Lighting fixtures

Abstract

This disclosure aims to reduce brightness unevenness. [Solution] The lighting fixture 100 comprises a light source 32, a scattering lens 4, a reflector 5, and an angle changing mechanism. The scattering lens 4 has multiple scattering parts for scattering light. The reflector 5 has a reflective surface 50 that reflects the light emitted from the scattering lens 4. The angle changing mechanism changes the angle between the reflector 5 and the scattering lens 4. In the lighting fixture 100, when the average Gaussian scattering angle of the reflective surface 50 of the reflector 5 is σ1 [degree] and the average distance between adjacent scattering parts among the multiple scattering parts is L0 [mm], the ratio of the average distance to the average Gaussian scattering angle M = L0 / σ1 satisfies the relationship M < 3.

Description

[Technical Field]

[0001] This disclosure generally relates to lighting fixtures. More specifically, this disclosure relates to lighting fixtures comprising lenses and reflectors. [Background technology]

[0002] Patent Document 1 describes an LED lighting fixture aimed at suppressing unevenness in the emitted light.

[0003] The LED lighting fixture described in Patent Document 1 comprises an LED light source unit having LEDs and a reflective member. The reflective member has an incident aperture into which light from the LED light source unit enters, an exit aperture from which the light incident from the incident aperture exits, and a reflective surface that connects the incident aperture and the exit aperture and reflects light. The incident aperture plane, which is the plane containing the incident aperture, is inclined with respect to the exit aperture plane, which is the plane containing the exit aperture. The reflective surface has a first line segment and a second line segment, which are lines of intersection with a reference plane. The reference plane is a plane that is perpendicular to the incident aperture plane and the exit aperture plane and passes through the center of the incident aperture plane and the center of the exit aperture plane. The first line segment is longer than the second line segment. The second angle, which is the angle that the second line segment makes with the exit aperture plane, is greater than the first angle, which is the angle that the first line segment makes with the exit aperture plane. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2019-212546 [Overview of the project] [Problems that the invention aims to solve]

[0005] In the field of lighting fixtures, there is a demand for reducing brightness unevenness (unevenness of illuminated light).

[0006] This disclosure aims to reduce brightness unevenness. [Means for solving the problem]

[0007] A lighting fixture according to one aspect of the present disclosure comprises a light source, a scattering lens, a reflector, and an angle changing mechanism. The scattering lens has a plurality of scattering parts for scattering light. The reflector has a reflective surface that reflects light emitted from the scattering lens. The angle changing mechanism changes the angle between the reflector and the scattering lens. In the lighting fixture, when the average Gaussian scattering angle of the reflective surface of the reflector is σ1 [degree] and the average distance between adjacent scattering parts among the plurality of scattering parts is L0 [mm], the ratio of the average distance to the average Gaussian scattering angle M = L0 / σ1 satisfies the relationship M < 3. [Effects of the Invention]

[0008] This disclosure has the advantage of making it possible to reduce brightness unevenness. [Brief explanation of the drawing]

[0009] [Figure 1] Figure 1 is a perspective view of a lighting fixture according to one embodiment. [Figure 2] Figure 2 is a cross-sectional view of the same lighting fixture. [Figure 3] Figure 3 is an exploded perspective view of the same lighting fixture. [Figure 4] Figure 4 is an exploded perspective view of the light fixture unit of the same lighting fixture. [Figure 5] Figure 5 is a perspective view of the scattering lens provided in the light fixture shown above. [Figure 6] Figure 6 is a cross-sectional view of the vicinity of the emission surface of the scattering lens shown above. [Figure 7] Figure 7 is an exploded perspective view of the base of the same lighting fixture. [Figure 8] Figure 8 is an explanatory diagram illustrating the reflection of light from the reflective surface of the reflector provided in the base portion shown above. [Figure 9] Figure 9 is a side view showing the first state of the lighting fixture described above. [Figure 10]FIG. 10 is a side view showing the second state of the lighting fixture described above. [Figure 11] FIG. 11 is an enlarged view of the vicinity of the light-emitting surface of the scattering lens of Modification 1. [Figure 12] FIG. 12 is an enlarged view of the vicinity of the light-emitting surface of the scattering lens of Modification 2. [Figure 13] FIG. 13 is a cross-sectional view of the vicinity of the light-emitting surface of the scattering lens of Modification 3. [Figure 14] FIG. 14 is a cross-sectional view of the reflector of Modification 4. [Figure 15] FIG. 15 is a cross-sectional view of the reflector of Modification 5. [Figure 16] FIG. 16 is an image showing the intensity distribution of the light reflected by the reflector of the lighting fixture of Reference Example 1. [Figure 17] FIG. 17 is an image showing the intensity distribution of the light reflected by the reflector of the lighting fixture of Reference Example 2. [Figure 18] FIG. 18 is an explanatory diagram for explaining the angular dependence of luminance unevenness. [Figure 19] FIG. 19 is an explanatory diagram for explaining the determination criteria for the presence or absence of luminance unevenness. [Figure 20] FIG. 20 is an explanatory diagram for explaining the determination criteria for the presence or absence of luminance unevenness.

MODE FOR CARRYING OUT THE INVENTION

[0010] (1) Embodiment Hereinafter, the lighting fixture according to the embodiment will be described with reference to the drawings. However, the following embodiment is only one of various embodiments of the present disclosure. The following embodiment can be variously modified according to design and the like as long as the object of the present disclosure can be achieved. Also, each drawing described in the following embodiment is a schematic drawing, and the ratio s of the size and thickness of each component in the drawing does not necessarily reflect the actual dimensional ratio.

[0011] The lighting fixture 100 is a downlight, which is mounted on the ceiling, for example, so as to be exposed through a hole in the ceiling of a room in a facility. The lighting fixture 100 of this embodiment is a so-called universal downlight, in which the direction of light irradiation can be changed within a predetermined angular range. The lighting fixture 100 is used, for example, to illuminate a portion of a room that spans from the wall to the floor. The lighting fixture 100 can be mounted, for example, at a height of 2.4 to 3.0 m from the floor and at a position of 0.15 to 1.0 m from the wall.

[0012] As shown in Figures 1 to 3, the lighting fixture 100 comprises a lamp body 10 and a base 20. The base 20 is positioned above the ceiling and fixed to the ceiling. The lamp body 10 is connected to the base 20 so as to be tiltable within a predetermined angular range relative to the base 20.

[0013] In the following explanation, for the sake of clarity, the vertically upward direction (towards the ceiling) and the vertically downward direction (towards the floor) will be referred to as "up" when the lighting fixture 100 is installed on the ceiling. However, the orientation provisions in this disclosure merely indicate the relative positional relationship between the components of the lighting fixture 100 and do not limit the orientation of the lighting fixture 100 when it is in use.

[0014] (1.1) Light body part As shown in Figure 4, the light fixture 10 comprises a first main body 1, a light source unit 3, a scattering lens 4, and a heat dissipation unit 6.

[0015] (1.1.1) Light source unit As shown in Figure 4, the light source unit 3 comprises a rectangular plate-shaped substrate 31 and a light source 32. The light source unit 3 is, for example, a COB (Chip on Board) type light source, but is not limited to this and may be an SMD (Surface Mound Device) type light source.

[0016] The light source 32 is mounted on the underside of the substrate 31. The light source 32 has at least one LED (Light Emitting Diode). If the light source 32 has multiple LEDs, the connections between the multiple LEDs may be in series or parallel, or both. In the light source unit 3, power is supplied to the substrate 31 from an external power source, and the supplied power lights up the light source 32, causing the light source 32 to emit light.

[0017] (1.1.2) Scattering lenses The scattering lens 4 is a transparent optical component for controlling the light distribution from the light source unit 3. The scattering lens 4 is composed of a single component.

[0018] As shown in Figures 2 and 4, the scattering lens 4 integrally comprises a convex lens-shaped lens body 41, a cylindrical portion 42 provided around the lens body 41, a light-diffusing portion 43, and a flange portion 44.

[0019] The cylindrical portion 42 is tapered and has an inner surface that rises upward from the periphery of the lens body 41, and an outer surface whose diameter gradually increases from the upper end to the lower end of the inner surface.

[0020] The light-diffusing section 43 is disc-shaped and is located at the lower end of the scattering lens 4.

[0021] The flange portion 44 is provided along the outer circumference of the light-diffusing portion 43. The thickness of the flange portion 44 is the same as the thickness of the light-diffusing portion 43, but it is not limited to this and may be different.

[0022] In the scattering lens 4, the upper surface (convex curved surface) of the lens body 41 and the inner surface of the cylindrical portion 42 constitute the incident surface 401 into which light from the light source unit 3 enters. In addition, the lower surface of the light diffusion portion 43 constitutes the exit surface 402 into which the light that entered the incident surface 401 is emitted.

[0023] As shown in FIGS. 5 and 6, a plurality of scattering portions 49 are provided on the exit surface 402 (the lower surface of the light diffusion portion 43) of the scattering lens 4. FIG. 5 also shows an enlarged view of a partial region of the exit surface 402 as viewed along the normal direction of the exit surface 402.

[0024] As shown in FIG. 6, the scattering portion 49 is, here, a recess 491 recessed upward. The recess 491 is, for example, a concave lens (microlens) formed of a part of a spherical surface with a radius of r. As shown in FIG. 5, a plurality of recesses 491 are provided on the exit surface 402 without gaps.

[0025] As shown in the enlarged view of FIG. 5, the outer shape of the recess 491 as viewed along the normal direction of the exit surface 402 is a regular hexagon. That is, a plurality of recesses 491 each formed of a part of a spherical surface are provided on the exit surface 402 without gaps (densely), so that the boundaries between adjacent recesses 491 are linear when viewed along the normal direction of the exit surface 402, and the outer shape of the recess 491 becomes a regular hexagon. Thereby, the plurality of recesses 491 are arranged in a honeycomb shape on the exit surface 402. The enlarged view of FIG. 5 also shows the circumcircle of the regular hexagon-shaped recess 491 by a dashed line. Although not particularly limited, the diameter R0 of the circumcircle of the recess 491 is, for example, about 0.025 mm to 4 mm.

[0026] In the scattering lens 4 of the present embodiment, the distance L1 between two adjacent scattering portions 49 is the distance between the centers of the circumcircles of the recesses 491 that are the two scattering portions 49, and is expressed by the formula L1 = (√3) / 2 × R0 using the diameter R0 of the circumcircle of the recess 491. Therefore, the average distance L0 between adjacent scattering portions 49 among the plurality of scattering portions 49 is expressed as L0 = L1 = (√3) / 2 × R0. Thus, in the scattering lens 4 of the present embodiment, the average distance L0 between adjacent scattering portions 49 among the plurality of scattering portions 49 and the diameter R0 of the circumcircle of the recess 491 satisfy the relationship L0 < R0.

[0027] In the lighting fixture 100 of this embodiment, multiple scattering parts 49 are provided on the emission surface 402 of the scattering lens 4, so that the light emitted from the scattering lens 4 is scattered light rather than parallel light. This can reduce brightness unevenness.

[0028] (1.1.3) Heat dissipation unit The heat dissipation unit 6 is provided to release the heat from the light source unit 3 into the surrounding environment.

[0029] The heat dissipation unit 6 is made of a metal such as aluminum. As shown in Figures 2 and 4, the heat dissipation unit 6 has a cylindrical portion 61 and a fin portion 62.

[0030] The cylindrical portion 61 is a substantially cylindrical shape with a bottom. The cylindrical portion 61 has a bottom wall on its upper side. On the side wall of the cylindrical portion 61, a pair of flat plate portions 611 extending in the axial direction of the cylindrical portion 61 are provided at 180-degree intervals.

[0031] The fin section 62 has a plurality of plate-shaped heat dissipation fins 621. The heat dissipation fins 621 are plate-shaped and extend upward from the upper surface of the cylindrical section 61. The plurality of heat dissipation fins 621 are arranged radially. The heat dissipation unit 6 can have improved heat dissipation performance by being equipped with heat dissipation fins 621.

[0032] (1.1.4) First main body The first main body portion 1 is formed of a resin such as polybutylene terephthalate (PBT). However, it is not limited to this, and part or all of the first main body portion 1 may be formed of metal or the like.

[0033] As shown in Figure 4, the first main body 1 comprises a first cylindrical body 11 and a first connecting body 12.

[0034] The first cylindrical body 11 integrally comprises a cylindrical portion 111 and an auxiliary wall portion 112.

[0035] As shown in Figure 2, the cylindrical portion 111 has, in order from top to bottom, a first frustoconical portion which is hollow and has a diameter that increases towards the bottom, an annular portion which extends outward from the lower end of the first frustoconical portion, a second frustoconical portion which is hollow and has a diameter that increases towards the bottom and is connected to the outer end of the annular portion, and a cylindrical portion which extends downward from the lower end of the second frustoconical portion.

[0036] A scattering lens 4 is positioned within the space enclosed by the cylindrical portion 111. The cylindrical portion 111 also supports the light source unit 3 such that the light source 32 of the light source unit 3 is exposed from the upper opening of the first frustum of the cone. As a result, light from the light source 32 is emitted into the space enclosed by the cylindrical portion 111 and incident on the incident surface 401 of the scattering lens 4. Some of the light emitted into the cylindrical portion 111 may be scattered by the inner surface of the cylindrical portion 111 (such as the inner surface of the first frustum of the cone) and incident on the scattering lens 4. The light source unit 3 may also be mounted on the lower surface of the bottom wall of the cylindrical portion 61 of the heat dissipation unit 6.

[0037] The auxiliary wall portion 112 is provided on the upper side of the cylindrical portion 111. Connectors for external connections and the like are arranged on the auxiliary wall portion 112.

[0038] The first connecting body 12 is cylindrical. As shown in Figures 2 and 4, the first connecting body 12 has an upper cylindrical portion 121, a lower cylindrical portion 122 that is continuous below the upper cylindrical portion 121, and a connecting portion 123.

[0039] The upper cylindrical portion 121 is substantially cylindrical with open bottom surfaces on both sides. A pair of flat plate portions 124 extending in the axial direction of the upper cylindrical portion 121 are provided on the side walls of the upper cylindrical portion 121 at 180-degree intervals.

[0040] The lower cylindrical portion 122 is roughly cylindrical with both bottom surfaces open. The diameter of the lower cylindrical portion 122 is smaller than the diameter of the upper cylindrical portion 121.

[0041] The side wall of the lower cylindrical portion 122 is provided with a pair of flat plate portions 125 extending in the axial direction of the lower cylindrical portion 122, spaced 180 degrees apart. The outer surface of the flat plate portions 125 of the lower cylindrical portion 122 is connected to the outer surface of the flat plate portion 124 of the upper cylindrical portion 121.

[0042] The lower end of the flat plate portion 125 in the lower cylindrical portion 122 is inclined such that the length of the flat plate portion 125 gradually increases from one end to the other, in a direction perpendicular to both the thickness direction of the flat plate portion 125 and the axial direction of the lower cylindrical portion 122. Furthermore, a through hole 126 is formed in the flat plate portion 125 of the lower cylindrical portion 122.

[0043] The connecting portion 123 is a flat plate with a circular opening 127 (see Figure 2) in the center. The connecting portion 123 connects the lower end of the upper cylindrical portion 121 and the upper end of the lower cylindrical portion 122.

[0044] The first cylindrical body 11 and the first connecting body 12 are fixed to the heat dissipation unit 6 using screws or the like, with the flange portion 44 of the scattering lens 4 sandwiched between the upper surface of the periphery of the opening 127 in the first connecting body 12 and the lower end of the cylindrical portion 111 of the first cylindrical body 11 (see Figure 2). In this way, the first cylindrical body 11, the first connecting body 12, the scattering lens 4, and the heat dissipation unit 6 constitute an integrated lamp body 10.

[0045] (1.2) Base As shown in Figure 7, the base portion 20 comprises a second main body portion 2 and a reflector 5.

[0046] (1.2.1) Reflector As shown in Figure 2, the reflector 5 is positioned below the scattering lens 4. The reflector 5 reflects the light emitted from the scattering lens 4 downwards.

[0047] As shown in Figures 2 and 7, the reflector 5 is cylindrical with an outer surface 51 and an inner surface 52. The cross-section of the reflector 5 when cut horizontally is circular. The diameter of the reflector 5 gradually increases towards the bottom. The reflector 5 has a flange 54 at its lower end.

[0048] The reflector 5 has an internal space 500 (see Figure 2) with a circular cross-section. The internal space 500 is surrounded on the sides by an inner surface 52. The reflector 5 has an entrance opening 501 formed on its upper surface and an exit opening 502 formed on its lower surface. Light from the scattering lens 4 enters the internal space 500 through the entrance opening 501 and is emitted from the exit opening 502.

[0049] In this embodiment, the opening surface of the outlet port 502 is parallel to a plane perpendicular to the vertical direction (horizontal plane). On the other hand, the opening surface of the inlet port 501 is inclined with respect to the horizontal plane. That is, the opening surface of the inlet port 501 is inclined with respect to the opening surface of the outlet port 502. As shown in Figure 2, the imaginary line X20 connecting the center P1 of the inlet port 501 and the center P2 of the outlet port 502 is inclined with respect to the central axis X10 of the cylindrical reflector 5 (an axis passing through the center P2 of the outlet port 502 and perpendicular to the opening surface of the outlet port 502).

[0050] The inner surface 52 of the reflector 5 constitutes a reflective surface 50 that reflects light emitted from the scattering lens 4. The reflective surface 50 is made of, for example, a thin aluminum film formed by depositing aluminum.

[0051] The reflective surface 50 reflects (i.e., scatters) the light from the scattering lens 4 with a certain degree of spread. In the following, the degree of spread of the reflected light by the reflective surface 50 (i.e., the degree of light scattering by the reflective surface 50) will be expressed using the mean Gaussian scattering angle σ1 [degree]. The mean Gaussian scattering angle σ1 is the standard deviation of the Gaussian distribution, assuming that the intensity distribution of the reflected light follows a Gaussian distribution. Specifically, the mean Gaussian scattering angle σ1 is defined by the following equation (1).

[0052]

number

[0053] Here, P(θ) is the luminous intensity or radiance in the θ direction of the reflected light, and P0 is the luminous intensity or radiance in the specular direction of the reflected light (see Figure 8).

[0054] In the lighting fixture 100 of this embodiment, the reflective surface 50 of the reflector 5 scatters the light from the scattering lens 4, thereby reducing brightness unevenness.

[0055] (1.2.2) Second main body The second main body portion 2 is formed of a resin such as polybutylene terephthalate (PBT). However, it is not limited to this, and part or all of the second main body portion 2 may be formed of metal or the like.

[0056] As shown in Figure 7, the second main body 2 comprises a second cylindrical body 21, a flange body 22, and a second connecting body 23.

[0057] The second cylindrical body 21 integrally comprises a cylindrical portion 211 and a flange portion 212.

[0058] The cylindrical portion 211 is roughly cylindrical with openings on both sides. Three connecting holes 213 are provided near the upper end of the cylindrical portion 211. The three connecting holes 213 are spaced 120 degrees apart. Two connecting holes 214 are provided on the side wall of the cylindrical portion 211, spaced 180 degrees apart. In addition, mounting holes 216 are provided on the side wall of the cylindrical portion 211 at positions different from the connecting holes 213 and connecting holes 214.

[0059] The flange portion 212 is flange-shaped, extending inward and outward from the upper end of the cylindrical portion 211. Two retaining claws 215 for holding the second connecting body 23 are provided on the upper surface of the flange portion 212, at positions rotated ±120 degrees from the mounting hole 216 with respect to the central axis of the cylindrical portion 211.

[0060] The flange body 22 integrally comprises a cylindrical portion 221 and a flange portion 222.

[0061] The cylindrical portion 221 is roughly cylindrical with openings on both sides. The cylindrical portion 221 has two connecting holes 223 spaced 180 degrees apart. In addition, the cylindrical portion 221 has three notches 224 spaced 120 degrees apart.

[0062] The flange portion 222 is flange-shaped, extending outward from the lower end of the cylindrical portion 221. The flange body 22 has an opening 225 on its lower surface (see Figure 2).

[0063] The second cylindrical body 21 and the flange body 22 are joined together by overlapping the two connecting holes 214 of the second cylindrical body 21 with the two connecting holes 223 of the flange body 22 and fastening them with bolts and nuts. At this time, the flange portion 54 of the reflector 5 is sandwiched between the peripheral edge of the opening 225 of the flange body 22 and the lower end of the second cylindrical body 21 (see Figure 2), and the second cylindrical body 21 and the flange body 22 are joined together.

[0064] The second connecting body 23 is cylindrical. As shown in Figure 7, the second connecting body 23 has an upper cylindrical portion 231, a lower cylindrical portion 232 that is continuous below the upper cylindrical portion 231, and a connecting portion 233.

[0065] The upper cylindrical portion 231 is substantially cylindrical with open bottom surfaces on both sides. A flat plate portion 234 extending in the axial direction of the upper cylindrical portion 231 is provided on the side wall of the upper cylindrical portion 231. In addition, a flat plate portion 235, which is flat and has an arc-shaped upper end, is provided on the side wall of the upper cylindrical portion 231 at a position rotated ±90 degrees from the flat plate portion 234 with respect to the central axis of the upper cylindrical portion 231. A through hole 236 is formed in the flat plate portion 235.

[0066] The lower cylindrical portion 232 is roughly cylindrical with open bottom surfaces on both sides. The diameter of the lower cylindrical portion 232 is larger than the diameter of the upper cylindrical portion 231. A flange is formed at the lower end of the lower cylindrical portion 232.

[0067] The connecting portion 233 connects the lower end of the upper cylindrical portion 231 to the upper end of the lower cylindrical portion 232.

[0068] The second connecting body 23 is connected to the second cylindrical body 21 and the flange body 22. More specifically, with the flange portion at the lower end of the lower cylindrical portion 232 of the second connecting body 23 fitted inside the retaining claws 215 of the second cylindrical body 21, the L-shaped retaining member is screwed into a mounting hole 216 formed in the side wall of the flange body 22, thereby connecting the second connecting body 23 to the second cylindrical body 21 and the flange body 22. As a result, the second cylindrical body 21, the flange body 22, the second connecting body 23, and the reflector 5 constitute an integrated base portion 20.

[0069] As shown in Figure 1, L-shaped mounting springs 24 are attached to the three connecting holes 213 of the second cylindrical body 21. For example, the base portion 20 is fixed to the ceiling by sandwiching a ceiling plate between the flange portion 222 of the flange body 22 and the mounting spring 24. For convenience, the mounting springs 24 are not shown in figures other than Figure 1.

[0070] (1.3) Connection between the light fixture and the base The lamp body 10 is connected to the base 20. Specifically, with the two through holes 126 of the first connecting body 12 in the lamp body 10 and the two through holes 236 of the second connecting body 23 in the base 20 aligned, bolts are passed through the through holes 126 and 236. In this state, nuts are attached to the bolts, thereby fixing the lamp body 10 to the base 20.

[0071] The lamp body 10 is tiltable with respect to the base 20. More specifically, the lamp body 10 is rotatable with respect to the base 20 around a rotation axis passing through four through holes 126, 236. The lamp body 10 is tiltable with respect to the base 20 within a range between a first state (see Figure 9) in which the central axis A1 of the cylindrical lamp body 10 and the central axis A2 of the cylindrical base 20 are parallel, and a second state (see Figure 10) in which the angle (tilt angle) φ between the central axes A1 and A2 is a predetermined angle (for example, 30 degrees).

[0072] If the user wishes to change the inclination angle φ between the light unit 10 and the base unit 20, they can loosen the nuts from the bolts that pass through the through holes 126 and 236, rotate the light unit 10 around the rotation axis by the desired angle relative to the base unit 20, and then tighten the nuts again.

[0073] By changing the inclination angle φ between the light unit 10 and the base unit 20, the angle between the reflector 5 on the base unit 20 and the scattering lens 4 on the light unit 10 is also changed. In other words, the lighting fixture 100 is equipped with an angle changing mechanism (through holes 126, 236) that changes the angle between the reflector 5 and the scattering lens 4.

[0074] (1.4) Modifications of scattering lenses and reflectors The light diffusion portion 43 of the scattering lens 4 is not limited to the structure shown in Figures 4 to 6.

[0075] Figure 11 shows the structure of the light diffusion portion 43 of the scattering lens 4 of Modified Example 1. Figure 11 is an enlarged view of a portion of the emission surface 402 of the scattering lens 4 of Modified Example 1, viewed along the direction normal to the emission surface 402.

[0076] In the scattered lens 4 of Modified Example 1 shown in Figure 11, circular recesses 491, which serve as scattering portions 49, are arranged on the emission surface 402 such that their outer circumferences are in contact with each other. In the scattered lens 4 of Modified Example 1, the distance L1 between two adjacent scattering portions 49 is equal to the diameter R0 of the recess 491 (L1=R0). Therefore, the average distance L0 between adjacent scattering portions 49 among the multiple scattering portions 49 is equal to the diameter R0 of the recess 491 (L0=L1=R0).

[0077] Figure 12 shows the structure of the light diffusion portion 43 of the scattering lens 4 in Modified Example 2. Figure 12 is an enlarged view of a portion of the emission surface 402 of the scattering lens 4 in Modified Example 2, viewed along the direction normal to the emission surface 402.

[0078] In the modified example 2 of the scattering lens 4 shown in Figure 12, circular recesses 491, which serve as scattering portions 49, are arranged on the emission surface 402, spaced apart from each other so that their outer edges do not touch. However, the multiple scattering portions 49 are uniformly arranged on the emission surface 402. In the modified example 2 of the scattering lens 4, the distance L1 between two adjacent scattering portions 49 is greater than the diameter R0 of the recess 491 (L1>R0). Therefore, the average distance L0 between adjacent scattering portions 49 among the multiple scattering portions 49 is greater than the diameter R0 of the recess 491 (L0=L1>R0).

[0079] Figure 13 shows the structure of the light diffusion portion 43 of the scattering lens 4 of Modified Example 3. Figure 13 is a cross-sectional view of the scattering lens 4 of Modified Example 3 along the direction normal to the output surface 402.

[0080] In the scattered lens 4 of the modified example 3 shown in Figure 13, the scattering portion 49 is a convex portion 492 that protrudes downward. The convex portion 492 is, for example, a convex lens (microlens) composed of a part of a sphere. As shown in Figure 13, multiple convex portions 492 are provided on the exit surface 402 with gaps between them. However, it is not limited to this, and multiple convex portions 492 may be provided on the exit surface 402 without gaps (for example, in a hexagonal shape as shown in Figure 5, or with their outer peripheries touching as shown in Figure 11).

[0081] In the scattered lens 4 of the modified examples 1 to 3 shown in Figures 11 to 13, similar to the scattered lens 4 of the embodiment, the light emitted from the scattered lens 4 becomes scattered light, thereby reducing brightness unevenness.

[0082] The reflector 5 is not limited to the shapes shown in Figures 2 and 7.

[0083] Figure 14 shows a cross-sectional view of the reflector 5 of modified example 4.

[0084] In the reflector 5 of the modified example 4 shown in Figure 14, the outer surface 51 and the inner surface 52 (reflective surface 50) are curved in a parabolic shape.

[0085] Figure 15 shows a cross-sectional view of the reflector 5 of modified example 5.

[0086] In the reflector 5 of the modified example 5 shown in Figure 15, both the opening surface of the inlet 501 and the opening surface of the outlet 502 are parallel to the horizontal plane. Therefore, the imaginary line X20 connecting the center P1 of the inlet 501 and the center P2 of the outlet 502 is parallel to the central axis X10 of the cylindrical reflector 5, and in this case they coincide.

[0087] The reflectors 5 in the modified versions 4 and 5 shown in Figures 14 and 15, like the reflector 5 in the embodiment, have a reflective surface 50 that reflects (scatters) light from the scattering lens 4 with a certain degree of spread. By scattering light from the scattering lens 4, the reflective surface 50 can reduce brightness unevenness.

[0088] (1.5) Relationship between mean Gaussian scattering angle and mean distance between scattering parts As described above, in the lighting fixture 100 of the embodiment, the scattering lens 4 has a large number of minute scattering parts 49, which makes it possible to reduce brightness unevenness. However, because the scattering parts 49 are formed on the scattering lens 4, the arrangement pattern of the scattering parts 49 may appear as brightness unevenness in the light emitted from the lighting fixture 100.

[0089] Figure 16 shows an image Im1 of the intensity distribution of light emitted from the light source unit 3, passing through the scattering lens 4 and reflected by the reflective surface 50, in the lighting fixture 100 of Reference Example 1, with the inclination angle φ (see Figure 10) set to a predetermined angle (30 degrees). Here, the lighting fixture 100 of Reference Example 1 has substantially the same configuration as the lighting fixture 100 of the embodiment. However, the lighting fixture 100 of Reference Example 1 is equipped with the scattering lens 4 of Modified Example 1 (see Figure 11) as the scattering lens 4. In addition, the lighting fixture 100 of Reference Example 1 is equipped with a reflector 5 that has the same shape as the reflector 5 of Modified Example 4 (see Figure 14), but the reflective surface 50 is configured to reflect light without scattering it.

[0090] Furthermore, Figure 17 shows an image Im2 of the intensity distribution of light emitted from the light source unit 3, passing through the scattering lens 4 and reflected by the reflective surface 50, in the lighting fixture 100 of Reference Example 2, with the inclination angle φ set to a predetermined angle (30 degrees). The lighting fixture 100 of Reference Example 2 has substantially the same configuration as the lighting fixture 100 of the embodiment. However, the lighting fixture 100 of Reference Example 2 is equipped with the scattering lens 4 of Modified Example 1 (see Figure 11) as the scattering lens 4. In addition, the lighting fixture 100 of Reference Example 1 is equipped with a reflector 5 that has the same shape as the reflector 5 of the embodiment (see Figures 5 and 6), but the reflective surface 50 is configured to reflect light without scattering it.

[0091] Figures 16 and 17 show images obtained by a luminance meter placed at a predetermined distance (e.g., 40 mm) from the lower end of the reflector 5 (e.g., 120 mm from the light source 32). Figures 16 and 17 also show the intensity scale bar Sc1.

[0092] As shown in region A10 of Figure 16 and region A20 of Figure 17, in the lighting fixtures 100 of Reference Example 1 and Reference Example 2, the light reflected by the reflective surface 50 of the reflector 5 exhibits streaky patterns (luminance unevenness) caused by the pattern of the scattering portion 49.

[0093] To reduce such streaky patterns (brightness unevenness) caused by the pattern of the scattering portion 49, one could, for example, adjust the size of the recesses 491, which are the scattering portions 49 (i.e., the spacing between the scattering portions 49) to make the patterns less noticeable. However, as schematically shown in Figure 18, when the angle between the scattering lens 4 and the reflector 5 can be changed, as in the lighting fixture 100 of this embodiment, the spacing d1 between light rays after they have passed through adjacent scattering portions 49 (microlenses) and been reflected by the reflective surface 50 changes depending on the angle between the scattering lens 4 and the reflector 5. Therefore, even if the spacing between the scattering portions 49 is adjusted so that brightness unevenness is less noticeable when the angle between the scattering lens 4 and the reflector 5 is at a certain angle (first angle) (for example, the state shown in the left diagram of Figure 18), brightness unevenness may reappear when the angle between the scattering lens 4 and the reflector 5 is at a second angle (≠ first angle) (for example, the state shown in the right diagram of Figure 18). Therefore, in a universal downlight like the lighting fixture 100 of this embodiment, it is difficult to reduce brightness unevenness simply by adjusting the spacing between the scattering parts 49 (average distance L0 between the scattering parts 49).

[0094] Therefore, in the lighting fixture 100 of this embodiment, the scattering lens 4 and reflector 5 are designed such that the ratio M = L0 / σ1 between the average Gaussian scattering angle σ1 and the average distance L0 between the scattering parts 49 satisfies the relationship M < 3, thereby reducing brightness unevenness. This point will be explained below with reference to Tables 1 to 4.

[0095] Table 1 shows experimental results in which lighting fixtures similar in structure to the lighting fixture 100 of Reference Example 1 were fabricated by changing the average Gaussian scattering angle σ1 of the reflector 5 and the average distance L0 of the scattering part 49 of the scattering lens 4, and the presence or absence of brightness unevenness was visually determined based on an image of the intensity distribution of light reflected by the reflective surface 50 (see image Im1 in Figure 16).

[0096] Table 2 shows experimental results in which lighting fixtures similar in structure to the lighting fixture 100 of Reference Example 2 were fabricated by changing the average Gaussian scattering angle σ1 of the reflector 5 and the average distance L0 of the scattering part 49 of the scattering lens 4, and the presence or absence of brightness unevenness was visually determined based on an image of the intensity distribution of light reflected by the reflective surface 50 (see image Im2 in Figure 17).

[0097] [Table 1]

[0098] [Table 2]

[0099] In Tables 1 and 2, the horizontal rows represent the average distance L0 [mm] of the scattering portion 49 of the scattering lens 4. The vertical columns in Tables 1 and 2 represent the average Gaussian scattering angle σ1 [degree] of the reflector 5. In Tables 1 and 2, "○" indicates the presence of brightness unevenness, while "×" indicates the absence of brightness unevenness.

[0100] As shown in Tables 1 and 2, brightness unevenness is more likely to appear as the average distance L0 of the scattering portion 49 of the scattering lens 4 increases, and as the average Gaussian scattering angle σ1 of the reflector 5 decreases.

[0101] Tables 3 and 4 also show the calculation results for the ratio M = L0 / σ1, which is the ratio of the average Gaussian scattering angle σ1 to the average distance L0 between the scattering parts 49. In Tables 3 and 4, as in Tables 1 and 2, the horizontal rows represent the average distance L0 [mm] of the scattering parts 49 of the scattering lens 4, and the vertical columns represent the average Gaussian scattering angle σ1 [degree] of the reflector 5.

[0102] In Table 3, cells that were determined to have "×: Brightness unevenness present" in the judgment results for the presence or absence of brightness unevenness for lighting fixture 100 in Reference Example 1 (see Table 1) are shaded.

[0103] Furthermore, in Table 4, cells that were determined to have "×: Brightness unevenness present" in the judgment results for the presence or absence of brightness unevenness for lighting fixture 100 in Reference Example 2 (see Table 2) are shaded.

[0104] [Table 3]

[0105] [Table 4]

[0106] Tables 3 and 4 show that, regardless of whether the lighting fixture 100 is from Reference Example 1 or Reference Example 2 (i.e., regardless of the shape of the reflector 5), lighting fixture 100 that satisfies the above-mentioned ratio M=L0 / σ1 is M<3 has no brightness unevenness. In other words, in lighting fixture 100, brightness unevenness can be reduced by the ratio M=L0 / σ1, which is the ratio of the average Gaussian scattering angle σ1 to the average distance L0 between the scattering parts 49, satisfying a specific relationship (M<3).

[0107] Furthermore, in the lighting fixture 100 of this embodiment, the above ratio M = L0 / σ1 satisfies the relationship M < 3 (the scattering lens 4 and reflector 5 are designed to satisfy this). As a result, the lighting fixture 100 of this embodiment can reduce brightness unevenness.

[0108] Furthermore, experiments conducted by the inventors have shown that changing the depth of the recesses 491 that make up the scattering portion 49 has little effect on the presence or absence of brightness unevenness.

[0109] As a criterion for determining the presence or absence of the above-mentioned brightness unevenness, the following first and / or second criteria may be used instead of, or in addition to, visual inspection.

[0110] The first criterion is the result of determining whether the interval W1 (see Figure 20) between maximum intensity values ​​on a predetermined straight line B1 in the image Im3 (see Figure 19) of the light intensity distribution on the reflective surface 50 is greater than or equal to a predetermined value. In the first criterion, if the interval W1 between maximum intensity values ​​is greater than or equal to the predetermined value, it is determined that there is brightness unevenness, and if the interval W1 between maximum intensity values ​​is less than the predetermined value, it may be determined that there is no brightness unevenness. The predetermined value is not particularly limited, but can be selected from a range of approximately 0.2 mm to 0.5 mm, for example. That is, if the interval W1 of relatively bright areas (areas where the intensity is at its maximum) on the reflective surface 50 is greater than or equal to the predetermined value, when that light reaches the floor surface, it may be perceived as brightness unevenness by a person. Therefore, the interval W1 between maximum intensity values ​​can be adopted as a criterion for determining the presence or absence of brightness unevenness.

[0111] The first criterion may also be the result of whether or not the interval W2 (see Figure 20) between minimums of intensity on a predetermined straight line B1 in the image Im3 (see Figure 19) of the light intensity distribution on the reflective surface 50 is greater than or equal to a predetermined value. In the first criterion, if the interval W2 between minimums is greater than or equal to a predetermined value, it may be determined that there is brightness unevenness, and if the interval W2 between minimums is less than a predetermined value, it may be determined that there is no brightness unevenness. The predetermined value is not particularly limited, but can be selected from a range of, for example, 0.2 mm to 0.5 mm. That is, if the interval W2 of relatively dark areas (areas where the intensity is minimum) on the reflective surface 50 is greater than or equal to a predetermined value, when that light reaches the floor surface, it may be perceived as brightness unevenness by a person. For this reason, the interval W2 between minimums of intensity can be adopted as a criterion for determining the presence or absence of brightness unevenness.

[0112] The second criterion is the maximum intensity I on a predetermined straight line B1 in the image Im3 (see Figure 19) of the light intensity distribution on the reflective surface 50. max (See Figure 20) Minimum value I min (See Figure 20) Ratio (=I min / I max) is the result of whether it is below the threshold value. In the second determination criterion, if the above ratio is below the threshold value, it is determined that there is luminance unevenness, and if the above ratio is greater than the threshold value, it can be determined that there is no luminance unevenness. The threshold value is not particularly limited, but can be selected from, for example, within the range of about 0.6 to 0.75. That is, on the reflecting surface 50, if the ratio between the brightest part and the darkest part is below the threshold value, when the light reaches the floor surface, it can be recognized by people as luminance unevenness. Therefore, as the determination criterion for the presence or absence of luminance unevenness, the ratio of the maximum value I max to the minimum value I min (= I min / I max ) can be adopted.

[0113] Note that as the predetermined straight line B1, for example, a straight line is drawn within the image Im3, and the ratio of the minimum value I max to the maximum value I min (= I min / I max ) is calculated, and the straight line for which the calculated ratio (intensity ratio) becomes the largest can be selected.

[0114] Also, the first determination criterion and the second determination criterion may use a logical sum or a logical product. That is, when at least one of the first determination criterion and the second determination criterion is satisfied, it may be determined that there is luminance unevenness, or when both the first determination criterion and the second determination criterion are satisfied, it may be determined that there is luminance unevenness.

[0115] (2) Variation The embodiment of the present disclosure is not limited to the above embodiment. The above embodiment can be variously modified according to design and the like as long as the object of the present disclosure can be achieved.

[0116] In one variation, the lighting fixture 100 is not limited to a universal downlight, and any lighting fixture with a variable angle between the diffusing lens and the reflector may be used.

[0117] In one modified example, the light source unit 3 may include multiple light sources 32. The multiple light sources 32 may include, for example, two or more light sources 32 that emit light in colors different from each other.

[0118] (3) Appearance Based on the embodiments described above, the following aspects are disclosed.

[0119] The first embodiment of the lighting fixture (100) comprises a light source (32), a scattering lens (4), a reflector (5), and an angle changing mechanism (8). The scattering lens (4) has a plurality of scattering parts (49) for scattering light. The reflector (5) has a reflective surface (50) that reflects the light emitted from the scattering lens (4). The angle changing mechanism (8) changes the angle between the reflector (5) and the scattering lens (4). In the lighting fixture (100), when the average Gaussian scattering angle of the reflective surface (50) of the reflector (5) is σ1 [degree] and the average distance between adjacent scattering parts (49) is L0 [mm], the ratio of the average distance to the average Gaussian scattering angle M = L0 / σ1 satisfies the relationship M < 3.

[0120] According to this embodiment, it is possible to reduce brightness unevenness.

[0121] In the second embodiment of the lighting fixture (100), the reflective surface (50) is made of a thin aluminum film on which aluminum has been deposited.

[0122] According to this embodiment, it is possible to reduce brightness unevenness.

[0123] In the third embodiment of the lighting fixture (100), each of the plurality of scattering parts (49) is a microlens, as in the first or second embodiment.

[0124] According to this embodiment, it is possible to reduce brightness unevenness.

[0125] In the fourth embodiment of the lighting fixture (100), in the third embodiment, the microlens is a concave lens including a recess (491) provided on the emission surface (402) of the scattering lens (4).

[0126] According to this embodiment, it is possible to reduce brightness unevenness.

[0127] In the fifth embodiment of the lighting fixture (100), in the third embodiment, the microlens is a convex lens including a protrusion (492) provided on the emission surface (402) of the scattering lens (4).

[0128] According to this embodiment, it is possible to reduce brightness unevenness. [Explanation of symbols]

[0129] 100 lighting fixtures 32 light source 4. Scattering lens 402 Ejection surface 49 Scatter part 491 recess 492 Convex part 5 Reflectors 50 reflective surface 8 Angle adjustment mechanism

Claims

1. Light source and A scattering lens having multiple scattering parts for scattering light, A reflector having a reflective surface that reflects light emitted from the scattering lens, The system includes an angle changing mechanism that changes the angle between the reflector and the scattering lens, When the average Gaussian scattering angle of the reflecting surface of the reflector is σ1 [degree], and the average distance between adjacent scattering parts among the plurality of scattering parts is L0 [mm], the ratio of the average distance to the average Gaussian scattering angle M = L0 / σ1 satisfies the relationship M < 3. Lighting fixtures.

2. The reflective surface is composed of an aluminum thin film formed by depositing aluminum. The lighting fixture according to claim 1.

3. Each of the aforementioned multiple scattering parts is a microlens. A lighting fixture according to claim 1 or 2.

4. The microlens is a concave lens including a recess provided on the emission surface of the scattering lens. The lighting fixture according to claim 3.

5. The microlens is a convex lens including a protrusion provided on the emission surface of the scattering lens. The lighting fixture according to claim 3.

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