JP2892440B2 - Displacement sensor - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a displacement sensor that emits and receives a laser beam and detects the amount of displacement of the surface of a target object by triangulation.

[Prior art] In recent years, factory automation (FA) has been promoted in factories, for example, as a visual sensor for robots that perform welding, deburring, etc., and as a sensor for performing defect inspection, dimension measurement, etc. of products. A displacement sensor is used, and as this type of displacement sensor, there is a displacement sensor that measures the displacement of the surface of a target object in a non-contact manner using an optical triangulation method. Note that such a displacement sensor of the triangulation method has an advantage that the configuration is relatively simple.

In general, this type of displacement sensor emits a light beam projected from a light projecting system equipped with a semiconductor laser, a light emitting diode, etc., to the target object, and uses the diffuse reflected light according to the distance to the target object in the light receiving system. It is configured to obtain the output. Here, the light receiving system is an optical system that collects diffuse reflected light, and a PSD that generates an output corresponding to the position of a condensed spot that is arranged on the imaging surface of the optical system and moves according to the distance to the target object. And the distance to the target object is calculated by a triangulation method based on the output of the position detection sensor. The two-dimensional shape of the surface of the target object is obtained by scanning the light beam on the surface of the target object in the light projecting system.

[Problems to be Solved by the Invention] By the way, safety standards such as a laser emission warning are set for laser products of Class 3A, 3B, and 4 in the JIS standard. In the case of using a laser for the light emitting system, a laser emission warning light is provided. However, this type of laser emission warning light must be provided at a position where it will not be exposed to laser radiation, and the lighting state of this laser emission warning light may not be visible. For example, if the laser emission warning light is provided on the back side of the laser emission surface of the displacement sensor, and if the worker is working in a place where The radiant warning light cannot be seen.

The present invention has been made in view of the above points, and an object of the present invention is to provide a displacement sensor that can confirm laser radiation even in a place where it is exposed to laser radiation.

Means for Solving the Problems In order to achieve the above-mentioned object, the present invention sets the both ends of the scanning range of the laser beam on the target object a predetermined time before the emission of the laser beam in synchronization with the laser emission warning light. A mark display device indicated by a light mark by visible light is provided.

In the case of a displacement sensor that is not a scanning type, a mark display device is provided that indicates the emission position of the laser beam on the target object by a visible light mark a predetermined time before the emission of the laser beam in synchronization with the laser emission warning light. Good. In this displacement sensor, the laser beam emitted from the light projecting system and the visible light emitted from the mark display device may be mixed by a half mirror and emitted in the same direction.

[Operation] By providing the mark display device as described above, the present invention performs laser radiation display with an optical mark in the same direction as laser radiation, and confirms laser radiation even in a place where it is exposed to laser radiation. Is made possible.

[Embodiment] FIGS. 1 to 3 show an embodiment of the present invention. The laser scanning displacement sensor of the present embodiment emits a laser beam to the target object 1 and scans the surface of the target object 1 with the laser beam, and collects the reflected light of the laser beam from the target object 1. A light-receiving system 30 that obtains an output corresponding to the position of a condensed spot that moves in accordance with the distance from the target object 1 by a position detection sensor 32 disposed on the illuminated imaging surface, and in synchronization with the laser emission warning light 3 A mark display device 40 is provided which indicates both ends of the scanning range of the laser beam on the target object 1 by a visible light mark 2 on the target object 1 a predetermined time before the emission of the laser beam.

The casing 10 of the displacement sensor has a light projecting window 11 for the light projecting system 20 and the mark display device 40 and a light receiving window 12 for the light receiving system 30 formed on one surface.

The light projecting system 20 includes a laser 21 such as a semiconductor laser, a scanning mirror 22 which is appropriately rotated by a driving system, a light projecting lens 23 and a mirror disposed between the laser 21 and the scanning mirror 22.
It consists of 24. Here, the light projecting lens 23 is a laser
The mirror 24 is provided to reduce the restriction on the positional relationship between the laser 21 and the scanning mirror 22, and the relatively small internal space of the housing 10 is effective. The purpose of this is to reduce the size of the housing 10. In the light projecting system 20, a laser beam is emitted to the target object 1 through the light projecting window 11 of the housing 10, and the laser beam is scanned on the surface of the target object 1 according to the rotation of the scanning mirror 22.

The light receiving system 30 is a light receiving window that is diffusely reflected on the surface of the target object 1.
An optical system 31 for condensing laser light incident through 12,
One-dimensional position detection sensor arranged on the image plane of the optical system 31
It consists of 32. The position detection sensor 32 is formed of a PDS or the like, and generates an output corresponding to the position of the condensed spot formed on the imaging surface of the optical system 31. Note that, based on the output of the position detection sensor 32, the scanning mirror 22 is triangulated.
The distance between the object and the target object 1 is obtained, and the displacement of the surface of the target object 1 is detected based on the distance.

The mark display device 40 includes a pair of light emitting elements 41a and 41b including a light emitting diode or the like that emits visible light, and the light emitting elements 41a and 41b.
It is composed of light projecting lenses 42a and 42b that convert the light from 1b into parallel rays. The light emitting element 41 and the light projecting lens 42 that constitute each set of the mark display device 40 are disposed on both sides in a direction orthogonal to the scanning direction of the scanning mirror 22, and are located at both ends of the scanning range of the laser beam on the surface of the target object 1. The light mark 2 is displayed.

Furthermore, in this type of displacement sensor, as described above, the JI
Since it is specified in S that a warning is issued at the time of laser radiation, a laser radiation warning light 3 is provided to cope with this, and the laser radiation warning light 3 is provided on the back surface of the housing 10. The laser emission warning light 3 is designed to be turned on a predetermined time before laser beam emission based on the FDA standard. Now, assuming that a laser beam is emitted as shown in FIG. 3 (c), the laser emission warning lamp 3 is turned on as shown in FIG. 3 (b).

By the way, the optical mark 2 by the mark display device 40
Is displayed as shown in FIG. 3E, for example, in conjunction with turning on / off the power supply as shown in FIG. 3A, or as shown in FIG. However, in the former case, lighting of the light mark 2 does not give a laser radiation warning, and in the latter case, the light mark 2 is displayed on the surface of the target object 1. By the time the laser has already been emitted, there is no room to avoid being exposed. Therefore, the light mark 2 is displayed in synchronization with the laser emission warning light 3 as shown in FIG. In this way, the laser emission warning is given by the light mark 2
Thus, the laser scanning range can be known from the optical mark 2.

In the above description, the laser scanning displacement sensor has been described. However, as shown in FIGS. 4 and 5, if the scanning of the laser beam is not performed as shown in FIGS. Is mixed with the laser beam from the light projecting system 2 so that the visible light is emitted in the same direction as the laser beam. Can be displayed on the surface.

[Effects of the Invention] As described above, in the present invention, both ends of the scanning range of a laser beam are indicated by visible light marks on the target object a predetermined time before the emission of the laser beam in synchronization with the laser emission warning light. Since the mark display device is provided, the laser radiation display is performed by the optical mark in the same direction as the laser radiation, so that the laser radiation can be confirmed even in a place where the laser radiation is exposed.

In addition, in the displacement sensor which is not a scanning type, a mark display device is provided in which a laser beam emission position is indicated by a visible light mark on a target object a predetermined time before the emission of the laser beam in synchronization with the laser emission warning light, If the laser beam emitted from the light projecting system and the visible light emitted from the mark display device are mixed by a half mirror and emitted in the same direction, the laser mark is displayed in the same direction as the laser emission. The laser radiation can be confirmed even in a place where the laser radiation is exposed.

[Brief description of the drawings]

FIG. 1 is an explanatory view showing a schematic configuration of an embodiment of the present invention, FIG. 2 is an explanatory view showing a laser beam radiation state of the above, FIG. 3 is an operation explanatory view of the same, and FIG. FIG. 5 is an explanatory diagram showing a schematic configuration of the embodiment, and FIG. 5 is an explanatory diagram showing a radiation state of the laser beam in the embodiment. 1 is a target object, 2 is a light mark, 3 is a laser emission warning light,
20 is a light projecting system, 25 is a half mirror, 30 is a light receiving system, 32 is a position detection sensor, and 40 is a mark display device.

Claims (2)

(57) [Claims] A projection system for emitting a laser beam to a target object and scanning the laser beam on a surface of the target object;
A light receiving system that obtains an output corresponding to the position of a converging spot that moves according to the distance to the target object by a position detection sensor disposed on an image forming surface that condenses the laser beam reflected by the target object, and a laser. A displacement sensor comprising: a mark display device that indicates both ends of a scanning range of a laser beam on a target object with visible light marks on a target object a predetermined time before the emission of the laser beam in synchronization with the radiation warning light. 2. A light projecting system for emitting a laser beam to a target object, and a position detection sensor disposed on an image forming surface on which the reflected light of the laser beam by the target object is collected according to the distance to the target object. A light receiving system that obtains an output corresponding to the position of the moving condensing spot, and a laser beam emission position that is synchronized with the laser emission warning light and the laser beam emission position on the target object with a visible light And a visible light emitted from the mark display device is mixed by a half mirror and emitted in the same direction.