Wavelength conversion member and lighting device using the same

Abstract

To provide a wavelength conversion member having narrow-angle light distribution, high output, and color unevenness, and a lighting device using the same.SOLUTION: The light emitting device includes a plate-shaped phosphor member including a phosphor that is excited by excitation light to emit fluorescence, a reflective member provided on a side surface of the phosphor member and configured to reflect the excitation light and the fluorescence, and a plurality of nano-antennas 37A, 37B, and 37C provided on one principal surface of the phosphor member and made of a metallic material or a dielectric material, wherein the plurality of nano-antennas include a first nano-antenna group arranged in a lattice pattern at a first arrangement period and a second nano-antenna group arranged in a lattice pattern at a second arrangement period. The first array period is a period corresponding to a first wavelength included in the wavelength range of the excitation light and the fluorescence, and the second array period is a period corresponding to a second wavelength included in the wavelength range of the excitation light and the fluorescence.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a wavelength conversion member and an illumination device using the same. [Background technology]

[0002] A device has been proposed that performs wavelength conversion on light emitted from a light source to mix light of different colors, and uses a nano-sized antenna (hereinafter referred to as a nanoantenna) to distribute the light emitted from the light source at a narrow angle.

[0003] For example, Patent Document 1 discloses a wavelength conversion device having a configuration including a light source that emits blue light, a phosphor plate that is excited by the light emitted from the light source and emits fluorescence, an antenna array in which multiple nanoantennas are arranged at a predetermined interval on the light-emitting surface of the phosphor plate, and a light-reflecting film on the side of the phosphor plate. Examples of the light-reflecting film disclosed include a white paint film, an optical multilayer reflective film, and a metal reflective film. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2018-13688 Summary of the Invention [Problem to be solved by the invention]

[0005] Consider a lighting device in which the wavelength conversion device described above is installed on the light-emitting surface of an LED. In this wavelength conversion device, providing a specularly reflective optical multilayer reflective film or a metal reflective film on the side of the phosphor plate as a light-reflecting film improves the narrow angle and light extraction efficiency compared to providing a diffusely reflective white paint film, but there is a problem in that color unevenness may occur.

[0006] The present invention has been made in consideration of the above-mentioned points, and aims to provide a wavelength conversion member that can be used to configure an illumination device with a narrow light angle, high output, and little color unevenness, and an illumination device using the same. [Means for solving the problem]

[0007] A wavelength conversion member according to the present invention includes a flat phosphor member containing a phosphor that is excited by excitation light to emit fluorescence, a reflecting member provided on a side surface of the phosphor member and reflecting the excitation light and the fluorescence, and a plurality of nanoantennas made of a metal material or a dielectric material provided on one main surface of the phosphor member, wherein the plurality of nanoantennas include a first group of nanoantennas arranged in a lattice pattern with a first arrangement period and a second group of nanoantennas arranged in a lattice pattern with a second arrangement period, and the first arrangement period is a period corresponding to a first wavelength included in the wavelength range of the excitation light and the fluorescence. the second arrangement period is a period corresponding to a second wavelength included in the wavelength range of the excitation light and the fluorescence, and the intensity ratio of light emitted from a first region in which the first nanoantenna group is formed in the phosphor material within a predetermined angle range centered on a direction perpendicular to the main surface is such that the light of the first wavelength is greater than the light of the second wavelength, and the intensity ratio of light emitted from a second region in which the second nanoantenna group is formed in the phosphor material within a predetermined angle range centered on a direction perpendicular to the main surface is such that the light of the second wavelength is greater than the light of the first wavelength. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a top view showing the configuration of an illumination device according to a first embodiment. [Figure 2] 1 is a cross-sectional view showing the configuration of an illumination device according to a first embodiment. [Figure 3A] FIG. 10 is a diagram showing the results of a simulation in which the proportion of light intensity within ±30° for an illumination device according to a comparative example of Example 1 is calculated for each nanoantenna pitch when the side surfaces are made of a diffuse reflection film. [Figure 3B]FIG. 10 is a diagram showing the results of a simulation in which the proportion of light intensity within ±30° for an illumination device according to a comparative example of Example 1 is calculated for each nanoantenna pitch when the side surfaces are made of a specular reflection film. [Figure 4A] FIG. 10 is a diagram showing the results of a simulation in which the proportion of light intensity within ±30° for an illumination device according to a comparative example of Example 1 is calculated for each nanoantenna pitch when the side surfaces are made of a diffuse reflection film. [Figure 4B] FIG. 10 is a diagram showing the results of a simulation in which the proportion of light intensity within ±30° for an illumination device according to a comparative example of Example 1 is calculated for each nanoantenna pitch when the side surfaces are made of a specular reflection film. [Figure 5A] FIG. 10 is a diagram showing a simulation result of a light distribution pattern of an illumination device according to a comparative example of Example 1. [Figure 5B] FIG. 4 is a diagram showing a simulation result of a light distribution pattern of the lighting device according to Example 1. [Figure 6A] FIG. 10 is a diagram showing a simulation result of a light distribution pattern of an illumination device according to a comparative example of Example 1. [Figure 6B] FIG. 4 is a diagram showing a simulation result of a light distribution pattern of the lighting device according to Example 1. [Figure 7] 10 is a diagram showing the relationship between the regular reflectance at the side surface of the phosphor member of the lighting device according to the comparative example of Example 1 and the light extraction efficiency of the lighting device. FIG. [Figure 8] FIG. 10 is a top view showing the configuration of an illumination device according to a second embodiment. [Figure 9] FIG. 10 is a top view showing the configuration of an illumination device according to a first modified example of the second embodiment. [Figure 10] FIG. 10 is a top view showing the configuration of an illumination device according to a second modification of the second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] In the following, preferred embodiments of the present invention will be described, but these may be modified and combined as appropriate. In the following description and accompanying drawings, substantially the same or equivalent parts are designated by the same reference numerals. [Example]

[0010] The configuration of an illumination device 100 according to a first embodiment of the present invention will be described with reference to Fig. 1 and Fig. 2. Fig. 1 is a top view showing the configuration of the illumination device 100 according to the first embodiment. Fig. 2 is a cross-sectional view of the illumination device 100 taken along line 2-2 in Fig. 1.

[0011] The lighting device 100 includes a mounting substrate 11, a light-emitting element 13 flip-chip mounted on the mounting substrate 11, and a wavelength conversion member 15 provided on the light-emitting element 13. The wavelength conversion member 15 is a member including a phosphor member 35 that is excited by light emitted from the light-emitting element 13 and emits fluorescence.

[0012] As shown in FIG. 1, the mounting substrate 11 is a flat substrate with a rectangular top surface. The mounting substrate 11 is made of an insulating material. Preferably, the mounting substrate 11 has high heat dissipation properties. In this embodiment, the mounting substrate 11 is made of aluminum nitride (AlN) ceramic, which is insulating and has high heat dissipation properties. However, the mounting substrate 11 may also be made of other insulating materials, such as alumina.

[0013] 2, a p-type wiring electrode 11A and an n-type wiring electrode 11B, which are metal electrodes spaced apart from each other, are formed on the upper surface of the mounting substrate 11. The p-type wiring electrode 11A and the n-type wiring electrode 11B are electrically connected to an external power supply (not shown).

[0014] The light-emitting element 13 is an LED element comprising a substrate 17, a semiconductor stack 25 consisting of multiple nitride-based semiconductor layers including an active layer formed on the underside of the substrate 17, a p-electrode 27, and an n-electrode 31.

[0015] Substrate 17 is a flat sapphire substrate having a rectangular upper surface. Substrate 17 is a growth substrate for the semiconductor layers that constitute light-emitting element 13. As shown in FIG. 2, the lower surface of substrate 17 is the growth surface for the semiconductor layers. In addition, wavelength conversion member 15 is provided on the upper surface of substrate 17. The upper and lower surfaces of substrate 17 are flat surfaces that do not have an intentionally formed uneven structure, for example. In addition, substrate 17 is translucent to light emitted from the active layer, and the light from the active layer passes through substrate 17 and enters wavelength conversion member 15.

[0016] The semiconductor stack 25 is a stacked structure including multiple semiconductor layers formed to cover the lower surface of the substrate 17. The semiconductor stack 25 includes an n-type semiconductor layer 19, an active layer 21, and a p-type semiconductor layer 23, which are epitaxially grown in this order on the substrate 17 by MOCVD.

[0017] N-type semiconductor layer 19 as a first semiconductor layer is formed so as to cover the lower surface of substrate 17, and is an n-type GaN layer doped with n-type impurities as a first conductivity type. N-type semiconductor layer 19 is doped with, for example, Si as the n-type impurity.

[0018] The n-type semiconductor layer 19 has a mesa shape. Specifically, the n-type semiconductor layer 19 has a recessed region 1 (the right side in FIG. 2 ), which is a region along the outer edge of the lower surface to which the n-electrode 31 is connected, and the other regions other than the region 1 form a plateau. The region 1 has a surface 19E that is recessed further than the surfaces of the plateau portions of the other regions.

[0019] The active layer 21 is formed on a mesa-shaped plateau portion on the lower surface of the n-type semiconductor layer 19. The wavelength of light emitted from the active layer depends on the material and composition of the semiconductor laminate 25. In this embodiment, the active layer 21 is a semiconductor layer having a multi-quantum well (MQW) structure made up of InGaN well layers and GaN barrier layers. In this embodiment, the emission peak wavelength of the active layer 21 is within the range of 450±20 nm.

[0020] The p-type semiconductor layer 23 as the second semiconductor layer is formed across the lower surface of the active layer 21, and is a layer made up of a plurality of semiconductor layers including a p-type GaN layer doped with p-type impurities as a second conductivity type. The p-type GaN layer of the p-type semiconductor layer 23 is doped with, for example, Mg as the p-type impurity.

[0021] The p-type semiconductor layer 23 is configured by stacking, on the lower surface of the active layer 21, for example, an electron blocking layer made of an AlGaN layer, a p-type cladding layer made of a p-type GaN layer, and a contact layer made of a p-type GaN layer doped with Mg at a higher concentration than the p-type cladding layer, in this order.

[0022] The p-electrode 27 is a metal electrode formed across the lower surface of the p-type semiconductor layer 23. The p-electrode 27 is electrically connected to the p-type semiconductor layer 23. The p-electrode 27 is electrically connected to the p-wiring electrode 11A on the mounting substrate 11 by AnSu eutectic via a conductive p-type electrode pad 29.

[0023] Furthermore, p-electrode 27 preferably has the property of reflecting light emitted from active layer 21. P-electrode 27 is preferably made of a metal with high reflectivity, such as aluminum (Al) or silver (Ag), or an alloy thereof. P-type electrode pad 29 is made of a metal film in which Ti, Pt, and Au are laminated in this order on p-electrode 27, for example.

[0024] The n-electrode 31 is a metal electrode provided on the exposed surface 19E of the n-type semiconductor layer 19. The n-electrode 31 is electrically connected to the n-type semiconductor layer 19. The n-electrode 31 is also electrically connected to the n-wiring electrode 11B on the mounting substrate 11 by AnSu eutectic via a conductive n-type electrode pad 33. The n-type electrode pad 33 is made of a metal film in which, for example, Ti, Pt, and Au are laminated in this order on the n-electrode 31.

[0025] As described above, light emitting element 13 is flip-chip mounted on mounting substrate 11, and the upper surface of substrate 17 serves as a light emitting surface of light emitting element 13. Although the light emitting element 13 has been described as having a mesa shape, the present invention is not limited to this, and n-type semiconductor layer 19 and n-wiring electrode 11B may be electrically connected via a through hole that is provided in semiconductor laminate 25 and extends from p-type semiconductor layer 23 to n-type semiconductor layer 19.

[0026] The wavelength conversion member 15 includes a phosphor member 35, a plurality of nanoantennas 37A to 37C provided on an upper surface 35S of the phosphor member 35, and a reflecting member 39 provided on a side surface of the phosphor member 35.

[0027] The phosphor member 35 is a flat plate-shaped member having a rectangular upper surface. The phosphor member 35 contains a phosphor that emits fluorescence when excited by light emitted from the active layer 21. In this embodiment, the phosphor member 35 is a ceramic phosphor plate made of a single layer of yttrium aluminum garnet (YAG:Ce) with cerium as the luminescence center. The phosphor member 35 is bonded to the substrate 17 of the light-emitting element 13. The surface of the phosphor member 35 that is bonded to the light-emitting element 13, i.e., the lower surface of the phosphor member 35 in FIG. 2, is a flat surface.

[0028] The phosphor member 35 may be, for example, a plate having a thin film containing a phosphor formed on the surface of a transparent support, or may be a resin or glass layer containing phosphor particles such as YAG:Ce phosphor.

[0029] The phosphor described above is excited by blue light with a wavelength of approximately 450 nm and emits yellow fluorescence with a wavelength of approximately 480 to 750 nm. Therefore, in this embodiment, when blue light with a peak wavelength of 450±20 nm emitted from the active layer 21 is introduced into the phosphor member 35, a portion of the blue light is wavelength-converted to yellow fluorescence. The remaining blue light passes through the phosphor member 35 without being wavelength-converted. Therefore, the blue light that has passed through the phosphor member 35 and the yellow fluorescence from the phosphor contained in the phosphor member 35 are emitted from the upper surface 35S of the phosphor member 35.

[0030] White light is extracted from the lighting device 100 by mixing the blue light and yellow fluorescence emitted from the upper surface 33S of the phosphor member 35. In order to achieve stable white light, the phosphor member 35 preferably has a thickness within a range of 40 to 200 μm. In this embodiment, the thickness of the phosphor member 35 is 100 μm.

[0031] [Nano Antenna] Nanoantenna 37A, nanoantenna 37B, and nanoantenna 37C (hereinafter collectively referred to as nanoantennas 37A to 37C) are cylindrical structures made of TiO 2 arranged on the upper surface of phosphor member 35.

[0032] 1, in a top view, that is, in a plan view seen from a direction perpendicular to the top surface 35S of the phosphor member 35, the phosphor member 35 has, on the top surface 35S, strip-shaped regions AR1 to AR3 along one side of the phosphor member 35. Region AR1 is a region where a plurality of nanoantennas 37A are arranged, region AR2 is a region where a plurality of nanoantennas 37B are arranged, and region AR3 is a region where a plurality of nanoantennas 37C are arranged.

[0033] The arrangement period of the nanoantennas 37A in region AR1, the arrangement period of the nanoantennas 37B in region AR2, and the arrangement period of the nanoantennas 37C in region AR3 are all different. The multiple nanoantennas 37A to 37C are arranged in a lattice-like arrangement pattern at regular intervals in each of regions AR1 to AR3 on the upper surface 35S of the phosphor member 35. In other words, the multiple nanoantennas 37A to 37C are arranged in a regular arrangement pattern at regular intervals in each of regions AR1 to AR3 in a top view to form an antenna array. In this embodiment, the multiple nanoantennas 37A to 37C are arranged to form a triangular lattice.

[0034] Specifically, the region AR1 as the first region is a region where a plurality of nanoantennas 37A are arranged with an array period L1. The region AR2 as the second region is a region where a plurality of nanoantennas 37B are arranged with an array period L2 that is larger than the array period L1. The region AR3 as the third region is a region where a plurality of nanoantennas 37C are arranged with an array period L3 that is larger than the array period L2. That is, the array periods L1 to L3 are different from each other, with the array period L1 being the smallest and the array period L3 being the largest (L1 < L2 < L3). In this embodiment, the array period L1 is 360 nm, the array period L2 is 440 nm, and the array period L3 is 500 nm.

[0035] In other words, in the first region, a first nanoantenna group is formed in which a plurality of nanoantennas 37A are arranged in a lattice pattern with an array period L1 as the first array period. In the second region, a second nanoantenna group is formed in which a plurality of nanoantennas 37B are arranged in a lattice pattern with an array period L2 as the second array period. In the region AR3, a third nanoantenna group is formed in which a plurality of nanoantennas 37C are arranged in a lattice pattern with an array period L3 as the third array period.

[0036] In this embodiment, the diameter of each of the plurality of cylindrical nanoantennas 37A to 37C in a top view is 80% of the array period. That is, the diameter of the nanoantenna 37A is 288 nm, the diameter of the nanoantenna 37B is 352 nm, and the diameter of the nanoantenna 37C is 400 nm.

[0037] Also, as shown in FIG. 2, the height H of each of the plurality of nanoantennas 37A to 37C is common among the nanoantennas 37A to 37C and is, for example, 100 nm to 400 nm. If the height is too low, the scattering by the nanoantenna becomes small and the intensity of the emitted light taken out becomes low. Also, if the aspect ratio (height / diameter) is too large compared to 1, manufacturing becomes difficult. In this embodiment, the height H is set to 300 nm and 350 nm. This dimension is set to be an aspect ratio considering ease of manufacturing and durability during practical use.

[0038] The nanoantennas 37A to 37C may be shaped like a column or a pyramid, and may be shaped like a square column, a cone, a pyramid, or any other shape besides a cylindrical column. In this case, it is preferable that the maximum width of the nanoantennas 37A to 37C in a top view is 75% to 85% of the arrangement period, from the viewpoints of narrowing the angle and increasing the intensity of the emitted light. The nanoantennas 37A to 37C may be formed from a dielectric material such as TiO, AlO, NbO, HfO, ZrO, TaO, CeO, LaO, AlN, GaN, SiN, SiC, or other metal oxides, nitrides, or carbides, or from a metal material such as Al, Au, Ag, or Ni.

[0039] [Reflective material] As shown in FIG. 2, the reflective member 39 is provided on the side surface 35E of the phosphor member 35. The reflective member 39 is composed of a dielectric multilayer film 41 formed on the side surface of the phosphor member 35 and a metal film 43 formed on the dielectric multilayer film 41. The reflective member 39 has the function of reflecting light that reaches the side surface of the phosphor member 35. It is preferable that the reflective member 39 increases the specular reflectance of the reflected light that reaches the side surface of the phosphor member 35, and the specular reflectance of the reflected light is preferably 80% or more. It is preferable that the side surface 35E of the phosphor member 35 is smoothed to increase the specular reflectance of the reflective member 39. In this embodiment, the reflective member 39 is also provided on the side surface of the light-emitting element 13 and covers the side surface of the light-emitting element 13.

[0040] The dielectric multilayer film 41 is a dielectric multilayer film reflector formed by stacking multiple dielectric films with different refractive indices, and is configured to reflect light within a predetermined wavelength range that is incident at a predetermined angle range.

[0041] Examples of low refractive index dielectric materials include silicon oxide (SiO2) and alumina (Al2O3).High refractive index dielectric materials are preferably titanium oxide (TiO2), zirconia (ZrO2), niobium pentoxide (Nb2O5), lanthanum oxide (La2O3), tantalum oxide (Ta2O5), and hafnium oxide (HfO2), which have low light absorption.In this embodiment, the dielectric multilayer film 41 is formed by alternately stacking 39 layers of silicon oxide (SiO2) and niobium pentoxide (Nb2O5).

[0042] In this embodiment, the reflection of light by the dielectric multilayer film 41 is a reflection at the interface between the low refractive index material and the high refractive index material, and is a regular reflection in which the angle of incidence and the angle of reflection are equal.

[0043] The metal film 43 is a metal film formed on the surface of the dielectric multilayer film 41. The metal film 43 is made of a metal with high reflectivity, such as aluminum (Al) or silver (Ag). The metal film 43 reflects light that is outside a predetermined angle range or a predetermined wavelength range and has passed through the dielectric multilayer film 41 to reach the metal film 43. The reflection by the metal film 43 is a reflection on the metal surface, and is a specular reflection.

[0044] In this embodiment, by providing a reflecting member 39 that causes specular reflection on the side surface of the phosphor member 35, more light reaches the upper surface of the phosphor member 35 at an angle at which diffraction by the nanoantennas is likely to occur, i.e., more light is incident on the upper surface of the phosphor member 35 at an angle at which diffraction is likely to occur, compared to the case where a reflecting member that causes diffuse reflection is provided. The details of how providing a reflecting member 39 made of a specular reflection material increases the amount of light that is incident on the upper surface of the phosphor member 35 at an angle at which diffraction is likely to occur, i.e., at or above the critical angle, will be described later.

[0045] [Nanoantenna arrangement period and function] The arrangement period and light diffraction function of the nanoantennas 37A to 37C will be described below. As described above, the lighting device 100 is a device that provides white light by mixing blue light and yellow fluorescent light emitted from the upper surface 33S of the phosphor member 35.

[0046] If the nanoantennas 37A to 37C are not provided on the phosphor member 35, the white light is more likely to have color unevenness due to the difference in light distribution characteristics between the blue light passing through the phosphor member 35 and the yellow light emitted by the phosphor contained in the phosphor member 35. Specifically, the blue light passing through the phosphor member 35 and emitted from the upper surface 35S tends to have a narrower light distribution angle than the yellow light. On the other hand, because the fluorescence from the phosphor is emitted isotropically, the yellow fluorescence tends to have a Lambertian light distribution. Therefore, the white light emitted from the lighting device tends to be more bluish in the direction perpendicular to the upper surface than in other directions.

[0047] To address color unevenness caused by the difference in light distribution between the blue light and the yellow fluorescence, a nanoantenna with a light diffraction function is provided on the upper surface 35S of the phosphor member 35. In the lighting device 100, by diffracting the fluorescence emitted from the upper surface 35S, the light distribution of the fluorescence is narrowed in angle, bringing it closer to the light distribution of the blue light, thereby eliminating color unevenness.

[0048] Here, we will explain the angle-narrowing effect of the nanoantenna. When light reaches the top surface 35S of the phosphor member 35 at an angle equal to or greater than the critical angle, the light is totally reflected by the top surface 35S of the phosphor member 35. When total reflection occurs, an evanescent wave is generated that seeps from the top surface 35S of the phosphor member 35 toward the low-refractive-index medium. This evanescent wave propagates along the top surface 35S, in other words, along the interface between the phosphor member 35 and air.

[0049] The evanescent waves propagating along the upper surface of the phosphor member 35 are scattered when they reach the nanoantennas and are emitted as visible light with the same wavelength as the fluorescence in a direction that conforms to the diffraction conditions determined by the arrangement period of the nanoantennas. This phenomenon causes the light to be emitted in a light distribution angle range (emission angle range) that conforms to the diffraction conditions, thereby promoting a narrowing of the angle of light emitted from the upper surface of the phosphor member 35. Narrowing the angle of fluorescence by the nanoantennas means, for example, that the action of the nanoantennas increases the amount of fluorescence emitted at a light distribution angle within ±30°.

[0050] Note that light incident on the upper surface 35S of the phosphor member 35 at an angle less than the critical angle is less likely to be diffracted and is transmitted, so that it is less likely to have a narrow-angle light distribution. In other words, light incident on the upper surface 35S at an angle equal to or greater than the critical angle is more likely to be diffracted, and the greater the proportion of light that reaches the upper surface 35S at an angle equal to or greater than the critical angle, the more diffracted light there is.

[0051] The inventors of the present application have discovered that when the period of a nanoantenna having the above-described diffraction function is a single period, the light distribution, for example, the proportion of light intensity within 30 degrees, varies depending on the wavelength, but that this tendency becomes more pronounced when a reflective member 39 that specularly reflects light from within the phosphor member 35 is provided, as in this embodiment.

[0052] Therefore, in this embodiment, nanoantennas 37A to 37C are provided in regions AR1 to AR3, respectively, and are arranged at arrangement periods L1 to L3. The arrangement periods L1 to L3 of nanoantennas 37A to 37C correspond to the wavelengths included in the wavelength ranges of blue light and yellow fluorescence, respectively. Specifically, each of the arrangement periods L1 to L3 is an arrangement period that makes it easier for light of any wavelength included in the wavelength ranges of blue light and yellow fluorescence to be diffracted by the nanoantenna and narrowed in angle.

[0053] The inventors discovered that by setting the arrangement period of the nanoantennas in this way, deviations in the light distribution of light with different colors can be reduced, resulting in uniform white light with little color unevenness.

[0054] [Reflective element enhances diffraction] The increase in light diffracted by the nanoantennas by the reflecting member 39 can be explained as follows: Of the light that propagates through the phosphor member 35 and reaches the top surface 35S, the ratio of light that is extracted by transmission or diffraction by the nanoantennas to light that is reflected by the top surface 35S is about 1:5, meaning that most of the light is reflected by the top surface 35S and returns into the phosphor member 35.

[0055] The light reflected by the upper surface 35S includes light that is totally reflected at the interface between the phosphor member 35 and air at the upper surface 35S and light that is reflected by the lower surface of the nanoantenna. The light reflected by the upper surface 35S is reflected by, for example, the side surface of the phosphor member 35, the rear surface of the phosphor member 35, the p-electrode 27 of the light-emitting element 13, etc., and then enters the upper surface 35S again.

[0056] As described above, when light is incident on the upper surface 35S at an angle equal to or greater than the critical angle and is totally reflected, diffraction by the nanoantennas is likely to occur. Therefore, if the incident angle when the light is reflected on the side surface of the phosphor member 35 and then incident on the upper surface 35S again is equal to or greater than the critical angle, diffraction is likely to occur.

[0057] For example, consider a case where a light-scattering resin member is provided on the side surface of the phosphor member 35 instead of the reflective member 39. The resin member is, for example, a so-called white resin, in which light-scattering particles (e.g., titanium oxide (TiO2) particles) are dispersed in a transparent resin. Because the refractive index of the resin member is greater than that of air, the critical angle at the interface between the phosphor member 35 and the resin member is greater than the critical angle at the interface between the phosphor member 35 and the air. In this case, when light reflected from the upper surface 35S reaches the side surface of the phosphor member 35, light below the critical angle is transmitted through the interface without being totally reflected and is diffusely reflected by the scattering particles contained in the resin member. For example, light that was above the critical angle when it first entered the upper surface 35S changes its incident angle to various angles when it re-enters the upper surface 35S after diffuse reflection, resulting in less light incident above the critical angle. This reduces the amount of light diffracted, lowering the proportion of light extracted at a narrow angle. Furthermore, light is absorbed by the reflecting surfaces such as the side and rear surfaces of the phosphor member 35, which reduces the light extraction efficiency.

[0058] In this embodiment, as described above, by using the reflecting member 39 to specularly reflect light at the side surface of the phosphor member 35, light that reaches a critical angle or greater when re-entering the nanoantenna can reach the top surface of the phosphor member 35 while maintaining that angle. Also, due to the nature of the dielectric multilayer film, there is almost no light absorption by the dielectric multilayer film 41. In this embodiment, since much light is diffracted and absorption is low, there is little loss due to diffuse reflection and absorption of light, and the efficiency of extracting narrow-angle light from the top surface 35S of the phosphor member 35 is higher than in a configuration in which the reflecting member 39 is not provided.

[0059] In this embodiment, the reflective member 39 is also provided on the side surface of the light-emitting element 13, but it is sufficient that the reflective member 39 is provided at least on the side surface of the phosphor member 35. In other words, to obtain the above effect, it is sufficient that the reflective member 39 is formed only on the side surface of the phosphor member 35. It is preferable that the reflective member 39 is also provided on the side surface of the light-emitting element 13, because this allows more light to be specularly reflected and more light to reach the upper surface of the phosphor member 35 at an angle at which it is easily diffracted.

[0060] In this embodiment, the regions where the multiple nanoantennas 37A to 37C are formed may be formed in any region of the upper surface 35S. For example, the regions AR1 to AR3 may be regions where the semiconductor laminate 25 of the light-emitting element 13 is formed in top view. In this embodiment, the regions AR1 to AR3 are formed over the entire upper surface of the phosphor member 35. In other words, the nanoantennas are formed over the entire upper surface 35S of the phosphor member 35.

[0061] In this embodiment, if the proportions of the area of ​​the regions AR1 to AR3 to the area of ​​the upper surface 35S of the phosphor member 35 are taken as area proportions S1 to S3, they are all the same proportion, that is, S1=S2=S3=1 / 3.

[0062] 1 and 2 are merely shown schematically to explain the nanoantennas 37A to 37C, and are not to the actual scale. The phosphor member 35 is, for example, 1 mm square, and in this case, more nanoantennas 37A to 37C are provided than those shown in FIGS.

[0063] [Nanoantenna arrangement period] The method for setting the arrangement periods L1 to L3 of the nanoantennas 37A to 37C will be described below. First, a wavelength (also referred to as a target wavelength) to be controlled by the nanoantenna for light distribution is selected. In this example, to obtain white light by mixing blue light and yellow fluorescent light, a target wavelength included in the wavelength range of the mixed light of the blue light and yellow fluorescent light is selected.

[0064] The peak wavelength of the emission spectrum of blue light emitted from a nitride-based blue light-emitting element used in the light-emitting element 13 is generally approximately 450 nm. However, taking into consideration that this may vary depending on the material and structure of the active layer, the wavelength range of the blue light was set to 430 nm to 470 nm (i.e., 450±20 nm) (first wavelength band). In this embodiment, the center wavelength of the first wavelength band, 450 nm, was set as the target wavelength (first wavelength) for which the nanoantenna controls the light distribution of blue light. That is, the period of the nanoantenna 37A was set based on the results of analytically determining the period at which 450 nm light is most effectively diffracted. Specifically, the period of the nanoantenna 37A can be determined based on the light intensity obtained by analyzing, for various periods, the intensity of 450 nm light emitted via the nanoantenna 37 within ±30° of the direction perpendicular to the upper surface 35S of the phosphor member 35 using RCWA (Rigorous Coupled Wave Analysis). As a result, light of 450 nm±20 nm is diffracted well, and the intensity of the light distributed in the direction perpendicular to the upper surface 35S of the phosphor member 35 at ±30 degrees is increased.

[0065] The emission spectrum of yellow fluorescence from a phosphor made of YAG:Ce generally exhibits a broad peak near approximately 550 nm. The peak wavelength of the yellow fluorescence is, for example, 520 nm or more and 570 nm or less. The wavelength with the highest luminosity is 555 nm (green to yellow). Taking into consideration the peak wavelength of the yellow fluorescence and the wavelength with high luminosity, the wavelength range of the yellow light was set to 530 nm or more and 570 nm or less (550±20 nm) (second wavelength band) so that the center wavelength was close to the wavelength with high luminosity. In this example, the center wavelength of 550 nm of the second wavelength band was set as the target wavelength (second wavelength) for light distribution control of the yellow light by the nanoantenna.

[0066] That is, the period of the nanoantenna 37B was set based on the results of an analysis that determined the period that best diffracts 550 nm light. Specifically, the period of the nanoantenna 37B can be determined by analyzing the intensity of 550 nm light emitted via the nanoantenna 37 within ±30° of the direction perpendicular to the top surface 35S of the phosphor member 35 using the RCWA method for various periods, and then selected based on the obtained light intensity. This results in excellent diffraction of 550 nm ±20 nm light, increasing the intensity of the light distributed within ±30° of the direction perpendicular to the top surface 35S of the phosphor member 35. Note that while the wavelength around 550 nm is the boundary between yellow and green light, for simplicity, 550 ±20 nm is treated as the wavelength range of yellow light.

[0067] The second wavelength band can be changed depending on the type of phosphor used in the phosphor member 35, i.e., the spectrum of the emission wavelength of the phosphor. Specifically, if the peak of the spectrum of the emission wavelength of the phosphor shifts, the second wavelength band can also shift accordingly. For example, if the wavelength of 555 nm, at which visibility is high, is significantly different from the peak wavelength of the fluorescence, it is preferable to change the second wavelength band accordingly depending on the peak wavelength.

[0068] Furthermore, when white light is obtained by mixing blue and yellow light, if the red component is insufficient, the white light may have a strong bluish green tint, and the appropriate chromaticity may not be obtained. In particular, the single-phase YAG:Ce used as the phosphor member 35 in this embodiment is prone to a lack of red. While it is conceivable to increase the reddish tint by increasing the Ce content or adding Gd (gadolinium), these methods are undesirable because they create voids within the phosphor member 35, causing internal scattering.

[0069] In this embodiment, the wavelength of red light is also set as a target wavelength for controlling the light distribution by the nanoantenna, and the light distribution of light with a wavelength corresponding to the reddish component is controlled to a narrow angle by the nanoantenna, concentrating the reddish component at the required light distribution angle, thereby producing the desired white light.

[0070] The emission spectrum of yellow fluorescence from a phosphor made of YAG:Ce generally exhibits a base where intensity gradually decreases from approximately 600 nm to approximately 700 nm, which is included in the wavelength range of red light. In this embodiment, the wavelength range of red light is set to 600 nm to 700 nm (third wavelength band), and its center wavelength of 650 nm is set as the target wavelength (third wavelength) for light distribution control by the nanoantenna. That is, the period of nanoantenna 37C is set based on the results of analytically determining the period at which 650 nm light is most effectively diffracted. Specifically, the period of nanoantenna 37C can be determined by analyzing the intensity of 650 nm light emitted via nanoantenna 37 within ±30° in the direction perpendicular to the top surface 35S of phosphor member 35 using the RCWA method for various periods, and then selected based on the obtained light intensity. This results in excellent diffraction of light from 600 to 700 nm, increasing the intensity of light distributed within ±30° in the direction perpendicular to the top surface 35S of phosphor member 35.

[0071] Next, the setting of the arrangement periods L1 to L3 will be explained using Fig. 3. Fig. 3 is a diagram showing the results of a simulation in which the proportion of light intensity within an emission angle of ±30° is calculated for each wavelength for a comparative example in which the nanoantenna arrangement period is a single period in the lighting device of this embodiment. Fig. 3 shows the proportion of light intensity within an emission angle of ±30° for the above-mentioned target wavelengths of 450 nm, 550 nm, and 650 nm, when the total light intensity in all directions (total luminous flux) is set to 100% when the nanoantenna arrangement period is changed.

[0072] FIG. 3A shows a comparative example (Comparative Example 1) in which a reflective member with different light scattering properties from the reflective member 39 of this embodiment is provided. The simulation results show that Lambertian scattering occurs on the side surfaces and rear surface (i.e., bottom surface) of the phosphor member 35. In this simulation, the ratio of light intensity within ±30° was calculated under the condition that 10% of the light is absorbed on the side surfaces and rear surface of the phosphor member 35, and the remainder is Lambertian scattered (the Lambertian scattering condition). In other words, the simulation results show that 10% of the light reaching the side surfaces and rear surface of the phosphor member 35 is absorbed, and 90% is Lambertian scattered and returns to the phosphor member 35. The reflective member of Comparative Example 1 is also referred to as a diffuse reflective film. In Comparative Example 1, it is assumed that the rear surface of the phosphor member 35 or the bonding surface of the sapphire substrate 17 with the phosphor member 35 is rough. In the following explanation of the simulation, a surface on which light reflection occurs under the above-mentioned Lambertian scattering conditions, that is, a surface on which 10% of the light that reaches it is absorbed and 90% is Lambertian scattered, is referred to as a Lambertian scattering surface.

[0073] FIG. 3B shows a comparative example (Comparative Example 2) in which a reflective member 39 similar to that of this embodiment is provided. The simulation results are based on the condition that specular reflection occurs but light is not absorbed (specular reflection conditions) on the side and back surfaces of the phosphor member 35. In other words, the simulation results are based on the case where 100% of the light reaching the side and back surfaces of the phosphor member 35 is specularly reflected and returns to the phosphor member 35. The reflective member of Comparative Example 2 is also referred to as a specular reflection film. In Comparative Example 2, it is assumed that the back surface of the phosphor member 35 or the bonding surface of the sapphire substrate 17 with the phosphor member 35 is smooth and does not scatter light from the light emitting element 13. In the following description of the simulation, a surface where light reflection occurs under the specular reflection conditions described above, i.e., where all light reaching the surface is specularly reflected, is referred to as an ideal specular reflection surface.

[0074] The simulation was performed using the RCWA (Rigorous Coupled-Wave Analysis) method and ray tracing. The simulation conditions were as follows: The phosphor member 35 was 1 mm square and 0.1 mm (i.e., 100 μm) thick. The nanoantenna material was TiO2 and had a cylindrical shape. The diameter of the nanoantenna was 80% of the period, and the height of the nanoantenna was constant at 300 nm. The nanoantennas were arranged in a triangular lattice pattern. The nanoantenna period was changed from 300 nm to 540 nm in 20 nm intervals for a wavelength of 450 nm, and from 360 nm to 540 nm in 20 nm intervals for wavelengths of 550 nm and 650 nm.

[0075] As shown in Figure 3A, in Comparative Example 1, the proportion of light intensity within ±30° was approximately 33% at most, whereas as shown in Figure 3B, in Comparative Example 2, the proportion of light intensity within ±30° exceeded 40% at each wavelength. Under the Lambertian scattering conditions of Comparative Example 1, the reflection angle changed relative to the incident angle each time light was reflected from the side or back surface of phosphor member 35, which is thought to have reduced the amount of light incident on top surface 35S at angles greater than the critical angle at which diffraction is likely to occur. In other words, the proportion of light that passes through phosphor member 35 without being diffracted and exits top surface 35S increased, resulting in a reduced narrow-angle characteristic.

[0076] In contrast, under the specular reflection conditions of Comparative Example 2, specular reflection occurs on the side and back surfaces of the phosphor member 35, so that the amount of light incident on the upper surface 35S at angles greater than the critical angle is not reduced, making it easier for diffraction by the nanoantennas to occur, resulting in a higher narrow angle.

[0077] Although not shown, the total luminous flux was also higher in Comparative Example 2 than in Comparative Example 1. This result indicates that Comparative Example 2 has high light extraction efficiency because there is no light absorption.

[0078] Thus, while the light intensity ratio within ±30° was high overall, there was a noticeable tendency for the period at which the light intensity ratio within ±30° was highest to differ depending on the wavelength in Comparative Example 2. For example, in the period of 420 to 440 nm at which the light intensity ratio within ±30° of the wavelength 550 nm, which has high luminosity, is highest, the light intensity ratio within ±30° of light with a wavelength of 650 nm (red light) is approximately 10% lower than the light intensity ratio within ±30° of light with a wavelength of 550 nm (green to yellow light).

[0079] Therefore, in Comparative Example 2, when the arrangement period of the nanoantennas is set to a single period of 420 to 440 nm, the light extracted at a narrow angle within ±30° becomes light that is less reddish and leans towards green.

[0080] Therefore, in this example, the nanoantenna arrangement periods L1 to L3 were selected to provide a high optical intensity ratio within ±30° for each of the wavelengths of 450 nm, 550 nm, and 650 nm. Specifically, the arrangement period L1 corresponding to the 450 nm wavelength was set to 360 nm, the arrangement period L2 corresponding to the 550 nm wavelength was set to 440 nm, and the arrangement period L3 corresponding to the 650 nm wavelength was set to 500 nm.

[0081] By selecting the array period as described above, the intensity ratio of light emitted from region AR1, where nanoantennas are formed with array period L1, within ±30° of the direction perpendicular to the top surface 35S (0°) is the center, is highest for light with a wavelength of 450 nm. Furthermore, the intensity ratio of light emitted from region AR2, where nanoantennas are formed with array period L2, within ±30° of the direction perpendicular to the top surface 35S (0°) is the center, is highest for light with a wavelength of 550 nm. Furthermore, the intensity ratio of light emitted from region AR3, where nanoantennas are formed with array period L3, within ±30° of the direction perpendicular to the top surface 35S (0°) is the center, is highest for light with a wavelength of 650 nm.

[0082] In other words, of the light of wavelengths of 450 nm, 550 nm, and 650 nm included in the wavelength ranges of excitation light and fluorescence, light of wavelength 450 nm is most likely to have a narrow-angle light distribution in area AR1, light of wavelength 550 nm is most likely to have a narrow-angle light distribution in area AR2, and light of wavelength 650 nm is most likely to have a narrow-angle light distribution in area AR3.

[0083] Regarding the wavelength of 450 nm, in Figure 3B, the light intensity ratio within ±30° is higher at 340 nm, but since it becomes difficult to fabricate a nanoantenna under the conditions of this example at wavelengths less than 350 nm, 360 nm was selected as the arrangement period L1.

[0084] 4A and 4B show the results of a simulation similar to that shown in FIGS. 3A and 3B, but with a nanoantenna height of 350 nm. FIG. 4A shows the simulation results for Comparative Example 3, and FIG. 4B shows the simulation results for Comparative Example 4. The conditions for Comparative Example 3 are the same as those for Comparative Example 1 except for the nanoantenna height, and the conditions for Comparative Example 4 are the same as those for Comparative Example 2 except for the nanoantenna height. Under the specular reflection conditions shown in FIG. 4B, the proportion of light intensity within ±30° tends to be higher overall than under the Lambertian scattering conditions shown in FIG. 4A, as in the cases of FIGS. 3A and 3B.

[0085] 4B, the period at which the light intensity ratio within ±30° is highest tends to differ for each wavelength, and the period at which the ratio is highest also tended to be similar to that when the nanoantenna height was 300 nm shown in FIG. 3B. Therefore, it was found that the same nanoantenna arrangement periods L1 to L3 can be adopted even when the nanoantenna height is 350 nm.

[0086] 5A and 5B show the simulation results of the light distribution pattern (light distribution intensity distribution depending on the output angle). FIG. 5A shows the light distribution pattern of Comparative Example 5, in which the nanoantenna arrangement period is a single period of 440 nm. FIG. 5B shows the light distribution pattern of this Example. In this Example, regions with three different nanoantenna arrangement periods, arrangement period L1: 360 nm, arrangement period L2: 440 nm, and arrangement period L3: 500 nm, are provided with approximately the same area, and the height of each nanoantenna is 300 nm. The diameter of the nanoantenna is 80% of the period in both Comparative Example 5 and this Example. For Comparative Example 5, the conditions other than the arrangement period are the same as those of this Example.

[0087] 5A and 5B show the distribution of light intensity (luminous intensity) in directions of ±90°, with the direction perpendicular to the light exit surface being 0°. Also, in Figures 5A and 5B, the light intensity in each direction is normalized with the maximum light intensity of each wavelength being 100%.

[0088] In Figure 5A, the light distribution pattern differs for each wavelength. For example, the light distribution pattern of light with a wavelength of 550 nm (yellow light) tends to have high light intensity around ±20°, while the light distribution patterns of light with a wavelength of 450 nm (blue light) and light with a wavelength of 650 nm (red light) tend to have high light intensity around 0°. It is believed that such light distribution patterns cause color unevenness.

[0089] In Figure 5B, there is almost no deviation in the light distribution pattern for each wavelength, and the light distribution patterns are nearly consistent. Therefore, this example produces uniform white light. It is believed that color unevenness was reduced by dividing the upper surface 35S of the phosphor member 35 into three regions and setting the nanoantenna arrangement period in each region to arrangement periods L1 to L3, which tend to narrow the angle for each wavelength.

[0090] Figures 6A and 6B show the results of a simulation of a light distribution pattern similar to that shown in Figures 5A and 5B, with the nanoantenna height set to 350 nm. Both Figures 6A and 6B show the same trends as those in Figures 5A and 5B.

[0091] Specifically, in Fig. 6A, where the nanoantennas are arranged at a single period, the light distribution pattern differs for each wavelength. In Fig. 6B, where the nanoantennas are arranged at multiple periods in this example, the light distribution pattern is nearly consistent for each wavelength, indicating that uniform white light with little color unevenness can be obtained.

[0092] [Manufacturing method] An example of a manufacturing method for the wavelength conversion member 15 and the lighting device 100 of this embodiment will be described. First, a dielectric film is formed on the upper surface of a flat phosphor plate by electron beam evaporation or sputtering. The material of the dielectric film is the same as the material of the nanoantenna, and is preferably a material with a high refractive index, such as TiO2, to increase the scattering intensity. The thickness of the dielectric film at this time corresponds to the height H of the nanoantennas 37A to 37C.

[0093] Next, a metal film made of aluminum (Al) is formed on the dielectric film, and a resin resist is applied to the metal film to form a resist film. The nanoantenna pattern is formed by nanoimprinting. A resin nanoimprinting mold (replica mold) with multiple holes corresponding to the shape and dimensions of the nanoantenna is pressed against the resist film and then peeled off, thereby patterning the resist film. A master mold is created on, for example, a silicon substrate by electron beam lithography, and a replica mold is created from the master mold by nanoimprinting.

[0094] For example, by using a master mold in which pillar patterns with different diameters and arrangement periods are provided for each region, it is possible to form a pattern of multiple nanoantenna groups arranged at different arrangement periods. Specifically, a master mold is used in which nanoantenna patterns with arrangement periods L1 to L3 are formed in predetermined regions corresponding to regions AR1 to AR3.

[0095] Next, dry etching is performed using the patterned resist film as a mask to etch the metal film, thereby forming a metal mask for etching the dielectric film.

[0096] Next, the dielectric film on which the metal mask is formed is etched by dry etching. For example, if the metal film is made of Al and the dielectric film is made of TiO2, etching gases of chlorine (Cl) and argon (Ar) are used for the metal film, and etching gases of carbon tetrafluoride (CF4), Ar, and oxygen (O2) are used for the dielectric film.

[0097] By removing the metal mask remaining after the above process by dry etching or wet etching, the nanoantennas 37A to 37C having different arrangement periods can be formed.

[0098] Thereafter, a protective resist is applied to the surface of the phosphor plate on which the nanoantennas are formed, and the phosphor plate is cut into individual pieces by dicing to the desired size of the phosphor member 35 (1 mm square in this embodiment).

[0099] The surface opposite the resist surface of the individualized phosphor plate, i.e., phosphor member 35, is fixed to a support substrate, and a dielectric multilayer film 41 is formed on the side surface (cut end surface) by atomic layer deposition (ALD).

[0100] As mentioned above, the dielectric material has a low refractive index such as silicon oxide (SiO2) or alumina (Al2O3), and a high refractive index such as titanium oxide (TiO2), zirconia (ZrO2), niobium pentoxide (Nb2O5), lanthanum oxide (La2O3), tantalum oxide (Ta2O5), or hafnium oxide (HfO2), which have low absorption.

[0101] Thereafter, a metal reflective film is formed on the surface of the dielectric multilayer film 41 by electron beam evaporation or sputtering. As the metal material, aluminum (Al) or silver (Ag), which have high reflectivity, is preferable. Furthermore, from the viewpoint of forming a metal film with a uniform thickness on the side surface (end surface) of the phosphor member 35, it is preferable to form the film by sputtering. In this manner, the wavelength conversion member 15 including the nanoantennas 37A to 37C and the reflective member 39 can be manufactured.

[0102] Thereafter, the protective resist for the nanoantenna is removed, the phosphor member 35 is removed from the support substrate, and the phosphor member 35 is bonded to the upper surface of the substrate 17 of the light-emitting element 13. The phosphor member 35 may be bonded to the substrate 17 via a transparent resin, or may be directly bonded by plasma activated bonding or surface activated bonding. In this manner, the lighting device 100 can be manufactured.

[0103] As described above, after the phosphor plate is divided into individual pieces, it may be bonded to the upper surface of the substrate 17 of the light emitting element 13 before forming the reflective member 39, and then the dielectric multilayer film 41 and the metal film 43 may be formed on the side surfaces of the light emitting element 13 and the phosphor member 35. In this way, it is possible to manufacture the lighting device 100 in which the reflective member 39 is also formed on the side surfaces of the substrate and semiconductor layer of the light emitting element 13 as shown in FIG.

[0104] In this embodiment, an example has been described in which wavelength conversion member 15 has three regions AR1 to AR3, and a region having one type of nanoantenna period is provided within one region, but this is not limiting. In wavelength conversion member 15, a region having one type of nanoantenna period may be provided in multiple regions. For example, multiple regions AR1, multiple regions AR2, and multiple regions AR3 may be provided in a matrix.

[0105] In this embodiment, the area ratios S1 to S3 of the regions AR1 to AR3 to the area of ​​the upper surface 35S of the phosphor member 35 are all set to 1 / 3, but this is not limited to this. By changing the area ratio, it is possible to change the emission intensity of light of each target wavelength and adjust the color. The higher the area ratio, the higher the light intensity within ±30° of the light of the corresponding wavelength.

[0106] For example, by making the area ratio S3 of the region AR3 larger than the area ratios S1 and S2 of the regions AR1 and AR2, respectively, the light intensity of the red light can be increased. For example, as described above, when the red light component is insufficient due to the properties of the YAG:Ce phosphor, by increasing the area ratio S3, for example, it is possible to obtain white light with high visibility that is close to blackbody radiation. This makes it possible to satisfy the specifications for the red light component of, for example, an automobile headlamp.

[0107] Furthermore, for example, when it is not necessary to actively extract the red light component, it is possible to provide only two types of regions, regions AR1 and AR2, and not provide region AR3.

[0108] As described above, the wavelength conversion member 15 of this embodiment includes a flat phosphor member 35 containing a phosphor that emits fluorescence when excited by excitation light, a reflecting member that is provided on a side surface 35E of the phosphor member 35 and reflects the excitation light and fluorescence, and a plurality of nanoantennas made of a metal material or a dielectric material that are provided on a top surface 35S that is one main surface of the phosphor member. In a plan view seen from a direction perpendicular to the top surface 35S, the plurality of nanoantennas are arranged in a lattice pattern at arrangement periods L1 to L3 that are determined for each of regions AR1 to AR3 on the top surface 35S.

[0109] The arrangement periods in the regions AR1 to AR3 correspond to wavelengths of 450 nm, 550 nm, and 650 nm, respectively, included in the wavelength ranges of the excitation light and fluorescence, and these wavelengths are wavelengths included in multiple non-overlapping wavelength bands.

[0110] In other words, the nanoantennas of this embodiment include a plurality of nanoantenna groups having mutually different arrangement periods. Specifically, the nanoantennas of this embodiment include a first nanoantenna group in which a plurality of nanoantennas 37A are arranged in a lattice pattern with an arrangement period L1 as a first arrangement period, a second nanoantenna group in which a plurality of nanoantennas 37B are arranged in a lattice pattern with an arrangement period L2 as a second arrangement period, and a third nanoantenna group in which a plurality of nanoantennas 37C are arranged in a lattice pattern with an arrangement period L3 as a third arrangement period.

[0111] In this embodiment, the arrangement period L1 corresponds to a wavelength of 450 nm as a first wavelength, which is a wavelength selected from a wavelength band of 430 nm or more and 470 nm or less as a first wavelength band.

[0112] The arrangement period L2 corresponds to a wavelength of 550 nm, which is a second wavelength included in the wavelength range of the excitation light and the fluorescence. The second wavelength is a wavelength selected from the second wavelength band of 530 nm to 570 nm.

[0113] The arrangement period L3 corresponds to a wavelength of 650 nm, which is a third wavelength included in the wavelength range of the excitation light and the fluorescence. The third wavelength is a wavelength selected from a third wavelength band of 600 nm to 700 nm.

[0114] The region AR1, which is the first region, is the region where the first nanoantenna group is formed on the top surface 35S, which is one of the main surfaces of the phosphor member 35. Of the light emitted from the first region, the intensity ratio of the light emitted within a predetermined angle range centered on the direction perpendicular to the top surface of the phosphor member 35 is such that the light of the first wavelength is greater than the light of the second wavelength, and the light of the first wavelength is greater than the light of the third wavelength.

[0115] Furthermore, the region where the second nanoantenna group is formed is a region AR2 as a second region on the upper surface 35S of the phosphor member 35. With regard to the intensity ratio of the light emitted from the second region within a predetermined angle range centered on the direction perpendicular to the upper surface 35S of the phosphor member 35, the light of the second wavelength has a higher intensity than the light of the first wavelength, and the light of the second wavelength has a higher intensity than the light of the third wavelength.

[0116] Furthermore, the region where the third nanoantenna group is formed is a region AR3 as a third region on the upper surface 35S of the phosphor member 35. With regard to the intensity ratio of the light emitted from the third region within a predetermined angle range centered on the direction perpendicular to the upper surface 35S of the phosphor member 35, the light of the third wavelength has a higher intensity than the light of the first wavelength, and the light of the third wavelength has a higher intensity than the light of the second wavelength. .

[0117] The lighting device of this embodiment has a configuration in which a light emitting element 13 flip-chip mounted on a mounting substrate is used as a light source, and the wavelength conversion member 15 of this embodiment is bonded onto a substrate 17 of the light emitting element 13. Specifically, the lower surface of the phosphor member 35, which is the surface opposite to the upper surface on which the nanoantenna is formed, is bonded onto the substrate 17.

[0118] With the above-described configuration, when the light distribution pattern of the lighting device of this embodiment is viewed for each wavelength corresponding to the arrangement period of the nanoantennas in each nanoantenna group, the phenomenon in which the light distribution pattern differs for each wavelength, as seen in the case of a single period, is mitigated, and a narrow-angle light distribution with little color unevenness is obtained.

[0119] In this example, an example has been described in which first to third nanoantenna groups are provided with periods corresponding to wavelengths of 450 nm, 550 nm, and 650 nm, which have different colors and are included in the wavelength ranges of the excitation light and the fluorescence, but the wavelength conversion member of the present invention is not limited to this. It is sufficient that the wavelength conversion member includes at least two nanoantenna groups.

[0120] For example, as described above, two nanoantenna groups may be provided at periods corresponding to wavelengths of 450 nm and 550 nm, respectively, or two nanoantenna groups may be provided at periods corresponding to wavelengths of 550 nm and 650 nm.

[0121] In other words, in the wavelength conversion member of the present invention, the multiple nanoantennas include a first group of nanoantennas arranged in a lattice pattern with a first arrangement period, and a second group of nanoantennas arranged in a lattice pattern with a second arrangement period.

[0122] The first array period is a period corresponding to a first wavelength included in the wavelength range of the excitation light and the fluorescence, and the second array period is a period corresponding to a second wavelength included in the wavelength range of the excitation light and the fluorescence.

[0123] For example, the first wavelength may be 450 nm corresponding to blue light, and the second wavelength may be 550 nm corresponding to yellow light. In other words, the first wavelength may be selected from a first wavelength band, and the second wavelength may be selected from a second wavelength band.

[0124] Alternatively, the first wavelength may be 550 nm corresponding to yellow light, and the second wavelength may be 650 nm corresponding to red light, or the first wavelength may be selected from the second wavelength band, and the second wavelength may be selected from the third wavelength band.

[0125] The intensity ratio of light emitted from the first region where the first nanoantenna group is formed on the top surface 35S, which is one of the main surfaces of the phosphor member 35, within a predetermined angular range centered on a direction perpendicular to the top surface 35S is such that the light of the first wavelength is greater than the light of the second wavelength.

[0126] Furthermore, the intensity ratio of light emitted from the second region on the upper surface 35S of the phosphor member 35 where the second nanoantenna group is formed within a predetermined angular range centered on a direction perpendicular to the upper surface 35S is greater for light of the second wavelength than for light of the first wavelength.

[0127] The above configuration provides a narrow-angle light distribution, high output, and mixed-color light with minimal color unevenness. For example, by selecting the arrangement period of at least two nanoantenna groups as described above according to the desired chromaticity, white light of the desired color can be obtained.

[0128] Therefore, according to this embodiment, it is possible to provide a wavelength conversion member that can constitute an illumination device with a narrow light angle, high output, and little color unevenness, and an illumination device using the same.

[0129] As described above, the inventors of the present application discovered that when mixing light of a wide wavelength range including light of different colors, the tendency for the period of nanoantennas, which are prone to narrowing the angle, to vary depending on the wavelength, becomes more pronounced by providing a reflective member that causes specular reflection. Then, to make each of the multiple wavelengths of light of different colors more susceptible to diffraction by the nanoantennas, multiple regions are provided on the upper surface of the wavelength conversion member, and nanoantennas arranged at multiple arrangement periods are provided in each of the different regions. This reduces the difference in light distribution pattern for each wavelength, resulting in mixed color light with less color unevenness.

[0130] In this embodiment, the reflective member 39 is formed of the dielectric multilayer film 41 formed to cover the side surfaces of the phosphor member 35 and the metal film 43 formed on the dielectric multilayer film 41, but is not limited to this. For example, the reflective member 39 may be only the dielectric multilayer film 41 covering the side surfaces of the phosphor member 35, or only the metal film 43 covering the side surfaces of the phosphor member 35.

[0131] Even in this way, the lighting device 100 can achieve the effect of the present invention, in which the differences in light distribution patterns for each wavelength are mitigated by multiple nanoantenna groups with different arrangement periods, and mixed color light with a narrow light angle, high output, and little color unevenness is emitted.

[0132] The reflecting member 39 is a member (also referred to as a specular reflecting member) that generates a certain amount of what is generally called specularly reflected components when reflecting light that has reached the side surface of the phosphor member 35. For example, the reflecting member 39 is a member in which the specularly reflected component is the main component of the reflected light.

[0133] In other words, the present invention does not assume that the reflective member 39 is made entirely of a material that causes diffuse reflection, such as a member made entirely of white resin.

[0134] It should be noted that even if a portion of the reflective member 39 contains a portion that causes diffuse reflection, such as white resin, it is acceptable as long as a certain level of regular reflection component is generated overall. For example, instead of the metal film 43, a resin member made of white resin may be formed on the dielectric multilayer film 41 to form the reflective member 39. For example, the white resin may be silicone resin with titanium oxide (TiO2) dispersed therein.

[0135] As described above with respect to the simulations of Figures 3A and 3B, the proportion of light extracted at a narrow angle is greater when the rear and side surfaces of the phosphor member 35 are ideal specular reflecting surfaces than when they are Lambertian scattering surfaces.

[0136] In the configuration of this embodiment having the reflective member 39, from the viewpoint of increasing the light flux extracted at a narrow angle, we investigated using a simulation of a comparative example what the desired specular reflectance of light reaching the side surface of the phosphor member 35 should be.

[0137] As a result of our investigation, we have concluded that it is preferable that the specular reflectance of the side surface of the fluorescent member is 80% or more. If the specular reflectance of the side surface of the fluorescent member is 80% or more, we have concluded that the light extraction efficiency within an emission angle of ±30° can be increased to a level equal to or greater than that when the reflection mode on the back surface and side surface is diffuse reflection. The details of our investigation are explained below.

[0138] Specifically, the light extraction efficiency within ±30° was calculated from the light extraction efficiency and the proportion of luminous flux within ±30°, and the luminous flux extracted at a narrow angle was evaluated using the light extraction efficiency within ±30°. In other words, the evaluation and study were conducted assuming that the higher the light extraction efficiency within ±30° (hereinafter also referred to as narrow-angle extraction efficiency) is, the higher the luminous flux extracted at a narrow angle is. The light extraction efficiency was defined as the proportion of the total luminous flux of light emitted from the wavelength conversion member to the radiant intensity of the light-emitting element.

[0139] The light extraction efficiency was calculated by a simulation using the RCWA (Rigorous Coupled Wave Analysis) method and ray tracing. The lighting device conditions (model) used in the simulation were as follows: The phosphor member was a single-phase transparent ceramic phosphor plate made of yttrium-aluminum-garnet (YAG:Ce) phosphor with cerium (Ce) as an activator, and the nanoantenna was made of titanium dioxide. The size of the phosphor member was 1 mm square and 0.1 mm thick. The nanoantennas were arranged in a triangular lattice pattern with a period of 420 nm, had a cylindrical shape, and their particle diameter was 80% of the period. The calculation was performed assuming a light wavelength of 550 nm. The configurations of the light-emitting element and reflector were the same as in Example 1.

[0140] Fig. 7 is a graph showing the results of a simulation in which the light extraction efficiency was calculated for this model when the specular reflectance of the back surface of the phosphor member was fixed at 92% (8% is absorption) and the specular reflectance of the side surfaces was changed from 80% to 100%. The light extraction efficiency in Fig. 7 is shown as 100%, based on the light extraction efficiency when the diffuse reflectance of the back surface is 92% (8% is absorption) and the specular reflectance of the side surfaces is 100%.

[0141] The condition of a diffuse reflectance of 92% on the rear surface and a specular reflectance of 100% on the side surfaces is the condition under which the light extraction efficiency is maximized in a practical configuration of this example, and was therefore used as the standard for this study.

[0142] 3A and 3B, data for the condition where the light wavelength λ is 550 nm and the nanoantenna pitch is 420 nm was used as the luminous flux ratio within ±30°. As described above, Fig. 3A shows the light intensity ratio (i.e., luminous flux ratio) within ±30° when the side and back surfaces of the phosphor member 35 are Lambertian scattering surfaces (Lambertian scattering condition).

[0143] The Lambertian scattering condition in Fig. 3A is the condition under which the light extraction efficiency is approximately equal to the reference condition for the light extraction efficiency in this study, i.e., the condition of a diffuse reflectance of 92% on the back surface and a specular reflectance of 100% on the side surfaces. Therefore, here, the light extraction efficiency for λ = 550 nm and a period of 420 nm in Fig. 3A is also set to 100%.

[0144] 3A, the luminous flux ratio within ±30° at a wavelength λ of 550 nm and a period of 420 nm is approximately 31%. In this case, the light extraction efficiency within an emission angle of ±30° (narrow angle extraction efficiency) is 31%, which is obtained by multiplying the light extraction efficiency (100%) by the luminous flux ratio within ±30° (31%).

[0145] 3B shows the luminous flux ratio within ±30° when the side and back surfaces of the phosphor member 35 are ideal specular reflection surfaces (specular reflection conditions). From FIG. 3B, the luminous flux ratio within ±30° when the wavelength λ is 550 nm and the period is 420 nm is approximately 41%. In this study, the luminous flux ratio within ±30° of the above model is treated as being constant at approximately 41%, which is equivalent to the case of an ideal specular reflection surface, regardless of the specular reflectance of the side surfaces.

[0146] In this simulation, the side and back surfaces of the model phosphor member 35 are not ideal specular reflection surfaces, but are surfaces where specular reflection is dominant, and are therefore referred to as specular reflection surfaces. In contrast, surfaces where diffuse reflection of reaching light is dominant, including Lambertian scattering surfaces, are also referred to as diffuse reflection surfaces.

[0147] The light extraction efficiency (narrow-angle extraction efficiency) within an emission angle of ±30° for the above model is calculated to be approximately 75% when the side and back surfaces of the phosphor member 35 are Lambertian scattering surfaces, which is equivalent to the narrow-angle extraction efficiency (31%). From Figure 7, it can be said that the side specular reflectance at which the light extraction efficiency is approximately 75% is approximately 80%. Table 1 shows the luminous flux ratio within ±30°, light extraction efficiency, and narrow-angle extraction efficiency for each condition of the Lambertian scattering surface and the simulation model when the narrow-angle extraction efficiency is equivalent.

[0148] [Table 1]

[0149] In other words, it has been confirmed that the luminous flux ratio within ±30° when the period is 420 nm in Figure 3 is approximately 75% of that when the side and back surfaces of the phosphor member are Lambertian scattering surfaces (i.e., diffuse reflection surfaces) (31%) and that when the side and back surfaces are specular reflection surfaces (41%). Therefore, according to the correspondence relationship in Table 1, when the light extraction efficiency in the case of specular reflection is approximately 75% of that in the case of diffuse reflection (100%), the extraction efficiency within ±30° is equivalent. The side specular reflectance in this case is approximately 80% as shown in Figure 7. Therefore, by having a side specular reflectance of 80% or more, it is possible to increase the luminous flux within ±30° to a level equal to or greater than that when the side and back surfaces are diffuse reflection surfaces.

[0150] Furthermore, to increase the specular reflection component, it is desirable that the side and back surfaces of the phosphor member 35 are mirror surfaces. If the surface roughness Ra, which is the standard for a typical mirror finish, is 0.2 μm or less, the specular reflection component can be increased to, for example, a specular reflectance of approximately 92%.

[0151] The reflecting member 39 may be configured so that the specular reflecting member covers at least a portion of the side surface of the phosphor member 35. For example, the reflecting member 39 may be configured so that the dielectric multilayer film 41 covers a portion of the side surface of the phosphor member 35, the metal film 43 is formed on the dielectric multilayer film 41, and a portion made of white resin that covers the remaining portion of the side surface of the phosphor member 35. Even in this case, the reflecting member 39 as a whole may be configured so that a certain amount or more of specularly reflected components are generated. [Example]

[0152] 8 is a top view of a lighting device 200 including a wavelength conversion member 51 according to a second embodiment of the present invention. The lighting device 200 is configured similarly to the lighting device 100 of the first embodiment, except that it has a wavelength conversion member 51 instead of the wavelength conversion member 15. The wavelength conversion member 51 is configured similarly to the wavelength conversion member 15 of the first embodiment, except for the arrangement period and arrangement mode of the nanoantennas.

[0153] In wavelength conversion member 51, the blue light emitted from upper surface 35S of phosphor member 35 is blue light that has not been excited, i.e., not absorbed, by the phosphor, and therefore the light intensity of the blue light can be adjusted by changing the thickness of the phosphor. Specifically, the light intensity of the blue light can be increased by reducing the thickness of the phosphor.

[0154] Furthermore, blue light tends to have a relatively narrow light distribution angle because light with a short optical path length and an emission angle of 0° tends to be easily extracted from the top surface 35S. In other words, it can be said that the light intensity within ±30° can be adjusted by the thickness of the phosphor member 35, without narrowing the angle using a nanoantenna.

[0155] Therefore, in this embodiment, blue light is not the target of angle narrowing by the nanoantenna, and two wavelengths corresponding to the wavelengths of yellow light and red light are the target wavelengths of angle narrowing by the nanoantenna. As in Example 1, the target wavelength included in the wavelength range of yellow light is set to 550 nm, and the array period L2 that easily diffracts light with a wavelength of 550 nm is set to 440 nm. Furthermore, the target wavelength included in the wavelength range of red light is set to 650 nm, and the array period L3 that easily diffracts light with a wavelength of 650 nm is set to 500 nm.

[0156] 8, the wavelength conversion member 51 has two regions on the upper surface 35S of the phosphor member 35: a region AR2 where nanoantennas 37B are arranged at an arrangement period L2, and a region AR3 where nanoantennas 37C are arranged at an arrangement period L3. The area ratios S2 and S3 of the region AR2 and the region AR3 to the entire region where the nanoantennas are formed are both 1 / 2.

[0157] The lighting device 200 including the wavelength conversion member 51 of this embodiment provides a narrow-angle light distribution pattern with high light intensity within ±30° and white light with little color unevenness. In the example shown in Fig. 8, the area ratios S2 and S3 are both set to 1 / 2, but this is not limiting, and the color of the mixed color light may be adjusted by increasing either area ratio. For example, by making the area ratio S3 of the region AR3 corresponding to red light larger than the area ratio S2 of the region AR2 corresponding to yellow light, white light containing a sufficient amount of red light can be obtained.

[0158] 9 is a top view of a lighting device 201 including a wavelength conversion member 61 according to Modification 1 of Example 2. The wavelength conversion member 61 has the same configuration as the wavelength conversion member 51 of Example 2, except for the arrangement period and arrangement mode of the nanoantennas.

[0159] 9, in the present modified example 1, the regions AR2 and AR3 are each divided into two and arranged in a matrix when viewed from above the wavelength conversion member 61. In other words, the region AR2 as a first region and the region AR3 as a second region are arranged in a matrix when viewed from a direction perpendicular to the upper surface 35S of the phosphor member 35. By arranging the regions AR2 and AR3 in this manner, color unevenness can be reliably reduced.

[0160] 9, when one type of region, i.e., a region in which nanoantenna groups with the same arrangement period are formed, is divided into multiple regions, the area ratio of one type of region to the entire region in which nanoantennas are formed is the ratio of the total area of ​​each of the multiple divided regions. For example, the area ratio S2 of region AR2 is the ratio of the total area of ​​the multiple regions AR2. In the example shown in FIG. 9, the area ratio S2 of region AR2 and the area ratio S3 of region AR3 are equal, and both are 1 / 2 (S2 = S3).

[0161] Note that each of the regions AR2 and AR3 is not limited to being divided into two, but may be divided into three or more regions and arranged in a matrix. However, from the viewpoint of narrow-angle light distribution, a configuration with fewer boundaries between regions is preferable because it allows the narrow angle to be maintained.

[0162] 10 is a top view of a lighting device 202 including a wavelength conversion member 71 according to Modification 2 of Example 2. The wavelength conversion member 71 has the same configuration as the wavelength conversion member 51 of Example 2, except for the arrangement period and arrangement mode of the nanoantennas.

[0163] 10 , in the present modified example 2, the region AR2 and the region AR3 are concentrically arranged in a top view of the wavelength conversion member 71. In other words, the region AR2 as the first region and the region AR3 as the second region are concentrically arranged in a plan view seen from a direction perpendicular to the top surface 35S of the phosphor member 35. By arranging the areas AR2 and AR3 in this way, it is possible to reliably reduce color unevenness. Note that, although an example in which the area AR3 is arranged inside the area AR2 is shown in Figure 10, this is not limiting, and either area may be arranged inside.

[0164] 10, when the phosphor member 35 is singulated after the nanoantennas are formed, the cutting positions are all at the boundaries between regions with the same nanoantenna arrangement period. Therefore, even if variations occur in the cutting positions, the impact is smaller than when cutting at the boundaries between regions with different nanoantenna arrangement periods, and the yield can be increased.

[0165] The configurations in the above-described embodiments and modifications are merely examples, and can be modified or combined as appropriate depending on the application, etc.

[0166] For example, in the above-described embodiments and modifications, the conditions such as the arrangement period of the nanoantennas, the arrangement of the regions in which the nanoantenna groups are arranged, and the area ratio of each region are not limited to the above-described examples, and can be appropriately adjusted according to the wavelength of the light emitted from the light source, the desired light distribution, the desired color, etc. Furthermore, the arrangement pattern of the nanoantennas is not limited to the above-described triangular lattice shape, and may be, for example, a square lattice shape. [Explanation of symbols]

[0167] 100, 200 lighting equipment 11 Mounting board 13 Light-emitting element 15 Wavelength conversion device 17 Sapphire substrate 19 n-type semiconductor layer 21 Active layer 23 p-type semiconductor layer 25 Semiconductor laminate 27p electrode 29 p-type electrode pad 31 n electrode 33 n-type electrode pad 35 Phosphor materials 37A, 37B, 37C Nanoantennas 39 Reflective material 41 Dielectric multilayer film 43 Metal Film

Claims

1. a flat-plate phosphor member containing a phosphor that emits fluorescence when excited by excitation light; a reflecting member provided on a side surface of the phosphor member and reflecting the excitation light and the fluorescent light; a plurality of nanoantennas formed on one main surface of the phosphor member and made of a metal material or a dielectric material; the plurality of nanoantennas include a first group of nanoantennas arranged in a lattice pattern with a first arrangement period and a second group of nanoantennas arranged in a lattice pattern with a second arrangement period; the first arrangement period is a period corresponding to a first wavelength included in a wavelength range of the excitation light and the fluorescence, the second array period is a period corresponding to a second wavelength included in the wavelength range of the excitation light and the fluorescence, an intensity ratio of light emitted from a first region in which the first nanoantenna group is formed in the phosphor member within a predetermined angular range centered on a direction perpendicular to the main surface is such that the intensity ratio of light having the first wavelength is greater than the intensity ratio of light having the second wavelength; A wavelength conversion member characterized in that the intensity ratio of light emitted from a second region in which the second nanoantenna group is formed in the phosphor member within a predetermined angular range centered on a direction perpendicular to the main surface is greater for light of the second wavelength than for light of the first wavelength.

2. the excitation light has a peak wavelength of 430 nm or more and 470 nm or less, the fluorescence has a peak wavelength of 520 nm or more and 570 nm or less and a base wavelength of 600 nm or more and 700 nm or less, 2. The wavelength conversion member according to claim 1, wherein the first wavelength and the second wavelength are included in different wavelength bands selected from a first wavelength band of 430 nm to 470 nm, a second wavelength band of 530 nm to 570 nm, and a third wavelength band of 600 nm to 700 nm.

3. The wavelength conversion member according to claim 2 , wherein the first wavelength is selected from the first wavelength band, and the second wavelength is selected from the second wavelength band.

4. The wavelength conversion member according to claim 2 , wherein the first wavelength is selected from the second wavelength band, and the second wavelength is selected from the third wavelength band.

5. the plurality of nanoantennas includes a third group of nanoantennas arranged at a third arrangement period; the third arrangement period is a period corresponding to a third wavelength included in the wavelength range of the excitation light and the fluorescence, the first wavelength is selected from the first wavelength band, the second wavelength is selected from the second wavelength band, and the third wavelength is selected from the third wavelength band; an intensity ratio of the light emitted from the first region within a predetermined angle range centered on a direction perpendicular to the main surface is such that the light of the first wavelength is greater than the light of the second wavelength or the light of the third wavelength; an intensity ratio of the light emitted from the second region within a predetermined angle range centered on a direction perpendicular to the main surface is such that the light of the second wavelength is greater than the light of the first wavelength or the light of the third wavelength; an intensity ratio of light having the third wavelength emitted from a third region in which the third nanoantenna group is formed in the phosphor member within a predetermined angular range centered on a direction perpendicular to the main surface is greater than an intensity ratio of light having the third wavelength compared to light having the first wavelength or second wavelength; 3. The wavelength conversion member according to claim 2, wherein the area of ​​the third region is larger than the area of ​​the first region and the area of ​​the second region.

6. 2. The wavelength conversion member according to claim 1, wherein the first region and the second region are strip-shaped regions each arranged along a direction perpendicular to the first main surface of the phosphor member in a planar view.

7. 2. The wavelength conversion member according to claim 1, wherein the first regions and the second regions are arranged in a matrix in a plan view seen from a direction perpendicular to the first main surface of the phosphor member.

8. 2. The wavelength conversion member according to claim 1, wherein the first region and the second region are concentrically arranged in a plan view seen from a direction perpendicular to the first main surface of the phosphor member.

9. 2. The wavelength conversion member according to claim 1, wherein each of the plurality of nanoantennas has a maximum width of 75% to 85% of the first arrangement period in the first region, and a maximum width of 75% to 85% of the second arrangement period in the second region, when viewed in a planar view from a direction perpendicular to the first main surface of the phosphor member.

10. 2. The wavelength conversion member according to claim 1, wherein the reflecting member comprises a multilayer film reflector formed on the side surface and a metal film formed on the multilayer film reflector.

11. The wavelength conversion member according to claim 1 ; a light source including a substrate and a semiconductor laminate formed on the substrate in this order: a first semiconductor layer having a first conductivity type, an active layer, and a second semiconductor layer having a second conductivity type different from the first conductivity type; The substrate is translucent to light emitted from the active layer, and is bonded to a surface of the phosphor member opposite to the first main surface.

12. The lighting device according to claim 11 , wherein the reflecting member is provided on a side surface of the substrate and a side surface of the semiconductor laminate.

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