JP2000098166A - Branching type optical transmission device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To embody optimum incidence efficiency in a relation between the exit area of a light source and the total light receiving area of optical transmission tubes with respect to a plurality of the bundled optical transmission tubes such that the spacing between the tubes is not always required to be minimized. SOLUTION: This branching type optical transmission device is formed by bundling a plurality of simple substance of the optical transmission tube each consisting of cylindrical cladding 10 having flexibility and a transparent core 1 which is packed into this cladding 10 and is formed of an elastically deformable solid material having the refractive index higher than the refractive index of the cladding 10 by the bundling member 2. When the exit area of the light source with respect to a plurality of the bundled optical transmission tube is >=65% of the total light receiving area of the optical transmission tubes, the bundling member 2 is diametrally reduced to deform the optical transmission tubes so as not to excessively flatten the tubes, by which the total light receiving area ratio of the optical transmission tubes within the bundling member 2 is regulated to <=95%. When the exit area of the light source with respect to a plurality of the bundled optical transmission tube is <=100% of the total light receiving area of the optical transmission tubes, the bundling member 2 is diametrally reduced to deform the optical transmission tubes so as not to excessively flatten the tubes, by which the total light receiving area ratio of the optical transmission tubes within the bundling member 2 is regulated to >=85%.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a branching type in which a plurality of optical transmission tubes in which a transparent core having a refractive index higher than that of a cladding is filled in a flexible cylindrical cladding are bundled with a binding member. The present invention relates to an optical transmission device.

[0002]

2. Description of the Related Art An optical transmission tube in which a transparent core is filled in a flexible tubular cladding is disclosed in U.S. Pat. No. 3,814,497 and U.S. Pat. The invention described in U.S. Pat. No. 5,332,227 and the invention described in U.S. Pat. No. 5,333,227 are known. The first prior art discloses a waveguide consisting of a large number of rods which are parallel and closely arranged to each other,
One rod constitutes the light transmission tube. This rod has an organic liquid core filled in a main body (cladding). It is disclosed that the liquid core is made of tetrachloroethylene or a mixture thereof with carbon tetrachloride. A second prior art is a flexible hollow tube made of a plastic material, a photoconductive liquid filled in the tube and having a higher refractive index than the plastic material forming the tube; Disclosed is a flexible light guide comprising light transmitting means for closing both ends. The light transmitting means is a window made of quartz or quartz glass, and an aqueous solution of an inorganic salt is used as the photoconductive liquid. Finally, the prior art discloses an optical waveguide in which a hollow tube-shaped cladding having both ends opened is filled with a fluid core having a higher refractive index than the cladding, and sealing plugs are fitted at both ends of the cladding. are doing.

A conventional example of the above-described optical transmission tube is as follows.
In each case, the hollow interior of the cladding is filled with fluid, and both ends of the cladding are sealed with hard light transmissive windows or sealing plugs. When light from a high-power light source is incident on such an optical transmission tube, the window or sealing stopper is made of quartz glass, Pyrex glass, or multi-component glass in order to prevent heat from entering the optical transmission tube and prevent contamination. And the like have been suitably used. By bundling a plurality of such light transmission tubes, binding the light incident ends, sending light from one light source to the plurality of light transmission tubes,
Attempts have been made to branch each light transmission tube.
For example, as shown in FIG. 12, two cores of a fluid are filled in a cylindrical cladding 101 having flexibility, and both ends of the cladding 101 are sealed with sealing plugs 102 made of inorganic glass. The light incident end side of the transmission tube 100 is bundled by the binding member 103, and light from one high-output light source is incident on the bundled end portion so that the two light transmission tubes 10
An attempt was made to send light to zero.

In the conventional example shown in FIG. 12, the sealing plug 102 made of inorganic glass existing at the light incident end is not deformed by an external force, so that a gap 105 is formed in the space bound by the binding member 103. Even if light is incident on this space, light cannot be incident on each light transmission tube 100 at high efficiency. In this conventional example, the filling rate of the light transmission tube 100 in the binding member 103 is about 50%, and the light incidence rate is poor. Therefore, a single optical transmission tube consisting of a flexible cylindrical cladding and a transparent core filled with the cladding and having a higher refractive index than the cladding and formed of an elastically deformable solid material is used. A device in which a plurality of tubes are bound by a binding member and the tubes are deformed by external force so as to minimize the gap between the tubes has been developed.

[0005]

However, the above optical transmission tube can easily minimize the gap in the case of a core material or a clad material which is flexible and has a low elastic modulus, but is hard as in the case of a plastic having a high elastic modulus. When a material is used, the external force (caulking force) applied to the optical transmission tube must be considerably increased to minimize the gap. Then, a stress is applied to the light transmission tube, and the light is flattened and the light is lost due to scattering or the like. In addition, even if crimped to the minimum, it took time to relax the stress, and the efficiency was poor from the viewpoint of manufacturing the optical transmission tube.

Accordingly, the present invention realizes an optimum incidence efficiency in relation to the emission area of the light source and the total light receiving area of the light transmission tubes for a plurality of bundled light transmission tubes, and always minimizes the gap between the tubes. It is an object of the present invention to provide a branch type optical transmission device which does not need to be configured.

[0007]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a flexible tubular cladding and an elastically deformable filler filled in the cladding and having a higher refractive index than the cladding. A light transmitting tube comprising a transparent core formed of a transparent solid material and a plurality of light transmitting tubes each bundled by a binding member, wherein an emission area of a light source with respect to the plurality of bundled light transmission tubes is light. When the total light receiving area of the transmission tube is 65% or more, the diameter of the binding member is reduced to deform the light transmission tube so as not to be excessively flat, and the light receiving area ratio of the light transmission tube in the binding member is set to 95% or less, When the emission area of the light source with respect to the plurality of bundled light transmission tubes is 100% or less of the total light receiving area of the light transmission tubes, the diameter of the bundling member is reduced and the light transmission tubes are excessively flattened. Is obtained the light receiving area ratio of the light transmission tube is 85% or more at odd deforming binding member.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the drawings.

In the embodiment shown in FIG. 1, four light transmission tubes 1 are bound by a binding member 2 at each light incident end 1a side. At the time of binding by the binding member 2, an external pressure is applied to the light transmission tube 1 to deform the light incident end 1 a side of the light transmission tube 1, thereby reducing the gap between the light transmission tubes 1 in the binding member 2. As a result, the light transmission tubes 1 bundled by the binding member 2 are deformed from the state shown in FIG. 3 as shown in FIG. 1, and each tube 1 is deformed so as not to be excessively flat.

The light transmission tube 1 comprises a flexible tubular cladding 10 and a transparent core 11 filled in the cladding 10 and having a higher refractive index than the cladding 10. As a material for forming the cladding 10, it is preferable to use a material having flexibility, such as plastic or elastomer, which can be formed into a tube shape and has a low refractive index. Specific examples thereof include polyethylene, polypropylene, polyamide, polystyrene, ABS resin, polymethyl methacrylate, polycarbonate, polyvinyl chloride, polyvinylidene chloride, polyvinyl acetate, polyethylene-acetic acid copolymer, polyvinyl alcohol, and polyethylene-polyvinyl alcohol. Polymer, fluororesin, silicone resin, natural rubber, polyisoprene rubber, polybutadiene rubber, styrene-butadiene copolymer, butyl rubber, halogenated butyl rubber, chloroprene rubber, allyl rubber, EPDM,
Acrylonitrile-butadiene copolymer, fluoro rubber,
Examples include silicone rubber. Among them, silicone-based polymers and fluorine-based polymers having a low refractive index are particularly preferred. Specifically, silicone-based polymers such as polydimethylsiloxane polymer, polymethylphenylsiloxane polymer, fluorosilicone polymer, polytetrafluoroethylene (PTFE), Ethylene-perfluoroalkoxyethylene copolymer (PFE), polychlorotrifluoroethylene (PCTFE), ethylene tetrafluoride-ethylene copolymer (ETFE), polyvinylidene fluoride, polyvinyl fluoride, vinylidene fluoride-3 Fluorinated ethylene copolymer, vinylidene fluoride
Examples include propylene hexafluoride copolymer, vinylidene fluoride-propylene hexafluoride-ethylene tetrafluoride terpolymer, tetrafluoroethylene propylene rubber, and fluorine-based thermoplastic elastomer. Each of these materials can be used alone or in combination of two or more.

The core 11 is made of a material which is easily deformed and has flexibility which does not cause a decrease in light transmittance due to a distribution of a refractive index due to a difference in elastic modulus of the material even when the material is deformed under pressure. The materials shown are preferred, and specifically, methyl acrylate, other acrylates that can obtain a transparent polymer that can be copolymerized with an alkyl acrylate such as methyl methacrylate, a flexible acrylic polymer obtained by copolymerizing methacrylate, or a silicone gel Also, other gel-like materials and rubber-like materials can be used.

In FIG. 3, reference numeral 3 denotes an emission area of the light source. In this embodiment, the emission area 3 is the light transmission tube 1.
Slightly exceeds 100% of the total light receiving area of Therefore, after deforming the light transmission tube 1 by applying external pressure (FIG. 1),
The light receiving area ratio of the light transmission tube 1 in the binding member 2 was set to 95% or less.

The degree to which the plurality of light transmission tubes 1 are tightened has an optimum value. Tube light receiving area ratio is S (%)
And the light receiving area of all the tubes after tightening is S ₁ ,
Assuming that the inner diameter area of the binding member 2 after tightening is S ₀ , S = S ₁ / S ₀ × 100. Further, the filling rate is C (%) as a shape index of the branching efficiency when tightened, the effective void area (the void inside the light source diameter other than the tube after tightening) is D ₁ , and the light source diameter is If the area is D ₀ , C = 100−D ₁ / D ₀ × 100. The relationship between the filling ratio C and the tube light receiving area ratio S changes depending on what is used for the core 11 and the cladding 10 (mainly a difference due to the elastic modulus). As the tube light receiving area ratio S increases, C also increases, and C reaches 100% at a certain point and does not change. Also,
When the elastic modulus of the core 11 or the cladding 10 is low, the gradient of the graph of the relationship between the filling rate C and the tube light receiving area ratio S increases, and when the elastic modulus is high, the filling rate C does not easily reach 100%. The slope becomes gentler. When considering the light receiving efficiency and transmission efficiency of the branch type optical transmission tube, it is necessary to consider the following two ways. (a) Transmission efficiency Rs per one branching type optical transmission tube (b) Light receiving efficiency Rt Rs as a whole branching type optical transmission tube is so-called how much light is lost by one optical transmission tube, It is determined as the ratio of the transmitted light amount of one light transmission tube that is not completely clamped and one light transmission tube that is clamped and branched. The measuring method is measured by the measuring method shown in FIG. R
s decreases as the tube light receiving area ratio S increases (the optical transmission tube 1 becomes flatter when tightened), and increases when the tube light receiving area ratio S decreases. This is a loss due to the flatness of the light transmission tube 1.

Let us now consider the behavior of C and Rs as a function of S. FIG. 5 shows the experimental values of C and Rs. For the four-branch light transmission tube 1, the ratio W of the light-emitting area of the light source to the total light-receiving area of the four branched light transmission tubes 1 before clamping was changed.

As described above, as the tube light receiving area ratio S of the light transmission tube 1 increases, C increases and Rs decreases. C is greatly affect the branching efficiency of the branched optical transmission tube by diameter D ₀ of the light source. If the diameter of the light source is large, the air gap and the like are not affected, and if the diameter of the light source is small, the effect of the air gap is large.

Rt is the diameter D of a certain light source.₀To
And how much the branch type optical transmission tube is
The ability to transmit a large amount of light depends on the filling rate C due to the gap on the light receiving surface,
This is the amount that is issued including all of the above Rs. this is
As shown in FIG. ₀And C and further depending on Rs
Value. The element given to Rt is D₀When
There are mainly Rs and C. Since Rs and C are functions of S, Rt = Rt (D₀, C, Rs) = Rt (D₀, S) As described above, Rt is D₀, Considered to be a function of S
From experiments, the light source diameter D₀, Tube light receiving area ratio
Rt may be determined by changing S variously.

In the measuring method shown in FIG. 4, light emitted from a light source is incident on an integrating sphere, a hole is made in the other of the integrating sphere, and the diameter is equal to the diameter of the branch type optical transmission tube and one branch type optical transmission tube. A single unbranched light transmission tube is set, and the other light transmission tube is connected to another integrating sphere to measure the light quantity of each one. Since light is uniformly incident from the integrating sphere, the transmission efficiency per line can be measured.

As shown in FIG. 6, the light transmission amount of the branch type light transmission tube is measured by setting the light transmission tube to light sources having various condensing diameters, making light incident thereon, and setting the branch light transmission tube by an integrating sphere. Measure as a combined light quantity. that time,
The center of the light source is matched with the diameter of the tube so that light is evenly incident (see FIG. 7).

FIG. 8 shows the relationship between the tube light receiving area ratio and the light amount when the emission area of the light source with respect to the bundled (before tightening) light transmission tubes 1 is 132% of the total light receiving area of the light transmission tubes 1. Show.

The tube light receiving area ratio (the degree of tightening and the degree of diameter reduction of the binding member 2) when the emission area of the light source with respect to the plurality of bundled light transmission tubes 1 is 24% of the total light receiving area of the light transmission tubes 1. FIG. 9 shows the relationship between the light amounts.

FIG. 10 shows the relationship between the tube light receiving area ratio and the light amount when the total light receiving area is 73%.

In the case of FIG. 8, it is better not to tighten strongly, and in the case of FIG. 9, it is better to tighten tightly.
In the case of 0, the same amount of light transmittance is obtained with or without tightening. Rs and C are contradictory, as you can see, raising one will lower one and lowering one will raise the other. Then, there should be an optimal value in how to take Rs and C. In fact, it is better to increase the light receiving area ratio S when the light source condenses less than 10φ (mm) (the filling rate C becomes dominant). Good (one transmission efficiency Rs becomes dominant). The core 11 used in the experiments of FIGS. 8 to 10 is made of a soft acrylic resin (elasticity 5 × 10 ⁷ dyn).
/ Cm ² ) and the diameter of one optical transmission tube 1 is set to 5.
Four pieces having a diameter of 9 mm (φ5.9) were used. Binding member 2
A metal sleeve was used, and the diameter was reduced by caulking the metal sleeve.

As the binding member 2, a base, a metal sleeve, or the like can be used. The light incident ends 1a of the plurality of optical transmission tubes 1 can be inserted into the base or the like, and the base can be swaged to reduce the diameter after the insertion. it can. Alternatively, a heat-shrinkable tube can be used as the binding member 2. A method of inserting a plurality of light transmission tubes 1 into the heat-shrinkable tube, heating the heat-shrinkable tube, and using the shrinkage force to reduce the diameter. Etc. can be exemplified. Regarding the degree of compressive deformation in this case, for example, if the tightening is weak, the cross-sectional area is not evenly distributed,
Further, a gap that is not filled with the light transmission tube 1 is formed, and the loss of light incidence increases. Conversely, if the tightening is too strong, the core will be broken in severe cases, and the loss of light incidence will increase.

In the present invention, the cladding 10 can be coated with an appropriate coating material for the purpose of protecting the light transmission tube 1, and the coating material may be plastic, elastomer, metal, glass, inorganic material, or the like. Specifically, polyamide, epoxy resin, polyvinyl chloride, polycarbonate, polystyrene, fluorine resin, butyl rubber, halogenated butyl rubber, polyethylene, polypropylene, polyurethane, hydrochloric acid rubber, natural rubber, polyisoprene rubber, polybutadiene rubber, chloroprene The cladding 10 can be coated with a polymer material such as rubber, acrylic rubber, EPDM, or fluororubber by coating, extruding, winding in a tape shape, or performing heat shrinking. Also, SUS, aluminum,
Copper, iron and other metal materials, or the above polymer materials formed into pipe shape, bellows tube, spiral wire shape,
The cladding 10 filled with the core 11 may be inserted. Furthermore, a metal material can be coated on the outer periphery of the cladding 10 by plating, vapor deposition, sputtering, or the like. Such a covering material can be provided not only for protection of the light transmission tube 1 but also for the purpose of shielding light or emitting light only at a required portion. For example, by making a hole in the required part of the coating material or making it transparent,
Light leaks out from the portion, and a large number of spot-shaped or line-shaped light-emitting bodies can be formed.

A plurality of light transmission tubes 1 can be bundled by the binding member 2 and the light incident window member 3 can be joined to the light incident side end surface 1a (see FIG. 11). Examples of the window material 3 include quartz glass, pyrex glass, multi-component glass, BK-7 glass, sapphire, inorganic glass such as quartz, polyethylene, polypropylene, ABS resin, acrylonitrile / styrene copolymer, and styrene / butadiene copolymer. Polymer, acrylonitrile / EPDM / styrene terpolymer, styrene / methyl methacrylate copolymer, (meth) acrylic resin, epoxy resin, polymethylpentene, allyl diglycol carbonate resin, spirane resin, amorphous polyolefin, polycarbonate, polyamide , Polysulfone, polyallylsulfone, polyethersulfone, polyetherimide, polyimide, polyethylene terephthalate, diallyl phthalate, fluorocarbon resin, polyester carbonate, silicone Organic glass or plastic transparent material such as resins. Among them, quartz glass, Pyrex glass, inorganic glass such as multi-component glass is not only transparent, but also excellent in heat resistance, and also chemically stable,
It does not chemically react with the core contacting at its inner end face or the gas or moisture contacting at its outer end face, and provides excellent performance in the long term.

[0026]

As described above, according to the present invention, when the emission area of the light source with respect to the plurality of bundled light transmission tubes is 65% or more of the total light receiving area of the light transmission tubes, the bundling member is connected. The diameter of the light transmission tube is reduced so that the light transmission tube is not excessively flattened so that the light receiving area ratio of the light transmission tube in the binding member is 95% or less, and the emission area of the light source with respect to the plurality of bundled light transmission tubes is light transmission. When the total light receiving area of the tube is 100% or less, the diameter of the binding member is reduced so that the light transmission tube is not excessively flattened, and the light receiving area ratio of the light transmission tube in the binding member is set to 85% or more. As a result, the light transmission efficiency is improved.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a preferred embodiment of the present invention.

FIG. 2 is a sectional view taken along line II-II of FIG.

FIG. 3 is a diagram illustrating a relationship between an emission area of a light source and a light transmission tube before a binding member is tightened.

FIG. 4 is a diagram showing a method for measuring optical transmission efficiency.

FIG. 5 is a graph showing a relationship between a tube light receiving area ratio and a light amount.

FIG. 6 is a diagram showing a method of measuring the amount of light transmission of a branched optical transmission tube.

FIG. 7 is a diagram showing a diameter of a light source with respect to an incident end of a branched optical transmission tube.

FIG. 8 is a graph showing a relationship between a tube light receiving area ratio and a light amount.

FIG. 9 is a graph showing the relationship between the tube light receiving area ratio and the light amount when the emission area of the light source for a plurality of bundled light transmission tubes is 24% of the total light receiving area of the light transmission tubes.

FIG. 10 is a graph showing the relationship between the tube light receiving area ratio and the amount of light when the total light receiving area is 73%.

FIG. 11 is a sectional view showing another embodiment using a window material.

FIG. 12 is a sectional view showing a conventional example.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 light transmission tube 2 binding member 3 emission area of light source 10 cladding 11 core

Claims (1)

[Claims] 1. An optical transmission tube comprising: a flexible tubular cladding; and a transparent core filled in the cladding and formed of an elastically deformable solid having a higher refractive index than the cladding. A plurality of single light-emitting devices bundled together by a binding member, wherein the light-emitting area of the light source with respect to the plurality of light-transmitted tubes is more than 65% of the total light receiving area of the light transmission tubes. By reducing the diameter of the member and deforming the light transmission tube so as not to be excessively flat, the light receiving area ratio of the light transmission tube in the binding member is set to 95% or less, and the emission area of the light source with respect to the plurality of bundled light transmission tubes is reduced. When the total light receiving area of the light transmission tube is 100% or less, the diameter of the binding member is reduced to deform the light transmission tube so as not to be excessively flat, and the light transmission tube in the binding member is reduced. Branched optical transmission apparatus characterized by a light-receiving area ratio was 85% or more.