KR20040024348A - Plastic optical fiber with multi-layer structure of clad and one side layer of clad, POF with various shape and function, the equipment and method manufacturing the above POFs, applied products - Google Patents

Abstract

PURPOSE: A multi-layered clad structure and one plane type plastic optical fiber are provided, which are fabricated with a desired shape and thus are applied in various applications. CONSTITUTION: According to the method for fabricating a plastic optical fiber(POF) of various shapes and functions, a plastic optical fiber of several shapes is formed to have a core part propagating a light and a clad part guiding the light as having the same function as the prior circular plastic optical fiber. The shape of the plastic optical fiber is determined according to the shape of a die using the prior extruder apparatus. The clad part is formed using a co-extrusion method or a coating method.

Description

Multi-layer clad structure, single-sided plastic optical fiber, and plastic optical fiber with various shapes and functions, manufacturing apparatus and method for manufacturing them, and their application `` Plastic optical fiber with multi-layer structure of clad and one side layer of clad , POF with various shape and function, the equipment and method manufacturing the above POFs, applied products}

The present invention describes various plastic optical fiber manufacturing techniques, their respective functions for the optical fibers and the product fields to which they are applied. Various types of plastic optical fibers are used for lighting, advertising and decoration, and optical fibers classified as special plastic optical fibers are used for imaging, image guide, backlight (backlit) and optical sensors. The present invention intends to make various shapes of plastic optical fibers by using an extrusion method or a coating method, and is formed of a core part through which light is transmitted and a cladding part to guide light as in the conventional circular plastic optical fiber. Conventional technology has produced only a circular plastic optical fiber by using an extrusion method or a base material method, but the shape of the optical fiber of the core portion is determined according to the form of the die using the extrusion method, the clad portion is a composite extrusion method By manufacturing a die in the same way as the die form of the core and wrapping the core portion, various types of optical fibers can be produced.

The present invention seeks to manufacture various types of functional plastic optical fibers, and various shapes of optical fibers are provided with a core die (frame) having a desired shape at the end of an extrusion device, and by installing the clad die on the core die shell according to the die shape, The core and clad of the plastic optical fiber are formed to give the plastic optical fiber of the desired shape. Various types of plastic optical fibers from the die can be quenched by high temperature plastic optical fibers from the die by installing a quenching device to maintain their shape, thereby obtaining a plastic optical fiber of a desired shape. Plastic optical fibers in various shapes can then be coated to the desired thickness to protect the interior shape and obtain a more perfect plastic optical fiber. Existing plastic optical fiber structure consists of only two layers of core and clad, but it is broken by strong tensile force when weaving or aligning fabric with small diameter optical fiber. Although the thickness is inevitably limited, the cladding layer is composed of a multilayer and the Teflon-based material having high tensile strength is used as the final protective film, thereby increasing the resolution of light and manufacturing a plastic optical fiber having strong tensile strength. Therefore, when a panel for imaging is made of a plastic optical fiber having a smaller diameter than a conventional plastic optical fiber, it is possible to provide clearer picture quality. Plastic optical fiber for backlight (backlit) is easy to align optical fiber by using rectangular plastic optical fiber, less light loss because there is no cladding layer on one side, and stripping the cladding layer of light emitting part after optical fiber alignment Since this is not necessary, it is much more advantageous for yield improvement. Hexagonal plastic optical fibers are used for Photonic Crystal Fibers, which can reliably prevent mode dispersion when used as a single-mode tube. The plastic optical fiber used for the optical sensor has a core, no cladding layer, and a convex surface was formed on the core layer to increase the contact surface with the photocatalyst. In another type of light scattering plastic optical fiber, a light diffusing agent may be coated to scatter light between the core layer and the cladding layer, or the light scattering plastic fiber may be produced by causing a clouding phenomenon during the cladding process.

1 is a cross-sectional view of various types of plastic optical fiber formed by a composite extrusion method and a coating method

Figure 2 shows various types of core dies: cross-sectional view of a basic mold for producing the shape of the core portion of the plastic optical fiber in a desired shape.

3 is a simple composite extrusion apparatus and an optical fiber flowchart: a basic apparatus and a simple process flowchart for manufacturing a plastic optical fiber by a composite extrusion method; Raw material supply part-> Die part-> Chiller-> Secondary drawing device-> Coating device-> UV Curing device-> Winding device

4-1 is a hexagonal die front view: a cross-sectional view of a manufacturing frame for manufacturing a hexagonal plastic optical fiber among various shapes of plastic optical fibers, in which a core die and a clad die surrounding the core die are shown.

4-2 is a cross-sectional view of a hexagonal plastic optical fiber consisting of a core layer through which light passes, a cladding layer for guiding light, and a protective layer protecting the cladding layer.

Fig. 5-1 shows a circular special plastic optical fiber (cross section): a plastic optical fiber for imaging and a plastic optical fiber for image guide or a plastic optical fiber requiring strong tensile force, with a core layer, a primary cladding layer, a secondary cladding layer and a final protective film layer. Configuration

5-2 is a path through which light is transmitted to a circular special plastic optical fiber: an image in which incident light is refracted instead of reflected in the core layer, reflected from the secondary clad layer and guided back to the core layer

6-1 is a plastic optical fiber having a different clad structure (cross section): a cladless structure on one side, which is mainly used as a plastic optical fiber for backlight (back light emission).

6-2 shows another type of cladding plastic optical fiber (cross section): a plastic optical fiber with a cladding layer on the back side only, the cladding layer is coated with a light diffusing agent and the back side is coated with a reflecting film.

FIG. 6-3 is a three-dimensional view of a backlight by arranging the plastic optical fibers of FIG. 6-2: Used as a back light emitting device because the incident light passes through the core and the light exits evenly to the part without the cladding

6-4 is a cross-sectional view (sectional view) of fabricating another type of plastic optical fiber by aligning the backlight: when the optical fiber alignment plate is used as a reflective film without coating the reflective film on the optical fiber

6-5 is a die form (front view) for producing a plastic optical fiber shaped like FIG. 6-1.

7-1 is a cross-sectional view of a plastic optical fiber for light metering (left: circular, right: oval): the core has a circular or oval shape, and a plastic optical fiber partially formed with a cladding layer

Figure 7-2 is a three-dimensional view of the optical fiber optical metering light: the incident light enters the optical fiber and the light escapes to the part without the clad

7-3 shows a composite extrusion die shape for manufacturing a plastic optical fiber shaped like FIG. 7-1 (front view).

8 is a cross-sectional view of the plastic optical fiber for the sensor (without clad: core only): a plastic optical fiber with only a core is used by coating a photocatalyst on the core

9 shows another type of plastic optical fiber: an optical fiber manufactured by coating a light diffusing agent between a core layer and a cladding layer or causing a cloudiness during a cladding process

Figure 10 is a three-dimensional view of another type of plastic optical fiber: the light is scattered at the core and clad interface as the incident light passes through the core, the light exits the clad.

The present invention is a technique for manufacturing various types of plastic optical fiber, the process proceeds through the apparatus as shown in Figure 3 to make a plastic optical fiber product as shown in FIG.

1 is a plastic optical fiber of various forms, the core portion is an optical waveguide through which light passes, and the clad portion serves to guide light from leaking to the outside due to total reflection.

2 is a die (die) for determining the shape of the core, the terminal device of the extruder. The die can be manufactured in various shapes in the range of 0.5mm to 1000mm. The size of the die determines the thickness of the last optical fiber, and the size of the die is determined by the withdrawal speed of subsequent processes. In addition, depending on the flexibility of the optical fiber may be secured through the secondary stretching in the subsequent process.

3 is a device for manufacturing a desired plastic optical fiber, the clad raw material and the core raw material is introduced through the raw material supply device of (1) and (2), and the respective screw raw materials in the screw portion of (3) to the die do. The clad die of (4) is manufactured in the same shape as the core die shape of (5), and serves to coat the core layer formed first from the core die from the outside. The thickness of the cladding layer varies depending on the characteristics of the plastic optical fiber, but it is necessary to increase the numerical aperture (NA) so that the total light is transmitted to the core (greater than 0.5), but various shapes commonly used Plastic optical fiber can be used in the range of 2% to 30% of the core depending on the thickness of the cladding layer. Therefore, the spacing between the core die and the clad die may be maintained within the range of 2% to 30% of the minimum diameter of the core die. The core die of (5) is as described in FIG. The cooling apparatus of FIG. 3 (6) quenches the plastic optical fiber to maintain the die shape since the plastic optical fiber from the die is hot. The quench system may use water, or use cooling air or cooling gas. When the plastic optical fiber is quenched and the thickness is determined, the subsequent process enters the secondary stretching process according to the characteristics of the plastic optical fiber. Fig. 7 (7) The secondary stretching is higher than the glass transition temperature of the plastic optical fiber in order to improve the flexibility of the optical fiber. The length of the stretching device (2m ~ 8m) and the temperature (100 ℃ ~ 200 ℃) should be matched well so that it can be stretched to the inside of the plastic optical fiber by applying heat to the temperature. If flexibility issues are not taken into consideration, the device is not necessary and can be transferred directly to the coating process after quenching. (8) Coating device of Figure 3, after the material selection, the pressure difference between the pressure applied to the device and the plastic optical fiber according to the material viscosity is different, first, it is necessary to determine the viscosity of the coating material. Since the coating material here is used as the final protective film, unlike the material of the cladding layer, a heat resistant and impact resistant Teflon-based material is used. 3 (9) is a step of curing the material coated with a heat treatment and UV curing device once as a heat, and the second step to adjust the refractive index of the material by using ultraviolet rays and to completely harden the material.

4-1 illustrates a front view of a hexagonal die, where the core die and the clad die meet.

Figure 4-2 is a cross-sectional view of a hexagonal plastic optical fiber as an example, the material used as the core is the highest refractive index material using PMMA (Poly MethylMethacylate) as a base material, other materials PS (Poly Styrene) I use a PC (Poly Carbonate). For the clad material, when PMMA is used as the core material, a fluoropolymer having a lower refractive index is used. When the PS is used as the core material, the PMMA material is used as the clad material. And when using PC as core material, polyolefin is used as clad. The reason why the materials are paired with each other is because the refractive index of the clad material must be lower than the refractive index of the core material in order for the light transmitted through the core to totally reflect in the clad layer, and the larger the difference in the refractive index, the numerical aperture (NA). Because of this increase, a large amount of light can be received, so the larger the refractive index between the two layers, the better. However, since the draw ratio between the core material and the clad material should be similar and the contact force between the materials should be good, it is preferable to make a pair as described above. The thickness of the clad material makes plastic optical fibers suitable for the application within the range of 2% to 30% of the minimum thickness of the core. The final protective film blocks external moisture and physical forces and increases strength, which increases shear stress, a disadvantage of plastic optical fibers.

The material used is Teflon-based material and PC (Poly Carbonate), and its thickness is used within 50 ~ 500 ㎛ depending on the product use. UV curing method after solvent coating (Coating) is the best method to form the final protective film, another method may be coated by clad extrusion method.

Hexagonal plastic optical fibers are useful for making special tubes for photonic crystal fibers (PCFs). Hexagonal plastic fiber bundles can be made into hexagonal tubes to create more efficient single-mode plastic tubes. .

5-1 is a circular-shaped special plastic optical fiber, which is used to weave fabrics using plastic optical fibers or require strong tensile force, first coating a first cladding layer on a core, and the first coating has a numerical aperture ( In order to increase the Numerical Aperture, it is preferable to use a material having a large difference in refractive index from the core. The core layer uses PMMA, which has good optical properties, and the primary clad layer is a fluoropolymer-based material (refractive index: 1.41 to 1.46). The thickness ratio is controlled within the range of 2% to 20% of the core thickness. Use a lower refractive index THV (Tetrafluoroethylene Hexafluoropropylene Vinylidenefluoride) material (refractive index: 1.366) or a lower refractive index material. The reason for the primary / secondary coating is to reduce the loss of light transmitted to the core by inducing total reflection in the secondary coated clad layer as the light passes through the core.

5-2 shows that while incident light passes through the core, some of the primary clad material is reflected and passes through the core, while some are refracted and directed toward the secondary clad layer. The light directed toward the secondary cladding layer causes total reflection when it meets the secondary cladding layer, returning to the primary cladding layer, and showing the path of refracting back into the core layer. This is to improve shear stress, which is a disadvantage of plastic optical fiber by increasing strength, and when used for weaving fabrics or requiring high tension, the thickness of the final protective film is within the range of 10% to 50% of the core thickness. Should be coated. The material of the final protective film is Teflon series. Plastic optical fibers to be used for large plastic optical screens or images should have a low light loss, a large numerical aperture, and a good optical resolution, so it is desirable to minimize the diameter of the plastic fibers manufactured in the form of a circle. In addition, when the cladding layer is gradually reduced in refractive index from the second to the third to seventh (hill-shaped plastic optical fiber), and a thin coating can reduce the dispersion between modes, thereby improving the optical resolution. Therefore, when the plastic optical fiber is used for imaging, the core diameter is adjusted to 150 μm or less, and the cladding and the final protective film are formed in the same manner as described above, so that the screen is easily manufactured and there is no manufacturing defect.

6-1 is a cross-sectional view of a plastic optical fiber having a different clad structure, one side of which is a plastic optical fiber without a clad and a final protective film. This type of plastic optical fiber uses a extrusion device to produce a core in the shape of a desired plastic optical fiber in the form of a die, as shown in Fig. 6-5, and the clad layer is formed on one side according to the above-described material or thickness. Dies are made so that only the surface can be coated. If only one side of the coating is used for the backlight (back light emission), there is no need to remove the cladding layer in the subsequent process, and the plastic fiber of the square shape rather than the circular is easy to manufacture the backlight and the light is distributed evenly. The light efficiency is good. In addition, instead of the conventional clad material, the cladding layer is coated with a light diffusing agent, and a metal thin film (aluminum, silver, etc.), which has a good light reflectivity, is further coated on the final protective layer to further simplify the backlight process. This becomes very simple. Since the coating of the metal thin film is a high temperature process, if the process is difficult, the reflector is made of a metal thin film sheet without the thin film coating on the plastic optical fiber as shown in FIG. 6-2. Aligning the plastic optical fiber so as to contact the metal sheet to form a backlight sheet (Figs. 6-3 and 6-4).

The backlight sheet is advantageous in the form of a square plastic optical fiber, but may be an elliptical plastic optical fiber as shown in FIG. 6-1.

7-1 is a plastic optical fiber in which a clad layer is partially formed on a circular core layer or an elliptical core layer. This optical fiber can be used for the use of side light because light is constantly passed to the clad-free area as the light passes through the core (FIG. 7-2). The thickness of the cladding layer need not be larger than the core. The distance between the clads also does not need to be constant, and if the cross section of the clad covering the core is in the range of at least 30% to 70%, there is no problem with the plastic optical fiber using metering. Again, in order to satisfy the plastic optical fiber condition, the core layer material should have a higher refractive index than the clad layer material. The final protective film protects the curved cladding layer and the bare core layer from the outside, and the protective layer in contact with the core should be designed to allow light to escape well. Therefore, the refractive index of the material used as the final protective film should be greater than or equal to the core refractive index. When using the core material as a PMMA, the material used as a protective film should be coated with PC (Poly Carbonate) or PS (Poly Styrene) as a protective film, or other materials with light transparency, high strength, and refractive index larger than PMMA should be used. . The core layer can be made not only round but also elliptical, and in other core forms, the clad layer can be partially coated and used for the same purpose.

FIG. 7-3 shows a die shape of a co-extruder for manufacturing the plastic optical fiber of FIG. 7-1. The manufacturing method is the same as that described above.

8 shows a cross-sectional view of a plastic optical fiber used as an optical sensor using a photocatalyst. When the photocatalyst is coated on a plastic optical fiber having only a core, a sunflower-type plastic optical fiber is preferable, which is intended to increase the efficiency of the optical sensor by increasing the contact surface between the photocatalyst and the core layer. do. The convex surface adhering to the core is made of a material having a similar refractive index to the core, such as a method of forming a clad by a complex extrusion method, and a material easily contacting with a photocatalyst should be selected. In this way, the cruciform plastic optical fiber as shown in Figs. 8-4 can also be used as a POF for the optical sensor. The convex surface is formed in the same way as the convex surface of the sunflower type in order to increase the contact surface of the photocatalyst on the square plastic core optical fiber. You can do it.

FIG. 9 is a plastic optical fiber made by coating a light diffusing agent between a core and a clad with another type of plastic optical fiber (light scattering plastic optical fiber) or by intentionally generating a cloudy phenomenon during the clad process. When the core material is PMMA and the clad material is 3FMA or vinyl containing fluorine (chemical symbol: F), turbidity occurs at the core and clad interface.

As described above, when a light diffusing agent is coated or a clouding phenomenon occurs between the core and the clad, when light is transmitted through the core, a large amount of light is scattered and the light evenly penetrates through the cladding layer. By using this phenomenon, it can be used evenly for the device which uses metering, decoration, and backlight. The shape of the optical fiber can be used for backlights such as round and square shapes, and the other shapes can be used for decorative purposes and various purposes. The backlight device is manufactured by arranging such light scattering plastic optical fibers in a reflecting plate.

Plastic optical fiber of various forms according to the present invention is not only useful for optical lighting, sign mall, decoration, but also in various forms of plastic optical fiber for image guide, plastic fiber for backlight (back emitting), optical fiber for optical sensor, etc. By manufacturing, you can produce very useful products throughout the industry. Products that can use these various plastic optical fibers for their applications can be applied to countless applications such as video screens, image transmitters, backlit billboards and backlit applications, and laptops. It is expected to have an impact.

Claims (18)

Besides circular plastic optical fiber, various shapes of plastic optical fiber as shown in Fig. 1 and another type of plastic optical fiber Apparatus for manufacturing various types of dies and applying them to plastic optical fibers by the same method as FIG. Plastic optical fiber in the form of the final protective coating on the various types of plastic optical fiber, such as Figure 1 except for the circular Plastic optical fiber manufacturing apparatus having a structure as shown in Figure 3 for manufacturing various plastic optical fibers, such as When manufacturing a tube from a hexagonal plastic bundle using a hexagonal plastic optical fiber as shown in Figure 4-2 and a special tube for photonic crystal fiber (PCF) In the structure shown in FIG. 5-1, the cladding layer is formed of a multi-layered multilayer structure, and the refractive index of the cladding layer is formed to have a structure in which the refractive index is lowered toward the outside. In the structure shown in FIG. 5-1, the cladding layer and the protective layer are thicker than the core, and the plastic optical fiber using the Teflon-based material as the final protective film and the plastic fiber for imaging using the structure and the product using the same As shown in Fig. 6-1, only one surface is coated with a clad coated plastic optical fiber and a structure using such a structure, and a product using the backlight and a product using the same Plastic optical fiber coated with a light diffusing agent instead of a cladding layer and a product used as a backlight (back light emission) using the plastic optical fiber structure as shown in Figure 6-2, and a product using the same as a light reflecting film as a final protective film 6-3 is a single-layer sheet-type plastic optical fiber that is not a backlight structure made by aligning a backlight structure (back light emitting) using a plastic optical fiber structure as shown in FIG. 6-1 and various square plastic optical fibers. Backlight products and products using the same As shown in Fig. 6-4, a plastic optical fiber coated with only one side with a light diffusing agent instead of a cladding, a backlight product made by aligning it with a reflector, and a product using the plastic optical fiber As shown in FIG. 7-1, the core is partially exposed, and the final protective film is coated with a material having the same refractive index as the core or greater than the refractive index of the core, and a product using side light (photometric) using the same. As shown in FIG. 7-1, the core is partially exposed, and the final protective layer is a plastic optical fiber structure coated with a material having the same refractive index as the core or greater than the refractive index of the core, but not a circular or elliptical rectangular or other plastic optical fiber As shown in (1) to (5) of FIG. 8, a plastic optical fiber having only a core without a clad and partially coated around the core as shown in FIG. 7-1, but the material of the region is the same material as the core or has a similar refractive index. Plastic optical fiber coated with material and used for optical sensors Products used for backlighting (back light emission) with plastic fiber without clad as shown in (1) to (5) of FIG. Products used for decoration or advertising sign with plastic fiber of various shapes as shown in Figure 1 and another type of plastic optical fiber As shown in FIG. 9, a light scattering plastic optical fiber coated with a light diffusing agent between the core and the cladding layer or causing a clouding phenomenon, a backlight device using the same, and a product using the same Plastic optical fiber manufactured to intentionally cause light scattering in the plastic optical fiber