JPS587603A - Illuminating device for optical fiber - Google Patents

Abstract

PURPOSE:To irradiate an optical fiber which is coupled at both ends to light sources linearly with constant 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 both ends to light sources 1. Many flaws 4 reaching the core from the surface are formed to the fiber 2, and the density of the flaws 4 is made nonuniform in the extension direction of the fiber 2. Since the photoelectric power injected into the fiber 2 from both ends decreases toward the central part, the density of the flaws 4 is increased toward the central part of the fiber 2 conversely from the attenuating direction of the photoelectric power. When the density of the flaws is defined as (n), the position in the extension direction of the optical fiber as gamma, the length of the optical fiber to be illuminated as 1, and a constant as C, the flaws are formed in the respective positions of the optical fiber at n=1/Ce<-gamma> density from gamma=0 up to gamma1/2, and n=1/Ce<-(1-gamma)> density from gamma=1 2 up to gamma=1.

Description

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

Conventional devices of this type have been 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, and (2) is an optical fiber whose one end is coupled to the light source. (d) Injected into one end (A) without being dispersed from the paste. (3) is light emitted from the other end (B) of the optical fiber.

jl! Figure 2 shows the case of a multi-core optical fiber.A large number of single-core fibers shown in figure 1 are assembled to form a multi-core optical fiber (2).
It consists of

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 emitted from each end of a large number of optical fibers. Since the conventional optical fiber illumination device is configured as described above, it is possible to efficiently irradiate light from the other end (B) of the optical fiber.

Since the light irradiation point is only one point at the B end, there is a drawback that the irradiation range is narrow.

As a way to eliminate these moxibustion points, it has been considered to leak light from parts other than the ends of the optical fiber, and to irradiate light linearly in the direction of extension of the optical fiber.

This method will be explained below.

In FIG. 3 Ir, two light sources (1) are provided for coupling to both ends of the optical fiber. (2) is an optical fiber, which, as is well known, has a core (not shown) forming the central part,
It is composed of a cladding Mii (not shown) that covers the surface thereof. (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 light emitted from the scratch to the outside.

Note that a large number of the scratches (4) described above are formed on the surface of the optical fiber, but the density of the scratches is made to be constant in the extending direction of the optical fiber.

In this case, the optical power injected from both ends of the optical fiber is
It decreases toward the center of the optical fiber in a relationship of approximately x-c·-T with respect to its extension direction. 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, a line of light is formed from the entire optical fiber, but the brightness gradually decreases toward the center of the optical fiber.

This invention attempts to eliminate these drawbacks.
The third point is that many scratches are formed on the cladding layer on the surface of the optical fiber, reaching from the surface to the optical fiber core IC.
Although it is similar to the one shown in the figure, it is characterized in that the density of scratches is non-uniform in the extending direction of the optical fiber.

In other words, the optical power injected from both ends of the optical fiber decreases toward the center according to the above formula, so the density of scratches formed on the surface of the optical fiber is reversed to the attenuation tendency of the optical power. It increases toward the center.

In FIG. 13, when the position to the right from the left end of the optical fiber is γ, and the length of the optical fiber to be illuminated is 1, scratches are formed at each position of the optical fiber.

The density distribution of these scratches is illustrated in FIG. 4.

With the above configuration, the decrease in optical power can be compensated for by the increase in the density of 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 make it brighter.

However, the constant C must be set to a value such that the optical power injected from both ends in FIG. 3 completely leaks to the outside before reaching one point on the optical fiber.

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 of sunlight, laser beam, semiconductor light source, light bulb light source using a filament method, etc.
The material of the optical fiber can be either glass fiber or resin fiber, and the structure of the optical fiber can be either a step-in-six type or a graded index type.

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

This invention has the above-mentioned structure, in which scratches extending from the surface to the core are formed in the cladding layer of an optical fiber whose ends are coupled to a light source, and the density of the scratches is adjusted in the direction of extension of the optical fiber. Since 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 μ.

[Brief explanation of the drawing]

1 and 112 are schematic diagrams showing conventional devices;
The figure is a schematic diagram of an optical fiber with scratches formed on its outer case, and FIG. 4 is a diagram showing the relationship between the density and position of scratches, which is a feature of the present invention. In the figure, (1) is a light source, (2) is an optical fiber, (4) is a scratch, and (5) is irradiation light. In the drawings, the same reference numerals indicate the same or corresponding parts. Agent Patent Attorney Shin Kuzuno - Figure 1 v! Figure 13 → Position (n

Claims (1)

[Claims] 1. A flaw is formed in the cladding layer of the optical fiber whose both ends are connected to a light source, reaching from the surface to the optical fiber core, and light is leaked from this flaw in the radial direction of the optical fiber. What is claimed is: 1. An optical fiber illumination device for irradiating optical power to an optical fiber, characterized in that the density of forming the scratches is non-uniform in the extending direction of the optical fiber. 2. The density of the flaw is n, the position in the extension direction of the optical fiber is r,
When the length of the optical fiber to be illuminated is 1 and the constant is C, the density from r-o to r-7 is °-ZJ', and from T-- to T-1 is n awns. 2. The optical fiber illumination device according to claim 1, wherein scratches are formed at each position of the optical fiber at a density of -7).