JP7028863B2 - Wavelength conversion element, light emitting device and lighting device - Google Patents

Description

The present disclosure relates to a wavelength conversion element, and a light emitting device and a lighting device including the wavelength conversion element.

Conventionally, a light emitting device using an excitation light source and a wavelength conversion element has been proposed (see, for example, Patent Document 1). As this type of light emitting device, the light emitting device disclosed in Patent Document 1 will be described with reference to FIG. 25. FIG. 25 is a schematic view of a conventional light emitting device.

The light emitting device 1063 disclosed in Patent Document 1 includes an excitation light source 1070, an excitation light condensing lens 1139, a wavelength conversion element (fluorescent wheel 1071) to which a phosphor layer 1131 is attached, and a light guide device 1075. It is composed.

In the phosphor wheel 1071, the phosphor layer 1131 is attached to the substrate 1130 via the reflective layer 1138. The base material 1130 is formed of a heat transfer member such as a copper plate, and a reflective layer 1138 composed of silver vapor deposition or the like is provided on the heat transfer member. The reflective layer 1138 reflects the excitation light and the light generated by the phosphor.

The excitation light emitted from the excitation light source 1070 is focused by the excitation light condensing lens and irradiates the phosphor layer 1131. Then, the excitation light is absorbed by the phosphor in the phosphor layer 1131. Along with this, the phosphor emits fluorescence. This fluorescence is guided to the light guide device 1075.

At this time, it has been proposed to use a heat transfer member such as a copper plate as the base material 1130 to disperse the heat generated in the layer of the phosphor to the entire heat transfer member and effectively dissipate heat.

Japanese Unexamined Patent Publication No. 2010-85740

In the light emitting device 1063 that obtains emitted light by irradiating the layer of the phosphor with the excitation light disclosed in Patent Document 1, in order to emit the emitted light with higher brightness, the wavelength conversion element is irradiated with light having a high light density. In this case, the temperature rises locally in the region irradiated with the excitation light of the phosphor layer 1131. Such an increase in the temperature of the layer of the phosphor causes a sharp decrease in the conversion efficiency of the phosphor and damage to the wavelength conversion element.

Therefore, it is an object of the present disclosure to provide a wavelength conversion element capable of sufficiently converting excitation light into fluorescence and having enhanced mechanical intensity, and a light emitting device and a lighting device provided with the wavelength conversion element.

In order to solve the above problems, one aspect of the wavelength conversion element according to the present disclosure includes a support member having a support surface and a wavelength conversion member arranged above the support surface, and the wavelength conversion member includes the support member. It has a radial surface located on the opposite side of the support surface, the radial surface including a peripheral region including a peripheral edge of the radial surface and a central region surrounded by the peripheral region, and at least a part of the peripheral region. Has a first apex that protrudes from the central region in a direction away from the support surface, and the radial surface is inclined toward the support surface side from the first apex toward the central region. It has an inclined portion.

As described above, in the wavelength conversion element in which the wavelength conversion member is fixed on the support member, the linear expansion coefficients of the support member and the wavelength conversion member may be different. In such a case, the thicker the film thickness of the wavelength conversion member, the more the stress applied to the wavelength conversion member due to the temperature change of the wavelength conversion element is relaxed, and the wavelength conversion member can be prevented from peeling off from the support member. ..

On the other hand, the thinner the film thickness of the wavelength conversion member, the more the temperature rise of the wavelength conversion member can be suppressed. Therefore, in the wavelength conversion element of the present disclosure, if the excitation light is irradiated to the central region where the film thickness of the wavelength conversion member is thin, the excitation light can be sufficiently converted into fluorescence by suppressing the temperature rise of the wavelength conversion member.

In addition, by providing a peripheral portion with a thick film thickness of the wavelength conversion member around the central region, the wavelength conversion member is supported against changes in the environmental temperature of the wavelength conversion element and temperature changes when the wavelength conversion element is made to emit light. It is possible to suppress peeling from the member. That is, in the wavelength conversion element according to the present embodiment, the mechanical strength can be increased.

Further, in one aspect of the wavelength conversion element according to the present disclosure, the central region may include a flat portion having a gentler inclination than the first inclined portion.

Further, in one aspect of the wavelength conversion element according to the present disclosure, a plurality of minute convex portions may be formed on the radial surface of the first inclined portion.

Further, in one aspect of the wavelength conversion element according to the present disclosure, the arrangement region on the support surface on which the wavelength conversion member is arranged may be a flat surface.

Further, in one aspect of the wavelength conversion element according to the present disclosure, the film thickness at the first top portion of the wavelength conversion member may be thicker than the film thickness at the central region.

Further, in one aspect of the wavelength conversion element according to the present disclosure, the film thickness of the wavelength conversion member in the central region may be 15 μm or more and 35 μm or less.

Further, in one aspect of the wavelength conversion element according to the present disclosure, the wavelength conversion member may include a plurality of first phosphor particles made of the same material in the central region and the first top portion.

Further, in one aspect of the wavelength conversion element according to the present disclosure, the wavelength conversion member may include a transparent binder that binds the plurality of first phosphor particles.

Further, in one aspect of the wavelength conversion element according to the present disclosure, the wavelength conversion member may include a plurality of scattered particles bonded to the transparent coupling material.

Further, in one aspect of the wavelength conversion element according to the present disclosure, the total volume of the plurality of first phosphor particles may be 35% or more and 62% or less with respect to the volume of the wavelength conversion member.

Further, in one aspect of the wavelength conversion element according to the present disclosure, in the cross section of the wavelength conversion member, the total cross-sectional area of the plurality of first phosphor particles is 40% or more with respect to the cross-sectional area of the wavelength conversion member. It may be 80% or less.

Further, in one aspect of the wavelength conversion element according to the present disclosure, a plurality of minute convex portions are formed on the radial surface of the first inclined portion, and at least a part of the plurality of minute convex portions is described above. A part of the plurality of first phosphor particles may be formed by projecting on the radiation surface.

Further, in one aspect of the wavelength conversion element according to the present disclosure, the wavelength conversion member includes a second phosphor particle different from the plurality of first phosphor particles, and the plurality of first phosphor particles are Ce. Was activated (Y _x Gd _1-x ) ₃ (Al _y Ga _1-y ) ₅ O ₁₂ (0.5 ≦ x ≦ 1, 0.5 ≦ y ≦ 1), or Ce was activated (La). _1-x1 , Y _x1 ) ₃ Si ₆ N ₁₁ (0 ≤ x 1 ≤ 1) was included, and the second fluorophore particles were Ce-activated (La _1-x2 , Y _x2 ) ₃ Si ₆ N ₁₁ (La 1-x2, Y x2). 0 ≦ x2 ≦ 1, x1 ≠ x2) may be included.

Further, in one aspect of the wavelength conversion element according to the present disclosure, the peripheral region is arranged at a position opposite to the central region of the first top portion, and is arranged away from the support surface from the central region. May also have a protruding second apex, and the radial surface may have a second inclined portion that is inclined toward the support surface side from the second apex toward the central region.

Further, in one aspect of the wavelength conversion element according to the present disclosure, the first apex may be higher than the second apex from the support surface.

Further, in one aspect of the wavelength conversion element according to the present disclosure, the wavelength conversion member has a long shape in a top view of the support surface, and the first top portion thereof is in the longitudinal direction of the wavelength conversion member. It may be placed at the end in the direction perpendicular to.

Further, in one aspect of the wavelength conversion element according to the present disclosure, a reflection member arranged between the wavelength conversion member and the support member may be further provided.

Further, in one aspect of the wavelength conversion element according to the present disclosure, the support member may include silicon (Si), silicon carbide (SiC), sapphire ( _Al2O3 ) _, aluminum nitride (AlN) or diamond.

Further, one aspect of the wavelength conversion element according to the present disclosure includes a support member having a support surface and a wavelength conversion member arranged above the support surface, and the wavelength conversion member generates the first fluorescence. The plurality of first fluorescent particles, the plurality of second fluorescent particles that generate the second fluorescence having a spectrum different from that of the first fluorescence, the plurality of first fluorescent particles, and the plurality of second fluorescent particles. The plurality of first fluorescences which are bonded to the transparent binder and include scattered particles different from the plurality of first phosphor particles and the plurality of second phosphor particles. The body particles contained Ce-activated (La _1-x1 , Y _x1 ) ₃ Si ₆ N ₁₁ (0 ≦ x1 ≦ 1), and the plurality of second fluorophore particles were Ce-activated (La). _1-x2 , Y _x2 ) ₃ Si ₆ N ₁₁ (0≤x2≤1, x1 ≠ x2) is included.

As described above, since the wavelength conversion member includes the first phosphor particles and the second phosphor particles that emit fluorescence having different spectra from each other, the emission light can be more freely adjusted by adjusting the mixing ratio of the particles. The chromaticity coordinates can be adjusted.

Further, in one aspect of the wavelength conversion device according to the present disclosure, the scattered particles may contain a metal oxide or a nitride.

Further, in one aspect of the wavelength conversion element according to the present disclosure, the median diameter of the plurality of first phosphor particles and the plurality of second phosphor particles may be 2 μm or more and 30 μm or less.

Further, in one aspect of the wavelength conversion element according to the present disclosure, the median diameter of the plurality of first phosphor particles and the plurality of second phosphor particles may be 3 μm or more and 9 μm or less.

Further, one aspect of the light emitting device according to the present disclosure is a light emitting device including the wavelength conversion element and an excitation light source for irradiating the wavelength conversion element with excitation light, and the brightness of the light emitted from the light emitting device is It is 1000 cd / mm ² or more.

Further, one aspect of the light emitting device according to the present disclosure is a light emitting device including the wavelength conversion element and an excitation light source for irradiating the wavelength conversion element with excitation light, and the excitation light is on the second top side. Incident diagonally from the radiation surface to the wavelength conversion member, the wavelength conversion member converts the excitation light into wavelength.

Further, one aspect of the lighting device according to the present disclosure may include the light emitting device and a light projecting member to which the light emitted from the light emitting device is incident and emits the projected light.

Further, in one aspect of the lighting device according to the present disclosure, a straight line perpendicular to the optical axis of the excitation light at a position where the excitation light is incident on the wavelength conversion member is included, and includes a straight line parallel to the support surface. The projected light may be emitted from the plane toward the excitation light source with respect to a plane perpendicular to the support surface.

According to the present disclosure, it is possible to provide a wavelength conversion element capable of sufficiently converting excitation light into fluorescence and having increased mechanical intensity, and a light emitting device and a lighting device provided with the wavelength conversion element.

FIG. 1 is a schematic cross-sectional view showing the configuration of the wavelength conversion element of the first embodiment. FIG. 2 is a diagram showing the shape of the support surface of the wavelength conversion element according to the first embodiment in a top view. FIG. 3 is a photograph of a cross section of the wavelength conversion element according to the first embodiment observed with a scanning electron microscope. FIG. 4 is a schematic cross-sectional view showing the configuration of the lighting device according to the first embodiment. FIG. 5 is an enlarged view of the vicinity of the wavelength conversion element of the light emitting device according to the first embodiment. FIG. 6 is a diagram showing optical characteristics of the wavelength conversion element according to the first embodiment. FIG. 7 is a graph showing the measurement result of the brightness of the emitted light emitted from the wavelength conversion member according to the first embodiment. FIG. 8 is a graph showing the measurement results of each surface shape when the wavelength conversion member of the wavelength conversion element according to the first embodiment is manufactured by three different methods. FIG. 9 is a schematic cross-sectional view showing the configuration of the wavelength conversion element according to the first modification of the first embodiment. FIG. 10 is a schematic diagram illustrating the configuration of the light emitting device and the lighting device according to the second modification of the first embodiment. FIG. 11 is a top view showing the configuration of the wavelength conversion element according to the second modification of the first embodiment. FIG. 12 is a schematic cross-sectional view showing the configuration of the wavelength conversion element according to the second embodiment. FIG. 13 is a photograph of a cross section of the wavelength conversion element according to the second embodiment observed with a scanning electron microscope. FIG. 14 is a graph showing a spectrum of emitted light when the wavelength conversion element according to the second embodiment is irradiated with excitation light having a peak wavelength of 447 nm. FIG. 15 is a graph showing changes in the chromaticity coordinates of the emitted light when the ratio of the first phosphor particles and the scattered particles is changed in the wavelength conversion element according to the second embodiment. FIG. 16 is a graph showing the results of measuring the peak wavelength dependence of the excitation light of the chromaticity coordinates of the emitted light in the wavelength conversion element according to the second embodiment. FIG. 17 is a diagram showing the refractive index and thermal conductivity of a material that can constitute a wavelength conversion member. FIG. 18 shows the temperature of the quantum efficiency of the La ₃ Si ₆ N ₁₁ : Ce phosphor used in the wavelength conversion member according to the third embodiment and the Y ₃ Al ₅ O ₁₂ : Ce phosphor used in the first embodiment. It is a figure which shows the dependency. FIG. 19 is a diagram showing the characteristics of a light emitting device equipped with the wavelength conversion element according to the third embodiment. FIG. 20 is a graph showing the results of measuring the luminance distribution in the light emitting region on the surface of the phosphor when the drive current of the semiconductor light emitting device of the light emitting device according to the third embodiment is 2.3 amperes. FIG. 21 is a schematic cross-sectional view showing the configuration of the wavelength conversion element according to the fourth embodiment. FIG. 22 is a graph showing the spectral characteristics of the emitted light of the light emitting device using the wavelength conversion element according to the fourth embodiment. FIG. 23 is a diagram showing changes in the chromaticity coordinates of the emitted light when the configuration of the wavelength conversion element is changed in the light emitting device equipped with the wavelength conversion element according to the fourth embodiment. FIG. 24A is a schematic cross-sectional view showing the configuration of the lighting device according to the fifth embodiment. FIG. 24B is an enlarged cross-sectional view of the wavelength conversion element according to the fifth embodiment and its surroundings. FIG. 24C is a schematic perspective view showing the lighting device according to the fifth embodiment and the projection image projected from the lighting device. FIG. 24D is a photograph showing the shape of the wavelength conversion member according to the fifth embodiment. FIG. 24E is a graph showing the first measurement result of the film thickness of the wavelength conversion element according to the fifth embodiment. FIG. 24F is a graph showing the second measurement result of the film thickness of the wavelength conversion element according to the fifth embodiment. FIG. 24G is a graph showing a third measurement result of the film thickness of the wavelength conversion element according to the fifth embodiment. FIG. 24H is a graph showing the color distribution in the light emitting region of the wavelength conversion element according to the fifth embodiment. FIG. 25A is a schematic cross-sectional view showing the wavelength conversion element and the irradiation direction of the excitation light in the light emitting device according to the sixth embodiment. FIG. 25B is a graph showing the luminance distribution of the wavelength conversion element of the light emitting device according to the sixth embodiment. FIG. 25C is a table showing an outline of the experimental results of the light emitting device according to the sixth embodiment. FIG. 26 is a diagram illustrating a configuration of a conventional light emitting device.

Hereinafter, each embodiment will be described with reference to the drawings. It should be noted that all of the embodiments described below show a specific example of the present disclosure. Therefore, the numerical values, shapes, materials, components, the arrangement positions of the components, the connection form, and the like shown in the following embodiments are examples and do not limit the present disclosure. Therefore, among the components in the following embodiments, the components not described in the independent claims of the present disclosure are described as arbitrary components. The drawings are schematic or conceptual, and the relationship between the thickness and width of each part, the ratio of the sizes between the parts, etc. are not always the same as the actual ones. Even if the parts are substantially the same, the dimensions and ratio may be different depending on the drawing. Duplicate explanations for substantially the same configuration may be omitted.

Further, in the present specification, the term "upper" does not refer to the upward direction (vertically upward) in absolute spatial recognition, but is defined by a relative positional relationship based on the stacking order in the laminated configuration. Used as. Also, the term "upper" is used not only when the two components are spaced apart from each other and another component exists between the two components, but also when the two components are in close contact with each other. It also applies when the two components are placed and touch.

(Embodiment 1)
Hereinafter, the wavelength conversion element according to the first embodiment will be described with reference to the drawings.

[Basic configuration]
FIG. 1 is a schematic cross-sectional view showing the configuration of the wavelength conversion element 1 according to the present embodiment. As shown in FIG. 1, the wavelength conversion element 1 according to the present embodiment is an element including a support member 2 having a support surface 2a and a wavelength conversion member 40 arranged above the support surface 2a.

The support member 2 is a member that supports the wavelength conversion member 40. In the present embodiment, the support member 2 has a plate-like shape and supports the wavelength conversion member 40 via the reflection member 3 arranged on the planar support surface 2a. The support member 2 functions as a heat sink that dissipates the heat generated by the wavelength conversion member 40.

The wavelength conversion member 40 includes a plurality of first phosphor particles 41 that absorb the excitation light 84 and radiate fluorescence, and a transparent binder 42 that binds the plurality of first phosphor particles 41. The wavelength conversion member 40 has a joint surface 7 located on the support surface 2a side and a radiation surface 6 located on the opposite side of the support surface. The radiation surface 6 faces the junction surface 7, and includes a radiation surface 6 to which the excitation light 84 is incident and emits the emitted light 95. Of the support surface 2a, the region facing the joint surface 7 is the arrangement region 2d in which the wavelength conversion member 40 is arranged. In this embodiment, the arrangement region 2d is a plane.

The emitted light 95 including the first emitted light 85 and the second emitted light 91 is emitted from the emission surface 6 of the wavelength conversion member 40. The first emitted light 85 is the scattered excitation light 84. The second emitted light 91 is fluorescence obtained by converting the excitation light 84 into a wavelength. Further, the radiation surface 6 of the wavelength conversion member 40 includes a plurality of micro-convex portions 5a and a plurality of micro-concave portions 5b.

The radial surface 6 includes a peripheral region 6a including the peripheral edges E1 and E2 of the radial surface 6 and a central region 6b surrounded by the peripheral region 6a. At least a portion of the peripheral region 6a has a first apex P1 protruding from the central region 6b in a direction away from the support surface 2a. The radial surface 6 has a first inclined portion S1 inclined toward the support surface 2a from the first top portion P1 toward the central region 6b. The radial surface 6 is microscopically formed with a large number of minute irregularities, but macroscopically, the radial surface 6 is inclined toward the support surface 2a from the first top portion P1 toward the central region 6b. It has one inclined portion S1. The wavelength conversion member 40 includes a plurality of first phosphor particles 41 made of the same material in the central region 6b and the first top portion P1.

In the present embodiment, a plurality of minute convex portions 5a are formed on the radial surface 6 in the first inclined portion S1. The minute convex portion 5a referred to here is a convex portion that is detected in large numbers when the radial surface 6 is viewed microscopically. The dimension of the minute convex portion 5a in the direction parallel to the support surface 2a is 50% or less of the film thickness of the wavelength conversion member 40. Further, the central region 6b includes a flat portion F1 having a gentler inclination than the first inclined portion S1. In the example shown in FIG. 1, the flat portion F1 is a part of the central region 6b, but the entire central region 6b may be the flat portion F1. Further, the peripheral region 6a may include the flat portion F1. Further, the flat portion F1 referred to here may have minute irregularities, and may be macroscopically flat. For example, the flat portion F1 may include irregularities whose dimensions in the direction parallel to the support surface 2a are about 50% or less of the film thickness of the wavelength conversion member 40.

Further, in the present embodiment, the peripheral region 6a is arranged at a position opposite to the central region 6b from the first top P1, and protrudes from the central region 6b in a direction away from the support surface 2a. It has a top P2. The radial surface 6 has a second inclined portion S2 inclined toward the support surface 2a from the second top portion P2 toward the central region 6b.

As described above, in the present embodiment, the film thickness of the wavelength conversion member 40 is thicker in the vicinity of the first top portion P1 and the second top portion P2 of the peripheral region 6a than in the central region 6b. That is, a concave shape is formed from the first top portion P1 to the second top portion P2. As _shown in _FIG . 1, the film thickness de at the first top portion P1 of the wavelength conversion member 40 is thicker than the film thickness _dc in the central region 6b (de> _dc ).

In the present embodiment, the height from the support surface 2a to the first top P1 is higher than the height from the support surface 2a to the second top P2. Here, as will be described later, the excitation light 84 is obliquely incident on the central region 6b of the wavelength conversion member 40. Therefore, when the height from the support surface 2a to the first top P1 is higher than the height from the support surface 2a to the second top P2 as in the present embodiment, the excitation light 84 is emitted from the second top P2 side. By incident in the direction toward the first top P1, it is possible to reduce the interference of the excitation light 84 by the peripheral region 6a of the wavelength conversion member 40. Therefore, the proportion of the component incident on the central region 6b in the excitation light 84 can be increased. That is, the utilization efficiency of the excitation light 84 can be improved.

In the wavelength conversion member 40 shown in FIG. 1, in the cross section passing through the central region 6b, as described above, one peripheral region 6a (peripheral region 6a on the right side of FIG. 1) has a first top portion P1 protruding from the central region 6b. It is formed. The radial surface 6 has a third inclined portion S3 that is steeply inclined toward the support surface 2a from the first top portion P1 toward the peripheral edge E1 of the radial surface 6. A second apex P2 is similarly formed in the other peripheral region 6a (the peripheral region 6a on the left side of FIG. 1). The radial surface 6 has a fourth inclined portion S4 that is steeply inclined toward the support surface 2a from the second top P2 toward the peripheral edge E2 of the radial surface 6.

The reflection member 3 is a member that is arranged between the wavelength conversion member 40 and the support member 2 and reflects at least one of the excitation light and the fluorescence. In the present embodiment, the reflective member 3 is a reflective film formed on the support surface 2a of the support member 2.

The function of the wavelength conversion element 1 having the above-described configuration will be described. In the wavelength conversion element 1 according to the present embodiment, the excitation light 84 emitted from an excitation light source (not shown) is incident on the radiation surface 6 of the wavelength conversion member 40. In this embodiment, laser light is used as the excitation light 84. At this time, the excitation light 84 is light having a high light density in which light having a strong light intensity is converged in a predetermined small region. In FIG. 1, most of the excitation light 84 incident on the wavelength conversion element 1 is incident on the excitation region 150, which is a part of the central region 6b of the radiation surface 6.

The excitation light 84 incident on the excitation region 150 is incident on the first phosphor particles 41 or the transparent coupling material 42 of the wavelength conversion member 40. In the radiation surface 6 and the inside of the wavelength conversion member 40, there is an interface between media having different refractive indexes, that is, an interface between air and the wavelength conversion member 40 and an interface between the first phosphor particles 41 and the transparent binder 42. exist. Therefore, the excitation light 84 incident on the wavelength conversion member 40 is diffusely reflected or multiple-reflected inside the radiation surface 6 and the inside of the wavelength conversion member 40, and a part of the excitation light 84 is the first emitted light 85 (shown in FIG. 1). It is radiated from the wavelength conversion member 40 as a solid line arrow). At this time, the first emitted light 85 is diffusely reflected or multiple-reflected by the radiation surface 6 of the wavelength conversion member 40 and the interface existing inside. Therefore, in the first emitted light 85, the directivity of the excitation light 84 composed of the laser light is reduced. Therefore, the wavelength conversion element 1 can radiate the first emitted light 85 as light whose emission direction is omnidirectional. That is, in the wavelength conversion element 1 according to the present embodiment, a sufficient scattering action can be ensured.

On the other hand, a part of the excitation light 84 is absorbed by the first phosphor particles 41, becomes wavelength-converted fluorescence, and is radiated. This fluorescence is diffusely reflected or multiple-reflected directly or at the interface between the first phosphor particles 41 and the transparent binder 42, and then the second emitted light 91 from the radiation surface 6 of the wavelength conversion member 40 (in FIG. 1). It is radiated as a broken line arrow).

Therefore, the emission light 95, which is a mixed light in which the first emission light 85 and the second emission light 91 are mixed, is emitted from the radiation surface 6 of the wavelength conversion element 1. At this time, the region emitted by the emitted light 95 is from the light emitting region 151, which is a region larger than the excited region 150, because both the first emitted light 85 and the second emitted light 91 are multiple-reflected in the wavelength conversion member 40. Emitted.

Hereinafter, more specific embodiments will be described, including any non-essential components.

As shown in FIG. 1, in the wavelength conversion element 1, the reflection member 3 is arranged on the support surface 2a of the support member 2, and the wavelength conversion member 40 is arranged on the surface of the reflection member 3. The reflective member 3 includes a first reflective film 3b mainly made of metal, a second reflective film 3c mainly made of a dielectric multilayer film, and an adhesion layer 3a for bringing the support member 2 and the first reflective film 3b into close contact with each other. including.

The wavelength conversion member 40 includes a plurality of first phosphor particles 41 and a transparent binder 42 for binding the plurality of first phosphor particles 41. The plurality of first phosphor particles 41 may be dispersed in the transparent binder 42.

When the wavelength of the excitation light of the first phosphor particles 41 is blue light of 420 nm or more and 490 nm or less, cerium (Ce) is activated (Y _x Gd _1-x ) ₃ (Al _y Ga _1-y ). ) ₅ O ₁₂ (0.5 ≦ x ≦ 1, 0.5 ≦ y ≦ 1) or other yttrium-aluminum-garnet (YAG) -based phosphors can be used. The median diameter D50 of the first phosphor particles 41 included in the wavelength conversion member is, for example, 2 μm or more and 30 μm or less. When such a first phosphor particle 41 is used, the film thickness of the wavelength conversion member 40 is, for example, 2 μm or more and 50 μm or less in the excited region 150.

Other materials constituting the first phosphor particles 41 include europium (Eu) activated α-SiAlON, Eu activated (Ba, Sr) Si ₂ O ₂ N ₂ , etc., depending on the wavelength of the light emitted from the phosphor. Can be used. At this time, the first phosphor particles 41 are heat-conducted because the heat generated by the first phosphor particles 41 is quickly exhausted to the support member 2 when the excitation light 84 is converted into the second emitted light 91. It is composed of a material having a high rate, for example, a material having a high rate of 5 W / mK or more.

The transparent binder 42 may be made of a transparent material having a large difference in refractive index from the first phosphor particles 41. This makes it possible to enhance the light scattering effect at the interface between the first phosphor particles 41 and the transparent binder 42. The material forming the transparent binder 42 is, for example, a transparent material containing silicon (Si) and oxygen (O) as main components, and examples thereof include glass, silsesquioxane, and silicone.

In the wavelength conversion member 40, the plurality of first phosphor particles 41 quickly transfer the heat generated by the first phosphor particles 41 to the support member 2 when the excitation light 84 is converted into the second emitted light 91. It may have a configuration capable of exhausting heat. Specifically, the plurality of first phosphor particles 41 having a higher thermal conductivity than the transparent binder 42 are arranged close to each other. Then, the transparent binder 42 is filled between the plurality of first phosphor particles 41. At this time, since the excitation light 84 is scattered at the interface between the first phosphor particles 41 and the transparent binder 42, the larger the interface area is, the better. Therefore, the adjacent first phosphor particles 41 may be close to each other but separated from each other at a wavelength equal to or higher than the wavelength of the excitation light 84, and the transparent binder 42 may be filled between them. At this time, there is no problem even if a part of the adjacent first phosphor particles 41 come into contact with each other.

The material forming the support member 2 is a material having a high thermal conductivity and a small difference in thermal expansion coefficient from the transparent coupling material 42 in order to absorb the heat generated by the wavelength conversion element 1 more efficiently. May be good. For example, the material forming the support member 2 may be a material having a thermal conductivity of 20 W / mK or more and a coefficient of thermal expansion of 1 × 10 ^-5 / K or less. Specifically, the support member 2 may include silicon (Si), silicon carbide (SiC), sapphire (Al ₂ O ₃ ), aluminum nitride (AlN), diamond, or the like. Further, the support member 2 may be a semiconductor crystal substrate or a ceramic substrate made of these materials.

The reflective member 3 has, for example, a high reflectance in the spectrum of the excitation light 84 and the spectrum of the fluorescence generated in the first phosphor particles 41. That is, of the excitation light 84 incident on the wavelength conversion member 40 and the first emitted light 85 and the second emitted light 91 generated by the wavelength conversion member 40, the light that has reached the reflection member 3 is efficiently converted into the wavelength conversion member 40. It has the function of reflecting to the side. Therefore, the first reflective film 3b is specifically formed by using a metal film such as aluminum (Al), silver (Ag), a silver alloy, or platinum (Pt). Further, the second reflective film 3c is formed as a multilayer film by using a dielectric film such as SiO ₂ , Al ₂ O ₃ , ZrO ₂ , and TiO ₂ .

The support surface 2a of the support member 2 on which the reflection member 3 is formed may be flat and mirror-finished. As a result, the reflective member 3 formed on the support surface 2a can be formed of a flat film. Therefore, the first emitted light 85 and the second emitted light 91 that have reached the reflecting member 3 can be efficiently reflected.

[Detailed configuration and manufacturing method]
Subsequently, a specific shape and dimensions of the wavelength conversion element 1 will be described together with a manufacturing method. The method for manufacturing the wavelength conversion element 1 will be specifically described including a method that is not essential.

First, a wafer-shaped member that is the basis of the support member 2 is prepared. In the present embodiment, a wafer which is a silicon substrate having a diameter of 3 inches and a thickness of 0.38 mm is prepared as the support member 2. As the silicon substrate, a silicon substrate whose support surface 2a side is mirror-finished and flat by mechanochemical polishing is used.

Subsequently, the reflective member 3 is formed by forming the adhesion layer 3a, the first reflective film 3b, and the second reflective film 3c in order on the support surface 2a, which is one of the main surfaces of the support member 2, by a vapor deposition method or the like. do. More specifically, the reflective member 3 is a contact layer 3a composed of Al ₂ O ₃ having a thickness of 127 nm and Ni having a thickness of 27 nm, and Ag having a thickness of 150 nm, in order from the support member 2 side. 1 Includes a reflective film 3b and a second reflective film 3c composed of Al ₂ O ₃ having a thickness of 75 nm, SiO ₂ having a thickness of 25 nm, and TiO ₂ having a thickness of 28 nm. The second reflective film 3c has both a function of a surface protective layer for protecting the first reflective film 3b and a reflective layer for suppressing light absorption in the first reflective film 3b made of metal. .. Further, the adhesion layer 3a suppresses the reflection member 3 from peeling from the support member 2 in the dicing step when the wafer described later is divided into individual wavelength conversion elements 1.

Subsequently, a screen mesh printing mask having a plurality of predetermined openings is arranged above the support surface 2a of the support member 2. At this time, the openings are two-dimensionally formed in the plane at a pitch of 2 mm or more and 10 mm or less. In the present embodiment, one having a pitch of 3.5 mm and one having a pitch of 5 mm were produced. For example, at a pitch of 5 mm, about 100 openings are formed within a range of 3 inches in diameter. The screen mesh printing mask is formed by weaving a metal fiber such as stainless steel or a synthetic fiber such as polyester. By printing through the mesh of the mesh, the volume of the paste that passes through is smaller than that of an aperture mask such as metal, so that a thin film can be formed by printing. Further, the shape of the wavelength conversion member 40 can be freely formed by using a shape of the opening that matches the shape of the desired wavelength conversion member 40. Further, the thickness of the screen mesh printing mask can be set according to the desired film thickness of the wavelength conversion member 40 of the wavelength conversion element 1.

Subsequently, a fluorescent paste is prepared by dissolving the raw material constituting the transparent binder 42 in an organic solvent and mixing the first fluorescent particles 41 with the raw material. At this time, using a Ce-activated Y3 Al ₅ O ₁₂ phosphor having a median diameter D50 of ₃ , 4, 6, and 9, respectively, the median diameter of the first phosphor particles 41 is changed as a parameter to form a phosphor paste. To make. Further, in the wavelength conversion member 40 according to the present embodiment, a transparent material whose main component is polymethylsilsesquioxane was used as the transparent binder 42. Therefore, as the fluorescent paste, a transparent binder in which silsesquioxane was dissolved in an organic solvent was used in which a plurality of the above-mentioned first fluorescent particles 41 were dispersed. At this time, the organic solvent is selected to have a boiling point lower than the temperature in the high temperature curing step described later. Then, after the high temperature curing step, the mixing ratio is determined so that the ratio of the first phosphor particles 41 and the transparent binder 42 becomes a desired value. Further, the amount of the organic solvent is determined so that the above-mentioned fluorescent paste has a desired viscosity.

Subsequently, the phosphor paste produced in the above step is injected into the opening of the screen mesh printing mask above the wafer. At this time, the fluorescent paste is arranged so as to sufficiently fill the opening.

Subsequently, the unnecessary fluorescent paste overflowing from the opening is removed with a squeegee, and the screen mesh printing mask is pressed against the support surface 2a of the wafer and released to release the fluorescent paste filled in the opening from the support surface 2a. Transfer to.

Subsequently, the print mask is removed, and the wafer on which a plurality of fluorescent pastes are formed on the surface in a predetermined pattern is heated by a high temperature furnace or the like at a temperature of, for example, about 200 ° C. for about 2 hours. By this high temperature curing step, the raw materials of the transparent binder in the phosphor paste are condensed, and a wafer-shaped wavelength conversion element in which a plurality of first phosphor particles 41 are fixed is formed in the transparent binder 42. The wavelength conversion element 1 manufactured in this manner will be described with reference to FIG.

FIG. 2 is a diagram showing the shape of the support surface 2a of the wavelength conversion element 1 according to the present embodiment in a top view. FIG. 2 shows a photograph (a) in a top view of a part of the wavelength conversion element 1 manufactured by the above manufacturing process, and an enlarged plan view of one wavelength conversion element 1 shown in the photograph (a). b) and is shown. The plan view (b) schematically shows the shapes of the wavelength conversion member 40 and the support member 2 in the wavelength conversion element 1. The frame shown by the broken line in the photograph (a) and the plan view (b) shows the outline of the support member 2 after being individualized as described later.

In the present embodiment, as the screen mesh printing mask, a mask having circular openings having a diameter of 2.6 mm formed at a pitch of 3.7 mm is used, and a plurality of wavelength conversion members 40 are formed on the wafer.

Next, the wafer to which a plurality of wavelength conversion members 40 having a film thickness of 2 μm or more and 50 μm or less produced by the above steps are fixed is divided by dicing. Specifically, a dicing blade having a blade width of 0.2 mm is used to divide the dicing blade at a pitch of 3.7 mm. At this time, the divided portion having a width of 0.2 mm corresponding to the thickness of the dicing blade is cut by the dicing blade, so that the 3.5 mm square wavelength conversion element 1 as shown in the plan view (b) of FIG. 2 is manufactured. To.

By the above manufacturing method, the wavelength conversion element 1 in which the wavelength conversion member 40 having a film thickness of 2 μm or more and 50 μm or less is formed on the support member 2 can be easily manufactured.

The features of the wavelength conversion element 1 manufactured in this manner will be described in more detail with reference to FIGS. 2 and 3. FIG. 3 is a photograph of a cross section of the wavelength conversion element 1 according to the present embodiment observed with a scanning electron microscope (SEM). In FIG. 3, a cross section taken along the line III-III shown in FIG. 2 is shown. In addition, FIG. 3 shows a cross-sectional photograph (a) and an enlarged photograph (b) in which a part thereof is enlarged. The enlarged photograph (b) is an enlarged photograph of the broken line frame portion of the cross-sectional photograph (a). The embedded resin shown in FIG. 3 is a resin used for observation with a scanning electron microscope, and is not a component of the wavelength conversion element 1.

As shown in FIG. 2, in the top view of the support surface 2a, the peripheral edge portion of the support member 2 is exposed from the wavelength conversion member 40. That is, in the wavelength conversion element 1, the arrangement region of the wavelength conversion member 40 is formed so as to be smaller than the outer shape of the support member 2. By forming the wavelength conversion element 1 in this way, when the wavelength conversion element 1 is used as a component of a light emitting device, for example, a region around the wavelength conversion element 1 in which the wavelength conversion member 40 is not formed is formed by a collet or the like. By chucking and transporting, it can be easily fixed to a place where the wavelength conversion element 1 is arranged, such as a base of a light emitting device.

Further, as shown in FIG. 3, the wavelength conversion element 1 includes a support member 2 which is a silicon substrate, a reflection member 3 composed of a silver film, a dielectric multilayer film, and the like arranged on the support member 2, and a reflection member. 3 The wavelength conversion member 40 arranged on the top 3 is provided. The wavelength conversion member 40 is composed of a plurality of first phosphor particles 41 and a transparent binder 42 composed of silsesquioxane. In the example shown in FIG. 3, the film thickness of the wavelength conversion member 40 was about 20 μm. Further, although the first phosphor particles 41 are dispersed in the transparent binder 42, the adjacent first phosphor particles 41 are close to each other. By arranging in this way, the heat generated by the first phosphor particles 41 can be efficiently conducted to the support member 2 via the adjacent first phosphor particles 41. That is, the heat generated by the first phosphor particles 41 can be mainly conducted to the support member 2 through the first phosphor particles 41 having a higher thermal conductivity than the transparent binder 42. Further, a plurality of minute convex portions 5a are formed on the surface (radiating surface 6) of the wavelength conversion member 40. At least a part of the plurality of micro-convex portions 5a is formed by projecting a part of the plurality of first phosphor particles 41 on the radiation surface 6. That is, a minute convex portion 5a is formed along the surface of the first phosphor particles 41. A minute concave portion 5b is formed next to the minute convex portion 5a. By forming minute irregularities on the surface of the wavelength conversion member 40 in this way, the excitation light 84 can be efficiently scattered. Further, as shown in the cross-sectional photograph (a) of FIG. 3, gentle unevenness is also formed at intervals of about 5 to 10 particles. The period of the gentle unevenness, that is, the interval between the adjacent convex portions or the interval between the adjacent concave portions is larger than 50% of the average film thickness of the uneven portion of the wavelength conversion member 40 and is about 5 times or less. As described above, the excitation light 84 can be scattered more efficiently by forming the gentle unevenness comparatively smooth with the minute unevenness on the surface of the wavelength conversion member.

[Light emitting device and lighting device]
Subsequently, a light emitting device and a lighting device using the wavelength conversion element according to the first embodiment will be described in detail with reference to FIG. FIG. 4 is a schematic cross-sectional view showing the configuration of the lighting device 201 according to the present embodiment.

As shown in FIG. 4, the lighting device 201 according to the present embodiment includes a light emitting device 101 and a light projecting member 220.

The light projecting member 220 is an optical member to which the emitted light 95 from the light emitting device 101 is incident and emits the projected light 96. In the present embodiment, the light projecting member 220 is a curved mirror such as a parabolic mirror.

The light emitting device 101 according to the present embodiment mainly includes the above-mentioned wavelength conversion element 1, the semiconductor light emitting device 110, and the condensing optical member 120.

In the light emitting device 101, the semiconductor light emitting device 110 and the wavelength conversion element 1 are fixed to the base 50. The base 50 is a housing made of a metal such as an aluminum alloy.

The semiconductor light emitting device 110 is an excitation light source that irradiates the wavelength conversion element with excitation light. In the present embodiment, the semiconductor light emitting device 110 is, for example, a TO-CAN type semiconductor laser, and is connected to the printed circuit board 160. A semiconductor light emitting element 111 is mounted on the semiconductor light emitting device 110. The semiconductor light emitting device 110 is inserted into an opening formed in the bottom surface of the base 50. The emitted light 81 emitted from the semiconductor light emitting device 111 is emitted above FIG.

The condensing optical member 120 includes a lens 120a and a reflecting optical element 120b having a reflecting surface. The lens 120a and the reflective optical element 120b are arranged above the semiconductor light emitting device 110.

The light emitting device 101 further includes a printed circuit board 160 on which a photodetector 130 is mounted. The printed circuit board 160 is arranged on the bottom surface side of the base 50, and a connector 170 for connecting to an external circuit is connected to the printed circuit board 160.

The semiconductor light emitting device 111 is a multimode laser having an optical waveguide having a width of 10 μm or more. The reflective optical element 120b is, for example, a reflective mirror in which a plurality of concave mirror surfaces are formed. With this configuration, the emitted light 81 emitted upward from the semiconductor light emitting device 111 in FIG. 4 becomes parallel light from the lens 120a and is incident on the reflected optical element 120b. The emitted light 81 incident on the reflecting optical element 120b is reflected downward in FIG. 4 on the concave mirror surface of the reflecting optical element 120b, and becomes the excitation light 84 that irradiates the wavelength conversion element 1 from diagonally above. That is, a part of the excitation light 84 irradiated to the wavelength conversion element 1 is converted by the wavelength conversion member 40 of the wavelength conversion element 1, and the first emitted light 85 composed of scattered light and the second emission composed of fluorescence are emitted. The emitted light 95 is composed of the emitted light 91 and is emitted from the light emitting device 101.

The emitted light 95 emitted from the light emitting device 101 becomes projected light 96 which is substantially parallel light in the light projecting member 220, and is emitted from the lighting device 201.

The light emitting device 101 includes a connector 170. The connector 170 is a connector that can be connected to an external circuit. As a result, electric power can be applied to the semiconductor light emitting device 110 and the printed circuit board 160 from the outside. The light emitting device 101 further includes a photodetector 130 such as a photodiode. The photodetector 130 is mounted on the printed circuit board 160. As a result, the light from the wavelength conversion element 1 can be received and a detection signal indicating the light emission state of the light emitting device 101 can be output to the outside. Further, for example, a translucent member 140 which is a cover glass is arranged above the wavelength conversion element 1. The translucent member 140 is attached to a holder 53 made of a metal such as aluminum like the base 50, and is fixed so as to cover the wavelength conversion element 1 and the condensing optical member 120 fixed to the base 50. .. Thereby, the condensing optical member 120 and the wavelength conversion element 1 constituting the light emitting device 101 can be protected. In the light emitting device 101 according to the present embodiment, the semiconductor light emitting device 110 and the condensing optical member 120 are arranged above the printed circuit board 160 used for electrical wiring, and diagonally above the wavelength conversion element 1 arranged below. The excitation light 84 can be incident from the light. Therefore, the light emitting device 101 can be made thinner.

Further, the excitation light 84 is obliquely incident on the radiation surface 6 from the second top P2 side, and the wavelength conversion member 40 wavelength-converts the excitation light 84. In this way, by incident the excitation light 84 in the direction from the second apex P2 side toward the first apex P1, it is possible to reduce the fact that the excitation light 84 is blocked by the peripheral region 6a of the wavelength conversion member 40. Therefore, the proportion of the component incident on the central region 6b in the excitation light 84 can be increased. That is, the utilization efficiency of the excitation light 84 can be improved.

Further, in the above configuration, the beam shape of the excitation light 84 is shaped by using the reflection optical element 120b. With this configuration, the light intensity distribution of the excitation light 84 irradiated to the wavelength conversion element 1 can be made uniform.

Further, in the present embodiment, as shown in FIG. 4, the projected light 96 is emitted in the direction substantially opposite to the direction in which the excitation light 84 is incident on the wavelength conversion member 40. In other words, it is a straight line orthogonal to the optical axis of the excitation light 84 at the position where the excitation light 84 is incident on the wavelength conversion member 40, includes a straight line parallel to the support surface, and with respect to a plane PV perpendicular to the support surface 2a. , The projected light 96 is emitted from the plane PV toward the excitation light source (semiconductor light emitting device 110).

Further, the light emitting device 101 emits light by using a semiconductor light emitting device 110 which is a semiconductor laser device and a wavelength conversion element 1 including a phosphor. Therefore, light having higher brightness can be emitted from the wavelength conversion element 1 than when a light emitting diode or the like is used. Then, the light emitted from the light emitting device 101 can be irradiated far away by using the light projecting member 220.

[Fixing of wavelength conversion element]
In the light emitting device 101 according to the present embodiment, a detailed configuration in the vicinity of the fixed portion of the wavelength conversion element 1 will be described with reference to the drawings. FIG. 5 is an enlarged view of the vicinity of the wavelength conversion element 1 of the light emitting device 101 shown in FIG.

The wavelength conversion element 1 has a rectangular support member 2 in a top view of the support surface 2a. Then, the wavelength conversion member 40 is formed on the reflection member 3 of the support surface 2a.

The base 50 of the light emitting device 101 is formed with a concave storage portion 50a having a rectangular shape when viewed from above and one size larger than the outer shape of the support member 2. Then, the wavelength conversion element 1 is fixed to the bottom surface of the storage portion 50a.

The wavelength conversion element 1 is fixed to the base 50 by an adhesive member 55. As the adhesive member 55, for example, an adhesive resin mainly containing a silicone resin, an epoxy resin, or the like, or a solder mainly containing AuSn, SnAgCu, or the like can be used.

Further, in the light emitting device 101 according to the present embodiment, the light shielding cover 51 is arranged above the storage unit 50a in which the wavelength conversion element 1 is stored in the base 50. The light-shielding cover 51 is formed with an opening for passing the excitation light 84 and the emitted light 95, and is composed of a metal plate having a black surface. Specifically, it is a black-painted stainless steel plate or an aluminum alloy plate whose surface is black-anodized. The light-shielding cover 51 is arranged so as to cover at least a part of the peripheral region 6a in the wavelength conversion member 40 of the wavelength conversion element 1. The light-shielding cover 51 is firmly fixed to the base 50 with, for example, a screw 52. As a result, the excitation light 84 is irradiated to the region of the support surface 2a of the wavelength conversion element 1 where the wavelength conversion member 40 is not formed, and the generation of stray light is suppressed.

Further, the emitted light 95 emitted from the wavelength conversion member 40 in the direction of the side wall 50b of the storage portion 50a is attenuated by multiple reflection in the space between the storage portion 50a and the light-shielding cover 51. As a result, it is possible to suppress the inclusion of stray light in the projected light 96 of the lighting device.

Further, the wavelength conversion member 40 of the wavelength conversion element 1 has a concave shape in which the thickness of the central region 6b is thin and the thickness of the peripheral region 6a is thicker than that of the central region 6b. Therefore, when manufacturing the light emitting device 101, it is possible to prevent the light shielding cover 51 from coming into contact with the light emitting region located in the central region 6b of the wavelength conversion member 40. That is, even if the light-shielding cover 51 approaches the wavelength conversion member 40, it contacts the peripheral region 6a before the central region 6b of the wavelength conversion member 40, so that light is emitted from the flat portion F1 of the central region 6b of the wavelength conversion member 40. Hard to contact region 151. Therefore, it is possible to suppress deterioration of the optical characteristics of the emitted light 95 of the wavelength conversion element 1.

Further, in the present embodiment, a part or all of the space between the side surface of the support member 2 and the storage portion 50a may be filled with the adhesive member 55. As a result, the heat transferred from the wavelength conversion member 40 to the support member 2 can be more effectively conducted to the base 50.

With the above configuration, the wavelength conversion element 1 according to the present embodiment and the light emitting device 101 using the same can emit high-luminance emitted light. Such a light emitting device 101 can realize a lighting device 201 with a high luminous intensity when the lighting device 201 is configured by using a small light projecting member 220. Therefore, the light emitting device 101 according to the present embodiment is suitable as a light source used for a vehicle headlight or the like.

[Operation and effect]
Subsequently, the operation and effect of the wavelength conversion element 1 according to the present embodiment will be described with reference to the drawings based on the experimental data.

The experimental data was evaluated by mounting the wavelength conversion element 1 on the light emitting device 101 shown in FIG. The brightness of the emitted light 95 from the light emitting device 101 and the surface temperature of the wavelength conversion element 1 are measured by thermography from above of FIG. 4 with the light projecting member 220 removed from the lighting device 201 shown in FIG. did. The method for measuring the surface temperature is not limited to thermography, and other methods may be used.

The light emitting device 101 includes a semiconductor light emitting device 110 for irradiating the wavelength conversion element 1 with the excitation light 84. Further, a reflecting optical element 120b for shaping the beam of the excitation light 84 irradiated to the wavelength conversion element 1 is provided. The wavelength conversion element 1 and the semiconductor light emitting device 110 are firmly fixed to the base 50 with a material having high thermal conductivity in order to dissipate the generated heat to the outside.

As shown in FIG. 1, the wavelength conversion element 1 fixed to the base 50 is irradiated with the excitation light 84 in an oblique direction with respect to the radiation surface 6. The excitation light 84 is a laser beam having a peak wavelength of 430 nm or more and 470 nm or less. A part of the excitation light 84 irradiated on the radiation surface 6 is absorbed by the first phosphor particles 41 of the wavelength conversion member 40, converted into fluorescence which is light of another wavelength, and radiates from the radiation surface 6 in all directions. It is emitted as the second emitted light 91 to be generated.

On the other hand, among the light incident on the wavelength conversion member 40, the light not absorbed by the first phosphor particles 41 is reflected on the surface or inside of the wavelength conversion member 40, and the first emitted light 85 from the wavelength conversion member 40. Is radiated as. At this time, the light reflected inside the wavelength conversion member 40 is multiple-reflected by the plurality of first phosphor particles 41 and is emitted from the radiation surface 6 of the wavelength conversion member 40. Therefore, the light reflected inside the wavelength conversion member 40 is emitted as the first emitted light 85 emitted from the radiation surface 6 of the wavelength conversion member 40 in all directions. On the other hand, with respect to the light reflected on the radiation surface 6 of the wavelength conversion member 40 or near the radiation surface 6 and emitted as the first emitted light 85, the minute protrusions and the minute recesses of the radiation surface 6 of the wavelength conversion member 40. Alternatively, it is diffusely reflected and emitted at the interface between the first phosphor particles 41 existing in the vicinity of the radiation surface 6 and the transparent binder 42. Therefore, the light reflected by the radiation surface 6 or the vicinity of the radiation surface 6 and emitted as the first emitted light 85 is also emitted from the radiation surface 6 of the wavelength conversion member 40 in all directions.

As a result of the above, the emission light 95, which is a mixture of the first emission light 85 and the second emission light 91 emitted in all directions, is emitted from the emission surface 6 of the wavelength conversion member 40. At this time, for example, as shown in FIG. 1, the wavelength conversion member 40 has a concave shape in which the thickness of the central region 6b is thinner than the maximum film thickness of the peripheral region 6a. The central region 6b, which is the bottom surface of the concave shape, has a flat portion F1 having a small change in thickness. Further, the flat portion F1 near the bottom surface portion of the concave shape may be set to be larger than the excitation region 150 of the excitation light 84 and the light emission region 151 of the emitted light 95. As a result, the chromaticity distribution of the emitted light 95 emitted from the wavelength conversion member 40 can be made uniform.

As a result, when the first emitted light 85 is blue light and the second emitted light 91 is yellow light, the wavelength conversion member 40 can emit the emitted light 95 composed of white light having a small chromaticity distribution deviation.

Subsequently, with reference to FIG. 6, the optical characteristics when the wavelength conversion element 1 of the present embodiment is irradiated with the excitation light 84 having a predetermined light density will be described. FIG. 6 is a diagram showing the optical characteristics of the wavelength conversion element 1 according to the present embodiment.

First, the graph (a) of FIG. 6 is a diagram showing the temperature dependence of the quantum efficiency of the Ce-activated _{Y3 Al 5 O 12} phosphor particles used as the first phosphor particles 41. The quantum efficiency of the Ce-activated _{Y3 Al 5 O 12} phosphor particles decreases as the temperature rises, and when the temperature exceeds 150 ° C., the quantum efficiency begins to decrease sharply.

In the graph (b) of FIG. 6, the wavelength conversion member 40 is irradiated with the excitation light 84, and the excitation light scattered and reflected by the wavelength conversion member 40 and the excitation light 84 are absorbed and converted by the wavelength conversion member 40 and emitted. It is a figure for demonstrating the chromaticity coordinates of the emitted light 95 (white light) which is the mixed color light which is mixed with the fluorescence. In the present embodiment, an excitation light source that emits emitted light, which is a blue laser light having a chromaticity coordinate of (0.161, 0.014), and fluorescence having a chromaticity coordinate of (0.426, 0.547) are used. The experiment was carried out using the emitted phosphor particles (YAG). Therefore, in the graph (b) of FIG. 3, the straight line (trajectory of mixed light) connecting the chromaticity coordinates (0.161, 0.014) and (0.426, 0.547) and the blackbody radiation locus The target of the chromaticity coordinates was (0.317, 0.327), which is the chromaticity coordinates at which and intersect.

In the graphs (c) and (e) of FIG. 6, the wavelength conversion element 1 according to the present embodiment is excited by being shaped into a square shape having an optical output of about 3.2 watts and an irradiation range of about 0.7 mm on each side. This is the result of measuring the relationship between the thickness of the light emitting region portion of the wavelength conversion member 40 and the peak temperature of the surface of the wavelength conversion member 40 when the light 84 is incident. In the graph (c) of FIG. 6, the results of comparison when the median diameter D50 of the first phosphor particles is 3 μm, 4 μm, 6 μm, and 9 μm are shown. Here, the volume ratio between the first phosphor particles 41 and the transparent binder 42 was set to 45:65. Further, in the graph (e) of FIG. 6, the median diameter D50 of the first phosphor particles 41 was set to 6 μm, and the volume ratio of the first phosphor particles 41 and the transparent binder 42 was changed for measurement. 38%, 45%, 55%, and 65% shown in the figure are the ratios of the transparent binder 42 to the wavelength conversion member 40. That is, when the volume Vb of the transparent binder and the volume Vf of the first phosphor particles are used, the ratio is expressed by Vb / (Vf + Vb).

That is, when these ratios are converted into the ratio Vf / (Vf + Vb) of the first phosphor particles 41 to the wavelength conversion member 40, they are 62%, 55%, 45%, and 35%, respectively.

As described above, when the temperature of the fluorophore particles rises, the conversion efficiency of the fluorophore decreases. In particular, when the temperature is 150 ° C. or higher, the conversion efficiency drops sharply. In such a case, the calorific value of the wavelength conversion member 40 rapidly increases, causing quenching in the phosphor conversion, and the light emitting device hardly emits light. For example, when the external environment changes and the temperature of the phosphor particles rises significantly, the light emitting device may not emit light. In the graphs (c) and (e) of FIG. 6, when the thickness of the wavelength conversion member 40 is 35 μm or less, the peak temperature of the surface temperature of the wavelength conversion member 40 is 150 ° C. or less. Therefore, in the light emitting device 101 according to the present embodiment, the thickness of the wavelength conversion member 40 may be 35 μm or less in order for the wavelength conversion element 1 to stably emit high-intensity white light.

On the other hand, regarding the graphs (d) and (f) of FIG. 6, similarly to the graphs (c) and (e) of FIG. 6, the luminosity of the emitted light 95 when the configuration of the wavelength conversion member 40 is changed. It is a figure which showed the chromaticity change.

As mentioned above, the target of the chromaticity coordinates of white light is (0.317, 0.327). Therefore, the target range is a range in which the x value of the chromaticity coordinates is 0.30 or more and 0.35 or less, which is a correlated color temperature close to the white light of the target. Regarding the x value, when the thickness of the wavelength conversion member 40 becomes thin, the x value of the chromaticity coordinates becomes low, and when the thickness becomes thick, the x value becomes high. That is, as the thickness of the wavelength conversion member 40 becomes thinner, the white light becomes more bluish white, and as the thickness becomes thicker, the white light becomes more yellowish. This is because when the thickness of the wavelength conversion member 40 becomes thin, the excitation light 84 is radiated without being sufficiently converted into fluorescence by the wavelength conversion member 40, so that the ratio of the first emitted light 85 to the emitted light 95 becomes This is because the ratio is higher than the ratio of the second emitted light 91. On the other hand, when the thickness of the wavelength conversion member 40 becomes thicker, the excitation light 84 is mostly converted into fluorescence by the wavelength conversion member 40, so that the ratio of the second emitted light 91 out of the emitted light 95 is the first. This is because the ratio is higher than the ratio of the emitted light 85.

The first emitted light 85 emitted from the wavelength conversion member 40 is light emitted by the excitation light 84 being diffusely or multiple-reflected at the interface between the first phosphor particles 41 and the transparent binder 42. Further, a part of the first emitted light 85 includes the excitation light 84 that reaches and is reflected by the reflecting member 3 in the process of diffuse reflection or multiple reflection. As shown in the graphs (d) and (f) of FIG. 6, when the thickness of the wavelength conversion member 40 exceeds 15 μm, the chromaticity x of the chromaticity coordinates of the emitted light 95 increases with respect to the film thickness of the wavelength conversion member 40. The rate will be gradual. It is presumed that this is because the proportion of the excitation light 84 in which the first emitted light 85 does not reach the reflecting member 3 in the process of diffuse reflection or multiple reflection becomes dominant.

On the other hand, when the thickness of the wavelength conversion member 40 is smaller than 15 μm, the chromaticity x of the chromaticity coordinates of the emitted light 95 sharply decreases as the thickness decreases. This is because the excitation light 84 is emitted from the light emitting region 151 with almost no diffuse reflection or multiple reflection inside the wavelength conversion member 40. Therefore, in order to stably adjust the chromaticity coordinates of the emitted light 95, the thickness of the wavelength conversion member 40 may be 15 μm or more.

As described above, the target range is the range in which the x value of the chromaticity coordinates is 0.30 or more and 0.35 or less. In order to realize this target range, the thickness of the wavelength conversion member 40 may be 15 μm or more, as shown in the graphs (d) and (f) of FIG.

From the results of the above examination, the film thickness in the central region 6b of the wavelength conversion member 40 is in the range of 15 μm or more and 35 μm or less from the viewpoint of the surface temperature of the wavelength conversion member 40 and the chromaticity of the emitted light 95. You may. Further, as shown in the graphs (c) to (f) of FIG. 6, when the median diameter D50 of the first phosphor particles 41 is 3 μm or more and 9 μm or less, the film thickness of the wavelength conversion member 40 is 15 μm or more and 35 μm or less. It can be set in the range. Further, the total volume (that is, the volume ratio) of the first phosphor particles 41 can be set to 38% or more and 62% or less with respect to the volume of the wavelength conversion member 40. At this time, in the cross section of the wavelength conversion member 40 as shown in FIG. 3, the total cross-sectional area of the first phosphor particles 41 is about 40% or more and 80% or less with respect to the cross-sectional area of the wavelength conversion member 40.

The effect of the above embodiment will be described with reference to FIG. FIG. 7 is a graph showing the measurement result of the brightness of the emitted light 95 emitted from the wavelength conversion member 40 according to the present embodiment. The graph (a) of FIG. 7 shows the result of measuring the relationship between the drive current applied to the semiconductor light emitting device 110 used for emitting the excitation light 84 and the luminance peak value in the emission region of the emitted light 95. Further, in the graph (a) of FIG. 7, the wavelength conversion member 40 having a film thickness of 42 μm was used together with the result of the light emitting device using the wavelength conversion member 40 having a film thickness of 20 μm according to the present embodiment. The result of the light emitting device of the comparative example is shown. In this measurement, the wavelength conversion element 1 is irradiated with excitation light 84 having a peak wavelength of 446 nm at an ambient temperature (Ta) of 25 ° C. and an optical output of about 3.2 watts at a drive current ( _If ) of 2.3 A. did.

In the light emitting device of the comparative example, the luminance peak value is saturated at a drive current of about 2 amperes. That is, when the drive current is about 2 amperes or more, the luminance peak value hardly increases even if the drive current is increased. As described above, in the light emitting device of the comparative example, when the power of the excitation light 84 increases with the driving current, the surface temperature of the wavelength conversion member 40 and the temperature of the first phosphor particles 41 of the wavelength conversion member 40 are increased. It is considered that this is because the conversion efficiency of the first phosphor particles 41 is sharply lowered. On the other hand, in the wavelength conversion element 1 of the present embodiment, the luminance peak of the emitted light 95 increases with the increase of the driving current even when the driving current is 2 amperes or more, and a light emitting device having a peak luminance exceeding 1000 cd / mm ² can be realized. .. The graph (b) of FIG. 7 shows the luminance distribution in the light emitting region 151 of the wavelength conversion element 1 when the drive current is 2.3 amperes. As shown in the graph (b) of FIG. 7, the width of the light emitting region 151 is about 0.8 mm, and the luminance of the emitted light 95 is 1000 cd / mm ² or more in the high luminance region of the luminance distribution. Moreover, a luminance of 1000 cd / mm ² or more and a flat region can be obtained in a width of 0.2 mm or more. That is, it was possible to realize a light emitting device having a flat brightness distribution and a high brightness light emitting region 151.

Subsequently, a morphological example of the surface shape of the wavelength conversion element 1 will be described in detail with reference to FIG. FIG. 8 is a graph showing the measurement results of each surface shape when the wavelength conversion member 40 of the wavelength conversion element 1 according to the first embodiment is manufactured by three different methods. In the graph (a1) of FIG. 8, the opening of the screen mesh printing mask is a circular opening with a diameter of 2.6 mm, the thickness is 62 μm, and the volume ratio between the first phosphor particles 41 and the transparent binder 42 is 60%. : It is a print of a fluorescent material paste having a ratio of 40%. In the graph (b1) of FIG. 8, the opening of the screen mesh printing mask is a circular opening with a diameter of 2.6 mm, the thickness is 41 μm, and the volume ratio between the first phosphor particles 41 and the transparent binder 42 is 60%. : 40% fluorescent paste is printed. In the graph (C1) of FIG. 8, the opening of the screen mesh printing mask is a rectangular opening with a width of 3.4 mm, the thickness is 62 μm, and the volume ratio of the first phosphor particles 41 and the transparent binder 42 is 40%. : Printed as 60%. The graphs (a2), (b2) and (c2) of FIG. 8 are graphs traced by adding scales to indicate the sizes of the graphs (a1), (b1) and (c1), respectively.

The mesh used here may be, for example, a mesh formed of a material that does not contain Fe. When printing with a mesh made of a material containing Fe, fine powder of Fe is mixed in the wavelength conversion member, and a part of the first emitted light or the second emitted light is absorbed and the efficiency is lowered. By using a mesh made of a material that does not contain Fe, the above-mentioned decrease in efficiency can be suppressed.

In the results shown in the graphs (a1) and (a2) of FIG. 8, the film thickness of the central region of the wavelength conversion member 40 is 44 μm, and the wavelength conversion member 40 has a convex shape in which the central region is thicker than the peripheral region. In this case, as described above, the change in the film thickness of the wavelength conversion member 40 in the vicinity of the light emitting region is small, but the temperature of the wavelength conversion member 40 rises due to the thick film thickness, and it is difficult to increase the brightness of the light emitting device.

In the results shown in the graphs (b1) and (b2) of FIG. 8, the wavelength conversion member 40 has a film thickness of about 20 μm or more and 24 μm or less in the central region, and can suppress the temperature rise of the wavelength conversion member 40. However, since the film thickness may change in the range of 20 μm to 24 μm in the light emitting region, uneven chromaticity in the light emitting region of the emitted light may occur.

On the other hand, in the results shown in the graphs (c1) and (c2) of FIG. 8, the film thickness of the central region of the wavelength conversion member 40 is 18 μm, and the film thickness of the peripheral region is 24 μm. As described above, the wavelength conversion member 40 has a concave shape. Therefore, the film thickness in the central region of the wavelength conversion member 40 can be set to 35 μm or less, and the change in the film thickness in the central region can be suppressed. Therefore, by suppressing the temperature rise of the wavelength conversion member 40 in the light emitting region, the excitation light can be sufficiently converted into fluorescence, and the chromaticity unevenness of the emitted light in the light emitting region can be suppressed.

Further, in the present embodiment, in the wavelength conversion element 1 in which the wavelength conversion member 40 is fixed on the support member 2, the linear expansion coefficients of the support member 2 and the wavelength conversion member 40 are different. In such a case, the thicker the film thickness of the wavelength conversion member 40, the more the stress applied to the wavelength conversion member 40 due to the temperature change of the wavelength conversion element 1 is relaxed, and the more the wavelength conversion member 40 is prevented from peeling off from the support member. be able to. In the graphs (b1), (b2), (c1) and (c2) of FIG. 8, the film thickness of the wavelength conversion member 40 is thick around the central region which radiates fluorescence and the film thickness of the wavelength conversion member 40 is thin. A peripheral part is provided. Therefore, it is possible to suppress peeling of the wavelength conversion member 40 from the support member 2 in response to a change in the environmental temperature of the wavelength conversion element 1 or a temperature change when the wavelength conversion element 1 is made to emit light. That is, in the wavelength conversion element 1 according to the present embodiment, the mechanical strength can be increased. Further, by increasing the film thickness of the peripheral region 6a, it is possible to increase the heat dissipation efficiency from the central region 6b, which has a relatively high temperature, to the peripheral region 6a.

Therefore, as the shape of the wavelength conversion member 40, a concave shape having a thin film thickness in the central region as shown in the graphs (c1) and (c2) of FIG. 8 is optimal. Further, in the wavelength conversion element 1 shown in the graphs (c1) and (c2) of FIG. 8, the film thickness of the wavelength conversion member 40 including the peripheral region is 35 μm or less. Therefore, no matter where the excitation light 84 is irradiated on the wavelength conversion member 40, the temperature rise of the wavelength conversion member 40 can be suppressed. Therefore, even if the excitation light 84 is irradiated to a place other than the central region of the wavelength conversion member 40 when adjusting the position of the excitation region to be irradiated with the excitation light 84 at the time of manufacturing the light emitting device, the wavelength conversion member Deterioration due to the temperature rise of 40 can be suppressed.

The wavelength conversion member 40 as shown in the graphs (c1) and (c2) of FIG. 8 appropriately adjusts the volume ratio between the first phosphor particles 41 and the transparent binder 42 according to the dimensions of the wavelength conversion member and the like. It can be achieved by adjusting. Further, the scanning direction of the squeegee in the fluorescent paste printing process also affects the shape of the wavelength conversion member 40. For example, in the wavelength conversion member 40 shown in the graphs (b1) and (b2) of FIG. 8, the squeegee is scanned from the left side to the right side in the figure in the fluorescent paste printing step of forming the wavelength conversion member 40. Therefore, it is considered that the film thickness at the right end of the wavelength conversion member 40 is the thickest due to the increase in the amount of the phosphor paste at the end of the print mask opening on the scanning end point side of the fluorescent paste printing process.

(Modification 1 of Embodiment 1)
Subsequently, the wavelength conversion element according to the first modification of the first embodiment will be described with reference to the drawings. FIG. 9 is a schematic cross-sectional view showing the configuration of the wavelength conversion element 1B according to this modification.

In the wavelength conversion element 1B according to the present modification, the film thickness dc of the central region 6b of the wavelength conversion member _40B is in the range of 15 μm or more and 35 μm or less as in the first embodiment. On the other hand, in this modification, only a part of the film thickness of the peripheral region 6a of the wavelength conversion member 40B is thicker than the film thickness of the central region 6b. Specifically, in FIG. 9, the maximum film thickness _de2 of the right peripheral region 6a shown in _FIG . 9 is larger than the film thickness dc of the central region ( _de2 > _dc ), and the maximum of the left peripheral region 6a. The film thickness is about the same as the film thickness _dc of the central region 6b.

With this configuration, when the wavelength conversion element 1B is fixed to the storage portion 50a of the light emitting device 101 as shown in FIG. 5 and the light-shielding cover 51 is arranged, the light-shielding cover 51 is the central region 6b (or flat) of the wavelength conversion member 40. It is possible to suppress contact with the portion F1).

As shown in the graphs (b1) and (b2) of FIG. 8, the wavelength conversion element 1B having such a configuration can be manufactured by adjusting the shape of the screen mesh printing mask and the scanning conditions of the squeegee. ..

(Modification 2 of Embodiment 1)
Subsequently, the wavelength conversion element, the light emitting device, and the lighting device according to the second modification of the first embodiment will be described with reference to the drawings. The wavelength conversion element, the light emitting device, and the lighting device according to this modification have different configurations from the wavelength conversion element 1, the light emitting device 101, and the lighting device 201 shown in FIG. 4, respectively. FIG. 10 is a schematic diagram illustrating the configuration of the light emitting device 101B and the lighting device 201B according to the present modification. FIG. 11 is a top view showing the configuration of the wavelength conversion element 1C of this modification.

The lighting device 201B mainly projects a light emitting device 101B that emits emitted light 95, which is white light, a light projecting member 220, dichroic mirrors 314B and 314R, and three image display elements 350B, 350G and 350R. It is equipped with a lens 365. The illuminating device 201B further includes reflection mirrors 331R, 332R, 331B and 332B, and a dichroic prism 360.

The light projecting member 220 converts the emitted light 95 into the projected light 96 which is parallel light. The dichroic mirror 314B is a mirror that reflects only blue light among projected light 96 that is white light and transmits green light and red light. The dichroic mirror 314B is a mirror that reflects only the red light among the green light and the red light transmitted through the dichroic mirror 314B and transmits the green light.

The image display elements 350B, 350G, and 350R are optical elements that superimpose blue, green, and red video information, respectively. In the present embodiment, each image display element includes a liquid crystal panel element.

The reflection mirrors 331R and 332R are mirrors that reflect red light. The reflection mirrors 331B and 332B are mirrors that reflect blue light. The dichroic prism 360 is an optical element that combines and outputs incident blue light, green light, and red light.

The projection lens 365 is a lens that projects synthetic light 385 incident from the dichroic prism 360.

The light emitting device 101B mainly includes a light source unit 320, a condensing optical member 120, and a wavelength conversion element 1C. The light source unit 320 includes a heat sink 325 and a plurality of excitation light sources arranged on the heat sink. In this modification, the light source unit 320 includes, for example, three semiconductor light emitting devices 110 as a plurality of excitation light sources, as shown in FIG. Each of the three semiconductor light emitting devices 110 is, for example, a nitride semiconductor laser device having an optical output of 4 watts and a central wavelength of emission wavelength in the vicinity of 445 nm. Further, the semiconductor light emitting device 110 is a device in which a nitride semiconductor laser element is mounted on a TO-CAN package. The semiconductor light emitting device 110 further includes a lens 120a which is a collimating lens fixed to the TO-CAN package.

The emitted light emitted from the nitride semiconductor laser element of the semiconductor light emitting device 110 becomes collimated light by the lens 120a and is incident on the condenser lens 120c. Then, the excitation light 84 having a total light output of 12 watts collected by the condenser lens 120c heads toward the wavelength conversion element 1C. As described above, the condensing optical member 120 is composed of the lens 120a and the condensing lens 120c.

The wavelength conversion element 1C is a phosphor wheel in this modification, and has, for example, a disc-shaped support member 2 made of an aluminum alloy plate, as shown in FIG. 11. Then, the wavelength conversion member 40C is formed in a ring shape in the outer peripheral region of the support surface 2a of the support member 2.

In the wavelength conversion member 40C, for example, first phosphor particles made of a Ce-activated Y3 ₍ Al, Ga) _{5O 12} phosphor are mixed and fixed to a transparent binder 42 such as silsesquioxane. The wavelength conversion element 1C shown in FIG. 10 shows a cross section of the wavelength conversion element 1C in the XX rays of FIG.

At this time, the thickness of the wavelength conversion member 40C of the wavelength conversion element 1C is configured to be 15 μm or more and 35 μm or less in the excitation region 150 irradiated with the excitation light 84 as shown in the first embodiment. The maximum film thickness in the peripheral region of the wavelength conversion member 40C is thicker than the film thickness in the central region. Here, the peripheral region of the wavelength conversion member 40C includes a ring-shaped region including the inner peripheral edge 40i of the ring-shaped wavelength conversion member 40C shown in FIG. 11 and a ring-shaped region including the outer peripheral edge 40e. The central region is a region between the peripheral region including the inner peripheral edge 40i and the peripheral region including the outer peripheral edge 40e.

In this modification as well, the wavelength conversion member 40C may have a structure in which the film thickness of the entire region is in the range of 15 μm or more and 35 μm or less, and the central region of the wavelength conversion member 40C is thinner than the peripheral region.

The rotation shaft 191 of the rotation mechanism 190 is connected to the center of the support member 2 of the wavelength conversion element 1C having such a configuration. During the operation of the light emitting device 101B, the wavelength conversion element 1C rotates with the rotation of the rotation mechanism 190. Then, the excitation light 84 is focused on the excitation region 150 of the wavelength conversion member 40C by the condenser lens 120c. At this time, the excitation light 84 focused on the wavelength conversion member 40C is the first emission light 85, which is the excitation light 84 scattered by the first phosphor particles 41 and the transparent coupling material 42 contained in the wavelength conversion member 40C. The second emitted light 91, which is the fluorescence wavelength-converted by the first phosphor particles 41, is emitted from the light emitting device 101B as the emitted light 95, which is the mixed white light.

In this configuration, the wavelength conversion element 1C prevents the rotation mechanism 190 from continuously irradiating the excitation light 84 at a specific position of the wavelength conversion member 40C. As a result, even when the wavelength conversion member 40C irradiates the strong excitation light 84, the temperature rise in the light emitting region can be suppressed, so that the emitted light 95 with higher brightness can be emitted.

The emitted light 95 becomes projected light 96 which is parallel light by the light projecting member 220 which is a condensing lens, and is converted into projected light 389 which is image light by the following operation inside the lighting device 201B. First, the projected light 96 is a dichroic mirror 314B, and is separated into blue light 379B having a main wavelength band of 430 nm or more and 500 nm or less and yellow light 379Y which is the remaining light. The blue light 379B is reflected by the reflection mirrors 331B and 332B, passes through a polarizing element (not shown), becomes polarized, and is incident on the image display element 350B. On the other hand, the yellow light 379Y is separated into green light 379G having a main wavelength band of 500 nm or more and 580 nm or less and red light 379R having a main wavelength band of 580 nm or more and 660 nm or less by the dichroic mirror 314R. The red light 379R is reflected by the reflection mirrors 331R and 332R, and when it passes through a polarizing element (not shown), it becomes polarized and is incident on the image display element 350R. The green light 379G is polarized by passing through a polarizing element (not shown) and is incident on the image display element 350G. The blue light 379B, green light 379G, and red light 379R incident on the image display elements 350B, 350G, and 350R are signal lights on which video information is superimposed by each image display element and a polarizing element (not shown) on the emitting side thereof. It becomes 380B, 380G and 380R. The signal lights 380B, 380G and 380R are irradiated to the dichroic prism 360 and combined to form synthetic light 385. By passing the combined light 385 through a projection lens, projected light 389, which is image light, can be obtained.

In the above configuration, the excitation light 84 emitted from the semiconductor light emitting device 110 and irradiating the wavelength conversion member 40C has a light output of 10 W or more, and irradiates a region having an area of 1 mm ² or less in the excitation region 150. At this time, the light density of the excitation light in the excitation region 150 is set so that the light density peak is at least 17 W / mm ² or more. Here, the film thickness of the wavelength conversion member 40C in the light emitting region 151 is in the range of 15 μm or more and 35 μm or less. As described above, according to such a wavelength conversion member 40C, the excitation light 84 can be converted into the emitted light 95 while suppressing the temperature rise, so that the conversion can be performed, for example, with a conversion efficiency of 200 lm / W. Therefore, it is possible to easily realize a light emitting device that emits emitted light 95 having a luminance peak of 1000 cd / mm ² or more.

As described above, in a light emitting device that converts light emitted from a semiconductor light emitting device such as a semiconductor laser device by using a phosphor and radiates it, the saturation of the conversion efficiency in the phosphor is suppressed and the light emitting device has high brightness. Can be provided.

(Embodiment 2)
Subsequently, the wavelength conversion element according to the second embodiment will be described. The wavelength conversion element according to the present embodiment is different from the wavelength conversion element 1 according to the first embodiment in that the wavelength conversion member contains scattered particles other than the first phosphor particles. Hereinafter, the wavelength conversion element according to the present embodiment will be described with reference to the drawings, focusing on the differences from the wavelength conversion element 1 according to the first embodiment.

FIG. 12 is a schematic cross-sectional view showing the configuration of the wavelength conversion element 1D according to the present embodiment. The wavelength conversion member 40D of the wavelength conversion element 1D according to the present embodiment includes, in addition to the first phosphor particles 41 and the transparent binder 42, a plurality of scattered particles that bind to the transparent binder 42.

In the wavelength conversion member 40D, as the first phosphor particles 41, the median diameter D50 is 2 μm or more and 30 μm or less, for example, (Y _x Gd _1-x ) ₃ (Al _y Ga _1-y ) ₅ O ₁₂ : Ce (0. Fluorescent materials such as 5 ≦ x ≦ 1 and 0.5 ≦ y ≦ 1) are used. As the transparent binder 42 for binding the first phosphor particles 41, for example, a transparent material such as dimethyl silicone, silsesquioxane, or low melting point glass can be used. As the silsesquioxane, for example, polymethylsilsesquioxane or the like can be used. Further, as the scattered particles 43, non-luminescent particles having a median diameter D50 of 0.3 μm or more and 18 μm or less and made of a material having little absorption to excitation light and fluorescence are mixed.

As the scattered particles 43, for example, a transparent material having a high thermal conductivity and a large difference in refractive index from the transparent binder 42 is used. Scattered particles may include metal oxides or nitrides. Specifically, the scattered particles 43 are formed of Al ₂ O ₃ , TIO ₂ , ZrO ₂ , ZnO, BN and the like. The volume ratio of the scattered particles 43 to the first phosphor particles 41 is, for example, 10 vol% or more and 90 vol% or less.

Regarding the film thickness of the wavelength conversion member 40D, as in the first embodiment, the film thickness _{d c} in the central region is thinner than the maximum film thickness de in the peripheral region, and the wavelength conversion member 40D has a film thickness of 15 μm in the entire region. It is in the range of 35 μm or less.

Further, a void 45 may be provided inside the wavelength conversion member 40D. In the present embodiment, the void 45 is formed inside the wavelength conversion member 40D and near the interface between the wavelength conversion member 40D and the reflection member 3.

In the wavelength conversion element 1D configured as described above, the chromaticity coordinates of the emitted light 95 can be freely designed according to the spectrum of the excitation light 84. Specifically, by changing the ratio of the first phosphor particles 41 and the scattered particles 43 of the wavelength conversion member 40D according to the spectrum of the excitation light 84, the chromaticity of each light emitting device using the wavelength conversion element 1D is changed. The coordinates can be adjusted. That is, even if the spectrum of the excitation light 84 varies depending on the semiconductor light emitting device due to the structural variation of the semiconductor light emitting device that emits the excitation light 84, the scattering contained in the first phosphor particles 41 according to the spectrum of the excitation light 84. The chromaticity coordinates can be adjusted by adjusting the proportion of particles. Hereinafter, the wavelength conversion element 1D of the present embodiment will be described in detail with reference to FIGS. 12 to 16.

In the wavelength conversion member 40D of the wavelength conversion element 1D according to the present embodiment, a Y3 Al ₅ O ₁₂ : Ce phosphor having a median diameter D50 of ₆ μm is used as the first phosphor particles 41. Then, polymethylsilsesquioxane is used as the transparent binder 42 for fixing the first phosphor particles 41. As the scattered particles 43 which are non-emission particles, Al ₂ O ₃ particles having a median diameter D50 of 3 μm are mixed. The refractive index of Al ₂ O ₃ is 1.77, and the difference in refractive index from silsesquioxane having a refractive index of 1.5 is large. Further, the thermal conductivity of Al ₂ O ₃ is as high as 30 W / mK. With this configuration, it is possible to improve the light scattering property inside the wavelength conversion member 40D and to increase the thermal conductivity of the wavelength conversion member 40D.

In the present embodiment, a void 45 may be further formed inside the wavelength conversion member 40D. Such a void 45 is used when the first fluorescent particle 41 made of Y ₃ Al ₅ O ₁₂ : Ce and the transparent binder 42 made of polysilsesquioxane are mixed to form a fluorescent paste. It can be easily constructed by reducing the ratio of the transparent binder 42 and curing it at a high temperature as compared with the first phosphor particles 41 and the scattered particles 43.

Specifically, the ratio of the volume Vb of the transparent binder 42, which is silsesquioxane, to the total volume (Vf + Vs) of the volume Vf of the first phosphor particles 41 and the volume Vs of the scattered particles 43 Vb / (Vf + Vs). Is 40% or less. Then, a phosphor paste composed of a mixture of the transparent binder 42 dissolved in an organic solvent, the first phosphor particles 41, and the scattered particles 43 is formed on the support member 2, and then annealed at a high temperature of about 200 ° C. This vaporizes the organic solvent in the paste.

The cross-sectional structure of the wavelength conversion element 1D produced by the above method will be described with reference to FIG. FIG. 13 is a photograph of a cross section of the wavelength conversion element 1D according to the present embodiment observed with a scanning electron microscope. FIG. 3 shows a cross-sectional photograph (a) and an enlarged photograph (b) in which a part thereof is enlarged. The enlarged photograph (b) is an enlarged photograph of the broken line frame portion of the cross-sectional photograph (a).

As shown in FIG. 13, a reflective member 3 is formed on a support member 2 which is a silicon substrate, and a wavelength conversion member 40D is fixed on the reflective member 3. The film thickness of the wavelength conversion member 40D is 24 μm, and inside the wavelength conversion member 40D, the first phosphor particles 41 and the scattered particles 43 are dispersed in the transparent binder 42. Further, voids 45 are scattered inside the wavelength conversion member 40D and at the interface with the reflection member 3. As described above, by the manufacturing method of the present embodiment, the wavelength conversion member 40D in which the first phosphor particles 41 and the scattered particles 43 are dispersed inside the transparent binder 42 and the voids 45 are interspersed can be easily obtained. realizable.

According to the wavelength conversion element 1D, the excitation light 84 that has entered the inside of the wavelength conversion member 40D can be more efficiently scattered and taken out from the wavelength conversion member 40D. Further, since a part of the void 45 is in contact with the second reflective film 3c of the reflective member 3 which is a dielectric, the excitation light is effectively reduced while reducing the energy loss due to the excitation light and the fluorescence incident on the metal surface. , Fluorescence can be scattered.

Further, the wavelength conversion member 40D of the present embodiment includes scattered particles 43 which are non-light emitting particles. By changing the volume ratio of the scattered particles 43 in the wavelength conversion member 40D, the chromaticity coordinates of the emitted light 95 can be easily adjusted.

Since the semiconductor light emitting device, which is a semiconductor laser device composed of a nitride semiconductor, has a slight individual difference in the wavelength of the emitted light, the light emitting device using the semiconductor light emitting device has an individual difference in the chromaticity of the emitted light. Can occur. Therefore, in the wavelength conversion member 40D in which the scattered particles 43 are mixed, the method of adjusting the chromaticity of the emitted light by changing the ratio of the first phosphor particles 41 and the scattered particles 43 is described with reference to FIGS. 14 and 15. explain.

FIG. 14 is a graph showing the spectrum of the emitted light 95 when the wavelength conversion element 1D according to the present embodiment is irradiated with the excitation light 84 having a peak wavelength of 447 nm. It is composed of a first emitted light 85 having a sharp peak at a wavelength of 447 nm and a second emitted light 91 having a broad peak having a wavelength of 500 nm to 700 nm. In FIG. 14, in order to show the spectral characteristics of the second emitted light 91, a spectrum 10 times the intensity of the second emitted light 91 is shown by a broken line.

FIG. 15 is a graph showing changes in the chromaticity coordinates of the emitted light 95 when the ratio of the first phosphor particles 41 and the scattered particles 43 is changed in the wavelength conversion element 1 according to the present embodiment. .. At this time, YAG: Ce phosphor particles having a median diameter D50 of 6 μm were used as the first phosphor particles 41, and Al ₂ O ₃ particles having a median diameter D50 of 3 μm were used as the scattered particles. As the transparent binder 42, silsesquioxane was used. Further, the ratio Vb / (Vf + Vs + Vb) of the volume Vb of the transparent binder 42 to the sum of the volume Vf of the first phosphor particles 41, the volume Vs of the scattered particles 43, and the volume Vb of the transparent binder 42 was set to 35%. .. The six types of wavelength conversion elements 1D in which the volume ratios Vf / (Vf + Vs) of the first phosphor particles 41 and the scattered particles 43 are 76%, 73%, 69%, 65%, 61%, and 51%, respectively. Was produced. Then, a laser beam having a peak wavelength of 447 nm was used as the excitation light 84 to irradiate each wavelength conversion element 1D, and the chromaticity coordinates of the emitted light 95 were plotted in FIG. The solid line shown in FIG. 15 shows the locus of blackbody radiation.

As a result, by increasing the ratio of the first phosphor particles 41, the chromaticity coordinates x and y can be increased, that is, the white light close to yellow can be shifted. Further, by increasing the number of scattered particles 43, the chromaticity coordinates x and y can be reduced, that is, the white light close to blue can be shifted. Now, when the chromaticity coordinates (0.317, 0.327) are used as the target of the chromaticity coordinates, the volume ratio of the first phosphor particles 41 and the scattered particles 43 is set to 61% to obtain the desired chromaticity coordinates. Emitted light can be obtained. Therefore, the chromaticity coordinates of the emitted light can be easily set to the predetermined chromaticity coordinates by changing the volume ratio of the first phosphor particles 41 and the scattered particles 43.

Further, in the wavelength conversion element 1D of the present embodiment, the chromaticity coordinates of the light emitted from the light emitting device can be adjusted by adjusting the structure according to the peak wavelength of the excitation light 84. This adjustment method will be described with reference to FIG.

FIG. 16 is a graph showing the results of measuring the peak wavelength dependence of the excitation light of the chromaticity coordinates of the emitted light 95 in the wavelength conversion element 1D according to the present embodiment. At this time, the wavelength conversion element 1D has the same volume ratio Vf / (Vf + Vs) of the first phosphor particles 41 and the scattered particles 43 as that shown in FIG. 15, which is 76%, 73%, 69%, 65%, 61%. , 51%, and the change in chromaticity coordinate y was plotted using the excitation light 84 having a peak wavelength of 438 nm, 441 nm, 444 nm, 447 nm, and 451 nm.

As shown in FIG. 16, for example, when the chromaticity y of the chromaticity coordinates is targeted at 0.327, the ratio of the scattered particles 43 is changed even if the peak wavelength of the excitation light changes from about 440 nm to about 447 nm. By changing the color, the chromaticity coordinate of the emitted light can be set to a predetermined chromaticity coordinate.

Further, in the present embodiment, the effect of scattering light can be enhanced by increasing the difference in refractive index between the transparent binder and the first phosphor particles and the scattered particles. This makes it possible to suppress the propagation of light inside the wavelength conversion member 40D. As a result, the emitted light 95 can be emitted from the light emitting region 151 having substantially the same area as the excited region 150. In the present embodiment, the void 45 is further formed in the wavelength conversion member 40D to enhance the light scattering. As a result, the area of the light emitting region 151 can be further brought closer to the area of the excited region 150.

In the present embodiment, similarly to the first embodiment, in the luminance distribution of the emitted light 95 on the radiation surface 6, a light emitting region 151 having a luminance of 200 cd / mm ² or more exists over a width of about 0.7 mm. That is, the same light emitting region 151 as the excited region 150 can be realized. Then, in the vicinity of the peak, a uniform region can be realized with a luminance of 1000 cd / mm ² or more and a width of 0.2 mm or more.

(Embodiment 3)
Subsequently, the wavelength conversion element and the light emitting device according to the third embodiment will be described. The wavelength conversion element and the light emitting device according to the present embodiment are different from the first and second embodiments in the material constituting the wavelength conversion member, and are the same in other respects. Hereinafter, the wavelength conversion element and the light emitting device according to the present embodiment will be described with reference to the drawings, focusing on the differences from the first and second embodiments.

In the present embodiment, as the material constituting the first phosphor particles 41 included in the wavelength conversion member 40, (La _x Y _1-x ) ₃ Si ₆ N ₁₁ : Ce (0.5 ≦ x ≦ 1) A fluorescent material represented by is used. FIG. 17 is a diagram showing the refractive index and thermal conductivity of the material that can form the wavelength conversion member 40. Note that FIG. 17 shows the refractive index for light having a wavelength of 550 nm. Among the materials shown in FIG. 17, as the phosphor material, a phosphor that absorbs blue light having a wavelength of 430 nm or more and 470 nm or less and emits yellow fluorescence having a wavelength range of 520 nm or more and 650 nm or less was examined. Specifically, (Y _x Gd _1-x ) ₃ (Al _y Ga _1-y ) ₅ O ₁₂ : With the phosphor represented by Ce (0.5 ≦ x ≦ 1, 0.5 ≦ y ≦ 1). , (La _x Y _1-x ) ₃ Si ₆ N ₁₁ : The phosphor represented by Ce (0.5 ≦ x ≦ 1) and (Ba _x Sr _1-x ) SiO ₄ : Eu (0 ≦ x ≦ 1). ) Was compared with the fluorophore represented by (Ba _x Sr _1-x ) Si ₂ O ₂ N ₂ : Eu (0 ≦ x ≦ 1). Of these phosphors, FIG. 17 shows (Y _x Gd _1-x ) ₃ (Al _y Ga _1-y ) ₅ O ₁₂ : Ce (0.5 ≦ x ≦ 1, 0.5 ≦ y ≦ 1). Y ₃ Al ₅ O ₁₂ , which is the central base material of the fluorescent material represented by, and (La _x Y _1-x ) ₃ Si ₆ N ₁₁ : The fluorescent material represented by Ce (0.5 ≦ x ≦ 1). La ₃ Si ₆ N ₁₁ which is the central base material of the above is shown. As the material used as the scattered particles 43, Al ₂ O ₃ , TiO ₂ , ZnO and BN are shown. As the material used as the transparent binder 42, silsesquioxane, dimethylsilicone and low melting point glass are shown. The material constituting the wavelength conversion member may be a material having high thermal conductivity. Further, in order to suppress the excitation light incident on the wavelength conversion member 40 from propagating laterally in the wavelength conversion member 40, the difference in refractive index between the phosphor particles and the transparent binder, and the scattered particles and the transparent binder The difference in refractive index from and may be large. From this point of view, the phosphor material may be either Y ₃ Al ₅ O ₁₂ : Ce fluorescent substance or La ₃ Si ₆ N ₁₁ : Ce fluorescent substance. The scattered particles may be any of Al ₂ O ₃ , ZnO, and BN.

Hereinafter, the characteristics of the wavelength conversion member according to the present embodiment will be described with reference to FIGS. 18 and 19. FIG. 18 shows the temperature of the quantum efficiency of the La ₃ Si ₆ N ₁₁ : Ce phosphor used in the wavelength conversion member according to the present embodiment and the Y ₃ Al ₅ O ₁₂ : Ce phosphor used in the first embodiment. It is a figure which shows the dependency. The quantum efficiency shown in FIG. 18 is the efficiency of irradiating a phosphor with an excitation wavelength having a wavelength of 450 nm and converting it into fluorescence. Note that FIG. 18 shows the relative values of the quantum efficiency when the quantum efficiency is 100% when the environmental temperature (Ta) is 25 ° C. Compared with Y ₃ Al ₅ O ₁₂ : Ce phosphor, La ₃ Si ₆ N ₁₁ : Ce has a smaller rate of decrease in quantum efficiency at higher temperatures. Therefore, La _{3Si 6 N 11} : Ce used in the wavelength conversion member according to the present embodiment is more suitable as a material constituting the wavelength conversion member of the light emitting device having a high light density of the excitation light.

FIG. 19 is a diagram showing the characteristics of a light emitting device equipped with a wavelength conversion element according to the present embodiment. In the wavelength conversion element according to the present embodiment, (La _0.84 Y _0.16 ) ₃ Si ₆ N ₁₁ : Ce having a median diameter D50 of 9 μm is used as the first phosphor particles 41, and the median diameter D50 is 3 μm. Al ₂ O ₃ particles were used as the scattered particles 43. A wavelength conversion member 40 in which these first phosphor particles 41 and scattered particles 43 were dispersed in a transparent binder 42 whose main component was silsesquioxane was used. The composition ratio of the first phosphor particles, the scattered particles, and the transparent binder is a volume ratio in the step of constituting the wavelength conversion member, and the ratio of the first phosphor particles: the scattered particles: the transparent binder is 18%: 22. %: It was set to be 60%. Further, as the configuration of the wavelength conversion element 1 and the light emitting device 101 used for measuring the characteristics, the same configuration as that of the first embodiment shown in FIGS. 4 and 5 was used. The film thickness of the wavelength conversion member 40 of the wavelength conversion element 1 was about 25 μm in the vicinity of the light emitting region 151.

FIG. 19 is a graph in which the peak value of the brightness of the light emitting region 151 of the wavelength conversion member with respect to the current applied to the semiconductor light emitting device 110 in the above-mentioned light emitting device 101 is plotted. At this time, the environmental temperature (Ta) of the light emitting device 101 was set to 85 ° C.

In FIG. 19, a light emitting device of a comparative example using a YAG: Ce phosphor as the first phosphor particles shown in FIG. 7 and a wavelength conversion member having a film thickness of 42 μm is operated at an ambient temperature (Ta) of 85 ° C. The characteristics when it is made to do so are also shown. Similarly, the characteristics when the light emitting device according to the first embodiment using the wavelength conversion member 40 having a film thickness of 20 μm and using a YAG: Ce phosphor as the first phosphor particles is operated at an environmental temperature of 85 ° C. are also included. It is shown. In the light emitting device of the first embodiment as compared with the comparative example, even if the drive current is 2 A or more, the rate of increase in luminance with respect to the increase in drive current is high and the peak value of luminance reaches 800 cd / mm ² or more. However, even if the drive current was further increased, the rate of increase in luminance decreased, and saturation was achieved at less than 900 cd / mm ² . This is because the temperature of the wavelength conversion member 40 rises due to the heat received from the environment by the wavelength conversion member 40 and the heat generated when the excitation light 84 is converted into the second emitted light 91, so that the quantum efficiency rapidly increases. It is thought that it will decrease. On the other hand, in the wavelength conversion element according to the present embodiment, as the first phosphor particles, the decrease in quantum efficiency is small with respect to the temperature rise (La _x Y _1-x ) ₃ Si ₆ N ₁₁ : Ce (0). ≦ x ≦ 1) A phosphor is used. Therefore, the ambient temperature reached 85 ° C. and a drive current of 2 amperes reached 800 cd / mm ² or more, and even at a drive current higher than that, the luminance was not saturated and reached 900 cd / mm ² or more at a drive current of 2.3 amperes. FIG. 20 is a graph showing the results of measuring the luminance distribution of the light emitting region 151 on the surface of the phosphor when the drive current of the semiconductor light emitting device 110 of the light emitting device 101 is 2.3 amperes in the luminance measurement of FIG. be. In FIG. 20, the luminance distribution when the environmental temperature is 25 ° C. is also shown by the dotted line. As shown in FIG. 20, the luminance distribution at an environmental temperature of 85 ° C. is about 20% lower than the luminance distribution at an environmental temperature of 25 ° C. This is mainly due to the temperature dependence of the semiconductor light emitting device, not the decrease in the quantum efficiency of the wavelength conversion element. Therefore, it is possible to further increase the brightness by appropriately controlling the temperature of the semiconductor light emitting device. ..

As described above, in the present embodiment, it is possible to realize a light emitting device capable of high-luminance operation with a peak brightness of 900 cd / mm ² or more even when the environmental temperature is 85 ° C. Such a light emitting device is most suitable for a lighting device that requires high temperature operation, for example, a headlight of a vehicle.

(Embodiment 4)
Subsequently, the wavelength conversion element according to the fourth embodiment will be described. In a conventional light emitting device such as the light emitting device described in Patent Document 1, the chromaticity coordinates of the emitted light are regulated by the type of the phosphor contained in the phosphor layer, so that the chromaticity coordinates of the emitted light are adjusted. Difficult to do. Therefore, in the present embodiment, a wavelength conversion element and a light emitting device capable of increasing the degree of freedom in adjusting the chromaticity coordinates of the emitted light will be described.

The wavelength conversion element according to the present embodiment is different from the wavelength conversion element according to the third embodiment in that the wavelength conversion member includes the second phosphor particles in addition to the first phosphor particles, and other points. Matches in. Hereinafter, the wavelength conversion element according to the present embodiment will be described with reference to FIGS. 21 to 23.

FIG. 21 is a schematic cross-sectional view showing the configuration of the wavelength conversion element 1F according to the present embodiment. As shown in FIG. 21, the wavelength conversion element 1F according to the present embodiment includes a support member 2 having a support surface 2a and a wavelength conversion member 40F arranged above the support surface 2a, and is a wavelength conversion member 40F. Includes a plurality of first fluorescence particles 41 that generate the first fluorescence, and a plurality of second phosphor particles 44 that generate the second fluorescence having a spectrum different from that of the first fluorescence. The wavelength conversion member 40F further combines a transparent binder 42 that binds the plurality of first phosphor particles 41 and the plurality of second phosphor particles 44, and the transparent binder 42, and the plurality of first fluorescences. It contains a body particle 41 and a scattering particle 43 different from the plurality of second phosphor particles 44.

In the present embodiment, both the fluorescent particles of the first fluorescent particle 41 and the second fluorescent particle 44 have the same basic composition formula with a median diameter D50 of 2 μm or more and 30 μm or less (that is, the same). (Has constituent elements) and uses fluorescent material with different composition ratios. Similar to the first phosphor particles 41 according to the first embodiment, the median diameter D50 of the first phosphor particles 41 and the second phosphor particles 44 may be 3 μm or more and 9 μm or less. Specific basic composition formulas representing the first fluorescent particle 41 and the second fluorescent particle 44 are, for example, (La _x Y _1-x ) ₃ Si ₆ N ₁₁ : Ce (0.5 ≦ x ≦ 1). be. That is, the plurality of first phosphor particles 41 include Ce-activated (La _1-x1 , Y _x1 ) ₃ Si ₆ N ₁₁ (0 ≦ x1 ≦ 1), and the plurality of second phosphor particles 44 , Ce activated (La _1-x2 , Y _x2 ) ₃ Si ₆ N ₁₁ (0 ≦ x2 ≦ 1, x1 ≠ x2).

Further, the wavelength conversion member 40F includes scattered particles 43 which are non-emission particles that do not absorb the excitation light. When the median diameter D50 of the scattered particles 43 is closer to the median diameter of each phosphor particle, the scattering efficiency of the scattered particles 43 is higher. Therefore, the median diameter D50 of the scattered particles 43 is set to, for example, 0.3 μm or more and 18 μm or less.

Like the wavelength conversion element 1F according to the present embodiment, the wavelength conversion member 40F includes the first phosphor particles 41, the scattered particles 43, and the second phosphor particles 44 having a composition different from that of the first phosphor particles 41. Disperse. According to such a wavelength conversion member 40F, the chromaticity coordinates of the emitted light can be adjusted more freely by adjusting the mixing ratio of each particle.

Hereinafter, a specific configuration of the wavelength conversion element 1F of the present embodiment will be described. In the present embodiment, in the wavelength conversion member 40F, La 3 Si 6 N 11: Ce having a median diameter of 12 μm is used as the first phosphor particles 41, and La ₃ Si ₆ N ₁₁ : Ce has a median diameter of 9 μm as the second phosphor particles 44 (La). _0.84 Y _0.16 ) ₃ Si ₆ N ₁₁ : Ce was used. Then, as the scattered particles 43, Al ₂ O ₃ having a median diameter D50 of 3 μm was used. As the transparent binder 42 for fixing the first fluorescent particles 41, the second fluorescent particles 44, and the scattered particles 43, a transparent material mainly containing polymethylsilsesquioxane was used.

At this time, the ratio Vf / (Vf + Vf2) of the volume Vf of the first phosphor particles 41 and the volume Vf2 of the second phosphor particles 44 is larger than 0% and smaller than 100%. Further, the ratio Vs / (Vf + Vf2 + Vs) of the volume Vs of the scattered particles 43 to the volume of the phosphor particles is 10% or more and 90% or less.

FIG. 22 is a graph showing the spectral characteristics of the emitted light of the light emitting device using the wavelength conversion element 1F according to the present embodiment. The same basic composition formula (La _x Y _1-x ) ₃ Si ₆ N ₁₁ : Ce (0.5) as the first fluorescent particle 41 and the second fluorescent particle 44 of the wavelength conversion element 1F according to the present embodiment. A phosphor having ≦ x ≦ 1) is used. Therefore, the second emitted light 91, which is fluorescence having substantially the same spectral shape as the spectral shape of each of the first phosphor particles 41 and the second phosphor particles 44, is emitted from the wavelength conversion element 1F. Further, the relationship between the drive current ( _If ) of the semiconductor light emitting device and the brightness was almost the same as the relationship in the light emitting device according to the third embodiment shown by the white circle in FIG.

FIG. 23 is a diagram showing changes in the chromaticity coordinates of the emitted light when the configuration of the wavelength conversion element 1F is changed in the light emitting device equipped with the wavelength conversion element 1F according to the fourth embodiment. In the chromaticity diagram on the left side of FIG. 23, the chromaticity coordinates of the first emitted light 85, which is the scattered light of the excitation light having a peak wavelength of 445 nm, are indicated by reference numeral 85. Further, the chromaticity coordinates of the fluorescence emitted from the first phosphor particles 41 composed of La ₃ Si ₆ N ₁₁ : Ce are indicated by reference numeral 91a. Then, the chromaticity coordinates of the fluorescence emitted from the second phosphor particle 44 composed of (La _0.84 Y _0.16 ) ₃ Si ₆ N ₁₁ : Ce are indicated by reference numeral 91b. Therefore, the emitted light 95 when the wavelength conversion member is composed of the first phosphor particles 41, the scattered particles 43, and the transparent coupling material 42 is plotted at any coordinate on the locus 195a. Further, the emitted light 95 when the wavelength conversion member is composed of the second phosphor particles 44, the scattered particles 43, and the transparent coupling material 42 is plotted at any coordinate on the locus 195b.

The figure on the right side of FIG. 23 is an enlarged view of the vicinity of the chromaticity coordinates (0.33, 0.33) in the chromaticity diagram on the left side.

Here, as the configuration of the wavelength conversion member of the wavelength conversion element, the wavelength conversion elements (a) to (a) to which the volume ratios of the first phosphor particles, the second phosphor particles, the scattered particles and the transparent binder are the following three types. c) was created and shown in the enlarged view on the right side of FIG. 23.

(A) 18: 0: 22: 60
(B) 0:18:22:60
(C) 9: 9: 22: 60

At this time, the film thickness in the light emitting region 151 of the wavelength conversion member was about 25 μm. Further, the chromaticity coordinates of the emitted light 95 were measured by mounting a wavelength conversion element on the light emitting device 101 shown in FIG.

The chromaticity coordinates 95a, 95b, and 95c in the enlarged view on the right side of FIG. 23 are the chromaticity coordinates of the emitted light emitted from the wavelength conversion element corresponding to the above (a), (b), and (c), respectively. In this way, by using phosphors of the same basic color having different composition ratios and changing the mixing ratio, the chromaticity coordinates can be adjusted in a direction other than the locus connecting the excitation light and the fluorescence. That is, by changing the ratio of the three types of particles, the first phosphor particles, the second phosphor particles, and the scattered particles, the chromaticity coordinates on the chromaticity diagram can be freely adjusted in the x-axis and y-axis directions. can. That is, even when a light emitting device is mass-produced, only three types of particles, a first phosphor particle, a second phosphor particle, and a scattered particle, need to be prepared in order to obtain desired chromaticity coordinates.

More specifically, the region A shown in FIG. 23 is a region of the chromaticity of the headlight for a vehicle defined by the Japanese Industrial Standards JIS D 5500. When manufacturing a light emitting device for this purpose, first phosphor particles, second phosphor particles and scattered particles are prepared, and their ratios are adjusted to produce a wavelength conversion member and a wavelength conversion element. Thereby, the chromaticity of the shaded area portion within the chromaticity region defined by the above-mentioned standard can be freely obtained.

Further, the scattered particles 43 included in the wavelength conversion member 40 also have an effect of improving the uniformity of the chromaticity of the emitted light in the light emitting region. That is, the presence of the scattered particles 43 allows the first fluorescence emitted from the first phosphor particles 41 and the second fluorescence emitted from the second phosphor particles 44 to be scattered and mixed. Therefore, the emitted light having a uniform chromaticity can be emitted from the light emitting region of the wavelength conversion member 40.

With the above configuration, it is possible to provide a light emitting device in which the brightness of the emitted light is high, the uniformity of the chromaticity in the light emitting region is high, and the chromaticity can be easily adjusted.

In the wavelength conversion member 40F according to the present embodiment, the median diameter D50 of the first phosphor particles 41 and the second phosphor particles 44 is 2 μm or more and 30 μm or less (La _x Y _1-x ) ₃ Si ₆ N ₁₁ : Although described using Ce (0.5 ≦ x ≦ 1), this is not the case. Depending on the brightness and spectrum of the emitted light required for the light emitting device used, (Y _x Gd _1-x ) ₃ (Al _y Ga _1-y ) ₅ O ₁₂ : Ce (0.5 ≦ x ≦ 1, 0.5 ≦ y ≦ 1) and the like can be used. In this case, a material other than silsesquioxane may be used as the transparent binder. For example, by constructing the transparent binder 42 with a material mainly composed of inorganic substances such as SiO ₂ , Al ₂ O ₃ , ZnO, Ta ₂ O ₅ , Nb ₂ O ₅ , TIO ₂ , AlN, BN, and BaO. It is possible to realize a wavelength conversion element 1 having high reliability. Further, as the scattered particles 43 included in the wavelength conversion member 40F, not only Al ₂ O ₃ but also fine particles such as SiO ₂ , TiO ₂ and Zn O can be used depending on the application of the light emitting device. In particular, by mixing boron nitride (BN) with high thermal conductivity and fine particles of diamond, the light scattering property of the wavelength conversion member 40F is strengthened, and the heat from the phosphor material is efficiently transferred to the support member. Can be done.

(Embodiment 5)
Subsequently, the light emitting device and the lighting device according to the fifth embodiment will be described. In the light emitting device and the lighting device according to the present embodiment, the excitation light is irradiated between the semiconductor light emitting device 110 and the wavelength conversion element 1 while scanning the surface of the wavelength conversion member using a movable mirror unit. However, it is different from the light emitting device 101 and the lighting device 201 according to the first embodiment. Hereinafter, the light emitting device and the lighting device according to the present embodiment will be described with reference to the drawings, focusing on the differences from the light emitting device 101 and the lighting device 201 according to the first embodiment.

FIG. 24A is a schematic cross-sectional view showing the configuration of the lighting device 201C according to the present embodiment.

As shown in FIG. 24A, the lighting device 201C includes a light emitting device 101C, a light projecting member 220, and a fourth base 221. The light emitting device 101C is a light source that emits emitted light 95 from the wavelength conversion element 1. The lighting device 201C converts the emitted light 95 into projected light 96, which is light with strong directivity, by the light projecting member 220 and emits the emitted light 95.

The light emitting device 101C includes a wavelength conversion element 1, a semiconductor light emitting device 110, and a lens 120a, as in the first embodiment. In the present embodiment, the light emitting device 101C includes a movable mirror unit 520 in the optical path between the lens 120a and the wavelength conversion element 1.

The movable mirror unit 520 is composed of a movable mirror 520a which is a mirror capable of changing at least one of a position and an attitude, and a holder 520b which holds the movable mirror 520a by a support portion (not shown). The movable mirror 520a is fixed so that the mirror surface is parallel to the Dy1 direction inclined in the Dz direction with respect to the Dy direction shown in FIG. 24A. The support portion is a support member such as a torsion bar extending in the Dy1 direction in FIG. 24A, and the movable mirror 520a can be tilted in a direction of rotation about the Dy1 direction as a central axis. The tilt angle of the movable mirror 520a with respect to the holder 520b can be changed by using an electrostatic force or an electromagnetic force with the holder 520b.

The semiconductor light emitting device 110 is fixed to the second base 550, and the second base 550 is fixed to the base 50. The movable mirror unit 520 is fixed to the third base 540, and the third base 540 is fixed to the base 50.

In the light emitting device 101C, the printed circuit board 160 is arranged on the bottom surface side of the base 50. Further, the second printed circuit board 160b to which the semiconductor light emitting device 110 is connected, the wiring of the movable mirror unit 520, and the connector 170 for connecting to the external circuit are connected to the printed circuit board 160.

The emitted light emitted from the semiconductor light emitting device 110 is collected by the lens 120a and becomes the emitted light 83. The emitted light 83 is reflected by the movable mirror 520a and then irradiated to the wavelength conversion element 1 as excitation light 84.

The excitation light 84 irradiated to the wavelength conversion element 1 is partially wavelength-converted to fluorescence by the wavelength conversion member 40 of the wavelength conversion element 1, and is composed of a second emitted light 91 made of fluorescence and scattered light of the excitation light 84. 1 The emitted light 95 is composed of the emitted light 85 and is emitted from the light emitting device 101C.

The light emitting device 101C includes a connector 170. The connector 170 is a connector that can be connected to an external circuit. External power can be applied to the printed circuit board 160 connected to the movable mirror unit 520 and the semiconductor light emitting device 110 via the connector 170. As a result, by adjusting the electric power applied to the semiconductor light emitting device 110 and the movable mirror unit 520, the light emitting pattern of the emitted light 95 emitted from the wavelength conversion element 1 can be set more freely.

The light projecting member 220 constituting the lighting device 201C is a lens in the present embodiment. The light projecting member 220 is held by the fourth base 221 and is attached to the base 50 on the wavelength conversion element 1 side of the light emitting device 101C.

Subsequently, the irradiation region of the excitation light 84 on the wavelength conversion element 1 will be described with reference to FIG. 24B. FIG. 24B is an enlarged cross-sectional view of the wavelength conversion element 1 and its periphery according to the present embodiment. FIG. 24B also shows a top view of the wavelength conversion element 1 according to the present embodiment with respect to the wavelength conversion member 40. The enlarged cross-sectional view of FIG. 24B corresponds to the cross-sectional view taken along the line XXIVB-XXIVB shown in the top view of FIG. 24B.

The top view of FIG. 24B shows the irradiation region 84a of the excitation light 84 at a certain time point. In the present embodiment, the irradiation region 84a can move, that is, scan the irradiation region 84a in the Sx1 direction or the Sx2 direction by changing the tilt direction of the movable mirror 520a. By periodically scanning the irradiation region 84a for a time sufficiently shorter than the afterimage time of the human eye, the wavelength conversion element 1 can emit light as an apparent light emitting region of the scanning region 84w, which is the scanning range. ..

At this time, by adjusting the power and timing applied to the semiconductor light emitting device 110 and the movable mirror unit 520 so that the excitation light 84 is not irradiated in a part of the scanning region 84w, any arbitrary scanning region 84w can be used. In time, it is possible to set a region to be irradiated with the excitation light 84 and a region not to be irradiated with the excitation light 84. That is, the non-irradiated region can be created by turning off the electric power applied to the semiconductor light emitting device 110 in an arbitrary tilting direction of the movable mirror 520a.

FIG. 24C is a schematic perspective view showing the lighting device 201C according to the present embodiment and the projection image 99 projected from the lighting device 201C. As shown in FIG. 24C, the illuminating device 201C can form a non-irradiated region 599 at any place of the projected image 99 formed on the projection object 199. The non-irradiated area 599 can be freely arranged in the projection range. Therefore, when the lighting device 201C of the present embodiment is used as a headlight of a vehicle, it can be applied to an adaptive driving beam.

Subsequently, a method for manufacturing the wavelength conversion element 1 used in the present embodiment will be described with reference to FIG. 24D. FIG. 24D is a photograph showing the shape of the wavelength conversion member 40 according to the present embodiment. More specifically, FIG. 24D shows, for example, a plurality of reflective members 3 formed on the support surface 2a of the wafer-like support member 2 which is a silicon substrate, and further, using screen printing as in the first embodiment. It is a photograph of a part of what formed the wavelength conversion member 40 of. Note that FIG. 24D also shows a schematic top view of the wavelength conversion member 40 in an enlarged manner.

As shown in FIG. 24D, the wavelength conversion member 40 according to the present embodiment has a length in the horizontal direction (that is, a longitudinal direction) of 10 mm in the top view of the support surface 2a and a length in the vertical direction (that is, a width). It has a rectangular shape with a length of 3 mm (direction), and is formed with a pitch of 15 mm in the horizontal direction and a pitch of 4 mm in the vertical direction. Therefore, after forming the wavelength conversion member 40, the wavelength conversion element 1 is manufactured by cutting the wafer-shaped support member 2 at a predetermined pitch.

Subsequently, the cross-sectional shape of the wavelength conversion element 1 manufactured by the above method will be described with reference to FIGS. 24E to 24G. 24E to 24G are graphs showing the measurement results of the film thickness of the wavelength conversion element 1 according to the present embodiment. 24E to 24G show the film thicknesses of the cross sections of the XXIVE-XXIVE line, the XXIVF-XXIVF line, and the XXIVG-XXIVG line shown in FIG. 24D, respectively. In the XXIVF-XXIVF line and the XXIVG-XXIVG line, the film thickness of the central region is about 20 μm as in the first embodiment, and the film thickness of the peripheral region is slightly thicker than that of the central region. That is, the wavelength conversion member 40 has a concave shape. Further, in the XXIVE-XXIVE line, the film thickness of the wavelength conversion member 40 is constant at about 20 μm. Therefore, the wavelength conversion member 40 according to the present embodiment has a long shape in the top view of the support surface 2a, and the first top portion described in the first embodiment is the longitudinal direction of the wavelength conversion member 40. Placed at the end in the direction perpendicular to.

In the wavelength conversion member 40 having such a configuration, the film thickness of the wavelength conversion member 40 can be made constant with respect to the long axis direction of the scanning region 84w shown in FIG. 24B. On the other hand, by forming the concave shape in the short axis direction of the scanning region 84w, the change in chromaticity is small, and the wavelength conversion member 40 is separated from the support member 2 in response to the temperature change of the wavelength conversion element. Can be suppressed. FIG. 24H is a graph showing the simulation results of the color distribution in the light emitting region of the wavelength conversion element 1 based on the film thickness distribution of the wavelength conversion member 40. The horizontal axis indicates the position, and the vertical axis indicates the chromaticity x. As shown in FIG. 24H, it can be seen that a light emitting device having a small color distribution can be realized in a wide light emitting region.

Even in the light emitting device 101C and the lighting device 201C having the above-mentioned configuration, the same effect as that of the light emitting device 101 and the lighting device 201 according to the first embodiment can be obtained. Further, in the present embodiment, since the excitation light is scanned on the wavelength conversion element 1 by using the movable mirror unit, the degree of freedom of the pattern of the projected image 99 can be increased.

(Embodiment 6)
Subsequently, the light emitting device according to the sixth embodiment will be described with reference to FIGS. 25A to 25C. In the above embodiment, as the configuration of the light emitting device, the excitation light is irradiated from diagonally above one of the wavelength conversion elements. However, in the light emitting device according to the present embodiment, by irradiating the excitation light from a plurality of directions, it is possible to radiate light having a larger amount of light from the wavelength conversion element. FIG. 25A is a schematic cross-sectional view showing the irradiation direction of the wavelength conversion element 1F and the excitation light 84 in the light emitting device according to the present embodiment. As shown in FIG. 25A, in the present embodiment, the excitation light 84 is irradiated from two directions, one diagonally above the wavelength conversion element 1F and the other diagonally above the wavelength conversion element 1F according to the fourth embodiment. In the configuration example shown in FIG. 25A, the wavelength conversion element 1F is irradiated with excitation light from two directions along two optical paths symmetric to the plane orthogonal to the support surface 2a through the excitation region of the excitation light 84. ..

The results of experiments carried out using this configuration example will be described with reference to FIGS. 25B and 25C. FIG. 25B is a graph showing the luminance distribution in the light emitting region of the wavelength conversion element 1F according to the present embodiment. FIG. 25C is a table showing an outline of the experimental results of the light emitting device according to the present embodiment. 25B and 25C show the experimental results when the wavelength conversion element 1F is irradiated with the excitation light 84 having an optical output of 3.5 W from each of the two directions. That is, in this experiment, the wavelength conversion element 1F was irradiated with the excitation light 84 having a total light output of 7 W. At this time, the diameter of the light emitting region was adjusted to be approximately 1 mm. In this case as well, as in the first embodiment, as shown in the luminance distribution in the light emitting region of FIG. 25B, the peak luminance exceeding 1000 cd / mm ² and the wavelength conversion member in the light emitting region of 125 ° C. or less of 150 ° C. A surface temperature of 40 could be achieved. At this time, as shown in FIG. 25C, assuming that the region having a luminance of 1 / e ² or more of the peak luminance is the emission region size, the direction parallel to the paper surface of FIG. 25A (the direction parallel to the plane containing the excitation light). The width of the light emitting region was 0.9 mm, and the width of the light emitting region in the direction perpendicular to the paper surface of FIG. 25A (the direction perpendicular to the plane containing the excitation light) was 1.1 mm. A luminous flux of 1000 lm or more could be emitted from this light emitting region. This luminous flux is very high as a luminous flux from a minute light emitting region as described above.

As described above, according to the light emitting device that irradiates the wavelength conversion element 1F with a plurality of excitation lights, it is possible to radiate a large amount of synchrotron radiation while maintaining the surface temperature of the wavelength conversion element 1F below a predetermined temperature. can. Further, in the present embodiment, regarding the top portion around the wavelength conversion element 1F, the top portion formed in the plane parallel to the paper surface of FIG. 25A is formed as the second top portion, passing through the excitation region and forming in the direction perpendicular to the paper surface. The top may be the first top, and the height of the second top from the support surface 2a may be lower than the height of the first top from the support surface 2a. In other words, the height from the support surface 2a of the second apex arranged in the plane containing the excitation light 84 is set to the support surface 2a of the first apex arranged in the plane perpendicular to the plane passing through the excitation region. It may be lower than the height from. With this configuration, it is possible to prevent a part of the excitation light 84 from being kicked at the second top.

In the above configuration, two cases have been described as a plurality of excitation lights, but the present invention is not limited to this. Similar applications can be applied even when three or more excitation lights are used.

(Other variants, etc.)
Although the present disclosure has been described above based on each embodiment, the present disclosure is not limited to these embodiments. As long as the gist of the present disclosure is not deviated, various modifications that can be conceived by those skilled in the art are applied to the present embodiment, and other forms constructed by combining some components in the embodiment are also within the scope of the present disclosure. Included in.

For example, in the second embodiment and the like, an example in which a transparent material is used as the scattered particles 43 is shown, but a material other than the transparent material may be used as the scattered particles 43. The material forming the scattered particles 43 may be any material that absorbs little absorption of excitation light and fluorescence and scatters the excitation light, and may be, for example, a white resin.

Further, the wavelength conversion member 40F according to the fourth embodiment has the shape characteristics of the wavelength conversion member 40 according to the first embodiment, but the configuration of the wavelength conversion member 40F according to the fourth embodiment is not limited to this. .. That is, the wavelength conversion member 40F according to the fourth embodiment does not have to have the same shape as the wavelength conversion member 40 according to the first embodiment. For example, the film thickness of the wavelength conversion member 40F may be substantially constant over the entire region.

As described above, the wavelength conversion element of the present disclosure can suppress the temperature rise of the wavelength conversion member with respect to the excitation light having a high light density, and can easily adjust the chromaticity coordinates of the emitted light. A light emitting device using an element can easily emit high-intensity emitted light. Therefore, the wavelength conversion element of the present disclosure and a light emitting device using the same are useful in various lighting devices such as headlights of vehicles, ships, and trains, light sources for projectors, light sources for spotlights, and light sources for medical use.

1, 1B, 1C, 1D, 1F Wavelength conversion element 2 Support member 2a Support surface 2d Arrangement area 3 Reflective member 3a Adhesive layer 3b First reflective film 3c Second reflective film 5a Micro-convex part 5b Micro-concave 6 Radiation surface 6a Peripheral area 6b Central region 7 Joint surface 40, 40B, 40C, 40D, 40F Frequency conversion member 41 First phosphor particle 42 Transparent binder 43 Scattered particle 44 Second phosphor particle 45 Void 50 Base 50a Storage part 50b Side wall 51 Light-shielding cover 52 Screw 53, 520b Holder 55 Adhesive member 81, 83, 95 Emission light 84 Excitation light 85 First emission light 91 Second emission light 96 Projection light 99 Projection image 101, 101B, 101C Light emitting device 110 Semiconductor light emitting device 111 Semiconductor light emitting element 120 Condensing optical member 120a Lens 120b Reflecting optical element 120c Condensing lens 130 Optical detector 140 Translucent member 150 Excitation area 151 Light emitting area 160 Print circuit board 160b 2nd print circuit board 170 Connector 190 Rotation mechanism 191 Rotation axis 199 Projection target Object 201, 201B, 201C Lighting device 220 Floodlight member 221 4th base 314B, 314R Dichroic mirror 320 Light source unit 325 Heat sink 331B, 332B, 331R, 332R Reflection mirror 350B, 350G, 350R Image display element 360 Dichroic prism 365 Projection lens 379B Blue light 379Y Yellow light 379G Green light 379R Red light 380B, 380G, 380R Signal light 389 Projection light 520 Movable mirror unit 520a Movable mirror 540 3rd base 550 2nd base 599 Non-irradiation area 1063 Light emitting device (light source device)
1070 Excited light source 1071 Fluorescent wheel 1075 Light guide 1130 Base material 1131 Fluorescent layer 1138 Reflective layer 1139 Excited light condensing lens P1 1st top S1 1st tilted part

Claims (23)

A support member having a support surface and
A wavelength conversion member arranged above the support surface is provided.
The wavelength conversion member has a radiation surface located on the opposite side of the support surface and has a radiation surface.
The radial surface includes a peripheral region including the peripheral edge of the radial surface and a central region surrounded by the peripheral region.
At least a part of the peripheral region is arranged at a position opposite to the central region and a first apex projecting from the central region in a direction away from the support surface, and the support is provided. It has a second apex that protrudes from the central region in a direction away from the surface .
The radial surface is inclined toward the support surface side from the first top portion toward the central region and toward the support surface side from the second top portion toward the central region. Has a second sloping portion and
The height of the first top is higher than that of the second top from the support surface.
Wavelength conversion element. The wavelength conversion element according to claim 1, wherein the central region includes a flat portion having a gentler inclination than the first inclined portion. The wavelength conversion element according to claim 1 or 2, wherein a plurality of minute convex portions are formed on the radial surface of the first inclined portion. The wavelength conversion element according to any one of claims 1 to 3, wherein the arrangement region on the support surface on which the wavelength conversion member is arranged is a plane. The wavelength conversion element according to any one of claims 1 to 4, wherein the film thickness at the first top of the wavelength conversion member is thicker than the film thickness in the central region. The wavelength conversion element according to any one of claims 1 to 5, wherein the film thickness of the wavelength conversion member in the central region is 15 μm or more and 35 μm or less. The wavelength conversion element according to any one of claims 1 to 6, wherein the wavelength conversion member includes a plurality of first phosphor particles made of the same material in the central region and the first top portion. The wavelength conversion element according to claim 7, wherein the wavelength conversion member includes a transparent coupling material that binds the plurality of first phosphor particles. The wavelength conversion element according to claim 8, wherein the wavelength conversion member includes a plurality of scattered particles bonded to the transparent coupling material. The wavelength conversion element according to claim 9 , wherein the scattered particles include a metal oxide or a nitride. The wavelength conversion element according to any one of claims 7 to 10 , wherein the total volume of the plurality of first phosphor particles is 35% or more and 62% or less with respect to the volume of the wavelength conversion member. In the cross section of the wavelength conversion member, the total cross-sectional area of the plurality of first phosphor particles is 40% or more and 80% or less with respect to the cross - sectional area of the wavelength conversion member. The wavelength conversion element according to the section. A plurality of minute convex portions are formed on the radial surface of the first inclined portion.
According to any one of claims 7 to 12, at least a part of the plurality of minute protrusions is formed by projecting a part of the plurality of first phosphor particles on the radiation surface. The wavelength conversion element described. The wavelength conversion member includes a plurality of second phosphor particles different from the plurality of first phosphor particles.
The plurality of first phosphor particles were Ce-activated (Y _x Gd _1-x ) ₃ (Aly Ga _{1-y ) 5} O ₁₂ (0.5 ≦ x ≦ 1, 0.5 ≦ y ≦). 1) or Ce-activated (La _1-x1 , Y _x1 ) ₃ Si ₆ N ₁₁ (0 ≦ x1 ≦ 1).
The plurality of second phosphor particles include any of claims 7 to 13 including Ce-activated (La _1-x2 , Y _x2 ) ₃ Si ₆ N ₁₁ (0 ≦ x2 ≦ 1, x1 ≠ x2). The wavelength conversion element according to item 1. The wavelength conversion element according to claim 14 , wherein the plurality of first phosphor particles and the plurality of second phosphor particles have a median diameter of 2 μm or more and 30 μm or less. The wavelength conversion element according to claim 14 or 15 , wherein the plurality of first phosphor particles and the plurality of second phosphor particles have a median diameter of 3 μm or more and 9 μm or less. In the top view of the support surface, the wavelength conversion member has an elongated shape and has a long shape.
The wavelength conversion element according to any one of claims 1 to 16 , wherein the first top portion is arranged at an end portion in a direction perpendicular to the longitudinal direction of the wavelength conversion member. The wavelength conversion element according to any one of claims 1 to 17 , further comprising a reflection member arranged between the wavelength conversion member and the support member. The wavelength conversion element according to any one of claims 1 to 18 , wherein the support member includes silicon (Si), silicon carbide (SiC), sapphire (Al ₂ O ₃ ), aluminum nitride (AlN), or diamond. .. The wavelength conversion element according to any one of claims 1 to 19 .
A light emitting device including an excitation light source that irradiates the wavelength conversion element with excitation light.
A light emitting device having a luminance of 1000 cd / mm ² or more of light emitted from the light emitting device. The wavelength conversion element according to any one of claims 1 to 19 .
A light emitting device including an excitation light source that irradiates the wavelength conversion element with excitation light.
The excitation light is obliquely incident on the radiation surface from the second top side.
The wavelength conversion member is a light emitting device that converts the excitation light into wavelength. The light emitting device according to claim 20 or 21 and
A lighting device including a light projecting member to which light emitted from the light emitting device is incident and emits projected light. The projection of a straight line orthogonal to the optical axis of the excitation light at a position where the excitation light is incident on the wavelength conversion member, including a straight line parallel to the support surface, and a plane perpendicular to the support surface. The lighting device according to claim 22, wherein the light is emitted from the plane to the excitation light source side.

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