JP2018136377A - Wavelength conversion element, light source device, and projector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a high efficient wavelength conversion element.SOLUTION: Disclosed wavelength conversion element includes: an inorganic member having a light reflecting surface including a curved surface and a light transmitting surface including a curved surface; and a wavelength conversion member which is disposed between the light reflecting surface and the light transmitting surface and emits wavelength converted light. The light reflection surface has a shape such that the first component emitted from the wavelength conversion member toward the light reflection surface from the wavelength-converted light, is reflected by the light reflection surface and enters the light transmission surface without passing through the wavelength conversion member. The light transmitting surface has a shape such that the first component and the second component emitted from the wavelength converting member toward the light transmitting surface are incident on the light transmitting surface at an angle less than the critical angle.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a wavelength conversion element, a light source device, and a projector.

  As a light source device used for a projector, a light source device that irradiates a fluorescent material with excitation light emitted from a light emitting element such as a semiconductor laser and uses fluorescent light obtained from the fluorescent material has been proposed.

  For example, Patent Document 1 below discloses a light source device that includes an excitation light irradiation device, a fluorescent light emitting device including a fluorescent wheel that emits green light upon receiving excitation light, a red light source device, and a blue light source device. Has been. In general, as the temperature of the phosphor layer increases, the luminous efficiency of the phosphor layer decreases. Therefore, in this light source device, the fluorescent wheel is cooled using a cooling fan. Patent Document 2 below discloses a wavelength conversion element made of a sintered body of an inorganic material having pores.

JP 2011-133778 A Special table 2013-518172 gazette

  When pores are provided in the phosphor layer as in the wavelength conversion element of Patent Document 2, light scattering inside the phosphor layer increases, so that the light extraction efficiency from the phosphor layer can be increased. However, since the thermal conductivity of the phosphor layer is reduced compared to the case where no pores are provided, it is difficult to cool the phosphor layer and it is difficult to increase the light emission efficiency.

  One aspect of the present invention has been made to solve the above-described problems, and an object thereof is to provide a wavelength conversion element that can obtain wavelength-converted light with high efficiency. One aspect of the present invention is to provide a light source device including the above-described wavelength conversion element. One aspect of the present invention is to provide a projector including the light source device described above.

  In order to achieve the above object, a wavelength conversion element according to one aspect of the present invention includes an inorganic member having a light reflection surface including a curved surface and a light transmission surface including a curved surface, the light reflection surface, and the light transmission surface. And a wavelength conversion member that emits wavelength-converted light, and the light reflection surface is a first of the wavelength-converted light that is emitted from the wavelength conversion member toward the light reflection surface. 1 component is reflected by the light reflecting surface, and has a shape that is incident on the light transmitting surface without passing through the wavelength converting member. The light transmitting surface includes the first component and the wavelength converting member. And the second component emitted from the light transmission surface toward the light transmission surface is incident on the light transmission surface at an angle less than a critical angle.

As a result of studying factors that reduce the efficiency of the wavelength conversion element, the present inventor has obtained the following knowledge. The “efficiency of the wavelength conversion element” in the present specification is a total of various efficiencies such as the conversion efficiency of the wavelength conversion member and the extraction efficiency of the wavelength converted light from the inorganic member to the external space.
(1) From the viewpoint of enhancing the heat exhaustability, if the amount of pores in the wavelength conversion member is decreased in an attempt to increase the thermal conductivity of the wavelength conversion member, the wavelength conversion member has insufficient scattering properties. As a result, the ratio of wavelength-converted light that cannot be emitted to the outside by being incident on the surface of the wavelength conversion member at an angle greater than the critical angle and totally reflected increases. As a result, the extraction efficiency of the wavelength converted light decreases.
(2) In order to increase the extraction efficiency of wavelength-converted light, if the inside or surface of the wavelength-converting member is sufficiently scattered, the distance that the wavelength-converted light propagates in the wavelength-converting element becomes longer. The etendue becomes larger.
(3) Part of the wavelength converted light generated inside the wavelength conversion member is reabsorbed inside the wavelength conversion member. Therefore, if the scattering of the wavelength-converted light is kept within a narrow region in an attempt to suppress the adverse effect (2), the above-described re-absorption occurs, and the conversion efficiency decreases.

  Therefore, the present inventor has conceived the wavelength conversion element according to one aspect of the present invention. According to this configuration, since the first component is reflected by the light reflecting surface and enters the light transmitting surface without passing through the wavelength converting member, reabsorption of the wavelength converted light in the wavelength converting member can be suppressed. . In addition, since the total reflection on the light transmission surface, that is, the light exit surface can be suppressed without giving the wavelength conversion member scattering, a decrease in extraction efficiency can be suppressed. In addition, since it is not necessary to include pores in the wavelength conversion element, it is easy to maintain the thermal conductivity of the wavelength conversion element high, and it is easy to cool the wavelength conversion element. Due to these factors, a highly efficient wavelength conversion element can be realized.

  In the wavelength conversion element according to one aspect of the present invention, the light reflecting surface may have a spheroid shape, and the wavelength conversion member may be provided at one focal point of the spheroid.

  According to this configuration, the position of the image of the wavelength conversion member formed by the wavelength converted light reflected by the light reflecting surface can be controlled with high accuracy.

  In the wavelength conversion element according to one aspect of the present invention, the wavelength converted light reflected by the light reflecting surface may form an image in a region adjacent to the wavelength conversion member.

  According to this configuration, since the wavelength conversion member and the region adjacent to the wavelength conversion member can be regarded as one light emitting point, the expansion of etendue can be minimized.

  In the wavelength conversion element of one aspect of the present invention, the light transmission surface may have a part of a spherical shape.

  According to this configuration, it is possible to easily realize that the wavelength conversion light emitted from the wavelength conversion member is incident on the light transmission surface at an angle less than the critical angle.

  In the wavelength conversion element according to one aspect of the present invention, the inorganic member is provided between the first inorganic member, the second inorganic member, and the first inorganic member and the second inorganic member. A third inorganic member, wherein the first inorganic member has the light reflecting surface, the second inorganic member has the light transmitting surface, and the wavelength converting member is The third inorganic member may be provided between the first inorganic member and the second inorganic member, and the third inorganic member may be provided on the optical path of the first component.

  According to this configuration, it is possible to easily process each curved surface constituting the light reflecting surface and the light transmitting surface, adjust the position of the wavelength conversion member and each inorganic member, and the like. As a result, a high-performance wavelength conversion element can be easily realized.

  In the wavelength conversion element according to one aspect of the present invention, the refractive index of the first inorganic member and the refractive index of the second inorganic member may be substantially equal to the refractive index of the wavelength conversion member.

  According to this structure, wavelength conversion light can be propagated with high efficiency from the wavelength conversion member to each inorganic member. Thereby, the wavelength conversion element can inject | emit wavelength conversion light with high efficiency.

  In the wavelength conversion element according to one aspect of the present invention, the refractive index of the first inorganic member and the refractive index of the second inorganic member may be substantially equal to the refractive index of the third inorganic member.

  According to this configuration, the wavelength-converted light can be propagated from the first inorganic member to the second inorganic member through the third inorganic member with high efficiency. Therefore, the wavelength conversion element can emit the wavelength-converted light with high efficiency.

  In the wavelength conversion element according to one aspect of the present invention, the wavelength conversion member includes a base material composed of an inorganic material, and an activator serving as a light emission center dispersed in the base material. You may be comprised from the inorganic material.

  According to this configuration, since the base material and the inorganic member of the wavelength conversion member are the same material, the wavelength conversion member and the inorganic member can be produced by a single sintering process. In addition, the light transmittance of the inorganic member can be easily controlled, and a high-performance wavelength conversion element can be manufactured at low cost.

  The wavelength conversion element according to one aspect of the present invention may further include a heat radiating member thermally connected to the light reflecting surface.

  According to this configuration, the wavelength conversion member can be efficiently cooled.

  In the wavelength conversion element according to one aspect of the present invention, the light reflecting surface may include a dielectric multilayer film.

  In one aspect of the present invention, since the light reflection surface includes a curved surface, the distribution range of the incident angle of the wavelength-converted light with respect to the light reflection surface is narrower than when the light reflection surface is planar. Therefore, if the characteristics of the dielectric multilayer film are designed for the distribution range, a light reflecting surface having a high reflectance can be formed.

  In the wavelength conversion element according to one aspect of the present invention, at least a part of the dielectric multilayer film may reflect the wavelength conversion light and transmit the excitation light for exciting the wavelength conversion member. .

  According to this configuration, since the excitation light can be incident from the light reflecting surface side, a transmission type wavelength conversion element can be realized.

  In the wavelength conversion element according to one aspect of the present invention, the light reflection surface further includes a metal reflection film provided so as to surround the dielectric multilayer film, and the dielectric multilayer film reflects the wavelength converted light. And having a property of transmitting excitation light for exciting the wavelength conversion member.

  If the dielectric multilayer film is formed on the peripheral portion of the light reflecting surface, that is, the curved surface portion having a steep inclination, the film thickness may vary and the reflection characteristics may be deteriorated. However, if a metal reflection film is formed on the peripheral portion of the light reflection surface instead of the dielectric multilayer film, the deterioration of the reflection characteristics can be reduced.

  A light source device according to one aspect of the present invention includes the wavelength conversion element according to one aspect of the present invention and a light emitting element that emits excitation light for exciting the wavelength conversion member.

  According to this configuration, it is possible to realize a light source device that generates wavelength-converted light with high efficiency.

  A projector according to one aspect of the present invention includes a light source device according to one aspect of the present invention, a light modulation device that forms image light by modulating light from the light source device according to image information, and the image light. A projection optical system.

  According to this configuration, a highly efficient projector can be realized.

It is a schematic block diagram of the projector of 1st Embodiment. It is a top view of the wavelength conversion element of a 1st embodiment. It is sectional drawing which follows the III-III line of FIG. It is a perspective view of a wavelength conversion element. It is sectional drawing of the wavelength conversion element of 2nd Embodiment. It is a schematic block diagram of the projector of 3rd Embodiment. It is sectional drawing of the wavelength conversion element of 3rd Embodiment.

Hereinafter, a first embodiment of the present invention will be described with reference to FIGS.
The projector according to the present embodiment is an example of a liquid crystal projector including a light source device including a semiconductor laser and a wavelength conversion element.
In the following drawings, in order to make each component easy to see, the scale of the size may be varied depending on the component.

  The projector according to the present embodiment is a projection type image display device that displays a color image on a screen (projected surface). The projector uses three light modulation devices corresponding to each color light of red light, green light, and blue light. The projector uses a semiconductor laser (laser diode) that can obtain light with high luminance and high output as a light emitting element of the light source device.

FIG. 1 is a schematic configuration diagram of a projector according to the present embodiment.
As shown in FIG. 1, the projector 1 includes a first light source device 100, a second light source device 102, a color separation light guide optical system 200, a light modulation device 400R, a light modulation device 400G, and a light modulation device 400B. And a synthesis optical system 500 and a projection optical system 600.
The 1st light source device 100 of this embodiment respond | corresponds to the light source device of a claim.

  The first light source device 100 includes a first light emitting element 10, a collimating optical system 70, a dichroic mirror 80, a collimating condensing optical system 90, a wavelength converting element 20, a homogenizer optical system 125, and a polarization converting element 140. And a superimposing lens 150. The wavelength conversion element 20 will be described in detail later.

The first light emitting element 10 is composed of a semiconductor laser that emits blue excitation light E. The peak wavelength of the emission intensity of the excitation light E is, for example, 445 nm. The 1st light emitting element 10 may be comprised from one semiconductor laser, and may be comprised from the several semiconductor laser. The first light emitting element 10 may be a semiconductor laser that emits blue light having a wavelength other than 445 nm (for example, 460 nm). The first light emitting element 10 is arranged so that the optical axis of the first light emitting element 10 is orthogonal to the illumination optical axis 100ax.
The 1st light emitting element 10 of this embodiment respond | corresponds to the light emitting element of a claim.

  The collimating optical system 70 includes a first lens 72 and a second lens 74. The collimating optical system 70 substantially collimates the light emitted from the first light emitting element 10. The 1st lens 72 and the 2nd lens 74 are comprised from the convex lens.

  The dichroic mirror 80 is provided in the optical path from the collimating optical system 70 to the collimating condensing optical system 90. The dichroic mirror 80 is disposed so as to intersect with each of the optical axis 110ax and the illumination optical axis 100ax of the first light emitting element 10 at an angle of 45 °. The dichroic mirror 80 reflects light in the blue wavelength range and transmits light in the yellow wavelength range including red light and green light.

  The collimating condensing optical system 90 cooperates with a light transmitting surface 21t of the wavelength conversion element 20 described later, and the wavelength conversion member of the wavelength conversion element 20 in a state where the excitation light E emitted from the dichroic mirror 80 is substantially condensed. And a function of making the fluorescent light Y emitted from the wavelength conversion member 22 substantially parallel. The collimator condensing optical system 90 includes a first lens 92 and a second lens 94. The 1st lens 92 and the 2nd lens 94 are comprised from the convex lens.

  The second light source device 102 includes a second light emitting element 710, a condensing optical system 760, a diffusion plate 732, and a collimating optical system 770.

  The second light emitting element 710 is composed of a semiconductor laser that emits blue light B. The peak wavelength of the emission intensity of the blue light B is different from the peak wavelength of the emission intensity of the excitation light E from the first light emitting element 10 and is, for example, 460 nm. However, a semiconductor laser that emits light having the same peak wavelength as the peak wavelength of the emission intensity of the excitation light E from the first light emitting element 10 may be used as the second light emitting element 710.

  The condensing optical system 760 includes a first lens 762 and a second lens 764. The condensing optical system 760 condenses the blue light B emitted from the second light emitting element 710 in the vicinity of the diffusion plate 732. The 1st lens 762 and the 2nd lens 764 are comprised from the convex lens.

  The diffusing plate 732 diffuses the blue light B emitted from the second light emitting element 710 to obtain blue light B having a light distribution similar to the light distribution of the fluorescent light Y emitted from the wavelength conversion element 20. As the diffusion plate 732, for example, polished glass made of optical glass can be used.

  The collimating optical system 770 includes a first lens 772 and a second lens 774. The collimating optical system 770 substantially parallelizes the light emitted from the diffusion plate 732. The 1st lens 772 and the 2nd lens 774 are comprised from the convex lens.

  The blue light B emitted from the second light source device 102 is reflected by the dichroic mirror 80 and then combined with the fluorescent light Y transmitted through the dichroic mirror 80 to become white illumination light W. The illumination light W is incident on the homogenizer optical system 125.

  The homogenizer optical system 125 includes a first lens array 120 and a second lens array 130. The first lens array 120 includes a plurality of first small lenses 122 for dividing the light emitted from the dichroic mirror 80 into a plurality of partial light beams. The plurality of first small lenses 122 are arranged in a matrix in a plane orthogonal to the illumination optical axis 100ax.

  The second lens array 130 includes a plurality of second small lenses 132 corresponding to the plurality of first small lenses 122 of the first lens array 120. The second lens array 130, together with the superimposing lens 150, displays the images of the first small lenses 122 of the first lens array 120 in the vicinity of the image forming regions of the light modulation device 400R, the light modulation device 400G, and the light modulation device 400B. To form an image. The plurality of second small lenses 132 are arranged in a matrix in a plane orthogonal to the illumination optical axis 100ax.

  The polarization conversion element 140 converts each partial light beam divided by the first lens array 120 into linearly polarized light. The polarization conversion element 140 includes a polarization separation layer, a reflection layer, and a retardation layer. The polarization separation layer transmits one linearly polarized light component of the polarized light components included in the light from the wavelength conversion element as it is and reflects the other linearly polarized light component in a direction perpendicular to the illumination optical axis 100ax. The reflective layer reflects the other linearly polarized light component reflected by the polarization separation layer in a direction parallel to the illumination optical axis 100ax. The retardation layer converts the other linearly polarized light component reflected by the reflective layer into one linearly polarized light component.

  The superimposing lens 150 collects the partial light beams from the polarization conversion element 140 and superimposes them on each other in the vicinity of the image forming regions of the light modulation device 400R, the light modulation device 400G, and the light modulation device 400B. The first lens array 120, the second lens array 130, and the superimposing lens 150 constitute an integrator optical system that uniformizes the in-plane light intensity distribution of the light emitted from the wavelength conversion element 20.

  The color separation light guide optical system 200 separates the white illumination light W into red light R, green light G, and blue light B. The color separation light guide optical system 200 includes a first dichroic mirror 210, a second dichroic mirror 220, a first total reflection mirror 230, a second total reflection mirror 240, a third total reflection mirror 250, and a first relay. A lens 260 and a second relay lens 270 are provided.

  The first dichroic mirror 210 has a function of separating the illumination light W emitted from the first light source device 100 into red light R and other light (green light G and blue light B). The first dichroic mirror 210 transmits red light R and reflects other light (green light G and blue light B). On the other hand, the second dichroic mirror 220 has a function of separating other light into green light G and blue light B. The second dichroic mirror 220 reflects green light G and transmits blue light B.

  The first total reflection mirror 230 is disposed in the optical path of the red light R, and reflects the red light R transmitted through the first dichroic mirror 210 toward the light modulation device 400R. The second total reflection mirror 240 and the third total reflection mirror 250 are disposed in the optical path of the blue light B, and reflect the blue light B transmitted through the second dichroic mirror 220 toward the light modulation device 400B. The green light G is reflected by the second dichroic mirror 220 toward the light modulation device 400G.

  The first relay lens 260 and the second relay lens 270 are disposed on the light emission side of the second dichroic mirror 220 in the optical path of the blue light B. The first relay lens 260 and the second relay lens 270 have a function of compensating for the loss of the blue light B caused by the optical path length of the blue light B being longer than the optical path lengths of the red light R and the green light G. Yes.

  The light modulation device 400R modulates the red light R according to the image information, and forms image light corresponding to the red light R. The light modulation device 400G modulates the green light G according to the image information and forms image light corresponding to the green light G. The light modulation device 400B modulates the blue light B according to the image information and forms image light corresponding to the blue light B.

  For example, a transmissive liquid crystal panel is used for the light modulation device 400R, the light modulation device 400G, and the light modulation device 400B. In addition, a pair of polarizing plates (not shown) are arranged on the incident side and the emission side of the liquid crystal panel so that only linearly polarized light in a specific direction is transmitted.

  A field lens 300R, a field lens 300G, and a field lens 300B are disposed on the incident side of the light modulation device 400R, the light modulation device 400G, and the light modulation device 400B, respectively. Field lens 300R, field lens 300G, and field lens 300B collimate red light R, green light G, and blue light B incident on light modulation device 400R, light modulation device 400G, and light modulation device 400B, respectively.

  The combining optical system 500 combines the image light corresponding to the red light R, the green light G, and the blue light B when the image light from the light modulation device 400R, the light modulation device 400G, and the light modulation device 400B enters. Then, the combined image light is emitted toward the projection optical system 600. For the combining optical system 500, for example, a cross dichroic prism is used.

  The projection optical system 600 includes a projection lens group 6. The projection optical system 600 enlarges and projects the image light combined by the combining optical system 500 toward the screen SCR. Thereby, an enlarged color video (image) is displayed on the screen SCR.

Hereinafter, the configuration of the wavelength conversion element 20 will be described.
FIG. 2 is a plan view of the wavelength conversion element 20 viewed from the direction of the illumination optical axis 100ax. FIG. 3 is a cross-sectional view of the wavelength conversion element 20 taken along line III-III in FIG. FIG. 4 is a perspective view of the wavelength conversion element 20.

  As shown in FIGS. 2 and 3, the wavelength conversion element 20 includes an inorganic member 21, a wavelength conversion member 22, and a heat dissipation member 23. The wavelength conversion member 22 is embedded in the inorganic member 21. Hereinafter, the inorganic member 21 in which the wavelength conversion member 22 is embedded is referred to as a wavelength conversion unit 24.

The inorganic member 21 has a light reflecting surface 21r made of a curved surface and a light transmitting surface 21t made of a curved surface. Of the surface of the inorganic member 21 in FIG. 3, the substantially lower half is the light reflecting surface 21r, and the substantially upper half is the light transmitting surface 21t. The inorganic member 21 has light transmittance and is made of an inorganic material that forms a base material of a wavelength conversion member 22 described later. Specifically, the inorganic member 21 is made of YAG ceramics made of (Y, Gd) ₃ (Al, Ga) ₅ O ₁₂ (YAG). Thus, although the inorganic member 21 is one member which consists of a uniform inorganic material as a whole, the part which has the light reflection surface 21r among the inorganic members 21 is made into the 1st inorganic member 211 for convenience of explanation. The portion having the light transmission surface 21t is referred to as a second inorganic member 212.

  As shown in FIG. 4, the light reflecting surface 21r has a spheroid shape. That is, the first inorganic member 211 includes a spheroid major axis J1 (see FIG. 2) and has a shape obtained by cutting the spheroid in half on a plane parallel to the upper surface of the wavelength conversion member 22. . In general, there are two types of spheroids: an ellipsoid having an elliptical major axis as a rotational axis (oblong ellipsoid) and an ellipsoid having an elliptical minor axis as a rotational axis (flat ellipsoid). In the present embodiment, the light reflecting surface 21r has an oblong ellipsoidal shape with the elliptical long axis as the rotation axis.

  Therefore, as shown in FIG. 3, the surface other than the light reflecting surface 21r of the first inorganic member 211 is a flat surface 211s in contact with the second inorganic member 212, as viewed from the surface normal direction of the flat surface 211s. The shape of the first inorganic member 211 is an ellipse as shown by a broken line C in FIG. Hereinafter, the flat surface 211s is referred to as a first flat surface. The light reflecting surface 21r reflects the fluorescent light Y emitted from the wavelength conversion member 22.

  A reflective film 26 made of a dielectric multilayer film is formed on the light reflecting surface 21 r of the first inorganic member 211. The dielectric multilayer film is designed to reflect light having a wavelength in the visible range when light is incident at an incident angle near 0 degrees.

  As shown in FIG. 4, the light transmission surface 21t has a shape of a part of a spherical surface. That is, the second inorganic member 212 includes a sphere diameter and has a shape obtained by cutting the sphere in half along a plane parallel to the upper surface of the wavelength conversion member 22. Therefore, the surface of the second inorganic member 212 other than the light transmission surface 21t is a flat surface 212s that contacts the first inorganic member 211. The shape of the flat surface 212s viewed from the surface normal direction is a solid line in FIG. It is a circle as indicated by D. Hereinafter, the flat surface 212s is referred to as a second flat surface. The light transmission surface 21t transmits the fluorescent light Y emitted from the wavelength conversion member 22, and transmits the excitation light E incident from the outside.

  As shown in FIG. 3, an antireflection film 28 is formed on the light transmission surface 21 t of the second inorganic member 212. As the antireflection film 28, a known antireflection coating material made of, for example, magnesium fluoride (MgF2) can be used.

  As shown in FIG. 2, an ellipse C, which is the shape of the first flat surface 211s, is included within a circle D, which is the shape of the second flat surface 212s. That is, the length of the major axis J1 of the ellipse C is equal to the diameter of the circle D. Therefore, the peripheral edge portion of the second flat surface 212s protrudes outside the first flat surface 211s in the direction of the minor axis J2 of the ellipse C.

The wavelength conversion member 22 is composed of a phosphor layer that is excited by the excitation light E emitted from the first light emitting element 10 and emits yellow fluorescent light Y. The wavelength conversion member 22 includes a base material made of an inorganic material and an activator that becomes a light emission center dispersed in the base material. In the case of this embodiment, the wavelength conversion member 22 is composed of a YAG-based phosphor made of (Y, Gd) ₃ (Al, Ga) ₅ O ₁₂ (YAG: Ce) in which Ce is dispersed as an activator. . The shape of the wavelength conversion member 22 viewed from the surface normal direction of the wavelength conversion member 22, that is, the direction of the illumination optical axis 100 ax is rectangular as shown in FIG. 2 in the present embodiment, but is necessarily necessarily rectangular. For example, it may be circular.

  The phosphor layer constituting the wavelength conversion member 22 does not necessarily need to be composed of a YAG phosphor, but it is desirable to use a garnet phosphor. Garnet phosphors have higher thermal conductivity than other phosphors, and are highly reliable in a high heat environment. Therefore, high-output fluorescent light can be obtained even when used in a light source device using a fixed phosphor instead of a rotating wheel type.

  As shown in FIG. 2, the spheroid having the shape of the light reflecting surface 21r is an ellipsoid having the major axis J1 of the ellipse C as the rotation axis, and thus has two focal points. The wavelength conversion member 22 is provided so that the center of the wavelength conversion member 22 is located at one focal point F1 of the spheroid.

  In FIG. 3, the wavelength conversion member 22 is embedded in the first inorganic member 211 so that the upper surface of the wavelength conversion member 22 is flush with the interface between the first flat surface 211s and the second flat surface 212s. ing. However, instead of this configuration, the wavelength conversion member 22 includes a second inorganic member such that the lower surface of the wavelength conversion member 22 is flush with the interface between the first flat surface 211s and the second flat surface 212s. 212 may be embedded.

  As will be described in detail later, the fluorescent light Y emitted from the wavelength conversion member 22 and reflected by the light reflection surface 21r passes through a specific region on the same plane as the light emission surface of the wavelength conversion member 22, and has a wavelength in this region. The image of the conversion member 22 is tied. Hereinafter, a region where the fluorescent light Y reflected by the light reflecting surface 21r passes and connects the images of the wavelength conversion member 22 is referred to as a passing region 32. As shown in FIG. 2, the pass region 32 is adjacent to the wavelength conversion member 22, and the center of the pass region 32 is located at the other focal point F2 of the spheroid. That is, the wavelength conversion member 22 and the passage region 32 are arranged so as to form one continuous region 33.

  In the case of this embodiment, since the distance between the focal points F1 and F2 is so short that the wavelength conversion member 22 and the passage region 32 are adjacent to each other, the oblateness of the spheroid is small and the shape is close to a sphere. Therefore, as shown in FIG. 2, the area of the portion of the peripheral portion of the second flat surface 212s that protrudes outside the first flat surface 211s is small.

  As shown in FIG. 2, the center of the spherical surface forming the light transmission surface 21 t coincides with the center C <b> 1 of the region 33. That is, the center of the circle D forming the shape of the second flat surface 212 s coincides with the center C <b> 1 of the region 33.

  In the wavelength conversion element 20 of the present embodiment, both the wavelength conversion member 22 and the inorganic member 21 are obtained by eliminating scatterers such as pores that cause light scattering. As a result, the fluorescent light Y generated inside the wavelength conversion member 22 enters the inorganic member 21 from the wavelength conversion member 22 through the shortest optical path. Furthermore, since the fluorescent light Y is not unnecessarily scattered inside the inorganic member 21, it does not reenter the wavelength conversion member 22.

  The heat dissipating member 23 is composed of a plate made of a metal such as copper (Cu) having a relatively high thermal conductivity. As shown in FIG. 3, a recess 23 h having a shape corresponding to the ellipsoidal shape of the light reflection surface 21 r of the wavelength conversion unit 24 is provided on one surface of the heat dissipation member 23. As for the wavelength conversion part 24, the 1st inorganic member 211 side is accommodated in the recessed part 23h. The light reflecting surface 21r of the wavelength converter 24 and the heat radiating member 23 are joined together by an adhesive or solder (not shown) having high thermal conductivity. Thereby, the heat generated in the wavelength conversion section 24 is efficiently transmitted to the heat radiating member 23 and can be exhausted.

Hereinafter, the operation of the wavelength conversion element 20 of the present embodiment will be described with reference to FIG.
Of the fluorescent light Y emitted from the wavelength conversion member 22 (wavelength conversion light), the light from the wavelength conversion member 22 toward the light reflection surface 21r (downward) is defined as the first component Y1, and the light transmission surface from the wavelength conversion member 22 The light traveling toward 21t (upward) is defined as a second component Y2.

  As shown in FIG. 3, the excitation light E enters the second inorganic member 212 through the light transmission surface 21 t and is condensed on the wavelength conversion member 22. Thereby, the wavelength conversion member 22 emits the fluorescent light Y.

  The first component Y1 emitted from the wavelength conversion member 22 travels toward the light reflection surface 21r, is reflected by the light reflection surface 21r, and returns to the wavelength conversion member 22 side. At this time, since the wavelength conversion member 22 is provided at the focal point F1, the first component Y1 reflected by the light reflecting surface 21r passes through the focal point F2, that is, forms an image of the wavelength conversion member 22 in the passage region 32. Thereafter, the process proceeds toward the light transmission surface 21t.

  In other words, the light reflection surface 21r has a shape in which the first component Y1 is reflected by the light reflection surface 21r and enters the light transmission surface 21t without passing through the wavelength conversion member 22. If the first component Y1 follows the optical path as described above, the shape of the light reflecting surface 21r may not be a spheroid.

  Since the light transmission surface 21t has a shape of a part of a spherical surface and the passage region 32 is located at the approximate center of the sphere, the first component Y1 traveling from the light reflection surface 21r toward the light transmission surface 21t is The light is incident on the light transmission surface 21t at an angle less than the critical angle, and is transmitted through the light transmission surface 21t.

  Since the wavelength conversion member 22 is located at the approximate center of the sphere, the second component Y2 that has advanced from the wavelength conversion member 22 toward the light transmission surface 21t is also less than the critical angle with respect to the light transmission surface 21t. Incident light is transmitted through the light transmitting surface 21t.

  The light transmission surface 21t has a shape in which the first component Y1 and the second component Y2 reflected by the light reflection surface 21r are incident on the light transmission surface 21t at an angle less than the critical angle. As described above, if the first component Y1 and the second component Y2 can be incident on the light transmission surface 21t at an angle less than the critical angle, the shape of the light transmission surface 21t may not be a sphere.

  In the wavelength conversion element 20 of this embodiment, since the first component Y1 emitted from the wavelength conversion member 22 does not re-enter the wavelength conversion member 22, it is difficult for the wavelength conversion member 22 to reabsorb, and the conversion efficiency is reduced. Reduced. In addition, since the total reflection at the light transmission surface 21t can be suppressed without giving the wavelength conversion member 22 and the inorganic member 21 scattering, a decrease in extraction efficiency can be reduced. In addition, since it is not necessary to contain pores in the wavelength conversion element 20, the thermal conductivity of the wavelength conversion element 20 does not decrease due to the presence of the pores, and the wavelength conversion element 20 is easily cooled. Due to these factors, a highly efficient wavelength conversion element 20 can be realized.

  In the wavelength conversion element 20 of the present embodiment, even if the oblateness of the spheroid forming the shape of the light reflecting surface 21r is further increased and the distance between the two focal points F1 and F2 of the spheroid is increased, A configuration in which the first component Y1 reflected by the light reflecting surface 21r is not reincident on the wavelength conversion member 22 can be realized. However, in that case, a substantial light emitting area as the wavelength conversion element 20 is expanded, and etendue is increased. Therefore, it is preferable to set the flatness ratio so small that the wavelength conversion member 22 and the passage region 32 are in contact with each other.

  In the wavelength conversion element 20 of the present embodiment, the oblateness of the spheroid forming the light reflecting surface 21r is reduced so that the positions of the two focal points F1 and F2 are sufficiently close to each other, and the wavelength conversion member 22 is moved to one side. A configuration arranged at the focal point F1 is employed. Thereby, the position of the passage area 32 can be controlled with high accuracy. Thereby, since the passage region 32 is formed in the region adjacent to the wavelength conversion member 22, the wavelength conversion member 22 and the passage region 32 can be regarded as one light emission point. As a result, the expansion of the etendue can be minimized as long as the first component Y1 does not re-enter the wavelength conversion member 22.

  Moreover, in the wavelength conversion element 20 of this embodiment, since the light transmission surface 21t has a spherical shape, the fluorescent light Y emitted from the wavelength conversion member 22 is incident on the light transmission surface 21t at an angle less than the critical angle. The incident can be easily realized.

  In the wavelength conversion element 20 of the present embodiment, the first inorganic member 211 and the second inorganic member 212 are made of the same inorganic material, and are made of an inorganic material that forms the base material of the wavelength conversion member 22. Has been. Therefore, the refractive index of the first inorganic member 211 and the refractive index of the second inorganic member 212 are equal to each other, and are approximately equal to the refractive index of the wavelength conversion member 22. Thereby, Fresnel reflection between the wavelength conversion member 22 and each inorganic member 211,212 can be substantially eliminated, and the fluorescent light Y can be propagated from the wavelength conversion member 22 to each inorganic member 211,212 with high efficiency. it can. As a result, the wavelength conversion element 20 can emit the fluorescent light Y with high efficiency.

  Further, when the wavelength conversion element 20 is manufactured, after the wavelength conversion member 22 and the inorganic member 21 are formed as one precursor, the wavelength conversion member 22 and the inorganic member 21 are produced by the same sintering process. be able to. According to this method, the light transmittance of the inorganic member 21 can be controlled relatively easily, and an effect that the high-performance wavelength conversion element 20 can be manufactured at a relatively low cost can be obtained.

  In addition, since the wavelength conversion element 20 of the present embodiment includes the heat dissipation member 23 thermally connected to the light reflecting surface 21r, the wavelength conversion element 20 having a curved surface is stabilized by the heat dissipation member 23. The wavelength conversion unit 24 can be efficiently cooled.

  In the wavelength conversion element 20 of the present embodiment, the light reflecting surface 21r includes a dielectric multilayer film, and the incident angle of the fluorescent light Y with respect to the dielectric multilayer film falls within a narrow angle range depending on the shape of the light reflecting surface 21r. be able to. Therefore, if the characteristics of the dielectric multilayer film are designed with respect to the angular range, the light reflecting surface 21r having a sufficiently high reflectance can be formed.

  Instead of the configuration of the present embodiment, the reflective film 26 may be formed of a metal such as aluminum or silver. In the dielectric multilayer film, it is necessary to control the thickness of each layer on the order of nm, and it may be difficult to perform film formation in which the thickness is precisely controlled on the curved surface of the inorganic member. On the other hand, since the metal film can be easily formed as compared with the dielectric multilayer film, the reflective film 26 having a relatively high reflectance can be formed at low cost. As a result, it is possible to achieve both efficiency improvement and cost reduction.

  Since the first light source device 100 of the present embodiment includes the wavelength conversion element 20 described above, the etendue can be reduced with high efficiency.

  Since the projector 1 of the present embodiment includes the first light source device 100 described above, high efficiency can be realized.

[Second Embodiment]
Hereinafter, a second embodiment of the present invention will be described with reference to FIG.
The basic configuration of the projector and the light source device of the second embodiment is the same as that of the first embodiment, and the configuration of the wavelength conversion element is different from that of the diffusion device of the first embodiment. Therefore, descriptions of the projector and the light source device are omitted, and only the wavelength conversion element is described.
FIG. 5 is a cross-sectional view of the wavelength conversion element of the second embodiment.
In FIG. 5, the same reference numerals are given to the same components as those used in the first embodiment, and the description thereof is omitted.

  As shown in FIG. 5, the wavelength conversion element 40 of the present embodiment includes a first inorganic member 211, a second inorganic member 212, a wavelength conversion member 22, a third inorganic member 213, and a heat dissipation member 23. And. The first inorganic member 211 and the second inorganic member 212 are configured separately.

  The wavelength conversion member 22 is provided so as to be sandwiched between the first flat surface 211 s of the first inorganic member 211 and the second flat surface 212 s of the second inorganic member 212. The wavelength conversion member 22 is provided at one focal point F1 of the spheroid that forms the light reflecting surface 21r.

  The third inorganic member 213 is provided between the first inorganic member 211 and the second inorganic member 212. The third inorganic member 213 is provided such that the center of the third inorganic member 213 coincides with the other focal point F2 of the spheroid that forms the light reflecting surface 21r. The wavelength conversion member 22 and the third inorganic member 213 are provided in regions adjacent to each other between the first inorganic member 211 and the second inorganic member 212.

The third inorganic member 213, the first inorganic member 211, and the second inorganic member 212 are all made of the same inorganic material, for example, (Y, Gd) ₃ (Al, Ga) ₅ O ₁₂ (YAG). It is composed of YAG ceramics. Therefore, the refractive index of the first inorganic member 211, the refractive index of the second inorganic member 212, and the refractive index of the third inorganic member 213 are substantially equal to each other.

  The third inorganic member 213 is provided on the optical path of the first component Y1, and the first component Y1 traveling from the light reflecting surface 21r toward the light transmitting surface 21t is transferred from the first inorganic member 211 to the second. It has a role of efficiently transmitting to the inorganic member 212. In order to fulfill the above role, the refractive index of the third inorganic member 213 is desirably substantially equal to the refractive index of the first inorganic member 211 and the refractive index of the second inorganic member 212.

  Adhesion having high thermal conductivity in a region between the first inorganic member 211 and the second inorganic member 212 other than the region where the wavelength conversion member 22 and the third inorganic member 213 are provided. A bonding layer 42 made of an agent or solder is provided. That is, the first inorganic member 211 and the second inorganic member 212 are bonded via the bonding layer 42. The bonding layer 42 may have light transmission properties, but the first component Y1 reflected by the light reflection surface 21r does not pass through a path other than the third inorganic member 213, and thus has light transmission properties. It does not have to be.

The interface between the first inorganic member 211 and the wavelength conversion member 22 and the interface between the first inorganic member 211 and the third inorganic member 213 are polished smoothly so that the surfaces in contact with each other can be in close contact with each other. Similarly, the interface between the second inorganic member 212 and the wavelength conversion member 22 and the interface between the second inorganic member 212 and the third inorganic member 213 are polished smoothly so that the surfaces in contact with each other can be in close contact with each other. Yes.
Other configurations are the same as those of the first embodiment.

  Also in this embodiment, the same effect as the first embodiment that the wavelength conversion element 40 with high efficiency and small etendue can be realized is obtained.

  Moreover, in this embodiment, each of the 1st inorganic member 211, the 2nd inorganic member 212, the wavelength conversion member 22, the 3rd inorganic member 213, etc. can be manufactured as a separate component. Therefore, it becomes easy to perform operations such as processing of the light reflection surface 21r and the light transmission surface 21t and position adjustment of the wavelength conversion member 22 and the inorganic members 211, 212, and 213. As a result, a high-performance wavelength conversion element 40 can be easily realized.

  In the present embodiment, the third inorganic member 213 is separate from the first inorganic member 211 and the second inorganic member 212, but either of the first inorganic member 211 and the second inorganic member 212 is used. It may be integral with either one.

[Third Embodiment]
Hereinafter, a third embodiment of the present invention will be described with reference to FIGS. 6 and 7.
While the wavelength conversion element of the first and second embodiments is a reflection type wavelength conversion element, the wavelength conversion element of the third embodiment is a transmission type wavelength conversion element.
FIG. 6 is a schematic configuration diagram of the projector according to the third embodiment. FIG. 7 is a cross-sectional view of the wavelength conversion element of the third embodiment.
In FIG. 6 and FIG. 7, the same code | symbol is attached | subjected to the same component as drawing used in 1st Embodiment, and description is abbreviate | omitted.

As shown in FIG. 6, the projector 51 includes a first light source device 104, a second light source device 102, a color separation light guide optical system 200, a light modulation device 400R, a light modulation device 400G, and a light modulation device 400B. And a synthesis optical system 500 and a projection optical system 600.
The 1st light source device 104 of this embodiment respond | corresponds to the light source device of a claim.

  The first light source device 104 includes a first light emitting element 10, a collimating optical system 70, a dichroic mirror 80, a collimating condensing optical system 90, a wavelength conversion element 60, a homogenizer optical system 125, and a polarization conversion element 140. And a superimposing lens 150. The wavelength conversion element 60 will be described in detail later.

  The first light emitting element 10 is composed of a semiconductor laser that emits blue excitation light E. The condensing optical system 70 includes a first lens 72 and a second lens 74 and condenses the light emitted from the first light emitting element 10 toward the wavelength conversion member 22. In the first light source device 104 of the present embodiment, the first light emitting element 10 and the condensing optical system 70 are arranged such that their optical axes coincide with the illumination optical axis 100ax. With this arrangement, contrary to the first embodiment, the excitation light E enters the wavelength conversion element 60 from the light reflecting surface side.

  As shown in FIG. 7, the wavelength conversion element 60 includes a first inorganic member 211, a second inorganic member 212, a wavelength conversion member 22, and a heat dissipation member 62. The first inorganic member 211 has a light reflecting surface 21r. In the first embodiment, the dielectric multilayer film is provided over the entire area of the light reflecting surface 21r. In contrast, in the present embodiment, a wavelength selective reflection film 64 made of a dielectric multilayer film is provided in a partial region of the light reflection surface 21r, and a metal reflection such as aluminum or silver is provided in the remaining region of the light reflection surface 21r. A visible light reflection film 66 made of a film is provided.

  The dielectric multilayer film constituting the wavelength selective reflection film 64 has a characteristic of transmitting the excitation light E for exciting the wavelength conversion member 22 and reflecting the fluorescent light Y. On the other hand, the visible light reflecting film 66 has a characteristic of reflecting light over the entire visible light wavelength region. The metal reflection film constituting the visible light reflection film 66 is provided so as to surround the dielectric multilayer film constituting the wavelength selective reflection film 64.

  Since the wavelength conversion element 60 of the present embodiment is a transmissive wavelength conversion element, the heat radiating member 62 is provided with an opening 62h for allowing the excitation light E to enter. The wavelength conversion unit 68 including the first inorganic member 211, the second inorganic member 212, and the wavelength conversion member 22 is fitted into the opening 62h of the heat radiating member 62, and has a high thermal conductivity adhesive or solder (not shown). Thus, the heat dissipation member 62 is joined. Thereby, the heat generated in the wavelength conversion unit 68 is efficiently transmitted to the heat radiating member 62 and can be exhausted.

Of the light reflection surface 21r, the region where the wavelength selective reflection film 64 is provided is exposed to the outside through the opening 62h of the heat dissipation member 62, and the region where the visible light reflection film 66 is provided is in contact with the heat dissipation member 62.
Other configurations are the same as those of the first embodiment.

  In the wavelength conversion element 60 of the present embodiment, the excitation light E passes through the wavelength selective reflection film 64 on the light reflection surface 21 r side and enters the wavelength conversion member 22. The behavior of the fluorescent light Y emitted from the wavelength conversion member 22 is the same as in the first embodiment.

  Also in this embodiment, the same effects as those in the first and second embodiments can be obtained, such that the wavelength conversion element 60 with high efficiency and low etendue can be realized.

  If a dielectric multilayer film is formed on the peripheral portion of the light reflecting surface 21r, that is, a curved surface portion having a steep slope, there is a possibility that the film thickness varies and the reflection characteristics are deteriorated. However, in this embodiment, since the metal reflection film is provided on the peripheral portion of the light reflection surface 21r instead of the dielectric multilayer film, the visible light reflection film 66 can be easily formed, and the reflection characteristics are deteriorated. Can be reduced. As a result, the wavelength conversion element 60 can be provided at a lower cost compared to the case where all of the light reflecting surface 21r is formed of a dielectric multilayer film.

  In the present embodiment, since a transmissive wavelength conversion element can be realized, the wavelength conversion element 60 can be applied to the first light source device 104 having an optical configuration as shown in FIG.

  As the visible light reflection film 66, a dielectric multilayer film of a type different from the dielectric multilayer film constituting the wavelength selective reflection film 64 may be used instead of the metal reflection film. In this case, since the reflectance can be made higher than when a metal reflective film is used, a highly efficient wavelength conversion element can be realized.

  Alternatively, instead of the configuration of the present embodiment, one type of dielectric multilayer film that constitutes the wavelength selective reflection film 64 may be formed over the entire light reflection surface 21r. That is, in the element configuration of this embodiment, the visible light reflection film 66 is formed in a region where the heat radiating member 62 is covered, and the excitation light E is not originally incident. A reflective film 64 may be formed. When this configuration is employed, it is not necessary to perform film formation by changing the type of film according to the region of the light reflecting surface 21r, and the wavelength conversion element can be provided at low cost.

The technical scope of the present invention is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the present invention.
For example, in the above embodiment, YAG ceramics is used for the inorganic member, but alumina having a high thermal conductivity and a refractive index close to that of YAG may be used. Since alumina has optical anisotropy, it has higher light scattering properties than YAG, but its thermal conductivity is higher than YAG (alumina: about 30 W / m · K, YAG: about 10 W / m · K). . Therefore, even if the etendue of the light source becomes somewhat large, it is suitable for a light source device for applications that require high heat exhaustion.

  Alternatively, as the inorganic member, glass having a refractive index close to that of YAG may be used. Glass can be easily machined and cut as compared with ceramic materials that are hard and difficult to machine. Therefore, it is suitable for a light source device that is required to be inexpensive even if the exhaust heat performance is somewhat sacrificed.

  Moreover, in the said embodiment, although the reflective film was formed in the light reflection surface of an inorganic member, it replaced with this structure and the reflection film does not necessarily need to be formed in the light reflection surface. Alternatively, a metal having a high reflectance may be used as the material of the heat dissipation member, and a heat dissipation member in contact with the light reflecting surface of the inorganic member may be used as the reflector. Moreover, the antireflection film does not necessarily have to be formed on the light transmission surface.

  In the above embodiment, the entire light reflection surface has a spheroid shape and the entire light transmission surface has a sphere shape. However, a part of the light reflection surface has a spheroid shape. It may have a shape, and a part of the light transmission surface may have a spherical shape. For example, only the central part near the wavelength conversion member of the light reflecting surface may have a spheroid shape, and the peripheral part may have a shape other than the spheroid. The same applies to the light transmission surface. Of the light transmission surface, only the central portion near the wavelength conversion member may have a spherical shape, and the peripheral portion may have a shape other than the spherical shape.

  In addition, the number, shape, material, arrangement, and the like of each component constituting the wavelength conversion element and the light source device can be appropriately changed. In the above embodiment, a projector including three light modulation devices has been exemplified. However, the present invention can also be applied to a projector that displays a color image with one light modulation device. Furthermore, the light modulation device is not limited to the above-described liquid crystal panel, and for example, a digital mirror device can be used.

In addition, the shape, number, arrangement, material, and the like of various components of the projector are not limited to the above-described embodiment, and can be changed as appropriate.
Moreover, although the example which mounted the light source device by this invention in the projector was shown in the said embodiment, it is not restricted to this. The light source device according to the present invention can also be applied to lighting fixtures, automobile headlights, and the like.

  DESCRIPTION OF SYMBOLS 1,51 ... Projector, 10 ... 1st light emitting element (light emitting element), 20, 40, 60 ... Wavelength conversion element, 21 ... Inorganic member, 21r ... Light reflection surface, 21t ... Light transmission surface, 22 ... Wavelength conversion member, 23, 62 ... Radiating member, 100, 104 ... First light source device (light source device), 211 ... First inorganic member, 212 ... Second inorganic member, 213 ... Third inorganic member, 400R, 400G, 440B ... Light modulation device, 600... Projection optical system.

Claims (14)

An inorganic member having a light reflecting surface including a curved surface and a light transmitting surface including a curved surface;
A wavelength converting member that is provided between the light reflecting surface and the light transmitting surface and emits wavelength converted light; and
The light reflection surface reflects the first component emitted from the wavelength conversion member toward the light reflection surface, out of the wavelength converted light, without passing through the wavelength conversion member. Having a shape incident on the light transmission surface;
The light transmission surface has a shape in which the first component and the second component emitted from the wavelength conversion member toward the light transmission surface are incident on the light transmission surface at an angle less than a critical angle. A wavelength conversion element. The light reflecting surface has a spheroid shape,
The wavelength conversion element according to claim 1, wherein the wavelength conversion member is provided at one focal point of the spheroid.   The wavelength conversion element according to claim 2, wherein the wavelength conversion light reflected by the light reflection surface forms an image in a region adjacent to the wavelength conversion member.   The wavelength conversion element according to any one of claims 1 to 3, wherein the light transmission surface has a shape of a part of a spherical surface. The inorganic member includes a first inorganic member, a second inorganic member, and a third inorganic member provided between the first inorganic member and the second inorganic member,
The first inorganic member has the light reflecting surface,
The second inorganic member has the light transmission surface,
The wavelength conversion member is provided between the first inorganic member and the second inorganic member,
The wavelength conversion element according to any one of claims 1 to 4, wherein the third inorganic member is provided on an optical path of the first component.   The wavelength conversion element according to claim 5, wherein a refractive index of the first inorganic member and a refractive index of the second inorganic member are substantially equal to a refractive index of the wavelength conversion member.   The wavelength conversion element according to claim 5 or 6, wherein a refractive index of the first inorganic member and a refractive index of the second inorganic member are substantially equal to a refractive index of the third inorganic member. The wavelength conversion member includes a base material made of an inorganic material, and an activator that becomes a light emission center dispersed in the base material,
The wavelength conversion element according to any one of claims 1 to 4, wherein the inorganic member is made of the inorganic material.   The wavelength conversion element according to any one of claims 1 to 8, further comprising a heat dissipation member thermally connected to the light reflecting surface.   The wavelength conversion element according to any one of claims 1 to 9, wherein the light reflecting surface includes a dielectric multilayer film.   The wavelength conversion element according to claim 10, wherein at least a part of the dielectric multilayer film reflects the wavelength conversion light and transmits excitation light for exciting the wavelength conversion member. The light reflecting surface further includes a metal reflecting film provided so as to surround the dielectric multilayer film,
The wavelength conversion element according to claim 10, wherein the dielectric multilayer film has characteristics of reflecting the wavelength converted light and transmitting excitation light for exciting the wavelength conversion member. The wavelength conversion element according to any one of claims 1 to 12,
A light source device comprising: a light emitting element that emits excitation light for exciting the wavelength conversion member. A light source device according to claim 13;
A light modulation device that forms image light by modulating light from the light source device according to image information;
A projector comprising: a projection optical system that projects the image light.

Images