JPH0843638A - Illuminating device - Google Patents

Abstract

PURPOSE:To obtain an illuminating device which guides and projects much light with high efficiency, which is previously bent or set meandered into a disposed state in accordance with a set place in a vehicle to be easily assembled in the vehicle, whose light outgoing part is easily formed into a shape in accor dance with the purpose of illumination, and which is made excellent in productiv ity and low-priced. CONSTITUTION:This illuminating device is provided with a light source 2, and a light guide 3 disposed so that a light incident end 4a is opposed to the light source 2 and the light outgoing part 4b is bent or meandered to be positioned at a specified illuminating part and projecting the light from the light source 2, which is made incident from the light incident end 4a, from the light outgoing part 4b. The light guide 3 is constituted of a long light transmissive member 4 which is formed out of a transparent material in a rigid solid state and embossed to be a bent or meandering state, and a clad 5 which is formed out of a material having a lower refractive index than the member 4 and with which the member 4 is coated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lighting device using a light guide for transmitting light from a light source to a predetermined lighting portion in a vehicle.

[0002]

2. Description of the Related Art Lighting devices are widely used in construction, civil engineering, roads, railways, automobiles, etc. For example, in automobiles, headlamps, stop lamps, ceiling lamps, dash are used. Many lighting devices such as various display lamps on the board are installed, and the number of these lighting devices is increasing. Therefore, an illumination system using an optical fiber and a light guide is being proposed for the purpose of reducing the weight, volume, and power consumption of the illumination device in the entire vehicle and preventing the temperature rise due to the light source in the vehicle interior.

For example, Japanese Utility Model Laid-Open No. 2-51140 proposes an illuminating device which guides light from a light source to an illuminating place by a bundle fiber in which a plurality of fiber element wires are converged.

When such a bundle fiber is arranged in a vehicle such as an automobile, since the inside of the vehicle is narrow and a large number of parts are mounted, the bundle fiber bends or meanders so as to penetrate between the parts. Since it needs to be arranged, it is required to have flexibility. On the other hand, in order to efficiently guide a large amount of light from the light source, it is desirable to increase the diameter of the fiber. However, although the above-mentioned optical fiber has excellent optical transparency, it is made of glass or a hard plastic material, and therefore loses its flexibility when made thick. Therefore, in order to increase the diameter for transmitting a large amount of light, the diameter of 10
It was necessary to bundle a large number of fibers of about 1000 μm to form a bundle fiber.

However, no matter how densely the optical fibers are bundled, a gap remains between the fibers, so that there is a problem that the effective light receiving area when light is incident becomes narrow and the efficiency is poor. For example, the core diameter is 80 μm and the fiber diameter is 1
In the case of a bundle fiber in which optical fiber strands of 00 μm are bundled, the space between fibers is 25%, the clad part is 25%, and the area of the core part that actually transmits light is 50%.
Therefore, the efficiency of light incidence is poor. Also,
Since the optical fiber strand itself is expensive and the cost for processing it into a bundle fiber is high, the bundle fiber has been very expensive and is not yet adopted in the lighting system for automobiles.

On the other hand, the present applicant uses a transparent liquid as a core material, fills a tube having a lower refractive index than the core material with the core material, and seals both ends with transparent window materials. Has been proposed (JP-A-62-266504). The optical guide according to this proposal has excellent flexibility even when it has a large diameter, has a larger effective light receiving area than the bundle fiber, and enables highly efficient optical transmission.

However, the optical guide using this liquid as a core material may have a risk of leakage of the core liquid due to external damage, and also has a large number of parts such as window materials at both ends and metal fittings for fixing the window material, so that the cost is still high. Met.

The present invention has been made in view of these problems, and provides an inexpensive lighting device capable of guiding and emitting a large amount of light with high efficiency, and having excellent productivity. The purpose is to do.

[0009]

In order to achieve the above object, the present invention bends or meanders so that a light source and a light incident end face the light source and a light emitting portion is located at a predetermined illumination portion. In an illuminating device provided with a light guide that emits light from a light source incident from the light incident end from the light emitting portion, the light guide is formed from a rigid solid transparent material, and the bending or (EN) Provided is an illuminating device comprising a long light-transmitting member shaped in a meandering state and a clad formed of a material having a refractive index lower than that of the light-transmitting member and covering the light-transmitting member.

[0010]

According to the illuminating device of the present invention, a rigid solid elongated transparent material (core) is molded in accordance with the manner in which the light guides are arranged in a bent or meandering state between parts. Therefore, it is not necessary to bundle the fibrous cores or to make the cores liquid to be flexible as in the conventional case,
The light guide can be formed by using the rigid core by molding and molding into a predetermined shape according to the installation situation. Therefore, the restrictions on the core material and the manufacturing method of the light guide are reduced, so that the structure of the light guide is simple, the aperture can be easily increased, the effective light receiving area is wide, and the efficiency is high, and the window material is provided. Since it can be formed from the core and the clad without any need, it can be easily molded, and can be excellent in productivity and economical.

Since the light receiving area of the light guide is large and the efficiency is high, the light emitted from the light source is efficiently converted into a large amount from the light receiving end of the light guide connected to the light source. The light can be made incident and guided to an illumination location inside or outside the vehicle and emitted from the end or the side surface of the light guide.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. 1 and 2 show an illuminating device 1 mounted on a vehicle such as an automobile. The illuminating device 1 is composed of a light source 2 and a light guide 3.

Here, as the light source 2, an incandescent lamp, a fluorescent tube, a halogen lamp, a discharge lamp, a light emitting diode, a semiconductor or a gas laser, an electroluminescent body, a plasma arc tube or the like can be used. Above all, a short arc type discharge lamp having good power efficiency and suitable for focusing on a light guide is preferable, and a metal halide lamp filled with various gases is preferable.

The light guide 3 is, as shown in FIG. 2, a long transparent member 4 made of a rigid solid transparent material,
It is composed of a clad 5 which covers this.

A transparent material having a refractive index higher than that of the clad material is used as the material for forming the transparent member 4, and it can be selected from inorganic glass, plastic, elastomer and the like according to the purpose.

Specific examples include quartz glass, Pyrex glass, multi-component glass, polystyrene, styrene / methyl methacrylate copolymer, (meth) acrylic resin,
Polymethylpentene, allyl glycol carbonate resin, spirane resin, amorphous polyolefin, polycarbonate, polyamide, polyarylate, polysulfone, polyallylsulfone, polyethersulfone, polyetherimide, polyimide, diallylphthalate,
A transparent material such as a fluororesin, a polyester carbonate, a norbornene-based resin (ARTON), an alicyclic acrylic resin (Optretz), a silicone resin, an acrylic rubber, or a silicone rubber is preferable.

Among them, (meth) acrylic resin, polycarbonate, polystyrene and norbornene-based resin are preferable in that they have good transparency, have a small specific gravity and are lightweight, are strong against impact and are easy to process.

These transparent materials can be processed into a desired shape by extrusion molding, injection molding, compression molding or the like. The cross-sectional shape of the translucent member is preferably circular or elliptical in terms of high light transmittance, but may be square, rectangular, or other polygonal shape.

In this case, the larger the diameter, the higher the efficiency, but it is generally 5 mm or more, more preferably 7 mm or more, and further preferably 10 mm or more.

The material of the clad 5 can be selected from materials having a low refractive index, and examples thereof include organic materials such as glass, plastics and elastomers, and gases such as air.

Specific examples thereof include polyethylene, polypropylene, polymethylmethacrylate, polyvinyl chloride, polyvinylidene chloride, polyvinyl acetate, polyethylene-vinyl acetate copolymer, polyvinyl alcohol, polyethylene-polyvinyl alcohol copolymer, fluororesin. , Silicone resin, natural rubber, polyisoprene rubber, polybutadiene rubber, styrene-butadiene copolymer, butyl rubber, halogenated butyl rubber, chloroprene rubber,
Examples thereof include acrylic rubber, EPDM, acrylonitrile-butadiene copolymer, fluororubber and silicone rubber.

Among these, silicone polymers having a low refractive index, such as polydimethylsiloxane polymer and fluorosilicone polymer, polytetrafluoroethylene (PTFE), tetrafluoroethylene-hexafluoropropylene copolymer (FEP), four Fluorinated ethylene-perfluoroalkoxyethylene copolymer (PFE), polychlorotrifluoroethylene (PCTFE), tetrafluoroethylene-
Ethylene copolymer (ETFE), polyvinylidene fluoride, polyvinyl fluoride, vinylidene fluoride
Ethylene trifluoride chloride copolymer, vinylidene fluoride-hexafluoropropylene copolymer, vinylidene fluoride-propylene hexafluoride-tetrafluoroethylene terpolymer, tetrafluoroethylene propylene rubber, fluorine-based heat A fluoropolymer such as a plastic elastomer is particularly preferable. These materials can be used alone or as a blend.

The clad material is coated on the outer periphery of the transparent member, and the method includes solution coating, two-layer extrusion with the transparent member, two-color injection molding, vapor deposition, coating by plasma, etc., and reactivity. There is gas treatment. Alternatively, a method of covering the tubular clad material by heat shrinkage or adhesion may be used.

In the present invention, the light guide 3 composed of the light transmitting member 4 and the clad 5 is arranged such that one end (light receiving end) 4a of the light transmitting member 4 faces the light source 2 and Light is made to enter the transparent member 4 through the light entrance end 4a, and at the same time, the light exit part 4b of the transparent member 4 (the other end in FIG. 1).
Is arranged in the illumination section of the vehicle, and the light transmitted through the translucent member 4 is emitted from the light emitting section 4b so as to illuminate a desired illumination location inside or outside the vehicle. in this case,
The light guide 3 is arranged in a vehicle by bending or meandering in accordance with the installation location. In the present invention, the light guide 3 is provided.
Pre-molded into a bent or meandering state according to this installation location,
The light guide 3 thus shaped is arranged and the shaped light guide 3 is arranged. As a method of molding in this bent or meandering state, a method of covering a long linear light-transmitting member with a clad and then bending it with a press, a bending device (bender) or the like can be adopted. Alternatively, the long linear translucent member may be bent and then covered with a clad.

In the present invention, the bending or meandering mode of the light guide 3 is selected depending on the installation location and installation location of the light guide 3 as described above, and therefore, the bending or meandering mode shown in FIG. The shape is not limited, and it can be modeled, for example, as shown in FIG. 3. However, when the light guide 3 is bent, in terms of light transmission efficiency, the light guide 3 is bent more than the minimum radius of curvature obtained by the following calculation method. It is desirable to let

For the light incident on the bent portion of the light guide, θ
When an incident amount I ₀ is incident on the core-clad interface at an angle of I and is reflected N times at the bent portion, the amount of light transmission I between the cores is I.
Is represented by the following formula.

I = I₀R (θ)^N= I₀R (θ)^2N R (θ) : Core reflectance N: Number of reflections r (θ) Where: reflection coefficient r (θ) is the Fresnel equation and
It is determined by the formula of Le.

R (θ) = (N₁cos θ-n₂cosγ) / (n₁cos θ + n₂cosγ) ... sin θ / sinγ = n₁/ N₂ ... n₁: Refractive index of core n₂: Cladding refractive index θ: Incident angle γ: Refraction angle Also, the incident angle θ is determined by the formula, but it is incident on the center line.
In the case of light, that is, x = 0, y = 0, the formula becomes the formula '
It

[0029]

[Equation 1]

Further, the number of reflections can be calculated by the formula. N = [(180−θ) / 2θ] +1 In the case of 90 ° bending, [(90−θ) / 2θ] +
It becomes 1. In this way, the light transmittance L (= I
/ I ₀ ) can be obtained by the radius a of the core of the light guide, the radius of curvature R, and the refractive indices n ₁ and n ₂ of the core and the clad. In this case, the curvature is set so that the light transmittance L becomes 1. Radius R
It is desirable to decide.

FIG. 8 shows the relationship between the minimum bending radius and the core refractive index when the refractive index of the cladding is 1.404. The minimum bending radius can be changed according to the core diameter of the light guide. . For example, if the core diameter is 8 mm and the refractive index is 1.5, the minimum bend radius is about 5.6 cm.

It is preferable that the light entrance end 4a of the light guide 3 is provided with an ultraviolet ray prevention film, an infrared ray reflection film, or an antireflection film for visible light.

Further, the light emitting portion 4b can be formed in an appropriate shape according to the illuminated place. For example, as shown in FIG.
The light output portion (light output end) 4b can be formed in a truncated cone shape having a large diameter at the tip surface, or the light output end surface can be spherical, hemispherical,
It can also be formed into a convex shape or a concave shape.

Similarly, the light incident end 4a is preferably formed in a truncated cone shape or the like in order to improve the incidence efficiency.

The outer peripheral portion of the light guide can be covered and protected with an appropriate covering material according to the purpose. This coating material can be selected from plastic, elastomer, metal, glass and inorganic materials.

Specifically, polyamide, epoxy resin,
Polymers such as polyvinyl chloride, polycarbonate, polystyrene, fluororesin, butyl rubber, halogenated butyl rubber, polyethylene, polypropylene, polyurethane, hydrochloric acid rubber, natural rubber, polyisoprene rubber, polybutadiene rubber, chloroprene rubber, acrylic rubber, EPDM, fluororubber, etc. The clad material can be coated with the material by coating, extrusion molding, winding a tape-shaped material, heat shrinking treatment, or the like.

Further, metal materials such as SUS, aluminum, copper, iron, etc., or the above-mentioned polymer materials are pipe-shaped, bellows-shaped,
The light guide may be inserted into the spiral wire. Furthermore, a metal material is plated on the outer circumference of the clad material,
It is also possible to coat with a metal film by vapor deposition, sputtering or the like.

These coating materials can be used alone or as a composite with other materials.

Further, the above-mentioned coating material can be provided not only for protecting the light guide but also for the purpose of shielding light or causing only a required portion to emit light. For example, if a hole is made in the required portion of the above-mentioned covering material or if it is made transparent, light leaks out from that portion, and a large number of spot-shaped or line-shaped luminous bodies can be obtained.

Next, an experimental example will be shown. [Experimental Example] PMMA having a refractive index of 1.49 was used as a diameter 5, 7, 1
The rod was extruded to 0 mm, and the surface of the extruded rod was coated with a room temperature curable liquid dimethyl silicone rubber (refractive index 1.405) and then cured overnight. afterwards,
Cut to 1 m, smooth both ends by polishing,
It was bent while being heated to ° C. Next, the light transmission characteristics were measured using a 150 W metal halide lamp as a light source. Table 1 shows the results of the amount of light emitted from the light guide and the transmittance with respect to the amount of light emitted from the lamp of 2000 lumens.

[0041]

[Table 1]

For comparison, PMMA having a diameter of 0.75 mm
About 400 optical fibers bundled, diameter 10 mm, length 1
A bundle type light guide having m was manufactured, and the light transmission characteristics were measured in the same manner as above. As a result, the amount of emitted light is 8
At 00 lumens, the transmission was 40%.

Therefore, as can be seen from the above experiments, the illumination device of the present invention exhibits excellent light transmission characteristics.

The lighting device of the present invention is provided in a vehicle and can be used for various lighting inside or outside the vehicle. For example, FIG. 5 shows an example in which the lighting device of the present invention is used for various lighting on a ceiling. Light incident from a dedicated light source placed inside the vehicle or an existing light source such as a headlamp is guided to the ceiling by a light guide, and is made to emit light at a predetermined location on the ceiling, so that a map lamp, a room lamp, and a reading lamp. It can be used as

FIG. 6 shows an example in which the lighting device of the present invention is used for lighting in a luggage compartment. Light incident from an exclusive light source arranged in the vehicle or an existing light source such as a headlamp or a side light can be guided to the trunk room by the light guide and emitted from the tip or the side surface of the light guide. Further, FIG. 7 shows an example in which the lighting device of the present invention is used for a head lamp, a direction indicator lamp, and the like.

Besides this, in the dashboard,
It can also be used for lighting meters, lighting various switches, lighting glove boxes and ashtrays, and lighting keyholes. Also, outside the car, the license plate lighting,
It can also be used as various lights and / or light emitters such as a backlight for license plates, lighting for various emblems, light emission at the tip of an antenna pole, and linear light emission for corner poles, bumpers and moldings.

[0047]

As described above, according to the present invention, a large amount of light can be guided and emitted with high efficiency, and it is bent or meandered in advance according to the installation location in the vehicle.
It can be easily incorporated into a vehicle, the light emitting portion can be easily formed into a shape according to the purpose of illumination, and the productivity is excellent and the cost is low.

[Brief description of drawings]

FIG. 1 is a perspective view showing an embodiment of the present invention.

FIG. 2 is a sectional view taken along line AA of FIG.

FIG. 3 is a plan view showing another example of the light guide of the present invention.

FIG. 4 is a plan view showing another example of the light guide of the present invention.

FIG. 5 is a partially cutaway side view illustrating an example of a usage mode of the present invention.

FIG. 6 is a perspective view illustrating another example of the use mode of the present invention.

FIG. 7 is a perspective view illustrating another example of the use mode of the present invention.

FIG. 8 is a graph showing the relationship between the core refractive index and the minimum radius of curvature when the cladding refractive index is 1.404.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Lighting device 2 Light source 3 Light guide 4 Light transmitting member 4a Light entrance end 4b Light exit part 5 Cladding

Claims (2)

[Claims] 1. A light source (2) is bent or meandered so that a light incident end (4a) faces the light source (2) and a light emitting portion (4b) is located at a predetermined illumination portion. A light guide (3) for causing the light from the light source (2) incident from the light incident end (4a) to be emitted from the light emitting portion (4b), the light guide (3) is rigid. The long light-transmitting member (4) formed of a solid transparent material and shaped in the bent or meandering state, and the light-transmitting member (4) made of a material having a lower refractive index than the light-transmitting member (4). An illuminating device comprising a clad (5) for covering 4). 2. The lighting device according to claim 1, wherein the lighting device is for a vehicle.