JPS6244709A - Optical system for laser beam - Google Patents

Abstract

PURPOSE:To reduce reflection loss on lens surfaces greatly and to obtain spot light with high brightness by composing an optical system of only two single lens elements. CONSTITUTION:A laser light generator 5 emits an He-Ne laser beam of 6,328Angstrom in wavelength. The laser beam is changed in direction by 180 deg. through two mirrors 6 and 7, diverged slightly by a rear lens 8, and the converged by a front lens 9 to project spot light on a target at distance (10-100m). Numbers 1-4 are surface numbers given to the lens surfaces from the front in order. Respective constants of the lenses are determined most preferably as shown in equations and may be varied within a range of + or -10%. The reflected light of the laser beam from a half-mirror 10 becomes upward perpendicular output light 12 and the transmitted light is reflected by a rear mirror 11 and further reflected by the half-mirror 10 become downward perpendicular output light 13.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to an optical system for a laser beam, and more specifically, it is an optical system for projecting a spot light to a distant place (IQm=lQOm) using visible C-the light. Regarding optical systems.

<Prior Art> Conventionally, a lens composed of three or four lenses has been used to correct aberrations.

<Problems to be Solved by the Invention> The present invention focuses on the fact that a laser beam has an intensity distribution characteristic in which it is strong in the center and weak in the periphery, and actively utilizes the aberration of the lens to create a simple lens. In configuration, lOm
The aim is to maintain a nearly uniform beam diameter over a wide range of several tens of meters without adjusting the focus, and to obtain a sharper spot light than conventional ones.

For optical systems that use laser beams, it is difficult to input the laser emitting mechanism into a computer, so computer simulation data and experimental values do not necessarily match regarding the beam diameter at a distance. [Means for solving the problems] Fig. 1 shows a block diagram of the present invention.

The laser beam generator 5 has a wavelength of 6328 angstroms.
Outputs e-Ne laser beam. 2 mirrors 6.7
After the direction is changed by 180°, the beam diameter is slightly diffused by the rear lens 8, and then the light is condensed by the front lens 9, and the spot light is projected onto a distant object (10 m to 100 m). Numbers 1, 2, 3.4 are surface numbers assigned to the lens surfaces in order from the front. The lens constants shown in the table below are most preferable, and it is possible to increase or decrease the numerical values within the range of ±10%.

Table 1 <Example> FIG. 2 shows the configuration of a vertical value according to an embodiment of the present invention.

The laser beam generator 5 is a He-Ne laser with an output of 0.5 mW, the intensity distribution characteristics are single mode, the output beam diameter is 0.58 mm, and the beam divergence angle is 1. 6
5 mrad, wavelength 6328 angstroms.

This laser beam is reflected by a 90° reflection mirror 6.7.
The direction of the light is changed by 0°, the light is slightly diffused by a concave lens 8 disposed at the rear, and is focused on an object by a convex lens 9 disposed at the front. The constants of the concave lens 8 and the convex lens 9 are shown in Table 1. The laser beam is further reflected by a half mirror 10 and its reflected light becomes upward vertical output light 12, and the transmitted light is reflected by a rear mirror 11 and reflected by the half mirror 10 to become downward vertical output light 13.

In another embodiment of the present invention, the horizontal value can be obtained by reflecting the upper vertical output light 12 shown in FIG. 2 by 90 degrees with a rotating mirror.

Furthermore, as another embodiment, a lens system may be disposed directly in front of the laser beam generator 5 to obtain a laser spot projector that outputs a laser beam in the horizontal direction, vertical direction, or any other arbitrary direction.

Effect> Table 2 shows actual measured values of the diameter of the spot light with respect to the distance to the object when the above-described embodiment is used. Note that the brightness of the environment was 3000 lux.

What should be noted from this data is that the spot diameter does not increase in proportion to the increase in distance, and that the spot diameter hardly changes within the range of 70 m or less, which is the most frequently used range. Furthermore, the spot diameter according to the present invention is approximately 1/3 compared to that of a conventional aberration correction lens, and is extremely sharp.

Further, according to the present invention, since it is composed of only two single lenses, reflection loss on the lens surface is extremely small, and a bright spot light can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the configuration of the present invention, and FIG. 2 is a diagram showing the vertical value configuration of the embodiment of the present invention. 1.2.3.4... Lens surface number 5... Laser light emitter

Claims (1)

[Claims] In a device that projects a spot light far away (10 m to 100 m) by diffusing a He-Ne laser beam with a wavelength of 6328 angstroms using a concave lens and condensing it using a convex lens, ±10% of the following numerical value. Optical systems for laser beams in the range of . Note R_1=110 D_1=2.0 N_1=1.0
R_2=∽ D_2=189.5 N_2=1.5
1516R_3=∽ D_3=2.0 N_1
=1.0R_4=12N_2
=1.51516 However, R: radius of curvature of each surface D: distance N from the surface to the next surface: refractive index of the substance in front of the surface The subscripts are attached to the lens surfaces in order from the front.