JP2018169413A - Lighting device and lighting system - Google Patents

Abstract

To provide a lighting device which can implement illumination and image presentation.SOLUTION: A lighting device includes a first projection device 510 and a second projection device 520. The first projection device 510 includes a first light source unit that generates white light. The first projection device 510 emits white light WL, to form a first area LA and a second area DA in the first area LA, having relative low illuminance. The second projection device 520 includes: a second light source unit that generates multiple colors of light; and at least one light-distribution control element disposed in a position where at least one of the multiple colors of light is made incident. The second projection device 520 illuminates at least a part of the second area DA with light PL having at least one of advancing direction and intensity modified by the light-distribution control element, to display an image on the second area DA.SELECTED DRAWING: Figure 36

Description

  The present disclosure relates to a lighting device.

  Projectors are widely used as one of means for sharing information among a plurality of people. For example, a projection device is used as a means for presenting information to participants in scenes such as meetings and lectures. The projection apparatus may be used at home for the purpose of watching movies and the like. For example, Patent Document 1 discloses a projection device that is used by being attached to a ceiling, and has a lighting device on a surface facing a floor surface.

  The projection device does not require a display device such as a display at a location where an image is to be displayed. Therefore, the projection apparatus can display an image on a desired object, and has recently attracted attention as one of means for dynamically presenting information to an individual. In addition, the projection apparatus is attracting attention as a means for providing a stunning effect such as displaying an image of a landscape in a room or coloring a wall surface with light.

  In displaying an image using a projection device, the surrounding illumination is usually turned off. For example, in the projection device described in Patent Document 1 described above, the illumination device provided opposite to the floor surface is turned off when an image is viewed. This is because when illumination light is incident on the displayed image, the contrast ratio of the image is lowered and the image becomes unclear.

JP 2008-185757 A

  However, if the surroundings are darkened when an image is displayed using the projection device, the surroundings become difficult to see. For example, in a meeting situation, it is difficult to read the materials at hand, and the participants of the meeting may feel inconvenience. Thus, conventionally, it has been difficult to achieve both ambient illumination and clear display in a projected image.

  An illumination device according to an embodiment of the present disclosure includes a first light source unit that generates white light, and emits the white light to form a first region and a second region in the first region. A first projection device that forms a second region with relatively low illuminance, a second light source unit that generates light of a plurality of different colors, and at least one of the light of a plurality of different colors is incident At least one first light distribution control element disposed at a position, and the at least one first light distribution control element is changed in at least one of a traveling direction and intensity thereof with the plurality of different color lights. A second projection device that displays an image on the second region by irradiating at least a part of the second region;

  The comprehensive or specific aspect described above may be realized by an instrument, a system, a method, a computer program, a recording medium storing a computer program, or any combination thereof.

  According to an embodiment of the present disclosure, an illumination device that can achieve both illumination and image presentation is provided.

It is a perspective view which shows the structure of the directional light emitting element by a certain embodiment. It is a fragmentary sectional view of the directional light emitting element shown to FIG. 1A. It is a perspective view which shows the structure of the directional light emitting element by other embodiment. It is a fragmentary sectional view of the directional light emitting element shown to FIG. 1C. It is a figure which shows the result of having calculated the increase | augmentation intensity | strength of the light radiate | emitted in a front direction by changing the light emission wavelength and the period of a periodic structure, respectively. It is the graph which illustrated the conditions of m = 1 and m = 3 in Formula (10). It is a figure which shows the result of having calculated the increase | augmentation intensity | strength of the light output to a front direction by changing the light emission wavelength and the thickness t of a photo-luminescence layer. It is a figure which shows the result of having calculated the electric field distribution of the mode guided to x direction when thickness t = 238 nm. It is a figure which shows the result of having calculated the electric field distribution of the mode guided to 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 to x direction when thickness t = 300nm. It is a figure which shows the result of having calculated the light increase intensity | strength about the case where the polarization of light is a TE mode which has an electric field component perpendicular | vertical to ay direction on the same conditions as the calculation of FIG. It is a top view which shows the 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 the two-dimensional periodic structure. It is a figure which shows the result of having calculated the intensification of the light which changes the light emission wavelength and the refractive index of a periodic structure, and outputs it to a front direction. It is a figure which shows the result at the time of setting the film thickness of a photo-luminescence layer to 1000 nm on the conditions similar to FIG. It is a figure which shows the result of having calculated the increase | augmentation intensity | strength of the light which changes the light emission wavelength and the height of a periodic structure, and outputs it to a front direction. 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 calculation similar to the calculation shown in FIG. 9, assuming 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 to 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 photo-luminescence 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. It is a graph which illustrated the conditions of Formula (15). It is a figure which shows the structural example of the light-emitting device 200 provided with the light emitting element 100 shown to FIG. 1A and 1B and the light source 180 which makes excitation light inject into the photo-luminescence layer 110. FIG. 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 factor in the structure of FIG. 17A. It is a figure which shows the wavelength dependence of the light absorption factor 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. FIG. 19B is a diagram illustrating a result of calculating the enhancement of light output in the front direction by changing the emission wavelength and the period of the periodic structure in the configuration of FIG. 19A. It is a figure which shows the structure which mixed several powdery light emitting element. It is a top view which shows the example which arranged the several periodic structure from which a period differs on the photo-luminescence layer in two dimensions. It is a figure which shows an example of the light emitting element which has the structure where the several photo-luminescence layer 110 in which the uneven structure was formed on the surface was laminated | stacked. FIG. 6 is a cross-sectional view illustrating a configuration example in which a protective layer 150 is provided between a photoluminescence layer 110 and a periodic structure 120. It is a figure which shows the example which formed the periodic structure 120 by processing only a part of photo-luminescence 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 of the front direction of the emitted light of the light emitting element made as an experiment. FIG. 4 is a diagram showing a situation where 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. 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 to 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 to FIG. 27A. FIG. 4 is a diagram showing a situation where a 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. 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 to 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 to FIG. 27D. FIG. 4 is a diagram showing a situation where 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. 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 to 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 to FIG. 28A. FIG. 4 is a diagram showing a situation where 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. 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 to 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 to FIG. 28D. It is a graph which shows the result of having measured the angle dependence of the emitted light (wavelength 610nm) of the directional light emitting element made as an experiment. It is a perspective view which shows typically an example of a slab type | mold waveguide. It is a schematic diagram for explaining the relationship between the wavelength of light that receives the light emission enhancement effect and the emission direction in a light emitting device having a periodic structure 120 on the photoluminescence layer. It is a typical top view which shows the example of the structure which arranged the several periodic structure from which the wavelength which shows the light emission enhancing effect differs. It is a typical top view which shows the example of the structure which arranged the several periodic structure from which the direction where the convex part of a one-dimensional periodic structure extends differs. It is a typical top view showing an example of composition which arranged a plurality of two-dimensional periodic structures. It is typical sectional drawing of a directional light emitting element provided with a micro lens. It is typical sectional drawing of the directional light emitting element which has several photo-luminescence layer from which light emission wavelengths differ. It is a typical sectional view of other directional light emitting elements which have a plurality of photo-luminescence layers from which light emission wavelengths differ. It is typical sectional drawing which shows an example of the surface structure which has at least one of a some convex part and a some recessed part. It is a schematic diagram which shows the outline of the example illuminating device which concerns on embodiment of this indication. FIG. 6 is a schematic diagram illustrating an example of an illuminated area LA formed on a wall surface 700. It is a schematic diagram which shows the wall surface 700 of the state irradiated with the white light WL and the projection light PL. It is a schematic diagram which shows the outline of the exemplary structure of the 2nd projector 520. FIG. It is a schematic diagram which shows the specific example of a structure of the 2nd projector 520. FIG. An example of an optical system using a plurality of light sources having different emission wavelengths will be shown. It is a schematic diagram which shows the example of a structure which applied the MEMS mirror as a light distribution control element. FIG. 2 is a schematic diagram showing an outline of an exemplary configuration of a first projection device 510. FIG. 11 is a schematic diagram illustrating an example of a configuration in which a directional light emitting element is applied to a light source unit 511 in a first projection device 510. It is a schematic diagram which shows the modification of the 1st projection apparatus by which the directional light emitting element 100W is arrange | positioned at the light source part 511. FIG. It is a schematic diagram which shows the other modification of the 1st projection apparatus by which the directional light emitting element 100W is arrange | positioned at the light source part 511. FIG. It is the schematic which shows the example of the structure which applied the directional light emitting element to the light source part 521 in the 2nd projector 520. FIG. It is a schematic diagram which shows the specific example of the structure which applied the directional light emitting element to the light source part 521. FIG. It is a schematic diagram which shows the modification of the 2nd projection apparatus by which the directional light emitting element is arrange | positioned at the light source part. It is a schematic diagram which shows the other modification of the 2nd projection apparatus by which the directional light emitting element is arrange | positioned at the light source part 521. FIG. It is a schematic diagram which shows the outline of the other example illuminating device which concerns on embodiment of this indication. It is a schematic diagram which shows the specific example of the optical system in the illuminating device 500B. It is a schematic diagram which shows an example of the structure by which the directional light emitting element is arrange | positioned at the light source part. It is a schematic diagram which shows the modification of the structure by which the directional light emitting element is arrange | positioned at the light source part. It is a typical sectional view showing an example of a room in which an illumination system concerning an embodiment of this indication was installed. It is a figure for demonstrating an example of the control in the illumination system 500S which concerns on embodiment of this indication. It is a schematic diagram which shows the example which applied the illumination system to the house. It is a schematic diagram which shows the example which applied the illumination system to the house. It is a schematic diagram which shows the example which projected the several image. It is a schematic diagram which shows an example of the competition facility which has a lighting system. It is a schematic diagram which shows the example which applied the lighting system to the competition facility.

[1. Outline of Embodiment of Present Disclosure]
The present disclosure includes lighting devices, lighting systems, and facilities described in the following items.

[Item 1]
A first light source unit that generates white light, and a first light distribution control element disposed at a position where the white light is incident. At least one of the traveling direction and the intensity is changed by the first light distribution control element. A first projection device that forms a first region and a second region in the first region and having a relatively low illuminance by emitting white light;
A second light source unit that generates light of a plurality of different colors; and at least one second light distribution control element that is disposed at a position where at least one of the light of a plurality of different colors is incident. A second image is displayed on the second region by irradiating at least a part of the second region with a plurality of different color lights whose at least one of the traveling direction and intensity is changed by the two second light distribution control elements. And a projection device.

[Item 2]
Item 2. The lighting device according to Item 1, wherein the color rendering property of white light is higher than the color rendering property of white light obtained by combining a plurality of lights of different colors.

[Item 3]
The lighting device according to Item 2, wherein the color rendering properties are determined based on JIS Z8726: 1990 or CIE 13.2, 1974.

[Item 4]
At least one of the first light distribution control element and the second light distribution control element is a light modulation element that modulates the intensity of incident light by reflecting or transmitting at least part of the incident light. 4. The illumination device according to any one of 3.

[Item 5]
A first light source unit that generates white light, and a first light distribution control element disposed at a position where the white light is incident. At least one of the traveling direction and the intensity is changed by the first light distribution control element. A first projection device that forms a first region and a second region in the first region and having a relatively low illuminance by emitting white light;
Color light having a second light source unit that generates colored light and a second light distribution control element disposed at a position where the colored light is incident, and at least one of the traveling direction and intensity is changed by the second light distribution control element. An illumination device comprising: a second projection device that displays an image on the second region by irradiating at least a part of the second region.

[Item 6]
At least one of the first light distribution control element and the second light distribution control element is a light modulation element that modulates the intensity of incident light by reflecting or transmitting at least part of the incident light. The lighting device described.

[Item 7]
The first light source unit
A first excitation light source;
A first photoluminescence light emitting element that emits white light in response to the first excitation light from the first excitation light source,
The second light source unit
A second excitation light source;
A second photoluminescent light emitting element comprising a plurality of photoluminescent portions each receiving a second excitation light from a second excitation light source and emitting one of a plurality of different colors of light, from item 1 4. The lighting device according to any one of 4.

[Item 8]
A first optical fiber disposed between the first photoluminescence light-emitting element and the first light distribution control element, and irradiates the first light distribution control element with white light taken in from one end and emitted from the other end. A first optical fiber, and
A plurality of different colored lights that are taken in from one end and emitted from the other end, the at least one second optical fiber disposed between the second photoluminescence light emitting element and the at least one second light distribution control element Item 8. The illumination device according to Item 7, comprising at least one of at least one second optical fiber that irradiates the second light distribution control element with at least one of the first and second light distribution control elements.

[Item 9]
A first optical fiber disposed between a first excitation light source and a first photoluminescence light emitting element, and the first photoluminescence light emitting element is irradiated with the first excitation light taken in from one end and emitted from the other end. A first optical fiber, and
A second optical fiber disposed between the second excitation light source and the second photoluminescence light emitting element, and the second photoluminescence light emitting element is irradiated with the second excitation light taken in from one end and emitted from the other end. Item 9. The lighting device according to item 7 or 8, comprising at least one of the second optical fibers.

[Item 10]
A light source unit that independently emits white light and light of different colors;
A light distribution control element arranged at a position where white light and a plurality of light of different colors are incident,
By emitting white light in which at least one of the traveling direction and intensity is changed by the light distribution control element, the first region and the second region in the first region, the second region having relatively low illuminance And an image is displayed on the second region by emitting light of a plurality of different colors whose at least one of the traveling direction and intensity is changed by the light distribution control element.

[Item 11]
Item 11. The lighting device according to Item 10, wherein the color rendering property of white light is higher than the color rendering property of white light obtained by combining a plurality of lights of different colors.

[Item 12]
12. The lighting device according to item 11, wherein the color rendering properties are determined based on JIS Z8726: 1990 or CIE 13.2, 1974.

[Item 13]
Item 12. The illumination device according to any one of Items 10 to 11, wherein the light distribution control element is a light modulation element that modulates the intensity of incident light by reflecting or transmitting at least part of the incident light.

[Item 14]
The light source
An excitation light source;
A photoluminescence light emitting element that emits light in response to excitation light from an excitation light source,
Photoluminescence light emitting element
A first photoluminescence portion that emits white light upon receiving excitation light;
14. A lighting device according to any of items 10 to 13, comprising a second photoluminescent portion that receives excitation light and emits one of a plurality of different colored lights.

[Item 15]
An optical fiber disposed between a photoluminescence light emitting element and a light distribution control element, which irradiates the light distribution control element with white light and a plurality of different color lights that are taken in from one end and emitted from the other end Item 15. The lighting device according to Item 14.

[Item 16]
Item 14. The optical fiber disposed between the excitation light source and the photoluminescence light-emitting element, the optical fiber configured to irradiate the photoluminescence light-emitting element with excitation light taken in from one end and emitted from the other end. Lighting equipment.

[Item 17]
The second photoluminescence light emitting element is
A photoluminescence layer that receives the second excitation light and emits light having _a wavelength λ _{a in} the air;
A translucent layer disposed proximate to the photoluminescence layer;
A surface structure formed on at least one surface of the photoluminescence layer and the translucent layer and including at least one of a plurality of convex portions and a plurality of concave portions,
10. The lighting device according to any one of items 7 to 9, wherein the surface structure limits a directivity angle of light having _a wavelength λ _{a in} the air emitted from the photoluminescence layer.

[Item 18]
The second photoluminescence portion of the photoluminescence light emitting element is
A photoluminescence layer that emits light having _a wavelength λ _{a in} the air in response to excitation light;
A translucent layer disposed proximate to the photoluminescence layer;
A surface structure formed on at least one surface of the photoluminescence layer and the translucent layer and including at least one of a plurality of convex portions and a plurality of concave portions,
Item 17. The illumination device according to any one of Items 14 to 16, wherein the surface structure limits a directivity angle of light having _a wavelength λ _{a in} the air emitted from the photoluminescence layer.

[Item 19]
The second photoluminescence light emitting element is
A translucent 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 disposed in the vicinity of the surface structure and receiving the second excitation light and emitting light having a wavelength of λ _{a in} the air,
10. The lighting device according to any one of items 7 to 9, wherein the surface structure limits a directivity angle of light having _a wavelength λ _{a in} the air emitted from the photoluminescence layer.

[Item 20]
The second photoluminescence portion of the photoluminescence light emitting element is
A translucent 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 disposed in the vicinity of the surface structure and receiving excitation light and emitting light having a wavelength of λ _{a in} the air;
Item 17. The illumination device according to any one of Items 14 to 16, wherein the surface structure limits a directivity angle of light having _a wavelength λ _{a in} the air emitted from the photoluminescence layer.

[Item 21]
The second photoluminescence light emitting element is
A photoluminescence layer that receives the second excitation light and emits light having _a wavelength λ _{a in} the air;
A translucent layer having a higher refractive index than the photoluminescence 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,
10. The lighting device according to any one of items 7 to 9, wherein the surface structure limits a directivity angle of light having _a wavelength λ _{a in} the air emitted from the photoluminescence layer.

[Item 22]
The second photoluminescence portion of the photoluminescence light emitting element is
A photoluminescence layer that emits light having _a wavelength λ _{a in} the air in response to excitation light;
A translucent layer having a higher refractive index than the photoluminescence 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,
Item 17. The illumination device according to any one of Items 14 to 16, wherein the surface structure limits a directivity angle of light having _a wavelength λ _{a in} the air emitted from the photoluminescence layer.

[Item 23]
Item 23. The lighting device according to any one of items 17 to 22, wherein the photoluminescence layer and the light-transmitting layer are in contact with each other.

[Item 24]
The second photoluminescence light emitting element is
A photoluminescence layer that receives the second excitation light and emits light having _a wavelength λ _{a in} the air;
A surface structure formed on the surface of the photoluminescence layer and including at least one of a plurality of convex portions and a plurality of concave portions, and
10. The lighting device according to any one of items 7 to 9, wherein the surface structure limits a directivity angle of light having _a wavelength λ _{a in} the air emitted from the photoluminescence layer.

[Item 25]
The second photoluminescence portion of the photoluminescence light emitting element is
A photoluminescence layer that emits light having _a wavelength λ _{a in} the air in response to excitation light;
A surface structure formed on the surface of the photoluminescence layer and including at least one of a plurality of convex portions and a plurality of concave portions, and
Item 17. The illumination device according to any one of Items 14 to 16, wherein the surface structure limits a directivity angle of light having _a wavelength λ _{a in} the air emitted from the photoluminescence layer.

[Item 26]
The surface structure has a pseudo-waveguide mode that maximizes the intensity of light having _a wavelength of λ _{a in} the air emitted from the photoluminescence layer in a first direction predetermined by the surface structure. 26. The lighting device according to any one of items 17 to 25,

[Item 27]
27. The projection device according to any one of items 17 to 26, wherein the surface structure limits a directivity angle of light having _a wavelength λ _{a in} the air emitted from the photoluminescence layer to less than 15 °.

[Item 28]
If the distance between two adjacent convex portions or two adjacent concave portions in the surface structure is D _int and the refractive index of the photoluminescence layer with respect to light having _a wavelength of λ _a in the air is n _wav-a , λ _a The lighting device according to any one of items 17 to 27, wherein _a relationship of / n _wav-a <D _int <λ _a is established.

[Item 29]
The surface structure has at least one periodic structure;
The period of at least one periodic structure and p _a, and the refractive index of the photoluminescence layer wavelength in air to light of lambda _a and _{n wav-a, λ a /} n wav-a < a p _{a <λ a} 29. The lighting device according to any one of items 17 to 28, wherein the relationship is established.

[Item 30]
An illumination system including a first illumination device and a second illumination device,
Each of the first lighting device and the second lighting device is the lighting device according to any one of items 1 to 29,
At least one of the 1st field or the 2nd field in the 1st lighting device has an overlap with at least one of the 1st field or the 2nd field in the 2nd lighting device.

[Item 31]
Floor surface,
The ceiling,
One or more walls connecting the floor and the ceiling;
A lighting system including a plurality of light emitting portions provided on at least one of a floor surface, a ceiling, and a wall surface; and
Lighting system
A light source unit that independently emits white light and light of different colors;
A light modulation element disposed inside each of the plurality of light emitting portions;
A plurality of optical fibers disposed between the plurality of light emitting units and the light source unit, wherein the plurality of optical fibers transmit white light and a plurality of different color lights to each of the plurality of light emitting units. ,
Each of the light modulation elements modulates white light and a plurality of different colors emitted from the corresponding optical fiber among the plurality of optical fibers,
Each of the plurality of light emitting units emits modulated white light, thereby forming a first region and a second region in the first region that has a relatively low illuminance. A facility that displays an image on the second region by emitting a plurality of modulated light beams having different colors.

[Item 32]
Item 32. The facility according to Item 31, wherein the color rendering property of white light is higher than the color rendering property of white light obtained by combining light of a plurality of different colors.

[Item 33]
Item 33. The lighting device according to Item 32, wherein the color rendering properties are determined based on JIS Z8726: 1990 or CIE 13.2, 1974.

[Item 34]
A competition facility with a field where the competition takes place,
Field and
A spectator seat surrounding at least a part of the periphery of the field,
A lighting system including a plurality of lighting units disposed above the spectator seat;
One or more pillars supporting a plurality of lighting units;
Lighting system
A light source unit that independently emits white light and light of different colors;
A light modulation element disposed inside each of the plurality of lighting units;
A plurality of optical fibers disposed between the plurality of illumination units and the light source unit, the plurality of optical fibers transmitting white light and a plurality of different color lights to each of the plurality of illumination units,
Each of the light modulation elements modulates white light and a plurality of different colors emitted from the corresponding optical fiber among the plurality of optical fibers,
Each of the plurality of lighting units emits modulated white light, thereby causing a first region and a second region in the first region, which is a second region having a relatively low illuminance, to be at least in the field. A competition facility that displays an image on a second region by emitting a plurality of light beams of different colors formed and modulated in part.

[Item 35]
35. A competition facility according to item 34, wherein the color rendering property of white light is higher than the color rendering property of white light obtained by combining light of a plurality of different colors.

[Item 36]
36. The lighting device according to item 35, wherein the color rendering properties are determined based on JIS Z8726: 1990 or CIE 13.2, 1974.

[2. First Embodiment of Lighting Device]
FIG. 36 schematically illustrates an exemplary illumination device according to an embodiment of the present disclosure. The illumination device 500A shown in FIG. 36 schematically includes a first projection device 510 that emits white light and a second projection device 520 that emits projection light. As will be described later, white light with high color rendering properties is used as the white light WL emitted from the first projection device 510. The projection light PL emitted from the second projection device 520 forms an image on the surface of the object by irradiating the object (for example, a wall surface).

  In the configuration illustrated in FIG. 36, lighting device 500A further includes a control circuit 530, an input / output interface 540, and a sensor 550. Details of the configuration and operation of these units will be described later.

  In the example shown in FIG. 36, the wall surface 700 is irradiated with the white light WL emitted from the first projection device 510 and the projection light PL emitted from the second projection device 520. In the following, for the sake of simplicity, the description will be made assuming that light from other light sources is not incident on the wall surface 700 unless otherwise specified. As will be described in detail later, the projection light PL is light whose traveling direction and / or intensity has been changed by a light distribution control element disposed in the projection apparatus 520. The white light WL emitted from the projection device 510 can be light with relatively high directivity.

  The first projection device 510 forms an illuminated area LA irradiated with the white light WL on the target by irradiating the object to be irradiated (the wall surface 700 in this case) with the white light WL. At this time, the first projection device 510 forms a dark area DA with relatively low illuminance in the illuminated area LA. The dark area DA may be an area that is not irradiated with the white light WL. That is, the illuminated area LA may include an area where the white light WL is not incident as a part thereof. Hereinafter, a portion of the illuminated area LA other than the dark area DA is referred to as a bright area BA. In the dark area DA and the bright area BA, the illuminance of the white light WL is different from each other.

  FIG. 37 schematically shows an example of the illuminated area LA formed on the wall surface 700. FIG. 37 shows a state in which the projection light PL is not irradiated on the wall surface 700 for convenience of explanation. As schematically shown in FIG. 37, the bright area BA is an area where the illuminance of the white light WL is relatively high in the illuminated area LA. The dark area DA is an area formed in the illuminated area LA where the illuminance of the white light WL is relatively low. The projection device 510 emits white light WL, thereby forming an illuminance distribution in which the illuminance of a part of the illuminated area LA is selectively reduced. Such an illuminance distribution is, for example, an object to be irradiated with white light whose traveling direction and / or intensity has been changed by the light distribution control element arranged in the projection device 520 as white light WL (here, the wall surface 700). ).

  FIG. 38 schematically shows an example of a wall surface 700 irradiated with white light WL and projection light PL. FIG. 38 schematically shows a part of the wall 700 in which the white light WL and the projection light PL are incident. The projection light PL emitted from the projection device 520 is irradiated onto at least a part of the dark area DA. Projection light PL typically includes light of a plurality of colors. As the projection light PL is irradiated onto the dark area DA, an image is formed on the dark area DA as shown in FIG. As described with reference to FIG. 37, the illuminance of the white light WL in the dark area DA is lower than that in the bright area BA. Therefore, a clear image with a high contrast ratio can be displayed in the dark area DA.

  Note that “image” in this specification includes still images and moving images. The content presented by the “image” can be, for example, various displays such as image data, animation, documents, signs, or guidance acquired by the imaging device. In the example shown in FIG. 38, an empty landscape, the current time and temperature are displayed on the dark area DA. According to the present disclosure, since it is possible to perform display with a high contrast ratio, even when characters, numbers, and the like are displayed, they are easy to read. The image displayed on the dark area DA may include information transmitted to a specific individual.

  As described above, in the embodiment of the present disclosure, the dark area DA with relatively low illuminance is formed in the spot of the white light WL (illuminated area LA), and an image is projected onto the dark area DA. By projecting an image so as to be superimposed on a region where the illuminance of the white light WL is relatively low, display with a high contrast ratio can be performed. Therefore, the dark area DA can be used as an information display area, for example.

  On the other hand, no image is basically displayed in the bright area BA excluding the dark area DA among the spots of the white light WL. The projection device 510 in the embodiment of the present disclosure emits white light with high color rendering properties. Therefore, light for forming the bright area BA (that is, at least part of the white light WL) can be used as illumination light. In other words, the illumination device according to the embodiment of the present disclosure also has a function as general illumination.

  Here, the color rendering property of white light in the present disclosure will be described. The color rendering property is defined by the JIS standard Z8726: 1990, which is a method for evaluating the color rendering property of a light source, or the CIE (Commission Internationale de l'Eclairage) standard: Method of Measuring and Specifying Color Rendering Properties of Light Sources. , 2nd Edition, CIE13.2, 1974. In the evaluation using the JIS standard Z8726: 1990, the average color rendering index Ra of the white light WL can be 80 or more.

  Thus, according to the embodiment of the present disclosure, it is possible to display an image on an object while illuminating the object. In particular, if a large number of lighting devices according to embodiments of the present disclosure are arranged instead of general lighting, clear images can be displayed in various places without darkening the surroundings. When the object is a surface such as a wall, floor, or desk near the moving person, a mechanism for recognizing and tracking the person may be introduced. As a result, it is possible to dynamically display information in any place while performing illumination.

[3. Example of Projector Configuration]
Hereinafter, specific examples of configurations of the first projection device 510 and the second projection device 520 will be described. As described above, the second projection device 520 emits the projection light PL for displaying an image on the object. The same principle as that of a projector having a known configuration can be applied to display an image in the illumination device of the present disclosure. Hereinafter, prior to the description of the configuration example of the first projection device 510, an example of the configuration of the second projection device 520 will be described first.

[3-1. Configuration example of second projection apparatus]
FIG. 39 shows an outline of an exemplary configuration of the second projection device 520. As illustrated, the second projection device 520 includes a light source unit 521 and a light distribution control unit 526. As will be described later, the light distribution control unit 526 includes one or more light distribution control elements. In the example illustrated in FIG. 39, the projection device 520 includes a projection lens 528 that receives light emitted from the light distribution control unit 526. The light source unit 521 includes a light source 522 and a color separation unit 530, and generates a plurality of light of different colors. Typical examples of light of a plurality of colors generated by the light source unit 521 are red light, green light, and blue light.

  FIG. 40 shows a specific example of the configuration of the second projection device 520. The configuration illustrated in FIG. 40 is an example in which the dichroic mirror 530d and the mirror 530m are used for the color separation unit 530, and the liquid crystal panels 526r, 526g and 526b and the dichroic prism 526p are used for the light distribution control unit 526. As the light source 522, for example, a xenon lamp, a halogen lamp, a metal halide lamp, an ultrahigh pressure mercury lamp, or the like is used. A white LED may be used as the light source 522.

  The light emitted from the light source 522 is separated into red light Rr, green light Rg, and blue light Rb by two dichroic mirrors 530d. These red light Rr, green light Rg, and blue light Rb are incident on liquid crystal panels 526r, 526g, and 526b as light distribution control elements, respectively. The red light Rr, the green light Rg, and the blue light Rb are subjected to intensity modulation by passing through the corresponding liquid crystal panels. Due to the intensity modulation, image information corresponding to each color is superimposed on the red light Rr, the green light Rg, and the blue light Rb. The liquid crystal panels 526r, 526g, and 526b are examples of light modulation elements that modulate the intensity of incident light by reflecting or transmitting at least part of the incident light. LCOS (Liquid Crystal on Silicon) can also be used as the light modulation element. Thus, “light distribution control” in this specification includes modulation of light intensity. The “light distribution control” in this specification includes a change in the traveling direction of light, which will be described later.

  The modulated red light Rr, green light Rg, and blue light Rb enter the dichroic prism 526p. The red light Rr, the green light Rg, and the blue light Rb incident on the dichroic prism 526p are combined by the dichroic prism 526p, and then irradiated to the dark area DA (see FIG. 37) via the projection lens 528, and on the dark area DA. To form a color image. The light of the plurality of colors generated by the light source unit 521 is not limited to the red light Rr, the green light Rg, and the blue light Rb, and may be a combination of other colors.

  The configuration described with reference to FIG. 40 is an example of a so-called three-plate optical system. Of course, it is also possible to apply a so-called single-plate type optical system. In this case, the number of liquid crystal panels as the light distribution control element may be one. In the single-plate optical system, the color filter of the liquid crystal panel corresponds to the color separation unit 530. Note that in the case where it is not necessary to display a color image, for example, when drawing characters in a single color, a light source that generates colored light, such as an LED or a laser diode having a peak at a certain wavelength, may be used as the light source 522. In this case, the color separation unit 530 can be omitted.

  A plurality of light sources having different peak positions in the emission spectrum may be used. In this case, the color separation unit 530 can be omitted from the light source unit 521. FIG. 41 shows an example of a configuration using a plurality of light sources having different emission wavelengths. In the configuration illustrated in FIG. 41, the light source unit 521A includes an LED 522r that emits red light Rr, an LED 522g that emits green light Rg, and an LED 522b that emits blue light Rb. In this example, a digital micromirror device (DMD) 526d is disposed as a light distribution control element. That is, as the projection device 520, a DLP (Digital Light Processing) type projection device may be used.

  The DMD 526d includes a substrate 26s and a large number of minute mirrors 26m arranged on the substrate 26s, and forms an image by reflecting light incident on each mirror 26m in a predetermined direction. In FIG. 41, for simplicity, two of the mirrors 26m arranged in a matrix of, for example, thousands of rows and thousands of columns are illustrated. Each of the mirrors 26m is supported on the substrate 26s so that the inclination of the mirror 26m can be changed by an actuator (not shown), and the inclination of the mirror 26m is changed by about 10 ° according to the input signal. Each mirror 26m changes the traveling direction of the incident light according to its inclination. Specifically, each mirror 26m reflects incident light toward either the projection lens 528 or the light absorber in the projection device 520.

  As illustrated, a lens system 532 is disposed between the LED 522r, the LED 522g, the LED 522b, and the DMD 526d. The lens system 532 uniformly expands the red light Rr beam, the green light Rg beam, and the blue light Rb beam to irradiate the digital micromirror device. By irradiating DMD 526d with red light Rr, green light Rg, and blue light Rb in a time sequential manner via lens system 532, a desired color image can be displayed on an irradiation target (for example, a wall surface).

  A MEMS (Micro Electro Mechanical System) mirror may be applied as the light distribution control element. FIG. 42 shows an example of a configuration in which a MEMS mirror is applied as a light distribution control element. In the configuration illustrated in FIG. 42, the MEMS mirror 526m receives light emitted from the light source unit 521. The MEMS mirror 526m 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. 42, the MEMS mirror 526m is a two-dimensional MEMS mirror in which a movable mirror is supported so as to be rotatable around two orthogonal axes (here, an α axis and a β axis). By applying a voltage having an appropriate magnitude as a drive signal to the MEMS mirror 526m for an appropriate time, the movable mirror can be tilted in a desired direction. By controlling the tilt of the movable mirror, it is possible to reflect the incident light toward a desired position on the dark area DA. By making the drive frequencies different with respect to the α axis and the β axis, the light beam reflected by the MEMS mirror 526m can be scanned in the horizontal direction and the vertical direction. Thereby, an image can be formed on the dark area DA.

  In the example shown in FIG. 42, a color wheel 530w is disposed between the light source 522 and the MEMS mirror 526m. The color wheel 530w is rotatably supported in the projection device 520 and is rotated by a driving device (not shown) (for example, a motor). The color of light incident on the MEMS mirror 526m is switched by the rotation of the color wheel 530w. A desired color image can be projected by controlling the tilt of the movable mirror in the MEMS mirror 526m in synchronization with the rotation of the color wheel 530w. The rotation of the color wheel 530w and the tilt of the movable mirror can be controlled based on, for example, a control signal from the control circuit 530 (see FIG. 36).

[3-2. Configuration example of first projection apparatus]
Next, an example of the configuration of the first projection device 510 will be described. FIG. 43 shows an outline of an exemplary configuration of the first projection device 510. As illustrated in FIG. 43, the projection apparatus 510 typically includes a light source unit 511 and a light distribution control unit 516. Similar to the light distribution control unit 526 in the second projection device 520, the light distribution control unit 516 includes a light distribution control element. In the illustrated example, the projection apparatus 510 includes a projection lens 518 that receives light emitted from the light distribution control unit 516. As can be seen from FIG. 43, it can be said that the projection apparatus 510 has a configuration in which the color separation unit 530 is omitted from the configuration of the second projection apparatus 520 described with reference to FIG.

  The light source unit 511 of the projection apparatus 510 includes a light source 512. As the light source 512, a light source similar to the light source unit 522 of the projection device 520 can be used. However, a light source that emits white light with high color rendering properties is selected as the light source 512.

  The white light emitted from the light source unit 511 is changed in the traveling direction and / or intensity by the light distribution control unit 516 and is emitted toward the outside of the projection apparatus 510 as white light WL. The light distribution control unit 516 includes, for example, a liquid crystal panel as a light distribution control element. By reducing the transmittance of a part of the area in the display surface of the liquid crystal panel, it is possible to form a light area BA and a dark area DA (see FIG. 37) having arbitrary shapes on the irradiation target. The light distribution control unit 516 may include a DMD as a light distribution control element. By controlling the tilt of the mirrors of some of the mirrors arranged in a matrix so that the incident light is reflected by the light absorber, a bright region BA of any shape on the object to be irradiated And a dark area DA can be formed.

  The transmittance of each pixel in the liquid crystal panel and the inclination of each mirror in the DMD corresponding to the pixel of the image formed in the dark area DA can be electrically controlled, and the illuminated area LA and illuminated The position, shape and size of the dark area DA in the area LA can be easily changed. The transmittance of each pixel in the liquid crystal panel or the inclination of each mirror in the DMD is changed based on, for example, a control signal from the control circuit 530 (see FIG. 36).

  In the example shown in FIG. 37, the shapes of the illuminated area LA and the dark area DA are rectangular. However, the shapes of the illuminated area LA and the dark area DA are not limited to this example. It is not necessary that the entire circumference of the dark area DA is surrounded by the bright area BA. For example, the dark area DA may reach the outer edge of the illuminated area LA. That is, the illuminated area LA may be C-shaped, L-shaped, or the like. The illuminated area LA may be separated into a plurality of portions by the dark area DA. A plurality of illuminated areas LA and a plurality of dark areas DA may be formed by the illumination device 500A. That is, the number of illuminated areas LA and the number of dark areas DA formed by a single lighting device 500A are not limited to one. Thus, the pattern of the dark area DA and the bright area BA can be arbitrarily set.

  Even when a general projection apparatus is used, it is possible to display an image on an irradiation target and irradiate the periphery of the image with white light. However, in a general projection apparatus, even when a white light source is used, white light generated by combining light of a plurality of colors is used to express white. For example, in the configuration shown in FIG. 40, red light Rr, green light Rg, and blue light Rb are generated from light emitted from a white light source, and an image is formed using red light Rr, green light Rg, and blue light Rb. . This is because it is advantageous to use monochromatic light with high purity in order to improve color reproducibility. For this reason, the spectrum of light emitted from a general projector has, for example, peaks characteristic of red, green, and blue wavelengths, and has lower color rendering than white light emitted from a white light source. . For this reason, white light emitted from a general projector is not suitable for illumination light.

  On the other hand, the white light WL emitted from the projection device 510 is not light obtained by combining light of a plurality of colors, and thus has high color rendering properties and is suitable for illumination light. In other words, the white light WL emitted to the outside of the first projection device 510 is more than the white light synthesized by the light sources 521 of the second projection device 520 combined. Is also highly color-rendering. According to the present embodiment, the lighting device includes the first projection device that emits white light and the second projection device that emits projection light. Therefore, a clear image can be provided to a person who observes the image. Note that the first projection device and the second projection device may be arranged at separate positions as long as an image can be projected onto the dark area DA. The relationship between the arrangement of the first projection device and the second projection device, and the direction connecting the first projection device and the irradiation target and the direction connecting the second projection device and the irradiation target are permanent. It does not have to be fixed.

[3-3. Configuration example using directional light-emitting elements]
The present inventors have completed a novel light-emitting element (hereinafter sometimes referred to as “directional light-emitting element”) capable of controlling luminance, directivity, or polarization characteristics. The directional light-emitting element found by the present inventors is a photoluminescence light-emitting element having a photoluminescence layer that emits light upon receiving excitation light. The directional light-emitting element has a novel structure that can strongly emit light of a specific wavelength in a specific direction. Details of the structure of the directional light emitting element will be described later. Such a directional light-emitting element may be applied to the light source unit 511 in the first projection device 510 or the light source unit 521 in the second projection device 520.

  FIG. 44 shows an outline of an example of a configuration in which a directional light emitting element is applied to the light source unit 511 in the first projection device 510. In the configuration illustrated in FIG. 44, the light source unit 511 includes an excitation light source 512e and a directional light emitting element 100W that receives excitation light from the excitation light source 512e. The directional light emitting element 100W emits white light upon receiving excitation light from the excitation light source 512e. Examples of the excitation light source 512e are an LED and a laser diode. As the directional light emitting element 100W, for example, a light emitting element (for example, the light emitting element 100) whose structure will be described in detail later can be used. The directional light emitting device 100W may have a substrate that supports the photoluminescence layer. In this example, white light WL is obtained by making light emitted from the directional light emitting element 100 </ b> W enter the light distribution control unit 516. As described above, the directional light emitting element can strongly emit light having a specific wavelength in a specific direction. A method of extracting white light from the directional light emitting element will be described in detail later together with the details of the structure of the directional light emitting element.

  FIG. 45 shows a modification of the first projection device in which the directional light emitting element 100W is arranged in the light source unit 511. As shown in FIG. 45, an optical fiber 515 that transmits white light emitted from the directional light emitting element 100W may be disposed between the directional light emitting element 100W and the light distribution control unit 516. The directional light emitting element 100W exhibits a light distribution with a reduced directivity angle, unlike a conventional photoluminescence light emitting element. In other words, by using the directional light emitting element 100W, an etendue smaller than that of the conventional photoluminescence light emitting element can be obtained. Therefore, high coupling efficiency is obtained between the directional light emitting element 100W and the optical fiber 515, and the optical fiber 515 can efficiently take in the light emitted from the directional light emitting element 100W from one end. A condensing lens or the like may be disposed between the optical fiber 515 and the directional light emitting element 100W.

  The light emitted from the other end of the optical fiber 515 enters the light distribution control unit 516. As illustrated, another optical component such as a collimator lens 517 may be interposed between the other end of the optical fiber 515 and the light distribution control unit 516. The light emitted from the optical fiber 515 spreads according to the numerical aperture of the optical fiber 515. By arranging the collimating lens 517 between the optical fiber 515 and the light distribution control unit 516, parallel light can be obtained. The light distribution control unit 516 may be disposed at a position where the light emitted from the optical fiber 515 is directly or indirectly incident.

  FIG. 46 shows another modification of the first projection device in which the directional light emitting element 100 </ b> W is disposed in the light source unit 511. As illustrated in FIG. 46, an optical fiber 515 may be disposed between the excitation light source 512e and the directional light emitting element 100W. In this example, it may be said that the light source unit 511 includes the optical fiber 515. The optical fiber 515 takes in the excitation light emitted from the excitation light source 512e from one end and emits the incorporated excitation light from the other end. The directional light emitting element 100W is disposed at a position where the excitation light emitted from the optical fiber 515 is directly or indirectly incident.

  45 and 46, it is easy to arrange the light distribution control unit 516 and the light source unit 511 or the directional light emitting element 100W and the excitation light source 512e separately from each other. Therefore, for example, it is possible to operate such that the light distribution control units 516 are arranged at a plurality of places and the white light from the single light source unit 511 is distributed to each of the plurality of light distribution control units 516 via the optical fiber 515. It is. Alternatively, the directional light emitting element 100W and the light distribution control unit 516 are arranged at a plurality of locations, and the excitation light from the single excitation light source 512e is distributed to each of the plurality of directional light emitting elements 100W via the optical fiber 515. May be.

  A directional light emitting element may be used for the light source unit 521 in the second projection device 520. FIG. 47 shows an outline of an example of a configuration in which a directional light emitting element is applied to the light source unit 521 in the second projection device 520. In the configuration illustrated in FIG. 47, the light source unit 521 includes an excitation light source 522e and a color separation unit 530. The color separation unit 530 includes directional light emitting elements 100r, 100g, and 100b. The directional light emitting elements 100r, 100g, and 100b receive the excitation light from the excitation light source 522e, respectively, and thereby strongly emit the red light Rr, the green light Rg, and the blue light Rb, for example, in the front direction. It is.

  In this example, the red light Rr, the green light Rg, and the blue light Rb are obtained by irradiating each of the directional light emitting elements 100r, 100g, and 100b with the excitation light emitted from the excitation light source 522e. The number of is not limited to one. Corresponding to the directional light emitting elements 100r, 100g, and 100b, an excitation light source for the directional light emitting element 100r, an excitation light source for the directional light emitting element 100g, and an excitation light source for the directional light emitting element 100b are arranged in the light source unit 521. May be. When both the light source unit 511 in the first projection device 510 and the light source unit 521 in the second projection device 520 have directional light emitting elements, the excitation light source is shared between the light source unit 511 and the light source unit 521. You may let them. That is, the directional light emitting element in the light source unit 511 and the directional light emitting element in the light source unit 521 may be excited by excitation light emitted from a single excitation light source.

  FIG. 48 shows a specific example of a configuration in which a directional light emitting element is applied to the light source unit 521. In the configuration illustrated in FIG. 48, a disk-shaped light emitting element 530 a is used as the color separation unit 530. As shown in the drawing, the light emitting element 530a is divided into a plurality of regions along a disc-shaped circumferential direction. Each of the plurality of regions has a structure similar to that of the above-described directional light emitting elements 100r, 100g, and 100b. That is, the light emitting element 530a includes a red light emitting portion that emits red light Rr upon receiving excitation light, a green light emitting portion that emits green light Rg, and a blue light emitting portion that emits blue light Rb.

  The light emitting element 530a is disposed on the optical path of the excitation light so that the excitation light from the excitation light source 522e enters one of the plurality of regions described above. The light emitting element 530a is rotatably supported in the projection device 520 similarly to the color wheel described above. The light emitting element 530a is rotated by a driving device (for example, a motor, not shown in FIG. 48) during operation of the projection device 520. Excitation light emitted from the excitation light source 522e enters one of the directional light emitting elements 100r, 100g, and 100b according to the rotation angle of the light emitting element 530a.

  As described above, the directional light emitting elements 100r, 100g, and 100b receive the excitation light from the excitation light source 522e, and direct the red light Rr, the green light Rg, and the blue light Rb in specific directions (for example, the front direction). And emits strongly. Therefore, by rotating the light emitting element 530a and switching the region where the excitation light is incident, the color of the light emitted to the light distribution control element (here, the DMD 526d) can be temporally changed. The light emitting element 530a may be referred to as a directional light emitting color wheel.

  As described above, the color of the light emitted from the light source unit 521 may be switched over time. Here, an example in which the DMD 526d is applied to the light distribution control unit 526 has been described. However, the present invention is not limited to this example, and the above-described MEMS mirror 526m may be applied to the light distribution control unit 526.

  Similarly to the first projection apparatus 510, an optical fiber may be disposed between the directional light emitting element and the light distribution control unit and / or between the excitation light source and the directional light emitting element. FIG. 49 shows a modification of the second projection device in which a directional light emitting element is disposed in the light source unit 521. As illustrated in FIG. 49, an optical fiber 525 may be disposed between the color separation unit 530 and the light distribution control unit 526. Typically, a collimator lens 527 is disposed between the optical fiber 525 and the light distribution control unit 526. The light transmitted by the optical fiber 525 and incident on the light distribution control unit 526 is emitted to the outside of the projection device 520 through the projection lens 528, for example. When the directional light emitting color wheel 530a described with reference to FIG. 48 is used, the optical fiber 525 transmits light of different colors in a time sequential manner.

  A plurality of optical fibers 525 may be disposed between each directional light emitting element and the light distribution control unit 526 so as to correspond to the directional light emitting elements 100r, 100g, and 100b. In this case, each of the plurality of optical fibers 525 transmits light of a specific wavelength that the directional light emitting element emits strongly in a specific direction.

  FIG. 50 shows another modification of the second projection device in which a directional light emitting element is arranged in the light source unit 521. As illustrated in FIG. 50, an optical fiber 525 may be disposed between the excitation light source 522e and the color separation unit 530. In this example, it can be said that the light source unit 521 includes the optical fiber 525. The optical fiber 525 takes in the excitation light emitted from the excitation light source 522e from one end, and irradiates the directional light emitting elements 100r, 100g, and 100b with the excitation light emitted from the other end in a time sequential manner or simultaneously. A plurality of excitation light sources 522e may be arranged in the light source unit 521 so as to correspond to the directional light emitting elements 100r, 100g, and 100b, and a plurality of optical fibers 525 may be arranged between the excitation light source 522e and each directional light emitting element. Then, by using an optical fiber having a branch as the optical fiber 525, the excitation light from the single excitation light source 522e may be distributed to each directional light emitting element.

[4. Second Embodiment of Lighting Device]
FIG. 51 schematically illustrates an outline of an exemplary illumination device according to another embodiment of the present disclosure. An illumination device 500B illustrated in FIG. 51 includes a light source unit 601 and a light distribution control unit 606 that receives light generated by the light source unit 601. The main difference between the lighting device 500B shown in FIG. 51 and the lighting device 500A described with reference to FIG. 36 is that the lighting device 500B independently emits white light and light of a plurality of colors. It is a point which has the light source part 601 comprised so that. In the configuration illustrated in FIG. 51, operations in the light source unit 601 and the light distribution control unit 606 can be controlled by the control circuit 530.

  FIG. 52 shows a specific example of an optical system in the lighting apparatus 500B. The optical system illustrated in FIG. 52 is an example in which the DMD 606d is applied to the light distribution control unit 606.

  As illustrated in FIG. 52, the optical system in the illumination device 500B may have a configuration similar to the configuration described with reference to FIG. In the configuration illustrated in FIG. 52, the light source unit 601 is common to the configuration of the light source unit 521 illustrated in FIG. 48 in that it includes a light source (excitation light source 602e) and a color separation unit (color separation unit 630). However, in the example shown in FIG. 52, a phosphor wheel 630p is used for the color separation unit 630 instead of the light emitting element 530a.

  The phosphor wheel 630p includes a plurality of regions arranged along a disk-shaped circumferential direction, similar to the light-emitting element 530a described above. The colors of light emitted from the plurality of regions are different from each other. In the example shown in FIG. 52, the phosphor wheel 630p includes a red light emitting portion 630r that emits red light, a green light emitting portion 630g that emits green light, and a blue light emitting portion 630b that emits blue light. For example, the red light emitting portion 630r, the green light emitting portion 630g, and the blue light emitting portion 630b are respectively a phosphor that emits red light upon receiving excitation light, a phosphor that emits green light upon receiving excitation light, and a blue light upon receiving excitation light. It contains a phosphor that emits light. In this case, a light source that emits near ultraviolet rays is used as the excitation light source 602e. When a light source that emits blue light is used as the excitation light source 602e, the blue light emitting portion 630b can be a portion that transmits the excitation light.

  The phosphor wheel 630p further includes a white light emitting portion 630w that receives excitation light and emits white light. The white light emitting portion 630w emits white light having relatively high color rendering properties when irradiated with excitation light. The white light emitting portion 630w is formed by, for example, dispersing a plurality of phosphors having different emission wavelength peak positions in a base material (for example, glass). White light having a relatively high color rendering property can be obtained by using a phosphor that emits red light and a phosphor that emits green light when irradiated with blue light as excitation light. A phosphor that emits red light when irradiated with near ultraviolet rays as excitation light, a phosphor that emits green light, and a phosphor that emits blue light may be used.

  According to such a configuration, by rotating the phosphor wheel 630p and switching the region where the excitation light is incident on the phosphor wheel 630p, the light irradiated on the DMD 606d as the light distribution control element is changed to red light, It is possible to switch between green light, blue light, and white light with high color rendering properties. That is, in the second embodiment, light of a plurality of different colors and white light with high color rendering properties are temporally separated and emitted from the same light source unit 601. The light of a plurality of different colors and the white light are changed in traveling direction by the DMD 606d, and emitted from the illumination device 500B as the projection light PL and the white light WL, respectively (see FIG. 51). From the illumination device 500B, the illuminated area LA and the dark area DA in the illuminated area LA are formed on the irradiation target (here, the wall surface 700) by the white light WL emitted from the illumination apparatus 500B. The point that an image is formed on the dark area DA by the emitted projection light PL is the same as in the first embodiment already described. Instead of the DMD 606d, the above-described MEMS mirror (MEMS mirror 526m, see FIG. 42) or a liquid crystal panel may be applied to the light distribution control unit 606.

  Instead of the phosphor wheel 630p, the above-described directional light emitting color wheel may be used. FIG. 53 shows a specific example of a configuration in which a directional light emitting element is applied to the light source unit 601. The light emitting element 630a shown in FIG. 53 has substantially the same configuration as the light emitting element 530a described with reference to FIG. 48 except that the white light emitting portion 100w is included. The white light emitting portion 100w has the same structure as a directional light emitting element described later. More specifically, the white light emitting portion 100w has a surface structure pattern that limits the directivity angle of the emitted light. As will be described later, for example, by applying a pattern of a surface structure whose period is set so as to emit light in the red, green, and blue wavelength regions strongly in the front direction, white light is emitted from the directional light emitting element. Can be emitted. Improve color rendering in white light by further including a surface structure with a period set so that light in a wavelength range different from the red, green, and blue wavelength ranges is emitted strongly in the front direction in the pattern of the periodic structure Can be.

  Similarly to the first embodiment, an optical fiber may be disposed between the directional light emitting element and the light distribution control unit and / or between the excitation light source and the directional light emitting element. As illustrated in FIG. 53, an optical fiber 605 may be disposed between the light emitting element 630 a serving as the color separation unit 630 and the light distribution control unit 606. The optical fiber 605 transmits white light and a plurality of colors of light emitted from the light emitting element 630 a to the light distribution control unit 606. Alternatively, as shown in FIG. 54, an optical fiber 605 may be disposed between the excitation light source 602e and the light emitting element 630a as the color separation unit 630. In this example, the optical fiber 605 transmits the excitation light emitted from the excitation light source 602e to the light emitting element 630a.

  According to the second embodiment of the present disclosure, similarly to the first embodiment, it is possible to achieve both ambient illumination and a clear display in a projected image. According to the second embodiment of the present disclosure, white light and light of a different color can be independently generated by the same light source unit, so that a smaller illuminating device can be provided.

[5. Example of control in lighting device]
In the configuration illustrated in FIGS. 36 and 51, the lighting device (lighting devices 500A and 500B) includes a control circuit 530 and an input / output interface 540. The input / output interface 540 has a configuration capable of exchanging electrical signals with an external device (for example, a computer or a removable memory), and is wired or wirelessly connected to the external device (for example, a server or a terminal device connected to a network). Image data, control signals, etc. The control circuit 530 typically includes a memory and a CPU, and an image processing circuit such as a digital signal processor (DSP). The control circuit 530 generates an image signal based on the image data (or signal) input via the input / output interface 540. The control circuit 530 controls the operation of each unit in the lighting device based on the input from the input / output interface 540. For example, the control circuit 530 transmits a liquid crystal panel as a light distribution control element, a DMD or MEMS mirror, and a signal for controlling driving of the light source. When the light source unit includes a directional light emitting color wheel, a phosphor wheel, or the like, a signal for controlling the rotation of the wheel can be transmitted from the control circuit 530.

[5-1. Control using sensor output]
As already described, the illumination device of the present disclosure forms a bright area BA in which the illuminance of the white light WL having high color rendering properties is relatively high and a dark area DA in which the illuminance of the white light WL is relatively low, An image is projected on the dark area DA. Typically, the bright area BA is formed so as to surround the dark area DA. In the control circuit 530 in the lighting apparatus 500A according to the first embodiment, the illuminated area including at least a part of the area where the image is projected is irradiated with the white light WL having high color rendering properties, and the image is displayed. The projection device 510 and the projection device 520 are controlled such that the illuminance of the white light WL in the region where the light is projected is relatively lower than the illuminance of the white light WL in the other regions to be illuminated. Similarly, in the control circuit 530 in the illumination device 500B according to the second embodiment, the illuminated area including at least a part of the area where the image is projected is irradiated with the white light WL having high color rendering properties, In addition, control is performed such that the illuminance of the white light WL in the area where the image is projected is relatively lower than the illuminance of the white light WL in the other areas of the illuminated area. In addition to such basic control, various controls are possible. Hereinafter, an example of control by the control circuit 530 will be described. Here, an example of control in lighting device 500B having a simpler configuration will be described. Of course, the same control is possible in the illumination device 500A.

  When the positional relationship between the irradiation target and the illumination device 500B is known in advance, it is relatively easy to selectively irradiate the projection light PL to the dark area DA in the illuminated area LA. Information regarding the positional relationship between the irradiation target and the lighting device 500B may be stored in, for example, a memory in the control circuit 530. As described above, the projection apparatus can basically project an image regardless of a target irradiated with light for forming an image. Therefore, the target of irradiation with the white light WL and the projection light PL is not limited to the wall surface, and may be an arbitrary object. For example, the white light WL and the projection light PL can be applied to a surface of a screen, a ceiling, a floor, a door, a desk, a table, a home appliance, or a portable terminal such as a tablet computer. For this reason, it is assumed that an irradiation target moves or an observer who observes an image moves. That is, the region where the image is to be projected may move. It is beneficial if the area irradiated with the projection light PL can be dynamically changed according to changes in the position and shape of the area where the image is to be projected.

  In the configuration illustrated in FIG. 51, the lighting device 500B includes a sensor 550. The sensor 550 may include an image sensor, a displacement sensor, a camera, and the like. Therefore, for example, by using image recognition in a state where the projection light PL is not irradiated, it is possible to detect the position, size, shape, and the like of a region where the illuminance of the white light WL is low. Based on the detection result of the sensor 550, the control circuit 530 can acquire information related to the area where the image is to be projected, that is, the position of the dark area DA on the irradiation target. The control circuit 530 may control the light source unit 601 and the light distribution control unit 606 so that the projected light PL is irradiated onto the recognized dark area DA.

  The output of the sensor 550 may be used to detect the irradiation target and / or the movement of the observer. By detecting the movement of the irradiation target and / or the observer, the control circuit 530 moves the dark area DA to an area suitable for image display (for example, a flat surface with less gloss), and the dark area DA. It is possible to control the light source unit 601 and the light distribution control unit 606 so that an image is projected on top. By such control, for example, it is possible to move the image so as to follow the movement of the observer.

  The target of irradiation with the white light WL and the projection light PL is not limited to a plane, and may be a solid. The surface irradiated with the white light WL and the projection light PL is not limited to a flat surface, and may be a surface having a curved surface or unevenness. Using the output of the sensor 550, the control circuit 530 may execute detection of a flat surface and correction of an image according to the surface shape and / or color of an irradiation target.

  The output of the sensor 550 may be used to detect the movement of the observer who should present the image. For example, an observer's gesture may be used as an instruction to the lighting device 500B. For example, the control circuit 550 analyzes the observer's gesture and controls the light source unit 601 and the light distribution control unit 606 so as to project an image at a position corresponding to the gesture. Such gesture input may be used as information for authenticating an individual. By performing personal authentication, the lighting device 500B can present information corresponding to each observer.

  Ranging method (contrast detection, phase difference detection, etc.) used in general imaging devices for information acquisition by sensors, distance measuring method using the time to irradiate near infrared rays and detect reflected light Etc. may be combined. The program in which the above-described various control instructions are described can be stored in the memory of the control circuit 530, for example. The processor in the control circuit 530 executes the above-described control by reading a program from the memory, for example.

  Furthermore, as the projection light PL, a predetermined geometric pattern such as a parallel line or a grid is projected, and the projected pattern is acquired as an image, whereby the tilt of the surface irradiated with the projection light PL is obtained. A three-dimensional shape can also be measured. Further, by deforming the projected image according to the tilt and shape of the surface irradiated with the projection light PL, unnatural distortion of the projected image can be eliminated.

[5-2. Control of multiple lighting devices]
A plurality of lighting devices of the present disclosure may be used. By arranging a plurality of lighting devices (lighting devices 500A or 500B) in a space where illumination is desired, the entire space can be illuminated.

  FIG. 55 schematically illustrates an example of a room in which a lighting system according to an embodiment of the present disclosure is installed. In the example shown in FIG. 55, a lighting system 500S including a plurality of lighting devices 500B is installed on a ceiling 710 of a room Rm. In FIG. 55, three illumination devices 500B are shown. However, the number of lighting devices 500B in the lighting system 500S is not limited to three, and the lighting system 500S may include the lighting device 500A according to the first embodiment.

  In the configuration illustrated in FIG. 55, the ceiling 710 is provided with three light emitting portions 712 (for example, openings) so as to correspond to the three illumination devices 500B, respectively. The white light WL and the projection light PL emitted from the illumination device 500B are irradiated toward the floor surface 720. In this example, the entire floor surface 720 is covered with a plurality of illuminated areas LA. As described above, by providing the light emitting unit 712 on at least one of the ceiling, wall surface, and floor surface of a room such as a house, the entire space can be illuminated with the light emitted from the illumination device of the present disclosure. As shown in FIG. 55, it is not necessary for all of the illumination devices included in illumination system 500S to emit both white light WL and projection light PL. The illumination device 500B may be controlled so as to form the dark region DA in the illuminated region LA as necessary and irradiate the projection light PL.

  With reference to FIG. 56, an example of control in the illumination system 500S according to the embodiment of the present disclosure will be described. As described above, in the embodiment of the present disclosure, the spot of the white light WL is formed on the irradiation target, and the dark region DA is formed in the spot. Is used as white light WL. Therefore, as schematically shown in FIG. 56, for example, when the body of the observer 900 is interposed between the illumination device 500B and an irradiation target (here, the floor surface 720), a shadow is generated and projected onto the floor surface 720. A part of the image is lost. At this time, the projection light PL is irradiated onto the body of the observer 900, so that an image is displayed on the body of the observer 900.

  In the example shown in FIG. 56, the illuminated area in the left illumination device 500B is shifted so as to irradiate the area where the projection light PL emitted from the right illumination device 500B is blocked. That is, in this example, the illuminated area in the left illumination device 500B overlaps with the illuminated area in the right illumination device 500B. Furthermore, in the right side lighting device 500B, a portion projected on the body of the observer 900 in the image formed by the projection light PL may be replaced with the bright area BA. Each of the illumination devices included in the illumination system 500S can recognize an illumination area formed by an illumination device different from itself based on the detection result of the sensor 550, for example. The control circuit 530 executes control to change the region irradiated with the white light WL and the region irradiated with the projection light PL in accordance with the recognition result, thereby preventing the image from being lost and the space to be illuminated. It is possible to control the display of the image as a whole. In this way, control may be performed such that two or more lighting devices are interlocked so that some of the plurality of illuminated areas in the lighting system 500S overlap each other. Such control is particularly useful when performing gesture input or the like.

  Note that the control of each lighting device in the lighting system 500S need not be executed by the control circuit of each lighting device. For example, the control of the plurality of lighting devices in the lighting system 500S may be collectively executed by a control circuit that is smaller than the number of the plurality of lighting devices included in the lighting system 500S. By concentrating a control circuit that performs control of a plurality of lighting devices, linked control of the plurality of lighting devices can be facilitated.

[6. Application example of lighting device]
Hereinafter, application examples of the lighting device or the lighting system will be described with reference to the drawings.

  57 and 58 show an example in which the lighting system is applied to a house. FIG. 57 shows an example of a house 800 having a lighting system 510 </ b> S including a light source unit 601. In the configuration illustrated in FIG. 57, the light source unit 601 generates white light WL and projection light PL. The white light WL and the projection light PL generated by the light source unit 601 are distributed to each part in the house 800 and each part in the site via the optical fiber 605. For example, the light transmitted by the optical fiber 605 is applied to a light distribution control element (not shown) disposed in the light emitting unit 712 provided on the ceiling of the room Rm. For example, the white light WL and the projection light PL whose traveling directions are changed by the light distribution control element are emitted toward the inside of the room Rm.

  As in this example, the light source unit that generates the white light WL and the projection light PL may be arranged in one place, and the white light WL and the projection light PL may be transmitted to a desired place by an optical fiber. According to such a configuration, it is possible to design an illumination with a high degree of freedom. As illustrated in FIG. 58, a light distribution control unit 606 may be arranged for each light emitting unit 712. Since the light distribution control element is relatively small, the light emitting unit 712 can be relatively easily downsized. For example, if a conventional downlight is replaced with a light emitting portion 712, it is possible to design an illumination as if the light source is not visible, as shown in FIG.

  FIG. 59 shows an example in which a plurality of images are projected. The illumination device and the illumination system according to the present disclosure have both a general illumination function and a projection device function. Therefore, as shown in FIG. 59, information can be displayed everywhere while the space is illuminated. By projecting scenery, paintings, etc., it is also possible to obtain the effect of space production.

  Furthermore, it is also possible to present information according to individual observers in the space to be illuminated as an image. In the example shown in FIG. 59, the content of the newspaper is projected as an image Ns on the table in front of the observer 900A before going to work, and the dish is displayed on the counter top in front of the observer 900B preparing for breakfast. A recipe is projected as an image Rp. The projection light PL irradiated on the table presents an image Ns with a high contrast ratio to the viewer 900A, and the white light WL irradiated on the table functions as illumination light for the viewer 900B.

  An individual in a space where the light emitting unit 712 (or the lighting devices 500A and 500B) is arranged may be detected, and specific information may be presented to the specific individual according to the detection result. If a plurality of the above-described sensors 550 (for example, see FIG. 55) are arranged in a space to be illuminated, it is possible to specify the position (or flow line) of an individual in the space. For example, whether or not there is a person in a space to be illuminated is detected by an infrared sensor, and when the presence of the person is detected, the person is photographed by a camera. By applying pattern matching or the like to image data acquired by photographing, it is possible to identify an individual in a space where illumination is to be performed. The control circuit 530 (see, for example, FIG. 55) selects image data to be displayed in accordance with the specified individual. Further, the control circuit 530 emits a light source so that the projection light PL for forming the selected image is irradiated to an object (table or countertop in the example shown in FIG. 59) in the vicinity of the identified individual. And driving of the light distribution control unit. At this time, it detects the shape of the surface of the object to be irradiated, whether an object is placed on the object to be irradiated, etc., and corrects the image or changes the location where the image is displayed according to the detection result. Or you may.

  For example, a plurality of light emitting units 712 and a plurality of sensors 550 are installed at the entrance of a house. The control circuit 530 determines whether there is a person at the entrance based on the detection results of the plurality of sensors 550. When it is determined that there is a person at the entrance, the detection results of the plurality of sensors 550 are analyzed to determine a change in the position of the person. The control circuit 530 determines whether the person has come home or is going out based on the information on the change in position. For example, when it is determined that the person has returned home, the control circuit 530 controls the operation of the camera in the sensor 550, and for example, photographs the face of the person who has returned home. The control circuit 530 controls who drives the light source unit and the light distribution control unit so as to identify who in the family has returned home based on the captured data and to display an image corresponding to the person who has returned home. To do. The image to be presented is a table in which the ID assigned to each individual of the family and the type of information to be presented (schedule for the next day, record of visitors, list of senders of mail received that day, etc.) are described Can be determined by referring to the table based on the identified individual ID. The table may describe the type of information to be presented according to each ID when returning home and when going out. Information about each person's behavior pattern (such as the time of going out for each day of the week and the time of returning home) may be stored in a server on the network, a memory in the control circuit 530, or the like. A method for specifying an individual in a space to be illuminated and presenting information corresponding to the individual is disclosed in, for example, Japanese Patent Application Laid-Open No. 2007-086545. For reference, the entire disclosure of Japanese Patent Application Laid-Open No. 2007-086545 is incorporated herein by reference.

  The lighting system 510S may have a connection with a network such as the Internet. For example, an individual in a space to be illuminated may be specified by comparing information acquired by a sensor with information stored in a server on a network. Depending on the authentication result, images such as weather forecasts and news may be presented to the identified individual. Data of an image to be presented may be acquired from a server on the network.

  Presenting such information in response to the observer is particularly useful in the office. For example, regardless of which desk in which room is used, a schedule, necessary business data, and the like can be displayed on the desk according to each individual.

  Note that the lighting system of the present disclosure is not limited to a house and can be applied to a facility. As used herein, “facility” broadly includes workpieces having a floor, a ceiling, and wall surfaces. Examples of facilities are houses, schools, buildings, churches, hotels, hospitals, gymnasiums, stores, factories, airports, concert halls, aquariums, museums, libraries, cinemas, casinos, dome stadiums, station platforms It is a structure. The installation location of the light emitting unit in the illumination system is not limited to a living room, and may be a location that is not continuously used, such as a hallway or a warehouse. If the lighting system of the present disclosure is applied to a public facility, for example, it is possible to present a guide according to a visitor as an image.

  The lighting system of the present disclosure can also be applied to a competition facility. FIG. 60 shows an example of a competition facility having a lighting system. A competition facility 810 shown in FIG. 60 includes a field Fd in which a competition is performed, a spectator seat 812 disposed around the field Fd, a plurality of lighting units 814 disposed above the spectator seat 812, and a plurality of lighting units. And pillars 816 that directly or indirectly support at least one of 814.

  In the configuration illustrated in FIG. 60, the competition facility 810 includes a lighting system 520 </ b> S including a plurality of lighting units 814. The illumination system 520 </ b> S includes a light source unit 601, a light distribution control unit 606 arranged in the illumination unit 814, and a light distribution control element in the light distribution control unit 606 and an optical fiber 605 that optically couples the light source unit 601. It is out. Each of the plurality of illumination units 814 irradiates the field Fd with white light WL and projection light PL. Therefore, the competition facility 810 can display a desired image on the field Fd while illuminating the field Fd.

  FIG. 61 shows an example in which the lighting system is applied to a competition facility. In the example shown in FIG. 61, a profile image Pf corresponding to each player is displayed near the player on the field Fd by the projection light PL emitted from the lighting unit 814. For example, if a plurality of lighting units 814 are arranged so as to overlap between a plurality of illuminated areas, it is easy to move an image in accordance with the movement of each player. Thus, by displaying an image on the field Fd, the spectator can obtain information on the players in real time, and can enjoy the competition more. A line indicating the world record may be displayed on the field Fd instead of the profile image Pf or together with the profile image Pf. For example, an image of an advertisement may be displayed on the field Fd using the projection light PL.

  The term “competition” in this specification widely includes ball games such as baseball and soccer, athletics, ice competition, water competition, vehicle / ship competition, snow competition, equestrian competition, gymnastic competition, various public competitions, and the like. “Sports” in this specification includes mind sports.

[7. Directional light emitting device]
Hereinafter, the directional light emitting device will be described in detail.

The directional light emitting element includes a photoluminescence layer that receives excitation light and emits light having _a wavelength of λ _{a in} the air. As will be described in detail later, the directional light-emitting element has a novel structure capable of controlling the light emission efficiency, directivity, or polarization characteristics of the photoluminescent material.

A directional light emitting device according to an aspect is formed on a surface of at least one of a photoluminescence layer, a light transmission layer disposed in proximity to the photoluminescence layer, the photoluminescence layer and the light transmission layer, and a plurality of protrusions and And a surface structure including at least one of the plurality of recesses. This surface structure limits the directivity angle of light emitted from the photoluminescence layer and having a wavelength λ _{a in} the air. The surface structure may be a submicron structure that extends in the plane of the photoluminescent layer or the light transmissive layer. The submicron structure may be a periodic structure including at least one of a convex portion or a concave portion, for example. The submicron structure includes, for example, a plurality of convex portions or a plurality of concave portions, a distance between adjacent convex portions or concave portions is D _int, and the light emitted from the photoluminescence layer has a wavelength of λ _a in the air. The relationship of λ _a / n _wav-a <D _int <λ _a is established, where n _wav-a is the refractive index of the photoluminescence layer with respect to the first light. Alternatively, when the period of the periodic structure and _{p a, λ a / n wav} -a <p a <λ relationship _a holds. The wavelength λ _a is, for example, in the wavelength range of visible light (for example, 380 nm to 780 nm). In applications that use infrared, the wavelength λ _a may exceed 780 nm. On the other hand, in applications using ultraviolet light, the wavelength λ _a may be less than 380 nm. In this disclosure, electromagnetic waves in general including infrared rays and ultraviolet rays are expressed as “light” for convenience.

  The photoluminescent layer includes a photoluminescent material. The photoluminescent material means a material that emits light upon receiving excitation light. The photoluminescent material includes a fluorescent material and a phosphorescent material in a narrow sense, includes not only an inorganic material but also an organic material (for example, a dye), and further includes a quantum dot (that is, a semiconductor fine particle). 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 light-transmitting layer disposed in the vicinity of the photoluminescence layer is formed of a material having a high transmittance with respect to light emitted from the photoluminescence layer, for example, an inorganic material or a resin. The light transmitting layer can be formed of, for example, a dielectric (particularly, an insulator that absorbs little light). The light transmissive layer may be, for example, a substrate that supports the photoluminescence layer. When the air-side surface of the photoluminescence layer 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 at least one surface of the photoluminescence layer and the light transmitting layer. Here, the “surface” means a portion in contact with another substance (that is, an interface). When the light-transmitting layer is a gas layer such as air, the interface between the gas layer and another substance (for example, a photoluminescence layer) is the surface of the light-transmitting 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 or two dimensions. Such a surface structure can be referred to as a “periodic structure”. The plurality of convex portions and the plurality of concave portions 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 varies in a certain direction. Here, the term “periodic” is not limited to an aspect that is strictly periodic, but includes an aspect that can be said to be approximately periodic. In this specification, among a plurality of continuous convex portions or concave portions, a distance between two adjacent centers (hereinafter sometimes referred to as “center interval”) is any two adjacent convex portions or concave portions. Is also considered to be a periodic structure having a period p when it falls within a range of ± 15% of a certain value p.

  In the present specification, the “convex portion” means a raised portion with respect to a reference height portion. The “recessed portion” means a recessed portion with respect to a reference height portion. Depending on the shape, size, and distribution of the convex and concave portions, it may not be easy to determine which is the convex portion and which is the concave portion. For example, in the cross-sectional view shown in FIG. 35, 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, it can be said that each of the member 610 and the member 620 has at least one of a plurality of convex portions and concave portions.

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 from the photoluminescence layer in the air. . When the light emitted from the photoluminescence layer is visible light, short-wavelength near infrared light, or ultraviolet light, 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 “submicron structure” may include a portion having a central interval or period exceeding 1 micrometer (μm) in part. In the following description, a photoluminescence layer that emits visible light is mainly assumed, and the term “submicron structure” is mainly used as a term meaning a surface structure. However, the following discussion holds true for the surface structure having a fine structure exceeding the sub-micron order (for example, a fine structure of the micron order used in applications using infrared rays).

  In the directional light emitting device, as will be described in detail later with reference to calculation results and experimental results, a unique electric field distribution is formed inside the photoluminescence layer and the light transmission layer. This is formed by the guided light interacting with the submicron structure (ie, the surface structure). The mode of light forming such an electric field distribution can be expressed as a “pseudo-waveguide mode”. By utilizing this pseudo waveguide mode, as described below, it is possible to obtain the effects of increased photoluminescence emission efficiency, improved directivity, and polarization selectivity. In the following description, the term pseudo-waveguide mode may be used to describe a new configuration and / or a new mechanism found by the present inventors. The description is merely one illustrative description and should not limit the present disclosure in any way.

The submicron structure includes, for example, a plurality of convex portions, and can satisfy the relationship of λ _a / n _wav−a <D _int <λ _a where D _int is the distance between the centers of adjacent convex portions. The submicron structure may include a plurality of concave portions instead of the plurality of convex portions. Hereinafter, for the sake of simplicity, the submicron structure will be described as having a plurality of convex portions. λ represents the wavelength of light, and λ _a represents the wavelength of light in the air. n _wav is the refractive index of the photoluminescence 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 by the respective volume ratio is _defined as n _wav . Since generally the refractive index n depends on the wavelength, that is a refractive index to light of lambda _a it is desirable to express the n _wav-a, may be omitted for simplicity. n _wav is basically the refractive index of the photoluminescence layer. When the refractive index of the layer adjacent to the photoluminescence layer is larger than the refractive index of the photoluminescence layer, the refractive index and the photoluminescence of the layer having the larger refractive index are used. Let n _{wav be the} average refractive index obtained by weighting the refractive indices of the layers by their respective volume ratios. This is because this is optically equivalent to the case where the photoluminescence layer is composed of a plurality of layers of different materials.

When the effective refractive index of the medium with respect to the light in the pseudo waveguide mode is n _eff , n _a <n _eff <n _wav is satisfied. Here, n _a is the refractive index of air. Considering that the light in the quasi-waveguide mode propagates while totally reflecting inside the photoluminescence layer at the 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 waveguide 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 translucent layer. In addition, since the electric field distribution varies depending on the polarization direction of the pseudo waveguide mode (TE mode and TM mode), the effective refractive index n _eff may be different between the TE mode and the TM mode.

The submicron structure is formed in at least one of the photoluminescence layer and the light transmission layer. When the photoluminescence layer and the light transmission layer are in contact with each other, a submicron structure may be formed at the interface between the photoluminescence layer and the light transmission layer. At this time, the photoluminescence 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 disposed in the vicinity of the photoluminescence layer. Here, the phrase “the light-transmitting layer (or its submicron structure) is close to the photoluminescence layer” typically means that the distance between them is not more than half the wavelength λ _a . As a result, the electric field of the waveguide mode reaches the submicron structure, and the pseudo waveguide mode is formed. However, when the refractive index of the light-transmitting layer is larger than the refractive index of the photoluminescent layer, the light reaches the light-transmitting layer even if the above relationship is not satisfied. Therefore, the submicron structure of the light-transmitting layer and the photoluminescent layer the distance between the may be more than half of the wavelength lambda _a. In this specification, when the photoluminescence layer and the light-transmitting layer are in a positional relationship such that the electric field of the guided mode reaches a submicron structure and a pseudo-guided mode is formed, the two are associated with each other. Sometimes expressed.

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

If the mechanism as described above is used, the luminous efficiency of photoluminescence increases due to the effect of the electric field being enhanced by the pseudo waveguide mode, and the generated light is coupled to the pseudo waveguide mode. The light of the quasi-waveguide mode is bent at a traveling angle by a diffraction angle defined by the periodic structure. By utilizing this, light of a specific wavelength can be emitted in a specific direction. That is, the directivity is remarkably improved as compared with the case where no periodic structure is present. Further, since the effective refractive index n _eff (= n _wav sin θ) is different between the TE mode and the TM mode, high polarization selectivity can be obtained at the same time. For example, as shown in an experimental example later, it is possible to obtain a light emitting element that emits linearly polarized light (for example, TM mode) having a specific wavelength (for example, 610 nm) strongly in the front direction. At this time, the directivity angle of the light emitted in the front direction is, for example, less than 15 °. Here, “directivity angle” is defined as an angle between the direction in which the intensity is maximum and the direction in which the intensity is 50% of the maximum intensity with respect to 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 °. Thus, 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 λa. In other words, the distribution of light of the wavelength lambda _a, to narrow angle as compared to when there is no periodic structure. Such a light distribution in which the directivity angle is reduced as compared with the case where there is no periodic structure 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 described later, light having _a wavelength λa is slightly emitted also in a direction away from the direction in which the intensity is maximum (for example, 20 ° to 70 °). Overall, however, the emitted light having a wavelength lambda _a is concentrated in the range of 0 ° to 20 °, the orientation 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 specific wavelength of light is diffracted into a plurality of diffracted lights such as zero-order light (that is, transmitted light) and ± first-order diffracted light. The light is emitted separately. In such a diffraction grating, high-order diffracted light is generated on both sides of zero-order light. High-order diffracted light generated on both sides of zero-order light in the diffraction grating makes it difficult to realize narrow-angle light distribution. In other words, the conventional diffraction grating does not have an effect peculiar to the embodiment of the present disclosure in which the directivity angle of light is limited to a predetermined angle (for example, about 15 °). In this regard, the periodic structure according to the embodiment of the present disclosure has properties that are significantly different from those of conventional diffraction gratings.

  When the periodicity of the submicron structure is lowered, the directivity, light emission efficiency, polarization degree, and wavelength selectivity are weakened. What is necessary is just to adjust the periodicity of a submicron structure as needed. The periodic structure may be a one-dimensional periodic structure with high polarization selectivity or a two-dimensional periodic structure capable of reducing the degree of polarization.

  The submicron structure can include a plurality of periodic structures. The plurality of periodic structures have different periods (pitch), for example. Alternatively, the plurality of periodic structures are different from each other in the direction (axis) having periodicity, for example. The plurality of periodic structures may be formed in the same plane or may be stacked. Of course, the light-emitting element has a plurality of photoluminescence layers and a plurality of light-transmitting layers, and these may have a plurality of submicron structures.

The submicron structure can be used not only to control the light emitted from the photoluminescence layer, but also to efficiently guide the excitation light to the photoluminescence layer. That is, the excitation light is diffracted by the submicron structure and coupled to the pseudo-waveguide mode in which the excitation light is guided through the photoluminescence layer and the light transmission layer, so that the photoluminescence layer can be efficiently excited. Λ _ex / n _wav-ex <D _int <λ _ex , where λ _ex is the wavelength of light in the air that excites the photoluminescent material, and n _wav-ex is the refractive index of the photoluminescence layer for this excitation light. A sub-micron structure in which is satisfied may be used. n _wav-ex is the refractive index at the excitation wavelength of the photoluminescent material. If 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 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 within the range of visible light, the excitation light may be emitted together with the light emitted from the photoluminescence layer.

[8. Knowledge discovered by the present inventors]
Before describing the details of the configuration of the directional light emitting element, first, the knowledge found by the present inventors will be described, and then an exemplary configuration of the directional light emitting element will be described. As described above, photoluminescent materials used in fluorescent lamps, white LEDs, and the like emit light isotropically. In order to illuminate a specific direction with light, optical components such as a reflector and a lens are required. However, if the photoluminescence layer itself emits light with directivity, for example, the lens can be made smaller, so that the size of the optical device or instrument can be greatly reduced. Based on such an idea, the present inventors have studied in detail the configuration of the photoluminescence layer in order to obtain directional light emission.

The inventors of the present invention first considered that the light emission itself has a specific directionality so that light from the photoluminescence layer is biased in a specific direction. The light emission rate Γ, which is an index characterizing light emission, is expressed by the following formula (1) according to Fermi's golden rule.

In equation (1), r is a position vector, λ is the wavelength of light, d is a dipole vector, E is an electric field vector, and ρ is a density of states. In many materials except some crystalline materials, 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 light emission rate Γ is constant regardless of the direction. For this reason, in most cases, the photoluminescence layer emits isotropically.

  On the other hand, in order to obtain anisotropic light emission from the formula (1), it is necessary to devise either a dipole vector d aligned in a specific direction or a component in a specific direction of the electric field vector to be enhanced. is there. Directional emission can be realized by any one of these devices. In an embodiment of the present disclosure, a pseudo waveguide mode in which an electric field component in a specific direction is enhanced due to the effect of confining light in the photoluminescence layer is used. The structure for that purpose is examined and the result analyzed in detail is demonstrated below.

[9. Configuration to strengthen only the electric field in a specific direction]
The inventors of the present application considered controlling light emission by using a waveguide mode with a strong electric field. When the waveguide structure itself includes a photoluminescence material, the generated light can be coupled to the waveguide mode. However, if the waveguide structure is simply formed using a photoluminescence material, the emitted light becomes a waveguide mode, so that almost no light is emitted in the front direction. Therefore, the inventors of the present application considered combining a waveguide including a photoluminescent material with a periodic structure. When the periodic structure is close to the waveguide and the light is guided while overlapping the periodic structure, a pseudo waveguide mode exists due to the action of the periodic structure. That is, this pseudo waveguide mode is a waveguide mode limited by the periodic structure, and is characterized in that the antinodes of the electric field amplitude are generated in 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. Furthermore, since this mode interacts with the periodic structure and is converted into propagating light in a specific direction by the diffraction effect, light can be emitted to the outside of the waveguide. Furthermore, since the light other than the pseudo waveguide mode has a small effect of being confined in the waveguide, the electric field is not enhanced. Therefore, most of the light emission is coupled to the pseudo waveguide mode having a large electric field component.

  In other words, the inventors of the present application configure a waveguide having a periodic structure close thereto by a photoluminescence layer containing a photoluminescence material (or a waveguide layer having a photoluminescence layer), thereby generating generated light. We considered to realize a directional light source by coupling to a quasi-guided mode that is converted into propagating light in a specific direction.

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

  Further, when the periodic structure is close to the photoluminescence layer, the pseudo-waveguide mode is formed by the electric field of the waveguide mode interacting with the periodic structure. Even when the photoluminescence layer is composed of a plurality of layers, if the electric field of the waveguide mode reaches the periodic structure, a pseudo waveguide mode is formed. It is not necessary for all of the photoluminescence layer to be a photoluminescence material, and it is sufficient that at least a part of the photoluminescence layer has a function of emitting light.

  When the periodic structure is formed of a metal, a mode based on the waveguide mode and the effect of plasmon resonance is formed. This mode has different properties from the quasi-guided mode described above. In addition, 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 desirable to use a dielectric material with low absorption as the periodic structure.

First, the present inventors form 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. It was 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 light transmitting layer) 120. Hereinafter, when the light transmitting layer has a periodic structure (that is, when a periodic submicron structure is formed in the light transmitting layer), the periodic structure 120 may be referred to as the light transmitting layer 120. In this example, the periodic 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 cross-sectional view of the light emitting device 100 taken along a plane parallel to the xz plane. When the periodic structure 120 having a period p is provided so as to be in contact with the waveguide 110, the pseudo-waveguide mode having the wave number k _wav in the in-plane direction is converted into propagating light outside the waveguide, and the wave number k _out is It can be represented by Formula (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 approximately is a light beam propagating at an angle θ _wav , and the following equations (3) and (4) hold.

In these equations, λ ₀ is the wavelength of light in the 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 exit angle. From the equations (2) to (4), the emission angle θ _out can be expressed by the following equation (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 (ie, the front).

  Based on the above principle, the generated light is coupled to a specific quasi-waveguide mode, and further converted into light having a specific emission angle using a periodic structure, thereby emitting strong light in that direction. It is considered possible.

In order to realize the above situation, there are some constraints. First, in order for the pseudo waveguide mode to exist, it is necessary that the light propagating in the waveguide is totally reflected. The condition for this is expressed by the following formula (6).

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

On the other hand, considering the equation (6), it can be seen that the following equation (8) should be satisfied.

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

From formula (9) and formula (6), it can be seen that the necessary condition is the following formula (10).

When the periodic structure as shown in FIGS. 1A and 1B is provided, the first-order diffracted light with m = 1 should be designed mainly because the high-order diffraction efficiency with m = 2 or higher is low. . For this reason, in the periodic structure in the present embodiment, m = 1 and the period p is determined so as to satisfy the following expression (11) obtained by modifying expression (10).

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

On the other hand, a structure in which the photoluminescence layer 110 and the periodic structure 120 are formed on the transparent substrate 140 as illustrated in FIGS. 1C and 1D may be employed. In this case, determined from the refractive index n _s of the transparent substrate 140 is larger than the refractive index of air, the following equation was n _out = n _s in equation (11) the period p to satisfy (13) do it.

In equations (12) and (13), it is assumed that m = 1 in equation (10), but m ≧ 2 may be satisfied. That is, when both surfaces of the light emitting element 100 are in contact with the air layer as shown in FIGS. 1A and 1B, the period p is set so that m is an integer of 1 or more and the following expression (14) is satisfied. It only has to be done.

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

  By determining the period p of the periodic structure so as to satisfy the above inequality, light generated from the photoluminescence layer 110 can be emitted in the front direction, so that a light emitting element having directivity can be realized.

[10. Verification by calculation]
[10-1. Period, wavelength dependence]
The present inventors have verified by optical analysis whether light can be emitted in a specific direction as described above. The optical analysis was carried out by calculation using the Cybernet DiffractMOD. In these calculations, when light is vertically incident on the light emitting element from the outside, the increase or decrease in light absorption in the photoluminescence layer is calculated, thereby obtaining the enhancement of the light emitted vertically to the outside. The process in which light incident from the outside is coupled to the quasi-waveguide mode and absorbed by the photoluminescence layer is converted into propagating light that is emitted from the photoluminescence layer to the quasi-waveguide mode and exits perpendicularly to the outside. This corresponds to the calculation of the opposite process. Further, in the calculation of the electric field distribution in the pseudo waveguide mode, the electric field when light is incident from the outside was calculated in the same manner.

The film thickness of the photoluminescence layer is 1 μm, the refractive index of the photoluminescence layer is n _wav = 1.8, the height of the periodic structure is 50 nm, the refractive index of the periodic structure is 1.5, the emission wavelength and the period of the periodic structure are FIG. 2 shows the result of calculating the intensities of the light emitted in the front direction while changing each. As shown in FIG. 1A, the calculation model was calculated with a uniform one-dimensional periodic structure in the y direction, and the polarization of light was a TM mode having an electric field component parallel to the y direction. From the result of FIG. 2, it can be seen that a peak of enhancement exists at a certain combination of wavelength and period. In FIG. 2, the magnitude of the enhancement is represented by the shade of the color, and 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 rectangular as shown in FIG. 1B. A graph illustrating the conditions of m = 1 and m = 3 in equation (10) is shown in FIG. Comparing FIG. 2 and FIG. 3, it can be seen that the peak positions in FIG. 2 exist at locations corresponding to m = 1 and m = 3. The reason why m = 1 is stronger is that the diffraction efficiency of the first-order diffracted light is higher than that of the third-order or higher-order diffracted light. The reason why the peak of m = 2 does not exist is that the diffraction efficiency in the periodic structure is low.

  In the region corresponding to each of m = 1 and m = 3 shown in FIG. 3, it can be confirmed that there are a plurality of lines in FIG. This is considered to be because there are a plurality of pseudo waveguide modes.

[10-2. Thickness dependence]
In FIG. 4, the refractive index of the photoluminescence 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 photoluminescence layer are changed. It is a figure which shows the result of having calculated the intensification of the light output in a front direction. It can be seen that the light intensity reaches a peak when the thickness t of the photoluminescence 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 where the peak exists in FIG. 4 is 600 nm and the thickness is t = 238 nm and 539 nm. For comparison, FIG. 5C shows the result of the same calculation performed when t = 300 nm where no peak exists. The calculation model was assumed to be a one-dimensional periodic structure uniform in the y direction, as described above. 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. In the case of t = 238 nm and 539 nm, there is a high electric field intensity distribution, whereas in the case of t = 300 nm, the electric field intensity is low overall. This is because when t = 238 nm and 539 nm, a waveguide mode exists and light is strongly confined. Furthermore, there is always a convex portion or a portion (antinode) where the electric field is strongest immediately below the convex portion, and it can be seen that the electric field correlated with the periodic structure 120 is generated. That is, it can be seen that a guided mode is obtained according to the arrangement of the periodic structure 120. Further, comparing the case of t = 238 nm with the case of t = 539 nm, it can be seen that the mode is different in the number of nodes (white portions) in the z direction by one.

[10-3. Polarization dependence]
Next, in order to confirm the polarization dependence, the light enhancement was calculated for the case where the polarization of the light is a TE mode having an electric field component perpendicular to the y direction under the same conditions as those in FIG. The result of this calculation is shown in FIG. Compared to the TM mode (FIG. 2), the peak position is slightly changed, but the peak position is within the region shown in FIG. Therefore, it was confirmed that the configuration of this embodiment is effective for both TM mode and TE mode polarization.

[10-4. Two-dimensional periodic structure]
Furthermore, the effect by a two-dimensional periodic structure was examined. FIG. 7A is a plan view showing a part of a two-dimensional periodic structure 120 ′ in which concave and convex portions are arranged in both the x and y directions. The black area in the figure indicates a convex portion, and the white area indicates a concave portion. 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). It can be expected that different results will be obtained. FIG. 7B shows the result of calculating the light enhancement for such a two-dimensional periodic structure. The calculation conditions other than the periodic structure are the same as the conditions in FIG. As shown in FIG. 7B, in addition to the peak position in the TM mode shown in FIG. 2, a peak position that coincides with 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. In addition, regarding the two-dimensional periodic structure, it is necessary to consider diffraction that satisfies the first-order diffraction conditions simultaneously in both the x direction and the y direction. Such diffracted light is emitted in the direction of an angle corresponding to a period √2 times (that is, 2 ^1/2 times) the period p. Therefore, in addition to the peak in the case of the one-dimensional periodic structure, it is considered that a peak is generated for a period that is √2 times the period p. In FIG. 7B, such a peak can also be confirmed.

  The two-dimensional periodic structure is not limited to a square lattice structure having the same period in the x direction and the y direction as shown in FIG. 7A, but is a lattice structure in which hexagons and triangles are arranged as shown in FIGS. 18A and 18B. Also good. Moreover, the structure where the period of a direction differs (for example, x direction and y direction in the case of a square lattice) may be sufficient.

  As described above, in this embodiment, the characteristic pseudo-waveguide mode light formed by the periodic structure and the photoluminescence layer is selectively emitted only in the front direction using the diffraction phenomenon due to the periodic structure. I was able to confirm that it was possible. With such a configuration, light emission having directivity can be obtained by exciting the photoluminescence layer with excitation light such as ultraviolet rays or blue light.

[11. Study of periodic structure and photoluminescence layer configuration]
Next, the effect when various conditions such as the structure of the periodic structure and the photoluminescence layer and the refractive index are changed will be described.

[11-1. Refractive index of periodic structure]
First, the refractive index of the periodic structure was examined. The film thickness of the photoluminescence layer is 200 nm, the refractive index of the photoluminescence layer is n _wav = 1.8, the periodic structure is a uniform one-dimensional periodic structure in the y direction as shown in FIG. 1A, the height is 50 nm, and the period is The calculation was performed on the assumption that the light polarization was TM mode having an electric field component parallel to the y direction. FIG. 8 shows the result of calculating the enhancement 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 results when the film thickness of the photoluminescence layer is 1000 nm under the same conditions.

  First, focusing on the film thickness of the photoluminescence layer, the light intensity with respect to the change in the refractive index of the periodic structure is more peak when the film thickness is 1000 nm (FIG. 9) than when the film thickness is 200 nm (FIG. 8). It can be seen that the shift of the wavelength (referred to as the peak wavelength) becomes small. This is because the pseudo-waveguide mode is more susceptible to the refractive index of the periodic structure as the film thickness of the photoluminescence layer is smaller. That is, the higher the refractive index of the periodic structure, the higher the effective refractive index, and the corresponding peak wavelength shifts to the longer wavelength side. This effect becomes more pronounced as the film thickness decreases. 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, paying attention to 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, the higher the rate at which the light in the pseudo waveguide mode is emitted to the outside, so that the effect of confining the light decreases, that is, the Q value decreases. In order to keep the peak intensity high, a configuration in which light is appropriately emitted to the outside by using a pseudo-waveguide mode having a high light confinement effect (that is, a high Q value) may be used. In order to realize this, it is understood that it is not desirable to use a material having a refractive index that is too large compared to the refractive index of the photoluminescence 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 (that is, the translucent layer) constituting the periodic structure may be made equal to or less than the refractive index of the photoluminescence layer. The same applies when the photoluminescence layer contains a material other than the photoluminescence material.

[11-2. Periodic structure height]
Next, the height of the periodic structure was examined. The film thickness of the photoluminescence layer is 1000 nm, the refractive index of the photoluminescence layer is n _wav = 1.8, the periodic 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. Calculation was performed assuming that the period was 400 nm and the polarization of light was TM mode having an electric field component parallel to the y direction. FIG. 10 shows the result of calculating the enhancement 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 the Q value (that is, the line width of the peak) do not change at a height above a certain level, 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. This is because, when the refractive index n _{wav of the} photoluminescence layer is higher than the refractive index n _{p of the} periodic structure (FIG. 10), the light is totally reflected, so that the electric field bleeds out (evanescent) in the pseudo waveguide mode. Only due to the interaction with the periodic structure. When the height of the periodic structure is sufficiently large, the influence of the interaction between the evanescent part of the electric field and the periodic structure is constant 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), the light reaches the surface of the periodic structure without being totally reflected, so the height of the periodic structure The larger the is, the more affected. 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} photoluminescence 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. .

[11-3. Polarization direction]
Next, the polarization direction was examined. FIG. 12 shows the result of calculation assuming that the polarization of light is a TE mode having an electric field component perpendicular to the y direction under the same conditions as those shown in FIG. In the TE mode, the electric field of the quasi-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} photoluminescence layer, the peak intensity and the Q value are significantly decreased as compared with the TM mode.

[11-4. Refractive index of photoluminescence layer]
Next, the refractive index of the photoluminescence layer was examined. FIG. 13 shows the result when the refractive index n _wav of the photoluminescence layer is changed to 1.5 under the same conditions as the calculation shown in FIG. It can be seen that the same effect as in FIG. 9 is obtained even when the refractive index n _{wav of the} photoluminescence layer is 1.5. 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 λ ₀ <n _wav × p / m = 1.5 × 400 nm / 1 = 600 nm from Equation (10).

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

[12. Modified example]
Hereinafter, modifications of the present embodiment will be described.

[12-1. Configuration with substrate]
As described above, the light-emitting element may have a structure in which the photoluminescence layer 110 and the periodic structure 120 are formed on the transparent substrate 140 as illustrated in FIGS. 1C and 1D. In order to manufacture such a light-emitting element 100a, first, a thin film is formed on a transparent substrate 140 with a photoluminescent material (including a matrix material, if necessary, the same applies below) constituting the photoluminescent layer 110, A method of forming the periodic structure 120 thereon can be considered. In such a configuration, in order for the photoluminescence layer 110 and the periodic structure 120 to have a function of emitting light in a specific direction, the refractive index n _s of the transparent substrate 140 is less than the refractive index n _{wav of the} photoluminescence layer. It is necessary to. When the transparent substrate 140 is provided so as to be in contact with the photoluminescence layer 110, it is necessary to set the period p so as to satisfy the equation (15) where the refractive index n _out of the emission medium in the equation (10) is n _s. .

In order to confirm this, a calculation was performed when the photoluminescence layer 110 and the periodic structure 120 having the same conditions as the calculation shown in FIG. 2 were provided on the transparent substrate 140 having a refractive index of 1.5. The result of this calculation is shown in FIG. As in the result of FIG. 2, it can be confirmed that a peak of light intensity appears in a specific period for each wavelength, but it can be seen that the range of the period in which the peak appears is different from the result of FIG. In contrast, shows the condition of the expression condition of (10) was n _out = n _s equation (15) in FIG. 15. In FIG. 14, it can be seen that the peak of the light intensity appears in the region corresponding to the range shown in FIG.

  Therefore, in the light emitting element 100a in which the photoluminescence layer 110 and the periodic structure 120 are provided on the transparent substrate 140, an effect is obtained in the range of the period p that satisfies the expression (15), and the period p that satisfies the expression (13). In particular, a remarkable effect can be obtained in this range.

[12-2. Light emitting device having excitation light source]
FIG. 16 is a diagram illustrating a configuration example of a light-emitting device 200 including the light-emitting element 100 illustrated in FIGS. 1A and 1B and a light source 180 that causes excitation light to enter the photoluminescence layer 110. As described above, in the configuration of the present disclosure, light emission having directivity can be 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 thereto, and is appropriately determined according to the photoluminescent material constituting the photoluminescent layer 110. 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. However, the present invention is not limited to such an example. 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 (ie, obliquely) with respect to a direction perpendicular to the main surface (ie, upper surface or lower surface) of the photoluminescence layer 110. By making the excitation light incident obliquely at an angle at which total reflection occurs in the photoluminescence layer 110, light can be emitted more efficiently.

There is also a method for efficiently emitting light by coupling excitation light into a pseudo-guide mode. 17A to 17D are diagrams for explaining such a method. In this example, the photoluminescence layer 110 and the periodic structure 120 are formed on the transparent substrate 140 as in the configuration shown in FIGS. 1C and 1D. First, as shown in FIG. 17A, the period p _x in the x direction is determined for light emission enhancement, and then, the period in the y direction is used to couple the excitation light to the pseudo waveguide mode as shown in FIG. 17B. to determine the p _y. The period p _x is determined so as to satisfy the condition in which p is replaced with p _x in Equation (10). On the other hand, in the period _py , m is an integer equal to or larger than 1, the wavelength of the excitation light is λ _ex , and the medium having the highest refractive index excluding the periodic structure 120 out of the medium in contact with the photoluminescence layer 110 is n _out. The following equation (16) is satisfied.

Here, n _out is n _s of the transparent substrate 140 in the example of FIG. 17B, but in the configuration in which the transparent substrate 140 is not provided as in FIG. 16, it is the refractive index of air (about 1.0).

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.

Thus, by setting the cycle 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 having 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 structure shown in FIG. 17A and FIG. 17B, respectively. In this calculation, p _x = 365 nm and 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. It is said. As shown in FIG. 17D, not only the light generated from the photoluminescence layer 110 but also light having a wavelength of about 450 nm that is excitation light is shown. This is because the incident light is effectively converted into the pseudo-waveguide mode, so that the proportion absorbed by the photoluminescence layer can be increased. In addition, the absorptance is increased with respect to the emission wavelength of about 600 nm. This is because if the light having a wavelength of about 600 nm is incident on this structure, the pseudo-waveguide mode can be effectively effectively applied. Is converted to. As described above, the periodic structure 120 illustrated in FIG. 17B is a two-dimensional periodic structure having structures with different periods (referred to as periodic components) in each of the x direction and the y direction. Thus, by using a two-dimensional periodic structure having a plurality of periodic components, it is possible to increase the emission intensity while increasing the excitation efficiency. In FIGS. 17A and 17B, the excitation light is incident from the substrate 140 side, but the same effect can be obtained even if it is incident from the periodic 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 as shown in FIG. 18B are periodically arranged. By arranging them in a line, a plurality of main axes (in the example of the figure, axes 1 to 3) that can be regarded as periods can be determined. For this reason, a different period can be assigned to each axial direction. Each of these periods may be set to increase the directivity of light having 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).

[12-3. Periodic structure on transparent substrate]
As shown in FIGS. 19A and 19B, the periodic 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 periodic structure 120 a made of unevenness on the substrate 140. As a result, a periodic 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 processed to be flat. Also in these configuration examples, directional light emission can be realized by setting the period p of the periodic structure 120a so as to satisfy Expression (15).

In order to verify this effect, in the configuration of FIG. 19A, the intensity of light output in the front direction was calculated by changing the emission wavelength and the period of the periodic structure. Here, the film thickness of the photoluminescence layer 110 is 1000 nm, the refractive index of the photoluminescence layer 110 is n _wav = 1.8, the periodic structure 120a is a uniform one-dimensional periodic structure in the y direction, the height is 50 nm, and the refractive index is It was assumed that n _p = 1.5, the period was 400 nm, and the polarization of light was a 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, a peak of light intensity was observed at a period satisfying the condition of Expression (15).

[12-4. powder]
According to the above embodiment, light emission of an arbitrary wavelength can be emphasized by adjusting the period of the periodic structure and the film thickness of the photoluminescence layer. For example, if a photoluminescent material that emits light in a wide band is used as shown in FIGS. 1A and 1B, only light of a certain wavelength can be emphasized. Therefore, the structure of the light emitting element 100 as shown in FIGS. 1A and 1B may be powdered and used as a fluorescent material. 1A and 1B may be used by being embedded in a resin or glass.

  1A and 1B, since only a specific wavelength can be emitted in a specific direction, it is difficult to realize light emission such as white having a spectrum in a wide wavelength range. Therefore, as shown in FIG. 20, by using a mixture of a plurality of powdered light emitting elements 100 having different conditions such as the period of the periodic structure and the film thickness of the photoluminescence layer, a light emitting device having a spectrum in a wide wavelength range 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.

[12-5. 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 photoluminescence layer. In this example, three types of periodic structures 120a, 120b, and 120c are arranged without a gap. For example, the periodic structures 120a, 120b, and 120c have a period set so as to emit light in the red, green, and blue wavelength ranges to the front. Thus, directivity can be exhibited with respect to a spectrum in a wide wavelength region by arranging a plurality of structures with different periods on the photoluminescence layer. The configuration of the plurality of periodic structures is not limited to the above, and may be set arbitrarily.

[12-6. Laminated structure]
FIG. 22 illustrates an example of a light-emitting element having a structure in which a plurality of photoluminescence layers 110 having an uneven structure formed on the surface are stacked. A transparent substrate 140 is provided between the plurality of photoluminescence layers 110, and the concavo-convex structure formed on the surface of the photoluminescence layer 110 of each layer corresponds to the periodic structure or the submicron structure. In the example shown in FIG. 22, the three-layer periodic structures having different periods are formed, and the periods are set so as to emit light in the red, blue, and green wavelength ranges to the front. 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. In this way, directivity can be exhibited with respect to a spectrum in a wide wavelength range by laminating a plurality of periodic structures having different periods.

  Note that the number of layers, the structure of the photoluminescence layer 110 of each layer, and the periodic structure are not limited to those described above, and may be arbitrarily set. For example, in the structure of two layers, the first photoluminescence layer and the second photoluminescence layer are formed so as to face each other through the light-transmitting substrate, and the surface of the first and second photoluminescence layers is formed on the surface. The first and second periodic structures will be formed respectively. In this case, for each of the first photoluminescence layer and the first periodic structure pair and the second photoluminescence layer and the second periodic structure pair, the condition corresponding to the equation (15) may be satisfied. That's fine. Similarly, in the configuration of three or more layers, the condition corresponding to the formula (15) may be satisfied for the photoluminescence layer and the periodic structure in each layer. The positional relationship between the photoluminescence layer and the periodic structure may be reversed from that shown in FIG. In the example shown in FIG. 22, the period of each layer is different, but they may all be the same period. In that case, the spectrum cannot be widened, but the emission intensity can be increased.

[12-7. Configuration with protective layer]
FIG. 23 is a cross-sectional view illustrating a configuration example in which a protective layer 150 is provided between the photoluminescence layer 110 and the periodic structure 120. As described above, the protective layer 150 for protecting the photoluminescence layer 110 may be provided. However, when the refractive index of the protective layer 150 is lower than the refractive index of the photoluminescence layer 110, an electric field of light oozes out only about half the wavelength inside the protective layer 150. Therefore, when the protective layer 150 is thicker than the wavelength, light does not reach the periodic structure 120. For this reason, there is no pseudo waveguide mode, and a function of emitting light in a specific direction cannot be obtained. When the refractive index of the protective layer 150 is about the same as or higher than the refractive index of the photoluminescence 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 that 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”) from a photoluminescent material. Therefore, it is desirable that the protective layer 150 is thin even in this case. Note that the protective layer 150 may be formed using the same material as the periodic structure (translucent layer) 120. At this time, the light-transmitting layer having a periodic structure also serves as a protective layer. The refractive index of the light transmitting layer 120 is preferably smaller than that of the photoluminescent layer 110.

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

As the material of the periodic structure, for example, a dielectric having low light absorption can be used. Examples of the material of the periodic structure include, 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 periodic structure is made lower than the refractive index of the photoluminescence layer, MgF ₂ , LiF, CaF ₂ , SiO ₂ , glass, resin having a refractive index of about 1.3 to 1.5. Can be used.

The photoluminescent material includes a fluorescent material and a phosphorescent material in a narrow sense, includes not only an inorganic material but also an organic material (for example, a dye), and further includes a quantum dot (that is, a semiconductor fine particle). In general, a fluorescent material having an inorganic material as a host tends to have a high refractive index. Examples of fluorescent materials that emit 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 fluorescent materials that emit green light include M ₂ MgSi ₂ O ₇ : Eu ²⁺ (M = at least one selected from Ba, 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⁺ (at least one selected from M = 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 emitting red light include CaAlSiN ₃ : Eu ²⁺ , SrAlSi ₄ O ₇ : Eu ²⁺ , M ₂ Si ₅ N ₈ : Eu ²⁺ (at least one selected from M = Ba, Sr and Ca). Species), 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⁺ (M = SiO, at least one selected from Ba, Sr and Ca), M ₃ SiO ₅ : Eu ²⁺ (M = at least one selected from Ba, Sr and Ca) can be used. Examples of fluorescent materials that emit 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, for example, materials such as CdS, CdSe, core / shell 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 transparent substrate 140 shown in FIGS. 1C, 1D, and the like is made of a light-transmitting 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. Note that it is not essential for the substrate 140 to be transparent in a configuration in which excitation light is incident on the photoluminescence layer 110 without passing through the substrate 140. The substrate 140 may be, 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 , La
SrAlO ₄ , LaSrGaO ₄ , LaTaO ₃ , SrO, YSZ (ZrO ₂ .Y ₂ O ₃ ), YAG, or Tb ₃ Ga ₅ O ₁₂ may be used.

[14. Production method]
Then, an example of the manufacturing method of a light emitting element is demonstrated.

  As a method of realizing the configuration shown in FIGS. 1C and 1D, for example, a thin film of the photoluminescence layer 110 is formed on the transparent substrate 140 by a process such as vapor deposition, sputtering, and coating, and then a dielectric is formed. There is a method of forming the periodic structure 120 by patterning by a method such as photolithography. Instead of the above method, the periodic structure 120 may be formed by nanoimprinting. Further, as shown in FIG. 24, the periodic structure 120 may be formed by processing only a part of the photoluminescence layer 110. In that case, the periodic structure 120 is formed of the same material as the photoluminescence layer 110.

  The light-emitting element 100 illustrated in FIGS. 1A and 1B can be realized by, for example, manufacturing the light-emitting element 100a illustrated in FIGS. 1C and 1D and then performing a process of removing the portions of the photoluminescence layer 110 and the periodic structure 120 from the substrate 140. is there.

  In the configuration shown in FIG. 19A, for example, after the periodic structure 120a is formed on the transparent substrate 140 by a method such as a semiconductor process or nanoimprint, the material constituting the photoluminescence layer 110 is formed thereon by a method such as vapor deposition or sputtering. This is possible by doing. Alternatively, the structure shown in FIG. 19B can be realized by embedding the concave portion of the periodic structure 120a with the photoluminescence layer 110 using a method such as coating.

  In addition, said manufacturing method is an example and the manufacturing method of the directional light emitting element of this indication is not limited above.

[15. Experimental example]
Hereinafter, an example in which a directional light emitting element that can be applied to the embodiment of the present disclosure is manufactured will be described.

  A sample of a light-emitting element having the same structure as that in FIG. 19A was prototyped, and the characteristics were evaluated. The light emitting element was manufactured as follows.

  A glass substrate was provided with a one-dimensional periodic structure (stripe-shaped convex portion) having a period of 400 nm and a height of 40 nm, and YAG: Ce, which is a photoluminescence material, was formed to a thickness of 210 nm thereon. 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 is emitted by exciting it with a 450 nm LED. FIG. 26 shows measurement results (ref) in the absence of a periodic structure, results of measuring a TM mode having a polarization component parallel to the one-dimensional periodic structure, and a TE mode having a perpendicular polarization component. . In the case where there is a periodic structure, it can be seen that the light of a specific wavelength is remarkably increased compared to the case where there is no periodic structure. It can also be seen that the TM mode having a polarization component parallel to the one-dimensional periodic structure has a larger light enhancement effect.

  Furthermore, in the same sample, the results of measuring the angle dependency of the emitted light intensity and the calculation results are shown in FIGS. 27A to 27F and FIGS. 28A to 28F. FIG. 27A shows a state 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 results and calculation results for the case of rotating in this way. 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. FIG. 27E and FIG. 27F show the measurement result and the calculation result in this case, respectively. FIG. 28A shows a state 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. FIG. 28B and FIG. 28C show measurement results and calculation results in this case, respectively. On the other hand, FIG. 28D shows a situation where the light emitting element that emits TM mode linearly polarized light is rotated about the axis perpendicular to the line direction of the one-dimensional periodic structure 120 as the rotation axis. FIG. 28E and FIG. 28F show the measurement result and the calculation result in this case, respectively.

  As is clear from FIGS. 27A to 27F and FIGS. 28A to 28F, the TM mode has a higher effect of enhancement. It can also be seen that the wavelength of the enhanced light shifts with angle. For example, it can be seen that light having a wavelength of 610 nm has a high directivity and emits polarized light because the light exists only in the TM mode and in the front direction. 27B and 27C, FIG. 27E and FIG. 27F, FIG. 28B and FIG. 28C, and FIG. 28E and FIG. Supported by.

  FIG. 29 shows the angle dependence of the intensity when light having a wavelength of 610 nm is rotated about a direction perpendicular to the line direction as the rotation axis, as shown in FIG. 28D. There is a strong light emission enhancement in the front direction, and it can be seen that the light is hardly enhanced at other angles. 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 respect to the direction of the maximum intensity. From the results shown in FIG. 29, it can be seen that directional light emission is realized. Furthermore, since all the emitted light is a TM mode component, it can be seen that polarized light emission is realized at the same time.

  The verification experiment described above was performed using YAG: Ce that emits light in a wide wavelength band. Even if an experiment is performed with a similar configuration using a photoluminescent material that emits light in a narrow band, high directivity and polarized light emission can be realized for light of that wavelength. Further, when such a photoluminescent material is used, a light source that does not generate light in other directions and in other polarization states can be realized because light of other wavelengths is not generated.

[16. Other variations]
As described above, the wavelength and emission direction of light subjected to the light emission enhancement effect by the submicron structure of the light emitting element of the present disclosure depend on the configuration of the submicron structure. Consider a light-emitting element having a periodic structure 120 on a photoluminescence layer 110 shown in FIG. Here, the periodic structure 120 is formed of the same material as that of the photoluminescence layer 110, and the case where the periodic structure 120 includes the one-dimensional periodic structure 120 illustrated in FIG. 1A is illustrated. The light receiving the emission enhancement by the one-dimensional periodic structure 120 is defined as a period p (nm) of the one-dimensional periodic structure 120, a refractive index n _wav of the photoluminescence layer 110, and a refractive index n _out of an external medium from which the light is emitted, When the incident angle to the one-dimensional periodic structure 120 is θ _wav and the exit angle from the one-dimensional periodic structure 120 to the external medium is θ _out , p × n _wav × sin θ _wav −p × n _out × sin θ _out = mλ The relationship is satisfied (see the above formula (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, in general, 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 the visible light differs depending on the direction of observation.

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 the material has wavelength dispersion (wavelength dependence), the wavelength of n _wav and n _out 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 a material for forming the photoluminescence layer 110 and the one-dimensional periodic structure 120, a material having a small wavelength dispersion of the refractive index n _wav is used. It is desirable to select. Furthermore, a reverse dispersion material is preferable in which the refractive index is low for light having a shorter refractive index n _wav .

  Also, as shown in FIG. 32A, white light can be emitted by arranging a plurality of periodic structures having different wavelengths that exhibit a light emission enhancement effect. In the example shown in FIG. 32A, a periodic structure 120r that can enhance red light (R), a periodic structure 120g that can enhance green light (G), and a periodic structure 120b that can enhance blue light (B) are arranged in a matrix. Has been. The periodic structures 120r, 120g, and 120b are, for example, one-dimensional periodic structures, and the convex portions are arranged in parallel to each other. Therefore, the polarization characteristics are the same for all colors of red, green, and blue. By the periodic structures 120r, 120g, and 120b, the light of the three primary colors that has received light emission enhancement is emitted and mixed, resulting in white light and linearly polarized light.

  When the periodic structures 120r, 120g, and 120b arranged in a matrix are called unit periodic structures (or pixels), the size of the unit periodic structure (that is, the length of one side) is, for example, three times or more of the period. is there. In order to obtain a mixed color effect, it is desirable that the unit periodic structure is not recognized by the human eye. For example, the length of one side is preferably smaller than 1 mm. Here, although each unit periodic structure is drawn in the square, it is not restricted to this, For example, the periodic structures 120r, 120g, and 120b which adjoin each other may be shapes other than squares, such as a rectangle, a triangle, and a hexagon.

  In addition, the photoluminescence layer provided under the periodic structures 120r, 120g, and 120b may be common to the periodic structures 120r, 120g, and 120b, or different photoluminescence materials corresponding to light of the respective colors. A photoluminescence layer may be provided.

  As shown in FIG. 32B, a plurality of periodic structures (including periodic structures 120h, 120i, and 120j) having different orientations in which the convex portions of the one-dimensional periodic structure extend may be arranged. The wavelengths of light with which a plurality of periodic structures enhance light emission 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. Further, when the arrangement of FIG. 32B is applied to each of the periodic structures 120r, 120g, and 120b in FIG. 32A, unpolarized white light can be obtained as a whole.

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

  As shown in FIG. 33, for example, an array of microlenses 130 may be arranged on the light emission side of the light emitting element. By using the array of microlenses 130 to bend light emitted in an oblique direction in the normal direction, a color mixing effect can be obtained.

  The light-emitting element shown in FIG. 33 has regions R1, R2, and R3 having the periodic structures 120r, 120g, and 120b in FIG. 32A, respectively. In the region R1, the red light R is emitted in the normal direction by the periodic structure 120r, for example, the green light G is emitted in an oblique direction. The green light G emitted in the oblique direction is bent in the normal direction by the refraction action of the microlens 130. As a result, in the normal direction, the red light R and the green light G are mixed and observed. Thus, by providing the microlens 130, the phenomenon that the wavelength of the emitted light differs 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, and can also be applied to the configuration shown in FIG. 32B or 32C.

  The optical element having an action of bending light emitted in an oblique direction may be a lenticular lens instead of the microlens array. In addition to a lens, a prism can also be used. An array of prisms may be used. You may arrange | position a prism separately 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.

  A method for obtaining white light (or light having a wide spectral width) is not only based on the above-described periodic structure but also based on a photoluminescence layer as shown in FIGS. 34A and 34B, for example. As shown in FIG. 34A, white light can be obtained by stacking a plurality of photoluminescence layers 110b, 110g, and 110r having different emission wavelengths. The stacking order is not limited to the illustrated example. As shown in FIG. 34B, a photoluminescence layer 110y that emits yellow light may be stacked on the photoluminescence layer 110b that emits blue light. The photoluminescence layer 110y can be formed using, for example, YAG.

  In addition, when using a photoluminescent material that is 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. White light can be emitted. Such a photoluminescence layer capable of emitting white light can be used in the configuration in which the unit periodic structure is tiled as described with reference to FIGS. 32A to 32C.

  The illumination device of the present disclosure can be used as illumination that can present information as an image.

100, 100a, 100W, 530a, 630a Light emitting element 100w, 630w White light emitting portion 500A, 500B Illuminating device 500S, 510S, 520S Illuminating system 510, 520 Projecting device 511, 521, 521A, 522, 601 Light source unit 512, 522 Light source 512e 522e, 602e Excitation light source 515, 525, 605 Optical fiber 516, 526, 606 Light distribution control unit 800 Housing 810 Competition facility

Claims (21)

A first light source unit configured to generate white light, and emitting the white light; thereby, a first region, a second region in the first region, and a second region having relatively low illuminance; A first projection device forming
A second light source unit for generating a plurality of different color lights, and at least one first light distribution control element disposed at a position where at least one of the plurality of different color lights is incident, By irradiating at least a part of the second area with the light of the plurality of different colors whose traveling direction and / or intensity is changed by at least one first light distribution control element, an image is formed on the second area. A second projection device for displaying the illumination device.   The lighting device according to claim 1, wherein the color rendering property of the white light is higher than the color rendering property of the white light obtained by combining the light of the plurality of different colors. A first light source unit configured to generate white light, and emitting the white light; thereby, a first region, a second region in the first region, and a second region having relatively low illuminance; A first projection device forming
A second light source unit that generates color light; and a first light distribution control element disposed at a position where the color light is incident. At least one of a traveling direction and intensity is changed by the first light distribution control element. And a second projection device that displays an image on the second region by irradiating at least a part of the second region with the colored light.   The first projection device further includes a second light distribution control element disposed at a position where the white light is incident, and the white light whose traveling direction and intensity are changed by the second light distribution control element is provided. The lighting device according to claim 1, wherein the first region and the second region are formed by emitting light.   At least one of the first light distribution control element and the second light distribution control element is a light modulation element that modulates the intensity of the incident light by reflecting or transmitting at least part of the incident light. Item 5. The lighting device according to Item 4. The first light source unit is
A first excitation light source;
A first photoluminescence light emitting element that emits the white light in response to the first excitation light from the first excitation light source,
The second light source unit is
A second excitation light source;
A second photoluminescent light emitting element that includes a plurality of photoluminescent portions each receiving a second excitation light from the second excitation light source and emitting one of the plurality of different colored lights. Item 6. The lighting device according to Item 4 or 5. A first optical fiber disposed between the first photoluminescence light emitting element and the second light distribution control element, wherein the second light distribution control is performed by the white light taken in from one end and emitted from the other end. A first optical fiber for illuminating the element; and
At least one second optical fiber disposed between the second photoluminescence light emitting element and the at least one first light distribution control element, wherein the plurality of different optical fibers are taken in from one end and emitted from the other end. The lighting device according to claim 6, comprising at least one of at least one second optical fiber that irradiates the first light distribution control element with at least one of colored light. A first optical fiber disposed between the first excitation light source and the first photoluminescence light-emitting element, the first photoluminescence emission by the first excitation light taken in from one end and emitted from the other end; A first optical fiber for illuminating the element; and
A second optical fiber disposed between the second excitation light source and the second photoluminescence light emitting element, the second photoluminescence emission by the second excitation light taken in from one end and emitted from the other end; The lighting device according to claim 6, comprising at least one of the second optical fibers that irradiates the element. The second photoluminescence light emitting element is:
A photoluminescence layer that receives the second excitation light and emits light having _a wavelength of λ _{a in} the air;
A translucent layer disposed proximate to the photoluminescence layer;
A surface structure formed on at least one surface of the photoluminescence layer and the translucent layer and including at least one of a plurality of convex portions and a plurality of concave portions, and
The lighting device according to claim 6, wherein the surface structure limits a directivity angle of the light having _a wavelength λ _{a in} the air emitted from the photoluminescence layer. A light source unit that independently emits white light and light of different colors;
A light distribution control element disposed at a position where the white light and the plurality of light of different colors are incident,
By emitting the white light whose at least one of the traveling direction and intensity is changed by the light distribution control element, the first region and the second region in the first region have relatively low illuminance. The second region is formed, and the plurality of different colors of light whose at least one of the traveling direction and intensity is changed by the light distribution control element are emitted to display an image on the second region. , Lighting equipment.   The lighting device according to claim 10, wherein the color rendering property of the white light is higher than the color rendering property of white light obtained by combining the light of the plurality of different colors.   The lighting device according to claim 10 or 11, wherein the light distribution control element is a light modulation element that modulates the intensity of the incident light by reflecting or transmitting at least part of the incident light. The light source unit is
An excitation light source;
A photoluminescence light emitting element that emits light in response to excitation light from the excitation light source,
The photoluminescence light emitting element is
A first photoluminescence portion that emits the white light in response to the excitation light;
The lighting device according to claim 10, further comprising: a second photoluminescence portion that receives the excitation light and emits one of the plurality of different colors of light.   An optical fiber disposed between the photoluminescence light emitting element and the light distribution control element, wherein the light distribution control is performed by the white light and the plurality of different color lights which are taken in from one end and emitted from the other end. The illuminating device of Claim 13 which has an optical fiber which irradiates an element.   An optical fiber disposed between the excitation light source and the photoluminescence light-emitting element, the optical fiber being irradiated from the one end and irradiating the photoluminescence light-emitting element with the excitation light emitted from the other end. The lighting device according to 13 or 14. The second photoluminescence portion of the photoluminescence light emitting element is:
A photoluminescence layer that emits light having _a wavelength of λ _{a in} the air in response to the excitation light;
A translucent layer disposed proximate to the photoluminescence layer;
A surface structure formed on at least one surface of the photoluminescence layer and the translucent layer and including at least one of a plurality of convex portions and a plurality of concave portions, and
The lighting device according to claim 13, wherein the surface structure limits a directivity angle of the light having _a wavelength λ _{a in} the air emitted from the photoluminescence layer. An illumination system including a first illumination device and a second illumination device,
Each of the first lighting device and the second lighting device is the lighting device according to any one of claims 1 to 16,
At least one of the first region or the second region in the first lighting device has an overlap with at least one of the first region or the second region in the second lighting device. Floor surface,
The ceiling,
One or more wall surfaces connecting the floor surface and the ceiling;
An illumination system including a plurality of light emitting portions provided on at least one of the floor surface, the ceiling, and the wall surface; and
The lighting system includes:
A light source unit that independently emits white light and light of different colors;
A light modulation element disposed inside each of the plurality of light emitting portions;
A plurality of optical fibers disposed between the plurality of light emitting units and the light source unit, wherein the plurality of optical fibers transmit the white light and the plurality of different color lights to each of the plurality of light emitting units. And having
Each of the light modulation elements modulates the white light and the plurality of different colors emitted from the corresponding optical fiber among the plurality of optical fibers,
Each of the plurality of light emitting units emits the modulated white light, thereby generating a first region, a second region in the first region, and a second region having a relatively low illuminance. And displaying an image on the second region by emitting the modulated light of different colors.   The facility according to claim 18, wherein the color rendering property of the white light is higher than the color rendering property of the white light obtained by combining the light of the plurality of different colors. A competition facility with a field where the competition takes place,
The field;
A spectator seat surrounding at least a part of the periphery of the field;
An illumination system including a plurality of illumination units disposed above the audience seat;
One or more pillars supporting the plurality of lighting units;
The lighting system includes:
A light source unit that independently emits white light and light of different colors;
A light modulation element disposed inside each of the plurality of lighting units;
A plurality of optical fibers disposed between the plurality of illumination units and the light source unit, the plurality of optical fibers transmitting the white light and the plurality of different color lights to each of the plurality of illumination units; Have
Each of the light modulation elements modulates the white light and the plurality of different colors emitted from the corresponding optical fiber among the plurality of optical fibers,
Each of the plurality of illumination units emits the modulated white light, thereby providing a first region and a second region in the first region that has a relatively low illuminance. A competition facility that displays an image on the second region by emitting the plurality of different colors of light that are formed and modulated in at least a part of the field.   The competition facility according to claim 20, wherein the color rendering property of the white light is higher than the color rendering property of the white light obtained by combining the light of the plurality of different colors.

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