Lighting device

Abstract

A lighting device comprising a housing, a first light source, and first lens optics. The housing has an opening. The first light source includes a first exit unit for causing first light to exit into the internal space of the housing. The first lens optics include, on a first light path, at least one first lens positioned between the first exit unit and the opening of the housing. The first lens optics cause the first light from the first exit unit to be imaged onto a virtual image plane on the opening side, and cause the first light to exit via the opening. The numerical aperture of the first lens optics is defined by an angle greater than or equal to the spread angle of the first light from the first exit unit.

Description

Cross - reference to related applications

[0001] This application claims the priority of Japanese Application No. 2021 - 108718 (filed on June 30, 2021) and International Application No. PCT / JP2022 / 006911 (filed on February 21, 2022), and the entire disclosure of these applications is incorporated herein by reference for that purpose.

Technical Field

[0002] This disclosure relates to a lighting device.

Background Art

[0003] There is known a lighting device that reflects light from a light source with an elliptical mirror and irradiates an illumination space (for example, Patent Documents 1 and 2).

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

[0005] A lighting device is disclosed.

[0006] The lighting device includes a housing, a first light source, and a first lens optical system. The housing has an opening. The first light source has a first emission part that emits first light into the internal space of the housing. The first lens optical system includes at least one first lens located between the first emission part and the opening in the path of the first light, and forms an image of the first light from the first emission part on a virtual image plane on the opening side, and emits the first light from the opening. The housing includes an opening member having a second opening where the first lens is located, and an attachment member attached in a state of closing the second opening with respect to the surface of the opening member on the side opposite to the opening. The first emission portion is located in a region of the attachment member facing the second opening.

Brief Description of the Drawings

[0007]

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Mode for Carrying Out the Invention

[0008] <First Embodiment> FIG. 1 is a cross-sectional view schematically showing an example of the configuration of a lighting device 1 according to the first embodiment. The lighting device 1 is a device that emits a first light L1 into an illumination space S1. The lighting device 1 is disposed, for example, on the ceiling of the illumination space S1.

[0009] As illustrated in FIG. 1, the lighting device 1 includes a first light source 2, a first lens optical system 3, and a housing 4.

[0010] The first light source 2 has a first emission portion (for example, an emission surface) 21 that emits the first light L1 into the internal space of the housing 4. The first light L1 is, for example, visible light. The first light source 2 may include, for example, a semiconductor laser element such as a laser diode (LD), a light emitting element such as a VCSEL (Vertical Cavity Surface Emitting LASER) or an SLD (super luminescent diode). The first emission portion 21 of the first light source 2 may be the emission end of the light emitting element.

[0011] Alternatively, in addition to the light emitting element, the first light source 2 may further include a light guiding member such as a fiber and a rod lens. The fiber includes a linear core and a cladding. The cladding has a lower refractive index than the core and covers the core. The first light L1 can transmit through the core while totally reflecting at the interface between the core and the cladding. The rod lens has, for example, a columnar shape. The first light L1 can transmit through the inside of the rod lens while totally reflecting at the side surface of the rod lens.

[0012] The incident end of such a light guide member corresponds to the first end face located at the longitudinal end of the fiber or the first end face located at the longitudinal end of the rod lens, and the exit end of the light guide member corresponds to the second end face on the side opposite to the first end face of the fiber or the second end face on the side opposite to the first end face of the rod lens.

[0013] The first light L1 from the light emitting element is incident on the incident end of the light guide member, travels through the light guide member, and is emitted from the exit end of the light guide member into the internal space of the housing 4. In this case, the first emission portion 21 of the first light source 2 corresponds to the exit end of the light guide member.

[0014] The first emission portion 21 may include a wavelength conversion member 23, and the first light L1 may be fluorescence emitted from the wavelength conversion member 23. The wavelength conversion member 23 is, for example, BaMgAl 10 O 17 :Eu, or (Sr,Ca,Ba) 10 (PO4)6Cl2:Eu,(Sr,Ba) 10 (PO4)6Cl2:Eu or the like. The wavelength conversion member 23 is, for example, (Sr,Ba,Ca)5(PO4)3Cl:Eu,Sr4Al 14 O 25 :Eu or the like as a wavelength conversion material that converts excitation light into blue-green light. The wavelength conversion member 23 is, for example, SrSi2(O,Cl)2N2:Eu, (Sr,Ba,Mg)2SiO4:Eu 2+ , or ZnS:Cu,Al, Zn2SiO4:Mn or the like as a wavelength conversion material that converts excitation light into green light. The wavelength conversion member 23 is, for example, Y2O2S:Eu, Y2O3:Eu, SrCaClAlSiN3:Eu 2+ , CaAlSiN3:Eu, or CaAlSi(ON)3:Eu or the like as a wavelength conversion material that converts excitation light into red light. The wavelength conversion member 23 is, for example, 3Ga5O 12 :Cr or the like as a wavelength conversion material that converts excitation light into light having a wavelength in the near-infrared region.

[0015] In this case, the first light source 2 is excitation light. The excitation light may be, for example, purple light having a peak near 405 nm or blue light having a peak near 450 nm. When the excitation light has a peak in the range from 380 nm to 415 nm and the wavelength conversion member 23 has RGB phosphors, the color rendering property of the lighting device 1 can be enhanced.

[0016] As illustrated in FIG. 1, the first light L1 from the first emission portion 21 of the first light source 2 travels while spreading. In other words, the size of the first light L1 in a cross section perpendicular to the optical axis AX1 of the first light source 2 increases as the distance from the first light source 2 increases. In the example of FIG. 1, the light rays of the first light L1 emitted from each point of the first emission portion 21 are schematically shown by broken lines. The size of the first light L1 may be defined by a contour having 1 / e of the peak value in the light quantity distribution of the first light L1 in a cross section perpendicular to the optical axis AX1. Here, "e" is called the Napier's constant. In other words, the light rays on both outer sides of the first light L1 in FIG. 1 are light rays having 1 / e of the peak value in the light quantity distribution in a cross section perpendicular to the optical axis AX1. 2 The light in the region outside the region surrounded by the above-described contour (i.e., the light rays on both outer sides) may be regarded as noise light. 2 The first lens optical system 3 is located on the path of the first light L1 from the first light source 2 in the internal space of the housing 4. The first lens optical system 3 includes a first lens 31, and condenses the first light L1 from the first light source 2 on a virtual image plane IS1 on the side opposite to the first emission portion 21, that is, on the aperture 4a side. In other words, the first lens optical system 3 is an imaging optical system that forms a real image of the light source image of the first light source 2 on the image plane IS1. The first emission portion 21 has a conjugate relationship with the image plane IS1. Here, the conjugate relationship does not have a strict meaning, and in the region on the aperture 4a side of the first emission portion 21, the portion where the first light L1 is most condensed (the portion where the size of the first light L1 in a cross section perpendicular to the optical axis AX1 of the first light source 2 is the smallest) can be regarded as the image plane IS1.

[0017]

[0018] ​As illustrated in FIG. 1, the first lens optical system 3 may be constituted by a single first lens 31. The first lens 31 may be a spherical biconvex lens. The first lens 31 is formed of a material containing at least one of glass such as optical glass and resin such as acrylic resin, for example.

[0019] In the example of FIG. 1, the first emission part 21 of the first light source 2 is attached to the housing 4, and emits the first light L1 toward the first lens optical system 3. After passing through the first lens optical system 3, the first light L1 passes through the irradiation opening 4a formed in the housing 4 and is emitted to the illumination space S1 outside the housing 4. The irradiation opening 4a is an opening connecting the internal space of the housing 4 and the external illumination space S1.

[0020] In the example of FIG. 1, the housing 4 has a side wall 41, a first member 42, and a second member 43. The side wall 41 has a cylindrical shape (for example, a circular cylindrical shape). In the example of FIG. 1, the central axis of the cylindrical side wall 41 and the optical axis AX1 of the first light source 2 substantially coincide. The first member 42 is located at the first peripheral edge of the side wall 41. The first member 42 has, for example, a plate shape, and the periphery of the first member 42 is connected to the first peripheral edge of the side wall 41. The second member 43 is located at the second peripheral edge opposite to the first peripheral edge of the side wall 41. The second member 43 has, for example, a plate shape, and the periphery of the second member 43 is connected to the second peripheral edge of the side wall 41. The internal space of the housing 4 is formed by the side wall 41, the first member 42, and the second member 43.

[0021] In the example of FIG. 1, a through hole penetrating the first member 42 in the central axis direction is formed in the central portion of the first member 42, and the first light source 2 is located in the through hole. In the example of FIG. 1, an irradiation opening 4a penetrating the second member 43 in the central axis direction is formed in the central portion of the second member 43. In the example of FIG. 1, the second member 43 extends from the lower end of the side wall 41 toward the optical axis AX1 and reaches the periphery of the irradiation opening 4a. That is, the diameter of the irradiation opening 4a is smaller than the inner diameter of the side wall 41. By having such a second member 43 in the housing 4, the irradiation opening 4a can be formed small, and the first lens optical system 3 can be made less visible from the outside of the housing 4, so that a comfortable illumination space with less glare can be realized.

[0022] The first lens optical system 3 is positioned inside the housing 4 between the first light emitting portion 21 of the first light source 2 and the irradiation opening 4a of the housing 4. The first lens optical system 3 condenses the first light L1 from the first light source 2 onto the image plane IS1. In the example of FIG. 1, the image plane IS1 is positioned within the irradiation opening 4a. That is, the position of the first light source 2, the position of the first lens optical system 3, and the optical conditions of the first lens optical system 3 are designed such that the image plane IS1 is positioned within the irradiation opening 4a. Thereby, since the portion where the first light L1 is most condensed is positioned at the opening 4a, when the housing 4 has the second member 43, the opening 4a can be designed to be small. Thereby, it is possible to make it difficult to see the first lens optical system 3 from the outside of the housing 4. As a result, a comfortable illumination space with less glare can be realized.

[0023] Note that the image plane IS1 does not necessarily have to be positioned inside the irradiation opening 4a. The image plane IS1 may be positioned slightly deviated from the irradiation opening 4a in the traveling direction of the first light L1 passing through the irradiation opening 4a. That is, the image plane IS1 may be positioned slightly on the inner side of the housing 4 rather than the irradiation opening 4a, or may be positioned slightly on the illumination space S1 side.

[0024] In this illumination device 1, the imaging magnification of the first lens optical system 3 is equal to or less than the ratio (= M3 / M1) of the size M3 of the irradiation opening 4a to the size M1 of the first light L1 at the first light emitting portion 21 of the first light source 2. The size M1 of the first light L1 at the first light emitting portion 21 can also be said to be the light emitting diameter of the first light emitting portion 21 which is the size of the first light emitting portion 21 itself. For example, it corresponds to the area of the end face of the core of the fiber or the area of the end face of the rod lens. Alternatively, when the first light emitting portion 21 is the end face of the light emitting element, the size of the end face of the light emitting element itself corresponds to the size M1 of the first light L1 at the first light emitting portion 21. Alternatively, when the first light emitting portion 21 is the surface of the wavelength conversion member 23, the size of the surface of the wavelength conversion member 23 corresponds to the size M1 of the first light L1 at the first light emitting portion 21.

[0025] Since the first light source 2 is, for example, an LD, the light emitting diameter can be made smaller compared to an LED or a VCSEL, and the size M2 of the first light L1 on the image plane IS1 can be made relatively smaller. As a result, a comfortable illumination space with less glare can be realized.

[0026] When the cross-sectional shape of the first light L1 is circular, the size M1 may be regarded as the diameter of the first light L1. When the cross-sectional shape of the first light L1 is rectangular, the size M1 may be regarded as the diagonal length of the first light L1. The size M1 of the first light L1 at the first light emitting portion 21 is, for example, about 2 mm to 3 mm.

[0027] The size M3 of the irradiation aperture 4a refers to the area of the irradiation aperture 4a in a cross-section perpendicular to the optical axis AX1 at the irradiation aperture 4a. When the shape of the irradiation aperture 4a as viewed along the optical axis AX1 is circular or rectangular, the diameter or diagonal length of the irradiation aperture 4a is, for example, about several millimeters to several tens of millimeters. The diameter of the irradiation aperture 4a may be, for example, about 5 mm to 15 mm. When the surface forming the irradiation aperture 4a is inclined, the size M3 of the irradiation aperture 4a differs at each position of the optical axis AX1. In this case, as the size M3 of the irradiation aperture 4a, for example, its minimum value can be adopted.

[0028] The imaging magnification is the ratio of the size M2 of the first light L1 on the image plane IS1 to the size M1 of the first light L1 at the first light emitting portion 21 of the first light source 2.

[0029] Since the imaging magnification is equal to or less than the above ratio, the size M2 of the first light L1 on the image plane IS1 can be made equal to or less than the size M3 of the irradiation aperture 4a. Therefore, the possibility of the first light L1 entering the second member 43 can be reduced, and consequently, the possibility of the first light L1 being reflected or scattered by the inner surface of the cylindrical side wall 41 or the second member 43 can be reduced. Thereby, unnecessary reflected and scattered light leaking from the irradiation aperture 4a can be reduced.

[0030] The imaging magnification of the first lens optical system 3 may be set such that the size of the first light L1 passing through the irradiation aperture 4a is smaller than the irradiation aperture 4a. According to this, the reflected scattered light can be further reduced.

[0031] Next, the illumination device 1 will be further described by introducing the divergence angle θ1 of the first light L1 at the first emission part 21 of the first light source 2. The divergence angle θ1 is, for example, the angle formed by the outermost light rays of the first light L1 at the first emission part 21 in a cross section including the optical axis AX1 (for example, the plane of FIG. 1). Since it is considered that the divergence angles of the first light L1 emitted from each point of the first emission part 21 are the same as each other, the divergence angle θ1 is also the angle formed by the outermost light rays of the first light L1 emitted from each point of the first emission part 21 of the first light source 2. Here, the outermost light rays of the first light L1 may be, for example, the light rays defining the emission diameter of the first light L1. Also, the outermost light rays of the first light L1 may be the light rays defining the size of the first light L1 in a cross section perpendicular to the optical axis AX1 of the first light source 2.

[0032] In the illumination device 1, the divergence angle θ1 of the first light source 2 is equal to or less than the angle θ2 defining the numerical aperture of the first lens optical system 3. The numerical aperture is the product of the sine of half of the angle θ2 and the refractive index. FIG. 2 is a diagram for explaining the angle θ2 defining the numerical aperture of the first lens optical system 3. The angle θ2 referred to here is, for example, the angle formed by the outermost light rays of the virtual light passing through the effective region of the first lens optical system 3 from the first emission part 21. The effective region referred to here corresponds to the light passing region where the optical performance of the first lens optical system 3 can be exerted. For example, the effective region of the first lens 31 is the region excluding a predetermined peripheral width from the main surface of the first lens 31. As a more specific example, the effective region of the first lens 31 may be the region surrounded by the inner peripheral edge of the portion of the housing 4 (that is, the lens holder) holding the periphery of the first lens 31.

[0033] Since the divergence angle θ1 is less than or equal to the angle θ2, the first light L1 can pass through the effective region of the first lens optical system 3. Therefore, the first light L1 hardly enters the edge of the first lens 31, and unnecessary reflection and scattering of the first light L1 generated at the edge can be suppressed or avoided.

[0034] As described above, in the lighting device 1, the imaging magnification of the first lens optical system 3 is less than or equal to the above ratio, and the divergence angle θ1 is less than or equal to the angle θ2. Therefore, unnecessary reflection and scattering of the first light L1 at the first lens optical system 3 and the periphery of the irradiation aperture 4a can be suppressed or avoided. Thus, the lighting device 1 can emit most of the first light L1 from the first light source 2 to the lighting space S1 through the irradiation aperture 4a. In other words, the light amount of the first light L1 emitted to the lighting space S1 can be improved. Further, since the reflected and scattered light leaking into the lighting space S1 can be reduced, unevenness such as glare of the first light L1 emitted to the lighting space S1 can also be suppressed. For this reason, the lighting device 1 can irradiate the lighting space S1 with the first light L1 of high efficiency and high quality.

[0035] Further, the first light L1 may be emitted from the irradiation aperture 4a so as not to contact the housing 4. Here, "not to contact" does not mean in a strict sense. As long as the light rays on both outer sides of the first light L1 in the space from the first emission part 21 to the irradiation aperture 4a do not contact the housing 4, for example, noise light such as scattered light may contact the housing 4.

[0036] FIG. 3 is a cross-sectional view schematically showing a first aspect of the configuration of the lighting device 1. In the example of FIG. 3, the image plane IS1 is curved. As a specific example, the image plane IS1 is curved so as to be convex toward the illumination space S1. Such a first lens optical system 3 can be configured by an inexpensive first lens 31. Therefore, the manufacturing cost of the lighting device 1 can be reduced. The first lens 31 may have a continuous curved surface. For example, the main surface of the first lens 31 through which the first light L1 passes may be composed only of a curved surface having no step. In other words, the first lens 31 may not be a Fresnel lens. Thereby, scattering or reflection in the first lens 31 can be reduced. As a result, a comfortable illumination space with less glare can be realized.

[0037] FIG. 4 is a cross-sectional view schematically showing a second aspect of the configuration of the lighting device 1. In the example of FIG. 4, the first lens optical system 3 includes a plurality of first lenses 31. The plurality of first lenses 31 are arranged side by side in the path of the first light L1. The plurality of first lenses 31 may be arranged side by side in the optical axis direction of the first light L1. Such a plurality of first lenses 31 may also be called a compound lens. By combining such a plurality of first lenses 31, it is possible to easily obtain the optical characteristics required for the first lens optical system 3 even when a special optical element such as a Fresnel lens is not used. FIG. 5 is a cross-sectional view schematically showing a third aspect of the configuration of the lighting device 1. The configuration of the third aspect is the same as that of the second aspect. As shown in the third aspect, between the plurality of first lenses 31, there may be a portion (waist portion LW1) where the light diameter of the first light L1 is smaller than the light diameter passing through each of the plurality of first lenses 31. Specifically, the minimum value of the light diameter between two adjacent first lenses 31 (that is, the diameter of the waist portion LW1) may be smaller than the minimum value of the light diameter of the first light L1 in each of the two first lenses 31. According to the second and third aspects, for example, a first lens optical system 3 with a high imaging magnification can be easily obtained. Further, the first lens optical system 3 may have, for example, three or more lenses arranged side by side in the optical axis direction of the first light L1. Thereby, the optical characteristics required for the first lens optical system 3 can be obtained more easily.

[0038] In the examples of FIGS. 1 to 5, although each first lens 31 is a spherical lens, each first lens 31 may be an aspherical lens or a free-form surface lens.

[0039] Also, referring to FIG. 1, the divergence angle θ3 of the first light L1 in the illumination space S1 is smaller than the divergence angle θ1 of the first light L1 incident on the first lens optical system 3. In other words, the first lens optical system 3 is designed such that the divergence angle θ3 is smaller than the divergence angle θ1. It can be said that the divergence angle θ1 is the divergence angle of the first light L1 immediately before the first lens optical system 3, and it can also be said that the divergence angle θ3 is the divergence angle of the first light L1 immediately after the image plane IS1. As a specific example regarding the divergence angle θ3, in the illumination device 1, the orientation angle (for example, half-value angle) of the first light L1 emitted from the irradiation aperture 4a may be less than 60 degrees. Thereby, for example, in the illumination space S1 where a plurality of illumination devices 1 are installed at regular intervals, the glare of the illumination devices 1 entering the field of view can be reduced. As a result, the comfort of the illumination space S1 can be enhanced. 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.

[0040] Also, in the examples of FIGS. 1, 3 to 5, the distance between the first emission part 21 and the irradiation aperture 4a is larger than the inner diameter of the housing 4. The distance between the first emission part 21 and the irradiation aperture 4a here is, for example, the distance in the path along the optical axis AX1. When this distance is large, the interval between the first lens optical system 3 and the irradiation aperture 4a can be increased. When the first lens optical system 3 includes a plurality of first lenses 31, the interval between the first lens 31 closest to the irradiation aperture 4a and the irradiation aperture 4a can be increased. For this reason, it is possible to make the first lens optical system 3 less visible from the outside of the housing 4, and a more comfortable illumination space S1 with less glare can be realized. Note that the distance between the first lens optical system 3 and the irradiation aperture 4a may be made larger than the inner diameter of the housing 4.

[0041] <Second Embodiment> In the present embodiment, since the angle θ2 defining the numerical aperture of the first lens optical system 3 is equal to or greater than the divergence angle θ1 of the first light L1 in the first light emitting portion 21, unnecessary reflection and scattering of the first light L1 inside the housing 4 can be suppressed. of , a slight part of the first light L1 may be reflected or scattered on the surface of each first lens 31. When such unnecessary reflected and scattered light is irradiated onto the illumination space S1 through the irradiation aperture 4a, slight unevenness may occur.

[0042] Therefore, in the second embodiment, it is intended to further suppress the unevenness of the first light L1 irradiated onto the illumination space S1. Hereinafter, the reflected and scattered light of the first light L1 reflected and scattered inside the housing 4 is also referred to as reflected and scattered light L11. The reflected and scattered light L11 is a part of the first light L1 that deviates from the path of the first light L1 that forms an image on the image plane IS1, and may be either reflected light or scattered light.

[0043] FIG. 6 is a cross-sectional view schematically showing an example of the configuration of the illumination device 1A according to the second embodiment. The illumination device 1A is different from the illumination device 1 in terms of the presence or absence of the light reduction structure 5. The light reduction structure 5 is located inside the housing 4. The light reduction structure 5 is arranged to suppress the reflected and scattered light L11 emitted from the irradiation aperture 4a.

[0044] The first lens optical system 3 of the illumination device 1A includes a plurality of first lenses 31 and one or more spacers 32. In the example of FIG. 6, the first lens optical system 3 includes two first lenses 31 and one spacer 32. The spacer 32 is a member that defines the interval between the two first lenses 31. The spacer 32 is located between two adjacent first lenses 31 and is in contact with both first lenses 31. Thereby, the interval between the two first lenses 31 can be made to coincide with the thickness of the spacer 32 (the thickness along the optical axis AX1). The spacer 32 has, for example, a ring shape surrounding the optical axis AX1.

[0045] In the example of FIG. 6, the light reduction structure 5 is located on the inner wall of the spacer 32 and is exposed to the internal space of the housing 4. The light reduction structure 5 includes, for example, a reflection reduction portion 51. The reflection reduction portion 51 may include an absorption film having a high absorption rate for the first light L1. The absorption rate may be, for example, 60% or more, 80% or more, or 90% or more. The reflection reduction portion 51 may have a high absorption rate for the entire wavelength range of the first light L1, or may have a high absorption rate for the peak wavelength. The absorption rate of the reflection reduction portion 51 with respect to the first light L1 is higher than the absorption rate of the spacer 32 with respect to the first light L1.

[0046] Such a reflection reduction portion 51 is formed, for example, by performing a blackening treatment on the inner wall of the spacer 32. As a specific example, the reflection reduction portion 51 is formed on the inner wall of the spacer 32 by a blackening treatment such as a chemical conversion treatment, plating, and painting. As the blackening treatment, a non-glossy blackening treatment may be employed, or a glossy blackening treatment may be employed. Such a reflection reduction portion 51 is composed of a black material. The material includes, for example, at least one of a black metal, a black metal oxide film, and a black resin.

[0047] Alternatively, the reflection reduction portion 51 may include a dielectric multilayer film. The dielectric multilayer film has a structure in which, for example, a plurality of dielectric thin films are laminated. As the dielectric, for example, one or more materials among titanium oxide (TiO2), SiO2, niobium pentoxide (Nb2O5), tantalum pentoxide (Ta2O5), and magnesium fluoride (MgF2) are employed. Such a dielectric multilayer film may also be called an antireflection film or an antireflection coating.

[0048] The reflection reduction portion 51 may be directly formed on the inner wall of the spacer 32, or may be formed on a predetermined film-like substrate, and the substrate may be attached to the inner wall of the spacer 32. For example, the substrate may be attached to the inner wall of the spacer 32 by an adhesive.

[0049] Alternatively, the reflection reduction part 51 may include flocked paper. For example, the flocked paper can be composed of a base material such as paper and cloth, and chemical fibers adhered to the base material in an upright state. If black flocked paper is adopted, the reflection of the reflected scattered light L11 can be further suppressed compared to other colored flocked papers.

[0050] In such a lighting device 1A, for example, when the reflected scattered light L11 reflected and scattered by the first lens optical system 3 travels toward the inner wall of the spacer 32, it enters the reflection reduction part 51. Since the reflection reduction part 51 suppresses the reflection of the reflected scattered light L11, the reflected scattered light L11 emitted from the irradiation aperture 4a can be further reduced. Therefore, the lighting device 1A can further emit a higher-quality first light L1 into the illumination space S1.

[0051] FIG. 7 is an enlarged view schematically showing a part of another example of the light reduction structure 5. The light reduction structure 5 includes a concavo-convex shape 52. The concavo-convex shape 52 is, for example, the shape of the inner wall surface of the spacer 32, and in FIG. 7, a part of it is schematically shown. The concavo-convex shape 52 has concavities and convexities in the optical axis direction parallel to the optical axis AX1. That is, the concavo-convex shape 52 has a shape in which concave portions and convex portions are arranged alternately in a cross section including the optical axis AX1.

[0052] In the example of FIG. 7, the concavo-convex shape 52 has a saw blade shape, and each tooth (i.e., the convex portion) of the saw blade is formed by a first surface 521 on the side of the first light source 2 and a second surface 522 on the side of the irradiation opening 4a. In the example of FIG. 7, the first surface 521 is inclined so as to approach the optical axis AX1 as it goes toward the irradiation opening 4a in the optical axis direction, and the second surface 522 is inclined so as to move away from the optical axis AX1 as it goes toward the irradiation opening 4a. In the concavo-convex shape 52, the first surface 521 and the second surface 522 are alternately continuous. As illustrated in FIG. 7, the length of the first surface 521 and the length of the second surface 522 may be substantially the same. In other words, the first surface 521 and the second surface 522 may be the equal sides of an isosceles triangle in a cross section (e.g., the paper surface of FIG. 7) including the optical axis AX1. Such a concavo-convex shape 52 may have a spiral shape similar to a female screw, or may have a shape in which a plurality of ring shapes are arranged in the optical axis direction. The pitch of the concavo-convex shape 52 is set to, for example, about several millimeters or less.

[0053] Now, on the inner wall of the spacer 32, the reflected and scattered light L11 mainly enters obliquely from the side of the first light source 2. Therefore, on the inner wall of the spacer 32, more reflected and scattered light L11 enters the first surface 521 than the second surface 522. The first surface 521 reflects and scatters the incident reflected and scattered light L11 mainly in an oblique direction opposite to the irradiation opening 4a. Thereby, the number of times the reflected and scattered light L11 reflects and scatters in the housing 4 can be increased, and the reflected and scattered light L11 can be attenuated in the housing 4. Therefore, the possibility that the reflected and scattered light L11 exits from the irradiation opening 4a can be reduced.

[0054] Further, even if the reflected and scattered light L11 enters the second surface 522 from the side of the first light source 2, the reflected and scattered light L11 reflected and scattered by the second surface 522 mainly enters the first surface 521, and is reflected and scattered in an oblique direction toward the first light source 2 side by the first surface 521. Therefore, the possibility that the reflected and scattered light L11 exits from the irradiation opening 4a can be reduced.

[0055] As described above, even when the concavo-convex shape 52 is adopted as the light reduction structure 5, the reflected and scattered light L11 emitted from the irradiation aperture 4a can be reduced. That is, the illumination device 1A can emit the higher-quality first light L1 into the illumination space S1.

[0056] In the example of FIG. 7, although the lengths of the first surface 521 and the second surface 522 are substantially the same, they may be different from each other. FIG. 8 is a diagram schematically showing another example of the concavo-convex shape 52. Also in the example of FIG. 8, the concavo-convex shape 52 is the shape of the inner wall surface of the spacer 32. However, in the example of FIG. 8, the length of the second surface 522 that moves away from the optical axis AX1 as it approaches the irradiation aperture 4a is longer than that of the first surface 521. In the example of FIG. 8, since the first surface 521 is substantially orthogonal to the optical axis AX1, in the cross section including the optical axis AX1, the first surface 521 corresponds to the adjacent side of a right triangle, and the second surface 522 is corresponds to the hypotenuse of the right triangle.

[0057] Such reflected and scattered light L11 also enters the inner wall surface of the spacer 32 mainly from the side of the first light source 2 in an oblique direction. The first surface 521 reflects and scatters the incident reflected and scattered light L11 mainly toward the side opposite to the irradiation aperture 4a. That is, the first surface 521 reflects and scatters the reflected and scattered light L11 mainly in the oblique direction on the side of the first light source 2. Although a part of the reflected and scattered light L11 from the first surface 521 may enter the second surface 522, since the second surface 522 is inclined, most of the reflected and scattered light L11 can be reflected and scattered in the oblique direction on the side of the first light source 2.

[0058] Also, even if the reflected and scattered light L11 from the side of the first light source 2 enters the second surface 522, the reflected and scattered light L11 reflected and scattered by the second surface 522 enters the first surface 521 and is reflected and scattered in the oblique direction on the side of the first light source 2 by the first surface 521.

[0059] As described above, the reflected and scattered light L11 incident on the concavo-convex shape 52 from the side of the first light source 2 can be mainly reflected and scattered in the oblique direction on the side of the first light source 2. Therefore, the possibility of the reflected and scattered light L11 being emitted from the irradiation aperture 4a can be reduced.

[0060] In the above example, although the light reduction structure 5 is located on the inner wall of the spacer 32, it is not necessarily limited to this. FIG. 9 is a cross-sectional view schematically showing a first aspect of the lighting device 1A. In the example of FIG. 9, the light reduction structure 5 is located on the inner wall of the housing 4. The light reduction structure 5 may include a reflection reduction portion 51. According to this, since the reflection of the reflected scattered light L11 incident on the reflection reduction portion 51 is suppressed, the reflected scattered light L11 emitted from the irradiation opening 4a into the illumination space S1 can be reduced.

[0061] The reflection reduction portion 51 may be located on the entire inner wall surface of the housing 4 as illustrated in FIG. 9, or may be located only on a part thereof. For example, the reflection reduction portion 51 may be located only on all or a part of the inner wall of the side wall 41 surrounding the optical axis AX1. For example, the reflection reduction portion 51 is located on the entire circumference of the inner wall of the side wall 41.

[0062] FIG. 10 is a cross-sectional view schematically showing a second aspect of the lighting device 1A. As illustrated in FIG. 10, the light reduction structure 5 located on the inner wall of the housing 4 may have an uneven shape 52. That is, the inner wall of the housing 4 may have the uneven shape 52 as the light reduction structure 5. In this case, the uneven shape 52 may be formed on the entire inner wall surface of the housing 4, or may be formed only on a part thereof. The uneven shape 52 can be formed on at least all or a part of the inner wall surface of the side wall 41. For example, the uneven shape 52 is formed on the entire circumference of the inner wall surface of the side wall 41.

[0063] The reflected scattered light L11 incident obliquely on the uneven shape 52 of the inner wall of the side wall 41 from the side of the first light source 2 is mainly reflected and scattered in the oblique direction toward the side of the first light source 2. Therefore, the reflected scattered light L11 emitted from the irradiation opening 4a into the illumination space S1 can be reduced.

[0064] As described above, the light reduction structure 5, which is the reflection reduction part 51 or the uneven shape 52, may be located at least in part on the inner wall of the housing 4. Specifically, the light reduction structure 5 may be located on the inner wall surface of the side wall 41 between the first emission part 21 of the first light source 2 and the first lens 31, or may be located on the inner wall surface of the side wall 41 between the first lens 31 and the irradiation opening 4a. In a structure where a plurality of first lenses 31 are located, the light reduction structure 5 may be located on the inner wall surface of the side wall 41 between the first lenses 31.

[0065] The light reduction structure 5 is located between the first lens 31 and the first emission part 21, and does not necessarily exist between the first lens 31 and the irradiation opening 4a. Thereby, while reducing glare inside the housing, the irradiation opening 4a can be made of the same white member as the installation location such as the ceiling, for example, to eliminate the presence of lighting. Thereby, the comfort of the user can be further enhanced.

[0066] In the above example, the light reduction structure 5 is located on at least one of the inner wall of the spacer 32 and the inner wall of the housing 4. However, it is not necessarily limited to this. In short, the light reduction structure 5 is exposed in the internal space of the housing 4 and is arranged at a position that does not interfere with the first light L1 that passes through the first lens optical system 3 and forms an image on the image plane IS1. For example, the light reduction structure 5 may be located on the surface of a lens holder (not shown) that holds the lens 31. first It may be located on the surface of a lens holder (not shown) that holds the lens 31.

[0067] Further, the light reduction structure 5 may include both the reflection reduction part 51 and the uneven shape 52. In this case, the reflection reduction part 51 is located on the surface of the uneven shape 52.

[0068] <The Third Embodiment> FIG. 11 is a cross-sectional view schematically showing an example of the configuration of the lighting device 1B according to the third embodiment. The lighting device 1B is different from the lighting device 1 in terms of the specific configuration of the first lens optical system 3. In the lighting device 1B, the first lens optical system 3 includes a plurality of first lenses 31 and constitutes a bilateral telecentric optical system. The bilateral telecentric optical system is an optical system in which the principal ray of the first light L1 is parallel to the optical axis AX1 on the first light source 2 side and the principal ray of the first light L1 is parallel to the optical axis AX1 on the irradiation aperture 4a side. In the example of FIG. 11, the principal rays of the first light L1 emitted from each point of the first emission unit 21 are shown as thick dashed lines.

[0069] The principal ray is a ray passing through the center of the first light L1 in the plane A1 perpendicular to the optical axis AX1 at the diaphragm position. The diaphragm position is, for example, the position where the ratio of the area where the first lights L1 emitted from each point of the first emission unit 21 overlap in the plane A1 is the highest when the plane A1 is moved along the optical axis direction. Here, the first lights L1 emitted from three points on the first emission unit 21 are called the first partial light L1a, the first partial light L1b, and the first partial light L1c, respectively. As illustrated in FIG. 11, the first partial light L1a, the first partial light L1b, and the first partial light L1c overlap with each other in the plane A1 at the diaphragm position and ideally coincide with each other. That is, in the plane A1, the ratio of the area where the first partial lights L1a to L1c overlap with each other is the highest with respect to the entire area of the first light L1.

[0070] As illustrated in FIG. 11, among the rays of the first partial light L1a, the principal ray passing through the center of the first light L1 in the plane A1 is parallel to the optical axis AX1 on both the first light source 2 side and the irradiation aperture 4a side. Similarly, the principal ray of the first partial light L1b is parallel to the optical axis AX1 on both the first light source 2 side and the irradiation aperture 4a side, and the principal ray of the first partial light L1c is parallel to the optical axis AX1 on both the first light source 2 side and the irradiation aperture 4a side.

[0071] In the example of FIG. 11, although three first lenses 31 are schematically shown, the number of the first lenses 31 can be appropriately changed. Further, in the example of FIG. 11, although a biconvex lens is shown as the first lens 31, other lenses such as a concave lens may be appropriately adopted.

[0072] According to this lighting device 1B, the principal rays of the first light L1 irradiated from the irradiation aperture 4a are substantially parallel and hardly spread. According to this, the divergence angle of the first light L1 irradiated from the irradiation aperture 4a can be reduced. Therefore, the first light L1 can be irradiated onto a narrower irradiation area, and the presence of the lighting device 1B can be further reduced.

[0073] <Fourth Embodiment> FIGS. 12 and 13 are cross-sectional views schematically showing an example of the configuration of a lighting device 1C according to the fourth embodiment. The lighting device 1C is different from the lighting device 1 in terms of the presence or absence of a zoom mechanism 6.

[0074] The zoom mechanism 6 zooms, that is, adjusts, the divergence angle of the first light L1 from the irradiation aperture 4a by adjusting the positions of the respective first lenses 31 constituting the first lens optical system 3 on the optical axis AX1. Although the zoom mechanism 6 is not particularly limited, for example, it may have a ball screw mechanism. Such a ball screw mechanism includes a lead screw extending in the optical axis direction, a carriage coupled to the lead screw by a screw action, a lens holder connected to the carriage and holding the first lens 31, and a motor for rotating the lead screw. When the lead screw rotates, the carriage, the lens holder, and the first lens 31 move integrally along the optical axis direction. The motor is controlled by a controller (not shown).

[0075] Further, the housing 4 may be composed of a plurality of cylindrical bodies and may move along the optical axis direction together with each first lens 31. That is, the zoom mechanism 6 may move the first lens 31 and the cylindrical bodies integrally. According to this, the size of the housing 4 in the optical axis direction changes according to the positions of the respective first lenses 31.

[0076] In FIG. 13, the distance D1 between the first emission part 21 of the first light source 2 and the first lens 31, and the distance D2 between two adjacent first lenses 31 are wider than those in the case of FIG. 12. Thereby, the divergence angle of the first light L1 emitted from the irradiation aperture 4a of the illumination device 1C can be made smaller.

[0077] As described above, according to the illumination device 1C, by adjusting the position of each first lens 31 by the zoom mechanism 6, the divergence angle of the first light L1 emitted from the irradiation aperture 4a can be adjusted. Therefore, the size of the irradiation area can be adjusted.

[0078] Note that, since the zoom mechanism 6 adjusts the position of the first lens 31, the numerical aperture of the first lens optical system 3 also changes, and thus the angle θ2 that defines the numerical aperture also changes. Here, the divergence angle θ1 of the first light source 2 is set to be equal to or less than the minimum value within the range that the angle θ2 can take due to the movement of the first lens 31. According to this, even if each first lens 31 moves by the zoom mechanism 6, the first light L1 from the first light source 2 can pass through the effective area of the first lens optical system 3. In other words, the first light L1 from the first light source 2 hardly passes through the edge of the first lens 31. Therefore, the illumination device 1C can emit the first light L1 with high efficiency and high quality into the illumination space S1 regardless of the position of the first lens 31.

[0079] <Fifth Embodiment> FIG. 14 is a cross-sectional view schematically showing an example of the configuration of an illumination device 1D according to the fifth embodiment. The illumination device 1D is different from the illumination device 1 in terms of the presence or absence of the reflection member 7 and the position of the irradiation aperture 4a.

[0080] The reflection member 7 is located inside the housing 4, reflects the first light L1, and changes its traveling direction. The reflection member 7 includes, for example, a mirror or a prism. In the example of FIG. 14, the reflection member 7 is located at a stage subsequent to the first lens optical system 3 in the path of the first light L1. The reflection member 7 reflects the first light L1 that has passed through the first lens optical system 3 toward the irradiation aperture 4a.

[0081] In the example of FIG. 14, the irradiation opening 4a is not formed in the second member 43 of the housing 4, but is formed in the side wall 41. The irradiation opening 4a penetrates the side wall 41 in its thickness direction, connecting the internal space of the housing 4 and the illumination space S1. In the example of FIG. 14, the irradiation opening 4a is formed at a position facing the reflecting member 7 in the radial direction centered on the central axis of the side wall 41. The first light L1 from the reflecting member 7 passes through the irradiation opening 4a and is emitted into the illumination space S1.

[0082] According to such an illumination device 1D, since the traveling direction of the first light L1 can be made different from the traveling direction of the first light L1 by the first light source 2 by the reflecting member 7, the degree of freedom in the installation position of the irradiation opening 4a can be improved.

[0083] Further, in the example of FIG. 14, the reflecting member 7 reflects the first light L1 downward at a substantially right angle in the subsequent stage of the first lens optical system 3. When such an illumination device 1D is provided on the ceiling portion of the illumination space S1, the illumination device 1D can be arranged in the ceiling space in a posture such that the traveling direction of the first light L1 in the first light source 2 is substantially parallel to the horizontal direction. In the example of FIG. 14, a ceiling plate 100 forming the ceiling surface of the illumination space S1 is also shown. An opening 10a penetrating the ceiling plate 100 along the vertical direction is formed in the ceiling plate 100, and the illumination device 1D is arranged above the ceiling plate 100 at a position where the irradiation opening 4a faces the opening 10a.

[0084] In such an illumination device 1D, since the plurality of first lenses 31 of the first lens optical system 3 are arranged along the horizontal direction, although the horizontal size of the illumination device 1D becomes large, the vertical size of the illumination device 1D can be reduced. Therefore, even when the height of the ceiling space is low, the illumination device 1D can be arranged. That is, the illumination device 1D is suitable for installation on the ceiling portion of the illumination space S1.

[0085] FIG. 15 is a cross-sectional view schematically showing another aspect of the lighting device 1D. In the example of FIG. 15, the reflecting member 7 is located between the two first lenses 31 in the path of the first light L1. Hereinafter, the first lens 31 located on the side of the first light source 2 is referred to as the first A lens 31, and the first lens 31 located on the side of the irradiation opening 4a is referred to as the first B lens 31.

[0086] In the example of FIG. 15, the side wall 41 of the housing 4 forms an L-shaped internal space. That is, the side wall 41 extends from the periphery of the first member 42 along the traveling direction of the first light L1, bends at a position corresponding to the reflecting member 7, extends along the traveling direction of the first light L1 from the reflecting member 7, and reaches the periphery of the second member 43. Such a side wall 41 has a shape similar to that of a so-called L-shaped tube. Hereinafter, the portion of the side wall 41 corresponding to the front stage of the reflecting member 7 is referred to as the first portion 411, the portion corresponding to the rear stage of the reflecting member 7 is also referred to as the second portion 412, and the portion connecting the first portion 411 and the second portion 412 is also referred to as the connecting portion 413.

[0087] Between the first light source 2 and the reflecting member 7, a part of the first A lens 31 constituting the first lens optical system 3 is located. The first A lens 31 is located within the first portion 411. Between the reflecting member 7 and the irradiation opening 4a of the second member 43, the remaining first B lens 31 constituting the first lens optical system 3 is located. The first B lens 31 is located within the second portion 412. The reflecting member 7 is located within the connecting portion 413.

[0088] When the lighting device 1D according to such another aspect is arranged on the ceiling portion of the lighting space S1, it can be arranged in the ceiling space in a posture such that the traveling direction of the first light L1 in the first light source 2 is substantially parallel to the horizontal direction. According to this, even if the height of the ceiling space is low, the lighting device 1D can be arranged. Further, according to the lighting device 1D according to another aspect, the second portion 412 can be inserted into the opening 10a of the ceiling board 100. According to this, the size of the lighting device 1D in the ceiling space can be reduced.

[0089] <Sixth Embodiment> FIG. 16 is a cross-sectional view schematically showing an example of the configuration of the lighting device 1E according to the sixth embodiment. The lighting device 1E is different from the lighting device 1 in terms of the presence or absence of the second light source 8, the second lens optical system 9, and the combining element 10. Also, as illustrated in FIG. 16, the housing 4 houses at least the first lens optical system 3, the second lens optical system 9, and the combining element 10. For this reason, the shape of the housing 4 is also different from that of the housing 4 of the lighting device 1.

[0090] The second light source 8 has a second emission portion 81 and emits a second light L2 different from the first light L1 from the first light source 2 from the second emission portion 81. The second light L2 is light having a wavelength range different from that of the first light L1 and is, for example, visible light. An example of the specific configuration of the second light source 8 is the same as that of the first light source 2.

[0091] In the example of FIG. 16, the second light source 8 is also attached to the housing 4. The second light source 8 emits the second light L2 into the internal space of the housing 4. In the example of FIG. 16, the second light source 8 emits the second light L2 along the traveling direction of the first light L1 from the first light source 2. The second light L2 from the second light source 8 also travels while spreading in the same manner as the first light L1.

[0092] The second lens optical system 9 is located inside the housing 4. The second lens optical system 9 is an imaging optical system that forms an image of the second light L2 from the second light source 8 on a virtual image plane on the side opposite to the second light source 8, that is, on the irradiation aperture 4a side. This image plane is also located, for example, inside the irradiation aperture 4a, similar to the image plane IS1. The second lens optical system 9 includes one or more second lenses 91. In the example of FIG. 16, a plurality (here, two) of second lenses 91 are arranged at intervals in the path of the second light L2. A specific example of the second lens 91 is the same as that of the first lens 31.

[0093] In the example of FIG. 16, a set of a second light source 8 and a second lens optical system 9 is arranged in parallel with respect to a set of a first light source 2 and a first lens optical system 3. In the example of FIG. 16, a reflecting member 71 is positioned downstream of the second lens optical system 9, and the reflecting member 71 reflects the second light L2 from the second lens optical system 9 toward the combining element 10. In the example of FIG. 16, the reflecting member 71 is arranged inside the housing 4 at a position above the combining element 10 and facing the combining element 10 in the vertical direction. The reflecting member 71 includes, for example, a mirror or a prism.

[0094] The combining element 10 is an element that combines the first light L1 and the second light L2. For example, the combining element 10 includes a first prism 11, a second prism 12, and a filter film 13. In the example of FIG. 16, the first prism 11 and the second prism 12 have a right-angled isosceles triangular prism shape and are arranged such that their inclined surfaces face each other.

[0095] The filter film 13 is located on the inclined surfaces of the first prism 11 and the second prism 12, reflects the first light L1, and transmits the second light L2. That is, the transmittance of the filter film 13 for the wavelength range of the second light L2 is higher than the transmittance for the wavelength range of the first light L1, and the reflectance of the filter film 13 for the wavelength range of the first light L1 is higher than the reflectance for the wavelength range of the second light L2. Such a filter film 13 can be realized, for example, by a dielectric multilayer film. The dielectric multilayer film has, for example, a structure in which a plurality of dielectric thin films are laminated. As the dielectric, for example, one or more materials among titanium oxide (TiO2), SiO2, niobium pentoxide (Nb2O5), tantalum pentoxide (Ta2O5), and magnesium fluoride (MgF2) are adopted.

[0096] In the example of FIG. 16, the first light L1 passes through the first prism 11 of the combining element 10 and is incident on the filter film 13 at an incident angle of 45 degrees. The first light L1 is reflected by the filter film 13. In the example of FIG. 16, the first light L1 after reflection travels downward along the vertical direction. The second light L2 passes through the second prism 12 and is incident on the filter film 13 at an incident angle of 45 degrees. The second light L2 passes through the filter film 13 and merges with the first light L1 reflected by the filter film 13. That is, behind the filter film 13, the first light L1 and the second light L2 travel together.

[0097] The irradiation opening 4a of the housing 4 is formed at a position where the first light L1 and the second light L2 from the combining element 10 can pass through. In the example of FIG. 16, it is formed at a position facing the combining element 10 in the vertical direction. The first light L1 and the second light L2 from the combining element 10 pass through the irradiation opening 4a of the housing 4 and are emitted into the illumination space S1.

[0098] In such an illumination device 1E, the imaging magnification of the second lens optical system 9 is equal to or less than the ratio of the size of the irradiation opening 4a to the size of the second light L2 at the second emission part 81 of the second light source 8. Therefore, the second light L2 can also pass through the irradiation opening 4a as a spot smaller than the size of the irradiation opening 4a. Therefore, the possibility that the second light L2 is reflected or scattered at the periphery of the irradiation opening 4a can be reduced.

[0099] The imaging magnification of the second lens optical system 9 may be set such that the size of the second light L2 passing through the irradiation opening 4a is smaller than the irradiation opening 4a. According to this, the reflected and scattered light can be further reduced.

[0100] Also, in the illumination device 1E, the divergence angle of the second light L2 at the second emission part 81 is equal to or less than the angle defining the numerical aperture of the second lens optical system 9. According to this, the second light L2 can pass through the effective region of the second lens optical system 9. Therefore, the second light L2 is hardly incident on the edge of the second lens 91, and unnecessary scattering of the second light L2 can be suppressed or avoided.

[0101] Therefore, the lighting device 1E can emit the second light L2 into the illumination space S1 with high efficiency and high quality. Further, since the lighting device 1E emits light including the first light L1 and the second light L2 into the illumination space S1, light in a wider wavelength range can be emitted into the illumination space S1.

[0102] FIG. 17 is a cross-sectional view schematically showing a first aspect of the lighting device 1E. In the example of FIG. 17, the filter film 13 of the merging element 10 transmits the first light L1 and reflects the second light L2. Therefore, in the example of FIG. 17, the irradiation opening 4a of the housing 4 is formed at a position facing the merging element 10 in the left-right direction.

[0103] FIG. 18 is a view schematically showing a second aspect of the lighting device 1E. In the example of FIG. 18, a lens 39 is positioned between the merging element 10 and the irradiation opening 4a of the housing 4. Therefore, the first light L1 and the second light L2 from the merging element 10 are incident on the lens 39. That is, in the example of FIG. 18, the first lens 31 and the lens 39 constitute the first lens optical system 3, and the second lens 91 and the lens 39 constitute the second lens optical system 9. For this reason, the lens 39 can be said to be the first lens 31 and can also be said to be the second lens 91.

[0104] Since the lens 39 is shared by the first lens optical system 3 and the second lens optical system 9, the size and manufacturing cost of the lighting device 1E can be reduced.

[0105] <The Seventh Embodiment> FIG. 19 is a cross-sectional view schematically showing an example of the configuration of a lighting device 1F according to the seventh embodiment, and FIG. 20 is a cross-sectional view showing an enlarged part of the configuration of the lighting device 1F. The lighting device 1F is different from the lighting device 1 in terms of the specific configuration of the housing 4 and the first lens optical system 3. First, an example of the first lens optical system 3 will be described below, and then an example of the housing 4 will be described.

[0106] In the example of FIG. 19, the first lens optical system 3 includes a plurality of first lenses 31. As a specific example, the first lens optical system 3 includes a first A lens 31 and a first B lens 31. Hereinafter, the first A lens 31 is also referred to as the first A lens 31A, and the first B lens 31 is also referred to as the first B lens 31B. The first A lens 31A is located on the first light emitting portion 21 side of the first light source 2 with respect to the first B lens 31B. As shown in FIG. 19, the refractive power of the first A lens 31A located immediately after the first light emitting portion 21 may be greater than the refractive power of the first B lens 31B. Thereby, the first A lens 31A can significantly reduce the degree of spread of the first light L1 at the position closest to the first light emitting portion 21. In the example of FIG. 20, although the first light L1 immediately after the first A lens 31A spreads as it travels toward the first B lens 31B, the angle of spread is significantly smaller than the angle of spread θ1 of the first light L1 incident on the first A lens 31A. For this reason, the size in the width direction perpendicular to the optical axis AX1 of the first B lens 31B can be reduced. In other words, even if the size of the first B lens 31B is reduced, the first light L1 from the first A lens 31A can be appropriately incident on the first B lens 31B. As a result, the size of the illumination device 1F in the width direction can be reduced.

[0107] As shown in FIG. 19, the first A lens 31A has a first surface 31Aa and a second surface 31Ab, and the first B lens 31B has a first surface 31Ba and a second surface 31Bb. The first surface 31Aa is the surface of the first A lens 31A on the first light emitting portion 21 side, and the second surface 31Ab is the surface of the first A lens 31A on the irradiation aperture 4a side. The first surface 31Ba is the surface of the first B lens 31B on the first light emitting portion 21 side, and the second surface 31Bb is the surface of the first B lens 31B on the irradiation aperture 4a side.

[0108] As shown in FIG. 19, the first surface 31Aa of the first A lens 31A may be curved so as to be convex toward the first light emitting portion 21 side, and the second surface 31Ab may be curved so as to be convex toward the irradiation aperture 4a side. The first surface 31Aa and the second surface 31Ab of the first A lens 31A may be curved surfaces without a step. In other words, the first A lens 31A may not be a Fresnel lens. Thereby, scattering or reflection in the first A lens 31A can be reduced. As a result, a comfortable illumination space S1 with less glare can be realized. Also, the curvature of the first surface 31Aa of the first A lens 31A may be smaller than the curvature of the second surface 31Ab. That is, the first surface 31Aa may be flatter than the second surface 31Ab. According to this, the first light L1 from the first light emitting portion 21 can be incident on the first surface 31Aa of the first A lens 31A in a wider range. In other words, the first light L1 from the first light emitting portion 21 can be appropriately incident on the first surface 31Aa of the first A lens 31A.

[0109] Conversely, the curvature of the second surface 31Ab of the first A lens 31A may be larger than the curvature of the first surface 31Aa. If the curvature of the second surface 31Ab is large, the refractive power of the first A lens 31A can be improved. Therefore, the first A lens 31A can significantly reduce the divergence angle of the first light L1. Accordingly, the size of the illumination device 1F in the width direction can be reduced.

[0110] As shown in FIG. 19, the first surface 31Ba of the first B lens 31B may be curved so as to be convex toward the first emission unit 21 side, and the second surface 31Bb may be curved so as to be convex toward the irradiation aperture 4a side. The first surface 31Ba and the second surface 31Bb of the first B lens 31B may be curved surfaces without a step. In other words, the first B lens 31B may not be a Fresnel lens. Thereby, a comfortable illumination space S1 with less glare can be realized. As shown in FIG. 19, the curvature of the first surface 31Aa of the first A lens 31A may be smaller than the curvatures of both the first surface 31Ba and the second surface 31Bb of the first B lens 31B. Also, the curvature of the second surface 31Ab of the first A lens 31A may be larger than the curvatures of both the first surface 31Ba and the second surface 31Bb of the first B lens 31B.

[0111] In addition, when three or more first lenses 31 are arranged, the refractive power of the first lens 31 closest to the first emission unit 21 of the first light source 2 may be the largest. Thereby, the first lens 31 closest to the first emission unit 21 can significantly reduce the divergence angle of the first light L1. Therefore, the size in the width direction of the illumination device 1F can be effectively reduced.

[0112] As shown in FIG. 19, when the refractive power of the first A lens 31A is large, for example, the curvature of the second surface 31Ab of the first A lens 31A is very large . Such a curvature big Increasing the size in the width direction of the first A lens 31A having the second surface 31Ab makes it difficult to manufacture the first A lens 31A. Also, the size of the first A lens 31A along the optical axis AX1 increases, leading to an increase in the size of the illumination device 1F.

[0113] Therefore, as shown in FIG. 19, the size of the first A lens 31A may be smaller than that of the first B lens 31B. That is, the area of the first A lens 31A as viewed along the optical axis AX1 may be smaller than the area of the first B lens 31B. According to this, the manufacture of the first A lens 31A can be facilitated, and the size of the illumination device 1F in the optical axis direction can also be reduced.

[0114] As shown in FIG. 19, in addition to the side wall 41, the first member 42, and the second member 43, the housing 4 may further have a mounting member 44. Also, a second opening (hereinafter simply referred to as an opening) may be formed in the first member 42. )4 b may be formed. The opening 4b penetrates the first member 42 in the optical axis direction. It can also be said that the first member 42 is an opening member having the opening 4b. As will be described later, the first light L1 from the first emission part 21 of the first light source 2 passes through the opening 4b.

[0115] The mounting member 44 is attached to the first member 42 so as to close the opening 4b of the first member 42. The mounting member 44 has, for example, a plate-like shape and is positioned with its thickness direction along the optical axis direction. As shown in FIG. 19, the mounting member 44 may be attached to the surface 42a of the first member 42 on the side opposite to the irradiation opening 4a. The mounting member 44 may be attached to the first member 42 by any attachment method. As an example of a specific attachment method, the mounting member 44 may be attached to the first member 42 by a fixing agent such as an adhesive. Since the mounting member 44 closes the opening 4b, it can also be said to be a lid member.

[0116] The mounting member 44 has a surface 44a, a surface 44b, and a side surface 44c. The surface 44b is the surface of the mounting member 44 on the side of the first member 42. A part of the outer peripheral side of the surface 44b of the mounting member 44 is in contact with the surface 42a of the first member 42 while facing it in the optical axis direction. The surface 44a of the mounting member 44 is the surface opposite to the surface 44b of the mounting member 44. The side surface 44c is a side surface connecting the surface 44a and the surface 44b of the mounting member 44.

[0117] As shown in FIG. 19, the first light source 2 may be located on the surface 44b of the mounting member 44. The first light source 2 is located above a region of the surface 44b of the mounting member 44 that faces the opening 4b of the first member 42 in the optical axis direction. As shown in FIG. 19, a recess in which the first light source 2 is located may be formed in the surface 44b of the mounting member 44.

[0118] The area of the first emission part 21 of the first light source 2 as viewed along the optical axis direction may be smaller than the minimum value of the opening area of the opening 4b of the first member 42. According to this, the first light L1 that spreads and advances from the first emission part 21 can pass through the opening 4b more appropriately.

[0119] As shown in FIGS. 19 and 20, the first A lens 31A may be positioned in the opening 4b of the first member 42. Specifically, as shown in FIG. 20, the opening 4b of the first member 42 may be constituted by a noise removal opening 4ba and a storage opening 4bb. The storage opening 4bb is a space in which the first A lens 31A is stored and is located on the first B lens 31B side with respect to the noise removal opening 4ba. The noise removal opening 4ba communicates with the storage opening 4bb in the optical axis direction, and its opening area is smaller than the opening area of the storage opening 4bb.

[0120] That is, the inner peripheral surface forming the opening 4b of the first member 42 has a stepped shape. Specifically, the inner peripheral surface of the first member 42 has a first inner peripheral surface 421a forming the noise removal opening 4ba, a second inner peripheral surface 42b forming the storage opening 4bb, and a connecting surface 421b connecting the first inner peripheral surface 421a and the second inner peripheral surface 42b. The first inner peripheral surface 421a is closer to the optical axis AX1 than the second inner peripheral surface 42b. For this reason, the opening area of the noise removal opening 4ba is smaller than the opening area of the storage opening 4bb.

[0121] The first member 42 includes an inner peripheral protrusion 421. The inner peripheral protrusion 421 extends toward the optical axis AX1 more than the second inner peripheral surface 42b and surrounds the optical axis AX1. The inner peripheral surface of this inner peripheral protrusion 421 corresponds to the first inner peripheral surface 421a, and the surface on the first A lens 31A side of the inner peripheral protrusion 421 corresponds to the connecting surface 421b. The second inner peripheral surface 42b of the first member 42 may be in contact with the side surface of the first A lens 31A. The side surface of the first A lens 31A is a surface connecting the periphery of the first surface 31Aa and the periphery of the second surface 31Ab. The first A lens 31A may be fitted into the storage opening 4bb of the first member 42.

[0122] The first light L1 from the first light-emitting portion 21 of the first light source 2 passes through the noise removal aperture 4ba and enters the first lens optical system 3 (specifically, the first A lens 31A). That is, the aperture 4b (specifically, the noise removal aperture 4ba) of the first member 42 allows the first light L1 to pass through to the first lens optical system 3 side. Conversely, noise light (hereinafter also referred to as shielding light) with a lower intensity traveling in the outer region than the first light L1 is blocked by the first member 42. In the example of FIG. 20, the first inner peripheral surface 421a of the noise removal aperture 4ba is inclined with respect to the optical axis AX1. Specifically, the first inner peripheral surface 421a is inclined such that the aperture area of the noise removal aperture 4ba increases as it faces the first light-emitting portion 21 side. In other words, the first inner peripheral surface 421a of the noise removal aperture 4ba is inclined so as to move away from the central axis of the aperture 4b (here, the optical axis AX1) as it faces the first light-emitting portion 21 side. Since the first light-emitting portion 21 is located near the noise removal aperture 4ba, most of the shielding light from the first light-emitting portion 21 enters the first inner peripheral surface 421a of the noise removal aperture 4ba. The shielding light is, for example, reflected or scattered by the first inner peripheral surface 421a of the noise removal aperture 4ba and travels to the side opposite to the first A lens 31A, or a part of it is absorbed by the first member 42.

[0123] As described above, the first light L1 output from the first light-emitting portion 21 passes through the noise removal aperture 4ba, and the shielding light outside it is blocked by the first member 42. Therefore, the possibility of unnecessary reflected and scattered light being emitted from the irradiation aperture 4a can be reduced. Thus, a comfortable lighting space S1 with less glare can be realized.

[0124] Also, in the above example, the first A lens 31A is located in the aperture 4b of the first member 42 that is located immediately after the first light-emitting portion 21. Specifically, the first A lens 31A is located in the accommodation aperture 4bb that is immediately after the noise removal aperture 4ba. Therefore, the distance between the first light-emitting portion 21 and the first A lens 31A can be narrowed. Thus, most of the first light L1 from the first light-emitting portion 21 can be made to enter the first A lens 31A.

[0125] Next, a mechanism for holding the first lens 31A will be described. As shown in FIG. 20, the housing 4 may further include an inner housing 45. The inner housing 45 can function as a lens holder for holding the first lens 31A together with the first member 42. The inner housing 45 is located between the first lens 31A and the first lens 31B. The peripheral portion of the first lens 31A is held in a state of being sandwiched between the inner peripheral protrusion 421 of the first member 42 and the inner housing 45 in the optical axis direction. That is, the inner peripheral protrusion 421 of the first member 42 is in contact with the peripheral portion of the first surface 31Aa of the first lens 31A, and the inner housing 45 is in contact with the peripheral portion of the second surface 31Ab of the first lens 31A.

[0126] As shown in FIG. 20, the inner housing 45 may include a pressing member 451 and a side wall 452 and so on. The pressing member 451 is located on the side of the first lens 31B with respect to the first member 42. The pressing member 451 has a plate-like shape and is positioned in a posture in which its thickness direction is along the optical axis direction. The pressing member 451 faces the first member 42 in the optical axis direction. An opening 45a is formed in the central portion of the pressing member 451. The peripheral portion of the opening 45a in the pressing member 451 is in contact with the second surface 31Ab of the first lens 31A.

[0127] In the example of FIG. 20, the first light L1 travels while spreading inside the first lens 31A. Therefore, as shown in FIG. 20, the opening area of the opening 45a of the pressing member 451 may be larger than the opening area of the noise removal opening 4ba of the first member 42. According to this, while the first member 42 and the pressing member 451 appropriately sandwich and hold the first lens 31A, the first light L1 can be more effectively passed through the opening 45a of the pressing member 451.

[0128] Also, as shown in FIG. 20, the inner peripheral surface forming the opening 45a of the pressing member 451 may have a first inclined surface 451a and a second inclined surface 451b. The first inclined surface 451a is in contact with the second surface 31Ab of the first A lens 31A and has a shape along the second surface 31Ab. Therefore, the first inclined surface 451a is inclined so as to move away from the optical axis AX1 as it approaches the first light emitting portion 21 of the first light source 2 in the optical axis direction. The second inclined surface 451b is located on the first B lens 31B side with respect to the first inclined surface 451a and is connected to the first inclined surface 451a. The second inclined surface 451b is inclined in the opposite direction to the first inclined surface 451a. That is, the second inclined surface 451b is inclined so as to approach the optical axis AX1 as it approaches the first inclined surface 451a in the optical axis direction. In other words, the second inclined surface 451b is inclined so as to move away from the optical axis AX1 as it approaches the irradiation opening 4a.

[0129] According to this structure, while increasing the thickness of the pressing member 451, the opening area of the opening 45a can be increased. Therefore, while improving the amount of light of the first light L1 passing through the opening 45a, the strength of the pressing member 451 can be improved. Moreover, in the above example, since the second inclined surface 451b is inclined with respect to the optical axis AX1, the first light L1 transmitted through the first A lens 31A is less likely to enter the second inclined surface 451b. Therefore, unnecessary scattering and reflection of the first light L1 can be reduced. For this reason, the possibility that unnecessary reflected scattered light is emitted from the irradiation opening 4a can be reduced.

[0130] The side wall of the inner housing 45 452 has a cylindrical shape surrounding the optical axis AX1 and extends from the outer peripheral edge of the pressing member 451 toward the first B lens 31B side. The side wall 452 inner wall surface is located closer to the optical axis AX1 than the side surface of the first B lens 31B. The side wall 452 outer wall surface and the side surface of the first B lens 31B may be in contact with the inner wall surface of the side wall 41. The side wall of the inner housing 45 452The edge on the side of the first B lens 31B may be in contact with the peripheral portion of the first surface 31Ba of the first B lens 31B. According to this, the inner housing 45 can also function as a spacer that determines the distance between the first A lens 31A and the first B lens 31B. That is, the inner housing 45 can exhibit the same function as the spacer 32 in FIG. 6, for example.

[0131] Next, the properties of the mounting member 44 will be described. The thermal conductivity of the mounting member 44 may be higher than the thermal conductivity of other parts of the housing 4. For example, a metal material with high thermal conductivity is applied to the material of the mounting member 44. Examples of this metal material include copper (Cu), aluminum (Al), magnesium (Mg), gold (Au), silver (Ag), iron (Fe), chromium (Cr), cobalt (Co), beryllium (Be), molybdenum (Mo), tungsten (W), or alloys. On the other hand, various synthetic resins may be applied as the material of other parts of the housing 4 (for example, the first member 42).

[0132] When the thermal conductivity of the mounting member 44 is high, the first light source 2 can be cooled by the mounting member 44. Such a mounting member 44 can function as a so-called heat sink. Thereby, the degree to which the first light source 2 deteriorates due to heat can be reduced. For example, when the first light source 2 includes the wavelength conversion member 23 (see also FIG. 1), the wavelength conversion member 23 can deteriorate due to heat. When the thermal conductivity of the mounting member 44 is high, the degree to which the wavelength conversion member 23 deteriorates due to heat can be reduced. When the first light source 2 includes the wavelength conversion member 23, the thermal conductivity of the mounting member 44 may be higher than the thermal conductivity of the wavelength conversion member 23. Also, the mounting member 44 may be joined to the wavelength conversion member 23. According to this, the mounting member 44 can cool the wavelength conversion member 23 more effectively.

[0133] As described above, the lighting devices 1, 1A to 1F have been described in detail. However, all of the above descriptions are illustrative in all aspects, and the lighting devices 1, 1A to 1F are not limited thereto. Innumerable variations not illustrated can be assumed without departing from the scope of this disclosure. Each configuration described in each of the above embodiments and each variation can be appropriately combined or omitted as long as they do not conflict with each other.

[0134] Needless to say, all or part of each of the above embodiments and various variations can be appropriately combined within a non - conflicting range.

Explanation of Reference Numerals

[0135] 1 Lighting device 2 First light source 21 First emission part 3 First lens optical system 31 First lens 31, 31A First A lens 31Aa First surface 31Ab Second surface 31, 31B First B lens 39 Lens 4 Housing 41 Opening member (first member) 411 First part 412 Second part 413 Connecting part 44 Mounting member 45 Inner housing 451 Pressing member 451a First inclined surface 451b Second inclined surface 4a Opening (irradiation opening) 4b Second opening (opening) 7 Reflective member 8 Second light source 81 Second emission part 9 Second lens optical system 91 Second lens zu IS1 Image plane L1 First light L2 Second light L11 Reflective scattered light θ1 Divergence angle

Claims

1. A housing having an opening, A first light source having a first emitting portion for emitting a first light into the internal space of the housing, In the path of the first light, including at least one first lens located between the first emitting portion and the opening of the housing, the first lens optical system for imaging the first light from the first emitting portion on a virtual image plane on the opening side and emitting the first light from the opening Comprising, The housing includes an opening member having a second opening where the first lens is located, and a mounting member attached in a state of closing the second opening with respect to the surface of the opening member on the side opposite to the opening, The first emitting portion is located in a region of the mounting member facing the second opening, a lighting device.

2. The lighting device according to Claim 1, The lighting device, wherein light rays on both outer sides of the first light are emitted from the opening so as not to contact the housing in the space from the first lens to the opening.

3. The lighting device according to Claim 1 or Claim 2, The lighting device, wherein the imaging magnification of the first lens optical system is not more than the ratio of the size of the opening to the size of the first light at the first emitting portion.

4. The lighting device according to Claim 1 or Claim 2, The first emitting portion includes a wavelength conversion member, The lighting device, wherein the first light is fluorescence emitted from the wavelength conversion member.

5. The lighting device according to Claim 1 or Claim 2, The lighting device, wherein the first lens has a curved surface with a continuous surface.

6. The lighting device according to Claim 1 or Claim 2, The lighting device, wherein the orientation angle of the light emitted from the opening is less than 60°.

7. The lighting device according to Claim 1 or Claim 2, The lighting device, wherein the distance from the first emitting portion to the opening is greater than the inner diameter of the housing.

8. The lighting device according to Claim 1 or Claim 2, The at least one first lens includes a first A lens and a first B lens, The lighting device, wherein the first A lens and the first B lens are arranged side by side in the optical axis direction of the first light.

9. The lighting device according to Claim 8, The lighting device, wherein between the first A lens and the first B lens, the light diameter of the first light becomes smaller than the light diameter passing through the first A lens and the first B lens.

10. The lighting device according to Claim 1 or Claim 2, The at least one first lens includes a first A lens, a first B lens, and a first C lens, The first A lens, the first B lens, and the first C lens are arranged along the optical axis direction of the first light, and are lighting devices.

11. A housing having an opening, A first light source having a first emitting portion that emits first light into the internal space of the housing, In the path of the first light, it includes at least one first lens located between the first emitting portion and the opening of the housing, and forms an image of the first light from the first emitting portion on a virtual image plane on the opening side, and emits the first light from the opening. A first lens optical system Comprising, The at least one first lens includes a first A lens and a first B lens, The first A lens and the first B lens are arranged along the optical axis direction of the first light, The first A lens is located on the first emitting portion side with respect to the first B lens, The refractive power of the first A lens is greater than the refractive power of the first B lens, and is a lighting device.

12. The lighting device according to claim 11, The size of the first B lens is larger than the size of the first A lens, and is a lighting device.

13. The lighting device according to claim 1 or claim 2, The first lens has a first surface on the first emitting portion side and a second surface on the opening side, The curvature of the first surface is smaller than the curvature of the second surface, and is a lighting device.

14. The lighting device according to claim 1 or claim 2, The divergence angle of the first light emitted from the opening is smaller than the divergence angle of the first light emitted from the first emitting portion, and is a lighting device.

15. The lighting device according to claim 1 or claim 2, The image plane is located at the opening, and is a lighting device.

16. The lighting device according to claim 1 or claim 2, The lighting device further includes a light reduction structure that absorbs reflected and scattered light when the first light is reflected or scattered in the internal space of the housing.

17. The lighting device according to claim 1 or claim 2, The lighting device further includes a light reduction structure that reflects or scatters the reflected and scattered light when the first light is reflected or scattered in the internal space of the housing to the first emitting portion side.

18. The lighting device according to claim 17, The lighting device, wherein the light reduction structure has an uneven shape in a cross section including the optical axis of the first light.

19. A housing having an opening, a first light source having a first emission unit that emits first light into the internal space of the housing, a first lens optical system including at least one first lens positioned between the first emission unit and the opening of the housing in the path of the first light, the first lens optical system imaging the first light from the first emission unit on a virtual image plane on the opening side and emitting the first light from the opening, a light reduction structure that is located in the internal space of the housing and where reflected and scattered light of the first light is incident, and that reflects or scatters the reflected and scattered light toward the first emission unit side and comprising the light reduction structure having an uneven shape in a cross section including the optical axis of the first light, the uneven shape having a shape in which concave portions and convex portions are arranged alternately in the cross section the convex portion having a first surface and a second surface on the opening side of the first surface, the lighting device, wherein in the cross section, the length of the second surface is equal to or greater than the length of the first surface.

20. The lighting device according to claim 16, wherein the light reduction structure is located on the inner wall of the housing.

21. The lighting device according to claim 16, wherein the at least one first lens includes a first A lens and a first B lens, the first lens optical system further including a spacer positioned between the first A lens and the first B lens and defining a distance between the first A lens and the first B lens, the lighting device, wherein the light reduction structure is located on the inner wall of the spacer.

22. The lighting device according to claim 1 or claim 2, wherein the first lens optical system includes a double-sided telecentric optical system.

23. The lighting device according to claim 1 or claim 2, further comprising a zoom mechanism that moves the at least one first lens along the optical axis of the first light.

24. A housing having an opening, a first light source having a first emission unit that emits first light into the internal space of the housing, a first lens optical system including at least one first lens positioned between the first emission unit and the opening of the housing in the path of the first light, the first lens optical system imaging the first light from the first emission unit on a virtual image plane on the opening side and emitting the first light from the opening, a reflecting member that is located within the housing and reflects the first light toward the opening A lighting device comprising

25. The lighting device according to claim 24, wherein the at least one first lens includes a first A lens and a first B lens, and the housing has a first part for housing the first A lens, a second part for housing the first B lens and having the opening, and a connecting part for connecting the first part and the second part and the reflecting member is located in the connecting part and reflects the first light from the first A lens toward the first B lens, wherein the opening is formed at a position through which the first light from the first B lens passes. A lighting device.

26. A housing having an opening, a first light source having a first emitting part for emitting first light into the internal space of the housing, at least one first lens located between the first emitting part and the opening of the housing in the path of the first light, and a first lens optical system for forming an image of the first light from the first emitting part on a virtual image plane on the opening side and emitting the first light from the opening, a second light source having a second emitting part for emitting second light different from the first light into the internal space of the housing, at least one second lens located between the second emitting part and the opening in the path of the second light, and a second lens optical system for forming an image of the second light from the second emitting part on a virtual image plane on the opening side, and a combining element located in the housing for combining the first light and the second light A lighting device comprising

27. The lighting device according to claim 26, wherein a lens located between the combining element and the opening and shared by the first lens optical system and the second lens optical system is included. A lighting device.

28. The lighting device according to claim 1 or claim 2, wherein an inner peripheral surface forming the second opening of the opening member has a portion inclined so that an opening area increases as it approaches the first emitting part. A lighting device.

29. The lighting device according to claim 1 or claim 2, wherein the housing further includes an inner housing that sandwiches a peripheral edge portion of the first lens together with the opening member, the first lens has a first surface on the first emitting part side and a second surface on the opening side, the opening member is in contact with a peripheral edge portion of the first surface of the first lens, and the inner housing includes a pressing member The pressing member has a first inclined surface that contacts the peripheral edge of the second surface of the first lens, and a second inclined surface that is located closer to the opening side than the first inclined surface. The second inclined surface is inclined so as to be away from the optical axis of the first lens as it approaches the opening. Lighting device. **Claim 30**: A lighting device according to claim 1 or claim 2, wherein the heat conductivity of the mounting member is higher than the heat conductivity of other parts of the housing. Lighting device.

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