Wavelength conversion member, manufacturing method thereof, and light emitting device

Abstract

To provide a wavelength conversion member having a wavelength conversion unit including a plurality of light emitting units, the wavelength conversion member being more efficient in suppressing propagation of light from light emitting units next to each other, and to provide a method for manufacturing the wavelength conversion member.SOLUTION: A method for manufacturing a wavelength conversion member according to one embodiment of the present disclosure includes the steps of: alternately laminating a laminate body and a ceramic sheet with a fluorescent body to form a complex, the laminate body being formed by laminating a green sheet with a reflection member, a green sheet with a light shielding member, and a green sheet with a reflection member in that order; and pressing and burning the complex.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present disclosure relates to a wavelength conversion member, a method for manufacturing the same, and a light emitting device. [Background technology]

[0002] Patent Document 1 discloses a device including a phosphor ceramic on which light from multiple light-emitting diodes is incident. This device has a light barrier within the phosphor ceramic to reduce lateral light propagation. The phosphor ceramic is formed, for example, by repeatedly folding, slicing, and firing two or more layer films composed of a phosphor ceramic precursor and a light barrier / reflector / scatterer. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Special Publication No. 2021-507307 Summary of the Invention [Problem to be solved by the invention]

[0004] The present disclosure aims to provide a wavelength conversion member that includes a wavelength conversion unit containing multiple light-emitting units and that has an improved effect of suppressing light propagation from adjacent light-emitting units, a method for manufacturing the same, and a light-emitting device that includes the wavelength conversion member. [Means for solving the problem]

[0005] A method for manufacturing a wavelength conversion member according to one embodiment of the present disclosure includes the steps of: forming a composite by alternately stacking a laminate in which a green sheet having a reflective member, a green sheet having a light-shielding member, and a green sheet having a reflective member are stacked in this order, with a ceramic sheet having a phosphor; and pressurizing and firing the composite.

[0006] A wavelength conversion member according to one embodiment of the present disclosure includes a plurality of light-emitting sections whose main material is a ceramic containing a phosphor, and a plurality of laminates in which a light-reflecting layer, a light-blocking layer, and a light-reflecting layer are laminated in this order, and the laminates and the light-emitting sections are arranged alternately in the stacking direction of the laminates.

[0007] A light emitting device according to an embodiment of the present disclosure includes a plurality of semiconductor laser elements and a wavelength conversion member according to an embodiment of the present disclosure, wherein light emitted from each of the plurality of semiconductor laser elements is incident on a different light emitting unit, and each of the light emitting units converts the incident light into light of a different wavelength. [Effects of the Invention]

[0008] According to an embodiment of the present disclosure, it is possible to provide a wavelength conversion member including a wavelength conversion unit including a plurality of light emitting units and having an improved effect of suppressing propagation of light from adjacent light emitting units, a method for manufacturing the same, and a light emitting device including the wavelength conversion member. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 2 is a perspective view of a wavelength conversion member according to the first embodiment. [Figure 2] 1A to 1C are views (part 1) illustrating a method for manufacturing a wavelength conversion member according to the first embodiment. [Figure 3] FIG. 4 is a view (part 2) illustrating the method for manufacturing a wavelength conversion member according to the first embodiment. [Figure 4] FIG. 4 is a view (part 3) illustrating the method for manufacturing a wavelength conversion member according to the first embodiment. [Figure 5] FIG. 4 is a view (part 4) illustrating the method for manufacturing a wavelength conversion member according to the first embodiment. [Figure 6] FIG. 5 is a view (part 5) illustrating the method for manufacturing a wavelength conversion member according to the first embodiment. [Figure 7] FIG. 6 is a view (part 6) illustrating the method for manufacturing a wavelength conversion member according to the first embodiment. [Figure 8]FIG. 7 is a view (part 7) illustrating the method for manufacturing a wavelength conversion member according to the first embodiment. [Figure 9] FIG. 10 is a perspective view of a wavelength conversion member according to Modification 1 of the first embodiment. [Figure 10] FIG. 10 is a perspective view of a wavelength conversion member according to a second modified example of the first embodiment. [Figure 11] FIG. 11 is a perspective view of a wavelength conversion member according to a third modification of the first embodiment. [Figure 12] FIG. 10 is a perspective view of a wavelength conversion member according to a second embodiment. [Figure 13] FIG. 10 is a top view of a light emitting device according to a third embodiment. [Figure 14] 14 is a cross-sectional view of the light emitting device taken along the line XIV-XIV in FIG. 13. [Figure 15] FIG. 10 is a top view of the light emitting device according to the third embodiment, from which a wavelength conversion member, a light-transmitting member, and a light-blocking member have been removed. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, an embodiment of the invention will be described with reference to the drawings. In the following description, terms indicating specific directions or positions (e.g., "upper," "lower," and other terms including these terms) will be used as necessary. However, the use of these terms is intended to facilitate understanding of the invention with reference to the drawings, and the meaning of these terms does not limit the technical scope of the present invention. Furthermore, parts that appear with the same reference numerals in multiple drawings indicate the same or equivalent parts or components.

[0011] Furthermore, in this disclosure, polygons such as triangles and quadrilaterals are referred to as polygons, including shapes in which the corners of the polygons have been processed, such as by rounding, chamfering, corner removal, or rounding. Shapes in which processing has been applied not only to the corners (edges of the sides) but also to the middle portions of the sides are also referred to as polygons. In other words, shapes in which partial processing has been applied while retaining the polygon as a base are included in the interpretation of "polygon" described in this disclosure.

[0012] The same applies to words that represent specific shapes, such as trapezoids, circles, and irregularities, not just polygons. The same also applies when dealing with the sides that form the shape. In other words, even if the corners or middle part of a side have been processed, the interpretation of "side" includes the processed part. Note that when distinguishing a "polygon" or "side" that has no processing from a processed shape, the word "strict" is added, for example, "strict quadrangle."

[0013] Furthermore, the embodiments shown below are intended to exemplify wavelength conversion members and the like to embody the technical concepts of the present invention, and are not intended to limit the present invention thereto. Furthermore, unless otherwise specified, the dimensions, materials, shapes, relative positions, etc. of the components described below are intended for illustrative purposes only and are not intended to limit the scope of the present invention. Furthermore, the content described in one embodiment can also be applied to other embodiments and modified examples. Furthermore, the size and positional relationships of components shown in the drawings may be exaggerated for clarity. Furthermore, to avoid overly complex drawings, schematic diagrams may be used in which some elements are omitted, or end views may be used as cross-sectional views showing only the cut surface.

[0014] First Embodiment FIG. 1 is a perspective view of a wavelength conversion member according to a first embodiment. As shown in FIG. 1, the wavelength conversion member 10 includes a plurality of light-emitting sections 20 and a plurality of laminates 30. Each component of the wavelength conversion member 10 will be described. For reference, an X-axis, a Y-axis, and a Z-axis, which are perpendicular to each other, are shown in FIG. 1. The directions parallel to the X-axis, the Y-axis, and the Z-axis are defined as a first direction X, a second direction Y, and a third direction Z, respectively.

[0015] (Light emitting unit 20) The light-emitting unit 20 has an upper surface, a lower surface opposite the upper surface, and a plurality of side surfaces intersecting the upper and lower surfaces. In FIG. 1, in each light-emitting unit 20, the third direction Z is a direction perpendicular to the upper surface and / or the lower surface. The plurality of side surfaces are connected to the outer edge of the upper surface and the outer edge of the lower surface. The shape of each light-emitting unit 20 is, for example, a rectangular parallelepiped. Furthermore, the upper surface of each light-emitting unit 20 is rectangular. In the example of FIG. 1, each light-emitting unit 20 is a cube. The upper surface, lower surface, and four side surfaces of each light-emitting unit 20 are all square. However, the shape of the light-emitting unit 20 is not limited to this.

[0016] Each light-emitting unit 20 may have either its upper or lower surface as a light incident surface, and either its lower or upper surface as a light exit surface. It can convert light of a predetermined wavelength incident on the light incident surface into light of a different wavelength, and emit the converted light from the light exit surface. Each light-emitting unit 20 may emit a portion of the incident light. Each light-emitting unit 20 may also convert all of the incident light into light of a different wavelength. In this case, the light incident on each light-emitting unit 20 is not emitted from each light-emitting unit 20.

[0017] Since each light-emitting section 20 is irradiated with light, it is preferable that the base material of each light-emitting section 20 be formed using, as the main material, an inorganic material that is not easily decomposed by light irradiation. The main material is, for example, ceramic. Examples of ceramics used as the main material include aluminum oxide, aluminum nitride, silicon oxide, yttrium oxide, zirconium oxide, and magnesium oxide. It is preferable to select a material with a melting point of 1200°C to 2500°C as the main ceramic material so that each light-emitting section 20 does not undergo deterioration such as deformation or discoloration due to heat. The light-emitting section 20 is, for example, a sintered body formed using ceramic as the main material.

[0018] Each light-emitting section 20 can be formed, for example, by sintering a phosphor and a translucent material such as aluminum oxide. The phosphor content can be 0.05% to 50% by volume with respect to the total volume of the ceramic. Alternatively, for example, ceramic consisting essentially of phosphor, obtained by sintering phosphor powder, may be used. Alternatively, each light-emitting section 20 may be formed from a single crystal of phosphor.

[0019] Examples of phosphors include cerium-activated yttrium aluminum garnet (YAG), cerium-activated lutetium aluminum garnet (LAG), europium-activated silicate ((Sr,Ba)2SiO4), α-sialon phosphor, and β-sialon phosphor. Among these, YAG phosphor has good heat resistance. Thus, each light-emitting section 20 is mainly made of ceramic containing a phosphor.

[0020] For example, when each light-emitting section 20 has a YAG phosphor, when blue excitation light is incident from the bottom surface, the blue excitation light and yellow fluorescence are combined to emit white light from the top surface.

[0021] (Laminate 30) Each laminate 30 has a structure in which a light-reflecting layer 31, a light-shielding layer 32, and another light-reflecting layer 31 are laminated in this order. In Fig. 1, instead of assigning reference numerals to all of the light-reflecting layers 31 and light-shielding layers 32, the light-reflecting layers 31 and the light-shielding layers 32 are indicated by dot patterns with different densities.

[0022] The light reflecting layer 31 has light reflectivity. The light reflecting layer 31 has a reflectance of 70% or more with respect to light incident from the light emitting section 20. The light reflecting layer 31 more preferably has a reflectance of 80% or more. The film thickness of the light reflecting layer 31 is, for example, 30 μm or more and 1000 μm or less.

[0023] The light reflecting layer 31 is mainly made of, for example, ceramic. Examples of ceramics used as the main material include aluminum oxide, yttrium oxide, titanium oxide, zirconium oxide, and silicon oxide. The light reflecting layer 31 may also be made of a material other than ceramic.

[0024] The light-shielding layer 32 has the property of blocking or attenuating incident light. The light-shielding layer 32 preferably has a transmittance of 20% or less for incident light, more preferably 15% or less. By setting the light transmittance of the light-shielding layer 32 in this range, it is possible to suppress light interference between the light-emitting sections 20, which will be described later. The light-shielding layer 32 may also be formed by incorporating a light absorber into its configuration. In this case, the light-shielding layer 32 preferably has an absorptance of 70% or more for light incident through the light-reflecting layer 31, more preferably an absorptance of 80% or more. Such a configuration can further enhance the above-mentioned effects. The light-shielding layer 32 does not necessarily have to include a light absorber. The film thickness of the light-shielding layer 32 is, for example, 30 μm or more and 1000 μm or less.

[0025] The light-shielding layer 32 is a layer whose main material is the same ceramic as the main material forming the light-reflecting layer 31, and further contains a dark-colored ceramic that absorbs light. Examples of dark colors include black, brown, dark blue, and gray. Among these, black, which has a high light absorption rate, is preferred. By using the same ceramic as the main material of the light-reflecting layer 31 as the main material of the light-shielding layer 32, the possibility of cracks, breakage, etc. occurring due to differences in shrinkage rates during sintering in the manufacturing process of the wavelength conversion member 10, which will be described later, can be reduced. The main material of the light-shielding layer 32 may be a ceramic different from the main material of the light-reflecting layer 31. Examples of ceramics used as the main material of the light-shielding layer 32 include aluminum oxide, yttrium oxide, titanium oxide, zirconium oxide, and silicon oxide, which are listed as examples of ceramics used as the main material of the light-reflecting layer 31. Furthermore, examples of dark-colored ceramics that may be included in the light-shielding layer 32 together with the main ceramic include ruthenium oxide, aluminum nitride, and silicon nitride. In this specification, ceramics having the property of absorbing light are included in the light absorber. Note that the light-shielding layer 32 may be formed from a material other than ceramic.

[0026] (wavelength conversion member 10) 1, in the laminate 30, a light reflecting layer 31, a light blocking layer 32, and a light reflecting layer 31 are stacked in a first direction X (hereinafter, the first direction X in FIG. 1 may be referred to as the stacking direction). In the wavelength conversion member 10, the light emitting sections 20 and the laminates 30 are arranged alternately in the stacking direction of the laminate 30. That is, in the wavelength conversion member 10, the laminates 30 are arranged between the light emitting sections 20 adjacent to each other in the stacking direction, and the light emitting sections 20 are spaced apart from each other with the laminates 30 sandwiched between them. The light emitting sections 20 are arranged, for example, such that the centers of the light emitting sections 20 are aligned on a straight line parallel to the stacking direction when viewed from above.

[0027] In the illustrated wavelength conversion member 10, of the multiple light emitting sections 20, two light emitting sections 20 located at both ends in the stacking direction (first direction X) have a light reflecting layer 31 provided on the side opposite to the side in contact with the stacked body 30. In the illustrated example, light reflecting layers 31 are provided on both ends of the wavelength conversion member 10. In a plan view seen from the stacking direction, the light reflecting layer 31 provided in contact with the light emitting sections 20 becomes the side of the wavelength conversion member 10. Of the light reflecting layers 31 located at both ends, no light-shielding layer 32 is provided on the side opposite to the side in contact with the light emitting sections 20. Note that the wavelength conversion member is not limited to a form in which light reflecting layers 31 are provided on both ends, and various forms are possible, as will be described later.

[0028] The wavelength conversion member 10 has a square rod-like shape when viewed from the stacking direction. Here, rod-like refers to a shape that extends elongatedly along the stacking direction. The planar shape of the wavelength conversion member 10 when viewed from the stacking direction does not have to be square. It is preferable that the lengths of the light-emitting sections 20 in the stacking direction are equal. It is also preferable that the lengths of the laminates 30 in the stacking direction are equal. This allows the pitch of the light-emitting sections 20 in the wavelength conversion member 10 to be uniform. Here, "equal" means that a difference of ±10% is allowed. The pitch of the light-emitting sections 20 can be, for example, 0.1 mm or more and 2.0 mm or less. The variation in the pitch of the light-emitting sections 20 can be, for example, ±5% or less of the average pitch of the light-emitting sections 20.

[0029] In the stacking direction, the length of the laminate 30 is preferably shorter than the length of the light-emitting sections 20. By doing so, the pitch of the light-emitting sections 20 in the wavelength conversion member 10 can be narrowed. Note that in the stacking direction, the length of the laminate 30 may be the same as or longer than the length of the light-emitting sections 20. In the stacking direction, the length of the light-emitting sections 20 is, for example, 0.3 mm or more and 2.0 mm or less. More preferably, it is 0.5 mm or more and 1.5 mm or less. In the stacking direction, the length of the laminate 30 is, for example, 0.1 mm or more and 2.0 mm or less. In the stacking direction, the length of the laminate 30 may be 1 / 2 or more and 2 times or less the length of the light-emitting sections 20.

[0030] The wavelength conversion member 10 has a plurality of light emitting sections 20, and a laminate 30 is disposed between adjacent light emitting sections 20. This makes it possible to suppress interference between the lights when the lights are incident on adjacent light emitting sections 20. This will be described in detail below.

[0031] In each light-emitting section 20, the light-reflecting layer 31 is disposed in contact with two side surfaces intersecting the stacking direction. As a result, light that has been wavelength-converted by the phosphor contained in each light-emitting section 20 and emitted from the side surface of each light-emitting section 20 toward the light-reflecting layer 31 is reflected back to each light-emitting section 20. Also, light that has entered each light-emitting section 20, is not wavelength-converted in each light-emitting section 20, and is emitted from the side surface of each light-emitting section 20 toward the light-reflecting layer is reflected back to each light-emitting section 20. As a result, the light-emitting efficiency of each light-emitting section 20 can be improved.

[0032] Moreover, from the viewpoint of further improving the luminous efficiency of each light-emitting section 20, it is preferable that the light-reflecting layer 31 be made of ceramic. When light from the light-emitting section 20 reaches the surface of the light-reflecting layer 31, light including evanescent light seeps into the light-reflecting layer 31. When the light-reflecting layer 31 is made of ceramic, the light-reflecting layer 31 can reduce absorption of light that seeps out from the light-emitting section 20 and increase light reflection compared to when it is made of metal or the like, thereby suppressing a decrease in the luminous efficiency of the light-emitting section 20.

[0033] The light-shielding layer 32 is disposed so that the light-reflecting layer 31 contacts two side surfaces intersecting the stacking direction. The light-shielding layer 32 is also disposed so as to be located between adjacent light-emitting sections 20 in the stacking direction. This makes it possible to suppress interference of light emitted from adjacent light-emitting sections 20. On both sides of each light-shielding layer 32, the light-reflecting layer 31 and the light-emitting section 20 are disposed in this order. The arrangement of the light-emitting sections 20, light-reflecting layer 31, and light-shielding layer 32 will be further described below.

[0034] In the illustrated example, one of the multiple light-emitting units 20 included in the wavelength conversion member 10 is referred to as the first light-emitting unit, and the light-emitting unit adjacent to the first light-emitting unit across the laminate 30 is referred to as the second light-emitting unit. Light incident on the first light-emitting unit includes a portion that travels toward the adjacent second light-emitting unit without being wavelength-converted by the phosphor. Most of this light is reflected by the light-reflecting layer 31 and returns to the first light-emitting unit. Some of the light incident on the first light-emitting unit and wavelength-converted by the phosphor travels toward the adjacent second light-emitting unit, but most of this light is reflected by the light-reflecting layer 31 and returns to the first light-emitting unit. Some of the light incident on the light-reflecting layer 31 from the first light-emitting unit may pass through the light-reflecting layer 31 and leak toward the second light-emitting unit. However, all or part of the light that leaks from the light-reflecting layer 31 toward the second light-emitting unit is absorbed by the light-shielding layer 32. This reduces the amount of light that reaches the second light-emitting unit compared to when the light-shielding layer 32 is not present. Similarly, much of the light that enters the second light-emitting section and travels toward the first light-emitting section after being wavelength-converted by the phosphor and / or light that travels toward the first light-emitting section without being wavelength-converted is reflected by the light-reflecting layer 31 and returns to the second light-emitting section. Some of the light that enters the light-reflecting layer 31 from the second light-emitting section may pass through the light-reflecting layer 31 and leak toward the first light-emitting section, but all or part of this light is absorbed by the light-shielding layer 32. This makes it possible to reduce the amount of light that reaches the first light-emitting section compared to when the light-shielding layer 32 is not present. In this way, interference between the light that enters the first light-emitting section and the light that enters the second light-emitting section can be suppressed.

[0035] As a result, for example, when light is incident on the first light-emitting section but not on the second light-emitting section, it is possible to suppress a portion of the light incident on the first light-emitting section from propagating to the second light-emitting section and causing the second light-emitting section to emit light. That is, it is possible to realize a wavelength conversion member 10 with an improved effect of suppressing the propagation of light from adjacent light-emitting sections 20. As a result, it is possible to cause each light-emitting section 20 to emit light independently without causing substantial optical interference between the adjacent light-emitting sections 20. Furthermore, because the effect of suppressing the propagation of light from adjacent light-emitting sections 20 can be obtained even when the laminate 30 is thin, it is possible to realize a wavelength conversion member 10 in which the propagation of light from adjacent light-emitting sections 20 is suppressed and the light-emitting sections 20 are arranged at a narrow pitch.

[0036] If the laminate 30 were composed only of the light-shielding layer 32, the light-shielding layer 32 would absorb much of the light that seeps out from the light-emitting units 20, including evanescent light, resulting in a decrease in the luminous efficiency of the light-emitting units 20. By forming the laminate 30 into a sandwich structure of a light-reflecting layer 31, a light-shielding layer 32, and another light-reflecting layer 31, as in the wavelength conversion member 10, most of the light that seeps out from the light-emitting units 20 can be reflected by the light-reflecting layer 31, and a portion of the light that is not reflected by the light-reflecting layer 31 and passes through the light-reflecting layer 31 can be absorbed by the light-shielding layer 32. This makes it possible to improve the luminous efficiency of the light-emitting units 20 while preventing light emitted by each light-emitting unit 20 from entering other light-emitting units 20.

[0037] Furthermore, for example, when laser light is incident on the light-emitting unit 20, the heat generated by the light-emitting unit 20 may be greater than when light from a light-emitting diode is incident on the light-emitting unit 20. By forming the light-reflecting layer 31 from ceramic, ceramic is less likely to deteriorate even at high temperatures caused by the heat generated by the light-emitting unit 20, and therefore the functions of the laminate 30 and the light-emitting unit 20 can be maintained.

[0038] (Method of manufacturing wavelength conversion member) The method for producing a wavelength conversion member according to the first embodiment includes a step of alternately laminating a laminate in which a green sheet having a reflective member, a green sheet having a light-shielding member, and a green sheet having a reflective member are laminated in this order with a ceramic sheet having a phosphor to produce a composite, and a step of pressurizing and firing the composite. The method for producing a wavelength conversion member according to the first embodiment may include other steps.

[0039] 2 to 6 are diagrams illustrating a method for manufacturing a wavelength conversion member according to the first embodiment. Here, a method for manufacturing the wavelength conversion member 10 shown in FIG. 1 will be described as an example of a method for manufacturing a wavelength conversion member according to the first embodiment, with reference to FIGS. 2 to 6 in order. Note that, for reference, mutually orthogonal X-axis, Y-axis, and Z-axis are shown in FIGS. 5 and 6. The directions parallel to the X-axis, Y-axis, and Z-axis are defined as the first direction X, the second direction Y, and the third direction Z, respectively.

[0040] First, as shown in FIG. 2, the required number of green sheets 31S having a reflective member, green sheets 32S having a light-shielding member, and ceramic sheets 20S having a phosphor are prepared. The green sheets 31S and 32S are obtained by preparing a slurry containing, for example, powder of the main material, a binder, a solvent, etc., and using a known method such as a doctor blade method. When using multiple green sheets 31S, it is preferable to adjust the slurry so that the densities of the green sheets 31S are equal. This makes it possible to make the shrinkage rates of the green sheets 31S equal before and after firing, thereby reducing the variation in the thickness of the light-reflecting layer 31 after firing. When using multiple green sheets 32S, it is preferable to adjust the slurry so that the densities of the green sheets 32S are equal. This makes it possible to make the shrinkage rates of the green sheets 32S equal before and after firing, thereby reducing the variation in the thickness of the light-shielding layer 32 after firing. Note that "equal density" here refers to the density (g / cm). 3) is within 10%. Examples of the main material of the green sheets 31S and 32S include aluminum oxide, yttrium oxide, titanium oxide, zirconium oxide, and silicon oxide. The green sheet 32S further includes a light absorber mixed into the main material. Examples of the light absorber to be mixed include ruthenium oxide, aluminum nitride, and silicon nitride.

[0041] The ceramic sheet 20S can be obtained by, for example, preparing a slurry containing phosphor powder, a binder, a solvent, etc., forming it into a phosphor green sheet using a known method such as the doctor blade method, and then firing the phosphor green sheet at a predetermined temperature. To achieve high density, the ceramic sheet 20S is preferably fired at a temperature higher than the firing temperature in the firing step described below. The ceramic sheet 20S is fabricated so that its thickness is the same as one side of the light-emitting portion 20 of the wavelength conversion member 10 to be finally fabricated. Phosphors contained in the ceramic sheet 20S include cerium-activated yttrium aluminum garnet (YAG), cerium-activated lutetium aluminum garnet (LAG), europium-activated silicate ((Sr,Ba)2SiO4), α-sialon phosphor, β-sialon phosphor, etc.

[0042] Each sheet is preferably rectangular, for example, of approximately the same size, when viewed from above with the largest surface facing upward. By making each sheet rectangular when viewed from above, when producing a rod-shaped wavelength conversion member 10, the wavelength conversion member 10 can be produced efficiently during the cutting process described below. Furthermore, the portion to be discarded after the cutting process can be reduced. Note that the shape of each sheet when viewed from above is not limited to this, and it may be a parallelogram, a circle, an ellipse, or another shape.

[0043] Next, as shown above the arrow in FIG. 3 , multiple laminates 30S are fabricated by stacking green sheets 31S, 32S, and 31S in this order. Furthermore, the thickness of the laminates 30S is adjusted by applying pressure or the like so that the pitch between the light-emitting sections 20 of the wavelength conversion member 10 to be fabricated later is the desired size. Considering the subsequent pressing and firing processes, the thickness of the laminates 30S is preferably 1.2 to 2 times the pitch between the light-emitting sections 20 of the wavelength conversion member 10. Then, as shown below the arrow in FIG. 3 , multiple laminates 30S and multiple ceramic sheets 20S are alternately stacked to fabricate a composite 100 (composite fabrication process). In the example of FIG. 3 , green sheets 31S are arranged below the ceramic sheet 20S arranged at the bottom and above the ceramic sheet 20S arranged at the top. The composite 100 may also be fabricated by stacking the sheets in order, starting from the bottom.

[0044] First, three green sheets 31S and 32S are stacked to form multiple laminates 30S, and then the multiple laminates 30S and multiple ceramic sheets 20S are alternately stacked to form the composite 100. This reduces uneven shrinkage of each laminate 30S during the pressurization process of the composite 100, as described below. Furthermore, compared to adjusting each green sheet 31S and green sheet 32S to a desired thickness and stacking them one by one with a ceramic sheet 20S, stacking three green sheets to form the laminate 30S to a desired thickness and then stacking them with the ceramic sheet 20S reduces the error in the thickness of the laminate 30S, which will later become the pitch between the light-emitting portions 20 of the wavelength conversion member 10, and reduces thickness variation between the individual laminates 30S. Note that in FIG. 3, instead of assigning reference numerals to all of the green sheets 31S and 32S, the green sheets 31S and 32S are indicated by dot patterns with different densities. This also applies to the following FIGS. 4 to 6.

[0045] Next, the composite 100 shown in FIG. 3 is pressed and fired to produce the composite 100A shown in FIG. 4. Specifically, first, the composite 100 shown in FIG. 3 is pressed from above and below (pressing step). Pressing of the composite 100 can be performed, for example, using a cold isostatic pressing device. In the pressing step, the composite 100 is preferably pressed under a pressure of 80 MPa or more. The composite 100 is more preferably pressed under a pressure of 100 MPa or more. This increases the density of the green sheets 31S and 32S, thereby reducing the shrinkage rate of the green sheets 31S and 32S during firing and preventing cracks from occurring in the green sheets 31S and 32S during firing. This also reduces the variation in the thickness of the green sheets 31S and 32S after firing. This also reduces the thickness of the green sheets 31S and 32S after firing, allowing the wavelength conversion member 10 to have a narrow pitch between the light-emitting portions 20.

[0046] Next, the composite 100 after pressing is fired to obtain a composite 100A (firing step). In the firing step, the firing temperature is, for example, 1300 to 1500°C. The composite 100 can be fired, for example, by a hot press or the like. In this case, it is preferable to perform firing while pressing the composite 100 from above and below. The pressure applied to the composite 100 in the firing step is lower than the pressure applied to the composite 100 in the pressing step. In the firing step, the pressure applied to the composite 100 is, for example, 10 MPa or less. The pressing step and the firing step may be performed simultaneously. That is, the composite 100 may be fired while being pressed, for example, to 100 MPa or more.

[0047] The shrinkage rate of the ceramic sheet 20S is smaller than that of the laminate 30 before and after the step of pressing and firing the composite 100. That is, because the ceramic sheet 20S is fired at a temperature higher than the firing temperature in the firing step prior to the composite fabrication step, it hardly shrinks in the stacking direction before and after the step of pressing and firing the composite 100. On the other hand, the green sheets 31S and 32S shrink in the stacking direction by approximately 20-30% in the pressing step and approximately 10% in the firing step. That is, in the composite 100A, the thickness of the ceramic sheet 20S is the same as that of the composite 100, but the thicknesses of the green sheets 31S and 32S are thinner than that of the composite 100. Thinner green sheets 31S and 32S allow for a narrower pitch between the ceramic sheets 20S. It is preferable that the lengths of the multiple laminates 30S in the stacking direction after firing are equal. This allows for a uniform pitch between the light-emitting sections 20 in the final wavelength conversion member 10. Here, "equal" means that a difference of ±10% is allowed.

[0048] Next, as shown in FIGS. 5 and 6, the composite 100A is cut to produce multiple wavelength conversion members 10. In the illustrated example, the stacking direction and the first direction X coincide. The composite 100A can be cut using, for example, a wire saw. First, as shown in FIG. 5, the composite 100A is cut along a plane parallel to a first plane formed by the first direction X and the second direction Y. The cut surface parallel to the first plane is parallel to the stacking direction (first direction X) of the composite 100A. In the example of FIG. 5, the composite 100A is cut in the stacking direction along multiple dashed-dotted lines CL1 parallel to the second direction Y to produce multiple composites 100B. In the example of FIG. 5, there are 14 dashed-dotted lines CL1, and 15 composites 100B are produced. The number of dashed-dotted lines CL1 is arbitrary and is not limited to the example of FIG. 5. Note that the parallel and perpendicular directions here allow for a difference of ±5 degrees or less. The same applies to the description of FIG. 6.

[0049] Here, in a composite or wavelength conversion member, a surface that is not perpendicular to a line parallel to the stacking direction (first direction X) is referred to as a stacking surface. More specifically, a stacking surface is a surface parallel to a line parallel to the stacking direction (first direction X) of the composite. The illustrated composite has four stacking surfaces. For example, in the composite 100B shown in FIG. 5, the four side surfaces parallel to the stacking direction (first direction X) are stacking surfaces, specifically, two side surfaces parallel to the XY plane and two side surfaces parallel to the XZ plane. In the illustrated example, the two side surfaces parallel to the YZ plane are not included in the stacking surfaces. In other words, a surface having only the side surface of one sheet or layer, for example, the side surface of the ceramic sheet 20S or the light-reflecting layer 31, is not referred to as a stacking surface. A surface having the side surfaces of two or more sheets or layers is referred to as a stacking surface. The stacking surfaces include surfaces that were part or all of the side surfaces of the composite 100A before cutting. Furthermore, the stacking surface includes the cut surface formed when the above-mentioned cutting is performed, and the cut surface parallel to the first plane and the cut surface parallel to the second plane described below are included in the stacking surface where multiple ceramic sheets 20S and laminate 30S are stacked.

[0050] After producing the composite 100B, a step of grinding the stacking surfaces of the composite 100B is performed. Specifically, two stacking surfaces parallel to the first plane (stacking surfaces parallel to the XY plane), including the cut surfaces formed in the cutting step described above, are ground. Grinding the two stacking surfaces of the composite 100B reduces variations in the thickness of each ceramic sheet 20S in the third direction Z. Furthermore, the thickness of each ceramic sheet 20S in the third direction Z can be adjusted to a desired thickness. Furthermore, a polishing step of polishing the two stacking surfaces described above can be provided. Polishing the two stacking surfaces can improve the surface accuracy of the two stacking surfaces of the composite 100B. For example, the polished stacking surfaces can be used as the upper or lower surfaces of the wavelength conversion member 10 that will be produced later by being singulated. All four stacking surfaces may be ground and polished, or the polishing step may not be provided.

[0051] Next, as shown in FIG. 6 , the composite 100B is cut along a plane parallel to a second plane formed by the first direction X and the third direction Z. The cut surface cut along the plane parallel to the second plane is parallel to the first direction X (stacking direction) of the composite 100B. The first and second planes are parallel to the first direction X (stacking direction). In other words, the cut surface formed during the cutting process is parallel to the stacking direction. The composites 100A and 100B are not cut along a plane perpendicular to the stacking direction. In the example of FIG. 6 , the composite 100B is cut vertically along multiple dashed-dotted lines CL2 parallel to the first direction X to produce multiple wavelength conversion members 10. In the example of FIG. 6 , there are three dashed-dotted lines CL, and four wavelength conversion members 10 are produced from one composite 100B. Because 15 composites 100B are produced in the process of FIG. 5 , a total of 60 wavelength conversion members 10 are produced in this process. The number of dashed dotted lines CL2 is arbitrary and is not limited to the example in Fig. 6. In the fabricated wavelength conversion member 10, a layer formed by firing green sheet 31S having a reflective member and a layer formed by firing green sheet 32S having a light-shielding member are made of ceramic, and the light-shielding member includes a light absorber.

[0052] The first plane and the second plane intersect. Preferably, the first plane and the second plane are perpendicular to each other. In this case, the cut surface formed when cutting along a plane parallel to the first plane is perpendicular to the cut surface formed when cutting along a plane parallel to the second plane. By making the cutting planes perpendicular to each other, for example, when making the composite 100 by stacking rectangular sheets, a rod-shaped wavelength conversion member 10 can be efficiently produced. In this case, the upper, lower, and side surfaces of the wavelength conversion member 10 are rectangular. Note that the angle at which the two cut planes intersect is not limited to a right angle. By cutting along two planes, multiple wavelength conversion members 10 of a desired shape can be produced regardless of the shape of the composite 100. Note that if multiple wavelength conversion members 10 of a desired shape can be produced by cutting along only one plane, cutting along two planes is not necessary. Examples of such cases include when one side of the wavelength conversion member is extremely short or when only a few wavelength conversion members are to be produced.

[0053] The composite production process is not limited to a process of alternately stacking a plurality of laminates 30S and a plurality of ceramic sheets 20S as shown in FIG. 3. The composite production process may be, for example, a process of stacking one laminate 30S and one ceramic sheet 20S to produce a composite 100C as shown in FIG. 7. Alternatively, the composite production process may be a process of stacking ceramic sheets 20S on both sides of one laminate 30S to produce a composite 100D as shown in FIG. 7 or 8. The method for producing a wavelength conversion member according to the present invention is also effective when producing the composites shown in FIG. 7 or 8.

[0054] In this specification, "the step of alternately stacking ceramic sheets 20S and laminates 30S" includes the step of producing the composite shown in Figures 7 and 8. Also, "the step of alternately stacking a plurality of ceramic sheets 20S and laminates 30S" does not include the step of producing the composite shown in Figure 7, but includes the step of producing the composite shown in Figure 8. "The step of alternately stacking a plurality of ceramic sheets 20S and a plurality of laminates 30S" does not include the step of producing the composite shown in Figures 7 and 8.

[0055] As described above, the method for manufacturing a wavelength conversion member 10 according to the first embodiment can realize a method for manufacturing a wavelength conversion member 10 that improves the effect of suppressing the propagation of light from adjacent light-emitting portions 20. Furthermore, in the method for manufacturing a wavelength conversion member 10 according to the first embodiment, the pitch of the light-emitting portions 20 is determined by the thickness of the light-reflecting layer 31 produced by firing the green sheet 31S and the light-shielding layer 32 produced by firing the green sheet 32S. Furthermore, by adjusting the density of the green sheets 31S and 32S, errors caused by shrinkage of the green sheets 31S and 32S during the firing process can be reduced. Therefore, by setting the green sheets 31S and 32S to a predetermined thickness, the pitch of the light-emitting portions 20 in the resulting wavelength conversion member 10 can be made substantially constant. In other words, a wavelength conversion member 10 can be manufactured in which multiple light-emitting portions 20 are arranged with high positional accuracy.

[0056] (Modification of wavelength conversion member) FIG. 9 is a perspective view of a wavelength conversion member according to Modification 1 of the first embodiment. In the wavelength conversion member 10 shown in FIG. 1, light reflecting layers 31 are arranged on both ends in the stacking direction (first direction X). However, as in wavelength conversion member 10A shown in FIG. 9, light reflecting layers 31 do not have to be arranged on both ends in the stacking direction. In wavelength conversion member 10A, both ends in the stacking direction are light emitting sections 20. In other words, the two side surfaces of wavelength conversion member 10A perpendicular to the stacking direction (first direction X) become side surfaces of the light emitting sections 20. Even if light reflecting layers 31 are not arranged on both ends in the stacking direction as in wavelength conversion member 10A, when different light beams are incident on adjacent light emitting sections 20, the effect of suppressing interference between the respective light beams can be obtained.

[0057] The wavelength conversion member 10A can be produced by producing a composite in the process shown in FIG. 3 without placing a green sheet 31S under the ceramic sheet 20S that is located at the bottom among the plurality of ceramic sheets 20S and on the ceramic sheet 20S that is located at the top, and then by carrying out the same processes as those shown in FIGS. 4 to 6.

[0058] FIG. 10 is a perspective view of a wavelength conversion member according to Modification 2 of the first embodiment. As in wavelength conversion member 10B shown in FIG. 10, a light reflecting layer 31 and a light blocking layer 32 may be sequentially arranged on both ends in the stacking direction, starting from the side closer to the light-emitting section 20. In a plan view seen from the stacking direction, the side surface of the light blocking layer 32 becomes the side surface of wavelength conversion member 10B. The light reflecting layer 31 is arranged so as to contact the side surface opposite to the side surface of light blocking layer 32 that becomes the side surface of wavelength conversion member 10B. FIG. 11 is a perspective view of a wavelength conversion member according to Modification 3 of the first embodiment. As in wavelength conversion member 10C shown in FIG. 11, both ends in the stacking direction may be laminated bodies 30. In a plan view seen from the stacking direction, the side surface of the light reflecting layer 31 becomes the side surface of wavelength conversion member 10C. Furthermore, the light blocking layer 32, the light reflecting layer 31, and the light-emitting section 20 are arranged in this order so as to contact the side surface of the light reflecting layer 31 that becomes the side surface of wavelength conversion member 10C. As in the wavelength conversion members 10, 10B, and 10C, when a light reflecting layer 31, a laminate of a light reflecting layer 31 and a light-shielding layer 32, or a laminate 30 is disposed at both ends in the stacking direction, this is preferable because the amount of light seeping out from the light-emitting units 20 in the stacking direction can be made uniform or close to uniform between the two light-emitting units 20 closest to both ends in the stacking direction and the other light-emitting units 20. This makes it possible to reduce uneven color and brightness between the light-emitting units 20.

[0059] Wavelength conversion member 10B can be produced by preparing a composite by arranging green sheet 32S below the lowest green sheet 31S and above the highest green sheet 31S in the process shown in Fig. 3, and then performing the same processes as those shown in Figs. 4 to 6. Wavelength conversion member 10C can be produced by preparing a composite by arranging laminate 30 instead of green sheet 31S below the ceramic sheet 20S arranged at the bottom and above the ceramic sheet 20S arranged at the top in the process shown in Fig. 3, and then performing the same processes as those shown in Figs. 4 to 6.

[0060] Second Embodiment FIG. 12 is a perspective view of a wavelength conversion member according to a second embodiment. For reference, FIG. 12 shows mutually orthogonal X, Y, and Z axes. The directions parallel to the X, Y, and Z axes are the first direction X, the second direction Y, and the third direction Z, respectively. A wavelength conversion member according to this embodiment, like wavelength conversion member 10D shown in FIG. 12, further includes a light reflecting portion 40 in addition to the wavelength conversion member 10 according to the first embodiment. In the following description, to distinguish between wavelength conversion member 10D and wavelength conversion member 10, wavelength conversion member 10 will be referred to as laminated portion 15. Note that wavelength conversion member 10D may include any of wavelength conversion members 10A, 10B, and 10C as laminated portion 15 instead of wavelength conversion member 10.

[0061] The light reflecting unit 40 is, for example, a frame-shaped member having a rectangular opening. The light reflecting unit 40 has an upper surface, a lower surface opposite the upper surface, one or more inner surfaces connecting the inner edges of the upper surface and the lower surface, and one or more outer surfaces connecting the outer edges of the upper surface and the lower surface. The outer and inner edges of the upper surface and the outer and inner edges of the lower surface are, for example, rectangular. In this case, the light reflecting unit 40 has four rectangular inner surfaces and four rectangular outer surfaces. Note that the outer and inner edges of the upper surface and the outer and inner edges of the lower surface are not limited to rectangular and can be any shape, such as circular, elliptical, or polygonal.

[0062] The light reflecting portion 40 is, for example, a sintered body formed with ceramic as the main material. Examples of ceramics used as the main material include aluminum oxide, aluminum nitride, silicon oxide, yttrium oxide, zirconium oxide, and magnesium oxide. Among these, aluminum oxide is preferred because of its high reflectivity. Furthermore, aluminum oxide is a preferred main material because it has relatively high thermal conductivity among these ceramics. However, the light reflecting portion 40 does not have to be made primarily of ceramic.

[0063] In the wavelength conversion member 10D, in top view, the light reflecting portion 40 surrounds two stacking surfaces of the stacked portion 15 and two side surfaces perpendicular to the stacking direction. In other words, the inner surface of the light reflecting portion 40 is connected to two of the four stacking surfaces of the stacked portion 15. The other two stacking surfaces are not connected to the inner surface of the light reflecting portion 40. In detail, the light reflecting portion 40 connects to two side surfaces of each light emitting portion 20, two side surfaces of each stacked body 30, and two side surfaces in the stacking direction of the wavelength conversion member 10, i.e., surfaces perpendicular to the stacking direction of the two light reflecting layers 31 located at both ends. The wavelength conversion member 10D has a flat plate shape, for example, a rectangular parallelepiped.

[0064] The two stacking surfaces of the stacking unit 15 that are not connected to the inner surface of the light reflecting unit 40 can become part of the upper and lower surfaces of the wavelength conversion member 10D. In this case, the upper surface of the stacking unit 15 and the upper surface of the light reflecting unit 40 form, for example, a single continuous plane. Furthermore, the lower surface of the stacking unit 15 and the lower surface of the light reflecting unit 40 form, for example, a single continuous plane. Note that the upper surface and / or the lower surface of the stacking unit 15 may have a shape that protrudes further than the upper surface and / or the lower surface of the light reflecting unit 40. In this case, part of the four side surfaces of the stacking unit 15 are exposed from the inner surface of the light reflecting unit 40.

[0065] Wavelength conversion member 10D can be manufactured by, for example, slip casting. Specifically, the method for manufacturing wavelength conversion member 10D includes the steps of arranging a member containing a ceramic material around composite 100B (in this case, laminated section 15 having the same structure as wavelength conversion member 10) cut in the step shown in FIG. 6 and forming light reflecting section 40 that connects the two laminated surfaces of cut composite 100B. The step of forming light reflecting section 40 also includes the steps of arranging a liquid member containing a ceramic material around the two laminated surfaces of cut composite 100B and firing the liquid. In this specification, ceramic refers to the material after firing, and ceramic material refers to the material before firing.

[0066] By disposing a liquid member containing a ceramic material around the laminated portion 15 and firing it, the light reflecting portion 40 formed can be made to contain many voids near the boundary with the laminated portion 15, increasing the porosity, and conversely, the porosity near the outer edge, far from the laminated portion 15, can be made lower than near the boundary. By increasing the porosity near the boundary of the light reflecting portion 40, the light reflectance near the boundary with the laminated portion 15 can be increased. Furthermore, by reducing the porosity near the outer edge of the light reflecting portion 40, the density near the outer edge can be increased, ensuring the strength of the entire wavelength conversion member 10D.

[0067] The density of the light reflecting portion 40 near the boundary with the laminated portion 15 is preferably even lower than the density of the light reflecting layer 31 formed by firing the green sheet 31S having a reflective member. As described above, by increasing the porosity of the light reflecting portion 40 near the boundary with the laminated portion 15, a larger reflective area of ​​air is formed at the boundary between the side surface of each light emitting portion 20 and the inner surface of the light reflecting portion 40, thereby improving the effect of reflecting light that strikes the inner surface of the light reflecting portion 40 from each light emitting portion 20 toward each light emitting portion 20. This structure can improve the light extraction efficiency of the wavelength conversion member 10D. The porosity can be adjusted by the sintering conditions (sintering temperature, sintering time, heating rate), the type and particle size of the material, the concentration of the sintering aid, etc.

[0068] For example, in the wavelength conversion member 10D shown in FIG. 12, when a vertical cross section cut in the stacking direction (first direction X) so as to pass through a straight line connecting the midpoints of the two sides extending in the second direction Y on the upper surface of the laminated portion 15 is observed with an SEM (scanning electron microscope), if the proportion (e.g., area ratio) of voids contained in the light reflecting portion 40 is higher than the proportion of voids contained in the light reflecting layer 31, it can be determined that the light reflecting portion 40 has a lower density than the light reflecting layer 31.

[0069] Third Embodiment In the third embodiment, an example of a light emitting device using the wavelength conversion member of the second embodiment is shown. Fig. 13 is a top view of the light emitting device of the third embodiment. Fig. 14 is a cross-sectional view of the light emitting device taken along the XIV-XIV section line in Fig. 13. Fig. 15 is a top view of the light emitting device of the third embodiment from which the wavelength conversion member, the light-transmitting member, and the light-blocking member have been removed. In Figs. 13 to 15, mutually orthogonal X-, Y-, and Z-axes are shown for reference. The directions parallel to the X-, Y-, and Z-axes are defined as the first direction X, the second direction Y, and the third direction Z, respectively.

[0070] The light emitting device of the third embodiment has a plurality of light emitting elements and a wavelength conversion member, and light emitted from each of the plurality of light emitting elements is incident on a different light emitting section of the wavelength conversion member, and each light emitting section converts the incident light into light of a different wavelength.

[0071] The illustrated light emitting device 200 is an example of a light emitting device according to Embodiment 3. The light emitting device 200 includes a wavelength converting member 10D, a package 210, a plurality of light emitting elements 220, one or more submounts 230, one or more light reflecting members 240, a light-transmitting member 280, and a light-shielding member 290.

[0072] The following describes each component of the light emitting device 200. The description of the wavelength conversion member 10D will be omitted.

[0073] (Package 210) The package 210 has a base 211 and a frame 212 that surrounds the base 211 and extends upward. The frame 212 has a stepped portion 213 on its inner side. The base 211 has an upper surface 211a and a lower surface. The frame 212 has an upper surface 212a, one or more inner surfaces 212c, and one or more outer surfaces 212d. The stepped portion 213 is provided on the inner side of the frame 212 and has an upper surface 213a that connects to the inner surface 212c of the frame. The upper surface 213a of the stepped portion 213 is located higher than the upper surface 211a of the base and lower than the upper surface 212a of the frame. A plurality of electrodes are provided on the upper surface 212a of the frame 212 shown in the figure.

[0074] The package 210 can be formed, for example, primarily from ceramic. For example, aluminum nitride, silicon nitride, aluminum oxide, or silicon carbide can be used as the ceramic. Note that the package 210 is not limited to ceramic, and may be formed primarily from other materials, such as metal.

[0075] (light-emitting element 220) The light emitting element 220 is, for example, a semiconductor laser element. The light emitting element 220 is not limited to a semiconductor laser element, and may be, for example, a light emitting diode (LED) or an organic light emitting diode (OLED).

[0076] The light emitting element 220 has, for example, a rectangular outer shape when viewed from above. A side surface intersecting one of the two short sides of the rectangle serves as an emission surface for light emitted from the light emitting element 220. The upper and lower surfaces of the light emitting element 220 have areas larger than the emission surface.

[0077] Here, a case where the light emitting element 220 is a semiconductor laser element will be described. Note that the light (laser light) emitted from the light emitting element 220 has a spread and forms an elliptical far-field pattern (hereinafter referred to as "FFP") on a plane parallel to the emission surface. Here, FFP refers to the shape and light intensity distribution of the emitted light at a position away from the emission surface.

[0078] The direction passing through the major axis of the ellipse is defined as the fast axis direction of the FFP, and the direction passing through the minor axis of the ellipse is defined as the slow axis direction of the FFP, based on the elliptical light emitted from the light emitting element 220. The fast axis direction of the FFP in the light emitting element 220 can coincide with the stacking direction in which multiple semiconductor layers including the active layer of the light emitting element 220 are stacked.

[0079] Furthermore, based on the light intensity distribution of the FFP of the light emitting element 220, 1 / e 2 The light having an intensity of 1 / e or more is called the main part of the light. 2The angle corresponding to the intensity of the FFP is called the divergence angle. The divergence angle in the fast axis direction of the FFP is larger than the divergence angle in the slow axis direction of the FFP.

[0080] Furthermore, the light passing through the center of the elliptical shape of the FFP, in other words, the light with the peak intensity in the light intensity distribution of the FFP, is referred to as the light traveling along the optical axis or the light passing through the optical axis. Also, the optical path of the light traveling along the optical axis is referred to as the optical axis of that light.

[0081] As the light emitting element 220, for example, a semiconductor laser element that emits blue light can be used.

[0082] Here, blue light refers to light whose emission peak wavelength is in the range of 420 nm to 494 nm. For example, when using a semiconductor laser element in combination with a YAG phosphor, it is preferable to use a semiconductor laser element that emits light whose peak wavelength is 480 nm or less, taking into account the excitation efficiency.

[0083] Examples of semiconductor laser elements that emit blue light include semiconductor laser elements that include nitride semiconductors. Examples of nitride semiconductors that can be used include GaN, InGaN, and AlGaN. Note that semiconductor laser elements that emit light other than blue may also be used as the light-emitting element 220.

[0084] (Submount 230) The submount 230 is, for example, in the shape of a rectangular parallelepiped and has a bottom surface, a top surface, and multiple side surfaces. The shape of the submount 230 is not limited to a rectangular parallelepiped. The submount 230 is formed using, for example, aluminum nitride or silicon carbide, but other materials may also be used. Furthermore, a metal film, for example, is provided on the top surface of the submount 230.

[0085] (Light reflecting member 240) The light reflecting member 240 has a light reflecting surface that reflects light. The light reflecting surface is, for example, a surface that has a light reflectance of 90% or more for the peak wavelength of the irradiated light. The light reflectance here may be 100% or less. The light reflecting surface is inclined with respect to the lower surface. The inclination angle of the light reflecting surface with respect to the lower surface is, for example, 45 degrees.

[0086] It is preferable to select a heat-resistant material as the main material for the light reflecting member 240, and examples of such materials include glass such as quartz or BK7 (borosilicate glass), metal such as aluminum, or Si. The light reflecting surface can be formed using a metal such as Ag or Al, or a dielectric multilayer film of Ta2O5 / SiO2, TiO2 / SiO2, or Nb2O5 / SiO2. Note that A / B indicates a multilayer film in which a film of A and a film of B are stacked in order.

[0087] (Translucent member 280) The light-transmitting member 280 is a light-transmitting member. Here, light-transmitting means that the transmittance for the peak wavelength of incident light is 80% or more. The light-transmitting member 280 has an upper surface, a lower surface opposite the upper surface, and side surfaces that intersect with the upper and lower surfaces. The side surfaces connect the outer edges of the upper surface and the lower surface. The light-transmitting member 280 is, for example, a rectangular parallelepiped or a cube. In this case, both the upper surface and the lower surface of the light-transmitting member 280 are rectangular, and the light-transmitting member 280 has four rectangular side surfaces.

[0088] The light-transmitting member 280 is not limited to a rectangular parallelepiped or a cube. That is, when viewed from above, the light-transmitting member 280 is not limited to a rectangle, and can have any shape, such as a circle, an ellipse, or a polygon.

[0089] The light-transmitting member 280 has a base material configured in the shape of a flat plate, such as a rectangular parallelepiped. The base material of the light-transmitting member 280 can be formed, for example, using sapphire as the main material. Sapphire is a material with relatively high transmittance and relatively high strength. Note that, in addition to sapphire, the main material may be a light-transmitting material including, for example, quartz, silicon carbide, or glass.

[0090] (Light blocking member 290) The light blocking member 290 can be formed, for example, from a resin having light blocking properties. Here, light blocking properties refer to the property of not transmitting light, and light blocking properties may be achieved by utilizing properties such as light absorption or reflection in addition to the light blocking property. The light blocking member 290 can be formed, for example, by incorporating fillers such as a light diffusing material and / or a light absorbing material into a resin.

[0091] Examples of the resin that forms the light-shielding member 290 include epoxy resin, silicone resin, acrylate resin, urethane resin, phenol resin, and BT resin. Examples of the light-absorbing filler contained in the light-shielding member 290 include dark-colored pigments such as carbon black.

[0092] (Light emitting device 200) In the illustrated example of the light emitting device 200, the wavelength conversion member 10D is bonded to the upper surface of the light-transmitting member 280. For example, the wavelength conversion member 10D is smaller than the light-transmitting member 280 in a top view. The upper surface of the light-transmitting member 280 is bonded to the lower surface of the wavelength conversion member 10D. In a top view, each light-emitting unit 20 of the wavelength conversion member 10D is located inside the outer edge shape of the upper surface of the light-transmitting member 280.

[0093] The outer periphery of the lower surface of the light-transmitting member 280 is joined to, for example, the upper surface 213a of the step portion 213 provided inside the frame portion 212 of the package 210. By joining the light-transmitting member 280 to the package 210, a closed space in which the light-emitting element 220 is arranged is formed. In this way, in the light-emitting device 200, the light-transmitting member 280 can serve as a lid member. Furthermore, this closed space is formed in an airtight sealed state. By being airtightly sealed, it is possible to prevent organic matter and the like from collecting on the light-emitting surface of the light-emitting element 220.

[0094] In the illustrated example of the light emitting device 200, five light reflecting members 240 are arranged on the upper surface 211a of the base 211. The five light reflecting members 240 are arranged, for example, on the same metal film, and the lower surface of the metal film is joined to the upper surface 211a of the base 211. The five light reflecting members 240 may be arranged on different metal films. The five light reflecting members 240 are arranged, for example, at predetermined intervals in the X direction when viewed from above.

[0095] In the illustrated example of the light emitting device 200, one submount 230 is disposed on the upper surface 211a of the base 211. The submount 230 is disposed on a metal film, and the lower surface of the metal film is bonded to the upper surface 211a of the base 211. The submount 230 has, for example, a rectangular shape when viewed from above, and is disposed with the long side of the rectangle facing the X direction. The submount 230 is also disposed on the metal film on which the light reflecting member 240 is disposed. Note that the submount 230 and the light reflecting member 240 may be disposed on different metal films. Multiple submounts 230 may be disposed on the metal film.

[0096] Each light-emitting element 220 is disposed on the upper surface 211a of the base 211. Specifically, each light-emitting element 220 is disposed on the upper surface of a submount 230. In the illustrated example of the light-emitting device 200, five light-emitting elements 220 are disposed on the upper surface of the same submount 230, and the lower surface of the submount 230 is joined to the upper surface 211a of the base 211. The five light-emitting elements 220 are, for example, rectangular in top view, and are disposed at predetermined intervals in the X direction with the long sides of the rectangle facing the Y direction. In top view, the light-emitting surface of each light-emitting element 220 is parallel to or perpendicular to the inner surface 212c or the outer surface 212d of the frame 212. Each light-emitting element 220 is disposed with its light-emitting surface facing the same direction. Each light-emitting element 220 may be disposed on the upper surface of a different submount 230.

[0097] Each light reflecting member 240 has a light reflecting surface that is inclined toward the corresponding light emitting element 220. Light emitted from the emission surface of each light emitting element 220 is irradiated onto the light reflecting surface of the corresponding light reflecting member 240. The corresponding light reflecting member 240 is a light reflecting member 240 that has a surface that faces the emission surface of each light emitting element 220 in a top view. The light emitting elements 220 are arranged so that at least a major portion of the light is irradiated onto the light reflecting surface.

[0098] A major portion of the light emitted by each light-emitting element 220 is reflected by the light-reflecting surface of the corresponding light-reflecting member 240 and enters the light-transmitting member 280. A major portion of the light reflected by the light-reflecting surface of each light-reflecting member 240 passes through the light-transmitting member 280 and then enters each light-emitting section 20. A part or all of the light that enters each light-emitting section 20 is converted into light of a different wavelength by each light-emitting section 20. The light that enters each light-emitting section 20 or the light whose wavelength has been converted by each light-emitting section 20 is emitted to the outside of the light-emitting device 200 from the top surface of each light-emitting section 20. In the light-emitting device 200, each light-emitting element 220 can be driven independently.

[0099] The light blocking member 290 is formed above the light-transmitting member 280. The light blocking member 290 is formed so as to fill the gap between the frame portion 212 of the package 210 and the wavelength conversion member 10. The light blocking member 290 can be formed, for example, by pouring a thermosetting resin and hardening it with heat. Providing the light blocking member 290 suppresses light leakage.

[0100] The light blocking member 290 does not reach the upper surface of the wavelength conversion member 10D. Alternatively, even if the light blocking member 290 reaches the upper surface of the light reflecting portion 40 of the wavelength conversion member 10D, it does not reach the upper surface of the light emitting portion 20.

[0101] In the light emitting device 200, the plurality of light emitting sections 20 are arranged with high positional accuracy in the wavelength conversion member 10D, so that a major portion of the light reflected by the light reflecting surface of each light reflecting member 240 can be reliably incident on the corresponding light emitting section 20. Furthermore, in the light emitting device 200, the laminate 30 can suppress the propagation of light from adjacent light emitting sections 20, so that light can be incident independently on each light emitting section 20 without causing substantial optical interference between adjacent light emitting sections 20, and light that has been wavelength converted by the light emitting sections 20 can be emitted.

[0102] The light emitting device 200 can be used, for example, in an in-vehicle headlight, but is not limited to this, and can also be used as a light source for lighting, a projector, a head-mounted display, a backlight for other displays, and the like.

[0103] Although the preferred embodiments have been described in detail above, the present invention is not limited to the above-described embodiments, and various modifications and substitutions can be made to the above-described embodiments without departing from the scope of the claims. [Explanation of symbols]

[0104] 10, 10A, 10B, 10C, 10D Wavelength conversion material 15 Lamination section 20 Light-emitting part 20S ceramic sheet 30,30S laminate 31 Light reflective layer 31S, 32S Green Sheet 32 Light blocking layer 40 Light reflection part 100,100A,100B,100C,100D complex 200 Light-emitting device 210 packages 211 Base 211a Top side 212 Frame 212a Top 212c inner surface 212d External surface 213 Step 213a Top side 220 Light-emitting element 230 Submount 240 Light-reflecting member 280 Translucent material 290 Light-shielding material

Claims

1. a step of alternately laminating a laminate in which a green sheet having a reflective member, a green sheet having a light-shielding member, and a green sheet having a reflective member are laminated in this order with a ceramic sheet having a phosphor to produce a composite; pressing and sintering the composite; A method for manufacturing a wavelength conversion member, comprising:

2. 2. The method for manufacturing a wavelength conversion member according to claim 1, further comprising a step of cutting the pressed and fired composite, the step including a step of cutting the composite along a plane parallel to a first plane, and a step of cutting along a plane parallel to a second plane intersecting the first plane.

3. The method for manufacturing a wavelength conversion member according to claim 2 , wherein in the step of cutting the composite, the first plane and the second plane are planes parallel to a stacking direction of the composite.

4. 4. The method for manufacturing a wavelength conversion member according to claim 2 or 3, further comprising the step of arranging a member containing a ceramic material around the periphery of the cut composite and forming a light reflecting portion connecting two stacking surfaces of the cut composite.

5. 5. The method for manufacturing a wavelength conversion member according to claim 4, wherein the step of forming the light reflecting portion includes the step of disposing the liquid member containing the ceramic material around the stacking surface and firing the liquid member.

6. The method for manufacturing a wavelength conversion member according to claim 4 or 5, wherein the light reflecting portion has a density lower than that of a layer formed by firing a green sheet having the reflecting member.

7. the layer formed by firing the green sheet having the reflective member and the layer formed by firing the green sheet having the light-shielding member are made of ceramic, The method for manufacturing a wavelength conversion member according to claim 1 , wherein the light blocking member includes a light absorbing material.

8. In the step of preparing the composite, the composite is prepared by alternately stacking a plurality of the laminates and a plurality of ceramic sheets having the phosphor; The method for manufacturing a wavelength conversion member according to claim 1 , wherein the plurality of laminates after firing have the same length in the stacking direction.

9. 9. The method for manufacturing a wavelength conversion member according to claim 1, wherein a shrinkage rate of the ceramic sheet having the phosphor before and after the step of pressing and firing the composite is smaller than a shrinkage rate of the laminate.

10. a plurality of light-emitting units made primarily of ceramic containing a phosphor; a plurality of laminates in which a light-reflecting layer, a light-blocking layer, and a light-reflecting layer are laminated in this order; A wavelength conversion member in which the laminate and the light emitting portion are alternately arranged in a stacking direction of the laminate.

11. The wavelength conversion member according to claim 10 , wherein the light reflecting layer and the light blocking layer are made mainly of ceramic.

12. The light-reflecting layer has light reflectivity, The wavelength conversion member according to claim 10 , wherein the light-shielding layer includes a light absorber.

13. The wavelength conversion member according to claim 10 , wherein the laminates have the same length in the stacking direction.

14. Further, a light reflecting portion is provided, The wavelength conversion member according to claim 10 , wherein the light reflecting portion is connected to two side surfaces of the light emitting portion.

15. The wavelength conversion member according to claim 14 , wherein the light reflecting portion is made primarily of ceramic and has a lower density than the light reflecting layer.

16. 16. The wavelength conversion member according to claim 10, wherein the length of the light emitting portion is 0.3 mm or more and 1.5 mm or less in the stacking direction of the laminate, and the length of the laminate is 0.1 mm or more and 1.5 mm or less.

17. The wavelength conversion member according to claim 16 , wherein the length of the light emitting portion is longer than the length of the laminate in the stacking direction of the laminate.

18. a plurality of semiconductor laser elements; The wavelength conversion member according to any one of claims 10 to 17, The light beams emitted from the plurality of semiconductor laser elements are incident on different light-emitting portions, A light-emitting device in which each of the light-emitting portions converts the incident light into light of a different wavelength.

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