Wavelength conversion member and lighting device using same

Abstract

The present invention has: a flat plate-shaped phosphor portion including a phosphor that is excited by excitation light and emits fluorescent light; and a plurality of nano antennas disposed to form a lattice-like array pattern in each of a plurality of regions on the one surface in a plan view viewed from a direction perpendicular to the surface of the phosphor portion, and configured of a metal material or a dielectric material, the plurality of nano antennas being disposed to form a lattice-like array pattern in each of the plurality of regions on the one surface, the plurality of nano antennas being disposed to form a lattice-like array pattern in each of the plurality of regions on the one surface, and the plurality of nano antennas being disposed to form a lattice-like array pattern in each of the plurality of regions. The array pattern of the plurality of nano-antennas in one region among the plurality of regions is a pattern obtained by rotating the array pattern of the plurality of nano-antennas in another region about an axis perpendicular to a single plane.

Description

Technical Field

[0001] This invention relates to wavelength conversion components and lighting devices using wavelength conversion components. Background Technology

[0002] A device for collimating emitted light using nanoscale antennas (hereinafter referred to as nanoantennas) has been disclosed. For example, Patent Document 1 discloses an illumination device having a light source emitting blue light, a phosphor layer excited by light emitted from the light source to generate fluorescence, and a plurality of nanoantennas arranged in a grid shape on the upper surface of the phosphor layer.

[0003] References

[0004] Patent documents

[0005] Patent Document 1: JP-A 2018-13688 Summary of the Invention

[0006] The problem to be solved by the present invention

[0007] For example, when a screen arranged separately from the lighting device, as in Patent Document 1, is illuminated by light emitted from the lighting device, the fluorescence components in a certain wavelength range emitted from the phosphor layer are significantly enhanced due to the action of the nanoantenna, resulting in uneven color in the light illuminating the screen.

[0008] The present invention was made in consideration of the above-mentioned problems, and its object is to provide a wavelength conversion device and an illumination device capable of suppressing color inhomogeneity in light emitted via nanoantennas.

[0009] Solution to the problem

[0010] The wavelength conversion device according to the present invention includes a planar phosphor portion and a plurality of nanoantennas. The planar phosphor portion contains a phosphor that is excited by excitation light to produce fluorescence. When viewed from a direction perpendicular to one face of the phosphor portion, the plurality of nanoantennas are arranged in a planar view to form a grid-like array pattern in each of a plurality of regions on said one face. The plurality of nanoantennas are made of a metallic or dielectric material. The array pattern of the plurality of nanoantennas in one of the plurality of regions is obtained by rotating the array pattern of the plurality of nanoantennas in another region about an axis perpendicular to said one face. Attached Figure Description

[0011] Figure 1 This is a top view of the lighting device according to Embodiment 1.

[0012] Figure 2This is a cross-sectional view of the lighting device according to Embodiment 1.

[0013] Figure 3 This diagram schematically illustrates a state in which a screen is illuminated by light emitted from the lighting device according to Embodiment 1.

[0014] Figure 4 This is a graph illustrating various diffraction lines as the emission angle of the fluorescence emitted from the phosphor portion in the lighting device according to Embodiment 1 changes.

[0015] Figure 5 It is a graph illustrating visual sensitivity to light within the wavelength range of visible light.

[0016] Figure 6 This is a top view of a lighting device according to a modified embodiment 1.

[0017] Figure 7 This is a cross-sectional view of the lighting device according to Embodiment 2.

[0018] Figure 8 This is an example of a graph showing the reflectivity of the dielectric multilayer film for visible light in the lighting device according to Embodiment 2.

[0019] Figure 9 This is a graph illustrating the excitation spectrum of phosphors in the phosphor portion. Detailed Implementation

[0020] Embodiments of the present invention will now be described in detail with reference to the accompanying drawings. Note that in the drawings, the same reference numerals are given for the same parts, and descriptions of repeated parts are omitted.

[0021] Implementation Method 1

[0022] [Lighting device according to embodiment 1]

[0023] use Figure 1 and Figure 2 The structure of the lighting device 100 according to Embodiment 1 is described. Figure 1 This is a top view of the lighting device 100 according to Embodiment 1. Figure 2 It is along Figure 1 The cross-sectional view of the lighting device 100 taken from line 2-2. Note that... Figure 1 The horizontal direction in the text refers to the width direction of the lighting device 100, and Figure 2 The vertical direction in the diagram is the height direction of the lighting device 100.

[0024] The lighting device 100 is configured to include a mounting plate 11, a light-emitting element 12 including a light-emitting layer disposed on the mounting plate 11, and a wavelength conversion device 13 disposed on the light-emitting element 12 and including a phosphor portion that generates fluorescence when receiving light emitted from the light-emitting layer.

[0025] [Mounting plate]

[0026] First, the mounting plate 11 is described. The mounting plate 11 is a flat plate with a rectangular upper surface. The mounting plate 11 is made, for example, of materials with high thermal conductivity and electrical insulation properties (such as aluminum nitride (AlN) and aluminum oxide). It is made of a material that can efficiently release the heat generated when driving the light-emitting element 12.

[0027] [Light-emitting element]

[0028] Next, the structure of the light-emitting element 12, which serves as the light source, will be described. The light-emitting element 12 is a light-emitting diode (LED) disposed on the upper surface of the mounting plate 11 and having a rectangular upper surface shape.

[0029] The light-emitting element 12 is configured to include: a semiconductor structure layer 15 having a light-emitting layer, a support substrate 16 disposed on the upper surface of the semiconductor structure layer 15, and a p electrode 17 and an n electrode 18 disposed on the lower surface of the semiconductor structure layer 15 and bonded to the mounting plate 11. That is, the light-emitting element 12 is flip-chip mounted on the mounting plate 11.

[0030] The semiconductor structure layer 15 is a semiconductor laminate composed of an n-type semiconductor layer, a light-emitting layer, and a p-type semiconductor layer (none shown) (each of which contains gallium nitride (GaN) as the main material). When the light-emitting element 12 is driven, blue light with a peak wavelength of 450 nm is emitted from the light-emitting layer of the semiconductor structure layer 15.

[0031] The support substrate 16 is a flat plate with a rectangular upper surface. The support substrate 16 is made of a material that is translucent relative to the blue light emitted from the light-emitting layer of the semiconductor structure layer 15 (such as sapphire). It is made of GaN. The upper surface of the support substrate 16 is the light-emitting surface when blue light is emitted from the light-emitting layer of the semiconductor structure layer 15 by the light-emitting element 12.

[0032] p electrode 17 is an electrode electrically connected to the p-type semiconductor layer of the semiconductor structure layer 15. p electrode 17 is bonded to a p-side wiring (not shown) formed on the upper surface of the mounting plate 11 via a conductive bonding member (not shown).

[0033] The n-electrode 18 is an electrode that penetrates vertically through the light-emitting layer and the p-type semiconductor layer of the semiconductor structure layer 15 and is electrically connected to the n-type semiconductor layer via a through electrode (not shown) whose side surface is covered with an insulator. In other words, the n-electrode 18 is only electrically connected to the n-type semiconductor layer and is insulated from the light-emitting layer and the p-type semiconductor layer. The n-electrode 18 is bonded to an n-side wiring (not shown) formed on the upper surface of the mounting plate 11 via a conductive bonding member (not shown).

[0034] Wavelength conversion device

[0035] Next, the structure of the wavelength conversion device 13 will be described. The wavelength conversion device 13 is a device that has the function of generating fluorescence with different wavelengths when receiving light emitted from the light-emitting element 12. The wavelength conversion device 13 is constructed to include a phosphor portion 21 and a plurality of nanoantennas 22 formed on the phosphor portion 21.

[0036] The phosphor portion 21 is a plate-shaped body with a rectangular upper surface. The phosphor portion 21 is disposed on the upper surface of the support substrate 16 of the light-emitting element 12 so as to overlap with the outer edge of the support substrate 16 in a plan view of the lighting device 100 viewed from above.

[0037] The phosphor portion 21 is made of a phosphor that is excited by blue light, which is the excitation light emitted from the light-emitting element 12, to produce fluorescence. When excited by blue light, the fluorescence produced by the phosphor has a wide green to orange wavelength range from 480 nm to 700 nm, and a yellow peak wavelength from 520 nm to 570 nm.

[0038] Phosphor portion 21 is, for example, a single-crystal transparent ceramic phosphor plate made of yttrium aluminum garnet (YAG:Ce) phosphor (in which cerium (Ce) is used as an activator).

[0039] While the phosphor portion 21 is not limited to a phosphor plate composed of single-crystal YAG:Ce phosphor, it preferably has a structure that does not easily induce internal scattering. Therefore, it is preferably a single-phase phosphor plate made of a single material, and in this case, it can be polycrystalline.

[0040] When blue light emitted from the light-emitting element 12 enters the phosphor portion 21, a portion of it passes directly through the phosphor portion 21, and another portion excites the phosphor, thereby generating fluorescence from the excited phosphor.

[0041] Therefore, excitation light that has passed through the phosphor portion 21 and does not contribute to the generation of fluorescence is emitted from the upper surface of the phosphor portion 21, and fluorescence emitted from the phosphor is emitted from the phosphor. Therefore, white light, a mixture of yellow fluorescence and blue light emitted from the upper surface of the phosphor portion 21, is emitted from the illumination device 100.

[0042] The nanoantenna 22 is a nanoscale, microscopic columnar or spin-shaped protrusion. In this embodiment, the nanoantenna 22 is a cylindrical structure formed on the upper surface of the phosphor portion 21. Multiple nanoantennas 22 are formed on the upper surface of the phosphor portion 21 and arranged at a predetermined period. The nanoantennas 22 are arranged at a period shorter than the peak wavelength of fluorescence emitted from the phosphor in the phosphor portion 21.

[0043] like Figure 1 As shown, the nanoantenna 22 is formed by dividing the upper surface of the phosphor portion 21 into three regions (first region A1, second region A2, and third region A3). In each of the three regions, the nanoantenna 22 has a triangular grid-like array pattern.

[0044] In a plan view taken from a direction perpendicular to the upper surface of phosphor portion 21, each of the first region A1, the second region A2, and the third region A3 has a strip shape, the longitudinal direction of which is Figure 1 The horizontal direction in the middle. Region A1, Region A2, and Region A3 are along... Figure 1 The vertical directions are set in this order.

[0045] The nanoantennas 22 in the first region A1 are arranged in a triangular grid pattern by arranging each of the nanoantennas 22 along the array line AL1. The array line AL1 is used as a reference line for the array patterns of the nanoantennas 22 in the second region A2 and the third region A3, which will be described later.

[0046] The nanoantennas 22 in the second region A2 are arranged in a triangular grid pattern by arranging each nanoantenna 22 along the array line AL2. The array line AL2 is at an angle to the reference line RL parallel to the array line AL1. .

[0047] In other words, the array pattern of the nanoantennas 22 in the second region A2 is obtained by rotating the array pattern of the nanoantennas 22 in the first region A1 about an axis perpendicular to the upper surface of the phosphor portion 21. The resulting pattern. In the lighting device 100, the angle... An angle other than an integer multiple of 60°, and for example, 19°.

[0048] The nanoantennas 22 in the third region A3 are arranged in a triangular grid pattern by arranging each nanoantenna 22 along the array line AL3. The array line AL3 is at an angle to the aforementioned reference line RL. .

[0049] In other words, the array pattern of the nanoantennas 22 in the third region A3 is obtained by rotating the array pattern of the nanoantennas 22 in the first region A1 about an axis perpendicular to the upper surface of the phosphor portion 21. The resulting pattern. In the lighting device 100, the angle... Other than integer multiples of 60° and different from angles The angle, for example, is 41°.

[0050] like Figure 2 As shown, each of the nanoantennas 22 is formed with a period P equal to the period of the other nanoantennas. The period P of the nanoantenna 22 is preferably less than the period of the peak wavelength of the fluorescence emitted from the phosphor in the phosphor portion 21 described above. For example, it is preferably 420 nm to 520 nm.

[0051] Furthermore, the diameter W of each of the nanoantennas 22 is equal to the diameter of the other nanoantennas. For example, the diameter W of the nanoantenna 22 is preferably 75% to 85% of the aforementioned period P. Specifically, for example, when the period P is 500 nm, the diameter W of the nanoantenna 22 is 375 nm to 425 nm.

[0052] Furthermore, the height H of each of the nanoantennas 22 from the upper surface of the phosphor portion 21 is equal to the height of the other nanoantennas. For example, the height H of the nanoantennas 22 is preferably 225 nm to 325 nm.

[0053] Each of the nanoantennas 22 is made of a dielectric or metallic material. More specifically, regarding the dielectric, the nanoantennas 22 are made of a material that is difficult to absorb light in the visible light range and has a high refractive index. For example, the nanoantennas 22 are made of a transparent dielectric material (such as titanium dioxide). Zirconia ( ), Niobium pentoxide ( ), Lanthanum oxide ( ), Tantalum pentoxide ( ) and hafnium oxide ( ))constitute.

[0054] The greater the refractive index difference between the nanoantenna 22 and air, the higher the scattering efficiency. Therefore, the nanoantenna 22 preferably has a high refractive index, particularly preferably 1.9 or higher. More specifically, regarding the metallic material, the nanoantenna 22 is composed of a material having a plasma frequency for surface plasmon resonance and an alloy or laminate containing these materials. For example, the nanoantenna 22 is made of a metallic material such as gold (Au), silver (Ag), copper (Cu), platinum (Pt), palladium (Pd), aluminum (Al), nickel (Ni), etc. (which serve as a material having a plasma frequency for surface plasmon resonance of the nanoantenna 22).

[0055] The period P, diameter W, height H, and constituent materials of the aforementioned nanoantenna 22 are common to the nanoantenna 22 in each of the first region A1, the second region A2, and the third region A3.

[0056] Here, the light narrowing effect of the nanoantenna 22 is described. When fluorescence reaches the upper surface of the phosphor portion 21 at an angle equal to or greater than the critical angle, the fluorescence undergoes total internal reflection on the upper surface of the phosphor portion 21. When total internal reflection occurs, an evanescent wave is generated that penetrates from the upper surface of the phosphor portion 21 toward the low refractive index medium side. The evanescent wave propagates along the upper surface of the phosphor portion 21, in other words, along the interface between the phosphor portion 21 and the air.

[0057] When the evanescent wave propagating along the upper surface of the phosphor portion 21 reaches the nanoantenna 22, it is emitted as visible light with the same wavelength as the fluorescence in a direction satisfying the diffraction conditions determined by the period P described above. This phenomenon results in fluorescence generation within the angular range satisfying the diffraction conditions and promotes the narrowing of the fluorescence emitted from the upper surface of the phosphor portion 21. The narrowing of the fluorescence of the nanoantenna 22 indicates, for example, that the fluorescence emitted at a light distribution angle within ±30° increases due to the effect of the nanoantenna 22.

[0058] Figure 1 and Figure 2 The arrangement of the nanoantennas 22 in each region shown is merely a schematic diagram illustrating the nanoantennas 22. The phosphor portion 21 is, for example, a 1 mm square; in this case, it is more... Figure 1 and Figure 2 The nanoantenna shown is equipped with more nanoantennas 22.

[0059] [Suppression of color unevenness in light emitted from lighting devices]

[0060] Here, using Figures 3 to 5 The description addresses the suppression of color inhomogeneity in the light emitted from the lighting device 100 in the embodiment.

[0061] Figure 3This diagram schematically illustrates a state in which a screen S is illuminated by light emitted from the lighting device 100 according to the embodiment. The screen S is located away from the lighting device 100. Figure 3 In this process, a circular illumination pattern IP is formed on the screen S by illuminating the screen S with light emitted from the illumination device 100. The illumination pattern IP is a white light pattern that is a mixture of blue light and yellow fluorescence.

[0062] Additionally, on screen S, bright line patterns BP1 (dashed line in the figure), BP2 (dotted line in the figure), and BP3 (dotted line in the figure) appear respectively, overlapping with the illumination pattern IP. In each of the bright line patterns BP1, BP2, and BP3, the bright line radiates outward from the center of the illumination pattern IP at 60° intervals.

[0063] Here, for reference Figure 4 describe Figure 3 The bright line patterns are illustrated in the figure. Bright line patterns BP1, BP2 and BP3 are fluorescence components in a specific wavelength range enhanced by nanoantenna 22, which appear due to the arrangement of nanoantenna 22 in the first region A1, the second region A2 and the third region A3, respectively.

[0064] Figure 4 This shows that the diffraction order is expressed as ( , ( and Under diffraction conditions (where the diffraction angle is an integer), the emission angle of the fluorescence emitted from the upper surface of the phosphor portion 21 is plotted for each emission angle. A graph showing the calculated wavelengths. Figure 4 In the middle, by Nanoantenna 22, made of refractive index 2.4, is formed at a period P of 420 nm on the upper surface of a phosphor portion 21 made of YAG:Ce phosphor, used as a model. The emission angle of fluorescence emitted along a direction perpendicular to the upper surface of the phosphor portion 21 is shown. It was set to 0°.

[0065] Figure 4 The shaded area in the figure represents the region where fluorescence generated in phosphor portion 21 and reaching the upper surface of phosphor portion 21 is enhanced by nanoantenna 22. Specifically, the region HA indicated by the double-dot chain line in the figure is the region where fluorescence is significantly enhanced by nanoantenna 22.

[0066] Specifically, among the fluorescence that has reached the upper surface of the phosphor portion 21, when emitted at an angle of 20° to 40°... During emission, the fluorescence component with wavelengths from 480 nm to 550 nm is significantly enhanced. The wavelength range of 480 nm to 550 nm corresponds to the green wavelength range of visible light. That is, in the illumination device 100, when the green fluorescence component is emitted from the upper surface of the phosphor portion 21 at the aforementioned angle, this green fluorescence component is significantly enhanced by the nanoantenna 22.

[0067] Figure 5 This is a graph illustrating visual sensitivity, showing the intensity of light within the visible light wavelength range perceived by the human eye. For example... Figure 5 As shown, visual sensitivity in the visible light wavelength range exhibits a higher trend in the green to orange wavelength range, with a peak near 550 nm in yellow light.

[0068] Refer again Figure 3 As described above, among the fluorescence generated in the phosphor portion 21, the emission angle is between 20° and 40°. The green fluorescent component emitted from the upper surface of the phosphor portion 21 is significantly enhanced by the nanoantenna 22.

[0069] Therefore, the corresponding green fluorescent components enhanced by the nanoantennas 22 in the first region A1, the second region A2, and the third region A3 are presented on the screen S as bright line patterns along the arrangement direction of the nanoantennas 22 arranged in a triangular grid in the corresponding regions, namely, bright line patterns BP1, BP2, and BP3, respectively. In each of the bright line patterns BP1, BP2, and BP3, the bright line radiates out at 60° intervals.

[0070] As described above, the array patterns of the nanoantennas 22 in the second region A2 and the third region A3 are obtained by rotating the array pattern of the nanoantennas 22 in the first region A1 by different angles around an axis perpendicular to the upper surface of the phosphor portion 21. Using the illumination device 100 of this embodiment, since the nanoantennas 22 have this arrangement, color inhomogeneity in the light emitted from the illumination device 100 can be suppressed.

[0071] Here, for example, in the lighting device 100, if the nanoantennas 22 are arranged in the same manner as in the first region A1, in other words, if the array patterns in the second region A2 and the third region A3 are not rotated, then only one bright line pattern will appear on the screen S. In other words, bright line patterns BP1, BP2, and BP3 will appear on the screen S with complete overlap and no displacement.

[0072] If the bright line pattern overlaps in this way on screen S, then it is similar to... Figure 5Along with the high visual sensitivity within the visible light range, the color difference between the parts of the bright line pattern that appear and those that do not will be amplified when viewed by the human eye. Specifically, although the illuminated pattern IP will be white, the overlapping bright line patterns will appear as a strong green. Therefore, a noticeable color inconsistency may appear in the light illuminating the screen S from the illumination device 100.

[0073] According to the lighting device 100 of this embodiment, the array patterns in the second region A2 and the third region A3 are respectively obtained by rotating the array pattern in the first region A1 by an angle. and The resulting pattern. Therefore, the corresponding arrangement directions of the nanoantennas 22 in the first region A1, the second region A2, and the third region A3 are different from each other in the plan view of the illumination device 100 viewed from above.

[0074] Therefore, the bright line pattern BP2 appearing on screen S is rotated by the same angle as the bright line pattern BP1, which deviates from the array pattern in the second region A2. Similarly, the bright line pattern BP3 appearing on screen S is rotated at an angle relative to the bright line pattern BP1, deviating from the array pattern in the third region A3. In other words, in this way, the bright line patterns BP1, BP2, and BP3 do not overlap on the screen S, as shown below. Figure 3 As shown.

[0075] Therefore, in the illumination device 100 according to the embodiment, by changing the arrangement of the nanoantennas 22 in each region, the bright line patterns do not overlap. Therefore, compared to the case where the nanoantennas 22 have a uniform arrangement, color unevenness may be less noticeable.

[0076] In other words, because the alignment of the nanoantennas 22 varies by region, the bright lines are finely dispersed on the screen S. As a result, color inhomogeneity is less likely to occur in the light illuminating the screen S. Therefore, by using the illumination device 100 of this embodiment, color inhomogeneity in the light emitted from the illumination device 100 via the nanoantennas 22 can be suppressed.

[0077] The light emitted from the lighting device 100 of this embodiment has a luminous flux similar to that emitted from the lighting device when all nanoantennas 22 are arranged in a uniform configuration, as described above. For example, the luminous flux of the light emitted from the lighting device when all nanoantennas 22 are arranged in a uniform configuration is 231 lm / W, while the luminous flux of the light emitted from the lighting device 100 of this embodiment is 232 lm / W.

[0078] Therefore, by using the lighting device 100 of this embodiment, color inhomogeneity in the light emitted from the lighting device 100 can be suppressed while maintaining the luminous flux of the light.

[0079] In the lighting device 100 of this embodiment, Figure 1 The three regions shown (region A1, region A2, and region A3) are merely an example. The number of regions and the number of nanoantennas 22 formed in each region are not limited, as long as color inhomogeneity in the emitted light can be suppressed. For example, only two regions (region A1 and region A2) could be provided.

[0080] In another aspect, for example, the arrangement of the first region A1, the second region A2, and the third region A3 is defined as a group, and multiple groups can be formed on the upper surface of the phosphor portion 21. In this case, it is preferable to divide the corresponding regions occupying the entire area as evenly as possible.

[0081] The size of each unit region is preferably one that allows for the formation of at least 10 cycles of the nanoantenna 22. For example, the unit region preferably has one side with a diameter of 5 μm or larger along each grid axis.

[0082] In the lighting device 100 of this embodiment, the angle is the rotation angle of the array pattern in the second region A2. It is 19°, and is the angle of rotation of the array pattern in the third region A3. The angle is 41°. However, this should not be interpreted in a limiting sense. When the nanoantenna 22 has a triangular grid-like array pattern, only angles exceeding multiples of 60° are required. For example, the angle... It can be 5°, and the angle It can be 50°.

[0083] Note that the rotation angle difference between adjacent regions is preferably set in increments of 20°, more preferably in increments of 10°, and even more preferably in increments of 5° or less. By arranging the regions such that the angle difference between adjacent regions is minimized, as many nanoantennas 22 as possible can be formed in each of the adjacent regions.

[0084] In the lighting device 100 of this embodiment, the nanoantenna 22 has a triangular grid-like array pattern in each of the first region A1, the second region A2, and the third region A3, but this should not be interpreted in a limiting sense. For example, the nanoantenna 22 may have a square grid-like array pattern.

[0085] When the nanoantenna 22 has a square grid-like array pattern in each region, color unevenness may occur because the bright lines appear radially at 90° on the illumination pattern IP of the emitted light from the illumination device 100 and are projected onto the screen S. Therefore, in this case, the color unevenness can be achieved by adjusting the aforementioned angles. and angle Setting angles that are different from each other and are not multiples of 90° suppresses color inhomogeneity in the emitted light.

[0086] In the lighting device 100 of this embodiment, the nanoantenna 22 has a cylindrical shape. However, the nanoantenna 22 is not limited to this and may have another shape. For example, the nanoantenna 22 may have a conical shape or a truncated conical shape. In this case, the diameter of the bottom surface of the nanoantenna having a conical shape or a truncated conical shape corresponds to the diameter W of the nanoantenna 22 described above.

[0087] In the lighting device 100 of this embodiment, the wavelength conversion device 13 generates fluorescence upon receiving excitation light from the light-emitting element 12, which serves as a light source; however, the light source is not limited to this. For example, a laser source that emits laser light can be used. In this case, the wavelength conversion device 13 and the light source can be configured separately in the lighting device 100.

[0088] [Manufacturing method of wavelength conversion device]

[0089] use Figure 1 and Figure 2 The following describes a method for manufacturing the wavelength conversion device 13 of the lighting device 100 according to an embodiment.

[0090] First, a transparent dielectric material is formed on the upper surface of the planar phosphor portion 21 by electron beam evaporation or sputtering deposition. The dielectric layer is fabricated. At this point, the thickness of the dielectric layer is equal to the height H of the nanoantenna 22.

[0091] Next, a metal film made of aluminum (Al) is formed on the dielectric layer formed on the upper surface of the phosphor portion 21, and a resist film made of resin is applied to the metal film. Then, using a mold for nanoimprint lithography with multiple holes, the desired patterning of the resist film is performed by pressure bonding the mold to the resist film and then peeling off the mold.

[0092] In patterning, by matching the period and diameter of each of the plurality of holes in the mold used for nanoimprint lithography with the period P and diameter W of the nanoantenna 22 described above, a resist film having a shape corresponding to the arrangement of the nanoantenna 22 in the embodiment can be formed.

[0093] At this time, by performing patterning while rotating the mold for nanoimprint lithography at a predetermined angle for each of the first region A1, the second region A2 and the third region A3, a resist film having a shape corresponding to the arrangement of the nanoantennas 22 in each of the first region A1, the second region A2 and the third region A3 can be formed.

[0094] Next, a patterned resist film is used as a mask to form a metal mask for etching the dielectric layer by etching a metal film in the area where the nanoantenna 22 is not formed by dry etching.

[0095] Subsequently, the dielectric layer with the metal mask is etched using dry etching. For example, when the metal film is made of Al and the transparent dielectric is made of... During fabrication, etching gases of chlorine (Cl) and argon (Ar) are used for the metal film, and carbon tetrafluoride ( Ar, oxygen ( Etching gases such as those used in transparent dielectrics are employed.

[0096] Finally, by removing the metal mask remaining in the above process through dry etching or wet etching, a wavelength conversion device 13 with nanoantenna 22 arranged as described above can be manufactured.

[0097] When the metal film is made of Al and the transparent dielectric is made of... When making, use Ar The etching gas performs dry etching on the dielectric layer, causing the metal film to be partially etched. Therefore, when a thin metal film is pre-formed on the dielectric layer, the metal film and dielectric layer are removed from the ends of the dielectric layer during etching. As a result, using this method, nanoantennas with conical or truncated conical shapes can be formed.

[0098] [Example of a modification to a lighting fixture]

[0099] use Figure 6 The following describes a modification of the lighting device 100 according to Embodiment 1. Figure 6 This is a top view of the lighting device 110 according to a modified embodiment 1. In the lighting device 110, the nanoantenna 22 has an arrangement different from that in embodiment 1. Other aspects (such as the period P, diameter W, and height H of the nanoantenna 22) are similar to those in embodiment 1.

[0100] In this modified illumination device 110, the nanoantennas 22 are formed in a triangular grid array pattern in each of the nine regions arranged in a matrix, from the fourth region A4 to the twelfth region A12. The array patterns of the nanoantennas 22 in each of the fifth region A5 to the twelfth region A12 rotate at different angles relative to the array pattern in the fourth region A4 about an axis perpendicular to the upper surface of the phosphor portion 21.

[0101] The nanoantenna 22 in the fourth region A4 has a similar arrangement to the nanoantenna 22 in the first region A1, and is arranged along the array line AL4, thus having a triangular grid array pattern.

[0102] Furthermore, the nanoantennas 22 in each of the fifth region A5 to the twelfth region A12 are arranged along array lines AL5 to AL12, respectively, thus forming a triangular grid-like array pattern. Each of the array lines AL5 to AL12 has a reference line parallel to array line AL4 ( Figure 6 (Not shown in the example) Angles that are multiples of 7°. The angles vary in each region and are not multiples of 60°.

[0103] In other words, the array pattern of the nanoantenna 22 in each of the fifth region A5 to the twelfth region A12 is obtained by rotating the array pattern of the nanoantenna 22 in the fourth region A4 by a multiple of 7° around the axis perpendicular to the upper surface of the phosphor portion 21.

[0104] Specifically, for example, the array pattern of the nanoantennas 22 in the fifth region A5 is obtained by rotating the array pattern of the nanoantennas 22 in the fourth region A4 by 7° around an axis perpendicular to the upper surface of the phosphor portion 21. The array pattern of the nanoantennas 22 in the sixth region A6 is obtained by rotating the array pattern of the nanoantennas 22 in the fourth region A4 by 14° around an axis perpendicular to the upper surface of the phosphor portion 21.

[0105] In other words, in a plan view of the lighting device 110 viewed from above, the array patterns of nanoantennas 22 in adjacent regions of the fifth region A5 to the twelfth region A12 have a rotation angle of 7° relative to each other.

[0106] By rotating the array pattern of the nanoantenna 22 in each of the regions set in a matrix, such as in the modified illumination device 110, color inhomogeneity in the light emitted from the illumination device 110 via the nanoantenna 22 can also be suppressed.

[0107] In the illumination device 110 of this modified example, the array patterns of the nanoantennas 22 in the fifth region A5 to the twelfth region A12 are rotated by different angles from each other. However, the angles do not need to be different in all regions. In one aspect, multiple regions can have the same angle. For example, in one aspect, three regions can have array patterns rotated by 7°, another three regions can have array patterns rotated by 28°, and yet another three regions can have array patterns rotated by 49°.

[0108] Implementation Method 2

[0109] [Lighting device according to embodiment 2]

[0110] Next, use Figures 7 to 9 The structure of the lighting device 200 according to embodiment 2 is described. Figure 7 Is along with Figure 1 The image shows a cross-sectional view of the lighting device 200 taken at the same position as line 2-2 in the diagram. The lighting device 200 differs from Embodiment 1 in that the wavelength conversion device 13 has a multilayer reflector 23. Other aspects (such as the arrangement of the nanoantennas 22 in the first region A1 to the third region A3) are similar to Embodiment 1.

[0111] The multilayer mirror 23 is a mirror formed on the upper surface of the phosphor portion 21 and constructed by laminating multiple layers of dielectric materials with relatively low refractive indices and dielectric materials with high refractive indices. The multilayer mirror 23 has an upper surface on which a corresponding nanoantenna 22 is formed as shown in Embodiment 1.

[0112] In the multilayer mirror 23, for example, silicon dioxide is used ( )or As a dielectric material with a low refractive index, and used , , , , or As a dielectric material with a high refractive index.

[0113] In the lighting device 200, the multilayer film reflector 23 reflects light within the green wavelength range of the visible light range with a predetermined reflectivity and transmits light with other wavelengths. That is, the multilayer film reflector 23 only reflects the fluorescence component within the green wavelength range of the fluorescence generated in the phosphor portion 21, and transmits blue light, which is the excitation light that has passed through the phosphor portion 21, and fluorescence components outside the green wavelength range.

[0114] Figure 8This is a graph illustrating an exemplary reflectivity of light with visible wavelengths in a multilayer reflector 23. For example... Figure 8 As shown, the multilayer reflector 23 has a reflectivity of 60% or less for light in the green wavelength range of approximately 480 nm to 530 nm.

[0115] Therefore, in the lighting device 200 of this embodiment, the multilayer film reflector 23 is formed on the upper surface of the phosphor portion 21. Thus, when fluorescence in the green wavelength range (which may be due to the color inhomogeneity described above) reaches the multilayer film reflector 23, some of the fluorescence can be reflected into the phosphor portion 21.

[0116] Figure 9 This is a graph illustrating the excitation spectrum of the phosphor in phosphor section 21. Figure 9 In the diagram, the horizontal axis represents wavelength, and the vertical axis represents intensity. Figure 9 In the diagram, the area indicated by the dotted line represents the region showing light within the green wavelength range. For example... Figure 9 As shown, light in the green wavelength range can excite the phosphor in phosphor portion 21, but the intensity is reduced compared to blue light.

[0117] Therefore, in the lighting device 200 of this embodiment, by forming a multilayer film reflector 23 on the upper surface of the phosphor portion 21 that reflects the fluorescence component in the green wavelength range, the phosphor component reflected by the multilayer film reflector 23 can be used again as excitation light to excite the phosphor of the phosphor portion 21.

[0118] Therefore, by utilizing the illumination device 200 of this embodiment, in addition to suppressing the effect of color inhomogeneity in the emitted light by rotating the array pattern of the nanoantennas 22 in each region, color inhomogeneity in the emitted light can also be suppressed by using the multilayer film reflector 23 to prevent a portion of the fluorescence component in the green wavelength range from being emitted from the phosphor portion 21. Thus, by utilizing the illumination device 200 of this embodiment, color inhomogeneity in the light emitted from the illumination device 200 via the nanoantennas 22 can be suppressed.

[0119] The reflectivity of the multilayer reflector 23 for light in the green wavelength range is not limited to the reflectivity described above, and can be appropriately set. For example, the reflectivity can be set according to the number of regions per array pattern of the nanoantenna 22, or the reflectivity can be appropriately adjusted to a degree that does not reduce the luminous flux of the light emitted from the illumination device 200.

[0120] Description of reference numerals in the attached figures

[0121] 100, 110, 200 lighting fixtures

[0122] 11 Mounting Plate

[0123] 12 Light-emitting elements

[0124] 13 Wavelength conversion device

[0125] 15 Semiconductor structural layers

[0126] 16 Supporting substrate

[0127] 17 p electrode

[0128] 18 n electrode

[0129] 21. Phosphorite section

[0130] 22 nanometer antenna

[0131] 23 Dielectric Multilayer Film

Claims

1. A wavelength conversion device, the wavelength conversion device comprising: A plate-shaped phosphor portion, wherein the phosphor portion contains a phosphor that generates fluorescence when excited by excitation light; as well as Multiple nanoantennas, in a planar view viewed from a direction perpendicular to a plane of the phosphor portion, are arranged in a grid-like array pattern in each of multiple regions of the plane. The multiple nanoantennas are made of a metallic or dielectric material. The array pattern of the plurality of nanoantennas in one of the plurality of regions is obtained by rotating the array pattern of the plurality of nanoantennas in another region about an axis perpendicular to the surface.

2. The wavelength conversion device according to claim 1, wherein, The plurality of nanoantennas are configured to form a triangular grid-like array pattern in each of the plurality of regions, and The array pattern of the plurality of nanoantennas in one region is obtained by rotating the array pattern of the plurality of nanoantennas in other regions by an angle other than a multiple of 60°.

3. The wavelength conversion device according to claim 1, wherein, The plurality of nanoantennas are configured to form a square grid-like array pattern in each of the plurality of regions, and The array pattern of the plurality of nanoantennas in one region is obtained by rotating the array pattern of the plurality of nanoantennas in other regions by an angle other than a multiple of 90°.

4. The wavelength conversion device according to claim 1, wherein, The plurality of regions are strip-shaped regions, and each of the strip-shaped regions is arranged along one direction in the plan view.

5. The wavelength conversion device according to claim 1, wherein, The multiple regions are arranged in a matrix on the plan view.

6. The wavelength conversion device according to claim 1, wherein the wavelength conversion device comprises: A dielectric multilayer film is formed on one surface of the phosphor portion, the dielectric multilayer film being configured to reflect fluorescence components within a portion of the wavelength range of the fluorescence.

7. The wavelength conversion device according to claim 6, wherein, The fluorescence wavelength range is from 480 nm to 700 nm, and The dielectric multilayer film is configured to reflect fluorescence components in the wavelength range from 480 nm to 530 nm.

8. The wavelength conversion device according to claim 7, wherein, The dielectric multilayer film has a reflectivity of 60% or less for the fluorescence component.

9. The wavelength conversion device according to claim 1, wherein, The plurality of nanoantennas are arranged in each of the plurality of regions with a period of 420 nm or greater and 520 nm or less.

10. The wavelength conversion device according to claim 9, wherein, The plurality of nanoantennas have a cylindrical, conical, or truncated conical shape in each of the plurality of regions, and have a bottom surface with a diameter of 75% or greater and 85% or less of the period.

11. The wavelength conversion device according to claim 9 or 10, wherein, The plurality of nanoantennas have a height of 225 nm or greater and 325 nm or less in each of the plurality of regions.

12. A lighting device, the lighting device comprising: The wavelength conversion device according to claim 1; as well as A light source that emits excitation light toward a side opposite to one of the faces of the phosphor portion.

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