Wavelength conversion element, method of manufacturing wavelength conversion element, light source device, and projector

Abstract

A wavelength conversion element having desired optical characteristics by suppressing deterioration of a reflective film due to heat, a method for manufacturing a wavelength conversion element, a light source device, and a projector are provided. [Solution] The wavelength conversion element of the present invention comprises a wavelength conversion layer that converts incident first light into second light of a wavelength band different from the first light, a substrate on which the wavelength conversion layer is provided, and a reflective film that is provided between the substrate and the wavelength conversion layer and reflects the second light, wherein the wavelength conversion layer includes a translucent resin, translucent particles, and phosphor particles, and the translucent resin fills the gaps between the translucent particles and the phosphor particles.

Description

[Technical Field]

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

[0002] In a method for manufacturing a wavelength conversion element disclosed in Patent Document 1, a mixture of phosphor particles and a binder containing glass is applied to a substrate, and then the mixture is fired to form a wavelength conversion layer on the substrate. In this manufacturing method, the firing step of the mixture is performed at a temperature higher than the softening point of the glass. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2020-154032 Summary of the Invention [Problem to be solved by the invention]

[0004] In the above manufacturing method, when a dielectric multilayer film, for example, is formed as a reflective film between the substrate and the wavelength conversion layer in order to improve the light utilization efficiency of the fluorescence, the dielectric multilayer film is deteriorated by heat in the baking process of the mixture, resulting in a problem that desired optical properties cannot be obtained. [Means for solving the problem]

[0005] In order to solve the above problems, according to a first aspect of the present invention, there is provided a wavelength conversion element comprising: a wavelength conversion layer that converts incident first light into second light of a wavelength band different from the first light; a substrate on which the wavelength conversion layer is provided; and a reflective film that is provided between the substrate and the wavelength conversion layer and reflects the second light, wherein the wavelength conversion layer contains a translucent resin, translucent particles, and phosphor particles, and the translucent resin fills gaps between the translucent particles and the phosphor particles.

[0006] According to a second aspect of the present invention, there is provided a method for manufacturing a wavelength conversion element, comprising the steps of: forming a reflective film on a substrate; applying a first material containing a light-transmitting resin and light-transmitting particles onto the reflective film, and applying a second material containing the light-transmitting resin and phosphor particles onto the first material; and forming a wavelength conversion layer on the reflective film by hardening the first material and the light-transmitting resin contained in the second material without melting the light-transmitting particles contained in the first material.

[0007] According to a third aspect of the present invention, there is provided a light source device comprising: the wavelength conversion element of the first aspect; and a light source that emits the first light to the wavelength conversion element.

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

[0009] [Figure 1] FIG. 1 is a schematic configuration diagram illustrating a projector. [Figure 2] FIG. 2 is a schematic diagram showing the configuration of a light source device 2. [Figure 3] FIG. 2 is a cross-sectional view showing the configuration of a wavelength conversion element. [Figure 4A] 1A to 1C are diagrams illustrating a manufacturing process of a wavelength conversion element. [Figure 4B] 1A to 1C are diagrams illustrating a manufacturing process of a wavelength conversion element. [Figure 4C] 1A to 1C are diagrams illustrating a manufacturing process of a wavelength conversion element. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, embodiments 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 portions enlarged for convenience in order to make the characteristics easier to understand, and the dimensional proportions of each component may not necessarily be the same as those in reality.

[0011] FIG. 1 is a schematic configuration diagram showing 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 combining 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 that has passed 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 that has passed through the second dichroic mirror 7b toward 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 is disposed between the second dichroic mirror 7b and the second total reflection mirror 8b in the optical path of the blue light LB. The second relay lens 9b is disposed between the second total reflection mirror 8b and the third total reflection mirror 8c in the optical path of the blue light LB. The first relay lens 9a and the second relay lens 9b compensate for 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] Each of the light modulation devices 4R, 4G, and 4B uses, for example, a transmissive liquid crystal panel. Polarizing plates (not shown) are arranged on 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 with reference to Fig. 2. Fig. 2 is a schematic diagram showing the configuration of the light source device 2 of this embodiment. As shown in FIG. 2, the light source device 2 includes a light source 10, an afocal optical system 11, a homogenizer optical system 12, a focusing optical system 13, a wavelength conversion element 20, a pickup optical system 30, and a uniform illumination optical system 40.

[0023] The light source 10 is composed of multiple semiconductor lasers 10a that emit blue excitation light E composed of laser light, and multiple collimator lenses 10b. The multiple semiconductor lasers 10a are arranged in an array in a plane perpendicular to the illumination optical axis 100ax. The collimator lenses 10b are arranged in an array in a plane perpendicular to the illumination optical axis 100ax so as to correspond to each semiconductor laser 10a. The collimator lenses 10b convert the excitation light E emitted from the semiconductor lasers 10a corresponding to the collimator lenses 10b into parallel light. The excitation light E in this embodiment corresponds to an example of the "first light" in the present invention.

[0024] The afocal optical system 11 includes, for example, a convex lens 11a and a concave lens 11b, and reduces the beam diameter of the excitation light E emitted from the light source 10 as a parallel beam.

[0025] The homogenizer optical system 12 includes, for example, a first multi-lens array 12a and a second multi-lens array 12b. The homogenizer optical system 12 uniformly distributes the light intensity of the excitation light on the phosphor layer 21 of the wavelength conversion element 20, i.e., forms a so-called top-hat distribution. The homogenizer optical system 12, together with the focusing optical system 13, superimposes the multiple small beams emitted from the multiple lenses of the first multi-lens array 12a and the second multi-lens array 12b on the phosphor layer 21 of the wavelength conversion element 20. This uniformly distributes the light intensity of the excitation light E irradiated onto the phosphor layer 21.

[0026] The focusing optical system 13 includes, for example, a first lens 13a and a second lens 13b. In this embodiment, the first lens 13a and the second lens 13b are each formed of a convex lens. The focusing optical system 13 is disposed in the optical path from the homogenizer optical system 12 to the wavelength conversion element 20, and focuses the excitation light E to make it incident on the phosphor layer 21 of the wavelength conversion element 20.

[0027] Next, the configuration of the wavelength conversion element 20 will be described. 3 is a cross-sectional view showing the configuration of the wavelength conversion element 20. Fig. 3 corresponds to a cross section of the wavelength conversion element 20 cut along a plane including the illumination optical axis 100ax in Fig. 2.

[0028] 3, the wavelength conversion element 20 of this embodiment includes a phosphor layer 21, a substrate 22, a dichroic film 23, and an anti-reflection film 24. In this embodiment, the phosphor layer 21 corresponds to an example of the "wavelength conversion layer" of the present invention, and the dichroic film 23 corresponds to an example of the "reflection film" of the present invention.

[0029] The substrate 22 has a first surface 22a on which the phosphor layer 21 is provided, and a second surface 22b opposite to the first surface 22a. The substrate 22 is made of a light-transmitting base material such as alumina, sapphire, or glass.

[0030] The dichroic film 23 is provided on the first surface 22a of the substrate 22. Specifically, the dichroic film 23 is provided between the substrate 22 and the phosphor layer 21. The dichroic film 23 is a dielectric multilayer film having optical properties of transmitting the excitation light E and reflecting the fluorescence Y. That is, the substrate 22 supports the phosphor layer 21 via the dichroic film 23 .

[0031] The excitation light E is incident on the substrate 22 from the second surface 22b opposite to the dichroic film 23. The antireflection film 24 is provided on the second surface 22b of the substrate 22. The antireflection film 24 is formed of, for example, an AR coating. The antireflection film 24 suppresses reflection of the excitation light E at the interface between the second surface 22b of the substrate 22 and the air layer. This allows the excitation light E to efficiently enter the substrate 22 from the second surface 22b via the antireflection film 24. Note that the antireflection film 24 is not an essential component of the wavelength conversion element 20 and may be omitted as necessary.

[0032] In the present embodiment, excitation light E is incident on phosphor layer 21 from rear surface 21a facing substrate 22, and fluorescence Y is emitted from front surface 21b. Phosphor layer 21 converts excitation light E in the blue wavelength band into fluorescence Y in a yellow wavelength band different from the blue wavelength band.

[0033] In the wavelength conversion element 20 of this embodiment, the phosphor layer 21 transmits and emits a portion of the excitation light E1 that has not been wavelength-converted, in addition to the fluorescence Y. This allows the wavelength conversion element 20 to emit white illumination light WL from the phosphor layer 21. The wavelength conversion element 20 of this embodiment is a transmissive wavelength conversion element that emits illumination light WL containing fluorescence Y from the front surface 21b opposite to the back surface 21a of the phosphor layer 21, where the excitation light E is incident.

[0034] The phosphor layer 21 includes a translucent resin 210 , a plurality of translucent particles 211 , and a plurality of phosphor particles 212 . The light-transmitting resin 210 is the main material of the binder of the phosphor layer 21 . The light-transmitting resin 210 may be, for example, a thermosetting resin such as a silicone resin or an epoxy resin, or a thermoplastic resin such as a polycarbonate. The light-transmitting resin 210 is cured in a state in which it fills the gaps between the light-transmitting resin 210 and the phosphor particles 212. Therefore, no air layer is present in the gaps between the light-transmitting resin 210 and the phosphor particles 212. The refractive index of the light-transmitting resin 210 is, for example, 1.4 to 1.6. The softening point of the light-transmitting resin 210 made of a thermoplastic resin is, for example, 100 to 300°C. The curing temperature of the light-transmitting resin 210 made of a thermosetting resin is, for example, 100 to 300°C.

[0035] The light-transmitting particles 211 are made of an inorganic material. For example, glass particles made of borosilicate glass, silica glass, etc. are used as the light-transmitting particles 211. The refractive index of the light-transmitting particles 211 is, for example, 1.4 to 1.6. The phosphor particles 212 are, for example, yttrium aluminum garnet (YAG (YAlO)) doped with cerium (Ce) as an activator. 12 ):Ce) The refractive index of the phosphor particles 212 is, for example, 1.8 to 1.85.

[0036] The light-transmitting particles 211 made of an inorganic material have higher heat resistance than the light-transmitting resin 210. For example, when the light-transmitting resin 210 is made of a thermoplastic resin, the softening point of the light-transmitting particles 211 may be set to a temperature higher than the softening point of the light-transmitting resin 210. With this configuration, the light-transmitting particles 211 are not deformed by heat even at the temperature when the light-transmitting resin 210 is melted.

[0037] Furthermore, when the light-transmitting resin 210 is made of a thermosetting resin, the hardening temperature of the light-transmitting resin 210 may be set to a temperature lower than the softening point of the light-transmitting particles 211. With this configuration, the light-transmitting particles 211 are not deformed by heat even when the light-transmitting resin 210 is thermally hardened.

[0038] For this reason, in the wavelength conversion element 20 of this embodiment, the light-transmitting particles 211 are in a particulate state, that is, they maintain a substantially spherical shape. Here, if the light-transmitting particles 211 do not retain their particle shape, this means that the light-transmitting particles 211 have melted due to the generation of heat of at least 500°C or more during the process of forming the phosphor layer 21. When heat of 500°C or more is generated in this manner, the dichroic film 23 provided below the phosphor layer 21 deteriorates, causing a problem that desired optical properties cannot be obtained.

[0039] In contrast, in the wavelength conversion element 20 of this embodiment, the translucent particles 211 do not deform due to heat and retain their particle shape, and since the translucent resin 210 is used as the main material of the binder, the dichroic film 23 provided below the phosphor layer 21 is less likely to deteriorate due to heat.

[0040] In the wavelength conversion element 20 of this embodiment, the refractive index of the light-transmitting particles 211 relative to the light-transmitting resin 210 is 85% or more and 115% or less. It is more preferable that the refractive index of the light-transmitting particles 211 relative to the light-transmitting resin 210 is 90% or more and 110% or less. With this configuration, the difference in refractive index between the light-transmitting resin 210 and the light-transmitting particles 211 is kept small, so that loss of light due to scattering and reflection at the interface between the light-transmitting resin 210 and the light-transmitting particles 211 can be reduced.

[0041] In this embodiment, the particle size of the light-transmitting particles 211 is smaller than that of the phosphor particles 212. Specifically, the average particle size of the plurality of light-transmitting particles 211 is, for example, 1 to 10 μm, and the average particle size of the plurality of phosphor particles 212 is, for example, 10 to 40 μm. Since the light-transmitting particles 211 have a particle size smaller than that of the phosphor particles 212, they enter the gaps between the phosphor particles 212 and are arranged in contact with or in close proximity to the phosphor particles 212.

[0042] According to this configuration, heat generated in the phosphor particles 212 when the fluorescence Y is produced is transferred to the light-transmitting particles 211 and released, so that a temperature rise in the phosphor layer 21 can be suppressed compared to a configuration in which only the light-transmitting resin 210 is used as a binder. Therefore, even when an inorganic material is not used as the main material of the binder, a temperature rise in the phosphor particles 212 can be suppressed. Furthermore, by making the particle size of the phosphor particles 212 relatively large, a sufficient amount of phosphor particles 212 can be contained in the phosphor layer 21, so that fluorescence Y with a desired brightness can be extracted as illumination light WL.

[0043] Furthermore, in the wavelength conversion element 20 of this embodiment, the content of the light-transmitting particles 211 in the phosphor layer 21 varies in the thickness direction of the phosphor layer 21. In this specification, the volume ratio of the light-transmitting particles 211 contained in the phosphor layer 21 is referred to as the “content of the light-transmitting particles 211.”

[0044] Specifically, in the thickness direction of the phosphor layer 21, the content of the light-transmitting particles 211 on the dichroic film 23 side is higher than the content of the light-transmitting particles 211 on the opposite side to the dichroic film 23. In other words, in the wavelength conversion element 20 of this embodiment, the light-transmitting particles 211 are mixed more in the phosphor layer 21 in the region closer to the dichroic film 23.

[0045] In the wavelength conversion element 20 of this embodiment, the excitation light E is transmitted through the substrate 22 and the dichroic film 23 in this order and is incident on the rear surface 21a of the phosphor layer 21. Therefore, a large amount of excitation light E is incident on the rear surface 21a of the phosphor layer 21, and the temperature rises due to the emission of fluorescence Y. On the other hand, the phosphor layer 21 has a characteristic that the conversion efficiency of fluorescence Y decreases when the temperature becomes too high.

[0046] In contrast, the phosphor layer 21 of this embodiment has a higher content of light-transmitting particles 211 on the dichroic film 23 side, i.e., on the back surface 21a side on which the excitation light E is incident. Therefore, the light-transmitting particles 211 can transfer heat from the phosphor particles 212 to the back surface 21a side of the phosphor layer 21 and release the heat to the substrate 22 via the dichroic film 23 with which the back surface 21a abuts. Therefore, according to the wavelength conversion element 20 of this embodiment, the heat dissipation property of the phosphor layer 21 can be improved.

[0047] Next, an example of a method for manufacturing the wavelength conversion element 20 will be described with reference to the drawings. 4A to 4C are diagrams showing the manufacturing process of the wavelength conversion element 20. As shown in FIG. 4A, in a first step, a dichroic film 23 is formed on a first surface 22a of a substrate 22, and an anti-reflection film 24 is formed on a second surface 22b of the substrate 22.

[0048] Next, a paste material containing the constituent material of the phosphor layer 21 is applied onto the dichroic film 23. In the case of this embodiment, the application of the paste material is carried out in two stages. 4B, a first material P1 containing a light-transmitting resin 210 and a plurality of light-transmitting particles 211, which are constituent materials of the phosphor layer 21, is applied onto the dichroic film 23, and a second material P2 containing a light-transmitting resin 210 and a plurality of phosphor particles 212, which are constituent materials of the phosphor layer 21, is applied onto the first material P1. The film thickness of the first material P1 is thinner than the film thickness of the second material P2.

[0049] Here, when the second material P2 is applied on top of the first material P1, the particles contained in the first material P1 and the second material P2 may be mixed with each other, but the first material P1 will contain more translucent particles 211 than the second material P2.

[0050] Next, as shown in FIG. 4C, the translucent resin 210 contained in the first material P1 and the second material P2 is hardened without melting the multiple translucent particles 211 contained in the first material P1, thereby forming a phosphor layer 21 on the dichroic film 23.

[0051] In the present embodiment, as described above, a thermoplastic resin may be used as the light-transmitting resin 210. In this case, the softening point of the light-transmitting particles 211 may be set to a temperature higher than the softening point of the light-transmitting resin 210. In this way, even when the first material P1 is formed by melting the light-transmitting resin 210, deformation of the light-transmitting particles 211 due to heat can be suppressed. When the translucent resin 210 is a thermoplastic resin, by cooling the first material P1 and the second material P2, respectively, the translucent resin 210 contained in the first material P1 and the second material P2 can be hardened without melting the translucent particles 211 contained in the first material P1, thereby forming the phosphor layer 21 on the dichroic film 23.

[0052] Alternatively, as described above, a thermosetting resin may be used as the light-transmitting resin 210. In this case, the hardening temperature of the light-transmitting resin 210 may be set to a temperature lower than the softening point of the light-transmitting particles 211. In this way, deformation of the light-transmitting particles 211 due to the temperature when the light-transmitting resin 210 contained in the first material P1 is thermally hardened can be suppressed. When the light-transmitting resin 210 is a thermosetting resin, applying heat of a predetermined temperature to the first material P1 and the second material P2 hardens the light-transmitting resin 210 contained in the first material P1 and the second material P2 without melting the light-transmitting particles 211 contained in the first material P1, thereby forming the phosphor layer 21 on the dichroic film 23. Note that the light-transmitting resins 210 contained in the first material P1 and the second material P2 are integrated with each other, resulting in a state in which there is no interface between them.

[0053] By the above-described manufacturing process, the wavelength conversion element 20 of this embodiment can be manufactured in which the closer to the dichroic film 23 the region of the phosphor layer 21 is, the more light-transmitting particles 211 are mixed in the phosphor layer 21.

[0054] In the above description, an example has been given in which the first material P1 and the second material P2 are successively applied and then cured together to form the phosphor layer 21. However, the phosphor layer 21 may also be formed by applying and curing the first material P1, and then applying and curing the second material P2 on the cured first material P1. In other words, the phosphor layer 21 may also be formed by curing the first material P1 and the second material P2 separately.

[0055] Alternatively, the phosphor layer 21 may be formed by stacking a second particle layer including a plurality of phosphor particles 212 on a first particle layer including a plurality of light-transmitting particles 211, arranging a light-transmitting resin 210 so as to fill the gaps between the light-transmitting particles 211 and the phosphor particles 212, and then curing the light-transmitting resin 210. The first particle layer can be formed, for example, by applying a material in which only the plurality of light-transmitting particles 211 are dispersed in a solvent onto the dichroic film 23 and then evaporating the solvent. Similarly, the second particle layer can be formed, for example, by applying a material in which only the plurality of phosphor particles 212 are dispersed in a solvent onto the first layer and then evaporating the solvent.

[0056] As shown in FIG. 2, the illumination light WL emitted from the wavelength conversion element 20 enters the pickup optical system 30. The pickup optical system 30 includes, for example, a first collimating lens 31 and a second collimating lens 32. The pickup optical system 30 is a collimating optical system that approximately collimates the illumination light WL emitted from the wavelength conversion element 20. The first collimating lens 31 and the second collimating lens 32 are each composed of a convex lens. The light collimated by the pickup optical system 30 enters the uniform illumination optical system 40.

[0057] The uniform illumination optical system 40 includes a first lens array 41, a second lens array 42, a polarization conversion element 43, and a superimposing lens 44.

[0058] The first lens array 41 has a plurality of first lenses 41a for dividing the illumination light WL from the light source device 2 into a plurality of partial light beams. The plurality of first lenses 41a are arranged in a matrix in a plane perpendicular to the illumination optical axis 100ax.

[0059] The second lens array 42 has a plurality of second lenses 42a corresponding to the plurality of first lenses 41a of the first lens array 41. The plurality of second lenses 42a are arranged in a matrix in a plane perpendicular to the illumination optical axis 100ax.

[0060] The second lens array 42, together with the superimposing lens 44, forms images of the first lenses 41a of the first lens array 41 near the image forming areas of the light modulation device 4R, the light modulation device 4G, and the light modulation device 4B, respectively.

[0061] The polarization conversion element 43 converts the light emitted from the second lens array 42 into one type of linearly polarized light. The polarization conversion element 43 includes, for example, a polarization separation film and a phase difference plate (not shown).

[0062] The superimposing lens 44 condenses the partial light beams emitted from the polarization conversion element 43 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.

[0063] The wavelength conversion element 20 of this embodiment includes a phosphor layer 21 that converts incident excitation light E into fluorescence Y of a wavelength band different from that of the excitation light E, a substrate 22 on which the phosphor layer 21 is provided, and a dichroic film 23 that is provided between the substrate 22 and the phosphor layer 21 and reflects the fluorescence Y. The phosphor layer 21 includes a light-transmitting resin 210, light-transmitting particles 211, and phosphor particles 212. The light-transmitting resin 210 fills the gaps between the light-transmitting particles 211 and the phosphor particles 212.

[0064] According to the wavelength conversion element 20 of this embodiment, by using the light-transmitting resin 210 as the main material of the binder, it is possible to suppress thermal deterioration of the dichroic film 23 provided below the phosphor layer 21. Therefore, it is possible to provide a wavelength conversion element 20 including a dichroic film 23 with stable optical properties in which thermal deterioration is suppressed.

[0065] Furthermore, heat generated in the phosphor particles 212 is transferred to the light-transmitting particles 211 and released to the outside of the phosphor layer 21, so that the temperature rise of the phosphor layer 21 can be suppressed compared to a configuration in which only the light-transmitting resin 210 is used as a binder. Therefore, even when an inorganic material is not used as the main material of the binder, it is possible to suppress the temperature rise of the phosphor particles 212 while suppressing the deterioration of the dichroic film 23 due to heat, thereby generating bright fluorescence Y as illumination light WL.

[0066] The manufacturing method of the wavelength conversion element 20 of this embodiment includes the steps of forming a dichroic film 23 on a substrate 22, applying a first material P1 containing a translucent resin 210 and translucent particles 211 onto the dichroic film 23, applying a second material P2 containing the translucent resin 210 and phosphor particles 212 onto the first material P1, and forming a phosphor layer 21 on the dichroic film 23 by hardening the translucent resin 210 contained in the first material P1 and the second material P2 without melting the translucent particles 211 contained in the first material P1.

[0067] According to the manufacturing method of the wavelength conversion element 20 of this embodiment, a second material P2 containing phosphor particles 212 is applied onto a first material P1 containing translucent particles 211, and then the translucent resin 210 of the first material P1 and the second material P2 is hardened, thereby manufacturing a wavelength conversion element 20 having a configuration in which the closer to the dichroic film 23 the more translucent particles 211 are mixed into the phosphor layer 21.

[0068] The light source device 2 of this embodiment includes a wavelength conversion element 20 and a light source 10 that emits excitation light E to the wavelength conversion element 20.

[0069] According to the light source device 2 of this embodiment, it is possible to provide a light source device that emits illumination light WL containing bright fluorescence Y by suppressing thermal deterioration of the dichroic film 23 and temperature rise of the phosphor particles 212.

[0070] The projector 1 of this embodiment includes a light source device 2, light modulation devices 4R, 4G, and 4B that modulate the light incident 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.

[0071] According to the projector 1 of this embodiment, by modulating the illumination light WL incident from the light source device 2, it is possible to project a bright image.

[0072] 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.

[0073] For example, in the above embodiment, a transmissive wavelength conversion element 20 is used as an example, in which illumination light WL containing fluorescence Y is emitted from the phosphor layer 21 on the side opposite to the side on which excitation light E is incident. However, the present invention can also be applied to a reflective wavelength conversion element that emits fluorescence from the same surface as the excitation light incident surface. In this case, a metal with excellent heat dissipation properties may be used as the substrate material, and a metal vapor deposition film such as aluminum or silver may be used as the reflective film. The wavelength conversion element of the present invention can also suppress warping and deterioration of the reflective film due to heat, even in a transmissive wavelength conversion element.

[0074] Furthermore, the wavelength conversion element of the above embodiment employs a fixed type in which the substrate 22 does not rotate, but the present invention is also applicable to a wavelength conversion element of a rotation type in which the substrate is rotated. In addition, the specific descriptions of the shape, number, arrangement, material, etc. of each component of the light source device and the projector are not limited to the above-described embodiments and can be changed as appropriate.

[0075] A summary of this disclosure is provided below.

[0076] (Appendix 1) a wavelength conversion layer that converts the incident first light into second light having a wavelength band different from that of the first light; a substrate on which the wavelength conversion layer is provided; a reflective film provided between the substrate and the wavelength conversion layer and configured to reflect the second light, the wavelength conversion layer includes a light-transmitting resin, light-transmitting particles, and phosphor particles; The transparent resin fills gaps between the transparent particles and the phosphor particles. Wavelength conversion element.

[0077] In the wavelength conversion element having this configuration, by using a light-transmitting resin as the main material of the binder, it is possible to suppress thermal deterioration of the reflective film provided under the wavelength conversion layer, thereby providing a wavelength conversion element having a reflective film with stable optical properties that is suppressed from being deteriorated by heat. Furthermore, since the heat generated in the phosphor particles is transferred to the light-transmitting particles and released to the outside of the wavelength conversion layer, the temperature rise of the wavelength conversion layer can be suppressed compared to a configuration in which only a light-transmitting resin is used as a binder. Therefore, even when an inorganic material is not used as the main material of the binder, bright fluorescence can be generated by suppressing the temperature rise of the phosphor particles while suppressing thermal degradation of the reflective film.

[0078] (Appendix 2) The refractive index of the light-transmitting particles relative to the light-transmitting resin is 85% or more and 115% or less. 2. A wavelength conversion element according to claim 1.

[0079] According to this configuration, the difference in refractive index between the light-transmitting resin and the light-transmitting particles is kept small, so that light scattering and reflection at the interface between the light-transmitting resin and the light-transmitting particles can be reduced.

[0080] (Appendix 3) The light-transmitting particles are made of an inorganic material. 10. The wavelength conversion element according to claim 1 or 2.

[0081] This configuration can improve the heat resistance of the light-transmitting particles.

[0082] (Appendix 4) The particle size of the light-transmitting particles is smaller than the particle size of the phosphor particles. 4. A wavelength conversion element according to any one of claims 1 to 3.

[0083] With this configuration, because the particle size of the light-transmitting particles is smaller than that of the phosphor particles, the light-transmitting particles can enter the gaps between the phosphor particles and be in contact with or in close proximity to the phosphor particles. As a result, heat generated in the phosphor particles during the generation of fluorescence is transferred to the light-transmitting particles and released, thereby efficiently suppressing the temperature rise of the phosphor particles.

[0084] (Appendix 5) the light-transmitting resin is made of a thermoplastic resin, the softening point of the light-transmitting particles is higher than the softening point of the light-transmitting resin; 5. A wavelength conversion element according to any one of claims 1 to 4.

[0085] According to this configuration, the light-transmitting particles are not deformed by heat even when the light-transmitting resin is melted at a certain temperature.

[0086] (Appendix 6) the first light is incident on the surface of the substrate opposite to the reflective film, the substrate and the reflective film transmit the first light; 6. A wavelength conversion element according to any one of claims 1 to 5.

[0087] According to this configuration, it is possible to provide a transmission type wavelength conversion element that generates bright fluorescence by suppressing the temperature rise of the phosphor particles while suppressing the deterioration of the reflective film due to heat.

[0088] (Appendix 7) the wavelength conversion layer includes a plurality of the light-transmitting particles and a plurality of the phosphor particles, the content of the light-transmitting particles varies in the thickness direction of the wavelength conversion layer, the content on the side of the reflective film is higher than the content on the side opposite to the reflective film; 7. A wavelength conversion element according to claim 6.

[0089] According to this configuration, the light-transmitting particles dissipate the heat of the phosphor particles to the substrate via the reflective film with which the wavelength conversion layer is in contact, thereby improving the heat dissipation properties of the wavelength conversion layer.

[0090] (Appendix 8) forming a reflective film on a substrate; applying a first material containing a light-transmitting resin and light-transmitting particles onto the reflective film, and applying a second material containing the light-transmitting resin and phosphor particles onto the first material; and forming a wavelength conversion layer on the reflective film by curing the light-transmitting resin contained in the first material and the second material without melting the light-transmitting particles contained in the first material. A method for manufacturing a wavelength conversion element.

[0091] According to this configuration, a second material containing phosphor particles is applied to a first material containing translucent particles, and then the translucent resins of the first material and the second material are hardened, thereby manufacturing a wavelength conversion element in which the wavelength conversion phosphor layer contains more translucent particles the closer it is to the reflective film.

[0092] (Appendix 9) When a thermosetting resin material is used as the light-transmitting resin, the curing temperature of the light-transmitting resin is lower than the softening point of the light-transmitting particles; A method for manufacturing the wavelength conversion element according to Supplementary Note 8.

[0093] According to this configuration, the light-transmitting particles are not deformed by heat even at the temperature when the light-transmitting resin is thermally cured.

[0094] (Appendix 10) A wavelength conversion element according to any one of Supplementary Note 1 to Supplementary Note 7; a light source that emits the first light to the wavelength conversion element, Light source device.

[0095] According to the light source device having this configuration, it is possible to provide a light source device that emits illumination light containing bright fluorescence by suppressing deterioration of the reflective film due to heat and temperature rise of the phosphor particles.

[0096] (Appendix 11) a light source device according to claim 10; a light modulation device that modulates light incident from the light source device; a projection optical device that projects the light modulated by the light modulation device; Equipped with projector.

[0097] According to a projector having this configuration, it is possible to provide a projector that projects bright images by modulating the illumination light incident from the light source device. [Explanation of symbols]

[0098] 1...projector, 2...light source device, 4R, 4G, 4B...light modulation device, 6...projection optical device, 20...wavelength conversion element, 21...phosphor layer (phosphor layer), 22...substrate, 23...dichroic film (reflective film), 211...light-transmitting particles, 212...phosphor particles, E...excitation light (first light), Y...fluorescence (second light), P1...first material, P2...second material.

Claims

1. a wavelength conversion layer that converts the incident first light into second light having a wavelength band different from that of the first light; a substrate on which the wavelength conversion layer is provided; a reflective film provided between the substrate and the wavelength conversion layer and configured to reflect the second light, the wavelength conversion layer includes a light-transmitting resin, light-transmitting particles, and phosphor particles; The transparent resin fills gaps between the transparent particles and the phosphor particles. Wavelength conversion element.

2. the refractive index of the light-transmitting particles relative to the refractive index of the light-transmitting resin is 85% or more and 115% or less; The wavelength conversion element according to claim 1 .

3. The light-transmitting particles are made of an inorganic material.

3. The wavelength conversion element according to claim 1.

4. The particle size of the light-transmitting particles is smaller than the particle size of the phosphor particles.

3. The wavelength conversion element according to claim 1.

5. the light-transmitting resin is made of a thermoplastic resin, the softening point of the light-transmitting particles is higher than the softening point of the light-transmitting resin; 3. The wavelength conversion element according to claim 1.

6. the first light is incident on the surface of the substrate opposite to the reflective film, the substrate and the reflective film transmit the first light; The wavelength conversion element according to claim 1 .

7. the wavelength conversion layer includes a plurality of the light-transmitting particles and a plurality of the phosphor particles, the content of the light-transmitting particles varies in the thickness direction of the wavelength conversion layer, the content on the side of the reflective film is higher than the content on the side opposite to the reflective film; The wavelength conversion element according to claim 6 .

8. forming a reflective film on a substrate; applying a first material containing a light-transmitting resin and light-transmitting particles onto the reflective film, and applying a second material containing the light-transmitting resin and phosphor particles onto the first material; and forming a wavelength conversion layer on the reflective film by hardening the light-transmitting resin contained in the first material and the second material without melting the light-transmitting particles contained in the first material. A method for manufacturing a wavelength conversion element.

9. When a thermosetting resin material is used as the light-transmitting resin, the curing temperature of the light-transmitting resin is lower than the softening point of the light-transmitting particles; The method for manufacturing a wavelength conversion element according to claim 8 .

10. The wavelength conversion element according to claim 1 ; a light source that emits the first light to the wavelength conversion element, Light source device.

11. The light source device according to claim 10; a light modulation device that modulates light incident from the light source device; a projection optical device that projects the light modulated by the light modulation device; Equipped with projector.

Images