Lighting device

Abstract

To improve the glare-free performance of lighting devices. [Solution] The lighting device 1 comprises a light source 10, a cylindrical reflector 20 that controls the light emitted from the light source 10, and a cylindrical cone 30 provided on the opposite side of the reflector 20 from the light source 10 in the axial direction. The reflector 20 expands in diameter from the light inlet 21 towards the light outlet 22 such that its inner diameter is maximized at the light outlet 22. The reflector 20 and the cone 30 are configured such that the light emitted from the light outlet 22 passes through the cylinder of the cone 30 without substantially hitting the inner surface of the cone 30.

Description

[Technical Field]

[0001] This disclosure relates to a lighting device, and more particularly to a lighting device comprising a light control member and a cone. [Background technology]

[0002] Conventionally, ceiling-recessed lighting devices equipped with a light control element and a cone, used as so-called downlights, are widely known. The light control element is, for example, a cylindrical reflector that reflects light emitted from a light source and guides it into the cone. Glareless downlights have also been proposed, designed to prevent glare by narrowing the light distribution range (see, for example, Patent Documents 1 and 2). In glareless downlights, the cone functions as an auxiliary reflector that reflects light hitting its inner surface directly downwards, and the inner surface is mirror-finished. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Patent No. 6817553 [Patent Document 2] Patent No. 6356363 [Overview of the Initiative] [Problems that the invention aims to solve]

[0004] Glareless downlights can reduce glare compared to conventional downlights, but further improvements in glare-free performance are needed. Our research has shown that the lighting devices disclosed in Patent Documents 1 and 2 cannot achieve sufficient glare-free performance. Conventional lighting devices, including those described in Patent Documents 1 and 2, still have considerable room for improvement in terms of glare-free performance. [Means for solving the problem]

[0005] The lighting device according to the present disclosure includes a light source, a light control member that controls the light emitted from the light source, and a cone provided on the side opposite to the light source with the light control member interposed therebetween, and the cone expands as it moves away from the light control member. The light control member has a light incident port on the light source side and a light emission port on the cone side, and expands from the light incident port toward the light emission port so that the distance between the inner surfaces facing each other at the light emission port is maximized. The light control member and the cone are configured such that the light emitted from the light emission port passes through the inside of the cone without substantially hitting the cone.

Advantages of the Invention

[0006] According to the lighting device of the present disclosure, excellent glare-free performance can be realized.

Brief Description of the Drawings

[0007] [Figure 1] It is a perspective view of a lighting device as an example of an embodiment seen from above. [Figure 2] It is a perspective view of a lighting device as an example of an embodiment seen from below. [Figure 3] It is an exploded perspective view of a lighting device as an example of an embodiment. [Figure 4] It is an axial cross-sectional view of a lighting device as an example of an embodiment cut along a plane including the optical axis. [Figure 5] It is a cross-sectional view for explaining the structure of the light control member and the cone. [Figure 6] It is a bottom view of the light control member. [Figure 7] It is a view showing a modified example of the light control member. [Figure 8] It is a view showing a modified example of the cone. [Figure 9] It is a perspective view of a lighting device as another example of an embodiment seen from above.

Modes for Carrying Out the Invention

[0008] Hereinafter, embodiments of the lighting device according to this disclosure will be described in detail with reference to the drawings. The embodiments described below are merely examples, and this disclosure is not limited to these embodiments. Furthermore, forms that are obtained by selectively combining the multiple embodiments and modifications described below are included in this disclosure.

[0009] Figures 1 and 2 are perspective views of a lighting device 1, which is an example of an embodiment.

[0010] As shown in Figures 1 and 2, the lighting device 1 comprises a light source 10 (see Figure 3, etc., described later), a cylindrical reflector 20 that controls the light emitted from the light source 10, and a cylindrical cone 30 provided on the side of the reflector 20 opposite to the light source 10 in the axial direction. The reflector 20 has a light inlet 21 (see Figure 3, etc., described later) which is an opening on the light source 10 side, and a light outlet 22 which is an opening on the cone 30 side, and is a light control member that reflects the light from the light source 10 that enters from the light inlet 21 and passes through the cylinder toward the light outlet 22. The cone 30 is a cylindrical body with a larger diameter than the reflector 20, and has a first opening 31 (see Figure 3, etc., described later) on the reflector 20 side, and a second opening 32 on the opposite side of the first opening 31.

[0011] Lighting device 1 is suitable for ceiling-recessed lighting devices, so-called downlights, installed in the ceilings of buildings. Lighting device 1 is installed on the ceiling, for example, with most of the device inserted into a recessed hole in the ceiling panel, and with the second opening 32 of the cone 30 facing vertically downward. As will be described in more detail later, the reflector 20 expands in diameter from the light inlet 21 to the light outlet 22 so that its inner diameter is maximized at the light outlet 22. The reflector 20 and the cone 30 are configured such that the light emitted from the light outlet 22 passes through the cylinder of the cone 30 without substantially hitting the cone 30.

[0012] In this specification, "the light emitted from the light output port 22 of the reflector 20 substantially does not hit the cone 30" means that the light controlled as designed by the reflector 20, etc., does not hit the cone 30. On the other hand, unless the specularity of the reflector 20 is 100%, even a reflector made of a rotating body with a perfectly circular cross-section will generate unintended diffuse reflection components. In the lighting device 1, most of the light emitted from the light output port 22 of the reflector 20 does not hit the cone 30. In other words, all light except for the diffuse reflection components does not hit the cone 30. The inner surface 30A of the cone 30 is dimly illuminated by the diffuse reflection components, but in this case, it is preferable because it can suppress the contrast between the installation surface of the lighting device 1 and the cone 30 from becoming excessive. The lighting device 1 is designed assuming that a certain amount of diffuse reflection components will occur.

[0013] The lighting device 1 is mounted on a horizontal ceiling, but it can also be mounted on a ceiling that is inclined with respect to the horizontal and vertical directions. For the sake of explanation, in the following, the light source 10 side of the lighting device 1 may be referred to as "upper" and the cone 30 side as "lower". The ceiling on which the lighting device 1 is mounted can be any part that demarcates the upper part of a building space, and is not limited to, for example, the ceiling of an interior room, but may also be the ceiling of an entrance porch, terrace, etc. The lighting device according to this disclosure may be mounted on the ceiling in a form other than ceiling recess, and may be applied to, for example, spotlights, down ceiling lights, etc.

[0014] Since the lighting device 1 is designed so that light does not shine on the cone 30, when looking up at the lighting device 1 from below, if the angle is such that the inner surface 20A of the reflector 20 is not visible, no glare will be felt. The lighting device 1 is configured such that the inner surface 20A of the reflector 20 is not visible at an elevation angle of 23° or less, more preferably 30° or less. Here, the elevation angle refers to the angle between the ceiling surface and the user's line of sight when looking up at the lighting device 1 installed on the ceiling.

[0015] Conventional glare-free downlights are designed to cause specular reflection of light by mirroring the inner surface of the cone, as excessive light hitting the cone and causing diffuse reflection results in glare. In contrast, lighting device 1 is configured so that a large amount of light emitted from the light outlet 22 of the reflector 20 does not hit the cone 30, thus eliminating the problem of glare caused by diffuse reflection of the cone 30. Therefore, there is no need to mirror-finish the inner surface 30A of the cone 30. As will be explained in more detail later, the inner surface 30A of the cone 30 can be freely designed to match the ceiling design.

[0016] The lighting device 1 further includes a housing 40 that houses the light source 10 and the reflector 20, and a heat dissipation member 50 for suppressing the temperature rise of the light source 10. The housing 40 is a cylindrical body that is slightly larger than the reflector 20, and has a large-diameter portion 41 located on the light source 10 side and a small-diameter portion 42 located on the cone 30 side. The heat dissipation member 50 has a base portion 51 fixed to the large-diameter portion 41 of the housing 40 and heat dissipation fins 52 erected on the base portion 51. The lighting device 1 also includes a frame 60 to which a mounting spring 65 is fixed, and a connecting member 70 for fixing the cone 30 and the frame 60 to the housing 40.

[0017] The lighting device 1 has a structure in which the axial directions of the reflector 20, cone 30, and housing 40 coincide, and it extends long in that axial direction (vertical direction). The reflector 20, cone 30, and housing 40 are assembled so that their central axes coincide. The lighting device 1 has a structure in which the heat dissipation member 50, housing 40, connecting member 70, and frame 60 are arranged from top to bottom. The light source 10, reflector 20, and cone 30, which are installed inside the lighting device 1, are arranged in this order from top to bottom. Because the outer diameters of the heat dissipation member 50 and frame 60 are large, and the outer diameter of the small-diameter portion 42 of the housing 40 is small, the lighting device 1 has an external shape that is constricted in the middle in the vertical direction.

[0018] The reflector 20 is a light control component that controls the light distribution. The inner surface 20A of the reflector 20 functions as a reflective surface that reflects light from the light source 10 and is finished to a mirror surface. When the lighting device 1 is viewed from below, the light output port 22 and the inner surface 20A of the reflector 20 are visible. When the lighting device 1 is turned off, the light input port 21 of the reflector 20 is also visible when the lighting device 1 is viewed from directly below. The reflector 20 expands in diameter from the light input port 21 towards the light output port 22 so that its inner diameter is at its maximum at the light output port 22. The inner diameter of the reflector 20 is at its minimum at the light input port 21.

[0019] The cone 30 is a cylindrical cover positioned below the reflector 20 and forms the lower surface of the lighting device 1 visible to the user. That is, the cone 30 does not function as a reflector like the cones of conventional lighting devices, but functions solely as a cover that covers the gap between the ceiling plate and the reflector 20. When the lighting device 1 is viewed from below, the second opening 32 and the inner circumferential surface 30A of the cone 30 are visible, and it has a shape that widens in diameter as it moves away from the reflector 20. Similar to the reflector 20, the cone 30 widens in diameter from the first opening 31 to the second opening 32, with the inner diameter being largest at the second opening 32.

[0020] The housing 40 holds the reflector 20 inside the cylinder. The cone 30, heat dissipation member 50, and frame 60 are fixed to the housing 40. The housing 40 has a flange 43 that protrudes radially outward at the upper end of the large diameter portion 41, and the heat dissipation member 50 is screwed to this flange 43. It can also be said that the flange 43 is fixed to the heat dissipation member 50. The small diameter portion 42 of the housing 40 has a pair of protrusions 44 that protrude radially outward, to which the first connecting portion 71 of the connecting member 70 is screwed. Since the cone 30 and frame 60 are fixed to the connecting member 70, the cone 30 and frame 60 are fixed to the housing 40 via the connecting member 70.

[0021] The heat dissipation member 50 has a base portion 51 formed in a substantially disc shape and a plurality of heat dissipation fins 52 erected on the base portion 51. As will be described in detail later, the light source 10 is fixed to the base portion 51 inside the cylinder of the housing 40. In this case, it is easy to transfer the heat generated by the light source 10 to the heat dissipation fins 52, and excellent heat dissipation can be ensured. The plurality of heat dissipation fins 52 are formed in a plate shape, extend perpendicularly to the base portion 51, and are arranged substantially parallel to each other. The height (vertical length) of the heat dissipation fins 52 is, for example, 40% to 60% of the height of the lighting device 1. The shape, number, and dimensions of the heat dissipation fins 52 can be appropriately changed according to the amount of heat generated by the light source 10, etc.

[0022] The frame 60 is a ring-shaped member positioned to cover a portion of the outer surface of the cone 30, and has a substantially cylindrical cylindrical wall 61 and a flange 62 that protrudes radially outward from the lower end of the cylindrical wall 61. The flange 62 is positioned below the ceiling panel and covers the periphery of the recessed hole in the ceiling panel. Mounting springs 65 are fixed to the outer surface of the cylindrical wall 61. The lighting device 1 is fixed to the ceiling by the mounting springs 65 contacting the area around the recessed hole in the ceiling panel in the space above the ceiling. For example, four mounting springs 65 are provided at equal intervals in the circumferential direction of the frame 60.

[0023] The connecting member 70, like the frame 60, is a ring-shaped member positioned to cover a portion of the outer surface of the cone 30, and has a first connecting portion 71 fixed to a protrusion 44 of the housing 40 and a second connecting portion 72 fixed to the cone 30 (see Figure 3, described later). The cone 30 is fixed to the housing 40 via the connecting member 70 by these two connecting portions. In this embodiment, the frame 60 is also fixed to the connecting member 70 using a screw 66 for fixing the mounting spring 65 (see Figure 4, described later).

[0024] Figure 3 is an exploded perspective view of the lighting device 1.

[0025] As shown in Figure 3, the lighting device 1 includes a light source 10 positioned above the reflector 20. The light source 10 has a substrate 11 and a light-emitting unit 12 mounted on the substrate 11, and is held in a holder 16 with the light-emitting unit 12 facing toward the reflector 20. The light source 10 held in the holder 16 is fixed to the base 51 of the heat dissipation member 50 using a fixing member 17 that holds the substrate 11. Preferably, the surface of the substrate 11 opposite to the light-emitting unit 12 is in contact with the lower surface of the base 51, either directly or via a heat dissipation sheet, heat dissipation grease, etc. The lower surface of the base 51 refers to the surface opposite to the upper surface on which the heat dissipation fins 52 are formed.

[0026] For example, a printed circuit board with metal wiring formed in a predetermined pattern is used for the substrate 11. The light-emitting section 12 preferably includes an LED as a light-emitting element. A suitable example of an LED is a COB (Chip on board) type light-emitting diode device for illumination. The LED is mounted, for example, in the center of the surface of a substantially square substrate 11, forming a circular light-emitting section 12 in plan view.

[0027] As described above, the light source 10 is housed in the housing 40 together with the reflector 20. The housing 40 is a cylindrical body with a large step formed in the axial center, and has a large diameter portion 41 including a flange 43 to which the heat dissipation member 50 is fixed, and a small diameter portion 42 including a protrusion 44 to which the first connecting portion 71 of the connecting member 70 is fixed. The housing 40 houses the entire reflector 20. An annular retaining ring 45 for fixing the reflector 20 is provided inside the cylinder of the large diameter portion 41. The retaining ring 45 is screwed to the bottom of the large diameter portion 41 with a part of the reflector 20 on the light inlet 21 side passing through a hole in the ring, fixing the reflector 20 so that it does not move inside the housing 40.

[0028] The reflector 20 is a cylindrical body whose inner and outer diameters expand axially from one end to the other. However, flanges are formed on the outer surface of the reflector 20 at two locations separated in the axial direction, projecting radially outward. The opening at one axial end of the reflector 20 becomes the light inlet 21 into which light from the light source 10 enters, and the opening at the other axial end becomes the light outlet 22, which is located inside the cylinder of the cone 30 and from which light is emitted. The first flange 23 is formed on the light inlet 21 side of the axial center of the reflector 20 and is pressed down from above by the retaining ring 45. The second flange 24 is formed on the light outlet 22 side of the axial center and is placed on a stepped portion 46 (see Figure 4 below) formed inside the cylinder of the housing 40. As a result, the reflector 20 is held inside the cylinder of the housing 40.

[0029] The cone 30, like the reflector 20, is a cylindrical body whose inner and outer diameters expand axially from one end to the other, with a greater degree of expansion axially toward the other end than the reflector 20. The opening at one axial end of the cone 30 becomes the first opening 31 through which light enters from the reflector 20, and the opening at the other axial end becomes the second opening 32. The second opening 32 is the light output port of the lighting device 1. Two locking portions 33 are formed on the outer circumferential surface of the cone 30, aligned radially. The cone 30 is fixed to the connecting member 70 by the second connecting portion 72 of the connecting member 70 catching on the locking portions 33.

[0030] As described above, the connecting member 70 is a ring-shaped member for fixing the cone 30 and the frame 60 to the housing 40, and has a substantially cylindrical base 71. The base 71 has a shape in which the lower part is slightly smaller in diameter than the upper part. The smaller diameter lower part of the base 71 is inserted into the cylindrical wall 61 of the frame 60 and fixed to the frame 60 using a screw 66 that fixes the mounting spring 65. It is also possible to integrate the frame 60 and the connecting member 70 and apply the structure of the connecting member 70 to the frame 60.

[0031] The base portion 71 is provided with two first connecting portions 71 arranged radially to the connecting member 70. The first connecting portions 71, for example, protrude upward from the base portion 71 and have a screw insertion hole at their upper end. The first connecting portions 71 are fixed to the protrusion 44 of the housing 40 using screws. The base portion 71 is also provided with two second connecting portions 72 arranged radially to the connecting member 70. The second connecting portions 72 protrude downward from the base portion 71 and are bent so that their lower ends catch on the locking portion 33 of the cone 30.

[0032] Figure 4 is an axial cross-sectional view of the lighting device 1, cut by a plane containing the optical axis α. Figure 4 shows the lighting device 1 installed in the recessed hole 101 of the ceiling panel 100. The optical axis α is a hypothetical ray that represents the luminous flux emitted from the light source 10, and extends straight up and down from the center of the light-emitting part 12.

[0033] As shown in Figure 4, the lighting device 1 has the reflector 20 and cone 30 arranged vertically with respect to the light-emitting part 12 of the light source 10 so that the light emitted from the light-emitting part 12 of the light source 10 enters the cylinder of the reflector 20 and cone 30. The light source 10 is fixed to the heat dissipation member 50 with the light-emitting part 12 facing the reflector 20, and the reflector 20 and cone 30 are arranged so that the optical axis α of the light-emitting part 12 and their respective central axes coincide. The reflector 20 is positioned below the light source 10 with a predetermined gap between them. The predetermined gap is set to a range that allows the light from the light source 10 to be introduced into the light entry port 21 of the reflector 20 without significant loss.

[0034] The lighting device 1 includes a lens 15 positioned between the light source 10 and the reflector 20, i.e., in the predetermined gap. The lens 15 efficiently guides the light emitted from the light-emitting part 12 to the light entry port 21 of the reflector 20. Part of the lens 15 may be inserted into the tube of the reflector 20. The lens 15 may be made of glass, but in this embodiment, it is made of a colorless, transparent resin. An example of a suitable resin for the lens 15 is silicone resin. The lens 15 has, for example, at least one of dimple-shaped irregularities and surface irregularities due to a textured finish.

[0035] As described above, the outer surface of the reflector 20 has a first flange 23 and a second flange 24 formed thereon, which are used for fixing it to the housing 40. On the other hand, the inner surface 20A of the reflector 20 does not have any structure used for fixing it to the housing 40 or the like. Furthermore, the inner surface 20A is formed in a polyhedral shape, at least along the circumferential direction. By forming the inner surface 20A in a polyhedral shape along the circumferential direction, dust adhering to the inner surface 20A is made less noticeable, and by adding fine diffuse reflection in the circumferential direction, light unevenness can be effectively reduced. As a result, the desired light distribution with less light unevenness can be highly achieved while suppressing unintended diffuse reflection.

[0036] The reflector 20 has an inner diameter that expands from the light inlet 21 to the light outlet 22, with the inner diameter being largest at the light outlet 22. A portion of the reflector 20 is inserted into the cylinder of the cone 30 so that the light outlet 22 is located inside the cylinder of the cone 30. It is conceivable to make the inner diameter of the reflector largest in the axial middle and then decrease towards the light outlet, but this is undesirable because light will hit the inner surface of the cone, increasing the brightness of the cone. In other words, the inner diameter of the reflector 20 must gradually increase from the light inlet 21 to the light outlet 22, with the inner diameter being smallest at the light inlet 21 and largest at the light outlet 22. In this case, the light emitted from the light outlet 22 does not substantially hit the inner surface 30A of the cone 30, and excellent glare-free performance can be achieved.

[0037] The reflector 20, along with the housing 40 covering its outer surface, is inserted into the cylinder of the cone 30 through the first opening 31 of the cone 30. Although the lower end of the reflector 20 is widened, the outer diameter of the lower end of the housing 40 is narrowed, allowing the lower ends of both the reflector 20 and the housing 40 to be inserted into the first opening 31 of the cone 30 without interfering with the cone 30. As a result, the light emission opening 22 of the reflector 20 is closer to the second opening 32 of the cone 30, more effectively suppressing light irradiation to the inner surface 30A of the cone 30. Furthermore, it prevents the unsightly appearance of the ceiling space being visible through the gap between the reflector 20 and the cone 30. As will be described in more detail later, the axial length and aperture diameter of the reflector 20 are important factors in achieving excellent glare-free performance.

[0038] The cone 30 has an inner diameter that widens from the first aperture 31 to the second aperture 32, with the inner diameter being maximum at the second aperture 32. The inner circumferential surface 30A of the cone 30 is formed flat in an axial cross-sectional view taken by a plane containing the optical axis α, and the inclination angle with respect to the axial direction is constant along the axial direction.

[0039] As described above, the lighting device 1 has a frame 60 with a flange 62 positioned below the ceiling panel 100 to cover the periphery of the mounting hole 101, and most of the device, excluding the cone 30 and a portion of the frame 60, is inserted into the mounting hole 101 and positioned in the ceiling space above the ceiling panel 100. Screws 66 for fixing the mounting spring 65 are attached to the cylindrical wall 61 of the frame 60, and these screws 66 fix the frame 60 to the connecting member 70. The lighting device 1 is fixed to the ceiling by the mounting spring 65 (not shown in Figure 4) contacting the ceiling panel 100 in the ceiling space.

[0040] The structure of the reflector 20 and cone 30 will be explained in more detail below, referring to the cross-sectional view in Figure 5. In Figure 5, only the light source 10, lens 15, reflector 20, and cone 30 are shown.

[0041] As shown in Figure 5, the axial length L of the reflecting mirror 20 20 The axial length L of the cone 30 is 30 A longer length is preferable, specifically, an axial length L 30 A value of 140% to 300% is more preferable, and 210% to 240% is particularly preferable. In this case, while suppressing the enlargement of the lighting device 1, it becomes easier to allow the control light emitted from the light output port 22 of the reflector 20 to pass through the cylinder of the cone 30 without hitting the cone 30, thereby improving glare-free performance. The axial length L of the reflector 20 20 One example is a size between 40mm and 50mm.

[0042] Axial length L of the reflecting mirror 20 20 The diameter D of the light emission port 22 is 22 A longer length is preferable, specifically, diameter D 22More preferably, it is 150% or more, and even more preferably 170% or more. The diameter D 22 The axial length L with respect to 20 The ratio (L 20 / D 22 ) has an upper limit of, for example, 250% (L 20 / D 22 = 2.5), and preferably 200%. If the ratio (L 20 / D 22 ) is within this range, while suppressing the increase in size of the lighting device 1, the effect of improving the glare-free performance becomes more significant.

[0043] The diameter D of the light exit port 22 of the reflector 20 22 is smaller than the diameter D of the second opening 32 of the cone 30, and preferably 20% or more and 50% or less of the diameter D 32 , and even more preferably 25% or more and 45% or less. In this case, for example, the light distribution angle of the lighting device 1 can be increased to some extent, and the glare-free performance is also improved. The diameter D 32 If the ratio (D 32 with respect to the diameter D 22 / D 22 / D 32 ) becomes too large, the inner peripheral surface 30A of the cone 30 becomes small, and the inner peripheral surface 20A of the reflector 20 visible from below becomes relatively large. Therefore, for example, when looking up at the lighting device 1, the elevation angle at which the inner peripheral surface 20A of the reflector 20 can be seen becomes small. An example of the diameter D of the light exit port 22 22 is 15 mm or more and 30 mm or less.

[0044] The diameter D of the light incident port 21 of the reflector 20 21 is smaller than the diameter D of the light exit port 22, and preferably 10% or more and 75% or less of the diameter D 22 , and even more preferably 25% or more and 50% or less. In the present embodiment, by changing the ratio (D 22 with respect to the diameter D 22 / D 21 / D 21 / D 22 ), the light distribution angle of the lighting device 1 can be controlled. The ratio (D 21 / D 22 ) is one of the control factors for the light distribution angle, but the ratio (D 21 / D 22The larger the ratio (D), the smaller the beam angle becomes, and the ratio (D 21 / D 22 The smaller the ratio (D), the larger the beam angle. 21 / D 22 If the ratio exceeds 75%, for example, the beam angle may become too large, making it difficult to reduce glare.

[0045] The inner circumferential surface 20A of the reflecting mirror 20 has at least a plurality of mirror surfaces 25 in the circumferential direction and is formed in a polyhedral manner. That is, the inner circumferential surface 20A can be said to be composed of a plurality of mirror surfaces 25 arranged in the circumferential direction. The plurality of mirror surfaces 25 may be formed flat or gently curved in a radial cross-sectional view of the reflecting mirror 20. The recess 26 is the boundary of the plurality of mirror surfaces 25, recessed radially outward from the mirror surfaces 25 of the reflecting mirror 20, and is formed in a thin linear shape along the entire axial length of the reflecting mirror 20. The length (width) of each mirror surface 25 along the circumferential direction of the reflecting mirror 20 is, for example, substantially constant.

[0046] The spacing between the recesses 26 along the circumferential direction of the reflecting mirror 20 is, for example, 1 mm to 5 mm. By forming the inner circumferential surface 20A of the reflecting mirror 20 in a multifaceted manner, for example, dust adhering to the inner circumferential surface 20A becomes less noticeable, and by adding fine diffuse reflection in the circumferential direction, light unevenness can be effectively reduced. In addition, multiple mirror surfaces aligned in the axial direction of the reflecting mirror 20 may be formed on the inner circumferential surface 20A.

[0047] The inner circumferential surface 20A of the reflecting mirror 20 is formed flat from the light inlet 21 to the light outlet 22 in an axial cross-sectional view of the reflecting mirror 20 cut by a plane containing the optical axis α (the central axis of the reflecting mirror 20) (hereinafter simply referred to as "axial cross-sectional view"). That is, the inner circumferential surface 20A illustrated in Figure 5 does not have a curved surface in an axial cross-sectional view, and is formed in a straight line from the light inlet 21 to the light outlet 22.

[0048] Figure 6 is a bottom view of the reflecting mirror 20. As shown in Figure 6, each mirror surface 25 constituting the inner circumferential surface 20A of the reflecting mirror 20 is formed along the entire axial length of the reflecting mirror 20 and gradually widens from the light inlet 21 to the light outlet 22. The mirror surfaces 25 may be flat in a radial cross-sectional view of the reflecting mirror 20, but it is preferable that they are curved so as to be convex radially inward of the reflecting mirror 20. The height of each mirror surface 25 is substantially the same, and a regular pattern of irregularities is formed on the inner circumferential surface 20A of the reflecting mirror 20 by the mirror surfaces 25 and recesses 26 along the circumferential direction. In this case, the effect of reducing the light unevenness becomes more pronounced.

[0049] Figure 7 shows a modified example of the reflector 20, and is an axial cross-sectional view of the reflector cut by a plane containing the optical axis. As illustrated in Figure 7, the inner surface of the reflector may be curved in an axial cross-sectional view. The inner surface 20Ax of the reflector 20x shown in Figure 7(a) is gently curved from the light entrance 21x to the light exit 22x so as to be convex radially outward of the reflector 20x. Similarly, the inner surface 20Ay of the reflector 20y shown in Figure 7(b) is curved so as to be convex radially outward of the reflector 20y, just like the reflector 20x, but the degree of curvature is greater than that of the reflector 20x, and the difference in diameter between the light entrance 21y and the light exit 22y is larger. When the reflector 20y is used, the light distribution angle of the lighting device can be narrowed compared to when the reflector 20x is used. Furthermore, the inner surface 20Az of the reflecting mirror 20z shown in Figure 7(c) is curved so as to be convex radially outward on the light entrance 21z side, and slightly curved so as to be convex radially inward on the light exit 22z side.

[0050] As shown in Figure 5, the inner circumferential surface 30A of the cone 30 is formed flat and inclined at a predetermined angle with respect to the optical axis α (central axis of the cone 30) in an axial cross-sectional view of the cone 30 cut by a plane containing the optical axis α (central axis of the cone 30). The inner circumferential surface 30A may be gently curved, for example, convex radially outward or radially inward of the cone 30. Here, the inclination angle of the inner circumferential surface 30A with respect to the optical axis α is preferably 40° to 60°, and particularly preferably around 45°. In this case, the improvement effect of glare-free performance becomes more pronounced while suppressing the increase in size of the lighting device 1.

[0051] As described above, the reflector 20 and the cone 30 are configured such that the light emitted from the light output opening 22 of the reflector 20 substantially does not hit the cone 30. Figure 5 illustrates the light rays L1 to L4 emitted from the light-emitting unit 12, but none of the light hits the inner surface 30A of the cone 30 and is emitted from the second aperture 32. Unless the specularity of the reflector 20 is 100%, even a reflector made of a rotating body with a perfectly circular cross-section will generate unintended diffuse reflection components, but in the lighting device 1, light other than the diffuse reflection components does not hit the inner surface 30A of the cone 30. The diffuse reflection components illuminate the inner surface 30A of the cone 30 softly, to the extent that it is not dazzling.

[0052] The inner surface 30A of the cone 30 does not function as a reflective surface and therefore does not need to be mirror-finished, but it may be mirror-finished or a diffuse reflective surface. Furthermore, the inner surface 30A of the cone 30 may have a baffle shape or a matte finish. Since the inner surface 30A does not substantially affect the light distribution of the lighting device 1, it can be freely designed to match the ceiling design. The cone 30 may have multiple design variations and be interchangeable to match the ceiling design.

[0053] As described above, the lighting device 1 with the above configuration can achieve excellent glare-free performance. The lighting device 1 is suitable for downlights and can significantly reduce glare compared to conventional glare-free downlights.

[0054] Since the lighting device 1 is configured so that no light other than the diffuse reflection component strikes the inner surface 30A of the cone 30, glare caused by diffuse reflection when light strikes the cone is not a problem. For this reason, there are no light distribution constraints on the design of the inner surface 30A of the cone 30 that is visible to the user, and for example, a design that blends in with the ceiling can be applied. When looking up from below, the lighting device 1 does not cause glare as long as the angle is such that the inner surface 20A of the reflector 20 is not visible.

[0055] Also, the diameter D of the light emission opening 22 of the reflector 2022 The axial length L of the reflecting mirror 20 20 Ratio (L 20 / D 22 ), Diameter D of the light emission port 22 22 Diameter D of the light entry port 21 relative to 21 The ratio (D 21 / D 22 ), diameter D of the second opening 32 of the cone 30 32 Diameter D of the light entry port 21 relative to 21 The ratio (D 22 / D 32 If the above conditions are met, the improvement in glare-free performance will be even more pronounced.

[0056] The above embodiments can be modified as appropriate without impairing the purpose of this disclosure. For example, in the above embodiments, a substantially cylindrical reflector 20 that gradually widens in diameter from the light inlet 21 to the light outlet was exemplified as the light control member, but it is also possible to use a lens that can control the light distribution in the same way as a reflector.

[0057] Furthermore, the light control member can also be a long reflector. Another example of the embodiment is a lighting device comprising a long light source module, a long reflector, and a long cone. The long reflector widens from the light inlet to the light outlet so as to maximize the distance between the opposing inner surfaces at the light outlet, and a part of the light control member is inserted into the cone so that the light outlet is located inside the cone. The long lighting device has a widthwise cross-sectional shape similar to the cross-sectional shape shown in Figure 5, for example. The reflector and cone are configured so that substantially all of the light emitted from the light outlet of the reflector passes through the inside of the cone without hitting it. In this case, the same glare-free performance as lighting device 1 can be obtained in the widthwise direction of the long lighting device.

[0058] Figure 8 shows a modified example of the cone 30. As shown in Figure 8, the inner circumferential surface 30A of the cone 30 may be curved so as to gradually follow the axial direction toward the first opening 31. The upper end of the cone 30 is gently curved so as to be convex radially inward, and the inclination angle of the inner circumferential surface 30A with respect to the axial direction changes significantly above and below this curved portion. That is, within a predetermined length range from the first opening 31 of the cone 30, a portion is formed in which the inner circumferential surface 30A is substantially aligned with the axial direction of the cone 30. In this case, the unsightly appearance caused by the ceiling space being visible through the gap between the reflector 20 and the cone 30 can be more effectively suppressed.

[0059] In the example shown in Figure 8, the reflector 20 is inserted together with the housing 40 into the cylinder of the cone 30 from the first opening 31 for a length L. In other words, the reflector 20 and the cone 30 overlap by a length L in the axial direction. The length L is, for example, 2.0 mm or more. If the length L is too long, the reflector 20 will be conspicuous, and the aesthetic appeal of the lighting device 1 may be reduced. Also, the angle at which the inner surface 20A of the reflector 20 is visible when looking up at the lighting device 1 (elevation angle) will be small. The upper limit of the length L is, for example, 5.0 mm.

[0060] Figure 9 is a perspective view of lighting device 2, which is another example of the embodiment. In Figure 9, the same reference numerals are used for components that are the same as in the above embodiment. As shown in Figure 9, lighting device 2 differs from lighting device 1 in that it has a heat dissipation member 55 in which a plurality of heat dissipation fins 57 protrude significantly from directly above the housing 40. The plurality of heat dissipation fins 57 are erected on a base 56 fixed to the housing 40 and formed in a plate shape, but they bend at approximately a right angle midway and extend in a direction perpendicular to the axial direction of the housing 40. Furthermore, lighting device 2 differs from lighting device 1, which has four mounting springs 65, in that it has three mounting springs 65.

[0061] This disclosure is further illustrated by the following embodiments. Configuration 1: A lighting device comprising a light source, a light control member for controlling the light emitted from the light source, and a cone provided on the opposite side of the light source from the light control member, the cone expanding as it moves away from the light control member, wherein the light control member has a light inlet on the light source side and a light outlet on the cone side, and expands from the light inlet towards the light outlet so as to maximize the distance between the opposing inner surfaces at the light outlet, and the light control member and the cone are configured such that the light emitted from the light outlet passes through the inside of the cone without substantially hitting the cone. Configuration 2: A lighting device comprising a light source, a cylindrical light control member for controlling the light emitted from the light source, and a cylindrical cone provided on the side opposite to the light source in the axial direction of the light control member, and which expands in diameter as it moves away from the light control member, wherein the light control member has a light inlet on the light source side and a light outlet on the cone side, and expands in diameter from the light inlet to the light outlet so that the inner diameter is maximized at the light outlet, and the light control member and the cone are configured such that the light emitted from the light outlet passes through the cylinder of the cone without substantially hitting the cone. Configuration 3: In the lighting device described in Configuration 2, the inner circumferential surface of the light control member is formed in a polyhedral manner, having at least a plurality of mirror surfaces in the circumferential direction. Configuration 4: In the lighting device described in Configuration 3, the plurality of mirror surfaces are curved so as to be convex radially inward of the light control member. Configuration 5: In the lighting device described in any one of Configurations 2 to 4, the light control member has an axial length of 150% or more of the diameter of the light output opening. Configuration 6: In the lighting device described in any one of Configurations 2 to 5, the cone has a first opening on the side of the light control member and a second opening on the opposite side of the first opening, and the diameter of the light output opening of the light control member is 20% or more and 50% or less of the diameter of the second opening of the cone. Configuration 7: In the lighting device described in any one of Configurations 2 to 6, the diameter of the light inlet of the light control member is 10% or more and 75% or less of the diameter of the light outlet. Configuration 8: In the lighting device described in any one of Configurations 2 to 7, the axial length of the light control member is 140% or more and 300% or less of the axial length of the cone. Configuration 9: The lighting device according to any one of Configurations 2 to 8, further comprising a lens disposed between the light source and the light control member. Configuration 10: In the lighting device described in any one of Configurations 2 to 9, the inner circumferential surface of the cone has an inclination angle of 45° or more with respect to the optical axis in an axial cross-sectional view of the cone cut by a plane containing the optical axis. Configuration 11: In the lighting device described in any one of Configurations 2 to 10, a part of the light control member is inserted into the cone such that the light output port is located inside the cone. Configuration 12: A lighting device described in any one of Configurations 1 to 11, wherein the lighting device is a ceiling-mounted device. [Explanation of Symbols]

[0062] 1. Lighting device 10 light source 11 circuit boards 12 Light-emitting part 15 lenses 16 holders 17 Fixing member 20 Reflector 20A inner surface 21 Light entrance 22 Light Emission Port 23 First Flange 24. Second flange 25 Mirror surface 26 recesses 30 cones 30A inner surface 31. First opening 32. Second opening 33 Locking part 40 cabinets 41 Large diameter section 42 Small diameter section 43 Flange 44 Convex part 45 Retaining ring 46 Step part 50 Heat dissipation components 51 Base 52 heat dissipation fins 60 slots 61 Cylinder wall 62 Flange 65 Mounting spring 66 screws 70 Connecting member 71 1st connection part 72 2nd connection part 100 Ceiling boards 101 Embedded hole

Claims

1. Light source and A light control member that controls the light emitted from the light source, A cone is provided on the opposite side of the light source, with the light control member in between, and which widens as it moves away from the light control member, A lighting device comprising, The light control member has a light inlet on the light source side and a light outlet on the cone side, and expands from the light inlet towards the light outlet so that the distance between the opposing inner surfaces at the light outlet is maximized. A lighting device in which the light control member and the cone are configured such that light emitted from the light outlet passes through the inside of the cone without substantially hitting the cone.

2. In the lighting device according to claim 1, The light control member and the cone are formed in a cylindrical shape. The light control member expands in diameter from the light inlet to the light outlet so that its inner diameter is maximized at the light outlet. The cone is provided on the side opposite to the light source in the axial direction of the light control member, and its diameter increases as it moves away from the light control member.

3. In the lighting device according to claim 2, The inner circumferential surface of the light control member is formed in a polyhedral manner, having at least a plurality of mirror surfaces in the circumferential direction.

4. In the lighting device according to claim 3, The plurality of mirror surfaces are curved so as to be convex radially inward of the light control member.

5. In the lighting device according to any one of claims 2 to 4, The light control member has an axial length of 150% or more of the diameter of the light emission port.

6. In the lighting device according to any one of claims 2 to 4, The cone has a first opening on the side of the light control member and a second opening on the opposite side of the first opening. The diameter of the light emission port of the light control member is 20% or more and 50% or less of the diameter of the second opening of the cone.

7. In the lighting device according to any one of claims 2 to 4, The diameter of the light inlet of the light control member is 10% or more and 75% or less of the diameter of the light outlet.

8. In the lighting device according to any one of claims 2 to 4, The axial length of the light control member is 140% or more and 300% or less of the axial length of the cone.

9. In the lighting device according to any one of claims 2 to 4, The system further includes a lens positioned between the light source and the light control member.

10. In the lighting device according to any one of claims 2 to 4, The inner circumferential surface of the cone has an inclination angle of 45° or more with respect to the optical axis when viewed in an axial cross-section of the cone cut by a plane containing the optical axis.

11. In the lighting device according to any one of claims 2 to 4, The light control member is partially inserted into the cone such that the light emission port is located inside the cone.

12. A lighting device according to any one of claims 2 to 4, The aforementioned lighting device is a ceiling-mounted type.

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