JPH0351804A - Flank light emission optical fiber and its manufacture - Google Patents

Abstract

PURPOSE:To facilitate the manufacture by forming an optical transmission part which transmits almost all of light in a transmission direction and a light dispersion light emission part which scatters light in directions different from the optical transmission direction. CONSTITUTION:An optical transmission medium is formed in a fiber shape and then refractive index variation or the formation of an air bubble is caused by a heat treatment to form the optical diversive light emission part 2 which scatters light directions nearly different from the optical transmission direction. Here, when light is sent from the base side of the optical transmission part 1 of the optical fiber, the light is emitted at the light diversive light emission part 2 to the surface a surface nearly perpendicular to the transmission direction of the optical fiber. Consequently, the manufacture is facilitated and reduced in cost and the optical fiber which is rich in deflection is obtained.

Description

[Detailed description of the invention]

[Industrial Application Field 1] The present invention provides a new display function to an optical fiber for the purpose of optical transmission, and can be used for advertising media (for example, as a substitute for neon tubes), interior decorations, and other various light-using display devices. The present invention relates to a side-emitting optical fiber that can be used in a section and a method for manufacturing the same. BACKGROUND OF THE INVENTION Optical fibers are used to transmit information through glass or plastic as a transmission medium to a destination with as little loss as possible along the way. Main uses include optical communications, medical equipment, and even devices where the tips of fiber bundles are individually separated and dispersed to emit light to produce a display effect. In both cases, the performance required of optical fibers was to eliminate optical loss along the way. To achieve this, in order to give the internal medium a total reflection function, a core layer is provided for the core layer to create a multilayer structure, and a difference in refractive index is created between the core layer and the outer layer, so that the light is totally reflected. For those with a simple structure, such as those that have a refractive index and light transmittance suitable for transmission, such as acrylic plastic in the form of a fiber, and those that have a coating layer on the surface. and so on. In any case, the purpose is to send almost all of the light at the beginning end to the end end of optical transmission. [Problems to be Solved by the Invention] The present inventor has developed an alternative to conventional displays using neon lights, a large number of light emitting elements, light bulb groups, etc., in consideration of the fact that they are expensive and difficult to manufacture. They considered materials with display functions that could be obtained, and focused on optical fibers, which have been making remarkable progress in recent years, and set out to provide new materials suitable for displays.

[Means for solving the problem 1] As a result of considering these problems, we have developed an optical transmission section (1) that transmits almost all of the light in the transmission direction, and a light transmission section (1) that scatters the light in a direction different from the optical transmission direction of the fiber. Light dispersion light emitting part (2
) and developed a side-emitting optical fiber. The light dispersing light emitting part (2) referred to here is a broken part of a total reflection layer in the light transmission direction, or a bubble formed in the fiber medium. The former destroyed portion of the total reflection layer means a portion where the refractive index of the medium is changed from the total reflection condition. The latter type of bubble is not necessarily limited to a cavity filled with gas, but also includes one whose interior is in a vacuum state. The production of such side-emitting optical fibers involves forming an optical transmission medium into a fiber shape, and then heat-treating it to change the refractive index or generate bubbles to create a light-dispersing light-emitting section that scatters light in substantially the opposite direction to the light transmission direction. (2). The heat treatment is carried out to the extent that the optical fiber does not change its shape due to melting, i.e., below its melting point, and furthermore, the internal expansion and volatilization of low-boiling substances may cause a change in the refractive index and the generation of bubbles, disrupting the conditions for total reflection. This is done under the conditions that a reflective interface is formed in the transmission path. Methods for this include passing the optical fiber through an oil bath at an appropriate temperature, bringing it into contact with a heating plate, or heating the surface with a burner. Satisfy the above conditions. Further, after forming the optical transmission medium into a fiber shape, the refractive index of the fiber surface is changed by treating the surface with a solvent to form a light dispersion light emitting part (2) that scatters light in a direction substantially different from the light transmission direction. . Thermoplastic resins (such as methacrylic resins) are preferred as optical transmission media formed into fibers that can be easily subjected to such treatments. [Function] The side-emitting optical fiber of the present invention extends from the light source to the light transmission section (1).
) is scattered in a direction different from the transmission direction in the light dispersion light emitting section (2). There, the light is dispersed on the sides of the fiber and emitted. By changing the color and illuminance of the light source, it is possible to provide a display function along the required length of the fiber in the longitudinal direction. Further, in the method for manufacturing a side-emitting optical fiber of the present invention, the heat treatment changes the refractive index of the medium or generates bubbles, thereby destroying the conditions for total reflection of light by the core layer. Similarly, solvent treatment of the fiber surface causes diffused reflection of light. This also destroys the total internal reflection condition. Due to the destruction of these total reflection conditions, light is scattered in a direction different from the optical fiber transmission direction. There, the light is dispersed on the sides of the fiber and emitted.

[Example] The present invention will be explained in detail below. Example 1 Commercially available methacrylic resin optical fiber (Mitsubishi Rayon ■
Made in Japan, 2.5+mφ, details of additives etc. are unknown) 165
It was inserted into an oil bath whose temperature was adjusted to 0.degree. C. so that a length of 50 al was immersed therein, and heat treated for 2 minutes. next. The optical fiber was taken out of the oil bath in a slightly plasticized state and allowed to cool to room temperature. As a result, as shown in Figure 1, by this heat treatment, when light is sent from the base side of the optical transmission section (1) of the optical fiber, the light dispersing light emitting section (2) in the middle almost moves in the transmission direction of the optical fiber. Light was emitted from a surface at right angles. Example 2 An optical fiber similar to that in the previous example was immersed in an oil bath adjusted to 160°C, and after a while (about 4 minutes) bubbles (3) began to form in the fiber (the detailed reason is unknown). When the number of bubbles reached a suitable level, it was taken out from the oil bath. When cooled to room temperature, an optical fiber with trapped air bubbles was obtained. As a result, as shown in Figure 2, when light is sent from the base side of the light transmission part (1) of the optical fiber, the light is dispersed in the light dispersion light emitting part (2) where there are many bubbles in the middle, creating an aesthetic effect. It became very sexual. Example 3 The same optical fiber as in Example 1 was used, and thinner was sprayed onto its surface. This spraying was repeated several times to form a destructive layer of unevenness on the surface of the optical fiber that could not cause total reflection. As a result, a light dispersion light emitting section (2) was formed which scattered light in a direction different from the light transmission direction of the fiber.

【Effect of the invention】

Since the side surface of the optical fiber emits light as described above, the present invention can be used in place of a neon tube or the like. It is easy to manufacture, inexpensive, and has good flexibility, making it useful as a material for various displays.

[Brief explanation of drawings]

1 and 2 are partial perspective views of the side-emitting optical fiber of the present invention. (1) Light transmission part (2) Light dispersion light emitting part (3) More than bubbles

Claims (1)

[Claims] 1. A side surface having a light transmission section (1) that transmits almost all of the light in the transmission direction, and a light dispersion light emitting section (2) that scatters light in a direction different from the light transmission direction of the fiber. Luminous optical fiber. 2. The side-emitting optical fiber according to claim 1, wherein the light-dispersing light-emitting portion (2) is a broken portion of a total reflection layer in the light transmission direction. 3. A side-emitting optical fiber according to claim 1, wherein the light-dispersing light-emitting portion (2) is a bubble formed within a fiber medium. 4. After the optical transmission medium is formed into a fiber shape, the refractive index is changed or bubbles are generated by heat treatment to form a light dispersion light emitting part (2) that scatters light in a direction substantially different from the light transmission direction. A method for manufacturing a side-emitting optical fiber. 5 After the optical transmission medium is formed into a fiber, the refractive index of the fiber surface is changed by solvent treatment to destroy the total reflection layer, and the light dispersion light emitting part (2) scatters light in a direction substantially different from the light transmission direction. A method for manufacturing a side-emitting optical fiber, characterized by forming a side-emitting optical fiber.