JP2004342411A - Illuminating device and illuminating system including the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an illuminating device which can easily control a light distribution characteristic using a light-emitting element and a phosphor. <P>SOLUTION: The illuminating device comprises the light-emitting element (102), a fiber-like light guide body (100) which guides light introduced from the light-emitting element and radiates it at least from a part thereof, a translucent guard vessel (101) which includes the phosphor for absorbing the light radiated from the light guide body and radiating the fluorescence of a different wavelength, and houses the light-emitting element and the fiber-like light guide body, and electrical structures (103; 105) which supply electric power to the light-emitting element. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an improvement of a point-shaped lighting device including a semiconductor light emitting device and a phosphor that can emit light of various colors by converting the wavelength of light from the device.
[0002]
[Prior art]
Lighting devices can be broadly classified into point-like, linear, and planar lighting devices. 2. Description of the Related Art As a point illumination device used in conventional general illumination, there is an incandescent lamp that obtains visible light from a filament that is incandescent by a current in a vacuum glass bulb filled with an argon gas or the like. However, in the case of an incandescent light bulb, most of the electric energy is lost as heat and only a part thereof is radiated as light, so that luminous efficiency is low and power consumption is large.
[0003]
In recent years, a white light emitting diode element has been developed in which a resin in which a phosphor that absorbs ultraviolet light and emits visible fluorescent light (red, blue, green) is dispersed is covered with the ultraviolet light emitting diode element. A white light-emitting diode element that emits white light by using a complementary color relationship by covering a blue light-emitting diode element with a resin in which a phosphor that absorbs blue light and emits visible fluorescent light (yellow) is covered. (See, for example, Japanese Patent Application Laid-Open No. 2000-156526 in Patent Document 1).
[0004]
Such a white light emitting diode element has an advantage that power consumption can be suppressed as compared with an incandescent light bulb since loss due to heat generation is small.
[0005]
Further, as an illuminating device replacing the incandescent lamp, a white illuminating device using a semiconductor laser element, a lens, and a phosphor is disclosed in Japanese Patent Application Laid-Open No. 7-282609 of Patent Document 2.
[0006]
[Patent Document 1]
JP 2000-156526 A
[Patent Document 2]
JP-A-7-282609
[Problems to be solved by the invention]
In a white light emitting diode element as disclosed in Patent Literature 1, since the light emitted from the light emitting element has a strong directivity, light can be applied only to a comparatively narrow area. Also, in the lighting device disclosed in Patent Document 2, the emission angle of the light emitted from the semiconductor laser element is narrow at most about 20 to 30 degrees. Irradiation.
[0009]
However, in general, a light beam emitted from a light emitting element such as a semiconductor laser element has a Gaussian distribution in which the light intensity is very strong at the center and becomes weaker toward the periphery. That is, since the light applied to the phosphor affects the Gaussian distribution, the distribution of the intensity of the fluorescence emitted from the phosphor to the space is not uniform. For this reason, it is difficult to control the light distribution characteristics in a point lighting device using a light emitting element and a phosphor.
[0010]
In view of the state of the prior art as described above, an object of the present invention is to provide a lighting device that can easily control light distribution characteristics while using a semiconductor light emitting element and a phosphor.
[0011]
[Means for Solving the Problems]
A lighting device according to the present invention includes a light emitting element, a fiber light guide that guides light introduced from the light emitting element and emits light from at least a part thereof, and absorbs light emitted from the light guide. It is characterized by including a phosphor that emits fluorescence of another wavelength, a light-transmitting protective container containing a light-emitting element and a fibrous light guide, and an electrical structure for supplying power to the light-emitting element.
[0012]
Note that at least a part of the light emitting region of the fibrous light guide may include any of a spiral shape, a parabolic shape, and a linear shape. Further, the phosphor may be dispersed and included in the constituent material of the translucent protective container.
[0013]
A light diffusing structure that partially scatters light propagating in the light guide may be provided in the light emitting region of the fibrous light guide. In that case, the fibrous light guide may include a core and a cladding, and a light diffusing structure may be provided in at least a partial region of the core. Further, the fiber light guide may include a core and a clad, and a light diffusion structure may be provided in at least one region of the clad where evanescent light exists. Further, the fibrous light guide may include a core and a cladding, and the light emitting area of the light guide may be shaped to have a curvature that causes the emission of a portion of light propagating in the core.
[0014]
The lighting device may include a plurality of fiber light guides. Further, it is preferable that an optical film that propagates through the fibrous light guide is provided on an area other than the area where light from the light emitting element is incident on the end face of the fibrous light guide. Furthermore, a light emitting element may be arranged on each of both end faces of the fibrous light guide. Either a semiconductor laser device or a light emitting diode device may be used as the light emitting device.
[0015]
In the lighting system including the lighting device as described above, a drive circuit that supplies drive power to an electrical structure that supplies power to the light-emitting element can be preferably connected. In addition, a control circuit may be further provided, in which a conductive film is formed on at least a part of the surface of the light-transmitting protective container, and a break of the conductive film is detected to control power supplied to the light emitting element. .
[0016]
BEST MODE FOR CARRYING OUT THE INVENTION
(Embodiment 1)
1 and 2, a lighting device according to a first embodiment of the present invention is schematically illustrated. FIG. 1 shows a state in which a part of the lighting device has been cut away, FIG. 2 (a) shows a part cut out from the optical fiber in FIG. 1 in a perspective view, and FIG. 2 shows a cross section of the optical fiber. In the drawings of the present application, the same reference numerals represent the same or corresponding parts.
[0017]
In FIG. 1, a GaN-based light emitting diode element 102 that emits light at a wavelength of 410 nm and an optical fiber 100 that transmits light from the light emitting diode element are optically coupled. The GaN-based light-emitting diode element and the optical fiber may be directly coupled, or may be optically coupled via a lens or the like. In FIG. 1, the GaN-based light emitting diode element 102 and the optical fiber 100 are fixed by a resin 106.
[0018]
A wire 103 is wired from the power supply terminal 105 to the GaN-based light emitting diode element 102, and power is supplied to the light emitting diode element 102 by such an electrical structure.
[0019]
As illustrated in FIG. 2, the optical fiber 100 includes a core 200 and a clad 202 made of a resin that guides light. A light diffusion structure 201 including, for example, TiO ₂ particles is provided in a part of the core 200 to partially scatter the guided light.
[0020]
As shown in FIG. 1, an optical film 104 that reflects light so as to prevent radiation loss of guided light is provided on the end face of the optical fiber 100 on which the GaN-based light emitting diode element is not disposed. Is provided. The film configuration of the optical film 104 can be designed by a general method using the principle of interference that causes light reflection in the film.
[0021]
As understood from the above, the light from the GaN-based light emitting diode element 102 is radiated to the periphery while propagating in the spiral optical fiber 100.
[0022]
Further, the periphery of the fiber light guide 100 is, for example, red (Y ₂ O ₂ S: Eu ³⁺ ), green (ZnS: Cu, Al), blue ((Sr, Ca, Ba, Mg) ₁₀ (PO ₄ ) ₆ ): covered with a ball-shaped protective shell 101 made of an acrylic resin in which a phosphor made of Eu ²⁺ ) is dispersed. Then, when light is irradiated from the fiber light guide 100 to the phosphor-containing shell 101, white light is emitted from the phosphor-containing shell 101 into space.
[0023]
By forming the optical fiber 100 in a spiral shape in this manner, light from the light emitting element 102 can be uniformly emitted from the fiber in all directions, that is, the ball-shaped shell 101 containing the phosphor is irradiated almost uniformly. It becomes possible. Therefore, as represented by the arrow in FIG. 1, it is possible to realize a lighting device with good uniformity of light distribution characteristics.
[0024]
The number of turns of the spiral shape and the spiral diameter of the optical fiber 100 can be arbitrarily selected so as to obtain desired light distribution characteristics. Further, it is also possible to provide the light diffuser 201 only in the helical portion and make the other portion into an optical fiber structure that does not emit light.
[0025]
(Embodiment 2)
3 and 4, a lighting device according to Embodiment 2 of the present invention is schematically illustrated. FIG. 3 shows a state in which a part of the illumination device is cut off, and FIG. 4A schematically shows a light intensity distribution emitted from an optical fiber when the illumination device in FIG. 3 is viewed from above. FIG. 4B schematically shows the light intensity distribution emitted from the optical fiber when the lighting device of FIG. 3 is viewed from the left or right side.
[0026]
The features of the second embodiment as compared with the first embodiment are that at least a part of the light emission region of the optical fiber 100 is parabolic, and that the GaN-based semiconductor device is used instead of the GaN-based light-emitting diode element 102. That is, the laser element 300 is used. The direction of the plane including the parabola is indicated by a bidirectional arrow in FIG.
[0027]
By adopting the configuration as in the second embodiment, it is possible to realize a light distribution characteristic in which the light intensity decreases in the order of the region 400, the region 401, and the region 402, as shown in FIG. . That is, in the second embodiment, it is possible to realize a lighting device capable of easily controlling the light distribution characteristics.
[0028]
(Embodiment 3)
FIG. 5 schematically illustrates a lighting device according to Embodiment 3 of the present invention, and illustrates a state where a part of the lighting device is cut away. A feature of the third embodiment as compared to the first embodiment is that at least a part of the light emitting portion in the optical fiber 100 is linear.
[0029]
By forming the light emitting portion of the optical fiber 100 into a linear shape as in the third embodiment, as shown by an arrow in FIG. Only can emit strong light. That is, even with the configuration of the third embodiment, it is possible to realize a lighting device capable of easily controlling the light distribution characteristics.
[0030]
(Embodiment 4)
The lighting device according to the fourth embodiment of the present invention is similar to the above-described first to third embodiments, except that the structure of the optical fiber included therein is partially changed. 6 and 7 illustrate the structure of an optical fiber used in the lighting device according to the fourth embodiment in a schematic cross-sectional view.
[0031]
The optical fiber of FIG. 6 includes a core 200 that guides light and a clad 202. In the cladding 202, an evanescent wave (light leaking from the core) near the outer periphery of the core 200 exists in an area 201 where the evanescent wave is transmitted. For scattering, a light diffusion structure including, for example, TiO ₂ particles is formed. Light introduced from a GaN-based light-emitting diode element or a semiconductor laser element disposed on the end face of such an optical fiber can be radiated around the optical fiber while propagating in the optical fiber.
[0032]
The structure as shown in FIG. 6 includes the light diffusion structure 201 only in a region where the light intensity is low (evanescent wave region) and has a small scattering coefficient with respect to the propagating light. It is preferable as a structure for radiating light.
[0033]
The optical fiber of FIG. 7 is similar to that of FIG. 6, except that the acrylic resin layer 101 in which the phosphor is dispersed is formed on the outer peripheral surface of the clad 202. When such an optical fiber of FIG. 7 is used, it is not necessary to disperse the phosphor in the material of the ball-shaped protective shell 101 as in the first embodiment.
[0034]
By using the optical fiber as shown in FIG. 6 or FIG. 7 as in the fourth embodiment, the light distribution characteristics can be easily controlled as in the other embodiments. A lighting device can be realized.
[0035]
(Embodiment 5)
8, 9, and 10, a lighting device according to Embodiment 5 of the present invention is schematically illustrated. 8 shows a state in which a part of the lighting device has been cut away, FIG. 9 illustrates the structure of the optical fiber in FIG. 8, and FIG. 10 shows the optical fiber and the semiconductor laser device in FIG. 2 illustrates an optical coupling portion.
[0036]
In the lighting device of FIG. 8, laser light emitted from GaN-based semiconductor laser element 300 is introduced into optical fiber 100. This optical fiber is branched into two in the middle, and the branched optical fibers do not cause any optical interaction with each other and are arranged along planes orthogonal to each other. Further, an optical film 104 for reflecting light is formed on each end face of the two optical fibers after branching, in order to prevent the guided light from being emitted therefrom and causing loss.
[0037]
As shown in FIG. 9B, the optical fiber 900 used in the fifth embodiment includes a core 200 and a clad 202 that guide light, but is different from the other embodiments. There is no light diffusion structure that includes a fine TiO ₂ particle. Instead, as shown in FIG. 9 (a), a region in which light is to be radiated from the optical fiber to the outside has a curvature larger than a predetermined size. As described above, the reason that light is emitted by giving the optical fiber a curvature equal to or larger than a predetermined value is that the angle at which light propagating in the core is incident on the interface of the cladding changes by bending the optical fiber. (See, for example, Optical Book Publishing, Yonezu, Optical Communication Device Engineering, 5th Edition).
[0038]
As shown in FIG. 10, in the fifth embodiment, an optical reflection film 1000 of, for example, aluminum is provided on a region other than the region where the laser light from the semiconductor laser element 300 is incident on the end face of the optical fiber 900. Thereby, the loss of the return light reflected by the reflection film 104 (see FIG. 8) provided on the other end surface side of the optical fiber 900 radiated from the optical coupling portion between the laser element 300 and the optical fiber 900 is reduced. be able to.
[0039]
By providing a plurality of optical fibers as in the fifth embodiment (see FIG. 8), the light distribution characteristics of each optical fiber can be easily controlled, and thus the controllability of the light distribution characteristics of the entire lighting device. Can be further improved. Further, according to the configuration of the fifth embodiment, it is possible to control the light distribution characteristics of the lighting device using an optical fiber that does not include a light diffusion structure including TiO ₂ particles.
[0040]
(Embodiment 6)
In FIG. 11, a lighting device according to Embodiment 6 of the present invention is schematically illustrated. FIG. 11 shows a state in which a part of the lighting device has been cut away. A feature of the sixth embodiment as compared with the first embodiment is that GaN-based semiconductor laser elements 300 are provided on both end faces of the optical fiber 100. With such a configuration, a lighting device having good light distribution characteristics can be realized.
[0041]
Further, in the sixth embodiment, since the semiconductor laser elements 300 are arranged on both end faces of the optical fiber 100, a high-output lighting device can be obtained. Also in the sixth embodiment, similarly to FIG. 10, it is preferable that a high-reflection film is provided on the end face of the optical fiber 100 in a region other than the region where the laser beam from the semiconductor laser element 300 is incident.
[0042]
(Embodiment 7)
12, a lighting system according to Embodiment 7 of the present invention is illustrated in a schematic block diagram. This lighting system includes an AC / DC conversion circuit 1203 for converting 100 V AC power 1204 from a commercial power supply into DC power. The DC power from the AC / DC conversion circuit 1203 is supplied to a drive circuit 1202 including a step-down circuit that converts the DC power into a voltage / current capable of driving the light emitting element. Driving power from the driving circuit 1202 is supplied to the light emitting element in the point lighting device 1200 via the socket 1201. Any of the lighting devices in the above-described first to sixth embodiments can be used as the point-like lighting device 1200, and thus the lighting device system according to the seventh embodiment can be configured.
[0043]
Here, as a method for driving the light emitting element, it is preferable to drive the light emitting element with a pulse current. This is because, when the light-emitting element is driven with a pulse current, the influence of heat generation in the light-emitting element can be reduced as compared with the case where the light-emitting element is driven with a DC current, so that a lighting system with high light output can be obtained.
[0044]
(Embodiment 8)
FIG. 13 is similar to FIG. 12, but illustrates a lighting system according to Embodiment 8 of the present invention. FIG. 13A schematically shows a transparent conductive pattern 1300 formed on the outer peripheral surface of the protective spherical shell 101 in the lighting system shown in the block diagram of FIG. 13B.
[0045]
That is, in the illumination system according to the eighth embodiment, red (Y ₂ O ₂ S: Eu ³⁺ ), green (ZnS: Cu, Al), and blue ((Sr, Ca, Ba, Mg) ₁₀ (PO ₄ ) _6. A transparent conductive film pattern 1300 made of, for example, tin oxide or ITO (indium tin oxide) is formed on the outer peripheral surface of the protective spherical shell 101 made of an acrylic resin in which a phosphor made of Eu ²⁺ ) is dispersed. Therefore, when the acrylic resin shell 101 is damaged by an external impact, the transparent conductive film pattern 1300 also breaks at the same time.
[0046]
A detection circuit connected to the transparent conductive film pattern 1300 is included in the drive circuit 1202 so that the breakage of the pattern can be detected. This detection circuit can monitor, for example, a weak current flowing through the transparent conductive film pattern 1300, and detect breakage of the protective spherical shell 101 by interruption of the current. When the detection circuit detects the breakage of the protective spherical shell 101, the drive circuit 1202 stops supplying power to be applied to the light emitting element.
[0047]
That is, in the illumination system of the eighth embodiment, as in the case where a semiconductor laser element is used as a light emitting element, light having high coherence, which is a problem from the viewpoint of eye safety, is directly emitted to space. Can be prevented. When the protective spherical shell 101 is broken, the supply of power to the light emitting element may be completely stopped, but the amount of radiation from the light emitting element may be reduced to a level that does not pose a safety problem to the eyes. Alternatively, the driving power may be controlled.
[0048]
【The invention's effect】
As described above, according to the present invention, it is possible to provide a lighting device that can easily control light distribution characteristics while using a semiconductor light emitting element and a phosphor.
[Brief description of the drawings]
FIG. 1 is a schematic diagram showing a state where a part of a lighting device according to a first embodiment of the present invention has been cut away.
FIG. 2A is a schematic perspective view showing a part of the optical fiber according to the first embodiment, and FIG. 2B is a sectional view thereof.
FIG. 3 is a schematic diagram showing a state where a part of a lighting device according to a second embodiment of the present invention has been cut away.
FIG. 4 is a schematic diagram illustrating a radiation light intensity distribution in the illumination device according to the second embodiment.
FIG. 5 is a schematic diagram showing a state in which a part of a lighting device according to a third embodiment of the present invention has been cut away.
FIG. 6 is a schematic cross-sectional view showing an example of an optical fiber structure used for a lighting device according to Embodiment 4 of the present invention.
FIG. 7 is a schematic sectional view showing another example of the optical fiber structure used for the lighting device according to the fourth embodiment.
FIG. 8 is a schematic diagram showing a state where a part of a lighting device according to a fifth embodiment of the present invention has been cut away.
FIG. 9A is a schematic perspective view showing an optical fiber according to a fifth embodiment, and FIG. 9B is a schematic sectional view showing the structure of the optical fiber.
FIG. 10A is a schematic perspective view showing a coupling portion between an optical fiber and a light emitting element in Embodiment 5, and FIG. 10B is an end view of the optical fiber.
FIG. 11 is a schematic diagram showing a state where a part of a lighting device according to a sixth embodiment of the present invention has been cut away.
FIG. 12 is a schematic block diagram showing a lighting system according to Embodiment 7 of the present invention.
13A is a top view of a protective spherical shell included in a lighting system according to Embodiment 7 of the present invention, and FIG. 13B is a block diagram of the lighting system.
[Explanation of symbols]
Reference Signs List 100 optical fiber, 101 acrylic resin, 102 GaN-based light emitting diode element, 103 wiring, 104 optical reflection film, 105 terminal, 106 resin, 200 core, 201 light diffusion structure, 202 clad, 300 GaN-based semiconductor laser element, 400, 401 , 402 light intensity distribution, 900 optical fiber, 1000 optical reflection film, 1200 illumination device, 1201 socket, 1202 drive circuit, 1203 AC / DC conversion circuit, 1204 AC power, 1300 transparent conductive film pattern.

Claims (13)

A light emitting element;
A fiber light guide that guides light introduced from the light emitting element and emits light from at least a part thereof,
A phosphor that absorbs light emitted from the light guide and emits fluorescence of another wavelength,
A light-transmitting protective container containing the light emitting element and the fibrous light guide,
A lighting device comprising an electrical structure for supplying power to the light emitting element. The lighting device according to claim 1, wherein at least a part of the light emitting region of the fibrous light guide has any one of a spiral shape, a parabolic shape, and a linear shape. The lighting device according to claim 1, wherein a phosphor is dispersed in a constituent material of the translucent protective container. 4. A light-diffusing structure which partially scatters light propagating through the light guide inside the light emission region of the fiber light guide is provided. Lighting equipment. The lighting device according to claim 4, wherein the fibrous light guide includes a core and a clad, and the light diffusing structure is provided in at least a part of the core. The lighting device according to claim 4, wherein the fibrous light guide includes a core and a clad, and the light diffusion structure is provided in at least one region where evanescent light exists in the clad. The fiber-shaped light guide includes a core and a clad, and a light emitting region of the light guide has a shape having a curvature that causes a part of light propagating in the core to be emitted. The lighting device according to any one of 1 to 3. The lighting device according to any one of claims 1 to 7, comprising a plurality of the fiber light guides. An optical film that reflects light propagating through the fibrous light guide is provided on a region other than a region where light from the light emitting element is incident on an end surface of the fibrous light guide. The lighting device according to claim 1. The lighting device according to any one of claims 1 to 9, wherein the light emitting elements are arranged on each of both end faces of the fibrous light guide. The lighting device according to any one of claims 1 to 10, wherein the light-emitting element comprises one of a semiconductor laser element and a light-emitting diode element. A lighting system including the lighting device according to any one of claims 1 to 11, wherein a driving circuit that supplies driving power is connected to the electric structure that supplies power to the light-emitting element. And lighting system. A conductive film is formed on at least a part of the surface of the translucent protective container, and further includes a control circuit that detects breakage of the conductive film and controls power supplied to the light emitting element. 13. The lighting system according to claim 12, characterized in that:

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