Wavelength conversion device, light source device, and projector

Abstract

To provide a wavelength conversion device, a light source device, and a projector which can stably hold a phosphor and can efficiently cool the phosphor to generate a bright fluorescence.SOLUTION: The wavelength conversion device includes: a phosphor on which excitation light is radiated; a substrate having a first surface; and a joint layer for joining the phosphor to the first surface of the substrate. The joint layer includes an adhesive and a plurality of first fillers mixed in the adhesive and having a longer axis. The direction of the first fillers along the longer axis is located in a direction perpendicular to the first surface of the substrate, and the thermal conductivity of the first fillers is higher than the thermal conductivity of the adhesive.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a wavelength conversion device, a light source device, and a projector. [Background technology]

[0002] Conventionally, light source devices proposed for use in projectors use fluorescence emitted from a phosphor when the phosphor is irradiated with excitation light. In order to generate bright fluorescence, it is necessary to improve the cooling performance of the phosphor.

[0003] Patent Document 1 listed below discloses a technique in which a filler with high thermal conductivity is contained in an adhesive that bonds a substrate and a phosphor, thereby efficiently transferring heat from the phosphor to the substrate. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2020-42236 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, since the filler used in the light source device is spherical, the heat path is well formed in the area where the fillers are close to each other, but the heat path is blocked in other areas, making it difficult to efficiently transfer the heat of the phosphor to the substrate. Therefore, it is possible to increase the filling rate of the filler to make it easier to form a heat path, but increasing the filling rate of the filler reduces the amount of adhesive, which may cause the phosphor to peel off or break due to a decrease in the adhesive strength of the adhesive. [Means for solving the problem]

[0006] In order to solve the above problems, according to one aspect of the present invention, there is provided a wavelength conversion device comprising: a phosphor to be irradiated with excitation light; a substrate having a first surface; and a bonding layer for bonding the phosphor to the first surface of the substrate, the bonding layer including an adhesive and a plurality of first fillers having a longitudinal axis and mixed into the adhesive, the plurality of first fillers being positioned such that a direction along the longitudinal axis intersects with the first surface of the substrate, and the thermal conductivity of the first fillers is higher than that of the adhesive.

[0007] According to another aspect of the present invention, there is provided a light source device including the wavelength conversion device of the above aspect and an excitation light source that irradiates the excitation light toward the wavelength conversion device.

[0008] According to another aspect of the present invention, there is provided a projector comprising a light source device of the above aspect, a light modulation device that modulates light emitted from the light source device, and a projection optical device that projects the light modulated by the light modulation device. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a schematic configuration diagram of a projector according to a first embodiment. [Diagram 2] 1 is a schematic configuration diagram showing a light source device according to a first embodiment. [Diagram 3] FIG. 2 is a cross-sectional view showing a configuration of a main part of a bonding layer according to the first embodiment. [Figure 4] FIG. 6 is an enlarged view showing a configuration of a main part of a wavelength converter according to a second embodiment. [Diagram 5] FIG. 11 is an enlarged view showing a configuration of a main part of a wavelength converter according to a third embodiment. [Figure 6] FIG. 13 is an enlarged view showing a configuration of a main part of a wavelength converter according to a fourth embodiment. [Figure 7] FIG. 13 is an enlarged view showing a configuration of a main part of a wavelength converter according to a fifth embodiment. [Figure 8] FIG. 13 is an enlarged view showing a configuration of a main part of a wavelength converter according to a sixth embodiment. [Figure 9]FIG. 13 is an enlarged view showing a configuration of a main part of a wavelength converter according to a seventh embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. Note that the drawings used in the following description may show characteristic parts in an enlarged scale for the sake of convenience in order to make the characteristics easier to understand, and the dimensional ratios of each component may not necessarily be the same as in reality.

[0011] (First embodiment) FIG. 1 is a schematic configuration diagram of a projector according to the present embodiment. 1, the projector 1 of this embodiment is a projection type image display device that displays an image on a screen SCR. The projector 1 includes a light source device 2, a color separation optical system 3, a light modulation device 4R, a light modulation device 4G, a light modulation device 4B, a synthesis optical system 5, and a projection optical device 6.

[0012] The light source device 2 emits white illumination light WL toward the color separation optical system 3. The configuration of the light source device 2 will be described in detail later.

[0013] The color separation optical system 3 separates the illumination light WL emitted from the light source device 2 into red light LR, green light LG, and blue light LB. The color separation optical system 3 includes a first dichroic mirror 7a, a second dichroic mirror 7b, a first total reflection mirror 8a, a second total reflection mirror 8b, a third total reflection mirror 8c, a first relay lens 9a, and a second relay lens 9b.

[0014] The first dichroic mirror 7a separates the illumination light WL from the light source device 2 into red light LR and light containing green light LG and blue light LB. The first dichroic mirror 7a transmits the red light LR and reflects the light containing green light LG and blue light LB. On the other hand, the second dichroic mirror 7b reflects the green light LG and transmits the blue light LB. In this way, the second dichroic mirror 7b separates the light containing green light LG and blue light LB into green light LG and blue light LB.

[0015] The first total reflection mirror 8a is disposed in the optical path of the red light LR and reflects the red light LR transmitted through the first dichroic mirror 7a toward the optical modulation device 4R. On the other hand, the second total reflection mirror 8b and the third total reflection mirror 8c are disposed in the optical path of the blue light LB and guide the blue light LB transmitted through the second dichroic mirror 7b to the optical modulation device 4B. The green light LG is reflected from the second dichroic mirror 7b toward the optical modulation device 4G.

[0016] The first relay lens 9a and the second relay lens 9b are disposed on the light exit side of the second total reflection mirror 8b in the optical path of the blue light LB. The first relay lens 9a and the second relay lens 9b compensate for the optical loss of the blue light LB caused by the optical path length of the blue light LB being longer than the optical path lengths of the red light LR and the green light LG.

[0017] The light modulation device 4R modulates the red light LR according to image information to form image light corresponding to the red light LR. The light modulation device 4G modulates the green light LG according to image information to form image light corresponding to the green light LG. The light modulation device 4B modulates the blue light LB according to image information to form image light corresponding to the blue light LB.

[0018] For example, a transmissive liquid crystal panel is used for each of the light modulation device 4R, the light modulation device 4G, and the light modulation device 4B. Furthermore, a polarizing plate (not shown) is disposed on each of the incident side and the exit side of the liquid crystal panel.

[0019] A field lens 10R is disposed on the incident side of the optical modulation device 4R. The field lens 10R collimates the red light LR incident on the optical modulation device 4R. A field lens 10G is disposed on the incident side of the optical modulation device 4G. The field lens 10G collimates the green light LG incident on the optical modulation device 4G. A field lens 10B is disposed on the incident side of the optical modulation device 4B. The field lens 10B collimates the blue light LB incident on the optical modulation device 4B.

[0020] The image light emitted from the light modulation device 4R, the light modulation device 4G, and the light modulation device 4B is incident on the combining optical system 5. The combining optical system 5 combines the image light corresponding to the red light LR, the green light LG, and the blue light LB, respectively, and emits the combined image light toward the projection optical device 6. The combining optical system 5 uses, for example, a cross dichroic prism.

[0021] The projection optical device 6 has a plurality of projection lenses. The projection optical device 6 enlarges and projects the image light combined by the combining optical system 5 onto the screen SCR. As a result, an enlarged image is displayed on the screen SCR.

[0022] The configuration of the light source device 2 will be described below. FIG. 2 is a schematic diagram showing the configuration of a light source device 2 of the present embodiment. As shown in FIG. 2, the light source device 2 includes a first light source 40, a collimating optical system 41, a dichroic mirror 42, a collimating focusing optical system 43, a wavelength conversion device 20, a second light source 44, a focusing optical system 45, a diffuser 46, and a collimating optical system 47.

[0023] The first light source 40 is an excitation light source that irradiates excitation light E toward the wavelength conversion device 20. The first light source 40 is composed of a semiconductor laser 40a that emits blue excitation light E made of laser light. The emission intensity of the excitation light E has a peak of, for example, 445 nm. Note that, as the semiconductor laser 40a, a semiconductor laser that emits blue light of a wavelength other than 445 nm, for example, 455 nm or 460 nm, can also be used. The optical axis ax of the first light source 40 is perpendicular to the illumination optical axis 100ax of the light source device 2. Note that the first light source 40 may be configured by arranging a plurality of semiconductor lasers 40a in an array in one plane perpendicular to the optical axis ax of the first light source 40.

[0024] The collimating optical system 41 includes a first lens 41a and a second lens 41b. The collimating optical system 41 approximately collimates the light emitted from the first light source 40. Each of the first lens 41a and the second lens 41b is formed of a convex lens.

[0025] The dichroic mirror 42 is disposed in the optical path from the collimating optical system 41 to the collimating focusing optical system 43 in a direction intersecting at an angle of 45° with respect to both the optical axis ax of the first light source 40 and the illumination optical axis 100ax. The dichroic mirror 42 reflects the blue light component and transmits the red light component and the green light component. Thus, the dichroic mirror 42 reflects the excitation light E and blue light B described below, and transmits the yellow fluorescence Y.

[0026] The collimating condensing optical system 43 condenses the excitation light E transmitted through the dichroic mirror 42 and makes it incident on the wavelength conversion device 20, and also approximately collimates the fluorescence Y emitted from the wavelength conversion device 20. The collimating condensing optical system 43 includes a first lens 43a and a second lens 43b. Each of the first lens 43a and the second lens 43b is formed by a convex lens.

[0027] The second light source 44 is composed of a semiconductor laser having the same wavelength band as the first light source 40. The second light source 44 may be composed of one semiconductor laser, or may be composed of multiple semiconductor lasers. The second light source 44 may also be composed of a semiconductor laser having a different wavelength band from the semiconductor laser of the first light source 40.

[0028] The light collecting optical system 45 includes a first lens 45a and a second lens 45b. The light collecting optical system 45 collects the blue light B emitted from the second light source 44 on or near the diffusion surface of the diffusion plate 46. Each of the first lens 45a and the second lens 45b is formed of a convex lens.

[0029] The diffusion plate 46 diffuses the blue light B emitted from the second light source 44, and generates blue light B having a light distribution close to the light distribution of the fluorescence Y emitted from the wavelength conversion device 20. As the diffusion plate 46, for example, ground glass made of optical glass can be used.

[0030] The collimating optical system 47 includes a first lens 47a and a second lens 47b. The collimating optical system 47 approximately collimates the light emitted from the diffusion plate 46. Each of the first lens 47a and the second lens 47b is formed of a convex lens.

[0031] The blue light B emitted from the second light source 44 is reflected by the dichroic mirror 42, emitted from the wavelength conversion device 20, and combined with the fluorescence Y transmitted through the dichroic mirror 42 to generate white illumination light WL. The illumination light WL is incident on the uniform illumination optical system 80.

[0032] The uniform illumination optical system 80 includes a first lens array 81, a second lens array 82, a polarization conversion element 83, and a superimposing lens 84.

[0033] The first lens array 81 has a plurality of first lenses 81a for dividing the illumination light WL from the light source device 2 into a plurality of partial light beams. The plurality of first lenses 81a are arranged in a matrix in a plane perpendicular to the illumination optical axis 100ax.

[0034] The second lens array 82 has a plurality of second lenses 82a corresponding to the plurality of first lenses 81a of the first lens array 81. The plurality of second lenses 82a are arranged in a matrix in a plane perpendicular to the illumination optical axis 100ax.

[0035] The second lens array 82, together with the superimposing lens 84, forms images of the first lenses 81a of the first lens array 81 near the image forming areas of the light modulation device 4R, the light modulation device 4G, and the light modulation device 4B, respectively.

[0036] The polarization conversion element 83 converts the light emitted from the second lens array 82 into one type of linearly polarized light. The polarization conversion element 83 includes, for example, a polarization separation film and a phase difference plate (not shown).

[0037] The superimposing lens 84 collects the partial light beams emitted from the polarization conversion element 83 and superimposes them near the image forming areas of the light modulation device 4R, the light modulation device 4G, and the light modulation device 4B.

[0038] Next, the configuration of the wavelength converter 20 will be described. The wavelength converter 20 includes a rotation driver 21 , a wheel substrate 22 , a phosphor 23 , a heat dissipation member 24 , and a bonding layer 25 .

[0039] The rotation drive unit 21 is configured by a motor device. The rotation drive unit 21 has a rotation shaft unit 21a that is rotatable around a rotation axis O that is an imaginary axis line. The rotation shaft unit 21a supports the wheel substrate 22 so that the wheel substrate 22 is rotatable.

[0040] The wheel substrate 22 has a front surface 22a as a first surface and a back surface 22b as a second surface opposite to the first surface. The wheel substrate 22 is made of a disk-shaped or annular metal plate having excellent heat dissipation properties, such as aluminum or copper.

[0041] The phosphor 23 is provided on the surface 22 a of the wheel substrate 22 . The phosphor 23 is formed in an annular shape around the rotation axis O on the surface 22a of the wheel substrate 22. That is, the phosphor 23 is provided around the rotation axis O in a ring shape.

[0042] The phosphor 23 generates heat when emitting the fluorescence Y. If the temperature of the phosphor 23 becomes too high, the wavelength conversion efficiency of the fluorescence Y may decrease, and the amount of emitted fluorescence Y may decrease. In the wavelength converter 20 of this embodiment, the phosphor 23 rotates together with the wheel substrate 22, so that the incident position of the excitation light E on the phosphor 23 can be moved over time. This improves the cooling performance of the phosphor 23, thereby suppressing the decrease in the fluorescence conversion efficiency associated with an increase in the temperature of the phosphor 23.

[0043] Phosphor 23 converts the wavelength of excitation light E irradiated from upper surface 23a into fluorescence Y and emits it from upper surface 23a. Phosphor 23 is a wavelength conversion member including a ceramic phosphor made of a polycrystalline phosphor. The wavelength band of fluorescence Y is, for example, a yellow wavelength band of 490 to 750 nm. In other words, fluorescence Y is yellow fluorescence including a red light component and a green light component.

[0044] Phosphor 23 may contain a single crystal phosphor instead of a polycrystalline phosphor, or may be made of a material in which a large number of phosphor particles are dispersed in a binder made of glass or resin.

[0045] Specifically, the material of the phosphor 23 in this embodiment includes, for example, an yttrium-aluminum-garnet (YAG) phosphor. Taking YAG:Ce containing cerium (Ce) as an activator as an example, the material of the phosphor 23 may be a material obtained by mixing raw material powders containing constituent elements such as Y2O3, Al2O3, and CeO3 and reacting them in a solid state, Y-Al-O amorphous particles obtained by a wet method such as a coprecipitation method or a sol-gel method, or YAG particles obtained by a gas phase method such as a spray drying method, a flame pyrolysis method, or a thermal plasma method.

[0046] The bonding layer 25 bonds the phosphor 23 to the front surface 22a of the wheel substrate 22. The wheel substrate 22 has a reflective surface 26a that is in contact with the bonding layer 25 and reflects light. The reflective surface 26a reflects the light that is emitted from the back surface 23b of the phosphor 23 and transmitted through the bonding layer 25 toward the upper surface 23a. This can further increase the efficiency of extracting light from the upper surface 23a of the phosphor 23. In this embodiment, the reflective surface 26a is formed by the surface of a reflective layer 26 provided between the bonding layer 25 and the surface 22a of the wheel substrate 22. The reflective layer 26 is formed by a vapor deposition film of a highly reflective material, such as Al or Ag. In this embodiment, the reflective layer 26 is formed by an Ag film with high reflectivity. Note that when the surface 22a of the wheel substrate 22 has light reflectivity, a part of the surface 22a may be used as the reflective surface.

[0047] The heat dissipation member 24 constitutes a heat sink having a base portion 24a and a plurality of heat dissipation fins 24b. The base portion 24a is made of a disk made of a metal having excellent heat dissipation properties, such as aluminum or copper. The base portion 24a has the same outer shape as the wheel substrate 22 and is joined to the rear surface 22b of the wheel substrate 22. The plurality of heat dissipation fins 24b are located radially outside the rotation drive unit 21 and extend radially toward the outer edge side of the base portion 24a.

[0048] The heat of the wheel substrate 22 is transferred to the base portion 24a of the heat dissipation member 24. The heat dissipation member 24 rotates together with the wheel substrate 22 about the rotation axis O to generate an airflow between the multiple heat dissipation fins 24b, thereby dissipating the heat of the base portion 24a. In this manner, the heat dissipation member 24 dissipates the heat of the wheel substrate 22.

[0049] In the wavelength converter 20 , the heat of the phosphor 23 is transferred to the bonding layer 25 and then to the wheel substrate 22 via the bonding layer 25 . The present inventors have noticed that by favorably forming a thermal path from the phosphor 23 to the wheel substrate 22 in the bonding layer 25, the heat of the phosphor 23 can be efficiently transferred to the wheel substrate 22. Then, they have found the configuration of the bonding layer 25 of the wavelength converter 20 of the present embodiment.

[0050] FIG. 3 is an enlarged cross-sectional view showing a main configuration of the bonding layer 25. As shown in FIG. 3, the bonding layer 25 of the present embodiment includes an adhesive 27 and a plurality of first fillers 28 mixed in the adhesive 27. The thickness of the bonding layer 25 is desirably set to 10 μm to 20 μm.

[0051] Each of the first fillers 28 has a rod-like shape. Here, the rod-like shape refers to a shape that extends in one direction, and may be an oblong spheroid shape with an elliptical cross section, or a needle-like shape with pointed ends. Therefore, the first filler 28 having a rod-like shape has a longitudinal axis Lx along the longitudinal direction.

[0052] The multiple first fillers 28 are positioned in a direction along the longitudinal axis Lx that intersects with the surface 22a of the wheel substrate 22. That is, the multiple first fillers 28 are mixed in the adhesive 27 in a state inclined rather than parallel to the surface 22a of the wheel substrate 22. Therefore, each first filler 28 is disposed in the adhesive 27 in a direction in which the longitudinal axis Lx is aligned with the thickness direction of the bonding layer 25.

[0053] 3, each of the multiple first fillers 28 has a rod-like shape, but the multiple first fillers 28 are folded over and over again within the adhesive 27, forming a fibrous shape as a whole. In other words, the bonding layer 25 of the present embodiment is composed of the adhesive 27 and the multiple first fillers 28 that are fibrous.

[0054] In this embodiment, the multiple first fillers 28 include fillers 28a in contact with the phosphor 23 and fillers 28b in contact with the wheel substrate 22. Specifically, the fillers 28a are in contact with the rear surface 23b of the phosphor 23, and the fillers 28b are indirectly in contact with the front surface 22a of the wheel substrate 22 via the reflective layer 26.

[0055] In this embodiment, the plurality of first fillers 28 include elongated fillers 28c. Both ends of such elongated fillers 28c are in contact with the rear surface 23b of the phosphor 23 and the reflective surface 26a, respectively.

[0056] The rod-like or fibrous first filler 28 is preferably made of a material with excellent thermal conductivity, such as titanium oxide, alumina (Al2O3), carbon, carbon nanotubes, boron nitride (BN), BN nanotubes, etc. Table 1 below shows the physical property data for each filler material. Table 1 also shows the physical properties of the filler materials, which will be described later.

[0057] [Table 1]

[0058] As shown in Table 1, the filler made of titanium oxide has an average particle size of several to several tens of μm, an optical reflectance of 90 to 98%, and a thermal conductivity of 7.5 to 10.5 W / m·K. The filler made of alumina (Al2O3) has an average particle size of several to several tens of μm, an optical reflectance of 90%, and a thermal conductivity of 20 W / m·K. The filler made of boron nitride (BN) has an average particle size of 1 μm or less, an optical reflectance of 95%, and a thermal conductivity of 200 W / m·K. The filler made of BN nanotubes has an average particle size of several μm, an optical reflectance of 95%, and a thermal conductivity of approximately 3000 W / m·K. The filler made of carbon has an average particle size of 50 μm, an optical reflectance of 5% or less, and a thermal conductivity of 2000 W / m·K or less. Moreover, the filler made of carbon nanotubes has an average particle size of 1 μm or less, an optical reflectance of 5% or less, and a thermal conductivity of 3000 to 6000 W / m·K or less.

[0059] In this embodiment, the adhesive 27 is made of a resin material having optical transparency, such as silicone resin. The adhesive 27 made of silicone resin has a thermal conductivity of about 0.15 W / m·K. In the bonding layer 25 of the present embodiment, the thermal conductivity of the first filler 28 is higher than the thermal conductivity of the adhesive 27 .

[0060] Next, the operation of the wavelength converter 20 of this embodiment will be described. For ease of understanding, a heat path HC that is a path of heat transferred from the phosphor 23 side to the wheel substrate 22 side is indicated by a dashed line in Fig. 3.

[0061] In the wavelength converter 20 of the present embodiment, heat of the phosphor 23 is conducted from the rear surface 23b of the phosphor 23 to the bonding layer 25. First, the heat of the phosphor 23 is conducted to the filler that is closest to the rear surface 23b among the plurality of first fillers 28. In the case of the present embodiment, the heat of the phosphor 23 is conducted to the filler 28a in contact with the rear surface 23b.

[0062] In the bonding layer 25 of this embodiment, the longitudinal axis Lx of each first filler 28 is aligned along the thickness direction of the bonding layer 25, so that the first fillers 28 are arranged in contact with each other in the thickness direction of the bonding layer 25. Therefore, the heat of the filler 28a is transferred to the first filler 28 in contact with the filler 28a, and then transferred to the first filler 28 closest to the wheel substrate 22. In this embodiment, the heat of the phosphor 23 is transferred to the filler 28b in contact with the reflecting surface 26a of the wheel substrate 22, and then transferred to the wheel substrate 22 via the reflecting layer 26. In other words, the bonding layer 25 forms a heat path HC that transfers the heat of the phosphor 23 to the wheel substrate 22 by the first fillers 28 aligned in the thickness direction, so that the heat of the phosphor 23 can be efficiently released from the wheel substrate 22.

[0063] In the embodiment, both ends of the long filler 28c are in contact with the rear surface 23b and the reflective surface 26a of the phosphor 23, respectively. Therefore, the long filler 28c can form the heat path HC in the bonding layer 25 by itself. It is preferable for the heat path HC from the phosphor 23 side to the wheel substrate 22 side to be in a state where the multiple first fillers 28 are in contact with each other from the back surface 23b to the reflective surface 26a of the phosphor 23, but even if there is some non-contact, the thermal conductivity is higher than that of conventional spherical fillers, so that the partial non-contact state is also effective.

[0064] In the bonding layer 25 of this embodiment, the multiple first fillers 28 are folded multiple times within the adhesive 27 as described above to form a fibrous shape as a whole, and therefore, as shown in Figure 3, multiple similar heat paths HC are formed inside the bonding layer 25. As a result, the heat of the phosphor 23 is transferred to the wheel substrate 22 via the bonding layer 25, and the heat transferred to the wheel substrate 22 is dissipated via the heat dissipation member 24. In addition, the fibrous form is not limited to the multiple first fillers being rod-shaped, but multiple thread-like first fillers may be entangled with each other, and multiple curved first fillers entangled in thread-like form can form a heat path to obtain a similar effect.

[0065] In this embodiment, it is preferable that the reflectance of first filler 28 is higher than the reflectance of adhesive 27. Specifically, by using titanium oxide, alumina (Al2O3), boron nitride (BN), or BN nanotube from Table 1 above as the material of first filler 28, it is possible to make the reflectance of first filler 28 higher than the reflectance of adhesive 27. According to this configuration, the first filler 28 not only constitutes a heat path, which will be described later, but also reflects the fluorescent light Y together with the reflecting surface 26a, thereby making it possible to increase the efficiency with which the fluorescent light Y is extracted.

[0066] (Effects of the first embodiment) The wavelength converter 20 of this embodiment includes a phosphor 23 irradiated with excitation light E, a wheel substrate 22 having a surface 22a, and a bonding layer 25 that bonds the phosphor 23 to the surface 22a of the wheel substrate 22. The bonding layer 25 includes an adhesive 27 and a plurality of first fillers 28 having a longitudinal axis Lx and mixed in the adhesive 27. The plurality of first fillers 28 are located in a direction along the longitudinal axis Lx that intersects with the surface 22a of the wheel substrate 22. The thermal conductivity of the first fillers 28 is higher than the thermal conductivity of the adhesive 27.

[0067] In the wavelength conversion device 20 of this embodiment, the bonding layer 25 is composed of an adhesive 27 and a plurality of rod-shaped or fibrous first fillers 28 mixed into the adhesive 27, the thermal conductivity of the first fillers 28 being higher than the thermal conductivity of the adhesive 27, and the plurality of first fillers 28 form a thermal path HC that transfers heat from the phosphor 23 to the wheel substrate 22.

[0068] According to the wavelength converter 20 of the present embodiment, the heat path HC from the phosphor 23 to the wheel substrate 22 can be formed in the bonding layer 25 by the multiple first fillers 28. Here, if a thermal path is formed in the bonding layer by increasing the filling rate of spherical filler as in conventional technology, the amount of adhesive will decrease, reducing the adhesive strength of the bonding layer, which may result in peeling or damage to the phosphor. In contrast, the bonding layer 25 of the present embodiment efficiently forms a thermal path HC by aligning the longitudinal axis Lx of the rod-shaped first filler 28 along the thickness direction, so that sufficient bonding strength can be obtained without reducing the amount of adhesive. Therefore, according to the wavelength converter 20 of the present embodiment, the phosphor 23 can be stably held and efficiently cooled, thereby increasing the wavelength conversion efficiency of the phosphor 23 and generating bright fluorescence Y.

[0069] The light source device 2 of the present embodiment includes a wavelength conversion device 20 and a first light source 40 serving as an excitation light source that irradiates excitation light E toward the wavelength conversion device 20.

[0070] According to the light source device 2 of the present embodiment, a light source device that has excellent wavelength conversion efficiency and emits illumination light WL containing bright fluorescence Y can be provided.

[0071] The projector 1 of this embodiment includes a light source device 2, light modulation devices 4R, 4G, and 4B that modulate illumination light WL including fluorescence Y emitted from the light source device 2, and a projection optical device 6 that projects the light modulated by the light modulation devices 4R, 4G, and 4B.

[0072] According to the projector 1 of the present embodiment, it is possible to provide a highly efficient projector with excellent display quality.

[0073] Second embodiment The wavelength converter of the second embodiment will be described below. The basic configuration of the wavelength converter of the second embodiment is similar to that of the first embodiment, but the configuration of the bonding layer is different from that of the first embodiment, so the following description will mainly focus on the configuration of the bonding layer.

[0074] Fig. 4 is an enlarged view showing the main configuration of a wavelength converter 120 of this embodiment. In Fig. 4, components common to the drawings used in the above embodiment are given the same reference numerals, and description thereof will be omitted. As shown in FIG. 4, the wavelength converter 120 includes a rotation driver 21, a wheel substrate 22, a phosphor 23, a heat dissipation member 24, and a bonding layer 125.

[0075] The bonding layer 125 of the present embodiment includes an adhesive 27 and a plurality of first fillers 128 mixed in the adhesive 27. Each of the plurality of first fillers 128 has a rod-like shape having a longitudinal axis Lx.

[0076] The plurality of first fillers 128 are erected on the surface 22a of the wheel substrate 22 or the back surface 23b of the phosphor 23 facing the wheel substrate 22. In the present embodiment, the plurality of first fillers 128 are arranged, for example, by electrostatic flocking processing, so that the longitudinal axis Lx is substantially perpendicular to the surface 22a and the back surface 23b. In the present embodiment, the lengths of the first fillers 128 are substantially equal. Specifically, the length of the first fillers 128 is made to coincide with the thickness of the adhesive 27.

[0077] According to the wavelength converter 120 of the present embodiment, the length of the heat path HC by the first filler 128 formed in the bonding layer 125 can be minimized. In addition, by making the lengths of the first fillers 128 approximately equal, the thickness of the adhesive 27 can be controlled by the length of the first fillers 128. By making the thickness of the bonding layer 125 uniform in this way, the phosphor 23 can be stably held and the variation in heat dissipation property within the surface of the phosphor 23 can be suppressed.

[0078] Third embodiment The wavelength converter of the third embodiment will be described below. The basic configuration of the wavelength converter of the third embodiment is similar to that of the first embodiment, but the configuration of the bonding layer is different from that of the first embodiment, so the following description will mainly focus on the configuration of the bonding layer.

[0079] Fig. 5 is an enlarged view showing the main configuration of a wavelength converter 220 of this embodiment. In Fig. 5, components common to the drawings used in the above embodiment are given the same reference numerals, and description thereof will be omitted. As shown in FIG. 5, the wavelength converter 220 includes a rotation driver 21, a wheel substrate 22, a phosphor 23, a heat dissipation member 24, and a bonding layer 225.

[0080] The bonding layer 225 of the present embodiment includes an adhesive 27, a plurality of first fillers 228, and a plurality of second fillers 229 having a higher reflectance than the first fillers 228. The plurality of second fillers 229 are spherical in shape.

[0081] The multiple first fillers 228 each have a rod-like shape, and like the first fillers 28 of the first embodiment, are mixed in the adhesive 27 in a state inclined rather than parallel to the surface 22a of the wheel substrate 22. The multiple first fillers 228 are folded many times within the adhesive 27 to form a fibrous shape as a whole.

[0082] In the present embodiment, the material of the first filler 228 can be a material with high thermal conductivity, such as carbon or carbon nanotubes shown in Table 1. Carbon and carbon nanotubes have very high thermal conductivity, but are black in color and absorb light, resulting in a low reflectance of 5% or less. Therefore, while the first filler 228 increases the thermal conductivity of the bonding layer 225, it also becomes a factor in reducing light reflectivity.

[0083] In contrast, in the case of this embodiment, the material of the second filler 229 can be a material with high reflectivity, such as titanium oxide, alumina (Al2O3), or zinc oxide, as shown in Table 1. The multiple second fillers 229 are spherical in shape. By mixing the spherical second filler 229 in this manner, light can be reflected in various directions, and the light reflectance inside the bonding layer 225 can be further improved. Any of the multiple second fillers 229 is disposed in the adhesive 27 so as to be in contact with the first filler 228. In the bonding layer 225 of this embodiment, the first filler 228 and the second filler 229 are in contact with each other, which facilitates the formation of a heat path in the thickness direction. Note that, as the material of the second filler 229, for example, beryllium oxide (BeO), which has light reflectivity and high thermal conductivity of 250 W / m·K, may be used.

[0084] In the bonding layer 225 of this embodiment, the content of the first filler 228 is lower than the content of the second filler 229. The content of the first filler 228 in the entire bonding layer 225 is preferably 40 vol% or less, and the total filling amount of the first filler 228 and the second filler 229 in the entire bonding layer 225 is preferably 80 vol% or less. By mixing the first filler 228 and the second filler 229 at such a ratio, a bonding layer 225 that has excellent thermal conductivity and light reflectivity and sufficient bonding strength can be realized.

[0085] Thus, according to the wavelength converter 220 of this embodiment, the heat path HC is secured by the multiple first fillers 228 with excellent thermal conductivity, while the second fillers 229 with high reflectance are mixed in to increase the efficiency of extracting the fluorescence Y. Therefore, according to the wavelength converter 220 of this embodiment, bright illumination light can be generated by efficiently extracting the fluorescence.

[0086] (Fourth embodiment) The wavelength converter of the fourth embodiment will be described below. The basic configuration of the wavelength converter of the fourth embodiment is similar to that of the third embodiment, but the configuration of the bonding layer is different from that of the third embodiment, so the following description will mainly focus on the configuration of the bonding layer.

[0087] Fig. 6 is an enlarged view showing the main configuration of a wavelength converter 320 of this embodiment. In Fig. 6, components common to the drawings used in the above-mentioned embodiment are given the same reference numerals, and description thereof will be omitted. As shown in FIG. 6, the wavelength converter 320 includes a rotation driver 21, a wheel substrate 22, a phosphor 23, a heat dissipation member 24, and a bonding layer 325.

[0088] The bonding layer 325 of the present embodiment includes an adhesive 27, a plurality of first fillers 228, and a plurality of second fillers 329 having a higher reflectance than the first fillers 228. The plurality of second fillers 329 are spherical in shape.

[0089] In this embodiment, the outer diameter of the second filler 329 is equal to the thickness of the bonding layer 325. The second filler 329 is sandwiched between the rear surface 23b of the phosphor 23 and the reflecting surface 26a.

[0090] According to the wavelength conversion device 320 of this embodiment, the outer diameter of the second filler 329 is set to be equal to the thickness of the bonding layer 325, so that the thickness of the adhesive 27 can be controlled to a desired value by bonding the bonding layer 325 while pressurizing the phosphor 23.

[0091] Fifth embodiment The wavelength converter of the fifth embodiment will be described below. The basic configuration of the wavelength converter of the fifth embodiment is similar to that of the first embodiment, but the configuration of the bonding layer is different from that of the first embodiment, so the following description will mainly focus on the configuration of the bonding layer.

[0092] Fig. 7 is an enlarged view showing the main configuration of a wavelength converter 420 of this embodiment. In Fig. 7, components common to the drawings used in the above embodiment are given the same reference numerals, and description thereof will be omitted. As shown in FIG. 7, the wavelength converter 420 has a rotation driver 21, a wheel substrate 22, a phosphor 23, a heat dissipation member 24, and a bonding layer 425.

[0093] The bonding layer 425 of this embodiment includes an adhesive 27, a plurality of first fillers 428, and a plurality of second fillers 429 having a reflectance higher than that of the first fillers 28. The shape of the plurality of second fillers 429 is rod-like, similar to that of the first fillers 28. In other words, the second fillers 429 have a longitudinal axis along the longitudinal direction.

[0094] Examples of materials that can be used for such rod-shaped second fillers 429 with excellent reflectivity include titanium oxide, alumina (Al2O3), and beryllium oxide (BeO), which has excellent light reflectivity and high thermal conductivity, as shown in Table 1. The multiple second fillers 429 are disposed in the adhesive 27 so as to be in contact with any of the multiple first fillers 428.

[0095] Furthermore, the second fillers 429 may have a fibrous shape as a whole by being folded over and over again within the adhesive 27. When the second fillers 429 have a fibrous shape in this manner, the thermal conductivity of the bonding layer 425 can be further improved by using a part of the second fillers 429 as a heat path.

[0096] Thus, according to the wavelength converter 420 of this embodiment, the first filler 428 with excellent thermal conductivity ensures a heat path, while the second filler 429 with excellent light reflectivity and thermal conductivity is mixed in, thereby making it possible to further increase the efficiency of extracting the fluorescence Y. Therefore, according to the wavelength converter 420 of this embodiment, even when the rod-shaped or fibrous first filler 428 and second filler 429 are used, it is possible to generate bright illumination light by efficiently extracting the fluorescence.

[0097] Sixth embodiment The wavelength converter of the sixth embodiment will be described below. The basic configuration of the wavelength converter of the sixth embodiment is similar to that of the first embodiment, but the configuration of the bonding layer is different from that of the first embodiment, so the following description will mainly focus on the configuration of the bonding layer.

[0098] Fig. 8 is an enlarged view showing the main configuration of a wavelength converter 520 of this embodiment. In Fig. 8, components common to those in the drawings used in the above-mentioned embodiment are given the same reference numerals, and description thereof will be omitted. As shown in FIG. 8, the wavelength converter 520 includes a rotation driver 21, a wheel substrate 22, a phosphor 523, a heat dissipation member 24, and a bonding layer 525.

[0099] The phosphor 523 of this embodiment has a structure in which a plurality of phosphor particles 523b are dispersed in a binder 523a, unlike the phosphor 23 made of a ceramic phosphor of the above embodiment. The binder 523a is made of a resin. The phosphor particles 523b are made of, for example, YAG:Ce particles.

[0100] The bonding layer 525 of this embodiment includes an adhesive 27 and a plurality of first fillers 528 mixed in the adhesive 27. Each of the plurality of first fillers 528 has a plate-like shape. In this embodiment, the plurality of first fillers 528 includes a filler 528a in contact with the phosphor 523 and a filler 528b in contact with the wheel substrate 22. Some of the plurality of first fillers 528 are arranged so as to be in contact with each other in the thickness direction of the adhesive 27. In this manner, the plurality of first fillers 528 form a heat path HC inside the bonding layer 525 that transfers heat of the phosphor 523 to the wheel substrate 22.

[0101] In the wavelength converter 520 of this embodiment, the phosphor 523 is not a ceramic phosphor, but has a structure in which phosphor particles 523b are dispersed in a binder 523a made of resin. In this embodiment, the gas barrier property of the phosphor 523 is lower than that of the other embodiments, so that there is a risk that air that has permeated the binder 523a may enter the bonding layer 525. For example, when the Ag film constituting the reflective layer 26 reacts with sulfur dioxide contained in the air, it turns black and the reflectance decreases.

[0102] In contrast, the wavelength converter 520 of the present embodiment can improve the gas barrier properties that suppress the intrusion of the gas GA into the reflective layer 26 made of an Ag film by coating the reflective layer 26 with a bonding layer 525 in which a plurality of plate-shaped first fillers 528 are mixed in the adhesive 27. This can suppress the decrease in reflectance caused by discoloration of the reflective layer 26 and realize a highly reliable wavelength converter that extracts bright fluorescence for a long period of time.

[0103] Seventh embodiment The wavelength converter of the seventh embodiment will be described below. The basic configuration of the wavelength converter of the seventh embodiment is similar to that of the first embodiment, but the configuration of the bonding layer is different from that of the first embodiment, so the following description will mainly focus on the configuration of the bonding layer.

[0104] Fig. 9 is an enlarged view showing the main configuration of a wavelength converter 620 of this embodiment. In Fig. 9, components common to the drawings used in the above-mentioned embodiment are given the same reference numerals, and description thereof will be omitted. As shown in FIG. 9, the wavelength converter 620 includes a rotation driver 21, a wheel substrate 22, a phosphor 23, a heat dissipation member 24, a bonding layer 25, and a heat diffusion member 30. The heat dissipation member 24 is a heat sink.

[0105] The heat diffusion member 30 is disposed on the rear surface 22b of the wheel substrate 22, and receives heat from the wheel substrate 22. The wavelength converter 620 of this embodiment has a phosphor support portion 50 constituted by the heat diffusion member 30 and the wheel substrate 22.

[0106] In this embodiment, the heat dissipation member 24 is provided on the heat diffusion member 30 of the phosphor support portion 50, and dissipates heat from the wheel substrate 22 by improving the heat diffusion performance of the heat diffusion member 30 by releasing heat from the heat diffusion member 30.

[0107] The heat diffusion member 30 is a so-called vapor chamber, and includes a heat receiving plate 31 that supports the rear surface 22b of the wheel substrate 22, and a heat dissipation plate 32 provided on the opposite side of the heat receiving plate 31. The heat diffusion member 30 includes a heat receiving section 31a that receives heat from the wheel substrate 22, a heat dissipation section 32a that dissipates the heat received by the heat receiving section 31a to the heat dissipation member 24, and an accommodation chamber SP that accommodates the working fluid L as a refrigerant in a sealed state.

[0108] The heat receiving portion 31a is provided on the surface of the heat receiving plate 31 opposite to the accommodation chamber SP. The heat receiving portion 31a vaporizes the liquid working fluid L by the heat of the rear surface 22b of the wheel substrate 22. The heat dissipation section 32a is provided on the surface of the heat dissipation plate 32 opposite to the accommodation chamber SP. The heat dissipation section 32a dissipates heat from the gaseous working fluid L flowing inside the accommodation chamber SP, thereby condensing the gaseous working fluid L and returning it to a liquid working fluid L. A heat dissipation member 24 is provided on a portion of the outer surface of the heat dissipation plate 32 corresponding to the heat dissipation section 32a.

[0109] In this embodiment, the thermal conductivity of the phosphor support part 50 including the vapor chamber is very high at 20,000 W / m K. Therefore, the thermal conductivity of the phosphor support part 50 is higher than the thermal conductivity of the first filler 28 mixed in the bonding layer 25. Therefore, the heat of the bonding layer 25 is efficiently transferred to the phosphor support part 50.

[0110] According to the wavelength conversion device 620 of the present embodiment, since it is provided with the phosphor support part 50 having a higher thermal conductivity than the first filler 28, it is possible to efficiently cool the phosphor 23, thereby improving the wavelength conversion efficiency and generating brighter fluorescence.

[0111] The technical scope of the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention. The reflecting layer 26 may not be provided, and the reflecting layer may be formed only of a bonding layer having a filler with reflecting properties. In addition, the specific description of the shape, number, arrangement, material, etc. of each component of the wavelength conversion device, the light source device, and the projector is not limited to the above embodiment and can be changed as appropriate. In the above embodiment, the projector of the present invention is applied to a projector using a liquid crystal light valve, but is not limited to this. The projector of the present invention may be applied to a configuration using a digital micromirror device as a light modulation device. In addition, the projector does not need to have multiple light modulation devices, and may have only one light modulation device.

[0112] In the above embodiment, the surface of the first filler may be coated with a film having light reflectivity by, for example, painting, plating, vapor deposition, or the like. Furthermore, the wavelength conversion device in the above embodiment is a reflective wavelength conversion device that emits fluorescence toward the incident side of the excitation light, but the present invention is also applicable to a transmissive wavelength conversion device that emits fluorescence in the direction opposite to the incident side of the excitation light. In addition, the wavelength conversion device in the above embodiment is an example of a rotational type in which the incident position of the excitation light on the phosphor changes over time by rotating the wheel substrate, but the wavelength conversion device may also be applied to a solid-state type wavelength conversion device in which the incident position of the excitation light on the phosphor does not change over time.

[0113] The following is a summary of this disclosure. (Appendix 1) A phosphor that is irradiated with excitation light; a substrate having a first surface; a bonding layer that bonds the phosphor to the first surface of the substrate, The bonding layer includes an adhesive and a plurality of first fillers mixed in the adhesive and having a longitudinal axis; the plurality of first fillers are positioned in a direction along the longitudinal axis that intersects with the first surface of the substrate; The thermal conductivity of the first filler is higher than the thermal conductivity of the adhesive. A wavelength conversion device characterized by:

[0114] According to the wavelength conversion device of Appendix 1, a heat path from the phosphor to the wheel substrate can be formed in the bonding layer by the multiple first fillers. If a heat path is formed in the bonding layer by increasing the filling rate of the spherical fillers as in the conventional technology, the amount of adhesive decreases, which reduces the adhesive strength of the bonding layer, and there is a risk of peeling or damage to the phosphor. In contrast, in the configuration of Appendix 1, the longitudinal axis of the first filler is oriented along the thickness direction of the bonding layer, thereby efficiently forming a thermal path, and therefore sufficient bonding strength can be obtained without reducing the amount of adhesive. Therefore, according to this configuration, the phosphor can be stably held and efficiently cooled, thereby increasing the wavelength conversion efficiency of the phosphor and generating bright fluorescent light.

[0115] (Appendix 2) The plurality of first fillers include a filler in contact with the phosphor and a filler in contact with the substrate. 2. A wavelength conversion device according to claim 1.

[0116] According to the configuration of Supplementary Note 2, a heat path from the phosphor to the wheel substrate can be easily formed by the multiple first fillers.

[0117] (Appendix 3) The plurality of first fillers are provided upright on the first surface of the substrate or on a surface of the phosphor facing the substrate. 3. A wavelength converter according to claim 1 or 2,

[0118] According to the configuration of Supplementary Note 3, the length of the heat path formed by the first filler in the bonding layer can be minimized. In addition, the thickness of the adhesive can be controlled by making the length of each first filler approximately equal. By making the thickness of the bonding layer uniform in this way, the phosphor can be stably held and the variation in heat dissipation property within the surface of the phosphor can be suppressed.

[0119] (Appendix 4) a heat diffusion member disposed on a second surface of the substrate opposite to the first surface and configured to receive heat from the substrate; the thermal conductivity of the phosphor support portion formed of the heat diffusion member and the substrate is higher than the thermal conductivity of the first filler; 4. A wavelength conversion device according to claim 1, wherein:

[0120] According to the configuration of Supplementary Note 4, since the phosphor support part has a higher thermal conductivity than the first filler, the phosphor can be efficiently cooled to increase the wavelength conversion efficiency and generate brighter fluorescent light.

[0121] (Appendix 5) The substrate is in contact with the bonding layer and has a reflective surface that reflects light. 5. A wavelength converter according to claim 1, wherein:

[0122] According to the configuration of Supplementary Note 5, the efficiency of extracting light from the phosphor can be further improved.

[0123] (Appendix 6) The reflectance of the first filler is higher than the reflectance of the adhesive. 6. A wavelength converter according to claim 1,

[0124] According to the configuration of Supplementary Note 6, the first filler not only constitutes a heat path but also reflects the fluorescence together with the reflective surface, thereby making it possible to increase the efficiency of extracting the fluorescence.

[0125] (Appendix 7) The bonding layer further includes a plurality of second fillers having a higher reflectivity than the plurality of first fillers. 7. A wavelength converter according to claim 1, wherein:

[0126] According to the configuration of Supplementary Note 7, while a heat path is ensured by a plurality of first fillers, the efficiency of extracting fluorescent light can be increased by mixing a plurality of second fillers having high reflectance. Therefore, brighter illumination light can be generated by extracting fluorescent light efficiently.

[0127] (Appendix 8) The shape of the plurality of second fillers is spherical. 8. A wavelength converter according to claim 7.

[0128] According to the configuration of Appendix 8, by mixing the spherical second filler, it becomes possible to reflect light in various directions, so that the light reflectance inside the bonding layer can be further improved.

[0129] (Appendix 9) In the bonding layer, the content of the first filler is lower than the content of the second filler. 9. The wavelength converter according to claim 7 or 8,

[0130] According to the configuration of Supplementary Note 9, a bonding layer having excellent thermal conductivity and light reflectivity and sufficient bonding strength can be realized.

[0131] (Appendix 10) The outer diameter of the second filler is equal to the thickness of the bonding layer. 9. The wavelength converter according to claim 7 or 8,

[0132] According to the configuration of Supplementary Note 10, by bonding the bonding layer in a state where the phosphor is pressurized, the thickness of the adhesive can be controlled to a desired value.

[0133] (Appendix 11) The second filler is shaped to have a longitudinal axis; 11. A wavelength converter according to any one of claims 7 to 10,

[0134] According to the configuration of Supplementary Note 11, while a heat path is ensured by the first filler having excellent thermal conductivity, the fluorescence extraction efficiency can be further increased by mixing the second filler having excellent light reflectivity and thermal conductivity.

[0135] (Appendix 12) Further, a heat dissipation member is provided on a second surface side of the substrate opposite to the first surface, and dissipates heat from the substrate. 12. A wavelength converter according to any one of claims 1 to 11,

[0136] According to the configuration of Supplementary Note 12, the cooling efficiency of the phosphor can be improved by the heat dissipation member.

[0137] (Appendix 13) the substrate is a wheel substrate; Further comprising a rotation drive unit that rotates the wheel substrate. 13. A wavelength converter according to any one of claims 1 to 12,

[0138] According to the configuration of Supplementary Note 13, since the phosphor rotates together with the wheel substrate, the incident position of the excitation light on the phosphor can be moved over time. Therefore, by improving the cooling performance of the phosphor, it is possible to suppress the decrease in the fluorescence conversion efficiency caused by the increase in the temperature of the phosphor.

[0139] (Appendix 14) A phosphor that is irradiated with excitation light; a substrate having a first surface; a bonding layer that bonds the phosphor to the first surface of the substrate, The bonding layer is composed of an adhesive and a plurality of first fillers having at least one of a fiber shape, a rod shape, and a plate shape mixed in the adhesive, The thermal conductivity of the first filler is higher than the thermal conductivity of the adhesive; The plurality of first fillers form a thermal path for transferring heat of the phosphor to the substrate. A wavelength conversion device characterized by:

[0140] According to the configuration of Appendix 14, a plurality of first fillers having at least one of a fibrous, rod-like, and plate-like shape efficiently form a thermal path within the bonding layer, so that sufficient bonding strength can be obtained without reducing the amount of adhesive as occurs when spherical fillers are used. Therefore, according to this configuration, the phosphor can be stably held and efficiently cooled, thereby increasing the wavelength conversion efficiency of the phosphor and generating bright fluorescent light.

[0141] (Appendix 15) The plurality of first fillers include a filler in contact with the phosphor and a filler in contact with the substrate. 15. The wavelength converter according to claim 14,

[0142] According to the configuration of appendix 15, a heat path from the phosphor to the wheel substrate can be easily formed by the multiple first fillers.

[0143] (Appendix 16) The plurality of first fillers are provided upright on the first surface of the substrate or on a surface of the phosphor facing the substrate. 16. The wavelength converter according to claim 14 or 15,

[0144] According to the configuration of appendix 16, the length of the heat path formed by the first filler in the bonding layer can be minimized. In addition, the thickness of the adhesive can be controlled by making the length of each first filler approximately equal. By making the thickness of the bonding layer uniform in this way, the phosphor can be stably held and the variation in heat dissipation property within the surface of the phosphor can be suppressed.

[0145] (Appendix 17) a heat diffusion member disposed on a second surface of the substrate opposite to the first surface and configured to receive heat from the substrate; the thermal conductivity of the phosphor support portion formed of the heat diffusion member and the substrate is higher than the thermal conductivity of the first filler; 17. A wavelength converter according to any one of claims 14 to 16,

[0146] According to the configuration of Supplementary Note 17, since the phosphor support part has a higher thermal conductivity than the first filler, the phosphor can be efficiently cooled to increase the wavelength conversion efficiency and generate brighter fluorescent light.

[0147] (Appendix 18) The substrate is in contact with the bonding layer and has a reflective surface that reflects light. 18. A wavelength converter according to any one of claims 14 to 17,

[0148] According to the configuration of appendix 18, the efficiency of extracting light from the phosphor can be further improved.

[0149] (Appendix 19) The reflectance of the first filler is higher than the reflectance of the adhesive. 19. A wavelength converter according to any one of claims 14 to 18,

[0150] According to the configuration of Supplementary Note 19, the first filler not only constitutes a heat path but also reflects the fluorescence together with the reflective surface, thereby increasing the efficiency of extracting the fluorescence.

[0151] (Appendix 20) The bonding layer further includes a plurality of second fillers having a higher reflectivity than the plurality of first fillers. 20. A wavelength converter according to claim 14, wherein:

[0152] According to the configuration of Supplementary Note 20, while a heat path is ensured by a plurality of first fillers, the efficiency of extracting fluorescent light can be increased by mixing a plurality of second fillers having high reflectance. Therefore, brighter illumination light can be generated by extracting fluorescent light efficiently.

[0153] (Appendix 21) The shape of the plurality of second fillers is spherical. 21. The wavelength converter according to claim 20,

[0154] According to the configuration of Supplementary Note 21, by mixing the spherical second filler, it becomes possible to reflect light in various directions, so that the light reflectance inside the bonding layer can be further improved.

[0155] (Appendix 22) In the bonding layer, the content of the first filler is lower than the content of the second filler. 22. The wavelength converter according to claim 20 or 21,

[0156] According to the configuration of Supplementary Note 22, a bonding layer having excellent thermal conductivity and light reflectivity and sufficient bonding strength can be realized.

[0157] (Appendix 23) The outer diameter of the second filler is equal to the thickness of the bonding layer. 22. The wavelength converter according to claim 20 or 21,

[0158] According to the configuration of Addendum 23, the adhesive thickness can be controlled to a desired value by bonding the bonding layer while the phosphor is being pressed.

[0159] (Appendix 24) The second filler is shaped to have a longitudinal axis; 24. The wavelength converter according to claim 20, wherein

[0160] According to the configuration of Addendum 24, while a heat path is secured by the first filler having excellent thermal conductivity, the efficiency of extracting fluorescence can be further increased by mixing the second filler having excellent light reflectivity and thermal conductivity.

[0161] (Appendix 25) Further, a heat dissipation member is provided on a second surface side of the substrate opposite to the first surface, and dissipates heat from the substrate. 25. A wavelength converter according to any one of claims 14 to 24,

[0162] According to the configuration of appendix 25, the cooling efficiency of the phosphor can be improved by the heat dissipation member.

[0163] (Appendix 26) the substrate is a wheel substrate; Further comprising a rotation drive unit that rotates the wheel substrate. 26. A wavelength converter according to any one of claims 14 to 25,

[0164] According to the configuration of Supplementary Note 26, since the phosphor rotates together with the wheel substrate, the incident position of the excitation light on the phosphor can be moved over time. Therefore, by improving the cooling performance of the phosphor, it is possible to suppress the decrease in the fluorescence conversion efficiency caused by the increase in the temperature of the phosphor.

[0165] (Appendix 27) A wavelength converter according to any one of claims 1 to 26, An excitation light source that emits the excitation light toward the wavelength conversion device. A light source device characterized by:

[0166] According to the light source device having the configuration of Supplementary Note 27, it is possible to provide a light source device that has excellent wavelength conversion efficiency and emits illumination light containing bright fluorescent light.

[0167] (Appendix 28) A light source device according to claim 27; a light modulation device that modulates the light emitted from the light source device; a projection optical device that projects the light modulated by the light modulation device; Equipped with A projector characterized by:

[0168] According to the projector having the configuration of Supplementary Note 28, a highly efficient projector with excellent display quality can be provided. [Explanation of symbols]

[0169] 1...projector, 2...light source device, 4B, 4G, 4R...light modulation device, 6...projection optical device, 20,120,220,320,420,520,620...wavelength conversion device, 21...rotation drive unit, 22...wheel substrate, 23,523...phosphor, 24...heat dissipation member, 25,125,225,325,425,525...bonding layer, 26a...reflective surface, 27...adhesive, 28,128,228,428,528...first filler, 28a,528a...filler (in contact with phosphor), 28b,528b...filler (in contact with substrate), 29,229,329,429...second filler, 30...thermal diffusion member, 50...phosphor support unit, E...excitation light, Lx...longitudinal axis, Y...fluorescence, WL...illumination light.

Claims

1. A phosphor that is irradiated with excitation light; a substrate having a first surface; a bonding layer that bonds the phosphor to the first surface of the substrate, The bonding layer includes an adhesive and a plurality of first fillers mixed in the adhesive and having a longitudinal axis; the plurality of first fillers are positioned such that a direction along the longitudinal axis intersects with the first surface of the substrate; The thermal conductivity of the first filler is higher than the thermal conductivity of the adhesive. A wavelength conversion device characterized by:

2. The plurality of first fillers include a filler in contact with the phosphor and a filler in contact with the substrate.

2. The wavelength conversion device according to claim 1 .

3. The plurality of first fillers are provided upright on the first surface of the substrate or on a surface of the phosphor facing the substrate.

3. The wavelength conversion device according to claim 1 or 2.

4. a heat diffusion member disposed on a second surface of the substrate opposite to the first surface and configured to receive heat from the substrate; the thermal conductivity of the phosphor support portion formed of the heat diffusion member and the substrate is higher than the thermal conductivity of the first filler; 3. The wavelength conversion device according to claim 1 or 2.

5. The substrate is in contact with the bonding layer and has a reflective surface that reflects light.

3. The wavelength conversion device according to claim 1 or 2.

6. The reflectance of the first filler is higher than the reflectance of the adhesive.

6. The wavelength conversion device according to claim 5.

7. The reflectance of the first filler is higher than the reflectance of the adhesive.

3. The wavelength conversion device according to claim 1 or 2.

8. The bonding layer further includes a plurality of second fillers having a reflectance higher than that of the plurality of first fillers.

3. The wavelength conversion device according to claim 1 or 2.

9. The shape of the plurality of second fillers is spherical.

9. A wavelength conversion device according to claim 8.

10. In the bonding layer, the content of the first filler is lower than the content of the second filler.

9. A wavelength conversion device according to claim 8.

11. The outer diameter of the second filler is equal to the thickness of the bonding layer.

10. The wavelength conversion device according to claim 9.

12. The second filler is shaped to have a longitudinal axis.

9. A wavelength conversion device according to claim 8.

13. a heat dissipation member disposed on a second surface side of the substrate opposite to the first surface and configured to dissipate heat from the substrate; 3. The wavelength conversion device according to claim 1 or 2.

14. the substrate is a wheel substrate; Further comprising a rotation drive unit that rotates the wheel substrate.

3. The wavelength conversion device according to claim 1 or 2.

15. A phosphor that is irradiated with excitation light; a substrate having a first surface; a bonding layer that bonds the phosphor to the first surface of the substrate, The bonding layer is composed of an adhesive and a plurality of first fillers having at least one of a fiber shape, a rod shape, and a plate shape mixed in the adhesive, The thermal conductivity of the first filler is higher than the thermal conductivity of the adhesive; The plurality of first fillers form a thermal path for transferring heat of the phosphor to the substrate. A wavelength conversion device characterized by:

16. A wavelength conversion device according to claim 1 or 2, An excitation light source that irradiates the excitation light toward the wavelength conversion device. A light source device characterized by:

17. The light source device according to claim 16 ; a light modulation device that modulates the light emitted from the light source device; a projection optical device that projects the light modulated by the light modulation device; Equipped with A projector characterized by:

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