Lighting device

Abstract

This lighting device comprises a casing, a light source that emits excitation light, an optical system that is located in an internal space within the casing, a first member, and a second member. The casing has a first opening that opens to the exterior and a first portion that is provided with a second opening that opens to the exterior. The first member has a conversion unit that emits fluorescence in response to irradiation with the excitation light, and a base part to which the conversion unit is fixed. The second member is fixed to the casing from the first-opening side, the second member having a third opening through which the fluorescence passes. The optical system includes a filter that guides the excitation light from the light source to the conversion unit and guides the fluorescence from the conversion unit to the first opening, and a lens optical system that includes one or more lenses positioned on the optical axis of the fluorescence from a wavelength conversion unit to the first opening. The base part covers the second opening from the exterior side, the base part being fixed to the casing in a state that allows the base part to be retrieved to the exterior. The optical system is sandwiched between the second member and the inner surface of the casing.

Description

lighting equipment CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority from Japanese Application No. 2022-136540 (filed August 30, 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 There is an illumination device that projects fluorescence emitted by a phosphor in response to irradiation with excitation light onto an object or a target space (see, for example, the description in Patent Document 1).

[0004] JP 2013-4481 A

[0005] A lighting device is disclosed.

[0006] One aspect of the lighting device includes a housing, a light source, an optical system, a first member, and a second member. The housing has a first opening that opens to the outside and a first portion in which a second opening that opens to the outside is present. The light source emits excitation light. The optical system is located in the internal space of the housing. The first member includes a wavelength conversion unit that emits fluorescence having a wavelength spectrum different from that of the excitation light in response to irradiation of the excitation light from the light source, and a base unit to which the wavelength conversion unit is fixed. The second member is fixed to the housing from the first opening side and has a third opening through which the fluorescence passes. The optical system includes a wavelength separation filter that guides the excitation light from the light source to the wavelength conversion unit and guides the fluorescence from the wavelength conversion unit to the first opening, and a lens optical system including one or more lenses located on the optical path of the fluorescence from the wavelength conversion unit to the first opening. The base unit covers the second opening from the outside and is fixed to the housing in a manner that allows it to be removed from the outside. The wavelength converting unit is positioned in a state where it is exposed to the internal space, and the optical system is sandwiched between the second member and the inner surface of the housing.

[0007] FIG. 1 is a front view schematically illustrating the appearance of an example of an illumination device according to a first embodiment. FIG. 2 is a plan view schematically illustrating the appearance of an example of an illumination device according to the first embodiment. FIG. 3 is a cross-sectional view schematically illustrating a cross section of the example of an illumination device taken along line III-III in FIG. 2. FIG. 4 is a diagram for explaining an example of a method for assembling the illumination device according to the first embodiment. FIG. 5 is a bottom view schematically illustrating an example of a configuration of a first member. FIG. 6 is a plan view schematically illustrating an example of a configuration of a housing. FIG. 7 is a diagram schematically illustrating an example of a state in which the first member is removed from the housing. FIG. 8 is a front view schematically illustrating an example of an appearance of an illumination device according to a second embodiment. FIG. 9 is a diagram schematically illustrating an example of a state in which a heat dissipation member is removed from the illumination device according to the second embodiment. FIG. 10 is a front view schematically illustrating the appearance of another example of an illumination device according to the second embodiment. FIG. 11 is a plan view schematically illustrating an example of an appearance of an illumination device according to a third embodiment. FIG. 12 is a cross-sectional view schematically illustrating a first member and the vicinity of the first member in a cross section of an example of an illumination device according to a third embodiment. FIG. 13 is a bottom view schematically illustrating an example of the configuration of the first member in the illumination device according to the third embodiment. FIG. 14 is a view schematically illustrating an example of a state in which the base portion is released from the housing in the illumination device according to the third embodiment. FIG. 15 is a cross-sectional view schematically illustrating an example of the configuration of an illumination device according to a fourth embodiment. FIG. 16 is a front view schematically illustrating the appearance of an illumination device according to another first example. FIG. 17 is a cross-sectional view schematically illustrating an example of a cross section of an illumination device according to another first example, taken at a position corresponding to line III-III in FIG. 2. FIG. 18 is a cross-sectional view schematically illustrating an example of a cross section of an illumination device according to another second example, taken at a position corresponding to line III-III in FIG. 2. FIG. 19 is a cross-sectional view schematically illustrating an example of a cross section of an illumination device according to a third example, taken at a position corresponding to line III-III in FIG. 2. FIG. 20 is a cross-sectional view schematically illustrating the configuration of an example of an attachment mechanism in an illumination device according to a fourth example. 21 and 22 are cross-sectional views schematically illustrating an example of a state in which a first member is being removed from a housing of a lighting device having an attachment mechanism according to an embodiment of the present invention.Fig. 23 is a cross-sectional view schematically showing the configuration of another example of the attachment mechanism in a lighting device according to another fourth example. Fig. 24 is a cross-sectional view schematically showing an example of a state in the middle of removing a first member from a housing in a lighting device having the attachment mechanism according to another example. Fig. 25 is a cross-sectional view schematically showing an example of a state after removing a first member from a housing in a lighting device having the attachment mechanism according to another example.

[0008] 2. Description of the Related Art There is an illumination device that projects fluorescence emitted by a phosphor in response to irradiation with excitation light onto an object or a target space.

[0009] This lighting device has room for improvement in terms of extending its life and making it easier to handle.

[0010] Therefore, the inventors of the present disclosure have created a technology that can extend the life of lighting devices and make them easier to handle.

[0011] In this regard, lighting devices according to various embodiments will be described below with reference to the drawings.

[0012] In the drawings, parts having the same or similar configurations and functions are denoted by the same reference numerals, and redundant explanations will be omitted below. The drawings are schematic. A right-handed XYZ coordinate system is shown in Figures 1 to 25. In this XYZ coordinate system, a first direction in which light is emitted from the lighting device 1 is defined as the -Z direction, a direction perpendicular to the first direction is defined as the +X direction, and a direction perpendicular to both the -Z direction and the +X direction is defined as the +Y direction.

[0013] 1. First Embodiment A lighting device 1 according to a first embodiment will be described with reference to FIGS. 1 to 7. FIG.

[0014] FIG. 1 is a front view schematically illustrating the appearance of an example of an illumination device 1 according to the first embodiment. FIG. 2 is a plan view schematically illustrating the appearance of an example of an illumination device 1 according to the first embodiment. FIG. 3 is a cross-sectional view schematically illustrating a cross section of the example of the illumination device 1 taken along line III-III in FIG. 2. FIG. 4 is a diagram for explaining an example of a method for assembling the illumination device 1 according to the first embodiment. FIG. 5 is a bottom view schematically illustrating an example of a configuration of a first member 40 (described later). FIG. 6 is a plan view schematically illustrating an example of a configuration of a housing 10 (described later). FIG. 7 is a diagram schematically illustrating an example of a manner in which the first member 40 is removed from the housing 10. Here, the cross section of the illumination device 1 taken along line III-III in FIG. 2 is a cross section including a first optical axis Ax1 and a second optical axis Ax2 (described later) of the illumination device 1. In FIGS. 4, 5, and 7, hidden lines depicting examples of outer edges of some components are schematically indicated by thin dashed lines.

[0015] As shown in Fig. 3, the lighting device 1 is a device that can emit fluorescence L1 as illumination light into an illumination space S1. In the example of Fig. 3, an example of the outer edge of the fluorescence L1 is schematically shown by a thin two-dot chain line. The illumination space S1 is, for example, an interior space of a building. The lighting device 1 is disposed, for example, on a ceiling portion located above the illumination space S1.

[0016] 1 to 3 , the lighting device 1 includes a housing 10, a light source 20, an optical system 30, a first member 40, and a second member 50. In the first embodiment, the lighting device 1 also includes a holding mechanism 60.

[0017] <1-1. Housing> The housing 10 is a portion that houses the optical system 30. The housing 10 has an internal space 10is. The internal space 10is is a space surrounded by the inner surface 10if of the housing 10. The housing 10 has a first opening 10a. The housing 10 also has a first portion 12 in which a second opening 10b is present. The first opening 10a and the second opening 10b each open to the outside Ex1 of the housing 10.

[0018] The housing 10 may be, for example, a cylindrical object (also referred to as a cylindrical body). In this case, the second opening 10b is located on the opposite side of the internal space 10is from the first opening 10a. The housing 10 has a cylindrical portion 11 and a first portion 12. The cylindrical portion 11 and the first portion 12 may be formed of a single member, or may have a structure in which two or more members are integrated by connecting, adhering, joining, or the like.

[0019] The tubular portion 11 may have a hollow space along the −Z direction as the first direction, for example. The tubular portion 11 may have a longitudinal direction along the −Z direction as the first direction, for example. This tubular portion 11 may have, for example, a linear (also referred to as an I-shaped) tubular portion having a longitudinal direction along the −Z direction as the first direction. The tubular portion 11 may be any of a cylindrical portion having a cylindrical hollow space, an elliptical cylindrical portion having an elliptical cylindrical hollow space, and a rectangular cylindrical portion having a rectangular cylindrical hollow space. The tubular portion 11 has a first end E1 and a second end E2 at both ends in the longitudinal direction. The first end E1 is the portion of the tubular portion 11 located at the end on the −Z direction side as the first direction. The second end E2 is the portion of the tubular portion 11 located at the end on the +Z direction side as the opposite direction to the first direction.

[0020] The first opening 10a is formed, for example, by the inner peripheral surface of the first end E1. In other words, the first opening 10a opens in the −Z direction, which is the first direction, at the end of the housing 10 in the −Z direction, which is the first direction. The cross-sectional shape of the first opening 10a may be, for example, a circular shape. The cross-sectional shape of the first opening 10a may be the shape of a cross section of the first opening 10a perpendicular to a direction along the second optical axis Ax2, which will be described later. The cross-sectional shape of the first opening 10a is not limited to a circular shape, and may be another shape, such as a polygonal shape or an elliptical shape.

[0021] The first portion 12 protrudes inward from the second end E2 of the cylindrical portion 11. The first portion 12 may be, for example, a plate-shaped portion having a second opening 10b. In other words, the first portion 12 has the second opening 10b as a through-hole. The second opening 10b opens in the +Z direction at the +Z-direction end of the housing 10. In other words, the second opening 10b is a hole that penetrates the first portion 12 in the +Z direction. In the example of FIG. 6 , the cross-sectional shape of the second opening 10b is circular. The cross-sectional shape of the second opening 10b may be the shape of a cross-section of the second opening 10b perpendicular to the direction in which the second opening 10b penetrates the first portion 12. The cross-sectional size of the second opening 10b may or may not be constant in the direction in which the second opening 10b penetrates the first portion 12. For example, the inner circumferential surface of the second opening 10b may be inclined such that the cross-sectional size of the second opening 10b decreases toward the internal space 10is. The shape of the second opening 10b is not limited to a circular shape and may be other shapes such as a polygonal shape or an elliptical shape. The diameter (also referred to as the second diameter) d2 of the second opening 10b may be smaller than the diameter (also referred to as the first diameter) d1 of the first opening 10a.

[0022] If, for example, an aluminum alloy is used as the material for the housing 10, it is possible to reduce the weight and improve the rigidity of the lighting device 1. The material for the housing 10 is not limited to an aluminum alloy, and may be other materials such as a synthetic resin.

[0023] In the example of FIG. 3 , the cylindrical portion 11 has a first introduction opening 10c that opens to the outside Ex1 of the housing 10. The first introduction opening 10c is an opening that allows the excitation light L0 from the light source 20 to pass through and guides the excitation light L0 into the internal space 10is of the housing 10. The first introduction opening 10c is located in a first predetermined portion of the cylindrical portion 11 between the first end E1 and the second end E2. The first predetermined portion may be a portion of the cylindrical portion 11 that is intermediate between the first end E1 and the second end E2 in the −Z direction, which is the first direction, or may be a portion of the cylindrical portion 11 that is closer to the first end E1 or the second end E2 from this intermediate portion. The first introduction opening 10c may penetrate the cylindrical portion 11 along the −X direction, which is the second direction.

[0024] The cylindrical portion 11 may have, for example, a thin portion 111 and a thick portion 112. The thick portion 112 has a thickness greater than that of the thin portion 111. The thick portion 112 is a portion that protrudes outward beyond the thin portion 111. The thick portion 112 may be located in an annular shape along the circumferential direction of the cylindrical portion 11. The thick portion 112 is located in a second predetermined portion of the cylindrical portion 11 between the first end E1 and the second end E2. The second predetermined portion may be a portion of the cylindrical portion 11 intermediate between the first end E1 and the second end E2 in the −Z direction as the first direction, or may be a portion from this intermediate portion closer to the first end E1 or the second end E2. The first introduction opening 10c may penetrate the cylindrical portion 11 at the thick portion 112.

[0025] <1-2. Light Source> The light source 20 can emit excitation light L0. In FIG. 3, an example of the outer edge of the excitation light L0 is schematically shown by a thin dashed line, and an example of the optical axis (also referred to as the first optical axis) Ax1 of the light source 20 is schematically shown by a thin dashed line. In the example of FIG. 3, the first optical axis Ax1 is positioned along the −X direction as the second direction. The second direction along the first optical axis Ax1 may be slightly inclined with respect to the −X direction. In other words, the second direction may not be perpendicular to the first direction, but may intersect with the first direction.

[0026] The light source 20 has an emission portion (e.g., an emission surface) 20e that emits excitation light L0. For example, light having a peak intensity within a wavelength range from 380 nm to 415 nm is used as the excitation light L0. A specific example of the excitation light L0 is purple light having a wavelength (also referred to as a first peak wavelength) that maximizes its intensity near 405 nm. The excitation light L0 is not necessarily limited to purple light, and may be, for example, blue light having a first peak wavelength near 450 nm.

[0027] The light source 20 may be, 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 portion 20e may be, for example, an emission end of the 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 this light emitting element.

[0028] In the example of FIG. 3 , the light source 20 is fixed to the housing 10 by a mounting member 200. In this case, the lighting device 1 includes the mounting member 200. The mounting member 200 includes a first holding portion 21 and a protruding portion 22. The first holding portion 21 holds the light source 20. The light source 20 may be fixed to the first holding portion 21 by adhesive bonding, fitting, joining, fastening, or the like. The protruding portion 22 is a portion protruding from the first holding portion 21 in the −X direction, which is the second direction. The protruding portion 22 may have, for example, a cylindrical shape with a hollow space 22is penetrating in the −X direction, which is the second direction. The protruding portion 22 is positioned, for example, in a state inserted into the first introduction opening 10c. The first holding portion 21 is positioned, for example, in contact with or in close proximity to the outer circumferential surface of the cylindrical portion 11 (e.g., the thick portion 112). The mounting member 200 may be fixed to the housing 10 with a plurality of screws, or may be fixed to the housing 10 by fitting the male threaded portion on the outer peripheral surface of the protrusion 22 into the female threaded portion on the inner peripheral surface of the first introduction opening 10c, or may be fixed to the housing 10 by adhesive bonding, joining, or the like. The light source 20 may be fixed to the housing 10 using a separate member without using the mounting member 200, or may be directly fixed to the housing 10 by adhesive bonding, fitting, joining, fastening, or the like.

[0029] <1-3. First Member> The first member 40 has a base portion 41 and a wavelength converting portion 422. The first member 40 may have the base portion 41 and a phosphor substrate 42 including the wavelength converting portion 422.

[0030] <1-3-1. Phosphor Substrate> The phosphor substrate 42 includes a second holding portion 421 and a wavelength conversion portion 422 .

[0031] The wavelength conversion unit 422 is positioned in a state where it is exposed to the internal space 10is of the housing 10. In response to irradiation with excitation light L0 from the light source 20, the wavelength conversion unit 422 emits fluorescence L1 having a wavelength spectrum different from that of the excitation light L0. In the example of Fig. 3, the wavelength conversion unit 422 has a surface that is exposed to the internal space 10is in the -Z direction, which is the first direction. Here, the state of being exposed to the internal space 10is includes a state where light from the internal space 10is can be irradiated.

[0032] The wavelength conversion unit 422 includes a phosphor. For example, the wavelength at which the intensity of the fluorescence L1 exhibits a maximum value is greater than the first peak wavelength of the excitation light L0. The fluorescence L1 is visible light. The wavelength conversion unit 422 has, for example, a plate-like or film-like shape. The thickness direction of the wavelength conversion unit 422 is set, for example, in the direction along the second optical axis Ax2 described below.

[0033] The wavelength conversion portion 422 is made of a wavelength conversion material (also called 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 converting portion 422 may contain, for example, (Sr, Ba, Ca) as a wavelength converting 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 converting portion 422 may contain, for example, SrSi as a wavelength converting 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 converting portion 422 may contain, for example, Y:Mn as a wavelength converting 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 portion 422 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 section 422 contains multiple types of wavelength conversion materials corresponding to multiple colors of light, the wavelength conversion section 422 can emit fluorescence L1 with high color rendering. Specifically, if the excitation light L0 is light having a first peak wavelength in the range of 380 nm to 415 nm and the wavelength conversion section 422 contains phosphors corresponding to the three colors of light, red, green, and blue, the color rendering of the fluorescence L1 can be improved. Furthermore, the wavelength conversion section 422 may contain a resin such as a binder for binding the phosphor particles together.

[0034] The second holding portion 421 is a portion that holds the wavelength conversion portion 422. The second holding portion 421 may hold the wavelength conversion portion 422 from the +Z direction side. For example, a plate-shaped member is used for the second holding portion 421. The second holding portion 421 and the wavelength conversion portion 422 form an integrated phosphor substrate 42. The second holding portion 421 may have a recess filled with the wavelength conversion portion 422, or may have a plate surface on which the wavelength conversion portion 422 is attached. The material of the second holding portion 421 may be, for example, a metal material or another inorganic material such as ceramics.

[0035] Here, if the material of the second holding unit 421 has a higher thermal conductivity than the wavelength conversion unit 422, the second holding unit 421 can increase the rate at which heat dissipates from the wavelength conversion unit 422. This can reduce the degree to which the wavelength conversion unit 422 is deteriorated by heat. For example, a metal material with high thermal conductivity is used as the material of the second holding unit 421. Examples of the metal material that can be used 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.

[0036] Furthermore, the surface of the second holding unit 421 may have a property of reflecting the excitation light L0 (also referred to as reflectivity). For example, the reflectivity of the surface of the second holding unit 421 with respect to the excitation light L0 may be 60% or more, 80% or more, or 90% or more. In this case, the excitation light L0 that has passed through the wavelength conversion unit 422 is reflected by the surface of the second holding unit 421 and then re-enters the wavelength conversion unit 422. This may increase the amount of fluorescence L1 emitted by the wavelength conversion unit 422. Here, for example, if the metal material of the second holding unit 421 is Al, Mg, Ag, Fe, Cr, or Co, the reflectivity of visible light on the surface of the second holding unit 421 increases, and the amount of fluorescence L1 emitted by the wavelength conversion unit 422 in response to the excitation light L0 may increase.

[0037] <1-3-2. Base> The base 41 is a portion to which the wavelength conversion unit 422 is fixed. The wavelength conversion unit 422 may be fixed to the base 41 via, for example, a second holding unit 421. In other words, the phosphor substrate 42 may be fixed to the base 41. The second holding unit 421 may be fixed to the base 41 using, for example, grease having thermal conductivity and adhesive properties. The second holding unit 421 may also be fixed to the base 41 by, for example, joining, bonding, fitting, or fastening using solder or the like without using grease or the like.

[0038] The base portion 41 is positioned in a state where it covers the second opening 10b from the outside Ex1 side of the housing 10. In other words, the base portion 41 is positioned in a state where it covers the second opening 10b from the outside Ex1 on the second end E2 side of the housing 10. In the examples of Figures 1 to 3, the base portion 41 is positioned in a state where it covers the second end E2, the first portion 12, and the second opening 10b in the -Z direction as the first direction.

[0039] Furthermore, the base unit 41 is fixed to the housing 10 in a state in which it can be removed toward the outside Ex1 of the housing 10. In other words, the first member 40 is fixed to the housing 10 in a state in which it can be removed toward the outside Ex1 of the housing 10. As a result, the base unit 41 is in a state in which it fixes the wavelength conversion unit 422 to the housing 10. Then, the base unit 41 to which the wavelength conversion unit 422 is fixed can be removed from the housing 10. For example, the base unit 41 can be removed from the portion on the second end E2 side of the housing 10 in the +Z direction.

[0040] For example, a configuration may be adopted in which the base portion 41 is fixed to the housing 10 by screwing. For example, as shown in FIGS. 2 and 4 to 6 , the base portion 41 may be fastened to the housing 10 by inserting a male screw member Sw1 into a through hole Th1 of the base portion 41 and fitting it into a screw hole Sh1 of the housing 10. More specifically, the base portion 41 may be fastened to the housing 10 by multiple pairs of a through hole Th1, a male screw member Sw1, and a screw hole Sh1. In the example of FIGS. 2 and 4 to 6 , the base portion 41 has, as the multiple through holes Th1, three through holes Th1 that each penetrate in the −Z direction as the first direction. The housing 10 has, as the multiple screw holes Sh1, three screw holes Sh1 that are each recessed in the −Z direction as the first direction at the second end E2.

[0041] According to this configuration, as shown in Fig. 7 , by removing the plurality of male screw members Sw1 from the plurality of screw holes Sh1, the base portion 41 can be removed from the housing 10 toward the outside Ex1 of the housing 10. In other words, the first member 40 can be removed from the housing 10 toward the outside Ex1 of the housing 10. In Fig. 4 , in order to avoid complicating the illustration, an example of the outer edges of two of the three screw holes Sh1 are schematically shown by thin dashed lines indicating hidden lines.

[0042] The base portion 41 may include, for example, a main body portion 411 and a protrusion portion 412. The main body portion 411 and the protrusion portion 412 may be configured as a single member, or may have a structure in which two or more members are integrated by connecting, adhering, joining, or the like.

[0043] The main body 411 is a portion fixed to the housing 10 and covers the second opening 10b from the exterior Ex1 side of the housing 10. The main body 411 may have a surface (also referred to as a first surface) 411b that covers the second opening 10b from the exterior Ex1 side of the housing 10. The first surface 411b may be in contact with or close to the second end E2 of the housing 10 and a surface (also referred to as a second surface) 12u on the exterior Ex1 side of the first part 12. The main body 411 may be, for example, a plate-shaped portion. In the example of FIGS. 1 to 3, the main body 411 is a disk-shaped portion, and the first surface 411b faces the −Z direction as a first direction, and the second surface 12u faces the +Z direction as a direction opposite to the first direction.

[0044] The convex portion 412 is a portion that protrudes from the main body portion 411 in the −Z direction, which is the first direction. More specifically, the convex portion 412 protrudes, for example, from the first surface 411b of the main body portion 411 in the −Z direction. The shape of the convex portion 412 may be, for example, a cylindrical shape such as a cylindrical, elliptical, or rectangular column, or a truncated cone shape such as a truncated elliptical cone or truncated pyramid. In this case, the convex portion 412 has a surface (also referred to as a third surface) 412b facing the −Z direction, which is the first direction. In the examples of FIGS. 1 to 6, the convex portion 412 has a cylindrical shape. The convex portion 412 may be fitted into the second opening 10b from the exterior Ex1 side of the housing 10. The wavelength conversion portion 422 may be fixed on the convex portion 412. For example, the phosphor substrate 42 including the wavelength conversion unit 422 may be fixed on the third surface 412b of the convex portion 412. According to this configuration, when assembling the lighting device 1, the convex portion 412 of the base portion 41 is fitted into the second opening 10b from the outside Ex1 of the housing 10, thereby aligning the wavelength conversion unit 422 easily.

[0045] If the material of the base portion 41 has a higher thermal conductivity than the wavelength conversion portion 422, the base portion 41 can increase the rate at which heat dissipates from the wavelength conversion portion 422. In other words, the base portion 41 can function as a heat sink. This can reduce the degree to which the wavelength conversion portion 422 is deteriorated by heat. For example, the base portion 41 can be made of a metal material with high thermal conductivity. Examples of such metal materials include Cu, Al, Mg, Au, Ag, Fe, Cr, Co, Be, Mo, W, and alloys. The material of the main body 411 and the material of the protrusion 412 may be the same or different.

[0046] 1-4. Optical System The optical system 30 is located in the internal space 10is of the housing 10. The optical system 30 includes a wavelength separation filter 31 and a lens optical system 32. In the example of FIG. 3 , an outer diameter (also referred to as a third diameter) d3 of the optical system 30 when viewed in a planar perspective view in a direction along the second optical axis Ax2 is smaller than a diameter (first diameter) d1 of the first opening 10a of the housing 10.

[0047] <1-4-1. Wavelength Separation Filter> The excitation light L0 from the light source 20 is incident on the wavelength separation filter 31. The wavelength separation filter 31 guides the excitation light L0 from the light source 20 to the wavelength conversion section 422 of the first member 40. The wavelength separation filter 31 also guides the fluorescence L1 from the wavelength conversion section 422 to the first opening 10a. More specifically, the wavelength separation filter 31 guides the fluorescence L1 from the wavelength conversion section 422 to a third opening 50a of the second member 50, which will be described later.

[0048] 3, the wavelength conversion unit 422, the wavelength separation filter 31, and the first opening 10a are aligned in the −Z direction, which is the first direction. The light source 20 and the wavelength separation filter 31 are aligned in the −X direction, which is the second direction intersecting the first direction. In this case, the wavelength separation filter 31 reflects the excitation light L0 from the light source 20 toward the wavelength conversion unit 422, and transmits the fluorescence L1 from the wavelength conversion unit 422 toward the first opening 10a. With this configuration, the size of the illumination device 1 in the −X direction, which is the second direction, can be reduced.

[0049] The wavelength separation filter 31 may be, for example, a dichroic mirror (also referred to as a dichroic film). As shown in FIG. 3 , the wavelength separation filter 31 includes, for example, a substrate 311 and a dielectric multilayer film 312. The substrate 311 may be, for example, a transparent member containing one or more materials selected from the group consisting of glass and resin. The substrate 311 may have, for example, a flat plate shape. The substrate 311 has a first plate surface 3 a and a second plate surface 3 b. In the example shown in FIG. 3 , the first plate surface 3 a is the surface of the substrate 311 that is located on the side of the light source 20 and the wavelength conversion unit 422. The second plate surface 3 b is the surface of the substrate 311 that is located on the opposite side from the first plate surface 3 a. The dielectric multilayer film 312 may be, for example, located on the first plate surface 3 a or the second plate surface 3 b of the substrate 311.

[0050] The dielectric multilayer film 312 has a structure in which, for example, thin dielectric films are repeatedly stacked. Examples of the dielectric film include silicon oxide (SiO ２ ), titanium oxide (TiO ２ ), aluminum oxide (Al ２ O ３), zirconium oxide (ZrO ２ ), tantalum oxide (Ta ２ O ５ ) and niobium oxide (Nb ２ O ３ ) is used. For example, by appropriately setting the thicknesses of the multiple dielectric thin films constituting the dielectric multilayer film 312, a spectral transmittance that reflects the excitation light L0 and transmits the fluorescence L1 in the dielectric multilayer film 312 can be achieved. Here, the reflectance of the wavelength separation filter 31 for the excitation light L0 may be, for example, 80% or more, 90% or more, or 95% or more. The transmittance of the wavelength separation filter 31 for the fluorescence L1 may be, for example, 80% or more, 90% or more, or 95% or more.

[0051] The angle α1 formed between the wavelength separation filter 31 and a second optical axis Ax2 (described later) is the angle formed between the first plate surface 3 a of the substrate 311 and the second optical axis Ax2. In Fig. 3 , an example of the angle α1 is indicated by a thin, arc-shaped arrow. In the example of Fig. 3 , the angle α1 is set to approximately 45 degrees. Here, if the first optical axis Ax1 and the second optical axis Ax2 are not perpendicular but intersect with each other, the angle α1 may be an angle other than 45 degrees.

[0052] The wavelength separation filter 31 may have a dielectric multilayer film that separates wavelengths on the first plate surface 3 a, and an anti-reflection film on the second plate surface 3 b, which reduces the risk of a decrease in the light intensity of the excitation light L0 and the fluorescence L1 due to light absorption by the wavelength separation filter 31 compared to when the dielectric multilayer film is located on the second plate surface 3 b.

[0053] <1-4-2. Lens Optical System> The lens optical system 32 includes one or more lenses 321 positioned on the optical path of the fluorescence L1 from the wavelength conversion unit 422 in the internal space 10is of the housing 10 to the first opening 10a.

[0054] In the example of FIG. 3 , the lens optical system 32 includes one or more lenses 321: a first lens 321a, a second lens 321b, and a third lens 321c. In FIG. 3 , an example of the optical axis (also referred to as the second optical axis) Ax2 of the first lens 321a is schematically shown by a thin dashed dotted line. The first lens 321a, the second lens 321b, and the third lens 321c are aligned in the −Z direction, which is the first direction, on the second optical axis Ax2. The first lens 321a and the second lens 321b are positioned between the wavelength conversion unit 422 and the wavelength separation filter 31. The third lens 321c is positioned between the wavelength separation filter 31 and the first opening 10a. Each of the one or more lenses 321 is made of, for example, one or more materials selected from the group consisting of glass and resin.

[0055] For example, the excitation light L0 from the light source 20 is reflected by the wavelength separation filter 31, then passes through the second lens 321b and the first lens 321a in this order, and enters the wavelength conversion unit 422. The second lens 321b and the first lens 321a focus the excitation light L0 reflected by the wavelength separation filter 31 onto the wavelength conversion unit 422. For example, a biconvex lens is used for each of the first lens 321a and the second lens 321b. In the example of FIG. 3 , the excitation light L0 passes through the second lens 321b and the first lens 321a in order, thereby gradually reducing the degree of divergence of the excitation light L0. In other words, the size of the cross section perpendicular to the second optical axis Ax2 of the excitation light L0 traveling from the wavelength separation filter 31 to the wavelength conversion unit 422 gradually decreases.

[0056] The wavelength conversion unit 422 emits fluorescence L1 in response to the incident excitation light L0. This fluorescence L1 travels from the wavelength conversion unit 422 at a large divergence angle, passes through the first lens 321a and the second lens 321b, and enters the wavelength separation filter 31. The first lens 321a and the second lens 321b transmit the fluorescence L1 toward the effective surface of the wavelength separation filter 31. The effective surface here refers to the area where the filtering function of the wavelength separation filter 31 can be realized. In the example of FIG. 3 , as the fluorescence L1 passes through the first lens 321a and the second lens 321b in sequence, the degree of divergence of the fluorescence L1 gradually decreases. In other words, the fluorescence L1 traveling from the wavelength conversion unit 422 to the wavelength separation filter 31 gradually decreases in cross-sectional size perpendicular to the second optical axis Ax2. Therefore, the divergence angle of the fluorescence L1 from the wavelength conversion unit 422 is reduced by the first lens 321a and the second lens 321b. This allows a larger amount of fluorescence L1 to be guided to the wavelength separation filter 31 without increasing the size of the wavelength separation filter 31 .

[0057] In the example of FIG. 3 , the size of the cross section of the fluorescence L1 transmitted through the second lens 321b, perpendicular to the second optical axis Ax2, decreases toward the third lens 321c and then increases through a waist portion BW. The waist portion BW is the portion between the second lens 321b and the third lens 321c where the cross section of the fluorescence L1, perpendicular to the second optical axis Ax2, is smallest. As shown in FIG. 3 , the waist portion BW may be located at a position overlapping with the center of the wavelength separation filter 31 in the direction along the second optical axis Ax2 (also referred to as the optical axis direction). In other words, the first lens 321a and the second lens 321b may be designed so that the waist portion BW overlaps with the center of the wavelength separation filter 31 in the optical axis direction.

[0058] The wavelength separation filter 31 transmits the fluorescence L1 toward the first opening 10a. The fluorescence L1 from the wavelength separation filter 31 is transmitted through the third lens 321c, passes through the first opening 10a, and is emitted into the illumination space S1. In the example of Fig. 3, the fluorescence L1 from the wavelength separation filter 31 is transmitted through the third lens 321c, passes through the first opening 10a and a third opening 50a (described later), and is emitted into the illumination space S1.

[0059] Here, for example, the number of lenses 321 located between the wavelength conversion unit 422 and the wavelength separation filter 31 is not limited to two, and may be one, or three or more. The third lens 321c may not be present.

[0060] <1-5. Holding Mechanism> The holding mechanism 60 holds the optical system 30 within the housing 10. As shown in FIG. 3, the holding mechanism 60 includes one or more holding members 61. In the example of FIG. 3, the one or more holding members 61 include a first holding member 61a, a second holding member 61b, a third holding member 61c, and a fourth holding member 61d. The material of the multiple holding members 61 may be the same as that of the housing 10, or a different material from that of the housing 10. The material of the multiple holding members 61 may be, for example, an aluminum alloy, or another material such as a synthetic resin.

[0061] <1-5-1. First Holding Member> The first holding member 61a may function as a lens holder that holds the first lens 321a between itself and the first portion 12 of the housing 10. As shown in FIG. 3, the first holding member 61a is located between the first lens 321a and the second lens 321b. The outer periphery of the first lens 321a may be sandwiched and held between the first portion 12 and the first holding member 61a in the optical axis direction. The outer periphery of the first lens 321a may be the outer periphery of the first lens 321a centered on the second optical axis Ax2. The first holding member 61a has, for example, a cylindrical shape that surrounds the second optical axis Ax2. The inner periphery of the first holding member 61a may have, for example, one or more protrusions for pressing the outer periphery of the first lens 321a against the first portion 12. The inner peripheral portion of the first holding member 61 a may be a portion of the inner peripheral portion of the first holding member 61 a that is located near the second optical axis Ax2. The one or more convex portions may be, for example, a single convex portion having an annular shape centered on the second optical axis Ax2, or two or more convex portions aligned in the circumferential direction centered on the second optical axis Ax2.

[0062] The inner peripheral surface of the first holding member 61a is located closer to the second optical axis Ax2 than the outer peripheral surface of the second lens 321b. The inner peripheral surface of the first holding member 61a may be an inner peripheral surface of the first holding member 61a located closer to the second optical axis Ax2. The outer peripheral surface of the second lens 321b may be an outer peripheral surface centered on the second optical axis Ax2 of the second lens 321b. In the example of FIG. 3 , the outer peripheral surface of the second lens 321b may be an annular side surface connecting a surface of the second lens 321b located on the wavelength conversion unit 422 side and a surface of the second lens 321b located on the wavelength separation filter 31 side.

[0063] The outer peripheral surface of the first holding member 61a may be in contact with the inner peripheral surface of the cylindrical portion 11. The outer peripheral surface of the first holding member 61a may be an outer peripheral surface centered on the second optical axis Ax2 of the first holding member 61a. The outer peripheral surface of the first holding member 61a may be fitted into the inner peripheral surface of the cylindrical portion 11. For example, if a structure is adopted in which the male thread portion on the outer peripheral surface of the first holding member 61a is fitted into the female thread portion on the inner peripheral surface of the cylindrical portion 11, the occurrence of misalignment (also referred to as positional displacement) of the first lens 321a during transportation, use, etc. of the lighting device 1 can be reduced. The outer peripheral surface of the first holding member 61a may be fixed to the inner peripheral surface of the cylindrical portion 11 by adhesive or the like. The outer peripheral surface of the second lens 321b may be in contact with the inner peripheral surface of the cylindrical portion 11. The second lens 321b may be fitted into the inner peripheral surface of the cylindrical portion 11.

[0064] Here, for example, if the first holding member 61a is in contact with the outer periphery of the second lens 321b, the first holding member 61a can function as a spacer that determines the distance between the first lens 321a and the second lens 321b. In other words, if the lens optical system 32 includes the first lens 321a and the second lens 321b, and the lighting device 1 includes the first holding member 61a as a spacer that is sandwiched between the first lens 321a and the second lens 321b, the distance between the first lens 321a and the second lens 321b can be easily set. The outer periphery of the second lens 321b may be the outer periphery of the second lens 321b centered on the second optical axis Ax2.

[0065] <1-5-2. Second Holding Member> The second holding member 61b, together with the first holding member 61a, can function as a lens holder that holds the second lens 321b. As shown in FIG. 3, the second holding member 61b is positioned between the second lens 321b and the wavelength separation filter 31. The second holding member 61b has, for example, a cylindrical shape surrounding the second optical axis Ax2. The inner circumferential surface of the second holding member 61b is positioned closer to the second optical axis Ax2 than the outer circumferential surface of the second lens 321b. The inner circumferential surface of the second holding member 61b may be an inner circumferential surface positioned closer to the second optical axis Ax2 of the second holding member 61b. The outer circumferential surface of the second holding member 61b may be in contact with the inner circumferential surface of the cylindrical portion 11. The outer circumferential surface of the second holding member 61b may be an outer circumferential surface centered on the second optical axis Ax2 of the second holding member 61b. The outer periphery of the second lens 321b may be sandwiched between the first holding member 61a and the second holding member 61b in the optical axis direction. In this case, the edge of the first holding member 61a on the second lens 321b side is in contact with the outer periphery of the surface of the second lens 321b that faces the wavelength conversion unit 422. The edge of the second holding member 61b on the second lens 321b side is in contact with the outer periphery of the surface of the second lens 321b that faces the wavelength separation filter 31.

[0066] An edge portion of the second holding member 61b on the wavelength separation filter 31 side may be in contact with, for example, the outer periphery of the wavelength separation filter 31. In this case, the second holding member 61b can function as a spacer that determines the distance between the second lens 321b and the wavelength separation filter 31. The outer periphery of the wavelength separation filter 31 may be a portion of the outer periphery of the wavelength separation filter 31 that is centered on the second optical axis Ax2. The end face of the second holding member 61b that faces the wavelength separation filter 31 may have a shape that follows the first plate surface 3a that faces the wavelength conversion unit 422 of the wavelength separation filter 31.

[0067] As shown in FIG. 3, the second holding member 61b may have a second introduction opening 61ba. The second introduction opening 61ba is connected to the first introduction opening 10c in a continuous state. The second introduction opening 61ba is an opening that allows the excitation light L0 that has been emitted from the light source 20 and passed through the first introduction opening 10c to pass through and guide the excitation light L0 into the internal space 10is of the housing 10. In the example of FIG. 3, the second introduction opening 61ba penetrates the second holding member 61b along the −X direction, which is the second direction.

[0068] <1-5-3. Third Holding Member> The third holding member 61c, together with the second holding member 61b, can function as a filter holder 60h that holds the wavelength separation filter 31. As shown in FIG. 3, the third holding member 61c is located between the wavelength separation filter 31 and the third lens 321c. The third holding member 61c has, for example, a cylindrical shape that surrounds the second optical axis Ax2. The outer peripheral surface of the third holding member 61c may be in contact with the inner peripheral surface of the cylindrical portion 11. The outer peripheral surface of the third holding member 61c may be a peripheral surface centered on the second optical axis Ax2 of the third holding member 61c. The edge portion of the third holding member 61c on the wavelength separation filter 31 side may be in contact with the outer peripheral portion of the wavelength separation filter 31, for example. In the example of FIG. 3, the edge portion of the third holding member 61c on the wavelength separation filter 31 side is in contact with the outer peripheral portion of the second plate surface 3b of the wavelength separation filter 31. The end face of the third holding member 61c facing the wavelength separation filter 31 may have a shape that follows the second plate surface 3b facing the third lens 321c of the wavelength separation filter 31. The outer periphery of the wavelength separation filter 31 may be sandwiched between the second holding member 61b and the third holding member 61c in the optical axis direction. In this case, the edge of the second holding member 61b facing the wavelength separation filter 31 contacts the outer periphery of the surface of the wavelength separation filter 31 that is located on the wavelength conversion unit 422 side. The edge of the third holding member 61c facing the wavelength separation filter 31 contacts the outer periphery of the surface of the wavelength separation filter 31 that is located on the opposite side from the wavelength conversion unit 422.

[0069] An adhesive may be positioned between the wavelength separation filter 31 and the second holding member 61b. An adhesive may be positioned between the wavelength separation filter 31 and the third holding member 61c. An adhesive may be positioned between the wavelength separation filter 31 and the inner circumferential surface of the cylindrical portion 11. An adhesive may be positioned between the second holding member 61b and the inner circumferential surface of the cylindrical portion 11. An adhesive may be positioned between the third holding member 61c and the inner circumferential surface of the cylindrical portion 11.

[0070] Here, if the edge portion of the third holding member 61c on the third lens 321c side is in contact with the outer periphery of the third lens 321c, the third holding member 61c can function as a spacer that determines the distance between the wavelength separation filter 31 and the third lens 321c. The outer periphery of the third lens 321c may be the outer periphery of the third lens 321c centered on the second optical axis Ax2.

[0071] <1-5-4. Fourth Holding Member> The fourth holding member 61d can function as a lens holder that holds the third lens 321c together with the third holding member 61c. The fourth holding member 61d is located between the third lens 321c and the second member 50. The fourth holding member 61d has, for example, a cylindrical shape that surrounds the second optical axis Ax2. The inner peripheral surface of the fourth holding member 61d is located closer to the second optical axis Ax2 than the outer peripheral surface of the third lens 321c. The inner peripheral surface of the fourth holding member 61d may be an inner peripheral surface that is located closer to the second optical axis Ax2 of the fourth holding member 61d. The outer peripheral surface of the third lens 321c may be an outer peripheral surface centered on the second optical axis Ax2 of the third lens 321c. In the example of Figure 3, the outer peripheral surface of the third lens 321c is an annular side surface that connects the surface of the third lens 321c that is located on the wavelength separation filter 31 side and the surface of the third lens 321c that is located on the first opening 10a side.

[0072] The outer periphery of the third lens 321c may be sandwiched between the third holding member 61c and the fourth holding member 61d in the optical axis direction. In this case, the edge of the third holding member 61c facing the third lens 321c contacts the outer periphery of the surface of the third lens 321c facing the wavelength separation filter 31. The edge of the fourth holding member 61d facing the third lens 321c contacts the outer periphery of the surface of the third lens 321c facing the first opening 10a.

[0073] The outer peripheral surface of the fourth holding member 61d may be in contact with the inner peripheral surface of the cylindrical portion 11. The outer peripheral surface of the fourth holding member 61d may be a surface of the outer periphery centered on the second optical axis Ax2 of the fourth holding member 61d. For example, if a structure is adopted in which the male thread portion on the outer peripheral surface of the fourth holding member 61d is fitted into the female thread portion on the inner peripheral surface of the cylindrical portion 11, the occurrence of misalignment of the third lens 321c during transportation, use, etc. of the lighting device 1 can be reduced. The outer peripheral surface of the fourth holding member 61d may be fixed to the inner peripheral surface of the cylindrical portion 11 by adhesive or the like. The outer peripheral surface of the third lens 321c may be in contact with the inner peripheral surface of the cylindrical portion 11. The third lens 321c may be fitted into the inner peripheral surface of the cylindrical portion 11.

[0074] <1-6. Second Member> The second member 50 is located in a state where it is fixed to the housing 10 from the first opening 10a side. In the example of Fig. 3, the second member 50 is fixed to the first end E1 of the cylindrical portion 11, which is on the opposite side to the second end E2 from which the first portion 12 of the cylindrical portion 11 protrudes inward.

[0075] As shown in FIGS. 1 and 3 , the second member 50 may include, for example, a plate-like portion 51 and a protrusion 52. The plate-like portion 51 has a plate-like shape. In the example of FIG. 3 , the thickness direction of the plate-like portion 51 is along the optical axis direction. The plate-like portion 51 has a surface (also referred to as a fourth surface) 51u located on the housing 10 side. The protrusion 52 is a portion that protrudes from the fourth surface 51u of the plate-like portion 51 toward the wavelength separation filter 31 along the optical axis direction. The protrusion 52 may have, for example, a cylindrical shape. The protrusion 52 is inserted into the internal space 10is along the inner surface of the cylindrical portion 11 and is fixed to the cylindrical portion 11. For example, the protrusion 52 may have a male thread portion fitted into a female thread portion located on the inner periphery of the cylindrical portion 11 on the first end E1 side. The protrusion 52 may be fixed to the cylindrical portion 11 by, for example, adhesion, bonding, or fitting.

[0076] The second member 50 may be in contact with the fourth holding member 61d. In the example of Fig. 3, the plate-like portion 51 of the second member 50 is in contact with the edge portion of the fourth holding member 61d on the second member 50 side. The fourth surface 51u may be in contact with the first end E1.

[0077] The second member 50 has a third opening 50a through which the fluorescence L1 passes. For example, the plate-shaped portion 51 may have the third opening 50a. In the example of FIG. 3 , the third opening 50a of the second member 50 is located on the illumination space S1 side of the first opening 10a of the housing 10. Therefore, the fluorescence L1 passes through the first opening 10a and then the third opening 50a. In the example of FIG. 3 , the third opening 50a penetrates the center of the plate-shaped portion 51 in the optical axis direction. The diameter of the third opening 50a is smaller than, for example, the inner diameter of the fourth holding member 61d. As shown in FIG. 3 , the first inner circumferential surface 51s constituting the third opening 50a of the second member 50 may be inclined with respect to the second optical axis Ax2 such that the area of ​​the cross section perpendicular to the optical axis direction (also referred to as the opening area) increases as the first inner circumferential surface 51s approaches the illumination space S1 in the optical axis direction. In other words, the first inner circumferential surface 51s may be inclined with respect to the central axis of the third opening 50a so as to move away from the central axis as it approaches the illumination space S1.

[0078] The optical system 30 is sandwiched between the second member 50 and the inner surface 10if of the housing 10. In other words, the optical system 30 is sandwiched between the second member 50 and the inner surface 10if of the housing 10. In the example of Fig. 3, the optical system 30 is sandwiched between the first part 12 of the housing 10 and the second member 50. More specifically, the optical system 30 and the multiple holding members 61 are sandwiched between the first part 12 of the housing 10 and the plate-like portion 51 of the second member 50.

[0079] Aluminum alloys or various synthetic resins may be used as the material of the second member 50. The second member 50 may have a structure in which a plurality of components are connected by adhesion, bonding, fitting, fastening, or the like.

[0080] 4 , for example, one or more lenses 321 and wavelength separation filter 31 for constituting the optical system 30, and one or more holding members 61 for constituting the holding mechanism 60 can be inserted into the internal space 10is of the housing 10 through the first opening 10a. Here, for example, the first lens 321a, the first holding member 61a, the second lens 321b, the second holding member 61b, the wavelength separation filter 31, the third holding member 61c, the third lens 321c, and the fourth holding member 61d can be inserted into the internal space 10is of the housing 10 through the first opening 10a in this order. Then, by fixing the second member 50 to the housing 10 from the first opening 10a side, the optical system 30 can be sandwiched between the second member 50 and the inner surface 10if of the housing 10. 3 , the first opening 10a and the second opening 10b are located on opposite sides of the internal space 10is in the housing 10, so that the optical system 30 can be sandwiched between the first part 12 of the housing 10 and the second member 50. This process makes it possible to easily fix the optical system 30 in the internal space 10is of the housing 10.

[0081] Here, the first lens 321a, the first holding member 61a, the second lens 321b, the second holding member 61b, the wavelength separation filter 31, the third holding member 61c, the third lens 321c, and the fourth holding member 61d may or may not be fixed to the housing 10. The first lens 321a, the first holding member 61a, the second lens 321b, the second holding member 61b, the wavelength separation filter 31, the third holding member 61c, the third lens 321c, and the fourth holding member 61d may be fixed to the housing 10 by sandwiching them between the first part 12 of the housing 10 and the second member 50.

[0082] Furthermore, when assembling the lighting device 1, for example, as shown in Figure 4, the light source 20 may be fixed to the housing 10 by inserting the protrusion 22 of the mounting member 200 into the first introduction opening 10c of the housing 10 and fixing the mounting member 200 to the housing 10.

[0083] Furthermore, when assembling the lighting device 1, for example, as shown in FIG. 4 , the first member 40 can be fixed to the housing 10 in a form in which the base portion 41 covers the second opening 10b from the outside Ex1 side of the housing 10. Here, the base portion 41 can be fixed to the housing 10 in a state in which it can be removed toward the outside Ex1 side of the housing 10. In the example of FIG. 4 , the base portion 41 can be fixed to the housing 10 using a plurality of male screw members Sw1 in a state in which it can be removed toward the outside Ex1 side of the housing 10. Here, for example, the base portion 41 can be fastened to the housing 10 by inserting each male screw member Sw1 into a through hole Th1 of the base portion 41 and fitting it into a screw hole Sh1 of the housing 10.

[0084] Here, for example, as shown in FIGS. 2 and 5 , the multiple through holes Th1 may be located at multiple locations centered on the second optical axis Ax2. The multiple locations include a first location where one through hole Th1 is located and two or more locations that are sequentially rotated by a first predetermined angle (also referred to as the first predetermined angle) θ0 around the second optical axis Ax2 using the first location as a reference. In FIGS. 2 and 5 , an example of the second optical axis Ax2 is indicated by a black circle, and an example of the first predetermined angle θ0 is indicated by a thin arc-shaped arrow. Furthermore, for example, as shown in FIG. 6 , the multiple screw holes Sh1 may be located at multiple locations centered on the second optical axis Ax2. The multiple locations include a first location where one screw hole Sh1 is located and two or more locations that are sequentially rotated by the first predetermined angle θ0 around the second optical axis Ax2 using the first location as a reference. In FIG. 6, an example of the second optical axis Ax2 is indicated by a black circle, and an example of the first predetermined angle θ0 is indicated by a thin arc-shaped arrow.

[0085] More specifically, for example, when the first predetermined angle θ0 is 120 degrees, the three through holes Th1 may be located at three locations centered on the second optical axis Ax2. These three locations include a first location where one through hole Th1 is located and two locations that are located sequentially by rotating 120 degrees around the second optical axis Ax2 from the first location. For example, the three screw holes Sh1 may be located at three locations centered on the second optical axis Ax2. These three locations include a first location where one screw hole Sh1 is located and two locations that are located sequentially by rotating 120 degrees around the second optical axis Ax2 from the first location.

[0086] For example, assume that the cross-sectional shape of the second opening 10b is a circle centered on the second optical axis Ax2, the shape of the convex portion 412 is a cylinder or a truncated cone centered on the second optical axis Ax2, and the convex portion 412 is fitted into the second opening 10b. In this case, by rotating the base portion 41 with the convex portion 412 fitted into the second opening 10b, the multiple screw holes Sh1 and the multiple through holes Th1 can be easily aligned.

[0087] <1-8. Replacing the First Member from the Illumination Device> In the illumination device 1 described above, the optical system 30 is sandwiched between the inner surface 10if of the housing 10 and the second member 50 fixed to the housing 10 from the first opening 10a side. In the example of Fig. 3, the optical system 30 is sandwiched between the first part 12 of the housing 10 and the second member 50 fixed to the housing 10 from the first opening 10a side. In addition, the base portion 41 of the first member 40 is positioned in a state covering the second opening 10b from the outside Ex1 side of the housing 10, and is fixed to the housing 10 in a state where it can be removed to the outside Ex1 side of the housing 10.

[0088] Therefore, with the optical system 30 fixed in the internal space 10is of the housing 10, the base portion 41 to which the wavelength conversion unit 422 is fixed can be removed from the housing 10. In other words, with the optical system 30 fixed in the internal space 10is of the housing 10, the first member 40 including the wavelength conversion unit 422 can be removed from the housing 10. For example, as shown in FIG. 7 , by removing the multiple male screw members Sw1 from the multiple screw holes Sh1, the base portion 41 can be removed from the housing 10 toward the outside Ex1 of the housing 10. In other words, the first member 40 can be removed from the housing 10 toward the outside Ex1 of the housing 10. Then, after removing the first member 40 from the housing 10, a new first member 40 can be attached and fixed to the housing 10, as illustrated in FIG. 4 .

[0089] Therefore, the first member 40 can be replaced while the optical system 30 is fixed in the internal space 10is of the housing 10. As a result, the wavelength conversion unit 422 can be replaced while the optical system 30 is fixed in the internal space 10is of the housing 10. In other words, the wavelength conversion unit 422 can be replaced without removing the optical system 30 from the lighting device 1. This allows the lighting device 1 to have a longer life and be easier to handle.

[0090] Here, the new first member 40 after replacement may be a first member 40 in which the entire first member 40 removed from the housing 10 has been replaced, or it may be a first member 40 in which only the phosphor substrate 42 of the first member 40 removed from the housing 10 has been replaced.

[0091] <1-9. Other Configurations> The lens optical system 32 may be an imaging optical system that forms an image of the wavelength conversion unit 422 on a virtual image plane IS1. In the example of FIG. 3, this imaging optical system is composed of a first lens 321a, a second lens 321b, and a third lens 321c. The wavelength conversion unit 422 may have a conjugate relationship with the image plane IS1. The term "conjugate relationship" does not have a strict meaning here. The image plane IS1 can be considered to be the portion of the fluorescence L1 at which the fluorescence L1 is most concentrated (the portion of the fluorescence L1 with the smallest cross-sectional area perpendicular to the second optical axis Ax2) on the third aperture 50a side of the wavelength conversion unit 422. The image plane IS1 may be located at the third aperture 50a, for example. The image plane IS1 may be a flat or curved surface. The fluorescence L1 is collected at the image plane IS1 and emitted through the third aperture 50a into the illumination space S1. Here, the image plane IS1 does not have to be located inside the third aperture 50a. 3, the image plane IS1 may be located at the boundary between the internal space of the third opening 50a and the internal space 10is of the housing 10. Alternatively, the image plane IS1 may be located at a position slightly shifted from this boundary toward the internal space 10is of the housing 10. Alternatively, the image plane IS1 may be located at the boundary between the internal space of the third opening 50a and the illumination space S1, or may be located at a position slightly shifted from this boundary toward the illumination space S1.

[0092] Here, the size of the fluorescence L1 on the surface of the wavelength converting unit 422 is defined as a first size, the size of the fluorescence L1 on the image plane IS1 is defined as a second size, and the size of the third opening 50a is defined as a third size. In this illumination device 1, the imaging magnification of the lens optical system 32 may be set to be equal to or less than the value obtained by dividing the third size by the first size. The first size may be, for example, the size of an area of ​​the surface of the wavelength converting unit 422 facing the lens optical system 32 that is irradiated with the excitation light L0. The third size may be the minimum value of the opening area of ​​the third opening 50a as viewed along the optical axis direction. The imaging magnification may be the value obtained by dividing the second size by the first size.

[0093] 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 second optical axis Ax2. ２The light intensity distribution on the cross section perpendicular to the second optical axis Ax2 may be defined by a contour line having a light intensity of 1 / 1. Here, "e" is called the Napier's constant. In other words, the light rays on both outer edges of the fluorescence L1 shown in FIG. 3 are defined by a contour line having a light intensity of 1 / 1. ２ The light in the area outside the area surrounded by the contour lines (i.e., the light rays on both outer edges) may be regarded as noise light.

[0094] If the imaging magnification is equal to or less than the value obtained by dividing the third size by the first size, the size of the fluorescence L1 on the image plane IS1 (second size) can be made equal to or less than the size of the third opening 50a (third size). This reduces the possibility that the fluorescence L1 will be incident on the peripheral portion of the third opening 50a in the housing 10. This reduces unnecessary reflected and scattered light leaking from the third opening 50a.

[0095] The imaging magnification of the lens optical system 32 may be set to a value such that the magnitude of the fluorescence L1 passing through the third opening 50a is smaller than that of the third opening 50a, thereby further reducing the reflected and scattered light.

[0096] Here, the spread angle of the fluorescence L1 from the wavelength conversion unit 422 toward the first lens 321a is defined as the first spread angle, and the spread angle of the fluorescence L1 in the illumination space S1 is defined as the second spread angle. In FIG. 3 , an example of the second spread angle θ2 is indicated by a thin arc-shaped arrow. The first spread angle can be considered to be the spread angle of the fluorescence L1 immediately before the lens optical system 32, and the second spread angle θ2 can be considered to be the spread angle of the fluorescence L1 immediately after the image plane IS1. The lens optical system 32 may be designed under the condition that the second spread angle θ2 is smaller than the first spread angle. As a specific example of the second spread angle θ2, the orientation angle (e.g., half-value angle) of the fluorescence L1 in the illumination space S1 is approximately 60 degrees or less. The orientation angle of the illumination device 1 may be, for example, less than 45 degrees, less than 30 degrees, or less than 15 degrees. As a result, for example, when a plurality of lighting devices 1 are positioned at regular intervals in the lighting space S1, the glare of the lighting devices 1 that enters the field of view in the lighting space S1 is reduced, which can increase the comfort of the lighting space S1.

[0097] 2. Other Embodiments The present disclosure is not limited to the first embodiment described above, and various modifications and improvements can be made without departing from the gist of the present disclosure.

[0098] 2-1. Second Embodiment In the first embodiment, for example, as shown in FIG. 8 , the lighting device 1 may further include one or more heat dissipation members 70. FIG. 8 is a front view schematically illustrating an example of the appearance of the lighting device 1 according to the second embodiment. The example of the lighting device 1 according to the second embodiment shown in FIG. 8 is based on the lighting device 1 according to the first embodiment and further includes one or more heat dissipation members 70. The heat dissipation members 70 are members that increase the dissipation of heat from the lighting device 1 to the external space. Examples of materials that can be used for the heat dissipation members 70 include metal materials with high thermal conductivity, such as Cu, Al, Mg, Au, Ag, Fe, Cr, Co, Be, Mo, W, and alloys.

[0099] The one or more heat dissipation members 70 include, for example, a first heat dissipation member 70a and a second heat dissipation member 70b. Each of the one or more heat dissipation members 70 has a plurality of protrusions 72. The protrusions 72 may be thin plate-like fins or elongated rod-like pins. The presence of the protrusions 72 may increase heat dissipation from the heat dissipation member 70 to the external space. Each of the one or more heat dissipation members 70 may include a plate-like base 71 and a plurality of protrusions 72 each positioned to protrude from the base 71. In the example of FIG. 8 , the first heat dissipation member 70a includes a plate-like first base 71a and a plurality of first protrusions 72a each positioned to protrude from the first base 71a. The second heat dissipation member 70b includes a plate-like second base 71b and a plurality of second protrusions 72b each positioned to protrude from the second base 71b.

[0100] For example, when the first heat dissipation member 70a is fixed to the base portion 41 of the first member 40, the first heat dissipation member 70a can increase the rate at which heat dissipates from the wavelength conversion portion 422 via the base portion 41 or the like. This can reduce the degree to which the wavelength conversion portion 422 is deteriorated by heat. When the first heat dissipation member 70a is fixed to the base portion 41, the first heat dissipation member 70a may be in contact with the base portion 41. Here, for example, the first heat dissipation member 70a and the base portion 41 may sandwich one or more members. For example, plate-shaped members may be used as the one or more members. For example, metal materials with high thermal conductivity, such as Cu, Al, Mg, Au, Ag, Fe, Cr, Co, Be, Mo, W, or alloys, may be used as the material for the one or more members.

[0101] Here, if the first heat dissipation member 70a is fixed to the base portion 41 in a state in which it can be removed from the base portion 41, then after the first member 40 is removed from the housing 10, when a new first member 40 is attached and fixed to the housing 10, the first heat dissipation member 70a can be easily reused.

[0102] Here, for example, as shown in FIG. 8 , the first heat dissipation member 70a may be fixed to the base portion 41 with the first base portion 71a in contact with a surface (also referred to as a fifth surface) 411u of the main body 411 of the base portion 41 that is opposite to the first surface 411b. For example, the first base portion 71a may be fastened to the base portion 41 by inserting a male screw member Sw2 into a through hole Th2 of the first base portion 71a and fitting it into a screw hole Sh2 of the base portion 41. More specifically, the first base portion 71a may be fastened to the base portion 41 by multiple pairs of the through hole Th2, the male screw member Sw2, and the screw hole Sh2. In the example of FIG. 8 , the first base portion 71a has three through holes Th2 that each penetrate in the −Z direction as the first direction as the multiple through holes Th2. The main body 411 of the base 41 has, as the plurality of screw holes Sh2, three screw holes Sh2 that are recessed in the −Z direction, which is the first direction, on the fifth surface 411u side.

[0103] 9 is a diagram schematically illustrating an example of how one or more heat dissipation members 70 are removed from the lighting device 1 according to the second embodiment. As shown in Fig. 9, the first heat dissipation member 70a can be removed from the base portion 41 by removing the multiple male screw members Sw2 from the multiple screw holes Sh2. In Figs. 8 and 9, hidden lines that depict examples of the outer edges of some components are schematically illustrated by thin dashed lines.

[0104] For example, when the second heat dissipation member 70b is fixed to the first holding portion 21 of the mounting member 200, the second heat dissipation member 70b can increase the rate at which heat dissipates from the light source 20 via the mounting member 200. This can reduce the degree to which the light source 20 is deteriorated by heat.

[0105] Here, if the second heat dissipation member 70b is in a state where it can be removed from the mounting member 200 and is fixed to the mounting member 200, then after the mounting member 200 is removed from the housing 10, when a new mounting member 200 is attached and fixed to the housing 10, the second heat dissipation member 70b can be easily reused.

[0106] Here, for example, as shown in FIG. 8 , the second heat dissipation member 70b may be fixed to the mounting member 200 with the second base 71b in contact with the surface of the first holding portion 21 of the mounting member 200 opposite the housing 10. For example, the second base 71b may be fastened to the mounting member 200 by inserting a male screw member Sw3 into a screw hole Sh3 of the mounting member 200. More specifically, the second base 71b may be fastened to the mounting member 200 by multiple pairs of the through hole Th3, the male screw member Sw3, and the screw hole Sh3. In the example of FIG. 8 , the second base 71b has three through holes Th3 as the multiple through holes Th3, each penetrating in the −X direction as the second direction. The first holding portion 21 of the mounting member 200 has, as the multiple screw holes Sh3, three screw holes Sh3 that are recessed in the −X direction, which is the second direction, on the side opposite to the housing 10.

[0107] According to this configuration, as shown in FIG. 9, the second heat dissipation member 70b can be removed from the attachment member 200 by removing the plurality of male screw members Sw3 from the plurality of screw holes Sh3.

[0108] Here, the lighting device 1 may include either the first heat dissipation member 70a or the second heat dissipation member 70b, or may include both the first heat dissipation member 70a and the second heat dissipation member 70b.

[0109] Here, for example, the first heat dissipation member 70a may be directly fixed to the housing 10. In this case, for example, the base portion 41 may be fixed to the housing 10 by being sandwiched between the first heat dissipation member 70a and the housing 10. Here, for example, the first heat dissipation member 70a may be fixed to the housing 10 in a state in which it can be removed from the housing 10. As a result, the first heat dissipation member 70a may be fixed to the base portion 41 in a state in which it can be removed from the base portion 41. The first heat dissipation member 70a may be fixed to the housing 10 in various ways, for example, by fastening or bonding. Fastening may be achieved, for example, by fitting a male-threaded member into a screw hole having a female thread on the inner circumferential surface. Bonding may be achieved, for example, by using an adhesive having low adhesive strength. This adhesive may be achieved, for example, by using a curable adhesive resin such as an epoxy resin or a silicone resin. The first heat dissipation member 70a may have a structure including, for example, a third predetermined portion that is directly fixed to the housing 10. The third predetermined portion may include one or more protrusions and / or one or more flanges. The base portion 41 may include, for example, a fourth predetermined portion having a shape in which various members and / or portions for directly fixing the first heat dissipation member 70a to the housing 10 can be arranged. The fourth predetermined portion may be, for example, a portion with a through-hole and / or a notched portion.

[0110] FIG. 10 is a front view schematically illustrating the appearance of another example of the lighting device 1 according to the second embodiment. As shown in FIG. 10 , for example, the base 41 may include multiple protrusions (also referred to as third protrusions) 73a. For example, each of the multiple third protrusions 73a may be a thin plate-like fin or a thin rod-like pin. The multiple third protrusions 73a may function as heat dissipation units that increase the rate at which heat dissipates from the base 41 to the external space. This increases the rate at which heat dissipates from the wavelength conversion unit 422. As a result, the degree to which the wavelength conversion unit 422 is deteriorated by heat may be reduced. In the example of FIG. 10 , each of the multiple third protrusions 73a protrudes from the fifth surface 411u of the main body 411 of the base 41 toward the side opposite the housing 10. Here, by adopting a configuration in which the base 41 includes multiple third protrusions 73a, the rate at which heat dissipates from the wavelength conversion unit 422 can be increased with a simple configuration. As a result, the life of the lighting device 1 can be easily extended.

[0111] Here, for example, the mounting member 200 may include multiple protrusions (also referred to as fourth protrusions) 73b. More specifically, the first holding member 21 may include multiple fourth protrusions 73b. For example, each of the multiple fourth protrusions 73b may be a thin plate-like fin or a thin rod-like pin. The multiple fourth protrusions 73b may function as a heat dissipation portion that increases the rate at which heat dissipates from the first holding member 21 to the external space. This increases the rate at which heat dissipates from the light source 20. As a result, the degree to which the light source 20 is deteriorated by heat may be reduced. In the example of FIG. 10 , the multiple fourth protrusions 73b protrude from the surface of the first holding member 21 opposite the housing 10 toward the opposite side from the housing 10. Here, by adopting a configuration in which the mounting member 20 includes multiple fourth protrusions 73b, the rate at which heat dissipates from the light source 20 can be increased with a simple configuration. As a result, the life of the lighting device 1 can be easily extended.

[0112] 2-2. Third Embodiment In each of the above embodiments, for example, as shown in FIGS. 11 to 14 , the base unit 41 may be configured to be fixed to the housing 10 in a state where it can be removed to the outside Ex1 at two or more angles obtained by rotation about the imaginary rotation axis Ax3 passing through the second opening 10b. In other words, the base unit 41 may be configured to be fixed to the housing 10 in a state where it can be removed to the outside Ex1 at two or more angles obtained by rotation about the imaginary rotation axis Ax3 passing through the second opening 10b when the base unit 41 is released from the housing 10. The center P0 of the region A0 of the wavelength conversion unit 422 irradiated with the excitation light L0 may be located at a position offset from the imaginary rotation axis Ax3. Here, the region A0 may be circular or may have another shape, such as an ellipse. If the region A0 is circular or elliptical, the center P0 may be the center point of the region A0. If the region A0 has another shape, the center P0 may be the center of gravity of the region A0.

[0113] According to this configuration, in the lighting device 1, after the base unit 41 is released from the housing 10, the base unit 41 can be rotated around the virtual rotation axis Ax3 and then fixed to the housing 10. This makes it possible to change the area A0 of the wavelength conversion unit 422 onto which the excitation light L0 is irradiated. As a result, deterioration of the wavelength conversion unit 422 can be reduced. This allows the life of the lighting device 1 to be extended.

[0114] FIG. 11 is a plan view schematically illustrating the appearance of an example of an illumination device 1 according to the third embodiment. FIG. 12 is a cross-sectional view schematically illustrating the first member 40 and the vicinity of the first member 40 in the cross-section of the example of the illumination device 1 according to the third embodiment. FIG. 13 is a bottom view schematically illustrating an example of the configuration of the first member 40 of the illumination device 1 according to the third embodiment. FIG. 14 is a diagram schematically illustrating an example of a state in which the base 41 is released from the housing 10 in the illumination device 1 according to the third embodiment. In FIGS. 11 and 13 , examples of the second optical axis Ax2 and the virtual rotation axis Ax3 are indicated by black circles. In FIG. 12 , examples of the second optical axis Ax2 and the virtual rotation axis Ax3 are indicated by thin dashed lines, an example of the outer edge of the excitation light L0 is indicated by a thin broken line, and an example of the outer edge of the fluorescence L1 is indicated by a thin two-dot chain line. In FIG. 13, an example of the outer edge of the area A0 of the wavelength conversion section 422 that is irradiated with the excitation light L0 is shown by a circle drawn with a dashed line.

[0115] 11 to 14 has a configuration in which the position of the first member 40 is shifted in a direction perpendicular to the second optical axis Ax2, based on the illumination device 1 according to the first embodiment. In the examples of Figures 11 to 14, the illumination device 1 according to the first embodiment has a configuration in which the position of the first member 40 and the portion of the second opening 10b on the first member 40 side are translated in the -X direction, which is a direction perpendicular to the second optical axis Ax2.

[0116] In the examples of Figures 11 to 14, as shown in Figure 14, the base portion 41 can be released from the housing 10 by removing the multiple male screw members Sw1 from the multiple screw holes Sh1 and the multiple through holes Th1.

[0117] In the examples of FIGS. 11 to 13 , the multiple through holes Th1 are located at multiple locations centered on a virtual rotation axis Ax3 that is offset from the second optical axis Ax2 in the −X direction. These multiple locations include a first location where one through hole Th1 is located and two or more locations that are sequentially reached by rotating the first location around the virtual rotation axis Ax3 by a first predetermined angle θ0. The multiple screw holes Sh1 are located at multiple locations centered on the virtual rotation axis Ax3. These multiple locations include a first location where one screw hole Sh1 is located and two or more locations that are sequentially reached by rotating the first location around the virtual rotation axis Ax3 by a first predetermined angle θ0. In FIGS. 11 and 13 , an example of the first predetermined angle θ0 is indicated by a thin, arc-shaped arrow. More specifically, for example, when the first predetermined angle θ0 is 120 degrees, three through holes Th1 may be located at three locations centered on the virtual rotation axis Ax3. The three locations include a first location where one through hole Th1 is located and two locations that are located sequentially by rotating 120 degrees around the virtual rotation axis Ax3 using the first location as a reference. Alternatively, three screw holes Sh1 may be located at three locations that are located at the center of the virtual rotation axis Ax3. The three locations include a first location where one screw hole Sh1 is located and two locations that are located sequentially by rotating 120 degrees around the virtual rotation axis Ax3 using the first location as a reference.

[0118] 11 to 13, the imaginary rotation axis Ax3 passes through the center of the portion of the second opening 10b where the convex portion 412 is fitted. Here, for example, assume that the cross-sectional shape of the portion of the second opening 10b where the convex portion 412 is fitted is circular, with the imaginary rotation axis Ax3 at its center, and the shape of the convex portion 412 is cylindrical, with the imaginary rotation axis Ax3 at its center. In this case, if the base portion 41 is released from the housing 10, for example, the base portion 41 can be rotated with the convex portion 412 fitted into the second opening 10b. This allows the combination of the multiple screw holes Sh1 and the multiple through holes Th1, which are aligned with each other, to be changed. Then, for each pair of the screw hole Sh1 and the through hole Th1, the male screw member Sw1 can be inserted through the through hole Th1 and fitted into the screw hole Sh1, thereby fixing the base portion 41 to the housing 10. Therefore, the base portion 41 can be fixed to the housing 10 at two or more different angles rotated about the virtual rotation axis Ax3. For example, when the above-described first predetermined angle θ0 is 120 degrees, there are three combinations of three screw holes Sh1 and three through holes Th1. Therefore, the base portion 41 can be fixed to the housing 10 at three different angles rotated about the virtual rotation axis Ax3. Here, the first predetermined angle θ0 may be any number obtained by dividing 360 degrees by a natural number greater than or equal to two. In other words, the respective numbers of the multiple screw holes Sh1 and the multiple through holes Th1 are not limited to three and may be any natural number greater than or equal to two.

[0119] This structure allows the base unit 41 to be removably fixed to the housing 10 at two or more rotation angles around the virtual rotation axis Ax3 that passes through the second opening 10b. For example, after the base unit 41 is released from the housing 10, the base unit 41 can be rotated around the virtual rotation axis Ax3 through an angle that is n times the first predetermined angle θ0 (n is a natural number), and then fixed to the housing 10. This allows the area A0 irradiated with the excitation light L0 in the wavelength conversion unit 422 to be changed. As a result, deterioration of the wavelength conversion unit 422 can be reduced. This allows the life of the lighting device 1 to be extended.

[0120] Here, the virtual rotation axis Ax3 does not have to intersect with the region A0. In this case, a design can be realized in which, by rotating the base unit 41 around the virtual rotation axis Ax3, the region A0 irradiated with the excitation light L0 in the wavelength conversion unit 422 can be changed from a first region to a second region that does not overlap with the first region. This reduces deterioration of the wavelength conversion unit 422, thereby extending the life of the illumination device 1. Here, for example, if the region A0 is circular, the distance D0 between the second optical axis Ax2 and the virtual rotation axis Ax3 may be greater than half the diameter R0 of the region A0. The distance D0 may be the distance by which the virtual rotation axis Ax3 is offset from the second optical axis Ax2 in a direction perpendicular to the second optical axis Ax2. In the examples of FIGS. 11 to 13 , the distance D0 is the distance by which the virtual rotation axis Ax3 is offset from the second optical axis Ax2 in the −X direction, which serves as the second direction.

[0121] Here, the position of the virtual rotation axis Ax3 is not limited to a position shifted in the −X direction from the second optical axis Ax2, and may be a position shifted from the second optical axis Ax2 in any direction perpendicular to the second optical axis Ax2. The virtual rotation axis Ax3 does not have to be parallel to the second optical axis Ax2, and may be slightly tilted with respect to the second optical axis Ax2.

[0122] 15 , for example, the wavelength separation filter 31 and the first opening 10a may be arranged in this order in the first direction, and the light source 20, the wavelength separation filter 31, and the wavelength conversion unit 422 may be arranged in this order in a second direction intersecting the first direction. The wavelength separation filter 31 may transmit excitation light L0 from the light source 20 toward the wavelength conversion unit 422, and reflect fluorescence L1 from the wavelength conversion unit 422 toward the first opening 10a. If this configuration is adopted, the size of the lighting device 1 in the first direction can be reduced.

[0123] Fig. 15 is a cross-sectional view schematically illustrating an example of the configuration of an illumination device 1 according to a fourth embodiment. The example of the illumination device 1 according to the fourth embodiment shown in Fig. 15 is based on the illumination device 1 according to the first embodiment shown in Fig. 3. This example of the illumination device 1 according to the fourth embodiment has a configuration in which the shape of the housing 10 is changed from an I-shape to an L-shape, and the arrangement of one or more lenses 321 and wavelength separation filters 31 in the optical system 30, and one or more holding members 61 in the holding mechanism 60, is changed in the internal space 10is of the housing 10.

[0124] Here, as shown in FIG. 15, an object having a cylindrical shape bent into an L shape (also called an L-shaped cylinder) is applied to the housing 10.

[0125] In the example of FIG. 15 , the cylindrical portion 11 of the housing 10 has a shape in which a portion having a hollow space penetrating along the −X direction (the second direction) and a portion having a hollow space penetrating along the −Z direction (the first direction) are connected. In other words, the cylindrical portion 11 has a longitudinal direction bent in an L-shape. The cylindrical portion 11 has a first end E1 and a second end E2 at both ends of this longitudinal direction. More specifically, the first end E1 is located at the end of the cylindrical portion 11 on the −Z direction (the first direction) side. The second end E2 is located at the end of the cylindrical portion 11 on the −X direction (the second direction) side. As with the first embodiment, the first opening 10a opens in the −Z direction (the first direction) at the end of the housing 10 on the −Z direction (the first direction). The second opening 10b is a hole that penetrates in the −X direction (the second direction) in the first portion 12 that protrudes inward from the second end E2 of the cylindrical portion 11. In other words, the second opening 10b opens in the −X direction (the second direction) at the end of the housing 10 that faces the −X direction (the second direction).

[0126] The wavelength separation filter 31 is located between the light source 20 and the wavelength conversion unit 422. In the example of Fig. 15, the light source 20, the wavelength separation filter 31, and the wavelength conversion unit 422 are arranged in this order in the -X direction, which is the second direction. For the wavelength separation filter 31, for example, by appropriately setting the thicknesses of the multiple dielectric thin films that make up the dielectric multilayer film 312, it is possible to achieve a spectral transmittance in the dielectric multilayer film 312 that transmits the excitation light L0 and reflects the fluorescence L1.

[0127] The first lens 321a and the second lens 321b are located between the wavelength conversion unit 422 and the wavelength separation filter 31. In the example of Fig. 15, the wavelength separation filter 31, the second lens 321b, the first lens 321a, and the wavelength conversion unit 422 are arranged in this order in the -X direction as the second direction.

[0128] The third lens 321c is located between the wavelength separation filter 31 and the first opening 10a. In the example of Fig. 15, the wavelength separation filter 31, the third lens 321c, and the first opening 10a are arranged in this order in the -Z direction as the first direction.

[0129] In the example of Figure 15, the one or more holding members 61 of the holding mechanism 60 include a first holding member 61a, a second holding member 61b, a third holding member 61c, a fourth holding member 61d, and a fifth holding member 61e. Here, the outer periphery of the first lens 321a is sandwiched between the first portion 12 and the first holding member 61a in the -X direction as the second direction. The outer periphery of the second lens 321b is sandwiched between the first holding member 61a and the fifth holding member 61e in the -X direction as the second direction. The second holding member 61b is located between the fifth holding member 61e and the wavelength separation filter 31. The third holding member 61c is sandwiched between the wavelength separation filter 31 and a portion of the inner surface 10if of the housing 10 facing the -X direction as the second direction. The outer periphery of the third lens 321c is sandwiched between the second holding member 61b and the fourth holding member 61d in the −Z direction as the first direction. The second member 50, which is fixed to the housing 10 from the first opening 10a side, sandwiches the optical system 30 between itself and the inner surface 10if of the housing 10. In other words, the optical system 30 is sandwiched between the second member 50 and the inner surface 10if of the housing 10. In the example of FIG. 15 , the wavelength separation filter 31 and the third lens 321c of the optical system 30 are sandwiched between the second member 50 and a portion of the inner surface 10if of the housing 10 facing the −Z direction as the first direction.

[0130] 15 , the base 41 is positioned in a state where it covers the second end E2, the first portion 12, and the second opening 10b in the +X direction opposite to the −X direction as the second direction. The base 41 is fixed to the housing 10 in a state where it can be removed from the portion of the housing 10 on the second end E2 side in the −X direction as the second direction.

[0131] When assembling the lighting device 1 having such a configuration, the first lens 321a, the first holding member 61a, the second lens 321b, the fifth holding member 61e, the third holding member 61c, the wavelength separation filter 31, the second holding member 61b, the third lens 321c, and the fourth holding member 61d can be inserted into the internal space 10is of the housing 10 through the first opening 10a in this order. Then, by fixing the second member 50 to the housing 10 from the first opening 10a side, the optical system 30 can be sandwiched between the second member 50 and the inner surface 10if of the housing 10. This process makes it possible to easily fix the optical system 30 in the internal space 10is of the housing 10.

[0132] Furthermore, in the lighting device 1, the base unit 41 to which the wavelength conversion unit 422 is fixed can be removed from the housing 10 while the optical system 30 is fixed in the internal space 10is of the housing 10. In other words, while the optical system 30 is fixed in the internal space 10is of the housing 10, the first member 40 including the wavelength conversion unit 422 can be removed from the housing 10 toward the outside Ex1. Then, after removing the first member 40 from the housing 10, a new first member 40 can be attached and fixed to the housing 10. Thus, the first member 40 can be replaced while the optical system 30 is fixed in the internal space 10is of the housing 10. As a result, the wavelength conversion unit 422 can be replaced while the optical system 30 is fixed in the internal space 10is of the housing 10. In other words, the wavelength conversion unit 422 can be replaced without removing the optical system 30 from the lighting device 1. This allows for a longer life and easier handling of the lighting device 1.

[0133] 16 and 17 , the lighting device 1 may include an annular member (also referred to as an annular spacer) 80 located between the second surface 12u of the first portion 12 facing the exterior Ex1 and the base portion 41. In other words, the annular spacer 80 may be sandwiched between the second surface 12u of the first portion 12 of the housing 10 and the base portion 41. More specifically, the annular spacer 80 may be sandwiched between the second surface 12u and the main body portion 411 of the base portion 41. With this configuration, the presence of the annular spacer 80 can separate the housing 10 from the base portion 41 in the direction in which the second opening 10b is open in the first portion 12. Therefore, even if the thickness of the wavelength conversion section 422 varies during manufacturing, by using an annular spacer 80 having a thickness corresponding to the thickness of the wavelength conversion section 422, it is possible to easily align the surface of the wavelength conversion section 422 that is exposed to the internal space 10is.

[0134] FIG. 16 is a front view schematically illustrating the appearance of a lighting device 1 according to another first example. FIG. 17 is a cross-sectional view schematically illustrating an example of a cross section of the lighting device 1 according to another first example, taken along line III-III in FIG. 2 . The lighting device 1 according to another first example shown in FIGS. 16 and 17 is based on the lighting device 1 according to the first embodiment and further includes an annular spacer 80. In the examples of FIGS. 16 and 17 , the annular spacer 80 has a plate-like shape and includes a hole 80h penetrating the annular spacer 80. The annular spacer 80 may be a thin member having a thickness thinner than the first portion 12 and the main body 411 of the base 41. The thickness direction of the annular spacer 80 is the direction along which the first portion 12 of the housing 10 and the main body 411 of the base 41 are spaced apart. The hole 80h penetrates the annular spacer 80 along the direction along which the first portion 12 of the housing 10 and the main body 411 of the base 41 are spaced apart. The protrusion 412 of the base portion 41 may fit into or be inserted through the hole 80h. The annular spacer 80 may be located not only between the second surface 12u of the first portion 12 on the exterior Ex1 side and the base portion 41, but also between the second end E2 of the housing 10 and the base portion 41. The annular spacer 80 may have a shape that does not interfere with the male screw member Sw1, such as by having a plurality of through holes through which the male screw members Sw1 are respectively inserted. For example, when viewed from above, the annular spacer 80 may have a circular ring shape, a rectangular ring shape, or a C-shaped shape in which a portion of the circumferential direction around the hole 80h is not connected.

[0135] Here, instead of including the annular spacer 80, the lighting device 1 may have a configuration in which the distance between the housing 10 and the base portion 41 in the direction in which the second opening 10b opens in the first portion 12 can be adjusted by adjusting the amount of threading of the multiple male screw members Sw1 into the multiple screw holes Sh1. For example, instead of including the annular spacer 80, the lighting device 1 may have a female thread portion on the inner surface of each of the multiple through holes Th1 in the base portion 41, into which the male screw members Sw1 are fitted. In this case, the distance between the housing 10 and the base portion 41 in the direction in which the second opening 10b opens in the first portion 12 can be appropriately adjusted by adjusting the amount of threading of the multiple male screw members Sw1 into the multiple through holes Th1 and the multiple screw holes Sh1, each of which has a female thread portion. Even with this configuration, even if the thickness of the wavelength conversion portion 422 varies during manufacturing, the surface of the wavelength conversion portion 422 that is exposed to the internal space 10is can be aligned.

[0136] 3-2. Another Example of the Illumination Device In each of the above embodiments, the second member 50 may be located in the internal space 10is of the housing 10, as shown in FIG. 18 , as long as the second member 50 sandwiches the optical system 30 between itself and the inner surface 10if of the housing 10 and is fixed to the housing 10 from the first opening 10a side. FIG. 18 is a cross-sectional view schematically illustrating an example of a cross section of an illumination device 1 according to another example of the second embodiment, taken along the line III-III in FIG. 2 . The illumination device 1 according to the another example of the second embodiment shown in FIG. 18 is based on the illumination device 1 according to the first embodiment. The illumination device 1 according to the another example of the second embodiment has a structure in which one or more holding members 61 do not include the fourth holding member 61d, and the second member 50 functions as a lens holder that holds the third lens 321c together with the third holding member 61c, instead of the fourth holding member 61d.

[0137] 18 , the protrusion 52 of the second member 50 has a cylindrical shape surrounding the second optical axis Ax2. The inner peripheral surface of the second member 50 is located closer to the second optical axis Ax2 than the outer peripheral surface of the third lens 321c. The peripheral edge of the third lens 321c is sandwiched between the third holding member 61c and the protrusion 52 of the second member 50 in the optical axis direction. In other words, the edge of the third holding member 61c on the third lens 321c side is in contact with the peripheral edge of the surface of the third lens 321c facing the wavelength separation filter 31, and the edge of the protrusion 52 of the second member 50 on the third lens 321c side is in contact with the peripheral edge of the surface of the third lens 321c facing the first opening 10a.

[0138] In the example of FIG. 18 , the plate-shaped portion 51 of the second member 50 is located in the internal space 10is of the housing. The outer peripheral surfaces of either or both of the plate-shaped portion 51 and the protruding portion 52 may be fixed to the cylindrical portion 11 of the housing 10. For example, the outer peripheral surfaces of either or both of the plate-shaped portion 51 and the protruding portion 52 may have a male thread portion fitted into a female thread portion located on the inner peripheral portion of the cylindrical portion 11 on the first end E1 side. Either or both of the plate-shaped portion 51 and the protruding portion 52 may be fixed to the cylindrical portion 11 by, for example, adhesive bonding, joining, or fitting. With this configuration, the optical system 30 is sandwiched between the second member 50 and the inner surface 10if of the housing 10. In the example of FIG. 18 , the optical system 30 is sandwiched between the first portion 12 of the housing 10 and the second member 50. More specifically, the optical system 30 and the holding mechanism 60 are sandwiched between the first part 12 of the housing 10 and the plate-like portion 51 of the second member 50 .

[0139] Here, the plate-like portion 51 of the second member 50 may be located closer to the wavelength separation filter 31 than the first opening 10a, or may be located at the first opening 10a. The fluorescence L1 may pass through the third opening 50a of the second member 50 and then pass through the first opening 10a of the housing 10, or may pass through the third opening 50a of the second member 50 while passing through the first opening 10a of the housing 10.

[0140] 3-3. Another Third Example of the Lighting Device In each of the above-described embodiments, for example, as shown in Fig. 19, the base portion 41 does not have to have the convex portion 412. Fig. 19 is a cross-sectional view schematically illustrating an example of a cross section of the lighting device 1 according to another third example, taken at a position corresponding to line III-III in Fig. 2. The lighting device 1 according to the another third example shown in Fig. 19 is based on the lighting device 1 according to the above-described first embodiment, does not include the convex portion 412, has the phosphor substrate 42 fixed on the main body portion 411, and has a configuration in which the thickness of the first portion 12 is reduced.

[0141] Even with this configuration, as in the above-described embodiments, the first member 40 can be replaced while the optical system 30 is fixed in the internal space 10is of the housing 10. As a result, the wavelength conversion unit 422 can be replaced while the optical system 30 is fixed in the internal space 10is of the housing 10. In other words, the wavelength conversion unit 422 can be replaced without removing the optical system 30 from the lighting device 1. This allows for a longer life and easier handling of the lighting device 1.

[0142] <3-4. Fourth Example of Illumination Device> In each of the above embodiments, for example, in the illumination device 1, the housing 10 and the base unit 41 may include a mechanism (also referred to as an attachment mechanism) 90 that fixes the base unit 41 to the housing 10 in a state where the base unit 41 can be removed to the outside Ex1 of the housing 10. This makes it easy to remove and attach the base unit 41 to the housing 10. As a result, the wavelength conversion unit 422 can be easily replaced without removing the optical system 30 from the illumination device 1.

[0143] As the attachment mechanism 90, for example, as shown in Figure 20 or 23, a mechanism is adopted in which one or more second parts of the base part 41 are hooked onto one or more first parts of the housing 10, thereby fixing the base part 41 to the housing 10 in a state in which it can be removed to the outside Ex1 of the housing 10.

[0144] <3-4-1. Various Examples of Attachment Mechanisms> Fig. 20 is a cross-sectional view schematically showing the configuration of an example of an attachment mechanism 90 in a lighting device 1 according to a fourth other example. Fig. 21 is a cross-sectional view schematically showing an example of a state in the middle of removing the first member 40 from the housing 10 in a lighting device 1 having the attachment mechanism 90 according to an example. Fig. 22 is a cross-sectional view schematically showing an example of a state after the first member 40 has been removed from the housing 10 in a lighting device 1 having the attachment mechanism 90 according to an example.

[0145] 20 , the housing 10 has, for example, one or more convex portions 91 as one or more first portions of the attachment mechanism 90. The base portion 41 has, for example, a plurality of elastic portions 92 as one or more second portions of the attachment mechanism 90. In FIGS. 20 to 22 , two convex portions 91 and two elastic portions 92 are schematically depicted as a specific example.

[0146] The one or more convex portions 91 are located on the outer circumferential portion 11o of the cylindrical portion 11. The one or more convex portions 91 can be realized by providing one or more recessed portions, convex portions, and stepped portions on the outer circumferential portion 11o of the cylindrical portion 11. The one or more convex portions 91 may be multiple convex portions 91 located at multiple different locations in the circumferential direction on the outer circumferential portion 11o of the cylindrical portion 11, or may be a single annular convex portion 91 located along the circumferential direction on the outer circumferential portion 11o of the cylindrical portion 11.

[0147] Each of the multiple elastic portions 92 includes, for example, a fixed portion 921 fixed to the main body portion 411 of the base portion 41 and a protruding portion 922 protruding from the main body portion 411 along the outer periphery 11o of the tubular portion 11. The fixed portion 921 may be fixed to, for example, a side surface 411s of the main body portion 411. The side surface 411s may be located on the outer periphery of the main body portion 411 and may be a surface connecting the first surface 411b and the fifth surface 411u. The multiple fixed portions 921 are fixed to, for example, multiple different locations in the circumferential direction on the side surface 411s of the main body portion 411. The protruding portion 922 may be, for example, a plate-like portion made of an elastic material and having a hook portion F1 protruding at its tip toward the tubular portion 11. The elastic material may be, for example, a metal material such as iron or stainless steel, or a resin. The multiple elastic portions 92 may be configured as a single member together with the main body portion 411 of the base portion 41, or may be fixed to the main body portion 411 by adhesive bonding, joining, fastening, or fitting.

[0148] 20 to 22 , as an example of one or more convex portions 91, a first convex portion 91a and a second convex portion 91b are depicted, each positioned on the outer circumferential portion 11o of the cylindrical portion 11. As an example of the multiple elastic portions 92, a first elastic portion 92a and a second elastic portion 92b are depicted, each fixed to two different circumferential locations on the side surface 411s of the main body portion 411. The first elastic portion 92a includes a first fixed portion 921a fixed to the main body portion 411 and a first protruding portion 922a protruding from the main body portion 411 along the outer circumferential portion 11o of the cylindrical portion 11. The first protruding portion 922a is a plate-shaped portion made of an elastic material and has a first hook portion F1a protruding from its tip toward the cylindrical portion 11. The second elastic portion 92b includes a second fixed portion 921b fixed to the main body portion 411, and a second protruding portion 922b protruding from the main body portion 411 along the outer periphery 11o of the tubular portion 11. The second protruding portion 922b is a plate-shaped portion made of an elastic material, and has a second hook portion F1b protruding from its tip toward the tubular portion 11.

[0149] 20 , in the state of the lighting device 1, the hook portion F1 of each of the multiple elastic portions 92 is hooked onto one or more convex portions 91, thereby fixing the base portion 41 to the housing 10 in a state where it can be removed to the outside Ex1 of the housing 10. In the example of FIG. 20 , the first hook portion F1a of the first elastic portion 92a is hooked onto the first convex portion 91a, and the second hook portion F1b of the second elastic portion 92b is hooked onto the second convex portion 91b. This fixes the base portion 41 to the housing 10 in a state where it can be removed to the outside Ex1 of the housing 10.

[0150] 21 , in each of the multiple elastic portions 92, the protruding portion 922 can be elastically deformed to release the hook portion F1 from being hooked on the convex portion 91, while moving the first member 40 in a direction away from the first portion 12. The example in FIG. 21 shows a state in which the first elastic portion 92a elastically deforms the first protruding portion 922a to release the first hook portion F1a from being hooked on the first convex portion 91a, and the second elastic portion 92b elastically deforms the second protruding portion 922b to release the second hook portion F1b from being hooked on the second convex portion 91b, while moving the first member 40 in a direction away from the first portion 12. This allows the first member 40 including the base portion 41 to be detached from the housing 10, as shown in FIG. 22 .

[0151] Furthermore, after removing the first member 40 from the housing 10, by realizing the three states illustrated in Figures 20 to 22 in the reverse order, a new first member 40 can be attached and fixed to the housing 10, as illustrated in Figure 20.

[0152] Here, for example, the multiple elastic portions 92 may be located at multiple locations centered on a virtual rotation axis Ax0 corresponding to the second optical axis Ax2 or the virtual rotation axis Ax3. These multiple locations may include, for example, a first location where one elastic portion 92 is located and two or more locations that are sequentially reached by rotation of the first predetermined angle θ0 around the virtual rotation axis Ax0 using the first location as a reference. Furthermore, for example, the multiple convex portions 91 may be located at multiple locations centered on the virtual rotation axis Ax0. These multiple locations may include, for example, a first location where one convex portion 91 is located and two or more locations that are sequentially reached by rotation of the first predetermined angle θ0 around the virtual rotation axis Ax0 using the first location as a reference.

[0153] For example, assume that the first predetermined angle θ0 is 120 degrees. In this case, three elastic portions 92 may be located at three locations centered around the virtual rotation axis Ax0. These three locations include a first location where one elastic portion 92 is located and two locations that are located sequentially by rotating 120 degrees around the virtual rotation axis Ax0 from the first location. Furthermore, for example, three convex portions 91 may be located at three locations centered around the virtual rotation axis Ax0. These three locations include a first location where one convex portion 91 is located and two locations that are located sequentially by rotating 120 degrees around the virtual rotation axis Ax0 from the first location.

[0154] Here, if the virtual rotation axis Ax0 corresponds to the virtual rotation axis Ax3, as in the third embodiment, the base unit 41 can be removably fixed to the housing 10 at two or more rotation angles around the virtual rotation axis Ax0 passing through the second opening 10b. In other words, when the base unit 41 is released from the housing 10, it can be removably fixed to the housing 10 at two or more rotation angles around the virtual rotation axis Ax0 passing through the second opening 10b. More specifically, for example, after the base unit 41 is released from the housing 10, the base unit 41 can be rotated around the virtual rotation axis Ax0 by an angle n times the first predetermined angle θ0 (n is a natural number), and then fixed to the housing 10. This allows the region A0 irradiated with the excitation light L0 in the wavelength conversion unit 422 to be changed. As a result, deterioration of the wavelength conversion unit 422 can be reduced. This allows the life of the lighting device 1 to be extended.

[0155] Here, for example, the housing 10 may have, as one or more first parts of the attachment mechanism 90, multiple elastic parts each having a hook at its tip, and the base 41 may have, as one or more second parts of the attachment mechanism 90, one or more convex parts onto which the hooks are hooked. In this case, the base 41 may have, for example, a corner formed by the side surface 411s and the fifth surface 411u of the main body 411, or a protrusion, depression, or step on the side surface 411s, as one or more convex parts. Each of the multiple elastic parts may include, for example, a fixed part fixed to the outer periphery of the tubular part 11 and a protruding part protruding from the tubular part 11 along the side surface 411s of the main body 411 of the base 41, and a hook may be present at the tip of each protruding part.

[0156] Fig. 23 is a cross-sectional view schematically showing the configuration of another example of the attachment mechanism 90 in a lighting device 1 according to another fourth example. Fig. 24 is a cross-sectional view schematically showing an example of a state in the middle of removing the first member 40 from the housing 10 in a lighting device 1 having the attachment mechanism 90 according to another example. Fig. 25 is a cross-sectional view schematically showing an example of a state after the first member 40 has been removed from the housing 10 in a lighting device 1 having the attachment mechanism 90 according to another example.

[0157] 23 , the housing 10 has, for example, a plurality of ball plunger portions 93 as one or more first portions of the attachment mechanism 90. The base portion 41 has, for example, one or more hook portions 94 as one or more second portions of the attachment mechanism 90. In FIGS. 23 to 25 , two ball plunger portions 93 and two hook portions 94 are schematically depicted as a specific example.

[0158] The plurality of ball plunger portions 93 are located on the outer circumferential portion 11o of the cylindrical portion 11. The ball plunger portion 93 is a positioning mechanism having a shape in which a sphere is pushed by a spring inside a cylindrical case and a part of the sphere protrudes outside the case. The plurality of ball plunger portions 93 are located, for example, at a plurality of different positions in the circumferential direction on the outer circumferential portion 11o of the cylindrical portion 11.

[0159] The one or more hook portions 94 protrude from the outer periphery of the main body portion 411 of the base portion 41 along the outer periphery 11o of the tubular portion 11. The main body portion 411 and the one or more hook portions 94 may be configured as a single member, or may have a configuration in which two or more members are connected by bonding, joining, fastening, or fitting.

[0160] 23 to 25 , as an example of the plurality of ball plunger portions 93, a first ball plunger portion 93a and a second ball plunger portion 93b are depicted, each positioned on the outer circumferential portion 11o of the cylindrical portion 11. As an example of the one or more hook portions 94, a first hook portion 94a and a second hook portion 94b are depicted, each protruding from two different circumferential positions on the outer circumferential portion of the main body portion 411 of the base portion 41.

[0161] 23 , in the state of the lighting device 1, the multiple hook portions 94 are hooked onto the spheres of the multiple ball plunger portions 93, thereby fixing the base portion 41 to the housing 10 in a state where it can be removed to the outside Ex1 of the housing 10. In the example of FIG. 23 , the first hook portion 94a is hooked onto the sphere of the first ball plunger portion 93a, and the second hook portion 94b is hooked onto the sphere of the second ball plunger portion 93b. As a result, the base portion 41 is fixed to the housing 10 in a state where it can be removed to the outside Ex1 of the housing 10.

[0162] 24 , in each of the plurality of ball plunger portions 93, the spring can be compressed to release the hook portion 94 from being caught on the sphere, while moving the first member 40 in a direction away from the first portion 12. The example in FIG. 24 shows a state in which the spring in the first ball plunger portion 93a is compressed to release the first hook portion 94a from being caught on the sphere, and the spring in the second ball plunger portion 93b is compressed to release the second hook portion 94b from being caught on the sphere, while moving the first member 40 in a direction away from the first portion 12. This allows the first member 40 including the base portion 41 to be removed from the housing 10, as shown in FIG. 25 .

[0163] Furthermore, after removing the first member 40 from the housing 10, by realizing the three states illustrated in Figures 23 to 25 in the reverse order, a new first member 40 can be attached and fixed to the housing 10, as illustrated in Figure 23.

[0164] Here, for example, the multiple ball plunger portions 93 may be located at multiple locations centered on a virtual rotation axis Ax0 corresponding to the second optical axis Ax2 or the virtual rotation axis Ax3. The multiple locations may include, for example, a first location where one ball plunger portion 93 is located and two or more locations that are sequentially reached by rotation of the first predetermined angle θ0 around the virtual rotation axis Ax0 using the first location as a reference. Furthermore, for example, the multiple hook portions 94 may be located at multiple locations centered on the virtual rotation axis Ax0. The multiple locations may include, for example, a first location where one hook portion 94 is located and two or more locations that are sequentially reached by rotation of the first predetermined angle θ0 around the virtual rotation axis Ax0 using the first location as a reference.

[0165] For example, assume that the first predetermined angle θ0 is 120 degrees. In this case, three ball plunger portions 93 may be located at three locations centered around the imaginary rotation axis Ax0. These three locations include a first location where one ball plunger portion 93 is located and two locations that are successively located by rotating 120 degrees around the imaginary rotation axis Ax0 from the first location. Furthermore, for example, three hook portions 94 may be located at three locations centered around the imaginary rotation axis Ax0. These three locations include a first location where one hook portion 94 is located and two locations that are successively located by rotating 120 degrees around the imaginary rotation axis Ax0 from the first location.

[0166] Here, if the virtual rotation axis Ax0 corresponds to the virtual rotation axis Ax3, as in the third embodiment, the base unit 41 can be removably fixed to the housing 10 at two or more rotation angles around the virtual rotation axis Ax0 passing through the second opening 10b. In other words, when the base unit 41 is released from the housing 10, it can be removably fixed to the housing 10 at two or more rotation angles around the virtual rotation axis Ax0 passing through the second opening 10b. More specifically, for example, after the base unit 41 is released from the housing 10, the base unit 41 can be rotated around the virtual rotation axis Ax0 by an angle n times the first predetermined angle θ0 (n is a natural number), and then fixed to the housing 10. This allows the region A0 irradiated with the excitation light L0 in the wavelength conversion unit 422 to be changed. As a result, deterioration of the wavelength conversion unit 422 can be reduced. This allows the life of the lighting device 1 to be extended.

[0167] 4. Others In each of the above embodiments, the base unit 41 may be fixed to the housing 10 in a removable manner to the exterior Ex1 of the housing 10 using various members or objects, such as an adhesive. This configuration also allows the first member 40 including the wavelength conversion unit 422 to be removed from the housing 10 and replaced. The adhesive may have low adhesion, for example. A low adhesion adhesive may be made using a curable adhesive resin, such as an epoxy resin or a silicone resin. The adhesive may also contain a thermally conductive filler. An example of an adhesive containing a thermally conductive filler is an adhesive having a matrix made of a curable adhesive resin, such as an epoxy resin or a silicone resin, and a large number of thermally conductive particles dispersed in the matrix. The thermally conductive particles may be, for example, one or more of silver particles, gold particles, aluminum nitride particles, and boron nitride particles.

[0168] In the first and second embodiments, the base portion 41 may be fixed to the housing 10 in a state in which it can be removed to the outside Ex1 of the housing 10 by a configuration (also referred to as the first configuration) in which the male thread portion (also referred to as the first male thread portion) of the base portion 41 is fitted into the female thread portion (also referred to as the first female thread portion) of the housing 10, or a configuration (also referred to as the second configuration) in which the male thread portion (also referred to as the second male thread portion) of the housing 10 is fitted into the female thread portion (also referred to as the second female thread portion) of the base portion 41.

[0169] An example of the first configuration is a configuration in which the second opening 10b has a first female thread portion on its inner periphery, and the base portion 41 has a first male thread portion on its outer periphery. Here, the second opening 10b may have, for example, a portion having a first inner diameter (also referred to as a first small diameter portion) located on the internal space 10is side and a portion having a second inner diameter (also referred to as a first large diameter portion) located on the outside Ex1 side and larger than the first inner diameter, and the first large diameter portion may have a first female thread portion on its inner periphery. Furthermore, the convex portion 412 may have, for example, a portion having a first outer diameter (also referred to as a second small diameter portion) located on the wavelength converting portion 422 side and a portion having a second outer diameter (also referred to as a second large diameter portion) located on the main body portion 411 side and larger than the first outer diameter, and the second large diameter portion may have a first male thread portion on its outer periphery. As another example of the first configuration, a configuration may be adopted in which the housing 10 has, at the second end E2, a circular groove portion with a first female thread portion located on the inner circumference and centered on the second opening 10b that is recessed in a direction away from the main body portion 411, and the base portion 41 has, on the housing 10 side, a first male thread portion located on the outer circumference and a cylindrical portion protruding from the main body portion 411 toward the housing 10.

[0170] One example of the second configuration is a configuration in which the housing 10 has a second male thread portion on the outer periphery (also referred to as a first outer periphery) on the second end E2 side, and the base portion 41 has a second female thread portion located on its inner periphery (also referred to as a first inner periphery) and a cylindrical portion protruding from the main body portion 411 along the first outer periphery of the housing 10. Another example of the second configuration is a configuration in which the housing 10 has, at the second end E2, a second male thread portion located on its outer periphery and an annular groove portion centered on the second opening 10b that is recessed in a direction away from the main body portion 411, and the base portion 41 has, on the housing 10 side, a second female thread portion located on its inner periphery and a cylindrical portion protruding from the main body portion 411 toward the housing 10.

[0171] In each of the above embodiments, for example, one or more lenses 321 in the lens optical system 32 may include a first lens 321a and a second lens 321b but not a third lens 321c, or may include a first lens 321a but not a second lens 321b or a third lens 321c.

[0172] In each of the above embodiments, for example, any of a concave lens, a meniscus lens, and a convex lens may be appropriately applied to each of the one or more lenses 321. Furthermore, each of the one or more lenses 321 may be any of a spherical lens and an aspherical lens.

[0173] In each of the above embodiments, for example, the inner wall of the housing 10 may have a protrusion or recess for fixing one or more lenses 321. In this case, for example, the number of holding members 61 in the holding mechanism 60 may be appropriately reduced.

[0174] In each of the above embodiments, for example, one or more of the holding members 61 may have a function for reducing stray light.

[0175] In each of the above embodiments, for example, the wavelength separation filter 31 is not limited to a dichroic mirror, and may be realized using other configurations such as a dichroic prism.

[0176] In each of the above-described embodiments, for example, the wavelength conversion portion 422 may be fixed directly to the base portion 41 without using the second holding portion 421 .

[0177] In each of the above embodiments, for example, the light source 20 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 a cladding. The cladding has a lower refractive index than the core and covers the core. The excitation light L0 can transmit 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 transmit through the rod lens while being totally reflected at the side of the rod lens. The incident ends of these light-guiding members correspond to a first end face located at the longitudinal end of the fiber or a first end face located at the end of the rod lens, and the exit ends of the light-guiding members correspond to a second end face opposite the first end face of the fiber or a 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 exits from the exit end of the light-guiding member. In this case, the exit section 20e of the light source 20 corresponds to the exit end of the light-guiding member.

[0178] In each of the above embodiments, for example, the light source 20 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 31. Furthermore, various lenses may be positioned between the light source 20 and the wavelength separation filter 31.

[0179] In each of the above embodiments, the first portion 12 may be light-absorbing. Light-absorbing refers to a material having a light absorption rate of 60% or more in the visible light range. Furthermore, the inner circumferential surface of the first portion 12 that forms the second opening 10b may be light-absorbing. The inner circumferential surface of the first portion 12 may have a high absorption rate for the fluorescence L1. The absorption rate for the fluorescence L1 at the inner circumferential surface of the first portion 12 may be, for example, 60% or more, 80% or more, or 90% or more. The inner circumferential surface of the first portion 12 may have a high absorption rate for the entire wavelength range of the fluorescence L1, or may have a high absorption rate for the peak wavelength of the fluorescence L1. For example, the absorption rate for the fluorescence L1 at the inner circumferential surface of the first portion 12 may be increased by blackening treatment. Examples of blackening treatments that can be used include chemical conversion coating, plating, and painting. Either a matte or glossy blackening treatment may be used. The inner circumferential surface of the first portion 12 may be made of a black material to increase the absorption rate of the fluorescence L1 at the inner circumferential surface of the first portion 12. The black material may be, for example, one or more of black metal, black metal oxide film, and black resin. The inner circumferential surface of the first portion 12 may be made of a dielectric multilayer film to increase the absorption rate of the fluorescence L1 at the inner circumferential surface of the first portion 12. The dielectric multilayer film has, for example, a structure in which multiple dielectric thin films are stacked. The dielectric may be, for example, SiO ２ , TiO ２ , niobium pentoxide (Nb ２ O ５ ), tantalum pentoxide (Ta ２ O ５ ) and magnesium fluoride (MgF ２ ) is used. This dielectric multilayer film may also be called a low-reflection film or an anti-reflection film.

[0180] Although the lighting device 1 has been described in detail above, the above description is merely an example in all respects, and the lighting device 1 is not limited thereto. Countless examples not illustrated can be envisioned without departing from the scope of this disclosure. The configurations described in the above-described embodiments and various examples can be combined or omitted as appropriate, as long as they are not mutually inconsistent.

[0181] This disclosure includes the following:

[0182] and a lens optical system including one or more lenses positioned on an optical path of the fluorescence from the wavelength conversion unit to the first opening. The lens optical system includes: a wavelength separation filter that guides the excitation light from the light source to the wavelength conversion unit and guides the fluorescence from the wavelength conversion unit to the first opening; and a lens optical system including one or more lenses positioned on an optical path of the fluorescence from the wavelength conversion unit to the first opening. The lens optical system includes: a first member having a wavelength separation filter that guides the excitation light from the light source to the wavelength conversion unit and guides the fluorescence from the wavelength conversion unit to the first opening; a first member having a wavelength separation filter that guides the excitation light from the light source to the wavelength conversion unit and guides the fluorescence from the wavelength conversion unit to the first opening;

[0183] (2) In the illumination device of (1) above, the fluorescence may pass through the first opening and then the third opening, or may pass through the third opening and then the first opening, or may pass through the first opening and then the third opening.

[0184] (3) The lighting device of (1) or (2) above may further include a heat dissipation member that is fixed to the base portion in a state that allows it to be removed from the base portion and that has a plurality of protrusions.

[0185] (4) In the lighting device of (1) or (2) above, the base portion may include a plurality of protrusions.

[0186] (5) In any one of the lighting devices (1) to (4) above, the housing and the base portion may include an attachment mechanism that fixes the base portion to the housing in a state that allows it to be removed to the outside.

[0187] (6) In any one of the lighting devices (1) to (5) above, the base portion may include a convex portion that fits into the second opening from the external side, and the wavelength conversion portion may be fixed on the convex portion.

[0188] (7) In any one of the lighting devices (1) to (6) above, the base portion has a structure that allows it to be fixed to the housing in a state that allows it to be removed from the housing at two or more angles rotated relative to the housing around a virtual rotation axis that passes through the second opening, and the center of the area of ​​the wavelength conversion portion that is irradiated with the excitation light may be located at a position offset from the virtual rotation axis.

[0189] (8) In any one of the lighting devices (1) to (7) above, the housing may include a cylindrical body, the second opening may be located on the opposite side of the internal space from the first opening, and the optical system may be sandwiched between the first part of the housing and the second member.

[0190] (9) In the lighting device of (8) above, the wavelength conversion unit, the wavelength separation filter, and the first opening may be aligned in a first direction, the light source and the wavelength separation filter may be aligned in a second direction intersecting the first direction, and the wavelength separation filter may reflect the excitation light from the light source toward the wavelength conversion unit and transmit the fluorescence from the wavelength conversion unit toward the first opening.

[0191] (10) In any one of the illumination devices (1) to (7) above, the wavelength separation filter and the first opening may be aligned in a first direction, the light source, the wavelength separation filter, and the wavelength conversion unit may be aligned in a second direction intersecting the first direction, and the wavelength separation filter may transmit the excitation light from the light source toward the wavelength conversion unit and reflect the fluorescence from the wavelength conversion unit toward the first opening.

[0192] (11) In any one of the illumination devices (1) to (10) above, the lens optical system may include a first lens and a second lens, and may further include a spacer sandwiched between the first lens and the second lens.

[0193] (12) Any one of the lighting devices (1) to (11) above may further include an annular spacer located between the outer surface of the first portion and the base portion.

[0194] REFERENCE SIGNS LIST 1 Illumination device 10 Housing 10a First opening 10b Second opening 10if Inner surface 10is Internal space 12 First portion 20 Light source 30 Optical system 31 Wavelength separation filter 32 Lens optical system 321 Lens 321a First lens 321b Second lens 321c Third lens 40 First member 41 Base portion 412 Convex portion 422 Wavelength conversion portion 50 Second member 50a Third opening 61 Holding member 61a First holding member 70 Heat dissipation member 70a First heat dissipation member 72 Protrusion 72a First protrusion 73a Third protrusion 80 Annular spacer 90 Mounting mechanism A0 Area Ax0, Ax3 Virtual rotation axis Ex1 Outside L0 Excitation light L1 Fluorescence P0 Center

Claims

1. a housing having a first portion including a first opening that is open to the outside and a second opening that is open to the outside; A light source that emits excitation light; an optical system located in an internal space of the housing; a wavelength converting unit that emits fluorescence having a wavelength spectrum different from that of the excitation light in response to irradiation of the excitation light from the light source, and a first member having a base unit to which the wavelength converting unit is fixed; a second member fixed to the housing from the first opening side and having a third opening through which the fluorescent light passes, the optical system includes a wavelength separation filter that guides the excitation light from the light source to the wavelength conversion unit and guides the fluorescence from the wavelength conversion unit to the first opening, and a lens optical system including one or more lenses located on an optical path of the fluorescence from the wavelength conversion unit to the first opening, the base portion covers the second opening from the exterior side and is fixed to the housing in a state in which it can be removed to the exterior side; The wavelength converting portion is positioned in a state where it is exposed to the internal space, The optical system is sandwiched between the second member and an inner surface of the housing.

2. 2. The lighting device according to claim 1, the fluorescence passes through the first opening and then the third opening, or passes through the third opening and then the first opening, or passes through the first opening and then the third opening.

3. 3. The lighting device according to claim 1, The lighting device further comprises a heat dissipation member fixed to the base portion in a state capable of being detached from the base portion, the heat dissipation member having a plurality of protrusions.

4. 3. The lighting device according to claim 1, The base portion includes a plurality of protrusions.

5. 3. The lighting device according to claim 1, The lighting device, wherein the housing and the base portion include an attachment mechanism that fixes the base portion to the housing in a state that allows the base portion to be removed to the outside.

6. 3. The lighting device according to claim 1, the base portion includes a protrusion that is fitted into the second opening from the outside side, The illumination device, wherein the wavelength converting portion is fixed on the convex portion.

7. 3. The lighting device according to claim 1, the base portion has a structure that allows it to be fixed to the housing in a state that allows it to be detached to the outside at two or more angles rotated relative to the housing around a virtual rotation axis that passes through the second opening; a center of a region of the wavelength converting unit that is irradiated with the excitation light is positioned at a position shifted from the virtual axis of rotation.

8. 3. The lighting device according to claim 1, The housing includes a cylindrical body, The second opening is located on an opposite side of the internal space from the first opening, The optical system is sandwiched between the first portion of the housing and the second member.

9. 9. The lighting device according to claim 8, the wavelength converting portion, the wavelength separation filter, and the first opening are aligned in a first direction, the light source and the wavelength separation filter are arranged in a second direction intersecting the first direction, The wavelength separation filter reflects the excitation light from the light source toward the wavelength conversion unit, and transmits the fluorescence from the wavelength conversion unit toward the first opening.

10. 3. The lighting device according to claim 1, the wavelength separation filter and the first opening are aligned in a first direction, the light source, the wavelength separation filter, and the wavelength conversion unit are arranged in a second direction intersecting the first direction, The wavelength separation filter transmits the excitation light from the light source toward the wavelength conversion unit and reflects the fluorescence from the wavelength conversion unit toward the first opening.

11. 3. The lighting device according to claim 1, the lens optical system includes a first lens and a second lens, The lighting device further comprises a spacer sandwiched between the first lens and the second lens.

12. 3. The lighting device according to claim 1, The lighting device further comprising an annular spacer located between the exterior surface of the first portion and the base.