JPS61217716A - Apparatus for obtaining projection light using laser light - Google Patents

Abstract

PURPOSE:To obtain a projection light without discontinuity, by producing a sector-shaped diffusion beam with a single cylindrical convex reflection surface provided on a prism. CONSTITUTION:After diffused slightly with a concave lens 2, a light beam of a laser light source 1 is converged to focus on a projection surface with a convex lens 3 and diffused at a wide range only in one direction with a prism 4 to obtain a sector beam 5 while a linear projection light 7 is obtained on a projection surface. In this case, out of the laser beams 9 incident along the optical axis 10 of the prism 4, the beam incident into the left incident surface 11 is refracted to the right and after totally reflected on the right side 14, it is reflected again on a front reflection surface 16 hitting the right half of a cylindrical reflection surface 18, where it is reflected in diffusion and further refracted on a radiation surface 17 at the front center to be radiated left in front of the prism. The light incident into the right incident surface 12 is likewise radiated right in front of the prism via the left side 13, the left front reflection surface 15, the cylindrical reflection surface 18 and the radiation surface 17 at the front center.

Description

Detailed Description of the Invention (Industrial Field of Application) The present invention relates to a device that uses a laser beam to obtain a focused beam of light on a distant wall, etc. It can be used for varnishing equipment.

<Problems to be Solved by the Invention> The present inventor has proposed the following patent application in Japanese Patent Application No. 58-71746
No. 196,411), etc., propose an invention in which a laser beam is reflected at a wide range of angles by a cylindrical reflecting surface to obtain a single beam of light on a wall surface or the like. Although this invention has the advantage that the intensity distribution of the projected light beam can be determined arbitrarily depending on the design of the curved surface of the cylindrical reflecting surface, it is difficult to manufacture the curved surface, and the laser beam is diffused by the left and right reflecting surfaces. Since the left and right light beams are obtained by using the same method, the reflecting surface must be manufactured with high precision in order to ensure that the left and right light beams are perfectly aligned, which has the disadvantage of increasing manufacturing costs.

SUMMARY OF THE INVENTION An object of the present invention is to provide an apparatus for obtaining a projected light beam using a laser beam, which solves all of these drawbacks at once.

Means for Solving Problems> The device of the present invention includes a diffused laser beam generator, a convex lens for focusing the laser beam on a projection surface, and a device for directing light passing through the convex lens in a predetermined direction. a prism for wide-angle diffusion, the prism having a first boundary plane having a predetermined angle with respect to the optical axis of the incident laser beam, and a second boundary plane facing the light projection surface and perpendicular to the direction of the optical axis; A second boundary plane, a cylindrical convex reflective surface provided behind the second boundary plane, and a reflective surface that guides the incident light of the first boundary plane to the cylindrical convex reflective surface. This is a device that uses laser light to obtain a projected light beam.

In the above-described diffused laser beam generating device, the output beam of the laser light source itself is diffused, and the output beam is diffused by a concave lens, a convex mirror, or the like.

Further, a concave mirror is also an equivalent means for a convex lens for focusing a laser beam on a projection surface.

<Example) FIG. 1 shows an overall configuration diagram of an embodiment of the present invention.

The light beam from the laser light source 1 is slightly diffused by a concave lens 2, then converged by a convex lens 3 so as to be focused on the projection surface, and diffused in only one direction at a wide angle by a prism 4 to obtain a fan-shaped beam 5. A linear projection line 7 is obtained on the projection surface 6.

Figure 2 shows a perspective view of the prism 4.The overall shape is a triangular prism with flat upper and lower surfaces, a square front part and a triangular rear part, and is symmetrical with respect to the optical axis 10 of the incident laser beam. be. The rear boundary plane 11,12 has an inclined surface at an angle .theta. to the optical axis 10 and serves as the entrance surface for the laser beam. The left and right boundary planes 13, 14 of the front part are planes substantially parallel to the optical axis 10 and serve as the initial total reflection surfaces of the incident light beam. The front boundary plane is a plane perpendicular to the optical axis 10, and mirror surfaces 15 and 16 are formed at both left and right ends thereof, and serve as a second reflection surface for the incident light beam. The front central portion 17 becomes a radiation surface for the laser beam to the outside. A cylindrical convex reflective surface 18 is formed behind this front center portion 17. That is, a space 20 is formed, which is composed of a plane 19 parallel to the radiation surface 17 and a cylindrical surface 18 whose axis is on a plane perpendicular to the optical axis 10 and perpendicular to the fan-shaped beam 5 (FIG. 1). The cylindrical surface 18 is a mirror surface.

FIG. 3 shows the optical path of the prism 4. Of the laser beam 9 incident along the optical axis 10, the light incident on the left entrance surface 11 is refracted to the right, totally reflected on the right side surface 14, and then reflected again on the front reflection surface 16 to form a cylindrical beam. The light hits the right half of the reflection surface 18, is diffusely reflected there, is further refracted by the radiation surface 17 at the center of the front surface, and is radiated to the left front of the prism. The light incident on the right incident surface 12 of the laser beam 9 is similarly transmitted to the left side surface 13 . Left front reflective surface 15, cylindrical reflective surface 18. The light is emitted to the right front through the radiation surface 17 at the center of the front surface.

Next, the intensity characteristics of the projected light beam obtained by the present invention will be explained.

A computer simulation was performed for a case in which a laser beam having an intensity distribution characteristic shown by curve a in FIG. 4 and having passed through a circular aperture shown in FIG. 4 was incident on the prism 4 and projected onto the wall surface 6. As shown in FIG. 4, consider a plate-shaped portion CI+C2+'---.C1B cut parallel to a vertical plane C passing through the optical axis and at equal intervals.

As shown in Fig. 5, the light beams projected by each part are dl,
d2. ...dlB. Note that the left and right ends of the laser beam are not effectively reflected within the prism and disappear. The center part c1, where the laser beam intensity is highest, is emitted to the farthest point of the light beam, and the length of the light beam is the largest.On the other hand, the end part CI8, where the laser beam intensity is the smallest, is the farthest part of the light beam. It was confirmed that the length of the projected light beam was the smallest when it was emitted toward the center, and that the intensity distribution of the projected light beam was well balanced as a whole.

FIG. 6 shows another embodiment of the prism of the present invention.

This embodiment differs from the one shown in FIG.
The reflective surfaces 13A and 14A on both the left and right sides are not parallel to the optical axis 10.

The prism 4 of the present invention is not limited to the shape of the above-mentioned embodiments, but can be implemented with various modifications. The angle θ that the first boundary plane, which is the incident surface, makes with the optical axis is not limited to an acute angle, but may be an obtuse angle. In that case, the left half of the laser beam is refracted to the left, and the right half is refracted to the right. do.

Moreover, the reflective surface is not limited to the two-time reflection shown in the embodiment, but can be implemented by one-time reflection or three or more reflections.

Furthermore, the shape may not be symmetrical with respect to the optical axis, but may be such that all of the incident laser beam is refracted in one direction.

Effects> According to the present invention, a 1 fil prism can produce a strong and sharp projected light line with a total length of several tens of meters and a line width of 4.0 ms+ or less.

In addition, since a fan-shaped diffused beam is obtained using a single cylindrical reflecting surface, a single perfectly straight light beam with no discontinuities is obtained from the left end to the right end, and the light intensity is almost uniform, resulting in uneven intensity. is small.

[Brief explanation of the drawing]

Fig. 1 is a perspective view showing the entire embodiment of the present invention, Fig. 2 is a perspective view showing an embodiment of the prism of the present invention, and Fig. 3 is a plan view of the prism shown in Fig. 2 and its optical path. Figure, 4th
FIG. 5 is an explanatory diagram of the intensity distribution of the present invention. 6th
The figure is a plan view of another embodiment of the prism of the present invention and its optical path. 1--Laser light source 2-Concave lens 3--Convex lens 4--Prism 5--Fan-shaped beam 6--Light projection surface 7--Light projection line lO--Optical axis 11.12・-・First boundary plane (incidence plane) 13.14
- Reflective surface 15, 16... - Reflective surface 17 - Second boundary plane (radiation surface) 18... Cylindrical reflective surface 20 - Spatial section Patent applicant Yasushi Ozaki Attorney Patent attorney West 1) New map 1

Claims (1)

[Claims] It has a diffused beam generator for laser light, a convex lens for focusing the laser light on a projection surface, and a prism for diffusing light passing through the convex lens over a wide angle in a predetermined direction, and the prism is configured to focus the laser beam on the incident laser beam. a first boundary plane having a predetermined angle with respect to the optical axis; a second boundary plane facing the light projection surface and perpendicular to the direction of the optical axis; and a second boundary plane provided behind the second boundary plane. a cylindrical convex reflective surface with a cylindrical convex reflective surface; and a reflective surface that guides incident light on the first boundary plane to the cylindrical convex reflective surface;
A device that uses laser light to obtain a projected light beam.