JP2015008155A - Lighting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lighting device, which reduces coherence of a laser beam radiated from a laser radiation device thereby securing safety of user's eyes, at low costs.SOLUTION: In a lighting device 1, a phosphor 3 is excited by a laser beam radiated from a laser radiation device 2 to obtain visible light and the visible light is used as illumination light. In the lighting device 1, the phosphor 3 is disposed at a position separated from the laser radiation device 2 and a light scattering material 4 is provided on a surface of the phosphor 3. The laser beam excites the phosphor 3 after penetrating through the light scattering material 4. The visible light emitted from the phosphor 3 penetrates through the light scattering material 4 and then is radiated to the exterior.

Description

  The present invention relates to an illumination apparatus that obtains visible light by exciting a phosphor with laser light emitted from a laser irradiation apparatus and uses the visible light as illumination light.

  Conventionally, regarding a communication apparatus that transmits and receives signals using laser light, safety measures have been proposed to prevent the risk of eye damage caused by light with high coherence emitted outside the transmitter.

  For example, in the infrared communication module described in Patent Document 1, in a light source device used for a transmission device of an infrared communication module, a liquid containing a dynamic light scattering system or a swollen gel is included in an optical path of emitted light of a semiconductor laser element. By placing (region containing light scattering system), light with high coherence is generated by dynamic light multiple scattering (Brownian motion) when light emitted from the semiconductor laser element passes through a region containing dynamic light scattering system. Is converted into incoherent light that does not damage humans.

  Alternatively, in the optical transmission device described in Patent Document 2, the light emitted from the semiconductor laser element is disposed by arranging a light scattering member including light scattering particles that scatter the laser light in the optical path of the emitted light of the semiconductor laser element. Is scattered when passing through the light scattering member, and the high coherence light is converted into incoherent light that does not damage humans.

  There has also been proposed an illuminating device that excites a phosphor with laser light emitted from a laser irradiating device to obtain visible light, converts the visible light into parallel rays by a reflecting mirror, and uses it as illumination light (Patent Literature). 3). Even in such a lighting device, there is a risk that light with high coherence leaks to the outside, and there is a danger to eyes. In Patent Document 3, as a countermeasure when laser light that does not completely absorb the phosphor is transmitted, a sub-reflecting mirror is installed in front of the phosphor, and the laser light transmitted through the phosphor is transmitted by the sub-reflecting mirror. A configuration is shown in which laser light is completely absorbed by being reflected and incident again on a phosphor.

JP 2003-258353 A JP 2006-352105 A JP 2003-295319 A

  In an illumination device that excites a phosphor with laser light emitted from a laser irradiation device to obtain visible light and uses the visible light as illumination light, laser light with high coherence used as excitation light for the phosphor is If one leak occurs, the danger to human eyes is considered high. The reasons for this are (1) change / deformation of parts over time, alignment of optical elements of the laser irradiation device due to external pressure and impact, etc. (2) change / deformation of parts over time, external pressure It is conceivable that the position of the phosphor shifts due to impact or impact, and (3) a laser beam that is transmitted without being completely absorbed by the phosphor is generated.

  Since Patent Documents 1 and 2 relate to a communication device, a region including a dynamic light scattering system and a light scattering member may be arranged in contact with or integrated with a semiconductor laser element that is a light source. However, in the illuminating device, since the phosphor is excited by irradiating the phosphor with the laser light transmitted from the semiconductor laser element, the positional relationship with the phosphor must be considered. In this regard, such knowledge cannot be obtained from Patent Documents 1 and 2.

  Further, in the configuration using the sub-reflecting mirror described in Patent Document 3, the laser light transmitted through the phosphor is reflected by the sub-reflecting mirror so as to be incident on the phosphor again in order to cope with the above (3). However, the cases (1) and (2) above are not considered.

    The present invention has been made in view of the above problems, and an object of the present invention is to provide a low-cost lighting device that can ensure eye safety by reducing the coherence of laser light emitted from a laser irradiation device. And

  In order to achieve the above object, the present invention provides an illumination device that excites a phosphor with laser light emitted from a laser irradiation device to obtain visible light, and uses the visible light as illumination light. A light scattering material is disposed on the optical axis and in the periphery thereof.

  According to this arrangement of the light scattering material, the laser light is transmitted through the light scattering material, so that the light is scattered in a random direction and the coherence of the laser light is reduced, so that the light with high coherence leaks to the outside. Is prevented. In addition, the light scattering material is disposed on and around the optical axis of the laser light, and even when the optical axis of the laser light and the position of the phosphor are displaced, the laser light reliably transmits the light scattering material. Safety is improved.

  Moreover, the present invention is characterized in that, in the illumination device configured as described above, the laser light passes through the light scattering material after exciting the phosphor. According to this, after the coherence is reduced by exciting the phosphor, the laser light is scattered in a random direction by passing through the light scattering material, and the coherence is further reduced. Leakage is prevented.

  Moreover, the present invention is characterized in that, in the illumination device configured as described above, the laser light excites the phosphor after passing through the light scattering material. According to this, after the laser light is scattered in a random direction through the light scattering material and the coherence is reduced, the phosphor is excited to further reduce the coherence, so that the light with high coherence leaks to the outside. Is prevented.

  Moreover, the present invention is characterized in that, in the illumination device having the above-described configuration, the light scattering material and the phosphor are arranged apart from each other. According to this configuration, the laser light passes through the light scattering material and is emitted to the space before exciting the phosphor.

  Moreover, the present invention is characterized in that, in the illumination device having the above-described configuration, the light scattering material and the phosphor are disposed in close contact with each other. According to this configuration, the laser light passes through the light scattering material and excites the phosphor without being released into space.

  Moreover, the present invention is characterized in that, in the illumination device configured as described above, irregularities having a size smaller than the wavelength of the laser beam are formed on the surface of the light scattering material. According to this, the laser beam reflected on the surface of the light scattering material can be suppressed.

  According to the present invention, in the lighting device having the above-described configuration, the phosphor is disposed on a metal plate. According to this, the heat generation of the phosphor can be actively radiated using the metal plate.

  According to the present invention, in the illumination device configured as described above, the laser irradiation device includes a plurality of semiconductor laser elements that oscillate laser light and a laser beam that condenses the laser light oscillated from each semiconductor laser element on a phosphor. And a light means. According to this structure, the brightness | luminance of a laser beam becomes high and the illumination intensity of an illuminating device can be made high.

  Further, the present invention provides the illumination device having the above configuration, wherein the laser irradiation device includes a light source that oscillates laser light, and a light guide unit that guides the laser light from the light source to the phosphor, The light scattering material is provided in close contact with the exit end of the light guide means.

  According to this configuration, since the light guide means and the light scattering material are integrated, the laser light emitted from the light guide means always passes through the light scattering material even if the position of the phosphor is displaced. For this reason, it is possible to reliably prevent the laser light emitted from the light source from leaking outside while maintaining high coherence.

  According to the present invention, in the illumination device having the above configuration, a phosphor is provided in close contact with the outside of the light scattering material.

  According to this configuration, since the light guiding means, the light scattering material, and the phosphor are integrated, even if the position of the phosphor is displaced, the light is guided so that the optical axis of the laser light follows the position displacement of the phosphor. The means and the light scattering material are also displaced, and the laser light emitted from the light guiding means always passes through the light scattering material and excites the phosphor. For this reason, the laser beam oscillated from the light source can be more reliably prevented from leaking outside while maintaining high coherence.

  Moreover, the present invention is characterized in that, in the illumination device configured as described above, the light scattering material is glass or resin in which light scattering particles are dispersed. According to this, the laser light emitted from the laser irradiation device is refracted and scattered due to the difference in refractive index between the glass or resin as the dispersion medium and the light scattering particles as the dispersoid, and the phase is randomized and emitted to the outside. This reduces coherence.

  Moreover, the present invention is characterized in that, in the illumination device configured as described above, the light scattering material includes a fluid in which light scattering particles are dispersed, and a transparent container that houses the fluid. According to this configuration, since the light scattering particles in the fluid can be temporally shaken using the Brownian motion, it is effective for reducing the coherence of the laser light with dynamic fluctuation.

  Moreover, the present invention is characterized in that, in the illumination device configured as described above, the transparent container is in close contact with the phosphor. According to this configuration, heat released as thermal energy from the excited phosphor is transmitted to the fluid via the transparent container, and thus the Brownian motion of the light scattering particles in the fluid can be promoted.

  Moreover, the present invention is characterized in that in the illumination device having the above-described configuration, the fluid circulation path and a pump provided in the middle of the circulation path are provided. According to this configuration, the fluid circulating in the circulation path fluctuates the local refractive index with time and disturbs the phase of the laser beam that passes through the light scattering material, thereby reducing the coherence of the laser beam. It is effective. Further, since the transparent container is in close contact with the phosphor, heat generated in the phosphor can be transported through the circulating fluid, and the cooling effect of the phosphor can be obtained at the same time.

  According to the present invention, the laser light is transmitted through the light scattering material, so that the light is scattered in random directions, the coherence of the laser light is reduced, and the light with high coherence is prevented from leaking to the outside. In addition, the light scattering material is disposed on the optical axis of the laser light and in the periphery thereof, so that even when the optical axis of the laser light or the position of the phosphor is displaced, the laser light reliably transmits the light scattering material. Accordingly, it is possible to provide a lighting device that can ensure eye safety at a low cost.

1 is a side sectional view schematically showing the structure of a lighting device according to a first embodiment of the present invention. Sectional drawing which showed schematically the structure of the illuminating device by the 2nd Embodiment of this invention. Side sectional view which shows schematic structure of the illuminating device by the 3rd Embodiment of this invention. The perspective view which shows the light-scattering material used for the illuminating device by 3rd Embodiment. Side sectional view which shows schematic structure of the illuminating device by the 4th Embodiment of this invention. The perspective view which shows the light-scattering material used for the illuminating device by 4th Embodiment. Side sectional view which shows schematic structure of the illuminating device by the 5th Embodiment of this invention. Enlarged view of the part (P part) surrounded by the broken line in FIG. Xx sectional view of FIG. Side sectional view which shows schematic structure of the illuminating device by the 6th Embodiment of this invention. Enlarged view of the part (Q part) surrounded by the broken line in FIG. Yy sectional view of FIG. Side sectional view which shows schematic structure of the illuminating device by the 7th Embodiment of this invention. Side sectional view which shows the fluorescent substance unit with which the illuminating device of 7th Embodiment is equipped. FIG. 2B is a side sectional view of the phosphor unit, and is a diagram for explaining the action of the light scattering material on the light that excites the phosphor, and the figure explaining the action of the light scattering material on the light emitted from the phosphor. (B) It is a sectional side view of the phosphor unit, and is a diagram for explaining the effect of the metal plate and the light scattering material on the heat generated from the phosphor Side sectional view which shows schematic structure of the illuminating device by the 8th Embodiment of this invention.

  Embodiments of the present invention will be described below with reference to the drawings.

<First Embodiment>
A first embodiment of the present invention will be described with reference to FIG. FIG. 1 is a side sectional view showing a schematic configuration of a lighting apparatus according to the first embodiment.

  As shown in FIG. 1, an illuminating device 1 according to the present invention includes a laser irradiation device 2, a phosphor 3 irradiated with laser light from the laser irradiation device 2, and an optical axis L of the laser light and its peripheral portion. It has the light-scattering material 4 arrange | positioned. The illuminating device 1 excites the phosphor 3 with laser light to convert it into visible light (for example, white light), and uses the visible light as illumination light. The lighting device 1 is used, for example, for a vehicle headlamp.

  The reflecting mirror 5 has a concave portion 5a that reflects the visible light converted by the phosphor 3 forward (to the right in FIG. 1), and is a metal parabolic mirror, for example. A plurality of (three in the present embodiment) through holes 5b are provided in the apex peripheral region of the reflecting mirror 5, and the phosphor 3 in the recess 5a is irradiated from the outside of the reflecting mirror 5 through the through holes 5b. can do. As the reflecting mirror 5, it is also possible to use a resin main body coated with a thin film of a highly reflective metal (for example, silver or aluminum). The coating does not need to be applied to the entire surface of the main body, and may be applied to at least the surface (reflection surface) that forms the recess 5a.

  The laser irradiation apparatus 2 includes a plurality of semiconductor laser elements 2a (three in the present embodiment) that oscillate laser light and laser light that is provided corresponding to each semiconductor laser element 2a and oscillated from the semiconductor laser element 2a. And a plurality of collimator lenses 2b that are parallel rays. Note that the collimator lens 2b is not necessarily required when a good parallel beam is directly oscillated from the semiconductor laser element 2a.

  Here, in the present application, the “optical axis” of the laser light does not mean the locus of the laser light actually emitted, but means a line obtained by extending the locus of the laser light emitted from the laser irradiation apparatus 2. . The “collimator” is an optical element used for manufacturing and adjusting an optical device, and produces a parallel light beam. In addition, “phosphor” means a mixture of fluorescent material particles mixed with glass resin or the like, or a mixture of fluorescent material particles mixed with a binder, or a fluorescent material particle sintered or pressed. It means a product obtained by processing particles of a fluorescent material into a bulk form by some method, such as a product hardened by molding or the like, or a product dispersed in a bulk.

  In the present embodiment, for example, three semiconductor laser elements 2a (total light output 3W) that oscillate laser light having a wavelength of 405 nm (blue violet) with a light output 1W per unit are used, and laser light is transmitted through the collimator lens 2b. Parallel rays are used so that three parallel rays intersect on the rear surface of the phosphor 3. In this way, the phosphor 3 can be excited by intensively irradiating the phosphor 3 with high-intensity laser light.

As the fluorescent material, for example, a composite material of Ce ³⁺ activated α-SiAlON and CaAlSiN ₃ : Eu ²⁺ can be used. The outer shape of the phosphor 3 is ideally symmetrical about the central axis, and a cylindrical shape, a spindle shape, a prism shape, or the like can be adopted. When this phosphor 3 is excited by a 405 nm blue-violet laser beam, the former material emits blue-green light and the latter material emits red light, and they are mixed to obtain white fluorescence. The phosphor 3 is fixed at a focal position in the concave portion 5 a of the reflecting mirror 5 by a fixture (not shown), and the fluorescence from the phosphor 3 can be projected forward by the reflecting mirror 5.

  A cover 6 made of a transparent resin that covers the front end surface of the reflecting mirror 5 is attached to the reflecting mirror 5 by being fitted. The cover 6 has a function of allowing dust or the like to enter the reflecting mirror 5. The shape of the cover 6 is preferably a disk shape corresponding to the circumference of the front end face of the reflecting mirror 5, but is not limited to this, and any shape can be adopted.

  The light scattering material 4 is a constituent element characteristic of the present invention, and has a function of scattering light in a random direction and reducing the coherence of laser light.

  The light scattering material 4 is bonded to the rear surface of the cover 6 so as to be positioned in front of the phosphor 3. According to the arrangement of the light scattering material 4, the laser light excites the phosphor 3 to reduce the coherence, and then is scattered in a random direction by passing through the light scattering material 4, thereby further reducing the coherence. , Light with high coherence is prevented from leaking to the outside. A known adhesive that is transparent when solidified can be used. The light scattering material 4 may be adhered to the front surface of the cover 6. Since the cover 6 also serves to hold the light scattering material 4, a part for holding the light scattering material 4 is unnecessary. Therefore, the holding part of the light scattering material 4 can create an excessive shadow in the concave portion 5a of the reflecting mirror 5, thereby preventing a disadvantage that hinders illumination.

  Further, the light scattering material 4 is arranged such that an effective portion exists on the optical axis L of the laser light and the peripheral portion thereof. According to the arrangement of the light scattering material 4, even when the optical axis L of the laser light or the position of the phosphor 3 is shifted, it is possible to prevent the laser light from leaking outside while maintaining high coherence. . Therefore, it is possible to provide the lighting device 1 that can ensure eye safety at a low cost.

  The outer shape of the light scattering material 4 is preferably symmetric around the central axis so that it can be dealt with in any direction in the vertical plane where the optical axis L of the laser light or the phosphor 3 is displaced. Shape, square plate shape, etc. can be adopted. The area of the cross section perpendicular to the central axis of the light scattering material 4 is the same as the area of the cross section perpendicular to the central axis of the phosphor 3 so that the phosphor 3 can be dealt with even if the phosphor 3 is displaced from the optical axis L of the laser beam. It is preferable that the size of the light-emitting material 4 is set so that the phosphor 3 is hidden inside the light scattering material 4 when the lighting device 1 is viewed from the front.

  In the present embodiment, the light scattering material 4 is made of glass in which light scattering particles are uniformly dispersed at a high concentration. As the light scattering particles, silicon oxide particles (particle size: 1 μm) can be suitably used. The light-scattering material 4 is produced by dispersing such light-scattering particles in a molten glass base material and curing it in a desired shape with a mold. The weight ratio of the light scattering particles and the glass base material is, for example, 30%. According to this light scattering material, the laser light emitted from the laser irradiation device 2 is refracted and scattered due to the difference in refractive index between glass and silicon oxide, and the coherence is reduced by the phase being random and coming out. Is done.

  As shown in FIG. 1, a filter 7 that absorbs 405 nm laser light and transmits white light may be provided on the outer surface of the cover 6. The filter 7 guarantees a reduction in the coherence of the laser light by the light scattering material 4. Even when the light scattering material 4 is not present, 99% of the laser light is absorbed by the filter 7, but 1% is unavoidably leaked to the outside. For example, if the laser output is 3 W, 30 mW leaks, and it is dangerous to leak while maintaining high coherence. In the present embodiment, since the light scattering material 4 is disposed behind the filter 7, the laser light is scattered when passing through the light scattering material 4 and passes through the filter 7 after coherence is sufficiently reduced. It will be. In other words, laser light leakage can be prevented 100% by double safety measures.

<Second Embodiment>
Next, a second embodiment of the present invention will be described with reference to FIG. FIG. 2 is a side sectional view showing a schematic configuration of the illumination device according to the second embodiment. In the illuminating device according to the present embodiment, the same parts as those of the illuminating device according to the first embodiment shown in FIG. 1 are denoted by the same reference numerals, and detailed description thereof is omitted.

  The illuminating device 1 according to the present embodiment is provided with a lens 8 on the inner periphery of the front end of the reflecting mirror 5 instead of the cover 6 in the illuminating device 1 of the first embodiment. In addition to the function of controlling the solid angle when projecting fluorescence, the lens 8 also has a function as a cover for preventing dust and the like from entering the reflecting mirror 5. Note that although a convex lens is shown in FIG. 2 as an example of the lens 8, it goes without saying that a concave lens or other lens can be used according to the application or purpose of the lighting device.

  As in the first embodiment, the laser irradiation apparatus 2 includes a plurality of semiconductor laser elements 2a (five in this embodiment) that oscillate laser light, and semiconductor lasers provided corresponding to the semiconductor laser elements 2a. And a plurality of collimator lenses 2b that use laser light oscillated from the element 2a as parallel rays. Note that the collimator lens 2b is not necessarily required when a good parallel beam is directly oscillated from the semiconductor laser element 2a.

  In the present embodiment, for example, five semiconductor laser elements 2a (total light output 2.5W) that oscillate laser light having a wavelength of 450 nm (blue) with an optical output of 0.5W per unit are used and passed through the collimator lens 2b. The laser light is converted into parallel rays so that the three parallel rays intersect on the rear surface of the phosphor 3. In this way, the phosphor 3 can be excited by intensively irradiating the phosphor 3 with high-intensity laser light.

  A plurality of (in the present embodiment, five) through holes 5b are provided in the apex peripheral region of the reflecting mirror 5, and the phosphor 3 in the recess 5a is irradiated from the outside of the reflecting mirror 5 through the through holes 5b. can do.

For example, (Y, Gd) ₃ Al ₅ O ₁₂ : Ce can be used as the material of the phosphor 3. The outer shape of the phosphor 3 is ideally symmetrical about the central axis, and a cylindrical shape, a spindle shape, a prism shape, or the like can be adopted. When this phosphor 3 is excited with a blue laser beam of 450 nm, it emits yellow light and is mixed with surplus blue to obtain white fluorescence. The phosphor 3 is fixed at a focal position in the concave portion 5 a of the reflecting mirror 5 by a fixture (not shown), and the fluorescence from the phosphor 3 can be projected forward by the reflecting mirror 5.

  The light scattering material 4 is bonded to the rear surface of the lens 8 so as to be positioned on the optical axis L of the laser beam and its peripheral portion and in front of the phosphor 3. As the adhesive, a known adhesive which is transparent when solidified can be used. The light scattering material 4 may be fixed to the front surface of the lens 8. Since the lens 8 also serves to hold the light scattering material 4, a component for holding the light scattering material 4 is unnecessary. Thereby, the holding part of the light-scattering material 4 makes an excessive shadow in the recessed part 5a of the reflective mirror 5, and the demerit which becomes an obstacle to illumination can be prevented.

  In the present embodiment, a resin in which light scattering particles are uniformly dispersed at a high concentration is used as the light scattering material 4. Specifically, a silicone resin in which titanium oxide particles (particle size 2 μm) are dispersed can be suitably used. The light-scattering material 4 is produced by dispersing such light-scattering particles in a molten glass base material and curing it in a desired shape with a mold. The weight ratio of the light scattering particles and the glass base material is, for example, 30%. According to this light scattering material, the laser light emitted from the laser irradiation device 2 is refracted and scattered due to the difference in refractive index between the glass and the titanium oxide particles, and the coherence is caused by the phase being random and coming out. Reduced.

  According to the light scattering material 4 of the present embodiment, the laser light emitted from the laser irradiation device 2 is refracted and scattered due to the difference in refractive index between the silicone resin and the titanium oxide particles, and the phase is randomized and emitted to the outside. This reduces coherence.

  Note that a filter having a function of absorbing laser light may be provided on the front surface of the lens 8 as in the first embodiment.

<Third Embodiment>
Next, a third embodiment of the present invention will be described with reference to FIGS. FIG. 3 is a side sectional view showing a schematic configuration of the illumination device according to the third embodiment, and FIG. 4 is a perspective view showing a light scattering material used in the illumination device. In the illuminating device according to the present embodiment, the same parts as those of the illuminating device according to the first embodiment shown in FIG. 1 are denoted by the same reference numerals, and detailed description thereof is omitted.

  In the present embodiment, the laser irradiation apparatus 2 includes a plurality of semiconductor laser elements 2a (three in the present embodiment) that oscillate laser light, and the semiconductor laser elements 2a provided corresponding to the semiconductor laser elements 2a. A plurality of collimator lenses 2b that make the oscillated laser beam parallel rays; a condenser lens 2c that is provided corresponding to each semiconductor laser element 2a and each collimator lens 2b and collects the laser beams that are made parallel rays; It is the structure which has. Note that the collimator lens 2b is not necessarily required when a good parallel beam is directly oscillated from the semiconductor laser element 2a.

  In the laser irradiation apparatus 2 of the present embodiment, since the laser light is condensed by the condenser lens 2c, after passing through the condenser lens 2c, it is no longer a parallel light beam but a light beam that converges at the position of the phosphor. . Unlike the previous embodiments, the laser light applied to the phosphor is not parallel light, and the laser light spreads if the laser light passes through the phosphor. In this application, even if the laser light is not parallel light, the range in which coherent light spreads is expressed by the phrase “optical axis” in a broad sense.

  A through hole 5b is provided in the peripheral region including the apex of the reflecting mirror 5, and the phosphor 3 in the recess 5a can be irradiated from the outside of the reflecting mirror 5 through the through hole 5b.

  In the present embodiment, as the light scattering material 4, as shown in FIGS. 3 and 4, a fluid 4a in which light scattering particles are dispersed and a transparent container 4b that houses the fluid 4a are used. Used. As the fluid 4a in which the light scattering particles are dispersed, for example, silicone oil containing silicon oxide particles at a high concentration can be suitably used. As the transparent container 4b, a transparent disk-shaped glass container can be suitably used.

  In the light scattering material 4, the transparent container 4 b is disposed in close contact with the front surface of the phosphor 3 so that the light scattering material 4 is located in a range W around the coherent light and its peripheral portion and in front of the phosphor 3. For the close contact between the transparent container 4b and the phosphor 3, it is preferable to use an adhesive so as not to create an extra shadow in the concave portion 5a of the reflecting mirror 5. As the adhesive, a known adhesive that is transparent when solidified can be used.

  According to the light scattering material 4 of the present embodiment, since the light scattering particles in the fluid 4a can be temporally shaken using Brownian motion, the laser that passes through the light scattering material 4 with dynamic fluctuations. It is effective in reducing the coherence of light. Since the transparent container 4b is in close contact with the phosphor 3, heat released as thermal energy from the excited phosphor 3 is transmitted to the fluid 4a via the transparent container 4b, and thus the light scattering particles in the fluid 4a. Can promote the Brownian movement.

  As in the first embodiment, a cover may be provided on the front end surface of the reflecting mirror 5, and a filter that absorbs laser light may be provided on the cover.

<Fourth Embodiment>
Next, a fourth embodiment of the present invention will be described with reference to FIGS. FIG. 5 is a side sectional view showing a schematic configuration of the illumination device according to the fourth embodiment, and FIG. 6 is a perspective view showing a light scattering material used in the illumination device. In the illuminating device according to the present embodiment, the same parts as those of the illuminating device according to the third embodiment shown in FIGS. 3 and 4 are denoted by the same reference numerals, and detailed description thereof is omitted.

  Similarly to the third embodiment, the laser irradiation apparatus 2 includes a plurality of semiconductor laser elements 2a (three in the present embodiment) that oscillate laser light, and a semiconductor laser provided corresponding to each semiconductor laser element 2a. A plurality of collimator lenses 2b that make the laser light oscillated from the element 2a parallel rays, and a condensing lens that is provided corresponding to each semiconductor laser element 2a and each collimator lens 2b and condenses the laser beams that are made parallel rays. 2c. Note that the collimator lens 2b is not necessarily required when a good parallel beam is directly oscillated from the semiconductor laser element 2a.

  In the laser irradiation apparatus 2 of the present embodiment, since the laser light is condensed by the condenser lens 2c, after passing through the condenser lens 2c, it is no longer a parallel light beam but a light beam that converges at the position of the phosphor. . Unlike the previous embodiments, the laser light applied to the phosphor is not parallel light, and the laser light spreads if the laser light passes through the phosphor. In this application, even if the laser light is not parallel light, the range in which coherent light spreads is expressed by the phrase “optical axis” in a broad sense.

  As in the third embodiment, the light scattering material 4 is composed of a fluid 4a in which light scattering particles are dispersed and a transparent container 4b in which the fluid 4a is accommodated, as shown in FIGS. Is used. As the fluid 4a in which the light scattering particles are dispersed, for example, silicone oil containing silicon oxide particles at a high concentration can be suitably used. As the transparent container 4b, a transparent disk-shaped glass container can be suitably used.

  In the light scattering material 4, the transparent container 4 b is disposed in close contact with the front surface of the phosphor 3 so as to be positioned in front of the phosphor 3 in the range W where the coherent light spreads and the periphery thereof. For the close contact between the transparent container 4b and the phosphor 3, it is preferable to use an adhesive so as not to create an extra shadow in the concave portion 5a of the reflecting mirror 5. As the adhesive, a known adhesive that is transparent when solidified can be used.

  In this Embodiment, as shown in FIG. 5, the circulation path of the fluid 4a is formed by connecting the pipe 9 which comprises a closed circuit to the upper end and lower end of the transparent container 4b. A pump 10 as a power source is provided in the middle of the circulation path 4a, and the fluid 4a is circulated in the circulation path by driving the pump 10.

  According to the light scattering material 4 of the present embodiment, the light scattering particles in the fluid 4 a have a local refractive index that fluctuates in time due to the flow of the fluid 4 a that circulates in the circulation path 9. Since the phase of the passing laser beam is disturbed, it is effective in reducing the coherence of the laser beam. Further, since the transparent container 4b is in close contact with the phosphor 3, heat generated in the phosphor 3 can be transported through the circulating silicone oil, and the cooling effect of the phosphor 3 can be obtained at the same time. Accordingly, it is possible to suppress the secular change of the phosphor 3 and extend the life.

  As in the first embodiment, a cover may be provided on the front end face of the reflecting mirror 5, and a filter that absorbs laser light may be provided on the cover.

<Fifth Embodiment>
Next, a fifth embodiment of the present invention will be described with reference to FIGS. FIG. 7 is a side sectional view showing a schematic configuration of the lighting apparatus according to the fifth embodiment, FIG. 8 is an enlarged view of a portion (P portion) surrounded by a broken line in FIG. 7, and FIG. 9 is an xx line in FIG. It is sectional drawing. In the illuminating device according to the present embodiment, the same parts as those of the illuminating device according to the first embodiment shown in FIGS. 1 and 2 are denoted by the same reference numerals, and detailed description thereof is omitted.

  The illumination apparatus 1 according to the present embodiment corresponds to a plurality of (three in the example of FIG. 7) semiconductor laser elements (light sources) 2a that oscillate laser light as the laser irradiation apparatus 2, and corresponding to each semiconductor laser element 2a. A plurality of collimator lenses 2b which are provided as parallel light beams that are provided and oscillated from the semiconductor laser element 2a, and light beams which are provided corresponding to the semiconductor laser elements 2a and the collimator lenses 2b and converted into parallel light beams are guided. And an optical fiber 2d that emits light. The optical fiber 2d is an example of a light guiding unit that guides the laser light oscillated from the semiconductor laser element 2a to the phosphor 3 and emits it, and the light guiding unit is not limited to the optical fiber.

  As the optical fiber 2d, as shown in FIGS. 8 and 9, a fiber having a known structure having a core 2e serving as a nucleus and a clad 2f covering the periphery of the core 2e can be used. In the configuration of this optical fiber 2d, when laser light enters from one end (incident end) of the core 2e, it propagates inside the core 2e while being reflected at the boundary between the core 2e and the clad 2f, and the other end (exit end) of the core 2e. It will be emitted from.

  As shown in FIG. 8, the light scattering material 4 is disposed in close contact with the emission end of the optical fiber 2d so as to be positioned behind the phosphor 3 (on the left side in FIG. 7). According to this configuration of the light scattering material, the laser light passes through the light scattering material 4 and is scattered in a random direction to reduce the coherence, and then excites the phosphor 3. Therefore, in the unlikely event that the alignment of the optical elements of the laser irradiation device is misaligned due to changes / deformations / external pressures / impacts, etc., due to aging, parts changes / deformations, aging / external pressure / impact Even when the position of the phosphor is shifted, the coherence of the excitation light from the semiconductor laser is low, and light with high coherence is prevented from leaking to the outside.

  For the close contact between the optical fiber 2d and the light scattering material 4, it is preferable to use a metal ferrule 12. In FIG. 8, for convenience of explanation, the three optical fibers 2d are shown as being aligned vertically at the exit end, but in actuality, as shown in FIG. It will be bundled most closely so that it looks like a bowl when viewed in cross section. In this way, by integrating the light scattering material 4 with the optical fiber 2d, the optical fiber 2d is fixed to a position where light can be reliably guided from the semiconductor laser element 2a to the phosphor 3, and the laser emitted from the optical fiber 2d. The light scattering material 4 can be simultaneously fixed at a position where light reliably passes through the light scattering material 4.

  The light scattering material 4 is disposed such that an effective portion exists on the optical axis L of the laser beam and the periphery thereof. In the present embodiment, the “optical axis” of the laser light is a line indicated by an extension of the central axis of the emission end of each optical fiber 2d, and is not necessarily the trajectory in which the emitted laser light actually travels. I have not done it.

  A concave sub-reflecting mirror 11 is fixed in the concave portion 5a of the reflecting mirror 5 at a front position of the phosphor 3 by a fixture (not shown). This sub-reflecting mirror 11 is a hemispherical mirror. As a result, the forward fluorescence from the phosphor 3 can be returned to the phosphor 3 again by the sub-reflecting mirror 11, so that the fluorescence emitted in the direction opposite to that of the reflecting mirror 5 can be reused. Become. The sub-reflecting mirror 11 is preferably small so as not to block the projection light from the reflecting mirror 5 as much as possible.

  In the present embodiment, the light scattering material 4 is spaced from the phosphor 3 held at the focal position in the recess 5a of the reflecting mirror 5, and the laser light emitted from the optical fiber 2d is light After passing through the scattering material 4 and being emitted into the space, the phosphor 3 is excited.

  As described in the above embodiment, the light scattering material 4 may be any glass or resin in which light scattering particles are dispersed, or a material containing a fluid in which light scattering particles are dispersed in a transparent container. You can choose to use.

  The light propagating through the optical fiber 2d basically maintains the same high coherence as the laser light emitted from the semiconductor laser element 2a, but it is possible to reduce the coherence by passing through the light scattering material 4. It becomes. Even if the coherence decreases, the wavelength of the laser beam does not change, and the decrease in luminance can be suppressed by adjusting the number of the laser semiconductor elements 2 a and the length of the light scattering material 4. By irradiating the phosphor 3 with laser light, sufficient fluorescence can be obtained.

  According to the illumination device according to the present embodiment, the laser light emitted from the semiconductor laser element 2a as the light source is guided to the phosphor 3 using the flexible optical fiber 2d as the light guide means. There is an advantage that the positional accuracy of the alignment of the optical elements is not required as compared with the case where the laser beam is condensed on the phosphor 3 using the condensing lens as in the fourth embodiment. Moreover, since the freedom degree of arrangement | positioning of the semiconductor laser element 2a becomes high on illumination device design, the use expansion of illumination devices, such as remote illumination, is achieved.

  As in the first embodiment, a cover may be provided on the front end face of the reflecting mirror 5, and a filter that absorbs laser light may be provided on the cover.

<Sixth Embodiment>
Next, a sixth embodiment of the present invention will be described with reference to FIGS. FIG. 10 is a side sectional view showing a schematic configuration of a lighting apparatus according to the sixth embodiment, FIG. 11 is an enlarged view of a portion (Q portion) surrounded by a broken line in FIG. 10, and FIG. 12 is a yy line in FIG. It is sectional drawing. In the illuminating device according to the present embodiment, the same parts as those of the illuminating device according to the fifth embodiment shown in FIGS. 7 to 9 are denoted by the same reference numerals, and detailed description thereof is omitted.

  In the laser illumination device 1 according to the present embodiment, as in the fifth embodiment, as the laser irradiation device 2, a plurality (three in the example of FIG. 7) of semiconductor laser elements (light sources) 2a that oscillate laser light and A plurality of collimator lenses 2b provided corresponding to the respective semiconductor laser elements 2a and using laser beams emitted from the semiconductor laser elements 2a as parallel rays, and provided corresponding to the respective semiconductor laser elements 2a and the respective collimator lenses 2b. And an optical fiber 2d that guides and emits the parallel laser beam. The optical fiber 2d is an example of a light guiding unit that guides the laser light oscillated from the semiconductor laser element 2a to the phosphor 3 and emits it, and the light guiding unit is not limited to the optical fiber.

  As shown in FIGS. 11 and 12, the phosphor 3 held at the focal position in the recess 5 a of the reflecting mirror 5 has a cavity 3 a corresponding to the outer shape of the light scattering material 4 at the center of the rear part. The axial length of the cavity 3 a is set longer than that of the light scattering material 4.

  As shown in FIGS. 10 and 11, the light scattering material 4 is disposed so as to be in close contact with the emission end of the optical fiber 2d. The optical fiber 2d and the light scattering material 4 are fixed by holding the light scattering material 4 so as to be in close contact with the emission end of the optical fiber 2d and inserting the optical fiber 2d into the cavity 3a of the phosphor 3 together with the optical fiber 2d. As shown in FIG. 11, the outer shape of the phosphor 3 that covers the light scattering material 4 is preferably a sphere that can emit fluorescence evenly in any direction around it, but is symmetrical about the central axis. However, for example, a cylindrical shape, a prismatic shape, or the like may be employed.

  In the present embodiment, although the positional relationship before and after the light scattering material 4 with respect to the phosphor 3 does not seem clear, the light scattering material 4 that reduces the coherence of the laser light before exciting the phosphor 3 is used. In terms of function, it can be seen that the light scattering material 4 is disposed behind the phosphor 3 as in the fifth embodiment.

  In the present embodiment, the light scattering material 4 is disposed in close contact with the phosphor 3 held at the focal position in the concave portion 5a of the reflecting mirror 5, and the laser light emitted from the optical fiber 2d is light. The phosphor 3 is excited without passing through the scattering material 4 and being released into space. Moreover, since the phosphor 3 covers a wide range from the peripheral surface to the front surface of the light scattering material 4, the phosphor 3 can be irradiated without leaving laser light.

  As described in the above embodiment, the light scattering material 4 is preferably a glass or resin in which light scattering particles are dispersed, or a material containing a fluid in which light scattering particles are dispersed in a transparent container. Can be used for

  According to the illumination device according to the present embodiment, the optical fiber 2d, the light scattering material 4, and the phosphor 3 are integrated, and even if the position of the phosphor 3 is shifted, the laser beam is displaced in the position shift of the phosphor 3. The optical fiber 2d and the light scattering material 4 are also displaced in the form that the optical axis L follows, and the laser light emitted from the optical fiber 2d always passes through the light scattering material 4 and excites the phosphor 3, so that the semiconductor laser element The laser light oscillated from 2a can be more reliably prevented from leaking outside while maintaining high coherence. Even if the phosphor 3 deteriorates or disappears due to a change / deformation of parts due to aging, external pressure or impact, etc., the laser light is surely received by the light scattering material 4 provided at the emission end of the optical fiber 2d. The coherence is reduced, and light with high coherence is prevented from leaking to the outside.

<Seventh Embodiment>
Next, a seventh embodiment of the present invention will be described with reference to FIGS. FIG. 13 is a side sectional view showing a schematic configuration of the illumination apparatus according to the seventh embodiment. FIG. 14 is a side sectional view showing a phosphor unit provided in the illumination device of the seventh embodiment. In the illuminating device according to the present embodiment, the same parts as those of the illuminating device according to the fifth embodiment shown in FIGS. 7 to 9 are denoted by the same reference numerals, and detailed description thereof is omitted.

  In the present embodiment, as shown in FIG. 13, a parabolic mirror having a deep recess 5 a is used as the reflecting mirror 5. The deep parabolic mirror of the recess 5a has a feature that the focal position approaches the apex. This feature leads to the merit that even if the phosphor 3 is arranged in the vicinity of the apex of the reflecting mirror 5, parallel rays can be extracted efficiently. In particular, when the phosphor 3 is arranged at the apex of the reflecting mirror 5, since the phosphor 3 can be held by the reflecting mirror 5 itself, a separate holding member is not required and an extra shadow is not formed in the recess 5a. Get better.

  Another feature is that the rise from the top of the reflecting surface is abrupt. This feature leads to the merit that the outer shape of the reflecting mirror 5 can be elongated. The slender reflecting mirror 5 is useful for making the incident angle of laser light incident from the outside of the side surface toward the apex acute because the inclination of the side surface portion is nearly parallel to the central axis Z. Thereby, in the said 1st-6th embodiment, the through-hole 5b which penetrates the reflective mirror 5 was provided in the back of the fluorescent substance 3 (FIG.1, FIG.2, FIG.3, FIG.5, FIG.7, In contrast to the case of FIG. 10), in the present embodiment, as shown in FIG. 13, the through hole 5 b can be provided in front of the phosphor 3.

  A circular mounting hole 5c is opened at the apex of the reflecting mirror 5 and its periphery, and a phosphor described later, which is configured by integrating the phosphor 3 and the light scattering material 4 on the metal plate 13 in the mounting hole 5c. Unit 14 is mounted as shown.

  In the illumination device 1 according to the present embodiment, the laser irradiation device 2 disposed outside the reflecting mirror 5 includes a plurality (for example, 10) of semiconductor laser elements (light sources) 2a that oscillate laser light, and each semiconductor laser. A plurality of collimator lenses 2b that are provided corresponding to the element 2a and that use laser light emitted from the semiconductor laser element 2a as parallel rays, and are provided corresponding to the semiconductor laser elements 2a and collimator lenses 2b as parallel rays. A plurality of optical fibers 2d that guide and emit the laser light, a condensing lens 2e that condenses the plurality of laser lights emitted from the plurality of optical fibers 2d to form parallel rays, and the condensed light And a reflecting plate 2f that reflects the light. Note that the collimator lens 2b is not necessarily required when a good parallel beam is directly oscillated from the semiconductor laser element 2a.

  The condenser lens 2e is arranged so as to be orthogonal to the optical axis L1 of the laser light emitted from the emission end of the bundled optical fiber 2d. The reflecting plate 2 f is located in front of the through hole 5 b of the reflecting mirror 5. The inclination of the reflecting plate 2f from the vertical axis (indicated by the symbol α in FIG. 13) indicates that the optical axis L2 of the reflected laser light passes through the through hole 5b of the reflecting mirror 5 and is directed near the apex of the reflecting mirror 5. Is set to such an angle.

  The phosphor 3 is fixed on a metal plate 13, and a light scattering material 4 is formed in layers so as to cover the surface of the phosphor 3. In this embodiment, a structure in which the phosphor 3 and the light scattering material 4 are integrally disposed on the metal plate 13 is referred to as a phosphor unit (denoted by reference numeral 14).

  Next, the configuration of the phosphor unit 14 will be specifically described with reference to FIG.

  As a material of the metal plate 13, a metal having good thermal conductivity such as copper or aluminum can be suitably used. The planar shape of the metal plate 13 can employ any shape such as a circle or a rectangle, and the thickness is not particularly limited. However, since the metal plate 13 has a function of transferring heat generated from the phosphor 3 to dissipate it in the air, it needs a certain area and thickness. Further, by improving the reflectance of the surface of the metal plate 13 on the side where the phosphor 3 is installed (for example, by applying a mirror finish), the fluorescence emitted from the phosphor 3 to the metal plate 13 is reflected and reflected again. It can be used and is preferable.

  As the material of the phosphor 3, a material in which the above-described phosphor powder is uniformly dispersed in a transparent resin can be suitably used. As the transparent resin, an ultraviolet (UV) curable adhesive can be suitably used. The weight ratio of the fluorescent material to the transparent resin is, for example, 30%. In the present embodiment, a fluorescent substance powder is mixed in an adhesive, applied onto the metal plate 13, and cured. The phosphor was, for example, 3 mmφ × 0.2 mm thick. In addition, although arbitrary shapes, such as a cylinder and a cone, can be employ | adopted for the external shape of the fluorescent substance 3, in this Embodiment, since it is necessary to fix the fluorescent substance 3 on the metal plate 13, it is a plane used as a fixed surface at least. A shape with is desirable.

  As the light scattering material 4, a glass base material in which titanium oxide particles having a particle diameter of 1 to 50 μm as light scattering particles are uniformly dispersed at a weight ratio of 30% can be suitably used. The light scattering material 4 is disposed in layers on the entire surface of the phosphor 3 (upper surface and side surface in the case of a cylindrical shape). The layer thickness of the light scattering material 4 is set to 0.5 mm, for example.

  In the present embodiment, as shown in FIG. 13, laser light is incident on the phosphor 3 from the outside of the light scattering material 4 formed in a layer form on the surface of the phosphor 3, and the phosphor 3 is excited. The emitted fluorescence is taken out from the surface of the light scattering material 4. Therefore, it is ideal that the surface of the light scattering material 4 is non-reflective with respect to laser light and fluorescence. For this reason, as shown in FIG. 14, minute irregularities 4 c for reducing surface reflection are formed on the entire surface of the light scattering material 4.

  About the size of the unevenness 4c, the distance between any two adjacent protrusions in the plane (distance between two adjacent recesses) (hereinafter referred to as "interval between protrusions" and indicated by the symbol p in FIG. 14) In addition, it is necessary to set both the height of the convex portion (depth of the concave portion) (indicated by symbol h in FIG. 14) to be smaller than the wavelengths of the laser light and the fluorescence. By forming a concavo-convex structure having a size smaller than such a wavelength on the surface of the light scattering material 4, between the inside and outside of the light scattering material on the surface of the light scattering material 4 (in this embodiment, glass and air, respectively). It is possible to make the change in the refractive index smooth, and almost no surface reflection occurs.

  In this embodiment, the unevenness interval (p) is about 100 nm, and the height (h) of the convex part is about 150 nm. On the other hand, the laser light has a spectrum having a strong single peak wavelength at 405 nm, and the fluorescence has a broad wavelength spectrum extending in the range of 420 nm to 800 nm. Therefore, the size example of the unevenness 4c is sufficiently smaller than the wavelengths of the laser beam and the fluorescence.

  The unevenness 4c may be periodic (the dimensions of p and h in FIG. 14 are uniform) or random (the dimensions of p and h in FIG. 14 are not uniform). However, since the interval between the concaves and convexes becomes very small, it is easier to realize a structure having the desired characteristics of being non-reflective with respect to laser light and fluorescence by making them periodically rather than randomly forming them.

  Various methods for producing such a phosphor unit 14 are conceivable. As an example, the following method can be employed. That is, a fluorescent substance powder is mixed in a UV curable adhesive, and is applied to the metal plate 13 in a desired shape (cylindrical in this embodiment). Then, the UV curable resin is cured by irradiation with ultraviolet rays. Thereby, a structure in which the phosphor 3 having a desired shape is fixed on the metal plate 13 can be easily made. Then, a glass powder having a low melting point and titanium oxide particles are placed on the exposed surface of the phosphor 3 and heated to 600 ° to melt the glass. When the glass flows and spreads over the entire surface, the heating is stopped. Solidify. Thereby, a structure in which the light scattering material 4 is formed in a layer on the surface of the phosphor 3 can be easily made.

  As shown in FIG. 13, the phosphor unit 14 configured as described above has a phosphor portion inserted into the mounting hole 5 c from the rear of the reflector 5, and the surface of the metal plate 13 is the central axis Z of the reflector 5. Is fixed to the reflecting mirror 5 in an arrangement substantially perpendicular to the reflecting mirror 5. The phosphor unit 14 may be fixed to the reflecting mirror 5 by using insertion or adhesion of the phosphor portion into the mounting hole 5c, or by fixing the metal plate portion to the outer surface portion of the reflecting mirror 5 with a screw or the like. It is also possible to fix using

  In the present embodiment, as in the fifth and sixth embodiments (see FIGS. 7 and 10), the laser light excites the phosphor 3 after passing through the light scattering material 4.

  Next, the operation of the phosphor unit 14 will be described with reference to FIGS. 15 and 16. FIG. 15A is a side cross-sectional view of the phosphor unit of the present embodiment, and shows the effect of the light scattering material on the light that excites the phosphor (hereinafter also referred to as “excitation light”). FIG. 15B is a side sectional view for explaining the effect of the light scattering material on the light emitted from the phosphor (hereinafter also referred to as “fluorescence”). FIG. 16 is a side cross-sectional view of the phosphor unit of the present embodiment, and is a diagram for explaining the effect of the light scattering material and the light scattering material on the heat generated from the phosphor.

  As indicated by an arrow A1 in FIG. 15A, the laser beam (in this embodiment, a blue-violet laser beam having a wavelength of 405 nm) is adjusted in a direction in which its optical axis strikes the approximate center of the upper surface of the phosphor 3. The Since the light scattering material 4 formed in layers is present on the surface of the phosphor 3, the laser light is not directly incident on the phosphor 3 but is incident on the inside from the surface of the light scattering material 4. Become. At this time, the surface of the light scattering material 4 is provided with unevenness 4c having a size smaller than the wavelength of the laser beam (that is, the dimensions of p and h in FIG. 14 are smaller than the wavelength of the laser beam). The laser light is hardly reflected on the surface of the light scattering material 4 (reflectance is less than 0.1%), and almost all enters the light scattering material 4.

  The laser light that has entered the light scattering material 4 is incident on the phosphor 3 after being scattered by the scattering particles in the light scattering material 4 as indicated by an arrow A2 in FIG. . At this time, since light scattering particles (titanium oxide particles) having a size larger than the wavelength are dispersed inside the light scattering material 4, the laser light that has entered the light scattering material 4 is subjected to multiple scattering. This reduces the coherence of the laser light. Although the scattered excitation light has reduced coherence, the wavelength of the original laser light is maintained. Therefore, the fluorescent material inside the phosphor 3 is excited by the excitation light incident on the phosphor 3.

  The phosphor 3 emits white fluorescence when excited by laser light. At this time, as shown in FIG. 15 (b), the white fluorescence is multiply scattered by the light scattering particles in the light scattering material 4 as in the case of the excitation light. The scattered fluorescence reaches the surface of the light scattering material 4 disposed on the upper surface and the side surface of the phosphor 3. Most of the fluorescence directed toward the bottom surface of the phosphor 3 is also reflected by the metal plate 13 and reaches the surface of the light scattering material 4. At this time, the surface of the light scattering material 4 is provided with unevenness 4c having a size smaller than the wavelength of the laser beam (that is, the dimensions of p and h in FIG. 14 are smaller than the wavelength of the laser beam). , The fluorescence is hardly reflected on the surface of the light scattering material 4 (the reflectance is less than 0.1%), and almost all is emitted to the outside of the light scattering material 4. The emitted fluorescence is reflected by the reflecting mirror 5 (see FIG. 13) and projected forward as a parallel light beam.

  On the other hand, the excited phosphor 3 generates heat at a very large density. In particular, in order to achieve high brightness as the lighting device 1, it is necessary to make the phosphor 3 small enough to be regarded as a point light source. In this case, the temperature of the small phosphor 3 may reach several hundred degrees Celsius. Therefore, a heat dissipation structure for efficiently radiating the heat of the phosphor 3 is required.

  In the present embodiment, as shown in FIG. 16, since the bottom surface of the phosphor 3 is in thermal contact with the metal plate 13 having good thermal conductivity, the heat of the phosphor 3 is indicated by an arrow B1 in FIG. As shown, heat is transferred to the metal plate 13 and efficiently radiated from the surface of the metal plate 13 into the air. Moreover, since the thermal conductivity of the light scattering material 4 covering the surface of the phosphor 3 is not as high as that of metal, it is higher than that of air. Therefore, as shown by an arrow B2, a part of the heat of the phosphor 3 is light scattering material 4. The heat is also transferred to the heat scattering material 4 and is dissipated. That is, the light scattering material 4 contributes to the heat dissipation of the phosphor 3. Since the phosphor 3 is made sufficiently thin, it is difficult for heat to stay inside, and heat can be efficiently transferred from the surface of the phosphor 3 to the metal plate 13 and the light scattering material 4.

  According to the illumination device of the present embodiment, the laser light is incident on the light scattering material 4 having the minute unevenness 4c before exciting the phosphor 3, so the first to sixth embodiments described above. In addition to the effect of reducing the coherence due to the scattering action by the light scattering particles inside the light scattering material 4 described in the above, the laser light reflected on the surface of the light scattering material 4 can be suppressed. Therefore, the leakage of the laser beam is surely prevented, and the safety for eyes is remarkably improved. As shown in FIG. 13, the laser light is incident from an oblique direction with respect to the central axis Z, but apparently has a size larger than the phosphor 3 and the light scattering material 4 covers the phosphor 3. Thus, even when the alignment of the laser irradiation device 2 is deviated and the optical axis L2 of the laser light is somewhat deviated, the probability that the laser light is directly reflected by the reflecting mirror 5 and goes outside is reduced.

  Moreover, according to the illumination device of the present embodiment, the heat generation of the phosphor 3 is actively dissipated by using the metal plate 13, so that the aging and scorching of the phosphor 3 are suppressed. In addition, since the metal plate 13 is exposed to the space outside the reflecting mirror 5, heat hardly accumulates in the recess 5a, which is suitable when the reflecting mirror 5 having a deep recess 5a is used as shown in FIG.

  Further, according to the illumination device of the present embodiment, since the phosphor unit 14 in which the phosphor 3 and the light scattering material 4 are integrated on the metal plate 13 is used, the convenience of handling the light scattering material 4 is increased. In addition, parts can be disassembled in units of units, and the labor for replacing parts is reduced.

<Eighth Embodiment>
Next, an eighth embodiment of the present invention will be described with reference to FIG. FIG. 17 is a side sectional view showing a schematic configuration of the illumination apparatus according to the eighth embodiment. In the illuminating device according to the present embodiment, the same parts as those of the illuminating device according to the seventh embodiment shown in FIG. 16 are denoted by the same reference numerals, and detailed description thereof is omitted.

  In the present embodiment, as shown in FIG. 17, a half reflector having a shape in which a parabolic mirror (see FIG. 16) is divided in half by a plane passing through the central axis Z is used. Although the area of the reflecting surface of the half reflector is halved, if the reflecting mirror 5 is supported by a plate-like support (see metal plate 13 in FIG. 17) having a plane passing through the central axis Z, the focal point is formed on the support. Therefore, it is easy to support the phosphor 3 at the focal point without using another holding member. In the present embodiment, the metal plate 13 constituting the phosphor unit 14 is used as the support.

  According to the illumination device of the present embodiment, since the phosphor 3 can be arranged at the focal position of the reflecting mirror 5, the utilization efficiency of parallel rays is improved. In particular, a parabolic mirror having a deep recess 5a is effective for producing beam-like light that does not spread far away with a small luminous flux.

  Further, according to the illumination device of the present embodiment, the surface area of the metal plate 13 constituting the phosphor unit 14 can be increased without increasing the size of the device, so that the heat dissipation efficiency of the phosphor 3 is improved.

  Although the lighting device according to the present invention has been described with reference to specific embodiments, the present invention relates to a method for guiding the type, wavelength, output, phosphor type, fluorescence wavelength, and laser light of a semiconductor laser element to the phosphor. It does not depend on it.

  For example, in the above embodiment, a case has been described where a plurality of semiconductor laser elements have the same intrinsic wavelength, but the semiconductor laser elements having different intrinsic wavelengths are used in combination, and the color necessary for illumination light is used. May be realized. For example, two intrinsic wavelengths of 405 nm (blue violet) and 650 nm (red) are used as a semiconductor laser element, SiAlON (blue green) is used as a phosphor, and a SiAlON phosphor is excited by a 405 nm laser beam. A blue-green light is emitted, but the lack of redness can be compensated by a semiconductor laser element of 650 nm.

  The present invention can be used in an illumination device that uses laser light as an excitation light source of a phosphor, and can be applied to, for example, a vehicle headlamp that requires high luminance.

DESCRIPTION OF SYMBOLS 1 Illuminating device 2 Laser irradiation apparatus 2a Semiconductor laser element 2b Collimator lens 2c, 2e Condensing lens 2d Optical fiber 2f Reflector 3 Phosphor 4 Light scattering material 5 Concave mirror 5a Concave 6 Cover 7 Filter 8 Condensing lens 9 Pipe 10 Pump 11 Secondary reflector

Claims (5)

In an illumination device that obtains visible light by exciting a phosphor with laser light emitted from a laser irradiation device and uses the visible light as illumination light,
The phosphor is disposed at a position away from the laser irradiation device,
A light scattering material is provided on the surface of the phosphor,
The laser light excites the phosphor after passing through the light scattering material,
The visible light emitted from the phosphor is transmitted through the light scattering material and then emitted to the outside.   The lighting device according to claim 1, wherein the phosphor radiates heat through a member provided on a surface facing the surface on which the laser light is irradiated.   The lighting device according to claim 2, wherein the member is a metal plate.   The illumination device according to claim 1, wherein unevenness is formed on a surface of the light scattering material.   The lighting device according to claim 1, wherein the light scattering material is glass or resin in which light scattering particles are dispersed.

Images