Illumination device

Abstract

This illumination device includes at least one light source, at least one wavelength conversion member, at least one wavelength separation filter, a light guide member, and a lens optical system. The light source emits excitation light. The excitation light from the light source enters the wavelength conversion member. The wavelength conversion member emits fluorescence having a spectrum different than that of the excitation light on the basis of the excitation light. The wavelength separation filter guides, to the wavelength conversion member, the excitation light from the light source. The fluorescence from the wavelength conversion member enters the wavelength separation filter. The light guide member has a cylindrical surface, and the fluorescence from the wavelength separation filter propagates through the inside of the light guide member surrounded by the cylindrical surface while repeatedly reflecting at the cylindrical surface. The lens optical system includes a lens on which the fluorescence emitted from the light guide member is incident, and the lens optical system causes an image of the emitting surface of the light guide member to be formed on a virtual image surface.

Description

lighting equipment CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority from Japanese Patent Application No. 2022-112160 (filed July 13, 2022), the entire disclosure of which is incorporated herein by reference.

[0002] The present disclosure relates to a lighting device.

[0003] 2. Description of the Related Art Light-emitting devices including a light source, a beam splitter, and a wavelength conversion member have been proposed (for example, see Patent Document 1).

[0004] Japanese Patent Application Laid-Open No. 2014-203852

[0005] A lighting device is disclosed.

[0006] In one embodiment, the lighting device includes one or more light sources, one or more wavelength conversion members, one or more wavelength separation filters, a light-guiding member, and a lens optical system. The light source emits excitation light. The excitation light from the light source is incident on the wavelength conversion member. The wavelength conversion member emits fluorescence having a spectrum different from that of the excitation light based on the excitation light. The wavelength separation filter guides the excitation light from the light source to the wavelength conversion member. The fluorescence from the wavelength conversion member is incident on the wavelength separation filter. The light-guiding member has a cylindrical surface, and the fluorescence from the wavelength separation filter travels inside the cylindrical surface while repeatedly reflecting off the cylindrical surface. The lens optical system includes a lens onto which the fluorescence emitted from the light-guiding member is incident, and forms an image of the emission surface of the light-guiding member on a virtual image plane.

[0007] FIG. 1 is a diagram schematically showing an example of an optical system of an illumination device according to a first embodiment. FIG. 2 is a cross-sectional view schematically showing an example of the configuration of an illumination device according to the first embodiment. FIG. 3 is a graph showing an example of the spectral transmittance of a wavelength separation filter. FIG. 4 is a cross-sectional view showing an enlarged portion of the configuration of an illumination device. FIG. 5 is a diagram schematically showing a first aspect of the optical system of an illumination device according to the first embodiment. FIG. 6 is a diagram schematically showing a second aspect of the optical system of an illumination device according to the first embodiment. FIG. 7 is a diagram schematically showing a third aspect of the optical system of an illumination device according to the first embodiment. FIG. 8 is a diagram schematically showing an example of an optical system of an illumination device according to a second embodiment. FIG. 9 is a diagram schematically showing an example of an arrangement of wavelength conversion members. FIG. 10 is a diagram schematically showing a first aspect of the configuration of an illumination device according to the second embodiment. FIG. 11 is a graph showing an example of the spectral transmittance of first to third wavelength separation filters. FIG. 12 is a diagram schematically showing a second aspect of the optical system of an illumination device according to the second embodiment. FIG. 13 is a diagram schematically showing a third aspect of the optical system of an illumination device according to the second embodiment. 10 is a diagram schematically showing a seventh aspect of the optical system of the illumination device according to the second embodiment. FIG. 11 is a diagram schematically showing an eighth aspect of the optical system of the illumination device according to the second embodiment. FIG. 12 is a diagram schematically showing a ninth aspect of the optical system of the illumination device according to the second embodiment. FIG. 13 is a diagram schematically showing an example of an arrangement of wavelength conversion members and an irradiation area of ​​excitation light. FIG. 14 is a diagram schematically showing an example of a configuration of an illumination device. FIG. 15 is a diagram schematically showing an example of the optical system of the illumination device according to the fourth embodiment. FIG. 16 is a diagram schematically showing another example of the shape of the wavelength conversion member. FIG. 17 is a diagram schematically showing another aspect of the optical system of the illumination device according to the fourth embodiment. FIG. 18 is a diagram schematically showing another example of the shape of the wavelength conversion member.

[0008] The inventor has created a technology for emitting more uniform illumination light in an illumination device. First to fourth embodiments of this technology will be described below with reference to the drawings.

[0009] In the drawings, parts having the same or similar configurations and functions are denoted by the same reference numerals, and duplicate explanations will be omitted below. The drawings are schematic illustrations. A right-handed XYZ coordinate system is appropriately indicated in each drawing. Hereinafter, one side of the X direction will also be referred to as the +X side, and the other side of the X direction will also be referred to as the -X side. The same or similar designations will also be applied to the Y direction and the Z direction.

[0010] 1. First Embodiment 1-1. Schematic Configuration of Illumination Device 1 Fig. 1 is a diagram schematically illustrating an example of an optical system of an illumination device 1. Fig. 2 is a cross-sectional view schematically illustrating an example of the configuration of the illumination device 1.

[0011] As shown in Fig. 2, the lighting device 1 is a device that emits fluorescence L1 as illumination light into an illumination space S1. The lighting device 1 is placed, for example, on the ceiling of the illumination space S1. As shown in Figs. 1 and 2, the lighting device 1 includes a light source 2, a wavelength conversion member 3, a wavelength separation filter 4, a light-guiding member 5, a lens optical system 6, and a housing 7. Below, an example of each component will first be outlined, and then described in detail.

[0012] The housing 7 houses the light source 2, the wavelength conversion member 3, the wavelength separation filter 4, the light-guiding member 5, and the lens optical system 6. The housing 7 has a first opening (hereinafter also referred to as the irradiation opening) 7a at its end on the -Z side, and fluorescence L1 as illumination light is emitted from the irradiation opening 7a into the illumination space S1.

[0013] 1, the light source 2 has an exit portion (e.g., an exit surface) 201 that emits excitation light L0. The excitation light L0 may be light having a peak in the wavelength range of 380 nm to 415 nm, for example. As a specific example, the excitation light L0 may be purple light having a peak near 405 nm. Note that the excitation light L0 is not necessarily limited to purple light, and may be blue light having a peak near 450 nm, for example.

[0014] The excitation light L0 from the light source 2 is incident on the wavelength separation filter 4. The wavelength separation filter 4 guides the excitation light L0 to the wavelength conversion member 3. In the example of FIGS. 1 and 2, the light source 2 and the wavelength separation filter 4 are aligned along a first direction. The first direction is, for example, the X direction. In the example of FIGS. 1 and 2, the wavelength conversion member 3 and the wavelength separation filter 4 are aligned along a second direction that intersects with the first direction. The second direction is, for example, the Z direction. Here, the wavelength separation filter 4 reflects the excitation light L0 from the light source 2 toward the wavelength conversion member 3, and guides the excitation light L0 to the wavelength conversion member 3. The excitation light L0 is incident on the wavelength conversion member 3.

[0015] The wavelength conversion member 3 contains a phosphor. The wavelength conversion member 3 emits fluorescence L1 based on the incident excitation light L0. The fluorescence L1 has a spectrum different from the spectrum of the excitation light L0. Specifically, the peak wavelength of the fluorescence L1 is longer than the peak wavelength of the excitation light L0 (hereinafter also referred to as the excitation peak wavelength), and the fluorescence L1 is visible light. The fluorescence L1 travels from the wavelength conversion member 3 toward the wavelength separation filter 4 and is incident on the wavelength separation filter 4. In the example of FIGS. 1 and 2 , the wavelength separation filter 4 transmits the fluorescence L1 from the wavelength conversion member 3.

[0016] The light-guiding member 5 has a cylindrical surface 5a. In the example of FIGS. 1 and 2 , the central axis of the cylindrical surface 5a is aligned along the Z direction. The fluorescence L1 from the wavelength separation filter 4 travels inside the area surrounded by the cylindrical surface 5a while being repeatedly reflected by the cylindrical surface 5a. As shown in FIG. 2 , the fluorescence L1 emitted from an exit surface 5c (described later) of the light-guiding member 5 travels toward and enters the lens optical system 6.

[0017] The lens optical system 6 includes one or more lenses 61 located between the light-guiding member 5 and the illumination opening 7a. In the example of FIGS. 1 and 2, three lenses 61 are shown. The three lenses 61 are lined up in the Z direction between the light-guiding member 5 and the illumination opening 7a. The lens optical system 6 is an imaging optical system that forms an image of an object plane on a virtual image plane IS1 when the exit surface 5c of the light-guiding member 5 is defined as the object plane. The image plane IS1 is located at the illumination opening 7a, for example. The fluorescence L1 passes through the illumination opening 7a and is irradiated into the illumination space S1.

[0018] As described above, according to the illumination device 1, the fluorescence L1 travels inside the light-guiding member 5 while being reflected by the cylindrical surface 5a of the light-guiding member 5. This makes the intensity distribution of the fluorescence L1 uniform in a cross section (here, the XY cross section) perpendicular to the central axis of the cylindrical surface 5a. Therefore, more uniform fluorescence L1 is emitted from the emission surface 5c of the light-guiding member 5. Consequently, the illumination device 1 can emit more uniform fluorescence L1 as illumination light from the irradiation opening 7a.

[0019] Furthermore, in the lighting device 1, the lens optical system 6 forms an image on the exit surface 5c of the light-guiding member 5 on a virtual image plane IS1. This allows the fluorescence L1 to be reduced in size on the image plane IS1. This makes it less likely that the fluorescence L1 will be reflected or scattered by the inner wall of the irradiation opening 7a of the housing 7, thereby realizing a more uniform, high-quality illumination space S1 with less glare. Furthermore, the presence of the lighting device 1 when viewed from outside the irradiation opening 7a can be reduced.

[0020] An example of each component of the lighting device 1 will be described in detail below.

[0021] <1-1-1. Light Source 2> The light source 2 may include, for example, a semiconductor laser element such as a laser diode (LD), a vertical cavity surface emitting laser (VCSEL), a light emitting diode (LED), or a super luminescent diode (SLD). The emission unit 201 of the light source 2 may be the emission end of a light emitting element. For example, a gallium nitride (GaN) semiconductor laser that emits 405 nm violet laser light as excitation light L0 may be used as the light emitting element.

[0022] Alternatively, the light source 2 may further include a light-guiding member such as a fiber and a rod lens in addition to the light-emitting element. The fiber includes a linear core and cladding. The cladding has a lower refractive index than the core and covers the core. The excitation light L0 can be transmitted through the core while being totally reflected at the boundary between the core and the cladding. The rod lens has, for example, a cylindrical shape. The excitation light L0 can be transmitted through the rod lens while being totally reflected at the side of the rod lens. The incident end of such a light-guiding member corresponds to the first end face of the fiber or the first end face of the rod lens, and the output end of the light-guiding member corresponds to the second end face opposite the first end face of the fiber or the second end face opposite the first end face of the rod lens. The excitation light L0 from the light-emitting element enters the incident end of the light-guiding member, travels through the light-guiding member, and is output from the output end of the light-guiding member. In this case, the output portion 201 of the light source 2 corresponds to the output end of the light-guiding member.

[0023] The light source 2 may emit linearly polarized excitation light L0. The polarization of the excitation light L0 may be, for example, s-polarized with respect to the incident surface of the wavelength separation filter 4. Furthermore, various lenses may be positioned between the light source 2 and the wavelength separation filter 4.

[0024] 1 and 2, the wavelength separation filter 4 is arranged next to the light source 2 at a distance in the X direction, and is located on the +X side of the light source 2. As described above, the wavelength separation filter 4 guides the excitation light L0 from the light source 2 to the wavelength conversion member 3, and the fluorescence L1 from the wavelength conversion member 3 is incident on the wavelength separation filter 4. In the example of FIGS. 1 and 2, the wavelength separation filter 4 reflects the excitation light L0 toward the wavelength conversion member 3 and transmits the fluorescence L1. The wavelength separation filter 4 is also called a dichroic mirror.

[0025] The wavelength separation filter 4 includes, for example, a dielectric multilayer film 401. For example, the dielectric multilayer film 401 has a structure in which a plurality of thin dielectric films are repeatedly stacked. The dielectric film may be, for example, silicon oxide (SiO ２ ), titanium oxide (TiO ２ ), aluminum oxide (Al ２ O ３ ), zirconium oxide (ZrO２ ), tantalum oxide (Ta ２ O ５ ) and niobium oxide (Nb ２ O ３ ) is used. For example, by appropriately setting the thicknesses of the plurality of dielectric thin films that make up the dielectric multilayer film 401, it is possible to achieve a spectral transmittance that reflects the excitation light L0 in the dielectric multilayer film 401 and transmits the fluorescence L1. In other words, the function of the wavelength separation filter 4 is substantially realized by the dielectric multilayer film 401.

[0026] FIG. 3 is a graph showing an example of the spectral transmittance of the wavelength separation filter 4. FIG. 3 shows the transmittance Ts of the wavelength separation filter 4 for s-polarized light and the transmittance Tn of the wavelength separation filter 4 for unpolarized light. Here, the polarization state of the excitation light L0 is s-polarized, and its wavelength is 405 nm. In the example of FIG. 3, the transmittance Ts for the excitation light L0 is almost zero, so the excitation light L0 is hardly transmitted through the wavelength separation filter 4. For simplicity, if the absorption rate of the wavelength separation filter 4 is assumed to be almost zero, the excitation light L0 is reflected by the wavelength separation filter 4 with a reflectance of almost 100%. On the other hand, the polarization state of the fluorescence L1 is unpolarized. The transmittance Tn in the wavelength range of the fluorescence L1 is almost 100%, so the fluorescence L1 is transmitted through the wavelength separation filter 4.

[0027] 1 and 2, the wavelength separation filter 4 is positioned such that the direction along its surface intersects with the X direction at an angle close to approximately 45 degrees. In the example of Figures 1 and 2, the wavelength separation filter 4 extends from the -X and -Z sides toward the +X and +Z sides. Therefore, the traveling direction of the excitation light L0 from the light source 2 changes by approximately 90 degrees before and after the wavelength separation filter 4. Specifically, the excitation light L0 from the light source 2 travels toward the +X side, is reflected by the wavelength separation filter 4, and travels toward the +Z side.

[0028] 1-1-3. Wavelength conversion member 3> In the example of FIGS. 1 and 2, the wavelength conversion member 3 is arranged next to the wavelength separation filter 4 at an interval in the Z direction, and is located on the +Z side of the wavelength separation filter 4.

[0029] The wavelength conversion member 3 contains a fluorescent material. The wavelength conversion member 3 is made of a wavelength conversion material (i.e., a fluorescent material) that converts the excitation light L0 into blue light, such as BaMgAl １０ O １７ :Eu or (Sr, Ca, Ba) １０ (P.O. ４ ) ６ Cl ２ :Eu, (Sr, Ba) １０ (P.O. ４ ) ６ Cl ２ The wavelength conversion member 3 may contain, for example, (Sr, Ba, Ca) as a wavelength conversion material that converts the excitation light L0 into blue-green light. ５ (P.O. ４ ) ３ Cl:Eu,Sr ４ Al １４ O ２５ The wavelength conversion member 3 may contain, for example, SrSi as a wavelength conversion material that converts the excitation light L0 into green light. ２ (O, Cl) ２ N ２ :Eu, (Sr, Ba, Mg) ２ SiO ４ :Eu ２＋ , or ZnS:Cu, Al, Zn ２ SiO ４ The wavelength conversion member 3 may contain, for example, Y:Mn as a wavelength conversion material that converts the excitation light L0 into red light. ２ O ２ S: Eu, Y ２ O ３ :Eu, SrCaClAlSiN ３ :Eu ２＋ , CaAlSiN ３ : Eu or CaAlSi(ON) ３ The wavelength conversion member 3 may contain 3Ga as a wavelength conversion material that converts the excitation light L0 into light having a wavelength in the near-infrared region. ５ O １２:Cr, etc. If the wavelength conversion member 3 contains multiple types of wavelength converting materials corresponding to multiple colors of light, the wavelength conversion member 3 can emit fluorescence L1 with high color rendering. Specifically, if the excitation light L0 is light having a peak in the range of 380 nm to 415 nm and the wavelength conversion member 3 contains phosphors corresponding to red, green, and blue light, the color rendering of the fluorescence L1 can be particularly improved.

[0030] Furthermore, the wavelength conversion member 3 may contain a resin such as a binder for binding the fine particles of the phosphor together.

[0031] The wavelength conversion member 3 has, for example, a surface 3a, a surface 3b, and a side surface 3c. The surface 3b is the surface of the wavelength conversion member 3 facing the wavelength separation filter 4. The surface 3a is the surface of the wavelength conversion member 3 opposite to the surface 3b. The side surface 3c is a side surface connecting the periphery of the surface 3a and the periphery of the surface 3b of the wavelength conversion member 3. The wavelength conversion member 3 may have a plate-like shape. That is, the surfaces 3a and 3b of the wavelength conversion member 3 may be substantially flat surfaces and substantially parallel to each other. The wavelength conversion member 3 may be positioned such that its thickness direction is along the Z direction. That is, the surfaces 3a and 3b of the wavelength conversion member 3 may be substantially parallel to the XY plane.

[0032] 1 and 2, the light-guiding member 5 may include a first transparent member 51 and a second transparent member 52. The first transparent member 51 and the second transparent member 52 may be made of, for example, at least one of glass, such as optical glass, and resin, such as acrylic resin. The dielectric multilayer film 401 of the wavelength separation filter 4 is located between the first transparent member 51 and the second transparent member 52. The first transparent member 51 and the second transparent member 52 also function as a base material supporting the dielectric multilayer film 401. Such a light-guiding member 5 also functions as a rod lens incorporating the wavelength separation filter 4.

[0033] The entire first transparent member 51 and the second transparent member 52 (i.e., the light-guiding member 5) may have, for example, a columnar shape. As a specific example, the light-guiding member 5 may have a quadrangular prism shape. The central axis of the light-guiding member 5 is, for example, substantially parallel to the Z direction. The light-guiding member 5 has a cylindrical surface 5a, an end surface 5b, and an exit surface 5c. The end surface 5b and the exit surface 5c are end surfaces located on both sides of the light-guiding member 5 in the longitudinal direction (i.e., the Z direction). The exit surface 5c is located on the −Z side of the end surface 5b, i.e., on the lens optical system 6 side. The cylindrical surface 5a is a side surface connecting the periphery of the end surface 5b and the periphery of the exit surface 5c of the light-guiding member 5. The end surface 5b and the exit surface 5c may be, for example, flat surfaces or may be substantially parallel to each other. Furthermore, as shown in FIGS. 1 and 2, the end surface 5b of the light-guiding member 5 may be substantially parallel to the surface 3b of the wavelength conversion member 3. When the light guide member 5 has a quadrangular prism shape, the end face 5b and the light exit surface 5c have a quadrangular shape when viewed along the Z direction.

[0034] The first transparent member 51 and the second transparent member 52 are members obtained by dividing the light-guiding member 5 in two at the dielectric multilayer film 401 as a boundary. The first transparent member 51 has a first side surface 51a, which is a part of the cylindrical surface 5a, a first inclined surface 51b, and an exit surface 5c. The first inclined surface 51b and the exit surface 5c are end surfaces located on both sides of the first transparent member 51 in the Z direction. The first inclined surface 51b is inclined with respect to the X direction at the same angle as the dielectric multilayer film 401. The exit surface 5c is located on the lens optical system 6 side relative to the first inclined surface 51b. The first side surface 51a is a side surface connecting the periphery of the first inclined surface 51b and the periphery of the exit surface 5c of the first transparent member 51. Such a first transparent member 51 has, for example, a columnar shape in which both end surfaces in the Y direction are right-angled trapezoids.

[0035] The second transparent member 52 has a second side surface 52a, which is the remaining portion of the cylindrical surface 5a, an end surface 5b, and a second inclined surface 52c. The second inclined surface 52c is inclined at the same degree as the first inclined surface 51b of the first transparent member 51 and faces the first inclined surface 51b. The second inclined surface 52c is approximately parallel to the first inclined surface 51b. The +X side end of the second inclined surface 52c is connected to the +X side end of the end surface 5b. The second side surface 52a is a side surface that connects the end surface 5b of the second transparent member 52 and the second inclined surface 52c. Such a second transparent member 52 has, for example, a columnar shape in which both end surfaces in the Y direction form a right-angled triangle.

[0036] The dielectric multilayer film 401 of the wavelength separation filter 4 is located between the first inclined surface 51b of the first transparent member 51 and the second inclined surface 52c of the second transparent member 52. In other words, the first inclined surface 51b and the second inclined surface 52c sandwich the dielectric multilayer film 401 therebetween. The dielectric multilayer film 401 is formed on one of the first inclined surface 51b and the second inclined surface 52c. For example, the dielectric multilayer film 401 is formed by a physical vapor deposition method such as vacuum deposition, sputtering, or ion plating, or a chemical vapor deposition method (CVD).

[0037] The first transparent member 51 and the second transparent member 52 may be fixed to each other via a fixing agent such as a transparent adhesive. For example, the dielectric multilayer film 401 may be formed on one of the first inclined surface 51 b and the second inclined surface 52 c, and the adhesive may be located between the other of the first inclined surface 51 b and the second inclined surface 52 c and the dielectric multilayer film 401. For example, a resin such as a photocurable resin may be used as the adhesive.

[0038] The excitation light L0 from the light source 2 is incident on the second side surface 52a of the second transparent member 52 and travels from the second side surface 52a through the interior of the second transparent member 52 toward the wavelength separation filter 4. The excitation light L0 is reflected by the wavelength separation filter 4 and travels through the interior of the second transparent member 52 toward the end surface 5b. The excitation light L0 is emitted from the end surface 5b toward the wavelength conversion member 3 and is incident on the surface 3b of the wavelength conversion member 3. In other words, the end surface 5b can function as an emission surface for the excitation light L0.

[0039] In the example of FIGS. 1 and 2 , fluorescence L1 from the wavelength conversion member 3 travels while spreading toward the second transparent member 52 and is incident on the end face 5b of the second transparent member 52. The fluorescence L1 is refracted at the end face 5b and travels inside the second transparent member 52 toward the wavelength separation filter 4. In other words, the end face 5b also functions as the incident surface for the fluorescence L1. The refraction at the end face 5b reduces the spread angle of the fluorescence L1. In other words, the end face 5b can function as the end face of a focusing lens. The fluorescence L1 passes through the wavelength separation filter 4 and travels inside the first transparent member 51 toward the exit surface 5c. The fluorescence L1 is emitted from the exit surface 5c toward the lens optical system 6.

[0040] The fluorescence L1 travels from the end face 5b toward the exit surface 5c while repeatedly reflected by the cylindrical surface 5a of the light-guiding member 5. As the fluorescence L1 is repeatedly reflected, the intensity distribution of the fluorescence L1 in a cross section perpendicular to the longitudinal direction (here, the Z direction) of the light-guiding member 5 becomes uniform. As a result, more uniform fluorescence L1 is emitted from the exit surface 5c of the light-guiding member 5. Furthermore, color unevenness of the fluorescence L1 on the exit surface 5c can also be reduced.

[0041] The uniformity of the fluorescence L1 at the emission surface 5c can be improved by designing the light guide member 5 to be long. The length of the light guide member 5 in the Z direction may be, for example, 10 mm or more.

[0042] 1 and 2, the first transparent member 51 from the wavelength separation filter 4 to the exit surface 5c is a single piece. Here, "single piece" refers to, for example, an object made of a single member, not multiple members. If the first transparent member 51 is a single piece, there is no interface (adhesive surface) between different members in the region from the wavelength separation filter 4 to the exit surface 5c. This reduces the loss of the fluorescence L1, allowing the illumination device 1 to emit the fluorescence L1 into the illumination space S1 with higher efficiency.

[0043] 1 and 2 , the area of ​​the end face 5b of the light-guiding member 5 may be equal to or larger than the area of ​​the surface 3b of the wavelength conversion member 3. For example, when the surface 3b of the wavelength conversion member 3 and the end face 5b of the light-guiding member 5 have a rectangular shape, the diagonal of the surface 3b may be approximately 2 mm to 4 mm, and the diagonal of the end face 5b may be approximately 4 mm to 15 mm or more. This allows more of the fluorescence L1 that spreads and travels from the surface 3b of the wavelength conversion member 3 to be incident on the end face 5b of the light-guiding member 5. Consequently, the lighting device 1 can emit the fluorescence L1 into the illumination space S1 with higher efficiency.

[0044] As shown in Figures 1 and 2, the wavelength conversion member 3 and the second transparent member 52 may be spaced apart from each other. The first distance between the surface 3b of the wavelength conversion member 3 and the end face 5b of the second transparent member 52 may be narrower than the second distance between the lens optical system 6 and the irradiation opening 7a, for example. The second distance is the distance between the lens 61 of the lens optical system 6 that is closest to the irradiation opening 7a and the irradiation opening 7a, for example. The first distance can be 5 mm or less, for example. The second distance can be 10 mm or more, for example. If the first distance is narrow, more of the fluorescence L1 that spreads and travels from the wavelength conversion member 3 can be incident on the end face 5b of the second transparent member 52.

[0045] 1 and 2 , no other optical element (e.g., a lens) may be positioned between the wavelength conversion member 3 and the second transparent member 52. This makes it easier to set the first gap between the wavelength conversion member 3 and the second transparent member 52 narrow.

[0046] <1-1-5. Lens Optical System 6> In the example shown in FIGS. 1 and 2, the lens optical system 6 is aligned with the light-guiding member 5 at a distance in the Z direction and is located on the -Z side of the light-guiding member 5. The lens 61 of the lens optical system 6 is located between the exit surface 5c of the light-guiding member 5 and the irradiation opening 7a of the housing 7. The lens 61 is formed of a material containing at least one of glass, such as optical glass, and resin, such as acrylic resin. As shown in FIGS. 1 and 2, each lens 61 may be, for example, a biconvex lens. In the example shown in FIGS. 1 and 2, the optical axis of the lens 61 is aligned along the Z direction. In other words, in the example shown in FIGS. 1 and 2, the Z direction is the optical axis direction of the lens optical system 6. Note that the lens 61 is not limited to a convex lens, and may be a concave lens or a meniscus lens. The lens 61 may also be a spherical lens or an aspherical lens.

[0047] The lens optical system 6 is an imaging optical system that forms an image of the object plane on a virtual image plane IS1 when the exit surface 5c of the light-guiding member 5 is the object plane. That is, in the example shown in FIGS. 1 and 2 , three lenses 61 constitute the imaging optical system. The lenses 61 (particularly the lens 61 closest to the illumination opening 7a) may also be referred to as imaging lenses. In the illumination device 1, the exit surface 5c of the light-guiding member 5 has a conjugate relationship with the image plane IS1. Note that the term "conjugate relationship" is not used in a strict sense; rather, the portion on the illumination opening 7a side of the exit surface 5c of the light-guiding member 5 where the fluorescence L1 is most concentrated (the portion where the magnitude of the fluorescence L1 in the cross section perpendicular to the optical axis of the lens optical system 6 is smallest) can be considered to be the image plane IS1.

[0048] The image plane IS1 may be located at the illumination opening 7a, for example. The image plane IS1 may be a flat surface or a curved surface. The fluorescence L1 is collected at the image plane IS1 and emitted into the illumination space S1 through the illumination opening 7a. The image plane IS1 does not necessarily have to be located inside the illumination opening 7a. The image plane IS1 may be located slightly offset from the illumination opening 7a in the traveling direction (here, the Z direction) of the fluorescence L1 passing through the illumination opening 7a. In other words, the image plane IS1 may be located slightly inside the housing 7 relative to the illumination opening 7a, or slightly toward the illumination space S1.

[0049] In this illumination device 1, the imaging magnification of the lens optical system 6 is equal to or less than the ratio (M3 / M1) of the size M3 of the irradiation opening 7a to the size M1 of the fluorescence L1 at the exit surface 5c of the light-guiding member 5. The size M1 of the fluorescence L1 at the exit surface 5c of the light-guiding member 5 may be, for example, the size of the exit surface 5c of the light-guiding member 5 itself. The size M3 of the irradiation opening 7a is the opening area of ​​the irradiation opening 7a as viewed along the Z direction. If the shape of the irradiation opening 7a as viewed along the Z direction is circular or rectangular, the diameter or diagonal length of the irradiation opening 7a may be, for example, approximately 5 mm to 15 mm. Note that if the surface forming the irradiation opening 7a is inclined, the size M3 of the irradiation opening 7a will vary at each position in the Z direction. In this case, for example, the minimum value of the size M3 of the irradiation opening 7a may be used.

[0050] The imaging magnification is the ratio of the size M2 of the fluorescence L1 on the image plane IS1 to the size M1 of the fluorescence L1 on the exit surface 5c of the light guide member 5.

[0051] The magnitude of the fluorescence L1 is determined by the peak value e in the light intensity distribution of the fluorescence L1 in a cross section perpendicular to the Z direction. ２ Here, "e" is called the Napier's number. In other words, the outermost rays of the fluorescence L1 in FIG. 2 are defined by a contour line having a peak value e of the light intensity distribution in a cross section perpendicular to the optical axis AX1. ２ The light in the area outside the area surrounded by the contour lines (i.e., both outer light rays) may be regarded as noise light.

[0052] If the imaging magnification is equal to or less than the above ratio, the size M2 of the fluorescence L1 on the image plane IS1 can be made equal to or less than the size M3 of the irradiation opening 7a, thereby reducing the possibility that the fluorescence L1 will be incident on the peripheral portion of the irradiation opening 7a in the housing 7. This reduces unnecessary reflected and scattered light leaking from the irradiation opening 7a.

[0053] Furthermore, the imaging magnification of the lens optical system 6 may be set so that the size of the fluorescence L1 passing through the irradiation opening 7a is smaller than the size of the irradiation opening 7a, thereby further reducing reflected and scattered light.

[0054] FIG. 4 is an enlarged cross-sectional view showing a portion of the configuration of the illumination device 1. In the illumination device 1, the spread angle θ1 of the fluorescence L1 emitted from the exit surface 5c of the light-guiding member 5 may be equal to or smaller than the angle φ1 that defines the numerical aperture of the lens optical system 6. The numerical aperture is the product of the sine of half the value of the angle φ1 and the refractive index. The angle φ1 here is, for example, the angle formed by both outer rays of virtual light passing through the effective area of ​​the lens optical system 6. The effective area here corresponds to the area through which light passes through which the optical performance of the lens optical system 6 can be exhibited. For example, the effective area of ​​the lens 61 is the area of ​​the lens 61 excluding a predetermined peripheral width. As a more specific example, the effective area of ​​the lens 61 may be the area surrounded by the inner peripheral edge of the part of the housing 7 that holds the peripheral edge of the lens 61 (i.e., the lens holder).

[0055] Because the spread angle θ1 is equal to or smaller than the angle φ1, the fluorescence L1 can pass through the effective area of ​​the lens optical system 6. Therefore, almost no fluorescence L1 is incident on the edge of the lens 61, and unnecessary reflection and scattering of the fluorescence L1 at the edge can be suppressed or avoided.

[0056] As described above, in the illumination device 1, the imaging magnification of the lens optical system 6 may be equal to or less than the above ratio, and the divergence angle θ1 may be equal to or less than the angle φ1. This suppresses or avoids unnecessary reflection and scattering of the fluorescence L1 at the lens optical system 6 and the periphery of the irradiation opening 7a. Therefore, the illumination device 1 can emit most of the fluorescence L1 from the light-guiding member 5 into the illumination space S1 through the irradiation opening 7a. In other words, the amount of fluorescence L1 emitted into the illumination space S1 can be improved. Furthermore, since the reflected and scattered light leaking into the illumination space S1 can be reduced, unevenness such as glare in the fluorescence L1 emitted into the illumination space S1 can be suppressed. In other words, the uniformity of the fluorescence L1 can be further improved. Therefore, the illumination device 1 can irradiate the illumination space S1 with highly efficient and high-quality fluorescence L1.

[0057] Furthermore, the spread angle θ2 (see FIG. 2 ) of the fluorescence L1 in the illumination space S1 may be smaller than the spread angle θ1 of the fluorescence L1 incident on the lens optical system 6 from the exit surface 5c of the light-guiding member 5. In other words, the lens optical system 6 may be designed so that the spread angle θ2 is smaller than the spread angle θ1. As a specific example, the orientation angle (e.g., half-value angle) of the fluorescence L1 in the illumination space S1 is, for example, approximately 60 degrees or less. The orientation angle of the lighting device 1 may be, for example, less than 45 degrees, less than 30 degrees, or less than 15 degrees. This can reduce the glare of the lighting devices 1 that enter the field of view in an illumination space S1 in which, for example, multiple lighting devices 1 are installed at regular intervals. As a result, the comfort of the illumination space S1 can be improved.

[0058] <1-2. First Aspect> FIG. 5 is a diagram schematically illustrating a first aspect of the optical system of the illumination device 1 according to the first embodiment. As shown in FIG. 5, the light source 2, wavelength separation filter 4, and wavelength conversion member 3 may be aligned in the X direction. In the example of FIG. 5, the light source 2 is located on the −X side of the wavelength separation filter 4, and the wavelength conversion member 3 is located on the +X side of the wavelength separation filter 4. Therefore, in this structure, the wavelength separation filter 4 transmits the excitation light L0 from the light source 2 toward the wavelength conversion member 3. The excitation light L0 transmitted through the wavelength separation filter 4 is incident on the wavelength conversion member 3. The fluorescence L1 emitted by the wavelength conversion member 3 travels toward the wavelength separation filter 4 and is incident on the wavelength separation filter 4. The wavelength separation filter 4 reflects the fluorescence L1 toward the −Z side. The fluorescence L1 reflected by the wavelength separation filter 4 travels inside the light-guiding member 5 toward the emission surface 5c while repeatedly reflected by the cylindrical surface 5a of the light-guiding member 5.

[0059] <1-3. Second Aspect> Fig. 6 is a diagram schematically illustrating a second aspect of the optical system of the illumination device 1 according to the first embodiment. As shown in Fig. 6, the wavelength separation filter 4 may include a dichroic prism incorporating a dielectric multilayer film 401. Specifically, the wavelength separation filter 4 includes the dielectric multilayer film 401, a first prism 402, and a second prism 403. The first prism 402 and the second prism 403 may be made of, for example, at least one of glass such as optical glass and resin such as acrylic resin.

[0060] The second prism 403 has a side surface 403a, an end surface 403b, and a second inclined surface 403c. The second prism 403 may have the same shape as the second transparent member 52 in FIG. 1 . That is, the side surface 403a may be the same as the second side surface 52a of the second transparent member 52, the end surface 403b may be the same as the end surface 5b of the second transparent member 52, and the second inclined surface 403c may be the same as the second inclined surface 52c of the second transparent member 52. Such a second prism 403 may have, for example, a right-angled triangular prism shape in which both end surfaces in the Y direction are right-angled triangles. In the example of FIG. 6 , the end surface 403b of the second prism 403 faces the surface 3b of the wavelength conversion member 3 in the Z direction.

[0061] The first prism 402 has a side surface 402a, a first inclined surface 402b, and an end surface 402c. The first inclined surface 402b is inclined to the same extent as the second inclined surface 403c of the second prism 403 and faces the second inclined surface 403c. The first inclined surface 402b is approximately parallel to the second inclined surface 403c. The end surface 402c is located on the light-guiding member 5 side of the first inclined surface 402b. The end surface 402c may be a flat surface approximately parallel to the XY plane. In the example of FIG. 6 , the −X side end of the end surface 402c is connected to the −X side end of the first inclined surface 402b. The side surface 402a is a side surface that connects the first inclined surface 402b and the end surface 402c of the first prism 402. The first prism 402 has a right-angled triangular prism shape with right-angled triangular end faces on both sides in the Y direction.

[0062] The dielectric multilayer film 401 is located between the first inclined surface 402b of the first prism 402 and the second inclined surface 403c of the second prism 403. For example, the dielectric multilayer film 401 is formed on one of the first inclined surface 402b and the second inclined surface 403c. The first prism 402 and the second prism 403 may be fixed to each other via a fixing agent such as a transparent adhesive. In this case, an adhesive may be located between the other of the first inclined surface 402b and the second inclined surface 403c and the dielectric multilayer film 401.

[0063] Such a wavelength separation filter 4 corresponds to the member having the dielectric multilayer film 401 among the members obtained by dividing the light guide member 5 in FIG. 1 in two at the XY cross section.

[0064] In the example of Fig. 6, the light-guiding member 5 includes a rod lens having a cylindrical shape. An end face 5b of the light-guiding member 5 (i.e., the rod lens) is located away from the wavelength separation filter 4 in the Z direction. The end face 5b of the light-guiding member 5 faces the end face 402c of the first prism 402 and is, for example, approximately parallel to the end face 402c. The fluorescence L1 from the wavelength separation filter 4 is incident on the end face 5b of the light-guiding member 5. The exit surface 5c is the side of the light-guiding member 5 opposite the end face 5b, that is, the surface on the lens optical system 6 side. The exit surface 5c is, for example, approximately parallel to the end face 5b. The cylindrical surface 5a of the light-guiding member 5 is a side surface connecting the periphery of the end face 5b and the periphery of the exit surface 5c.

[0065] The wavelength separation filter 4 may be fixed to the light-guiding member 5 via a fixing agent such as a transparent adhesive. In this case, the adhesive may be located between the end face 402c of the first prism 402 and the end face 5b of the light-guiding member 5.

[0066] The dichroic prism that is the wavelength separation filter 4 according to the second aspect is already available, and the rod lens that is the light guiding member 5 is also already available. That is, the existing wavelength separation filter 4 and light guiding member 5 can be used in the lighting device 1. Therefore, the manufacturing cost of the lighting device 1 according to the second aspect can be reduced.

[0067] In the second aspect, the area of ​​the end face 403b of the second prism 403 may be equal to or larger than the area of ​​the surface 3b of the wavelength conversion member 3. Furthermore, the first distance between the end face 403b of the second prism 403 and the surface 3b of the wavelength conversion member 3 may be narrower than the second distance between the lens optical system 6 and the irradiation opening 7a, for example. This allows a larger amount of light of the fluorescence L1 from the wavelength conversion member 3 to be incident on the end face 403b of the second prism 403.

[0068] <1-4. Third Aspect> Fig. 7 is a diagram schematically illustrating a third aspect of the optical system of the illumination device 1 according to the first embodiment. As shown in Fig. 7, the wavelength separation filter 4 may have a plate-like shape. Specifically, the wavelength separation filter 4 includes a dielectric multilayer film 401 and a transparent substrate 404. The transparent substrate 404 may be made of, for example, at least one of glass such as optical glass and resin such as acrylic resin.

[0069] The transparent substrate 404 is arranged next to the light-guiding member 5 at a distance in the Z direction. The transparent substrate 404 has a plate-like shape and has a surface 404a (corresponding to a first surface) and a surface 404b (corresponding to a second surface). The surface 404b is the surface of the transparent substrate 404 opposite to the surface 404a. The surfaces 404a and 404b are approximately parallel to each other and are inclined at approximately 45 degrees with respect to the X direction. The dielectric multilayer film 401 is located on the surface 404a or the surface 404b of the transparent substrate 404, for example.

[0070] As described above, according to the third aspect, the dielectric multilayer film 401 is located on the plate-shaped transparent substrate 404. This allows the volume of the transparent member to be small, and the manufacturing cost of the wavelength separation filter 4 can be reduced.

[0071] In the third aspect, a condensing lens may be located between the wavelength separation filter 4 and the wavelength conversion member 3. The fluorescence L1 from the wavelength conversion member 3 enters the wavelength separation filter 4 through the condensing lens. This allows more of the fluorescence L1 from the wavelength conversion member 3 to enter the wavelength separation filter 4.

[0072] <1-5. Others> In the above example, the light-guiding member 5 is a so-called rod lens, but its shape may be changed as appropriate. For example, the light-guiding member 5 may have a prismatic shape such as a triangular prism, a quadrangular prism, a pentagonal prism, or a hexagonal prism, or may have a cylindrical shape.

[0073] Furthermore, the light-guiding member 5 is not limited to a rod lens, and may be another type of light-guiding member. For example, the light-guiding member 5 may be a fiber. A fiber includes a linear core and a cladding. The cladding has a lower refractive index than the core and covers the core. The fluorescence L1 can be transmitted through the core while being totally reflected by the cylindrical surface that is the boundary between the core and the cladding. Even when the light-guiding member 5 is a fiber, the dielectric multilayer film 401 of the wavelength separation filter 4 may be built in.

[0074] Furthermore, the light-guiding member 5 may be, for example, a lens barrel. The lens barrel has a cylindrical shape, and the cylindrical surface, which is the inner peripheral surface, is reflective. The fluorescence L1 can pass through the interior of the lens barrel while being totally reflected by the inner peripheral surface of the lens barrel. In this structure, the light-guiding member 5 may have a rectangular cylindrical shape, such as a triangular cylindrical shape, a square cylindrical shape, a pentagonal cylindrical shape, or a hexagonal cylindrical shape, or may have a cylindrical shape.

[0075] 8 is a diagram schematically illustrating an example of an optical system of an illumination device 1A according to a second embodiment. The illumination device 1A according to the second embodiment differs from the illumination device 1 according to the first embodiment in the number of wavelength conversion members 3 and light sources 2.

[0076] The lighting device 1A includes a plurality of wavelength conversion members 3. In the example of FIG. 8 , a first wavelength conversion member 31, a second wavelength conversion member 32, and a third wavelength conversion member 33 are shown as the plurality of wavelength conversion members 3. The first to third wavelength conversion members 31 to 33 emit fluorescence L1 having different spectra from one another. For example, the first wavelength conversion member 31 includes a phosphor of a first color and emits fluorescence L1 of the first color. The first color is, for example, red. The second wavelength conversion member 32 includes a phosphor of a second color and emits fluorescence L1 of the second color. The second color is, for example, green. The third wavelength conversion member 33 includes a phosphor of a third color and emits fluorescence L1 of the third color. The third color is, for example, blue.

[0077] As shown in FIG. 8 , the structure including the first wavelength conversion member 31 to the third wavelength conversion member 33 may face the wavelength separation filter 4 in the Z direction. In the example of FIG. 8 , the structure faces the end surface 5b of the light-guiding member 5 in the Z direction. Also, in the example of FIG. 8 , the first wavelength conversion member 31 to the third wavelength conversion member 33 are arranged in this order in the X direction. In the example of FIG. 8 , the first wavelength conversion member 31 is located furthest on the −X side, and the third wavelength conversion member 33 is located furthest on the +X side. The first wavelength conversion member 31 may be adjacent to the second wavelength conversion member 32 and be in contact with each other, and the second wavelength conversion member 32 may be adjacent to the third wavelength conversion member 33 and be in contact with each other. The first wavelength conversion member 31 to the third wavelength conversion member 33 correspond to, for example, members obtained by dividing the wavelength conversion member 3 of FIG. 1 into three equal parts in the X direction.

[0078] As shown in Fig. 8 , a plurality of light sources 2 may be positioned in one-to-one correspondence with a plurality of wavelength conversion members 3. In the example of Fig. 8 , a first light source 21, a second light source 22, and a third light source 23 are positioned as the plurality of light sources 2. As shown in Fig. 8 , a structure including the first light source 21 to the third light source 23 may be aligned with the wavelength separation filter 4 in the X direction. Furthermore, the first light source 21 to the third light source 23 may be aligned in the Z direction. In the example of Fig. 8 , the first light source 21 is positioned furthest on the -Z side, and the third light source 23 is positioned furthest on the +Z side.

[0079] 8 , the excitation light L0 emitted from the first light source 21 is incident on the wavelength separation filter 4 and is guided by the wavelength separation filter 4 to the first wavelength conversion member 31. In the example of Fig. 8 , the excitation light L0 from the first light source 21 is incident on the second side surface 52a of the second transparent member 52 and travels from the second side surface 52a inside the second transparent member 52 toward the wavelength separation filter 4. The excitation light L0 is reflected by the wavelength separation filter 4 and travels inside the second transparent member 52 toward the end surface 5b. The excitation light L0 travels from the end surface 5b toward the first wavelength conversion member 31 and is incident on the first wavelength conversion member 31.

[0080] The excitation light L0 emitted by the second light source 22 is incident on the wavelength separation filter 4 and is guided by the wavelength separation filter 4 to the second wavelength conversion member 32. The excitation light L0 emitted by the third light source 23 is incident on the wavelength separation filter 4 and is guided by the wavelength separation filter 4 to the third wavelength conversion member 33.

[0081] The first wavelength conversion member 31 emits fluorescence L1 of a first color based on the excitation light L0 incident thereon. The second wavelength conversion member 32 emits fluorescence L1 of a second color based on the excitation light L0 incident thereon. The third wavelength conversion member 33 emits fluorescence L1 of a third color based on the excitation light L0 incident thereon. The fluorescence L1 emitted from the first wavelength conversion member 31 to the third wavelength conversion member 33 spreads and travels toward the end face 5b of the second transparent member 52, where it is incident on the end face 5b of the second transparent member 52. The fluorescence L1 is refracted at the end face 5b and travels inside the second transparent member 52 toward the wavelength separation filter 4. The fluorescence L1 passes through the wavelength separation filter 4 and travels inside the first transparent member 51 toward the exit surface 5c. The fluorescence L1 travels inside the light-guiding member 5 toward the exit surface 5c while repeatedly reflecting off the cylindrical surface 5a, causing the fluorescence L1 of the first to third colors to spatially mix. Therefore, the fluorescence L1 having a color in which the first color to the third color are mixed is emitted from the emission surface 5c of the light-guiding member 5. Therefore, the illumination device 1A can emit the fluorescence L1 having a color in which the first color to the third color are mixed from the irradiation opening 7a.

[0082] The first light source 21 to the third light source 23 may each emit excitation light L0 with a variable light intensity. For example, the first light source 21 includes a first light-emitting element such as an LD, VCSEL, SLD, or LED, and a first drive circuit that drives the first light-emitting element. The first drive circuit includes, for example, a switching power supply circuit and supplies variable power to the first light-emitting element. The first light-emitting element emits excitation light L0 based on the power. Like the first light source 21, the second light source 22 also includes a second light-emitting element and a second drive circuit, and the third light source 23 also includes a third light-emitting element and a third drive circuit.

[0083] 8, the first light source 21, the second light source 22, and the third light source 23 are controlled by a control unit 8. For example, a control board or a microcomputer is used as the control unit 8. For example, a large scale integrated circuit (LSI) in which a central processing unit (CPU), a memory, etc. are integrated is used as the microcomputer.

[0084] Controller 8 may also be referred to as control circuitry. Controller 8 includes at least one processor to provide control and processing power for performing various functions, as described in more detail below.

[0085] According to various embodiments, the at least one processor may be implemented as a single integrated circuit (IC) or as multiple communicatively connected integrated circuits ICs and / or discrete circuits. The at least one processor may be implemented according to various known techniques.

[0086] In one embodiment, a processor includes one or more circuits or units configured to perform one or more data computational procedures or processes, for example, by executing instructions stored in associated memory. In other embodiments, a processor may be firmware (e.g., discrete logic components) configured to perform one or more data computational procedures or processes.

[0087] According to various embodiments, the processor may include one or more processors, controllers, microprocessors, microcontrollers, application specific integrated circuits (ASICs), digital signal processors, programmable logic devices, field programmable gate arrays, or any combination of these devices or configurations, or other known combinations of devices and configurations, to perform the functions described below.

[0088] All or part of the functions of the control unit 8 may be realized by a hardware circuit that does not require software to realize the function.

[0089] The control unit 8 can output control signals individually to the first drive circuit, the second drive circuit, and the third drive circuit. The control signals correspond to target values ​​of the light intensity of the excitation light L0 emitted from the first light source 21, the second light source 22, and the third light source 23. The control unit 8 may control the operation of the first drive circuit in response to a signal from an external device (e.g., a lighting switch) of the lighting device 1A. For example, the control unit 8 receives a signal indicating the target value of the excitation light L0 from the external device and outputs a control signal corresponding to the signal to the first drive circuit. The first drive circuit drives the first light-emitting element based on the control signal, causing the first light-emitting element to emit excitation light L0 having a light intensity close to the target value. The control unit 8 can also control the operation of the second drive circuit and the third drive circuit in the same way as the first drive circuit.

[0090] This allows the control unit 8 to individually adjust the light intensity of the fluorescence L1 emitted from the first wavelength conversion member 31 to the third wavelength conversion member 33. In other words, the control unit 8 can change the proportions of the first color fluorescence L1, the second color fluorescence L1, and the third color fluorescence L1 in the fluorescence L1 emitted by the lighting device 1A. This allows the lighting device 1A to adjust the color of the fluorescence L1 emitted into the illumination space S1.

[0091] Moreover, in the above example, a single wavelength separation filter 4 is positioned for a plurality of wavelength conversion members 31. Therefore, the manufacturing cost of the lighting device 1A can be reduced compared to a structure in which a plurality of wavelength separation filters 4 corresponding to a plurality of wavelength conversion members 31 are used.

[0092] 2-1. Arrangement Pattern of Wavelength Conversion Members FIG. 9 is a diagram schematically illustrating an example of the arrangement of wavelength conversion members 3. FIG. 9 illustrates the shape of the wavelength conversion members 3 as viewed along the Z direction. As shown in FIG. 9( a), each of the first wavelength conversion member 31, the second wavelength conversion member 32, and the third wavelength conversion member 33 may have a rectangular shape as viewed along the Z direction. The first wavelength conversion member 31 to the third wavelength conversion member 33 are arranged in this order in the short-side direction. In the example of FIG. 9, the short-side direction is the X direction. As shown in FIG. 9( a), the second wavelength conversion member 32 may be adjacent to and in contact with the first wavelength conversion member 31 and the third wavelength conversion member 33. In the example of FIG. 9( a), the structure including the first wavelength conversion member 31 to the third wavelength conversion member 33 has a rectangular shape. As shown in FIG. 9A, the first to third wavelength conversion members 31 to 33 may have approximately the same area and may have the same shape.

[0093] As shown in FIG. 9( b), the areas of the first wavelength conversion member 31, the second wavelength conversion member 32, and the third wavelength conversion member 33 may be different. For example, the area of ​​the second wavelength conversion member 32 that emits fluorescence L1 of the second color (here, green) may be larger than the areas of both the first wavelength conversion member 31 and the third wavelength conversion member 33. Because the luminosity of green is high, a structure in which the area of ​​the second wavelength conversion member 32 that emits green fluorescence L1 as the second color is large allows the lighting device 1 to emit fluorescence L1 with higher luminance. As shown in FIG. 9( b), the first wavelength conversion member 31 and the third wavelength conversion member 33 may have approximately the same area or the same rectangular shape. 9(b), the first wavelength conversion member 31 and the third wavelength conversion member 33 are adjacent to each other in the Y direction, for example, and the second wavelength conversion member 32 is adjacent to both the first wavelength conversion member 31 and the third wavelength conversion member 33 in the X direction, for example. The second wavelength conversion member 32 may have the same rectangular shape as the overall shapes of the first wavelength conversion member 31 and the third wavelength conversion member 33. In the example of FIG. 9(b), the structure including the first wavelength conversion member 31 to the third wavelength conversion member 33 also has a rectangular shape.

[0094] Furthermore, among the multiple wavelength conversion members 3, the area of ​​the wavelength conversion members 3 containing fluorescent materials with low heat resistance may be larger than the area of ​​the wavelength conversion members 3 containing fluorescent materials with higher heat resistance than the fluorescent materials. In this case, the excitation light L0 can be incident on a wider irradiation area of ​​the wavelength conversion members 3 with larger areas and lower heat resistance. Therefore, even if the power density of the excitation light L0 to the wavelength conversion members 3 is reduced, the wavelength conversion members 3 can emit a sufficient amount of fluorescence L1. Furthermore, reducing the power density of the excitation light L0 can mitigate the temperature rise of the wavelength conversion members 3. Therefore, even wavelength conversion members 3 with low heat resistance can emit fluorescence L1 with high reliability. On the other hand, by reducing the area of ​​the wavelength conversion members with high heat resistance, the amount of fluorescent material can be reduced, thereby reducing the manufacturing cost of the lighting device 1A.

[0095] 9(b), the area of ​​the second wavelength conversion member 32 is large, so that the excitation light L0 can be incident over a wider range on the second wavelength conversion member 32. This makes it possible to realize an illumination device 1A that is suitable for situations in which the second color fluorescence L1 is used frequently.

[0096] As shown in Fig. 9(c) , each of the first to third wavelength conversion members 31 to 33 may have a circular shape. The first to third wavelength conversion members 31 to 33 may be in contact with each other. In the example of Fig. 9(c) , the first to third wavelength conversion members 31 to 33 have approximately the same area.

[0097] As shown in Fig. 9(d), each of the first wavelength conversion member 31 to the third wavelength conversion member 33 may have a fan-like shape. In the example of Fig. 9(d), the first wavelength conversion member 31 to the third wavelength conversion member 33 have approximately the same area and a central angle of approximately 120 degrees. The first wavelength conversion member 31 to the third wavelength conversion member 33 are adjacent to each other with their centers aligned. A structure including such first wavelength conversion member 31 to the third wavelength conversion member 33 has a circular shape. In other words, the first wavelength conversion member 31 to the third wavelength conversion member 33 have a shape obtained by dividing a circle into three equal parts in the circumferential direction.

[0098] As shown in Fig. 9(e) , the areas of the first wavelength conversion member 31 to the third wavelength conversion member 33 may be different. For example, the area of ​​the second wavelength conversion member 32 that emits fluorescence L1 of the second color (here, green) may be larger than the areas of both the first wavelength conversion member 31 and the third wavelength conversion member 33. In the example of Fig. 9(e) , the second wavelength conversion member 32 has a semicircular shape, and the first wavelength conversion member 31 and the third wavelength conversion member 33 have fan-like shapes with a central angle of approximately 90 degrees. In the example of Fig. 9(e) , the structure including the first wavelength conversion member 31 to the third wavelength conversion member 33 also has a circular shape.

[0099] As shown in FIG. 9( f ), the multiple wavelength conversion members 3 may include a first wavelength conversion member 31 and a second wavelength conversion member 32. The first wavelength conversion member 31 includes, for example, a phosphor made up of a mixture of multiple types of phosphors. The first wavelength conversion member 31 emits fluorescence L1 at a first color temperature that corresponds to the characteristics and mixing ratio of the multiple types of phosphors. For example, 2650 Kelvin (K) is applied to the first color temperature. The second wavelength conversion member 32 also includes, for example, a phosphor made up of a mixture of multiple types of phosphors. The second wavelength conversion member 32 emits fluorescence L1 at a second color temperature that corresponds to the characteristics and mixing ratio of the multiple types of phosphors. For example, 6500 K is applied to the second color temperature. Note that various color temperatures, such as 3000 K, 4000 K, or 5000 K, may be applied to the first or second color temperature.

[0100] 9( f), the first wavelength conversion member 31 and the second wavelength conversion member 32 have a rectangular shape and are arranged in contact with each other in the short side direction (here, the X direction). The structure including the first wavelength conversion member 31 and the second wavelength conversion member 32 has a rectangular shape.

[0101] The plurality of light sources 2 for this structure only need to be a first light source 21 corresponding to the first wavelength conversion member 31 and a second light source 22 corresponding to the second wavelength conversion member 32. In other words, the third light source 23 is not required.

[0102] <2-2. First Aspect> Fig. 10 is a diagram schematically illustrating a first aspect of the configuration of the lighting device 1A according to the second embodiment. In the first aspect of the second embodiment, a plurality of wavelength separation filters 4 are positioned in one-to-one correspondence with a plurality of wavelength conversion members 3. In the example of Fig. 10, the plurality of wavelength separation filters 4 are a first wavelength separation filter 41, a second wavelength separation filter 42, and a third wavelength separation filter 43, which correspond respectively to a first wavelength conversion member 31, a second wavelength conversion member 32, and a third wavelength conversion member 33.

[0103] Each of the first wavelength separation filter 41 to the third wavelength separation filter 43 may be, for example, a dichroic prism, and specifically may include a dielectric multilayer film 401, a first prism 402, and a second prism 403.

[0104] In the example of Figure 10, the first light source 21, the first wavelength separation filter 41, and the first wavelength conversion member 31 are arranged in a first direction (here, the X direction), the second light source 22, the second wavelength separation filter 42, and the second wavelength conversion member 32 are arranged in the X direction, and the third light source 23, the third wavelength separation filter 43, and the third wavelength conversion member 33 are arranged in the X direction.

[0105] 10 , the light-guiding member 5 and the first to third wavelength separation filters 41 to 43 are aligned in the second direction (here, the Z direction). The first to third wavelength separation filters 41 to 43 are aligned in this order in the Z direction, increasing in distance from the light-guiding member 5. That is, the first wavelength separation filter 41 is closest to the light-guiding member 5, and the third wavelength separation filter 43 is farthest from the light-guiding member 5. In other words, the shorter the peak wavelength of the fluorescence L1 emitted by the wavelength conversion member 3, the farther the corresponding wavelength separation filter 4 is positioned from the light-guiding member 5. For example, the third wavelength separation filter 43 corresponding to the third wavelength conversion member 33 that emits the third-color fluorescence L1 with the shortest peak wavelength is positioned farthest from the light-guiding member 5. The light-guiding member 5 and the first to third wavelength separation filters 41 to 43 may be fixed to each other by a fixing agent such as an adhesive.

[0106] The third wavelength separation filter 43 guides the excitation light L0 from the third light source 23 toward the third wavelength conversion member 33, and also guides the third color fluorescence L1 from the third wavelength conversion member 33 toward the second wavelength separation filter 42. Specifically, the third wavelength separation filter 43 transmits the excitation light L0 from the third light source 23 toward the +X side, that is, toward the third wavelength conversion member 33. On the other hand, the third wavelength separation filter 43 reflects the third color fluorescence L1 from the third wavelength conversion member 33 toward the −Z side, that is, toward the second wavelength separation filter 42.

[0107] The second wavelength separation filter 42 guides the excitation light L0 from the second light source 22 to the second wavelength conversion member 32, and also guides both the third color fluorescence L1 from the third wavelength separation filter 43 and the second color fluorescence L1 from the second wavelength conversion member 32 to the first wavelength separation filter 41. Specifically, the second wavelength separation filter 42 transmits the excitation light L0 from the second light source 22 to the +X side, i.e., the second wavelength conversion member 32 side, and transmits the third color fluorescence L1 from the third wavelength separation filter 43 to the -Z side, i.e., the first wavelength separation filter 41 side. The second wavelength separation filter 42 also reflects the second color fluorescence L1 from the second wavelength conversion member 32 to the first wavelength separation filter 41 side.

[0108] The first wavelength separation filter 41 guides the excitation light L0 from the first light source 21 to the first wavelength conversion member 31, and also guides the second-color and third-color fluorescence L1 from the second wavelength separation filter 42 and the first-color fluorescence L1 from the first wavelength conversion member 31 to the light-guiding member 5. Specifically, the first wavelength separation filter 41 transmits the excitation light L0 from the first light source 21 to the +X side, i.e., the first wavelength conversion member 31 side, and transmits the second-color and third-color fluorescence L1 from the second wavelength separation filter 42 to the −Z side, i.e., the light-guiding member 5 side. The first wavelength separation filter 41 also reflects the first-color fluorescence L1 from the first wavelength conversion member 31 toward the light-guiding member 5 side.

[0109] FIG. 11 is a graph showing an example of the spectral transmittance of the first wavelength separation filter 41 to the third wavelength separation filter 43. The example of FIG. 11 shows the spectral transmittance T41 of the dielectric multilayer film 401 of the first wavelength separation filter 41, the spectral transmittance T42 of the dielectric multilayer film 401 of the second wavelength separation filter 42, and the spectral transmittance T43 of the dielectric multilayer film 401 of the third wavelength separation filter 43. The "light source wavelength" shown in FIG. 11 indicates, for example, the excitation peak wavelength of the excitation light L0, and the "first fluorescent wavelength" to "third fluorescent wavelength" indicate, for example, the peak wavelengths of the first color, the second color, and the third color fluorescence L1, respectively. The first fluorescent wavelength is, for example, 610 nm or more and 800 nm or less, a specific example being 650 nm. The second fluorescent wavelength is, for example, 510 nm or more and 590 nm or less, a specific example being 550 nm. The third fluorescent wavelength is, for example, 460 nm or more and 490 nm or less, and a specific example is 480 nm. Note that, for simplicity, the description will be given ignoring the polarization state.

[0110] 11 , the dielectric multilayer films 401 of the first to third wavelength separation filters 41 to 43 may be short-pass dichroic films. That is, the dielectric multilayer film 401 may transmit light with wavelengths shorter than a predetermined cutoff wavelength and reflect light with wavelengths longer than the cutoff wavelength. As a specific example, the cutoff wavelength λc1 of the spectral transmittance T41 is set between the first peak wavelength (i.e., the first fluorescent wavelength) of the first-color fluorescence L1 and the second peak wavelength (i.e., the second fluorescent wavelength) of the second-color fluorescence L1, the cutoff wavelength λc2 of the spectral transmittance T42 is set between the second fluorescent wavelength and the third peak wavelength (i.e., the third fluorescent wavelength) of the third-color fluorescence L1, and the cutoff wavelength λc3 of the spectral transmittance T43 is set between the third fluorescent wavelength and the excitation peak wavelength (i.e., the light source wavelength) of the excitation light L0. The cutoff wavelength λc3 is set to a value greater than 440 nm and less than 460 nm, specifically 450 nm, for example. The dielectric multilayer film 401 of the third wavelength separation filter 43 transmits light in the wavelength range of 400 nm to 440 nm and reflects light in the wavelength range of 460 nm to 800 nm. The cutoff wavelength λc2 is set to a value greater than 490 nm and less than 510 nm, specifically 500 nm, for example. The dielectric multilayer film 401 of the second wavelength separation filter 42 transmits light in the wavelength range of 400 nm to 490 nm and reflects light in the wavelength range of 510 nm to 800 nm, for example. The cutoff wavelength λc1 is set to a value greater than 590 nm and less than 610 nm, specifically 600 nm, for example. The dielectric multilayer film 401 of the first wavelength separation filter 41 transmits light in the wavelength range of, for example, 400 nm or more and 590 nm or less, and reflects light in the wavelength range of 610 nm or more and 800 nm or less.

[0111] 11 , the third wavelength separation filter 43 transmits the excitation light L0 and reflects the third color (blue in this case) fluorescence L1 from the third wavelength conversion member 33. This third color fluorescence L1 is incident on the second wavelength separation filter 42.

[0112] 11 , the second wavelength separation filter 42 transmits the excitation light L0 and the third color fluorescence L1 and reflects the second color (here, green) fluorescence L1 from the second wavelength conversion member 32. Therefore, the second color fluorescence L1 and the third color fluorescence L1 mix together and enter the first wavelength separation filter 41. In other words, the second wavelength separation filter 42 also functions as a combining element that combines the second color fluorescence L1 and the third color fluorescence L1 and guides the combined fluorescence L1 to the first wavelength separation filter 41.

[0113] 11 , the first wavelength separation filter 41 transmits the excitation light L0, the second color fluorescence L1, and the third color fluorescence L1, and reflects the first color (red in this case) fluorescence L1 from the first wavelength conversion member 31. Therefore, the first to third color fluorescence L1 mix and enter the end surface 5b of the light-guiding member 5. In other words, the first wavelength separation filter 41 also functions as a combining element that combines the first to third color fluorescence L1 and guides the combined fluorescence L1 to the light-guiding member 5.

[0114] The fluorescence L1 of the first to third colors travels from the end surface 5b of the light-guiding member 5 toward the exit surface 5c inside the light-guiding member 5. Specifically, the fluorescence L1 of the first to third colors travels inside the light-guiding member 5 while being repeatedly reflected by the cylindrical surface 5a of the light-guiding member 5. This makes it possible to improve the uniformity of the fluorescence L1 emitted from the exit surface 5c of the light-guiding member 5.

[0115] Moreover, according to the first aspect of the second embodiment, the first wavelength separation filter 41, the second wavelength separation filter 42, and the third wavelength separation filter 43 are positioned corresponding to the first wavelength conversion member 31, the second wavelength conversion member 32, and the third wavelength conversion member 33, respectively. This allows the areas of the first wavelength conversion member 31 to the third wavelength conversion member 33 to be increased. This allows the areas of the irradiation regions of the excitation light L0 incident on each of the first wavelength conversion member 31 to the third wavelength conversion member 33 to be increased. Therefore, even if the power density of the excitation light L0 in the irradiation regions is reduced, each of the first wavelength conversion member 31 to the third wavelength conversion member 33 can emit the fluorescence L1 with a sufficient amount of light. Furthermore, reducing the power density of the excitation light L0 can reduce the temperature rise occurring in each of the first wavelength conversion member 31 to the third wavelength conversion member 33. This reduces the degree of thermal degradation of the first wavelength conversion member 31 to the third wavelength conversion member 33. That is, it is possible to reduce thermal deterioration of the first wavelength conversion member 31 to the third wavelength conversion member 33 while ensuring the light amount of the fluorescent light L1.

[0116] 10, the shorter the peak wavelength of the fluorescence L1 emitted by the corresponding wavelength conversion member 3, the farther the wavelength separation filter 4 is located from the light-guiding member 5. As can be seen from Fig. 11, a short-pass dichroic film can be used as the dielectric multilayer film 401 of the wavelength separation filter 4. The optical design of such a dielectric multilayer film 401 with one cutoff wavelength is relatively easy.

[0117] 11 , the first to third wavelength conversion members 31 to 33 may be located on the same side of the first to third wavelength separation filters 41 to 43. In the example of Fig. 11 , the first wavelength conversion member 31 is located on the +X side (corresponding to the first side) of the first wavelength separation filter 41, the second wavelength conversion member 32 is located on the +X side of the second wavelength separation filter 42, and the third wavelength conversion member 33 is located on the +X side of the third wavelength separation filter 43. For this reason, as shown in Fig. 11 , the first to third wavelength conversion members 31 to 33 can easily be attached to a common cooling member 75.

[0118] 11 , the cooling member 75 has a plate-like shape and is positioned with its thickness direction along the X direction. The cooling member 75 is positioned on the +X side with respect to the wavelength conversion member 3, that is, on the opposite side from the wavelength separation filter 4. The cooling member 75 also functions as a support member that supports all of the first wavelength conversion member 31 to the third wavelength conversion member 33.

[0119] The cooling member 75 has a thermal conductivity higher than that of all of the first wavelength conversion member 31, the second wavelength conversion member 32, and the third wavelength conversion member 33. For example, a metal material with high thermal conductivity is used as the material for the cooling member 75. Examples of such metal materials include copper (Cu), aluminum (Al), magnesium (Mg), gold (Au), silver (Ag), iron (Fe), chromium (Cr), cobalt (Co), beryllium (Be), molybdenum (Mo), tungsten (W), and alloys. Such a cooling member 75 can function as a heat sink that cools the first wavelength conversion member 31 to the third wavelength conversion member 33. This can reduce the degree of thermal degradation of the wavelength conversion member 3.

[0120] The first to third wavelength conversion members 31 to 33 may be directly bonded to the surface 75a on the -X side of the cooling member 75. For example, by forming phosphor pellets on the surface 75a of the cooling member by heat molding or the like, the surfaces 3a of the first to third wavelength conversion members 31 to 33 can be directly bonded to the surface 75a of the cooling member 75. In this way, if the cooling member 75 is directly bonded to the wavelength conversion member 3, the heat of the wavelength conversion member 3 can be transferred to the cooling member 75 more quickly. This further reduces the degree to which the wavelength conversion member 3 is deteriorated by heat.

[0121] Furthermore, in the first aspect, the first wavelength conversion member 31 to the third wavelength conversion member 33 are attached to the common cooling member 75, and therefore the lighting device 1A can be easily assembled.

[0122] 12 is a diagram schematically illustrating a second aspect of the optical system of the illumination device 1A according to the second embodiment. The illumination device 1A according to the second aspect of the second embodiment differs from the illumination device 1A in FIG. 10 in the positions of the light source 2, the wavelength separation filter 4, and the wavelength conversion member 3.

[0123] 12 , the arrangement order of the light source 2, the wavelength separation filter 4, and the wavelength conversion member 3 alternates as they move away from the light-guiding member 5. Specifically, in the example of FIG. 12 , the first light source 21, the first wavelength separation filter 41, and the first wavelength conversion member 31 are located in this order from the −X side to the +X side. On the other hand, the second light source 22, the second wavelength separation filter 42, and the second wavelength conversion member 32 are located in this order from the +X side to the −X side. In other words, the arrangement order of the second light source 22, the second wavelength separation filter 42, and the second wavelength conversion member 32 is reversed from that of the first light source 21, the first wavelength separation filter 41, and the first wavelength conversion member 31. The third light source 23, the third wavelength separation filter 43, and the third wavelength conversion member 33 are located in this order from the −X side to the +X side.

[0124] 12 , the dielectric multilayer film 401 of the first wavelength separation filter 41 and the second wavelength separation filter 42 extends from the −X side and the −Z side to the +X side and the +Z side, and the dielectric multilayer film 401 of the second wavelength separation filter 42 extends from the −X side and the +Z side to the +X side and the −Z side. This allows the dielectric multilayer film 401 of the second wavelength separation filter 42 to reflect the second color fluorescence L1 from the second wavelength conversion member 32 toward the −Z side, i.e., toward the first wavelength separation filter 41.

[0125] As described above, according to the second aspect, the second wavelength conversion member 32 is located on the opposite side of the wavelength separation filter 42 in the X direction from the first wavelength conversion member 31 and the third wavelength conversion member 33. In other words, unlike the first wavelength conversion member 31 and the third wavelength conversion member 33, the second wavelength conversion member 32 is located on the −X side (corresponding to the second side) of the second wavelength separation filter 42. This makes it possible to widen the gap between adjacent pairs of the multiple wavelength conversion members 3. The first wavelength conversion member 31 to the third wavelength conversion member 33 generate heat and function as a heat source, and the wide gap between the wavelength conversion members 3 allows each wavelength conversion member 3 to be cooled more effectively.

[0126] 13 is a diagram schematically illustrating a third aspect of the optical system of the illumination device 1A according to the second embodiment. The illumination device 1A according to the third aspect of the second embodiment differs from the illumination device 1A in FIG. 12 in the position of the third wavelength conversion member 33 and the characteristics of the third wavelength separation filter 43.

[0127] In the third mode of the second embodiment, the third wavelength conversion member 33 faces the third wavelength separation filter 43 in the Z direction and is located on the +Z side of the third wavelength separation filter 43. That is, the third wavelength conversion member 33 is located on the +Z side of the third wavelength separation filter 43, which is farthest from the light-guiding member 5 in the Z direction. The third wavelength conversion member 33 is located with its thickness direction aligned with the Z direction.

[0128] The third wavelength separation filter 43 reflects the excitation light L0 from the third light source 23 toward the +Z side. As a result, the excitation light L0 travels toward the third wavelength conversion member 33 and is incident on the third wavelength conversion member 33. The third color fluorescence L1 emitted by the third wavelength conversion member 33 travels toward the third wavelength separation filter 43 and is incident on the third wavelength separation filter 43. The third wavelength separation filter 43 transmits the third color fluorescence L1 toward the -Z side. As a result, the third color fluorescence L1 travels toward the second wavelength separation filter 42.

[0129] 14 is a diagram schematically illustrating a fourth aspect of the optical system of the illumination device 1A according to the second embodiment. The illumination device 1A according to the fourth aspect of the second embodiment differs from the illumination device 1A in FIG. 10 in the structure of the wavelength separation filter 4.

[0130] In a fourth aspect of the second embodiment, the wavelength separation filter 4 includes three dielectric multilayer films 401: a first transparent member 410, a second transparent member 412, a third transparent member 423, and a fourth transparent member 430. The three dielectric multilayer films 401 correspond to the first wavelength conversion member 31 to the third wavelength conversion member 33, respectively. Hereinafter, the dielectric multilayer film 401 corresponding to the first wavelength conversion member 31 will be referred to as the first dielectric multilayer film 411, the dielectric multilayer film 401 corresponding to the second wavelength conversion member 32 will be referred to as the second dielectric multilayer film 421, and the dielectric multilayer film 401 corresponding to the third wavelength conversion member 33 will be referred to as the third dielectric multilayer film 431.

[0131] The spectral transmittance of the first dielectric multilayer film 411 is, for example, the same as the spectral transmittance T41 in Fig. 11, the spectral transmittance of the second dielectric multilayer film 421 is, for example, the same as the spectral transmittance T42 in Fig. 11, and the spectral transmittance of the third dielectric multilayer film 431 is, for example, the same as the spectral transmittance T43 in Fig. 11. In other words, the first dielectric multilayer film 411 to the third dielectric multilayer film 431 substantially realize the functions of the first wavelength separation filter 41 to the third wavelength separation filter 43 in Fig. 10, respectively.

[0132] 14 , first dielectric multilayer film 411 is located between first transparent member 410 and second transparent member 412, second dielectric multilayer film 421 is located between second transparent member 412 and third transparent member 423, and third dielectric multilayer film 431 is located between third transparent member 423 and fourth transparent member 430. The material of first transparent member 410, second transparent member 412, third transparent member 423, and fourth transparent member 430 can be, for example, at least one of glass such as optical glass and resin such as acrylic resin.

[0133] The first transparent member 410 has a side surface 410a, an inclined surface 410b, and an end surface 410c. The end surface 410c faces the end surface 5b of the light-guiding member 5 in the Z direction and may be in contact with the end surface 5b. The end surface 410c may be approximately parallel to the end surface 5b. The inclined surface 410b of the first transparent member 410 is the surface opposite the end surface 410c and is inclined at the same degree as the first dielectric multilayer film 411. The side surface 410a is a side surface that connects the inclined surface 410b and the end surface 410c of the first transparent member 410. The first transparent member 410 may be, for example, a prism having a triangular prism shape in which both end surfaces in the Y direction are right triangles.

[0134] The second transparent member 412 has a side surface 412a, an inclined surface 412b, and an inclined surface 412c. The inclined surface 412c faces the inclined surface 410b of the first transparent member 410 and is substantially parallel to the inclined surface 410b. A first dielectric multilayer film 411 is located between the inclined surface 410b of the first transparent member 410 and the inclined surface 412c of the second transparent member 412. The first dielectric multilayer film 411 may be formed on one of the inclined surfaces 410b and 412c, and a fixing agent such as a transparent adhesive may be located between the other of the inclined surfaces 410b and 412c and the first dielectric multilayer film 411. The first dielectric multilayer film 411 is supported by the first transparent member 410 and the second transparent member 412.

[0135] Inclined surface 412b of second transparent member 412 is the surface opposite to inclined surface 412c and is approximately parallel to inclined surface 412c. Side surface 412a is a side surface that connects the periphery of inclined surface 412b with the periphery of inclined surface 412c. Second transparent member 412 has, for example, a quadrangular prism shape in which both end faces in the Y direction are parallelograms.

[0136] Third transparent member 423 has side surface 423a and inclined surface 423b and inclined surface 423c. The shape of third transparent member 423 is, for example, the same as the shape of second transparent member 412. Second dielectric multilayer film 421 is located between inclined surface 412b of second transparent member 412 and inclined surface 423c of third transparent member 423. Second dielectric multilayer film 421 may be formed on one of inclined surface 412b and inclined surface 423c, and a fixing agent such as an adhesive may be located between the other of inclined surface 412b and inclined surface 423c and second dielectric multilayer film 421. Second dielectric multilayer film 421 is supported by second transparent member 412 and third transparent member 423.

[0137] The fourth transparent member 430 has a side surface 430a, an end surface 430b, and an inclined surface 430c. The shape of the fourth transparent member 430 is, for example, the same as the shape of the first transparent member 410, and is positioned in a state inverted in the Z direction relative to the first transparent member 410. A third dielectric multilayer film 431 is positioned between the inclined surface 423b of the third transparent member 423 and the inclined surface 430c of the fourth transparent member 430. The third dielectric multilayer film 431 may be formed on one of the inclined surfaces 423b and 430c, and a fixing agent such as an adhesive may be positioned between the other of the inclined surfaces 423b and 430c and the third dielectric multilayer film 431. The third dielectric multilayer film 431 is supported by the third transparent member 423 and the fourth transparent member 430.

[0138] As described above, the second transparent member 412 is located between the first dielectric multilayer film 411 and the second dielectric multilayer film 421. Because the second transparent member 412 is a single piece, there is no boundary (adhesive surface) between different members in the region between the inclined surfaces 412b and 412c. This reduces loss of the fluorescence L1, allowing the lighting device 1A to emit the fluorescence L1 into the illumination space S1 with higher efficiency. Because the third transparent member 423 between the second dielectric multilayer film 421 and the third dielectric multilayer film 431 is also a single piece, loss of the fluorescence L1 can be reduced.

[0139] 11 , the first dielectric multilayer film 411 can be said to be the dielectric multilayer film 401 of the first wavelength separation filter 41. Like the first dielectric multilayer film 411, the second dielectric multilayer film 421 is the dielectric multilayer film 401 of the second wavelength separation filter 42, and the third dielectric multilayer film 431 is the dielectric multilayer film 401 of the third wavelength separation filter 43. Therefore, in the fourth aspect of the second embodiment, it can be said that a second transparent member 412 formed from a single member is located between the dielectric multilayer film 401 of the first wavelength separation filter 41 and the second wavelength separation filter 42, and a third transparent member 423 formed from a single member is located between the dielectric multilayer film 401 of the second wavelength separation filter 42 and the third wavelength separation filter 43.

[0140] 2-6. Fifth Aspect> Fig. 15 is a diagram schematically illustrating a fifth aspect of the optical system of the illumination device 1A according to the second embodiment. The illumination device 1A according to the fifth aspect of the second embodiment differs from the illumination device 1A of Fig. 14 in the positions of the light source 2 and the wavelength conversion member 3. In the example of Fig. 15, the second wavelength conversion member 32 is located on the opposite side of the wavelength separation filter 4 in the X direction from the first wavelength conversion member 31 and the third wavelength conversion member 33. The second light source 22 is located on the opposite side of the wavelength separation filter 4 in the X direction from the first light source 21 and the third light source 23.

[0141] Therefore, the inclination of second dielectric multilayer film 421 is opposite to the inclination of first dielectric multilayer film 411 and third dielectric multilayer film 431. Since inclined surface 412b of second transparent member 412 and inclined surface 423c of third transparent member 423 are substantially parallel to second dielectric multilayer film 421, the inclination of inclined surface 412b of second transparent member 412 is opposite to the inclination of inclined surface 412c, and the inclination of inclined surface 423c of third transparent member 423 is opposite to the inclination of inclined surface 423b. Therefore, second transparent member 412 has, for example, a triangular prism shape in which both end faces in the Y direction are right-angled isosceles triangles, and third transparent member 423 has, for example, the same shape.

[0142] In the fifth aspect of the second embodiment, the loss of fluorescence L1 can also be reduced because the second transparent member 412, which is formed from a single member, is located between the first dielectric multilayer film 411 and the second dielectric multilayer film 421. Furthermore, the third transparent member 423, which is formed from a single member, is located between the second dielectric multilayer film 421 and the third dielectric multilayer film 431, which can further reduce the loss of fluorescence L1.

[0143] 2-7. Sixth Aspect FIG. 16 is a diagram schematically illustrating a sixth aspect of the optical system of the illumination device 1A according to the second embodiment. The illumination device 1A according to the sixth aspect of the second embodiment differs from the illumination device 1A of FIG. 10 in the configuration of the wavelength separation filter 4. In the example of FIG. 16, each of the first wavelength separation filter 41 to the third wavelength separation filter 43 includes a dielectric multilayer film 401 and a plate-shaped transparent substrate 404. This structure allows for a reduction in the manufacturing cost of each of the first wavelength separation filter 41 to the third wavelength separation filter 43.

[0144] A condensing lens may be located between the first wavelength separation filter 41 and the first wavelength conversion member 31. The fluorescence L1 of the first color from the first wavelength conversion member 31 enters the first wavelength separation filter 41 through the condensing lens. This allows more of the fluorescence L1 from the first wavelength conversion member 31 to enter the first wavelength separation filter 41. Condenser lenses may also be located between the second wavelength separation filter 42 and the second wavelength conversion member 32, and between the third wavelength separation filter 43 and the third wavelength conversion member 33.

[0145] 17 is a diagram schematically illustrating a seventh aspect of the optical system of the illumination device 1A according to the second embodiment. The illumination device 1A according to the seventh aspect of the second embodiment differs from the illumination device 1A in FIG. 10 in the positions of the light source 2, the wavelength conversion member 3, and the wavelength separation filter 4.

[0146] As shown in FIG. 17 , the second wavelength separation filter 42 may be aligned with the first wavelength separation filter 41 in the X direction. In the example of FIG. 17 , the second wavelength separation filter 42 is located on the +X side of the first wavelength separation filter 41. Also, as shown in FIG. 17 , the third wavelength separation filter 43 may be aligned with the second wavelength separation filter 42 in the Z direction. In the example of FIG. 17 , the third wavelength separation filter 43 is located on the −Z side of the second wavelength separation filter 42, that is, on the light-guiding member 5 side. Therefore, the third wavelength separation filter 43 is adjacent to the light-guiding member 5 in the X direction. In the example of FIG. 17 , the third wavelength separation filter 43 is located on the +X side of the light-guiding member 5. The light-guiding member 5 and the first to third wavelength separation filters 41 to 43 may be appropriately fixed with a fixing agent such as a transparent adhesive.

[0147] 17 , the third light source 23 may be aligned with the third wavelength separation filter 43 in the X direction, and the third wavelength conversion member 33 may be aligned with the third wavelength separation filter 43 in the Z direction. In the example of Fig. 17 , the third light source 23 is located on the +X side of the third wavelength separation filter 43, that is, on the opposite side from the light-guiding member 5, and the third wavelength conversion member 33 is located on the -Z side of the third wavelength separation filter 43, that is, on the opposite side from the second wavelength separation filter 42.

[0148] The third wavelength separation filter 43 reflects the excitation light L0 from the third light source 23 toward the −Z side, that is, toward the third wavelength conversion member 33. On the other hand, the third wavelength separation filter 43 transmits the third color fluorescence L1 from the third wavelength conversion member 33 toward the +X side, that is, toward the second wavelength separation filter 42.

[0149] 17 , the second light source 22 may be aligned with the second wavelength separation filter 42 in the Z direction, and the second wavelength conversion member 32 may be aligned with the second wavelength separation filter 42 in the X direction. In the example of Fig. 17 , the second light source 22 is located on the +Z side of the second wavelength separation filter 42, i.e., on the opposite side from the first wavelength separation filter 41, and the second wavelength conversion member 32 is located on the +X side of the second wavelength separation filter 42, i.e., on the opposite side from the first wavelength separation filter 41.

[0150] The second wavelength separation filter 42 reflects the excitation light L0 from the second light source 22 toward the +X side, that is, toward the second wavelength conversion member 32. It also reflects the third color fluorescence L1 from the third wavelength separation filter 43 toward the −X side, that is, toward the first wavelength separation filter 41. On the other hand, the second wavelength separation filter 42 transmits the second color fluorescence L1 from the second wavelength conversion member 32 toward the −X side, that is, toward the first wavelength separation filter 41.

[0151] 17 , the first light source 21 may be aligned with the first wavelength separation filter 41 in the X direction, and the first wavelength conversion member 31 may be aligned with the first wavelength separation filter 41 in the Z direction. In the example of Fig. 17 , the first light source 21 is located on the -X side of the first wavelength separation filter 41, that is, on the opposite side from the second wavelength separation filter 42, and the first wavelength conversion member 31 is located on the +Z side of the first wavelength separation filter 41, that is, on the opposite side from the light-guiding member 5.

[0152] The first wavelength separation filter 41 reflects the excitation light L0 from the first light source 21 toward the +Z side, that is, toward the first wavelength conversion member 31. Also, it reflects the second-color and third-color fluorescence L1 from the second wavelength separation filter 42 toward the −Z side, that is, toward the light-guiding member 5. On the other hand, the first wavelength separation filter 41 transmits the first-color fluorescence L1 from the first wavelength conversion member 31 toward the −Z side, that is, toward the light-guiding member 5.

[0153] As described above, in the example of FIG. 17, the path of the third color fluorescence L1 passing through the third wavelength separation filter 43 and the first wavelength separation filter 41 in this order is formed in a U-shape.

[0154] The second wavelength separation filter 42 is adjacent to the first wavelength separation filter 41 in the X direction. This allows the size of the lighting device 1A to be reduced in the Z direction. When the lighting device 1A is installed in an attic space, the lighting device 1A is installed with the Z direction aligned with the vertical direction. However, the height of the attic space may be low. Specifically, the height of the attic space may be approximately 10 cm. As described above, if the size of the lighting device 1A in the Z direction can be reduced, the lighting device 1A can be easily installed in a low-height attic space.

[0155] Furthermore, in the above example, the third wavelength separation filter 43 is located on the −Z side relative to the second wavelength separation filter 42. This allows the size of the lighting device 1A in the Z direction to be further reduced. This makes it easier to install the lighting device 1A in a low-height space above the ceiling.

[0156] 17 , the shorter the peak wavelength of the fluorescence L1, the farther the wavelength separation filter 4 is from the light-guiding member 5 in the U-shaped path of the fluorescence L1. For example, the third wavelength separation filter 43 is located farthest from the light-guiding member 5 in the U-shaped path of the third-color fluorescence L1. Accordingly, the first wavelength separation filter 41, the second wavelength separation filter 42, and the third wavelength separation filter can be made of a dielectric multilayer film 401 having a simple spectral transmittance with a single cutoff wavelength. However, as can be understood from the above explanation, a long-pass dichroic film that reflects light with short wavelengths and transmits light with long wavelengths is used for the dielectric multilayer film 401.

[0157] 18 is a diagram schematically illustrating an eighth aspect of the optical system of the illumination device 1A according to the second embodiment. The illumination device 1A according to the eighth aspect of the second embodiment differs from the illumination device 1A of FIG. 10 in the positions of the light source 2, the wavelength conversion member 3, and the wavelength separation filter 4, and in the presence or absence of a combining element 45.

[0158] The fluorescence L1 from the first wavelength separation filter 41 to the third wavelength separation filter 43 enters the combining element 45 from different directions. That is, the first color fluorescence L1 from the first wavelength separation filter 41 enters the combining element 45 without passing through either the second wavelength separation filter 42 or the third wavelength separation filter 43. The second and third color fluorescence L1 also enter the combining element 45. The combining element 45 is an optical element that combines the fluorescence L1 from the first wavelength separation filter 41, the second wavelength separation filter 42, and the third wavelength separation filter 43 and guides it to the end face 5b of the light-guiding member 5. The combining element 45 is, for example, a cross prism. The combining element 45 is aligned with the light-guiding member 5 in the Z direction and is located on the +Z side of the light-guiding member 5.

[0159] 18 , the first wavelength separation filter 41 may be aligned with the combining element 45 in the X direction, and in the example of FIG. 18 , the first wavelength separation filter 41 is located on the +X side of the combining element 45. The second wavelength separation filter 42 may be aligned with the combining element 45 in the Z direction, and in the example of FIG. 18 , the second wavelength separation filter 42 is located on the +Z side of the combining element 45, that is, on the opposite side from the light-guiding member 5. The third wavelength separation filter 43 may be aligned with the combining element 45 in the X direction, and in the example of FIG. 18 , the third wavelength separation filter 43 is located on the +Z side of the combining element 45, that is, on the opposite side from the first wavelength separation filter 41. As described above, multiple wavelength separation filters 4 and light-guiding members 5 may be arranged to surround the periphery of the combining element 45.

[0160] 18, the first light source 21 may be aligned with the first wavelength separation filter 41 in the Z direction, and the first wavelength conversion member 31 may be aligned with the first wavelength separation filter 41 in the X direction. In the example of Fig. 18, the first light source 21 is located on the -Z side of the first wavelength separation filter 41, and the first wavelength conversion member 31 is located on the +X side of the first wavelength separation filter 41, that is, on the opposite side from the combining element 45.

[0161] The first wavelength separation filter 41 reflects the excitation light L0 from the first light source 21 toward the +X side, that is, toward the first wavelength conversion member 31. On the other hand, the first wavelength separation filter 41 transmits the first color fluorescence L1 from the first wavelength conversion member 31 toward the −X side, that is, toward the combining element 45.

[0162] 18 , the second light source 22 may be aligned with the second wavelength separation filter 42 in the X direction, and the second wavelength conversion member 32 may be aligned with the second wavelength separation filter 42 in the Z direction. In the example of Fig. 18 , the second light source 22 is located on the +X side of the second wavelength separation filter 42, and the second wavelength conversion member 32 is located on the +Z side of the second wavelength separation filter 42, that is, on the opposite side from the combining element 45.

[0163] The second wavelength separation filter 42 reflects the excitation light L0 from the second light source 22 toward the +Z side, that is, toward the second wavelength conversion member 32. On the other hand, the second wavelength separation filter 42 transmits the second color fluorescence L1 from the second wavelength conversion member 32 toward the −Z side, that is, toward the combining element 45.

[0164] 18 , the third light source 23 may be aligned with the third wavelength separation filter 43 in the Z direction, and the third wavelength conversion member 33 may be aligned with the third wavelength separation filter 43 in the X direction. In the example of Fig. 18 , the third light source 23 is located on the +Z side of the third wavelength separation filter 43, and the third wavelength conversion member 33 is located on the -X side of the third wavelength separation filter 43, that is, on the opposite side from the combining element 45.

[0165] The third wavelength separation filter 43 reflects the excitation light L0 from the third light source 23 toward the −X side, that is, toward the third wavelength conversion member 33. On the other hand, the third wavelength separation filter 43 transmits the third color fluorescence L1 from the third wavelength conversion member 33 toward the +X side, that is, toward the combining element 45.

[0166] As described above, the first color, second color, and third color fluorescence L1 are incident from three directions onto the confluence element 45. The confluence element 45 guides the first color, second color, and third color fluorescence L1 to the −Z side, i.e., the light-guiding member 5 side.

[0167] As shown in FIG. 18, the combining element 45 may include a first dielectric multilayer film 451 , a second dielectric multilayer film 452 , and a first prism 453 to a fourth prism 456 .

[0168] The first dielectric multilayer film 451 and the second dielectric multilayer film 452 intersect in a cross shape. For example, the first dielectric multilayer film 451 is positioned such that its surface extends from the −X side and −Z side to the +X side and +Z side, and the second dielectric multilayer film 452 is positioned such that its surface extends from the −X side and +Z side to the +X side and −Z side. The first dielectric multilayer film 451 reflects the first-color fluorescence L1 from the first wavelength conversion member 31 toward the −Z side, and transmits the second-color fluorescence L1 from the second wavelength conversion member 32 and the third-color fluorescence L1 from the third wavelength conversion member 33. The second dielectric multilayer film 452 reflects the third-color fluorescence L1 from the third wavelength conversion member 33 toward the −Z side, and transmits the first-color fluorescence L1 from the first wavelength conversion member 31 and the second-color fluorescence L1 from the second wavelength conversion member 32.

[0169] According to this combining element 45, the first color fluorescence L1 is reflected toward the −Z side by the combining element 45, the second color fluorescence L1 is transmitted through the combining element 45 toward the −Z side, and the third color fluorescence L1 is reflected toward the −Z side by the combining element 45. Therefore, the first color, second color, and third color fluorescence L1 combined by the combining element 45 are incident on the end surface 5b of the light-guiding member 5.

[0170] 18 , the first prism 453 to the fourth prism 456 have, for example, triangular prism shapes in which both end faces in the Y direction are right-angled isosceles triangles, and are positioned such that their vertices approximately coincide. The first prism 453 is positioned on the −Z side of the vertex, the second prism 454 is positioned on the −X side, the third prism 455 is positioned on the +Z side, and the fourth prism 456 is positioned on the +X side. The first dielectric multilayer film 451 is positioned between the first prism 453 and the second prism 454 and between the third prism 455 and the fourth prism 456, and the second dielectric multilayer film 452 is positioned between the second prism 454 and the third prism 455 and between the first prism 453 and the fourth prism 456.

[0171] According to the eighth aspect of the second embodiment, the first wavelength separation filter 41 and the third wavelength separation filter 43 are aligned in the X direction, which allows the size of the illumination device 1A in the Z direction to be reduced.

[0172] Furthermore, each of the first to third wavelength separation filters 41 to 43 only needs to reflect the excitation light L0 and does not need to reflect the fluorescence L1. In other words, each of the first to third wavelength separation filters 41 to 43 may be capable of transmitting the first to third color fluorescence L1. Therefore, the cutoff frequencies of the dielectric multilayer films 401 of the first to third wavelength separation filters 41 to 43 only need to be located between the excitation peak wavelength of the excitation light L0 and the third peak wavelength of the third color fluorescence L1. In other words, filters with the same specifications can be used for the first to third wavelength separation filters 41 to 43. This facilitates component management.

[0173] 17 , an air gap may be located between the first prism 402 and the second prism 403 in at least one of the first wavelength separation filter 41 to the third wavelength separation filter 43. As a specific example, the dielectric multilayer film 401 may be formed on the first prism 402, and an air gap may be located between the dielectric multilayer film 401 and the second prism 403.

[0174] This makes it possible to reduce the wavelength dependency of the spectral transmittance of the wavelength separation filter 4 .

[0175] 19 is a diagram schematically illustrating an example of an optical system of an illumination device 1B according to a third embodiment. The illumination device 1B differs from the illumination device 1A of FIG. 8 in the number of light sources 2 and the presence or absence of a drive unit 25. As shown in FIG. 19, the illumination device 1B may be provided with a single light source 2.

[0176] The driving unit 25 displaces the light source 2 to change the irradiation area of ​​the excitation light L0 in the wavelength conversion member 3. For example, the driving unit 25 may move the light source 2 along the Z direction. By moving the light source 2 along the Z direction, the irradiation area of ​​the wavelength conversion member 3 with the excitation light L0 can be moved along the X direction.

[0177] The driving unit 25 may include, for example, a motor as a driving source that generates a driving force to move the light source 2. The driving unit 25 may further include a power transmission mechanism such as a ball screw mechanism that transmits the driving force from the driving source to the light source 2.

[0178] 20A to 20F are diagrams schematically illustrating examples of the arrangement of wavelength conversion members 3 and irradiation regions R1 of excitation light L0. The arrangement patterns of wavelength conversion members 3 in Fig. 20A to Fig. 20F are the same as the arrangement patterns in Fig. 9A to Fig. 9F, respectively.

[0179] In FIG. 20( a), the irradiation region R1 of the excitation light L0 is shown as a rectangle. The shape of the irradiation region R1 can be determined, for example, by placing one or more lenses between the light source 2 and the wavelength separation filter 4 and by the optical design of the lenses. In FIG. 20( a), the irradiation region R1 spans the first wavelength conversion member 31 and the second wavelength conversion member 32 but is not located within the third wavelength conversion member 33. In this case, the illumination device 1B can emit fluorescence L1 in which the first color and the second color are mixed at a mixing ratio corresponding to the area ratio of the first wavelength conversion member 31 and the second wavelength conversion member 32 within the irradiation region R1. By moving the irradiation region R1 along the X direction, the area of ​​each wavelength conversion member 3 within the irradiation region R1 changes, thereby changing the color of the fluorescence L1. Note that in the example of FIG. 20( a), the direction of movement of the irradiation region R1 is schematically indicated by a double-headed arrow.

[0180] The control unit 8 controls the light source 2 and the drive unit 25. For example, when the control unit 8 outputs a control signal corresponding to a target value for the hue of the fluorescence L1 to the drive unit 25, the drive unit 25 moves the light source 2 along the Z direction to a position based on the control signal. This causes the excitation light L0 from the light source 2 to be incident on the wavelength conversion member 3, in an irradiation region R1 corresponding to the target value for the hue of the fluorescence L1. Therefore, the lighting device 1B can emit fluorescence L1 whose hue is close to the target value into the illumination space S1.

[0181] 20(b) and 20(c), the first wavelength conversion member 31 to the third wavelength conversion member 33 are positioned two-dimensionally on the XY plane. Therefore, the driving unit 25 may move the light source 2 two-dimensionally. For example, the driving unit 25 may move the light source 2 in the Y direction and the Z direction, thereby moving the irradiation region R1 of the wavelength conversion member 3 in the X direction and the Y direction. Note that in the examples of FIGS. 20(b) and 20(c), the movement direction of the irradiation region R1 is also schematically indicated by a double-headed arrow.

[0182] The driving unit 25 may include, for example, a first motor as an example of a driving source for the Y direction and a second motor as an example of a driving source for the Z direction. The driving unit 25 may further include a power transmission mechanism for the Y direction, such as a ball screw mechanism, that transmits the driving force of the first motor to the light source 2, and a power transmission mechanism for the X direction, such as a ball screw mechanism, that transmits the driving force of the second motor to the light source 2.

[0183] In the examples of Figures 20(d) and 20(e), the irradiation region R1 is shown as a circle. The diameter of the irradiation region R1 is smaller than the diameter of the circle of the structure including the first wavelength conversion member 31 to the third wavelength conversion member 33. The center of the irradiation region R1 is shifted from the center Q1 of the circle. In the examples of Figures 20(d) and 20(e), the irradiation region R1 spans the first wavelength conversion member 31 to the third wavelength conversion member 33. Therefore, the lighting device 1B can emit, into the illumination space S1, fluorescence L1 in which the first color, the second color, and the third color are mixed at a mixing ratio corresponding to the area ratio of the first wavelength conversion member 31 to the third wavelength conversion member 33 within the irradiation region R1.

[0184] As shown in FIGS. 20(d) and 20(e), the drive unit 25 may move the light source 2 so that the irradiation region R1 moves in the circumferential direction about the center Q1. FIG. 21 is a diagram schematically illustrating an example of the configuration of such an illumination device 1B. The drive unit 25 moves the light source 2 in the circumferential direction about the central axis Q2. In other words, the drive unit 25 revolves the light source 2 around the central axis Q2. As shown in FIG. 21, the drive unit 25 may include a drive source 251 such as a motor and an eccentric shaft 252. The eccentric shaft 252 is attached to the light source 2. The optical axis of the light source 2 is offset from the central axis Q2 in the Z direction. The central axis Q2 is a virtual axis that advances from the center Q1 along the Z direction toward the -Z side and follows the virtual light ray reflected by the wavelength separation filter 4. The drive source 251 rotates the eccentric shaft 252 around the central axis Q2. As a result, the light source 2 revolves around the central axis Q2, and the irradiation region R1 revolves around the center Q1. This revolution changes the proportion of the area of ​​each wavelength conversion member 3 in the irradiation region R1, and therefore the color of the fluorescence L1 can be changed.

[0185] 20( f), the irradiation region R1 of the excitation light L0 is shown as a rectangle. In FIG. 20( f), the irradiation region R1 spans the first wavelength conversion member 31 and the second wavelength conversion member 32. In this case, the lighting device 1B can emit fluorescence L1 in which the color of the first color temperature and the color of the second color temperature are mixed at a mixing ratio according to the ratio of the areas of the first wavelength conversion member 31 and the second wavelength conversion member 32 in the irradiation region R1. By moving the irradiation region R1 along the X direction, the area of ​​each wavelength conversion member 31 in the irradiation region R1 changes, and therefore the hue of the fluorescence L1 can be changed.

[0186] 22 is a diagram schematically illustrating an example of an optical system of an illumination device 1C according to a fourth embodiment. The illumination device 1C differs from the illumination device 1 according to the first embodiment in the shape of the wavelength conversion member 3.

[0187] As shown in FIG. 22 , the surface 3b of the wavelength conversion member 3 may have a non-flat surface. As a specific example, the surface 3b of the wavelength conversion member 3 may have a concave shape recessed toward the +Z side. That is, the surface 3b of the wavelength conversion member 3 may have a concave shape in which the center of the surface 3b is farther from the wavelength separation filter 4 than the periphery of the surface 3b. The depth (or height) of the surface 3b may be, for example, approximately 1 mm or more. As shown in FIG. 22 , the wavelength conversion member 3 may be positioned such that at least the center of the surface 3b faces the end surface 5b of the light-guiding member 5 in the Z direction. In the example of FIG. 22 , the surface 3b of the wavelength conversion member 3 has a semi-elliptical shape in a ZX cross section including the central axis of the light-guiding member 5. However, the shape of the surface 3b is not necessarily limited thereto. For example, the surface 3b may have a semicircular shape or a V-shape in the ZX cross section. The surface 3b may have a shape in the ZX cross section that extends uniformly along the Y direction, or may have, for example, a hemispherical, semi-ellipsoidal, conical or pyramidal shape. Also, as shown in Fig. 22 , the surface 3a of the wavelength conversion member 3 may have the same or similar shape as the surface 3b.

[0188] According to the lighting device 1C, the surface area of ​​the surface 3b of the wavelength conversion member 3 is relatively large. Therefore, the excitation light L0 can be incident on a wider irradiation area of ​​the surface 3b of the wavelength conversion member 3. This makes it possible to reduce the power density of the excitation light L0 on the surface 3b, and to reduce the temperature rise of the wavelength conversion member 3. Therefore, the degree of thermal degradation of the wavelength conversion member 3 can be reduced.

[0189] 22, the surface 3b of the wavelength conversion member 3 has a concave shape recessed toward the +Z side. This shape allows more of the fluorescence L1 emitted by the wavelength conversion member 3 to travel toward the center of the end surface 5b of the light-guiding member 5. This makes it possible to increase the amount of fluorescence L1 incident on the wavelength separation filter 4. Consequently, the illumination device 1C can emit the fluorescence L1 into the illumination space S1 with higher efficiency.

[0190] FIG. 23 is a diagram schematically illustrating another example of the shape of the wavelength conversion member 3. As shown in FIG. 23( a), the surface 3b of the wavelength conversion member 3 may have an uneven shape. That is, the surface 3b of the wavelength conversion member 3 may have an uneven shape in a ZX cross section including the central axis of the cylindrical surface 5a. In the example of FIG. 23( a), the surface 3b of the wavelength conversion member 3 has a linear uneven shape in the ZX cross section, but may also have a curved uneven shape. That is, each concave portion of the uneven shape of the surface 3b may have a V-shape, or may have a semicircular or semielliptical shape. Furthermore, multiple concave portions in the uneven shape may be arranged one-dimensionally or two-dimensionally. That is, multiple concave portions may be arranged one-dimensionally in the X direction or Y direction, or may be arranged two-dimensionally in the XY plane. When multiple concave portions are arranged one-dimensionally, each concave portion of the uneven shape of the surface 3b may have a shape in the ZX cross section that extends uniformly along the Y direction, for example. When multiple recesses are arranged two-dimensionally, each recess in the uneven shape of the surface 3b may have, for example, a hemispherical, semi-ellipsoidal, conical, or pyramidal shape. The depth (or height) of each recess in the uneven shape of the surface 3b may be, for example, about 1 mm or more. The wavelength conversion member 3 is positioned such that at least one recess in the surface 3b faces the end face 5b of the light-guiding member 5 in the Z direction.

[0191] 23(b), the surface 3b of the wavelength conversion member 3 may have a convex shape that bulges toward the -Z side. That is, the surface 3b of the wavelength conversion member 3 has a convex shape in which the center of the surface 3b is closer to the wavelength separation filter 4 than the periphery of the surface 3b. The height of the surface 3b may be, for example, about 1 mm or more. The wavelength conversion member 3 is positioned such that at least the center of the surface 3b faces the end surface 5b of the light-guiding member 5 in the Z direction.

[0192] 23, the surface 3b is non-planar, and therefore the surface area of ​​the surface 3b onto which the excitation light L0 is incident is large, which makes it possible to reduce the temperature rise of the wavelength conversion member 3 and reduce the degree of thermal degradation of the wavelength conversion member 3.

[0193] 24 is a diagram schematically illustrating another example of the optical system of the illumination device 1C according to the fourth embodiment. The illumination device 1C according to the other example of the fourth embodiment differs from the illumination device 1C in FIG. 22 in the configuration of the wavelength conversion member 3.

[0194] 24 shows a first wavelength conversion member 31 to a third wavelength conversion member 33 that are the same as or similar to those shown in Fig. 10 as the multiple wavelength conversion members 3. In the example of Fig. 24, the first wavelength conversion member 31, the second wavelength conversion member 32, and the third wavelength conversion member 33 are arranged in this order in the X direction. The first wavelength conversion member 31 may be in contact with the second wavelength conversion member 32, and the second wavelength conversion member 32 may be in contact with the third wavelength conversion member 33.

[0195] As shown in Fig. 24 , the surfaces 3b of the first to third wavelength conversion members 31 to 33 are non-flat and have a concave shape recessed toward the +Z side as a whole. That is, the concave surface is formed by the surfaces 3b of the first to third wavelength conversion members 31 to 33. The first to third wavelength conversion members 31 to 33 in Fig. 24 may each correspond to a portion obtained by dividing the wavelength conversion member 3 in Fig. 22 into three in the X direction. The surfaces 3b of the first to third wavelength conversion members 31 to 33 face the end face 5b of the light-guiding member 5 in the Z direction.

[0196] 24, a lighting device 1C may be provided with a plurality of light sources 2 corresponding to a plurality of wavelength conversion members 3. In the example of Fig. 24, a first light source 21 to a third light source 23 that are the same as or similar to those in Fig. 10 are shown as the plurality of light sources 2.

[0197] According to the fourth embodiment, the entire surfaces 3b of the first wavelength conversion member 31 to the third wavelength conversion member 33 are non-flat. This makes it possible to reduce the temperature rise of the first wavelength conversion member 31 to the third wavelength conversion member 33. In addition, in the example of Fig. 24, the entire surfaces 3b of the first wavelength conversion member 31 to the third wavelength conversion member 33 have a concave shape recessed toward the +Z side. This makes it possible for more of the fluorescence L1 emitted by each of the first wavelength conversion member 31 to the third wavelength conversion member 33 to be incident on the end surface 5b of the light-guiding member 5.

[0198] 25( a) and 25(b) are diagrams schematically illustrating other examples of the shape of the wavelength conversion member 3. As shown in FIGS. 25(a) and 25(b), each of the surfaces 3b of the first to third wavelength conversion members 31 to 33 may have a single concave shape. In the examples of FIGS. 25(a) and 25(b), the first to third wavelength conversion members 31 to 33 are aligned in the X direction, so the entire surfaces 3b of the first to third wavelength conversion members 31 to 33 have an uneven shape. As an example of the shape of each surface 3b, as shown in FIG. 25(a), it may have a semi-elliptical or semi-circular shape in the ZX cross section, or as shown in FIG. 25(b), it may have a V-shaped shape in the ZX cross section. The shape of each surface 3b in the ZX cross section may be a shape that extends uniformly along the Y direction, or it may have, for example, a hemispherical, semi-elliptical, conical, or pyramidal shape.

[0199] 25(c), the surfaces 3b of the first to third wavelength conversion members 31 to 33 may each have an uneven shape. Examples of the uneven shape on each surface 3b are the same as or similar to those shown in FIG. 23(a).

[0200] Furthermore, each of the surfaces 3b of the first to third wavelength conversion members 31 to 33 may have a single convex shape that bulges toward the +Z side. Examples of the convex shape on each surface 3b are the same as or similar to that shown in FIG.

[0201] The first to third wavelength conversion members 31 to 33 may have the same shape, so that the first to third wavelength conversion members 31 to 33 emit the fluorescence L1 to the same extent. Therefore, the lighting device 1C can emit fluorescence L1 with less color unevenness into the illumination space S1.

[0202] As described above, the lighting devices 1, 1A to 1C have been described in detail. However, the above description is merely an example in all respects, and the lighting devices 1, 1A to 1C are not limited thereto. It is understood that countless variations not illustrated can be envisioned without departing from the scope of this disclosure. The configurations described in the above embodiments and variations (or aspects) can be combined or omitted as appropriate, as long as they are not mutually inconsistent.

[0203] It goes without saying that all or part of the components constituting each of the above-described embodiments and various modified examples (or each aspect) can be combined as appropriate within the scope of not causing any contradiction.

[0204] This disclosure includes the following:

[0205] In one embodiment, (1) an illumination device includes one or more light sources that emit excitation light; one or more wavelength conversion members that receive the excitation light from the light sources and emit fluorescence based on the excitation light, the fluorescence having a spectrum different from that of the excitation light; one or more wavelength separation filters that guide the excitation light from the light sources to the wavelength conversion members and receive the fluorescence from the wavelength conversion members; a light-guiding member that has a cylindrical surface and through which the fluorescence from the wavelength separation filters travels inside an area surrounded by the cylindrical surface while repeatedly reflected by the cylindrical surface; and a lens optical system that includes a lens on which the fluorescence emitted from the light-guiding member is incident and that forms an image of the emission surface of the light-guiding member on a virtual image plane.

[0206] (2) In the lighting device of (1) above, the wavelength separation filter may include a dielectric multilayer film that reflects one of the excitation light and the fluorescence and transmits the other of the excitation light and the fluorescence, and the light-guiding member may include a first transparent member having a first inclined surface on which the dielectric multilayer film is located, the exit surface on the lens optical system side, and a first side surface that is at least a part of the cylindrical surface that connects the periphery of the first inclined surface and the periphery of the exit surface.

[0207] (3) In the lighting device of (2) above, the light-guiding member may further include a second transparent member, and the second transparent member has a second inclined surface that sandwiches the dielectric multilayer film together with the first inclined surface of the first transparent member, an end surface opposite to the second inclined surface, and a second side surface that connects the second inclined surface and the end surface.

[0208] (4) In the lighting device of (1) above, the light-guiding member can include a rod lens located away from the wavelength separation filter and having an end surface onto which the fluorescence from the wavelength separation filter is incident, an exit surface on the lens optical system side, and a side surface that is the cylindrical surface connecting the end surface and the exit surface.

[0209] (5) In the illumination device of (4) above, the wavelength separation filter can include a dichroic prism having a dielectric multilayer film that reflects one of the excitation light and the fluorescent light and transmits the other of the excitation light and the fluorescent light.

[0210] (6) In the lighting device of (4) above, the wavelength separation filter can include a plate-shaped transparent substrate having a first surface and a second surface, and a dielectric multilayer film located on the first surface or the second surface of the transparent substrate, which reflects one of the excitation light and the fluorescent light and transmits the other of the excitation light and the fluorescent light.

[0211] (7) In the lighting device according to any one of (1) to (6) above, the one or more wavelength conversion members may include a first wavelength conversion member and a second wavelength conversion member that emit the fluorescence having different spectrums from each other.

[0212] (8) In the lighting device of (7) above, the one or more light sources may include a first light source that emits the excitation light toward the first wavelength conversion member, and a second light source that emits the excitation light toward the second wavelength conversion member.

[0213] (9) In the lighting device of (8) above, the first wavelength conversion member and the second wavelength conversion member can be adjacent to each other, and the one or more wavelength separation filters can include a single wavelength separation filter, which can guide the excitation light from the first light source to the first wavelength conversion member, can guide the excitation light from the second light source to the second wavelength conversion member, and can guide the fluorescence from the first wavelength conversion member and the second wavelength conversion member to the light-guiding member.

[0214] (10) In the lighting device of (8) above, the one or more wavelength separation filters may include a first wavelength separation filter that guides the excitation light from the first light source to the first wavelength conversion member and onto which the fluorescence from the first wavelength conversion member is incident, and a second wavelength separation filter that guides the excitation light from the second light source to the second wavelength conversion member and onto which the fluorescence from the second wavelength conversion member is incident.

[0215] (11) In the lighting device of (10) above, a first peak wavelength of the fluorescence emitted by the first wavelength conversion member may be longer than a second peak wavelength of the fluorescence emitted by the second wavelength conversion member, and the second peak wavelength may be longer than an excitation peak wavelength of the excitation light. The second wavelength separation filter can guide the fluorescence from the second wavelength conversion member to the first wavelength separation filter. The first wavelength separation filter can combine the fluorescence from the first wavelength conversion member and the fluorescence from the second wavelength separation filter and guide the combined fluorescence to the light-guiding member.

[0216] (12) In the lighting device of (11) above, the one or more wavelength converting members may further include a third wavelength converting member that emits the fluorescence having a third peak wavelength that is shorter than the second peak wavelength and longer than the excitation peak wavelength, the one or more light sources may further include a third light source that emits the excitation light to the third wavelength converting member, and the one or more wavelength separation filters may further include a third wavelength separation filter that guides the excitation light from the third light source to the third wavelength converting member and guides the fluorescence from the third wavelength converting member to the second wavelength separation filter, The long separation filter can combine the fluorescence from the third wavelength separation filter and the fluorescence from the second wavelength conversion member and guide the combined fluorescence to the first wavelength separation filter, and the cutoff wavelength of the first wavelength separation filter can be set to a value between the first peak wavelength and the second peak wavelength, the cutoff wavelength of the second wavelength separation filter can be set to a value between the second peak wavelength and the third peak wavelength, and the cutoff wavelength of the third wavelength separation filter can be set to a value between the third peak wavelength and the excitation peak wavelength.

[0217] (13) In the lighting device of (11) or (12) above, the first wavelength conversion member can be aligned with the first wavelength separation filter in a first direction and can be positioned on a first side relative to the first wavelength separation filter, the second wavelength conversion member can be aligned with the second wavelength separation filter in the first direction and can be positioned on the first side relative to the second wavelength separation filter, and the first wavelength separation filter can be aligned with the second wavelength separation filter in a second direction intersecting the first direction.

[0218] (14) The lighting device of (13) above may further include a cooling member that supports both the first wavelength conversion member and the second wavelength conversion member and has a thermal conductivity higher than that of both the first wavelength conversion member and the second wavelength conversion member.

[0219] (15) In the lighting device of (11) or (12) above, the first wavelength conversion member can be aligned with the first wavelength separation filter in a first direction and can be located on a first side relative to the first wavelength separation filter, the second wavelength conversion member can be aligned with the second wavelength separation filter in the first direction and can be located on a second side opposite to the first side relative to the second wavelength separation filter, and the first wavelength separation filter can be aligned with the second wavelength separation filter in a second direction intersecting the first direction.

[0220] (16) In the lighting device according to any one of (13) to (15) above, the first wavelength separation filter, the second wavelength separation filter, and the light guide member may be aligned in the second direction.

[0221] (17) In the lighting device of (11) or (12) above, the first wavelength separation filter and the second wavelength separation filter can be aligned in a first direction, and the first wavelength separation filter and the light-guiding member can be aligned in a second direction that intersects the first direction.

[0222] (18) In the lighting device of (17) above, the one or more wavelength conversion members may further include a third wavelength conversion member, and the third wavelength conversion member may emit the fluorescence having a peak wavelength shorter than the peak wavelength of the fluorescence emitted by the second wavelength conversion member and longer than the peak wavelength of the excitation light, the one or more light sources may further include a third light source that emits the excitation light to the third wavelength conversion member, the one or more wavelength separation filters may further include a third wavelength separation filter that guides the excitation light from the third light source to the third wavelength conversion member and guides the fluorescence from the third wavelength conversion member to the second wavelength separation filter, and the second wavelength separation filter may guide the fluorescence from the third wavelength separation filter to the second wavelength separation filter, and the third wavelength separation filter may face the second wavelength separation filter in the second direction and be located on the light-guiding member side of the second wavelength separation filter.

[0223] (19) Any one of the lighting devices (10) to (18) above may further include a transparent member positioned between the dielectric multilayer film of the first wavelength separation filter and the dielectric multilayer film of the second wavelength separation filter, and supporting the dielectric multilayer film of the first wavelength separation filter and the dielectric multilayer film of the second wavelength separation filter.

[0224] (20) The lighting device of (10) above may further include a converging element into which the fluorescence from the first wavelength separation filter and the fluorescence from the second wavelength separation filter are incident from different directions, and the converging element can converge the fluorescence from the first wavelength separation filter and the fluorescence from the second wavelength separation filter and guide the converged fluorescence to the light-guiding member.

[0225] (21) The lighting device of (7) above may further include a drive unit that displaces the light source, the first wavelength conversion member and the second wavelength conversion member may be adjacent to each other, the wavelength separation filter may guide the excitation light from the light source to the first wavelength conversion member and the second wavelength conversion member, and the drive unit may displace the light source to move the irradiation area of ​​the excitation light relative to the first wavelength conversion member and the second wavelength conversion member.

[0226] (22) In the illumination device according to any one of (1) to (21) above, the surface of the wavelength conversion member on the wavelength separation filter side may have a convex, concave, or uneven shape.

[0227] REFERENCE SIGNS LIST 1 Illumination device 2 Light source 21 First light source 22 Second light source 3 Wavelength conversion member 31 First wavelength conversion member 32 Second wavelength conversion member 3b Surface 4 Wavelength separation filter 41 First wavelength separation filter 42 Second wavelength separation filter 412 Transparent member (second transparent member) 5 Light guide member 51 First transparent member 52 Second transparent member 6 Lens optical system 61 Lens 7 Housing 7a Opening

Claims

1. One or more light sources that emit excitation light; one or more wavelength conversion members that receive the excitation light from the light source and emit fluorescence having a spectrum different from that of the excitation light based on the excitation light; one or more wavelength separation filters that guide the excitation light from the light source to the wavelength conversion member and into which the fluorescence from the wavelength conversion member is incident; a light guiding member having a cylindrical surface, the fluorescence from the wavelength separation filter traveling inside the cylindrical surface while being repeatedly reflected by the cylindrical surface; a lens optical system including a lens onto which the fluorescence emitted from the light guiding member is incident, the lens optical system forming an image of an exit surface of the light guiding member on a virtual image plane; Equipped with the one or more wavelength converting members include a first wavelength converting member and a second wavelength converting member that emit the fluorescent light having different spectra from each other, The one or more light sources include a first light source that emits the excitation light toward the first wavelength conversion member; a second light source that emits the excitation light toward the second wavelength conversion member; 13. A lighting device comprising:

2. 2. The lighting device according to claim 1, the wavelength separation filter includes a dielectric multilayer film that reflects one of the excitation light and the fluorescent light and transmits the other of the excitation light and the fluorescent light, The light guiding member is an illumination device comprising: a first transparent member having a first inclined surface on which the dielectric multilayer film is located, an exit surface on the lens optical system side, and a first side surface which is at least a part of the cylindrical surface connecting a periphery of the first inclined surface and a periphery of the exit surface.

3. 3. The lighting device according to claim 2, The light guide member further includes a second transparent member, The second transparent member is a second inclined surface that sandwiches the dielectric multilayer film together with the first inclined surface of the first transparent member; an end surface opposite to the second inclined surface; a second side surface connecting the second inclined surface and the end surface; A lighting device comprising:

4. 2. The lighting device according to claim 1, The light guiding member is an end surface located away from the wavelength separation filter and on which the fluorescence from the wavelength separation filter is incident; an exit surface on the lens optical system side; a side surface which is the cylindrical surface and connects the end surface and the light exit surface; 1. An illumination device comprising a rod lens having a

5. 5. The lighting device according to claim 4, The wavelength separation filter is an illumination device comprising: a dichroic prism having a dielectric multilayer film that reflects one of the excitation light and the fluorescent light and transmits the other of the excitation light and the fluorescent light;

6. 5. The lighting device according to claim 4, The wavelength separation filter is A plate-shaped transparent substrate having a first surface and a second surface; a dielectric multilayer film located on the first surface or the second surface of the transparent base material, which reflects one of the excitation light and the fluorescent light and transmits the other of the excitation light and the fluorescent light; 13. A lighting device comprising:

7. 7. The lighting device according to claim 1, the first wavelength converting member and the second wavelength converting member are adjacent to each other, the one or more wavelength separation filters include a single wavelength separation filter; the single wavelength separation filter guides the excitation light from the first light source to the first wavelength conversion member, guides the excitation light from the second light source to the second wavelength conversion member, and guides the fluorescence from the first wavelength conversion member and the second wavelength conversion member to the light guiding member.

8. 7. The lighting device according to claim 1, The one or more wavelength separation filters include a first wavelength separation filter that guides the excitation light from the first light source to the first wavelength conversion member and into which the fluorescence from the first wavelength conversion member is incident; a second wavelength separation filter that guides the excitation light from the second light source to the second wavelength conversion member and into which the fluorescence from the second wavelength conversion member is incident; 13. A lighting device comprising:

9. 9. The lighting device according to claim 8, a first peak wavelength of the fluorescence emitted by the first wavelength converting member is longer than a second peak wavelength of the fluorescence emitted by the second wavelength converting member; the second peak wavelength is longer than the excitation peak wavelength of the excitation light, the second wavelength separation filter guides the fluorescence from the second wavelength conversion member to the first wavelength separation filter, The first wavelength separation filter combines the fluorescence from the first wavelength conversion member and the fluorescence from the second wavelength separation filter, and guides the combined fluorescence to the light guiding member.

10. 10. The lighting device according to claim 9, the one or more wavelength converting members further include a third wavelength converting member that emits the fluorescence having a third peak wavelength that is shorter than the second peak wavelength and longer than the excitation peak wavelength; The one or more light sources further include a third light source that emits the excitation light for the third wavelength conversion member, the one or more wavelength separation filters further include a third wavelength separation filter that guides the excitation light from the third light source to the third wavelength conversion member and guides the fluorescence from the third wavelength conversion member to the second wavelength separation filter, the second wavelength separation filter combines the fluorescence from the third wavelength separation filter and the fluorescence from the second wavelength conversion member and guides the combined fluorescence to the first wavelength separation filter; a cutoff wavelength of the first wavelength separation filter is set to a value between the first peak wavelength and the second peak wavelength, a cutoff wavelength of the second wavelength separation filter is set to a value between the second peak wavelength and the third peak wavelength, a cutoff wavelength of the third wavelength separation filter is set to a value between the third peak wavelength and the excitation peak wavelength.

11. 10. The lighting device according to claim 9, the first wavelength conversion member is aligned with the first wavelength separation filter in a first direction and is located on a first side with respect to the first wavelength separation filter; the second wavelength conversion member is aligned with the second wavelength separation filter in the first direction and is located on the first side with respect to the second wavelength separation filter, The first wavelength separation filter is aligned with the second wavelength separation filter in a second direction intersecting the first direction.

12. 12. The lighting device according to claim 11, A lighting device, further comprising a cooling member that supports both the first wavelength conversion member and the second wavelength conversion member and has a thermal conductivity higher than both the thermal conductivity of the first wavelength conversion member and the second wavelength conversion member.

13. 10. The lighting device according to claim 9, the first wavelength conversion member is aligned with the first wavelength separation filter in a first direction and is located on a first side with respect to the first wavelength separation filter; the second wavelength conversion member is aligned with the second wavelength separation filter in the first direction and is located on a second side opposite to the first side with respect to the second wavelength separation filter, The first wavelength separation filter is aligned with the second wavelength separation filter in a second direction intersecting the first direction.

14. 12. The lighting device according to claim 11, The first wavelength separation filter, the second wavelength separation filter, and the light guiding member are aligned in the second direction.

15. 10. The lighting device according to claim 9, the first wavelength separation filter and the second wavelength separation filter are aligned in a first direction, The first wavelength separation filter and the light guiding member are aligned in a second direction intersecting the first direction.

16. 16. The lighting device according to claim 15, the one or more wavelength converting members further include a third wavelength converting member; the third wavelength converting member emits the fluorescence having a peak wavelength shorter than the peak wavelength of the fluorescence emitted by the second wavelength converting member and longer than the peak wavelength of the excitation light, The one or more light sources further include a third light source that emits the excitation light for the third wavelength conversion member, the one or more wavelength separation filters further include a third wavelength separation filter that guides the excitation light from the third light source to the third wavelength conversion member and guides the fluorescence from the third wavelength conversion member to the second wavelength separation filter, the second wavelength separation filter guides the fluorescence from the third wavelength separation filter to the second wavelength separation filter; the third wavelength separation filter faces the second wavelength separation filter in the second direction and is located on the light-guiding member side of the second wavelength separation filter.

17. 9. The lighting device according to claim 8, the illumination device further comprising a transparent member positioned between the dielectric multilayer film of the first wavelength separation filter and the dielectric multilayer film of the second wavelength separation filter, the transparent member supporting the dielectric multilayer film of the first wavelength separation filter and the dielectric multilayer film of the second wavelength separation filter.

18. 9. The lighting device according to claim 8, a confluence element into which the fluorescence from the first wavelength separation filter and the fluorescence from the second wavelength separation filter are incident from different directions, The combining element combines the fluorescence from the first wavelength separation filter and the fluorescence from the second wavelength separation filter, and guides the combined fluorescence to the light guiding member.

19. One or more light sources that emit excitation light; one or more wavelength conversion members that receive the excitation light from the light source and emit fluorescence having a spectrum different from that of the excitation light based on the excitation light; one or more wavelength separation filters that guide the excitation light from the light source to the wavelength conversion member and into which the fluorescence from the wavelength conversion member is incident; a light guiding member having a cylindrical surface, the fluorescence from the wavelength separation filter traveling inside the cylindrical surface while being repeatedly reflected by the cylindrical surface; a lens optical system including a lens into which the fluorescent light emitted from the light guiding member is incident, the lens optical system forming an image of an exit surface of the light guiding member on a virtual image plane; A drive unit that displaces the light source; Equipped with the one or more wavelength converting members include a first wavelength converting member and a second wavelength converting member that emit the fluorescent light having different spectra from each other, the first wavelength converting member and the second wavelength converting member are adjacent to each other, the wavelength separation filter guides the excitation light from the light source to the first wavelength conversion member and the second wavelength conversion member; The driving unit displaces the light source to move an irradiation area of ​​the excitation light with respect to the first wavelength conversion member and the second wavelength conversion member.

20. 20. The lighting device according to claim 1, further comprising: An illumination device, wherein a surface of the wavelength conversion member on the wavelength separation filter side has a convex, concave or uneven shape.