JPS5940274B2 - Optical fiber device for light wave distance meter - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an optical fiber device disposed between an objective lens and a photoelectric element in an optical distance meter.

In a light wave rangefinder, a light emitting device is used to guide light from a light emitting element to an objective lens and emit it through the objective lens, or to guide light incident through the objective lens to a light receiving element after being reflected by a target. It is known to arrange an optical fiber between a photoelectric element, such as an element and a light receiving element, and an objective lens.

This optical fiber is used not only as a light guiding means to guide light along a predetermined path, but also as a phase difference in the emitted light caused by a difference in position on the light emitting surface of the light emitting element, that is, a phase difference to eliminate phase unevenness. It is also known to have a mixed effect. It is also known that a similar effect can be obtained on the light receiving element side. In this case, the phase mixing effect increases as the diameter of the optical fiber increases, but from the perspective of measurement accuracy, the smaller the area of the light source, the better, so the diameter of the optical fiber on the objective lens side cannot be made too large. The present invention provides a light wave rangefinder, which is arranged between an objective lens and a light emitting element to achieve a sufficient phase mixing effect without increasing the area of the light source, and which is arranged between an objective lens and a light receiving element. The purpose of this device is to provide an optical fiber device that can achieve a sufficient phase mixing effect without increasing external light that causes noise. It consists of an optical fiber having a larger diameter than the end on the lens side.

In other words, the optical fiber is divided into a photoelectric element side and an objective lens side, and the ends of the two are butted and glued together, or the optical fiber is tapered so that the diameter gradually decreases from the end on the photoelectric element side toward the objective lens side. Configure into shapes. Hereinafter, one embodiment of the present invention will be described with reference to the drawings. Light from a light emitting element 1 is condensed by a condenser lens 2, enters an optical fiber 3, passes through the optical fiber 3, and enters a light separating prism 6. After being reflected by the reflecting surface 6a, the light is emitted through the objective lens 4, reflected by a target object such as a corner cube 5, enters the objective lens 4 again, is reflected by the reflecting surface 6b of the light separating prism 6, and is emitted from the light receiving element side. The light passes through the optical fiber 7, passes through the lens 8, and enters the light receiving element 9.

The optical fiber 3 at the end of the light emitting element consists of a large diameter part 3a located on the element side and a small diameter part 3b located on the objective lens side, and these ends are butted against each other and bonded with an adhesive 3c. In this example, the optical fiber on the light receiving element side
7 also consists of a large diameter portion 7a located on the element side and a small diameter portion 7b on the objective lens side, which are bonded to each other with an adhesive 7c. This helps prevent internally reflected light that causes noise from entering the optical fiber, reduces differences in light amount due to differences in measurement distance, and noise due to external light, and improves measurement accuracy. FIG. 2 shows another embodiment of the present invention, in which light from a light emitting element 11 passes through a condenser lens 12 and enters an optical fiber 13.

The optical fiber 13 has an end 13a on the element side and an other end 13b.
It has a tapered shape that has a larger diameter and gradually decreases in diameter from the element side toward the objective lens side. According to the present invention, since the diameter of the optical fiber can be made sufficiently large on the side of the light emitting and receiving element, it is possible to enhance the phase mixing effect within the optical fiber, and it is also possible to reduce the diameter on the objective lens side. The area can be reduced and measurement accuracy can be improved.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of a light wave distance meter showing an embodiment of the present invention;
FIG. 2 is a schematic diagram showing another embodiment. 1... Light emitting element, 3... Optical fiber, 3a... Large diameter part, 3b... Small diameter part,
3c...Adhesive, 4...Objective lens.

Claims (1)

[Scope of Claims] 1. An optical fiber device disposed between an objective lens and a photoelectric element of a light wave distance meter, wherein the end on the photoelectric element side is made of an optical fiber having a larger diameter than the end on the objective lens side. An optical fiber device for light wave rangefinders featuring: 2. The optical fiber device for a light wave distance meter according to the above item 1, wherein the photoelectric element is a light emitting element. 3. The optical fiber device for a light wave distance meter according to the above item 1, wherein the photoelectric element is a light receiving element. 4. In any one of Items 1 to 3 above, the optical fiber is divided into an optical fiber with a larger diameter on the photoelectric element side and an optical fiber with a smaller diameter on the objective lens side, and the ends of these two fibers are butted together and bonded with an adhesive. Glued fiber optic device for light wave distance meter. 5. The optical fiber device for a light wave rangefinder according to any one of Items 1 to 3, wherein the optical fiber has a tapered shape whose diameter gradually decreases from the photoelectric element side toward the objective lens side.