JPH02126203A - Linear luminous body and manufacture thereof - Google Patents

Abstract

PURPOSE: To obtain a linear light emitter capable of emitting light from the peripheral surface of an optical fiber at a free length by providing the surface in the longitudinal direction of a core coated with a clad with a light exit surface. CONSTITUTION: The clad type optical fiber is heated to thermally deform the boundary surface of the clad 3 and the core 1 and to form a rugged surface 2. The rugged surface 2 is irregular fine wrinkles extending in an axial direction. The inside and outside surfaces of the clad 3 are not affected at all by heating. Total reflection conditions are lost by the fine wrinkle-like ruggedness, by which the light exit surface is obtd. The light entering from one end of the optical fiber is emitted in the range of the rugged surface 2 and the linear light emitter is formed. The light emitter is freely curvable and bendable around its own circumference to a circular shape and is effectively used as a light source for biorooms, etc. The reaction products of photosynthesis, if adhered thereon, are easily removable.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a linear light emitter, and particularly to a linear light emitter that causes a part of an optical fiber cable used as a light guide to emit light in a linear manner.

[Conventional technology]

Optical fiber is a material in the field that has made great progress in recent years, from communication materials for optical transmission to practical use in various medical endoscopes by utilizing its ability to transmit light. .

Basically, the functions of optical fibers include localizing and dividing light to illuminate only the areas where it is needed, and freely bending straight light to guide it to the desired location. This is so-called optical control. Therefore, their applications are extremely wide, and they are used in a wide range of applications, including industrial and automotive lighting, artificial solar lights for agriculture, sensors, decorations, and new display systems that replace neon signs and electronic bulletin boards.

[Problem to be solved by the invention]

However, since optical fiber transmission involves receiving light at one end of the fiber cable and emitting light from the other end, its use is limited to point light sources. In particular, in biorooms where bacteria are cultivated and plants are grown under artificial sunlight, culture media are often arranged in multiple stages on fixed shelves, but instead of using conventional lighting equipment, a fiber optic system is used. Sometimes, in order to uniformly irradiate each part with the light source, it is necessary to use a large-diameter fiber bundle and distribute the ends of each fiber to each part.

An object of the present invention is to provide a linear light emitter that emits light at a free length from the circumference of an optical fiber used as a light guide, and a method for manufacturing the same.

[Means to solve the problem]

To achieve the above object, one aspect of the present invention provides a linear light emitter, which is a clad type optical fiber having a light emitting surface on the longitudinal surface of the core covered with the clad.

The linear light emitter of the present invention is obtained by heating a clad optical fiber and thermally deforming the interface between the clad and the core covered with the clad. Furthermore, it is obtained by deforming the clad type optical fiber under pressure to form a ridge line along the length direction at the interface between the clad and the core covered by the clad.

[Effect]

Clad-type optical fibers consist of a double structure in which a core of a transparent material with a high refractive index is covered with a cladding (sheath) of a transparent material with a low refractive index, and the light rays are completely reflected at the interface between the two transparent materials. It is transmitted repeatedly within the core. Optical fibers are broadly divided into quartz-based and plastic-based fibers. Plastic-based optical fibers use materials such as polymethyl methacrylate, which has excellent translucency, as the core component, and often use a special fluorine-based resin for the cladding. 1. In optical fibers for communication, there are examples of measures to prevent light inside the core from leaking into the outer cladding by creating a step in the refractive index between the two, or by creating a gradient in the refractive index in the core itself. be.

In the present invention, a light emitting surface is formed on the surface of the core covered with the cladding, and light is actively emitted from within the core through the cladding onto the peripheral surface of the fiber. The formation of a light emitting surface on the core surface is achieved by heating the fiber curves at a temperature near the thermal deformation temperature of the core or by pressing and deforming them. Figure 1 (-) shows an example of the uneven surface 2 formed on the surface of the core 1 by heating the fiber. The uneven surface 2 is irregular fine wrinkles extending in the axial direction as shown in the figure. The fine wrinkle-like unevenness formed by heating the necessary range in the length direction of the optical fiber 4 by an arbitrary method, which is not influenced in any way by the inner and outer surfaces of the optical fiber 3, becomes the light emitting surface, and the fiber Light incident from one end emits light within the range where the uneven surface 2 is formed, and a linear light emitter can be formed in a part of the light guide.

The reason why it becomes possible to emit light from the peripheral surface of the optical fiber by heating it or deforming it under pressure is thought to be because the total reflection conditions set between the core and the cladding are broken. By heating, as shown in FIG. 1 (sulfur), a clearly wrinkled uneven surface 2 is formed on the surface of the core 1, or fine undulations (microbending) 21 are formed in the longitudinal direction, and the first Even if a ridge line is formed on the entire core 1 including the longitudinal direction of the circumferential surface by pressure deformation as shown in FIG. The reflection conditions are broken and light is emitted from the peripheral surface of the optical fiber.

〔Example〕

Examples of the present invention are shown below.

(Example 1) In FIG. 2, the cylindrical heater 5 placed vertically is energized, and the temperature control device i6 connected to the power source of the heater 5 is
Set the temperature to 50@C, measure with thermocouple 7, and turn on heater 5.
The optical fiber strand 4 is passed through the heater 5 while maintaining the temperature at 150°C, and the optical fiber strand 4 is pulled at a speed of about 5 cm per second with tension applied to the optical fiber strand 4. Let it pass.

When the heater 5 was pulled out by about 1 m, the power to the heater 5 was turned off, and the wire 4 was pulled out from inside the heater 5. The obtained optical fiber strand 4 has the first
The uneven surface shown in the figure was formed on the surface of the core, and when light was incident on the optical fiber 4 from one end, the light was emitted almost uniformly from the longitudinal surface of the optical fiber 4.

Next, metal halide lamp HTI400v manufactured by Osram.
The luminous flux of the projector using /24 is focused to a diameter of 40 cm.

Fifty light guide portions of the optical fibers obtained in this example were bundled and their ends were placed within the condensing diameter. When the linear light emitter parts of 50 strands were arranged on a black paper so that they were in contact with each other, and an illuminance meter was applied to this, an average value of 4,000 lux was obtained.

(Example 2) The three optical fiber strands used in Example 1 were arranged in a close-packed hexagonal system, the curves were pressed, and the cross-sectional shape of each strand was heated in the same manner as in Example 1. was transformed into a hexagonal cross section. When the light beam from the projector was inputted from the end of the light guide section of the bundle, light was emitted uniformly over the entire length of the linear light emitter section.

(Example 3) One of the optical fiber strands 4 used in Example 1 was cut into a groove extending over a range of approximately 301 mm from one end thereof and provided in one of the pair of flat jigs 11a and llb shown in FIG. Width 1■, depth 0.8■) 12, insert the strand 4 into both jigs 11a,
It was sandwiched between ttb and pressurized with a vise to deform the cross section into a rectangular shape. When the light beam from the projector was applied to the end face of the light guide portion of the obtained wire 4, the portion deformed under pressure became a linear light emitter and uniformly emitted light.

〔Effect of the invention〕

As described above, according to the present invention, a linear light emitting body can be obtained by simply heating or pressurizing an optical fiber strand, and the obtained light emitting body can be used in a straight shape, curved shape, circular shape, etc. It can be bent into any shape and emitted light.

Further, according to the present invention, since the smoothness of the cladding surface is not impaired, even if photosynthetic reactants adhere to the cladding when used as a light source in a bioroom, it can be easily removed.

[Brief explanation of drawings]

Figure 1 (- to (c) is an enlarged perspective view showing the main part of an optical fiber strand showing an example of the present invention, Figure 2A is a configuration diagram of the manufacturing equipment used in Example 1, and Figure 3 is an example of the implementation. It is a perspective view of the jig used in Example 3. 1... Core 2... Uneven surface 3...
Cladding 4... Optical fiber strand 5...
・Cylindrical heater lla, llb...Jig z1
...Waviness 31...Ridge line <b) (C) Figure 1 Figure 3

Claims (3)

[Claims] (1) In a clad type optical fiber, a linear light emitter characterized by having a light emitting surface on the longitudinal surface of a core covered with a clad. (2) A method for manufacturing a linear light emitter, which comprises heating a clad optical fiber to thermally deform the interface between the clad and a core covered by the clad. (3) A method for producing a linear light emitter, which comprises deforming a clad optical fiber under pressure to form a ridge line along the length at the interface between the clad and a core covered by the clad.