JP2015065144A - Light emitting unit, light emitting device, illumination device, and vehicle headlight - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a light emitting unit having improved efficiency of utilization of light.SOLUTION: A light emitting unit (3) comprises a light emission unit (8) that emits a fluorescence (L2) by the application of a laser beam (L1), and a wavelength selection filter (7) disposed facing the light emission unit (8). The filter (7) reflects the laser beam (L1) toward the light emission unit (8), and also allows the fluorescence (L2) emitted from the light emission unit (8) to pass therethrough.

Description

  The present invention relates to a light-emitting unit, a light-emitting device, a lighting device, and a vehicle headlamp that use fluorescence generated by irradiating a phosphor with excitation light as illumination light.

  In recent years, a semiconductor light emitting device such as a light emitting diode (LED) or a semiconductor laser (LD) is used as an excitation light source, and excitation light emitted from these excitation light sources is emitted to a light emitting unit including a phosphor. A light-emitting device that uses fluorescence generated by irradiation as illumination light has been proposed.

  A light emitting unit including such a phosphor has a structure in which fluorescence is extracted from an opposite surface opposite to an excitation light irradiation surface irradiated with excitation light (in this application, “transmission type”) due to the difference in the light emission method. And (2) a configuration in which fluorescence is extracted from an excitation light irradiation surface irradiated with excitation light (referred to as “reflection type” in the present application).

  As an example of a light emitting device including a reflective light emitting unit, there are light emitting devices disclosed in Patent Documents 1 and 2. In the light emitting device disclosed in Patent Document 1, a reflector for controlling the light distribution of the fluorescence generated by the light emitting unit is disposed between the excitation light source and the light emitting unit, and an excitation is provided in the opening of the reflector. A wavelength selective filter that removes light and selectively transmits fluorescence is attached. In this light emitting device, the excitation light emitted from the excitation light source is irradiated to the light emitting section through the light passage hole provided in the reflector, and the fluorescence generated by the irradiation is reflected by the reflector and controlled to a desired light distribution. Flood light.

  Here, in the light emitting device disclosed in Patent Document 1, since the light emitting unit is arranged so that the fluorescence extraction direction is opposite to the light projecting direction of the light emitting device, the fluorescent light generated by the light emitting unit is arranged. Needs to be reflected toward the light projecting direction of the light emitting device. For this reason, other light distribution control members such as lenses cannot be used in place of the reflector, and the usable light distribution control members are limited.

  On the other hand, Patent Document 2 discloses a light-emitting device in which an excitation light source is disposed between a light-emitting unit and a convex lens that controls light distribution of fluorescence generated by the light-emitting unit. In this light-emitting device, excitation light emitted from an excitation light source is irradiated onto a light-emitting unit, and fluorescence generated by the irradiation is controlled by a convex lens so as to emit light with a desired light distribution.

  According to the light emitting device disclosed in Patent Document 2, since the light emitting unit is arranged so that the fluorescence extraction direction is equal to the light projecting direction of the light emitting device, a light distribution control member such as a lens is preferably used. Can be used.

  FIG. 25 is a cross-sectional view showing a configuration of a conventional light emitting device 300 disclosed in Patent Document 2. As shown in FIG. As shown in FIG. 25, the light emitting device 300 includes an excitation light source 301, a collimating lens 305, a light emitting unit 308, and a convex lens 310.

  The light emitting unit 308 is of a reflective type in which fluorescence is extracted from the excitation light irradiation surface (upper surface) 308a irradiated with the excitation light L1, and the excitation light L1 is applied to the excitation light irradiation surface 308a of the light emission unit 308. In addition, an excitation light source 301 and a collimating lens 305 are disposed between the light emitting unit 308 and the convex lens 310.

  According to the light emitting device 300, the excitation light L1 emitted from the excitation light source 301 is irradiated onto the excitation light irradiation surface 308a of the light emitting unit 308, and the convex lens 310 emits the fluorescence emitted from the excitation light irradiation surface 308a to a desired light distribution. It can be controlled and projected.

JP 2005-150041 A (released on June 09, 2005) Japanese Unexamined Patent Publication No. 2010-2332044 (released on October 14, 2010)

  However, in the configuration in which the excitation light source 301 and the collimator lens 305 are disposed between the light emitting unit 308 and the convex lens 310, such as the light emitting device 300, there is a problem that the light use efficiency is lowered.

  That is, in the configuration in which the excitation light source 301 and the collimating lens 305 are disposed between the light emitting unit 308 and the convex lens 310, a part of the fluorescence emitted from the light emitting unit 308 is blocked by the excitation light source 301. Therefore, the fluorescence cannot be used efficiently.

  Further, in order to project the fluorescence emitted from the light emitting unit 308 with a Lambertian distribution without loss, it is preferable to arrange the convex lens 310 as close as possible to the light emitting unit 308, but between the light emitting unit 308 and the convex lens 310. In addition, since it is necessary to secure a space for arranging the excitation light source 301 and the collimating lens 305, it is difficult to arrange the convex lens 310 close to the light emitting unit 308.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a light-emitting unit with improved light use efficiency.

  In order to solve the above-described problem, a light-emitting unit according to an aspect of the present invention includes a light-emitting unit that emits fluorescence when irradiated with excitation light, and an optical plate that is disposed to face the light-emitting unit. The plate reflects the excitation light emitted from the excitation light source toward the light emitting part, and transmits the fluorescence emitted from the light emitting part by irradiation of the excitation light.

  According to one embodiment of the present invention, it is possible to provide a light emitting unit with improved light use efficiency.

FIG. 1 is a cross-sectional view illustrating a configuration of the light emitting device according to the first embodiment. FIGS. 2A and 2B are cross-sectional views showing the configuration of the wavelength selective filter shown in FIG. FIG. 3 is a graph for explaining the wavelength selectivity of the wavelength selection filter. FIG. 4 is a cross-sectional view showing the operation of the wavelength selection filter. FIG. 5 is a cross-sectional view showing a configuration of a headlamp of an automobile provided with a light emitting device. FIG. 6 is a cross-sectional view showing an unknown configuration when a known wavelength selection filter is applied to the conventional light emitting device shown in FIG. FIG. 7 is a cross-sectional view showing an unknown configuration obtained by improving the light emitting device shown in FIG. FIG. 8 is a cross-sectional view illustrating a configuration of a light emitting device in which an optical fiber is omitted. FIG. 9 is a cross-sectional view illustrating a configuration of a light emitting device including a plurality of laser elements. FIG. 10 is a cross-sectional view illustrating a configuration of a light emitting device including a projection lens. FIG. 11 is a cross-sectional view illustrating a configuration of a light emitting device including a substantially hemispherical wavelength selection filter. FIG. 12 is a cross-sectional view illustrating a configuration of the light emitting device of the second embodiment. 13 is a perspective view showing the configuration of the light intensity detection unit shown in FIG. 12, FIG. 13A shows the appearance of the light intensity detection unit, and FIG. 13B shows the configuration of FIG. The state which removed the cap shown by (a) is shown. FIG. 14 is a cross-sectional view illustrating a configuration of the light emitting device according to the third embodiment. FIG. 15 is a cross-sectional view showing a modification of the light emitting device shown in FIG. FIG. 16 is a cross-sectional view showing another modification of the light emitting device shown in FIG. FIG. 17 is a cross-sectional view illustrating a configuration of the light emitting device according to the fourth embodiment. FIGS. 18A to 18C are schematic views for explaining an arrangement example of optical elements having optical surfaces that are not flat. FIG. 19 is a cross-sectional view illustrating a configuration of the light emitting device of the fifth embodiment. FIG. 20 is a graph for explaining the wavelength selectivity of the absorption filter. FIG. 21A is a plan view showing the emission end of the optical fiber shown in FIG. 19, and FIG. 21B is a plan view showing the light emitting section shown in FIG. 22 (a) and 22 (b) are plan views for explaining a modification of the light emitting section shown in FIG. 21 (b). FIG. 23 is a cross-sectional view illustrating a configuration of the light emitting device of the sixth embodiment. 24 is a cross-sectional view showing a modification of the side wall shown in FIG. FIG. 25 is a cross-sectional view illustrating a configuration of a conventional light emitting device. is there.

Embodiment 1
An embodiment of the present invention will be described below with reference to FIGS. In the present embodiment, a light emitting device 100 including the light emitting unit of the present invention will be described as an example.

<Configuration of Light Emitting Device 100>
First, the light emitting device 100 of the present embodiment will be described with reference to FIG.

  FIG. 1 is a cross-sectional view illustrating a configuration of a light emitting device 100 according to the present embodiment. As shown in FIG. 1, the light emitting device 100 includes a laser element (excitation light source) 1, an optical fiber (light guide) 2, and a light emitting unit 3, and the laser element 1 and the light emitting unit 3 are connected by the optical fiber 2. It is a configuration. Hereinafter, the structure of each part with which the light-emitting device 100 is provided is demonstrated.

(Laser element 1)
The laser element 1 is a light emitting element that functions as an excitation light source that emits laser light (excitation light). The laser element 1 may have one light emitting point on one chip, or may have a plurality of light emitting points on one chip. The wavelength of the laser light L1 emitted from the laser element 1 is, for example, 365 nm to 439 nm, preferably 390 nm (blue violet) to 410 nm (blue violet), but is not limited thereto, and the light emitting unit 8 included in the light emitting unit 3. What is necessary is just to select suitably according to the kind of the fluorescent substance included in (3), the wavelength selectivity of the wavelength selection filter 7 mentioned later, etc. A preferred specific example of the wavelength of the laser beam L1 emitted from the laser element 1 will be described later together with the characteristics of the wavelength selection filter 7.

  The laser element 1 is connected to a heat sink 11. The heat sink 11 radiates the heat generated in the laser element 1 through the radiation fins 12 and the like. For this reason, it is preferable to use a metal material such as aluminum having high thermal conductivity for the heat sink 11.

  The heat radiation fins 12 are provided in the heat sink 11 and function as a heat radiation mechanism that radiates the heat of the heat sink 11 into the air. The heat radiating fins 12 have a plurality of heat radiating plates, and increase the heat radiation efficiency by increasing the contact area with the atmosphere. Note that, similarly to the heat sink 11, it is preferable to use a material having high thermal conductivity for the radiation fin 12.

  The laser element 1 generates heat when emitting laser light, but its performance cannot be sufficiently exhibited in a high temperature environment. Therefore, by providing the heat sink 11 and the radiation fins 12, it is possible to prevent the laser element 1 from becoming high temperature. Note that a water cooling mechanism or a forced air cooling mechanism may be used as the heat dissipation mechanism of the laser element 1.

  Here, although one laser element 1 is used as an excitation light source of the light emitting device 100 in the present embodiment, the present invention is not limited to this.

  For example, the following method may be used as a method for increasing the excitation intensity. That is, a plurality of laser elements 1 may be used, and an optical member such as a lens or a mirror may be used to couple the laser light L1 emitted from the plurality of laser elements 1 to the optical fiber 2. Or you may couple the laser beam L1 radiate | emitted from the several laser element 1 to each of the several optical fiber 2 made into the bundle shape.

  Further, for example, an LED (Light Emitting Diode) may be used as the excitation light source. However, since the laser element 1 has better coupling efficiency to the optical fiber 2 than the LED, it is preferable to use the laser element 1 as an excitation light source.

(Optical fiber 2)
The optical fiber 2 is a light guide that guides the laser light L 1 emitted from the laser element 1 to the light emitting unit 3. The optical fiber 2 has an incident end 2a that receives the laser light L1 emitted from the laser element 1, and an emission end 2b that emits the laser light L1 incident from the incident end 2a. The incident end 2 a is connected to the laser element 1, and the incident end 2 a is connected to the light emitting unit 3.

  The optical fiber 2 has a two-layer structure in which an inner core is covered with a clad having a refractive index lower than that of the core. The core is mainly composed of quartz glass (silicon oxide) with little absorption loss of the laser beam L1. The clad is mainly composed of quartz glass or a synthetic resin material having a refractive index lower than that of the core. For example, the optical fiber 2 is made of quartz having a core diameter of 200 μm, a cladding diameter of 240 μm, and a numerical aperture NA of 0.22, but the structure, thickness, and material of the optical fiber 2 are as described above. It is not limited, The cross section perpendicular | vertical with respect to the major axis direction of the optical fiber 2 may be arbitrary shapes, such as a rectangle.

  When a plurality of laser elements 1 are used, a bundle fiber in which a plurality of optical fibers 2 optically coupled to the plurality of laser elements 1 are bundled may be used. In this case, it is preferable to use a light guide unit in which the bundle fiber and the multimode fiber are optically coupled by bringing the exit end of the bundle fiber close to or in contact with the multimode fiber.

  The multimode fiber guides a plurality of laser beams L1 incident from a plurality of bundled optical fibers 2. At this time, the plurality of laser beams L1 in the multimode fiber propagate while being repeatedly reflected in the multimode fiber. Therefore, the plurality of laser beams L1 are mixed by being guided through the multimode fiber, and if the length of the multimode fiber is appropriately set, the laser beam L1 has a continuous and smooth intensity distribution. Thus, the light is emitted from the emission end face of the multimode fiber.

  As described above, by using the light guide unit in which the bundle fiber and the multimode fiber are optically coupled, the plurality of laser beams L1 emitted from the light emitting points of the plurality of laser elements 1 are continuously smoothed. Laser light L1 emitted from a single light emitting point (outgoing end face of a multimode fiber) having a strong intensity distribution can be generated. In the present specification, a single light emitting point refers to a light emitting point that does not have a maximum value that is 50% or more of the peak intensity. Therefore, the laser light irradiation surface 8a of the light emitting unit 8 can be irradiated with the laser light L1 having a continuous and smooth intensity distribution. Therefore, even if the light emitting unit 8 is irradiated with the high output laser light L1, A part of the light emitting unit 8 is not locally excited.

  Therefore, it is possible to suppress the deterioration of the light emitting unit 8 and the light emission efficiency while increasing the output of the fluorescence L2. Moreover, since a part of the light emission part 8 is not excited locally, the brightness | luminance nonuniformity of the fluorescence L2 emitted can be suppressed.

  In addition, you may use members other than the optical fiber 2 as a light guide part which optically couple | bonds the laser element 1 and the light emission unit 3, and the kind of light guide part is not limited. Further, as will be described later, the laser light L1 emitted from the laser element 1 may be directly introduced into the light emitting unit 3 without using the optical fiber 2.

(Light emitting unit 3)
The light emitting unit 3 emits the fluorescence generated by irradiating the light emitting unit 8 including the phosphor with the laser light L1 emitted from the laser element 1. The light emitting unit 3 includes a heat dissipation base (mounting unit) 4, a lens 5, a mirror (reflecting mirror) 6, a wavelength selection filter (optical plate) 7, and a light emitting unit 8.

(Heat dissipation base 4)
It is a plate-like support member on which the heat dissipation base 4 and the light emitting unit 8 are placed, and is made of a material having high thermal conductivity such as metal (aluminum, stainless steel, copper or iron), for example. The heat dissipation base 4 has a mounting surface 4a on which the light emitting unit 8 is mounted, and the light emitting unit 8 is mounted in a state of being in contact with the mounting surface 4a. Therefore, the heat radiating base 4 can efficiently conduct and dissipate heat generated by the light emitting unit 8.

  Note that the heat dissipation base 4 is not limited to one made of metal, and may be a member containing a substance (ceramics or the like) having high thermal conductivity other than metal. However, it is preferable that the mounting surface 4a in contact with the light emitting unit 8 functions as a reflecting surface. Since the mounting surface 4a in contact with the light emitting unit 8 is a reflecting surface, the laser light L1 that is irradiated with the laser light L1 and incident from the laser light irradiation surface 8a that is the upper surface of the light emitting unit 8 is converted into fluorescence L2. After that, the emitted fluorescence L2 can be reflected by the reflecting surface and directed to the wavelength selection filter 7. Alternatively, the laser beam L1 incident from the laser beam irradiation surface 8a can be reflected by the reflecting surface and again converted into fluorescence toward the inside of the light emitting unit 8.

  In addition, although not shown in figure, the thermal radiation base 4 may be provided with the thermal radiation fin. The radiation fins function as a cooling unit that cools the radiation base 4. The heat radiating fin has a plurality of heat radiating plates and increases the heat radiation efficiency by increasing the contact area with the atmosphere. The cooling part that cools the heat radiating base 4 is not limited as long as it has a cooling (heat radiating) function, and instead of the heat radiating fins, a heat pipe, a water cooling method, or a forced air cooling method may be used.

  The heat dissipation base 4 is formed with an internal path 40 that is open in a region of the mounting surface 4a where the light emitting unit 8 is not mounted. The internal path 40 is a tubular path for allowing the laser light L1 to pass through, and the laser light L1 introduced from the start end (other end) side is led out from the opening 40a on the end end (one end) side.

  In the present embodiment, the starting end of the internal path 40 is located inside the heat dissipation base 4, extends from the starting end in the in-plane direction, and bends from the in-plane direction to the mounting surface 4 a side (about 135 ° at the bent portion). And is opened at the mounting surface 4a.

  The outgoing end 2b of the optical fiber 2 penetrating from the side surface of the heat dissipation base 4 is connected to the starting end of the internal path 40, and the laser light L1 introduced from the starting end side passes through the internal path 40 and opens. Derived from the unit 40 a toward the wavelength selection filter 7. In the internal path 40, the lens 5 and the mirror 6 are arranged in this order from the upstream in the traveling direction of the laser light L1.

(Lens 5)
The lens 5 is an optical member for adjusting (for example, reducing) the beam diameter (irradiation range) of the laser light L1 so that the laser light L1 is appropriately irradiated to the mirror 6. The lens 5 is disposed in the internal path 40 of the heat radiating base 4, and irradiates the mirror 6 by controlling the beam diameter and optical path of the laser light L 1 emitted from the emission end 2 b of the optical fiber 2. The lens 5 is composed of, for example, a convex lens.

  By controlling the beam diameter with the lens 5 provided, it becomes easy to adjust the size of the spot of the laser light L1 finally irradiated to the light emitting section 8.

(Mirror 6)
The mirror 6 reflects the laser light L1 toward the wavelength selection filter 7. Specifically, the mirror 6 has a flat reflecting surface, is disposed at a bent portion of the internal path 40, and the laser beam L1 introduced from the start end side of the internal path 40 is directed to the opening 40a. Reflect toward you. Thereby, the laser beam L1 can be derived from the opening 40a and directed to the wavelength selection filter 7.

  By providing the mirror 6, it becomes easy to adjust the incident angle of the laser light L <b> 1 with respect to the wavelength selection filter 7 by changing the installation angle (tilt) of the mirror 6, so that the emission end 2 b itself of the optical fiber 2 is installed. As compared with the case where the angle is changed, the adjustment of the incident angle of the laser light L1 with respect to the wavelength selection filter 7 is facilitated. Further, by folding the laser light L1 in the light emitting unit 3 by the mirror 6, the volume and size of the light emitting unit 3 can be significantly reduced, and the layout inside the light emitting unit 3 can be freely performed.

  Instead of the mirror 6, another optical member such as a dielectric multilayer mirror, a dielectric multilayer mirror, or a concave mirror may be used. As a result, various functions can be added to the light emitting unit 3 while keeping the size of the light emitting unit 3 small. A configuration using a dielectric multilayer mirror, a dielectric multilayer mirror, or a concave mirror will be described later.

(Wavelength selection filter 7)
The wavelength selection filter 7 is a light-transmitting plate-like translucent member that is disposed so as to face the laser light irradiation surface 8 a of the light emitting unit 8. The wavelength selection filter 7 has an outer peripheral portion supported by the support portion 4 b of the heat radiating base 4, and is disposed substantially parallel to the laser light irradiation surface 8 a of the light emitting portion 8.

  The wavelength selection filter 7 reflects the laser light L1 and transmits the fluorescence L2. That is, the wavelength selection filter 7 has wavelength selectivity that reflects the laser light L1 and transmits the fluorescence L2.

  Due to such wavelength selectivity of the wavelength selection filter 7, the wavelength selection filter 7 reflects the laser beam L1 derived from the opening 40a toward the light emitting unit 8, and irradiates the light emitting unit 8 with the laser beam L1. . At this time, the incident angle of the laser beam L1 with respect to the wavelength selection filter 7 is adjusted so that the laser beam L1 reflected by the wavelength selection filter 7 is irradiated onto the laser beam irradiation surface 8a of the light emitting unit 8.

  Thus, the wavelength selection filter 7 reflects the laser light L1 derived from the opening 40a formed on the placement surface 4a on which the light emitting unit 8 is placed, toward the light emitting unit 8. Therefore, since it becomes easy to dispose the laser element 1 on the heat radiating base 4 side with respect to the light emitting unit 8, the laser element 1 can be suitably disposed at a position that does not block the fluorescence L2 emitted from the light emitting unit 8. it can.

  Further, the wavelength selection filter 7 transmits the fluorescence L2 emitted from the laser light irradiation surface 8a of the light emitting unit 8 by irradiation with the laser light L1. At this time, it is preferable that the wavelength selection filter 7 reflects the laser beam L1 that has not been converted into the fluorescence L2 out of the laser beam L1 irradiated to the light emitting unit 8 to the light emitting unit 8 side. Most of the laser beam L1 is absorbed by the phosphor and converted into fluorescence L2 by the light emitting unit 8. However, there may be a case where a part of the laser beam L1 is not converted for some reason. Even in such a case, it is possible to prevent the laser light L1 from leaking to the outside by reflecting the laser light L1 that has not been converted to the fluorescence L2 to the light emitting unit 8 side by the wavelength selection filter 7.

  The wavelength selective filter 7 having such wavelength selectivity is realized by a multilayer structure in which thin layers having different refractive indexes are combined. Details of the wavelength selection filter 7 will be described later.

(Light Emitting Unit 8)
The light emitting unit 8 emits fluorescence L2 when irradiated with the laser beam L1, and includes a phosphor that is excited by the laser beam L1 and emits fluorescence L2. For example, the light-emitting portion 8 is one in which a phosphor is dispersed inside a sealing material, or one in which a phosphor is solidified. Since the light emitting unit 8 converts the laser light L1 into fluorescence L2, it can be said that it is a wavelength conversion member.

  As the phosphor of the light emitting unit 8, for example, an oxynitride phosphor (for example, sialon phosphor) or a III-V group compound semiconductor nanoparticle phosphor (for example, indium phosphorus: InP) can be used. These phosphors are preferable because they have high heat resistance against the high-power (and / or light density) laser light L1 emitted from the laser element 1. However, the phosphor of the light emitting unit 8 is not limited to the above-described phosphor, and may be other phosphors such as a nitride phosphor.

  Moreover, the sealing material of the light emission part 8 is resin materials, such as a glass material (inorganic glass, organic-inorganic hybrid glass), a silicone resin, for example. Low melting glass may be used as the glass material. The sealing material is preferably highly transparent, and when the laser beam has a high output, a material having high heat resistance is preferable.

  The light emitting unit 8 is disposed on the mounting surface 4a of the heat dissipation base 4 so that the laser light irradiation surface 8a is irradiated with the laser light L1 and mainly emits fluorescence from the laser light irradiation surface 8a. That is, the light emitting unit 8 functions as a reflective light emitting unit.

  In the light emitting device 100 having such a configuration, the laser light L1 emitted from the laser element 1 is introduced into the internal path 40 of the heat dissipation base 4 via the optical fiber 2. The beam diameter of the laser beam L1 introduced into the internal path 40 is adjusted by the lens 5, reflected by the mirror 6, and led out from the opening 40a. The laser light L1 derived from the opening 40a is reflected toward the light emitting unit 8 by the wavelength selection filter 7, and is irradiated on the light emitting unit 8. The fluorescence L2 generated by this irradiation is emitted from the laser light irradiation surface 8a, passes through the wavelength selection filter 7, and is emitted to the outside.

<Details of wavelength selection filter 7>
Next, details of the wavelength selection filter 7 of the present embodiment will be described with reference to FIGS.

(Configuration of wavelength selection filter 7)
2A and 2B are cross-sectional views showing the configuration of the wavelength selective filter 7 shown in FIG. As shown in FIGS. 2A and 2B, the wavelength selection filter 7 includes a substrate 71, a multilayer coating 72, and a single-layer AR (single-layer AR) coating 73.

  As shown in FIG. 2A, the wavelength selection filter 7 has, for example, a surface on the light emitting unit 8 side of the substrate 71 that is coated with a multilayer film 72, and the surface of the substrate 71 opposite to the light emitting unit 8. A single-layer AR (single-layer antireflection) coat 73 is applied thereto.

  The substrate 71 is a substrate that transmits the fluorescence L2 and can form the multilayer coating 72 and the single-layer AR coating 73 film 13b. As the substrate, for example, BK7, synthetic quartz, white plate glass (for example, B270, D263Teco, BSL7) or the like can be preferably used.

The multilayer film coat 72 is a multilayer film in which a plurality of thin film layers such as a SiO ₂ film and a TiO ₂ film are multilayered. As described above, the wavelength selection filter 7 has the wavelength selectivity of reflecting the laser beam L1 and transmitting the fluorescence L2. In order to realize this wavelength selectivity, the multilayer coating 72 is obtained, for example, by alternately laminating a material having a high refractive index and a material having a low refractive index, and AlN, SiO ₂ , SiN, ZrO ₂ , TiO ₂ , Examples thereof include a material containing at least one selected from Al ₂ O ₃ , GaN, ZnS and the like.

  Note that the number of layers of the multilayer film coat 72 is determined so that desired wavelength selectivity is obtained, and the combination of the film type and film thickness of each layer is optimized.

  The single-layer AR coat 73 is a single-layer film that suppresses the scattering and absorption of the fluorescence L2 on the substrate 71 and increases the transmitted light amount of the fluorescence L2 that passes through the substrate 71. The material of the single-layer AR coat 73 is appropriately selected according to the wavelength of the fluorescent light L2 to be transmitted.

  As shown in FIG. 2B, the wavelength selection filter 7 has a single-layer AR coat 73 on the surface of the substrate 71 on the light emitting unit 8 side, and is opposite to the light emitting unit 8 of the substrate 71. A multilayer coating 72 may be applied to the surface. However, in order to obtain the wavelength selectivity of reflecting the laser beam L1 and transmitting the fluorescence L2, it is preferable to coat the surface of the substrate 71 on the light emitting portion 8 side with a multilayer film as shown in FIG. 72 is preferably applied.

(Wavelength selectivity of wavelength selective filter 7)
FIG. 3 is a graph for explaining the wavelength selectivity of the wavelength selection filter 7. FIG. 3 exemplifies the relationship between the wavelength and the transmittance when the incident angle of the incident light with respect to the wavelength selection filter 7 is 0 °, 10 °, 20 °, 30 °, and 40 °, and the horizontal axis is incident. The wavelength of light is shown, and the vertical axis shows the transmittance of the light. The incident angle means the angle of incident light with respect to the normal line of the wavelength selection filter 7.

  As shown in FIG. 3, the wavelength selectivity of the wavelength selection filter 7 depends on the wavelength of incident light and the incident angle. For example, the wavelength selection filter 7 reflects 90% or more of light with a wavelength of 410 nm or less incident at an incident angle of 30 ° or less. Alternatively, the wavelength selection filter 7 transmits 90% or more of light having a wavelength of 440 nm or more incident at an incident angle of 50 ° or less.

  Therefore, it is preferable to use the laser beam L1 having a wavelength range that is easily reflected by the wavelength selection filter 7, for example, a laser beam having a wavelength range of 390 nm to 410 nm can be suitably used. Specifically, when the wavelength selective filter 7 is irradiated with laser light L1 having a wavelength of 405 nm at an incident angle of 40 °, 99% or more of the laser light L1 irradiated to the wavelength selective filter 7 is reflected by the wavelength selective filter 7. Thus, the light emitting unit 8 can be directed.

  As described above, by optimizing the laminated structure of the wavelength selection filter 7, the wavelengths of the laser light L1 and the fluorescence L2, and the incident angle of the laser light L1 with respect to the wavelength selection filter 7, the short wavelength side including the laser light L1 can be obtained. Light in the wavelength range can be reflected, and light in the wavelength range on the long wavelength side including the fluorescence L2 can be transmitted.

(Operation of the wavelength selection filter 7)
FIG. 4 is a cross-sectional view showing the operation of the wavelength selection filter 7. As described above, the wavelength selection filter 7 has wavelength selectivity that reflects the laser light L1 and transmits the fluorescence L2. Therefore, as shown in FIG. 4, the wavelength selection filter 7 reflects the laser light L1 derived from the opening 40a. At this time, the incident angle of the laser light L1 with respect to the wavelength selection filter 7, the arrangement positions of the light emission unit 8 and the wavelength selection filter 7 and the like are adjusted in advance so that the reflected laser light L1 is reflected toward the light emission unit 8. .

  In addition, the wavelength selection filter 7 transmits the fluorescence L2 emitted from the laser light irradiation surface 8a of the light emitting unit 8 by the irradiation of the laser light L1, and emits it to the outside. At this time, the laser beam L1 reflected or scattered by the laser beam irradiation surface 8a without being absorbed by the light emitter 8 or emitted from the light emitter 8 without being converted into the fluorescence L2 once incident on the light emitter 8 is emitted. The stray light component of the laser beam L1 such as the laser beam L1 is reflected by the wavelength selection filter 7 and most of it is confined inside the light emitting unit 3. Therefore, leakage of the stray light component of the laser light L1 to the outside of the light emitting unit 3 is suppressed.

  Note that, as described above, this embodiment is preferably implemented when only the fluorescence L2 is selectively emitted to the outside without causing the laser light L1 to leak out of the light emitting unit 3. For example, when the illumination light is white, it is preferable to select a wavelength of 390 to 410 nm as the laser light L1 that has low visibility and can efficiently excite a phosphor that emits visible light.

  Thus, since the light emitting device 100 includes the wavelength selective filter 7 having the wavelength selectivity of reflecting the laser light L1 and transmitting the fluorescence L2, the light emitting device 100 is provided between the light emitting unit 8 and the wavelength selective filter 7. There is no need to arrange an excitation light source for irradiating the light emitting unit 8 with excitation light.

  Therefore, in the light emitting device 100, a part of the fluorescence L2 emitted from the light emitting unit 8 is not blocked by the excitation light source, so that the fluorescence L2 can be used efficiently.

  Further, in the light emitting device 100, it is not necessary to secure a space for arranging the excitation light source between the light emitting unit 8 and the wavelength selection filter 7, so that the wavelength selection filter 7 can be arranged close to the light emitting unit 8. It becomes possible. Accordingly, when the fluorescent light L2 that has passed through the wavelength selection filter 7 is projected by a light distribution control member such as a projection lens, the projection lens and the like can be disposed close to the light emitting unit 8, so Fluorescence L2 emitted in a cyan distribution can be incident on a projection lens or the like without loss and projected.

<Application example of light emitting device 100>
Next, an application example of the light emitting device 100 of the present embodiment will be described with reference to FIG.

  FIG. 5 is a cross-sectional view showing a configuration of an automobile headlamp (vehicle headlamp) 200 including the light emitting device 100. As shown in FIG. 5, the headlamp 200 includes a light emitting device 100, a metal base 201, and a reflector 202.

(Metal base 201)
The metal base 201 is a support member that supports the light emitting unit 3 and the reflector 202, and is made of metal (for example, aluminum, stainless steel, copper, or iron). Therefore, the metal base 201 has high thermal conductivity, and can efficiently conduct and dissipate heat generated by the light emitting unit 3.

  The metal base 201 is provided with a recess on the surface that supports the reflector 202, and the light emitting unit 3 is fixed to the recess. At this time, the light emitting unit 3 is fixed to the recess so that the height of the surface of the metal base 201 that supports the reflector 202 and the wavelength selection filter 7 supported by the support portion 4b provided on the heat dissipation base 4 coincide. Is done.

(Reflector 202)
The reflector 202 projects the fluorescence L2 emitted from the light emitting device 100. The reflector 202 may be, for example, a member having a metal thin film formed on the surface thereof or a metal member.

  The reflector 202 has at least a part of a partial curved surface obtained by cutting a reflection curved surface formed by rotating the parabola with the axis of symmetry of the parabola as a rotation axis, along a plane parallel to the rotation axis. Included in the reflection curved surface The reflector 202 has a semicircular opening 202a in the direction in which the fluorescence L2 emitted from the light emitting device 100 is projected.

  The fluorescent light L2 generated by the light emitting unit 8 disposed at a substantially focal position of the reflector 202 is projected by the reflector 202 from the opening 202a toward the traveling direction of the vehicle by forming a light beam nearly parallel. . Thereby, the fluorescence L2 generated by the light emitting unit 8 can be efficiently projected within a narrow solid angle.

  The light emitting unit 3 can be easily separated from the metal base 201 or the reflector 202 and can be easily replaced with a normal light emitting unit 3 in the event of non-lighting.

  As described above, in the light emitting unit 3, the outer peripheral portion of the wavelength selection filter 7 is supported by the support portion 4 b of the heat dissipation base 4, and the wavelength selection filter 7 and the heat dissipation base 4 are integrated. Therefore, the gap between the wavelength selection filter 7 and the heat dissipation base 4 is surrounded by a light-shielding support 4b (that is, when the light emitting unit 3 is viewed from the side, the wavelength selection filter 7 and the heat dissipation base 4 The gap is not visible from the outside.) As a result, the laser beam L1 is completely confined inside the light emitting unit 3, and the laser beam L1 does not leak to the outside. Therefore, the user can safely handle the light emitting unit 3 without being exposed to the laser beam L1. Can do.

  The reflector 202 may include a full parabolic mirror having a circular opening or a part thereof. In addition to the parabolic mirror, an elliptical surface, a free-form surface shape, or a multi-faceted one (multi-reflector) can be used. Furthermore, a part that is not a curved surface may be included in a part of the reflector 202. Alternatively, the reflector 202 may be one that magnifies and projects an image of the light emitting unit 8 disposed on the reference plane of the reflector.

  Although not shown, the headlamp 200 may be further provided with a lens or the like for controlling the angle range for projecting the opening 202a of the reflector 202.

  The law stipulates that the illumination light of the headlamp 200 must be white having a predetermined range of chromaticity. For this reason, the light emitting unit 8 includes a phosphor selected so that the illumination light is white. For example, when blue, green, and red phosphors are included in the light emitting unit 8 and irradiated with a laser beam L1 of 405 nm, white light is obtained.

  In addition, you may apply the light-emitting device 100 to vehicle headlamps other than a motor vehicle. Furthermore, the light emitting device 100 may be applied to other lighting devices, for example, headlamps of moving objects other than vehicles (for example, humans, ships, aircraft, submersibles, rockets, etc.), searchlights, projectors, indoors You may apply to lighting fixtures (a downlight, a stand lamp, etc.).

<Effect of the light emitting device 100>
Next, the effect of the light emitting device 100 will be described with reference to FIGS. 6 and 7.

  As described above, the conventional light emitting device 300 in which the excitation light source 301 and the collimator lens 305 are disposed between the light emitting unit 308 and the convex lens 310 as shown in FIG. It was.

  FIG. 6 is a cross-sectional view showing an example of a configuration when a known wavelength selection filter 307 is applied to the conventional light emitting device 300. As shown in FIG. 6, when a known wavelength selection filter 307 that removes the excitation light L <b> 1 is applied to the conventional light emitting device 300, the wavelength selection filter 307 is disposed on the incident surface side of the convex lens 310. However, in the configuration in which the known wavelength selection filter 307 is applied, the excitation light source 301 and the collimator for irradiating the excitation light L1 to the excitation light irradiation surface 308a of the light emission unit 308 between the light emission unit 308 and the wavelength selection filter 307. Since the lens 305 still needs to be arranged, the above problem cannot be solved.

  Further, as shown in FIGS. 7A and 7B, a mirror that reflects the excitation light L1 toward the excitation light irradiation surface 308a of the light emitting unit 308 instead of the excitation light source 301 and the collimating lens 305. A configuration in which 306 is arranged is also conceivable. However, even in such a configuration, since it is necessary to arrange the mirror 306 between the light emitting unit 308 and the wavelength selection filter 307, a part of the fluorescence emitted from the light emitting unit 308 is blocked by the mirror 306. It is done. Further, since it is necessary to secure a space for disposing the mirror 306 between the light emitting unit 308 and the wavelength selection filter 307, the convex lens 310 (not shown) cannot be disposed sufficiently close to the light emitting unit 308. Therefore, even if it is the structure which replaced with the excitation light source 301 and has arrange | positioned the mirror 306, said subject cannot be solved.

  Therefore, the light-emitting unit 3 included in the light-emitting device 100 of the present embodiment includes a light-emitting unit 8 that emits fluorescence L2 when irradiated with the laser light L1, and a wavelength selection filter 7 that is disposed to face the light-emitting unit 8. The selection filter 7 reflects the laser light L1 emitted from the laser element 1 toward the light emitting unit 8, and transmits the fluorescence L2 emitted from the light emitting unit 8 by the irradiation of the laser light L1.

  In the light emitting device 100, the light emitting unit 3 includes a wavelength selection filter 7 disposed so as to face the light emitting unit 8, and the wavelength selection filter 7 reflects the laser light L <b> 1 toward the light emitting unit 8, and laser It has wavelength selectivity that transmits the fluorescence L2 emitted from the light emitting unit 8 by the irradiation of the light L1.

  Therefore, by reflecting the laser light L1 emitted from the laser element 1 toward the light emitting part 8 by the wavelength selection filter 7, the light emitting part 8 can be irradiated with the laser light L1 to generate the fluorescence L2. Therefore, it is not necessary to arrange an excitation light source or the like for irradiating the light emitting unit 8 with excitation light between the light emitting unit 8 and the wavelength selection filter 7.

  Therefore, in the light emitting device 100, a part of the fluorescence emitted from the light emitting unit is not blocked by the excitation light source or the like, so that the fluorescence L2 can be used efficiently.

  Further, in the light emitting device 100, since it is not necessary to secure a space for arranging an excitation light source or the like between the light emitting unit 8 and the wavelength selection filter 7, the light is transmitted through the wavelength selection filter 7 by a light distribution control member such as a projection lens. When projecting the fluorescent light L <b> 2, the projection lens or the like can be disposed close to the light emitting unit 8. Therefore, the fluorescent light L2 emitted from the light emitting unit 8 with a Lambertian distribution can be incident on the projection lens or the like without loss, and can be projected.

  Therefore, according to the present embodiment, it is possible to realize the light emitting device 100 in which the utilization efficiency of the fluorescence L2 is improved.

  Moreover, according to this embodiment, as shown in FIG. 5, it can be set as the small light emission unit 3 which can be replaced | exchanged easily independently of the reflector 202 and a projection lens. In such a configuration, the laser light L1 can be completely confined inside the light emitting unit 3, so that there is an advantage that leakage of the laser light L1 to the outside does not occur. In contrast, conventionally, the laser light source and the light emitting unit are not independent of the reflector and the projection lens, and the laser light propagates through the space inside the reflector and the space between the light emitting unit and the projection lens. It was. For this reason, when the user accesses the reflector or the projection lens, the user may be exposed to the laser beam. In addition, the point which can be comprised as a replaceable unit independent of a reflector and a projection lens is the same also in the structure of the following modifications and other Examples.

<Modification>
Next, modified examples of the light emitting device 100 will be described with reference to FIGS. A laser emitted from the laser element 1 may be introduced into the light emitting unit 3 without using the optical fiber 2.

(Modification 1)
FIG. 8 is a cross-sectional view illustrating a configuration of the light emitting device 101 that does not use the optical fiber 2. As shown in FIG. 8, the light emitting device 101 is configured to introduce laser light L <b> 1 emitted from the laser element 1 into the light emitting unit 3 without passing through the optical fiber 2.

  In the light emitting device 101, the internal path 40 formed in the heat dissipation base 4 is formed as a through hole. The internal path 40 penetrates the heat radiating base 4 obliquely in the out-of-plane direction, and is opened on the mounting surface (upper surface) 4a of the heat radiating base 4 and the lower surface facing the mounting surface 4a.

  In the light emitting device 101, the laser element 1 is disposed below the heat radiating base 4 so that the optical axis coincides with the axial direction of the internal path 40. Therefore, the laser beam L1 emitted from the laser element 1 is introduced into the internal path 40 and is led out toward the wavelength selection filter 7 from the opening 40a.

  Further, in the light emitting device 101, the lens 5 for adjusting the beam diameter or the like of the laser light L <b> 1 is attached to the emission end portion of the laser element 1.

  In the light emitting device 101, the laser beam L <b> 1 emitted from the laser element 1 is introduced into the internal path 40 of the heat radiating base 4, the beam diameter of which is adjusted by the lens 5 and formed as a through hole. The laser beam L1 introduced into the internal path 40 travels straight through the internal path 40 and is led out from the opening 40a. The laser light L1 derived from the opening 40a is reflected toward the light emitting unit 8 by the wavelength selection filter 7, and is irradiated on the light emitting unit 8. The fluorescence L2 generated by this irradiation is extracted from the laser light irradiation surface 8a, passes through the wavelength selection filter 7, and is emitted to the outside.

  According to the light emitting device 101, since the optical fiber 2 and the mirror 6 are not used, the configuration of the light emitting device 101 can be simplified and the manufacturing cost can be reduced.

(Modification 2)
Further, the number of laser elements 1 is not limited to one, and a plurality of laser elements 1 may be used.

  FIG. 9 is a cross-sectional view illustrating a configuration of a light emitting device 102 including a plurality of laser elements. As shown in FIG. 9, the light emitting device 102 includes two laser elements 1.

  In the light emitting device 102, the laser light L <b> 1 emitted from each laser element 1 is individually introduced into two internal paths 40 formed in the heat dissipation base 4. The laser light L1 introduced into each internal path 40 travels straight through the internal path 40 and is led out from the opening 40a. Each laser beam L1 derived from the opening 40a is reflected toward the light emitting unit 8 by the wavelength selection filter 7 and is applied to the light emitting unit 8.

  According to the light emitting device 102, high-power laser light L1 can be obtained. Therefore, when a plurality of laser lights L1 are irradiated on the same portion of the laser light irradiation surface 8a of the light emitting unit 8, the light emitting device 102 with higher brightness is provided. Can be realized. In addition, when a plurality of laser beams L1 are irradiated to different places on the laser beam irradiation surface 8a of the light emitting unit 8, a light emitting device 102 with a higher luminous flux can be realized.

  For example, in a conventional light emitting device, when a plurality of excitation lights are to be irradiated onto a light emitting unit, in the configuration of Patent Document 1, a plurality of openings for allowing excitation light to pass through a reflector that controls light distribution of fluorescence. Or the diameter of the opening needs to be enlarged. Therefore, the problem that the light projection efficiency by a reflector falls arises.

  In the configuration of Patent Document 2, it is necessary to arrange a plurality of sets of excitation light sources 301 and collimating lenses 305 between the light emitting unit 308 and the convex lens 310. Therefore, the light from the light emission part 308 is interrupted by the plurality of excitation light sources 301 having limited installation flexibility, and there is a problem that the light use efficiency further decreases.

  On the other hand, according to the light emitting device 102, the light from the light emitting unit 8 is not blocked by the laser element 1. In addition, the luminous flux can be easily improved.

(Modification 3)
Further, a projection lens 10 that projects the fluorescence L2 that has passed through the wavelength selection filter 7 may be used.

  FIG. 10 is a cross-sectional view illustrating a configuration of the light emitting device 103 including the projection lens 10. As shown in FIG. 10, the light emitting device 103 includes a projection lens 10 that projects the fluorescence L <b> 2 that has passed through the wavelength selection filter 7.

  The projection lens 10 projects light within a predetermined angle range by refracting the transmitted fluorescence L2. The projection lens 10 is disposed on the side where the wavelength selection filter 7 emits fluorescence L2.

  According to the light emitting device 103, the fluorescence L2 that has passed through the wavelength selection filter 7 can be projected in a predetermined angle range with a simple configuration.

  The wavelength selection filter 7 and the projection lens 10 do not need to be separated from each other. Of course, a multilayer film may be formed on the incident surface of the projection lens 10 and the wavelength selection filter 7 and the projection lens 10 may be integrated.

  In this modification, the configuration using the projection lens 10 has been described as an example. However, the lens need not necessarily be used for projection. In addition to the projection lens 10, a condensing lens, a collimating lens, or a lens group in which a plurality of lenses are combined can be suitably used in combination with the light emitting unit according to the present invention.

(Modification 4)
Further, the shape of the wavelength selection filter 7 is not limited to a flat plate shape, but may be other shapes.

  FIG. 11A and FIG. 11B are cross-sectional views showing the configurations of the light emitting devices 104a and 104b each including a substantially hemispherical wavelength selection filter. FIG. 11A shows a light-emitting device 104a having a paraboloidal wavelength selection filter 7a as a substantially hemispherical wavelength selection filter, and FIG. 11B shows a substantially hemispherical wavelength selection filter. A light emitting device 104b including a spheroidal wavelength selection filter 7b is shown.

  Since the fluorescence L2 is emitted from the light emitting unit 8 in a Lambertian distribution, by using a substantially hemispherical wavelength selection filter such as the rotational paraboloidal wavelength selection filter 7a or the rotational ellipsoidal wavelength selection filter 7b. The fluorescence L2 can be efficiently incident on the wavelength selective filter and emitted to the outside.

  Therefore, according to the light emitting devices 104a and 104b, the utilization efficiency of the fluorescence L2 can be further improved.

  In addition, when the wavelength selection filter 7a having a paraboloidal shape shown in FIG. 11A is used, the light emitting unit 8 is disposed at the focal position, and the laser beam L1 is incident from a direction parallel to the rotation axis direction. By doing so, the configuration of the fourth modification can be suitably implemented. Further, when the spheroidal wavelength selection filter 7b shown in FIG. 11B is used, the light emitting unit 8 is arranged at the position of the second focal point F2, and passes through the position of the first focal point F1. By making the laser beam L1 incident, the configuration of the fourth modification can be suitably implemented.

[Embodiment 2]
The following will describe another embodiment of the present invention with reference to FIGS. In the present embodiment, a light emitting device 105 including a light intensity detection unit 9 that detects the intensity of the laser light L1 will be described.

  For convenience of explanation, members having the same functions as those described in the embodiment are given the same reference numerals, and descriptions thereof are omitted.

<Configuration of Light Emitting Device 105>
FIG. 12 is a cross-sectional view showing the configuration of the light emitting device 105 of the present embodiment. As shown in FIG. 12, the light emitting device 105 includes a laser element 1, an optical fiber 2, and a light emitting unit 35, and the laser element 1 and the light emitting unit 35 are connected by the optical fiber 2.

  The light emitting device 105 includes the dielectric multilayer mirror 65 instead of the mirror 6, and further includes a light intensity detector 9 that detects the intensity of the laser light L1. Mainly different from the device 100.

(Light emitting unit 35)
The light emitting unit 35 emits the fluorescence generated by irradiating the light emitting unit 8 including the phosphor with the laser light L1 emitted from the laser element 1. The light emitting unit 35 includes a heat radiation base (mounting unit) 4, a lens 5, a dielectric multilayer mirror (reflecting mirror) 65, a wavelength selection filter (optical plate) 7, a light emitting unit 8, and a light intensity detection unit 9. .

(Dielectric multilayer mirror 65)
The dielectric multilayer mirror 65 reflects the laser light L1 toward the wavelength selection filter 7. Specifically, the dielectric multilayer film mirror 65 is disposed at a bent portion of the internal path 40 and reflects the laser light L1 introduced from the start end side of the internal path 40 toward the opening 40a. Thereby, the laser beam L1 can be derived from the opening 40a and directed to the wavelength selection filter 7.

The dielectric multilayer mirror 65 transmits part of the laser light L1. The dielectric multilayer mirror 65 can be manufactured by alternately laminating a dielectric material having a high refractive index and a dielectric material having a low refractive index on the substrate. For example, it can be manufactured by using TiO ₂ as a dielectric material having a high refractive index and using SiO ₂ as a dielectric material having a low refractive index, and alternately laminating dozens to dozens of layers.

  In addition, a glass substrate or the like can be used as the substrate, but the substrate is not limited thereto, and any substrate having a light-transmitting property may be used.

  For example, the dielectric multilayer mirror 65 reflects 99% of the irradiated laser light L1 and transmits the remaining 1%.

(Light intensity detector 9)
The light intensity detector 9 detects the intensity of the laser light L1 transmitted through the dielectric multilayer mirror 65. The light intensity detector 9 is disposed inside the heat dissipation base 4 and receives the laser light L1 transmitted through the dielectric multilayer mirror 65. As the light intensity detector 9, a PD (Photo diode) or the like can be used.

  13 is a perspective view showing the configuration of the light intensity detector 9 shown in FIG. 12. FIG. 13 (a) shows the appearance of the light intensity detector 9, and FIG. 13 shows a state in which the cap 91 shown in (a) of FIG. 13 is removed.

  As shown in FIGS. 13A and 13B, the light intensity detector 9 includes a cap 91, a stem 93, and a PD chip 96. The PD chip 96 is mounted on a submount 95 disposed on the stem 93.

  The cap 91 is for sealing the PD chip 96 mounted on the submount 95. A transparent window 92 is incorporated in the cap 91. The PD chip 96 can receive the laser light L1 through the transparent window 92.

  A PD chip 96 is mounted on the surface of the stem 93 via a submount 95. Three lead wires 94a to 94c are arranged on the back surface of the stem 93, and the PD chip 96 is electrically connected to each lead wire by a wire.

  The submount 95 is made of a material (SiC, copper, diamond, aluminum, etc.) having a high thermal conductivity. The submount 95 widens the conduction region of heat generated from the PD chip 96 and efficiently transmits it to the stem 93 and the cap 91, thereby preventing the temperature rise of the PD chip 96 and shortening the life of the PD chip 96. It is provided to deter the conversion. Therefore, the submount 95 is not essential and can be omitted. In this case, the PD chip 96 may be directly mounted on the stem 93 or may be mounted via a general printed board.

  In the light intensity detection unit 9, the height of the cap 91 and the thickness of the submount 95 are adjusted so that the transparent window 92 of the cap 91 is in close contact with the PD chip 96. Thereby, the fluorescence L2 can be efficiently received by the PD chip 96.

  The light intensity detector 9 converts the fluorescence L2 received by the PD chip 96 into an electrical signal corresponding to the intensity of the fluorescence L2, and outputs the electrical signal. Therefore, by monitoring the detection result of the light intensity detector 9, the intensity change of the laser light L1 can be specified.

<Effect of the light emitting device 105>
As described above, the light emitting unit 35 included in the light emitting device 105 of the present embodiment includes the dielectric multilayer film mirror 65 that transmits part of the laser light L1 and the intensity of the laser light L1 that is transmitted by the dielectric multilayer film mirror 65. And a light intensity detection unit 9 for detecting.

  In the light emitting device 105, the light emitting unit 35 further includes a light intensity detection unit 9 that detects the intensity of a part of the laser light L 1 that has passed through the dielectric multilayer mirror 65, so that the detection result of the light intensity detection unit 9 is monitored. By doing so, it is possible to specify the intensity change of the laser beam L1.

  Therefore, according to the light emitting device 105, the laser element 1 can be feedback-controlled based on the detection result of the light intensity detection unit 9 so that the intensity of the laser light L1 is constant. In addition, based on the detection result of the light intensity detector 9, it is possible to detect at an early stage the occurrence of degradation of the laser element 1, disconnection of the optical fiber 2, displacement of the optical fiber 2 and the lens 5, and the like.

  Therefore, according to the light emitting device 105, the light emitting function of the light emitting device 105 can be stabilized, and safety can be improved by detecting the occurrence of a failure at an early stage.

[Embodiment 3]
The following will describe still another embodiment of the present invention with reference to FIGS. In the present embodiment, a light emitting device 106 in which the laser element 1 is disposed inside the heat dissipation base 4 will be described.

  For convenience of explanation, members having the same functions as those described in the embodiment are given the same reference numerals, and descriptions thereof are omitted.

<Configuration of Light Emitting Device 106>
FIG. 14 is a cross-sectional view showing a configuration of the light emitting device 106 of the present embodiment. As shown in FIG. 14, the light emitting device 106 includes a laser element 1, an optical fiber 2, and a light emitting unit 36, and the laser element 1 has a configuration arranged inside the heat dissipation base 4.

  The light emitting device 106 is mainly different from the light emitting device 100 of the above-described embodiment in that the laser element 1 is disposed inside the heat dissipation base 4 and that a MEMS mirror 66 is provided instead of the mirror 6. Yes.

(Light emitting unit 36)
The light emitting unit 36 emits the fluorescence generated by irradiating the light emitting unit 8 including the phosphor with the laser light L1 emitted from the laser element 1. The light emitting unit 36 includes a heat dissipation base (mounting unit) 4, a lens 5, a MEMS mirror (reflecting mirror) 66, a wavelength selection filter (optical plate) 7, and a light emitting unit 8.

  In the light emitting unit 36, the laser element 1 is on the start end side of the internal path 40 of the heat dissipation base 4. Therefore, since the optical fiber 2 is not used, the light emitting device 106 can be reduced in size.

(MEMS mirror 66)
A MEMS (Micro Electro Mechanical System) mirror 66 reflects the laser beam L1 toward the wavelength selection filter 7. Specifically, the MEMS mirror 66 is disposed at a bent portion of the internal path 40, and reflects the laser light L1 emitted from the laser element 1 disposed on the start end side of the internal path 40 toward the opening 40a. Let Thereby, the laser beam L1 can be derived from the opening 40a and directed to the wavelength selection filter 7.

  The MEMS mirror 66 is a drive-type reflecting mirror including a mirror part (reflecting mirror) 66a having a reflecting surface and a driving part (angle changing part) for driving the mirror part 66a. The MEMS mirror 66 can change the angle of the mirror part 66a by operating the drive part 66b. Therefore, by controlling the operation of the driving unit 66b, the incident angle of the laser light L1 with respect to the wavelength selection filter 7 can be changed. As a result, the laser light can be placed at an arbitrary position on the laser light irradiation surface 8a of the light emitting unit 8. L1 can be irradiated.

  Thus, according to the MEMS mirror 66, it is possible to irradiate the laser beam L1 at an arbitrary position on the laser beam irradiation surface 8a of the light emitting unit 8. Therefore, by providing the MEMS mirror 66, the emission center in the light emitting unit 8 can be shifted, so that the emission position of the fluorescence L2 from the light emitting device 100 can be easily changed.

<Effect of the light emitting device 106>
As described above, the light emitting unit 36 included in the light emitting device 106 of the present embodiment includes the MEMS mirror 66 that can change the incident angle of the laser light L1 with respect to the wavelength selection filter 7.

  In the light emitting device 106, the light emitting unit 36 includes the MEMS mirror 66 that can change the incident angle of the laser light L <b> 1 with respect to the wavelength selection filter 7, so that the incident angle of the laser light L <b> 1 with respect to the wavelength selective filter 7 can be changed.

  Therefore, by controlling the operation of the MEMS mirror 66, it is possible to irradiate the laser beam L1 at an arbitrary position on the laser beam irradiation surface 8a of the light emitting unit 8. Therefore, since the emission center in the light emitting unit 8 can be shifted, the emission position of the fluorescence L2 that is emitted through the wavelength selection filter 7 can be changed.

  Therefore, according to the light emitting device 106, for example, when the fluorescence L2 transmitted through the wavelength selection filter 7 is projected by the projection lens 10 or the like, the projection is performed by shifting the irradiation position of the laser light L1 on the laser light irradiation surface 8a. The projection pattern of the fluorescence L2 projected by the lens 10 or the like can be easily changed.

  For example, in a conventional light emitting device, when it is intended to irradiate a laser beam at an arbitrary position on the laser light irradiation surface of the light emitting unit, in the configuration of Patent Document 1, an excitation formed on a reflector that controls the light distribution of fluorescence It is necessary to enlarge the diameter of the opening for allowing light to pass through. Therefore, the problem that the light projection efficiency by a reflector falls arises.

  Further, in the configuration of Patent Document 2, since it is necessary to dispose a driving optical member between the excitation light source 301 and the light emitting unit 308, it is necessary to widen the distance between the light emitting unit 308 and the convex lens 310. For this reason, the light emitted from the light emitting unit 308 with a Lambertian distribution cannot be used by being incident on the convex lens 310 without loss, and there is a problem that the light projecting efficiency is lowered. In addition, since a part of the light emitted from the light emitting unit 308 is blocked by the large-sized drive-type optical member, there arises a problem that the light use efficiency further decreases.

  On the other hand, in the light emitting device 106, since only the wavelength selection filter 7 is disposed between the light emitting unit 8 and the light distribution control member such as the projection lens 10, the projection lens 10 is disposed close to the light emitting unit 8. In addition, the light from the light emitting unit 8 is not blocked by the movable optical member or the like. Therefore, according to the light emitting device 106, it is possible to easily change the projection pattern of the fluorescence L2 projected by the projection lens 10 or the like without reducing the light utilization efficiency.

In addition to the MEMS mirror, a galvano mirror, a polygon mirror, or the like can be suitably used as the drive-type reflecting mirror.
In the present embodiment, the reflecting mirror that reflects the laser light L1 toward the wavelength selection filter 7 is driven, but the present invention is not limited to this configuration. For example, a configuration in which the lens 5 for adjusting the beam diameter of the laser light L1 and the like is driven may be used.

  Furthermore, these drive-type optical members that change the incident angle of the laser light L1 with respect to the wavelength selection filter 7 do not necessarily have to be arranged inside the heat dissipation base 4, and depending on the arrangement position of the laser element 1, etc. It may be arranged outside the heat dissipation base 4.

<Modification>
Next, a modification of the light emitting device 106 will be described with reference to FIGS. 15 and 16. Instead of the MEMS mirror 66, a mirror-6 or a concave mirror 68 may be used.

  FIG. 15 is a cross-sectional view showing a configuration of a light emitting device 107 that includes a mirror 6 instead of the MEMS mirror 66, and FIG. 16 illustrates a configuration of a light emitting device 108 that includes a concave mirror 68 instead of the MEMS mirror 66. It is sectional drawing shown.

  As shown in FIGS. 15 and 16, instead of the MEMS mirror 66, a mirror 6 or a concave mirror 68 may be used. When the concave mirror 68 is used, the concave mirror 68 has a function of reducing the beam diameter of the laser light L1. Therefore, an optimal combination of the lens 5 and the concave mirror 68 is appropriately selected so that the laser beam L1 is irradiated to the light emitting unit 8 with a desired beam diameter. It should be noted that the concave mirror 68 is preferably an off-axis parabolic mirror in that aberrations are reduced.

  According to the light emitting devices 107 and 108, the configuration of the light emitting device can be simplified and the manufacturing cost can be reduced.

[Embodiment 4]
The following will describe still another embodiment of the present invention with reference to FIGS. In the present embodiment, a light emitting device 109 provided with a reflective translucent plate 74 as an optical plate will be described.

  For convenience of explanation, members having the same functions as those described in the embodiment are given the same reference numerals, and descriptions thereof are omitted.

<Configuration of Light Emitting Device 109>
FIG. 17 is a cross-sectional view showing the configuration of the light emitting device 109 of this embodiment. As shown in FIG. 17, the light emitting device 109 includes a laser element 1, an optical fiber 2, and a light emitting unit 37, and the laser element 1 and the light emitting unit 37 are connected by the optical fiber 2.

  The light-emitting device 109 is mainly different from the light-emitting devices 100 to 108 of the above-described embodiment in that a light-transmitting plate (optical plate) 74 is provided instead of the wavelength selection filter 7. Unlike the light emitting devices 100 to 108 described above, the light emitting device 109 emits the spectrum of the laser light L1 to the outside without being removed by the wavelength selection filter 7 and uses it as a part of the illumination light. For example, the wavelength of the laser beam L1 is 365 nm to 490 nm, preferably 390 nm to 410 nm (blue purple) or 440 nm to 480 nm (blue). By irradiating the light emitting unit 8 with the laser light L1 having such a wavelength, the blue-violet or blue laser light L1 and the fluorescence L2 can be mixed to generate white illumination light. In particular, the laser light L1 is preferably visible light because it is used as part of the illumination light without removing the spectrum of the laser light L1. In this case, it can be said that the wavelength range of the laser light L1 is more preferably 440 nm to 480 nm in consideration of the excitation efficiency of the phosphor.

(Light Emitting Unit 37)
The light emitting unit 37 emits the fluorescence L2 and the like generated by irradiating the light emitting unit 8 including the phosphor with the laser light L1 emitted from the laser element 1. The light emitting unit 37 includes a heat radiating base (mounting unit) 4, a lens 5, a mirror (reflecting mirror) 6, a reflective translucent plate 74, and a light emitting unit 8.

  Note that the light emitting unit 37 includes a mirror 6 formed of, for example, an aluminum increased reflection mirror as a reflecting mirror. The dielectric multilayer mirror 65 described above requires strict layer thickness control of the multilayer film and requires manufacturing costs. Therefore, the manufacturing cost of the light emitting unit 37 can be reduced by using the mirror 6.

(Reflective translucent plate 74)
The reflective translucent plate 74 is a translucent plate-like translucent member that is disposed to face the laser light irradiation surface 8 a of the light emitting unit 8. The reflective translucent plate 74 is disposed substantially in parallel with the laser light irradiation surface 8 a of the light emitting unit 8.

  The reflective translucent plate 74 is an optical plate composed of a glass plate 75 and a reflective film (reflective region) 76, and the reflective film 76 is formed on a part of the surface of the glass plate 75 on the light emitting unit 8 side. Yes.

  The glass plate 75 is a plate-like translucent member that serves as a base material for the reflective translucent plate 74. The glass plate 75 transmits the fluorescence L2 emitted from the light emitting unit 8 and the laser light L1 that has not been converted into the fluorescence L2 among the laser light L1 irradiated to the light emitting unit 8.

  In addition, the base material of the reflective translucent board 74 is not limited to the glass board 75, It can comprise from the material which has light transmittances, such as a polycarbonate or an acryl.

  The reflection film 76 reflects the laser light L1 toward the light emitting unit 8. In the present embodiment, the reflective film 76 is formed by depositing a metal material such as aluminum on a part of the surface of the glass plate 75 on the light emitting unit 8 side.

  Here, when the laser light L1 is reflected toward the light emitting unit 8 by the reflective film 76, it is necessary to reduce the fluorescent light L2 blocked by the reflective film 76 in order to efficiently use the fluorescent light L2.

  For this purpose, it is preferable to (1) form the reflective film 76 at a position as far as possible from the light emitting portion 8 in the in-plane direction of the glass plate 75, or (2) make the area of the reflective film 76 as small as possible.

  Regarding (1) above, it is preferable to form the reflective film 76 at a position where the normal line P passing through the center position of the light emitting portion 8 and the normal line Q of the reflective film 76 do not match, and the normal line Q of the reflective film 76 is It is more preferable to form the reflective film 76 at a position that does not overlap the laser light irradiation surface 8a of the light emitting unit 8.

  The center position of the light emitting unit 8 refers to the center of gravity of the surface formed by the contour connecting points where the luminance of the light emitting unit 8 (light source) is 50% of the maximum value. The normal line P passing through the center position of the light emitting unit 8 is a line extending perpendicularly to the laser light irradiation surface 8a from the center of gravity. The normal line Q of the reflective film 76 refers to a line extending perpendicularly to the reflective surface of the reflective film 76 from the position where the laser light L1 is irradiated on the reflective film 76 (that is, incident on the reflective film 76). The half angle of the angle formed by the laser beam L1 and the laser beam L1 reflected by the reflective film 76.)

  Thereby, in the in-plane direction of the glass plate 75, since the reflective film 76 can be formed in the position away from the light emission part 8, the fluorescence L2 obstruct | occluded by the reflective film 76 can be reduced.

  FIGS. 18A to 18C are schematic views for explaining an arrangement example of optical elements having optical surfaces that are not flat. Regarding (2) above, as shown in FIG. 18A, from the emission end portion (excitation light emission end) 2b of the optical fiber 2 that emits the laser light L1 to the laser light irradiation surface 8a of the light emitting portion 8. In the optical path, the optical path length between the exit end 2b and the entrance surface (first optical element surface) 5a of the lens 5 is defined as an optical path length (first optical path length) A, and the exit surface of the lens 5 (second optical element surface). ) When the optical path length between 5b and the laser beam irradiation surface 8a is the optical path length (second optical path length) B (b1 + b2 + b3), the lens 5 may be arranged so that the optical path length A is equal to or shorter than the optical path length B. preferable.

  By making the optical path length A relatively short, the laser beam L1 emitted from the emission end 2b of the optical fiber 2 can be suitably guided to the incident surface 5a of the lens 5 and its beam diameter can be controlled. . Further, by making the optical path length B relatively long, it becomes easy to control the beam diameter of the laser light L1 emitted from the exit surface 5b of the lens 5 and applied to the laser light irradiation surface 8a. The laser beam L1 can be irradiated to the irradiation surface 8a with an optimum beam diameter.

  As described above, by arranging the lens 5 so that the optical path length A is equal to or shorter than the optical path length B, the beam diameter of the laser light L1 can be easily controlled by the optical element having an optical surface that is not a plane. With this setting, the numerical aperture NA of the laser light L1 incident on the laser light irradiation surface 8a can be made equal to or less than the numerical aperture NA of the laser light L1 at the emission end 2b of the optical fiber 2. Since the numerical aperture NA can be reduced, the area of the reflective film 76 can be reduced when the distance from the laser light irradiation surface 8a to the reflective film 76 is the same. In addition, the degree of freedom in design is increased, such as interference of the position of the laser beam L1 and other optical members is less likely to occur.

  Note that, as in the light emitting device 110 shown in FIG. 18B, an optical surface that is not a plane in the optical path from the emission end 2b of the optical fiber 2 that emits the laser light L1 to the laser light irradiation surface 8a of the light emitting unit 8. It is also assumed that a plurality of lenses 5, 15, and 16 having the above are arranged. In this case, the optical path length between the emission end 2b of the optical fiber 2 and the entrance surface 5a that is located on the most upstream side in the optical path and that is not a plane of the lens 5 is the optical path length A, and is most downstream in the optical path. The optical path length between the positioned exit surface (second optical element surface) 16b that is not a plane of the lens 16 and the laser light irradiation surface 8a is the optical path length B (b1 + b2 + b3), and the optical path length A is equal to or shorter than the optical path length B. The lens 5 and the lens 16 may be arranged in the above. In this example, the power of the optical elements installed in the optical path from the emission end 2b of the optical fiber 2 to the laser light irradiation surface 8a of the light emitting unit 8 is set to be positive (condensed) in total. Yes. Do not set a negative (divergence) setting.

  The same applies to the light-emitting device 108 including the wavelength selection filter 7 shown in FIG. In the case of the light emitting device 108, the optical path length between the laser light emitting end (excitation light emitting end) 1 a of the laser element 1 and the incident surface 5 a that is located on the most upstream side in the optical path and that is not a plane of the lens 5 is defined as the optical path. The optical path length between the non-planar reflecting surface (second optical element surface) 68a located on the most downstream side in the optical path and the laser light irradiation surface 8a and the laser light irradiation surface 8a is defined as an optical path length B (b2 + b3). The lens 5 and the concave mirror 68 may be arranged so that the optical path length A is equal to or shorter than the optical path length B. In particular, in the configuration using the concave mirror 68 for condensing the laser light L1, the position of the end portion on the most upstream side in the optical path length B (as compared with the configuration using a lens for condensing the laser light L1 ( The reflection surface 68a) can be installed at a position close to the laser light irradiation surface 8a. Therefore, there is an advantage that the degree of freedom regarding the arrangement of the optical components is increased, such as interference of the positions of the laser beam L1 and other optical members is less likely to occur than when the light is condensed using a lens. As the concave mirror 68, it is desirable to use an off-axis parabolic mirror from the viewpoint of projecting the image of the laser beam emitting end 1a onto the laser beam irradiation surface 8a because aberrations can be suppressed.

<Effect of light emitting device 109>
As described above, the light emitting unit 37 included in the light emitting device 109 of the present embodiment includes the light emitting unit 8 that emits the fluorescence L2 by the irradiation of the laser light L1 and the reflective translucent plate 74 that is disposed to face the light emitting unit 8. The reflective translucent plate 74 includes a reflective film 76 that reflects the laser light L1 emitted from the laser element 1 toward the light emitting unit 8, and emits light when irradiated with the laser light L1 reflected by the reflective film 76. The fluorescence L2 emitted from the unit 8 is transmitted.

  In the light emitting device 109, the light emitting unit 37 includes a reflective translucent plate 74 disposed so as to face the light emitting unit 8, and the reflective translucent plate 74 reflects the laser light L <b> 1 toward the light emitting unit 8. 76. Therefore, the laser light L1 emitted from the laser element 1 is reflected toward the light emitting part 8 by the reflective film 76 of the reflective translucent plate 74, and the light emitting part 8 is irradiated with the laser light L1 to generate fluorescence L2. Can be made. Therefore, it is not necessary to separately arrange an excitation light source or a mirror for irradiating the light emitting unit 8 with the laser light L1 between the light emitting unit 8 and the reflective translucent plate 74.

  Therefore, in the light emitting device 109, it is not necessary to secure a space for arranging an excitation light source or the like between the light emitting unit 8 and the reflective light transmitting plate 74, and the reflective light transmitting plate 74 is disposed close to the light emitting unit 8. Is possible. Therefore, when the fluorescent light L2 that has passed through the reflective translucent plate 74 is projected by a light distribution control member such as a projection lens, the projection lens and the like can be disposed close to the light emitting unit 8, and thus the light emitting unit 8 Fluorescence L2 emitted in a Lambertian distribution can be incident on a projection lens or the like without loss and projected.

  Therefore, according to the present embodiment, the light emitting device 109 with improved light use efficiency can be realized.

  Further, according to the present embodiment, since the laser light L1 can be emitted to the outside together with the fluorescence L2, it can be used as part of the illumination light, so that the light emitting device 109 with high luminance can be realized.

[Embodiment 5]
The following will describe still another embodiment of the present invention with reference to FIGS. In the present embodiment, a light emitting device 111 further including an absorption filter 17 as an optical plate will be described.

  For convenience of explanation, members having the same functions as those described in the embodiment are given the same reference numerals, and descriptions thereof are omitted.

<Configuration of Light Emitting Device 111>
FIG. 19 is a cross-sectional view showing a configuration of the light emitting device 111 of the present embodiment. As shown in FIG. 19, the light emitting device 111 includes a laser element 1, an optical fiber 2, and a light emitting unit 38, and the laser element 1 and the light emitting unit 38 are connected by the optical fiber 2.

  The light emitting device 111 is mainly different from the light emitting device 100 of Embodiment 1 (see FIG. 1) in that it further includes an absorption filter 17 in addition to the wavelength selection filter 7.

(Light emitting unit 38)
The light emitting unit 38 emits the fluorescence generated by irradiating the light emitting unit 8 including the phosphor with the laser light L1 emitted from the laser element 1. The light emitting unit 38 includes a heat dissipation base 4, a lens 5, a mirror 6, a wavelength selection filter (optical plate) 7, an absorption filter (optical plate) 17, and a light emitting unit 8.

(Absorption filter 17)
The absorption filter 17 absorbs light in the wavelength range of the laser light L1 and transmits light having a longer wavelength (fluorescence L2 emitted from the light emitting unit 8). The absorption filter 17 is disposed on the opposite side of the surface of the wavelength selection filter 7 that reflects the laser light L1 (that is, the surface on which the fluorescence L2 is incident).

  Here, as described above, with respect to the operation and effect of the wavelength selection filter 7, by selecting the wavelength of the laser beam L1 and the incident angle to the wavelength selection filter 7 appropriately, the wavelength selection filter 7 can select almost all of the laser beam L1. It is possible to efficiently transmit the fluorescence L2 while being reflected by the filter 7 (see FIG. 3).

  However, not all of the laser light L1 irradiated to the light emitting unit 8 is necessarily converted into fluorescence L2 in the light emitting unit 8, and some of the laser light L1 irradiated to the light emitting unit 8 is part of the laser light L1. A component that is diffusely reflected on the surface of the light emitting unit 8 or a component that is emitted from the light emitting unit 8 as it is without being converted to the fluorescence L2 even when entering the inside of the light emitting unit 8 is generated. Such a stray light component of the laser light L1 is emitted from the light emitting unit 8 in a radiation pattern close to a Lambertian distribution when the portion irradiated with the laser light L1 in the light emitting unit 8 is considered as an emission source. In this case, since the stray light component of the laser light L1 enters the wavelength selection filter 7 at various angles, the stray light component of the laser light L1 incident at a shallow angle with respect to the wavelength selection filter 7 is the wavelength selection filter 7. However, the stray light component of the laser light L1 incident on the wavelength selection filter 7 at a particularly deep angle is not reflected by the wavelength selection filter 7, but passes through the wavelength selection filter 7 and is externally transmitted. Will be released.

  Therefore, the light emitting device 111 further includes an absorption filter 17 in order to absorb a component transmitted through the wavelength selection filter 7 among the stray light components of the laser light L1.

  FIG. 20 is a graph for explaining the wavelength selectivity of the absorption filter 17. In FIG. 20, the horizontal axis indicates the wavelength of incident light, and the vertical axis indicates the transmittance of the light.

  FIG. 20 shows an example of the wavelength selectivity of the absorption filter 17 where the wavelength 418 nm is a cutoff wavelength and light having a wavelength shorter than 418 nm is absorbed while light having a wavelength longer than 418 nm is transmitted. Unlike the wavelength selectivity of the wavelength selection filter 7, the wavelength selectivity of the absorption filter 17 does not depend on the incident angle. Therefore, the stray light component of the laser light L1 can be absorbed regardless of the incident angle of the stray light component of the laser light L1.

  As described above, in the light emitting device 111, the wavelength selection filter 7 which is a reflective filter that transmits the fluorescence L2 and reflects the laser light L1, and the absorption filter 17 that transmits the fluorescence L2 and absorbs the laser light L1 are two sheets. By using it together, it is possible to block the laser light L1 including the stray light component. That is, the wavelength selection filter 7 plays a role of selectively reflecting the laser light L1, and the absorption filter 17 causes stray light in the laser light L1 to be reflected from the wavelength selection filter 7 without being reflected by the wavelength selection filter 7. The transmitted laser beam L1 can be absorbed.

  Such an absorption filter 17 is obtained by dispersing a light-absorbing substance in a transparent member such as glass. For example, the one disclosed in Japanese Patent No. 5142139 can be used.

(Optical fiber 2)
21A is a plan view showing the emission end 2b of the optical fiber 2 of the present embodiment, and FIG. 21B is a plan view showing the light emitting unit 8. As shown in FIG. As shown in FIG. 21A, in this embodiment, a multimode fiber in which the shape of the core 21 at the emission end 2b is a quadrangle is used as the optical fiber 2. The optical fiber 2 has a structure in which an inner core 21 is covered with a clad 22 having a refractive index lower than that of the core 21 and the clad 22 is covered with a coating layer 23. The size of the core 21 can be a square or a rectangle of several hundred μm square such as 100 μm to 800 μm square, for example. The laser beam L1 emitted from the laser element 1 is coupled to the incident end 2a of the optical fiber 2 having the rectangular core 21.

  The light emitted from the laser device 1 having a Gaussian light intensity distribution is input to the optical fiber 2 that is a multimode fiber having a square core 21, so that the light distribution at the emission end 2 b of the optical fiber 2 is increased. A rectangular near-field image that is substantially uniform can be obtained.

  In the present embodiment, as the lens 5, an imaging lens is used that forms an image by enlarging the shape of the rectangular core 21 at the emission end 2 b of the optical fiber 2 on the laser light irradiation surface 8 a of the light emitting unit 8. Thus, as shown in FIG. 21B, when a near-field image at the emission end 2 b of the optical fiber 2 is formed on the laser light irradiation surface 8 a of the light emitting unit 8 by the lens 5, Since the laser beam L1 is irradiated onto the rectangular laser beam irradiation region 8b on the laser beam irradiation surface 8a, the light emitting unit 8 can emit light uniformly in a rectangular shape.

  In addition, each side ad of the square core 21 shown to (a) of FIG. 21 is each side a of the laser beam irradiation area | region 8b shown to (b) of FIG. The image is formed as “˜d”.

  In the present embodiment, as the projection lens 10, by using a lens that projects light so that the light emission shape of the light emitting unit 8 forms an image in the distance, the light emission shape of the light emitting unit 8 that uniformly emits light in a rectangular shape as described above. It can be projected far away.

  Therefore, by projecting so that the straight line portion of the rectangular projection pattern is horizontal, it is one of the low-beam (passing light) cut-off lines for automotive headlamps that require a high linear contrast that extends horizontally. The part can be suitably projected. That is, the configuration of the present embodiment can be particularly suitably used as a low beam of an automobile headlamp.

<Configuration of Light Emitting Device 111>
As described above, in the light emitting unit 38 included in the light emitting device 111 of the present embodiment, the laser beam L1 of the wavelength selection filter 7 is reflected in addition to the wavelength selection filter 7 that reflects the laser beam L1 and transmits the fluorescence L2. An absorption filter 17 that selectively absorbs the laser light L1 is further included on the surface opposite to the surface to be formed.

  Thus, by using together the wavelength selection filter 7 which is a reflective filter that transmits the fluorescence L2 and reflects the laser light L1, and the absorption filter 17 that transmits the fluorescence L2 and absorbs the laser light L1, The laser light L1 including the stray light component can be blocked.

  Therefore, according to the present embodiment, it is possible to realize the light emitting device 111 that can suitably prevent the stray light component of the laser light L1 that has not been converted into the fluorescence L2 from leaking to the outside.

<Modification>
Next, a modification of the light emitting unit 8 will be described with reference to FIG. FIG. 22A and FIG. 22B are plan views for explaining a modification of the light emitting unit 8. In the above description, as shown in FIG. 22A, the light emitting unit 8 having the laser light irradiation surface 8a larger than the rectangular laser light irradiation region 8b is used, and the laser light irradiation surface 8a of the light emitting unit 8 is formed. A configuration in which the light emitting unit 8 emits light uniformly in a rectangular shape by irradiating a part of the laser beam L1 is shown.

  However, as shown in FIG. 22B, the area / shape of the laser light irradiation region 8b and the area / shape of the laser light irradiation surface 8a of the light emitting portion 8 may be matched. In this case, since the contrast of light and darkness at the end of the light emitting unit 8 becomes very large, the light and dark contrast of the straight line portion of the rectangular projection pattern projected by the light emitting device 111 can be increased.

  Therefore, this modification can be suitably applied when it is desired to project a projection pattern with a strong contrast between light and dark.

  Note that the same effect can be obtained even when the light emitting portion 8 having a smaller area / shape of the laser light irradiation surface 8a than the area / shape of the laser light irradiation region 8b is used.

[Embodiment 6]
The following will describe still another embodiment of the present invention with reference to FIGS. In the present embodiment, a light emitting device 112 in which the light emitting unit 8 is inclined in the light emitting unit 39 will be described.

  For convenience of explanation, members having the same functions as those described in the embodiment are given the same reference numerals, and descriptions thereof are omitted.

<Configuration of Light Emitting Device 112>
FIG. 23 is a cross-sectional view showing a configuration of the light emitting device 112 of the present embodiment. As shown in FIG. 23, the light emitting device 112 includes a laser element 1, an optical fiber 2, and a light emitting unit 39, and the laser element 1 and the light emitting unit 39 are connected by the optical fiber 2.

  The light emitting device 112 is mainly different from the light emitting device 109 of the fourth embodiment (see FIG. 17) in that the laser light irradiation surface 8a of the light emitting unit 8 is disposed to be inclined with respect to the reflective film 76.

(Light emitting unit 39)
The light emitting unit 39 emits the fluorescence L2 and the like generated by irradiating the light emitting unit 8 including the phosphor with the laser light L1 emitted from the laser element 1. The light emitting unit 39 includes a heat radiating base 4, a lens 5, a mirror 6, a reflective translucent plate 74, and a light emitting unit 8.

  In the light emitting unit 39 of the present embodiment, the light emitting unit 8 is inclined so that the laser light irradiation surface 8a of the light emitting unit 8 faces a direction different from the arrangement direction of the reflective film 76 (that is, the reflective film 76 and the laser light irradiation). The surface 8a is not parallel). Thereby, the irradiation amount to the reflection film 76 of the fluorescence L2 emitted from the light emitting unit 8 can be reduced, and the fluorescence L2 blocked by the reflection film 76 can be reduced.

  In the fourth embodiment, the fluorescent film L <b> 2 blocked by the reflective film 76 can be reduced by forming the reflective film 76 at a position away from the light emitting unit 8 in the in-plane direction of the glass plate 75. Explained. On the other hand, in the present embodiment, as a configuration for reducing the fluorescence L <b> 2 blocked by the reflective film 76, the light emitting unit 8 is tilted so that the laser light irradiation surface 8 a faces a direction different from the direction in which the reflective film 76 is disposed. The configuration is shown. That is, the fluorescence L2 is emitted most strongly in the normal direction of the laser light irradiation surface 8a of the light emitting unit 8, but in this embodiment, the normal line of the laser light irradiation surface 8a is inclined in a direction away from the reflection film 76. Yes. For this reason, the amount of fluorescence L2 emitted from the light emitting unit 8 to the reflective film 76 is reduced, so that the fluorescence L2 blocked by the reflective film 76 can be greatly reduced.

  Furthermore, in this embodiment, it is preferable to provide the side wall part A formed by making the glass plate 75 bend | fold about 90 degrees at the edge part of the glass plate 75 located in the normal line direction of the laser beam irradiation surface 8a. By forming the side wall portion A, it is possible to increase the extraction efficiency of the fluorescence L2 in the light emitting device 112.

  FIG. 24 is a cross-sectional view showing a modification of the side wall portion A shown in FIG. The shape of the side wall portion A of the glass plate 75 is not particularly limited. For example, as shown in FIG. 24, a side wall B formed by bending a glass plate 75 into a smooth curved surface may be provided on the glass plate 75. In the side wall portion A, unnecessary light scattering or the like may occur at a corner portion bent by approximately 90 °. However, the side wall portion B is preferable because such light scattering or the like can be suppressed.

  In the present embodiment, the wavelength of the laser light L1 may be in the wavelength range of 365 nm to 490 nm as in the fourth embodiment. In particular, it is preferable to use blue laser light L1 of 440 nm to 480 nm, and this embodiment can be suitably applied in a configuration in which laser light L1 is mixed with fluorescence L2 from the light emitting unit 8 to obtain white light.

<Effect of the light emitting device 112>
As described above, in the light emitting unit 39 included in the light emitting device 112 of the present embodiment, the light emitting unit 8 applies laser light to the reflective film 78 so that the fluorescent film L2 emitted from the light emitting unit 8 is not irradiated onto the reflective film 78. The irradiation surface 8a is inclined.

  Therefore, according to the present embodiment, it is possible to reduce the fluorescence L2 that is blocked by the reflective film 76, and thus it is possible to realize the light emitting device 112 that improves the extraction efficiency of the fluorescence L2.

  The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope shown in the claims, and embodiments obtained by appropriately combining technical means disclosed in different embodiments. Is also included in the technical scope of the present invention. Furthermore, a new technical feature can be formed by combining the technical means disclosed in each embodiment.

[Summary]
A light-emitting unit according to aspect 1 of the present invention includes a light-emitting unit that emits fluorescence (L2) by irradiation with excitation light (laser light L1), and an optical plate (wavelength selection filter 7) disposed to face the light-emitting unit. The optical plate reflects the excitation light emitted from an excitation light source (laser element 1) toward the light emitting unit, and emits the fluorescence emitted from the light emitting unit by irradiation of the excitation light. It is characterized by transmitting.

  In the above configuration, the light emitting unit includes an optical plate arranged to face the light emitting unit, the optical plate reflects the excitation light toward the light emitting unit, and is irradiated with the excitation light from the light emitting unit. Transmits emitted fluorescence. That is, the optical plate has wavelength selectivity that reflects excitation light and transmits fluorescence.

  Therefore, the excitation light emitted from the excitation light source is reflected toward the light emitting part by the optical plate, so that the light emitting part can be irradiated with the excitation light to generate fluorescence. Therefore, it is not necessary to arrange an excitation light source or a mirror for irradiating the light emitting unit with excitation light between the light emitting unit and the optical plate.

  Therefore, in the above configuration, since a part of the fluorescence emitted from the light emitting unit is not blocked by the excitation light source or the like disposed between the light emitting unit and the optical plate, the fluorescence can be used efficiently. Can do.

  Further, in the above configuration, since it is not necessary to secure a space for arranging the excitation light source and the like between the light emitting unit and the optical plate, the optical plate can be arranged close to the light emitting unit. Therefore, when the fluorescent light that has passed through the optical plate is projected by a light distribution control member such as a projection lens, the projection lens and the like can be disposed close to the light emitting unit, and thus emitted from the light emitting unit in a Lambertian distribution. Can be incident on a projection lens or the like without loss.

  Therefore, according to said structure, the light emission unit which improved the utilization efficiency of light is realizable.

  In the light emitting unit according to aspect 2 of the present invention, in the above aspect 1, the optical plate is disposed so as to face an excitation light irradiation surface that is a surface of the light emitting unit irradiated with the excitation light. The unit may emit the fluorescence mainly from the excitation light irradiation surface.

  In said structure, a light emission part emits fluorescence mainly from an excitation light irradiation surface, and the transparent plate is arrange | positioned facing this excitation light irradiation surface. Therefore, the fluorescence emitted from the excitation light irradiation surface can be efficiently incident on the optical plate and emitted to the outside.

  Therefore, according to said structure, the utilization efficiency of light can be improved more.

  In the light emitting unit according to aspect 3 of the present invention, in the above aspect 1 or 2, the optical plate may include a reflective filter that reflects the excitation light and transmits the fluorescence.

  According to said structure, the optical board of this invention is suitably implement | achieved using the reflection type filter which permeate | transmits the light (fluorescence) of a specific wavelength range, and reflects the light (excitation light) of the other wavelength range. can do.

  In the light emitting unit according to aspect 4 of the present invention, in the above aspect 3, the optical plate absorbs the excitation light selectively on the surface of the reflective filter opposite to the surface that reflects the excitation light. A mold filter may be further included.

  In the above configuration, the optical plate further includes an absorptive filter that transmits light (fluorescence) in a specific wavelength range and absorbs light (excitation light) in other wavelength ranges. Even when the stray light component of the excitation light that has not been converted into fluorescence passes through the reflective filter, the stray light component of the transmitted excitation light can be absorbed by the absorption filter.

  Therefore, according to said structure, it can prevent more reliably that the stray-light component of excitation light leaks outside.

  In the light emitting unit according to aspect 5 of the present invention, in the above aspect 3 or 4, the wavelength of the excitation light may be not less than 390 nm and not more than 410 nm.

  According to said structure, a blue-violet or blue-violet laser beam can be utilized as excitation light.

  In the light emitting unit according to aspect 6 of the present invention, in the above aspect 1 or 2, the optical plate (reflective translucent plate 74) includes a translucent member (glass plate 75) that transmits the excitation light and the fluorescence, and And a reflective film that is provided on a part of the translucent member and reflects the excitation light toward the light emitting part.

  In the above configuration, the optical plate irradiates the light emitting unit with the excitation light by reflecting the excitation light emitted from the excitation light source toward the light emitting unit by the reflection film provided on a part of the light transmitting member. Fluorescence can be generated. Further, the optical plate can emit the fluorescence emitted from the light emitting part to the outside by transmitting the light transmitting member.

  Therefore, according to said structure, the optical board of this invention is suitably realizable with the translucent member and the reflecting film provided in a part of this translucent member.

  In the light emitting unit according to aspect 7 of the present invention, in the above aspect 6, the light emitting unit is arranged to be inclined with respect to the reflective film so that the fluorescence emitted from the light emitting unit is not irradiated onto the reflective film. May be.

  According to said structure, since the fluorescence interrupted | blocked by a reflecting film can be reduced, the taking-out efficiency of the fluorescence in a light emission unit can be improved.

  In the light emitting unit according to aspect 8 of the present invention, in the above aspect 6 or 7, the wavelength of the excitation light may be not less than 440 nm and not more than 480 nm.

  According to said structure, the excitation light which is visible light can be used as a part of illumination light with fluorescence, and the fall of the excitation efficiency of the light emission part by excitation light can be suppressed.

  In the light emitting unit according to Aspect 9 of the present invention, in any one of Aspects 1 to 8, the light emitting unit further includes a mounting portion (heat dissipating base) having a mounting surface on which the light emitting portion is mounted. An internal path for guiding the excitation light; one end of the internal path forms an opening in the mounting surface; and the optical plate emits the excitation light derived from the opening. May be reflected toward the light emitting unit.

  In the above configuration, the optical plate reflects the excitation light derived from the opening formed on the mounting surface on which the light emitting unit is placed toward the light emitting unit. It becomes easy to arrange the excitation light source.

  Therefore, according to said structure, an excitation light source can be suitably arrange | positioned in the position which does not block the fluorescence emitted from a light emission part.

  In the light emitting unit according to aspect 10 of the present invention, in the above aspect 9, the light emitting unit further includes a reflecting mirror (mirror 6) that reflects the excitation light emitted from the excitation light source toward the optical plate, The excitation light disposed in the internal path and introduced from the other end side of the internal path may be reflected toward the opening.

  In the above configuration, since the excitation light introduced from the other end side of the internal path is reflected toward the opening by the reflection mirror, the excitation light is incident on the optical plate by changing the installation angle (tilt) of the reflection mirror. The angle can be adjusted.

  Therefore, according to said structure, compared with the case where the installation angle of excitation light source itself is changed, adjustment of the incident angle of excitation light with respect to a transparent plate becomes easy.

  The light emitting unit according to aspect 11 of the present invention may further include an angle changing unit (driving unit 66b) that changes the angle of the reflecting mirror (mirror unit 66a) in the above aspect 10.

  In said structure, an excitation light can be irradiated to the arbitrary positions of a light emission part by controlling an angle change part and changing the angle of a reflective mirror. Therefore, it is possible to shift the light emission center in the light emitting unit, so that the emission position of the fluorescence emitted through the optical plate can be changed.

  Therefore, according to the above configuration, for example, when projecting fluorescence transmitted through the optical plate by a light distribution control member such as a projection lens, the irradiation position of excitation light in the light emitting unit is shifted by controlling the angle changing unit. Thus, the position of the fluorescent light projection pattern projected by the projection lens or the like can be easily changed.

  In the light emitting unit according to aspect 12 of the present invention, in the above aspect 10 or 11, the reflecting mirror (dielectric multilayer mirror 65) transmits part of the excitation light, and the reflecting mirror transmits the light. Further, a detection unit (light intensity detection unit 9) for detecting the intensity of the excitation light may be further provided.

  In the above configuration, since the light emitting unit further includes a detection unit that detects the intensity of a part of the excitation light that has passed through the reflecting mirror, the intensity change of the excitation light is identified by monitoring the detection result of the detection unit. be able to.

  Therefore, in the above configuration, the excitation light source can be feedback-controlled so that the intensity of the excitation light is constant based on the detection result of the detection unit. In addition, based on the detection result of the detection unit, it is possible to detect at an early stage occurrence of deterioration of the excitation light source, displacement of the optical member, breakage, and the like.

  Therefore, according to said structure, while being able to stabilize the light emission function of a light emission unit, the safety | security of a light emission unit can be improved by discovering generation | occurrence | production of malfunctions, such as an excitation light source, at an early stage.

  In the light emitting unit according to Aspect 13 of the present invention, in any one of Aspects 9 to 12, the excitation light emitted from the excitation light source disposed outside the mounting portion is used as the other end side of the internal path. May further include a light guide (optical fiber 2) introduced into the internal path.

  According to said structure, since the excitation light source is arrange | positioned outside the mounting part, a light emitting unit can be reduced in size. Moreover, since the space | interval of an excitation light source and a light emission part can be enlarged, it can avoid that a light emission part deteriorates with the heat which generate | occur | produced in the excitation light source.

  Moreover, according to said structure, since the excitation light radiate | emitted from the excitation light source arrange | positioned outside the mounting part is introduce | transduced into an internal path | route by a light guide part, the freedom degree of the arrangement position of an excitation light source is raised. be able to.

  In the light emitting unit according to Aspect 14 of the present invention, in the Aspect 13, the light guide section may include an optical fiber having a quadrangular core at the emission end that emits the excitation light.

  In the configuration described above, the light emitted from the optical fiber having a quadrangular core at the emission end is imaged on the light emitting part, so that the light emitting part can emit light in a rectangular shape.

  Therefore, according to the above configuration, a rectangular light projection pattern can be projected by projecting the light emission shape of the light emitting unit far away as it is, and thus, for example, a low beam (passing lamp) of an automotive headlamp. ) Can be suitably used as part of the cut-off line.

  In the light emitting unit according to Aspect 15 of the present invention, in any one of Aspects 1 to 14, the optical plate (wavelength selection filters 7a and 7b) may have a substantially hemispherical shape opened to the light emitting part side.

  In the above configuration, since the optical plate has a substantially hemispherical shape opened toward the light emitting unit, fluorescence emitted from the light emitting unit with a Lambertian distribution can be efficiently incident on the optical plate and emitted to the outside. .

  Therefore, according to said structure, the utilization efficiency of light can further be improved.

  In the light emitting unit according to Aspect 16 of the present invention, in any one of Aspects 15 described above, the optical plate (wavelength selection filters 7a and 7b) may have a paraboloid shape or a spheroidal shape.

  According to said structure, the substantially hemispherical optical plate which can make the fluorescence discharge | released by the Lambertian distribution from a light emission part efficiently inject into an optical plate, and can discharge | release it outside can be obtained suitably.

  The light-emitting device which concerns on aspect 17 of this invention is equipped with the light-emitting unit in any one of the said aspects 1-16, and the said excitation light source, It is characterized by the above-mentioned.

  According to said structure, the light-emitting device which improved the utilization efficiency of light is realizable.

  A lighting device according to aspect 18 of the present invention includes the light-emitting device according to aspect 17 described above.

  According to said structure, the illuminating device which improved the utilization efficiency of light is realizable.

  A vehicle headlamp according to an aspect 19 of the present invention includes the light emitting device according to the aspect 17 described above.

  According to said structure, the vehicle headlamp which improved the utilization efficiency of light is realizable.

[Supplement]
The present invention can also be expressed as follows. That is, in the light emitting unit according to Aspect 20 of the present invention, in any one of Aspects 1 to 3, the optical plate is an excitation light that has not been converted to the fluorescence among the excitation light irradiated to the light emitting section. Is preferably reflected toward the light emitting portion.

  Most of the excitation light irradiated to the light emitting part is absorbed by the phosphor and converted into fluorescence. However, there may be a case where a part of the excitation light is not converted for some reason.

  According to the above configuration, even in such a case, the excitation light that has not been converted to fluorescence is reflected by the optical plate to the light emitting unit side, so that the excitation light can be prevented from leaking outside.

  A light emitting unit according to an aspect 21 of the present invention includes a light emitting unit that emits fluorescence when irradiated with excitation light, and an optical plate (reflective translucent plate 74) disposed to face the light emitting unit. And a reflection region (reflective film 76) that reflects the excitation light emitted from the excitation light source toward the light emitting unit, and is emitted from the light emitting unit by irradiation of the excitation light reflected by the reflection region. The fluorescent light is transmitted.

  In the above configuration, the light emitting unit includes an optical plate disposed to face the light emitting unit, and the optical plate has a reflection region that reflects the excitation light toward the light emitting unit. Therefore, the excitation light emitted from the excitation light source is reflected toward the light emitting part by the reflection region of the optical plate, so that the excitation light can be irradiated to the light emitting part to generate fluorescence. Therefore, it is not necessary to separately arrange an excitation light source and a mirror for irradiating the light emitting unit with excitation light between the light emitting unit and the optical plate.

  Therefore, in the above configuration, it is not necessary to secure a space for arranging an excitation light source or the like between the light emitting unit and the optical plate, and the optical plate can be arranged close to the light emitting unit. Therefore, when the fluorescent light that has passed through the optical plate is projected by a light distribution control member such as a projection lens, the projection lens and the like can be disposed close to the light emitting unit, and thus emitted from the light emitting unit in a Lambertian distribution. Can be incident on a projection lens or the like without loss.

  Therefore, according to said structure, the light emission unit which improved the utilization efficiency of light is realizable. Further, according to the above configuration, since the excitation light can be emitted to the outside together with the fluorescence and used as part of the illumination light, a high-luminance light emitting device can be realized.

  In the light emitting unit according to aspect 22 of the present invention, in the aspect 21, the excitation light that is the surface of the light emitting unit irradiated with the excitation light from the excitation light emitting end of the excitation light source that emits the excitation light. In the optical path to the irradiation surface, the optical path length between the excitation light exit end and the first optical element surface which is not the most upstream plane in the optical path is defined as the first optical path length, and the optical path length is positioned on the most downstream side in the optical path. When the second optical path length is defined as the optical path length between the second optical element surface that is not a flat surface and the excitation light irradiation surface, the first optical path length is preferably equal to or shorter than the second optical path length.

  In the above configuration, by making the first optical path length relatively short, it becomes possible to appropriately guide the excitation light emitted from the excitation light emitting end to the first optical element surface and control the beam diameter. . Further, by making the second optical path length relatively long, it becomes easy to control the beam diameter of the excitation light emitted from the second optical element surface and applied to the excitation light irradiation surface. Can be irradiated with an optimum beam diameter.

  Therefore, according to said structure, control of the beam diameter of the excitation light by an optical element becomes easy, and excitation light can be irradiated with the optimal beam diameter with respect to the excitation light irradiation surface.

  The present invention can be applied to a light-emitting device and a lighting device, particularly a headlamp for a vehicle or the like, and can improve the light use efficiency.

1 Laser element (excitation light source)
1a Laser light emitting end (excitation light emitting end)
2 Optical fiber (light guide)
2b Output end (excitation light output end)
3 Light emitting unit 4 Heat dissipation base (mounting part)
4a Placement surface 5a Incident surface (first optical element surface)
6 Mirror (Reflector)
7 Wavelength selection filter (optical plate, reflection type filter)
7a Wavelength selection filter (optical plate, reflection type filter)
7b Wavelength selection filter (optical plate, reflection type filter)
8 Light emitting part 9 Light intensity detection part (detection part)
8a Laser light irradiation surface (excitation light irradiation surface)
16b Output surface (second optical element surface)
17 Absorption filter (optical plate)
21 Core 35-39 Light emitting unit 40 Internal path 40a Opening 65 Dielectric multilayer mirror (reflecting mirror)
66 MEMS mirror (reflector)
66a Mirror part (reflecting mirror)
66b Drive unit (angle changing unit)
68 Concave mirror
68a Reflective surface (second optical element surface)
74 Reflective translucent plate (optical plate)
75 Glass plate (Translucent plate)
76 Reflective film (reflection area)
100-112 Light Emitting Device 200 Headlamp (Vehicle Headlamp / Lighting Device)
A Optical path length (first optical path length)
B Optical path length (second optical path length)
F1 first focus F2 second focus

Claims (19)

A light-emitting part that emits fluorescence when irradiated with excitation light; and
An optical plate disposed to face the light emitting unit,
The optical plate reflects the excitation light emitted from the excitation light source toward the light emitting unit, and transmits the fluorescence emitted from the light emitting unit by irradiation of the excitation light. unit. The optical plate is disposed to face an excitation light irradiation surface that is a surface of the light emitting unit irradiated with the excitation light,
The light emitting unit according to claim 1, wherein the light emitting unit emits the fluorescence mainly from the excitation light irradiation surface.   The light emitting unit according to claim 1, wherein the optical plate includes a reflective filter that reflects the excitation light and transmits the fluorescence.   4. The optical plate according to claim 3, further comprising an absorption filter that selectively absorbs the excitation light on a surface opposite to a surface of the reflective filter that reflects the excitation light. Light emitting unit.   The light emitting unit according to claim 3 or 4, wherein the wavelength of the excitation light is 390 nm or more and 410 nm or less.   The optical plate includes a translucent member that transmits the excitation light and the fluorescence, and a reflective film that is provided on a part of the translucent member and reflects the excitation light toward the light emitting unit. The light emitting unit according to claim 1, wherein the light emitting unit is a light emitting unit.   The light emitting unit according to claim 6, wherein the light emitting unit is disposed to be inclined with respect to the reflective film so that the fluorescent light emitted from the light emitting unit is not irradiated on the reflective film.   The light emitting unit according to claim 6 or 7, wherein the wavelength of the excitation light is 440 nm or more and 480 nm or less. It further comprises a mounting unit having a mounting surface for mounting the light emitting unit,
The placement unit has an internal path for guiding the excitation light,
One end of the internal path forms an opening on the placement surface,
The light emitting unit according to claim 1, wherein the optical plate reflects the excitation light derived from the opening toward the light emitting unit. A reflection mirror that reflects the excitation light emitted from the excitation light source toward the optical plate;
10. The light emitting device according to claim 9, wherein the reflecting mirror is disposed in the internal path and reflects the excitation light introduced from the other end side of the internal path toward the opening. unit.   The light emitting unit according to claim 10, further comprising an angle changing unit that changes an angle of the reflecting mirror.   The said reflecting mirror transmits a part of said excitation light, It further has a detection part which detects the intensity | strength of the said excitation light which the said reflecting mirror permeate | transmitted. Light emitting unit.   The light guide part which introduces the excitation light radiate | emitted from the said excitation light source arrange | positioned outside the said mounting part from the other end side of the said internal path | route to this internal path | route is further provided. The light emitting unit according to any one of 1 to 12.   The light-emitting unit according to claim 13, wherein the light guide unit includes an optical fiber having a quadrangular core shape at an excitation light emitting end that emits the excitation light.   The light emitting unit according to any one of claims 1 to 14, wherein the optical plate has a substantially hemispherical shape opened to the light emitting unit side.   The light emitting unit according to claim 15, wherein the optical plate has a paraboloid shape or a spheroid shape. The light emitting unit according to any one of claims 1 to 16,
The excitation light source;
A light emitting device comprising:   An illumination device comprising the light-emitting device according to claim 17.   A vehicle headlamp comprising the light-emitting device according to claim 17.

Images