JP3240848B2 - Lighting equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

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

[0002]

2. Description of the Related Art Illumination devices are widely used in construction, civil engineering, roads, railways, automobiles, and the like. For example, automobiles include headlamps, stop lamps, ceiling lamps, dashes. Numerous lighting devices such as various display lamps for boards are installed, and the number of these lighting devices is increasing. For this reason, an illumination system using an optical fiber or 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 temperature rise due to a light source in the vehicle interior.

For example, Japanese Utility Model Laid-Open Publication No. 2-51140 proposes a lighting device in which light from a light source is guided to an illuminated portion by a bundle fiber in which a plurality of fiber strands are converged.

When such a bundle fiber is installed in a vehicle such as an automobile, the inside of the vehicle is narrow and many components are mounted. Therefore, the bundle fiber is bent or meandered so as to wipe between these components. Since it is necessary to dispose them, flexibility is required. On the other hand, in order to efficiently guide a large amount of light from a light source, it is desirable to increase the diameter of the fiber. However, although the above-mentioned optical fiber has excellent light transmittance, it is made of glass or a hard plastic material. Therefore, in order to increase the diameter for transmitting a large amount of light, as described in the above proposal, a diameter of 10 mm is required.
It was necessary to bundle a large number of fibers of about 1000 μm into a bundle fiber.

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

On the other hand, the present applicant has proposed a light guide in which a transparent liquid is used as a core material, a tube having a lower refractive index than the core material is filled with the core material, and both ends are sealed with a transparent window material. (Japanese Patent Laid-Open No. 62-266504). The light guide according to this proposal has excellent flexibility even in the case of a large diameter, has a wide effective light receiving area as compared with a bundle fiber, and is capable of highly efficient light transmission.

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

The present invention has been made in view of such problems, and provides an inexpensive lighting device that can guide and emit a large amount of light with high efficiency, and that is excellent in productivity and inexpensive. It is intended to do so.

[0009]

In order to achieve the above object, the present inventor has set forth a light source and a bent or meandering light source so that a light incident end faces the light source and a light output part is located at a predetermined illumination part. And a light guide that emits light from a light source incident from the light incident end from the light emitting portion, wherein the light guide is formed from a rigid solid transparent material, One long light-transmitting member having a diameter of 5 mm or more, which is formed in a bent or meandering state, and a clad that covers the light-transmitting member formed of a material having a lower refractive index than the light-transmitting member. A lighting device is provided.

[0010]

According to the lighting device of the present invention, the rigid solid long transparent material (core) is molded according to the mode of disposing the light guide in a bent or meandering state between the components. Therefore, there is no need to bundle the fiber core as in the past or to make the core liquid and flexible,
By shaping and molding into a predetermined shape according to the installation situation, a light guide can be formed using a rigid core. For this reason, the restrictions on the core material and the method for manufacturing the light guide are reduced, so that the structure of the light guide is simple, the diameter can be easily increased, the effective light receiving area is wide, the efficiency is high, and the window material is provided. Since it can be formed from a core and a clad without necessity, molding is easy, and it is possible to achieve excellent productivity and economic efficiency.

Since the effective light receiving area of the light guide is large and the efficiency is high, light emitted from the light source efficiently enters the light guide in a large amount from the light incident end of the light guide connected to the light source. The light can be incident, guided to a lighting location inside or outside the vehicle, and emitted from the end or the side of the light guide.

[0012]

An embodiment of the present invention will be described below with reference to the drawings. 1 and 2 show a lighting device 1 mounted on a vehicle such as an automobile. The lighting device 1 includes 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 gas laser, an electroluminescent body, a plasma arc tube, or the like can be used. Above all, a short arc type discharge lamp which has good power efficiency and is suitable for condensing on a light guide is preferable, and a metal halide lamp filled with various gases is preferable.

As shown in FIG. 2, the light guide 3 is composed of a long transparent member 4 made of a rigid solid transparent material.
And a cladding 5 covering the same.

As a material for forming the light transmitting member 4, a transparent material having a higher refractive index than the cladding material is used, 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,
Transparent materials such as fluororesin, polyestercarbonate, norbornene-based resin (ARTON), alicyclic acrylic resin (Optrez), silicone resin, acrylic rubber and silicone rubber are preferred.

Among them, (meth) acrylic resins, polycarbonates, polystyrenes, and norbornene resins are preferable because they have good transparency, low specific gravity, light weight, high impact resistance, and easy processing.

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 light-transmitting member is preferably a circle or an ellipse in terms of high light transmittance, but may be a square, a rectangle, or another polygon.

In this case, the diameter of the light transmitting member 4 is set to be as large as 5 mm or more, preferably 7 mm or more, more preferably 10 mm or more, in order to conduct and emit a large amount of light with high efficiency. is there.

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, polymethyl methacrylate, polyvinyl chloride, polyvinylidene chloride, polyvinyl acetate, polyethylene-vinyl acetate copolymer, polyvinyl alcohol, polyethylene-polyvinyl alcohol copolymer, and fluororesin. , Silicone resin, natural rubber, polyisoprene rubber, polybutadiene rubber, styrene-butadiene copolymer, butyl rubber, halogenated butyl rubber, chloroprene rubber,
Acrylic rubber, EPDM, acrylonitrile-butadiene copolymer, fluorine rubber, silicone rubber, and the like are included.

Among them, silicone polymers having a low refractive index, such as polydimethylsiloxane polymer and fluorosilicone polymer, polytetrafluoroethylene (PTFE), ethylene tetrafluoride-hexafluoropropylene copolymer (FEP), Fluoroethylene-perfluoroalkoxyethylene copolymer (PFE), polychlorotrifluoroethylene (PCTFE), ethylene tetrafluoride
Ethylene copolymer (ETFE), polyvinylidene fluoride, polyvinyl fluoride, vinylidene fluoride
Trifluoroethylene chloride copolymer, vinylidene fluoride-propylene hexafluoride copolymer, vinylidene fluoride-propylene hexafluoride-ethylene tetrafluoride terpolymer, ethylene tetrafluoride propylene rubber, fluorine-based heat Particularly preferred are fluoropolymers such as plastic elastomers. These materials can be used alone or as a blend.

The clad material is coated on the outer periphery of the light-transmitting member. The method includes solution coating, two-layer extrusion with the light-transmitting member, two-color injection molding, vapor deposition, coating by plasma, and the like. There is a treatment with gas. Further, a method in which a clad material formed in a tubular shape is covered by heat shrinkage or adhesion can also be adopted.

In the present invention, the light guide 3 composed of the light transmitting member 4 and the clad 5 has one end (light incident end) 4a of the light transmitting member 4 arranged to face the light source 2, and The light enters the light transmitting member 4 from the light incident end 4a, and the light emitting portion 4b of the light transmitting member 4 (the other end in FIG. 1).
Is disposed in a lighting section of the vehicle, and the light transmitted through the light transmitting member 4 is emitted from the light emitting section 4b to illuminate a required lighting location inside or outside the vehicle. in this case,
The light guide 3 is disposed to bend or meander in the vehicle according to the location where the light guide 3 is disposed.
Is preformed into a bent or meandering state according to the installation location,
The light guide 3 thus formed is provided. As a method for forming the bent or meandering state, a method in which a long linear light transmitting member is covered with a clad and then bent by a press, a bending device (bender), or the like can be adopted. Moreover, after bending the long linear light-transmitting member, it may be coated with a clad.

In the present invention, the bending or meandering mode of the light guide 3 is selected according to the installation location and the installation location of the light guide 3 as described above. Therefore, the bending or meandering mode shown in FIG. For example, the light guide 3 may be bent in a manner as shown in FIG. 3. However, when the light guide 3 is bent, the light guide 3 is bent more than the minimum radius of curvature obtained by the following calculation method in terms of light transmission efficiency. It is desirable to make it.

For light incident on the bent portion of the light guide, θ
Angle core - at an incident amount I ₀ to cladding interface, when the reflected N times with the bent portion, the light transmission quantity I between the core
Is represented by the following equation.

I = I₀R (θ)^N= I₀R (θ)^2N R (θ) : Core reflectance N: number of reflections r (θ) : Reflection coefficient Here, the reflection coefficient r (θ) is expressed by Fresnel's formula and Sn
It is determined by the formula of Le.

R (θ) = (N₁cos θ-n_Twocosγ) / (n₁cos θ + n_Twocosγ) ... sinθ / sinγ = n₁/ N_Two … N₁: Refractive index n of the core_Two: Refractive index of the cladding θ: Incident angle γ: Refractive angle Also, the incident angle θ is determined by the formula, but it is incident on the center line.
For light, that is, when x = 0 and y = 0, the equation becomes
You.

[0029]

(Equation 1)

Further, the number of reflections can be obtained by an equation. N = [(180−θ) / 2θ] +1 In the case of 90 ° bending, [(90−θ) / 2θ] +
It becomes 1. Thus, the light transmittance L (= I
/ I ₀ ) can be obtained from 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 varied depending on 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 bending radius is about 5.6 cm.

It is preferable to provide an ultraviolet protection film, an infrared reflection film or an antireflection film for visible light on the light incident end 4a of the light guide 3.

Further, the light emitting portion 4b can be formed in an appropriate shape according to the illumination location. For example, as shown in FIG.
The light-emitting portion (light-emitting end) 4b can be formed in a shape such as a truncated cone having a large diameter at the front end surface, or the light-emitting end surface can be spherical, hemispherical, or the like.
It can be formed in 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 increase the incident efficiency.

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

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 material can be coated on the clad material by coating, extruding, winding a tape-like material, heat-shrinking treatment, or the like.

Further, a metal material such as SUS, aluminum, copper, iron or the like, or the above-mentioned polymer material is formed into a pipe shape, a bellows tube,
The light guide may be inserted into a spiral wire. Furthermore, metal material is plated around the clad material,
It can also be coated 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.

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

Next, an experimental example will be described. [Experimental example] PMMA having a refractive index of 1.49 was used with a diameter of 5, 7, 1
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, about 100
Bending while heating 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 for 2000 lumens of light emitted from the lamp.

[0041]

[Table 1]

For comparison, PMMA having a diameter of 0.75 mm was used.
About 400 optical fibers bundled, diameter 10mm, length 1
m, and a light transmission characteristic was measured in the same manner as described above. As a result, the output light amount is 8
At a lumen of 00, the transmittance was 40%.

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

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

FIG. 6 shows an example in which the lighting device of the present invention is used for lighting in a trunk room. Light incident from a dedicated light source disposed in the vehicle or an existing light source such as a headlamp or a vehicle side light is guided to a trunk room by a light guide, and can be emitted from the tip or side surface of the light guide. 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.

Other than this, in the dashboard,
It can also be used for lighting meters, lighting various switches, lighting glove boxes and ashtrays, and lighting keyholes. Outside the car, license plate lighting,
It can also be used as various types of lighting and / or light emitters, such as backlighting license plates, lighting various emblems, emitting light at the tip of an antenna pole, and linearly emitting a corner pole, bumper or mall.

[0047]

According to the present invention, it is possible to guide and emit a large amount of light with high efficiency and to bend or meander in advance in an arrangement state according to the installation location in the vehicle.
It can be easily incorporated into a vehicle, and the light emitting portion can be easily formed into a shape suitable for the purpose of lighting, and is excellent in productivity and inexpensive.

[Brief description of the 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 for explaining an example of a use mode of the present invention.

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

FIG. 7 is a perspective view illustrating another example of a 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 refractive index of the cladding is 1.404.

[Explanation of symbols]

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

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) G02B 6/00 G02B 6/02 F21V 8/00

Claims (2)

(57) [Claims] 1. A light source (2) and a light-entering end (4a) are arranged to bend or meander such that a light-emitting part (4b) is located at a predetermined illumination part, facing the light source (2). A light guide (3) for emitting light from the light source (2) incident from the light incident end (4a) from the light emitting portion (4b), wherein the light guide (3) is rigid. One long translucent member (4) having a diameter of 5 mm or more, which is formed of a solid transparent material and is formed in a bent or meandering state, and a material having a lower refractive index than the translucent member (4). An illumination device, comprising: a clad (5) that covers the formed light-transmitting member (4). 2. The lighting device according to claim 1, wherein the lighting device is for a vehicle.