JP6748905B2 - Light emitting device - Google Patents

Description

The present disclosure relates to a light emitting device, and particularly to a light emitting device having a photoluminescent layer.

Optical devices such as lighting fixtures, displays, and projectors are required to emit light in a necessary direction in many applications. Photoluminescent materials used in fluorescent lamps, white LEDs and the like emit isotropic light. Therefore, such a material is used together with optical components such as a reflector and a lens in order to emit light only in a specific direction. For example, Patent Document 1 discloses an illumination system in which directivity is secured by using a light distribution plate and an auxiliary reflection plate.

JP, 2010-231941, A

When optical components such as a reflector and a lens are arranged in the optical device, the size of the optical device itself increases in order to secure the space. Therefore, it is advantageous that the optical device can be downsized if these optical components can be downsized as much as possible.

A light emitting device according to an embodiment of the present disclosure is an excitation light source, a light emitting element arranged on an optical path of excitation light from the excitation light source, and a first light emitting element arranged on an optical path of light emitted from the light emitting element. And a condenser lens. The light-emitting element includes a photoluminescent layer that receives the excitation light and emits light having _a wavelength of λ _{a in} the air, _a light-transmissive layer disposed in proximity to the photoluminescent layer, the photoluminescent layer and the light-transmissive layer. The surface structure is formed on at least one surface of the optical layer and includes at least one of a plurality of convex portions and a plurality of concave portions. The surface structure limits the directional angle of the light having _a wavelength λ _{a in} the air emitted by the photoluminescent layer.

The above general or specific aspects may be implemented in any element, device, system, method, or any combination thereof.

According to an embodiment of the present disclosure, a light emitting device that is easy to miniaturize is provided.

FIG. 3 is a perspective view showing a configuration of a light emitting device according to an embodiment. FIG. 1B is a partial cross-sectional view of the light emitting device shown in FIG. 1A. FIG. 11 is a perspective view showing a configuration of a light emitting device according to another embodiment. FIG. 2 is a partial cross-sectional view of the light emitting device shown in FIG. 1C. It is a figure which shows the result of having calculated the enhancement degree of the light radiate|emitted to the front direction, changing each emission wavelength and the height of a periodic structure. 6 is a graph illustrating the conditions of m=1 and m=3 in Expression (10). It is a figure which shows the result of having calculated the enhancement degree of the light output to the front direction, changing the light emission wavelength and the thickness t of the photo-luminescence layer. It is a figure which shows the result of having calculated the electric field distribution of the mode guided in an x direction, when thickness t=238nm. It is a figure which shows the result of having calculated the electric field distribution of the mode guided in an x direction, when thickness t=539 nm. It is a figure which shows the result of having calculated the electric field distribution of the mode guided in an x direction, when thickness t=300 nm. It is a figure which shows the result of having calculated the enhancement degree of light in the case where the polarization of light is TE mode which has an electric field component perpendicular to ay direction on the same conditions as the calculation of FIG. It is a top view showing an example of a two-dimensional periodic structure. It is a figure which shows the result of having performed the calculation similar to FIG. 2 regarding a two-dimensional periodic structure. It is a figure which shows the result of having calculated the enhancement degree of the light output to the front direction by changing the light emission wavelength and the refractive index of a periodic structure. It is a figure which shows the result at the time of making the film thickness of a photo-luminescence layer into 1000 nm on the conditions similar to FIG. It is a figure which shows the result of having calculated the enhancement degree of the light output to the front direction by changing the emission wavelength and the height of the periodic structure. It is a figure which shows the calculation result when the refractive index of a periodic structure is set to _np =2.0 on the conditions similar to FIG. It is a figure which shows the result of having performed the same calculation as the calculation shown in FIG. 9 on the assumption that the polarization of light is a TE mode having an electric field component perpendicular to the y direction. It is a figure which shows the result at the time of changing the refractive index _nwav of a photo-luminescence layer into 1.5 on the conditions similar to the calculation shown in FIG. It is a figure which shows the calculation result at the time of providing the photoluminescent layer and periodic structure of the same conditions as the calculation shown in FIG. 2 on the transparent substrate whose refractive index is 1.5. 9 is a graph illustrating the condition of Expression (15). It is a figure which shows the structural example of the light-emitting device 200 provided with the light emitting element 100 shown in FIGS. 1A and 1B, and the light source 180 which makes excitation light inject into the photo-luminescence layer 110. It is a diagram showing a one-dimensional periodic structure having the x direction of the period p _x. x-direction period p _x, illustrates a two-dimensional periodic structure having a period p _y in the y direction. It is a figure which shows the wavelength dependence of the light absorption rate in the structure of FIG. 17A. It is a figure which shows the wavelength dependence of the light absorption rate in the structure of FIG. 17B. It is a figure which shows an example of a two-dimensional periodic structure. It is a figure which shows the other example of a two-dimensional periodic structure. It is a figure which shows the modification which formed the periodic structure on the transparent substrate. It is a figure which shows the other modification which formed the periodic structure on the transparent substrate. It is a figure which shows the result of having calculated the enhancement degree of the light output to the front direction by changing the light emission wavelength and the period of a periodic structure in the structure of FIG. 19A. It is a figure showing the composition which mixed a plurality of powdery light emitting elements. FIG. 3 is a plan view showing an example in which a plurality of periodic structures having different periods are two-dimensionally arranged on a photoluminescent layer. It is a figure which shows an example of the light emitting element which has the structure in which the some photo-luminescence layer 110 by which the uneven structure was formed in the surface was laminated|stacked. 3 is a cross-sectional view showing a configuration example in which a protective layer 150 is provided between the photoluminescent layer 110 and the surface structure 120. FIG. It is a figure which shows the example which formed the surface structure 120 by processing a part of photoluminescent layer 110. FIG. It is a figure which shows the cross-sectional TEM image of the photo-luminescence layer formed on the glass substrate which has a periodic structure. It is a graph which shows the result of having measured the spectrum in the front direction of the emitted light of the light emitting element manufactured as a trial. It is a figure which shows the condition which rotates the light emitting element which radiate|emits the linearly polarized light of TM mode about the axis|shaft parallel to the line direction of a one-dimensional periodic structure as an axis of rotation. It is a graph which shows the result of having measured the angle dependence of the emitted light when rotating the prototype light emitting element as shown in FIG. 27A. It is a graph which shows the result of having calculated the angle dependence of the emitted light when rotating the prototype light emitting element as shown in FIG. 27A. It is a figure which shows the condition which rotates the light emitting element which radiates|emits the linearly polarized light of TE mode about the axis|shaft parallel to the line direction of a one-dimensional periodic structure as an axis of rotation. FIG. 28 is a graph showing the results of measuring the angle dependence of emitted light when a prototype light emitting device is rotated as shown in FIG. 27D. It is a graph which shows the result of having calculated the angle dependence of the emitted light when rotating the prototype light emitting element as shown in FIG. 27D. It is a figure which shows the condition which rotates the light emitting element which radiates|emits the linearly polarized light of TE mode about the axis|shaft perpendicular to the line direction of a one-dimensional periodic structure as a rotation axis. It is a graph which shows the result of having measured the angle dependence of the emitted light when rotating the prototype light emitting element as shown in FIG. 28A. It is a graph which shows the result of having calculated the angle dependence of the emitted light when rotating the prototype light emitting element as shown in FIG. 28A. It is a figure which shows the condition which rotates the light emitting element which radiate|emits the linearly polarized light of TM mode about the axis|shaft perpendicular to the line direction of a one-dimensional periodic structure as a rotation axis. It is a graph which shows the result of having measured the angle dependence of the emitted light when rotating the prototype light emitting element as shown in FIG. 28D. It is a graph which shows the result of having calculated the angle dependence of the emitted light when rotating the prototype light emitting element as shown in FIG. 28D. It is a graph which shows the result of having measured the angle dependence of the emitted light (wavelength 610nm) of the light emitting element produced as a trial. It is a perspective view which shows an example of a slab type|mold waveguide typically. FIG. 6 is a schematic diagram for explaining the relationship between the wavelength and the emission direction of light that undergoes a light emission enhancing effect in a light emitting element having a surface structure 120 on the photoluminescence layer 110. FIG. 4 is a schematic plan view showing an example of a configuration in which a plurality of periodic structures having different wavelengths showing an emission enhancement effect are arranged. It is a typical top view showing the example of the composition which arranged a plurality of periodic structures from which the direction where the convex part of a one-dimensional periodic structure extends differs. It is a typical top view showing the example of the composition which arranged a plurality of two-dimensional periodic structures. It is a typical sectional view of a light emitting element provided with a microlens. FIG. 3 is a schematic cross-sectional view of a light emitting element having a plurality of photoluminescent layers having different emission wavelengths. FIG. 6 is a schematic cross-sectional view of another light emitting element having a plurality of photoluminescent layers having different emission wavelengths. FIG. 3 is a schematic diagram showing an exemplary configuration of a light emitting device according to an embodiment of the present disclosure. FIG. 3 is a schematic diagram for explaining coupling efficiency between a light emitting element 100 and a condenser lens 202 in a light emitting device according to an embodiment of the present disclosure. FIG. 8 is a schematic diagram for explaining coupling efficiency between a phosphor 512 and a condenser lens 202 in a light emitting device 510 of a comparative example. FIG. 16 is a schematic diagram showing another modification of the light emitting device according to the embodiment of the present disclosure. FIG. 13 is a schematic diagram showing still another modification of the light emitting device according to the embodiment of the present disclosure. FIG. 13 is a schematic diagram showing still another modification of the light emitting device according to the embodiment of the present disclosure. FIG. 13 is a schematic diagram showing still another modification of the light emitting device according to the embodiment of the present disclosure. FIG. 3 is an external view illustrating an example of a projection device according to an aspect of the present disclosure. FIG. 43 is a schematic diagram showing an example of an optical system in the projection device 2300 shown in FIG. 42. FIG. 43 is a block diagram showing an outline of an example of a configuration of the projection device 2300 shown in FIG. 42. It is a schematic diagram which shows a mode that an image is formed by the light reflected by the MEMS mirror 2322A. It is a schematic diagram which shows the other example of the optical system which can switch the wavelength of the light radiate|emitted from the optical fiber 2250. 16 is a schematic diagram showing another example of the optical system in the projection device 2300. FIG. FIG. 47 is a block diagram showing an outline of an example of a configuration corresponding to the optical system shown in FIG. 46. It is a schematic diagram for demonstrating the optical coupling between a light source and an optical fiber. 9 is a graph schematically showing the relationship between the light emitting area S of the light source 2280 and the amount A of light introduced into the optical fiber 2250. FIG. 6 is an external view of a projection device of a comparative example, which has a light projecting unit in which all the optical components of the image forming optical system are housed. FIG. 51 is a schematic diagram showing a configuration for forming an image, which is arranged inside a light projecting unit 2510 of the projection device 2500 shown in FIG. 50. FIG. 28 is a schematic diagram showing still another example of the optical system in the projection device 2300. FIG. 28 is a schematic diagram showing still another example of the optical system in the projection device 2300. It is sectional drawing which shows typically the example of the light-emitting device provided with the light emitting element 100' and the support body 3540 which supports the light emitting element 100'. FIG. 54B is a plan view of the light-emitting device shown in FIG. 54A as seen from above. It is a figure which shows the example which has the structure 3590 of taking in the light which guide|induces excitation light into the photo-luminescence layer 110 efficiently. It is sectional drawing which shows typically the other example of the light-emitting device provided with the light emitting element 100' and the support body 3540 which supports the light emitting element 100'. FIG. 55B is a plan view of the light-emitting device shown in FIG. 55A as seen from above. It is sectional drawing which shows typically the further another example of the light-emitting device provided with the light emitting element 100' and the support body 3540 which supports the light emitting element 100'. FIG. 56B is a plan view of the light-emitting device shown in FIG. 56A as seen from above. It is sectional drawing which shows typically the further another example of the light-emitting device provided with the light emitting element 100' and the support body 3540 which supports the light emitting element 100'. FIG. 57B is a plan view of the light-emitting device shown in FIG. 57A as seen from above. It is sectional drawing which shows typically the further another example of the light-emitting device provided with the light emitting element 100' and the support body 3540 which supports the light emitting element 100'. It is the top view which looked at the light-emitting device shown to FIG. 58A from the upper direction. It is sectional drawing which shows typically the further another example of the light-emitting device provided with the light emitting element 100' and the support body 3540 which supports the light emitting element 100'. FIG. 59B is a plan view of the light-emitting device shown in FIG. 59A as seen from above. It is sectional drawing which shows typically the further another example of the light-emitting device provided with the light emitting element 100' and the support body 3540 which supports the light emitting element 100'. FIG. 60B is a plan view of the light-emitting device shown in FIG. 60A as seen from above. It is sectional drawing which shows typically the further another example of the light-emitting device provided with the light emitting element 100' and the support body 3540 which supports the light emitting element 100'. FIG. 61B is a plan view of the light-emitting device shown in FIG. 61A as seen from above. It is sectional drawing which shows typically the further another example of the light-emitting device provided with the light emitting element 100' and the support body 3540 which supports the light emitting element 100'. FIG. 62B is a plan view of the light-emitting device shown in FIG. 62A as seen from above. It is sectional drawing which shows typically the further another example of the light-emitting device provided with the light emitting element 100' and the support body 3540 which supports the light emitting element 100'. FIG. 63B is a plan view of the light-emitting device shown in FIG. 63A as seen from above. It is sectional drawing which shows typically the further another example of the light-emitting device provided with the light emitting element 100' and the support body 3540 which supports the light emitting element 100'. FIG. 64B is a plan view of the light-emitting device shown in FIG. 64A as seen from above. It is sectional drawing which shows typically the further another example of the light-emitting device provided with the light emitting element 100' and the support body 3540 which supports the light emitting element 100'. FIG. 65B is a plan view of the light-emitting device shown in FIG. 65A as seen from above. It is sectional drawing which shows typically the further another example of the light-emitting device provided with the light emitting element 100' and the support body 3540 which supports the light emitting element 100'. FIG. 66B is a plan view of the light-emitting device shown in FIG. 66A as seen from above. It is sectional drawing which shows typically the further another example of the light-emitting device provided with the light emitting element 100' and the support body 3540 which supports the light emitting element 100'. FIG. 67B is a plan view of the light-emitting device shown in FIG. 67A as seen from above. It is sectional drawing which shows typically the further another example of the light-emitting device provided with the light emitting element 100' and the support body 3540 which supports the light emitting element 100'. FIG. 69B is a plan view of the light-emitting device shown in FIG. 68A as seen from above. It is sectional drawing which shows typically the further another example of the light-emitting device provided with the light emitting element 100' and the support body 3540 which supports the light emitting element 100'. FIG. 69B is a plan view of the light-emitting device shown in FIG. 69A as seen from above. It is sectional drawing which shows typically the further another example of the light-emitting device provided with the light emitting element 100' and the support body 3540 which supports the light emitting element 100'. FIG. 70B is a plan view of the light-emitting device shown in FIG. 70A as seen from above. It is sectional drawing which shows typically the further another example of the light-emitting device provided with the light emitting element 100' and the support body 3540 which supports the light emitting element 100'. FIG. 71B is a plan view of the light-emitting device shown in FIG. 71A as seen from above. It is sectional drawing which shows typically the further another example of the light-emitting device provided with the light emitting element 100' and the support body 3540 which supports the light emitting element 100'. FIG. 72B is a plan view of the light-emitting device shown in FIG. 72A as seen from above. It is sectional drawing which shows typically the further another example of the light-emitting device provided with the light emitting element 100' and the support body 3540 which supports the light emitting element 100'. FIG. 73B is a plan view of the light-emitting device shown in FIG. 73A as seen from above. It is sectional drawing which shows typically the further another example of the light-emitting device provided with the light emitting element 100' and the support body 3540 which supports the light emitting element 100'. FIG. 74B is a plan view of the light-emitting device shown in FIG. 74A as seen from above. It is sectional drawing which shows typically the further another example of the light-emitting device provided with the light emitting element 100' and the support body 3540 which supports the light emitting element 100'. FIG. 75B is a plan view of the light-emitting device shown in FIG. 75A as seen from above. It is a top view which shows typically the further another example of the light-emitting device provided with the light emitting element 100' and the support body 3540 which supports the light emitting element 100'. It is a top view which shows typically the further another example of the light-emitting device provided with the light emitting element 100' and the support body 3540 which supports the light emitting element 100'. It is a figure which shows schematic structure of the light-emitting device which has a reflector. It is a figure which shows schematic structure of the light-emitting device which does not have a reflector. It is a figure which shows the other example of the light-emitting device which has a reflector. It is a figure which shows the example of the light-emitting device which has a support body. It is a figure which shows the other example of the light-emitting device which has a support body. It is a figure which shows the further another example of the light-emitting device which has a support body. It is a figure which shows the example of the light-emitting device with which the excitation light source and the light emitting element were supported by the support body. It is a figure which shows the size of the illuminating device using the conventional light emitting element. It is a figure which shows the size of the illuminating device using the light emitting element in embodiment of this indication. It is a figure which shows the size of the illuminating device using the light emitting element and reflector in embodiment of this indication. It is a figure which shows the example of the light-emitting device which synthesize|combines the light from a some light source. It is a figure which shows the further detailed structural example of the light-emitting device which synthesize|combines the light from a some light source. It is a figure which shows the example of a structure which the additional light source 5500 functions also as excitation light. It is a figure which shows the further another example of the light-emitting device which synthesize|combines the light from a some light source. It is a figure which shows the further another example of the light-emitting device which synthesize|combines the light from a some light source. It is a figure which shows the further another example of the light-emitting device which synthesize|combines the light from a some light source. It is a figure which shows the further another example of the light-emitting device which synthesize|combines the light from a some light source. It is a figure which shows the further another example of the light-emitting device which synthesize|combines the light from a some light source. It is a figure which shows the further another example of the light-emitting device which synthesize|combines the light from a some light source. It is a figure which shows the further another example of the light-emitting device which synthesize|combines the light from a some light source. It is a figure which shows the further another example of the light-emitting device which synthesize|combines the light from a some light source. It is a figure which shows the example of application to a household fiber lighting system. It is a figure which shows the example of the light-emitting device which synthesize|combines the light of the several wavelength range which is emitted in a different direction from a light emitting element. It is a figure which shows the detail of the structural example of the light-emitting device which synthesize|combines the light of a several wavelength range. It is a figure which shows the example of the light-emitting device which obtains white light by synthesize|combining the light of three specific wavelengths. It is a figure which shows the example which the 1st light radiate|emitted from the light emitting element 100' in a 1st direction and the 2nd light radiate|emitted in a 2nd direction are each introduce|transduced into different optical fiber 6530a, 6530b. .. It is a figure which shows the other example of the light-emitting device which connected the some optical fiber. It is a figure which shows the example which used the structure in which the some light emitting element 100r, 100g, 100b was tiled instead of the light emitting element 100' in the structure of FIG. FIG. 100 is a diagram showing an example in which a part of the light emitted from the excitation light source 180 is further used in the configuration shown in FIG. 97. It is a figure which shows the example which changed the position of the excitation light source 180 in FIG. FIG. 100 is a diagram showing an example in which a part of the light emitted from the excitation light source 180 is further used in the configuration shown in FIG. 100. It is a figure which shows the example of application to a household fiber lighting system. It is a typical sectional view showing an example of a surface structure which has at least one of a plurality of convex parts and a plurality of concave parts.

[1. Outline of Embodiments of Present Disclosure]
The present disclosure includes a light emitting element, a light emitting device, and a projection device described in the following items.

[Item 1]
Excitation light source,
A light emitting element arranged on the optical path of the excitation light from the excitation light source,
A first condenser lens disposed on the optical path of the light emitted from the light emitting element,
The light emitting element is
A photoluminescence layer which receives excitation light and emits light having _a wavelength in air of λ _a ;
A translucent layer disposed in proximity to the photoluminescent layer,
Formed on the surface of at least one of the photoluminescent layer and the translucent layer, and having a surface structure including at least one of a plurality of convex portions and a plurality of concave portions,
The surface structure is _a light emitting device that limits the directivity angle of light having _a wavelength λ _{a in} the air emitted by the photoluminescent layer.

[Item 2]
Excitation light source,
A light emitting element arranged on the optical path of the excitation light from the excitation light source,
A first condenser lens disposed on the optical path of the light emitted from the light emitting element,
The light emitting element is
A transparent layer,
A surface structure formed on the surface of the light-transmitting layer and including at least one of a plurality of convex portions and a plurality of concave portions,
A photoluminescence layer which is arranged close to the surface structure and which receives excitation light and emits light having _a wavelength in the air of λ _a ;
The surface structure is _a light emitting device that limits the directivity angle of light having _a wavelength λ _{a in} the air emitted by the photoluminescent layer.

[Item 3]
Excitation light source,
A light emitting element arranged on the optical path of the excitation light from the excitation light source,
A first condenser lens disposed on the optical path of the light emitted from the light emitting element,
The light emitting element is
A photoluminescence layer which receives excitation light and emits light having _a wavelength in air of λ _a ;
A translucent layer having a refractive index higher than that of the photoluminescent layer,
Formed on the surface of the light-transmitting layer, and having a surface structure including at least one of a plurality of convex portions and a plurality of concave portions,
The surface structure is _a light emitting device that limits the directivity angle of light having _a wavelength λ _{a in} the air emitted by the photoluminescent layer.

[Item 4]
Excitation light source,
A light emitting element arranged on the optical path of the excitation light from the excitation light source,
A first condenser lens disposed on the optical path of the light emitted from the light emitting element,
The light emitting element is
A photoluminescence layer which receives excitation light and emits light having _a wavelength in air of λ _a ;
Formed on the surface of the photoluminescent layer, having a surface structure including at least one of a plurality of convex portions and a plurality of concave portions,
The surface structure is _a light emitting device that limits the directivity angle of light having _a wavelength λ _{a in} the air emitted by the photoluminescent layer.

[Item 5]
The surface structure has at least one periodic structure,
When the period of at least one periodic structure and _{p a, λ a / n wav} -a < relationship p _a <λ _a is satisfied, the light emitting device as described in any one of 1 to 4.

[Item 6]
Item 6. The light-emitting device according to any one of Items 1 to 5, which has a collimator lens arranged between the light-emitting element and the first condenser lens.

[Item 7]
7. The light-emitting device according to any one of Items 1 to 6, which has an optical fiber connecting portion at a position where the light emitted from the first condenser lens is incident.

[Item 8]
Item 8. The light emitting device according to any one of Items 1 to 7, which has a second condenser lens disposed between the excitation light source and the light emitting element.

[Item 9]
Item 8. The light emitting device according to any one of Items 1 to 7, which has a collimating lens arranged between the excitation light source and the light emitting element.

[Item 10]
Item 9. The light emitting device according to item 8, having a collimating lens arranged between the excitation light source and the second condenser lens.

[Item 11]
A light emitting element,
A support for supporting the light emitting element,
Equipped with
The light emitting element is
A photoluminescence layer which receives excitation light and emits light having _a wavelength in air of λ _a ;
A translucent layer disposed in proximity to the photoluminescent layer,
Formed on the surface of at least one of the photoluminescent layer and the translucent layer, and having a surface structure including at least one of a plurality of convex portions and a plurality of concave portions,
The surface structure limits the directivity angle of light having _a wavelength λ _{a in} the air emitted by the photoluminescence layer,
The support contacts the other part of the light emitting element to support the light emitting element so that a part of the light emitting element is exposed.
Light emitting device.

[Item 12]
The support is in contact with the photoluminescent layer,
The thermal conductivity of the support is higher than the thermal conductivity of the photoluminescent layer,
Item 11. The light emitting device according to item 11.

[Item 13]
Item 13. The light-emitting device according to item 11 or 12, wherein the support surrounds the periphery of the photoluminescent layer.

[Item 14]
An excitation light source for emitting excitation light is further provided,
The excitation light source is arranged so that the excitation light is incident on the exposed portion of the light emitting device, and the excitation light is incident on the photoluminescent layer at an angle inclined with respect to the normal direction of the photoluminescent layer,
14. The light emitting device according to any one of items 11 to 13.

[Item 15]
The support is
A support portion in contact with the light emitting element,
An opening that spreads from the support to the excitation light source side, and an opening having a side surface that is inclined with respect to the normal direction of the photoluminescence layer,
15. The light-emitting device according to item 14, which comprises:

[Item 16]
16. The light emitting device according to item 15, wherein the excitation light source is arranged so that the excitation light is incident on the light emitting element along the side surface of the opening.

[Item 17]
The support is
A support portion in contact with the light emitting element,
An opening extending from the support along the optical path of the excitation light,
15. The light-emitting device according to any one of items 11 to 14, which comprises:

[Item 18]
Item _18. The light-emitting device according to any one of Items 11 to 17, wherein _a light-transmitting layer has a refractive index n _ta for light having _a wavelength of λ _{a in} air that is smaller than _a refractive index n _{wav-a of the} photoluminescent layer for light.

[Item 19]
19. The light-emitting device according to any one of items 11 to 18, wherein the intensity of light having _a wavelength λ _a in the air is maximized in the first direction predetermined by the surface structure.

[Item 20]
20. The light-emitting device according to item 19, wherein the surface structure limits a directivity angle of light having _a wavelength λ _a in air with respect to the first direction to less than 15°.

[Item 21]
The surface structure is such that light with _a wavelength of λ _{a in} the air is emitted most strongly in the normal direction of the photoluminescence layer, and excitation light with a wavelength of λ _ex propagates inside the photoluminescence layer. It is configured to be emitted most strongly in the direction of the angle θ _out from the normal direction of
The excitation light source is arranged so that the excitation light enters the light emitting element at an incident angle θ _out ,
21. The light emitting device according to any one of items 11 to 20.

[Item 22]
A light emitting element,
A support for supporting the light emitting element,
Equipped with
The light emitting element is
A transparent layer,
A surface structure formed on the surface of the light-transmitting layer and including at least one of a plurality of convex portions and a plurality of concave portions,
A photoluminescence layer which is arranged close to the surface structure and which receives excitation light and emits light having _a wavelength in the air of λ _a ;
The surface structure limits the directivity angle of light having _a wavelength λ _{a in} the air emitted by the photoluminescence layer,
The support contacts the other part of the light emitting element to support the light emitting element so that a part of the light emitting element is exposed.
Light emitting device.

[Item 23]
A light emitting element,
A support for supporting the light emitting element,
Equipped with
The light emitting element is
A photoluminescence layer which receives excitation light and emits light having _a wavelength in air of λ _a ;
A translucent layer having a refractive index higher than that of the photoluminescent layer,
Formed on the surface of the light-transmitting layer, and having a surface structure including at least one of a plurality of convex portions and a plurality of concave portions,
The surface structure limits the directivity angle of light having _a wavelength λ _{a in} the air emitted by the photoluminescence layer,
The support contacts the other part of the light emitting element to support the light emitting element so that a part of the light emitting element is exposed.
Light emitting device.

[Item 24]
A light emitting element,
A support for supporting the light emitting element,
Equipped with
The light emitting element is
A photoluminescence layer which receives excitation light and emits light having _a wavelength in air of λ _a ;
Formed on the surface of the photoluminescent layer, having a surface structure including at least one of a plurality of convex portions and a plurality of concave portions,
The surface structure limits the directivity angle of light having _a wavelength λ _{a in} the air emitted by the photoluminescence layer,
The support contacts the other part of the light emitting element to support the light emitting element so that a part of the light emitting element is exposed.
Light emitting device.

[Item 25]
Excitation light source,
A light emitting element,
A reflector provided on the optical path of the excitation light emitted from the excitation light source and reflecting the excitation light to the light emitting element,
The light emitting element is
A photoluminescence layer which receives excitation light and emits light having _a wavelength in air of λ _a ;
A translucent layer disposed in proximity to the photoluminescent layer,
Formed on the surface of at least one of the photoluminescent layer and the translucent layer, and having a surface structure including at least one of a plurality of convex portions and a plurality of concave portions,
The surface structure limits the directivity angle of light having _a wavelength λ _{a in} the air emitted by the photoluminescent layer,
Light emitting device.

[Item 26]
26. The light emitting device according to any one of Items 1 to 3 and 25, wherein the surface structure limits a directivity angle of light having _a wavelength λ _{a in} the air emitted by the photoluminescence layer to less than 15°.

[Item 27]
The surface structure has a quasi-guided mode that maximizes the intensity of light having _a wavelength of λ _{a in} the air emitted from the photoluminescence layer in the first direction that is predetermined by the surface structure, inside the photoluminescence layer. Item 27. The light-emitting device according to item 25 or 26, which is formed in the above.

[Item 28]
28. The light emitting device according to any one of Items 25 to 27, wherein the reflector reflects the excitation light so that the excitation light is incident on the photoluminescent layer at an angle inclined with respect to a direction perpendicular to the main surface of the photoluminescent layer. ..

[Item 29]
Further comprising a support for supporting the light emitting element,
The reflector is provided on a part of the support,
29. The light emitting device according to any one of items 25 to 28.

[Item 30]
30. The light emitting device according to item 29, wherein the support further supports an excitation light source.

[Item 31]
31. The light emitting device according to any one of Items 25 to 30, wherein the reflector has an angle adjusting mechanism that changes a reflection angle of the excitation light.

[Item 32]
Excitation light source,
A light emitting element disposed on the optical path of the excitation light emitted from the excitation light source,
The light emitting element is
A photoluminescence layer which receives excitation light and emits light having _a wavelength in air of λ _a ;
A translucent layer disposed in proximity to the photoluminescent layer,
Formed on the surface of at least one of the photoluminescent layer and the translucent layer, and having a surface structure including at least one of a plurality of convex portions and a plurality of concave portions,
The surface structure limits the directivity angle of light having _a wavelength λ _{a in} the air emitted by the photoluminescent layer,
Light emitting device.

[Item 33]
33. The light emitting device according to item 32, further comprising a support that supports the excitation light source and the light emitting element.

[Item 34]
34. The light emitting device according to any one of items 25 to 33, further comprising a collimator lens arranged on an optical path between the excitation light source and the light emitting element.

[Item 35]
Let D _int be the distance between two adjacent convex portions or two adjacent concave portions in the surface structure, and let n _wav-a be the refractive index of the photoluminescent layer for light with _a wavelength λ _a in the air, λ _a 35. The light-emitting device according to any one of Items 1 to 3, 11 to 21, and 25 to 34, wherein _a relationship of /n _wav-a <D _int <λ _a is established.

[Item 36]
The surface structure has at least one periodic structure,
_Letting n _wav-a be the refractive index of the photoluminescence layer for light having _a wavelength of λ _{a in} air, and p _a be the period of at least one periodic structure, λ _a /n _wav-a <p _a <λ _a Item 36. The light-emitting device according to any one of Items 11 to 21 and 25 to 35, wherein the relationship holds.

[Item 37]
A photoluminescence layer which receives excitation light and emits light having _a wavelength in air of λ _a ;
A translucent layer disposed in proximity to the photoluminescent layer,
Formed on the surface of at least one of the photoluminescent layer and the translucent layer, and having a surface structure including at least one of a plurality of convex portions and a plurality of concave portions,
The surface structure limits the directivity angle of light having _a wavelength λ _{a in} the air emitted by the photoluminescent layer,
Light emitting element.

[Item 38]
Excitation light source,
A light emitting element,
A reflector provided on the optical path of the excitation light emitted from the excitation light source and reflecting the excitation light to the light emitting element,
The light emitting element is
A transparent layer,
A surface structure formed on the surface of the light-transmitting layer and including at least one of a plurality of convex portions and a plurality of concave portions,
A photoluminescence layer which is arranged close to the surface structure and which receives excitation light and emits light having _a wavelength in the air of λ _a ;
The surface structure limits the directivity angle of light having _a wavelength λ _{a in} the air emitted by the photoluminescent layer,
Light emitting device.

[Item 39]
Excitation light source,
A light emitting element,
A reflector provided on the optical path of the excitation light emitted from the excitation light source and reflecting the excitation light to the light emitting element,
The light emitting element is
A photoluminescence layer which receives excitation light and emits light having _a wavelength in air of λ _a ;
A translucent layer having a refractive index higher than that of the photoluminescent layer,
Formed on the surface of the light-transmitting layer, and having a surface structure including at least one of a plurality of convex portions and a plurality of concave portions,
The surface structure limits the directivity angle of light having _a wavelength λ _{a in} the air emitted by the photoluminescent layer,
Light emitting device.

[Item 40]
Excitation light source,
A light emitting element,
A reflector provided on the optical path of the excitation light emitted from the excitation light source and reflecting the excitation light to the light emitting element,
The light emitting element is
A photoluminescence layer which receives excitation light and emits light having _a wavelength in air of λ _a ;
Formed on the surface of the photoluminescent layer, having a surface structure including at least one of a plurality of convex portions and a plurality of concave portions,
The surface structure limits the directivity angle of light having _a wavelength λ _{a in} the air emitted by the photoluminescent layer,
Light emitting device.

[Item 41]
A transparent layer,
A surface structure formed on the surface of the light-transmitting layer and including at least one of a plurality of convex portions and a plurality of concave portions,
A photoluminescence layer which is arranged close to the surface structure and which receives excitation light and emits light having _a wavelength in the air of λ _a ;
The surface structure limits the directivity angle of light having _a wavelength λ _{a in} the air emitted by the photoluminescent layer,
Light emitting element.

[Item 42]
A photoluminescence layer which receives excitation light and emits light having _a wavelength in air of λ _a ;
A translucent layer having a refractive index higher than that of the photoluminescent layer,
Formed on the surface of the light-transmitting layer, and having a surface structure including at least one of a plurality of convex portions and a plurality of concave portions,
The surface structure limits the directivity angle of light having _a wavelength λ _{a in} the air emitted by the photoluminescent layer,
Light emitting element.

[Item 43]
A photoluminescence layer which receives excitation light and emits light having _a wavelength in air of λ _a ;
Formed on the surface of the photoluminescent layer, having a surface structure including at least one of a plurality of convex portions and a plurality of concave portions,
The surface structure limits the directivity angle of light having _a wavelength λ _{a in} the air emitted by the photoluminescent layer,
Light emitting element.

[Item 44]
The light-emitting element according to any one of items 41 to 43,
An excitation light source that emits excitation light that is introduced into the photoluminescent layer in the light emitting element,
A light emitting device comprising.

[Item 45]
Let D _int be the distance between two adjacent convex portions or two adjacent concave portions in the surface structure, and let n _wav-a be the refractive index of the photoluminescent layer for light with _a wavelength λ _a in the air, λ _a Item 44. The light-emitting device according to item 44, wherein _a relationship of /n _wav-a <D _int <λ _a is established.

[Item 46]
The surface structure has at least one periodic structure,
_Letting n _wav-a be the refractive index of the photoluminescence layer for light having _a wavelength of λ _{a in} air, and p _a be the period of at least one periodic structure, λ _a /n _wav-a <p _a <λ _a Item 45. The light-emitting device according to Item 45, wherein the relationship holds.

[Item 47]
A photoluminescent layer that emits light including first light having _a wavelength of λ _a in air and second light having a wavelength of λ _{b in} air;
A translucent layer disposed in proximity to the photoluminescent layer,
A first structure having a surface structure formed on at least one surface of a photoluminescent layer and a translucent layer and including at least one of a plurality of convex portions and a plurality of concave portions, wherein the wavelength in air emitted by the photoluminescent layer is λ _a Of the first light is maximized in a first direction predetermined by at least one of the plurality of protrusions and the plurality of recesses, and the intensity of the second light is A surface structure that maximizes in a second direction different from the one direction;
An optical system for combining the first light and the second light,
A light emitting device comprising.

[Item 48]
Item 48. The light emitting device according to item 47, wherein the optical system combines the first light emitted in the first direction and the second light emitted in the second direction.

[Item 49]
49. The light emitting device according to item 47 or 48, further comprising an optical fiber that takes in the light combined by the optical system from one end and emits the light from the other end.

[Item 50]
Any one of Items 47 to 49, further comprising a light source that makes third light including excitation light that excites the photoluminescent material in the photoluminescent layer to generate first light and second light enter the photoluminescent layer. The light-emitting device according to.

[Item 51]
51. The light emitting device according to item 50, wherein the optical system combines a part of the third light emitted from the light source and transmitted through the photoluminescence layer, the first light, and the second light.

[Item 52]
A photoluminescent layer that emits light including first light having _a wavelength of λ _a in air and second light having a wavelength of λ _{b in} air;
A translucent layer disposed in proximity to the photoluminescent layer,
A first structure having a surface structure formed on at least one surface of a photoluminescent layer and a translucent layer and including at least one of a plurality of convex portions and a plurality of concave portions, wherein the wavelength in air emitted by the photoluminescent layer is λ _a Of the first light is maximized in a first direction predetermined by at least one of the plurality of protrusions and the plurality of recesses, and the intensity of the second light is A surface structure that maximizes in a second direction different from the one direction of light;
A first optical system for introducing the first light into the first optical fiber;
A second optical system for introducing the second light into the second optical fiber;
A light emitting device comprising.

[Item 53]
The first optical system introduces the first light emitted in the first direction into the first optical fiber,
The second optical system introduces the second light emitted in the second direction into the second optical fiber,
Item 52. The light-emitting device according to Item 52.

[Item 54]
Further comprising a first optical fiber and a second optical fiber,
The first optical fiber and the second optical fiber are connected to combine the first light and the second light at a connection point,
The light-emitting device according to item 52 or 53.

[Item 55]
Any of items 52 to 54, further comprising a light source that causes third light including excitation light that excites the photoluminescent material in the photoluminescent layer to generate the first light and the second light to enter the photoluminescent layer. The light-emitting device according to.

[Item 56]
Item 56. The light-emitting device according to item 55, further comprising a third optical system that introduces a part of the third light emitted from the light source and transmitted through the photoluminescent layer into the third optical fiber.

[Item 57]
Further comprising first to third optical fibers,
57. A light emitting device according to item 56, wherein the first to third optical fibers are connected and combine the first to third lights at the connection points.

[Item 58]
Let D _int be the distance between the centers of two adjacent convex portions or the centers of two adjacent concave portions in the surface structure, and let n _{wav be} the refractive index of the photoluminescent layer for the first light having _a wavelength λ _{a in} air. The light-emitting device according to any one of Items 47 to 57, wherein the relationship of λ _a /n _wav-a <D _int <λ _a is satisfied when _−a .

[Item 59]
The first surface structure has at least one periodic structure,
When the refractive index of the first photoluminescent layer for light having _a wavelength of λ _{a in} air is n _wav-a and the period of at least one periodic structure is p _a , λ _a /n _wav-a <p _a <λ relationship _a holds, the light-emitting device according to any one of items 47 58.

[Item 60]
Item 60. The light emitting device according to any one of Items 1 to 3, 11 to 23, 25 to 39, 41, 42, 47 to 59, wherein the photoluminescent layer and the translucent layer are in contact with each other.

[Item 61]
A transparent layer,
A surface structure formed on the surface of the light-transmitting layer and including at least one of a plurality of convex portions and a plurality of concave portions,
A photoluminescent layer disposed adjacent to the surface structure and emitting light including first light having _a wavelength λ _a in air and second light having a wavelength λ _{b in} air;
An optical system for combining the first light and the second light,
Equipped with
The surface structure limits the directivity angle of the first light having _a wavelength λ _a in the air emitted by the photoluminescent layer, and predetermines the intensity of the first light by at least one of the plurality of convex portions and the plurality of concave portions. In a first direction, the intensity of the second light is maximized in a second direction different from the direction of the first light,
Light emitting device.

[Item 62]
A photoluminescent layer that emits light including first light having _a wavelength of λ _a in air and second light having a wavelength of λ _{b in} air;
A translucent layer having a refractive index higher than that of the photoluminescent layer,
A surface structure that is formed on the surface of the translucent layer and includes at least one of a plurality of convex portions and a plurality of concave portions, the wavelength in the air emitted by the photoluminescent layer limits the directivity angle of light having a λ _a , The intensity of the first light is maximized in the first direction predetermined by at least one of the plurality of convex portions and the plurality of concave portions, and the intensity of the second light is changed to the second direction different from the direction of the first light. Surface structure that maximizes in the direction,
An optical system for combining the first light and the second light,
With
Light emitting device.

[Item 63]
A photoluminescent layer that emits light including first light having _a wavelength of λ _a in air and second light having a wavelength of λ _{b in} air;
A surface structure that is formed on the surface of the photoluminescent layer and includes at least one of a plurality of convex portions and a plurality of concave portions, the wavelength in the air emitted by the photoluminescent layer limits the directivity angle of light of λ _a , The intensity of the first light is maximized in the first direction predetermined by at least one of the plurality of convex portions and the plurality of concave portions, and the intensity of the second light is changed to the second direction different from the direction of the first light. Surface structure that maximizes in the direction,
An optical system for combining the first light and the second light,
With
Light emitting device.

[Item 64]
A first light source,
A second light source,
Equipped with
The first light source is
A first photoluminescent layer which emits a first light including _a light having _a wavelength of λ _a in the air;
A first light-transmissive layer disposed in proximity to the photoluminescent layer,
A first surface structure, which is formed on at least one surface of a photoluminescent layer and a translucent layer and includes at least one of a plurality of first convex portions and a plurality of first concave portions, in the air emitted by the first photoluminescent layer. A first surface structure that limits the directivity angle of light having _a wavelength of λ _a ,
Equipped with
The second light source emits second light including light having a wavelength of λ _{b in} the air,
The first light emitted from the first light source and the second light emitted from the second light source are combined,
Light emitting device.

[Item 65]
The distance between the centers of two adjacent first convex portions in the first surface structure or the distance between the centers of two adjacent first concave portions is D _int-a, and the first photoluminescence for light with _a wavelength of λ _a in the air _65. The light emitting device according to item 64, wherein the relationship of λ _a /n _wav-a <D _int-a <λ _a is established, where n _wav-a is the refractive index of the layer.

[Item 66]
The first surface structure has at least one first periodic structure,
If the refractive index of the first photoluminescent layer for light having _a wavelength of λ _a in the air is n _wav-a and the period of at least one first periodic structure is p _a , then λ _a /n _wav-a <p _a Item 66. The light-emitting device according to Item 64 or 65, wherein the relationship of &lgr; _a holds.

[Item 67]
The intensity of light having _a wavelength λ _{a in} the air emitted from the first light source is maximum in a first direction predetermined by at least one of the plurality of first convex portions and the plurality of first concave portions. The light emitting device according to any one of 64 to 66.

[Item 68]
The second light source is
A second photoluminescent layer which emits a second light including a light having a wavelength of λ _b in the air;
A second light transmissive layer disposed in proximity to the second photoluminescent layer;
A second photoluminescent layer having a second surface structure including at least one of a plurality of second convex portions and a plurality of second concave portions formed on at least one surface of the second photoluminescent layer and the second light transmissive layer. A second surface structure that limits the directivity angle of light having a wavelength λ _b in the air emitted by
Have
The light-emitting device according to any of items 64 to 67.

[Item 69]
The distance between the centers of two adjacent second convex portions in the second surface structure or the distance between the centers of two adjacent second concave portions is D _int-b, and second photoluminescence with respect to light having a wavelength of λ _b in the air. _69. The light-emitting device according to item 68, wherein the relationship of λ _b /n _wav-b <D _int-b <λ _b is established, where n _wav-b is the refractive index of the layer.

[Item 70]
The second surface structure has at least one second periodic structure,
If the refractive index of the second photoluminescent layer for light having a wavelength of λ _b in the air is n _wav-b and the period of at least one second periodic structure is p _b , then λ _b /n _wav-b <p _b 70. The light-emitting device according to item 68 or 69, wherein the relationship of <λ _b is established.

[Item 71]
The intensity of light having a wavelength λ _{b in} the air emitted from the second light source is maximum in a second direction predetermined by at least one of the plurality of second convex portions and the plurality of second concave portions. The light-emitting device according to any one of 68 to 70.

[Item 72]
72. The light emitting device according to any of items 64 to 71, wherein the first light emitted from the first light source and the second light emitted from the second light source are combined to generate white light.

[Item 73]
Further comprising a third light source,
The third light source is
A third photoluminescent layer which emits a third light containing light having a wavelength of λ _c in the air;
A third light-transmitting layer disposed in proximity to the third photoluminescent layer,
A third photoluminescent layer having a third surface structure including at least one of a plurality of third convex portions and a plurality of third concave portions formed on at least one surface of the third photoluminescent layer and the third light transmissive layer. A third surface structure for limiting the directivity angle of light having a wavelength λ _c in the air emitted by
Have
The first light emitted from the first light source, the second light emitted from the second light source, and the third light emitted from the third light source are combined.
73. The light emitting device according to any of items 64 to 72.

[Item 74]
Let D _int-c be the distance between the centers of two adjacent third protrusions or the centers of two adjacent third recesses in the third surface structure, and the third photoluminescence for light with a wavelength in the air of λ _c. Item 73. The light-emitting device according to Item 73, wherein the relationship of λ _c /n _wav-c <D _int-c <λ _c is established, where n _wav-c is the refractive index of the layer.

[Item 75]
The third surface structure has at least one third periodic structure,
When the refractive index of the third photoluminescent layer wavelength in air to light of lambda _c and n _wav-c, a period of at least one third periodic structure and _{p c, λ c / n wav} -c <p c Item 73. The light-emitting device according to Item 73 or 74, wherein the relationship of λ _c is established.

[Item 76]
The intensity of light having a wavelength λ _{c in} the air emitted from the third light source is maximum in a third direction predetermined by at least one of the plurality of third convex portions and the plurality of third concave portions. 73. The light emitting device according to any one of 73 to 75.

[Item 77]
Item: White light is generated by combining the first light emitted from the first light source, the second light emitted from the second light source, and the third light emitted from the third light source. 73. The light emitting device according to any one of 73 to 76.

[Item 78]
Item 78. The light emitting device according to any one of Items 64 to 77, further including an optical fiber that receives the first light emitted from the first light source from one end and emits the first light from the other end.

[Item 79]
The second light source is arranged such that the second light passes through the first light source,
79. The light emitting device according to any one of items 64 to 78, wherein the first light emitted from the first light source and the second light that has passed through the first light source are combined.

[Item 80]
79. The light emitting device according to any of items 64 to 78, wherein the first light and the second light are combined inside the first light source.

[Item 81]
79. The light emitting device according to any one of items 64 to 78, further including an optical system that combines the first light and the second light outside the first light source.

[Item 82]
Item 82. The light emitting device according to item 81, wherein the optical system combines the first light and the second light and makes them enter the optical fiber.

[Item 83]
The second light emitted from the second light source includes excitation light that excites the luminescent material in the first photoluminescent layer to emit light,
The second light source causes the second light to be incident on the first photoluminescent layer,
Item 83. The light emission according to item 82, wherein the optical system combines the first light emitted from the first light emitting element and the second light emitted from the second light source and transmitted through the first light source, and makes the light enter the optical fiber. apparatus.

[Item 84]
A first optical fiber that takes in the first light emitted from the first light source from one end,
A second optical fiber for taking in the second light emitted from the second light source from one end,
Further equipped with,
The first optical fiber and the second optical fiber are connected to combine the first light and the second light at a connection point,
Item 77. The light-emitting device according to any one of Items 64 to 77.

[Item 85]
85. The light emitting device according to any of items 64 to 84, wherein the first photoluminescent layer and the first light transmitting layer are in contact with each other.

[Item 86]
A first light source,
A second light source,
Equipped with
The first light source is
A transparent layer,
A surface structure formed on the surface of the light-transmitting layer and including at least one of a plurality of convex portions and a plurality of concave portions,
A photoluminescence layer which is disposed in proximity to the surface structure and emits a first light including _a light having _a wavelength of λ _{a in} air,
The surface structure limits the directivity angle of light having _a wavelength λ _{a in} the air emitted by the photoluminescence layer,
The second light source emits second light including light having a wavelength of λ _{b in} the air,
The first light emitted from the first light source and the second light emitted from the second light source are combined,
Light emitting device.

[Item 87]
A first light source,
A second light source,
Equipped with
The first light source is
A photoluminescence layer that emits a first light including _a light having _a wavelength of λ _a in the air;
A translucent layer having a refractive index higher than that of the photoluminescent layer,
Formed on the surface of the light-transmitting layer, and having a surface structure including at least one of a plurality of convex portions and a plurality of concave portions,
The surface structure limits the directivity angle of light having _a wavelength λ _{a in} the air emitted by the photoluminescence layer,
The second light source emits second light including light having a wavelength of λ _{b in} the air,
The first light emitted from the first light source and the second light emitted from the second light source are combined,
Light emitting device.

[Item 88]
A first light source,
A second light source,
Equipped with
The first light source is
A photoluminescence layer that emits first light including light having _a wavelength of λ _a in the air; and a surface structure that is formed on the surface of the photoluminescence layer and that includes at least one of a plurality of convex portions and a plurality of concave portions. Then
The surface structure limits the directivity angle of light having _a wavelength λ _{a in} the air emitted by the photoluminescence layer,
The second light source emits second light including light having a wavelength of λ _{b in} the air,
The first light emitted from the first light source and the second light emitted from the second light source are combined,
Light emitting device.

[Item 89]
A light source section,
An image forming unit having a light modulation element,
An optical fiber that takes in light from the light source part from one end and guides it to the image forming part,
Equipped with
The light source is
Excitation light source,
A photoluminescence layer which receives excitation light from an excitation light source and emits light having _a wavelength in air of λ _a ;
A translucent layer disposed in proximity to the photoluminescent layer,
Formed on the surface of at least one of the photoluminescent layer and the translucent layer, and having a surface structure including at least one of a plurality of convex portions and a plurality of concave portions,
The surface structure is a projection device that limits the directivity angle of light having _a wavelength λ _{a in} the air emitted by the photoluminescent layer.

[Item 90]
A light source section having an excitation light source,
An image forming unit,
An optical fiber that receives the excitation light from the excitation light source from one end and guides it to the image forming unit,
Equipped with
The image forming unit
A photoluminescence layer which receives excitation light and emits light having _a wavelength in air of λ _a ;
A translucent layer disposed in proximity to the photoluminescent layer,
A surface structure formed on the surface of at least one of the photoluminescent layer and the transparent layer, and including at least one of a plurality of convex portions and a plurality of concave portions,
And _a light modulation element that receives light having _a wavelength of λ _{a in} the air emitted by the photoluminescence layer,
The surface structure is a projection device that limits the directivity angle of light having _a wavelength λ _{a in} the air emitted by the photoluminescent layer.

[Item 91]
A light source section,
An image forming unit having a light modulation element,
An optical fiber that takes in light from the light source part from one end and guides it to the image forming part,
Equipped with
The light source is
Excitation light source,
A transparent layer,
A surface structure formed on the surface of the light-transmitting layer and including at least one of a plurality of convex portions and a plurality of concave portions,
A photoluminescence layer which is arranged in proximity to the surface structure and which receives excitation light from an excitation light source and emits light having _a wavelength in air of λ _a ;
The surface structure is a projection device that limits the directivity angle of light having _a wavelength λ _{a in} the air emitted by the photoluminescent layer.

[Item 92]
A light source section having an excitation light source,
An image forming unit,
An optical fiber that receives the excitation light from the excitation light source from one end and guides it to the image forming unit,
Equipped with
The image forming unit
A transparent layer,
A surface structure formed on the surface of the light-transmitting layer and including at least one of a plurality of convex portions and a plurality of concave portions,
A photoluminescence layer which is arranged close to the surface structure and which receives excitation light and emits light having _a wavelength in air of λ _a ;
And _a light modulation element that receives light having _a wavelength of λ _{a in} the air emitted by the photoluminescence layer,
The surface structure is a projection device that limits the directivity angle of light having _a wavelength λ _{a in} the air emitted by the photoluminescent layer.

[Item 93]
A light source section,
An image forming unit having a light modulation element,
An optical fiber that takes in light from the light source part from one end and guides it to the image forming part,
Equipped with
The light source is
Excitation light source,
A photoluminescence layer which receives excitation light from an excitation light source and emits light having _a wavelength in air of λ _a ;
A translucent layer having a refractive index higher than that of the photoluminescent layer,
Formed on the surface of the light-transmitting layer, and having a surface structure including at least one of a plurality of convex portions and a plurality of concave portions,
The surface structure is a projection device that limits the directivity angle of light having _a wavelength λ _{a in} the air emitted by the photoluminescent layer.

[Item 94]
A light source section having an excitation light source,
An image forming unit,
An optical fiber that receives the excitation light from the excitation light source from one end and guides it to the image forming unit,
Equipped with
The image forming unit
A photoluminescence layer which receives excitation light and emits light having _a wavelength in air of λ _a ;
A translucent layer having a refractive index higher than that of the photoluminescent layer,
A surface structure formed on the surface of the light-transmitting layer and including at least one of a plurality of convex portions and a plurality of concave portions,
And _a light modulation element that receives light having _a wavelength of λ _{a in} the air emitted by the photoluminescence layer,
The surface structure is a projection device that limits the directivity angle of light having _a wavelength λ _{a in} the air emitted by the photoluminescent layer.

[Item 95]
95. The projection device according to any of items 89 to 94, wherein the photoluminescent layer and the translucent layer are in contact with each other.

[Item 96]
A light source section,
An image forming unit having a light modulation element,
An optical fiber that takes in light from the light source part from one end and guides it to the image forming part,
Equipped with
The light source is
Excitation light source,
A photoluminescence layer which receives excitation light from an excitation light source and emits light having _a wavelength in air of λ _a ;
Formed on the surface of the photoluminescent layer, having a surface structure including at least one of a plurality of convex portions and a plurality of concave portions,
The surface structure is a projection device that limits the directivity angle of light having _a wavelength λ _{a in} the air emitted by the photoluminescent layer.

[Item 97]
A light source section having an excitation light source,
An image forming unit,
An optical fiber that receives the excitation light from the excitation light source from one end and guides it to the image forming unit,
Equipped with
The image forming unit
A photoluminescence layer which receives excitation light and emits light having _a wavelength in air of λ _a ;
A surface structure formed on the surface of the photoluminescent layer and including at least one of a plurality of convex portions and a plurality of concave portions,
And _a light modulation element that receives light having _a wavelength of λ _{a in} the air emitted by the photoluminescence layer,
The surface structure is a projection device that limits the directivity angle of light having _a wavelength λ _{a in} the air emitted by the photoluminescent layer.

[Item 98]
The surface structure has a quasi-guided mode that maximizes the intensity of light having _a wavelength of λ _{a in} the air emitted from the photoluminescence layer in the first direction that is predetermined by the surface structure, inside the photoluminescence layer. Item 98. The projection device according to any one of items 89 to 97, which is formed in the above.

[Item 99]
98. The projection device according to any of items 89 to 97, wherein the light having _a wavelength λ _a in the air has a maximum intensity in a first direction predetermined by the surface structure.

[Item 100]
101. The projection device according to any one of items 89 to 99, wherein a directivity angle with respect to a first direction of light having _a wavelength in air of λ _a is less than 15°.

[Item 101]
101. The projection device according to any one of items 89 to 100, wherein the surface structure limits the directivity angle of light having _a wavelength λ _{a in} the air emitted by the photoluminescent layer to less than 15°.

[Item 102]
Let D _int be the distance between two adjacent convex portions or two adjacent concave portions in the surface structure, and let n _wav-a be the refractive index of the photoluminescent layer for light with _a wavelength λ _a in the air, λ _a 101. The projection device according to any one of items 89 to 101, wherein _a relationship of /n _wav-a <D _int <λ _a is established.

[Item 103]
The surface structure has at least one periodic structure,
When the period of at least one periodic structure and _{p a, λ a / n wav} -a < relationship p _a <λ _a is satisfied, projection apparatus as described in any one of 89 102.

A light emitting device according to an embodiment of the present disclosure includes an excitation light source, a light emitting element arranged on an optical path of excitation light from the excitation light source, and a condenser lens arranged on an optical path of light emitted from the light emitting element. Have. The light emitting element includes a photoluminescence layer that receives excitation light and emits light having _a wavelength λ _{a in} air. As described later in detail, the light emitting element in the light emitting device of the present disclosure has a novel structure capable of controlling the light emission efficiency, directivity, or polarization characteristics of the photoluminescent material. According to an embodiment of the present disclosure, it is possible to provide a light emitting device having a novel structure using a photoluminescent material. Hereinafter, first, an example of a light emitting element that can be applied to the light emitting device of the present disclosure will be described. Details of the overall configuration of the light emitting device will be described later.

A light-emitting device according to an embodiment of the present disclosure is a photoluminescent layer, a light-transmissive layer disposed in proximity to the photoluminescent layer, a photoluminescent layer and at least one surface of the light-transmissive layer, and a plurality of convex portions. And a surface structure including at least one of the plurality of recesses. This surface structure limits the directional angle of light emitted by the photoluminescent layer and having a wavelength of λ _{a in} air. The surface structure can be a submicron structure extending in-plane of the photoluminescent or light transmissive layer. The submicron structure may be, for example, a periodic structure including at least one of a convex portion and a concave portion. Submicron structures include, for example, multiple protrusions or multiple recesses. The light emitted from the photoluminescent layer includes the first light having _a wavelength λ _a in the air, the distance between adjacent convex portions or concave portions is D _int , and the refractive index of the photoluminescent layer with respect to the first light is n. _{Assuming wav-a} , the relationship of λ _a /n _wav-a <D _int <λ _a holds. Alternatively, if the period in the periodic structure is p _a , the relationship of λ _a /n _wav-a <p _a <λ _a holds. The wavelength λ _a is, for example, within the wavelength range of visible light (for example, 380 nm or more and 780 nm or less). For applications that utilize infrared light, the wavelength λ _a can exceed 780 nm. On the other hand, in applications using ultraviolet light, the wavelength λ _a may be less than 380 nm. In the present disclosure, electromagnetic waves including infrared rays and ultraviolet rays are generally referred to as “light” for convenience.

The photoluminescent layer comprises a photoluminescent material. The photoluminescent material means a material that emits light upon receiving excitation light. Photoluminescent materials include fluorescent materials and phosphorescent materials in a narrow sense, include not only inorganic materials but also organic materials (for example, dyes), and further include quantum dots (that is, semiconductor fine particles). The photoluminescent layer may include a matrix material (ie, host material) in addition to the photoluminescent material. The matrix material is, for example, an inorganic material such as glass or oxide, or a resin.

The translucent layer arranged in the vicinity of the photoluminescent layer is formed of a material having a high transmittance for the light emitted by the photoluminescent layer, for example, an inorganic material or a resin. The translucent layer can be formed of, for example, a dielectric (in particular, an insulator that absorbs less light). The translucent layer may be, for example, a substrate that supports the photoluminescent layer. When the surface of the photoluminescence layer on the air side has a submicron structure, the air layer can be a light transmitting layer.

A surface structure including at least one of a plurality of convex portions and a plurality of concave portions is formed on the surface of at least one of the photoluminescent layer and the light transmitting layer. Here, the “surface” means a portion in contact with another substance (that is, an interface). When the light transmissive layer is a gas layer such as air, the interface between the gas layer and another substance (for example, the photoluminescence layer) is the surface of the light transmissive layer. This surface structure can also be referred to as an "uneven structure". The surface structure typically includes a portion in which a plurality of convex portions or a plurality of concave portions are periodically arranged in one dimension or two dimensions. Such surface structures can be referred to as "periodic structures". The plurality of protrusions and the plurality of recesses are formed at the boundary between two members (or media) having different refractive indexes that are in contact with each other. Therefore, it can be said that the “periodic structure” includes a portion in which the refractive index periodically changes in a certain direction. Here, the term “periodic” is not limited to a mode that is strictly periodic, but includes a mode that can be said to be approximately periodic. In the present specification, the distance between two adjacent centers (hereinafter, sometimes referred to as “center interval”) of a plurality of continuous protrusions or recesses is any two adjacent protrusions or recesses. Also, when is within a range of ±15% of a certain value p, that part is considered to be a periodic structure having a period p.

In the present specification, the “convex portion” means a portion that is raised with respect to the reference height portion. The “recess” means a portion that is recessed with respect to the reference height portion. Depending on the shapes, sizes, and distributions of the convex portions and the concave portions, it may be difficult to easily determine which is the convex portion and which is the concave portion. For example, in the cross-sectional view shown in FIG. 107, it can be interpreted that the member 610 has a concave portion and the member 620 has a convex portion, and vice versa. Whatever the interpretation may be, it can be said that each of the member 610 and the member 620 has at least one of a plurality of protrusions and/or recesses.

The distance between the centers of two adjacent convex portions or two adjacent concave portions in the surface structure (period p in the periodic structure) is typically shorter than the wavelength λ _a of the light emitted by the photoluminescent layer in air. .. When the light emitted from the photoluminescent layer is visible light, short-wave near-infrared rays, or ultraviolet rays, the distance is shorter than the order of micrometers (that is, the order of microns). Therefore, such a surface structure may be referred to as a “submicron structure”. A "sub-micron structure" may include in part a portion having a center spacing or period greater than 1 micrometer (μm). In the following description, a photoluminescence layer that emits visible light is mainly assumed, and the term “submicron structure” may be used as a term that means a surface structure. However, the following discussion holds in the same manner even for a surface structure having a fine structure exceeding the sub-micron order (for example, a fine structure of the micron order used in the application utilizing infrared rays).

In the embodiments of the present disclosure, a unique electric field distribution is formed inside the photoluminescent layer and the light transmissive layer, as will be described later in detail with reference to calculation results and experimental results. It is formed by the guided light interacting with submicron structures (ie surface structures). The mode of light forming such an electric field distribution can be expressed as a “pseudo-guided mode”. By utilizing this pseudo-guided mode, it is possible to obtain the effects of increasing the luminous efficiency of photoluminescence, improving the directivity, and selecting the polarization, as described below. In the following description, the term "pseudo-guided mode" may be used to describe a novel configuration and/or novel mechanism found by the present inventors. The description is merely an example and is not intended to limit the disclosure in any way.

The submicron structure includes, for example, a plurality of convex portions, and when the center-to-center distance between adjacent convex portions is D _int , the relationship of λ _a /n _wav-a <D _int <λ _a can be satisfied. The submicron structure may include a plurality of recesses instead of the plurality of projections. Hereinafter, for simplicity, the submicron structure will be described as having a plurality of convex portions. λ represents the wavelength of light, and λ _a with the subscript “a” represents the wavelength of light in air. n _wav is the refractive index of the photoluminescent layer. When the photoluminescence layer is a medium in which a plurality of materials are mixed, the average refractive index obtained by weighting the refractive index of each material with each volume ratio is n _wav . Since the refractive index n generally depends on the wavelength, it is desirable to clearly indicate that it is the refractive index for light of λ _a as n _wav-a , but it may be omitted for simplicity. n _wav is basically the refractive index of the photoluminescent layer. However, when the refractive index of the layer adjacent to the photoluminescent layer is larger than the refractive index of the photoluminescent layer, the refractive index of the layer having the large refractive index and the photoluminescent layer. The average refractive index obtained by weighting the refractive index of the layer with each volume ratio is n _wav . This is because, in this case, it is optically equivalent to the case where the photoluminescence layer is composed of a plurality of layers of different materials.

_Letting n _eff be the effective refractive index of the medium for light in the pseudo-guided mode, then n _a <n _eff <n _wav is satisfied. Here, n _a is the refractive index of air. Considering that light in the pseudo-waveguide mode propagates inside the photoluminescent layer while being totally reflected at an incident angle θ, the effective refractive index n _eff can be written as n _eff =n _wav sin θ. Further, since the effective refractive index n _eff is determined by the refractive index of the medium existing in the region where the electric field of the pseudo-guided mode is distributed, for example, when the submicron structure is formed in the light transmitting layer, the photoluminescence layer It depends not only on the refractive index but also on the refractive index of the transparent layer. Also, since the electric field distribution differs depending on the polarization direction of the pseudo-guided mode (TE mode and TM mode), the effective refractive index n _eff may differ between the TE mode and the TM mode.

The submicron structure is formed in at least one of the photoluminescent layer and the light transmitting layer. A submicron structure may be formed at the interface between the photoluminescent layer and the transparent layer when the photoluminescent layer and the transparent layer are in contact with each other. At this time, the photoluminescent layer and the translucent layer have a submicron structure. The photoluminescent layer may not have a submicron structure. At this time, the light-transmitting layer having a submicron structure is arranged close to the photoluminescence layer. Here, that the light transmissive layer (or its submicron structure) is close to the photoluminescent layer typically means that the distance between them is not more than half the wavelength λ _a . Thereby, the electric field of the guided mode reaches the submicron structure, and the pseudo guided mode is formed. However, when the refractive index of the light-transmitting layer is larger than that of the photoluminescent layer, the light reaches the light-transmitting layer even if the above relationship is not satisfied, so that the submicron structure of the light-transmitting layer and the photoluminescent layer are The distance between may be more than half the wavelength λ _a . In this specification, when the photoluminescent layer and the light-transmitting layer are in a positional relationship such that the electric field of the guided mode reaches the submicron structure and the pseudo guided mode is formed, they are associated with each other. Sometimes expressed as being.

When the submicron structure satisfies the relationship of λ _a /n _wav-a <D _int <λ _a as described above, the surface structure is characterized by the size of submicron order in the application utilizing visible light. To be The sub-micron structure may include at least one periodic structure, such as in a light emitting element of a light emitting device of the embodiments described in detail below. At least one of the periodic structure, when the period as p _a, may satisfy the relation of _{λ a / n wav-a <} p a <λ a. That is, the submicron structure may include a periodic structure in which the distance D _int between adjacent convex portions is constant at p _a . When the submicron structure includes such a periodic structure, the light of the pseudo-guided mode is diffracted by the submicron structure by repeating the interaction with the periodic structure while propagating. This is a phenomenon in which light acts on the periodic structure while being guided (that is, repeating total reflection), unlike the phenomenon that light propagating in free space is diffracted by the periodic structure. Therefore, even if the phase shift due to the periodic structure is small (that is, even if the height of the periodic structure is small), light can be efficiently diffracted.

If the mechanism described above is used, the luminous efficiency of photoluminescence is increased by the effect of the electric field being enhanced by the pseudo-guided mode, and the generated light is coupled to the pseudo-guided mode. The traveling angle of the light in the pseudo-guided mode is bent by the diffraction angle defined by the periodic structure. By utilizing this, it is possible to emit light of a specific wavelength in a specific direction. That is, the directivity is remarkably improved as compared with the case where the periodic structure does not exist. Further, since the TE mode and the TM mode have different effective refractive indices n _eff (=n _wav sin θ), it is possible to obtain high polarization selectivity at the same time. For example, as will be shown later as an experimental example, it is possible to obtain a light emitting element that strongly emits linearly polarized light (for example, TM mode) of a specific wavelength (for example, 610 nm) in the front direction. At this time, the directivity angle of the light emitted in the front direction is less than 15°, for example. Here, the "directivity angle" is defined as the angle between the direction in which the intensity is maximum and the direction in which the intensity is 50% of the maximum intensity for the linearly polarized light having a specific wavelength to be emitted. That is, the directivity angle is an angle on one side when the direction in which the intensity is maximum is 0°. As described above, the periodic structure (that is, the surface structure) in the embodiment of the present disclosure limits the directivity angle of light having _a specific wavelength λ _a . In other words, the light distribution of the light of the wavelength λ _a is made narrower than that in the case where there is no periodic structure. Such a light distribution in which the directivity angle is reduced as compared with the case where no periodic structure exists may be referred to as “narrow-angle light distribution”. The periodic structure of the embodiment of the present disclosure, limits the directivity angle of light of wavelength lambda _a, but the embodiment is not emit any light of the wavelength lambda _a narrow angle. For example, in the example shown in FIG. 29, which will be described later, light of the wavelength λ _a is slightly emitted also in the direction of an angle (for example, 20° to 70°) away from the direction of maximum intensity. However, as a whole, the emitted light of the wavelength λ _a is concentrated in the range of 0° to 20°, and the directivity angle is limited.

Note that the periodic structure in the exemplary embodiment of the present disclosure has a period shorter than the wavelength λ _{a of} light, unlike a general diffraction grating. A general diffraction grating has a period sufficiently longer than the wavelength λ _{a of} light, and as a result, a light of a specific wavelength is diffracted into a plurality of diffracted lights such as 0th order light (that is, transmitted light) and ±1st order diffracted light. It is divided into two and emitted. In such a diffraction grating, high-order diffracted light is generated on both sides of the 0th-order light. High-order diffracted light generated on both sides of the 0th-order light in the diffraction grating makes it difficult to realize narrow-angle light distribution. In other words, the conventional diffraction grating does not exert the effect peculiar to the embodiment of the present disclosure that the directivity angle of light is limited to a predetermined angle (for example, about 15°). In this respect, the periodic structure in the embodiment of the present disclosure has a property that is significantly different from the conventional diffraction grating.

When the periodicity of the submicron structure becomes low, the directivity, the luminous efficiency, the degree of polarization and the wavelength selectivity become weak. If necessary, the periodicity of the submicron structure may be adjusted. The periodic structure may be a one-dimensional periodic structure having high polarization selectivity or a two-dimensional periodic structure capable of reducing the polarization degree.

Submicron structures may include multiple periodic structures. For example, the plurality of periodic structures have mutually different periods (pitch). Alternatively, the plurality of periodic structures have mutually different directions (axes) having periodicity, for example. The plurality of periodic structures may be formed in the same plane or may be laminated. Of course, the light emitting element may have a plurality of photoluminescent layers and a plurality of light transmitting layers. They may have multiple submicron structures.

The submicron structure can be used not only for controlling the light emitted by the photoluminescent layer but also for efficiently guiding the excitation light to the photoluminescent layer. That is, the excitation light is diffracted by the submicron structure and is coupled to the pseudo-waveguide mode that guides the photoluminescence layer and the light transmitting layer, whereby the photoluminescence layer can be efficiently excited. Letting λ _ex be the wavelength of light exciting the photoluminescent material in air and n _{wav-ex being} the refractive index of the photoluminescent layer for this exciting light, the relationship of λ _ex /n _wav-ex <D _int <λ _ex It suffices to use a submicron structure in which n _wav-ex is the refractive index at the excitation wavelength of the photoluminescent material. When the period is p _ex , a submicron structure having a periodic structure in which the relationship of λ _ex /n _wav-ex <p _ex <λ _ex is established may be used. The wavelength λ _{ex of the} excitation light is, for example, 450 nm, but may be shorter than visible light. When the wavelength of the excitation light is in the visible light range, the excitation light may be emitted together with the light emitted by the photoluminescence layer.

[2. Knowledge as the basis of the present disclosure]
Before describing specific embodiments of the present disclosure, first, the knowledge on which the present disclosure is based will be described, and subsequently, an exemplary configuration of a light emitting device having a photoluminescence layer will be described. As described above, photoluminescent materials used in fluorescent lamps, white LEDs and the like emit isotropic light. Optical components such as a reflector and a lens are generally required to illuminate a specific direction with light using a photoluminescent material. However, if the photoluminescent layer itself emits light with directivity, for example, the lens can be made smaller, which can greatly reduce the size of the optical device or instrument. Based on such an idea, the present inventors have studied in detail the structure of the photoluminescent layer in order to obtain directional light emission.

The inventors of the present invention first considered that the light emission itself should have a specific directionality so that the light from the photoluminescent layer is biased in a specific direction. The light emission rate Γ, which is an index characterizing light emission, is represented by the following formula (1) according to Fermi's Golden Rule.

In Expression (1), r is a vector representing a position, λ is a wavelength of light, d is a dipole vector, E is an electric field vector, and ρ is a density of states. In many substances except some crystalline substances, the dipole vector d has a random orientation. Further, when the size and thickness of the photoluminescence layer are sufficiently larger than the wavelength of light, the magnitude of the electric field E is almost constant regardless of the direction. Therefore, in most cases, the value of <(d·E(r))> ² does not depend on the direction. That is, the emission rate Γ is constant regardless of the direction. Therefore, in most cases, the photoluminescent layer emits light isotropically.

On the other hand, from the formula (1), in order to obtain anisotropic light emission, it is necessary to arrange the dipole vector d in a specific direction or to enhance the component of the electric field vector in a specific direction. I know there is. Directional light emission can be realized by making any of these measures. In the embodiment of the present disclosure, a pseudo-guided mode in which an electric field component in a specific direction is enhanced by the effect of confining light in the photoluminescent layer is used. The configuration for that purpose is examined, and the detailed analysis results are described below.

[3. Configuration that strengthens only the electric field in a specific direction]
The present inventors considered controlling light emission using a guided mode with a strong electric field. When the waveguide structure itself includes a photoluminescent material, the generated light can be coupled to the waveguide mode. However, if the waveguiding structure is simply formed by using the photoluminescent material, the emitted light becomes a waveguiding mode, so that almost no light is emitted in the front direction. Therefore, the present inventors considered combining a waveguide containing a photoluminescent material and a periodic structure. When the periodic structure is close to the waveguide and the electric field of light is guided while overlapping with the periodic structure, a pseudo-guided mode is formed by the action of the periodic structure. That is, this pseudo-guided mode is a guided mode limited by the periodic structure, and is characterized in that the antinode of the electric field amplitude occurs at the same period as the period of the periodic structure. This mode is a mode in which the electric field in a specific direction is strengthened by confining light in the waveguide structure. Further, this mode interacts with the periodic structure and is converted into propagating light in a specific direction by the diffraction effect. Therefore, light can be emitted to the outside of the waveguide. Furthermore, the electric field is not enhanced because light other than the pseudo-guided mode has a small effect of being confined in the waveguide. Therefore, most of the emitted light is coupled into the pseudo-guided mode having a large electric field component.

That is, the present inventors configured the waveguide provided with the periodic structure close to each other by the photoluminescence layer containing the photoluminescence material (or the waveguide layer having the photoluminescence layer) to generate light. , It was considered to realize a directional light source by coupling with a pseudo-guided mode that is converted into propagating light in a specific direction.

As a simple structure of the waveguide structure, we focused on a slab type waveguide. The slab type waveguide is a waveguide in which the light guiding portion has a flat plate structure. FIG. 30 is a perspective view schematically showing an example of a slab type waveguide. When the refractive index of the waveguide 110S shown in FIG. 30 is higher than the refractive index of the substrate 140 that supports the waveguide 110S, there is a mode of light propagating in the waveguide 110S. By configuring such a slab-type waveguide to include a photoluminescence layer, the electric field of the light generated from the light emitting point largely overlaps with the electric field of the guided mode, so that most of the light generated in the photoluminescence layer is guided. Can be coupled to wave modes. Furthermore, by setting the thickness of the photoluminescence layer to be about the wavelength of light, it is possible to create a situation in which only a guided mode with a large electric field amplitude exists.

Further, when the periodic structure is close to the photoluminescent layer, the electric field of the guided mode interacts with the periodic structure to form a pseudo guided mode. Even if the photoluminescent layer is composed of a plurality of layers, a pseudo-guided mode can be formed if the electric field of the guided mode reaches the periodic structure. It is not necessary that all of the photoluminescent layer is a photoluminescent material, and it is sufficient that at least a part of the region has a function of emitting light.

When the periodic structure is made of metal, a mode is formed by the guided mode and the effect of plasmon resonance. This mode has different properties from the above-mentioned pseudo-guided mode. Further, in this mode, since the absorption by the metal is large, the loss becomes large and the effect of enhancing the light emission becomes small. Therefore, it is beneficial to use a dielectric material having a small absorption as the periodic structure.

The present inventors first formed a periodic structure on the surface of such a waveguide to couple the generated light to a pseudo-waveguide mode that can be emitted as propagating light in a specific angular direction. investigated. FIG. 1A is a perspective view schematically showing an example of a light emitting device 100 having such a waveguide (for example, a photoluminescence layer) 110 and a periodic structure (for example, a part of a translucent layer) 120. Hereinafter, when the transparent layer has a periodic structure (that is, when a periodic submicron structure is formed in the transparent layer), the surface structure 120 may be referred to as a transparent layer 120. In this example, the surface structure 120 is a one-dimensional periodic structure in which a plurality of stripe-shaped convex portions each extending in the y direction are arranged at equal intervals in the x direction. FIG. 1B is a sectional view of the light emitting device 100 taken along a plane parallel to the xz plane. When a periodic structure with a period p is provided so as to be in contact with the waveguide 110, a pseudo-guided mode having a wave number k _wav in the in-plane direction is converted into propagating light outside the waveguide, and the wave number k _out is expressed by the following equation. It can be represented by (2).

M in Formula (2) is an integer and represents the order of diffraction.

Here, for the sake of simplicity, it is assumed that the light guided in the waveguide is approximately a light beam propagating at the angle θ _wav , and the following expressions (3) and (4) are established.

In these equations, λ ₀ is the wavelength of light in air, n _wav is the refractive index of the waveguide, n _out is the refractive index of the medium on the exit side, and θ _out is the light emitted to the substrate or air outside the waveguide. Is the output angle. From the expressions (2) to (4), the emission angle θ _out can be expressed by the following expression (5).

From equation (5), it can be seen that when n _wav sin θ _wav =mλ ₀ /p holds, θ _out =0 and light can be emitted in a direction perpendicular to the plane of the waveguide (that is, in front).

Based on the above principle, the generated light is coupled into a specific pseudo-guided mode, and is converted into light with a specific emission angle by using the periodic structure, so that strong light is emitted in that direction. It is considered possible.

There are some constraints for realizing the above situation. First, in order for the pseudo-waveguide mode to exist, it is necessary that the light propagating in the waveguide be totally reflected. The condition for this is expressed by the following equation (6).

In order to diffract the pseudo-guided mode by the periodic structure and emit the light to the outside of the waveguide, it is necessary that -1<sin θ _out <1 in the equation (5). Therefore, it is necessary to satisfy the following expression (7).

On the other hand, considering the formula (6), it is understood that the following formula (8) should be satisfied.

Furthermore, in order to make the direction of the light emitted from the waveguide 110 to be the front direction (θ _out =0), it is understood from the equation (5) that the following equation (9) is necessary.

From Expression (9) and Expression (6), it is understood that the necessary condition is Expression (10) below.

When the periodic structure as shown in FIGS. 1A and 1B is provided, the high-order diffraction efficiency in which m is 2 or more is low, so it is preferable to design mainly the 1st-order diffracted light with m=1. .. Therefore, in the periodic structure according to the exemplary embodiment of the present disclosure, the period p is determined so that m=1 and the following formula (11) obtained by modifying the formula (10) is satisfied.

As shown in FIGS. 1A and 1B, when the waveguide (for example, the photoluminescence layer) 110 is not in contact with the transparent substrate, n _out is the refractive index of air (about 1.0). The period p may be determined so as to satisfy (12).

On the other hand, as illustrated in FIGS. 1C and 1D, a structure in which a photoluminescent layer as the waveguide 110 and the surface structure 120 are formed on the substrate 140 may be adopted. A transparent substrate is typically used as the substrate 140. Hereinafter, the substrate 140 may be referred to as the transparent substrate 140.

When the waveguide 110 and the surface structure 120 are formed on the transparent substrate 140, the refractive index n _{s of the} substrate is larger than the refractive index of air. Therefore, in the equation (11), n _out =n _s The period p may be determined so as to satisfy (13).

In addition, in the formulas (12) and (13), the case where m=1 in the formula (10) is assumed, but m≧2 may be satisfied. That is, as shown in FIGS. 1A and 1B, when both surfaces of the light emitting element 100 are in contact with the air layer, m is an integer of 1 or more and the cycle p is set so as to satisfy the following expression (14). It should be done.

Similarly, when the photoluminescence layer as the waveguide 110 is formed on the transparent substrate 140 as in the light emitting device 100a shown in FIGS. 1C and 1D, the period is set so as to satisfy the following formula (15). It is only necessary to set p.

By determining the period p of the periodic structure so as to satisfy the above inequality, the light generated from the photoluminescence layer can be emitted in the front direction, and a light emitting device having directivity can be realized. In the following, the waveguide 110 may be referred to as the photoluminescence layer 110.

[4. Verification by calculation]
[4-1. Period, wavelength dependence]
The present inventors verified by optical analysis whether it is possible to actually emit light in the specific direction as described above. The optical analysis was performed by calculation using Cybernet's Diffract MOD. In these calculations, when the light is vertically incident on the light emitting element from the outside, the increase or decrease in the absorption of the light in the photoluminescent layer is calculated to obtain the enhancement degree of the light emitted vertically to the outside. The process in which light incident from the outside is coupled to the pseudo-guided mode and is absorbed by the photoluminescent layer is a process in which light emitted from the photoluminescent layer is coupled to the pseudo-guided mode and converted into propagating light that is emitted vertically to the outside. Corresponds to calculating the reverse process of the process. Further, also in the calculation of the electric field distribution of the pseudo-guided mode, the electric field when light is incident from the outside is similarly calculated.

The thickness of the photoluminescent layer is 1 μm, the refractive index of the photoluminescent layer is n _wav =1.8, the height of the periodic structure is 50 nm, and the refractive index of the periodic structure is 1.5. FIG. 2 shows the result of calculating the enhancement degree of the light emitted in the front direction while changing the respective values. As shown in FIG. 1A, the calculation model has a uniform one-dimensional periodic structure in the y direction, and the light polarization is calculated as a TM mode having an electric field component parallel to the y direction. From the results of FIG. 2, it can be seen that the peak of enhancement exists in a certain combination of a wavelength and a period. In addition, in FIG. 2, the magnitude of the enhancement is represented by the shade of the color. The darker (that is, black) has a larger enhancement, and the lighter (that is, white) has a smaller enhancement.

In the above calculation, the cross section of the periodic structure is assumed to be a rectangle as shown in FIG. 1B. FIG. 3 is a graph showing the conditions of m=1 and m=3 in the equation (10). Comparing FIG. 2 and FIG. 3, it can be seen that the peak positions in FIG. 2 exist at the positions corresponding to m=1 and m=3. The intensity is higher when m=1 because the diffraction efficiency of the 1st-order diffracted light is higher than that of the 3rd-order or higher-order diffracted light. The peak of m=2 does not exist because the diffraction efficiency in the periodic structure is low.

It can be confirmed in FIG. 2 that a plurality of lines exist in the regions corresponding to m=1 and m=3 shown in FIG. It is considered that this is because there are a plurality of pseudo guided modes.

[4-2. Thickness dependence]
In FIG. 4, the refractive index of the photoluminescent layer is n _wav =1.8, the period of the periodic structure is 400 nm, the height is 50 nm, the refractive index is 1.5, and the emission wavelength and the thickness t of the photoluminescent layer are changed. Then, the result of calculating the enhancement degree of the light output in the front direction is shown. It can be seen that the enhancement of light reaches a peak when the thickness t of the photoluminescent layer is a specific value.

FIG. 5A and FIG. 5B show the results of calculating the electric field distribution of the mode guided in the x direction when the wavelength is 600 nm and the thickness t is 238 nm and 539 nm in which the peak exists in FIG. For comparison, FIG. 5C shows the result of similar calculation performed at t=300 nm where no peak exists. Similar to the above, the calculation model was assumed to be a one-dimensional periodic structure that was uniform in the y direction. In each figure, the black region indicates that the electric field strength is high, and the white region indicates that the electric field strength is low. When t=238 nm and 539 nm, there is a distribution of high electric field strength, whereas when t=300 nm, the electric field strength is low overall. This is because when t=238 nm and 539 nm, a guided mode exists and light is strongly confined. Further, there is always a portion (belly) having the strongest electric field immediately below the convex portion or the convex portion, and an electric field having a correlation with the surface structure 120 (in this example, the periodic structure) is generated. That is, it is understood that the guided mode is obtained according to the arrangement of the surface structure 120. Further, comparing the case of t=238 nm and the case of t=539 nm, it is found that these are modes in which the number of nodes (white part) of the electric field in the z direction is different by one.

[4-3. Polarization dependence]
Next, in order to confirm the polarization dependence, light enhancement was calculated under the same conditions as in the calculation of FIG. 2 for the case where the polarization of light was the TE mode having an electric field component perpendicular to the y direction. The result of this calculation is shown in FIG. Compared to the case of the TM mode (FIG. 2), the peak position is slightly changed, but the peak position is within the area shown in FIG. Therefore, it was confirmed that the configuration of this embodiment is effective for both TM mode and TE mode polarized light.

[4-4.2 Two-dimensional periodic structure]
Furthermore, the effect of the two-dimensional periodic structure was examined. FIG. 7A is a plan view showing a part of a two-dimensional surface structure 120′ in which concave portions and convex portions are arranged in both the x direction and the y direction. In the figure, the black areas are convex portions and the white areas are concave portions. In such a two-dimensional periodic structure, it is necessary to consider diffraction in both the x and y directions. Diffraction only in the x direction or only in the y direction is the same as in the one-dimensional case, but there is also diffraction in a direction having both x and y components (for example, an oblique 45° direction), so that the one-dimensional case It is expected that different results will be obtained. FIG. 7B shows the result of calculating the light enhancement factor for such a two-dimensional periodic structure. The calculation conditions other than the periodic structure are the same as the conditions shown in FIG. As shown in FIG. 7B, in addition to the peak position in the TM mode shown in FIG. 2, a peak position matching the peak position in the TE mode shown in FIG. 6 was also observed. This result shows that the TE mode is also converted and output by diffraction due to the two-dimensional periodic structure. Further, regarding the two-dimensional periodic structure, it is necessary to consider diffraction satisfying the first-order diffraction condition at the same time in both the x direction and the y direction. Such diffracted light is emitted in the direction of the angle corresponding to the period of √2 times the period p (that is, 2 ^1/2 times). Therefore, in addition to the peak in the case of the one-dimensional periodic structure, it is considered that the peak also occurs in the period of √2 times the period p. Such a peak can also be confirmed in FIG. 7B.

The two-dimensional periodic structure is not limited to the structure of a square lattice having the same period in the x direction and the y direction as shown in FIG. 7A, but a lattice structure in which hexagons and triangles are arranged as shown in FIGS. 18A and 18B. Good. Further, the structure may have different periods depending on the azimuth direction (for example, the x direction and the y direction in the case of a square lattice).

As described above, in the present embodiment, the light of the characteristic pseudo-waveguide mode formed by the periodic structure and the photoluminescence layer is selectively emitted only in the front direction by utilizing the diffraction phenomenon by the periodic structure. I confirmed that I could do it. With such a structure, the photoluminescence layer is excited with excitation light such as ultraviolet rays or blue light, whereby light emission having directivity can be obtained.

[5. Examination of periodic structure and structure of photoluminescence layer]
Next, the effect of changing various conditions such as the periodic structure, the structure of the photoluminescent layer, and the refractive index will be described.

[5-1. Refractive index of periodic structure]
First, the refractive index of the periodic structure was examined. The thickness of the photoluminescence layer is 200 nm, the refractive index of the photoluminescence layer is n _wav =1.8, and the surface structure is a uniform one-dimensional periodic structure in the y direction as shown in FIG. 1A, and the height is 50 nm and the period is The calculation was performed on the assumption that the wavelength was 400 nm and the polarization of light was the TM mode having an electric field component parallel to the y direction. FIG. 8 shows the result of calculation of the enhancement factor of the light output in the front direction by changing the emission wavelength and the refractive index of the periodic structure. Further, FIG. 9 shows the result when the thickness of the photoluminescent layer was set to 1000 nm under the same conditions.

First, focusing on the thickness of the photoluminescent layer, the light intensity with respect to the change in the refractive index of the periodic structure is more increased when the thickness is 1000 nm (FIG. 9) than when the thickness is 200 nm (FIG. 8). It can be seen that the shift of the peak wavelength (referred to as peak wavelength) is small. This is because as the thickness of the photoluminescence layer is smaller, the pseudo-waveguide mode is more susceptible to the refractive index of the periodic structure. That is, the higher the refractive index of the periodic structure, the larger the effective refractive index, and the peak wavelength shifts to the longer wavelength side by that amount, but this effect becomes more remarkable as the thickness of the photoluminescent layer becomes smaller. The effective refractive index is determined by the refractive index of the medium existing in the region where the electric field of the pseudo waveguide mode is distributed.

Next, focusing on the change in the peak with respect to the change in the refractive index of the periodic structure, it can be seen that the higher the refractive index, the wider the peak and the lower the intensity. This is because the higher the refractive index of the periodic structure is, the higher the rate of radiating the light of the pseudo-guided mode to the outside is, so that the effect of confining the light is reduced, that is, the Q value is lowered. In order to keep the peak intensity high, it is only necessary to use a pseudo-guided mode that has a high light confining effect (that is, a high Q value) to appropriately emit light to the outside. In order to realize this, it can be seen that it is advantageous to use a material whose refractive index is not too large as compared with the refractive index of the photoluminescent layer for the periodic structure. Therefore, in order to increase the peak intensity and the Q value to some extent, the refractive index of the dielectric material (that is, the light-transmitting layer) forming the periodic structure may be equal to or less than the refractive index of the photoluminescence layer. The same applies when the photoluminescent layer contains a material other than the photoluminescent material.

[5-2. Height of periodic structure]
Next, the height of the periodic structure was examined. The thickness of the photoluminescent layer is 1000 nm, the refractive index of the photoluminescent layer is n _wav =1.8, and the surface structure is a uniform one-dimensional periodic structure in the y direction as shown in FIG. 1A, and the refractive index is n _p =1. 5. The calculation was performed assuming that the period was 400 nm and the polarization of light was the TM mode having an electric field component parallel to the y direction. FIG. 10 shows the result of calculation of the enhancement factor of the light output in the front direction by changing the emission wavelength and the height of the periodic structure. FIG. 11 shows the calculation result when the refractive index of the periodic structure is n _p =2.0 under the same conditions. In the result shown in FIG. 10, the peak intensity and Q value (that is, the line width of the peak) do not change at a certain height or higher, whereas in the result shown in FIG. 11, the height of the periodic structure is large. It can be seen that the peak intensity and the Q value are lowered more. This is because when the refractive index n _{wav of the} photoluminescent layer is higher than the refractive index n _{p of the} periodic structure (FIG. 10 ), light is totally reflected, so that the electric field (evanescent) portion of the pseudo-guided mode is extruded. Only due to the interaction with the periodic structure. The effect of the interaction between the evanescent part of the electric field and the periodic structure is constant if the height of the periodic structure is sufficiently large, even if the height changes further. On the other hand, when the refractive index n _{wav of the} photoluminescence layer is lower than the refractive index n _{p of the} periodic structure (FIG. 11), light reaches the surface of the periodic structure without being totally reflected, and therefore the height of the periodic structure is high. The larger is, the more affected it is. As can be seen from FIG. 11, it is sufficient that the height is about 100 nm, and the peak intensity and the Q value are lowered in the region exceeding 150 nm. Therefore, when the refractive index n _{wav of the} photoluminescent layer is lower than the refractive index n _p of the periodic structure, the height of the periodic structure may be set to 150 nm or less in order to increase the peak intensity and the Q value to some extent.

[5-3. Polarization direction]
Next, the polarization direction was examined. FIG. 12 shows the result of calculation under the same conditions as the calculation shown in FIG. 9, assuming that the polarization of light is the TE mode having an electric field component perpendicular to the y direction. In the TE mode, the seepage of the electric field in the pseudo-guided mode is larger than that in the TM mode, so that it is easily affected by the periodic structure. Therefore, in the region where the refractive index n _p of the periodic structure is larger than the refractive index n _{wav of the} photoluminescent layer, the peak intensity and the Q value decrease more significantly than the TM mode.

[5-4. Refractive index of photoluminescence layer]
Next, the refractive index of the photoluminescent layer was examined. FIG. 13 shows the result when the refractive index n _wav of the photoluminescence layer was changed to 1.5 under the same condition as the calculation shown in FIG. It can be seen that even when the refractive index n _{wav of the} photoluminescence layer is 1.5, the same effect as in FIG. 9 is obtained. However, it can be seen that light having a wavelength of 600 nm or more is not emitted in the front direction. This is because from the formula (10), λ ₀ <n _wav ×p/m=1.5×400 nm/1=600 nm.

From the above analysis, the refractive index of the periodic structure should be equal to or lower than the refractive index of the photoluminescent layer, or if the refractive index of the periodic structure is equal to or higher than the refractive index of the photoluminescent layer, the height should be 150 nm or less. It can be seen that the peak intensity and the Q value can be increased.

[6. Modification]
Hereinafter, modified examples of the embodiment of the light emitting element will be described.

[6-1. Configuration with substrate]
The light emitting device may have a structure in which a photoluminescent layer 110 and a surface structure 120 are formed on a transparent substrate 140, as shown in FIGS. 1C and 1D. In order to manufacture such a light emitting device 100a, first, a thin film is formed on the transparent substrate 140 with a photoluminescent material (including a matrix material, if necessary, the same applies hereinafter) forming the photoluminescent layer 110. , A method of forming the surface structure 120 thereon can be considered. In such a configuration, in order for the photoluminescence layer 110 and the surface structure 120 to have the function of emitting light in a specific direction, the refractive index n _s of the transparent substrate 140 is equal to or less than the refractive index n _{wav of the} photoluminescence layer. Need to When the transparent substrate 140 is provided so as to be in contact with the photoluminescent layer 110, the period p may be set so as to satisfy the equation (15) in which the refractive index n _out of the emission medium in the equation (10) is n _s .

In order to confirm this, calculation was performed when the photoluminescent layer 110 and the surface structure 120 were provided on the transparent substrate 140 having a refractive index of 1.5 under the same conditions as the calculation shown in FIG. The result of this calculation is shown in FIG. Similar to the result of FIG. 2, it can be confirmed that the peak of the light intensity appears in a specific cycle for each wavelength, but it can be seen that the range of the cycle in which the peak appears is different from the result of FIG. On the other hand, FIG. 15 shows the condition of the formula (15) where the condition of the formula (10) is n _out =n _s . In FIG. 14, it can be seen that the peak of the light intensity appears in the area corresponding to the range shown in FIG.

Therefore, in the light emitting device 100a in which the photoluminescent layer 110 and the surface structure 120 are provided on the transparent substrate 140, the effect is obtained in the range of the period p satisfying the expression (15), and the period p satisfying the expression (13) is obtained. A particularly remarkable effect is obtained in the range of.

[6-2. Light emitting device having excitation light source]
FIG. 16 is a diagram showing a configuration example of a light emitting device 200 including the light emitting element 100 shown in FIGS. 1A and 1B and a light source 180 for making excitation light incident on the photoluminescence layer 110. As described above, in the configuration of the present disclosure, directional light emission is obtained by exciting the photoluminescence layer with excitation light such as ultraviolet light or blue light. By providing the light source 180 configured to emit such excitation light, the light emitting device 200 having directivity can be realized. The wavelength of the excitation light emitted from the light source 180 is typically a wavelength in the ultraviolet or blue region, but is not limited to this, and is appropriately determined according to the photoluminescent material forming the photoluminescent layer 110. Note that, in FIG. 16, the light source 180 is arranged so that the excitation light is incident from the lower surface of the photoluminescence layer 110, but the present invention is not limited to this example, and for example, the excitation light is emitted from the upper surface of the photoluminescence layer 110. It may be incident. The excitation light may be incident from a direction inclined (that is, obliquely) with respect to a direction perpendicular to the main surface (that is, the upper surface or the lower surface) of the photoluminescent layer 110. By making the excitation light obliquely incident at an angle at which total reflection occurs in the photoluminescence layer 110, the photoluminescence layer 110 can be caused to emit light more efficiently.

There is also a method of efficiently emitting light by coupling the excitation light to the pseudo waveguide mode. 17A to 17D are diagrams for explaining such a method. In this example, the photoluminescent layer 110 and the surface structure 120 are formed on the transparent substrate 140, as in the configurations shown in FIGS. 1C and 1D. First, as shown in FIG. 17A, a period p _x in the x direction is determined for emission enhancement, and subsequently, as shown in FIG. 17B, a period in the y direction for coupling excitation light into a pseudo-guided mode. to determine the p _y. The period p _x is determined so as to satisfy the condition that p is replaced with p _x in the equation (10). On the other hand, for the period _py , m is an integer of 1 or more, the wavelength of the excitation light is λ _ex , and the refractive index of the medium having the highest refractive index excluding the surface structure 120 among the media in contact with the photoluminescent layer 110 is n _out , It is determined so as to satisfy the following expression (16).

Here, n _out is n _s of the transparent substrate 140 in the example of FIG. 17B, but is the refractive index of air (about 1.0) in the configuration in which the transparent substrate 140 is not provided as in FIG.

In particular, if m=1 and the period _py is determined so as to satisfy the following expression (17), the effect of converting the excitation light into the pseudo waveguide mode can be further enhanced.

In this way, by setting the period p _y so as to satisfy the condition (in particular the condition of equation (17)) of formula (16) can be converted excitation light to the pseudo guided mode. As a result, the photoluminescence layer 110 can efficiently absorb the excitation light of the wavelength λ _ex .

FIG. 17C and FIG. 17D are diagrams showing the results of calculating the ratio of light absorption for each wavelength when light is incident on the structures shown in FIGS. 17A and 17B, respectively. In this calculation, p _x =365 nm, p _y =265 nm, the emission wavelength λ from the photoluminescence layer 110 is about 600 nm, the wavelength λ _{ex of the} excitation light is about 450 nm, and the extinction coefficient of the photoluminescence layer 110 is 0.003. I am trying. As shown in FIG. 17D, a high absorptivity is exhibited not only for light generated from the photoluminescence layer 110 but also for excitation light of about 450 nm. This is because the incident light is effectively converted into the pseudo-guided mode, so that the ratio of absorption in the photoluminescence layer can be increased. In addition, the absorptance also increases with respect to the emission wavelength of about 600 nm. This means that if light with a wavelength of about 600 nm is incident on this structure, the pseudo-guided mode is also effective. Is to be converted to.

The surface structure 120 shown in FIG. 17B is a two-dimensional periodic structure having a structure (referred to as a periodic component) having a different period in each of the x direction and the y direction. As described above, by using the two-dimensional periodic structure having a plurality of periodic components, it is possible to enhance the emission efficiency while enhancing the excitation efficiency. Although the excitation light is incident from the substrate 140 side in FIGS. 17A and 17B, the same effect can be obtained even when the excitation light is incident from the surface structure 120 side.

Furthermore, as a two-dimensional periodic structure having a plurality of periodic components, a configuration as shown in FIG. 18A or 18B may be adopted. A configuration in which a plurality of convex portions or concave portions having a hexagonal planar shape are periodically arranged as shown in FIG. 18A, or a plurality of convex portions or concave portions having a triangular planar shape are periodically arranged as shown in FIG. 18B. With the side-by-side configuration, a plurality of main axes (axis 1 to 3 in the illustrated example) that can be regarded as a cycle can be defined. Therefore, different periods can be assigned to the respective axial directions. Each of these cycles may be set to enhance the directivity of light of a plurality of wavelengths, or may be set to efficiently absorb the excitation light. In any case, each cycle is set so as to satisfy the condition corresponding to the equation (10).

[6-3. Periodic structure on transparent substrate]
As shown in FIGS. 19A and 19B, the surface structure 120a may be formed on the transparent substrate 140, and the photoluminescence layer 110 may be provided thereon. In the configuration example of FIG. 19A, the photoluminescence layer 110 is formed so as to follow the surface structure 120a formed of the unevenness on the substrate 140. As a result, the surface structure 120b having the same period is also formed on the surface of the photoluminescence layer 110. On the other hand, in the configuration example of FIG. 19B, the surface of the photoluminescence layer 110 is flattened. Also in these configuration examples, directional light emission can be realized by setting the period p of the surface structure 120a so as to satisfy the expression (15).

In order to verify this effect, in the configuration of FIG. 19A, the emission wavelength and the period of the periodic structure were changed, and the enhancement of the light output in the front direction was calculated. Here, the thickness of the photoluminescence layer 110 is 1000 nm, the refractive index of the photoluminescence layer 110 is n _wav =1.8, and the surface structure 120a is a uniform one-dimensional periodic structure in the y direction, and its height is 50 nm. The refractive index was n _p =1.5, the period was 400 nm, and the polarization of light was the TM mode having an electric field component parallel to the y direction. The result of this calculation is shown in FIG. 19C. Also in this calculation, peaks of light intensity were observed in a cycle that satisfied the condition of Expression (15).

[6-4. powder]
According to the embodiment as described above, it is possible to enhance the emission of light of an arbitrary wavelength by adjusting the period of the periodic structure, the thickness of the photoluminescence layer, and the like. For example, if a photoluminescence material that emits light in a wide band is used and the structure shown in FIGS. 1A and 1B is used, it is possible to emphasize only light of a certain wavelength. Therefore, the structure of the light emitting device 100 as shown in FIGS. 1A and 1B may be powdered and used as a fluorescent material. Alternatively, the light emitting device 100 as shown in FIGS. 1A and 1B may be embedded in resin or glass and used.

With a single structure as shown in FIGS. 1A and 1B, only certain wavelengths can be emitted in a certain direction, so it is difficult to realize white light emission having a spectrum in a wide wavelength range. Therefore, as shown in FIG. 20, by using a mixture in which a plurality of powdery light emitting elements 100 having different conditions such as the period of the periodic structure and the thickness of the photoluminescence layer are mixed, light emission having a spectrum of a wide wavelength range is obtained. The device can be realized. In this case, the size of each light emitting element 100 in one direction is, for example, about several μm to several mm, and may include, for example, a one-dimensional or two-dimensional periodic structure of several cycles to several hundred cycles.

[6-5. Arrange structures with different periods]
FIG. 21 is a plan view showing an example in which a plurality of periodic structures having different periods are two-dimensionally arranged on the photoluminescent layer. In the light emitting device 100c illustrated in FIG. 21, three types of surface structures 120a, 120b, 120c are arranged without a gap. For example, the surface structures 120a, 120b, 120c have a cycle set to emit light in the red, green, and blue wavelength ranges to the front, respectively. As described above, by arranging a plurality of structures having different periods on the photoluminescence layer, directivity can be exerted with respect to the spectrum in a wide wavelength range. The configuration of the plurality of periodic structures is not limited to the above and may be set arbitrarily.

[6-6. Laminated structure]
FIG. 22 shows an example of a light emitting element having a structure in which a plurality of photoluminescent layers 110 having an uneven structure formed on the surface thereof are laminated. A transparent substrate 140 is provided between the plurality of photoluminescent layers 110, and the concavo-convex structure formed on the surface of the photoluminescent layer 110 of each layer corresponds to the above periodic structure or submicron structure. In the example shown in FIG. 22, three layers of periodic structures having different periods are formed, and the periods are set so that lights in the red, blue, and green wavelength ranges are emitted to the front, respectively. Further, the material of the photoluminescence layer 110 of each layer is selected so as to emit light of a color corresponding to the period of each periodic structure. As described above, by stacking a plurality of periodic structures having different periods, directivity can be exerted on the spectrum in a wide wavelength range.

Note that the number of layers, the photoluminescence layer 110 of each layer, and the structure of the periodic structure are not limited to the above, and may be set arbitrarily. For example, in the case of a two-layer structure, the first photoluminescent layer and the second photoluminescent layer are formed to face each other with the light-transmitting substrate interposed therebetween, and on the surfaces of the first and second photoluminescent layers, First and second periodic structures are formed, respectively. In this case, for each of the pair of the first photoluminescent layer and the first periodic structure and the pair of the second photoluminescent layer and the second periodic structure, the condition corresponding to Expression (15) should be satisfied. Good. Similarly, in the structure having three or more layers, the photoluminescence layer and the periodic structure in each layer may satisfy the condition corresponding to Expression (15). The positional relationship between the photoluminescent layer and the periodic structure may be reversed from the example shown in FIG. In the example shown in FIG. 22, the periods of the layers are different, but they may all have the same period. In that case, although the spectrum cannot be widened, the emission intensity can be increased.

[6-7. Configuration Having Protective Layer]
FIG. 23 is a cross-sectional view showing a configuration example in which the protective layer 150 is provided between the photoluminescent layer 110 and the surface structure 120. As described above, the protective layer 150 for protecting the photoluminescent layer 110 may be provided. However, when the refractive index of the protective layer 150 is lower than the refractive index of the photoluminescent layer 110, the electric field of light leaks into the protective layer 150 for only about half the wavelength. Therefore, when the thickness of the protective layer 150 is larger than the wavelength, the light does not reach the surface structure 120. Therefore, there is no pseudo-guided mode, and the function of emitting light in a specific direction cannot be obtained. When the refractive index of the protective layer 150 is equal to or higher than the refractive index of the photoluminescent layer 110, the light reaches the inside of the protective layer 150. Therefore, there is no restriction on the thickness of the protective layer 150. However, even in such a case, a larger light output can be obtained by forming most of a portion where light is guided (hereinafter, this portion is referred to as a “waveguide layer”) with a photoluminescent material. Therefore, even in this case, it is advantageous that the protective layer 150 is thin. The protective layer 150 may be formed using the same material as the surface structure (or the light transmitting layer) 120. At this time, the light-transmitting layer having a periodic structure also serves as a protective layer. Advantageously, the refractive index of the transparent layer 120 is smaller than that of the photoluminescent layer 110.

[7. material]
If the photoluminescence layer (or the waveguiding layer) and the surface structure are made of materials satisfying the above conditions, directional light emission can be realized. Any material can be used for the surface structure. However, if the medium forming the photoluminescence layer (or the waveguide layer) or the surface structure has high light absorption, the effect of confining light is reduced, and the peak intensity and Q value are reduced. Therefore, as the medium forming the photoluminescence layer (or the waveguide layer) and the surface structure, a material having a relatively low light absorption property can be used.

As the material of the surface structure, for example, a dielectric material having low light absorption can be used. As a candidate for the material of the periodic structure, for example, MgF ₂ (magnesium fluoride), LiF (lithium fluoride), CaF ₂ (calcium fluoride), SiO ₂ (quartz), glass, resin, MgO (magnesium oxide), ITO (indium tin oxide), TiO ₂ (titanium oxide), SiN (silicon nitride), Ta ₂ O ₅ (tantalum pentoxide), ZrO ₂ (zirconia), ZnSe (zinc selenide), ZnS (zinc sulfide), etc. Can be mentioned. However, as described above, when the refractive index of the surface structure is made lower than that of the photoluminescent layer, the refractive index is about 1.3 to 1.5 such as MgF ₂ , LiF, CaF ₂ , SiO ₂ , glass, and resin. Can be used.

Photoluminescent materials include fluorescent materials and phosphorescent materials in a narrow sense, include not only inorganic materials but also organic materials (for example, dyes), and further include quantum dots (for example, semiconductor fine particles). Generally, a fluorescent material having an inorganic material as a host tends to have a high refractive index. Examples of the fluorescent material that emits blue light include M ₁₀ (PO ₄ ) ₆ Cl ₂ :Eu ²⁺ (M=at least one selected from Ba, Sr, and Ca), BaMgAl ₁₀ O ₁₇ :Eu ²⁺ , M ₃ MgSi ₂ O ₈ :Eu ²⁺ (at least one selected from M=Ba, Sr and Ca), M ₅ SiO ₄ Cl ₆ :Eu ²⁺ (at least one selected from M=Ba, Sr and Ca) Can be used. Examples of the fluorescent material that emits green light include M ₂ MgSi ₂ O ₇ :Eu ²⁺ (M=Ba, at least one selected from Sr and Ca), SrSi ₅ AlO ₂ N ₇ :Eu ²⁺ , SrSi ₂ O ₂ N ₂ :Eu ²⁺ , BaAl ₂ O ₄ :Eu ²⁺ , BaZrSi ₃ O ₉ :Eu ²⁺ , M ₂ SiO ₄ :Eu ²⁺ (M=at least one selected from Ba, Sr and Ca) _{, BaSi 3 O 4 n 2:} Eu 2+ Ca 8 Mg (SiO 4) 4 Cl 2: Eu 2+, Ca 3 SiO 4 Cl 2: Eu 2+, CaSi 12- (m + n) Al (m + n _{) O n n 16-n:} Ce 3+, β-SiAlON: Eu 2+ can be used. Examples of the fluorescent material that emits red light include CaAlSiN ₃ :Eu ²⁺ , SrAlSi ₄ O ₇ :Eu ²⁺ , M ₂ Si ₅ N ₈ :Eu ²⁺ (M=Ba, Sr, and at least 1 selected from Ca). Seed), MSiN ₂ :Eu ²⁺ (at least one selected from M=Ba, Sr and Ca), MSi ₂ O ₂ N ₂ :Yb ²⁺ (at least one selected from M=Sr and Ca), Y ₂ O ₂ S: Eu ³⁺ , Sm ³⁺ , La ₂ O ₂ S: Eu ³⁺ , Sm ³⁺ , CaWO ₄ : Li ¹⁺ , Eu ³⁺ , Sm ³⁺ , M ₂ SiS ₄ :Eu ²⁺ (At least one selected from M=Ba, Sr and Ca) and M ₃ SiO ₅ :Eu ²⁺ (at least one selected from M=Ba, Sr and Ca) can be used. Examples of the fluorescent material that emits yellow light include Y ₃ Al ₅ O ₁₂ :Ce ³⁺ , CaSi ₂ O ₂ N ₂ :Eu ²⁺ , Ca ₃ Sc ₂ Si ₃ O ₁₂ :Ce ³⁺ , and CaSc ₂ O _4. : Ce ³⁺ , α-SiAlON:Eu ²⁺ , MSi ₂ O ₂ N ₂ :Eu ²⁺ (at least one selected from M=Ba, Sr and Ca), M ₇ (SiO ₃ ) ₆ Cl ₂ :Eu ²⁺ (M=at least one selected from Ba, Sr and Ca) can be used.

For the quantum dots, materials such as CdS, CdSe, core/shell type CdSe/ZnS, and alloy type CdSSe/ZnS can be used, and various emission wavelengths can be obtained depending on the material. As the matrix of quantum dots, for example, glass or resin can be used.

The substrate 140 shown in FIG. 1C, FIG. 1D, etc. is made of a translucent material having a refractive index lower than that of the photoluminescence layer 110. Examples of such a material include MgF ₂ (magnesium fluoride), LiF (lithium fluoride), CaF ₂ (calcium fluoride), SiO ₂ (quartz), glass, and resin. It is not essential that the substrate 140 be transparent in the configuration in which the excitation light is incident on the photoluminescence layer 110 without passing through the substrate 140. The substrate 140 is, for example, BaF ₂ , SrF ₂ , MgO, MgAl ₂ O ₄ , sapphire (Al ₂ O ₃ ), SrTiO ₃ , LaAlO ₃ , TiO ₂ , Gd ₃ Ga ₅ O ₁₂ , LaSrAlO ₄ , LaSrGaO ₄ , LaTaO. ₃ , SrO, YSZ (ZrO ₂ ·Y ₂ O ₃ ), YAG, and Tb ₃ Ga ₅ O ₁₂ may be used.

[8. Production method]
Next, an example of a method for manufacturing the light emitting element will be described.

As a method of realizing the configuration shown in FIGS. 1C and 1D, for example, a thin film of the photoluminescent layer 110 is formed by depositing a fluorescent material on the transparent substrate 140 by vapor deposition, sputtering, coating, or the like, and then a dielectric is formed. There is a method of forming the surface structure 120 by forming a film and patterning it by a method such as photolithography. As an alternative to the above method, the surface structure 120 may be formed by nanoimprint. Further, as shown in FIG. 24, the surface structure 120 may be formed by processing a part of the photoluminescence layer 110. In that case, the surface structure 120 is formed of the same material as the photoluminescent layer 110.

The light-emitting element 100 shown in FIGS. 1A and 1B is realized by, for example, manufacturing the light-emitting element 100a shown in FIGS. 1C and 1D and then performing a step of peeling off the photoluminescent layer 110 and the surface structure 120 from the substrate 140. It is possible.

In the structure shown in FIG. 19A, for example, after the surface structure 120a is formed on the transparent substrate 140 by a method such as a semiconductor process or nanoimprinting, a material forming the photoluminescent layer 110 is formed thereon by a method such as vapor deposition or sputtering. It can be realized by Alternatively, the structure shown in FIG. 19B can be realized by filling the concave portion of the surface structure 120a with the photoluminescent layer 110 using a method such as coating.

Note that the above manufacturing method is an example, and the light emitting element of the present disclosure is not limited to the above manufacturing method.

[9. Experimental example]
Hereinafter, an example of manufacturing a light emitting element applicable to the light emitting device according to the embodiment of the present disclosure will be described.

A sample of a light emitting device having the same structure as that of FIG. 19A was manufactured as a prototype and its characteristics were evaluated. The light emitting device was manufactured as follows.

A one-dimensional periodic structure (striped convex portion) having a period of 400 nm and a height of 40 nm was provided on a glass substrate, and YAG:Ce, which is a photoluminescent material, was deposited on the one-dimensional periodic structure to form a film having a thickness of 210 nm. FIG. 25 shows a TEM image of this cross-sectional view, and FIG. 26 shows the result of measuring the spectrum in the front direction when YAG:Ce was made to emit light by exciting this with a 450 nm LED. FIG. 26 shows the measurement result (ref) when there is no periodic structure, the measurement result for the TM mode having a polarization component parallel to the one-dimensional periodic structure, and the measurement result for the TE mode having a vertical polarization component. showed that. When the periodic structure is provided, the light having a specific wavelength is significantly increased as compared with the case where the periodic structure is not provided. Further, it is understood that the TM mode having a polarization component parallel to the one-dimensional periodic structure has a larger light enhancement effect.

Further, in the same sample, the measurement result and the calculation result of the angle dependence of the emitted light intensity are shown in FIGS. 27A to 27F and 28A to 28F. FIG. 27A shows a situation in which a light emitting element that emits TM-mode linearly polarized light is rotated about an axis parallel to the line direction of the one-dimensional periodic structure 120 as a rotation axis. FIG. 27B and FIG. 27C respectively show the measurement result and the calculation result in the case of such rotation. On the other hand, FIG. 27D shows a situation in which the light emitting element that emits TE mode linearly polarized light is rotated about an axis parallel to the line direction of the one-dimensional periodic structure 120 as a rotation axis. 27E and 27F show the measurement result and the calculation result in this case, respectively. FIG. 28A shows a situation in which a light emitting element that emits TE-mode linearly polarized light is rotated about an axis perpendicular to the line direction of the one-dimensional periodic structure 120 as a rotation axis. 28B and 28C show the measurement result and the calculation result in this case, respectively. On the other hand, FIG. 28D shows a situation in which a light emitting element that emits TM-mode linearly polarized light is rotated about an axis perpendicular to the line direction of the one-dimensional periodic structure 120 as a rotation axis. 28E and 28F show the measurement result and the calculation result in this case, respectively.

As apparent from FIGS. 27A to 27F and FIGS. 28A to 28F, the TM mode has a higher effect of being enhanced. Also, it can be seen that the wavelength of the enhanced light shifts depending on the angle. For example, with respect to the light having the wavelength of 610 nm, it is understood that the light is in the TM mode and only in the front direction, so that the directivity is high and the polarized light is emitted. 27B and FIG. 27C, FIG. 27E and FIG. 27F, FIG. 28B and FIG. 28C, and FIG. 28E and FIG. Backed by

FIG. 29 shows the angular dependence of the intensity of light with a wavelength of 610 nm when rotated about a direction perpendicular to the line direction as a rotation axis, as shown in FIG. 28D. It can be seen that strong emission enhancement occurs in the front direction, and light is hardly enhanced at other angles. Further, it can be seen that the directivity angle of the light emitted in the front direction is less than 15°. As described above, the directivity angle is an angle at which the intensity is 50% of the maximum intensity, and is represented by an angle on one side with the direction of the maximum intensity as the center. From the results shown in FIG. 29, it can be seen that directional light emission is realized. Further, it can be seen that all the emitted light is a TM mode component, so that polarized light emission is also realized at the same time.

The above experiment for verification was performed using YAG:Ce that emits light in a wide wavelength band. Even if an experiment is performed using a photoluminescent material that emits light in a narrow band with the same configuration, it is possible to realize high directivity and polarized light emission for light of that wavelength. Furthermore, when such a photoluminescent material is used, a light source that does not generate light of other wavelengths and thus does not generate light of other directions or polarization states can be realized.

[10. Other modifications]
As described above, due to the submicron structure of the light emitting device according to the present disclosure, the wavelength and emission direction of light that undergoes the emission enhancement effect depend on the configuration of the submicron structure. Consider a light emitting device having a surface structure 120 on the photoluminescent layer 110 shown in FIG. Here, the case where the surface structure 120 is formed of the same material as the photoluminescent layer 110 and has the one-dimensional periodic structure shown in FIG. 1A is illustrated. The light whose emission is enhanced by the one-dimensional periodic structure has a period of the one-dimensional periodic structure of p (nm), the refractive index of the photoluminescent layer 110 is n _wav , and the refractive index of the external medium from which the light is emitted is n _out. When the incident angle to the one-dimensional periodic structure is θ _wav and the outgoing angle from the one-dimensional periodic structure to the external medium is θ _out , the relation of p×n _wav ×sin θ _wav −p×n _out ×sin θ _out =mλ Is satisfied (see the above equation (5)). Here, λ is the wavelength of light in the air, and m is an integer.

From the above equation, θ _out =arcsin [(n _wav ×sin θ _wav −mλ/p)/n _out ] is obtained. Therefore, generally, when the wavelength λ is different, the emission angle θ _{out of the} light subjected to the emission enhancement is different. As a result, as schematically shown in FIG. 31, the color of visible light varies depending on the viewing direction.

In order to reduce the viewing angle dependency, n _wav and n _out may be selected so that (n _wav ×sin θ _wav −mλ/p)/n _out is constant regardless of the wavelength λ. Since the refractive index of a substance has wavelength dispersion (wavelength dependence), the wavelengths of n _wav and n _out are such that (n _wav ×sin θ _wav −mλ/p)/n _out does not depend on the wavelength λ. A material having dispersibility may be selected. For example, when the external medium is air, n _out is approximately 1.0 regardless of the wavelength. Therefore, as the material forming the photoluminescence layer 110 and the one-dimensional periodic structure, a material having a small wavelength dispersion with a refractive index n _wav is used. Just select it. Further, an inverse dispersion material may be used which has a lower refractive index n _wav for light having a shorter wavelength.

Further, as shown in FIG. 32A, it is possible to emit white light by arranging a plurality of periodic structures having mutually different wavelengths which have a light emission enhancing effect. In the example shown in FIG. 32A, a surface structure 120r capable of enhancing red light (R), a surface structure 120g capable of enhancing green light (G), and a surface structure 120b capable of enhancing blue light (B) are arranged in a matrix. Has been done. The surface structures 120r, 120g, and 120b are, for example, one-dimensional periodic structures, and the respective convex portions are arranged in parallel with each other. Therefore, in this example, the polarization characteristics are the same for light of all colors red, green and blue. The surface structures 120r, 120g, and 120b emit light of the three primary colors that have undergone emission enhancement and are mixed, so that white light and linearly polarized light are obtained.

When the surface structures 120r, 120g, and 120b arranged in a matrix are referred to as a unit periodic structure (or pixel), the size of the unit periodic structure (that is, the length of one side) is, for example, three times or more the period. is there. Further, in order to obtain the effect of color mixing, it is useful if the unit periodic structure is not recognized by human eyes, and for example, the length of one side is smaller than 1 mm. Here, each unit periodic structure is drawn as a square, but the present invention is not limited to this. For example, the surface structures 120r, 120g, and 120b adjacent to each other may have a shape other than a square, such as a rectangle, a triangle, or a hexagon.

The photoluminescence layer provided under the surface structures 120r, 120g, and 120b may be common to the surface structures 120r, 120g, and 120b, or different photoluminescence layers may be used depending on the light of each color. A photoluminescent layer having a material may be provided.

As shown in FIG. 32B, a plurality of periodic structures (including surface structures 120h, 120i, and 120j) having different azimuths in which the convex portions of the one-dimensional periodic structure extend may be arranged. The wavelengths of light emitted by the plurality of periodic structures may be the same or different. For example, when the same periodic structure is arranged as shown in FIG. 32B, unpolarized light can be obtained. When the arrangement of FIG. 32B is applied to each of the surface structures 120r, 120g, and 120b in FIG. 32A, unpolarized white light can be obtained as a whole.

Of course, the periodic structure applied to the tiling is not limited to the one-dimensional periodic structure, and as shown in FIG. 32C, for example, a plurality of two-dimensional periodic structures (including surface structures 120k, 120m and 120n) may be arranged. .. At this time, the periods and the azimuths of the surface structures 120k, 120m, and 120n may be the same as or different from each other as described above, and can be appropriately set as necessary.

As shown in FIG. 33, for example, an array of microlenses 130 may be arranged on the light emitting side of the light emitting element. The array of the microlenses 130 can obtain the effect of color mixing by bending the light emitted in the oblique direction in the normal direction.

The light emitting device shown in FIG. 33 has regions R1, R2 and R3 having the surface structures 120r, 120g and 120b in FIG. 32A, respectively. In the region R1, the surface structure 120r causes the red light R to be emitted in the normal direction and, for example, the green light G to be emitted in an oblique direction. Due to the refraction of the microlens 130, the green light G emitted in the oblique direction is bent in the normal direction. As a result, in the normal direction, the red light R and the green light G are mixed and observed. As described above, by providing the microlens 130, the phenomenon that the wavelength of the emitted light varies depending on the angle is suppressed. Here, a microlens array in which a plurality of microlenses corresponding to a plurality of periodic structures are integrated is illustrated, but the present invention is not limited to this. Of course, the periodic structure to be tiled is not limited to the above example, and can be applied to the case where the same periodic structure is tiled, or can be applied to the configuration shown in FIG. 32B or 32C.

The optical element having a function of bending the light emitted in the oblique direction may be a lenticular lens instead of the microlens array. Further, not only a lens but also a prism can be used. An array of prisms may be used. You may arrange|position a prism individually corresponding to a periodic structure. The shape of the prism is not particularly limited. For example, a triangular prism or a pyramid prism can be used.

As a method of obtaining white light (or light having a wide spectrum width), a method of using two or more photoluminescence layers as described with reference to FIG. 34A and FIG. There is also. As shown in FIG. 34A, white light can be obtained by stacking a plurality of photoluminescent layers 110b, 110g, and 110r having different emission wavelengths. The stacking order is not limited to the illustrated example. In addition, as shown in FIG. 34B, a photoluminescent layer 110y that emits yellow light may be stacked on the photoluminescent layer 110b that emits blue light. The photoluminescence layer 110y can be formed using, for example, YAG.

In addition, in the case of using a photoluminescent material mixed with a matrix (host) material such as a fluorescent dye, a plurality of photoluminescent materials having different emission wavelengths are mixed with the matrix material, and a single photoluminescent layer is used. It can emit white light. Such a photoluminescence layer capable of emitting white light can be used in the configuration in which the unit periodic structure is tiled, which is described with reference to FIGS. 32A to 32C.

[11. Light Emitting Device Having Condensing Lens]
Hereinafter, an exemplary configuration of the light emitting device according to the embodiment of the present disclosure will be described. FIG. 35 schematically illustrates an exemplary configuration of the light emitting device according to the embodiment of the present disclosure. A light emitting device 210A shown in FIG. 35 schematically includes the light emitting device 200 described with reference to FIG. 16 and a condenser lens 202 that receives light emitted from the light emitting device 200. That is, the light emitting device 210A includes the excitation light source 180, the light emitting element 100, and the condenser lens 202.

The light emitting element 100 is arranged on the optical path along which the excitation light emitted from the excitation light source 180 travels. By disposing the light emitting element 100 on the optical path of the excitation light, the excitation light emitted from the excitation light source 180 enters the photoluminescent layer 110 of the light emitting element 100. The photoluminescent material in the photoluminescent layer 110 receives excitation light and emits light. The light emitted by the photoluminescence layer 110 is emitted to the outside of the light emitting element 100 via the surface structure 120 (see, for example, FIG. 16 ). As described above, the light emitting device 100 can emit light in a specific direction. In this example, light is emitted in the front direction of the light emitting element 100. Of course, instead of the light emitting element 100, the light emitting element 100a shown in FIGS. 1C and 1D may be applied.

The light emitted from the light emitting element 100 enters the condenser lens 202 facing the surface structure 120. In the configuration illustrated in FIG. 35, the condenser lens 202 is disposed on the optical path of the light emitted from the light emitting element 100 by being supported by the housing 300. The housing 300 may hold the light emitting element 100 and the condenser lens 202 in a state where they are positioned.

In the configuration illustrated in FIG. 35, an optical fiber 250 is connected to the light emitting device 210A. In this example, the housing 300 has an opening 300a provided at a position where the light emitted from the condenser lens 202 is incident, and the optical fiber 250 has one end inserted into the opening 300a. , Is fixed to the light emitting device 210A.

In a state where the optical fiber 250 is connected to the light emitting device 210A, one end of the optical fiber 250 is at a position where the light emitted from the condenser lens 202 is incident. Therefore, at least part of the light emitted from the condenser lens 202 enters the optical fiber 250. That is, the optical fiber 250 is optically coupled to the light emitting device 210A by being connected to the light emitting device 210A. As described above, in the configuration illustrated in FIG. 35, the opening portion 300a has a function as a connecting portion of the optical fiber 250. In this example, the optical axis of the condenser lens 202 and the axis of the optical fiber 250 are coincident with each other.

The structure for connecting the optical fibers is not limited to the structure shown in FIG. 35 as long as it can receive the incident portion of the optical fiber. A transparent member capable of transmitting the light emitted from the condenser lens 202 may be arranged in the opening 300a. The transparent member disposed in the opening 300a may have an antireflection coating. 210 A of light-emitting devices may have an optical connector, a socket, a slot, a plug, etc. as a connection part of an optical fiber in the position where the light radiate|emitted from the condensing lens 202 injects.

As described above, since the light emitting element 100 has a novel structure capable of controlling the directivity of emitted light, for example, the light generated from the photoluminescent layer 110 can be selectively emitted in the front direction. It is possible. Therefore, as schematically shown in FIG. 36, almost all of the outgoing light flux can be made incident on the condenser lens 202 without using a collimator lens or the like. In this way, since the light emitting element 100 can emit light with high directivity, according to the embodiment of the present disclosure, it is possible to improve the light utilization efficiency without using a large condenser lens. Therefore, a smaller light emitting device or optical device can be provided.

FIG. 37 shows a light emitting device 510 having a conventional phosphor 512 in place of the light emitting element 100 as a comparative example. Note that the housing 300 shown in FIG. 35 is omitted in FIG. 37 and FIG. 36 described above. Also in the following, illustration of the housing 300 may be omitted.

In the light emitting device 510, the phosphor 512 emits light isotropically. Therefore, the light flux emitted from the phosphor 512 contains a light flux that cannot be incident on the condenser lens 202 in principle. That is, the light generated in the phosphor 512 cannot be effectively used. For example, as schematically shown in FIG. 37, the ratio of the emitted light flux that enters the condenser lens 202 from the phosphor 512 may be about 20%. The remaining 80% of the luminous flux emitted from the phosphor 512 is loss.

For example, as shown in FIGS. 36 and 37, assume an optical system in which light emitted from a light source (here, the light emitting element 100 or the phosphor 512) is incident on the optical fiber 250. It is known that in an optical system, an amount called “Etendue” is preserved if there is no diffusion. For example, the etendue of a light source is defined by the product of the light emitting area of the light source and the solid angle of the light diverging from the light source. The etendue can also be defined as an irradiation surface that receives light from a light source, and the etendue on the light receiving side represents the size of the ability of taking in light on the light receiving side. If the etendue on the light receiving side is smaller than the etendue of the light source, it is not possible to capture all of the light emitted from the light source, resulting in loss. That is, when the etendue on the light source side is equal to the etendue of the optical fiber to be irradiated, it can be said that the light utilization efficiency is maximum. The etendue of the optical fiber 250 is determined by the numerical aperture of the optical fiber 250. If the etendue on the light source side is larger than the etendue of the optical fiber, loss occurs.

In the light emitting device 210A shown in FIG. 36, a condenser lens 202 having a focal length of an appropriate size is used according to the numerical aperture of the optical fiber 250, and the distance between the condenser lens 202 and the end surface of the optical fiber 250. By appropriately adjusting the above, almost all the light emitted from the condenser lens 202 can be made incident on the optical fiber 250. When the light emitting device 210A is provided with an optical fiber connecting portion, the arrangement between the light emitting device 210A and the optical fiber 250 can be fixed, and thus high coupling efficiency between the light emitting device 210A and the optical fiber 250 can be easily realized, which is useful. ..

On the other hand, in the configuration in which the conventional phosphor 512 is used instead of the light emitting element 100 (see FIG. 37), the phosphor 512 generally emits light isotropically, and therefore the phosphor 512 is generally used rather than the etendue of the optical fiber. , The etendue is larger, and thus a high coupling efficiency cannot be obtained between the phosphor 512 and the optical fiber 250. In the example shown in FIG. 37, the coupling efficiency between the phosphor 512 and the optical fiber 250 is only 20%. If the size of the etendue on the light receiving side is constant, the amount of light that can be introduced into the optical fiber 250 does not increase even if the light emitting area of the light source (here, the phosphor 512) is expanded. As described above, the etendue of the optical fiber 250 is determined by the numerical aperture of the optical fiber 250. Therefore, even if a lens having a larger diameter is simply applied in order to increase the luminous flux incident on the condenser lens 202, If the numerical aperture is the same, the number of light beams entering the optical fiber 250 will not be increased.

In the light emitting device 210A, almost all of the light flux emitted from the light emitting element 100 can be made incident on the condenser lens 202 (see FIG. 36). That is, almost all of the light emitted from the light emitting element 100 can be incident on the optical fiber 250. As described above, according to the embodiment of the present disclosure, the emission direction of the light from the light emitting element 100 can be controlled so as to enter the optical fiber 250 by passing through the condenser lens 202. The coupling efficiency between the light emitting device 100 and the optical fiber 250 may be improved.

According to the embodiment of the present disclosure, a high coupling efficiency can be realized between the light emitting device 100 and the optical fiber 250, and thus the amount of input energy required to obtain the same output (may be referred to as a light flux) from the optical fiber 250. Can be reduced. For example, it is assumed that a laser diode having a power conversion efficiency of 40% is used as the excitation light source 180 and an output of 2.3 W is obtained from the optical fiber 250. Assuming that the conversion efficiency of the phosphor is 55%, the amount of energy input to the excitation light source 180 at this time is about 53.9 W in the light emitting device 510 of the comparative example shown in FIG. 37. In the light emitting device 210A shown in FIG. 36, it is about 10.7 W. That is, energy saving of the light emitting device can be achieved.

35 to 37, the condenser lens 202 is shown as a biconvex lens. However, the condensing lens 202 is not limited to a biconvex lens, and may be a plano-convex lens, a Fresnel lens, or a grin lens having a refractive index that changes along the axis. The condenser lens 202 may be a lens coupled to the end face of the optical fiber.

[11-1. Modified Example of Light Emitting Device Having Condensing Lens]
FIG. 38 illustrates another modification of the light emitting device according to the embodiment of the present disclosure. A light emitting device 210B shown in FIG. 38 has a collimator lens 204 between the light emitting element 100 and the condenser lens 202. Since the directivity angle of the light emitted from the light emitting element 100 is relatively small, a high light utilization efficiency can be obtained even though a lens having a small diameter is used as the collimator lens 208. Further, according to such a configuration, the distance from the light emitting element 100 to the connecting portion of the optical fiber 250 can be increased, so that the degree of freedom in designing the optical system is improved.

FIG. 39 shows another modification of the light emitting device according to the embodiment of the present disclosure. A light emitting device 210C shown in FIG. 39 has a collimating lens 208 between the excitation light source 180 and the light emitting element 100. With such a configuration, the light emitting element 100 can be irradiated with the collimated excitation light. Therefore, the photoluminescence layer 110 can be uniformly excited.

FIG. 40 illustrates yet another modification of the light emitting device according to the embodiment of the present disclosure. A light emitting device 210D shown in FIG. 40 has a collimating lens 208 between the excitation light source 180 and the light emitting element 100, and further has a condenser lens 206 between the collimating lens 208 and the light emitting element 100. With such a configuration, the excitation light can be converged, so that the light emitting device 100 can be downsized. Therefore, the optical system can be downsized. Moreover, since the distance from the excitation light source 180 to the light emitting element 100 can be increased, the degree of freedom in designing the optical system is improved.

FIG. 41 shows another modification of the light emitting device according to the embodiment of the present disclosure. The light emitting device 210E shown in FIG. 41 has a collimator lens 204 between the light emitting element 100 and the condenser lens 202, similarly to the light emitting device 210B shown in FIG. Further, similarly to the light emitting device 210D shown in FIG. 40, a collimating lens 208 and a condenser lens 206 are provided between the excitation light source 180 and the light emitting element 100. As shown in FIG. 41, the collimator lens 208 and the condenser lens 206 are arranged in this order from the excitation light source 180 toward the light emitting element 100. As illustrated in FIG. 41, the excitation light source 180 and the light emitting element 100 are provided, and between the light emitting element 100 and the optical component (here, the optical fiber 250) that receives light emitted from the light emitting device. , A collimator lens and a condenser lens may be arranged. Thereby, the same effect as that of the light emitting device 210B shown in FIG. 38 and the light emitting device 210D shown in FIG. 40 can be obtained.

As described above, the optical system in the light emitting device of the present disclosure can be designed in various ways. In addition to the configurations illustrated in FIGS. 38 to 41, for example, a configuration in which the collimator lens 208 is omitted from the light emitting device 210D illustrated in FIG. 40 or the light emitting device 210E illustrated in FIG. 41 is also possible. That is, a configuration in which the collimator lens is not arranged between the excitation light source 180 and the light emitting element 100 is also possible. 35 to 41, the condenser lenses (condenser lenses 202 and 206) are shown as a single biconvex lens. However, this is merely for convenience of description, and the condenser lens in the light emitting device of the present disclosure may be a combination of a plurality of lenses. The same applies to the collimating lenses (collimating lenses 204 and 208). Of course, the collimating lenses (collimating lenses 204 and 208) are not limited to biconvex lenses.

As described above, the light emitting device of the present disclosure and the light emitting device including the same have various advantages, and therefore, by applying to various optical devices, advantageous effects can be obtained. For example, the following applications are possible.

The light emitting element of the present disclosure can emit light with high directivity in a specific direction. This high directivity is suitably used, for example, as an edge light type backlight that uses a light guide plate of a liquid crystal display device. For example, when a conventional light source with low directivity is used, the light emitted from the light source is introduced into the light guide plate by the reflecting plate and/or the diffusing material. In the case of a light source having a high directivity in a specific direction, light can be efficiently introduced into the light guide plate even if these optical components are omitted.

Further, for example, if a plurality of light emitting devices 210A shown in FIG. 35 are used and the end surface on the light emitting side of the optical fiber 250 optically coupled to the light emitting device 210A is flatly spread, a set of the light emitting devices 210A is displayed. Can function as. Instead of the light emitting device 210A, any of the light emitting devices 210B to 210E described with reference to FIGS. 38 to 41 may be applied.

Conventional luminaires use optical components including, for example, reflectors to guide isotropically emitted light in a desired direction. On the other hand, according to the embodiment of the present disclosure, since the light emitting element and the optical fiber can be optically coupled with high coupling efficiency, the reflector can be omitted. Alternatively, the complex design for isotropic light can be replaced by a simple design for highly directional light. As a result, the luminaire can be downsized or the design process can be simplified.

The light emitting device of the present disclosure can enhance only light having a specific wavelength. Therefore, a light source that emits only the required wavelength can be easily realized. Further, the wavelength of emitted light can be changed by changing the periodic structure without changing the material of the photoluminescence layer. Further, it is possible to emit light having different wavelengths depending on the angle with respect to the periodic structure. Such wavelength selectivity can be suitably used for, for example, a technique called narrow band imaging (NBI, registered trademark). Further, it can be suitably used for visible light communication.

Further, in the field of lighting, technologies called chromatic color lighting and beautiful color lighting have been developed. These are intended to make the color of the illumination target look beautiful. Chromatic color illumination has the effect of making food such as vegetables look more delicious, while beautiful light illumination has the effect of making the skin look more beautiful. All of these are performed by controlling the spectrum of the light source (that is, the intensity distribution of the wavelength of the emitted light) according to the object. Conventionally, the spectrum of the light used for illumination is controlled by selectively transmitting the light emitted from the light source using an optical filter. That is, since unnecessary light is absorbed by the optical filter, the light utilization efficiency is reduced. On the other hand, the light emitting device of the present disclosure can enhance light of a specific wavelength, and thus does not require an optical filter, and as a result, can improve light utilization efficiency.

The light emitting device of the present disclosure can emit polarized light (linearly polarized light). Conventionally, linearly polarized light has been created by absorbing one of two orthogonal linearly polarized lights that form non-polarized light emitted from a light source using a polarizing filter (also referred to as a “polarizing plate”). Therefore, the light utilization efficiency was 50% or less. When the light emitting device of the present disclosure is used as a polarized light source, it is not necessary to use a polarizing filter, and thus the light utilization efficiency can be improved. Polarized illumination is used, for example, when it is desired to reduce reflected light, such as in a show window or a window glass of a view restaurant. Moreover, it can be used for facilitating the observation of a lesion site by an endoscope, as well as illumination for wash and makeup, which utilizes the fact that the reflection property of the skin surface depends on polarized light.

The polarized light source is suitably used as a backlight of a liquid crystal display device, and also suitably used as a light source of a liquid crystal projector. When used as a light source of a liquid crystal projector, a light source capable of emitting polarized light of three primary colors can be configured by combining with the wavelength selectivity described above. For example, a light emitting element that emits red linearly polarized light, a light emitting element that emits green linearly polarized light, and a light emitting element that emits blue linearly polarized light are connected together to form a disk, and this disk is irradiated with excitation light. However, by rotating the disk, a light source that emits polarized light of the three primary colors of red, green, and blue in time series can be obtained.

The application example of the light emitting element of the present disclosure is not limited to the above, and may be applied to various optical devices. For example, as described below, a light emitting device of the present disclosure can be used to realize a smaller projection device.

[12. Projector]
Hereinafter, an exemplary configuration of a projection device to which the light emitting device of the present disclosure is applied will be described. A projection apparatus according to an exemplary aspect of the present disclosure includes a light source unit, an image forming unit having a light modulation element, and an optical fiber that takes in light from the light source unit from one end and guides the light to the image forming unit. In other words, the light source unit and the image forming unit are connected via the optical fiber. As will be described later in detail, the light modulation element forms an image on a projection target such as a screen or a wall surface by changing the traveling direction of a light beam emitted from an optical fiber according to an image signal.

In an aspect of the present disclosure, a light source unit is disposed in proximity to an excitation light source, a photoluminescence layer that receives excitation light from the excitation light source and emits light having _a wavelength of λ _{a in} air, and the photoluminescence layer. It has a light-transmitting layer and a surface structure formed on the surface of at least one of the photoluminescent layer and the light-transmitting layer and including at least one of a plurality of convex portions and a plurality of concave portions. The above-described configurations can be applied to the photoluminescence layer, the light-transmitting layer, and the surface structure. In other words, it is possible to take out highly directional light from the photoluminescence layer, and it is possible to illuminate a specific direction with light without using optical components such as a reflector and a lens (or with a small size). Therefore, the size of the projection device can be significantly reduced as compared with the conventional one.

The light guided from the light source unit to the image forming unit via the optical fiber may be excitation light from the excitation light source. In another aspect of the present disclosure, the photoluminescent layer, the transparent layer, and the surface structure are disposed inside the image forming unit. In this case, the light modulation element receives the light emitted by the photoluminescence layer and having a wavelength of λ _{a in} the air.

[12-1. Projector having excitation light source in light source section]
42 shows an example of an external appearance of a projection device according to an aspect of the present disclosure. In the configuration illustrated in FIG. 42, the projection device 2300 has a main body unit 2350 and a light projecting unit 2310. The main body unit 2350 is configured to be attachable to, for example, a ceiling inside a room. As shown, the projection device 2300 has an optical fiber 2250 that connects the main body unit 2350 and the light projecting unit 2310. In the projection device 2300, light is generated in the main body unit 2350, and the generated light is sent to the light projecting unit 2310 via the optical fiber 2250.

The light projecting unit 2310 emits light for forming an image (moving image or still image) toward a screen, a wall, or the like. In the configuration illustrated in FIG. 42, the light projecting unit 2310 is provided with an opening 2330, and light for forming an image is emitted to the outside of the light projecting unit 2310 through the opening 2330. .. The light projecting unit 2310 is connected to the main body unit 2350 by a joint such as a hinge, and is configured to be able to change the emission direction of light.

43 shows an example of an optical system in the projection device 2300 shown in FIG. The optical system in the projection device 2300 roughly includes a light source unit 2360A, an image forming unit 2320A, and an optical fiber 2250 that optically couples these. The light source unit 2360A and the image forming unit 2320A are respectively arranged in the main body unit 2350 and the light projecting unit 2310 described above.

In the configuration illustrated in FIG. 43, the light source unit 2360A includes the excitation light source 180 and the disc-shaped light emitting element 100w. The light emitting device 100w is divided into a plurality of regions along the disc-shaped circumferential direction, and each of the plurality of regions has a structure similar to that of the light emitting device 100 or 100a described above. That is, each of the plurality of regions in light emitting element 100w includes a photoluminescent layer and a surface structure. In this example, each of the plurality of regions in the light emitting element 100w has the same structure as the light emitting element described with reference to FIG. 19A, as schematically shown in FIG. Here, an example in which the light emitting element 100a in which the photoluminescence layer 110 is formed on the substrate 140 (here, a transparent substrate) is applied will be described. However, the light emitting element 100 described above may be used instead of the light emitting element 100a. I do not care.

The light emitting element 100w is arranged on the optical path of the excitation light from the excitation light source 180. Examples of the excitation light source 180 are an LED and a laser diode. In this example, the light emitting element 100w is arranged in the main body unit 2350 so that the substrate 140 faces the excitation light source 180, and the excitation light emitted from the excitation light source 180 is emitted from the excitation light source 180 via the substrate 140. It is incident on the photoluminescence layer 110 of 100 w. As described above, the surface structure (here, the periodic structure 120a and/or 120b) in the light emitting device 100w has a function of limiting the directivity angle of the specific light emitted by the photoluminescent layer 110. Therefore, the light of the specific wavelength is strongly emitted from the light emitting element 100w in the specific direction (for example, the front direction).

The light emitting element 100w is rotatably supported in the light projecting unit 2310, and is rotated by a driving device (for example, a motor, not shown in FIG. 43) during operation of the projection device 2300. The excitation light emitted from the excitation light source 180 enters any one of the plurality of regions in the light emitting element 100w according to the rotation angle of the light emitting element 100w.

Typically, the light emitting device 100w has a different periodic structure for each of the plurality of regions. That is, the wavelength of the light strongly emitted from the light emitting element 100w in a specific direction differs for each of the plurality of regions in the light emitting element 100w. Therefore, the light emitting element 100w emits light having different wavelengths depending on which of the plurality of regions the excitation light enters. The light emitting element 100w may be called a directional light emitting color wheel.

One end of the optical fiber 2250 is arranged on the optical path of the light emitted from the light emitting element 100w. By arranging one end of the optical fiber 2250 on the optical path of the light emitted from the light emitting element 100w, the optical fiber 2250 is optically coupled to the light emitting element 100w. As described above, the light emitting device of the present disclosure has a novel structure capable of controlling the directivity of emitted light. Therefore, high coupling efficiency can be realized between the light emitting element 100w and the optical fiber 2250. A condenser lens or the like may be arranged between the optical fiber 2250 and the light emitting element 100w.

The optical fiber 2250 captures the light from the light source unit 2360A in the main body unit 2350 and guides the captured light to the light projecting unit 2310 (see FIG. 42). In this way, the light generated in the light source unit 2360A is sent to the image forming unit 2320A arranged in the light projecting unit 2310 via the optical fiber 2250.

The image forming unit 2320A includes a MEMS (Micro Electro Mechanical System) mirror 2322A that receives light emitted from the optical fiber 2250. The light from the light source unit 2360A taken from one end of the optical fiber 2250 is emitted from the other end of the optical fiber 2250 toward the MEMS mirror 2322A. The light emitted from the optical fiber 2250 spreads according to the numerical aperture of the optical fiber 2250. Therefore, typically, a collimator lens 2260 for obtaining parallel light is arranged between the optical fiber 2250 and the MEMS mirror 2322A. The MEMS mirror 2322A may be arranged at a position where the light emitted from the optical fiber 2250 directly or indirectly enters, and another optical element such as a collimator lens 2260 may be provided between the MEMS mirror 2322A and the optical fiber 2250. Parts may intervene.

The light incident on the MEMS mirror 2322A is reflected at an angle corresponding to the tilt of the movable mirror 2323 in the MEMS mirror 2322A. The light reflected by the movable mirror 2323 is emitted to the outside of the light projecting unit 2310 through the opening 2330 and forms an image.

FIG. 44 shows an outline of an example of the configuration of the projection device 2300 shown in FIG. As described above, the main body unit 2350 has the light source unit 2360A including the excitation light source 180. In this example, the light source unit 2360A arranged in the main body unit 2350 includes the light emitting element 100w. As shown, the main body unit 2350 may further include a driving device 2352 for the light emitting element 100w, a driver 2354 for the excitation light source 180, a control circuit 2356, and an input/output interface 2358.

The input/output interface 2358 has a configuration capable of exchanging electrical signals with an external device (eg, computer, removable memory, etc.), and is wired or wirelessly connected to the external device (eg, a server or terminal device connected to a network). Image data, control signals, etc. The control circuit 2356 includes, for example, a memory and a CPU, and an image processing circuit such as a digital signal processor (DSP), and generates an image signal based on image data (or a signal) input through the input/output interface 2358. To do. Further, the control circuit 2356 controls the operation of each unit in the projection device 2300 based on the input from the input/output interface 2358. The control circuit 2356 controls the turning on and off of the excitation light source 180 by sending a control signal to the driver 2354, for example. A shutter may be provided between the optical fiber 2250 and the excitation light source 180, and the operation of the shutter may be controlled by the driver 2354 to switch the incidence and the interruption of the excitation light on the optical fiber 2250. The shutter may be arranged at any position from the excitation light source 180 to the light modulation element 2322 described later. The control circuit 2356 also controls a driving device 2352 (typically a motor) for rotating the light emitting element 100w, so that excitation light from the excitation light source 180 enters any of a plurality of areas of the light emitting element 100w. Switch to do.

In this example, the light projecting unit 2310 has a driver 2324 for driving the light modulation element 2322 of the image forming unit 2320A. The MEMS mirror 2322A described above is an example of the light modulation element 2322. In the configuration illustrated in FIG. 44, the control circuit 2356 executes control of the driver 2324.

[12-2. Image formation]
Next, a method for forming an image using the MEMS mirror 2322A will be described.

FIG. 45A schematically shows how an image is formed by the light reflected by the MEMS mirror 2322A. The MEMS mirror 2322A includes, for example, a movable mirror supported by a minute beam and a drive mechanism (electrostatic actuator) that changes the tilt of the movable mirror. In the configuration illustrated in FIG. 45A, the MEMS mirror 2322A is a two-dimensional MEMS mirror in which a movable mirror is rotatably supported around two orthogonal axes (here, α axis and β axis). By applying a voltage having an appropriate magnitude as a drive signal to the MEMS mirror 2322A for an appropriate time, the movable mirror can be tilted in a desired direction. By controlling the tilt of the movable mirror, incident light can be reflected toward a desired position on a projection target such as a screen. By making the driving frequencies different about the α axis and the β axis, the light beam reflected by the MEMS mirror 2322A can be scanned in the horizontal direction and the vertical direction.

As described with reference to FIG. 43, the light emitted from the light emitting element 100w and transmitted by the optical fiber 2250 enters the MEMS mirror 2322A directly or indirectly. As described above, the light emitting element 100w includes a plurality of regions in which the wavelengths of light strongly emitted in a specific direction (for example, the normal direction of the light emitting element 100w) are different. For example, a certain region in the light emitting device 100w has a periodic structure that enhances light having a wavelength corresponding to red light, and another region has a periodic structure that enhances light having a wavelength corresponding to green light. Have. Still another region has a periodic structure that enhances light having a wavelength corresponding to blue light. In this way, the peak wavelength of the light emitted in the normal direction of the light emitting device 100w may be different for each region.

Therefore, the wavelength of the light coupled to the optical fiber 2250 can be switched by rotating the light emitting element 100w and switching the region of the light emitting element 100w on which the excitation light enters. That is, the wavelength of light incident on the MEMS mirror 2322A can be switched in a time sequential manner. Therefore, by controlling the rotation of the light emitting element 100w in synchronization with the scanning of the light beam on the projection target, as shown schematically in FIG. 45A, for example, spots of R light, G light, and B light are spotted on the projection target. Can be formed. For example, by scanning the R light beam, the G light beam, and the B light beam, a desired color image can be displayed based on the image signal supplied to the projection device 2300. To express black, for example, the light incident on the MEMS mirror 2322A may be reflected toward the light absorber arranged in the light projecting unit 2310. In addition, you may use the photoluminescent material which has a common periodic structure among several area|regions of the light emitting element 100w, and differs in the light emission wavelength among several area|regions.

The configuration for emitting light of a desired wavelength from the optical fiber 2250 toward the light modulation element 2322 is not limited to the configuration illustrated in FIG. As illustrated in FIG. 45B, a plurality of optical fibers, each of which is optically coupled to a light emitting element that strongly emits light of a different wavelength, and the above-mentioned optical fiber 2250 are connected via an optical fiber coupler 2252. May generate light of a desired wavelength.

In the configuration illustrated in FIG. 45B, the light emitting elements 100r, 100g, and 100b are respectively provided between the excitation light source 180 and the optical fiber 2250r, between the excitation light source 180 and the optical fiber 2250g, and between the excitation light source 180 and the optical fiber 2250b. Are arranged. In the illustrated example, a collimator lens 2270 is arranged between the excitation light source 180 and each of the light emitting elements 100r, 100g and 100b. Each of the light emitting elements 100r, 100g, and 100b has a periodic structure in which the period is set so as to strongly emit light in the red, green, and blue wavelength regions to the front, respectively. Therefore, the light in the red, green, and blue wavelength ranges is incident on one end of each of the optical fibers 2250r, 2250g, and 2250r. The light emitting elements 100r, 100g, and 100b may have photoluminescence layers having different emission wavelengths, and thus may be designed to strongly emit light in different wavelength regions. As illustrated, a condenser lens 2272 may be arranged between the light emitting element 100r and the optical fiber 2250r, between the light emitting element 100g and the optical fiber 2250g, and between the light emitting element 100b and the optical fiber 2250b.

The other ends of the optical fibers 2250r, 2250g, and 2250b are connected via an optical fiber coupler 2252 to the other end of the optical fiber 2250 whose one end is directed to the light modulation element 2322. The optical fiber coupler 2252 has, for example, a structure in which a plurality of optical fibers are coupled by melting, or a structure using a waveguide. The red light transmitted by the optical fiber 2250r, the green light transmitted by the optical fiber 2250g, and the blue light transmitted by the optical fiber 2250b are combined in the optical fiber coupler 2252, and the combined light is emitted from the other end of the optical fiber 2250. Is emitted. At this time, by adjusting the output of each pumping light source 180, light of a desired color (that is, spectrum) can be emitted from the other end of the optical fiber 2250. Thereby, the color of the light beam traveling toward the projection target can be arbitrarily changed. The intensity of the excitation light emitted from each excitation light source 180 can be controlled by the driver 2354r, the driver 2354g, and the driver 2354b connected to the excitation light source 180, respectively. The driver 2354r, the driver 2354g, and the driver 2354b operate under the control of the control circuit 2356 described above, for example.

Alternatively, for example, diaphragms are provided between the light emitting element 100r and the optical fiber 2250r, between the light emitting element 100g and the optical fiber 2250g, and between the light emitting element 100b and the optical fiber 2250b, and by the driver 2354r, the driver 2354g, and the driver 2354b, You may control the opening degree of the diaphragm provided corresponding to each color. By adjusting the degree of aperture opening, the intensity ratio of the combined light can be adjusted, and combined light of any color can be obtained. Here, an example in which the red light, the green light, and the blue light are combined has been described, but the wavelength range of the combined light, the number of light emitting elements to be used, and the like may be set arbitrarily.

[12-3. Modification of Projector]
FIG. 46 shows another example of the optical system in the projection device 2300. 47 shows an outline of an example of a configuration corresponding to the optical system shown in FIG.

In the configuration illustrated in FIGS. 46 and 47, the projection device 2300 includes a light source unit 2360B including the excitation light source 180, an image forming unit 2320B including the MEMS mirror 2322A, and an optical fiber 2250 that optically couples these. In this example, the image forming unit 2320B includes the light emitting element 100w. That is, in this example, as schematically shown in FIG. 47, the light modulation element 2322 and the light emitting element 100w are arranged in the light projecting unit 2310. The driving device 2352 for the light emitting element 100w is also arranged in the light projecting unit 2310. The point that the excitation light source 180 is arranged in the main body unit 2350 is common to the example described with reference to FIGS. 43 and 44.

In the configuration illustrated in FIGS. 46 and 47, one end of the optical fiber 2250 is arranged on the optical path of the excitation light from the excitation light source 180. The optical fiber 2250 takes in the excitation light from the excitation light source 180 and guides the excitation light to the image forming unit 2320B. The light emitting element 100w of the image forming unit 2320B is arranged at a position where the excitation light emitted from the optical fiber 2250 enters. That is, the optical fiber 2250 emits the captured excitation light from the other end toward the light emitting element 100w. A collimator lens or the like may be arranged between the optical fiber 2250 and the light emitting element 100w.

Upon receiving the excitation light, the light emitting element 100w strongly emits light of a specific wavelength in a specific direction (for example, the normal direction of the light emitting element 100w). The MEMS mirror 2322A in the image forming unit 2320B receives the light enhanced by the light emitting element 100w. That is, the MEMS mirror 2322A is arranged at a position where the light emitted from the light emitting element 100w enters. The MEMS mirror 2322A may be arranged at a position where the light enhanced by the light emitting element 100w directly or indirectly enters, and a condenser lens or the like is arranged between the light emitting element 100w and the MEMS mirror 2322A. Good. The MEMS mirror 2322A changes the traveling direction of incident light according to a drive signal.

In this way, the excitation light generated in the light source unit 2360B may be transmitted to the image forming unit 2320B via the optical fiber 2250. With such a configuration, it is possible to display a desired image on the screen or the like.

[12-4. Optical coupling between light emitting element and optical fiber]
FIG. 48 is a schematic diagram for explaining the optical coupling between the light source and the optical fiber. FIG. 48 schematically shows how the light emitted from the light source 2280 is introduced into the optical fiber 2250 via the condenser lens 2290.

As described above, the etendue is preserved in the optical system if there is no diffusion or the like. In the example shown in FIG. 48, the center of the light source 2280, the optical axis of the condenser lens 2290, and the axis L of the optical fiber 2250 are coincident with each other, and the maximum angle formed by the ray diverging from the light source 2280 and the axis L is θ. If the light emitting area of the light source 2280 is S, the etendue Es of the light source 2280 is expressed as Ssin ² θ. The refractive index of air is 1 here.

As described above, when the etendue on the light receiving side, which represents the size of the light receiving ability on the light receiving side, is smaller than the etendue of the light source, it is not possible to take in all the light emitted from the light source, resulting in loss. The dark shaded area in FIG. 48 schematically shows the light introduced into the optical fiber 2250, while the light shaded area schematically shows the light that cannot be introduced into the optical fiber 2250 when the light source 2280 has a large etendue. There is.

The etendue Ef of the optical fiber 2250 on the light receiving side can be represented by using the numerical aperture NA of the optical fiber 2250. The numerical aperture NA of the optical fiber 2250 is expressed by using the maximum angle θf formed by the ray L that can be taken in by the optical fiber 2250 and the axis L, and the size of this angle θf is determined by the condition that total internal reflection occurs inside the optical fiber 2250. That is, when light is introduced into the optical fiber 2250, the size of the etendue on the light receiving side is determined by what kind of optical fiber 2250 is used.

If the size of the etendue on the light receiving side is constant, the amount of light that can be introduced into the optical fiber 2250 does not increase even if the light emitting area of the light source 2280 is increased. This is the same even if the diameter of the condenser lens 2290 arranged between the light source 2280 and the optical fiber 2250 is enlarged.

FIG. 49 schematically shows the relationship between the light emitting area S of the light source 2280 and the amount A of light introduced into the optical fiber 2250. The broken line in FIG. 49 shows the case where the light emission from the light source 2280 is isotropic and the etendue Es of the light source 2280 is relatively large. The coupling efficiency between the light source 2280 and the optical fiber 2250 at this time may be, for example, about 20%. The dashed-dotted line in FIG. 49 shows the case where the light source 2280 has directivity and the etendue Es is relatively small. The solid line in FIG. 49 shows the case where the light source 2280 has perfect directivity and the etendue Es is almost zero. At this time, a coupling efficiency of almost 100% can be achieved. As described above, in the optical coupling between the light source having a certain light emitting area and the optical fiber, it is advantageous that the light source has high directivity.

The surface structure (here, the periodic structure 120a and/or 120b) in the light emitting device 100w is a pseudo conductor that maximizes the intensity of light of a specific wavelength emitted from the photoluminescent layer 110 in a specific direction (for example, the front direction). Wave modes are formed inside the photoluminescent layer 110. The surface structure of the light emitting element 100w limits, for example, the directivity angle of the light of the wavelength λ _a emitted by the photoluminescence layer 110 to less than 15°. Thereby, narrow-angle light distribution is realized. As described above, since the light emitting element 100w has a structure capable of controlling the directivity of the emitted light, high coupling efficiency can be obtained between the light emitting element 100w and the optical fiber 2250. Therefore, the light emitted from the light emitting element 100w can be efficiently transmitted through the optical fiber 2250 (see, for example, FIG. 43). Therefore, even if the optical fiber 2250 is interposed between the light emitting element 100w and the light modulation element 2322 (here, the MEMS mirror 2322A), bright display can be realized. Further, since high coupling efficiency can be obtained between the light emitting element 100w and the optical fiber 2250, it is possible to provide a projection device with reduced power consumption.

According to the light emitting device of the present disclosure, as illustrated in FIG. 42, the main body unit 2350 and the light projecting unit 2310 can be optically coupled with each other by the optical fiber 2250, and thus the optical system for image formation. It is not necessary to house all the optical components in the light projecting unit 2310. Therefore, the light projecting unit can be easily downsized, and the degree of freedom in designing the light projecting unit is also improved.

FIG. 50 shows, as a comparative example, an example of the appearance of a projection device having a light projecting unit in which all the optical components of the image forming optical system are housed. The projection apparatus 2500 shown in FIG. 50 has a configuration in which a light projecting unit 2510 is connected to a main body unit 2550. The light projecting unit 2510 has an opening 2530, and an imaging lens 2332 is arranged in the opening 2530.

FIG. 51 shows a structure for forming an image, which is arranged inside the light projecting unit 2510 of the projection device 2500 shown in FIG. The projection apparatus 2500 is a DLP (Digital Light Processing) type projection apparatus using a digital micromirror device (DMD). As shown in the figure, inside the light projecting unit 2510, a light source 2580 that emits white light, a color wheel 2520, and a digital micromirror device 2322B that receives the light that has passed through the color wheel 2520 (hereinafter referred to as “DMD2322B”). .) and the imaging lens 2332 are housed. The color wheel 2520 has a disc shape and includes a plurality of regions arranged in the circumferential direction. Each of the plurality of regions is a color filter of a different color, and for example, a region that transmits red light (R), a region that transmits green light (G), a region that transmits blue light (B), and It includes a region that allows the white light (W) emitted from the light source 2580 to pass through as it is. The color wheel 2520 is rotatably supported in the light projecting unit 2510, and is rotated by a driving device (not shown) (for example, a motor). By rotating the color wheel 2520, the color of the light incident on the DMD 2322B is switched. The DMD 2322B includes a substrate 2326 and a large number of minute mirrors 2325 arranged on the substrate 2326, and an image is formed by reflecting light incident on each mirror 2325 in a predetermined direction. In FIG. 51, for simplification, for example, two of the mirrors 2325 arranged in a matrix of thousands of rows and thousands of columns are shown. Details of the configuration and operation of the DMD 2322B will be described later.

As illustrated in FIGS. 50 and 51, in the configuration in which the light source 2580 is arranged in the light projecting unit 2510, a member for cooling the light source 2580, such as a relatively large heat sink or fan (not shown in FIG. 51), is provided. It is arranged in the light projecting unit 2510. Therefore, it is difficult to reduce the size of the light projecting unit 2510. In the substantially cylindrical light projecting unit 2510 as shown in FIG. 50, the diameter and the length along the axis thereof can be, for example, about 20 cm and 30 cm, respectively. Further, the weight of the light projecting unit 2510 is increased by using a large heat sink. The weight of the light projecting unit 2510 may be, for example, about 3 kg.

On the other hand, according to the projection device to which the light emitting element of the present disclosure is applied, the light source section and the image forming section can be optically coupled by the optical fiber, and thus the excitation light source 180 and the light modulation element 2322 are connected. It is easy to separate the main body unit 2350 and the light projecting unit 2310. Therefore, it is not necessary to dispose a component that generates a large amount of heat inside the light projecting unit 2310, and it is not necessary to dispose a heat sink or the like inside the light projecting unit 2310. As described above, since the heat sink and the like can be omitted from the inside of the light projecting unit 2310, a smaller and lighter light projecting unit 2310 can be realized. The weight of the light projecting unit 2310 may be, for example, about 0.3 kg. According to the above-described aspect, since it is relatively easy to reduce the size and weight of the floodlight unit 2310, it is possible to use the floodlight unit 2310 for spotlights and downlights in houses, stores, offices, and the like. is there.

Conventionally, laser light may be used as light for displaying an image on a screen. For example, in the optical system shown in FIG. 51, a laser diode (LD) may be used as the light source 2580. On the other hand, in the projection device of the present disclosure, an image is displayed using the light emitted from the light emitting element 100w. According to such a configuration, the light emitted from the light emitting element 100w upon receiving the excitation light is emitted toward the projection target, and thus it is possible to provide a projection device with higher safety. Further, in a configuration using laser light as light for displaying an image, it is necessary to take measures to reduce speckle noise. On the other hand, in the projection device of the present disclosure, since the light for displaying an image is not the laser light, a special mechanism for reducing speckle noise can be omitted.

[12-5. Other Modifications of Projector]
52 and 53 show still another example of the optical system in the projection device 2300. As illustrated in FIGS. 52 and 53, the DMD 2322B described with reference to FIG. 51 may be used as the light modulation element 2322.

In the configuration illustrated in FIG. 52, the projection device 2300 includes the light source unit 2360A described above, the image forming unit 2320C including the DMD 2322B, and the optical fiber 2250 that optically couples these. The light source unit 2360A and the image forming unit 2320C are arranged in the main body unit 2350 and the light projecting unit 2310 (see FIG. 42), respectively.

The light generated by the light source unit 2360A is sent to the image forming unit 2320C via the optical fiber 2250. The DMD 2322B is arranged at a position where the light emitted from the optical fiber 2250 directly or indirectly enters. In this example, a lens system 2340 is placed between the optical fiber 2250 and the DMD 2322B. The lens system 2340 forms an expanded light beam from the light emitted from the optical fiber 2250. The DMD 2322B is uniformly illuminated with the light beam expanded by the lens system 2340.

As described above, the DMD 2322B has a large number of minute mirrors 2325 arranged on the substrate 2326. Each of the mirrors 2325 is supported on the substrate 2326 so that the tilt can be changed by an actuator (not shown). The tilt of each of the mirrors 2325 is changed by about 10° in accordance with a digital input signal from the driver 2324 (see FIG. 44), for example. Each mirror 2325 reflects the incident light toward either the imaging lens 2332 or the light absorber in the light projecting unit 2310, depending on its inclination. As described above, by rotating the light emitting element 100w, it is possible to switch the wavelength of the light incident on the DMD 2322B via the optical fiber 2250. Therefore, it is possible to project a desired color image on the screen by independently changing the inclination of each mirror 2325 in synchronization with the rotation of the light emitting element 100w (for example, about several thousand times per second).

As described above, it is also possible to use a DMD as the light modulation element 2322 and optically couple the light emitting element 100w to the DMD via the optical fiber 2250. According to the embodiment of the present disclosure, high coupling efficiency can be obtained between the light emitting element 100w and the optical fiber 2250, so that an optical system with less optical loss can be realized. Therefore, bright display can be performed. Moreover, since the excitation light source 180 can be arranged in the main body unit 2350, the same effect as the configuration described with reference to FIGS. 43 and 46 can be obtained.

Similar to the configuration described with reference to FIG. 46, the light emitting element 100w may be arranged on the light projecting unit 2310 side. FIG. 53 shows a configuration example in which the light emitting element 100w is arranged on the light projecting unit 2310 side. In the configuration illustrated in FIG. 53, the image forming unit 2320D of the light projecting unit 2310 includes the DMD 2322B and the light emitting element 100w. Even in such a configuration, since the excitation light source 180 is arranged in the main body unit 2350, the same effect as the configuration described with reference to FIGS. 43 and 46 can be obtained.

In addition to the aspects described above, the technology of the present disclosure can be variously modified. For example, LCOS (Liquid Crystal on Silicon) may be used as the light modulation element 2322. The light modulation element 2322 may be an element that reflects or transmits incident light to form an image. In the above-described aspect, the wavelength of the light incident on the light modulation element 2322 is switched by switching which of the plurality of regions in the light emitting element 100w the excitation light enters. However, the present invention is not limited to this example, and light emitting elements may be arranged independently for each wavelength range (for example, red, green, and blue) used for forming a color image.

[13. Light Emitting Device Having Support for Photoluminescence Layer]
Hereinafter, still another modification of the light emitting device of the present disclosure will be described.

FIG. 54A is a cross-sectional view schematically showing an example of a light emitting device including a light emitting element 100' and a support 3540 supporting the light emitting element 100'. 54B is a plan view of the light emitting device as seen from above in FIG. 54A. In these figures, the surface structure 120 in the light emitting device 100 ′ is drawn extremely large, but in reality, the surface structure 120 may have a large number of fine projections or recesses. This point is the same in other drawings of the present disclosure. In the light emitting device shown in FIGS. 54A and 54B, a support 3540 that supports the light emitting element 100' is provided so as to surround the light emitting element 100'.

The support 3540 is in contact with a side portion of the light emitting device 100' to fix the light emitting device 100'. Providing such a support 3540 has the advantages of protecting the periphery of the light emitting element 100' and making it easier to hold. The support 3540 can be composed of, for example, a material having a higher thermal conductivity than the photoluminescent layer 110. Accordingly, the support 3540 can function also as a heat bath or a heat sink that radiates the heat generated in the photoluminescent layer 110 to the outside.

If there is no heat bath for heat dissipation, the photoluminescence layer 110 may have a high temperature at high output and the light emission efficiency may decrease. By bringing the support 3540 having high thermal conductivity into contact with the photoluminescence layer 110, heat dissipation can be promoted and reduction in light emission efficiency can be suppressed. The support 3540 can be made of a material having a relatively high thermal conductivity, such as aluminum, brass, or copper. However, it is not limited to such materials. When the support 3540 is simply provided for the purpose of protecting the light emitting element 100 ′ from impact, the support 3540 may be made of a material having a lower thermal conductivity than that of the photoluminescence layer 110.

The light emitting device 100′ may have the same configuration as any of the light emitting devices of the present disclosure described above. FIG. 54A shows, as an example, a structure of a light emitting element 100′ in which a light transmitting layer 3520 and a photoluminescent layer 110 are formed on a substrate 140. A surface structure (typically a periodic structure) 120 is formed between the translucent layer 3520 and the photoluminescent layer and between the photoluminescent layer 110 and the air layer. Such a configuration is particularly effective when a transparent material such as inexpensive soda glass or borosilicate glass is used as the material of the substrate 140. However, when the above-mentioned inexpensive glass is used, the substrate 140 may be damaged in the step of sintering the photoluminescent material when manufacturing the light emitting device 100′. In order to avoid this, the surface structure 120 is formed on the low-cost substrate 140 with a material having high heat resistance (for example, SiO ₂ , Al ₂ O ₃ , MgO, SiN, Ta ₂ O ₃ , TiO ₂ or the like). It is effective to form the light-transmitting layer 3520 having. Accordingly, when heating from the photoluminescence layer 110 side for a short time with laser light or the like, the heat at the time of sintering is blocked by the light transmitting layer 3520, and damage to the substrate 140 can be prevented. The light emitting device 100′ is not limited to the configuration shown in FIG. 54A, and various modifications can be made as will be described later.

In the illustrated example, the light emitting device further comprises an excitation light source 3510. The excitation light source 3510 irradiates the excitation light obliquely toward the bottom surface of the light emitting element 100' (that is, the interface between the substrate 140 and air). The incident angle of the excitation light is larger than 0°, and preferably, a structure for taking in the light is provided, and is set so as to satisfy the condition that the excitation light is totally reflected in the photoluminescence layer 110. The light capturing structure may be, for example, a triangular prism having a triangular prism shape provided on the surface of the substrate 140 on the excitation light source 3510 side as shown in FIG. 54C. The light-trapping structure 3590 (a triangular prism in this example) may have other structures such as a hemisphere, a pyramid, a diffraction grating, and a blazed diffraction grating. By providing such a structure, reflection on the surface of the substrate 140 can be suppressed and excitation light can be efficiently introduced into the photoluminescence layer 110. Such a structure is described in detail in Japanese Patent Application No. 2015-031515 by the applicant as a light guide structure. For reference, the entire disclosure content of Japanese Patent Application No. 2005-031515 is incorporated herein. The position and orientation of the excitation light source 3510 is adjusted to achieve such an incident angle. As a result, the excitation light enters the photoluminescence layer 110 at an angle inclined with respect to the normal line direction of the photoluminescence layer 110 and propagates in the photoluminescence layer 110. Thereby, the luminous efficiency can be improved as compared with the case where the excitation light is vertically incident on the photoluminescence layer 110.

The surface structure 120 strongly emits light of a specific wavelength in a specific direction. Therefore, it can be said that the surface structure 120 is a structure that also emits the excitation light most strongly in the specific direction. When the emission angle is θ _out , the excitation light source can be arranged so that the excitation light enters the light emitting element 100′ at the same incident angle as θ _out . As a result, the excitation light can be efficiently introduced into the photoluminescence layer 110, and the light emission efficiency can be increased.

In order to allow the excitation light to obliquely enter the light emitting device 100 ′, the support 3540 in the configuration example shown in FIGS. 54A to 54C may have a structure in which the side of the excitation light source 3510 is largely open. When the opened portion is referred to as an opening, the opening has a side surface 3540a inclined with respect to the normal direction of the photoluminescent layer 110. As shown in the drawing, the opening gradually expands from a portion (referred to as a “supporting portion”) 3540b in contact with the light emitting element 100′ toward the excitation light source 3510. In other words, the side surface of the opening has a tapered structure. With such a structure, the excitation light can be obliquely incident on the light emitting device 100' along the side surface 3540a of the opening. The shape of the opening illustrated in FIGS. 54A to 54C is a truncated pyramid having a square bottom surface, but may be any shape as long as it does not interfere with the optical path of the excitation light. For example, instead of tapering the side surface 3540a, a step may be provided.

The light emitting device illustrated in FIGS. 54A to 54C has a surface structure 120 that limits the directivity angle of light of a specific wavelength, as in the other embodiments described above. Therefore, it is possible to improve the directivity of light of a specific wavelength. Further, the light emitting element 100 ′ is fixed to the support 3540 so that a portion (here, the bottom surface of the substrate 140) on which the excitation light is incident is exposed. As a result, the excitation light can be incident at a desired angle while protecting the light emitting device 100'. When the support 3540 is made of a material having a higher thermal conductivity than that of the photoluminescent layer 110, a light emitting device which is excellent in heat dissipation and whose emission efficiency is unlikely to decrease can be realized.

55A and 55B are diagrams showing an example using a light emitting device 100' having a structure different from the above example. This light emitting device 100 ′ has a structure in which the translucent layer 3520 and the surface structure 120 on the surface thereof are removed from the structure shown in FIGS. 54A and 54B. That is, the light emitting device 100 ′ includes the substrate 140, the photoluminescence layer 110 thereon, and the surface structure 120 on the surface thereof. The configuration other than the light emitting element 100' is the same as the configuration shown in FIGS. 54A and 54B. In the example shown in FIGS. 55A and 55B, since the surface structure 120 is provided only on the upper portion of the photoluminescence layer 110, the manufacturing process can be simplified. This configuration is particularly effective when the substrate 140 is made of quartz glass having high heat resistance. Since quartz glass has high heat resistance, it is less likely to be damaged even when the photoluminescent material is sintered. Therefore, the photoluminescent layer 110 can be formed directly on the substrate 140, and the surface structure 120 can be formed.

56A and 56B are diagrams showing an example using a light emitting device 100 ′ having a different structure. This light emitting device 100 ′ has a structure obtained by removing the surface structure 120 on the surface of the photoluminescence layer 110 from the structure shown in FIGS. 54A and 54B. That is, the light emitting device 100 ′ includes the substrate 140, the light transmitting layer 3520 on the substrate 140, the surface structure 120 on the surface thereof, and the photoluminescent layer 110 thereon. The surface structure 120 is provided only at the interface between the photoluminescent layer 110 and the light transmitting layer 3520. Even with such a structure, the manufacturing process can be simplified.

57A and 57B are diagrams showing an example including a support 3540 having a structure different from the example shown in FIGS. 54A and 54B. As shown in FIG. 57B, in the support 3540, the outer peripheral portion and the inner peripheral portion of the side surface 3540a of the support 3540 viewed from the direction perpendicular to the photoluminescent layer are not rectangular but circular. In other words, the shape of the opening is a truncated cone rather than a truncated pyramid. Except for this point, the structure is similar to that of FIGS. 54A and 54B. Even with such a structure, the same effect as the structure shown in FIGS. 54A and 54B can be obtained.

58A and 58B are diagrams showing a configuration example in which the support 3540 in the light emitting device shown in FIGS. 55A and 55B is replaced with the support shown in FIGS. 57A and 57B. Even with such a configuration, since the shape of the side surface of the opening of the support body is different, the same effect as the configuration shown in FIGS. 55A and 55B can be obtained.

59A and 59B are diagrams showing a configuration example in which the support 3540 in the light emitting device shown in FIGS. 56A and 56B is replaced with the support shown in FIGS. 57A and 57B. Even with such a configuration, since the shape of the side surface of the opening of the support body is different, the same effect as the configuration shown in FIGS. 56A and 56B can be obtained.

FIG. 60A and FIG. 60B are diagrams showing an example of a light emitting device in which the support 3540 is provided only on the side surface of the light emitting element 100 ′. In this example, the peripheral portion of the support body 3540 does not project to the excitation light source 3510 side, that is, it does not have an opening that spreads to the excitation light source 3510 side. Except for this point, the configuration is similar to that shown in FIGS. 54A and 54B. In this example, it is possible to realize a directional light emitting device having a simple structure and excellent impact resistance or heat dissipation.

61A and 61B are diagrams showing an example of a light emitting device in which the light emitting element 100' in the configuration shown in FIGS. 60A and 60B is replaced with the light emitting element shown in FIGS. 55A and 55B. Also in this example, a directional light emitting device having a simple structure and excellent heat dissipation can be realized.

62A and 62B are diagrams showing an example of a light emitting device in which the light emitting element 100' in the configuration shown in FIGS. 60A and 60B is replaced with the light emitting element shown in FIGS. 56A and 56B. In this example as well, it is possible to realize a directional light emitting device having a similarly simple structure and excellent heat dissipation.

63A and 63B are diagrams showing an example in which the structure of the support 3540 in the light emitting device shown in FIGS. 54A and 54B is replaced with a different structure. The support 3540 in this example has an opening 3540c extending from the support 3540b in contact with the light emitting element 100' along the optical path of the excitation light. The opening 3540c functions as a light guide path that guides the excitation light to the light emitting element 100'. Excitation light emitted from the excitation light source 3510 propagates along the opening 3540c and obliquely enters the bottom surface of the light emitting device 100'. Even with such a structure, it is possible to realize a directional light emitting device having excellent impact resistance or heat dissipation.

64A and 64B are diagrams showing an example of a light emitting device in which the light emitting element 100' in the configuration shown in FIGS. 63A and 63B is replaced with the light emitting element shown in FIGS. 55A and 55B. 65A and 65B are diagrams showing an example of a light emitting device in which the light emitting element 100' in the configuration shown in FIGS. 63A and 63B is replaced with the light emitting element shown in FIGS. 56A and 56B. In these examples as well, only the structure of the light emitting element 100' is different, and therefore the same effect as that of the configuration shown in FIGS. 63A and 63B can be obtained.

66A and 66B show a configuration example in which a reflection mirror (reflector) 3530 that reflects excitation light is provided in the middle of the light guide path. The structure of the light emitting device 100' may be similar to the structure shown in FIGS. 54A and 54B. In this example, the opening 3540c (that is, the light guide path) of the support 3540 is bent in the middle, and the reflector 3530 is arranged at the bent portion. This reflector 3530 has a reflection characteristic in the wavelength range of excitation light. The reflector 3530 is not limited to a normal mirror, but may be a dichroic mirror. The excitation light reflected by the reflector 3530 enters the bottom surface of the light emitting device 100'. By providing the reflector 3530 in the light guide path, restrictions on the arrangement of the excitation light source 3510 are reduced. As a result, a smaller light emitting device can be realized.

67A and 67B are diagrams showing a configuration example in which the light emitting element 100' in the light emitting device shown in FIGS. 66A and 66B is replaced with the light emitting element shown in FIGS. 55A and 55B. 68A and 68B are diagrams showing a configuration example in which the light emitting element 100' in the light emitting device shown in FIGS. 66A and 66B is replaced with the light emitting element shown in FIGS. 56A and 56B. In these examples as well, only the structure of the light emitting element 100' is different, and therefore, the same effect as the configuration shown in FIGS. 66A and 66B can be obtained.

69A to 71B are diagrams showing a configuration example in which the excitation light is incident from the side surface of the photoluminescence layer 110. 69A and 69B show an example including the light emitting device 100' shown in FIGS. 54A and 54B. 70A and 70B show an example including the light emitting device 100' shown in FIGS. 55A and 55B. 71A and 71B show an example including the light emitting device 100' shown in FIGS. 56A and 56B. In the example illustrated in FIGS. 69A to 71B, the support body 3540 has an opening (that is, a light guide path) 3540c that extends from the side surface (that is, the surface that is not the main surface) of the photoluminescence layer 110 toward the excitation light source 3510. .. Excitation light propagates along the opening 3540c and obliquely enters the side surface of the photoluminescence layer 110. In this way, the excitation light directly enters the photoluminescent layer 110. With such a configuration, a small directional light emitting device can be realized particularly in the vertical direction (that is, the direction perpendicular to the photoluminescence layer).

72A to 75B are diagrams illustrating an example of a light emitting device further including a plurality of heat radiation fins 3560 in addition to the support 3540. 72A and 72B show a configuration in which a radiation fin 3560 is added to the light emitting device shown in FIGS. 55A and 55B. 73A and 73B show a configuration in which a radiation fin 3560 is added to the light emitting device shown in FIGS. 64A and 64B. 74A and 74B show a configuration in which a radiation fin 3560 is added to the light emitting device shown in FIGS. 67A and 67B. 75A and 75B show a configuration in which a radiation fin 3560 is added to the light emitting device shown in FIGS. 70A and 70B. In these examples, the light emitting element shown in FIGS. 55A and 55B is used as the light emitting element 100', but the light emitting element 100' may have another structure already described.

In each of the examples shown in FIGS. 72A to 75B, a plurality of heat radiation fins 3560 are connected to the outer peripheral portion of the support body 3540 around the light emitting element 100 ′ at equal intervals. The support 3540 and the radiation fins 3560 are made of a material having a higher thermal conductivity than that of the photoluminescence layer 110 (eg, aluminum, brass, or copper). The materials of the radiation fins 3560 and the support 3540 may be the same or different. The heat generated in the photoluminescence layer 110 is radiated to the outside by the plurality of heat radiation fins 3560 via the support 3540. As a result, it is possible to realize a directional light emitting device having further excellent heat dissipation. Note that the shape and arrangement of the plurality of heat radiation fins 3560 are not limited to the illustrated example, and may be any structure that allows efficient heat radiation.

In the above example, the support 3540 is a single continuous structure and surrounds the entire periphery of the light emitting element 100 ′, but the support 3540 does not necessarily have such a structure. For example, as shown in FIG. 76A, a part of the support 3540 may be cut around the light emitting element 100 ′, and a part of the photoluminescent layer 110 may be exposed at that part. Further, as shown in FIG. 76B, the support 3540 may be divided into two parts, which are fixed so as to sandwich the light emitting element 100'. As such, the support 3540 need not necessarily be a single united structure. The structure may be such that the light emitting element 100' is fixed such that a part of the light emitting element 100' is opened and the part of the light emitting element 100' on which the excitation light is incident is exposed so as not to obstruct the optical path of the excitation light. For example, the support 3540 may be in contact with only part of the photoluminescent layer 110.

[14. Light source unit with reflector]
FIG. 77 is a diagram showing a schematic configuration of a light source unit (that is, a light emitting device) having a reflector (that is, a reflecting member). The light source unit 4500 shown in FIG. 77 includes an excitation light source 4510, a light emitting element 100a, a reflector 4530, and a collimator lens 4520. The light emitting element 100a has the same structure as the light emitting element 100a shown in FIG. 1C. Instead of the light emitting element 100a, a light emitting element having another structure already described may be used. In FIG. 77, the surface structure 120 of the light emitting device 100a is depicted to be extremely large, but in reality, the surface structure 120 may have a large number of fine protrusions or recesses.

The reflector 4530 is a reflecting member having a reflection characteristic in the wavelength range of excitation light. The reflector 4530 may be, for example, a general mirror made of an alloy of a plurality of metals, or a dichroic mirror formed of a dielectric multilayer film. The reflector 4530 is arranged on the optical path of the excitation light emitted from the excitation light source 4510, reflects the excitation light and guides it to the light emitting element 100a. At this time, the positions and orientations of the excitation light source 4510 and the reflector 4530 are adjusted so that the excitation light propagates while being totally reflected inside the photoluminescent layer 110.

The collimating lens 4520 is arranged between the excitation light source 4510 and the reflector 4530. When the excitation light source 4510 is a light source such as a laser diode, the excitation light is generally emitted as a light flux having a spread. The collimator lens 4520 converts the expanded light flux into parallel light and makes it incident on the reflector 4530. In FIG. 77, collimating lens 4520 is depicted as a single lens, but it may be a combination of a plurality of lenses. Further, the shape thereof can also be appropriately designed according to the required performance.

The light emitting element 100a includes a photoluminescent layer 110 that receives excitation light and emits light having _a wavelength of λ _{a in} air, a substrate 140 (typically a transparent substrate), and a surface formed on the surface of the photoluminescent layer 110. Structure 120 (typically a periodic structure). The surface structure 120 can be a structure similar to any of the surface structures previously described. The surface structure 120 limits the directivity angle of the light of the wavelength λ _a emitted by the photoluminescence layer 110 to, for example, less than 15°. Thereby, narrow-angle light distribution is realized.

In the light source unit 4500 shown in FIG. 77, the excitation light is reflected by the reflector 4530 and then enters the photoluminescence layer 110. That is, the excitation light is incident on the photoluminescence layer 110 such that the optical path of the excitation light is folded. Therefore, the degree of freedom of the positional relationship between the excitation light source 4510 and the light emitting element 100a can be improved. As a result, the light source unit 4500 can be downsized.

FIG. 78 shows an example of a light source unit in which the reflector 4530 is not provided for comparison. In the light source unit 4500c shown in FIG. 78, the excitation light source 4510 is arranged at a position distant from the light emitting element 100a in order to make the excitation light obliquely incident. As a result, the size of the device in the direction parallel to each layer of the light emitting element 100a is increased as compared with the configuration of FIG.

FIG. 79 is a diagram showing another configuration example. In this example, the position and orientation of the excitation light source 4510 and the orientation of the reflector 4530 are different from the example shown in FIG. 77. The excitation light source 4510 in this example emits excitation light in a direction substantially perpendicular to the main surface of the photoluminescence layer 110. The reflector 4530 reflects the excitation light and makes it obliquely incident on the photoluminescence layer 110. Even with such a configuration, the size of the device can be reduced as in the case of FIG. 77.

FIG. 80 is a diagram showing still another configuration example. In this example, the light emitting device includes a member (referred to as a support) 4540 that supports the light emitting element 100a. The support 4540 supports the light emitting element 100a so as to surround the light emitting element 100a. Although the support 4540 appears to be separated into two parts in FIG. 80, it can actually be a single structure connected together. By providing the support 4540, there is an advantage that the periphery of the light emitting element 100a is protected and it is easy to hold.

A part of the support 4540 is a reflector 4530 made of a material that reflects excitation light. The reflector 4530 reflects the excitation light and guides it to the photoluminescent layer 110. As a result, the same function as the configuration shown in FIG. 79 is realized. In this example, since the support 4540 and the reflector 4530 are integrated, impact resistance can be improved. When the support body 4540 is made of a material having high thermal conductivity, the support body 4540 can also function as a heat sink that efficiently releases heat generated by the light emitting element 100a to the outside.

81 shows a modification of FIG. 80. In the light emitting device of this example, the structure of the support 4540 is different from the example shown in FIG. The support 4540 accommodates and holds the excitation light source 4510 and the collimator lens 4520 in addition to the light emitting element 100a. The inclined portion near the portion holding the light emitting element 100a functions as a reflector 4530. In this configuration example, the excitation light source 4510, the collimator lens 4520, the reflector 4530, and the light emitting element 100a are supported in a predetermined arrangement relationship. With such a structure, it is possible to prevent the optical path of the excitation light from shifting due to impact. That is, the impact resistance can be further improved.

FIG. 82 is a diagram showing another modification. The light emitting device in this example includes a light emitting element 100a, a laser module 4580, a safety filter 4560, a lens 4550, a reflector 4530, and a support 4540 supporting these. The laser module 4580 has an excitation light source 4510 including a laser diode and a collimating lens 4520. The excitation light emitted from the excitation light source 4510 is reflected by the reflector 4530 via the collimator lens 4520 and enters the light emitting element 100a at an optimum angle.

When a laser diode is used as the excitation light source 4510, part of the excitation light that has not been converted by the light emitting element 100a passes through the light emitting element 100a. The laser light that has passed through has coherence and may damage the human body, especially the eyes. In order to prevent the laser light from leaking, a safety filter 4560 that cuts light of the wavelength of the excitation light source 4510 is provided. The lens 4550 collects the light that has passed through the safety filter 4560 and introduces it into, for example, an optical fiber.

The reflector 4530 in this example has a rotating shaft 4570 that functions as an angle adjusting mechanism. The reflector 4530 can be manually rotated about the axis of rotation 4570. With such a structure, the incident angle of the excitation light on the light emitting element 100a can be freely adjusted. This adjustment may be done manually, for example, before shipping the product. In addition, as the angle adjusting mechanism, a mechanism in which the angle is automatically adjusted by a combination of a motor and a control circuit for driving the motor may be introduced. Instead of the reflector 4530 having an angle adjusting mechanism, an angle adjusting mechanism may be provided on the pump light source 4510 side. Such an angle adjusting mechanism can be realized by, for example, a mechanism that rotates the excitation light source 4510 around a certain rotation axis.

In the example shown in FIG. 82, the support 4540 holds the lens 4550, the safety filter 4560, the light emitting element 100a, the reflector 4530, and the laser module 4580. Therefore, even if an impact occurs, the relative positional relationship of the respective parts does not shift, and a light emitting device that operates stably can be realized.

As described above, by providing the reflector 4530, it is possible to bend the optical path of the excitation light emitted from the excitation light source 4510 and make the excitation light enter the photoluminescent layer 110. Therefore, the degree of freedom in the positional relationship between the excitation light source 4510 and the light emitting element is improved, and the entire device can be made more compact.

FIG. 83 is a diagram showing another modification of the light emitting device having the support 4540. This light emitting device includes an excitation light source 4510, a collimator lens 4520, a light emitting element 100a, and a support 4540 that supports these. No reflector is provided in this example. Excitation light emitted from the excitation light source 4510 is incident on the photoluminescence layer of the light emitting device 100 a at a desired angle via the collimator lens 4520. Since the excitation light source 4510, the collimator lens 4520, and the light emitting element 100a are integrated via the support 4540, impact resistance is improved.

Subsequently, a specific example of the effect of downsizing by the light source unit having the reflector 4530 will be described.

84A to 84C are diagrams showing an example of the effect obtained by providing the reflector 4530. FIG. 84A shows a configuration example of a light source unit using a conventional light emitting element 700c having no high directivity. FIG. 84B illustrates a configuration example of a light source unit that includes the light emitting element according to the embodiment of the present disclosure and does not include the reflector. FIG. 84C shows a configuration example of a light source unit having a light emitting element and a reflector according to the embodiment of the present disclosure.

In these configuration examples, a laser diode (LD) is used as the excitation light source 4510. Each light source unit can be used as a component of a lighting device. For example, a lighting device suitable for a room of 8 tatami (about 13 m ² ) needs to emit a light flux of about 5000 lm. If the light output of each LD is about 4.3 W and the light flux emitted from each light source unit in the front direction is 500 lumen (lm), it is necessary to integrate about 10 light emitting modules. Therefore, it is required to reduce the size of each light emitting module.

In the light source unit shown in FIG. 84A, a conventional light emitting element 700c having a low directivity is used. Therefore, a large number of excitation light sources 4510 are necessary to emit a light flux of 500 lm in the front direction. Therefore, the size of each light source unit becomes large, and the size of the illumination device in which a large number of light source units are integrated becomes large.

In the light source unit shown in FIG. 84B, the light emitting element 100a having high directivity according to the embodiment of the present disclosure is used. Therefore, for example, one excitation light source 4510 can emit a light flux of 500 lm in the front direction. Since the size of each light source unit can be reduced, the size of the lighting device can be reduced. When the volume of the light source unit shown in FIG. 84A is 100, the volume of the light source unit shown in FIG. 84B can be reduced to 62.5, for example.

In the light source unit shown in FIG. 84C, the reflector 4530 bends the luminous flux of the excitation light to make it enter the light emitting element 100a. Therefore, the size of each light source unit can be further reduced. As a result, the size of the lighting device can be significantly reduced. If the volume of the light source unit shown in FIG. 84A is 100, the volume of the light source unit shown in FIG. 84C can be reduced to 36, for example.

[15. Light emitting device with additional light source]
Aspects described below relate to a light emitting device that obtains light of a desired color (that is, spectrum) by combining lights from a plurality of light sources. The light emitting device according to the aspect described here includes, in addition to the light emitting element according to any of the aspects described above (hereinafter, also referred to as “directional light emitting element” or “directional light source”), another light source ( Hereinafter, it may be referred to as an "additional light source"). The additional light source emits light having a spectrum different from the spectrum of the light emitted by the directional light source. The light emitted from the directional light source and the light emitted from the additional light source are combined inside or outside the directional light source. The combined light can be introduced into, for example, an optical fiber cable (hereinafter, simply referred to as “optical fiber”). Such a light emitting device can be used, for example, for optical fiber illumination.

Here, the “combination” of light means that a plurality of light beams having different spectra intersect with each other to be in a mixed state. It is not always necessary that the propagating directions and divergence angles of the combined light beams are the same. The first light emitted from the directional light source and the second light emitted from the additional light source are combined inside or outside the directional light source. In an aspect where the second light passes through the directional light source, the first and second light may be combined inside the directional light source. The first light and the second light may be combined outside the directional light source by an optical system, a light guide, or the like.

The spectrum of light emitted from the directional light source may lack some wavelength components as compared with the spectrum of light required in an actual usage scene. By using the additional light source, the deficient wavelength component can be compensated. Furthermore, the color and brightness of the illumination light can also be adjusted by adjusting the spectrum and intensity of the light emitted by each light source.

FIG. 85 is a diagram schematically showing an example of such a light emitting device. This light emitting device includes a light emitting element 100 ′, an excitation light source 180, an additional light source 5500, an optical system 5520, and an optical fiber 5530. The optical system 5520 includes a collimator lens 5520a and a condenser lens 5520b. In the illustrated example, the light emitting device 100' has the same structure as the light emitting device 100a shown in FIG. 1C, but may have another structure such as that of FIG. 1A.

The additional light source 5500 can be, for example, a light source using a laser diode or other directional light emitting device. The additional light source 5500 emits light having a spectrum different from the spectrum of the light emitted from the light emitting element 100'. The light emitted by the additional light source 5500 is light having a spectral component that is insufficient in the light emitted from the light emitting element 100'. For example, when the white light is the desired light and the light emitting device 100′ emits light in the yellow (red and green) wavelength range, the additional light source 5500 emits light in the blue wavelength range. Can be configured to. The light from the additional light source 5500 is hardly absorbed or scattered except when it is incident at a specific angle that resonantly couples to the guided modes in the photoluminescent layer. Therefore, as shown in FIG. 85, when the light from the additional light source 5500 is incident perpendicularly to the photoluminescence layer of the light emitting device 100', most of the light passes through the light emitting device 100'.

The excitation light source 180 is provided separately from the additional light source 5500, and excites the photoluminescent material in the light emitting device 100' to emit light. The excitation light source 180 causes excitation light to enter from a direction inclined with respect to the normal direction of the photoluminescence layer of the light emitting device 100', for example.

The first light generated by the excitation light incident on the light emitting element 100' and the second light emitted from the additional light source 5500 and incident on the light emitting element 100' are combined inside the light emitting element 100'. More specifically, the second light is focused on a point in the photoluminescent layer in the light emitting device 100', and is combined at the moment when the first light is generated. The combined first and second lights propagate outside the light emitting device 100' in a mixed state. This combined light is converted into parallel light by a collimator lens 5520a and focused by a condenser lens 5520b. The focused light is incident on the optical fiber 5530. In this way, the optical system 5520 including the lenses 5520a and 5520b combines (or combines) the first light and the second light and introduces the combined light into the optical fiber 5530. The optical fiber 5530 emits the introduced light from the tip. Thereby, light of a desired color can be emitted to a position away from the light source unit including the light emitting element 100' and the additional light source 5500. The optical fiber 5530 shown in FIG. 85 is drawn as an element having a relatively short shape, but a long optical fiber 5530 such as several meters to several hundred meters can be used depending on the application.

FIG. 86 is a diagram showing a more detailed configuration example of the light emitting device. The light emitting device 5400 is a connector for connecting the optical fiber 5530 with a control circuit 5570 for controlling the excitation light source 180 and the additional light source 5500, in addition to the above-described light emitting element 100′, the additional light source 5500, the excitation light source 180, and the optical system 5520. And 5580. In this example, the optical fiber 5530 is an element external to the light emitting device 5400.

The control circuit 5570 may be an integrated circuit including a processor, such as a microcontroller connected to the pump light source 180 and the additional light source 5500. The control circuit 5570 instructs the excitation light source 180 and the additional light source 5500 to change the intensity of the emitted light, for example, according to the input from the user. As a result, the intensity ratio between the first light emitted from the light emitting element 100' and the second light emitted from the additional light source 5500 is adjusted. As a result, the intensity and color of the combined light can be changed. In addition to such control, the intensity ratio of the first light and the second light is adjusted by changing the size of the diaphragm 5540 arranged between the optical system 5520 and the light emitting element 100′, for example. May be.

The excitation light source 180 is, for example, a laser light source and causes excitation light to be incident on the light emitting element 100' at an angle at which total reflection occurs in the photoluminescent layer of the light emitting element 100'. Thereby, light emission can be efficiently generated in the light emitting element 100'.

The connector 5580 is a terminal for connecting the optical fiber 5530, and is provided in the housing of the light emitting device 5400. The optical fiber 5530 can be inserted into and removed from the connector 5580. Accordingly, for example, in the case where the optical fiber 5530 is a long cable laid in a building, even when the light emitting device 5400 fails, or when it is desired to replace the light emitting device 5400 with a different light emitting characteristic, the light emitting device 5400 can be easily replaced. ..

As described above, the light emitting device illustrated in FIGS. 85 and 86 includes the first light source that is a directional light source and the second light source that is an additional light source. The first light source includes a photoluminescence layer that emits first light including light having _a wavelength of λ _a in air, _a light-transmissive layer disposed in proximity to the photoluminescence layer, and a photoluminescence layer and a light-transmissive layer. And a surface structure formed on at least one surface. The surface structure includes at least one of a plurality of convex portions and a plurality of concave portions, and limits the directivity angle of light having _a wavelength λ _{a in} the air emitted by the photoluminescent layer. For example, let D _int-a be the distance between the centers of two adjacent convex portions or the centers of two adjacent concave portions in the surface structure, and let n be the refractive index of the photoluminescent layer for light having _a wavelength λ _{a in} air. _{Assuming wav-a} , the relationship of λ _a /n _wav-a <D _int-a <λ _a holds. Alternatively, assuming that the surface structure has at least one periodic structure, the refractive index of the photoluminescent layer for light having a wavelength λ _{a in} air is n _wav-a, and the period of at least one periodic structure is p _a , Λ _a /n _wav-a <p _a <λ _a . As a result, the light emitted from the first light source and having the wavelength λ _{a in} the air has the maximum intensity in the first direction that is predetermined by at least one of the plurality of convex portions and the plurality of concave portions. On the other hand, the second light source emits second light including light having _a wavelength of λ _b (≠λ _a ) in the air. The first light emitted from the first light source and the second light emitted from the second light source are combined. The combined light is taken into one end of the optical fiber and emitted from the other end, for example.

With such a configuration, it is possible to supplement the spectrum that is insufficient with the first light source, which is a directional light source, with the second light source, and obtain light with a desired spectrum. It is also possible to adjust the spectrum of the light finally obtained by adjusting the intensity ratio of the first light source and the second light source. As a result, it is possible to realize an optical fiber illumination whose color and brightness can be adjusted. Instead of the optical fiber, a light diffusing plate may be arranged at a position where the first and second lights are combined. The light diffused by the light diffusion plate can be used as illumination. Similarly, in other examples described later, a light diffusing plate may be arranged instead of the optical fiber 5530.

FIG. 87 is a diagram showing an example of a configuration in which the additional light source 5500 also functions as excitation light. In this example, the second light emitted by the additional light source 5500 includes a component of light that functions as excitation light. A part of the second light passes through the light emitting element 100' and is combined by the optical system 5520 with the first light emitted from the light emitting element 100'. The additional light source 5500 is arranged so that the excitation light enters the light emitting element 100 ′ at a specific incident angle θ.

When the photoluminescent material is resonantly excited, it can be efficiently excited by entering the excitation light at a specific oblique angle θ. Generally, the wavelength of the excitation light is shorter than the wavelength of the light of the narrow-angle light distribution from the light emitting element 100′, and therefore the light of the narrow-angle light distribution is emitted at an angle smaller than the angle θ. Therefore, in this aspect, a lens 5520a having a numerical aperture (NA _lens ) of sin θ or more is used in order to take in light from the front (angle 0°) to angle θ. By using such a lens 5520a, both the light with the narrow-angle light distribution and the excitation light can be taken into the optical system 5520.

Further, when the configuration of the lens 5520b is the same as that of the lens 5520a, by selecting an optical fiber 5530 having a numerical aperture (NA _fiber ) equal to or greater than sin θ, most of the light captured by the optical system 5520 (ideal All can be introduced into the optical fiber 5530. When the lens 5520b has a different configuration from the lens 5520a, the optical fiber 5530 that satisfies NA _fiber >sin θ′ is defined by setting the incident angle of the light beam condensed by the lens 5520b on the optical fiber 5530 to θ′ (≠θ). You can use it.

In the example shown in FIG. 87, since the additional light source 5500 also functions as an excitation light source, the number of light sources can be reduced. Therefore, the cost and the size of the device can be reduced.

FIG. 88 is a diagram showing still another configuration example of the light emitting device. In this light emitting device, the configuration of the optical system 5520 and the position of the additional light source 5500 are different from those in the above example. The optical system 5520 in this example has a dichroic mirror 5520c arranged between the lens 5520a and the lens 5520b. The additional light source 5500 is arranged on the front side (right side of the drawing) of the light emitting element 100', not on the back side (left side of the drawing). The additional light source 5500 is arranged so that the second light is incident on the dichroic mirror 5520c. In addition, in FIG. 88, the illustration of the excitation light source that makes the excitation light incident on the light emitting element 100 ′ is omitted. Similarly, in the following drawings, the illustration of the excitation light source may be omitted.

The dichroic mirror 5520c has a high transmittance in the wavelength range of the first light emitted from the light emitting device 100′ and a high reflectance in the wavelength range of the second light emitted from the additional light source 5500. Is designed. The additional light source 5500 is arranged so that the second light intersects the first light from the light emitting element 100' (orthogonal in the example of FIG. 88). A dichroic mirror 5520c is arranged at a position where the first light and the second light intersect. The angle of the dichroic mirror 5520c is adjusted so that the transmitted light of the first light and the reflected light of the second light propagate in the same direction. The first and second lights are combined by the dichroic mirror 5520c, condensed by the lens 5520b, and introduced into the optical fiber 5530. With such a configuration, light having a desired spectrum can be obtained as in the other examples described above.

FIG. 89 is a diagram showing still another configuration example of the light emitting device. This light emitting device is different from the above-described example in that the first light and the second light are combined by the optical fiber 5530 instead of the optical system 5520. The light emitting device in this example includes an optical fiber 5530 that is branched in two directions on the way. Hereinafter, one branched portion 5530a will be referred to as a first optical fiber, and the other branched portion 5530b will be referred to as a second optical fiber. The first optical fiber 5530a and the second optical fiber 5530b are connected at a connection point 5530c. The first light from the light emitting element 100' is incident on the first optical fiber 5530a via the optical system 5520. On the other hand, the second light from the additional light source 5500 enters the second optical fiber 5530b. These lights are combined at the connection point 5530c of the optical fiber.

With such a configuration, desired light can be emitted from the optical fiber 5530. A device for branching/coupling light may be provided at a position corresponding to the connection point 5530c of the optical fiber 5530 shown in FIG. In that case, a similar configuration can be realized by connecting a plurality of optical fibers to the device.

FIG. 90 is a diagram showing still another modification of the light emitting device. In this example, the additional light source 5500 is composed of a directional light emitting element similar to the light emitting element 100′. The additional light source 5500 has a photoluminescence layer, a translucent layer, and a surface structure, like the light emitting element 100′. Whereas the surface structure of the light emitting device 100′ limits the directivity angle of light of wavelength λ _a , the additional light source 5500 limits the directivity angle of light of wavelength λ _b (≠λ _a ). The light emitting device 100′ and the additional light source 5500 may be a single laminated structure. Also in this example, the first light from the light emitting element 100 ′ and the second light from the additional light source 5500 are combined by the optical system 5520 and introduced into the optical fiber 5530.

FIG. 91 is a diagram showing a part of a light emitting device realized by tiling a plurality of directional light emitting elements. This light emitting device includes a plurality of light emitting elements (first light sources) 100r that emit light in a red wavelength range, a plurality of light emitting elements (second light sources) 100g that emit light in a green wavelength range, and a blue wavelength range. It has a structure in which a plurality of light emitting elements (third light sources) 100b that emit light in the region are arranged one-dimensionally or two-dimensionally. Although five light emitting elements are shown in FIG. 91, a larger number of light emitting elements may be arranged in practice. The light emitted from these light emitting elements 100r, 100g, 100b is condensed by the lens 5520d and introduced into the optical fiber 5530. Accordingly, white light can be emitted from the optical fiber 5530. In this example, light sources of three colors of red, green, and blue are used, but the colors (that is, spectra) of the light emitted from each of the first light source, the second light source, and the third light source are set arbitrarily. You may By combining three types of directional light sources as in this example, the color of emitted light can be adjusted more flexibly. Although three types of light sources are used in this example, four or more types of light sources may be combined. The second light source and the third light source are not limited to the directional light emitting element, and may be other light sources such as a laser light source.

FIG. 92 is a diagram showing still another example of the light emitting device. The light emitting device in this example has an additional light source 5500 that also functions as an excitation light source, and the optical fiber 5530 combines the first light and the second light. As shown in the figure, the first light from the light emitting device 100' is condensed by the lens 5520a and the lens 5520e and introduced into the first optical fiber 5530a which is one of the two branched parts of the optical fiber 5530. On the other hand, the second light from the additional light source 5500 passes through the light emitting element 100′, is condensed by the lens 5520a and the lens 5520f, and is introduced into the second optical fiber 5530b which is the other of the two branched parts of the optical fiber 5530. It As a result, the first light and the second light are combined at the connection point 5530c and emitted from the optical fiber 5530.

FIG. 93 is a diagram showing still another example of the light emitting device. This example is similar to the configuration shown in FIG. 87, but the number of lenses is different. Another lens 5520g is arranged between the lens 5520a and the light emitting element 100'. Since the lens 5520g is arranged at a position close to the light emitting element 100', the second light transmitted through the light emitting element 100' can be taken in even if the incident angle of the second light from the additional light source 5500 is large. The lens 5520a makes up for the lack of bending of the optical path of the second light bent by the lens 5520g. As a result, the optical axis of the first light from the light emitting element 100' and the optical axis of the second light from the additional light source 5500 are adjusted to be substantially parallel. These lights are condensed by the lens 5520b and introduced into the optical fiber 5530. Three lenses are used in this example, but the number of lenses is arbitrary. Further, the shape, size, and position of each lens are not limited to the illustrated example, and may be appropriately designed. For example, as shown in FIG. 94, the number of lenses in the optical system may be one (lens 5520a in the illustrated example). In this example, since the number of lenses is small, the light emitting device can be constructed at low cost.

FIG. 95 is a diagram showing still another configuration example of the light emitting device. The light emitting device in this example includes a light emitting element 100′, a lens 5520a arranged on one side of the light emitting element 100′, a mirror (reflector) 5560 arranged on the other side, and an optical fiber 5530 branched into two. And an additional light source 5500. The additional light source 5500 introduces excitation light into one of the branched parts of the optical fiber 5530. The excitation light passes through the lens 5520a and enters the light emitting device 100'. Part of the excitation light that has entered the light emitting device 100' is absorbed by the photoluminescent layer and converted into the first light. Another part of the excitation light passes through the light emitting element 100', is reflected by the mirror 5560, and passes through the light emitting element 100' again. The first light emitted from the light emitting element 100' and the excitation light (second light) that has passed through the light emitting element 100' are condensed by the lens 5520a and introduced into the optical fiber 5530. As a result, the first light and the second light are combined and emitted from the optical fiber 5530. Thus, the mirror 5560 may be used to utilize the reflected excitation light.

As described above, the light emitting device having the additional light source can be variously modified. In any of the modified examples, the first light emitted from the first light source, which is a directional light source, and the second light emitted from the second light source are combined to obtain light having a desired spectrum. it can.

FIG. 96 is a diagram showing an application example to a home fiber lighting system. This fiber lighting system includes a light emitting device (also referred to as a light source unit) 5400 and a plurality of optical fibers 5530. The light source unit 5400 is installed at a predetermined place in the house, and a plurality of optical fibers 5530 are laid from the light source unit 5400 to the lighting installation position in each room. In addition, in FIG. 96, the portion depicted as one optical fiber may actually be a bundle of a plurality of optical fibers. The configuration of light source unit 5400 is not limited to the configuration described with reference to FIG. 86. A light source unit 5400 shown in FIG. 96 has a configuration similar to that of the light emitting device of any of FIGS. 85 to 96 described above, and combines light from a plurality of light sources including at least one directional light source to form a plurality of light sources. It is introduced into the optical fiber 5530. As a result, desired light is sent to each illumination mounting position and can be used as illumination light. The color and brightness of the illumination light can be changed by changing the outputs of the plurality of light sources depending on the situation. Such a fiber lighting system can be used not only in the home but also in various facilities such as an office building, an underground mall, and a stadium.

The function of easily adjusting the spectrum can be applied to, for example, the above-mentioned technologies called beautiful color illumination and chromatic color illumination. These are techniques for making an illuminated object look beautiful by controlling the spectrum of the light source (that is, the intensity distribution of the wavelength of emitted light). For example, it is possible to make the skin look more beautiful by reducing the light having a wavelength of about 570 nm to 580 nm that causes the dullness of the skin to be noticeable. By using the light emitting device of the present disclosure and synthesizing light in the blue to green wavelength range of 570 nm or less and light in the red wavelength range of 580 nm or more, such beautiful light color illumination can be realized. Is.

Further, for example, by suppressing the component of wavelength around 580 nm and strengthening the red component on the long wavelength side, the red color of food can be made to appear more vivid. As a result, for example, red meat and fish, and red fruits and vegetables can be made more vivid. By using the light-emitting device of the present disclosure and synthesizing light in the blue to green wavelength range of 570 nm or less and light in the red wavelength range of 590 nm or more, such chromatic color illumination can be realized. It is possible. Similar wavelength control can also be used to make the scenery of red flowers and autumn leaves look more vivid.

The light emitting device according to the above-described mode in which the spectrum of the emitted light can be adjusted can also be used for the purpose of determining the freshness of food. For many foods, the spectrum of reflected light changes as the freshness decreases. For example, in the case of beef, the components in the wavelength range of about 600 nm to 700 nm decrease as the freshness decreases. Therefore, the freshness of the food can be easily determined by irradiating the food with only light in the wavelength range in which the reflectance greatly changes according to the freshness and observing the intensity of the reflected light. Depending on the food, the reflectance may change greatly in a plurality of different wavelength ranges. Even in such a case, by using a light emitting device that combines lights of different spectra from a plurality of light sources, it is possible to easily obtain light of a plurality of desired wavelength bands.

[16. Light emitting device that combines lights emitted in mutually different directions]
The aspect described below relates to a light emitting device that combines and uses lights of different wavelength ranges emitted from one light emitting element. As described above, the light emitting device of the present disclosure strongly emits light of a specific wavelength in a specific direction and strongly emits light of another wavelength in another direction. By utilizing this characteristic, a plurality of light beams emitted in different directions and having different wavelength ranges can be combined and utilized by using an optical system or a light guide. By synthesizing light in a plurality of wavelength ranges, it is possible to supplement the spectrum component lacking in one light flux with the other light flux, and bring it closer to light having a desired spectrum. The combined light can be introduced into an optical fiber, for example. Such a light emitting device can also be used, for example, for optical fiber illumination.

FIG. 97 is a diagram schematically showing an example of a light emitting device that combines lights in a plurality of wavelength bands emitted in different directions from a light emitting element. This light emitting device includes a light emitting element 100 ′, an optical system 6520, and an optical fiber 6530. The optical system 6520 includes a collimator lens 6520a and a condenser lens 6520b. In FIG. 97, as the light emitting element 100', a structure similar to that of the light emitting element 100 shown in FIG. 1A is illustrated, but a light emitting element having another structure described with reference to FIG. 1C or the like may be used. It should be noted that FIG. 97 simply illustrates each of the constituent elements, and does not necessarily match the actual structure. The same applies to the other figures. Although omitted in FIG. 97, an excitation light source that makes excitation light incident on the light emitting element 100 ′ may be provided in practice.

Here, a material having a broad emission spectrum is used as the photoluminescent material in the photoluminescent layer. Light of a certain wavelength λ _a emitted from the photoluminescent material has directivity in the direction of a specific emission angle, and light of another wavelength λ _b has a directivity in the direction of another emission angle. The optical system 6520 synthesizes (or combines) the light flux containing the first light of the wavelength λ _a and the light flux containing the second light of the wavelength λ _b , and introduces them into the optical fiber 6530. The optical fiber 6530 emits the introduced light from the tip portion. Accordingly, it is possible to realize optical fiber illumination that emits light having a desired spectrum to a position away from the light source unit including the light emitting element 100′. The optical fiber 6530 shown in FIG. 97 is drawn as an element having a relatively short shape, but a long optical fiber 6530 such as several meters to several hundred meters can be used depending on the application.

FIG. 98 is a diagram showing details of a configuration example of the light emitting device. The light emitting device 6400 includes an excitation light source 180, a control circuit 6570 for controlling the excitation light source 180, and a connector 6580 for connecting an optical fiber 6530, in addition to the above-described light emitting element 100 ′ and the optical system 6520. In this example, the optical fiber 6530 is an element external to the light emitting device 6400.

The control circuit 6570 may be an integrated circuit including a processor, such as a microcontroller connected to the excitation light source 180, for example. The control circuit 6570 instructs the excitation light source 180 to change the intensity of the emitted light, for example, according to the input from the user. This makes it possible to change the intensities of the first light and the second light emitted from the light emitting element 100'. In addition to such control, the intensity ratio of the first light and the second light is changed by changing the size of the diaphragm 6540 arranged between the optical system 6520 and the light emitting element 100′. Can also This makes it possible to adjust the spectrum of the combined light.

The excitation light source 180 is, for example, a laser light source and causes excitation light to be incident on the light emitting element 100' at an angle at which total reflection occurs in the photoluminescent layer of the light emitting element 100'. Thereby, light emission can be efficiently generated in the light emitting element 100'.

The connector 6580 is a terminal for connecting the optical fiber 6530, and is provided in the housing of the light emitting device 6400. The optical fiber 6530 can be inserted into and removed from the connector 6580. Accordingly, for example, in the case where the optical fiber 6530 is a long cable laid in a building, even when the light emitting device 6400 fails, or when it is desired to replace the light emitting device 6400 with a different light emitting characteristic, the light emitting device 6400 can be easily replaced. ..

As described above, the light emitting device illustrated in FIGS. 97 and 98 emits light including the first light having the wavelength λ _a in the air and the second light having the wavelength λ _b in the air. A layer, a light-transmissive layer disposed in the vicinity of the photoluminescent layer, a surface structure formed on at least one surface of the photoluminescent layer and the light-transmissive layer, and first light and second light. And an optical system for The surface structure has a plurality of convex portions and a plurality of concave portions, and limits the directivity angle of the first light. For example, let D _int be the distance between the centers of two adjacent convex portions or the centers of two adjacent concave portions in the surface structure, and let the refractive index of the photoluminescent layer for the first light with _a wavelength λ _{a in} air be If n _wav-a , the relationship of λ _a /n _wav-a <D _int-a <λ _a is established. Alternatively, assuming that the surface structure has at least one periodic structure, the refractive index of the photoluminescent layer for light having a wavelength λ _{a in} air is n _wav-a, and the period of at least one periodic structure is p _a , Λ _a /n _wav-a <p _a <λ _a . As a result, the intensity of the first light becomes maximum in the first direction predetermined by at least one of the plurality of convex portions and the plurality of concave portions, and the second light is different from the direction of the first light. The intensity is maximum in the second direction. The optical system combines the light flux including the first light emitted in the first direction and the light flux including the second light emitted in the second direction. The combined light is taken into one end of the optical fiber and emitted from the other end, for example.

With such a configuration, it is possible to supplement the spectrum component, which is insufficient with the first light emitted in one direction, with the second light. As described above, the intensity ratio of the first light and the second light can be adjusted by control such as adjusting the size of the diaphragm 6540. As a result, it is possible to realize an optical fiber illumination whose color and brightness can be adjusted. According to the aspect described here, there is also an advantage that the device can be downsized as compared with the case of combining lights from a plurality of light sources. By combining light of two or more kinds of wavelengths or colors emitted from one light emitting element, it is possible to realize a small light emitting device capable of controlling the spectrum. Instead of the optical fiber, a light diffusing plate may be arranged at a position where the first and second lights are combined. The light diffused by the light diffusion plate can be used as illumination. Similarly, in other examples described later, a light diffusion plate may be arranged instead of the optical fiber 6530.

FIG. 99 is a diagram showing an example of a light emitting device that obtains white light by combining lights of three specific wavelengths. In this example, the light emitting element 100' emits light in three wavelength bands of red (R), green (G), and blue (B) in different directions. The optical system 6520 synthesizes these three colors of light and introduces them into the optical fiber 6530. Accordingly, white light can be emitted from the optical fiber 6530. In this example, red, green, and blue lights are used to obtain white light, but the color combination may be set arbitrarily.

FIG. 100 shows an example in which the first light emitted from the light emitting element 100′ in the first direction and the second light emitted in the second direction are introduced into different optical fibers 6530a and 6530b. ing. The light emitting device in this example has a first optical system including lenses 6520a and 6520b and a second optical system including lenses 6520c and 6520d. The first optical system is arranged to introduce the first light into the first optical fiber 6530a and the second optical system is arranged to introduce the second light into the second optical fiber 6530b. The first optical fiber 6530a and the second optical fiber 6530b are connected to one optical fiber 6530d by the combiner 6640. The first light and the second light are combined by a combiner 6640 which is a connection point of the two optical fibers 6530a and 6530b. With such a configuration, the same effect as the above example can be obtained.

FIG. 101 is a diagram showing another example of a light emitting device in which a plurality of optical fibers are connected. This light emitting device includes a light emitting element 100', a lens 6520a, a lens array 6610, a plurality of light modulators 6582, a plurality of optical fibers 6530, and a combiner 6640. In this light emitting device, red (R), green (G), and blue (B) lights emitted from the light emitting element 100′ in different directions are collimated by a lens 6520a and are condensed by a lens array 6610. The light is introduced into the plurality of optical fibers 6530 through the optical modulator 6582. Each light modulator 6582 receives any one of red, green, and blue light depending on its position and outputs it to the corresponding optical fiber 6530. The light modulator 6582 can reduce or block unnecessary light to the optical fiber 6530. The lights propagating through the plurality of optical fibers 6530 are combined by the combiner 6640 and emitted from one optical fiber.

With such a configuration, light having an arbitrary spectrum can be generated. In this example, since the lights of the three primary colors of red, green, and blue can be output individually, the light can be used not only for illumination but also for display devices such as a display and a projector.

102 is a diagram showing an example in which a plurality of light emitting elements 100r, 100g, 100b are tiled instead of the light emitting element 100' in the configuration of FIG. The light emitting elements 100r, 100g, and 100b are directional light emitting elements that respectively emit light in the red, green, and blue wavelength ranges at a narrow angle. The plurality of light emitting elements 100r, 100g, 100b are arranged one-dimensionally or two-dimensionally. Although five light emitting elements are shown in FIG. 102, a larger number of light emitting elements may be arranged in practice. The light emitted from these light emitting elements 100r, 100g, 100b is condensed by the lens 6520a and introduced into the plurality of optical fibers 6530 through the lens array 6610 and the plurality of optical modulators 6582. With such a configuration, the same effect as that of the configuration of FIG. 101 can be obtained.

In the examples of FIGS. 101 and 102, the lights of red, green, and blue are combined, but the combination is not limited to this combination, and a combination of other colors may be used. Further, the number of types of colors to be combined is not limited to three, and may be two or four or more.

FIG. 103 is a diagram showing an example in which a part of the light emitted from the excitation light source 180 is further used in the configuration shown in FIG. In this example, the excitation light source 180 causes the light emitting element 100 ′ to inject a third light (for example, blue light) including the excitation light from a direction inclined (at an incident angle θ) with respect to the normal direction of the photoluminescent layer. It is arranged to let. Part of the third light is used for light emission, and the other part is transmitted through the light emitting element 100'. The optical system 6520 introduces, into the optical fiber 6530, the third light transmitted through the light emitting element 100 ′ in addition to the first light and the second light emitted from the light emitting element 100 ′. With such a configuration, when a desired spectrum cannot be generated only by the light emitted from the light emitting element 100 ′, the insufficient spectrum component can be supplemented.

As described above, when the photoluminescent material is resonantly excited, it can be efficiently excited by entering the excitation light at a specific oblique angle θ. Further, generally, the wavelength of the excitation light is shorter than the wavelength of the light of the narrow-angle light distribution from the light emitting element 100′, and the light of the narrow-angle light distribution is emitted at an angle smaller than the angle θ. As described with reference to FIG. 87, by using a lens 6520a having a numerical aperture (NA _lens ) of sin θ or more, light from the front (angle 0°) to angle θ is taken in, and narrow-angle light distribution is performed. Both the light and the excitation light can be taken into the optical system 6520.

When the configuration of the lens 6520b is the same as that of the lens 6520a, most of the light captured by the optical system 6520 (ideally, by selecting the optical fiber 6530 having a numerical aperture (NA _fiber ) of sin θ or more). All) can be introduced into the optical fiber 6530. In the case where the lens 6520b has a configuration different from that of the lens 6520a, if the incident angle of the light beam condensed by the lens 6520b to the optical fiber 6530 is θ′ (≠θ) and the optical fiber 6530 that satisfies NA _fiber >sin θ′ is used, Good.

FIG. 104 is a diagram showing an example in which the position of the excitation light source 180 in FIG. 103 is changed. In this example, the excitation light source 180 is arranged perpendicularly to the light emitting element 100 ′ so that the third light including the excitation light is incident. In such a configuration, most of the third light is transmitted through the light emitting element 100', so that the component of the third light can be strengthened. On the other hand, since the luminous efficiency of the photoluminescent layer is reduced, an excitation light source may be supplemented separately. When supplementing the excitation light source separately, a light source that emits light in a wavelength range different from the excitation light may be used instead of the excitation light source 180.

FIG. 105 is a diagram showing an example in which a part of the light emitted from the excitation light source 180 is further used in the configuration shown in FIG. The light emitting device in this example further includes a third optical system (lens) 6520e that introduces a part of the third light emitted from the excitation light source 180 and transmitted through the photoluminescence layer into the third optical fiber 6530c. The first to third optical fibers 6530a, 6530b, 6530c are connected to each other, and in the combiner 6640, which is a connection point, the first and second lights emitted from the light emitting element 100′ and the first light transmitted through the light emitting element 100′. And the light of 3 are combined. Even in such a configuration, the light from the excitation light source 180 can be utilized to generate light having a desired spectrum.

As described above, the light emitting device configured to combine the light in the plurality of wavelength bands emitted from the light emitting element in different directions can be variously modified. In any of the modified examples, the first light and the second light emitted from the light emitting element are combined to obtain light having a desired spectrum.

FIG. 106 is a diagram showing an application example to a home fiber lighting system. This fiber lighting system includes a light emitting device (also referred to as a light source unit) 6400 and a plurality of optical fibers 6530. The light source unit 6400 is installed at a predetermined place in the house, and a plurality of optical fibers 6530 are laid from the light source unit 6400 to the lighting mounting position in each room. The portion depicted as one optical fiber in FIG. 105 may actually be a bundle of a plurality of optical fibers. The configuration of light source unit 6400 is not limited to the configuration described with reference to FIG. 98. The light source unit 6400 shown in FIG. 106 has the same structure as the light emitting device of any of FIGS. Accordingly, similar to the application example described with reference to FIG. 96, desired light is sent to each illumination mounting position and can be used as illumination light. The color and brightness of the illumination light can be changed by changing the composition ratio of light in a plurality of wavelength bands depending on the situation.

According to the aspect described here with reference to FIGS. 97 to 106, the spectrum can be easily adjusted. Therefore, the aspect described here is applicable to the techniques called aesthetic color illumination and chromatic color illumination, similarly to the aspects described with reference to FIGS. 85 to 96. In addition, for example, by using colored illumination, foods such as meat and vegetables look more delicious, scenery such as red flowers and autumn leaves look more vivid, or it is used for distinguishing the freshness of foods. You can also do it.

As described above, conventionally, in the control of the spectrum of light, an optical filter is used to remove an unnecessary wavelength component from the light emitted from the light source. Therefore, the light utilization efficiency is low. On the other hand, the light emitting device of the present disclosure does not need an optical filter because it can enhance and emit light of a specific wavelength. Therefore, the light utilization efficiency can be improved as compared with the conventional light emitting device.

The light emitting element and the light emitting device of the present disclosure can be applied to various optical devices such as a lighting fixture, a display, and a projector.

100, 100a, 100w Light emitting element 110 Photoluminescence layer (waveguide layer)
120, 120', 120a, 120b, 120c Light-transmitting layer (periodic structure, submicron structure)
140 Transparent Substrate 150 Protective Layer 180 Excitation Light Source 200, 210A to 210G Light Emitting Device 202, 206 Condensing Lens 204, 208 Collimating Lens 250 Optical Fiber 300 Housing 300a Opening of Housing 300

Claims (11)

Excitation light source,
A light emitting element arranged on the optical path of the excitation light from the excitation light source,
A first condenser lens disposed on the optical path of the light emitted from the light emitting element,
The light emitting element,
A photoluminescence layer which receives the excitation light and emits light having _a wavelength of λ _{a in} air,
A light-transmitting layer disposed in proximity to the photoluminescent layer ,
At least one of the photoluminescent layer and the transparent layer has a surface structure including at least one of a plurality of convex portions and a plurality of concave portions on the surface ,
The thickness of the photoluminescent layer is such that, in a state where the photoluminescent layer emits the light, inside the photoluminescent layer, the electric field having the maximum amplitude at the positions of the plurality of convex portions or the plurality of concave portions. Is the thickness at which
The light emitting device, wherein the surface structure limits a directivity angle of the light having _a wavelength λ _{a in} the air emitted by the photoluminescent layer. The light is emitted with maximum intensity in a first direction predetermined by the surface structure,
The light emitting device according to claim 1 , wherein an angle between the first direction and a direction in which the light is emitted with an intensity of 50% of the maximum intensity is less than 15° . Let D _int be the distance between two adjacent convex portions or two adjacent concave portions in the surface structure, and n _wav-a be the refractive index of the photoluminescent layer with respect to the light having _a wavelength in air of λ _a. , Λ _a /n _wav-a <D _int <λ _a , the light emitting device of claim 1 or 2. Excitation light source,
A light emitting element arranged on the optical path of the excitation light from the excitation light source,
A first condenser lens disposed on the optical path of the light emitted from the light emitting element,
The light emitting element,
When the excitation light is received, the wavelength in air is λ _a A photoluminescent layer that emits light of
A light-transmitting layer disposed in proximity to the photoluminescent layer,
At least one of the photoluminescent layer and the transparent layer has a surface structure including at least one of a plurality of convex portions and a plurality of concave portions on the surface,
The distance between adjacent convex parts or concave parts is D _int And the refractive index of the photoluminescent layer with respect to the light is n. _wav-a Then λ _a /N _wav-a <D _int <λ _a The relationship of
The light is emitted with maximum intensity in a first direction predetermined by the surface structure,
The light emitting device, wherein an angle between the first direction and a direction in which the light is emitted with an intensity of 50% of the maximum intensity is less than 15°. The surface structure has at least one periodic structure,
When the period of the at least one periodic structure and _{p a, λ a / n wav} -a < relationship p _a <λ _a is satisfied, the light emitting device according to any one of claims 1 to 4. Having arranged collimating lens between the light emitting element and the first condenser lens, the light-emitting device according to any one of claims 1 to 5. It has a connection portion of the optical fiber at a position where the light emitted from the first condenser lens is incident, the light emitting device according to any one of claims 1 to 6. A second focusing lens disposed between said excitation light source light-emitting element, a light-emitting device according to any one of claims 1 to 7. Having arranged collimating lens between said excitation light source light-emitting element, a light-emitting device according to any one of claims 1 to 7. The light emitting device according to claim 8 , further comprising a collimator lens arranged between the excitation light source and the second condenser lens. The photoluminescence layer and said translucent layer are in contact with each other, the light emitting device according to any one of claims 1 to 10.

Images