Lens and lighting fixture

Abstract

To provide a lens and a lighting fixture capable of achieving both diffusion of light to be emitted and high efficiency.SOLUTION: A lens 6 allows light emitted from a light source 42 of a lighting fixture 1 to pass therethrough. The lens 6 comprises an incidence plane 61 where the light is incident thereon and an output plane 62 where the light is emitted therethrough. The incidence plane 61 has a concave plane 611 and a convex plane 612 surrounding the concave plane 611.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present disclosure relates to a lens and a lighting fixture.

Background Art

[0002] A lighting fixture such as Patent Document 1 includes a light flux control member that controls the light distribution of light emitted from a light-emitting element, and a light diffusion plate that diffuses and transmits the light emitted from the light flux control member.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Some lighting fixtures are required to diffuse light and have high-efficiency light distribution. In order to meet such requirements for lighting fixtures, the lenses used in conventional lighting fixtures are required to achieve both diffusion of the emitted light and high efficiency. However, it has been difficult for the lenses used in conventional lighting fixtures to meet such requirements.

[0005] An object of the present disclosure is to provide a lens and a lighting fixture that enable both diffusion of the emitted light and high efficiency.

Means for Solving the Problems

[0006] A lens according to one aspect of the present disclosure is a lens through which light emitted from a light source of a lighting fixture passes, and includes an incident surface on which the light is incident and an exit surface from which the light exits. The incident surface has a concave curved surface and a convex curved surface surrounding the concave curved surface. At least a part of the exit surface is a flat surface having a dimpled portion with a concavo-convex shape. The convex curved surface is an annular shape surrounding the concave curved surface. The top of the convex curved surface is formed at a position closer to the outer peripheral edge of the convex curved surface than the inner peripheral edge of the convex curved surface. A lens according to another aspect of the present disclosure is a lens through which light emitted from a light source of a lighting fixture passes, and includes an incident surface on which the light is incident, an exit surface from which the light exits, and a Fresnel lens. The incident surface has a concave curved surface and a convex curved surface surrounding the concave curved surface. The Fresnel lens includes a plurality of cylindrical lenses having a sawtooth-wave-shaped cross section, which are arranged concentrically surrounding the convex curved surface.

[0007] The lighting fixture according to one aspect of the present disclosure includes the above-described lens, the light source, and a reflecting member that reflects a part of the light emitted from the emission surface. A lighting fixture according to another aspect of the present disclosure includes a light source, a lens, and a reflecting member. Light emitted from the light source passes through the lens. The lens includes an incident surface on which the light is incident and an exit surface from which the light exits. The incident surface has a concave curved surface and a convex curved surface surrounding the concave curved surface. The convex curved surface is an annular shape surrounding the concave curved surface. The top of the convex curved surface is formed at a position closer to the outer peripheral edge of the convex curved surface than the inner peripheral edge of the convex curved surface. The reflecting member reflects a part of the light emitted from the exit surface.

Advantages of the Invention

[0008] The present disclosure has an effect of enabling both diffusion of emitted light and high efficiency.

Brief Description of the Drawings

[0009]

Figure 1

Figure 2

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Figure 14

DETAILED DESCRIPTION OF THE INVENTION

[0010] The following embodiments generally relate to a lens and a lighting fixture. More specifically, the present invention relates to a lens and a lighting fixture that enable both diffusion and high efficiency of emitted light.

[0011] Hereinafter, the lens and the lighting fixture according to the embodiments will be described in detail with reference to FIGS. 1 to 7. However, each figure described in the following embodiments is a schematic diagram, and the ratio of the size and thickness of each component does not necessarily reflect the actual dimensional ratio. Note that the configurations described in the following embodiments are merely examples of the present disclosure. The present disclosure is not limited to the following embodiments, and various modifications can be made according to the design and the like as long as the effects of the present disclosure can be achieved.

[0012] In the following description, unless otherwise specified, the X-axis, Y-axis, and Z-axis orthogonal to each other are defined in FIG. 1. For convenience, one of the two directions along the X-axis is defined as the right direction, and the other is defined as the left direction. Also, one of the two directions along the Y-axis is defined as the front direction, and the other is defined as the back direction. Further, one of the two directions along the Z-axis is defined as the upward direction, and the other is defined as the downward direction. Note that these directions do not limit the actual directions of use of the lens and the lighting fixture.

[0013] (Embodiment) (1) Lighting Fixture The configuration of the lighting fixture 1 according to the embodiment will be described with reference to the drawings.

[0014] The lighting fixture 1 is installed, for example, in a store, office, theater, commercial facility, hall, or house. The lighting fixture 1 is, for example, a recessed downlight, which is embedded in a building material such as a ceiling panel and illuminates downward.

[0015] As shown in FIGS. 1 to 3, the lighting fixture 1 includes a base 2, a light source holder 3, a light source unit 4, a main reflection member 5, a lens 6, a frame body 7, and an auxiliary reflection member 8.

[0016] (1.1) Base The base 2 includes a cylindrical body 21, and the upper end of the cylindrical body 21 is closed by an upper wall 211. The lower end of the cylindrical body 21 is open, and a light source holder 3 is housed inside the cylindrical body 21. A plurality of heat dissipation fins 22 protruding upward are formed on the upper surface of the upper wall 211. Three insertion holes 213 (see FIG. 1) are formed on the upper surface of the upper wall 211, and three screws (not shown) are respectively inserted through the three insertion holes 213. By screwing the lower ends of the three screws into the screw holes 731 (see FIG. 3) of the frame body 7, the light source holder 3, the light source unit 4, the main reflection member 5, and the frame body 7 are attached to the base 2.

[0017] A quadrangular pyramid-shaped protrusion 212 protruding downward is formed on the lower surface of the upper wall 211. The upper surface of the LED substrate 41 of the light source unit 4 contacts the protrusion 212. That is, the base 2 functions as a heat dissipation member that dissipates the heat generated by the light source 42 mounted on the LED substrate 41 to the surroundings, and is preferably formed of a metal having a high thermal conductivity such as aluminum, copper, or iron. The cylindrical body 21 and the heat dissipation fins 22 may be integrally formed by die casting or the like, or may be configured such that the separate cylindrical body 21 and heat dissipation fins 22 are integrated by bonding or the like. Note that the base 2 may not include the heat dissipation fins 22.

[0018] (1.2) Light source holder The light source holder 3 includes a holder body 31 having a substantially rectangular plate shape, and a cylindrical side wall 32 formed to extend upward and downward from the periphery of the holder body 31. A recess 311 recessed upward is formed at the center of the lower surface of the holder body 31. The recess 311 has a square cross section. A square opening 312 is formed on the square bottom surface of the recess 311.

[0019] The light source holder 3 is housed inside the cylindrical body 21 of the base 2, and the upper end of the side wall 32 and the bottom of the recess 311 are in contact with the lower surface of the upper wall 211 of the cylindrical body 21.

[0020] In the recess 311 of the light source holder 3, the LED substrate 41 of the light source unit 4 is housed, and the protrusion 212 of the base 2 is inserted through the opening 312 from above and is in surface contact with the upper surface of the LED substrate 41.

[0021] (1.3) Light source unit The light source unit 4 includes an LED substrate 41, a light source 42, and a pair of electrodes 43.

[0022] The LED substrate 41 and the light source 42 constitute a COB (Chip On Board) type LED (Light Emitting Diode) chip.

[0023] The LED substrate 41 has a square plate shape and, for example, is made of a ceramic substrate, a resin substrate, or a metal base substrate. The LED substrate 41 has the light source 42 and a pair of electrodes 43 mounted thereon.

[0024] The light source 42 includes a plurality of LED chips, and the plurality of LED chips are mounted in a circular shape on the lower surface of the LED substrate 41 and are sealed with a sealing member. The LED chip is, for example, a bare chip that emits monochromatic visible light such as a blue LED chip that emits blue light. Note that the light source 42 may be configured to include one LED chip. The sealing member is made of, for example, a translucent resin and contains a phosphor. The phosphor has a function of wavelength-converting the light from the LED chip. The sealing member is, for example, a silicone resin containing phosphor particles. If the LED chip emits blue light and the phosphor particles are YAG-based yellow phosphors, the light source 42 emits white light. The sealing member may seal all the LED chips together, may seal the plurality of LED chips arranged in a matrix in a line for each column, or may seal each of the plurality of LED chips individually.

[0025] The pair of electrodes 43 are formed of a highly conductive material such as copper or aluminum and are mounted on the LED substrate 41. A wire or conductor that serves as a supply path for external DC power is connected to the pair of electrodes 43. The light source 42 is supplied with DC power via the pair of electrodes 43 and is lit by the DC power.

[0026] Also, the LED substrate 41 may be equipped with a power supply circuit that converts external AC power into DC power. In this case, a wire or conductor that serves as a supply path for external AC power is connected to the pair of electrodes 43. The light source 42 is lit by the DC power output by the power supply circuit.

[0027] The LED substrate 41 of the light source unit 4 is housed in the recess 311 of the light source holder 3 with the light source 42 facing downward, and the upper surface of the LED substrate 41 is in surface contact with the protrusion 212 of the base 2 that has passed through the opening 312 of the light source holder 3 from above. Therefore, the heat generated by the light source 42 is transmitted to the base 2 via the protrusion 212 and dissipated to the surroundings from the heat dissipation fins 22 of the base 2 and the like.

[0028] (1.4) Reflective member The main reflective member 5 includes a cylindrical body 51 having an axial direction along the vertical direction along the Z-axis, and an annular flange portion 52 provided on the outer peripheral surface of the body 51. The main reflective member 5 is formed of, for example, a white resin material. The resin material constituting the main reflective member 5 is preferably polybutylene terephthalate or the like. Note that the main reflective member 5 may be formed of a metal material such as aluminum, or may be a resin molded product with a metal film such as aluminum formed on the inner surface.

[0029] The cylinder body 51 integrally includes a cylindrical upper cylinder part 511 and a cylindrical lower cylinder part 512, and has a two-stage structure in which the diameter of the lower cylinder part 512 is larger than that of the upper cylinder part 511. The upper cylinder part 511 is located below the light source 42 of the light source unit 4, and the light source 42 is located at the upper part (or near the upper end) of the upper cylinder part 511. The inner surfaces of the upper cylinder part 511 and the lower cylinder part 512 are light reflection surfaces. The light emitted downward by the light source 42 passes through the inside of the upper cylinder part 511 and then through the inside of the lower cylinder part 512 and enters the lens 6. A part of the light passing through the inside of the upper cylinder part 511 is reflected by the inner surface of the upper cylinder part 511. A part of the light passing through the inside of the lower cylinder part 512 is reflected by the inner surface of the lower cylinder part 512.

[0030] The flange part 52 includes an annular part 521 and a side wall 522. The annular part 521 is annular and extends outward from the upper end of the lower cylinder part 512 on the outer peripheral surface of the lower cylinder part 512. The side wall 522 is an annular wall body extending upward from the outer peripheral edge of the annular part 521. Further, three locking parts 523 are formed at equal intervals in the circumferential direction on the lower surface of the annular part 521. The locking part 523 is composed of a pair of locking claws extending downward from the lower surface of the annular part 521. By locking the locking part 523 to a locking protrusion (not shown) of the lens 6, the lens 6 is attached to the lower end of the main reflection member 5.

[0031] (1.5) Lens The lens 6 is a translucent member having translucency, and is housed in the lower cylinder part 512 so as to cover the lower end opening of the lower cylinder part 512 of the main reflection member 5. The lens 6 transmits the light that has passed through the inside of the main reflection member 5 from the light source 42 and reaches the lens 6.

[0032] As shown in FIGS. 4 and 5, the lens 6 includes a disc-shaped lens body 60. The upper surface of the lens body 60 constitutes an incident surface 61 on which light from the light source 42 is incident. The lower surface of the lens body 60 constitutes an emission surface 62 through which the light that has passed through the lens 6 is emitted to the outside of the lens 6.

[0033] The incident surface 61 has a concave curved surface 611 and a convex curved surface 612 surrounding the concave curved surface 611. The incident surface 61 further has a boundary portion 614 serving as a boundary between the concave curved surface 611 and the convex curved surface 612 between the concave curved surface 611 and the convex curved surface 612. The incident surface 61 further has a Fresnel lens 613 surrounding the convex curved surface 612. That is, an annular Fresnel lens 613 is formed along the outer periphery of the incident surface 61. On the inner peripheral side of the Fresnel lens 613 on the incident surface 61, the convex curved surface 612 is formed. On the inner peripheral side of the convex curved surface 612 on the incident surface 61, the boundary portion 614 is formed. On the inner peripheral side of the boundary portion 614 on the incident surface 61, the concave curved surface 611 is formed.

[0034] The lens 6 is made of a light-transmissive material having light-transmittance, and is formed of, for example, a transparent resin material such as acrylic, silicone resin material, or polycarbonate, or a glass material.

[0035] Details of the lens 6 will be described later.

[0036] (1.6) Frame The frame 7 is formed in a cylindrical shape by resin or the like, and includes a cylindrical body 71, a flange portion 72, and three mounting pieces 73 (only one mounting piece 73 is shown in FIG. 3). The cylindrical body 71 has a cylindrical shape with the vertical direction along the Z axis as the axial direction. A circular upper opening 711 is formed on the upper surface of the cylindrical body 71, and a circular lower opening 712 is formed on the lower surface of the cylindrical body 71. The lower cylindrical portion 512 of the main reflecting member 5 passes through the upper opening 711 from above, and the lower cylindrical portion 512 is housed in the cylindrical body 71.

[0037] The flange portion 72 is formed in an annular shape at the lower end of the cylindrical body 71 and extends from the opening edge of the lower opening 712 toward the outside of the cylindrical body 71.

[0038] The three mounting pieces 73 are formed at equal intervals in the circumferential direction of the upper opening 711 at the upper end of the cylindrical body 71.

[0039] Furthermore, the attachment piece 73 is formed with a screw hole 731 (only one screw hole 731 is shown in FIG. 3). Then, the lower ends of three screws (not shown) inserted into the three insertion holes 213 (see FIG. 1) of the base 2 from above are screwed into the screw holes 731 respectively, so that the light source holder 3, the light source unit 4, the main reflection member 5, and the frame body 7 are attached to the base 2. That is, the base 2 and the frame body 7 sandwich the light source holder 3, the light source unit 4, and the main reflection member 5.

[0040] (1.7) Auxiliary reflection member The auxiliary reflection member 8 corresponds to the reflection member of the present disclosure and is attached inside the frame body 7. The auxiliary reflection member 8 includes a cylindrical body 81 and three bending pieces 82.

[0041] The cylindrical body 81 has a cylindrical shape. The circular opening formed at the upper end of the cylindrical body 81 is used as the incident port 811, and the circular opening formed at the lower surface of the cylindrical body 81 is used as the exit port 812. The diameter of the cylindrical body 81 gradually increases as it approaches the lower end from the upper end. That is, the diameter of the exit port 812 is larger than the diameter of the incident port 811. The upper end of the cylindrical body 81 supports the periphery of the exit surface 62 of the lens 6, and the lower end of the lower cylindrical portion 512 of the main reflection member 5 abuts against the incident surface 61, so that the lens 6 is sandwiched between the main reflection member 5 and the auxiliary reflection member 8.

[0042] Three bending pieces 82 are formed at equal intervals along the periphery of the incident port 811 at the upper end of the cylindrical body 81. The bending piece 82 extends upward from the periphery of the incident port 811, and a locking piece 821 extends outward from the upper end of the bending piece 82.

[0043] The auxiliary reflection member 8 is housed inside the frame body 7 such that the axial direction of the cylindrical body 81 is along the vertical direction. The upper end of the auxiliary reflection member 8 is inserted into the inside of the frame body 7 from the lower opening 712 of the frame body 7. When the auxiliary reflection member 8 is inserted into the inside of the frame body 7, the bending piece 82 bends and passes through the upper opening 711 from below, and the lower surface of the locking piece 821 is locked to the upper surface of the attachment piece 73. That is, the auxiliary reflection member 8 is attached to the frame body 7.

[0044] The inner surface of the cylinder 81 constitutes a reflecting surface 813 that reflects light. The auxiliary reflecting member 8 provided with the reflecting surface 813 is preferably a resin cylinder with aluminum vapor-deposited on its surface. The aluminum cylinder may be any of a machined product, a cast product, and a forged product. Further, the auxiliary reflecting member 8 may be a resin cylinder with a metal film such as aluminum vapor-deposited on its surface. Examples of the resin material constituting the auxiliary reflecting member 8 include polybutylene terephthalate.

[0045] (1.8) Illumination light In the lighting fixture 1 configured as described above, the light emitted by the light source 42 passes through the inside of the cylinder 51 of the main reflecting member 5 and is incident on the incident surface 61 of the lens 6. The light incident on the incident surface 61 passes through the inside of the lens 6 and is emitted from the emission surface 62 of the lens 6. The emission surface 62 is a plane parallel to the X-Y plane (the plane defined by the X-axis and Y-axis in FIG. 1). The light emitted from the emission surface 62 is incident on the inside of the cylinder 81 through the entrance 811 of the auxiliary reflecting member 8. That is, the light emitted by the light source 42 of the light source unit 4 reaches the inside of the cylinder 81 through the main reflecting member 5 and the lens 6. Among the light that reaches the inside of the cylinder 81, the light reflected at least once by the reflecting surface 813 is defined as the reflected light. Among the light that reaches the inside of the cylinder 81, the light that has not been reflected by the reflecting surface 813 even once is defined as the direct light. From the exit 812, illumination light including the reflected light and the direct light is output toward the illumination space below the lighting fixture 1. That is, the lighting fixture 1 irradiates illumination light from the exit 812.

[0046] (2) Details of the lens The lens 6 controls the light distribution of the light emitted by the light source 42, diffuses the illumination light, and emits it from the exit 812. However, the light reflected by the reflecting surface 813 among the light emitted from the lens 6 becomes a factor causing glare when viewed from the lower illumination space. Therefore, by using the Fresnel lens 613, it is difficult for light to hit the reflecting surface 813, suppressing glare.

[0047] For example, as the lens using the Fresnel lens 613, there is the lens 6R of the following first comparative example or the lens 6S of the second comparative example. Note that the first comparative example and the second comparative example are different from this embodiment.

[0048] (2.1) First Comparative Example FIGS. 6A and 6B show the optical path of the lighting fixture of the first comparative example using the lens 6R different from the lens 6 of this embodiment. Note that FIGS. 6A and 6B illustrate only the light source 42, the lens 6R, and the cylindrical body 81 of the auxiliary reflection member 8. The components of the lens 6R that are the same as those of the lens 6 are denoted by the same reference numerals as the lens 6.

[0049] The lens 6R is a lens in which the concave curved surface 611 and the convex curved surface 612 of the incident surface 61 of the lens 6 are changed to a plane 68. The plane 68 is a plane parallel to the X-Y plane.

[0050] That is, in the incident surface 61 of the lens 6R, the circular plane 68 is surrounded by the annular Fresnel lens 613. Then, as shown in FIG. 6A, among the light emitted from the center of the light source 42, the light incident on the plane 68 is emitted from the exit surface 62 in a direction away from the central axis of the cylindrical body 81 (spreading direction) (see the light L11 in FIG. 6A). Among the light emitted from the center of the light source 42, the light incident on the Fresnel lens 613 is reflected by the Fresnel lens 613 and is emitted in a direction toward the central axis of the cylindrical body 81 (condensing direction) (see the light L12 in FIG. 6A). That is, the Fresnel lens 613 has a function of suppressing the occurrence of glare by performing cross-light distribution in which the light L12 is emitted in a direction intersecting the light L11, so that the light incident near the outer peripheral edge of the lens 6R does not hit the reflecting surface 813.

[0051] Also, in the lens 6R provided with the plane 68 on the incident surface 61, as shown in FIG. 6B, the light L13 that is incident near the outer peripheral edge of the plane 68 and is emitted from the exit surface 62 is emitted from the exit port 812 without hitting the reflecting surface 813.

[0052] FIG. 7 shows the light distribution curve of the lighting fixture of the first comparative example using the lens 6R. In the first comparative example, since the degree of diffusion of the light emitted from the lens 6R is low and the beam angle is also narrow, it has a peak in luminous intensity in the directly downward direction, and the 1 / 2 beam angle is relatively small (narrow).

[0053] (2.2) Second Comparative Example FIGS. 8A and 8B show the optical paths of the lighting fixture of the second comparative example using a lens 6S different from the lens 6 of the present embodiment. Note that FIGS. 8A and 8B only show the light source 42, the lens 6S, and the cylindrical body 81 of the auxiliary reflection member 8. Components of the lens 6S that are the same as those of the lens 6 are denoted by the same reference numerals as the lens 6.

[0054] The lens 6S is a lens in which the concave curved surface 611 and the convex curved surface 612 of the incident surface 61 of the lens 6 are changed to a concave curved surface 69, thereby expanding the light distribution range of the emitted light more than that of the lens 6R. The concave curved surface 69 is a curved surface that is recessed downward from the incident surface 61.

[0055] That is, on the incident surface 61 of the lens 6S, a circular concave curved surface 69 is surrounded by an annular Fresnel lens 613. Then, as shown in FIG. 8A, among the light emitted from the center of the light source 42, the light incident on the concave curved surface 69 is emitted from the emission surface 62 while spreading in a more spreading direction than the lens 6R (see the light L21 in FIG. 8A). Among the light emitted from the center of the light source 42, the light incident on the Fresnel lens 613 is reflected by the Fresnel lens 613 and emitted in the condensing direction (see the light L22 in FIG. 8A).

[0056] Also, in the second comparative example, since the light emitted from the lens 6S spreads too much, as shown in FIG. 8B, the light L23 that is incident near the outer peripheral edge of the concave curved surface 69 and emitted from the emission surface 62 hits the reflecting surface 813. The light L23 hitting the reflecting surface 813 becomes a cause of glare.

[0057] FIG. 9 shows the light distribution curve of the lighting fixture of the second comparative example using the lens 6S. In the light distribution curve of the second comparative example, due to the light L23 reflected by the reflecting surface 813, the peak of the luminous intensity as viewed from directly below is larger than that of the first comparative example, and the 1 / 2 beam angle is even smaller than that of the first comparative example.

[0058] (2.3) Lens of the Embodiment Each of the lighting fixtures of the first and second comparative examples described above performs cross-light distribution by the Fresnel lens 613, thereby reducing the amount of light reflected by the reflecting surface 813 and suppressing the generation of glare. However, in the lighting fixture of the first comparative example using the lens 6R, the 1 / 2 beam angle was small. Further, in the lighting fixture of the second comparative example using the lens 6S, compared with the first comparative example, the 1 / 2 beam angle is even smaller, and the amount of light hitting the reflecting surface 813 increases, making glare more likely to occur and the light distribution efficiency lower. That is, for the lighting fixture 1 (especially a downlight) in which the auxiliary reflecting member 8 is disposed on the emission side of the lens 6, it is required to increase (widen) the 1 / 2 beam angle and suppress the generation of glare to perform light distribution with high efficiency. In other words, it is required to achieve both diffusion of the emitted light and high efficiency.

[0059] Therefore, the lighting fixture 1 of the present embodiment includes the lens 6 shown in FIGS. 4 and 5.

[0060] The lens 6 includes a disk-shaped lens body 60. The upper surface of the lens body 60 is the incident surface 61, and the lower surface of the lens body 60 is the emission surface 62.

[0061] The incident surface 61 has a concave curved surface 611 and a convex curved surface 612 surrounding the concave curved surface 611. The incident surface 61 further has a boundary portion 614 that is the boundary between the concave curved surface 611 and the convex curved surface 612 between the concave curved surface 611 and the convex curved surface 612. The incident surface 61 further has a Fresnel lens 613 surrounding the convex curved surface 612.

[0062] The concave surface 611 is a region where the center of the incident surface 61 is recessed downward, and it is a circular curved surface. The vertex 611a of the concave surface 611 is located at the center of the circular incident surface 61. The vertex 611a is located at the lowest position of the concave surface 611. And the concave surface 611 is formed axially symmetric with respect to the virtual axis Za1 that extends vertically along the Z-axis passing through the vertex 611a, and is formed inside the circular outer peripheral edge 611b that surrounds the vertex 611a.

[0063] The convex surface 612 is a region where the outside of the incident surface 61 protrudes upward, and it is an annular curved surface. The convex surface 612 is formed axially symmetric with respect to the virtual axis Za1, and is formed between the circular inner peripheral edge 612b that surrounds the vertex 611a and the outer peripheral edge 612c that surrounds the inner peripheral edge 612b. The top 612a of the convex surface 612 is in an annular shape located at the highest position of the convex surface 612. The top 612a is formed at a position closer to the outer peripheral edge 612c than the inner peripheral edge 612b.

[0064] An annular boundary portion 614 is formed between the outer peripheral edge 611b of the concave surface 611 and the inner peripheral edge 612b of the convex surface 612. The boundary portion 614 is composed of a curved surface so that the concave surface 611 and the convex surface 612 are continuous and smooth (so as not to be discontinuous). That is, the boundary portion 614 is a curved surface that connects the outer peripheral edge 611b of the concave surface 611 and the inner peripheral edge 612b of the convex surface 612. As a result, the lens 6 can smoothly connect the light distribution by the concave surface 611 and the light distribution by the convex surface 612, and can suppress the sense of incongruity of the light distribution.

[0065] The Fresnel lens 613 is configured by arranging a plurality (two in FIGS. 3 and 4) of annular lenses having a sawtooth-shaped cross section concentrically around the convex surface 612.

[0066] FIGS. 10A and 10B show the optical path of the lens 6. Note that FIGS. 10A and 10B only show the light source 42, the lens 6, and the cylindrical body 81 of the auxiliary reflection member 8.

[0067] As shown in FIG. 10A, among the light emitted from the center of the light source 42, the light incident on the concave surface 611 exits from the exit surface 62 while spreading in a direction away from the central axis of the cylindrical body 81 (spreading direction) (see the light L1 in FIG. 10A). At this time, the light incident on the concave surface 611 travels while spreading more from the exit surface 62 than the light incident on the flat surface 68 of the first comparative example. The light exiting from the exit surface 62 spreads more as the depth of the concave surface 611 is deeper. That is, the concave surface 611 diffuses the light incident on the concave surface 611 from the exit surface 62.

[0068] Also, the light incident on the convex surface 612 among the light emitted from the center of the light source 42 is distributed as follows.

[0069] Among the light incident on the convex surface 612, the light incident on the side closer to the center of the lens 6 (the side closer to the concave surface 611) than the top 612a of the convex surface 612 exits from the exit surface 62 while spreading in the spreading direction (see the light L2 in FIGS. 10A and 10B). Among the light incident on the convex surface 612, the light incident on the side closer to the outer peripheral edge of the lens 6 (the side closer to the Fresnel lens 613) than the top 612a of the convex surface 612 exits from the exit surface 62 in a direction approaching the central axis of the cylindrical body 81 (condensing direction) (see the light L3 in FIG. 10B). The degree of light condensation of the light incident on the convex surface 612 increases as the height of the convex surface 612 is higher.

[0070] On the incident surface 61 of the lens 6, the convex surface 612 is surrounded by an annular Fresnel lens 613. Then, as shown in FIG. 10A, the light incident on the Fresnel lens 613 among the light emitted from the center of the light source 42 is reflected by the Fresnel lens 613 and exits in the condensing direction (see the light L4 in FIG. 10A). That is, the Fresnel lens 613 has a function of suppressing the light incident near the outer peripheral edge of the lens 6 from hitting the reflecting surface 813 and suppressing the generation of glare by performing cross-light distribution that emits the light L4 in a direction intersecting the lights L1, L2, and L3.

[0071] That is, the light L1 and L2 emitted from the exit surface 62 by the light incident on the central portion (concave curved surface 611) of the incident surface 61 are spreading in the spreading direction. Further, the light L3 and L4 emitted from the exit surface 62 by the light incident on the outside of the incident surface 61 proceed in the condensing direction. As a result, most of the light emitted from the exit surface 62 is emitted from the exit port 812 without hitting the reflecting surface 813. In other words, the amount of light hitting the reflecting surface 813 is reduced, glare is less likely to occur, and the light distribution efficiency is improved.

[0072] FIG. 11 shows the light distribution curve of the lighting fixture 1 using the lens 6. The luminous intensity in the directly downward direction by the lens 6 is lower than that in the first comparative example (see FIG. 7) using the lens 6R and the second comparative example (see FIG. 9) using the lens 6S. As a result, the 1 / 2 beam angle by the lens 6 becomes larger than that in the first and second comparative examples.

[0073] As described above, the lens 6 of the present embodiment can diffuse the light emitted from the exit surface 62 by the light L1 and L2, and suppress the spread of the light emitted from the exit surface 62 by the light L3 and L4. As a result, the lighting fixture 1 including the lens 6 realizes both diffusion of the emitted light and high efficiency.

[0074] Further, since the top portion 612a of the convex curved surface 612 is formed at a position closer to the outer peripheral edge 612c than the inner peripheral edge 612b, the lens 6 can make the ratio of the light L2 included in the light emitted from the exit surface 62 higher than the ratio of the light L3. That is, the lens 6 can increase the degree of diffusion of light by the convex curved surface 612.

[0075] (3) First Modified Example FIG. 12 shows a lens 6A which is a modified example of the lens 6.

[0076] The lens 6A has a dimpled portion 63 with a concavo-convex shape on the planar emission surface 62. The dimpled portion 63 is formed over the entire area of the circular emission surface 62 and has a number of recesses 631 formed by laser processing or sandblasting. The shape of the recess 631 is preferably hexagonal, but may be other shapes such as circular, elliptical, triangular, or quadrangular. The size of the recess 631 is preferably several millimeters or less. Also, the dimpled portion 63 may be configured to be formed over the entire surface of the circular emission surface 62 or may be formed, for example, concentrically on a part of the circular emission surface 62.

[0077] Since the emission surface 62 is planar, the dimpled portion 63 can be easily formed on the emission surface 62. The dimpled portion 63 suppresses light unevenness and color unevenness of the light emitted from the emission surface 62 by diffusely reflecting the light. Note that the planar surface constituting the emission surface 62 may have fine concavo-convexities according to its surface roughness.

[0078] (4) Second modification FIG. 13 shows a lens 6B which is a modification of the lens 6.

[0079] In the lens 6B, the top 612d of the convex curved surface 612 is formed at a position closer to the inner peripheral edge 612b than the outer peripheral edge 612c. Also, in the lens 6B, the top 612d is located above the top 612a of the embodiment. That is, the convex curved surface 612 of the lens 6B of the second modification protrudes more upward than the lens 6 of the embodiment, and the degree of spread of the light incident on the convex curved surface 612 is more suppressed.

[0080] Then, among the light incident on the convex curved surface 612 of the lens 6B, the light incident on the side closer to the outer peripheral edge of the lens 6B (the side closer to the Fresnel lens 613) than the top 612d is emitted from the emission surface 62 in the condensing direction (see the light L5 in FIG. 14A).

[0081] In the convex surface 612 of this modification example, the region closer to the outer peripheral edge of the lens 6B than the top 612d is wider than that of the above-described embodiment. Therefore, the light L5 (see Fig. 14A) emitted from the emission surface 62 in the condensing direction increases more than the light L2 (see Fig. 10A) of the above-described embodiment. As a result, the lens 6B makes it less likely for the light incident on the convex surface 612 and emitted from the emission surface 62 to hit the reflection surface 813, and can further suppress the occurrence of glare.

[0082] Fig. 14B shows the light distribution curve of the lighting fixture 1 using the lens 6B. In the light distribution curve of the lighting fixture 1 using the lens 6B, the peak of the luminous intensity as viewed from directly below is larger than that of the lighting fixture 1 using the lens 6 (see Fig. 9).

[0083] (5) Third modification example The light source 42 is not limited to a configuration including a COB type LED chip, and may be, for example, a configuration including a surface mount (SMD: Surface Mount Device) type LED chip. In addition to LEDs, the light source 42 may include organic EL (Organic Electro Luminescence, OEL), or a laser diode.

[0084] The emission surface 62 may be either a configuration in which the entire surface of the emission surface 62 is a plane or a configuration in which a part of the emission surface 62 is a plane. When a part of the emission surface 62 is a plane, it is preferable that the dimple portion 63 is formed only on the plane.

[0085] The Fresnel lens 613 may include at least one annular lens having a sawtooth-shaped cross section.

[0086] In addition, the building material on which the lighting fixture 1 is installed may be other building materials such as wall panels, floor panels, fences, and partitions, in addition to ceiling panels.

[0087] (6) Summary The lens (6, 6A, 6B) of the first aspect according to the above-described embodiment allows the light emitted from the light source (42) of the lighting fixture (1) to pass through. The lens (6, 6A, 6B) includes an incident surface (61) on which light is incident and an exit surface (62) from which light exits. The incident surface (61) has a concave curved surface (611) and a convex curved surface (612) surrounding the concave curved surface (611).

[0088] The above-described lens (6, 6A, 6B) enables both diffusion and high efficiency of the emitted light.

[0089] In the lens (6, 6A, 6B) of the second aspect according to the above-described embodiment, in the first aspect, it is preferable that the boundary portion (614) between the concave curved surface (611) and the convex curved surface (612) is formed of a curved surface that connects the concave curved surface (611) and the convex curved surface (612).

[0090] The above-described lens (6, 6A, 6B) can smoothly connect the light distribution by the concave curved surface (611) and the light distribution by the convex curved surface (612), and can suppress the sense of incongruity in the light distribution.

[0091] In the lens (6, 6A, 6B) of the third aspect according to the above-described embodiment, in the first or second aspect, it is preferable that at least a part of the exit surface (62) is a flat surface.

[0092] The above-described lens (6, 6A, 6B) can easily form the dimple portion (63) on the exit surface (62).

[0093] In the lens (6A) of the fourth aspect according to the above-described embodiment, in the third aspect, it is preferable that the flat surface has a dimple portion (63) with an uneven shape.

[0094] The above-described lens (6A) can suppress the light unevenness and color unevenness of the light emitted from the exit surface (62) by the dimple portion (63).

[0095] In the lens (6, 6A) of the fifth aspect according to the above-described embodiment, in any one of the first to fourth aspects, the convex surface (612) is in an annular shape surrounding the concave surface (611). The top (612a) of the convex surface (612) is preferably formed at a position closer to the outer peripheral edge (612c) of the convex surface (612) than the inner peripheral edge (612b) of the convex surface (612).

[0096] The above-described lens (6, 6A) can increase the degree of diffusion of light distribution by the convex surface (612).

[0097] In the lens (6, 6A, 6B) of the sixth aspect according to the above-described embodiment, in any one of the first to fifth aspects, it is preferable to further include a Fresnel lens (613) surrounding the convex surface (612).

[0098] The above-described lens (6, 6A, 6B) can perform cross light distribution.

[0099] The lighting fixture (1) of the seventh aspect according to the above-described embodiment includes any one of the lenses (6, 6A, 6B) of the first to sixth aspects, a light source (42), and a reflecting member (8) that reflects a part of the light emitted from the emission surface (62).

[0100] The above-described lighting fixture (1) enables both diffusion of the emitted light and high efficiency.

Explanation of Reference Numerals

[0101] 1 Lighting fixture 42 Light source 6, 6A, 6B Lenses 61 Incident surface 611 Concave surface 612 Convex surface 612a Top 612b Inner peripheral edge 612c Outer peripheral edge 613 Fresnel lens 614 Boundary portion 62 Emission surface 63 Dimple portion 8 Auxiliary reflection member (reflection member)

Claims

1. A lens through which light emitted from a light source of a lighting fixture passes, comprising an incident surface on which the light is incident, and an exit surface from which the light exits, wherein the incident surface has a concave curved surface, and a convex curved surface surrounding the concave curved surface, at least a part of the exit surface is a flat surface having a concavo-convex shaped dimple portion, the convex curved surface is an annular shape surrounding the concave curved surface, and the top of the convex curved surface is formed at a position closer to the outer peripheral edge of the convex curved surface than the inner peripheral edge of the convex curved surface Lens.

2. A lens through which light emitted from a light source of a lighting fixture passes, comprising an incident surface on which the light is incident, an exit surface from which the light exits, and a Fresnel lens, wherein the incident surface has a concave curved surface, and a convex curved surface surrounding the concave curved surface, the Fresnel lens includes a plurality of cylindrical lenses having a sawtooth-shaped cross section, arranged concentrically surrounding the convex curved surface, Lens.

3. At least a part of the exit surface is a flat surface The lens according to Claim 2.

4. The flat surface has a concavo-convex shaped dimple portion The lens according to Claim 3.

5. The boundary portion between the concave curved surface and the convex curved surface is composed of a curved surface that connects the concave curved surface and the convex curved surface The lens according to any one of Claims 1 to 4.

6. A lens according to any one of Claims 1 to 5, the light source, and a reflecting member that reflects a part of the light emitted from the exit surface, Lighting fixture.

7. A light source, a lens through which light emitted from the light source passes, and a reflecting member, wherein the lens includes an incident surface on which the light is incident, and an exit surface from which the light exits, the incident surface has a concave curved surface, and a convex curved surface surrounding the concave curved surface, the convex curved surface is an annular shape surrounding the concave curved surface, the top of the convex curved surface is formed at a position closer to the outer peripheral edge of the convex curved surface than the inner peripheral edge of the convex curved surface, and the reflecting member reflects a part of the light emitted from the exit surface Lighting fixture.

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