JPS62231904A - Optical transmission hose - Google Patents

Abstract

PURPOSE:To improve the transmission efficiency of light and to enable optical large-capacity and intermediate-distance transmission by setting the surface roughness (Ra representation) of the internal wall surface of a hose below a specific value. CONSTITUTION:The surface roughness (Ra representation) of the internal wall surface 2 of the hose 1 is set to <=0.030mu. The material of a sealed hose body 1 wherein an optical transmission medium 5 is held has a refractive index n2 to the wavelength of transmitted light preferably smaller than the refractive index n1 of the material. This condition need not be satisfied to the overall thickness of the sealed hose 1 and the properties of the internal wall 2 coming into contact with the optical transmission medium 5 are specially important factors. Plastics and elastomer are usable as the material of the sealed hose 1, but thermoplastic resin and elastomer which are flexible and can be molded in a tube shape are specially preferable.

Description

[Detailed Description of the Invention] (Industrial Application Field) A system that transmits light by utilizing total reflection at the interface between two types of materials with different refractive indexes is used for optical communication purposes, image guides in endoscopes, etc. It is widely used in the industrial and medical fields as a light guide for various wavelengths of light such as ultraviolet, visible, and infrared light.

Looking at these characteristics from the perspective of the original transmission form, optical communication applications are classified as long-distance transmission of weak capacity light, and image guides and light guides are classified as short-distance transmission of small to medium capacity light.

Recently, optical transmission methods different from these conventional types have been developed.
This is becoming necessary in the concept of marine ranches aimed at enriching the ocean, and the concept of ex-utilization systems for housing such as condominiums aimed at making the living environment in the city more comfortable.

The transmission distance required here is a medium distance of 30 m to 100 m, and the required transmission source capacity is extremely large.

From this point of view, this type of optical transmission system is called a large-capacity optical medium-distance transmission system, and is of a completely different type from conventional optical transmission systems.

The specific requirements that this large-capacity optical medium-distance transmission method must meet are that it is economically possible to transmit large-capacity light, that it is dust-free, and that the attenuation rate of light at 30 m is 1/1/2 of the incident light.
It can be summarized in two points: 1 to 1150.

(Problems to be Solved by the Present Invention) As conventional optical transmission systems, quartz fiber systems, optical glass systems, glass fiber systems, and liquid systems are known, but from this point of view, unfortunately, they are not satisfactory. The system has not yet been discovered.

That is, although the quartz fiber system has excellent properties, its flexibility is limited, and in order to increase the diameter for large-capacity transmission of precious light, it is necessary to bundle a large number of fibers with a diameter of about 10 to 200^. Furthermore, no matter how densely the fibers are bundled, voids remain between the fibers, resulting in poor efficiency. In addition, quartz fibers are relatively expensive and have a high specific gravity, so there is a disadvantage in terms of cost.

In addition, in terms of characteristics, the quartz fiber system has excellent properties in the long wavelength infrared region (2
, 5μ or more), it shows a high loss of 10'dB/km or more, and its value as an optical transmission medium is low in this wavelength range. In addition, plastic fibers are more flexible and cheaper than quartz fibers, and are used in short-distance communications, displays, fiberscopes, etc.
On the other hand, its heat resistance and original transmission efficiency are significantly inferior to quartz-based materials. In addition, it is no different from quartz fiber systems in that it is necessary to bundle a large number of fibers when increasing the diameter.

Optical glass systems have the advantage of being inexpensive light guides, but they have large transmission losses, so they are not limited to short-distance transmission applications, and require a large number of fibers to be bundled in order to increase the diameter. This type has exactly the same drawbacks as the former two types.

A liquid system is a system in which a hollow tube is filled with liquid, and it is easy to increase the diameter. Taking advantage of this feature, it is used as a guide for ultraviolet light to cure ultraviolet curing resin. However, conventional methods have a large original transmission loss, and their use is currently limited to short-distance transmission.

(Means for solving the problem of interlacing points) From the above point of view, the inventors of the present invention, as a result of intensive research, have developed an optical transmission medium that is liquid at room temperature, and a hose made of a flexible material for enclosing the medium. In an optical transmission body composed of
It was discovered that the roughness of the inner wall surface of the hose has a large effect on the original transmission efficiency, and the present invention was completed. That is, the present invention uses a substance that is liquid at room temperature as an optical transmission medium, and the medium and
An optical transmission body composed of a flexible material and a hose for enclosing the optical transmission body, characterized in that the inner wall surface of the hose has a surface roughness (expressed as Ra) of 0.030μ or less. It is related to.

The following tests were conducted on the optical transmission hose according to the present invention. Figure 1
1 is the enclosed hose body, 2 is the inner wall of the enclosed hose,
3 is the outer wall of the sealed hose, 4 is the protective coating layer, 5 is the optical transmission medium, 6 is the end sealing plug, 7 is the inner wall of the end sealing plug, 8 is the outer wall of the end sealing plug, 9 is the base cap. be.

The material of the enclosed hose body l holding the optical transmission medium 5 has a refractive index n2 with respect to the wavelength of the transmitted light equal to the refraction of the medium '4n1
Smaller is desirable. However, this is not necessarily necessary throughout the entire thickness of the enclosed hose 1, and the nature of the inner wall 2 in contact with the optical transmission medium 5 acts as a particularly important factor.

The material for the enclosed hose 1 may be plastics or nystomers, but thermoplastic resins or elastomers are particularly preferred because they are flexible and can be molded into a tube shape.

Specific examples include I-lyethylene, polypropylene,
I-lyester, polyamide, silicone rubber, natural rubber,
Synthetic polyisoprene rubber, polyptazoene rubber, styrene-getadiene copolymer, EPDM, 7" chillam, halonized butyl copolymer, chloroprene rubber, acrylonitrile-butadiene copolymer, halodanated polyethylene, ?-reacrylonitrile , acrylonitrile-methyl methacrylate copolymer, polystyrene, acrylonitrile styrene copolymer, ABS, styrene-methyl methacrylate copolymer, polymethyl methacrylate, cellulose acetate, I realylate, I licargenate, I
polyvinyl chloride, polyvinylidene chloride, polyvinyl acetate ionomer, ethylene-ethyl acrylate copolymer,
Polymethylintene, polyfluoroinglovyl methacrylate, polydimethylsiloxane, polyvinyl acetate,
? Ritetrafluoroethylene, polyacetal, polyvinyl fluoride 1,1+7 vinylidene fluoride, polytrifluoroethylene, polyfluorotrifumyloethylene, tetrafluoroethylene-hexafluoropropylene copolymer, tetrafluoroethylene-perfluoroalkoxyshetylene Examples include copolymers, tetrafluoroethylene-ethylene copolymers, vinylidene fluoride-hexafluoropropylene copolymers, and the like. Among these, materials with low refractive index are particularly preferred.
In this respect, polymers with high fluorine content and silicone polymers are particularly excellent. These polymers can be used alone or as a blend. Also used are those in which only the surface in contact with the transmission medium is treated. In addition, if the flexibility of the transmitter is not important depending on the application, glass, quartz,
It is also possible to use ceramic pipes such as alumina, magnesia, and titania, and metal pipes such as aluminum, stainless steel, and copper, which have been treated to meet the roughness requirements on the inner surface that comes into contact with the transmission medium.

The inventors have made an important discovery regarding the inner wall 2 of the pipe containing the transmission medium, which is one of the key points of the present invention.

In other words, by making the surface roughness of the wall F/' (Ra) measured with a stylus surface roughness meter less than 0.OHμ, it is possible to achieve the desired medium-distance transmission. I found it.

The Ra value here is a widely used method of expressing surface roughness, and is the geometric average of the deviation values of a waveform profile measured from the center line of the waveform. We TATLO this measurement
The measurement was carried out using a stylus type surface roughness meter manufactured by R-HOBSON.

Next is the coating t? 14 is not necessary depending on the application, but is provided for the purpose of protecting the hose from external damage, high temperature and high humidity, and preventing kinks caused by bending the hose. Examples include metal/plastic bellows tubes, helical springs, carbon fibers, organic and inorganic fiber fabrics, spirally wound materials such as rayon, nylon, vinylon, polyester, asbestos, glass, etc., reinforcing layered rubber, plastics, etc. Measures will be taken.

Although not shown in FIG. 1, the inner tube material may be a double tube or multiple tubes, and this may be used alone or in combination with the above-mentioned coating layer.

Glasstics and elastomers are generally used as the material for the outer tube portion of the double tube.

Next, the optical transmission medium 5 will be explained.

In a transmission medium that is homogeneous and contains as few impurities as possible, each medium has its own unique easily transmittable wavelength region with respect to the original wavelength. That is, depending on the type of medium, some have a narrow wavelength range and others have a wide wavelength range. It is necessary to decide which type of transmission medium to use depending on the purpose of use.

The optical transmission medium used in the present invention may be a liquid (1 to 10 centipoise) at the operating temperature. Specific examples include aqueous solutions of inorganic salts, polyhydric alcohols such as ethylene glycol and glycerin, silicone oils such as dimethylsiloxane, hydrocarbons such as polynical, polyester, and fluidized rough-in, halogenated hydrocarbons, and polymers. Examples include polymer solutions diluted with appropriate solvents. In particular, when a wide easily transmittable wavelength range is required, compounds represented by general formulas (1) to (XIV) containing carbon and a halogen element or further oxygen are suitable.

2X2X4 In general formulas (1) to (Vl), X1 to X8 may all be the same or different halogen elements, or some may be other elements or substituents, such as hydrogen, alkyl groups, alkoxy groups, etc. It may be replaced with . Specific examples include nochloromethane, tribromomonofluoromethane, nopromomonofluoromethane, tetrachloro-1,2
-nofluoroethane, 1.1.2-)lichlorotrifluoroethane, 1,1.1-trichlorotrifluoroethane,
1,1.1.2-tetrachloromonofluoroethane, 1
．． 2-fuchloro-1,2-cyfluoroethane, 1-chloro-2,2-difluoroethane, 1,1-dichlorodifluoroethylene, 1,1.2.2-tetrachlorotetrafluorocyclobutane and 1.2.2-trichloro- 3, 3, 4
, 4-tetrafluorocyclobutane, etc.

Also available are tetrafluoroethylene polymers, hexafluoropropylene polymers, and polymers represented by the following general formulas (■) to (XIV).

General formulas (■) to (X■) VC elements, X1 to X, and 4 may all be the same type or A fit halo element, or some may contain other elements or substituents, such as hydrogen, It represents a divalent residue such as an alkyl group substituted with a hydroxyl group, an alkyl group, a phenyl group, an alkoxy group, a CalM xyl group, an ester group, an amide group, etc., a phenyl group, or a polycyclic hydrocarbon group. n,
~ moth represents any positive integer as water qO. Specific examples thereof include 37t-chlorinated ethylene polymer, mefluorinated ethylene dichloride polymer, 1,1 di-difluorinated ethylene polymer, 1,2-difluorinated ethylene polymer, and fluorinated ethylene polymer. Polymer, hexagonalized 7'o
Examples include yH-yano e-fluoroalkyl riether.

Further, it may be a mixture of these polymers or a copolymer of a pace monomer of the above polymers. 19. In the above-mentioned substance group, part or all of the hydrogen may be replaced by deuterium.

We have introduced and defined a measure called optical purity index for these optical transmission media. That is, it is well known that in a low-purity transmission medium containing dirt and dust, these dirt and dust become light scattering points and reduce transmission efficiency. However, it has been found that, despite the apparent transparency of certain types of media, even when using high-precision filtering techniques, the optical transmission loss is extremely large.

In addition, in this type of transmission medium, the output 1
K when mW H/Ha laser light is incident.

It was found that it had scattering points similar to dirt and dust.

On the other hand, it has become clear that in a transmission medium with good transmission efficiency, such scattering points are extremely small.9 As a result of repeated studies based on these findings, we found that the optical purity index is 0.6 or higher. We have found that certain things are particularly desirable as optical transmission media.

Here, the optical purity index is solved, He/N e with an output of 1 mW.
It is expressed as the ratio of the value obtained by subtracting the bright spot area from the light path area to the optical path area when a laser beam is incident on the side of the medium and a bright spot found in the optical path is photographed. For example, when the bright spot area is 0.5 for an optical path area of 1, the optical purity index is 0.5.

In actual measurement, by scanning the laser beam up and down, the optical path area increases, making it possible to measure the force more accurately.

In addition, it is necessary to limit the bright spots to be measured to those that are clear, and to exclude those that are ambiguous. The reason for this is that retro-irradiation light based on reflection from the container wall may generate unclear bright spots.

Next, the end sealing plug 6 will be explained.

Sealing plugs 6 at both ends of the hose are provided to retain the transmission medium. In order to prevent this shape from leaking, various measures are taken, such as designing it to be slightly larger than the inner diameter of the tube, heat-sealing it, and combining it with an O-ring. It goes without saying that the material of this sealing plug has good transparency for the wavelength of the transmitted light, but also that it does not chemically react with the transmission medium that comes into contact with the inner wall 7, and that it does not chemically react with the transmission medium that comes into contact with the outer wall 8. It is necessary to be chemically stable against gases, moisture, etc. in the atmosphere. Specific examples of the sealing material include fused silica, borate glass, flint glass, crown glass, soda glass, chalcognitic glass, fluoride glass, lithium fluoride, sodium fluoride, calcium fluoride, and fluoride glass. Barium chloride, sodium chloride, calcium chloride, potassium chloride, thallium bromide, potassium iodide, KH2-5
, KH2-6° sapphire, ice crystal, magnesia, titania, alumina, silicon, germanium, polystyrene (including high impact), acrylonitrile styrene copolymer, AES, styrene maleic acid copolymer resin, methyl methacrylate styrene copolymer resin, styrene Maleic anhydride resin, methacrylic resin, cellulose acetate,
Polyester Cargonate, Polyester, Polymethylpentene, Polyarylate, yl! ') Ether sulfone, poly:r--f ether ketone, polycargonate, nylon, polysulfone, etc., and depending on the purpose and conditions of use, in addition to the use of single materials, multilayer or Measures such as surface treatment may also be taken.

In addition, the inner and outer walls 7 and 8 may be well polished and may be provided with an anti-reflection film, a protective film, etc., if necessary. The design factors governing the required characteristics of this antireflection film are that its refractive index n is given by n''F, and its film thickness d is given by d=J/4n.

Here, ng is the refractive index of the sealing plug material, and λ is the wavelength of light. Multilayer coatings are particularly preferred for reflecting light containing a wide range of wavelengths. Examples of materials for antireflection coatings include cryolite, magnesium fluoride, thorium fluoride, cerium fluoride, -silicon oxide, zirconia, zinc sulfide, titania, cerium dioxide, dalmanium, and copper telluride. , vacuum evaporation, ion blating, sputtering, etc.

The protective fitting 9 is provided for the purpose of protecting the end of the hose, crimping it, and connecting other equipment and hoses, and is made of metal, plastic, etc., and may be provided with a QIJ song between the hose body or It is also possible to take measures such as providing a thread groove or the like in the material itself.

Further, a lens, filter, etc. can be provided at the end sealing port of this hose if necessary.

(Example) Hereinafter, the present invention will be explained in more detail with reference to Examples.

Example 1 Inner diameter 5φ, outer diameter 6φ, length 3m Surface roughness Ra of inner wall surface
After filling a circular tube of tetrafluoroethylene-hexafluoropropylene copolymer (refractive index nn = 1.338) with = 0.015μ with Flow A rough-in with purity index = 0.95,
A light transmission device was fabricated by sealing both ends of the quartz iron with an outer diameter of 5φ and a length of 30 mm.

Next, an optical transmission body B was produced in the same manner using a tube having the same inner and outer diameters and a length of 9 m.

Figure A2 shows the optical transmission loss (dB) using these optical transmission bodies A and B.
/m), 1 is a white lamp as a white light source, and 2 is a silver interference filter (Toshiba KL40 to KL8Q) to measure specific wavelength component light. I took it out and passed it through 3's optical transmission great man. In the figure, 3-1 is the transmission medium, 3-2 is the enclosure body, and 3-
3 and 3-3' are end sealing plugs. The light that passed through the optical transmission body was measured in dBm using a 4-light/notor meter (22XLA, sensor head 400 manufactured by Quantum Electronics). The same procedure was performed for optical transmission body B as well. If the measured values of the specific wavelength component in the optical transmission bodies A and B are X, , X, then the optical transmission loss at this wavelength is. However, here, l and l are respectively transmitting bodies A.

Indicates the length of B.

The results are shown in FIG. From this result, the wavelength of 550 is
It can be seen that there is an easily transmittable wavelength region near wm.

Example 2 Is the transmission medium flowing A? Trifluoride-chlorinated polyethylene oligomer with a purity index of 0.90 (viscosity 10-30
Centipoise (25℃), refractive index nO== 1.40
) was used, but the transmission loss with respect to wavelength was measured in exactly the same manner as in Example 1. The results are shown in Example 2 in FIG. From this result, this system has a remarkably wide wavelength range of easy transmission <400? It can be seen that light can be transmitted well over the entire visible light range from nm to 8005 m.

Comparative Example 1 Transmission loss with respect to wavelength was measured in exactly the same manner as in Example 1, except that a circular tube with an inner wall surface roughness Ra=0.31μ was used. The results are shown in Comparative Example IK in FIG. From this result and the results of the examples, it can be seen that the surface roughness of the inner wall surface of the transmission hose has a very large effect on the light transmission efficiency.

(Effects of the Invention) The optical transmission body of the present invention enables large-capacity optical and medium-distance transmission, which has been a problem up until now, and can be applied to a wider range of applications and uses by taking advantage of this advantage. The Inno 4 Act is expected to be large.

For example, by attaching it to a loget, etc., and transmitting ultraviolet to infrared light (including laser), it can be used for curing adhesives and resists, patterning cutting, drilling, chemical reactions, etc.
Engraving of the statement (no changes to the contents)
It can be applied. It will also be possible to transmit sunlight into the ocean, basements, buildings, and JL areas, providing lighting and cultivating living things.

Furthermore, concentrated light sources are placed on aircraft, automobiles, railway vehicles, etc.
It can also be used by distributing it to various parts of the optical transmission body.

In addition, as an unusual application field, it is also possible to change the optical transmission capacity by deforming this transmitter by applying external pressure, etc., and it is also possible to change the optical transmission capacity by using this function as a sensor. Be expected.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram of the optical transmission body of the present invention, FIG. 2 shows a method and apparatus for measuring the amount of light, and FIGS. 3 and 4 show the measurement results. 1...Enclosed hose body 2...Inner wall of the enclosed hose 3...Outer wall of the enclosed hose 4...Protective coating layer 5...Light transmission medium 6...Terminal sealing plug 7...Terminal Inner wall 8 of the sealing plug...Outer wall 9 of the end sealing plug...Protective cap Figure 1 1...White light source 2...Silver interference filter 3...Light transmission body 3-1...Transmission Medium 3-2... Enclosure hose 3-3, 3-3''... End sealing plug 4... Optical power meter Figure 2 - Wavelength (mm) - Wavelength (mm) Figure 4 Procedure correction Document (method) % formula % 1. Indication of the case Japanese Patent Application No. 61-72494 2. Name of the invention Optical transmission hose 3. Person making the amendment Relationship to the case Patent applicant address 10 Kyobashi-chome, Chuo-ku, Tokyo No. 1 Within the Patent Department of Brideston Co., Ltd. 5. Date of amendment order: June 4, 1985 (Delivery date: June 24, 1985) 6. Type engraving in the column for a brief explanation of the drawings of the specification to be amended 7. , amend page 21 of the statement of contents of the amendment in a separate document.

Claims (1)

[Claims] In an optical transmission body composed of a substance that is liquid at room temperature as an optical transmission medium and a hose made of a flexible material for enclosing the medium, the surface roughness (Ra) of the inner wall surface of the hose is
An optical transmission hose characterized by having a coefficient (indication) of 0.030μ or less.