, 47b. Therefore, each llN node screw 4
When 6a and 46b are screwed, each corresponding arm 47a
, 47b are pressed by the 11N joint screws 46a, 46b, respectively, and move upward in FIG. Pressing springs 48a, 48b made of coil springs are attached to the tips of the legs of each adjusting screw 46a, 46b, respectively, and the inner peripheral surface of the notch 45a and each arm 47a, 47b
Pressing springs 48a and 48b are sandwiched between them. Therefore, when the adjusting screws 46a, 46b are retreated, the arms 47a, 47b move downward in FIG. 4 due to the spring force of the pressing springs 48a, 48b.

According to the above configuration, each of the element supports 44a and 44b can be moved relative to the lens support 45 as the adjustment screws 46a and 46b move forward and backward. Therefore, when it is desired to widen the distance between the two light marks 2, as shown in FIG.
If you want to adjust the position of the light-emitting elements 41a and 41b so that they are closer to the inside of 42L+ and narrow the distance between both marks 2, as shown in FIG. 5 (1), Lenses 42a, 42]] and light emitting element 41]
All you have to do is adjust the position ta so that a and 41b are moved outward.

This allows the position of the optical mark 2 to be adjusted in accordance with the scanning range of the light beam. In addition, as shown in FIG. 6, the target object 1
It is also possible to attach the optical mark 2 to the reference position in .

[Example 3] By the way, in Example 1, the light emitting element 2 in the light projection system 1
Although an example is shown in which the mirror 24 is provided in order to change the direction of the light from the casing 10 and effectively utilize the internal space of the casing 10, it is generally possible to downsize the casing 10 or adjust the length of the optical path. Therefore, it may be necessary to change the direction of the light beam. When the direction of the light beam is set to the R node, as shown in FIG.
It is common to use a mirror 25b for the joint, but in such a configuration, the configuration is complicated and the mirror 25b is used.
There is a problem that the arrangement space for a and 25b becomes large.
Furthermore, since the light is reflected by the two mirrors 25a and 25b, there is a problem in that the amount of light is reduced.

Therefore, in this embodiment, as shown in FIGS. 7 and 8, a configuration is disclosed in which a mirror hole 50 that is capable of m-sections of two axes is used.

The mirror holder 50 includes a mirror support 51 that holds the mirror 24 and a support base 52 that holds the mirror support 51. The mirror support 51 is made of a flexible material, such as synthetic resin or metal such as aluminum or brass.

The mirror support 51 includes a base portion 51a and a movable portion 51b, and one surface of the base portion 51a is an inclined surface. The movable part 51. b, and one end of the movable portion 51b is integrally coupled to the base portion 51a at one end in the direction of inclination of the inclined surface. In addition, the base portion 5
An adjustment screw 53 is screwed into 1a, and the tip of the adjustment screw 53 comes into contact with the back surface of the movable portion 51b. The mirror 24 is attached to the surface of the movable portion 511J, and by screwing the adjusting screw 53, the movable portion 51b can be pressed by the adjusting screw 53. Further, when the adjustment screw 53 is moved back, the movable portion 51b returns to its original position due to the elasticity of the material of the mirror support 51. In this way, as the adjustment screw 53 moves back and forth, the free end of the movable part 51 changes the distance from the base part 51a, as shown in FIG. can be adjusted. As the adjusting screw 53 moves forward and backward, the mirror 2
4 angles can be adjusted. Here, the movable part 51
b is desirably formed in such a shape that the free end is closer to the base portion 51a than the fixed end when not receiving the pressing force from the adjusting screw 53.

The base portion 51a has a shaft portion 51c protruding from the side opposite to the inclined surface, and the shaft portion 51C has a notched groove 54 on the same side of the base portion 51a where the adjustment screw 53 is inserted. It is formed. This shaft portion 51c is inserted into a circular holding hole 52a formed in the support base 52.
An adjustment section 55 is inserted into the. The adjustment unit 55 is an operating unit 5 that is rotated using a jig such as a screwdriver.
5a, and a shaft pin 55b that projects eccentrically with respect to the operating portion 55a. The shaft pin 55b has the above-mentioned notch groove 54.
It has a diameter approximately equal to the width of the cutout groove 54 and is inserted into the notch groove 54 . Here, the center line of the operating portion 55a is arranged to pass through the center of the holding hole 52a, and the operating portion 55a is arranged so as to pass through the center of the holding hole 52a.
When a is rotated, the center line of the shaft pin 55b aligns with the holding hole 52.
It will swing left and right with respect to the center of a. That is,
As shown in FIG. 10, the shaft portion 51c rotates as the operating portion 55a rotates, and the angle of the mirror 24 is approximately perpendicular to the direction in which the angle of the mirror 24 is adjusted by the adjusting screw 53. can be adjusted.

According to the above configuration, after first adjusting the angle of the mirror 24 with the adjustment screw 53, it is sufficient to insert the adjustment part 55 into the support base 52 and rotate the shaft part 51c.
Since it is possible to adjust the angle of the mirror 24 in two directions using the and adjustment section 55, the configuration is simpler and space-saving compared to the case where two mirrors are used, and the amount of attenuation of light due to reflection is also reduced. It can be reduced. Further, since the adjustment screw 53 and the adjustment section 55 are exposed in the same direction, when the device is housed in a housing, the adjustment section can be faced on the same side, making adjustment work easier.

In the above configuration, the movable part 5 is attached to one end of the inclined surface of the base part 51a.
1b, but as shown in FIG. 11, the movable portion 51b may be connected to the center of the inclined surface.

[Effects of the Invention] As mentioned above, the present invention is equipped with a mark forming device that forms visible light marks at both end positions of the scanning range on the surface of the target object of the light projection system, and the light beam Since visible light marks are formed at both end positions of the scanning range of This allows visual inspection of the scanning range of the light beam.

As a result, there is no need to increase the light emitting output of the light emitting element that forms the light beam, and the structure can be made economically.

[Brief explanation of the drawing]

FIG. 1 is a schematic perspective view showing a first embodiment of the present invention, FIG. 2 is an explanatory diagram of the same operation as above, FIG. The partial plan view, #S5 figure and Figure 6 are operation explanatory diagrams of the same as above, and Figure 7 is Embodiment 3 of the present invention.
FIG. 8 is an exploded perspective view of the main parts of the same as above, FIGS. 9 and 10 are explanatory views of the same as the above, FIG. 11 is a side view of the main parts showing the other side of the above, FIG. 12 is a schematic configuration diagram showing a comparative example to the above, FIG. 13 is a schematic configuration diagram of an optical scanning displacement sensor according to the present invention, and FIG. 14 is an operation explanatory diagram showing a conventional example. DESCRIPTION OF SYMBOLS 1... Target object, 2... Light mark, 20... Light emitting system, 30... Light receiving system, 32... Position detection sensor, 4
0...Mark forming device. \J Figure 11b] Figure 12 25a 5b Figure 13

Claims (2)

[Claims] (1) A projection system that irradiates a light beam so as to scan the surface of the target object, and a position detection sensor placed on the imaging plane that focuses the diffuse reflection light of the light beam from the target object. A light receiving system outputs an electrical signal in response to the position of a condensed spot that moves according to the distance from the target object, and a visible light optical mark is formed at both ends of the scanning range of the light emitting system on the surface of the target object. What is claimed is: 1. An optical scanning displacement sensor comprising a mark forming device. (2) The optical scanning displacement sensor according to claim 1, wherein the mark forming device is capable of adjusting the distance between the two optical marks formed on the surface of the target object.