Light-emitting device

Abstract

The present invention provides a light-emitting device capable of producing a light beam with strong directivity. This light-emitting device comprises: a light source; a thin-film-shaped wavelength conversion body that has a light-receiving surface and a light-emitting surface, contains a dielectric material that converts incident light from the light-receiving surface into polariton component light and a fluorescent material that converts incident light from the light-receiving surface into dipole component light, and emits the polariton component light and dipole component light from the light-emitting surface; and a light-transmitting body having a plurality of structures that protrude from the light-emitting surface of the wavelength conversion body, are arranged along the light-emitting surface, and each have a columnar or upward-narrowed frustum-shaped side surface, each of the plurality of structures emitting the polariton component light and dipole component light.

Description

Light-emitting device

[0001] The present invention relates to a light emitting device including a wavelength conversion device having a wavelength conversion body that converts the wavelength of light.

[0002] Conventionally, a solid-state light source has been known that is a light-emitting device using a fluorescent molded body that emits light upon excitation by excitation light (see Patent Document 1). The fluorescent molded body has a first surface and a second surface that are arranged parallel to each other and opposite to each other, and a first inclined side surface and a second inclined side surface that are in contact with the first surface and inclined at an obtuse angle relative to the second surface. Patent Document 1 discloses a light-emitting device equipped with a laser light source that outputs excitation light to the fluorescent molded body. In this conventional light-emitting device, light emitted upon excitation at a light-emitting point (a focus of the excitation light output from the laser light source) located inside the fluorescent molded body is totally reflected by the first inclined surface and the second inclined surface, generating evanescent waves. The evanescent waves propagate along the first inclined surface and the second inclined surface, combine at the second surface, and are converted into propagating light.

[0003] International Publication No. WO2018 / 189998

[0004] The following are some examples of problems with conventional light-emitting devices: (1) The size of the shape of the fluorescent molding changes depending on the wavelength of the excited propagating light. Therefore, when there are multiple wavelengths of light to be extracted, it is difficult to control the extracted light using a fluorescent molding with a single-wavelength structure. (2) Because it is assumed that a laser light source with high temporal and spatial coherence is used as the excitation light source, the effect of using a surface-emitting light source is unknown. (3) Because the shape of the fluorescent molding is determined by the wavelength of the fluorescence (photoluminescence) emitted by excitation with laser light, the fluorescent molding has no control over the excitation light. (4) Because it is necessary to guide the laser light into the fluorescent molding using a laser light source or other optical system, it is difficult to realize a light-emitting device using a surface-emitting or diverging light source.

[0005] The present invention has been made in view of the above-mentioned points, and has as its object to provide a light emitting device that can obtain a luminous flux with strong directionality.

[0006] a light emitting device according to the present invention comprising: a light source; a thin-film wavelength converter disposed facing the light source; and a light-transmitting body disposed facing the wavelength converter, wherein the wavelength converter has a light-receiving surface facing the light source that receives primary light from the light source, a dielectric material that generates polariton component light from the primary light and a fluorescent material that generates dipole component light from the primary light, and a light-emitting surface opposite to the light source that emits the polariton component light and the dipole component light, and the light-transmitting body has a plurality of structures that protrude in a direction away from the light-emitting surface and are arranged along the light-emitting surface, and each of the structures has a columnar or upwardly tapered frustum-shaped side surface and a top surface that intersects with the side surface, and each of the plurality of structures receives the polariton component light and the dipole component light from the light-emitting surface, and combines and emits evanescent light generated by total reflection of the polariton component light and the dipole component light at the side surface at the top surface of each of the plurality of structures.

[0007] 1 is a schematic partial cross-sectional view showing the configuration of a light emitting device according to an embodiment; FIG. 2 is an enlarged schematic partial cross-sectional view showing the configuration of a light emitting device according to an embodiment; FIG. 3 is a schematic partial cross-sectional view showing the configuration of a modified light emitting device according to an embodiment; FIG. 4 is an enlarged schematic partial cross-sectional view showing a wavelength converter in a modified light emitting device according to an embodiment; FIG. 5 is an enlarged schematic partial cross-sectional view showing a fluorescent thin film of a wavelength converter in a modified light emitting device according to an embodiment; FIG. 6 is an enlarged schematic partial cross-sectional view showing a wavelength converter in a modified light emitting device according to an embodiment; FIG. 7 is an enlarged schematic partial cross-sectional view showing a fluorescent thin film of a wavelength converter in a modified light emitting device according to an embodiment; FIG. 8 is an enlarged schematic partial cross-sectional view explaining the operation of a structure of a wavelength converter in a light emitting device according to an embodiment; FIG. 9 is an enlarged schematic partial cross-sectional view showing the operation of a structure of a wavelength converter in a light emitting device according to an embodiment; FIG. 10 is an enlarged schematic partial cross-sectional view showing the configuration of a light emitting device according to an embodiment; FIG. 11 is a schematic perspective view showing a truncated cone structure of a wavelength converter according to an embodiment; FIG. 12 is a schematic perspective view showing a cylindrical structure of a wavelength converter according to an embodiment; FIG. 13 is a diagram showing an analysis range of an analytical model of a 2D electric field intensity simulation for a wavelength converter according to an embodiment; FIG. 14 is a diagram showing an analysis result of a 2D electric field intensity simulation for a wavelength converter according to an embodiment; FIG. 15 is a partial top view showing an arrangement of a plurality of structures of a wavelength converter according to an embodiment; FIG. 16 is a partial top view showing an arrangement of a plurality of structures of a modified wavelength converter according to an embodiment. FIG. 1 is a partial top view showing an arrangement of a plurality of structures in a modified example of a wavelength converter in an embodiment. FIG. 2 is a partial top view showing an arrangement of a plurality of structures in a modified example of a wavelength converter in an embodiment. FIG. 3 is a partial top view showing an arrangement of a plurality of structures in a modified example of a wavelength converter in an embodiment. FIG. 4 is a partial top view showing an arrangement of a plurality of structures in a modified example of a wavelength converter in an embodiment. FIG. 5 is a partial top view showing an arrangement of a plurality of structures in a modified example of a wavelength converter in an embodiment. FIG. 6 is a partial top view showing an arrangement of a plurality of structures in a modified example of a wavelength converter in an embodiment. FIG. 7 is a partial top view showing an arrangement of a plurality of structures in a modified example of a wavelength converter in an embodiment.FIG. 1 is a partial top view showing an arrangement of a plurality of structures in a modified example of a wavelength conversion device according to an embodiment. FIG. 2 is a schematic partial cross-sectional view showing the configuration of a modified example of a light emitting device according to an embodiment. FIG. 3 is a schematic partial cross-sectional view showing the configuration of a modified example of a light emitting device according to an embodiment. FIG. 4 is a schematic partial cross-sectional view showing the configuration of a modified example of a light emitting device according to an embodiment. FIG. 5 is a schematic partial cross-sectional view showing the configuration of a modified example of a light emitting device according to an embodiment. FIG. 6 is a diagram showing analysis results of an electric field intensity 3D simulation for a light emitting device according to a further embodiment. FIG. 7 is a schematic partial cross-sectional view of a light emitting device according to a further embodiment. FIG. 8 is a schematic partial cross-sectional view of a light emitting device according to a further embodiment. FIG. 9 is a schematic partial cross-sectional view of a light emitting device according to a further embodiment. FIG. 10 is a schematic partial top view of a light emitting device according to a further embodiment. FIG. 11 is a schematic partial cross-sectional view of a light emitting device according to a further embodiment. FIG. 12 is a schematic partial top view of a light emitting device according to a further embodiment. FIG. 13 is a schematic partial cross-sectional view of a light emitting device according to a further embodiment. 1 is a schematic cross-sectional view showing the configuration of a vehicle headlamp device of a lamp body equipped with a light emitting device of an embodiment as a light emitting module; FIG. 2 is a diagram showing a low-beam light distribution pattern formed on a virtual vertical screen by light irradiated forward from the vehicle headlamp device of a lamp body equipped with a light emitting device of an embodiment as a light emitting module; and FIG. 3 is a diagram showing a high-beam light distribution pattern formed on a virtual vertical screen by light irradiated forward from the vehicle headlamp device of a lamp body equipped with a light emitting device of an embodiment as a light emitting module.

[0008] Hereinafter, embodiments of the present invention will be described in detail.

[0009] 1 is a schematic partial cross-sectional view showing the configuration of a light-emitting device 11 according to an embodiment. In the following figures, optical components and the like are shown as rectangles, but their actual shapes are not shown, but are merely shown conceptually, and hatching in the cross-sectional views is omitted. The optical axis of the light-emitting device 11 is directed upward in FIG. 1 (the normal direction of the top surfaces of the light source 12 and the wavelength conversion device 13).

[0010] 1, the light emitting device 11 includes a light source 12 and a wavelength conversion device 13 that receives light from the light source 12. The light source 12 emits primary light L1, which is excitation light in a predetermined wavelength range, to the wavelength conversion device 13.

[0011] (Light Source) The light source 12 is a semiconductor light-emitting element that generates primary light L1 (blue light) having a peak wavelength in the range of 380 to 490 nm by applying a voltage in the forward direction. The light source 12 may be, for example, a light-emitting diode (LED: Light Emitting Diode) having a surface-emitting portion that emits the primary light L1, or a semiconductor laser diode (LD: Laser Diode) having a resonator structure. Examples of semiconductor lasers that are light-emitting elements of the light source 12 include vertical cavity surface-emitting lasers (VCSELs: Vertical Cavity Surface Emitting Lasers) and photonic crystal surface-emitting lasers (PCSELs) having a surface-emitting portion, as well as edge-emitting lasers (EELs) made of InGaN-based semiconductors.

[0012] (Wavelength conversion device) The wavelength conversion device 13 has a plate-shaped (thin film-shaped) wavelength conversion body 14 having a light receiving surface S1 facing the light source 12 and a light emitting surface S2 opposite the light source 12 and having the optical axis of the light source 12 as its normal, and a light-transmitting body 16 having a plurality of structures 15 bonded to the light emitting surface S2 and arranged in parallel.

[0013] (Wavelength converter) The wavelength converter 14 contains a fluorescent material (which is also a dielectric) and has a secondary light source function of receiving the primary light L1 from the light source 12 on the light-receiving surface S1, converting the wavelength of part of the primary light L1, and emitting it to the translucent body 16 having the structure 15.

[0014] The wavelength converter 14 converts the wavelength of the primary light L1 into polariton component light L1a and dipole-polariton mixed light L2, which will be described later. The wavelength converter 14 emits illumination light L3 containing the polariton component light L1a and the dipole-polariton mixed light L2 from the light exit surface S2 to the transparent body 16, and emits the illumination light L3 from the structure 15 of the transparent body 16 to the outside.

[0015] (Polariton component light) When the primary light L1 propagates through a dielectric, the electric field of the primary light causes a charge imbalance, i.e., polarization, within the dielectric. In a solid dielectric, this is electronic polarization formed by the electrons and nuclei within atoms. The primary light propagates through the dielectric while causing polarization. The charge pairs (electric dipoles) created by polarization oscillate in response to the electric field oscillation of the primary light. In a dielectric, the resonant angular frequency of the electric dipole oscillation formed by electronic polarization is in the ultraviolet light region, and in the visible light region, which is sufficiently far from the resonant angular frequency on the low angular frequency side, the electric dipole oscillates in response in approximately the same phase as the electric field oscillation of the incident primary light.

[0016] In an electric dipole vibrating due to the AC electric field of the primary light L1, the acceleration of the charge constantly changes, resulting in the electric dipole emitting electromagnetic waves (secondary light) of the same frequency. The electric dipole radiation radiates in a donut-shaped intensity pattern centered on the dipole, but because it overlaps with radiation from the primary light coming from behind, a large forward-scattered component propagates (this resonance state is called a polariton). The emission process of this electric dipole radiation is accompanied by a 90° phase delay of the oscillation. As a result, in the visible light range, the electric dipole responds almost in phase with the electric field oscillation of the incident primary light (the phase delay is almost 0°) and emits secondary light with a 90° phase delay. This causes a phase delay in the transmitted light (here, also referred to as polariton component light), which is a combination of the incident primary light and the electric dipole radiation. The delayed transmitted light becomes the incident light for the next electric dipole it encounters, resulting in a progressive delay of the transmitted light each time it encounters an atom. The refractive index of a dielectric is defined as the rate at which the propagation speed v of transmitted light for each wavelength slows down relative to the speed of light c in a vacuum, expressed as the speed ratio n = c / v. The higher the dielectric constant ε and the more easily polarized a dielectric is, the higher the refractive index and the slower the propagation speed of light in the dielectric.

[0017] (Dipole Component Light) Fluorescence in fluorescent materials is light emission caused by primary light L1, which excites the fluorescent material atoms. Before becoming excited, the electron configuration of the fluorescent material atoms (also called luminescence centers) is in the ground state. Absorption of primary light raises the atoms to an electronically excited state, and the excited electrons lose some of their vibrational energy, returning to a stable ground state with the emission of a photon. When the excited electrons return to the ground state, they emit secondary light (fluorescence) with lower energy corresponding to a longer wavelength than the absorbed primary light. That is, when light is irradiated onto a fluorescent material, the fluorescent material atoms absorb light polarized in the direction along their transition dipole moment and are deactivated by emitting light polarized in the direction of the transition dipole moment. When excited from the ground state to the excited state, the transition dipole moments of absorption and emission are parallel, so that stationary atoms emit fluorescence (herein also referred to as dipole component light) polarized in the same direction as the incident primary light. When electrons move from an excited state to a ground state, there is a loss of vibrational energy. Therefore, the wavelength of the fluorescence spectrum is inversely proportional to the radiation energy, and the wavelength of the fluorescence spectrum is longer than the excitation spectrum of the primary light due to the energy loss (Stokes' law). Fluorescence continues while the excitation primary light is illuminating the fluorescent material. It stops when the irradiation of the excitation light stops. For example, YAG (Y ３ Al ５ O １２ When Ce atoms substitute for Y sites inside a Ce (Ce) crystal, they act as a luminescent center, absorbing short-wavelength light (300 nm to 500 nm) and emitting new yellow (500 nm to 700 nm) long-wavelength fluorescence (dipole component light).

[0018] As described above, the wavelength converter 14 having the light-receiving surface S1 and the light-emitting surface S2 includes a dielectric material that converts the primary light L1 of the incident light from the light-receiving surface S1 into polariton component light L1a and a fluorescent material that generates dipole component light from the incident light from the light-receiving surface S1, and emits the polariton component light L1a and the dipole component light from the light-emitting surface S2. Note that in practice, the dipole component light generates polariton component light (i.e., dipole component optically induced polariton component light) due to scattering in the medium. In the following description, the dipole component light and the dipole component optically induced polariton component light will be collectively referred to as dipole-polariton mixed light L2.

[0019] The fluorescent material is, for example, Y ３ Al ５ O １２ In addition to Ce, yellow phosphors such as ZnS:Mn and Lu ３ Al ５ O １２ : Ce, BaMg ２ Al １６ O ２７ Green phosphors such as CaS:Eu, Mn, and red phosphors such as CaS:Eu, CASN, and SCASN can be used.

[0020] The fluorescent material contained in the wavelength converter 14 may be any material, including quantum dot fluorescent materials, or fluorescent material particles. The fluorescent material particles do not necessarily have to have a uniform particle size. Quantum dot fluorescent materials include semiconductor quantum dots (e.g., InP / ZnS quantum dots) and perovskite quantum dots, such as complex halide perovskite CsPb(Cl / Br). ３ , CsPbBr ３ , CsPb(Br / I) ３ , CsPbI ３ etc. are used.

[0021] The thickness of the wavelength converter 14 is preferably 500 nm to 50 μm, more preferably 500 nm to 10 μm, and even more preferably 500 nm to 2000 nm.

[0022] The operation of the wavelength converter 14 will be explained with reference to FIG. 2, which is an enlarged schematic partial cross-sectional view of FIG. 1. ２ O ３ Fluorescent material particles Y uniformly dispersed in the ３ Al ５ O １２In the wavelength converter 14, which is a ceramic plate containing Ce garnet crystal powder YAG, for example, blue light (polariton component light L1a) is scattered at the YAG / alumina interface at a first point, blue light (primary light L1) is absorbed by the YAG at a second point and converted into yellow fluorescence (dipole component of dipole-polariton mixed light L2), and the fluorescence (polariton component of dipole-polariton mixed light L2) is scattered at a third point at the YAG / alumina interface, each of which serves as a light-emitting point. In this way, the wavelength converter 14 functions as a secondary light source.

[0023] 3, as a modified example, the wavelength converter 14 may have a structure including a fluorescent thin film 14B and a light-transmitting material part 14C that contacts and supports the light-receiving surface S1. It is preferable that the light-transmitting material part 14C is disposed on the light source 12 side so that the fluorescent thin film 14B side becomes the light-emitting surface S2. Optical glass or a sapphire plate can be used for the light-transmitting material part 14C, which is the substrate.

[0024] The refractive index of the light-transmitting material part 14C is preferably equal to or less than that of the wavelength converter 14. A sapphire (alumina) plate having a similar refractive index and high thermal conductivity is preferable as the light-transmitting material part 14C, or a YAG substrate not doped with Ce, the luminescence center, may be used. The YAG substrate is preferable because it has a thermal expansion coefficient that is almost the same as that of the wavelength converter 14 (YAG:Ce), and therefore there is little possibility that the wavelength converter 14 and the light-transmitting material part 14C will peel off during high-temperature operation.

[0025] The fluorescent thin film 14B is formed directly on one surface of the light-transmitting material portion 14C with a thickness of at least 500 nm (to obtain the dipole-polariton mixed light L2). The fluorescent thin film 14B may include, for example, particulate fluorescent material (fluorescent material particles) and a binder that adheres the fluorescent material particles. Alternatively, the fluorescent thin film 14B may be formed by applying a fluorescent thin film raw material containing the fluorescent material and binder to one surface of the light-transmitting material portion 14C and reacting the raw material at room temperature or by heat treatment at a temperature of 2000°C or less. Examples of application methods include printing, spraying, drawing using a dispenser, and inkjet printing.

[0026] The fluorescent material is selected depending on the type of emission wavelength of the light source 12. One or more types of fluorescent material particles are used as the fluorescent material, and when multiple types are used, they may be mixed and used, or multiple layers may be laminated to form the fluorescent thin film 14B.

[0027] Furthermore, the wavelength converter 14 may be in the form of a plate made of a single crystal of a fluorescent material, a single-phase ceramic of a fluorescent material, or a dielectric ceramic containing fluorescent material particles, without using a substrate. For example, as shown in FIG. 4A, the wavelength converter 14 may be made of alumina Al, a dielectric material. ２ O ３ 4B, the fluorescent thin film 14B may be in the form of a ceramic plate having fluorescent material particles YAG uniformly and densely dispersed therein. ２ O ３ As shown in FIG. 5A, the wavelength converter 14 may be provided on a substrate having nano-particle fluorescent material particles of YAG uniformly and densely dispersed therein. ２ O ３ 5B, the fluorescent thin film 14B may be a ceramic plate containing quantum dot phosphors QDs uniformly and densely dispersed therein. ２ O ３ The fluorescent material may be provided on a substrate with quantum dot phosphors QDs dispersed uniformly and densely in the nanoparticles. Note that the particle diameters of these fluorescent material particles do not necessarily have to be uniform according to the fluorescent wavelength.

[0028] In this way, the wavelength converter 14 has a light receiving surface S1 and a light emitting surface S2, and includes a dielectric material that converts incident light from the light receiving surface S1 into polariton component light and a fluorescent material that converts incident light from the light receiving surface S1 into dipole component light, and has a structure that emits the polariton component light and dipole component light from the light emitting surface S2.

[0029] (Structures) The multiple structures 15 formed on the light emission side of the light-transmitting body 16 protrude above the light emission surface S2 of the wavelength converter 14, are arranged at a predetermined interval along the light emission surface S2, and each has a columnar or frustum-shaped side surface FS that tapers upward. Each of the structures 15 emits polariton component light and dipole component light. Each of the structures 15 of the light-transmitting body 16 controls the narrow-angle light distribution characteristics of the illumination light L3 emitted from the wavelength converter 14.

[0030] The light-transmitting body 16 integrally includes a light-transmitting support layer 15B having a thickness of 300 nm or less, sandwiched between the structure 15 and the wavelength converter 14. The light-transmitting support layer 15B enables the formation of multiple structures 15 by nanoimprinting. The light-transmitting material forming the light-transmitting body 16 is an organic compound resin such as an MS resin or SAN resin copolymerized with PMMA (polymethyl methacrylate), PC (polycarbonate), and PS (polystyrene), diethylene glycol bisallyl carbonate, transparent silicone resin, or UV-curable resin. The light-transmitting material forming the light-transmitting body 16 may also be an inorganic transparent dielectric such as ceramics, glass, or sapphire. The light-transmitting material forming the light-transmitting body 16 is selected from those having a refractive index in the range of 1.30 to 2.50 for light with a wavelength of 550 nm. The material of the light-transmitting body 16 is also a dielectric, and therefore has the function of receiving the primary light L1 and polariton component light L1a from the light source 12 and emitting the polariton component light L1a.

[0031] Each side surface FS of the structure 15 is inclined at an angle (taper angle) of 40 to 90 degrees from the light emission surface S2 of the wavelength converter 14, and has a top surface FT that intersects with the side surface FS at an obtuse angle. The height from the bottom surface of the structure 15 (the plane passing through the lower end of the side surface FS) to the top surface FT is 250 to 2000 nm.

[0032] The width of each top surface FT of the structure 15, which is parallel to the light emitting surface S2 of the wavelength converter 14, is 300 to 2000 nm.

[0033] The operation of the structure 15 will be described with reference to FIGS. 6 and 7 , which are enlarged schematic cross-sectional views of the structure 15 shown in FIG. 1 . In this embodiment, multi-wavelength light is irradiated obliquely onto the inner surface of the side surface FS of the structure 15, and the multi-wavelength light is totally reflected (irradiated at an angle of incidence greater than the critical angle) at the interface of the side surface FS. When the multi-wavelength light is totally reflected at the interface in this manner, a Gooss-Henschen shift occurs in one ray L of the multi-wavelength light between the incident point O at the interface of the side surface FS and the exit point R of the reflected light, as shown in FIG. 6 . This Gooss-Henschen shift occurs when the light totally reflected at the interface seeps out beyond the interface (into space, i.e., outside the structure 15) and generates evanescent light that is trapped near the interface, as shown by the dashed line in FIG. 6 .

[0034] When light rays L are continuously irradiated from an inward oblique direction onto the side surface FS of the structure 15 and are totally reflected, evanescent waves extend from the space-side surface toward the center of the top surface FT, combine with evanescent waves extending from the opposite side to form a traveling wave, and are extracted to the outside of the structure as illumination light.

[0035] 7, the evanescent optical field exists at the interface of the side surface FS, and the tail of the optical field reaches the center of the top surface FT of the structure 15. Therefore, according to this embodiment, the polariton component light L1a and the dipole-polariton mixed light L2 generate evanescent wave coupling near the upper interface of the top surface FT, and can be emitted strongly from the top surface of the structure 15.

[0036] As a result of this evanescent electric field coupling, the polariton component light L1a and the dipole-polariton mixed light L2 have narrow-angle light distribution characteristics (low etendue) and are emitted from the structure 15. That is, the columnar or frustum-shaped structure 15 has the function of narrowing the emission direction of the polariton component light L1a and the dipole-polariton mixed light L2 in the wavelength converter 14 and at the same time improving the light extraction efficiency of the polariton component light L1a and the dipole-polariton mixed light L2.

[0037] The extraction efficiency of evanescent light depends on the distance between each structure 15 and the light-emitting point of the dielectric material and fluorescent material of the wavelength converter 14. This is because, for example, as shown in Fig. 8, when the light-emitting point (scattering point or generation point) (p1) of blue light that realizes a pseudo-white narrow-angle light source is farther from the frustum-shaped structure 15 than the light-emitting point (p2), the spatial angle (k1) formed by the light-emitting point (p1) with respect to the side surface FS of the structure 15 becomes smaller than the spatial angle (k2) formed by the light-emitting point (p2), and the effect of the light-emitting point (p1) also weakens.

[0038] However, in this embodiment, since the light emitting surface S2 of the wavelength converter 14 is only 300 nm or less away from the structure 15 (because the translucent support layer 15B has a thickness of 300 nm or less), the coupling effect due to the distance between the light emitting point of the wavelength converter 14 and each structure 15 is large.

[0039] As described above, according to this embodiment, the primary light L1 emitted from the light source 12 excites the polariton component light L1a and the dipole-polariton mixed light L2 in the wavelength converter 14, and the secondary lights emitted by different mechanisms are totally reflected by the multiple structures 15 (side surfaces FS) of the same shape, so that the illumination light L3 emitted from the top surface F of the structure 15 is extracted as highly directional narrow-angle light, as shown in Fig. 8. Therefore, a narrow-angle emission effect can be obtained for the surface emission and multi-wavelength (broadband light waves) of the light source 12.

[0040] Specifically, Fig. 9 shows a truncated cone structure 15 having a truncated cone-shaped side surface FS (taper angle Θ = 40 degrees) that tapers upward. Fig. 10 shows a cylindrical structure 15 having a cylindrical side surface FS (taper angle Θ = 90 degrees). These truncated cone and cylindrical structures 15 have a width φbottom (diameter) of a bottom surface FB on the light emission surface S2 side of the wavelength converter 14, a width φtop (diameter) of a top surface FT parallel to the bottom surface, and a height h from the bottom surface to the top surface FT.

[0041] (Examples and Comparative Tests) Since the size of the structure 15 varies depending on the refractive index n of the material that forms it, examples and comparative tests were carried out to confirm the effects thereof.

[0042] The refractive index n of the material forming the truncated cone-shaped single structure was changed, and various structure samples of different sizes were fabricated while fixing the taper angle of the side surface FS. Based on the simulation results, the optimum size range of the structure was determined.

[0043] Table 1 below shows the size specifications of five structure samples I to V (width φtop of top surface FT, width φbottom of bottom surface, height h, and taper angle Θ).

[0044] The multi-wavelength light extraction effect in the single structure 15 was verified using a 2D electric field intensity simulation by keyFDTD from Science and Technology Research Institute Co., Ltd.

[0045] Fig. 11 shows the analysis range of the analytical model for the electric field intensity 2D simulation. Fig. 12 shows the results of the electric field intensity 2D simulation, which shows the extraction effect of three emission wavelengths Λ (450 nm / 560 nm / 610 nm) in a single structure of the structure sample IV in Table 1 as an example. Although there are some differences in narrow-angle emission (electric field intensity) depending on the emission wavelength Λ in the structure sample IV, it was confirmed that the structure sample IV can control multiple wavelengths with a single structure.

[0046] It was confirmed that narrow-angle light distribution characteristics of illumination light L3 can be obtained even with an emission point located outside (300 nm deep below the base) rather than inside structure 15, as in structure sample IV. This shows that yellow light (dipole-polariton mixed light L2) and blue light (polariton component light L1a) are mixed, and illumination light L3 that is visually recognized as white light is output.

[0047] Tables 2 and 3 below show the range of suitable structure sizes and the range of more suitable structure sizes determined based on the results of the above-mentioned comparative tests of structure samples in which the taper angle Θ of the side surface FS of the structure 15 was changed.

[0048]

[0049] In Example 1, the device structure shown in FIG. 3 was adopted, and alumina Al, a dielectric material shown in FIG. 4B, was used. ２ O３ A wavelength converter 14 having fluorescent thin films 14B of various thicknesses, each having nano-particle fluorescent material particles YAG (yellow phosphor) uniformly and densely dispersed therein, on a transparent transmissive substrate (light-transmitting material portion 14C), was combined with a blue-emitting LED to produce a number of light-emitting devices 11 in which a number of truncated cone structures 15 (see Figure 9) were formed on the fluorescent thin films 14B using transparent resin (refractive index n = 1.4).

[0050] When the light source 12 was a blue-emitting LED having an emission spectrum with a peak wavelength in the range of 380 to 490 nm and combined with the wavelength converter 14 to form a white light source, the intensity ratio of the polariton component light L1a to the dipole-polariton mixed light L2 in the white light from this light source was approximately 1:2. This ratio can be changed by changing the thickness of the wavelength converter 14, and is preferably 1:1 to 1:3.

[0051] The light emitting device 11 functions as a multi-wavelength narrow-angle white light source having an emission spectrum with two peak wavelengths in the range of 380 to 780 nm, in which the polariton component light L1a and the dipole-polariton mixed light L2 are combined.

[0052] The polariton component light L1a has an emission spectrum with a peak wavelength λ1 within a range of 380 to 490 nm, and the dipole-polariton mixed light L2 has an emission spectrum with a peak wavelength λ2 within a range of 490 to 780 nm.

[0053] The peak wavelength λ1 and the peak wavelength λ2 in the emission spectrum were separated by 50 nm or more.

[0054] The plurality of truncated cone structures 15 were arranged in a close-packed manner as shown in FIG.

[0055] In the light emitting device of Example 1, each truncated cone structure 15 was set to the size specifications of structure sample I shown in Table 1 above.

[0056] For example, a visual light emission comparison test showed that when the distance between the bottom surface of the structure 15 and the fluorescent thin film 14B is about 0.3 μm, the thickness of the fluorescent thin film 14B is preferably about 0.5 to 2 μm. It was also found that it is preferable for the multiple structures 15 to have similar structure heights h.

[0057] According to the above embodiments and examples, the primary light emitted from the light source 12 becomes dipole-polariton mixed light L2 and polariton component light L1a in the wavelength converter 14, and acts on each structure 15, thereby realizing a narrow-angle light source for a wide range of component light wavelengths.

[0058] 14 shows a schematic top view of a light-emitting device 11 according to another modification, as viewed from the optical axis direction. This modification is the same as Example 1, except that it has a plurality of cylindrical structures 15 instead of the truncated cone structure 15.

[0059] 15 is a schematic top view of a light-emitting device 11 according to another modification, as viewed from the optical axis direction. This modification is the same as Example 1, except that it has a plurality of triangular pyramid structures 15 instead of the truncated cone structures 15.

[0060] 16 shows a schematic top view of a light-emitting device 11 according to another modification, as viewed from the optical axis direction. This modification is the same as Example 1, except that it has a plurality of triangular prism structures 15 instead of the truncated cone structures 15, and there is a gap between each structure that is greater than 0 and not greater than 200 nm.

[0061] 17 is a schematic top view of a light-emitting device 11 according to another modification, as viewed from the optical axis direction. This modification is the same as Example 1, except that it has a plurality of truncated quadrangular pyramid structures 15 instead of the truncated cone structures 15.

[0062] 18 shows a schematic top view of a light-emitting device 11 according to another modification, as viewed from the optical axis direction. This modification is the same as Example 1, except that it has a plurality of square pillar structures 15 instead of the truncated cone structures 15, and there is a gap between each structure that is greater than 0 and not greater than 200 nm.

[0063] 19 is a schematic top view of a light-emitting device 11 according to another modification, as viewed from the optical axis direction. This modification is the same as Example 1, except that it has a plurality of hexagonal pyramid structures 15 instead of the truncated cone structures 15.

[0064] 20 shows a schematic top view of a light-emitting device 11 according to another modification, as viewed from the optical axis direction. This modification is the same as Example 1, except that it has a plurality of hexagonal pillar structures 15 instead of the truncated cone structures 15, and there is a gap between each structure that is greater than 0 and not greater than 200 nm.

[0065] 21 shows a schematic top view of a light-emitting device 11 according to another modification, as viewed from the optical axis direction. This modification is the same as the above-described Example 1, except that the truncated cone structures 15 are not arranged in a close-packed manner, but rather a plurality of truncated cone structures 15 are arranged in a matrix (row and column).

[0066] 22 shows a schematic top view of a light-emitting device 11 according to another modification, as viewed from the optical axis direction. This modification is the same as the modification shown in FIG. 21, except that it has a plurality of cylindrical columnar structures 15 instead of the truncated cone structures 15.

[0067] 23 shows a schematic top view of a light-emitting device 11 according to another modification, as viewed from the optical axis direction. This modification is the same as the above-described Example 1, except that the truncated cone structures 15 are not arranged in a close-packed manner, but rather a plurality of truncated cone structures 15 are arranged at a period (structure period) greater than the predetermined pitch of the above-described Example 1.

[0068] 24 shows a schematic top view of a light-emitting device 11 according to another modification, as viewed from the optical axis direction. This modification is the same as the modification shown in FIG. 23, except that it has a plurality of cylindrical columnar structures 15 instead of the truncated cone structures 15.

[0069] FIG. 25 shows a schematic partial cross-sectional view of a light-emitting device 11 according to another modification. This modification includes a large number of microcavities arranged periodically or randomly throughout the entire light-transmitting support layer 15B below the structure 15 of the light-transmitting body 16. This modification is the same as the embodiment shown in FIG. 1 except that these microcavities suppress multiple reflections within the wavelength converter 14 and adjust the ratio of polariton component light to dipole component light. The microcavity region is a void such as a tiny air layer, and controls to increase the scattering of blue light of the polariton component light L1a. The microcavity region may be a void or particles with different refractive indices, i.e., particles of a low refractive index material and a high refractive index material, or a stack of low refractive index material layers and high refractive index material layers.

[0070] 26 is a schematic partial cross-sectional view of another modified light-emitting device 11. This modified example is the same as the embodiment shown in FIG. 1 except that multiple reflections within the wavelength converter 14 are suppressed by periodically or randomly including a large number of microcavities on the transparent body 16 side of the main body within the wavelength converter 14, and the ratio of polariton component light to dipole component light is adjusted.

[0071] 27 is a schematic partial cross-sectional view of another modified light-emitting device 11. This modified example is the same as the embodiment shown in FIG. 1 except that multiple reflections within the wavelength converter 14 are suppressed by periodically or randomly including a large number of microcavities at the interface between the wavelength converter 14 and the light-transmitting support layer 15B below the structure 15 of the light-transmitting body 16, thereby adjusting the ratio of polariton component light to dipole component light.

[0072] Fig. 28 shows a schematic partial cross-sectional view of a light-emitting device 11 according to another modification. This modification is the same as the embodiment shown in Fig. 3, except that the wavelength converter 13 and the vertical-cavity surface-emitting laser (VCSEL) of the light source 12 are held with a space between them, and a scattering layer is attached to the wavelength converter 14 on the light source 12 side to scatter the primary laser light.

[0073] Fig. 29 shows a schematic partial cross-sectional view of a light-emitting device 11 according to another modification. This modification is the same as the embodiment shown in Fig. 3, except that the wavelength converter 13 and the semiconductor laser of the light source 12 are held with a space between them, a scattering layer is attached to the wavelength converter 14 on the light source 12 side, and primary laser light of a divided semiconductor laser array or the like as the light source 12 is scattered. In this case, the divided semiconductor laser of the light source 12 is a light source 12 array consisting of an array of multiple light-emitting elements, each of which emits incident light toward a respective one or group of structures 15.

[0074] (Further Embodiments) The wavelength conversion devices of the above-described embodiments and modifications use a wavelength converter 14 that includes a thin-film wavelength converter 14 that emits polariton component light L1a and dipole component light L2, and a light-transmitting body 16 that has a plurality of structures 15 that are arranged to protrude from the wavelength converter 14 and each have a columnar or upwardly tapered frustum-shaped side surface, and each of the plurality of structures 15 emits polariton component light L1a and dipole component light L2. That is, in the above-described embodiments and modifications, the thin-film wavelength converters 14 that emit polariton component light L1a and dipole component light L2 are uniformly (over the entire surface) arranged below the plurality of arranged structures 15.

[0075] In the wavelength converter 13 of the above embodiment and modified example, the thickness of the wavelength converter 14 is specified on the assumption that the efficiency of coupling evanescent light and converting it into propagating light depends on the distance between the structure 15 and the light-emitting point (the vertical distance between the center line of the structure). However, the narrowing angle can be further improved by taking into consideration the lateral position of the light-emitting point relative to the structure.

[0076] In the above embodiment, the wavelength converter 14 around the structure 15 includes both light emitting points that contribute to narrowing the angle and light emitting points that do not contribute to narrowing the angle.

[0077] Therefore, a 3D simulation of the electric field intensity due to the lateral displacement of the light-emitting point in the wavelength converter 14 was performed. Figure 30 shows the results of a 3D simulation of the electric field intensity, which demonstrates the extraction effect of an emission wavelength of 560 nm, in a model in which the analytical model of the 2D electric field intensity simulation shown in Figure 11 is expanded to a 3D model of three structures 15 in the close-packed arrangement shown in Figure 13, with the structures 15 being the truncated cones of structure sample IV in Table 1 above. As shown in Figure 30, it was confirmed that the lateral displacement of the light-emitting point in structure sample IV (in Figure 30, the position of the light-emitting point on the center line of the structure 15, the position to the right of the center line, and the position between adjacent structures 15) results in differences in the angle of the radiation direction of narrow-angle light emission (electric field intensity). As is clear from Figure 30, the best narrow-angle light emission is obtained when the light-emitting point is located on (or near) the center line of the structure 15.

[0078] Therefore, in a further embodiment, a light-shielding layer SK is provided on the light emission surface S2 (light extraction surface) of the wavelength converter 14, and an opening KK is provided in the light-shielding layer SK only in the center below the top surface FT of each truncated cone structure 15 (Figure 31).

[0079] 31 shows a schematic partial cross-sectional view of a light-emitting device 11 according to a further embodiment. The light-emitting device 11 according to this further embodiment is the same as the embodiment shown in FIG. 1 except that a light-shielding layer SK is disposed between the wavelength converter 14 and the transparent body 16. The light-shielding layer SK is arranged coaxially with the center lines of the top surfaces FT of the plurality of structures 15 and has a plurality of openings KK for emitting the polariton component light L1a and the dipole component light L2. That is, in a wavelength converter 13 according to a further embodiment, a light-shielding layer SK is disposed between the wavelength converter 14 and the transparent body 16. The light-shielding layer SK has a plurality of openings KK that are arranged so as to overlap with the top surfaces FT of the plurality of structures 15 in a top view.

[0080] In the light emitting device 11 according to a further embodiment, light from a light emitting point (p3) that is far from the center below the top surface FT of the truncated conical structure 15 and that does not contribute much to the narrow angle is blocked by the light blocking layer SK, and it is possible to selectively extract only light from light emitting points (p4, p5) near the center below the top surface FT of the truncated conical structure 15 that contribute greatly to the narrow angle. The closer the light emitting point is to the central axis directly below the top surface FT of the truncated conical structure 15, the more it contributes to the narrow angle, and the farther it is from the central axis, the less it contributes.

[0081] Therefore, since the light-emitting point is dependent on the lateral position, the wavelength converter 13 preferably has the wavelength converter structure as shown in (1) to (4) below in order to enhance the narrow angle.

[0082] (1) The wavelength converter 13 has a light-shielding layer SK on the light-emitting surface of the wavelength converter 14, and the light-shielding layer SK has openings KK arranged in the same manner as the structures 15, the openings KK being provided directly below the structures 15 and sharing the same central axis, and the structures 15 being provided directly above the openings KK. According to this wavelength converter 13, by arranging the light-shielding layer SK in a location other than the center directly below the structures 15, it is possible to efficiently extract light from light-emitting points that have a large effect on narrow angle.

[0083] (2) It is preferable that the light-shielding layer SK has little absorption of the polariton component light L1a and the dipole component light L2 (380 to 780 nm), and is preferably a light-reflecting film such as a metal mirror, a dielectric multilayer mirror, or both. In this case, the reflected light components are repeatedly reflected and scattered to different light-emitting positions, and are then emitted from the opening KK.

[0084] The light-shielding layer SK includes a metal mirror or a dielectric multilayer mirror, and suppresses absorption of and reflects the polariton component light L1a and the dipole component light L2. The upper limit of the thickness of the light-shielding layer SK is preferably 5 μm or less for the sake of forming the opening KK. On the other hand, the lower limit of the thickness of the light-shielding layer SK is preferably 5 nm or more, so that the layer can have a light-shielding function.

[0085] (3) A phosphor (wavelength converter 14) may be disposed so as to contact the opening KK of the light-shielding layer SK. An example of this modification is shown in FIG. 31 . FIG. 31 is a schematic partial cross-sectional view showing the configuration of a modification of the light-emitting device 11 according to a further embodiment. The light-transmitting body 16 of the wavelength converter 13 shown in FIG. 31 integrally includes a light-transmitting support layer 15B sandwiched between the structure 15 and the wavelength converter 14. Therefore, in terms of the vertical position of the light-shielding layer SK, the lower surface of the light-shielding layer SK is formed coplanar (in the same plane or coplanar) with the lower surface of the light-transmitting support layer 15B and is in contact with the wavelength converter 14. This results in a wavelength converter 13 having a wavelength converter 14 containing a fluorescent material in the opening KK of the light-shielding layer SK. In this case, the portion of the light-transmitting support layer 15B above the light-shielding layer SK is formed to have a thickness of 300 nm or less.

[0086] This other modification is shown in Fig. 32. Fig. 32 is a schematic partial cross-sectional view showing the configuration of a modification of the light-emitting device 11 according to a further embodiment. Regarding the vertical position of the light-shielding layer SK of the light-emitting device 11, the upper surface of the light-shielding layer SK is formed as a coplanar (same plane or coplanar) with the upper surface of the wavelength converter 14, and is in contact with the light-transmitting body 16 (light-transmitting support layer 15B).

[0087] Yet another modification is shown in FIG. 33 . FIG. 33 is a schematic partial cross-sectional view illustrating the configuration of a modification of the light-emitting device 11 according to a further embodiment. The modification shown in FIG. 33 is identical to the light-emitting device 11 shown in FIG. 3 , except that a fluorescent thin film 14B is provided on a light-transmitting material portion 14C, filling the openings KK, and a light-shielding layer SK is provided. This modification results in a wavelength conversion device 13 containing fluorescent material only in the openings KK of the light-shielding layer SK. In this case, to fill the openings KK of the light-shielding layer SK with fluorescent material, for example, a resin or ink containing fluorescent material can be applied to the light-transmitting material portion 14C provided with the light-shielding layer SK in the opening KK pattern, and then the openings KK can be filled by pressing a squeegee or the like (so-called screen printing). Furthermore, if excess fluorescent material adhering to the light-shielding layer SK is unnecessary, the unnecessary fluorescent material can be removed by polishing or the like.

[0088] (4) A suitable size of the opening KK of the light-shielding layer SK in the wavelength conversion device 13 of the light-emitting device 11 is set.

[0089] Fig. 34 is a schematic partial cross-sectional view showing a modified wavelength converter 13 in a further embodiment, in which the inner edge of the opening KK of the light-shielding layer SK is located near the outer edge of the bottom surface FB of each of the three structures 15. Fig. 35 is a partial top view showing the arrangement of the three structures 15 of the modified wavelength converter 13 corresponding to Fig. 34 .

[0090] 34 and 35 , the size Kd of the openings KK of the light-shielding layer SK in the wavelength conversion device 13 of the light-emitting device 11 is preferably equal to or smaller than the size Bd of the bottom surface FB of the structure 15. Each of the multiple openings KK of the light-shielding layer SK has an opening area equal to or smaller than the area of ​​the bottom surface of the structure 15. That is, each of the multiple openings KK of the light-shielding layer SK overlaps with or is formed inside the outer edges of the bottom surfaces FB of the multiple structures 15 in a top view. Note that FIGS. 34 and 35 show the case where the openings KK of the light-shielding layer SK of the light-emitting device 11 are formed near and inside the outer edges of the bottom surfaces FB of the structures 15 (Kd<Bd).

[0091] Figure 36 shows the light distribution characteristics of the radiated light emitted from the top surface FT of one structure 15 in the light-emitting device 11 shown in Figure 35 when the structure 15 is a truncated cone of structure sample IV in Table 1 above, and the size Kd of the opening KK matches the size Bd of the bottom surface FB of the structure 15 (Kd = Bd).

[0092] Fig. 37 is a schematic partial cross-sectional view showing another modified example of the wavelength converter 13 in a further embodiment, in which the inner edge of the opening KK of the light-shielding layer SK is located near the center line of each of the three structures 15. Fig. 38 is a partial top view showing the arrangement of the three structures 15 in the modified example of the wavelength converter 13 corresponding to Fig. 37 .

[0093] 37 and 38 , the size Kd of the openings KK of the light-shielding layer SK in the wavelength conversion device 13 of the light-emitting device 11 is preferably equal to or smaller than the size Td of the top surfaces FT of the structures 15. Each of the multiple openings KK in the light-shielding layer SK has an opening area equal to or smaller than the area of ​​the bottom surfaces of the multiple structures 15. That is, each of the multiple openings KK in the light-shielding layer SK overlaps with or is formed inside the outer edges of the top surfaces FT of the multiple structures 15 in a top view. Note that FIGS. 37 and 38 show the case where the openings KK of the light-shielding layer SK of the light-emitting device 11 are formed near and inside the outer edges of the top surfaces FT of the structures 15 (Kd<Td).

[0094] Figure 39 shows the light distribution characteristics of radiated light emitted from the top surface FT of one structure 15 in the light-emitting device 11 shown in Figure 37 when the structure 15 is a truncated cone of structure sample IV in Table 1 above. Figure 39(A) shows the light distribution characteristics of radiated light when the opening KK is a circular opening KK with a radius of 0.1 μm (= Kd / 2) from the central axis of the truncated cone structure 15, and Figure 39(B) shows the light distribution characteristics of radiated light when the opening KK is a circular opening KK with a radius of 0.2 μm (= Kd / 2) from the central axis of the truncated cone structure 15. It can be seen that the light-emitting device 11 shown in Figure 39 has an even narrower light distribution characteristic of illumination light than the narrow-angle light distribution characteristic of the light-emitting device shown in Figure 36 (Figure 35).

[0095] Furthermore, it is clear that the present invention includes appropriate modifications and combinations of the components of any of the above-described embodiments, examples, and modifications. Note that the light-emitting device 11 of any of the embodiments, examples, and modifications includes a light source 12 and a wavelength conversion device 13 arranged on the optical axis of the light emitted from the light source 12, and can be used as a light source for, for example, a projector, a vehicle lamp, a general light-emitting device, etc.

[0096] (Vehicle Headlamp) Figure 40 is a schematic cross-sectional view showing the configuration of a lamp body LMP (LED headlamp) equipped with the light-emitting device of the above-described embodiments and examples as a light-emitting module 21. The lamp body LMP includes a power supply section 20 and a lamp unit 30. In this example, a case where the lamp body LMP is a vehicle headlamp will be described.

[0097] The lamp unit 30 houses the light-emitting module 21, the condenser mirror 32, the projection lens 33, and the shade SH. The light-emitting module 21, the condenser mirror 32, the projection lens 33, and the shade SH are supported within the lamp unit 30 by a support SU. The lamp unit 30 is housed in a lamp body housing HS. The lamp body housing HS is provided with an outer lens OL in the area from which projection light PL is emitted from the projection lens 33 via an extension 31 around the projection lens 33. The projection light PL is extracted to the outside via the outer lens OL. The lamp unit 30 also has a bracket optical axis adjustment portion AJ for adjusting the optical axis of the lamp unit 30 relative to the lamp body housing HS.

[0098] The light-emitting module 21 is connected to the power supply unit 20 via a power supply line 22, and the light-emitting module 21 is provided with a heat dissipation unit SUH that dissipates heat generated from the light-emitting module 21. The power supply unit 20 is also provided with a power signal line CB that is connected to a battery (not shown), a control unit (not shown), and the like.

[0099] The collecting mirror 32 has, for example, an elliptical reflecting surface, and collects the diffused light DL from the light-emitting module 21 arranged at the first focal point to generate collected light FL that is collected at the second focal point F2. The projection lens 33 projects the collected light FL from the collecting mirror 32 to generate projection light PL.

[0100] The condenser mirror 32 can be formed by depositing a highly light-reflective film made of aluminum, silver, or the like on the surface of a molded body made of, for example, resin. The condenser mirror 32 may also be covered with a protective film. The projection lens 33 is made of a material that is translucent to the diffused light DL, such as glass, polycarbonate, or acrylic.

[0101] 40 , the diffused light DL from the light source travels radially from the first focal point (the light-emitting module 21) and is incident on the collecting mirror 32. The diffused light DL is collected at another focal point (a second focal point) F2 by the collecting mirror 32. The second focal point F2 also functions as the focal point of the projection lens 33.

[0102] The lamp unit 30 includes a shade SH for forming a low beam (a type of light distribution for passing vehicles) in an automotive headlamp. Specifically, the shade SH is configured to partially reflect the condensed light FL toward the projection lens 33. The shade SH is disposed within the lamp unit 30 so that a second focal point F2 is located at its end. The shade SH has a structure in which a highly reflective metal (e.g., aluminum or silver) is coated on a heat-resistant body. The shade SH is shaped to form a light-dark boundary line of the low beam cutoff line. The condensed light FL is partially reflected by the shade SH, so that the condensed light FL is shaped into a low beam as a whole and enters the projection lens 33. The shade SH may be movable. The shade SH is configured to be movable, for example, between a position within the optical path of the condensed light FL indicated by a solid line and a position outside the optical path of the condensed light FL indicated by a dashed line. Therefore, by moving the shade SH out of the optical path of the condensed light FL, the lamp unit 30 can form not only a low beam but also a driving beam distribution of the headlight (so-called high beam).

[0103] Figure 41 shows a low beam light distribution pattern and a high beam light distribution pattern to be formed on a virtual vertical screen placed, for example, 25 meters ahead of the vehicle, by light irradiated forward from the left and right lamp bodies LMP of the vehicle headlamp device of this embodiment.

[0104] The low-beam light distribution pattern PL in Figure 41 is formed by the shade SH of the lamp LMP. The low-beam light distribution pattern PL is a low-beam light distribution pattern for left-hand traffic in areas where traffic drives on the left, and has light-dark boundary lines (first cutoff lines CL1, second cutoff lines CL2, and third cutoff lines CL3) at its upper edge. The first cutoff lines CL1 and second cutoff lines CL2 extend horizontally at different levels on the left and right sides of a vertical line V-V (V axis) set in front of the lamp. The second cutoff line CL2 extends horizontally to the right of the vertical line V-V and below a horizontal line H-H (V axis) set in front of the lamp. For this reason, the second cutoff line CL2 is used as a cutoff line for oncoming traffic lanes.

[0105] The third cutoff line CL3 extends obliquely from the left end of the second cutoff line CL2 toward the upper left at an inclination angle of, for example, 45°. The first cutoff line CL1 extends on the horizontal line H-H to the left of the intersection of the third cutoff line CL3 and the horizontal line H-H. For this reason, the first cutoff line CL1 is used as a cutoff line for the vehicle's own lane. In the low beam light distribution pattern PL, elbow point E, which is the intersection of the second cutoff line CL2 and the vertical line V-V, is located approximately 0.5 to 0.6° below intersection point H-V, and a hot zone HZ, which should be a high-intensity area, is included surrounding this elbow point E slightly to the left.

[0106] The high-beam light distribution pattern HL in Fig. 42 is formed by opening the shade SH of the lamp LMP, thereby opening the upper portion of the light-dark boundary line (low-beam light distribution pattern PL), and expanding the hot zone HZ. In both light distribution patterns HL and PL, a medium-intensity region and a wide low-intensity region are sequentially illuminated around the high-intensity hot zone HZ.

[0107] In the headlamp described above, the light-emitting module 21 is required to have high brightness and uniform brightness distribution. Furthermore, since the light-emitting module 21 has a narrow-angle light distribution characteristic, the collector mirror 32 can be made smaller, and the lamp body LMP can be made more compact. For this reason, the light-emitting device to which the present invention is applied can be used more preferably.

[0108] 11 Light-emitting device 12 Light source 13 Wavelength converter 14 Wavelength converter 14C Transparent material part 15 Structure 15B Transparent support layer 16 Transparent body S1 Light-receiving surface S2 Light-emitting surface L1a Polariton component light L2 Dipole component light SK Light-shielding layer KK Opening

Claims

1. A light emitting device comprising: a light source; a thin-film wavelength converter arranged facing the light source; and a light-transmitting body arranged facing the wavelength converter, wherein the wavelength converter has a light-receiving surface facing the light source that receives primary light from the light source, a dielectric material that generates polariton component light from the primary light and a fluorescent material that generates dipole component light from the primary light, and a light-emitting surface opposite to the light source that emits the polariton component light and the dipole component light, wherein the light-transmitting body has a plurality of structures that protrude in a direction away from the light-emitting surface and are arranged along the light-emitting surface, and each of the structures has a columnar or upwardly tapered frustum-shaped side surface and a top surface intersecting with the side surfaces, wherein each of the plurality of structures receives the polariton component light and the dipole component light from the light-emitting surface, and the polariton component light and the dipole component light are totally reflected at the side surfaces to generate evanescent light, which is combined at the top surface of each of the plurality of structures and emitted.

2. The light emitting device of claim 1, wherein the side surfaces of each of the plurality of structures are inclined at an angle of 40 to 90 degrees relative to the light emitting surface of the wavelength converter, the side surfaces intersect with the top surface at an obtuse angle, and the height from the light emitting surface of the wavelength converter to the top surface is 250 to 2000 nm.

3. The light emitting device according to claim 2, characterized in that the width of the top surface of each of the plurality of structures parallel to the light emitting surface of the wavelength converter is 300 to 2000 nm.

4. The light emitting device according to claim 1, wherein the plurality of structures are periodically arranged on the light emitting surface of the wavelength converter.

5. The light emitting device according to claim 1, characterized in that the light transmissive body has a light transmissive support layer sandwiched between the plurality of structures and the wavelength conversion body and having a thickness of 300 nm or less.

6. The light emitting device according to claim 1, characterized in that the refractive index of the light transmissive material forming said light transmissive body is within the range of 1.30 to 2.50 for light with a wavelength of 550 nm.

7. The light emitting device according to claim 1, wherein the material forming the light transmitting body is an organic compound resin.

8. The light emitting device according to claim 1, wherein the material forming the light transmitting body is an inorganic transparent dielectric material or a ceramic.

9. The light emitting device according to claim 8, wherein said inorganic transparent dielectric material is glass or sapphire.

10. The light emitting device according to claim 1, wherein the wavelength conversion body has a thickness of 500 nm to 50 μm.

11. The light emitting device according to claim 1, wherein the wavelength conversion body has a light-transmitting material section that supports the light receiving surface in contact therewith.

12. The light emitting device according to claim 1, wherein the light source is a semiconductor light emitting element that generates light having a peak wavelength in the range of 380 nm to 490 nm.

13. The light emitting device according to claim 12, wherein said light source comprises an array of a plurality of light emitting elements, each of which emits said incident light toward each or each group of said plurality of structures.

14. The light emitting device according to claim 13, wherein each of the light emitting elements has a surface emitting portion.

15. The light emitting device according to claim 13, wherein each of said light emitting elements is a light emitting diode or a semiconductor laser that generates laser light.

16. The light emitting device according to claim 12, wherein the light source has an emission spectrum with a peak wavelength at 380 to 490 nm, and the intensity ratio of the polariton component light and the dipole component light is 1:1 to 1:

3.

17. The light emitting device according to claim 16, wherein the polariton component light and the dipole component light collectively have an emission spectrum having two or more peak wavelengths within the range of 380 to 780 nm.

18. The light emitting device according to claim 16, wherein the polariton component light has an emission spectrum with a peak wavelength λ1 within a range of 380 to 490 nm, and the dipole component light has an emission spectrum with a peak wavelength λ2 within a range of 490 to 780 nm.

19. The light emitting device according to claim 16, characterized in that the peak wavelength λ1 and the peak wavelength λ2 are apart by 50 nm or more.

20. The light emitting device according to claim 16, wherein said dielectric material is aluminum oxide, and said fluorescent material is an oxide containing cerium, yttrium and aluminum and having a garnet crystal structure.

21. The light-emitting device according to claim 1, characterized in that a light-shielding layer having a plurality of openings arranged so as to overlap each of the top surfaces of the plurality of structures in a top view is disposed between the wavelength conversion body and the light-transmitting body.

22. The light emitting device according to claim 21, wherein the light blocking layer is made of a metal mirror or a dielectric multilayer mirror.

23. The light emitting device according to claim 21, wherein the light shielding layer has a thickness of 5 nm to 5 μm.

24. The light-emitting device according to claim 21, characterized in that each of the multiple openings in the light-shielding layer overlaps with or is formed further inward than the outer edge of the bottom surfaces of the multiple structures when viewed from above.

25. The light-emitting device according to claim 24, characterized in that each of the multiple openings in the light-shielding layer overlaps with or is formed inside the outer edge of the top surfaces of the multiple structures when viewed from above.

26. The light emitting device according to claim 21, wherein the wavelength conversion body is disposed only within each of the plurality of openings of the light blocking layer.

27. The light-emitting device described in claim 5, characterized in that the translucent support layer has a large number of microcavities or air layers, or low refractive index material layers or high refractive index material layers arranged periodically or randomly therein, thereby suppressing multiple reflections within the wavelength conversion body.

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