JPS59228621A - Slit projector - Google Patents

Abstract

PURPOSE:To make a slit image sharp and reduce a projector in size by providing at least two masks which have openings in a specific shape and of specific size in the traveling direction of light and lenses for forming slit light. CONSTITUTION:When light emitted by a laser diode 2 passes through the 1st- stage mask 15, the mask 15 cuts off diffracted light 25 and the circumference of straight traveling light 23, which generates diffracted light 27 newly. The luminous flux section 28 of the straight traveling light is shaped rectangularly as shown in a figure, and the luminous flux section 29 of the new diffracted light 27 is dispersed around the rectangle. When the light passes through the 2nd-stage mask 16, the mask 16 cuts off the diffracted light 27 to obtain light 23 shown in a figure, so this light is passed through a collimator lens 17 and cylindrical lenses 18 and 19 to be converged linearly, obtaining slit light 30 shown in a figure. Thus, the sharp slit image is projected and the projector is reduced in size.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a slit projector used in a robot's visual sensor, and more particularly to a slit projector that sharpens a projected slit image.

As a visual sensor for robots for work such as welding, there is a shape measurement system that uses the principle of optical sectioning, which determines the cross-sectional shape of the object to be measured based on the degree of deformation of slit light projected from the sensor side. Conventionally, an incandescent light bulb or a laser has been used as the slit light source for the projection light.

However, when these light sources are used, the external dimensions of the light emitting part are large, so the projector becomes large, and the light sources cannot be switched at high speed using electrical signals.

The problem of speeding up switching can be solved by using a laser diode or LED as a light source, but on the other hand, the radiation beam may be diffused due to the light emitting mechanism unique to the laser diode, or the frontage of the light emitting part of the laser diode itself may be Since diffracted light is generated corresponding to the shape of the slit, it has the disadvantage that a sharp slit image cannot be obtained.

The present invention has been made in order to eliminate the above-mentioned drawbacks, and has a light emitting part that houses a light source, and a light emitting part that is arranged at least twice in the traveling direction of light emitted from the light emitting part and has a predetermined shape and dimensions. This relates to a slit floodlight that is equipped with a mask with an aperture and a lens that converges the light that has passed through the mask to create a slit beam.Since the double mask is used to shape the beam cross section of the emitted light, the slit The image can be sharpened,
Furthermore, since a laser diode light source is used, the projector has the advantage of being able to be made compact.

Embodiments of the present invention will be described below with reference to the drawings. 1st
3 to 3 show an embodiment of the present invention, in which reference numeral 1 denotes a lens barrel, 2 a laser diode, 3 a single line connecting the laser diode 2 and a connector 4;
5 is an optical component holder that holds the laser diode 2 in the lens barrel 1; 6 is an optical component holder via a pressing spring 7;
5 a mask holder that supports the front surface; 8 an optical component holder;
11 is an adjustment bolt that drives the presser piece 8; 12 is an adjustment bolt 11;
A rectangular opening 13 with a knife-shaped edge is provided inside the mask holder 6.
．． 14 is attached in a direction perpendicular to the optical axis a, and further inside the lens barrel 1, a collimator lens 17 and a cylindrical lens 18, 19 are arranged in the order shown in the figure from the side closest to the laser diode 2. has been done.

Apertures 13 and 14 of each mask, collimator lens 17,
The cylindrical lenses 18 and 19 are all attached concentrically to the center of the aperture (not shown) of the laser diode 2, that is, the optical axis a passing through the diagonal intersection of the rectangle, and furthermore, the long and short sides of the apertures 13 and 14 of each mask 15 and 16 are attached to the junction surface of the laser diode so that they are parallel to each other in the vertical and horizontal radiation angle directions.

The dimensions of the aperture 13.14 of each mask, that is, the distances between opposite sides of each rectangle, c, d, and e (see FIGS. 2 and 3) are the diffracted light contained in the laser beam that reaches each mask 15.16. In addition, the dimensions of the first-stage mask 15 are set so as to appropriately block the periphery of the light beam that has traveled straight and shape the cross section of the light beam.

The collimator lens 17 is formed by a convex lens having a required focal length, or by a cylindrical lens 18, 19.
is composed of a convex lens having one or both surfaces formed into a cylindrical surface having a required curvature, and the cylindrical surface 20.2
1 are arranged so that the longitudinal directions of their cylinders are orthogonal to each other.

Next, the operation of this device will be explained with reference to FIGS. 4 to 13. The light emitted from laser diode 2 is
The light becomes light having a beam cross section shown in FIG. 6 and enters the first stage mask 15. As shown, the beam cross section is composed of a beam cross section 24 of the rectilinear light 23 diffused into a deformed ellipse and a beam cross section 26 of the diffracted light 25 scattered around the ellipse. Note that FIG. 10 shows the intensity distribution in the cross section of the light beam, and FIG. 4 shows the straight light 13 and the diffracted light 2.
The diffusion range of No. 5 is shown using a solid line f and a broken line g.

When the light passes through the first stage mask 15, the mask 1
5 blocks the diffracted light 25 and the vicinity of the straight light 23, and the blocked straight light 23 generates a new diffracted light 27.

7 and 11 show the cross section and intensity distribution of the light beam after passing through the mask 15.

As shown in the figure, the beam cross section 28 of the straight light is shaped into a rectangle, and new beam cross sections 29 of the diffracted light 27 are scattered around this rectangle.

When the light passes through the second stage mask 16, the mask 16
blocks the diffracted light 21, and the light shown in FIGS. 8 and 12 is obtained. This light is converged linearly through the collimator lens 11 and the cylindrical lenses 18, 19, and then the light shown in FIGS. Slit light 30 shown in FIGS. 9 and 13
get.

Since the double masks 15 and 16 are provided to block the diffracted light and shape the beam cross section, the slit image becomes extremely sharp.

It should be noted that the present invention is not limited only to the above-described embodiments, and it goes without saying that various changes can be made without departing from the gist of the present invention.

Since the slit projector of the present invention has the above-described configuration, it exhibits the following excellent effects.

(D) A sharp slit image can be projected because a double mask is provided to shape the beam cross section.

(ii) By using a laser diode as a light source, the external dimensions of the light emitting part are reduced, and the projector can be configured in a compact size.

(To) High-speed switching can be performed for the same reason as in item (n).

0 Since the light beam is shaped using a double mask, the structure is simple and it can be placed in a narrow space.

[Brief explanation of the drawing]

1 to 3 show embodiments of the present invention, FIG. 1 is a cutaway side view of the slit floodlight, and FIGS. 2 and 3 are views taken from the ■-■ direction and the ■-m direction in FIG. 1. Enlarged arrow views, especially the front view of the mask opening, Figures 4 to 1
Fig. 3 is an explanatory diagram of the operation of the floodlight shown in Fig. 1, Fig. 4 is a side view showing the arrangement of main parts, and Fig. 5 is a diagram showing the arrangement of the main parts.
- Arrow view from direction, Figure 6, Figure 7, Figure 8, Figure 9
The figures are Vl-■ direction and vn-v direction in Fig. 4, respectively.
10, 11, 12, and 13 are 6, 7, 8, and 9, respectively. FIG. 3 is an intensity distribution diagram of each beam cross section shown in FIG. In the figure, 2 is a light emitting part, 13.14 is an opening, and 15.16 is a mask. Patent applicant Ishikawajima Harima Heavy Industries Co., Ltd. Patent applicant Omnipac Co., Ltd.

Claims (1)

[Claims] 1) A light-emitting section that houses a light source, a mask that has 611 openings that are arranged at least twice in the traveling direction of the light emitted from the light-emitting section and have a predetermined shape and dimensions, and a light that has passed through the mask. A slit floodlight characterized by comprising a lens that converges light to produce light.