Lenses and lighting equipment

Abstract

To provide a lens and a lighting fixture capable of improving light extraction efficiency.SOLUTION: A 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 first protrusion section 641 and a second protrusion section 642 respectively protruded in a height direction. An apex 641a of the first protrusion section 641 is positioned lower than an apex 642a of the second protrusion section 642. In the height direction, a second base end 641e of the first protrusion section 641 and a third base end 642d of the second protrusion section 642 are positioned at an intermediary point P1. Given that H1 is a difference in the height direction between the intermediary point P1 and a first base end 641d of the first protrusion section 641 and H2 is a difference in the height direction between the intermediary point P1 and the apex 641a of the first protrusion section 641, the following relation is satisfied: 0.31≤H1 / H2<1.00.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present disclosure relates to lenses and lighting fixtures. [Background technology]

[0002] Patent Document 1 discloses a lens for lighting equipment (conventional lens), which deflects light emitted from a light source of the lighting equipment in a predetermined direction. The conventional lens is symmetrical with respect to the central axis, and has a recessed protrusion formed in the center of the tip of the approximately conical shape.

[0003] Specifically, the conventional lens includes a main body, an outer periphery, and a connecting portion. The main body, the outer periphery, and the connecting portion each have a symmetrical structure with respect to the optical axis. The main body is substantially cylindrical, and the outer periphery is located around the main body. The outer periphery is disposed so as to surround the periphery of the main body with respect to the optical axis, and surrounds the sides of the main body in all directions. In other words, the outer periphery forms an annular prism, and the height of the outer periphery is greater than the height of the main body. The connecting portion connects the main body and the outer periphery. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2020-184488 A Summary of the Invention [Problem to be solved by the invention]

[0005] For lenses through which light emitted from a light source of a lighting fixture passes, there is a demand for improving the light extraction efficiency, which is the ratio of light exiting the lens to light entering the lens. As a result, it is possible to realize energy saving and miniaturization of lighting fixtures equipped with lenses.

[0006] An object of the present disclosure is to provide a lens and a lighting device that can improve the light extraction efficiency. [Means for solving the problem]

[0007] A lens according to an aspect of the present disclosure transmits light emitted from a light source of a lighting device. The lens includes an entrance surface into which the light is incident and an exit surface from which the light is emitted. The entrance surface has a plurality of protrusions formed in a line along a radial direction from a point on the entrance surface toward an outer edge of the entrance surface, and each protruding in a height direction. The plurality of protrusions include a first protrusion and a second protrusion formed adjacent to the first protrusion and closer to the outer edge than the first protrusion. An apex of the first protrusion is lower than an apex of the second protrusion. A base of the first protrusion has a first base end and a second base end opposed to each other in the radial direction, and a base of the second protrusion has a third base end and a fourth base end opposed to each other in the radial direction. The second base end is located closer to the outer edge than the first base end, and the fourth base end is located closer to the outer edge than the third base end. In the height direction, the second base end and the third base end The center is a position between the apex of the first protrusion and the fourth base end. Located in the middle position. The first base end is higher than the intermediate position and lower than the apex of the first protrusion in the height direction, and the fourth base end is lower than the intermediate position in the height direction. If the difference in the height direction between the intermediate position and the position of the first base end is H1, and the difference in the height direction between the intermediate position and the position of the apex of the first protrusion is H2, then 0.31≦H1 / H2<1.00.

[0008] A lighting device according to one aspect of the present disclosure includes the above-described lens, the light source, and a reflecting member that reflects a portion of the light emitted from the exit surface. Effect of the Invention

[0009] As described above, the present disclosure has an effect of improving the light extraction efficiency. [Brief description of the drawings]

[0010] [Figure 1] FIG. 1 is a perspective view showing a lighting fixture including a lens according to an embodiment. [Diagram 2] FIG. 2 is a cross-sectional view showing the above lighting fixture. [Diagram 3]FIG. 3 is an exploded perspective view showing the above lighting fixture. [Figure 4] FIG. 4 is a perspective view showing the lens of the above embodiment. [Diagram 5] FIG. 5 is a cross-sectional view showing the lens. [Figure 6] FIG. 6 is a cross-sectional view showing an optical path in the first comparative example. [Figure 7] FIG. 7 is a cross-sectional view showing an optical path of the lens of the embodiment. [Figure 8] 8A, 8B, and 8C are cross-sectional views of the lens having first protrusions of different heights. [Figure 9] FIG. 9 is a graph showing the light extraction efficiency of the lens under condition I of the same embodiment. [Figure 10] FIG. 10 is a graph showing the light extraction efficiency of the lens under condition II of the above embodiment. [Figure 11] FIG. 11 is a cross-sectional view illustrating the light extraction efficiency of the lens under the above condition II. [Figure 12] FIG. 12 is a cross-sectional view showing a part of the lighting fixture of the first modified example. [Figure 13] FIG. 13 is a graph showing the light extraction efficiency of the lens under condition I of the same embodiment. [Figure 14] FIG. 14 is a perspective view showing a lens of the second modified example. [Figure 15] FIG. 15 is a cross-sectional view showing the lens. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] The following embodiments generally relate to a lens and a lighting device, and more particularly, to a lens and a lighting device that can improve light extraction efficiency.

[0012] The lens and lighting device according to the embodiment will be described in detail below with reference to Figs. 1 to 11. However, each figure described in the following embodiment is a schematic diagram, and the size and thickness ratio of each component do not necessarily reflect the actual dimensional ratio. Note that the configuration described in the following embodiment is merely one example of the present disclosure. The present disclosure is not limited to the following embodiment, and various modifications are possible depending on the design, etc., as long as the effects of the present disclosure can be achieved.

[0013] In the following description, unless otherwise specified, an X-axis, a Y-axis, and a Z-axis that are orthogonal to each other are defined in FIG. 1. For convenience, one of the two directions along the X-axis is defined as the rightward direction, and the other as the leftward direction. One of the two directions along the Y-axis is defined as the forward direction, and the other as the backward direction. One of the two directions along the Z-axis is defined as the upward direction, and the other as the downward direction. Note that these directions do not limit the directions when the lens and the lighting device are actually used.

[0014] (Embodiment) (1) Lighting equipment The configuration of a lighting device 1 according to an embodiment will be described with reference to the drawings.

[0015] The lighting fixture 1 is installed, for example, in a store, an office, a theater, a commercial facility, a hall, a house, etc. The lighting fixture 1 is, for example, a recessed downlight, and is embedded in a building material such as a ceiling panel to illuminate the area below.

[0016] 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 reflecting member 5, a lens 6, a frame 7, and an auxiliary reflecting member 8.

[0017] (1.1) The Foundation The base 2 includes a cylindrical body 21, the upper end of which is closed by an upper wall 211. The lower end of the cylindrical body 21 is open, and the 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 inserted into the three insertion holes 213, respectively. The lower ends of the three screws are screwed into the screw holes 731 (see FIG. 3) of the frame 7, respectively, whereby the light source holder 3, the light source unit 4, the main reflection member 5, and the frame 7 are attached to the base 2.

[0018] 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 comes into contact with the protrusion 212. That is, the base 2 functions as a heat dissipation member that dissipates heat generated by the light source 42 mounted on the LED substrate 41 to the surroundings, and is preferably formed of a metal with high thermal conductivity such as aluminum, copper, or iron. The cylinder 21 and the heat dissipation fins 22 may be integrally molded by aluminum die casting or the like, or may be integrally formed by bonding the separate cylinder 21 and the heat dissipation fins 22. The base 2 may not be provided with the heat dissipation fins 22.

[0019] (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 extending upward and downward from the periphery of the holder body 31. An upwardly recessed recess 311 is formed in 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 in the square bottom surface of the recess 311.

[0020] 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 contact the lower surface of the upper wall 211 of the cylindrical body 21 .

[0021] The LED board 41 of the light source unit 4 is housed in the recess 311 of the light source holder 3, and the protrusion 212 of the base 2 is inserted through the opening 312 from above and comes into surface contact with the upper surface of the LED board 41.

[0022] (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 .

[0023] The LED substrate 41 and the light source 42 constitute a COB (Chip On Board) type LED (Light Emitting Diode) chip.

[0024] The LED substrate 41 has a square plate shape, and is, for example, a ceramic substrate, a resin substrate, a metal-based substrate, etc. On the LED substrate 41, a light source 42 and a pair of electrodes 43 are mounted.

[0025] The light source 42 includes a plurality of LED chips, which are mounted in a circular shape on the lower surface of the LED substrate 41 and 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. The light source 42 may include one LED chip. The sealing member is, for example, made of a translucent resin and includes a phosphor. The phosphor has a function of converting the wavelength of light from the LED chip. The sealing member is, for example, a silicone resin that includes phosphor particles. If the LED chip emits blue light and the phosphor particles are a YAG-based yellow phosphor, 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 shape for each row, or may seal each of the plurality of LED chips individually.

[0026] The pair of electrodes 43 are made of a highly conductive material such as copper or aluminum, and are mounted on the LED substrate 41. An electric wire or conductor that serves as a supply path for DC power from the outside 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 illuminated by the DC power.

[0027] The LED board 41 may also be equipped with a power supply circuit that converts external AC power into DC power. In this case, an electric wire or conductor that serves as a supply path for AC power from the outside is connected to the pair of electrodes 43. The light source 42 is illuminated by the DC power output by the power supply circuit.

[0028] The LED board 41 of the light source unit 4 is stored in the recess 311 of the light source holder 3 with the light source 42 facing downward, and the upper surface of the LED board 41 is in surface contact with the protrusion 212 of the base 2 inserted from above through the opening 312 of the light source holder 3. Therefore, 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, etc.

[0029] (1.4) Reflective material The main reflection member 5 includes a cylindrical body 51 whose axial direction is the up-down direction along the Z axis, and an annular flange portion 52 provided on the outer peripheral surface of the body 51. The main reflection member 5 is formed of, for example, a white resin material. The resin material constituting the main reflection member 5 is preferably polybutylene terephthalate or the like. The main reflection member 5 may be formed of a metal material such as aluminum, or may be a resin molded product having a metal film such as aluminum formed on the inner surface thereof.

[0030] The cylinder 51 integrally includes a cylindrical upper cylinder portion 511 and a cylindrical lower cylinder portion 512, and has a two-stage structure in which the diameter of the lower cylinder portion 512 is larger than the diameter of the upper cylinder portion 511. The upper cylinder portion 511 is located below the light source 42 of the light source unit 4, and the light source 42 is located at the top (or near the upper end) of the upper cylinder portion 511. The inner surfaces of the upper cylinder portion 511 and the lower cylinder portion 512 are light reflecting surfaces, and the light emitted downward by the light source 42 passes through the inside of the upper cylinder portion 511, then passes through the inside of the lower cylinder portion 512, and enters the lens 6. A part of the light passing through the inside of the upper cylinder portion 511 is reflected by the inner surface of the upper cylinder portion 511. A part of the light passing through the inside of the lower cylinder portion 512 is reflected by the inner surface of the lower cylinder portion 512.

[0031] The flange 52 includes an annular portion 521 and a side wall 522. The annular portion 521 is an annular shape extending outward from the upper end of the lower tube portion 512 on the outer circumferential surface of the lower tube portion 512. The side wall 522 is an annular wall extending upward from the outer circumferential edge of the annular portion 521. In addition, three locking portions 523 are formed on the lower surface of the annular portion 521 at equal intervals in the circumferential direction. The locking portions 523 are composed of a pair of locking claws extending downward from the lower surface of the annular portion 521. The locking portions 523 are locked to the locking projections 65 of the lens 6, whereby the lens 6 is attached to the lower end of the main reflecting member 5.

[0032] (1.5) Lenses Lens 6 is a light-transmitting member having light-transmitting properties, and is housed in lower cylinder portion 512 so as to cover the lower end opening of lower cylinder portion 512 of main reflecting member 5. Lens 6 transmits light that has traveled from light source 42 through the inside of main reflecting member 5 and reached lens 6.

[0033] 4 and 5, the lens 6 includes a disk-shaped lens body 60. The upper surface of the lens body 60 constitutes an incident surface 61 onto which light from the light source 42 is incident. The lower surface of the lens body 60 constitutes an exit surface 62 through which light that has passed through the lens 6 is emitted to the outside of the lens 6.

[0034] The incident surface 61 has a flat surface 63 and a Fresnel surface 64. The flat surface 63 has a circular shape formed concentrically with the circular incident surface 61. The Fresnel surface 64 has an annular shape surrounding the flat surface 63.

[0035] Specifically, the Fresnel lens 64 includes a first protrusion 641 having an annular shape surrounding the plane 63, and a second protrusion 642 having an annular shape surrounding the first protrusion 641. The first protrusion 641 is formed along the outer periphery of the plane 63, and the second protrusion 642 is formed outside the first protrusion 641 so as to surround the first protrusion 641. That is, on the incident surface 61, the first protrusion 641 having an annular shape surrounds the circular plane 63, and the second protrusion 642 having an annular shape surrounds the first protrusion 641.

[0036] The above-mentioned lens 6 functions as a wide-angle lens. Specifically, the lens 6 has a flat surface 63 surrounded by the first protrusion 641 on the entrance surface 61, and the exit surface 62 has a flat shape. Therefore, the lens 6 functions as a wide-angle lens by the flat surface 63 of the entrance surface 61 and the exit surface 62. In addition, if the outer edge of the entrance surface 61 is the outer periphery 611, the lens 6 can suppress the light distribution range of the light incident on the outer periphery side of the lens 6 by the Fresnel 64 formed along the outer periphery 611.

[0037] The lens 6 is made of a light-transmitting material having light-transmitting properties, and is formed of, for example, a transparent resin material such as acrylic, a silicone-based resin material, or polycarbonate, or a glass material.

[0038] In addition, three locking projections 65 are formed at equal intervals in the circumferential direction on the outer circumferential end of the lens body 60. The locking portions 523 of the main reflecting member 5 are locked to the locking projections 65, whereby the lens 6 is attached to the lower end of the main reflecting member 5.

[0039] The lens 6 will be described in detail later.

[0040] (1.6) Frame The frame 7 is formed into a cylindrical shape from resin or the like, and includes a tube 71, a flange 72, and three mounting pieces 73 (only one mounting piece 73 is shown in FIG. 3). The tube 71 is cylindrical in shape with its axial direction extending up and down along the Z axis, and a circular upper opening 711 is formed on the top surface of the tube 71, and a circular lower opening 712 is formed on the bottom surface of the tube 71. The lower tube portion 512 of the main reflection member 5 is inserted through the upper opening 711 from above, and the lower tube portion 512 is housed in the tube 71.

[0041] The flange 72 is formed in a circular ring shape at the lower end of the cylindrical body 71 , and extends from the edge of the lower opening 712 towards the outside of the cylindrical body 71 .

[0042] The three mounting pieces 73 are formed at the upper end of the cylindrical body 71 at equal intervals in the circumferential direction of the upper opening 711 .

[0043] Furthermore, the mounting 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 from above into the three insertion holes 213 (see FIG. 1) of the base 2 are screwed into the screw holes 731, respectively, thereby attaching the light source holder 3, the light source unit 4, the main reflection member 5, and the frame 7 to the base 2. In other words, the light source holder 3, the light source unit 4, and the main reflection member 5 are sandwiched between the base 2 and the frame 7.

[0044] (1.7) Auxiliary reflective member The auxiliary reflecting member 8 corresponds to the reflecting member of the present disclosure, and is attached inside the frame 7. The auxiliary reflecting member 8 includes a cylindrical body 81 and three flexible pieces 82.

[0045] The cylinder 81 has a cylindrical shape, and a circular opening formed at the upper end of the cylinder 81 is an entrance 811, and a circular opening formed on the lower surface of the cylinder 81 is an exit 812. The diameter of the cylinder 81 gradually increases from the upper end to the lower end of the cylinder 81. That is, the diameter of the exit 812 is larger than the diameter of the entrance 811. The upper end of the cylinder 81 supports the periphery of the exit surface 62 of the lens 6, and the lower end of the lower cylinder portion 512 of the main reflecting member 5 abuts against the entrance surface 61, so that the lens 6 is sandwiched between the main reflecting member 5 and the auxiliary reflecting member 8.

[0046] Three flexible pieces 82 are formed at equal intervals along the periphery of the entrance 811 at the upper end of the cylindrical body 81. The flexible pieces 82 extend upward from the periphery of the entrance 811, and locking pieces 821 extend outward from the upper ends of the flexible pieces 82.

[0047] The auxiliary reflective member 8 is stored inside the frame 7 so that the axial direction of the cylinder 81 is aligned vertically. The upper end of the auxiliary reflective member 8 is inserted into the frame 7 from the lower opening 712 of the frame 7. When the auxiliary reflective member 8 is inserted into the frame 7, the bending piece 82 bends and passes through the upper opening 711 from below, and the lower surface of the locking piece 821 locks onto the upper surface of the mounting piece 73. In other words, the auxiliary reflective member 8 is attached to the frame 7.

[0048] The inner surface of the cylinder 81 constitutes a reflective surface 813 that reflects light. The auxiliary reflective member 8 having the reflective 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. The auxiliary reflective member 8 may also be a resin cylinder with a metal film such as aluminum vapor-deposited on its surface. The resin material constituting the auxiliary reflective member 8 is polybutylene terephthalate or the like.

[0049] (1.8) Illumination In the lighting device 1 configured as described above, the light emitted by the light source 42 passes through the inside of the cylindrical body 51 of the main reflecting member 5 and enters the entrance surface 61 of the lens 6. The light that enters the entrance surface 61 passes through the inside of the lens 6 and exits from the exit surface 62 of the lens 6. The exit surface 62 is a plane parallel to the XY plane (a plane defined by the X-axis and the Y-axis in FIG. 1). The light that exits from the exit surface 62 enters the inside of the cylindrical body 81 from 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 passes through the main reflecting member 5 and the lens 6 and reaches the inside of the cylindrical body 81. Of the light that reaches the inside of the cylindrical body 81, the light that is reflected at least once by the reflecting surface 813 is defined as reflected light. Of the light that reaches the inside of the cylindrical body 81, the light that is not reflected even once by the reflecting surface 813 is defined as direct light. Illumination light including reflected light and direct light is output from the emission port 812 toward the illumination space below the lighting device 1. That is, the lighting device 1 emits illumination light from the emission port 812.

[0050] (2) Lens details The lens 6 controls the light distribution of the light emitted by the light source 42 of the lighting device 1, and emits illumination light with a wide beam angle from the emission port 812. For the lens 6 used in such a lighting device 1, an improvement in the light extraction efficiency (the ratio of light exiting the lens 6 to light entering the lens 6) is required. In particular, it is important to improve the light extraction efficiency of the Fresnel lens 64.

[0051] For example, a lens using Fresnel is lens 6R of the following comparative example. Note that the comparative example is different from this embodiment.

[0052] (2.1) Comparative Example Fig. 6 shows the optical path of a lighting device of a comparative example that uses a lens 6R different from the lens 6 of the present embodiment. Note that Fig. 6 only illustrates a light source 42 and the lens 6R. The same components of the lens 6R as those of the lens 6 are denoted by the same reference numerals as those of the lens 6.

[0053] The lens 6R includes a disk-shaped lens body 60R. An upper surface of the lens body 60R constitutes an incident surface 61R on which light from the light source 42 is incident. A lower surface of the lens body 60R constitutes an exit surface 62R through which light that has passed through the lens 6R is emitted to the outside of the lens 6R.

[0054] The incident surface 61R has a plane 63R and a Fresnel 64R. The plane 63R is a circular shape formed concentrically with the circular incident surface 61R. The Fresnel 64R is annular surrounding the plane 63R. Specifically, the Fresnel 64R includes an annular protrusion 649 surrounding the plane 63R. The protrusion 649 is an annular lens having a sawtooth cross section, and is formed along the outer periphery of the plane 63R. That is, the Fresnel 64R is a single Fresnel, and on the incident surface 61R, one annular protrusion 649 surrounds the circular plane 63R.

[0055] 6, light emitted from the center of light source 42 and incident on inner surface 649a of protrusion 649 is defined as L101. Of light L101, light L102 that is incident on an upper portion of inner surface 649a is reflected by outer surface 649b of protrusion 649. Light L102 reflected by outer surface 649b is emitted from emission surface 62R.

[0056] On the other hand, the light L103 of the light L101 that is incident on the lower part of the inner surface 649a (near the base end of the protrusion 649) passes through the inside of the protrusion 649 without hitting the outer surface 649b, is reflected by the exit surface 62R, and is repeatedly reflected inside the lens body 60R. Then, the light L103 is emitted from the side end 69R of the lens body 60R, not from the exit surface 62R of the lens body 60R. That is, in the lens 6R, the light L103 that is not emitted from the exit surface 62R is generated by the protrusion 649. In this way, the lens 6R has the protrusion 649 for light distribution control, but it is difficult to control the light distribution of the light L103 that is incident on the base end of the protrusion 649, and optical loss is likely to occur. Therefore, in the lens 6R, the light L103 that is not emitted from the exit surface 62R becomes a loss, and the light extraction efficiency is deteriorated. The light extraction efficiency of the lens 6R is the ratio of light L102 emitted from the lens 6R to light L101 incident on the lens 6R.

[0057] (2.2) Lens of the embodiment In the above-described comparative example, the light L103 generated by the protrusion 649 becomes a loss, which is a factor in deteriorating the light extraction efficiency.

[0058] Therefore, the lighting device 1 of this embodiment includes a lens 6 shown in FIGS.

[0059] The lens 6 includes a disk-shaped lens body 60 , the upper surface of which is an entrance surface 61 , and the lower surface of which is an exit surface 62 .

[0060] The entrance surface 61 has a plane 63 and a Fresnel 64. The plane 63 is circular and formed concentrically with the circular entrance surface 61. The Fresnel 64 is annular and surrounds the plane 63. If a virtual axis Za1 passing through the center of the circular exit surface 62 and extending vertically along the Z axis is taken as Za1, the lens 6 is formed in a shape that is symmetrical with respect to the virtual axis Za1.

[0061] Specifically, the Fresnel 64 includes a first protrusion 641 in the shape of an annular ring surrounding the plane 63, and a second protrusion 642 in the shape of an annular ring surrounding the first protrusion 641. The first protrusion 641 is a lens in the shape of an annular ring having a sawtooth cross section, and protrudes upward along the outer periphery of the plane 63. The second protrusion 642 is a lens in the shape of an annular ring having a sawtooth cross section, and protrudes upward outside the first protrusion 641 so as to surround the first protrusion 641. That is, the Fresnel 64 is a double Fresnel, and on the entrance surface 61, the first protrusion 641 in the shape of an annular ring surrounds the circular plane 63, and the second protrusion 642 in the shape of an annular ring surrounds the first protrusion 641, and the first protrusion 641 and the second protrusion 642 are arranged coaxially with respect to the circular plane 63.

[0062] In other words, the incident surface 61 has a first protrusion 641 and a second protrusion 642 formed side by side along a radial direction from the center (one point) of the incident surface 61 toward an outer circumferential edge 611 of the incident surface 61. The first protrusion 641 and the second protrusion 642 each protrude upward (in the height direction along the Z axis), and the second protrusion 642 is formed adjacent to the first protrusion 641 and closer to the outer circumferential edge 611 of the incident surface 61 than the first protrusion 641.

[0063] The first protrusion 641 includes an apex 641a, an inner surface 641b, an outer surface 641c, a first base end 641d, and a second base end 641e. The apex 641a is the upper end of the annular shape of the first protrusion 641. The inner surface 641b is an annular inclined surface extending obliquely from the apex 641a toward the plane 63. The outer surface 641c is an annular inclined surface extending obliquely from the apex 641a toward a third base end 642d of the second protrusion 642. The first base end 641d is the lower end of the annular shape of the inner surface 641b. The second base end 641e is the lower end of the annular shape of the outer surface 641c.

[0064] The second protrusion 642 includes an apex 642a, an inner surface 642b, an outer surface 642c, a third base end 642d, and a fourth base end 642e. The apex 642a is the upper end of the second protrusion 642. The inner surface 642b is an annular inclined surface extending obliquely from the apex 642a toward the second base end 641e of the first protrusion 641. The outer surface 642c is an annular inclined surface extending obliquely from the apex 642a toward the outer peripheral edge 611. The third base end 642d is the lower end of the annular shape of the inner surface 642b. The fourth base end 642e is the lower end of the annular shape of the outer surface 642c.

[0065] The second base end 641e of the first protrusion 641 and the third base end 642d of the second protrusion 642 are in the same position. If the direction along the Z axis is the height direction, the height position of the second base end 641e and the height position of the third base end 642d are at the same intermediate position P1 (see FIG. 5).

[0066] If the direction along the Z axis is the height direction, then the apex 641a of the first protrusion 641 is lower than the apex 642a of the second protrusion 642.

[0067] The base (lower end) of the first protrusion 641 has a first base end 641d and a second base end 641e that face each other in a radial direction from the center (one point) of the incident surface 61 toward the outer circumferential edge 611 of the incident surface 61, and the base (lower end) of the second protrusion 642 has a third base end 642d and a fourth base end 642e that face each other in a radial direction. The second base end 641e is located closer to the outer circumferential edge 611 than the first base end 641d, and the fourth base end 642e is located closer to the outer circumferential edge 611 than the third base end 642d. In the height direction, the second base end 641e and the third base end 642d are located at the same intermediate position P1 (see FIG. 5).

[0068] 5, the difference in height between the intermediate position P1 and the position of the first base end 641d in the height direction is defined as a first height difference H1. The difference in height between the intermediate position P1 and the position of the apex 641a of the first protrusion 641 in the height direction is defined as a second height difference H2. The difference in height between the intermediate position P1 and the position of the apex 642a of the second protrusion 642 in the height direction is defined as a third height difference H3.

[0069] In the lens 6 configured as described above, the relationships between the first height difference H1, the second height difference H2, and the third height difference H3 are set as the following [Condition I] and [Condition II]. [Condition I]0.31≦H1 / H2<1.00 [Condition II] 0.34≦H2 / H3≦0.61

[0070] Fig. 7 shows the optical path of the lens 6 that satisfies [Condition I] and [Condition II]. Note that Fig. 7 shows only the light source 42 and the lens 6.

[0071] As shown in FIG. 7, light L 1 emitted from the center of the light source 42 travels toward the Fresnel lens 64 .

[0072] Of the light L1, light L2 traveling from the light source 42 toward the lower part of the second protrusion 642 is blocked by the first protrusion 641, hits the first protrusion 641, and is incident on an inner surface 641b of the first protrusion 641. The light L2 incident on the inner surface 641b is reflected by an outer surface 641c of the first protrusion 641. The light L2 reflected by the outer surface 641c is emitted from the exit surface 62.

[0073] Of the light L1, light L3 traveling from the light source 42 toward the upper part of the second protrusion 642 is incident on the inner surface 642b of the second protrusion 642 without hitting the first protrusion 641. The light L3 incident on the inner surface 642b is reflected by the outer surface 642c of the second protrusion 642. The light L3 reflected by the outer surface 642c is emitted from the emission surface 62.

[0074] In this way, in the lens 6, both the light L2 traveling from the light source 42 toward the lower part of the second protrusion 642 and the light L3 traveling from the light source 42 toward the upper part of the second protrusion 642 are emitted from the emission surface 62. Therefore, the light extraction efficiency of the lens 6 is the ratio of the light L2, L3 emitted from the lens 6 to the light L1 incident on the lens 6, and is higher than the light extraction efficiency of the lens 6R of the above-mentioned comparative example. In other words, the lens 6 can improve the light extraction efficiency.

[0075] [Condition I] and [Condition II] are explained in detail below.

[0076] (2.2.1) Condition I In the lens 6, the relationship between the first height difference H1 and the second height difference H2 is set as follows [Condition I]. [Condition I]0.31≦H1 / H2<1.00

[0077] 8A, 8B, and 8C show three lenses 6 each having a different height of the first protrusion 641. In the following description, the lens 6 in FIG. 8A will be referred to as lens 6(1), the lens 6 in FIG. 8B as lens 6(2), and the lens 6 in FIG. 8C as lens 6(3).

[0078] The height dimension of the first protrusion 641 of the lens 6(1) is the largest, the height dimension of the first protrusion 641 of the lens 6(2) is the second largest, and the height dimension of the first protrusion 641 of the lens 6(3) is the smallest. Specifically, H2 / H3 of the lens 6(1) is 0.66, H2 / H3 of the lens 6(2) is 0.56, and H2 / H3 of the lens 6(3) is 0.4. The larger H2 / H3 is, the larger the height dimension of the first protrusion 641 is. It can also be said that the first protrusion 641 of the lens 6(1) is the largest, the first protrusion 641 of the lens 6(2) is the second largest, and the first protrusion 641 of the lens 6(3) is the smallest.

[0079] Fig. 9 shows the change in light extraction efficiency ηa of each of lens 6(1), lens 6(2), and lens 6(3) versus H1 / H2. In Fig. 9, curve W1 shows the light extraction efficiency ηa of lens 6(1), curve W2 shows the light extraction efficiency ηa of lens 6(2), and curve W3 shows the light extraction efficiency ηa of lens 6(3).

[0080] In the region where H1 / H2 is relatively large, the light extraction efficiency ηa is higher as the height dimension of the first protrusion 641 is larger (H2 / H3 is larger). In each of the curves W1-W3, when H1 / H2 is gradually decreased from 1, the light extraction efficiency ηa maintains a substantially constant value (about 74 to 75%) until H1 / H2 decreases to about 0.31. However, when H1 / H2 decreases to about 0.31, the light extraction efficiency ηa starts to decrease. When H1 / H2 further decreases from 0.31, the light extraction efficiency ηa also decreases with the decrease in H1 / H2. Therefore, in this embodiment, the lower limit K1 of H1 / H2 is set to "0.31", which is the change point at which the light extraction efficiency ηa starts to decrease.

[0081] In this embodiment, H1 / H2 is set to less than "1.00" (=K2) so that the position of the apex 641a of the first protrusion 641 is higher than the position of the plane 63 in the height direction.

[0082] Therefore, by satisfying [Condition I] 0.31≦H1 / H2<1.00, the lens 6 can improve the light extraction efficiency.

[0083] (2.2.2) Condition II In the lens 6, the relationship between the second height difference H2 and the third height difference H3 is set as follows [Condition II]. [Condition II] 0.34≦H2 / H3≦0.61

[0084] If the lens 6 in Fig. 11 is the lens 6(4), Fig. 10 shows the change in the light extraction efficiency ηb of the lens 6(4) relative to H2 / H3. In Fig. 10, the curve W11 shows the light extraction efficiency ηb of the lens 6(4).

[0085] The light extraction efficiency ηb reaches a peak value η1 (≈75%) when H2 / H3 is around 0.60. The light extraction efficiency ηb decreases from the peak value η1 whether H2 / H3 decreases from around 0.60 or increases from around 0.60.

[0086] Therefore, in this embodiment, the lower limit K11 of H2 / H3 is set to "0.34" when H2 / H3 decreases from around 0.60 and the light extraction efficiency ηb decreases by 2% from the peak value η1.

[0087] Moreover, the upper limit K12 of H2 / H3 is determined by the amount of light that is incident on the second protrusion 642 and is light distribution controlled by the second protrusion 642. Specifically, a description will be given using the lens 6(4) in FIG. 11. First, the light L11 emitted from the center of the light source 42 includes the light L13 that is incident on the inner surface 641b of the first protrusion 641 and the light L12 that is incident on the inner surface 642b of the second protrusion 642. When the value of H2 / H3 increases, the light L13 increases and the light L12 decreases. That is, when the value of H2 / H3 increases, the amount of the light L12 that is light distribution controlled by the second protrusion 642 decreases, and the light distribution by the lens 6(4) is disturbed. Therefore, since the value of H2 / H3 that can sufficiently secure the amount of the light L12 that is light distribution controlled by the second protrusion 642 is 0.61 or less, "0.61" is set as the upper limit K12 of H2 / H3.

[0088] Therefore, by satisfying [Condition II] 0.34≦H2 / H3≦0.61, the lens 6 can improve the accuracy of light distribution control.

[0089] The above-mentioned lens 6 functions as a wide-angle lens. Specifically, the lens 6 has a flat surface 63 surrounded by a first protrusion 641 on the entrance surface 61, and the exit surface 62 has a flat shape. Therefore, the lens 6 functions as a wide-angle lens by the flat surface 63 of the entrance surface 61 and the exit surface 62. In addition, the lens 6 can restrict the light distribution range of the light incident on the outer periphery side of the lens 6 by the Fresnel 64 formed along the outer periphery 611 of the entrance surface 61.

[0090] (3) First Modification If the lighting fixture 1 is a downlight, it is preferable that the light-shielding angle θ1 of the auxiliary reflecting member 8 is 30 degrees or less, as shown in Fig. 12. Note that Fig. 12 shows only the lens 6 and the cylindrical body 81 of the auxiliary reflecting member 8.

[0091] The shading angle θ1 is an angle with respect to the exit surface 62 of the lens 6, and is the angle at which the exit surface 62 of the lens 6 is blocked by the cylindrical body 81 of the auxiliary reflecting member 8 and becomes invisible. In other words, when a person looks up at the lighting device 1, if the angle of the person's line of sight is greater than the shading angle θ1, the person can see the exit surface 62 and sees the light from the exit surface 62 directly, which causes glare. Also, when a person looks up at the lighting device 1, if the angle of the person's line of sight is equal to or less than the shading angle θ1, the person cannot see the exit surface 62 and does not see the light from the exit surface 62 directly.

[0092] Therefore, by setting the shading angle θ1 to 30 degrees or less, it is possible to reduce the glare felt when looking up at the lighting fixture 1 and to widen the illumination range of the light emitted by the lighting fixture 1.

[0093] In the first modified example, the following [Condition IA] is used instead of the above-mentioned [Condition I]. [Condition IA] 0.31≦H1 / H2<0.88

[0094] 13 shows the change in the light extraction efficiency ηc of the lens 6 relative to H1 / H2. In the first modified example, similar to [Condition I], the lower limit K21 of H1 / H2 is set to "0.31", which is the change point at which the light extraction efficiency ηc begins to decrease.

[0095] In the first modified example, the value of H1 / H2 when the light extraction efficiency ηc drops by 2% from the peak value η2 is set to "0.88" as the upper limit K22 of H1 / H2.

[0096] Therefore, by making the lens 6 satisfy [Condition IA] 0.31≦H1 / H2<0.88, it is possible to further improve the light extraction efficiency in the first modified example.

[0097] (4) Second Modification 14 and 15 show a lens 6A of a second modified example. The entrance surface 61 of the lens 6A has a convex curved surface 66 surrounded by a circular ring-shaped first protrusion 641. The convex curved surface 66 is formed in a shape that is symmetrical with respect to a virtual axis Za1. That is, the lens 6A is a lens in which the flat surface 63 of the lens 6 is changed to the convex curved surface 66.

[0098] Lens 6A, by virtue of convex curved surface 66 formed by recessing incident surface 61, is able to condense light emerging from exit surface 62 more effectively than lens 6 of the above-described embodiment.

[0099] Moreover, the Fresnel lens 64 having the first protrusion 641 and the second protrusion 642 can improve the light extraction efficiency in the same way as the lens 6.

[0100] (5) Third Modification The Fresnel lens 64 may have three or more annular projections. In this case, the three or more projections include a first projection 641 and a second projection 642.

[0101] The entrance surface 61 may have a concave surface surrounded by annular first protrusion 641, instead of the above-mentioned flat surface 63 and convex surface 66. In this case, the light exiting from the exit surface 62 can be diffused more than in the lens 6 of the above-mentioned embodiment.

[0102] The light source 42 is not limited to a configuration including a COB type LED chip, and may be a configuration including, for example, a surface mount device (SMD) type LED chip. The light source 42 may include an organic electroluminescence (OEL) or a laser diode other than an LED.

[0103] The emission surface 62 may be configured such that the entire surface of the emission surface 62 is flat, or such that only a portion of the emission surface 62 is flat. The flat surface formed on the emission surface 62 may have dimples formed thereon that are uneven.

[0104] Furthermore, the construction material on which the lighting fixture 1 is installed is not limited to a ceiling panel, and may be other construction materials such as a wall panel, a floor panel, a fence, and a partition.

[0105] (6) Summary The lens (6, 6A) of the first aspect according to the above-described embodiment transmits light emitted from the light source (42) of the lighting device (1). The lens (6, 6A) includes an entrance surface (61) through which the light is incident and an exit surface (62) through which the light is exited. The entrance surface (61) has a plurality of protrusions (641, 642) formed in a line along a radial direction from one point on the entrance surface (61) toward an outer edge (611) of the entrance surface (61) and protruding in a height direction. The plurality of protrusions include a first protrusion (641) and a second protrusion (642) formed adjacent to the first protrusion (641) and closer to the outer edge (611) than the first protrusion (641). The apex (641a) of the first protrusion (641) is lower than the apex (642a) of the second protrusion (642). The base of the first protrusion (641) has a first base end (641d) and a second base end (641e) that face each other in the radial direction. The base of the second protrusion (642) has a third base end (642d) and a fourth base end (642e) that face each other in the radial direction. The second base end (641e) is located closer to the outer edge (611) than the first base end (641d), and the fourth base end (642e) is located closer to the outer edge (611) than the third base end (642d). In the height direction, the second base end (641e) and the third base end (642d) are located at an intermediate position (P1). If the difference in height between the intermediate position (P1) and the position of the first base end (641d) in the height direction is H1, and the difference in height between the intermediate position (P1) and the position of the apex (641a) of the first protrusion (641) in the height direction is H2, then 0.31≦H1 / H2<1.00.

[0106] The above-mentioned lenses (6, 6A) can improve the light extraction efficiency.

[0107] In the second aspect of the lens (6, 6A) according to the above-mentioned embodiment, in the first aspect, if the difference in height between the intermediate position (P1) and the position of the apex (642a) of the second protrusion (642) is H3, it is preferable that 0.34≦H2 / H3≦0.61.

[0108] The above-mentioned lenses (6, 6A) can improve the accuracy of light distribution control.

[0109] In the lens (6) of the third aspect according to the above-mentioned embodiment, in the first or second aspect, it is preferable that at least a part of the exit surface (62) is flat. Each of the multiple protrusions (641, 642) is annular. The entrance surface (61) has a flat surface (63) surrounded by the protrusion (641) that is the furthest from the outer edge (611) among the multiple protrusions (641, 642).

[0110] The above-mentioned lens (6) can ensure the beam angle of the emitted light.

[0111] In the lens (6A) of the fourth aspect according to the above embodiment, in the first or second aspect, it is preferable that at least a part of the exit surface (62) has a planar shape. Each of the multiple protrusions (641, 642) is annular. The entrance surface (61) has a curved surface (66) surrounded by the protrusion (641) that is the furthest from the outer edge (611) among the multiple protrusions (641, 642). The curved surface (66) has an axisymmetric shape with respect to a virtual axis (Za1) perpendicular to the exit surface (62).

[0112] The above-mentioned lens (6A) can control the light distribution range to a desired range.

[0113] In the lens (6A) of the fifth aspect according to the above-mentioned embodiment, in the fourth aspect, the curved surface is preferably a convex curved surface (66).

[0114] The lens (6A) described above can focus the light emitted from the emission surface (62).

[0115] In the lens (6, 6A) of the sixth aspect according to the above-mentioned embodiment, in any one of the first to fifth aspects, the plurality of protrusions (641, 642) preferably constitute a Fresnel lens (64).

[0116] The above-mentioned lenses (6, 6A) can suppress the light distribution range.

[0117] A lighting device (1) of a seventh aspect according to the above-described embodiment includes a lens (6, 6A) of any one of the first to sixth aspects, a light source (42), and a reflecting member (8) that reflects a portion of the light emitted from the exit surface (62).

[0118] The above-mentioned lighting fixture (1) can improve the light extraction efficiency.

[0119] In the lighting device (1) of the eighth aspect according to the above-mentioned embodiment, in the seventh aspect, it is preferable that the light blocking angle (θ1) of the reflecting member (8) is 30 degrees or less.

[0120] The above-mentioned lighting fixture (1) can provide a light irradiation range that is generally appropriate for a downlight.

[0121] In the ninth aspect of the lighting device (1) according to the above embodiment, in the eighth aspect, it is preferable that 0.31≦H1 / H2≦0.88.

[0122] The above-mentioned lighting fixture (1) can further improve the light extraction efficiency. [Explanation of symbols]

[0123] 1 Lighting equipment 42 Light source 6, 6A Lenses 61 Entrance plane 611 Outer rim 62 Exit surface 63 plane 64 Fresnel 641 First protrusion (protrusion) 641a Vertex 641d First base end 641e 2nd proximal end 642 Second protrusion (protrusion) 642a Vertex 642d 3rd proximal end 642e 4th proximal end 66 Convex curved surface (curved surface) 8 Auxiliary reflective member (reflective member) P1 intermediate position H1 1st height difference H2 2nd height difference H3 3rd height difference θ1 Shading angle Za1 Virtual axis

Claims

1. A lens through which light emitted from a light source of a lighting fixture passes, an incidence surface on which the light is incident; an exit surface from which the light exits, The entrance surface has a plurality of protrusions formed along a radial direction from a point on the entrance surface toward an outer edge of the entrance surface and protruding in a height direction, the plurality of protrusions include a first protrusion and a second protrusion formed adjacent to the first protrusion and closer to the outer edge than the first protrusion, The apex of the first protrusion is lower than the apex of the second protrusion, The base portion of the first protrusion has a first base end and a second base end opposed to each other in the radial direction, the base portion of the second protrusion has a third base end and a fourth base end opposed to each other in the radial direction, the second base end is located closer to the outer edge than the first base end; the fourth base end is located closer to the outer edge than the third base end; In the height direction, the second base end and the third base end are located at intermediate positions between the apex of the first protrusion and the fourth base end, In the height direction, the first base end is higher than the intermediate position and lower than the apex of the first protrusion, The fourth base end is lower than the intermediate position in the height direction, Let H1 be the difference between the intermediate position and the position of the first base end in the height direction, and H2 be the difference between the intermediate position and the position of the apex of the first protrusion in the height direction. 0.31≦H1 / H2<1.00 It becomes lens.

2. If the difference between the intermediate position and the apex position of the second protrusion in the height direction is H3, 0.34≦H2 / H3≦0.61 It becomes The lens of claim 1.

3. At least a portion of the exit surface is planar, Each of the plurality of protrusions is annular, The entrance surface has a plane surrounded by the protrusion that is farthest from the outer edge among the plurality of protrusions.

3. The lens of claim 1 or 2.

4. At least a portion of the exit surface is planar, Each of the plurality of protrusions is annular, the incidence surface includes a curved surface surrounded by a protrusion among the plurality of protrusions that is farthest from the outer edge, The curved surface has an axisymmetric shape with respect to a virtual axis perpendicular to the emission surface.

3. The lens of claim 1 or 2.

5. The curved surface is a convex curved surface. The lens of claim 4.

6. The plurality of protrusions constitute a Fresnel A lens according to any one of claims 1 to 5.

7. A lens according to any one of claims 1 to 6; The light source; a reflecting member that reflects a portion of the light emitted from the exit surface. Lighting fixtures.

8. The light blocking angle of the reflecting member is 30 degrees or less.

8. The lighting fixture of claim 7.

9. 0.31≦H1 / H2≦0.

88.

9. The lighting fixture of claim 8.

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