JPH01187505A - Light diffusing tube and its manufacture - Google Patents

Abstract

PURPOSE:To efficiently change rays of light having a high condensing property or directivity to rays of light having a high spatial distributing property from a tubular light source by filling up the transparent tubular body of the light source, the surface roughness of inner wall surface of which is specified, with a core material having a refractive index higher than that of the tubular body. CONSTITUTION:A light diffusing tube 1 is constituted of a transparent tubular body 2 filled up with a core material 3 and the openings at both ends of the tubular body 2 are respectively closed up with window materials 4 and 5. The refractive index of the core material 3 is higher than that of the material used for constituting the tubular body 2 and, moreover, the inner wall surface of the tubular body 2 is formed in a rough state, with the surface roughness of the inner wall surface being set within the range of 0.01-0.6mum in the mean roughness of center line Ra, so that at least one end of the tubular body 2 can be used as a light collecting section and its peripheral surface can be used as a light diffusing section. Therefore, rays of light having a high condensing property or directivity can be changed efficiently to rays of light having a high spatial distributing property from a tubular light source.

Description

[Detailed Description of the Invention] 111 Natsukasa ■Fumi 1 The present invention relates to a diffuser tube that converts highly condensing light into light with a high spatial distribution. Fields where it is used are marine breeding farms, vegetable factories, and 9 artificial breeding rooms.

In solar power utilization systems such as hospitals and urban condominiums, it is used by connecting to the light output end of light pipes, and in fields where artificial light is sent through optical transmission lines, such as hazardous materials warehouses, mine shafts, It is used in chemical plants, pipelines, underwater lighting, oil lighting, dangerous work access lighting, etc. by connecting to the light output end of a light pipe or directly to a lamp house.

[ ] "The properties required of a dim light or light source vary depending on the purpose of use, such as brightness, wavelength distribution, and homogeneity of the light.

A light source with optimal characteristics is selected, taking into consideration factors such as light-gathering properties (2) heat generation properties, and light source life (9) price.In order to transmit light over long distances, a light source with excellent light-gathering properties is required. In such cases, the light can be propagated through space using optical auxiliary means such as lenses, or propagated through optical transmission lines such as optical fibers, and transmitted to the necessary locations, such as in solar power systems. In recent years, as a means of transmitting sunlight at low cost, sunlight has been focused by a lens and introduced into an optical fiber. However, the light focused by a lens or the light transmitted by an optical fiber has strong focusing and directivity, and the brightness is so high that it is physiologically uncomfortable, and the space in which the light can be used is also narrowed. It becomes something. Therefore, such spot light with strong convergence or directionality is converted into scattered light with high spatial distribution from a surface light source or a tubular light source at the point of use, eliminating physiological discomfort and improving the utilization space. It is often desirable to expand the

The light obtained from a xenon lamp has a wavelength distribution similar to that of sunlight, so it is a preferred light source for living organisms, but in order to incorporate it as a light source in artificial breeding rooms, plant factories, culture equipment, etc. It is desirable to convert spot light into light from a surface light source or a tubular light source.

Fluorescent lamps are inexpensive tubular light sources with relatively good spatial light distribution, but their emission spectra include bright lines, lack of light components necessary for plant growth, and are susceptible to external physical forces. Because it can become a source of ignition and generates heat, its range of use is limited or special protective measures are required.

Therefore, the present invention aims to provide a light source device with a simple structure and low cost that can efficiently convert highly condensing or highly directional light into light with a high spatial distribution from a tubular light source. be.

Furthermore, the present invention aims to provide a manufacturing method that can easily manufacture the above-mentioned light source device.

According to the present invention, the above-mentioned problem is solved by installing a transparent tubular body inside a transparent tubular body whose inner wall surface has a center line average roughness Ra of 0.01 to 0.6 μm. This solution is solved by a light scattering tube filled with a core material having a higher refractive index than the above, with at least one end serving as a light-collecting portion and the peripheral surface serving as a light-diffusing portion.

Highly directional light enters the core material from the light-collecting portion at one or both ends of the diffuser tube.

Since the refractive index of the core material is higher than that of the tubular body, this light is refracted or reflected at the inner wall surface of the tubular body, that is, the contact interface between the tubular body and the core material. , a large amount of light is reflected, and especially when the angle of incidence with respect to the boundary surface exceeds a critical angle, it is totally reflected and travels through the core material while still maintaining its directivity. However, since the boundary surface, that is, the inner wall surface of the tubular body is a rough surface with a center line average roughness Ra of 0.01 to 0.6 μm, the light source incident on the inner wall surface from the core material side is refracted and shaped into the tubular body. Many of them enter the body, and even if they are reflected, they will re-enter other parts of the inner wall surface, where they will be refracted and enter the tubular body. In this way, the light that has been refracted and incident on the tubular body is diffused over the entire surface from the outer peripheral surface of the tubular body. Since these lights are refracted by irregular rough surfaces, they have no directionality, and thus light with high spatial distribution is obtained using the outer peripheral surface of the tubular body as a tubular light source.

However, the surface roughness of the inner wall surface is the center line average roughness Ra
When expressed as , it must be in the range of 0.001 μm to 0.6 μm. When Ra is 0.01 μm or less, it is substantially difficult to extract light from the circumferential surface of the tubular body;
If the diameter is 6 μm or more, the intensity distribution in the longitudinal direction of the light extracted from the circumferential surface of the tubular body will be largely biased, resulting in a lack of practicality. Note that the center line average roughness Ra is one of the display methods often used to numerically display surface roughness (JIS B
0601), the center line of the roughness curve (i.e., the straight line where the area surrounded by this straight line and the roughness curve is equal on both sides of this straight line) is the X axis, and the roughness curve is expressed as y = f (x). When, Ra is expressed in microns as given by the following formula.

The blade is a standard measurement length.

In the above-mentioned diffuser tube, it is preferable to close both ends of the transparent tubular body with a window material in order to hold and protect the core material in a predetermined position.

−〇 − In addition, if the window material at one end is made transparent and this end is used as a lighting part, and the window material at the other end is used as a light reflecting member, there will be no light escaping to the outside from the other end, and the diffuser tube will Since almost all of the incoming light is dissipated from the outer peripheral surface of the tubular body, the light conversion efficiency is increased.

Such a diffuser tube according to the present invention can be manufactured very easily by filling the interior of the tubular body with an uncured core material and then hardening or semi-hardening the core material.

Husband-Yong-1 The present invention will be described below with reference to the drawings.

FIG. 1 is a cross-sectional view schematically showing an embodiment of the present invention.
This diffuser tube 1 is constructed by filling the inside of a transparent tubular body 2 with a core material 3, and the openings at both ends of the tubular body 2 are closed by window materials 4 and 5, respectively. The tubular body 2 is made of a transparent inorganic or organic material, such as glass, quartz, alumina, polyethylene, polypropylene, polyester, polyamide, silicone rubber, polycarbonate, polyvinyl chloride, tetrafluoroethylene, hexafluoropropylene copolymer,
It is made from tetrafluoroethylene perfluoroalkoxyethylene copolymer. The core material 3 is also made of a transparent material, and in addition to plastics, thermoelastomers, and liquid cured materials, liquid materials can also be used as the core material 3. When a liquid material is used as the core material 3, it is necessary to reliably hold the liquid material inside the tubular body 2 for a long period of time, so it is desirable to use a viscous liquid or a semi-solid material. Specifically, polyethylene oxide, polypropylene oxide, polyols such as glycerin, polyol esters, polyol ethers, tris (chloroethyl) phosphate, tris (dichloropropyl)
Phosphate esters such as phosphate, liquid paraffin,
Examples include fluorine oil, silicone oil, polyisobutylene, and polysiloxane-modified polyether.

The core material 3 can also be formed by filling the inside of the tubular body 2 with a curable liquid material in an uncured state and then curing it at room temperature, by heating, with light, with radiation, or the like.

Examples of the curable liquid material include epoxy resin, liquid silicone, polyurethane, and liquid polybutadiene.

By forming the core material 3 in this manner, it is possible to extremely easily manufacture the diffuser tube 1 in which the core material 3 is reliably in close contact with the inner wall surface of the tubular body 2, which has a rough surface, as will be described later.

The window material 4 is made of a transparent material, and has the function of enclosing the core material 3 inside the tubular body 2 and also the function of allowing light to enter the diffuser tube 1 . Materials for the window material 4 include quartz, crown glass, and flint glass.

Examples include chalcogenide glass, sapphire, crystal, polycarbonate, methacrylic resin, and polystyrene resin.

The main purpose of the window material 5 provided on the opposite side of the window material 4 is to seal the core material 3, and its transparency is not a concern, but it can be used when it is desired to extract light not only from the peripheral surface of the diffuser tube 1 but also from the end surface. Alternatively, if it is desired to allow light to enter the diffuser tube 1 from the window material 5 as well, it is made of a transparent material similar to the window material 4.

By the way, the material of the tubular body 2 and the material of the core material 3 have different refractive indexes with respect to the wavelength of transmitted light, and the refractive index of the material of the core material 3 is higher than the refractive index of the material of the tubular body 2. However, the refractive index of the tubular body 2 is the same as that of the core material 3 over its entire thickness direction.
It is not necessary that the refractive index of the material in the vicinity of the inner wall surface 6 in contact with the core material 3 is smaller than the refractive index of the material of the core material 3.

Furthermore, the inner wall surface 6 of the tubular body 2 is formed into a rough surface as shown in an exaggerated manner in FIG. It is stored. Each ray of light that has passed through the window material 4 and entered the diffuser tube 1 takes various routes to the inner part of the core material 3, as illustrated by LllA-21-3 in FIG. During this time, at the interface between the tubular body 2 and the core material 3, that is, at the inner wall surface 6 of the tubular body 2, a part is bent and enters the tubular body 2, and a part is reflected and returns to the core. Proceed through material 3.

The refracted light rays pass through the tubular body 2 in the thickness direction and are dissipated from the outer circumferential surface 7, but the ratio and angle of the refracted light and reflected light are determined by the slope of the local roughness curve of the inner wall where each light ray is incident. As a result, the refracted light from the outer circumferential surface 7 is diffused uniformly in all directions with substantially equal intensity over the entire surface.

However, the surface roughness of the inner wall surface 6 is 0.01 μm in Ra
Below, it is substantially difficult to extract light from the outer circumferential surface 7 of the tubular body 2, and when Ra is 0.6 μm or more, the intensity distribution of the light extracted from the outer circumferential surface 7 of the tubular body 2 in the longitudinal direction becomes large. The surface roughness of the inner wall surface 6 must be within the range of 0.01 μm to 0.6 μm in terms of Ra, since this would result in unevenness and lack of practicality. Such surface roughness can be achieved by subjecting the inner wall surface 6 of the tubular body 2 to mechanical processing such as liquid honing, or
This can be achieved by plasma etching or by appropriately controlling heat shrinkage and other factors during extrusion of the tubular body 2.

FIG. 3 shows an example in which the window material 5 is made of metal and the inner end surface thereof is mirror-finished to form a light-reflecting surface 8. In this way, the light introduced from the window material 4 side and reaching the window material 5 without being extracted from the outer peripheral surface 7 of the rear tubular body 2 is directed into the core material 3 again by the light reflecting surface 8. Since the light is converted into diffused light from the outer circumferential surface 7 via the inner wall surface 6, the light conversion efficiency is increased. The window material 5 is stainless steel or aluminum.

Use metal materials such as copper, brass, and iron. Alternatively, the window material 5 may be made of a material such as glass or resin that is difficult to mirror by simply smoothing itself, and a thin metal film may be formed on the surface by means such as vapor deposition, sputtering, plating, etc. to create a light-reflecting surface. 8 can also be formed.

FIG. 4 shows an example in which a light reflecting film 9 is formed on the outer surface of the window material 5. The material of the window material 5 is transparent quartz or the like, and the light reflecting film 9 is formed by depositing a metal thin film on the end surface of the window material 5 by vapor deposition, sputtering, or the like as described above.
It can be obtained by forming by means such as plating, or by closely adhering a thin film of aluminum or copper to the window material 5.

As shown in Experimental Examples 1 and 2 below, the present inventor prototyped a diffuser tube according to the present invention and confirmed its effects.

Experimental Example 1 As the tubular body 2, a hollow tube made of tetrafluoroethylene-per70-roalkoxyethylene copolymer resin and having an inner diameter of 2 m, an outer diameter of 4 mm, and a length of 300 #11 was used,
After filling this hollow tube with tris (monochloroethyl) phosphate as the core material 3, the diameter of both ends was 3 mm.
, and sealed with a 30 mm long quartz plug. The surface roughness of the inner wall surface of the hollow tube was measured using a stylus type surface roughness meter 5URTRONIC (
Ra = 0.1 (manufactured by Taylor Hobson)
It was 7 μm.

Light from a halogen lamp enters from one end of this diffuser tube,
The brightness of the outer peripheral surface of the diffuser tube was measured using a brightness meter (manufactured by Minolta). Measurement points were placed at 50° intervals from the window material. The results are shown in the upper row of Table 1.

Experimental Example 2 Window material on the side opposite to the incident light side (core material 3 in Fig. 3 above)
), except that a thin aluminum film was formed by sputtering on the end face of a quartz plug with a diameter of 3 an and a length of 30 mm.A diffuser tube similar to that of Experimental Example 1 was manufactured, and the same method as that of Experimental Example 1 was used. Similar measurements were taken. The results are shown in the lower part of Table 1.

This confirmed that a highly bright and homogeneous tubular light source could be obtained by the present invention.

As described above, the diffuser tube according to the present invention has a transparent tubular body whose inner wall surface has a center line average roughness Ra of 0.01 to 0.6 μm. The tube is also filled with a core material having a high refractive index, and at least one end is used as a light-collecting part and the peripheral surface is used as a light-diffusing part, so that with an extremely simple structure, the peripheral surface can be used as a tubular light source for highly condensing or highly directional light. It can be efficiently converted into light with high spatial distribution.

It also has a long lifespan because the core is held in place and protected by the windows at both ends.

Furthermore, by using the window material at one end as a transparent body and the window material at the other end as a light reflecting member, incident light can be converted into light with higher spatial distribution with higher conversion efficiency.

The above-mentioned diffuser tube can be manufactured very easily by filling an uncured core material inside a tubular body and then hardening or semi-hardening the core material.

[Brief explanation of the drawing]

FIG. 1 is a vertical cross-sectional view of a diffuser tube according to an embodiment of the present invention, FIG. 2 is an enlarged vertical cross-sectional view of a part of the diffuser tube with its rough surface exaggerated, and FIGS. Each figure is a longitudinal sectional view similar to FIG. 1 showing another embodiment of the invention. 1... Diffusion tube, 2... Tubular body, 3... Core material, 4
...Window material, 5...Window material, 6...Inner wall surface, 7...
Outer peripheral surface, 8... Light reflecting surface, 9... Light reflecting film.

Claims (4)

[Claims] (1) The surface roughness of the inner wall surface is 0.0 as the center line average roughness Ra.
A light scattering tube comprising a transparent tubular body with a diameter of 1 to 0.6 μm, filled with a core material having a higher refractive index than the tubular body, with at least one end serving as a light-collecting portion and the peripheral surface serving as a light-diffusing portion. (2) Claim 1 in which both ends of the transparent tubular body are closed with a window material.
The diffuser tube described. (3) The diffuser tube according to claim 2, wherein the window material at one end is a transparent body, the end is used as a lighting section, and the window material at the other end is a light reflecting member. (4) The method for manufacturing a diffuser tube according to any one of claims 1 to 3, wherein the interior of the transparent tubular body is filled with an uncured core material, and then the core material is hardened or semi-hardened.