JPS587604A - Illuminating device for optical fiber - Google Patents

Abstract

PURPOSE:To irradiate an optical fiber which is coupled at one end to a light source linearly with uniform brightness by forming flaws reaching the core thereof to said fiber and making the density thereof nonuniform. CONSTITUTION:An optical fiber 2 is coupled at one end to a light source 1. Many flaws 4 reaching the core from the surface thereof are formed to the fiber 2, and the density of the flaws 3 is made nonuniform in the extension direction of the fiber 2. Since the photoelectric power injected into the fiber 2 from one end decreases toward the other end, the density of the flaws 4 is increased toward the other end of the fiber 2 conversely from the attenuation tendency of the photoelectric power. More specifically, if the density of the flaw is defined as (n), the position in the extension direction of the optical fiber as gamma, the position for starting illumination of the optical fiber as gammao, and a constant as C, the flaws are formed in the respective positions of the optical fiber at the density expressed by n=1/ce<-(gamma-gammao> .

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to improvements in optical fiber illumination scissors.

This conventional type filter was constructed as shown in FIG. 1 or 2. In other words, Figure 1 shows the case of a single core (
1) is a light source, (2) is an optical fiber whose one end is coupled to the light source, and the light from light source (1) is transmitted through a lens or parabolic reflector (not shown) provided between the light source and the optical fiber. K is injected at one end after straining it to prevent it from dispersing. (3) is the light emitted from the other end of the optical fiber (the town).

FIG. 2 shows a multi-core optical fiber (2) in which a large number of single-core fibers shown in FIG. 1 are collected to form a multi-core optical fiber (2).

A light source (1) is provided corresponding to a multi-core optical fiber,
The point that optical power is injected into the optical fiber via a lens or the like is the same as in the case of FIG. (3) is light irradiated from each end of the multiple light 7 eyepers. Since the conventional optical fiber illumination device is configured as described above, it is possible to efficiently irradiate light from the other end of the optical fiber (Bl), but since the irradiation point of light is only one point at the B end, the irradiation is difficult. The drawback was that the range was narrow.

As one measure to eliminate this drawback, it has been considered to irradiate light linearly in the extending direction of the optical fiber by leaking light from parts other than the ends of the optical fiber.

This method will be explained below.

In FIG. 3, (1) is a light source, (2) is an optical fiber, and as is well known, a core (not shown) forming the central part,
It consists of a cladding layer (not shown) that covers the surface. (4) are scratches formed in the cladding layer of the optical fiber, each of which reaches deep to the core at the center of the optical fiber.

(5) is the light emitted from the scratch to the outside, and (6) is the light emitted from the other end of the optical fiber.

A large number of the scratches (4) described above are formed on the surface of the optical fiber, and the density of the scratches is kept constant in the extending direction of the optical fiber.

In this case, the optical power injected from one end of the optical fiber is
It decreases in the relationship of approximately xx C·-γ in the extending direction of the optical fiber. This is because the optical power passing through the optical fiber leaks to the outside at a constant rate through scratches formed on the surface of the optical fiber.

Therefore, although it is possible to emit light linearly from the entire optical fiber, its brightness gradually decreases in the direction of extension of the optical fiber.

This invention attempts to eliminate these drawbacks.
It is similar to the one shown in Figure 3 in that a large number of scratches are formed on the cladding layer on the surface of the optical fiber, reaching from the surface to the optical fiber core, but the density of scratches is changed in the direction of extension of the optical fiber. It is characterized by being non-uniform.

In other words, the optical power injected from one end of the optical fiber decreases as it approaches the other end according to the above formula, so it increases toward the other end in proportion to the amount of light formed on the surface of the optical fiber. be.

FIG. 4 shows how the flaw density changes over the length L from the irradiation start position 1 [(γ0) of the optical fiber.

With this configuration, the decrease in optical power can be compensated for by the increase in the density of the scratches, so the leakage optical power irradiated through the scratches is almost constant at any position on the optical fiber and is the same over the entire length. It is possible to set the brightness to .

However, the constant C must be determined so that the afterglow (6) from the B end in FIG. 3 becomes zero.

In addition, in the above explanation, the type of light source, the material of the optical fiber,
Although the structure of the optical fiber was not specifically mentioned, the light source may be any one of sunlight, laser beam, semiconductor light source, filament light bulb light source, etc., and the material of the optical fiber may be glass fiber or resin fiber. The structure of the optical fiber may be either a step index type or a graded index type.

Furthermore, the shape of the scratches is not particularly limited, and may be ring-shaped scratches, spiral-shaped scratches, pinhole-shaped scratches, or other suitable shapes.

The present invention is configured as described above, and forms scratches extending from the surface to the core on the cladding layer of an optical fiber whose one end is coupled to a light source, and the density of the scratches is adjusted in the direction of extension of the optical fiber. Because it is non-uniform, the light injected from the light source can be irradiated linearly with constant brightness in the extending direction of the optical fiber.

[Brief explanation of drawings]

Figures 1 and 2 are schematic diagrams showing a conventional device, Figure 3 is a schematic diagram of an optical core ◆ with scratches formed on its surface, and Figure 4 is the relationship between the density and position of scratches, which is a feature of this invention. FIG. In the figure, (1) is the light source, (2) is the optical fiber, and (4) is the scratch. (5) , (81 is the irradiation light. In the figures, the same reference numerals indicate the same or corresponding parts. Agent Patent attorney Makoto Kuzuno - Figure 1

Claims (1)

[Claims] 1. An optical fiber whose one end is connected to a light source! A flaw is formed in the optical fiber core K t from the α surface of the optical fiber core, and when light is leaked from this flaw, optical power is irradiated in the radial direction of the optical fiber. , an optical fiber illumination device characterized in that the density at which the scratches are formed is non-uniform with respect to the direction of extension of the optical fiber. 2. The density of the scratches is n, the position in the direction of extension of the optical fiber is T,
When the illumination start position of the optical fiber is γ・, and the constant is C
The optical fiber illumination device according to claim 1, characterized in that scratches are formed at each position of the optical 7 eyer with a density expressed as "Cm ear.". 3. Length of the optical 7 eyer to be illuminated If S is L, then the meeting T=T
3. The optical fiber illumination device according to claim 2, wherein the constant C is determined so that all the optical power is irradiated in the radial direction through the flaw in the range up to o+L.