Illumination device and wavelength conversion element

Abstract

To solve the following problem that: a wavelength conversion element generates heat when light is converted into converted light; cooling a part of the wavelength conversion element with a cooling element causes a temperature difference within the wavelength conversion element; and such a temperature difference may cause the wavelength conversion element to deform or break.SOLUTION: An illumination device comprises: multiple individual light sources aligned in an arrangement direction and configured to emit light; a wavelength conversion element provided with an incidence surface opposed to the plurality of individual light sources and receiving the light, and an emission surface intersecting the incidence surface, the wavelength conversion element converting the wavelength of the light; and a cooling member cooling a surface of the wavelength conversion element that differs from the incidence surface. The wavelength conversion element is formed of a first element member and a second element member arranged in the arrangement direction of the first element member and coupled thereto.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present disclosure relates to a lighting device and a wavelength conversion element. [Background technology]

[0002] An illumination device having multiple solid-state light sources is known. The illumination device described in Patent Document 1 has multiple solid-state light sources and a ceramic body that is a wavelength conversion element. The multiple solid-state light sources are arranged along a radiation input surface of the ceramic body. The multiple solid-state light sources supply light to the radiation input surface. Light is supplied to the ceramic body. The ceramic body converts the light into converted light. The ceramic body is configured in a rectangular parallelepiped or rod shape with a predetermined aspect ratio. The illumination device includes a cooling element, such as a heat sink, that cools the ceramic body. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Special Publication No. 2018-529201 Summary of the Invention [Problem to be solved by the invention]

[0004] A wavelength conversion element generates heat when converting light into converted light. When part of a wavelength conversion element is cooled by a cooling element, a temperature difference occurs within the wavelength conversion element. This temperature difference may cause deformation or damage to the wavelength conversion element. [Means for solving the problem]

[0005] The lighting device of the present disclosure includes a plurality of solid-state light sources arranged in an arrangement direction and emitting light, a wavelength conversion element having an incident surface facing the plurality of solid-state light sources and through which the light is incident, and an exit surface intersecting the incident surface, and converting the wavelength of the light, and a cooling member for cooling a surface of the wavelength conversion element other than the incident surface, wherein the wavelength conversion element is composed of a first element member and a second element member arranged in the arrangement direction of the first element member and connected to the first element member.

[0006] The wavelength conversion element of the present disclosure is a wavelength conversion element that is arranged opposite a plurality of solid-state light sources that are arranged in an arrangement direction and emit light, and a cooling member, and has a first element member and a second element member that is arranged in the arrangement direction of the first element member and connected to the first element member. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 1 is a diagram showing a schematic configuration of a lighting device. [Figure 2] FIG. 2 is a diagram showing a schematic configuration of a light collector. [Figure 3] FIG. 2 is a diagram showing a schematic configuration of a light collector. [Figure 4] FIG. 2 is a diagram showing a cross-sectional configuration of a phosphor and a light-emitting unit. [Figure 5] FIG. 2 is a diagram showing a cross-sectional configuration of a phosphor and a light-emitting unit. [Figure 6A] FIG. 4 is a diagram showing the surface structure of a first light exit surface of a first fluorescent member. [Figure 6B] FIG. 4 is a diagram showing the surface structure of a first light exit surface of a first fluorescent member. [Figure 7A] FIG. 4 is a diagram showing the surface structure of a first light exit surface of a first fluorescent member. [Figure 7B] FIG. 4 is a diagram showing the surface structure of a first light exit surface of a first fluorescent member. [Figure 8A] FIG. 4 is a diagram showing the surface structure of a first light exit surface of a first fluorescent member. [Figure 8B] FIG. 4 is a diagram showing the surface structure of a first light exit surface of a first fluorescent member. [Figure 9] FIG. 10 shows the evaluation results of each microstructure. [Figure 10]FIG. 2 is a diagram showing a cross-sectional configuration of a phosphor and a light-emitting unit. DETAILED DESCRIPTION OF THE INVENTION

[0008] FIG. 1 shows a schematic configuration of an illumination device 1. The illumination device 1 emits light of a predetermined wavelength along an optical axis AX. The illumination device 1 is used as a light source for a projector or the like. The illumination device 1 includes a light collector 10, a light-emitting unit 20, a support 30, and a cooling element body 50. The illumination device 1 corresponds to an example of an illumination apparatus.

[0009] Several figures, including FIG. 1, illustrate an XYZ coordinate system. The Z axis is an axis parallel to the optical axis AX of the lighting device 1. The +Z direction is the direction in which the lighting device 1 emits light. The -Z direction is the opposite direction to the direction in which the lighting device 1 emits light. The Y axis is an axis perpendicular to the Z axis. The +Y direction is the direction upward from the top surface of the support 30 shown in FIG. 1. The -Y direction is the direction downward from the top surface of the support 30 shown in FIG. 1. The X axis is an axis perpendicular to the Z axis and the Y axis. The +X direction is the direction from the first side surface S5 to the second side surface S6 of the phosphor 11, which will be described later. The -X direction is the direction from the second side surface S6 to the first side surface S5 of the phosphor 11.

[0010] The light collector 10 emits light of a predetermined wavelength in the +Z direction. The light collector 10 collects the light emitted from the light-emitting unit 20. The light collector 10 converts the emitted light into converted light of a predetermined wavelength. The light collector 10 emits the converted light as light of the predetermined wavelength along the optical axis AX.

[0011] The light-emitting unit 20 emits light toward the light collector 10. The light-emitting unit 20 is composed of a plurality of light-emitting elements 21. The light-emitting unit 20 shown in FIG. 1 is disposed in a position in the +Y direction of the light collector 10. The light-emitting unit 20 may be disposed in a position in the +X direction or a position in the -Y direction of the light collector 10. The light-emitting unit 20 may be disposed in two or more positions selected from the positions in the +Y direction, the +X direction, and the -Y direction of the light collector 10. The positions and number of the light-emitting units 20 can be set as appropriate.

[0012] The support 30 supports the light collector 10. The support 30 is in contact with the light collector 10 and supports the light collector 10. The support 30 shown in FIG. 1 is in contact with a lower surface S2, which is the surface of the light collector 10 in the -Y direction, at a position in the -Y direction of the light collector 10, and supports the light collector 10. The support 30 cools the lower surface S2 by coming into contact with the lower surface S2. The support 30 corresponds to an example of a cooling member. The support 30 shown in FIG. 1 is provided on the side and lower surface of the light collector 10, but is not limited to this. The configuration of the support 30 is set as appropriate.

[0013] The cooling element 50 cools the light collector 10. The cooling element 50 may also cool the light-emitting unit 20. The cooling element 50 is disposed on the support 30. The cooling element 50 is in contact with the support 30 and cools the support 30. The cooling element 50 cools the support 30, thereby cooling the light collector 10 in contact with the support 30. The cooling element 50 cools the light collector 10 via the support 30.

[0014] Fig. 2 shows a schematic configuration of the collector 10. Fig. 2 shows a perspective view of the collector 10. Fig. 2 shows the collector 10, the light-emitting unit 20, and a collector support portion 30a that is a part of the support body 30. The collector 10 includes a phosphor 11 and an optical element 15.

[0015] The light-emitting unit 20 is disposed at a position in the +Y direction of the phosphor 11. The light-emitting unit 20 is disposed at a position facing the upper surface S1, which is the surface in the +Y direction of the phosphor 11. The light-emitting unit 20 has a plurality of light-emitting elements 21.

[0016] The light-emitting element 21 emits light having a predetermined wavelength to the phosphor 11. The light-emitting element 21 is configured with an LED (Light-Emitting Diode) or an OLED (Organic Light-Emitting Diode). The light-emitting element 21 corresponds to an example of a solid-state light source. The plurality of light-emitting elements 21 are arranged at a position facing the upper surface S1 of the phosphor 11. The plurality of light-emitting elements 21 are arranged along an arrangement direction parallel to the Z axis. The arrangement direction is a direction parallel to the optical axis AX. The plurality of light-emitting elements 21 emit light to the upper surface S1 of the phosphor 11. The number of light-emitting elements 21 is, for example, 2 to 15, but is not limited to this. The number of light-emitting elements 21 is set appropriately depending on the amount of light emitted from the light collector 10.

[0017] The phosphor 11 absorbs the light emitted from the plurality of light-emitting elements 21 and emits fluorescence. The light emitted from the plurality of light-emitting elements 21 enters the phosphor 11 from the upper surface S1 of the phosphor 11. The phosphor 11 absorbs the light emitted from the plurality of light-emitting elements 21 as excitation light and emits fluorescence. The fluorescence is totally reflected at the interface between the phosphor 11 and air and propagates within the phosphor 11. The propagated fluorescence is emitted from the light-emitting end surface S4 of the phosphor 11. The light-emitting end surface S4 will be described later. The phosphor 11 emits the fluorescence from the light-emitting end surface S4 toward the optical element 15. The phosphor 11 converts the wavelength of the excitation light by emitting fluorescence from the excitation light. For example, the phosphor 11 converts the excitation light, which is blue light, into yellow fluorescence. The wavelength of the blue light is 400 to 480 nm. The wavelength of the yellow light is 490 to 750 nm. The phosphor 11 corresponds to an example of a wavelength conversion element.

[0018] As an example, the phosphor 11 is a rectangular parallelepiped having an upper surface S1, a lower surface S2, a reflecting end surface S3, a light-emitting end surface S4, a first side surface S5, and a second side surface S6. The lower surface S2, the reflecting end surface S3, the first side surface S5, and the second side surface S6 will be described later. The phosphor 11 is not limited to a rectangular parallelepiped. The phosphor 11 may have a polygonal prism shape such as a triangular prism, or may have a cylindrical shape. It is preferable that the phosphor 11 be a rectangular parallelepiped.

[0019] The phosphor 11 is configured in a shape in which the length along the Z axis is greater than the width along the X axis. The aspect ratio, which is the ratio of the length along the Z axis to the width along the X axis, is greater than 1. The aspect ratio is preferably 10 or greater and 100 or less. The larger the aspect ratio, the greater the length along the Z axis. A longer length along the Z axis makes it possible to increase the number of light-emitting elements 21 arranged on the upper surface S1. The greater the number of light-emitting elements 21 arranged on the upper surface S1, the greater the amount of light emitted by the light collector 10.

[0020] The phosphor 11 is made using Y2O3 powder, Al2O3 powder, and CeO2 powder. A raw material powder containing Y2O3 powder, Al2O3 powder, and CeO2 powder is mixed with ethanol. The raw material powder is mixed with ethanol while being pulverized in a ball mill and stirred. A slurry containing the raw material powder and ethanol is produced by stirring. When the slurry is produced, a sintering aid containing Si element may be added to the slurry. Examples of the sintering aid include SiO2, CaO, MgO, etc. The sintering aid is added in an amount that leaves about 500 ppm of the raw material powder after sintering. The sintering aid may be TEOS (tetraethyl orthosilicate). When the sintering aid is TEOS, the amount of TEOS added is an amount that leaves about 500 ppm of equivalent substances such as SiO2, CaO, MgO, etc. after sintering.

[0021] After the slurry is produced, the raw material powder in the slurry is dried after the ethanol is removed. The dried raw material powder is sieved. The sieve removes coarse particles from the raw material powder. The raw material powder is granulated into secondary particles with particle sizes ranging from several μm to several hundred μm. The primary particle sizes of Y2O3, Al2O3, and CeO2 contained in the secondary particles are several tens to several hundred nm.

[0022] The raw material powder granulated into secondary particles is formed into a green body using a mold of the desired shape. The green body is processed using cold isostatic pressing at a pressure of several hundred MPa. The green body is debound at 600°C or higher. The debound green body is vacuum-fired at 1700°C or higher to produce a transparent phosphor ceramic. The resulting transparent phosphor ceramic is then HIP-treated at 1700°C or higher. HIP stands for hot isostatic pressing. The vacuum firing and HIP treatments reduce the activity of Ce and cause oxygen deficiencies. After HIP treatment, the transparent phosphor ceramic is subjected to a two-stage annealing treatment. The activity of Ce is increased by adjusting the treatment time of the first annealing treatment. The activity of Ce is further improved and the quantum efficiency is adjusted by adjusting the treatment temperature of the second annealing treatment. The transparent phosphor ceramic that has undergone the two-stage annealing treatment is used as phosphor 11.

[0023] The optical element 15 receives the light emitted from the phosphor 11 and emits it to the outside. The optical element 15 is composed of an optical filter, a reflector, an optical lens, etc. The optical element 15 is appropriately selected depending on the application of the light collector 10. The optical element 15 may be disposed in contact with the phosphor 11, or may be disposed spaced apart from the phosphor 11. The optical element 15 shown in FIG. 2 is disposed in contact with the light-emitting end surface S4 of the phosphor 11.

[0024] The collector support 30a is a portion of the support body 30 that supports the phosphor 11. The collector support 30a comes into contact with the phosphor 11 at a position in the -Y direction of the phosphor 11 and supports the phosphor 11. The contact of the collector support 30a with the phosphor 11 causes the support body 30 to cool the phosphor 11. The collector support 30a shown in FIG. 2 is configured to surround the phosphor 11, but is not limited to this. The configuration of the collector support 30a is set as appropriate.

[0025] FIG. 3 shows a schematic configuration of the collector 10. FIG. 3 shows a plan view of the collector 10 from the -Z direction. The light-emitting unit 20 is omitted from FIG. 3. FIG. 3 shows a collector support 30a, which is a part of the support body 30. The collector support 30a shown in FIG. 3 schematically shows its relationship with the phosphor 11. FIG. 3 shows the upper surface S1, lower surface S2, reflective end surface S3, first side surface S5, and second side surface S6 of the phosphor 11.

[0026] The upper surface S1 is a surface of the phosphor 11 in the +Y direction. The upper surface S1 faces a plurality of light-emitting elements 21 (not shown). The upper surface S1 receives light emitted from the plurality of light-emitting elements 21. The upper surface S1 corresponds to an example of an incident surface.

[0027] The lower surface S2 is the surface of the phosphor 11 in the -Y direction. The lower surface S2 is in contact with the collector support 30a and is supported by the collector support 30a. Heat generated by the phosphor 11 absorbing fluorescence and excitation light at the lower surface S2 is absorbed by the collector support 30a. The support 30 cools the lower surface S2 of the phosphor 11 by absorbing the heat generated by the phosphor 11 from the lower surface S2. The lower surface S2 corresponds to an example of a surface different from the incident surface.

[0028] The reflecting end surface S3 is the surface of the phosphor 11 in the -Z direction. The reflecting end surface S3 intersects with the upper surface S1. The reflecting end surface S3 totally reflects the excitation light and fluorescence propagating within the phosphor 11. The reflecting end surface S3 prevents the fluorescence and the like from emitting from the reflecting end surface S3. The reflecting end surface S3 propagates the excitation light and fluorescence to the light-emitting end surface S4. A reflective material may be provided on the reflecting end surface S3.

[0029] The first side surface S5 is the surface of the phosphor 11 in the -X direction. The first side surface S5 shown in FIG. 3 is spaced apart from the collector support 30a. The first side surface S5 totally reflects the excitation light and fluorescence propagating within the phosphor 11. The first side surface S5 prevents the fluorescence and the like from emitting from the first side surface S5. The first side surface S5 propagates the excitation light and fluorescence to the light-emitting end surface S4.

[0030] The second side surface S6 is the surface of the phosphor 11 in the +X direction. The second side surface S6 shown in FIG. 3 is spaced apart from the collector support 30a. The second side surface S6 totally reflects the excitation light and fluorescence propagating within the phosphor 11. The second side surface S6 prevents the fluorescence and the like from emitting from the second side surface S6. The second side surface S6 propagates the excitation light and fluorescence to the light-emitting end surface S4.

[0031] 3, the phosphor 11 is in contact with the collector support 30a at the bottom surface S2, but is not limited to this. At least one of the first side surface S5 and the second side surface S6 of the phosphor 11 may be in contact with the collector support 30a. When the first side surface S5 is in contact with the collector support 30a, the first side surface S5 is cooled by the support 30. When the second side surface S6 is in contact with the collector support 30a, the second side surface S6 is cooled by the support 30.

[0032] 3 faces the plurality of light-emitting elements 21 and receives light emitted from the plurality of light-emitting elements 21, but is not limited to this configuration. At least one of the bottom surface S2, the first side surface S5, and the second side surface S6 may face the plurality of light-emitting elements 21 and receive light emitted from the plurality of light-emitting elements 21. In this case, the phosphor 11 is supported by the light collector support 30a on a surface other than the surface facing the plurality of light-emitting elements 21.

[0033] Fig. 4 shows a cross-sectional configuration of the phosphor 11 and the light-emitting unit 20. Fig. 4 schematically shows the cross-sectional configuration of the phosphor 11 and the light-emitting unit 20. Fig. 4 shows a YZ cross section of the phosphor 11 and the light-emitting unit 20. Fig. 4 shows a first phosphor 11a as the phosphor 11. The plurality of light-emitting elements 21 included in the light-emitting unit 20 are arranged in an arrangement direction parallel to the optical axis AX.

[0034] The first phosphor 11a is an example of the phosphor 11. The first phosphor 11a is composed of a first fluorescent member 111 and a second fluorescent member 112. The first phosphor 11a is composed by connecting the first fluorescent member 111 and the second fluorescent member 112.

[0035] The first fluorescent member 111 is made of transparent phosphor ceramic. The first fluorescent member 111 is a rectangular parallelepiped whose length along the Z axis is greater than its width along the X axis. The first fluorescent member 111 absorbs the light emitted from the plurality of light-emitting elements 21 as excitation light and emits fluorescence. The first fluorescent member 111 has a first incident surface S11, a first supporting surface S12, a first end surface S13, and a first exit surface S14. The first fluorescent member 111 corresponds to an example of a first element member.

[0036] The first incident surface S11 is a surface of the first fluorescent member 111 in the +Y direction. The first incident surface S11 faces the plurality of light-emitting elements 21 included in the light-emitting unit 20. The first incident surface S11 receives light emitted from the plurality of light-emitting elements 21. The first incident surface S11 forms a part of the upper surface S1 of the first phosphor 11a. The first incident surface S11 corresponds to an example of a first element incident surface.

[0037] The first support surface S12 is the surface of the first fluorescent member 111 facing the -Y direction. The first support surface S12 comes into contact with the collector support part 30a and is cooled by the support body 30. The first support surface S12 forms part of the lower surface S2 of the first fluorescent member 11a.

[0038] The first end surface S13 is the surface of the first fluorescent member 111 in the -Z direction. The first end surface S13 corresponds to the reflective end surface S3 of the first fluorescent body 11a. The first end surface S13 totally reflects the excitation light and fluorescence propagating within the first fluorescent member 111.

[0039] The first exit surface S14 is the surface of the first fluorescent member 111 in the +Z direction. The first exit surface S14 emits fluorescence toward the second fluorescent member 112. It is preferable that the first exit surface S14 is subjected to surface treatment such as microfabrication or roughening. The surface treatment makes it easier for fluorescence to be emitted from the first exit surface S14. The microfabrication will be described later.

[0040] As an example, the first exit surface S14 is subjected to a roughening treatment such as surface processing. When the first exit surface S14 is subjected to a roughening treatment, the roughness of the first exit surface is configured to be rougher than the roughness of the first entrance surface. The roughness of the first exit surface is the surface roughness of the first exit surface S14 and corresponds to an example of the surface roughness of the coupling surface. The roughness of the first entrance surface is the surface roughness of the first entrance surface S11 and corresponds to an example of the surface roughness of the entrance surface. The roughness of the first exit surface is configured to be rougher than the surface roughness of the first support surface S12 and the surface roughness of the first end surface S13. The roughness of the first exit surface is configured to be rougher than the surface roughness of both side surfaces of the first fluorescent member 111. By configuring the roughness of the first exit surface to be rougher than the surface roughness of the other surfaces, the amount of fluorescent light emitted from the first exit surface S14 is greater than when the roughness of the first exit surface is configured to be equal to the surface roughness of the other surfaces. The first light exit surface S14 faces the second fluorescent member 112. The first light exit surface S14 corresponds to an example of a first coupling surface.

[0041] The second fluorescent member 112 is made of transparent phosphor ceramic. The second fluorescent member 112 is a rectangular parallelepiped whose length along the Z axis is greater than its width along the X axis. The second fluorescent member 112 absorbs light emitted from the plurality of light-emitting elements 21 as excitation light and emits fluorescence. The second fluorescent member 112 has a second incident surface S21, a second supporting surface S22, a second end surface S23, and a second exit surface S24. The second fluorescent member 112 is disposed in the +Z direction of the first fluorescent member 111. The second fluorescent member 112 is disposed in the arrangement direction of the first fluorescent member 111. The second fluorescent member 112 is connected to the first fluorescent member 111. The second fluorescent member 112 corresponds to an example of a second element member.

[0042] The second incident surface S21 is a surface of the second fluorescent member 112 in the +Y direction. The second incident surface S21 faces the plurality of light-emitting elements 21 included in the light-emitting unit 20. The second incident surface S21 receives light emitted from the plurality of light-emitting elements 21. The second incident surface S21 forms a part of the upper surface S1 of the first phosphor 11a. The second incident surface S21 corresponds to an example of a second element incident surface.

[0043] The second support surface S22 is the surface of the second fluorescent member 112 facing the -Y direction. The second support surface S22 comes into contact with the collector support part 30a and is cooled by the support body 30. The second support surface S22 forms part of the lower surface S2 of the first fluorescent member 11a.

[0044] The second end surface S23 is the surface of the second fluorescent member 112 in the -Z direction. The second end surface S23 totally reflects the excitation light and fluorescence propagating within the second fluorescent member 112. The second end surface S23 faces the first emission surface S14 of the first fluorescent member 111. The second end surface S23 is connected to the first emission surface S14 directly or via an adhesive or the like. The fluorescence emitted from the first emission surface S14 is incident on the second end surface S23. The second end surface S23 corresponds to an example of a second coupling surface.

[0045] The second exit surface S24 is the surface of the second fluorescent member 112 in the +Z direction. The second exit surface S24 emits fluorescent light toward the optical element 15. The second exit surface roughness, which is the surface roughness of the second exit surface S24, is configured to be rougher than the second incident surface roughness, which is the surface roughness of the second incident surface S21. The second exit surface roughness is configured to be rougher than the surface roughness of the second support surface S22. The second exit surface roughness is configured to be rougher than the surface roughness of both side surfaces of the second fluorescent member 112. By configuring the second exit surface roughness to be rougher than the surface roughness of the other surfaces, the amount of fluorescent light emitted from the second exit surface S24 is greater than when the second exit surface roughness is configured to be equal to the surface roughness of the other surfaces. The second exit surface S24 corresponds to the light-emitting end surface S4 of the first phosphor 11a.

[0046] The light-emitting end surface S4 is a surface of the first phosphor 11a in the +Z direction. The light-emitting end surface S4 is a surface that intersects with the upper surface S1 of the first phosphor 11a. The light-emitting end surface S4 emits the fluorescent light propagating within the first phosphor 11a. The light-emitting end surface S4 emits the fluorescent light to the optical element 15. The light-emitting end surface S4 corresponds to an example of an emission surface.

[0047] The first fluorescent member 11a is formed by connecting the first exit surface S14 of the first fluorescent member 111 and the second end surface S23 of the second fluorescent member 112. The first exit surface S14 and the second end surface S23 are connected directly or via a light-transmitting adhesive or the like. The first exit surface S14 and the second end surface S23 are preferably connected with a light-transmitting adhesive. By connecting the first exit surface S14 and the second end surface S23 with a light-transmitting adhesive, a decrease in the amount of light at the connection portion is suppressed.

[0048] The adhesive preferably has a high refractive index, high heat resistance, and high light transmittance. The refractive index of the transparent phosphor ceramic is around 1.83. The refractive index of the adhesive is preferably close to 1.83. Since the first phosphor 11a may reach approximately 150°C, the adhesive preferably has a heat resistance of around 150°C. Since fluorescence passes through the adhesive, the adhesive preferably has high light transmittance. The adhesive may be an epoxy resin, an acrylic resin, or a silicone resin.

[0049] The phosphor 11, which includes the first phosphor 11a, generates heat by absorbing excitation light and emitting fluorescence. The lower surface S2 is cooled by the support 30. The generation of heat and cooling cause a temperature difference within the phosphor 11. If the phosphor 11 is made up of a single member, the temperature difference makes it more likely that deformation such as warping, or damage such as internal cracks or surface scratches will occur in the phosphor 11. By connecting the first fluorescent member 111 and the second fluorescent member 112 to form the first phosphor 11a, deformation and damage are suppressed.

[0050] The lighting device 1 includes a plurality of light-emitting elements 21 arranged in an arrangement direction and emitting output light, a first phosphor 11a having an upper surface S1 facing the plurality of light-emitting elements 21 and onto which the output light is incident, and a light-emitting end surface S4 intersecting the upper surface, and converting the wavelength of the light, and a support 30 for cooling a lower surface S2 different from the upper surface S1 of the first phosphor 11a. The first phosphor 11a is composed of a first fluorescent member 111 and a second fluorescent member 112 arranged in the arrangement direction of the first fluorescent member 111 and connected to the first fluorescent member 111. First fluorescent body 11a is configured by connecting first fluorescent member 111 and second fluorescent member 112, so that deformation and damage of first fluorescent body 11a due to temperature differences within first fluorescent body 11a are suppressed.

[0051] The first fluorescent member 111 has a first exit surface S14 facing the second fluorescent member 112, and a first incident surface S11 that constitutes a part of the top surface S1. The second fluorescent member 112 has a second end surface S23 facing the first exit surface S14, and a second incident surface S21 that constitutes a part of the top surface S1. The first exit surface S14 and the second end surface S23 are preferably connected with a light-transmitting adhesive. By connecting the first exit surface S14 and the second end surface S23 with a light-transmitting adhesive, a decrease in the amount of light at the connection portion is suppressed.

[0052] The first exit surface roughness of the first exit surface S14 is preferably greater than the first entrance surface roughness of the first entrance surface S11. By configuring the first exit surface roughness to be rougher than the first entrance surface roughness, the amount of fluorescent light emitted from the first exit surface S14 becomes greater than when the first exit surface roughness is configured to be equal to the first entrance surface roughness.

[0053] The first fluorescent body 11a, which is arranged opposite a plurality of light-emitting elements 21 arranged in an arrangement direction and emitting light, and the support body 30, has a first fluorescent member 111 and a second fluorescent member 112 arranged in the arrangement direction of the first fluorescent member 111 and connected to the first fluorescent member 111. First fluorescent body 11a is configured by connecting first fluorescent member 111 and second fluorescent member 112, so that deformation and damage of first fluorescent body 11a due to temperature differences within first fluorescent body 11a are suppressed.

[0054] Fig. 5 shows a cross-sectional configuration of the phosphor 11 and the light-emitting unit 20. Fig. 5 schematically shows the cross-sectional configuration of the phosphor 11 and the light-emitting unit 20. Fig. 5 shows a YZ cross section of the phosphor 11 and the light-emitting unit 20. Fig. 5 shows a second phosphor 11b as the phosphor 11. The multiple light-emitting elements 21 included in the light-emitting unit 20 are arranged in an arrangement direction parallel to the optical axis AX.

[0055] The second phosphor 11b is an example of the phosphor 11. The second phosphor 11b is composed of a first fluorescent member 111, a second fluorescent member 112, and a third fluorescent member 113. The second phosphor 11b is formed by connecting the first fluorescent member 111, the second fluorescent member 112, and the third fluorescent member 113. The configurations of the first fluorescent member 111 and the second fluorescent member 112 included in the second phosphor 11b are the same as the first fluorescent member 111 and the second fluorescent member 112 included in the first phosphor 11a. The functions of the respective surfaces of the first fluorescent member 111 and the second fluorescent member 112 included in the second phosphor 11b are the same as the functions of the respective surfaces of the first fluorescent member 111 and the second fluorescent member 112 included in the first phosphor 11a, except for the first end surface S13 of the first fluorescent member 111.

[0056] The third fluorescent member 113 is made of transparent phosphor ceramic. The third fluorescent member 113 is a rectangular parallelepiped whose length along the Z axis is greater than its width along the X axis. The third fluorescent member 113 absorbs the light emitted from the plurality of light-emitting elements 21 as excitation light and emits fluorescence. The third fluorescent member 113 has a third incident surface S31, a third support surface S32, a third end surface S33, and a third exit surface S34. The third fluorescent member 113 is disposed in the -Z direction relative to the first fluorescent member 111. The third fluorescent member 113 is disposed in the opposite direction to the arrangement direction relative to the first fluorescent member 111. The third fluorescent member 113 is connected to the first fluorescent member 111. The third fluorescent member 113 corresponds to an example of a third element member.

[0057] The third incident surface S31 is a surface of the third fluorescent member 113 in the +Y direction. The third incident surface S31 faces the plurality of light-emitting elements 21 included in the light-emitting unit 20. The third incident surface S31 receives light emitted from the plurality of light-emitting elements 21. The third incident surface S31 constitutes a part of the upper surface S1 of the second phosphor 11b.

[0058] The third support surface S32 is the surface of the third fluorescent member 113 facing the -Y direction. The third support surface S32 comes into contact with the collector support part 30a and is cooled by the support body 30. The third support surface S32 forms part of the lower surface S2 of the second phosphor 11b.

[0059] The third end surface S33 is the surface of the third fluorescent member 113 in the -Z direction. The third end surface S33 corresponds to the reflective end surface S3 of the second fluorescent body 11b. The third end surface S33 totally reflects the excitation light and fluorescence propagating within the third fluorescent member 113.

[0060] The third exit surface S34 is the surface of the third fluorescent member 113 in the +Z direction. The third exit surface S34 emits fluorescence toward the first fluorescent member 111. It is preferable that the third exit surface S34 is subjected to a surface treatment such as a microfabrication treatment or a roughening treatment. The surface treatment makes it easier for the fluorescence to be emitted from the third exit surface S34.

[0061] As an example, the third exit surface S34 is subjected to a roughening treatment such as surface polishing. When the third exit surface S34 is roughened, the third exit surface roughness, which is the surface roughness of the third exit surface S34, is configured to be rougher than the third entrance surface roughness, which is the surface roughness of the third entrance surface S31. The third exit surface roughness is configured to be rougher than the surface roughness of the third support surface S32 and the surface roughness of the third end surface S33. The third exit surface roughness is configured to be rougher than the surface roughness of both side surfaces of the third fluorescent member 113. By configuring the third exit surface roughness to be rougher than the surface roughness of the other surfaces, the amount of fluorescent light emitted from the third exit surface S34 is greater than when the third exit surface roughness is configured to be equal to the surface roughness of the other surfaces. The third exit surface S34 faces the first fluorescent member 111.

[0062] The first end surface S13 of the first fluorescent member 111 included in the second fluorescent material 11b faces the third exit surface S34 of the third fluorescent member 113. The first end surface S13 is connected to the third exit surface S34 directly or via an adhesive or the like. The fluorescence emitted from the third exit surface S34 is incident on the first end surface S13.

[0063] By configuring second phosphor 11b from three fluorescent materials, the length along the Z axis of each transparent phosphor ceramic is shorter than the length along the Z axis of the transparent phosphor ceramic when phosphor 11 is configured from one or two transparent phosphor ceramics. When the length along the Z axis of each transparent phosphor ceramic is shorter, deformation and breakage due to temperature differences are less likely to occur.

[0064] The second fluorescent body 11b is preferably arranged in the opposite direction to the arrangement direction of the first fluorescent members 111 and has a third fluorescent member 113 connected to the first fluorescent members 111. The second phosphor 11b is less likely to be deformed or damaged due to temperature differences.

[0065] 5 shows the second phosphor 11b made up of three fluorescent members, but is not limited to this. The phosphor 11 may be made up of four or more fluorescent members. The number of fluorescent members can be set appropriately.

[0066] 6A and 6B show the surface structure of the first exit surface S14 of the first fluorescent member 111. FIGS. 6A and 6B show an enlarged cross section of the first exit surface S14 of the first phosphor 11a. FIGS. 6A and 6B show the first exit surface S14 processed into a first microstructure MS1. The microstructure including the first microstructure MS1 corresponds to an example of a surface shape. FIG. 6A shows an enlarged ZY cross section of the first exit surface S14. FIG. 6B shows a ZX cross section of the first exit surface S14.

[0067] The first microstructure MS1 is a structure in which multiple hemispheres are arranged on the first emission surface S14. The first microstructure MS1 is composed of multiple hemispheres. A hemisphere corresponds to an example of a spherical shape. The first microstructure MS1 is processed by a processing process such as laser processing. Multiple hemispheres are arranged on the first emission surface S14 along the Y-axis and X-axis. The hemispheres are formed over the entire surface of the first emission surface S14. By forming the first emission surface S14 from the first microstructure MS1, the adhesive strength of the adhesive is improved. Furthermore, when an adhesive with a refractive index different from that of the first fluorescent member 111 is used, fluorescence is more likely to be emitted toward the adhesive.

[0068] 6A and 6B is configured on the first light exit surface S14, but is not limited thereto. The first light exit surface S34 of the third fluorescent member 113 shown in FIG. 5 may also be configured on the third light exit surface S34.

[0069] 7A and 7B show the surface structure of the first exit surface S14 of the first fluorescent member 111. FIGS. 7A and 7B show an enlarged cross section of the first exit surface S14 of the first phosphor 11a. FIGS. 7A and 7B show the first exit surface S14 processed into the second microstructure MS2. The second microstructure MS2 corresponds to an example of a surface shape. FIG. 7A shows an enlarged ZY cross section of the first exit surface S14. FIG. 7B shows a ZX cross section of the first exit surface S14.

[0070] The second microstructure MS2 has a structure in which multiple triangular pyramids are arranged on the first emission surface S14. The second microstructure MS2 is composed of multiple triangular pyramids. The triangular pyramids correspond to an example of a triangular pyramid shape. The second microstructure MS2 is processed by a processing process such as laser processing. Multiple triangular pyramids are arranged on the first emission surface S14 along the Y-axis and X-axis. The triangular pyramids are formed over the entire surface of the first emission surface S14. By forming the first emission surface S14 from the second microstructure MS2, the adhesive strength of the adhesive is improved. Furthermore, when an adhesive with a refractive index different from that of the first fluorescent member 111 is used, the fluorescence is more likely to be emitted toward the adhesive. The second microstructure MS2 is composed of multiple triangular pyramids, but is not limited to this. The second microstructure MS2 may also be composed of multiple polygonal pyramids, such as square pyramids.

[0071] 7A and 7B, the second microstructure MS2 is formed on the first light exit surface S14, but is not limited thereto. The second microstructure MS2 may be formed on the third light exit surface S34 of the third fluorescent member 113 shown in FIG.

[0072] 8A and 8B show the surface structure of the first exit surface S14 of the first fluorescent member 111. FIGS. 8A and 8B show an enlarged cross section of the first exit surface S14 of the first phosphor 11a. FIGS. 8A and 8B show the first exit surface S14 processed into a third microstructure MS3. The third microstructure MS3 corresponds to an example of a surface shape. FIG. 8A shows an enlarged ZY cross section of the first exit surface S14. FIG. 8B shows a ZX cross section of the first exit surface S14.

[0073] The third microstructure MS3 has a structure in which multiple triangular prisms are arranged on the first light output surface S14. The third microstructure MS3 is composed of multiple triangular prisms. The triangular prisms correspond to an example of a prism shape. The third microstructure MS3 is processed by a processing process such as laser processing. Multiple triangular prisms are arranged along the Y axis on the first light output surface S14. The triangular prisms are formed over the entire surface of the first light output surface S14. By forming the first light output surface S14 with the third microstructure MS3, the adhesive strength of the adhesive is improved. Furthermore, when an adhesive with a refractive index different from that of the first fluorescent member 111 is used, the fluorescence is more likely to be emitted toward the adhesive. The third microstructure MS3 has multiple triangular prisms arranged along the Y axis, but is not limited to this. The multiple triangular prisms may be arranged along the X axis or any other axis.

[0074] 8A and 8B is configured on the first light exit surface S14, but is not limited thereto. The third light exit surface S34 of the third fluorescent member 113 shown in FIG. 5 may also be configured on the third light exit surface S34.

[0075] Fig. 9 shows the evaluation results of each microstructure. Fig. 9 shows the evaluation results when surface treatment was performed on the first emission surface S14. Fig. 9 shows the evaluation results of the first phosphor 11a using the first fluorescent member 111 that was subjected to each surface treatment. Fig. 9 shows the amount of light emitted by the first phosphor 11a when the same amount of light is emitted from multiple light-emitting elements 21 to the first phosphor 11a. The light emitted by the first phosphor 11a is fluorescent light converted to a predetermined wavelength.

[0076] FIG. 9 shows the evaluation results of the first phosphor 11a using the first fluorescent member 111 processed into the first microstructure MS1. FIG. 9 shows the evaluation results of the first phosphor 11a using the first fluorescent member 111 processed into the second microstructure MS2. FIG. 9 shows the evaluation results of the first phosphor 11a using the first fluorescent member 111 processed into the third microstructure MS3. FIG. 9 shows the evaluation results of the first phosphor 11a using the first fluorescent member 111 processed into a mirror structure. The mirror structure is formed by performing a mirror finish treatment such as surface polishing on the first exit surface S14. The mirror structure is a surface structure in which irregular concaves and convexes are formed.

[0077] 9 shows relative values ​​based on the output value of light output by the first phosphor 11a using the first fluorescent member 111 processed into a mirror structure. When a joint is provided in the phosphor 11, the amount of light emitted from the phosphor 11 decreases. By processing the first exit surface S14 into a mirror structure, the decrease in the amount of light is suppressed. By processing the first exit surface S14 into the first microstructure MS1, the second microstructure MS2, and the third microstructure MS3, the decrease in the amount of light output is suppressed more than with a mirror structure.

[0078] The microstructure of the first emission surface S14 is preferably formed of one of a hemisphere, a triangular pyramid, and a triangular prism. By forming the first emission surface S14 from any one of the first microstructure MS1, the second microstructure MS2, and the third microstructure MS3, a decrease in the amount of light emitted from the first phosphor 11a is suppressed.

[0079] FIG. 10 shows the cross-sectional configuration of the phosphor 11 and the light-emitting unit 20. FIG. 10 schematically shows the cross-sectional configuration of the phosphor 11 and the light-emitting unit 20. FIG. 10 shows the YZ cross section of the phosphor 11 and the light-emitting unit 20. FIG. 10 shows a third phosphor 11c as the phosphor 11. The multiple light-emitting elements 21 included in the light-emitting unit 20 are arranged in an arrangement direction parallel to the optical axis AX. FIG. 10 shows a virtual axis VL that is perpendicular to the arrangement direction and the optical axis AX. The virtual axis VL corresponds to an example of an orthogonal axis.

[0080] The third fluorescent member 11c is an example of the fluorescent member 11. The third fluorescent member 11c is composed of a first fluorescent member 111 and a second fluorescent member 112. The third fluorescent member 11c is formed by connecting the first fluorescent member 111 and the second fluorescent member 112. The first fluorescent member 111 shown in FIG. 10 has the same configuration as the first fluorescent member 111 shown in FIG. 4 except for the configuration of the first exit surface S14. The second fluorescent member 112 shown in FIG. 10 has the same configuration as the second fluorescent member 112 shown in FIG. 4 except for the configuration of the second end surface S23.

[0081] The first exit surface S14 is an inclined surface inclined at an inclination angle θ with respect to the virtual axis VL. The inclination angle θ corresponds to an example of a predetermined angle. The inclination angle θ is an angle different from 0 degrees. When the first exit surface S14 has an inclination angle θ with respect to the virtual axis VL, the surface area of ​​the first exit surface S14 is larger than when the first exit surface S14 does not have the inclination angle θ. When the surface area of ​​the first exit surface S14 is increased, the bonding surface area with the adhesive increases. The connection strength at the connection portion is increased. The inclination angle θ is preferably in the range of 5 to 30 degrees. When the inclination angle θ is less than 5 degrees, the effect of improving the connection strength is small. When the inclination angle θ is greater than 30 degrees, the amount of light propagating from the first fluorescent member 111 to the second fluorescent member 112 decreases.

[0082] The second end surface S23 is configured at an angle corresponding to the inclination angle θ. The second end surface S23 is inclined at an angle such that the first fluorescent member 111 and the second fluorescent member 112 are arranged parallel to the Z axis when the first fluorescent member 111 and the second fluorescent member 112 are connected.

[0083] The first emission surface S14 is preferably an inclined surface inclined at an inclination angle θ with respect to a virtual axis VL perpendicular to the arrangement direction. The first light exit surface S14 is an inclined surface, so that the strength of the connection by the adhesive increases.

[0084] 10, the first exit surface S14 of the first fluorescent member 111 constituting the third fluorescent body 11c is configured as an inclined surface, but is not limited to this. The first exit surface S14 of the first fluorescent member 111 and the third exit surface S34 of the third fluorescent member 113 constituting the second fluorescent body 11b shown in FIG. 5 may also be configured as inclined surfaces. [Explanation of symbols]

[0085] 1...lighting device, 10...light collecting body, 11...phosphor, 11a...first phosphor, 11b...second phosphor, 11c...third phosphor, 15...optical element, 20...light emitting unit, 21...light emitting element, 30...support, 30a...light collecting body support portion, 50...cooling element body, 111...first fluorescent member, 112...second fluorescent member, 113...third fluorescent member, AX...optical axis, MS1...first microstructure, MS2...second microstructure, MS3...third microstructure Structure, S1...Top surface, S2...Bottom surface, S3...Reflection end surface, S4...Emission end surface, S5...First side surface, S6...Second side surface, S11...First incidence surface, S12...First support surface, S13...First end surface, S14...First emission surface, S21 ...Second incidence surface, S22...Second support surface, S23...Second end surface, S24...Second exit surface, S31...Third entrance surface, S32...Third support surface, S33...Third end surface, S34...Third exit surface, VL...Virtual axis, θ...Inclination angle.

Claims

1. a plurality of solid-state light sources arranged in an arrangement direction and emitting light; a wavelength conversion element having an incident surface facing the plurality of solid-state light sources and through which the light is incident, and an exit surface intersecting the incident surface, and converting the wavelength of the light; a cooling member that cools a surface of the wavelength conversion element other than the incident surface, the wavelength conversion element is composed of a first element member and a second element member arranged in the arrangement direction of the first element members and connected to the first element members; Lighting equipment.

2. the first element member has a first coupling surface facing the second element member and a first element incident surface constituting a part of the incident surface, the second element member has a second coupling surface opposite to the first coupling surface and a second element incident surface constituting a part of the incident surface, The first connecting surface and the second connecting surface are connected with a light-transmitting adhesive. The lighting device according to claim 1 .

3. a surface roughness of the first coupling surface is greater than a surface roughness of the first element incident surface; 3. The lighting device according to claim 2.

4. The surface shape of the first connecting surface is one of a spherical shape, a triangular pyramid shape, and a prism shape.

4. The lighting device according to claim 3.

5. the first connecting surface is an inclined surface inclined at a predetermined angle with respect to an orthogonal axis perpendicular to the arrangement direction; 3. The lighting device according to claim 2.

6. the wavelength conversion element includes a third element member that is arranged in a direction opposite to the arrangement direction with respect to the first element member and is connected to the first element member; The lighting device according to claim 1 .

7. A wavelength conversion element is disposed opposite a plurality of solid-state light sources that are arranged in an arrangement direction and emit light, and a cooling member, a first element member; and a second element member arranged in the arrangement direction of the first element member and connected to the first element member; Wavelength conversion element.

Images