Light source device and projector

Abstract

To provide an optical device that can prevent destruction of material of an antenna due to generation of heat from a phosphor.SOLUTION: A light source device of the present invention comprises: a light source that emits excitation light; a phosphor 34 on which the excitation light is incident and emits fluorescent light having a wavelength different from the wavelength of the excitation light; a first nano-antenna group 111 that is provided on the phosphor and has a plurality of first nano-antennas 112; and a second nano-antenna group 121 that is provided on the phosphor and has a plurality of second nano-antennas 122. The plurality of first nano-antennas are each formed of first metal. The plurality of second nano-antennas are each formed of second material having a higher melting point than the melting point of the first metal. In plan view seen from a normal direction of the phosphor, an irradiation area of the excitation light BAR overlaps an arrangement area of the second nano-antenna group NAR. The fluorescent light is electric-field enhanced by the plurality of first nano-antennas and the plurality of second nano-antennas.SELECTED DRAWING: Figure 8

Description

[Technical field]

[0001] The present invention relates to a light source device and a projector. [Background technology]

[0002] In recent years, solid-state light sources such as lasers, which have excellent characteristics such as mercury-free, high brightness, and long life, have been used as light sources for projectors, replacing the conventional mainstream mercury lamp light sources. For example, Patent Document 1 discloses an optical device having a wavelength converter and an antenna array. The wavelength converter has an entrance surface and an exit surface, converts the wavelength of incident light from the entrance surface to generate wavelength-converted light, and emits the wavelength-converted light from the exit surface. The antenna array is formed on the wavelength converter and has a plurality of antennas arranged at a period about the optical wavelength of the wavelength-converted light in the wavelength converter. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2018-013688 A Summary of the Invention [Problem to be solved by the invention]

[0004] Each of the antennas of the optical device disclosed in Patent Document 1 is made of a material having plasma in the visible wavelength range, such as gold (Au), or an alloy or laminate containing these materials. However, when the wavelength-converted light is emitted, the phosphor plate of the wavelength converter (wavelength conversion device) generates heat, causing problems such as melting or destruction of the antenna material. If the antenna material melts or is destroyed, the wavelength-converted light will be emitted in a direction different from the direction in which it should originally be emitted, and there is a risk of performance degradation of the light source device and the display device. [Means for solving the problem]

[0005] In order to solve the above problems, an optical device according to one embodiment of the present invention includes a light source that emits excitation light, a phosphor that receives the excitation light and emits fluorescence having a wavelength different from that of the excitation light, a first nanoantenna group provided on the phosphor and having a plurality of first nanoantennas, and a second nanoantenna group provided on the phosphor and having a plurality of second nanoantennas. Each of the first nanoantennas is made of a metal. Each of the second nanoantennas is made of a material having a melting point higher than that of the metal. In a plan view seen from the normal direction of the phosphor, the irradiation area of ​​the excitation light overlaps with the arrangement area of ​​the second nanoantenna group. The fluorescence is electric field enhanced by each of the first nanoantennas and each of the second nanoantennas. [Brief description of the drawings]

[0006] [Figure 1] FIG. 1 is a schematic configuration diagram of a projector according to a first embodiment. [Diagram 2] 2 is a schematic configuration diagram of an illumination device provided in the projector of FIG. 1. [Diagram 3] FIG. 1 is a plan view of a typical fluorescent light emission section. [Figure 4] 4 is a cross-sectional view of the fluorescence emission part shown in FIG. 3 taken along line C1-C1. [Diagram 5] FIG. 11 is a cross-sectional view for explaining surface lattice resonance occurring in a general group of nanoantennas. [Figure 6] FIG. 13 is a diagram showing a simulation result of the radiation angle distribution of fluorescence emitted from a general phosphor. [Figure 7] 4 is a diagram showing a simulation result of the radiation angle distribution of fluorescence emitted from a phosphor of the fluorescence emitting portion shown in FIG. 3. [Figure 8] FIG. 2 is a plan view of the fluorescence emission part of the first embodiment. [Figure 9] 9 is a cross-sectional view of the fluorescence emission part shown in FIG. 8 taken along line C2-C2. [Figure 10] FIG. 11 is a cross-sectional view of a fluorescence emission part of the second embodiment. [Figure 11] FIG. 11 is a cross-sectional view of a fluorescence emission part of the third embodiment. [Figure 12] FIG. 13 is a diagram showing a simulation result of the change in the reflection spectrum when the maximum width of the first nanoantenna of the fluorescence emitting portion is 200 nm. [Figure 13] FIG. 13 is a diagram showing a simulation result of the change in the reflection spectrum when the maximum width of the first nanoantenna of the fluorescence emitting portion is 250 nm. [Figure 14] FIG. 13 is a diagram showing a simulation result of the change in the reflection spectrum when the maximum width of the first nanoantenna of the fluorescence emitting portion is 300 nm. [Figure 15] FIG. 13 is a cross-sectional view of a fluorescence emission part of the fourth embodiment. [Figure 16] FIG. 13 is a cross-sectional view of a fluorescence emission part of the fifth embodiment. [Figure 17] FIG. 13 is a cross-sectional view of a fluorescence emission part of the sixth embodiment. [Figure 18] FIG. 13 is a schematic configuration diagram of an illumination device provided in a projector according to a seventh embodiment. [Figure 19] FIG. 23 is a cross-sectional view of a fluorescence emission part of the seventh embodiment. [Figure 20] FIG. 23 is a cross-sectional view of a fluorescence emission part of the eighth embodiment. [Figure 21] FIG. 13 is a cross-sectional view of a fluorescence emission part of the ninth embodiment. [Figure 22] FIG. 23 is a cross-sectional view of a fluorescence emission part of the tenth embodiment. [Diagram 23] FIG. 23 is a cross-sectional view of a fluorescent light emission part of the eleventh embodiment. [Figure 24] FIG. 23 is a cross-sectional view of a fluorescence emission part of a twelfth embodiment. [Diagram 25] FIG. 23 is a cross-sectional view of the fluorescence emission part of the thirteenth embodiment. [Figure 26] FIG. 23 is a cross-sectional view of the fluorescence emission part of the fourteenth embodiment. [Figure 27] FIG. 23 is a schematic configuration diagram of an illumination device provided in a projector according to a fifteenth embodiment. [Figure 28] 28 is a plan view of the phosphor wheel of the lighting device shown in FIG. 27 as viewed in a direction along the optical axis AX2. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0007] [First embodiment] A first embodiment of the present invention will be described below with reference to FIGS. Fig. 1 is a schematic configuration diagram showing a projector 1 according to a first embodiment. Fig. 2 is a side view of an illumination device 2 provided in the projector 1. In the drawings, the dimensions of some components may be reduced to different scales in order to make the components easier to see.

[0008] The projector of this embodiment is an example of a projector that uses three transmissive liquid crystal light valves as light modulation devices. For example, a reflective liquid crystal light valve may be used as the light modulation device. As the light modulation device, a light modulation device other than liquid crystal, such as a device using a micromirror or a device equipped with a DMD (Digital Micromirror Device), may be used.

[0009] (projector) First, the configuration of the projector 1 will be described. As shown in FIG. 1, the projector 1 includes an illumination device 2, a color separation optical system 3, a light modulation device 4R, a light modulation device 4G, and a light modulation device 4B, a light synthesis optical system 5, and a projection optical system 6. The projector 1 includes optical devices described below. The illumination device 2 emits illumination light WL. The color separation optical system 3 separates the illumination light WL emitted from the illumination device 2 into red light LR, green light LG, and blue light LB. The light modulation device 4R, the light modulation device 4G, and the light modulation device 4B modulate the red light LR, the green light LG, and the blue light LB according to image information, respectively, to form image light of each color. The light synthesis optical system 5 synthesizes the image light of each color emitted from the light modulation device 4R, the light modulation device 4G, and the light modulation device 4B. The projection optical system 6 projects the image light synthesized by the light synthesis optical system 5 toward a screen SCR.

[0010] 2, the lighting device 2 emits white illumination light WL toward the color separation optical system 3. The illumination light WL includes blue excitation light B1 that passes through the phosphor 34 without being wavelength-converted and is emitted from the phosphor 34, out of blue excitation light B emitted from the lighting device 2 as described below, and yellow fluorescence YL generated by wavelength conversion of the excitation light B. The illumination light WL is adjusted by the lighting device 2 so as to have a substantially uniform illuminance distribution.

[0011] As shown in FIG. 1, the color separation optical system 3 includes a first dichroic mirror 7a, a second dichroic mirror 7b, a first reflecting mirror 8a, a second reflecting mirror 8b, and a third reflecting mirror 8c. The first dichroic mirror 7a separates the illumination light WL emitted from the illumination device 2 into red light LR and a mixture of green light LG and blue light LB. Therefore, the first dichroic mirror 7a transmits the red light LR and reflects the green light LG and the blue light LB. The second dichroic mirror 7b separates the mixture of green light LG and blue light LB into green light LG and blue light LB. Therefore, the second dichroic mirror 7b reflects the green light LG and transmits the blue light LB.

[0012] The first reflecting mirror 8a is disposed in the optical path of the red light LR, and reflects the red light LR transmitted through the first dichroic mirror 7a toward the optical modulation device 4R. The second reflecting mirror 8b and the third reflecting mirror 8c are disposed in the optical path of the blue light LB, and reflect the blue light LB transmitted through the second dichroic mirror 7b, and guide the blue light LB to the optical modulation device 4B.

[0013] The light modulation device 4R modulates the red light LR according to image information while passing the light, forming a red image light. Similarly, the light modulation device 4G modulates the green light LG according to image information while passing the light, forming a green image light. The light modulation device 4B modulates the blue light LB according to image information while passing the blue light LB, forming a blue image light. Each of the light modulation device 4R, the light modulation device 4G, and the light modulation device 4B is composed of, for example, a liquid crystal panel. A polarizing plate (not shown) is disposed on the light incident side and the light exit side of each of the light modulation device 4R, the light modulation device 4G, and the light modulation device 4B. A field lens 10R that converts the red light LR incident on the light modulation device 4R into parallel light is provided on the incident side of the red light LR of the light modulation device 4R. A field lens 10G that converts the green light LG incident on the light modulation device 4G into parallel light is provided on the incident side of the green light LG of the light modulation device 4G. A field lens 10B that converts the blue light LB incident on the light modulation device 4B into parallel light is provided on the incident side of the blue light LB of the light modulation device 4B.

[0014] The light combining optical system 5 is configured by, for example, a cross dichroic prism. The light combining optical system 5 combines the image lights of the respective colors emitted from the light modulation device 4R, the light modulation device 4G, and the light modulation device 4B, and emits the combined image light toward the projection optical system 6.

[0015] The projection optical system 6 is composed of a plurality of projection lenses. The projection optical system 6 enlarges and projects the image light combined by the light combining optical system 5 onto the screen SCR. An enlarged color image is displayed on the screen SCR.

[0016] (Lighting equipment) Next, the configuration of the lighting device 2 will be described. The illumination device 2 of the first embodiment is an illumination device 2A including a light source device 11. As shown in Fig. 2, the illumination device 2A includes the light source device 11, an integrator optical system 31, a polarization conversion element 32, and a superimposing lens 33A. The integrator optical system 31 and the superimposing lens 33A configure a superimposing optical system 33.

[0017] The light source device 11 includes an array light source 20, a collimator optical system 22, a focusing optical system 23, a first phase difference plate 28A, an optical element 25A including a polarization separation element 50A, a first focusing optical system 26, a fluorescent light-emitting element 27, a second phase difference plate 28B, a second focusing optical system 29, and a diffuse reflection element 30.

[0018] The array light source 20, the collimator optical system 22, the focusing optical system 23, the first retardation plate 28A, the optical element 25A, the second retardation plate 28B, the second focusing optical system 29, and the diffuse reflection element 30 are arranged in sequence on the optical axis AX1. Meanwhile, the fluorescent light emitting element 27, the first focusing optical system 26, the optical element 25A, the integrator optical system 31, the polarization conversion element 32, and the superimposing lens 33A are arranged in sequence on the optical axis AX2. The optical axes AX1 and AX2 are in the same plane and are perpendicular to each other.

[0019] The array light source 20 includes a plurality of semiconductor lasers (light sources) 21 as solid-state light sources. The plurality of semiconductor lasers 21 are arranged in an array in a plane perpendicular to the optical axis AX1. The semiconductor lasers 21 emit, for example, blue excitation light BL as excitation light for the phosphor 34 of the fluorescent light-emitting element 27. The peak wavelength of the excitation light BL is, for example, 445 nm, but can be arbitrarily changed as long as it can excite the phosphor 34 as described above, and is determined according to the fluorescent material of the phosphor 34, and may be, for example, 460 nm. The array light source 20 emits a light beam having the excitation light BL.

[0020] The excitation light BL emitted from the array light source 20 is incident on the collimator optical system 22. The collimator optical system 22 converts the excitation light BL emitted from the array light source 20 into parallel light. The collimator optical system 22 includes, for example, a plurality of collimator lenses 22A arranged in an array. Each of the plurality of collimator lenses 22A is arranged corresponding to each of the plurality of semiconductor lasers 21.

[0021] The excitation light BL that has passed through the collimator optical system 22 is incident on the focusing optical system 23. The focusing optical system 23 adjusts the beam diameter of the excitation light BL. The focusing optical system 23 includes, for example, a convex lens 23A and a concave lens 23B.

[0022] The excitation light BL that has passed through the focusing optical system 23 is incident on the first retardation plate 28A. The first retardation plate 28A is, for example, a ½ wavelength plate that is configured to be rotatable approximately around the optical axis AX1. The excitation light BL emitted from the semiconductor laser 21 is linearly polarized light. By appropriately setting the rotation angle of the first retardation plate 28A, the excitation light BL that passes through the first retardation plate 28A can be converted into a light beam that contains an S-polarized component and a P-polarized component with respect to the optical element 25A at a predetermined ratio. By rotating the first retardation plate 28A, the ratio of the S-polarized component and the P-polarized component can be changed.

[0023] The excitation light BL, which contains an S-polarized component and a P-polarized component and is generated by passing through the first retardation plate 28A, is incident on the optical element 25A. The optical element 25A is, for example, a dichroic prism having wavelength selectivity. The dichroic prism has an inclined surface 50a that is in the same plane and forms an angle of 45° with respect to the optical axis AX1 and the optical axis AX2.

[0024] The inclined surface 50a is provided with a polarization separation element 50A having wavelength selectivity. The polarization separation element 50A separates the excitation light BL into an S-polarized component of the excitation light BL with respect to the polarization separation element 50A. S and P-polarized blue light BL P The polarization separation element 50A has a function of separating the incident excitation light BL S The blue light BL P The polarization separation element 50A has a color separation function of transmitting the fluorescence YL, which has a different wavelength band from the excitation light BL, regardless of the polarization state of the fluorescence YL.

[0025] The excitation light BL emitted from the polarization separation element 50A S The excitation light BL enters the first focusing optical system 26.S The first focusing optical system 26 focuses the excitation light BL toward the phosphor 34. The first focusing optical system 26 includes, for example, a first lens 26A and a second lens 26B. S The light is incident on the fluorescent light emitting part 101 of the fluorescent light emitting element 27 in a condensed state.

[0026] The fluorescent light emitting element 27 includes a reflective fluorescent light emitting section 100 having a fluorescent material 34 and a reflective layer 37, a substrate 35 supporting the fluorescent light emitting section 100, and a fixing member 36 fixing the fluorescent light emitting section 100 to the substrate 35. The fluorescent material 34 is fixed to the substrate 35 by the fixing member 36 provided between the side surface of the fluorescent material 34 and the substrate 35. The excitation light BL of the fluorescent material 34 S The surface opposite to the side where the light is incident is in contact with the substrate 35 .

[0027] The phosphor 34 is excited by the excitation light BL S The fluorescent material is excited by absorbing the excitation light BL. S The fluorescent material excited by the excitation light BL emits yellow fluorescence YL having a peak wavelength in the wavelength range of, for example, 500 nm to 700 nm. S The peak wavelength (wavelength) differs from that of the fluorescent material and is determined by the fluorescent material.

[0028] Excitation light BL for phosphor 34 S A reflective layer 37 is provided on the side opposite to the side where the light is incident. The reflective layer 37 reflects a component of the fluorescence YL generated by the phosphor 34 that travels toward the substrate 35. A portion of the fluorescence YL generated by the phosphor 34 is reflected by the reflective layer 37 and emitted to the outside of the phosphor 34. The other portion of the fluorescence YL generated by the phosphor 34 is emitted to the outside of the phosphor 34 without passing through the reflective layer 37.

[0029] A heat sink 38 is disposed on the surface of the substrate 35 opposite to the surface supporting the phosphor 34. In the fluorescent light emitting element 27, heat generated in the phosphor 34 can be dissipated via the heat sink 38, so that thermal deterioration of the phosphor 34 can be prevented.

[0030] The fluorescence YL emitted from the phosphor 34 is unpolarized light. The fluorescence YL passes through the first light collecting optical system 26 and then enters the polarization separation element 50A. The fluorescence YL that enters the polarization separation element 50A travels from the polarization separation element 50A toward the integrator optical system 31.

[0031] On the other hand, the P-polarized blue light BL emitted from the polarization separation element 50A P The P-polarized blue light BL emitted from the polarization separation element 50A is incident on the second retardation plate 28B. The second retardation plate 28B is, for example, a quarter-wave plate arranged in the optical path between the polarization separation element 50A and the diffuse reflection element 30. Therefore, the P-polarized blue light BL P is polarized by the second retardation plate 28B into right-handed circularly polarized blue light BL C 1, the blue light BL C 1 is focused and incident on the diffuse reflecting element 30.

[0032] The diffuse reflection element 30 is disposed on the opposite side of the phosphor 34 in the polarization separation element 50A, and reflects the blue light BL C The diffuse reflector 30 diffuses and reflects blue light BL 1 toward the polarization separation element 50A. C It is preferable to use an element that causes Lambertian reflection of 1 while not disturbing the polarization state.

[0033] Hereinafter, the light reflected in a diffused state by the diffuse reflecting element 30 will be referred to as blue light BL C 2. Blue light BL C By diffusing and reflecting the blue light BL1, a blue light BL2 with a substantially uniform illuminance distribution is generated. C For example, right-handed circularly polarized blue light BL C 1 is left-handed circularly polarized blue light BL C 2. Blue light BL C The light 2 is converted into parallel light by the second focusing optical system 29, and then enters the second retardation plate 28B again.

[0034] Left-handed circularly polarized blue light BL C 2 is polarized blue light BL by the second retardation plate 28B. S 1. S-polarized blue light BL S 1 is reflected by the polarization separation element 50A toward the integrator optical system 31.

[0035] blue light BL S The blue light BL1 is used as illumination light WL together with the fluorescent light YL transmitted through the polarization separation element 50A. S The blue light BL1 and the fluorescent light YL are emitted in the same direction from the polarization separation element 50A. S White illumination light WL is generated by mixing 1 with yellow fluorescence YL.

[0036] The illumination light WL is emitted toward the integrator optical system 31. The integrator optical system 31 includes, for example, a lens array 31A and a lens array 31B. In each of the lens arrays 31A and 31B, a plurality of microlenses are arranged along a direction perpendicular to the optical axis AX2. The illumination light WL transmitted through the integrator optical system 31 is incident on the polarization conversion element 32. The polarization conversion element 32 has a polarization separation film and a retardation plate. The polarization conversion element 32 converts the illumination light WL, which includes unpolarized fluorescence YL, into linearly polarized light.

[0037] The illumination light WL transmitted through the polarization conversion element 32 is incident on the superimposing lens 33A. The superimposing lens 33A homogenizes the distribution of illuminance by the illumination light WL in the illuminated area in cooperation with the integrator optical system 31. As described above, the illumination device 2A generates the illumination light WL.

[0038] (Fluorescent emission part) First, the basic structure and principle of the nanoantenna of the fluorescence emitting unit 100 will be described. The fluorescence emission unit 100 includes a phosphor 34 and a nanoantenna group 131 arranged on an emission surface (surface) 34e of the phosphor 34. The emission surface 34e of the phosphor 34 is an interface between the inside of the phosphor 34 and an external space through which the fluorescence YL passes. The nanoantenna group 131 has a plurality of nanoantennas 132. The plurality of nanoantennas 132 are arranged at a predetermined interval from each other on the emission surface 34e. The nanoantenna 132 is formed, for example, in a columnar shape. The shape of the bottom surface of the nanoantenna 132 is, for example, circular, but is not limited to circular, and may be rectangular, a polygon other than a rectangle, a star, or the like. However, the planar shape of the bottom surface of the nanoantenna 132 is preferably a shape with high rotational symmetry with respect to the center in order to suppress the influence on the polarization characteristics of the fluorescence YL, and is preferably, for example, a perfect circle or a regular polygon.

[0039] As shown in FIG. 3, the nanoantennas 132 are arranged in a row along one direction at a predetermined interval, and are further arranged in a plurality of rows in a direction perpendicular to the one direction. In one of two rows adjacent to each other in a direction perpendicular to the one direction, the center of the nanoantennas 132 in the other row is arranged at the midpoint between the centers of two nanoantennas 132 adjacent to each other in the one direction. In other words, the nanoantennas 132 in the plurality of rows are arranged, for example, alternately. It is only necessary that the interval between the centers of the plurality of nanoantennas 132 is constant and a periodic structure can be formed as the nanoantenna group 131. The centers of the nanoantennas 132 in a row formed by the plurality of nanoantennas 132 may be aligned in the same position among the plurality of rows.

[0040] 3 and 4, the diameter 132d of the bottom surface of the nanoantenna 132 is, for example, about 250 nm. The height 132h of the nanoantenna 132 is, for example, about 50 nm. The distance 132s between the centers of two adjacent nanoantennas 132 on the emission surface 34e is, for example, about 450 nm. The diameter 132d, the height 132h, and the distance 132s are appropriately set in consideration of the principles of the nanoantenna, which will be described later, and the like.

[0041] When the nanoantenna 132 is made of a metal, when light is incident on the nanoantenna 132, the conduction electrons in the vicinity of the interface of the nanoantenna 132 oscillate collectively, causing localized surface plasmon resonance (LSPR). When the diameter 132d or the interval 132s is equal to or shorter than the wavelength of the incident light, the conduction electrons of each nanoantenna 132 oscillate due to the electric field polarization of the incident light confined in the nanoantenna group 131, causing a strong electric field enhancement at the end face of the nanoantenna 132. Because the nanoantenna group 131 has a periodic structure, when light is incident on the nanoantenna 132, diffraction also occurs.

[0042] As shown in FIG. 5, the diffraction with a diffraction angle of 90° with respect to the light L incident on the fluorescence emission unit 100 is called Rayleigh anomaly, and is the diffraction along a direction parallel to the emission surface 34e of the phosphor 34. In the Rayleigh anomaly, the LSPR and the 90° diffracted light DL are combined, and the phases of the multiple nanoantennas 132 resonate in unison, causing a surface lattice resonance (LSR). It is known that the LSR can control the radiation angle of the fluorescent light source for the lighting device and suppress color unevenness (for example, references such as R. Kamakura et al.; Journal of Applied Physics, Vol. 124, p. 213105 (2018) can be referred to).

[0043] FIG. 6 shows a simulation result of the emission angle distribution of the fluorescence generated from the phosphor 34 when the nanoantenna group 131 is not formed on the phosphor 34. Meanwhile, FIG. 7 shows a simulation result of the emission angle distribution of the fluorescence generated from the phosphor 34 when the nanoantenna group 131 is formed on the emission surface 34e of the phosphor 34. In the simulation, it is assumed that the material of the nanoantenna 132 is Ag, and the diameter 132d of the nanoantenna 132 when the nanoantenna group 131 is formed is set to 150 nm, the height 132h is set to 150 nm, and the distance 132s between the centers of the nanoantennas 132 is set to 400 nm. As can be seen from a comparison between FIG. 6 and FIG. 7, the emission angle distribution of the fluorescence can be narrowed by providing the nanoantenna group 131 on the emission surface 34e of the phosphor 34.

[0044] The peak wavelength of the LSPR is determined by the wavelength dispersion characteristic of the dielectric constant of the material of the nanoantenna 132. For example, when the material of the nanoantenna 132 is aluminum (Al), the peak wavelength of the LSPR is around 400 nm. When the material of the nanoantenna 132 is silver (Ag) or gold (Au), the peak wavelength of the LSPR is around 500 nm, and high extinction (scattering) occurs. The peak wavelength of the LSPR can be adjusted by appropriately selecting and setting the dielectric constant and other characteristics of the material of the nanoantenna 132 and each dimension of the nanoantenna 132. However, if the application of the fluorescence emitting unit 100 is lighting, it is preferable that the LSPR occurs efficiently in the visible wavelength range and that the peak wavelength of the LSPR is included in the visible wavelength range. Therefore, it is preferable that the material of the nanoantenna 132 of the fluorescence emitting unit 100 for a lighting device is Ag or the like that has a peak wavelength of the LSPR in the visible wavelength range.

[0045] The phosphor 34 of the fluorescent light emission unit 100 for a projector is the part that is most required to have heat resistance among the parts constituting the projector, because excitation light having a high power of the watt (W) level is incident in a concentrated state. The nanoantenna group 131 is required to be able to realize efficient scattering, and also to be resistant to thermal degradation caused by temperature rise, or to suppress thermal degradation. The nanoantenna 132 made of a metal such as Ag is more susceptible to thermal degradation when irradiated with high-power excitation light, as compared to non-metallic materials such as dielectrics.

[0046] In addition to metals that have high heat absorption and are prone to thermal degradation, dielectrics and semiconductors such as silicon (Si) can be used as materials for the nanoantenna 132. When a dielectric or semiconductor is used as the material for the nanoantenna 132, the principle of the decrease in the vicinity of the emission surface 34e of the phosphor 34 is based on the LSR caused by the combination of Mie scattering and Rayleigh anomaly, not the combination of the above-mentioned LSPR and Rayleigh anomaly.

[0047] Mie resonance is a phenomenon that occurs when light incident on a microstructure with a high refractive index is trapped and resonates inside the microstructure. The state of Mie resonance is determined according to the shape of the nanoantenna 132 and the refractive index of the material. When the material of the nanoantenna 132 is a dielectric or semiconductor, extinction (scattering) with a peak wavelength in a specific wavelength range occurs according to the shape of the nanoantenna 132 and the characteristics of the material, similar to LSPR when the material is a metal. Materials that cause Mie resonance include dielectrics such as titanium oxide (TiO2), silicon nitride (SiN), gallium phosphide (GaP), and aluminum oxide (Al2O3), semiconductors such as Si, and insulators such as silicon oxide (SiO2).

[0048] The melting point of Ag, which is an example of a material that generates LSPR, is 961° C., whereas the melting point of a material that generates Mie resonance is higher than that of Ag. For example, the melting point of Si is 1414° C., the melting point of TiO2 is 1834° C., and the melting point of SiO2 is 1700° C. From the viewpoint of heat resistance, dielectrics such as TiO2 and semiconductors such as Si are more preferable as materials for the nanoantenna 132 than metals such as Ag.

[0049] As can be seen from the results disclosed in the above-mentioned references, when a dielectric material such as Al2O3 is used as the material for the nanoantenna 132, the scattering value (scattering cross section) is smaller and the radiated light intensity is weaker than when a metal such as Al is used. On the other hand, materials such as Si have a high optical absorption coefficient in the region of 400 nm to 500 nm in the visible wavelength range, so the radiated light intensity is easily reduced by optical absorption.

[0050] Next, the basic structure and principle of the nanoantenna of the fluorescent light emitting section 101 of the first embodiment will be described. As shown in Fig. 8 and Fig. 9, the fluorescent light emitting section 101 includes a phosphor 34, a first nanoantenna group 111 and a second nanoantenna group 121 arranged on an emission surface 34e of the phosphor 34, and a reflecting layer 37. Note that in the diagrams explaining the configuration of the irradiation device such as Fig. 2, the nanoantenna groups such as the first nanoantenna group 111 and the second nanoantenna group 121 are omitted. As shown in Fig. 8 and Fig. 9, in the fluorescent light emitting section 101, the nanoantenna group 131 of the fluorescent light emitting section 100 described above is composed of the first nanoantenna group 111 and the second nanoantenna group 121, and the reflecting layer 37 is provided on the fluorescent light 34.

[0051] It is preferable to use a material having excellent heat resistance and surface processability for the phosphor 34. For example, a phosphor in which fluorescent particles are dispersed in an inorganic binder such as alumina, or a phosphor in which fluorescent particles are sintered without using a binder, is preferably used as the phosphor 34. The fluorescent particles may be particles formed using one type of material, or may be a mixture of particles formed using two or more types of materials.

[0052] The first nanoantenna group 111 has a plurality of first nanoantennas 112. When viewed in a plan view along the thickness direction of the phosphor 34, the plurality of first nanoantennas 112 are arranged on the emission surface 34e (where the excitation light BL S The excitation light BL is incident on the incident surface of the S The second nanoantenna group 121 has a plurality of second nanoantennas 122. When viewed in a plan view along the thickness direction of the phosphor 34, the second nanoantennas 122 are arranged at predetermined intervals from each other within the irradiation area BAR on the emission surface 34e. Any second nanoantenna 122 that overlaps with the irradiation area BAR even partially is considered to be arranged within the irradiation area BAR. The excitation light BL S The light is collected by the first collecting optical system 26 shown in Fig. 2 and enters the irradiation area BAR shown in Fig. 8 and Fig. 9. The second nanoantenna group 121 is disposed within the irradiation area BAR, for example, at approximately the center of the emission surface 34e.

[0053] The first nanoantenna 112 and the second nanoantenna 122 are formed, for example, in a cylindrical shape, similar to the above-mentioned nanoantenna 132. The shape of the bottom surface of the first nanoantenna 112 and the second nanoantenna 122 is not limited to a circle, and may be a rectangle, a polygon other than a rectangle, a star, or the like. However, for the same reason as explained for the nanoantenna 132, the shape of the bottom surface of the first nanoantenna 112 and the second nanoantenna 122 is preferably a shape having high rotational symmetry with respect to the center, for example, a perfect circle or a regular polygon.

[0054] The multiple first nanoantennas 112 and the multiple second nanoantennas 122 form a periodic structure on the nano-order as a whole. On the emission surface 34e of the phosphor 34, the distance 112s between the centers of adjacent first nanoantennas 112, the distance 122s between the centers of the second nanoantennas 122, and the distance 123s between the centers of the first nanoantennas 112 and the second nanoantennas 122 are all equal.

[0055] If the intervals 112s, 122s, and 123s are collectively referred to as the nanoantenna pitch a, the nanoantenna pitch a is set within a range that satisfies the conditional expression for the Rayleigh anomaly in the emission wavelength range from the emission surface 34e of the phosphor 34, the radiation angle of which is to be controlled. As illustrated in Fig. 8, the conditional expression for the Rayleigh anomaly of a triangular lattice in which a plurality of first nanoantennas 112 and a plurality of second nanoantennas 122 are alternately arranged is expressed by the following formula (1).

[0056]

number

[0057] In the above formula (1), k out represents the wave vector of the fluorescence YL emitted from the first nanoantenna group 111 and the second nanoantenna group 121, and k in represents excitation light BL incident on the first nanoantenna group 111 and the second nanoantenna group 121. S In this formula, m1 and m2 represent integers that determine the orders of the diffracted light in the first nanoantenna group 111 and the second nanoantenna group 121.

[0058] The maximum width 112d of the bottom surface of the first nanoantenna 112 and the maximum width 122d of the bottom surface of the second nanoantenna 122 are equal to each other. The height 112h of the first nanoantenna 112 and the height 122h of the second nanoantenna 122 are equal to each other. The maximum widths 112d, 122d and the heights 112h, 122h are appropriately determined so as to satisfy the Rayleigh anomaly condition of equation (1) together with the pitch a, taking into consideration the above-mentioned nanoantenna principle, etc. The diffraction relational equation is basically determined for a single incident angle and wavelength. Since the light emitted from the phosphor 34 has a spread in the incident angle and a wide wavelength range, each representative value is extracted, and the nanoantenna pitch a and other parameters related to the first nanoantenna group 111 and the second nanoantenna group 121 are determined based on equation (1) etc. The Rayleigh anomaly condition is determined by the nanoantenna pitch a, the excitation light BL S Wavelength (incident wavelength), excitation light BL S Exit surface 34e and the refractive index around the first nanoantenna group 111 and the second nanoantenna group 121 , and is not dependent on the material of the first nanoantenna group 112 and the material of the second nanoantenna group 122 .

[0059] The first nanoantenna group 111 arranged outside the irradiation area BAR on the emission surface 34e of the phosphor 34, and the second nanoantenna group 121 arranged within the irradiation area BAR on the emission surface 34e are formed of two different materials. The material of the first nanoantenna 112 is a metal, such as Ag or Au. The material of the second nanoantenna 122 has a melting point at least higher than the melting point of the material of the first nanoantenna 112, and the excitation light BL in a state of being condensed and reaching a high power is formed of the metal. S In other words, the material of the second nanoantenna 122 has higher light stability and heat resistance than the material of the first nanoantenna 112.

[0060] The material of the second nanoantenna 122 is preferably a dielectric, semiconductor, or insulator having higher heat resistance than the material of the first nanoantenna 112, such as a metal. Examples of the dielectric include TiO2, SiN, GaP, and Al2O3. Examples of the semiconductor include Si. Examples of the insulator include SiO2. In detail, the range in which the second nanoantenna group 121 is disposed on the emission surface 34e of the phosphor 34 is determined based on the amount of excitation light BL in the second nanoantenna group 121. S The excitation light BL is irradiated onto the incident surface 121i of the S The predetermined beam diameter is preferably about the same as the so-called 1 / e 2 The diameter of the beam (excitation light BL S ) may be a diameter that provides 86.4% of the total light amount.

[0061] The range in which the first nanoantenna group 111 is arranged on the emission surface 34e is the same as the range in which the excitation light BL SThe first nanoantenna group 112 is preferably made of a metal such as Al, Ag, or Au. By forming the first nanoantenna group 111 from these metals, the radiation angle of the fluorescence YL can be efficiently controlled. In reality, scattering within the phosphor 34 causes a blur in the light-emitting area on the exit surface 34e, and the excitation light BL S The fluorescence YL is emitted from a region that is larger than the beam diameter on the emission surface 34e of the fluorescent material 34. Therefore, the fluorescence YL is also incident on the peripheral region adjacent to the irradiation region BAR. Since the amount of bleeding of the fluorescence YL on the emission surface 34e varies depending on the thickness and scattering characteristics of the fluorescent material 34, it is preferable that the area ratio and arrangement of the first nanoantenna 112 and the second nanoantenna 122 in the peripheral region are appropriately adjusted according to the amount of bleeding.

[0062] The reflective layer 37 is provided on a surface 34b opposite to the emission surface 34e of the phosphor 34. As the reflective layer 37, for example, a metal film or a dielectric multilayer film having high reflectance is used.

[0063] In the fluorescence emission unit 101 of the first embodiment, excitation light BL S SLR occurs due to a combination of Mie resonance and Rayleigh anomaly in a highly heat-resistant material such as a dielectric or semiconductor of the second nanoantenna 122 that is mainly arranged in the irradiation area BAR of the second nanoantenna 122, and SLR occurs due to a combination of LSPR and Rayleigh anomaly outside the area where the second nanoantenna 122 is arranged. As a result, it is possible to achieve both highly efficient extraction of fluorescence YL from the phosphor 34, a narrow radiation angle, and improved heat resistance.

[0064] In the fluorescence emission unit 101 of the first embodiment, the electric fields of the excitation light BL, B1 and fluorescence YL are enhanced in each of the first nanoantenna group 111 and the second nanoantenna group 121 by the interaction between the resonance phenomenon and the Rayleigh anomaly according to each nanoantenna group. It is considered that the electric field enhancement in the first nanoantenna group 111 formed of a metal is relatively stronger than the electric field enhancement in the second nanoantenna group 121. On the other hand, as described above, it is considered that the optical stability and heat resistance of the second nanoantenna group 121 formed of a material having a higher melting point than the metal material of the first nanoantenna 112 are higher than those of the first nanoantenna group 111. Therefore, in a plan view seen from the normal direction of the phosphor 34, at least the arrangement region NAR of the second nanoantenna group 121 is larger than the excitation light BL S The irradiation area BAR overlaps with the irradiation area BAR.

[0065] From the viewpoint of suppressing thermal deterioration of the phosphor 34 while enhancing the effect of enhancing the electric field of the excitation light BL, B1, and fluorescence YL, it is preferable to make the arrangement area of ​​the first nanoantenna group 111 as large as possible on the emission surface 34e of the phosphor 34, and to make the arrangement area of ​​the second nanoantenna group 121 as small as possible. S or the excitation light BL incident on the second nanoantenna group 121. S In detail, the arrangement area NAR of the second nanoantenna group 121 may be within a diameter range in which 50% of the total amount of light is obtained. S The light intensity should be within 1 / 2 the diameter of the 2 Whether the diameter is within the above-mentioned range or within an appropriate range other than the above-mentioned diameter can be determined depending on the heat resistance and other characteristics of the material of the first nanoantenna 112.

[0066] [Second embodiment] Next, a second embodiment of the present invention will be described with reference to FIG. Except for having a fluorescent light emission section 102, which will be described next, instead of the fluorescent light emission section 101, the projector and illumination device of the second embodiment have the same configuration as the projector 1 and illumination device 2A of the first embodiment. In the second and subsequent embodiments, configurations common to the first and other previously described embodiments are given the same reference numerals as those in the previously described embodiments, and descriptions thereof will be omitted.

[0067] 10, the fluorescence emission section 102 of the second embodiment has a base layer 141 provided on the emission surface 34e of the phosphor 34, the first nanoantenna group 111 and the second nanoantenna group 121 are arranged on a surface 141a of the base layer 141, and a cover layer 142 is provided on the exposed end faces of the first nanoantenna group 111 and the second nanoantenna group 121. In other words, the fluorescence emission section 102 includes the phosphor 34, the first nanoantenna group 111, the second nanoantenna group 121, the reflective layer 37, the base layer 141, and the cover layer 142.

[0068] The base layer 141 is provided on the entire emission surface 34e of the phosphor 34. The cover layer 142 covers the side surfaces 112c of the multiple first nanoantennas 112 arranged on the emission surface 34e in contact with the emission surface 34e, and the bottom surface 112a of the two bottom surfaces of the first nanoantenna 112 formed in a columnar shape, which is opposite to the side in contact with the emission surface 34e.

[0069] By using the same material for the base layer 141 and the cover layer 142, the refractive indexes around the first nanoantenna group 111 and the second nanoantenna group 121 are made substantially the same. As a result, a stronger SLR is generated than in the fluorescence emitter 101 of the first embodiment, and the intensity of the light radiated from the fluorescence emitter 102 is increased.

[0070] When dielectric materials having different refractive indices are used as the materials of the cover layer 142 and the base layer 141, a deviation occurs between the Rayleigh anomaly condition for the refractive index of the cover layer 142 and the Rayleigh anomaly condition for the refractive index of the base layer 141. As a result, the optical energy is dispersed into the diffracted light DL in different directions by the base layer 141 and the cover layer 142.

[0071] The thickness of the dielectric material surrounding each of the first nanoantenna group 111 and the second nanoantenna group 121 may be within a range in which near-field light such as LSPR can act as described above, and is preferably, for example, 10 nm or more and 100 nm or less. In addition, in order not to impede Mie resonance due to light confinement in the first nanoantenna group 111 and the second nanoantenna group 121, the following relationship must be satisfied: "the refractive index of the cover layer 142 is lower than the refractive index of the first nanoantenna 112."

[0072] [Third embodiment] Next, a third embodiment of the present invention will be described with reference to FIG. Except for having a fluorescent light emission section 103, which will be described next, instead of the fluorescent light emission section 101, the projector and illumination device of the third embodiment have the same configuration as the projector 1 and illumination device 2A of the first embodiment.

[0073] In the fluorescence emission unit 103 of the third embodiment, compared to the configuration of the fluorescence emission unit 101 of the first embodiment, the maximum width 122d of the second nanoantenna 122 may be different from the maximum width 112d of the first nanoantenna 112 as shown in Fig. 11. In Fig. 11, the maximum width 122d of the second nanoantenna 122 is shorter than the maximum width 112d of the first nanoantenna 112. Since the nanoantenna pitch a is a factor that determines the diffraction angle of the Rayleigh anomaly, it is assumed that the intervals 112s, 122s, and 123s of the first nanoantenna 112 and the second nanoantenna 122 are the same. On the other hand, the maximum widths 112d, 122d and the heights 112h, 122h of the first nanoantenna 112 and the second nanoantenna 122 are factors that determine the resonance conditions for each nanoantenna. In other words, the maximum widths 112d, 122d and the heights 112h, 122h are factors that determine the conditions for LSPR in the first nanoantenna group 111 and Mie resonance in the second nanoantenna group 121.

[0074] As an example of an element that determines the LSPR conditions in the first nanoantenna group 111, we focused on the maximum width (diameter) 112d of the first nanoantenna 112. We performed a simulation of the reflection spectrum distribution when the material of the first nanoantenna 112 was Ag and the maximum width 112d was changed. The parameters in the simulation other than the maximum width 112d were set as follows. Note that i is an imaginary unit. *Refractive index of Ag: 0.135+i3.20 at wavelength 550nm *Nanoantenna pitch a (= the distance between the centers of adjacent first nanoantennas 112, 112); 450 nm *Height 112h of the first nanoantenna 112: 50 nm In the above simulation, in order to clearly explain the change in LSPR with respect to the change in maximum width 112d, only the first nanoantenna 112 was formed on the emission surface 34e of the phosphor 34, and the values ​​of the above parameters other than the maximum width 112d were fixed.

[0075] 12 to 14 show the simulation results when the maximum width 112d is 200 nm, 250 nm, and 300 nm. As shown by the dashed lines in Fig. 12 to 14, the wavelength range and resonance strength of the LSPR change depending on the maximum width 112d, and it can be seen that the larger the maximum width 112d, the more the peak wavelength (center wavelength) of the LSPR shifts to the longer wavelength side.

[0076] Therefore, it is necessary to optimize the maximum width 112d of the first nanoantenna 112 in accordance with the wavelength to be controlled in the radiation angle, that is, the peak wavelength of the fluorescence YL. In the fluorescence emission unit 103, since different materials and resonance phenomena are used in the region where Mie resonance acts as the principle (inside the irradiation region BAR) and the region where LSPR acts as the principle (outside the irradiation region BAR), the optimal maximum width 112d of the first nanoantenna 112 and the optimal maximum width (diameter) 122d of the second nanoantenna 122 are different from each other. By matching the wavelength range to be controlled in the radiation angle and the resonance wavelength range in each of the first nanoantenna group 111 and the second nanoantenna group 121, a nanoantenna structure with high radiation light intensity can be realized. In other words, it is preferable that the peak wavelength at which the first nanoantenna group 111 resonates due to LSPR is close to the peak wavelength of the fluorescence YL, for example, the difference between the peak wavelengths is within 50 nm. In addition, it is preferable that the peak wavelength at which the second nanoantenna group 121 resonates due to Mie resonance is close to the peak wavelength of the excitation light BL S It is preferable that the difference between the peak wavelengths is within 50 nm, for example.

[0077] In the fluorescence emission section 103 of the third embodiment, compared to the configuration of the fluorescence emission section 102 of the second embodiment, the maximum width 122d of the second nanoantenna 122 may be different from the maximum width 112d of the first nanoantenna 112, depending on the resonance phenomenon acting in each nanoantenna group as described above.

[0078] [Fourth embodiment] Next, a fourth embodiment of the present invention will be described with reference to FIG. Except for having a fluorescent light emission section 104, which will be described next, instead of the fluorescent light emission section 101, the projector and illumination device of the fourth embodiment have the same configuration as the projector 1 and illumination device 2A of the first embodiment.

[0079] The fluorescence emission section 104 of the fourth embodiment differs from the fluorescence emission section 101 of the first embodiment in that the first nanoantenna group 111 and the second nanoantenna group 121 are disposed inside a fluorescent layer (phosphor) 140. As shown in Fig. 15, the fluorescence emission section 104 differs from the fluorescence emission section 101 of the first embodiment in that a transparent substrate 160 is disposed instead of the phosphor 34, and excitation light BL S The fluorescent layer 140 is provided so as to cover the surface 160a of the transparent substrate 160 exposed on the incident side of the light, the first nanoantenna group 111, and the second nanoantenna group 121. In other words, the fluorescent light emission unit 102 includes the transparent substrate 160, the first nanoantenna group 111, the second nanoantenna group 121, the reflective layer 37, and the fluorescent layer 140.

[0080] The first nanoantenna group 111 and the second nanoantenna group 121 are irradiated with excitation light BL S The first nanoantenna 112 is provided on the incident surface 160a of the second nanoantenna 122. The dimensions and materials of the maximum width 112d and height 112h of the first nanoantenna 112, the maximum width 122d and height 122h of the second nanoantenna 122, and the nanoantenna pitch a can be considered to be similar to the dimensions and materials of the first nanoantenna group 111 and the second nanoantenna group 121 of the fluorescence emitting unit 101 in the first embodiment.

[0081] In the manufacturing process of the first nanoantenna group 111 and the second nanoantenna group 121, if a material that generates air bubbles inside the phosphor when formed into a phosphor, such as sintered YAG (yttrium aluminum garnet) phosphor particles, is used for each phosphor 34 of the above-mentioned fluorescence emission sections 101-103, unevenness will occur on the emission surface 34e. If unevenness occurs on the emission surface 34e, it will be difficult to directly manufacture the first nanoantenna group 111 and the second nanoantenna group 121 on the emission surface 34e, and a flattening process of the emission surface 34e of the phosphor 34 will be required before manufacturing the first nanoantenna group 111 and the second nanoantenna group 121, increasing the number of processes for manufacturing the fluorescence emission section.

[0082] The transparent substrate 160 is transparent at least in the wavelength bands of the excitation light BLS and the fluorescence YL. S It is preferable that the transparent substrate 160 has a total light transmittance of 90% or more for the light in each wavelength band of the fluorescent YL. As the transparent substrate 160, for example, a substrate made of quartz (SiO2) or the like is suitably used.

[0083] The fluorescent particles contained in the fluorescent layer 140 may be, for example, a YAG-based phosphor. The fluorescent particles may be one type, or may be a mixture of particles formed using two or more types of materials. As with the phosphor 34, it is preferable to use a material having excellent heat resistance and surface processability for the fluorescent layer 140. When a dye phosphor such as BASF's Lumogen F series dye is used as the material for the fluorescent layer 140, the first nanoantenna group 111 and the second nanoantenna group 121 can be easily arranged in the thickness direction inside the fluorescent layer 140 by applying the above-mentioned material in the manufacturing process of the fluorescent layer 140.

[0084] The reflective layer 37 is provided on the surface 160b of the transparent substrate 160 opposite to the surface 160a. SA portion of the fluorescence YL emitted from the fluorescent layer 140 excited by the blue light BL and the blue light BL that passes through the fluorescent layer 140 pass through the transparent substrate 160, are reflected by the reflective layer 37, pass through the transparent substrate 160 and the fluorescent layer 140, and are emitted from the fluorescent emission section 104.

[0085] According to the fluorescence emitting unit 104 of the fourth embodiment, like the fluorescence emitting unit 101 of the first embodiment, the excitation light BL S In the irradiation area BAR, a highly heat-resistant material such as a dielectric or semiconductor is used as the material of the second nanoantenna 122, and outside the irradiation area BAR, a metal is used as the material of the first nanoantenna 112. As a result, the emission angle of the fluorescence YL can be efficiently controlled, and it is possible to simultaneously extract the fluorescence YL from the fluorescent layer 140 with high efficiency, narrow the emission angle, and improve heat resistance.

[0086] [Fifth embodiment] Next, a fifth embodiment of the present invention will be described with reference to FIG. Except for having a fluorescent light emission section 105, which will be described next, instead of the fluorescent light emission section 101, the projector and illumination device of the fifth embodiment have the same configuration as the projector 1 and illumination device 2A of the first embodiment.

[0087] The fluorescence emission section 105 of the fifth embodiment differs from the fluorescence emission section 102 of the second embodiment in that a first nanoantenna group 111, a second nanoantenna group 121, a base layer 141, and a cover layer 142 are disposed inside a fluorescent layer 140. As shown in Fig. 16, the fluorescence emission section 105 differs from the fluorescence emission section 102 of the second embodiment in that a transparent substrate 160 is disposed instead of the phosphor 34, and excitation light BL S The fluorescent layer 140 is provided so as to cover the surface 141a of the base layer 141 exposed on the incident side and the cover layer 142. That is, the fluorescent light emission unit 105 includes the transparent substrate 160, the base layer 141, the cover layer 142, the first nanoantenna group 111, the second nanoantenna group 121, the reflective layer 37, and the fluorescent layer 140.

[0088] In the fluorescence emitting section 105, as in the fluorescence emitting section 102 of the second embodiment, the same material is used for the base layer 141 and the cover layer 142, so that the refractive indexes around the first nanoantenna group 111 and the second nanoantenna group 121 are approximately the same. According to such a fluorescence emitting section 105, a stronger SLR is generated than in the fluorescence emitting section 104 of the fourth embodiment, and the intensity of the light emitted from the fluorescence emitting section 105 can be increased. The thicknesses of the base layer 141 and the cover layer 142 around each of the first nanoantenna group 111 and the second nanoantenna group 121 may be within a range in which the influence of near-field light such as LSPR is exerted, and are preferably, for example, 10 nm or more and 100 nm or less. In addition, for the same reason as that explained in the second embodiment, it is necessary that the refractive index of the cover layer 142 is lower than the refractive index of the first nanoantenna 112.

[0089] [Sixth embodiment] Next, a sixth embodiment of the present invention will be described with reference to FIG. Except for having a fluorescent light emission section 106, which will be described next, instead of the fluorescent light emission section 101, the projector and illumination device of the sixth embodiment have the same configuration as the projector 1 and illumination device 2A of the first embodiment.

[0090] The fluorescence emission section 106 of the sixth embodiment differs from the fluorescence emission section 103 of the third embodiment in that a first nanoantenna group 111 and a second nanoantenna group 121 are disposed inside a fluorescent layer 140. As shown in Fig. 17, the fluorescence emission section 106 differs from the fluorescence emission section 103 of the third embodiment in that a transparent substrate 160 is disposed instead of the phosphor 34, and excitation light BL S The fluorescent layer 140 is provided so as to cover the surface 160a of the transparent substrate 160 exposed on the incident side of the light, the first nanoantenna group 111, and the second nanoantenna group 121. In other words, the fluorescent light emission unit 106 includes the transparent substrate 160, the first nanoantenna group 111, the second nanoantenna group 121, the reflective layer 37, and the fluorescent layer 140.

[0091] In the fluorescence emitting section 106 of the sixth embodiment, the maximum width 122d of the second nanoantenna 122 may be different from the maximum width 112d of the first nanoantenna 112 as shown in FIG. 17, in comparison with the configuration of the fluorescence emitting section 104 of the fourth embodiment. FIG. 17 shows an example in which the maximum width 122d of the second nanoantenna 122 is shorter than the maximum width 112d of the first nanoantenna 112. As described in the third embodiment, the nanoantenna pitch a is a factor that determines the diffraction angle of the Rayleigh anomaly, so that the intervals 112s, 122s, and 123s of the first nanoantenna 112 and the second nanoantenna 122 are the same as each other. On the other hand, the maximum widths 112d, 122d and the heights 112h, 122h of the first nanoantenna 112 and the second nanoantenna 122 are determined according to the conditions of LSPR in the first nanoantenna group 111 and Mie resonance in the second nanoantenna group 121.

[0092] For the same reasons as those explained in the third embodiment, in the fluorescence emitting unit 106, different materials and resonance phenomena are used in the region where Mie resonance acts as the principle (inside the irradiation region BAR) and the region where LSPR acts as the principle (outside the irradiation region BAR), so that the optimum maximum width (diameter) 112d of the first nanoantenna 112 and the optimum maximum width (diameter) 122d of the second nanoantenna 122 are different from each other. In each of the first nanoantenna group 111 and the second nanoantenna group 121, a nanoantenna structure with strong radiated light intensity can be realized by matching the wavelength range for which the radiation angle is controlled with the resonance wavelength range.

[0093] [Seventh embodiment] Next, a seventh embodiment of the present invention will be described with reference to FIGS. The projector of the seventh embodiment has a similar configuration to the projector 1 of the first embodiment, except that the projector has an illumination device 2B, which will be described next, instead of the illumination device 2A.

[0094] (Lighting equipment) The illumination device 2 of the seventh embodiment is an illumination device 2B including a light source device 12. As shown in Fig. 18, the illumination device 2B includes a light source device 12, an integrator optical system 31, a polarization conversion element 32, and a superimposing lens 33A.

[0095] Light source device 12 includes an array light source 20, a collimator optical system 22, a collecting optical system 42, a dichroic film 52, a transmissive fluorescent light emission section 150, and a pickup optical system 60. The array light source 20, the collimator optical system 22, the collecting optical system 42, the fluorescent light emission section 150, and the pickup optical system 60 are arranged in sequence on the optical axis AX2.

[0096] The array light source 20 includes a plurality of semiconductor lasers (light sources) 21 as solid-state light sources. The plurality of semiconductor lasers 21 are arranged in an array in a plane perpendicular to the optical axis AX2.

[0097] The light-collecting optical system 42 is composed of, for example, one convex lens 42A. The light-collecting optical system 42 is disposed on the optical axis AX2 of the excitation light BL emitted from the array light source 20, and collects the excitation light BL, which has been converted into parallel light by the collimator optical system 22, onto the fluorescence emitter 150.

[0098] The fluorescence emitting section 150 has a function of transmitting a portion of the blue excitation light BL emitted from the array light source 20 and converting the remaining excitation light BL into fluorescence YL. The fluorescence emitting section 150 contains phosphor particles that absorb the remaining excitation light B and emit yellow fluorescence YL containing red light and green light. The peak wavelength of the emission intensity of the fluorescence YL is, for example, about 550 nm.

[0099] The dichroic film 52 is provided on the incident side of the fluorescence emission section 150 on which the excitation light BL is incident, and is disposed adjacent to the fluorescence emission section 150 in the direction along the optical axis AX2. The dichroic film 52 transmits the excitation light BL and reflects the fluorescence YL. The fluorescence YL and a portion of the excitation light BL that has transmitted through the fluorescence emission section 150, i.e., blue light, are combined to generate white illumination light WL.

[0100] The pickup optical system 60 includes, for example, a pickup lens 6 2 and pickup lens 6 4 The pickup optical system 60 takes in the illumination light WL emitted from the fluorescence emitter 150, converts it into approximately parallel light, and emits it toward the integrator optical system 31. The integrator optical system 31 includes, for example, a lens array 31C and a lens array 31D. In each of the lens arrays 31C and 31D, a plurality of microlenses are arranged along a direction perpendicular to the optical axis AX2.

[0101] As described in the illumination device 2A of the first embodiment, the illumination light WL that enters the integrator optical system 31 and then transmits through the integrator optical system 31 enters the polarization conversion element 32. The polarization conversion element 32 converts the illumination light WL containing unpolarized fluorescence YL into linearly polarized light. The illumination light WL that transmits through the polarization conversion element 32 generates illumination light WL with a uniform illuminance distribution in the illuminated area through cooperation of the superimposing lens 33A and the integrator optical system 31. As described above, the illumination device 2B generates illumination light WL.

[0102] According to the illumination device 2B of the seventh embodiment, the optical system can be arranged substantially linearly along the optical axis AX2, and the optical system can be easily assembled and designed.

[0103] (Fluorescent emission part) The fluorescence emission section 151 of the seventh embodiment does not include the reflective layer 37 in the configuration of the fluorescence emission section 101 of the first embodiment, and uses the above-mentioned dichroic film 52 instead of the reflective layer 37. That is, the fluorescence emission section 151 includes a phosphor 34, a first nanoantenna group 111, and a second nanoantenna group 121.

[0104] In the fluorescence emission unit 151 of the first embodiment, the excitation light BL and the fluorescence YL are emitted from the emission surface 34e of the phosphor 34, and the excitation light BL SIn the fluorescence emission unit 151 of the seventh embodiment, the excitation light BL and the fluorescence YL are emitted from the emission surface 34e of the phosphor 34, but the excitation light BL emitted from the focusing optical system 42 is incident on the phosphor 34 from a surface (incident surface) 34b opposite to the emission surface 34e of the phosphor 34.

[0105] The first nanoantennas 112 are arranged on the emission surface 34e (emitted light BL S The second nanoantenna group 121 is arranged at a nanoantenna pitch a outside the irradiation area BAQ of the excitation light BL emitted from the emission surface 34e of the phosphor 34. The irradiation area BAQ has approximately the same size as the irradiation area BAR described in the first embodiment, but is actually slightly larger than the irradiation area BAR due to the thickness of the phosphor 34 and the degree of diffraction of the emitted light TL. The emitted light TL is blue light that enters the pickup optical system 60 shown in FIG. 18. In detail, the range in which the second nanoantenna group 121 is arranged on the emission surface 34e of the phosphor 34 is preferably approximately the same as a predetermined beam diameter of the emitted light TL that is irradiated to the emission surface 121e of the emitted light TL in the second nanoantenna group 121. The predetermined beam diameter is a so-called 1 / e 2 Alternatively, it may be a diameter at which 86.4% of the total light amount of the beam (emitted light TL) incident on the second nanoantenna group 121 is obtained.

[0106] According to the fluorescence emitting unit 151 of the seventh embodiment, SLR occurs due to a combination of Mie resonance and Rayleigh anomaly in the highly heat-resistant material of the second nanoantenna 122 arranged within the irradiation area BAQ of the high-power emitted light TL, and SLR occurs due to a combination of LSPR and Rayleigh anomaly in the metal material of the first nanoantenna outside the irradiation area BAQ. As a result, it is possible to achieve both highly efficient extraction of fluorescence YL from the phosphor 34, a narrow radiation angle, and improved heat resistance.

[0107] In the fluorescence emission section 151 of the seventh embodiment, the electric fields of the excitation light B1 and the fluorescence YL are enhanced in each of the first nanoantenna group 111 and the second nanoantenna group 121 by an interaction between the resonance phenomenon and the Rayleigh anomaly according to each nanoantenna group. In a plan view seen from the normal direction of the phosphor 34, at least the arrangement area NAR of the second nanoantenna group 121 overlaps with the irradiation area BAQ of the excitation light BL. From the viewpoint of suppressing thermal deterioration of the phosphor 34 while enhancing the effect of enhancing the electric field of the excitation light B1 and the fluorescence YL, the arrangement area NAR of the second nanoantenna group 121 on the emission surface 34e of the phosphor 34 is set to be smaller than the irradiation area BAQ of the excitation light BL irradiated to the emission surface 121e of the second nanoantenna group 121. S or the half-width of the light amount of the excitation light BL incident on the second nanoantenna group 121. S The diameter may be within a range in which 50% of the total light amount of the second nanoantenna group 121 can be obtained, and it is preferable that the diameter is as small as possible. S The light intensity should be within 1 / 2 the diameter of the 2 Whether the diameter is within the above-mentioned range or within an appropriate range other than the above-mentioned diameter can be determined depending on the heat resistance and other characteristics of the material of the first nanoantenna 112.

[0108] [Eighth embodiment] Next, an eighth embodiment of the present invention will be described with reference to FIG. Except for having a fluorescent light emission section 152, which will be described next, instead of the fluorescent light emission section 151, the projector and illumination device of the eighth embodiment have the same configuration as the projector and illumination device 2B of the seventh embodiment.

[0109] 20 , the fluorescence emission section 152 of the eighth embodiment has a base layer 141 provided on the emission surface 34e of the phosphor 34, the first nanoantenna group 111 and the second nanoantenna group 121 are arranged on a surface 141a of the base layer 141, and a cover layer 142 is provided on each exposed end surface of the first nanoantenna group 111 and the second nanoantenna group 121. In other words, the fluorescence emission section 152 includes the phosphor 34, the first nanoantenna group 111, the second nanoantenna group 121, the base layer 141, and the cover layer 142.

[0110] As described in the second embodiment, the same material is used for the base layer 141 and the cover layer 142, thereby making the refractive indexes around the first nanoantenna group 111 and the second nanoantenna group 121 approximately the same. According to the fluorescence emitter 152 of the eighth embodiment, a stronger SLR is generated than, for example, the fluorescence emitter 151 of the seventh embodiment, and the intensity of the light radiated from the fluorescence emitter 152 can be increased.

[0111] In addition, when dielectric materials having different refractive indices are used as the materials for cover layer 142 and base layer 141, a discrepancy will arise between the Rayleigh anomaly condition for the refractive index of cover layer 142 and the Rayleigh anomaly condition for the refractive index of base layer 141. Therefore, it is necessary to select the materials for base layer 141 and cover layer 142 to correspond to each condition.

[0112] [Ninth embodiment] Next, a ninth embodiment of the present invention will be described with reference to FIG. Except for having a fluorescent light emission section 153, which will be described next, instead of the fluorescent light emission section 151, the projector and illumination device of the ninth embodiment have the same configuration as the projector 1 and illumination device 2B of the seventh embodiment.

[0113] In the fluorescence emission section 153 of the ninth embodiment, the maximum width 122d of the second nanoantenna 122 may be different from the maximum width 112d of the first nanoantenna 112 as shown in FIG. 21, in comparison with the configuration of the fluorescence emission section 151 of the first embodiment. In FIG. 21, the maximum width 122d of the second nanoantenna 122 is shorter than the maximum width 112d of the first nanoantenna 112. As described in the third embodiment, since the nanoantenna pitch a is a factor that determines the diffraction angle of the Rayleigh anomaly, it is assumed that the intervals 112s, 122s, and 123s of the first nanoantenna 112 and the second nanoantenna 122 are the same as each other. On the other hand, it is preferable that the maximum widths 112d, 122d and the heights 112h, 122h of the first nanoantenna 112 and the second nanoantenna 122 are appropriately determined according to the resonance conditions of each nanoantenna.

[0114] For the same reasons as those explained in the third embodiment, in the fluorescence emitting section 153, different materials and resonance phenomena are used in the region where Mie resonance acts as the principle (inside the irradiation region BAQ) and the region where LSPR acts as the principle (outside the irradiation region BAQ), so that the optimum maximum width (diameter) 112d of the first nanoantenna 112 and the optimum maximum width (diameter) 122d of the second nanoantenna 122 are different from each other. By matching the wavelength range for which the radiation angle is controlled with the resonance wavelength range in each of the first nanoantenna group 111 and the second nanoantenna group 121, the fluorescence emitting section 153 of the ninth embodiment can realize a nanoantenna structure with strong radiated light intensity.

[0115] [Tenth embodiment] Next, a tenth embodiment of the present invention will be described with reference to FIG. Except for having a fluorescent light emission section 154 described next instead of the fluorescent light emission section 151, the projector and illumination device of the tenth embodiment have the same configuration as the projector 1 and illumination device 2B of the seventh embodiment.

[0116] In the fluorescence emission section 154 of the tenth embodiment, in the configuration of the fluorescence emission section 151 of the seventh embodiment, a third nanoantenna group 125 is provided on the surface 34b of the phosphor 34. When excitation light BL having high power is incident on the phosphor 34 in a state of high energy density, the temperature of the phosphor 34 rises. It is known that the rise in temperature of the phosphor 34 leads to a decrease in the wavelength conversion efficiency of the phosphor 34. Therefore, by not excessively concentrating the energy of the excitation light BL at one place, it is possible to suppress the decrease in the conversion efficiency of the phosphor 34 caused by the rise in temperature.

[0117] The third nanoantenna group 125 has a plurality of third nanoantennas 126. The plurality of third nanoantennas 126 are arranged at predetermined intervals from one another within an irradiation area BAR of the excitation light BL on the surface 34b of the phosphor 34. Any third nanoantenna 126 that overlaps even a part of the irradiation area BAR is considered to be arranged within the irradiation area BAR. The excitation light BL S is collected by the first collecting optical system 26 shown in Fig. 2 and enters the irradiation area BAR shown in Fig. 22. The third nanoantenna group 125 is disposed, for example, in the irradiation area BAR at approximately the center of the surface 34b of the phosphor 34, in contact with the dichroic film 52 shown in Fig. 18, and disposed within the dichroic film 52 in the direction along the optical axis AX2.

[0118] 22 is formed, for example, in a cylindrical shape, but is not limited to a circular shape, and may be formed in a rectangular shape, a polygonal shape other than a rectangle, or a star shape. However, for the same reason as explained for the nanoantenna 132, the shape of the bottom surface of the third nanoantenna 126 is preferably a shape that has high rotational symmetry with respect to the center, and is preferably, for example, a perfect circle or a regular polygon.

[0119] The centers of adjacent third nanoantennas 126 on the surface 34b of the phosphor 34 are spaced apart by the same distance 126s. The third nanoantenna group 125 is a diffraction grating provided to widen the beam diameter of the excitation light BL incident on the surface 34b of the phosphor 34 as much as possible and reduce the energy density. Therefore, the distance 126s between the multiple third nanoantennas 126 is appropriately determined based on the equation of the diffraction grating in accordance with the wavelength (peak wavelength or representative wavelength) of the excitation light BL and the angle at which the excitation light BL is diffracted to the phosphor 34 (diffraction angle with respect to the optical axis AX2).

[0120] The angle at which the excitation light BL is diffracted to the phosphor 34 is preferably smaller than, for example, 45°. If the angle at which the excitation light BL is diffracted to the phosphor 34 is excessively large, the bleeding in the direction perpendicular to the optical axis AX2 of the excitation light BL inside the phosphor 34 becomes large, and the beam size of the excitation light (transmitted light) B1 emitted from the phosphor 34 is enlarged, which may increase the etendue of the illumination device 2B.

[0121] The material of the third nanoantenna 126 is preferably a dielectric or semiconductor that is resistant to temperature rise in order to suppress thermal deterioration caused by the temperature rise when the third nanoantenna 126 is irradiated with high-power excitation light BL. Examples of the dielectric material include TiO2, SiN, GaP, and Al2O3.

[0122] In the fluorescence emission section 154 of the tenth embodiment, the third nanoantenna group 125 is provided in the irradiation area BAR on the surface 34b of the phosphor 34 on which the excitation light BL is incident, and therefore the excitation light BL can be diffracted to reduce the energy of the excitation light BL incident on the phosphor 34. Therefore, according to the fluorescence emission section 154 of the tenth embodiment, the energy density of the excitation light BL is reduced by the third nanoantenna group 125 provided on the incident side of the phosphor 34, and a decrease in the conversion efficiency of the phosphor 34 due to a temperature rise is suppressed, and high light utilization efficiency can be obtained.

[0123] [Eleventh embodiment] Next, an eleventh embodiment of the present invention will be described with reference to FIG. Except for having a fluorescent light emission section 155 described next instead of the fluorescent light emission section 151, the projector and illumination device of the eleventh embodiment have the same configuration as the projector 1 and illumination device 2B of the seventh embodiment.

[0124] In the fluorescence emission section 155 of the eleventh embodiment, the first nanoantenna group 111 and the second nanoantenna group 121 are arranged inside a fluorescent layer (phosphor) 140, in comparison with the configuration of the fluorescence emission section 151 of the seventh embodiment. As shown in Fig. 23, in the fluorescence emission section 155, a transparent substrate 160 is arranged instead of the phosphor 34 in the configuration of the fluorescence emission section 151 of the seventh embodiment, and the fluorescent layer 140 is provided so as to cover a surface 160a of the transparent substrate 160 exposed on the incident side of the excitation light BL, the first nanoantenna group 111, and the second nanoantenna group 121.

[0125] The first nanoantenna group 111 and the second nanoantenna group 121 are provided on a surface 160a of the transparent substrate 160 on the emission side of the excitation light B1 and the fluorescence YL. The dimensions and materials of the maximum width 112d and height 112h of the first nanoantenna 112, the maximum width 122d and height 122h of the second nanoantenna 122, and the nanoantenna pitch a are assumed to be similar to the dimensions and materials of the first nanoantenna group 111 and the second nanoantenna group 121 of the fluorescence emission unit 151 of the seventh embodiment.

[0126] The preferable conditions and materials of the fluorescent layer 140 and the transparent substrate 160 of the fluorescent light emitting portion 155 are considered to be similar to those of the fluorescent layer 140 and the transparent substrate 160 of the fluorescent light emitting portion 104 of the fourth embodiment.

[0127] In the fluorescence emitting section 155 of the eleventh embodiment, the first nanoantenna group 111 and the second nanoantenna group 121 can be easily arranged in the thickness direction inside the fluorescent layer 140 by applying a material such as the above-mentioned Lumogen F series dye without using a material that causes air bubbles when formed as a phosphor. Furthermore, according to the fluorescence emitting section 155 of the eleventh embodiment, similarly to the fluorescence emitting section 151 of the seventh embodiment, a material with high heat resistance such as a dielectric or semiconductor is used as the material of the second nanoantenna 122 in the irradiation area BAQ of the excitation light BL, and a metal is used as the material of the first nanoantenna 112 outside the irradiation area BAQ. As a result, the emission angle of the fluorescence YL can be efficiently controlled, and it is possible to simultaneously achieve highly efficient extraction of the fluorescence YL from the fluorescent layer 140, a narrow emission angle, and improved heat resistance.

[0128] [Twelfth embodiment] Next, a twelfth embodiment of the present invention will be described with reference to FIG. Except for having a fluorescent light emission section 156, which will be described next, instead of the fluorescent light emission section 151, the projector and illumination device of the twelfth embodiment have the same configuration as the projector 1 and illumination device 2B of the seventh embodiment.

[0129] In the fluorescence emission section 156 of the twelfth embodiment, compared to the configuration of the fluorescence emission section 152 of the eighth embodiment, the first nanoantenna group 111, the second nanoantenna group 121, the base layer 141 and the cover layer 142 are arranged inside the fluorescent layer 140. As shown in Fig. 24, in the fluorescence emission section 156, compared to the configuration of the fluorescence emission section 152 of the eighth embodiment, a transparent substrate 160 is arranged instead of the phosphor 34, and the fluorescent layer 140 is provided so as to cover the surface 141a of the base layer 141 and the cover layer 142 exposed on the emission side of the excitation light BL.

[0130] In the fluorescence emitting section 156, similarly to the fluorescence emitting section 102 of the second embodiment, the same material is used for the base layer 141 and the cover layer 142, so that the refractive indexes around the first nanoantenna group 111 and the second nanoantenna group 121 are substantially the same. With such a fluorescence emitting section 156, a stronger SLR is generated than in the fluorescence emitting section 155 of the tenth embodiment, and the intensity of the light radiated from the fluorescence emitting section 156 can be increased. In addition, for the same reason as that explained in the second embodiment, it is necessary that the refractive index of the cover layer 142 is lower than the refractive index of the first nanoantenna 112.

[0131] [Thirteenth embodiment] Next, a thirteenth embodiment of the present invention will be described with reference to FIG. Except for having a fluorescent light emission section 157, which will be described next, instead of the fluorescent light emission section 151, the projector and illumination device of the thirteenth embodiment have the same configuration as the projector 1 and illumination device 2B of the seventh embodiment.

[0132] In the fluorescence emitting section 157 of the thirteenth embodiment, the first nanoantenna group 111 and the second nanoantenna group 121 are disposed inside the fluorescent layer 140 as shown in Fig. 25, which is different from the configuration of the fluorescence emitting section 153 of the ninth embodiment. In the fluorescence emitting section 157, the maximum width 122d of the second nanoantenna 122 may be different from the maximum width 112d of the first nanoantenna 112 as shown in Fig. 25, which is different from the configuration of the fluorescence emitting section 155 of the eleventh embodiment. Fig. 25 shows an example in which the maximum width 122d of the second nanoantenna 122 is shorter than the maximum width 112d of the first nanoantenna 112. The preferred methods for determining the dimensions of the first nanoantenna 112 and the second nanoantenna 122 are as described in the third and sixth embodiments.

[0133] For the same reasons as those explained in the third embodiment, in the fluorescence emitting section 157 of the thirteenth embodiment, different materials and resonance phenomena are used in the region where Mie resonance acts as the principle (mainly within the irradiation region BAR) and the region where LSPR acts as the principle (mainly outside the irradiation region BAR). In each of the first nanoantenna group 111 and the second nanoantenna group 121, a nanoantenna structure with strong radiation angle intensity can be realized in the fluorescence emitting section 157 by matching the wavelength range for which the radiation angle is controlled with the resonance wavelength range.

[0134] [Fourteenth embodiment] Next, a fourteenth embodiment of the present invention will be described with reference to FIG. Except for having a fluorescent light emission section 158, which will be described next, instead of the fluorescent light emission section 151, the projector and illumination device of the fourteenth embodiment have the same configuration as the projector 1 and illumination device 2B of the seventh embodiment.

[0135] In the fluorescence emitting section 158 of the fourteenth embodiment, in the configuration of the fluorescence emitting section 155 of the eleventh embodiment, a third nanoantenna group 125 is provided within the irradiation area BAR of the surface 34b of the phosphor 34.

[0136] In the fluorescence emission section 158 of the fourteenth embodiment, the third nanoantenna group 125 is provided in the irradiation area BAR on the surface 34b of the phosphor 34 where the excitation light BL is incident, and therefore the excitation light BL can be diffracted by the third nanoantenna group 125 to reduce the energy of the excitation light BL incident on the phosphor 34. According to the fluorescence emission section 158 of the fourteenth embodiment, the energy density of the excitation light BL is reduced by the third nanoantenna group 125, and a decrease in the conversion efficiency of the phosphor 34 due to a temperature rise is suppressed, and high light utilization efficiency can be obtained.

[0137] [Fifteenth embodiment] Next, a fifteenth embodiment of the present invention will be described with reference to FIGS. The projector of the fifteenth embodiment has a similar configuration to the projector 1 of the first embodiment, except that it has an illumination device 2C, which will be described next, instead of the illumination device 2A.

[0138] (Lighting equipment) The illumination device 2 of the fifteenth embodiment is an illumination device 2C including a light source device 13. As shown in Fig. 27, the illumination device 2C includes a light source device 13, an integrator optical system 31, a polarization conversion element 32, and a superimposing lens 33A.

[0139] The light source device 13 includes an array light source 20, a collimator optical system 22, a condensing optical system 23, and a pickup optical system 60 similar to those of the illumination device 2B shown in FIG. 18, and further includes a phosphor wheel 50. The array light source 20, the collimator optical system 22, the condensing optical system 23, the dichroic film 52, the transmissive phosphor wheel 50, and the pickup optical system 60 are sequentially arranged on the optical axis AX2. However, the rotation axis O of the phosphor wheel 50 and the optical axis AX2 are shifted from each other in a direction perpendicular to the optical axis AX2. In the direction along the optical axis AX2, the phosphor wheel 50 is arranged between the condensing optical system 42 and the pickup optical system 60.

[0140] In the light source device 13, the light collecting optical system 42 collects the excitation light BL, which has been converted into parallel light by the collimator optical system 22, onto the fluorescence emitting section 150 arranged on the phosphor wheel 50. The phosphor wheel 50 includes a rotating substrate 250, the fluorescence emitting section 150, a dichroic film 52, and a motor 55. The rotating substrate 250 is made of, for example, glass or resin that is transparent to at least the excitation light BL and the fluorescence YL.

[0141] The rotatable platform 250 is formed in a circular shape when viewed from the direction of the rotation axis O, but is not limited to a circular shape and may be formed in, for example, a polygonal shape. The motor 55 rotates the rotatable platform 250 around a predetermined rotation axis O. The rotatable platform 250 rotates within a plane approximately perpendicular to the optical axis AX2 of the excitation light BL incident on the rotatable platform 250.

[0142] The dichroic film 52 and the fluorescence emission section 150 are sequentially provided on a surface 250a of the rotatable substrate 250 opposite to the side on which the excitation light BL is incident. Any of the fluorescence emission sections 151 of the seventh embodiment to the fluorescence emission section 158 of the fourteenth embodiment described above can be used for the fluorescence emission section 150. In other words, the dichroic film 52 is disposed between the surface 34b of the phosphor 34 of the fluorescence emission section 150 or the surface 160b of the transparent substrate 160 and the surface 250a of the rotatable substrate 250.

[0143] The incidence region of the excitation light BL on the rotatable substrate 250 is a predetermined region between the center of the rotatable substrate 250, i.e., the center and the outer periphery in the radial direction from the rotation axis O, and extends over the entire circumferential direction centered on the rotation axis O. That is, in a plan view from the direction along the rotation axis O, the incidence region of the excitation light BL is distributed in a ring shape with a predetermined width, as shown in FIG. 28. In the fifteenth embodiment, the second nanoantenna group 121 is formed over the entire circumferential direction centered on the rotation axis O in a region corresponding to the irradiation region BAQ of the excitation light B1 in the radial direction from the rotation axis O on the surface 250a of the rotatable substrate 250. The first nanoantenna group 111 is formed over the entire circumferential direction centered on the rotation axis O in a region larger than the irradiation region BAQ in the radial direction centered on the rotation axis O and corresponding to the irradiation region BAO of the fluorescence YL on the surface 250a.

[0144] 28 is arranged as the fluorescence emission section 150 of the phosphor wheel 50, the rotating substrate 250 may be used as the transparent substrate 160. When the fluorescence emission section 158 of the 14th embodiment is arranged as the fluorescence emission section 150 of the phosphor wheel 50, the rotating substrate 250 may be used as the transparent substrate 160. Furthermore, when the fluorescence emission section 158 of the 14th embodiment is arranged as the fluorescence emission section 150 of the phosphor wheel 50, an excitation light emission area smaller than the irradiation area BAQ in the radial direction around the rotation axis O is formed on the surface 250b of the rotating substrate 250 on the side where the excitation light BL is incident. B The third nanoantenna group 125 may be formed in a region (not shown) corresponding to the irradiation region BAR of L and covering the entire circumferential direction around the rotation axis O.

[0145] According to the fluorescence emitter 150 of the fifteenth embodiment, in the antenna region having an annular shape in plan view on the surface 250a of the rotatable substrate 250, a material such as a dielectric having higher heat resistance than metal is used in the irradiation region BAQ near the central position where the excitation light BL is incident in the radial direction, and a metal is used in the irradiation region BAO radially outward of the irradiation region BAQ, and efficient control of the radiation angle is possible by the first nanoantenna group 111 and the second nanoantenna group 121. Also, in the fluorescence emitter 150 and illumination device 2C of the fifteenth embodiment, a rotation mechanism such as a motor 55 is provided on the phosphor wheel 50, thereby suppressing the energy concentration of the excitation light BL on the phosphor 34 and enabling a high efficiency as a light source.

[0146] Although the preferred embodiment of the present invention has been described in detail above, the present invention is not limited to the specific embodiment, and various modifications and changes are possible within the scope of the gist of the present invention described in the claims. Also, the components of multiple embodiments can be combined as appropriate.

[0147] For example, in the fluorescence emission unit of each of the above-mentioned embodiments, it is assumed that the refractive index around each of the first nanoantenna group 111 and the second nanoantenna group 121 is uniform. However, in cases where the refractive index around each of the first nanoantenna group 111 and the second nanoantenna group 121 changes locally or continuously, the interval 112s between the multiple first nanoantennas 112 of the first nanoantenna group 111, the interval 122s between the second nanoantennas 122 of the second nanoantenna group 121, and the interval 123s between the first nanoantenna 112 and the adjacent second nanoantenna 122 may be different from each other depending on the change in the refractive index. In addition, each of the intervals 112s, 122s, and 123s does not necessarily have to be constant, and can be suitably set depending on the refractive index around each of the first nanoantenna group 111 and the second nanoantenna group 121.

[0148] For example, in a fluorescence emission section having a base layer 141 and a cover layer 142, if the refractive index of the cover layer 142 covering the first nanoantenna 112 and the refractive index of the cover layer 142 covering the second nanoantenna 122 are different from each other, the spacing 112s between the multiple first nanoantennas 112 and the spacing 122s between the multiple second nanoantennas 122 may be made different according to the refractive index difference of the cover layer 142.

[0149] In the above-described embodiments, a semiconductor or dielectric having a higher melting point than a metal or the like is exemplified as the material of the second nanoantenna 122. However, the material of the second nanoantenna 122 only needs to have a melting point at least higher than that of the first nanoantenna 112, and may be any material other than a metal, semiconductor, or dielectric having a melting point sufficiently higher than that of the metallic material of the first nanoantenna 112.

[0150] In the above embodiment, an example in which the light source device according to the present invention is mounted on a projector has been shown, but the present invention is not limited to this. The light source device according to the present invention can also be applied to lighting fixtures, automobile headlights, head-mounted displays, etc.

[0151] The light source device according to the aspect of the present invention may have the following configuration. A light source device according to one embodiment of the present invention includes a light source that emits excitation light, a phosphor that receives the excitation light and emits fluorescence having a wavelength different from the wavelength of the excitation light, a first nanoantenna group provided on the phosphor and having a plurality of first nanoantennas, and a second nanoantenna group provided on the phosphor and having a plurality of second nanoantennas, wherein each of the plurality of first nanoantennas is made of a metal, and each of the plurality of second nanoantennas is made of a material having a melting point higher than the melting point of the metal, and when viewed in a planar view from the normal direction of the phosphor, the arrangement area of ​​the second nanoantenna group overlaps with the irradiation area of ​​the excitation light, and the fluorescence is electric field-enhanced by each of the plurality of first nanoantennas and each of the plurality of second nanoantennas.

[0152] In a light source device according to one embodiment of the present invention, the arrangement region of the second nanoantenna group may be configured to be included within a region of the half-width of the power of the excitation light (or the transmitted light that passes through a phosphor excited by the excitation light).

[0153] In the light source device according to one embodiment of the present invention, the arrangement region of the second nanoantenna group has a power of (1 / e 2 ) may be included within the range of the value range.

[0154] In one embodiment of the light source device of the present invention, a base layer or a cover layer may be provided around each of the multiple first nanoantennas and each of the multiple second nanoantennas, the refractive index of the base layer and the refractive index of the cover layer may be lower than the refractive index of the second nanoantenna, and the spacing between the multiple first nanoantennas and the spacing between the multiple second nanoantennas may be determined so as to satisfy the Rayleigh anomaly condition in each of the first nanoantenna group and the second nanoantenna group.

[0155] In the light source device according to one aspect of the present invention, the base layer and the cover layer may have the same refractive index, and the spacing between the multiple first nanoantennas and the spacing between the multiple second nanoantennas may be the same.

[0156] In one embodiment of the light source device of the present invention, the maximum width of the multiple first nanoantennas in a planar view may be determined according to the conditions under which localized surface plasmon resonance occurs in the first nanoantenna group, and the maximum width of the multiple second nanoantennas in a planar view may be determined according to the conditions under which Mie resonance occurs in the second nanoantenna group.

[0157] In one embodiment of the light source device of the present invention, a transparent substrate that is transparent to excitation light and fluorescent light may be provided, and the phosphor, the first nanoantenna group, and the second nanoantenna group may be provided on the transparent substrate, and the first nanoantenna group and the second nanoantenna group may be disposed inside the phosphor.

[0158] In one embodiment of the light source device of the present invention, a third nanoantenna group may be provided on the opposite side of the transparent substrate in the thickness direction to the side on which the first nanoantenna group and the second nanoantenna group are arranged, the third nanoantenna group having a plurality of third nanoantennas, and the excitation light may be diffracted by the third nanoantenna group.

[0159] A projector according to one aspect of the invention may have the following configuration. A projector according to one aspect of the present invention comprises a light source device according to any of the above aspects of the present invention, a light modulation device that modulates light from the light source device in accordance with image information, and a projection optical device that projects the light modulated by the light modulation device.

[0160] A display device according to one aspect of the present invention may have the following configuration. A display device according to one aspect of the present invention includes the light source device according to the above aspect of the present invention. [Explanation of symbols]

[0161] 1...projector, 2, 2A, 2B...lighting device, 11, 12, 13...light source device, 21...semiconductor laser (light source), 34...phosphor, 111...first nanoantenna group, 112...first nanoantenna, 121...second nanoantenna group, 122...second nanoantenna, 140...fluorescent layer (phosphor), 141...base layer, 142...cover layer, BAR, BAQ...irradiation area, NAR...placement area, B1, BL, BL S ...Excitation light, YL...Fluorescence

Claims

1. A light source that emits excitation light; a phosphor that receives the excitation light and emits fluorescence having a wavelength different from the wavelength of the excitation light; A first nanoantenna group provided on the phosphor and having a plurality of first nanoantennas; A second nanoantenna group provided on the phosphor and having a plurality of second nanoantennas; Equipped with each of the plurality of first nanoantennas is made of a metal; each of the second nanoantennas is made of a material having a melting point higher than a melting point of the metal; In a plan view seen from a normal direction of the phosphor, an arrangement region of the second nanoantenna group overlaps with an irradiation region of the excitation light, the fluorescence is electric field enhanced by each of the first nanoantennas and each of the second nanoantennas; a base layer or a cover layer is provided around each of the first nanoantennas and around each of the second nanoantennas; the refractive index of the base layer and the refractive index of the cover layer are lower than the refractive index of the second nanoantenna; a distance between the first nanoantennas and a distance between the second nanoantennas are determined so as to satisfy a Rayleigh anomaly condition in each of the first nanoantenna group and the second nanoantenna group; Light source device.

2. The arrangement region of the second nanoantenna group is included at least within a region of a half-width of the power of the excitation light. The light source device according to claim 1 .

3. The arrangement region of the second nanoantenna group is included at least within a region of 1 / e2 value width of the power of the excitation light. The light source device according to claim 1 .

4. the refractive index of the base layer and the refractive index of the cover layer are equal to each other, The spacing between the first nanoantennas and the spacing between the second nanoantennas are equal to each other. The light source device according to claim 1 .

5. a maximum width of the plurality of first nanoantennas in a plan view is determined according to a condition under which localized surface plasmon resonance occurs in the first nanoantenna group, a maximum width of the second nanoantennas in a plan view is determined according to a condition in which Mie resonance occurs in the second nanoantenna group; The light source device according to claim 1 .

6. a transparent substrate that is transparent to the excitation light and the fluorescent light; the phosphor, the first nanoantenna group, and the second nanoantenna group are provided on the transparent substrate; the first nanoantenna group and the second nanoantenna group are disposed inside the phosphor; The light source device according to claim 1 .

7. a third nanoantenna group is provided on a side opposite to a side on which the first nanoantenna group and the second nanoantenna group are arranged in a thickness direction of the transparent substrate; the third nanoantenna group includes a plurality of third nanoantennas; The excitation light is diffracted by the third nanoantenna group. The light source device according to claim 6 .

8. An optical device according to any one of claims 1 to 7; a light modulation device that modulates the light from the light source device in accordance with image information; a projection optical device that projects the light modulated by the light modulation device; Equipped with projector.

Images