JPH09292538A - Light outgoing end part structure for optical fiber - Google Patents

Abstract

PROBLEM TO BE SOLVED: To vary a size of a spot image without revising the sizes of a whole lens system and a transparent columnar rod by arranging an iris diaphragm on a focal position of a convex lens. SOLUTION: The transparent columnar rod 2, the iris diaphragm 4 and the convex lens 3 are arranged successively from a light outgoing end surface of an optical fiber bundle that light outgoing end parts are bundled. The ratio of length L to diameter D of the transparent columnar rod 2 is 1.75 or above, and the iris diaphragm 4 is arranged on the focal position of the convex lens 3. The light outgoing from the light outgoing end surface of the optical fiber bundle and incident into the rod 2 is mixed in the rod 2 to be made a non- oriented property and to become the uniform light. The outgoing light ray size of the light outgoing from the outgoing surface of the rod 2 is stopped down by the diaphragm 4. The light passing through the diaphragm 4 is converged by the convex lens 3, and a spot formed image is obtained. When the spot size is required to be revised, only the opening size of the iris diaphragm 4 is revised.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical fiber light emitting end structure, and more particularly to an optical fiber light emitting end structure capable of utilizing emitted light of an optical fiber as spot light.

[0002]

2. Description of the Related Art A light emitting end structure of an optical fiber capable of bundling a large number of optical fibers and utilizing the emitted light as spot light has been conventionally focused. There is an optical fiber and a convex lens arranged in front of the light emitting end face of the optical fiber (the former) or a transparent cylindrical rod and a convex lens (the latter).

The former one is such that each optical fiber single-core image (speckle) of each optical fiber bundle does not form a spot image.
A plurality of lenses are arranged, and the focal point is slightly shifted to form an optical fiber emitting end structure. However, in order to change the size of the spot image, it is necessary to change the entire lens system, that is, the type, shape, size and arrangement of the lens. Further, spot image formation, which can be used as spot light with good visibility, was obtained only at a position at a constant distance from the lens system, and the range was very narrow.

The latter one solves this drawback, but in order to change the size of the spot light, it was necessary to change the size of the transparent cylindrical rod.

An object of the present invention is to prevent each optical fiber single-core image (spot) of each optical fiber bundle from being formed into a spot image, and also to make the entire lens system such as the type, shape, size and arrangement of the lens and the like. An object of the present invention is to provide a light emitting end structure of an optical fiber capable of changing the size of a spot image without changing the size of a transparent cylindrical rod.

[0006]

SUMMARY OF THE INVENTION The gist of the present invention is to provide a light in which a transparent cylindrical rod, an iris diaphragm, and a convex lens are sequentially arranged from a light emitting end of an optical fiber bundle in which the light emitting end is focused. An optical fiber having a fiber light emitting end structure, in which a ratio of length (L) / diameter (D) of a transparent cylindrical rod is 1.75 or more, and an iris diaphragm is arranged at a focal point of a convex lens. It is in the light emitting end structure.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described below with reference to FIG. As the optical fiber 1, a known organic or inorganic fiber can be used. As the transparent cylindrical rod 2, known organic transparent materials and inorganic transparent materials such as acrylic resin and polycarbonate resin can be used. The length (L) / diameter (D) ratio of the transparent cylindrical rod is preferably 2.0 or more.

The iris diaphragm 4 has an aperture diameter equal to or smaller than the diameter of the transparent cylindrical rod, and the aperture diameter can be continuously changed. The iris diaphragm is preferably arranged at a distance of 1 to 2 mm from the transparent cylindrical rod in order to avoid heat transfer from the transparent cylindrical rod. A known lens can be used as the convex lens 3, and a plurality of lenses can be used together.

The optical fiber light emitting end structure of the present invention operates as follows. The light transmitted through the optical fiber bundle is emitted from the light emitting end face of the optical fiber bundle and is incident on the incident end face of the transparent cylindrical rod. The light emitted from the optical fiber bundle has almost directivity, but the light incident on the transparent cylindrical rod is sufficiently mixed in the transparent cylindrical rod to be non-directional, and becomes uniform light.

The light emitted from the emitting surface of the transparent cylindrical rod is narrowed down by the iris diaphragm. Since the focal point of the convex lens is located on the surface of the iris diaphragm, the light passing through the iris diaphragm is condensed by the convex lens and spot image formation is obtained. In this structure, the light emitted from the optical fiber 1 can be used as spot light (broken line arrow).

If you want to change the spot diameter,
It is only necessary to change the aperture diameter of the iris diaphragm, and it is not necessary to change the lens system or the like of the optical fiber emission end structure.

[0012]

According to the optical fiber light emitting end structure of the present invention, the size of the spot image can be made continuous without changing the diameter of the whole lens system and the transparent cylindrical rod such as the type, shape, size and arrangement of the lens. Can be changed.

[Brief description of drawings]

FIG. 1 is a schematic view showing an example of a light emitting end structure of an optical fiber according to the present invention.

[Explanation of symbols]

 1 optical fiber 2 transparent cylindrical rod 3 lens 4 iris diaphragm

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yojiro Watanabe 2 1-4-1, Ushikawa-dori, Toyohashi-shi, Aichi Sanryo Rayon Co., Ltd. Toyohashi Plant

Claims (1)

[Claims] 1. An optical fiber light emitting end structure in which a transparent cylindrical rod, an iris diaphragm, and a convex lens are sequentially arranged from a light emitting end of an optical fiber bundle in which the light emitting ends are focused, An optical fiber light emitting end structure in which the ratio of length (L) / diameter (D) of the transparent cylindrical rod is 1.75 or more, and an iris diaphragm is arranged at the focal point of the convex lens.